stack_util.cc | Explore in Territory

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "third_party/blink/renderer/platform/wtf/stack_util.h"

#include "build/build_config.h"
#include "base/notreached.h"
#include "third_party/blink/renderer/platform/wtf/threading.h"

#if BUILDFLAG(IS_WIN)
#include <windows.h>

#include <intrin.h>
#include <stddef.h>
#include <winnt.h>
#elif defined(__GLIBC__)
extern "C" void* __libc_stack_end;  // NOLINT
#endif

namespace WTF {

size_t GetUnderestimatedStackSize() { … }

void* GetStackStart() { … }

uintptr_t GetCurrentStackPosition() { … }

namespace internal {

uintptr_t g_main_thread_stack_start = …;
uintptr_t g_main_thread_underestimated_stack_size = …;

void InitializeMainThreadStackEstimate() { … }

#if BUILDFLAG(IS_WIN) && defined(COMPILER_MSVC)
size_t ThreadStackSize() {
  // Notice that we cannot use the TIB's StackLimit for the stack end, as i
  // tracks the end of the committed range. We're after the end of the reserved
  // stack area (most of which will be uncommitted, most times.)
  MEMORY_BASIC_INFORMATION stack_info;
  memset(&stack_info, 0, sizeof(MEMORY_BASIC_INFORMATION));
  size_t result_size =
      VirtualQuery(&stack_info, &stack_info, sizeof(MEMORY_BASIC_INFORMATION));
  DCHECK_GE(result_size, sizeof(MEMORY_BASIC_INFORMATION));
  uint8_t* stack_end = reinterpret_cast<uint8_t*>(stack_info.AllocationBase);

  uint8_t* stack_start = reinterpret_cast<uint8_t*>(WTF::GetStackStart());
  CHECK(stack_start);
  CHECK_GT(stack_start, stack_end);
  size_t thread_stack_size = static_cast<size_t>(stack_start - stack_end);
  // When the third last page of the reserved stack is accessed as a
  // guard page, the second last page will be committed (along with removing
  // the guard bit on the third last) _and_ a stack overflow exception
  // is raised.
  //
  // We have zero interest in running into stack overflow exceptions while
  // marking objects, so simply consider the last three pages + one above
  // as off-limits and adjust the reported stack size accordingly.
  //
  // http://blogs.msdn.com/b/satyem/archive/2012/08/13/thread-s-stack-memory-management.aspx
  // explains the details.
  CHECK_GT(thread_stack_size, 4u * 0x1000);
  thread_stack_size -= 4 * 0x1000;
  return thread_stack_size;
}
#endif

}  // namespace internal

}  // namespace WTF
chromium/third_party/blink/renderer/platform/wtf/stack_util.cc
