[Tracing] Add allocation register for heap profiling

base/trace_event/memory_profiler_allocation_register_win.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.

[Primiano Tucci (use gerrit), 2015/10/05 14:11:06]

I'd probably defer introducing this file to once you have a working
implementation. You don't want to be debugging on Windows (already), so let's
just explicitly not support windows yet.

[Ruud van Asseldonk, 2015/10/06 09:26:45]

I ran it on the Windows trybots to debug and it works. What is the alternative,
#ifdefing all the code to only run on Linux? (I do have to change _linux to
_posix and get it to build on the other platforms as well.)

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/trace_event/memory_profiler_allocation_register.h"
+
+#include <windows.h>
+
+#include "base/logging.h"
+
+namespace base {
+namespace trace_event {
+
+size_t GetSystemPageSize() {
+  SYSTEM_INFO system_info;
+  GetSystemInfo(&system_info);
+  return system_info.dwPageSize;
+}
+
+void* AllocateVirtualMemory(size_t min_size, VirtualMemoryGuard guard) {
+  size_t size = RoundUpToPageSize(min_size);
+  size_t map_size = size;
+
+  if (guard == VirtualMemoryGuard::kGuardPageAfter)
+    map_size += GetSystemPageSize();
+
+  // Reserve the address space. This does not make the memory usable yet.
+  void* addr = VirtualAlloc(nullptr, map_size, MEM_RESERVE, PAGE_NOACCESS);
+
+  PCHECK(addr != nullptr);
+
+  // Commit the non-guard pages as read-write memory.
+  void* result = VirtualAlloc(addr, size, MEM_COMMIT, PAGE_READWRITE);
+
+  PCHECK(result != nullptr);
+
+  // If there is a guard page after, mark the last page of the allocated
+  // address space as such. (NB: The |PAGE_GUARD| flag is not the flag to use
+  // here, that flag can be used to detect and intercept access to a certain
+  // memory region. Accessing a |PAGE_NOACCESS| page will raise a general
+  // protection fault.) The read/write accessible space is still at least
+  // |min_size| bytes.
+  if (guard == VirtualMemoryGuard::kGuardPageAfter) {
+    void* guard_addr = static_cast<void*>(static_cast<uint8_t*>(addr) + size);
+    size_t guard_size = map_size - size;
+    result = VirtualAlloc(guard_addr, guard_size, MEM_COMMIT, PAGE_NOACCESS);
+    PCHECK(result != nullptr);
+  }
+
+  return addr;
+}
+
+void FreeVirtualMemory(void* address,
+                       size_t allocated_min_size,
+                       VirtualMemoryGuard allocated_guard) {
+  // For |VirtualFree|, the size passed with |MEM_RELEASE| mut be 0. Windows
+  // automatically frees the entire region that was reserved by the
+  // |VirtualAlloc| with flag |MEM_RESERVE|.
+  VirtualFree(address, 0, MEM_RELEASE);
+}
+
+}  // namespace trace_event
+}  // namespace base