Merge "releasetools: Don't return ZipFile from common.UnzipTemp()."
diff --git a/core/dex_preopt_libart_boot.mk b/core/dex_preopt_libart_boot.mk
index 134d1b6..a5e7e88 100644
--- a/core/dex_preopt_libart_boot.mk
+++ b/core/dex_preopt_libart_boot.mk
@@ -73,6 +73,23 @@
 # Note: this is technically incorrect. Compiled code contains stack checks which may depend
 #       on ASAN settings.
 
+# Use ANDROID_LOG_TAGS to suppress most logging by default...
+ifeq (,$(ART_BOOT_IMAGE_EXTRA_ARGS))
+DEX2OAT_BOOT_IMAGE_LOG_TAGS := ANDROID_LOG_TAGS="*:e"
+else
+# ...unless the boot image is generated specifically for testing, then allow all logging.
+DEX2OAT_BOOT_IMAGE_LOG_TAGS := ANDROID_LOG_TAGS="*:v"
+endif
+
+# An additional message to print on dex2oat failure.
+DEX2OAT_FAILURE_MESSAGE := ERROR: Dex2oat failed to compile a boot image.
+DEX2OAT_FAILURE_MESSAGE += It is likely that the boot classpath is inconsistent.
+ifeq ($(ONE_SHOT_MAKEFILE),)
+  DEX2OAT_FAILURE_MESSAGE += Rebuild with ART_BOOT_IMAGE_EXTRA_ARGS="--runtime-arg -verbose:verifier" to see verification errors.
+else
+  DEX2OAT_FAILURE_MESSAGE += Build with m, mma, or mmma instead of mm or mmm to remedy the situation.
+endif
+
 $($(my_2nd_arch_prefix)DEFAULT_DEX_PREOPT_BUILT_IMAGE_FILENAME): PRIVATE_BOOT_IMAGE_FLAGS := $(my_boot_image_flags)
 $($(my_2nd_arch_prefix)DEFAULT_DEX_PREOPT_BUILT_IMAGE_FILENAME): PRIVATE_2ND_ARCH_VAR_PREFIX := $(my_2nd_arch_prefix)
 $($(my_2nd_arch_prefix)DEFAULT_DEX_PREOPT_BUILT_IMAGE_FILENAME): PRIVATE_IMAGE_LOCATION := $($(my_2nd_arch_prefix)DEFAULT_DEX_PREOPT_BUILT_IMAGE_LOCATION)
@@ -85,7 +102,7 @@
 	@rm -f $(dir $($(PRIVATE_2ND_ARCH_VAR_PREFIX)LIBART_TARGET_BOOT_OAT_UNSTRIPPED))/*.art
 	@rm -f $(dir $($(PRIVATE_2ND_ARCH_VAR_PREFIX)LIBART_TARGET_BOOT_OAT_UNSTRIPPED))/*.oat
 	@rm -f $(dir $($(PRIVATE_2ND_ARCH_VAR_PREFIX)LIBART_TARGET_BOOT_OAT_UNSTRIPPED))/*.art.rel
-	$(hide) ANDROID_LOG_TAGS="*:e" $(DEX2OAT) --runtime-arg -Xms$(DEX2OAT_IMAGE_XMS) \
+	$(hide) $(DEX2OAT_BOOT_IMAGE_LOG_TAGS) $(DEX2OAT) --runtime-arg -Xms$(DEX2OAT_IMAGE_XMS) \
 		--runtime-arg -Xmx$(DEX2OAT_IMAGE_XMX) \
 		$(PRIVATE_BOOT_IMAGE_FLAGS) \
 		$(addprefix --dex-file=,$(LIBART_TARGET_BOOT_DEX_FILES)) \
@@ -103,8 +120,9 @@
 		--multi-image --no-inline-from=core-oj.jar \
 		--abort-on-hard-verifier-error \
 		--abort-on-soft-verifier-error \
-		$(PRODUCT_DEX_PREOPT_BOOT_FLAGS) $(GLOBAL_DEXPREOPT_FLAGS) $(ART_BOOT_IMAGE_EXTRA_ARGS) && \
-	ANDROID_LOG_TAGS="*:e" ANDROID_ROOT=$(PRODUCT_OUT)/system ANDROID_DATA=$(dir $@) $(PATCHOAT) \
+		$(PRODUCT_DEX_PREOPT_BOOT_FLAGS) $(GLOBAL_DEXPREOPT_FLAGS) $(ART_BOOT_IMAGE_EXTRA_ARGS) \
+		|| ( echo "$(DEX2OAT_FAILURE_MESSAGE)" ; false ) && \
+	$(DEX2OAT_BOOT_IMAGE_LOG_TAGS) ANDROID_ROOT=$(PRODUCT_OUT)/system ANDROID_DATA=$(dir $@) $(PATCHOAT) \
 		--input-image-location=$(PRIVATE_IMAGE_LOCATION) \
 		--output-image-relocation-directory=$(dir $@) \
 		--instruction-set=$($(PRIVATE_2ND_ARCH_VAR_PREFIX)DEX2OAT_TARGET_ARCH) \