[PATCH] D15287: [tsan] Fix memcmp interceptor to correctly use COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED

[Kuba Brecka via llvm-commits]

kubabrecka created this revision.
kubabrecka added reviewers: dvyukov, samsonov, glider, kcc.
kubabrecka added subscribers: llvm-commits, zaks.anna.

The `memcmp` interceptor checks COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED only after it calls COMMON_INTERCEPTOR_ENTER, which causes an early process launch crash when running TSan in iOS simulator.  Let's fix this by checking COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED as the very first thing in the interceptor.

http://reviews.llvm.org/D15287

Files:
  lib/sanitizer_common/sanitizer_common_interceptors.inc

Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -403,10 +403,10 @@
                               const void *s1, const void *s2, uptr n)
 
 INTERCEPTOR(int, memcmp, const void *a1, const void *a2, uptr size) {
-  void *ctx;
-  COMMON_INTERCEPTOR_ENTER(ctx, memcmp, a1, a2, size);
   if (COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED)
     return internal_memcmp(a1, a2, size);
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, memcmp, a1, a2, size);
   CALL_WEAK_INTERCEPTOR_HOOK(__sanitizer_weak_hook_memcmp, GET_CALLER_PC(), a1,
                              a2, size);
   if (common_flags()->intercept_memcmp) {


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