[MSan] Clear parameters shadow before invoking malloc/free hooks.

MSan runtime is not itself instrumented, so we need to explicitly
clear shadow for function arguments before calling user-provided
functions from runtime (e.g. we already do this for several
interceptors).

I'm still crafting a test case that would demonstrate this issue
reliably, and will commit it later today.

llvm-svn: 258339

1 files changed, 10 insertions, 4 deletions

diff --git a/compiler-rt/lib/msan/msan.h b/compiler-rt/lib/msan/msan.h
index 2079a592b7b..b41d097a5f0 100644
--- a/compiler-rt/lib/msan/msan.h
+++ b/compiler-rt/lib/msan/msan.h
@@ -309,9 +309,15 @@ void MsanTSDDtor(void *tsd);
 
 }  // namespace __msan
 
-#define MSAN_MALLOC_HOOK(ptr, size) \
-  if (&__sanitizer_malloc_hook) __sanitizer_malloc_hook(ptr, size)
-#define MSAN_FREE_HOOK(ptr) \
-  if (&__sanitizer_free_hook) __sanitizer_free_hook(ptr)
+#define MSAN_MALLOC_HOOK(ptr, size)     \
+  if (&__sanitizer_malloc_hook) {       \
+    UnpoisonParam(2);                   \
+    __sanitizer_malloc_hook(ptr, size); \
+  }
+#define MSAN_FREE_HOOK(ptr)     \
+  if (&__sanitizer_free_hook) { \
+    UnpoisonParam(1);           \
+    __sanitizer_free_hook(ptr); \
+  }
 
 #endif  // MSAN_H