This patch implements an AST matching framework that allows to write tools that match on the C++ ASTs. The main interface is in ASTMatchers.h, an example implementation of a tool that removes redundant .c_str() calls is in the example RemoveCStrCalls.cpp (patch to llvm/clang produced by running this tool will be sent out shortly in an extra email).<br>
<br>Currently we have an in-language DSL that allows to write expressions such as (taken from the .c_str() example):<br><meta http-equiv="content-type" content="text/html; charset=utf-8"><span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif; font-size: 13px; "><table cellpadding="0" cellspacing="0" id="thecode" style="padding-top: 5px; padding-right: 5px; padding-bottom: 5px; padding-left: 5px; ">
<tbody><tr><td class="udiff udiffadd" id="newcode187" style="white-space: pre; font-family: monospace; font-size: 12px; vertical-align: top; ">ConstructorCall(
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HasDeclaration(Method(HasName(StringConstructor))),
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ArgumentCountIs(2),
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// The first argument must have the form x.c_str() or p->c_str()
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// where the method is string::c_str(). We can use the copy
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// constructor of string instead (or the compiler might share
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// the string object).
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HasArgument(
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0,
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Id("call", Call(
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Callee(Id("member", MemberExpression())),
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Callee(Method(HasName(StringCStrMethod))),
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On(Id("arg", Expression()))))),
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// The second argument is the alloc object which must not be
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// present explicitly.
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HasArgument(
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1,
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DefaultArgument()))</td></tr></tbody></table></span><div><font class="Apple-style-span" face="arial, helvetica, sans-serif"><br></font></div><div><font class="Apple-style-span" face="arial, helvetica, sans-serif">The next steps will be to build up better support for in-process refactorings based on the Rewriter, to build up higher-level matchers for common patterns, and to extend the low-level matcher library.</font></div>
<div><font class="Apple-style-span" face="arial, helvetica, sans-serif"><br></font></div><div><font class="Apple-style-span" face="arial, helvetica, sans-serif">(rietveld link: </font><a href="http://codereview.appspot.com/4552059/">http://codereview.appspot.com/4552059/</a>)</div>
<div><br></div><div>Cheers,</div><div>/Manuel</div><meta http-equiv="content-type" content="text/html; charset=utf-8">