[asan][Darwin] Use Apples blocks extension only when supported (#72639)

[tob2]

Issue #72639

The commit at 020cdaf broke build of asan on macOS with GCC. GCC does not support the Apple blocks extension (yet). Uses of blocks in other parts of the sanitisers are protected by MISSING_BLOCKS_SUPPORT. But the type definition is not.

This applies FX's patch from the issue.

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Tobias Burnus (tob2)

Changes

Issue #72639

The commit at 020cdaf broke build of asan on macOS with GCC. GCC does not support the Apple blocks extension (yet). Uses of blocks in other parts of the sanitisers are protected by MISSING_BLOCKS_SUPPORT. But the type definition is not.

This applies FX's patch from the issue.

---

Full diff: https://github.com/llvm/llvm-project/pull/72642.diff

1 Files Affected:

• (modified) compiler-rt/lib/asan/asan_mac.cpp (+2)

diff --git a/compiler-rt/lib/asan/asan_mac.cpp b/compiler-rt/lib/asan/asan_mac.cpp
index 5d5146e0cde0ba9..6252fa20d5e740f 100644
--- a/compiler-rt/lib/asan/asan_mac.cpp
+++ b/compiler-rt/lib/asan/asan_mac.cpp
@@ -139,9 +139,11 @@ typedef void (*dispatch_mach_handler_function_t)(void *context,
                                                  dispatch_mach_reason reason,
                                                  dispatch_mach_msg_t message,
                                                  mach_error_t error);
+#if !defined(MISSING_BLOCKS_SUPPORT)
 typedef void (^dispatch_mach_handler_t)(dispatch_mach_reason reason,
                                         dispatch_mach_msg_t message,
                                         mach_error_t error);
+#endif
 
 // A wrapper for the ObjC blocks used to support libdispatch.
 typedef struct {

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[thesamesam]

LGTM but I can't formally approve.

[fxcoudert]

I can confirm that this patches fixes the build issue, and induces no regression in GCC. Could it be reviewed and merged? 🙏

[fxcoudert]

Thanks!