www/analyzer/index.html - fp2-dev/platform/external/clang - Gitiles

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 <tr><td>

 <h1>Clang Static Analyzer</h1>

 <p>The Clang Static Analyzer is source code analysis tool that find bugs in C
 and Objective-C programs.</p>

 <p>Currently it can be run either as a <a href="/scan-build.html">standalone
 tool</a> or <a href="/xcode.html">within Xcode</a>. The standalone tool is
 invoked from the command-line, and is intended to be run in tandem with a build
 of a codebase.</p>

 <p>The analyzer is 100% open source and is part of the <a
 href="http://clang.llvm.org">Clang</a> project. Like the rest of Clang, the
 analyzer is implemented as a C++ library that can be used by other tools and
 applications.</p>

 <h2>Download</h2>

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    <h3 style="margin:0px;padding:0px">Mac OS X</h3>
    <ul>
     <li>Latest build (Universal binary, 10.5+):<br>
      <!--#include virtual="latest_checker.html.incl"-->
     </li>
     <li>Can be used both from the command line and within Xcode</li>
     <li><a href="/installation.html">Installation</a> and <a
     href="/scan-build.html">usage</a></li>
    </ul>
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   <div style="padding:15px">
    <h3 style="margin:0px;padding:0px">Other Platforms</h3>
    <p>For other platforms, please follow the instructions for <a
    href="/installation#OtherPlatforms">building the analyzer</a> from
    source code.<p>
   </div>
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 </td><td style="padding-left:10px">
 <a href="images/analyzer_xcode.png"><img src="images/analyzer_xcode.png" width="450x" border=0></a>
 <center><b>Viewing static analyzer results in Xcode 3.2</b></center>
 <a href="images/analyzer_html.png"><img src="images/analyzer_html.png" width="450px" border=0></a>
 <center><b>Viewing static analyzer results in a web browser</b></center>
 </td></tr></table>

 <h2 id="StaticAnalysis">What is Static Analysis?</h2>

 <p>The term &quot;static analysis&quot; is conflated, but here we use it to mean
 a collection of algorithms and techniques used to analyze source code in order
 to automatically find bugs. The idea is similar in spirit to compiler warnings
 (which can be useful for finding coding errors) but to take that idea a step
 further and find bugs that are traditionally found using run-time debugging
 techniques such as testing.</p>

 <p>Static analysis bug-finding tools have evolved over the last several decades
 from basic syntactic checkers to those that find deep bugs by reasoning about
 the semantics of code. The goal of the Clang Static Analyzer is to provide a
 industrial-quality static analysis framework for analyzing C and Objective-C
 programs that is freely available, extensible, and has a high quality of
 implementation.</p>

 <h3 id="Clang">Part of Clang and LLVM</h3>

 <p>As its name implies, the Clang Static Analyzer is built on top of <a
 href="http://clang.llvm.org">Clang</a> and <a href="http://llvm.org">LLVM</a>.
 Strictly speaking, the analyzer is part of Clang, as Clang consists of a set of
 reusable C++ libraries for building powerful source-level tools. The static
 analysis engine used by the Clang Static Analyzer is a Clang library, and has
 the capability to be reused in different contexts and by different clients.</p>

 <h2>Important Points to Consider</h2>

 <p>While we believe that the static analyzer is already very useful for finding
 bugs, we ask you to bear in mind a few points when using it.</p>

 <h3>Work-in-Progress</h3>

 <p>The analyzer is a continuous work-in-progress.
 There are many planned enhancements to improve both the precision and scope of
 its analysis algorithms as well as the kinds bugs it will find. While there are
 fundamental limitations to what static analysis can do, we have a long way to go
 before hitting that wall.</p>

 <h3>Slower than Compilation</h3>

 <p>Operationally, using static analysis to
 automatically find deep program bugs is about trading CPU time for the hardening
 of code. Because of the deep analysis performed by state-of-the-art static
 analysis tools, static analysis can be much slower than compilation.</p>

 <p>While the Clang Static Analyzer is being designed to be as fast and
 light-weight as possible, please do not expect it to be as fast as compiling a
 program (even with optimizations enabled). Some of the algorithms needed to find
 bugs require in the worst case exponential time.</p>

 <p>The Clang Static Analyzer runs in a reasonable amount of time by both
 bounding the amount of checking work it will do as well as using clever
 algorithms to reduce the amount of work it must do to find bugs.</p></li>

 <h3>False Positives</h3>

 <p>Static analysis is not perfect. It can falsely flag bugs in a program where
 the code behaves correctly. Because some code checks require more analysis
 precision than others, the frequency of false positives can vary widely between
 different checks. Our long-term goal is to have the analyzer have a low false
 positive rate for most code on all checks.</p>

 <p>Please help us in this endeavor by <a href="filing_bugs.html">reporting false
 positives</a>. False positives cannot be addressed unless we know about
 them.</p>

 <h3>More Checks</h3>

 <p>Static analysis is not magic; a static analyzer can only find bugs that it
 has been specifically engineered to find. If there are specific kinds of bugs
 you would like the Clang Static Analyzer to find, please feel free to
 file <a href="filing_bugs.html">feature requests</a> or contribute your own
 patches.</p>

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	<div id="content">


	<table style="margin-top:0px" width="100%" border="0" cellpadding="0px" cellspacing="0">
	<tr><td>

	<h1>Clang Static Analyzer</h1>

	<p>The Clang Static Analyzer is source code analysis tool that find bugs in C
	and Objective-C programs.</p>

	<p>Currently it can be run either as a <a href="/scan-build.html">standalone
	tool</a> or <a href="/xcode.html">within Xcode</a>. The standalone tool is
	invoked from the command-line, and is intended to be run in tandem with a build
	of a codebase.</p>

	<p>The analyzer is 100% open source and is part of the <a
	href="http://clang.llvm.org">Clang</a> project. Like the rest of Clang, the
	analyzer is implemented as a C++ library that can be used by other tools and
	applications.</p>

	<h2>Download</h2>

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	#right h2 { padding:0px; margin:0px; }
	#wrappedcontent { padding:15px;}
	</style>

	<div style="padding:0px; font-size: 90%">
	<b class="spiffy">
	<b class="spiffy1"><b></b></b>
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	<b class="spiffy5"></b></b>
	<div class="spiffyfg">
	<div style="padding:15px">
	<h3 style="margin:0px;padding:0px">Mac OS X</h3>
	<ul>
	<li>Latest build (Universal binary, 10.5+):<br>
	<!--#include virtual="latest_checker.html.incl"-->
	</li>
	<li>Can be used both from the command line and within Xcode</li>
	<li><a href="/installation.html">Installation</a> and <a
	href="/scan-build.html">usage</a></li>
	</ul>
	</div>
	</div>
	<b class="spiffy">
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	<div class="spiffyfg">
	<div style="padding:15px">
	<h3 style="margin:0px;padding:0px">Other Platforms</h3>
	<p>For other platforms, please follow the instructions for <a
	href="/installation#OtherPlatforms">building the analyzer</a> from
	source code.<p>
	</div>
	</div>
	<b class="spiffy">
	<b class="spiffy5"></b>
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	</td><td style="padding-left:10px">
	<a href="images/analyzer_xcode.png"><img src="images/analyzer_xcode.png" width="450x" border=0></a>
	<center><b>Viewing static analyzer results in Xcode 3.2</b></center>
	<a href="images/analyzer_html.png"><img src="images/analyzer_html.png" width="450px" border=0></a>
	<center><b>Viewing static analyzer results in a web browser</b></center>
	</td></tr></table>

	<h2 id="StaticAnalysis">What is Static Analysis?</h2>

	<p>The term "static analysis" is conflated, but here we use it to mean
	a collection of algorithms and techniques used to analyze source code in order
	to automatically find bugs. The idea is similar in spirit to compiler warnings
	(which can be useful for finding coding errors) but to take that idea a step
	further and find bugs that are traditionally found using run-time debugging
	techniques such as testing.</p>

	<p>Static analysis bug-finding tools have evolved over the last several decades
	from basic syntactic checkers to those that find deep bugs by reasoning about
	the semantics of code. The goal of the Clang Static Analyzer is to provide a
	industrial-quality static analysis framework for analyzing C and Objective-C
	programs that is freely available, extensible, and has a high quality of
	implementation.</p>

	<h3 id="Clang">Part of Clang and LLVM</h3>

	<p>As its name implies, the Clang Static Analyzer is built on top of <a
	href="http://clang.llvm.org">Clang</a> and <a href="http://llvm.org">LLVM</a>.
	Strictly speaking, the analyzer is part of Clang, as Clang consists of a set of
	reusable C++ libraries for building powerful source-level tools. The static
	analysis engine used by the Clang Static Analyzer is a Clang library, and has
	the capability to be reused in different contexts and by different clients.</p>

	<h2>Important Points to Consider</h2>

	<p>While we believe that the static analyzer is already very useful for finding
	bugs, we ask you to bear in mind a few points when using it.</p>

	<h3>Work-in-Progress</h3>

	<p>The analyzer is a continuous work-in-progress.
	There are many planned enhancements to improve both the precision and scope of
	its analysis algorithms as well as the kinds bugs it will find. While there are
	fundamental limitations to what static analysis can do, we have a long way to go
	before hitting that wall.</p>

	<h3>Slower than Compilation</h3>

	<p>Operationally, using static analysis to
	automatically find deep program bugs is about trading CPU time for the hardening
	of code. Because of the deep analysis performed by state-of-the-art static
	analysis tools, static analysis can be much slower than compilation.</p>

	<p>While the Clang Static Analyzer is being designed to be as fast and
	light-weight as possible, please do not expect it to be as fast as compiling a
	program (even with optimizations enabled). Some of the algorithms needed to find
	bugs require in the worst case exponential time.</p>

	<p>The Clang Static Analyzer runs in a reasonable amount of time by both
	bounding the amount of checking work it will do as well as using clever
	algorithms to reduce the amount of work it must do to find bugs.</p></li>

	<h3>False Positives</h3>

	<p>Static analysis is not perfect. It can falsely flag bugs in a program where
	the code behaves correctly. Because some code checks require more analysis
	precision than others, the frequency of false positives can vary widely between
	different checks. Our long-term goal is to have the analyzer have a low false
	positive rate for most code on all checks.</p>

	<p>Please help us in this endeavor by <a href="filing_bugs.html">reporting false
	positives</a>. False positives cannot be addressed unless we know about
	them.</p>

	<h3>More Checks</h3>

	<p>Static analysis is not magic; a static analyzer can only find bugs that it
	has been specifically engineered to find. If there are specific kinds of bugs
	you would like the Clang Static Analyzer to find, please feel free to
	file <a href="filing_bugs.html">feature requests</a> or contribute your own
	patches.</p>

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	</body>
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