[asan] Avoid hooking memchr() on Windows64

There is not enough padding in front of memchr(), and, the first 6 bytes
contains a branch instruction. Basically the current interception will
not work on memchr().

It was disabled before, but was missing the part to disable it for
INTERCEPT_LIBRARY_FUNCTION.

Patch by Wei Wang

Differential Revision: https://reviews.llvm.org/D22371


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@275494 91177308-0d34-0410-b5e6-96231b3b80d8

Author: bergeret

lib/asan/asan_win_dll_thunk.cc

@@ -21,6 +21,7 @@
 #ifdef ASAN_DLL_THUNK
 #include "asan_init_version.h"
 #include "interception/interception.h"
+#include "sanitizer_common/sanitizer_platform_interceptors.h"
 
 // ---------- Function interception helper functions and macros ----------- {{{1
 extern "C" {
@@ -390,7 +391,9 @@ INTERCEPTOR(int, _except_handler4, void *a, void *b, void *c, void *d) {
 
 INTERCEPT_LIBRARY_FUNCTION(frexp);
 INTERCEPT_LIBRARY_FUNCTION(longjmp);
+#if SANITIZER_INTERCEPT_MEMCHR
 INTERCEPT_LIBRARY_FUNCTION(memchr);
+#endif
 INTERCEPT_LIBRARY_FUNCTION(memcmp);
 INTERCEPT_LIBRARY_FUNCTION(memcpy);
 INTERCEPT_LIBRARY_FUNCTION(memmove);

lib/sanitizer_common/sanitizer_platform_interceptors.h

@@ -83,10 +83,9 @@
 #define SANITIZER_INTERCEPT_MEMMOVE 1
 #define SANITIZER_INTERCEPT_MEMCPY 1
 #define SANITIZER_INTERCEPT_MEMCMP 1
-// TODO(wwchrome): Re-enable intercepting memchr() when ready.
 // The function memchr() contains a jump in the first 6 bytes
 // that is problematic to intercept correctly on Win64.
-// Disable memchr() interception for Win64 temporarily.
+// Disable memchr() interception for Win64.
 #if SANITIZER_WINDOWS64
 #define SANITIZER_INTERCEPT_MEMCHR 0
 #else