mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-07-19 03:29:22 +00:00
44ac659bc5
* Convert directories to <tt> like they should be git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3270 91177308-0d34-0410-b5e6-96231b3b80d8
370 lines
16 KiB
HTML
370 lines
16 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<html>
|
|
<head>
|
|
<title>Getting Started with LLVM System</title>
|
|
</head>
|
|
|
|
<body bgcolor=white>
|
|
<h1>Getting Started with the LLVM System<br><font size=3>By: <a
|
|
href="mailto:gshi1@uiuc.edu">Guochun Shi</a> and <a
|
|
href="mailto:sabre@nondot.org">Chris Lattner</a></font></h1>
|
|
|
|
<ul>
|
|
<li><a href="#quickstart">Getting started with LLVM</a>
|
|
<ol>
|
|
<li><a href="#cvs">Checkout LLVM from CVS</a>
|
|
<li><a href="#environment">Set up your environment</a>
|
|
<li><a href="#compile">Compiling the Source Code</a>
|
|
</ol>
|
|
<li><a href="#layout">Program layout</a>
|
|
<ol>
|
|
<li><a href="#cvsdir">CVS directories</a>
|
|
<li><a href="#dd"><tt>Depend</tt>, <tt>Debug</tt>, &
|
|
<tt>Release</tt> directories</a></li>
|
|
<li><a href="#include"><tt>llvm/include</tt></a>
|
|
<li><a href="#lib"><tt>llvm/lib</tt></a>
|
|
<li><a href="#test"><tt>llvm/test</tt></a>
|
|
<li><a href="#tools"><tt>llvm/tools</tt></a>
|
|
</ol>
|
|
<li><a href="#tutorial">An example using the LLVM tool chain</a>
|
|
<li><a href="#links">Links</a>
|
|
</ul>
|
|
|
|
|
|
|
|
<!--=====================================================================-->
|
|
<h2><a name="quickstart">Getting Started with LLVM</a></h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p>This guide is meant to get you up and running with LLVM as quickly as
|
|
possible. Once you get the basic system running you can choose an area to
|
|
dive into and learn more about. If you get stuck or something is missing
|
|
from this document, please email <a
|
|
href="mailto:sabre@nondot.org">Chris</a>.</p>
|
|
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="tools">Checkout LLVM from CVS</a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
<p>First step is to get the actual source code. To do this, all you need to
|
|
do is check it out from CVS. From your home directory, just enter:</p>
|
|
|
|
<p><tt>cvs -d /home/vadve/vadve/Research/DynOpt/CVSRepository checkout
|
|
llvm</tt></p>
|
|
|
|
<p>This will create an '<tt>llvm</tt>' directory in your home directory and
|
|
fully populate it with the source code for LLVM.</p>
|
|
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="tools">Set up your environment</a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
<p>Now that you have the source code available, you should set up your
|
|
environment to be able to use the LLVM tools (once compiled) with as little
|
|
hassle as possible. To do this, we recommend that you add the following
|
|
lines to your <tt>.cshrc</tt> (or the corresponding lines to your
|
|
<tt>.profile</tt> if you use a bourne shell derivative):
|
|
|
|
<pre>
|
|
# Make the C frontend easy to use...
|
|
alias llvmgcc /home/vadve/lattner/cvs/gcc_install/bin/gcc
|
|
|
|
# Make the LLVM tools easy to use...
|
|
setenv PATH ~/llvm/tools/Debug:${PATH}
|
|
</pre>
|
|
|
|
<p>The C compiler is not included in the CVS tree you just checked out, so
|
|
we just point to the cannonical location, and access it with the
|
|
<tt>llvmgcc</tt> command. The rest of the <a href="#tools">LLVM tools</a>
|
|
will be built into the <tt>llvm/tools/Debug</tt> directory inside of the
|
|
sourcebase. Adding them to your path will make it much easier to use
|
|
them.</p>
|
|
|
|
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="compile">Compiling the Source Code</a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
<p>Every directory in the LLVM source tree includes a Makefile to build it,
|
|
and any subdirectories that it contains. These makefiles require that you
|
|
use <tt>gmake</tt>, instead of <tt>make</tt> to build them, but can
|
|
otherwise be used freely. To build the entire LLVM system, just enter the
|
|
top level <tt>llvm</tt> directory and type <tt>gmake</tt>. A few minutes
|
|
later you will hopefully have a freshly compiled toolchain waiting for you
|
|
in <tt>llvm/tools/Debug</tt>. If you want to look at the libraries that
|
|
were compiled, look in <tt>llvm/lib/Debug</tt>.</p>
|
|
|
|
<p>By default, the LLVM build process sends all temporary (<tt>.o</tt>,
|
|
<tt>.so</tt>, <tt>.a</tt>) files into a <tt>/shared/[your login
|
|
name]/...</tt> directory, which is supposed to be on a disk local to the
|
|
current machine. If you get an error talking about a <tt>/shared</tt>
|
|
directory, and you find out that it doesn't exist, try enabling the
|
|
"<tt>BUILD_ROOT = .</tt> line in the top level <tt>Makefile.common</tt> that
|
|
will change LLVM to build into the current directory instead of
|
|
<tt>/shared</tt>.<p>
|
|
|
|
|
|
<!--=====================================================================-->
|
|
<h2><a name="layout">Program Layout</a></h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p>One useful source of infomation about the LLVM sourcebase is the LLVM <a
|
|
href="http://www.doxygen.org">doxygen</a> documentation, available at <tt><a
|
|
href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>. The
|
|
following is a brief introduction to code layout:</p>
|
|
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="cvsdir"><tt>CVS</tt> directories</a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
Every directory checked out of CVS will contain a <tt>CVS</tt> directory,
|
|
for the most part these can just be ignored.
|
|
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="ddr"><tt>Depend</tt>, <tt>Debug</tt>, & <tt>Release</tt>
|
|
directories</a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
If you are building with the "<tt>BUILD_ROOT=.</tt>" option enabled in the
|
|
<tt>Makefile.common</tt> file, most source directories will contain two
|
|
directories, <tt>Depend</tt> and <tt>Debug</tt>. The <tt>Depend</tt>
|
|
directory contains automatically generated dependance files which are used
|
|
during compilation to make sure that source files get rebuilt if a header
|
|
file they use is modified. The <tt>Debug</tt> directory holds the object
|
|
files, library files and executables that are used for building a debug
|
|
enabled build. The <tt>Release</tt> directory is created to hold the same
|
|
files when the <tt>ENABLE_OPTIMIZED=1</tt> flag is passed to <tt>gmake</tt>,
|
|
causing an optimized built to be performed.<p>
|
|
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="include"><tt>llvm/include</tt></a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
This directory contains public header files exported from the LLVM
|
|
library. The two main subdirectories of this directory are:<p>
|
|
|
|
<ol>
|
|
<li><tt>llvm/include/llvm</tt> - This directory contains all of the LLVM
|
|
specific header files. This directory also has subdirectories for
|
|
different portions of llvm: <tt>Analysis</tt>, <tt>CodeGen</tt>,
|
|
<tt>Reoptimizer</tt>, <tt>Target</tt>, <tt>Transforms</tt>, etc...
|
|
|
|
<li><tt>llvm/include/Support</tt> - This directory contains generic
|
|
support libraries that are independant of LLVM, but are used by LLVM.
|
|
For example, some C++ STL utilities and a Command Line option processing
|
|
library.
|
|
</ol>
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="lib"><tt>llvm/lib</tt></a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
This directory contains most source files of LLVM system. In LLVM almost all
|
|
code exists in libraries, making it very easy to share code among the
|
|
different <a href="#tools">tools</a>.<p>
|
|
|
|
<dl compact>
|
|
<dt><tt>llvm/lib/VMCore/</tt><dd> This directory holds the core LLVM
|
|
source files that implement core classes like Instruction and BasicBlock.
|
|
|
|
<dt><tt>llvm/lib/AsmParser/</tt><dd> This directory holds the source code
|
|
for the LLVM assembly language parser library.
|
|
|
|
<dt><tt>llvm/lib/ByteCode/</tt><dd> This directory holds code for reading
|
|
and write LLVM bytecode.
|
|
|
|
<dt><tt>llvm/lib/CWrite/</tt><dd> This directory implements the LLVM to C
|
|
converter.
|
|
|
|
<dt><tt>llvm/lib/Analysis/</tt><dd> This directory contains a variety of
|
|
different program analyses, such as Dominator Information, Call Graphs,
|
|
Induction Variables, Interval Identification, Natural Loop Identification,
|
|
etc...
|
|
|
|
<dt><tt>llvm/lib/Transforms/</tt><dd> This directory contains the source
|
|
code for the LLVM to LLVM program transformations, such as Aggressive Dead
|
|
Code Elimination, Sparse Conditional Constant Propogation, Inlining, Loop
|
|
Invarient Code Motion, Dead Global Elimination, Pool Allocation, and many
|
|
others...
|
|
|
|
<dt><tt>llvm/lib/Target/</tt><dd> This directory contains files that
|
|
describe various target architectures for code generation. For example,
|
|
the llvm/lib/Target/Sparc directory holds the Sparc machine
|
|
description.<br>
|
|
|
|
<dt><tt>llvm/lib/CodeGen/</tt><dd> This directory contains the major parts
|
|
of the code generator: Instruction Selector, Instruction Scheduling, and
|
|
Register Allocation.
|
|
|
|
<dt><tt>llvm/lib/Reoptimizer/</tt><dd> This directory holds code related
|
|
to the runtime reoptimizer framework that is currently under development.
|
|
|
|
<dt><tt>llvm/lib/Support/</tt><dd> This directory contains the source code
|
|
that corresponds to the header files located in
|
|
<tt>llvm/include/Support/</tt>.
|
|
</dl>
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="test"><tt>llvm/test</tt></a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
<p>This directory contains regression tests and source code that is used to
|
|
test the LLVM infrastructure...</p>
|
|
|
|
<!------------------------------------------------------------------------->
|
|
<h3><a name="tools"><tt>llvm/tools</tt></a></h3>
|
|
<!------------------------------------------------------------------------->
|
|
|
|
<p>The <b>tools</b> directory contains the executables built out of the
|
|
libraries above, which form the main part of the user interface. You can
|
|
always get help for a tool by typing <tt>tool_name --help</tt>. The
|
|
following is a brief introduction to the most important tools.</p>
|
|
|
|
<dl compact>
|
|
<dt><tt><b>as</b></tt><dd>The assembler transforms the human readable
|
|
llvm assembly to llvm bytecode.<p>
|
|
|
|
<dt><tt><b>dis</b></tt><dd>The disassembler transforms the llvm bytecode
|
|
to human readable llvm assembly. Additionally it can convert LLVM
|
|
bytecode to C, which is enabled with the <tt>-c</tt> option.<p>
|
|
|
|
<dt><tt><b>lli</b></tt><dd> <tt>lli</tt> is the LLVM interpreter, which
|
|
can directly execute LLVM bytecode (although very slowly...). In addition
|
|
to a simple intepreter, <tt>lli</tt> is also has debugger and tracing
|
|
modes (entered by specifying <tt>-debug</tt> or <tt>-trace</tt> on the
|
|
command line, respectively).<p>
|
|
|
|
<dt><tt><b>llc</b></tt><dd> <tt>llc</tt> is the LLVM backend compiler,
|
|
which translates LLVM bytecode to a SPARC assembly file.<p>
|
|
|
|
<dt><tt><b>llvmgcc</b></tt><dd> <tt>llvmgcc</tt> is a GCC based C frontend
|
|
that has been retargeted to emit LLVM code as the machine code output. It
|
|
works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
|
|
-o</tt> options that are typically used. The source code for the
|
|
<tt>llvmgcc</tt> tool is currently not included in the LLVM cvs tree
|
|
because it is quite large and not very interesting.<p>
|
|
|
|
<ol>
|
|
<dt><tt><b>gccas</b></tt><dd> This took is invoked by the
|
|
<tt>llvmgcc</tt> frontend as the "assembler" part of the compiler. This
|
|
tool actually assembles its input, performs a variety of optimizations,
|
|
and outputs LLVM bytecode. Thus when you invoke <tt>llvmgcc -c x.c -o
|
|
x.o</tt>, you are causing <tt>gccas</tt> to be run, which writes the
|
|
<tt>x.o</tt> file (which is an LLVM bytecode file that can be
|
|
disassembled or manipulated just like any other bytecode file). The
|
|
command line interface to <tt>gccas</tt> is designed to be as close as
|
|
possible to the <b>system</b> <tt>as</tt> utility so that the gcc
|
|
frontend itself did not have to be modified to interface to a "wierd"
|
|
assembler.<p>
|
|
|
|
<dt><tt><b>gccld</b></tt><dd> <tt>gccld</tt> links together several llvm
|
|
bytecode files into one bytecode file and does some optimization. It is
|
|
the linker invoked by the gcc frontend when multiple .o files need to be
|
|
linked together. Like <tt>gccas</tt> the command line interface of
|
|
<tt>gccld</tt> is designed to match the system linker, to aid
|
|
interfacing with the GCC frontend.<p>
|
|
</ol>
|
|
|
|
<dt><tt><b>opt</b></tt><dd> <tt>opt</tt> reads llvm bytecode, applies a
|
|
series of LLVM to LLVM transformations (which are specified on the command
|
|
line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
|
|
command is a good way to get a list of the program transformations
|
|
available in LLVM.<p>
|
|
|
|
|
|
<dt><tt><b>analyze</b></tt><dd> <tt>analyze</tt> is used to run a specific
|
|
analysis on an input LLVM bytecode file and print out the results. It is
|
|
primarily useful for debugging analyses, or familiarizing yourself with
|
|
what an analysis does.<p>
|
|
|
|
</dl>
|
|
|
|
<!--=====================================================================-->
|
|
<h2><a name="tutorial">An example using the LLVM tool chain</h2>
|
|
<!--=====================================================================-->
|
|
|
|
<ol>
|
|
<li>First, create a simple C file, name it 'hello.c':
|
|
<pre>
|
|
#include <stdio.h>
|
|
int main() {
|
|
printf("hello world\n");
|
|
return 0;
|
|
}
|
|
</pre>
|
|
|
|
<li>Next, compile the C file into a LLVM bytecode file:<p>
|
|
|
|
<tt>% llvmgcc hello.c -o hello</tt><p>
|
|
|
|
This will create two result files: <tt>hello</tt> and
|
|
<tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
|
|
corresponds the the compiled program and the library facilities that it
|
|
required. <tt>hello</tt> is a simple shell script that runs the bytecode
|
|
file with <tt>lli</tt>, making the result directly executable.<p>
|
|
|
|
<li>Run the program. To make sure the program ran, execute one of the
|
|
following commands:<p>
|
|
|
|
<tt>% ./hello</tt><p>
|
|
|
|
or<p>
|
|
|
|
<tt>% lli hello.bc</tt><p>
|
|
|
|
<li>Use the <tt>dis</tt> utility to take a look at the LLVM assembly
|
|
code:<p>
|
|
|
|
<tt>% dis < hello.bc | less</tt><p>
|
|
|
|
<li>Compile the program to native Sparc assembly using the code
|
|
generator:<p>
|
|
|
|
<tt>% llc hello.bc -o hello.s</tt><p>
|
|
|
|
<li>Assemble the native sparc assemble file into a program:<p>
|
|
|
|
<tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc</tt><p>
|
|
|
|
<li>Execute the native sparc program:<p>
|
|
|
|
<tt>% ./hello.sparc</tt><p>
|
|
|
|
</ol>
|
|
|
|
|
|
<!--=====================================================================-->
|
|
<h2><a name="links">Links</a></h2>
|
|
<!--=====================================================================-->
|
|
|
|
<p>This document is just an <b>introduction</b> to how to use LLVM to do
|
|
some simple things... there are many more interesting and complicated things
|
|
that you can do that aren't documented here (but we'll gladly accept a patch
|
|
if you want to write something up!). For more information about LLVM, check
|
|
out:</p>
|
|
|
|
<ul>
|
|
<li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
|
|
<li><a href="http://tank.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
|
|
</ul>
|
|
|
|
<hr>
|
|
|
|
If you have any questions or run into any snags (or you have any
|
|
additions...), please send an email to <a
|
|
href="mailto:sabre@nondot.org">Chris Lattner</a> or <a
|
|
href="mailto:gshi1@uiuc.edu">Guochun Shi</a>. <p>
|
|
|
|
<!-- Created: Mon Jul 1 02:29:02 CDT 2002 -->
|
|
<!-- hhmts start -->
|
|
Last modified: Fri Aug 9 11:13:34 CDT 2002
|
|
<!-- hhmts end -->
|
|
</body>
|
|
</html>
|