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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>
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>The isa<>, cast<> and dyn_cast<> templates
17 <li><a href="#common">Helpful Hints for Common Operations</a>
19 <li><a href="#inspection">Basic Inspection and Traversal Routines</a>
21 <li><a href="#iterate_function">Iterating over the <tt>BasicBlock</tt>s
22 in a <tt>Function</tt></a>
23 <li><a href="#iterate_basicblock">Iterating over the <tt>Instruction</tt>s
24 in a <tt>BasicBlock</tt></a>
25 <li><a href="#iterate_convert">Turning an iterator into a class
27 <li><a href="#iterate_complex">Finding call sites: a more complex
30 <li><a href="#simplechanges">Making simple changes</a>
32 <li>Creating and inserting new <tt>Instruction</tt>s
33 <li>Deleting <tt>Instruction</tt>s
34 <li>Replacing an <tt>Instruction</tt> with another <tt>Value</tt>
37 <li>Working with the Control Flow Graph
39 <li>Accessing predecessors and successors of a <tt>BasicBlock</tt>
46 <li>isa<>, cast<>, and dyn_cast<> templates
48 <li>The general graph API
49 <li>The <tt>InstVisitor</tt> template
51 <li>The <tt>Statistic</tt> template
55 <li>Useful related topics
57 <li>The <tt>-time-passes</tt> option
58 <li>How to use the LLVM Makefile system
59 <li>How to write a regression test
64 <li><a href="#coreclasses">The Core LLVM Class Hierarchy Reference</a>
66 <li><a href="#Value">The <tt>Value</tt> class</a>
68 <li><a href="#User">The <tt>User</tt> class</a>
70 <li><a href="#Instruction">The <tt>Instruction</tt> class</a>
75 <li><a href="#GlobalValue">The <tt>GlobalValue</tt> class</a>
77 <li><a href="#BasicBlock">The <tt>BasicBlock</tt> class</a>
78 <li><a href="#Function">The <tt>Function</tt> class</a>
79 <li><a href="#GlobalVariable">The <tt>GlobalVariable</tt> class</a>
81 <li><a href="#Module">The <tt>Module</tt> class</a>
82 <li><a href="#Constant">The <tt>Constant</tt> class</a>
88 <li><a href="#Type">The <tt>Type</tt> class</a>
89 <li><a href="#Argument">The <tt>Argument</tt> class</a>
91 <li>The <tt>SymbolTable</tt> class
92 <li>The <tt>ilist</tt> and <tt>iplist</tt> classes
94 <li>Creating, inserting, moving and deleting from LLVM lists
96 <li>Important iterator invalidation semantics to be aware of
99 <p><b>Written by <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a>
100 <a href="mailto:sabre@nondot.org">Chris Lattner</a>, and
101 <a href="mailto:jstanley@cs.uiuc.edu">Joel Stanley</a></b><p>
105 <!-- *********************************************************************** -->
106 <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
107 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
108 <a name="introduction">Introduction
109 </b></font></td></tr></table><ul>
110 <!-- *********************************************************************** -->
112 This document is meant to highlight some of the important classes and interfaces
113 available in the LLVM source-base. This manual is not intended to explain what
114 LLVM is, how it works, and what LLVM code looks like. It assumes that you know
115 the basics of LLVM and are interested in writing transformations or otherwise
116 analyzing or manipulating the code.<p>
118 This document should get you oriented so that you can find your way in the
119 continuously growing source code that makes up the LLVM infrastructure. Note
120 that this manual is not intended to serve as a replacement for reading the
121 source code, so if you think there should be a method in one of these classes to
122 do something, but it's not listed, check the source. Links to the <a
123 href="/doxygen/">doxygen</a> sources are provided to make this as easy as
126 The first section of this document describes general information that is useful
127 to know when working in the LLVM infrastructure, and the second describes the
128 Core LLVM classes. In the future this manual will be extended with information
129 describing how to use extension libraries, such as dominator information, CFG
130 traversal routines, and useful utilities like the <tt><a
131 href="/doxygen/InstVisitor_8h-source.html">InstVisitor</a></tt> template.<p>
134 <!-- *********************************************************************** -->
135 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
136 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
137 <a name="general">General Information
138 </b></font></td></tr></table><ul>
139 <!-- *********************************************************************** -->
141 This section contains general information that is useful if you are working in
142 the LLVM source-base, but that isn't specific to any particular API.<p>
145 <!-- ======================================================================= -->
146 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
147 <tr><td> </td><td width="100%">
148 <font color="#EEEEFF" face="Georgia,Palatino"><b>
149 <a name="stl">The C++ Standard Template Library</a>
150 </b></font></td></tr></table><ul>
152 LLVM makes heavy use of the C++ Standard Template Library (STL), perhaps much
153 more than you are used to, or have seen before. Because of this, you might want
154 to do a little background reading in the techniques used and capabilities of the
155 library. There are many good pages that discuss the STL, and several books on
156 the subject that you can get, so it will not be discussed in this document.<p>
158 Here are some useful links:<p>
160 <li><a href="http://www.dinkumware.com/htm_cpl/index.html">Dinkumware C++
161 Library reference</a> - an excellent reference for the STL and other parts of
162 the standard C++ library.<br>
164 <li><a href="http://www.parashift.com/c++-faq-lite/">C++ Frequently Asked
167 <li><a href="http://www.sgi.com/tech/stl/">SGI's STL Programmer's Guide</a> -
169 href="http://www.sgi.com/tech/stl/stl_introduction.html">Introduction to the
172 <li><a href="http://www.research.att.com/~bs/C++.html">Bjarne Stroustrup's C++
177 You are also encouraged to take a look at the <a
178 href="CodingStandards.html">LLVM Coding Standards</a> guide which focuses on how
179 to write maintainable code more than where to put your curly braces.<p>
183 <!-- *********************************************************************** -->
184 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
185 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
186 <a name="common">Helpful Hints for Common Operations
187 </b></font></td></tr></table><ul>
188 <!-- *********************************************************************** -->
190 This section describes how to perform some very simple transformations of LLVM
191 code. This is meant to give examples of common idioms used, showing the
192 practical side of LLVM transformations.<p>
194 Because this is a "how-to" section, you should also read about the main classes
195 that you will be working with. The <a href="#coreclasses">Core LLVM Class
196 Hierarchy Reference</a> contains details and descriptions of the main classes
197 that you should know about.<p>
199 <!-- NOTE: this section should be heavy on example code -->
202 <!-- ======================================================================= -->
203 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
204 <tr><td> </td><td width="100%">
205 <font color="#EEEEFF" face="Georgia,Palatino"><b>
206 <a name="inspection">Basic Inspection and Traversal Routines</a>
207 </b></font></td></tr></table><ul>
210 <!-- LLVM has heirarchical representation: Module, Function, BasicBlock,
211 Instruction. Common patterns for all levels. -->
213 <!-- _______________________________________________________________________ -->
214 </ul><h4><a name="iterate_function"><hr size=0>Iterating over the
215 <tt>BasicBlock</tt>s in a <tt>Function</tt> </h4><ul>
217 It's quite common to have a <tt>Function</tt> instance that you'd like
218 to transform in some way; in particular, you'd like to manipulate its
219 <tt>BasicBlock</tt>s. To facilitate this, you'll need to iterate over
220 all of the <tt>BasicBlock</tt>s that constitute the <tt>Function</tt>.
221 The following is an example that prints the name of a
222 <tt>BasicBlock</tt> and the number of <tt>Instruction</tt>s it
226 // func is a pointer to a Function instance
227 for(Function::iterator i = func->begin(), e = func->end(); i != e; ++i) {
229 // print out the name of the basic block if it has one, and then the
230 // number of instructions that it contains
232 cerr << "Basic block (name=" << i->getName() << ") has "
233 << i->size() << " instructions.\n";
237 Note that i can be used as if it were a pointer for the purposes of
238 invoking member functions of the <tt>Instruction</tt> class. This is
239 because the indirection operator is overloaded for the iterator
240 classes. In the above code, the expression <tt>i->size()</tt> is
241 exactly equivalent to <tt>(*i).size()</tt> just like you'd expect.
243 <!-- _______________________________________________________________________ -->
244 </ul><h4><a name="iterate_basicblock"><hr size=0>Iterating over the
245 <tt>Instruction</tt>s in a <tt>BasicBlock</tt> </h4><ul>
247 Just like when dealing with <tt>BasicBlock</tt>s in <tt>Function</tt>s, it's
248 easy to iterate over the individual instructions that make up
249 <tt>BasicBlock</tt>s. Here's a code snippet that prints out each instruction in
250 a <tt>BasicBlock</tt>:
253 // blk is a pointer to a BasicBlock instance
254 for(BasicBlock::iterator i = blk->begin(), e = blk->end(); i != e; ++i) {
255 // the next statement works since operator<<(ostream&,...)
256 // is overloaded for Instruction&
258 cerr << *i << endl;
262 However, this isn't really the best way to print out the contents of a
263 <tt>BasicBlock</tt>! Since the ostream operators are overloaded for
264 virtually anything you'll care about, you could have just invoked the
265 print routine on the basic block itself: <tt>cerr << *blk <<
268 Note that currently operator<< is implemented for <tt>Value*</tt>, so it
269 will print out the contents of the pointer, instead of
270 the pointer value you might expect. This is a deprecated interface that will
271 be removed in the future, so it's best not to depend on it. To print out the
272 pointer value for now, you must cast to <tt>void*</tt>.<p>
274 <!-- _______________________________________________________________________ -->
275 </ul><h4><a name="iterate_convert"><hr size=0>Turning an iterator into a class
278 Sometimes, it'll be useful to grab a reference (or pointer) to a class
279 instance when all you've got at hand is an iterator. Well, extracting
280 a reference or a pointer from an iterator is very straightforward.
281 Assuming that <tt>i</tt> is a <tt>BasicBlock::iterator</tt> and
282 <tt>j</tt> is a <tt>BasicBlock::const_iterator</tt>:
285 Instruction& inst = *i; // grab reference to instruction reference
286 Instruction* pinst = &*i; // grab pointer to instruction reference
287 const Instruction& inst = *j;
289 However, the iterators you'll be working with in the LLVM framework
290 are special: they will automatically convert to a ptr-to-instance type
291 whenever they need to. Instead of dereferencing the iterator and then
292 taking the address of the result, you can simply assign the iterator
293 to the proper pointer type and you get the dereference and address-of
294 operation as a result of the assignment (behind the scenes, this is a
295 result of overloading casting mechanisms). Thus the last line of the
298 <pre>Instruction* pinst = &*i;</pre>
300 is semantically equivalent to
302 <pre>Instruction* pinst = i;</pre>
304 <b>Caveat emptor</b>: The above syntax works <i>only</i> when you're
305 <i>not</i> working with <tt>dyn_cast</tt>. The template definition of
306 <tt>dyn_cast</tt> isn't implemented to handle this yet, so you'll
307 still need the following in order for things to work properly:
310 BasicBlock::iterator bbi = ...;
311 BranchInst* b = dyn_cast<BranchInst>(&*bbi);
314 The following code snippet illustrates use of the conversion
315 constructors provided by LLVM iterators. By using these, you can
316 explicitly grab the iterator of something without actually obtaining
317 it via iteration over some structure:
320 void printNextInstruction(Instruction* inst) {
321 BasicBlock::iterator it(inst);
322 ++it; // after this line, it refers to the instruction after *inst.
323 if(it != inst->getParent()->end()) cerr << *it << endl;
327 Of course, this example is strictly pedagogical, because it'd be
328 better to do something like
330 <pre>if(inst->getNext()) cerr << inst->getNext() << endl;</pre>
333 <!-- dereferenced iterator = Class &
334 iterators have converting constructor for 'Class *'
335 iterators automatically convert to 'Class *' except in dyn_cast<> case
339 _______________________________________________________________________
340 --> </ul><h4><a name="iterate_complex"><hr size=0>Finding call sites:
341 a slightly more complex example
344 Say that you're writing a FunctionPass and would like to count all the
345 locations in the entire module (that is, across every <tt>Function</tt>)
346 where a certain function named foo (that takes an int and returns an
347 int) is called. As you'll learn later, you may want to use an
348 <tt>InstVisitor</tt> to accomplish this in a much more straightforward
349 manner, but this example will allow us to explore how you'd do it if
350 you didn't have <tt>InstVisitor</tt> around. In pseudocode, this is
354 initialize callCounter to zero
355 for each Function f in the Module
356 for each BasicBlock b in f
357 for each Instruction i in b
358 if(i is a CallInst and foo is the function it calls)
359 increment callCounter
362 And the actual code is (remember, since we're writing a
363 <tt>FunctionPass</tt> our <tt>FunctionPass</tt>-derived class simply
364 has to override the <tt>runOnFunction</tt> method...):
368 // Assume callCounter is a private member of the pass class being written,
369 // and has been initialized in the pass class constructor.
371 virtual runOnFunction(Function& F) {
373 // Remember, we assumed that the signature of foo was "int foo(int)";
374 // the first thing we'll do is grab the pointer to that function (as a
375 // Function*) so we can use it later when we're examining the
376 // parameters of a CallInst. All of the code before the call to
377 // Module::getOrInsertFunction() is in preparation to do symbol-table
378 // to find the function pointer.
380 vector<const Type*> params;
381 params.push_back(Type::IntTy);
382 const FunctionType* fooType = FunctionType::get(Type::IntTy, params);
383 Function* foo = F.getParent()->getOrInsertFunction("foo", fooType);
385 // Start iterating and (as per the pseudocode), increment callCounter.
387 for(Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
388 for(BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {
389 if(CallInst* callInst = dyn_cast<CallInst>(&*inst)) {
390 // we know we've encountered a call instruction, so we
391 // need to determine if it's a call to foo or not
393 if(callInst->getCalledFunction() == foo)
401 We could then print out the value of callCounter (if we wanted to)
402 inside the doFinalization method of our FunctionPass.
405 <!-- ======================================================================= -->
406 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
407 <tr><td> </td><td width="100%">
408 <font color="#EEEEFF" face="Georgia,Palatino"><b>
409 <a name="simplechanges">Making simple changes</a>
410 </b></font></td></tr></table><ul>
412 <!-- Value::replaceAllUsesWith
413 User::replaceUsesOfWith
414 Point out: include/llvm/Transforms/Utils/
415 especially BasicBlockUtils.h with:
416 ReplaceInstWithValue, ReplaceInstWithInst
421 <!-- *********************************************************************** -->
422 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
423 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
424 <a name="coreclasses">The Core LLVM Class Hierarchy Reference
425 </b></font></td></tr></table><ul>
426 <!-- *********************************************************************** -->
428 The Core LLVM classes are the primary means of representing the program being
429 inspected or transformed. The core LLVM classes are defined in header files in
430 the <tt>include/llvm/</tt> directory, and implemented in the <tt>lib/VMCore</tt>
434 <!-- ======================================================================= -->
435 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
436 <tr><td> </td><td width="100%">
437 <font color="#EEEEFF" face="Georgia,Palatino"><b>
438 <a name="Value">The <tt>Value</tt> class</a>
439 </b></font></td></tr></table><ul>
441 <tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt></b><br>
442 doxygen info: <a href="/doxygen/classValue.html">Value Class</a><p>
445 The <tt>Value</tt> class is the most important class in LLVM Source base. It
446 represents a typed value that may be used (among other things) as an operand to
447 an instruction. There are many different types of <tt>Value</tt>s, such as <a
448 href="#Constant"><tt>Constant</tt></a>s, <a
449 href="#Argument"><tt>Argument</tt></a>s, and even <a
450 href="#Instruction"><tt>Instruction</tt></a>s and <a
451 href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.<p>
453 A particular <tt>Value</tt> may be used many times in the LLVM representation
454 for a program. For example, an incoming argument to a function (represented
455 with an instance of the <a href="#Argument">Argument</a> class) is "used" by
456 every instruction in the function that references the argument. To keep track
457 of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
458 href="#User"><tt>User</tt></a>s that is using it (the <a
459 href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
460 graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
461 def-use information in the program, and is accessible through the <tt>use_</tt>*
462 methods, shown below.<p>
464 Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed, and
465 this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
466 method. <a name="#nameWarning">In addition, all LLVM values can be named. The
467 "name" of the <tt>Value</tt> is symbolic string printed in the LLVM code:<p>
470 %<b>foo</b> = add int 1, 2
473 The name of this instruction is "foo". <b>NOTE</b> that the name of any value
474 may be missing (an empty string), so names should <b>ONLY</b> be used for
475 debugging (making the source code easier to read, debugging printouts), they
476 should not be used to keep track of values or map between them. For this
477 purpose, use a <tt>std::map</tt> of pointers to the <tt>Value</tt> itself
480 One important aspect of LLVM is that there is no distinction between an SSA
481 variable and the operation that produces it. Because of this, any reference to
482 the value produced by an instruction (or the value available as an incoming
483 argument, for example) is represented as a direct pointer to the class that
484 represents this value. Although this may take some getting used to, it
485 simplifies the representation and makes it easier to manipulate.<p>
488 <!-- _______________________________________________________________________ -->
489 </ul><h4><a name="m_Value"><hr size=0>Important Public Members of
490 the <tt>Value</tt> class</h4><ul>
492 <li><tt>Value::use_iterator</tt> - Typedef for iterator over the use-list<br>
493 <tt>Value::use_const_iterator</tt>
494 - Typedef for const_iterator over the use-list<br>
495 <tt>unsigned use_size()</tt> - Returns the number of users of the value.<br>
496 <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
497 <tt>use_iterator use_begin()</tt>
498 - Get an iterator to the start of the use-list.<br>
499 <tt>use_iterator use_end()</tt>
500 - Get an iterator to the end of the use-list.<br>
501 <tt><a href="#User">User</a> *use_back()</tt>
502 - Returns the last element in the list.<p>
504 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>
506 <li><tt><a href="#Type">Type</a> *getType() const</tt><p>
507 This method returns the Type of the Value.
509 <li><tt>bool hasName() const</tt><br>
510 <tt>std::string getName() const</tt><br>
511 <tt>void setName(const std::string &Name)</tt><p>
513 This family of methods is used to access and assign a name to a <tt>Value</tt>,
514 be aware of the <a href="#nameWarning">precaution above</a>.<p>
517 <li><tt>void replaceAllUsesWith(Value *V)</tt><p>
519 This method traverses the use list of a <tt>Value</tt> changing all <a
520 href="#User"><tt>User</tt>'s</a> of the current value to refer to "<tt>V</tt>"
521 instead. For example, if you detect that an instruction always produces a
522 constant value (for example through constant folding), you can replace all uses
523 of the instruction with the constant like this:<p>
526 Inst->replaceAllUsesWith(ConstVal);
531 <!-- ======================================================================= -->
532 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
533 <tr><td> </td><td width="100%">
534 <font color="#EEEEFF" face="Georgia,Palatino"><b>
535 <a name="User">The <tt>User</tt> class</a>
536 </b></font></td></tr></table><ul>
538 <tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt></b><br>
539 doxygen info: <a href="/doxygen/classUser.html">User Class</a><br>
540 Superclass: <a href="#Value"><tt>Value</tt></a><p>
543 The <tt>User</tt> class is the common base class of all LLVM nodes that may
544 refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
545 that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
546 referring to. The <tt>User</tt> class itself is a subclass of
549 The operands of a <tt>User</tt> point directly to the LLVM <a
550 href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
551 Single Assignment (SSA) form, there can only be one definition referred to,
552 allowing this direct connection. This connection provides the use-def
553 information in LLVM.<p>
555 <!-- _______________________________________________________________________ -->
556 </ul><h4><a name="m_User"><hr size=0>Important Public Members of
557 the <tt>User</tt> class</h4><ul>
559 The <tt>User</tt> class exposes the operand list in two ways: through an index
560 access interface and through an iterator based interface.<p>
562 <li><tt>Value *getOperand(unsigned i)</tt><br>
563 <tt>unsigned getNumOperands()</tt><p>
565 These two methods expose the operands of the <tt>User</tt> in a convenient form
566 for direct access.<p>
568 <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand list<br>
569 <tt>User::op_const_iterator</tt>
570 <tt>use_iterator op_begin()</tt>
571 - Get an iterator to the start of the operand list.<br>
572 <tt>use_iterator op_end()</tt>
573 - Get an iterator to the end of the operand list.<p>
575 Together, these methods make up the iterator based interface to the operands of
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="Instruction">The <tt>Instruction</tt> class</a>
585 </b></font></td></tr></table><ul>
588 href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt></b><br>
589 doxygen info: <a href="/doxygen/classInstruction.html">Instruction Class</a><br>
590 Superclasses: <a href="#User"><tt>User</tt></a>, <a
591 href="#Value"><tt>Value</tt></a><p>
593 The <tt>Instruction</tt> class is the common base class for all LLVM
594 instructions. It provides only a few methods, but is a very commonly used
595 class. The primary data tracked by the <tt>Instruction</tt> class itself is the
596 opcode (instruction type) and the parent <a
597 href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
598 into. To represent a specific type of instruction, one of many subclasses of
599 <tt>Instruction</tt> are used.<p>
601 Because the <tt>Instruction</tt> class subclasses the <a
602 href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
603 way as for other <a href="#User"><tt>User</tt></a>s (with the
604 <tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
605 <tt>op_begin()</tt>/<tt>op_end()</tt> methods).<p>
608 <!-- _______________________________________________________________________ -->
609 </ul><h4><a name="m_Instruction"><hr size=0>Important Public Members of
610 the <tt>Instruction</tt> class</h4><ul>
612 <li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt><p>
614 Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that this
615 <tt>Instruction</tt> is embedded into.<p>
617 <li><tt>bool hasSideEffects()</tt><p>
619 Returns true if the instruction has side effects, i.e. it is a <tt>call</tt>,
620 <tt>free</tt>, <tt>invoke</tt>, or <tt>store</tt>.<p>
622 <li><tt>unsigned getOpcode()</tt><p>
624 Returns the opcode for the <tt>Instruction</tt>.<p>
628 \subsection{Subclasses of Instruction :}
630 <li>BinaryOperator : This subclass of Instruction defines a general interface to the all the instructions involvong binary operators in LLVM.
632 <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.
634 <li>TerminatorInst : This subclass of Instructions defines an interface for all instructions that can terminate a BasicBlock.
636 <li> <tt>unsigned getNumSuccessors()</tt>: Returns the number of successors for this terminator instruction.
637 <li><tt>BasicBlock *getSuccessor(unsigned i)</tt>: As the name suggests returns the ith successor BasicBlock.
638 <li><tt>void setSuccessor(unsigned i, BasicBlock *B)</tt>: sets BasicBlock B as the ith succesor to this terminator instruction.
641 <li>PHINode : This represents the PHI instructions in the SSA form.
643 <li><tt> unsigned getNumIncomingValues()</tt>: Returns the number of incoming edges to this PHI node.
644 <li><tt> Value *getIncomingValue(unsigned i)</tt>: Returns the ith incoming Value.
645 <li><tt>void setIncomingValue(unsigned i, Value *V)</tt>: Sets the ith incoming Value as V
646 <li><tt>BasicBlock *getIncomingBlock(unsigned i)</tt>: Returns the Basic Block corresponding to the ith incoming Value.
647 <li><tt> void addIncoming(Value *D, BasicBlock *BB)</tt>:
648 Add an incoming value to the end of the PHI list
649 <li><tt> int getBasicBlockIndex(const BasicBlock *BB) const</tt>:
650 Returns the first index of the specified basic block in the value list for this PHI. Returns -1 if no instance.
652 <li>CastInst : In LLVM all casts have to be done through explicit cast instructions. CastInst defines the interface to the cast instructions.
653 <li>CallInst : This defines an interface to the call instruction in LLVM. ARguments to the function are nothing but operands of the instruction.
655 <li>: <tt>Function *getCalledFunction()</tt>: Returns a handle to the function that is being called by this Function.
657 <li>LoadInst, StoreInst, GetElemPtrInst : These subclasses represent load, store and getelementptr instructions in LLVM.
659 <li><tt>Value * getPointerOperand ()</tt>: Returns the Pointer Operand which is typically the 0th operand.
661 <li>BranchInst : This is a subclass of TerminatorInst and defines the interface for conditional and unconditional branches in LLVM.
663 <li><tt>bool isConditional()</tt>: Returns true if the branch is a conditional branch else returns false
664 <li> <tt>Value *getCondition()</tt>: Returns the condition if it is a conditional branch else returns null.
665 <li> <tt>void setUnconditionalDest(BasicBlock *Dest)</tt>: Changes the current branch to an unconditional one targetting the specified block.
673 <!-- ======================================================================= -->
674 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
675 <tr><td> </td><td width="100%">
676 <font color="#EEEEFF" face="Georgia,Palatino"><b>
677 <a name="BasicBlock">The <tt>BasicBlock</tt> class</a>
678 </b></font></td></tr></table><ul>
681 href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt></b><br>
682 doxygen info: <a href="/doxygen/classBasicBlock.html">BasicBlock Class</a><br>
683 Superclass: <a href="#Value"><tt>Value</tt></a><p>
686 This class represents a single entry multiple exit section of the code, commonly
687 known as a basic block by the compiler community. The <tt>BasicBlock</tt> class
688 maintains a list of <a href="#Instruction"><tt>Instruction</tt></a>s, which form
689 the body of the block. Matching the language definition, the last element of
690 this list of instructions is always a terminator instruction (a subclass of the
691 <a href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).<p>
693 In addition to tracking the list of instructions that make up the block, the
694 <tt>BasicBlock</tt> class also keeps track of the <a
695 href="#Function"><tt>Function</tt></a> that it is embedded into.<p>
697 Note that <tt>BasicBlock</tt>s themselves are <a
698 href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
699 like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
703 <!-- _______________________________________________________________________ -->
704 </ul><h4><a name="m_BasicBlock"><hr size=0>Important Public Members of
705 the <tt>BasicBlock</tt> class</h4><ul>
707 <li><tt>BasicBlock(const std::string &Name = "", <a
708 href="#Function">Function</a> *Parent = 0)</tt><p>
710 The <tt>BasicBlock</tt> constructor is used to create new basic blocks for
711 insertion into a function. The constructor simply takes a name for the new
712 block, and optionally a <a href="#Function"><tt>Function</tt></a> to insert it
713 into. If the <tt>Parent</tt> parameter is specified, the new
714 <tt>BasicBlock</tt> is automatically inserted at the end of the specified <a
715 href="#Function"><tt>Function</tt></a>, if not specified, the BasicBlock must be
716 manually inserted into the <a href="#Function"><tt>Function</tt></a>.<p>
718 <li><tt>BasicBlock::iterator</tt> - Typedef for instruction list iterator<br>
719 <tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
720 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
721 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
723 These methods and typedefs are forwarding functions that have the same semantics
724 as the standard library methods of the same names. These methods expose the
725 underlying instruction list of a basic block in a way that is easy to
726 manipulate. To get the full complement of container operations (including
727 operations to update the list), you must use the <tt>getInstList()</tt>
730 <li><tt>BasicBlock::InstListType &getInstList()</tt><p>
732 This method is used to get access to the underlying container that actually
733 holds the Instructions. This method must be used when there isn't a forwarding
734 function in the <tt>BasicBlock</tt> class for the operation that you would like
735 to perform. Because there are no forwarding functions for "updating"
736 operations, you need to use this if you want to update the contents of a
737 <tt>BasicBlock</tt>.<p>
739 <li><tt><A href="#Function">Function</a> *getParent()</tt><p>
741 Returns a pointer to <a href="#Function"><tt>Function</tt></a> the block is
742 embedded into, or a null pointer if it is homeless.<p>
744 <li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt><p>
746 Returns a pointer to the terminator instruction that appears at the end of the
747 <tt>BasicBlock</tt>. If there is no terminator instruction, or if the last
748 instruction in the block is not a terminator, then a null pointer is
752 <!-- ======================================================================= -->
753 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
754 <tr><td> </td><td width="100%">
755 <font color="#EEEEFF" face="Georgia,Palatino"><b>
756 <a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
757 </b></font></td></tr></table><ul>
760 href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt></b><br>
761 doxygen info: <a href="/doxygen/classGlobalValue.html">GlobalValue Class</a><br>
762 Superclasses: <a href="#User"><tt>User</tt></a>, <a
763 href="#Value"><tt>Value</tt></a><p>
765 Global values (<A href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
766 href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
767 visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
768 Because they are visible at global scope, they are also subject to linking with
769 other globals defined in different translation units. To control the linking
770 process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
771 <tt>GlobalValue</tt>s know whether they have internal or external linkage.<p>
773 If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
774 <tt>static</tt> in C), it is not visible to code outside the current translation
775 unit, and does not participate in linking. If it has external linkage, it is
776 visible to external code, and does participate in linking. In addition to
777 linkage information, <tt>GlobalValue</tt>s keep track of which <a
778 href="#Module"><tt>Module</tt></a> they are currently part of.<p>
780 Because <tt>GlobalValue</tt>s are memory objects, they are always referred to by
781 their address. As such, the <a href="#Type"><tt>Type</tt></a> of a global is
782 always a pointer to its contents. This is explained in the LLVM Language
786 <!-- _______________________________________________________________________ -->
787 </ul><h4><a name="m_GlobalValue"><hr size=0>Important Public Members of
788 the <tt>GlobalValue</tt> class</h4><ul>
790 <li><tt>bool hasInternalLinkage() const</tt><br>
791 <tt>bool hasExternalLinkage() const</tt><br>
792 <tt>void setInternalLinkage(bool HasInternalLinkage)</tt><p>
794 These methods manipulate the linkage characteristics of the
795 <tt>GlobalValue</tt>.<p>
797 <li><tt><a href="#Module">Module</a> *getParent()</tt><p>
799 This returns the <a href="#Module"><tt>Module</tt></a> that the GlobalValue is
800 currently embedded into.<p>
804 <!-- ======================================================================= -->
805 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
806 <tr><td> </td><td width="100%">
807 <font color="#EEEEFF" face="Georgia,Palatino"><b>
808 <a name="Function">The <tt>Function</tt> class</a>
809 </b></font></td></tr></table><ul>
812 href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt></b><br>
813 doxygen info: <a href="/doxygen/classFunction.html">Function Class</a><br>
814 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
815 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
817 The <tt>Function</tt> class represents a single procedure in LLVM. It is
818 actually one of the more complex classes in the LLVM heirarchy because it must
819 keep track of a large amount of data. The <tt>Function</tt> class keeps track
820 of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
821 href="#Argument"><tt>Argument</tt></a>s, and a <a
822 href="#SymbolTable"><tt>SymbolTable</tt></a>.<p>
824 The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most commonly
825 used part of <tt>Function</tt> objects. The list imposes an implicit ordering
826 of the blocks in the function, which indicate how the code will be layed out by
827 the backend. Additionally, the first <a
828 href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
829 <tt>Function</tt>. It is not legal in LLVM explicitly branch to this initial
830 block. There are no implicit exit nodes, and in fact there may be multiple exit
831 nodes from a single <tt>Function</tt>. If the <a
832 href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
833 the <tt>Function</tt> is actually a function declaration: the actual body of the
834 function hasn't been linked in yet.<p>
836 In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
837 <tt>Function</tt> class also keeps track of the list of formal <a
838 href="#Argument"><tt>Argument</tt></a>s that the function receives. This
839 container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
840 nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
841 the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.<p>
843 The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used LLVM
844 feature that is only used when you have to look up a value by name. Aside from
845 that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used internally to
846 make sure that there are not conflicts between the names of <a
847 href="#Instruction"><tt>Instruction</tt></a>s, <a
848 href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
849 href="#Argument"><tt>Argument</tt></a>s in the function body.<p>
852 <!-- _______________________________________________________________________ -->
853 </ul><h4><a name="m_Function"><hr size=0>Important Public Members of
854 the <tt>Function</tt> class</h4><ul>
856 <li><tt>Function(const <a href="#FunctionType">FunctionType</a> *Ty, bool isInternal, const std::string &N = "")</tt><p>
858 Constructor used when you need to create new <tt>Function</tt>s to add the the
859 program. The constructor must specify the type of the function to create and
860 whether or not it should start out with internal or external linkage.<p>
862 <li><tt>bool isExternal()</tt><p>
864 Return whether or not the <tt>Function</tt> has a body defined. If the function
865 is "external", it does not have a body, and thus must be resolved by linking
866 with a function defined in a different translation unit.<p>
869 <li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
870 <tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
871 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
872 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
874 These are forwarding methods that make it easy to access the contents of a
875 <tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
878 <li><tt>Function::BasicBlockListType &getBasicBlockList()</tt><p>
880 Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This is
881 neccesary to use when you need to update the list or perform a complex action
882 that doesn't have a forwarding method.<p>
885 <li><tt>Function::aiterator</tt> - Typedef for the argument list iterator<br>
886 <tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
887 <tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
888 <tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt><p>
890 These are forwarding methods that make it easy to access the contents of a
891 <tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a> list.<p>
893 <li><tt>Function::ArgumentListType &getArgumentList()</tt><p>
895 Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This is
896 neccesary to use when you need to update the list or perform a complex action
897 that doesn't have a forwarding method.<p>
901 <li><tt><a href="#BasicBlock">BasicBlock</a> &getEntryNode()</tt><p>
903 Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
904 function. Because the entry block for the function is always the first block,
905 this returns the first block of the <tt>Function</tt>.<p>
907 <li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
908 <tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt><p>
910 This traverses the <a href="#Type"><tt>Type</tt></a> of the <tt>Function</tt>
911 and returns the return type of the function, or the <a
912 href="#FunctionType"><tt>FunctionType</tt></a> of the actual function.<p>
915 <li><tt>bool hasSymbolTable() const</tt><p>
917 Return true if the <tt>Function</tt> has a symbol table allocated to it and if
918 there is at least one entry in it.<p>
920 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
922 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
923 <tt>Function</tt> or a null pointer if one has not been allocated (because there
924 are no named values in the function).<p>
926 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
928 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
929 <tt>Function</tt> or allocate a new <a
930 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
931 should only be used when adding elements to the <a
932 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
933 not left laying around.<p>
937 <!-- ======================================================================= -->
938 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
939 <tr><td> </td><td width="100%">
940 <font color="#EEEEFF" face="Georgia,Palatino"><b>
941 <a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
942 </b></font></td></tr></table><ul>
945 href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt></b><br>
946 doxygen info: <a href="/doxygen/classGlobalVariable.html">GlobalVariable Class</a><br>
947 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
948 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
950 Global variables are represented with the (suprise suprise)
951 <tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are
952 also subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such
953 are always referenced by their address (global values must live in memory, so
954 their "name" refers to their address). Global variables may have an initial
955 value (which must be a <a href="#Constant"><tt>Constant</tt></a>), and if they
956 have an initializer, they may be marked as "constant" themselves (indicating
957 that their contents never change at runtime).<p>
960 <!-- _______________________________________________________________________ -->
961 </ul><h4><a name="m_GlobalVariable"><hr size=0>Important Public Members of the
962 <tt>GlobalVariable</tt> class</h4><ul>
964 <li><tt>GlobalVariable(const <a href="#Type">Type</a> *Ty, bool isConstant, bool
965 isInternal, <a href="#Constant">Constant</a> *Initializer = 0, const std::string
966 &Name = "")</tt><p>
968 Create a new global variable of the specified type. If <tt>isConstant</tt> is
969 true then the global variable will be marked as unchanging for the program, and
970 if <tt>isInternal</tt> is true the resultant global variable will have internal
971 linkage. Optionally an initializer and name may be specified for the global variable as well.<p>
974 <li><tt>bool isConstant() const</tt><p>
976 Returns true if this is a global variable is known not to be modified at
980 <li><tt>bool hasInitializer()</tt><p>
982 Returns true if this <tt>GlobalVariable</tt> has an intializer.<p>
985 <li><tt><a href="#Constant">Constant</a> *getInitializer()</tt><p>
987 Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal to call
988 this method if there is no initializer.<p>
991 <!-- ======================================================================= -->
992 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
993 <tr><td> </td><td width="100%">
994 <font color="#EEEEFF" face="Georgia,Palatino"><b>
995 <a name="Module">The <tt>Module</tt> class</a>
996 </b></font></td></tr></table><ul>
999 href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt></b><br>
1000 doxygen info: <a href="/doxygen/classModule.html">Module Class</a><p>
1002 The <tt>Module</tt> class represents the top level structure present in LLVM
1003 programs. An LLVM module is effectively either a translation unit of the
1004 original program or a combination of several translation units merged by the
1005 linker. The <tt>Module</tt> class keeps track of a list of <a
1006 href="#Function"><tt>Function</tt></a>s, a list of <a
1007 href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
1008 href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
1009 helpful member functions that try to make common operations easy.<p>
1012 <!-- _______________________________________________________________________ -->
1013 </ul><h4><a name="m_Module"><hr size=0>Important Public Members of the
1014 <tt>Module</tt> class</h4><ul>
1016 <li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
1017 <tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
1018 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
1019 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
1021 These are forwarding methods that make it easy to access the contents of a
1022 <tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
1025 <li><tt>Module::FunctionListType &getFunctionList()</tt><p>
1027 Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
1028 neccesary to use when you need to update the list or perform a complex action
1029 that doesn't have a forwarding method.<p>
1031 <!-- Global Variable -->
1034 <li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
1035 <tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
1036 <tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
1037 <tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt><p>
1039 These are forwarding methods that make it easy to access the contents of a
1040 <tt>Module</tt> object's <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>
1043 <li><tt>Module::GlobalListType &getGlobalList()</tt><p>
1045 Returns the list of <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s.
1046 This is neccesary to use when you need to update the list or perform a complex
1047 action that doesn't have a forwarding method.<p>
1050 <!-- Symbol table stuff -->
1053 <li><tt>bool hasSymbolTable() const</tt><p>
1055 Return true if the <tt>Module</tt> has a symbol table allocated to it and if
1056 there is at least one entry in it.<p>
1058 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
1060 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1061 <tt>Module</tt> or a null pointer if one has not been allocated (because there
1062 are no named values in the function).<p>
1064 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
1066 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1067 <tt>Module</tt> or allocate a new <a
1068 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
1069 should only be used when adding elements to the <a
1070 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
1071 not left laying around.<p>
1074 <!-- Convenience methods -->
1077 <li><tt><a href="#Function">Function</a> *getFunction(const std::string &Name, const <a href="#FunctionType">FunctionType</a> *Ty)</tt><p>
1079 Look up the specified function in the <tt>Module</tt> <a
1080 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
1084 <li><tt><a href="#Function">Function</a> *getOrInsertFunction(const std::string
1085 &Name, const <a href="#FunctionType">FunctionType</a> *T)</tt><p>
1087 Look up the specified function in the <tt>Module</tt> <a
1088 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, add an
1089 external declaration for the function and return it.<p>
1092 <li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt><p>
1094 If there is at least one entry in the <a
1095 href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
1096 href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
1100 <li><tt>bool addTypeName(const std::string &Name, const <a href="#Type">Type</a>
1103 Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a> mapping
1104 <tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this name, true
1105 is returned and the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is not
1109 <!-- ======================================================================= -->
1110 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1111 <tr><td> </td><td width="100%">
1112 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1113 <a name="Constant">The <tt>Constant</tt> class and subclasses</a>
1114 </b></font></td></tr></table><ul>
1116 Constant represents a base class for different types of constants. It is
1117 subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
1118 ConstantArray etc for representing the various types of Constants.<p>
1121 <!-- _______________________________________________________________________ -->
1122 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1124 <li><tt>bool isConstantExpr()</tt>: Returns true if it is a ConstantExpr
1129 \subsection{Important Subclasses of Constant}
1131 <li>ConstantSInt : This subclass of Constant represents a signed integer constant.
1133 <li><tt>int64_t getValue () const</tt>: Returns the underlying value of this constant.
1135 <li>ConstantUInt : This class represents an unsigned integer.
1137 <li><tt>uint64_t getValue () const</tt>: Returns the underlying value of this constant.
1139 <li>ConstantFP : This class represents a floating point constant.
1141 <li><tt>double getValue () const</tt>: Returns the underlying value of this constant.
1143 <li>ConstantBool : This represents a boolean constant.
1145 <li><tt>bool getValue () const</tt>: Returns the underlying value of this constant.
1147 <li>ConstantArray : This represents a constant array.
1149 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1151 <li>ConstantStruct : This represents a constant struct.
1153 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1155 <li>ConstantPointerRef : This represents a constant pointer value that is initialized to point to a global value, which lies at a constant fixed address.
1157 <li><tt>GlobalValue *getValue()</tt>: Returns the global value to which this pointer is pointing to.
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="Type">The <tt>Type</tt> class and Derived Types</a>
1167 </b></font></td></tr></table><ul>
1169 Type as noted earlier is also a subclass of a Value class. Any primitive
1170 type (like int, short etc) in LLVM is an instance of Type Class. All
1171 other types are instances of subclasses of type like FunctionType,
1172 ArrayType etc. DerivedType is the interface for all such dervied types
1173 including FunctionType, ArrayType, PointerType, StructType. Types can have
1174 names. They can be recursive (StructType). There exists exactly one instance
1175 of any type structure at a time. This allows using pointer equality of Type *s for comparing types.
1177 <!-- _______________________________________________________________________ -->
1178 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1180 <li><tt>PrimitiveID getPrimitiveID () const</tt>: Returns the base type of the type.
1181 <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.
1182 <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.
1183 <li><tt> bool isInteger () const</tt>: Equilivent to isSigned() || isUnsigned(), but with only a single virtual function invocation.
1184 <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.
1186 <li><tt>bool isFloatingPoint ()</tt>: Return true if this is one of the two floating point types.
1187 <li><tt>bool isRecursive () const</tt>: Returns rue if the type graph contains a cycle.
1188 <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.
1189 <li><tt>bool isPrimitiveType () const</tt>: Returns true if it is a primitive type.
1190 <li><tt>bool isDerivedType () const</tt>: Returns true if it is a derived type.
1191 <li><tt>const Type * getContainedType (unsigned i) const</tt>:
1192 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.
1193 <li><tt>unsigned getNumContainedTypes () const</tt>: Return the number of types in the derived type.
1197 \subsection{Derived Types}
1199 <li>SequentialType : This is subclassed by ArrayType and PointerType
1201 <li><tt>const Type * getElementType () const</tt>: Returns the type of each of the elements in the sequential type.
1203 <li>ArrayType : This is a subclass of SequentialType and defines interface for array types.
1205 <li><tt>unsigned getNumElements () const</tt>: Returns the number of elements in the array.
1207 <li>PointerType : Subclass of SequentialType for pointer types.
1208 <li>StructType : subclass of DerivedTypes for struct types
1209 <li>FunctionType : subclass of DerivedTypes for function types.
1212 <li><tt>bool isVarArg () const</tt>: Returns true if its a vararg function
1213 <li><tt> const Type * getReturnType () const</tt>: Returns the return type of the function.
1214 <li><tt> const ParamTypes &getParamTypes () const</tt>: Returns a vector of parameter types.
1215 <li><tt>const Type * getParamType (unsigned i)</tt>: Returns the type of the ith parameter.
1216 <li><tt> const unsigned getNumParams () const</tt>: Returns the number of formal parameters.
1223 <!-- ======================================================================= -->
1224 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1225 <tr><td> </td><td width="100%">
1226 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1227 <a name="Argument">The <tt>Argument</tt> class</a>
1228 </b></font></td></tr></table><ul>
1230 This subclass of Value defines the interface for incoming formal arguments to a
1231 function. A Function maitanis a list of its formal arguments. An argument has a
1232 pointer to the parent Function.
1237 <!-- *********************************************************************** -->
1239 <!-- *********************************************************************** -->
1242 <address>By: <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
1243 <a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
1244 <!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
1245 <!-- hhmts start -->
1246 Last modified: Fri Sep 6 17:12:14 CDT 2002
1248 </font></body></html>