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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
248 <tt>Function</tt>s, it's easy to iterate over the individual
249 instructions that make up <tt>BasicBlock</tt>s. Here's a code snippet
250 that prints out each instruction in 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&
257 cerr << *i << endl;
260 However, this isn't really the best way to print out the contents of a
261 <tt>BasicBlock</tt>! Since the ostream operators are overloaded for
262 virtually anything you'll care about, you could have just invoked the
263 print routine on the basic block itself: <tt>cerr << *blk <<
266 Note that currently operator<< is implemented for <tt>Value*</tt>, so it
267 will print out the contents of the pointer, instead of
268 the pointer value you might expect. This is a deprecated interface that will
269 be removed in the future, so it's best not to depend on it. To print out the
270 pointer value for now, you must cast to <tt>void*</tt>.<p>
272 <!-- _______________________________________________________________________ -->
273 </ul><h4><a name="iterate_convert"><hr size=0>Turning an iterator into a class
276 Sometimes, it'll be useful to grab a reference (or pointer) to a class
277 instance when all you've got at hand is an iterator. Well, extracting
278 a reference or a pointer from an iterator is very straightforward.
279 Assuming that <tt>i</tt> is a <tt>BasicBlock::iterator</tt> and
280 <tt>j</tt> is a <tt>BasicBlock::const_iterator</tt>:
283 Instruction& inst = *i; // grab reference to instruction reference
284 Instruction* pinst = &*i; // grab pointer to instruction reference
285 const Instruction& inst = *j;
287 However, the iterators you'll be working with in the LLVM framework
288 are special: they will automatically convert to a ptr-to-instance type
289 whenever they need to. Instead of dereferencing the iterator and then
290 taking the address of the result, you can simply assign the iterator
291 to the proper pointer type and you get the dereference and address-of
292 operation as a result of the assignment (behind the scenes, this is a
293 result of overloading casting mechanisms). Thus the last line of the
296 <pre>Instruction* pinst = &*i;</pre>
298 is semantically equivalent to
300 <pre>Instruction* pinst = i;</pre>
302 <b>Caveat emptor</b>: The above syntax works <i>only</i> when you're
303 <i>not</i> working with <tt>dyn_cast</tt>. The template definition of
304 <tt>dyn_cast</tt> isn't implemented to handle this yet, so you'll
305 still need the following in order for things to work properly:
308 BasicBlock::iterator bbi = ...;
309 BranchInst* b = dyn_cast<BranchInst>(&*bbi);
312 The following code snippet illustrates use of the conversion
313 constructors provided by LLVM iterators. By using these, you can
314 explicitly grab the iterator of something without actually obtaining
315 it via iteration over some structure:
318 void printNextInstruction(Instruction* inst) {
319 BasicBlock::iterator it(inst);
320 ++it; // after this line, it refers to the instruction after *inst.
321 if(it != inst->getParent()->end()) cerr << *it << endl;
324 Of course, this example is strictly pedagogical, because it'd be much
325 better to explicitly grab the next instruction directly from inst.
327 <!-- dereferenced iterator = Class &
328 iterators have converting constructor for 'Class *'
329 iterators automatically convert to 'Class *' except in dyn_cast<> case
333 _______________________________________________________________________
334 --> </ul><h4><a name="iterate_complex"><hr size=0>Finding call sites:
335 a slightly more complex example
338 Say that you're writing a FunctionPass and would like to count all the
339 locations in the entire module (that is, across every <tt>Function</tt>)
340 where a certain function named foo (that takes an int and returns an
341 int) is called. As you'll learn later, you may want to use an
342 <tt>InstVisitor</tt> to accomplish this in a much more straightforward
343 manner, but this example will allow us to explore how you'd do it if
344 you didn't have <tt>InstVisitor</tt> around. In pseudocode, this is
348 initialize callCounter to zero
349 for each Function f in the Module
350 for each BasicBlock b in f
351 for each Instruction i in b
352 if(i is a CallInst and foo is the function it calls)
353 increment callCounter
356 And the actual code is (remember, since we're writing a
357 <tt>FunctionPass</tt> our <tt>FunctionPass</tt>-derived class simply
358 has to override the <tt>runOnFunction</tt> method...):
362 // Assume callCounter is a private member of the pass class being written,
363 // and has been initialized in the pass class constructor.
365 virtual runOnFunction(Function& F) {
367 // Remember, we assumed that the signature of foo was "int foo(int)";
368 // the first thing we'll do is grab the pointer to that function (as a
369 // Function*) so we can use it later when we're examining the
370 // parameters of a CallInst. All of the code before the call to
371 // Module::getOrInsertFunction() is in preparation to do symbol-table
372 // to find the function pointer.
374 vector<const Type*> params;
375 params.push_back(Type::IntTy);
376 const FunctionType* fooType = FunctionType::get(Type::IntTy, params);
377 Function* foo = F.getParent()->getOrInsertFunction("foo", fooType);
379 // Start iterating and (as per the pseudocode), increment callCounter.
381 for(Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
382 for(BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {
383 if(CallInst* callInst = dyn_cast<CallInst>(&*inst)) {
384 // we know we've encountered a call instruction, so we
385 // need to determine if it's a call to foo or not
387 if(callInst->getCalledFunction() == foo)
395 We could then print out the value of callCounter (if we wanted to)
396 inside the doFinalization method of our FunctionPass.
398 <!-- ======================================================================= -->
399 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
400 <tr><td> </td><td width="100%">
401 <font color="#EEEEFF" face="Georgia,Palatino"><b>
402 <a name="simplechanges">Making simple changes</a>
403 </b></font></td></tr></table><ul>
405 <!-- Value::replaceAllUsesWith
406 User::replaceUsesOfWith
407 Point out: include/llvm/Transforms/Utils/
408 especially BasicBlockUtils.h with:
409 ReplaceInstWithValue, ReplaceInstWithInst
414 <!-- *********************************************************************** -->
415 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
416 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
417 <a name="coreclasses">The Core LLVM Class Hierarchy Reference
418 </b></font></td></tr></table><ul>
419 <!-- *********************************************************************** -->
421 The Core LLVM classes are the primary means of representing the program being
422 inspected or transformed. The core LLVM classes are defined in header files in
423 the <tt>include/llvm/</tt> directory, and implemented in the <tt>lib/VMCore</tt>
427 <!-- ======================================================================= -->
428 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
429 <tr><td> </td><td width="100%">
430 <font color="#EEEEFF" face="Georgia,Palatino"><b>
431 <a name="Value">The <tt>Value</tt> class</a>
432 </b></font></td></tr></table><ul>
434 <tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt></b><br>
435 doxygen info: <a href="/doxygen/classValue.html">Value Class</a><p>
438 The <tt>Value</tt> class is the most important class in LLVM Source base. It
439 represents a typed value that may be used (among other things) as an operand to
440 an instruction. There are many different types of <tt>Value</tt>s, such as <a
441 href="#Constant"><tt>Constant</tt></a>s, <a
442 href="#Argument"><tt>Argument</tt></a>s, and even <a
443 href="#Instruction"><tt>Instruction</tt></a>s and <a
444 href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.<p>
446 A particular <tt>Value</tt> may be used many times in the LLVM representation
447 for a program. For example, an incoming argument to a function (represented
448 with an instance of the <a href="#Argument">Argument</a> class) is "used" by
449 every instruction in the function that references the argument. To keep track
450 of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
451 href="#User"><tt>User</tt></a>s that is using it (the <a
452 href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
453 graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
454 def-use information in the program, and is accessible through the <tt>use_</tt>*
455 methods, shown below.<p>
457 Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed, and
458 this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
459 method. <a name="#nameWarning">In addition, all LLVM values can be named. The
460 "name" of the <tt>Value</tt> is symbolic string printed in the LLVM code:<p>
463 %<b>foo</b> = add int 1, 2
466 The name of this instruction is "foo". <b>NOTE</b> that the name of any value
467 may be missing (an empty string), so names should <b>ONLY</b> be used for
468 debugging (making the source code easier to read, debugging printouts), they
469 should not be used to keep track of values or map between them. For this
470 purpose, use a <tt>std::map</tt> of pointers to the <tt>Value</tt> itself
473 One important aspect of LLVM is that there is no distinction between an SSA
474 variable and the operation that produces it. Because of this, any reference to
475 the value produced by an instruction (or the value available as an incoming
476 argument, for example) is represented as a direct pointer to the class that
477 represents this value. Although this may take some getting used to, it
478 simplifies the representation and makes it easier to manipulate.<p>
481 <!-- _______________________________________________________________________ -->
482 </ul><h4><a name="m_Value"><hr size=0>Important Public Members of
483 the <tt>Value</tt> class</h4><ul>
485 <li><tt>Value::use_iterator</tt> - Typedef for iterator over the use-list<br>
486 <tt>Value::use_const_iterator</tt>
487 - Typedef for const_iterator over the use-list<br>
488 <tt>unsigned use_size()</tt> - Returns the number of users of the value.<br>
489 <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
490 <tt>use_iterator use_begin()</tt>
491 - Get an iterator to the start of the use-list.<br>
492 <tt>use_iterator use_end()</tt>
493 - Get an iterator to the end of the use-list.<br>
494 <tt><a href="#User">User</a> *use_back()</tt>
495 - Returns the last element in the list.<p>
497 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>
499 <li><tt><a href="#Type">Type</a> *getType() const</tt><p>
500 This method returns the Type of the Value.
502 <li><tt>bool hasName() const</tt><br>
503 <tt>std::string getName() const</tt><br>
504 <tt>void setName(const std::string &Name)</tt><p>
506 This family of methods is used to access and assign a name to a <tt>Value</tt>,
507 be aware of the <a href="#nameWarning">precaution above</a>.<p>
510 <li><tt>void replaceAllUsesWith(Value *V)</tt><p>
512 This method traverses the use list of a <tt>Value</tt> changing all <a
513 href="#User"><tt>User</tt>'s</a> of the current value to refer to "<tt>V</tt>"
514 instead. For example, if you detect that an instruction always produces a
515 constant value (for example through constant folding), you can replace all uses
516 of the instruction with the constant like this:<p>
519 Inst->replaceAllUsesWith(ConstVal);
524 <!-- ======================================================================= -->
525 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
526 <tr><td> </td><td width="100%">
527 <font color="#EEEEFF" face="Georgia,Palatino"><b>
528 <a name="User">The <tt>User</tt> class</a>
529 </b></font></td></tr></table><ul>
531 <tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt></b><br>
532 doxygen info: <a href="/doxygen/classUser.html">User Class</a><br>
533 Superclass: <a href="#Value"><tt>Value</tt></a><p>
536 The <tt>User</tt> class is the common base class of all LLVM nodes that may
537 refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
538 that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
539 referring to. The <tt>User</tt> class itself is a subclass of
542 The operands of a <tt>User</tt> point directly to the LLVM <a
543 href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
544 Single Assignment (SSA) form, there can only be one definition referred to,
545 allowing this direct connection. This connection provides the use-def
546 information in LLVM.<p>
548 <!-- _______________________________________________________________________ -->
549 </ul><h4><a name="m_User"><hr size=0>Important Public Members of
550 the <tt>User</tt> class</h4><ul>
552 The <tt>User</tt> class exposes the operand list in two ways: through an index
553 access interface and through an iterator based interface.<p>
555 <li><tt>Value *getOperand(unsigned i)</tt><br>
556 <tt>unsigned getNumOperands()</tt><p>
558 These two methods expose the operands of the <tt>User</tt> in a convenient form
559 for direct access.<p>
561 <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand list<br>
562 <tt>User::op_const_iterator</tt>
563 <tt>use_iterator op_begin()</tt>
564 - Get an iterator to the start of the operand list.<br>
565 <tt>use_iterator op_end()</tt>
566 - Get an iterator to the end of the operand list.<p>
568 Together, these methods make up the iterator based interface to the operands of
573 <!-- ======================================================================= -->
574 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
575 <tr><td> </td><td width="100%">
576 <font color="#EEEEFF" face="Georgia,Palatino"><b>
577 <a name="Instruction">The <tt>Instruction</tt> class</a>
578 </b></font></td></tr></table><ul>
581 href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt></b><br>
582 doxygen info: <a href="/doxygen/classInstruction.html">Instruction Class</a><br>
583 Superclasses: <a href="#User"><tt>User</tt></a>, <a
584 href="#Value"><tt>Value</tt></a><p>
586 The <tt>Instruction</tt> class is the common base class for all LLVM
587 instructions. It provides only a few methods, but is a very commonly used
588 class. The primary data tracked by the <tt>Instruction</tt> class itself is the
589 opcode (instruction type) and the parent <a
590 href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
591 into. To represent a specific type of instruction, one of many subclasses of
592 <tt>Instruction</tt> are used.<p>
594 Because the <tt>Instruction</tt> class subclasses the <a
595 href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
596 way as for other <a href="#User"><tt>User</tt></a>s (with the
597 <tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
598 <tt>op_begin()</tt>/<tt>op_end()</tt> methods).<p>
601 <!-- _______________________________________________________________________ -->
602 </ul><h4><a name="m_Instruction"><hr size=0>Important Public Members of
603 the <tt>Instruction</tt> class</h4><ul>
605 <li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt><p>
607 Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that this
608 <tt>Instruction</tt> is embedded into.<p>
610 <li><tt>bool hasSideEffects()</tt><p>
612 Returns true if the instruction has side effects, i.e. it is a <tt>call</tt>,
613 <tt>free</tt>, <tt>invoke</tt>, or <tt>store</tt>.<p>
615 <li><tt>unsigned getOpcode()</tt><p>
617 Returns the opcode for the <tt>Instruction</tt>.<p>
621 \subsection{Subclasses of Instruction :}
623 <li>BinaryOperator : This subclass of Instruction defines a general interface to the all the instructions involvong binary operators in LLVM.
625 <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.
627 <li>TerminatorInst : This subclass of Instructions defines an interface for all instructions that can terminate a BasicBlock.
629 <li> <tt>unsigned getNumSuccessors()</tt>: Returns the number of successors for this terminator instruction.
630 <li><tt>BasicBlock *getSuccessor(unsigned i)</tt>: As the name suggests returns the ith successor BasicBlock.
631 <li><tt>void setSuccessor(unsigned i, BasicBlock *B)</tt>: sets BasicBlock B as the ith succesor to this terminator instruction.
634 <li>PHINode : This represents the PHI instructions in the SSA form.
636 <li><tt> unsigned getNumIncomingValues()</tt>: Returns the number of incoming edges to this PHI node.
637 <li><tt> Value *getIncomingValue(unsigned i)</tt>: Returns the ith incoming Value.
638 <li><tt>void setIncomingValue(unsigned i, Value *V)</tt>: Sets the ith incoming Value as V
639 <li><tt>BasicBlock *getIncomingBlock(unsigned i)</tt>: Returns the Basic Block corresponding to the ith incoming Value.
640 <li><tt> void addIncoming(Value *D, BasicBlock *BB)</tt>:
641 Add an incoming value to the end of the PHI list
642 <li><tt> int getBasicBlockIndex(const BasicBlock *BB) const</tt>:
643 Returns the first index of the specified basic block in the value list for this PHI. Returns -1 if no instance.
645 <li>CastInst : In LLVM all casts have to be done through explicit cast instructions. CastInst defines the interface to the cast instructions.
646 <li>CallInst : This defines an interface to the call instruction in LLVM. ARguments to the function are nothing but operands of the instruction.
648 <li>: <tt>Function *getCalledFunction()</tt>: Returns a handle to the function that is being called by this Function.
650 <li>LoadInst, StoreInst, GetElemPtrInst : These subclasses represent load, store and getelementptr instructions in LLVM.
652 <li><tt>Value * getPointerOperand ()</tt>: Returns the Pointer Operand which is typically the 0th operand.
654 <li>BranchInst : This is a subclass of TerminatorInst and defines the interface for conditional and unconditional branches in LLVM.
656 <li><tt>bool isConditional()</tt>: Returns true if the branch is a conditional branch else returns false
657 <li> <tt>Value *getCondition()</tt>: Returns the condition if it is a conditional branch else returns null.
658 <li> <tt>void setUnconditionalDest(BasicBlock *Dest)</tt>: Changes the current branch to an unconditional one targetting the specified block.
666 <!-- ======================================================================= -->
667 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
668 <tr><td> </td><td width="100%">
669 <font color="#EEEEFF" face="Georgia,Palatino"><b>
670 <a name="BasicBlock">The <tt>BasicBlock</tt> class</a>
671 </b></font></td></tr></table><ul>
674 href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt></b><br>
675 doxygen info: <a href="/doxygen/classBasicBlock.html">BasicBlock Class</a><br>
676 Superclass: <a href="#Value"><tt>Value</tt></a><p>
679 This class represents a single entry multiple exit section of the code, commonly
680 known as a basic block by the compiler community. The <tt>BasicBlock</tt> class
681 maintains a list of <a href="#Instruction"><tt>Instruction</tt></a>s, which form
682 the body of the block. Matching the language definition, the last element of
683 this list of instructions is always a terminator instruction (a subclass of the
684 <a href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).<p>
686 In addition to tracking the list of instructions that make up the block, the
687 <tt>BasicBlock</tt> class also keeps track of the <a
688 href="#Function"><tt>Function</tt></a> that it is embedded into.<p>
690 Note that <tt>BasicBlock</tt>s themselves are <a
691 href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
692 like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
696 <!-- _______________________________________________________________________ -->
697 </ul><h4><a name="m_BasicBlock"><hr size=0>Important Public Members of
698 the <tt>BasicBlock</tt> class</h4><ul>
700 <li><tt>BasicBlock(const std::string &Name = "", <a
701 href="#Function">Function</a> *Parent = 0)</tt><p>
703 The <tt>BasicBlock</tt> constructor is used to create new basic blocks for
704 insertion into a function. The constructor simply takes a name for the new
705 block, and optionally a <a href="#Function"><tt>Function</tt></a> to insert it
706 into. If the <tt>Parent</tt> parameter is specified, the new
707 <tt>BasicBlock</tt> is automatically inserted at the end of the specified <a
708 href="#Function"><tt>Function</tt></a>, if not specified, the BasicBlock must be
709 manually inserted into the <a href="#Function"><tt>Function</tt></a>.<p>
711 <li><tt>BasicBlock::iterator</tt> - Typedef for instruction list iterator<br>
712 <tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
713 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
714 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
716 These methods and typedefs are forwarding functions that have the same semantics
717 as the standard library methods of the same names. These methods expose the
718 underlying instruction list of a basic block in a way that is easy to
719 manipulate. To get the full complement of container operations (including
720 operations to update the list), you must use the <tt>getInstList()</tt>
723 <li><tt>BasicBlock::InstListType &getInstList()</tt><p>
725 This method is used to get access to the underlying container that actually
726 holds the Instructions. This method must be used when there isn't a forwarding
727 function in the <tt>BasicBlock</tt> class for the operation that you would like
728 to perform. Because there are no forwarding functions for "updating"
729 operations, you need to use this if you want to update the contents of a
730 <tt>BasicBlock</tt>.<p>
732 <li><tt><A href="#Function">Function</a> *getParent()</tt><p>
734 Returns a pointer to <a href="#Function"><tt>Function</tt></a> the block is
735 embedded into, or a null pointer if it is homeless.<p>
737 <li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt><p>
739 Returns a pointer to the terminator instruction that appears at the end of the
740 <tt>BasicBlock</tt>. If there is no terminator instruction, or if the last
741 instruction in the block is not a terminator, then a null pointer is
745 <!-- ======================================================================= -->
746 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
747 <tr><td> </td><td width="100%">
748 <font color="#EEEEFF" face="Georgia,Palatino"><b>
749 <a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
750 </b></font></td></tr></table><ul>
753 href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt></b><br>
754 doxygen info: <a href="/doxygen/classGlobalValue.html">GlobalValue Class</a><br>
755 Superclasses: <a href="#User"><tt>User</tt></a>, <a
756 href="#Value"><tt>Value</tt></a><p>
758 Global values (<A href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
759 href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
760 visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
761 Because they are visible at global scope, they are also subject to linking with
762 other globals defined in different translation units. To control the linking
763 process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
764 <tt>GlobalValue</tt>s know whether they have internal or external linkage.<p>
766 If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
767 <tt>static</tt> in C), it is not visible to code outside the current translation
768 unit, and does not participate in linking. If it has external linkage, it is
769 visible to external code, and does participate in linking. In addition to
770 linkage information, <tt>GlobalValue</tt>s keep track of which <a
771 href="#Module"><tt>Module</tt></a> they are currently part of.<p>
773 Because <tt>GlobalValue</tt>s are memory objects, they are always referred to by
774 their address. As such, the <a href="#Type"><tt>Type</tt></a> of a global is
775 always a pointer to its contents. This is explained in the LLVM Language
779 <!-- _______________________________________________________________________ -->
780 </ul><h4><a name="m_GlobalValue"><hr size=0>Important Public Members of
781 the <tt>GlobalValue</tt> class</h4><ul>
783 <li><tt>bool hasInternalLinkage() const</tt><br>
784 <tt>bool hasExternalLinkage() const</tt><br>
785 <tt>void setInternalLinkage(bool HasInternalLinkage)</tt><p>
787 These methods manipulate the linkage characteristics of the
788 <tt>GlobalValue</tt>.<p>
790 <li><tt><a href="#Module">Module</a> *getParent()</tt><p>
792 This returns the <a href="#Module"><tt>Module</tt></a> that the GlobalValue is
793 currently embedded into.<p>
797 <!-- ======================================================================= -->
798 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
799 <tr><td> </td><td width="100%">
800 <font color="#EEEEFF" face="Georgia,Palatino"><b>
801 <a name="Function">The <tt>Function</tt> class</a>
802 </b></font></td></tr></table><ul>
805 href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt></b><br>
806 doxygen info: <a href="/doxygen/classFunction.html">Function Class</a><br>
807 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
808 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
810 The <tt>Function</tt> class represents a single procedure in LLVM. It is
811 actually one of the more complex classes in the LLVM heirarchy because it must
812 keep track of a large amount of data. The <tt>Function</tt> class keeps track
813 of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
814 href="#Argument"><tt>Argument</tt></a>s, and a <a
815 href="#SymbolTable"><tt>SymbolTable</tt></a>.<p>
817 The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most commonly
818 used part of <tt>Function</tt> objects. The list imposes an implicit ordering
819 of the blocks in the function, which indicate how the code will be layed out by
820 the backend. Additionally, the first <a
821 href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
822 <tt>Function</tt>. It is not legal in LLVM explicitly branch to this initial
823 block. There are no implicit exit nodes, and in fact there may be multiple exit
824 nodes from a single <tt>Function</tt>. If the <a
825 href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
826 the <tt>Function</tt> is actually a function declaration: the actual body of the
827 function hasn't been linked in yet.<p>
829 In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
830 <tt>Function</tt> class also keeps track of the list of formal <a
831 href="#Argument"><tt>Argument</tt></a>s that the function receives. This
832 container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
833 nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
834 the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.<p>
836 The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used LLVM
837 feature that is only used when you have to look up a value by name. Aside from
838 that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used internally to
839 make sure that there are not conflicts between the names of <a
840 href="#Instruction"><tt>Instruction</tt></a>s, <a
841 href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
842 href="#Argument"><tt>Argument</tt></a>s in the function body.<p>
845 <!-- _______________________________________________________________________ -->
846 </ul><h4><a name="m_Function"><hr size=0>Important Public Members of
847 the <tt>Function</tt> class</h4><ul>
849 <li><tt>Function(const <a href="#FunctionType">FunctionType</a> *Ty, bool isInternal, const std::string &N = "")</tt><p>
851 Constructor used when you need to create new <tt>Function</tt>s to add the the
852 program. The constructor must specify the type of the function to create and
853 whether or not it should start out with internal or external linkage.<p>
855 <li><tt>bool isExternal()</tt><p>
857 Return whether or not the <tt>Function</tt> has a body defined. If the function
858 is "external", it does not have a body, and thus must be resolved by linking
859 with a function defined in a different translation unit.<p>
862 <li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
863 <tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
864 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
865 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
867 These are forwarding methods that make it easy to access the contents of a
868 <tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
871 <li><tt>Function::BasicBlockListType &getBasicBlockList()</tt><p>
873 Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This is
874 neccesary to use when you need to update the list or perform a complex action
875 that doesn't have a forwarding method.<p>
878 <li><tt>Function::aiterator</tt> - Typedef for the argument list iterator<br>
879 <tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
880 <tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
881 <tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt><p>
883 These are forwarding methods that make it easy to access the contents of a
884 <tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a> list.<p>
886 <li><tt>Function::ArgumentListType &getArgumentList()</tt><p>
888 Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This is
889 neccesary to use when you need to update the list or perform a complex action
890 that doesn't have a forwarding method.<p>
894 <li><tt><a href="#BasicBlock">BasicBlock</a> &getEntryNode()</tt><p>
896 Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
897 function. Because the entry block for the function is always the first block,
898 this returns the first block of the <tt>Function</tt>.<p>
900 <li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
901 <tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt><p>
903 This traverses the <a href="#Type"><tt>Type</tt></a> of the <tt>Function</tt>
904 and returns the return type of the function, or the <a
905 href="#FunctionType"><tt>FunctionType</tt></a> of the actual function.<p>
908 <li><tt>bool hasSymbolTable() const</tt><p>
910 Return true if the <tt>Function</tt> has a symbol table allocated to it and if
911 there is at least one entry in it.<p>
913 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
915 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
916 <tt>Function</tt> or a null pointer if one has not been allocated (because there
917 are no named values in the function).<p>
919 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
921 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
922 <tt>Function</tt> or allocate a new <a
923 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
924 should only be used when adding elements to the <a
925 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
926 not left laying around.<p>
930 <!-- ======================================================================= -->
931 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
932 <tr><td> </td><td width="100%">
933 <font color="#EEEEFF" face="Georgia,Palatino"><b>
934 <a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
935 </b></font></td></tr></table><ul>
938 href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt></b><br>
939 doxygen info: <a href="/doxygen/classGlobalVariable.html">GlobalVariable Class</a><br>
940 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
941 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
943 Global variables are represented with the (suprise suprise)
944 <tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are
945 also subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such
946 are always referenced by their address (global values must live in memory, so
947 their "name" refers to their address). Global variables may have an initial
948 value (which must be a <a href="#Constant"><tt>Constant</tt></a>), and if they
949 have an initializer, they may be marked as "constant" themselves (indicating
950 that their contents never change at runtime).<p>
953 <!-- _______________________________________________________________________ -->
954 </ul><h4><a name="m_GlobalVariable"><hr size=0>Important Public Members of the
955 <tt>GlobalVariable</tt> class</h4><ul>
957 <li><tt>GlobalVariable(const <a href="#Type">Type</a> *Ty, bool isConstant, bool
958 isInternal, <a href="#Constant">Constant</a> *Initializer = 0, const std::string
959 &Name = "")</tt><p>
961 Create a new global variable of the specified type. If <tt>isConstant</tt> is
962 true then the global variable will be marked as unchanging for the program, and
963 if <tt>isInternal</tt> is true the resultant global variable will have internal
964 linkage. Optionally an initializer and name may be specified for the global variable as well.<p>
967 <li><tt>bool isConstant() const</tt><p>
969 Returns true if this is a global variable is known not to be modified at
973 <li><tt>bool hasInitializer()</tt><p>
975 Returns true if this <tt>GlobalVariable</tt> has an intializer.<p>
978 <li><tt><a href="#Constant">Constant</a> *getInitializer()</tt><p>
980 Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal to call
981 this method if there is no initializer.<p>
984 <!-- ======================================================================= -->
985 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
986 <tr><td> </td><td width="100%">
987 <font color="#EEEEFF" face="Georgia,Palatino"><b>
988 <a name="Module">The <tt>Module</tt> class</a>
989 </b></font></td></tr></table><ul>
992 href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt></b><br>
993 doxygen info: <a href="/doxygen/classModule.html">Module Class</a><p>
995 The <tt>Module</tt> class represents the top level structure present in LLVM
996 programs. An LLVM module is effectively either a translation unit of the
997 original program or a combination of several translation units merged by the
998 linker. The <tt>Module</tt> class keeps track of a list of <a
999 href="#Function"><tt>Function</tt></a>s, a list of <a
1000 href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
1001 href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
1002 helpful member functions that try to make common operations easy.<p>
1005 <!-- _______________________________________________________________________ -->
1006 </ul><h4><a name="m_Module"><hr size=0>Important Public Members of the
1007 <tt>Module</tt> class</h4><ul>
1009 <li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
1010 <tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
1011 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
1012 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
1014 These are forwarding methods that make it easy to access the contents of a
1015 <tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
1018 <li><tt>Module::FunctionListType &getFunctionList()</tt><p>
1020 Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
1021 neccesary to use when you need to update the list or perform a complex action
1022 that doesn't have a forwarding method.<p>
1024 <!-- Global Variable -->
1027 <li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
1028 <tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
1029 <tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
1030 <tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt><p>
1032 These are forwarding methods that make it easy to access the contents of a
1033 <tt>Module</tt> object's <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>
1036 <li><tt>Module::GlobalListType &getGlobalList()</tt><p>
1038 Returns the list of <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s.
1039 This is neccesary to use when you need to update the list or perform a complex
1040 action that doesn't have a forwarding method.<p>
1043 <!-- Symbol table stuff -->
1046 <li><tt>bool hasSymbolTable() const</tt><p>
1048 Return true if the <tt>Module</tt> has a symbol table allocated to it and if
1049 there is at least one entry in it.<p>
1051 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
1053 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1054 <tt>Module</tt> or a null pointer if one has not been allocated (because there
1055 are no named values in the function).<p>
1057 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
1059 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1060 <tt>Module</tt> or allocate a new <a
1061 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
1062 should only be used when adding elements to the <a
1063 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
1064 not left laying around.<p>
1067 <!-- Convenience methods -->
1070 <li><tt><a href="#Function">Function</a> *getFunction(const std::string &Name, const <a href="#FunctionType">FunctionType</a> *Ty)</tt><p>
1072 Look up the specified function in the <tt>Module</tt> <a
1073 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
1077 <li><tt><a href="#Function">Function</a> *getOrInsertFunction(const std::string
1078 &Name, const <a href="#FunctionType">FunctionType</a> *T)</tt><p>
1080 Look up the specified function in the <tt>Module</tt> <a
1081 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, add an
1082 external declaration for the function and return it.<p>
1085 <li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt><p>
1087 If there is at least one entry in the <a
1088 href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
1089 href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
1093 <li><tt>bool addTypeName(const std::string &Name, const <a href="#Type">Type</a>
1096 Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a> mapping
1097 <tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this name, true
1098 is returned and the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is not
1102 <!-- ======================================================================= -->
1103 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1104 <tr><td> </td><td width="100%">
1105 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1106 <a name="Constant">The <tt>Constant</tt> class and subclasses</a>
1107 </b></font></td></tr></table><ul>
1109 Constant represents a base class for different types of constants. It is
1110 subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
1111 ConstantArray etc for representing the various types of Constants.<p>
1114 <!-- _______________________________________________________________________ -->
1115 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1117 <li><tt>bool isConstantExpr()</tt>: Returns true if it is a ConstantExpr
1122 \subsection{Important Subclasses of Constant}
1124 <li>ConstantSInt : This subclass of Constant represents a signed integer constant.
1126 <li><tt>int64_t getValue () const</tt>: Returns the underlying value of this constant.
1128 <li>ConstantUInt : This class represents an unsigned integer.
1130 <li><tt>uint64_t getValue () const</tt>: Returns the underlying value of this constant.
1132 <li>ConstantFP : This class represents a floating point constant.
1134 <li><tt>double getValue () const</tt>: Returns the underlying value of this constant.
1136 <li>ConstantBool : This represents a boolean constant.
1138 <li><tt>bool getValue () const</tt>: Returns the underlying value of this constant.
1140 <li>ConstantArray : This represents a constant array.
1142 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1144 <li>ConstantStruct : This represents a constant struct.
1146 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1148 <li>ConstantPointerRef : This represents a constant pointer value that is initialized to point to a global value, which lies at a constant fixed address.
1150 <li><tt>GlobalValue *getValue()</tt>: Returns the global value to which this pointer is pointing to.
1155 <!-- ======================================================================= -->
1156 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1157 <tr><td> </td><td width="100%">
1158 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1159 <a name="Type">The <tt>Type</tt> class and Derived Types</a>
1160 </b></font></td></tr></table><ul>
1162 Type as noted earlier is also a subclass of a Value class. Any primitive
1163 type (like int, short etc) in LLVM is an instance of Type Class. All
1164 other types are instances of subclasses of type like FunctionType,
1165 ArrayType etc. DerivedType is the interface for all such dervied types
1166 including FunctionType, ArrayType, PointerType, StructType. Types can have
1167 names. They can be recursive (StructType). There exists exactly one instance
1168 of any type structure at a time. This allows using pointer equality of Type *s for comparing types.
1170 <!-- _______________________________________________________________________ -->
1171 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1173 <li><tt>PrimitiveID getPrimitiveID () const</tt>: Returns the base type of the type.
1174 <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.
1175 <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.
1176 <li><tt> bool isInteger () const</tt>: Equilivent to isSigned() || isUnsigned(), but with only a single virtual function invocation.
1177 <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.
1179 <li><tt>bool isFloatingPoint ()</tt>: Return true if this is one of the two floating point types.
1180 <li><tt>bool isRecursive () const</tt>: Returns rue if the type graph contains a cycle.
1181 <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.
1182 <li><tt>bool isPrimitiveType () const</tt>: Returns true if it is a primitive type.
1183 <li><tt>bool isDerivedType () const</tt>: Returns true if it is a derived type.
1184 <li><tt>const Type * getContainedType (unsigned i) const</tt>:
1185 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.
1186 <li><tt>unsigned getNumContainedTypes () const</tt>: Return the number of types in the derived type.
1190 \subsection{Derived Types}
1192 <li>SequentialType : This is subclassed by ArrayType and PointerType
1194 <li><tt>const Type * getElementType () const</tt>: Returns the type of each of the elements in the sequential type.
1196 <li>ArrayType : This is a subclass of SequentialType and defines interface for array types.
1198 <li><tt>unsigned getNumElements () const</tt>: Returns the number of elements in the array.
1200 <li>PointerType : Subclass of SequentialType for pointer types.
1201 <li>StructType : subclass of DerivedTypes for struct types
1202 <li>FunctionType : subclass of DerivedTypes for function types.
1205 <li><tt>bool isVarArg () const</tt>: Returns true if its a vararg function
1206 <li><tt> const Type * getReturnType () const</tt>: Returns the return type of the function.
1207 <li><tt> const ParamTypes &getParamTypes () const</tt>: Returns a vector of parameter types.
1208 <li><tt>const Type * getParamType (unsigned i)</tt>: Returns the type of the ith parameter.
1209 <li><tt> const unsigned getNumParams () const</tt>: Returns the number of formal parameters.
1216 <!-- ======================================================================= -->
1217 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1218 <tr><td> </td><td width="100%">
1219 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1220 <a name="Argument">The <tt>Argument</tt> class</a>
1221 </b></font></td></tr></table><ul>
1223 This subclass of Value defines the interface for incoming formal arguments to a
1224 function. A Function maitanis a list of its formal arguments. An argument has a
1225 pointer to the parent Function.
1230 <!-- *********************************************************************** -->
1232 <!-- *********************************************************************** -->
1235 <address>By: <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
1236 <a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
1237 <!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
1238 <!-- hhmts start -->
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