blob: f3a5891b1521859136096c2c56a280cc39bd446f [file] [log] [blame]
Misha Brukman13fd15c2004-01-15 00:14:41 +00001<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
Chris Lattner261efe92003-11-25 01:02:51 +00003<html>
4<head>
5 <title>LLVM Programmer's Manual</title>
Misha Brukman13fd15c2004-01-15 00:14:41 +00006 <link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattner261efe92003-11-25 01:02:51 +00007</head>
Misha Brukman13fd15c2004-01-15 00:14:41 +00008<body>
9
10<div class="doc_title">
11 LLVM Programmer's Manual
12</div>
13
Chris Lattner9355b472002-09-06 02:50:58 +000014<ol>
Misha Brukman13fd15c2004-01-15 00:14:41 +000015 <li><a href="#introduction">Introduction</a></li>
Chris Lattner9355b472002-09-06 02:50:58 +000016 <li><a href="#general">General Information</a>
Chris Lattner261efe92003-11-25 01:02:51 +000017 <ul>
18 <li><a href="#stl">The C++ Standard Template Library</a><!--
Chris Lattner986e0c92002-09-22 19:38:40 +000019 <li>The <tt>-time-passes</tt> option
20 <li>How to use the LLVM Makefile system
21 <li>How to write a regression test
Chris Lattner261efe92003-11-25 01:02:51 +000022--> </li>
Chris Lattner84b7f8d2003-08-01 22:20:59 +000023 </ul>
Chris Lattner261efe92003-11-25 01:02:51 +000024 </li>
25 <li><a href="#apis">Important and useful LLVM APIs</a>
26 <ul>
27 <li><a href="#isa">The <tt>isa&lt;&gt;</tt>, <tt>cast&lt;&gt;</tt>
28and <tt>dyn_cast&lt;&gt;</tt> templates</a> </li>
29 <li><a href="#DEBUG">The <tt>DEBUG()</tt> macro &amp; <tt>-debug</tt>
30option</a>
31 <ul>
32 <li><a href="#DEBUG_TYPE">Fine grained debug info with <tt>DEBUG_TYPE</tt>
33and the <tt>-debug-only</tt> option</a> </li>
34 </ul>
35 </li>
36 <li><a href="#Statistic">The <tt>Statistic</tt> template &amp; <tt>-stats</tt>
37option</a><!--
Chris Lattner986e0c92002-09-22 19:38:40 +000038 <li>The <tt>InstVisitor</tt> template
39 <li>The general graph API
Chris Lattner261efe92003-11-25 01:02:51 +000040--> </li>
41 </ul>
42 </li>
Chris Lattnerae7f7592002-09-06 18:31:18 +000043 <li><a href="#common">Helpful Hints for Common Operations</a>
Chris Lattnerae7f7592002-09-06 18:31:18 +000044 <ul>
Chris Lattner261efe92003-11-25 01:02:51 +000045 <li><a href="#inspection">Basic Inspection and Traversal Routines</a>
46 <ul>
47 <li><a href="#iterate_function">Iterating over the <tt>BasicBlock</tt>s
48in a <tt>Function</tt></a> </li>
49 <li><a href="#iterate_basicblock">Iterating over the <tt>Instruction</tt>s
50in a <tt>BasicBlock</tt></a> </li>
51 <li><a href="#iterate_institer">Iterating over the <tt>Instruction</tt>s
52in a <tt>Function</tt></a> </li>
53 <li><a href="#iterate_convert">Turning an iterator into a
54class pointer</a> </li>
55 <li><a href="#iterate_complex">Finding call sites: a more
56complex example</a> </li>
57 <li><a href="#calls_and_invokes">Treating calls and invokes
58the same way</a> </li>
59 <li><a href="#iterate_chains">Iterating over def-use &amp;
60use-def chains</a> </li>
61 </ul>
62 </li>
63 <li><a href="#simplechanges">Making simple changes</a>
64 <ul>
65 <li><a href="#schanges_creating">Creating and inserting new
66 <tt>Instruction</tt>s</a> </li>
67 <li><a href="#schanges_deleting">Deleting <tt>Instruction</tt>s</a> </li>
68 <li><a href="#schanges_replacing">Replacing an <tt>Instruction</tt>
69with another <tt>Value</tt></a> </li>
70 </ul>
Chris Lattnerae7f7592002-09-06 18:31:18 +000071<!--
72 <li>Working with the Control Flow Graph
73 <ul>
74 <li>Accessing predecessors and successors of a <tt>BasicBlock</tt>
75 <li>
76 <li>
77 </ul>
Chris Lattner261efe92003-11-25 01:02:51 +000078--> </li>
79 </ul>
80 </li>
Joel Stanley9b96c442002-09-06 21:55:13 +000081 <li><a href="#coreclasses">The Core LLVM Class Hierarchy Reference</a>
Chris Lattner9355b472002-09-06 02:50:58 +000082 <ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +000083 <li><a href="#Value">The <tt>Value</tt> class</a>
84 <ul>
85 <li><a href="#User">The <tt>User</tt> class</a>
Chris Lattner9355b472002-09-06 02:50:58 +000086 <ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +000087 <li><a href="#Instruction">The <tt>Instruction</tt> class</a>
Chris Lattner261efe92003-11-25 01:02:51 +000088 <ul>
Reid Spencer096603a2004-05-26 08:41:35 +000089 <li><a href="#GetElementPtrInst">The <tt>GetElementPtrInst</tt>
90 class</a></li>
Misha Brukman13fd15c2004-01-15 00:14:41 +000091 </ul></li>
Misha Brukman13fd15c2004-01-15 00:14:41 +000092 <li><a href="#Module">The <tt>Module</tt> class</a></li>
Reid Spencer8b2da7a2004-07-18 13:10:31 +000093 <li><a href="#Constant">The <tt>Constant</tt> class</a>
94 <ul>
95 <li><a href="#GlobalValue">The <tt>GlobalValue</tt> class</a>
96 <ul>
97 <li><a href="#BasicBlock">The <tt>BasicBlock</tt>class</a></li>
98 <li><a href="#Function">The <tt>Function</tt> class</a></li>
99 <li><a href="#GlobalVariable">The <tt>GlobalVariable</tt> class
100 </a></li>
101 </ul></li>
102 </ul>
103 </li>
Chris Lattner261efe92003-11-25 01:02:51 +0000104 <li><a href="#Type">The <tt>Type</tt> class</a> </li>
Reid Spencer096603a2004-05-26 08:41:35 +0000105 <li><a href="#Argument">The <tt>Argument</tt> class</a></li>
106 </ul></li>
107 </ul></li>
108 <li><a href="#SymbolTable">The <tt>SymbolTable</tt> class </a></li>
109 <li>The <tt>ilist</tt> and <tt>iplist</tt> classes
110 <ul>
111 <li>Creating, inserting, moving and deleting from LLVM lists </li>
112 </ul>
113 </li>
114 <li>Important iterator invalidation semantics to be aware of.</li>
Chris Lattner261efe92003-11-25 01:02:51 +0000115 </li>
Chris Lattner9355b472002-09-06 02:50:58 +0000116</ol>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000117
Chris Lattner69bf8a92004-05-23 21:06:58 +0000118<div class="doc_author">
119 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
Chris Lattner94c43592004-05-26 16:52:55 +0000120 <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a>,
121 <a href="mailto:jstanley@cs.uiuc.edu">Joel Stanley</a>, and
122 <a href="mailto:rspencer@x10sys.com">Reid Spencer</a></p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000123</div>
124
Chris Lattner9355b472002-09-06 02:50:58 +0000125<!-- *********************************************************************** -->
Misha Brukman13fd15c2004-01-15 00:14:41 +0000126<div class="doc_section">
127 <a name="introduction">Introduction </a>
128</div>
Chris Lattner9355b472002-09-06 02:50:58 +0000129<!-- *********************************************************************** -->
Misha Brukman13fd15c2004-01-15 00:14:41 +0000130
131<div class="doc_text">
132
133<p>This document is meant to highlight some of the important classes and
Chris Lattner261efe92003-11-25 01:02:51 +0000134interfaces available in the LLVM source-base. This manual is not
135intended to explain what LLVM is, how it works, and what LLVM code looks
136like. It assumes that you know the basics of LLVM and are interested
137in writing transformations or otherwise analyzing or manipulating the
Misha Brukman13fd15c2004-01-15 00:14:41 +0000138code.</p>
139
140<p>This document should get you oriented so that you can find your
Chris Lattner261efe92003-11-25 01:02:51 +0000141way in the continuously growing source code that makes up the LLVM
142infrastructure. Note that this manual is not intended to serve as a
143replacement for reading the source code, so if you think there should be
144a method in one of these classes to do something, but it's not listed,
145check the source. Links to the <a href="/doxygen/">doxygen</a> sources
146are provided to make this as easy as possible.</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000147
148<p>The first section of this document describes general information that is
149useful to know when working in the LLVM infrastructure, and the second describes
150the Core LLVM classes. In the future this manual will be extended with
151information describing how to use extension libraries, such as dominator
152information, CFG traversal routines, and useful utilities like the <tt><a
153href="/doxygen/InstVisitor_8h-source.html">InstVisitor</a></tt> template.</p>
154
155</div>
156
Chris Lattner9355b472002-09-06 02:50:58 +0000157<!-- *********************************************************************** -->
Misha Brukman13fd15c2004-01-15 00:14:41 +0000158<div class="doc_section">
159 <a name="general">General Information</a>
160</div>
161<!-- *********************************************************************** -->
162
163<div class="doc_text">
164
165<p>This section contains general information that is useful if you are working
166in the LLVM source-base, but that isn't specific to any particular API.</p>
167
168</div>
169
170<!-- ======================================================================= -->
171<div class="doc_subsection">
172 <a name="stl">The C++ Standard Template Library</a>
173</div>
174
175<div class="doc_text">
176
177<p>LLVM makes heavy use of the C++ Standard Template Library (STL),
Chris Lattner261efe92003-11-25 01:02:51 +0000178perhaps much more than you are used to, or have seen before. Because of
179this, you might want to do a little background reading in the
180techniques used and capabilities of the library. There are many good
181pages that discuss the STL, and several books on the subject that you
Misha Brukman13fd15c2004-01-15 00:14:41 +0000182can get, so it will not be discussed in this document.</p>
183
184<p>Here are some useful links:</p>
185
186<ol>
187
188<li><a href="http://www.dinkumware.com/refxcpp.html">Dinkumware C++ Library
189reference</a> - an excellent reference for the STL and other parts of the
190standard C++ library.</li>
191
192<li><a href="http://www.tempest-sw.com/cpp/">C++ In a Nutshell</a> - This is an
Tanya Lattner09cf73c2004-06-22 04:24:55 +0000193O'Reilly book in the making. It has a decent
194Standard Library
195Reference that rivals Dinkumware's, and is unfortunately no longer free since the book has been
Misha Brukman13fd15c2004-01-15 00:14:41 +0000196published.</li>
197
198<li><a href="http://www.parashift.com/c++-faq-lite/">C++ Frequently Asked
199Questions</a></li>
200
201<li><a href="http://www.sgi.com/tech/stl/">SGI's STL Programmer's Guide</a> -
202Contains a useful <a
203href="http://www.sgi.com/tech/stl/stl_introduction.html">Introduction to the
204STL</a>.</li>
205
206<li><a href="http://www.research.att.com/%7Ebs/C++.html">Bjarne Stroustrup's C++
207Page</a></li>
208
Reid Spencer096603a2004-05-26 08:41:35 +0000209<li><a href="http://www.linux.com.cn/Bruce_Eckel/TICPPv2/Contents.htm">
210Bruce Eckel's Thinking in C++, 2nd ed. Volume 2 Revision 4.0 (even better, get
211the book).</a></li>
212
Misha Brukman13fd15c2004-01-15 00:14:41 +0000213</ol>
214
215<p>You are also encouraged to take a look at the <a
216href="CodingStandards.html">LLVM Coding Standards</a> guide which focuses on how
217to write maintainable code more than where to put your curly braces.</p>
218
219</div>
220
221<!-- ======================================================================= -->
222<div class="doc_subsection">
223 <a name="stl">Other useful references</a>
224</div>
225
226<div class="doc_text">
227
Misha Brukman13fd15c2004-01-15 00:14:41 +0000228<ol>
229<li><a href="http://www.psc.edu/%7Esemke/cvs_branches.html">CVS
Chris Lattner261efe92003-11-25 01:02:51 +0000230Branch and Tag Primer</a></li>
Misha Brukmana0f71e42004-06-18 18:39:00 +0000231<li><a href="http://www.fortran-2000.com/ArnaudRecipes/sharedlib.html">Using
232static and shared libraries across platforms</a></li>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000233</ol>
234
235</div>
236
Chris Lattner9355b472002-09-06 02:50:58 +0000237<!-- *********************************************************************** -->
Misha Brukman13fd15c2004-01-15 00:14:41 +0000238<div class="doc_section">
239 <a name="apis">Important and useful LLVM APIs</a>
240</div>
241<!-- *********************************************************************** -->
242
243<div class="doc_text">
244
245<p>Here we highlight some LLVM APIs that are generally useful and good to
246know about when writing transformations.</p>
247
248</div>
249
250<!-- ======================================================================= -->
251<div class="doc_subsection">
252 <a name="isa">The isa&lt;&gt;, cast&lt;&gt; and dyn_cast&lt;&gt; templates</a>
253</div>
254
255<div class="doc_text">
256
257<p>The LLVM source-base makes extensive use of a custom form of RTTI.
Chris Lattner261efe92003-11-25 01:02:51 +0000258These templates have many similarities to the C++ <tt>dynamic_cast&lt;&gt;</tt>
259operator, but they don't have some drawbacks (primarily stemming from
260the fact that <tt>dynamic_cast&lt;&gt;</tt> only works on classes that
261have a v-table). Because they are used so often, you must know what they
262do and how they work. All of these templates are defined in the <a
263 href="/doxygen/Casting_8h-source.html"><tt>Support/Casting.h</tt></a>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000264file (note that you very rarely have to include this file directly).</p>
265
266<dl>
267 <dt><tt>isa&lt;&gt;</tt>: </dt>
268
269 <dd>The <tt>isa&lt;&gt;</tt> operator works exactly like the Java
270 "<tt>instanceof</tt>" operator. It returns true or false depending on whether
271 a reference or pointer points to an instance of the specified class. This can
272 be very useful for constraint checking of various sorts (example below).</dd>
273
274 <dt><tt>cast&lt;&gt;</tt>: </dt>
275
276 <dd>The <tt>cast&lt;&gt;</tt> operator is a "checked cast" operation. It
277 converts a pointer or reference from a base class to a derived cast, causing
278 an assertion failure if it is not really an instance of the right type. This
279 should be used in cases where you have some information that makes you believe
280 that something is of the right type. An example of the <tt>isa&lt;&gt;</tt>
281 and <tt>cast&lt;&gt;</tt> template is:
282
Chris Lattner69bf8a92004-05-23 21:06:58 +0000283 <pre>
284 static bool isLoopInvariant(const <a href="#Value">Value</a> *V, const Loop *L) {
285 if (isa&lt;<a href="#Constant">Constant</a>&gt;(V) || isa&lt;<a href="#Argument">Argument</a>&gt;(V) || isa&lt;<a href="#GlobalValue">GlobalValue</a>&gt;(V))
286 return true;
287
288 <i>// Otherwise, it must be an instruction...</i>
289 return !L-&gt;contains(cast&lt;<a href="#Instruction">Instruction</a>&gt;(V)-&gt;getParent());
290 </pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000291
292 <p>Note that you should <b>not</b> use an <tt>isa&lt;&gt;</tt> test followed
293 by a <tt>cast&lt;&gt;</tt>, for that use the <tt>dyn_cast&lt;&gt;</tt>
294 operator.</p>
295
296 </dd>
297
298 <dt><tt>dyn_cast&lt;&gt;</tt>:</dt>
299
300 <dd>The <tt>dyn_cast&lt;&gt;</tt> operator is a "checking cast" operation. It
301 checks to see if the operand is of the specified type, and if so, returns a
302 pointer to it (this operator does not work with references). If the operand is
303 not of the correct type, a null pointer is returned. Thus, this works very
304 much like the <tt>dynamic_cast</tt> operator in C++, and should be used in the
305 same circumstances. Typically, the <tt>dyn_cast&lt;&gt;</tt> operator is used
306 in an <tt>if</tt> statement or some other flow control statement like this:
307
Chris Lattner69bf8a92004-05-23 21:06:58 +0000308 <pre>
309 if (<a href="#AllocationInst">AllocationInst</a> *AI = dyn_cast&lt;<a href="#AllocationInst">AllocationInst</a>&gt;(Val)) {
310 ...
311 }
312 </pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000313
314 <p> This form of the <tt>if</tt> statement effectively combines together a
315 call to <tt>isa&lt;&gt;</tt> and a call to <tt>cast&lt;&gt;</tt> into one
316 statement, which is very convenient.</p>
317
318 <p> Another common example is:</p>
319
Chris Lattner69bf8a92004-05-23 21:06:58 +0000320 <pre>
321 <i>// Loop over all of the phi nodes in a basic block</i>
322 BasicBlock::iterator BBI = BB-&gt;begin();
323 for (; <a href="#PhiNode">PHINode</a> *PN = dyn_cast&lt;<a href="#PHINode">PHINode</a>&gt;(BBI); ++BBI)
324 std::cerr &lt;&lt; *PN;
325 </pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000326
327 <p>Note that the <tt>dyn_cast&lt;&gt;</tt> operator, like C++'s
328 <tt>dynamic_cast</tt> or Java's <tt>instanceof</tt> operator, can be abused.
329 In particular you should not use big chained <tt>if/then/else</tt> blocks to
330 check for lots of different variants of classes. If you find yourself
331 wanting to do this, it is much cleaner and more efficient to use the
332 InstVisitor class to dispatch over the instruction type directly.</p>
333
Chris Lattner261efe92003-11-25 01:02:51 +0000334 </dd>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000335
Chris Lattner261efe92003-11-25 01:02:51 +0000336 <dt><tt>cast_or_null&lt;&gt;</tt>: </dt>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000337
338 <dd>The <tt>cast_or_null&lt;&gt;</tt> operator works just like the
339 <tt>cast&lt;&gt;</tt> operator, except that it allows for a null pointer as
340 an argument (which it then propagates). This can sometimes be useful,
341 allowing you to combine several null checks into one.</dd>
342
Chris Lattner261efe92003-11-25 01:02:51 +0000343 <dt><tt>dyn_cast_or_null&lt;&gt;</tt>: </dt>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000344
345 <dd>The <tt>dyn_cast_or_null&lt;&gt;</tt> operator works just like the
346 <tt>dyn_cast&lt;&gt;</tt> operator, except that it allows for a null pointer
347 as an argument (which it then propagates). This can sometimes be useful,
348 allowing you to combine several null checks into one.</dd>
349
Chris Lattner261efe92003-11-25 01:02:51 +0000350 </dl>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000351
352<p>These five templates can be used with any classes, whether they have a
353v-table or not. To add support for these templates, you simply need to add
354<tt>classof</tt> static methods to the class you are interested casting
355to. Describing this is currently outside the scope of this document, but there
356are lots of examples in the LLVM source base.</p>
357
358</div>
359
360<!-- ======================================================================= -->
361<div class="doc_subsection">
362 <a name="DEBUG">The <tt>DEBUG()</tt> macro &amp; <tt>-debug</tt> option</a>
363</div>
364
365<div class="doc_text">
366
367<p>Often when working on your pass you will put a bunch of debugging printouts
368and other code into your pass. After you get it working, you want to remove
369it... but you may need it again in the future (to work out new bugs that you run
370across).</p>
371
372<p> Naturally, because of this, you don't want to delete the debug printouts,
373but you don't want them to always be noisy. A standard compromise is to comment
374them out, allowing you to enable them if you need them in the future.</p>
375
376<p>The "<tt><a href="/doxygen/Debug_8h-source.html">Support/Debug.h</a></tt>"
377file provides a macro named <tt>DEBUG()</tt> that is a much nicer solution to
378this problem. Basically, you can put arbitrary code into the argument of the
379<tt>DEBUG</tt> macro, and it is only executed if '<tt>opt</tt>' (or any other
380tool) is run with the '<tt>-debug</tt>' command line argument:</p>
381
Chris Lattner261efe92003-11-25 01:02:51 +0000382 <pre> ... <br> DEBUG(std::cerr &lt;&lt; "I am here!\n");<br> ...<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000383
384<p>Then you can run your pass like this:</p>
385
Chris Lattner261efe92003-11-25 01:02:51 +0000386 <pre> $ opt &lt; a.bc &gt; /dev/null -mypass<br> &lt;no output&gt;<br> $ opt &lt; a.bc &gt; /dev/null -mypass -debug<br> I am here!<br> $<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000387
388<p>Using the <tt>DEBUG()</tt> macro instead of a home-brewed solution allows you
389to not have to create "yet another" command line option for the debug output for
390your pass. Note that <tt>DEBUG()</tt> macros are disabled for optimized builds,
391so they do not cause a performance impact at all (for the same reason, they
392should also not contain side-effects!).</p>
393
394<p>One additional nice thing about the <tt>DEBUG()</tt> macro is that you can
395enable or disable it directly in gdb. Just use "<tt>set DebugFlag=0</tt>" or
396"<tt>set DebugFlag=1</tt>" from the gdb if the program is running. If the
397program hasn't been started yet, you can always just run it with
398<tt>-debug</tt>.</p>
399
400</div>
401
402<!-- _______________________________________________________________________ -->
403<div class="doc_subsubsection">
404 <a name="DEBUG_TYPE">Fine grained debug info with <tt>DEBUG_TYPE()</tt> and
405 the <tt>-debug-only</tt> option</a>
406</div>
407
408<div class="doc_text">
409
410<p>Sometimes you may find yourself in a situation where enabling <tt>-debug</tt>
411just turns on <b>too much</b> information (such as when working on the code
412generator). If you want to enable debug information with more fine-grained
413control, you define the <tt>DEBUG_TYPE</tt> macro and the <tt>-debug</tt> only
414option as follows:</p>
415
Chris Lattner261efe92003-11-25 01:02:51 +0000416 <pre> ...<br> DEBUG(std::cerr &lt;&lt; "No debug type\n");<br> #undef DEBUG_TYPE<br> #define DEBUG_TYPE "foo"<br> DEBUG(std::cerr &lt;&lt; "'foo' debug type\n");<br> #undef DEBUG_TYPE<br> #define DEBUG_TYPE "bar"<br> DEBUG(std::cerr &lt;&lt; "'bar' debug type\n");<br> #undef DEBUG_TYPE<br> #define DEBUG_TYPE ""<br> DEBUG(std::cerr &lt;&lt; "No debug type (2)\n");<br> ...<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000417
418<p>Then you can run your pass like this:</p>
419
Chris Lattner261efe92003-11-25 01:02:51 +0000420 <pre> $ opt &lt; a.bc &gt; /dev/null -mypass<br> &lt;no output&gt;<br> $ opt &lt; a.bc &gt; /dev/null -mypass -debug<br> No debug type<br> 'foo' debug type<br> 'bar' debug type<br> No debug type (2)<br> $ opt &lt; a.bc &gt; /dev/null -mypass -debug-only=foo<br> 'foo' debug type<br> $ opt &lt; a.bc &gt; /dev/null -mypass -debug-only=bar<br> 'bar' debug type<br> $<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000421
422<p>Of course, in practice, you should only set <tt>DEBUG_TYPE</tt> at the top of
423a file, to specify the debug type for the entire module (if you do this before
424you <tt>#include "Support/Debug.h"</tt>, you don't have to insert the ugly
425<tt>#undef</tt>'s). Also, you should use names more meaningful than "foo" and
426"bar", because there is no system in place to ensure that names do not
427conflict. If two different modules use the same string, they will all be turned
428on when the name is specified. This allows, for example, all debug information
429for instruction scheduling to be enabled with <tt>-debug-type=InstrSched</tt>,
Chris Lattner261efe92003-11-25 01:02:51 +0000430even if the source lives in multiple files.</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000431
432</div>
433
434<!-- ======================================================================= -->
435<div class="doc_subsection">
436 <a name="Statistic">The <tt>Statistic</tt> template &amp; <tt>-stats</tt>
437 option</a>
438</div>
439
440<div class="doc_text">
441
442<p>The "<tt><a
443href="/doxygen/Statistic_8h-source.html">Support/Statistic.h</a></tt>" file
444provides a template named <tt>Statistic</tt> that is used as a unified way to
445keep track of what the LLVM compiler is doing and how effective various
446optimizations are. It is useful to see what optimizations are contributing to
447making a particular program run faster.</p>
448
449<p>Often you may run your pass on some big program, and you're interested to see
450how many times it makes a certain transformation. Although you can do this with
451hand inspection, or some ad-hoc method, this is a real pain and not very useful
452for big programs. Using the <tt>Statistic</tt> template makes it very easy to
453keep track of this information, and the calculated information is presented in a
454uniform manner with the rest of the passes being executed.</p>
455
456<p>There are many examples of <tt>Statistic</tt> uses, but the basics of using
457it are as follows:</p>
458
459<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000460 <li>Define your statistic like this:
Chris Lattner261efe92003-11-25 01:02:51 +0000461 <pre>static Statistic&lt;&gt; NumXForms("mypassname", "The # of times I did stuff");<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000462
463 <p>The <tt>Statistic</tt> template can emulate just about any data-type,
464 but if you do not specify a template argument, it defaults to acting like
465 an unsigned int counter (this is usually what you want).</p></li>
466
Chris Lattner261efe92003-11-25 01:02:51 +0000467 <li>Whenever you make a transformation, bump the counter:
Chris Lattner261efe92003-11-25 01:02:51 +0000468 <pre> ++NumXForms; // I did stuff<br></pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000469 </li>
470 </ol>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000471
472 <p>That's all you have to do. To get '<tt>opt</tt>' to print out the
473 statistics gathered, use the '<tt>-stats</tt>' option:</p>
474
Chris Lattner261efe92003-11-25 01:02:51 +0000475 <pre> $ opt -stats -mypassname &lt; program.bc &gt; /dev/null<br> ... statistic output ...<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000476
Chris Lattner261efe92003-11-25 01:02:51 +0000477 <p> When running <tt>gccas</tt> on a C file from the SPEC benchmark
478suite, it gives a report that looks like this:</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000479
Chris Lattner261efe92003-11-25 01:02:51 +0000480 <pre> 7646 bytecodewriter - Number of normal instructions<br> 725 bytecodewriter - Number of oversized instructions<br> 129996 bytecodewriter - Number of bytecode bytes written<br> 2817 raise - Number of insts DCEd or constprop'd<br> 3213 raise - Number of cast-of-self removed<br> 5046 raise - Number of expression trees converted<br> 75 raise - Number of other getelementptr's formed<br> 138 raise - Number of load/store peepholes<br> 42 deadtypeelim - Number of unused typenames removed from symtab<br> 392 funcresolve - Number of varargs functions resolved<br> 27 globaldce - Number of global variables removed<br> 2 adce - Number of basic blocks removed<br> 134 cee - Number of branches revectored<br> 49 cee - Number of setcc instruction eliminated<br> 532 gcse - Number of loads removed<br> 2919 gcse - Number of instructions removed<br> 86 indvars - Number of canonical indvars added<br> 87 indvars - Number of aux indvars removed<br> 25 instcombine - Number of dead inst eliminate<br> 434 instcombine - Number of insts combined<br> 248 licm - Number of load insts hoisted<br> 1298 licm - Number of insts hoisted to a loop pre-header<br> 3 licm - Number of insts hoisted to multiple loop preds (bad, no loop pre-header)<br> 75 mem2reg - Number of alloca's promoted<br> 1444 cfgsimplify - Number of blocks simplified<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000481
482<p>Obviously, with so many optimizations, having a unified framework for this
483stuff is very nice. Making your pass fit well into the framework makes it more
484maintainable and useful.</p>
485
486</div>
487
488<!-- *********************************************************************** -->
489<div class="doc_section">
490 <a name="common">Helpful Hints for Common Operations</a>
491</div>
492<!-- *********************************************************************** -->
493
494<div class="doc_text">
495
496<p>This section describes how to perform some very simple transformations of
497LLVM code. This is meant to give examples of common idioms used, showing the
498practical side of LLVM transformations. <p> Because this is a "how-to" section,
499you should also read about the main classes that you will be working with. The
500<a href="#coreclasses">Core LLVM Class Hierarchy Reference</a> contains details
501and descriptions of the main classes that you should know about.</p>
502
503</div>
504
505<!-- NOTE: this section should be heavy on example code -->
506<!-- ======================================================================= -->
507<div class="doc_subsection">
508 <a name="inspection">Basic Inspection and Traversal Routines</a>
509</div>
510
511<div class="doc_text">
512
513<p>The LLVM compiler infrastructure have many different data structures that may
514be traversed. Following the example of the C++ standard template library, the
515techniques used to traverse these various data structures are all basically the
516same. For a enumerable sequence of values, the <tt>XXXbegin()</tt> function (or
517method) returns an iterator to the start of the sequence, the <tt>XXXend()</tt>
518function returns an iterator pointing to one past the last valid element of the
519sequence, and there is some <tt>XXXiterator</tt> data type that is common
520between the two operations.</p>
521
522<p>Because the pattern for iteration is common across many different aspects of
523the program representation, the standard template library algorithms may be used
524on them, and it is easier to remember how to iterate. First we show a few common
525examples of the data structures that need to be traversed. Other data
526structures are traversed in very similar ways.</p>
527
528</div>
529
530<!-- _______________________________________________________________________ -->
Chris Lattner69bf8a92004-05-23 21:06:58 +0000531<div class="doc_subsubsection">
Misha Brukman13fd15c2004-01-15 00:14:41 +0000532 <a name="iterate_function">Iterating over the </a><a
533 href="#BasicBlock"><tt>BasicBlock</tt></a>s in a <a
534 href="#Function"><tt>Function</tt></a>
535</div>
536
537<div class="doc_text">
538
539<p>It's quite common to have a <tt>Function</tt> instance that you'd like to
540transform in some way; in particular, you'd like to manipulate its
541<tt>BasicBlock</tt>s. To facilitate this, you'll need to iterate over all of
542the <tt>BasicBlock</tt>s that constitute the <tt>Function</tt>. The following is
543an example that prints the name of a <tt>BasicBlock</tt> and the number of
544<tt>Instruction</tt>s it contains:</p>
545
Chris Lattner261efe92003-11-25 01:02:51 +0000546 <pre> // func is a pointer to a Function instance<br> for (Function::iterator i = func-&gt;begin(), e = func-&gt;end(); i != e; ++i) {<br><br> // print out the name of the basic block if it has one, and then the<br> // number of instructions that it contains<br><br> cerr &lt;&lt; "Basic block (name=" &lt;&lt; i-&gt;getName() &lt;&lt; ") has " <br> &lt;&lt; i-&gt;size() &lt;&lt; " instructions.\n";<br> }<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000547
548<p>Note that i can be used as if it were a pointer for the purposes of
Joel Stanley9b96c442002-09-06 21:55:13 +0000549invoking member functions of the <tt>Instruction</tt> class. This is
550because the indirection operator is overloaded for the iterator
Chris Lattner7496ec52003-08-05 22:54:23 +0000551classes. In the above code, the expression <tt>i-&gt;size()</tt> is
Misha Brukman13fd15c2004-01-15 00:14:41 +0000552exactly equivalent to <tt>(*i).size()</tt> just like you'd expect.</p>
553
554</div>
555
556<!-- _______________________________________________________________________ -->
Chris Lattner69bf8a92004-05-23 21:06:58 +0000557<div class="doc_subsubsection">
Misha Brukman13fd15c2004-01-15 00:14:41 +0000558 <a name="iterate_basicblock">Iterating over the </a><a
559 href="#Instruction"><tt>Instruction</tt></a>s in a <a
560 href="#BasicBlock"><tt>BasicBlock</tt></a>
561</div>
562
563<div class="doc_text">
564
565<p>Just like when dealing with <tt>BasicBlock</tt>s in <tt>Function</tt>s, it's
566easy to iterate over the individual instructions that make up
567<tt>BasicBlock</tt>s. Here's a code snippet that prints out each instruction in
568a <tt>BasicBlock</tt>:</p>
569
Chris Lattner261efe92003-11-25 01:02:51 +0000570 <pre> // blk is a pointer to a BasicBlock instance<br> for (BasicBlock::iterator i = blk-&gt;begin(), e = blk-&gt;end(); i != e; ++i)<br> // the next statement works since operator&lt;&lt;(ostream&amp;,...) <br> // is overloaded for Instruction&amp;<br> cerr &lt;&lt; *i &lt;&lt; "\n";<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000571
572<p>However, this isn't really the best way to print out the contents of a
573<tt>BasicBlock</tt>! Since the ostream operators are overloaded for virtually
574anything you'll care about, you could have just invoked the print routine on the
575basic block itself: <tt>cerr &lt;&lt; *blk &lt;&lt; "\n";</tt>.</p>
576
577<p>Note that currently operator&lt;&lt; is implemented for <tt>Value*</tt>, so
578it will print out the contents of the pointer, instead of the pointer value you
579might expect. This is a deprecated interface that will be removed in the
580future, so it's best not to depend on it. To print out the pointer value for
581now, you must cast to <tt>void*</tt>.</p>
582
583</div>
584
585<!-- _______________________________________________________________________ -->
Chris Lattner69bf8a92004-05-23 21:06:58 +0000586<div class="doc_subsubsection">
Misha Brukman13fd15c2004-01-15 00:14:41 +0000587 <a name="iterate_institer">Iterating over the </a><a
588 href="#Instruction"><tt>Instruction</tt></a>s in a <a
589 href="#Function"><tt>Function</tt></a>
590</div>
591
592<div class="doc_text">
593
594<p>If you're finding that you commonly iterate over a <tt>Function</tt>'s
595<tt>BasicBlock</tt>s and then that <tt>BasicBlock</tt>'s <tt>Instruction</tt>s,
596<tt>InstIterator</tt> should be used instead. You'll need to include <a
597href="/doxygen/InstIterator_8h-source.html"><tt>llvm/Support/InstIterator.h</tt></a>,
598and then instantiate <tt>InstIterator</tt>s explicitly in your code. Here's a
Chris Lattner69bf8a92004-05-23 21:06:58 +0000599small example that shows how to dump all instructions in a function to the standard error stream:<p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000600
Chris Lattner69bf8a92004-05-23 21:06:58 +0000601 <pre>#include "<a href="/doxygen/InstIterator_8h-source.html">llvm/Support/InstIterator.h</a>"<br>...<br>// Suppose F is a ptr to a function<br>for (inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)<br> cerr &lt;&lt; *i &lt;&lt; "\n";<br></pre>
Joel Stanleye7be6502002-09-09 15:50:33 +0000602Easy, isn't it? You can also use <tt>InstIterator</tt>s to fill a
603worklist with its initial contents. For example, if you wanted to
Chris Lattner261efe92003-11-25 01:02:51 +0000604initialize a worklist to contain all instructions in a <tt>Function</tt>
605F, all you would need to do is something like:
606 <pre>std::set&lt;Instruction*&gt; worklist;<br>worklist.insert(inst_begin(F), inst_end(F));<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000607
608<p>The STL set <tt>worklist</tt> would now contain all instructions in the
609<tt>Function</tt> pointed to by F.</p>
610
611</div>
612
613<!-- _______________________________________________________________________ -->
614<div class="doc_subsubsection">
615 <a name="iterate_convert">Turning an iterator into a class pointer (and
616 vice-versa)</a>
617</div>
618
619<div class="doc_text">
620
621<p>Sometimes, it'll be useful to grab a reference (or pointer) to a class
Joel Stanley9b96c442002-09-06 21:55:13 +0000622instance when all you've got at hand is an iterator. Well, extracting
Chris Lattner69bf8a92004-05-23 21:06:58 +0000623a reference or a pointer from an iterator is very straight-forward.
Chris Lattner261efe92003-11-25 01:02:51 +0000624Assuming that <tt>i</tt> is a <tt>BasicBlock::iterator</tt> and <tt>j</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000625is a <tt>BasicBlock::const_iterator</tt>:</p>
626
Chris Lattner261efe92003-11-25 01:02:51 +0000627 <pre> Instruction&amp; inst = *i; // grab reference to instruction reference<br> Instruction* pinst = &amp;*i; // grab pointer to instruction reference<br> const Instruction&amp; inst = *j;<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000628
629<p>However, the iterators you'll be working with in the LLVM framework are
630special: they will automatically convert to a ptr-to-instance type whenever they
631need to. Instead of dereferencing the iterator and then taking the address of
632the result, you can simply assign the iterator to the proper pointer type and
633you get the dereference and address-of operation as a result of the assignment
634(behind the scenes, this is a result of overloading casting mechanisms). Thus
635the last line of the last example,</p>
636
Chris Lattner261efe92003-11-25 01:02:51 +0000637 <pre>Instruction* pinst = &amp;*i;</pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000638
639<p>is semantically equivalent to</p>
640
Chris Lattner261efe92003-11-25 01:02:51 +0000641 <pre>Instruction* pinst = i;</pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000642
Chris Lattner69bf8a92004-05-23 21:06:58 +0000643<p>It's also possible to turn a class pointer into the corresponding iterator,
644and this is a constant time operation (very efficient). The following code
645snippet illustrates use of the conversion constructors provided by LLVM
646iterators. By using these, you can explicitly grab the iterator of something
647without actually obtaining it via iteration over some structure:</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000648
Chris Lattner261efe92003-11-25 01:02:51 +0000649 <pre>void printNextInstruction(Instruction* inst) {<br> BasicBlock::iterator it(inst);<br> ++it; // after this line, it refers to the instruction after *inst.<br> if (it != inst-&gt;getParent()-&gt;end()) cerr &lt;&lt; *it &lt;&lt; "\n";<br>}<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000650
Misha Brukman13fd15c2004-01-15 00:14:41 +0000651</div>
652
653<!--_______________________________________________________________________-->
654<div class="doc_subsubsection">
655 <a name="iterate_complex">Finding call sites: a slightly more complex
656 example</a>
657</div>
658
659<div class="doc_text">
660
661<p>Say that you're writing a FunctionPass and would like to count all the
662locations in the entire module (that is, across every <tt>Function</tt>) where a
663certain function (i.e., some <tt>Function</tt>*) is already in scope. As you'll
664learn later, you may want to use an <tt>InstVisitor</tt> to accomplish this in a
Chris Lattner69bf8a92004-05-23 21:06:58 +0000665much more straight-forward manner, but this example will allow us to explore how
Misha Brukman13fd15c2004-01-15 00:14:41 +0000666you'd do it if you didn't have <tt>InstVisitor</tt> around. In pseudocode, this
667is what we want to do:</p>
668
Chris Lattner261efe92003-11-25 01:02:51 +0000669 <pre>initialize callCounter to zero<br>for each Function f in the Module<br> for each BasicBlock b in f<br> for each Instruction i in b<br> if (i is a CallInst and calls the given function)<br> increment callCounter<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000670
671<p>And the actual code is (remember, since we're writing a
672<tt>FunctionPass</tt>, our <tt>FunctionPass</tt>-derived class simply has to
673override the <tt>runOnFunction</tt> method...):</p>
674
Chris Lattner261efe92003-11-25 01:02:51 +0000675 <pre>Function* targetFunc = ...;<br><br>class OurFunctionPass : public FunctionPass {<br> public:<br> OurFunctionPass(): callCounter(0) { }<br><br> virtual runOnFunction(Function&amp; F) {<br> for (Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {<br> for (BasicBlock::iterator i = b-&gt;begin(); ie = b-&gt;end(); i != ie; ++i) {<br> if (<a
676 href="#CallInst">CallInst</a>* callInst = <a href="#isa">dyn_cast</a>&lt;<a
677 href="#CallInst">CallInst</a>&gt;(&amp;*i)) {<br> // we know we've encountered a call instruction, so we<br> // need to determine if it's a call to the<br> // function pointed to by m_func or not.<br> <br> if (callInst-&gt;getCalledFunction() == targetFunc)<br> ++callCounter;<br> }<br> }<br> }<br> <br> private:<br> unsigned callCounter;<br>};<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000678
679</div>
680
Brian Gaekef1972c62003-11-07 19:25:45 +0000681<!--_______________________________________________________________________-->
Misha Brukman13fd15c2004-01-15 00:14:41 +0000682<div class="doc_subsubsection">
683 <a name="calls_and_invokes">Treating calls and invokes the same way</a>
684</div>
685
686<div class="doc_text">
687
688<p>You may have noticed that the previous example was a bit oversimplified in
689that it did not deal with call sites generated by 'invoke' instructions. In
690this, and in other situations, you may find that you want to treat
691<tt>CallInst</tt>s and <tt>InvokeInst</tt>s the same way, even though their
692most-specific common base class is <tt>Instruction</tt>, which includes lots of
693less closely-related things. For these cases, LLVM provides a handy wrapper
694class called <a
Misha Brukman384047f2004-06-03 23:29:12 +0000695href="http://llvm.cs.uiuc.edu/doxygen/classllvm_1_1CallSite.html"><tt>CallSite</tt></a>.
Chris Lattner69bf8a92004-05-23 21:06:58 +0000696It is essentially a wrapper around an <tt>Instruction</tt> pointer, with some
697methods that provide functionality common to <tt>CallInst</tt>s and
Misha Brukman13fd15c2004-01-15 00:14:41 +0000698<tt>InvokeInst</tt>s.</p>
699
Chris Lattner69bf8a92004-05-23 21:06:58 +0000700<p>This class has "value semantics": it should be passed by value, not by
701reference and it should not be dynamically allocated or deallocated using
702<tt>operator new</tt> or <tt>operator delete</tt>. It is efficiently copyable,
703assignable and constructable, with costs equivalents to that of a bare pointer.
704If you look at its definition, it has only a single pointer member.</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000705
706</div>
707
Chris Lattner1a3105b2002-09-09 05:49:39 +0000708<!--_______________________________________________________________________-->
Misha Brukman13fd15c2004-01-15 00:14:41 +0000709<div class="doc_subsubsection">
710 <a name="iterate_chains">Iterating over def-use &amp; use-def chains</a>
711</div>
712
713<div class="doc_text">
714
715<p>Frequently, we might have an instance of the <a
Misha Brukman384047f2004-06-03 23:29:12 +0000716href="/doxygen/structllvm_1_1Value.html">Value Class</a> and we want to
717determine which <tt>User</tt>s use the <tt>Value</tt>. The list of all
718<tt>User</tt>s of a particular <tt>Value</tt> is called a <i>def-use</i> chain.
719For example, let's say we have a <tt>Function*</tt> named <tt>F</tt> to a
720particular function <tt>foo</tt>. Finding all of the instructions that
721<i>use</i> <tt>foo</tt> is as simple as iterating over the <i>def-use</i> chain
722of <tt>F</tt>:</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000723
Chris Lattner261efe92003-11-25 01:02:51 +0000724 <pre>Function* F = ...;<br><br>for (Value::use_iterator i = F-&gt;use_begin(), e = F-&gt;use_end(); i != e; ++i) {<br> if (Instruction *Inst = dyn_cast&lt;Instruction&gt;(*i)) {<br> cerr &lt;&lt; "F is used in instruction:\n";<br> cerr &lt;&lt; *Inst &lt;&lt; "\n";<br> }<br>}<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000725
726<p>Alternately, it's common to have an instance of the <a
Misha Brukman384047f2004-06-03 23:29:12 +0000727href="/doxygen/classllvm_1_1User.html">User Class</a> and need to know what
Misha Brukman13fd15c2004-01-15 00:14:41 +0000728<tt>Value</tt>s are used by it. The list of all <tt>Value</tt>s used by a
729<tt>User</tt> is known as a <i>use-def</i> chain. Instances of class
730<tt>Instruction</tt> are common <tt>User</tt>s, so we might want to iterate over
731all of the values that a particular instruction uses (that is, the operands of
732the particular <tt>Instruction</tt>):</p>
733
Chris Lattner261efe92003-11-25 01:02:51 +0000734 <pre>Instruction* pi = ...;<br><br>for (User::op_iterator i = pi-&gt;op_begin(), e = pi-&gt;op_end(); i != e; ++i) {<br> Value* v = *i;<br> ...<br>}<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000735
Chris Lattner1a3105b2002-09-09 05:49:39 +0000736<!--
737 def-use chains ("finding all users of"): Value::use_begin/use_end
738 use-def chains ("finding all values used"): User::op_begin/op_end [op=operand]
Misha Brukman13fd15c2004-01-15 00:14:41 +0000739-->
740
741</div>
742
743<!-- ======================================================================= -->
744<div class="doc_subsection">
745 <a name="simplechanges">Making simple changes</a>
746</div>
747
748<div class="doc_text">
749
750<p>There are some primitive transformation operations present in the LLVM
Joel Stanley753eb712002-09-11 22:32:24 +0000751infrastructure that are worth knowing about. When performing
Chris Lattner261efe92003-11-25 01:02:51 +0000752transformations, it's fairly common to manipulate the contents of basic
753blocks. This section describes some of the common methods for doing so
Misha Brukman13fd15c2004-01-15 00:14:41 +0000754and gives example code.</p>
755
756</div>
757
Chris Lattner261efe92003-11-25 01:02:51 +0000758<!--_______________________________________________________________________-->
Misha Brukman13fd15c2004-01-15 00:14:41 +0000759<div class="doc_subsubsection">
760 <a name="schanges_creating">Creating and inserting new
761 <tt>Instruction</tt>s</a>
762</div>
763
764<div class="doc_text">
765
766<p><i>Instantiating Instructions</i></p>
767
Chris Lattner69bf8a92004-05-23 21:06:58 +0000768<p>Creation of <tt>Instruction</tt>s is straight-forward: simply call the
Misha Brukman13fd15c2004-01-15 00:14:41 +0000769constructor for the kind of instruction to instantiate and provide the necessary
770parameters. For example, an <tt>AllocaInst</tt> only <i>requires</i> a
771(const-ptr-to) <tt>Type</tt>. Thus:</p>
772
773<pre>AllocaInst* ai = new AllocaInst(Type::IntTy);</pre>
774
775<p>will create an <tt>AllocaInst</tt> instance that represents the allocation of
776one integer in the current stack frame, at runtime. Each <tt>Instruction</tt>
777subclass is likely to have varying default parameters which change the semantics
778of the instruction, so refer to the <a
Misha Brukman31ca1de2004-06-03 23:35:54 +0000779href="/doxygen/classllvm_1_1Instruction.html">doxygen documentation for the subclass of
Misha Brukman13fd15c2004-01-15 00:14:41 +0000780Instruction</a> that you're interested in instantiating.</p>
781
782<p><i>Naming values</i></p>
783
784<p>It is very useful to name the values of instructions when you're able to, as
785this facilitates the debugging of your transformations. If you end up looking
786at generated LLVM machine code, you definitely want to have logical names
787associated with the results of instructions! By supplying a value for the
788<tt>Name</tt> (default) parameter of the <tt>Instruction</tt> constructor, you
789associate a logical name with the result of the instruction's execution at
790runtime. For example, say that I'm writing a transformation that dynamically
791allocates space for an integer on the stack, and that integer is going to be
792used as some kind of index by some other code. To accomplish this, I place an
793<tt>AllocaInst</tt> at the first point in the first <tt>BasicBlock</tt> of some
794<tt>Function</tt>, and I'm intending to use it within the same
795<tt>Function</tt>. I might do:</p>
796
797 <pre>AllocaInst* pa = new AllocaInst(Type::IntTy, 0, "indexLoc");</pre>
798
799<p>where <tt>indexLoc</tt> is now the logical name of the instruction's
800execution value, which is a pointer to an integer on the runtime stack.</p>
801
802<p><i>Inserting instructions</i></p>
803
804<p>There are essentially two ways to insert an <tt>Instruction</tt>
805into an existing sequence of instructions that form a <tt>BasicBlock</tt>:</p>
806
Joel Stanley9dd1ad62002-09-18 03:17:23 +0000807<ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000808 <li>Insertion into an explicit instruction list
809
810 <p>Given a <tt>BasicBlock* pb</tt>, an <tt>Instruction* pi</tt> within that
811 <tt>BasicBlock</tt>, and a newly-created instruction we wish to insert
812 before <tt>*pi</tt>, we do the following: </p>
813
Alkis Evlogimenos9a5dc4f2004-05-27 00:57:51 +0000814 <pre> BasicBlock *pb = ...;<br> Instruction *pi = ...;<br> Instruction *newInst = new Instruction(...);<br> pb-&gt;getInstList().insert(pi, newInst); // inserts newInst before pi in pb<br></pre>
815
816 <p>Appending to the end of a <tt>BasicBlock</tt> is so common that
817 the <tt>Instruction</tt> class and <tt>Instruction</tt>-derived
818 classes provide constructors which take a pointer to a
819 <tt>BasicBlock</tt> to be appended to. For example code that
820 looked like: </p>
821
822 <pre> BasicBlock *pb = ...;<br> Instruction *newInst = new Instruction(...);<br> pb-&gt;getInstList().push_back(newInst); // appends newInst to pb<br></pre>
823
824 <p>becomes: </p>
825
826 <pre> BasicBlock *pb = ...;<br> Instruction *newInst = new Instruction(..., pb);<br></pre>
827
828 <p>which is much cleaner, especially if you are creating
829 long instruction streams.</p></li>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000830
831 <li>Insertion into an implicit instruction list
832
833 <p><tt>Instruction</tt> instances that are already in <tt>BasicBlock</tt>s
834 are implicitly associated with an existing instruction list: the instruction
835 list of the enclosing basic block. Thus, we could have accomplished the same
836 thing as the above code without being given a <tt>BasicBlock</tt> by doing:
837 </p>
838
839 <pre> Instruction *pi = ...;<br> Instruction *newInst = new Instruction(...);<br> pi-&gt;getParent()-&gt;getInstList().insert(pi, newInst);<br></pre>
840
841 <p>In fact, this sequence of steps occurs so frequently that the
842 <tt>Instruction</tt> class and <tt>Instruction</tt>-derived classes provide
843 constructors which take (as a default parameter) a pointer to an
844 <tt>Instruction</tt> which the newly-created <tt>Instruction</tt> should
845 precede. That is, <tt>Instruction</tt> constructors are capable of
846 inserting the newly-created instance into the <tt>BasicBlock</tt> of a
847 provided instruction, immediately before that instruction. Using an
848 <tt>Instruction</tt> constructor with a <tt>insertBefore</tt> (default)
849 parameter, the above code becomes:</p>
850
851 <pre>Instruction* pi = ...;<br>Instruction* newInst = new Instruction(..., pi);<br></pre>
852
853 <p>which is much cleaner, especially if you're creating a lot of
854instructions and adding them to <tt>BasicBlock</tt>s.</p></li>
855</ul>
856
857</div>
858
859<!--_______________________________________________________________________-->
860<div class="doc_subsubsection">
861 <a name="schanges_deleting">Deleting <tt>Instruction</tt>s</a>
862</div>
863
864<div class="doc_text">
865
866<p>Deleting an instruction from an existing sequence of instructions that form a
Chris Lattner69bf8a92004-05-23 21:06:58 +0000867<a href="#BasicBlock"><tt>BasicBlock</tt></a> is very straight-forward. First,
Misha Brukman13fd15c2004-01-15 00:14:41 +0000868you must have a pointer to the instruction that you wish to delete. Second, you
869need to obtain the pointer to that instruction's basic block. You use the
870pointer to the basic block to get its list of instructions and then use the
871erase function to remove your instruction. For example:</p>
872
Chris Lattner261efe92003-11-25 01:02:51 +0000873 <pre> <a href="#Instruction">Instruction</a> *I = .. ;<br> <a
874 href="#BasicBlock">BasicBlock</a> *BB = I-&gt;getParent();<br> BB-&gt;getInstList().erase(I);<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000875
876</div>
877
878<!--_______________________________________________________________________-->
879<div class="doc_subsubsection">
880 <a name="schanges_replacing">Replacing an <tt>Instruction</tt> with another
881 <tt>Value</tt></a>
882</div>
883
884<div class="doc_text">
885
886<p><i>Replacing individual instructions</i></p>
887
888<p>Including "<a href="/doxygen/BasicBlockUtils_8h-source.html">llvm/Transforms/Utils/BasicBlockUtils.h</a>"
Chris Lattner261efe92003-11-25 01:02:51 +0000889permits use of two very useful replace functions: <tt>ReplaceInstWithValue</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000890and <tt>ReplaceInstWithInst</tt>.</p>
891
Chris Lattner261efe92003-11-25 01:02:51 +0000892<h4><a name="schanges_deleting">Deleting <tt>Instruction</tt>s</a></h4>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000893
Chris Lattner261efe92003-11-25 01:02:51 +0000894<ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000895 <li><tt>ReplaceInstWithValue</tt>
896
897 <p>This function replaces all uses (within a basic block) of a given
898 instruction with a value, and then removes the original instruction. The
899 following example illustrates the replacement of the result of a particular
900 <tt>AllocaInst</tt> that allocates memory for a single integer with an null
901 pointer to an integer.</p>
902
903 <pre>AllocaInst* instToReplace = ...;<br>BasicBlock::iterator ii(instToReplace);<br>ReplaceInstWithValue(instToReplace-&gt;getParent()-&gt;getInstList(), ii,<br> Constant::getNullValue(PointerType::get(Type::IntTy)));<br></pre></li>
904
905 <li><tt>ReplaceInstWithInst</tt>
906
907 <p>This function replaces a particular instruction with another
908 instruction. The following example illustrates the replacement of one
909 <tt>AllocaInst</tt> with another.</p>
910
911 <pre>AllocaInst* instToReplace = ...;<br>BasicBlock::iterator ii(instToReplace);<br>ReplaceInstWithInst(instToReplace-&gt;getParent()-&gt;getInstList(), ii,<br> new AllocaInst(Type::IntTy, 0, "ptrToReplacedInt"));<br></pre></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000912</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000913
914<p><i>Replacing multiple uses of <tt>User</tt>s and <tt>Value</tt>s</i></p>
915
916<p>You can use <tt>Value::replaceAllUsesWith</tt> and
917<tt>User::replaceUsesOfWith</tt> to change more than one use at a time. See the
Misha Brukman384047f2004-06-03 23:29:12 +0000918doxygen documentation for the <a href="/doxygen/structllvm_1_1Value.html">Value Class</a>
919and <a href="/doxygen/classllvm_1_1User.html">User Class</a>, respectively, for more
Misha Brukman13fd15c2004-01-15 00:14:41 +0000920information.</p>
921
922<!-- Value::replaceAllUsesWith User::replaceUsesOfWith Point out:
923include/llvm/Transforms/Utils/ especially BasicBlockUtils.h with:
924ReplaceInstWithValue, ReplaceInstWithInst -->
925
926</div>
927
Chris Lattner9355b472002-09-06 02:50:58 +0000928<!-- *********************************************************************** -->
Misha Brukman13fd15c2004-01-15 00:14:41 +0000929<div class="doc_section">
930 <a name="coreclasses">The Core LLVM Class Hierarchy Reference </a>
931</div>
932<!-- *********************************************************************** -->
933
934<div class="doc_text">
935
936<p>The Core LLVM classes are the primary means of representing the program
Chris Lattner261efe92003-11-25 01:02:51 +0000937being inspected or transformed. The core LLVM classes are defined in
938header files in the <tt>include/llvm/</tt> directory, and implemented in
Misha Brukman13fd15c2004-01-15 00:14:41 +0000939the <tt>lib/VMCore</tt> directory.</p>
940
941</div>
942
943<!-- ======================================================================= -->
944<div class="doc_subsection">
945 <a name="Value">The <tt>Value</tt> class</a>
946</div>
947
948<div>
949
950<p><tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt>
951<br>
Misha Brukman384047f2004-06-03 23:29:12 +0000952doxygen info: <a href="/doxygen/structllvm_1_1Value.html">Value Class</a></p>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000953
954<p>The <tt>Value</tt> class is the most important class in the LLVM Source
955base. It represents a typed value that may be used (among other things) as an
956operand to an instruction. There are many different types of <tt>Value</tt>s,
957such as <a href="#Constant"><tt>Constant</tt></a>s,<a
958href="#Argument"><tt>Argument</tt></a>s. Even <a
959href="#Instruction"><tt>Instruction</tt></a>s and <a
960href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.</p>
961
962<p>A particular <tt>Value</tt> may be used many times in the LLVM representation
963for a program. For example, an incoming argument to a function (represented
964with an instance of the <a href="#Argument">Argument</a> class) is "used" by
965every instruction in the function that references the argument. To keep track
966of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
967href="#User"><tt>User</tt></a>s that is using it (the <a
968href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
969graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
970def-use information in the program, and is accessible through the <tt>use_</tt>*
971methods, shown below.</p>
972
973<p>Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed,
974and this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
975method. In addition, all LLVM values can be named. The "name" of the
976<tt>Value</tt> is a symbolic string printed in the LLVM code:</p>
977
Chris Lattner261efe92003-11-25 01:02:51 +0000978 <pre> %<b>foo</b> = add int 1, 2<br></pre>
Misha Brukman13fd15c2004-01-15 00:14:41 +0000979
980<p><a name="#nameWarning">The name of this instruction is "foo".</a> <b>NOTE</b>
981that the name of any value may be missing (an empty string), so names should
982<b>ONLY</b> be used for debugging (making the source code easier to read,
983debugging printouts), they should not be used to keep track of values or map
984between them. For this purpose, use a <tt>std::map</tt> of pointers to the
985<tt>Value</tt> itself instead.</p>
986
987<p>One important aspect of LLVM is that there is no distinction between an SSA
988variable and the operation that produces it. Because of this, any reference to
989the value produced by an instruction (or the value available as an incoming
Chris Lattnerd5fc4fc2004-03-18 14:58:55 +0000990argument, for example) is represented as a direct pointer to the instance of
991the class that
Misha Brukman13fd15c2004-01-15 00:14:41 +0000992represents this value. Although this may take some getting used to, it
993simplifies the representation and makes it easier to manipulate.</p>
994
995</div>
996
997<!-- _______________________________________________________________________ -->
998<div class="doc_subsubsection">
999 <a name="m_Value">Important Public Members of the <tt>Value</tt> class</a>
1000</div>
1001
1002<div class="doc_text">
1003
Chris Lattner261efe92003-11-25 01:02:51 +00001004<ul>
1005 <li><tt>Value::use_iterator</tt> - Typedef for iterator over the
1006use-list<br>
1007 <tt>Value::use_const_iterator</tt> - Typedef for const_iterator over
1008the use-list<br>
1009 <tt>unsigned use_size()</tt> - Returns the number of users of the
1010value.<br>
Chris Lattner9355b472002-09-06 02:50:58 +00001011 <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
Chris Lattner261efe92003-11-25 01:02:51 +00001012 <tt>use_iterator use_begin()</tt> - Get an iterator to the start of
1013the use-list.<br>
1014 <tt>use_iterator use_end()</tt> - Get an iterator to the end of the
1015use-list.<br>
1016 <tt><a href="#User">User</a> *use_back()</tt> - Returns the last
1017element in the list.
1018 <p> These methods are the interface to access the def-use
1019information in LLVM. As with all other iterators in LLVM, the naming
1020conventions follow the conventions defined by the <a href="#stl">STL</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +00001021 </li>
1022 <li><tt><a href="#Type">Type</a> *getType() const</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001023 <p>This method returns the Type of the Value.</p>
Chris Lattner261efe92003-11-25 01:02:51 +00001024 </li>
1025 <li><tt>bool hasName() const</tt><br>
Chris Lattner9355b472002-09-06 02:50:58 +00001026 <tt>std::string getName() const</tt><br>
Chris Lattner261efe92003-11-25 01:02:51 +00001027 <tt>void setName(const std::string &amp;Name)</tt>
1028 <p> This family of methods is used to access and assign a name to a <tt>Value</tt>,
1029be aware of the <a href="#nameWarning">precaution above</a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +00001030 </li>
1031 <li><tt>void replaceAllUsesWith(Value *V)</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001032
1033 <p>This method traverses the use list of a <tt>Value</tt> changing all <a
1034 href="#User"><tt>User</tt>s</a> of the current value to refer to
1035 "<tt>V</tt>" instead. For example, if you detect that an instruction always
1036 produces a constant value (for example through constant folding), you can
1037 replace all uses of the instruction with the constant like this:</p>
1038
Chris Lattner261efe92003-11-25 01:02:51 +00001039 <pre> Inst-&gt;replaceAllUsesWith(ConstVal);<br></pre>
Chris Lattner261efe92003-11-25 01:02:51 +00001040</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001041
1042</div>
1043
1044<!-- ======================================================================= -->
1045<div class="doc_subsection">
1046 <a name="User">The <tt>User</tt> class</a>
1047</div>
1048
1049<div class="doc_text">
1050
1051<p>
1052<tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt><br>
Misha Brukman384047f2004-06-03 23:29:12 +00001053doxygen info: <a href="/doxygen/classllvm_1_1User.html">User Class</a><br>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001054Superclass: <a href="#Value"><tt>Value</tt></a></p>
1055
1056<p>The <tt>User</tt> class is the common base class of all LLVM nodes that may
1057refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
1058that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
1059referring to. The <tt>User</tt> class itself is a subclass of
1060<tt>Value</tt>.</p>
1061
1062<p>The operands of a <tt>User</tt> point directly to the LLVM <a
1063href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
1064Single Assignment (SSA) form, there can only be one definition referred to,
1065allowing this direct connection. This connection provides the use-def
1066information in LLVM.</p>
1067
1068</div>
1069
1070<!-- _______________________________________________________________________ -->
1071<div class="doc_subsubsection">
1072 <a name="m_User">Important Public Members of the <tt>User</tt> class</a>
1073</div>
1074
1075<div class="doc_text">
1076
1077<p>The <tt>User</tt> class exposes the operand list in two ways: through
1078an index access interface and through an iterator based interface.</p>
1079
Chris Lattner261efe92003-11-25 01:02:51 +00001080<ul>
Chris Lattner261efe92003-11-25 01:02:51 +00001081 <li><tt>Value *getOperand(unsigned i)</tt><br>
1082 <tt>unsigned getNumOperands()</tt>
1083 <p> These two methods expose the operands of the <tt>User</tt> in a
Misha Brukman13fd15c2004-01-15 00:14:41 +00001084convenient form for direct access.</p></li>
1085
Chris Lattner261efe92003-11-25 01:02:51 +00001086 <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand
1087list<br>
1088 <tt>User::op_const_iterator</tt> <tt>use_iterator op_begin()</tt> -
1089Get an iterator to the start of the operand list.<br>
1090 <tt>use_iterator op_end()</tt> - Get an iterator to the end of the
1091operand list.
1092 <p> Together, these methods make up the iterator based interface to
Misha Brukman13fd15c2004-01-15 00:14:41 +00001093the operands of a <tt>User</tt>.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001094</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001095
1096</div>
1097
1098<!-- ======================================================================= -->
1099<div class="doc_subsection">
1100 <a name="Instruction">The <tt>Instruction</tt> class</a>
1101</div>
1102
1103<div class="doc_text">
1104
1105<p><tt>#include "</tt><tt><a
1106href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt><br>
Misha Brukman31ca1de2004-06-03 23:35:54 +00001107doxygen info: <a href="/doxygen/classllvm_1_1Instruction.html">Instruction Class</a><br>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001108Superclasses: <a href="#User"><tt>User</tt></a>, <a
1109href="#Value"><tt>Value</tt></a></p>
1110
1111<p>The <tt>Instruction</tt> class is the common base class for all LLVM
1112instructions. It provides only a few methods, but is a very commonly used
1113class. The primary data tracked by the <tt>Instruction</tt> class itself is the
1114opcode (instruction type) and the parent <a
1115href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
1116into. To represent a specific type of instruction, one of many subclasses of
1117<tt>Instruction</tt> are used.</p>
1118
1119<p> Because the <tt>Instruction</tt> class subclasses the <a
1120href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
1121way as for other <a href="#User"><tt>User</tt></a>s (with the
1122<tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
1123<tt>op_begin()</tt>/<tt>op_end()</tt> methods).</p> <p> An important file for
1124the <tt>Instruction</tt> class is the <tt>llvm/Instruction.def</tt> file. This
1125file contains some meta-data about the various different types of instructions
1126in LLVM. It describes the enum values that are used as opcodes (for example
1127<tt>Instruction::Add</tt> and <tt>Instruction::SetLE</tt>), as well as the
1128concrete sub-classes of <tt>Instruction</tt> that implement the instruction (for
1129example <tt><a href="#BinaryOperator">BinaryOperator</a></tt> and <tt><a
1130href="#SetCondInst">SetCondInst</a></tt>). Unfortunately, the use of macros in
1131this file confuses doxygen, so these enum values don't show up correctly in the
Misha Brukman31ca1de2004-06-03 23:35:54 +00001132<a href="/doxygen/classllvm_1_1Instruction.html">doxygen output</a>.</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001133
1134</div>
1135
1136<!-- _______________________________________________________________________ -->
1137<div class="doc_subsubsection">
1138 <a name="m_Instruction">Important Public Members of the <tt>Instruction</tt>
1139 class</a>
1140</div>
1141
1142<div class="doc_text">
1143
Chris Lattner261efe92003-11-25 01:02:51 +00001144<ul>
1145 <li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001146 <p>Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that
1147this <tt>Instruction</tt> is embedded into.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001148 <li><tt>bool mayWriteToMemory()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001149 <p>Returns true if the instruction writes to memory, i.e. it is a
1150 <tt>call</tt>,<tt>free</tt>,<tt>invoke</tt>, or <tt>store</tt>.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001151 <li><tt>unsigned getOpcode()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001152 <p>Returns the opcode for the <tt>Instruction</tt>.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001153 <li><tt><a href="#Instruction">Instruction</a> *clone() const</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001154 <p>Returns another instance of the specified instruction, identical
Chris Lattner261efe92003-11-25 01:02:51 +00001155in all ways to the original except that the instruction has no parent
1156(ie it's not embedded into a <a href="#BasicBlock"><tt>BasicBlock</tt></a>),
Misha Brukman13fd15c2004-01-15 00:14:41 +00001157and it has no name</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001158</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001159
1160</div>
1161
1162<!-- ======================================================================= -->
1163<div class="doc_subsection">
1164 <a name="BasicBlock">The <tt>BasicBlock</tt> class</a>
1165</div>
1166
1167<div class="doc_text">
1168
Misha Brukman384047f2004-06-03 23:29:12 +00001169<p><tt>#include "<a
1170href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt><br>
1171doxygen info: <a href="/doxygen/structllvm_1_1BasicBlock.html">BasicBlock
1172Class</a><br>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001173Superclass: <a href="#Value"><tt>Value</tt></a></p>
1174
1175<p>This class represents a single entry multiple exit section of the code,
1176commonly known as a basic block by the compiler community. The
1177<tt>BasicBlock</tt> class maintains a list of <a
1178href="#Instruction"><tt>Instruction</tt></a>s, which form the body of the block.
1179Matching the language definition, the last element of this list of instructions
1180is always a terminator instruction (a subclass of the <a
1181href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).</p>
1182
1183<p>In addition to tracking the list of instructions that make up the block, the
1184<tt>BasicBlock</tt> class also keeps track of the <a
1185href="#Function"><tt>Function</tt></a> that it is embedded into.</p>
1186
1187<p>Note that <tt>BasicBlock</tt>s themselves are <a
1188href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
1189like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
1190<tt>label</tt>.</p>
1191
1192</div>
1193
1194<!-- _______________________________________________________________________ -->
1195<div class="doc_subsubsection">
1196 <a name="m_BasicBlock">Important Public Members of the <tt>BasicBlock</tt>
1197 class</a>
1198</div>
1199
1200<div class="doc_text">
1201
Chris Lattner261efe92003-11-25 01:02:51 +00001202<ul>
1203 <li><tt>BasicBlock(const std::string &amp;Name = "", </tt><tt><a
1204 href="#Function">Function</a> *Parent = 0)</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001205 <p>The <tt>BasicBlock</tt> constructor is used to create new basic
Chris Lattner261efe92003-11-25 01:02:51 +00001206blocks for insertion into a function. The constructor optionally takes
1207a name for the new block, and a <a href="#Function"><tt>Function</tt></a>
1208to insert it into. If the <tt>Parent</tt> parameter is specified, the
1209new <tt>BasicBlock</tt> is automatically inserted at the end of the
1210specified <a href="#Function"><tt>Function</tt></a>, if not specified,
1211the BasicBlock must be manually inserted into the <a href="#Function"><tt>Function</tt></a>.</p>
Chris Lattner261efe92003-11-25 01:02:51 +00001212 </li>
1213 <li><tt>BasicBlock::iterator</tt> - Typedef for instruction list
1214iterator<br>
Chris Lattner9355b472002-09-06 02:50:58 +00001215 <tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
Chris Lattner261efe92003-11-25 01:02:51 +00001216 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,<tt>size()</tt>,<tt>empty()</tt>,<tt>rbegin()</tt>,<tt>rend()
1217- </tt>STL style functions for accessing the instruction list.
1218 <p> These methods and typedefs are forwarding functions that have
1219the same semantics as the standard library methods of the same names.
1220These methods expose the underlying instruction list of a basic block in
1221a way that is easy to manipulate. To get the full complement of
1222container operations (including operations to update the list), you must
Misha Brukman13fd15c2004-01-15 00:14:41 +00001223use the <tt>getInstList()</tt> method.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001224 <li><tt>BasicBlock::InstListType &amp;getInstList()</tt>
1225 <p> This method is used to get access to the underlying container
1226that actually holds the Instructions. This method must be used when
1227there isn't a forwarding function in the <tt>BasicBlock</tt> class for
1228the operation that you would like to perform. Because there are no
1229forwarding functions for "updating" operations, you need to use this if
Misha Brukman13fd15c2004-01-15 00:14:41 +00001230you want to update the contents of a <tt>BasicBlock</tt>.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001231 <li><tt><a href="#Function">Function</a> *getParent()</tt>
1232 <p> Returns a pointer to <a href="#Function"><tt>Function</tt></a>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001233the block is embedded into, or a null pointer if it is homeless.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001234 <li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt>
1235 <p> Returns a pointer to the terminator instruction that appears at
1236the end of the <tt>BasicBlock</tt>. If there is no terminator
1237instruction, or if the last instruction in the block is not a
Misha Brukman13fd15c2004-01-15 00:14:41 +00001238terminator, then a null pointer is returned.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001239</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001240
1241</div>
1242
1243<!-- ======================================================================= -->
1244<div class="doc_subsection">
1245 <a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
1246</div>
1247
1248<div class="doc_text">
1249
1250<p><tt>#include "<a
1251href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt><br>
Misha Brukman384047f2004-06-03 23:29:12 +00001252doxygen info: <a href="/doxygen/classllvm_1_1GlobalValue.html">GlobalValue
1253Class</a><br>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001254Superclasses: <a href="#User"><tt>User</tt></a>, <a
1255href="#Value"><tt>Value</tt></a></p>
1256
1257<p>Global values (<a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
1258href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
1259visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
1260Because they are visible at global scope, they are also subject to linking with
1261other globals defined in different translation units. To control the linking
1262process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
1263<tt>GlobalValue</tt>s know whether they have internal or external linkage, as
Reid Spencer8b2da7a2004-07-18 13:10:31 +00001264defined by the <tt>LinkageTypes</tt> enumeration.</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001265
1266<p>If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
1267<tt>static</tt> in C), it is not visible to code outside the current translation
1268unit, and does not participate in linking. If it has external linkage, it is
1269visible to external code, and does participate in linking. In addition to
1270linkage information, <tt>GlobalValue</tt>s keep track of which <a
1271href="#Module"><tt>Module</tt></a> they are currently part of.</p>
1272
1273<p>Because <tt>GlobalValue</tt>s are memory objects, they are always referred to
1274by their <b>address</b>. As such, the <a href="#Type"><tt>Type</tt></a> of a
1275global is always a pointer to its contents. It is important to remember this
1276when using the <tt>GetElementPtrInst</tt> instruction because this pointer must
1277be dereferenced first. For example, if you have a <tt>GlobalVariable</tt> (a
1278subclass of <tt>GlobalValue)</tt> that is an array of 24 ints, type <tt>[24 x
1279int]</tt>, then the <tt>GlobalVariable</tt> is a pointer to that array. Although
1280the address of the first element of this array and the value of the
1281<tt>GlobalVariable</tt> are the same, they have different types. The
1282<tt>GlobalVariable</tt>'s type is <tt>[24 x int]</tt>. The first element's type
1283is <tt>int.</tt> Because of this, accessing a global value requires you to
1284dereference the pointer with <tt>GetElementPtrInst</tt> first, then its elements
1285can be accessed. This is explained in the <a href="LangRef.html#globalvars">LLVM
1286Language Reference Manual</a>.</p>
1287
1288</div>
1289
1290<!-- _______________________________________________________________________ -->
1291<div class="doc_subsubsection">
1292 <a name="m_GlobalValue">Important Public Members of the <tt>GlobalValue</tt>
1293 class</a>
1294</div>
1295
1296<div class="doc_text">
1297
Chris Lattner261efe92003-11-25 01:02:51 +00001298<ul>
1299 <li><tt>bool hasInternalLinkage() const</tt><br>
Chris Lattner9355b472002-09-06 02:50:58 +00001300 <tt>bool hasExternalLinkage() const</tt><br>
Chris Lattner261efe92003-11-25 01:02:51 +00001301 <tt>void setInternalLinkage(bool HasInternalLinkage)</tt>
1302 <p> These methods manipulate the linkage characteristics of the <tt>GlobalValue</tt>.</p>
1303 <p> </p>
1304 </li>
1305 <li><tt><a href="#Module">Module</a> *getParent()</tt>
1306 <p> This returns the <a href="#Module"><tt>Module</tt></a> that the
Misha Brukman13fd15c2004-01-15 00:14:41 +00001307GlobalValue is currently embedded into.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001308</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001309
1310</div>
1311
1312<!-- ======================================================================= -->
1313<div class="doc_subsection">
1314 <a name="Function">The <tt>Function</tt> class</a>
1315</div>
1316
1317<div class="doc_text">
1318
1319<p><tt>#include "<a
1320href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt><br> doxygen
Misha Brukman31ca1de2004-06-03 23:35:54 +00001321info: <a href="/doxygen/classllvm_1_1Function.html">Function Class</a><br>
1322Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
Misha Brukman13fd15c2004-01-15 00:14:41 +00001323href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a></p>
1324
1325<p>The <tt>Function</tt> class represents a single procedure in LLVM. It is
1326actually one of the more complex classes in the LLVM heirarchy because it must
1327keep track of a large amount of data. The <tt>Function</tt> class keeps track
1328of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
1329href="#Argument"><tt>Argument</tt></a>s, and a <a
1330href="#SymbolTable"><tt>SymbolTable</tt></a>.</p>
1331
1332<p>The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most
1333commonly used part of <tt>Function</tt> objects. The list imposes an implicit
1334ordering of the blocks in the function, which indicate how the code will be
1335layed out by the backend. Additionally, the first <a
1336href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
1337<tt>Function</tt>. It is not legal in LLVM to explicitly branch to this initial
1338block. There are no implicit exit nodes, and in fact there may be multiple exit
1339nodes from a single <tt>Function</tt>. If the <a
1340href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
1341the <tt>Function</tt> is actually a function declaration: the actual body of the
1342function hasn't been linked in yet.</p>
1343
1344<p>In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
1345<tt>Function</tt> class also keeps track of the list of formal <a
1346href="#Argument"><tt>Argument</tt></a>s that the function receives. This
1347container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
1348nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
1349the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.</p>
1350
1351<p>The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used
1352LLVM feature that is only used when you have to look up a value by name. Aside
1353from that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used
1354internally to make sure that there are not conflicts between the names of <a
1355href="#Instruction"><tt>Instruction</tt></a>s, <a
1356href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
1357href="#Argument"><tt>Argument</tt></a>s in the function body.</p>
1358
Reid Spencer8b2da7a2004-07-18 13:10:31 +00001359<p>Note that <tt>Function</tt> is a <a href="#GlobalValue">GlobalValue</a>
1360and therefore also a <a href="#Constant">Constant</a>. The value of the function
1361is its address (after linking) which is guaranteed to be constant.</p>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001362</div>
1363
1364<!-- _______________________________________________________________________ -->
1365<div class="doc_subsubsection">
1366 <a name="m_Function">Important Public Members of the <tt>Function</tt>
1367 class</a>
1368</div>
1369
1370<div class="doc_text">
1371
Chris Lattner261efe92003-11-25 01:02:51 +00001372<ul>
1373 <li><tt>Function(const </tt><tt><a href="#FunctionType">FunctionType</a>
Chris Lattnerac479e52004-08-04 05:10:48 +00001374 *Ty, LinkageTypes Linkage, const std::string &amp;N = "", Module* Parent = 0)</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001375
1376 <p>Constructor used when you need to create new <tt>Function</tt>s to add
1377 the the program. The constructor must specify the type of the function to
Chris Lattnerac479e52004-08-04 05:10:48 +00001378 create and what type of linkage the function should have. The <a
1379 href="#FunctionType"><tt>FunctionType</tt></a> argument
Misha Brukman13fd15c2004-01-15 00:14:41 +00001380 specifies the formal arguments and return value for the function. The same
1381 <a href="#FunctionTypel"><tt>FunctionType</tt></a> value can be used to
1382 create multiple functions. The <tt>Parent</tt> argument specifies the Module
1383 in which the function is defined. If this argument is provided, the function
1384 will automatically be inserted into that module's list of
1385 functions.</p></li>
1386
Chris Lattner261efe92003-11-25 01:02:51 +00001387 <li><tt>bool isExternal()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001388
1389 <p>Return whether or not the <tt>Function</tt> has a body defined. If the
1390 function is "external", it does not have a body, and thus must be resolved
1391 by linking with a function defined in a different translation unit.</p></li>
1392
Chris Lattner261efe92003-11-25 01:02:51 +00001393 <li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
Chris Lattner9355b472002-09-06 02:50:58 +00001394 <tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001395
1396 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
1397 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt>
1398
1399 <p>These are forwarding methods that make it easy to access the contents of
1400 a <tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
1401 list.</p></li>
1402
Chris Lattner261efe92003-11-25 01:02:51 +00001403 <li><tt>Function::BasicBlockListType &amp;getBasicBlockList()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001404
1405 <p>Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This
1406 is necessary to use when you need to update the list or perform a complex
1407 action that doesn't have a forwarding method.</p></li>
1408
Chris Lattner261efe92003-11-25 01:02:51 +00001409 <li><tt>Function::aiterator</tt> - Typedef for the argument list
1410iterator<br>
Chris Lattner9355b472002-09-06 02:50:58 +00001411 <tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001412
1413 <tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
1414 <tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt>
1415
1416 <p>These are forwarding methods that make it easy to access the contents of
1417 a <tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a>
1418 list.</p></li>
1419
Chris Lattner261efe92003-11-25 01:02:51 +00001420 <li><tt>Function::ArgumentListType &amp;getArgumentList()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001421
1422 <p>Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This is
1423 necessary to use when you need to update the list or perform a complex
1424 action that doesn't have a forwarding method.</p></li>
1425
Chris Lattner261efe92003-11-25 01:02:51 +00001426 <li><tt><a href="#BasicBlock">BasicBlock</a> &amp;getEntryBlock()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001427
1428 <p>Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
1429 function. Because the entry block for the function is always the first
1430 block, this returns the first block of the <tt>Function</tt>.</p></li>
1431
Chris Lattner261efe92003-11-25 01:02:51 +00001432 <li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
1433 <tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001434
1435 <p>This traverses the <a href="#Type"><tt>Type</tt></a> of the
1436 <tt>Function</tt> and returns the return type of the function, or the <a
1437 href="#FunctionType"><tt>FunctionType</tt></a> of the actual
1438 function.</p></li>
1439
Chris Lattner261efe92003-11-25 01:02:51 +00001440 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001441
Chris Lattner261efe92003-11-25 01:02:51 +00001442 <p> Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001443 for this <tt>Function</tt>.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001444</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001445
1446</div>
1447
1448<!-- ======================================================================= -->
1449<div class="doc_subsection">
1450 <a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
1451</div>
1452
1453<div class="doc_text">
1454
1455<p><tt>#include "<a
1456href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt>
1457<br>
Tanya Lattnera3da7772004-06-22 08:02:25 +00001458doxygen info: <a href="/doxygen/classllvm_1_1GlobalVariable.html">GlobalVariable
Misha Brukman13fd15c2004-01-15 00:14:41 +00001459Class</a><br> Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
1460href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a></p>
1461
1462<p>Global variables are represented with the (suprise suprise)
1463<tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are also
1464subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such are
1465always referenced by their address (global values must live in memory, so their
1466"name" refers to their address). See <a
1467href="#GlobalValue"><tt>GlobalValue</tt></a> for more on this. Global variables
1468may have an initial value (which must be a <a
1469href="#Constant"><tt>Constant</tt></a>), and if they have an initializer, they
1470may be marked as "constant" themselves (indicating that their contents never
1471change at runtime).</p>
1472
1473</div>
1474
1475<!-- _______________________________________________________________________ -->
1476<div class="doc_subsubsection">
1477 <a name="m_GlobalVariable">Important Public Members of the
1478 <tt>GlobalVariable</tt> class</a>
1479</div>
1480
1481<div class="doc_text">
1482
Chris Lattner261efe92003-11-25 01:02:51 +00001483<ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001484 <li><tt>GlobalVariable(const </tt><tt><a href="#Type">Type</a> *Ty, bool
1485 isConstant, LinkageTypes&amp; Linkage, <a href="#Constant">Constant</a>
1486 *Initializer = 0, const std::string &amp;Name = "", Module* Parent = 0)</tt>
1487
1488 <p>Create a new global variable of the specified type. If
1489 <tt>isConstant</tt> is true then the global variable will be marked as
1490 unchanging for the program. The Linkage parameter specifies the type of
1491 linkage (internal, external, weak, linkonce, appending) for the variable. If
1492 the linkage is InternalLinkage, WeakLinkage, or LinkOnceLinkage,&nbsp; then
1493 the resultant global variable will have internal linkage. AppendingLinkage
1494 concatenates together all instances (in different translation units) of the
1495 variable into a single variable but is only applicable to arrays. &nbsp;See
1496 the <a href="LangRef.html#modulestructure">LLVM Language Reference</a> for
1497 further details on linkage types. Optionally an initializer, a name, and the
1498 module to put the variable into may be specified for the global variable as
1499 well.</p></li>
1500
Chris Lattner261efe92003-11-25 01:02:51 +00001501 <li><tt>bool isConstant() const</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001502
1503 <p>Returns true if this is a global variable that is known not to
1504 be modified at runtime.</p></li>
1505
Chris Lattner261efe92003-11-25 01:02:51 +00001506 <li><tt>bool hasInitializer()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001507
1508 <p>Returns true if this <tt>GlobalVariable</tt> has an intializer.</p></li>
1509
Chris Lattner261efe92003-11-25 01:02:51 +00001510 <li><tt><a href="#Constant">Constant</a> *getInitializer()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001511
1512 <p>Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal
1513 to call this method if there is no initializer.</p></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001514</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001515
1516</div>
1517
1518<!-- ======================================================================= -->
1519<div class="doc_subsection">
1520 <a name="Module">The <tt>Module</tt> class</a>
1521</div>
1522
1523<div class="doc_text">
1524
1525<p><tt>#include "<a
1526href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt><br> doxygen info:
Tanya Lattnera3da7772004-06-22 08:02:25 +00001527<a href="/doxygen/classllvm_1_1Module.html">Module Class</a></p>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001528
1529<p>The <tt>Module</tt> class represents the top level structure present in LLVM
1530programs. An LLVM module is effectively either a translation unit of the
1531original program or a combination of several translation units merged by the
1532linker. The <tt>Module</tt> class keeps track of a list of <a
1533href="#Function"><tt>Function</tt></a>s, a list of <a
1534href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
1535href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
1536helpful member functions that try to make common operations easy.</p>
1537
1538</div>
1539
1540<!-- _______________________________________________________________________ -->
1541<div class="doc_subsubsection">
1542 <a name="m_Module">Important Public Members of the <tt>Module</tt> class</a>
1543</div>
1544
1545<div class="doc_text">
1546
Chris Lattner261efe92003-11-25 01:02:51 +00001547<ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001548 <li><tt>Module::Module(std::string name = "")</tt></li>
Chris Lattner261efe92003-11-25 01:02:51 +00001549</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001550
1551<p>Constructing a <a href="#Module">Module</a> is easy. You can optionally
1552provide a name for it (probably based on the name of the translation unit).</p>
1553
Chris Lattner261efe92003-11-25 01:02:51 +00001554<ul>
1555 <li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
Chris Lattner0377de42002-09-06 14:50:55 +00001556 <tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001557
1558 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
1559 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt>
1560
1561 <p>These are forwarding methods that make it easy to access the contents of
1562 a <tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
1563 list.</p></li>
1564
Chris Lattner261efe92003-11-25 01:02:51 +00001565 <li><tt>Module::FunctionListType &amp;getFunctionList()</tt>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001566
1567 <p> Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
1568 necessary to use when you need to update the list or perform a complex
1569 action that doesn't have a forwarding method.</p>
1570
1571 <p><!-- Global Variable --></p></li>
Chris Lattnerc75ff9a2002-10-01 23:17:09 +00001572</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001573
1574<hr>
1575
Chris Lattnerc75ff9a2002-10-01 23:17:09 +00001576<ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001577 <li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
1578
1579 <tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
1580
1581 <tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
1582 <tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt>
1583
1584 <p> These are forwarding methods that make it easy to access the contents of
1585 a <tt>Module</tt> object's <a
1586 href="#GlobalVariable"><tt>GlobalVariable</tt></a> list.</p></li>
1587
1588 <li><tt>Module::GlobalListType &amp;getGlobalList()</tt>
1589
1590 <p>Returns the list of <a
1591 href="#GlobalVariable"><tt>GlobalVariable</tt></a>s. This is necessary to
1592 use when you need to update the list or perform a complex action that
1593 doesn't have a forwarding method.</p>
1594
1595 <p><!-- Symbol table stuff --> </p></li>
Chris Lattnerc75ff9a2002-10-01 23:17:09 +00001596</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001597
1598<hr>
1599
1600<ul>
1601 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt>
1602
1603 <p>Return a reference to the <a href="#SymbolTable"><tt>SymbolTable</tt></a>
1604 for this <tt>Module</tt>.</p>
1605
1606 <p><!-- Convenience methods --></p></li>
1607</ul>
1608
1609<hr>
1610
1611<ul>
1612 <li><tt><a href="#Function">Function</a> *getFunction(const std::string
1613 &amp;Name, const <a href="#FunctionType">FunctionType</a> *Ty)</tt>
1614
1615 <p>Look up the specified function in the <tt>Module</tt> <a
1616 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
1617 <tt>null</tt>.</p></li>
1618
1619 <li><tt><a href="#Function">Function</a> *getOrInsertFunction(const
1620 std::string &amp;Name, const <a href="#FunctionType">FunctionType</a> *T)</tt>
1621
1622 <p>Look up the specified function in the <tt>Module</tt> <a
1623 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, add an
1624 external declaration for the function and return it.</p></li>
1625
1626 <li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt>
1627
1628 <p>If there is at least one entry in the <a
1629 href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
1630 href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
1631 string.</p></li>
1632
1633 <li><tt>bool addTypeName(const std::string &amp;Name, const <a
1634 href="#Type">Type</a> *Ty)</tt>
1635
1636 <p>Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a>
1637 mapping <tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this
1638 name, true is returned and the <a
1639 href="#SymbolTable"><tt>SymbolTable</tt></a> is not modified.</p></li>
1640</ul>
1641
1642</div>
1643
1644<!-- ======================================================================= -->
1645<div class="doc_subsection">
1646 <a name="Constant">The <tt>Constant</tt> class and subclasses</a>
1647</div>
1648
1649<div class="doc_text">
1650
1651<p>Constant represents a base class for different types of constants. It
1652is subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
1653ConstantArray etc for representing the various types of Constants.</p>
1654
1655</div>
1656
1657<!-- _______________________________________________________________________ -->
1658<div class="doc_subsubsection">
1659 <a name="m_Value">Important Public Methods</a>
1660</div>
1661
1662<div class="doc_text">
1663
Chris Lattnerc75ff9a2002-10-01 23:17:09 +00001664<ul>
Chris Lattner261efe92003-11-25 01:02:51 +00001665 <hr> Important Subclasses of Constant
1666 <p> </p>
1667 <ul>
1668 <li>ConstantSInt : This subclass of Constant represents a signed
1669integer constant.
1670 <ul>
1671 <li><tt>int64_t getValue() const</tt>: Returns the underlying value of
1672this constant. </li>
1673 </ul>
1674 </li>
1675 <li>ConstantUInt : This class represents an unsigned integer.
1676 <ul>
1677 <li><tt>uint64_t getValue() const</tt>: Returns the underlying value
1678of this constant. </li>
1679 </ul>
1680 </li>
1681 <li>ConstantFP : This class represents a floating point constant.
1682 <ul>
1683 <li><tt>double getValue() const</tt>: Returns the underlying value of
1684this constant. </li>
1685 </ul>
1686 </li>
1687 <li>ConstantBool : This represents a boolean constant.
1688 <ul>
1689 <li><tt>bool getValue() const</tt>: Returns the underlying value of
1690this constant. </li>
1691 </ul>
1692 </li>
1693 <li>ConstantArray : This represents a constant array.
1694 <ul>
1695 <li><tt>const std::vector&lt;Use&gt; &amp;getValues() const</tt>:
1696Returns a Vecotr of component constants that makeup this array. </li>
1697 </ul>
1698 </li>
1699 <li>ConstantStruct : This represents a constant struct.
1700 <ul>
1701 <li><tt>const std::vector&lt;Use&gt; &amp;getValues() const</tt>:
1702Returns a Vecotr of component constants that makeup this array. </li>
1703 </ul>
1704 </li>
Reid Spencer8b2da7a2004-07-18 13:10:31 +00001705 <li>GlobalValue : This represents either a global variable or a
1706 function. In either case, the value is a constant fixed address
1707 (after linking).
Chris Lattner261efe92003-11-25 01:02:51 +00001708 </li>
1709 </ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001710 </li>
Chris Lattnerc75ff9a2002-10-01 23:17:09 +00001711</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001712</div>
1713
1714<!-- ======================================================================= -->
1715<div class="doc_subsection">
1716 <a name="Type">The <tt>Type</tt> class and Derived Types</a>
1717</div>
1718
1719<div class="doc_text">
1720
1721<p>Type as noted earlier is also a subclass of a Value class. Any primitive
1722type (like int, short etc) in LLVM is an instance of Type Class. All other
1723types are instances of subclasses of type like FunctionType, ArrayType
1724etc. DerivedType is the interface for all such dervied types including
1725FunctionType, ArrayType, PointerType, StructType. Types can have names. They can
1726be recursive (StructType). There exists exactly one instance of any type
1727structure at a time. This allows using pointer equality of Type *s for comparing
1728types.</p>
1729
1730</div>
1731
1732<!-- _______________________________________________________________________ -->
1733<div class="doc_subsubsection">
1734 <a name="m_Value">Important Public Methods</a>
1735</div>
1736
1737<div class="doc_text">
1738
Chris Lattnerc75ff9a2002-10-01 23:17:09 +00001739<ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001740
Misha Brukman13fd15c2004-01-15 00:14:41 +00001741 <li><tt>bool isSigned() const</tt>: Returns whether an integral numeric type
1742 is signed. This is true for SByteTy, ShortTy, IntTy, LongTy. Note that this is
1743 not true for Float and Double. </li>
1744
1745 <li><tt>bool isUnsigned() const</tt>: Returns whether a numeric type is
1746 unsigned. This is not quite the complement of isSigned... nonnumeric types
1747 return false as they do with isSigned. This returns true for UByteTy,
1748 UShortTy, UIntTy, and ULongTy. </li>
1749
Chris Lattner4573f1b2004-07-08 17:49:37 +00001750 <li><tt>bool isInteger() const</tt>: Equivalent to isSigned() || isUnsigned().</li>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001751
1752 <li><tt>bool isIntegral() const</tt>: Returns true if this is an integral
1753 type, which is either Bool type or one of the Integer types.</li>
1754
1755 <li><tt>bool isFloatingPoint()</tt>: Return true if this is one of the two
1756 floating point types.</li>
1757
Misha Brukman13fd15c2004-01-15 00:14:41 +00001758 <li><tt>isLosslesslyConvertableTo (const Type *Ty) const</tt>: Return true if
1759 this type can be converted to 'Ty' without any reinterpretation of bits. For
Chris Lattner69bf8a92004-05-23 21:06:58 +00001760 example, uint to int or one pointer type to another.</li>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001761
Chris Lattner69bf8a92004-05-23 21:06:58 +00001762<br>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001763 <p>Derived Types</p>
1764
Chris Lattner261efe92003-11-25 01:02:51 +00001765 <ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001766 <li>SequentialType : This is subclassed by ArrayType and PointerType
Chris Lattner261efe92003-11-25 01:02:51 +00001767 <ul>
1768 <li><tt>const Type * getElementType() const</tt>: Returns the type of
1769each of the elements in the sequential type. </li>
1770 </ul>
1771 </li>
1772 <li>ArrayType : This is a subclass of SequentialType and defines
1773interface for array types.
1774 <ul>
1775 <li><tt>unsigned getNumElements() const</tt>: Returns the number of
1776elements in the array. </li>
1777 </ul>
1778 </li>
1779 <li>PointerType : Subclass of SequentialType for pointer types. </li>
1780 <li>StructType : subclass of DerivedTypes for struct types </li>
1781 <li>FunctionType : subclass of DerivedTypes for function types.
1782 <ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001783 <li><tt>bool isVarArg() const</tt>: Returns true if its a vararg
1784 function</li>
Chris Lattner261efe92003-11-25 01:02:51 +00001785 <li><tt> const Type * getReturnType() const</tt>: Returns the
Misha Brukman13fd15c2004-01-15 00:14:41 +00001786 return type of the function.</li>
Chris Lattner261efe92003-11-25 01:02:51 +00001787 <li><tt>const Type * getParamType (unsigned i)</tt>: Returns
Misha Brukman13fd15c2004-01-15 00:14:41 +00001788 the type of the ith parameter.</li>
Chris Lattner261efe92003-11-25 01:02:51 +00001789 <li><tt> const unsigned getNumParams() const</tt>: Returns the
Misha Brukman13fd15c2004-01-15 00:14:41 +00001790 number of formal parameters.</li>
Chris Lattner261efe92003-11-25 01:02:51 +00001791 </ul>
1792 </li>
1793 </ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001794 </li>
Chris Lattnerc75ff9a2002-10-01 23:17:09 +00001795</ul>
Misha Brukman13fd15c2004-01-15 00:14:41 +00001796
1797</div>
1798
1799<!-- ======================================================================= -->
1800<div class="doc_subsection">
1801 <a name="Argument">The <tt>Argument</tt> class</a>
1802</div>
1803
1804<div class="doc_text">
1805
1806<p>This subclass of Value defines the interface for incoming formal
Chris Lattner261efe92003-11-25 01:02:51 +00001807arguments to a function. A Function maitanis a list of its formal
Misha Brukman13fd15c2004-01-15 00:14:41 +00001808arguments. An argument has a pointer to the parent Function.</p>
1809
1810</div>
1811
Reid Spencer096603a2004-05-26 08:41:35 +00001812<!-- ======================================================================= -->
1813<div class="doc_subsection">
1814 <a name="SymbolTable">The <tt>SymbolTable</tt> class</a>
1815</div>
1816<div class="doc_text">
1817<p>This class provides a symbol table that the
1818<a href="#Function"><tt>Function</tt></a> and <a href="#Module">
1819<tt>Module</tt></a> classes use for naming definitions. The symbol table can
1820provide a name for any <a href="#Value"><tt>Value</tt></a> or
1821<a href="#Type"><tt>Type</tt></a>. <tt>SymbolTable</tt> is an abstract data
1822type. It hides the data it contains and provides access to it through a
1823controlled interface.</p>
1824
1825<p>To use the <tt>SymbolTable</tt> well, you need to understand the
1826structure of the information it holds. The class contains two
1827<tt>std::map</tt> objects. The first, <tt>pmap</tt>, is a map of
1828<tt>Type*</tt> to maps of name (<tt>std::string</tt>) to <tt>Value*</tt>.
1829The second, <tt>tmap</tt>, is a map of names to <tt>Type*</tt>. Thus, Values
1830are stored in two-dimensions and accessed by <tt>Type</tt> and name. Types,
1831however, are stored in a single dimension and accessed only by name.</p>
1832
1833<p>The interface of this class provides three basic types of operations:
1834<ol>
1835 <li><em>Accessors</em>. Accessors provide read-only access to information
1836 such as finding a value for a name with the
1837 <a href="#SymbolTable_lookup">lookup</a> method.</li>
1838 <li><em>Mutators</em>. Mutators allow the user to add information to the
1839 <tt>SymbolTable</tt> with methods like
1840 <a href="#SymbolTable_insert"><tt>insert</tt></a>.</li>
1841 <li><em>Iterators</em>. Iterators allow the user to traverse the content
1842 of the symbol table in well defined ways, such as the method
1843 <a href="#SymbolTable_type_begin"><tt>type_begin</tt></a>.</li>
1844</ol>
1845
1846<h3>Accessors</h3>
1847<dl>
1848 <dt><tt>Value* lookup(const Type* Ty, const std::string&amp; name) const</tt>:
1849 </dt>
1850 <dd>The <tt>lookup</tt> method searches the type plane given by the
1851 <tt>Ty</tt> parameter for a <tt>Value</tt> with the provided <tt>name</tt>.
1852 If a suitable <tt>Value</tt> is not found, null is returned.</dd>
1853
1854 <dt><tt>Type* lookupType( const std::string&amp; name) const</tt>:</dt>
1855 <dd>The <tt>lookupType</tt> method searches through the types for a
1856 <tt>Type</tt> with the provided <tt>name</tt>. If a suitable <tt>Type</tt>
1857 is not found, null is returned.</dd>
1858
1859 <dt><tt>bool hasTypes() const</tt>:</dt>
1860 <dd>This function returns true if an entry has been made into the type
1861 map.</dd>
1862
1863 <dt><tt>bool isEmpty() const</tt>:</dt>
1864 <dd>This function returns true if both the value and types maps are
1865 empty</dd>
1866
1867 <dt><tt>std::string get_name(const Value*) const</tt>:</dt>
1868 <dd>This function returns the name of the Value provided or the empty
1869 string if the Value is not in the symbol table.</dd>
1870
1871 <dt><tt>std::string get_name(const Type*) const</tt>:</dt>
1872 <dd>This function returns the name of the Type provided or the empty
1873 string if the Type is not in the symbol table.</dd>
1874</dl>
1875
1876<h3>Mutators</h3>
1877<dl>
1878 <dt><tt>void insert(Value *Val)</tt>:</dt>
1879 <dd>This method adds the provided value to the symbol table. The Value must
1880 have both a name and a type which are extracted and used to place the value
1881 in the correct type plane under the value's name.</dd>
1882
1883 <dt><tt>void insert(const std::string&amp; Name, Value *Val)</tt>:</dt>
1884 <dd> Inserts a constant or type into the symbol table with the specified
1885 name. There can be a many to one mapping between names and constants
1886 or types.</dd>
1887
1888 <dt><tt>void insert(const std::string&amp; Name, Type *Typ)</tt>:</dt>
1889 <dd> Inserts a type into the symbol table with the specified name. There
1890 can be a many-to-one mapping between names and types. This method
1891 allows a type with an existing entry in the symbol table to get
1892 a new name.</dd>
1893
1894 <dt><tt>void remove(Value* Val)</tt>:</dt>
1895 <dd> This method removes a named value from the symbol table. The
1896 type and name of the Value are extracted from \p N and used to
1897 lookup the Value in the correct type plane. If the Value is
1898 not in the symbol table, this method silently ignores the
1899 request.</dd>
1900
1901 <dt><tt>void remove(Type* Typ)</tt>:</dt>
1902 <dd> This method removes a named type from the symbol table. The
1903 name of the type is extracted from \P T and used to look up
1904 the Type in the type map. If the Type is not in the symbol
1905 table, this method silently ignores the request.</dd>
1906
1907 <dt><tt>Value* remove(const std::string&amp; Name, Value *Val)</tt>:</dt>
1908 <dd> Remove a constant or type with the specified name from the
1909 symbol table.</dd>
1910
1911 <dt><tt>Type* remove(const std::string&amp; Name, Type* T)</tt>:</dt>
1912 <dd> Remove a type with the specified name from the symbol table.
1913 Returns the removed Type.</dd>
1914
1915 <dt><tt>Value *value_remove(const value_iterator&amp; It)</tt>:</dt>
1916 <dd> Removes a specific value from the symbol table.
1917 Returns the removed value.</dd>
1918
1919 <dt><tt>bool strip()</tt>:</dt>
1920 <dd> This method will strip the symbol table of its names leaving
1921 the type and values. </dd>
1922
1923 <dt><tt>void clear()</tt>:</dt>
1924 <dd>Empty the symbol table completely.</dd>
1925</dl>
1926
1927<h3>Iteration</h3>
1928<p>The following functions describe three types of iterators you can obtain
1929the beginning or end of the sequence for both const and non-const. It is
1930important to keep track of the different kinds of iterators. There are
1931three idioms worth pointing out:</p>
1932<table class="doc_table">
1933 <tr><th>Units</th><th>Iterator</th><th>Idiom</th></tr>
1934 <tr>
1935 <td>Planes Of name/Value maps</td><td>PI</td>
1936 <td><tt><pre>
1937for (SymbolTable::plane_const_iterator PI = ST.plane_begin(),
1938PE = ST.plane_end(); PI != PE; ++PI ) {
1939 PI-&gt;first // This is the Type* of the plane
1940 PI-&gt;second // This is the SymbolTable::ValueMap of name/Value pairs
1941 </pre></tt></td>
1942 </tr>
1943 <tr>
1944 <td>All name/Type Pairs</td><td>TI</td>
1945 <td><tt><pre>
1946for (SymbolTable::type_const_iterator TI = ST.type_begin(),
1947 TE = ST.type_end(); TI != TE; ++TI )
1948 TI-&gt;first // This is the name of the type
1949 TI-&gt;second // This is the Type* value associated with the name
1950 </pre></tt></td>
1951 </tr>
1952 <tr>
1953 <td>name/Value pairs in a plane</td><td>VI</td>
1954 <td><tt><pre>
1955for (SymbolTable::value_const_iterator VI = ST.value_begin(SomeType),
1956 VE = ST.value_end(SomeType); VI != VE; ++VI )
1957 VI-&gt;first // This is the name of the Value
1958 VI-&gt;second // This is the Value* value associated with the name
1959 </pre></tt></td>
1960 </tr>
1961</table>
1962<p>Using the recommended iterator names and idioms will help you avoid
1963making mistakes. Of particular note, make sure that whenever you use
1964value_begin(SomeType) that you always compare the resulting iterator
1965with value_end(SomeType) not value_end(SomeOtherType) or else you
1966will loop infinitely.</p>
1967
1968<dl>
1969
1970 <dt><tt>plane_iterator plane_begin()</tt>:</dt>
1971 <dd>Get an iterator that starts at the beginning of the type planes.
1972 The iterator will iterate over the Type/ValueMap pairs in the
1973 type planes. </dd>
1974
1975 <dt><tt>plane_const_iterator plane_begin() const</tt>:</dt>
1976 <dd>Get a const_iterator that starts at the beginning of the type
1977 planes. The iterator will iterate over the Type/ValueMap pairs
1978 in the type planes. </dd>
1979
1980 <dt><tt>plane_iterator plane_end()</tt>:</dt>
1981 <dd>Get an iterator at the end of the type planes. This serves as
1982 the marker for end of iteration over the type planes.</dd>
1983
1984 <dt><tt>plane_const_iterator plane_end() const</tt>:</dt>
1985 <dd>Get a const_iterator at the end of the type planes. This serves as
1986 the marker for end of iteration over the type planes.</dd>
1987
1988 <dt><tt>value_iterator value_begin(const Type *Typ)</tt>:</dt>
1989 <dd>Get an iterator that starts at the beginning of a type plane.
1990 The iterator will iterate over the name/value pairs in the type plane.
1991 Note: The type plane must already exist before using this.</dd>
1992
1993 <dt><tt>value_const_iterator value_begin(const Type *Typ) const</tt>:</dt>
1994 <dd>Get a const_iterator that starts at the beginning of a type plane.
1995 The iterator will iterate over the name/value pairs in the type plane.
1996 Note: The type plane must already exist before using this.</dd>
1997
1998 <dt><tt>value_iterator value_end(const Type *Typ)</tt>:</dt>
1999 <dd>Get an iterator to the end of a type plane. This serves as the marker
2000 for end of iteration of the type plane.
2001 Note: The type plane must already exist before using this.</dd>
2002
2003 <dt><tt>value_const_iterator value_end(const Type *Typ) const</tt>:</dt>
2004 <dd>Get a const_iterator to the end of a type plane. This serves as the
2005 marker for end of iteration of the type plane.
2006 Note: the type plane must already exist before using this.</dd>
2007
2008 <dt><tt>type_iterator type_begin()</tt>:</dt>
2009 <dd>Get an iterator to the start of the name/Type map.</dd>
2010
2011 <dt><tt>type_const_iterator type_begin() cons</tt>:</dt>
2012 <dd> Get a const_iterator to the start of the name/Type map.</dd>
2013
2014 <dt><tt>type_iterator type_end()</tt>:</dt>
2015 <dd>Get an iterator to the end of the name/Type map. This serves as the
2016 marker for end of iteration of the types.</dd>
2017
2018 <dt><tt>type_const_iterator type_end() const</tt>:</dt>
2019 <dd>Get a const-iterator to the end of the name/Type map. This serves
2020 as the marker for end of iteration of the types.</dd>
2021
2022 <dt><tt>plane_const_iterator find(const Type* Typ ) const</tt>:</dt>
2023 <dd>This method returns a plane_const_iterator for iteration over
2024 the type planes starting at a specific plane, given by \p Ty.</dd>
2025
2026 <dt><tt>plane_iterator find( const Type* Typ </tt>:</dt>
2027 <dd>This method returns a plane_iterator for iteration over the
2028 type planes starting at a specific plane, given by \p Ty.</dd>
2029
2030 <dt><tt>const ValueMap* findPlane( const Type* Typ ) cons</tt>:</dt>
2031 <dd>This method returns a ValueMap* for a specific type plane. This
2032 interface is deprecated and may go away in the future.</dd>
2033</dl>
2034</div>
2035
Chris Lattner9355b472002-09-06 02:50:58 +00002036<!-- *********************************************************************** -->
Misha Brukman13fd15c2004-01-15 00:14:41 +00002037<hr>
2038<address>
2039 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
2040 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
2041 <a href="http://validator.w3.org/check/referer"><img
2042 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
2043
2044 <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
2045 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
2046 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
2047 Last modified: $Date$
2048</address>
2049
Chris Lattner261efe92003-11-25 01:02:51 +00002050</body>
2051</html>
Reid Spencer096603a2004-05-26 08:41:35 +00002052<!-- vim: sw=2 noai
2053-->