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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>
74 <li><a href="#GlobalValue">The <tt>GlobalValue</tt> class</a>
76 <li><a href="#BasicBlock">The <tt>BasicBlock</tt> class</a>
77 <li><a href="#Function">The <tt>Function</tt> class</a>
78 <li><a href="#GlobalVariable">The <tt>GlobalVariable</tt> class</a>
80 <li><a href="#Module">The <tt>Module</tt> class</a>
81 <li><a href="#Constant">The <tt>Constant</tt> class</a>
87 <li><a href="#Type">The <tt>Type</tt> class</a>
88 <li><a href="#Argument">The <tt>Argument</tt> class</a>
90 <li>The <tt>SymbolTable</tt> class
91 <li>The <tt>ilist</tt> and <tt>iplist</tt> classes
93 <li>Creating, inserting, moving and deleting from LLVM lists
95 <li>Important iterator invalidation semantics to be aware of
98 <p><b>Written by <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a>
99 <a href="mailto:sabre@nondot.org">Chris Lattner</a>, and
100 <a href="mailto:jstanley@cs.uiuc.edu">Joel Stanley</a></b><p>
104 <!-- *********************************************************************** -->
105 <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
106 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
107 <a name="introduction">Introduction
108 </b></font></td></tr></table><ul>
109 <!-- *********************************************************************** -->
111 This document is meant to highlight some of the important classes and interfaces
112 available in the LLVM source-base. This manual is not intended to explain what
113 LLVM is, how it works, and what LLVM code looks like. It assumes that you know
114 the basics of LLVM and are interested in writing transformations or otherwise
115 analyzing or manipulating the code.<p>
117 This document should get you oriented so that you can find your way in the
118 continuously growing source code that makes up the LLVM infrastructure. Note
119 that this manual is not intended to serve as a replacement for reading the
120 source code, so if you think there should be a method in one of these classes to
121 do something, but it's not listed, check the source. Links to the <a
122 href="/doxygen/">doxygen</a> sources are provided to make this as easy as
125 The first section of this document describes general information that is useful
126 to know when working in the LLVM infrastructure, and the second describes the
127 Core LLVM classes. In the future this manual will be extended with information
128 describing how to use extension libraries, such as dominator information, CFG
129 traversal routines, and useful utilities like the <tt><a
130 href="/doxygen/InstVisitor_8h-source.html">InstVisitor</a></tt> template.<p>
133 <!-- *********************************************************************** -->
134 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
135 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
136 <a name="general">General Information
137 </b></font></td></tr></table><ul>
138 <!-- *********************************************************************** -->
140 This section contains general information that is useful if you are working in
141 the LLVM source-base, but that isn't specific to any particular API.<p>
144 <!-- ======================================================================= -->
145 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
146 <tr><td> </td><td width="100%">
147 <font color="#EEEEFF" face="Georgia,Palatino"><b>
148 <a name="stl">The C++ Standard Template Library</a>
149 </b></font></td></tr></table><ul>
151 LLVM makes heavy use of the C++ Standard Template Library (STL), perhaps much
152 more than you are used to, or have seen before. Because of this, you might want
153 to do a little background reading in the techniques used and capabilities of the
154 library. There are many good pages that discuss the STL, and several books on
155 the subject that you can get, so it will not be discussed in this document.<p>
157 Here are some useful links:<p>
159 <li><a href="http://www.dinkumware.com/htm_cpl/index.html">Dinkumware C++
160 Library reference</a> - an excellent reference for the STL and other parts of
161 the standard C++ library.<br>
163 <li><a href="http://www.parashift.com/c++-faq-lite/">C++ Frequently Asked
166 <li><a href="http://www.sgi.com/tech/stl/">SGI's STL Programmer's Guide</a> -
168 href="http://www.sgi.com/tech/stl/stl_introduction.html">Introduction to the
171 <li><a href="http://www.research.att.com/~bs/C++.html">Bjarne Stroustrup's C++
176 You are also encouraged to take a look at the <a
177 href="CodingStandards.html">LLVM Coding Standards</a> guide which focuses on how
178 to write maintainable code more than where to put your curly braces.<p>
182 <!-- *********************************************************************** -->
183 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
184 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
185 <a name="common">Helpful Hints for Common Operations
186 </b></font></td></tr></table><ul>
187 <!-- *********************************************************************** -->
189 This section describes how to perform some very simple transformations of LLVM
190 code. This is meant to give examples of common idioms used, showing the
191 practical side of LLVM transformations.<p>
193 Because this is a "how-to" section, you should also read about the main classes
194 that you will be working with. The <a href="#coreclasses">Core LLVM Class
195 Hierarchy Reference</a> contains details and descriptions of the main classes
196 that you should know about.<p>
198 <!-- NOTE: this section should be heavy on example code -->
201 <!-- ======================================================================= -->
202 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
203 <tr><td> </td><td width="100%">
204 <font color="#EEEEFF" face="Georgia,Palatino"><b>
205 <a name="inspection">Basic Inspection and Traversal Routines</a>
206 </b></font></td></tr></table><ul>
209 <!-- LLVM has heirarchical representation: Module, Function, BasicBlock,
210 Instruction. Common patterns for all levels. -->
212 <!-- _______________________________________________________________________ -->
213 </ul><h4><a name="iterate_function"><hr size=0>Iterating over the
214 <tt>BasicBlock</tt>s in a <tt>Function</tt> </h4><ul>
216 It's quite common to have a <tt>Function</tt> instance that you'd like
217 to transform in some way; in particular, you'd like to manipulate its
218 <tt>BasicBlock</tt>s. To facilitate this, you'll need to iterate over
219 all of the <tt>BasicBlock</tt>s that constitute the <tt>Function</tt>.
220 The following is an example that prints the name of a
221 <tt>BasicBlock</tt> and the number of <tt>Instruction</tt>s it
225 // func is a pointer to a Function instance
226 for(Function::iterator i = func->begin(), e = func->end(); i != e; ++i) {
228 // print out the name of the basic block if it has one, and then the
229 // number of instructions that it contains
231 cerr << "Basic block (name=" << i->getName() << ") has "
232 << i->size() << " instructions.\n";
236 Note that i can be used as if it were a pointer for the purposes of
237 invoking member functions of the <tt>Instruction</tt> class. This is
238 because the indirection operator is overloaded for the iterator
239 classes. In the above code, the expression <tt>i->size()</tt> is
240 exactly equivalent to <tt>(*i).size()</tt> just like you'd expect.
242 <!-- _______________________________________________________________________ -->
243 </ul><h4><a name="iterate_basicblock"><hr size=0>Iterating over the
244 <tt>Instruction</tt>s in a <tt>BasicBlock</tt> </h4><ul>
246 Just like when dealing with <tt>BasicBlock</tt>s in
247 <tt>Function</tt>s, it's easy to iterate over the individual
248 instructions that make up <tt>BasicBlock</tt>s. Here's a code snippet
249 that prints out each instruction in a <tt>BasicBlock</tt>:
252 // blk is a pointer to a BasicBlock instance
253 for(BasicBlock::iterator i = blk->begin(), e = blk->end(); i != e; ++i) {
254 // the next statement works since operator<<(ostream&,...)
255 // is overloaded for Instruction&
256 cerr << *i << endl;
259 However, this isn't really the best way to print out the contents of a
260 <tt>BasicBlock</tt>! Since the ostream operators are overloaded for
261 virtually anything you'll care about, you could have just invoked the
262 print routine on the basic block itself: <tt>cerr << *blk <<
265 Note that currently operator<< is implemented for <tt>Value*</tt>, so it
266 will print out the contents of the pointer, instead of
267 the pointer value you might expect. This is a deprecated interface that will
268 be removed in the future, so it's best not to depend on it. To print out the
269 pointer value for now, you must cast to <tt>void*</tt>.<p>
271 <!-- _______________________________________________________________________ -->
272 </ul><h4><a name="iterate_convert"><hr size=0>Turning an iterator into a class
275 Sometimes, it'll be useful to grab a reference (or pointer) to a class
276 instance when all you've got at hand is an iterator. Well, extracting
277 a reference or a pointer from an iterator is very straightforward.
278 Assuming that <tt>i</tt> is a <tt>BasicBlock::iterator</tt> and
279 <tt>j</tt> is a <tt>BasicBlock::const_iterator</tt>:
282 Instruction& inst = *i; // grab reference to instruction reference
283 Instruction* pinst = &*i; // grab pointer to instruction reference
284 const Instruction& inst = *j;
286 However, the iterators you'll be working with in the LLVM framework
287 are special: they will automatically convert to a ptr-to-instance type
288 whenever they need to. Instead of dereferencing the iterator and then
289 taking the address of the result, you can simply assign the iterator
290 to the proper pointer type and you get the dereference and address-of
291 operation as a result of the assignment (behind the scenes, this is a
292 result of overloading casting mechanisms). Thus the last line of the
295 <pre>Instruction* pinst = &*i;</pre>
297 is semantically equivalent to
299 <pre>Instruction* pinst = i;</pre>
301 <b>Caveat emptor</b>: The above syntax works <i>only</i> when you're
302 <i>not</i> working with <tt>dyn_cast</tt>. The template definition of
303 <tt>dyn_cast</tt> isn't implemented to handle this yet, so you'll
304 still need the following in order for things to work properly:
307 BasicBlock::iterator bbi = ...;
308 BranchInst* b = dyn_cast<BranchInst>(&*bbi);
311 The following code snippet illustrates use of the conversion
312 constructors provided by LLVM iterators. By using these, you can
313 explicitly grab the iterator of something without actually obtaining
314 it via iteration over some structure:
317 void printNextInstruction(Instruction* inst) {
318 BasicBlock::iterator it(inst);
319 ++it; // after this line, it refers to the instruction after *inst.
320 if(it != inst->getParent()->end()) cerr << *it << endl;
323 Of course, this example is strictly pedagogical, because it'd be much
324 better to explicitly grab the next instruction directly from inst.
326 <!-- dereferenced iterator = Class &
327 iterators have converting constructor for 'Class *'
328 iterators automatically convert to 'Class *' except in dyn_cast<> case
332 _______________________________________________________________________
333 --> </ul><h4><a name="iterate_complex"><hr size=0>Finding call sites:
334 a slightly more complex example
337 Say that you're writing a FunctionPass and would like to count all the
338 locations in the entire module (that is, across every <tt>Function</tt>)
339 where a certain function named foo (that takes an int and returns an
340 int) is called. As you'll learn later, you may want to use an
341 <tt>InstVisitor</tt> to accomplish this in a much more straightforward
342 manner, but this example will allow us to explore how you'd do it if
343 you didn't have <tt>InstVisitor</tt> around. In pseudocode, this is
347 initialize callCounter to zero
348 for each Function f in the Module
349 for each BasicBlock b in f
350 for each Instruction i in b
351 if(i is a CallInst and foo is the function it calls)
352 increment callCounter
355 And the actual code is (remember, since we're writing a
356 <tt>FunctionPass</tt> our <tt>FunctionPass</tt>-derived class simply
357 has to override the <tt>runOnFunction</tt> method...):
361 // Assume callCounter is a private member of the pass class being written,
362 // and has been initialized in the pass class constructor.
364 virtual runOnFunction(Function& F) {
366 // Remember, we assumed that the signature of foo was "int foo(int)";
367 // the first thing we'll do is grab the pointer to that function (as a
368 // Function*) so we can use it later when we're examining the
369 // parameters of a CallInst. All of the code before the call to
370 // Module::getOrInsertFunction() is in preparation to do symbol-table
371 // to find the function pointer.
373 vector<const Type*> params;
374 params.push_back(Type::IntTy);
375 const FunctionType* fooType = FunctionType::get(Type::IntTy, params);
376 Function* foo = F.getParent()->getOrInsertFunction("foo", fooType);
378 // Start iterating and (as per the pseudocode), increment callCounter.
380 for(Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
381 for(BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {
382 if(CallInst* callInst = dyn_cast<CallInst>(&*inst)) {
383 // we know we've encountered a call instruction, so we
384 // need to determine if it's a call to foo or not
386 if(callInst->getCalledFunction() == foo)
394 We could then print out the value of callCounter (if we wanted to)
395 inside the doFinalization method of our FunctionPass.
397 <!-- ======================================================================= -->
398 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
399 <tr><td> </td><td width="100%">
400 <font color="#EEEEFF" face="Georgia,Palatino"><b>
401 <a name="simplechanges">Making simple changes</a>
402 </b></font></td></tr></table><ul>
404 <!-- Value::replaceAllUsesWith
405 User::replaceUsesOfWith
406 Point out: include/llvm/Transforms/Utils/
407 especially BasicBlockUtils.h with:
408 ReplaceInstWithValue, ReplaceInstWithInst
413 <!-- *********************************************************************** -->
414 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
415 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
416 <a name="coreclasses">The Core LLVM Class Hierarchy Reference
417 </b></font></td></tr></table><ul>
418 <!-- *********************************************************************** -->
420 The Core LLVM classes are the primary means of representing the program being
421 inspected or transformed. The core LLVM classes are defined in header files in
422 the <tt>include/llvm/</tt> directory, and implemented in the <tt>lib/VMCore</tt>
426 <!-- ======================================================================= -->
427 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
428 <tr><td> </td><td width="100%">
429 <font color="#EEEEFF" face="Georgia,Palatino"><b>
430 <a name="Value">The <tt>Value</tt> class</a>
431 </b></font></td></tr></table><ul>
433 <tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt></b><br>
434 doxygen info: <a href="/doxygen/classValue.html">Value Class</a><p>
437 The <tt>Value</tt> class is the most important class in LLVM Source base. It
438 represents a typed value that may be used (among other things) as an operand to
439 an instruction. There are many different types of <tt>Value</tt>s, such as <a
440 href="#Constant"><tt>Constant</tt></a>s, <a
441 href="#Argument"><tt>Argument</tt></a>s, and even <a
442 href="#Instruction"><tt>Instruction</tt></a>s and <a
443 href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.<p>
445 A particular <tt>Value</tt> may be used many times in the LLVM representation
446 for a program. For example, an incoming argument to a function (represented
447 with an instance of the <a href="#Argument">Argument</a> class) is "used" by
448 every instruction in the function that references the argument. To keep track
449 of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
450 href="#User"><tt>User</tt></a>s that is using it (the <a
451 href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
452 graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
453 def-use information in the program, and is accessible through the <tt>use_</tt>*
454 methods, shown below.<p>
456 Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed, and
457 this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
458 method. <a name="#nameWarning">In addition, all LLVM values can be named. The
459 "name" of the <tt>Value</tt> is symbolic string printed in the LLVM code:<p>
462 %<b>foo</b> = add int 1, 2
465 The name of this instruction is "foo". <b>NOTE</b> that the name of any value
466 may be missing (an empty string), so names should <b>ONLY</b> be used for
467 debugging (making the source code easier to read, debugging printouts), they
468 should not be used to keep track of values or map between them. For this
469 purpose, use a <tt>std::map</tt> of pointers to the <tt>Value</tt> itself
472 One important aspect of LLVM is that there is no distinction between an SSA
473 variable and the operation that produces it. Because of this, any reference to
474 the value produced by an instruction (or the value available as an incoming
475 argument, for example) is represented as a direct pointer to the class that
476 represents this value. Although this may take some getting used to, it
477 simplifies the representation and makes it easier to manipulate.<p>
480 <!-- _______________________________________________________________________ -->
481 </ul><h4><a name="m_Value"><hr size=0>Important Public Members of
482 the <tt>Value</tt> class</h4><ul>
484 <li><tt>Value::use_iterator</tt> - Typedef for iterator over the use-list<br>
485 <tt>Value::use_const_iterator</tt>
486 - Typedef for const_iterator over the use-list<br>
487 <tt>unsigned use_size()</tt> - Returns the number of users of the value.<br>
488 <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
489 <tt>use_iterator use_begin()</tt>
490 - Get an iterator to the start of the use-list.<br>
491 <tt>use_iterator use_end()</tt>
492 - Get an iterator to the end of the use-list.<br>
493 <tt><a href="#User">User</a> *use_back()</tt>
494 - Returns the last element in the list.<p>
496 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>
498 <li><tt><a href="#Type">Type</a> *getType() const</tt><p>
499 This method returns the Type of the Value.
501 <li><tt>bool hasName() const</tt><br>
502 <tt>std::string getName() const</tt><br>
503 <tt>void setName(const std::string &Name)</tt><p>
505 This family of methods is used to access and assign a name to a <tt>Value</tt>,
506 be aware of the <a href="#nameWarning">precaution above</a>.<p>
509 <li><tt>void replaceAllUsesWith(Value *V)</tt><p>
511 This method traverses the use list of a <tt>Value</tt> changing all <a
512 href="#User"><tt>User</tt>'s</a> of the current value to refer to "<tt>V</tt>"
513 instead. For example, if you detect that an instruction always produces a
514 constant value (for example through constant folding), you can replace all uses
515 of the instruction with the constant like this:<p>
518 Inst->replaceAllUsesWith(ConstVal);
523 <!-- ======================================================================= -->
524 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
525 <tr><td> </td><td width="100%">
526 <font color="#EEEEFF" face="Georgia,Palatino"><b>
527 <a name="User">The <tt>User</tt> class</a>
528 </b></font></td></tr></table><ul>
530 <tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt></b><br>
531 doxygen info: <a href="/doxygen/classUser.html">User Class</a><br>
532 Superclass: <a href="#Value"><tt>Value</tt></a><p>
535 The <tt>User</tt> class is the common base class of all LLVM nodes that may
536 refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
537 that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
538 referring to. The <tt>User</tt> class itself is a subclass of
541 The operands of a <tt>User</tt> point directly to the LLVM <a
542 href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
543 Single Assignment (SSA) form, there can only be one definition referred to,
544 allowing this direct connection. This connection provides the use-def
545 information in LLVM.<p>
547 <!-- _______________________________________________________________________ -->
548 </ul><h4><a name="m_User"><hr size=0>Important Public Members of
549 the <tt>User</tt> class</h4><ul>
551 The <tt>User</tt> class exposes the operand list in two ways: through an index
552 access interface and through an iterator based interface.<p>
554 <li><tt>Value *getOperand(unsigned i)</tt><br>
555 <tt>unsigned getNumOperands()</tt><p>
557 These two methods expose the operands of the <tt>User</tt> in a convenient form
558 for direct access.<p>
560 <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand list<br>
561 <tt>User::op_const_iterator</tt>
562 <tt>use_iterator op_begin()</tt>
563 - Get an iterator to the start of the operand list.<br>
564 <tt>use_iterator op_end()</tt>
565 - Get an iterator to the end of the operand list.<p>
567 Together, these methods make up the iterator based interface to the operands of
572 <!-- ======================================================================= -->
573 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
574 <tr><td> </td><td width="100%">
575 <font color="#EEEEFF" face="Georgia,Palatino"><b>
576 <a name="Instruction">The <tt>Instruction</tt> class</a>
577 </b></font></td></tr></table><ul>
580 href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt></b><br>
581 doxygen info: <a href="/doxygen/classInstruction.html">Instruction Class</a><br>
582 Superclasses: <a href="#User"><tt>User</tt></a>, <a
583 href="#Value"><tt>Value</tt></a><p>
585 The <tt>Instruction</tt> class is the common base class for all LLVM
586 instructions. It provides only a few methods, but is a very commonly used
587 class. The primary data tracked by the <tt>Instruction</tt> class itself is the
588 opcode (instruction type) and the parent <a
589 href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
590 into. To represent a specific type of instruction, one of many subclasses of
591 <tt>Instruction</tt> are used.<p>
593 Because the <tt>Instruction</tt> class subclasses the <a
594 href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
595 way as for other <a href="#User"><tt>User</tt></a>s (with the
596 <tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
597 <tt>op_begin()</tt>/<tt>op_end()</tt> methods).<p>
600 <!-- _______________________________________________________________________ -->
601 </ul><h4><a name="m_Instruction"><hr size=0>Important Public Members of
602 the <tt>Instruction</tt> class</h4><ul>
604 <li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt><p>
606 Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that this
607 <tt>Instruction</tt> is embedded into.<p>
609 <li><tt>bool hasSideEffects()</tt><p>
611 Returns true if the instruction has side effects, i.e. it is a <tt>call</tt>,
612 <tt>free</tt>, <tt>invoke</tt>, or <tt>store</tt>.<p>
614 <li><tt>unsigned getOpcode()</tt><p>
616 Returns the opcode for the <tt>Instruction</tt>.<p>
620 \subsection{Subclasses of Instruction :}
622 <li>BinaryOperator : This subclass of Instruction defines a general interface to the all the instructions involvong binary operators in LLVM.
624 <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.
626 <li>TerminatorInst : This subclass of Instructions defines an interface for all instructions that can terminate a BasicBlock.
628 <li> <tt>unsigned getNumSuccessors()</tt>: Returns the number of successors for this terminator instruction.
629 <li><tt>BasicBlock *getSuccessor(unsigned i)</tt>: As the name suggests returns the ith successor BasicBlock.
630 <li><tt>void setSuccessor(unsigned i, BasicBlock *B)</tt>: sets BasicBlock B as the ith succesor to this terminator instruction.
633 <li>PHINode : This represents the PHI instructions in the SSA form.
635 <li><tt> unsigned getNumIncomingValues()</tt>: Returns the number of incoming edges to this PHI node.
636 <li><tt> Value *getIncomingValue(unsigned i)</tt>: Returns the ith incoming Value.
637 <li><tt>void setIncomingValue(unsigned i, Value *V)</tt>: Sets the ith incoming Value as V
638 <li><tt>BasicBlock *getIncomingBlock(unsigned i)</tt>: Returns the Basic Block corresponding to the ith incoming Value.
639 <li><tt> void addIncoming(Value *D, BasicBlock *BB)</tt>:
640 Add an incoming value to the end of the PHI list
641 <li><tt> int getBasicBlockIndex(const BasicBlock *BB) const</tt>:
642 Returns the first index of the specified basic block in the value list for this PHI. Returns -1 if no instance.
644 <li>CastInst : In LLVM all casts have to be done through explicit cast instructions. CastInst defines the interface to the cast instructions.
645 <li>CallInst : This defines an interface to the call instruction in LLVM. ARguments to the function are nothing but operands of the instruction.
647 <li>: <tt>Function *getCalledFunction()</tt>: Returns a handle to the function that is being called by this Function.
649 <li>LoadInst, StoreInst, GetElemPtrInst : These subclasses represent load, store and getelementptr instructions in LLVM.
651 <li><tt>Value * getPointerOperand ()</tt>: Returns the Pointer Operand which is typically the 0th operand.
653 <li>BranchInst : This is a subclass of TerminatorInst and defines the interface for conditional and unconditional branches in LLVM.
655 <li><tt>bool isConditional()</tt>: Returns true if the branch is a conditional branch else returns false
656 <li> <tt>Value *getCondition()</tt>: Returns the condition if it is a conditional branch else returns null.
657 <li> <tt>void setUnconditionalDest(BasicBlock *Dest)</tt>: Changes the current branch to an unconditional one targetting the specified block.
665 <!-- ======================================================================= -->
666 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
667 <tr><td> </td><td width="100%">
668 <font color="#EEEEFF" face="Georgia,Palatino"><b>
669 <a name="BasicBlock">The <tt>BasicBlock</tt> class</a>
670 </b></font></td></tr></table><ul>
673 href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt></b><br>
674 doxygen info: <a href="/doxygen/classBasicBlock.html">BasicBlock Class</a><br>
675 Superclass: <a href="#Value"><tt>Value</tt></a><p>
678 This class represents a single entry multiple exit section of the code, commonly
679 known as a basic block by the compiler community. The <tt>BasicBlock</tt> class
680 maintains a list of <a href="#Instruction"><tt>Instruction</tt></a>s, which form
681 the body of the block. Matching the language definition, the last element of
682 this list of instructions is always a terminator instruction (a subclass of the
683 <a href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).<p>
685 In addition to tracking the list of instructions that make up the block, the
686 <tt>BasicBlock</tt> class also keeps track of the <a
687 href="#Function"><tt>Function</tt></a> that it is embedded into.<p>
689 Note that <tt>BasicBlock</tt>s themselves are <a
690 href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
691 like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
695 <!-- _______________________________________________________________________ -->
696 </ul><h4><a name="m_BasicBlock"><hr size=0>Important Public Members of
697 the <tt>BasicBlock</tt> class</h4><ul>
699 <li><tt>BasicBlock(const std::string &Name = "", <a
700 href="#Function">Function</a> *Parent = 0)</tt><p>
702 The <tt>BasicBlock</tt> constructor is used to create new basic blocks for
703 insertion into a function. The constructor simply takes a name for the new
704 block, and optionally a <a href="#Function"><tt>Function</tt></a> to insert it
705 into. If the <tt>Parent</tt> parameter is specified, the new
706 <tt>BasicBlock</tt> is automatically inserted at the end of the specified <a
707 href="#Function"><tt>Function</tt></a>, if not specified, the BasicBlock must be
708 manually inserted into the <a href="#Function"><tt>Function</tt></a>.<p>
710 <li><tt>BasicBlock::iterator</tt> - Typedef for instruction list iterator<br>
711 <tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
712 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
713 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
715 These methods and typedefs are forwarding functions that have the same semantics
716 as the standard library methods of the same names. These methods expose the
717 underlying instruction list of a basic block in a way that is easy to
718 manipulate. To get the full complement of container operations (including
719 operations to update the list), you must use the <tt>getInstList()</tt>
722 <li><tt>BasicBlock::InstListType &getInstList()</tt><p>
724 This method is used to get access to the underlying container that actually
725 holds the Instructions. This method must be used when there isn't a forwarding
726 function in the <tt>BasicBlock</tt> class for the operation that you would like
727 to perform. Because there are no forwarding functions for "updating"
728 operations, you need to use this if you want to update the contents of a
729 <tt>BasicBlock</tt>.<p>
731 <li><tt><A href="#Function">Function</a> *getParent()</tt><p>
733 Returns a pointer to <a href="#Function"><tt>Function</tt></a> the block is
734 embedded into, or a null pointer if it is homeless.<p>
736 <li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt><p>
738 Returns a pointer to the terminator instruction that appears at the end of the
739 <tt>BasicBlock</tt>. If there is no terminator instruction, or if the last
740 instruction in the block is not a terminator, then a null pointer is
744 <!-- ======================================================================= -->
745 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
746 <tr><td> </td><td width="100%">
747 <font color="#EEEEFF" face="Georgia,Palatino"><b>
748 <a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
749 </b></font></td></tr></table><ul>
752 href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt></b><br>
753 doxygen info: <a href="/doxygen/classGlobalValue.html">GlobalValue Class</a><br>
754 Superclasses: <a href="#User"><tt>User</tt></a>, <a
755 href="#Value"><tt>Value</tt></a><p>
757 Global values (<A href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
758 href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
759 visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
760 Because they are visible at global scope, they are also subject to linking with
761 other globals defined in different translation units. To control the linking
762 process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
763 <tt>GlobalValue</tt>s know whether they have internal or external linkage.<p>
765 If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
766 <tt>static</tt> in C), it is not visible to code outside the current translation
767 unit, and does not participate in linking. If it has external linkage, it is
768 visible to external code, and does participate in linking. In addition to
769 linkage information, <tt>GlobalValue</tt>s keep track of which <a
770 href="#Module"><tt>Module</tt></a> they are currently part of.<p>
772 Because <tt>GlobalValue</tt>s are memory objects, they are always referred to by
773 their address. As such, the <a href="#Type"><tt>Type</tt></a> of a global is
774 always a pointer to its contents. This is explained in the LLVM Language
778 <!-- _______________________________________________________________________ -->
779 </ul><h4><a name="m_GlobalValue"><hr size=0>Important Public Members of
780 the <tt>GlobalValue</tt> class</h4><ul>
782 <li><tt>bool hasInternalLinkage() const</tt><br>
783 <tt>bool hasExternalLinkage() const</tt><br>
784 <tt>void setInternalLinkage(bool HasInternalLinkage)</tt><p>
786 These methods manipulate the linkage characteristics of the
787 <tt>GlobalValue</tt>.<p>
789 <li><tt><a href="#Module">Module</a> *getParent()</tt><p>
791 This returns the <a href="#Module"><tt>Module</tt></a> that the GlobalValue is
792 currently embedded into.<p>
796 <!-- ======================================================================= -->
797 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
798 <tr><td> </td><td width="100%">
799 <font color="#EEEEFF" face="Georgia,Palatino"><b>
800 <a name="Function">The <tt>Function</tt> class</a>
801 </b></font></td></tr></table><ul>
804 href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt></b><br>
805 doxygen info: <a href="/doxygen/classFunction.html">Function Class</a><br>
806 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
807 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
809 The <tt>Function</tt> class represents a single procedure in LLVM. It is
810 actually one of the more complex classes in the LLVM heirarchy because it must
811 keep track of a large amount of data. The <tt>Function</tt> class keeps track
812 of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
813 href="#Argument"><tt>Argument</tt></a>s, and a <a
814 href="#SymbolTable"><tt>SymbolTable</tt></a>.<p>
816 The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most commonly
817 used part of <tt>Function</tt> objects. The list imposes an implicit ordering
818 of the blocks in the function, which indicate how the code will be layed out by
819 the backend. Additionally, the first <a
820 href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
821 <tt>Function</tt>. It is not legal in LLVM explicitly branch to this initial
822 block. There are no implicit exit nodes, and in fact there may be multiple exit
823 nodes from a single <tt>Function</tt>. If the <a
824 href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
825 the <tt>Function</tt> is actually a function declaration: the actual body of the
826 function hasn't been linked in yet.<p>
828 In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
829 <tt>Function</tt> class also keeps track of the list of formal <a
830 href="#Argument"><tt>Argument</tt></a>s that the function receives. This
831 container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
832 nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
833 the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.<p>
835 The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used LLVM
836 feature that is only used when you have to look up a value by name. Aside from
837 that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used internally to
838 make sure that there are not conflicts between the names of <a
839 href="#Instruction"><tt>Instruction</tt></a>s, <a
840 href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
841 href="#Argument"><tt>Argument</tt></a>s in the function body.<p>
844 <!-- _______________________________________________________________________ -->
845 </ul><h4><a name="m_Function"><hr size=0>Important Public Members of
846 the <tt>Function</tt> class</h4><ul>
848 <li><tt>Function(const <a href="#FunctionType">FunctionType</a> *Ty, bool isInternal, const std::string &N = "")</tt><p>
850 Constructor used when you need to create new <tt>Function</tt>s to add the the
851 program. The constructor must specify the type of the function to create and
852 whether or not it should start out with internal or external linkage.<p>
854 <li><tt>bool isExternal()</tt><p>
856 Return whether or not the <tt>Function</tt> has a body defined. If the function
857 is "external", it does not have a body, and thus must be resolved by linking
858 with a function defined in a different translation unit.<p>
861 <li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
862 <tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
863 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
864 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
866 These are forwarding methods that make it easy to access the contents of a
867 <tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
870 <li><tt>Function::BasicBlockListType &getBasicBlockList()</tt><p>
872 Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This is
873 neccesary to use when you need to update the list or perform a complex action
874 that doesn't have a forwarding method.<p>
877 <li><tt>Function::aiterator</tt> - Typedef for the argument list iterator<br>
878 <tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
879 <tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
880 <tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt><p>
882 These are forwarding methods that make it easy to access the contents of a
883 <tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a> list.<p>
885 <li><tt>Function::ArgumentListType &getArgumentList()</tt><p>
887 Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This is
888 neccesary to use when you need to update the list or perform a complex action
889 that doesn't have a forwarding method.<p>
893 <li><tt><a href="#BasicBlock">BasicBlock</a> &getEntryNode()</tt><p>
895 Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
896 function. Because the entry block for the function is always the first block,
897 this returns the first block of the <tt>Function</tt>.<p>
899 <li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
900 <tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt><p>
902 This traverses the <a href="#Type"><tt>Type</tt></a> of the <tt>Function</tt>
903 and returns the return type of the function, or the <a
904 href="#FunctionType"><tt>FunctionType</tt></a> of the actual function.<p>
907 <li><tt>bool hasSymbolTable() const</tt><p>
909 Return true if the <tt>Function</tt> has a symbol table allocated to it and if
910 there is at least one entry in it.<p>
912 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
914 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
915 <tt>Function</tt> or a null pointer if one has not been allocated (because there
916 are no named values in the function).<p>
918 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
920 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
921 <tt>Function</tt> or allocate a new <a
922 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
923 should only be used when adding elements to the <a
924 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
925 not left laying around.<p>
929 <!-- ======================================================================= -->
930 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
931 <tr><td> </td><td width="100%">
932 <font color="#EEEEFF" face="Georgia,Palatino"><b>
933 <a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
934 </b></font></td></tr></table><ul>
937 href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt></b><br>
938 doxygen info: <a href="/doxygen/classGlobalVariable.html">GlobalVariable Class</a><br>
939 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
940 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
942 Global variables are represented with the (suprise suprise)
943 <tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are
944 also subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such
945 are always referenced by their address (global values must live in memory, so
946 their "name" refers to their address). Global variables may have an initial
947 value (which must be a <a href="#Constant"><tt>Constant</tt></a>), and if they
948 have an initializer, they may be marked as "constant" themselves (indicating
949 that their contents never change at runtime).<p>
952 <!-- _______________________________________________________________________ -->
953 </ul><h4><a name="m_GlobalVariable"><hr size=0>Important Public Members of the
954 <tt>GlobalVariable</tt> class</h4><ul>
956 <li><tt>GlobalVariable(const <a href="#Type">Type</a> *Ty, bool isConstant, bool
957 isInternal, <a href="#Constant">Constant</a> *Initializer = 0, const std::string
958 &Name = "")</tt><p>
960 Create a new global variable of the specified type. If <tt>isConstant</tt> is
961 true then the global variable will be marked as unchanging for the program, and
962 if <tt>isInternal</tt> is true the resultant global variable will have internal
963 linkage. Optionally an initializer and name may be specified for the global variable as well.<p>
966 <li><tt>bool isConstant() const</tt><p>
968 Returns true if this is a global variable is known not to be modified at
972 <li><tt>bool hasInitializer()</tt><p>
974 Returns true if this <tt>GlobalVariable</tt> has an intializer.<p>
977 <li><tt><a href="#Constant">Constant</a> *getInitializer()</tt><p>
979 Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal to call
980 this method if there is no initializer.<p>
983 <!-- ======================================================================= -->
984 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
985 <tr><td> </td><td width="100%">
986 <font color="#EEEEFF" face="Georgia,Palatino"><b>
987 <a name="Module">The <tt>Module</tt> class</a>
988 </b></font></td></tr></table><ul>
991 href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt></b><br>
992 doxygen info: <a href="/doxygen/classModule.html">Module Class</a><p>
994 The <tt>Module</tt> class represents the top level structure present in LLVM
995 programs. An LLVM module is effectively either a translation unit of the
996 original program or a combination of several translation units merged by the
997 linker. The <tt>Module</tt> class keeps track of a list of <a
998 href="#Function"><tt>Function</tt></a>s, a list of <a
999 href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
1000 href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
1001 helpful member functions that try to make common operations easy.<p>
1004 <!-- _______________________________________________________________________ -->
1005 </ul><h4><a name="m_Module"><hr size=0>Important Public Members of the
1006 <tt>Module</tt> class</h4><ul>
1008 <li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
1009 <tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
1010 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
1011 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
1013 These are forwarding methods that make it easy to access the contents of a
1014 <tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
1017 <li><tt>Module::FunctionListType &getFunctionList()</tt><p>
1019 Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
1020 neccesary to use when you need to update the list or perform a complex action
1021 that doesn't have a forwarding method.<p>
1023 <!-- Global Variable -->
1026 <li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
1027 <tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
1028 <tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
1029 <tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt><p>
1031 These are forwarding methods that make it easy to access the contents of a
1032 <tt>Module</tt> object's <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>
1035 <li><tt>Module::GlobalListType &getGlobalList()</tt><p>
1037 Returns the list of <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s.
1038 This is neccesary to use when you need to update the list or perform a complex
1039 action that doesn't have a forwarding method.<p>
1042 <!-- Symbol table stuff -->
1045 <li><tt>bool hasSymbolTable() const</tt><p>
1047 Return true if the <tt>Module</tt> has a symbol table allocated to it and if
1048 there is at least one entry in it.<p>
1050 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
1052 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1053 <tt>Module</tt> or a null pointer if one has not been allocated (because there
1054 are no named values in the function).<p>
1056 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
1058 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1059 <tt>Module</tt> or allocate a new <a
1060 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
1061 should only be used when adding elements to the <a
1062 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
1063 not left laying around.<p>
1066 <!-- Convenience methods -->
1069 <li><tt><a href="#Function">Function</a> *getFunction(const std::string &Name, const <a href="#FunctionType">FunctionType</a> *Ty)</tt><p>
1071 Look up the specified function in the <tt>Module</tt> <a
1072 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
1076 <li><tt><a href="#Function">Function</a> *getOrInsertFunction(const std::string
1077 &Name, const <a href="#FunctionType">FunctionType</a> *T)</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, add an
1081 external declaration for the function and return it.<p>
1084 <li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt><p>
1086 If there is at least one entry in the <a
1087 href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
1088 href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
1092 <li><tt>bool addTypeName(const std::string &Name, const <a href="#Type">Type</a>
1095 Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a> mapping
1096 <tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this name, true
1097 is returned and the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is not
1101 <!-- ======================================================================= -->
1102 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1103 <tr><td> </td><td width="100%">
1104 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1105 <a name="Constant">The <tt>Constant</tt> class and subclasses</a>
1106 </b></font></td></tr></table><ul>
1108 Constant represents a base class for different types of constants. It is
1109 subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
1110 ConstantArray etc for representing the various types of Constants.<p>
1113 <!-- _______________________________________________________________________ -->
1114 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1116 <li><tt>bool isConstantExpr()</tt>: Returns true if it is a ConstantExpr
1121 \subsection{Important Subclasses of Constant}
1123 <li>ConstantSInt : This subclass of Constant represents a signed integer constant.
1125 <li><tt>int64_t getValue () const</tt>: Returns the underlying value of this constant.
1127 <li>ConstantUInt : This class represents an unsigned integer.
1129 <li><tt>uint64_t getValue () const</tt>: Returns the underlying value of this constant.
1131 <li>ConstantFP : This class represents a floating point constant.
1133 <li><tt>double getValue () const</tt>: Returns the underlying value of this constant.
1135 <li>ConstantBool : This represents a boolean constant.
1137 <li><tt>bool getValue () const</tt>: Returns the underlying value of this constant.
1139 <li>ConstantArray : This represents a constant array.
1141 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1143 <li>ConstantStruct : This represents a constant struct.
1145 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1147 <li>ConstantPointerRef : This represents a constant pointer value that is initialized to point to a global value, which lies at a constant fixed address.
1149 <li><tt>GlobalValue *getValue()</tt>: Returns the global value to which this pointer is pointing to.
1154 <!-- ======================================================================= -->
1155 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1156 <tr><td> </td><td width="100%">
1157 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1158 <a name="Type">The <tt>Type</tt> class and Derived Types</a>
1159 </b></font></td></tr></table><ul>
1161 Type as noted earlier is also a subclass of a Value class. Any primitive
1162 type (like int, short etc) in LLVM is an instance of Type Class. All
1163 other types are instances of subclasses of type like FunctionType,
1164 ArrayType etc. DerivedType is the interface for all such dervied types
1165 including FunctionType, ArrayType, PointerType, StructType. Types can have
1166 names. They can be recursive (StructType). There exists exactly one instance
1167 of any type structure at a time. This allows using pointer equality of Type *s for comparing types.
1169 <!-- _______________________________________________________________________ -->
1170 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1172 <li><tt>PrimitiveID getPrimitiveID () const</tt>: Returns the base type of the type.
1173 <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.
1174 <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.
1175 <li><tt> bool isInteger () const</tt>: Equilivent to isSigned() || isUnsigned(), but with only a single virtual function invocation.
1176 <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.
1178 <li><tt>bool isFloatingPoint ()</tt>: Return true if this is one of the two floating point types.
1179 <li><tt>bool isRecursive () const</tt>: Returns rue if the type graph contains a cycle.
1180 <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.
1181 <li><tt>bool isPrimitiveType () const</tt>: Returns true if it is a primitive type.
1182 <li><tt>bool isDerivedType () const</tt>: Returns true if it is a derived type.
1183 <li><tt>const Type * getContainedType (unsigned i) const</tt>:
1184 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.
1185 <li><tt>unsigned getNumContainedTypes () const</tt>: Return the number of types in the derived type.
1189 \subsection{Derived Types}
1191 <li>SequentialType : This is subclassed by ArrayType and PointerType
1193 <li><tt>const Type * getElementType () const</tt>: Returns the type of each of the elements in the sequential type.
1195 <li>ArrayType : This is a subclass of SequentialType and defines interface for array types.
1197 <li><tt>unsigned getNumElements () const</tt>: Returns the number of elements in the array.
1199 <li>PointerType : Subclass of SequentialType for pointer types.
1200 <li>StructType : subclass of DerivedTypes for struct types
1201 <li>FunctionType : subclass of DerivedTypes for function types.
1204 <li><tt>bool isVarArg () const</tt>: Returns true if its a vararg function
1205 <li><tt> const Type * getReturnType () const</tt>: Returns the return type of the function.
1206 <li><tt> const ParamTypes &getParamTypes () const</tt>: Returns a vector of parameter types.
1207 <li><tt>const Type * getParamType (unsigned i)</tt>: Returns the type of the ith parameter.
1208 <li><tt> const unsigned getNumParams () const</tt>: Returns the number of formal parameters.
1215 <!-- ======================================================================= -->
1216 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1217 <tr><td> </td><td width="100%">
1218 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1219 <a name="Argument">The <tt>Argument</tt> class</a>
1220 </b></font></td></tr></table><ul>
1222 This subclass of Value defines the interface for incoming formal arguments to a
1223 function. A Function maitanis a list of its formal arguments. An argument has a
1224 pointer to the parent Function.
1229 <!-- *********************************************************************** -->
1231 <!-- *********************************************************************** -->
1234 <address>By: <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
1235 <a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
1236 <!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
1237 <!-- hhmts start -->
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