[compiler-rt] [compiler-rt] Intercept MinGW x86-64 import thunks (PR #222710)

[Thurston Dang via llvm-commits]

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@@ -1122,6 +1122,33 @@ bool OverrideFunctionWithDetour(
 
 bool OverrideFunctionWithRedirectJump(
     uptr old_func, uptr new_func, uptr *orig_old_func) {
+#  if SANITIZER_WINDOWS64 && defined(__GNUC__) && !defined(__clang__)
+  u8* old_u8 = (u8*)old_func;
+
+  // Relative indirect jump.
+  if (old_u8[0] == 0xff && old_u8[1] == 0x25) {
+    sptr relative_offset = *(s32*)(old_func + 2);
+    uptr* absolute_target_ptr = (uptr*)(old_func + 6 + relative_offset);
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thurstond wrote:

Nit: replace 6 with kIndirectJumpInstructionLength (currently defined as UNUSED in interception_win.cpp)


https://github.com/llvm/llvm-project/pull/222710