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15<h1>How To Setup Clang Tooling For LLVM</h1>
16<p>Clang Tooling provides infrastructure to write tools that need syntactic and
17semantic infomation about a program. This term also relates to a set of specific
18tools using this infrastructure (e.g. <code>clang-check</code>). This document
19provides information on how to set up and use Clang Tooling for the LLVM source
20code.</p>
21
22
23<!-- ======================================================================= -->
24<h2><a name="introduction">Introduction</a></h2>
25<!-- ======================================================================= -->
26
27<p>Clang Tooling needs a compilation database to figure out specific build
28options for each file. Currently it can create a compilation database from the
29<code>compilation_commands.json</code> file, generated by CMake. When invoking
30clang tools, you can either specify a path to a build directory using a command
31line parameter <code>-p</code> or let Clang Tooling find this file in your
32source tree. In either case you need to configure your build using CMake to use
33clang tools.</p>
34
35<!-- ======================================================================= -->
36<h2><a name="using-make">Setup Clang Tooling Using CMake and Make</a></h2>
37<!-- ======================================================================= -->
38
39<p>If you intend to use make to build LLVM, you should have CMake 2.8.6 or later
40installed (can be found <a href="http://cmake.org">here</a>).</p>
41<p>First, you need to generate Makefiles for LLVM with CMake. You need to make
42a build directory and run CMake from it:</p>
43<pre>
44 mkdir your/build/directory
45 cd your/build/directory
46 cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON path/to/llvm/sources
47</pre>
48
49<p>If you want to use clang instead of GCC, you can add
50<code>-DCMAKE_C_COMPILER=/path/to/clang
51 -DCMAKE_CXX_COMPILER=/path/to/clang++</code>.
52You can also use ccmake, which provides a curses interface to configure CMake
53variables for lazy people.</p>
54
55<p>As a result, the new <code>compile_commands.json</code> file should appear in
56the current directory. You should link it to the LLVM source tree so that Clang
57Tooling is able to use it:</p>
58<pre>
59 ln -s $PWD/compile_commands.json path/to/llvm/source/
60</pre>
61
62<p>Now you are ready to build and test LLVM using make:</p>
63<pre>
64 make check-all
65</pre>
66
67<!-- ======================================================================= -->
68<h2><a name="using-tools">Using Clang Tools</a></h2>
69<!-- ======================================================================= -->
70
71<p>After you completed the previous steps, you are ready to run clang tools. If
72you have a recent clang installed, you should have <code>clang-check</code> in
73$PATH. Try to run it on any .cpp file inside the LLVM source tree:</p>
74<pre>
75 clang-check tools/clang/lib/Tooling/CompilationDatabase.cpp
76</pre>
77<p>If you're using vim, it's convenient to have clang-check integrated. Put this
78into your .vimrc:</p>
79<pre>
Alexander Kornienko3d35a542012-09-05 12:11:13 +0000[diff] [blame]80function! ClangCheckImpl(cmd)
81 if &amp;autowrite | wall | endif
82 echo "Running " . a:cmd . " ..."
83 let l:output = system(a:cmd)
84 cexpr l:output
85 cwindow
86 let w:quickfix_title = a:cmd
87 if v:shell_error != 0
88 cc
89 endif
90 let g:clang_check_last_cmd = a:cmd
91endfunction
92
93function! ClangCheck()
94 let l:filename = expand('%')
95 if l:filename =~ '\.\(cpp\|cxx\|cc\|c\)$'
96 call ClangCheckImpl("clang-check " . l:filename)
97 elseif exists("g:clang_check_last_cmd")
98 call ClangCheckImpl(g:clang_check_last_cmd)
99 else
100 echo "Can't detect file's compilation arguments and no previous clang-check invocation!"
101 endif
102endfunction
103
104nmap &lt;silent&gt; &lt;F5&gt; :call ClangCheck()&lt;CR&gt;&lt;CR&gt;
Alexander Kornienkoa7f2c562012-07-11 14:27:44 +0000[diff] [blame]105</pre>
106
Alexander Kornienko3d35a542012-09-05 12:11:13 +0000[diff] [blame]107<p>When editing a .cpp/.cxx/.cc/.c file, hit F5 to reparse the file. In case
108the current file has a different extension (for example, .h), F5 will re-run
109the last clang-check invocation made from this vim instance (if any). The
110output will go into the error window, which is opened automatically when
111clang-check finds errors, and can be re-opened with <code>:cope</code>.</p>
Alexander Kornienkoa7f2c562012-07-11 14:27:44 +0000[diff] [blame]112
Alexander Kornienko5d46db82012-08-14 08:31:51 +0000[diff] [blame]113<p>Other <code>clang-check</code> options that can be useful when working with
114clang AST:</p>
115<ul>
116 <li><code>-ast-print</code> - Build ASTs and then pretty-print them.</li>
117 <li><code>-ast-dump</code> - Build ASTs and then debug dump them.</li>
118 <li><code>-ast-dump-filter=&lt;string&gt;</code> - Use with
119 <code>-ast-dump</code> or <code>-ast-print</code> to dump/print
120 only AST declaration nodes having a certain substring in a qualified name.
121 Use <code>-ast-list</code> to list all filterable declaration node
122 names.</li>
123 <li><code>-ast-list</code> - Build ASTs and print the list of declaration
124 node qualified names.</li>
125</ul>
126<p>Examples:</p>
127<pre>
128<b>$ clang-check tools/clang/tools/clang-check/ClangCheck.cpp -ast-dump -ast-dump-filter ActionFactory::newASTConsumer</b>
129Processing: tools/clang/tools/clang-check/ClangCheck.cpp.
130Dumping <anonymous namespace>::ActionFactory::newASTConsumer:
131clang::ASTConsumer *newASTConsumer() (CompoundStmt 0x44da290 &lt;/home/alexfh/local/llvm/tools/clang/tools/clang-check/ClangCheck.cpp:64:40, line:72:3&gt;
132 (IfStmt 0x44d97c8 &lt;line:65:5, line:66:45&gt;
133 &lt;&lt;&lt;NULL&gt;&gt;&gt;
134 (ImplicitCastExpr 0x44d96d0 &lt;line:65:9&gt; '_Bool':'_Bool' &lt;UserDefinedConversion&gt;
135...
136<b>$ clang-check tools/clang/tools/clang-check/ClangCheck.cpp -ast-print -ast-dump-filter ActionFactory::newASTConsumer</b>
137Processing: tools/clang/tools/clang-check/ClangCheck.cpp.
138Printing &lt;anonymous namespace&gt;::ActionFactory::newASTConsumer:
139clang::ASTConsumer *newASTConsumer() {
140 if (this-&gt;ASTList.operator _Bool())
141 return clang::CreateASTDeclNodeLister();
142 if (this-&gt;ASTDump.operator _Bool())
143 return clang::CreateASTDumper(this-&gt;ASTDumpFilter);
144 if (this-&gt;ASTPrint.operator _Bool())
145 return clang::CreateASTPrinter(&amp;llvm::outs(), this-&gt;ASTDumpFilter);
146 return new clang::ASTConsumer();
147}
148</pre>
Alexander Kornienkoa7f2c562012-07-11 14:27:44 +0000[diff] [blame]149
150<!-- ======================================================================= -->
151<h2><a name="using-ninja">(Experimental) Using Ninja Build System</a></h2>
152<!-- ======================================================================= -->
153
154<p>Optionally you can use the <a
155 href="https://github.com/martine/ninja">Ninja</a> build system instead of
156make. It is aimed at making your builds faster. Currently this step will require
157building Ninja from sources and using a development version of CMake.</p>
158<p>To take advantage of using Clang Tools along with Ninja build you need at
159least CMake 2.8.9. At the moment CMake 2.8.9 is still under development, so you
160can get latest development sources and build it yourself:</p>
161<pre>
162 git clone git://cmake.org/cmake.git
163 cd cmake
164 ./bootstrap
165 make
166 sudo make install
167</pre>
168
169<p>Having the correct version of CMake, you can clone the Ninja git repository
170and build Ninja from sources:</p>
171<pre>
172 git clone git://github.com/martine/ninja.git
173 cd ninja/
174 ./bootstrap.py
175</pre>
176<p>This will result in a single binary <code>ninja</code> in the current
177directory. It doesn't require installation and can just be copied to any
178location inside <code>$PATH</code>, say <code>/usr/local/bin/</code>:</p>
179<pre>
180 sudo cp ninja /usr/local/bin/
181 sudo chmod a+rx /usr/local/bin/ninja
182</pre>
183<p>After doing all of this, you'll need to generate Ninja build files for LLVM
184with CMake. You need to make a build directory and run CMake from it:</p>
185<pre>
186 mkdir your/build/directory
187 cd your/build/directory
188 cmake -G Ninja -DCMAKE_EXPORT_COMPILE_COMMANDS=ON path/to/llvm/sources
189</pre>
190
191<p>If you want to use clang instead of GCC, you can add
192<code>-DCMAKE_C_COMPILER=/path/to/clang
193 -DCMAKE_CXX_COMPILER=/path/to/clang++</code>.
194You can also use ccmake, which provides a curses interface to configure CMake
195variables in an interactive manner.</p>
196
197<p>As a result, the new <code>compile_commands.json</code> file should appear in
198the current directory. You should link it to the LLVM source tree so that Clang
199Tooling is able to use it:</p>
200<pre>
201 ln -s $PWD/compile_commands.json path/to/llvm/source/
202</pre>
203
204<p>Now you are ready to build and test LLVM using Ninja:</p>
205<pre>
206 ninja check-all
207</pre>
208<p>Other target names can be used in the same way as with make.</p>
209</div>
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