Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 1db872dd1000d6edb03a79344ea3c4c6b58872d7 / . / docs / GettingStarted.html
blob: 9c16d65f91cbe43f9777910476e94965e2ec1453 [file] [log] [blame]
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2<html>
3 <head>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]4 <title>Getting Started with LLVM System</title>
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]5 </head>
6
Chris Lattner945de2d2002-07-24 19:59:33 +0000[diff] [blame]7 <body bgcolor=white>
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]8 <center><h1>Getting Started with the LLVM System<br><font size=3>By: <a
9 href="mailto:gshi1@uiuc.edu">Guochun Shi</a>,
10 <a href="mailto:sabre@nondot.org">Chris Lattner</a> and
11 <a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>
12 </font></h1></center>
13
14 <!--=====================================================================-->
15 <h2><a name="Contents">Contents</a></h2>
16 <!--=====================================================================-->
Chris Lattner945de2d2002-07-24 19:59:33 +0000[diff] [blame]17
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]18 <ul>
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]19 <li><a href="#overview">Overview</a>
20 <li><a href="#starting">Getting started with LLVM</a>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]21 <ol>
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]22 <li><a href="#quickstart">Getting started quickly (a summary)</a>
23 <li><a href="#checkout">Checkout LLVM from CVS</a>
24 <li><a href="#terminology">Terminology and Notation</tt></a>
25 <li><a href="#objfiles">The location for object files</tt></a>
26 <li><a href="#config">Local Configuration Options</tt></a>
27 <li><a href="#environment">Setting up your environment</a>
28 <li><a href="#compile">Compiling the source code</a>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]29 </ol>
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]30 <li><a href="#layout">Program layout</a>
31 <ol>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]32 <li><a href="#cvsdir">CVS directories</a>
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]33 <li><a href="#dd"><tt>Depend</tt>, <tt>Debug</tt>, &amp;
34 <tt>Release</tt> directories</a></li>
35 <li><a href="#include"><tt>llvm/include</tt></a>
36 <li><a href="#lib"><tt>llvm/lib</tt></a>
37 <li><a href="#test"><tt>llvm/test</tt></a>
38 <li><a href="#tools"><tt>llvm/tools</tt></a>
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]39 </ol>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]40 <li><a href="#tutorial">An example using the LLVM tool chain</a>
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]41 <li><a href="#links">Links</a>
42 </ul>
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]43
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]44
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]45 <!--=====================================================================-->
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]46 <center>
47 <h2><a name="overview"><b>Overview</b></a></h2>
48 </center>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]49 <!--=====================================================================-->
50
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]51 <p>The <a href"starting">next section</a> of this guide is meant to get
52 you up and running with LLVM, and to give you some basic information about
53 the LLVM environment. The <a href"#quickstart">first subsection</a> gives
54 a short summary for those who are already familiar with the system and
55 want to get started as quickly as possible.
56
57 <p>The later sections of this guide describe the <a
58 href"#layout">general layout</a> of the the llvm source tree, a <a
59 href="#tutorial">simple example</a> using the LLVM tool chain, and <a
60 href="#links">links</a> to find more information about LLVM or to get
61 help via e-mail.
62
63 <!--=====================================================================-->
64 <center>
65 <h2><a name="starting"><b>Getting Started</b></a></h2>
66 </center>
67 <!--=====================================================================-->
68
69
70 <!--=====================================================================-->
71 <h3><a name="quickstart"><b>Getting Started Quickly (A Summary)</b></a></h3>
72 <!--=====================================================================-->
73
74 Here's the short story for getting up and running quickly with LLVM:
75 <ul>
76 <li>Find the path to the CVS repository containing LLVM (we'll call this <i>CVSROOTDIR</i>).
77 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
78 <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt>
79 <li>Edit <tt>llvm/Makefile.config</tt> to set local paths if necessary.
80 <li><tt>cd llvm</tt>
81 <li><tt>gmake -k |& tee gnumake.out
82 &nbsp;&nbsp;&nbsp;# this is csh or tcsh syntax</tt>
83 </ul>
84
85 <p>See <a href="#environment">Setting up your environment</a> on tips to
86 simplify working with the llvm front-end and compiled tools. See the
87 other sub-sections below for other useful details in working with LLVM,
88 or go straight to <a href="#layout">Program Layout</a> to learn about the
89 layout of the source code tree.
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]90
91 <!------------------------------------------------------------------------->
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]92 <h3><a name="terminology">Terminology and Notation</a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]93 <!------------------------------------------------------------------------->
94
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]95 <p>Through this manual, the following names are used to denote paths
96 specific to the local system and working environment. <i>These are not
97 environment variables you need to set, but just strings used in the rest
98 of this document below.</i>. In any of the examples below, simply replace
99 each of these names with the appropriate pathname on your local system.
100 All these paths are absolute:</p>
101 <ul>
102 </ul>
Chris Lattnercefbd322002-08-13 21:10:30 +0000[diff] [blame]103
104 <!------------------------------------------------------------------------->
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]105 <h3><a name="checkout">Checkout LLVM from CVS</a></h3>
Chris Lattnercefbd322002-08-13 21:10:30 +0000[diff] [blame]106 <!------------------------------------------------------------------------->
107
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]108 <p>Before checking out the source code, you will need to know the path to
109 CVS repository containing LLVM source code (we'll call this
110 <i>CVSROOTDIR</i> below). Ask the person responsible for your local LLVM
111 installation to give you this path.
Chris Lattnercefbd322002-08-13 21:10:30 +0000[diff] [blame]112
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]113 <p>To get a fresh copy of the entire source code, all you
114 need to do is check it out from CVS as follows:
115 <ul>
116 <li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
117 <li><tt>cvs -d <i>CVSROOTDIR</i> checkout llvm</tt></p>
118 </ul>
119
120 <p>This will create an '<tt>llvm</tt>' directory in the current
121 directory and fully populate it with the LLVM source code, Makefiles,
122 test directories, and local copies of documentation files.</p>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]123
124 <!------------------------------------------------------------------------->
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]125 <h3><a name="config">Local Configuration Options</a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]126 <!------------------------------------------------------------------------->
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]127
128 <p>The file <tt>llvm/Makefile.config</tt>
129 defines the following path variables,
130 which are specific to a particular installation of LLVM.
131 These should need to be modified only once after checking out a copy
132 of LLVM (if the default values do not already match your system):
133
134 <ul>
135 <p><li><i>LLVM_OBJ_DIR</i> = Path to the llvm directory where
136 object files should be placed.
137 (See the Section on <a href=#objfiles>
138 The location for LLVM object files</a>
139 for more information.)
140 <p><li><i>LLVMGCCDIR</i> = Path to the location of the LLVM front-end
141 binaries and associated libraries.
142 <p><li><i>BURG</i> = Path to the burg program used for instruction
143 selection.
144 <p><li><i>PURIFY</i> = Path to the purify program.
145 </ul>
146
147 <!------------------------------------------------------------------------->
148 <h3><a name="objfiles">The location for LLVM object files</a></h3>
149 <!------------------------------------------------------------------------->
150
151 <p>The LLVM make system sends most output files generated during the build
152 into the directory defined by the variable LLVM_OBJ_DIR in
153 <tt>llvm/Makefile.config</tt>.
154 This can be either just your normal </tt>llvm</tt> source tree or some
155 other directory writable by you. You may wish to put object files on a
156 different filesystem either to keep them from being backed up or to speed
157 up local builds.
158
159 <p>If you do not wish to use a different location for object files,
160 just set this variable to ".".
161
162 <!------------------------------------------------------------------------->
163 <h3><a name="environment">Setting up your environment</a></h3>
164 <!------------------------------------------------------------------------->
165
166 <i>NOTE: This step is optional but will set up your environment so you
167 can use the compiled LLVM tools with as little hassle as possible.</i>)
168
169 <p>Add the following lines to your <tt>.cshrc</tt> (or the corresponding
170 lines to your <tt>.profile</tt> if you use a bourne shell derivative).
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]171
172 <pre>
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]173 # Make the C front end easy to use...
174 alias llvmgcc <i>LLVMGCCDIR</i><tt>/bin/gcc</tt>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]175
176 # Make the LLVM tools easy to use...
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]177 setenv PATH <i>LLVM_OBJ_DIR</i>/tools/Debug:${PATH}
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]178 </pre>
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]179 The <tt>llvmgcc</tt> alias is useful because the C compiler is not
180 included in the CVS tree you just checked out.
181
182 <p>The other LLVM <a href="#tools">LLVM tools</a> are part of the LLVM
183 source base, and built when compiling LLVM. They will be built into the
184 <tt><i>LLVM_OBJ_DIR</i>/tools/Debug</tt> directory.</p>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]185
186 <!------------------------------------------------------------------------->
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]187 <h3><a name="compile">Compiling the source code</a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]188 <!------------------------------------------------------------------------->
189
190 <p>Every directory in the LLVM source tree includes a Makefile to build it,
191 and any subdirectories that it contains. These makefiles require that you
192 use <tt>gmake</tt>, instead of <tt>make</tt> to build them, but can
193 otherwise be used freely. To build the entire LLVM system, just enter the
194 top level <tt>llvm</tt> directory and type <tt>gmake</tt>. A few minutes
195 later you will hopefully have a freshly compiled toolchain waiting for you
196 in <tt>llvm/tools/Debug</tt>. If you want to look at the libraries that
197 were compiled, look in <tt>llvm/lib/Debug</tt>.</p>
198
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]199 If you get an error talking about a <tt>/shared</tt> directory, follow the
200 instructions in the section about <a href="#environment">Setting Up Your
201 Environment.</a>
Chris Lattnercefbd322002-08-13 21:10:30 +0000[diff] [blame]202
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]203
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]204
205 <!--=====================================================================-->
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]206 <center>
207 <h2><a name="layout"><b>Program Layout</b></a></h2>
208 </center>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]209 <!--=====================================================================-->
210
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]211 <p>One useful source of infomation about the LLVM sourcebase is the LLVM <a
212 href="http://www.doxygen.org">doxygen</a> documentation, available at <tt><a
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]213 href="http://llvm.cs.uiuc.edu/doxygen/">http://llvm.cs.uiuc.edu/doxygen/</a></tt>. The
214 following is a brief introduction to code layout:</p>
215
216
217 <!------------------------------------------------------------------------->
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]218 <h3><a name="cvsdir"><tt>CVS</tt> directories</a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]219 <!------------------------------------------------------------------------->
220
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]221 Every directory checked out of CVS will contain a <tt>CVS</tt> directory,
222 for the most part these can just be ignored.
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]223
224
225 <!------------------------------------------------------------------------->
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]226 <h3><a name="ddr"><tt>Depend</tt>, <tt>Debug</tt>, &amp; <tt>Release</tt>
227 directories</a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]228 <!------------------------------------------------------------------------->
229
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]230 If you are building with the "<tt>BUILD_ROOT=.</tt>" option enabled in the
231 <tt>Makefile.common</tt> file, most source directories will contain two
232 directories, <tt>Depend</tt> and <tt>Debug</tt>. The <tt>Depend</tt>
233 directory contains automatically generated dependance files which are used
234 during compilation to make sure that source files get rebuilt if a header
235 file they use is modified. The <tt>Debug</tt> directory holds the object
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]236 files, library files and executables that are used for building a debug
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]237 enabled build. The <tt>Release</tt> directory is created to hold the same
238 files when the <tt>ENABLE_OPTIMIZED=1</tt> flag is passed to <tt>gmake</tt>,
239 causing an optimized built to be performed.<p>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]240
241
242 <!------------------------------------------------------------------------->
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]243 <h3><a name="include"><tt>llvm/include</tt></a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]244 <!------------------------------------------------------------------------->
245
246 This directory contains public header files exported from the LLVM
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]247 library. The two main subdirectories of this directory are:<p>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]248
249 <ol>
250 <li><tt>llvm/include/llvm</tt> - This directory contains all of the LLVM
251 specific header files. This directory also has subdirectories for
252 different portions of llvm: <tt>Analysis</tt>, <tt>CodeGen</tt>,
253 <tt>Reoptimizer</tt>, <tt>Target</tt>, <tt>Transforms</tt>, etc...
254
255 <li><tt>llvm/include/Support</tt> - This directory contains generic
256 support libraries that are independant of LLVM, but are used by LLVM.
257 For example, some C++ STL utilities and a Command Line option processing
258 library.
259 </ol>
260
261 <!------------------------------------------------------------------------->
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]262 <h3><a name="lib"><tt>llvm/lib</tt></a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]263 <!------------------------------------------------------------------------->
264
265 This directory contains most source files of LLVM system. In LLVM almost all
266 code exists in libraries, making it very easy to share code among the
267 different <a href="#tools">tools</a>.<p>
268
269 <dl compact>
270 <dt><tt>llvm/lib/VMCore/</tt><dd> This directory holds the core LLVM
271 source files that implement core classes like Instruction and BasicBlock.
272
273 <dt><tt>llvm/lib/AsmParser/</tt><dd> This directory holds the source code
274 for the LLVM assembly language parser library.
275
276 <dt><tt>llvm/lib/ByteCode/</tt><dd> This directory holds code for reading
277 and write LLVM bytecode.
278
279 <dt><tt>llvm/lib/CWrite/</tt><dd> This directory implements the LLVM to C
280 converter.
281
282 <dt><tt>llvm/lib/Analysis/</tt><dd> This directory contains a variety of
283 different program analyses, such as Dominator Information, Call Graphs,
284 Induction Variables, Interval Identification, Natural Loop Identification,
285 etc...
286
287 <dt><tt>llvm/lib/Transforms/</tt><dd> This directory contains the source
288 code for the LLVM to LLVM program transformations, such as Aggressive Dead
289 Code Elimination, Sparse Conditional Constant Propogation, Inlining, Loop
290 Invarient Code Motion, Dead Global Elimination, Pool Allocation, and many
291 others...
292
293 <dt><tt>llvm/lib/Target/</tt><dd> This directory contains files that
294 describe various target architectures for code generation. For example,
295 the llvm/lib/Target/Sparc directory holds the Sparc machine
296 description.<br>
297
298 <dt><tt>llvm/lib/CodeGen/</tt><dd> This directory contains the major parts
299 of the code generator: Instruction Selector, Instruction Scheduling, and
300 Register Allocation.
301
302 <dt><tt>llvm/lib/Reoptimizer/</tt><dd> This directory holds code related
303 to the runtime reoptimizer framework that is currently under development.
304
305 <dt><tt>llvm/lib/Support/</tt><dd> This directory contains the source code
306 that corresponds to the header files located in
307 <tt>llvm/include/Support/</tt>.
308 </dl>
309
310 <!------------------------------------------------------------------------->
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]311 <h3><a name="test"><tt>llvm/test</tt></a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]312 <!------------------------------------------------------------------------->
313
314 <p>This directory contains regression tests and source code that is used to
315 test the LLVM infrastructure...</p>
316
317 <!------------------------------------------------------------------------->
Chris Lattner44ac6592002-08-09 16:14:56 +0000[diff] [blame]318 <h3><a name="tools"><tt>llvm/tools</tt></a></h3>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]319 <!------------------------------------------------------------------------->
320
321 <p>The <b>tools</b> directory contains the executables built out of the
322 libraries above, which form the main part of the user interface. You can
323 always get help for a tool by typing <tt>tool_name --help</tt>. The
324 following is a brief introduction to the most important tools.</p>
325
326 <dl compact>
327 <dt><tt><b>as</b></tt><dd>The assembler transforms the human readable
328 llvm assembly to llvm bytecode.<p>
329
330 <dt><tt><b>dis</b></tt><dd>The disassembler transforms the llvm bytecode
331 to human readable llvm assembly. Additionally it can convert LLVM
332 bytecode to C, which is enabled with the <tt>-c</tt> option.<p>
333
334 <dt><tt><b>lli</b></tt><dd> <tt>lli</tt> is the LLVM interpreter, which
335 can directly execute LLVM bytecode (although very slowly...). In addition
336 to a simple intepreter, <tt>lli</tt> is also has debugger and tracing
337 modes (entered by specifying <tt>-debug</tt> or <tt>-trace</tt> on the
338 command line, respectively).<p>
339
340 <dt><tt><b>llc</b></tt><dd> <tt>llc</tt> is the LLVM backend compiler,
341 which translates LLVM bytecode to a SPARC assembly file.<p>
342
343 <dt><tt><b>llvmgcc</b></tt><dd> <tt>llvmgcc</tt> is a GCC based C frontend
344 that has been retargeted to emit LLVM code as the machine code output. It
345 works just like any other GCC compiler, taking the typical <tt>-c, -S, -E,
346 -o</tt> options that are typically used. The source code for the
347 <tt>llvmgcc</tt> tool is currently not included in the LLVM cvs tree
348 because it is quite large and not very interesting.<p>
349
350 <ol>
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]351 <dt><tt><b>gccas</b></tt><dd> This tool is invoked by the
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]352 <tt>llvmgcc</tt> frontend as the "assembler" part of the compiler. This
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]353 tool actually assembles LLVM assembly to LLVM bytecode,
354 performs a variety of optimizations,
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]355 and outputs LLVM bytecode. Thus when you invoke <tt>llvmgcc -c x.c -o
356 x.o</tt>, you are causing <tt>gccas</tt> to be run, which writes the
357 <tt>x.o</tt> file (which is an LLVM bytecode file that can be
358 disassembled or manipulated just like any other bytecode file). The
359 command line interface to <tt>gccas</tt> is designed to be as close as
360 possible to the <b>system</b> <tt>as</tt> utility so that the gcc
361 frontend itself did not have to be modified to interface to a "wierd"
362 assembler.<p>
363
364 <dt><tt><b>gccld</b></tt><dd> <tt>gccld</tt> links together several llvm
365 bytecode files into one bytecode file and does some optimization. It is
366 the linker invoked by the gcc frontend when multiple .o files need to be
367 linked together. Like <tt>gccas</tt> the command line interface of
368 <tt>gccld</tt> is designed to match the system linker, to aid
369 interfacing with the GCC frontend.<p>
370 </ol>
371
372 <dt><tt><b>opt</b></tt><dd> <tt>opt</tt> reads llvm bytecode, applies a
373 series of LLVM to LLVM transformations (which are specified on the command
374 line), and then outputs the resultant bytecode. The '<tt>opt --help</tt>'
375 command is a good way to get a list of the program transformations
376 available in LLVM.<p>
377
378
379 <dt><tt><b>analyze</b></tt><dd> <tt>analyze</tt> is used to run a specific
380 analysis on an input LLVM bytecode file and print out the results. It is
381 primarily useful for debugging analyses, or familiarizing yourself with
382 what an analysis does.<p>
383
384 </dl>
385
386 <!--=====================================================================-->
387 <h2><a name="tutorial">An example using the LLVM tool chain</h2>
388 <!--=====================================================================-->
389
390 <ol>
391 <li>First, create a simple C file, name it 'hello.c':
392 <pre>
393 #include &lt;stdio.h&gt;
394 int main() {
395 printf("hello world\n");
396 return 0;
397 }
398 </pre>
399
400 <li>Next, compile the C file into a LLVM bytecode file:<p>
401
402 <tt>% llvmgcc hello.c -o hello</tt><p>
403
404 This will create two result files: <tt>hello</tt> and
405 <tt>hello.bc</tt>. The <tt>hello.bc</tt> is the LLVM bytecode that
406 corresponds the the compiled program and the library facilities that it
407 required. <tt>hello</tt> is a simple shell script that runs the bytecode
408 file with <tt>lli</tt>, making the result directly executable.<p>
409
410 <li>Run the program. To make sure the program ran, execute one of the
411 following commands:<p>
412
413 <tt>% ./hello</tt><p>
414
415 or<p>
416
417 <tt>% lli hello.bc</tt><p>
418
419 <li>Use the <tt>dis</tt> utility to take a look at the LLVM assembly
420 code:<p>
421
422 <tt>% dis < hello.bc | less</tt><p>
423
424 <li>Compile the program to native Sparc assembly using the code
425 generator:<p>
426
427 <tt>% llc hello.bc -o hello.s</tt><p>
428
429 <li>Assemble the native sparc assemble file into a program:<p>
430
431 <tt>% /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.sparc</tt><p>
432
433 <li>Execute the native sparc program:<p>
434
435 <tt>% ./hello.sparc</tt><p>
436
437 </ol>
438
439
440 <!--=====================================================================-->
441 <h2><a name="links">Links</a></h2>
442 <!--=====================================================================-->
443
444 <p>This document is just an <b>introduction</b> to how to use LLVM to do
445 some simple things... there are many more interesting and complicated things
446 that you can do that aren't documented here (but we'll gladly accept a patch
447 if you want to write something up!). For more information about LLVM, check
448 out:</p>
449
450 <ul>
451 <li><a href="http://llvm.cs.uiuc.edu/">LLVM homepage</a></li>
452 <li><a href="http://tank.cs.uiuc.edu/doxygen/">LLVM doxygen tree</a></li>
453 </ul>
454
455 <hr>
456
457 If you have any questions or run into any snags (or you have any
Chris Lattner1db872d2002-09-06 16:26:13 +0000[diff] [blame^]458 additions...), please send an email to
459 <a href="mailto:hldnbrnd@uiuc.edu">Nicholas Hildenbrandt</a> or
460 <a href="mailto:sabre@nondot.org">Chris Lattner</a>.</p>
Chris Lattner7fe7f812002-07-24 19:51:14 +0000[diff] [blame]461
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]462 <!-- Created: Mon Jul 1 02:29:02 CDT 2002 -->
463 <!-- hhmts start -->
Chris Lattnercefbd322002-08-13 21:10:30 +0000[diff] [blame]464Last modified: Tue Aug 13 16:09:25 CDT 2002
Guochun Shif4688a82002-07-17 23:05:56 +0000[diff] [blame]465<!-- hhmts end -->
466 </body>
467</html>