[compiler-rt] [Darwin][ASan][Test] Create a noinlined wrapper function for reliable suppression in test. (PR #131194)

[Paddy McDonald via llvm-commits]

================
@@ -13,12 +13,17 @@
 
 #include <CoreFoundation/CoreFoundation.h>
 
+// Use a noinline wrapper function to suppress to stabilize test.
+__attribute__((noinline)) CFStringRef createCFString(const unsigned char *bytes,
+                                                     CFIndex length) {
+  return CFStringCreateWithBytes(kCFAllocatorDefault, bytes, length,
+                                 kCFStringEncodingUTF8, FALSE);
+}
+
 int main() {
   char *a = (char *)malloc(6);
   strcpy(a, "hello");
-  CFStringRef str =
-      CFStringCreateWithBytes(kCFAllocatorDefault, (unsigned char *)a, 10,
-                              kCFStringEncodingUTF8, FALSE);  // BOOM
+  CFStringRef str = createCFString((unsigned char *)a, 10); // BOOM
----------------
padriff wrote:

`CFStringCreateWithBytes` isn't being inlined into the test code.  Rather there is an optimization (tail call) in CoreFoundation that means `CFStringCreateWithBytes` is effectively removed from the stack.

Wrapping the function in the test code allows us to protect against this and future optimizations in the external code.

https://github.com/llvm/llvm-project/pull/131194