llvm-project/clang/docs/LeakSanitizer.rst

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LeakSanitizer
================
.. contents::
:local:
Introduction
============
LeakSanitizer is a run-time memory leak detector. It can be combined with
:doc:`AddressSanitizer` to get both memory error and leak detection, or
used in a stand-alone mode. LSan adds almost no performance overhead
until the very end of the process, at which point there is an extra leak
detection phase.
Usage
=====
LeakSanitizer is only supported on x86\_64 Linux. In order to use it,
simply build your program with :doc:`AddressSanitizer`:
.. code-block:: console
$ cat memory-leak.c
#include <stdlib.h>
void *p;
int main() {
p = malloc(7);
p = 0; // The memory is leaked here.
return 0;
}
% clang -fsanitize=address -g memory-leak.c ; ./a.out
==23646==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 7 byte(s) in 1 object(s) allocated from:
#0 0x4af01b in __interceptor_malloc /projects/compiler-rt/lib/asan/asan_malloc_linux.cc:52:3
#1 0x4da26a in main memory-leak.c:4:7
#2 0x7f076fd9cec4 in __libc_start_main libc-start.c:287
SUMMARY: AddressSanitizer: 7 byte(s) leaked in 1 allocation(s).
To use LeakSanitizer in stand-alone mode, link your program with
``-fsanitize=leak`` flag. Make sure to use ``clang`` (not ``ld``) for the
link step, so that it would link in proper LeakSanitizer run-time library
into the final executable.
More Information
================
`<https://github.com/google/sanitizers/wiki/AddressSanitizerLeakSanitizer>`_