<li><a href="#introduction">Introduction</a></li>
<li><a href="#general">General Information</a>
<ul>
- <li><a href="#stl">The C++ Standard Template Library</a><!--
- <li>The <tt>-time-passes</tt> option
- <li>How to use the LLVM Makefile system
- <li>How to write a regression test
---> </li>
+ <li><a href="#stl">The C++ Standard Template Library</a></li>
+<!--
+ <li>The <tt>-time-passes</tt> option</li>
+ <li>How to use the LLVM Makefile system</li>
+ <li>How to write a regression test</li>
+
+-->
</ul>
</li>
<li><a href="#apis">Important and useful LLVM APIs</a>
<ul>
<li><a href="#isa">The <tt>isa<></tt>, <tt>cast<></tt>
and <tt>dyn_cast<></tt> templates</a> </li>
- <li><a href="#DEBUG">The <tt>DEBUG()</tt> macro & <tt>-debug</tt>
+ <li><a href="#DEBUG">The <tt>DEBUG()</tt> macro and <tt>-debug</tt>
option</a>
<ul>
<li><a href="#DEBUG_TYPE">Fine grained debug info with <tt>DEBUG_TYPE</tt>
</ul>
</li>
<li><a href="#Statistic">The <tt>Statistic</tt> template & <tt>-stats</tt>
-option</a><!--
- <li>The <tt>InstVisitor</tt> template
- <li>The general graph API
---> </li>
+option</a></li>
+<!--
+ <li>The <tt>InstVisitor</tt> template
+ <li>The general graph API
+-->
+ <li><a href="#ViewGraph">Viewing graphs while debugging code</a></li>
</ul>
</li>
<li><a href="#common">Helpful Hints for Common Operations</a>
<li><a href="#schanges_replacing">Replacing an <tt>Instruction</tt>
with another <tt>Value</tt></a> </li>
</ul>
+ </li>
<!--
<li>Working with the Control Flow Graph
<ul>
<li>
<li>
</ul>
---> </li>
+-->
</ul>
</li>
+
+ <li><a href="#advanced">Advanced Topics</a>
+ <ul>
+ <li><a href="#TypeResolve">LLVM Type Resolution</a>
+ <ul>
+ <li><a href="#BuildRecType">Basic Recursive Type Construction</a></li>
+ <li><a href="#refineAbstractTypeTo">The <tt>refineAbstractTypeTo</tt> method</a></li>
+ <li><a href="#PATypeHolder">The PATypeHolder Class</a></li>
+ <li><a href="#AbstractTypeUser">The AbstractTypeUser Class</a></li>
+ </ul></li>
+
+ <li><a href="#SymbolTable">The <tt>SymbolTable</tt> class </a></li>
+ </ul></li>
+
<li><a href="#coreclasses">The Core LLVM Class Hierarchy Reference</a>
<ul>
- <li><a href="#Value">The <tt>Value</tt> class</a>
- <ul>
- <li><a href="#User">The <tt>User</tt> class</a>
+ <li><a href="#Value">The <tt>Value</tt> class</a>
<ul>
- <li><a href="#Instruction">The <tt>Instruction</tt> class</a>
+ <li><a href="#User">The <tt>User</tt> class</a>
<ul>
- <li><a href="#GetElementPtrInst">The <tt>GetElementPtrInst</tt>
- class</a></li>
- </ul></li>
- <li><a href="#Module">The <tt>Module</tt> class</a></li>
- <li><a href="#Constant">The <tt>Constant</tt> class</a>
- <ul>
- <li><a href="#GlobalValue">The <tt>GlobalValue</tt> class</a>
- <ul>
- <li><a href="#BasicBlock">The <tt>BasicBlock</tt>class</a></li>
- <li><a href="#Function">The <tt>Function</tt> class</a></li>
- <li><a href="#GlobalVariable">The <tt>GlobalVariable</tt> class
- </a></li>
- </ul></li>
+ <li><a href="#Instruction">The <tt>Instruction</tt> class</a>
+ <ul>
+ <li><a href="#GetElementPtrInst">The <tt>GetElementPtrInst</tt> class</a></li>
+ </ul>
+ </li>
+ <li><a href="#Module">The <tt>Module</tt> class</a></li>
+ <li><a href="#Constant">The <tt>Constant</tt> class</a>
+ <ul>
+ <li><a href="#GlobalValue">The <tt>GlobalValue</tt> class</a>
+ <ul>
+ <li><a href="#BasicBlock">The <tt>BasicBlock</tt>class</a></li>
+ <li><a href="#Function">The <tt>Function</tt> class</a></li>
+ <li><a href="#GlobalVariable">The <tt>GlobalVariable</tt> class</a></li>
+ </ul>
+ </li>
+ </ul>
+ </li>
</ul>
</li>
<li><a href="#Type">The <tt>Type</tt> class</a> </li>
<li><a href="#Argument">The <tt>Argument</tt> class</a></li>
- </ul></li>
- </ul></li>
- <li><a href="#SymbolTable">The <tt>SymbolTable</tt> class </a></li>
- <li>The <tt>ilist</tt> and <tt>iplist</tt> classes
- <ul>
- <li>Creating, inserting, moving and deleting from LLVM lists </li>
- </ul>
- </li>
- <li>Important iterator invalidation semantics to be aware of.</li>
+ </ul>
+ </li>
+ </ul>
</li>
</ol>
<li><a href="http://www.research.att.com/%7Ebs/C++.html">Bjarne Stroustrup's C++
Page</a></li>
-<li><a href="http://www.linux.com.cn/Bruce_Eckel/TICPPv2/Contents.htm">
+<li><a href="http://64.78.49.204/">
Bruce Eckel's Thinking in C++, 2nd ed. Volume 2 Revision 4.0 (even better, get
the book).</a></li>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="isa">The isa<>, cast<> and dyn_cast<> templates</a>
+ <a name="isa">The <tt>isa<></tt>, <tt>cast<></tt> and
+ <tt>dyn_cast<></tt> templates</a>
</div>
<div class="doc_text">
the fact that <tt>dynamic_cast<></tt> only works on classes that
have a v-table). Because they are used so often, you must know what they
do and how they work. All of these templates are defined in the <a
- href="/doxygen/Casting_8h-source.html"><tt>Support/Casting.h</tt></a>
+ href="/doxygen/Casting_8h-source.html"><tt>llvm/Support/Casting.h</tt></a>
file (note that you very rarely have to include this file directly).</p>
<dl>
<dt><tt>isa<></tt>: </dt>
- <dd>The <tt>isa<></tt> operator works exactly like the Java
+ <dd><p>The <tt>isa<></tt> operator works exactly like the Java
"<tt>instanceof</tt>" operator. It returns true or false depending on whether
a reference or pointer points to an instance of the specified class. This can
- be very useful for constraint checking of various sorts (example below).</dd>
+ be very useful for constraint checking of various sorts (example below).</p>
+ </dd>
<dt><tt>cast<></tt>: </dt>
- <dd>The <tt>cast<></tt> operator is a "checked cast" operation. It
+ <dd><p>The <tt>cast<></tt> operator is a "checked cast" operation. It
converts a pointer or reference from a base class to a derived cast, causing
an assertion failure if it is not really an instance of the right type. This
should be used in cases where you have some information that makes you believe
that something is of the right type. An example of the <tt>isa<></tt>
- and <tt>cast<></tt> template is:
+ and <tt>cast<></tt> template is:</p>
- <pre>
- static bool isLoopInvariant(const <a href="#Value">Value</a> *V, const Loop *L) {
- if (isa<<a href="#Constant">Constant</a>>(V) || isa<<a href="#Argument">Argument</a>>(V) || isa<<a href="#GlobalValue">GlobalValue</a>>(V))
- return true;
+<div class="doc_code">
+<pre>
+static bool isLoopInvariant(const <a href="#Value">Value</a> *V, const Loop *L) {
+ if (isa<<a href="#Constant">Constant</a>>(V) || isa<<a href="#Argument">Argument</a>>(V) || isa<<a href="#GlobalValue">GlobalValue</a>>(V))
+ return true;
- <i>// Otherwise, it must be an instruction...</i>
+ // <i>Otherwise, it must be an instruction...</i>
return !L->contains(cast<<a href="#Instruction">Instruction</a>>(V)->getParent());
- </pre>
+}
+</pre>
+</div>
<p>Note that you should <b>not</b> use an <tt>isa<></tt> test followed
by a <tt>cast<></tt>, for that use the <tt>dyn_cast<></tt>
<dt><tt>dyn_cast<></tt>:</dt>
- <dd>The <tt>dyn_cast<></tt> operator is a "checking cast" operation. It
- checks to see if the operand is of the specified type, and if so, returns a
+ <dd><p>The <tt>dyn_cast<></tt> operator is a "checking cast" operation.
+ It checks to see if the operand is of the specified type, and if so, returns a
pointer to it (this operator does not work with references). If the operand is
not of the correct type, a null pointer is returned. Thus, this works very
- much like the <tt>dynamic_cast</tt> operator in C++, and should be used in the
- same circumstances. Typically, the <tt>dyn_cast<></tt> operator is used
- in an <tt>if</tt> statement or some other flow control statement like this:
-
- <pre>
- if (<a href="#AllocationInst">AllocationInst</a> *AI = dyn_cast<<a href="#AllocationInst">AllocationInst</a>>(Val)) {
- ...
- }
- </pre>
+ much like the <tt>dynamic_cast<></tt> operator in C++, and should be
+ used in the same circumstances. Typically, the <tt>dyn_cast<></tt>
+ operator is used in an <tt>if</tt> statement or some other flow control
+ statement like this:</p>
+
+<div class="doc_code">
+<pre>
+if (<a href="#AllocationInst">AllocationInst</a> *AI = dyn_cast<<a href="#AllocationInst">AllocationInst</a>>(Val)) {
+ // <i>...</i>
+}
+</pre>
+</div>
- <p> This form of the <tt>if</tt> statement effectively combines together a
- call to <tt>isa<></tt> and a call to <tt>cast<></tt> into one
- statement, which is very convenient.</p>
-
- <p> Another common example is:</p>
-
- <pre>
- <i>// Loop over all of the phi nodes in a basic block</i>
- BasicBlock::iterator BBI = BB->begin();
- for (; <a href="#PhiNode">PHINode</a> *PN = dyn_cast<<a href="#PHINode">PHINode</a>>(BBI); ++BBI)
- std::cerr << *PN;
- </pre>
+ <p>This form of the <tt>if</tt> statement effectively combines together a call
+ to <tt>isa<></tt> and a call to <tt>cast<></tt> into one
+ statement, which is very convenient.</p>
-
<p>Note that the <tt>dyn_cast<></tt> operator, like C++'s
- <tt>dynamic_cast</tt> or Java's <tt>instanceof</tt> operator, can be abused.
- In particular you should not use big chained <tt>if/then/else</tt> blocks to
- check for lots of different variants of classes. If you find yourself
- wanting to do this, it is much cleaner and more efficient to use the
- InstVisitor class to dispatch over the instruction type directly.</p>
+ <p>Note that the <tt>dyn_cast<></tt> operator, like C++'s
+ <tt>dynamic_cast<></tt> or Java's <tt>instanceof</tt> operator, can be
+ abused. In particular, you should not use big chained <tt>if/then/else</tt>
+ blocks to check for lots of different variants of classes. If you find
+ yourself wanting to do this, it is much cleaner and more efficient to use the
+ <tt>InstVisitor</tt> class to dispatch over the instruction type directly.</p>
- </dd>
+ </dd>
- <dt><tt>cast_or_null<></tt>: </dt>
-
- <dd>The <tt>cast_or_null<></tt> operator works just like the
- <tt>cast<></tt> operator, except that it allows for a null pointer as
- an argument (which it then propagates). This can sometimes be useful,
- allowing you to combine several null checks into one.</dd>
+ <dt><tt>cast_or_null<></tt>: </dt>
+
+ <dd><p>The <tt>cast_or_null<></tt> operator works just like the
+ <tt>cast<></tt> operator, except that it allows for a null pointer as an
+ argument (which it then propagates). This can sometimes be useful, allowing
+ you to combine several null checks into one.</p></dd>
- <dt><tt>dyn_cast_or_null<></tt>: </dt>
+ <dt><tt>dyn_cast_or_null<></tt>: </dt>
- <dd>The <tt>dyn_cast_or_null<></tt> operator works just like the
- <tt>dyn_cast<></tt> operator, except that it allows for a null pointer
- as an argument (which it then propagates). This can sometimes be useful,
- allowing you to combine several null checks into one.</dd>
+ <dd><p>The <tt>dyn_cast_or_null<></tt> operator works just like the
+ <tt>dyn_cast<></tt> operator, except that it allows for a null pointer
+ as an argument (which it then propagates). This can sometimes be useful,
+ allowing you to combine several null checks into one.</p></dd>
- </dl>
+</dl>
<p>These five templates can be used with any classes, whether they have a
v-table or not. To add support for these templates, you simply need to add
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="DEBUG">The <tt>DEBUG()</tt> macro & <tt>-debug</tt> option</a>
+ <a name="DEBUG">The <tt>DEBUG()</tt> macro and <tt>-debug</tt> option</a>
</div>
<div class="doc_text">
<p>Often when working on your pass you will put a bunch of debugging printouts
and other code into your pass. After you get it working, you want to remove
-it... but you may need it again in the future (to work out new bugs that you run
+it, but you may need it again in the future (to work out new bugs that you run
across).</p>
<p> Naturally, because of this, you don't want to delete the debug printouts,
but you don't want them to always be noisy. A standard compromise is to comment
them out, allowing you to enable them if you need them in the future.</p>
-<p>The "<tt><a href="/doxygen/Debug_8h-source.html">Support/Debug.h</a></tt>"
+<p>The "<tt><a href="/doxygen/Debug_8h-source.html">llvm/Support/Debug.h</a></tt>"
file provides a macro named <tt>DEBUG()</tt> that is a much nicer solution to
this problem. Basically, you can put arbitrary code into the argument of the
<tt>DEBUG</tt> macro, and it is only executed if '<tt>opt</tt>' (or any other
tool) is run with the '<tt>-debug</tt>' command line argument:</p>
- <pre> ... <br> DEBUG(std::cerr << "I am here!\n");<br> ...<br></pre>
+<div class="doc_code">
+<pre>
+DEBUG(std::cerr << "I am here!\n");
+</pre>
+</div>
<p>Then you can run your pass like this:</p>
- <pre> $ opt < a.bc > /dev/null -mypass<br> <no output><br> $ opt < a.bc > /dev/null -mypass -debug<br> I am here!<br> $<br></pre>
+<div class="doc_code">
+<pre>
+$ opt < a.bc > /dev/null -mypass
+<i><no output></i>
+$ opt < a.bc > /dev/null -mypass -debug
+I am here!
+</pre>
+</div>
<p>Using the <tt>DEBUG()</tt> macro instead of a home-brewed solution allows you
to not have to create "yet another" command line option for the debug output for
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="DEBUG_TYPE">Fine grained debug info with <tt>DEBUG_TYPE()</tt> and
+ <a name="DEBUG_TYPE">Fine grained debug info with <tt>DEBUG_TYPE</tt> and
the <tt>-debug-only</tt> option</a>
</div>
control, you define the <tt>DEBUG_TYPE</tt> macro and the <tt>-debug</tt> only
option as follows:</p>
- <pre> ...<br> DEBUG(std::cerr << "No debug type\n");<br> #undef DEBUG_TYPE<br> #define DEBUG_TYPE "foo"<br> DEBUG(std::cerr << "'foo' debug type\n");<br> #undef DEBUG_TYPE<br> #define DEBUG_TYPE "bar"<br> DEBUG(std::cerr << "'bar' debug type\n");<br> #undef DEBUG_TYPE<br> #define DEBUG_TYPE ""<br> DEBUG(std::cerr << "No debug type (2)\n");<br> ...<br></pre>
+<div class="doc_code">
+<pre>
+DEBUG(std::cerr << "No debug type\n");
+#undef DEBUG_TYPE
+#define DEBUG_TYPE "foo"
+DEBUG(std::cerr << "'foo' debug type\n");
+#undef DEBUG_TYPE
+#define DEBUG_TYPE "bar"
+DEBUG(std::cerr << "'bar' debug type\n");
+#undef DEBUG_TYPE
+#define DEBUG_TYPE ""
+DEBUG(std::cerr << "No debug type (2)\n");
+</pre>
+</div>
<p>Then you can run your pass like this:</p>
- <pre> $ opt < a.bc > /dev/null -mypass<br> <no output><br> $ opt < a.bc > /dev/null -mypass -debug<br> No debug type<br> 'foo' debug type<br> 'bar' debug type<br> No debug type (2)<br> $ opt < a.bc > /dev/null -mypass -debug-only=foo<br> 'foo' debug type<br> $ opt < a.bc > /dev/null -mypass -debug-only=bar<br> 'bar' debug type<br> $<br></pre>
+<div class="doc_code">
+<pre>
+$ opt < a.bc > /dev/null -mypass
+<i><no output></i>
+$ opt < a.bc > /dev/null -mypass -debug
+No debug type
+'foo' debug type
+'bar' debug type
+No debug type (2)
+$ opt < a.bc > /dev/null -mypass -debug-only=foo
+'foo' debug type
+$ opt < a.bc > /dev/null -mypass -debug-only=bar
+'bar' debug type
+</pre>
+</div>
<p>Of course, in practice, you should only set <tt>DEBUG_TYPE</tt> at the top of
a file, to specify the debug type for the entire module (if you do this before
-you <tt>#include "Support/Debug.h"</tt>, you don't have to insert the ugly
+you <tt>#include "llvm/Support/Debug.h"</tt>, you don't have to insert the ugly
<tt>#undef</tt>'s). Also, you should use names more meaningful than "foo" and
"bar", because there is no system in place to ensure that names do not
conflict. If two different modules use the same string, they will all be turned
<div class="doc_text">
<p>The "<tt><a
-href="/doxygen/Statistic_8h-source.html">Support/Statistic.h</a></tt>" file
+href="/doxygen/Statistic_8h-source.html">llvm/ADT/Statistic.h</a></tt>" file
provides a template named <tt>Statistic</tt> that is used as a unified way to
keep track of what the LLVM compiler is doing and how effective various
optimizations are. It is useful to see what optimizations are contributing to
it are as follows:</p>
<ol>
- <li>Define your statistic like this:
- <pre>static Statistic<> NumXForms("mypassname", "The # of times I did stuff");<br></pre>
+ <li><p>Define your statistic like this:</p>
+
+<div class="doc_code">
+<pre>
+static Statistic<> NumXForms("mypassname", "The # of times I did stuff");
+</pre>
+</div>
<p>The <tt>Statistic</tt> template can emulate just about any data-type,
but if you do not specify a template argument, it defaults to acting like
an unsigned int counter (this is usually what you want).</p></li>
- <li>Whenever you make a transformation, bump the counter:
- <pre> ++NumXForms; // I did stuff<br></pre>
+ <li><p>Whenever you make a transformation, bump the counter:</p>
+
+<div class="doc_code">
+<pre>
+++NumXForms; // <i>I did stuff!</i>
+</pre>
+</div>
+
</li>
</ol>
<p>That's all you have to do. To get '<tt>opt</tt>' to print out the
statistics gathered, use the '<tt>-stats</tt>' option:</p>
- <pre> $ opt -stats -mypassname < program.bc > /dev/null<br> ... statistic output ...<br></pre>
+<div class="doc_code">
+<pre>
+$ opt -stats -mypassname < program.bc > /dev/null
+<i>... statistics output ...</i>
+</pre>
+</div>
<p> When running <tt>gccas</tt> on a C file from the SPEC benchmark
suite, it gives a report that looks like this:</p>
- <pre> 7646 bytecodewriter - Number of normal instructions<br> 725 bytecodewriter - Number of oversized instructions<br> 129996 bytecodewriter - Number of bytecode bytes written<br> 2817 raise - Number of insts DCEd or constprop'd<br> 3213 raise - Number of cast-of-self removed<br> 5046 raise - Number of expression trees converted<br> 75 raise - Number of other getelementptr's formed<br> 138 raise - Number of load/store peepholes<br> 42 deadtypeelim - Number of unused typenames removed from symtab<br> 392 funcresolve - Number of varargs functions resolved<br> 27 globaldce - Number of global variables removed<br> 2 adce - Number of basic blocks removed<br> 134 cee - Number of branches revectored<br> 49 cee - Number of setcc instruction eliminated<br> 532 gcse - Number of loads removed<br> 2919 gcse - Number of instructions removed<br> 86 indvars - Number of canonical indvars added<br> 87 indvars - Number of aux indvars removed<br> 25 instcombine - Number of dead inst eliminate<br> 434 instcombine - Number of insts combined<br> 248 licm - Number of load insts hoisted<br> 1298 licm - Number of insts hoisted to a loop pre-header<br> 3 licm - Number of insts hoisted to multiple loop preds (bad, no loop pre-header)<br> 75 mem2reg - Number of alloca's promoted<br> 1444 cfgsimplify - Number of blocks simplified<br></pre>
+<div class="doc_code">
+<pre>
+ 7646 bytecodewriter - Number of normal instructions
+ 725 bytecodewriter - Number of oversized instructions
+ 129996 bytecodewriter - Number of bytecode bytes written
+ 2817 raise - Number of insts DCEd or constprop'd
+ 3213 raise - Number of cast-of-self removed
+ 5046 raise - Number of expression trees converted
+ 75 raise - Number of other getelementptr's formed
+ 138 raise - Number of load/store peepholes
+ 42 deadtypeelim - Number of unused typenames removed from symtab
+ 392 funcresolve - Number of varargs functions resolved
+ 27 globaldce - Number of global variables removed
+ 2 adce - Number of basic blocks removed
+ 134 cee - Number of branches revectored
+ 49 cee - Number of setcc instruction eliminated
+ 532 gcse - Number of loads removed
+ 2919 gcse - Number of instructions removed
+ 86 indvars - Number of canonical indvars added
+ 87 indvars - Number of aux indvars removed
+ 25 instcombine - Number of dead inst eliminate
+ 434 instcombine - Number of insts combined
+ 248 licm - Number of load insts hoisted
+ 1298 licm - Number of insts hoisted to a loop pre-header
+ 3 licm - Number of insts hoisted to multiple loop preds (bad, no loop pre-header)
+ 75 mem2reg - Number of alloca's promoted
+ 1444 cfgsimplify - Number of blocks simplified
+</pre>
+</div>
<p>Obviously, with so many optimizations, having a unified framework for this
stuff is very nice. Making your pass fit well into the framework makes it more
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="ViewGraph">Viewing graphs while debugging code</a>
+</div>
+
+<div class="doc_text">
+
+<p>Several of the important data structures in LLVM are graphs: for example
+CFGs made out of LLVM <a href="#BasicBlock">BasicBlock</a>s, CFGs made out of
+LLVM <a href="CodeGenerator.html#machinebasicblock">MachineBasicBlock</a>s, and
+<a href="CodeGenerator.html#selectiondag_intro">Instruction Selection
+DAGs</a>. In many cases, while debugging various parts of the compiler, it is
+nice to instantly visualize these graphs.</p>
+
+<p>LLVM provides several callbacks that are available in a debug build to do
+exactly that. If you call the <tt>Function::viewCFG()</tt> method, for example,
+the current LLVM tool will pop up a window containing the CFG for the function
+where each basic block is a node in the graph, and each node contains the
+instructions in the block. Similarly, there also exists
+<tt>Function::viewCFGOnly()</tt> (does not include the instructions), the
+<tt>MachineFunction::viewCFG()</tt> and <tt>MachineFunction::viewCFGOnly()</tt>,
+and the <tt>SelectionDAG::viewGraph()</tt> methods. Within GDB, for example,
+you can usually use something like <tt>call DAG.viewGraph()</tt> to pop
+up a window. Alternatively, you can sprinkle calls to these functions in your
+code in places you want to debug.</p>
+
+<p>Getting this to work requires a small amount of configuration. On Unix
+systems with X11, install the <a href="http://www.graphviz.org">graphviz</a>
+toolkit, and make sure 'dot' and 'gv' are in your path. If you are running on
+Mac OS/X, download and install the Mac OS/X <a
+href="http://www.pixelglow.com/graphviz/">Graphviz program</a>, and add
+<tt>/Applications/Graphviz.app/Contents/MacOS/</tt> (or whereever you install
+it) to your path. Once in your system and path are set up, rerun the LLVM
+configure script and rebuild LLVM to enable this functionality.</p>
+
+<p><tt>SelectionDAG</tt> has been extended to make it easier to locate
+<i>interesting</i> nodes in large complex graphs. From gdb, if you
+<tt>call DAG.setGraphColor(<i>node</i>, "<i>color</i>")</tt>, then the
+next <tt>call DAG.viewGraph()</tt> would hilight the node in the
+specified color (choices of colors can be found at <a
+href="http://www.graphviz.org/doc/info/colors.html">Colors<a>.) More
+complex node attributes can be provided with <tt>call
+DAG.setGraphAttrs(<i>node</i>, "<i>attributes</i>")</tt> (choices can be
+found at <a href="http://www.graphviz.org/doc/info/attrs.html">Graph
+Attributes</a>.) If you want to restart and clear all the current graph
+attributes, then you can <tt>call DAG.clearGraphAttrs()</tt>. </p>
+
+</div>
+
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="common">Helpful Hints for Common Operations</a>
an example that prints the name of a <tt>BasicBlock</tt> and the number of
<tt>Instruction</tt>s it contains:</p>
- <pre> // func is a pointer to a Function instance<br> for (Function::iterator i = func->begin(), e = func->end(); i != e; ++i) {<br><br> // print out the name of the basic block if it has one, and then the<br> // number of instructions that it contains<br><br> cerr << "Basic block (name=" << i->getName() << ") has " <br> << i->size() << " instructions.\n";<br> }<br></pre>
+<div class="doc_code">
+<pre>
+// <i>func is a pointer to a Function instance</i>
+for (Function::iterator i = func->begin(), e = func->end(); i != e; ++i)
+ // <i>Print out the name of the basic block if it has one, and then the</i>
+ // <i>number of instructions that it contains</i>
+ std::cerr << "Basic block (name=" << i->getName() << ") has "
+ << i->size() << " instructions.\n";
+</pre>
+</div>
<p>Note that i can be used as if it were a pointer for the purposes of
invoking member functions of the <tt>Instruction</tt> class. This is
<tt>BasicBlock</tt>s. Here's a code snippet that prints out each instruction in
a <tt>BasicBlock</tt>:</p>
- <pre> // blk is a pointer to a BasicBlock instance<br> for (BasicBlock::iterator i = blk->begin(), e = blk->end(); i != e; ++i)<br> // the next statement works since operator<<(ostream&,...) <br> // is overloaded for Instruction&<br> cerr << *i << "\n";<br></pre>
+<div class="doc_code">
+<pre>
+// <i>blk is a pointer to a BasicBlock instance</i>
+for (BasicBlock::iterator i = blk->begin(), e = blk->end(); i != e; ++i)
+ // <i>The next statement works since operator<<(ostream&,...)</i>
+ // <i>is overloaded for Instruction&</i>
+ std::cerr << *i << "\n";
+</pre>
+</div>
<p>However, this isn't really the best way to print out the contents of a
<tt>BasicBlock</tt>! Since the ostream operators are overloaded for virtually
anything you'll care about, you could have just invoked the print routine on the
-basic block itself: <tt>cerr << *blk << "\n";</tt>.</p>
-
-<p>Note that currently operator<< is implemented for <tt>Value*</tt>, so
-it will print out the contents of the pointer, instead of the pointer value you
-might expect. This is a deprecated interface that will be removed in the
-future, so it's best not to depend on it. To print out the pointer value for
-now, you must cast to <tt>void*</tt>.</p>
+basic block itself: <tt>std::cerr << *blk << "\n";</tt>.</p>
</div>
and then instantiate <tt>InstIterator</tt>s explicitly in your code. Here's a
small example that shows how to dump all instructions in a function to the standard error stream:<p>
- <pre>#include "<a href="/doxygen/InstIterator_8h-source.html">llvm/Support/InstIterator.h</a>"<br>...<br>// Suppose F is a ptr to a function<br>for (inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)<br> cerr << *i << "\n";<br></pre>
-Easy, isn't it? You can also use <tt>InstIterator</tt>s to fill a
+<div class="doc_code">
+<pre>
+#include "<a href="/doxygen/InstIterator_8h-source.html">llvm/Support/InstIterator.h</a>"
+
+// <i>F is a ptr to a Function instance</i>
+for (inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)
+ std::cerr << *i << "\n";
+</pre>
+</div>
+
+<p>Easy, isn't it? You can also use <tt>InstIterator</tt>s to fill a
worklist with its initial contents. For example, if you wanted to
initialize a worklist to contain all instructions in a <tt>Function</tt>
-F, all you would need to do is something like:
- <pre>std::set<Instruction*> worklist;<br>worklist.insert(inst_begin(F), inst_end(F));<br></pre>
+F, all you would need to do is something like:</p>
+
+<div class="doc_code">
+<pre>
+std::set<Instruction*> worklist;
+worklist.insert(inst_begin(F), inst_end(F));
+</pre>
+</div>
<p>The STL set <tt>worklist</tt> would now contain all instructions in the
<tt>Function</tt> pointed to by F.</p>
Assuming that <tt>i</tt> is a <tt>BasicBlock::iterator</tt> and <tt>j</tt>
is a <tt>BasicBlock::const_iterator</tt>:</p>
- <pre> Instruction& inst = *i; // grab reference to instruction reference<br> Instruction* pinst = &*i; // grab pointer to instruction reference<br> const Instruction& inst = *j;<br></pre>
+<div class="doc_code">
+<pre>
+Instruction& inst = *i; // <i>Grab reference to instruction reference</i>
+Instruction* pinst = &*i; // <i>Grab pointer to instruction reference</i>
+const Instruction& inst = *j;
+</pre>
+</div>
<p>However, the iterators you'll be working with in the LLVM framework are
special: they will automatically convert to a ptr-to-instance type whenever they
(behind the scenes, this is a result of overloading casting mechanisms). Thus
the last line of the last example,</p>
- <pre>Instruction* pinst = &*i;</pre>
+<div class="doc_code">
+<pre>
+Instruction* pinst = &*i;
+</pre>
+</div>
<p>is semantically equivalent to</p>
- <pre>Instruction* pinst = i;</pre>
+<div class="doc_code">
+<pre>
+Instruction* pinst = i;
+</pre>
+</div>
<p>It's also possible to turn a class pointer into the corresponding iterator,
and this is a constant time operation (very efficient). The following code
iterators. By using these, you can explicitly grab the iterator of something
without actually obtaining it via iteration over some structure:</p>
- <pre>void printNextInstruction(Instruction* inst) {<br> BasicBlock::iterator it(inst);<br> ++it; // after this line, it refers to the instruction after *inst.<br> if (it != inst->getParent()->end()) cerr << *it << "\n";<br>}<br></pre>
+<div class="doc_code">
+<pre>
+void printNextInstruction(Instruction* inst) {
+ BasicBlock::iterator it(inst);
+ ++it; // <i>After this line, it refers to the instruction after *inst</i>
+ if (it != inst->getParent()->end()) std::cerr << *it << "\n";
+}
+</pre>
+</div>
</div>
you'd do it if you didn't have <tt>InstVisitor</tt> around. In pseudocode, this
is what we want to do:</p>
- <pre>initialize callCounter to zero<br>for each Function f in the Module<br> for each BasicBlock b in f<br> for each Instruction i in b<br> if (i is a CallInst and calls the given function)<br> increment callCounter<br></pre>
+<div class="doc_code">
+<pre>
+initialize callCounter to zero
+for each Function f in the Module
+ for each BasicBlock b in f
+ for each Instruction i in b
+ if (i is a CallInst and calls the given function)
+ increment callCounter
+</pre>
+</div>
-<p>And the actual code is (remember, since we're writing a
+<p>And the actual code is (remember, because we're writing a
<tt>FunctionPass</tt>, our <tt>FunctionPass</tt>-derived class simply has to
-override the <tt>runOnFunction</tt> method...):</p>
+override the <tt>runOnFunction</tt> method):</p>
+
+<div class="doc_code">
+<pre>
+Function* targetFunc = ...;
+
+class OurFunctionPass : public FunctionPass {
+ public:
+ OurFunctionPass(): callCounter(0) { }
- <pre>Function* targetFunc = ...;<br><br>class OurFunctionPass : public FunctionPass {<br> public:<br> OurFunctionPass(): callCounter(0) { }<br><br> virtual runOnFunction(Function& F) {<br> for (Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {<br> for (BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {<br> if (<a
- href="#CallInst">CallInst</a>* callInst = <a href="#isa">dyn_cast</a><<a
- href="#CallInst">CallInst</a>>(&*i)) {<br> // we know we've encountered a call instruction, so we<br> // need to determine if it's a call to the<br> // function pointed to by m_func or not.<br> <br> if (callInst->getCalledFunction() == targetFunc)<br> ++callCounter;<br> }<br> }<br> }<br> <br> private:<br> unsigned callCounter;<br>};<br></pre>
+ virtual runOnFunction(Function& F) {
+ for (Function::iterator b = F.begin(), be = F.end(); b != be; ++b) {
+ for (BasicBlock::iterator i = b->begin(); ie = b->end(); i != ie; ++i) {
+ if (<a href="#CallInst">CallInst</a>* callInst = <a href="#isa">dyn_cast</a><<a
+ href="#CallInst">CallInst</a>>(&*i)) {
+ // <i>We know we've encountered a call instruction, so we</i>
+ // <i>need to determine if it's a call to the</i>
+ // <i>function pointed to by m_func or not</i>
+
+ if (callInst->getCalledFunction() == targetFunc)
+ ++callCounter;
+ }
+ }
+ }
+ }
+
+ private:
+ unsigned callCounter;
+};
+</pre>
+</div>
</div>
most-specific common base class is <tt>Instruction</tt>, which includes lots of
less closely-related things. For these cases, LLVM provides a handy wrapper
class called <a
-href="http://llvm.cs.uiuc.edu/doxygen/classllvm_1_1CallSite.html"><tt>CallSite</tt></a>.
+href="http://llvm.org/doxygen/classllvm_1_1CallSite.html"><tt>CallSite</tt></a>.
It is essentially a wrapper around an <tt>Instruction</tt> pointer, with some
methods that provide functionality common to <tt>CallInst</tt>s and
<tt>InvokeInst</tt>s.</p>
<i>use</i> <tt>foo</tt> is as simple as iterating over the <i>def-use</i> chain
of <tt>F</tt>:</p>
- <pre>Function* F = ...;<br><br>for (Value::use_iterator i = F->use_begin(), e = F->use_end(); i != e; ++i) {<br> if (Instruction *Inst = dyn_cast<Instruction>(*i)) {<br> cerr << "F is used in instruction:\n";<br> cerr << *Inst << "\n";<br> }<br>}<br></pre>
+<div class="doc_code">
+<pre>
+Function* F = ...;
+
+for (Value::use_iterator i = F->use_begin(), e = F->use_end(); i != e; ++i)
+ if (Instruction *Inst = dyn_cast<Instruction>(*i)) {
+ std::cerr << "F is used in instruction:\n";
+ std::cerr << *Inst << "\n";
+ }
+</pre>
+</div>
<p>Alternately, it's common to have an instance of the <a
href="/doxygen/classllvm_1_1User.html">User Class</a> and need to know what
all of the values that a particular instruction uses (that is, the operands of
the particular <tt>Instruction</tt>):</p>
- <pre>Instruction* pi = ...;<br><br>for (User::op_iterator i = pi->op_begin(), e = pi->op_end(); i != e; ++i) {<br> Value* v = *i;<br> ...<br>}<br></pre>
+<div class="doc_code">
+<pre>
+Instruction* pi = ...;
+
+for (User::op_iterator i = pi->op_begin(), e = pi->op_end(); i != e; ++i) {
+ Value* v = *i;
+ // <i>...</i>
+}
+</pre>
+</div>
<!--
def-use chains ("finding all users of"): Value::use_begin/use_end
parameters. For example, an <tt>AllocaInst</tt> only <i>requires</i> a
(const-ptr-to) <tt>Type</tt>. Thus:</p>
-<pre>AllocaInst* ai = new AllocaInst(Type::IntTy);</pre>
+<div class="doc_code">
+<pre>
+AllocaInst* ai = new AllocaInst(Type::IntTy);
+</pre>
+</div>
<p>will create an <tt>AllocaInst</tt> instance that represents the allocation of
one integer in the current stack frame, at runtime. Each <tt>Instruction</tt>
<tt>Function</tt>, and I'm intending to use it within the same
<tt>Function</tt>. I might do:</p>
- <pre>AllocaInst* pa = new AllocaInst(Type::IntTy, 0, "indexLoc");</pre>
+<div class="doc_code">
+<pre>
+AllocaInst* pa = new AllocaInst(Type::IntTy, 0, "indexLoc");
+</pre>
+</div>
<p>where <tt>indexLoc</tt> is now the logical name of the instruction's
execution value, which is a pointer to an integer on the runtime stack.</p>
<tt>BasicBlock</tt>, and a newly-created instruction we wish to insert
before <tt>*pi</tt>, we do the following: </p>
- <pre> BasicBlock *pb = ...;<br> Instruction *pi = ...;<br> Instruction *newInst = new Instruction(...);<br> pb->getInstList().insert(pi, newInst); // inserts newInst before pi in pb<br></pre>
+<div class="doc_code">
+<pre>
+BasicBlock *pb = ...;
+Instruction *pi = ...;
+Instruction *newInst = new Instruction(...);
+
+pb->getInstList().insert(pi, newInst); // <i>Inserts newInst before pi in pb</i>
+</pre>
+</div>
<p>Appending to the end of a <tt>BasicBlock</tt> is so common that
the <tt>Instruction</tt> class and <tt>Instruction</tt>-derived
<tt>BasicBlock</tt> to be appended to. For example code that
looked like: </p>
- <pre> BasicBlock *pb = ...;<br> Instruction *newInst = new Instruction(...);<br> pb->getInstList().push_back(newInst); // appends newInst to pb<br></pre>
+<div class="doc_code">
+<pre>
+BasicBlock *pb = ...;
+Instruction *newInst = new Instruction(...);
+
+pb->getInstList().push_back(newInst); // <i>Appends newInst to pb</i>
+</pre>
+</div>
<p>becomes: </p>
- <pre> BasicBlock *pb = ...;<br> Instruction *newInst = new Instruction(..., pb);<br></pre>
+<div class="doc_code">
+<pre>
+BasicBlock *pb = ...;
+Instruction *newInst = new Instruction(..., pb);
+</pre>
+</div>
<p>which is much cleaner, especially if you are creating
long instruction streams.</p></li>
thing as the above code without being given a <tt>BasicBlock</tt> by doing:
</p>
- <pre> Instruction *pi = ...;<br> Instruction *newInst = new Instruction(...);<br> pi->getParent()->getInstList().insert(pi, newInst);<br></pre>
+<div class="doc_code">
+<pre>
+Instruction *pi = ...;
+Instruction *newInst = new Instruction(...);
+
+pi->getParent()->getInstList().insert(pi, newInst);
+</pre>
+</div>
<p>In fact, this sequence of steps occurs so frequently that the
<tt>Instruction</tt> class and <tt>Instruction</tt>-derived classes provide
<tt>Instruction</tt> constructor with a <tt>insertBefore</tt> (default)
parameter, the above code becomes:</p>
- <pre>Instruction* pi = ...;<br>Instruction* newInst = new Instruction(..., pi);<br></pre>
+<div class="doc_code">
+<pre>
+Instruction* pi = ...;
+Instruction* newInst = new Instruction(..., pi);
+</pre>
+</div>
<p>which is much cleaner, especially if you're creating a lot of
-instructions and adding them to <tt>BasicBlock</tt>s.</p></li>
+ instructions and adding them to <tt>BasicBlock</tt>s.</p></li>
</ul>
</div>
pointer to the basic block to get its list of instructions and then use the
erase function to remove your instruction. For example:</p>
- <pre> <a href="#Instruction">Instruction</a> *I = .. ;<br> <a
- href="#BasicBlock">BasicBlock</a> *BB = I->getParent();<br> BB->getInstList().erase(I);<br></pre>
+<div class="doc_code">
+<pre>
+<a href="#Instruction">Instruction</a> *I = .. ;
+<a href="#BasicBlock">BasicBlock</a> *BB = I->getParent();
+
+BB->getInstList().erase(I);
+</pre>
+</div>
</div>
<p>This function replaces all uses (within a basic block) of a given
instruction with a value, and then removes the original instruction. The
following example illustrates the replacement of the result of a particular
- <tt>AllocaInst</tt> that allocates memory for a single integer with an null
+ <tt>AllocaInst</tt> that allocates memory for a single integer with a null
pointer to an integer.</p>
- <pre>AllocaInst* instToReplace = ...;<br>BasicBlock::iterator ii(instToReplace);<br>ReplaceInstWithValue(instToReplace->getParent()->getInstList(), ii,<br> Constant::getNullValue(PointerType::get(Type::IntTy)));<br></pre></li>
+<div class="doc_code">
+<pre>
+AllocaInst* instToReplace = ...;
+BasicBlock::iterator ii(instToReplace);
+
+ReplaceInstWithValue(instToReplace->getParent()->getInstList(), ii,
+ Constant::getNullValue(PointerType::get(Type::IntTy)));
+</pre></div></li>
<li><tt>ReplaceInstWithInst</tt>
instruction. The following example illustrates the replacement of one
<tt>AllocaInst</tt> with another.</p>
- <pre>AllocaInst* instToReplace = ...;<br>BasicBlock::iterator ii(instToReplace);<br>ReplaceInstWithInst(instToReplace->getParent()->getInstList(), ii,<br> new AllocaInst(Type::IntTy, 0, "ptrToReplacedInt"));<br></pre></li>
+<div class="doc_code">
+<pre>
+AllocaInst* instToReplace = ...;
+BasicBlock::iterator ii(instToReplace);
+
+ReplaceInstWithInst(instToReplace->getParent()->getInstList(), ii,
+ new AllocaInst(Type::IntTy, 0, "ptrToReplacedInt"));
+</pre></div></li>
</ul>
<p><i>Replacing multiple uses of <tt>User</tt>s and <tt>Value</tt>s</i></p>
<!-- *********************************************************************** -->
<div class="doc_section">
- <a name="coreclasses">The Core LLVM Class Hierarchy Reference </a>
+ <a name="advanced">Advanced Topics</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
-
-<p>The Core LLVM classes are the primary means of representing the program
-being inspected or transformed. The core LLVM classes are defined in
-header files in the <tt>include/llvm/</tt> directory, and implemented in
-the <tt>lib/VMCore</tt> directory.</p>
-
+<p>
+This section describes some of the advanced or obscure API's that most clients
+do not need to be aware of. These API's tend manage the inner workings of the
+LLVM system, and only need to be accessed in unusual circumstances.
+</p>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="Value">The <tt>Value</tt> class</a>
+ <a name="TypeResolve">LLVM Type Resolution</a>
</div>
-<div>
+<div class="doc_text">
-<p><tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt>
-<br>
-doxygen info: <a href="/doxygen/structllvm_1_1Value.html">Value Class</a></p>
+<p>
+The LLVM type system has a very simple goal: allow clients to compare types for
+structural equality with a simple pointer comparison (aka a shallow compare).
+This goal makes clients much simpler and faster, and is used throughout the LLVM
+system.
+</p>
-<p>The <tt>Value</tt> class is the most important class in the LLVM Source
-base. It represents a typed value that may be used (among other things) as an
-operand to an instruction. There are many different types of <tt>Value</tt>s,
-such as <a href="#Constant"><tt>Constant</tt></a>s,<a
-href="#Argument"><tt>Argument</tt></a>s. Even <a
-href="#Instruction"><tt>Instruction</tt></a>s and <a
-href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.</p>
+<p>
+Unfortunately achieving this goal is not a simple matter. In particular,
+recursive types and late resolution of opaque types makes the situation very
+difficult to handle. Fortunately, for the most part, our implementation makes
+most clients able to be completely unaware of the nasty internal details. The
+primary case where clients are exposed to the inner workings of it are when
+building a recursive type. In addition to this case, the LLVM bytecode reader,
+assembly parser, and linker also have to be aware of the inner workings of this
+system.
+</p>
-<p>A particular <tt>Value</tt> may be used many times in the LLVM representation
-for a program. For example, an incoming argument to a function (represented
-with an instance of the <a href="#Argument">Argument</a> class) is "used" by
-every instruction in the function that references the argument. To keep track
-of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
-href="#User"><tt>User</tt></a>s that is using it (the <a
-href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
-graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
-def-use information in the program, and is accessible through the <tt>use_</tt>*
-methods, shown below.</p>
+<p>
+For our purposes below, we need three concepts. First, an "Opaque Type" is
+exactly as defined in the <a href="LangRef.html#t_opaque">language
+reference</a>. Second an "Abstract Type" is any type which includes an
+opaque type as part of its type graph (for example "<tt>{ opaque, int }</tt>").
+Third, a concrete type is a type that is not an abstract type (e.g. "<tt>[ int,
+float }</tt>").
+</p>
-<p>Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed,
-and this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
-method. In addition, all LLVM values can be named. The "name" of the
-<tt>Value</tt> is a symbolic string printed in the LLVM code:</p>
+</div>
- <pre> %<b>foo</b> = add int 1, 2<br></pre>
+<!-- ______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="BuildRecType">Basic Recursive Type Construction</a>
+</div>
-<p><a name="#nameWarning">The name of this instruction is "foo".</a> <b>NOTE</b>
-that the name of any value may be missing (an empty string), so names should
-<b>ONLY</b> be used for debugging (making the source code easier to read,
-debugging printouts), they should not be used to keep track of values or map
-between them. For this purpose, use a <tt>std::map</tt> of pointers to the
-<tt>Value</tt> itself instead.</p>
+<div class="doc_text">
-<p>One important aspect of LLVM is that there is no distinction between an SSA
-variable and the operation that produces it. Because of this, any reference to
-the value produced by an instruction (or the value available as an incoming
-argument, for example) is represented as a direct pointer to the instance of
-the class that
-represents this value. Although this may take some getting used to, it
-simplifies the representation and makes it easier to manipulate.</p>
+<p>
+Because the most common question is "how do I build a recursive type with LLVM",
+we answer it now and explain it as we go. Here we include enough to cause this
+to be emitted to an output .ll file:
+</p>
+<div class="doc_code">
+<pre>
+%mylist = type { %mylist*, int }
+</pre>
</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="m_Value">Important Public Members of the <tt>Value</tt> class</a>
-</div>
+<p>
+To build this, use the following LLVM APIs:
+</p>
-<div class="doc_text">
+<div class="doc_code">
+<pre>
+// <i>Create the initial outer struct</i>
+<a href="#PATypeHolder">PATypeHolder</a> StructTy = OpaqueType::get();
+std::vector<const Type*> Elts;
+Elts.push_back(PointerType::get(StructTy));
+Elts.push_back(Type::IntTy);
+StructType *NewSTy = StructType::get(Elts);
-<ul>
- <li><tt>Value::use_iterator</tt> - Typedef for iterator over the
-use-list<br>
- <tt>Value::use_const_iterator</tt> - Typedef for const_iterator over
-the use-list<br>
- <tt>unsigned use_size()</tt> - Returns the number of users of the
-value.<br>
- <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
- <tt>use_iterator use_begin()</tt> - Get an iterator to the start of
-the use-list.<br>
- <tt>use_iterator use_end()</tt> - Get an iterator to the end of the
-use-list.<br>
- <tt><a href="#User">User</a> *use_back()</tt> - Returns the last
-element in the list.
- <p> 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>
- </li>
- <li><tt><a href="#Type">Type</a> *getType() const</tt>
- <p>This method returns the Type of the Value.</p>
- </li>
- <li><tt>bool hasName() const</tt><br>
- <tt>std::string getName() const</tt><br>
- <tt>void setName(const std::string &Name)</tt>
- <p> This family of methods is used to access and assign a name to a <tt>Value</tt>,
-be aware of the <a href="#nameWarning">precaution above</a>.</p>
- </li>
- <li><tt>void replaceAllUsesWith(Value *V)</tt>
+// <i>At this point, NewSTy = "{ opaque*, int }". Tell VMCore that</i>
+// <i>the struct and the opaque type are actually the same.</i>
+cast<OpaqueType>(StructTy.get())-><a href="#refineAbstractTypeTo">refineAbstractTypeTo</a>(NewSTy);
- <p>This method traverses the use list of a <tt>Value</tt> changing all <a
- href="#User"><tt>User</tt>s</a> of the current value to refer to
- "<tt>V</tt>" instead. For example, if you detect that an instruction always
- produces a constant value (for example through constant folding), you can
- replace all uses of the instruction with the constant like this:</p>
+// <i>NewSTy is potentially invalidated, but StructTy (a <a href="#PATypeHolder">PATypeHolder</a>) is</i>
+// <i>kept up-to-date</i>
+NewSTy = cast<StructType>(StructTy.get());
- <pre> Inst->replaceAllUsesWith(ConstVal);<br></pre>
-</ul>
+// <i>Add a name for the type to the module symbol table (optional)</i>
+MyModule->addTypeName("mylist", NewSTy);
+</pre>
+</div>
+
+<p>
+This code shows the basic approach used to build recursive types: build a
+non-recursive type using 'opaque', then use type unification to close the cycle.
+The type unification step is performed by the <tt><a
+ref="#refineAbstractTypeTo">refineAbstractTypeTo</a></tt> method, which is
+described next. After that, we describe the <a
+href="#PATypeHolder">PATypeHolder class</a>.
+</p>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="User">The <tt>User</tt> class</a>
+<!-- ______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="refineAbstractTypeTo">The <tt>refineAbstractTypeTo</tt> method</a>
</div>
<div class="doc_text">
-
<p>
-<tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt><br>
-doxygen info: <a href="/doxygen/classllvm_1_1User.html">User Class</a><br>
-Superclass: <a href="#Value"><tt>Value</tt></a></p>
+The <tt>refineAbstractTypeTo</tt> method starts the type unification process.
+While this method is actually a member of the DerivedType class, it is most
+often used on OpaqueType instances. Type unification is actually a recursive
+process. After unification, types can become structurally isomorphic to
+existing types, and all duplicates are deleted (to preserve pointer equality).
+</p>
-<p>The <tt>User</tt> class is the common base class of all LLVM nodes that may
-refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
-that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
-referring to. The <tt>User</tt> class itself is a subclass of
-<tt>Value</tt>.</p>
+<p>
+In the example above, the OpaqueType object is definitely deleted.
+Additionally, if there is an "{ \2*, int}" type already created in the system,
+the pointer and struct type created are <b>also</b> deleted. Obviously whenever
+a type is deleted, any "Type*" pointers in the program are invalidated. As
+such, it is safest to avoid having <i>any</i> "Type*" pointers to abstract types
+live across a call to <tt>refineAbstractTypeTo</tt> (note that non-abstract
+types can never move or be deleted). To deal with this, the <a
+href="#PATypeHolder">PATypeHolder</a> class is used to maintain a stable
+reference to a possibly refined type, and the <a
+href="#AbstractTypeUser">AbstractTypeUser</a> class is used to update more
+complex datastructures.
+</p>
+
+</div>
+
+<!-- ______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="PATypeHolder">The PATypeHolder Class</a>
+</div>
-<p>The operands of a <tt>User</tt> point directly to the LLVM <a
-href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
-Single Assignment (SSA) form, there can only be one definition referred to,
-allowing this direct connection. This connection provides the use-def
-information in LLVM.</p>
+<div class="doc_text">
+<p>
+PATypeHolder is a form of a "smart pointer" for Type objects. When VMCore
+happily goes about nuking types that become isomorphic to existing types, it
+automatically updates all PATypeHolder objects to point to the new type. In the
+example above, this allows the code to maintain a pointer to the resultant
+resolved recursive type, even though the Type*'s are potentially invalidated.
+</p>
+
+<p>
+PATypeHolder is an extremely light-weight object that uses a lazy union-find
+implementation to update pointers. For example the pointer from a Value to its
+Type is maintained by PATypeHolder objects.
+</p>
</div>
-<!-- _______________________________________________________________________ -->
+<!-- ______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="m_User">Important Public Members of the <tt>User</tt> class</a>
+ <a name="AbstractTypeUser">The AbstractTypeUser Class</a>
</div>
<div class="doc_text">
-<p>The <tt>User</tt> class exposes the operand list in two ways: through
-an index access interface and through an iterator based interface.</p>
-
-<ul>
- <li><tt>Value *getOperand(unsigned i)</tt><br>
- <tt>unsigned getNumOperands()</tt>
- <p> These two methods expose the operands of the <tt>User</tt> in a
-convenient form for direct access.</p></li>
+<p>
+Some data structures need more to perform more complex updates when types get
+resolved. The <a href="#SymbolTable">SymbolTable</a> class, for example, needs
+move and potentially merge type planes in its representation when a pointer
+changes.</p>
- <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand
-list<br>
- <tt>User::op_const_iterator</tt> <tt>use_iterator op_begin()</tt> -
-Get an iterator to the start of the operand list.<br>
- <tt>use_iterator op_end()</tt> - Get an iterator to the end of the
-operand list.
- <p> Together, these methods make up the iterator based interface to
-the operands of a <tt>User</tt>.</p></li>
-</ul>
+<p>
+To support this, a class can derive from the AbstractTypeUser class. This class
+allows it to get callbacks when certain types are resolved. To register to get
+callbacks for a particular type, the DerivedType::{add/remove}AbstractTypeUser
+methods can be called on a type. Note that these methods only work for <i>
+abstract</i> types. Concrete types (those that do not include an opaque objects
+somewhere) can never be refined.
+</p>
+</div>
-</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="Instruction">The <tt>Instruction</tt> class</a>
+ <a name="SymbolTable">The <tt>SymbolTable</tt> class</a>
</div>
<div class="doc_text">
+<p>This class provides a symbol table that the <a
+href="#Function"><tt>Function</tt></a> and <a href="#Module">
+<tt>Module</tt></a> classes use for naming definitions. The symbol table can
+provide a name for any <a href="#Value"><tt>Value</tt></a> or <a
+href="#Type"><tt>Type</tt></a>. <tt>SymbolTable</tt> is an abstract data
+type. It hides the data it contains and provides access to it through a
+controlled interface.</p>
-<p><tt>#include "</tt><tt><a
-href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt><br>
-doxygen info: <a href="/doxygen/classllvm_1_1Instruction.html">Instruction Class</a><br>
-Superclasses: <a href="#User"><tt>User</tt></a>, <a
-href="#Value"><tt>Value</tt></a></p>
+<p>Note that the symbol table class is should not be directly accessed by most
+clients. It should only be used when iteration over the symbol table names
+themselves are required, which is very special purpose. Note that not all LLVM
+<a href="#Value">Value</a>s have names, and those without names (i.e. they have
+an empty name) do not exist in the symbol table.
+</p>
-<p>The <tt>Instruction</tt> class is the common base class for all LLVM
-instructions. It provides only a few methods, but is a very commonly used
-class. The primary data tracked by the <tt>Instruction</tt> class itself is the
-opcode (instruction type) and the parent <a
-href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
-into. To represent a specific type of instruction, one of many subclasses of
-<tt>Instruction</tt> are used.</p>
+<p>To use the <tt>SymbolTable</tt> well, you need to understand the
+structure of the information it holds. The class contains two
+<tt>std::map</tt> objects. The first, <tt>pmap</tt>, is a map of
+<tt>Type*</tt> to maps of name (<tt>std::string</tt>) to <tt>Value*</tt>.
+The second, <tt>tmap</tt>, is a map of names to <tt>Type*</tt>. Thus, Values
+are stored in two-dimensions and accessed by <tt>Type</tt> and name. Types,
+however, are stored in a single dimension and accessed only by name.</p>
-<p> Because the <tt>Instruction</tt> class subclasses the <a
-href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
-way as for other <a href="#User"><tt>User</tt></a>s (with the
-<tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
-<tt>op_begin()</tt>/<tt>op_end()</tt> methods).</p> <p> An important file for
-the <tt>Instruction</tt> class is the <tt>llvm/Instruction.def</tt> file. This
-file contains some meta-data about the various different types of instructions
-in LLVM. It describes the enum values that are used as opcodes (for example
-<tt>Instruction::Add</tt> and <tt>Instruction::SetLE</tt>), as well as the
-concrete sub-classes of <tt>Instruction</tt> that implement the instruction (for
-example <tt><a href="#BinaryOperator">BinaryOperator</a></tt> and <tt><a
-href="#SetCondInst">SetCondInst</a></tt>). Unfortunately, the use of macros in
-this file confuses doxygen, so these enum values don't show up correctly in the
+<p>The interface of this class provides three basic types of operations:
+<ol>
+ <li><em>Accessors</em>. Accessors provide read-only access to information
+ such as finding a value for a name with the
+ <a href="#SymbolTable_lookup">lookup</a> method.</li>
+ <li><em>Mutators</em>. Mutators allow the user to add information to the
+ <tt>SymbolTable</tt> with methods like
+ <a href="#SymbolTable_insert"><tt>insert</tt></a>.</li>
+ <li><em>Iterators</em>. Iterators allow the user to traverse the content
+ of the symbol table in well defined ways, such as the method
+ <a href="#SymbolTable_type_begin"><tt>type_begin</tt></a>.</li>
+</ol>
+
+<h3>Accessors</h3>
+<dl>
+ <dt><tt>Value* lookup(const Type* Ty, const std::string& name) const</tt>:
+ </dt>
+ <dd>The <tt>lookup</tt> method searches the type plane given by the
+ <tt>Ty</tt> parameter for a <tt>Value</tt> with the provided <tt>name</tt>.
+ If a suitable <tt>Value</tt> is not found, null is returned.</dd>
+
+ <dt><tt>Type* lookupType( const std::string& name) const</tt>:</dt>
+ <dd>The <tt>lookupType</tt> method searches through the types for a
+ <tt>Type</tt> with the provided <tt>name</tt>. If a suitable <tt>Type</tt>
+ is not found, null is returned.</dd>
+
+ <dt><tt>bool hasTypes() const</tt>:</dt>
+ <dd>This function returns true if an entry has been made into the type
+ map.</dd>
+
+ <dt><tt>bool isEmpty() const</tt>:</dt>
+ <dd>This function returns true if both the value and types maps are
+ empty</dd>
+</dl>
+
+<h3>Mutators</h3>
+<dl>
+ <dt><tt>void insert(Value *Val)</tt>:</dt>
+ <dd>This method adds the provided value to the symbol table. The Value must
+ have both a name and a type which are extracted and used to place the value
+ in the correct type plane under the value's name.</dd>
+
+ <dt><tt>void insert(const std::string& Name, Value *Val)</tt>:</dt>
+ <dd> Inserts a constant or type into the symbol table with the specified
+ name. There can be a many to one mapping between names and constants
+ or types.</dd>
+
+ <dt><tt>void insert(const std::string& Name, Type *Typ)</tt>:</dt>
+ <dd> Inserts a type into the symbol table with the specified name. There
+ can be a many-to-one mapping between names and types. This method
+ allows a type with an existing entry in the symbol table to get
+ a new name.</dd>
+
+ <dt><tt>void remove(Value* Val)</tt>:</dt>
+ <dd> This method removes a named value from the symbol table. The
+ type and name of the Value are extracted from \p N and used to
+ lookup the Value in the correct type plane. If the Value is
+ not in the symbol table, this method silently ignores the
+ request.</dd>
+
+ <dt><tt>void remove(Type* Typ)</tt>:</dt>
+ <dd> This method removes a named type from the symbol table. The
+ name of the type is extracted from \P T and used to look up
+ the Type in the type map. If the Type is not in the symbol
+ table, this method silently ignores the request.</dd>
+
+ <dt><tt>Value* remove(const std::string& Name, Value *Val)</tt>:</dt>
+ <dd> Remove a constant or type with the specified name from the
+ symbol table.</dd>
+
+ <dt><tt>Type* remove(const std::string& Name, Type* T)</tt>:</dt>
+ <dd> Remove a type with the specified name from the symbol table.
+ Returns the removed Type.</dd>
+
+ <dt><tt>Value *value_remove(const value_iterator& It)</tt>:</dt>
+ <dd> Removes a specific value from the symbol table.
+ Returns the removed value.</dd>
+
+ <dt><tt>bool strip()</tt>:</dt>
+ <dd> This method will strip the symbol table of its names leaving
+ the type and values. </dd>
+
+ <dt><tt>void clear()</tt>:</dt>
+ <dd>Empty the symbol table completely.</dd>
+</dl>
+
+<h3>Iteration</h3>
+<p>The following functions describe three types of iterators you can obtain
+the beginning or end of the sequence for both const and non-const. It is
+important to keep track of the different kinds of iterators. There are
+three idioms worth pointing out:</p>
+
+<table>
+ <tr><th>Units</th><th>Iterator</th><th>Idiom</th></tr>
+ <tr>
+ <td align="left">Planes Of name/Value maps</td><td>PI</td>
+ <td align="left"><pre><tt>
+for (SymbolTable::plane_const_iterator PI = ST.plane_begin(),
+ PE = ST.plane_end(); PI != PE; ++PI ) {
+ PI->first // <i>This is the Type* of the plane</i>
+ PI->second // <i>This is the SymbolTable::ValueMap of name/Value pairs</i>
+}
+ </tt></pre></td>
+ </tr>
+ <tr>
+ <td align="left">All name/Type Pairs</td><td>TI</td>
+ <td align="left"><pre><tt>
+for (SymbolTable::type_const_iterator TI = ST.type_begin(),
+ TE = ST.type_end(); TI != TE; ++TI ) {
+ TI->first // <i>This is the name of the type</i>
+ TI->second // <i>This is the Type* value associated with the name</i>
+}
+ </tt></pre></td>
+ </tr>
+ <tr>
+ <td align="left">name/Value pairs in a plane</td><td>VI</td>
+ <td align="left"><pre><tt>
+for (SymbolTable::value_const_iterator VI = ST.value_begin(SomeType),
+ VE = ST.value_end(SomeType); VI != VE; ++VI ) {
+ VI->first // <i>This is the name of the Value</i>
+ VI->second // <i>This is the Value* value associated with the name</i>
+}
+ </tt></pre></td>
+ </tr>
+</table>
+
+<p>Using the recommended iterator names and idioms will help you avoid
+making mistakes. Of particular note, make sure that whenever you use
+value_begin(SomeType) that you always compare the resulting iterator
+with value_end(SomeType) not value_end(SomeOtherType) or else you
+will loop infinitely.</p>
+
+<dl>
+
+ <dt><tt>plane_iterator plane_begin()</tt>:</dt>
+ <dd>Get an iterator that starts at the beginning of the type planes.
+ The iterator will iterate over the Type/ValueMap pairs in the
+ type planes. </dd>
+
+ <dt><tt>plane_const_iterator plane_begin() const</tt>:</dt>
+ <dd>Get a const_iterator that starts at the beginning of the type
+ planes. The iterator will iterate over the Type/ValueMap pairs
+ in the type planes. </dd>
+
+ <dt><tt>plane_iterator plane_end()</tt>:</dt>
+ <dd>Get an iterator at the end of the type planes. This serves as
+ the marker for end of iteration over the type planes.</dd>
+
+ <dt><tt>plane_const_iterator plane_end() const</tt>:</dt>
+ <dd>Get a const_iterator at the end of the type planes. This serves as
+ the marker for end of iteration over the type planes.</dd>
+
+ <dt><tt>value_iterator value_begin(const Type *Typ)</tt>:</dt>
+ <dd>Get an iterator that starts at the beginning of a type plane.
+ The iterator will iterate over the name/value pairs in the type plane.
+ Note: The type plane must already exist before using this.</dd>
+
+ <dt><tt>value_const_iterator value_begin(const Type *Typ) const</tt>:</dt>
+ <dd>Get a const_iterator that starts at the beginning of a type plane.
+ The iterator will iterate over the name/value pairs in the type plane.
+ Note: The type plane must already exist before using this.</dd>
+
+ <dt><tt>value_iterator value_end(const Type *Typ)</tt>:</dt>
+ <dd>Get an iterator to the end of a type plane. This serves as the marker
+ for end of iteration of the type plane.
+ Note: The type plane must already exist before using this.</dd>
+
+ <dt><tt>value_const_iterator value_end(const Type *Typ) const</tt>:</dt>
+ <dd>Get a const_iterator to the end of a type plane. This serves as the
+ marker for end of iteration of the type plane.
+ Note: the type plane must already exist before using this.</dd>
+
+ <dt><tt>type_iterator type_begin()</tt>:</dt>
+ <dd>Get an iterator to the start of the name/Type map.</dd>
+
+ <dt><tt>type_const_iterator type_begin() cons</tt>:</dt>
+ <dd> Get a const_iterator to the start of the name/Type map.</dd>
+
+ <dt><tt>type_iterator type_end()</tt>:</dt>
+ <dd>Get an iterator to the end of the name/Type map. This serves as the
+ marker for end of iteration of the types.</dd>
+
+ <dt><tt>type_const_iterator type_end() const</tt>:</dt>
+ <dd>Get a const-iterator to the end of the name/Type map. This serves
+ as the marker for end of iteration of the types.</dd>
+
+ <dt><tt>plane_const_iterator find(const Type* Typ ) const</tt>:</dt>
+ <dd>This method returns a plane_const_iterator for iteration over
+ the type planes starting at a specific plane, given by \p Ty.</dd>
+
+ <dt><tt>plane_iterator find( const Type* Typ </tt>:</dt>
+ <dd>This method returns a plane_iterator for iteration over the
+ type planes starting at a specific plane, given by \p Ty.</dd>
+
+</dl>
+</div>
+
+
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="coreclasses">The Core LLVM Class Hierarchy Reference </a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+
+<p>The Core LLVM classes are the primary means of representing the program
+being inspected or transformed. The core LLVM classes are defined in
+header files in the <tt>include/llvm/</tt> directory, and implemented in
+the <tt>lib/VMCore</tt> directory.</p>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="Value">The <tt>Value</tt> class</a>
+</div>
+
+<div>
+
+<p><tt>#include "<a href="/doxygen/Value_8h-source.html">llvm/Value.h</a>"</tt>
+<br>
+doxygen info: <a href="/doxygen/structllvm_1_1Value.html">Value Class</a></p>
+
+<p>The <tt>Value</tt> class is the most important class in the LLVM Source
+base. It represents a typed value that may be used (among other things) as an
+operand to an instruction. There are many different types of <tt>Value</tt>s,
+such as <a href="#Constant"><tt>Constant</tt></a>s,<a
+href="#Argument"><tt>Argument</tt></a>s. Even <a
+href="#Instruction"><tt>Instruction</tt></a>s and <a
+href="#Function"><tt>Function</tt></a>s are <tt>Value</tt>s.</p>
+
+<p>A particular <tt>Value</tt> may be used many times in the LLVM representation
+for a program. For example, an incoming argument to a function (represented
+with an instance of the <a href="#Argument">Argument</a> class) is "used" by
+every instruction in the function that references the argument. To keep track
+of this relationship, the <tt>Value</tt> class keeps a list of all of the <a
+href="#User"><tt>User</tt></a>s that is using it (the <a
+href="#User"><tt>User</tt></a> class is a base class for all nodes in the LLVM
+graph that can refer to <tt>Value</tt>s). This use list is how LLVM represents
+def-use information in the program, and is accessible through the <tt>use_</tt>*
+methods, shown below.</p>
+
+<p>Because LLVM is a typed representation, every LLVM <tt>Value</tt> is typed,
+and this <a href="#Type">Type</a> is available through the <tt>getType()</tt>
+method. In addition, all LLVM values can be named. The "name" of the
+<tt>Value</tt> is a symbolic string printed in the LLVM code:</p>
+
+<div class="doc_code">
+<pre>
+%<b>foo</b> = add int 1, 2
+</pre>
+</div>
+
+<p><a name="#nameWarning">The name of this instruction is "foo".</a> <b>NOTE</b>
+that the name of any value may be missing (an empty string), so names should
+<b>ONLY</b> be used for debugging (making the source code easier to read,
+debugging printouts), they should not be used to keep track of values or map
+between them. For this purpose, use a <tt>std::map</tt> of pointers to the
+<tt>Value</tt> itself instead.</p>
+
+<p>One important aspect of LLVM is that there is no distinction between an SSA
+variable and the operation that produces it. Because of this, any reference to
+the value produced by an instruction (or the value available as an incoming
+argument, for example) is represented as a direct pointer to the instance of
+the class that
+represents this value. Although this may take some getting used to, it
+simplifies the representation and makes it easier to manipulate.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_Value">Important Public Members of the <tt>Value</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+ <li><tt>Value::use_iterator</tt> - Typedef for iterator over the
+use-list<br>
+ <tt>Value::use_const_iterator</tt> - Typedef for const_iterator over
+the use-list<br>
+ <tt>unsigned use_size()</tt> - Returns the number of users of the
+value.<br>
+ <tt>bool use_empty()</tt> - Returns true if there are no users.<br>
+ <tt>use_iterator use_begin()</tt> - Get an iterator to the start of
+the use-list.<br>
+ <tt>use_iterator use_end()</tt> - Get an iterator to the end of the
+use-list.<br>
+ <tt><a href="#User">User</a> *use_back()</tt> - Returns the last
+element in the list.
+ <p> 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>
+ </li>
+ <li><tt><a href="#Type">Type</a> *getType() const</tt>
+ <p>This method returns the Type of the Value.</p>
+ </li>
+ <li><tt>bool hasName() const</tt><br>
+ <tt>std::string getName() const</tt><br>
+ <tt>void setName(const std::string &Name)</tt>
+ <p> This family of methods is used to access and assign a name to a <tt>Value</tt>,
+be aware of the <a href="#nameWarning">precaution above</a>.</p>
+ </li>
+ <li><tt>void replaceAllUsesWith(Value *V)</tt>
+
+ <p>This method traverses the use list of a <tt>Value</tt> changing all <a
+ href="#User"><tt>User</tt>s</a> of the current value to refer to
+ "<tt>V</tt>" instead. For example, if you detect that an instruction always
+ produces a constant value (for example through constant folding), you can
+ replace all uses of the instruction with the constant like this:</p>
+
+<div class="doc_code">
+<pre>
+Inst->replaceAllUsesWith(ConstVal);
+</pre>
+</div>
+
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="User">The <tt>User</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p>
+<tt>#include "<a href="/doxygen/User_8h-source.html">llvm/User.h</a>"</tt><br>
+doxygen info: <a href="/doxygen/classllvm_1_1User.html">User Class</a><br>
+Superclass: <a href="#Value"><tt>Value</tt></a></p>
+
+<p>The <tt>User</tt> class is the common base class of all LLVM nodes that may
+refer to <a href="#Value"><tt>Value</tt></a>s. It exposes a list of "Operands"
+that are all of the <a href="#Value"><tt>Value</tt></a>s that the User is
+referring to. The <tt>User</tt> class itself is a subclass of
+<tt>Value</tt>.</p>
+
+<p>The operands of a <tt>User</tt> point directly to the LLVM <a
+href="#Value"><tt>Value</tt></a> that it refers to. Because LLVM uses Static
+Single Assignment (SSA) form, there can only be one definition referred to,
+allowing this direct connection. This connection provides the use-def
+information in LLVM.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_User">Important Public Members of the <tt>User</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p>The <tt>User</tt> class exposes the operand list in two ways: through
+an index access interface and through an iterator based interface.</p>
+
+<ul>
+ <li><tt>Value *getOperand(unsigned i)</tt><br>
+ <tt>unsigned getNumOperands()</tt>
+ <p> These two methods expose the operands of the <tt>User</tt> in a
+convenient form for direct access.</p></li>
+
+ <li><tt>User::op_iterator</tt> - Typedef for iterator over the operand
+list<br>
+ <tt>op_iterator op_begin()</tt> - Get an iterator to the start of
+the operand list.<br>
+ <tt>op_iterator op_end()</tt> - Get an iterator to the end of the
+operand list.
+ <p> Together, these methods make up the iterator based interface to
+the operands of a <tt>User</tt>.</p></li>
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="Instruction">The <tt>Instruction</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p><tt>#include "</tt><tt><a
+href="/doxygen/Instruction_8h-source.html">llvm/Instruction.h</a>"</tt><br>
+doxygen info: <a href="/doxygen/classllvm_1_1Instruction.html">Instruction Class</a><br>
+Superclasses: <a href="#User"><tt>User</tt></a>, <a
+href="#Value"><tt>Value</tt></a></p>
+
+<p>The <tt>Instruction</tt> class is the common base class for all LLVM
+instructions. It provides only a few methods, but is a very commonly used
+class. The primary data tracked by the <tt>Instruction</tt> class itself is the
+opcode (instruction type) and the parent <a
+href="#BasicBlock"><tt>BasicBlock</tt></a> the <tt>Instruction</tt> is embedded
+into. To represent a specific type of instruction, one of many subclasses of
+<tt>Instruction</tt> are used.</p>
+
+<p> Because the <tt>Instruction</tt> class subclasses the <a
+href="#User"><tt>User</tt></a> class, its operands can be accessed in the same
+way as for other <a href="#User"><tt>User</tt></a>s (with the
+<tt>getOperand()</tt>/<tt>getNumOperands()</tt> and
+<tt>op_begin()</tt>/<tt>op_end()</tt> methods).</p> <p> An important file for
+the <tt>Instruction</tt> class is the <tt>llvm/Instruction.def</tt> file. This
+file contains some meta-data about the various different types of instructions
+in LLVM. It describes the enum values that are used as opcodes (for example
+<tt>Instruction::Add</tt> and <tt>Instruction::SetLE</tt>), as well as the
+concrete sub-classes of <tt>Instruction</tt> that implement the instruction (for
+example <tt><a href="#BinaryOperator">BinaryOperator</a></tt> and <tt><a
+href="#SetCondInst">SetCondInst</a></tt>). Unfortunately, the use of macros in
+this file confuses doxygen, so these enum values don't show up correctly in the
<a href="/doxygen/classllvm_1_1Instruction.html">doxygen output</a>.</p>
</div>
<div class="doc_text">
<ul>
- <li><tt>BasicBlock(const std::string &Name = "", </tt><tt><a
+
+<li><tt>BasicBlock(const std::string &Name = "", </tt><tt><a
href="#Function">Function</a> *Parent = 0)</tt>
- <p>The <tt>BasicBlock</tt> constructor is used to create new basic
-blocks for insertion into a function. The constructor optionally takes
-a name for the new block, and a <a href="#Function"><tt>Function</tt></a>
-to insert it into. If the <tt>Parent</tt> parameter is specified, the
-new <tt>BasicBlock</tt> is automatically inserted at the end of the
-specified <a href="#Function"><tt>Function</tt></a>, if not specified,
-the BasicBlock must be manually inserted into the <a href="#Function"><tt>Function</tt></a>.</p>
- </li>
- <li><tt>BasicBlock::iterator</tt> - Typedef for instruction list
-iterator<br>
- <tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
- <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,<tt>size()</tt>,<tt>empty()</tt>,<tt>rbegin()</tt>,<tt>rend()
-- </tt>STL style functions for accessing the instruction list.
- <p> These methods and typedefs are forwarding functions that have
-the same semantics as the standard library methods of the same names.
-These methods expose the underlying instruction list of a basic block in
-a way that is easy to manipulate. To get the full complement of
-container operations (including operations to update the list), you must
-use the <tt>getInstList()</tt> method.</p></li>
- <li><tt>BasicBlock::InstListType &getInstList()</tt>
- <p> This method is used to get access to the underlying container
-that actually holds the Instructions. This method must be used when
-there isn't a forwarding function in the <tt>BasicBlock</tt> class for
-the operation that you would like to perform. Because there are no
-forwarding functions for "updating" operations, you need to use this if
-you want to update the contents of a <tt>BasicBlock</tt>.</p></li>
- <li><tt><a href="#Function">Function</a> *getParent()</tt>
- <p> Returns a pointer to <a href="#Function"><tt>Function</tt></a>
-the block is embedded into, or a null pointer if it is homeless.</p></li>
- <li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt>
- <p> Returns a pointer to the terminator instruction that appears at
-the end of the <tt>BasicBlock</tt>. If there is no terminator
-instruction, or if the last instruction in the block is not a
-terminator, then a null pointer is returned.</p></li>
+
+<p>The <tt>BasicBlock</tt> constructor is used to create new basic blocks for
+insertion into a function. The constructor optionally takes a name for the new
+block, and a <a href="#Function"><tt>Function</tt></a> to insert it into. If
+the <tt>Parent</tt> parameter is specified, the new <tt>BasicBlock</tt> is
+automatically inserted at the end of the specified <a
+href="#Function"><tt>Function</tt></a>, if not specified, the BasicBlock must be
+manually inserted into the <a href="#Function"><tt>Function</tt></a>.</p></li>
+
+<li><tt>BasicBlock::iterator</tt> - Typedef for instruction list iterator<br>
+<tt>BasicBlock::const_iterator</tt> - Typedef for const_iterator.<br>
+<tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
+<tt>size()</tt>, <tt>empty()</tt>
+STL-style functions for accessing the instruction list.
+
+<p>These methods and typedefs are forwarding functions that have the same
+semantics as the standard library methods of the same names. These methods
+expose the underlying instruction list of a basic block in a way that is easy to
+manipulate. To get the full complement of container operations (including
+operations to update the list), you must use the <tt>getInstList()</tt>
+method.</p></li>
+
+<li><tt>BasicBlock::InstListType &getInstList()</tt>
+
+<p>This method is used to get access to the underlying container that actually
+holds the Instructions. This method must be used when there isn't a forwarding
+function in the <tt>BasicBlock</tt> class for the operation that you would like
+to perform. Because there are no forwarding functions for "updating"
+operations, you need to use this if you want to update the contents of a
+<tt>BasicBlock</tt>.</p></li>
+
+<li><tt><a href="#Function">Function</a> *getParent()</tt>
+
+<p> Returns a pointer to <a href="#Function"><tt>Function</tt></a> the block is
+embedded into, or a null pointer if it is homeless.</p></li>
+
+<li><tt><a href="#TerminatorInst">TerminatorInst</a> *getTerminator()</tt>
+
+<p> Returns a pointer to the terminator instruction that appears at the end of
+the <tt>BasicBlock</tt>. If there is no terminator instruction, or if the last
+instruction in the block is not a terminator, then a null pointer is
+returned.</p></li>
+
</ul>
</div>
<p><tt>#include "<a
href="/doxygen/GlobalValue_8h-source.html">llvm/GlobalValue.h</a>"</tt><br>
doxygen info: <a href="/doxygen/classllvm_1_1GlobalValue.html">GlobalValue
-Class</a><br>
-Superclasses: <a href="#User"><tt>User</tt></a>, <a
-href="#Value"><tt>Value</tt></a></p>
+Class</a><br>
+Superclasses: <a href="#Constant"><tt>Constant</tt></a>,
+<a href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a></p>
<p>Global values (<a href="#GlobalVariable"><tt>GlobalVariable</tt></a>s or <a
href="#Function"><tt>Function</tt></a>s) are the only LLVM values that are
<p><tt>#include "<a
href="/doxygen/Function_8h-source.html">llvm/Function.h</a>"</tt><br> doxygen
info: <a href="/doxygen/classllvm_1_1Function.html">Function Class</a><br>
-Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
-href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a></p>
+Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>,
+<a href="#Constant"><tt>Constant</tt></a>,
+<a href="#User"><tt>User</tt></a>,
+<a href="#Value"><tt>Value</tt></a></p>
<p>The <tt>Function</tt> class represents a single procedure in LLVM. It is
actually one of the more complex classes in the LLVM heirarchy because it must
keep track of a large amount of data. The <tt>Function</tt> class keeps track
-of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal <a
-href="#Argument"><tt>Argument</tt></a>s, and a <a
-href="#SymbolTable"><tt>SymbolTable</tt></a>.</p>
+of a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, a list of formal
+<a href="#Argument"><tt>Argument</tt></a>s, and a
+<a href="#SymbolTable"><tt>SymbolTable</tt></a>.</p>
<p>The list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s is the most
commonly used part of <tt>Function</tt> objects. The list imposes an implicit
<li><tt>Function::iterator</tt> - Typedef for basic block list iterator<br>
<tt>Function::const_iterator</tt> - Typedef for const_iterator.<br>
- <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
- <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt>
+ <tt>begin()</tt>, <tt>end()</tt>
+ <tt>size()</tt>, <tt>empty()</tt>
<p>These are forwarding methods that make it easy to access the contents of
a <tt>Function</tt> object's <a href="#BasicBlock"><tt>BasicBlock</tt></a>
is necessary to use when you need to update the list or perform a complex
action that doesn't have a forwarding method.</p></li>
- <li><tt>Function::aiterator</tt> - Typedef for the argument list
+ <li><tt>Function::arg_iterator</tt> - Typedef for the argument list
iterator<br>
- <tt>Function::const_aiterator</tt> - Typedef for const_iterator.<br>
+ <tt>Function::const_arg_iterator</tt> - Typedef for const_iterator.<br>
- <tt>abegin()</tt>, <tt>aend()</tt>, <tt>afront()</tt>, <tt>aback()</tt>,
- <tt>asize()</tt>, <tt>aempty()</tt>, <tt>arbegin()</tt>, <tt>arend()</tt>
+ <tt>arg_begin()</tt>, <tt>arg_end()</tt>
+ <tt>arg_size()</tt>, <tt>arg_empty()</tt>
<p>These are forwarding methods that make it easy to access the contents of
a <tt>Function</tt> object's <a href="#Argument"><tt>Argument</tt></a>
href="/doxygen/GlobalVariable_8h-source.html">llvm/GlobalVariable.h</a>"</tt>
<br>
doxygen info: <a href="/doxygen/classllvm_1_1GlobalVariable.html">GlobalVariable
-Class</a><br> Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>, <a
-href="#User"><tt>User</tt></a>, <a href="#Value"><tt>Value</tt></a></p>
+ Class</a><br>
+Superclasses: <a href="#GlobalValue"><tt>GlobalValue</tt></a>,
+<a href="#Constant"><tt>Constant</tt></a>,
+<a href="#User"><tt>User</tt></a>,
+<a href="#Value"><tt>Value</tt></a></p>
<p>Global variables are represented with the (suprise suprise)
<tt>GlobalVariable</tt> class. Like functions, <tt>GlobalVariable</tt>s are also
subclasses of <a href="#GlobalValue"><tt>GlobalValue</tt></a>, and as such are
always referenced by their address (global values must live in memory, so their
-"name" refers to their address). See <a
-href="#GlobalValue"><tt>GlobalValue</tt></a> for more on this. Global variables
-may have an initial value (which must be a <a
-href="#Constant"><tt>Constant</tt></a>), and if they have an initializer, they
-may be marked as "constant" themselves (indicating that their contents never
-change at runtime).</p>
-
+"name" refers to their constant address). See
+<a href="#GlobalValue"><tt>GlobalValue</tt></a> for more on this. Global
+variables may have an initial value (which must be a
+<a href="#Constant"><tt>Constant</tt></a>), and if they have an initializer,
+they may be marked as "constant" themselves (indicating that their contents
+never change at runtime).</p>
</div>
<!-- _______________________________________________________________________ -->
<li><tt>Module::iterator</tt> - Typedef for function list iterator<br>
<tt>Module::const_iterator</tt> - Typedef for const_iterator.<br>
- <tt>begin()</tt>, <tt>end()</tt>, <tt>front()</tt>, <tt>back()</tt>,
- <tt>size()</tt>, <tt>empty()</tt>, <tt>rbegin()</tt>, <tt>rend()</tt>
+ <tt>begin()</tt>, <tt>end()</tt>
+ <tt>size()</tt>, <tt>empty()</tt>
<p>These are forwarding methods that make it easy to access the contents of
a <tt>Module</tt> object's <a href="#Function"><tt>Function</tt></a>
<hr>
<ul>
- <li><tt>Module::giterator</tt> - Typedef for global variable list iterator<br>
+ <li><tt>Module::global_iterator</tt> - Typedef for global variable list iterator<br>
- <tt>Module::const_giterator</tt> - Typedef for const_iterator.<br>
+ <tt>Module::const_global_iterator</tt> - Typedef for const_iterator.<br>
- <tt>gbegin()</tt>, <tt>gend()</tt>, <tt>gfront()</tt>, <tt>gback()</tt>,
- <tt>gsize()</tt>, <tt>gempty()</tt>, <tt>grbegin()</tt>, <tt>grend()</tt>
+ <tt>global_begin()</tt>, <tt>global_end()</tt>
+ <tt>global_size()</tt>, <tt>global_empty()</tt>
<p> These are forwarding methods that make it easy to access the contents of
a <tt>Module</tt> object's <a
<div class="doc_text">
<p>Constant represents a base class for different types of constants. It
-is subclassed by ConstantBool, ConstantInt, ConstantSInt, ConstantUInt,
-ConstantArray etc for representing the various types of Constants.</p>
+is subclassed by ConstantBool, ConstantInt, ConstantArray etc for representing
+the various types of Constants.</p>
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
- <a name="m_Value">Important Public Methods</a>
+ <a name="m_Constant">Important Public Methods</a>
</div>
-
<div class="doc_text">
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">Important Subclasses of Constant </div>
+<div class="doc_text">
<ul>
- <hr> Important Subclasses of Constant
- <p> </p>
+ <li>ConstantInt : This subclass of Constant represents an integer constant.
<ul>
- <li>ConstantSInt : This subclass of Constant represents a signed
-integer constant.
- <ul>
- <li><tt>int64_t getValue() const</tt>: Returns the underlying value of
-this constant. </li>
- </ul>
- </li>
- <li>ConstantUInt : This class represents an unsigned integer.
- <ul>
- <li><tt>uint64_t getValue() const</tt>: Returns the underlying value
-of this constant. </li>
- </ul>
- </li>
- <li>ConstantFP : This class represents a floating point constant.
- <ul>
- <li><tt>double getValue() const</tt>: Returns the underlying value of
-this constant. </li>
- </ul>
- </li>
- <li>ConstantBool : This represents a boolean constant.
- <ul>
- <li><tt>bool getValue() const</tt>: Returns the underlying value of
-this constant. </li>
- </ul>
- </li>
- <li>ConstantArray : This represents a constant array.
- <ul>
- <li><tt>const std::vector<Use> &getValues() const</tt>:
-Returns a Vecotr of component constants that makeup this array. </li>
- </ul>
- </li>
- <li>ConstantStruct : This represents a constant struct.
- <ul>
- <li><tt>const std::vector<Use> &getValues() const</tt>:
-Returns a Vecotr of component constants that makeup this array. </li>
- </ul>
- </li>
- <li>GlobalValue : This represents either a global variable or a
- function. In either case, the value is a constant fixed address
- (after linking).
- </li>
+ <li><tt>int64_t getSExtValue() const</tt>: Returns the underlying value of
+ this constant as a sign extended signed integer value.</li>
+ <li><tt>uint64_t getZExtValue() const</tt>: Returns the underlying value
+ of this constant as a zero extended unsigned integer value.</li>
+ </ul>
+ </li>
+ <li>ConstantFP : This class represents a floating point constant.
+ <ul>
+ <li><tt>double getValue() const</tt>: Returns the underlying value of
+ this constant. </li>
+ </ul>
+ </li>
+ <li>ConstantBool : This represents a boolean constant.
+ <ul>
+ <li><tt>bool getValue() const</tt>: Returns the underlying value of this
+ constant. </li>
+ </ul>
+ </li>
+ <li>ConstantArray : This represents a constant array.
+ <ul>
+ <li><tt>const std::vector<Use> &getValues() const</tt>: Returns
+ a vector of component constants that makeup this array. </li>
</ul>
</li>
+ <li>ConstantStruct : This represents a constant struct.
+ <ul>
+ <li><tt>const std::vector<Use> &getValues() const</tt>: Returns
+ a vector of component constants that makeup this array. </li>
+ </ul>
+ </li>
+ <li>GlobalValue : This represents either a global variable or a function. In
+ either case, the value is a constant fixed address (after linking).
+ </li>
</ul>
</div>
<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 or one pointer type to another.</li>
+</ul>
+</div>
-<br>
- <p>Derived Types</p>
-
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_Value">Important Derived Types</a>
+</div>
+<div class="doc_text">
+<ul>
+ <li>SequentialType : This is subclassed by ArrayType and PointerType
<ul>
- <li>SequentialType : This is subclassed by ArrayType and PointerType
- <ul>
- <li><tt>const Type * getElementType() const</tt>: Returns the type of
-each of the elements in the sequential type. </li>
- </ul>
- </li>
- <li>ArrayType : This is a subclass of SequentialType and defines
-interface for array types.
- <ul>
- <li><tt>unsigned getNumElements() const</tt>: Returns the number of
-elements in the array. </li>
- </ul>
- </li>
- <li>PointerType : Subclass of SequentialType for pointer types. </li>
- <li>StructType : subclass of DerivedTypes for struct types </li>
- <li>FunctionType : subclass of DerivedTypes for function types.
- <ul>
- <li><tt>bool isVarArg() const</tt>: Returns true if its a vararg
- function</li>
- <li><tt> const Type * getReturnType() const</tt>: Returns the
- return type of the function.</li>
- <li><tt>const Type * getParamType (unsigned i)</tt>: Returns
- the type of the ith parameter.</li>
- <li><tt> const unsigned getNumParams() const</tt>: Returns the
- number of formal parameters.</li>
- </ul>
- </li>
+ <li><tt>const Type * getElementType() const</tt>: Returns the type of each
+ of the elements in the sequential type. </li>
+ </ul>
+ </li>
+ <li>ArrayType : This is a subclass of SequentialType and defines interface for
+ array types.
+ <ul>
+ <li><tt>unsigned getNumElements() const</tt>: Returns the number of
+ elements in the array. </li>
+ </ul>
+ </li>
+ <li>PointerType : Subclass of SequentialType for pointer types. </li>
+ <li>StructType : subclass of DerivedTypes for struct types </li>
+ <li>FunctionType : subclass of DerivedTypes for function types.
+ <ul>
+ <li><tt>bool isVarArg() const</tt>: Returns true if its a vararg
+ function</li>
+ <li><tt> const Type * getReturnType() const</tt>: Returns the
+ return type of the function.</li>
+ <li><tt>const Type * getParamType (unsigned i)</tt>: Returns
+ the type of the ith parameter.</li>
+ <li><tt> const unsigned getNumParams() const</tt>: Returns the
+ number of formal parameters.</li>
</ul>
</li>
</ul>
-
</div>
<!-- ======================================================================= -->
<div class="doc_text">
<p>This subclass of Value defines the interface for incoming formal
-arguments to a function. A Function maitanis a list of its formal
+arguments to a function. A Function maintains a list of its formal
arguments. An argument has a pointer to the parent Function.</p>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="SymbolTable">The <tt>SymbolTable</tt> class</a>
-</div>
-<div class="doc_text">
-<p>This class provides a symbol table that the
-<a href="#Function"><tt>Function</tt></a> and <a href="#Module">
-<tt>Module</tt></a> classes use for naming definitions. The symbol table can
-provide a name for any <a href="#Value"><tt>Value</tt></a> or
-<a href="#Type"><tt>Type</tt></a>. <tt>SymbolTable</tt> is an abstract data
-type. It hides the data it contains and provides access to it through a
-controlled interface.</p>
-
-<p>To use the <tt>SymbolTable</tt> well, you need to understand the
-structure of the information it holds. The class contains two
-<tt>std::map</tt> objects. The first, <tt>pmap</tt>, is a map of
-<tt>Type*</tt> to maps of name (<tt>std::string</tt>) to <tt>Value*</tt>.
-The second, <tt>tmap</tt>, is a map of names to <tt>Type*</tt>. Thus, Values
-are stored in two-dimensions and accessed by <tt>Type</tt> and name. Types,
-however, are stored in a single dimension and accessed only by name.</p>
-
-<p>The interface of this class provides three basic types of operations:
-<ol>
- <li><em>Accessors</em>. Accessors provide read-only access to information
- such as finding a value for a name with the
- <a href="#SymbolTable_lookup">lookup</a> method.</li>
- <li><em>Mutators</em>. Mutators allow the user to add information to the
- <tt>SymbolTable</tt> with methods like
- <a href="#SymbolTable_insert"><tt>insert</tt></a>.</li>
- <li><em>Iterators</em>. Iterators allow the user to traverse the content
- of the symbol table in well defined ways, such as the method
- <a href="#SymbolTable_type_begin"><tt>type_begin</tt></a>.</li>
-</ol>
-
-<h3>Accessors</h3>
-<dl>
- <dt><tt>Value* lookup(const Type* Ty, const std::string& name) const</tt>:
- </dt>
- <dd>The <tt>lookup</tt> method searches the type plane given by the
- <tt>Ty</tt> parameter for a <tt>Value</tt> with the provided <tt>name</tt>.
- If a suitable <tt>Value</tt> is not found, null is returned.</dd>
-
- <dt><tt>Type* lookupType( const std::string& name) const</tt>:</dt>
- <dd>The <tt>lookupType</tt> method searches through the types for a
- <tt>Type</tt> with the provided <tt>name</tt>. If a suitable <tt>Type</tt>
- is not found, null is returned.</dd>
-
- <dt><tt>bool hasTypes() const</tt>:</dt>
- <dd>This function returns true if an entry has been made into the type
- map.</dd>
-
- <dt><tt>bool isEmpty() const</tt>:</dt>
- <dd>This function returns true if both the value and types maps are
- empty</dd>
-
- <dt><tt>std::string get_name(const Value*) const</tt>:</dt>
- <dd>This function returns the name of the Value provided or the empty
- string if the Value is not in the symbol table.</dd>
-
- <dt><tt>std::string get_name(const Type*) const</tt>:</dt>
- <dd>This function returns the name of the Type provided or the empty
- string if the Type is not in the symbol table.</dd>
-</dl>
-
-<h3>Mutators</h3>
-<dl>
- <dt><tt>void insert(Value *Val)</tt>:</dt>
- <dd>This method adds the provided value to the symbol table. The Value must
- have both a name and a type which are extracted and used to place the value
- in the correct type plane under the value's name.</dd>
-
- <dt><tt>void insert(const std::string& Name, Value *Val)</tt>:</dt>
- <dd> Inserts a constant or type into the symbol table with the specified
- name. There can be a many to one mapping between names and constants
- or types.</dd>
-
- <dt><tt>void insert(const std::string& Name, Type *Typ)</tt>:</dt>
- <dd> Inserts a type into the symbol table with the specified name. There
- can be a many-to-one mapping between names and types. This method
- allows a type with an existing entry in the symbol table to get
- a new name.</dd>
-
- <dt><tt>void remove(Value* Val)</tt>:</dt>
- <dd> This method removes a named value from the symbol table. The
- type and name of the Value are extracted from \p N and used to
- lookup the Value in the correct type plane. If the Value is
- not in the symbol table, this method silently ignores the
- request.</dd>
-
- <dt><tt>void remove(Type* Typ)</tt>:</dt>
- <dd> This method removes a named type from the symbol table. The
- name of the type is extracted from \P T and used to look up
- the Type in the type map. If the Type is not in the symbol
- table, this method silently ignores the request.</dd>
-
- <dt><tt>Value* remove(const std::string& Name, Value *Val)</tt>:</dt>
- <dd> Remove a constant or type with the specified name from the
- symbol table.</dd>
-
- <dt><tt>Type* remove(const std::string& Name, Type* T)</tt>:</dt>
- <dd> Remove a type with the specified name from the symbol table.
- Returns the removed Type.</dd>
-
- <dt><tt>Value *value_remove(const value_iterator& It)</tt>:</dt>
- <dd> Removes a specific value from the symbol table.
- Returns the removed value.</dd>
-
- <dt><tt>bool strip()</tt>:</dt>
- <dd> This method will strip the symbol table of its names leaving
- the type and values. </dd>
-
- <dt><tt>void clear()</tt>:</dt>
- <dd>Empty the symbol table completely.</dd>
-</dl>
-
-<h3>Iteration</h3>
-<p>The following functions describe three types of iterators you can obtain
-the beginning or end of the sequence for both const and non-const. It is
-important to keep track of the different kinds of iterators. There are
-three idioms worth pointing out:</p>
-<table class="doc_table">
- <tr><th>Units</th><th>Iterator</th><th>Idiom</th></tr>
- <tr>
- <td>Planes Of name/Value maps</td><td>PI</td>
- <td><tt><pre>
-for (SymbolTable::plane_const_iterator PI = ST.plane_begin(),
-PE = ST.plane_end(); PI != PE; ++PI ) {
- PI->first // This is the Type* of the plane
- PI->second // This is the SymbolTable::ValueMap of name/Value pairs
- </pre></tt></td>
- </tr>
- <tr>
- <td>All name/Type Pairs</td><td>TI</td>
- <td><tt><pre>
-for (SymbolTable::type_const_iterator TI = ST.type_begin(),
- TE = ST.type_end(); TI != TE; ++TI )
- TI->first // This is the name of the type
- TI->second // This is the Type* value associated with the name
- </pre></tt></td>
- </tr>
- <tr>
- <td>name/Value pairs in a plane</td><td>VI</td>
- <td><tt><pre>
-for (SymbolTable::value_const_iterator VI = ST.value_begin(SomeType),
- VE = ST.value_end(SomeType); VI != VE; ++VI )
- VI->first // This is the name of the Value
- VI->second // This is the Value* value associated with the name
- </pre></tt></td>
- </tr>
-</table>
-<p>Using the recommended iterator names and idioms will help you avoid
-making mistakes. Of particular note, make sure that whenever you use
-value_begin(SomeType) that you always compare the resulting iterator
-with value_end(SomeType) not value_end(SomeOtherType) or else you
-will loop infinitely.</p>
-
-<dl>
-
- <dt><tt>plane_iterator plane_begin()</tt>:</dt>
- <dd>Get an iterator that starts at the beginning of the type planes.
- The iterator will iterate over the Type/ValueMap pairs in the
- type planes. </dd>
-
- <dt><tt>plane_const_iterator plane_begin() const</tt>:</dt>
- <dd>Get a const_iterator that starts at the beginning of the type
- planes. The iterator will iterate over the Type/ValueMap pairs
- in the type planes. </dd>
-
- <dt><tt>plane_iterator plane_end()</tt>:</dt>
- <dd>Get an iterator at the end of the type planes. This serves as
- the marker for end of iteration over the type planes.</dd>
-
- <dt><tt>plane_const_iterator plane_end() const</tt>:</dt>
- <dd>Get a const_iterator at the end of the type planes. This serves as
- the marker for end of iteration over the type planes.</dd>
-
- <dt><tt>value_iterator value_begin(const Type *Typ)</tt>:</dt>
- <dd>Get an iterator that starts at the beginning of a type plane.
- The iterator will iterate over the name/value pairs in the type plane.
- Note: The type plane must already exist before using this.</dd>
-
- <dt><tt>value_const_iterator value_begin(const Type *Typ) const</tt>:</dt>
- <dd>Get a const_iterator that starts at the beginning of a type plane.
- The iterator will iterate over the name/value pairs in the type plane.
- Note: The type plane must already exist before using this.</dd>
-
- <dt><tt>value_iterator value_end(const Type *Typ)</tt>:</dt>
- <dd>Get an iterator to the end of a type plane. This serves as the marker
- for end of iteration of the type plane.
- Note: The type plane must already exist before using this.</dd>
-
- <dt><tt>value_const_iterator value_end(const Type *Typ) const</tt>:</dt>
- <dd>Get a const_iterator to the end of a type plane. This serves as the
- marker for end of iteration of the type plane.
- Note: the type plane must already exist before using this.</dd>
-
- <dt><tt>type_iterator type_begin()</tt>:</dt>
- <dd>Get an iterator to the start of the name/Type map.</dd>
-
- <dt><tt>type_const_iterator type_begin() cons</tt>:</dt>
- <dd> Get a const_iterator to the start of the name/Type map.</dd>
-
- <dt><tt>type_iterator type_end()</tt>:</dt>
- <dd>Get an iterator to the end of the name/Type map. This serves as the
- marker for end of iteration of the types.</dd>
-
- <dt><tt>type_const_iterator type_end() const</tt>:</dt>
- <dd>Get a const-iterator to the end of the name/Type map. This serves
- as the marker for end of iteration of the types.</dd>
-
- <dt><tt>plane_const_iterator find(const Type* Typ ) const</tt>:</dt>
- <dd>This method returns a plane_const_iterator for iteration over
- the type planes starting at a specific plane, given by \p Ty.</dd>
-
- <dt><tt>plane_iterator find( const Type* Typ </tt>:</dt>
- <dd>This method returns a plane_iterator for iteration over the
- type planes starting at a specific plane, given by \p Ty.</dd>
-
- <dt><tt>const ValueMap* findPlane( const Type* Typ ) cons</tt>:</dt>
- <dd>This method returns a ValueMap* for a specific type plane. This
- interface is deprecated and may go away in the future.</dd>
-</dl>
-</div>
-
<!-- *********************************************************************** -->
<hr>
<address>
<a href="mailto:dhurjati@cs.uiuc.edu">Dinakar Dhurjati</a> and
<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
- <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
+ <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
</address>
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