Remove tcmalloc when not being used. Restore shim on Windows.

base/allocator/allocator_shim.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "base/allocator/allocator_shim.h"
+#include <new.h>
 
-#include <config.h>
 #include "base/allocator/allocator_extension_thunks.h"
 #include "base/profiler/alternate_timer.h"
 #include "base/sysinfo.h"
 
-// This shim make it possible to use different allocators via an environment
-// variable set before running the program. This may reduce the
-// amount of inlining that we get with malloc/free/etc.
-
-// TODO(mbelshe): Ensure that all calls to tcmalloc have the proper call depth
-// from the "user code" so that debugging tools (HeapChecker) can work.
+// This shim make it possible to perform additional checks on allocations
+// before passing them to the Heap functions.
 
 // new_mode behaves similarly to MSVC's _set_new_mode.
 // If flag is 0 (default), calls to malloc will behave normally.
 // If flag is 1, calls to malloc will behave like calls to new,
 // and the std_new_handler will be invoked on failure.
 // Can be set by calling _set_new_mode().
 static int new_mode = 0;

[cpu_(ooo_6.6-7.5), 2015/01/07 17:28:42]

I don't see anybody setting new_mode

[Will Harris, 2015/01/07 17:32:47]

new_mode global is removed from libcmt in prep_libc.py

https://code.google.com/p/chromium/codesearch#chromium/src/base/allocator/pre...

and this new_mode static replaces it by link-fu, so it's actually accessed from
the CRT _set_new_mode function, called from your CL.

 
-typedef enum {
-  TCMALLOC,    // TCMalloc is the default allocator.
-  WINHEAP,     // Windows Heap (standard Windows allocator).
-  WINLFH,      // Windows LFH Heap.
-} Allocator;
-
-// This is the default allocator. This value can be changed at startup by
-// specifying environment variables shown below it.
-// See SetupSubprocessAllocator() to specify a default secondary (subprocess)
-// allocator.
-// TODO(jar): Switch to using TCMALLOC for the renderer as well.
-#if defined(SYZYASAN)
-// SyzyASan requires the use of "WINHEAP".
-static Allocator allocator = WINHEAP;
-#else
-static Allocator allocator = TCMALLOC;
-#endif
-// The names of the environment variables that can optionally control the
-// selection of the allocator.  The primary may be used to control overall
-// allocator selection, and the secondary can be used to specify an allocator
-// to use in sub-processes.
-static const char primary_name[] = "CHROME_ALLOCATOR";
-static const char secondary_name[] = "CHROME_ALLOCATOR_2";
-
-// We include tcmalloc and the win_allocator to get as much inlining as
-// possible.
-#include "debugallocation_shim.cc"
+// We include the win_allocator to get as much inlining as possible.
 #include "win_allocator.cc"
 
 // Call the new handler, if one has been set.
 // Returns true on successfully calling the handler, false otherwise.
-inline bool call_new_handler(bool nothrow) {
-  // Get the current new handler.  NB: this function is not
-  // thread-safe.  We make a feeble stab at making it so here, but
-  // this lock only protects against tcmalloc interfering with
-  // itself, not with other libraries calling set_new_handler.
-  std::new_handler nh;
-  {
-    SpinLockHolder h(&set_new_handler_lock);
-    nh = std::set_new_handler(0);
-    (void) std::set_new_handler(nh);
-  }
+inline bool call_new_handler(bool nothrow, size_t size) {
+  // Get the current new handler.
+  _PNH nh = _query_new_handler();
 #if (defined(__GNUC__) && !defined(__EXCEPTIONS)) || \
     (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS)
   if (!nh)
     return false;
   // Since exceptions are disabled, we don't really know if new_handler
   // failed.  Assume it will abort if it fails.
-  (*nh)();
-  return false;  // break out of the retry loop.
+  return nh(size);
 #else
   // If no new_handler is established, the allocation failed.
   if (!nh) {
     if (nothrow)
       return false;
     throw std::bad_alloc();
   }
   // Otherwise, try the new_handler.  If it returns, retry the
   // allocation.  If it throws std::bad_alloc, fail the allocation.
   // if it throws something else, don't interfere.
   try {
-    (*nh)();
+    return nh(size);
   } catch (const std::bad_alloc&) {
     if (!nothrow)
       throw;
     return true;
   }
 #endif  // (defined(__GNUC__) && !defined(__EXCEPTIONS)) || (defined(_HAS_EXCEPTIONS) && !_HAS_EXCEPTIONS)
   return false;
 }
 
 extern "C" {
 void* malloc(size_t size) {
   void* ptr;
   for (;;) {
-    switch (allocator) {
-      case WINHEAP:
-      case WINLFH:
-        ptr = win_heap_malloc(size);
-        break;
-      case TCMALLOC:
-      default:
-        ptr = do_malloc(size);
-        break;
-    }
+    ptr = win_heap_malloc(size);
     if (ptr)
       return ptr;
 
-    if (!new_mode || !call_new_handler(true))
+    if (!new_mode || !call_new_handler(true, size))
       break;
   }
   return ptr;
 }
 
 void free(void* p) {
-  switch (allocator) {
-    case WINHEAP:
-    case WINLFH:
-      win_heap_free(p);
-      return;
-    case TCMALLOC:
-      do_free(p);
-      return;
-  }
+  win_heap_free(p);
+  return;
 }
 
 void* realloc(void* ptr, size_t size) {
   // Webkit is brittle for allocators that return NULL for malloc(0).  The
   // realloc(0, 0) code path does not guarantee a non-NULL return, so be sure
   // to call malloc for this case.
   if (!ptr)
     return malloc(size);
 
   void* new_ptr;
   for (;;) {
-    switch (allocator) {
-      case WINHEAP:
-      case WINLFH:
-        new_ptr = win_heap_realloc(ptr, size);
-        break;
-      case TCMALLOC:
-      default:
-        new_ptr = do_realloc(ptr, size);
-        break;
-    }
+    new_ptr = win_heap_realloc(ptr, size);
 
     // Subtle warning:  NULL return does not alwas indicate out-of-memory.  If
     // the requested new size is zero, realloc should free the ptr and return
     // NULL.
     if (new_ptr || !size)
       return new_ptr;
-    if (!new_mode || !call_new_handler(true))
+    if (!new_mode || !call_new_handler(true, size))
       break;
   }
   return new_ptr;
 }
 
 // TODO(mbelshe): Implement this for other allocators.
 void malloc_stats(void) {
-  switch (allocator) {
-    case WINHEAP:
-    case WINLFH:
-      // No stats.
-      return;
-    case TCMALLOC:
-      tc_malloc_stats();
-      return;
-  }
+  // No stats.
+  return;
 }
 
 #ifdef WIN32
 
 extern "C" size_t _msize(void* p) {
-  switch (allocator) {
-    case WINHEAP:
-    case WINLFH:
-      return win_heap_msize(p);
-  }
-
-  // TCMALLOC
-  return MallocExtension::instance()->GetAllocatedSize(p);
+  return win_heap_msize(p);
 }
 
 // This is included to resolve references from libcmt.
 extern "C" intptr_t _get_heap_handle() {
   return 0;
 }
 
 static bool get_allocator_waste_size_thunk(size_t* size) {
-  switch (allocator) {
-    case WINHEAP:
-    case WINLFH:
-      // TODO(alexeif): Implement for allocators other than tcmalloc.
-      return false;
-  }
-  size_t heap_size, allocated_bytes, unmapped_bytes;
-  MallocExtension* ext = MallocExtension::instance();
-  if (ext->GetNumericProperty("generic.heap_size", &heap_size) &&
-      ext->GetNumericProperty("generic.current_allocated_bytes",
-                              &allocated_bytes) &&
-      ext->GetNumericProperty("tcmalloc.pageheap_unmapped_bytes",
-                              &unmapped_bytes)) {
-    *size = heap_size - allocated_bytes - unmapped_bytes;
-    return true;
-  }
+  // TODO(alexeif): Implement for allocators other than tcmalloc.
   return false;
 }
 
-static void get_stats_thunk(char* buffer, int buffer_length) {
-  MallocExtension::instance()->GetStats(buffer, buffer_length);
-}
-
-static void release_free_memory_thunk() {
-  MallocExtension::instance()->ReleaseFreeMemory();
-}
-
 // The CRT heap initialization stub.
 extern "C" int _heap_init() {
-// Don't use the environment variable if SYZYASAN is defined, as the
-// implementation requires Winheap to be the allocator.
-#if !defined(SYZYASAN)
-  const char* environment_value = GetenvBeforeMain(primary_name);
-  if (environment_value) {
-    if (!stricmp(environment_value, "winheap"))
-      allocator = WINHEAP;
-    else if (!stricmp(environment_value, "winlfh"))
-      allocator = WINLFH;
-    else if (!stricmp(environment_value, "tcmalloc"))
-      allocator = TCMALLOC;
-  }
-#endif
-
-  switch (allocator) {
-    case WINHEAP:
-      return win_heap_init(false) ? 1 : 0;
-    case WINLFH:
-      return win_heap_init(true) ? 1 : 0;
-    case TCMALLOC:
-    default:
-      // fall through
-      break;
-  }
-
-  // Initializing tcmalloc.
-  // We intentionally leak this object.  It lasts for the process
-  // lifetime.  Trying to teardown at _heap_term() is so late that
-  // you can't do anything useful anyway.
-  new TCMallocGuard();
-
-  // Provide optional hook for monitoring allocation quantities on a per-thread
-  // basis.  Only set the hook if the environment indicates this needs to be
-  // enabled.
-  const char* profiling =
-      GetenvBeforeMain(tracked_objects::kAlternateProfilerTime);
-  if (profiling && *profiling == '1') {
-    tracked_objects::SetAlternateTimeSource(
-        tcmalloc::ThreadCache::GetBytesAllocatedOnCurrentThread,
-        tracked_objects::TIME_SOURCE_TYPE_TCMALLOC);
-  }
-
-  base::allocator::thunks::SetGetAllocatorWasteSizeFunction(
-      get_allocator_waste_size_thunk);
-  base::allocator::thunks::SetGetStatsFunction(get_stats_thunk);
-  base::allocator::thunks::SetReleaseFreeMemoryFunction(
-      release_free_memory_thunk);
-
-  return 1;
+  return win_heap_init() ? 1 : 0;
 }
 
 // The CRT heap cleanup stub.
 extern "C" void _heap_term() {}
 
 // We set this to 1 because part of the CRT uses a check of _crtheap != 0
 // to test whether the CRT has been initialized.  Once we've ripped out
 // the allocators from libcmt, we need to provide this definition so that
 // the rest of the CRT is still usable.
 extern "C" void* _crtheap = reinterpret_cast<void*>(1);
 
 // Provide support for aligned memory through Windows only _aligned_malloc().
 void* _aligned_malloc(size_t size, size_t alignment) {
   // _aligned_malloc guarantees parameter validation, so do so here.  These
   // checks are somewhat stricter than _aligned_malloc() since we're effectively
   // using memalign() under the hood.
   DCHECK_GT(size, 0U);
   DCHECK_EQ(alignment & (alignment - 1), 0U);
   DCHECK_EQ(alignment % sizeof(void*), 0U);
 
   void* ptr;
   for (;;) {
-    switch (allocator) {
-      case WINHEAP:
-      case WINLFH:
-        ptr = win_heap_memalign(alignment, size);
-        break;
-      case TCMALLOC:
-      default:
-        ptr = tc_memalign(alignment, size);
-        break;
-    }
+    ptr = win_heap_memalign(alignment, size);
 
     if (ptr) {
       // Sanity check alignment.
       DCHECK_EQ(reinterpret_cast<uintptr_t>(ptr) & (alignment - 1), 0U);
       return ptr;
     }
 
-    if (!new_mode || !call_new_handler(true))
+    if (!new_mode || !call_new_handler(true, size))
       break;
   }
   return ptr;
 }
 
 void _aligned_free(void* p) {
-  // TCMalloc returns pointers from memalign() that are safe to use with free().
   // Pointers allocated with win_heap_memalign() MUST be freed via
   // win_heap_memalign_free() since the aligned pointer is not the real one.
-  switch (allocator) {
-    case WINHEAP:
-    case WINLFH:
-      win_heap_memalign_free(p);
-      return;
-    case TCMALLOC:
-      do_free(p);
-  }
+  win_heap_memalign_free(p);
 }
 
 #endif  // WIN32
 
 #include "generic_allocators.cc"
 
 }  // extern C
-
-namespace base {
-namespace allocator {
-
-void SetupSubprocessAllocator() {
-  size_t primary_length = 0;
-  getenv_s(&primary_length, NULL, 0, primary_name);
-
-  size_t secondary_length = 0;
-  char buffer[20];
-  getenv_s(&secondary_length, buffer, sizeof(buffer), secondary_name);
-  DCHECK_GT(sizeof(buffer), secondary_length);
-  buffer[sizeof(buffer) - 1] = '\0';
-
-  if (secondary_length || !primary_length) {
-// Don't use the environment variable if SYZYASAN is defined, as the
-// implementation require Winheap to be the allocator.
-#if !defined(SYZYASAN)
-    const char* secondary_value = secondary_length ? buffer : "TCMALLOC";
-    // Force renderer (or other subprocesses) to use secondary_value.
-#else
-    const char* secondary_value = "WINHEAP";
-#endif
-    int ret_val = _putenv_s(primary_name, secondary_value);
-    DCHECK_EQ(0, ret_val);
-  }
-}
-
-void* TCMallocDoMallocForTest(size_t size) {
-  return do_malloc(size);
-}
-
-void TCMallocDoFreeForTest(void* ptr) {
-  do_free(ptr);
-}
-
-size_t ExcludeSpaceForMarkForTest(size_t size) {
-  return ExcludeSpaceForMark(size);
-}
-
-}  // namespace allocator.
-}  // namespace base.