Backed out 3 changesets (bug 1752703) for causing spider-monkey bustages.

Backed out changeset 6b8d96806ae6 (bug 1752703)
Backed out changeset afbd8f714804 (bug 1752703)
Backed out changeset 1adb41e2eb9b (bug 1752703)

browser/app/moz.build

@@ -53,6 +53,11 @@ LOCAL_INCLUDES += [
     "/xpcom/build",
 ]
 
+# The pthred_create() interposer needs to be linked as early as possible so
+# that it will appear before libpthread when resolving symbols.
+if CONFIG["OS_ARCH"] == "Linux" and CONFIG["MOZ_CRASHREPORTER"]:
+    USE_LIBS += ["pthread_create_interposer"]
+
 if CONFIG["LIBFUZZER"]:
     USE_LIBS += ["fuzzer"]
     LOCAL_INCLUDES += [

ipc/app/moz.build

@@ -16,6 +16,11 @@ else:
         "MozillaRuntimeMain.cpp",
     ]
 
+# The pthred_create() interposer needs to be linked as early as possible so
+# that it will appear before libpthread when resolving symbols.
+if CONFIG["OS_ARCH"] == "Linux" and CONFIG["MOZ_CRASHREPORTER"]:
+    USE_LIBS += ["pthread_create_interposer"]
+
 include("/ipc/chromium/chromium-config.mozbuild")
 
 LOCAL_INCLUDES += [

js/xpconnect/shell/moz.build

@@ -10,6 +10,11 @@ SOURCES += [
     "xpcshell.cpp",
 ]
 
+# The pthred_create() interposer needs to be linked as early as possible so
+# that it will appear before libpthread when resolving symbols.
+if CONFIG["OS_ARCH"] == "Linux" and CONFIG["MOZ_CRASHREPORTER"]:
+    USE_LIBS += ["pthread_create_interposer"]
+
 if CONFIG["LIBFUZZER"]:
     USE_LIBS += ["fuzzer"]
 

mozglue/interposers/InterposerHelper.h

@@ -1,41 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef InterposerHelper_h
-#define InterposerHelper_h
-
-#include <type_traits>
-
-#include <dlfcn.h>
-
-#include "mozilla/Assertions.h"
-
-template <typename T>
-static T get_real_symbol(const char* aName, T aReplacementSymbol) {
-  // T can only be a function pointer
-  static_assert(std::is_function<typename std::remove_pointer<T>::type>::value);
-
-  // Find the corresponding function in the linked libraries
-  T real_symbol = reinterpret_cast<T>(dlsym(RTLD_NEXT, aName));
-
-  if (real_symbol == nullptr) {
-    MOZ_CRASH_UNSAFE_PRINTF(
-        "%s() interposition failed but the interposer function is "
-        "still being called, this won't work!",
-        aName);
-  }
-
-  if (real_symbol == aReplacementSymbol) {
-    MOZ_CRASH_UNSAFE_PRINTF(
-        "We could not obtain the real %s(). Calling the symbol we "
-        "got would make us enter an infinite loop so stop here instead.",
-        aName);
-  }
-
-  return real_symbol;
-}
-
-#define GET_REAL_SYMBOL(name) get_real_symbol(#name, name)
-
-#endif  // InterposerHelper_h

mozglue/interposers/env_interposer.cpp

@@ -1,62 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include <pthread.h>
-
-#include "InterposerHelper.h"
-
-// The interposers in this file cover all the functions used to access the
-// environment (getenv(), putenv(), setenv(), unsetenv() and clearenv()). They
-// all use the mutex below for synchronization to prevent races that caused
-// startup crashes, see bug 1752703.
-static pthread_mutex_t gEnvLock = PTHREAD_MUTEX_INITIALIZER;
-
-extern "C" {
-
-MFBT_API char* getenv(const char* name) {
-  static const auto real_getenv = GET_REAL_SYMBOL(getenv);
-
-  pthread_mutex_lock(&gEnvLock);
-  char* result = real_getenv(name);
-  pthread_mutex_unlock(&gEnvLock);
-  return result;
-}
-
-MFBT_API int putenv(char* string) {
-  static const auto real_putenv = GET_REAL_SYMBOL(putenv);
-
-  pthread_mutex_lock(&gEnvLock);
-  int result = real_putenv(string);
-  pthread_mutex_unlock(&gEnvLock);
-  return result;
-}
-
-MFBT_API int setenv(const char* name, const char* value, int replace) {
-  static const auto real_setenv = GET_REAL_SYMBOL(setenv);
-
-  pthread_mutex_lock(&gEnvLock);
-  int result = real_setenv(name, value, replace);
-  pthread_mutex_unlock(&gEnvLock);
-  return result;
-}
-
-MFBT_API int unsetenv(const char* name) {
-  static const auto real_unsetenv = GET_REAL_SYMBOL(unsetenv);
-
-  pthread_mutex_lock(&gEnvLock);
-  int result = real_unsetenv(name);
-  pthread_mutex_unlock(&gEnvLock);
-  return result;
-}
-
-MFBT_API int clearenv(void) {
-  static const auto real_clearenv = GET_REAL_SYMBOL(clearenv);
-
-  pthread_mutex_lock(&gEnvLock);
-  int result = real_clearenv();
-  pthread_mutex_unlock(&gEnvLock);
-  return result;
-}
-
-}  // extern "C"

mozglue/moz.build

@@ -13,9 +13,6 @@ if CONFIG["MOZ_LINKER"] or CONFIG["MOZ_WIDGET_TOOLKIT"] == "android":
 if CONFIG["MOZ_WIDGET_TOOLKIT"] == "android":
     DIRS += ["android"]
 
-if CONFIG["OS_ARCH"] == "Linux":
-    DIRS += ["interposers"]
-
 DIRS += [
     "baseprofiler",
     "build",

toolkit/crashreporter/moz.build

@@ -53,6 +53,7 @@ if CONFIG["MOZ_CRASHREPORTER"]:
             "google-breakpad/src/common",
             "google-breakpad/src/common/linux",
             "google-breakpad/src/processor",
+            "pthread_create_interposer",
         ]
 
         if CONFIG["MOZ_OXIDIZED_BREAKPAD"]:

toolkit/crashreporter/pthread_create_interposer/moz.build

@@ -3,17 +3,10 @@
 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
-Library("interposers")
+Library("pthread_create_interposer")
 
-DEFINES["IMPL_MFBT"] = True
+NoVisibilityFlags()
 
 UNIFIED_SOURCES += [
-    "env_interposer.cpp",
+    "pthread_create_interposer.cpp",
 ]
-
-if CONFIG["MOZ_CRASHREPORTER"]:
-    UNIFIED_SOURCES += [
-        "pthread_create_interposer.cpp",
-    ]
-
-FINAL_LIBRARY = "mozglue"

toolkit/crashreporter/pthread_create_interposer/pthread_create_interposer.cpp

@@ -4,6 +4,7 @@
 
 #include <algorithm>
 
+#include <dlfcn.h>
 #include <pthread.h>
 #include <signal.h>
 #include <stdlib.h>
@@ -12,8 +13,6 @@
 #include "mozilla/Assertions.h"
 #include "mozilla/DebugOnly.h"
 
-#include "InterposerHelper.h"
-
 using mozilla::DebugOnly;
 
 struct SigAltStack {
@@ -84,12 +83,30 @@ void* set_alt_signal_stack_and_start(PthreadCreateParams* params) {
   return thread_rv;
 }
 
+using pthread_create_func_t = int (*)(pthread_t*, const pthread_attr_t*,
+                                      void* (*)(void*), void*);
+
 extern "C" {
 // This interposer replaces libpthread's pthread_create() so that we can
 // inject an alternate signal stack in every new thread.
-MFBT_API int pthread_create(pthread_t* thread, const pthread_attr_t* attr,
-                            void* (*start_routine)(void*), void* arg) {
-  static const auto real_pthread_create = GET_REAL_SYMBOL(pthread_create);
+__attribute__((visibility("default"))) int pthread_create(
+    pthread_t* thread, const pthread_attr_t* attr,
+    void* (*start_routine)(void*), void* arg) {
+  // static const pthread_create_func_t real_pthread_create =
+  static const pthread_create_func_t real_pthread_create =
+      (pthread_create_func_t)dlsym(RTLD_NEXT, "pthread_create");
+
+  if (real_pthread_create == nullptr) {
+    MOZ_CRASH(
+        "pthread_create() interposition failed but the interposer function is "
+        "still being called, this won't work!");
+  }
+
+  if (real_pthread_create == pthread_create) {
+    MOZ_CRASH(
+        "We could not obtain the real pthread_create(). Calling the symbol we "
+        "got would make us enter an infinte loop so stop here instead.");
+  }
 
   PthreadCreateParams* params =
       (PthreadCreateParams*)malloc(sizeof(PthreadCreateParams));