1*f4a2713aSLionel Sambuc<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" 2*f4a2713aSLionel Sambuc "http://www.w3.org/TR/html4/strict.dtd"> 3*f4a2713aSLionel Sambuc<!-- Material used from: HTML 4.01 specs: http://www.w3.org/TR/html401/ --> 4*f4a2713aSLionel Sambuc<html> 5*f4a2713aSLionel Sambuc<head> 6*f4a2713aSLionel Sambuc <META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> 7*f4a2713aSLionel Sambuc <title>Hacking on clang</title> 8*f4a2713aSLionel Sambuc <link type="text/css" rel="stylesheet" href="menu.css"> 9*f4a2713aSLionel Sambuc <link type="text/css" rel="stylesheet" href="content.css"> 10*f4a2713aSLionel Sambuc <style type="text/css"> 11*f4a2713aSLionel Sambuc pre { margin-left: 1.5em; } 12*f4a2713aSLionel Sambuc </style> 13*f4a2713aSLionel Sambuc</head> 14*f4a2713aSLionel Sambuc<body> 15*f4a2713aSLionel Sambuc<!--#include virtual="menu.html.incl"--> 16*f4a2713aSLionel Sambuc<div id="content"> 17*f4a2713aSLionel Sambuc <!--*********************************************************************--> 18*f4a2713aSLionel Sambuc <h1>Hacking on Clang</h1> 19*f4a2713aSLionel Sambuc <!--*********************************************************************--> 20*f4a2713aSLionel Sambuc 21*f4a2713aSLionel Sambuc <p>This document provides some hints for how to get started hacking 22*f4a2713aSLionel Sambuc on Clang for developers who are new to the Clang and/or LLVM 23*f4a2713aSLionel Sambuc codebases.</p> 24*f4a2713aSLionel Sambuc <ul> 25*f4a2713aSLionel Sambuc <li><a href="#style">Coding Standards</a></li> 26*f4a2713aSLionel Sambuc <li><a href="#docs">Developer Documentation</a></li> 27*f4a2713aSLionel Sambuc <li><a href="#debugging">Debugging</a></li> 28*f4a2713aSLionel Sambuc <li><a href="#testing">Testing</a> 29*f4a2713aSLionel Sambuc <ul> 30*f4a2713aSLionel Sambuc <li><a href="#testingNonWindows">Testing on Unix-like Systems</a></li> 31*f4a2713aSLionel Sambuc <li><a href="#testingWindows">Testing using Visual Studio on Windows</a></li> 32*f4a2713aSLionel Sambuc <li><a href="#testingCommands">Testing on the Command Line</a></li> 33*f4a2713aSLionel Sambuc </ul> 34*f4a2713aSLionel Sambuc </li> 35*f4a2713aSLionel Sambuc <li><a href="#patches">Creating Patch Files</a></li> 36*f4a2713aSLionel Sambuc <li><a href="#irgen">LLVM IR Generation</a></li> 37*f4a2713aSLionel Sambuc </ul> 38*f4a2713aSLionel Sambuc 39*f4a2713aSLionel Sambuc <!--=====================================================================--> 40*f4a2713aSLionel Sambuc <h2 id="style">Coding Standards</h2> 41*f4a2713aSLionel Sambuc <!--=====================================================================--> 42*f4a2713aSLionel Sambuc 43*f4a2713aSLionel Sambuc <p>Clang follows the 44*f4a2713aSLionel Sambuc LLVM <a href="http://llvm.org/docs/CodingStandards.html">Coding 45*f4a2713aSLionel Sambuc Standards</a>. When submitting patches, please take care to follow these standards 46*f4a2713aSLionel Sambuc and to match the style of the code to that present in Clang (for example, in 47*f4a2713aSLionel Sambuc terms of indentation, bracing, and statement spacing).</p> 48*f4a2713aSLionel Sambuc 49*f4a2713aSLionel Sambuc <p>Clang has a few additional coding standards:</p> 50*f4a2713aSLionel Sambuc <ul> 51*f4a2713aSLionel Sambuc <li><i>cstdio is forbidden</i>: library code should not output diagnostics 52*f4a2713aSLionel Sambuc or other information using <tt>cstdio</tt>; debugging routines should 53*f4a2713aSLionel Sambuc use <tt>llvm::errs()</tt>. Other uses of <tt>cstdio</tt> impose behavior 54*f4a2713aSLionel Sambuc upon clients and block integrating Clang as a library. Libraries should 55*f4a2713aSLionel Sambuc support <tt>raw_ostream</tt> based interfaces for textual 56*f4a2713aSLionel Sambuc output. See <a href="http://llvm.org/docs/CodingStandards.html#ll_raw_ostream">Coding 57*f4a2713aSLionel Sambuc Standards</a>.</li> 58*f4a2713aSLionel Sambuc </ul> 59*f4a2713aSLionel Sambuc 60*f4a2713aSLionel Sambuc <!--=====================================================================--> 61*f4a2713aSLionel Sambuc <h2 id="docs">Developer Documentation</h2> 62*f4a2713aSLionel Sambuc <!--=====================================================================--> 63*f4a2713aSLionel Sambuc 64*f4a2713aSLionel Sambuc <p>Both Clang and LLVM use doxygen to provide API documentation. Their 65*f4a2713aSLionel Sambuc respective web pages (generated nightly) are here:</p> 66*f4a2713aSLionel Sambuc <ul> 67*f4a2713aSLionel Sambuc <li><a href="http://clang.llvm.org/doxygen">Clang</a></li> 68*f4a2713aSLionel Sambuc <li><a href="http://llvm.org/doxygen">LLVM</a></li> 69*f4a2713aSLionel Sambuc </ul> 70*f4a2713aSLionel Sambuc 71*f4a2713aSLionel Sambuc <p>For work on the LLVM IR generation, the LLVM assembly language 72*f4a2713aSLionel Sambuc <a href="http://llvm.org/docs/LangRef.html">reference manual</a> is 73*f4a2713aSLionel Sambuc also useful.</p> 74*f4a2713aSLionel Sambuc 75*f4a2713aSLionel Sambuc <!--=====================================================================--> 76*f4a2713aSLionel Sambuc <h2 id="debugging">Debugging</h2> 77*f4a2713aSLionel Sambuc <!--=====================================================================--> 78*f4a2713aSLionel Sambuc 79*f4a2713aSLionel Sambuc <p>Inspecting data structures in a debugger:</p> 80*f4a2713aSLionel Sambuc <ul> 81*f4a2713aSLionel Sambuc <li>Many LLVM and Clang data structures provide 82*f4a2713aSLionel Sambuc a <tt>dump()</tt> method which will print a description of the 83*f4a2713aSLionel Sambuc data structure to <tt>stderr</tt>.</li> 84*f4a2713aSLionel Sambuc <li>The <a href="docs/InternalsManual.html#QualType"><tt>QualType</tt></a> 85*f4a2713aSLionel Sambuc structure is used pervasively. This is a simple value class for 86*f4a2713aSLionel Sambuc wrapping types with qualifiers; you can use 87*f4a2713aSLionel Sambuc the <tt>isConstQualified()</tt>, for example, to get one of the 88*f4a2713aSLionel Sambuc qualifiers, and the <tt>getTypePtr()</tt> method to get the 89*f4a2713aSLionel Sambuc wrapped <tt>Type*</tt> which you can then dump.</li> 90*f4a2713aSLionel Sambuc <li>For <a href="http://lldb.llvm.org"> <tt>LLDB</tt></a> users there are 91*f4a2713aSLionel Sambuc data formatters for clang data structures in 92*f4a2713aSLionel Sambuc <a href="http://llvm.org/svn/llvm-project/cfe/trunk/utils/ClangDataFormat.py"> 93*f4a2713aSLionel Sambuc <tt>utils/ClangDataFormat.py</tt></a>.</li> 94*f4a2713aSLionel Sambuc </ul> 95*f4a2713aSLionel Sambuc 96*f4a2713aSLionel Sambuc <!--=====================================================================--> 97*f4a2713aSLionel Sambuc <h3 id="debuggingVisualStudio">Debugging using Visual Studio</h3> 98*f4a2713aSLionel Sambuc <!--=====================================================================--> 99*f4a2713aSLionel Sambuc 100*f4a2713aSLionel Sambuc <p>The file <tt>utils/clangVisualizers.txt</tt> provides debugger visualizers that make debugging 101*f4a2713aSLionel Sambuc of more complex data types much easier.</p> 102*f4a2713aSLionel Sambuc <p>There are two ways to install them:</p> 103*f4a2713aSLionel Sambuc 104*f4a2713aSLionel Sambuc <ul> 105*f4a2713aSLionel Sambuc <li>Put the path to <tt>clangVisualizers.txt</tt> in the environment variable called 106*f4a2713aSLionel Sambuc <tt>_vcee_autoexp</tt>. This method should work for Visual Studio 2008 and above. 107*f4a2713aSLionel Sambuc </li> 108*f4a2713aSLionel Sambuc <li>Edit your local <tt>autoexp.dat</tt> (make sure you make a backup first!), 109*f4a2713aSLionel Sambuc located in <tt>Visual Studio Directory\Common7\Packages\Debugger</tt> and append 110*f4a2713aSLionel Sambuc the contents of <tt>clangVisuailzers.txt</tt> to it. This method should work for 111*f4a2713aSLionel Sambuc Visual Studio 2008 and above. 112*f4a2713aSLionel Sambuc </li> 113*f4a2713aSLionel Sambuc </ul> 114*f4a2713aSLionel Sambuc 115*f4a2713aSLionel Sambuc <p><i>[Note: To disable the visualizer for any specific variable, type 116*f4a2713aSLionel Sambuc <tt>variable_name,!</tt> inside the watch window.]</i></p> 117*f4a2713aSLionel Sambuc 118*f4a2713aSLionel Sambuc <!--=====================================================================--> 119*f4a2713aSLionel Sambuc <h2 id="testing">Testing</h2> 120*f4a2713aSLionel Sambuc <!--=====================================================================--> 121*f4a2713aSLionel Sambuc 122*f4a2713aSLionel Sambuc <p><i>[Note: The test running mechanism is currently under revision, so the 123*f4a2713aSLionel Sambuc following might change shortly.]</i></p> 124*f4a2713aSLionel Sambuc 125*f4a2713aSLionel Sambuc <!--=====================================================================--> 126*f4a2713aSLionel Sambuc <h3 id="testingNonWindows">Testing on Unix-like Systems</h3> 127*f4a2713aSLionel Sambuc <!--=====================================================================--> 128*f4a2713aSLionel Sambuc 129*f4a2713aSLionel Sambuc <p>Clang includes a basic regression suite in the tree which can be 130*f4a2713aSLionel Sambuc run with <tt>make test</tt> from the top-level clang directory, or 131*f4a2713aSLionel Sambuc just <tt>make</tt> in the <em>test</em> sub-directory. 132*f4a2713aSLionel Sambuc <tt>make VERBOSE=1</tt> can be used to show more detail 133*f4a2713aSLionel Sambuc about what is being run.</p> 134*f4a2713aSLionel Sambuc 135*f4a2713aSLionel Sambuc <p>If you built LLVM and Clang using CMake, the test suite can be run 136*f4a2713aSLionel Sambuc with <tt>make clang-test</tt> from the top-level LLVM directory.</p> 137*f4a2713aSLionel Sambuc 138*f4a2713aSLionel Sambuc <p>The tests primarily consist of a test runner script running the compiler 139*f4a2713aSLionel Sambuc under test on individual test files grouped in the directories under the 140*f4a2713aSLionel Sambuc test directory. The individual test files include comments at the 141*f4a2713aSLionel Sambuc beginning indicating the Clang compile options to use, to be read 142*f4a2713aSLionel Sambuc by the test runner. Embedded comments also can do things like telling 143*f4a2713aSLionel Sambuc the test runner that an error is expected at the current line. 144*f4a2713aSLionel Sambuc Any output files produced by the test will be placed under 145*f4a2713aSLionel Sambuc a created Output directory.</p> 146*f4a2713aSLionel Sambuc 147*f4a2713aSLionel Sambuc <p>During the run of <tt>make test</tt>, the terminal output will 148*f4a2713aSLionel Sambuc display a line similar to the following:</p> 149*f4a2713aSLionel Sambuc 150*f4a2713aSLionel Sambuc <pre>--- Running clang tests for i686-pc-linux-gnu ---</pre> 151*f4a2713aSLionel Sambuc 152*f4a2713aSLionel Sambuc <p>followed by a line continually overwritten with the current test 153*f4a2713aSLionel Sambuc file being compiled, and an overall completion percentage.</p> 154*f4a2713aSLionel Sambuc 155*f4a2713aSLionel Sambuc <p>After the <tt>make test</tt> run completes, the absence of any 156*f4a2713aSLionel Sambuc <tt>Failing Tests (count):</tt> message indicates that no tests 157*f4a2713aSLionel Sambuc failed unexpectedly. If any tests did fail, the 158*f4a2713aSLionel Sambuc <tt>Failing Tests (count):</tt> message will be followed by a list 159*f4a2713aSLionel Sambuc of the test source file paths that failed. For example:</p> 160*f4a2713aSLionel Sambuc 161*f4a2713aSLionel Sambuc <pre> 162*f4a2713aSLionel Sambuc Failing Tests (3): 163*f4a2713aSLionel Sambuc /home/john/llvm/tools/clang/test/SemaCXX/member-name-lookup.cpp 164*f4a2713aSLionel Sambuc /home/john/llvm/tools/clang/test/SemaCXX/namespace-alias.cpp 165*f4a2713aSLionel Sambuc /home/john/llvm/tools/clang/test/SemaCXX/using-directive.cpp 166*f4a2713aSLionel Sambuc</pre> 167*f4a2713aSLionel Sambuc 168*f4a2713aSLionel Sambuc <p>If you used the <tt>make VERBOSE=1</tt> option, the terminal 169*f4a2713aSLionel Sambuc output will reflect the error messages from the compiler and 170*f4a2713aSLionel Sambuc test runner.</p> 171*f4a2713aSLionel Sambuc 172*f4a2713aSLionel Sambuc <p>The regression suite can also be run with Valgrind by running 173*f4a2713aSLionel Sambuc <tt>make test VG=1</tt> in the top-level clang directory.</p> 174*f4a2713aSLionel Sambuc 175*f4a2713aSLionel Sambuc <p>For more intensive changes, running 176*f4a2713aSLionel Sambuc the <a href="http://llvm.org/docs/TestingGuide.html#testsuiterun">LLVM 177*f4a2713aSLionel Sambuc Test Suite</a> with clang is recommended. Currently the best way to 178*f4a2713aSLionel Sambuc override LLVMGCC, as in: <tt>make LLVMGCC="clang -std=gnu89" 179*f4a2713aSLionel Sambuc TEST=nightly report</tt> (make sure <tt>clang</tt> is in your PATH or use the 180*f4a2713aSLionel Sambuc full path).</p> 181*f4a2713aSLionel Sambuc 182*f4a2713aSLionel Sambuc <!--=====================================================================--> 183*f4a2713aSLionel Sambuc <h3 id="testingWindows">Testing using Visual Studio on Windows</h3> 184*f4a2713aSLionel Sambuc <!--=====================================================================--> 185*f4a2713aSLionel Sambuc 186*f4a2713aSLionel Sambuc <p>The Clang test suite can be run from either Visual Studio or 187*f4a2713aSLionel Sambuc the command line.</p> 188*f4a2713aSLionel Sambuc 189*f4a2713aSLionel Sambuc <p>Note that the test runner is based on 190*f4a2713aSLionel Sambuc Python, which must be installed. Find Python at: 191*f4a2713aSLionel Sambuc <a href="http://www.python.org/download/">http://www.python.org/download/</a>. 192*f4a2713aSLionel Sambuc Download the latest stable version (2.6.2 at the time of this writing).</p> 193*f4a2713aSLionel Sambuc 194*f4a2713aSLionel Sambuc <p>The GnuWin32 tools are also necessary for running the tests. 195*f4a2713aSLionel Sambuc Get them from <a href="http://getgnuwin32.sourceforge.net/"> 196*f4a2713aSLionel Sambuc http://getgnuwin32.sourceforge.net/</a>. 197*f4a2713aSLionel Sambuc If the environment variable <tt>%PATH%</tt> does not have GnuWin32, 198*f4a2713aSLionel Sambuc or if other grep(s) supercedes GnuWin32 on <tt>%PATH%,</tt> 199*f4a2713aSLionel Sambuc you should specify <tt>LLVM_LIT_TOOLS_DIR</tt> 200*f4a2713aSLionel Sambuc to CMake explicitly.</p> 201*f4a2713aSLionel Sambuc 202*f4a2713aSLionel Sambuc <p>The cmake build tool is set up to create Visual Studio project files 203*f4a2713aSLionel Sambuc for running the tests, "clang-test" being the root. Therefore, to 204*f4a2713aSLionel Sambuc run the test from Visual Studio, right-click the clang-test project 205*f4a2713aSLionel Sambuc and select "Build".</p> 206*f4a2713aSLionel Sambuc 207*f4a2713aSLionel Sambuc <p> 208*f4a2713aSLionel Sambuc Please see also 209*f4a2713aSLionel Sambuc <a href="http://llvm.org/docs/GettingStartedVS.html">Getting Started 210*f4a2713aSLionel Sambuc with the LLVM System using Microsoft Visual Studio</a> and 211*f4a2713aSLionel Sambuc <a href="http://llvm.org/docs/CMake.html">Building LLVM with CMake</a>. 212*f4a2713aSLionel Sambuc </p> 213*f4a2713aSLionel Sambuc 214*f4a2713aSLionel Sambuc <!--=====================================================================--> 215*f4a2713aSLionel Sambuc <h3 id="testingCommands">Testing on the Command Line</h3> 216*f4a2713aSLionel Sambuc <!--=====================================================================--> 217*f4a2713aSLionel Sambuc 218*f4a2713aSLionel Sambuc <p>If you want more control over how the tests are run, it may 219*f4a2713aSLionel Sambuc be convenient to run the test harness on the command-line directly. Before 220*f4a2713aSLionel Sambuc running tests from the command line, you will need to ensure that 221*f4a2713aSLionel Sambuc <tt>lit.site.cfg</tt> files have been created for your build. You can do 222*f4a2713aSLionel Sambuc this by running the tests as described in the previous sections. Once the 223*f4a2713aSLionel Sambuc tests have started running, you can stop them with control+C, as the 224*f4a2713aSLionel Sambuc files are generated before running any tests.</p> 225*f4a2713aSLionel Sambuc 226*f4a2713aSLionel Sambuc <p>Once that is done, to run all the tests from the command line, 227*f4a2713aSLionel Sambuc execute a command like the following:</p> 228*f4a2713aSLionel Sambuc 229*f4a2713aSLionel Sambuc <pre> 230*f4a2713aSLionel Sambuc python (path to llvm)\llvm\utils\lit\lit.py -sv 231*f4a2713aSLionel Sambuc --param=build_mode=Win32 --param=build_config=Debug 232*f4a2713aSLionel Sambuc --param=clang_site_config=(build dir)\tools\clang\test\lit.site.cfg 233*f4a2713aSLionel Sambuc (path to llvm)\llvm\tools\clang\test 234*f4a2713aSLionel Sambuc</pre> 235*f4a2713aSLionel Sambuc 236*f4a2713aSLionel Sambuc <p>For CMake builds e.g. on Windows with Visual Studio, you will need 237*f4a2713aSLionel Sambuc to specify your build configuration (Debug, Release, etc.) via 238*f4a2713aSLionel Sambuc <tt>--param=build_config=(build config)</tt>. You may also need to specify 239*f4a2713aSLionel Sambuc the build mode (Win32, etc) via <tt>--param=build_mode=(build mode)</tt>.</p> 240*f4a2713aSLionel Sambuc 241*f4a2713aSLionel Sambuc <p>Additionally, you will need to specify the lit site configuration which 242*f4a2713aSLionel Sambuc lives in (build dir)\tools\clang\test, via 243*f4a2713aSLionel Sambuc <tt>--param=clang_site_config=(build dir)\tools\clang\test\lit.site.cfg</tt>. 244*f4a2713aSLionel Sambuc </p> 245*f4a2713aSLionel Sambuc 246*f4a2713aSLionel Sambuc <p>To run a single test:</p> 247*f4a2713aSLionel Sambuc 248*f4a2713aSLionel Sambuc <pre> 249*f4a2713aSLionel Sambuc python (path to llvm)\llvm\utils\lit\lit.py -sv 250*f4a2713aSLionel Sambuc --param=build_mode=Win32 --param=build_config=Debug 251*f4a2713aSLionel Sambuc --param=clang_site_config=(build dir)\tools\clang\test\lit.site.cfg 252*f4a2713aSLionel Sambuc (path to llvm)\llvm\tools\clang\test\(dir)\(test) 253*f4a2713aSLionel Sambuc</pre> 254*f4a2713aSLionel Sambuc 255*f4a2713aSLionel Sambuc <p>For example:</p> 256*f4a2713aSLionel Sambuc 257*f4a2713aSLionel Sambuc <pre> 258*f4a2713aSLionel Sambuc python C:\Tool\llvm\utils\lit\lit.py -sv 259*f4a2713aSLionel Sambuc --param=build_mode=Win32 --param=build_config=Debug 260*f4a2713aSLionel Sambuc --param=clang_site_config=c:\Tools\build\tools\clang\test\lit.site.cfg 261*f4a2713aSLionel Sambuc C:\Tools\llvm\tools\clang\test\Sema\wchar.c 262*f4a2713aSLionel Sambuc</pre> 263*f4a2713aSLionel Sambuc 264*f4a2713aSLionel Sambuc <p>The -sv option above tells the runner to show the test output if 265*f4a2713aSLionel Sambuc any tests failed, to help you determine the cause of failure.</p> 266*f4a2713aSLionel Sambuc 267*f4a2713aSLionel Sambuc <p>You can also pass in the --no-progress-bar option if you wish to disable 268*f4a2713aSLionel Sambuc progress indications while the tests are running.</p> 269*f4a2713aSLionel Sambuc 270*f4a2713aSLionel Sambuc <p>Your output might look something like this:</p> 271*f4a2713aSLionel Sambuc 272*f4a2713aSLionel Sambuc <pre>lit.py: lit.cfg:152: note: using clang: 'C:\Tools\llvm\bin\Release\clang.EXE' 273*f4a2713aSLionel Sambuc-- Testing: Testing: 2534 tests, 4 threads -- 274*f4a2713aSLionel SambucTesting: 0 .. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.. 275*f4a2713aSLionel SambucTesting Time: 81.52s 276*f4a2713aSLionel Sambuc Expected Passes : 2503 277*f4a2713aSLionel Sambuc Expected Failures : 28 278*f4a2713aSLionel Sambuc Unsupported Tests : 3 279*f4a2713aSLionel Sambuc</pre> 280*f4a2713aSLionel Sambuc 281*f4a2713aSLionel Sambuc <p>The statistic, "Unexpected Failures" (not shown if all tests pass), is the important one.</p> 282*f4a2713aSLionel Sambuc 283*f4a2713aSLionel Sambuc <!--=====================================================================--> 284*f4a2713aSLionel Sambuc <h2 id="patches">Creating Patch Files</h2> 285*f4a2713aSLionel Sambuc <!--=====================================================================--> 286*f4a2713aSLionel Sambuc 287*f4a2713aSLionel Sambuc <p>To return changes to the Clang team, unless you have checkin 288*f4a2713aSLionel Sambuc privileges, the preferred way is to send patch files to the 289*f4a2713aSLionel Sambuc cfe-commits mailing list, with an explanation of what the patch is 290*f4a2713aSLionel Sambuc for. If your patch requires a wider discussion (for example, 291*f4a2713aSLionel Sambuc because it is an architectural change), you can use the cfe-dev 292*f4a2713aSLionel Sambuc mailing list. </p> 293*f4a2713aSLionel Sambuc 294*f4a2713aSLionel Sambuc <p>To create these patch files, change directory 295*f4a2713aSLionel Sambuc to the llvm/tools/clang root and run:</p> 296*f4a2713aSLionel Sambuc 297*f4a2713aSLionel Sambuc <pre>svn diff (relative path) >(patch file name)</pre> 298*f4a2713aSLionel Sambuc 299*f4a2713aSLionel Sambuc <p>For example, for getting the diffs of all of clang:</p> 300*f4a2713aSLionel Sambuc 301*f4a2713aSLionel Sambuc <pre>svn diff . >~/mypatchfile.patch</pre> 302*f4a2713aSLionel Sambuc 303*f4a2713aSLionel Sambuc <p>For example, for getting the diffs of a single file:</p> 304*f4a2713aSLionel Sambuc 305*f4a2713aSLionel Sambuc <pre>svn diff lib/Parse/ParseDeclCXX.cpp >~/ParseDeclCXX.patch</pre> 306*f4a2713aSLionel Sambuc 307*f4a2713aSLionel Sambuc <p>Note that the paths embedded in the patch depend on where you run it, 308*f4a2713aSLionel Sambuc so changing directory to the llvm/tools/clang directory is recommended.</p> 309*f4a2713aSLionel Sambuc 310*f4a2713aSLionel Sambuc <!--=====================================================================--> 311*f4a2713aSLionel Sambuc <h2 id="irgen">LLVM IR Generation</h2> 312*f4a2713aSLionel Sambuc <!--=====================================================================--> 313*f4a2713aSLionel Sambuc 314*f4a2713aSLionel Sambuc <p>The LLVM IR generation part of clang handles conversion of the 315*f4a2713aSLionel Sambuc AST nodes output by the Sema module to the LLVM Intermediate 316*f4a2713aSLionel Sambuc Representation (IR). Historically, this was referred to as 317*f4a2713aSLionel Sambuc "codegen", and the Clang code for this lives 318*f4a2713aSLionel Sambuc in <tt>lib/CodeGen</tt>.</p> 319*f4a2713aSLionel Sambuc 320*f4a2713aSLionel Sambuc <p>The output is most easily inspected using the <tt>-emit-llvm</tt> 321*f4a2713aSLionel Sambuc option to clang (possibly in conjunction with <tt>-o -</tt>). You 322*f4a2713aSLionel Sambuc can also use <tt>-emit-llvm-bc</tt> to write an LLVM bitcode file 323*f4a2713aSLionel Sambuc which can be processed by the suite of LLVM tools 324*f4a2713aSLionel Sambuc like <tt>llvm-dis</tt>, <tt>llvm-nm</tt>, etc. See the LLVM 325*f4a2713aSLionel Sambuc <a href="http://llvm.org/docs/CommandGuide/">Command Guide</a> 326*f4a2713aSLionel Sambuc for more information.</p> 327*f4a2713aSLionel Sambuc 328*f4a2713aSLionel Sambuc</div> 329*f4a2713aSLionel Sambuc</body> 330*f4a2713aSLionel Sambuc</html> 331