Major changes to the Chrome allocator....

third_party/tcmalloc/port.cc

+/* Copyright (c) 2007, Google Inc.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ * 
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * ---
+ * Author: Craig Silverstein
+ */
+
+#ifndef _WIN32
+# error You should only be including windows/port.cc in a windows environment!
+#endif
+
+#include <config.h>
+#include <string.h>    // for strlen(), memset(), memcmp()
+#include <assert.h>
+#include <stdarg.h>    // for va_list, va_start, va_end
+#include <windows.h>
+#include "port.h"
+#include "base/logging.h"
+#include "base/spinlock.h"
+#include "system-alloc.h"
+
+// -----------------------------------------------------------------------
+// Basic libraries
+
+// These call the windows _vsnprintf, but always NUL-terminate.
+int safe_vsnprintf(char *str, size_t size, const char *format, va_list ap) {
+  if (size == 0)        // not even room for a \0?
+    return -1;          // not what C99 says to do, but what windows does
+  str[size-1] = '\0';
+  return _vsnprintf(str, size-1, format, ap);
+}
+
+#ifndef HAVE_SNPRINTF
+int snprintf(char *str, size_t size, const char *format, ...) {
+  va_list ap;
+  va_start(ap, format);
+  const int r = vsnprintf(str, size, format, ap);
+  va_end(ap);
+  return r;
+}
+#endif
+
+int getpagesize() {
+  static int pagesize = 0;
+  if (pagesize == 0) {
+    SYSTEM_INFO system_info;
+    GetSystemInfo(&system_info);
+    pagesize = system_info.dwPageSize;
+  }
+  return pagesize;
+}
+
+extern "C" PERFTOOLS_DLL_DECL void* __sbrk(ptrdiff_t increment) {
+  LOG(FATAL, "Windows doesn't implement sbrk!\n");
+  return NULL;
+}
+
+// -----------------------------------------------------------------------
+// Threads code
+
+bool CheckIfKernelSupportsTLS() {
+  // TODO(csilvers): return true (all win's since win95, at least, support this)
+  return false;
+}
+
+// Windows doesn't support pthread_key_create's destr_function, and in
+// fact it's a bit tricky to get code to run when a thread exits.  This
+// is cargo-cult magic from http://www.codeproject.com/threads/tls.asp.
+// This code is for VC++ 7.1 and later; VC++ 6.0 support is possible
+// but more busy-work -- see the webpage for how to do it.  If all
+// this fails, we could use DllMain instead.  The big problem with
+// DllMain is it doesn't run if this code is statically linked into a
+// binary (it also doesn't run if the thread is terminated via
+// TerminateThread, which if we're lucky this routine does).
+
+// This makes the linker create the TLS directory if it's not already
+// there (that is, even if __declspec(thead) is not used).
+#ifdef _MSC_VER
+#pragma comment(linker, "/INCLUDE:__tls_used")
+#endif
+
+// When destr_fn eventually runs, it's supposed to take as its
+// argument the tls-value associated with key that pthread_key_create
+// creates.  (Yeah, it sounds confusing but it's really not.)  We
+// store the destr_fn/key pair in this data structure.  Because we
+// store this in a single var, this implies we can only have one
+// destr_fn in a program!  That's enough in practice.  If asserts
+// trigger because we end up needing more, we'll have to turn this
+// into an array.
+struct DestrFnClosure {
+  void (*destr_fn)(void*);
+  pthread_key_t key_for_destr_fn_arg;
+};
+
+static DestrFnClosure destr_fn_info;   // initted to all NULL/0.
+
+static int on_process_term(void) {
+  if (destr_fn_info.destr_fn) {
+    void *ptr = TlsGetValue(destr_fn_info.key_for_destr_fn_arg);
+    // This shouldn't be necessary, but in Release mode, Windows
+    // sometimes trashes the pointer in the TLS slot, so we need to
+    // remove the pointer from the TLS slot before the thread dies.
+    TlsSetValue(destr_fn_info.key_for_destr_fn_arg, NULL);
+    if (ptr)  // pthread semantics say not to call if ptr is NULL
+      (*destr_fn_info.destr_fn)(ptr);
+  }
+  return 0;
+}
+
+static void NTAPI on_tls_callback(HINSTANCE h, DWORD dwReason, PVOID pv) {
+  if (dwReason == DLL_THREAD_DETACH) {   // thread is being destroyed!
+    on_process_term();
+  }
+}
+
+#ifdef _MSC_VER
+
+// This tells the linker to run these functions.
+#pragma data_seg(push, old_seg)
+#pragma data_seg(".CRT$XLB")
+static void (NTAPI *p_thread_callback)(HINSTANCE h, DWORD dwReason, PVOID pv)
+    = on_tls_callback;
+#pragma data_seg(".CRT$XTU")
+static int (*p_process_term)(void) = on_process_term;
+#pragma data_seg(pop, old_seg)
+
+#else  // #ifdef _MSC_VER  [probably msys/mingw]
+
+// We have to try the DllMain solution here, because we can't use the
+// msvc-specific pragmas.
+BOOL WINAPI DllMain(HINSTANCE h, DWORD dwReason, PVOID pv) {
+  if (dwReason == DLL_THREAD_DETACH)
+    on_tls_callback(h, dwReason, pv);
+  else if (dwReason == DLL_PROCESS_DETACH)
+    on_process_term();
+  return TRUE;
+}
+
+#endif  // #ifdef _MSC_VER
+
+pthread_key_t PthreadKeyCreate(void (*destr_fn)(void*)) {
+  // Semantics are: we create a new key, and then promise to call
+  // destr_fn with TlsGetValue(key) when the thread is destroyed
+  // (as long as TlsGetValue(key) is not NULL).
+  pthread_key_t key = TlsAlloc();
+  if (destr_fn) {   // register it
+    // If this assert fails, we'll need to support an array of destr_fn_infos
+    assert(destr_fn_info.destr_fn == NULL);
+    destr_fn_info.destr_fn = destr_fn;
+    destr_fn_info.key_for_destr_fn_arg = key;
+  }
+  return key;
+}
+
+
+// -----------------------------------------------------------------------
+// These functions replace system-alloc.cc
+
+static SpinLock alloc_lock(SpinLock::LINKER_INITIALIZED);
+
+// This is mostly like MmapSysAllocator::Alloc, except it does these weird
+// munmap's in the middle of the page, which is forbidden in windows.
+extern void* TCMalloc_SystemAlloc(size_t size, size_t *actual_size,
+                                  size_t alignment) {
+  // Safest is to make actual_size same as input-size.
+  if (actual_size) {
+    *actual_size = size;
+  }
+
+  SpinLockHolder sh(&alloc_lock);
+  // Align on the pagesize boundary
+  const int pagesize = getpagesize();
+  if (alignment < pagesize) alignment = pagesize;
+  size = ((size + alignment - 1) / alignment) * alignment;
+
+  // Ask for extra memory if alignment > pagesize
+  size_t extra = 0;
+  if (alignment > pagesize) {
+    extra = alignment - pagesize;
+  }
+
+  void* result = VirtualAlloc(0, size + extra,
+                              MEM_COMMIT|MEM_RESERVE, PAGE_READWRITE);
+  if (result == NULL)
+    return NULL;
+
+  // Adjust the return memory so it is aligned
+  uintptr_t ptr = reinterpret_cast<uintptr_t>(result);
+  size_t adjust = 0;
+  if ((ptr & (alignment - 1)) != 0) {
+    adjust = alignment - (ptr & (alignment - 1));
+  }
+
+  ptr += adjust;
+  return reinterpret_cast<void*>(ptr);
+}
+
+void TCMalloc_SystemRelease(void* start, size_t length) {
+  if (VirtualFree(start, length, MEM_DECOMMIT))
+    return;
+
+  // The decommit may fail if the memory region consists of allocations
+  // from more than one call to VirtualAlloc.  In this case, fall back to
+  // using VirtualQuery to retrieve the allocation boundaries and decommit
+  // them each individually.
+
+  char* ptr = static_cast<char*>(start);
+  char* end = ptr + length;
+  MEMORY_BASIC_INFORMATION info;
+  while (ptr < end) {
+    size_t resultSize = VirtualQuery(ptr, &info, sizeof(info));
+    assert(resultSize == sizeof(info));
+    size_t decommitSize = std::min<size_t>(info.RegionSize, end - ptr);
+    BOOL success = VirtualFree(ptr, decommitSize, MEM_DECOMMIT);
+    assert(success == TRUE);
+    ptr += decommitSize;
+  }
+}
+
+void TCMalloc_SystemCommit(void* start, size_t length)
+{
+  if (VirtualAlloc(start, length, MEM_COMMIT, PAGE_READWRITE) == start)
+    return;
+
+  // The commit may fail if the memory region consists of allocations
+  // from more than one call to VirtualAlloc.  In this case, fall back to
+  // using VirtualQuery to retrieve the allocation boundaries and commit them
+  // each individually.
+
+  char* ptr = static_cast<char*>(start);
+  char* end = ptr + length;
+  MEMORY_BASIC_INFORMATION info;
+  while (ptr < end) {
+    size_t resultSize = VirtualQuery(ptr, &info, sizeof(info));
+    assert(resultSize == sizeof(info));
+
+    size_t commitSize = std::min<size_t>(info.RegionSize, end - ptr);
+    void* newAddress = VirtualAlloc(ptr, commitSize, MEM_COMMIT,
+                                    PAGE_READWRITE);
+    assert(newAddress == ptr);
+    ptr += commitSize;
+  }
+}
+
+bool RegisterSystemAllocator(SysAllocator *allocator, int priority) {
+  return false;   // we don't allow registration on windows, right now
+}
+
+void DumpSystemAllocatorStats(TCMalloc_Printer* printer) {
+  // We don't dump stats on windows, right now
+}
+
+
+// -----------------------------------------------------------------------
+// These functions rework existing functions of the same name in the
+// Google codebase.
+
+// A replacement for HeapProfiler::CleanupOldProfiles.
+void DeleteMatchingFiles(const char* prefix, const char* full_glob) {
+  WIN32_FIND_DATAA found;  // that final A is for Ansi (as opposed to Unicode)
+  HANDLE hFind = FindFirstFileA(full_glob, &found);   // A is for Ansi
+  if (hFind != INVALID_HANDLE_VALUE) {
+    const int prefix_length = strlen(prefix);
+    do {
+      const char *fname = found.cFileName;
+      if ((strlen(fname) >= prefix_length) &&
+          (memcmp(fname, prefix, prefix_length) == 0)) {
+        RAW_VLOG(0, "Removing old heap profile %s\n", fname);
+        // TODO(csilvers): we really need to unlink dirname + fname
+        _unlink(fname);
+      }
+    } while (FindNextFileA(hFind, &found) != FALSE);  // A is for Ansi
+    FindClose(hFind);
+  }
+}