diff --git a/Android.bp b/Android.bp
new file mode 100644
index 0000000..376c250
--- /dev/null
+++ b/Android.bp
@@ -0,0 +1,52 @@
+//
+// Copyright (C) 2019 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.
+//
+
+bionic_mountpoint {
+    name: "libc.mountpoint",
+    stem: "libc.so",
+    src: "dummy_mountpoint",
+    library: true,
+    symlinks: ["libc.so"],
+}
+
+bionic_mountpoint {
+    name: "libdl.mountpoint",
+    stem: "libdl.so",
+    src: "dummy_mountpoint",
+    library: true,
+    symlinks: ["libdl.so"],
+}
+
+bionic_mountpoint {
+    name: "libm.mountpoint",
+    stem: "libm.so",
+    src: "dummy_mountpoint",
+    library: true,
+    symlinks: ["libm.so"],
+}
+
+bionic_mountpoint {
+    name: "linker.mountpoint",
+    stem: "linker",
+    multilib: {
+        lib64: {
+            suffix: "64",
+        },
+    },
+    src: "dummy_mountpoint",
+    binary: true,
+    symlinks: ["linker", "linker_asan"],
+}
diff --git a/build/Android.bp b/build/Android.bp
new file mode 100644
index 0000000..6cc160a
--- /dev/null
+++ b/build/Android.bp
@@ -0,0 +1,32 @@
+//
+// Copyright (C) 2019 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.
+//
+
+
+bootstrap_go_package {
+    name: "soong-bionic",
+    pkgPath: "android/soong/bionic",
+    deps: [
+        "blueprint",
+        "blueprint-pathtools",
+        "blueprint-proptools",
+        "soong",
+        "soong-android",
+    ],
+    srcs: [
+        "bionic.go",
+    ],
+    pluginFor: ["soong_build"],
+}
diff --git a/build/bionic.go b/build/bionic.go
new file mode 100644
index 0000000..3522aca
--- /dev/null
+++ b/build/bionic.go
@@ -0,0 +1,164 @@
+// Copyright (C) 2019 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 bionic
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/google/blueprint/proptools"
+
+	"android/soong/android"
+)
+
+// bionic_mountpoint is a module type that is specialized to create
+// mount points for Bionic files (libc, libdl, libm, and linker).
+//
+// With following description,
+//
+// bionic_mountpoint {
+//    name: "libc.mountpoint",
+//    stem: "libc.so",
+//    src: "dummy_mountpoint",
+//    library: true,
+//    symlinks: ["libc.so"],
+// }
+//
+// , the build system does following jobs:
+//
+// A mount point /bionic/lib[64]/libc.so is created. Its content
+// is from the file 'dummy_mountpoint'.
+//
+// Then a symlink is created at /system/lib[64]/libc.so which points to
+// the created mountpoint.
+//
+// At runtime, on the mount point, either bootstrap Bionic or default Bionic
+// (which is from the runtime APEX) is mounted by the init process. The
+// symlink exists to provide consistent legacy path for compatibility
+// reason.
+func init() {
+	android.RegisterModuleType("bionic_mountpoint", bionicMountpointFactory)
+}
+
+type bionicMountpoint struct {
+	android.ModuleBase
+	properties bionicMountpointProperties
+
+	outputFile android.Path
+	pathInPartition string
+	stem string
+}
+
+type bionicMountpointProperties struct {
+	// The file that is installed as the mount point
+	Src *string
+
+	// True if the mount point is for a Bionic library such libc.so
+	Library *bool
+	// True if the mount point is for a Bionic binary such as linker
+	Binary *bool
+
+	// Base name of the mount point
+	Stem *string `android:"arch_variant"`
+
+	// Append to the name of the output
+	Suffix *string `android:"arch_variant"`
+
+	// Symlinks to the mountpoints from the system and recovery partitions
+	// Symlinks names will have the same suffix as the mount point
+	Symlinks []string
+}
+
+func (m *bionicMountpoint) DepsMutator(ctx android.BottomUpMutatorContext) {
+	if Bool(m.properties.Library) == Bool(m.properties.Binary) {
+		ctx.ModuleErrorf("either binary or library must be set to true")
+		return
+	}
+	if m.properties.Stem == nil {
+		ctx.PropertyErrorf("stem", "stem must be set")
+		return
+	}
+	if m.properties.Src == nil {
+		ctx.PropertyErrorf("src", "src must be set")
+	}
+	android.ExtractSourceDeps(ctx, m.properties.Src)
+}
+
+func (m *bionicMountpoint) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	if Bool(m.properties.Library) {
+		m.pathInPartition = "lib"
+		if m.Arch().ArchType.Multilib == "lib64" {
+			m.pathInPartition = "lib64"
+		}
+	} else if Bool(m.properties.Binary) {
+		m.pathInPartition = "bin"
+	}
+
+	m.stem = String(m.properties.Stem) + String(m.properties.Suffix)
+
+	m.outputFile = ctx.ExpandSource(String(m.properties.Src), "src")
+}
+
+func (m *bionicMountpoint) AndroidMk() android.AndroidMkData {
+	return android.AndroidMkData {
+		Custom: func(w io.Writer, name, prefix, moduleDir string, data android.AndroidMkData) {
+			if !m.Arch().Native {
+				return
+			}
+			fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)")
+			fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
+			fmt.Fprintln(w, "LOCAL_MODULE :=", name)
+			fmt.Fprintln(w, "LOCAL_USE_CLANG_LLD := false")
+			fmt.Fprintln(w, "LOCAL_STRIP_MODULE := false")
+			if Bool(m.properties.Library) {
+				fmt.Fprintln(w, "LOCAL_MODULE_CLASS := SHARED_LIBRARIES")
+			} else if Bool(m.properties.Binary) {
+				fmt.Fprintln(w, "LOCAL_MODULE_CLASS := EXECUTABLES")
+			}
+			fmt.Fprintln(w, "LOCAL_MODULE_TAGS := optional")
+			fmt.Fprintln(w, "LOCAL_PREBUILT_MODULE_FILE :=", m.outputFile.String())
+			fmt.Fprintln(w, "LOCAL_MODULE_TARGET_ARCH :=", m.Arch().ArchType.String())
+			fmt.Fprintln(w, "LOCAL_MODULE_PATH :=", "$(TARGET_ROOT_OUT)/bionic/" + m.pathInPartition)
+			fmt.Fprintln(w, "LOCAL_INSTALLED_MODULE_STEM :=", m.stem)
+
+			if len(m.properties.Symlinks) > 0 {
+				symlink_dir_in_system := "$(TARGET_OUT)/" + m.pathInPartition + "/"
+				symlink_dir_in_recovery := "$(TARGET_RECOVERY_ROOT_OUT)/system/" + m.pathInPartition + "/"
+				symlink_target := "/bionic/" + m.pathInPartition + "/" + m.stem
+				cmds := []string{}
+				cmds = append(cmds, "$(hide) mkdir -p " + symlink_dir_in_system)
+				cmds = append(cmds, "mkdir -p " + symlink_dir_in_recovery)
+				for _, s := range m.properties.Symlinks {
+					symlink := s + String(m.properties.Suffix)
+					cmds = append(cmds, "ln -sf " + symlink_target + " " + symlink_dir_in_system +  symlink)
+					cmds = append(cmds, "ln -sf " + symlink_target + " " + symlink_dir_in_recovery +  symlink)
+				}
+				fmt.Fprintln(w, "LOCAL_POST_INSTALL_CMD := " + strings.Join(cmds, " && "))
+			}
+			fmt.Fprintln(w, "include $(BUILD_PREBUILT)")
+		},
+	}
+}
+
+func bionicMountpointFactory() android.Module {
+	m := &bionicMountpoint{}
+        m.AddProperties(&m.properties)
+	android.InitAndroidArchModule(m, android.DeviceSupported, android.MultilibBoth)
+	return m
+}
+
+var Bool = proptools.Bool
+var String = proptools.String
diff --git a/dummy_mountpoint b/dummy_mountpoint
new file mode 100644
index 0000000..2d13c55
--- /dev/null
+++ b/dummy_mountpoint
@@ -0,0 +1 @@
+This file serves as a mount point for bionic files either from /system partition or from /apex/com.android.runtime. This file is never meant to be accessed directly.
diff --git a/libc/Android.bp b/libc/Android.bp
index 226a81f..dc437d8 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -328,13 +328,10 @@
         "upstream-netbsd/lib/libc/regex/regexec.c",
         "upstream-netbsd/lib/libc/regex/regfree.c",
         "upstream-netbsd/lib/libc/stdlib/bsearch.c",
-        "upstream-netbsd/lib/libc/stdlib/div.c",
         "upstream-netbsd/lib/libc/stdlib/drand48.c",
         "upstream-netbsd/lib/libc/stdlib/erand48.c",
         "upstream-netbsd/lib/libc/stdlib/jrand48.c",
         "upstream-netbsd/lib/libc/stdlib/lcong48.c",
-        "upstream-netbsd/lib/libc/stdlib/ldiv.c",
-        "upstream-netbsd/lib/libc/stdlib/lldiv.c",
         "upstream-netbsd/lib/libc/stdlib/lrand48.c",
         "upstream-netbsd/lib/libc/stdlib/mrand48.c",
         "upstream-netbsd/lib/libc/stdlib/nrand48.c",
@@ -343,10 +340,6 @@
         "upstream-netbsd/lib/libc/stdlib/reallocarr.c",
         "upstream-netbsd/lib/libc/stdlib/seed48.c",
         "upstream-netbsd/lib/libc/stdlib/srand48.c",
-        "upstream-netbsd/lib/libc/string/memccpy.c",
-        "upstream-netbsd/lib/libc/string/strcasestr.c",
-        "upstream-netbsd/lib/libc/string/strcoll.c",
-        "upstream-netbsd/lib/libc/string/strxfrm.c",
     ],
     multilib: {
         lib32: {
@@ -456,19 +449,25 @@
         "upstream-openbsd/lib/libc/stdio/wbuf.c",
         "upstream-openbsd/lib/libc/stdio/wsetup.c",
         "upstream-openbsd/lib/libc/stdlib/abs.c",
+        "upstream-openbsd/lib/libc/stdlib/div.c",
         "upstream-openbsd/lib/libc/stdlib/getenv.c",
         "upstream-openbsd/lib/libc/stdlib/getsubopt.c",
         "upstream-openbsd/lib/libc/stdlib/insque.c",
         "upstream-openbsd/lib/libc/stdlib/imaxabs.c",
         "upstream-openbsd/lib/libc/stdlib/imaxdiv.c",
         "upstream-openbsd/lib/libc/stdlib/labs.c",
+        "upstream-openbsd/lib/libc/stdlib/ldiv.c",
         "upstream-openbsd/lib/libc/stdlib/llabs.c",
+        "upstream-openbsd/lib/libc/stdlib/lldiv.c",
         "upstream-openbsd/lib/libc/stdlib/lsearch.c",
         "upstream-openbsd/lib/libc/stdlib/remque.c",
         "upstream-openbsd/lib/libc/stdlib/setenv.c",
         "upstream-openbsd/lib/libc/stdlib/tfind.c",
         "upstream-openbsd/lib/libc/stdlib/tsearch.c",
+        "upstream-openbsd/lib/libc/string/memccpy.c",
         "upstream-openbsd/lib/libc/string/strcasecmp.c",
+        "upstream-openbsd/lib/libc/string/strcasestr.c",
+        "upstream-openbsd/lib/libc/string/strcoll.c",
         "upstream-openbsd/lib/libc/string/strcspn.c",
         "upstream-openbsd/lib/libc/string/strdup.c",
         "upstream-openbsd/lib/libc/string/strndup.c",
@@ -477,6 +476,7 @@
         "upstream-openbsd/lib/libc/string/strspn.c",
         "upstream-openbsd/lib/libc/string/strstr.c",
         "upstream-openbsd/lib/libc/string/strtok.c",
+        "upstream-openbsd/lib/libc/string/strxfrm.c",
         "upstream-openbsd/lib/libc/string/wcslcpy.c",
         "upstream-openbsd/lib/libc/string/wcswidth.c",
     ],
@@ -1548,7 +1548,7 @@
         ],
     },
 
-    required: ["tzdata"],
+    required: ["tzdata", "libc.mountpoint"],
 
     // Leave the symbols in the shared library so that stack unwinders can produce
     // meaningful name resolution.
diff --git a/libc/bionic/libc_init_static.cpp b/libc/bionic/libc_init_static.cpp
index 514423d..3219239 100644
--- a/libc/bionic/libc_init_static.cpp
+++ b/libc/bionic/libc_init_static.cpp
@@ -66,6 +66,30 @@
   }
 }
 
+#if defined(__aarch64__) || defined(__x86_64__)
+extern __LIBC_HIDDEN__ ElfW(Rela) __rela_iplt_start[], __rela_iplt_end[];
+
+static void call_ifunc_resolvers() {
+  typedef ElfW(Addr) (*ifunc_resolver_t)(void);
+  for (ElfW(Rela) *r = __rela_iplt_start; r != __rela_iplt_end; ++r) {
+    ElfW(Addr)* offset = reinterpret_cast<ElfW(Addr)*>(r->r_offset);
+    ElfW(Addr) resolver = r->r_addend;
+    *offset = reinterpret_cast<ifunc_resolver_t>(resolver)();
+  }
+}
+#else
+extern __LIBC_HIDDEN__ ElfW(Rel) __rel_iplt_start[], __rel_iplt_end[];
+
+static void call_ifunc_resolvers() {
+  typedef ElfW(Addr) (*ifunc_resolver_t)(void);
+  for (ElfW(Rel) *r = __rel_iplt_start; r != __rel_iplt_end; ++r) {
+    ElfW(Addr)* offset = reinterpret_cast<ElfW(Addr)*>(r->r_offset);
+    ElfW(Addr) resolver = *offset;
+    *offset = reinterpret_cast<ifunc_resolver_t>(resolver)();
+  }
+}
+#endif
+
 static void apply_gnu_relro() {
   ElfW(Phdr)* phdr_start = reinterpret_cast<ElfW(Phdr)*>(getauxval(AT_PHDR));
   unsigned long int phdr_ct = getauxval(AT_PHNUM);
@@ -137,6 +161,7 @@
   __libc_init_main_thread_final();
   __libc_init_common();
 
+  call_ifunc_resolvers();
   apply_gnu_relro();
 
   // Several Linux ABIs don't pass the onexit pointer, and the ones that
diff --git a/libc/bionic/malloc_common.cpp b/libc/bionic/malloc_common.cpp
index fc65e15..50c2fec 100644
--- a/libc/bionic/malloc_common.cpp
+++ b/libc/bionic/malloc_common.cpp
@@ -604,9 +604,8 @@
   return impl_handle;
 }
 
-// A function pointer to heapprofds init function. Used to re-initialize
-// heapprofd. This will start a new profiling session and tear down the old
-// one in case it is still active.
+// The handle returned by dlopen when previously loading the heapprofd
+// hooks. nullptr if they had not been loaded before.
 static _Atomic (void*) g_heapprofd_handle = nullptr;
 
 static void install_hooks(libc_globals* globals, const char* options,
@@ -614,7 +613,8 @@
   MallocDispatch dispatch_table;
 
   void* impl_handle = atomic_load(&g_heapprofd_handle);
-  if (impl_handle != nullptr) {
+  bool reusing_handle = impl_handle != nullptr;
+  if (reusing_handle) {
     if (!InitSharedLibrary(impl_handle, shared_lib, prefix, &dispatch_table)) {
       return;
     }
@@ -627,7 +627,11 @@
   init_func_t init_func = reinterpret_cast<init_func_t>(g_functions[FUNC_INITIALIZE]);
   if (!init_func(&__libc_malloc_default_dispatch, &gMallocLeakZygoteChild, options)) {
     error_log("%s: failed to enable malloc %s", getprogname(), prefix);
-    dlclose(impl_handle);
+    if (!reusing_handle) {
+      // We should not close if we are re-using an old handle, as we cannot be
+      // sure other threads are not currently in the hooks.
+      dlclose(impl_handle);
+    }
     ClearGlobalFunctions();
     return;
   }
diff --git a/libc/bionic/pthread_detach.cpp b/libc/bionic/pthread_detach.cpp
index c2e4127..6b22039 100644
--- a/libc/bionic/pthread_detach.cpp
+++ b/libc/bionic/pthread_detach.cpp
@@ -34,7 +34,7 @@
 
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
 int pthread_detach(pthread_t t) {
-  pthread_internal_t* thread = __pthread_internal_find(t);
+  pthread_internal_t* thread = __pthread_internal_find(t, "pthread_detach");
   if (thread == nullptr) {
     return ESRCH;
   }
diff --git a/libc/bionic/pthread_getcpuclockid.cpp b/libc/bionic/pthread_getcpuclockid.cpp
index f641e4c..0b35998 100644
--- a/libc/bionic/pthread_getcpuclockid.cpp
+++ b/libc/bionic/pthread_getcpuclockid.cpp
@@ -31,7 +31,7 @@
 #include "pthread_internal.h"
 
 int pthread_getcpuclockid(pthread_t t, clockid_t* clockid) {
-  pid_t tid = pthread_gettid_np(t);
+  pid_t tid = __pthread_internal_gettid(t, "pthread_getcpuclockid");
   if (tid == -1) return ESRCH;
 
   // The tid is stored in the top bits, but negated.
diff --git a/libc/bionic/pthread_getschedparam.cpp b/libc/bionic/pthread_getschedparam.cpp
index cc1ece8..ed1853b 100644
--- a/libc/bionic/pthread_getschedparam.cpp
+++ b/libc/bionic/pthread_getschedparam.cpp
@@ -34,7 +34,7 @@
 int pthread_getschedparam(pthread_t t, int* policy, sched_param* param) {
   ErrnoRestorer errno_restorer;
 
-  pid_t tid = pthread_gettid_np(t);
+  pid_t tid = __pthread_internal_gettid(t, "pthread_getschedparam");
   if (tid == -1) return ESRCH;
 
   if (sched_getparam(tid, param) == -1) return errno;
diff --git a/libc/bionic/pthread_gettid_np.cpp b/libc/bionic/pthread_gettid_np.cpp
index 1beddc9..d14900b 100644
--- a/libc/bionic/pthread_gettid_np.cpp
+++ b/libc/bionic/pthread_gettid_np.cpp
@@ -31,6 +31,5 @@
 
 __BIONIC_WEAK_FOR_NATIVE_BRIDGE
 pid_t pthread_gettid_np(pthread_t t) {
-  pthread_internal_t* thread = __pthread_internal_find(t);
-  return thread ? thread->tid : -1;
+  return __pthread_internal_gettid(t, "pthread_gettid_np");
 }
diff --git a/libc/bionic/pthread_internal.cpp b/libc/bionic/pthread_internal.cpp
index 46fa630..6fddefe 100644
--- a/libc/bionic/pthread_internal.cpp
+++ b/libc/bionic/pthread_internal.cpp
@@ -80,7 +80,12 @@
   __pthread_internal_free(thread);
 }
 
-pthread_internal_t* __pthread_internal_find(pthread_t thread_id) {
+pid_t __pthread_internal_gettid(pthread_t thread_id, const char* caller) {
+  pthread_internal_t* thread = __pthread_internal_find(thread_id, caller);
+  return thread ? thread->tid : -1;
+}
+
+pthread_internal_t* __pthread_internal_find(pthread_t thread_id, const char* caller) {
   pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(thread_id);
 
   // Check if we're looking for ourselves before acquiring the lock.
@@ -103,9 +108,9 @@
       // addresses might sometimes contain threads or things that look enough like
       // threads for us to do some real damage by continuing.
       // TODO: try getting rid of this when Treble lets us keep vendor blobs on an old API level.
-      async_safe_format_log(ANDROID_LOG_WARN, "libc", "invalid pthread_t (0) passed to libc");
+      async_safe_format_log(ANDROID_LOG_WARN, "libc", "invalid pthread_t (0) passed to %s", caller);
     } else {
-      async_safe_fatal("invalid pthread_t %p passed to libc", thread);
+      async_safe_fatal("invalid pthread_t %p passed to %s", thread, caller);
     }
   }
   return nullptr;
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index cbcdadf..a1e0c45 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -163,10 +163,11 @@
 __LIBC_HIDDEN__ int __init_thread(pthread_internal_t* thread);
 __LIBC_HIDDEN__ ThreadMapping __allocate_thread_mapping(size_t stack_size, size_t stack_guard_size);
 
-__LIBC_HIDDEN__ pthread_t           __pthread_internal_add(pthread_internal_t* thread);
-__LIBC_HIDDEN__ pthread_internal_t* __pthread_internal_find(pthread_t pthread_id);
-__LIBC_HIDDEN__ void                __pthread_internal_remove(pthread_internal_t* thread);
-__LIBC_HIDDEN__ void                __pthread_internal_remove_and_free(pthread_internal_t* thread);
+__LIBC_HIDDEN__ pthread_t __pthread_internal_add(pthread_internal_t* thread);
+__LIBC_HIDDEN__ pthread_internal_t* __pthread_internal_find(pthread_t pthread_id, const char* caller);
+__LIBC_HIDDEN__ pid_t __pthread_internal_gettid(pthread_t pthread_id, const char* caller);
+__LIBC_HIDDEN__ void __pthread_internal_remove(pthread_internal_t* thread);
+__LIBC_HIDDEN__ void __pthread_internal_remove_and_free(pthread_internal_t* thread);
 
 static inline __always_inline bionic_tcb* __get_bionic_tcb() {
   return reinterpret_cast<bionic_tcb*>(&__get_tls()[MIN_TLS_SLOT]);
diff --git a/libc/bionic/pthread_join.cpp b/libc/bionic/pthread_join.cpp
index 8e4ca59..e230fab 100644
--- a/libc/bionic/pthread_join.cpp
+++ b/libc/bionic/pthread_join.cpp
@@ -40,7 +40,7 @@
     return EDEADLK;
   }
 
-  pthread_internal_t* thread = __pthread_internal_find(t);
+  pthread_internal_t* thread = __pthread_internal_find(t, "pthread_join");
   if (thread == nullptr) {
     return ESRCH;
   }
diff --git a/libc/bionic/pthread_kill.cpp b/libc/bionic/pthread_kill.cpp
index 1531574..8b38f4c 100644
--- a/libc/bionic/pthread_kill.cpp
+++ b/libc/bionic/pthread_kill.cpp
@@ -35,7 +35,7 @@
 int pthread_kill(pthread_t t, int sig) {
   ErrnoRestorer errno_restorer;
 
-  pid_t tid = pthread_gettid_np(t);
+  pid_t tid = __pthread_internal_gettid(t, "pthread_kill");
 
   // tid gets reset to 0 on thread exit by CLONE_CHILD_CLEARTID.
   if (tid == 0 || tid == -1) return ESRCH;
diff --git a/libc/bionic/pthread_setname_np.cpp b/libc/bionic/pthread_setname_np.cpp
index f582d53..f673983 100644
--- a/libc/bionic/pthread_setname_np.cpp
+++ b/libc/bionic/pthread_setname_np.cpp
@@ -42,9 +42,10 @@
 // This value is not exported by kernel headers.
 #define MAX_TASK_COMM_LEN 16
 
-static int __open_task_comm_fd(pthread_t t, int flags) {
+static int __open_task_comm_fd(pthread_t t, int flags, const char* caller) {
   char comm_name[64];
-  snprintf(comm_name, sizeof(comm_name), "/proc/self/task/%d/comm", pthread_gettid_np(t));
+  snprintf(comm_name, sizeof(comm_name), "/proc/self/task/%d/comm",
+           __pthread_internal_gettid(t, caller));
   return open(comm_name, O_CLOEXEC | flags);
 }
 
@@ -59,7 +60,7 @@
   }
 
   // We have to get another thread's name.
-  int fd = __open_task_comm_fd(t, O_RDONLY);
+  int fd = __open_task_comm_fd(t, O_RDONLY, "pthread_getname_np");
   if (fd == -1) return errno;
 
   ssize_t n = TEMP_FAILURE_RETRY(read(fd, buf, buf_size));
@@ -91,7 +92,7 @@
   }
 
   // We have to set another thread's name.
-  int fd = __open_task_comm_fd(t, O_WRONLY);
+  int fd = __open_task_comm_fd(t, O_WRONLY, "pthread_setname_np");
   if (fd == -1) return errno;
 
   ssize_t n = TEMP_FAILURE_RETRY(write(fd, thread_name, thread_name_len));
diff --git a/libc/bionic/pthread_setschedparam.cpp b/libc/bionic/pthread_setschedparam.cpp
index 10826d1..8a02728 100644
--- a/libc/bionic/pthread_setschedparam.cpp
+++ b/libc/bionic/pthread_setschedparam.cpp
@@ -31,11 +31,12 @@
 #include <sched.h>
 
 #include "private/ErrnoRestorer.h"
+#include "pthread_internal.h"
 
 int pthread_setschedparam(pthread_t t, int policy, const sched_param* param) {
   ErrnoRestorer errno_restorer;
 
-  pid_t tid = pthread_gettid_np(t);
+  pid_t tid = __pthread_internal_gettid(t, "pthread_setschedparam");
   if (tid == -1) return ESRCH;
 
   return (sched_setscheduler(tid, policy, param) == -1) ? errno : 0;
@@ -44,7 +45,7 @@
 int pthread_setschedprio(pthread_t t, int priority) {
   ErrnoRestorer errno_restorer;
 
-  pid_t tid = pthread_gettid_np(t);
+  pid_t tid = __pthread_internal_gettid(t, "pthread_setschedprio");
   if (tid == -1) return ESRCH;
 
   sched_param param = { .sched_priority = priority };
diff --git a/libc/bionic/pthread_sigqueue.cpp b/libc/bionic/pthread_sigqueue.cpp
index 34bda38..5d13ed5 100644
--- a/libc/bionic/pthread_sigqueue.cpp
+++ b/libc/bionic/pthread_sigqueue.cpp
@@ -38,7 +38,7 @@
 int pthread_sigqueue(pthread_t t, int sig, const union sigval value) {
   ErrnoRestorer errno_restorer;
 
-  pid_t tid = pthread_gettid_np(t);
+  pid_t tid = __pthread_internal_gettid(t, "pthread_sigqueue");
   if (tid == -1) return ESRCH;
 
   siginfo_t siginfo;
diff --git a/libc/stdio/fmemopen.cpp b/libc/stdio/fmemopen.cpp
index 9d8c41f..6e333ba 100644
--- a/libc/stdio/fmemopen.cpp
+++ b/libc/stdio/fmemopen.cpp
@@ -149,7 +149,9 @@
   } else if (mode[0] == 'w') {
     ck->size = 0;
     ck->offset = 0;
-    ck->buf[0] = '\0';
+    if (capacity > 0) {
+      ck->buf[0] = '\0';
+    }
   }
 
   return fp;
diff --git a/libc/upstream-netbsd/lib/libc/stdlib/lldiv.c b/libc/upstream-netbsd/lib/libc/stdlib/lldiv.c
deleted file mode 100644
index 47104b3..0000000
--- a/libc/upstream-netbsd/lib/libc/stdlib/lldiv.c
+++ /dev/null
@@ -1,66 +0,0 @@
-/*	$NetBSD: lldiv.c,v 1.4 2012/06/25 22:32:45 abs Exp $	*/
-
-/*
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * Chris Torek.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- * 3. Neither the name of the University nor the names of its contributors
- *    may be used to endorse or promote products derived from this software
- *    without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "from: @(#)ldiv.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: lldiv.c,v 1.4 2012/06/25 22:32:45 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
-#include "namespace.h"
-#include <stdlib.h>		/* lldiv_t */
-
-#ifdef __weak_alias
-__weak_alias(lldiv, _lldiv)
-#endif
-
-/* LONGLONG */
-lldiv_t
-lldiv(long long int num, long long int denom)
-{
-	lldiv_t r;
-
-	/* see div.c for comments */
-
-	r.quot = num / denom;
-	r.rem = num % denom;
-	if (num >= 0 && r.rem < 0) {
-		r.quot++;
-		r.rem -= denom;
-	}
-	return (r);
-}
diff --git a/libc/upstream-netbsd/lib/libc/stdlib/div.c b/libc/upstream-openbsd/lib/libc/stdlib/div.c
similarity index 86%
rename from libc/upstream-netbsd/lib/libc/stdlib/div.c
rename to libc/upstream-openbsd/lib/libc/stdlib/div.c
index f3bd32f..beaa428 100644
--- a/libc/upstream-netbsd/lib/libc/stdlib/div.c
+++ b/libc/upstream-openbsd/lib/libc/stdlib/div.c
@@ -1,8 +1,7 @@
-/*	$NetBSD: div.c,v 1.8 2012/06/25 22:32:45 abs Exp $	*/
-
+/*	$OpenBSD: div.c,v 1.6 2015/09/13 08:31:47 guenther Exp $ */
 /*
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1990 Regents of the University of California.
+ * All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
@@ -32,15 +31,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)div.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: div.c,v 1.8 2012/06/25 22:32:45 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
 #include <stdlib.h>		/* div_t */
 
 div_t
@@ -79,3 +69,4 @@
 	}
 	return (r);
 }
+DEF_STRONG(div);
diff --git a/libc/upstream-netbsd/lib/libc/stdlib/ldiv.c b/libc/upstream-openbsd/lib/libc/stdlib/ldiv.c
similarity index 81%
rename from libc/upstream-netbsd/lib/libc/stdlib/ldiv.c
rename to libc/upstream-openbsd/lib/libc/stdlib/ldiv.c
index 507c831..775065f 100644
--- a/libc/upstream-netbsd/lib/libc/stdlib/ldiv.c
+++ b/libc/upstream-openbsd/lib/libc/stdlib/ldiv.c
@@ -1,8 +1,7 @@
-/*	$NetBSD: ldiv.c,v 1.8 2012/06/25 22:32:45 abs Exp $	*/
-
+/*	$OpenBSD: ldiv.c,v 1.5 2005/08/08 08:05:36 espie Exp $ */
 /*
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1990 Regents of the University of California.
+ * All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
@@ -32,15 +31,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)ldiv.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: ldiv.c,v 1.8 2012/06/25 22:32:45 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
 #include <stdlib.h>		/* ldiv_t */
 
 ldiv_t
diff --git a/libc/upstream-netbsd/lib/libc/stdlib/ldiv.c b/libc/upstream-openbsd/lib/libc/stdlib/lldiv.c
similarity index 78%
copy from libc/upstream-netbsd/lib/libc/stdlib/ldiv.c
copy to libc/upstream-openbsd/lib/libc/stdlib/lldiv.c
index 507c831..59c37b8 100644
--- a/libc/upstream-netbsd/lib/libc/stdlib/ldiv.c
+++ b/libc/upstream-openbsd/lib/libc/stdlib/lldiv.c
@@ -1,8 +1,7 @@
-/*	$NetBSD: ldiv.c,v 1.8 2012/06/25 22:32:45 abs Exp $	*/
-
+/*	$OpenBSD: lldiv.c,v 1.2 2016/08/14 23:18:03 guenther Exp $	*/
 /*
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1990 Regents of the University of California.
+ * All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
@@ -32,21 +31,12 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)ldiv.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: ldiv.c,v 1.8 2012/06/25 22:32:45 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
+#include <stdlib.h>		/* lldiv_t */
 
-#include <stdlib.h>		/* ldiv_t */
-
-ldiv_t
-ldiv(long num, long denom)
+lldiv_t
+lldiv(long long num, long long denom)
 {
-	ldiv_t r;
+	lldiv_t r;
 
 	/* see div.c for comments */
 
@@ -58,3 +48,5 @@
 	}
 	return (r);
 }
+
+__weak_alias(qdiv, lldiv);
diff --git a/libc/upstream-netbsd/lib/libc/string/memccpy.c b/libc/upstream-openbsd/lib/libc/string/memccpy.c
similarity index 83%
rename from libc/upstream-netbsd/lib/libc/string/memccpy.c
rename to libc/upstream-openbsd/lib/libc/string/memccpy.c
index c086241..635061b 100644
--- a/libc/upstream-netbsd/lib/libc/string/memccpy.c
+++ b/libc/upstream-openbsd/lib/libc/string/memccpy.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: memccpy.c,v 1.13 2012/06/25 22:32:46 abs Exp $	*/
+/*	$OpenBSD: memccpy.c,v 1.7 2015/08/31 02:53:57 guenther Exp $	*/
 
 /*-
  * Copyright (c) 1990, 1993
@@ -29,25 +29,12 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)memccpy.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: memccpy.c,v 1.13 2012/06/25 22:32:46 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
-#include <assert.h>
 #include <string.h>
 
 void *
 memccpy(void *t, const void *f, int c, size_t n)
 {
 
-	_DIAGASSERT(t != 0);
-	_DIAGASSERT(f != 0);
-
 	if (n) {
 		unsigned char *tp = t;
 		const unsigned char *fp = f;
@@ -59,3 +46,4 @@
 	}
 	return (0);
 }
+DEF_WEAK(memccpy);
diff --git a/libc/upstream-netbsd/lib/libc/string/strcasestr.c b/libc/upstream-openbsd/lib/libc/string/strcasestr.c
similarity index 83%
rename from libc/upstream-netbsd/lib/libc/string/strcasestr.c
rename to libc/upstream-openbsd/lib/libc/string/strcasestr.c
index f8a9444..abb3e15 100644
--- a/libc/upstream-netbsd/lib/libc/string/strcasestr.c
+++ b/libc/upstream-openbsd/lib/libc/string/strcasestr.c
@@ -1,4 +1,5 @@
-/*	$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $	*/
+/*	$OpenBSD: strcasestr.c,v 1.4 2015/08/31 02:53:57 guenther Exp $	*/
+/*	$NetBSD: strcasestr.c,v 1.2 2005/02/09 21:35:47 kleink Exp $	*/
 
 /*-
  * Copyright (c) 1990, 1993
@@ -32,13 +33,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: strcasestr.c,v 1.3 2005/11/29 03:12:00 christos Exp $");
-#endif /* LIBC_SCCS and not lint */
-
-#include "namespace.h"
-#include <assert.h>
 #include <ctype.h>
 #include <string.h>
 
@@ -51,11 +45,8 @@
 	char c, sc;
 	size_t len;
 
-	_DIAGASSERT(s != NULL);
-	_DIAGASSERT(find != NULL);
-
 	if ((c = *find++) != 0) {
-		c = tolower((unsigned char)c);
+		c = (char)tolower((unsigned char)c);
 		len = strlen(find);
 		do {
 			do {
@@ -65,5 +56,6 @@
 		} while (strncasecmp(s, find, len) != 0);
 		s--;
 	}
-	return __UNCONST(s);
+	return ((char *)s);
 }
+DEF_WEAK(strcasestr);
diff --git a/libc/upstream-netbsd/lib/libc/string/strcoll.c b/libc/upstream-openbsd/lib/libc/string/strcoll.c
similarity index 78%
rename from libc/upstream-netbsd/lib/libc/string/strcoll.c
rename to libc/upstream-openbsd/lib/libc/string/strcoll.c
index 77a0942..47a6ea4 100644
--- a/libc/upstream-netbsd/lib/libc/string/strcoll.c
+++ b/libc/upstream-openbsd/lib/libc/string/strcoll.c
@@ -1,8 +1,7 @@
-/*	$NetBSD: strcoll.c,v 1.10 2012/06/25 22:32:46 abs Exp $	*/
-
+/*	$OpenBSD: strcoll.c,v 1.6 2015/08/31 02:53:57 guenther Exp $ */
 /*-
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
@@ -32,16 +31,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)strcoll.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: strcoll.c,v 1.10 2012/06/25 22:32:46 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
-#include <assert.h>
 #include <string.h>
 
 /*
@@ -50,10 +39,7 @@
 int
 strcoll(const char *s1, const char *s2)
 {
-
-	_DIAGASSERT(s1 != NULL);
-	_DIAGASSERT(s2 != NULL);
-
 	/* LC_COLLATE is unimplemented, hence always "C" */
 	return (strcmp(s1, s2));
 }
+DEF_STRONG(strcoll);
diff --git a/libc/upstream-netbsd/lib/libc/string/strxfrm.c b/libc/upstream-openbsd/lib/libc/string/strxfrm.c
similarity index 73%
rename from libc/upstream-netbsd/lib/libc/string/strxfrm.c
rename to libc/upstream-openbsd/lib/libc/string/strxfrm.c
index 42c2a24..97df097 100644
--- a/libc/upstream-netbsd/lib/libc/string/strxfrm.c
+++ b/libc/upstream-openbsd/lib/libc/string/strxfrm.c
@@ -1,8 +1,7 @@
-/*	$NetBSD: strxfrm.c,v 1.12 2012/06/25 22:32:46 abs Exp $	*/
-
+/*	$OpenBSD: strxfrm.c,v 1.7 2015/08/31 02:53:57 guenther Exp $ */
 /*-
- * Copyright (c) 1990, 1993
- *	The Regents of the University of California.  All rights reserved.
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
  *
  * This code is derived from software contributed to Berkeley by
  * Chris Torek.
@@ -32,16 +31,6 @@
  * SUCH DAMAGE.
  */
 
-#include <sys/cdefs.h>
-#if defined(LIBC_SCCS) && !defined(lint)
-#if 0
-static char sccsid[] = "@(#)strxfrm.c	8.1 (Berkeley) 6/4/93";
-#else
-__RCSID("$NetBSD: strxfrm.c,v 1.12 2012/06/25 22:32:46 abs Exp $");
-#endif
-#endif /* LIBC_SCCS and not lint */
-
-#include <assert.h>
 #include <string.h>
 
 /*
@@ -52,19 +41,12 @@
 size_t
 strxfrm(char *dst, const char *src, size_t n)
 {
-	size_t srclen, copysize;
-
-	_DIAGASSERT(src != NULL);
 
 	/*
 	 * Since locales are unimplemented, this is just a copy.
 	 */
-	srclen = strlen(src);
-	if (n != 0) {
-		_DIAGASSERT(dst != NULL);
-		copysize = srclen < n ? srclen : n - 1;
-		(void)memcpy(dst, src, copysize);
-		dst[copysize] = 0;
-	}
-	return (srclen);
+	if (n == 0)
+		return (strlen(src));
+	return (strlcpy(dst, src, n));
 }
+DEF_STRONG(strxfrm);
diff --git a/libdl/Android.bp b/libdl/Android.bp
index 262da6c..c17e72e 100644
--- a/libdl/Android.bp
+++ b/libdl/Android.bp
@@ -105,6 +105,7 @@
         symbol_file: "libdl.map.txt",
         versions: ["10000"],
     },
+    required: ["libdl.mountpoint"],
 }
 
 ndk_library {
diff --git a/libm/Android.bp b/libm/Android.bp
index 28cf1fd..079220b 100644
--- a/libm/Android.bp
+++ b/libm/Android.bp
@@ -515,6 +515,7 @@
         symbol_file: "libm.map.txt",
         versions: ["10000"],
     },
+    required: ["libm.mountpoint"],
 }
 
 ndk_library {
diff --git a/libm/upstream-freebsd/lib/msun/ld128/e_powl.c b/libm/upstream-freebsd/lib/msun/ld128/e_powl.c
index 15a57dd..2f3ee55 100644
--- a/libm/upstream-freebsd/lib/msun/ld128/e_powl.c
+++ b/libm/upstream-freebsd/lib/msun/ld128/e_powl.c
@@ -32,7 +32,7 @@
  *	1. Compute and return log2(x) in two pieces:
  *		log2(x) = w1 + w2,
  *	   where w1 has 113-53 = 60 bit trailing zeros.
- *	2. Perform y*log2(x) = n+y' by simulating muti-precision
+ *	2. Perform y*log2(x) = n+y' by simulating multi-precision
  *	   arithmetic, where |y'|<=0.5.
  *	3. Return x**y = 2**n*exp(y'*log2)
  *
@@ -60,7 +60,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/ld128/e_powl.c 336362 2018-07-17 07:42:14Z bde $");
+__FBSDID("$FreeBSD: head/lib/msun/ld128/e_powl.c 342651 2018-12-31 15:43:06Z pfg $");
 
 #include <float.h>
 #include <math.h>
diff --git a/libm/upstream-freebsd/lib/msun/ld128/e_rem_pio2l.h b/libm/upstream-freebsd/lib/msun/ld128/e_rem_pio2l.h
index 5d78c4d..1ed79ae 100644
--- a/libm/upstream-freebsd/lib/msun/ld128/e_rem_pio2l.h
+++ b/libm/upstream-freebsd/lib/msun/ld128/e_rem_pio2l.h
@@ -14,7 +14,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
+__FBSDID("$FreeBSD: head/lib/msun/ld128/e_rem_pio2l.h 336545 2018-07-20 12:42:24Z bde $");
 
 /* ld128 version of __ieee754_rem_pio2l(x,y)
  * 
@@ -74,14 +74,9 @@
 	if (ex < BIAS + 45 || ex == BIAS + 45 &&
 	    u.bits.manh < 0x921fb54442d1LL) {
 	    /* |x| ~< 2^45*(pi/2), medium size */
-	    /* Use a specialized rint() to get fn.  Assume round-to-nearest. */
-	    fn = x*invpio2+0x1.8p112;
-	    fn = fn-0x1.8p112;
-#ifdef HAVE_EFFICIENT_I64RINT
+	    /* TODO: use only double precision for fn, as in expl(). */
+	    fn = rnintl(x * invpio2);
 	    n  = i64rint(fn);
-#else
-	    n  = fn;
-#endif
 	    r  = x-fn*pio2_1;
 	    w  = fn*pio2_1t;	/* 1st round good to 180 bit */
 	    {
diff --git a/libm/upstream-freebsd/lib/msun/ld128/k_expl.h b/libm/upstream-freebsd/lib/msun/ld128/k_expl.h
index 4c041e8..b80d00e 100644
--- a/libm/upstream-freebsd/lib/msun/ld128/k_expl.h
+++ b/libm/upstream-freebsd/lib/msun/ld128/k_expl.h
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/ld128/k_expl.h 326219 2017-11-26 02:00:33Z pfg $");
+__FBSDID("$FreeBSD: head/lib/msun/ld128/k_expl.h 336545 2018-07-20 12:42:24Z bde $");
 
 /*
  * ld128 version of k_expl.h.  See ../ld80/s_expl.c for most comments.
@@ -244,16 +244,8 @@
 	int n, n2;
 
 	/* Reduce x to (k*ln2 + endpoint[n2] + r1 + r2). */
-	/* Use a specialized rint() to get fn.  Assume round-to-nearest. */
-	/* XXX assume no extra precision for the additions, as for trig fns. */
-	/* XXX this set of comments is now quadruplicated. */
-	/* XXX but see ../src/e_exp.c for a fix using double_t. */
-	fn = (double)x * INV_L + 0x1.8p52 - 0x1.8p52;
-#if defined(HAVE_EFFICIENT_IRINT)
+	fn = rnint((double)x * INV_L);
 	n = irint(fn);
-#else
-	n = (int)fn;
-#endif
 	n2 = (unsigned)n % INTERVALS;
 	/* Depend on the sign bit being propagated: */
 	*kp = n >> LOG2_INTERVALS;
diff --git a/libm/upstream-freebsd/lib/msun/ld128/s_expl.c b/libm/upstream-freebsd/lib/msun/ld128/s_expl.c
index 53bc04a..f4c18be 100644
--- a/libm/upstream-freebsd/lib/msun/ld128/s_expl.c
+++ b/libm/upstream-freebsd/lib/msun/ld128/s_expl.c
@@ -29,7 +29,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/ld128/s_expl.c 326219 2017-11-26 02:00:33Z pfg $");
+__FBSDID("$FreeBSD: head/lib/msun/ld128/s_expl.c 336545 2018-07-20 12:42:24Z bde $");
 
 /*
  * ld128 version of s_expl.c.  See ../ld80/s_expl.c for most comments.
@@ -268,13 +268,8 @@
 	}
 
 	/* Reduce x to (k*ln2 + endpoint[n2] + r1 + r2). */
-	/* Use a specialized rint() to get fn.  Assume round-to-nearest. */
-	fn = (double)x * INV_L + 0x1.8p52 - 0x1.8p52;
-#if defined(HAVE_EFFICIENT_IRINT)
+	fn = rnint((double)x * INV_L);
 	n = irint(fn);
-#else
-	n = (int)fn;
-#endif
 	n2 = (unsigned)n % INTERVALS;
 	k = n >> LOG2_INTERVALS;
 	r1 = x - fn * L1;
diff --git a/libm/upstream-freebsd/lib/msun/src/e_j0.c b/libm/upstream-freebsd/lib/msun/src/e_j0.c
index cfa71c2..6bca542 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_j0.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_j0.c
@@ -11,7 +11,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/e_j0.c 336089 2018-07-08 16:26:13Z markj $");
+__FBSDID("$FreeBSD: head/lib/msun/src/e_j0.c 343023 2019-01-14 15:48:35Z pfg $");
 
 /* __ieee754_j0(x), __ieee754_y0(x)
  * Bessel function of the first and second kinds of order zero.
@@ -80,7 +80,7 @@
 S03  =  5.13546550207318111446e-07, /* 0x3EA13B54, 0xCE84D5A9 */
 S04  =  1.16614003333790000205e-09; /* 0x3E1408BC, 0xF4745D8F */
 
-static const double zero = 0.0;
+static const double zero = 0, qrtr = 0.25;
 
 double
 __ieee754_j0(double x)
@@ -97,7 +97,7 @@
 		c = cos(x);
 		ss = s-c;
 		cc = s+c;
-		if(ix<0x7fe00000) {  /* make sure x+x not overflow */
+		if(ix<0x7fe00000) {  /* Make sure x+x does not overflow. */
 		    z = -cos(x+x);
 		    if ((s*c)<zero) cc = z/ss;
 		    else 	    ss = z/cc;
@@ -123,9 +123,9 @@
 	r =  z*(R02+z*(R03+z*(R04+z*R05)));
 	s =  one+z*(S01+z*(S02+z*(S03+z*S04)));
 	if(ix < 0x3FF00000) {	/* |x| < 1.00 */
-	    return one + z*(-0.25+(r/s));
+	    return one + z*((r/s)-qrtr);
 	} else {
-	    u = 0.5*x;
+	    u = x/2;
 	    return((one+u)*(one-u)+z*(r/s));
 	}
 }
@@ -374,6 +374,7 @@
 static __inline double
 qzero(double x)
 {
+	static const double eighth = 0.125;
 	const double *p,*q;
 	double s,r,z;
 	int32_t ix;
@@ -386,5 +387,5 @@
 	z = one/(x*x);
 	r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 	s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5])))));
-	return (-.125 + r/s)/x;
+	return (r/s-eighth)/x;
 }
diff --git a/libm/upstream-freebsd/lib/msun/src/e_j0f.c b/libm/upstream-freebsd/lib/msun/src/e_j0f.c
index e53b218..714caac 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_j0f.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_j0f.c
@@ -14,7 +14,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/e_j0f.c 283032 2015-05-17 16:27:06Z kargl $");
+__FBSDID("$FreeBSD: head/lib/msun/src/e_j0f.c 343023 2019-01-14 15:48:35Z pfg $");
 
 /*
  * See e_j0.c for complete comments.
@@ -42,7 +42,7 @@
 S03  =  5.1354652442e-07, /* 0x3509daa6 */
 S04  =  1.1661400734e-09; /* 0x30a045e8 */
 
-static const float zero = 0.0;
+static const float zero = 0, qrtr = 0.25;
 
 float
 __ieee754_j0f(float x)
@@ -59,7 +59,7 @@
 		c = cosf(x);
 		ss = s-c;
 		cc = s+c;
-		if(ix<0x7f000000) {  /* make sure x+x not overflow */
+		if(ix<0x7f000000) {  /* Make sure x+x does not overflow. */
 		    z = -cosf(x+x);
 		    if ((s*c)<zero) cc = z/ss;
 		    else 	    ss = z/cc;
@@ -85,9 +85,9 @@
 	r =  z*(R02+z*(R03+z*(R04+z*R05)));
 	s =  one+z*(S01+z*(S02+z*(S03+z*S04)));
 	if(ix < 0x3F800000) {	/* |x| < 1.00 */
-	    return one + z*((float)-0.25+(r/s));
+	    return one + z*((r/s)-qrtr);
 	} else {
-	    u = (float)0.5*x;
+	    u = x/2;
 	    return((one+u)*(one-u)+z*(r/s));
 	}
 }
@@ -328,6 +328,7 @@
 static __inline float
 qzerof(float x)
 {
+	static const float eighth = 0.125;
 	const float *p,*q;
 	float s,r,z;
 	int32_t ix;
@@ -340,5 +341,5 @@
 	z = one/(x*x);
 	r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 	s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5])))));
-	return (-(float).125 + r/s)/x;
+	return (r/s-eighth)/x;
 }
diff --git a/libm/upstream-freebsd/lib/msun/src/e_pow.c b/libm/upstream-freebsd/lib/msun/src/e_pow.c
index 411dd52..b4f6a5a 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_pow.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_pow.c
@@ -10,7 +10,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/e_pow.c 336362 2018-07-17 07:42:14Z bde $");
+__FBSDID("$FreeBSD: head/lib/msun/src/e_pow.c 342851 2019-01-07 17:35:09Z pfg $");
 
 /* __ieee754_pow(x,y) return x**y
  *
@@ -133,7 +133,7 @@
 		k = (iy>>20)-0x3ff;	   /* exponent */
 		if(k>20) {
 		    j = ly>>(52-k);
-		    if((j<<(52-k))==ly) yisint = 2-(j&1);
+		    if(((u_int32_t)j<<(52-k))==ly) yisint = 2-(j&1);
 		} else if(ly==0) {
 		    j = iy>>(20-k);
 		    if((j<<(20-k))==iy) yisint = 2-(j&1);
diff --git a/libm/upstream-freebsd/lib/msun/src/e_rem_pio2.c b/libm/upstream-freebsd/lib/msun/src/e_rem_pio2.c
index be2630b..3e62c2b 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_rem_pio2.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_rem_pio2.c
@@ -14,7 +14,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
+__FBSDID("$FreeBSD: head/lib/msun/src/e_rem_pio2.c 336545 2018-07-20 12:42:24Z bde $");
 
 /* __ieee754_rem_pio2(x,y)
  * 
@@ -127,14 +127,8 @@
 	}
 	if(ix<0x413921fb) {	/* |x| ~< 2^20*(pi/2), medium size */
 medium:
-	    /* Use a specialized rint() to get fn.  Assume round-to-nearest. */
-	    STRICT_ASSIGN(double,fn,x*invpio2+0x1.8p52);
-	    fn = fn-0x1.8p52;
-#ifdef HAVE_EFFICIENT_IRINT
+	    fn = rnint((double_t)x*invpio2);
 	    n  = irint(fn);
-#else
-	    n  = (int32_t)fn;
-#endif
 	    r  = x-fn*pio2_1;
 	    w  = fn*pio2_1t;	/* 1st round good to 85 bit */
 	    {
diff --git a/libm/upstream-freebsd/lib/msun/src/e_rem_pio2f.c b/libm/upstream-freebsd/lib/msun/src/e_rem_pio2f.c
index f1ee7a0..2a89d27 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_rem_pio2f.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_rem_pio2f.c
@@ -15,7 +15,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
+__FBSDID("$FreeBSD: head/lib/msun/src/e_rem_pio2f.c 336545 2018-07-20 12:42:24Z bde $");
 
 /* __ieee754_rem_pio2f(x,y)
  *
@@ -55,14 +55,8 @@
 	ix = hx&0x7fffffff;
     /* 33+53 bit pi is good enough for medium size */
 	if(ix<0x4dc90fdb) {		/* |x| ~< 2^28*(pi/2), medium size */
-	    /* Use a specialized rint() to get fn.  Assume round-to-nearest. */
-	    STRICT_ASSIGN(double,fn,x*invpio2+0x1.8p52);
-	    fn = fn-0x1.8p52;
-#ifdef HAVE_EFFICIENT_IRINT
+	    fn = rnint((float_t)x*invpio2);
 	    n  = irint(fn);
-#else
-	    n  = (int32_t)fn;
-#endif
 	    r  = x-fn*pio2_1;
 	    w  = fn*pio2_1t;
 	    *y = r-w;
diff --git a/libm/upstream-freebsd/lib/msun/src/k_rem_pio2.c b/libm/upstream-freebsd/lib/msun/src/k_rem_pio2.c
index 81363d4..0869e03 100644
--- a/libm/upstream-freebsd/lib/msun/src/k_rem_pio2.c
+++ b/libm/upstream-freebsd/lib/msun/src/k_rem_pio2.c
@@ -12,7 +12,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/k_rem_pio2.c 298896 2016-05-01 19:37:33Z pfg $");
+__FBSDID("$FreeBSD: head/lib/msun/src/k_rem_pio2.c 342651 2018-12-31 15:43:06Z pfg $");
 
 /*
  * __kernel_rem_pio2(x,y,e0,nx,prec)
@@ -52,7 +52,7 @@
  *			64-bit  precision	2
  *			113-bit precision	3
  *		The actual value is the sum of them. Thus for 113-bit
- *		precison, one may have to do something like:
+ *		precision, one may have to do something like:
  *
  *		long double t,w,r_head, r_tail;
  *		t = (long double)y[2] + (long double)y[1];
diff --git a/libm/upstream-freebsd/lib/msun/src/s_cbrt.c b/libm/upstream-freebsd/lib/msun/src/s_cbrt.c
index d75ad0b..268425e 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_cbrt.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_cbrt.c
@@ -13,8 +13,9 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/s_cbrt.c 298896 2016-05-01 19:37:33Z pfg $");
+__FBSDID("$FreeBSD: head/lib/msun/src/s_cbrt.c 342563 2018-12-28 01:34:08Z jhibbits $");
 
+#include <float.h>
 #include "math.h"
 #include "math_private.h"
 
diff --git a/libm/upstream-freebsd/lib/msun/src/s_cpow.c b/libm/upstream-freebsd/lib/msun/src/s_cpow.c
index 9be5c51..1cb99aa 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_cpow.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_cpow.c
@@ -44,11 +44,12 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/s_cpow.c 336299 2018-07-15 00:23:10Z mmacy $");
+__FBSDID("$FreeBSD: head/lib/msun/src/s_cpow.c 336563 2018-07-20 18:27:30Z dim $");
 
 #include <complex.h>
 #include <float.h>
 #include <math.h>
+#include "math_private.h"
 
 double complex
 cpow(double complex a, double complex z)
@@ -60,7 +61,7 @@
 	y = cimag (z);
 	absa = cabs (a);
 	if (absa == 0.0) {
-		return (0.0 + 0.0 * I);
+		return (CMPLX(0.0, 0.0));
 	}
 	arga = carg (a);
 	r = pow (absa, x);
@@ -69,6 +70,6 @@
 		r = r * exp (-y * arga);
 		theta = theta + y * log (absa);
 	}
-	w = r * cos (theta) + (r * sin (theta)) * I;
+	w = CMPLX(r * cos (theta),  r * sin (theta));
 	return (w);
 }
diff --git a/libm/upstream-freebsd/lib/msun/src/s_cpowf.c b/libm/upstream-freebsd/lib/msun/src/s_cpowf.c
index 6e27f57..a2ef525 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_cpowf.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_cpowf.c
@@ -44,10 +44,11 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/s_cpowf.c 336299 2018-07-15 00:23:10Z mmacy $");
+__FBSDID("$FreeBSD: head/lib/msun/src/s_cpowf.c 336563 2018-07-20 18:27:30Z dim $");
 
 #include <complex.h>
 #include <math.h>
+#include "math_private.h"
 
 float complex
 cpowf(float complex a, float complex z)
@@ -59,7 +60,7 @@
 	y = cimagf(z);
 	absa = cabsf (a);
 	if (absa == 0.0f) {
-		return (0.0f + 0.0f * I);
+		return (CMPLXF(0.0f, 0.0f));
 	}
 	arga = cargf (a);
 	r = powf (absa, x);
@@ -68,6 +69,6 @@
 		r = r * expf (-y * arga);
 		theta = theta + y * logf (absa);
 	}
-	w = r * cosf (theta) + (r * sinf (theta)) * I;
+	w = CMPLXF(r * cosf (theta), r * sinf (theta));
 	return (w);
 }
diff --git a/libm/upstream-freebsd/lib/msun/src/s_cpowl.c b/libm/upstream-freebsd/lib/msun/src/s_cpowl.c
index fcb5c7f..f9c6373 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_cpowl.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_cpowl.c
@@ -44,10 +44,11 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/s_cpowl.c 336299 2018-07-15 00:23:10Z mmacy $");
+__FBSDID("$FreeBSD: head/lib/msun/src/s_cpowl.c 336563 2018-07-20 18:27:30Z dim $");
 
 #include <complex.h>
 #include <math.h>
+#include "math_private.h"
 
 long double complex
 cpowl(long double complex a, long double complex z)
@@ -59,7 +60,7 @@
 	y = cimagl(z);
 	absa = cabsl(a);
 	if (absa == 0.0L) {
-		return (0.0L + 0.0L * I);
+		return (CMPLXL(0.0L, 0.0L));
 	}
 	arga = cargl(a);
 	r = powl(absa, x);
@@ -68,6 +69,6 @@
 		r = r * expl(-y * arga);
 		theta = theta + y * logl(absa);
 	}
-	w = r * cosl(theta) + (r * sinl(theta)) * I;
+	w = CMPLXL(r * cosl(theta), r * sinl(theta));
 	return (w);
 }
diff --git a/libm/upstream-freebsd/lib/msun/src/s_cproj.c b/libm/upstream-freebsd/lib/msun/src/s_cproj.c
index 3083f2b..7677b5f 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_cproj.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_cproj.c
@@ -27,9 +27,10 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/s_cproj.c 326219 2017-11-26 02:00:33Z pfg $");
+__FBSDID("$FreeBSD: head/lib/msun/src/s_cproj.c 342563 2018-12-28 01:34:08Z jhibbits $");
 
 #include <complex.h>
+#include <float.h>
 #include <math.h>
 
 #include "math_private.h"
diff --git a/libm/upstream-freebsd/lib/msun/src/s_erf.c b/libm/upstream-freebsd/lib/msun/src/s_erf.c
index e1d63bc..3e39d80 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_erf.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_erf.c
@@ -11,7 +11,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
+__FBSDID("$FreeBSD: head/lib/msun/src/s_erf.c 342563 2018-12-28 01:34:08Z jhibbits $");
 
 /* double erf(double x)
  * double erfc(double x)
@@ -107,7 +107,7 @@
  *	   	erfc/erf(NaN) is NaN
  */
 
-
+#include <float.h>
 #include "math.h"
 #include "math_private.h"
 
diff --git a/linker/Android.bp b/linker/Android.bp
index 5ae09ba..fed921d 100644
--- a/linker/Android.bp
+++ b/linker/Android.bp
@@ -103,6 +103,7 @@
     name: "linker_sources_arm64",
     srcs: [
         "arch/arm64/begin.S",
+        "arch/arm64/tlsdesc_resolver.S",
     ],
 }
 
@@ -282,6 +283,8 @@
 
     name: "linker",
     symlinks: ["linker_asan"],
+    // The linker in the system partition is now only for bootstrapping
+    relative_install_path: "bootstrap",
     recovery_available: true,
     multilib: {
         lib32: {
@@ -300,6 +303,7 @@
     },
     compile_multilib: "both",
     xom: false,
+    required: ["linker.mountpoint"],
 }
 
 cc_library {
diff --git a/linker/arch/arm64/tlsdesc_resolver.S b/linker/arch/arm64/tlsdesc_resolver.S
new file mode 100644
index 0000000..ef46839
--- /dev/null
+++ b/linker/arch/arm64/tlsdesc_resolver.S
@@ -0,0 +1,203 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <private/bionic_asm.h>
+#include <private/bionic_asm_tls.h>
+
+.globl __tls_get_addr
+
+// These resolver functions must preserve every register except x0. They set x0
+// to the offset of the TLS symbol relative to the thread pointer.
+
+ENTRY_PRIVATE(tlsdesc_resolver_static)
+  ldr x0, [x0, #8]
+  ret
+END(tlsdesc_resolver_static)
+
+ENTRY_PRIVATE(tlsdesc_resolver_dynamic)
+  stp x19, x20, [sp, #-32]!
+  .cfi_def_cfa_offset 32
+  .cfi_rel_offset x19, 0
+  .cfi_rel_offset x20, 8
+  stp x21, x22, [sp, #16]
+  .cfi_rel_offset x21, 16
+  .cfi_rel_offset x22, 24
+
+  mrs x19, tpidr_el0            // __get_tls()
+  ldr x20, [x19, #(TLS_SLOT_DTV * 8)]
+  ldr x21, [x20]                // TlsDtv::generation
+
+  ldr x0, [x0, #8]              // TlsDynamicResolverArg*
+  ldr x22, [x0]                 // TlsDynamicResolverArg::generation
+
+  cmp x21, x22
+  b.lo .fallback
+
+  ldr x21, [x0, #8]             // TlsIndex::module
+  ldr x22, [x0, #16]            // TlsIndex::offset
+  ldr x21, [x20, x21, lsl #3]   // TlsDtv::modules[module]
+  cbz x21, .fallback
+  add x0, x21, x22
+  sub x0, x0, x19
+
+  ldp x21, x22, [sp, #16]
+  .cfi_remember_state
+  .cfi_restore x21
+  .cfi_restore x22
+  ldp x19, x20, [sp], #32
+  .cfi_adjust_cfa_offset -32
+  .cfi_restore x19
+  .cfi_restore x20
+  ret
+
+.fallback:
+  .cfi_restore_state
+  ldp x21, x22, [sp, #16]
+  .cfi_restore x21
+  .cfi_restore x22
+  ldp x19, x20, [sp], #32
+  .cfi_adjust_cfa_offset -32
+  .cfi_restore x19
+  .cfi_restore x20
+  b tlsdesc_resolver_dynamic_slow_path
+END(tlsdesc_resolver_dynamic)
+
+#define SAVE_REG(x, slot)                 \
+    str x, [sp, #((slot) * 8)];           \
+    .cfi_rel_offset x, (slot) * 8;        \
+
+#define SAVE_GPR_PAIR(x, y, slot)         \
+    stp x, y, [sp, #((slot) * 8)];        \
+    .cfi_rel_offset x, (slot) * 8;        \
+    .cfi_rel_offset y, ((slot) + 1) * 8;  \
+
+#define SAVE_VEC_PAIR(x, y, slot)         \
+    stp x, y, [sp, #((slot) * 8)];        \
+    .cfi_rel_offset x, (slot) * 8;        \
+    .cfi_rel_offset y, ((slot) + 2) * 8;  \
+
+#define RESTORE_REG(x, slot)              \
+    ldr x, [sp, #((slot) * 8)];           \
+    .cfi_restore x;                       \
+
+#define RESTORE_REG_PAIR(x, y, slot)      \
+    ldp x, y, [sp, #((slot) * 8)];        \
+    .cfi_restore x;                       \
+    .cfi_restore y;                       \
+
+// On entry, x0 is the address of a TlsDynamicResolverArg object rather than
+// the TlsDescriptor address passed to the original resolver function.
+ENTRY_PRIVATE(tlsdesc_resolver_dynamic_slow_path)
+  sub sp, sp, #(8 * 84)
+  .cfi_def_cfa_offset (8 * 84)
+  SAVE_GPR_PAIR(x29, x30, 0)
+  mov x29, sp
+
+  // Avoid leaking the contents of the shadow call stack register (x18) into
+  // memory. x19 through x29 are callee-save registers, so we do not need to
+  // save them.
+  SAVE_GPR_PAIR(x1,  x2,  2)
+  SAVE_GPR_PAIR(x3,  x4,  4)
+  SAVE_GPR_PAIR(x5,  x6,  6)
+  SAVE_GPR_PAIR(x7,  x8,  8)
+  SAVE_GPR_PAIR(x9,  x10, 10)
+  SAVE_GPR_PAIR(x11, x12, 12)
+  SAVE_GPR_PAIR(x13, x14, 14)
+  SAVE_GPR_PAIR(x15, x16, 16)
+  SAVE_REG(x17, 18)
+
+  SAVE_VEC_PAIR(q0,  q1,  20)
+  SAVE_VEC_PAIR(q2,  q3,  24)
+  SAVE_VEC_PAIR(q4,  q5,  28)
+  SAVE_VEC_PAIR(q6,  q7,  32)
+  SAVE_VEC_PAIR(q8,  q9,  36)
+  SAVE_VEC_PAIR(q10, q11, 40)
+  SAVE_VEC_PAIR(q12, q13, 44)
+  SAVE_VEC_PAIR(q14, q15, 48)
+  SAVE_VEC_PAIR(q16, q17, 52)
+  SAVE_VEC_PAIR(q18, q19, 56)
+  SAVE_VEC_PAIR(q20, q21, 60)
+  SAVE_VEC_PAIR(q22, q23, 64)
+  SAVE_VEC_PAIR(q24, q25, 68)
+  SAVE_VEC_PAIR(q26, q27, 72)
+  SAVE_VEC_PAIR(q28, q29, 76)
+  SAVE_VEC_PAIR(q30, q31, 80)
+
+  add x0, x0, #8
+  bl __tls_get_addr
+  mrs x1, tpidr_el0 // __get_tls()
+  sub x0, x0, x1
+
+  RESTORE_REG_PAIR(q30, q31, 80)
+  RESTORE_REG_PAIR(q28, q29, 76)
+  RESTORE_REG_PAIR(q26, q27, 72)
+  RESTORE_REG_PAIR(q24, q25, 68)
+  RESTORE_REG_PAIR(q22, q23, 64)
+  RESTORE_REG_PAIR(q20, q21, 60)
+  RESTORE_REG_PAIR(q18, q19, 56)
+  RESTORE_REG_PAIR(q16, q17, 52)
+  RESTORE_REG_PAIR(q14, q15, 48)
+  RESTORE_REG_PAIR(q12, q13, 44)
+  RESTORE_REG_PAIR(q10, q11, 40)
+  RESTORE_REG_PAIR(q8,  q9,  36)
+  RESTORE_REG_PAIR(q6,  q7,  32)
+  RESTORE_REG_PAIR(q4,  q5,  28)
+  RESTORE_REG_PAIR(q2,  q3,  24)
+  RESTORE_REG_PAIR(q0,  q1,  20)
+
+  RESTORE_REG(x17, 18)
+  RESTORE_REG_PAIR(x15, x16, 16)
+  RESTORE_REG_PAIR(x13, x14, 14)
+  RESTORE_REG_PAIR(x11, x12, 12)
+  RESTORE_REG_PAIR(x9,  x10, 10)
+  RESTORE_REG_PAIR(x7,  x8,  8)
+  RESTORE_REG_PAIR(x5,  x6,  6)
+  RESTORE_REG_PAIR(x3,  x4,  4)
+  RESTORE_REG_PAIR(x1,  x2,  2)
+
+  RESTORE_REG_PAIR(x29, x30, 0)
+  add sp, sp, #(8 * 84)
+  .cfi_def_cfa_offset 0
+  ret
+END(tlsdesc_resolver_dynamic_slow_path)
+
+// The address of an unresolved weak TLS symbol evaluates to NULL with TLSDESC.
+// The value returned by this function is added to the thread pointer, so return
+// a negated thread pointer to cancel it out.
+ENTRY_PRIVATE(tlsdesc_resolver_unresolved_weak)
+  str x19, [sp, #-16]!
+  .cfi_def_cfa_offset 16
+  .cfi_rel_offset x19, 0
+  ldr x19, [x0, #8]
+  mrs x0, tpidr_el0             // __get_tls()
+  sub x0, x19, x0
+  ldr x19, [sp], #16
+  .cfi_def_cfa_offset 0
+  .cfi_restore x19
+  ret
+END(tlsdesc_resolver_unresolved_weak)
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 4dcdf7e..428dd25 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -536,6 +536,10 @@
     allocator_.free(ptr);
   }
 
+  static void purge() {
+    allocator_.purge();
+  }
+
  private:
   static LinkerBlockAllocator allocator_;
 };
@@ -553,6 +557,10 @@
   static void free(T* ptr) {
     SizeBasedAllocator<sizeof(T)>::free(ptr);
   }
+
+  static void purge() {
+    SizeBasedAllocator<sizeof(T)>::purge();
+  }
 };
 
 class LoadTask {
@@ -2074,6 +2082,8 @@
          ns == nullptr ? "(null)" : ns->get_name(),
          ns);
 
+  auto purge_guard = android::base::make_scope_guard([&]() { purge_unused_memory(); });
+
   auto failure_guard = android::base::make_scope_guard(
       [&]() { LD_LOG(kLogDlopen, "... dlopen failed: %s", linker_get_error_buffer()); });
 
@@ -2698,6 +2708,7 @@
 bool soinfo::relocate(const VersionTracker& version_tracker, ElfRelIteratorT&& rel_iterator,
                       const soinfo_list_t& global_group, const soinfo_list_t& local_group) {
   const size_t tls_tp_base = __libc_shared_globals()->static_tls_layout.offset_thread_pointer();
+  std::vector<std::pair<TlsDescriptor*, size_t>> deferred_tlsdesc_relocs;
 
   for (size_t idx = 0; rel_iterator.has_next(); ++idx) {
     const auto rel = rel_iterator.next();
@@ -2977,6 +2988,49 @@
 #endif  // !defined(__aarch64__)
 
 #if defined(__aarch64__)
+      // Bionic currently only implements TLSDESC for arm64. This implementation should work with
+      // other architectures, as long as the resolver functions are implemented.
+      case R_GENERIC_TLSDESC:
+        count_relocation(kRelocRelative);
+        MARK(rel->r_offset);
+        {
+          TlsDescriptor* desc = reinterpret_cast<TlsDescriptor*>(reloc);
+          if (lsi == nullptr) {
+            // Unresolved weak relocation.
+            desc->func = tlsdesc_resolver_unresolved_weak;
+            desc->arg = addend;
+            TRACE_TYPE(RELO, "RELO TLSDESC %16p <- unresolved weak 0x%zx %s\n",
+                       reinterpret_cast<void*>(reloc), static_cast<size_t>(addend), sym_name);
+          } else {
+            CHECK(lsi->get_tls() != nullptr); // We rejected a missing TLS segment above.
+            size_t module_id = lsi->get_tls()->module_id;
+            const TlsModule& mod = get_tls_module(module_id);
+            if (mod.static_offset != SIZE_MAX) {
+              desc->func = tlsdesc_resolver_static;
+              desc->arg = mod.static_offset - tls_tp_base + sym_addr + addend;
+              TRACE_TYPE(RELO, "RELO TLSDESC %16p <- static (0x%zx - 0x%zx + 0x%zx + 0x%zx) %s\n",
+                         reinterpret_cast<void*>(reloc), mod.static_offset, tls_tp_base,
+                         static_cast<size_t>(sym_addr), static_cast<size_t>(addend), sym_name);
+            } else {
+              tlsdesc_args_.push_back({
+                .generation = mod.first_generation,
+                .index.module_id = module_id,
+                .index.offset = sym_addr + addend,
+              });
+              // Defer the TLSDESC relocation until the address of the TlsDynamicResolverArg object
+              // is finalized.
+              deferred_tlsdesc_relocs.push_back({ desc, tlsdesc_args_.size() - 1 });
+              const TlsDynamicResolverArg& desc_arg = tlsdesc_args_.back();
+              TRACE_TYPE(RELO, "RELO TLSDESC %16p <- dynamic (gen %zu, mod %zu, off %zu) %s",
+                         reinterpret_cast<void*>(reloc), desc_arg.generation,
+                         desc_arg.index.module_id, desc_arg.index.offset, sym_name);
+            }
+          }
+        }
+        break;
+#endif  // defined(R_GENERIC_TLSDESC)
+
+#if defined(__aarch64__)
       case R_AARCH64_ABS64:
         count_relocation(kRelocAbsolute);
         MARK(rel->r_offset);
@@ -3145,6 +3199,13 @@
         return false;
     }
   }
+
+  for (const std::pair<TlsDescriptor*, size_t>& pair : deferred_tlsdesc_relocs) {
+    TlsDescriptor* desc = pair.first;
+    desc->func = tlsdesc_resolver_dynamic;
+    desc->arg = reinterpret_cast<size_t>(&tlsdesc_args_[pair.second]);
+  }
+
   return true;
 }
 #endif  // !defined(__mips__)
@@ -4018,3 +4079,17 @@
   }
   return it->second;
 }
+
+void purge_unused_memory() {
+  // For now, we only purge the memory used by LoadTask because we know those
+  // are temporary objects.
+  //
+  // Purging other LinkerBlockAllocator hardly yields much because they hold
+  // information about namespaces and opened libraries, which are not freed
+  // when the control leaves the linker.
+  //
+  // Purging BionicAllocator may give us a few dirty pages back, but those pages
+  // would be already zeroed out, so they compress easily in ZRAM.  Therefore,
+  // it is not worth munmap()'ing those pages.
+  TypeBasedAllocator<LoadTask>::purge();
+}
diff --git a/linker/linker.h b/linker/linker.h
index 91d3ddf..964c266 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -186,3 +186,5 @@
 
 void increment_dso_handle_reference_counter(void* dso_handle);
 void decrement_dso_handle_reference_counter(void* dso_handle);
+
+void purge_unused_memory();
diff --git a/linker/linker_block_allocator.cpp b/linker/linker_block_allocator.cpp
index 27f1e38..fdb4c85 100644
--- a/linker/linker_block_allocator.cpp
+++ b/linker/linker_block_allocator.cpp
@@ -109,9 +109,6 @@
   free_block_list_ = block_info;
 
   --allocated_;
-  if (allocated_ == 0) {
-    free_all_pages();
-  }
 }
 
 void LinkerBlockAllocator::protect_all(int prot) {
@@ -163,9 +160,9 @@
   abort();
 }
 
-void LinkerBlockAllocator::free_all_pages() {
+void LinkerBlockAllocator::purge() {
   if (allocated_) {
-    abort();
+    return;
   }
 
   LinkerBlockAllocatorPage* page = page_list_;
diff --git a/linker/linker_block_allocator.h b/linker/linker_block_allocator.h
index 458d092..8ae4094 100644
--- a/linker/linker_block_allocator.h
+++ b/linker/linker_block_allocator.h
@@ -50,10 +50,12 @@
   void free(void* block);
   void protect_all(int prot);
 
+  // Purge all pages if all previously allocated blocks have been freed.
+  void purge();
+
  private:
   void create_new_page();
   LinkerBlockAllocatorPage* find_page(void* block);
-  void free_all_pages();
 
   size_t block_size_;
   LinkerBlockAllocatorPage* page_list_;
@@ -75,8 +77,7 @@
  *    513 this allocator will use 516 (520 for lp64) bytes of data where
  *    generalized implementation is going to use 1024 sized blocks.
  *
- * 2. Unless all allocated memory is freed, this allocator does not munmap
- *    allocated memory, where BionicAllocator does.
+ * 2. This allocator does not munmap allocated memory, where BionicAllocator does.
  *
  * 3. This allocator provides mprotect services to the user, where BionicAllocator
  *    always treats its memory as READ|WRITE.
diff --git a/linker/linker_main.cpp b/linker/linker_main.cpp
index b0c27dc..7486cd7 100644
--- a/linker/linker_main.cpp
+++ b/linker/linker_main.cpp
@@ -503,6 +503,10 @@
   fflush(stdout);
 #endif
 
+  // We are about to hand control over to the executable loaded.  We don't want
+  // to leave dirty pages behind unnecessarily.
+  purge_unused_memory();
+
   ElfW(Addr) entry = exe_info.entry_point;
   TRACE("[ Ready to execute \"%s\" @ %p ]", si->get_realpath(), reinterpret_cast<void*>(entry));
   return entry;
diff --git a/linker/linker_soinfo.h b/linker/linker_soinfo.h
index 3499cf7..dd9c6aa 100644
--- a/linker/linker_soinfo.h
+++ b/linker/linker_soinfo.h
@@ -32,6 +32,7 @@
 
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "private/bionic_elf_tls.h"
 #include "linker_namespaces.h"
@@ -379,6 +380,7 @@
 
   // version >= 5
   std::unique_ptr<soinfo_tls> tls_;
+  std::vector<TlsDynamicResolverArg> tlsdesc_args_;
 };
 
 // This function is used by dlvsym() to calculate hash of sym_ver
diff --git a/linker/linker_tls.h b/linker/linker_tls.h
index fbb1dcf..87e1f0d 100644
--- a/linker/linker_tls.h
+++ b/linker/linker_tls.h
@@ -30,6 +30,8 @@
 
 #include <stdlib.h>
 
+#include "private/bionic_elf_tls.h"
+
 struct TlsModule;
 struct soinfo;
 
@@ -40,3 +42,24 @@
 void unregister_soinfo_tls(soinfo* si);
 
 const TlsModule& get_tls_module(size_t module_id);
+
+typedef size_t TlsDescResolverFunc(size_t);
+
+struct TlsDescriptor {
+#if defined(__arm__)
+  size_t arg;
+  TlsDescResolverFunc* func;
+#else
+  TlsDescResolverFunc* func;
+  size_t arg;
+#endif
+};
+
+struct TlsDynamicResolverArg {
+  size_t generation;
+  TlsIndex index;
+};
+
+__LIBC_HIDDEN__ extern "C" size_t tlsdesc_resolver_static(size_t);
+__LIBC_HIDDEN__ extern "C" size_t tlsdesc_resolver_dynamic(size_t);
+__LIBC_HIDDEN__ extern "C" size_t tlsdesc_resolver_unresolved_weak(size_t);
diff --git a/tests/Android.bp b/tests/Android.bp
index 8b921d8..c1d19fa 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -95,6 +95,7 @@
         "grp_pwd_file_test.cpp",
         "iconv_test.cpp",
         "ifaddrs_test.cpp",
+        "ifunc_test.cpp",
         "inttypes_test.cpp",
         "iso646_test.c",
         "langinfo_test.cpp",
@@ -520,6 +521,7 @@
         "libtest_dt_runpath_b",
         "libtest_dt_runpath_c",
         "libtest_dt_runpath_x",
+        "libtest_dt_runpath_y",
         "libatest_simple_zip",
         "libcfi-test",
         "libcfi-test-bad",
@@ -533,7 +535,6 @@
         "libdl_preempt_test_1",
         "libdl_preempt_test_2",
         "libdl_test_df_1_global",
-        "libelf-tls-library",
         "libgnu-hash-table-library",
         "libsysv-hash-table-library",
         "libtestshared",
@@ -571,6 +572,10 @@
         "libtest_dlsym_from_this",
         "libtest_dlsym_weak_func",
         "libtest_dt_runpath_d",
+        "libtest_elftls_dynamic",
+        "libtest_elftls_dynamic_filler_1",
+        "libtest_elftls_dynamic_filler_2",
+        "libtest_elftls_dynamic_filler_3",
         "libtest_elftls_shared_var",
         "libtest_elftls_shared_var_ie",
         "libtest_elftls_tprel",
diff --git a/tests/Android.build.mk b/tests/Android.build.mk
index 266c7d7..04fc92d 100644
--- a/tests/Android.build.mk
+++ b/tests/Android.build.mk
@@ -35,8 +35,20 @@
     native_tests_var := TARGET_OUT_DATA_NATIVE_TESTS
   endif
 
-  LOCAL_MODULE_PATH_32 := $($(TARGET_2ND_ARCH_VAR_PREFIX)$(native_tests_var))/$($(module)_install_to_native_tests_dir)
-  LOCAL_MODULE_PATH_64 := $($(native_tests_var))/$($(module)_install_to_native_tests_dir)
+  ifneq ($($(module)_install_to_native_tests_dir_32),)
+    tests_dir_32 := $($(module)_install_to_native_tests_dir_32)
+  else
+    tests_dir_32 := $($(module)_install_to_native_tests_dir)
+  endif
+
+  ifneq ($($(module)_install_to_native_tests_dir_64),)
+    tests_dir_64 := $($(module)_install_to_native_tests_dir_64)
+  else
+    tests_dir_64 := $($(module)_install_to_native_tests_dir)
+  endif
+
+  LOCAL_MODULE_PATH_32 := $($(TARGET_2ND_ARCH_VAR_PREFIX)$(native_tests_var))/$(tests_dir_32)
+  LOCAL_MODULE_PATH_64 := $($(native_tests_var))/$(tests_dir_64)
 endif
 endif
 
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index e3ba227..8a3b6f3 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -1082,19 +1082,6 @@
   ASSERT_SUBSTR("libsysv-hash-table-library.so", dlinfo.dli_fname);
 }
 
-TEST(dlfcn, dlopen_library_with_ELF_TLS) {
-// TODO: Remove this test. Once ELF TLS is implemented, this test will be
-// replaced with a larger set of tests. Removing the test requires matching CLs
-// in CTS and in internal test suites.
-#if 0
-  dlerror(); // Clear any pending errors.
-  void* handle = dlopen("libelf-tls-library.so", RTLD_NOW);
-  ASSERT_TRUE(handle == nullptr);
-  ASSERT_SUBSTR("unknown reloc type ", dlerror());
-#endif
-  GTEST_LOG_(INFO) << "This test is disabled pending replacement with dynamic ELF TLS tests.\n";
-}
-
 TEST(dlfcn, dlopen_bad_flags) {
   dlerror(); // Clear any pending errors.
   void* handle;
diff --git a/tests/elftls_dl_test.cpp b/tests/elftls_dl_test.cpp
index 0a97c28..e908fb9 100644
--- a/tests/elftls_dl_test.cpp
+++ b/tests/elftls_dl_test.cpp
@@ -34,6 +34,10 @@
 #include "gtest_globals.h"
 #include "utils.h"
 
+#if defined(__BIONIC__)
+#include "bionic/pthread_internal.h"
+#endif
+
 // Access libtest_elftls_shared_var.so's TLS variable using an IE access.
 __attribute__((tls_model("initial-exec"))) extern "C" __thread int elftls_shared_var;
 
@@ -78,3 +82,175 @@
   eth.SetArgs({ helper.c_str(), nullptr });
   eth.Run([&]() { execve(helper.c_str(), eth.GetArgs(), eth.GetEnv()); }, 0, error.c_str());
 }
+
+// Use a GD access (__tls_get_addr or TLSDESC) to modify a variable in static
+// TLS memory.
+TEST(elftls_dl, access_static_tls) {
+  void* lib = dlopen("libtest_elftls_dynamic.so", RTLD_LOCAL | RTLD_NOW);
+  ASSERT_NE(nullptr, lib);
+
+  auto bump_shared_var = reinterpret_cast<int(*)()>(dlsym(lib, "bump_shared_var"));
+  ASSERT_NE(nullptr, bump_shared_var);
+
+  ASSERT_EQ(21, ++elftls_shared_var);
+  ASSERT_EQ(22, bump_shared_var());
+
+  std::thread([bump_shared_var] {
+    ASSERT_EQ(21, ++elftls_shared_var);
+    ASSERT_EQ(22, bump_shared_var());
+  }).join();
+}
+
+TEST(elftls_dl, bump_local_vars) {
+  void* lib = dlopen("libtest_elftls_dynamic.so", RTLD_LOCAL | RTLD_NOW);
+  ASSERT_NE(nullptr, lib);
+
+  auto bump_local_vars = reinterpret_cast<int(*)()>(dlsym(lib, "bump_local_vars"));
+  ASSERT_NE(nullptr, bump_local_vars);
+
+  ASSERT_EQ(42, bump_local_vars());
+  std::thread([bump_local_vars] {
+    ASSERT_EQ(42, bump_local_vars());
+  }).join();
+}
+
+// The behavior of accessing an unresolved weak TLS symbol using a dynamic TLS
+// relocation depends on which kind of implementation the target uses. With
+// TLSDESC, the result is NULL. With __tls_get_addr, the result is the
+// generation count (or maybe undefined behavior)? This test only tests TLSDESC.
+TEST(elftls_dl, missing_weak) {
+#if defined(__aarch64__)
+  void* lib = dlopen("libtest_elftls_dynamic.so", RTLD_LOCAL | RTLD_NOW);
+  ASSERT_NE(nullptr, lib);
+
+  auto missing_weak_dyn_tls_addr = reinterpret_cast<int*(*)()>(dlsym(lib, "missing_weak_dyn_tls_addr"));
+  ASSERT_NE(nullptr, missing_weak_dyn_tls_addr);
+
+  ASSERT_EQ(nullptr, missing_weak_dyn_tls_addr());
+  std::thread([missing_weak_dyn_tls_addr] {
+    ASSERT_EQ(nullptr, missing_weak_dyn_tls_addr());
+  }).join();
+#else
+  GTEST_LOG_(INFO) << "This test is only run on TLSDESC-based targets.\n";
+#endif
+}
+
+TEST(elftls_dl, dtv_resize) {
+#if defined(__BIONIC__)
+#define LOAD_LIB(soname) ({                           \
+    auto lib = dlopen(soname, RTLD_LOCAL | RTLD_NOW); \
+    ASSERT_NE(nullptr, lib);                          \
+    reinterpret_cast<int(*)()>(dlsym(lib, "bump"));   \
+  })
+
+  auto dtv = []() -> TlsDtv* { return __get_tcb_dtv(__get_bionic_tcb()); };
+
+  static_assert(sizeof(TlsDtv) == 3 * sizeof(void*),
+                "This test assumes that the Dtv has a 3-word header");
+
+  // Initially there are 3 modules:
+  //  - the main test executable
+  //  - libtest_elftls_shared_var
+  //  - libtest_elftls_tprel
+
+  // The initial DTV is an empty DTV with no generation and a size of 0.
+  TlsDtv* zero_dtv = dtv();
+  ASSERT_EQ(0u, zero_dtv->count);
+  ASSERT_EQ(nullptr, zero_dtv->next);
+  ASSERT_EQ(kTlsGenerationNone, zero_dtv->generation);
+
+  // Load the fourth module.
+  auto func1 = LOAD_LIB("libtest_elftls_dynamic_filler_1.so");
+  ASSERT_EQ(101, func1());
+
+  // After loading one module, the DTV should be initialized to the next
+  // power-of-2 size (including the header).
+  TlsDtv* initial_dtv = dtv();
+  ASSERT_EQ(5u, initial_dtv->count);
+  ASSERT_EQ(zero_dtv, initial_dtv->next);
+  ASSERT_LT(0u, initial_dtv->generation);
+
+  // Load module 5.
+  auto func2 = LOAD_LIB("libtest_elftls_dynamic_filler_2.so");
+  ASSERT_EQ(102, func1());
+  ASSERT_EQ(201, func2());
+  ASSERT_EQ(initial_dtv, dtv());
+  ASSERT_EQ(5u, initial_dtv->count);
+
+  // Load module 6.
+  auto func3 = LOAD_LIB("libtest_elftls_dynamic_filler_3.so");
+  ASSERT_EQ(103, func1());
+  ASSERT_EQ(202, func2());
+
+#if defined(__aarch64__)
+  // The arm64 TLSDESC resolver doesn't update the DTV if it is new enough for
+  // the given access.
+  ASSERT_EQ(5u, dtv()->count);
+#else
+  // __tls_get_addr updates the DTV anytime the generation counter changes.
+  ASSERT_EQ(13u, dtv()->count);
+#endif
+
+  ASSERT_EQ(301, func3());
+
+  TlsDtv* new_dtv = dtv();
+  ASSERT_EQ(13u, new_dtv->count);
+  ASSERT_NE(initial_dtv, new_dtv);
+  ASSERT_EQ(initial_dtv, new_dtv->next);
+
+#undef LOAD_LIB
+#else
+  GTEST_LOG_(INFO) << "This test is skipped for glibc because it tests Bionic internals.";
+#endif
+}
+
+// Verify that variables are reset to their initial values after the library
+// containing them is closed.
+TEST(elftls_dl, dlclose_resets_values) {
+  for (int round = 0; round < 2; ++round) {
+    void* lib = dlopen("libtest_elftls_dynamic.so", RTLD_LOCAL | RTLD_NOW);
+    ASSERT_NE(nullptr, lib);
+
+    auto bump_local_vars = reinterpret_cast<int(*)()>(dlsym(lib, "bump_local_vars"));
+    ASSERT_NE(nullptr, bump_local_vars);
+
+    ASSERT_EQ(42, bump_local_vars());
+    ASSERT_EQ(44, bump_local_vars());
+
+    ASSERT_EQ(0, dlclose(lib));
+  }
+}
+
+// Calling dlclose should remove the entry for the solib from the global list of
+// ELF TLS modules. Test that repeatedly loading and unloading a library doesn't
+// increase the DTV size.
+TEST(elftls_dl, dlclose_removes_entry) {
+#if defined(__BIONIC__)
+  auto dtv = []() -> TlsDtv* { return __get_tcb_dtv(__get_bionic_tcb()); };
+
+  bool first = true;
+  size_t count = 0;
+
+  // Use a large number of rounds in case the DTV is initially larger than
+  // expected.
+  for (int round = 0; round < 32; ++round) {
+    void* lib = dlopen("libtest_elftls_dynamic.so", RTLD_LOCAL | RTLD_NOW);
+    ASSERT_NE(nullptr, lib);
+
+    auto bump_local_vars = reinterpret_cast<int(*)()>(dlsym(lib, "bump_local_vars"));
+    ASSERT_NE(nullptr, bump_local_vars);
+
+    ASSERT_EQ(42, bump_local_vars());
+    if (first) {
+      first = false;
+      count = dtv()->count;
+    } else {
+      ASSERT_EQ(count, dtv()->count);
+    }
+
+    dlclose(lib);
+  }
+#else
+  GTEST_LOG_(INFO) << "This test is skipped for glibc because it tests Bionic internals.";
+#endif
+}
diff --git a/tests/elftls_test.cpp b/tests/elftls_test.cpp
index 11d41ce..2d83d70 100644
--- a/tests/elftls_test.cpp
+++ b/tests/elftls_test.cpp
@@ -83,3 +83,17 @@
     ASSERT_EQ(8, bump_static_tls_var_2());
   }).join();
 }
+
+// Because this C++ source file is built with -fpic, the compiler will access
+// this variable using a GD model. Typically, the static linker will relax the
+// GD to LE, but the arm32 linker doesn't do TLS relaxations, so we can test
+// calling __tls_get_addr in a static executable. The static linker knows that
+// the main executable's TlsIndex::module_id is 1 and writes that into the GOT.
+__thread int tlsvar_general = 30;
+
+TEST(elftls, general) {
+  ASSERT_EQ(31, ++tlsvar_general);
+  std::thread([] {
+    ASSERT_EQ(31, ++tlsvar_general);
+  }).join();
+}
diff --git a/tests/getauxval_test.cpp b/tests/getauxval_test.cpp
index 63bc963..aa21817 100644
--- a/tests/getauxval_test.cpp
+++ b/tests/getauxval_test.cpp
@@ -14,29 +14,14 @@
  * limitations under the License.
  */
 
+#include <sys/auxv.h>
+
 #include <errno.h>
 #include <sys/cdefs.h>
 #include <sys/utsname.h>
 #include <gtest/gtest.h>
 
-// getauxval() was only added as of glibc version 2.16.
-// See: http://lwn.net/Articles/519085/
-// Don't try to compile this code on older glibc versions.
-
-#if defined(__BIONIC__)
-  #define GETAUXVAL_CAN_COMPILE 1
-#elif defined(__GLIBC_PREREQ)
-  #if __GLIBC_PREREQ(2, 16)
-    #define GETAUXVAL_CAN_COMPILE 1
-  #endif
-#endif
-
-#if defined(GETAUXVAL_CAN_COMPILE)
-#include <sys/auxv.h>
-#endif
-
 TEST(getauxval, expected_values) {
-#if defined(GETAUXVAL_CAN_COMPILE)
   ASSERT_EQ(0UL, getauxval(AT_SECURE));
   ASSERT_EQ(getuid(), getauxval(AT_UID));
   ASSERT_EQ(geteuid(), getauxval(AT_EUID));
@@ -48,19 +33,12 @@
   ASSERT_NE(0UL, getauxval(AT_PHNUM));
   ASSERT_NE(0UL, getauxval(AT_ENTRY));
   ASSERT_NE(0UL, getauxval(AT_PAGESZ));
-#else
-  GTEST_LOG_(INFO) << "This test requires a C library with getauxval.\n";
-#endif
 }
 
 TEST(getauxval, unexpected_values) {
-#if defined(GETAUXVAL_CAN_COMPILE)
   errno = 0;
   ASSERT_EQ(0UL, getauxval(0xdeadbeef));
   ASSERT_EQ(ENOENT, errno);
-#else
-  GTEST_LOG_(INFO) << "This test requires a C library with getauxval.\n";
-#endif
 }
 
 TEST(getauxval, arm_has_AT_HWCAP2) {
diff --git a/tests/headers/posix/signal_h.c b/tests/headers/posix/signal_h.c
index 661b55e..c2e544e 100644
--- a/tests/headers/posix/signal_h.c
+++ b/tests/headers/posix/signal_h.c
@@ -53,7 +53,7 @@
   STRUCT_MEMBER(struct sigevent, int, sigev_signo);
   STRUCT_MEMBER(struct sigevent, union sigval, sigev_value);
   STRUCT_MEMBER_FUNCTION_POINTER(struct sigevent, void (*f)(union sigval), sigev_notify_function);
-#if defined(__BIONIC__) || defined(__GLIBC__)
+#if defined(__BIONIC__)
   STRUCT_MEMBER(struct sigevent, void*, sigev_notify_attributes);
 #else
   STRUCT_MEMBER(struct sigevent, pthread_attr_t*, sigev_notify_attributes);
diff --git a/tests/libs/elf_tls_test_library.cpp b/tests/ifunc_test.cpp
similarity index 67%
rename from tests/libs/elf_tls_test_library.cpp
rename to tests/ifunc_test.cpp
index 56d0171..7ab5899 100644
--- a/tests/libs/elf_tls_test_library.cpp
+++ b/tests/ifunc_test.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2018 The Android Open Source Project
+ * Copyright (C) 2019 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.
@@ -14,6 +14,18 @@
  * limitations under the License.
  */
 
-thread_local int elf_tls_variable;
+#include <gtest/gtest.h>
 
-extern "C" int* get() { return &elf_tls_variable; }
+int ret42() {
+  return 42;
+}
+
+extern "C" void* resolver() {
+  return (void*)ret42;
+}
+
+int ifunc() __attribute__((ifunc("resolver")));
+
+TEST(ifunc, function) {
+  ASSERT_EQ(42, ifunc());
+}
diff --git a/tests/libs/Android.bp b/tests/libs/Android.bp
index 05d1ed2..d58b6b8 100644
--- a/tests/libs/Android.bp
+++ b/tests/libs/Android.bp
@@ -43,14 +43,6 @@
 // Libraries and helper binaries for ELF TLS
 // -----------------------------------------------------------------------------
 cc_test_library {
-    name: "libelf-tls-library",
-    defaults: ["bionic_testlib_defaults"],
-    srcs: ["elf_tls_test_library.cpp"],
-    cflags: ["-fno-emulated-tls"],
-    allow_undefined_symbols: true, // __tls_get_addr is undefined.
-}
-
-cc_test_library {
     name: "libtest_elftls_shared_var",
     defaults: ["bionic_testlib_defaults"],
     srcs: ["elftls_shared_var.cpp"],
@@ -79,6 +71,35 @@
     ldflags: ["-Wl,--rpath,${ORIGIN}/.."],
 }
 
+cc_test_library {
+    name: "libtest_elftls_dynamic",
+    defaults: ["bionic_testlib_defaults"],
+    srcs: ["elftls_dynamic.cpp"],
+    cflags: ["-fno-emulated-tls"],
+    shared_libs: ["libtest_elftls_shared_var"],
+}
+
+cc_test_library {
+    name: "libtest_elftls_dynamic_filler_1",
+    defaults: ["bionic_testlib_defaults"],
+    srcs: ["elftls_dynamic_filler.cpp"],
+    cflags: ["-fno-emulated-tls", "-DTLS_FILLER=100"],
+}
+
+cc_test_library {
+    name: "libtest_elftls_dynamic_filler_2",
+    defaults: ["bionic_testlib_defaults"],
+    srcs: ["elftls_dynamic_filler.cpp"],
+    cflags: ["-fno-emulated-tls", "-DTLS_FILLER=200"],
+}
+
+cc_test_library {
+    name: "libtest_elftls_dynamic_filler_3",
+    defaults: ["bionic_testlib_defaults"],
+    srcs: ["elftls_dynamic_filler.cpp"],
+    cflags: ["-fno-emulated-tls", "-DTLS_FILLER=300"],
+}
+
 // -----------------------------------------------------------------------------
 // Library to test gnu-styled hash
 // -----------------------------------------------------------------------------
diff --git a/tests/libs/Android.build.dlext_testzip.mk b/tests/libs/Android.build.dlext_testzip.mk
index 19fd64b..8775c29 100644
--- a/tests/libs/Android.build.dlext_testzip.mk
+++ b/tests/libs/Android.build.dlext_testzip.mk
@@ -59,21 +59,38 @@
 lib_b := $(call intermediates-dir-for,SHARED_LIBRARIES,libtest_dt_runpath_b,,,$(bionic_2nd_arch_prefix))/libtest_dt_runpath_b.so
 lib_c := $(call intermediates-dir-for,SHARED_LIBRARIES,libtest_dt_runpath_c,,,$(bionic_2nd_arch_prefix))/libtest_dt_runpath_c.so
 lib_x := $(call intermediates-dir-for,SHARED_LIBRARIES,libtest_dt_runpath_x,,,$(bionic_2nd_arch_prefix))/libtest_dt_runpath_x.so
+lib_y := $(call intermediates-dir-for,SHARED_LIBRARIES,libtest_dt_runpath_y,,,$(bionic_2nd_arch_prefix))/libtest_dt_runpath_y.so
 
 $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_D := $(lib_d)
 $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_A := $(lib_a)
 $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_B := $(lib_b)
 $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_C := $(lib_c)
 $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_X := $(lib_x)
-$(LOCAL_BUILT_MODULE) : $(lib_d) $(lib_a) $(lib_b) $(lib_c) $(lib_x) $(BIONIC_TESTS_ZIPALIGN)
+$(LOCAL_BUILT_MODULE) : PRIVATE_LIB_Y := $(lib_y)
+ifeq ($(TARGET_IS_64_BIT),true)
+  ifeq ($(TARGET_TRANSLATE_2ND_ARCH),true)
+    $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_OR_LIB64 := $(if $(LOCAL_2ND_ARCH_VAR_PREFIX),lib/$(TARGET_2ND_ARCH),lib64)
+  else
+    $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_OR_LIB64 := $(if $(LOCAL_2ND_ARCH_VAR_PREFIX),lib,lib64)
+  endif
+else
+  ifeq ($(TARGET_TRANSLATE_2ND_ARCH),true)
+    $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_OR_LIB64 := $(if $(LOCAL_2ND_ARCH_VAR_PREFIX),lib/$(TARGET_2ND_ARCH),lib)
+  else
+    $(LOCAL_BUILT_MODULE) : PRIVATE_LIB_OR_LIB64 := lib
+  endif
+endif
+$(LOCAL_BUILT_MODULE) : $(lib_d) $(lib_a) $(lib_b) $(lib_c) $(lib_x) $(lib_y) $(BIONIC_TESTS_ZIPALIGN)
 	@echo "Aligning zip: $@"
 	$(hide) rm -rf $@.unaligned $@ $(dir $@)/zipdir && mkdir -p $(dir $@)/zipdir/libdir && \
-    mkdir -p $(dir $@)/zipdir/libdir/dt_runpath_a && mkdir -p $(dir $@)/zipdir/libdir/dt_runpath_b_c_x
+    mkdir -p $(dir $@)/zipdir/libdir/dt_runpath_a && mkdir -p $(dir $@)/zipdir/libdir/dt_runpath_b_c_x && \
+    mkdir -p $(dir $@)/zipdir/libdir/dt_runpath_y/$(PRIVATE_LIB_OR_LIB64)
 	$(hide) cp $(PRIVATE_LIB_D) $(dir $@)/zipdir/libdir
 	$(hide) cp $(PRIVATE_LIB_A) $(dir $@)/zipdir/libdir/dt_runpath_a
 	$(hide) cp $(PRIVATE_LIB_B) $(dir $@)/zipdir/libdir/dt_runpath_b_c_x
 	$(hide) cp $(PRIVATE_LIB_C) $(dir $@)/zipdir/libdir/dt_runpath_b_c_x
 	$(hide) cp $(PRIVATE_LIB_X) $(dir $@)/zipdir/libdir/dt_runpath_b_c_x
+	$(hide) cp $(PRIVATE_LIB_Y) $(dir $@)/zipdir/libdir/dt_runpath_y/$(PRIVATE_LIB_OR_LIB64)
 	$(hide) touch $(dir $@)/zipdir/empty_file.txt
 	$(hide) (cd $(dir $@)/zipdir && zip -qrD0 ../$(notdir $@).unaligned .)
 	$(hide) $(BIONIC_TESTS_ZIPALIGN) 4096 $@.unaligned $@
diff --git a/tests/libs/Android.build.dt_runpath.mk b/tests/libs/Android.build.dt_runpath.mk
index a3fcac5..b0d8e4b 100644
--- a/tests/libs/Android.build.dt_runpath.mk
+++ b/tests/libs/Android.build.dt_runpath.mk
@@ -21,11 +21,12 @@
 #
 # Dependencies
 #
-# libtest_dt_runpath_d.so                       runpath: ${ORIGIN}/dt_runpath_b_c_x
+# libtest_dt_runpath_d.so                       runpath: ${ORIGIN}/dt_runpath_b_c_x, ${ORIGIN}/dt_runpath_y/${LIB}
 # |-> dt_runpath_b_c_x/libtest_dt_runpath_b.so  runpath: ${ORIGIN}/../dt_runpath_a
 # |   |-> dt_runpath_a/libtest_dt_runpath_a.so
 # |-> dt_runpath_b_c_x/libtest_dt_runpath_c.so  runpath: ${ORIGIN}/invalid_dt_runpath
 # |   |-> libtest_dt_runpath_a.so (soname)
+# |-> dt_runpath_y/lib[64]/libtest_dt_runpath_y.so
 #
 # This one is used to test dlopen
 # dt_runpath_b_c_x/libtest_dt_runpath_x.so
@@ -61,12 +62,18 @@
 module := libtest_dt_runpath_c
 include $(LOCAL_PATH)/Android.build.testlib.mk
 
-# D depends on B and C with DT_RUNPATH.
+# D depends on B, C, and Y with DT_RUNPATH.
 libtest_dt_runpath_d_src_files := \
     dlopen_b.cpp
 
-libtest_dt_runpath_d_shared_libraries := libtest_dt_runpath_b libtest_dt_runpath_c
-libtest_dt_runpath_d_ldflags := -Wl,--rpath,\$${ORIGIN}/dt_runpath_b_c_x -Wl,--enable-new-dtags
+libtest_dt_runpath_d_shared_libraries := \
+    libtest_dt_runpath_b \
+    libtest_dt_runpath_c \
+    libtest_dt_runpath_y
+libtest_dt_runpath_d_ldflags := \
+    -Wl,--rpath,\$${ORIGIN}/dt_runpath_b_c_x \
+    -Wl,--rpath,\$${ORIGIN}/dt_runpath_y/\$${LIB} \
+    -Wl,--enable-new-dtags
 libtest_dt_runpath_d_ldlibs := -ldl
 module := libtest_dt_runpath_d
 include $(LOCAL_PATH)/Android.build.testlib.mk
@@ -77,8 +84,14 @@
 libtest_dt_runpath_d_zip_src_files := \
     dlopen_b.cpp
 
-libtest_dt_runpath_d_zip_shared_libraries := libtest_dt_runpath_b libtest_dt_runpath_c
-libtest_dt_runpath_d_zip_ldflags := -Wl,--rpath,\$${ORIGIN}/dt_runpath_b_c_x -Wl,--enable-new-dtags
+libtest_dt_runpath_d_zip_shared_libraries := \
+    libtest_dt_runpath_b \
+    libtest_dt_runpath_c \
+    libtest_dt_runpath_y
+libtest_dt_runpath_d_zip_ldflags := \
+    -Wl,--rpath,\$${ORIGIN}/dt_runpath_b_c_x \
+    -Wl,--rpath,\$${ORIGIN}/dt_runpath_y/\$${LIB} \
+    -Wl,--enable-new-dtags
 libtest_dt_runpath_d_zip_ldlibs := -ldl
 libtest_dt_runpath_d_zip_install_to_native_tests_dir := $(module)
 
@@ -96,3 +109,20 @@
 module := libtest_dt_runpath_x
 include $(LOCAL_PATH)/Android.build.testlib.mk
 
+# A leaf library in lib or lib64 directory
+libtest_dt_runpath_y_src_files := \
+    empty.cpp
+
+ifeq ($(TARGET_TRANSLATE_2ND_ARCH),true)
+libtest_dt_runpath_y_install_to_native_tests_dir_32 := bionic-loader-test-libs/dt_runpath_y/lib/$(TARGET_2ND_ARCH)
+else
+libtest_dt_runpath_y_install_to_native_tests_dir_32 := bionic-loader-test-libs/dt_runpath_y/lib
+endif
+ifeq ($(TARGET_IS_64_BIT),true)
+libtest_dt_runpath_y_install_to_native_tests_dir_64 := bionic-loader-test-libs/dt_runpath_y/lib64
+else
+libtest_dt_runpath_y_install_to_native_tests_dir_64 := bionic-loader-test-libs/dt_runpath_y/lib
+endif
+
+module := libtest_dt_runpath_y
+include $(LOCAL_PATH)/Android.build.testlib.mk
diff --git a/tests/libs/elftls_dynamic.cpp b/tests/libs/elftls_dynamic.cpp
new file mode 100644
index 0000000..7fa239c
--- /dev/null
+++ b/tests/libs/elftls_dynamic.cpp
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+// This shared object test library is dlopen'ed by the main test executable.
+// This variable comes from libtest_elftls_shared_var.so, which is part of
+// static TLS. Verify that a GD-model access can access the variable.
+//
+// Accessing the static TLS variable from an solib prevents the static linker
+// from relaxing the GD access to IE and lets us test that __tls_get_addr and
+// the tlsdesc resolver handle a static TLS variable.
+extern "C" __thread int elftls_shared_var;
+
+extern "C" int bump_shared_var() {
+  return ++elftls_shared_var;
+}
+
+// The static linker denotes the current module by omitting the symbol from
+// the DTPMOD/TLSDESC relocations.
+static __thread int local_var_1 = 15;
+static __thread int local_var_2 = 25;
+
+extern "C" int bump_local_vars() {
+  return ++local_var_1 + ++local_var_2;
+}
+
+__attribute__((weak)) extern "C" __thread int missing_weak_dyn_tls;
+
+extern "C" int* missing_weak_dyn_tls_addr() {
+  return &missing_weak_dyn_tls;
+}
diff --git a/tests/libs/elftls_dynamic_filler.cpp b/tests/libs/elftls_dynamic_filler.cpp
new file mode 100644
index 0000000..9c00ab0
--- /dev/null
+++ b/tests/libs/elftls_dynamic_filler.cpp
@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+__thread int var = TLS_FILLER;
+
+extern "C" int bump() {
+  return ++var;
+}
diff --git a/tests/pthread_test.cpp b/tests/pthread_test.cpp
index 1c57264..8da54ce 100644
--- a/tests/pthread_test.cpp
+++ b/tests/pthread_test.cpp
@@ -25,6 +25,7 @@
 #include <stdio.h>
 #include <sys/mman.h>
 #include <sys/prctl.h>
+#include <sys/resource.h>
 #include <sys/syscall.h>
 #include <time.h>
 #include <unistd.h>
@@ -336,11 +337,14 @@
   static void* thread_fn(void* arg) {
     TestBug37410* data = reinterpret_cast<TestBug37410*>(arg);
 
+    // Unlocking data->mutex will cause the main thread to exit, invalidating *data. Save the handle.
+    pthread_t main_thread = data->main_thread;
+
     // Let the main thread know we're running.
     pthread_mutex_unlock(&data->mutex);
 
     // And wait for the main thread to exit.
-    pthread_join(data->main_thread, nullptr);
+    pthread_join(main_thread, nullptr);
 
     return nullptr;
   }
@@ -494,7 +498,8 @@
   pthread_t dead_thread;
   MakeDeadThread(dead_thread);
 
-  EXPECT_DEATH(pthread_setname_np(dead_thread, "short 3"), "invalid pthread_t");
+  EXPECT_DEATH(pthread_setname_np(dead_thread, "short 3"),
+               "invalid pthread_t (.*) passed to pthread_setname_np");
 }
 
 TEST_F(pthread_DeathTest, pthread_setname_np__null_thread) {
@@ -507,7 +512,8 @@
   MakeDeadThread(dead_thread);
 
   char name[64];
-  EXPECT_DEATH(pthread_getname_np(dead_thread, name, sizeof(name)), "invalid pthread_t");
+  EXPECT_DEATH(pthread_getname_np(dead_thread, name, sizeof(name)),
+               "invalid pthread_t (.*) passed to pthread_getname_np");
 }
 
 TEST_F(pthread_DeathTest, pthread_getname_np__null_thread) {
@@ -563,7 +569,8 @@
   pthread_t dead_thread;
   MakeDeadThread(dead_thread);
 
-  EXPECT_DEATH(pthread_detach(dead_thread), "invalid pthread_t");
+  EXPECT_DEATH(pthread_detach(dead_thread),
+               "invalid pthread_t (.*) passed to pthread_detach");
 }
 
 TEST_F(pthread_DeathTest, pthread_detach__null_thread) {
@@ -590,7 +597,8 @@
   MakeDeadThread(dead_thread);
 
   clockid_t c;
-  EXPECT_DEATH(pthread_getcpuclockid(dead_thread, &c), "invalid pthread_t");
+  EXPECT_DEATH(pthread_getcpuclockid(dead_thread, &c),
+               "invalid pthread_t (.*) passed to pthread_getcpuclockid");
 }
 
 TEST_F(pthread_DeathTest, pthread_getcpuclockid__null_thread) {
@@ -605,7 +613,8 @@
 
   int policy;
   sched_param param;
-  EXPECT_DEATH(pthread_getschedparam(dead_thread, &policy, &param), "invalid pthread_t");
+  EXPECT_DEATH(pthread_getschedparam(dead_thread, &policy, &param),
+               "invalid pthread_t (.*) passed to pthread_getschedparam");
 }
 
 TEST_F(pthread_DeathTest, pthread_getschedparam__null_thread) {
@@ -621,7 +630,8 @@
 
   int policy = 0;
   sched_param param;
-  EXPECT_DEATH(pthread_setschedparam(dead_thread, policy, &param), "invalid pthread_t");
+  EXPECT_DEATH(pthread_setschedparam(dead_thread, policy, &param),
+               "invalid pthread_t (.*) passed to pthread_setschedparam");
 }
 
 TEST_F(pthread_DeathTest, pthread_setschedparam__null_thread) {
@@ -635,7 +645,8 @@
   pthread_t dead_thread;
   MakeDeadThread(dead_thread);
 
-  EXPECT_DEATH(pthread_setschedprio(dead_thread, 123), "invalid pthread_t");
+  EXPECT_DEATH(pthread_setschedprio(dead_thread, 123),
+               "invalid pthread_t (.*) passed to pthread_setschedprio");
 }
 
 TEST_F(pthread_DeathTest, pthread_setschedprio__null_thread) {
@@ -647,7 +658,8 @@
   pthread_t dead_thread;
   MakeDeadThread(dead_thread);
 
-  EXPECT_DEATH(pthread_join(dead_thread, nullptr), "invalid pthread_t");
+  EXPECT_DEATH(pthread_join(dead_thread, nullptr),
+               "invalid pthread_t (.*) passed to pthread_join");
 }
 
 TEST_F(pthread_DeathTest, pthread_join__null_thread) {
@@ -659,7 +671,8 @@
   pthread_t dead_thread;
   MakeDeadThread(dead_thread);
 
-  EXPECT_DEATH(pthread_kill(dead_thread, 0), "invalid pthread_t");
+  EXPECT_DEATH(pthread_kill(dead_thread, 0),
+               "invalid pthread_t (.*) passed to pthread_kill");
 }
 
 TEST_F(pthread_DeathTest, pthread_kill__null_thread) {
diff --git a/tests/stdio_test.cpp b/tests/stdio_test.cpp
index 479fd9d..ad6ed45 100644
--- a/tests/stdio_test.cpp
+++ b/tests/stdio_test.cpp
@@ -1820,6 +1820,14 @@
   ASSERT_EQ(0, fclose(fp));
 }
 
+TEST(STDIO_TEST, fmemopen_zero_length_buffer_overrun) {
+  char buf[2] = "x";
+  ASSERT_EQ('x', buf[0]);
+  FILE* fp = fmemopen(buf, 0, "w");
+  ASSERT_EQ('x', buf[0]);
+  ASSERT_EQ(0, fclose(fp));
+}
+
 TEST(STDIO_TEST, fmemopen_write_only_allocated) {
   // POSIX says fmemopen "may fail if the mode argument does not include a '+'".
   // BSD fails, glibc doesn't. We side with the more lenient.
diff --git a/tests/stdlib_test.cpp b/tests/stdlib_test.cpp
index a249b75..408a9c7 100644
--- a/tests/stdlib_test.cpp
+++ b/tests/stdlib_test.cpp
@@ -36,14 +36,6 @@
 #include "math_data_test.h"
 #include "utils.h"
 
-#if defined(__BIONIC__)
-  #define ALIGNED_ALLOC_AVAILABLE 1
-#elif defined(__GLIBC_PREREQ)
-  #if __GLIBC_PREREQ(2, 16)
-    #define ALIGNED_ALLOC_AVAILABLE 1
-  #endif
-#endif
-
 template <typename T = int (*)(char*)>
 class GenericTemporaryFile {
  public:
@@ -274,7 +266,6 @@
 
 TEST(stdlib, aligned_alloc_sweep) {
   SKIP_WITH_HWASAN;
-#if defined(ALIGNED_ALLOC_AVAILABLE)
   // Verify powers of 2 up to 2048 allocate, and verify that all other
   // alignment values between the powers of 2 fail.
   size_t last_align = 1;
@@ -292,31 +283,20 @@
     free(ptr);
     last_align = align;
   }
-#else
-  GTEST_LOG_(INFO) << "This test requires a C library that has aligned_alloc.\n";
-#endif
 }
 
 TEST(stdlib, aligned_alloc_overflow) {
   SKIP_WITH_HWASAN;
-#if defined(ALIGNED_ALLOC_AVAILABLE)
   ASSERT_TRUE(aligned_alloc(16, SIZE_MAX) == nullptr);
-#else
-  GTEST_LOG_(INFO) << "This test requires a C library that has aligned_alloc.\n";
-#endif
 }
 
 TEST(stdlib, aligned_alloc_size_not_multiple_of_alignment) {
   SKIP_WITH_HWASAN;
-#if defined(ALIGNED_ALLOC_AVAILABLE)
   for (size_t size = 1; size <= 2048; size++) {
     void* ptr = aligned_alloc(2048, size);
     ASSERT_TRUE(ptr != nullptr) << "Failed at size " << std::to_string(size);
     free(ptr);
   }
-#else
-  GTEST_LOG_(INFO) << "This test requires a C library that has aligned_alloc.\n";
-#endif
 }
 
 TEST(stdlib, realpath__NULL_filename) {
diff --git a/tests/string_test.cpp b/tests/string_test.cpp
index fd2a787..b27ca87 100644
--- a/tests/string_test.cpp
+++ b/tests/string_test.cpp
@@ -1554,3 +1554,40 @@
   ASSERT_EQ(haystack + 1, strstr(haystack, "i"));
   ASSERT_EQ(haystack + 4, strstr(haystack, "da"));
 }
+
+TEST(STRING_TEST, strcasestr_smoke) {
+  const char* haystack = "bIg dAdDy/gIaNt hAyStAcKs";
+  ASSERT_EQ(haystack, strcasestr(haystack, ""));
+  ASSERT_EQ(haystack + 0, strcasestr(haystack, "B"));
+  ASSERT_EQ(haystack + 1, strcasestr(haystack, "i"));
+  ASSERT_EQ(haystack + 4, strcasestr(haystack, "Da"));
+}
+
+TEST(STRING_TEST, strcoll_smoke) {
+  ASSERT_TRUE(strcoll("aab", "aac") < 0);
+  ASSERT_TRUE(strcoll("aab", "aab") == 0);
+  ASSERT_TRUE(strcoll("aac", "aab") > 0);
+}
+
+TEST(STRING_TEST, strxfrm_smoke) {
+  const char* src1 = "aab";
+  char dst1[16] = {};
+  ASSERT_GT(strxfrm(dst1, src1, sizeof(dst1)), 0U);
+  const char* src2 = "aac";
+  char dst2[16] = {};
+  ASSERT_GT(strxfrm(dst2, src2, sizeof(dst2)), 0U);
+  ASSERT_TRUE(strcmp(dst1, dst2) < 0);
+}
+
+TEST(STRING_TEST, memccpy_smoke) {
+  char dst[32];
+
+  memset(dst, 0, sizeof(dst));
+  char* p = static_cast<char*>(memccpy(dst, "hello world", ' ', 32));
+  ASSERT_STREQ("hello ", dst);
+  ASSERT_EQ(ptrdiff_t(6), p - dst);
+
+  memset(dst, 0, sizeof(dst));
+  ASSERT_EQ(nullptr, memccpy(dst, "hello world", ' ', 4));
+  ASSERT_STREQ("hell", dst);
+}
diff --git a/tests/uchar_test.cpp b/tests/uchar_test.cpp
index 522d5ac..48c500d 100644
--- a/tests/uchar_test.cpp
+++ b/tests/uchar_test.cpp
@@ -15,12 +15,7 @@
  */
 
 
-#include <sys/cdefs.h>
-#if defined(__BIONIC__)
-#define HAVE_UCHAR 1
-#elif defined(__GLIBC__)
-#define HAVE_UCHAR __GLIBC_PREREQ(2, 16)
-#endif
+#include <uchar.h>
 
 #include <gtest/gtest.h>
 
@@ -29,21 +24,12 @@
 #include <locale.h>
 #include <stdint.h>
 
-#if HAVE_UCHAR
-#include <uchar.h>
-#endif
-
 TEST(uchar, sizeof_uchar_t) {
-#if HAVE_UCHAR
   EXPECT_EQ(2U, sizeof(char16_t));
   EXPECT_EQ(4U, sizeof(char32_t));
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, start_state) {
-#if HAVE_UCHAR
   char out[MB_LEN_MAX];
   mbstate_t ps;
 
@@ -64,31 +50,19 @@
   EXPECT_EQ(static_cast<size_t>(-2), mbrtoc32(nullptr, "\xf0\xa4", 1, &ps));
   EXPECT_EQ(1U, c32rtomb(out, L'\0', &ps));
   EXPECT_TRUE(mbsinit(&ps));
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, c16rtomb_null_out) {
-#if HAVE_UCHAR
   EXPECT_EQ(1U, c16rtomb(nullptr, L'\0', nullptr));
   EXPECT_EQ(1U, c16rtomb(nullptr, L'h', nullptr));
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, c16rtomb_null_char) {
-#if HAVE_UCHAR
   char bytes[MB_LEN_MAX];
   EXPECT_EQ(1U, c16rtomb(bytes, L'\0', nullptr));
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, c16rtomb) {
-#if HAVE_UCHAR
   char bytes[MB_LEN_MAX];
 
   memset(bytes, 0, sizeof(bytes));
@@ -113,13 +87,9 @@
   EXPECT_EQ('\xe2', bytes[0]);
   EXPECT_EQ('\x82', bytes[1]);
   EXPECT_EQ('\xac', bytes[2]);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, c16rtomb_surrogate) {
-#if HAVE_UCHAR
   char bytes[MB_LEN_MAX];
 
   memset(bytes, 0, sizeof(bytes));
@@ -129,13 +99,9 @@
   EXPECT_EQ('\x8a', bytes[1]);
   EXPECT_EQ('\xaf', bytes[2]);
   EXPECT_EQ('\x8d', bytes[3]);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, c16rtomb_invalid) {
-#if HAVE_UCHAR
   char bytes[MB_LEN_MAX];
 
   memset(bytes, 0, sizeof(bytes));
@@ -143,21 +109,13 @@
 
   EXPECT_EQ(0U, c16rtomb(bytes, 0xdbea, nullptr));
   EXPECT_EQ(static_cast<size_t>(-1), c16rtomb(bytes, 0xdbea, nullptr));
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc16_null) {
-#if HAVE_UCHAR
   ASSERT_EQ(0U, mbrtoc16(nullptr, nullptr, 0, nullptr));
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc16_zero_len) {
-#if HAVE_UCHAR
   char16_t out;
 
   out = L'x';
@@ -168,13 +126,9 @@
   ASSERT_EQ(0U, mbrtoc16(&out, "", 0, nullptr));
   ASSERT_EQ(1U, mbrtoc16(&out, "hello", 1, nullptr));
   ASSERT_EQ(L'h', out);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc16) {
-#if HAVE_UCHAR
   char16_t out;
 
   ASSERT_STREQ("C.UTF-8", setlocale(LC_CTYPE, "C.UTF-8"));
@@ -189,13 +143,9 @@
   // 3-byte UTF-8.
   ASSERT_EQ(3U, mbrtoc16(&out, "\xe2\x82\xac" "def", 6, nullptr));
   ASSERT_EQ(static_cast<char16_t>(0x20ac), out);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc16_surrogate) {
-#if HAVE_UCHAR
   char16_t out;
 
   ASSERT_EQ(static_cast<size_t>(-3),
@@ -203,32 +153,20 @@
   ASSERT_EQ(static_cast<char16_t>(0xdbea), out);
   ASSERT_EQ(4U, mbrtoc16(&out, "\xf4\x8a\xaf\x8d" "ef", 6, nullptr));
   ASSERT_EQ(static_cast<char16_t>(0xdfcd), out);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc16_reserved_range) {
-#if HAVE_UCHAR
   char16_t out;
   ASSERT_EQ(static_cast<size_t>(-1),
             mbrtoc16(&out, "\xf0\x80\xbf\xbf", 6, nullptr));
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc16_beyond_range) {
-#if HAVE_UCHAR
   char16_t out;
   ASSERT_EQ(static_cast<size_t>(-1),
             mbrtoc16(&out, "\xf5\x80\x80\x80", 6, nullptr));
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
-#if HAVE_UCHAR
 void test_mbrtoc16_incomplete(mbstate_t* ps) {
   ASSERT_STREQ("C.UTF-8", setlocale(LC_CTYPE, "C.UTF-8"));
   uselocale(LC_GLOBAL_LOCALE);
@@ -259,22 +197,16 @@
   ASSERT_EQ(static_cast<size_t>(-1), mbrtoc16(&out, "\x20" "cdef", 5, ps));
   ASSERT_EQ(EILSEQ, errno);
 }
-#endif
 
 TEST(uchar, mbrtoc16_incomplete) {
-#if HAVE_UCHAR
   mbstate_t ps;
   memset(&ps, 0, sizeof(ps));
 
   test_mbrtoc16_incomplete(&ps);
   test_mbrtoc16_incomplete(nullptr);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, c32rtomb) {
-#if HAVE_UCHAR
   EXPECT_EQ(1U, c32rtomb(nullptr, L'\0', nullptr));
   EXPECT_EQ(1U, c32rtomb(nullptr, L'h', nullptr));
 
@@ -317,13 +249,9 @@
   // Invalid code point.
   EXPECT_EQ(static_cast<size_t>(-1), c32rtomb(bytes, 0xffffffff, nullptr));
   EXPECT_EQ(EILSEQ, errno);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc32_valid_non_characters) {
-#if HAVE_UCHAR
   ASSERT_STREQ("C.UTF-8", setlocale(LC_CTYPE, "C.UTF-8"));
   uselocale(LC_GLOBAL_LOCALE);
 
@@ -332,13 +260,9 @@
   ASSERT_EQ(0xfffeU, out[0]);
   ASSERT_EQ(3U, mbrtoc32(out, "\xef\xbf\xbf", 3, nullptr));
   ASSERT_EQ(0xffffU, out[0]);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc32_out_of_range) {
-#if HAVE_UCHAR
   ASSERT_STREQ("C.UTF-8", setlocale(LC_CTYPE, "C.UTF-8"));
   uselocale(LC_GLOBAL_LOCALE);
 
@@ -346,13 +270,9 @@
   errno = 0;
   ASSERT_EQ(static_cast<size_t>(-1), mbrtoc32(out, "\xf5\x80\x80\x80", 4, nullptr));
   ASSERT_EQ(EILSEQ, errno);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
 TEST(uchar, mbrtoc32) {
-#if HAVE_UCHAR
   char32_t out[8];
 
   out[0] = L'x';
@@ -393,12 +313,8 @@
   // Illegal over-long sequence.
   ASSERT_EQ(static_cast<size_t>(-1), mbrtoc32(out, "\xf0\x82\x82\xac" "ef", 6, nullptr));
   ASSERT_EQ(EILSEQ, errno);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }
 
-#if HAVE_UCHAR
 void test_mbrtoc32_incomplete(mbstate_t* ps) {
   ASSERT_STREQ("C.UTF-8", setlocale(LC_CTYPE, "C.UTF-8"));
   uselocale(LC_GLOBAL_LOCALE);
@@ -427,16 +343,11 @@
   ASSERT_EQ(static_cast<size_t>(-1), mbrtoc32(&out, "\x20" "cdef", 5, ps));
   ASSERT_EQ(EILSEQ, errno);
 }
-#endif
 
 TEST(uchar, mbrtoc32_incomplete) {
-#if HAVE_UCHAR
   mbstate_t ps;
   memset(&ps, 0, sizeof(ps));
 
   test_mbrtoc32_incomplete(&ps);
   test_mbrtoc32_incomplete(nullptr);
-#else
-  GTEST_LOG_(INFO) << "uchar.h is unavailable.\n";
-#endif
 }