[PATCH] D20402: Work around crashes in `__sanitizer_malloc_hook()` under Mac OSX.

[Dan Liew via llvm-commits]

delcypher retitled this revision from "Try to fix libFuzzer running on Mac OSX" to "Work around crashes in `__sanitizer_malloc_hook()` under Mac OSX.".
delcypher updated the summary for this revision.
delcypher updated this revision to Diff 57835.

http://reviews.llvm.org/D20402

Files:
  lib/Fuzzer/FuzzerInternal.h
  lib/Fuzzer/FuzzerLoop.cpp

Index: lib/Fuzzer/FuzzerLoop.cpp
===================================================================
--- lib/Fuzzer/FuzzerLoop.cpp
+++ lib/Fuzzer/FuzzerLoop.cpp
@@ -437,9 +437,21 @@
 
 static thread_local MallocFreeTracer AllocTracer;
 
+// FIXME: The hooks only count on Linux because
+// on Mac OSX calls to malloc are intercepted before
+// thread local storage is initialised leading to
+// crashes when accessing ``AllocTracer``.
 extern "C" {
-void __sanitizer_malloc_hook(void *ptr, size_t size) { AllocTracer.Mallocs++; }
-void __sanitizer_free_hook(void *ptr) { AllocTracer.Frees++; }
+void __sanitizer_malloc_hook(void *ptr, size_t size) {
+  if (LIBFUZZER_LINUX) {
+    AllocTracer.Mallocs++;
+  }
+}
+void __sanitizer_free_hook(void *ptr) {
+  if (LIBFUZZER_LINUX) {
+    AllocTracer.Frees++;
+  }
+}
 }  // extern "C"
 
 void Fuzzer::ExecuteCallback(const uint8_t *Data, size_t Size) {
Index: lib/Fuzzer/FuzzerInternal.h
===================================================================
--- lib/Fuzzer/FuzzerInternal.h
+++ lib/Fuzzer/FuzzerInternal.h
@@ -27,6 +27,17 @@
 #include "FuzzerInterface.h"
 #include "FuzzerTracePC.h"
 
+// Platform detection.
+#ifdef __linux__
+#define LIBFUZZER_LINUX 1
+#define LIBFUZZER_APPLE 0
+#elif __APPLE__
+#define LIBFUZZER_LINUX 0
+#define LIBFUZZER_APPLE 1
+#else
+#error "Support for your platform has not been implemented"
+#endif
+
 namespace fuzzer {
 
 typedef int (*UserCallback)(const uint8_t *Data, size_t Size);


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