allocator/Windows: delete the old non-unified allocator-shim

base/allocator/allocator_shim_win.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.
-
-// The allocator shim is only enabled in Release Static builds.
-// This #if is needed as gyp can't have different compile
-// targets between Debug and Release.
-// TODO(wfh): Remove this once gyp is dead.
-// TODO(siggi): Remove this file once the generic shim sticks.
-#if defined(ALLOCATOR_SHIM)
-
-#include <limits.h>
-#include <malloc.h>
-#include <new.h>
-#include <windows.h>
-#include <stddef.h>
-
-#include "base/allocator/allocator_shim_win.h"
-#include "base/allocator/winheap_stubs_win.h"
-
-// This shim make it possible to perform additional checks on allocations
-// before passing them to the Heap functions.
-
-// Override heap functions to perform additional checks:
-// 1. Enforcing the maximum size that can be allocated to 2Gb.
-// 2. Calling new_handler if malloc fails
-
-// See definitions of original functions in ucrt\corecrt_malloc.h in SDK
-// include directory.
-
-namespace {
-
-int new_mode = 0;
-
-}  // namespace
-
-extern "C" {
-
-// Symbol to allow weak linkage to WinHeapMalloc from allocator_impl_win.cc.
-void* (*malloc_unchecked)(size_t) = &base::allocator::WinHeapMalloc;
-
-// This function 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.
-// Returns the previous mode.
-//
-// Replaces _set_new_mode in ucrt\heap\new_mode.cpp
-int _set_new_mode(int flag) {
-  // The MS CRT calls this function early on in startup, so this serves as a low
-  // overhead proof that the allocator shim is in place for this process.
-  base::allocator::g_is_win_shim_layer_initialized = true;
-  int old_mode = new_mode;
-  new_mode = flag;
-
-  return old_mode;
-}
-
-// Replaces _query_new_mode in ucrt\heap\new_mode.cpp
-int _query_new_mode() {
-  return new_mode;
-}
-
-// Replaces malloc in ucrt\heap\malloc.cpp
-__declspec(restrict) void* malloc(size_t size) {
-  void* ptr;
-  for (;;) {
-    ptr = base::allocator::WinHeapMalloc(size);
-    if (ptr)
-      return ptr;
-
-    if (!new_mode || base::allocator::WinCallNewHandler(size))
-      break;
-  }
-  return ptr;
-}
-
-// Replaces free in ucrt\heap\free.cpp
-void free(void* p) {
-  base::allocator::WinHeapFree(p);
-  return;
-}
-
-// Replaces realloc in ucrt\heap\realloc.cpp
-__declspec(restrict) 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 (;;) {
-    new_ptr = base::allocator::WinHeapRealloc(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 || !base::allocator::WinCallNewHandler(size))
-      break;
-  }
-  return new_ptr;
-}
-
-// Replaces calloc in ucrt\heap\calloc.cpp
-__declspec(restrict) void* calloc(size_t n, size_t elem_size) {
-  // Overflow check.
-  const size_t size = n * elem_size;
-  if (elem_size != 0 && size / elem_size != n)
-    return nullptr;
-
-  void* result = malloc(size);
-  if (result) {
-    memset(result, 0, size);
-  }
-  return result;
-}
-
-}  // extern C
-
-#endif  // defined(ALLOCATOR_SHIM)