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