blob: d47eb0a62c894c1eb96eadc753ae67d3151de140 [file] [log] [blame]
<!-- Material used from: HTML 4.01 specs: -->
<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>AddressSanitizer, a fast memory error detector</title>
<link type="text/css" rel="stylesheet" href="../menu.css">
<link type="text/css" rel="stylesheet" href="../content.css">
<style type="text/css">
td {
vertical-align: top;
<!--#include virtual="../menu.html.incl"-->
<div id="content">
<li> <a href="intro">Introduction</a>
<li> <a href="howtobuild">How to Build</a>
<li> <a href="usage">Usage</a>
<ul><li> <a href="has_feature">__has_feature(address_sanitizer)</a></ul>
<li> <a href="platforms">Supported Platforms</a>
<li> <a href="limitations">Limitations</a>
<li> <a href="status">Current Status</a>
<li> <a href="moreinfo">More Information</a>
<h2 id="intro">Introduction</h2>
AddressSanitizer is a fast memory error detector.
It consists of a compiler instrumentation module and a run-time library.
The tool can detect the following types of bugs:
<ul> <li> Out-of-bounds accesses to heap, stack and globals
<li> Use-after-free
<li> Use-after-return (to some extent)
<li> Double-free, invalid free
Typical slowdown introduced by AddressSanitizer is <b>2x</b>.
<h2 id="howtobuild">How to build</h2>
Follow the <a href="../get_started.html">clang build instructions</a>.
<h2 id="usage">Usage</h2>
Simply compile and link your program with <tt>-faddress-sanitizer</tt> flag. <BR>
To get a reasonable performance add <tt>-O1</tt> or higher. <BR>
To get nicer stack traces in error messages add
<tt>-fno-omit-frame-pointer</tt>. <BR>
To get perfect stack traces you may need to disable inlining (just use <tt>-O1</tt>) and tail call
elimination (</tt>-fno-optimize-sibling-calls</tt>).
% cat
int main(int argc, char **argv) {
int *array = new int[100];
delete [] array;
return array[argc]; // BOOM
% clang -O1 -g -faddress-sanitizer -fno-omit-frame-pointer
If a bug is detected, the program will print an error message to stderr and exit with a
non-zero exit code.
Currently, AddressSanitizer does not symbolize its output, so you may need to use a
separate script to symbolize the result offline (this will be fixed in future).
% ./a.out 2> log
% projects/compiler-rt/lib/asan/scripts/ / < log | c++filt
==9442== ERROR: AddressSanitizer heap-use-after-free on address 0x7f7ddab8c084 at pc 0x403c8c bp 0x7fff87fb82d0 sp 0x7fff87fb82c8
READ of size 4 at 0x7f7ddab8c084 thread T0
#0 0x403c8c in main
#1 0x7f7ddabcac4d in __libc_start_main ??:0
0x7f7ddab8c084 is located 4 bytes inside of 400-byte region [0x7f7ddab8c080,0x7f7ddab8c210)
freed by thread T0 here:
#0 0x404704 in operator delete[](void*) ??:0
#1 0x403c53 in main
#2 0x7f7ddabcac4d in __libc_start_main ??:0
previously allocated by thread T0 here:
#0 0x404544 in operator new[](unsigned long) ??:0
#1 0x403c43 in main
#2 0x7f7ddabcac4d in __libc_start_main ??:0
==9442== ABORTING
<h3 id="has_feature">__has_feature(address_sanitizer)</h3>
In some cases one may need to execute different code depending on whether
AddressSanitizer is enabled.
<a href="LanguageExtensions.html#__has_feature_extension">__has_feature</a>
can be used for this purpose.
#if defined(__has_feature) &amp;&amp; __has_feature(address_sanitizer)
code that runs only under AddressSanitizer
code that does not run under AddressSanitizer
<h2 id="platforms">Supported Platforms</h2>
AddressSanitizer is supported on
<ul><li>Linux x86_64 (tested on Ubuntu 10.04).
<li>MacOS 10.6 i386/x86_64.
Support for Linux i386/ARM and MacOS 10.7 is in progress.
<h2 id="limitations">Limitations</h2>
<li> AddressSanitizer uses more real memory than a native run.
How much -- depends on the allocations sizes. The smaller the
allocations you make the bigger the overhead.
<li> On 64-bit platforms AddressSanitizer maps (but not reserves)
16+ Terabytes of virtual address space.
This means that tools like <tt>ulimit</tt> may not work as usually expected.
<li> Static linking is not supported.
<h2 id="status">Current Status</h2>
AddressSanitizer is fully functional on supported platforms in LLVM head.
However, the test suite is not fully integrated yet and we lack the testing
process (buildbots).
<h2 id="moreinfo">More Information</h2>
<a href=""></a>.