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				2	<html><head><title>LLVM Programmer's Manual</title></head>
				3
				4	<body bgcolor=white>
				5
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	6	<table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
				7	<tr><td>  <font size=+3 color="#EEEEFF" face="Georgia,Palatino,Times,Roman"><b>LLVM Programmer's Manual</b></font></td>
				8	</tr></table>
				9
				10	<ol>
				11	<li><a href="#introduction">Introduction</a>
				12	<li><a href="#general">General Information</a>
				13	<ul>
				14	<li><a href="#stl">The C++ Standard Template Library</a>
Chris Lattner	1d43fd4	2002-09-09 05:53:21 +0000	[diff] [blame]	15	<li><a href="#isa">The <tt>isa<></tt>, <tt>cast<></tt> and
				16	<tt>dyn_cast<></tt> templates</a>
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	17	</ul>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	18	<li><a href="#common">Helpful Hints for Common Operations</a>
				19	<ul>
				20	<li><a href="#inspection">Basic Inspection and Traversal Routines</a>
				21	<ul>
				22	<li><a href="#iterate_function">Iterating over the <tt>BasicBlock</tt>s
				23	in a <tt>Function</tt></a>
				24	<li><a href="#iterate_basicblock">Iterating over the <tt>Instruction</tt>s
				25	in a <tt>BasicBlock</tt></a>
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	26	<li><a href="#iterate_institer">Iterating over the <tt>Instruction</tt>s
				27	in a <tt>Function</tt></a>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	28	<li><a href="#iterate_convert">Turning an iterator into a class
				29	pointer</a>
Chris Lattner	f1ebdc3	2002-09-06 22:09:21 +0000	[diff] [blame]	30	<li><a href="#iterate_complex">Finding call sites: a more complex
				31	example</a>
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	32	<li><a href="#iterate_chains">Iterating over def-use & use-def
				33	chains</a>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	34	</ul>
				35	<li><a href="#simplechanges">Making simple changes</a>
				36	<ul>
				37	<li>Creating and inserting new <tt>Instruction</tt>s
				38	<li>Deleting <tt>Instruction</tt>s
				39	<li>Replacing an <tt>Instruction</tt> with another <tt>Value</tt>
				40	</ul>
				41	<!--
				42	<li>Working with the Control Flow Graph
				43	<ul>
				44	<li>Accessing predecessors and successors of a <tt>BasicBlock</tt>
				45	<li>
				46	<li>
				47	</ul>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	48	<li>Useful LLVM APIs
				49	<ul>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	50	<li>The general graph API
				51	<li>The <tt>InstVisitor</tt> template
				52	<li>The DEBUG() macro
				53	<li>The <tt>Statistic</tt> template
				54	-->
				55	</ul>
				56	<!--
				57	<li>Useful related topics
				58	<ul>
				59	<li>The <tt>-time-passes</tt> option
				60	<li>How to use the LLVM Makefile system
				61	<li>How to write a regression test
				62	<li>
				63	</ul>
				64	-->
				65	</ul>
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	66	<li><a href="#coreclasses">The Core LLVM Class Hierarchy Reference</a>
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	67	<ul>
				68	<li><a href="#Value">The <tt>Value</tt> class</a>
				69	<ul>
				70	<li><a href="#User">The <tt>User</tt> class</a>
				71	<ul>
				72	<li><a href="#Instruction">The <tt>Instruction</tt> class</a>
				73	<ul>
				74	<li>
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	75	</ul>
				76	<li><a href="#GlobalValue">The <tt>GlobalValue</tt> class</a>
				77	<ul>
				78	<li><a href="#BasicBlock">The <tt>BasicBlock</tt> class</a>
				79	<li><a href="#Function">The <tt>Function</tt> class</a>
				80	<li><a href="#GlobalVariable">The <tt>GlobalVariable</tt> class</a>
				81	</ul>
				82	<li><a href="#Module">The <tt>Module</tt> class</a>
				83	<li><a href="#Constant">The <tt>Constant</tt> class</a>
				84	<ul>
				85	<li>
				86	<li>
				87	</ul>
				88	</ul>
				89	<li><a href="#Type">The <tt>Type</tt> class</a>
				90	<li><a href="#Argument">The <tt>Argument</tt> class</a>
				91	</ul>
				92	<li>The <tt>SymbolTable</tt> class
				93	<li>The <tt>ilist</tt> and <tt>iplist</tt> classes
				94	<ul>
				95	<li>Creating, inserting, moving and deleting from LLVM lists
				96	</ul>
				97	<li>Important iterator invalidation semantics to be aware of
				98	</ul>
				99
Chris Lattner	6b121f1	2002-09-10 15:20:46 +0000	[diff] [blame^]	100	<p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>,
				101	<a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a>, and
Chris Lattner	f1ebdc3	2002-09-06 22:09:21 +0000	[diff] [blame]	102	<a href="mailto:jstanley@cs.uiuc.edu">Joel Stanley</a></b><p>
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	103	</ol>
				104
				105
				106	<!-- *********************************************************************** -->
				107	<table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
				108	<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
				109	<a name="introduction">Introduction
				110	</b></font></td></tr></table><ul>
				111	<!-- *********************************************************************** -->
				112
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	113	This document is meant to highlight some of the important classes and interfaces
				114	available in the LLVM source-base. This manual is not intended to explain what
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	115	LLVM is, how it works, and what LLVM code looks like. It assumes that you know
				116	the basics of LLVM and are interested in writing transformations or otherwise
				117	analyzing or manipulating the code.<p>
				118
				119	This document should get you oriented so that you can find your way in the
				120	continuously growing source code that makes up the LLVM infrastructure. Note
				121	that this manual is not intended to serve as a replacement for reading the
				122	source code, so if you think there should be a method in one of these classes to
				123	do something, but it's not listed, check the source. Links to the <a
				124	href="/doxygen/">doxygen</a> sources are provided to make this as easy as
				125	possible.<p>
				126
				127	The first section of this document describes general information that is useful
				128	to know when working in the LLVM infrastructure, and the second describes the
				129	Core LLVM classes. In the future this manual will be extended with information
				130	describing how to use extension libraries, such as dominator information, CFG
				131	traversal routines, and useful utilities like the <tt><a
				132	href="/doxygen/InstVisitor_8h-source.html">InstVisitor</a></tt> template.<p>
				133
				134
				135	<!-- *********************************************************************** -->
				136	</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
				137	<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
				138	<a name="general">General Information
				139	</b></font></td></tr></table><ul>
				140	<!-- *********************************************************************** -->
				141
				142	This section contains general information that is useful if you are working in
				143	the LLVM source-base, but that isn't specific to any particular API.<p>
				144
				145
				146	<!-- ======================================================================= -->
				147	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				148	<tr><td> </td><td width="100%">
				149	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				150	<a name="stl">The C++ Standard Template Library</a>
				151	</b></font></td></tr></table><ul>
				152
				153	LLVM makes heavy use of the C++ Standard Template Library (STL), perhaps much
				154	more than you are used to, or have seen before. Because of this, you might want
				155	to do a little background reading in the techniques used and capabilities of the
				156	library. There are many good pages that discuss the STL, and several books on
				157	the subject that you can get, so it will not be discussed in this document.<p>
				158
				159	Here are some useful links:<p>
				160	<ol>
				161	<li><a href="http://www.dinkumware.com/htm_cpl/index.html">Dinkumware C++
				162	Library reference</a> - an excellent reference for the STL and other parts of
				163	the standard C++ library.<br>
				164
				165	<li><a href="http://www.parashift.com/c++-faq-lite/">C++ Frequently Asked
				166	Questions</a>
				167
				168	<li><a href="http://www.sgi.com/tech/stl/">SGI's STL Programmer's Guide</a> -
				169	Contains a useful <a
				170	href="http://www.sgi.com/tech/stl/stl_introduction.html">Introduction to the
				171	STL</a>.
				172
				173	<li><a href="http://www.research.att.com/~bs/C++.html">Bjarne Stroustrup's C++
				174	Page</a>
				175
				176	</ol><p>
				177
				178	You are also encouraged to take a look at the <a
				179	href="CodingStandards.html">LLVM Coding Standards</a> guide which focuses on how
				180	to write maintainable code more than where to put your curly braces.<p>
				181
				182
Chris Lattner	1d43fd4	2002-09-09 05:53:21 +0000	[diff] [blame]	183	<!-- ======================================================================= -->
				184	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				185	<tr><td> </td><td width="100%">
				186	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				187	<a name="isa">The isa<>, cast<> and dyn_cast<> templates</a>
				188	</b></font></td></tr></table><ul>
				189
Chris Lattner	979d9b7	2002-09-10 00:39:05 +0000	[diff] [blame]	190	The LLVM source-base makes extensive use of a custom form of RTTI. These
				191	templates have many similarities to the C++ <tt>dynamic_cast<></tt>
				192	operator, but they don't have some drawbacks (primarily stemming from the fact
				193	that <tt>dynamic_cast<></tt> only works on classes that have a v-table).
				194	Because they are used so often, you must know what they do and how they work.
				195	All of these templates are defined in the <a
				196	href="/doxygen/Casting_8h-source.html"><tt>Support/Casting.h</tt></a> file (note
				197	that you very rarely have to include this file directly).<p>
Chris Lattner	1d43fd4	2002-09-09 05:53:21 +0000	[diff] [blame]	198
Chris Lattner	979d9b7	2002-09-10 00:39:05 +0000	[diff] [blame]	199	<dl>
				200
				201	<dt><tt>isa<></tt>:
				202
				203	<dd>The <tt>isa<></tt> operator works exactly like the Java
				204	"<tt>instanceof</tt>" operator. It returns true or false depending on whether a
				205	reference or pointer points to an instance of the specified class. This can be
				206	very useful for constraint checking of various sorts (example below).<p>
				207
				208
				209	<dt><tt>cast<></tt>:
				210
				211	<dd>The <tt>cast<></tt> operator is a "checked cast" operation. It
				212	converts a pointer or reference from a base class to a derived cast, causing an
				213	assertion failure if it is not really an instance of the right type. This
				214	should be used in cases where you have some information that makes you believe
				215	that something is of the right type. An example of the <tt>isa<></tt> and
				216	<tt>cast<></tt> template is:<p>
				217
				218	<pre>
				219	static bool isLoopInvariant(const <a href="#Value">Value</a> V, const Loop L) {
				220	if (isa<<a href="#Constant">Constant</a>>(V) \|\| isa<<a href="#Argument">Argument</a>>(V) \|\| isa<<a href="#GlobalValue">GlobalValue</a>>(V))
				221	return true;
				222
				223	<i>// Otherwise, it must be an instruction...</i>
				224	return !L->contains(cast<<a href="#Instruction">Instruction</a>>(V)->getParent());
				225	</pre><p>
				226
				227	Note that you should <b>not</b> use an <tt>isa<></tt> test followed by a
				228	<tt>cast<></tt>, for that use the <tt>dyn_cast<></tt> operator.<p>
				229
				230
				231	<dt><tt>dyn_cast<></tt>:
				232
				233	<dd>The <tt>dyn_cast<></tt> operator is a "checking cast" operation. It
				234	checks to see if the operand is of the specified type, and if so, returns a
				235	pointer to it (this operator does not work with references). If the operand is
				236	not of the correct type, a null pointer is returned. Thus, this works very much
				237	like the <tt>dynamic_cast</tt> operator in C++, and should be used in the same
Chris Lattner	6b121f1	2002-09-10 15:20:46 +0000	[diff] [blame^]	238	circumstances. Typically, the <tt>dyn_cast<></tt> operator is used in an
				239	<tt>if</tt> statement or some other flow control statement like this:<p>
				240
				241	<pre>
				242	if (<a href="#AllocationInst">AllocationInst</a> *AI = dyn_cast<<a href="#AllocationInst">AllocationInst</a>>(Val)) {
				243	...
				244	}
				245	</pre><p>
				246
				247	This form of the <tt>if</tt> statement effectively combines together a call to
				248	<tt>isa<></tt> and a call to <tt>cast<></tt> into one statement,
				249	which is very convenient.<p>
				250
				251	Another common example is:<p>
Chris Lattner	979d9b7	2002-09-10 00:39:05 +0000	[diff] [blame]	252
				253	<pre>
				254	<i>// Loop over all of the phi nodes in a basic block</i>
				255	BasicBlock::iterator BBI = BB->begin();
				256	for (; <a href="#PhiNode">PHINode</a> PN = dyn_cast<<a href="#PHINode">PHINode</a>>(&BBI); ++BBI)
				257	cerr << *PN;
				258	</pre><p>
				259
Chris Lattner	6b121f1	2002-09-10 15:20:46 +0000	[diff] [blame^]	260	Note that the <tt>dyn_cast<></tt> operator, like C++'s
				261	<tt>dynamic_cast</tt> or Java's <tt>instanceof</tt> operator, can be abused. In
				262	particular you should not use big chained <tt>if/then/else</tt> blocks to check
				263	for lots of different variants of classes. If you find yourself wanting to do
				264	this, it is much cleaner and more efficient to use the InstVisitor class to
				265	dispatch over the instruction type directly.<p>
Chris Lattner	979d9b7	2002-09-10 00:39:05 +0000	[diff] [blame]	266
				267
Chris Lattner	6b121f1	2002-09-10 15:20:46 +0000	[diff] [blame^]	268	<dt><tt>cast_or_null<></tt>:
				269
				270	<dd>The <tt>cast_or_null<></tt> operator works just like the
				271	<tt>cast<></tt> operator, except that it allows for a null pointer as an
				272	argument (which it then propogates). This can sometimes be useful, allowing you
				273	to combine several null checks into one.<p>
				274
				275
				276	<dt><tt>dyn_cast_or_null<></tt>:
				277
				278	<dd>The <tt>dyn_cast_or_null<></tt> operator works just like the
				279	<tt>dyn_cast<></tt> operator, except that it allows for a null pointer as
				280	an argument (which it then propogates). This can sometimes be useful, allowing
				281	you to combine several null checks into one.<p>
				282
Chris Lattner	979d9b7	2002-09-10 00:39:05 +0000	[diff] [blame]	283	</dl>
Chris Lattner	1d43fd4	2002-09-09 05:53:21 +0000	[diff] [blame]	284
Chris Lattner	6b121f1	2002-09-10 15:20:46 +0000	[diff] [blame^]	285	These five templates can be used with any classes, whether they have a v-table
				286	or not. To add support for these templates, you simply need to add
				287	<tt>classof</tt> static methods to the class you are interested casting to.
				288	Describing this is currently outside the scope of this document, but there are
				289	lots of examples in the LLVM sourcebase.<p>
Chris Lattner	1d43fd4	2002-09-09 05:53:21 +0000	[diff] [blame]	290
				291
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	292
Chris Lattner	b99344f	2002-09-06 16:40:10 +0000	[diff] [blame]	293	<!-- *********************************************************************** -->
				294	</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
				295	<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
				296	<a name="common">Helpful Hints for Common Operations
				297	</b></font></td></tr></table><ul>
				298	<!-- *********************************************************************** -->
				299
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	300	This section describes how to perform some very simple transformations of LLVM
				301	code. This is meant to give examples of common idioms used, showing the
				302	practical side of LLVM transformations.<p>
				303
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	304	Because this is a "how-to" section, you should also read about the main classes
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	305	that you will be working with. The <a href="#coreclasses">Core LLVM Class
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	306	Hierarchy Reference</a> contains details and descriptions of the main classes
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	307	that you should know about.<p>
				308
				309	<!-- NOTE: this section should be heavy on example code -->
				310
				311
				312	<!-- ======================================================================= -->
				313	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				314	<tr><td> </td><td width="100%">
				315	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				316	<a name="inspection">Basic Inspection and Traversal Routines</a>
				317	</b></font></td></tr></table><ul>
				318
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	319	The LLVM compiler infrastructure have many different data structures that may be
				320	traversed. Following the example of the C++ standard template library, the
				321	techniques used to traverse these various data structures are all basically the
				322	same. For a enumerable sequence of values, the <tt>XXXbegin()</tt> function (or
				323	method) returns an iterator to the start of the sequence, the <tt>XXXend()</tt>
				324	function returns an iterator pointing to one past the last valid element of the
				325	sequence, and there is some <tt>XXXiterator</tt> data type that is common
				326	between the two operations.<p>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	327
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	328	Because the pattern for iteration is common across many different aspects of the
				329	program representation, the standard template library algorithms may be used on
				330	them, and it is easier to remember how to iterate. First we show a few common
				331	examples of the data structures that need to be traversed. Other data
				332	structures are traversed in very similar ways.<p>
				333
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	334
				335	<!-- _______________________________________________________________________ -->
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	336	</ul><h4><a name="iterate_function"><hr size=0>Iterating over the <a
				337	href="#BasicBlock"><tt>BasicBlock</tt></a>s in a <a
				338	href="#Function"><tt>Function</tt></a> </h4><ul>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	339
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	340	It's quite common to have a <tt>Function</tt> instance that you'd like
				341	to transform in some way; in particular, you'd like to manipulate its
				342	<tt>BasicBlock</tt>s. To facilitate this, you'll need to iterate over
				343	all of the <tt>BasicBlock</tt>s that constitute the <tt>Function</tt>.
				344	The following is an example that prints the name of a
				345	<tt>BasicBlock</tt> and the number of <tt>Instruction</tt>s it
				346	contains:
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	347
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	348	<pre>
				349	// func is a pointer to a Function instance
				350	for(Function::iterator i = func->begin(), e = func->end(); i != e; ++i) {
				351
				352	// print out the name of the basic block if it has one, and then the
				353	// number of instructions that it contains
				354
Joel Stanley	72ef35e	2002-09-06 23:05:12 +0000	[diff] [blame]	355	cerr <&lt "Basic block (name=" <&lt i->getName() << ") has "
				356	<&lt i->size() <&lt " instructions.\n";
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	357	}
				358	</pre>
				359
				360	Note that i can be used as if it were a pointer for the purposes of
				361	invoking member functions of the <tt>Instruction</tt> class. This is
				362	because the indirection operator is overloaded for the iterator
				363	classes. In the above code, the expression <tt>i->size()</tt> is
				364	exactly equivalent to <tt>(*i).size()</tt> just like you'd expect.
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	365
				366	<!-- _______________________________________________________________________ -->
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	367	</ul><h4><a name="iterate_basicblock"><hr size=0>Iterating over the <a
				368	href="#Instruction"><tt>Instruction</tt></a>s in a <a
				369	href="#BasicBlock"><tt>BasicBlock</tt></a> </h4><ul>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	370
Joel Stanley	aaeb1c1	2002-09-06 23:42:40 +0000	[diff] [blame]	371	Just like when dealing with <tt>BasicBlock</tt>s in
				372	<tt>Function</tt>s, it's easy to iterate over the individual
				373	instructions that make up <tt>BasicBlock</tt>s. Here's a code snippet
				374	that prints out each instruction in a <tt>BasicBlock</tt>:
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	375
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	376	<pre>
				377	// blk is a pointer to a BasicBlock instance
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	378	for(BasicBlock::iterator i = blk->begin(), e = blk->end(); i != e; ++i)
Chris Lattner	2b76306	2002-09-06 22:51:10 +0000	[diff] [blame]	379	// the next statement works since operator<<(ostream&,...)
				380	// is overloaded for Instruction&
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	381	cerr << *i << "\n";
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	382	</pre>
				383
				384	However, this isn't really the best way to print out the contents of a
				385	<tt>BasicBlock</tt>! Since the ostream operators are overloaded for
				386	virtually anything you'll care about, you could have just invoked the
Chris Lattner	2b76306	2002-09-06 22:51:10 +0000	[diff] [blame]	387	print routine on the basic block itself: <tt>cerr << *blk <<
				388	"\n";</tt>.<p>
				389
				390	Note that currently operator<< is implemented for <tt>Value*</tt>, so it
				391	will print out the contents of the pointer, instead of
				392	the pointer value you might expect. This is a deprecated interface that will
				393	be removed in the future, so it's best not to depend on it. To print out the
				394	pointer value for now, you must cast to <tt>void*</tt>.<p>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	395
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	396
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	397	<!-- _______________________________________________________________________ -->
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	398	</ul><h4><a name="iterate_institer"><hr size=0>Iterating over the <a
				399	href="#Instruction"><tt>Instruction</tt></a>s in a <a
				400	href="#Function"><tt>Function</tt></a></h4><ul>
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	401
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	402	If you're finding that you commonly iterate over a <tt>Function</tt>'s
				403	<tt>BasicBlock</tt>s and then that <tt>BasicBlock</tt>'s
				404	<tt>Instruction</tt>s, <tt>InstIterator</tt> should be used instead.
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	405	You'll need to include <a href="/doxygen/InstIterator_8h-source.html"><tt>llvm/Support/InstIterator.h</tt></a>, and then
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	406	instantiate <tt>InstIterator</tt>s explicitly in your code. Here's a
				407	small example that shows how to dump all instructions in a function to
				408	stderr (<b>Note:</b> Dereferencing an <tt>InstIterator</tt> yields an
				409	<tt>Instruction*</tt>, <i>not</i> an <tt>Instruction&amp</tt>!):
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	410
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	411	<pre>
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	412	#include "<a href="/doxygen/InstIterator_8h-source.html">llvm/Support/InstIterator.h</a>"
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	413	...
				414	// Suppose F is a ptr to a function
				415	for(inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)
				416	cerr <&lt **i <&lt "\n";
				417	</pre>
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	418
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	419	Easy, isn't it? You can also use <tt>InstIterator</tt>s to fill a
				420	worklist with its initial contents. For example, if you wanted to
				421	initialize a worklist to contain all instructions in a
				422	<tt>Function</tt> F, all you would need to do is something like:
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	423
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	424	<pre>
				425	std::set<Instruction*&gt worklist;
				426	worklist.insert(inst_begin(F), inst_end(F));
				427	</pre>
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	428
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	429	The STL set <tt>worklist</tt> would now contain all instructions in
				430	the <tt>Function</tt> pointed to by F.
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	431
				432	<!-- _______________________________________________________________________ -->
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	433	</ul><h4><a name="iterate_convert"><hr size=0>Turning an iterator into a class
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	434	pointer (and vice-versa) </h4><ul>
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	435
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	436	Sometimes, it'll be useful to grab a reference (or pointer) to a class
				437	instance when all you've got at hand is an iterator. Well, extracting
				438	a reference or a pointer from an iterator is very straightforward.
				439	Assuming that <tt>i</tt> is a <tt>BasicBlock::iterator</tt> and
				440	<tt>j</tt> is a <tt>BasicBlock::const_iterator</tt>:
				441
				442	<pre>
Chris Lattner	83b5ee0	2002-09-06 22:12:58 +0000	[diff] [blame]	443	Instruction& inst = *i; // grab reference to instruction reference
				444	Instruction* pinst = &*i; // grab pointer to instruction reference
				445	const Instruction& inst = *j;
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	446	</pre>
				447	However, the iterators you'll be working with in the LLVM framework
				448	are special: they will automatically convert to a ptr-to-instance type
				449	whenever they need to. Instead of dereferencing the iterator and then
				450	taking the address of the result, you can simply assign the iterator
				451	to the proper pointer type and you get the dereference and address-of
				452	operation as a result of the assignment (behind the scenes, this is a
				453	result of overloading casting mechanisms). Thus the last line of the
				454	last example,
				455
Chris Lattner	83b5ee0	2002-09-06 22:12:58 +0000	[diff] [blame]	456	<pre>Instruction* pinst = &*i;</pre>
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	457
				458	is semantically equivalent to
				459
				460	<pre>Instruction* pinst = i;</pre>
				461
Chris Lattner	979d9b7	2002-09-10 00:39:05 +0000	[diff] [blame]	462	<b>Caveat emptor</b>: The above syntax works <i>only</i> when you're <i>not</i>
				463	working with <tt>dyn_cast</tt>. The template definition of <tt><a
				464	href="#isa">dyn_cast</a></tt> isn't implemented to handle this yet, so you'll
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	465	still need the following in order for things to work properly:
				466
				467	<pre>
				468	BasicBlock::iterator bbi = ...;
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	469	<a href="#BranchInst">BranchInst</a>* b = <a href="#isa">dyn_cast</a><<a href="#BranchInst">BranchInst</a>>(&*bbi);
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	470	</pre>
				471
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	472	It's also possible to turn a class pointer into the corresponding
				473	iterator. Usually, this conversion is quite inexpensive. The
				474	following code snippet illustrates use of the conversion constructors
				475	provided by LLVM iterators. By using these, you can explicitly grab
				476	the iterator of something without actually obtaining it via iteration
				477	over some structure:
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	478
				479	<pre>
				480	void printNextInstruction(Instruction* inst) {
				481	BasicBlock::iterator it(inst);
				482	++it; // after this line, it refers to the instruction after *inst.
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	483	if(it != inst->getParent()->end()) cerr << *it << "\n";
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	484	}
				485	</pre>
Joel Stanley	aaeb1c1	2002-09-06 23:42:40 +0000	[diff] [blame]	486	Of course, this example is strictly pedagogical, because it'd be much
				487	better to explicitly grab the next instruction directly from inst.
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	488
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	489
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	490	<!--_______________________________________________________________________-->
				491	</ul><h4><a name="iterate_complex"><hr size=0>Finding call sites: a slightly
				492	more complex example </h4><ul>
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	493
				494	Say that you're writing a FunctionPass and would like to count all the
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	495	locations in the entire module (that is, across every
Joel Stanley	d8aabb2	2002-09-09 16:29:58 +0000	[diff] [blame]	496	<tt>Function</tt>) where a certain function (i.e. some
				497	<tt>Function</tt>*) already in scope. As you'll learn later, you may
				498	want to use an <tt>InstVisitor</tt> to accomplish this in a much more
				499	straightforward manner, but this example will allow us to explore how
				500	you'd do it if you didn't have <tt>InstVisitor</tt> around. In
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	501	pseudocode, this is what we want to do:
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	502
				503	<pre>
				504	initialize callCounter to zero
				505	for each Function f in the Module
				506	for each BasicBlock b in f
				507	for each Instruction i in b
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	508	if(i is a CallInst and calls the given function)
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	509	increment callCounter
				510	</pre>
				511
				512	And the actual code is (remember, since we're writing a
Joel Stanley	d8aabb2	2002-09-09 16:29:58 +0000	[diff] [blame]	513	<tt>FunctionPass</tt>, our <tt>FunctionPass</tt>-derived class simply
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	514	has to override the <tt>runOnFunction</tt> method...):
				515
				516	<pre>
Joel Stanley	d8aabb2	2002-09-09 16:29:58 +0000	[diff] [blame]	517	Function* targetFunc = ...;
				518
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	519	class OurFunctionPass : public FunctionPass {
				520	public:
Joel Stanley	d8aabb2	2002-09-09 16:29:58 +0000	[diff] [blame]	521	OurFunctionPass(): callCounter(0) { }
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	522
Chris Lattner	caa5d13	2002-09-09 19:58:18 +0000	[diff] [blame]	523	virtual runOnFunction(Function& F) {
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	524	for(Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
				525	for(BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {
Chris Lattner	979d9b7	2002-09-10 00:39:05 +0000	[diff] [blame]	526	if (<a href="#CallInst">CallInst</a>* callInst = <a href="#isa">dyn_cast</a><<a href="#CallInst">CallInst</a>>(&*inst)) {
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	527	// we know we've encountered a call instruction, so we
				528	// need to determine if it's a call to the
				529	// function pointed to by m_func or not.
				530
Joel Stanley	d8aabb2	2002-09-09 16:29:58 +0000	[diff] [blame]	531	if(callInst->getCalledFunction() == targetFunc)
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	532	++callCounter;
				533	}
				534	}
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	535	}
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	536
				537	private:
Joel Stanley	d8aabb2	2002-09-09 16:29:58 +0000	[diff] [blame]	538	unsigned callCounter;
Joel Stanley	e7be650	2002-09-09 15:50:33 +0000	[diff] [blame]	539	};
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	540	</pre>
				541
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	542	<!--_______________________________________________________________________-->
				543	</ul><h4><a name="iterate_chains"><hr size=0>Iterating over def-use &
				544	use-def chains</h4><ul>
				545
Chris Lattner	1a3105b	2002-09-09 05:49:39 +0000	[diff] [blame]	546	<!--
				547	def-use chains ("finding all users of"): Value::use_begin/use_end
				548	use-def chains ("finding all values used"): User::op_begin/op_end [op=operand]
				549	-->
				550
Chris Lattner	ae7f759	2002-09-06 18:31:18 +0000	[diff] [blame]	551	<!-- ======================================================================= -->
				552	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				553	<tr><td> </td><td width="100%">
				554	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				555	<a name="simplechanges">Making simple changes</a>
				556	</b></font></td></tr></table><ul>
				557
				558	<!-- Value::replaceAllUsesWith
				559	User::replaceUsesOfWith
				560	Point out: include/llvm/Transforms/Utils/
				561	especially BasicBlockUtils.h with:
				562	ReplaceInstWithValue, ReplaceInstWithInst
				563
				564	-->
Chris Lattner	b99344f	2002-09-06 16:40:10 +0000	[diff] [blame]	565
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	566
				567	<!-- *********************************************************************** -->
				568	</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
				569	<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	570	<a name="coreclasses">The Core LLVM Class Hierarchy Reference
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	571	</b></font></td></tr></table><ul>
				572	<!-- *********************************************************************** -->
				573
				574	The Core LLVM classes are the primary means of representing the program being
				575	inspected or transformed. The core LLVM classes are defined in header files in
				576	the <tt>include/llvm/</tt> directory, and implemented in the <tt>lib/VMCore</tt>
				577	directory.<p>
				578
				579
				580	<!-- ======================================================================= -->
				581	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				582	<tr><td> </td><td width="100%">
				583	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				584	<a name="Value">The <tt>Value</tt> class</a>
				585	</b></font></td></tr></table><ul>
				586
				587	<tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt></b><br>
				588	doxygen info: <a href="/doxygen/classValue.html">Value Class</a><p>
				589
				590
				591	The <tt>Value</tt> class is the most important class in LLVM Source base. It
				592	represents a typed value that may be used (among other things) as an operand to
				593	an instruction. There are many different types of <tt>Value</tt>s, such as <a
				594	href="#Constant"><tt>Constant</tt></a>s, <a
				595	href="#Argument"><tt>Argument</tt></a>s, and even <a
				596	href="#Instruction"><tt>Instruction</tt></a>s and <a
				597	href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.<p>
				598
				599	A particular <tt>Value</tt> may be used many times in the LLVM representation
				600	for a program. For example, an incoming argument to a function (represented
				601	with an instance of the <a href="#Argument">Argument</a> class) is "used" by
				602	every instruction in the function that references the argument. To keep track
				603	of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
				604	href="#User"><tt>User</tt></a>s that is using it (the <a
				605	href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
				606	graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
Joel Stanley	9b96c44	2002-09-06 21:55:13 +0000	[diff] [blame]	607	def-use information in the program, and is accessible through the <tt>use_</tt>*
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	608	methods, shown below.<p>
				609
				610	Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed, and
				611	this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
				612	method. <a name="#nameWarning">In addition, all LLVM values can be named. The
				613	"name" of the <tt>Value</tt> is symbolic string printed in the LLVM code:<p>
				614
				615	<pre>
				616	%<b>foo</b> = add int 1, 2
				617	</pre>
				618
				619	The name of this instruction is "foo". <b>NOTE</b> that the name of any value
				620	may be missing (an empty string), so names should <b>ONLY</b> be used for
				621	debugging (making the source code easier to read, debugging printouts), they
				622	should not be used to keep track of values or map between them. For this
				623	purpose, use a <tt>std::map</tt> of pointers to the <tt>Value</tt> itself
				624	instead.<p>
				625
				626	One important aspect of LLVM is that there is no distinction between an SSA
				627	variable and the operation that produces it. Because of this, any reference to
				628	the value produced by an instruction (or the value available as an incoming
				629	argument, for example) is represented as a direct pointer to the class that
				630	represents this value. Although this may take some getting used to, it
				631	simplifies the representation and makes it easier to manipulate.<p>
				632
				633
				634	<!-- _______________________________________________________________________ -->
				635	</ul><h4><a name="m_Value"><hr size=0>Important Public Members of
				636	the <tt>Value</tt> class</h4><ul>
				637
				638	<li><tt>Value::use_iterator</tt> - Typedef for iterator over the use-list<br>
				639	<tt>Value::use_const_iterator</tt>
				640	- Typedef for const_iterator over the use-list<br>
				641	<tt>unsigned use_size()</tt> - Returns the number of users of the value.<br>
				642	<tt>bool use_empty()</tt> - Returns true if there are no users.<br>
				643	<tt>use_iterator use_begin()</tt>
				644	- Get an iterator to the start of the use-list.<br>
				645	<tt>use_iterator use_end()</tt>
				646	- Get an iterator to the end of the use-list.<br>
				647	<tt><a href="#User">User</a> *use_back()</tt>
				648	- Returns the last element in the list.<p>
				649
				650	These methods are the interface to access the def-use information in LLVM. As with all other iterators in LLVM, the naming conventions follow the conventions defined by the <a href="#stl">STL</a>.<p>
				651
				652	<li><tt><a href="#Type">Type</a> *getType() const</tt><p>
				653	This method returns the Type of the Value.
				654
				655	<li><tt>bool hasName() const</tt><br>
				656	<tt>std::string getName() const</tt><br>
				657	<tt>void setName(const std::string &Name)</tt><p>
				658
				659	This family of methods is used to access and assign a name to a <tt>Value</tt>,
				660	be aware of the <a href="#nameWarning">precaution above</a>.<p>
				661
				662
				663	<li><tt>void replaceAllUsesWith(Value *V)</tt><p>
				664
				665	This method traverses the use list of a <tt>Value</tt> changing all <a
				666	href="#User"><tt>User</tt>'s</a> of the current value to refer to "<tt>V</tt>"
				667	instead. For example, if you detect that an instruction always produces a
				668	constant value (for example through constant folding), you can replace all uses
				669	of the instruction with the constant like this:<p>
				670
				671	<pre>
				672	Inst->replaceAllUsesWith(ConstVal);
				673	</pre><p>
				674
				675
				676
				677	<!-- ======================================================================= -->
				678	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				679	<tr><td> </td><td width="100%">
				680	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				681	<a name="User">The <tt>User</tt> class</a>
				682	</b></font></td></tr></table><ul>
				683
				684	<tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt></b><br>
				685	doxygen info: <a href="/doxygen/classUser.html">User Class</a><br>
				686	Superclass: <a href="#Value"><tt>Value</tt></a><p>
				687
				688
				689	The <tt>User</tt> class is the common base class of all LLVM nodes that may
				690	refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
				691	that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
				692	referring to. The <tt>User</tt> class itself is a subclass of
				693	<tt>Value</tt>.<p>
				694
				695	The operands of a <tt>User</tt> point directly to the LLVM <a
				696	href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
				697	Single Assignment (SSA) form, there can only be one definition referred to,
				698	allowing this direct connection. This connection provides the use-def
				699	information in LLVM.<p>
				700
				701	<!-- _______________________________________________________________________ -->
				702	</ul><h4><a name="m_User"><hr size=0>Important Public Members of
				703	the <tt>User</tt> class</h4><ul>
				704
				705	The <tt>User</tt> class exposes the operand list in two ways: through an index
				706	access interface and through an iterator based interface.<p>
				707
				708	<li><tt>Value *getOperand(unsigned i)</tt><br>
				709	<tt>unsigned getNumOperands()</tt><p>
				710
				711	These two methods expose the operands of the <tt>User</tt> in a convenient form
				712	for direct access.<p>
				713
				714	<li><tt>User::op_iterator</tt> - Typedef for iterator over the operand list<br>
				715	<tt>User::op_const_iterator</tt>
				716	<tt>use_iterator op_begin()</tt>
				717	- Get an iterator to the start of the operand list.<br>
				718	<tt>use_iterator op_end()</tt>
				719	- Get an iterator to the end of the operand list.<p>
				720
				721	Together, these methods make up the iterator based interface to the operands of
				722	a <tt>User</tt>.<p>
				723
				724
				725
				726	<!-- ======================================================================= -->
				727	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				728	<tr><td> </td><td width="100%">
				729	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				730	<a name="Instruction">The <tt>Instruction</tt> class</a>
				731	</b></font></td></tr></table><ul>
				732
				733	<tt>#include "<a
				734	href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt></b><br>
				735	doxygen info: <a href="/doxygen/classInstruction.html">Instruction Class</a><br>
				736	Superclasses: <a href="#User"><tt>User</tt></a>, <a
				737	href="#Value"><tt>Value</tt></a><p>
				738
				739	The <tt>Instruction</tt> class is the common base class for all LLVM
				740	instructions. It provides only a few methods, but is a very commonly used
				741	class. The primary data tracked by the <tt>Instruction</tt> class itself is the
				742	opcode (instruction type) and the parent <a
				743	href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
				744	into. To represent a specific type of instruction, one of many subclasses of
				745	<tt>Instruction</tt> are used.<p>
				746
				747	Because the <tt>Instruction</tt> class subclasses the <a
				748	href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
				749	way as for other <a href="#User"><tt>User</tt></a>s (with the
				750	<tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
				751	<tt>op_begin()</tt>/<tt>op_end()</tt> methods).<p>
				752
				753
				754	<!-- _______________________________________________________________________ -->
				755	</ul><h4><a name="m_Instruction"><hr size=0>Important Public Members of
				756	the <tt>Instruction</tt> class</h4><ul>
				757
				758	<li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt><p>
				759
				760	Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that this
				761	<tt>Instruction</tt> is embedded into.<p>
				762
				763	<li><tt>bool hasSideEffects()</tt><p>
				764
				765	Returns true if the instruction has side effects, i.e. it is a <tt>call</tt>,
				766	<tt>free</tt>, <tt>invoke</tt>, or <tt>store</tt>.<p>
				767
				768	<li><tt>unsigned getOpcode()</tt><p>
				769
				770	Returns the opcode for the <tt>Instruction</tt>.<p>
				771
				772	<!--
				773
				774	\subsection{Subclasses of Instruction :}
				775	\begin{itemize}
				776	<li>BinaryOperator : This subclass of Instruction defines a general interface to the all the instructions involvong binary operators in LLVM.
				777	\begin{itemize}
				778	<li><tt>bool swapOperands()</tt>: Exchange the two operands to this instruction. If the instruction cannot be reversed (i.e. if it's a Div), it returns true.
				779	\end{itemize}
				780	<li>TerminatorInst : This subclass of Instructions defines an interface for all instructions that can terminate a BasicBlock.
				781	\begin{itemize}
				782	<li> <tt>unsigned getNumSuccessors()</tt>: Returns the number of successors for this terminator instruction.
				783	<li><tt>BasicBlock *getSuccessor(unsigned i)</tt>: As the name suggests returns the ith successor BasicBlock.
				784	<li><tt>void setSuccessor(unsigned i, BasicBlock *B)</tt>: sets BasicBlock B as the ith succesor to this terminator instruction.
				785	\end{itemize}
				786
				787	<li>PHINode : This represents the PHI instructions in the SSA form.
				788	\begin{itemize}
				789	<li><tt> unsigned getNumIncomingValues()</tt>: Returns the number of incoming edges to this PHI node.
				790	<li><tt> Value *getIncomingValue(unsigned i)</tt>: Returns the ith incoming Value.
				791	<li><tt>void setIncomingValue(unsigned i, Value *V)</tt>: Sets the ith incoming Value as V
				792	<li><tt>BasicBlock *getIncomingBlock(unsigned i)</tt>: Returns the Basic Block corresponding to the ith incoming Value.
				793	<li><tt> void addIncoming(Value D, BasicBlock BB)</tt>:
				794	Add an incoming value to the end of the PHI list
				795	<li><tt> int getBasicBlockIndex(const BasicBlock *BB) const</tt>:
				796	Returns the first index of the specified basic block in the value list for this PHI. Returns -1 if no instance.
				797	\end{itemize}
				798	<li>CastInst : In LLVM all casts have to be done through explicit cast instructions. CastInst defines the interface to the cast instructions.
				799	<li>CallInst : This defines an interface to the call instruction in LLVM. ARguments to the function are nothing but operands of the instruction.
				800	\begin{itemize}
				801	<li>: <tt>Function *getCalledFunction()</tt>: Returns a handle to the function that is being called by this Function.
				802	\end{itemize}
				803	<li>LoadInst, StoreInst, GetElemPtrInst : These subclasses represent load, store and getelementptr instructions in LLVM.
				804	\begin{itemize}
				805	<li><tt>Value * getPointerOperand ()</tt>: Returns the Pointer Operand which is typically the 0th operand.
				806	\end{itemize}
				807	<li>BranchInst : This is a subclass of TerminatorInst and defines the interface for conditional and unconditional branches in LLVM.
				808	\begin{itemize}
				809	<li><tt>bool isConditional()</tt>: Returns true if the branch is a conditional branch else returns false
				810	<li> <tt>Value *getCondition()</tt>: Returns the condition if it is a conditional branch else returns null.
				811	<li> <tt>void setUnconditionalDest(BasicBlock *Dest)</tt>: Changes the current branch to an unconditional one targetting the specified block.
				812	\end{itemize}
				813
				814	\end{itemize}
				815
				816	-->
				817
				818
				819	<!-- ======================================================================= -->
				820	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				821	<tr><td> </td><td width="100%">
				822	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				823	<a name="BasicBlock">The <tt>BasicBlock</tt> class</a>
				824	</b></font></td></tr></table><ul>
				825
				826	<tt>#include "<a
				827	href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt></b><br>
				828	doxygen info: <a href="/doxygen/classBasicBlock.html">BasicBlock Class</a><br>
				829	Superclass: <a href="#Value"><tt>Value</tt></a><p>
				830
				831
				832	This class represents a single entry multiple exit section of the code, commonly
				833	known as a basic block by the compiler community. The <tt>BasicBlock</tt> class
				834	maintains a list of <a href="#Instruction"><tt>Instruction</tt></a>s, which form
				835	the body of the block. Matching the language definition, the last element of
				836	this list of instructions is always a terminator instruction (a subclass of the
				837	<a href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).<p>
				838
				839	In addition to tracking the list of instructions that make up the block, the
				840	<tt>BasicBlock</tt> class also keeps track of the <a
				841	href="#Function"><tt>Function</tt></a> that it is embedded into.<p>
				842
				843	Note that <tt>BasicBlock</tt>s themselves are <a
				844	href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
				845	like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
				846	<tt>label</tt>.<p>
				847
				848
				849	<!-- _______________________________________________________________________ -->
				850	</ul><h4><a name="m_BasicBlock"><hr size=0>Important Public Members of
				851	the <tt>BasicBlock</tt> class</h4><ul>
				852
				853	<li><tt>BasicBlock(const std::string &Name = "", <a
				854	href="#Function">Function</a> *Parent = 0)</tt><p>
				855
				856	The <tt>BasicBlock</tt> constructor is used to create new basic blocks for
				857	insertion into a function. The constructor simply takes a name for the new
				858	block, and optionally a <a href="#Function"><tt>Function</tt></a> to insert it
				859	into. If the <tt>Parent</tt> parameter is specified, the new
				860	<tt>BasicBlock</tt> is automatically inserted at the end of the specified <a
				861	href="#Function"><tt>Function</tt></a>, if not specified, the BasicBlock must be
				862	manually inserted into the <a href="#Function"><tt>Function</tt></a>.<p>
				863
				864	<li><tt>BasicBlock::iterator</tt> - Typedef for instruction list iterator<br>
				865	<tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
				866	<tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
				867	<tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
				868
				869	These methods and typedefs are forwarding functions that have the same semantics
				870	as the standard library methods of the same names. These methods expose the
				871	underlying instruction list of a basic block in a way that is easy to
				872	manipulate. To get the full complement of container operations (including
				873	operations to update the list), you must use the <tt>getInstList()</tt>
				874	method.<p>
				875
				876	<li><tt>BasicBlock::InstListType &getInstList()</tt><p>
				877
				878	This method is used to get access to the underlying container that actually
				879	holds the Instructions. This method must be used when there isn't a forwarding
				880	function in the <tt>BasicBlock</tt> class for the operation that you would like
				881	to perform. Because there are no forwarding functions for "updating"
				882	operations, you need to use this if you want to update the contents of a
				883	<tt>BasicBlock</tt>.<p>
				884
				885	<li><tt><A href="#Function">Function</a> *getParent()</tt><p>
				886
				887	Returns a pointer to <a href="#Function"><tt>Function</tt></a> the block is
				888	embedded into, or a null pointer if it is homeless.<p>
				889
				890	<li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt><p>
				891
				892	Returns a pointer to the terminator instruction that appears at the end of the
				893	<tt>BasicBlock</tt>. If there is no terminator instruction, or if the last
				894	instruction in the block is not a terminator, then a null pointer is
				895	returned.<p>
				896
				897
				898	<!-- ======================================================================= -->
				899	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				900	<tr><td> </td><td width="100%">
				901	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				902	<a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
				903	</b></font></td></tr></table><ul>
				904
				905	<tt>#include "<a
				906	href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt></b><br>
				907	doxygen info: <a href="/doxygen/classGlobalValue.html">GlobalValue Class</a><br>
				908	Superclasses: <a href="#User"><tt>User</tt></a>, <a
				909	href="#Value"><tt>Value</tt></a><p>
				910
				911	Global values (<A href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
				912	href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
				913	visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
				914	Because they are visible at global scope, they are also subject to linking with
				915	other globals defined in different translation units. To control the linking
				916	process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
				917	<tt>GlobalValue</tt>s know whether they have internal or external linkage.<p>
				918
				919	If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
				920	<tt>static</tt> in C), it is not visible to code outside the current translation
				921	unit, and does not participate in linking. If it has external linkage, it is
				922	visible to external code, and does participate in linking. In addition to
				923	linkage information, <tt>GlobalValue</tt>s keep track of which <a
				924	href="#Module"><tt>Module</tt></a> they are currently part of.<p>
				925
				926	Because <tt>GlobalValue</tt>s are memory objects, they are always referred to by
				927	their address. As such, the <a href="#Type"><tt>Type</tt></a> of a global is
				928	always a pointer to its contents. This is explained in the LLVM Language
				929	Reference Manual.<p>
				930
				931
				932	<!-- _______________________________________________________________________ -->
				933	</ul><h4><a name="m_GlobalValue"><hr size=0>Important Public Members of
				934	the <tt>GlobalValue</tt> class</h4><ul>
				935
				936	<li><tt>bool hasInternalLinkage() const</tt><br>
				937	<tt>bool hasExternalLinkage() const</tt><br>
				938	<tt>void setInternalLinkage(bool HasInternalLinkage)</tt><p>
				939
				940	These methods manipulate the linkage characteristics of the
				941	<tt>GlobalValue</tt>.<p>
				942
				943	<li><tt><a href="#Module">Module</a> *getParent()</tt><p>
				944
				945	This returns the <a href="#Module"><tt>Module</tt></a> that the GlobalValue is
				946	currently embedded into.<p>
				947
				948
				949
				950	<!-- ======================================================================= -->
				951	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				952	<tr><td> </td><td width="100%">
				953	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				954	<a name="Function">The <tt>Function</tt> class</a>
				955	</b></font></td></tr></table><ul>
				956
				957	<tt>#include "<a
				958	href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt></b><br>
				959	doxygen info: <a href="/doxygen/classFunction.html">Function Class</a><br>
				960	Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
				961	href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
				962
				963	The <tt>Function</tt> class represents a single procedure in LLVM. It is
				964	actually one of the more complex classes in the LLVM heirarchy because it must
				965	keep track of a large amount of data. The <tt>Function</tt> class keeps track
				966	of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
				967	href="#Argument"><tt>Argument</tt></a>s, and a <a
				968	href="#SymbolTable"><tt>SymbolTable</tt></a>.<p>
				969
				970	The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most commonly
				971	used part of <tt>Function</tt> objects. The list imposes an implicit ordering
				972	of the blocks in the function, which indicate how the code will be layed out by
				973	the backend. Additionally, the first <a
				974	href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
				975	<tt>Function</tt>. It is not legal in LLVM explicitly branch to this initial
				976	block. There are no implicit exit nodes, and in fact there may be multiple exit
				977	nodes from a single <tt>Function</tt>. If the <a
				978	href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
				979	the <tt>Function</tt> is actually a function declaration: the actual body of the
				980	function hasn't been linked in yet.<p>
				981
				982	In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
				983	<tt>Function</tt> class also keeps track of the list of formal <a
				984	href="#Argument"><tt>Argument</tt></a>s that the function receives. This
				985	container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
				986	nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
				987	the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.<p>
				988
				989	The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used LLVM
				990	feature that is only used when you have to look up a value by name. Aside from
				991	that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used internally to
				992	make sure that there are not conflicts between the names of <a
				993	href="#Instruction"><tt>Instruction</tt></a>s, <a
				994	href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
				995	href="#Argument"><tt>Argument</tt></a>s in the function body.<p>
				996
				997
				998	<!-- _______________________________________________________________________ -->
				999	</ul><h4><a name="m_Function"><hr size=0>Important Public Members of
				1000	the <tt>Function</tt> class</h4><ul>
				1001
				1002	<li><tt>Function(const <a href="#FunctionType">FunctionType</a> *Ty, bool isInternal, const std::string &N = "")</tt><p>
				1003
				1004	Constructor used when you need to create new <tt>Function</tt>s to add the the
				1005	program. The constructor must specify the type of the function to create and
				1006	whether or not it should start out with internal or external linkage.<p>
				1007
				1008	<li><tt>bool isExternal()</tt><p>
				1009
				1010	Return whether or not the <tt>Function</tt> has a body defined. If the function
				1011	is "external", it does not have a body, and thus must be resolved by linking
				1012	with a function defined in a different translation unit.<p>
				1013
				1014
				1015	<li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
				1016	<tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
				1017	<tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
				1018	<tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
				1019
				1020	These are forwarding methods that make it easy to access the contents of a
				1021	<tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
				1022	list.<p>
				1023
				1024	<li><tt>Function::BasicBlockListType &getBasicBlockList()</tt><p>
				1025
				1026	Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This is
				1027	neccesary to use when you need to update the list or perform a complex action
				1028	that doesn't have a forwarding method.<p>
				1029
				1030
				1031	<li><tt>Function::aiterator</tt> - Typedef for the argument list iterator<br>
				1032	<tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
				1033	<tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
				1034	<tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt><p>
				1035
				1036	These are forwarding methods that make it easy to access the contents of a
				1037	<tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a> list.<p>
				1038
				1039	<li><tt>Function::ArgumentListType &getArgumentList()</tt><p>
				1040
				1041	Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This is
				1042	neccesary to use when you need to update the list or perform a complex action
				1043	that doesn't have a forwarding method.<p>
				1044
				1045
				1046
				1047	<li><tt><a href="#BasicBlock">BasicBlock</a> &getEntryNode()</tt><p>
				1048
				1049	Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
				1050	function. Because the entry block for the function is always the first block,
				1051	this returns the first block of the <tt>Function</tt>.<p>
				1052
				1053	<li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
				1054	<tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt><p>
				1055
				1056	This traverses the <a href="#Type"><tt>Type</tt></a> of the <tt>Function</tt>
				1057	and returns the return type of the function, or the <a
				1058	href="#FunctionType"><tt>FunctionType</tt></a> of the actual function.<p>
				1059
				1060
				1061	<li><tt>bool hasSymbolTable() const</tt><p>
				1062
				1063	Return true if the <tt>Function</tt> has a symbol table allocated to it and if
				1064	there is at least one entry in it.<p>
				1065
				1066	<li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
				1067
				1068	Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
				1069	<tt>Function</tt> or a null pointer if one has not been allocated (because there
				1070	are no named values in the function).<p>
				1071
				1072	<li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
				1073
				1074	Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
				1075	<tt>Function</tt> or allocate a new <a
				1076	href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
				1077	should only be used when adding elements to the <a
				1078	href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
				1079	not left laying around.<p>
				1080
				1081
				1082
				1083	<!-- ======================================================================= -->
				1084	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				1085	<tr><td> </td><td width="100%">
				1086	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				1087	<a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
				1088	</b></font></td></tr></table><ul>
				1089
				1090	<tt>#include "<a
				1091	href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt></b><br>
				1092	doxygen info: <a href="/doxygen/classGlobalVariable.html">GlobalVariable Class</a><br>
				1093	Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
				1094	href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
				1095
Chris Lattner	0377de4	2002-09-06 14:50:55 +0000	[diff] [blame]	1096	Global variables are represented with the (suprise suprise)
				1097	<tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are
				1098	also subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such
				1099	are always referenced by their address (global values must live in memory, so
				1100	their "name" refers to their address). Global variables may have an initial
				1101	value (which must be a <a href="#Constant"><tt>Constant</tt></a>), and if they
				1102	have an initializer, they may be marked as "constant" themselves (indicating
				1103	that their contents never change at runtime).<p>
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	1104
				1105
				1106	<!-- _______________________________________________________________________ -->
Chris Lattner	0377de4	2002-09-06 14:50:55 +0000	[diff] [blame]	1107	</ul><h4><a name="m_GlobalVariable"><hr size=0>Important Public Members of the
				1108	<tt>GlobalVariable</tt> class</h4><ul>
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	1109
				1110	<li><tt>GlobalVariable(const <a href="#Type">Type</a> *Ty, bool isConstant, bool
				1111	isInternal, <a href="#Constant">Constant</a> *Initializer = 0, const std::string
				1112	&Name = "")</tt><p>
				1113
Chris Lattner	0377de4	2002-09-06 14:50:55 +0000	[diff] [blame]	1114	Create a new global variable of the specified type. If <tt>isConstant</tt> is
				1115	true then the global variable will be marked as unchanging for the program, and
				1116	if <tt>isInternal</tt> is true the resultant global variable will have internal
				1117	linkage. Optionally an initializer and name may be specified for the global variable as well.<p>
				1118
				1119
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	1120	<li><tt>bool isConstant() const</tt><p>
				1121
				1122	Returns true if this is a global variable is known not to be modified at
				1123	runtime.<p>
				1124
Chris Lattner	0377de4	2002-09-06 14:50:55 +0000	[diff] [blame]	1125
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	1126	<li><tt>bool hasInitializer()</tt><p>
				1127
				1128	Returns true if this <tt>GlobalVariable</tt> has an intializer.<p>
				1129
Chris Lattner	0377de4	2002-09-06 14:50:55 +0000	[diff] [blame]	1130
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	1131	<li><tt><a href="#Constant">Constant</a> *getInitializer()</tt><p>
				1132
Chris Lattner	0377de4	2002-09-06 14:50:55 +0000	[diff] [blame]	1133	Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal to call
				1134	this method if there is no initializer.<p>
				1135
				1136
				1137	<!-- ======================================================================= -->
				1138	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				1139	<tr><td> </td><td width="100%">
				1140	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				1141	<a name="Module">The <tt>Module</tt> class</a>
				1142	</b></font></td></tr></table><ul>
				1143
				1144	<tt>#include "<a
				1145	href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt></b><br>
				1146	doxygen info: <a href="/doxygen/classModule.html">Module Class</a><p>
				1147
				1148	The <tt>Module</tt> class represents the top level structure present in LLVM
				1149	programs. An LLVM module is effectively either a translation unit of the
				1150	original program or a combination of several translation units merged by the
				1151	linker. The <tt>Module</tt> class keeps track of a list of <a
				1152	href="#Function"><tt>Function</tt></a>s, a list of <a
				1153	href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
				1154	href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
				1155	helpful member functions that try to make common operations easy.<p>
				1156
				1157
				1158	<!-- _______________________________________________________________________ -->
				1159	</ul><h4><a name="m_Module"><hr size=0>Important Public Members of the
				1160	<tt>Module</tt> class</h4><ul>
				1161
				1162	<li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
				1163	<tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
				1164	<tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
				1165	<tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
				1166
				1167	These are forwarding methods that make it easy to access the contents of a
				1168	<tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
				1169	list.<p>
				1170
				1171	<li><tt>Module::FunctionListType &getFunctionList()</tt><p>
				1172
				1173	Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
				1174	neccesary to use when you need to update the list or perform a complex action
				1175	that doesn't have a forwarding method.<p>
				1176
				1177	<!-- Global Variable -->
				1178	<hr size=0>
				1179
				1180	<li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
				1181	<tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
				1182	<tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
				1183	<tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt><p>
				1184
				1185	These are forwarding methods that make it easy to access the contents of a
				1186	<tt>Module</tt> object's <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>
				1187	list.<p>
				1188
				1189	<li><tt>Module::GlobalListType &getGlobalList()</tt><p>
				1190
				1191	Returns the list of <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s.
				1192	This is neccesary to use when you need to update the list or perform a complex
				1193	action that doesn't have a forwarding method.<p>
				1194
				1195
				1196	<!-- Symbol table stuff -->
				1197	<hr size=0>
				1198
				1199	<li><tt>bool hasSymbolTable() const</tt><p>
				1200
				1201	Return true if the <tt>Module</tt> has a symbol table allocated to it and if
				1202	there is at least one entry in it.<p>
				1203
				1204	<li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
				1205
				1206	Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
				1207	<tt>Module</tt> or a null pointer if one has not been allocated (because there
				1208	are no named values in the function).<p>
				1209
				1210	<li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
				1211
				1212	Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
				1213	<tt>Module</tt> or allocate a new <a
				1214	href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
				1215	should only be used when adding elements to the <a
				1216	href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
				1217	not left laying around.<p>
				1218
				1219
				1220	<!-- Convenience methods -->
				1221	<hr size=0>
				1222
				1223	<li><tt><a href="#Function">Function</a> getFunction(const std::string &Name, const <a href="#FunctionType">FunctionType</a> Ty)</tt><p>
				1224
				1225	Look up the specified function in the <tt>Module</tt> <a
				1226	href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
				1227	<tt>null</tt>.<p>
				1228
				1229
				1230	<li><tt><a href="#Function">Function</a> *getOrInsertFunction(const std::string
				1231	&Name, const <a href="#FunctionType">FunctionType</a> *T)</tt><p>
				1232
				1233	Look up the specified function in the <tt>Module</tt> <a
				1234	href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, add an
				1235	external declaration for the function and return it.<p>
				1236
				1237
				1238	<li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt><p>
				1239
				1240	If there is at least one entry in the <a
				1241	href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
				1242	href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
				1243	string.<p>
				1244
				1245
				1246	<li><tt>bool addTypeName(const std::string &Name, const <a href="#Type">Type</a>
				1247	*Ty)</tt><p>
				1248
				1249	Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a> mapping
				1250	<tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this name, true
				1251	is returned and the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is not
				1252	modified.<p>
				1253
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	1254
				1255	<!-- ======================================================================= -->
				1256	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				1257	<tr><td> </td><td width="100%">
				1258	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				1259	<a name="Constant">The <tt>Constant</tt> class and subclasses</a>
				1260	</b></font></td></tr></table><ul>
				1261
				1262	Constant represents a base class for different types of constants. It is
				1263	subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
				1264	ConstantArray etc for representing the various types of Constants.<p>
				1265
				1266
				1267	<!-- _______________________________________________________________________ -->
				1268	</ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
				1269
				1270	<li><tt>bool isConstantExpr()</tt>: Returns true if it is a ConstantExpr
				1271
				1272
				1273
				1274
				1275	\subsection{Important Subclasses of Constant}
				1276	\begin{itemize}
				1277	<li>ConstantSInt : This subclass of Constant represents a signed integer constant.
				1278	\begin{itemize}
				1279	<li><tt>int64_t getValue () const</tt>: Returns the underlying value of this constant.
				1280	\end{itemize}
				1281	<li>ConstantUInt : This class represents an unsigned integer.
				1282	\begin{itemize}
				1283	<li><tt>uint64_t getValue () const</tt>: Returns the underlying value of this constant.
				1284	\end{itemize}
				1285	<li>ConstantFP : This class represents a floating point constant.
				1286	\begin{itemize}
				1287	<li><tt>double getValue () const</tt>: Returns the underlying value of this constant.
				1288	\end{itemize}
				1289	<li>ConstantBool : This represents a boolean constant.
				1290	\begin{itemize}
				1291	<li><tt>bool getValue () const</tt>: Returns the underlying value of this constant.
				1292	\end{itemize}
				1293	<li>ConstantArray : This represents a constant array.
				1294	\begin{itemize}
				1295	<li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
				1296	\end{itemize}
				1297	<li>ConstantStruct : This represents a constant struct.
				1298	\begin{itemize}
				1299	<li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
				1300	\end{itemize}
				1301	<li>ConstantPointerRef : This represents a constant pointer value that is initialized to point to a global value, which lies at a constant fixed address.
				1302	\begin{itemize}
				1303	<li><tt>GlobalValue *getValue()</tt>: Returns the global value to which this pointer is pointing to.
				1304	\end{itemize}
				1305	\end{itemize}
				1306
				1307
				1308	<!-- ======================================================================= -->
				1309	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				1310	<tr><td> </td><td width="100%">
				1311	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				1312	<a name="Type">The <tt>Type</tt> class and Derived Types</a>
				1313	</b></font></td></tr></table><ul>
				1314
				1315	Type as noted earlier is also a subclass of a Value class. Any primitive
				1316	type (like int, short etc) in LLVM is an instance of Type Class. All
				1317	other types are instances of subclasses of type like FunctionType,
				1318	ArrayType etc. DerivedType is the interface for all such dervied types
				1319	including FunctionType, ArrayType, PointerType, StructType. Types can have
				1320	names. They can be recursive (StructType). There exists exactly one instance
				1321	of any type structure at a time. This allows using pointer equality of Type *s for comparing types.
				1322
				1323	<!-- _______________________________________________________________________ -->
				1324	</ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
				1325
				1326	<li><tt>PrimitiveID getPrimitiveID () const</tt>: Returns the base type of the type.
				1327	<li><tt> bool isSigned () const</tt>: Returns whether an integral numeric type is signed. This is true for SByteTy, ShortTy, IntTy, LongTy. Note that this is not true for Float and Double.
				1328	<li><tt>bool isUnsigned () const</tt>: Returns whether a numeric type is unsigned. This is not quite the complement of isSigned... nonnumeric types return false as they do with isSigned. This returns true for UByteTy, UShortTy, UIntTy, and ULongTy.
				1329	<li><tt> bool isInteger () const</tt>: Equilivent to isSigned() \|\| isUnsigned(), but with only a single virtual function invocation.
				1330	<li><tt>bool isIntegral () const</tt>: Returns true if this is an integral type, which is either Bool type or one of the Integer types.
				1331
				1332	<li><tt>bool isFloatingPoint ()</tt>: Return true if this is one of the two floating point types.
				1333	<li><tt>bool isRecursive () const</tt>: Returns rue if the type graph contains a cycle.
				1334	<li><tt>isLosslesslyConvertableTo (const Type *Ty) const</tt>: Return true if this type can be converted to 'Ty' without any reinterpretation of bits. For example, uint to int.
				1335	<li><tt>bool isPrimitiveType () const</tt>: Returns true if it is a primitive type.
				1336	<li><tt>bool isDerivedType () const</tt>: Returns true if it is a derived type.
				1337	<li><tt>const Type * getContainedType (unsigned i) const</tt>:
				1338	This method is used to implement the type iterator. For derived types, this returns the types 'contained' in the derived type, returning 0 when 'i' becomes invalid. This allows the user to iterate over the types in a struct, for example, really easily.
				1339	<li><tt>unsigned getNumContainedTypes () const</tt>: Return the number of types in the derived type.
				1340
				1341
				1342
				1343	\subsection{Derived Types}
				1344	\begin{itemize}
				1345	<li>SequentialType : This is subclassed by ArrayType and PointerType
				1346	\begin{itemize}
				1347	<li><tt>const Type * getElementType () const</tt>: Returns the type of each of the elements in the sequential type.
				1348	\end{itemize}
				1349	<li>ArrayType : This is a subclass of SequentialType and defines interface for array types.
				1350	\begin{itemize}
				1351	<li><tt>unsigned getNumElements () const</tt>: Returns the number of elements in the array.
				1352	\end{itemize}
				1353	<li>PointerType : Subclass of SequentialType for pointer types.
				1354	<li>StructType : subclass of DerivedTypes for struct types
				1355	<li>FunctionType : subclass of DerivedTypes for function types.
				1356	\begin{itemize}
				1357
				1358	<li><tt>bool isVarArg () const</tt>: Returns true if its a vararg function
				1359	<li><tt> const Type * getReturnType () const</tt>: Returns the return type of the function.
				1360	<li><tt> const ParamTypes &getParamTypes () const</tt>: Returns a vector of parameter types.
				1361	<li><tt>const Type * getParamType (unsigned i)</tt>: Returns the type of the ith parameter.
				1362	<li><tt> const unsigned getNumParams () const</tt>: Returns the number of formal parameters.
				1363	\end{itemize}
				1364	\end{itemize}
				1365
				1366
				1367
				1368
				1369	<!-- ======================================================================= -->
				1370	</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
				1371	<tr><td> </td><td width="100%">
				1372	<font color="#EEEEFF" face="Georgia,Palatino"><b>
				1373	<a name="Argument">The <tt>Argument</tt> class</a>
				1374	</b></font></td></tr></table><ul>
				1375
				1376	This subclass of Value defines the interface for incoming formal arguments to a
				1377	function. A Function maitanis a list of its formal arguments. An argument has a
				1378	pointer to the parent Function.
				1379
				1380
				1381
				1382
				1383	<!-- *********************************************************************** -->
				1384	</ul>
				1385	<!-- *********************************************************************** -->
				1386
				1387	<hr><font size-1>
				1388	<address>By: <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
				1389	<a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
				1390	<!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
				1391	<!-- hhmts start -->
Chris Lattner	6b121f1	2002-09-10 15:20:46 +0000	[diff] [blame^]	1392	Last modified: Tue Sep 10 10:19:56 CDT 2002
Chris Lattner	9355b47	2002-09-06 02:50:58 +0000	[diff] [blame]	1393	<!-- hhmts end -->
				1394	</font></body></html>