[compiler-rt] Fix memmove/memcpy overlap detection on windows

Summary:
The memcpy and memmove functions are the same on windows.
The overlap detection logic is incorrect.

printf-1 test:
```
stdin>:2:114: note: possible intended match here
==877412==ERROR: AddressSanitizer: memcpy-param-overlap: memory ranges [0x0000002bf2a8,0x0000002bf2ad) and [0x0000002bf2a9, 0x0000002bf2ae) overlap
```                                                                                                                 ^

Reviewers: rnk

Subscribers: llvm-commits, wang0109, kubabrecka, chrisha

Differential Revision: https://reviews.llvm.org/D22610

llvm-svn: 276299

compiler-rt/lib/asan/asan_interceptors.cc

@@ -725,11 +725,12 @@ void InitializeAsanInterceptors() {
   InitializeCommonInterceptors();
 
   // Intercept mem* functions.
-  ASAN_INTERCEPT_FUNC(memcpy);
   ASAN_INTERCEPT_FUNC(memset);
+  ASAN_INTERCEPT_FUNC(memmove);
   if (PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE) {
-    // In asan, REAL(memmove) is not used, but it is used in msan.
-    ASAN_INTERCEPT_FUNC(memmove);
+    ASAN_INTERCEPT_FUNC(memcpy);
+  } else {
+    REAL(memcpy) = REAL(memmove);
   }
   CHECK(REAL(memcpy));
 

compiler-rt/lib/asan/tests/asan_str_test.cc

@@ -456,12 +456,14 @@ TEST(AddressSanitizer, StrArgsOverlapTest) {
 // memmove().
 #if !defined(__APPLE__) || !defined(MAC_OS_X_VERSION_10_7) || \
     (MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7)
+#if PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE
   // Check "memcpy". Use Ident() to avoid inlining.
   memset(str, 'z', size);
   Ident(memcpy)(str + 1, str + 11, 10);
   Ident(memcpy)(str, str, 0);
   EXPECT_DEATH(Ident(memcpy)(str, str + 14, 15), OverlapErrorMessage("memcpy"));
   EXPECT_DEATH(Ident(memcpy)(str + 14, str, 15), OverlapErrorMessage("memcpy"));
+#endif
 #endif
 
   // We do not treat memcpy with to==from as a bug.