Method patchLibraries

src/mallocTracer.cpp:183–212

To avoid complexity in hooking and tracking reentrancy, a TLS-based approach is not used. Reentrant allocation calls would result in double-accounting. However, this does not impact the leak detector, as it correctly tracks memory as freed regardless of how many times recordMalloc is called with the same address.

// the leak detector, as it correctly tracks memory as freed regardless of how many times
// recordMalloc is called with the same address.
void MallocTracer::patchLibraries() {
    MutexLocker ml(_patch_lock);

    CodeCacheArray* native_libs = Profiler::instance()->nativeLibs();
    int native_lib_count = native_libs->count();

    while (_patched_libs < native_lib_count) {
        CodeCache* cc = (*native_libs)[_patched_libs++];

        UnloadProtection handle(cc);
        if (!handle.isValid()) {
            continue;
        }

        cc->patchImport(im_malloc, (void*)malloc_hook);
        cc->patchImport(im_realloc, (void*)realloc_hook);
        cc->patchImport(im_free, (void*)free_hook);
        cc->patchImport(im_aligned_alloc, (void*)aligned_alloc_hook);

        if (_nested_malloc) {
            // Use dummy hooks to prevent double-accounting. Dummy frames from AP are introduced
            // to preserve the frame link to the original caller (see #1226).
            cc->patchImport(im_calloc, (void*)calloc_hook_dummy);
            cc->patchImport(im_posix_memalign, (void*)posix_memalign_hook_dummy);
        } else {
            cc->patchImport(im_calloc, (void*)calloc_hook);
            cc->patchImport(im_posix_memalign, (void*)posix_memalign_hook);
        }
    }
}

void MallocTracer::recordMalloc(void* address, size_t size) {
    if (updateCounter(_allocated_bytes, size, _interval)) {