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Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]7<title>Customizing LLVMC: Reference Manual</title>
Mikhail Glushenkov8cc82882008-12-13 17:50:58 +0000[diff] [blame]8<link rel="stylesheet" href="llvm.css" type="text/css" />
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10<body>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]11<div class="document" id="customizing-llvmc-reference-manual">
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]12<h1 class="title">Customizing LLVMC: Reference Manual</h1>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]13
Mikhail Glushenkov23f522a2008-12-13 17:51:47 +0000[diff] [blame]14<!-- This file was automatically generated by rst2html.
15Please do not edit directly!
16The ReST source lives in the directory 'tools/llvmc/doc'. -->
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]17<div class="contents topic" id="contents">
18<p class="topic-title first">Contents</p>
Mikhail Glushenkovd5652032008-12-13 02:28:58 +0000[diff] [blame]19<ul class="simple">
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]20<li><a class="reference internal" href="#introduction" id="id4">Introduction</a></li>
21<li><a class="reference internal" href="#compiling-with-llvmc" id="id5">Compiling with LLVMC</a></li>
22<li><a class="reference internal" href="#predefined-options" id="id6">Predefined options</a></li>
23<li><a class="reference internal" href="#compiling-llvmc-plugins" id="id7">Compiling LLVMC plugins</a></li>
24<li><a class="reference internal" href="#customizing-llvmc-the-compilation-graph" id="id8">Customizing LLVMC: the compilation graph</a></li>
25<li><a class="reference internal" href="#describing-options" id="id9">Describing options</a><ul>
26<li><a class="reference internal" href="#external-options" id="id10">External options</a></li>
Mikhail Glushenkovd5652032008-12-13 02:28:58 +0000[diff] [blame]27</ul>
28</li>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]29<li><a class="reference internal" href="#conditional-evaluation" id="id11">Conditional evaluation</a></li>
30<li><a class="reference internal" href="#writing-a-tool-description" id="id12">Writing a tool description</a><ul>
31<li><a class="reference internal" href="#actions" id="id13">Actions</a></li>
Mikhail Glushenkovd5652032008-12-13 02:28:58 +0000[diff] [blame]32</ul>
33</li>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]34<li><a class="reference internal" href="#language-map" id="id14">Language map</a></li>
35<li><a class="reference internal" href="#more-advanced-topics" id="id15">More advanced topics</a><ul>
36<li><a class="reference internal" href="#hooks-and-environment-variables" id="id16">Hooks and environment variables</a></li>
37<li><a class="reference internal" href="#how-plugins-are-loaded" id="id17">How plugins are loaded</a></li>
38<li><a class="reference internal" href="#debugging" id="id18">Debugging</a></li>
Mikhail Glushenkovd5652032008-12-13 02:28:58 +0000[diff] [blame]39</ul>
40</li>
41</ul>
42</div>
43<div class="doc_author">
44<p>Written by <a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a></p>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]45</div><div class="section" id="introduction">
46<h1><a class="toc-backref" href="#id4">Introduction</a></h1>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]47<p>LLVMC is a generic compiler driver, designed to be customizable and
48extensible. It plays the same role for LLVM as the <tt class="docutils literal"><span class="pre">gcc</span></tt> program
49does for GCC - LLVMC's job is essentially to transform a set of input
50files into a set of targets depending on configuration rules and user
51options. What makes LLVMC different is that these transformation rules
52are completely customizable - in fact, LLVMC knows nothing about the
53specifics of transformation (even the command-line options are mostly
54not hard-coded) and regards the transformation structure as an
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]55abstract graph. The structure of this graph is completely determined
56by plugins, which can be either statically or dynamically linked. This
57makes it possible to easily adapt LLVMC for other purposes - for
58example, as a build tool for game resources.</p>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]59<p>Because LLVMC employs <a class="reference external" href="http://llvm.cs.uiuc.edu/docs/TableGenFundamentals.html">TableGen</a> as its configuration language, you
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]60need to be familiar with it to customize LLVMC.</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]61</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]62<div class="section" id="compiling-with-llvmc">
63<h1><a class="toc-backref" href="#id5">Compiling with LLVMC</a></h1>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]64<p>LLVMC tries hard to be as compatible with <tt class="docutils literal"><span class="pre">gcc</span></tt> as possible,
65although there are some small differences. Most of the time, however,
66you shouldn't be able to notice them:</p>
67<pre class="literal-block">
68$ # This works as expected:
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]69$ llvmc -O3 -Wall hello.cpp
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]70$ ./a.out
71hello
72</pre>
73<p>One nice feature of LLVMC is that one doesn't have to distinguish
74between different compilers for different languages (think <tt class="docutils literal"><span class="pre">g++</span></tt> and
75<tt class="docutils literal"><span class="pre">gcc</span></tt>) - the right toolchain is chosen automatically based on input
76language names (which are, in turn, determined from file
77extensions). If you want to force files ending with &quot;.c&quot; to compile as
78C++, use the <tt class="docutils literal"><span class="pre">-x</span></tt> option, just like you would do it with <tt class="docutils literal"><span class="pre">gcc</span></tt>:</p>
79<pre class="literal-block">
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]80$ # hello.c is really a C++ file
81$ llvmc -x c++ hello.c
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]82$ ./a.out
83hello
84</pre>
85<p>On the other hand, when using LLVMC as a linker to combine several C++
86object files you should provide the <tt class="docutils literal"><span class="pre">--linker</span></tt> option since it's
87impossible for LLVMC to choose the right linker in that case:</p>
88<pre class="literal-block">
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]89$ llvmc -c hello.cpp
90$ llvmc hello.o
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]91[A lot of link-time errors skipped]
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]92$ llvmc --linker=c++ hello.o
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]93$ ./a.out
94hello
95</pre>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]96<p>By default, LLVMC uses <tt class="docutils literal"><span class="pre">llvm-gcc</span></tt> to compile the source code. It is
97also possible to choose the work-in-progress <tt class="docutils literal"><span class="pre">clang</span></tt> compiler with
98the <tt class="docutils literal"><span class="pre">-clang</span></tt> option.</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]99</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]100<div class="section" id="predefined-options">
101<h1><a class="toc-backref" href="#id6">Predefined options</a></h1>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]102<p>LLVMC has some built-in options that can't be overridden in the
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]103configuration libraries:</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]104<ul class="simple">
105<li><tt class="docutils literal"><span class="pre">-o</span> <span class="pre">FILE</span></tt> - Output file name.</li>
106<li><tt class="docutils literal"><span class="pre">-x</span> <span class="pre">LANGUAGE</span></tt> - Specify the language of the following input files
107until the next -x option.</li>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]108<li><tt class="docutils literal"><span class="pre">-load</span> <span class="pre">PLUGIN_NAME</span></tt> - Load the specified plugin DLL. Example:
109<tt class="docutils literal"><span class="pre">-load</span> <span class="pre">$LLVM_DIR/Release/lib/LLVMCSimple.so</span></tt>.</li>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]110<li><tt class="docutils literal"><span class="pre">-v</span></tt> - Enable verbose mode, i.e. print out all executed commands.</li>
Mikhail Glushenkov4ad0d572009-03-27 12:58:29 +0000[diff] [blame]111<li><tt class="docutils literal"><span class="pre">--check-graph</span></tt> - Check the compilation for common errors like mismatched
112output/input language names, multiple default edges and cycles. Because of
113plugins, these checks can't be performed at compile-time. Exit with code zero if
114no errors were found, and return the number of found errors otherwise. Hidden
115option, useful for debugging LLVMC plugins.</li>
116<li><tt class="docutils literal"><span class="pre">--view-graph</span></tt> - Show a graphical representation of the compilation graph
117and exit. Requires that you have <tt class="docutils literal"><span class="pre">dot</span></tt> and <tt class="docutils literal"><span class="pre">gv</span></tt> programs installed. Hidden
118option, useful for debugging LLVMC plugins.</li>
119<li><tt class="docutils literal"><span class="pre">--write-graph</span></tt> - Write a <tt class="docutils literal"><span class="pre">compilation-graph.dot</span></tt> file in the current
120directory with the compilation graph description in Graphviz format (identical
121to the file used by the <tt class="docutils literal"><span class="pre">--view-graph</span></tt> option). The <tt class="docutils literal"><span class="pre">-o</span></tt> option can be used
122to set the output file name. Hidden option, useful for debugging LLVMC plugins.</li>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]123<li><tt class="docutils literal"><span class="pre">--save-temps</span></tt> - Write temporary files to the current directory
124and do not delete them on exit. Hidden option, useful for debugging.</li>
125<li><tt class="docutils literal"><span class="pre">--help</span></tt>, <tt class="docutils literal"><span class="pre">--help-hidden</span></tt>, <tt class="docutils literal"><span class="pre">--version</span></tt> - These options have
126their standard meaning.</li>
127</ul>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]128</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]129<div class="section" id="compiling-llvmc-plugins">
130<h1><a class="toc-backref" href="#id7">Compiling LLVMC plugins</a></h1>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]131<p>It's easiest to start working on your own LLVMC plugin by copying the
132skeleton project which lives under <tt class="docutils literal"><span class="pre">$LLVMC_DIR/plugins/Simple</span></tt>:</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]133<pre class="literal-block">
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]134$ cd $LLVMC_DIR/plugins
135$ cp -r Simple MyPlugin
136$ cd MyPlugin
137$ ls
138Makefile PluginMain.cpp Simple.td
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]139</pre>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]140<p>As you can see, our basic plugin consists of only two files (not
141counting the build script). <tt class="docutils literal"><span class="pre">Simple.td</span></tt> contains TableGen
142description of the compilation graph; its format is documented in the
143following sections. <tt class="docutils literal"><span class="pre">PluginMain.cpp</span></tt> is just a helper file used to
144compile the auto-generated C++ code produced from TableGen source. It
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]145can also contain hook definitions (see <a class="reference internal" href="#hooks">below</a>).</p>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]146<p>The first thing that you should do is to change the <tt class="docutils literal"><span class="pre">LLVMC_PLUGIN</span></tt>
147variable in the <tt class="docutils literal"><span class="pre">Makefile</span></tt> to avoid conflicts (since this variable
148is used to name the resulting library):</p>
149<pre class="literal-block">
150LLVMC_PLUGIN=MyPlugin
151</pre>
152<p>It is also a good idea to rename <tt class="docutils literal"><span class="pre">Simple.td</span></tt> to something less
153generic:</p>
154<pre class="literal-block">
155$ mv Simple.td MyPlugin.td
156</pre>
157<p>Note that the plugin source directory must be placed under
158<tt class="docutils literal"><span class="pre">$LLVMC_DIR/plugins</span></tt> to make use of the existing build
159infrastructure. To build a version of the LLVMC executable called
160<tt class="docutils literal"><span class="pre">mydriver</span></tt> with your plugin compiled in, use the following command:</p>
161<pre class="literal-block">
162$ cd $LLVMC_DIR
163$ make BUILTIN_PLUGINS=MyPlugin DRIVER_NAME=mydriver
164</pre>
165<p>To build your plugin as a dynamic library, just <tt class="docutils literal"><span class="pre">cd</span></tt> to its source
166directory and run <tt class="docutils literal"><span class="pre">make</span></tt>. The resulting file will be called
167<tt class="docutils literal"><span class="pre">LLVMC$(LLVMC_PLUGIN).$(DLL_EXTENSION)</span></tt> (in our case,
168<tt class="docutils literal"><span class="pre">LLVMCMyPlugin.so</span></tt>). This library can be then loaded in with the
169<tt class="docutils literal"><span class="pre">-load</span></tt> option. Example:</p>
170<pre class="literal-block">
171$ cd $LLVMC_DIR/plugins/Simple
172$ make
173$ llvmc -load $LLVM_DIR/Release/lib/LLVMCSimple.so
174</pre>
175<p>Sometimes, you will want a 'bare-bones' version of LLVMC that has no
176built-in plugins. It can be compiled with the following command:</p>
177<pre class="literal-block">
178$ cd $LLVMC_DIR
179$ make BUILTIN_PLUGINS=&quot;&quot;
180</pre>
181</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]182<div class="section" id="customizing-llvmc-the-compilation-graph">
183<h1><a class="toc-backref" href="#id8">Customizing LLVMC: the compilation graph</a></h1>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]184<p>Each TableGen configuration file should include the common
185definitions:</p>
186<pre class="literal-block">
187include &quot;llvm/CompilerDriver/Common.td&quot;
188</pre>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]189<p>Internally, LLVMC stores information about possible source
190transformations in form of a graph. Nodes in this graph represent
191tools, and edges between two nodes represent a transformation path. A
192special &quot;root&quot; node is used to mark entry points for the
193transformations. LLVMC also assigns a weight to each edge (more on
194this later) to choose between several alternative edges.</p>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]195<p>The definition of the compilation graph (see file
196<tt class="docutils literal"><span class="pre">plugins/Base/Base.td</span></tt> for an example) is just a list of edges:</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]197<pre class="literal-block">
198def CompilationGraph : CompilationGraph&lt;[
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]199 Edge&lt;&quot;root&quot;, &quot;llvm_gcc_c&quot;&gt;,
200 Edge&lt;&quot;root&quot;, &quot;llvm_gcc_assembler&quot;&gt;,
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]201 ...
202
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]203 Edge&lt;&quot;llvm_gcc_c&quot;, &quot;llc&quot;&gt;,
204 Edge&lt;&quot;llvm_gcc_cpp&quot;, &quot;llc&quot;&gt;,
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]205 ...
206
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]207 OptionalEdge&lt;&quot;llvm_gcc_c&quot;, &quot;opt&quot;, (case (switch_on &quot;opt&quot;),
208 (inc_weight))&gt;,
209 OptionalEdge&lt;&quot;llvm_gcc_cpp&quot;, &quot;opt&quot;, (case (switch_on &quot;opt&quot;),
210 (inc_weight))&gt;,
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]211 ...
212
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]213 OptionalEdge&lt;&quot;llvm_gcc_assembler&quot;, &quot;llvm_gcc_cpp_linker&quot;,
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]214 (case (input_languages_contain &quot;c++&quot;), (inc_weight),
215 (or (parameter_equals &quot;linker&quot;, &quot;g++&quot;),
216 (parameter_equals &quot;linker&quot;, &quot;c++&quot;)), (inc_weight))&gt;,
217 ...
218
219 ]&gt;;
220</pre>
221<p>As you can see, the edges can be either default or optional, where
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]222optional edges are differentiated by an additional <tt class="docutils literal"><span class="pre">case</span></tt> expression
223used to calculate the weight of this edge. Notice also that we refer
224to tools via their names (as strings). This makes it possible to add
225edges to an existing compilation graph in plugins without having to
226know about all tool definitions used in the graph.</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]227<p>The default edges are assigned a weight of 1, and optional edges get a
228weight of 0 + 2*N where N is the number of tests that evaluated to
229true in the <tt class="docutils literal"><span class="pre">case</span></tt> expression. It is also possible to provide an
230integer parameter to <tt class="docutils literal"><span class="pre">inc_weight</span></tt> and <tt class="docutils literal"><span class="pre">dec_weight</span></tt> - in this case,
231the weight is increased (or decreased) by the provided value instead
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]232of the default 2. It is also possible to change the default weight of
233an optional edge by using the <tt class="docutils literal"><span class="pre">default</span></tt> clause of the <tt class="docutils literal"><span class="pre">case</span></tt>
234construct.</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]235<p>When passing an input file through the graph, LLVMC picks the edge
236with the maximum weight. To avoid ambiguity, there should be only one
237default edge between two nodes (with the exception of the root node,
238which gets a special treatment - there you are allowed to specify one
239default edge <em>per language</em>).</p>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]240<p>When multiple plugins are loaded, their compilation graphs are merged
241together. Since multiple edges that have the same end nodes are not
242allowed (i.e. the graph is not a multigraph), an edge defined in
243several plugins will be replaced by the definition from the plugin
244that was loaded last. Plugin load order can be controlled by using the
245plugin priority feature described above.</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]246<p>To get a visual representation of the compilation graph (useful for
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]247debugging), run <tt class="docutils literal"><span class="pre">llvmc</span> <span class="pre">--view-graph</span></tt>. You will need <tt class="docutils literal"><span class="pre">dot</span></tt> and
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]248<tt class="docutils literal"><span class="pre">gsview</span></tt> installed for this to work properly.</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]249</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]250<div class="section" id="describing-options">
251<h1><a class="toc-backref" href="#id9">Describing options</a></h1>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]252<p>Command-line options that the plugin supports are defined by using an
253<tt class="docutils literal"><span class="pre">OptionList</span></tt>:</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]254<pre class="literal-block">
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]255def Options : OptionList&lt;[
256(switch_option &quot;E&quot;, (help &quot;Help string&quot;)),
257(alias_option &quot;quiet&quot;, &quot;q&quot;)
258...
259]&gt;;
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]260</pre>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]261<p>As you can see, the option list is just a list of DAGs, where each DAG
262is an option description consisting of the option name and some
263properties. A plugin can define more than one option list (they are
264all merged together in the end), which can be handy if one wants to
265separate option groups syntactically.</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]266<ul>
267<li><p class="first">Possible option types:</p>
268<blockquote>
269<ul class="simple">
Mikhail Glushenkov5303c752009-01-28 03:47:38 +0000[diff] [blame]270<li><tt class="docutils literal"><span class="pre">switch_option</span></tt> - a simple boolean switch without arguments, for example
271<tt class="docutils literal"><span class="pre">-O2</span></tt> or <tt class="docutils literal"><span class="pre">-time</span></tt>. At most one occurrence is allowed.</li>
272<li><tt class="docutils literal"><span class="pre">parameter_option</span></tt> - option that takes one argument, for example
273<tt class="docutils literal"><span class="pre">-std=c99</span></tt>. It is also allowed to use spaces instead of the equality
274sign: <tt class="docutils literal"><span class="pre">-std</span> <span class="pre">c99</span></tt>. At most one occurrence is allowed.</li>
275<li><tt class="docutils literal"><span class="pre">parameter_list_option</span></tt> - same as the above, but more than one option
276occurence is allowed.</li>
277<li><tt class="docutils literal"><span class="pre">prefix_option</span></tt> - same as the parameter_option, but the option name and
278argument do not have to be separated. Example: <tt class="docutils literal"><span class="pre">-ofile</span></tt>. This can be also
279specified as <tt class="docutils literal"><span class="pre">-o</span> <span class="pre">file</span></tt>; however, <tt class="docutils literal"><span class="pre">-o=file</span></tt> will be parsed incorrectly
280(<tt class="docutils literal"><span class="pre">=file</span></tt> will be interpreted as option value). At most one occurrence is
281allowed.</li>
282<li><tt class="docutils literal"><span class="pre">prefix_list_option</span></tt> - same as the above, but more than one occurence of
283the option is allowed; example: <tt class="docutils literal"><span class="pre">-lm</span> <span class="pre">-lpthread</span></tt>.</li>
284<li><tt class="docutils literal"><span class="pre">alias_option</span></tt> - a special option type for creating aliases. Unlike other
285option types, aliases are not allowed to have any properties besides the
286aliased option name. Usage example: <tt class="docutils literal"><span class="pre">(alias_option</span> <span class="pre">&quot;preprocess&quot;,</span> <span class="pre">&quot;E&quot;)</span></tt></li>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]287</ul>
288</blockquote>
289</li>
290<li><p class="first">Possible option properties:</p>
291<blockquote>
292<ul class="simple">
Mikhail Glushenkov5303c752009-01-28 03:47:38 +0000[diff] [blame]293<li><tt class="docutils literal"><span class="pre">help</span></tt> - help string associated with this option. Used for <tt class="docutils literal"><span class="pre">--help</span></tt>
294output.</li>
295<li><tt class="docutils literal"><span class="pre">required</span></tt> - this option must be specified exactly once (or, in case of
296the list options without the <tt class="docutils literal"><span class="pre">multi_val</span></tt> property, at least
297once). Incompatible with <tt class="docutils literal"><span class="pre">zero_or_one</span></tt> and <tt class="docutils literal"><span class="pre">one_or_more</span></tt>.</li>
298<li><tt class="docutils literal"><span class="pre">one_or_more</span></tt> - the option must be specified at least one time. Useful
299only for list options in conjunction with <tt class="docutils literal"><span class="pre">multi_val</span></tt>; for ordinary lists
300it is synonymous with <tt class="docutils literal"><span class="pre">required</span></tt>. Incompatible with <tt class="docutils literal"><span class="pre">required</span></tt> and
301<tt class="docutils literal"><span class="pre">zero_or_one</span></tt>.</li>
302<li><tt class="docutils literal"><span class="pre">zero_or_one</span></tt> - the option can be specified zero or one times. Useful
303only for list options in conjunction with <tt class="docutils literal"><span class="pre">multi_val</span></tt>. Incompatible with
304<tt class="docutils literal"><span class="pre">required</span></tt> and <tt class="docutils literal"><span class="pre">one_or_more</span></tt>.</li>
Mikhail Glushenkovf9b1d792009-01-15 02:42:40 +0000[diff] [blame]305<li><tt class="docutils literal"><span class="pre">hidden</span></tt> - the description of this option will not appear in
306the <tt class="docutils literal"><span class="pre">--help</span></tt> output (but will appear in the <tt class="docutils literal"><span class="pre">--help-hidden</span></tt>
307output).</li>
308<li><tt class="docutils literal"><span class="pre">really_hidden</span></tt> - the option will not be mentioned in any help
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]309output.</li>
Mikhail Glushenkov5303c752009-01-28 03:47:38 +0000[diff] [blame]310<li><tt class="docutils literal"><span class="pre">multi_val</span> <span class="pre">n</span></tt> - this option takes <em>n</em> arguments (can be useful in some
311special cases). Usage example: <tt class="docutils literal"><span class="pre">(parameter_list_option</span> <span class="pre">&quot;foo&quot;,</span> <span class="pre">(multi_val</span>
312<span class="pre">3))</span></tt>. Only list options can have this attribute; you can, however, use
313the <tt class="docutils literal"><span class="pre">one_or_more</span></tt> and <tt class="docutils literal"><span class="pre">zero_or_one</span></tt> properties.</li>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]314<li><tt class="docutils literal"><span class="pre">extern</span></tt> - this option is defined in some other plugin, see below.</li>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]315</ul>
316</blockquote>
317</li>
318</ul>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]319<div class="section" id="external-options">
320<h2><a class="toc-backref" href="#id10">External options</a></h2>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]321<p>Sometimes, when linking several plugins together, one plugin needs to
322access options defined in some other plugin. Because of the way
Mikhail Glushenkovf9b1d792009-01-15 02:42:40 +0000[diff] [blame]323options are implemented, such options must be marked as
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]324<tt class="docutils literal"><span class="pre">extern</span></tt>. This is what the <tt class="docutils literal"><span class="pre">extern</span></tt> option property is
325for. Example:</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]326<pre class="literal-block">
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]327...
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]328(switch_option &quot;E&quot;, (extern))
329...
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]330</pre>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]331<p>See also the section on plugin <a class="reference internal" href="#priorities">priorities</a>.</p>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]332</div>
Reid Spencerb1254a12004-08-09 03:08:29 +0000[diff] [blame]333</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]334<div class="section" id="conditional-evaluation">
335<span id="case"></span><h1><a class="toc-backref" href="#id11">Conditional evaluation</a></h1>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]336<p>The 'case' construct is the main means by which programmability is
337achieved in LLVMC. It can be used to calculate edge weights, program
338actions and modify the shell commands to be executed. The 'case'
339expression is designed after the similarly-named construct in
340functional languages and takes the form <tt class="docutils literal"><span class="pre">(case</span> <span class="pre">(test_1),</span> <span class="pre">statement_1,</span>
341<span class="pre">(test_2),</span> <span class="pre">statement_2,</span> <span class="pre">...</span> <span class="pre">(test_N),</span> <span class="pre">statement_N)</span></tt>. The statements
342are evaluated only if the corresponding tests evaluate to true.</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]343<p>Examples:</p>
344<pre class="literal-block">
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]345// Edge weight calculation
346
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]347// Increases edge weight by 5 if &quot;-A&quot; is provided on the
348// command-line, and by 5 more if &quot;-B&quot; is also provided.
349(case
350 (switch_on &quot;A&quot;), (inc_weight 5),
351 (switch_on &quot;B&quot;), (inc_weight 5))
352
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]353
354// Tool command line specification
355
356// Evaluates to &quot;cmdline1&quot; if the option &quot;-A&quot; is provided on the
357// command line; to &quot;cmdline2&quot; if &quot;-B&quot; is provided;
358// otherwise to &quot;cmdline3&quot;.
359
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]360(case
361 (switch_on &quot;A&quot;), &quot;cmdline1&quot;,
362 (switch_on &quot;B&quot;), &quot;cmdline2&quot;,
363 (default), &quot;cmdline3&quot;)
364</pre>
365<p>Note the slight difference in 'case' expression handling in contexts
366of edge weights and command line specification - in the second example
367the value of the <tt class="docutils literal"><span class="pre">&quot;B&quot;</span></tt> switch is never checked when switch <tt class="docutils literal"><span class="pre">&quot;A&quot;</span></tt> is
368enabled, and the whole expression always evaluates to <tt class="docutils literal"><span class="pre">&quot;cmdline1&quot;</span></tt> in
369that case.</p>
370<p>Case expressions can also be nested, i.e. the following is legal:</p>
371<pre class="literal-block">
372(case (switch_on &quot;E&quot;), (case (switch_on &quot;o&quot;), ..., (default), ...)
373 (default), ...)
374</pre>
375<p>You should, however, try to avoid doing that because it hurts
376readability. It is usually better to split tool descriptions and/or
377use TableGen inheritance instead.</p>
378<ul class="simple">
379<li>Possible tests are:<ul>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]380<li><tt class="docutils literal"><span class="pre">switch_on</span></tt> - Returns true if a given command-line switch is
381provided by the user. Example: <tt class="docutils literal"><span class="pre">(switch_on</span> <span class="pre">&quot;opt&quot;)</span></tt>.</li>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]382<li><tt class="docutils literal"><span class="pre">parameter_equals</span></tt> - Returns true if a command-line parameter equals
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]383a given value.
384Example: <tt class="docutils literal"><span class="pre">(parameter_equals</span> <span class="pre">&quot;W&quot;,</span> <span class="pre">&quot;all&quot;)</span></tt>.</li>
385<li><tt class="docutils literal"><span class="pre">element_in_list</span></tt> - Returns true if a command-line parameter
386list contains a given value.
387Example: <tt class="docutils literal"><span class="pre">(parameter_in_list</span> <span class="pre">&quot;l&quot;,</span> <span class="pre">&quot;pthread&quot;)</span></tt>.</li>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]388<li><tt class="docutils literal"><span class="pre">input_languages_contain</span></tt> - Returns true if a given language
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]389belongs to the current input language set.
390Example: <tt class="docutils literal"><span class="pre">(input_languages_contain</span> <span class="pre">&quot;c++&quot;)</span></tt>.</li>
391<li><tt class="docutils literal"><span class="pre">in_language</span></tt> - Evaluates to true if the input file language
392equals to the argument. At the moment works only with <tt class="docutils literal"><span class="pre">cmd_line</span></tt>
393and <tt class="docutils literal"><span class="pre">actions</span></tt> (on non-join nodes).
394Example: <tt class="docutils literal"><span class="pre">(in_language</span> <span class="pre">&quot;c++&quot;)</span></tt>.</li>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]395<li><tt class="docutils literal"><span class="pre">not_empty</span></tt> - Returns true if a given option (which should be
396either a parameter or a parameter list) is set by the
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]397user.
398Example: <tt class="docutils literal"><span class="pre">(not_empty</span> <span class="pre">&quot;o&quot;)</span></tt>.</li>
Mikhail Glushenkov2d0484c2008-12-17 02:47:30 +0000[diff] [blame]399<li><tt class="docutils literal"><span class="pre">empty</span></tt> - The opposite of <tt class="docutils literal"><span class="pre">not_empty</span></tt>. Equivalent to <tt class="docutils literal"><span class="pre">(not</span> <span class="pre">(not_empty</span>
400<span class="pre">X))</span></tt>. Provided for convenience.</li>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]401<li><tt class="docutils literal"><span class="pre">default</span></tt> - Always evaluates to true. Should always be the last
402test in the <tt class="docutils literal"><span class="pre">case</span></tt> expression.</li>
403<li><tt class="docutils literal"><span class="pre">and</span></tt> - A standard logical combinator that returns true iff all
404of its arguments return true. Used like this: <tt class="docutils literal"><span class="pre">(and</span> <span class="pre">(test1),</span>
405<span class="pre">(test2),</span> <span class="pre">...</span> <span class="pre">(testN))</span></tt>. Nesting of <tt class="docutils literal"><span class="pre">and</span></tt> and <tt class="docutils literal"><span class="pre">or</span></tt> is allowed,
406but not encouraged.</li>
407<li><tt class="docutils literal"><span class="pre">or</span></tt> - Another logical combinator that returns true only if any
408one of its arguments returns true. Example: <tt class="docutils literal"><span class="pre">(or</span> <span class="pre">(test1),</span>
409<span class="pre">(test2),</span> <span class="pre">...</span> <span class="pre">(testN))</span></tt>.</li>
410</ul>
411</li>
412</ul>
Reid Spencer46d21922004-08-22 18:06:59 +0000[diff] [blame]413</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]414<div class="section" id="writing-a-tool-description">
415<h1><a class="toc-backref" href="#id12">Writing a tool description</a></h1>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]416<p>As was said earlier, nodes in the compilation graph represent tools,
417which are described separately. A tool definition looks like this
418(taken from the <tt class="docutils literal"><span class="pre">include/llvm/CompilerDriver/Tools.td</span></tt> file):</p>
419<pre class="literal-block">
420def llvm_gcc_cpp : Tool&lt;[
421 (in_language &quot;c++&quot;),
422 (out_language &quot;llvm-assembler&quot;),
423 (output_suffix &quot;bc&quot;),
424 (cmd_line &quot;llvm-g++ -c $INFILE -o $OUTFILE -emit-llvm&quot;),
425 (sink)
426 ]&gt;;
427</pre>
428<p>This defines a new tool called <tt class="docutils literal"><span class="pre">llvm_gcc_cpp</span></tt>, which is an alias for
429<tt class="docutils literal"><span class="pre">llvm-g++</span></tt>. As you can see, a tool definition is just a list of
430properties; most of them should be self-explanatory. The <tt class="docutils literal"><span class="pre">sink</span></tt>
431property means that this tool should be passed all command-line
432options that aren't mentioned in the option list.</p>
433<p>The complete list of all currently implemented tool properties follows.</p>
434<ul class="simple">
435<li>Possible tool properties:<ul>
436<li><tt class="docutils literal"><span class="pre">in_language</span></tt> - input language name. Can be either a string or a
437list, in case the tool supports multiple input languages.</li>
438<li><tt class="docutils literal"><span class="pre">out_language</span></tt> - output language name. Tools are not allowed to
439have multiple output languages.</li>
440<li><tt class="docutils literal"><span class="pre">output_suffix</span></tt> - output file suffix. Can also be changed
441dynamically, see documentation on actions.</li>
442<li><tt class="docutils literal"><span class="pre">cmd_line</span></tt> - the actual command used to run the tool. You can
443use <tt class="docutils literal"><span class="pre">$INFILE</span></tt> and <tt class="docutils literal"><span class="pre">$OUTFILE</span></tt> variables, output redirection
444with <tt class="docutils literal"><span class="pre">&gt;</span></tt>, hook invocations (<tt class="docutils literal"><span class="pre">$CALL</span></tt>), environment variables
445(via <tt class="docutils literal"><span class="pre">$ENV</span></tt>) and the <tt class="docutils literal"><span class="pre">case</span></tt> construct.</li>
446<li><tt class="docutils literal"><span class="pre">join</span></tt> - this tool is a &quot;join node&quot; in the graph, i.e. it gets a
447list of input files and joins them together. Used for linkers.</li>
448<li><tt class="docutils literal"><span class="pre">sink</span></tt> - all command-line options that are not handled by other
449tools are passed to this tool.</li>
450<li><tt class="docutils literal"><span class="pre">actions</span></tt> - A single big <tt class="docutils literal"><span class="pre">case</span></tt> expression that specifies how
451this tool reacts on command-line options (described in more detail
452below).</li>
453</ul>
454</li>
455</ul>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]456<div class="section" id="actions">
457<h2><a class="toc-backref" href="#id13">Actions</a></h2>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]458<p>A tool often needs to react to command-line options, and this is
459precisely what the <tt class="docutils literal"><span class="pre">actions</span></tt> property is for. The next example
460illustrates this feature:</p>
461<pre class="literal-block">
462def llvm_gcc_linker : Tool&lt;[
463 (in_language &quot;object-code&quot;),
464 (out_language &quot;executable&quot;),
465 (output_suffix &quot;out&quot;),
466 (cmd_line &quot;llvm-gcc $INFILE -o $OUTFILE&quot;),
467 (join),
468 (actions (case (not_empty &quot;L&quot;), (forward &quot;L&quot;),
469 (not_empty &quot;l&quot;), (forward &quot;l&quot;),
470 (not_empty &quot;dummy&quot;),
471 [(append_cmd &quot;-dummy1&quot;), (append_cmd &quot;-dummy2&quot;)])
472 ]&gt;;
473</pre>
474<p>The <tt class="docutils literal"><span class="pre">actions</span></tt> tool property is implemented on top of the omnipresent
475<tt class="docutils literal"><span class="pre">case</span></tt> expression. It associates one or more different <em>actions</em>
476with given conditions - in the example, the actions are <tt class="docutils literal"><span class="pre">forward</span></tt>,
477which forwards a given option unchanged, and <tt class="docutils literal"><span class="pre">append_cmd</span></tt>, which
478appends a given string to the tool execution command. Multiple actions
479can be associated with a single condition by using a list of actions
480(used in the example to append some dummy options). The same <tt class="docutils literal"><span class="pre">case</span></tt>
481construct can also be used in the <tt class="docutils literal"><span class="pre">cmd_line</span></tt> property to modify the
482tool command line.</p>
483<p>The &quot;join&quot; property used in the example means that this tool behaves
484like a linker.</p>
485<p>The list of all possible actions follows.</p>
486<ul>
487<li><p class="first">Possible actions:</p>
488<blockquote>
489<ul class="simple">
490<li><tt class="docutils literal"><span class="pre">append_cmd</span></tt> - append a string to the tool invocation
491command.
Mikhail Glushenkov2d0484c2008-12-17 02:47:30 +0000[diff] [blame]492Example: <tt class="docutils literal"><span class="pre">(case</span> <span class="pre">(switch_on</span> <span class="pre">&quot;pthread&quot;),</span> <span class="pre">(append_cmd</span>
493<span class="pre">&quot;-lpthread&quot;))</span></tt></li>
494<li><tt class="docutils literal"><span class="pre">error`</span> <span class="pre">-</span> <span class="pre">exit</span> <span class="pre">with</span> <span class="pre">error.</span>
495<span class="pre">Example:</span> <span class="pre">``(error</span> <span class="pre">&quot;Mixing</span> <span class="pre">-c</span> <span class="pre">and</span> <span class="pre">-S</span> <span class="pre">is</span> <span class="pre">not</span> <span class="pre">allowed!&quot;)</span></tt>.</li>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]496<li><tt class="docutils literal"><span class="pre">forward</span></tt> - forward an option unchanged.
497Example: <tt class="docutils literal"><span class="pre">(forward</span> <span class="pre">&quot;Wall&quot;)</span></tt>.</li>
498<li><tt class="docutils literal"><span class="pre">forward_as</span></tt> - Change the name of an option, but forward the
499argument unchanged.
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]500Example: <tt class="docutils literal"><span class="pre">(forward_as</span> <span class="pre">&quot;O0&quot;,</span> <span class="pre">&quot;--disable-optimization&quot;)</span></tt>.</li>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]501<li><tt class="docutils literal"><span class="pre">output_suffix</span></tt> - modify the output suffix of this
502tool.
503Example: <tt class="docutils literal"><span class="pre">(output_suffix</span> <span class="pre">&quot;i&quot;)</span></tt>.</li>
504<li><tt class="docutils literal"><span class="pre">stop_compilation</span></tt> - stop compilation after this tool processes
505its input. Used without arguments.</li>
506<li><tt class="docutils literal"><span class="pre">unpack_values</span></tt> - used for for splitting and forwarding
507comma-separated lists of options, e.g. <tt class="docutils literal"><span class="pre">-Wa,-foo=bar,-baz</span></tt> is
508converted to <tt class="docutils literal"><span class="pre">-foo=bar</span> <span class="pre">-baz</span></tt> and appended to the tool invocation
509command.
510Example: <tt class="docutils literal"><span class="pre">(unpack_values</span> <span class="pre">&quot;Wa,&quot;)</span></tt>.</li>
511</ul>
512</blockquote>
513</li>
514</ul>
515</div>
516</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]517<div class="section" id="language-map">
518<h1><a class="toc-backref" href="#id14">Language map</a></h1>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]519<p>If you are adding support for a new language to LLVMC, you'll need to
520modify the language map, which defines mappings from file extensions
521to language names. It is used to choose the proper toolchain(s) for a
522given input file set. Language map definition looks like this:</p>
Anton Korobeynikov74120312008-06-09 04:15:49 +0000[diff] [blame]523<pre class="literal-block">
524def LanguageMap : LanguageMap&lt;
525 [LangToSuffixes&lt;&quot;c++&quot;, [&quot;cc&quot;, &quot;cp&quot;, &quot;cxx&quot;, &quot;cpp&quot;, &quot;CPP&quot;, &quot;c++&quot;, &quot;C&quot;]&gt;,
526 LangToSuffixes&lt;&quot;c&quot;, [&quot;c&quot;]&gt;,
527 ...
528 ]&gt;;
529</pre>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]530<p>For example, without those definitions the following command wouldn't work:</p>
531<pre class="literal-block">
532$ llvmc hello.cpp
533llvmc: Unknown suffix: cpp
534</pre>
535<p>The language map entries should be added only for tools that are
536linked with the root node. Since tools are not allowed to have
537multiple output languages, for nodes &quot;inside&quot; the graph the input and
538output languages should match. This is enforced at compile-time.</p>
Reid Spencer46d21922004-08-22 18:06:59 +0000[diff] [blame]539</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]540<div class="section" id="more-advanced-topics">
541<h1><a class="toc-backref" href="#id15">More advanced topics</a></h1>
542<div class="section" id="hooks-and-environment-variables">
543<span id="hooks"></span><h2><a class="toc-backref" href="#id16">Hooks and environment variables</a></h2>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]544<p>Normally, LLVMC executes programs from the system <tt class="docutils literal"><span class="pre">PATH</span></tt>. Sometimes,
Mikhail Glushenkov5303c752009-01-28 03:47:38 +0000[diff] [blame]545this is not sufficient: for example, we may want to specify tool paths
546or names in the configuration file. This can be easily achieved via
547the hooks mechanism. To write your own hooks, just add their
548definitions to the <tt class="docutils literal"><span class="pre">PluginMain.cpp</span></tt> or drop a <tt class="docutils literal"><span class="pre">.cpp</span></tt> file into the
549your plugin directory. Hooks should live in the <tt class="docutils literal"><span class="pre">hooks</span></tt> namespace
550and have the signature <tt class="docutils literal"><span class="pre">std::string</span> <span class="pre">hooks::MyHookName</span> <span class="pre">([const</span> <span class="pre">char*</span>
551<span class="pre">Arg0</span> <span class="pre">[</span> <span class="pre">const</span> <span class="pre">char*</span> <span class="pre">Arg2</span> <span class="pre">[,</span> <span class="pre">...]]])</span></tt>. They can be used from the
552<tt class="docutils literal"><span class="pre">cmd_line</span></tt> tool property:</p>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]553<pre class="literal-block">
554(cmd_line &quot;$CALL(MyHook)/path/to/file -o $CALL(AnotherHook)&quot;)
555</pre>
Mikhail Glushenkov5303c752009-01-28 03:47:38 +0000[diff] [blame]556<p>To pass arguments to hooks, use the following syntax:</p>
557<pre class="literal-block">
558(cmd_line &quot;$CALL(MyHook, 'Arg1', 'Arg2', 'Arg # 3')/path/to/file -o1 -o2&quot;)
559</pre>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]560<p>It is also possible to use environment variables in the same manner:</p>
561<pre class="literal-block">
562(cmd_line &quot;$ENV(VAR1)/path/to/file -o $ENV(VAR2)&quot;)
563</pre>
564<p>To change the command line string based on user-provided options use
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]565the <tt class="docutils literal"><span class="pre">case</span></tt> expression (documented <a class="reference internal" href="#case">above</a>):</p>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]566<pre class="literal-block">
567(cmd_line
568 (case
569 (switch_on &quot;E&quot;),
570 &quot;llvm-g++ -E -x c $INFILE -o $OUTFILE&quot;,
571 (default),
572 &quot;llvm-g++ -c -x c $INFILE -o $OUTFILE -emit-llvm&quot;))
573</pre>
574</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]575<div class="section" id="how-plugins-are-loaded">
576<span id="priorities"></span><h2><a class="toc-backref" href="#id17">How plugins are loaded</a></h2>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]577<p>It is possible for LLVMC plugins to depend on each other. For example,
578one can create edges between nodes defined in some other plugin. To
579make this work, however, that plugin should be loaded first. To
580achieve this, the concept of plugin priority was introduced. By
581default, every plugin has priority zero; to specify the priority
582explicitly, put the following line in your plugin's TableGen file:</p>
583<pre class="literal-block">
584def Priority : PluginPriority&lt;$PRIORITY_VALUE&gt;;
585# Where PRIORITY_VALUE is some integer &gt; 0
586</pre>
587<p>Plugins are loaded in order of their (increasing) priority, starting
588with 0. Therefore, the plugin with the highest priority value will be
589loaded last.</p>
590</div>
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]591<div class="section" id="debugging">
592<h2><a class="toc-backref" href="#id18">Debugging</a></h2>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]593<p>When writing LLVMC plugins, it can be useful to get a visual view of
594the resulting compilation graph. This can be achieved via the command
Mikhail Glushenkovd6d2efc2009-05-06 01:41:47 +0000[diff] [blame^]595line option <tt class="docutils literal"><span class="pre">--view-graph</span></tt>. This command assumes that <a class="reference external" href="http://www.graphviz.org/">Graphviz</a> and
596<a class="reference external" href="http://pages.cs.wisc.edu/~ghost/">Ghostview</a> are installed. There is also a <tt class="docutils literal"><span class="pre">--write-graph</span></tt> option that
Mikhail Glushenkovd5652032008-12-13 02:28:58 +0000[diff] [blame]597creates a Graphviz source file (<tt class="docutils literal"><span class="pre">compilation-graph.dot</span></tt>) in the
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]598current directory.</p>
Mikhail Glushenkovf9b1d792009-01-15 02:42:40 +0000[diff] [blame]599<p>Another useful <tt class="docutils literal"><span class="pre">llvmc</span></tt> option is <tt class="docutils literal"><span class="pre">--check-graph</span></tt>. It checks the
600compilation graph for common errors like mismatched output/input
601language names, multiple default edges and cycles. These checks can't
602be performed at compile-time because the plugins can load code
603dynamically. When invoked with <tt class="docutils literal"><span class="pre">--check-graph</span></tt>, <tt class="docutils literal"><span class="pre">llvmc</span></tt> doesn't
604perform any compilation tasks and returns the number of encountered
605errors as its status code.</p>
Mikhail Glushenkov90531542008-12-11 23:43:14 +0000[diff] [blame]606<hr />
Anton Korobeynikov28b66702008-06-09 04:17:51 +0000[diff] [blame]607<address>
Mikhail Glushenkovd5652032008-12-13 02:28:58 +0000[diff] [blame]608<a href="http://jigsaw.w3.org/css-validator/check/referer">
609<img src="http://jigsaw.w3.org/css-validator/images/vcss-blue"
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613 alt="Valid XHTML 1.0 Transitional"/></a>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]614
Mikhail Glushenkovd5652032008-12-13 02:28:58 +0000[diff] [blame]615<a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a><br />
616<a href="http://llvm.org">LLVM Compiler Infrastructure</a><br />
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]617
Mikhail Glushenkov4ad0d572009-03-27 12:58:29 +0000[diff] [blame]618Last modified: $Date: 2008-12-11 11:34:48 -0600 (Thu, 11 Dec 2008) $
Mikhail Glushenkovd5652032008-12-13 02:28:58 +0000[diff] [blame]619</address></div>
Mikhail Glushenkov68319f82008-12-11 23:24:40 +0000[diff] [blame]620</div>
621</div>
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