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- <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
- <title>The LLVM Compiler Driver (llvmc)</title>
- <link rel="stylesheet" href="llvm.css" type="text/css">
- <meta name="author" content="Reid Spencer">
- <meta name="description"
- content="A description of the use and design of the LLVM Compiler Driver.">
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+<meta name="generator" content="Docutils 0.5: http://docutils.sourceforge.net/" />
+<title>Customizing LLVMC: Reference Manual</title>
+<link rel="stylesheet" href="llvm.css" type="text/css" />
</head>
<body>
-<div class="doc_title">The LLVM Compiler Driver (llvmc)</div>
-<p class="doc_warning">NOTE: This document is a work in progress!</p>
-<ol>
- <li><a href="#abstract">Abstract</a></li>
- <li><a href="#introduction">Introduction</a>
- <ol>
- <li><a href="#purpose">Purpose</a></li>
- <li><a href="#operation">Operation</a></li>
- <li><a href="#phases">Phases</a></li>
- <li><a href="#actions">Actions</a></li>
- </ol>
- </li>
- <li><a href="#configuration">Configuration</a>
- <ol>
- <li><a href="#overview">Overview</a></li>
- <li><a href="#filetypes">Configuration Files</a></li>
- <li><a href="#syntax">Syntax</a></li>
- <li><a href="#substitutions">Substitutions</a></li>
- <li><a href="#sample">Sample Config File</a></li>
- </ol>
- <li><a href="#glossary">Glossary</a>
-</ol>
+<div class="document" id="customizing-llvmc-reference-manual">
+<h1 class="title">Customizing LLVMC: Reference Manual</h1>
+
+<!-- This file was automatically generated by rst2html.
+Please do not edit directly!
+The ReST source lives in the directory 'tools/llvmc/doc'. -->
+<div class="contents topic" id="contents">
+<p class="topic-title first">Contents</p>
+<ul class="simple">
+<li><a class="reference internal" href="#introduction" id="id4">Introduction</a></li>
+<li><a class="reference internal" href="#compiling-with-llvmc" id="id5">Compiling with LLVMC</a></li>
+<li><a class="reference internal" href="#predefined-options" id="id6">Predefined options</a></li>
+<li><a class="reference internal" href="#compiling-llvmc-plugins" id="id7">Compiling LLVMC plugins</a></li>
+<li><a class="reference internal" href="#compiling-standalone-llvmc-based-drivers" id="id8">Compiling standalone LLVMC-based drivers</a></li>
+<li><a class="reference internal" href="#customizing-llvmc-the-compilation-graph" id="id9">Customizing LLVMC: the compilation graph</a></li>
+<li><a class="reference internal" href="#describing-options" id="id10">Describing options</a><ul>
+<li><a class="reference internal" href="#external-options" id="id11">External options</a></li>
+</ul>
+</li>
+<li><a class="reference internal" href="#conditional-evaluation" id="id12">Conditional evaluation</a></li>
+<li><a class="reference internal" href="#writing-a-tool-description" id="id13">Writing a tool description</a><ul>
+<li><a class="reference internal" href="#actions" id="id14">Actions</a></li>
+</ul>
+</li>
+<li><a class="reference internal" href="#language-map" id="id15">Language map</a></li>
+<li><a class="reference internal" href="#more-advanced-topics" id="id16">More advanced topics</a><ul>
+<li><a class="reference internal" href="#hooks-and-environment-variables" id="id17">Hooks and environment variables</a></li>
+<li><a class="reference internal" href="#how-plugins-are-loaded" id="id18">How plugins are loaded</a></li>
+<li><a class="reference internal" href="#debugging" id="id19">Debugging</a></li>
+</ul>
+</li>
+</ul>
+</div>
<div class="doc_author">
-<p>Written by <a href="mailto:rspencer@x10sys.com">Reid Spencer</a>
-</p>
+<p>Written by <a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a></p>
+</div><div class="section" id="introduction">
+<h1><a class="toc-backref" href="#id4">Introduction</a></h1>
+<p>LLVMC is a generic compiler driver, designed to be customizable and
+extensible. It plays the same role for LLVM as the <tt class="docutils literal"><span class="pre">gcc</span></tt> program
+does for GCC - LLVMC's job is essentially to transform a set of input
+files into a set of targets depending on configuration rules and user
+options. What makes LLVMC different is that these transformation rules
+are completely customizable - in fact, LLVMC knows nothing about the
+specifics of transformation (even the command-line options are mostly
+not hard-coded) and regards the transformation structure as an
+abstract graph. The structure of this graph is completely determined
+by plugins, which can be either statically or dynamically linked. This
+makes it possible to easily adapt LLVMC for other purposes - for
+example, as a build tool for game resources.</p>
+<p>Because LLVMC employs <a class="reference external" href="http://llvm.org/docs/TableGenFundamentals.html">TableGen</a> as its configuration language, you
+need to be familiar with it to customize LLVMC.</p>
</div>
-
-<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="abstract">Abstract</a></div>
-<!-- *********************************************************************** -->
-<div class="doc_text">
- <p>This document describes the requirements, design, and configuration of the
- LLVM compiler driver, <tt>llvmc</tt>. The compiler driver knows about LLVM's
- tool set and can be configured to know about a variety of compilers for
- source languages. It uses this knowledge to execute the tools necessary
- to accomplish general compilation, optimization, and linking tasks. The main
- purpose of <tt>llvmc</tt> is to provide a simple and consistent interface to
- all compilation tasks. This reduces the burden on the end user who can just
- learn to use <tt>llvmc</tt> instead of the entire LLVM tool set and all the
- source language compilers compatible with LLVM.</p>
+<div class="section" id="compiling-with-llvmc">
+<h1><a class="toc-backref" href="#id5">Compiling with LLVMC</a></h1>
+<p>LLVMC tries hard to be as compatible with <tt class="docutils literal"><span class="pre">gcc</span></tt> as possible,
+although there are some small differences. Most of the time, however,
+you shouldn't be able to notice them:</p>
+<pre class="literal-block">
+$ # This works as expected:
+$ llvmc -O3 -Wall hello.cpp
+$ ./a.out
+hello
+</pre>
+<p>One nice feature of LLVMC is that one doesn't have to distinguish between
+different compilers for different languages (think <tt class="docutils literal"><span class="pre">g++</span></tt> vs. <tt class="docutils literal"><span class="pre">gcc</span></tt>) - the
+right toolchain is chosen automatically based on input language names (which
+are, in turn, determined from file extensions). If you want to force files
+ending with ".c" to compile as C++, 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>
+<pre class="literal-block">
+$ # hello.c is really a C++ file
+$ llvmc -x c++ hello.c
+$ ./a.out
+hello
+</pre>
+<p>On the other hand, when using LLVMC as a linker to combine several C++
+object files you should provide the <tt class="docutils literal"><span class="pre">--linker</span></tt> option since it's
+impossible for LLVMC to choose the right linker in that case:</p>
+<pre class="literal-block">
+$ llvmc -c hello.cpp
+$ llvmc hello.o
+[A lot of link-time errors skipped]
+$ llvmc --linker=c++ hello.o
+$ ./a.out
+hello
+</pre>
+<p>By default, LLVMC uses <tt class="docutils literal"><span class="pre">llvm-gcc</span></tt> to compile the source code. It is
+also possible to choose the work-in-progress <tt class="docutils literal"><span class="pre">clang</span></tt> compiler with
+the <tt class="docutils literal"><span class="pre">-clang</span></tt> option.</p>
</div>
-<!-- *********************************************************************** -->
-<div class="doc_section"> <a name="introduction">Introduction</a></div>
-<!-- *********************************************************************** -->
-<div class="doc_text">
- <p>The <tt>llvmc</tt> <a href="#def_tool">tool</a> is a configurable compiler
- <a href="#def_driver">driver</a>. As such, it isn't a compiler, optimizer,
- or a linker itself but it drives (invokes) other software that perform those
- tasks. If you are familiar with the GNU Compiler Collection's <tt>gcc</tt>
- tool, <tt>llvmc</tt> is very similar.</p>
- <p>The following introductory sections will help you understand why this tool
- is necessary and what it does.</p>
+<div class="section" id="predefined-options">
+<h1><a class="toc-backref" href="#id6">Predefined options</a></h1>
+<p>LLVMC has some built-in options that can't be overridden in the
+configuration libraries:</p>
+<ul class="simple">
+<li><tt class="docutils literal"><span class="pre">-o</span> <span class="pre">FILE</span></tt> - Output file name.</li>
+<li><tt class="docutils literal"><span class="pre">-x</span> <span class="pre">LANGUAGE</span></tt> - Specify the language of the following input files
+until the next -x option.</li>
+<li><tt class="docutils literal"><span class="pre">-load</span> <span class="pre">PLUGIN_NAME</span></tt> - Load the specified plugin DLL. Example:
+<tt class="docutils literal"><span class="pre">-load</span> <span class="pre">$LLVM_DIR/Release/lib/LLVMCSimple.so</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">-v</span></tt> - Enable verbose mode, i.e. print out all executed commands.</li>
+<li><tt class="docutils literal"><span class="pre">--check-graph</span></tt> - Check the compilation for common errors like mismatched
+output/input language names, multiple default edges and cycles. Because of
+plugins, these checks can't be performed at compile-time. Exit with code zero
+if no errors were found, and return the number of found errors
+otherwise. Hidden option, useful for debugging LLVMC plugins.</li>
+<li><tt class="docutils literal"><span class="pre">--view-graph</span></tt> - Show a graphical representation of the compilation graph
+and 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
+option, useful for debugging LLVMC plugins.</li>
+<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
+directory with the compilation graph description in Graphviz format (identical
+to 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 to set the output file name. Hidden option, useful for debugging LLVMC
+plugins.</li>
+<li><tt class="docutils literal"><span class="pre">--save-temps</span></tt> - Write temporary files to the current directory
+and do not delete them on exit. Hidden option, useful for debugging.</li>
+<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
+their standard meaning.</li>
+</ul>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="purpose">Purpose</a></div>
-<div class="doc_text">
- <p><tt>llvmc</tt> was invented to make compilation of user programs with
- LLVM-based tools easier. To accomplish this, <tt>llvmc</tt> strives to:</p>
- <ul>
- <li>Be the single point of access to most of the LLVM tool set.</li>
- <li>Hide the complexities of the LLVM tools through a single interface.</li>
- <li>Provide a consistent interface for compiling all languages.</li>
- </ul>
- <p>Additionally, <tt>llvmc</tt> makes it easier to write a compiler for use
- with LLVM, because it:</p>
- <ul>
- <li>Makes integration of existing non-LLVM tools simple.</li>
- <li>Extends the capabilities of minimal compiler tools by optimizing their
- output.</li>
- <li>Reduces the number of interfaces a compiler writer must know about
- before a working compiler can be completed (essentially only the VMCore
- interfaces need to be understood).</li>
- <li>Supports source language translator invocation via both dynamically
- loadable shared objects and invocation of an executable.</li>
- </ul>
+<div class="section" id="compiling-llvmc-plugins">
+<h1><a class="toc-backref" href="#id7">Compiling LLVMC plugins</a></h1>
+<p>It's easiest to start working on your own LLVMC plugin by copying the
+skeleton project which lives under <tt class="docutils literal"><span class="pre">$LLVMC_DIR/plugins/Simple</span></tt>:</p>
+<pre class="literal-block">
+$ cd $LLVMC_DIR/plugins
+$ cp -r Simple MyPlugin
+$ cd MyPlugin
+$ ls
+Makefile PluginMain.cpp Simple.td
+</pre>
+<p>As you can see, our basic plugin consists of only two files (not
+counting the build script). <tt class="docutils literal"><span class="pre">Simple.td</span></tt> contains TableGen
+description of the compilation graph; its format is documented in the
+following sections. <tt class="docutils literal"><span class="pre">PluginMain.cpp</span></tt> is just a helper file used to
+compile the auto-generated C++ code produced from TableGen source. It
+can also contain hook definitions (see <a class="reference internal" href="#hooks">below</a>).</p>
+<p>The first thing that you should do is to change the <tt class="docutils literal"><span class="pre">LLVMC_PLUGIN</span></tt>
+variable in the <tt class="docutils literal"><span class="pre">Makefile</span></tt> to avoid conflicts (since this variable
+is used to name the resulting library):</p>
+<pre class="literal-block">
+LLVMC_PLUGIN=MyPlugin
+</pre>
+<p>It is also a good idea to rename <tt class="docutils literal"><span class="pre">Simple.td</span></tt> to something less
+generic:</p>
+<pre class="literal-block">
+$ mv Simple.td MyPlugin.td
+</pre>
+<p>To build your plugin as a dynamic library, just <tt class="docutils literal"><span class="pre">cd</span></tt> to its source
+directory and run <tt class="docutils literal"><span class="pre">make</span></tt>. The resulting file will be called
+<tt class="docutils literal"><span class="pre">plugin_llvmc_$(LLVMC_PLUGIN).$(DLL_EXTENSION)</span></tt> (in our case,
+<tt class="docutils literal"><span class="pre">plugin_llvmc_MyPlugin.so</span></tt>). This library can be then loaded in with the
+<tt class="docutils literal"><span class="pre">-load</span></tt> option. Example:</p>
+<pre class="literal-block">
+$ cd $LLVMC_DIR/plugins/Simple
+$ make
+$ llvmc -load $LLVM_DIR/Release/lib/plugin_llvmc_Simple.so
+</pre>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="operation">Operation</a></div>
-<div class="doc_text">
- <p>At a high level, <tt>llvmc</tt> operation is very simple. The basic action
- taken by <tt>llvmc</tt> is to simply invoke some tool or set of tools to fill
- the user's request for compilation. Every execution of <tt>llvmc</tt>takes the
- following sequence of steps:</p>
- <dl>
- <dt><b>Collect Command Line Options</b></dt>
- <dd>The command line options provide the marching orders to <tt>llvmc</tt>
- on what actions it should perform. This is the request the user is making
- of <tt>llvmc</tt> and it is interpreted first. See the <tt>llvmc</tt>
- <a href="CommandGuide/html/llvmc.html">manual page</a> for details on the
- options.</dd>
- <dt><b>Read Configuration Files</b></dt>
- <dd>Based on the options and the suffixes of the filenames presented, a set
- of configuration files are read to configure the actions <tt>llvmc</tt> will
- take. Configuration files are provided by either LLVM or the
- compiler tools that <tt>llvmc</tt> invokes. These files determine what
- actions <tt>llvmc</tt> will take in response to the user's request. See
- the section on <a href="#configuration">configuration</a> for more details.
- </dd>
- <dt><b>Determine Phases To Execute</b></dt>
- <dd>Based on the command line options and configuration files,
- <tt>llvmc</tt> determines the compilation <a href="#phases">phases</a> that
- must be executed by the user's request. This is the primary work of
- <tt>llvmc</tt>.</dd>
- <dt><b>Determine Actions To Execute</b></dt>
- <dd>Each <a href="#phases">phase</a> to be executed can result in the
- invocation of one or more <a href="#actions">actions</a>. An action is
- either a whole program or a function in a dynamically linked shared library.
- In this step, <tt>llvmc</tt> determines the sequence of actions that must be
- executed. Actions will always be executed in a deterministic order.</dd>
- <dt><b>Execute Actions</b></dt>
- <dd>The <a href="#actions">actions</a> necessary to support the user's
- original request are executed sequentially and deterministically. All
- actions result in either the invocation of a whole program to perform the
- action or the loading of a dynamically linkable shared library and invocation
- of a standard interface function within that library.</dd>
- <dt><b>Termination</b></dt>
- <dd>If any action fails (returns a non-zero result code), <tt>llvmc</tt>
- also fails and returns the result code from the failing action. If
- everything succeeds, <tt>llvmc</tt> will return a zero result code.</dd>
- </dl>
- <p><tt>llvmc</tt>'s operation must be simple, regular and predictable.
- Developers need to be able to rely on it to take a consistent approach to
- compilation. For example, the invocation:</p>
- <code>
- llvmc -O2 x.c y.c z.c -o xyz</code>
- <p>must produce <i>exactly</i> the same results as:</p>
- <pre><tt>
- llvmc -O2 x.c -o x.o
- llvmc -O2 y.c -o y.o
- llvmc -O2 z.c -o z.o
- llvmc -O2 x.o y.o z.o -o xyz</tt></pre>
- <p>To accomplish this, <tt>llvmc</tt> uses a very simple goal oriented
- procedure to do its work. The overall goal is to produce a functioning
- executable. To accomplish this, <tt>llvmc</tt> always attempts to execute a
- series of compilation <a href="#def_phase">phases</a> in the same sequence.
- However, the user's options to <tt>llvmc</tt> can cause the sequence of phases
- to start in the middle or finish early.</p>
+<div class="section" id="compiling-standalone-llvmc-based-drivers">
+<h1><a class="toc-backref" href="#id8">Compiling standalone LLVMC-based drivers</a></h1>
+<p>By default, the <tt class="docutils literal"><span class="pre">llvmc</span></tt> executable consists of a driver core plus several
+statically linked plugins (<tt class="docutils literal"><span class="pre">Base</span></tt> and <tt class="docutils literal"><span class="pre">Clang</span></tt> at the moment). You can
+produce a standalone LLVMC-based driver executable by linking the core with your
+own plugins. The recommended way to do this is by starting with the provided
+<tt class="docutils literal"><span class="pre">Skeleton</span></tt> example (<tt class="docutils literal"><span class="pre">$LLVMC_DIR/example/Skeleton</span></tt>):</p>
+<pre class="literal-block">
+$ cd $LLVMC_DIR/example/
+$ cp -r Skeleton mydriver
+$ cd mydriver
+$ vim Makefile
+[...]
+$ make
+</pre>
+<p>If you're compiling LLVM with different source and object directories, then you
+must perform the following additional steps before running <tt class="docutils literal"><span class="pre">make</span></tt>:</p>
+<pre class="literal-block">
+# LLVMC_SRC_DIR = $LLVM_SRC_DIR/tools/llvmc/
+# LLVMC_OBJ_DIR = $LLVM_OBJ_DIR/tools/llvmc/
+$ cp $LLVMC_SRC_DIR/example/mydriver/Makefile \
+ $LLVMC_OBJ_DIR/example/mydriver/
+$ cd $LLVMC_OBJ_DIR/example/mydriver
+$ make
+</pre>
+<p>Another way to do the same thing is by using the following command:</p>
+<pre class="literal-block">
+$ cd $LLVMC_DIR
+$ make LLVMC_BUILTIN_PLUGINS=MyPlugin LLVMC_BASED_DRIVER_NAME=mydriver
+</pre>
+<p>This works with both srcdir == objdir and srcdir != objdir, but assumes that the
+plugin source directory was placed under <tt class="docutils literal"><span class="pre">$LLVMC_DIR/plugins</span></tt>.</p>
+<p>Sometimes, you will want a 'bare-bones' version of LLVMC that has no
+built-in plugins. It can be compiled with the following command:</p>
+<pre class="literal-block">
+$ cd $LLVMC_DIR
+$ make LLVMC_BUILTIN_PLUGINS=""
+</pre>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="phases"></a>Phases </div>
-<div class="doc_text">
- <p><tt>llvmc</tt> breaks every compilation task into the following five
- distinct phases:</p>
- <dl><dt><b>Preprocessing</b></dt><dd>Not all languages support preprocessing;
- but for those that do, this phase can be invoked. This phase is for
- languages that provide combining, filtering, or otherwise altering with the
- source language input before the translator parses it. Although C and C++
- are the most common users of this phase, other languages may provide their
- own preprocessor (whether its the C pre-processor or not).</dd>
- </dl>
- <dl><dt><b>Translation</b></dt><dd>The translation phase converts the source
- language input into something that LLVM can interpret and use for
- downstream phases. The translation is essentially from "non-LLVM form" to
- "LLVM form".</dd>
- </dl>
- <dl><dt><b>Optimization</b></dt><dd>Once an LLVM Module has been obtained from
- the translation phase, the program enters the optimization phase. This phase
- attempts to optimize all of the input provided on the command line according
- to the options provided.</dd>
- </dl>
- <dl><dt><b>Linking</b></dt><dd>The inputs are combined to form a complete
- program.</dd>
- </dl>
- <p>The following table shows the inputs, outputs, and command line options
- applicable to each phase.</p>
- <table>
- <tr>
- <th style="width: 10%">Phase</th>
- <th style="width: 25%">Inputs</th>
- <th style="width: 25%">Outputs</th>
- <th style="width: 40%">Options</th>
- </tr>
- <tr><td><b>Preprocessing</b></td>
- <td class="td_left"><ul><li>Source Language File</li></ul></td>
- <td class="td_left"><ul><li>Source Language File</li></ul></td>
- <td class="td_left"><dl>
- <dt><tt>-E</tt></dt>
- <dd>Stops the compilation after preprocessing</dd>
- </dl></td>
- </tr>
- <tr>
- <td><b>Translation</b></td>
- <td class="td_left"><ul>
- <li>Source Language File</li>
- </ul></td>
- <td class="td_left"><ul>
- <li>LLVM Assembly</li>
- <li>LLVM Bitcode</li>
- <li>LLVM C++ IR</li>
- </ul></td>
- <td class="td_left"><dl>
- <dt><tt>-c</tt></dt>
- <dd>Stops the compilation after translation so that optimization and
- linking are not done.</dd>
- <dt><tt>-S</tt></dt>
- <dd>Stops the compilation before object code is written so that only
- assembly code remains.</dd>
- </dl></td>
- </tr>
- <tr>
- <td><b>Optimization</b></td>
- <td class="td_left"><ul>
- <li>LLVM Assembly</li>
- <li>LLVM Bitcode</li>
- </ul></td>
- <td class="td_left"><ul>
- <li>LLVM Bitcode</li>
- </ul></td>
- <td class="td_left"><dl>
- <dt><tt>-Ox</tt>
- <dd>This group of options controls the amount of optimization
- performed.</dd>
- </dl></td>
- </tr>
- <tr>
- <td><b>Linking</b></td>
- <td class="td_left"><ul>
- <li>LLVM Bitcode</li>
- <li>Native Object Code</li>
- <li>LLVM Library</li>
- <li>Native Library</li>
- </ul></td>
- <td class="td_left"><ul>
- <li>LLVM Bitcode Executable</li>
- <li>Native Executable</li>
- </ul></td>
- <td class="td_left"><dl>
- <dt><tt>-L</tt></dt><dd>Specifies a path for library search.</dd>
- <dt><tt>-l</tt></dt><dd>Specifies a library to link in.</dd>
- </dl></td>
- </tr>
- </table>
+<div class="section" id="customizing-llvmc-the-compilation-graph">
+<h1><a class="toc-backref" href="#id9">Customizing LLVMC: the compilation graph</a></h1>
+<p>Each TableGen configuration file should include the common
+definitions:</p>
+<pre class="literal-block">
+include "llvm/CompilerDriver/Common.td"
+</pre>
+<p>Internally, LLVMC stores information about possible source
+transformations in form of a graph. Nodes in this graph represent
+tools, and edges between two nodes represent a transformation path. A
+special "root" node is used to mark entry points for the
+transformations. LLVMC also assigns a weight to each edge (more on
+this later) to choose between several alternative edges.</p>
+<p>The definition of the compilation graph (see file
+<tt class="docutils literal"><span class="pre">plugins/Base/Base.td</span></tt> for an example) is just a list of edges:</p>
+<pre class="literal-block">
+def CompilationGraph : CompilationGraph<[
+ Edge<"root", "llvm_gcc_c">,
+ Edge<"root", "llvm_gcc_assembler">,
+ ...
+
+ Edge<"llvm_gcc_c", "llc">,
+ Edge<"llvm_gcc_cpp", "llc">,
+ ...
+
+ OptionalEdge<"llvm_gcc_c", "opt", (case (switch_on "opt"),
+ (inc_weight))>,
+ OptionalEdge<"llvm_gcc_cpp", "opt", (case (switch_on "opt"),
+ (inc_weight))>,
+ ...
+
+ OptionalEdge<"llvm_gcc_assembler", "llvm_gcc_cpp_linker",
+ (case (input_languages_contain "c++"), (inc_weight),
+ (or (parameter_equals "linker", "g++"),
+ (parameter_equals "linker", "c++")), (inc_weight))>,
+ ...
+
+ ]>;
+</pre>
+<p>As you can see, the edges can be either default or optional, where
+optional edges are differentiated by an additional <tt class="docutils literal"><span class="pre">case</span></tt> expression
+used to calculate the weight of this edge. Notice also that we refer
+to tools via their names (as strings). This makes it possible to add
+edges to an existing compilation graph in plugins without having to
+know about all tool definitions used in the graph.</p>
+<p>The default edges are assigned a weight of 1, and optional edges get a
+weight of 0 + 2*N where N is the number of tests that evaluated to
+true in the <tt class="docutils literal"><span class="pre">case</span></tt> expression. It is also possible to provide an
+integer 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,
+the weight is increased (or decreased) by the provided value instead
+of the default 2. It is also possible to change the default weight of
+an 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>
+construct.</p>
+<p>When passing an input file through the graph, LLVMC picks the edge
+with the maximum weight. To avoid ambiguity, there should be only one
+default edge between two nodes (with the exception of the root node,
+which gets a special treatment - there you are allowed to specify one
+default edge <em>per language</em>).</p>
+<p>When multiple plugins are loaded, their compilation graphs are merged
+together. Since multiple edges that have the same end nodes are not
+allowed (i.e. the graph is not a multigraph), an edge defined in
+several plugins will be replaced by the definition from the plugin
+that was loaded last. Plugin load order can be controlled by using the
+plugin priority feature described above.</p>
+<p>To get a visual representation of the compilation graph (useful for
+debugging), 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
+<tt class="docutils literal"><span class="pre">gsview</span></tt> installed for this to work properly.</p>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="actions"></a>Actions</div>
-<div class="doc_text">
- <p>An action, with regard to <tt>llvmc</tt> is a basic operation that it takes
- in order to fulfill the user's request. Each phase of compilation will invoke
- zero or more actions in order to accomplish that phase.</p>
- <p>Actions come in two forms:</p>
- <ul>
- <li>Invokable Executables</li>
- <li>Functions in a shared library</li>
- </ul>
+<div class="section" id="describing-options">
+<h1><a class="toc-backref" href="#id10">Describing options</a></h1>
+<p>Command-line options that the plugin supports are defined by using an
+<tt class="docutils literal"><span class="pre">OptionList</span></tt>:</p>
+<pre class="literal-block">
+def Options : OptionList<[
+(switch_option "E", (help "Help string")),
+(alias_option "quiet", "q")
+...
+]>;
+</pre>
+<p>As you can see, the option list is just a list of DAGs, where each DAG
+is an option description consisting of the option name and some
+properties. A plugin can define more than one option list (they are
+all merged together in the end), which can be handy if one wants to
+separate option groups syntactically.</p>
+<ul>
+<li><p class="first">Possible option types:</p>
+<blockquote>
+<ul class="simple">
+<li><tt class="docutils literal"><span class="pre">switch_option</span></tt> - a simple boolean switch without arguments, for example
+<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>
+<li><tt class="docutils literal"><span class="pre">parameter_option</span></tt> - option that takes one argument, for example
+<tt class="docutils literal"><span class="pre">-std=c99</span></tt>. It is also allowed to use spaces instead of the equality
+sign: <tt class="docutils literal"><span class="pre">-std</span> <span class="pre">c99</span></tt>. At most one occurrence is allowed.</li>
+<li><tt class="docutils literal"><span class="pre">parameter_list_option</span></tt> - same as the above, but more than one option
+occurence is allowed.</li>
+<li><tt class="docutils literal"><span class="pre">prefix_option</span></tt> - same as the parameter_option, but the option name and
+argument do not have to be separated. Example: <tt class="docutils literal"><span class="pre">-ofile</span></tt>. This can be also
+specified 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
+(<tt class="docutils literal"><span class="pre">=file</span></tt> will be interpreted as option value). At most one occurrence is
+allowed.</li>
+<li><tt class="docutils literal"><span class="pre">prefix_list_option</span></tt> - same as the above, but more than one occurence of
+the option is allowed; example: <tt class="docutils literal"><span class="pre">-lm</span> <span class="pre">-lpthread</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">alias_option</span></tt> - a special option type for creating aliases. Unlike other
+option types, aliases are not allowed to have any properties besides the
+aliased option name. Usage example: <tt class="docutils literal"><span class="pre">(alias_option</span> <span class="pre">"preprocess",</span> <span class="pre">"E")</span></tt></li>
+</ul>
+</blockquote>
+</li>
+<li><p class="first">Possible option properties:</p>
+<blockquote>
+<ul class="simple">
+<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>
+output.</li>
+<li><tt class="docutils literal"><span class="pre">required</span></tt> - this option must be specified exactly once (or, in case of
+the list options without the <tt class="docutils literal"><span class="pre">multi_val</span></tt> property, at least
+once). 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>
+<li><tt class="docutils literal"><span class="pre">one_or_more</span></tt> - the option must be specified at least one time. Useful
+only for list options in conjunction with <tt class="docutils literal"><span class="pre">multi_val</span></tt>; for ordinary lists
+it 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
+<tt class="docutils literal"><span class="pre">zero_or_one</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">zero_or_one</span></tt> - the option can be specified zero or one times. Useful
+only for list options in conjunction with <tt class="docutils literal"><span class="pre">multi_val</span></tt>. Incompatible with
+<tt class="docutils literal"><span class="pre">required</span></tt> and <tt class="docutils literal"><span class="pre">one_or_more</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">hidden</span></tt> - the description of this option will not appear in
+the <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>
+output).</li>
+<li><tt class="docutils literal"><span class="pre">really_hidden</span></tt> - the option will not be mentioned in any help
+output.</li>
+<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
+special cases). Usage example: <tt class="docutils literal"><span class="pre">(parameter_list_option</span> <span class="pre">"foo",</span> <span class="pre">(multi_val</span>
+<span class="pre">3))</span></tt>. Only list options can have this attribute; you can, however, use
+the <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>
+<li><tt class="docutils literal"><span class="pre">extern</span></tt> - this option is defined in some other plugin, see below.</li>
+</ul>
+</blockquote>
+</li>
+</ul>
+<div class="section" id="external-options">
+<h2><a class="toc-backref" href="#id11">External options</a></h2>
+<p>Sometimes, when linking several plugins together, one plugin needs to
+access options defined in some other plugin. Because of the way
+options are implemented, such options must be marked as
+<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
+for. Example:</p>
+<pre class="literal-block">
+...
+(switch_option "E", (extern))
+...
+</pre>
+<p>See also the section on plugin <a class="reference internal" href="#priorities">priorities</a>.</p>
</div>
-
-<!-- *********************************************************************** -->
-<div class="doc_section"><a name="configuration">Configuration</a></div>
-<!-- *********************************************************************** -->
-<div class="doc_text">
- <p>This section of the document describes the configuration files used by
- <tt>llvmc</tt>. Configuration information is relatively static for a
- given release of LLVM and a compiler tool. However, the details may
- change from release to release of either. Users are encouraged to simply use
- the various options of the <tt>llvmc</tt> command and ignore the configuration
- of the tool. These configuration files are for compiler writers and LLVM
- developers. Those wishing to simply use <tt>llvmc</tt> don't need to understand
- this section but it may be instructive on how the tool works.</p>
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="overview"></a>Overview</div>
-<div class="doc_text">
-<p><tt>llvmc</tt> is highly configurable both on the command line and in
-configuration files. The options it understands are generic, consistent and
-simple by design. Furthermore, the <tt>llvmc</tt> options apply to the
-compilation of any LLVM enabled programming language. To be enabled as a
-supported source language compiler, a compiler writer must provide a
-configuration file that tells <tt>llvmc</tt> how to invoke the compiler
-and what its capabilities are. The purpose of the configuration files then
-is to allow compiler writers to specify to <tt>llvmc</tt> how the compiler
-should be invoked. Users may but are not advised to alter the compiler's
-<tt>llvmc</tt> configuration.</p>
-
-<p>Because <tt>llvmc</tt> just invokes other programs, it must deal with the
-available command line options for those programs regardless of whether they
-were written for LLVM or not. Furthermore, not all compiler tools will
-have the same capabilities. Some compiler tools will simply generate LLVM assembly
-code, others will be able to generate fully optimized bitcode. In general,
-<tt>llvmc</tt> doesn't make any assumptions about the capabilities or command
-line options of a sub-tool. It simply uses the details found in the
-configuration files and leaves it to the compiler writer to specify the
-configuration correctly.</p>
-
-<p>This approach means that new compiler tools can be up and working very
-quickly. As a first cut, a tool can simply compile its source to raw
-(unoptimized) bitcode or LLVM assembly and <tt>llvmc</tt> can be configured
-to pick up the slack (translate LLVM assembly to bitcode, optimize the
-bitcode, generate native assembly, link, etc.). In fact, the compiler tools
-need not use any LLVM libraries, and it could be written in any language
-(instead of C++). The configuration data will allow the full range of
-optimization, assembly, and linking capabilities that LLVM provides to be added
-to these kinds of tools. Enabling the rapid development of front-ends is one
-of the primary goals of <tt>llvmc</tt>.</p>
-
-<p>As a compiler tool matures, it may utilize the LLVM libraries and tools
-to more efficiently produce optimized bitcode directly in a single compilation
-and optimization program. In these cases, multiple tools would not be needed
-and the configuration data for the compiler would change.</p>
-
-<p>Configuring <tt>llvmc</tt> to the needs and capabilities of a source language
-compiler is relatively straight-forward. A compiler writer must provide a
-definition of what to do for each of the five compilation phases for each of
-the optimization levels. The specification consists simply of prototypical
-command lines into which <tt>llvmc</tt> can substitute command line
-arguments and file names. Note that any given phase can be completely blank if
-the source language's compiler combines multiple phases into a single program.
-For example, quite often pre-processing, translation, and optimization are
-combined into a single program. The specification for such a compiler would have
-blank entries for pre-processing and translation but a full command line for
-optimization.</p>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="filetypes">Configuration Files</a></div>
-<div class="doc_subsubsection"><a name="filecontents">File Contents</a></div>
-<div class="doc_text">
- <p>Each configuration file provides the details for a single source language
- that is to be compiled. This configuration information tells <tt>llvmc</tt>
- how to invoke the language's pre-processor, translator, optimizer, assembler
- and linker. Note that a given source language needn't provide all these tools
- as many of them exist in llvm currently.</p>
+<div class="section" id="conditional-evaluation">
+<span id="case"></span><h1><a class="toc-backref" href="#id12">Conditional evaluation</a></h1>
+<p>The 'case' construct is the main means by which programmability is
+achieved in LLVMC. It can be used to calculate edge weights, program
+actions and modify the shell commands to be executed. The 'case'
+expression is designed after the similarly-named construct in
+functional 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>
+<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
+are evaluated only if the corresponding tests evaluate to true.</p>
+<p>Examples:</p>
+<pre class="literal-block">
+// Edge weight calculation
+
+// Increases edge weight by 5 if "-A" is provided on the
+// command-line, and by 5 more if "-B" is also provided.
+(case
+ (switch_on "A"), (inc_weight 5),
+ (switch_on "B"), (inc_weight 5))
+
+
+// Tool command line specification
+
+// Evaluates to "cmdline1" if the option "-A" is provided on the
+// command line; to "cmdline2" if "-B" is provided;
+// otherwise to "cmdline3".
+
+(case
+ (switch_on "A"), "cmdline1",
+ (switch_on "B"), "cmdline2",
+ (default), "cmdline3")
+</pre>
+<p>Note the slight difference in 'case' expression handling in contexts
+of edge weights and command line specification - in the second example
+the value of the <tt class="docutils literal"><span class="pre">"B"</span></tt> switch is never checked when switch <tt class="docutils literal"><span class="pre">"A"</span></tt> is
+enabled, and the whole expression always evaluates to <tt class="docutils literal"><span class="pre">"cmdline1"</span></tt> in
+that case.</p>
+<p>Case expressions can also be nested, i.e. the following is legal:</p>
+<pre class="literal-block">
+(case (switch_on "E"), (case (switch_on "o"), ..., (default), ...)
+ (default), ...)
+</pre>
+<p>You should, however, try to avoid doing that because it hurts
+readability. It is usually better to split tool descriptions and/or
+use TableGen inheritance instead.</p>
+<ul class="simple">
+<li>Possible tests are:<ul>
+<li><tt class="docutils literal"><span class="pre">switch_on</span></tt> - Returns true if a given command-line switch is
+provided by the user. Example: <tt class="docutils literal"><span class="pre">(switch_on</span> <span class="pre">"opt")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">parameter_equals</span></tt> - Returns true if a command-line parameter equals
+a given value.
+Example: <tt class="docutils literal"><span class="pre">(parameter_equals</span> <span class="pre">"W",</span> <span class="pre">"all")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">element_in_list</span></tt> - Returns true if a command-line parameter
+list contains a given value.
+Example: <tt class="docutils literal"><span class="pre">(parameter_in_list</span> <span class="pre">"l",</span> <span class="pre">"pthread")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">input_languages_contain</span></tt> - Returns true if a given language
+belongs to the current input language set.
+Example: <tt class="docutils literal"><span class="pre">(input_languages_contain</span> <span class="pre">"c++")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">in_language</span></tt> - Evaluates to true if the input file language
+equals to the argument. At the moment works only with <tt class="docutils literal"><span class="pre">cmd_line</span></tt>
+and <tt class="docutils literal"><span class="pre">actions</span></tt> (on non-join nodes).
+Example: <tt class="docutils literal"><span class="pre">(in_language</span> <span class="pre">"c++")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">not_empty</span></tt> - Returns true if a given option (which should be
+either a parameter or a parameter list) is set by the
+user.
+Example: <tt class="docutils literal"><span class="pre">(not_empty</span> <span class="pre">"o")</span></tt>.</li>
+<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>
+<span class="pre">X))</span></tt>. Provided for convenience.</li>
+<li><tt class="docutils literal"><span class="pre">default</span></tt> - Always evaluates to true. Should always be the last
+test in the <tt class="docutils literal"><span class="pre">case</span></tt> expression.</li>
+<li><tt class="docutils literal"><span class="pre">and</span></tt> - A standard logical combinator that returns true iff all
+of its arguments return true. Used like this: <tt class="docutils literal"><span class="pre">(and</span> <span class="pre">(test1),</span>
+<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,
+but not encouraged.</li>
+<li><tt class="docutils literal"><span class="pre">or</span></tt> - Another logical combinator that returns true only if any
+one of its arguments returns true. Example: <tt class="docutils literal"><span class="pre">(or</span> <span class="pre">(test1),</span>
+<span class="pre">(test2),</span> <span class="pre">...</span> <span class="pre">(testN))</span></tt>.</li>
+</ul>
+</li>
+</ul>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection"><a name="dirsearch">Directory Search</a></div>
-<div class="doc_text">
- <p><tt>llvmc</tt> always looks for files of a specific name. It uses the
- first file with the name its looking for by searching directories in the
- following order:<br/>
- <ol>
- <li>Any directory specified by the <tt>-config-dir</tt> option will be
- checked first.</li>
- <li>If the environment variable LLVM_CONFIG_DIR is set, and it contains
- the name of a valid directory, that directory will be searched next.</li>
- <li>If the user's home directory (typically <tt>/home/user</tt> contains
- a sub-directory named <tt>.llvm</tt> and that directory contains a
- sub-directory named <tt>etc</tt> then that directory will be tried
- next.</li>
- <li>If the LLVM installation directory (typically <tt>/usr/local/llvm</tt>
- contains a sub-directory named <tt>etc</tt> then that directory will be
- tried last.</li>
- <li>A standard "system" directory will be searched next. This is typically
- <tt>/etc/llvm</tt> on UNIX™ and <tt>C:\WINNT</tt> on Microsoft
- Windows™.</li>
- <li>If the configuration file sought still can't be found, <tt>llvmc</tt>
- will print an error message and exit.</li>
- </ol>
- <p>The first file found in this search will be used. Other files with the
- same name will be ignored even if they exist in one of the subsequent search
- locations.</p>
+<div class="section" id="writing-a-tool-description">
+<h1><a class="toc-backref" href="#id13">Writing a tool description</a></h1>
+<p>As was said earlier, nodes in the compilation graph represent tools,
+which are described separately. A tool definition looks like this
+(taken from the <tt class="docutils literal"><span class="pre">include/llvm/CompilerDriver/Tools.td</span></tt> file):</p>
+<pre class="literal-block">
+def llvm_gcc_cpp : Tool<[
+ (in_language "c++"),
+ (out_language "llvm-assembler"),
+ (output_suffix "bc"),
+ (cmd_line "llvm-g++ -c $INFILE -o $OUTFILE -emit-llvm"),
+ (sink)
+ ]>;
+</pre>
+<p>This defines a new tool called <tt class="docutils literal"><span class="pre">llvm_gcc_cpp</span></tt>, which is an alias for
+<tt class="docutils literal"><span class="pre">llvm-g++</span></tt>. As you can see, a tool definition is just a list of
+properties; most of them should be self-explanatory. The <tt class="docutils literal"><span class="pre">sink</span></tt>
+property means that this tool should be passed all command-line
+options that aren't mentioned in the option list.</p>
+<p>The complete list of all currently implemented tool properties follows.</p>
+<ul class="simple">
+<li>Possible tool properties:<ul>
+<li><tt class="docutils literal"><span class="pre">in_language</span></tt> - input language name. Can be either a string or a
+list, in case the tool supports multiple input languages.</li>
+<li><tt class="docutils literal"><span class="pre">out_language</span></tt> - output language name. Tools are not allowed to
+have multiple output languages.</li>
+<li><tt class="docutils literal"><span class="pre">output_suffix</span></tt> - output file suffix. Can also be changed
+dynamically, see documentation on actions.</li>
+<li><tt class="docutils literal"><span class="pre">cmd_line</span></tt> - the actual command used to run the tool. You can
+use <tt class="docutils literal"><span class="pre">$INFILE</span></tt> and <tt class="docutils literal"><span class="pre">$OUTFILE</span></tt> variables, output redirection
+with <tt class="docutils literal"><span class="pre">></span></tt>, hook invocations (<tt class="docutils literal"><span class="pre">$CALL</span></tt>), environment variables
+(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>
+<li><tt class="docutils literal"><span class="pre">join</span></tt> - this tool is a "join node" in the graph, i.e. it gets a
+list of input files and joins them together. Used for linkers.</li>
+<li><tt class="docutils literal"><span class="pre">sink</span></tt> - all command-line options that are not handled by other
+tools are passed to this tool.</li>
+<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
+this tool reacts on command-line options (described in more detail
+below).</li>
+</ul>
+</li>
+</ul>
+<div class="section" id="actions">
+<h2><a class="toc-backref" href="#id14">Actions</a></h2>
+<p>A tool often needs to react to command-line options, and this is
+precisely what the <tt class="docutils literal"><span class="pre">actions</span></tt> property is for. The next example
+illustrates this feature:</p>
+<pre class="literal-block">
+def llvm_gcc_linker : Tool<[
+ (in_language "object-code"),
+ (out_language "executable"),
+ (output_suffix "out"),
+ (cmd_line "llvm-gcc $INFILE -o $OUTFILE"),
+ (join),
+ (actions (case (not_empty "L"), (forward "L"),
+ (not_empty "l"), (forward "l"),
+ (not_empty "dummy"),
+ [(append_cmd "-dummy1"), (append_cmd "-dummy2")])
+ ]>;
+</pre>
+<p>The <tt class="docutils literal"><span class="pre">actions</span></tt> tool property is implemented on top of the omnipresent
+<tt class="docutils literal"><span class="pre">case</span></tt> expression. It associates one or more different <em>actions</em>
+with given conditions - in the example, the actions are <tt class="docutils literal"><span class="pre">forward</span></tt>,
+which forwards a given option unchanged, and <tt class="docutils literal"><span class="pre">append_cmd</span></tt>, which
+appends a given string to the tool execution command. Multiple actions
+can be associated with a single condition by using a list of actions
+(used in the example to append some dummy options). The same <tt class="docutils literal"><span class="pre">case</span></tt>
+construct can also be used in the <tt class="docutils literal"><span class="pre">cmd_line</span></tt> property to modify the
+tool command line.</p>
+<p>The "join" property used in the example means that this tool behaves
+like a linker.</p>
+<p>The list of all possible actions follows.</p>
+<ul>
+<li><p class="first">Possible actions:</p>
+<blockquote>
+<ul class="simple">
+<li><tt class="docutils literal"><span class="pre">append_cmd</span></tt> - append a string to the tool invocation
+command.
+Example: <tt class="docutils literal"><span class="pre">(case</span> <span class="pre">(switch_on</span> <span class="pre">"pthread"),</span> <span class="pre">(append_cmd</span>
+<span class="pre">"-lpthread"))</span></tt></li>
+<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>
+<span class="pre">Example:</span> <span class="pre">``(error</span> <span class="pre">"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!")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">forward</span></tt> - forward an option unchanged.
+Example: <tt class="docutils literal"><span class="pre">(forward</span> <span class="pre">"Wall")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">forward_as</span></tt> - Change the name of an option, but forward the
+argument unchanged.
+Example: <tt class="docutils literal"><span class="pre">(forward_as</span> <span class="pre">"O0",</span> <span class="pre">"--disable-optimization")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">output_suffix</span></tt> - modify the output suffix of this
+tool.
+Example: <tt class="docutils literal"><span class="pre">(output_suffix</span> <span class="pre">"i")</span></tt>.</li>
+<li><tt class="docutils literal"><span class="pre">stop_compilation</span></tt> - stop compilation after this tool processes
+its input. Used without arguments.</li>
+<li><tt class="docutils literal"><span class="pre">unpack_values</span></tt> - used for for splitting and forwarding
+comma-separated lists of options, e.g. <tt class="docutils literal"><span class="pre">-Wa,-foo=bar,-baz</span></tt> is
+converted to <tt class="docutils literal"><span class="pre">-foo=bar</span> <span class="pre">-baz</span></tt> and appended to the tool invocation
+command.
+Example: <tt class="docutils literal"><span class="pre">(unpack_values</span> <span class="pre">"Wa,")</span></tt>.</li>
+</ul>
+</blockquote>
+</li>
+</ul>
</div>
-
-<div class="doc_subsubsection"><a name="filenames">File Names</a></div>
-<div class="doc_text">
- <p>In the directories searched, each configuration file is given a specific
- name to foster faster lookup (so llvmc doesn't have to do directory searches).
- The name of a given language specific configuration file is simply the same
- as the suffix used to identify files containing source in that language.
- For example, a configuration file for C++ source might be named
- <tt>cpp</tt>, <tt>C</tt>, or <tt>cxx</tt>. For languages that support multiple
- file suffixes, multiple (probably identical) files (or symbolic links) will
- need to be provided.</p>
</div>
-
-<div class="doc_subsubsection"><a name="whatgetsread">What Gets Read</a></div>
-<div class="doc_text">
- <p>Which configuration files are read depends on the command line options and
- the suffixes of the file names provided on <tt>llvmc</tt>'s command line. Note
- that the <tt>-x LANGUAGE</tt> option alters the language that <tt>llvmc</tt>
- uses for the subsequent files on the command line. Only the configuration
- files actually needed to complete <tt>llvmc</tt>'s task are read. Other
- language specific files will be ignored.</p>
+<div class="section" id="language-map">
+<h1><a class="toc-backref" href="#id15">Language map</a></h1>
+<p>If you are adding support for a new language to LLVMC, you'll need to
+modify the language map, which defines mappings from file extensions
+to language names. It is used to choose the proper toolchain(s) for a
+given input file set. Language map definition looks like this:</p>
+<pre class="literal-block">
+def LanguageMap : LanguageMap<
+ [LangToSuffixes<"c++", ["cc", "cp", "cxx", "cpp", "CPP", "c++", "C"]>,
+ LangToSuffixes<"c", ["c"]>,
+ ...
+ ]>;
+</pre>
+<p>For example, without those definitions the following command wouldn't work:</p>
+<pre class="literal-block">
+$ llvmc hello.cpp
+llvmc: Unknown suffix: cpp
+</pre>
+<p>The language map entries should be added only for tools that are
+linked with the root node. Since tools are not allowed to have
+multiple output languages, for nodes "inside" the graph the input and
+output languages should match. This is enforced at compile-time.</p>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="syntax"></a>Syntax</div>
-<div class="doc_text">
- <p>The syntax of the configuration files is very simple and somewhat
- compatible with Java's property files. Here are the syntax rules:</p>
- <ul>
- <li>The file encoding is ASCII.</li>
- <li>The file is line oriented. There should be one configuration definition
- per line. Lines are terminated by the newline (0x0A) and/or carriage return
- characters (0x0D)</li>
- <li>A backslash (<tt>\</tt>) before a newline causes the newline to be
- ignored. This is useful for line continuation of long definitions. A
- backslash anywhere else is recognized as a backslash.</li>
- <li>A configuration item consists of a name, an <tt>=</tt> and a value.</li>
- <li>A name consists of a sequence of identifiers separated by period.</li>
- <li>An identifier consists of specific keywords made up of only lower case
- and upper case letters (e.g. <tt>lang.name</tt>).</li>
- <li>Values come in four flavors: booleans, integers, commands and
- strings.</li>
- <li>Valid "false" boolean values are <tt>false False FALSE no No NO
- off Off</tt> and <tt>OFF</tt>.</li>
- <li>Valid "true" boolean values are <tt>true True TRUE yes Yes YES
- on On</tt> and <tt>ON</tt>.</li>
- <li>Integers are simply sequences of digits.</li>
- <li>Commands start with a program name and are followed by a sequence of
- words that are passed to that program as command line arguments. Program
- arguments that begin and end with the <tt>%</tt> sign will have their value
- substituted. Program names beginning with <tt>/</tt> are considered to be
- absolute. Otherwise the <tt>PATH</tt> will be applied to find the program to
- execute.</li>
- <li>Strings are composed of multiple sequences of characters from the
- character class <tt>[-A-Za-z0-9_:%+/\\|,]</tt> separated by white
- space.</li>
- <li>White space on a line is folded. Multiple blanks or tabs will be
- reduced to a single blank.</li>
- <li>White space before the configuration item's name is ignored.</li>
- <li>White space on either side of the <tt>=</tt> is ignored.</li>
- <li>White space in a string value is used to separate the individual
- components of the string value but otherwise ignored.</li>
- <li>Comments are introduced by the <tt>#</tt> character. Everything after a
- <tt>#</tt> and before the end of line is ignored.</li>
- </ul>
+<div class="section" id="more-advanced-topics">
+<h1><a class="toc-backref" href="#id16">More advanced topics</a></h1>
+<div class="section" id="hooks-and-environment-variables">
+<span id="hooks"></span><h2><a class="toc-backref" href="#id17">Hooks and environment variables</a></h2>
+<p>Normally, LLVMC executes programs from the system <tt class="docutils literal"><span class="pre">PATH</span></tt>. Sometimes,
+this is not sufficient: for example, we may want to specify tool paths
+or names in the configuration file. This can be easily achieved via
+the hooks mechanism. To write your own hooks, just add their
+definitions 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
+your plugin directory. Hooks should live in the <tt class="docutils literal"><span class="pre">hooks</span></tt> namespace
+and 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>
+<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
+<tt class="docutils literal"><span class="pre">cmd_line</span></tt> tool property:</p>
+<pre class="literal-block">
+(cmd_line "$CALL(MyHook)/path/to/file -o $CALL(AnotherHook)")
+</pre>
+<p>To pass arguments to hooks, use the following syntax:</p>
+<pre class="literal-block">
+(cmd_line "$CALL(MyHook, 'Arg1', 'Arg2', 'Arg # 3')/path/to/file -o1 -o2")
+</pre>
+<p>It is also possible to use environment variables in the same manner:</p>
+<pre class="literal-block">
+(cmd_line "$ENV(VAR1)/path/to/file -o $ENV(VAR2)")
+</pre>
+<p>To change the command line string based on user-provided options use
+the <tt class="docutils literal"><span class="pre">case</span></tt> expression (documented <a class="reference internal" href="#case">above</a>):</p>
+<pre class="literal-block">
+(cmd_line
+ (case
+ (switch_on "E"),
+ "llvm-g++ -E -x c $INFILE -o $OUTFILE",
+ (default),
+ "llvm-g++ -c -x c $INFILE -o $OUTFILE -emit-llvm"))
+</pre>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="items">Configuration Items</a></div>
-<div class="doc_text">
- <p>The table below provides definitions of the allowed configuration items
- that may appear in a configuration file. Every item has a default value and
- does not need to appear in the configuration file. Missing items will have the
- default value. Each identifier may appear as all lower case, first letter
- capitalized or all upper case.</p>
- <table>
- <tbody>
- <tr>
- <th>Name</th>
- <th>Value Type</th>
- <th>Description</th>
- <th>Default</th>
- </tr>
- <tr><td colspan="4"><h4>LLVMC ITEMS</h4></td></tr>
- <tr>
- <td><b>version</b></td>
- <td>string</td>
- <td class="td_left">Provides the version string for the contents of this
- configuration file. What is accepted as a legal configuration file
- will change over time and this item tells <tt>llvmc</tt> which version
- should be expected.</td>
- <td><i>b</i></td>
- </tr>
- <tr><td colspan="4"><h4>LANG ITEMS</h4></td></tr>
- <tr>
- <td><b>lang.name</b></td>
- <td>string</td>
- <td class="td_left">Provides the common name for a language definition.
- For example "C++", "Pascal", "FORTRAN", etc.</td>
- <td><i>blank</i></td>
- </tr>
- <tr>
- <td><b>lang.opt1</b></td>
- <td>string</td>
- <td class="td_left">Specifies the parameters to give the optimizer when
- <tt>-O1</tt> is specified on the <tt>llvmc</tt> command line.</td>
- <td><tt>-simplifycfg -instcombine -mem2reg</tt></td>
- </tr>
- <tr>
- <td><b>lang.opt2</b></td>
- <td>string</td>
- <td class="td_left">Specifies the parameters to give the optimizer when
- <tt>-O2</tt> is specified on the <tt>llvmc</tt> command line.</td>
- <td><i>TBD</i></td>
- </tr>
- <tr>
- <td><b>lang.opt3</b></td>
- <td>string</td>
- <td class="td_left">Specifies the parameters to give the optimizer when
- <tt>-O3</tt> is specified on the <tt>llvmc</tt> command line.</td>
- <td><i>TBD</i></td>
- </tr>
- <tr>
- <td><b>lang.opt4</b></td>
- <td>string</td>
- <td class="td_left">Specifies the parameters to give the optimizer when
- <tt>-O4</tt> is specified on the <tt>llvmc</tt> command line.</td>
- <td><i>TBD</i></td>
- </tr>
- <tr>
- <td><b>lang.opt5</b></td>
- <td>string</td>
- <td class="td_left">Specifies the parameters to give the optimizer when
- <tt>-O5</tt> is specified on the <tt>llvmc</tt> command line.</td>
- <td><i>TBD</i></td>
- </tr>
- <tr><td colspan="4"><h4>PREPROCESSOR ITEMS</h4></td></tr>
- <tr>
- <td><b>preprocessor.command</b></td>
- <td>command</td>
- <td class="td_left">This provides the command prototype that will be used
- to run the preprocessor. This is generally only used with the
- <tt>-E</tt> option.</td>
- <td><blank></td>
- </tr>
- <tr>
- <td><b>preprocessor.required</b></td>
- <td>boolean</td>
- <td class="td_left">This item specifies whether the pre-processing phase
- is required by the language. If the value is true, then the
- <tt>preprocessor.command</tt> value must not be blank. With this option,
- <tt>llvmc</tt> will always run the preprocessor as it assumes that the
- translation and optimization phases don't know how to pre-process their
- input.</td>
- <td>false</td>
- </tr>
- <tr><td colspan="4"><h4>TRANSLATOR ITEMS</h4></td></tr>
- <tr>
- <td><b>translator.command</b></td>
- <td>command</td>
- <td class="td_left">This provides the command prototype that will be used
- to run the translator. Valid substitutions are <tt>%in%</tt> for the
- input file and <tt>%out%</tt> for the output file.</td>
- <td><blank></td>
- </tr>
- <tr>
- <td><b>translator.output</b></td>
- <td><tt>bitcode</tt> or <tt>assembly</tt></td>
- <td class="td_left">This item specifies the kind of output the language's
- translator generates.</td>
- <td><tt>bitcode</tt></td>
- </tr>
- <tr>
- <td><b>translator.preprocesses</b></td>
- <td>boolean</td>
- <td class="td_left">Indicates that the translator also preprocesses. If
- this is true, then <tt>llvmc</tt> will skip the pre-processing phase
- whenever the final phase is not pre-processing.</td>
- <td><tt>false</tt></td>
- </tr>
- <tr><td colspan="4"><h4>OPTIMIZER ITEMS</h4></td></tr>
- <tr>
- <td><b>optimizer.command</b></td>
- <td>command</td>
- <td class="td_left">This provides the command prototype that will be used
- to run the optimizer. Valid substitutions are <tt>%in%</tt> for the
- input file and <tt>%out%</tt> for the output file.</td>
- <td><blank></td>
- </tr>
- <tr>
- <td><b>optimizer.output</b></td>
- <td><tt>bitcode</tt> or <tt>assembly</tt></td>
- <td class="td_left">This item specifies the kind of output the language's
- optimizer generates. Valid values are "assembly" and "bitcode"</td>
- <td><tt>bitcode</tt></td>
- </tr>
- <tr>
- <td><b>optimizer.preprocesses</b></td>
- <td>boolean</td>
- <td class="td_left">Indicates that the optimizer also preprocesses. If
- this is true, then <tt>llvmc</tt> will skip the pre-processing phase
- whenever the final phase is optimization or later.</td>
- <td><tt>false</tt></td>
- </tr>
- <tr>
- <td><b>optimizer.translates</b></td>
- <td>boolean</td>
- <td class="td_left">Indicates that the optimizer also translates. If
- this is true, then <tt>llvmc</tt> will skip the translation phase
- whenever the final phase is optimization or later.</td>
- <td><tt>false</tt></td>
- </tr>
- <tr><td colspan="4"><h4>ASSEMBLER ITEMS</h4></td></tr>
- <tr>
- <td><b>assembler.command</b></td>
- <td>command</td>
- <td class="td_left">This provides the command prototype that will be used
- to run the assembler. Valid substitutions are <tt>%in%</tt> for the
- input file and <tt>%out%</tt> for the output file.</td>
- <td><blank></td>
- </tr>
- </tbody>
- </table>
+<div class="section" id="how-plugins-are-loaded">
+<span id="priorities"></span><h2><a class="toc-backref" href="#id18">How plugins are loaded</a></h2>
+<p>It is possible for LLVMC plugins to depend on each other. For example,
+one can create edges between nodes defined in some other plugin. To
+make this work, however, that plugin should be loaded first. To
+achieve this, the concept of plugin priority was introduced. By
+default, every plugin has priority zero; to specify the priority
+explicitly, put the following line in your plugin's TableGen file:</p>
+<pre class="literal-block">
+def Priority : PluginPriority<$PRIORITY_VALUE>;
+# Where PRIORITY_VALUE is some integer > 0
+</pre>
+<p>Plugins are loaded in order of their (increasing) priority, starting
+with 0. Therefore, the plugin with the highest priority value will be
+loaded last.</p>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="substitutions">Substitutions</a></div>
-<div class="doc_text">
- <p>On any configuration item that ends in <tt>command</tt>, you must
- specify substitution tokens. Substitution tokens begin and end with a percent
- sign (<tt>%</tt>) and are replaced by the corresponding text. Any substitution
- token may be given on any <tt>command</tt> line but some are more useful than
- others. In particular each command <em>should</em> have both an <tt>%in%</tt>
- and an <tt>%out%</tt> substitution. The table below provides definitions of
- each of the allowed substitution tokens.</p>
- <table>
- <tbody>
- <tr>
- <th>Substitution Token</th>
- <th>Replacement Description</th>
- </tr>
- <tr>
- <td><tt>%args%</tt></td>
- <td class="td_left">Replaced with all the tool-specific arguments given
- to <tt>llvmc</tt> via the <tt>-T</tt> set of options. This just allows
- you to place these arguments in the correct place on the command line.
- If the <tt>%args%</tt> option does not appear on your command line,
- then you are explicitly disallowing the <tt>-T</tt> option for your
- tool.
- </td>
- <tr>
- <td><tt>%force%</tt></td>
- <td class="td_left">Replaced with the <tt>-f</tt> option if it was
- specified on the <tt>llvmc</tt> command line. This is intended to tell
- the compiler tool to force the overwrite of output files.
- </td>
- </tr>
- <tr>
- <td><tt>%in%</tt></td>
- <td class="td_left">Replaced with the full path of the input file. You
- needn't worry about the cascading of file names. <tt>llvmc</tt> will
- create temporary files and ensure that the output of one phase is the
- input to the next phase.</td>
- </tr>
- <tr>
- <td><tt>%opt%</tt></td>
- <td class="td_left">Replaced with the optimization options for the
- tool. If the tool understands the <tt>-O</tt> options then that will
- be passed. Otherwise, the <tt>lang.optN</tt> series of configuration
- items will specify which arguments are to be given.</td>
- </tr>
- <tr>
- <td><tt>%out%</tt></td>
- <td class="td_left">Replaced with the full path of the output file.
- Note that this is not necessarily the output file specified with the
- <tt>-o</tt> option on <tt>llvmc</tt>'s command line. It might be a
- temporary file that will be passed to a subsequent phase's input.
- </td>
- </tr>
- <tr>
- <td><tt>%stats%</tt></td>
- <td class="td_left">If your command accepts the <tt>-stats</tt> option,
- use this substitution token. If the user requested <tt>-stats</tt>
- from the <tt>llvmc</tt> command line then this token will be replaced
- with <tt>-stats</tt>, otherwise it will be ignored.
- </td>
- </tr>
- <tr>
- <td><tt>%target%</tt></td>
- <td class="td_left">Replaced with the name of the target "machine" for
- which code should be generated. The value used here is taken from the
- <tt>llvmc</tt> option <tt>-march</tt>.
- </td>
- </tr>
- <tr>
- <td><tt>%time%</tt></td>
- <td class="td_left">If your command accepts the <tt>-time-passes</tt>
- option, use this substitution token. If the user requested
- <tt>-time-passes</tt> from the <tt>llvmc</tt> command line then this
- token will be replaced with <tt>-time-passes</tt>, otherwise it will
- be ignored.
- </td>
- </tr>
- </tbody>
- </table>
+<div class="section" id="debugging">
+<h2><a class="toc-backref" href="#id19">Debugging</a></h2>
+<p>When writing LLVMC plugins, it can be useful to get a visual view of
+the resulting compilation graph. This can be achieved via the command
+line 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
+<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
+creates a Graphviz source file (<tt class="docutils literal"><span class="pre">compilation-graph.dot</span></tt>) in the
+current directory.</p>
+<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
+compilation graph for common errors like mismatched output/input
+language names, multiple default edges and cycles. These checks can't
+be performed at compile-time because the plugins can load code
+dynamically. 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
+perform any compilation tasks and returns the number of encountered
+errors as its status code.</p>
+<hr />
+<address>
+<a href="http://jigsaw.w3.org/css-validator/check/referer">
+<img src="http://jigsaw.w3.org/css-validator/images/vcss-blue"
+ alt="Valid CSS" /></a>
+<a href="http://validator.w3.org/check?uri=referer">
+<img src="http://www.w3.org/Icons/valid-xhtml10-blue"
+ alt="Valid XHTML 1.0 Transitional"/></a>
+
+<a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a><br />
+<a href="http://llvm.org">LLVM Compiler Infrastructure</a><br />
+
+Last modified: $Date: 2008-12-11 11:34:48 -0600 (Thu, 11 Dec 2008) $
+</address></div>
</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsection"><a name="sample">Sample Config File</a></div>
-<div class="doc_text">
- <p>Since an example is always instructive, here's how the Stacker language
- configuration file looks.</p>
- <pre><tt>
-# Stacker Configuration File For llvmc
-
-##########################################################
-# Language definitions
-##########################################################
- lang.name=Stacker
- lang.opt1=-simplifycfg -instcombine -mem2reg
- lang.opt2=-simplifycfg -instcombine -mem2reg -load-vn \
- -gcse -dse -scalarrepl -sccp
- lang.opt3=-simplifycfg -instcombine -mem2reg -load-vn \
- -gcse -dse -scalarrepl -sccp -branch-combine -adce \
- -globaldce -inline -licm
- lang.opt4=-simplifycfg -instcombine -mem2reg -load-vn \
- -gcse -dse -scalarrepl -sccp -ipconstprop \
- -branch-combine -adce -globaldce -inline -licm
- lang.opt5=-simplifycfg -instcombine -mem2reg --load-vn \
- -gcse -dse scalarrepl -sccp -ipconstprop \
- -branch-combine -adce -globaldce -inline -licm \
- -block-placement
-
-##########################################################
-# Pre-processor definitions
-##########################################################
-
- # Stacker doesn't have a preprocessor but the following
- # allows the -E option to be supported
- preprocessor.command=cp %in% %out%
- preprocessor.required=false
-
-##########################################################
-# Translator definitions
-##########################################################
-
- # To compile stacker source, we just run the stacker
- # compiler with a default stack size of 2048 entries.
- translator.command=stkrc -s 2048 %in% -o %out% %time% \
- %stats% %force% %args%
-
- # stkrc doesn't preprocess but we set this to true so
- # that we don't run the cp command by default.
- translator.preprocesses=true
-
- # The translator is required to run.
- translator.required=true
-
- # stkrc doesn't handle the -On options
- translator.output=bitcode
-
-##########################################################
-# Optimizer definitions
-##########################################################
-
- # For optimization, we use the LLVM "opt" program
- optimizer.command=opt %in% -o %out% %opt% %time% %stats% \
- %force% %args%
-
- optimizer.required = true
-
- # opt doesn't translate
- optimizer.translates = no
-
- # opt doesn't preprocess
- optimizer.preprocesses=no
-
- # opt produces bitcode
- optimizer.output = bc
-
-##########################################################
-# Assembler definitions
-##########################################################
- assembler.command=llc %in% -o %out% %target% %time% %stats%
-</tt></pre>
-</div>
-
-<!-- *********************************************************************** -->
-<div class="doc_section"><a name="glossary">Glossary</a></div>
-<!-- *********************************************************************** -->
-<div class="doc_text">
- <p>This document uses precise terms in reference to the various artifacts and
- concepts related to compilation. The terms used throughout this document are
- defined below.</p>
- <dl>
- <dt><a name="def_assembly"><b>assembly</b></a></dt>
- <dd>A compilation <a href="#def_phase">phase</a> in which LLVM bitcode or
- LLVM assembly code is assembled to a native code format (either target
- specific aseembly language or the platform's native object file format).
- </dd>
-
- <dt><a name="def_compiler"><b>compiler</b></a></dt>
- <dd>Refers to any program that can be invoked by <tt>llvmc</tt> to accomplish
- the work of one or more compilation <a href="#def_phase">phases</a>.</dd>
-
- <dt><a name="def_driver"><b>driver</b></a></dt>
- <dd>Refers to <tt>llvmc</tt> itself.</dd>
-
- <dt><a name="def_linking"><b>linking</b></a></dt>
- <dd>A compilation <a href="#def_phase">phase</a> in which LLVM bitcode files
- and (optionally) native system libraries are combined to form a complete
- executable program.</dd>
-
- <dt><a name="def_optimization"><b>optimization</b></a></dt>
- <dd>A compilation <a href="#def_phase">phase</a> in which LLVM bitcode is
- optimized.</dd>
-
- <dt><a name="def_phase"><b>phase</b></a></dt>
- <dd>Refers to any one of the five compilation phases that that
- <tt>llvmc</tt> supports. The five phases are:
- <a href="#def_preprocessing">preprocessing</a>,
- <a href="#def_translation">translation</a>,
- <a href="#def_optimization">optimization</a>,
- <a href="#def_assembly">assembly</a>,
- <a href="#def_linking">linking</a>.</dd>
-
- <dt><a name="def_sourcelanguage"><b>source language</b></a></dt>
- <dd>Any common programming language (e.g. C, C++, Java, Stacker, ML,
- FORTRAN). These languages are distinguished from any of the lower level
- languages (such as LLVM or native assembly), by the fact that a
- <a href="#def_translation">translation</a> <a href="#def_phase">phase</a>
- is required before LLVM can be applied.</dd>
-
- <dt><a name="def_tool"><b>tool</b></a></dt>
- <dd>Refers to any program in the LLVM tool set.</dd>
-
- <dt><a name="def_translation"><b>translation</b></a></dt>
- <dd>A compilation <a href="#def_phase">phase</a> in which
- <a href="#def_sourcelanguage">source language</a> code is translated into
- either LLVM assembly language or LLVM bitcode.</dd>
- </dl>
</div>
-<!-- *********************************************************************** -->
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- href="mailto:rspencer@x10sys.com">Reid Spencer</a><br>
-<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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