+<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
+need to. Instead of dereferencing the iterator and then taking the address of
+the result, you can simply assign the iterator to the proper pointer type and
+you get the dereference and address-of operation as a result of the assignment
+(behind the scenes, this is a result of overloading casting mechanisms). Thus
+the last line of the last example,</p>
+
+<div class="doc_code">
+<pre>
+Instruction *pinst = &*i;
+</pre>
+</div>
+
+<p>is semantically equivalent to</p>
+
+<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
+snippet illustrates use of the conversion constructors provided by LLVM
+iterators. By using these, you can explicitly grab the iterator of something
+without actually obtaining it via iteration over some structure:</p>
+
+<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()) llvm::cerr << *it << "\n";
+}
+</pre>
+</div>
+
+</div>
+
+<!--_______________________________________________________________________-->
+<div class="doc_subsubsection">
+ <a name="iterate_complex">Finding call sites: a slightly more complex
+ example</a>
+</div>
+
+<div class="doc_text">
+
+<p>Say that you're writing a FunctionPass and would like to count all the
+locations in the entire module (that is, across every <tt>Function</tt>) where a
+certain function (i.e., some <tt>Function</tt>*) is already in scope. As you'll
+learn later, you may want to use an <tt>InstVisitor</tt> to accomplish this in a
+much more straight-forward manner, but this example will allow us to explore how
+you'd do it if you didn't have <tt>InstVisitor</tt> around. In pseudo-code, this
+is what we want to do:</p>
+
+<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, because we're writing a
+<tt>FunctionPass</tt>, our <tt>FunctionPass</tt>-derived class simply has to
+override the <tt>runOnFunction</tt> method):</p>
+
+<div class="doc_code">
+<pre>
+Function* targetFunc = ...;
+
+class OurFunctionPass : public FunctionPass {
+ public:
+ OurFunctionPass(): callCounter(0) { }
+
+ 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>
+
+<!--_______________________________________________________________________-->
+<div class="doc_subsubsection">
+ <a name="calls_and_invokes">Treating calls and invokes the same way</a>
+</div>
+
+<div class="doc_text">
+
+<p>You may have noticed that the previous example was a bit oversimplified in
+that it did not deal with call sites generated by 'invoke' instructions. In
+this, and in other situations, you may find that you want to treat
+<tt>CallInst</tt>s and <tt>InvokeInst</tt>s the same way, even though their
+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.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>
+
+<p>This class has "value semantics": it should be passed by value, not by
+reference and it should not be dynamically allocated or deallocated using
+<tt>operator new</tt> or <tt>operator delete</tt>. It is efficiently copyable,
+assignable and constructable, with costs equivalents to that of a bare pointer.
+If you look at its definition, it has only a single pointer member.</p>
+
+</div>
+
+<!--_______________________________________________________________________-->
+<div class="doc_subsubsection">
+ <a name="iterate_chains">Iterating over def-use & use-def chains</a>
+</div>
+
+<div class="doc_text">
+
+<p>Frequently, we might have an instance of the <a
+href="/doxygen/classllvm_1_1Value.html">Value Class</a> and we want to
+determine which <tt>User</tt>s use the <tt>Value</tt>. The list of all
+<tt>User</tt>s of a particular <tt>Value</tt> is called a <i>def-use</i> chain.
+For example, let's say we have a <tt>Function*</tt> named <tt>F</tt> to a
+particular function <tt>foo</tt>. Finding all of the instructions that
+<i>use</i> <tt>foo</tt> is as simple as iterating over the <i>def-use</i> chain
+of <tt>F</tt>:</p>
+
+<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)) {
+ llvm::cerr << "F is used in instruction:\n";
+ llvm::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
+<tt>Value</tt>s are used by it. The list of all <tt>Value</tt>s used by a
+<tt>User</tt> is known as a <i>use-def</i> chain. Instances of class
+<tt>Instruction</tt> are common <tt>User</tt>s, so we might want to iterate over
+all of the values that a particular instruction uses (that is, the operands of
+the particular <tt>Instruction</tt>):</p>
+
+<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
+ use-def chains ("finding all values used"): User::op_begin/op_end [op=operand]
+-->
+
+</div>
+
+<!--_______________________________________________________________________-->
+<div class="doc_subsubsection">
+ <a name="iterate_preds">Iterating over predecessors &
+successors of blocks</a>
+</div>
+
+<div class="doc_text">
+
+<p>Iterating over the predecessors and successors of a block is quite easy
+with the routines defined in <tt>"llvm/Support/CFG.h"</tt>. Just use code like
+this to iterate over all predecessors of BB:</p>
+
+<div class="doc_code">
+<pre>
+#include "llvm/Support/CFG.h"
+BasicBlock *BB = ...;
+
+for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
+ BasicBlock *Pred = *PI;
+ // <i>...</i>
+}
+</pre>
+</div>
+
+<p>Similarly, to iterate over successors use
+succ_iterator/succ_begin/succ_end.</p>
+
+</div>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="simplechanges">Making simple changes</a>
+</div>
+
+<div class="doc_text">
+
+<p>There are some primitive transformation operations present in the LLVM
+infrastructure that are worth knowing about. When performing
+transformations, it's fairly common to manipulate the contents of basic
+blocks. This section describes some of the common methods for doing so
+and gives example code.</p>
+
+</div>
+
+<!--_______________________________________________________________________-->
+<div class="doc_subsubsection">
+ <a name="schanges_creating">Creating and inserting new
+ <tt>Instruction</tt>s</a>
+</div>
+
+<div class="doc_text">
+
+<p><i>Instantiating Instructions</i></p>
+
+<p>Creation of <tt>Instruction</tt>s is straight-forward: simply call the
+constructor for the kind of instruction to instantiate and provide the necessary
+parameters. For example, an <tt>AllocaInst</tt> only <i>requires</i> a
+(const-ptr-to) <tt>Type</tt>. Thus:</p>
+
+<div class="doc_code">
+<pre>
+AllocaInst* ai = new AllocaInst(Type::Int32Ty);
+</pre>
+</div>
+
+<p>will create an <tt>AllocaInst</tt> instance that represents the allocation of
+one integer in the current stack frame, at run time. Each <tt>Instruction</tt>
+subclass is likely to have varying default parameters which change the semantics
+of the instruction, so refer to the <a
+href="/doxygen/classllvm_1_1Instruction.html">doxygen documentation for the subclass of
+Instruction</a> that you're interested in instantiating.</p>
+
+<p><i>Naming values</i></p>
+
+<p>It is very useful to name the values of instructions when you're able to, as
+this facilitates the debugging of your transformations. If you end up looking
+at generated LLVM machine code, you definitely want to have logical names
+associated with the results of instructions! By supplying a value for the
+<tt>Name</tt> (default) parameter of the <tt>Instruction</tt> constructor, you
+associate a logical name with the result of the instruction's execution at
+run time. For example, say that I'm writing a transformation that dynamically
+allocates space for an integer on the stack, and that integer is going to be
+used as some kind of index by some other code. To accomplish this, I place an
+<tt>AllocaInst</tt> at the first point in the first <tt>BasicBlock</tt> of some
+<tt>Function</tt>, and I'm intending to use it within the same
+<tt>Function</tt>. I might do:</p>
+
+<div class="doc_code">
+<pre>
+AllocaInst* pa = new AllocaInst(Type::Int32Ty, 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 run time stack.</p>
+
+<p><i>Inserting instructions</i></p>
+
+<p>There are essentially two ways to insert an <tt>Instruction</tt>
+into an existing sequence of instructions that form a <tt>BasicBlock</tt>:</p>
+
+<ul>
+ <li>Insertion into an explicit instruction list
+
+ <p>Given a <tt>BasicBlock* pb</tt>, an <tt>Instruction* pi</tt> within that
+ <tt>BasicBlock</tt>, and a newly-created instruction we wish to insert
+ before <tt>*pi</tt>, we do the following: </p>
+
+<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
+ classes provide constructors which take a pointer to a
+ <tt>BasicBlock</tt> to be appended to. For example code that
+ looked like: </p>
+
+<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>
+
+<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>
+
+ <li>Insertion into an implicit instruction list
+
+ <p><tt>Instruction</tt> instances that are already in <tt>BasicBlock</tt>s
+ are implicitly associated with an existing instruction list: the instruction
+ list of the enclosing basic block. Thus, we could have accomplished the same
+ thing as the above code without being given a <tt>BasicBlock</tt> by doing:
+ </p>
+
+<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
+ constructors which take (as a default parameter) a pointer to an
+ <tt>Instruction</tt> which the newly-created <tt>Instruction</tt> should
+ precede. That is, <tt>Instruction</tt> constructors are capable of
+ inserting the newly-created instance into the <tt>BasicBlock</tt> of a
+ provided instruction, immediately before that instruction. Using an
+ <tt>Instruction</tt> constructor with a <tt>insertBefore</tt> (default)
+ parameter, the above code becomes:</p>
+
+<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>
+</ul>
+
+</div>
+
+<!--_______________________________________________________________________-->
+<div class="doc_subsubsection">
+ <a name="schanges_deleting">Deleting <tt>Instruction</tt>s</a>
+</div>
+
+<div class="doc_text">
+
+<p>Deleting an instruction from an existing sequence of instructions that form a
+<a href="#BasicBlock"><tt>BasicBlock</tt></a> is very straight-forward. First,
+you must have a pointer to the instruction that you wish to delete. Second, you
+need to obtain the pointer to that instruction's basic block. You use the
+pointer to the basic block to get its list of instructions and then use the
+erase function to remove your instruction. For example:</p>
+
+<div class="doc_code">
+<pre>
+<a href="#Instruction">Instruction</a> *I = .. ;
+I->eraseFromParent();
+</pre>
+</div>
+
+</div>
+
+<!--_______________________________________________________________________-->
+<div class="doc_subsubsection">
+ <a name="schanges_replacing">Replacing an <tt>Instruction</tt> with another
+ <tt>Value</tt></a>
+</div>
+
+<div class="doc_text">
+
+<p><i>Replacing individual instructions</i></p>
+
+<p>Including "<a href="/doxygen/BasicBlockUtils_8h-source.html">llvm/Transforms/Utils/BasicBlockUtils.h</a>"
+permits use of two very useful replace functions: <tt>ReplaceInstWithValue</tt>
+and <tt>ReplaceInstWithInst</tt>.</p>
+
+<h4><a name="schanges_deleting">Deleting <tt>Instruction</tt>s</a></h4>
+
+<ul>
+ <li><tt>ReplaceInstWithValue</tt>
+
+ <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 a null
+ pointer to an integer.</p>
+
+<div class="doc_code">
+<pre>
+AllocaInst* instToReplace = ...;
+BasicBlock::iterator ii(instToReplace);
+
+ReplaceInstWithValue(instToReplace->getParent()->getInstList(), ii,
+ Constant::getNullValue(PointerType::get(Type::Int32Ty)));
+</pre></div></li>
+
+ <li><tt>ReplaceInstWithInst</tt>
+
+ <p>This function replaces a particular instruction with another
+ instruction. The following example illustrates the replacement of one
+ <tt>AllocaInst</tt> with another.</p>
+
+<div class="doc_code">
+<pre>
+AllocaInst* instToReplace = ...;
+BasicBlock::iterator ii(instToReplace);
+
+ReplaceInstWithInst(instToReplace->getParent()->getInstList(), ii,
+ new AllocaInst(Type::Int32Ty, 0, "ptrToReplacedInt"));
+</pre></div></li>
+</ul>
+
+<p><i>Replacing multiple uses of <tt>User</tt>s and <tt>Value</tt>s</i></p>
+
+<p>You can use <tt>Value::replaceAllUsesWith</tt> and
+<tt>User::replaceUsesOfWith</tt> to change more than one use at a time. See the
+doxygen documentation for the <a href="/doxygen/classllvm_1_1Value.html">Value Class</a>
+and <a href="/doxygen/classllvm_1_1User.html">User Class</a>, respectively, for more
+information.</p>
+
+<!-- Value::replaceAllUsesWith User::replaceUsesOfWith Point out:
+include/llvm/Transforms/Utils/ especially BasicBlockUtils.h with:
+ReplaceInstWithValue, ReplaceInstWithInst -->
+
+</div>
+
+<!--_______________________________________________________________________-->
+<div class="doc_subsubsection">
+ <a name="schanges_deletingGV">Deleting <tt>GlobalVariable</tt>s</a>
+</div>
+
+<div class="doc_text">
+
+<p>Deleting a global variable from a module is just as easy as deleting an
+Instruction. First, you must have a pointer to the global variable that you wish
+ to delete. You use this pointer to erase it from its parent, the module.
+ For example:</p>
+
+<div class="doc_code">
+<pre>
+<a href="#GlobalVariable">GlobalVariable</a> *GV = .. ;
+
+GV->eraseFromParent();
+</pre>
+</div>
+
+</div>
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="advanced">Advanced Topics</a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+<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="TypeResolve">LLVM Type Resolution</a>
+</div>
+
+<div class="doc_text">
+
+<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>
+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 bitcode reader,
+assembly parser, and linker also have to be aware of the inner workings of this
+system.
+</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, i32 }</tt>").
+Third, a concrete type is a type that is not an abstract type (e.g. "<tt>{ i32,
+float }</tt>").
+</p>
+
+</div>
+
+<!-- ______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="BuildRecType">Basic Recursive Type Construction</a>
+</div>
+
+<div class="doc_text">
+
+<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*, i32 }
+</pre>
+</div>
+
+<p>
+To build this, use the following LLVM APIs:
+</p>
+
+<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::Int32Ty);
+StructType *NewSTy = StructType::get(Elts);
+
+// <i>At this point, NewSTy = "{ opaque*, i32 }". 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);
+
+// <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());
+
+// <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
+href="#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_subsubsection">
+ <a name="refineAbstractTypeTo">The <tt>refineAbstractTypeTo</tt> method</a>
+</div>
+
+<div class="doc_text">
+<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>
+In the example above, the OpaqueType object is definitely deleted.
+Additionally, if there is an "{ \2*, i32}" 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>
+
+<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="AbstractTypeUser">The AbstractTypeUser Class</a>
+</div>
+
+<div class="doc_text">
+
+<p>
+Some data structures need more to perform more complex updates when types get
+resolved. 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 any opaque
+objects) can never be refined.
+</p>
+</div>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="SymbolTable">The <tt>ValueSymbolTable</tt> and
+ <tt>TypeSymbolTable</tt> classes</a>
+</div>
+
+<div class="doc_text">
+<p>The <tt><a href="http://llvm.org/doxygen/classllvm_1_1ValueSymbolTable.html">
+ValueSymbolTable</a></tt> 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 value definitions. The symbol table
+can provide a name for any <a href="#Value"><tt>Value</tt></a>.
+The <tt><a href="http://llvm.org/doxygen/classllvm_1_1TypeSymbolTable.html">
+TypeSymbolTable</a></tt> class is used by the <tt>Module</tt> class to store
+names for types.</p>
+
+<p>Note that the <tt>SymbolTable</tt> class 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>These symbol tables support iteration over the values/types in the symbol
+table with <tt>begin/end/iterator</tt> and supports querying to see if a
+specific name is in the symbol table (with <tt>lookup</tt>). The
+<tt>ValueSymbolTable</tt> class exposes no public mutator methods, instead,
+simply call <tt>setName</tt> on a value, which will autoinsert it into the
+appropriate symbol table. For types, use the Module::addTypeName method to
+insert entries into the symbol table.</p>
+
+</div>
+
+
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="coreclasses">The Core LLVM Class Hierarchy Reference </a>
+</div>
+<!-- *********************************************************************** -->
+
+<div class="doc_text">
+<p><tt>#include "<a href="/doxygen/Type_8h-source.html">llvm/Type.h</a>"</tt>
+<br>doxygen info: <a href="/doxygen/classllvm_1_1Type.html">Type Class</a></p>
+
+<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>