mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-15 04:30:12 +00:00
4aecec1f50
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73596 91177308-0d34-0410-b5e6-96231b3b80d8
130 lines
4.2 KiB
ReStructuredText
130 lines
4.2 KiB
ReStructuredText
======================
|
|
Tutorial - Using LLVMC
|
|
======================
|
|
..
|
|
This file was automatically generated by rst2html.
|
|
Please do not edit directly!
|
|
The ReST source lives in the directory 'tools/llvmc/doc'.
|
|
|
|
.. contents::
|
|
|
|
.. raw:: html
|
|
|
|
<div class="doc_author">
|
|
<p>Written by <a href="mailto:foldr@codedgers.com">Mikhail Glushenkov</a></p>
|
|
</div>
|
|
|
|
Introduction
|
|
============
|
|
|
|
LLVMC is a generic compiler driver, which plays the same role for LLVM
|
|
as the ``gcc`` 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 plugins, which can be loaded
|
|
dynamically or compiled in. This tutorial describes the basic usage
|
|
and configuration of LLVMC.
|
|
|
|
|
|
Compiling with LLVMC
|
|
====================
|
|
|
|
In general, LLVMC tries to be command-line compatible with ``gcc`` as
|
|
much as possible, so most of the familiar options work::
|
|
|
|
$ llvmc -O3 -Wall hello.cpp
|
|
$ ./a.out
|
|
hello
|
|
|
|
This will invoke ``llvm-g++`` under the hood (you can see which
|
|
commands are executed by using the ``-v`` option). For further help on
|
|
command-line LLVMC usage, refer to the ``llvmc --help`` output.
|
|
|
|
|
|
Using LLVMC to generate toolchain drivers
|
|
=========================================
|
|
|
|
LLVMC plugins are written mostly using TableGen_, so you need to
|
|
be familiar with it to get anything done.
|
|
|
|
.. _TableGen: http://llvm.org/docs/TableGenFundamentals.html
|
|
|
|
Start by compiling ``example/Simple``, which is a primitive wrapper for
|
|
``gcc``::
|
|
|
|
$ cd $LLVM_DIR/tools/llvmc
|
|
$ cp -r example/Simple plugins/Simple
|
|
|
|
# NB: A less verbose way to compile standalone LLVMC-based drivers is
|
|
# described in the reference manual.
|
|
|
|
$ make LLVMC_BASED_DRIVER_NAME=mygcc LLVMC_BUILTIN_PLUGINS=Simple
|
|
$ cat > hello.c
|
|
[...]
|
|
$ mygcc hello.c
|
|
$ ./hello.out
|
|
Hello
|
|
|
|
Here we link our plugin with the LLVMC core statically to form an executable
|
|
file called ``mygcc``. It is also possible to build our plugin as a dynamic
|
|
library to be loaded by the ``llvmc`` executable (or any other LLVMC-based
|
|
standalone driver); this is described in the reference manual.
|
|
|
|
Contents of the file ``Simple.td`` look like this::
|
|
|
|
// Include common definitions
|
|
include "llvm/CompilerDriver/Common.td"
|
|
|
|
// Tool descriptions
|
|
def gcc : Tool<
|
|
[(in_language "c"),
|
|
(out_language "executable"),
|
|
(output_suffix "out"),
|
|
(cmd_line "gcc $INFILE -o $OUTFILE"),
|
|
(sink)
|
|
]>;
|
|
|
|
// Language map
|
|
def LanguageMap : LanguageMap<[LangToSuffixes<"c", ["c"]>]>;
|
|
|
|
// Compilation graph
|
|
def CompilationGraph : CompilationGraph<[Edge<"root", "gcc">]>;
|
|
|
|
As you can see, this file consists of three parts: tool descriptions,
|
|
language map, and the compilation graph definition.
|
|
|
|
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
|
|
``root`` is used to mark graph entry points.
|
|
|
|
Tool descriptions are represented as property lists: most properties
|
|
in the example above should be self-explanatory; the ``sink`` property
|
|
means that all options lacking an explicit description should be
|
|
forwarded to this tool.
|
|
|
|
The ``LanguageMap`` associates a language name with a list of suffixes
|
|
and is used for deciding which toolchain corresponds to a given input
|
|
file.
|
|
|
|
To learn more about LLVMC customization, refer to the reference
|
|
manual and plugin source code in the ``plugins`` directory.
|
|
|
|
.. raw:: html
|
|
|
|
<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>
|