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//
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//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// 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_