[TSan] Fix asan_mac.cpp function pointer cast warnings #151517

DanBlackwell · 2025-07-31T13:17:58Z

Fixes these compiler warnings:

.../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:252:4: warning: cast from 'dispatch_function_t' (aka 'void (*)(void *)') to 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') converts to incompatible function type [-Wcast-function-type-mismatch]
  252 |   ((void (*)(void *, size_t))asan_ctxt->func)(asan_ctxt->block, iteration);
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:259:32: warning: cast from 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') to 'dispatch_function_t' (aka 'void (*)(void *)') converts to incompatible function type [-Wcast-function-type-mismatch]
  259 |       alloc_asan_context(ctxt, (dispatch_function_t)work, &stack);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~

llvmbot · 2025-07-31T13:18:28Z

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

Author: Dan Blackwell (DanBlackwell)

Changes

Fixes these compiler warnings:

.../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:252:4: warning: cast from 'dispatch_function_t' (aka 'void (*)(void *)') to 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') converts to incompatible function type [-Wcast-function-type-mismatch]
  252 |   ((void (*)(void *, size_t))asan_ctxt-&gt;func)(asan_ctxt-&gt;block, iteration);
      |    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:259:32: warning: cast from 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') to 'dispatch_function_t' (aka 'void (*)(void *)') converts to incompatible function type [-Wcast-function-type-mismatch]
  259 |       alloc_asan_context(ctxt, (dispatch_function_t)work, &amp;stack);
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~

Full diff: https://github.com/llvm/llvm-project/pull/151517.diff

1 Files Affected:

(modified) compiler-rt/lib/asan/asan_mac.cpp (+18-10)

diff --git a/compiler-rt/lib/asan/asan_mac.cpp b/compiler-rt/lib/asan/asan_mac.cpp
index 1f3c79eec125b..99fea6de595d7 100644
--- a/compiler-rt/lib/asan/asan_mac.cpp
+++ b/compiler-rt/lib/asan/asan_mac.cpp
@@ -130,6 +130,7 @@ typedef void* dispatch_queue_t;
 typedef void* dispatch_source_t;
 typedef u64 dispatch_time_t;
 typedef void (*dispatch_function_t)(void *block);
+typedef void (*dispatch_apply_function_t)(void *, size_t);
 typedef void* (*worker_t)(void *block);
 typedef unsigned long dispatch_mach_reason;
 typedef void *dispatch_mach_msg_t;
@@ -149,7 +150,11 @@ typedef void (^dispatch_mach_handler_t)(dispatch_mach_reason reason,
 // A wrapper for the ObjC blocks used to support libdispatch.
 typedef struct {
   void *block;
-  dispatch_function_t func;
+  union {
+    dispatch_function_t dispatch_func;
+    dispatch_apply_function_t dispatch_apply_func;
+    static_assert(sizeof(dispatch_func) == sizeof(dispatch_apply_func));
+  };
   u32 parent_tid;
 } asan_block_context_t;
 
@@ -177,7 +182,7 @@ void asan_dispatch_call_block_and_release(void *block) {
           block, (void*)pthread_self());
   asan_register_worker_thread(context->parent_tid, &stack);
   // Call the original dispatcher for the block.
-  context->func(context->block);
+  context->dispatch_func(context->block);
   asan_free(context, &stack);
 }
 
@@ -193,7 +198,7 @@ asan_block_context_t *alloc_asan_context(void *ctxt, dispatch_function_t func,
   asan_block_context_t *asan_ctxt =
       (asan_block_context_t*) asan_malloc(sizeof(asan_block_context_t), stack);
   asan_ctxt->block = ctxt;
-  asan_ctxt->func = func;
+  asan_ctxt->dispatch_func = func;
   asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
   return asan_ctxt;
 }
@@ -249,14 +254,17 @@ extern "C" void asan_dispatch_apply_f_work(void *context, size_t iteration) {
   GET_STACK_TRACE_THREAD;
   asan_block_context_t *asan_ctxt = (asan_block_context_t *)context;
   asan_register_worker_thread(asan_ctxt->parent_tid, &stack);
-  ((void (*)(void *, size_t))asan_ctxt->func)(asan_ctxt->block, iteration);
+  asan_ctxt->dispatch_apply_func(asan_ctxt->block, iteration);
 }
 
 INTERCEPTOR(void, dispatch_apply_f, size_t iterations, dispatch_queue_t queue,
-            void *ctxt, void (*work)(void *, size_t)) {
+            void *ctxt, dispatch_apply_function_t work) {
   GET_STACK_TRACE_THREAD;
   asan_block_context_t *asan_ctxt =
-      alloc_asan_context(ctxt, (dispatch_function_t)work, &stack);
+      (asan_block_context_t *)asan_malloc(sizeof(asan_block_context_t), &stack);
+  asan_ctxt->block = ctxt;
+  asan_ctxt->dispatch_apply_func = work;
+  asan_ctxt->parent_tid = GetCurrentTidOrInvalid();
   REAL(dispatch_apply_f)(iterations, queue, (void *)asan_ctxt,
                          asan_dispatch_apply_f_work);
 }
@@ -280,10 +288,10 @@ dispatch_mach_t dispatch_mach_create(const char *label, dispatch_queue_t queue,
 #define GET_ASAN_BLOCK(work) \
   void (^asan_block)(void);  \
   int parent_tid = GetCurrentTidOrInvalid(); \
-  asan_block = ^(void) { \
-    GET_STACK_TRACE_THREAD; \
-    asan_register_worker_thread(parent_tid, &stack); \
-    work(); \
+  asan_block = ^(void) {                   \
+        GET_STACK_TRACE_THREAD;                          \
+        asan_register_worker_thread(parent_tid, &stack); \
+        work(); \
   }
 
 INTERCEPTOR(void, dispatch_async,

github-actions · 2025-07-31T13:20:32Z

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff HEAD~1 HEAD --extensions cpp -- compiler-rt/lib/asan/asan_mac.cpp

View the diff from clang-format here.

diff --git a/compiler-rt/lib/asan/asan_mac.cpp b/compiler-rt/lib/asan/asan_mac.cpp
index a68e362e0..99fea6de5 100644
--- a/compiler-rt/lib/asan/asan_mac.cpp
+++ b/compiler-rt/lib/asan/asan_mac.cpp
@@ -288,10 +288,10 @@ dispatch_mach_t dispatch_mach_create(const char *label, dispatch_queue_t queue,
 #define GET_ASAN_BLOCK(work) \
   void (^asan_block)(void);  \
   int parent_tid = GetCurrentTidOrInvalid(); \
-  asan_block = ^(void) { \
-    GET_STACK_TRACE_THREAD; \
-    asan_register_worker_thread(parent_tid, &stack); \
-    work(); \
+  asan_block = ^(void) {                   \
+        GET_STACK_TRACE_THREAD;                          \
+        asan_register_worker_thread(parent_tid, &stack); \
+        work(); \
   }
 
 INTERCEPTOR(void, dispatch_async,

thetruestblue · 2025-08-01T03:10:27Z

compiler-rt/lib/asan/asan_mac.cpp

Is this change related to the fix or is it to appease clang format?

It was indeed for clang-format. But I didn't touch that code, so I've reset it back now.

thetruestblue · 2025-08-01T14:09:55Z

Thanks for fixing this up after it got past me.

Fixes these compiler warnings: ``` .../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:252:4: warning: cast from 'dispatch_function_t' (aka 'void (*)(void *)') to 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') converts to incompatible function type [-Wcast-function-type-mismatch] 252 | ((void (*)(void *, size_t))asan_ctxt->func)(asan_ctxt->block, iteration); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:259:32: warning: cast from 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') to 'dispatch_function_t' (aka 'void (*)(void *)') converts to incompatible function type [-Wcast-function-type-mismatch] 259 | alloc_asan_context(ctxt, (dispatch_function_t)work, &stack); | ^~~~~~~~~~~~~~~~~~~~~~~~~ ``` (cherry picked from commit e7e7494)

Author: Dan Blackwell [email protected] Date: Fri Aug 1 16:33:23 2025 +0100 [TSan] Fix asan_mac.cpp function pointer cast warnings (llvm#151517) Fixes these compiler warnings: .../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:252:4: warning: cast from 'dispatch_function_t' (aka 'void (*)(void *)') to 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') converts to incompatible function type [-Wcast-function-type-mismatch] 252 | ((void (*)(void *, size_t))asan_ctxt->func)(asan_ctxt->block, iteration); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:259:32: warning: cast from 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') to 'dispatch_function_t' (aka 'void (*)(void *)') converts to incompatible function type [-Wcast-function-type-mismatch] 259 | alloc_asan_context(ctxt, (dispatch_function_t)work, &stack); | ^~~~~~~~~~~~~~~~~~~~~~~~~ (cherry picked from commit e7e7494) [ASan][Darwin][GCD] Add interceptor for dispatch_apply (llvm#149238) ASan had a gap in coverage for wqthreads blocks submitted by dispatch_apply This adds interceptor for dispatch_apply and dispatch_apply_f and adds a test that a failure in a dispatch apply block contains thread and stack info. rdar://139660648 (cherry picked from commit 5ce04b4)

Fixes these compiler warnings: ``` .../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:252:4: warning: cast from 'dispatch_function_t' (aka 'void (*)(void *)') to 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') converts to incompatible function type [-Wcast-function-type-mismatch] 252 | ((void (*)(void *, size_t))asan_ctxt->func)(asan_ctxt->block, iteration); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .../llvm-project/compiler-rt/lib/asan/asan_mac.cpp:259:32: warning: cast from 'void (*)(void *, size_t)' (aka 'void (*)(void *, unsigned long)') to 'dispatch_function_t' (aka 'void (*)(void *)') converts to incompatible function type [-Wcast-function-type-mismatch] 259 | alloc_asan_context(ctxt, (dispatch_function_t)work, &stack); | ^~~~~~~~~~~~~~~~~~~~~~~~~ ``` (cherry picked from commit e7e7494)

llvmbot added compiler-rt compiler-rt:asan Address sanitizer compiler-rt:sanitizer labels Jul 31, 2025

DanBlackwell force-pushed the fix-asan-mac-warnings branch from 5ca1b54 to 1c4e83d Compare July 31, 2025 13:40

thetruestblue reviewed Aug 1, 2025

View reviewed changes

[TSan] Fix asan_mac.cpp function pointer cast warnings

0a743fa

DanBlackwell force-pushed the fix-asan-mac-warnings branch from 1c4e83d to 0a743fa Compare August 1, 2025 10:36

thetruestblue approved these changes Aug 1, 2025

View reviewed changes

thetruestblue merged commit e7e7494 into llvm:main Aug 1, 2025
8 of 9 checks passed

thetruestblue mentioned this pull request Sep 14, 2025

Add dispatch apply swiftlang/llvm-project#11409

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