From 70a35422b5509a456584b132ad8ce4466af323ea Mon Sep 17 00:00:00 2001
From: Francis Ricci <francisjricci@gmail.com>
Date: Thu, 15 Jun 2017 11:04:33 -0400
Subject: [PATCH] Ignore current_instance heap allocation when leak sanitizer
 is enabled

Without this patch, any user program that enables LeakSanitizer will
see a leak from tcmalloc. Add a weak hook to __lsan_ignore_object,
so that if LeakSanitizer is enabled, the allocation can be ignored.
---
 Makefile.am             |  3 +++
 src/malloc_extension.cc | 13 +++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/Makefile.am b/Makefile.am
index 0aeb77d..ab9041c 100755
--- a/Makefile.am
+++ b/Makefile.am
@@ -79,6 +79,9 @@ TCMALLOC_FLAGS =
 if MINGW
 TCMALLOC_FLAGS += -Wl,-u__tcmalloc
 endif MINGW
+if OSX
+AM_LDFLAGS += -Wl,-U,___lsan_ignore_object
+endif OSX
 
 # If we have objcopy, make malloc/free/etc weak symbols.  That way folks
 # can override our malloc if they want to (they can still use tc_malloc).
diff --git a/src/malloc_extension.cc b/src/malloc_extension.cc
index 6e69552..5c98c0e 100644
--- a/src/malloc_extension.cc
+++ b/src/malloc_extension.cc
@@ -205,6 +205,16 @@ void MallocExtension::MarkThreadTemporarilyIdle() {
 
 static MallocExtension* current_instance;
 
+#if (!defined(_WIN32) && !defined(__MINGW32__))
+// Provide a weak hook for __lsan_ignore_object, so that
+// if leak sanitizer is enabled, we can ignore the current_instance
+// heap allocation.
+extern "C" void __attribute__((weak)) __lsan_ignore_object(const void *);
+#else
+// Weak hooks aren't supported on windows, but neither is leak sanitizer.
+void (*__lsan_ignore_object)(const void *) = nullptr;
+#endif
+
 static void InitModule() {
   if (current_instance != NULL) {
     return;
@@ -213,6 +223,9 @@ static void InitModule() {
 #ifndef NO_HEAP_CHECK
   HeapLeakChecker::IgnoreObject(current_instance);
 #endif
+  if (__lsan_ignore_object) {
+    __lsan_ignore_object(current_instance);
+  }
 }
 
 REGISTER_MODULE_INITIALIZER(malloc_extension_init, InitModule())