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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 example</a>
29 <li><a href="#simplechanges">Making simple changes</a>
31 <li>Creating and inserting new <tt>Instruction</tt>s
32 <li>Deleting <tt>Instruction</tt>s
33 <li>Replacing an <tt>Instruction</tt> with another <tt>Value</tt>
36 <li>Working with the Control Flow Graph
38 <li>Accessing predecessors and successors of a <tt>BasicBlock</tt>
45 <li>isa<>, cast<>, and dyn_cast<> templates
47 <li>The general graph API
48 <li>The <tt>InstVisitor</tt> template
50 <li>The <tt>Statistic</tt> template
54 <li>Useful related topics
56 <li>The <tt>-time-passes</tt> option
57 <li>How to use the LLVM Makefile system
58 <li>How to write a regression test
63 <li><a href="#coreclasses">The Core LLVM Class Hierarchy Reference</a>
65 <li><a href="#Value">The <tt>Value</tt> class</a>
67 <li><a href="#User">The <tt>User</tt> class</a>
69 <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 and <a href="mailto:sabre@nondot.org">Chris Lattner</a></b><p>
103 <!-- *********************************************************************** -->
104 <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
105 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
106 <a name="introduction">Introduction
107 </b></font></td></tr></table><ul>
108 <!-- *********************************************************************** -->
110 This document is meant to highlight some of the important classes and interfaces
111 available in the LLVM source-base. This manual is not intended to explain what
112 LLVM is, how it works, and what LLVM code looks like. It assumes that you know
113 the basics of LLVM and are interested in writing transformations or otherwise
114 analyzing or manipulating the code.<p>
116 This document should get you oriented so that you can find your way in the
117 continuously growing source code that makes up the LLVM infrastructure. Note
118 that this manual is not intended to serve as a replacement for reading the
119 source code, so if you think there should be a method in one of these classes to
120 do something, but it's not listed, check the source. Links to the <a
121 href="/doxygen/">doxygen</a> sources are provided to make this as easy as
124 The first section of this document describes general information that is useful
125 to know when working in the LLVM infrastructure, and the second describes the
126 Core LLVM classes. In the future this manual will be extended with information
127 describing how to use extension libraries, such as dominator information, CFG
128 traversal routines, and useful utilities like the <tt><a
129 href="/doxygen/InstVisitor_8h-source.html">InstVisitor</a></tt> template.<p>
132 <!-- *********************************************************************** -->
133 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
134 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
135 <a name="general">General Information
136 </b></font></td></tr></table><ul>
137 <!-- *********************************************************************** -->
139 This section contains general information that is useful if you are working in
140 the LLVM source-base, but that isn't specific to any particular API.<p>
143 <!-- ======================================================================= -->
144 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
145 <tr><td> </td><td width="100%">
146 <font color="#EEEEFF" face="Georgia,Palatino"><b>
147 <a name="stl">The C++ Standard Template Library</a>
148 </b></font></td></tr></table><ul>
150 LLVM makes heavy use of the C++ Standard Template Library (STL), perhaps much
151 more than you are used to, or have seen before. Because of this, you might want
152 to do a little background reading in the techniques used and capabilities of the
153 library. There are many good pages that discuss the STL, and several books on
154 the subject that you can get, so it will not be discussed in this document.<p>
156 Here are some useful links:<p>
158 <li><a href="http://www.dinkumware.com/htm_cpl/index.html">Dinkumware C++
159 Library reference</a> - an excellent reference for the STL and other parts of
160 the standard C++ library.<br>
162 <li><a href="http://www.parashift.com/c++-faq-lite/">C++ Frequently Asked
165 <li><a href="http://www.sgi.com/tech/stl/">SGI's STL Programmer's Guide</a> -
167 href="http://www.sgi.com/tech/stl/stl_introduction.html">Introduction to the
170 <li><a href="http://www.research.att.com/~bs/C++.html">Bjarne Stroustrup's C++
175 You are also encouraged to take a look at the <a
176 href="CodingStandards.html">LLVM Coding Standards</a> guide which focuses on how
177 to write maintainable code more than where to put your curly braces.<p>
181 <!-- *********************************************************************** -->
182 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
183 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
184 <a name="common">Helpful Hints for Common Operations
185 </b></font></td></tr></table><ul>
186 <!-- *********************************************************************** -->
188 This section describes how to perform some very simple transformations of LLVM
189 code. This is meant to give examples of common idioms used, showing the
190 practical side of LLVM transformations.<p>
192 Because this is a "how-to" section, you should also read about the main classes
193 that you will be working with. The <a href="#coreclasses">Core LLVM Class
194 Hierarchy Reference</a> contains details and descriptions of the main classes
195 that you should know about.<p>
197 <!-- NOTE: this section should be heavy on example code -->
200 <!-- ======================================================================= -->
201 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
202 <tr><td> </td><td width="100%">
203 <font color="#EEEEFF" face="Georgia,Palatino"><b>
204 <a name="inspection">Basic Inspection and Traversal Routines</a>
205 </b></font></td></tr></table><ul>
208 <!-- LLVM has heirarchical representation: Module, Function, BasicBlock,
209 Instruction. Common patterns for all levels. -->
211 <!-- _______________________________________________________________________ -->
212 </ul><h4><a name="iterate_function"><hr size=0>Iterating over the
213 <tt>BasicBlock</tt>s in a <tt>Function</tt> </h4><ul>
215 It's quite common to have a <tt>Function</tt> instance that you'd like
216 to transform in some way; in particular, you'd like to manipulate its
217 <tt>BasicBlock</tt>s. To facilitate this, you'll need to iterate over
218 all of the <tt>BasicBlock</tt>s that constitute the <tt>Function</tt>.
219 The following is an example that prints the name of a
220 <tt>BasicBlock</tt> and the number of <tt>Instruction</tt>s it
224 // func is a pointer to a Function instance
225 for(Function::iterator i = func->begin(), e = func->end(); i != e; ++i) {
227 // print out the name of the basic block if it has one, and then the
228 // number of instructions that it contains
230 cerr << "Basic block (name=" << i->getName() << ") has "
231 << i->size() << " instructions.\n";
235 Note that i can be used as if it were a pointer for the purposes of
236 invoking member functions of the <tt>Instruction</tt> class. This is
237 because the indirection operator is overloaded for the iterator
238 classes. In the above code, the expression <tt>i->size()</tt> is
239 exactly equivalent to <tt>(*i).size()</tt> just like you'd expect.
241 <!-- _______________________________________________________________________ -->
242 </ul><h4><a name="iterate_basicblock"><hr size=0>Iterating over the
243 <tt>Instruction</tt>s in a <tt>BasicBlock</tt> </h4><ul>
245 Just like when dealing with <tt>BasicBlock</tt>s in <tt>Function</tt>s, it's
246 easy to iterate over the individual instructions that make up
247 <tt>BasicBlock</tt>s. Here's a code snippet that prints out each instruction in
248 a <tt>BasicBlock</tt>:
251 // blk is a pointer to a BasicBlock instance
252 for(BasicBlock::iterator i = blk->begin(), e = blk->end(); i != e; ++i) {
253 // the next statement works since operator<<(ostream&,...)
254 // is overloaded for Instruction&
260 However, this isn't really the best way to print out the contents of a
261 <tt>BasicBlock</tt>! Since the ostream operators are overloaded for
262 virtually anything you'll care about, you could have just invoked the
263 print routine on the basic block itself: <tt>cerr << blk <<
264 endl;</tt>. You might expect this to print out the pointer value of
265 blk, but operator<< is overloaded for BasicBlock* as well: if you
266 really want to print the pointer value explicitly, you'll have to
269 <!-- _______________________________________________________________________ -->
270 </ul><h4><a name="iterate_convert"><hr size=0>Turning an iterator into a class
273 Sometimes, it'll be useful to grab a reference (or pointer) to a class
274 instance when all you've got at hand is an iterator. Well, extracting
275 a reference or a pointer from an iterator is very straightforward.
276 Assuming that <tt>i</tt> is a <tt>BasicBlock::iterator</tt> and
277 <tt>j</tt> is a <tt>BasicBlock::const_iterator</tt>:
280 Instruction& inst = *i; // grab reference to instruction reference
281 Instruction* pinst = &*i; // grab pointer to instruction reference
282 const Instruction& inst = *j;
284 However, the iterators you'll be working with in the LLVM framework
285 are special: they will automatically convert to a ptr-to-instance type
286 whenever they need to. Instead of dereferencing the iterator and then
287 taking the address of the result, you can simply assign the iterator
288 to the proper pointer type and you get the dereference and address-of
289 operation as a result of the assignment (behind the scenes, this is a
290 result of overloading casting mechanisms). Thus the last line of the
293 <pre>Instruction* pinst = &*i;</pre>
295 is semantically equivalent to
297 <pre>Instruction* pinst = i;</pre>
299 <b>Caveat emptor</b>: The above syntax works <i>only</i> when you're
300 <i>not</i> working with <tt>dyn_cast</tt>. The template definition of
301 <tt>dyn_cast</tt> isn't implemented to handle this yet, so you'll
302 still need the following in order for things to work properly:
305 BasicBlock::iterator bbi = ...;
306 BranchInst* b = dyn_cast<BranchInst>(&*bbi);
309 The following code snippet illustrates use of the conversion
310 constructors provided by LLVM iterators. By using these, you can
311 explicitly grab the iterator of something without actually obtaining
312 it via iteration over some structure:
315 void printNextInstruction(Instruction* inst) {
316 BasicBlock::iterator it(inst);
317 ++it; // after this line, it refers to the instruction after *inst.
318 if(it != inst->getParent()->end()) cerr << *it << endl;
322 Of course, this example is strictly pedagogical, because it'd be
323 better to do something like
325 <pre>if(inst->getNext()) cerr << inst->getNext() << endl;</pre>
328 <!-- dereferenced iterator = Class &
329 iterators have converting constructor for 'Class *'
330 iterators automatically convert to 'Class *' except in dyn_cast<> case
334 _______________________________________________________________________
335 --> </ul><h4><a name="iterate_complex"><hr size=0>Finding call sites:
336 a slightly more complex example
339 Say that you're writing a FunctionPass and would like to count all the
340 locations in the entire module (that is, across every <tt>Function</tt>)
341 where a certain function named foo (that takes an int and returns an
342 int) is called. As you'll learn later, you may want to use an
343 <tt>InstVisitor</tt> to accomplish this in a much more straightforward
344 manner, but this example will allow us to explore how you'd do it if
345 you didn't have <tt>InstVisitor</tt> around. In pseudocode, this is
349 initialize callCounter to zero
350 for each Function f in the Module
351 for each BasicBlock b in f
352 for each Instruction i in b
353 if(i is a CallInst and foo is the function it calls)
354 increment callCounter
357 And the actual code is (remember, since we're writing a
358 <tt>FunctionPass</tt> our <tt>FunctionPass</tt>-derived class simply
359 has to override the <tt>runOnFunction</tt> method...):
363 // Assume callCounter is a private member of the pass class being written,
364 // and has been initialized in the pass class constructor.
366 virtual runOnFunction(Function& F) {
368 // Remember, we assumed that the signature of foo was "int foo(int)";
369 // the first thing we'll do is grab the pointer to that function (as a
370 // Function*) so we can use it later when we're examining the
371 // parameters of a CallInst. All of the code before the call to
372 // Module::getOrInsertFunction() is in preparation to do symbol-table
373 // to find the function pointer.
375 vector<const Type*> params;
376 params.push_back(Type::IntTy);
377 const FunctionType* fooType = FunctionType::get(Type::IntTy, params);
378 Function* foo = F.getParent()->getOrInsertFunction("foo", fooType);
380 // Start iterating and (as per the pseudocode), increment callCounter.
382 for(Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
383 for(BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {
384 if(CallInst* callInst = dyn_cast<CallInst>(&*inst)) {
385 // we know we've encountered a call instruction, so we
386 // need to determine if it's a call to foo or not
388 if(callInst->getCalledFunction() == foo)
396 We could then print out the value of callCounter (if we wanted to)
397 inside the doFinalization method of our FunctionPass.
400 <!-- ======================================================================= -->
401 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
402 <tr><td> </td><td width="100%">
403 <font color="#EEEEFF" face="Georgia,Palatino"><b>
404 <a name="simplechanges">Making simple changes</a>
405 </b></font></td></tr></table><ul>
407 <!-- Value::replaceAllUsesWith
408 User::replaceUsesOfWith
409 Point out: include/llvm/Transforms/Utils/
410 especially BasicBlockUtils.h with:
411 ReplaceInstWithValue, ReplaceInstWithInst
416 <!-- *********************************************************************** -->
417 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
418 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
419 <a name="coreclasses">The Core LLVM Class Hierarchy Reference
420 </b></font></td></tr></table><ul>
421 <!-- *********************************************************************** -->
423 The Core LLVM classes are the primary means of representing the program being
424 inspected or transformed. The core LLVM classes are defined in header files in
425 the <tt>include/llvm/</tt> directory, and implemented in the <tt>lib/VMCore</tt>
429 <!-- ======================================================================= -->
430 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
431 <tr><td> </td><td width="100%">
432 <font color="#EEEEFF" face="Georgia,Palatino"><b>
433 <a name="Value">The <tt>Value</tt> class</a>
434 </b></font></td></tr></table><ul>
436 <tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt></b><br>
437 doxygen info: <a href="/doxygen/classValue.html">Value Class</a><p>
440 The <tt>Value</tt> class is the most important class in LLVM Source base. It
441 represents a typed value that may be used (among other things) as an operand to
442 an instruction. There are many different types of <tt>Value</tt>s, such as <a
443 href="#Constant"><tt>Constant</tt></a>s, <a
444 href="#Argument"><tt>Argument</tt></a>s, and even <a
445 href="#Instruction"><tt>Instruction</tt></a>s and <a
446 href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.<p>
448 A particular <tt>Value</tt> may be used many times in the LLVM representation
449 for a program. For example, an incoming argument to a function (represented
450 with an instance of the <a href="#Argument">Argument</a> class) is "used" by
451 every instruction in the function that references the argument. To keep track
452 of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
453 href="#User"><tt>User</tt></a>s that is using it (the <a
454 href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
455 graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
456 def-use information in the program, and is accessible through the <tt>use_</tt>*
457 methods, shown below.<p>
459 Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed, and
460 this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
461 method. <a name="#nameWarning">In addition, all LLVM values can be named. The
462 "name" of the <tt>Value</tt> is symbolic string printed in the LLVM code:<p>
465 %<b>foo</b> = add int 1, 2
468 The name of this instruction is "foo". <b>NOTE</b> that the name of any value
469 may be missing (an empty string), so names should <b>ONLY</b> be used for
470 debugging (making the source code easier to read, debugging printouts), they
471 should not be used to keep track of values or map between them. For this
472 purpose, use a <tt>std::map</tt> of pointers to the <tt>Value</tt> itself
475 One important aspect of LLVM is that there is no distinction between an SSA
476 variable and the operation that produces it. Because of this, any reference to
477 the value produced by an instruction (or the value available as an incoming
478 argument, for example) is represented as a direct pointer to the class that
479 represents this value. Although this may take some getting used to, it
480 simplifies the representation and makes it easier to manipulate.<p>
483 <!-- _______________________________________________________________________ -->
484 </ul><h4><a name="m_Value"><hr size=0>Important Public Members of
485 the <tt>Value</tt> class</h4><ul>
487 <li><tt>Value::use_iterator</tt> - Typedef for iterator over the use-list<br>
488 <tt>Value::use_const_iterator</tt>
489 - Typedef for const_iterator over the use-list<br>
490 <tt>unsigned use_size()</tt> - Returns the number of users of the value.<br>
491 <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
492 <tt>use_iterator use_begin()</tt>
493 - Get an iterator to the start of the use-list.<br>
494 <tt>use_iterator use_end()</tt>
495 - Get an iterator to the end of the use-list.<br>
496 <tt><a href="#User">User</a> *use_back()</tt>
497 - Returns the last element in the list.<p>
499 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>
501 <li><tt><a href="#Type">Type</a> *getType() const</tt><p>
502 This method returns the Type of the Value.
504 <li><tt>bool hasName() const</tt><br>
505 <tt>std::string getName() const</tt><br>
506 <tt>void setName(const std::string &Name)</tt><p>
508 This family of methods is used to access and assign a name to a <tt>Value</tt>,
509 be aware of the <a href="#nameWarning">precaution above</a>.<p>
512 <li><tt>void replaceAllUsesWith(Value *V)</tt><p>
514 This method traverses the use list of a <tt>Value</tt> changing all <a
515 href="#User"><tt>User</tt>'s</a> of the current value to refer to "<tt>V</tt>"
516 instead. For example, if you detect that an instruction always produces a
517 constant value (for example through constant folding), you can replace all uses
518 of the instruction with the constant like this:<p>
521 Inst->replaceAllUsesWith(ConstVal);
526 <!-- ======================================================================= -->
527 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
528 <tr><td> </td><td width="100%">
529 <font color="#EEEEFF" face="Georgia,Palatino"><b>
530 <a name="User">The <tt>User</tt> class</a>
531 </b></font></td></tr></table><ul>
533 <tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt></b><br>
534 doxygen info: <a href="/doxygen/classUser.html">User Class</a><br>
535 Superclass: <a href="#Value"><tt>Value</tt></a><p>
538 The <tt>User</tt> class is the common base class of all LLVM nodes that may
539 refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
540 that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
541 referring to. The <tt>User</tt> class itself is a subclass of
544 The operands of a <tt>User</tt> point directly to the LLVM <a
545 href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
546 Single Assignment (SSA) form, there can only be one definition referred to,
547 allowing this direct connection. This connection provides the use-def
548 information in LLVM.<p>
550 <!-- _______________________________________________________________________ -->
551 </ul><h4><a name="m_User"><hr size=0>Important Public Members of
552 the <tt>User</tt> class</h4><ul>
554 The <tt>User</tt> class exposes the operand list in two ways: through an index
555 access interface and through an iterator based interface.<p>
557 <li><tt>Value *getOperand(unsigned i)</tt><br>
558 <tt>unsigned getNumOperands()</tt><p>
560 These two methods expose the operands of the <tt>User</tt> in a convenient form
561 for direct access.<p>
563 <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand list<br>
564 <tt>User::op_const_iterator</tt>
565 <tt>use_iterator op_begin()</tt>
566 - Get an iterator to the start of the operand list.<br>
567 <tt>use_iterator op_end()</tt>
568 - Get an iterator to the end of the operand list.<p>
570 Together, these methods make up the iterator based interface to the operands of
575 <!-- ======================================================================= -->
576 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
577 <tr><td> </td><td width="100%">
578 <font color="#EEEEFF" face="Georgia,Palatino"><b>
579 <a name="Instruction">The <tt>Instruction</tt> class</a>
580 </b></font></td></tr></table><ul>
583 href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt></b><br>
584 doxygen info: <a href="/doxygen/classInstruction.html">Instruction Class</a><br>
585 Superclasses: <a href="#User"><tt>User</tt></a>, <a
586 href="#Value"><tt>Value</tt></a><p>
588 The <tt>Instruction</tt> class is the common base class for all LLVM
589 instructions. It provides only a few methods, but is a very commonly used
590 class. The primary data tracked by the <tt>Instruction</tt> class itself is the
591 opcode (instruction type) and the parent <a
592 href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
593 into. To represent a specific type of instruction, one of many subclasses of
594 <tt>Instruction</tt> are used.<p>
596 Because the <tt>Instruction</tt> class subclasses the <a
597 href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
598 way as for other <a href="#User"><tt>User</tt></a>s (with the
599 <tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
600 <tt>op_begin()</tt>/<tt>op_end()</tt> methods).<p>
603 <!-- _______________________________________________________________________ -->
604 </ul><h4><a name="m_Instruction"><hr size=0>Important Public Members of
605 the <tt>Instruction</tt> class</h4><ul>
607 <li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt><p>
609 Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that this
610 <tt>Instruction</tt> is embedded into.<p>
612 <li><tt>bool hasSideEffects()</tt><p>
614 Returns true if the instruction has side effects, i.e. it is a <tt>call</tt>,
615 <tt>free</tt>, <tt>invoke</tt>, or <tt>store</tt>.<p>
617 <li><tt>unsigned getOpcode()</tt><p>
619 Returns the opcode for the <tt>Instruction</tt>.<p>
623 \subsection{Subclasses of Instruction :}
625 <li>BinaryOperator : This subclass of Instruction defines a general interface to the all the instructions involvong binary operators in LLVM.
627 <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.
629 <li>TerminatorInst : This subclass of Instructions defines an interface for all instructions that can terminate a BasicBlock.
631 <li> <tt>unsigned getNumSuccessors()</tt>: Returns the number of successors for this terminator instruction.
632 <li><tt>BasicBlock *getSuccessor(unsigned i)</tt>: As the name suggests returns the ith successor BasicBlock.
633 <li><tt>void setSuccessor(unsigned i, BasicBlock *B)</tt>: sets BasicBlock B as the ith succesor to this terminator instruction.
636 <li>PHINode : This represents the PHI instructions in the SSA form.
638 <li><tt> unsigned getNumIncomingValues()</tt>: Returns the number of incoming edges to this PHI node.
639 <li><tt> Value *getIncomingValue(unsigned i)</tt>: Returns the ith incoming Value.
640 <li><tt>void setIncomingValue(unsigned i, Value *V)</tt>: Sets the ith incoming Value as V
641 <li><tt>BasicBlock *getIncomingBlock(unsigned i)</tt>: Returns the Basic Block corresponding to the ith incoming Value.
642 <li><tt> void addIncoming(Value *D, BasicBlock *BB)</tt>:
643 Add an incoming value to the end of the PHI list
644 <li><tt> int getBasicBlockIndex(const BasicBlock *BB) const</tt>:
645 Returns the first index of the specified basic block in the value list for this PHI. Returns -1 if no instance.
647 <li>CastInst : In LLVM all casts have to be done through explicit cast instructions. CastInst defines the interface to the cast instructions.
648 <li>CallInst : This defines an interface to the call instruction in LLVM. ARguments to the function are nothing but operands of the instruction.
650 <li>: <tt>Function *getCalledFunction()</tt>: Returns a handle to the function that is being called by this Function.
652 <li>LoadInst, StoreInst, GetElemPtrInst : These subclasses represent load, store and getelementptr instructions in LLVM.
654 <li><tt>Value * getPointerOperand ()</tt>: Returns the Pointer Operand which is typically the 0th operand.
656 <li>BranchInst : This is a subclass of TerminatorInst and defines the interface for conditional and unconditional branches in LLVM.
658 <li><tt>bool isConditional()</tt>: Returns true if the branch is a conditional branch else returns false
659 <li> <tt>Value *getCondition()</tt>: Returns the condition if it is a conditional branch else returns null.
660 <li> <tt>void setUnconditionalDest(BasicBlock *Dest)</tt>: Changes the current branch to an unconditional one targetting the specified block.
668 <!-- ======================================================================= -->
669 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
670 <tr><td> </td><td width="100%">
671 <font color="#EEEEFF" face="Georgia,Palatino"><b>
672 <a name="BasicBlock">The <tt>BasicBlock</tt> class</a>
673 </b></font></td></tr></table><ul>
676 href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt></b><br>
677 doxygen info: <a href="/doxygen/classBasicBlock.html">BasicBlock Class</a><br>
678 Superclass: <a href="#Value"><tt>Value</tt></a><p>
681 This class represents a single entry multiple exit section of the code, commonly
682 known as a basic block by the compiler community. The <tt>BasicBlock</tt> class
683 maintains a list of <a href="#Instruction"><tt>Instruction</tt></a>s, which form
684 the body of the block. Matching the language definition, the last element of
685 this list of instructions is always a terminator instruction (a subclass of the
686 <a href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).<p>
688 In addition to tracking the list of instructions that make up the block, the
689 <tt>BasicBlock</tt> class also keeps track of the <a
690 href="#Function"><tt>Function</tt></a> that it is embedded into.<p>
692 Note that <tt>BasicBlock</tt>s themselves are <a
693 href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
694 like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
698 <!-- _______________________________________________________________________ -->
699 </ul><h4><a name="m_BasicBlock"><hr size=0>Important Public Members of
700 the <tt>BasicBlock</tt> class</h4><ul>
702 <li><tt>BasicBlock(const std::string &Name = "", <a
703 href="#Function">Function</a> *Parent = 0)</tt><p>
705 The <tt>BasicBlock</tt> constructor is used to create new basic blocks for
706 insertion into a function. The constructor simply takes a name for the new
707 block, and optionally a <a href="#Function"><tt>Function</tt></a> to insert it
708 into. If the <tt>Parent</tt> parameter is specified, the new
709 <tt>BasicBlock</tt> is automatically inserted at the end of the specified <a
710 href="#Function"><tt>Function</tt></a>, if not specified, the BasicBlock must be
711 manually inserted into the <a href="#Function"><tt>Function</tt></a>.<p>
713 <li><tt>BasicBlock::iterator</tt> - Typedef for instruction list iterator<br>
714 <tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
715 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
716 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
718 These methods and typedefs are forwarding functions that have the same semantics
719 as the standard library methods of the same names. These methods expose the
720 underlying instruction list of a basic block in a way that is easy to
721 manipulate. To get the full complement of container operations (including
722 operations to update the list), you must use the <tt>getInstList()</tt>
725 <li><tt>BasicBlock::InstListType &getInstList()</tt><p>
727 This method is used to get access to the underlying container that actually
728 holds the Instructions. This method must be used when there isn't a forwarding
729 function in the <tt>BasicBlock</tt> class for the operation that you would like
730 to perform. Because there are no forwarding functions for "updating"
731 operations, you need to use this if you want to update the contents of a
732 <tt>BasicBlock</tt>.<p>
734 <li><tt><A href="#Function">Function</a> *getParent()</tt><p>
736 Returns a pointer to <a href="#Function"><tt>Function</tt></a> the block is
737 embedded into, or a null pointer if it is homeless.<p>
739 <li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt><p>
741 Returns a pointer to the terminator instruction that appears at the end of the
742 <tt>BasicBlock</tt>. If there is no terminator instruction, or if the last
743 instruction in the block is not a terminator, then a null pointer is
747 <!-- ======================================================================= -->
748 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
749 <tr><td> </td><td width="100%">
750 <font color="#EEEEFF" face="Georgia,Palatino"><b>
751 <a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
752 </b></font></td></tr></table><ul>
755 href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt></b><br>
756 doxygen info: <a href="/doxygen/classGlobalValue.html">GlobalValue Class</a><br>
757 Superclasses: <a href="#User"><tt>User</tt></a>, <a
758 href="#Value"><tt>Value</tt></a><p>
760 Global values (<A href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
761 href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
762 visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
763 Because they are visible at global scope, they are also subject to linking with
764 other globals defined in different translation units. To control the linking
765 process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
766 <tt>GlobalValue</tt>s know whether they have internal or external linkage.<p>
768 If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
769 <tt>static</tt> in C), it is not visible to code outside the current translation
770 unit, and does not participate in linking. If it has external linkage, it is
771 visible to external code, and does participate in linking. In addition to
772 linkage information, <tt>GlobalValue</tt>s keep track of which <a
773 href="#Module"><tt>Module</tt></a> they are currently part of.<p>
775 Because <tt>GlobalValue</tt>s are memory objects, they are always referred to by
776 their address. As such, the <a href="#Type"><tt>Type</tt></a> of a global is
777 always a pointer to its contents. This is explained in the LLVM Language
781 <!-- _______________________________________________________________________ -->
782 </ul><h4><a name="m_GlobalValue"><hr size=0>Important Public Members of
783 the <tt>GlobalValue</tt> class</h4><ul>
785 <li><tt>bool hasInternalLinkage() const</tt><br>
786 <tt>bool hasExternalLinkage() const</tt><br>
787 <tt>void setInternalLinkage(bool HasInternalLinkage)</tt><p>
789 These methods manipulate the linkage characteristics of the
790 <tt>GlobalValue</tt>.<p>
792 <li><tt><a href="#Module">Module</a> *getParent()</tt><p>
794 This returns the <a href="#Module"><tt>Module</tt></a> that the GlobalValue is
795 currently embedded into.<p>
799 <!-- ======================================================================= -->
800 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
801 <tr><td> </td><td width="100%">
802 <font color="#EEEEFF" face="Georgia,Palatino"><b>
803 <a name="Function">The <tt>Function</tt> class</a>
804 </b></font></td></tr></table><ul>
807 href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt></b><br>
808 doxygen info: <a href="/doxygen/classFunction.html">Function Class</a><br>
809 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
810 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
812 The <tt>Function</tt> class represents a single procedure in LLVM. It is
813 actually one of the more complex classes in the LLVM heirarchy because it must
814 keep track of a large amount of data. The <tt>Function</tt> class keeps track
815 of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
816 href="#Argument"><tt>Argument</tt></a>s, and a <a
817 href="#SymbolTable"><tt>SymbolTable</tt></a>.<p>
819 The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most commonly
820 used part of <tt>Function</tt> objects. The list imposes an implicit ordering
821 of the blocks in the function, which indicate how the code will be layed out by
822 the backend. Additionally, the first <a
823 href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
824 <tt>Function</tt>. It is not legal in LLVM explicitly branch to this initial
825 block. There are no implicit exit nodes, and in fact there may be multiple exit
826 nodes from a single <tt>Function</tt>. If the <a
827 href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
828 the <tt>Function</tt> is actually a function declaration: the actual body of the
829 function hasn't been linked in yet.<p>
831 In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
832 <tt>Function</tt> class also keeps track of the list of formal <a
833 href="#Argument"><tt>Argument</tt></a>s that the function receives. This
834 container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
835 nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
836 the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.<p>
838 The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used LLVM
839 feature that is only used when you have to look up a value by name. Aside from
840 that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used internally to
841 make sure that there are not conflicts between the names of <a
842 href="#Instruction"><tt>Instruction</tt></a>s, <a
843 href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
844 href="#Argument"><tt>Argument</tt></a>s in the function body.<p>
847 <!-- _______________________________________________________________________ -->
848 </ul><h4><a name="m_Function"><hr size=0>Important Public Members of
849 the <tt>Function</tt> class</h4><ul>
851 <li><tt>Function(const <a href="#FunctionType">FunctionType</a> *Ty, bool isInternal, const std::string &N = "")</tt><p>
853 Constructor used when you need to create new <tt>Function</tt>s to add the the
854 program. The constructor must specify the type of the function to create and
855 whether or not it should start out with internal or external linkage.<p>
857 <li><tt>bool isExternal()</tt><p>
859 Return whether or not the <tt>Function</tt> has a body defined. If the function
860 is "external", it does not have a body, and thus must be resolved by linking
861 with a function defined in a different translation unit.<p>
864 <li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
865 <tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
866 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
867 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
869 These are forwarding methods that make it easy to access the contents of a
870 <tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
873 <li><tt>Function::BasicBlockListType &getBasicBlockList()</tt><p>
875 Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This is
876 neccesary to use when you need to update the list or perform a complex action
877 that doesn't have a forwarding method.<p>
880 <li><tt>Function::aiterator</tt> - Typedef for the argument list iterator<br>
881 <tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
882 <tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
883 <tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt><p>
885 These are forwarding methods that make it easy to access the contents of a
886 <tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a> list.<p>
888 <li><tt>Function::ArgumentListType &getArgumentList()</tt><p>
890 Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This is
891 neccesary to use when you need to update the list or perform a complex action
892 that doesn't have a forwarding method.<p>
896 <li><tt><a href="#BasicBlock">BasicBlock</a> &getEntryNode()</tt><p>
898 Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
899 function. Because the entry block for the function is always the first block,
900 this returns the first block of the <tt>Function</tt>.<p>
902 <li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
903 <tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt><p>
905 This traverses the <a href="#Type"><tt>Type</tt></a> of the <tt>Function</tt>
906 and returns the return type of the function, or the <a
907 href="#FunctionType"><tt>FunctionType</tt></a> of the actual function.<p>
910 <li><tt>bool hasSymbolTable() const</tt><p>
912 Return true if the <tt>Function</tt> has a symbol table allocated to it and if
913 there is at least one entry in it.<p>
915 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
917 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
918 <tt>Function</tt> or a null pointer if one has not been allocated (because there
919 are no named values in the function).<p>
921 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
923 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
924 <tt>Function</tt> or allocate a new <a
925 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
926 should only be used when adding elements to the <a
927 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
928 not left laying around.<p>
932 <!-- ======================================================================= -->
933 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
934 <tr><td> </td><td width="100%">
935 <font color="#EEEEFF" face="Georgia,Palatino"><b>
936 <a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
937 </b></font></td></tr></table><ul>
940 href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt></b><br>
941 doxygen info: <a href="/doxygen/classGlobalVariable.html">GlobalVariable Class</a><br>
942 Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
943 href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a><p>
945 Global variables are represented with the (suprise suprise)
946 <tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are
947 also subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such
948 are always referenced by their address (global values must live in memory, so
949 their "name" refers to their address). Global variables may have an initial
950 value (which must be a <a href="#Constant"><tt>Constant</tt></a>), and if they
951 have an initializer, they may be marked as "constant" themselves (indicating
952 that their contents never change at runtime).<p>
955 <!-- _______________________________________________________________________ -->
956 </ul><h4><a name="m_GlobalVariable"><hr size=0>Important Public Members of the
957 <tt>GlobalVariable</tt> class</h4><ul>
959 <li><tt>GlobalVariable(const <a href="#Type">Type</a> *Ty, bool isConstant, bool
960 isInternal, <a href="#Constant">Constant</a> *Initializer = 0, const std::string
961 &Name = "")</tt><p>
963 Create a new global variable of the specified type. If <tt>isConstant</tt> is
964 true then the global variable will be marked as unchanging for the program, and
965 if <tt>isInternal</tt> is true the resultant global variable will have internal
966 linkage. Optionally an initializer and name may be specified for the global variable as well.<p>
969 <li><tt>bool isConstant() const</tt><p>
971 Returns true if this is a global variable is known not to be modified at
975 <li><tt>bool hasInitializer()</tt><p>
977 Returns true if this <tt>GlobalVariable</tt> has an intializer.<p>
980 <li><tt><a href="#Constant">Constant</a> *getInitializer()</tt><p>
982 Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal to call
983 this method if there is no initializer.<p>
986 <!-- ======================================================================= -->
987 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
988 <tr><td> </td><td width="100%">
989 <font color="#EEEEFF" face="Georgia,Palatino"><b>
990 <a name="Module">The <tt>Module</tt> class</a>
991 </b></font></td></tr></table><ul>
994 href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt></b><br>
995 doxygen info: <a href="/doxygen/classModule.html">Module Class</a><p>
997 The <tt>Module</tt> class represents the top level structure present in LLVM
998 programs. An LLVM module is effectively either a translation unit of the
999 original program or a combination of several translation units merged by the
1000 linker. The <tt>Module</tt> class keeps track of a list of <a
1001 href="#Function"><tt>Function</tt></a>s, a list of <a
1002 href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
1003 href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
1004 helpful member functions that try to make common operations easy.<p>
1007 <!-- _______________________________________________________________________ -->
1008 </ul><h4><a name="m_Module"><hr size=0>Important Public Members of the
1009 <tt>Module</tt> class</h4><ul>
1011 <li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
1012 <tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
1013 <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
1014 <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt><p>
1016 These are forwarding methods that make it easy to access the contents of a
1017 <tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
1020 <li><tt>Module::FunctionListType &getFunctionList()</tt><p>
1022 Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
1023 neccesary to use when you need to update the list or perform a complex action
1024 that doesn't have a forwarding method.<p>
1026 <!-- Global Variable -->
1029 <li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
1030 <tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
1031 <tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
1032 <tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt><p>
1034 These are forwarding methods that make it easy to access the contents of a
1035 <tt>Module</tt> object's <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>
1038 <li><tt>Module::GlobalListType &getGlobalList()</tt><p>
1040 Returns the list of <a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s.
1041 This is neccesary to use when you need to update the list or perform a complex
1042 action that doesn't have a forwarding method.<p>
1045 <!-- Symbol table stuff -->
1048 <li><tt>bool hasSymbolTable() const</tt><p>
1050 Return true if the <tt>Module</tt> has a symbol table allocated to it and if
1051 there is at least one entry in it.<p>
1053 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt><p>
1055 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1056 <tt>Module</tt> or a null pointer if one has not been allocated (because there
1057 are no named values in the function).<p>
1059 <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTableSure()</tt><p>
1061 Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a> for this
1062 <tt>Module</tt> or allocate a new <a
1063 href="#SymbolTable"><tt>SymbolTable</tt></a> if one is not already around. This
1064 should only be used when adding elements to the <a
1065 href="#SymbolTable"><tt>SymbolTable</tt></a>, so that empty symbol tables are
1066 not left laying around.<p>
1069 <!-- Convenience methods -->
1072 <li><tt><a href="#Function">Function</a> *getFunction(const std::string &Name, const <a href="#FunctionType">FunctionType</a> *Ty)</tt><p>
1074 Look up the specified function in the <tt>Module</tt> <a
1075 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
1079 <li><tt><a href="#Function">Function</a> *getOrInsertFunction(const std::string
1080 &Name, const <a href="#FunctionType">FunctionType</a> *T)</tt><p>
1082 Look up the specified function in the <tt>Module</tt> <a
1083 href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, add an
1084 external declaration for the function and return it.<p>
1087 <li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt><p>
1089 If there is at least one entry in the <a
1090 href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
1091 href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
1095 <li><tt>bool addTypeName(const std::string &Name, const <a href="#Type">Type</a>
1098 Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a> mapping
1099 <tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this name, true
1100 is returned and the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is not
1104 <!-- ======================================================================= -->
1105 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1106 <tr><td> </td><td width="100%">
1107 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1108 <a name="Constant">The <tt>Constant</tt> class and subclasses</a>
1109 </b></font></td></tr></table><ul>
1111 Constant represents a base class for different types of constants. It is
1112 subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
1113 ConstantArray etc for representing the various types of Constants.<p>
1116 <!-- _______________________________________________________________________ -->
1117 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1119 <li><tt>bool isConstantExpr()</tt>: Returns true if it is a ConstantExpr
1124 \subsection{Important Subclasses of Constant}
1126 <li>ConstantSInt : This subclass of Constant represents a signed integer constant.
1128 <li><tt>int64_t getValue () const</tt>: Returns the underlying value of this constant.
1130 <li>ConstantUInt : This class represents an unsigned integer.
1132 <li><tt>uint64_t getValue () const</tt>: Returns the underlying value of this constant.
1134 <li>ConstantFP : This class represents a floating point constant.
1136 <li><tt>double getValue () const</tt>: Returns the underlying value of this constant.
1138 <li>ConstantBool : This represents a boolean constant.
1140 <li><tt>bool getValue () const</tt>: Returns the underlying value of this constant.
1142 <li>ConstantArray : This represents a constant array.
1144 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1146 <li>ConstantStruct : This represents a constant struct.
1148 <li><tt>const std::vector<Use> &getValues() const</tt>: Returns a Vecotr of component constants that makeup this array.
1150 <li>ConstantPointerRef : This represents a constant pointer value that is initialized to point to a global value, which lies at a constant fixed address.
1152 <li><tt>GlobalValue *getValue()</tt>: Returns the global value to which this pointer is pointing to.
1157 <!-- ======================================================================= -->
1158 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1159 <tr><td> </td><td width="100%">
1160 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1161 <a name="Type">The <tt>Type</tt> class and Derived Types</a>
1162 </b></font></td></tr></table><ul>
1164 Type as noted earlier is also a subclass of a Value class. Any primitive
1165 type (like int, short etc) in LLVM is an instance of Type Class. All
1166 other types are instances of subclasses of type like FunctionType,
1167 ArrayType etc. DerivedType is the interface for all such dervied types
1168 including FunctionType, ArrayType, PointerType, StructType. Types can have
1169 names. They can be recursive (StructType). There exists exactly one instance
1170 of any type structure at a time. This allows using pointer equality of Type *s for comparing types.
1172 <!-- _______________________________________________________________________ -->
1173 </ul><h4><a name="m_Value"><hr size=0>Important Public Methods</h4><ul>
1175 <li><tt>PrimitiveID getPrimitiveID () const</tt>: Returns the base type of the type.
1176 <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.
1177 <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.
1178 <li><tt> bool isInteger () const</tt>: Equilivent to isSigned() || isUnsigned(), but with only a single virtual function invocation.
1179 <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.
1181 <li><tt>bool isFloatingPoint ()</tt>: Return true if this is one of the two floating point types.
1182 <li><tt>bool isRecursive () const</tt>: Returns rue if the type graph contains a cycle.
1183 <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.
1184 <li><tt>bool isPrimitiveType () const</tt>: Returns true if it is a primitive type.
1185 <li><tt>bool isDerivedType () const</tt>: Returns true if it is a derived type.
1186 <li><tt>const Type * getContainedType (unsigned i) const</tt>:
1187 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.
1188 <li><tt>unsigned getNumContainedTypes () const</tt>: Return the number of types in the derived type.
1192 \subsection{Derived Types}
1194 <li>SequentialType : This is subclassed by ArrayType and PointerType
1196 <li><tt>const Type * getElementType () const</tt>: Returns the type of each of the elements in the sequential type.
1198 <li>ArrayType : This is a subclass of SequentialType and defines interface for array types.
1200 <li><tt>unsigned getNumElements () const</tt>: Returns the number of elements in the array.
1202 <li>PointerType : Subclass of SequentialType for pointer types.
1203 <li>StructType : subclass of DerivedTypes for struct types
1204 <li>FunctionType : subclass of DerivedTypes for function types.
1207 <li><tt>bool isVarArg () const</tt>: Returns true if its a vararg function
1208 <li><tt> const Type * getReturnType () const</tt>: Returns the return type of the function.
1209 <li><tt> const ParamTypes &getParamTypes () const</tt>: Returns a vector of parameter types.
1210 <li><tt>const Type * getParamType (unsigned i)</tt>: Returns the type of the ith parameter.
1211 <li><tt> const unsigned getNumParams () const</tt>: Returns the number of formal parameters.
1218 <!-- ======================================================================= -->
1219 </ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1220 <tr><td> </td><td width="100%">
1221 <font color="#EEEEFF" face="Georgia,Palatino"><b>
1222 <a name="Argument">The <tt>Argument</tt> class</a>
1223 </b></font></td></tr></table><ul>
1225 This subclass of Value defines the interface for incoming formal arguments to a
1226 function. A Function maitanis a list of its formal arguments. An argument has a
1227 pointer to the parent Function.
1232 <!-- *********************************************************************** -->
1234 <!-- *********************************************************************** -->
1237 <address>By: <a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
1238 <a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
1239 <!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
1240 <!-- hhmts start -->
1241 Last modified: Fri Sep 6 16:37:49 EDT 2002
1243 </font></body></html>