[Asan][Darwin][GCD] Add interceptor for dispatch_mach_create_f

[thetruestblue]

Summary

When enabling DriverKit on iOS, Address Sanitizer was unable to
intercept thread creation directly for dispatch workerthreads.

Because of this calls to GetStackTraceFromID failed and ASan was
unable to capture a meaningful stack trace.

This patch adds an interceptor for a dispatch function as a proxy
that is "close enough" to thread creation so that ASan is able
to meaningfully capture and register the dispatched thread.

Note: I propose not adding a test for this change.
Because this change is only meaningful in such a narrow usecase on Darwin
and is incredibly difficult to add a meaningful test for this externally.

[yln]

LGTM, with nits:

• Remove debugging leftover
• Make sure to run clang-format on the modified/added parts of the file.

compiler-rt/lib/asan/asan_mac.cpp

324–327

Remove debugging leftover?

[thetruestblue]

Ran clang-format and removed debugging leftovers.

compiler-rt/lib/asan/asan_mac.cpp

 typedef u64 dispatch_time_t;
 typedef void (*dispatch_function_t)(void *block);
 typedef void* (*worker_t)(void *block);
+typedef unsigned long dispatch_mach_reason;
+typedef void *dispatch_mach_msg_t;
+typedef int mach_error_t;
+typedef void *dispatch_mach_t;
+
+typedef void (*dispatch_mach_handler_function_t)(void *context,
+                                                 dispatch_mach_reason reason,
+                                                 dispatch_mach_msg_t message,
+                                                 mach_error_t error);
+typedef void (^dispatch_mach_handler_t)(dispatch_mach_reason reason,
+                                        dispatch_mach_msg_t message,
+                                        mach_error_t error);
 
 // A wrapper for the ObjC blocks used to support libdispatch.
 typedef struct {

 void dispatch_source_set_cancel_handler(dispatch_source_t ds,
                                         void(^work)(void));
 void dispatch_source_set_event_handler(dispatch_source_t ds, void(^work)(void));
+dispatch_mach_t dispatch_mach_create(const char *label, dispatch_queue_t queue,
+                                     dispatch_mach_handler_t handler);
 }
 
 #define GET_ASAN_BLOCK(work) \

   GET_ASAN_BLOCK(work);
   REAL(dispatch_source_set_event_handler)(ds, asan_block);
 }
+
+INTERCEPTOR(void *, dispatch_mach_create, const char *label,
+            dispatch_queue_t dq, dispatch_mach_handler_t handler) {
+  int parent_tid = GetCurrentTidOrInvalid();
+  return REAL(dispatch_mach_create)(
+      label, dq,
+      ^(dispatch_mach_reason reason, dispatch_mach_msg_t message,
+        mach_error_t error) {
+        GET_STACK_TRACE_THREAD;
+        asan_register_worker_thread(parent_tid, &stack);
+        handler(reason, message, error);
+      });
+}
+
+INTERCEPTOR(void *, dispatch_mach_create_f, const char *label,
+            dispatch_queue_t dq, void *ctxt,
+            dispatch_mach_handler_function_t handler) {
+  int parent_tid = GetCurrentTidOrInvalid();
+  return REAL(dispatch_mach_create)(
+      label, dq,
+      ^(dispatch_mach_reason reason, dispatch_mach_msg_t message,
+        mach_error_t error) {
+        GET_STACK_TRACE_THREAD;
+        asan_register_worker_thread(parent_tid, &stack);
+        handler(ctxt, reason, message, error);
+      });
+}
+
 #endif
 
 #endif  // SANITIZER_APPLE