How to use clang's LeakSanitizer on MacOS?

Question

I'm macOS Big Sur. AFAIK, Valgrind doesn't support this OS yet. At least I've tried this.

After some Googling, I switched to LeakSanitizier and tested this C code:

#include <stdlib.h>
void *p;
int main() {
  p = malloc(7);
  p = 0; // The memory is leaked here.
  return 0;
}

This post pointed that clang shipped with macOS doesn't have -fsanitize=address support enabled. So I installed clang from homebrew:

/usr/local/opt/llvm/bin/clang --version
clang version 11.0.0
Target: x86_64-apple-darwin20.1.0
Thread model: posix
InstalledDir: /usr/local/opt/llvm/bin

OK, let's try it:

Ancalagon:Codes anta40$ /usr/local/opt/llvm/bin/clang -g -fsanitize=address leak1.c -o leak1
Ancalagon:Codes anta40$ ./leak1
Ancalagon:Codes anta40$

Nothing happens. Perhaps try llvm-symbolizer

Ancalagon:Codes anta40$ /usr/local/opt/llvm/bin/llvm-symbolizer ./leak1
./leak1

Same result. Perhaps I'm missing something here?

Answer 1

To enable LeakSanitizer set ASAN_OPTIONS=detect_leaks=1 or use -fsanitize=leak flag.

Also, according to this, if using the clang version 11.0 and Xcode version 11.3, use clang with -mlinker-version=450 flag to avoid a linker error.

Example:

$ /usr/local/opt/llvm/bin/clang -g -fsanitize=address leak1.c -o leak1
$ ASAN_OPTIONS=detect_leaks=1 ./leak1

or

$ /usr/local/opt/llvm/bin/clang -g -fsanitize=leak leak1.c -o leak1
$ ./leak1