[WinASan] Fix hotpatching new Win 10 build 1703 x64 strnlen prologue

The first instruction of the new ucrtbase!strnlen implementation loads a
global, presumably to dispatch between SSE and non-SSE optimized strnlen
implementations.

Fixes PR32895 and probably
https://github.com/google/sanitizers/issues/818

llvm-svn: 305581

1 files changed, 11 insertions, 0 deletions

diff --git a/compiler-rt/lib/interception/tests/interception_win_test.cc b/compiler-rt/lib/interception/tests/interception_win_test.cc
index a705768d6d5..37ef994f83d 100644
--- a/compiler-rt/lib/interception/tests/interception_win_test.cc
+++ b/compiler-rt/lib/interception/tests/interception_win_test.cc
@@ -170,6 +170,13 @@ const u8 kPatchableCode5[] = {
     0x54,                                      // push    esp
 };
 
+#if SANITIZER_WINDOWS64
+u8 kLoadGlobalCode[] = {
+  0x8B, 0x05, 0x00, 0x00, 0x00, 0x00, // mov    eax [rip + global]
+  0xC3,                               // ret
+};
+#endif
+
 const u8 kUnpatchableCode1[] = {
     0xC3,                           // ret
 };
@@ -502,6 +509,10 @@ TEST(Interception, PatchableFunction) {
   EXPECT_TRUE(TestFunctionPatching(kPatchableCode4, override));
   EXPECT_TRUE(TestFunctionPatching(kPatchableCode5, override));
 
+#if SANITIZER_WINDOWS64
+  EXPECT_TRUE(TestFunctionPatching(kLoadGlobalCode, override));
+#endif
+
   EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode1, override));
   EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode2, override));
   EXPECT_FALSE(TestFunctionPatching(kUnpatchableCode3, override));