[asan][test] Additional test requiring weak symbol for dyld64.

[rsundahl]

Summary

Extension of D127929

rdar://80997227

[rsundahl]

Addon to D127929.

[thetruestblue]

Thanks. Are we keeping track of these somewhere, in a radar perhaps, so if there's ever a more efficient abstraction/fix we know what files we have touched?

[MaskRay]

Thanks for the fix. I wish that future macOS dyld can fix the functionality regression ;-)

compiler-rt/test/asan/TestCases/Posix/free_hook_realloc.cpp

 // Check that free hook doesn't conflict with Realloc.
 // RUN: %clangxx_asan -O2 %s -o %t
 // RUN: %run %t 2>&1 | FileCheck %s
 
 #include <stdlib.h>
 #include <unistd.h>
 #include <sanitizer/allocator_interface.h>
 
 static void *glob_ptr;
 
-extern "C" {
-void __sanitizer_free_hook(const volatile void *ptr) {
+// Required for dyld macOS 12.0+
+#if (__APPLE__)
+__attribute__((weak))
+#endif
+extern "C" void
+__sanitizer_free_hook(const volatile void *ptr) {
   if (ptr == glob_ptr) {
     *(int*)ptr = 0;
     write(1, "FreeHook\n", sizeof("FreeHook\n"));
   }
 }
-}
 
 int main() {
   int *x = (int*)malloc(100);
   x[0] = 42;
   glob_ptr = x;
   int *y = (int*)realloc(x, 200);
   // Verify that free hook was called and didn't spoil the memory.
   if (y[0] != 42) {
     _exit(1);
   }
   write(1, "Passed\n", sizeof("Passed\n"));
   free(y);
   // CHECK: FreeHook
   // CHECK: Passed
   return 0;
 }

compiler-rt/test/memprof/TestCases/free_hook_realloc.cpp

 // Check that free hook doesn't conflict with Realloc.
 // RUN: %clangxx_memprof -O2 %s -o %t && %run %t 2>&1 | FileCheck %s
 
 #include <sanitizer/allocator_interface.h>
 #include <stdlib.h>
 #include <unistd.h>
 
 static void *glob_ptr;
 
-extern "C" {
-void __sanitizer_free_hook(const volatile void *ptr) {
+// (Speculative fix if memprof is enabled on Apple platforms)
+// Required for dyld macOS 12.0+
+#if (__APPLE__)
+__attribute__((weak))
+#endif
+extern "C" void
+__sanitizer_free_hook(const volatile void *ptr) {
   if (ptr == glob_ptr) {
     *(int *)ptr = 0;
     write(1, "FreeHook\n", sizeof("FreeHook\n"));
   }
 }
-}
 
 int main() {
   int *x = (int *)malloc(100);
   x[0] = 42;
   glob_ptr = x;
   int *y = (int *)realloc(x, 200);
   // Verify that free hook was called and didn't spoil the memory.
   if (y[0] != 42) {
     _exit(1);
   }
   write(1, "Passed\n", sizeof("Passed\n"));
   free(y);
   // CHECK: FreeHook
   // CHECK: Passed
   return 0;
 }