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7 <tr><td> <font size=+3 color="#EEEEFF" face="Georgia,Palatino,Times,Roman"><b>LLVM Programmer's Manual</b></font></td>
11 <li><a href="#introduction">Introduction</a>
12 <li><a href="#general">General Information</a>
14 <li><a href="#stl">The C++ Standard Template Library</a>
15 <li><a href="#isa">The <tt>isa<></tt>, <tt>cast<></tt> and
16 <tt>dyn_cast<></tt> templates</a>
18 <li><a href="#common">Helpful Hints for Common Operations</a>
20 <li><a href="#inspection">Basic Inspection and Traversal Routines</a>
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>
26 <li><a href="#iterate_institer">Iterating over the <tt>Instruction</tt>s
27 in a <tt>Function</tt></a>
28 <li><a href="#iterate_convert">Turning an iterator into a class
30 <li><a href="#iterate_complex">Finding call sites: a more complex
32 <li><a href="#iterate_chains">Iterating over def-use & use-def
35 <li><a href="#simplechanges">Making simple changes</a>
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>
42 <li>Working with the Control Flow Graph
44 <li>Accessing predecessors and successors of a <tt>BasicBlock</tt>
50 <li>The general graph API
51 <li>The <tt>InstVisitor</tt> template
53 <li>The <tt>Statistic</tt> template
57 <li>Useful related topics
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
66 <li><a href="#coreclasses">The Core LLVM Class Hierarchy Reference</a>
68 <li><a href="#Value">The <tt>Value</tt> class</a>
70 <li><a href="#User">The <tt>User</tt> class</a>
72 <li><a href="#Instruction">The <tt>Instruction</tt> class</a>
76 <li><a href="#GlobalValue">The <tt>GlobalValue</tt> class</a>
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>
82 <li><a href="#Module">The <tt>Module</tt> class</a>
83 <li><a href="#Constant">The <tt>Constant</tt> class</a>
89 <li><a href="#Type">The <tt>Type</tt> class</a>
90 <li><a href="#Argument">The <tt>Argument</tt> class</a>
92 <li>The <tt>SymbolTable</tt> class
93 <li>The <tt>ilist</tt> and <tt>iplist</tt> classes
95 <li>Creating, inserting, moving and deleting from LLVM lists
97 <li>Important iterator invalidation semantics to be aware of
100 <p><b>Written by <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a>
101 <a href="mailto:sabre@nondot.org">Chris Lattner</a>, and
102 <a href="mailto:jstanley@cs.uiuc.edu">Joel Stanley</a></b><p>
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 <!-- *********************************************************************** -->
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
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>
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
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>
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 <!-- *********************************************************************** -->
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>
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>
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>
159 Here are some useful links:<p>
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>
165 <li><a href="http://www.parashift.com/c++-faq-lite/">C++ Frequently Asked
168 <li><a href="http://www.sgi.com/tech/stl/">SGI's STL Programmer's Guide</a> -
170 href="http://www.sgi.com/tech/stl/stl_introduction.html">Introduction to the
173 <li><a href="http://www.research.att.com/~bs/C++.html">Bjarne Stroustrup's C++
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>
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>
195 <!-- *********************************************************************** -->
196 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
197 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
198 <a name="common">Helpful Hints for Common Operations
199 </b></font></td></tr></table><ul>
200 <!-- *********************************************************************** -->
202 This section describes how to perform some very simple transformations of LLVM
203 code. This is meant to give examples of common idioms used, showing the
204 practical side of LLVM transformations.<p>
206 Because this is a "how-to" section, you should also read about the main classes
207 that you will be working with. The <a href="#coreclasses">Core LLVM Class
208 Hierarchy Reference</a> contains details and descriptions of the main classes
209 that you should know about.<p>
211 <!-- NOTE: this section should be heavy on example code -->
214 <!-- ======================================================================= -->
215 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
216 <tr><td> </td><td width="100%">
217 <font color="#EEEEFF" face="Georgia,Palatino"><b>
218 <a name="inspection">Basic Inspection and Traversal Routines</a>
219 </b></font></td></tr></table><ul>
221 The LLVM compiler infrastructure have many different data structures that may be
222 traversed. Following the example of the C++ standard template library, the
223 techniques used to traverse these various data structures are all basically the
224 same. For a enumerable sequence of values, the <tt>XXXbegin()</tt> function (or
225 method) returns an iterator to the start of the sequence, the <tt>XXXend()</tt>
226 function returns an iterator pointing to one past the last valid element of the
227 sequence, and there is some <tt>XXXiterator</tt> data type that is common
228 between the two operations.<p>
230 Because the pattern for iteration is common across many different aspects of the
231 program representation, the standard template library algorithms may be used on
232 them, and it is easier to remember how to iterate. First we show a few common
233 examples of the data structures that need to be traversed. Other data
234 structures are traversed in very similar ways.<p>
237 <!-- _______________________________________________________________________ -->
238 </ul><h4><a name="iterate_function"><hr size=0>Iterating over the <a
239 href="#BasicBlock"><tt>BasicBlock</tt></a>s in a <a
240 href="#Function"><tt>Function</tt></a> </h4><ul>
242 It's quite common to have a <tt>Function</tt> instance that you'd like
243 to transform in some way; in particular, you'd like to manipulate its
244 <tt>BasicBlock</tt>s. To facilitate this, you'll need to iterate over
245 all of the <tt>BasicBlock</tt>s that constitute the <tt>Function</tt>.
246 The following is an example that prints the name of a
247 <tt>BasicBlock</tt> and the number of <tt>Instruction</tt>s it
251 // func is a pointer to a Function instance
252 for(Function::iterator i = func->begin(), e = func->end(); i != e; ++i) {
254 // print out the name of the basic block if it has one, and then the
255 // number of instructions that it contains
257 cerr << "Basic block (name=" << i->getName() << ") has "
258 << i->size() << " instructions.\n";
262 Note that i can be used as if it were a pointer for the purposes of
263 invoking member functions of the <tt>Instruction</tt> class. This is
264 because the indirection operator is overloaded for the iterator
265 classes. In the above code, the expression <tt>i->size()</tt> is
266 exactly equivalent to <tt>(*i).size()</tt> just like you'd expect.
268 <!-- _______________________________________________________________________ -->
269 </ul><h4><a name="iterate_basicblock"><hr size=0>Iterating over the <a
270 href="#Instruction"><tt>Instruction</tt></a>s in a <a
271 href="#BasicBlock"><tt>BasicBlock</tt></a> </h4><ul>
273 Just like when dealing with <tt>BasicBlock</tt>s in
274 <tt>Function</tt>s, it's easy to iterate over the individual
275 instructions that make up <tt>BasicBlock</tt>s. Here's a code snippet
276 that prints out each instruction in a <tt>BasicBlock</tt>:
279 // blk is a pointer to a BasicBlock instance
280 for(BasicBlock::iterator i = blk->begin(), e = blk->end(); i != e; ++i)
281 // the next statement works since operator<<(ostream&,...)
282 // is overloaded for Instruction&
283 cerr << *i << "\n";
286 However, this isn't really the best way to print out the contents of a
287 <tt>BasicBlock</tt>! Since the ostream operators are overloaded for
288 virtually anything you'll care about, you could have just invoked the
289 print routine on the basic block itself: <tt>cerr << *blk <<
292 Note that currently operator<< is implemented for <tt>Value*</tt>, so it
293 will print out the contents of the pointer, instead of
294 the pointer value you might expect. This is a deprecated interface that will
295 be removed in the future, so it's best not to depend on it. To print out the
296 pointer value for now, you must cast to <tt>void*</tt>.<p>
299 <!-- _______________________________________________________________________ -->
300 </ul><h4><a name="iterate_institer"><hr size=0>Iterating over the <a
301 href="#Instruction"><tt>Instruction</tt></a>s in a <a
302 href="#Function"><tt>Function</tt></a></h4><ul>
304 If you're finding that you commonly iterate over a <tt>Function</tt>'s
305 <tt>BasicBlock</tt>s and then that <tt>BasicBlock</tt>'s
306 <tt>Instruction</tt>s, <tt>InstIterator</tt> should be used instead.
307 You'll need to include <a href="/doxygen/InstIterator_8h-source.html"><tt>llvm/Support/InstIterator.h</tt></a>, and then
308 instantiate <tt>InstIterator</tt>s explicitly in your code. Here's a
309 small example that shows how to dump all instructions in a function to
310 stderr (<b>Note:</b> Dereferencing an <tt>InstIterator</tt> yields an
311 <tt>Instruction*</tt>, <i>not</i> an <tt>Instruction&</tt>!):
314 #include "<a href="/doxygen/InstIterator_8h-source.html">llvm/Support/InstIterator.h</a>"
316 // Suppose F is a ptr to a function
317 for(inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)
318 cerr << **i << "\n";
321 Easy, isn't it? You can also use <tt>InstIterator</tt>s to fill a
322 worklist with its initial contents. For example, if you wanted to
323 initialize a worklist to contain all instructions in a
324 <tt>Function</tt> F, all you would need to do is something like:
327 std::set<Instruction*> worklist;
328 worklist.insert(inst_begin(F), inst_end(F));
331 The STL set <tt>worklist</tt> would now contain all instructions in
332 the <tt>Function</tt> pointed to by F.
334 <!-- _______________________________________________________________________ -->
335 </ul><h4><a name="iterate_convert"><hr size=0>Turning an iterator into a class
336 pointer (and vice-versa) </h4><ul>
338 Sometimes, it'll be useful to grab a reference (or pointer) to a class
339 instance when all you've got at hand is an iterator. Well, extracting
340 a reference or a pointer from an iterator is very straightforward.
341 Assuming that <tt>i</tt> is a <tt>BasicBlock::iterator</tt> and
342 <tt>j</tt> is a <tt>BasicBlock::const_iterator</tt>:
345 Instruction& inst = *i; // grab reference to instruction reference
346 Instruction* pinst = &*i; // grab pointer to instruction reference
347 const Instruction& inst = *j;
349 However, the iterators you'll be working with in the LLVM framework
350 are special: they will automatically convert to a ptr-to-instance type
351 whenever they need to. Instead of dereferencing the iterator and then
352 taking the address of the result, you can simply assign the iterator
353 to the proper pointer type and you get the dereference and address-of
354 operation as a result of the assignment (behind the scenes, this is a
355 result of overloading casting mechanisms). Thus the last line of the
358 <pre>Instruction* pinst = &*i;</pre>
360 is semantically equivalent to
362 <pre>Instruction* pinst = i;</pre>
364 <b>Caveat emptor</b>: The above syntax works <i>only</i> when you're
365 <i>not</i> working with <tt>dyn_cast</tt>. The template definition of
366 <tt>dyn_cast</tt> isn't implemented to handle this yet, so you'll
367 still need the following in order for things to work properly:
370 BasicBlock::iterator bbi = ...;
371 <a href="#BranchInst">BranchInst</a>* b = <a href="#isa">dyn_cast</a><<a href="#BranchInst">BranchInst</a>>(&*bbi);
374 It's also possible to turn a class pointer into the corresponding
375 iterator. Usually, this conversion is quite inexpensive. The
376 following code snippet illustrates use of the conversion constructors
377 provided by LLVM iterators. By using these, you can explicitly grab
378 the iterator of something without actually obtaining it via iteration
382 void printNextInstruction(Instruction* inst) {
383 BasicBlock::iterator it(inst);
384 ++it; // after this line, it refers to the instruction after *inst.
385 if(it != inst->getParent()->end()) cerr << *it << "\n";
388 Of course, this example is strictly pedagogical, because it'd be much
389 better to explicitly grab the next instruction directly from inst.
391 <!-- dereferenced iterator = Class &
392 iterators have converting constructor for 'Class *'
393 iterators automatically convert to 'Class *' except in dyn_cast<> case
396 <!--_______________________________________________________________________-->
397 </ul><h4><a name="iterate_complex"><hr size=0>Finding call sites: a slightly
398 more complex example </h4><ul>
400 Say that you're writing a FunctionPass and would like to count all the
401 locations in the entire module (that is, across every
402 <tt>Function</tt>) where a certain function (i.e. some
403 <tt>Function</tt>*) already in scope. As you'll learn later, you may
404 want to use an <tt>InstVisitor</tt> to accomplish this in a much more
405 straightforward manner, but this example will allow us to explore how
406 you'd do it if you didn't have <tt>InstVisitor</tt> around. In
407 pseudocode, this is what we want to do:
410 initialize callCounter to zero
411 for each Function f in the Module
412 for each BasicBlock b in f
413 for each Instruction i in b
414 if(i is a CallInst and calls the given function)
415 increment callCounter
418 And the actual code is (remember, since we're writing a
419 <tt>FunctionPass</tt>, our <tt>FunctionPass</tt>-derived class simply
420 has to override the <tt>runOnFunction</tt> method...):
424 Function* targetFunc = ...;
426 class OurFunctionPass : public FunctionPass {
428 OurFunctionPass(): callCounter(0) { }
430 virtual runOnFunction(Function& F) {
431 for(Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
432 for(BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {
433 if (<a href="#CallInst">CallInst</a>* callInst = dyn_cast<<a href="#CallInst">CallInst</a>>(&*inst)) {
434 // we know we've encountered a call instruction, so we
435 // need to determine if it's a call to the
436 // function pointed to by m_func or not.
438 if(callInst->getCalledFunction() == targetFunc)
445 unsigned callCounter;
449 <!--_______________________________________________________________________-->
450 </ul><h4><a name="iterate_chains"><hr size=0>Iterating over def-use &
451 use-def chains</h4><ul>
454 def-use chains ("finding all users of"): Value::use_begin/use_end
455 use-def chains ("finding all values used"): User::op_begin/op_end [op=operand]
458 <!-- ======================================================================= -->
459 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
460 <tr><td> </td><td width="100%">
461 <font color="#EEEEFF" face="Georgia,Palatino"><b>
462 <a name="simplechanges">Making simple changes</a>
463 </b></font></td></tr></table><ul>
465 <!-- Value::replaceAllUsesWith
466 User::replaceUsesOfWith
467 Point out: include/llvm/Transforms/Utils/
468 especially BasicBlockUtils.h with:
469 ReplaceInstWithValue, ReplaceInstWithInst
474 <!-- *********************************************************************** -->
475 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
476 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
477 <a name="coreclasses">The Core LLVM Class Hierarchy Reference
478 </b></font></td></tr></table><ul>
479 <!-- *********************************************************************** -->
481 The Core LLVM classes are the primary means of representing the program being
482 inspected or transformed. The core LLVM classes are defined in header files in
483 the <tt>include/llvm/</tt> directory, and implemented in the <tt>lib/VMCore</tt>
487 <!-- ======================================================================= -->
488 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
489 <tr><td> </td><td width="100%">
490 <font color="#EEEEFF" face="Georgia,Palatino"><b>
491 <a name="Value">The <tt>Value</tt> class</a>
492 </b></font></td></tr></table><ul>
494 <tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt></b><br>
495 doxygen info: <a href="/doxygen/classValue.html">Value Class</a><p>
498 The <tt>Value</tt> class is the most important class in LLVM Source base. It
499 represents a typed value that may be used (among other things) as an operand to
500 an instruction. There are many different types of <tt>Value</tt>s, such as <a
501 href="#Constant"><tt>Constant</tt></a>s, <a
502 href="#Argument"><tt>Argument</tt></a>s, and even <a
503 href="#Instruction"><tt>Instruction</tt></a>s and <a
504 href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.<p>
506 A particular <tt>Value</tt> may be used many times in the LLVM representation
507 for a program. For example, an incoming argument to a function (represented
508 with an instance of the <a href="#Argument">Argument</a> class) is "used" by
509 every instruction in the function that references the argument. To keep track
510 of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
511 href="#User"><tt>User</tt></a>s that is using it (the <a
512 href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
513 graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
514 def-use information in the program, and is accessible through the <tt>use_</tt>*
515 methods, shown below.<p>
517 Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed, and
518 this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
519 method. <a name="#nameWarning">In addition, all LLVM values can be named. The
520 "name" of the <tt>Value</tt> is symbolic string printed in the LLVM code:<p>
523 %<b>foo</b> = add int 1, 2
526 The name of this instruction is "foo". <b>NOTE</b> that the name of any value
527 may be missing (an empty string), so names should <b>ONLY</b> be used for
528 debugging (making the source code easier to read, debugging printouts), they
529 should not be used to keep track of values or map between them. For this
530 purpose, use a <tt>std::map</tt> of pointers to the <tt>Value</tt> itself
533 One important aspect of LLVM is that there is no distinction between an SSA
534 variable and the operation that produces it. Because of this, any reference to
535 the value produced by an instruction (or the value available as an incoming
536 argument, for example) is represented as a direct pointer to the class that
537 represents this value. Although this may take some getting used to, it
538 simplifies the representation and makes it easier to manipulate.<p>
541 <!-- _______________________________________________________________________ -->
542 </ul><h4><a name="m_Value"><hr size=0>Important Public Members of
543 the <tt>Value</tt> class</h4><ul>
545 <li><tt>Value::use_iterator</tt> - Typedef for iterator over the use-list<br>
546 <tt>Value::use_const_iterator</tt>
547 - Typedef for const_iterator over the use-list<br>
548 <tt>unsigned use_size()</tt> - Returns the number of users of the value.<br>
549 <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
550 <tt>use_iterator use_begin()</tt>
551 - Get an iterator to the start of the use-list.<br>
552 <tt>use_iterator use_end()</tt>
553 - Get an iterator to the end of the use-list.<br>
554 <tt><a href="#User">User</a> *use_back()</tt>
555 - Returns the last element in the list.<p>
557 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>
559 <li><tt><a href="#Type">Type</a> *getType() const</tt><p>
560 This method returns the Type of the Value.
562 <li><tt>bool hasName() const</tt><br>
563 <tt>std::string getName() const</tt><br>
564 <tt>void setName(const std::string &Name)</tt><p>
566 This family of methods is used to access and assign a name to a <tt>Value</tt>,
567 be aware of the <a href="#nameWarning">precaution above</a>.<p>
570 <li><tt>void replaceAllUsesWith(Value *V)</tt><p>
572 This method traverses the use list of a <tt>Value</tt> changing all <a
573 href="#User"><tt>User</tt>'s</a> of the current value to refer to "<tt>V</tt>"
574 instead. For example, if you detect that an instruction always produces a
575 constant value (for example through constant folding), you can replace all uses
576 of the instruction with the constant like this:<p>
579 Inst->replaceAllUsesWith(ConstVal);
584 <!-- ======================================================================= -->
585 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
586 <tr><td> </td><td width="100%">
587 <font color="#EEEEFF" face="Georgia,Palatino"><b>
588 <a name="User">The <tt>User</tt> class</a>
589 </b></font></td></tr></table><ul>
591 <tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt></b><br>
592 doxygen info: <a href="/doxygen/classUser.html">User Class</a><br>
593 Superclass: <a href="#Value"><tt>Value</tt></a><p>
596 The <tt>User</tt> class is the common base class of all LLVM nodes that may
597 refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
598 that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
599 referring to. The <tt>User</tt> class itself is a subclass of
602 The operands of a <tt>User</tt> point directly to the LLVM <a
603 href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
604 Single Assignment (SSA) form, there can only be one definition referred to,
605 allowing this direct connection. This connection provides the use-def
606 information in LLVM.<p>
608 <!-- _______________________________________________________________________ -->
609 </ul><h4><a name="m_User"><hr size=0>Important Public Members of
610 the <tt>User</tt> class</h4><ul>
612 The <tt>User</tt> class exposes the operand list in two ways: through an index
613 access interface and through an iterator based interface.<p>
615 <li><tt>Value *getOperand(unsigned i)</tt><br>
616 <tt>unsigned getNumOperands()</tt><p>
618 These two methods expose the operands of the <tt>User</tt> in a convenient form
619 for direct access.<p>
621 <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand list<br>
622 <tt>User::op_const_iterator</tt>
623 <tt>use_iterator op_begin()</tt>
624 - Get an iterator to the start of the operand list.<br>
625 <tt>use_iterator op_end()</tt>
626 - Get an iterator to the end of the operand list.<p>
628 Together, these methods make up the iterator based interface to the operands of
633 <!-- ======================================================================= -->
634 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
635 <tr><td> </td><td width="100%">
636 <font color="#EEEEFF" face="Georgia,Palatino"><b>
637 <a name="Instruction">The <tt>Instruction</tt> class</a>
638 </b></font></td></tr></table><ul>
641 href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt></b><br>
642 doxygen info: <a href="/doxygen/classInstruction.html">Instruction Class</a><br>
643 Superclasses: <a href="#User"><tt>User</tt></a>, <a
644 href="#Value"><tt>Value</tt></a><p>
646 The <tt>Instruction</tt> class is the common base class for all LLVM
647 instructions. It provides only a few methods, but is a very commonly used
648 class. The primary data tracked by the <tt>Instruction</tt> class itself is the
649 opcode (instruction type) and the parent <a
650 href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
651 into. To represent a specific type of instruction, one of many subclasses of
652 <tt>Instruction</tt> are used.<p>
654 Because the <tt>Instruction</tt> class subclasses the <a
655 href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
656 way as for other <a href="#User"><tt>User</tt></a>s (with the
657 <tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
658 <tt>op_begin()</tt>/<tt>op_end()</tt> methods).<p>
661 <!-- _______________________________________________________________________ -->
662 </ul><h4><a name="m_Instruction"><hr size=0>Important Public Members of
663 the <tt>Instruction</tt> class</h4><ul>
665 <li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt><p>
667 Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that this
668 <tt>Instruction</tt> is embedded into.<p>
670 <li><tt>bool hasSideEffects()</tt><p>
672 Returns true if the instruction has side effects, i.e. it is a <tt>call</tt>,
673 <tt>free</tt>, <tt>invoke</tt>, or <tt>store</tt>.<p>
675 <li><tt>unsigned getOpcode()</tt><p>
677 Returns the opcode for the <tt>Instruction</tt>.<p>
681 \subsection{Subclasses of Instruction :}
683 <li>BinaryOperator : This subclass of Instruction defines a general interface to the all the instructions involvong binary operators in LLVM.
685 <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.
687 <li>TerminatorInst : This subclass of Instructions defines an interface for all instructions that can terminate a BasicBlock.
689 <li> <tt>unsigned getNumSuccessors()</tt>: Returns the number of successors for this terminator instruction.
690 <li><tt>BasicBlock *getSuccessor(unsigned i)</tt>: As the name suggests returns the ith successor BasicBlock.
691 <li><tt>void setSuccessor(unsigned i, BasicBlock *B)</tt>: sets BasicBlock B as the ith succesor to this terminator instruction.
694 <li>PHINode : This represents the PHI instructions in the SSA form.
696 <li><tt> unsigned getNumIncomingValues()</tt>: Returns the number of incoming edges to this PHI node.
697 <li><tt> Value *getIncomingValue(unsigned i)</tt>: Returns the ith incoming Value.
698 <li><tt>void setIncomingValue(unsigned i, Value *V)</tt>: Sets the ith incoming Value as V
699 <li><tt>BasicBlock *getIncomingBlock(unsigned i)</tt>: Returns the Basic Block corresponding to the ith incoming Value.
700 <li><tt> void addIncoming(Value *D, BasicBlock *BB)</tt>:
701 Add an incoming value to the end of the PHI list
702 <li><tt> int getBasicBlockIndex(const BasicBlock *BB) const</tt>:
703 Returns the first index of the specified basic block in the value list for this PHI. Returns -1 if no instance.
705 <li>CastInst : In LLVM all casts have to be done through explicit cast instructions. CastInst defines the interface to the cast instructions.
706 <li>CallInst : This defines an interface to the call instruction in LLVM. ARguments to the function are nothing but operands of the instruction.
708 <li>: <tt>Function *getCalledFunction()</tt>: Returns a handle to the function that is being called by this Function.
710 <li>LoadInst, StoreInst, GetElemPtrInst : These subclasses represent load, store and getelementptr instructions in LLVM.
712 <li><tt>Value * getPointerOperand ()</tt>: Returns the Pointer Operand which is typically the 0th operand.
714 <li>BranchInst : This is a subclass of TerminatorInst and defines the interface for conditional and unconditional branches in LLVM.
716 <li><tt>bool isConditional()</tt>: Returns true if the branch is a conditional branch else returns false
717 <li> <tt>Value *getCondition()</tt>: Returns the condition if it is a conditional branch else returns null.
718 <li> <tt>void setUnconditionalDest(BasicBlock *Dest)</tt>: Changes the current branch to an unconditional one targetting the specified block.
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="BasicBlock">The <tt>BasicBlock</tt> class</a>
731 </b></font></td></tr></table><ul>
734 href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt></b><br>
735 doxygen info: <a href="/doxygen/classBasicBlock.html">BasicBlock Class</a><br>
736 Superclass: <a href="#Value"><tt>Value</tt></a><p>
739 This class represents a single entry multiple exit section of the code, commonly
740 known as a basic block by the compiler community. The <tt>BasicBlock</tt> class
741 maintains a list of <a href="#Instruction"><tt>Instruction</tt></a>s, which form
742 the body of the block. Matching the language definition, the last element of
743 this list of instructions is always a terminator instruction (a subclass of the
744 <a href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).<p>
746 In addition to tracking the list of instructions that make up the block, the
747 <tt>BasicBlock</tt> class also keeps track of the <a
748 href="#Function"><tt>Function</tt></a> that it is embedded into.<p>
750 Note that <tt>BasicBlock</tt>s themselves are <a
751 href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
752 like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
756 <!-- _______________________________________________________________________ -->
757 </ul><h4><a name="m_BasicBlock"><hr size=0>Important Public Members of
758 the <tt>BasicBlock</tt> class</h4><ul>
760 <li><tt>BasicBlock(const std::string &Name = "", <a
761 href="#Function">Function</a> *Parent = 0)</tt><p>
763 The <tt>BasicBlock</tt> constructor is used to create new basic blocks for
764 insertion into a function. The constructor simply takes a name for the new
765 block, and optionally a <a href="#Function"><tt>Function</tt></a> to insert it
766 into. If the <tt>Parent</tt> parameter is specified, the new
767 <tt>BasicBlock</tt> is automatically inserted at the end of the specified <a
768 href="#Function"><tt>Function</tt></a>, if not specified, the BasicBlock must be
769 manually inserted into the <a href="#Function"><tt>Function</tt></a>.<p>
771 <li><tt>BasicBlock::iterator</tt> - Typedef for instruction list iterator<br>
772 <tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
773 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
774 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
776 These methods and typedefs are forwarding functions that have the same semantics
777 as the standard library methods of the same names. These methods expose the
778 underlying instruction list of a basic block in a way that is easy to
779 manipulate. To get the full complement of container operations (including
780 operations to update the list), you must use the <tt>getInstList()</tt>
783 <li><tt>BasicBlock::InstListType &getInstList()</tt><p>
785 This method is used to get access to the underlying container that actually
786 holds the Instructions. This method must be used when there isn't a forwarding
787 function in the <tt>BasicBlock</tt> class for the operation that you would like
788 to perform. Because there are no forwarding functions for "updating"
789 operations, you need to use this if you want to update the contents of a
790 <tt>BasicBlock</tt>.<p>
792 <li><tt><A href="#Function">Function</a> *getParent()</tt><p>
794 Returns a pointer to <a href="#Function"><tt>Function</tt></a> the block is
795 embedded into, or a null pointer if it is homeless.<p>
797 <li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt><p>
799 Returns a pointer to the terminator instruction that appears at the end of the
800 <tt>BasicBlock</tt>. If there is no terminator instruction, or if the last
801 instruction in the block is not a terminator, then a null pointer is
805 <!-- ======================================================================= -->
806 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
807 <tr><td> </td><td width="100%">
808 <font color="#EEEEFF" face="Georgia,Palatino"><b>
809 <a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
810 </b></font></td></tr></table><ul>
813 href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt></b><br>
814 doxygen info: <a href="/doxygen/classGlobalValue.html">GlobalValue Class</a><br>
815 Superclasses: <a href="#User"><tt>User</tt></a>, <a
816 href="#Value"><tt>Value</tt></a><p>
818 Global values (<A href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
819 href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
820 visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
821 Because they are visible at global scope, they are also subject to linking with
822 other globals defined in different translation units. To control the linking
823 process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
824 <tt>GlobalValue</tt>s know whether they have internal or external linkage.<p>
826 If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
827 <tt>static</tt> in C), it is not visible to code outside the current translation
828 unit, and does not participate in linking. If it has external linkage, it is
829 visible to external code, and does participate in linking. In addition to
830 linkage information, <tt>GlobalValue</tt>s keep track of which <a
831 href="#Module"><tt>Module</tt></a> they are currently part of.<p>
833 Because <tt>GlobalValue</tt>s are memory objects, they are always referred to by
834 their address. As such, the <a href="#Type"><tt>Type</tt></a> of a global is
835 always a pointer to its contents. This is explained in the LLVM Language
839 <!-- _______________________________________________________________________ -->
840 </ul><h4><a name="m_GlobalValue"><hr size=0>Important Public Members of
841 the <tt>GlobalValue</tt> class</h4><ul>
843 <li><tt>bool hasInternalLinkage() const</tt><br>
844 <tt>bool hasExternalLinkage() const</tt><br>
845 <tt>void setInternalLinkage(bool HasInternalLinkage)</tt><p>
847 These methods manipulate the linkage characteristics of the
848 <tt>GlobalValue</tt>.<p>
850 <li><tt><a href="#Module">Module</a> *getParent()</tt><p>
852 This returns the <a href="#Module"><tt>Module</tt></a> that the GlobalValue is
853 currently embedded into.<p>
857 <!-- ======================================================================= -->
858 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
859 <tr><td> </td><td width="100%">
860 <font color="#EEEEFF" face="Georgia,Palatino"><b>
861 <a name="Function">The <tt>Function</tt> class</a>
862 </b></font></td></tr></table><ul>
865 href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt></b><br>
866 doxygen info: <a href="/doxygen/classFunction.html">Function Class</a><br>
867 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
868 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
870 The <tt>Function</tt> class represents a single procedure in LLVM. It is
871 actually one of the more complex classes in the LLVM heirarchy because it must
872 keep track of a large amount of data. The <tt>Function</tt> class keeps track
873 of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
874 href="#Argument"><tt>Argument</tt></a>s, and a <a
875 href="#SymbolTable"><tt>SymbolTable</tt></a>.<p>
877 The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most commonly
878 used part of <tt>Function</tt> objects. The list imposes an implicit ordering
879 of the blocks in the function, which indicate how the code will be layed out by
880 the backend. Additionally, the first <a
881 href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
882 <tt>Function</tt>. It is not legal in LLVM explicitly branch to this initial
883 block. There are no implicit exit nodes, and in fact there may be multiple exit
884 nodes from a single <tt>Function</tt>. If the <a
885 href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
886 the <tt>Function</tt> is actually a function declaration: the actual body of the
887 function hasn't been linked in yet.<p>
889 In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
890 <tt>Function</tt> class also keeps track of the list of formal <a
891 href="#Argument"><tt>Argument</tt></a>s that the function receives. This
892 container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
893 nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
894 the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.<p>
896 The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used LLVM
897 feature that is only used when you have to look up a value by name. Aside from
898 that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used internally to
899 make sure that there are not conflicts between the names of <a
900 href="#Instruction"><tt>Instruction</tt></a>s, <a
901 href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
902 href="#Argument"><tt>Argument</tt></a>s in the function body.<p>
905 <!-- _______________________________________________________________________ -->
906 </ul><h4><a name="m_Function"><hr size=0>Important Public Members of
907 the <tt>Function</tt> class</h4><ul>
909 <li><tt>Function(const <a href="#FunctionType">FunctionType</a> *Ty, bool isInternal, const std::string &N = "")</tt><p>
911 Constructor used when you need to create new <tt>Function</tt>s to add the the
912 program. The constructor must specify the type of the function to create and
913 whether or not it should start out with internal or external linkage.<p>
915 <li><tt>bool isExternal()</tt><p>
917 Return whether or not the <tt>Function</tt> has a body defined. If the function
918 is "external", it does not have a body, and thus must be resolved by linking
919 with a function defined in a different translation unit.<p>
922 <li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
923 <tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
924 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
925 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
927 These are forwarding methods that make it easy to access the contents of a
928 <tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
931 <li><tt>Function::BasicBlockListType &getBasicBlockList()</tt><p>
933 Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This is
934 neccesary to use when you need to update the list or perform a complex action
935 that doesn't have a forwarding method.<p>
938 <li><tt>Function::aiterator</tt> - Typedef for the argument list iterator<br>
939 <tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
940 <tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
941 <tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt><p>
943 These are forwarding methods that make it easy to access the contents of a
944 <tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a> list.<p>
946 <li><tt>Function::ArgumentListType &getArgumentList()</tt><p>
948 Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This is
949 neccesary to use when you need to update the list or perform a complex action
950 that doesn't have a forwarding method.<p>
954 <li><tt><a href="#BasicBlock">BasicBlock</a> &getEntryNode()</tt><p>
956 Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
957 function. Because the entry block for the function is always the first block,
958 this returns the first block of the <tt>Function</tt>.<p>
960 <li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
961 <tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt><p>
963 This traverses the <a href="#Type"><tt>Type</tt></a> of the <tt>Function</tt>
964 and returns the return type of the function, or the <a
965 href="#FunctionType"><tt>FunctionType</tt></a> of the actual function.<p>
968 <li><tt>bool hasSymbolTable() const</tt><p>
970 Return true if the <tt>Function</tt> has a symbol table allocated to it and if
971 there is at least one entry in it.<p>
973 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
975 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
976 <tt>Function</tt> or a null pointer if one has not been allocated (because there
977 are no named values in the function).<p>
979 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
981 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
982 <tt>Function</tt> or allocate a new <a
983 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
984 should only be used when adding elements to the <a
985 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
986 not left laying around.<p>
990 <!-- ======================================================================= -->
991 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
992 <tr><td> </td><td width="100%">
993 <font color="#EEEEFF" face="Georgia,Palatino"><b>
994 <a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
995 </b></font></td></tr></table><ul>
998 href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt></b><br>
999 doxygen info: <a href="/doxygen/classGlobalVariable.html">GlobalVariable Class</a><br>
1000 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
1001 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
1003 Global variables are represented with the (suprise suprise)
1004 <tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are
1005 also subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such
1006 are always referenced by their address (global values must live in memory, so
1007 their "name" refers to their address). Global variables may have an initial
1008 value (which must be a <a href="#Constant"><tt>Constant</tt></a>), and if they
1009 have an initializer, they may be marked as "constant" themselves (indicating
1010 that their contents never change at runtime).<p>
1013 <!-- _______________________________________________________________________ -->
1014 </ul><h4><a name="m_GlobalVariable"><hr size=0>Important Public Members of the
1015 <tt>GlobalVariable</tt> class</h4><ul>
1017 <li><tt>GlobalVariable(const <a href="#Type">Type</a> *Ty, bool isConstant, bool
1018 isInternal, <a href="#Constant">Constant</a> *Initializer = 0, const std::string
1019 &Name = "")</tt><p>
1021 Create a new global variable of the specified type. If <tt>isConstant</tt> is
1022 true then the global variable will be marked as unchanging for the program, and
1023 if <tt>isInternal</tt> is true the resultant global variable will have internal
1024 linkage. Optionally an initializer and name may be specified for the global variable as well.<p>
1027 <li><tt>bool isConstant() const</tt><p>
1029 Returns true if this is a global variable is known not to be modified at
1033 <li><tt>bool hasInitializer()</tt><p>
1035 Returns true if this <tt>GlobalVariable</tt> has an intializer.<p>
1038 <li><tt><a href="#Constant">Constant</a> *getInitializer()</tt><p>
1040 Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal to call
1041 this method if there is no initializer.<p>
1044 <!-- ======================================================================= -->
1045 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1046 <tr><td> </td><td width="100%">
1047 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1048 <a name="Module">The <tt>Module</tt> class</a>
1049 </b></font></td></tr></table><ul>
1052 href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt></b><br>
1053 doxygen info: <a href="/doxygen/classModule.html">Module Class</a><p>
1055 The <tt>Module</tt> class represents the top level structure present in LLVM
1056 programs. An LLVM module is effectively either a translation unit of the
1057 original program or a combination of several translation units merged by the
1058 linker. The <tt>Module</tt> class keeps track of a list of <a
1059 href="#Function"><tt>Function</tt></a>s, a list of <a
1060 href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
1061 href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
1062 helpful member functions that try to make common operations easy.<p>
1065 <!-- _______________________________________________________________________ -->
1066 </ul><h4><a name="m_Module"><hr size=0>Important Public Members of the
1067 <tt>Module</tt> class</h4><ul>
1069 <li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
1070 <tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
1071 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
1072 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
1074 These are forwarding methods that make it easy to access the contents of a
1075 <tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
1078 <li><tt>Module::FunctionListType &getFunctionList()</tt><p>
1080 Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
1081 neccesary to use when you need to update the list or perform a complex action
1082 that doesn't have a forwarding method.<p>
1084 <!-- Global Variable -->
1087 <li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
1088 <tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
1089 <tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
1090 <tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt><p>
1092 These are forwarding methods that make it easy to access the contents of a
1093 <tt>Module</tt> object's <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>
1096 <li><tt>Module::GlobalListType &getGlobalList()</tt><p>
1098 Returns the list of <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s.
1099 This is neccesary to use when you need to update the list or perform a complex
1100 action that doesn't have a forwarding method.<p>
1103 <!-- Symbol table stuff -->
1106 <li><tt>bool hasSymbolTable() const</tt><p>
1108 Return true if the <tt>Module</tt> has a symbol table allocated to it and if
1109 there is at least one entry in it.<p>
1111 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
1113 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1114 <tt>Module</tt> or a null pointer if one has not been allocated (because there
1115 are no named values in the function).<p>
1117 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
1119 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1120 <tt>Module</tt> or allocate a new <a
1121 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
1122 should only be used when adding elements to the <a
1123 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
1124 not left laying around.<p>
1127 <!-- Convenience methods -->
1130 <li><tt><a href="#Function">Function</a> *getFunction(const std::string &Name, const <a href="#FunctionType">FunctionType</a> *Ty)</tt><p>
1132 Look up the specified function in the <tt>Module</tt> <a
1133 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
1137 <li><tt><a href="#Function">Function</a> *getOrInsertFunction(const std::string
1138 &Name, const <a href="#FunctionType">FunctionType</a> *T)</tt><p>
1140 Look up the specified function in the <tt>Module</tt> <a
1141 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, add an
1142 external declaration for the function and return it.<p>
1145 <li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt><p>
1147 If there is at least one entry in the <a
1148 href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
1149 href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
1153 <li><tt>bool addTypeName(const std::string &Name, const <a href="#Type">Type</a>
1156 Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a> mapping
1157 <tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this name, true
1158 is returned and the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is not
1162 <!-- ======================================================================= -->
1163 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1164 <tr><td> </td><td width="100%">
1165 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1166 <a name="Constant">The <tt>Constant</tt> class and subclasses</a>
1167 </b></font></td></tr></table><ul>
1169 Constant represents a base class for different types of constants. It is
1170 subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
1171 ConstantArray etc for representing the various types of Constants.<p>
1174 <!-- _______________________________________________________________________ -->
1175 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1177 <li><tt>bool isConstantExpr()</tt>: Returns true if it is a ConstantExpr
1182 \subsection{Important Subclasses of Constant}
1184 <li>ConstantSInt : This subclass of Constant represents a signed integer constant.
1186 <li><tt>int64_t getValue () const</tt>: Returns the underlying value of this constant.
1188 <li>ConstantUInt : This class represents an unsigned integer.
1190 <li><tt>uint64_t getValue () const</tt>: Returns the underlying value of this constant.
1192 <li>ConstantFP : This class represents a floating point constant.
1194 <li><tt>double getValue () const</tt>: Returns the underlying value of this constant.
1196 <li>ConstantBool : This represents a boolean constant.
1198 <li><tt>bool getValue () const</tt>: Returns the underlying value of this constant.
1200 <li>ConstantArray : This represents a constant array.
1202 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1204 <li>ConstantStruct : This represents a constant struct.
1206 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1208 <li>ConstantPointerRef : This represents a constant pointer value that is initialized to point to a global value, which lies at a constant fixed address.
1210 <li><tt>GlobalValue *getValue()</tt>: Returns the global value to which this pointer is pointing to.
1215 <!-- ======================================================================= -->
1216 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1217 <tr><td> </td><td width="100%">
1218 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1219 <a name="Type">The <tt>Type</tt> class and Derived Types</a>
1220 </b></font></td></tr></table><ul>
1222 Type as noted earlier is also a subclass of a Value class. Any primitive
1223 type (like int, short etc) in LLVM is an instance of Type Class. All
1224 other types are instances of subclasses of type like FunctionType,
1225 ArrayType etc. DerivedType is the interface for all such dervied types
1226 including FunctionType, ArrayType, PointerType, StructType. Types can have
1227 names. They can be recursive (StructType). There exists exactly one instance
1228 of any type structure at a time. This allows using pointer equality of Type *s for comparing types.
1230 <!-- _______________________________________________________________________ -->
1231 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1233 <li><tt>PrimitiveID getPrimitiveID () const</tt>: Returns the base type of the type.
1234 <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.
1235 <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.
1236 <li><tt> bool isInteger () const</tt>: Equilivent to isSigned() || isUnsigned(), but with only a single virtual function invocation.
1237 <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.
1239 <li><tt>bool isFloatingPoint ()</tt>: Return true if this is one of the two floating point types.
1240 <li><tt>bool isRecursive () const</tt>: Returns rue if the type graph contains a cycle.
1241 <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.
1242 <li><tt>bool isPrimitiveType () const</tt>: Returns true if it is a primitive type.
1243 <li><tt>bool isDerivedType () const</tt>: Returns true if it is a derived type.
1244 <li><tt>const Type * getContainedType (unsigned i) const</tt>:
1245 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.
1246 <li><tt>unsigned getNumContainedTypes () const</tt>: Return the number of types in the derived type.
1250 \subsection{Derived Types}
1252 <li>SequentialType : This is subclassed by ArrayType and PointerType
1254 <li><tt>const Type * getElementType () const</tt>: Returns the type of each of the elements in the sequential type.
1256 <li>ArrayType : This is a subclass of SequentialType and defines interface for array types.
1258 <li><tt>unsigned getNumElements () const</tt>: Returns the number of elements in the array.
1260 <li>PointerType : Subclass of SequentialType for pointer types.
1261 <li>StructType : subclass of DerivedTypes for struct types
1262 <li>FunctionType : subclass of DerivedTypes for function types.
1265 <li><tt>bool isVarArg () const</tt>: Returns true if its a vararg function
1266 <li><tt> const Type * getReturnType () const</tt>: Returns the return type of the function.
1267 <li><tt> const ParamTypes &getParamTypes () const</tt>: Returns a vector of parameter types.
1268 <li><tt>const Type * getParamType (unsigned i)</tt>: Returns the type of the ith parameter.
1269 <li><tt> const unsigned getNumParams () const</tt>: Returns the number of formal parameters.
1276 <!-- ======================================================================= -->
1277 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1278 <tr><td> </td><td width="100%">
1279 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1280 <a name="Argument">The <tt>Argument</tt> class</a>
1281 </b></font></td></tr></table><ul>
1283 This subclass of Value defines the interface for incoming formal arguments to a
1284 function. A Function maitanis a list of its formal arguments. An argument has a
1285 pointer to the parent Function.
1290 <!-- *********************************************************************** -->
1292 <!-- *********************************************************************** -->
1295 <address>By: <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
1296 <a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
1297 <!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
1298 <!-- hhmts start -->
1299 Last modified: Mon Sep 9 14:56:55 CDT 2002
1301 </font></body></html>