mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-24 19:52:54 +01:00
126 lines
6.3 KiB
HTML
126 lines
6.3 KiB
HTML
<?xml version="1.0" encoding="utf-8" ?>
|
|
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
|
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
|
<meta name="generator" content="Docutils 0.6: http://docutils.sourceforge.net/" />
|
|
<title>Tutorial - Using LLVMC</title>
|
|
<link rel="stylesheet" href="llvm.css" type="text/css" />
|
|
</head>
|
|
<body>
|
|
<div class="document" id="tutorial-using-llvmc">
|
|
<h1 class="title">Tutorial - Using LLVMC</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="id1">Introduction</a></li>
|
|
<li><a class="reference internal" href="#using-the-llvmc-program" id="id2">Using the <tt class="docutils literal">llvmc</tt> program</a></li>
|
|
<li><a class="reference internal" href="#using-llvmc-to-generate-toolchain-drivers" id="id3">Using LLVMC to generate toolchain drivers</a></li>
|
|
</ul>
|
|
</div>
|
|
<div class="doc_author">
|
|
<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="#id1">Introduction</a></h1>
|
|
<p>LLVMC is a generic compiler driver, which plays the same role for LLVM as the
|
|
<tt class="docutils literal">gcc</tt> program does for GCC - the difference being that LLVMC is designed to be
|
|
more adaptable and easier to customize. Most of LLVMC functionality is
|
|
implemented via high-level TableGen code, from which a corresponding C++ source
|
|
file is automatically generated. This tutorial describes the basic usage and
|
|
configuration of LLVMC.</p>
|
|
</div>
|
|
<div class="section" id="using-the-llvmc-program">
|
|
<h1><a class="toc-backref" href="#id2">Using the <tt class="docutils literal">llvmc</tt> program</a></h1>
|
|
<p>In general, <tt class="docutils literal">llvmc</tt> tries to be command-line compatible with <tt class="docutils literal">gcc</tt> as much
|
|
as possible, so most of the familiar options work:</p>
|
|
<pre class="literal-block">
|
|
$ llvmc -O3 -Wall hello.cpp
|
|
$ ./a.out
|
|
hello
|
|
</pre>
|
|
<p>This will invoke <tt class="docutils literal"><span class="pre">llvm-g++</span></tt> under the hood (you can see which commands are
|
|
executed by using the <tt class="docutils literal"><span class="pre">-v</span></tt> option). For further help on command-line LLVMC
|
|
usage, refer to the <tt class="docutils literal">llvmc <span class="pre">--help</span></tt> output.</p>
|
|
</div>
|
|
<div class="section" id="using-llvmc-to-generate-toolchain-drivers">
|
|
<h1><a class="toc-backref" href="#id3">Using LLVMC to generate toolchain drivers</a></h1>
|
|
<p>LLVMC-based drivers are written mostly using <a class="reference external" href="http://llvm.org/docs/TableGenFundamentals.html">TableGen</a>, so you need to be
|
|
familiar with it to get anything done.</p>
|
|
<p>Start by compiling <tt class="docutils literal">example/Simple</tt>, which is a primitive wrapper for
|
|
<tt class="docutils literal">gcc</tt>:</p>
|
|
<pre class="literal-block">
|
|
$ cd $LLVM_OBJ_DIR/tools/examples/Simple
|
|
$ make
|
|
$ cat > hello.c
|
|
#include <stdio.h>
|
|
int main() { printf("Hello\n"); }
|
|
$ $LLVM_BIN_DIR/Simple -v hello.c
|
|
gcc hello.c -o hello.out
|
|
$ ./hello.out
|
|
Hello
|
|
</pre>
|
|
<p>We have thus produced a simple driver called, appropriately, <tt class="docutils literal">Simple</tt>, from
|
|
the input TableGen file <tt class="docutils literal">Simple.td</tt>. The <tt class="docutils literal">llvmc</tt> program itself is generated
|
|
using a similar process (see <tt class="docutils literal">llvmc/src</tt>). Contents of the file <tt class="docutils literal">Simple.td</tt>
|
|
look like this:</p>
|
|
<pre class="literal-block">
|
|
// Include common definitions
|
|
include "llvm/CompilerDriver/Common.td"
|
|
|
|
// Tool descriptions
|
|
def gcc : Tool<
|
|
[(in_language "c"),
|
|
(out_language "executable"),
|
|
(output_suffix "out"),
|
|
(command "gcc"),
|
|
(sink),
|
|
|
|
// -o is what is used by default, out_file_option here is included for
|
|
// instructive purposes.
|
|
(out_file_option "-o")
|
|
]>;
|
|
|
|
// Language map
|
|
def LanguageMap : LanguageMap<[(lang_to_suffixes "c", "c")]>;
|
|
|
|
// Compilation graph
|
|
def CompilationGraph : CompilationGraph<[(edge "root", "gcc")]>;
|
|
</pre>
|
|
<p>As you can see, this file consists of three parts: tool descriptions, language
|
|
map, and the compilation graph definition.</p>
|
|
<p>At the heart of LLVMC is the idea of a compilation graph: vertices in this graph
|
|
are tools, and edges represent a transformation path between two tools (for
|
|
example, assembly source produced by the compiler can be transformed into
|
|
executable code by an assembler). The compilation graph is basically a list of
|
|
edges; a special node named <tt class="docutils literal">root</tt> is used to mark graph entry points.</p>
|
|
<p>Tool descriptions are represented as property lists: most properties in the
|
|
example above should be self-explanatory; the <tt class="docutils literal">sink</tt> property means that all
|
|
options lacking an explicit description should be forwarded to this tool.</p>
|
|
<p>The <tt class="docutils literal">LanguageMap</tt> associates a language name with a list of suffixes and is
|
|
used for deciding which toolchain corresponds to a given input file.</p>
|
|
<p>To learn more about writing your own drivers with LLVMC, refer to the reference
|
|
manual and examples in the <tt class="docutils literal">examples</tt> directory. Of a particular interest is
|
|
the <tt class="docutils literal">Skeleton</tt> example, which can serve as a template for your LLVMC-based
|
|
drivers.</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>
|
|
</body>
|
|
</html>
|