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BeefRT/gperftools/src/libc_override_osx.h

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+// Copyright (c) 2011, 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 <opensource@google.com>
+//
+// Used to override malloc routines on OS X systems.  We use the
+// malloc-zone functionality built into OS X to register our malloc
+// routine.
+//
+// 1) We used to use the normal 'override weak libc malloc/etc'
+// technique for OS X.  This is not optimal because mach does not
+// support the 'alias' attribute, so we had to have forwarding
+// functions.  It also does not work very well with OS X shared
+// libraries (dylibs) -- in general, the shared libs don't use
+// tcmalloc unless run with the DYLD_FORCE_FLAT_NAMESPACE envvar.
+//
+// 2) Another approach would be to use an interposition array:
+//      static const interpose_t interposers[] __attribute__((section("__DATA, __interpose"))) = {
+//        { (void *)tc_malloc, (void *)malloc },
+//        { (void *)tc_free, (void *)free },
+//      };
+// This requires the user to set the DYLD_INSERT_LIBRARIES envvar, so
+// is not much better.
+//
+// 3) Registering a new malloc zone avoids all these issues:
+//  http://www.opensource.apple.com/source/Libc/Libc-583/include/malloc/malloc.h
+//  http://www.opensource.apple.com/source/Libc/Libc-583/gen/malloc.c
+// If we make tcmalloc the default malloc zone (undocumented but
+// possible) then all new allocs use it, even those in shared
+// libraries.  Allocs done before tcmalloc was installed, or in libs
+// that aren't using tcmalloc for some reason, will correctly go
+// through the malloc-zone interface when free-ing, and will pick up
+// the libc free rather than tcmalloc free.  So it should "never"
+// cause a crash (famous last words).
+//
+// 4) The routines one must define for one's own malloc have changed
+// between OS X versions.  This requires some hoops on our part, but
+// is only really annoying when it comes to posix_memalign.  The right
+// behavior there depends on what OS version tcmalloc was compiled on,
+// but also what OS version the program is running on.  For now, we
+// punt and don't implement our own posix_memalign.  Apps that really
+// care can use tc_posix_memalign directly.
+
+#ifndef TCMALLOC_LIBC_OVERRIDE_OSX_INL_H_
+#define TCMALLOC_LIBC_OVERRIDE_OSX_INL_H_
+
+#include <config.h>
+#ifdef HAVE_FEATURES_H
+#include <features.h>
+#endif
+#include <gperftools/tcmalloc.h>
+
+#if !defined(__APPLE__)
+# error libc_override_glibc-osx.h is for OS X distributions only.
+#endif
+
+#include <AvailabilityMacros.h>
+#include <malloc/malloc.h>
+
+// from AvailabilityMacros.h
+#if defined(MAC_OS_X_VERSION_10_6) && \
+    MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
+extern "C" {
+  // This function is only available on 10.6 (and later) but the
+  // LibSystem headers do not use AvailabilityMacros.h to handle weak
+  // importing automatically.  This prototype is a copy of the one in
+  // <malloc/malloc.h> with the WEAK_IMPORT_ATTRBIUTE added.
+  extern malloc_zone_t *malloc_default_purgeable_zone(void)
+      WEAK_IMPORT_ATTRIBUTE;
+}
+#endif
+
+// We need to provide wrappers around all the libc functions.
+namespace {
+size_t mz_size(malloc_zone_t* zone, const void* ptr) {
+  if (MallocExtension::instance()->GetOwnership(ptr) != MallocExtension::kOwned)
+    return 0;  // malloc_zone semantics: return 0 if we don't own the memory
+
+  // TODO(csilvers): change this method to take a const void*, one day.
+  return MallocExtension::instance()->GetAllocatedSize(const_cast<void*>(ptr));
+}
+
+void* mz_malloc(malloc_zone_t* zone, size_t size) {
+  return tc_malloc(size);
+}
+
+void* mz_calloc(malloc_zone_t* zone, size_t num_items, size_t size) {
+  return tc_calloc(num_items, size);
+}
+
+void* mz_valloc(malloc_zone_t* zone, size_t size) {
+  return tc_valloc(size);
+}
+
+void mz_free(malloc_zone_t* zone, void* ptr) {
+  return tc_free(ptr);
+}
+
+void* mz_realloc(malloc_zone_t* zone, void* ptr, size_t size) {
+  return tc_realloc(ptr, size);
+}
+
+void* mz_memalign(malloc_zone_t* zone, size_t align, size_t size) {
+  return tc_memalign(align, size);
+}
+
+void mz_destroy(malloc_zone_t* zone) {
+  // A no-op -- we will not be destroyed!
+}
+
+// malloc_introspection callbacks.  I'm not clear on what all of these do.
+kern_return_t mi_enumerator(task_t task, void *,
+                            unsigned type_mask, vm_address_t zone_address,
+                            memory_reader_t reader,
+                            vm_range_recorder_t recorder) {
+  // Should enumerate all the pointers we have.  Seems like a lot of work.
+  return KERN_FAILURE;
+}
+
+size_t mi_good_size(malloc_zone_t *zone, size_t size) {
+  // I think it's always safe to return size, but we maybe could do better.
+  return size;
+}
+
+boolean_t mi_check(malloc_zone_t *zone) {
+  return MallocExtension::instance()->VerifyAllMemory();
+}
+
+void mi_print(malloc_zone_t *zone, boolean_t verbose) {
+  int bufsize = 8192;
+  if (verbose)
+    bufsize = 102400;   // I picked this size arbitrarily
+  char* buffer = new char[bufsize];
+  MallocExtension::instance()->GetStats(buffer, bufsize);
+  fprintf(stdout, "%s", buffer);
+  delete[] buffer;
+}
+
+void mi_log(malloc_zone_t *zone, void *address) {
+  // I don't think we support anything like this
+}
+
+void mi_force_lock(malloc_zone_t *zone) {
+  // Hopefully unneeded by us!
+}
+
+void mi_force_unlock(malloc_zone_t *zone) {
+  // Hopefully unneeded by us!
+}
+
+void mi_statistics(malloc_zone_t *zone, malloc_statistics_t *stats) {
+  // TODO(csilvers): figure out how to fill these out
+  stats->blocks_in_use = 0;
+  stats->size_in_use = 0;
+  stats->max_size_in_use = 0;
+  stats->size_allocated = 0;
+}
+
+boolean_t mi_zone_locked(malloc_zone_t *zone) {
+  return false;  // Hopefully unneeded by us!
+}
+
+}  // unnamed namespace
+
+// OS X doesn't have pvalloc, cfree, malloc_statc, etc, so we can just
+// define our own. :-)  OS X supplies posix_memalign in some versions
+// but not others, either strongly or weakly linked, in a way that's
+// difficult enough to code to correctly, that I just don't try to
+// support either memalign() or posix_memalign().  If you need them
+// and are willing to code to tcmalloc, you can use tc_posix_memalign().
+extern "C" {
+  void  cfree(void* p)                   { tc_cfree(p);               }
+  void* pvalloc(size_t s)                { return tc_pvalloc(s);      }
+  void malloc_stats(void)                { tc_malloc_stats();         }
+  int mallopt(int cmd, int v)            { return tc_mallopt(cmd, v); }
+  // No struct mallinfo on OS X, so don't define mallinfo().
+  // An alias for malloc_size(), which OS X defines.
+  size_t malloc_usable_size(void* p)     { return tc_malloc_size(p); }
+}  // extern "C"
+
+static void ReplaceSystemAlloc() {
+  static malloc_introspection_t tcmalloc_introspection;
+  memset(&tcmalloc_introspection, 0, sizeof(tcmalloc_introspection));
+
+  tcmalloc_introspection.enumerator = &mi_enumerator;
+  tcmalloc_introspection.good_size = &mi_good_size;
+  tcmalloc_introspection.check = &mi_check;
+  tcmalloc_introspection.print = &mi_print;
+  tcmalloc_introspection.log = &mi_log;
+  tcmalloc_introspection.force_lock = &mi_force_lock;
+  tcmalloc_introspection.force_unlock = &mi_force_unlock;
+
+  static malloc_zone_t tcmalloc_zone;
+  memset(&tcmalloc_zone, 0, sizeof(malloc_zone_t));
+
+  // Start with a version 4 zone which is used for OS X 10.4 and 10.5.
+  tcmalloc_zone.version = 4;
+  tcmalloc_zone.zone_name = "tcmalloc";
+  tcmalloc_zone.size = &mz_size;
+  tcmalloc_zone.malloc = &mz_malloc;
+  tcmalloc_zone.calloc = &mz_calloc;
+  tcmalloc_zone.valloc = &mz_valloc;
+  tcmalloc_zone.free = &mz_free;
+  tcmalloc_zone.realloc = &mz_realloc;
+  tcmalloc_zone.destroy = &mz_destroy;
+  tcmalloc_zone.batch_malloc = NULL;
+  tcmalloc_zone.batch_free = NULL;
+  tcmalloc_zone.introspect = &tcmalloc_introspection;
+
+  // from AvailabilityMacros.h
+#if defined(MAC_OS_X_VERSION_10_6) && \
+    MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
+  // Switch to version 6 on OSX 10.6 to support memalign.
+  tcmalloc_zone.version = 6;
+  tcmalloc_zone.free_definite_size = NULL;
+  tcmalloc_zone.memalign = &mz_memalign;
+  tcmalloc_introspection.zone_locked = &mi_zone_locked;
+
+  // Request the default purgable zone to force its creation. The
+  // current default zone is registered with the purgable zone for
+  // doing tiny and small allocs.  Sadly, it assumes that the default
+  // zone is the szone implementation from OS X and will crash if it
+  // isn't.  By creating the zone now, this will be true and changing
+  // the default zone won't cause a problem.  This only needs to
+  // happen when actually running on OS X 10.6 and higher (note the
+  // ifdef above only checks if we were *compiled* with 10.6 or
+  // higher; at runtime we have to check if this symbol is defined.)
+  if (malloc_default_purgeable_zone) {
+    malloc_default_purgeable_zone();
+  }
+#endif
+
+  // Register the tcmalloc zone. At this point, it will not be the
+  // default zone.
+  malloc_zone_register(&tcmalloc_zone);
+
+  // Unregister and reregister the default zone.  Unregistering swaps
+  // the specified zone with the last one registered which for the
+  // default zone makes the more recently registered zone the default
+  // zone.  The default zone is then re-registered to ensure that
+  // allocations made from it earlier will be handled correctly.
+  // Things are not guaranteed to work that way, but it's how they work now.
+  malloc_zone_t *default_zone = malloc_default_zone();
+  malloc_zone_unregister(default_zone);
+  malloc_zone_register(default_zone);
+}
+
+#endif  // TCMALLOC_LIBC_OVERRIDE_OSX_INL_H_