diff --git a/PREUPLOAD.cfg b/PREUPLOAD.cfg
new file mode 100644
index 0000000..ce75150
--- /dev/null
+++ b/PREUPLOAD.cfg
@@ -0,0 +1,2 @@
+[Hook Scripts]
+do_not_use_DO_NOT_MERGE = ${REPO_ROOT}/build/soong/scripts/check_do_not_merge.sh ${PREUPLOAD_COMMIT}
diff --git a/core/Makefile b/core/Makefile
index a7553f0..cb5e44c 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1014,6 +1014,15 @@
   INTERNAL_VENDOR_BOOTIMAGE_ARGS += --vendor_cmdline "$(INTERNAL_KERNEL_CMDLINE)"
 endif
 
+ifdef INTERNAL_BOOTCONFIG
+INTERNAL_VENDOR_BOOTCONFIG_TARGET := $(PRODUCT_OUT)/vendor-bootconfig.img
+$(INTERNAL_VENDOR_BOOTCONFIG_TARGET):
+	rm -f $@
+	$(foreach param,$(INTERNAL_BOOTCONFIG), \
+	 printf "%s\n" $(param) >> $@;)
+  INTERNAL_VENDOR_BOOTIMAGE_ARGS += --vendor_bootconfig $(INTERNAL_VENDOR_BOOTCONFIG_TARGET)
+endif
+
 # $(1): Build target name
 # $(2): Staging dir to be compressed
 # $(3): Build dependencies
@@ -1061,7 +1070,7 @@
 
 INSTALLED_VENDOR_BOOTIMAGE_TARGET := $(PRODUCT_OUT)/vendor_boot.img
 $(INSTALLED_VENDOR_BOOTIMAGE_TARGET): $(MKBOOTIMG) $(INTERNAL_VENDOR_RAMDISK_TARGET) $(INSTALLED_DTBIMAGE_TARGET)
-$(INSTALLED_VENDOR_BOOTIMAGE_TARGET): $(INTERNAL_VENDOR_RAMDISK_FRAGMENT_TARGETS)
+$(INSTALLED_VENDOR_BOOTIMAGE_TARGET): $(INTERNAL_VENDOR_RAMDISK_FRAGMENT_TARGETS) $(INTERNAL_VENDOR_BOOTCONFIG_TARGET)
 ifeq ($(BOARD_AVB_ENABLE),true)
 $(INSTALLED_VENDOR_BOOTIMAGE_TARGET): $(AVBTOOL) $(BOARD_AVB_VENDOR_BOOTIMAGE_KEY_PATH)
 	$(call pretty,"Target vendor_boot image: $@")
@@ -4136,6 +4145,7 @@
   mkuserimg_mke2fs \
   ota_from_target_files \
   repack_bootimg \
+  secilc \
   sefcontext_compile \
   sgdisk \
   shflags \
@@ -4598,11 +4608,15 @@
 ifdef BUILDING_VENDOR_BOOT_IMAGE
   $(BUILT_TARGET_FILES_PACKAGE): $(INTERNAL_VENDOR_RAMDISK_FILES)
   $(BUILT_TARGET_FILES_PACKAGE): $(INTERNAL_VENDOR_RAMDISK_FRAGMENT_TARGETS)
+  # The vendor ramdisk may be built from the recovery ramdisk.
+  ifeq (true,$(BOARD_MOVE_RECOVERY_RESOURCES_TO_VENDOR_BOOT))
+    $(BUILT_TARGET_FILES_PACKAGE): $(INTERNAL_RECOVERY_RAMDISK_FILES_TIMESTAMP)
+  endif
 endif
 
 ifdef BUILDING_RECOVERY_IMAGE
   # TODO(b/30414428): Can't depend on INTERNAL_RECOVERYIMAGE_FILES alone like other
-  # BUILD_TARGET_FILES_PACKAGE dependencies because currently there're cp/rsync/rm
+  # BUILT_TARGET_FILES_PACKAGE dependencies because currently there're cp/rsync/rm
   # commands in build-recoveryimage-target, which would touch the files under
   # TARGET_RECOVERY_OUT and race with packaging target-files.zip.
   ifeq ($(BOARD_USES_RECOVERY_AS_BOOT),true)
@@ -4793,6 +4807,9 @@
 ifdef INSTALLED_DTBIMAGE_TARGET
 	cp $(INSTALLED_DTBIMAGE_TARGET) $(zip_root)/VENDOR_BOOT/dtb
 endif
+ifdef INTERNAL_VENDOR_BOOTCONFIG_TARGET
+	cp $(INTERNAL_VENDOR_BOOTCONFIG_TARGET) $(zip_root)/VENDOR_BOOT/vendor_bootconfig
+endif
 ifdef BOARD_KERNEL_BASE
 	echo "$(BOARD_KERNEL_BASE)" > $(zip_root)/VENDOR_BOOT/base
 endif
diff --git a/core/app_prebuilt_internal.mk b/core/app_prebuilt_internal.mk
index 5767996..ad96b5b 100644
--- a/core/app_prebuilt_internal.mk
+++ b/core/app_prebuilt_internal.mk
@@ -104,17 +104,19 @@
 
 my_enforced_uses_libraries :=
 ifdef LOCAL_ENFORCE_USES_LIBRARIES
-  my_enforced_uses_libraries := $(intermediates.COMMON)/enforce_uses_libraries.timestamp
+  my_enforced_uses_libraries := $(intermediates.COMMON)/enforce_uses_libraries.status
   $(my_enforced_uses_libraries): PRIVATE_USES_LIBRARIES := $(LOCAL_USES_LIBRARIES)
   $(my_enforced_uses_libraries): PRIVATE_OPTIONAL_USES_LIBRARIES := $(LOCAL_OPTIONAL_USES_LIBRARIES)
+  $(my_enforced_uses_libraries): PRIVATE_RELAX_CHECK := $(RELAX_USES_LIBRARY_CHECK)
   $(my_enforced_uses_libraries): $(BUILD_SYSTEM)/verify_uses_libraries.sh $(AAPT)
   $(my_enforced_uses_libraries): $(my_prebuilt_src_file)
 	@echo Verifying uses-libraries: $<
+	rm -f $@
 	aapt_binary=$(AAPT) \
 	  uses_library_names="$(strip $(PRIVATE_USES_LIBRARIES))" \
 	  optional_uses_library_names="$(strip $(PRIVATE_OPTIONAL_USES_LIBRARIES))" \
-	  $(BUILD_SYSTEM)/verify_uses_libraries.sh $<
-	touch $@
+	  relax_check="$(strip $(PRIVATE_RELAX_CHECK))" \
+	  $(BUILD_SYSTEM)/verify_uses_libraries.sh $< $@
   $(built_module) : $(my_enforced_uses_libraries)
 endif
 
@@ -237,6 +239,7 @@
 $(built_module) : $(my_prebuilt_src_file) | $(ZIPALIGN) $(ZIP2ZIP) $(SIGNAPK_JAR)
 	$(transform-prebuilt-to-target)
 	$(uncompress-prebuilt-embedded-jni-libs)
+	$(remove-unwanted-prebuilt-embedded-jni-libs)
 ifeq (true, $(LOCAL_UNCOMPRESS_DEX))
 	$(uncompress-dexs)
 endif  # LOCAL_UNCOMPRESS_DEX
diff --git a/core/board_config.mk b/core/board_config.mk
index 183bdbb..245a639 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -25,6 +25,7 @@
 _board_strip_readonly_list += BOARD_HAVE_BLUETOOTH
 _board_strip_readonly_list += BOARD_INSTALLER_CMDLINE
 _board_strip_readonly_list += BOARD_KERNEL_CMDLINE
+_board_strip_readonly_list += BOARD_BOOTCONFIG
 _board_strip_readonly_list += BOARD_KERNEL_BASE
 _board_strip_readonly_list += BOARD_USES_GENERIC_AUDIO
 _board_strip_readonly_list += BOARD_USES_RECOVERY_AS_BOOT
@@ -222,6 +223,7 @@
 .KATI_READONLY := $(_board_strip_readonly_list)
 
 INTERNAL_KERNEL_CMDLINE := $(BOARD_KERNEL_CMDLINE)
+INTERNAL_BOOTCONFIG := $(BOARD_BOOTCONFIG)
 
 ifneq ($(filter %64,$(TARGET_ARCH)),)
   TARGET_IS_64_BIT := true
diff --git a/core/config.mk b/core/config.mk
index ed6429a..3bd3622 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -149,14 +149,14 @@
   2ND_TARGET_PROJECT_SYSTEM_INCLUDES \
   ,Project include variables have been removed)
 $(KATI_obsolete_var TARGET_PREFER_32_BIT TARGET_PREFER_32_BIT_APPS TARGET_PREFER_32_BIT_EXECUTABLES)
-$(KATI_obsolete_var PRODUCT_ARTIFACT_SYSTEM_CERTIFICATE_REQUIREMENT_WHITELIST,Use PRODUCT_ARTIFACT_SYSTEM_CERTIFICATE_REQUIREMENT_ALLOW_LIST.)
-$(KATI_obsolete_var PRODUCT_ARTIFACT_PATH_REQUIREMENT_WHITELIST,Use PRODUCT_ARTIFACT_PATH_REQUIREMENT_ALLOWED_LIST.)
+$(KATI_obsolete_var PRODUCT_ARTIFACT_SYSTEM_CERTIFICATE_REQUIREMENT_WHITELIST,Use PRODUCT_ARTIFACT_SYSTEM_CERTIFICATE_REQUIREMENT_ALLOW_LIST)
+$(KATI_obsolete_var PRODUCT_ARTIFACT_PATH_REQUIREMENT_WHITELIST,Use PRODUCT_ARTIFACT_PATH_REQUIREMENT_ALLOWED_LIST)
 $(KATI_obsolete_var COVERAGE_PATHS,Use NATIVE_COVERAGE_PATHS instead)
 $(KATI_obsolete_var COVERAGE_EXCLUDE_PATHS,Use NATIVE_COVERAGE_EXCLUDE_PATHS instead)
-$(KATI_obsolete_var BOARD_VNDK_RUNTIME_DISABLE,VNDK-Lite is no longer supported.)
-$(KATI_obsolete_var LOCAL_SANITIZE_BLACKLIST,Use LOCAL_SANITIZE_BLOCKLIST instead.)
-$(KATI_deprecated_var BOARD_PLAT_PUBLIC_SEPOLICY_DIR,Use SYSTEM_EXT_PUBLIC_SEPOLICY_DIRS instead.)
-$(KATI_deprecated_var BOARD_PLAT_PRIVATE_SEPOLICY_DIR,Use SYSTEM_EXT_PRIVATE_SEPOLICY_DIRS instead.)
+$(KATI_obsolete_var BOARD_VNDK_RUNTIME_DISABLE,VNDK-Lite is no longer supported)
+$(KATI_obsolete_var LOCAL_SANITIZE_BLACKLIST,Use LOCAL_SANITIZE_BLOCKLIST instead)
+$(KATI_deprecated_var BOARD_PLAT_PUBLIC_SEPOLICY_DIR,Use SYSTEM_EXT_PUBLIC_SEPOLICY_DIRS instead)
+$(KATI_deprecated_var BOARD_PLAT_PRIVATE_SEPOLICY_DIR,Use SYSTEM_EXT_PRIVATE_SEPOLICY_DIRS instead)
 $(KATI_obsolete_var TARGET_NO_VENDOR_BOOT,Use PRODUCT_BUILD_VENDOR_BOOT_IMAGE instead)
 
 # Used to force goals to build.  Only use for conditionally defined goals.
@@ -479,6 +479,17 @@
 USE_D8 := true
 .KATI_READONLY := USE_D8
 
+# Whether to fail immediately if verify_uses_libraries check fails, or to keep
+# going and restrict dexpreopt to not compile any code for the failed module.
+#
+# The intended use case for this flag is to have a smoother migration path for
+# the Java modules that need to add <uses-library> information in their build
+# files. The flag allows to quickly silence build errors. This flag should be
+# used with caution and only as a temporary measure, as it masks real errors
+# and affects performance.
+RELAX_USES_LIBRARY_CHECK ?= false
+.KATI_READONLY := RELAX_USES_LIBRARY_CHECK
+
 #
 # Tools that are prebuilts for TARGET_BUILD_USE_PREBUILT_SDKS
 #
diff --git a/core/definitions.mk b/core/definitions.mk
index 5f0bf55..2883f0d 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -556,7 +556,7 @@
   $(foreach m, $(ALL_MODULES), \
     $(eval ALL_MODULES.$(m).NOTICE_DEPS := \
       $(sort \
-         $(foreach d,$(ALL_MODULES.$(m).NOTICE_DEPS), \
+         $(foreach d,$(sort $(ALL_MODULES.$(m).NOTICE_DEPS)), \
            $(_lookup.$(d)) \
         ) \
       ) \
@@ -578,7 +578,9 @@
 define license-metadata-rule
 $(strip $(eval _dir := $(call license-metadata-dir)))
 $(strip $(eval _deps := $(sort $(filter-out $(_dir)/$(1).meta_lic,$(foreach d,$(ALL_MODULES.$(1).NOTICE_DEPS), $(_dir)/$(d).meta_lic)))))
-$(foreach b,$(sort $(ALL_MODULES.$(1).BUILT) $(ALL_MODULES.$(1).INSTALLED)),
+$(strip $(eval _notices := $(sort $(ALL_MODULES.$(1).NOTICES))))
+$(strip $(eval _tgts := $(sort $(ALL_MODULES.$(1).BUILT) $(ALL_MODULES.$(1).INSTALLED))))
+$(foreach b,$(_tgts),
 $(_dir)/$(b).meta_module ::
 	mkdir -p $$(dir $$@)
 	echo $(_dir)/$(1).meta_lic >> $$@
@@ -587,31 +589,46 @@
 )
 $(_dir)/$(1).meta_lic: PRIVATE_KINDS := $(sort $(ALL_MODULES.$(1).LICENSE_KINDS))
 $(_dir)/$(1).meta_lic: PRIVATE_CONDITIONS := $(sort $(ALL_MODULES.$(1).LICENSE_CONDITIONS))
-$(_dir)/$(1).meta_lic: PRIVATE_NOTICES := $(sort $(ALL_MODULES.$(1).NOTICES))
+$(_dir)/$(1).meta_lic: PRIVATE_NOTICES := $(_notices)
 $(_dir)/$(1).meta_lic: PRIVATE_NOTICE_DEPS := $(_deps)
-$(_dir)/$(1).meta_lic: PRIVATE_TARGETS := $(sort $(ALL_MODULES.$(1).BUILT) $(ALL_MODULES.$(1).INSTALLED))
-$(_dir)/$(1).meta_lic: PRIVATE_IS_CONTAINER := $(sort $(ALL_MODULES.$(1).IS_CONTAINER))
-$(_dir)/$(1).meta_lic: PRIVATE_PACKAGE_NAME := $(ALL_MODULES.$(1).LICENSE_PACKAGE_NAME)
+$(_dir)/$(1).meta_lic: PRIVATE_TARGETS := $(_tgts)
+$(_dir)/$(1).meta_lic: PRIVATE_IS_CONTAINER := $(ALL_MODULES.$(1).IS_CONTAINER)
+$(_dir)/$(1).meta_lic: PRIVATE_PACKAGE_NAME := $(strip $(ALL_MODULES.$(1).LICENSE_PACKAGE_NAME))
 $(_dir)/$(1).meta_lic: PRIVATE_INSTALL_MAP := $(sort $(ALL_MODULES.$(1).LICENSE_INSTALL_MAP))
-$(_dir)/$(1).meta_lic : $(_deps) $(ALL_MODULES.$(1).NOTICES) $(foreach b,$(sort $(ALL_MODULES.$(1).BUILT) $(ALL_MODULES.$(1).INSTALLED)), $(_dir)/$(b).meta_module) build/make/tools/build-license-metadata.sh
+$(_dir)/$(1).meta_lic : $(_deps) $(_notices) $(foreach b,$(_tgts), $(_dir)/$(b).meta_module) build/make/tools/build-license-metadata.sh
 	rm -f $$@
 	mkdir -p $$(dir $$@)
-	build/make/tools/build-license-metadata.sh -k $$(PRIVATE_KINDS) -c $$(PRIVATE_CONDITIONS) -n $$(PRIVATE_NOTICES) -d $$(PRIVATE_NOTICE_DEPS) -m $$(PRIVATE_INSTALL_MAP) -t $$(PRIVATE_TARGETS) $$(if $$(filter-out false,$$(PRIVATE_IS_CONTAINER)),-is_container) -p $$(PRIVATE_PACKAGE_NAME) -o $$@
-
-$(1) : $(_dir)/$(1).meta_lic
-
-$(if $(ALL_MODULES.$(1).INSTALLED_NOTICE_FILE),$(ALL_MODULES.$(1).INSTALLED_NOTICE_FILE) : $(_dir)/$(1).meta_lic)
+	build/make/tools/build-license-metadata.sh -k $$(PRIVATE_KINDS) -c $$(PRIVATE_CONDITIONS) -n $$(PRIVATE_NOTICES) -d $$(PRIVATE_NOTICE_DEPS) -m $$(PRIVATE_INSTALL_MAP) -t $$(PRIVATE_TARGETS) $$(if $$(PRIVATE_IS_CONTAINER),-is_container) -p $$(PRIVATE_PACKAGE_NAME) -o $$@
 
 .PHONY: $(1).meta_lic
 $(1).meta_lic : $(_dir)/$(1).meta_lic
 
+$(strip $(eval _mifs := $(sort $(ALL_MODULES.$(1).MODULE_INSTALLED_FILENAMES))))
+$(strip $(eval _infs := $(sort $(ALL_MODULES.$(1).INSTALLED_NOTICE_FILE))))
+
+# Emit each installed notice file rule if it references the current module
+$(if $(_infs),$(foreach inf,$(_infs),
+$(if $(strip $(filter $(1),$(INSTALLED_NOTICE_FILES.$(inf).MODULE))),
+$(strip $(eval _mif := $(firstword $(foreach m,$(_mifs),$(if $(filter %/src/$(m).txt,$(inf)),$(m))))))
+
+$(inf) : $(_dir)/$(1).meta_lic
+$(inf): PRIVATE_INSTALLED_MODULE := $(_mif)
+$(inf) : PRIVATE_NOTICES := $(_notices)
+
+$(inf): $(_notices)
+	@echo Notice file: $$< -- $$@
+	mkdir -p $$(dir $$@)
+	awk 'FNR==1 && NR > 1 {print "\n"} {print}' $$(PRIVATE_NOTICES) > $$@
+
+)))
+
 endef
 
 ###########################################################
 ## Declares a license metadata build rule for ALL_MODULES
 ###########################################################
 define build-license-metadata
-$(foreach m,$(ALL_MODULES),$(eval $(call license-metadata-rule,$(m))))
+$(foreach m,$(sort $(ALL_MODULES)),$(eval $(call license-metadata-rule,$(m))))
 endef
 
 ###########################################################
@@ -2396,14 +2413,19 @@
 #
 define uncompress-prebuilt-embedded-jni-libs
   if (zipinfo $@ 'lib/*.so' 2>/dev/null | grep -v ' stor ' >/dev/null) ; then \
-    $(ZIP2ZIP) -i $@ -o $@.tmp -0 'lib/**/*.so' \
-      $(if $(PRIVATE_EMBEDDED_JNI_LIBS), \
-        -x 'lib/**/*.so' \
-        $(addprefix -X ,$(PRIVATE_EMBEDDED_JNI_LIBS))) && \
-    mv -f $@.tmp $@ ; \
+    $(ZIP2ZIP) -i $@ -o $@.tmp -0 'lib/**/*.so' && mv -f $@.tmp $@ ; \
   fi
 endef
 
+# Remove unwanted shared JNI libraries embedded in an apk.
+#
+define remove-unwanted-prebuilt-embedded-jni-libs
+  $(if $(PRIVATE_EMBEDDED_JNI_LIBS), \
+    $(ZIP2ZIP) -i $@ -o $@.tmp \
+      -x 'lib/**/*.so' $(addprefix -X ,$(PRIVATE_EMBEDDED_JNI_LIBS)) && \
+    mv -f $@.tmp $@)
+endef
+
 # TODO(joeo): If we can ever upgrade to post 3.81 make and get the
 # new prebuilt rules to work, we should change this to copy the
 # resources to the out directory and then copy the resources.
@@ -2765,7 +2787,8 @@
     $(R8_DEBUG_MODE) \
     $(PRIVATE_PROGUARD_FLAGS) \
     $(addprefix -injars , $(PRIVATE_EXTRA_INPUT_JAR)) \
-    $(PRIVATE_DX_FLAGS)
+    $(PRIVATE_DX_FLAGS) \
+    -ignorewarnings
 $(hide) touch $(PRIVATE_PROGUARD_DICTIONARY)
 endef
 
diff --git a/core/dex_preopt_config.mk b/core/dex_preopt_config.mk
index 06e2fb7..dda7de0 100644
--- a/core/dex_preopt_config.mk
+++ b/core/dex_preopt_config.mk
@@ -105,6 +105,7 @@
   $(call add_json_bool, IsEng,                                   $(filter eng,$(TARGET_BUILD_VARIANT)))
   $(call add_json_bool, SanitizeLite,                            $(SANITIZE_LITE))
   $(call add_json_bool, DefaultAppImages,                        $(WITH_DEX_PREOPT_APP_IMAGE))
+  $(call add_json_bool, RelaxUsesLibraryCheck,                   $(filter true,$(RELAX_USES_LIBRARY_CHECK)))
   $(call add_json_str,  Dex2oatXmx,                              $(DEX2OAT_XMX))
   $(call add_json_str,  Dex2oatXms,                              $(DEX2OAT_XMS))
   $(call add_json_str,  EmptyDirectory,                          $(OUT_DIR)/empty)
diff --git a/core/dex_preopt_odex_install.mk b/core/dex_preopt_odex_install.mk
index f9a9ba7..cbd3069 100644
--- a/core/dex_preopt_odex_install.mk
+++ b/core/dex_preopt_odex_install.mk
@@ -278,6 +278,7 @@
   $(call add_json_list, PreoptFlags,                    $(LOCAL_DEX_PREOPT_FLAGS))
   $(call add_json_str,  ProfileClassListing,            $(if $(my_process_profile),$(LOCAL_DEX_PREOPT_PROFILE)))
   $(call add_json_bool, ProfileIsTextListing,           $(my_profile_is_text_listing))
+  $(call add_json_str,  EnforceUsesLibrariesStatusFile, $(intermediates.COMMON)/enforce_uses_libraries.status)
   $(call add_json_bool, EnforceUsesLibraries,           $(LOCAL_ENFORCE_USES_LIBRARIES))
   $(call add_json_str,  ProvidesUsesLibrary,            $(firstword $(LOCAL_PROVIDES_USES_LIBRARY) $(LOCAL_MODULE)))
   $(call add_json_map,  ClassLoaderContexts)
@@ -345,6 +346,9 @@
       $(call intermediates-dir-for,JAVA_LIBRARIES,$(lib),,COMMON)/javalib.jar)
   my_dexpreopt_deps += $(my_dexpreopt_images_deps)
   my_dexpreopt_deps += $(DEXPREOPT_BOOTCLASSPATH_DEX_FILES)
+  ifeq ($(LOCAL_ENFORCE_USES_LIBRARIES),true)
+    my_dexpreopt_deps += $(intermediates.COMMON)/enforce_uses_libraries.status
+  endif
 
   $(my_dexpreopt_zip): PRIVATE_MODULE := $(LOCAL_MODULE)
   $(my_dexpreopt_zip): $(my_dexpreopt_deps)
diff --git a/core/dumpconfig.mk b/core/dumpconfig.mk
new file mode 100644
index 0000000..9b1f2c2
--- /dev/null
+++ b/core/dumpconfig.mk
@@ -0,0 +1,144 @@
+# Read and dump the product configuration.
+
+# Called from the product-config tool, not from the main build system.
+
+#
+# Ensure we are being called correctly
+#
+ifndef KATI
+    $(warning Kati must be used to call dumpconfig.mk, not make.)
+    $(error stopping)
+endif
+
+ifdef DEFAULT_GOAL
+    $(warning Calling dumpconfig.mk from inside the make build system is not)
+    $(warning supported. It is only meant to be called via kati by product-confing.)
+    $(error stopping)
+endif
+
+ifndef TARGET_PRODUCT
+    $(warning dumpconfig.mk requires TARGET_PRODUCT to be set)
+    $(error stopping)
+endif
+
+ifndef TARGET_BUILD_VARIANT
+    $(warning dumpconfig.mk requires TARGET_BUILD_VARIANT to be set)
+    $(error stopping)
+endif
+
+ifneq (build/make/core/config.mk,$(wildcard build/make/core/config.mk))
+    $(warning dumpconfig must be called from the root of the source tree)
+    $(error stopping)
+endif
+
+ifeq (,$(DUMPCONFIG_FILE))
+    $(warning dumpconfig requires DUMPCONFIG_FILE to be set)
+    $(error stopping)
+endif
+
+# Skip the second inclusion of all of the product config files, because
+# we will do these checks in the product_config tool.
+SKIP_ARTIFACT_PATH_REQUIREMENT_PRODUCTS_CHECK := true
+
+# Before we do anything else output the format version.
+$(file > $(DUMPCONFIG_FILE),dumpconfig_version,1)
+$(file >> $(DUMPCONFIG_FILE),dumpconfig_file,$(DUMPCONFIG_FILE))
+
+# Default goal for dumpconfig
+dumpconfig:
+	$(file >> $(DUMPCONFIG_FILE),***DONE***)
+	@echo ***DONE***
+
+# TODO(Remove): These need to be set externally
+OUT_DIR := out
+TMPDIR = /tmp/build-temp
+BUILD_DATETIME_FILE := $(OUT_DIR)/build_date.txt
+
+# Escape quotation marks for CSV, and wraps in quotation marks.
+define escape-for-csv
+"$(subst ","",$1)"
+endef
+
+# Args:
+#   $(1): include stack
+define dump-import-start
+$(eval $(file >> $(DUMPCONFIG_FILE),import,$(strip $(1))))
+endef
+
+# Args:
+#   $(1): include stack
+define dump-import-done
+$(eval $(file >> $(DUMPCONFIG_FILE),imported,$(strip $(1))))
+endef
+
+# Args:
+#   $(1): Current file
+#   $(2): Inherited file
+define dump-inherit
+$(eval $(file >> $(DUMPCONFIG_FILE),inherit,$(strip $(1)),$(strip $(2))))
+endef
+
+# Args:
+#   $(1): Config phase (PRODUCT, EXPAND, or DEVICE)
+#   $(2): Root nodes to import
+#   $(3): All variable names
+#   $(4): Single-value variables
+#   $(5): Makefile being processed
+define dump-phase-start
+$(eval $(file >> $(DUMPCONFIG_FILE),phase,$(strip $(1)),$(strip $(2)))) \
+$(foreach var,$(3), \
+    $(eval $(file >> $(DUMPCONFIG_FILE),var,$(if $(filter $(4),$(var)),single,list),$(var))) \
+) \
+$(call dump-config-vals,$(strip $(5)),initial)
+endef
+
+# Args:
+#   $(1): Makefile being processed
+define dump-phase-end
+$(call dump-config-vals,$(strip $(1)),final)
+endef
+
+define dump-debug
+$(eval $(file >> $(DUMPCONFIG_FILE),debug,$(1)))
+endef
+
+# Skip these when dumping. They're not used and they cause a lot of noise in the dump.
+DUMPCONFIG_SKIP_VARS := \
+	.VARIABLES \
+	.KATI_SYMBOLS \
+	1 \
+	2 \
+	3 \
+	4 \
+	5 \
+	6 \
+	7 \
+	8 \
+	9 \
+	LOCAL_PATH \
+	MAKEFILE_LIST \
+	PARENT_PRODUCT_FILES \
+	current_mk \
+	_eiv_ev \
+	_eiv_i \
+	_eiv_sv \
+	_eiv_tv \
+	inherit_var \
+	np \
+	_node_import_context \
+	_included \
+	_include_stack \
+	_in \
+	_nic.%
+
+# Args:
+#   $(1): Makefile that was included
+#   $(2): block (before,import,after,initial,final)
+define dump-config-vals
+$(foreach var,$(filter-out $(DUMPCONFIG_SKIP_VARS),$(.KATI_SYMBOLS)),\
+    $(eval $(file >> $(DUMPCONFIG_FILE),val,$(call escape-for-csv,$(1)),$(2),$(call escape-for-csv,$(var)),$(call escape-for-csv,$($(var))),$(call escape-for-csv,$(KATI_variable_location $(var))))) \
+)
+endef
+
+include build/make/core/config.mk
+
diff --git a/core/node_fns.mk b/core/node_fns.mk
index b81d60c..8d20160 100644
--- a/core/node_fns.mk
+++ b/core/node_fns.mk
@@ -195,7 +195,11 @@
   $(call clear-var-list, $(3))
   $(eval LOCAL_PATH := $(patsubst %/,%,$(dir $(2))))
   $(eval MAKEFILE_LIST :=)
+  $(call dump-import-start,$(_include_stack))
+  $(call dump-config-vals,$(2),before)
   $(eval include $(2))
+  $(call dump-import-done,$(_include_stack))
+  $(call dump-config-vals,$(2),after)
   $(eval _included := $(filter-out $(2),$(MAKEFILE_LIST)))
   $(eval MAKEFILE_LIST :=)
   $(eval LOCAL_PATH :=)
@@ -250,6 +254,7 @@
 #       of the default list semantics
 #
 define import-nodes
+$(call dump-phase-start,$(1),$(2),$(3),$(4),build/make/core/node_fns.mk) \
 $(if \
   $(foreach _in,$(2), \
     $(eval _node_import_context := _nic.$(1).[[$(_in)]]) \
@@ -263,5 +268,6 @@
     $(if $(_include_stack),$(eval $(error ASSERTION FAILED: _include_stack \
                 should be empty here: $(_include_stack))),) \
    ) \
-,)
+,) \
+$(call dump-phase-end,build/make/core/node_fns.mk)
 endef
diff --git a/core/notice_files.mk b/core/notice_files.mk
index 89f822b..9678380 100644
--- a/core/notice_files.mk
+++ b/core/notice_files.mk
@@ -80,7 +80,7 @@
 ifeq (true,$(is_container))
 # Include shared libraries' notices for "container" types, but not for binaries etc.
 notice_deps := \
-    $(sort \
+    $(strip \
         $(LOCAL_REQUIRED_MODULES) \
         $(LOCAL_STATIC_LIBRARIES) \
         $(LOCAL_WHOLE_STATIC_LIBRARIES) \
@@ -95,7 +95,7 @@
     )
 else
 notice_deps := \
-    $(sort \
+    $(strip \
         $(LOCAL_REQUIRED_MODULES) \
         $(LOCAL_STATIC_LIBRARIES) \
         $(LOCAL_WHOLE_STATIC_LIBRARIES) \
@@ -106,24 +106,24 @@
     )
 endif
 ifeq ($(LOCAL_IS_HOST_MODULE),true)
-notice_deps := $(sort $(notice_deps) $(LOCAL_HOST_REQUIRED_MODULES))
+notice_deps := $(strip $(notice_deps) $(LOCAL_HOST_REQUIRED_MODULES))
 else
-notice_deps := $(sort $(notice_deps) $(LOCAL_TARGET_REQUIRED_MODULES))
+notice_deps := $(strip $(notice_deps) $(LOCAL_TARGET_REQUIRED_MODULES))
 endif
 
 ifdef my_register_name
 ALL_MODULES.$(my_register_name).LICENSE_PACKAGE_NAME := $(strip $(license_package_name))
-ALL_MODULES.$(my_register_name).LICENSE_KINDS := $(sort $(ALL_MODULES.$(my_register_name).LICENSE_KINDS) $(license_kinds))
-ALL_MODULES.$(my_register_name).LICENSE_CONDITIONS := $(sort $(ALL_MODULES.$(my_register_name).LICENSE_CONDITIONS) $(license_conditions))
-ALL_MODULES.$(my_register_name).LICENSE_INSTALL_MAP := $(sort $(ALL_MODULES.$(my_register_name).LICENSE_INSTALL_MAP) $(install_map))
-ALL_MODULES.$(my_register_name).NOTICE_DEPS := $(sort $(ALL_MODULES.$(my_register_name).NOTICE_DEPS) $(notice_deps))
-ALL_MODULES.$(my_register_name).IS_CONTAINER := $(sort $(ALL_MODULES.$(my_register_name).IS_CONTAINER) $(is_container))
+ALL_MODULES.$(my_register_name).LICENSE_KINDS := $(ALL_MODULES.$(my_register_name).LICENSE_KINDS) $(license_kinds)
+ALL_MODULES.$(my_register_name).LICENSE_CONDITIONS := $(ALL_MODULES.$(my_register_name).LICENSE_CONDITIONS) $(license_conditions)
+ALL_MODULES.$(my_register_name).LICENSE_INSTALL_MAP := $(ALL_MODULES.$(my_register_name).LICENSE_INSTALL_MAP) $(install_map)
+ALL_MODULES.$(my_register_name).NOTICE_DEPS := $(ALL_MODULES.$(my_register_name).NOTICE_DEPS) $(notice_deps)
+ALL_MODULES.$(my_register_name).IS_CONTAINER := $(strip $(filter-out false,$(ALL_MODULES.$(my_register_name).IS_CONTAINER) $(is_container)))
 endif
 
 ifdef notice_file
 
 ifdef my_register_name
-ALL_MODULES.$(my_register_name).NOTICES := $(sort $(ALL_MODULES.$(my_register_name).NOTICES) $(notice_file))
+ALL_MODULES.$(my_register_name).NOTICES := $(ALL_MODULES.$(my_register_name).NOTICES) $(notice_file)
 endif
 
 # This relies on the name of the directory in PRODUCT_OUT matching where
@@ -180,9 +180,10 @@
 installed_notice_file := $($(my_prefix)OUT_NOTICE_FILES)/src/$(module_installed_filename).txt
 
 ifdef my_register_name
-ALL_MODULES.$(my_register_name).INSTALLED_NOTICE_FILE := $(installed_notice_file)
-endif
-
+ALL_MODULES.$(my_register_name).INSTALLED_NOTICE_FILE := $(ALL_MODULES.$(my_register_name).INSTALLED_NOTICE_FILE) $(installed_notice_file)
+ALL_MODULES.$(my_register_name).MODULE_INSTALLED_FILENAMES := $(ALL_MODULES.$(my_register_name).MODULE_INSTALLED_FILENAMES) $(module_installed_filename)
+INSTALLED_NOTICE_FILES.$(installed_notice_file).MODULE := $(my_register_name)
+else
 $(installed_notice_file): PRIVATE_INSTALLED_MODULE := $(module_installed_filename)
 $(installed_notice_file) : PRIVATE_NOTICES := $(notice_file)
 
@@ -190,6 +191,7 @@
 	@echo Notice file: $< -- $@
 	$(hide) mkdir -p $(dir $@)
 	$(hide) awk 'FNR==1 && NR > 1 {print "\n"} {print}' $(PRIVATE_NOTICES) > $@
+endif
 
 ifdef LOCAL_INSTALLED_MODULE
 # Make LOCAL_INSTALLED_MODULE depend on NOTICE files if they exist
diff --git a/core/package_internal.mk b/core/package_internal.mk
index 1b40624..346ca24 100644
--- a/core/package_internal.mk
+++ b/core/package_internal.mk
@@ -101,7 +101,6 @@
 enforce_rro_enabled :=
 ifneq (,$(filter *, $(PRODUCT_ENFORCE_RRO_TARGETS)))
   # * means all system and system_ext APKs, so enable conditionally based on module path.
-  # Note that modules in PRODUCT_ENFORCE_RRO_EXEMPTED_TARGETS are excluded even if it is '*'
 
   # Note that base_rules.mk has not yet been included, so it's likely that only
   # one of LOCAL_MODULE_PATH and the LOCAL_X_MODULE flags has been set.
@@ -120,12 +119,6 @@
   enforce_rro_enabled := true
 endif
 
-# TODO(b/150820813) Some modules depend on static overlay, remove this after eliminating the dependency.
-ifneq (,$(filter $(LOCAL_PACKAGE_NAME), $(PRODUCT_ENFORCE_RRO_EXEMPTED_TARGETS)))
-  enforce_rro_enabled :=
-endif
-
-
 product_package_overlays := $(strip \
     $(wildcard $(foreach dir, $(PRODUCT_PACKAGE_OVERLAYS), \
       $(addprefix $(dir)/, $(LOCAL_RESOURCE_DIR)))))
diff --git a/core/product.mk b/core/product.mk
index ce9bacf..8976dd9 100644
--- a/core/product.mk
+++ b/core/product.mk
@@ -195,9 +195,6 @@
 # Package list to apply enforcing RRO.
 _product_list_vars += PRODUCT_ENFORCE_RRO_TARGETS
 
-# Packages to skip auto-generating RROs for when PRODUCT_ENFORCE_RRO_TARGETS is set to *.
-_product_list_vars += PRODUCT_ENFORCE_RRO_EXEMPTED_TARGETS
-
 _product_list_vars += PRODUCT_SDK_ATREE_FILES
 _product_list_vars += PRODUCT_SDK_ADDON_NAME
 _product_list_vars += PRODUCT_SDK_ADDON_COPY_FILES
@@ -460,7 +457,9 @@
   $(eval current_mk := $(strip $(word 1,$(_include_stack)))) \
   $(eval inherit_var := PRODUCTS.$(current_mk).INHERITS_FROM) \
   $(eval $(inherit_var) := $(sort $($(inherit_var)) $(np))) \
-  $(eval PARENT_PRODUCT_FILES := $(sort $(PARENT_PRODUCT_FILES) $(current_mk)))
+  $(eval PARENT_PRODUCT_FILES := $(sort $(PARENT_PRODUCT_FILES) $(current_mk))) \
+  $(call dump-inherit,$(strip $(word 1,$(_include_stack))),$(1)) \
+  $(call dump-config-vals,$(current_mk),inherit)
 endef
 
 # Specifies a number of path prefixes, relative to PRODUCT_OUT, where the
@@ -607,6 +606,8 @@
 # to a shorthand that is more convenient to read from elsewhere.
 #
 define strip-product-vars
+$(call dump-phase-start,PRODUCT-EXPAND,,$(_product_var_list),$(_product_single_value_vars), \
+		build/make/core/product.mk) \
 $(foreach v,\
   $(_product_var_list) \
     PRODUCT_ENFORCE_PACKAGES_EXIST \
@@ -614,7 +615,8 @@
   $(eval $(v) := $(strip $(PRODUCTS.$(INTERNAL_PRODUCT).$(v)))) \
   $(eval get-product-var = $$(if $$(filter $$(1),$$(INTERNAL_PRODUCT)),$$($$(2)),$$(PRODUCTS.$$(strip $$(1)).$$(2)))) \
   $(KATI_obsolete_var PRODUCTS.$(INTERNAL_PRODUCT).$(v),Use $(v) instead) \
-)
+) \
+$(call dump-phase-end,build/make/core/product.mk)
 endef
 
 define add-to-product-copy-files-if-exists
diff --git a/core/product_config.mk b/core/product_config.mk
index 7b72b5e..11ffade 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -146,6 +146,11 @@
 endif
 endif
 
+ifneq ($(ALLOW_RULES_IN_PRODUCT_CONFIG),)
+_product_config_saved_KATI_ALLOW_RULES := $(.KATI_ALLOW_RULES)
+.KATI_ALLOW_RULES := $(ALLOW_RULES_IN_PRODUCT_CONFIG)
+endif
+
 ifeq ($(load_all_product_makefiles),true)
 # Import all product makefiles.
 $(call import-products, $(all_product_makefiles))
@@ -163,12 +168,19 @@
 # Quick check
 $(check-all-products)
 
+ifeq ($(SKIP_ARTIFACT_PATH_REQUIREMENT_PRODUCTS_CHECK),)
 # Import all the products that have made artifact path requirements, so that we can verify
 # the artifacts they produce.
 # These are imported after check-all-products because some of them might not be real products.
 $(foreach makefile,$(ARTIFACT_PATH_REQUIREMENT_PRODUCTS),\
   $(if $(filter-out $(makefile),$(PRODUCTS)),$(eval $(call import-products,$(makefile))))\
 )
+endif
+
+ifneq ($(ALLOW_RULES_IN_PRODUCT_CONFIG),)
+.KATI_ALLOW_RULES := $(_saved_KATI_ALLOW_RULES)
+_product_config_saved_KATI_ALLOW_RULES :=
+endif
 
 ifneq ($(filter dump-products, $(MAKECMDGOALS)),)
 $(dump-products)
@@ -181,14 +193,16 @@
 ifneq ($(current_product_makefile),$(INTERNAL_PRODUCT))
 $(error PRODUCT_NAME inconsistent in $(current_product_makefile) and $(INTERNAL_PRODUCT))
 endif
-current_product_makefile :=
-all_product_makefiles :=
-all_product_configs :=
+
 
 ############################################################################
 # Strip and assign the PRODUCT_ variables.
 $(call strip-product-vars)
 
+current_product_makefile :=
+all_product_makefiles :=
+all_product_configs :=
+
 #############################################################################
 # Quick check and assign default values
 
@@ -401,6 +415,11 @@
 $(KATI_obsolete_var PRODUCT_USE_PRODUCT_VNDK,Use PRODUCT_PRODUCT_VNDK_VERSION instead)
 $(KATI_obsolete_var PRODUCT_USE_PRODUCT_VNDK_OVERRIDE,Use PRODUCT_PRODUCT_VNDK_VERSION instead)
 
+ifdef PRODUCT_ENFORCE_RRO_EXEMPTED_TARGETS
+    $(error PRODUCT_ENFORCE_RRO_EXEMPTED_TARGETS is deprecated, consider using RRO for \
+      $(PRODUCT_ENFORCE_RRO_EXEMPTED_TARGETS))
+endif
+
 define product-overrides-config
 $$(foreach rule,$$(PRODUCT_$(1)_OVERRIDES),\
     $$(if $$(filter 2,$$(words $$(subst :,$$(space),$$(rule)))),,\
diff --git a/core/soong_config.mk b/core/soong_config.mk
index 1569300..9fdf7b8 100644
--- a/core/soong_config.mk
+++ b/core/soong_config.mk
@@ -80,7 +80,6 @@
 $(call add_json_list, DeviceResourceOverlays,            $(DEVICE_PACKAGE_OVERLAYS))
 $(call add_json_list, ProductResourceOverlays,           $(PRODUCT_PACKAGE_OVERLAYS))
 $(call add_json_list, EnforceRROTargets,                 $(PRODUCT_ENFORCE_RRO_TARGETS))
-$(call add_json_list, EnforceRROExemptedTargets,         $(PRODUCT_ENFORCE_RRO_EXEMPTED_TARGETS))
 $(call add_json_list, EnforceRROExcludedOverlays,        $(PRODUCT_ENFORCE_RRO_EXCLUDED_OVERLAYS))
 
 $(call add_json_str,  AAPTCharacteristics,               $(TARGET_AAPT_CHARACTERISTICS))
diff --git a/core/verify_uses_libraries.sh b/core/verify_uses_libraries.sh
index dde0447..1bd0a2c 100755
--- a/core/verify_uses_libraries.sh
+++ b/core/verify_uses_libraries.sh
@@ -21,6 +21,7 @@
 
 set -e
 local_apk=$1
+status_file=$2
 badging=$(${aapt_binary} dump badging "${local_apk}")
 export sdk_version=$(echo "${badging}" | grep "sdkVersion" | sed -n "s/sdkVersion:'\(.*\)'/\1/p")
 # Export target_sdk_version to the caller.
@@ -28,20 +29,28 @@
 uses_libraries=$(echo "${badging}" | grep "uses-library" | sed -n "s/uses-library:'\(.*\)'/\1/p")
 optional_uses_libraries=$(echo "${badging}" | grep "uses-library-not-required" | sed -n "s/uses-library-not-required:'\(.*\)'/\1/p")
 
+errmsg=
+
 # Verify that the uses libraries match exactly.
 # Currently we validate the ordering of the libraries since it matters for resolution.
 single_line_libs=$(echo "${uses_libraries}" | tr '\n' ' ' | awk '{$1=$1}1')
 if [[ "${single_line_libs}" != "${uses_library_names}" ]]; then
-  echo "LOCAL_USES_LIBRARIES (${uses_library_names})" \
-       "do not match (${single_line_libs}) in manifest for ${local_apk}"
-  exit 1
+  errmsg="LOCAL_USES_LIBRARIES (${uses_library_names}) do not match (${single_line_libs}) in manifest for ${local_apk}"
 fi
 
 # Verify that the optional uses libraries match exactly.
 single_line_optional_libs=$(echo "${optional_uses_libraries}" | tr '\n' ' ' | awk '{$1=$1}1')
 if [[ "${single_line_optional_libs}" != "${optional_uses_library_names}" ]]; then
-  echo "LOCAL_OPTIONAL_USES_LIBRARIES (${optional_uses_library_names}) " \
-       "do not match (${single_line_optional_libs}) in manifest for ${local_apk}"
-  exit 1
+  errmsg="LOCAL_OPTIONAL_USES_LIBRARIES (${optional_uses_library_names}) do not match (${single_line_optional_libs}) in manifest for ${local_apk}"
 fi
 
+if [[ ! -z "${errmsg}" ]]; then
+  echo "${errmsg}" > "${status_file}"
+  if [[ "${relax_check}" != true ]]; then
+    # fail immediately
+    echo "${errmsg}"
+    exit 1
+  fi
+else
+  touch "${status_file}"
+fi
diff --git a/envsetup.sh b/envsetup.sh
index c03e2cb..58fcd3b 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -27,6 +27,7 @@
 - mangrep:    Greps on all local AndroidManifest.xml files.
 - mgrep:      Greps on all local Makefiles and *.bp files.
 - owngrep:    Greps on all local OWNERS files.
+- rsgrep:     Greps on all local Rust files.
 - sepgrep:    Greps on all local sepolicy files.
 - sgrep:      Greps on all local source files.
 - godir:      Go to the directory containing a file.
@@ -34,6 +35,7 @@
 - gomod:      Go to the directory containing a module.
 - pathmod:    Get the directory containing a module.
 - outmod:     Gets the location of a module's installed outputs with a certain extension.
+- dirmods:    Gets the modules defined in a given directory.
 - installmod: Adb installs a module's built APK.
 - refreshmod: Refresh list of modules for allmod/gomod/pathmod/outmod/installmod.
 - syswrite:   Remount partitions (e.g. system.img) as writable, rebooting if necessary.
@@ -1037,6 +1039,12 @@
         -exec grep --color -n "$@" {} +
 }
 
+function rsgrep()
+{
+    find . -name .repo -prune -o -name .git -prune -o -name out -prune -o -type f -name "*\.rs" \
+        -exec grep --color -n "$@" {} +
+}
+
 function cgrep()
 {
     find . -name .repo -prune -o -name .git -prune -o -name out -prune -o -type f \( -name '*.c' -o -name '*.cc' -o -name '*.cpp' -o -name '*.h' -o -name '*.hpp' \) \
@@ -1404,8 +1412,9 @@
     python -c "import json; print('\n'.join(sorted(json.load(open('$ANDROID_PRODUCT_OUT/module-info.json')).keys())))"
 }
 
-# Get the path of a specific module in the android tree, as cached in module-info.json. If any build change
-# is made, and it should be reflected in the output, you should run 'refreshmod' first.
+# Get the path of a specific module in the android tree, as cached in module-info.json.
+# If any build change is made, and it should be reflected in the output, you should run
+# 'refreshmod' first.  Note: This is the inverse of dirmods.
 function pathmod() {
     if [[ $# -ne 1 ]]; then
         echo "usage: pathmod <module>" >&2
@@ -1429,6 +1438,36 @@
     fi
 }
 
+# Get the path of a specific module in the android tree, as cached in module-info.json.
+# If any build change is made, and it should be reflected in the output, you should run
+# 'refreshmod' first.  Note: This is the inverse of pathmod.
+function dirmods() {
+    if [[ $# -ne 1 ]]; then
+        echo "usage: dirmods <path>" >&2
+        return 1
+    fi
+
+    verifymodinfo || return 1
+
+    python -c "import json, os
+dir = '$1'
+while dir.endswith('/'):
+    dir = dir[:-1]
+prefix = dir + '/'
+module_info = json.load(open('$ANDROID_PRODUCT_OUT/module-info.json'))
+results = set()
+for m in module_info.values():
+    for path in m.get(u'path', []):
+        if path == dir or path.startswith(prefix):
+            name = m.get(u'module_name')
+            if name:
+                results.add(name)
+for name in sorted(results):
+    print(name)
+"
+}
+
+
 # Go to a specific module in the android tree, as cached in module-info.json. If any build change
 # is made, and it should be reflected in the output, you should run 'refreshmod' first.
 function gomod() {
diff --git a/target/board/BoardConfigEmuCommon.mk b/target/board/BoardConfigEmuCommon.mk
index fe0293b..342abd7 100644
--- a/target/board/BoardConfigEmuCommon.mk
+++ b/target/board/BoardConfigEmuCommon.mk
@@ -90,6 +90,3 @@
 DEVICE_MATRIX_FILE   := device/generic/goldfish/compatibility_matrix.xml
 
 BOARD_SEPOLICY_DIRS += device/generic/goldfish/sepolicy/common
-
-# b/176210699: remove this
-BUILD_BROKEN_VENDOR_PROPERTY_NAMESPACE := true
diff --git a/target/product/base_system.mk b/target/product/base_system.mk
index 5238d40..09864bc 100644
--- a/target/product/base_system.mk
+++ b/target/product/base_system.mk
@@ -214,6 +214,7 @@
     ndc \
     netd \
     NetworkStackNext \
+    odsign \
     org.apache.http.legacy \
     otacerts \
     PackageInstaller \
diff --git a/target/product/gsi/current.txt b/target/product/gsi/current.txt
index 717d990..c753e6c 100644
--- a/target/product/gsi/current.txt
+++ b/target/product/gsi/current.txt
@@ -19,12 +19,8 @@
 LLNDK: libvndksupport.so
 LLNDK: libvulkan.so
 VNDK-SP: android.hardware.common-V2-ndk_platform.so
-VNDK-SP: android.hardware.common-unstable-ndk_platform.so
 VNDK-SP: android.hardware.common.fmq-V1-ndk_platform.so
-VNDK-SP: android.hardware.common.fmq-ndk_platform.so
-VNDK-SP: android.hardware.common.fmq-unstable-ndk_platform.so
 VNDK-SP: android.hardware.graphics.common-V2-ndk_platform.so
-VNDK-SP: android.hardware.graphics.common-unstable-ndk_platform.so
 VNDK-SP: android.hardware.graphics.common@1.0.so
 VNDK-SP: android.hardware.graphics.common@1.1.so
 VNDK-SP: android.hardware.graphics.common@1.2.so
@@ -62,10 +58,7 @@
 VNDK-SP: libz.so
 VNDK-core: android.hardware.audio.common@2.0.so
 VNDK-core: android.hardware.authsecret-V1-ndk_platform.so
-VNDK-core: android.hardware.authsecret-ndk_platform.so
-VNDK-core: android.hardware.authsecret-unstable-ndk_platform.so
 VNDK-core: android.hardware.automotive.occupant_awareness-V1-ndk_platform.so
-VNDK-core: android.hardware.automotive.occupant_awareness-ndk_platform.so
 VNDK-core: android.hardware.configstore-utils.so
 VNDK-core: android.hardware.configstore@1.0.so
 VNDK-core: android.hardware.configstore@1.1.so
@@ -76,52 +69,28 @@
 VNDK-core: android.hardware.graphics.bufferqueue@1.0.so
 VNDK-core: android.hardware.graphics.bufferqueue@2.0.so
 VNDK-core: android.hardware.health.storage-V1-ndk_platform.so
-VNDK-core: android.hardware.health.storage-ndk_platform.so
-VNDK-core: android.hardware.health.storage-unstable-ndk_platform.so
 VNDK-core: android.hardware.identity-V2-ndk_platform.so
-VNDK-core: android.hardware.identity-ndk_platform.so
 VNDK-core: android.hardware.keymaster-V2-ndk_platform.so
-VNDK-core: android.hardware.keymaster-ndk_platform.so
 VNDK-core: android.hardware.light-V1-ndk_platform.so
-VNDK-core: android.hardware.light-ndk_platform.so
 VNDK-core: android.hardware.media.bufferpool@2.0.so
 VNDK-core: android.hardware.media.omx@1.0.so
 VNDK-core: android.hardware.media@1.0.so
 VNDK-core: android.hardware.memtrack-V1-ndk_platform.so
-VNDK-core: android.hardware.memtrack-ndk_platform.so
-VNDK-core: android.hardware.memtrack-unstable-ndk_platform.so
 VNDK-core: android.hardware.memtrack@1.0.so
 VNDK-core: android.hardware.oemlock-V1-ndk_platform.so
-VNDK-core: android.hardware.oemlock-ndk_platform.so
-VNDK-core: android.hardware.oemlock-unstable-ndk_platform.so
 VNDK-core: android.hardware.power-V1-ndk_platform.so
-VNDK-core: android.hardware.power-ndk_platform.so
 VNDK-core: android.hardware.power.stats-V1-ndk_platform.so
-VNDK-core: android.hardware.power.stats-ndk_platform.so
-VNDK-core: android.hardware.power.stats-unstable-ndk_platform.so
 VNDK-core: android.hardware.rebootescrow-V1-ndk_platform.so
-VNDK-core: android.hardware.rebootescrow-ndk_platform.so
 VNDK-core: android.hardware.security.keymint-V1-ndk_platform.so
-VNDK-core: android.hardware.security.keymint-ndk_platform.so
-VNDK-core: android.hardware.security.keymint-unstable-ndk_platform.so
 VNDK-core: android.hardware.security.secureclock-V1-ndk_platform.so
-VNDK-core: android.hardware.security.secureclock-ndk_platform.so
-VNDK-core: android.hardware.security.secureclock-unstable-ndk_platform.so
 VNDK-core: android.hardware.security.sharedsecret-V1-ndk_platform.so
-VNDK-core: android.hardware.security.sharedsecret-ndk_platform.so
-VNDK-core: android.hardware.security.sharedsecret-unstable-ndk_platform.so
 VNDK-core: android.hardware.soundtrigger@2.0-core.so
 VNDK-core: android.hardware.soundtrigger@2.0.so
 VNDK-core: android.hardware.vibrator-V1-ndk_platform.so
-VNDK-core: android.hardware.vibrator-ndk_platform.so
 VNDK-core: android.hardware.weaver-V1-ndk_platform.so
-VNDK-core: android.hardware.weaver-ndk_platform.so
-VNDK-core: android.hardware.weaver-unstable-ndk_platform.so
 VNDK-core: android.hidl.token@1.0-utils.so
 VNDK-core: android.hidl.token@1.0.so
 VNDK-core: android.system.keystore2-V1-ndk_platform.so
-VNDK-core: android.system.keystore2-ndk_platform.so
-VNDK-core: android.system.keystore2-unstable-ndk_platform.so
 VNDK-core: android.system.suspend@1.0.so
 VNDK-core: libaudioroute.so
 VNDK-core: libaudioutils.so
diff --git a/tools/compare_builds.py b/tools/compare_builds.py
new file mode 100755
index 0000000..838a628
--- /dev/null
+++ b/tools/compare_builds.py
@@ -0,0 +1,661 @@
+#!/usr/bin/env -S python3 -u
+
+"""
+This script helps find various build behaviors that make builds less hermetic
+and repeatable. Depending on the flags, it runs a sequence of builds and looks
+for files that have changed or have been improperly regenerated, updating
+their timestamps incorrectly. It also looks for changes that the build has
+done to the source tree, and for files whose contents are dependent on the
+location of the out directory.
+
+This utility has two major modes, full and incremental. By default, this tool
+runs in full mode. To run in incremental mode, pass the --incremental flag.
+
+
+FULL MODE
+
+In full mode, this tool helps verify BUILD CORRECTNESS by examining its
+REPEATABILITY. In full mode, this tool runs two complete builds in different
+directories and compares the CONTENTS of the two directories. Lists of any
+files that are added, removed or changed are printed, sorted by the timestamp
+of that file, to aid finding which dependencies trigger the rebuilding of
+other files.
+
+
+INCREMENTAL MODE
+
+In incremental mode, this tool helps verfiy the SPEED of the build. It runs two
+builds and looks at the TIMESTAMPS of the generated files, and reports files
+that were changed by the second build. In theory, an incremental build with no
+source files touched should not have any generated targets changed. As in full
+builds, the file list is returned sorted by timestamp.
+
+
+OTHER CHECKS
+
+In both full and incremental mode, this tool looks at the timestamps of all
+source files in the tree, and reports on files that have been touched. In the
+output, these are labeled with the header "Source files touched after start of
+build."
+
+In addition, by default, this tool sets the OUT_DIR environment variable to
+something other than "out" in order to find build rules that are not respecting
+the OUT_DIR. If you see these, you should fix them, but if your build can not
+complete for some reason because of this, you can pass the --no-check-out-dir
+flag to suppress this check.
+
+
+OTHER FLAGS
+
+In full mode, the --detect-embedded-paths flag does the two builds in different
+directories, to help in finding rules that embed the out directory path into
+the targets.
+
+The --hide-build-output flag hides the output of successful bulds, to make
+script output cleaner. The output of builds that fail is still shown.
+
+The --no-build flag is useful if you have already done a build and would
+just like to re-run the analysis.
+
+The --target flag lets you specify a build target other than the default
+full build (droid). You can pass "nothing" as in the example below, or a
+specific target, to reduce the scope of the checks performed.
+
+The --touch flag lets you specify a list of source files to touch between
+the builds, to examine the consequences of editing a particular file.
+
+
+EXAMPLE COMMANDLINES
+
+Please run build/make/tools/compare_builds.py --help for a full listing
+of the commandline flags. Here are a sampling of useful combinations.
+
+  1. Find files changed during an incremental build that doesn't build
+     any targets.
+
+       build/make/tools/compare_builds.py --incremental --target nothing
+
+     Long incremental build times, or consecutive builds that re-run build actions
+     are usually caused by files being touched as part of loading the makefiles.
+
+     The nothing build (m nothing) loads the make and blueprint files, generates
+     the dependency graph, but then doesn't actually build any targets. Checking
+     against this build is the fastest and easiest way to find files that are
+     modified while makefiles are read, for example with $(shell) invocations.
+
+  2. Find packaging targets that are different, ignoring intermediate files.
+
+       build/make/tools/compare_builds.py --subdirs --detect-embedded-paths
+
+     These flags will compare the final staging directories for partitions,
+     as well as the APKs, apexes, testcases, and the like (the full directory
+     list is in the DEFAULT_DIRS variable below). Since these are the files
+     that are ultimately released, it is more important that these files be
+     replicable, even if the intermediates that went into them are not (for
+     example, when debugging symbols are stripped).
+
+  3. Check that all targets are repeatable.
+
+       build/make/tools/compare_builds.py --detect-embedded-paths
+
+     This check will list all of the differences in built targets that it can
+     find. Be aware that the AOSP tree still has quite a few targets that
+     are flagged by this check, so OEM changes might be lost in that list.
+     That said, each file shown here is a potential blocker for a repeatable
+     build.
+
+  4. See what targets are rebuilt when a file is touched between builds.
+
+       build/make/tools/compare_builds.py --incremental \
+            --touch frameworks/base/core/java/android/app/Activity.java
+
+     This check simulates the common engineer workflow of touching a single
+     file and rebuilding the whole system. To see a restricted view, consider
+     also passing a --target option for a common use case. For example:
+
+       build/make/tools/compare_builds.py --incremental --target framework \
+            --touch frameworks/base/core/java/android/app/Activity.java
+"""
+
+import argparse
+import itertools
+import os
+import shutil
+import stat
+import subprocess
+import sys
+
+
+# Soong
+SOONG_UI = "build/soong/soong_ui.bash"
+
+
+# Which directories to use if no --subdirs is supplied without explicit directories.
+DEFAULT_DIRS = (
+    "apex",
+    "data",
+    "product",
+    "ramdisk",
+    "recovery",
+    "root",
+    "system",
+    "system_ext",
+    "system_other",
+    "testcases",
+    "vendor",
+)
+
+
+# Files to skip for incremental timestamp checking
+BUILD_INTERNALS_PREFIX_SKIP = (
+    "soong/.glob/",
+    ".path/",
+)
+
+
+BUILD_INTERNALS_SUFFIX_SKIP = (
+    "/soong/soong_build_metrics.pb",
+    "/.installable_test_files",
+    "/files.db",
+    "/.blueprint.bootstrap",
+    "/build_number.txt",
+    "/build.ninja",
+    "/.out-dir",
+    "/build_fingerprint.txt",
+    "/build_thumbprint.txt",
+    "/.copied_headers_list",
+    "/.installable_files",
+)
+
+
+class DiffType(object):
+  def __init__(self, code, message):
+    self.code = code
+    self.message = message
+
+DIFF_NONE = DiffType("DIFF_NONE", "Files are the same")
+DIFF_MODE = DiffType("DIFF_MODE", "Stat mode bits differ")
+DIFF_SIZE = DiffType("DIFF_SIZE", "File size differs")
+DIFF_SYMLINK = DiffType("DIFF_SYMLINK", "Symlinks point to different locations")
+DIFF_CONTENTS = DiffType("DIFF_CONTENTS", "File contents differ")
+
+
+def main():
+  argparser = argparse.ArgumentParser(description="Diff build outputs from two builds.",
+                                      epilog="Run this command from the root of the tree."
+                                        + " Before running this command, the build environment"
+                                        + " must be set up, including sourcing build/envsetup.sh"
+                                        + " and running lunch.")
+  argparser.add_argument("--detect-embedded-paths", action="store_true",
+      help="Use unique out dirs to detect paths embedded in binaries.")
+  argparser.add_argument("--incremental", action="store_true",
+      help="Compare which files are touched in two consecutive builds without a clean in between.")
+  argparser.add_argument("--hide-build-output", action="store_true",
+      help="Don't print the build output for successful builds")
+  argparser.add_argument("--no-build", dest="run_build", action="store_false",
+      help="Don't build or clean, but do everything else.")
+  argparser.add_argument("--no-check-out-dir", dest="check_out_dir", action="store_false",
+      help="Don't check for rules not honoring movable out directories.")
+  argparser.add_argument("--subdirs", nargs="*",
+      help="Only scan these subdirs of $PRODUCT_OUT instead of the whole out directory."
+           + " The --subdirs argument with no listed directories will give a default list.")
+  argparser.add_argument("--target", default="droid",
+      help="Make target to run. The default is droid")
+  argparser.add_argument("--touch", nargs="+", default=[],
+      help="Files to touch between builds. Must pair with --incremental.")
+  args = argparser.parse_args(sys.argv[1:])
+
+  if args.detect_embedded_paths and args.incremental:
+    sys.stderr.write("Can't pass --detect-embedded-paths and --incremental together.\n")
+    sys.exit(1)
+  if args.detect_embedded_paths and not args.check_out_dir:
+    sys.stderr.write("Can't pass --detect-embedded-paths and --no-check-out-dir together.\n")
+    sys.exit(1)
+  if args.touch and not args.incremental:
+    sys.stderr.write("The --incremental flag is required if the --touch flag is passed.")
+    sys.exit(1)
+
+  AssertAtTop()
+  RequireEnvVar("TARGET_PRODUCT")
+  RequireEnvVar("TARGET_BUILD_VARIANT")
+
+  # Out dir file names:
+  #   - dir_prefix - The directory we'll put everything in (except for maybe the top level
+  #     out/ dir).
+  #   - *work_dir - The directory that we will build directly into. This is in dir_prefix
+  #     unless --no-check-out-dir is set.
+  #   - *out_dir - After building, if work_dir is different from out_dir, we move the out
+  #     directory to here so we can do the comparisions.
+  #   - timestamp_* - Files we touch so we know the various phases between the builds, so we
+  #     can compare timestamps of files.
+  if args.incremental:
+    dir_prefix = "out_incremental"
+    if args.check_out_dir:
+      first_work_dir = first_out_dir = dir_prefix + "/out"
+      second_work_dir = second_out_dir = dir_prefix + "/out"
+    else:
+      first_work_dir = first_out_dir = "out"
+      second_work_dir = second_out_dir = "out"
+  else:
+    dir_prefix = "out_full"
+    first_out_dir = dir_prefix + "/out_1"
+    second_out_dir = dir_prefix + "/out_2"
+    if not args.check_out_dir:
+      first_work_dir = second_work_dir = "out"
+    elif args.detect_embedded_paths:
+      first_work_dir = first_out_dir
+      second_work_dir = second_out_dir
+    else:
+      first_work_dir = dir_prefix + "/work"
+      second_work_dir = dir_prefix + "/work"
+  timestamp_start = dir_prefix + "/timestamp_start"
+  timestamp_between = dir_prefix + "/timestamp_between"
+  timestamp_end = dir_prefix + "/timestamp_end"
+
+  if args.run_build:
+    # Initial clean, if necessary
+    print("Cleaning " + dir_prefix + "/")
+    Clean(dir_prefix)
+    print("Cleaning out/")
+    Clean("out")
+    CreateEmptyFile(timestamp_start)
+    print("Running the first build in " + first_work_dir)
+    RunBuild(first_work_dir, first_out_dir, args.target, args.hide_build_output)
+    for f in args.touch:
+      print("Touching " + f)
+      TouchFile(f)
+    CreateEmptyFile(timestamp_between)
+    print("Running the second build in " + second_work_dir)
+    RunBuild(second_work_dir, second_out_dir, args.target, args.hide_build_output)
+    CreateEmptyFile(timestamp_end)
+    print("Done building")
+    print()
+
+  # Which out directories to scan
+  if args.subdirs is not None:
+    if args.subdirs:
+      subdirs = args.subdirs
+    else:
+      subdirs = DEFAULT_DIRS
+    first_files = ProductFiles(RequireBuildVar(first_out_dir, "PRODUCT_OUT"), subdirs)
+    second_files = ProductFiles(RequireBuildVar(second_out_dir, "PRODUCT_OUT"), subdirs)
+  else:
+    first_files = OutFiles(first_out_dir)
+    second_files = OutFiles(second_out_dir)
+
+  printer = Printer()
+
+  if args.incremental:
+    # Find files that were rebuilt unnecessarily
+    touched_incrementally = FindOutFilesTouchedAfter(first_files,
+                                                     GetFileTimestamp(timestamp_between))
+    printer.PrintList("Touched in incremental build", touched_incrementally)
+  else:
+    # Compare the two out dirs
+    added, removed, changed = DiffFileList(first_files, second_files)
+    printer.PrintList("Added", added)
+    printer.PrintList("Removed", removed)
+    printer.PrintList("Changed", changed, "%s %s")
+
+  # Find files in the source tree that were touched
+  touched_during = FindSourceFilesTouchedAfter(GetFileTimestamp(timestamp_start))
+  printer.PrintList("Source files touched after start of build", touched_during)
+
+  # Find files and dirs that were output to "out" and didn't respect $OUT_DIR
+  if args.check_out_dir:
+    bad_out_dir_contents = FindFilesAndDirectories("out")
+    printer.PrintList("Files and directories created by rules that didn't respect $OUT_DIR",
+                      bad_out_dir_contents)
+
+  # If we didn't find anything, print success message
+  if not printer.printed_anything:
+    print("No bad behaviors found.")
+
+
+def AssertAtTop():
+  """If the current directory is not the top of an android source tree, print an error
+     message and exit."""
+  if not os.access(SOONG_UI, os.X_OK):
+    sys.stderr.write("FAILED: Please run from the root of the tree.\n")
+    sys.exit(1)
+
+
+def RequireEnvVar(name):
+  """Gets an environment variable. If that fails, then print an error message and exit."""
+  result = os.environ.get(name)
+  if not result:
+    sys.stderr.write("error: Can't determine %s. Please run lunch first.\n" % name)
+    sys.exit(1)
+  return result
+
+
+def RunSoong(out_dir, args, capture_output):
+  env = dict(os.environ)
+  env["OUT_DIR"] = out_dir
+  args = [SOONG_UI,] + args
+  if capture_output:
+    proc = subprocess.Popen(args, env=env, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
+    combined_output, none = proc.communicate()
+    return proc.returncode, combined_output
+  else:
+    result = subprocess.run(args, env=env)
+    return result.returncode, None
+
+
+def GetBuildVar(out_dir, name):
+  """Gets a variable from the build system."""
+  returncode, output = RunSoong(out_dir, ["--dumpvar-mode", name], True)
+  if returncode != 0:
+    return None
+  else:
+    return output.decode("utf-8").strip()
+
+
+def RequireBuildVar(out_dir, name):
+  """Gets a variable from the builds system. If that fails, then print an error
+     message and exit."""
+  value = GetBuildVar(out_dir, name)
+  if not value:
+    sys.stderr.write("error: Can't determine %s. Please run lunch first.\n" % name)
+    sys.exit(1)
+  return value
+
+
+def Clean(directory):
+  """"Deletes the supplied directory."""
+  try:
+    shutil.rmtree(directory)
+  except FileNotFoundError:
+    pass
+
+
+def RunBuild(work_dir, out_dir, target, hide_build_output):
+  """Runs a build. If the build fails, prints a message and exits."""
+  returncode, output = RunSoong(work_dir,
+                    ["--build-mode", "--all-modules", "--dir=" + os.getcwd(), target],
+                    hide_build_output)
+  if work_dir != out_dir:
+    os.replace(work_dir, out_dir)
+  if returncode != 0:
+    if hide_build_output:
+      # The build output was hidden, so print it now for debugging
+      sys.stderr.buffer.write(output)
+    sys.stderr.write("FAILED: Build failed. Stopping.\n")
+    sys.exit(1)
+
+
+def DiffFileList(first_files, second_files):
+  """Examines the files.
+
+  Returns:
+    Filenames of files in first_filelist but not second_filelist (added files)
+    Filenames of files in second_filelist but not first_filelist (removed files)
+    2-Tuple of filenames for the files that are in both but are different (changed files)
+  """
+  # List of files, relative to their respective PRODUCT_OUT directories
+  first_filelist = sorted([x for x in first_files], key=lambda x: x[1])
+  second_filelist = sorted([x for x in second_files], key=lambda x: x[1])
+
+  added = []
+  removed = []
+  changed = []
+
+  first_index = 0
+  second_index = 0
+
+  while first_index < len(first_filelist) and second_index < len(second_filelist):
+    # Path relative to source root and path relative to PRODUCT_OUT
+    first_full_filename, first_relative_filename = first_filelist[first_index]
+    second_full_filename, second_relative_filename = second_filelist[second_index]
+
+    if first_relative_filename < second_relative_filename:
+      # Removed
+      removed.append(first_full_filename)
+      first_index += 1
+    elif first_relative_filename > second_relative_filename:
+      # Added
+      added.append(second_full_filename)
+      second_index += 1
+    else:
+      # Both present
+      diff_type = DiffFiles(first_full_filename, second_full_filename)
+      if diff_type != DIFF_NONE:
+        changed.append((first_full_filename, second_full_filename))
+      first_index += 1
+      second_index += 1
+
+  while first_index < len(first_filelist):
+    first_full_filename, first_relative_filename = first_filelist[first_index]
+    removed.append(first_full_filename)
+    first_index += 1
+
+  while second_index < len(second_filelist):
+    second_full_filename, second_relative_filename = second_filelist[second_index]
+    added.append(second_full_filename)
+    second_index += 1
+
+  return (SortByTimestamp(added),
+          SortByTimestamp(removed),
+          SortByTimestamp(changed, key=lambda item: item[1]))
+
+
+def FindOutFilesTouchedAfter(files, timestamp):
+  """Find files in the given file iterator that were touched after timestamp."""
+  result = []
+  for full, relative in files:
+    ts = GetFileTimestamp(full)
+    if ts > timestamp:
+      result.append(TouchedFile(full, ts))
+  return [f.filename for f in sorted(result, key=lambda f: f.timestamp)]
+
+
+def GetFileTimestamp(filename):
+  """Get timestamp for a file (just wraps stat)."""
+  st = os.stat(filename, follow_symlinks=False)
+  return st.st_mtime
+
+
+def SortByTimestamp(items, key=lambda item: item):
+  """Sort the list by timestamp of files.
+  Args:
+    items - the list of items to sort
+    key - a function to extract a filename from each element in items
+  """
+  return [x[0] for x in sorted([(item, GetFileTimestamp(key(item))) for item in items],
+                               key=lambda y: y[1])]
+
+
+def FindSourceFilesTouchedAfter(timestamp):
+  """Find files in the source tree that have changed after timestamp. Ignores
+  the out directory."""
+  result = []
+  for root, dirs, files in os.walk(".", followlinks=False):
+    if root == ".":
+      RemoveItemsFromList(dirs, (".repo", "out", "out_full", "out_incremental"))
+    for f in files:
+      full = os.path.sep.join((root, f))[2:]
+      ts = GetFileTimestamp(full)
+      if ts > timestamp:
+        result.append(TouchedFile(full, ts))
+  return [f.filename for f in sorted(result, key=lambda f: f.timestamp)]
+
+
+def FindFilesAndDirectories(directory):
+  """Finds all files and directories inside a directory."""
+  result = []
+  for root, dirs, files in os.walk(directory, followlinks=False):
+    result += [os.path.sep.join((root, x, "")) for x in dirs]
+    result += [os.path.sep.join((root, x)) for x in files]
+  return result
+
+
+def CreateEmptyFile(filename):
+  """Create an empty file with now as the timestamp at filename."""
+  try:
+    os.makedirs(os.path.dirname(filename))
+  except FileExistsError:
+    pass
+  open(filename, "w").close()
+  os.utime(filename)
+
+
+def TouchFile(filename):
+  os.utime(filename)
+
+
+def DiffFiles(first_filename, second_filename):
+  def AreFileContentsSame(remaining, first_filename, second_filename):
+    """Compare the file contents. They must be known to be the same size."""
+    CHUNK_SIZE = 32*1024
+    with open(first_filename, "rb") as first_file:
+      with open(second_filename, "rb") as second_file:
+        while remaining > 0:
+          size = min(CHUNK_SIZE, remaining)
+          if first_file.read(CHUNK_SIZE) != second_file.read(CHUNK_SIZE):
+            return False
+          remaining -= size
+        return True
+
+  first_stat = os.stat(first_filename, follow_symlinks=False)
+  second_stat = os.stat(first_filename, follow_symlinks=False)
+
+  # Mode bits
+  if first_stat.st_mode != second_stat.st_mode:
+    return DIFF_MODE
+
+  # File size
+  if first_stat.st_size != second_stat.st_size:
+    return DIFF_SIZE
+
+  # Contents
+  if stat.S_ISLNK(first_stat.st_mode):
+    if os.readlink(first_filename) != os.readlink(second_filename):
+      return DIFF_SYMLINK
+  elif stat.S_ISREG(first_stat.st_mode):
+    if not AreFileContentsSame(first_stat.st_size, first_filename, second_filename):
+      return DIFF_CONTENTS
+
+  return DIFF_NONE
+
+
+class FileIterator(object):
+  """Object that produces an iterator containing all files in a given directory.
+
+  Each iteration yields a tuple containing:
+
+  [0] (full) Path to file relative to source tree.
+  [1] (relative) Path to the file relative to the base directory given in the
+      constructor.
+  """
+
+  def __init__(self, base_dir):
+    self._base_dir = base_dir
+
+  def __iter__(self):
+    return self._Iterator(self, self._base_dir)
+
+  def ShouldIncludeFile(self, root, path):
+    return False
+
+  class _Iterator(object):
+    def __init__(self, parent, base_dir):
+      self._parent = parent
+      self._base_dir = base_dir
+      self._walker = os.walk(base_dir, followlinks=False)
+      self._current_index = 0
+      self._current_dir = []
+
+    def __iter__(self):
+      return self
+
+    def __next__(self):
+      # os.walk's iterator will eventually terminate by raising StopIteration
+      while True:
+        if self._current_index >= len(self._current_dir):
+          root, dirs, files = self._walker.__next__()
+          full_paths = [os.path.sep.join((root, f)) for f in files]
+          pairs = [(f, f[len(self._base_dir)+1:]) for f in full_paths]
+          self._current_dir = [(full, relative) for full, relative in pairs
+                               if self._parent.ShouldIncludeFile(root, relative)]
+          self._current_index = 0
+          if not self._current_dir:
+            continue
+        index = self._current_index
+        self._current_index += 1
+        return self._current_dir[index]
+
+
+class OutFiles(FileIterator):
+  """Object that produces an iterator containing all files in a given out directory,
+  except for files which are known to be touched as part of build setup.
+  """
+  def __init__(self, out_dir):
+    super().__init__(out_dir)
+    self._out_dir = out_dir
+
+  def ShouldIncludeFile(self, root, relative):
+    # Skip files in root, although note that this could actually skip
+    # files that are sadly generated directly into that directory.
+    if root == self._out_dir:
+      return False
+    # Skiplist
+    for skip in BUILD_INTERNALS_PREFIX_SKIP:
+      if relative.startswith(skip):
+        return False
+    for skip in BUILD_INTERNALS_SUFFIX_SKIP:
+      if relative.endswith(skip):
+        return False
+    return True
+
+
+class ProductFiles(FileIterator):
+  """Object that produces an iterator containing files in listed subdirectories of $PRODUCT_OUT.
+  """
+  def __init__(self, product_out, subdirs):
+    super().__init__(product_out)
+    self._subdirs = subdirs
+
+  def ShouldIncludeFile(self, root, relative):
+    for subdir in self._subdirs:
+      if relative.startswith(subdir):
+        return True
+    return False
+
+
+class TouchedFile(object):
+  """A file in the out directory with a timestamp."""
+  def __init__(self, filename, timestamp):
+    self.filename = filename
+    self.timestamp = timestamp
+
+
+def RemoveItemsFromList(haystack, needles):
+  for needle in needles:
+    try:
+      haystack.remove(needle)
+    except ValueError:
+      pass
+
+
+class Printer(object):
+  def __init__(self):
+    self.printed_anything = False
+
+  def PrintList(self, title, items, fmt="%s"):
+    if items:
+      if self.printed_anything:
+        sys.stdout.write("\n")
+      sys.stdout.write("%s:\n" % title)
+      for item in items:
+        sys.stdout.write("  %s\n" % fmt % item)
+      self.printed_anything = True
+
+
+if __name__ == "__main__":
+  try:
+    main()
+  except KeyboardInterrupt:
+    pass
+
+
+# vim: ts=2 sw=2 sts=2 nocindent
diff --git a/tools/exercise_compare_builds b/tools/exercise_compare_builds
new file mode 100755
index 0000000..38e8405
--- /dev/null
+++ b/tools/exercise_compare_builds
@@ -0,0 +1,66 @@
+#!/bin/bash
+# Tests for compare_builds.py
+# usage (from root of source tree):
+#   build/make/tools/exercise_compare_builds
+
+HIDE_BUILD_OUTPUT=--hide-build-output
+
+function run()
+{
+    echo
+    echo
+    echo ============================================================
+    echo $1
+    shift
+    echo ./build/make/tools/compare_builds.py $HIDE_BUILD_OUTPUT --target incidentd $@
+    echo ============================================================
+    time ./build/make/tools/compare_builds.py $HIDE_BUILD_OUTPUT --target incidentd $@
+}
+
+function run_tests()
+{
+    # These should error out
+
+    run "Incremental build,  Separate work dirs  (invalid flag combo, should error out)" \
+        --incremental --detect-embedded-paths
+    run "Use out/ as work dir, Separate work dirs  (invalid flag combo, should error out)" \
+        --no-check-out-dir --detect-embedded-paths
+
+    # Each grouping starts with a build, and the following ones use --no-build to save time
+
+    run "REBUILD: Full builds,  Same work dir,  Whole out dir"
+    run "Full builds,  Same work dir,  Default subdirs" \
+        --no-build --subdirs
+    run "Full builds,  Same work dir,  Only $PRODUCT_OUT/system" \
+        --no-build --subdirs system
+
+    run "REBUILD: Full builds,  Use out/ as work dir,  Whole out dir" \
+        --no-check-out-dir
+    run "Full builds,  Use out/ as work dir,  Default subdirs" \
+        --no-build --no-check-out-dir --subdirs
+    run "Full builds,  Use out/ as work dir,  Only $PRODUCT_OUT/system" \
+        --no-build --no-check-out-dir --subdirs system
+
+    run "REBUILD: Full builds,  Separate work dirs,  Whole out dir" \
+        --detect-embedded-paths
+    run "Full builds,  Separate work dirs,  Default subdirs" \
+        --no-build --detect-embedded-paths --subdirs
+    run "Full builds,  Separate work dirs,  Only $PRODUCT_OUT/system" \
+        --no-build --detect-embedded-paths --subdirs system
+
+    run "REBUILD: Incremental build,  Same work dir,  Whole out dir" \
+        --incremental
+    run "Incremental build,  Same work dir,  Default subdirs" \
+        --no-build --incremental --subdirs
+    run "Incremental build,  Same work dir,  Only $PRODUCT_OUT/system" \
+        --no-build --incremental --subdirs system
+
+    run "REBUILD: Incremental build,  Use out/ as work dir,  Whole out dir" \
+        --incremental --no-check-out-dir
+    run "Incremental build,  Use out/ as work dir,  Default subdirs" \
+        --no-build --incremental --no-check-out-dir --subdirs
+    run "Incremental build,  Use out/ as work dir,  Only $PRODUCT_OUT/system" \
+        --no-build --incremental --no-check-out-dir --subdirs system
+}
+
+time run_tests 2>&1 | tee exercise_compare_builds.txt
diff --git a/tools/product_config/inherit_tree.py b/tools/product_config/inherit_tree.py
new file mode 100755
index 0000000..ae8a275
--- /dev/null
+++ b/tools/product_config/inherit_tree.py
@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+
+#
+# Run from the root of the tree, after product-config has been run to see
+# the product inheritance hierarchy for the current lunch target.
+#
+
+import csv
+import sys
+
+def PrintNodes(graph, node, prefix):
+  sys.stdout.write("%s%s" % (prefix, node))
+  children = graph.get(node, [])
+  if children:
+    sys.stdout.write(" {\n")
+    for child in sorted(graph.get(node, [])):
+      PrintNodes(graph, child, prefix + "  ")
+    sys.stdout.write("%s}\n" % prefix);
+  else:
+    sys.stdout.write("\n")
+
+def main(argv):
+  if len(argv) != 2:
+    print("usage: inherit_tree.py out/$TARGET_PRODUCT-$TARGET_BUILD_VARIANT/dumpconfig.csv")
+    sys.exit(1)
+
+  root = None
+  graph = {}
+  with open(argv[1], newline='') as csvfile:
+    for line in csv.reader(csvfile):
+      if not root:
+        # Look for PRODUCTS
+        if len(line) < 3 or line[0] != "phase" or line[1] != "PRODUCTS":
+          continue
+        root = line[2]
+      else:
+        # Everything else
+        if len(line) < 3 or line[0] != "inherit":
+          continue
+        graph.setdefault(line[1], list()).append(line[2])
+
+  PrintNodes(graph, root, "")
+
+
+if __name__ == "__main__":
+  main(sys.argv)
+
+# vim: set expandtab ts=2 sw=2 sts=2:
+
diff --git a/tools/product_config/src/com/android/build/config/ConfigBase.java b/tools/product_config/src/com/android/build/config/ConfigBase.java
new file mode 100644
index 0000000..9a81011
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/ConfigBase.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.io.PrintStream;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * Common parts between MakeConfig and the to-be-added GenericConfig, BazelConfig and SoongConfig.
+ */
+public class ConfigBase {
+    protected String mPhase;
+    protected List<String> mRootNodes;
+
+    /**
+     * State of the make varaible environment from before the first config file.
+     */
+    protected Map<String, Str> mInitialVariables = new HashMap();
+
+    /**
+     * State of the make varaible environment from after the first config file.
+     */
+    protected Map<String, Str> mFinalVariables = new HashMap();
+
+
+    /**
+     * The variables that are handled specially.
+     */
+    protected final TreeMap<String, VarType> mProductVars = new TreeMap();
+
+    public void setPhase(String phase) {
+        mPhase = phase;
+    }
+
+    public String getPhase() {
+        return mPhase;
+    }
+
+    public void setRootNodes(List<String> filenames) {
+        mRootNodes = new ArrayList(filenames);
+    }
+
+    public List<String> getRootNodes() {
+        return mRootNodes;
+    }
+
+    public void addProductVar(String name, VarType type) {
+        mProductVars.put(name, type);
+    }
+
+    public TreeMap<String, VarType> getProductVars() {
+        return mProductVars;
+    }
+
+    public VarType getVarType(String name) {
+        final VarType t = mProductVars.get(name);
+        if (t != null) {
+            return t;
+        } else {
+            return VarType.UNKNOWN;
+        }
+    }
+
+    public boolean isProductVar(String name) {
+        return mProductVars.get(name) != null;
+    }
+
+    /**
+     * Return the state the make variable environment from before the first config file.
+     */
+    public Map<String, Str> getInitialVariables() {
+        return mInitialVariables;
+    }
+
+    /**
+     * Return the state the make variable environment from before the first config file.
+     */
+    public Map<String, Str> getFinalVariables() {
+        return mFinalVariables;
+    }
+
+    /**
+     * Copy common base class fields from that to this.
+     */
+    public void copyFrom(ConfigBase that) {
+        setPhase(that.getPhase());
+        setRootNodes(that.getRootNodes());
+        for (Map.Entry<String, VarType> entry: that.getProductVars().entrySet()) {
+            addProductVar(entry.getKey(), entry.getValue());
+        }
+        mInitialVariables = new HashMap(that.getInitialVariables());
+        mFinalVariables = new HashMap(that.getFinalVariables());
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/ConvertMakeToGenericConfig.java b/tools/product_config/src/com/android/build/config/ConvertMakeToGenericConfig.java
new file mode 100644
index 0000000..39bd5df
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/ConvertMakeToGenericConfig.java
@@ -0,0 +1,235 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Converts a MakeConfig into a Generic config by applying heuristics about
+ * the types of variable assignments that we do.
+ */
+public class ConvertMakeToGenericConfig {
+    private final Errors mErrors;
+
+    public ConvertMakeToGenericConfig(Errors errors) {
+        mErrors = errors;
+    }
+
+    public GenericConfig convert(Map<String, MakeConfig> make) {
+        final GenericConfig result = new GenericConfig();
+
+        final MakeConfig products = make.get("PRODUCTS");
+        if (products == null) {
+            mErrors.ERROR_DUMPCONFIG.add("Could not find PRODUCTS phase in dumpconfig output.");
+            return null;
+        }
+
+        // Base class fields
+        result.copyFrom(products);
+
+        // Each file
+        for (MakeConfig.ConfigFile f: products.getConfigFiles()) {
+            final GenericConfig.ConfigFile genericFile
+                    = new GenericConfig.ConfigFile(f.getFilename());
+            result.addConfigFile(genericFile);
+
+            final List<MakeConfig.Block> blocks = f.getBlocks();
+
+            // Some assertions:
+            // TODO: Include better context for these errors.
+            // There should always be at least a BEGIN and an AFTER, so assert this.
+            if (blocks.size() < 2) {
+                throw new RuntimeException("expected at least blocks.size() >= 2. Actcual size: "
+                        + blocks.size());
+            }
+            if (blocks.get(0).getBlockType() != MakeConfig.BlockType.BEFORE) {
+                throw new RuntimeException("expected first block to be BEFORE");
+            }
+            if (blocks.get(blocks.size() - 1).getBlockType() != MakeConfig.BlockType.AFTER) {
+                throw new RuntimeException("expected first block to be AFTER");
+            }
+            // Everything in between should be an INHERIT block.
+            for (int index = 1; index < blocks.size() - 1; index++) {
+                if (blocks.get(index).getBlockType() != MakeConfig.BlockType.INHERIT) {
+                    throw new RuntimeException("expected INHERIT at block " + index);
+                }
+            }
+
+            // Each block represents a snapshot of the interpreter variable state (minus a few big
+            // sets of variables which we don't export because they're used in the internals
+            // of node_fns.mk, so we know they're not necessary here). The first (BEFORE) one
+            // is everything that is set before the file is included, so it forms the base
+            // for everything else.
+            MakeConfig.Block prevBlock = blocks.get(0);
+
+            for (int index = 1; index < blocks.size(); index++) {
+                final MakeConfig.Block block = blocks.get(index);
+                for (final Map.Entry<String, Str> entry: block.getVars().entrySet()) {
+                    final String varName = entry.getKey();
+                    final GenericConfig.Assign assign = convertAssignment(block.getBlockType(),
+                            block.getInheritedFile(), products.getVarType(varName), varName,
+                            entry.getValue(), prevBlock.getVar(varName));
+                    if (assign != null) {
+                        genericFile.addStatement(assign);
+                    }
+                }
+                // Handle variables that are in prevBlock but not block -- they were
+                // deleted. Is this even possible, or do they show up as ""?  We will
+                // treat them as positive assigments to empty string
+                for (String prevName: prevBlock.getVars().keySet()) {
+                    if (!block.getVars().containsKey(prevName)) {
+                        genericFile.addStatement(
+                                new GenericConfig.Assign(prevName, new Str("")));
+                    }
+                }
+                if (block.getBlockType() == MakeConfig.BlockType.INHERIT) {
+                    genericFile.addStatement(
+                            new GenericConfig.Inherit(block.getInheritedFile()));
+                }
+                // For next iteration
+                prevBlock = block;
+            }
+        }
+
+        // Overwrite the final variables with the ones that come from the PRODUCTS-EXPAND phase.
+        // Drop the ones that were newly defined between the two phases, but leave values
+        // that were modified between.  We do need to reproduce that logic in this tool.
+        final MakeConfig expand = make.get("PRODUCT-EXPAND");
+        if (expand == null) {
+            mErrors.ERROR_DUMPCONFIG.add("Could not find PRODUCT-EXPAND phase in dumpconfig"
+                    + " output.");
+            return null;
+        }
+        final Map<String, Str> productsFinal = products.getFinalVariables();
+        final Map<String, Str> expandInitial = expand.getInitialVariables();
+        final Map<String, Str> expandFinal = expand.getFinalVariables();
+        final Map<String, Str> finalFinal = result.getFinalVariables();
+        finalFinal.clear();
+        for (Map.Entry<String, Str> var: expandFinal.entrySet()) {
+            final String varName = var.getKey();
+            if (expandInitial.containsKey(varName) && !productsFinal.containsKey(varName)) {
+                continue;
+            }
+            finalFinal.put(varName, var.getValue());
+        }
+
+        return result;
+    }
+
+    /**
+     * Converts one variable from a MakeConfig Block into a GenericConfig Assignment.
+     */
+    GenericConfig.Assign convertAssignment(MakeConfig.BlockType blockType, Str inheritedFile,
+            VarType varType, String varName, Str varVal, Str prevVal) {
+        if (prevVal == null) {
+            // New variable.
+            return new GenericConfig.Assign(varName, varVal);
+        } else if (!varVal.equals(prevVal)) {
+            // The value changed from the last block.
+            if (varVal.length() == 0) {
+                // It was set to empty
+                return new GenericConfig.Assign(varName, varVal);
+            } else {
+                // Product vars have the @inherit processing. Other vars we
+                // will just ignore and put in one section at the end, based
+                // on the difference between the BEFORE and AFTER blocks.
+                if (varType == VarType.UNKNOWN) {
+                    if (blockType == MakeConfig.BlockType.AFTER) {
+                        // For UNKNOWN variables, we don't worry about the
+                        // intermediate steps, just take the final value.
+                        return new GenericConfig.Assign(varName, varVal);
+                    } else {
+                        return null;
+                    }
+                } else {
+                    return convertInheritedVar(blockType, inheritedFile,
+                            varName, varVal, prevVal);
+                }
+            }
+        } else {
+            // Variable not touched
+            return null;
+        }
+    }
+
+    /**
+     * Handle the special inherited values, where the inherit-product puts in the
+     * @inherit:... markers, adding Statements to the ConfigFile.
+     */
+    GenericConfig.Assign convertInheritedVar(MakeConfig.BlockType blockType, Str inheritedFile,
+            String varName, Str varVal, Str prevVal) {
+        String varText = varVal.toString();
+        String prevText = prevVal.toString().trim();
+        if (blockType == MakeConfig.BlockType.INHERIT) {
+            // inherit-product appends @inherit:... so drop that.
+            final String marker = "@inherit:" + inheritedFile;
+            if (varText.endsWith(marker)) {
+                varText = varText.substring(0, varText.length() - marker.length()).trim();
+            } else {
+                mErrors.ERROR_IMPROPER_PRODUCT_VAR_MARKER.add(varVal.getPosition(),
+                        "Variable didn't end with marker \"" + marker + "\": " + varText);
+            }
+        }
+
+        if (!varText.equals(prevText)) {
+            // If the variable value was actually changed.
+            final ArrayList<String> words = split(varText, prevText);
+            if (words.size() == 0) {
+                // Pure Assignment, none of the previous value is present.
+                return new GenericConfig.Assign(varName, new Str(varVal.getPosition(), varText));
+            } else {
+                // Self referential value (prepend, append, both).
+                if (words.size() > 2) {
+                    // This is indicative of a construction that might not be quite
+                    // what we want.  The above code will do something that works if it was
+                    // of the form "VAR := a $(VAR) b $(VAR) c", but if the original code
+                    // something else this won't work. This doesn't happen in AOSP, but
+                    // it's a theoretically possibility, so someone might do it.
+                    mErrors.WARNING_VARIABLE_RECURSION.add(varVal.getPosition(),
+                            "Possible unsupported variable recursion: "
+                                + varName + " = " + varVal + " (prev=" + prevVal + ")");
+                }
+                return new GenericConfig.Assign(varName, Str.toList(varVal.getPosition(), words));
+            }
+        } else {
+            // Variable not touched
+            return null;
+        }
+    }
+
+    /**
+     * Split 'haystack' on occurrences of 'needle'. Trims each string of whitespace
+     * to preserve make list semantics.
+     */
+    private static ArrayList<String> split(String haystack, String needle) {
+        final ArrayList<String> result = new ArrayList();
+        final int needleLen = needle.length();
+        if (needleLen == 0) {
+            return result;
+        }
+        int start = 0;
+        int end;
+        while ((end = haystack.indexOf(needle, start)) >= 0) {
+            result.add(haystack.substring(start, end).trim());
+            start = end + needleLen;
+        }
+        result.add(haystack.substring(start).trim());
+        return result;
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/CsvParser.java b/tools/product_config/src/com/android/build/config/CsvParser.java
new file mode 100644
index 0000000..1c8b9c3
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/CsvParser.java
@@ -0,0 +1,242 @@
+
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.android.build.config;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A CSV parser.
+ */
+public class CsvParser {
+    /**
+     * Internal string buffer grows by this amount.
+     */
+    private static final int CHUNK_SIZE = 64 * 1024;
+
+    /**
+     * Error parsing.
+     */
+    public static class ParseException extends Exception {
+        private int mLine;
+        private int mColumn;
+
+        public ParseException(int line, int column, String message) {
+            super(message);
+            mLine = line;
+            mColumn = column;
+        }
+
+        /**
+         * Line number in source file.
+         */
+        public int getLine() {
+            return mLine;
+        }
+
+        /**
+         * Column in source file.
+         */
+        public int getColumn() {
+            return mColumn;
+        }
+    }
+
+    public static class Line {
+        private final int mLineNumber;
+        private final List<String> mFields;
+
+        Line(int lineno, List<String> fields) {
+            mLineNumber = lineno;
+            mFields = fields;
+        }
+
+        public int getLine() {
+            return mLineNumber;
+        }
+
+        public List<String> getFields() {
+            return mFields;
+        }
+    }
+
+    // Parser States
+    private static final int STATE_START_LINE = 0;
+    private static final int STATE_START_FIELD = 1;
+    private static final int STATE_INSIDE_QUOTED_FIELD = 2;
+    private static final int STATE_FIRST_QUOTATION_MARK = 3;
+    private static final int STATE_INSIDE_UNQUOTED_FIELD = 4;
+    private static final int STATE_DONE = 5;
+
+    // Parser Actions
+    private static final int ACTION_APPEND_CHAR = 1;
+    private static final int ACTION_FIELD_COMPLETE = 2;
+    private static final int ACTION_LINE_COMPLETE = 4;
+
+    /**
+     * Constructor.
+     */
+    private CsvParser() {
+    }
+
+    /**
+     * Reads CSV and returns a list of Line objects.
+     *
+     * Handles newlines inside fields quoted with double quotes (").
+     *
+     * Doesn't report blank lines, but does include empty fields.
+     */
+    public static List<Line> parse(Reader reader)
+            throws ParseException, IOException {
+        ArrayList<Line> result = new ArrayList();
+        int line = 1;
+        int column = 1;
+        int pos = 0;
+        char[] buf = new char[CHUNK_SIZE];
+        HashMap<String,String> stringPool = new HashMap();
+        ArrayList<String> fields = new ArrayList();
+
+        int state = STATE_START_LINE;
+        while (state != STATE_DONE) {
+            int c = reader.read();
+            int action = 0;
+
+            if (state == STATE_START_LINE) {
+                if (c <= 0) {
+                    // No data, skip ACTION_LINE_COMPLETE.
+                    state = STATE_DONE;
+                } else if (c == '"') {
+                    state = STATE_INSIDE_QUOTED_FIELD;
+                } else if (c == ',') {
+                    action = ACTION_FIELD_COMPLETE;
+                    state = STATE_START_FIELD;
+                } else if (c == '\n') {
+                    // Consume the newline, state stays STATE_START_LINE.
+                } else {
+                    action = ACTION_APPEND_CHAR;
+                    state = STATE_INSIDE_UNQUOTED_FIELD;
+                }
+            } else if (state == STATE_START_FIELD) {
+                if (c <= 0) {
+                    // Field will be empty
+                    action = ACTION_FIELD_COMPLETE | ACTION_LINE_COMPLETE;
+                    state = STATE_DONE;
+                } else if (c == '"') {
+                    state = STATE_INSIDE_QUOTED_FIELD;
+                } else if (c == ',') {
+                    action = ACTION_FIELD_COMPLETE;
+                    state = STATE_START_FIELD;
+                } else if (c == '\n') {
+                    action = ACTION_FIELD_COMPLETE | ACTION_LINE_COMPLETE;
+                    state = STATE_START_LINE;
+                } else {
+                    action = ACTION_APPEND_CHAR;
+                    state = STATE_INSIDE_UNQUOTED_FIELD;
+                }
+            } else if (state == STATE_INSIDE_QUOTED_FIELD) {
+                if (c <= 0) {
+                    throw new ParseException(line, column,
+                            "Bad input: End of input inside quoted field.");
+                } else if (c == '"') {
+                    state = STATE_FIRST_QUOTATION_MARK;
+                } else {
+                    action = ACTION_APPEND_CHAR;
+                }
+            } else if (state == STATE_FIRST_QUOTATION_MARK) {
+                if (c <= 0) {
+                    action = ACTION_FIELD_COMPLETE | ACTION_LINE_COMPLETE;
+                    state = STATE_DONE;
+                } else if (c == '"') {
+                    action = ACTION_APPEND_CHAR;
+                    state = STATE_INSIDE_QUOTED_FIELD;
+                } else if (c == ',') {
+                    action = ACTION_FIELD_COMPLETE;
+                    state = STATE_START_FIELD;
+                } else if (c == '\n') {
+                    action = ACTION_FIELD_COMPLETE | ACTION_LINE_COMPLETE;
+                    state = STATE_START_LINE;
+                } else {
+                    throw new ParseException(line, column,
+                            "Bad input: Character after field ended or unquoted '\"'.");
+                }
+            } else if (state == STATE_INSIDE_UNQUOTED_FIELD) {
+                if (c <= 0) {
+                    action = ACTION_FIELD_COMPLETE | ACTION_LINE_COMPLETE;
+                    state = STATE_DONE;
+                } else if (c == ',') {
+                    action = ACTION_FIELD_COMPLETE;
+                    state = STATE_START_FIELD;
+                } else if (c == '\n') {
+                    action = ACTION_FIELD_COMPLETE | ACTION_LINE_COMPLETE;
+                    state = STATE_START_LINE;
+                } else {
+                    action = ACTION_APPEND_CHAR;
+                }
+            }
+
+            if ((action & ACTION_APPEND_CHAR) != 0) {
+                // Reallocate buffer if necessary. Hopefully not often because CHUNK_SIZE is big.
+                if (pos >= buf.length) {
+                    char[] old = buf;
+                    buf = new char[old.length + CHUNK_SIZE];
+                    System.arraycopy(old, 0, buf, 0, old.length);
+                }
+                // Store the character
+                buf[pos] = (char)c;
+                pos++;
+            }
+            if ((action & ACTION_FIELD_COMPLETE) != 0) {
+                // A lot of the strings are duplicated, so pool them to reduce peak memory
+                // usage. This could be made slightly better by having a custom key class
+                // that does the lookup without making a new String that gets immediately
+                // thrown away.
+                String field = new String(buf, 0, pos);
+                final String cached = stringPool.get(field);
+                if (cached == null) {
+                    stringPool.put(field, field);
+                } else {
+                    field = cached;
+                }
+                fields.add(field);
+                pos = 0;
+            }
+            if ((action & ACTION_LINE_COMPLETE) != 0) {
+                // Only report lines with any contents
+                if (fields.size() > 0) {
+                    result.add(new Line(line, fields));
+                    fields = new ArrayList();
+                }
+            }
+
+            if (c == '\n') {
+                line++;
+                column = 1;
+            } else {
+                column++;
+            }
+        }
+
+        return result;
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/DumpConfigParser.java b/tools/product_config/src/com/android/build/config/DumpConfigParser.java
new file mode 100644
index 0000000..c4cd963
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/DumpConfigParser.java
@@ -0,0 +1,322 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.android.build.config;
+
+import java.io.IOException;
+import java.io.Reader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Map;
+import java.util.regex.Pattern;
+
+/**
+ * Parses the output of ckati building build/make/core/dumpconfig.mk.
+ *
+ * The format is as follows:
+ *   - All processed lines are colon (':') separated fields.
+ *   - Lines before the dumpconfig_version line are dropped for forward compatibility
+ *   - Lines where the first field is config_var describe variables declared in makefiles
+ *     (implemented by the dump-config-vals macro)
+ *          Field   Description
+ *          0       "config_var" row type
+ *          1       Product makefile being processed
+ *          2       The variable name
+ *          3       The value of the variable
+ *          4       The location of the variable, as best tracked by kati
+ */
+public class DumpConfigParser {
+    private static final boolean DEBUG = false;
+
+    private final Errors mErrors;
+    private final String mFilename;
+    private final Reader mReader;
+
+    private final Map<String,MakeConfig> mResults = new HashMap();
+
+    private static final Pattern LIST_SEPARATOR = Pattern.compile("\\s+");
+
+    /**
+     * Constructor.
+     */
+    private DumpConfigParser(Errors errors, String filename, Reader reader) {
+        mErrors = errors;
+        mFilename = filename;
+        mReader = reader;
+    }
+
+    /**
+     * Parse the text into a map of the phase names to MakeConfig objects.
+     */
+    public static Map<String,MakeConfig> parse(Errors errors, String filename, Reader reader)
+            throws CsvParser.ParseException, IOException {
+        DumpConfigParser parser = new DumpConfigParser(errors, filename, reader);
+        parser.parseImpl();
+        return parser.mResults;
+    }
+
+    /**
+     * Parse the input.
+     */
+    private void parseImpl() throws CsvParser.ParseException, IOException {
+        final List<CsvParser.Line> lines = CsvParser.parse(mReader);
+        final int lineCount = lines.size();
+        int index = 0;
+
+        int dumpconfigVersion = 0;
+
+        // Ignore lines until until we get a dumpconfig_version line for forward compatibility.
+        // In a previous life, this loop parsed from all of kati's stdout, not just the file
+        // that dumpconfig.mk writes, but it's harmless to leave this loop in.  It gives us a
+        // little bit of flexibility which we probably won't need anyway, this tool probably
+        // won't diverge from dumpconfig.mk anyway.
+        for (; index < lineCount; index++) {
+            final CsvParser.Line line = lines.get(index);
+            final List<String> fields = line.getFields();
+
+            if (matchLineType(line, "dumpconfig_version", 1)) {
+                try {
+                    dumpconfigVersion = Integer.parseInt(fields.get(1));
+                } catch (NumberFormatException ex) {
+                    mErrors.WARNING_DUMPCONFIG.add(
+                            new Position(mFilename, line.getLine()),
+                            "Couldn't parse dumpconfig_version: " + fields.get(1));
+                }
+                break;
+            }
+        }
+
+        // If we never saw dumpconfig_version, there's a problem with the command, so stop.
+        if (dumpconfigVersion == 0) {
+            mErrors.ERROR_DUMPCONFIG.fatal(
+                    new Position(mFilename),
+                    "Never saw a valid dumpconfig_version line.");
+        }
+
+        // Any lines before the start signal will be dropped. We create garbage objects
+        // here to avoid having to check for null everywhere.
+        MakeConfig makeConfig = new MakeConfig();
+        MakeConfig.ConfigFile configFile = new MakeConfig.ConfigFile("<ignored>");
+        MakeConfig.Block block = new MakeConfig.Block(MakeConfig.BlockType.UNSET);
+        Map<String, Str> initialVariables = new HashMap();
+        Map<String, Str> finalVariables = new HashMap();
+
+        // Number of "phases" we've seen so far.
+        for (; index < lineCount; index++) {
+            final CsvParser.Line line = lines.get(index);
+            final List<String> fields = line.getFields();
+            final String lineType = fields.get(0);
+
+            if (matchLineType(line, "phase", 2)) {
+                // Start the new one
+                makeConfig = new MakeConfig();
+                makeConfig.setPhase(fields.get(1));
+                makeConfig.setRootNodes(splitList(fields.get(2)));
+                // If there is a duplicate phase of the same name, continue parsing, but
+                // don't add it.  Emit a warning.
+                if (!mResults.containsKey(makeConfig.getPhase())) {
+                    mResults.put(makeConfig.getPhase(), makeConfig);
+                } else {
+                    mErrors.WARNING_DUMPCONFIG.add(
+                            new Position(mFilename, line.getLine()),
+                            "Duplicate phase: " + makeConfig.getPhase()
+                                + ". This one will be dropped.");
+                }
+                initialVariables = makeConfig.getInitialVariables();
+                finalVariables = makeConfig.getFinalVariables();
+
+                if (DEBUG) {
+                    System.out.println("PHASE:");
+                    System.out.println("  " + makeConfig.getPhase());
+                    System.out.println("  " + makeConfig.getRootNodes());
+                }
+            } else if (matchLineType(line, "var", 2)) {
+                final VarType type = "list".equals(fields.get(1)) ? VarType.LIST : VarType.SINGLE;
+                makeConfig.addProductVar(fields.get(2), type);
+
+                if (DEBUG) {
+                    System.out.println("  VAR: " + type + " " + fields.get(2));
+                }
+            } else if (matchLineType(line, "import", 1)) {
+                final List<String> importStack = splitList(fields.get(1));
+                if (importStack.size() == 0) {
+                    mErrors.WARNING_DUMPCONFIG.add(
+                            new Position(mFilename, line.getLine()),
+                            "'import' line with empty include stack.");
+                    continue;
+                }
+
+                // The beginning of importing a new file.
+                configFile = new MakeConfig.ConfigFile(importStack.get(0));
+                if (makeConfig.addConfigFile(configFile) != null) {
+                    mErrors.WARNING_DUMPCONFIG.add(
+                            new Position(mFilename, line.getLine()),
+                            "Duplicate file imported in section: " + configFile.getFilename());
+                }
+                // We expect a Variable block next.
+                block = new MakeConfig.Block(MakeConfig.BlockType.BEFORE);
+                configFile.addBlock(block);
+
+                if (DEBUG) {
+                    System.out.println("  IMPORT: " + configFile.getFilename());
+                }
+            } else if (matchLineType(line, "inherit", 2)) {
+                final String currentFile = fields.get(1);
+                final String inheritedFile = fields.get(2);
+                if (!configFile.getFilename().equals(currentFile)) {
+                    mErrors.WARNING_DUMPCONFIG.add(
+                            new Position(mFilename, line.getLine()),
+                            "Unexpected current file in 'inherit' line '" + currentFile
+                                + "' while processing '" + configFile.getFilename() + "'");
+                    continue;
+                }
+
+                // There is already a file in progress, so add another var block to that.
+                block = new MakeConfig.Block(MakeConfig.BlockType.INHERIT);
+                // TODO: Make dumpconfig.mk also output a Position for inherit-product
+                block.setInheritedFile(new Str(inheritedFile));
+                configFile.addBlock(block);
+
+                if (DEBUG) {
+                    System.out.println("  INHERIT: " + inheritedFile);
+                }
+            } else if (matchLineType(line, "imported", 1)) {
+                final List<String> importStack = splitList(fields.get(1));
+                if (importStack.size() == 0) {
+                    mErrors.WARNING_DUMPCONFIG.add(
+                            new Position(mFilename, line.getLine()),
+                            "'imported' line with empty include stack.");
+                    continue;
+                }
+                final String currentFile = importStack.get(0);
+                if (!configFile.getFilename().equals(currentFile)) {
+                    mErrors.WARNING_DUMPCONFIG.add(
+                            new Position(mFilename, line.getLine()),
+                            "Unexpected current file in 'imported' line '" + currentFile
+                                + "' while processing '" + configFile.getFilename() + "'");
+                    continue;
+                }
+
+                // There is already a file in progress, so add another var block to that.
+                // This will be the last one, but will check that after parsing.
+                block = new MakeConfig.Block(MakeConfig.BlockType.AFTER);
+                configFile.addBlock(block);
+
+                if (DEBUG) {
+                    System.out.println("  AFTER: " + currentFile);
+                }
+            } else if (matchLineType(line, "val", 5)) {
+                final String productMakefile = fields.get(1);
+                final String blockTypeString = fields.get(2);
+                final String varName = fields.get(3);
+                final String varValue = fields.get(4);
+                final Position pos = Position.parse(fields.get(5));
+                final Str str = new Str(pos, varValue);
+
+                if (blockTypeString.equals("initial")) {
+                    initialVariables.put(varName, str);
+                } else if (blockTypeString.equals("final")) {
+                    finalVariables.put(varName, str);
+                } else {
+                    if (!productMakefile.equals(configFile.getFilename())) {
+                        mErrors.WARNING_DUMPCONFIG.add(
+                                new Position(mFilename, line.getLine()),
+                                "Mismatched 'val' product makefile."
+                                    + " Expected: " + configFile.getFilename()
+                                    + " Saw: " + productMakefile);
+                        continue;
+                    }
+
+                    final MakeConfig.BlockType blockType = parseBlockType(line, blockTypeString);
+                    if (blockType == null) {
+                        continue;
+                    }
+                    if (blockType != block.getBlockType()) {
+                        mErrors.WARNING_DUMPCONFIG.add(
+                                new Position(mFilename, line.getLine()),
+                                "Mismatched 'val' block type."
+                                    + " Expected: " + block.getBlockType()
+                                    + " Saw: " + blockType);
+                    }
+
+                    // Add the variable to the block in progress
+                    block.addVar(varName, str);
+                }
+            } else {
+                if (DEBUG) {
+                    System.out.print("# ");
+                    for (int d = 0; d < fields.size(); d++) {
+                        System.out.print(fields.get(d));
+                        if (d != fields.size() - 1) {
+                            System.out.print(",");
+                        }
+                    }
+                    System.out.println();
+                }
+            }
+        }
+    }
+
+    /**
+     * Return true if the line type matches 'lineType' and there are at least 'fieldCount'
+     * fields (not including the first field which is the line type).
+     */
+    private boolean matchLineType(CsvParser.Line line, String lineType, int fieldCount) {
+        final List<String> fields = line.getFields();
+        if (!lineType.equals(fields.get(0))) {
+            return false;
+        }
+        if (fields.size() < (fieldCount + 1)) {
+            mErrors.WARNING_DUMPCONFIG.add(new Position(mFilename, line.getLine()),
+                    fields.get(0) + " line has " + fields.size() + " fields. Expected at least "
+                    + (fieldCount + 1) + " fields.");
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Split a string with space separated items (i.e. the make list format) into a List<String>.
+     */
+    private static List<String> splitList(String text) {
+        // Arrays.asList returns a fixed-length List, so we copy it into an ArrayList to not
+        // propagate that surprise detail downstream.
+        return new ArrayList(Arrays.asList(LIST_SEPARATOR.split(text.trim())));
+    }
+
+    /**
+     * Parse a BockType or issue a warning if it can't be parsed.
+     */
+    private MakeConfig.BlockType parseBlockType(CsvParser.Line line, String text) {
+        if ("before".equals(text)) {
+            return MakeConfig.BlockType.BEFORE;
+        } else if ("inherit".equals(text)) {
+            return MakeConfig.BlockType.INHERIT;
+        } else if ("after".equals(text)) {
+            return MakeConfig.BlockType.AFTER;
+        } else {
+            mErrors.WARNING_DUMPCONFIG.add(
+                    new Position(mFilename, line.getLine()),
+                    "Invalid block type: " + text);
+            return null;
+        }
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/ErrorReporter.java b/tools/product_config/src/com/android/build/config/ErrorReporter.java
index 5d87636..0a0c9f4 100644
--- a/tools/product_config/src/com/android/build/config/ErrorReporter.java
+++ b/tools/product_config/src/com/android/build/config/ErrorReporter.java
@@ -171,7 +171,7 @@
     /**
      * An instance of an error happening.
      */
-    public class Entry {
+    public static class Entry {
         private final Category mCategory;
         private final Position mPosition;
         private final String mMessage;
diff --git a/tools/product_config/src/com/android/build/config/Errors.java b/tools/product_config/src/com/android/build/config/Errors.java
index 63792c8..b333e78 100644
--- a/tools/product_config/src/com/android/build/config/Errors.java
+++ b/tools/product_config/src/com/android/build/config/Errors.java
@@ -30,7 +30,7 @@
  * <b>Naming Convention:</b>
  * <ul>
  *  <li>ERROR_ for Categories with isLevelSettable false and Level.ERROR
- *  <li>WARNING_ for Categories with isLevelSettable false and default WARNING or HIDDEN
+ *  <li>WARNING_ for Categories with isLevelSettable true and default WARNING or HIDDEN
  *  <li>Don't have isLevelSettable true and not ERROR. (The constructor asserts this).
  * </ul>
  */
@@ -42,4 +42,33 @@
     public final Category WARNING_UNKNOWN_COMMAND_LINE_ERROR = new Category(2, true, Level.HIDDEN,
             "Passing unknown errors on the command line.  Hidden by default for\n"
             + "forward compatibility.");
+
+    public final Category ERROR_KATI = new Category(3, false, Level.ERROR,
+            "Error executing or reading from Kati.");
+
+    public final Category WARNING_DUMPCONFIG = new Category(4, true, Level.WARNING,
+            "Anomaly parsing the output of kati and dumpconfig.mk.");
+
+    public final Category ERROR_DUMPCONFIG = new Category(5, false, Level.ERROR,
+            "Error parsing the output of kati and dumpconfig.mk.");
+
+    public final Category WARNING_VARIABLE_RECURSION = new Category(6, true, Level.WARNING,
+            "Possible unsupported variable recursion.");
+
+    // This could be a warning, but it's very likely that the data is corrupted somehow
+    // if we're seeing this.
+    public final Category ERROR_IMPROPER_PRODUCT_VAR_MARKER = new Category(7, true, Level.ERROR,
+            "Bad input from dumpvars causing corrupted product variables.");
+
+    public final Category ERROR_MISSING_CONFIG_FILE = new Category(8, true, Level.ERROR,
+            "Unable to find config file.");
+
+    public final Category ERROR_INFINITE_RECURSION = new Category(9, true, Level.ERROR,
+            "A file tries to inherit-product from itself or its own inherited products.");
+
+    // TODO: This will become obsolete when it is possible to have starlark-based product
+    // config files.
+    public final Category WARNING_DIFFERENT_FROM_KATI = new Category(1000, true, Level.WARNING,
+            "The cross-check with the original kati implementation failed.");
+
 }
diff --git a/tools/product_config/src/com/android/build/config/FlatConfig.java b/tools/product_config/src/com/android/build/config/FlatConfig.java
new file mode 100644
index 0000000..6f277fe
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/FlatConfig.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.io.PrintStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * Flattened configuration -- set of variables after all assignments and inherits have
+ * been executed.
+ */
+public class FlatConfig extends ConfigBase {
+
+    private final TreeMap<String, Value> mValues = new TreeMap();
+
+    public TreeMap<String, Value> getValues() {
+        return mValues;
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/FlattenConfig.java b/tools/product_config/src/com/android/build/config/FlattenConfig.java
new file mode 100644
index 0000000..a19802b
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/FlattenConfig.java
@@ -0,0 +1,474 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.TreeMap;
+import java.util.TreeSet;
+import java.util.regex.Pattern;
+
+public class FlattenConfig {
+    private static final Pattern RE_SPACE = Pattern.compile("\\p{Space}+");
+    private static final String PRODUCTS_PREFIX = "PRODUCTS";
+
+    private final Errors mErrors;
+    private final GenericConfig mGenericConfig;
+    private final Map<String, GenericConfig.ConfigFile> mGenericConfigs;
+    private final FlatConfig mResult = new FlatConfig();
+    private final Map<String, Value> mVariables;
+    /**
+     * Files that have been visited, to prevent infinite recursion. There are no
+     * conditionals at this point in the processing, so we don't need a stack, just
+     * a single set.
+     */
+    private final Set<Str> mStack = new HashSet();
+
+
+    private FlattenConfig(Errors errors, GenericConfig genericConfig) {
+        mErrors = errors;
+        mGenericConfig = genericConfig;
+        mGenericConfigs = genericConfig.getFiles();
+        mVariables = mResult.getValues();
+
+        // Base class fields
+        mResult.copyFrom(genericConfig);
+    }
+
+    /**
+     * Flatten a GenericConfig to a FlatConfig.
+     *
+     * Makes three passes through the genericConfig, one to flatten the single variables,
+     * one to flatten the list variables, and one to flatten the unknown variables. Each
+     * has a slightly different algorithm.
+     */
+    public static FlatConfig flatten(Errors errors, GenericConfig genericConfig) {
+        final FlattenConfig flattener = new FlattenConfig(errors, genericConfig);
+        return flattener.flattenImpl();
+    }
+
+    private FlatConfig flattenImpl() {
+        final List<String> rootNodes = mGenericConfig.getRootNodes();
+        if (rootNodes.size() == 0) {
+            mErrors.ERROR_DUMPCONFIG.add("No root nodes in PRODUCTS phase.");
+            return null;
+        } else if (rootNodes.size() != 1) {
+            final StringBuilder msg = new StringBuilder(
+                    "Ignoring extra root nodes in PRODUCTS phase. All nodes are:");
+            for (final String rn: rootNodes) {
+                msg.append(' ');
+                msg.append(rn);
+            }
+            mErrors.WARNING_DUMPCONFIG.add(msg.toString());
+        }
+        final String root = rootNodes.get(0);
+
+        // TODO: Do we need to worry about the initial state of variables? Anything
+        // that from the product config
+
+        flattenListVars(root);
+        flattenSingleVars(root);
+        flattenUnknownVars(root);
+        flattenInheritsFrom(root);
+
+        setDefaultKnownVars();
+
+        // TODO: This only supports the single product mode of import-nodes, which is all the
+        // real build does. m product-graph and friends will have to be rewritten.
+        mVariables.put("PRODUCTS", new Value(VarType.UNKNOWN, new Str(root)));
+
+        return mResult;
+    }
+
+    interface AssignCallback {
+        void onAssignStatement(GenericConfig.Assign assign);
+    }
+
+    interface InheritCallback {
+        void onInheritStatement(GenericConfig.Inherit assign);
+    }
+
+    /**
+     * Do a bunch of validity checks, and then iterate through each of the statements
+     * in the given file.  For Assignments, the callback is only called for variables
+     * matching varType.
+     *
+     * Adds makefiles which have been traversed to the 'seen' set, and will not traverse
+     * into an inherit statement if its makefile has already been seen.
+     */
+    private void forEachStatement(Str filename, VarType varType, Set<String> seen,
+            AssignCallback assigner, InheritCallback inheriter) {
+        if (mStack.contains(filename)) {
+            mErrors.ERROR_INFINITE_RECURSION.add(filename.getPosition(),
+                    "File is already in the inherit-product stack: " + filename);
+            return;
+        }
+
+        mStack.add(filename);
+        try {
+            final GenericConfig.ConfigFile genericFile = mGenericConfigs.get(filename.toString());
+
+            if (genericFile == null) {
+                mErrors.ERROR_MISSING_CONFIG_FILE.add(filename.getPosition(),
+                        "Unable to find config file: " + filename);
+                return;
+            }
+
+            for (final GenericConfig.Statement statement: genericFile.getStatements()) {
+                if (statement instanceof GenericConfig.Assign) {
+                    if (assigner != null) {
+                        final GenericConfig.Assign assign = (GenericConfig.Assign)statement;
+                        final String varName = assign.getName();
+
+                        // Assert that we're not stomping on another variable, which
+                        // really should be impossible at this point.
+                        assertVarType(filename, varName);
+
+                        if (mGenericConfig.getVarType(varName) == varType) {
+                            assigner.onAssignStatement(assign);
+                        }
+                    }
+                } else if (statement instanceof GenericConfig.Inherit) {
+                    if (inheriter != null) {
+                        final GenericConfig.Inherit inherit = (GenericConfig.Inherit)statement;
+                        if (seen != null) {
+                            if (seen.contains(inherit.getFilename().toString())) {
+                                continue;
+                            }
+                            seen.add(inherit.getFilename().toString());
+                        }
+                        inheriter.onInheritStatement(inherit);
+                    }
+                }
+            }
+        } finally {
+            // Also executes after return statements, so we always remove this.
+            mStack.remove(filename);
+        }
+    }
+
+    /**
+     * Call 'inheriter' for each child of 'filename' in alphabetical order.
+     */
+    private void forEachInheritAlpha(final Str filename, VarType varType, Set<String> seen,
+            InheritCallback inheriter) {
+        final TreeMap<Str, GenericConfig.Inherit> alpha = new TreeMap();
+        forEachStatement(filename, varType, null, null,
+                (inherit) -> {
+                    alpha.put(inherit.getFilename(), inherit);
+                });
+        for (final GenericConfig.Inherit inherit: alpha.values()) {
+            // Handle 'seen' here where we actaully call back, not before, so that
+            // the proper traversal order is preserved.
+            if (seen != null) {
+                if (seen.contains(inherit.getFilename().toString())) {
+                    continue;
+                }
+                seen.add(inherit.getFilename().toString());
+            }
+            inheriter.onInheritStatement(inherit);
+        }
+    }
+
+    /**
+     * Traverse the inheritance hierarchy, setting list-value product config variables.
+     */
+    private void flattenListVars(final String filename) {
+        Map<String, Value> vars = flattenListVars(new Str(filename), new HashSet());
+        // Add the result of the recursion to mVariables. We know there will be
+        // no collisions because this function only handles list variables.
+        for (Map.Entry<String, Value> entry: vars.entrySet()) {
+            mVariables.put(entry.getKey(), entry.getValue());
+        }
+    }
+
+    /**
+     * Return the variables defined, recursively, by 'filename.' The 'seen' set
+     * accumulates which nodes have been visited, as each is only done once.
+     *
+     * This convoluted algorithm isn't ideal, but it matches what is in node_fns.mk.
+     */
+    private Map<String, Value> flattenListVars(final Str filename, Set<String> seen) {
+        Map<String, Value> result = new HashMap();
+
+        // Recurse into our children first in alphabetical order, building a map of
+        // that filename to its flattened values.  The order matters here because
+        // we will only look at each child once, and when a file appears multiple
+        // times, its variables must have the right set, based on whether it's been
+        // seen before. This preserves the order from node_fns.mk.
+
+        // Child filename --> { varname --> value }
+        final Map<Str, Map<String, Value>> children = new HashMap();
+        forEachInheritAlpha(filename, VarType.LIST, seen,
+                (inherit) -> {
+                    final Str child = inherit.getFilename();
+                    children.put(child, flattenListVars(child, seen));
+                });
+
+        // Now, traverse the values again in the original source order to concatenate the values.
+        // Note that the contcatenation order is *different* from the inherit order above.
+        forEachStatement(filename, VarType.LIST, null,
+                (assign) -> {
+                    assignToListVar(result, assign.getName(), assign.getValue());
+                },
+                (inherit) -> {
+                    final Map<String, Value> child = children.get(inherit.getFilename());
+                    // child == null happens if this node has been visited before.
+                    if (child != null) {
+                        for (Map.Entry<String, Value> entry: child.entrySet()) {
+                            final String varName = entry.getKey();
+                            final Value varVal = entry.getValue();
+                            appendToListVar(result, varName, varVal.getList());
+                        }
+                    }
+                });
+
+        return result;
+    }
+
+    /**
+     * Traverse the inheritance hierarchy, setting single-value product config variables.
+     */
+    private void flattenSingleVars(final String filename) {
+        flattenSingleVars(new Str(filename), new HashSet(), new HashSet());
+    }
+
+    private void flattenSingleVars(final Str filename, Set<String> seen1, Set<String> seen2) {
+        // flattenSingleVars has two loops.  The first sets all variables that are
+        // defined for *this* file.  The second traverses through the inheritance,
+        // to fill in values that weren't defined in this file.  The first appearance of
+        // the variable is the one that wins.
+
+        forEachStatement(filename, VarType.SINGLE, seen1,
+                (assign) -> {
+                    final String varName = assign.getName();
+                    Value v = mVariables.get(varName);
+                    // Only take the first value that we see for single variables.
+                    Value value = mVariables.get(varName);
+                    if (!mVariables.containsKey(varName)) {
+                        final List<Str> valueList = assign.getValue();
+                        // There should never be more than one item in this list, because
+                        // SINGLE values should never be appended to.
+                        if (valueList.size() != 1) {
+                            final StringBuilder positions = new StringBuilder("[");
+                            for (Str s: valueList) {
+                                positions.append(s.getPosition());
+                            }
+                            positions.append(" ]");
+                            throw new RuntimeException("Value list found for SINGLE variable "
+                                    + varName + " size=" + valueList.size()
+                                    + "positions=" + positions.toString());
+                        }
+                        mVariables.put(varName,
+                                new Value(VarType.SINGLE,
+                                    valueList.get(0)));
+                    }
+                }, null);
+
+        forEachInheritAlpha(filename, VarType.SINGLE, seen2,
+                (inherit) -> {
+                    flattenSingleVars(inherit.getFilename(), seen1, seen2);
+                });
+    }
+
+    /**
+     * Traverse the inheritance hierarchy and flatten the values
+     */
+    private void flattenUnknownVars(String filename) {
+        flattenUnknownVars(new Str(filename), new HashSet());
+    }
+
+    private void flattenUnknownVars(final Str filename, Set<String> seen) {
+        // flattenUnknownVars has two loops: First to attempt to set the variable from
+        // this file, and then a second loop to handle the inheritance.  This is odd
+        // but it matches the order the files are included in node_fns.mk. The last appearance
+        // of the value is the one that wins.
+
+        forEachStatement(filename, VarType.UNKNOWN, null,
+                (assign) -> {
+                    // Overwrite the current value with whatever is now in the file.
+                    mVariables.put(assign.getName(),
+                            new Value(VarType.UNKNOWN,
+                                flattenAssignList(assign, new Str(""))));
+                }, null);
+
+        forEachInheritAlpha(filename, VarType.UNKNOWN, seen,
+                (inherit) -> {
+                    flattenUnknownVars(inherit.getFilename(), seen);
+                });
+    }
+
+    String prefix = "";
+
+    /**
+     * Sets the PRODUCTS.<filename>.INHERITS_FROM variables.
+     */
+    private void flattenInheritsFrom(final String filename) {
+        flattenInheritsFrom(new Str(filename));
+    }
+
+    /**
+     * This flatten function, unlike the others visits all of the nodes regardless
+     * of whether they have been seen before, because that's what the make code does.
+     */
+    private void flattenInheritsFrom(final Str filename) {
+        // Recurse, and gather the list our chlidren
+        final TreeSet<Str> children = new TreeSet();
+        forEachStatement(filename, VarType.LIST, null, null,
+                (inherit) -> {
+                    children.add(inherit.getFilename());
+                    flattenInheritsFrom(inherit.getFilename());
+                });
+
+        final String varName = "PRODUCTS." + filename + ".INHERITS_FROM";
+        if (children.size() > 0) {
+            // Build the space separated list.
+            boolean first = true;
+            final StringBuilder val = new StringBuilder();
+            for (Str child: children) {
+                if (first) {
+                    first = false;
+                } else {
+                    val.append(' ');
+                }
+                val.append(child);
+            }
+            mVariables.put(varName, new Value(VarType.UNKNOWN, new Str(val.toString())));
+        } else {
+            // Clear whatever flattenUnknownVars happened to have put in.
+            mVariables.remove(varName);
+        }
+    }
+
+    /**
+     * Throw an exception if there's an existing variable with a different type.
+     */
+    private void assertVarType(Str filename, String varName) {
+        if (mGenericConfig.getVarType(varName) == VarType.UNKNOWN) {
+            final Value prevValue = mVariables.get(varName);
+            if (prevValue != null
+                    && prevValue.getVarType() != VarType.UNKNOWN) {
+                throw new RuntimeException("Mismatched var types:"
+                        + " filename=" + filename
+                        + " varType=" + mGenericConfig.getVarType(varName)
+                        + " varName=" + varName
+                        + " prevValue=" + Value.debugString(prevValue));
+            }
+        }
+    }
+
+    /**
+     * Depending on whether the assignment is prepending, appending, setting, etc.,
+     * update the value.  We can infer which of those operations it is by the length
+     * and contents of the values. Each value in the list was originally separated
+     * by the previous value.
+     */
+    private void assignToListVar(Map<String, Value> vars, String varName, List<Str> items) {
+        final Value value = vars.get(varName);
+        final List<Str> orig = value == null ? new ArrayList() : value.getList();
+        final List<Str> result = new ArrayList();
+        if (items.size() > 0) {
+            for (int i = 0; i < items.size(); i++) {
+                if (i != 0) {
+                    result.addAll(orig);
+                }
+                final Str item = items.get(i);
+                addWords(result, item);
+            }
+        }
+        vars.put(varName, new Value(result));
+    }
+
+    /**
+     * Appends all of the words in in 'items' to an entry in vars keyed by 'varName',
+     * creating one if necessary.
+     */
+    private static void appendToListVar(Map<String, Value> vars, String varName, List<Str> items) {
+        Value value = vars.get(varName);
+        if (value == null) {
+            value = new Value(new ArrayList());
+            vars.put(varName, value);
+        }
+        final List<Str> out = value.getList();
+        for (Str item: items) {
+            addWords(out, item);
+        }
+    }
+
+    /**
+     * Split 'item' on spaces, and add each of them as a word to 'out'.
+     */
+    private static void addWords(List<Str> out, Str item) {
+        for (String word: RE_SPACE.split(item.toString().trim())) {
+            if (word.length() > 0) {
+                out.add(new Str(item.getPosition(), word));
+            }
+        }
+    }
+
+    /**
+     * Flatten the list of strings in an Assign statement, using the previous value
+     * as a separator.
+     */
+    private Str flattenAssignList(GenericConfig.Assign assign, Str previous) {
+        final StringBuilder result = new StringBuilder();
+        Position position = previous.getPosition();
+        final List<Str> list = assign.getValue();
+        final int size = list.size();
+        for (int i = 0; i < size; i++) {
+            final Str item = list.get(i);
+            result.append(item.toString());
+            if (i != size - 1) {
+                result.append(previous);
+            }
+            final Position pos = item.getPosition();
+            if (pos != null && pos.getFile() != null) {
+                position = pos;
+            }
+        }
+        return new Str(position, result.toString());
+    }
+
+    /**
+     * Make sure that each of the product config variables has a default value.
+     */
+    private void setDefaultKnownVars() {
+        for (Map.Entry<String, VarType> entry: mGenericConfig.getProductVars().entrySet()) {
+            final String varName = entry.getKey();
+            final VarType varType = entry.getValue();
+
+            final Value val = mVariables.get(varName);
+            if (val == null) {
+                mVariables.put(varName, new Value(varType));
+            }
+        }
+
+
+        // TODO: These two for now as well, until we can rewrite the enforce packages exist
+        // handling.
+        if (!mVariables.containsKey("PRODUCT_ENFORCE_PACKAGES_EXIST")) {
+            mVariables.put("PRODUCT_ENFORCE_PACKAGES_EXIST", new Value(VarType.UNKNOWN));
+        }
+        if (!mVariables.containsKey("PRODUCT_ENFORCE_PACKAGES_EXIST_ALLOW_LIST")) {
+            mVariables.put("PRODUCT_ENFORCE_PACKAGES_EXIST_ALLOW_LIST", new Value(VarType.UNKNOWN));
+        }
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/GenericConfig.java b/tools/product_config/src/com/android/build/config/GenericConfig.java
new file mode 100644
index 0000000..2ee2735
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/GenericConfig.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.io.PrintStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * Language-agnostic representation of a configuration statement.
+ */
+public class GenericConfig extends ConfigBase {
+    /**
+     * The config files that were imported in this config pass.
+     */
+    protected final TreeMap<String, ConfigFile> mConfigFiles = new TreeMap();
+
+    /**
+     * A configuration file.
+     */
+    public static class ConfigFile {
+        /**
+         * The name of the file, relative to the tree root.
+         */
+        private final String mFilename;
+
+        /**
+         * Sections of variable definitions and import statements. Product config
+         * files will always have at least one block.
+         */
+        private final ArrayList<Statement> mStatements = new ArrayList();
+
+        public ConfigFile(String filename) {
+            mFilename = filename;
+        }
+
+        public String getFilename() {
+            return mFilename;
+        }
+
+        public void addStatement(Statement statement) {
+            mStatements.add(statement);
+        }
+
+        public ArrayList<Statement> getStatements() {
+            return mStatements;
+        }
+    }
+
+    /**
+     * Base class for statements that appear in config files.
+     */
+    public static class Statement {
+    }
+
+    /**
+     * A variable assignment.
+     */
+    public static class Assign extends Statement {
+        private final String mVarName;
+        private final List<Str> mValue;
+
+        /**
+         * Assignment of a single value
+         */
+        public Assign(String varName, Str value) {
+            mVarName = varName;
+            mValue = new ArrayList();
+            mValue.add(value);
+        }
+
+        /**
+         * Assignment referencing a previous value.
+         *   VAR := $(1) $(VAR) $(2) $(VAR) $(3)
+         */
+        public Assign(String varName, List<Str> value) {
+            mVarName = varName;
+            mValue = value;
+        }
+
+        public String getName() {
+            return mVarName;
+        }
+
+        public List<Str> getValue() {
+            return mValue;
+        }
+    }
+
+    /**
+     * An $(inherit-product FILENAME) statement
+     */
+    public static class Inherit extends Statement {
+        private final Str mFilename;
+
+        public Inherit(Str filename) {
+            mFilename = filename;
+        }
+
+        public Str getFilename() {
+            return mFilename;
+        }
+    }
+
+    /**
+     * Adds the given config file. Returns any one previously added, or null.
+     */
+    public ConfigFile addConfigFile(ConfigFile file) {
+        return mConfigFiles.put(file.getFilename(), file);
+    }
+
+    public TreeMap<String, ConfigFile> getFiles() {
+        return mConfigFiles;
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/Kati.java b/tools/product_config/src/com/android/build/config/Kati.java
new file mode 100644
index 0000000..4fa2297
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/Kati.java
@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.util.Map;
+
+/**
+ * Wrapper for invoking kati.
+ */
+public interface Kati {
+    public Map<String, MakeConfig> loadProductConfig();
+}
diff --git a/tools/product_config/src/com/android/build/config/KatiCommand.java b/tools/product_config/src/com/android/build/config/KatiCommand.java
new file mode 100644
index 0000000..f3c71d2
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/KatiCommand.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.util.Arrays;
+import java.util.List;
+
+public interface KatiCommand {
+    public static class KatiException extends Exception {
+        private String mStderr;
+
+        public KatiException(List<String> cmd, String stderr) {
+            super("Error running kati: " + Arrays.toString(cmd.toArray()));
+            mStderr = stderr;
+        }
+
+        public String getStderr() {
+            return mStderr;
+        }
+    }
+
+    /**
+     * Run kati directly. Returns stdout data.
+     *
+     * @throws KatiException if there is an error. KatiException will contain
+     * the stderr from the kati invocation.
+     */
+    public String run(String[] args) throws KatiException;
+}
diff --git a/tools/product_config/src/com/android/build/config/KatiCommandImpl.java b/tools/product_config/src/com/android/build/config/KatiCommandImpl.java
new file mode 100644
index 0000000..53480d4
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/KatiCommandImpl.java
@@ -0,0 +1,139 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.nio.charset.StandardCharsets;
+
+public class KatiCommandImpl implements KatiCommand {
+    final Errors mErrors;
+    final Options mOptions;
+
+    /**
+     * Runnable that consumes all of an InputStream until EOF, writes the contents
+     * into a StringBuilder, and then closes the stream.
+     */
+    class OutputReader implements Runnable {
+        private final InputStream mStream;
+        private final StringBuilder mOutput;
+
+        OutputReader(InputStream stream, StringBuilder output) {
+            mStream = stream;
+            mOutput = output;
+        }
+
+        @Override
+        public void run() {
+            final char[] buf = new char[16*1024];
+            final InputStreamReader reader = new InputStreamReader(mStream, StandardCharsets.UTF_8);
+            try {
+                int amt;
+                while ((amt = reader.read(buf, 0, buf.length)) >= 0) {
+                    mOutput.append(buf, 0, amt);
+                }
+            } catch (IOException ex) {
+                mErrors.ERROR_KATI.add("Error reading from kati: " + ex.getMessage());
+            } finally {
+                try {
+                    reader.close();
+                } catch (IOException ex) {
+                    // Close doesn't throw
+                }
+            }
+        }
+    }
+
+    public KatiCommandImpl(Errors errors, Options options) {
+        mErrors = errors;
+        mOptions = options;
+    }
+
+    /**
+     * Run kati directly. Returns stdout data.
+     *
+     * @throws KatiException if there is an error. KatiException will contain
+     * the stderr from the kati invocation.
+     */
+    public String run(String[] args) throws KatiException {
+        final ArrayList<String> cmd = new ArrayList();
+        cmd.add(mOptions.getCKatiBin());
+        for (String arg: args) {
+            cmd.add(arg);
+        }
+
+        final ProcessBuilder builder = new ProcessBuilder(cmd);
+        builder.redirectOutput(ProcessBuilder.Redirect.PIPE);
+        builder.redirectError(ProcessBuilder.Redirect.PIPE);
+
+        Process process = null;
+
+        try {
+            process = builder.start();
+        } catch (IOException ex) {
+            throw new KatiException(cmd, "IOException running process: " + ex.getMessage());
+        }
+
+        final StringBuilder stdout = new StringBuilder();
+        final Thread stdoutThread = new Thread(new OutputReader(process.getInputStream(), stdout),
+                "kati_stdout_reader");
+        stdoutThread.start();
+
+        final StringBuilder stderr = new StringBuilder();
+        final Thread stderrThread = new Thread(new OutputReader(process.getErrorStream(), stderr),
+                "kati_stderr_reader");
+        stderrThread.start();
+
+        int returnCode = waitForProcess(process);
+        joinThread(stdoutThread);
+        joinThread(stderrThread);
+
+        if (returnCode != 0) {
+            throw new KatiException(cmd, stderr.toString());
+        }
+
+        return stdout.toString();
+    }
+
+    /**
+     * Wrap Process.waitFor() because it throws InterruptedException.
+     */
+    private static int waitForProcess(Process proc) {
+        while (true) {
+            try {
+                return proc.waitFor();
+            } catch (InterruptedException ex) {
+            }
+        }
+    }
+
+    /**
+     * Wrap Thread.join() because it throws InterruptedException.
+     */
+    private static void joinThread(Thread thread) {
+        while (true) {
+            try {
+                thread.join();
+                return;
+            } catch (InterruptedException ex) {
+            }
+        }
+    }
+}
+
diff --git a/tools/product_config/src/com/android/build/config/KatiImpl.java b/tools/product_config/src/com/android/build/config/KatiImpl.java
new file mode 100644
index 0000000..de11f36
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/KatiImpl.java
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class KatiImpl implements Kati {
+    // Subdirectory inside out for config stuff.
+    private static final String CONFIG_SUBDIR = "config";
+
+    private final Errors mErrors;
+    private final Options mOptions;
+    private final KatiCommand mCommand;
+
+    // TODO: Do we need to consider the whole or a greater subset of the
+    // environment (or a hash of it?). In theory product-variant is enough, but we know
+    // people use stuff from the environment, even though we're trying to get rid of that.
+    private String getWorkDirPath() {
+        return Paths.get(mOptions.getOutDir(), CONFIG_SUBDIR,
+                mOptions.getProduct() + '-' + mOptions.getVariant()).toString();
+    }
+
+    private String getDumpConfigCsvPath() {
+        return Paths.get(getWorkDirPath(), "dumpconfig.csv").toString();
+    }
+
+    public KatiImpl(Errors errors, Options options) {
+        this(errors, options, new KatiCommandImpl(errors, options));
+    }
+
+    // VisibleForTesting
+    public KatiImpl(Errors errors, Options options, KatiCommand command) {
+        mErrors = errors;
+        mOptions = options;
+        mCommand = command;
+    }
+
+    @Override
+    public Map<String, MakeConfig> loadProductConfig() {
+        final String csvPath = getDumpConfigCsvPath();
+        try {
+            File workDir = new File(getWorkDirPath());
+
+            if ((workDir.exists() && !workDir.isDirectory()) || !workDir.mkdirs()) {
+                mErrors.ERROR_KATI.add("Unable to create directory: " + workDir);
+                return null; // TODO: throw exception?
+            }
+
+            String out = mCommand.run(new String[] {
+                    "-f", "build/make/core/dumpconfig.mk",
+                    "DUMPCONFIG_FILE=" + csvPath
+                });
+
+            if (!out.contains("***DONE***")) {
+                mErrors.ERROR_KATI.add(
+                        "Unknown error with kati, but it didn't print ***DONE*** message");
+                return null; // TODO: throw exception?
+            }
+            // TODO: Check that output was good.
+        } catch (KatiCommand.KatiException ex) {
+            mErrors.ERROR_KATI.add("Error running kati:\n" + ex.getStderr());
+            return null;
+        }
+
+        if (!(new File(csvPath)).canRead()) {
+            mErrors.ERROR_KATI.add("Kati ran but did not create " + csvPath);
+            return null;
+        }
+
+        try (FileReader reader = new FileReader(csvPath)) {
+            Map<String, MakeConfig> makeConfigs = DumpConfigParser.parse(mErrors, csvPath, reader);
+
+            if (makeConfigs.size() == 0) {
+                // TODO: Issue error?
+                return null;
+            }
+
+            return makeConfigs;
+        } catch (CsvParser.ParseException ex) {
+            mErrors.ERROR_KATI.add(new Position(csvPath, ex.getLine()),
+                    "Unable to parse output of dumpconfig.mk: " + ex.getMessage());
+            return null; // TODO: throw exception?
+        } catch (IOException ex) {
+            System.out.println(ex);
+            mErrors.ERROR_KATI.add("Unable to read " + csvPath + ": " + ex.getMessage());
+            return null; // TODO: throw exception?
+        }
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/Main.java b/tools/product_config/src/com/android/build/config/Main.java
index b792193..5cec55e 100644
--- a/tools/product_config/src/com/android/build/config/Main.java
+++ b/tools/product_config/src/com/android/build/config/Main.java
@@ -16,6 +16,11 @@
 
 package com.android.build.config;
 
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.TreeSet;
+
 public class Main {
     private final Errors mErrors;
     private final Options mOptions;
@@ -26,11 +31,44 @@
     }
 
     void run() {
-        System.out.println("Hello World");
-
         // TODO: Check the build environment to make sure we're running in a real
         // build environment, e.g. actually inside a source tree, with TARGET_PRODUCT
         // and TARGET_BUILD_VARIANT defined, etc.
+        Kati kati = new KatiImpl(mErrors, mOptions);
+        Map<String, MakeConfig> makeConfigs = kati.loadProductConfig();
+        if (makeConfigs == null || mErrors.hadError()) {
+            return;
+        }
+        if (false) {
+            for (MakeConfig makeConfig: (new TreeMap<String, MakeConfig>(makeConfigs)).values()) {
+                System.out.println();
+                System.out.println("=======================================");
+                System.out.println("PRODUCT CONFIG FILES : " + makeConfig.getPhase());
+                System.out.println("=======================================");
+                makeConfig.printToStream(System.out);
+            }
+        }
+
+        ConvertMakeToGenericConfig m2g = new ConvertMakeToGenericConfig(mErrors);
+        GenericConfig generic = m2g.convert(makeConfigs);
+        if (false) {
+            System.out.println("======================");
+            System.out.println("REGENERATED MAKE FILES");
+            System.out.println("======================");
+            MakeWriter.write(System.out, generic, 0);
+        }
+
+        // TODO: Lookup shortened name as used in PRODUCT_NAME / TARGET_PRODUCT
+        FlatConfig flat = FlattenConfig.flatten(mErrors, generic);
+        if (false) {
+            System.out.println("=======================");
+            System.out.println("FLATTENED VARIABLE LIST");
+            System.out.println("=======================");
+            MakeWriter.write(System.out, flat, 0);
+        }
+
+        OutputChecker checker = new OutputChecker(flat);
+        checker.reportErrors(mErrors);
 
         // TODO: Run kati and extract the variables and convert all that into starlark files.
 
@@ -38,8 +76,6 @@
 
         // TODO: Get the variables that were defined in starlark and use that to write
         // out the make, soong and bazel input files.
-        mErrors.ERROR_COMMAND_LINE.add("asdf");
-        throw new RuntimeException("poop");
     }
 
     public static void main(String[] args) {
@@ -47,7 +83,7 @@
         int exitCode = 0;
 
         try {
-            Options options = Options.parse(errors, args);
+            Options options = Options.parse(errors, args, System.getenv());
             if (errors.hadError()) {
                 Options.printHelp(System.err);
                 System.err.println();
@@ -62,7 +98,7 @@
                     Options.printHelp(System.out);
                     return;
             }
-        } catch (CommandException ex) {
+        } catch (CommandException | Errors.FatalException ex) {
             // These are user errors, so don't show a stack trace
             exitCode = 1;
         } catch (Throwable ex) {
@@ -76,7 +112,10 @@
         } finally {
             // Print errors and warnings
             errors.printErrors(System.err);
+            if (errors.hadError()) {
+                exitCode = 1;
+            }
+            System.exit(exitCode);
         }
-        System.exit(exitCode);
     }
 }
diff --git a/tools/product_config/src/com/android/build/config/MakeConfig.java b/tools/product_config/src/com/android/build/config/MakeConfig.java
new file mode 100644
index 0000000..dda0db9
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/MakeConfig.java
@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.io.PrintStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+public class MakeConfig extends ConfigBase {
+    /**
+     * The config files that were imported in this config pass.
+     */
+    protected final ArrayList<ConfigFile> mConfigFiles = new ArrayList();
+
+    public enum BlockType {
+        UNSET,
+        BEFORE,
+        INHERIT,
+        AFTER
+    }
+
+    public static class ConfigFile {
+        /**
+         * The name of the file, relative to the tree root.
+         */
+        private final String mFilename;
+
+        /**
+         * Sections of variable definitions and import statements. Product config
+         * files will always have at least one block.
+         */
+        private final ArrayList<Block> mBlocks = new ArrayList();
+
+        public ConfigFile(String filename) {
+            mFilename = filename;
+        }
+
+        public String getFilename() {
+            return mFilename;
+        }
+
+        public void addBlock(Block block) {
+            mBlocks.add(block);
+        }
+
+        public ArrayList<Block> getBlocks() {
+            return mBlocks;
+        }
+    }
+
+    /**
+     * A set of variables that were defined.
+     */
+    public static class Block {
+        private final BlockType mBlockType;
+        private final TreeMap<String, Str> mValues = new TreeMap();
+        private Str mInheritedFile;
+
+        public Block(BlockType blockType) {
+            mBlockType = blockType;
+        }
+
+        public BlockType getBlockType() {
+            return mBlockType;
+        }
+
+        public void addVar(String varName, Str varValue) {
+            mValues.put(varName, varValue);
+        }
+
+        public Str getVar(String varName) {
+            return mValues.get(varName);
+        }
+
+        public TreeMap<String, Str> getVars() {
+            return mValues;
+        }
+
+        public void setInheritedFile(Str filename) {
+            mInheritedFile = filename;
+        }
+
+        public Str getInheritedFile() {
+            return mInheritedFile;
+        }
+    }
+
+    /**
+     * Adds the given config file. Returns any one previously added, or null.
+     */
+    public ConfigFile addConfigFile(ConfigFile file) {
+        ConfigFile prev = null;
+        for (ConfigFile f: mConfigFiles) {
+            if (f.getFilename().equals(file.getFilename())) {
+                prev = f;
+                break;
+            }
+        }
+        mConfigFiles.add(file);
+        return prev;
+    }
+
+    public List<ConfigFile> getConfigFiles() {
+        return mConfigFiles;
+    }
+
+    public void printToStream(PrintStream out) {
+        out.println("MakeConfig {");
+        out.println("  phase: " + mPhase);
+        out.println("  rootNodes: " + mRootNodes);
+        out.print("  singleVars: [ ");
+        for (Map.Entry<String,VarType> entry: mProductVars.entrySet()) {
+            if (entry.getValue() == VarType.SINGLE) {
+                out.print(entry.getKey());
+                out.print(" ");
+            }
+        }
+        out.println("]");
+        out.print("  listVars: [ ");
+        for (Map.Entry<String,VarType> entry: mProductVars.entrySet()) {
+            if (entry.getValue() == VarType.LIST) {
+                out.print(entry.getKey());
+                out.print(" ");
+            }
+        }
+        out.println("]");
+        out.println("  configFiles: [");
+        for (final ConfigFile configFile: mConfigFiles) {
+            out.println("    ConfigFile {");
+            out.println("      filename: " + configFile.getFilename());
+            out.println("      blocks: [");
+            for (Block block: configFile.getBlocks()) {
+                out.println("        Block {");
+                out.println("          type: " + block.getBlockType());
+                if (block.getBlockType() == BlockType.INHERIT) {
+                    out.println("          inherited: " + block.getInheritedFile());
+                }
+                out.println("          values: {");
+                for (Map.Entry<String,Str> var: block.getVars().entrySet()) {
+                    if (!var.getKey().equals("PRODUCT_PACKAGES")) {
+                        continue;
+                    }
+                    out.println("            " + var.getKey() + ": " + var.getValue());
+                }
+                out.println("          }");
+                out.println("        }");
+            }
+            out.println("      ]");
+            out.println("    }");
+        }
+        out.println("  ] // configFiles");
+        out.println("} // MakeConfig");
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/MakeWriter.java b/tools/product_config/src/com/android/build/config/MakeWriter.java
new file mode 100644
index 0000000..15fd095
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/MakeWriter.java
@@ -0,0 +1,161 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.io.PrintStream;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+public class MakeWriter {
+    public static final int FLAG_WRITE_HEADER = 1;
+    public static final int FLAG_WRITE_ANNOTATIONS = 1 << 1;
+
+    private final boolean mWriteHeader;
+    private final boolean mWriteAnnotations;
+
+    public static void write(PrintStream out, GenericConfig config, int flags) {
+        (new MakeWriter(flags)).writeGeneric(out, config);
+    }
+
+    public static void write(PrintStream out, FlatConfig config, int flags) {
+        (new MakeWriter(flags)).writeFlat(out, config);
+    }
+
+
+    private MakeWriter(int flags) {
+        mWriteHeader = (flags & FLAG_WRITE_HEADER) != 0;
+        mWriteAnnotations = (flags & FLAG_WRITE_ANNOTATIONS) != 0;
+    }
+
+    private void writeGeneric(PrintStream out, GenericConfig config) {
+        for (GenericConfig.ConfigFile file: config.getFiles().values()) {
+            out.println("---------------------------------------------------------");
+            out.println("FILE: " + file.getFilename());
+            out.println("---------------------------------------------------------");
+            writeFile(out, config, file);
+            out.println();
+        }
+        out.println("---------------------------------------------------------");
+        out.println("VARIABLES TOUCHED BY MAKE BASED CONFIG:");
+        out.println("---------------------------------------------------------");
+        writeStrVars(out, OutputChecker.getModifiedVars(config.getInitialVariables(),
+                                          config.getFinalVariables()), config);
+    }
+
+    private void writeFile(PrintStream out, GenericConfig config, GenericConfig.ConfigFile file) {
+        if (mWriteHeader) {
+            out.println("# This file is generated by the product_config tool");
+        }
+        for (GenericConfig.Statement statement: file.getStatements()) {
+            if (statement instanceof GenericConfig.Assign) {
+                writeAssign(out, config, (GenericConfig.Assign)statement);
+            } else if (statement instanceof GenericConfig.Inherit) {
+                writeInherit(out, (GenericConfig.Inherit)statement);
+            } else {
+                throw new RuntimeException("Unexpected Statement: " + statement);
+            }
+        }
+    }
+
+    private void writeAssign(PrintStream out, GenericConfig config,
+            GenericConfig.Assign statement) {
+        final List<Str> values = statement.getValue();
+        final int size = values.size();
+        final String varName = statement.getName();
+        Position pos = null;
+        if (size == 0) {
+            return;
+        } else if (size == 1) {
+            // Plain :=
+            final Str value = values.get(0);
+            out.print(varName + " := " + value);
+            pos = value.getPosition();
+        } else if (size == 2 && values.get(0).toString().length() == 0) {
+            // Plain +=
+            final Str value = values.get(1);
+            out.print(varName + " += " + value);
+            pos = value.getPosition();
+        } else {
+            // Write it out the long way
+            out.print(varName + " := " + values.get(0));
+            for (int i = 1; i < size; i++) {
+                out.print("$(" + varName + ") " + values.get(i));
+                pos = values.get(i).getPosition();
+            }
+        }
+        if (mWriteAnnotations) {
+            out.print("  # " + config.getVarType(varName) + " " + pos);
+        }
+        out.println();
+    }
+
+    private void writeInherit(PrintStream out, GenericConfig.Inherit statement) {
+        final Str filename = statement.getFilename();
+        out.print("$(call inherit-product " + filename + ")");
+        if (mWriteAnnotations) {
+            out.print("  # " + filename.getPosition());
+        }
+        out.println();
+    }
+
+    private static class Var {
+        Var(String name, Str val) {
+            this.name = name;
+            this.val = val;
+        }
+        final String name;
+        final Str val;
+    }
+
+    private static void writeStrVars(PrintStream out, Map<String, Str> vars, ConfigBase config) {
+        // Sort by file name and var name
+        TreeMap<String, Var> sorted = new TreeMap();
+        for (Map.Entry<String, Str> entry: vars.entrySet()) {
+            sorted.put(entry.getValue().getPosition().toString() + " " + entry.getKey(),
+                    new Var(entry.getKey(), entry.getValue()));
+        }
+        // Print it
+        for (Var var: sorted.values()) {
+            out.println(var.val.getPosition() + var.name + " := " + var.val);
+        }
+    }
+
+    private void writeFlat(PrintStream out, FlatConfig config) {
+        // TODO: Print positions.
+        for (Map.Entry<String, Value> entry: config.getValues().entrySet()) {
+            out.print(entry.getKey());
+            out.print(" := ");
+
+            final Value value = entry.getValue();
+            if (value.getVarType() == VarType.LIST) {
+                final List<Str> list = value.getList();
+                final int size = list.size();
+                for (int i = 0; i < size; i++) {
+                    out.print(list.get(i).toString());
+                    if (i != size - 1) {
+                        out.print(" \\\n        ");
+                    }
+                }
+            } else {
+                out.print(value.getStr().toString());
+            }
+            out.println();
+        }
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/Options.java b/tools/product_config/src/com/android/build/config/Options.java
index 48146cb..ed544dc 100644
--- a/tools/product_config/src/com/android/build/config/Options.java
+++ b/tools/product_config/src/com/android/build/config/Options.java
@@ -17,6 +17,7 @@
 package com.android.build.config;
 
 import java.io.PrintStream;
+import java.util.Map;
 import java.util.TreeMap;
 
 public class Options {
@@ -27,19 +28,50 @@
 
     private Action mAction = Action.DEFAULT;
 
+    private String mProduct;
+    private String mVariant;
+    private String mOutDir;
+    private String mCKatiBin;
+
     public Action getAction() {
         return mAction;
     }
 
+    public String getProduct() {
+        return mProduct;
+    }
+
+    public String getVariant() {
+        return mVariant;
+    }
+
+    public String getOutDir() {
+        return mOutDir != null ? mOutDir : "out";
+    }
+
+    public String getCKatiBin() {
+        return mCKatiBin;
+    }
+
     public static void printHelp(PrintStream out) {
         out.println("usage: product_config");
         out.println();
-        out.println("OPTIONS");
+        out.println("REQUIRED FLAGS");
+        out.println("  --ckati_bin CKATI        Kati binary to use.");
+        out.println();
+        out.println("OPTIONAL FLAGS");
         out.println("  --hide ERROR_ID          Suppress this error.");
         out.println("  --error ERROR_ID         Make this ERROR_ID a fatal error.");
         out.println("  --help -h                This message.");
         out.println("  --warning ERROR_ID       Make this ERROR_ID a warning.");
         out.println();
+        out.println("REQUIRED ENVIRONMENT");
+        out.println("  TARGET_PRODUCT           Product to build from lunch command.");
+        out.println("  TARGET_BUILD_VARIANT     Build variant from lunch command.");
+        out.println();
+        out.println("OPTIONAL ENVIRONMENT");
+        out.println("  OUT_DIR                  Build output directory. Defaults to \"out\".");
+        out.println();
         out.println("ERRORS");
         out.println("  The following are the errors that can be controlled on the");
         out.println("  commandline with the --hide --warning --error flags.");
@@ -55,7 +87,7 @@
     }
 
     static class Parser {
-        private class ParseException extends Exception {
+        private static class ParseException extends Exception {
             public ParseException(String message) {
                 super(message);
             }
@@ -63,20 +95,26 @@
 
         private Errors mErrors;
         private String[] mArgs;
+        private Map<String,String> mEnv;
         private Options mResult = new Options();
         private int mIndex;
+        private boolean mSkipRequiredArgValidation;
 
-        public Parser(Errors errors, String[] args) {
+        public Parser(Errors errors, String[] args, Map<String,String> env) {
             mErrors = errors;
             mArgs = args;
+            mEnv = env;
         }
 
         public Options parse() {
+            // Args
             try {
                 while (mIndex < mArgs.length) {
                     final String arg = mArgs[mIndex];
 
-                    if ("--hide".equals(arg)) {
+                    if ("--ckati_bin".equals(arg)) {
+                        mResult.mCKatiBin = requireNextStringArg(arg);
+                    } else if ("--hide".equals(arg)) {
                         handleErrorCode(arg, Errors.Level.HIDDEN);
                     } else if ("--error".equals(arg)) {
                         handleErrorCode(arg, Errors.Level.ERROR);
@@ -99,11 +137,45 @@
                 mErrors.ERROR_COMMAND_LINE.add(ex.getMessage());
             }
 
+            // Environment
+            mResult.mProduct = mEnv.get("TARGET_PRODUCT");
+            mResult.mVariant = mEnv.get("TARGET_BUILD_VARIANT");
+            mResult.mOutDir = mEnv.get("OUT_DIR");
+
+            validateArgs();
+
             return mResult;
         }
 
-        private void addWarning(Errors.Category category, String message) {
-            category.add(message);
+        /**
+         * For testing; don't generate errors about missing arguments
+         */
+        public void setSkipRequiredArgValidation() {
+            mSkipRequiredArgValidation = true;
+        }
+
+        private void validateArgs() {
+            if (!mSkipRequiredArgValidation) {
+                if (mResult.mCKatiBin == null || "".equals(mResult.mCKatiBin)) {
+                    addMissingArgError("--ckati_bin");
+                }
+                if (mResult.mProduct == null) {
+                    addMissingEnvError("TARGET_PRODUCT");
+                }
+                if (mResult.mVariant == null) {
+                    addMissingEnvError("TARGET_BUILD_VARIANT");
+                }
+            }
+        }
+
+        private void addMissingArgError(String argName) {
+            mErrors.ERROR_COMMAND_LINE.add("Required command line argument missing: "
+                    + argName);
+        }
+
+        private void addMissingEnvError(String envName) {
+            mErrors.ERROR_COMMAND_LINE.add("Required environment variable missing: "
+                    + envName);
         }
 
         private String getNextNonFlagArg() {
@@ -117,6 +189,14 @@
             return mArgs[mIndex];
         }
 
+        private String requireNextStringArg(String arg) throws ParseException {
+            final String val = getNextNonFlagArg();
+            if (val == null) {
+                throw new ParseException(arg + " requires a string argument.");
+            }
+            return val;
+        }
+
         private int requireNextNumberArg(String arg) throws ParseException {
             final String val = getNextNonFlagArg();
             if (val == null) {
@@ -151,7 +231,7 @@
      * <p>
      * Adds errors encountered to Errors object.
      */
-    public static Options parse(Errors errors, String[] args) {
-        return (new Parser(errors, args)).parse();
+    public static Options parse(Errors errors, String[] args, Map<String, String> env) {
+        return (new Parser(errors, args, env)).parse();
     }
 }
diff --git a/tools/product_config/src/com/android/build/config/OutputChecker.java b/tools/product_config/src/com/android/build/config/OutputChecker.java
new file mode 100644
index 0000000..d982dba
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/OutputChecker.java
@@ -0,0 +1,190 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.TreeMap;
+
+/**
+ * Compares the make-based configuration as reported by dumpconfig.mk
+ * with what was computed from the new tool.
+ */
+public class OutputChecker {
+    // Differences that we know about, either know issues to be fixed or intentional.
+    private static final RegexSet IGNORED_VARIABLES = new RegexSet(
+            // TODO: Rewrite the enforce packages exist logic into this tool.
+            "PRODUCT_ENFORCE_PACKAGES_EXIST",
+            "PRODUCT_ENFORCE_PACKAGES_EXIST_ALLOW_LIST",
+            "PRODUCTS\\..*\\.PRODUCT_ENFORCE_PACKAGES_EXIST",
+            "PRODUCTS\\..*\\.PRODUCT_ENFORCE_PACKAGES_EXIST_ALLOW_LIST",
+
+            // This is generated by this tool, but comes later in the make build system.
+            "INTERNAL_PRODUCT",
+
+            // This can be set temporarily by product_config.mk
+            ".KATI_ALLOW_RULES"
+            );
+
+    private final FlatConfig mConfig;
+    private final TreeMap<String, Variable> mVariables;
+
+    /**
+     * Represents the before and after state of a variable.
+     */
+    public static class Variable {
+        public final String name;
+        public final VarType type;
+        public final Str original;
+        public final Value updated;
+
+        public Variable(String name, VarType type, Str original) {
+            this(name, type, original, null);
+        }
+
+        public Variable(String name, VarType type, Str original, Value updated) {
+            this.name = name;
+            this.type = type;
+            this.original = original;
+            this.updated = updated;
+        }
+
+        /**
+         * Return copy of this Variable with the updated field also set.
+         */
+        public Variable addUpdated(Value updated) {
+            return new Variable(name, type, original, updated);
+        }
+
+        /**
+         * Return whether normalizedOriginal and normalizedUpdate are equal.
+         */
+        public boolean isSame() {
+            final Str normalizedOriginal = Value.normalize(original);
+            final Str normalizedUpdated = Value.normalize(updated);
+            if (normalizedOriginal == null && normalizedUpdated == null) {
+                return true;
+            } else if (normalizedOriginal != null) {
+                return normalizedOriginal.equals(normalizedUpdated);
+            } else {
+                return false;
+            }
+        }
+    }
+
+    /**
+     * Construct OutputChecker with the config it will check.
+     */
+    public OutputChecker(FlatConfig config) {
+        mConfig = config;
+        mVariables = getVariables(config);
+    }
+
+    /**
+     * Add a WARNING_DIFFERENT_FROM_KATI for each of the variables which have changed.
+     */
+    public void reportErrors(Errors errors) {
+        for (Variable var: getDifferences()) {
+            if (IGNORED_VARIABLES.matches(var.name)) {
+                continue;
+            }
+            errors.WARNING_DIFFERENT_FROM_KATI.add("product_config processing differs from"
+                    + " kati processing for " + var.type + " variable " + var.name + ".\n"
+                    + "original: "
+                    + Value.oneLinePerWord(var.original, "<null>") + "\n"
+                    + "updated: "
+                    + Value.oneLinePerWord(var.updated, "<null>"));
+        }
+    }
+
+    /**
+     * Get the Variables that are different between the normalized form of the original
+     * and updated.  If one is null and the other is not, even if one is an empty string,
+     * the values are considered different.
+     */
+    public List<Variable> getDifferences() {
+        final ArrayList<Variable> result = new ArrayList();
+        for (Variable var: mVariables.values()) {
+            if (!var.isSame()) {
+                result.add(var);
+            }
+        }
+        return result;
+    }
+
+    /**
+     * Get all of the variables for this config.
+     *
+     * VisibleForTesting
+     */
+    static TreeMap<String, Variable> getVariables(FlatConfig config) {
+        final TreeMap<String, Variable> result = new TreeMap();
+
+        // Add the original values to mAll
+        for (Map.Entry<String, Str> entry: getModifiedVars(config.getInitialVariables(),
+                    config.getFinalVariables()).entrySet()) {
+            final String name = entry.getKey();
+            result.put(name, new Variable(name, config.getVarType(name), entry.getValue()));
+        }
+
+        // Add the updated values to mAll
+        for (Map.Entry<String, Value> entry: config.getValues().entrySet()) {
+            final String name = entry.getKey();
+            final Value value = entry.getValue();
+            Variable var = result.get(name);
+            if (var == null) {
+                result.put(name, new Variable(name, config.getVarType(name), null, value));
+            } else {
+                result.put(name, var.addUpdated(value));
+            }
+        }
+
+        return result;
+    }
+
+    /**
+     * Get the entries that are different in the two maps.
+     */
+    public static Map<String, Str> getModifiedVars(Map<String, Str> before,
+            Map<String, Str> after) {
+        final HashMap<String, Str> result = new HashMap();
+
+        // Entries that were added or changed.
+        for (Map.Entry<String, Str> afterEntry: after.entrySet()) {
+            final String varName = afterEntry.getKey();
+            final Str afterValue = afterEntry.getValue();
+            final Str beforeValue = before.get(varName);
+            if (beforeValue == null || !beforeValue.equals(afterValue)) {
+                result.put(varName, afterValue);
+            }
+        }
+
+        // removed Entries that were removed, we just treat them as empty string
+        for (Map.Entry<String, Str> beforeEntry: before.entrySet()) {
+            final String varName = beforeEntry.getKey();
+            if (!after.containsKey(varName)) {
+                result.put(varName, new Str(""));
+            }
+        }
+
+        return result;
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/Position.java b/tools/product_config/src/com/android/build/config/Position.java
index 7953942..266021d 100644
--- a/tools/product_config/src/com/android/build/config/Position.java
+++ b/tools/product_config/src/com/android/build/config/Position.java
@@ -16,6 +16,9 @@
 
 package com.android.build.config;
 
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
 /**
  * Position in a source file.
  */
@@ -25,6 +28,9 @@
      */
     public static final int NO_LINE = -1;
 
+    private static final Pattern REGEX = Pattern.compile("([^:]*)(?::(\\d)*)?:?\\s*");
+    public static final String UNKNOWN = "<unknown>";
+
     private final String mFile;
     private final int mLine;
 
@@ -63,12 +69,39 @@
         return mLine;
     }
 
+    /**
+     * Return a Position object from a string containing <filename>:<line>, or the default
+     * Position(null, NO_LINE) if the string can't be parsed.
+     */
+    public static Position parse(String str) {
+        final Matcher m = REGEX.matcher(str);
+        if (!m.matches()) {
+            return new Position();
+        }
+        String filename = m.group(1);
+        if (filename.length() == 0 || UNKNOWN.equals(filename)) {
+            filename = null;
+        }
+        String lineString = m.group(2);
+        int line;
+        if (lineString == null || lineString.length() == 0) {
+            line = NO_LINE;
+        } else {
+            try {
+                line = Integer.parseInt(lineString);
+            } catch (NumberFormatException ex) {
+                line = NO_LINE;
+            }
+        }
+        return new Position(filename, line);
+    }
+
     @Override
     public String toString() {
       if (mFile == null && mLine == NO_LINE) {
         return "";
       } else if (mFile == null && mLine != NO_LINE) {
-        return "<unknown>:" + mLine + ": ";
+        return UNKNOWN + ":" + mLine + ": ";
       } else if (mFile != null && mLine == NO_LINE) {
         return mFile + ": ";
       } else { // if (mFile != null && mLine != NO_LINE)
diff --git a/tools/product_config/src/com/android/build/config/RegexSet.java b/tools/product_config/src/com/android/build/config/RegexSet.java
new file mode 100644
index 0000000..70fcd29
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/RegexSet.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.util.regex.Pattern;
+
+/**
+ * Returns whether a string matches one of a set of presupplied regexes.
+ */
+public class RegexSet {
+    private final Pattern[] mPatterns;
+
+    public RegexSet(String... patterns) {
+        mPatterns = new Pattern[patterns.length];
+        for (int i = 0; i < patterns.length; i++) {
+            mPatterns[i] = Pattern.compile(patterns[i]);
+        }
+    }
+
+    public boolean matches(String s) {
+        for (Pattern p: mPatterns) {
+            if (p.matcher(s).matches()) {
+                return true;
+            }
+        }
+        return false;
+    }
+}
+
diff --git a/tools/product_config/src/com/android/build/config/Str.java b/tools/product_config/src/com/android/build/config/Str.java
new file mode 100644
index 0000000..2516b76
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/Str.java
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A String and a Position, where it came from in source code.
+ */
+public class Str implements Comparable<Str> {
+    private String mValue;
+    private Position mPosition;
+
+    public Str(String s) {
+        mValue = s;
+        mPosition = new Position();
+    }
+
+    public Str(Position pos, String s) {
+        mValue = s;
+        mPosition = pos;
+    }
+
+    public int length() {
+        return mValue.length();
+    }
+
+    @Override
+    public String toString() {
+        return mValue;
+    }
+
+    public Position getPosition() {
+        return mPosition;
+    }
+
+    /**
+     * Str is equal if the string value is equal, regardless of whether the position
+     * is the same.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof Str)) {
+            return false;
+        }
+        final Str that = (Str)o;
+        return mValue.equals(that.mValue);
+    }
+
+    @Override
+    public int hashCode() {
+        return mValue.hashCode();
+    }
+
+    @Override
+    public int compareTo(Str that) {
+        return this.mValue.compareTo(that.mValue);
+    }
+
+    public static ArrayList<Str> toList(Position pos, List<String> list) {
+        final ArrayList<Str> result = new ArrayList(list.size());
+        for (String s: list) {
+            result.add(new Str(pos, s));
+        }
+        return result;
+    }
+}
diff --git a/tools/product_config/src/com/android/build/config/Value.java b/tools/product_config/src/com/android/build/config/Value.java
new file mode 100644
index 0000000..9bd6401
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/Value.java
@@ -0,0 +1,218 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Pattern;
+import java.util.regex.Matcher;
+
+/**
+ * Class to hold the two types of variables we support, strings and lists of strings.
+ */
+public class Value {
+    private static final Pattern SPACES = Pattern.compile("\\s+");
+
+    private final VarType mVarType;
+    private final Str mStr;
+    private final ArrayList<Str> mList;
+
+    /**
+     * Construct an appropriately typed empty value.
+     */
+    public Value(VarType varType) {
+        mVarType = varType;
+        if (varType == VarType.LIST) {
+            mStr = null;
+            mList = new ArrayList();
+            mList.add(new Str(""));
+        } else {
+            mStr = new Str("");
+            mList = null;
+        }
+    }
+
+    public Value(VarType varType, Str str) {
+        mVarType = varType;
+        mStr = str;
+        mList = null;
+    }
+
+    public Value(List<Str> list) {
+        mVarType = VarType.LIST;
+        mStr = null;
+        mList = new ArrayList(list);
+    }
+
+    public VarType getVarType() {
+        return mVarType;
+    }
+
+    public Str getStr() {
+        return mStr;
+    }
+
+    public List<Str> getList() {
+        return mList;
+    }
+
+    /**
+     * Normalize a string that is behaving as a list.
+     */
+    public static String normalize(String str) {
+        if (str == null) {
+            return null;
+        }
+        return SPACES.matcher(str.trim()).replaceAll(" ").trim();
+    }
+
+    /**
+     * Normalize a string that is behaving as a list.
+     */
+    public static Str normalize(Str str) {
+        if (str == null) {
+            return null;
+        }
+        return new Str(str.getPosition(), normalize(str.toString()));
+    }
+
+    /**
+     * Normalize a this Value into the same format as normalize(Str).
+     */
+    public static Str normalize(Value val) {
+        if (val == null) {
+            return null;
+        }
+        if (val.mStr != null) {
+            return normalize(val.mStr);
+        }
+
+        if (val.mList.size() == 0) {
+            return new Str("");
+        }
+
+        StringBuilder result = new StringBuilder();
+        final int size = val.mList.size();
+        boolean first = true;
+        for (int i = 0; i < size; i++) {
+            String s = val.mList.get(i).toString().trim();
+            if (s.length() > 0) {
+                if (!first) {
+                    result.append(" ");
+                } else {
+                    first = false;
+                }
+                result.append(s);
+            }
+        }
+
+        // Just use the first item's position.
+        return new Str(val.mList.get(0).getPosition(), result.toString());
+    }
+
+    /**
+     * Put each word in 'str' on its own line in make format. If 'val' is null,
+     * 'nullValue' is returned.
+     */
+    public static String oneLinePerWord(Value val, String nullValue) {
+        if (val == null) {
+            return nullValue;
+        }
+        final String s = normalize(val).toString();
+        final Matcher m = SPACES.matcher(s);
+        final StringBuilder result = new StringBuilder();
+        if (s.length() > 0 && (val.mVarType == VarType.LIST || m.find())) {
+            result.append("\\\n  ");
+        }
+        result.append(m.replaceAll(" \\\\\n  "));
+        return result.toString();
+    }
+
+    /**
+     * Put each word in 'str' on its own line in make format. If 'str' is null,
+     * nullValue is returned.
+     */
+    public static String oneLinePerWord(Str str, String nullValue) {
+        if (str == null) {
+            return nullValue;
+        }
+        final Matcher m = SPACES.matcher(normalize(str.toString()));
+        final StringBuilder result = new StringBuilder();
+        if (m.find()) {
+            result.append("\\\n  ");
+        }
+        result.append(m.replaceAll(" \\\\\n  "));
+        return result.toString();
+    }
+
+    /**
+     * Return a string representing this value with detailed debugging information.
+     */
+    public static String debugString(Value val) {
+        if (val == null) {
+            return "null";
+        }
+
+        final StringBuilder str = new StringBuilder("Value(");
+        if (val.mStr != null) {
+            str.append("mStr=");
+            str.append("\"");
+            str.append(val.mStr.toString());
+            str.append("\"");
+            if (false) {
+                str.append(" (");
+                str.append(val.mStr.getPosition().toString());
+                str.append(")");
+            }
+        }
+        if (val.mList != null) {
+            str.append("mList=");
+            str.append("[");
+            for (Str s: val.mList) {
+                str.append(" \"");
+                str.append(s.toString());
+                if (false) {
+                    str.append("\" (");
+                    str.append(s.getPosition().toString());
+                    str.append(")");
+                } else {
+                    str.append("\"");
+                }
+            }
+            str.append(" ]");
+        }
+        str.append(")");
+        return str.toString();
+    }
+
+    /**
+     * Get the Positions of all of the parts of this Value.
+     */
+    public List<Position> getPositions() {
+        List<Position> result = new ArrayList();
+        if (mStr != null) {
+            result.add(mStr.getPosition());
+        }
+        if (mList != null) {
+            for (Str str: mList) {
+                result.add(str.getPosition());
+            }
+        }
+        return result;
+    }
+}
+
diff --git a/tools/product_config/src/com/android/build/config/VarType.java b/tools/product_config/src/com/android/build/config/VarType.java
new file mode 100644
index 0000000..43e9366
--- /dev/null
+++ b/tools/product_config/src/com/android/build/config/VarType.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+/**
+ * Whether a product config variable is a list or single-value variable.
+ */
+public enum VarType {
+    /**
+     * A product config variable that is a list of space separated strings.
+     * These are defined by _product_single_value_vars in product.mk.
+     */
+    LIST,
+
+    /**
+     * A product config varaible that is a single string.
+     * These are defined by _product_list_vars in product.mk.
+     */
+    SINGLE,
+
+    /**
+     * A variable that is given the special product config handling but is
+     * nonetheless defined by product config makefiles.
+     */
+    UNKNOWN
+}
+
diff --git a/tools/product_config/test.sh b/tools/product_config/test.sh
new file mode 100755
index 0000000..ee9ed5c
--- /dev/null
+++ b/tools/product_config/test.sh
@@ -0,0 +1,120 @@
+#!/bin/bash
+
+#
+# This script runs the full set of tests for product config:
+# 1. Build the product-config tool.
+# 2. Run the unit tests.
+# 3. Run the product config for every product available in the current
+#    source tree, for each of user, userdebug and eng.
+#       - To restrict which products or variants are run, set the
+#         PRODUCTS or VARIANTS environment variables.
+#       - Products for which the make based product config fails are
+#         skipped.
+#
+
+# The PRODUCTS variable is used by the build, and setting it in the environment
+# interferes with that, so unset it.  (That should probably be fixed)
+products=$PRODUCTS
+variants=$VARIANTS
+unset PRODUCTS
+unset VARIANTS
+
+# Don't use lunch from the user's shell
+unset TARGET_PRODUCT
+unset TARGET_BUILD_VARIANT
+
+function die() {
+    format=$1
+    shift
+    printf "$format\nStopping...\n" $@ >&2
+    exit 1;
+}
+
+[[ -f build/make/envsetup.sh ]] || die "Run this script from the root of the tree."
+: ${products:=$(build/soong/soong_ui.bash --dumpvar-mode all_named_products | sed -e "s/ /\n/g" | sort -u )}
+: ${variants:="user userdebug eng"}
+: ${CKATI_BIN:=prebuilts/build-tools/$(build/soong/soong_ui.bash --dumpvar-mode HOST_PREBUILT_TAG)/bin/ckati}
+
+function if_signal_exit() {
+    [[ $1 -lt 128 ]] || exit $1
+}
+
+build/soong/soong_ui.bash --build-mode --all-modules --dir="$(pwd)" product-config-test product-config \
+    || die "Build failed."
+
+echo
+echo Running unit tests
+java -jar out/host/linux-x86/testcases/product-config-test/product-config-test.jar
+unit_tests=$?
+if_signal_exit $unit_tests
+
+failed_baseline_checks=
+for product in $products ; do
+    for variant in $variants ; do
+        echo
+        echo "Checking: lunch $product-$variant"
+
+        TARGET_PRODUCT=$product \
+            TARGET_BUILD_VARIANT=$variant \
+            build/soong/soong_ui.bash --dumpvar-mode TARGET_PRODUCT &> /dev/null
+        exit_status=$?
+        if_signal_exit $exit_status
+        if [ $exit_status -ne 0 ] ; then
+            echo "*** Combo fails with make, skipping product-config test run for $product-$variant"
+        else
+            rm -rf out/config/$product-$variant
+            TARGET_PRODUCT=$product TARGET_BUILD_VARIANT=$variant product-config \
+                            --ckati_bin $CKATI_BIN \
+                            --error 1000
+            exit_status=$?
+            if_signal_exit $exit_status
+            if [ $exit_status -ne 0 ] ; then
+                failed_baseline_checks="$failed_baseline_checks $product-$variant"
+            fi
+            if [ "$CHECK_FOR_RULES" != "" ] ; then
+                # This is a little bit of sleight of hand for good output formatting at the
+                # expense of speed. We've already run the command once without
+                # ALLOW_RULES_IN_PRODUCT_CONFIG, so we know it passes there. We run it again
+                # with ALLOW_RULES_IN_PRODUCT_CONFIG=error to see if it fails, but that will
+                # cause it to only print the first error. But we want to see all of them,
+                # so if it fails we run it a third time with ALLOW_RULES_IN_PRODUCT_CONFIG=warning,
+                # so we can see all the warnings.
+                TARGET_PRODUCT=$product \
+                    TARGET_BUILD_VARIANT=$variant \
+                    ALLOW_RULES_IN_PRODUCT_CONFIG=error \
+                    build/soong/soong_ui.bash --dumpvar-mode TARGET_PRODUCT &> /dev/null
+                exit_status=$?
+                if_signal_exit $exit_status
+                if [ $exit_status -ne 0 ] ; then
+                    TARGET_PRODUCT=$product \
+                        TARGET_BUILD_VARIANT=$variant \
+                        ALLOW_RULES_IN_PRODUCT_CONFIG=warning \
+                        build/soong/soong_ui.bash --dumpvar-mode TARGET_PRODUCT > /dev/null
+                    failed_rule_checks="$failed_rule_checks $product-$variant"
+                fi
+            fi
+        fi
+    done
+done
+
+echo
+echo
+echo "------------------------------"
+echo SUMMARY
+echo "------------------------------"
+
+echo -n "Unit tests        "
+if [ $unit_tests -eq 0 ] ; then echo PASSED ; else echo FAILED ; fi
+
+echo -n "Baseline checks   "
+if [ "$failed_baseline_checks" = "" ] ; then echo PASSED ; else echo FAILED ; fi
+for combo in $failed_baseline_checks ; do
+    echo "                   ... $combo"
+done
+
+echo -n "Rules checks      "
+if [ "$failed_rule_checks" = "" ] ; then echo PASSED ; else echo FAILED ; fi
+for combo in $failed_rule_checks ; do
+    echo "                   ... $combo"
+done
+
diff --git a/tools/product_config/test/com/android/build/config/CsvParserTest.java b/tools/product_config/test/com/android/build/config/CsvParserTest.java
new file mode 100644
index 0000000..6f38d68
--- /dev/null
+++ b/tools/product_config/test/com/android/build/config/CsvParserTest.java
@@ -0,0 +1,148 @@
+
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+package com.android.build.config;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.io.StringReader;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * Test for CSV parser class.
+ */
+public class CsvParserTest {
+    public String listsToStrings(String[] expected, List<String> actual) {
+        return "expected=" + Arrays.toString(expected)
+                + " actual=" + Arrays.toString(actual.toArray());
+    }
+
+    public void assertLineEquals(CsvParser.Line actual, int lineno, String... fields) {
+        if (actual.getLine() != lineno) {
+            throw new RuntimeException("lineno mismatch: expected=" + lineno
+                    + " actual=" + actual.getLine());
+        }
+        if (fields.length != actual.getFields().size()) {
+            throw new RuntimeException("getFields().size() mismatch: expected=" + fields.length
+                    + " actual=" + actual.getFields().size()
+                    + " values: " + listsToStrings(fields, actual.getFields()));
+        }
+        for (int i = 0; i < fields.length; i++) {
+            if (!fields[i].equals(actual.getFields().get(i))) {
+                throw new RuntimeException("getFields().get(" + i + ") mismatch: expected="
+                        + fields[i] + " actual=" + actual.getFields().get(i)
+                        + " values: " + listsToStrings(fields, actual.getFields()));
+
+            }
+        }
+    }
+
+    @Test
+    public void testEmptyString() throws Exception {
+        List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                    ""));
+
+        Assert.assertEquals(0, lines.size());
+    }
+
+    @Test
+    public void testLexerOneCharacter() throws Exception {
+        List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                    "a"));
+
+        Assert.assertEquals(1, lines.size());
+        assertLineEquals(lines.get(0), 1, "a");
+    }
+
+    @Test
+    public void testLexerTwoFieldsNoNewline() throws Exception {
+        List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                    "a,b"));
+
+        Assert.assertEquals(1, lines.size());
+        assertLineEquals(lines.get(0), 1, "a", "b");
+    }
+
+    @Test
+    public void testLexerTwoFieldsNewline() throws Exception {
+        List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                    "a,b\n"));
+
+        Assert.assertEquals(1, lines.size());
+        assertLineEquals(lines.get(0), 1, "a", "b");
+    }
+
+    @Test
+    public void testEndsWithTwoNewlines() throws Exception {
+        List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                    "a,b\n\n"));
+
+        Assert.assertEquals(1, lines.size());
+        assertLineEquals(lines.get(0), 1, "a", "b");
+    }
+
+    @Test
+    public void testOnlyNewlines() throws Exception {
+        List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                    "\n\n\n\n"));
+
+        Assert.assertEquals(0, lines.size());
+    }
+
+
+    @Test
+    public void testLexerComplex() throws Exception {
+        List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                    ",\"ab\"\"\nc\",,de\n"
+                    + "fg,\n"
+                    + "\n"
+                    + ",\n"
+                    + "hijk"));
+
+        Assert.assertEquals(4, lines.size());
+        assertLineEquals(lines.get(0), 2, "", "ab\"\nc", "", "de");
+        assertLineEquals(lines.get(1), 3, "fg", "");
+        assertLineEquals(lines.get(2), 5, "", "");
+        assertLineEquals(lines.get(3), 6, "hijk");
+    }
+
+    @Test
+    public void testEndInsideQuoted() throws Exception {
+        try {
+            List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                        "\"asd"));
+            throw new RuntimeException("Didn't throw ParseException");
+        } catch (CsvParser.ParseException ex) {
+            System.out.println("Caught: " + ex);
+        }
+    }
+
+    @Test
+    public void testCharacterAfterQuotedField() throws Exception {
+        try {
+            List<CsvParser.Line> lines = CsvParser.parse(new StringReader(
+                        "\"\"a"));
+            throw new RuntimeException("Didn't throw ParseException");
+        } catch (CsvParser.ParseException ex) {
+            System.out.println("Caught: " + ex);
+        }
+    }
+}
+
diff --git a/tools/product_config/test/com/android/build/config/OptionsTest.java b/tools/product_config/test/com/android/build/config/OptionsTest.java
index 2c36322..459efa5 100644
--- a/tools/product_config/test/com/android/build/config/OptionsTest.java
+++ b/tools/product_config/test/com/android/build/config/OptionsTest.java
@@ -19,12 +19,24 @@
 import org.junit.Assert;
 import org.junit.Test;
 
+import java.util.HashMap;
+
 public class OptionsTest {
+
+    private Options parse(Errors errors, String[] args) {
+        final HashMap<String, String> env = new HashMap();
+        env.put("TARGET_PRODUCT", "test_product");
+        env.put("TARGET_BUILD_VARIANT", "user");
+        final Options.Parser parser = new Options.Parser(errors, args, env);
+        parser.setSkipRequiredArgValidation();
+        return parser.parse();
+    }
+
     @Test
     public void testErrorMissingLast() {
         final Errors errors = new Errors();
 
-        final Options options = Options.parse(errors, new String[] {
+        final Options options = parse(errors, new String[] {
                     "--error"
                 });
 
@@ -37,7 +49,7 @@
     public void testErrorMissingNotLast() {
         final Errors errors = new Errors();
 
-        final Options options = Options.parse(errors, new String[] {
+        final Options options = parse(errors, new String[] {
                     "--error", "--warning", "2"
                 });
 
@@ -50,7 +62,7 @@
     public void testErrorNotNumeric() {
         final Errors errors = new Errors();
 
-        final Options options = Options.parse(errors, new String[] {
+        final Options options = parse(errors, new String[] {
                     "--error", "notgood"
                 });
 
@@ -63,7 +75,7 @@
     public void testErrorInvalidError() {
         final Errors errors = new Errors();
 
-        final Options options = Options.parse(errors, new String[] {
+        final Options options = parse(errors, new String[] {
                     "--error", "50000"
                 });
 
@@ -76,7 +88,7 @@
     public void testErrorOne() {
         final Errors errors = new Errors();
 
-        final Options options = Options.parse(errors, new String[] {
+        final Options options = parse(errors, new String[] {
                     "--error", "2"
                 });
 
@@ -89,7 +101,7 @@
     public void testWarningOne() {
         final Errors errors = new Errors();
 
-        final Options options = Options.parse(errors, new String[] {
+        final Options options = parse(errors, new String[] {
                     "--warning", "2"
                 });
 
@@ -102,7 +114,7 @@
     public void testHideOne() {
         final Errors errors = new Errors();
 
-        final Options options = Options.parse(errors, new String[] {
+        final Options options = parse(errors, new String[] {
                     "--hide", "2"
                 });
 
@@ -110,5 +122,16 @@
         Assert.assertEquals(Options.Action.DEFAULT, options.getAction());
         Assert.assertFalse(errors.hadWarningOrError());
     }
+
+    @Test
+    public void testEnv() {
+        final Errors errors = new Errors();
+
+        final Options options = parse(errors, new String[0]);
+
+        Assert.assertEquals("test_product", options.getProduct());
+        Assert.assertEquals("user", options.getVariant());
+        Assert.assertFalse(errors.hadWarningOrError());
+    }
 }
 
diff --git a/tools/product_config/test/com/android/build/config/PositionTest.java b/tools/product_config/test/com/android/build/config/PositionTest.java
new file mode 100644
index 0000000..82b5dd4
--- /dev/null
+++ b/tools/product_config/test/com/android/build/config/PositionTest.java
@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.build.config;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.HashMap;
+
+public class PositionTest {
+
+    @Test
+    public void testParseEmpty() {
+        final Position pos = Position.parse("");
+
+        Assert.assertEquals(null, pos.getFile());
+        Assert.assertEquals(Position.NO_LINE, pos.getLine());
+    }
+
+    @Test
+    public void testParseOnlyFile() {
+        final Position pos = Position.parse("asdf");
+
+        Assert.assertEquals("asdf", pos.getFile());
+        Assert.assertEquals(Position.NO_LINE, pos.getLine());
+    }
+
+    @Test
+    public void testParseBoth() {
+        final Position pos = Position.parse("asdf:1");
+
+        Assert.assertEquals("asdf", pos.getFile());
+        Assert.assertEquals(1, pos.getLine());
+    }
+
+    @Test
+    public void testParseEndsWithColon() {
+        final Position pos = Position.parse("asdf:");
+
+        Assert.assertEquals("asdf", pos.getFile());
+        Assert.assertEquals(Position.NO_LINE, pos.getLine());
+    }
+
+    @Test
+    public void testParseEndsWithSpace() {
+        final Position pos = Position.parse("asdf: ");
+
+        Assert.assertEquals("asdf", pos.getFile());
+        Assert.assertEquals(Position.NO_LINE, pos.getLine());
+    }
+
+
+}
+
diff --git a/tools/product_config/test/com/android/build/config/TestRunner.java b/tools/product_config/test/com/android/build/config/TestRunner.java
index 9a5ee69..546518f 100644
--- a/tools/product_config/test/com/android/build/config/TestRunner.java
+++ b/tools/product_config/test/com/android/build/config/TestRunner.java
@@ -39,8 +39,10 @@
                         System.out.println(failure.getTrace());
                     }
                 });
-        Result result = junit.run(ErrorReporterTest.class,
-                                  OptionsTest.class);
+        Result result = junit.run(CsvParserTest.class,
+                                  ErrorReporterTest.class,
+                                  OptionsTest.class,
+                                  PositionTest.class);
         if (!result.wasSuccessful()) {
             System.out.println("\n*** FAILED ***");
         }
diff --git a/tools/releasetools/Android.bp b/tools/releasetools/Android.bp
index 81528ae..6d88249 100644
--- a/tools/releasetools/Android.bp
+++ b/tools/releasetools/Android.bp
@@ -451,6 +451,7 @@
     required: [
         "checkvintf",
         "host_init_verifier",
+        "secilc",
     ],
     target: {
         darwin: {
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index da189f3..3ede4c5 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -1691,6 +1691,11 @@
   cmd.extend(["--vendor_ramdisk", ramdisk_img.name])
   cmd.extend(["--vendor_boot", img.name])
 
+  fn = os.path.join(sourcedir, "vendor_bootconfig")
+  if os.access(fn, os.F_OK):
+    cmd.append("--vendor_bootconfig")
+    cmd.append(fn)
+
   ramdisk_fragment_imgs = []
   fn = os.path.join(sourcedir, "vendor_ramdisk_fragments")
   if os.access(fn, os.F_OK):
@@ -1934,12 +1939,13 @@
     # filename listed in system.map may contain an additional leading slash
     # (i.e. "//system/framework/am.jar"). Using lstrip to get consistent
     # results.
-    arcname = entry.replace(which, which.upper(), 1).lstrip('/')
-
-    # Special handling another case, where files not under /system
+    # And handle another special case, where files not under /system
     # (e.g. "/sbin/charger") are packed under ROOT/ in a target_files.zip.
-    if which == 'system' and not arcname.startswith('SYSTEM'):
+    arcname = entry.lstrip('/')
+    if which == 'system' and not arcname.startswith('system'):
       arcname = 'ROOT/' + arcname
+    else:
+      arcname = arcname.replace(which, which.upper(), 1)
 
     assert arcname in input_zip.namelist(), \
         "Failed to find the ZIP entry for {}".format(entry)
diff --git a/tools/releasetools/merge_target_files.py b/tools/releasetools/merge_target_files.py
index 3d9c717..16cab4f 100755
--- a/tools/releasetools/merge_target_files.py
+++ b/tools/releasetools/merge_target_files.py
@@ -93,6 +93,7 @@
 import subprocess
 import sys
 import zipfile
+from xml.etree import ElementTree
 
 import add_img_to_target_files
 import build_super_image
@@ -658,6 +659,80 @@
       os.path.join(output_target_files_dir, 'META', 'vendor_file_contexts.bin'))
 
 
+def compile_split_sepolicy(product_out, partition_map, output_policy):
+  """Uses secilc to compile a split sepolicy file.
+
+  Depends on various */etc/selinux/* and */etc/vintf/* files within partitions.
+
+  Args:
+    product_out: PRODUCT_OUT directory, containing partition directories.
+    partition_map: A map of partition name -> relative path within product_out.
+    output_policy: The name of the output policy created by secilc.
+
+  Returns:
+    A command list that can be executed to create the compiled sepolicy.
+  """
+
+  def get_file(partition, path):
+    if partition not in partition_map:
+      logger.warning('Cannot load SEPolicy files for missing partition %s',
+                     partition)
+      return None
+    return os.path.join(product_out, partition_map[partition], path)
+
+  # Load the kernel sepolicy version from the FCM. This is normally provided
+  # directly to selinux.cpp as a build flag, but is also available in this file.
+  fcm_file = get_file('system', 'etc/vintf/compatibility_matrix.device.xml')
+  if not fcm_file or not os.path.exists(fcm_file):
+    raise ExternalError('Missing required file for loading sepolicy: %s', fcm)
+  kernel_sepolicy_version = ElementTree.parse(fcm_file).getroot().find(
+      'sepolicy/kernel-sepolicy-version').text
+
+  # Load the vendor's plat sepolicy version. This is the version used for
+  # locating sepolicy mapping files.
+  vendor_plat_version_file = get_file('vendor',
+                                      'etc/selinux/plat_sepolicy_vers.txt')
+  if not vendor_plat_version_file or not os.path.exists(
+      vendor_plat_version_file):
+    raise ExternalError('Missing required sepolicy file %s',
+                        vendor_plat_version_file)
+  with open(vendor_plat_version_file) as f:
+    vendor_plat_version = f.read().strip()
+
+  # Use the same flags and arguments as selinux.cpp OpenSplitPolicy().
+  cmd = ['secilc', '-m', '-M', 'true', '-G', '-N']
+  cmd.extend(['-c', kernel_sepolicy_version])
+  cmd.extend(['-o', output_policy])
+  cmd.extend(['-f', '/dev/null'])
+
+  required_policy_files = (
+      ('system', 'etc/selinux/plat_sepolicy.cil'),
+      ('system', 'etc/selinux/mapping/%s.cil' % vendor_plat_version),
+      ('vendor', 'etc/selinux/vendor_sepolicy.cil'),
+      ('vendor', 'etc/selinux/plat_pub_versioned.cil'),
+  )
+  for policy in (map(lambda partition_and_path: get_file(*partition_and_path),
+                     required_policy_files)):
+    if not policy or not os.path.exists(policy):
+      raise ExternalError('Missing required sepolicy file %s', policy)
+    cmd.append(policy)
+
+  optional_policy_files = (
+      ('system', 'etc/selinux/mapping/%s.compat.cil' % vendor_plat_version),
+      ('system_ext', 'etc/selinux/system_ext_sepolicy.cil'),
+      ('system_ext', 'etc/selinux/mapping/%s.cil' % vendor_plat_version),
+      ('product', 'etc/selinux/product_sepolicy.cil'),
+      ('product', 'etc/selinux/mapping/%s.cil' % vendor_plat_version),
+      ('odm', 'etc/selinux/odm_sepolicy.cil'),
+  )
+  for policy in (map(lambda partition_and_path: get_file(*partition_and_path),
+                     optional_policy_files)):
+    if policy and os.path.exists(policy):
+      cmd.append(policy)
+
+  return cmd
+
+
 def process_special_cases(framework_target_files_temp_dir,
                           vendor_target_files_temp_dir,
                           output_target_files_temp_dir,
@@ -977,17 +1052,28 @@
       raise ValueError('sharedUserId APK error. See %s' %
                        shareduid_violation_modules)
 
-  # Run host_init_verifier on the combined init rc files.
+  # host_init_verifier and secilc check only the following partitions:
   filtered_partitions = {
       partition: path
       for partition, path in partition_map.items()
-      # host_init_verifier checks only the following partitions:
       if partition in ['system', 'system_ext', 'product', 'vendor', 'odm']
   }
+
+  # Run host_init_verifier on the combined init rc files.
   common.RunHostInitVerifier(
       product_out=output_target_files_temp_dir,
       partition_map=filtered_partitions)
 
+  # Check that the split sepolicy from the multiple builds can compile.
+  split_sepolicy_cmd = compile_split_sepolicy(
+      product_out=output_target_files_temp_dir,
+      partition_map=filtered_partitions,
+      output_policy=os.path.join(output_target_files_temp_dir,
+                                 'META/combined.policy'))
+  logger.info('Compiling split sepolicy: %s', ' '.join(split_sepolicy_cmd))
+  common.RunAndCheckOutput(split_sepolicy_cmd)
+  # TODO(b/178864050): Run tests on the combined.policy file.
+
   generate_images(output_target_files_temp_dir, rebuild_recovery)
 
   generate_super_empty_image(output_target_files_temp_dir, output_super_empty)
diff --git a/tools/releasetools/ota_from_target_files.py b/tools/releasetools/ota_from_target_files.py
index 2cbaf37..3dcabd5 100755
--- a/tools/releasetools/ota_from_target_files.py
+++ b/tools/releasetools/ota_from_target_files.py
@@ -230,7 +230,7 @@
 import common
 import ota_utils
 from ota_utils import (UNZIP_PATTERN, FinalizeMetadata, GetPackageMetadata,
-                       PropertyFiles)
+                       PropertyFiles, SECURITY_PATCH_LEVEL_PROP_NAME)
 import target_files_diff
 from check_target_files_vintf import CheckVintfIfTrebleEnabled
 from non_ab_ota import GenerateNonAbOtaPackage
@@ -292,7 +292,7 @@
     'system_ext', 'vbmeta', 'vbmeta_system', 'vbmeta_vendor', 'vendor',
     'vendor_boot']
 
-SECURITY_PATCH_LEVEL_PROP_NAME = "ro.build.version.security_patch"
+
 
 
 class PayloadSigner(object):
@@ -1418,14 +1418,20 @@
     target_build_prop = OPTIONS.target_info_dict["build.prop"]
     source_spl = source_build_prop.GetProp(SECURITY_PATCH_LEVEL_PROP_NAME)
     target_spl = target_build_prop.GetProp(SECURITY_PATCH_LEVEL_PROP_NAME)
-    if target_spl < source_spl and not OPTIONS.spl_downgrade:
+    is_spl_downgrade = target_spl < source_spl
+    if is_spl_downgrade and not OPTIONS.spl_downgrade:
       raise common.ExternalError(
         "Target security patch level {} is older than source SPL {} applying "
-        "such OTA will likely cause device fail to boot. Pass --spl-downgrade "
+        "such OTA will likely cause device fail to boot. Pass --spl_downgrade "
         "to override this check. This script expects security patch level to "
         "be in format yyyy-mm-dd (e.x. 2021-02-05). It's possible to use "
         "separators other than -, so as long as it's used consistenly across "
         "all SPL dates".format(target_spl, source_spl))
+    elif not is_spl_downgrade and OPTIONS.spl_downgrade:
+      raise ValueError("--spl_downgrade specified but no actual SPL downgrade"
+                       " detected. Please only pass in this flag if you want a"
+                       " SPL downgrade. Target SPL: {} Source SPL: {}"
+                       .format(target_spl, source_spl))
   if generate_ab:
     GenerateAbOtaPackage(
         target_file=args[0],
diff --git a/tools/releasetools/ota_metadata.proto b/tools/releasetools/ota_metadata.proto
index 5da8b84..7aaca6f 100644
--- a/tools/releasetools/ota_metadata.proto
+++ b/tools/releasetools/ota_metadata.proto
@@ -105,4 +105,7 @@
   bool retrofit_dynamic_partitions = 7;
   // The required size of the cache partition, only valid for non-A/B update.
   int64 required_cache = 8;
+
+  // True iff security patch level downgrade is permitted on this OTA.
+  bool spl_downgrade = 9;
 }
diff --git a/tools/releasetools/ota_metadata_pb2.py b/tools/releasetools/ota_metadata_pb2.py
index 27cc930..2552464 100644
--- a/tools/releasetools/ota_metadata_pb2.py
+++ b/tools/releasetools/ota_metadata_pb2.py
@@ -1,7 +1,9 @@
 # -*- coding: utf-8 -*-
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
 # source: ota_metadata.proto
-"""Generated protocol buffer code."""
+
+import sys
+_b=sys.version_info[0]<3 and (lambda x:x) or (lambda x:x.encode('latin1'))
 from google.protobuf import descriptor as _descriptor
 from google.protobuf import message as _message
 from google.protobuf import reflection as _reflection
@@ -17,9 +19,8 @@
   name='ota_metadata.proto',
   package='build.tools.releasetools',
   syntax='proto3',
-  serialized_options=b'H\003',
-  create_key=_descriptor._internal_create_key,
-  serialized_pb=b'\n\x12ota_metadata.proto\x12\x18\x62uild.tools.releasetools\"X\n\x0ePartitionState\x12\x16\n\x0epartition_name\x18\x01 \x01(\t\x12\x0e\n\x06\x64\x65vice\x18\x02 \x03(\t\x12\r\n\x05\x62uild\x18\x03 \x03(\t\x12\x0f\n\x07version\x18\x04 \x01(\t\"\xce\x01\n\x0b\x44\x65viceState\x12\x0e\n\x06\x64\x65vice\x18\x01 \x03(\t\x12\r\n\x05\x62uild\x18\x02 \x03(\t\x12\x19\n\x11\x62uild_incremental\x18\x03 \x01(\t\x12\x11\n\ttimestamp\x18\x04 \x01(\x03\x12\x11\n\tsdk_level\x18\x05 \x01(\t\x12\x1c\n\x14security_patch_level\x18\x06 \x01(\t\x12\x41\n\x0fpartition_state\x18\x07 \x03(\x0b\x32(.build.tools.releasetools.PartitionState\"c\n\x08\x41pexInfo\x12\x14\n\x0cpackage_name\x18\x01 \x01(\t\x12\x0f\n\x07version\x18\x02 \x01(\x03\x12\x15\n\ris_compressed\x18\x03 \x01(\x08\x12\x19\n\x11\x64\x65\x63ompressed_size\x18\x04 \x01(\x03\"E\n\x0c\x41pexMetadata\x12\x35\n\tapex_info\x18\x01 \x03(\x0b\x32\".build.tools.releasetools.ApexInfo\"\x98\x04\n\x0bOtaMetadata\x12;\n\x04type\x18\x01 \x01(\x0e\x32-.build.tools.releasetools.OtaMetadata.OtaType\x12\x0c\n\x04wipe\x18\x02 \x01(\x08\x12\x11\n\tdowngrade\x18\x03 \x01(\x08\x12P\n\x0eproperty_files\x18\x04 \x03(\x0b\x32\x38.build.tools.releasetools.OtaMetadata.PropertyFilesEntry\x12;\n\x0cprecondition\x18\x05 \x01(\x0b\x32%.build.tools.releasetools.DeviceState\x12<\n\rpostcondition\x18\x06 \x01(\x0b\x32%.build.tools.releasetools.DeviceState\x12#\n\x1bretrofit_dynamic_partitions\x18\x07 \x01(\x08\x12\x16\n\x0erequired_cache\x18\x08 \x01(\x03\x12\x35\n\tapex_info\x18\t \x03(\x0b\x32\".build.tools.releasetools.ApexInfo\x1a\x34\n\x12PropertyFilesEntry\x12\x0b\n\x03key\x18\x01 \x01(\t\x12\r\n\x05value\x18\x02 \x01(\t:\x02\x38\x01\"4\n\x07OtaType\x12\x0b\n\x07UNKNOWN\x10\x00\x12\x06\n\x02\x41\x42\x10\x01\x12\t\n\x05\x42LOCK\x10\x02\x12\t\n\x05\x42RICK\x10\x03\x42\x02H\x03\x62\x06proto3'
+  serialized_options=_b('H\003'),
+  serialized_pb=_b('\n\x12ota_metadata.proto\x12\x18\x62uild.tools.releasetools\"X\n\x0ePartitionState\x12\x16\n\x0epartition_name\x18\x01 \x01(\t\x12\x0e\n\x06\x64\x65vice\x18\x02 \x03(\t\x12\r\n\x05\x62uild\x18\x03 \x03(\t\x12\x0f\n\x07version\x18\x04 \x01(\t\"\xce\x01\n\x0b\x44\x65viceState\x12\x0e\n\x06\x64\x65vice\x18\x01 \x03(\t\x12\r\n\x05\x62uild\x18\x02 \x03(\t\x12\x19\n\x11\x62uild_incremental\x18\x03 \x01(\t\x12\x11\n\ttimestamp\x18\x04 \x01(\x03\x12\x11\n\tsdk_level\x18\x05 \x01(\t\x12\x1c\n\x14security_patch_level\x18\x06 \x01(\t\x12\x41\n\x0fpartition_state\x18\x07 \x03(\x0b\x32(.build.tools.releasetools.PartitionState\"c\n\x08\x41pexInfo\x12\x14\n\x0cpackage_name\x18\x01 \x01(\t\x12\x0f\n\x07version\x18\x02 \x01(\x03\x12\x15\n\ris_compressed\x18\x03 \x01(\x08\x12\x19\n\x11\x64\x65\x63ompressed_size\x18\x04 \x01(\x03\"E\n\x0c\x41pexMetadata\x12\x35\n\tapex_info\x18\x01 \x03(\x0b\x32\".build.tools.releasetools.ApexInfo\"\xf8\x03\n\x0bOtaMetadata\x12;\n\x04type\x18\x01 \x01(\x0e\x32-.build.tools.releasetools.OtaMetadata.OtaType\x12\x0c\n\x04wipe\x18\x02 \x01(\x08\x12\x11\n\tdowngrade\x18\x03 \x01(\x08\x12P\n\x0eproperty_files\x18\x04 \x03(\x0b\x32\x38.build.tools.releasetools.OtaMetadata.PropertyFilesEntry\x12;\n\x0cprecondition\x18\x05 \x01(\x0b\x32%.build.tools.releasetools.DeviceState\x12<\n\rpostcondition\x18\x06 \x01(\x0b\x32%.build.tools.releasetools.DeviceState\x12#\n\x1bretrofit_dynamic_partitions\x18\x07 \x01(\x08\x12\x16\n\x0erequired_cache\x18\x08 \x01(\x03\x12\x15\n\rspl_downgrade\x18\t \x01(\x08\x1a\x34\n\x12PropertyFilesEntry\x12\x0b\n\x03key\x18\x01 \x01(\t\x12\r\n\x05value\x18\x02 \x01(\t:\x02\x38\x01\"4\n\x07OtaType\x12\x0b\n\x07UNKNOWN\x10\x00\x12\x06\n\x02\x41\x42\x10\x01\x12\t\n\x05\x42LOCK\x10\x02\x12\t\n\x05\x42RICK\x10\x03\x42\x02H\x03\x62\x06proto3')
 )
 
 
@@ -29,33 +30,28 @@
   full_name='build.tools.releasetools.OtaMetadata.OtaType',
   filename=None,
   file=DESCRIPTOR,
-  create_key=_descriptor._internal_create_key,
   values=[
     _descriptor.EnumValueDescriptor(
       name='UNKNOWN', index=0, number=0,
       serialized_options=None,
-      type=None,
-      create_key=_descriptor._internal_create_key),
+      type=None),
     _descriptor.EnumValueDescriptor(
       name='AB', index=1, number=1,
       serialized_options=None,
-      type=None,
-      create_key=_descriptor._internal_create_key),
+      type=None),
     _descriptor.EnumValueDescriptor(
       name='BLOCK', index=2, number=2,
       serialized_options=None,
-      type=None,
-      create_key=_descriptor._internal_create_key),
+      type=None),
     _descriptor.EnumValueDescriptor(
       name='BRICK', index=3, number=3,
       serialized_options=None,
-      type=None,
-      create_key=_descriptor._internal_create_key),
+      type=None),
   ],
   containing_type=None,
   serialized_options=None,
-  serialized_start=1004,
-  serialized_end=1056,
+  serialized_start=972,
+  serialized_end=1024,
 )
 _sym_db.RegisterEnumDescriptor(_OTAMETADATA_OTATYPE)
 
@@ -66,36 +62,35 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
-  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='partition_name', full_name='build.tools.releasetools.PartitionState.partition_name', index=0,
       number=1, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=b"".decode('utf-8'),
+      has_default_value=False, default_value=_b("").decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='device', full_name='build.tools.releasetools.PartitionState.device', index=1,
       number=2, type=9, cpp_type=9, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='build', full_name='build.tools.releasetools.PartitionState.build', index=2,
       number=3, type=9, cpp_type=9, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='version', full_name='build.tools.releasetools.PartitionState.version', index=3,
       number=4, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=b"".decode('utf-8'),
+      has_default_value=False, default_value=_b("").decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
   ],
   extensions=[
   ],
@@ -119,7 +114,6 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
-  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='device', full_name='build.tools.releasetools.DeviceState.device', index=0,
@@ -127,49 +121,49 @@
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='build', full_name='build.tools.releasetools.DeviceState.build', index=1,
       number=2, type=9, cpp_type=9, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='build_incremental', full_name='build.tools.releasetools.DeviceState.build_incremental', index=2,
       number=3, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=b"".decode('utf-8'),
+      has_default_value=False, default_value=_b("").decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='timestamp', full_name='build.tools.releasetools.DeviceState.timestamp', index=3,
       number=4, type=3, cpp_type=2, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='sdk_level', full_name='build.tools.releasetools.DeviceState.sdk_level', index=4,
       number=5, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=b"".decode('utf-8'),
+      has_default_value=False, default_value=_b("").decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='security_patch_level', full_name='build.tools.releasetools.DeviceState.security_patch_level', index=5,
       number=6, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=b"".decode('utf-8'),
+      has_default_value=False, default_value=_b("").decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='partition_state', full_name='build.tools.releasetools.DeviceState.partition_state', index=6,
       number=7, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
   ],
   extensions=[
   ],
@@ -193,36 +187,35 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
-  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='package_name', full_name='build.tools.releasetools.ApexInfo.package_name', index=0,
       number=1, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=b"".decode('utf-8'),
+      has_default_value=False, default_value=_b("").decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='version', full_name='build.tools.releasetools.ApexInfo.version', index=1,
       number=2, type=3, cpp_type=2, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='is_compressed', full_name='build.tools.releasetools.ApexInfo.is_compressed', index=2,
       number=3, type=8, cpp_type=7, label=1,
       has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='decompressed_size', full_name='build.tools.releasetools.ApexInfo.decompressed_size', index=3,
       number=4, type=3, cpp_type=2, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
   ],
   extensions=[
   ],
@@ -246,7 +239,6 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
-  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='apex_info', full_name='build.tools.releasetools.ApexMetadata.apex_info', index=0,
@@ -254,7 +246,7 @@
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
   ],
   extensions=[
   ],
@@ -278,36 +270,35 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
-  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='key', full_name='build.tools.releasetools.OtaMetadata.PropertyFilesEntry.key', index=0,
       number=1, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=b"".decode('utf-8'),
+      has_default_value=False, default_value=_b("").decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='value', full_name='build.tools.releasetools.OtaMetadata.PropertyFilesEntry.value', index=1,
       number=2, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=b"".decode('utf-8'),
+      has_default_value=False, default_value=_b("").decode('utf-8'),
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
   ],
   extensions=[
   ],
   nested_types=[],
   enum_types=[
   ],
-  serialized_options=b'8\001',
+  serialized_options=_b('8\001'),
   is_extendable=False,
   syntax='proto3',
   extension_ranges=[],
   oneofs=[
   ],
-  serialized_start=950,
-  serialized_end=1002,
+  serialized_start=918,
+  serialized_end=970,
 )
 
 _OTAMETADATA = _descriptor.Descriptor(
@@ -316,7 +307,6 @@
   filename=None,
   file=DESCRIPTOR,
   containing_type=None,
-  create_key=_descriptor._internal_create_key,
   fields=[
     _descriptor.FieldDescriptor(
       name='type', full_name='build.tools.releasetools.OtaMetadata.type', index=0,
@@ -324,63 +314,63 @@
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='wipe', full_name='build.tools.releasetools.OtaMetadata.wipe', index=1,
       number=2, type=8, cpp_type=7, label=1,
       has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='downgrade', full_name='build.tools.releasetools.OtaMetadata.downgrade', index=2,
       number=3, type=8, cpp_type=7, label=1,
       has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='property_files', full_name='build.tools.releasetools.OtaMetadata.property_files', index=3,
       number=4, type=11, cpp_type=10, label=3,
       has_default_value=False, default_value=[],
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='precondition', full_name='build.tools.releasetools.OtaMetadata.precondition', index=4,
       number=5, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='postcondition', full_name='build.tools.releasetools.OtaMetadata.postcondition', index=5,
       number=6, type=11, cpp_type=10, label=1,
       has_default_value=False, default_value=None,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='retrofit_dynamic_partitions', full_name='build.tools.releasetools.OtaMetadata.retrofit_dynamic_partitions', index=6,
       number=7, type=8, cpp_type=7, label=1,
       has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
       name='required_cache', full_name='build.tools.releasetools.OtaMetadata.required_cache', index=7,
       number=8, type=3, cpp_type=2, label=1,
       has_default_value=False, default_value=0,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
     _descriptor.FieldDescriptor(
-      name='apex_info', full_name='build.tools.releasetools.OtaMetadata.apex_info', index=8,
-      number=9, type=11, cpp_type=10, label=3,
-      has_default_value=False, default_value=[],
+      name='spl_downgrade', full_name='build.tools.releasetools.OtaMetadata.spl_downgrade', index=8,
+      number=9, type=8, cpp_type=7, label=1,
+      has_default_value=False, default_value=False,
       message_type=None, enum_type=None, containing_type=None,
       is_extension=False, extension_scope=None,
-      serialized_options=None, file=DESCRIPTOR,  create_key=_descriptor._internal_create_key),
+      serialized_options=None, file=DESCRIPTOR),
   ],
   extensions=[
   ],
@@ -395,7 +385,7 @@
   oneofs=[
   ],
   serialized_start=520,
-  serialized_end=1056,
+  serialized_end=1024,
 )
 
 _DEVICESTATE.fields_by_name['partition_state'].message_type = _PARTITIONSTATE
@@ -405,7 +395,6 @@
 _OTAMETADATA.fields_by_name['property_files'].message_type = _OTAMETADATA_PROPERTYFILESENTRY
 _OTAMETADATA.fields_by_name['precondition'].message_type = _DEVICESTATE
 _OTAMETADATA.fields_by_name['postcondition'].message_type = _DEVICESTATE
-_OTAMETADATA.fields_by_name['apex_info'].message_type = _APEXINFO
 _OTAMETADATA_OTATYPE.containing_type = _OTAMETADATA
 DESCRIPTOR.message_types_by_name['PartitionState'] = _PARTITIONSTATE
 DESCRIPTOR.message_types_by_name['DeviceState'] = _DEVICESTATE
diff --git a/tools/releasetools/ota_utils.py b/tools/releasetools/ota_utils.py
index 6bbcc92..104f02f 100644
--- a/tools/releasetools/ota_utils.py
+++ b/tools/releasetools/ota_utils.py
@@ -39,6 +39,8 @@
 METADATA_NAME = 'META-INF/com/android/metadata'
 METADATA_PROTO_NAME = 'META-INF/com/android/metadata.pb'
 UNZIP_PATTERN = ['IMAGES/*', 'META/*', 'OTA/*', 'RADIO/*']
+SECURITY_PATCH_LEVEL_PROP_NAME = "ro.build.version.security_patch"
+
 
 def FinalizeMetadata(metadata, input_file, output_file, needed_property_files):
   """Finalizes the metadata and signs an A/B OTA package.
@@ -168,7 +170,7 @@
     build_info_set = ComputeRuntimeBuildInfos(build_info,
                                               boot_variable_values)
     assert "ab_partitions" in build_info.info_dict,\
-      "ab_partitions property required for ab update."
+        "ab_partitions property required for ab update."
     ab_partitions = set(build_info.info_dict.get("ab_partitions"))
 
     # delta_generator will error out on unused timestamps,
@@ -317,6 +319,8 @@
     metadata_dict['pre-build'] = separator.join(pre_build.build)
     metadata_dict['pre-build-incremental'] = pre_build.build_incremental
 
+  if metadata_proto.spl_downgrade:
+    metadata_dict['spl-downgrade'] = 'yes'
   metadata_dict.update(metadata_proto.property_files)
 
   return metadata_dict
@@ -330,6 +334,9 @@
   pre_timestamp = source_info.GetBuildProp("ro.build.date.utc")
   is_downgrade = int(post_timestamp) < int(pre_timestamp)
 
+  if OPTIONS.spl_downgrade:
+    metadata_proto.spl_downgrade = True
+
   if OPTIONS.downgrade:
     if not is_downgrade:
       raise RuntimeError(
diff --git a/tools/releasetools/sign_target_files_apks.py b/tools/releasetools/sign_target_files_apks.py
index 890cb51..05a085b 100755
--- a/tools/releasetools/sign_target_files_apks.py
+++ b/tools/releasetools/sign_target_files_apks.py
@@ -329,9 +329,8 @@
   """
   unknown_files = []
   for info in input_tf_zip.infolist():
-    # Handle APEXes first, e.g. SYSTEM/apex/com.android.tzdata.apex.
-    if (info.filename.startswith('SYSTEM/apex') and
-        info.filename.endswith('.apex')):
+    # Handle APEXes on all partitions
+    if info.filename.endswith('.apex'):
       name = os.path.basename(info.filename)
       if name not in known_keys:
         unknown_files.append(name)
@@ -363,8 +362,7 @@
 
   invalid_apexes = []
   for info in input_tf_zip.infolist():
-    if (not info.filename.startswith('SYSTEM/apex') or
-        not info.filename.endswith('.apex')):
+    if not info.filename.endswith('.apex'):
       continue
 
     name = os.path.basename(info.filename)
@@ -444,6 +442,7 @@
 
   return data
 
+
 def IsBuildPropFile(filename):
   return filename in (
         "SYSTEM/etc/prop.default",
@@ -462,6 +461,7 @@
         # path here for clarity.
         "RECOVERY/RAMDISK/default.prop") or filename.endswith("build.prop")
 
+
 def ProcessTargetFiles(input_tf_zip, output_tf_zip, misc_info,
                        apk_keys, apex_keys, key_passwords,
                        platform_api_level, codename_to_api_level_map,
@@ -514,8 +514,8 @@
             "        (skipped due to special cert string)" % (name,))
         common.ZipWriteStr(output_tf_zip, out_info, data)
 
-    # Sign bundled APEX files.
-    elif filename.startswith("SYSTEM/apex") and filename.endswith(".apex"):
+    # Sign bundled APEX files on all partitions
+    elif filename.endswith(".apex"):
       name = os.path.basename(filename)
       payload_key, container_key = apex_keys[name]
 
@@ -545,11 +545,6 @@
             "        (skipped due to special cert string)" % (name,))
         common.ZipWriteStr(output_tf_zip, out_info, data)
 
-    # AVB public keys for the installed APEXes, which will be updated later.
-    elif (os.path.dirname(filename) == 'SYSTEM/etc/security/apex' and
-          filename != 'SYSTEM/etc/security/apex/'):
-      continue
-
     # System properties.
     elif IsBuildPropFile(filename):
       print("Rewriting %s:" % (filename,))
diff --git a/tools/releasetools/test_merge_target_files.py b/tools/releasetools/test_merge_target_files.py
index 7ea7f96..072bb01 100644
--- a/tools/releasetools/test_merge_target_files.py
+++ b/tools/releasetools/test_merge_target_files.py
@@ -18,12 +18,11 @@
 
 import common
 import test_utils
-from merge_target_files import (validate_config_lists,
-                                DEFAULT_FRAMEWORK_ITEM_LIST,
-                                DEFAULT_VENDOR_ITEM_LIST,
-                                DEFAULT_FRAMEWORK_MISC_INFO_KEYS, copy_items,
-                                item_list_to_partition_set,
-                                process_apex_keys_apk_certs_common)
+from merge_target_files import (
+    validate_config_lists, DEFAULT_FRAMEWORK_ITEM_LIST,
+    DEFAULT_VENDOR_ITEM_LIST, DEFAULT_FRAMEWORK_MISC_INFO_KEYS, copy_items,
+    item_list_to_partition_set, process_apex_keys_apk_certs_common,
+    compile_split_sepolicy)
 
 
 class MergeTargetFilesTest(test_utils.ReleaseToolsTestCase):
@@ -235,3 +234,43 @@
     ]
     partition_set = item_list_to_partition_set(item_list)
     self.assertEqual(set(['product', 'system', 'system_ext']), partition_set)
+
+  def test_compile_split_sepolicy(self):
+    product_out_dir = common.MakeTempDir()
+
+    def write_temp_file(path, data=''):
+      full_path = os.path.join(product_out_dir, path)
+      if not os.path.exists(os.path.dirname(full_path)):
+        os.makedirs(os.path.dirname(full_path))
+      with open(full_path, 'w') as f:
+        f.write(data)
+
+    write_temp_file(
+        'system/etc/vintf/compatibility_matrix.device.xml', """
+      <compatibility-matrix>
+        <sepolicy>
+          <kernel-sepolicy-version>30</kernel-sepolicy-version>
+        </sepolicy>
+      </compatibility-matrix>""")
+    write_temp_file('vendor/etc/selinux/plat_sepolicy_vers.txt', '30.0')
+
+    write_temp_file('system/etc/selinux/plat_sepolicy.cil')
+    write_temp_file('system/etc/selinux/mapping/30.0.cil')
+    write_temp_file('product/etc/selinux/mapping/30.0.cil')
+    write_temp_file('vendor/etc/selinux/vendor_sepolicy.cil')
+    write_temp_file('vendor/etc/selinux/plat_pub_versioned.cil')
+
+    cmd = compile_split_sepolicy(product_out_dir, {
+        'system': 'system',
+        'product': 'product',
+        'vendor': 'vendor',
+    }, os.path.join(product_out_dir, 'policy'))
+    self.assertEqual(' '.join(cmd),
+                     ('secilc -m -M true -G -N -c 30 '
+                      '-o {OTP}/policy -f /dev/null '
+                      '{OTP}/system/etc/selinux/plat_sepolicy.cil '
+                      '{OTP}/system/etc/selinux/mapping/30.0.cil '
+                      '{OTP}/vendor/etc/selinux/vendor_sepolicy.cil '
+                      '{OTP}/vendor/etc/selinux/plat_pub_versioned.cil '
+                      '{OTP}/product/etc/selinux/mapping/30.0.cil').format(
+                          OTP=product_out_dir))
diff --git a/tools/releasetools/test_ota_from_target_files.py b/tools/releasetools/test_ota_from_target_files.py
index 8266908..9f64849 100644
--- a/tools/releasetools/test_ota_from_target_files.py
+++ b/tools/releasetools/test_ota_from_target_files.py
@@ -290,11 +290,11 @@
     self.assertEqual(apex_infos[0].is_compressed, True)
     # Compare the decompressed APEX size with the original uncompressed APEX
     original_apex_name = 'com.android.apex.compressed.v1_original.apex'
-    original_apex_filepath = os.path.join(test_utils.get_current_dir(), original_apex_name)
+    original_apex_filepath = os.path.join(
+        test_utils.get_current_dir(), original_apex_name)
     uncompressed_apex_size = os.path.getsize(original_apex_filepath)
     self.assertEqual(apex_infos[0].decompressed_size, uncompressed_apex_size)
 
-
   def test_GetPackageMetadata_retrofitDynamicPartitions(self):
     target_info = common.BuildInfo(self.TEST_TARGET_INFO_DICT, None)
     common.OPTIONS.retrofit_dynamic_partitions = True
@@ -343,7 +343,10 @@
     common.OPTIONS.incremental_source = ''
     common.OPTIONS.downgrade = True
     common.OPTIONS.wipe_user_data = True
+    common.OPTIONS.spl_downgrade = True
     metadata = self.GetLegacyOtaMetadata(target_info, source_info)
+    # Reset spl_downgrade so other tests are unaffected
+    common.OPTIONS.spl_downgrade = False
 
     self.assertDictEqual(
         {
@@ -359,6 +362,7 @@
             'pre-device': 'product-device',
             'pre-build': 'build-fingerprint-source',
             'pre-build-incremental': 'build-version-incremental-source',
+            'spl-downgrade': 'yes',
         },
         metadata)