1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" 2 "http://www.w3.org/TR/html4/strict.dtd"> 3<html> 4<head> 5 <title>Clang Static Analyzer</title> 6 <link type="text/css" rel="stylesheet" href="content.css"> 7 <link type="text/css" rel="stylesheet" href="menu.css"> 8 <script type="text/javascript" src="scripts/menu.js"></script> 9 <!-- Generated from: http://www.spiffycorners.com/index.php --> 10 11<style type="text/css"> 12.spiffy{display:block} 13.spiffy *{ 14 display:block; 15 height:1px; 16 overflow:hidden; 17 font-size:.01em; 18 background:#EBF0FA} 19.spiffy1{ 20 margin-left:3px; 21 margin-right:3px; 22 padding-left:1px; 23 padding-right:1px; 24 border-left:1px solid #f6f8fc; 25 border-right:1px solid #f6f8fc; 26 background:#f0f3fb} 27.spiffy2{ 28 margin-left:1px; 29 margin-right:1px; 30 padding-right:1px; 31 padding-left:1px; 32 border-left:1px solid #fdfdfe; 33 border-right:1px solid #fdfdfe; 34 background:#eef2fa} 35.spiffy3{ 36 margin-left:1px; 37 margin-right:1px; 38 border-left:1px solid #eef2fa; 39 border-right:1px solid #eef2fa;} 40.spiffy4{ 41 border-left:1px solid #f6f8fc; 42 border-right:1px solid #f6f8fc} 43.spiffy5{ 44 border-left:1px solid #f0f3fb; 45 border-right:1px solid #f0f3fb} 46.spiffyfg{ 47 background:#EBF0FA} 48 49.spiffyfg h2 { 50 margin:0px; padding:10px; 51} 52 53 #left { float:left; } 54 #left h2 { margin:1px; padding-top:0px; } 55 #right { float:left; margin-left:20px; margin-right:20px; padding:0px ;} 56 #right h2 { padding:0px; margin:0px; } 57 #wrappedcontent { padding:15px;} 58</style> 59</head> 60<body> 61 62<div id="page"> 63<!--#include virtual="menu.html.incl"--> 64<div id="content"> 65 66 67<table style="margin-top:0px" width="100%" border="0" cellpadding="0px" cellspacing="0"> 68<tr><td> 69 70<h1>Clang Static Analyzer</h1> 71 72<p>The Clang Static Analyzer is source code analysis tool that find bugs in C 73and Objective-C programs.</p> 74 75<p>Currently it can be run either as a <a href="/scan-build.html">standalone 76tool</a> or <a href="/xcode.html">within Xcode</a>. The standalone tool is 77invoked from the command-line, and is intended to be run in tandem with a build 78of a codebase.</p> 79 80<p>The analyzer is 100% open source and is part of the <a 81href="http://clang.llvm.org">Clang</a> project. Like the rest of Clang, the 82analyzer is implemented as a C++ library that can be used by other tools and 83applications.</p> 84 85<h2>Download</h2> 86 87<div style="padding:0px; font-size: 90%"> 88 <b class="spiffy"> 89 <b class="spiffy1"><b></b></b> 90 <b class="spiffy2"><b></b></b> 91 <b class="spiffy3"></b> 92 <b class="spiffy4"></b> 93 <b class="spiffy5"></b></b> 94 <div class="spiffyfg"> 95 <div style="padding:15px"> 96 <h3 style="margin:0px;padding:0px">Mac OS X</h3> 97 <ul> 98 <li>Latest build (Intel-only binary, 10.5+):<br> 99 <!--#include virtual="latest_checker.html.incl"--> 100 </li> 101 <li><a href="/release_notes.html">Release notes</a></li> 102 <li>This build can be used both from the command line and from within Xcode</li> 103 <li><a href="/installation.html">Installation</a> and <a href="/scan-build.html">usage</a></li> 104 </ul> 105 </div> 106 </div> 107 <b class="spiffy"> 108 <b class="spiffy5"></b> 109 <b class="spiffy4"></b> 110 <b class="spiffy3"></b> 111 <b class="spiffy2"><b></b></b> 112 <b class="spiffy1"><b></b></b></b> 113</div> 114 115<div style="padding:0; margin-top:10px; font-size: 90%"> 116 <b class="spiffy"> 117 <b class="spiffy1"><b></b></b> 118 <b class="spiffy2"><b></b></b> 119 <b class="spiffy3"></b> 120 <b class="spiffy4"></b> 121 <b class="spiffy5"></b></b> 122 <div class="spiffyfg"> 123 <div style="padding:15px"> 124 <h3 style="margin:0px;padding:0px">Other Platforms</h3> 125 <p>For other platforms, please follow the instructions for <a 126 href="/installation#OtherPlatforms">building the analyzer</a> from 127 source code.<p> 128 </div> 129 </div> 130 <b class="spiffy"> 131 <b class="spiffy5"></b> 132 <b class="spiffy4"></b> 133 <b class="spiffy3"></b> 134 <b class="spiffy2"><b></b></b> 135 <b class="spiffy1"><b></b></b></b> 136</div> 137 138 139</td><td style="padding-left:10px"> 140<a href="images/analyzer_xcode.png"><img src="images/analyzer_xcode.png" width="450" alt="analyzer in xcode"></a> 141<div style="text-align:center"><b>Viewing static analyzer results in Xcode 3.2</b></div> 142<a href="images/analyzer_html.png"><img src="images/analyzer_html.png" width="450" alt="analyzer in browser"></a> 143<div style="text-align:center"><b>Viewing static analyzer results in a web browser</b></div> 144</td></tr></table> 145 146<h2 id="StaticAnalysis">What is Static Analysis?</h2> 147 148<p>The term "static analysis" is conflated, but here we use it to mean 149a collection of algorithms and techniques used to analyze source code in order 150to automatically find bugs. The idea is similar in spirit to compiler warnings 151(which can be useful for finding coding errors) but to take that idea a step 152further and find bugs that are traditionally found using run-time debugging 153techniques such as testing.</p> 154 155<p>Static analysis bug-finding tools have evolved over the last several decades 156from basic syntactic checkers to those that find deep bugs by reasoning about 157the semantics of code. The goal of the Clang Static Analyzer is to provide a 158industrial-quality static analysis framework for analyzing C and Objective-C 159programs that is freely available, extensible, and has a high quality of 160implementation.</p> 161 162<h3 id="Clang">Part of Clang and LLVM</h3> 163 164<p>As its name implies, the Clang Static Analyzer is built on top of <a 165href="http://clang.llvm.org">Clang</a> and <a href="http://llvm.org">LLVM</a>. 166Strictly speaking, the analyzer is part of Clang, as Clang consists of a set of 167reusable C++ libraries for building powerful source-level tools. The static 168analysis engine used by the Clang Static Analyzer is a Clang library, and has 169the capability to be reused in different contexts and by different clients.</p> 170 171<h2>Important Points to Consider</h2> 172 173<p>While we believe that the static analyzer is already very useful for finding 174bugs, we ask you to bear in mind a few points when using it.</p> 175 176<h3>Work-in-Progress</h3> 177 178<p>The analyzer is a continuous work-in-progress. 179There are many planned enhancements to improve both the precision and scope of 180its analysis algorithms as well as the kinds bugs it will find. While there are 181fundamental limitations to what static analysis can do, we have a long way to go 182before hitting that wall.</p> 183 184<h3>Slower than Compilation</h3> 185 186<p>Operationally, using static analysis to 187automatically find deep program bugs is about trading CPU time for the hardening 188of code. Because of the deep analysis performed by state-of-the-art static 189analysis tools, static analysis can be much slower than compilation.</p> 190 191<p>While the Clang Static Analyzer is being designed to be as fast and 192light-weight as possible, please do not expect it to be as fast as compiling a 193program (even with optimizations enabled). Some of the algorithms needed to find 194bugs require in the worst case exponential time.</p> 195 196<p>The Clang Static Analyzer runs in a reasonable amount of time by both 197bounding the amount of checking work it will do as well as using clever 198algorithms to reduce the amount of work it must do to find bugs.</p> 199 200<h3>False Positives</h3> 201 202<p>Static analysis is not perfect. It can falsely flag bugs in a program where 203the code behaves correctly. Because some code checks require more analysis 204precision than others, the frequency of false positives can vary widely between 205different checks. Our long-term goal is to have the analyzer have a low false 206positive rate for most code on all checks.</p> 207 208<p>Please help us in this endeavor by <a href="filing_bugs.html">reporting false 209positives</a>. False positives cannot be addressed unless we know about 210them.</p> 211 212<h3>More Checks</h3> 213 214<p>Static analysis is not magic; a static analyzer can only find bugs that it 215has been specifically engineered to find. If there are specific kinds of bugs 216you would like the Clang Static Analyzer to find, please feel free to 217file <a href="filing_bugs.html">feature requests</a> or contribute your own 218patches.</p> 219 220</div> 221</div> 222</body> 223</html> 224 225