Clean up the pthread_create trampoline.

Bug: 8206355
Bug: 11693195
Change-Id: I35cc024d5b6ebd19d1d2e45610db185addaf45df

5 files changed, 28 insertions, 66 deletions

diff --git a/libc/Android.mk b/libc/Android.mk
index b24320d..aad6b04 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -289,7 +289,6 @@ libc_bionic_src_files := \
     bionic/sysconf.cpp \
     bionic/thread_atexit.cpp \
     bionic/tdestroy.cpp \
-    bionic/__thread_entry.cpp \
     bionic/timer.cpp \
     bionic/tmpfile.cpp \
     bionic/unlink.cpp \
diff --git a/libc/bionic/__thread_entry.cpp b/libc/bionic/__thread_entry.cpp
deleted file mode 100644
index 3505f8b..0000000
--- a/libc/bionic/__thread_entry.cpp
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Copyright (C) 2008 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 <pthread.h>
-
-#include "pthread_internal.h"
-
-#include "private/bionic_tls.h"
-
-// This trampoline is called from the assembly __bionic_clone function.
-int __thread_entry(void* arg) {
-  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(arg);
-
-  // Wait for our creating thread to release us. This lets it have time to
-  // notify gdb about this thread before we start doing anything.
-  // This also provides the memory barrier needed to ensure that all memory
-  // accesses previously made by the creating thread are visible to us.
-  pthread_mutex_t* start_mutex = (pthread_mutex_t*) &thread->tls[TLS_SLOT_START_MUTEX];
-  pthread_mutex_lock(start_mutex);
-  pthread_mutex_destroy(start_mutex);
-
-  __init_tls(thread);
-
-  __init_alternate_signal_stack(thread);
-
-  if ((thread->internal_flags & PTHREAD_INTERNAL_FLAG_THREAD_INIT_FAILED) != 0) {
-    pthread_exit(NULL);
-  }
-
-  void* result = thread->start_routine(thread->start_routine_arg);
-  pthread_exit(result);
-
-  return 0;
-}
diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
index 386e8d1..6ed01ff 100644
--- a/libc/bionic/pthread_create.cpp
+++ b/libc/bionic/pthread_create.cpp
@@ -134,6 +134,31 @@ static void* __create_thread_stack(pthread_internal_t* thread) {
   return stack;
 }
 
+static int __pthread_start(void* arg) {
+  pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(arg);
+
+  // Wait for our creating thread to release us. This lets it have time to
+  // notify gdb about this thread before we start doing anything.
+  // This also provides the memory barrier needed to ensure that all memory
+  // accesses previously made by the creating thread are visible to us.
+  pthread_mutex_t* start_mutex = (pthread_mutex_t*) &thread->tls[TLS_SLOT_START_MUTEX];
+  pthread_mutex_lock(start_mutex);
+  pthread_mutex_destroy(start_mutex);
+
+  __init_tls(thread);
+
+  __init_alternate_signal_stack(thread);
+
+  if ((thread->internal_flags & PTHREAD_INTERNAL_FLAG_THREAD_INIT_FAILED) != 0) {
+    pthread_exit(NULL);
+  }
+
+  void* result = thread->start_routine(thread->start_routine_arg);
+  pthread_exit(result);
+
+  return 0;
+}
+
 int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
                    void* (*start_routine)(void*), void* arg) {
   ErrnoRestorer errno_restorer;
@@ -198,7 +223,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
   thread->start_routine_arg = arg;
 
   int flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS;
-  int tid = __bionic_clone(flags, child_stack, NULL, thread->tls, NULL, __thread_entry, thread);
+  int tid = __bionic_clone(flags, child_stack, NULL, thread->tls, NULL, __pthread_start, thread);
   if (tid < 0) {
     int clone_errno = errno;
     if ((thread->attr.flags & PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK) == 0) {
@@ -213,7 +238,7 @@ int pthread_create(pthread_t* thread_out, pthread_attr_t const* attr,
 
   int init_errno = _init_thread(thread, true);
   if (init_errno != 0) {
-    // Mark the thread detached and let its __thread_entry run to
+    // Mark the thread detached and let its __pthread_start run to
     // completion. (It'll just exit immediately, cleaning up its resources.)
     thread->internal_flags |= PTHREAD_INTERNAL_FLAG_THREAD_INIT_FAILED;
     thread->attr.flags |= PTHREAD_ATTR_FLAG_DETACHED;
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index 52cfbce..d8ad544 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -55,9 +55,6 @@ struct pthread_internal_t {
     char dlerror_buffer[__BIONIC_DLERROR_BUFFER_SIZE];
 };
 
-extern "C" {
-  __LIBC_HIDDEN__ int __thread_entry(void* arg); // Called from assembler.
-}
 __LIBC_HIDDEN__ int _init_thread(pthread_internal_t* thread, bool add_to_thread_list);
 __LIBC_HIDDEN__ void __init_tls(pthread_internal_t* thread);
 __LIBC_HIDDEN__ void __init_alternate_signal_stack(pthread_internal_t*);
diff --git a/libc/bionic/pthread_key.cpp b/libc/bionic/pthread_key.cpp
index 440a715..f2f4d20 100644
--- a/libc/bionic/pthread_key.cpp
+++ b/libc/bionic/pthread_key.cpp
@@ -215,7 +215,7 @@ int pthread_key_delete(pthread_key_t key) {
     // Skip zombie threads. They don't have a valid TLS area any more.
     // Similarly, it is possible to have t->tls == NULL for threads that
     // were just recently created through pthread_create() but whose
-    // startup trampoline (__thread_entry) hasn't been run yet by the
+    // startup trampoline (__pthread_start) hasn't been run yet by the
     // scheduler. t->tls will also be NULL after a thread's stack has been
     // unmapped but before the ongoing pthread_join() is finished.
     if ((t->attr.flags & PTHREAD_ATTR_FLAG_ZOMBIE) || t->tls == NULL) {