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6 <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
7 <tr><td> <font size=+3 color="#EEEEFF" face="Georgia,Palatino,Times,Roman"><b>LLVM Programmer's Manual</b></font></td>
11 <li><a href="#introduction">Introduction</a>
12 <li><a href="#general">General Information</a>
14 <li><a href="#stl">The C++ Standard Template Library</a>
15 <li>The isa<>, cast<> and dyn_cast<> templates
17 <li><a href="#common">Helpful Hints for Common Operations</a>
19 <li><a href="#inspection">Basic Inspection and Traversal Routines</a>
21 <li><a href="#iterate_function">Iterating over the <tt>BasicBlock</tt>s
22 in a <tt>Function</tt></a>
23 <li><a href="#iterate_basicblock">Iterating over the <tt>Instruction</tt>s
24 in a <tt>BasicBlock</tt></a>
25 <li><a href="#iterate_convert">Turning an iterator into a class
27 <li><a href="#iterate_complex">Finding call sites: a more complex
30 <li><a href="#simplechanges">Making simple changes</a>
32 <li>Creating and inserting new <tt>Instruction</tt>s
33 <li>Deleting <tt>Instruction</tt>s
34 <li>Replacing an <tt>Instruction</tt> with another <tt>Value</tt>
37 <li>Working with the Control Flow Graph
39 <li>Accessing predecessors and successors of a <tt>BasicBlock</tt>
46 <li>isa<>, cast<>, and dyn_cast<> templates
48 <li>The general graph API
49 <li>The <tt>InstVisitor</tt> template
51 <li>The <tt>Statistic</tt> template
55 <li>Useful related topics
57 <li>The <tt>-time-passes</tt> option
58 <li>How to use the LLVM Makefile system
59 <li>How to write a regression test
64 <li><a href="#coreclasses">The Core LLVM Class Hierarchy Reference</a>
66 <li><a href="#Value">The <tt>Value</tt> class</a>
68 <li><a href="#User">The <tt>User</tt> class</a>
70 <li><a href="#Instruction">The <tt>Instruction</tt> class</a>
75 <li><a href="#GlobalValue">The <tt>GlobalValue</tt> class</a>
77 <li><a href="#BasicBlock">The <tt>BasicBlock</tt> class</a>
78 <li><a href="#Function">The <tt>Function</tt> class</a>
79 <li><a href="#GlobalVariable">The <tt>GlobalVariable</tt> class</a>
81 <li><a href="#Module">The <tt>Module</tt> class</a>
82 <li><a href="#Constant">The <tt>Constant</tt> class</a>
88 <li><a href="#Type">The <tt>Type</tt> class</a>
89 <li><a href="#Argument">The <tt>Argument</tt> class</a>
91 <li>The <tt>SymbolTable</tt> class
92 <li>The <tt>ilist</tt> and <tt>iplist</tt> classes
94 <li>Creating, inserting, moving and deleting from LLVM lists
96 <li>Important iterator invalidation semantics to be aware of
99 <p><b>Written by <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a>
100 <a href="mailto:sabre@nondot.org">Chris Lattner</a>, and
101 <a href="mailto:jstanley@cs.uiuc.edu">Joel Stanley</a></b><p>
105 <!-- *********************************************************************** -->
106 <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
107 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
108 <a name="introduction">Introduction
109 </b></font></td></tr></table><ul>
110 <!-- *********************************************************************** -->
112 This document is meant to highlight some of the important classes and interfaces
113 available in the LLVM source-base. This manual is not intended to explain what
114 LLVM is, how it works, and what LLVM code looks like. It assumes that you know
115 the basics of LLVM and are interested in writing transformations or otherwise
116 analyzing or manipulating the code.<p>
118 This document should get you oriented so that you can find your way in the
119 continuously growing source code that makes up the LLVM infrastructure. Note
120 that this manual is not intended to serve as a replacement for reading the
121 source code, so if you think there should be a method in one of these classes to
122 do something, but it's not listed, check the source. Links to the <a
123 href="/doxygen/">doxygen</a> sources are provided to make this as easy as
126 The first section of this document describes general information that is useful
127 to know when working in the LLVM infrastructure, and the second describes the
128 Core LLVM classes. In the future this manual will be extended with information
129 describing how to use extension libraries, such as dominator information, CFG
130 traversal routines, and useful utilities like the <tt><a
131 href="/doxygen/InstVisitor_8h-source.html">InstVisitor</a></tt> template.<p>
134 <!-- *********************************************************************** -->
135 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
136 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
137 <a name="general">General Information
138 </b></font></td></tr></table><ul>
139 <!-- *********************************************************************** -->
141 This section contains general information that is useful if you are working in
142 the LLVM source-base, but that isn't specific to any particular API.<p>
145 <!-- ======================================================================= -->
146 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
147 <tr><td> </td><td width="100%">
148 <font color="#EEEEFF" face="Georgia,Palatino"><b>
149 <a name="stl">The C++ Standard Template Library</a>
150 </b></font></td></tr></table><ul>
152 LLVM makes heavy use of the C++ Standard Template Library (STL), perhaps much
153 more than you are used to, or have seen before. Because of this, you might want
154 to do a little background reading in the techniques used and capabilities of the
155 library. There are many good pages that discuss the STL, and several books on
156 the subject that you can get, so it will not be discussed in this document.<p>
158 Here are some useful links:<p>
160 <li><a href="http://www.dinkumware.com/htm_cpl/index.html">Dinkumware C++
161 Library reference</a> - an excellent reference for the STL and other parts of
162 the standard C++ library.<br>
164 <li><a href="http://www.parashift.com/c++-faq-lite/">C++ Frequently Asked
167 <li><a href="http://www.sgi.com/tech/stl/">SGI's STL Programmer's Guide</a> -
169 href="http://www.sgi.com/tech/stl/stl_introduction.html">Introduction to the
172 <li><a href="http://www.research.att.com/~bs/C++.html">Bjarne Stroustrup's C++
177 You are also encouraged to take a look at the <a
178 href="CodingStandards.html">LLVM Coding Standards</a> guide which focuses on how
179 to write maintainable code more than where to put your curly braces.<p>
183 <!-- *********************************************************************** -->
184 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
185 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
186 <a name="common">Helpful Hints for Common Operations
187 </b></font></td></tr></table><ul>
188 <!-- *********************************************************************** -->
190 This section describes how to perform some very simple transformations of LLVM
191 code. This is meant to give examples of common idioms used, showing the
192 practical side of LLVM transformations.<p>
194 Because this is a "how-to" section, you should also read about the main classes
195 that you will be working with. The <a href="#coreclasses">Core LLVM Class
196 Hierarchy Reference</a> contains details and descriptions of the main classes
197 that you should know about.<p>
199 <!-- NOTE: this section should be heavy on example code -->
202 <!-- ======================================================================= -->
203 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
204 <tr><td> </td><td width="100%">
205 <font color="#EEEEFF" face="Georgia,Palatino"><b>
206 <a name="inspection">Basic Inspection and Traversal Routines</a>
207 </b></font></td></tr></table><ul>
210 <!-- LLVM has heirarchical representation: Module, Function, BasicBlock,
211 Instruction. Common patterns for all levels. -->
213 <!-- _______________________________________________________________________ -->
214 </ul><h4><a name="iterate_function"><hr size=0>Iterating over the
215 <tt>BasicBlock</tt>s in a <tt>Function</tt> </h4><ul>
217 It's quite common to have a <tt>Function</tt> instance that you'd like
218 to transform in some way; in particular, you'd like to manipulate its
219 <tt>BasicBlock</tt>s. To facilitate this, you'll need to iterate over
220 all of the <tt>BasicBlock</tt>s that constitute the <tt>Function</tt>.
221 The following is an example that prints the name of a
222 <tt>BasicBlock</tt> and the number of <tt>Instruction</tt>s it
226 // func is a pointer to a Function instance
227 for(Function::iterator i = func->begin(), e = func->end(); i != e; ++i) {
229 // print out the name of the basic block if it has one, and then the
230 // number of instructions that it contains
232 cerr << "Basic block (name=" << i->getName() << ") has "
233 << i->size() << " instructions.\n";
237 Note that i can be used as if it were a pointer for the purposes of
238 invoking member functions of the <tt>Instruction</tt> class. This is
239 because the indirection operator is overloaded for the iterator
240 classes. In the above code, the expression <tt>i->size()</tt> is
241 exactly equivalent to <tt>(*i).size()</tt> just like you'd expect.
243 <!-- _______________________________________________________________________ -->
244 </ul><h4><a name="iterate_basicblock"><hr size=0>Iterating over the
245 <tt>Instruction</tt>s in a <tt>BasicBlock</tt> </h4><ul>
247 Just like when dealing with <tt>BasicBlock</tt>s in <tt>Function</tt>s, it's
248 easy to iterate over the individual instructions that make up
249 <tt>BasicBlock</tt>s. Here's a code snippet that prints out each instruction in
250 a <tt>BasicBlock</tt>:
253 // blk is a pointer to a BasicBlock instance
254 for(BasicBlock::iterator i = blk->begin(), e = blk->end(); i != e; ++i) {
255 // the next statement works since operator<<(ostream&,...)
256 // is overloaded for Instruction&
262 However, this isn't really the best way to print out the contents of a
263 <tt>BasicBlock</tt>! Since the ostream operators are overloaded for
264 virtually anything you'll care about, you could have just invoked the
265 print routine on the basic block itself: <tt>cerr << blk <<
266 endl;</tt>. You might expect this to print out the pointer value of
267 blk, but operator<< is overloaded for BasicBlock* as well: if you
268 really want to print the pointer value explicitly, you'll have to
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;
324 Of course, this example is strictly pedagogical, because it'd be
325 better to do something like
327 <pre>if(inst->getNext()) cerr << inst->getNext() << endl;</pre>
330 <!-- dereferenced iterator = Class &
331 iterators have converting constructor for 'Class *'
332 iterators automatically convert to 'Class *' except in dyn_cast<> case
336 _______________________________________________________________________
337 --> </ul><h4><a name="iterate_complex"><hr size=0>Finding call sites:
338 a slightly more complex example
341 Say that you're writing a FunctionPass and would like to count all the
342 locations in the entire module (that is, across every <tt>Function</tt>)
343 where a certain function named foo (that takes an int and returns an
344 int) is called. As you'll learn later, you may want to use an
345 <tt>InstVisitor</tt> to accomplish this in a much more straightforward
346 manner, but this example will allow us to explore how you'd do it if
347 you didn't have <tt>InstVisitor</tt> around. In pseudocode, this is
351 initialize callCounter to zero
352 for each Function f in the Module
353 for each BasicBlock b in f
354 for each Instruction i in b
355 if(i is a CallInst and foo is the function it calls)
356 increment callCounter
359 And the actual code is (remember, since we're writing a
360 <tt>FunctionPass</tt> our <tt>FunctionPass</tt>-derived class simply
361 has to override the <tt>runOnFunction</tt> method...):
365 // Assume callCounter is a private member of the pass class being written,
366 // and has been initialized in the pass class constructor.
368 virtual runOnFunction(Function& F) {
370 // Remember, we assumed that the signature of foo was "int foo(int)";
371 // the first thing we'll do is grab the pointer to that function (as a
372 // Function*) so we can use it later when we're examining the
373 // parameters of a CallInst. All of the code before the call to
374 // Module::getOrInsertFunction() is in preparation to do symbol-table
375 // to find the function pointer.
377 vector<const Type*> params;
378 params.push_back(Type::IntTy);
379 const FunctionType* fooType = FunctionType::get(Type::IntTy, params);
380 Function* foo = F.getParent()->getOrInsertFunction("foo", fooType);
382 // Start iterating and (as per the pseudocode), increment callCounter.
384 for(Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
385 for(BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {
386 if(CallInst* callInst = dyn_cast<CallInst>(&*inst)) {
387 // we know we've encountered a call instruction, so we
388 // need to determine if it's a call to foo or not
390 if(callInst->getCalledFunction() == foo)
398 We could then print out the value of callCounter (if we wanted to)
399 inside the doFinalization method of our FunctionPass.
402 <!-- ======================================================================= -->
403 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
404 <tr><td> </td><td width="100%">
405 <font color="#EEEEFF" face="Georgia,Palatino"><b>
406 <a name="simplechanges">Making simple changes</a>
407 </b></font></td></tr></table><ul>
409 <!-- Value::replaceAllUsesWith
410 User::replaceUsesOfWith
411 Point out: include/llvm/Transforms/Utils/
412 especially BasicBlockUtils.h with:
413 ReplaceInstWithValue, ReplaceInstWithInst
418 <!-- *********************************************************************** -->
419 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
420 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
421 <a name="coreclasses">The Core LLVM Class Hierarchy Reference
422 </b></font></td></tr></table><ul>
423 <!-- *********************************************************************** -->
425 The Core LLVM classes are the primary means of representing the program being
426 inspected or transformed. The core LLVM classes are defined in header files in
427 the <tt>include/llvm/</tt> directory, and implemented in the <tt>lib/VMCore</tt>
431 <!-- ======================================================================= -->
432 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
433 <tr><td> </td><td width="100%">
434 <font color="#EEEEFF" face="Georgia,Palatino"><b>
435 <a name="Value">The <tt>Value</tt> class</a>
436 </b></font></td></tr></table><ul>
438 <tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt></b><br>
439 doxygen info: <a href="/doxygen/classValue.html">Value Class</a><p>
442 The <tt>Value</tt> class is the most important class in LLVM Source base. It
443 represents a typed value that may be used (among other things) as an operand to
444 an instruction. There are many different types of <tt>Value</tt>s, such as <a
445 href="#Constant"><tt>Constant</tt></a>s, <a
446 href="#Argument"><tt>Argument</tt></a>s, and even <a
447 href="#Instruction"><tt>Instruction</tt></a>s and <a
448 href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.<p>
450 A particular <tt>Value</tt> may be used many times in the LLVM representation
451 for a program. For example, an incoming argument to a function (represented
452 with an instance of the <a href="#Argument">Argument</a> class) is "used" by
453 every instruction in the function that references the argument. To keep track
454 of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
455 href="#User"><tt>User</tt></a>s that is using it (the <a
456 href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
457 graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
458 def-use information in the program, and is accessible through the <tt>use_</tt>*
459 methods, shown below.<p>
461 Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed, and
462 this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
463 method. <a name="#nameWarning">In addition, all LLVM values can be named. The
464 "name" of the <tt>Value</tt> is symbolic string printed in the LLVM code:<p>
467 %<b>foo</b> = add int 1, 2
470 The name of this instruction is "foo". <b>NOTE</b> that the name of any value
471 may be missing (an empty string), so names should <b>ONLY</b> be used for
472 debugging (making the source code easier to read, debugging printouts), they
473 should not be used to keep track of values or map between them. For this
474 purpose, use a <tt>std::map</tt> of pointers to the <tt>Value</tt> itself
477 One important aspect of LLVM is that there is no distinction between an SSA
478 variable and the operation that produces it. Because of this, any reference to
479 the value produced by an instruction (or the value available as an incoming
480 argument, for example) is represented as a direct pointer to the class that
481 represents this value. Although this may take some getting used to, it
482 simplifies the representation and makes it easier to manipulate.<p>
485 <!-- _______________________________________________________________________ -->
486 </ul><h4><a name="m_Value"><hr size=0>Important Public Members of
487 the <tt>Value</tt> class</h4><ul>
489 <li><tt>Value::use_iterator</tt> - Typedef for iterator over the use-list<br>
490 <tt>Value::use_const_iterator</tt>
491 - Typedef for const_iterator over the use-list<br>
492 <tt>unsigned use_size()</tt> - Returns the number of users of the value.<br>
493 <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
494 <tt>use_iterator use_begin()</tt>
495 - Get an iterator to the start of the use-list.<br>
496 <tt>use_iterator use_end()</tt>
497 - Get an iterator to the end of the use-list.<br>
498 <tt><a href="#User">User</a> *use_back()</tt>
499 - Returns the last element in the list.<p>
501 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>
503 <li><tt><a href="#Type">Type</a> *getType() const</tt><p>
504 This method returns the Type of the Value.
506 <li><tt>bool hasName() const</tt><br>
507 <tt>std::string getName() const</tt><br>
508 <tt>void setName(const std::string &Name)</tt><p>
510 This family of methods is used to access and assign a name to a <tt>Value</tt>,
511 be aware of the <a href="#nameWarning">precaution above</a>.<p>
514 <li><tt>void replaceAllUsesWith(Value *V)</tt><p>
516 This method traverses the use list of a <tt>Value</tt> changing all <a
517 href="#User"><tt>User</tt>'s</a> of the current value to refer to "<tt>V</tt>"
518 instead. For example, if you detect that an instruction always produces a
519 constant value (for example through constant folding), you can replace all uses
520 of the instruction with the constant like this:<p>
523 Inst->replaceAllUsesWith(ConstVal);
528 <!-- ======================================================================= -->
529 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
530 <tr><td> </td><td width="100%">
531 <font color="#EEEEFF" face="Georgia,Palatino"><b>
532 <a name="User">The <tt>User</tt> class</a>
533 </b></font></td></tr></table><ul>
535 <tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt></b><br>
536 doxygen info: <a href="/doxygen/classUser.html">User Class</a><br>
537 Superclass: <a href="#Value"><tt>Value</tt></a><p>
540 The <tt>User</tt> class is the common base class of all LLVM nodes that may
541 refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
542 that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
543 referring to. The <tt>User</tt> class itself is a subclass of
546 The operands of a <tt>User</tt> point directly to the LLVM <a
547 href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
548 Single Assignment (SSA) form, there can only be one definition referred to,
549 allowing this direct connection. This connection provides the use-def
550 information in LLVM.<p>
552 <!-- _______________________________________________________________________ -->
553 </ul><h4><a name="m_User"><hr size=0>Important Public Members of
554 the <tt>User</tt> class</h4><ul>
556 The <tt>User</tt> class exposes the operand list in two ways: through an index
557 access interface and through an iterator based interface.<p>
559 <li><tt>Value *getOperand(unsigned i)</tt><br>
560 <tt>unsigned getNumOperands()</tt><p>
562 These two methods expose the operands of the <tt>User</tt> in a convenient form
563 for direct access.<p>
565 <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand list<br>
566 <tt>User::op_const_iterator</tt>
567 <tt>use_iterator op_begin()</tt>
568 - Get an iterator to the start of the operand list.<br>
569 <tt>use_iterator op_end()</tt>
570 - Get an iterator to the end of the operand list.<p>
572 Together, these methods make up the iterator based interface to the operands of
577 <!-- ======================================================================= -->
578 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
579 <tr><td> </td><td width="100%">
580 <font color="#EEEEFF" face="Georgia,Palatino"><b>
581 <a name="Instruction">The <tt>Instruction</tt> class</a>
582 </b></font></td></tr></table><ul>
585 href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt></b><br>
586 doxygen info: <a href="/doxygen/classInstruction.html">Instruction Class</a><br>
587 Superclasses: <a href="#User"><tt>User</tt></a>, <a
588 href="#Value"><tt>Value</tt></a><p>
590 The <tt>Instruction</tt> class is the common base class for all LLVM
591 instructions. It provides only a few methods, but is a very commonly used
592 class. The primary data tracked by the <tt>Instruction</tt> class itself is the
593 opcode (instruction type) and the parent <a
594 href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
595 into. To represent a specific type of instruction, one of many subclasses of
596 <tt>Instruction</tt> are used.<p>
598 Because the <tt>Instruction</tt> class subclasses the <a
599 href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
600 way as for other <a href="#User"><tt>User</tt></a>s (with the
601 <tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
602 <tt>op_begin()</tt>/<tt>op_end()</tt> methods).<p>
605 <!-- _______________________________________________________________________ -->
606 </ul><h4><a name="m_Instruction"><hr size=0>Important Public Members of
607 the <tt>Instruction</tt> class</h4><ul>
609 <li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt><p>
611 Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that this
612 <tt>Instruction</tt> is embedded into.<p>
614 <li><tt>bool hasSideEffects()</tt><p>
616 Returns true if the instruction has side effects, i.e. it is a <tt>call</tt>,
617 <tt>free</tt>, <tt>invoke</tt>, or <tt>store</tt>.<p>
619 <li><tt>unsigned getOpcode()</tt><p>
621 Returns the opcode for the <tt>Instruction</tt>.<p>
625 \subsection{Subclasses of Instruction :}
627 <li>BinaryOperator : This subclass of Instruction defines a general interface to the all the instructions involvong binary operators in LLVM.
629 <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.
631 <li>TerminatorInst : This subclass of Instructions defines an interface for all instructions that can terminate a BasicBlock.
633 <li> <tt>unsigned getNumSuccessors()</tt>: Returns the number of successors for this terminator instruction.
634 <li><tt>BasicBlock *getSuccessor(unsigned i)</tt>: As the name suggests returns the ith successor BasicBlock.
635 <li><tt>void setSuccessor(unsigned i, BasicBlock *B)</tt>: sets BasicBlock B as the ith succesor to this terminator instruction.
638 <li>PHINode : This represents the PHI instructions in the SSA form.
640 <li><tt> unsigned getNumIncomingValues()</tt>: Returns the number of incoming edges to this PHI node.
641 <li><tt> Value *getIncomingValue(unsigned i)</tt>: Returns the ith incoming Value.
642 <li><tt>void setIncomingValue(unsigned i, Value *V)</tt>: Sets the ith incoming Value as V
643 <li><tt>BasicBlock *getIncomingBlock(unsigned i)</tt>: Returns the Basic Block corresponding to the ith incoming Value.
644 <li><tt> void addIncoming(Value *D, BasicBlock *BB)</tt>:
645 Add an incoming value to the end of the PHI list
646 <li><tt> int getBasicBlockIndex(const BasicBlock *BB) const</tt>:
647 Returns the first index of the specified basic block in the value list for this PHI. Returns -1 if no instance.
649 <li>CastInst : In LLVM all casts have to be done through explicit cast instructions. CastInst defines the interface to the cast instructions.
650 <li>CallInst : This defines an interface to the call instruction in LLVM. ARguments to the function are nothing but operands of the instruction.
652 <li>: <tt>Function *getCalledFunction()</tt>: Returns a handle to the function that is being called by this Function.
654 <li>LoadInst, StoreInst, GetElemPtrInst : These subclasses represent load, store and getelementptr instructions in LLVM.
656 <li><tt>Value * getPointerOperand ()</tt>: Returns the Pointer Operand which is typically the 0th operand.
658 <li>BranchInst : This is a subclass of TerminatorInst and defines the interface for conditional and unconditional branches in LLVM.
660 <li><tt>bool isConditional()</tt>: Returns true if the branch is a conditional branch else returns false
661 <li> <tt>Value *getCondition()</tt>: Returns the condition if it is a conditional branch else returns null.
662 <li> <tt>void setUnconditionalDest(BasicBlock *Dest)</tt>: Changes the current branch to an unconditional one targetting the specified block.
670 <!-- ======================================================================= -->
671 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
672 <tr><td> </td><td width="100%">
673 <font color="#EEEEFF" face="Georgia,Palatino"><b>
674 <a name="BasicBlock">The <tt>BasicBlock</tt> class</a>
675 </b></font></td></tr></table><ul>
678 href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt></b><br>
679 doxygen info: <a href="/doxygen/classBasicBlock.html">BasicBlock Class</a><br>
680 Superclass: <a href="#Value"><tt>Value</tt></a><p>
683 This class represents a single entry multiple exit section of the code, commonly
684 known as a basic block by the compiler community. The <tt>BasicBlock</tt> class
685 maintains a list of <a href="#Instruction"><tt>Instruction</tt></a>s, which form
686 the body of the block. Matching the language definition, the last element of
687 this list of instructions is always a terminator instruction (a subclass of the
688 <a href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).<p>
690 In addition to tracking the list of instructions that make up the block, the
691 <tt>BasicBlock</tt> class also keeps track of the <a
692 href="#Function"><tt>Function</tt></a> that it is embedded into.<p>
694 Note that <tt>BasicBlock</tt>s themselves are <a
695 href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
696 like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
700 <!-- _______________________________________________________________________ -->
701 </ul><h4><a name="m_BasicBlock"><hr size=0>Important Public Members of
702 the <tt>BasicBlock</tt> class</h4><ul>
704 <li><tt>BasicBlock(const std::string &Name = "", <a
705 href="#Function">Function</a> *Parent = 0)</tt><p>
707 The <tt>BasicBlock</tt> constructor is used to create new basic blocks for
708 insertion into a function. The constructor simply takes a name for the new
709 block, and optionally a <a href="#Function"><tt>Function</tt></a> to insert it
710 into. If the <tt>Parent</tt> parameter is specified, the new
711 <tt>BasicBlock</tt> is automatically inserted at the end of the specified <a
712 href="#Function"><tt>Function</tt></a>, if not specified, the BasicBlock must be
713 manually inserted into the <a href="#Function"><tt>Function</tt></a>.<p>
715 <li><tt>BasicBlock::iterator</tt> - Typedef for instruction list iterator<br>
716 <tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
717 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
718 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
720 These methods and typedefs are forwarding functions that have the same semantics
721 as the standard library methods of the same names. These methods expose the
722 underlying instruction list of a basic block in a way that is easy to
723 manipulate. To get the full complement of container operations (including
724 operations to update the list), you must use the <tt>getInstList()</tt>
727 <li><tt>BasicBlock::InstListType &getInstList()</tt><p>
729 This method is used to get access to the underlying container that actually
730 holds the Instructions. This method must be used when there isn't a forwarding
731 function in the <tt>BasicBlock</tt> class for the operation that you would like
732 to perform. Because there are no forwarding functions for "updating"
733 operations, you need to use this if you want to update the contents of a
734 <tt>BasicBlock</tt>.<p>
736 <li><tt><A href="#Function">Function</a> *getParent()</tt><p>
738 Returns a pointer to <a href="#Function"><tt>Function</tt></a> the block is
739 embedded into, or a null pointer if it is homeless.<p>
741 <li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt><p>
743 Returns a pointer to the terminator instruction that appears at the end of the
744 <tt>BasicBlock</tt>. If there is no terminator instruction, or if the last
745 instruction in the block is not a terminator, then a null pointer is
749 <!-- ======================================================================= -->
750 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
751 <tr><td> </td><td width="100%">
752 <font color="#EEEEFF" face="Georgia,Palatino"><b>
753 <a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
754 </b></font></td></tr></table><ul>
757 href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt></b><br>
758 doxygen info: <a href="/doxygen/classGlobalValue.html">GlobalValue Class</a><br>
759 Superclasses: <a href="#User"><tt>User</tt></a>, <a
760 href="#Value"><tt>Value</tt></a><p>
762 Global values (<A href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
763 href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
764 visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
765 Because they are visible at global scope, they are also subject to linking with
766 other globals defined in different translation units. To control the linking
767 process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
768 <tt>GlobalValue</tt>s know whether they have internal or external linkage.<p>
770 If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
771 <tt>static</tt> in C), it is not visible to code outside the current translation
772 unit, and does not participate in linking. If it has external linkage, it is
773 visible to external code, and does participate in linking. In addition to
774 linkage information, <tt>GlobalValue</tt>s keep track of which <a
775 href="#Module"><tt>Module</tt></a> they are currently part of.<p>
777 Because <tt>GlobalValue</tt>s are memory objects, they are always referred to by
778 their address. As such, the <a href="#Type"><tt>Type</tt></a> of a global is
779 always a pointer to its contents. This is explained in the LLVM Language
783 <!-- _______________________________________________________________________ -->
784 </ul><h4><a name="m_GlobalValue"><hr size=0>Important Public Members of
785 the <tt>GlobalValue</tt> class</h4><ul>
787 <li><tt>bool hasInternalLinkage() const</tt><br>
788 <tt>bool hasExternalLinkage() const</tt><br>
789 <tt>void setInternalLinkage(bool HasInternalLinkage)</tt><p>
791 These methods manipulate the linkage characteristics of the
792 <tt>GlobalValue</tt>.<p>
794 <li><tt><a href="#Module">Module</a> *getParent()</tt><p>
796 This returns the <a href="#Module"><tt>Module</tt></a> that the GlobalValue is
797 currently embedded into.<p>
801 <!-- ======================================================================= -->
802 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
803 <tr><td> </td><td width="100%">
804 <font color="#EEEEFF" face="Georgia,Palatino"><b>
805 <a name="Function">The <tt>Function</tt> class</a>
806 </b></font></td></tr></table><ul>
809 href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt></b><br>
810 doxygen info: <a href="/doxygen/classFunction.html">Function Class</a><br>
811 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
812 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
814 The <tt>Function</tt> class represents a single procedure in LLVM. It is
815 actually one of the more complex classes in the LLVM heirarchy because it must
816 keep track of a large amount of data. The <tt>Function</tt> class keeps track
817 of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
818 href="#Argument"><tt>Argument</tt></a>s, and a <a
819 href="#SymbolTable"><tt>SymbolTable</tt></a>.<p>
821 The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most commonly
822 used part of <tt>Function</tt> objects. The list imposes an implicit ordering
823 of the blocks in the function, which indicate how the code will be layed out by
824 the backend. Additionally, the first <a
825 href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
826 <tt>Function</tt>. It is not legal in LLVM explicitly branch to this initial
827 block. There are no implicit exit nodes, and in fact there may be multiple exit
828 nodes from a single <tt>Function</tt>. If the <a
829 href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
830 the <tt>Function</tt> is actually a function declaration: the actual body of the
831 function hasn't been linked in yet.<p>
833 In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
834 <tt>Function</tt> class also keeps track of the list of formal <a
835 href="#Argument"><tt>Argument</tt></a>s that the function receives. This
836 container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
837 nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
838 the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.<p>
840 The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used LLVM
841 feature that is only used when you have to look up a value by name. Aside from
842 that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used internally to
843 make sure that there are not conflicts between the names of <a
844 href="#Instruction"><tt>Instruction</tt></a>s, <a
845 href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
846 href="#Argument"><tt>Argument</tt></a>s in the function body.<p>
849 <!-- _______________________________________________________________________ -->
850 </ul><h4><a name="m_Function"><hr size=0>Important Public Members of
851 the <tt>Function</tt> class</h4><ul>
853 <li><tt>Function(const <a href="#FunctionType">FunctionType</a> *Ty, bool isInternal, const std::string &N = "")</tt><p>
855 Constructor used when you need to create new <tt>Function</tt>s to add the the
856 program. The constructor must specify the type of the function to create and
857 whether or not it should start out with internal or external linkage.<p>
859 <li><tt>bool isExternal()</tt><p>
861 Return whether or not the <tt>Function</tt> has a body defined. If the function
862 is "external", it does not have a body, and thus must be resolved by linking
863 with a function defined in a different translation unit.<p>
866 <li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
867 <tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
868 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
869 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
871 These are forwarding methods that make it easy to access the contents of a
872 <tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
875 <li><tt>Function::BasicBlockListType &getBasicBlockList()</tt><p>
877 Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This is
878 neccesary to use when you need to update the list or perform a complex action
879 that doesn't have a forwarding method.<p>
882 <li><tt>Function::aiterator</tt> - Typedef for the argument list iterator<br>
883 <tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
884 <tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
885 <tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt><p>
887 These are forwarding methods that make it easy to access the contents of a
888 <tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a> list.<p>
890 <li><tt>Function::ArgumentListType &getArgumentList()</tt><p>
892 Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This is
893 neccesary to use when you need to update the list or perform a complex action
894 that doesn't have a forwarding method.<p>
898 <li><tt><a href="#BasicBlock">BasicBlock</a> &getEntryNode()</tt><p>
900 Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
901 function. Because the entry block for the function is always the first block,
902 this returns the first block of the <tt>Function</tt>.<p>
904 <li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
905 <tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt><p>
907 This traverses the <a href="#Type"><tt>Type</tt></a> of the <tt>Function</tt>
908 and returns the return type of the function, or the <a
909 href="#FunctionType"><tt>FunctionType</tt></a> of the actual function.<p>
912 <li><tt>bool hasSymbolTable() const</tt><p>
914 Return true if the <tt>Function</tt> has a symbol table allocated to it and if
915 there is at least one entry in it.<p>
917 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
919 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
920 <tt>Function</tt> or a null pointer if one has not been allocated (because there
921 are no named values in the function).<p>
923 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
925 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
926 <tt>Function</tt> or allocate a new <a
927 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
928 should only be used when adding elements to the <a
929 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
930 not left laying around.<p>
934 <!-- ======================================================================= -->
935 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
936 <tr><td> </td><td width="100%">
937 <font color="#EEEEFF" face="Georgia,Palatino"><b>
938 <a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
939 </b></font></td></tr></table><ul>
942 href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt></b><br>
943 doxygen info: <a href="/doxygen/classGlobalVariable.html">GlobalVariable Class</a><br>
944 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
945 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
947 Global variables are represented with the (suprise suprise)
948 <tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are
949 also subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such
950 are always referenced by their address (global values must live in memory, so
951 their "name" refers to their address). Global variables may have an initial
952 value (which must be a <a href="#Constant"><tt>Constant</tt></a>), and if they
953 have an initializer, they may be marked as "constant" themselves (indicating
954 that their contents never change at runtime).<p>
957 <!-- _______________________________________________________________________ -->
958 </ul><h4><a name="m_GlobalVariable"><hr size=0>Important Public Members of the
959 <tt>GlobalVariable</tt> class</h4><ul>
961 <li><tt>GlobalVariable(const <a href="#Type">Type</a> *Ty, bool isConstant, bool
962 isInternal, <a href="#Constant">Constant</a> *Initializer = 0, const std::string
963 &Name = "")</tt><p>
965 Create a new global variable of the specified type. If <tt>isConstant</tt> is
966 true then the global variable will be marked as unchanging for the program, and
967 if <tt>isInternal</tt> is true the resultant global variable will have internal
968 linkage. Optionally an initializer and name may be specified for the global variable as well.<p>
971 <li><tt>bool isConstant() const</tt><p>
973 Returns true if this is a global variable is known not to be modified at
977 <li><tt>bool hasInitializer()</tt><p>
979 Returns true if this <tt>GlobalVariable</tt> has an intializer.<p>
982 <li><tt><a href="#Constant">Constant</a> *getInitializer()</tt><p>
984 Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal to call
985 this method if there is no initializer.<p>
988 <!-- ======================================================================= -->
989 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
990 <tr><td> </td><td width="100%">
991 <font color="#EEEEFF" face="Georgia,Palatino"><b>
992 <a name="Module">The <tt>Module</tt> class</a>
993 </b></font></td></tr></table><ul>
996 href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt></b><br>
997 doxygen info: <a href="/doxygen/classModule.html">Module Class</a><p>
999 The <tt>Module</tt> class represents the top level structure present in LLVM
1000 programs. An LLVM module is effectively either a translation unit of the
1001 original program or a combination of several translation units merged by the
1002 linker. The <tt>Module</tt> class keeps track of a list of <a
1003 href="#Function"><tt>Function</tt></a>s, a list of <a
1004 href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
1005 href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
1006 helpful member functions that try to make common operations easy.<p>
1009 <!-- _______________________________________________________________________ -->
1010 </ul><h4><a name="m_Module"><hr size=0>Important Public Members of the
1011 <tt>Module</tt> class</h4><ul>
1013 <li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
1014 <tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
1015 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
1016 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
1018 These are forwarding methods that make it easy to access the contents of a
1019 <tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
1022 <li><tt>Module::FunctionListType &getFunctionList()</tt><p>
1024 Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
1025 neccesary to use when you need to update the list or perform a complex action
1026 that doesn't have a forwarding method.<p>
1028 <!-- Global Variable -->
1031 <li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
1032 <tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
1033 <tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
1034 <tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt><p>
1036 These are forwarding methods that make it easy to access the contents of a
1037 <tt>Module</tt> object's <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>
1040 <li><tt>Module::GlobalListType &getGlobalList()</tt><p>
1042 Returns the list of <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s.
1043 This is neccesary to use when you need to update the list or perform a complex
1044 action that doesn't have a forwarding method.<p>
1047 <!-- Symbol table stuff -->
1050 <li><tt>bool hasSymbolTable() const</tt><p>
1052 Return true if the <tt>Module</tt> has a symbol table allocated to it and if
1053 there is at least one entry in it.<p>
1055 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
1057 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1058 <tt>Module</tt> or a null pointer if one has not been allocated (because there
1059 are no named values in the function).<p>
1061 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
1063 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1064 <tt>Module</tt> or allocate a new <a
1065 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
1066 should only be used when adding elements to the <a
1067 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
1068 not left laying around.<p>
1071 <!-- Convenience methods -->
1074 <li><tt><a href="#Function">Function</a> *getFunction(const std::string &Name, const <a href="#FunctionType">FunctionType</a> *Ty)</tt><p>
1076 Look up the specified function in the <tt>Module</tt> <a
1077 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
1081 <li><tt><a href="#Function">Function</a> *getOrInsertFunction(const std::string
1082 &Name, const <a href="#FunctionType">FunctionType</a> *T)</tt><p>
1084 Look up the specified function in the <tt>Module</tt> <a
1085 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, add an
1086 external declaration for the function and return it.<p>
1089 <li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt><p>
1091 If there is at least one entry in the <a
1092 href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
1093 href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
1097 <li><tt>bool addTypeName(const std::string &Name, const <a href="#Type">Type</a>
1100 Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a> mapping
1101 <tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this name, true
1102 is returned and the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is not
1106 <!-- ======================================================================= -->
1107 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1108 <tr><td> </td><td width="100%">
1109 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1110 <a name="Constant">The <tt>Constant</tt> class and subclasses</a>
1111 </b></font></td></tr></table><ul>
1113 Constant represents a base class for different types of constants. It is
1114 subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
1115 ConstantArray etc for representing the various types of Constants.<p>
1118 <!-- _______________________________________________________________________ -->
1119 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1121 <li><tt>bool isConstantExpr()</tt>: Returns true if it is a ConstantExpr
1126 \subsection{Important Subclasses of Constant}
1128 <li>ConstantSInt : This subclass of Constant represents a signed integer constant.
1130 <li><tt>int64_t getValue () const</tt>: Returns the underlying value of this constant.
1132 <li>ConstantUInt : This class represents an unsigned integer.
1134 <li><tt>uint64_t getValue () const</tt>: Returns the underlying value of this constant.
1136 <li>ConstantFP : This class represents a floating point constant.
1138 <li><tt>double getValue () const</tt>: Returns the underlying value of this constant.
1140 <li>ConstantBool : This represents a boolean constant.
1142 <li><tt>bool getValue () const</tt>: Returns the underlying value of this constant.
1144 <li>ConstantArray : This represents a constant array.
1146 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1148 <li>ConstantStruct : This represents a constant struct.
1150 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1152 <li>ConstantPointerRef : This represents a constant pointer value that is initialized to point to a global value, which lies at a constant fixed address.
1154 <li><tt>GlobalValue *getValue()</tt>: Returns the global value to which this pointer is pointing to.
1159 <!-- ======================================================================= -->
1160 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1161 <tr><td> </td><td width="100%">
1162 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1163 <a name="Type">The <tt>Type</tt> class and Derived Types</a>
1164 </b></font></td></tr></table><ul>
1166 Type as noted earlier is also a subclass of a Value class. Any primitive
1167 type (like int, short etc) in LLVM is an instance of Type Class. All
1168 other types are instances of subclasses of type like FunctionType,
1169 ArrayType etc. DerivedType is the interface for all such dervied types
1170 including FunctionType, ArrayType, PointerType, StructType. Types can have
1171 names. They can be recursive (StructType). There exists exactly one instance
1172 of any type structure at a time. This allows using pointer equality of Type *s for comparing types.
1174 <!-- _______________________________________________________________________ -->
1175 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1177 <li><tt>PrimitiveID getPrimitiveID () const</tt>: Returns the base type of the type.
1178 <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.
1179 <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.
1180 <li><tt> bool isInteger () const</tt>: Equilivent to isSigned() || isUnsigned(), but with only a single virtual function invocation.
1181 <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.
1183 <li><tt>bool isFloatingPoint ()</tt>: Return true if this is one of the two floating point types.
1184 <li><tt>bool isRecursive () const</tt>: Returns rue if the type graph contains a cycle.
1185 <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.
1186 <li><tt>bool isPrimitiveType () const</tt>: Returns true if it is a primitive type.
1187 <li><tt>bool isDerivedType () const</tt>: Returns true if it is a derived type.
1188 <li><tt>const Type * getContainedType (unsigned i) const</tt>:
1189 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.
1190 <li><tt>unsigned getNumContainedTypes () const</tt>: Return the number of types in the derived type.
1194 \subsection{Derived Types}
1196 <li>SequentialType : This is subclassed by ArrayType and PointerType
1198 <li><tt>const Type * getElementType () const</tt>: Returns the type of each of the elements in the sequential type.
1200 <li>ArrayType : This is a subclass of SequentialType and defines interface for array types.
1202 <li><tt>unsigned getNumElements () const</tt>: Returns the number of elements in the array.
1204 <li>PointerType : Subclass of SequentialType for pointer types.
1205 <li>StructType : subclass of DerivedTypes for struct types
1206 <li>FunctionType : subclass of DerivedTypes for function types.
1209 <li><tt>bool isVarArg () const</tt>: Returns true if its a vararg function
1210 <li><tt> const Type * getReturnType () const</tt>: Returns the return type of the function.
1211 <li><tt> const ParamTypes &getParamTypes () const</tt>: Returns a vector of parameter types.
1212 <li><tt>const Type * getParamType (unsigned i)</tt>: Returns the type of the ith parameter.
1213 <li><tt> const unsigned getNumParams () const</tt>: Returns the number of formal parameters.
1220 <!-- ======================================================================= -->
1221 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1222 <tr><td> </td><td width="100%">
1223 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1224 <a name="Argument">The <tt>Argument</tt> class</a>
1225 </b></font></td></tr></table><ul>
1227 This subclass of Value defines the interface for incoming formal arguments to a
1228 function. A Function maitanis a list of its formal arguments. An argument has a
1229 pointer to the parent Function.
1234 <!-- *********************************************************************** -->
1236 <!-- *********************************************************************** -->
1239 <address>By: <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
1240 <a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
1241 <!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
1242 <!-- hhmts start -->
1243 Last modified: Fri Sep 6 17:12:14 CDT 2002
1245 </font></body></html>