如何使用Clang查找内存泄漏

Question

I have installed Clang in my machine (ubuntu) in order to find memory leaks in my C code. I wrote a sample code in order to check the working of it which is as follows:

/* File: hello.c for leak detection */
#include <stdio.h>
#include <stdlib.h>

void *x;

int main() {
  x = malloc(2);
  x = 0; // Memory leak
  return 0;
}

I found some options in internet to compile like

$ scan-build clang --analyze hello.c

and

$ scan-build clang -fsanitize=address hello.c

But none of them are showing any signs of memory leak.

scan-build: Using '/usr/bin/clang' for static analysis
scan-build: Removing directory '/tmp/scan-build-2015-07-02-122717-16928-1' because it contains no reports.
scan-build: No bugs found.

Can anyone kindly tell how to correctly use Clang for Memory leak detection.

Answer 1

Interestingly, the clang static analyzer finds the memory leak if you declare void *x inside main :

int main() {
  void *x = malloc(2);
  x = 0; // Memory leak
  return 0;
}

Analyzing this code by running:

scan-build clang -g hello.c

gives a warning like:

hello.c:9:3: warning: Potential leak of memory pointed to by 'x'
  return 0;
  ^~~~~~~~