+</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 = .. ;
+<a href="#BasicBlock">BasicBlock</a> *BB = I->getParent();
+
+BB->getInstList().erase(I);
+</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::IntTy)));
+</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::IntTy, 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_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 bytecode 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::IntTy);
+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>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="Type">The <tt>Type</tt> class and Derived Types</a>
+</div>
+
+<div class="doc_text">
+
+ <p><tt>Type</tt> is a superclass of all type classes. Every <tt>Value</tt> has
+ a <tt>Type</tt>. <tt>Type</tt> cannot be instantiated directly but only
+ through its subclasses. Certain primitive types (<tt>VoidType</tt>,
+ <tt>LabelType</tt>, <tt>FloatType</tt> and <tt>DoubleType</tt>) have hidden
+ subclasses. They are hidden because they offer no useful functionality beyond
+ what the <tt>Type</tt> class offers except to distinguish themselves from
+ other subclasses of <tt>Type</tt>.</p>
+ <p>All other types are subclasses of <tt>DerivedType</tt>. Types can be
+ named, but this is not a requirement. There exists exactly
+ one instance of a given shape at any one time. This allows type equality to
+ be performed with address equality of the Type Instance. That is, given two
+ <tt>Type*</tt> values, the types are identical if the pointers are identical.
+ </p>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_Value">Important Public Methods</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+ <li><tt>bool isInteger() const</tt>: Returns true for any integer type.</li>
+
+ <li><tt>bool isFloatingPoint()</tt>: Return true if this is one of the two
+ floating point types.</li>
+
+ <li><tt>bool isAbstract()</tt>: Return true if the type is abstract (contains
+ an OpaqueType anywhere in its definition).</li>
+
+ <li><tt>bool isSized()</tt>: Return true if the type has known size. Things
+ that don't have a size are abstract types, labels and void.</li>
+
+</ul>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_Value">Important Derived Types</a>
+</div>
+<div class="doc_text">
+<dl>
+ <dt><tt>IntegerType</tt></dt>
+ <dd>Subclass of DerivedType that represents integer types of any bit width.
+ Any bit width between <tt>IntegerType::MIN_INT_BITS</tt> (1) and
+ <tt>IntegerType::MAX_INT_BITS</tt> (~8 million) can be represented.
+ <ul>
+ <li><tt>static const IntegerType* get(unsigned NumBits)</tt>: get an integer
+ type of a specific bit width.</li>
+ <li><tt>unsigned getBitWidth() const</tt>: Get the bit width of an integer
+ type.</li>
+ </ul>
+ </dd>
+ <dt><tt>SequentialType</tt></dt>
+ <dd>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>
+ </dd>
+ <dt><tt>ArrayType</tt></dt>
+ <dd>This is a subclass of SequentialType and defines the interface for array
+ types.
+ <ul>
+ <li><tt>unsigned getNumElements() const</tt>: Returns the number of
+ elements in the array. </li>
+ </ul>
+ </dd>
+ <dt><tt>PointerType</tt></dt>
+ <dd>Subclass of SequentialType for pointer types.</dd>
+ <dt><tt>VectorType</tt></dt>
+ <dd>Subclass of SequentialType for vector types. A
+ vector type is similar to an ArrayType but is distinguished because it is
+ a first class type wherease ArrayType is not. Vector types are used for
+ vector operations and are usually small vectors of of an integer or floating
+ point type.</dd>
+ <dt><tt>StructType</tt></dt>
+ <dd>Subclass of DerivedTypes for struct types.</dd>
+ <dt><tt><a name="FunctionType">FunctionType</a></tt></dt>
+ <dd>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>
+ </dd>
+ <dt><tt>OpaqueType</tt></dt>
+ <dd>Sublcass of DerivedType for abstract types. This class
+ defines no content and is used as a placeholder for some other type. Note
+ that OpaqueType is used (temporarily) during type resolution for forward
+ references of types. Once the referenced type is resolved, the OpaqueType
+ is replaced with the actual type. OpaqueType can also be used for data
+ abstraction. At link time opaque types can be resolved to actual types
+ of the same name.</dd>
+</dl>
+</div>
+
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="Module">The <tt>Module</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p><tt>#include "<a
+href="/doxygen/Module_8h-source.html">llvm/Module.h</a>"</tt><br> doxygen info:
+<a href="/doxygen/classllvm_1_1Module.html">Module Class</a></p>
+
+<p>The <tt>Module</tt> class represents the top level structure present in LLVM
+programs. An LLVM module is effectively either a translation unit of the
+original program or a combination of several translation units merged by the
+linker. The <tt>Module</tt> class keeps track of a list of <a
+href="#Function"><tt>Function</tt></a>s, a list of <a
+href="#GlobalVariable"><tt>GlobalVariable</tt></a>s, and a <a
+href="#SymbolTable"><tt>SymbolTable</tt></a>. Additionally, it contains a few
+helpful member functions that try to make common operations easy.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_Module">Important Public Members of the <tt>Module</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+ <li><tt>Module::Module(std::string name = "")</tt></li>
+</ul>
+
+<p>Constructing a <a href="#Module">Module</a> is easy. You can optionally
+provide a name for it (probably based on the name of the translation unit).</p>
+
+<ul>
+ <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>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>
+ list.</p></li>
+
+ <li><tt>Module::FunctionListType &getFunctionList()</tt>
+
+ <p> Returns the list of <a href="#Function"><tt>Function</tt></a>s. This is
+ necessary to use when you need to update the list or perform a complex
+ action that doesn't have a forwarding method.</p>
+
+ <p><!-- Global Variable --></p></li>
+</ul>
+
+<hr>
+
+<ul>
+ <li><tt>Module::global_iterator</tt> - Typedef for global variable list iterator<br>
+
+ <tt>Module::const_global_iterator</tt> - Typedef for const_iterator.<br>
+
+ <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
+ href="#GlobalVariable"><tt>GlobalVariable</tt></a> list.</p></li>
+
+ <li><tt>Module::GlobalListType &getGlobalList()</tt>
+
+ <p>Returns the list of <a
+ href="#GlobalVariable"><tt>GlobalVariable</tt></a>s. This is necessary to
+ use when you need to update the list or perform a complex action that
+ doesn't have a forwarding method.</p>
+
+ <p><!-- Symbol table stuff --> </p></li>
+</ul>
+
+<hr>
+
+<ul>
+ <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt>
+
+ <p>Return a reference to the <a href="#SymbolTable"><tt>SymbolTable</tt></a>
+ for this <tt>Module</tt>.</p>
+
+ <p><!-- Convenience methods --></p></li>
+</ul>
+
+<hr>
+
+<ul>
+ <li><tt><a href="#Function">Function</a> *getFunction(const std::string
+ &Name, const <a href="#FunctionType">FunctionType</a> *Ty)</tt>
+
+ <p>Look up the specified function in the <tt>Module</tt> <a
+ href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, return
+ <tt>null</tt>.</p></li>
+
+ <li><tt><a href="#Function">Function</a> *getOrInsertFunction(const
+ std::string &Name, const <a href="#FunctionType">FunctionType</a> *T)</tt>
+
+ <p>Look up the specified function in the <tt>Module</tt> <a
+ href="#SymbolTable"><tt>SymbolTable</tt></a>. If it does not exist, add an
+ external declaration for the function and return it.</p></li>
+
+ <li><tt>std::string getTypeName(const <a href="#Type">Type</a> *Ty)</tt>
+
+ <p>If there is at least one entry in the <a
+ href="#SymbolTable"><tt>SymbolTable</tt></a> for the specified <a
+ href="#Type"><tt>Type</tt></a>, return it. Otherwise return the empty
+ string.</p></li>
+
+ <li><tt>bool addTypeName(const std::string &Name, const <a
+ href="#Type">Type</a> *Ty)</tt>
+
+ <p>Insert an entry in the <a href="#SymbolTable"><tt>SymbolTable</tt></a>
+ mapping <tt>Name</tt> to <tt>Ty</tt>. If there is already an entry for this
+ name, true is returned and the <a
+ href="#SymbolTable"><tt>SymbolTable</tt></a> is not modified.</p></li>
+</ul>
+
+</div>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="Value">The <tt>Value</tt> class</a>
+</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/classllvm_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 i32 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::ICmp</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="#CmpInst">CmpInst</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_subsubsection">
+ <a name="s_Instruction">Important Subclasses of the <tt>Instruction</tt>
+ class</a>
+</div>
+<div class="doc_text">
+ <ul>
+ <li><tt><a name="BinaryOperator">BinaryOperator</a></tt>
+ <p>This subclasses represents all two operand instructions whose operands
+ must be the same type, except for the comparison instructions.</p></li>
+ <li><tt><a name="CastInst">CastInst</a></tt>
+ <p>This subclass is the parent of the 12 casting instructions. It provides
+ common operations on cast instructions.</p>
+ <li><tt><a name="CmpInst">CmpInst</a></tt>
+ <p>This subclass respresents the two comparison instructions,
+ <a href="LangRef.html#i_icmp">ICmpInst</a> (integer opreands), and
+ <a href="LangRef.html#i_fcmp">FCmpInst</a> (floating point operands).</p>
+ <li><tt><a name="TerminatorInst">TerminatorInst</a></tt>
+ <p>This subclass is the parent of all terminator instructions (those which
+ can terminate a block).</p>
+ </ul>
+ </div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_Instruction">Important Public Members of the <tt>Instruction</tt>
+ class</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+ <li><tt><a href="#BasicBlock">BasicBlock</a> *getParent()</tt>
+ <p>Returns the <a href="#BasicBlock"><tt>BasicBlock</tt></a> that
+this <tt>Instruction</tt> is embedded into.</p></li>
+ <li><tt>bool mayWriteToMemory()</tt>
+ <p>Returns true if the instruction writes to memory, i.e. it is a
+ <tt>call</tt>,<tt>free</tt>,<tt>invoke</tt>, or <tt>store</tt>.</p></li>
+ <li><tt>unsigned getOpcode()</tt>
+ <p>Returns the opcode for the <tt>Instruction</tt>.</p></li>
+ <li><tt><a href="#Instruction">Instruction</a> *clone() const</tt>
+ <p>Returns another instance of the specified instruction, identical
+in all ways to the original except that the instruction has no parent
+(ie it's not embedded into a <a href="#BasicBlock"><tt>BasicBlock</tt></a>),
+and it has no name</p></li>
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="Constant">The <tt>Constant</tt> class and subclasses</a>
+</div>
+
+<div class="doc_text">
+
+<p>Constant represents a base class for different types of constants. It
+is subclassed by ConstantInt, ConstantArray, etc. for representing
+the various types of Constants. <a href="#GlobalValue">GlobalValue</a> is also
+a subclass, which represents the address of a global variable or function.
+</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">Important Subclasses of Constant </div>
+<div class="doc_text">
+<ul>
+ <li>ConstantInt : This subclass of Constant represents an integer constant of
+ any width.
+ <ul>
+ <li><tt>const APInt& getValue() const</tt>: Returns the underlying
+ value of this constant, an APInt value.</li>
+ <li><tt>int64_t getSExtValue() const</tt>: Converts the underlying APInt
+ value to an int64_t via sign extension. If the value (not the bit width)
+ of the APInt is too large to fit in an int64_t, an assertion will result.
+ For this reason, use of this method is discouraged.</li>
+ <li><tt>uint64_t getZExtValue() const</tt>: Converts the underlying APInt
+ value to a uint64_t via zero extension. IF the value (not the bit width)
+ of the APInt is too large to fit in a uint64_t, an assertion will result.
+ For this reason, use of this method is discouraged.</li>
+ <li><tt>static ConstantInt* get(const APInt& Val)</tt>: Returns the
+ ConstantInt object that represents the value provided by <tt>Val</tt>.
+ The type is implied as the IntegerType that corresponds to the bit width
+ of <tt>Val</tt>.</li>
+ <li><tt>static ConstantInt* get(const Type *Ty, uint64_t Val)</tt>:
+ Returns the ConstantInt object that represents the value provided by
+ <tt>Val</tt> for integer type <tt>Ty</tt>.</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>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>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="GlobalValue">The <tt>GlobalValue</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<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="#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
+visible in the bodies of all <a href="#Function"><tt>Function</tt></a>s.
+Because they are visible at global scope, they are also subject to linking with
+other globals defined in different translation units. To control the linking
+process, <tt>GlobalValue</tt>s know their linkage rules. Specifically,
+<tt>GlobalValue</tt>s know whether they have internal or external linkage, as
+defined by the <tt>LinkageTypes</tt> enumeration.</p>
+
+<p>If a <tt>GlobalValue</tt> has internal linkage (equivalent to being
+<tt>static</tt> in C), it is not visible to code outside the current translation
+unit, and does not participate in linking. If it has external linkage, it is
+visible to external code, and does participate in linking. In addition to
+linkage information, <tt>GlobalValue</tt>s keep track of which <a
+href="#Module"><tt>Module</tt></a> they are currently part of.</p>
+
+<p>Because <tt>GlobalValue</tt>s are memory objects, they are always referred to
+by their <b>address</b>. As such, the <a href="#Type"><tt>Type</tt></a> of a
+global is always a pointer to its contents. It is important to remember this
+when using the <tt>GetElementPtrInst</tt> instruction because this pointer must
+be dereferenced first. For example, if you have a <tt>GlobalVariable</tt> (a
+subclass of <tt>GlobalValue)</tt> that is an array of 24 ints, type <tt>[24 x
+i32]</tt>, then the <tt>GlobalVariable</tt> is a pointer to that array. Although
+the address of the first element of this array and the value of the
+<tt>GlobalVariable</tt> are the same, they have different types. The
+<tt>GlobalVariable</tt>'s type is <tt>[24 x i32]</tt>. The first element's type
+is <tt>i32.</tt> Because of this, accessing a global value requires you to
+dereference the pointer with <tt>GetElementPtrInst</tt> first, then its elements
+can be accessed. This is explained in the <a href="LangRef.html#globalvars">LLVM
+Language Reference Manual</a>.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_GlobalValue">Important Public Members of the <tt>GlobalValue</tt>
+ class</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+ <li><tt>bool hasInternalLinkage() const</tt><br>
+ <tt>bool hasExternalLinkage() const</tt><br>
+ <tt>void setInternalLinkage(bool HasInternalLinkage)</tt>
+ <p> These methods manipulate the linkage characteristics of the <tt>GlobalValue</tt>.</p>
+ <p> </p>
+ </li>
+ <li><tt><a href="#Module">Module</a> *getParent()</tt>
+ <p> This returns the <a href="#Module"><tt>Module</tt></a> that the
+GlobalValue is currently embedded into.</p></li>
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="Function">The <tt>Function</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<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="#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>
+
+<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
+ordering of the blocks in the function, which indicate how the code will be
+layed out by the backend. Additionally, the first <a
+href="#BasicBlock"><tt>BasicBlock</tt></a> is the implicit entry node for the
+<tt>Function</tt>. It is not legal in LLVM to explicitly branch to this initial
+block. There are no implicit exit nodes, and in fact there may be multiple exit
+nodes from a single <tt>Function</tt>. If the <a
+href="#BasicBlock"><tt>BasicBlock</tt></a> list is empty, this indicates that
+the <tt>Function</tt> is actually a function declaration: the actual body of the
+function hasn't been linked in yet.</p>
+
+<p>In addition to a list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s, the
+<tt>Function</tt> class also keeps track of the list of formal <a
+href="#Argument"><tt>Argument</tt></a>s that the function receives. This
+container manages the lifetime of the <a href="#Argument"><tt>Argument</tt></a>
+nodes, just like the <a href="#BasicBlock"><tt>BasicBlock</tt></a> list does for
+the <a href="#BasicBlock"><tt>BasicBlock</tt></a>s.</p>
+
+<p>The <a href="#SymbolTable"><tt>SymbolTable</tt></a> is a very rarely used
+LLVM feature that is only used when you have to look up a value by name. Aside
+from that, the <a href="#SymbolTable"><tt>SymbolTable</tt></a> is used
+internally to make sure that there are not conflicts between the names of <a
+href="#Instruction"><tt>Instruction</tt></a>s, <a
+href="#BasicBlock"><tt>BasicBlock</tt></a>s, or <a
+href="#Argument"><tt>Argument</tt></a>s in the function body.</p>
+
+<p>Note that <tt>Function</tt> is a <a href="#GlobalValue">GlobalValue</a>
+and therefore also a <a href="#Constant">Constant</a>. The value of the function
+is its address (after linking) which is guaranteed to be constant.</p>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_Function">Important Public Members of the <tt>Function</tt>
+ class</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+ <li><tt>Function(const </tt><tt><a href="#FunctionType">FunctionType</a>
+ *Ty, LinkageTypes Linkage, const std::string &N = "", Module* Parent = 0)</tt>
+
+ <p>Constructor used when you need to create new <tt>Function</tt>s to add
+ the the program. The constructor must specify the type of the function to
+ create and what type of linkage the function should have. The <a
+ href="#FunctionType"><tt>FunctionType</tt></a> argument
+ specifies the formal arguments and return value for the function. The same
+ <a href="#FunctionType"><tt>FunctionType</tt></a> value can be used to
+ create multiple functions. The <tt>Parent</tt> argument specifies the Module
+ in which the function is defined. If this argument is provided, the function
+ will automatically be inserted into that module's list of
+ functions.</p></li>
+
+ <li><tt>bool isExternal()</tt>
+
+ <p>Return whether or not the <tt>Function</tt> has a body defined. If the
+ function is "external", it does not have a body, and thus must be resolved
+ by linking with a function defined in a different translation unit.</p></li>
+
+ <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>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>
+ list.</p></li>
+
+ <li><tt>Function::BasicBlockListType &getBasicBlockList()</tt>
+
+ <p>Returns the list of <a href="#BasicBlock"><tt>BasicBlock</tt></a>s. This
+ 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::arg_iterator</tt> - Typedef for the argument list
+iterator<br>
+ <tt>Function::const_arg_iterator</tt> - Typedef for const_iterator.<br>
+
+ <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>
+ list.</p></li>
+
+ <li><tt>Function::ArgumentListType &getArgumentList()</tt>
+
+ <p>Returns the list of <a href="#Argument"><tt>Argument</tt></a>s. This 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><a href="#BasicBlock">BasicBlock</a> &getEntryBlock()</tt>
+
+ <p>Returns the entry <a href="#BasicBlock"><tt>BasicBlock</tt></a> for the
+ function. Because the entry block for the function is always the first
+ block, this returns the first block of the <tt>Function</tt>.</p></li>
+
+ <li><tt><a href="#Type">Type</a> *getReturnType()</tt><br>
+ <tt><a href="#FunctionType">FunctionType</a> *getFunctionType()</tt>
+
+ <p>This traverses the <a href="#Type"><tt>Type</tt></a> of the
+ <tt>Function</tt> and returns the return type of the function, or the <a
+ href="#FunctionType"><tt>FunctionType</tt></a> of the actual
+ function.</p></li>
+
+ <li><tt><a href="#SymbolTable">SymbolTable</a> *getSymbolTable()</tt>
+
+ <p> Return a pointer to the <a href="#SymbolTable"><tt>SymbolTable</tt></a>
+ for this <tt>Function</tt>.</p></li>
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="GlobalVariable">The <tt>GlobalVariable</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p><tt>#include "<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="#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 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>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_GlobalVariable">Important Public Members of the
+ <tt>GlobalVariable</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+ <li><tt>GlobalVariable(const </tt><tt><a href="#Type">Type</a> *Ty, bool
+ isConstant, LinkageTypes& Linkage, <a href="#Constant">Constant</a>
+ *Initializer = 0, const std::string &Name = "", Module* Parent = 0)</tt>
+
+ <p>Create a new global variable of the specified type. If
+ <tt>isConstant</tt> is true then the global variable will be marked as
+ unchanging for the program. The Linkage parameter specifies the type of
+ linkage (internal, external, weak, linkonce, appending) for the variable. If
+ the linkage is InternalLinkage, WeakLinkage, or LinkOnceLinkage, then
+ the resultant global variable will have internal linkage. AppendingLinkage
+ concatenates together all instances (in different translation units) of the
+ variable into a single variable but is only applicable to arrays. See
+ the <a href="LangRef.html#modulestructure">LLVM Language Reference</a> for
+ further details on linkage types. Optionally an initializer, a name, and the
+ module to put the variable into may be specified for the global variable as
+ well.</p></li>
+
+ <li><tt>bool isConstant() const</tt>
+
+ <p>Returns true if this is a global variable that is known not to
+ be modified at runtime.</p></li>
+
+ <li><tt>bool hasInitializer()</tt>
+
+ <p>Returns true if this <tt>GlobalVariable</tt> has an intializer.</p></li>
+
+ <li><tt><a href="#Constant">Constant</a> *getInitializer()</tt>
+
+ <p>Returns the intial value for a <tt>GlobalVariable</tt>. It is not legal
+ to call this method if there is no initializer.</p></li>
+</ul>
+
+</div>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="BasicBlock">The <tt>BasicBlock</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p><tt>#include "<a
+href="/doxygen/BasicBlock_8h-source.html">llvm/BasicBlock.h</a>"</tt><br>
+doxygen info: <a href="/doxygen/structllvm_1_1BasicBlock.html">BasicBlock
+Class</a><br>
+Superclass: <a href="#Value"><tt>Value</tt></a></p>
+
+<p>This class represents a single entry multiple exit section of the code,
+commonly known as a basic block by the compiler community. The
+<tt>BasicBlock</tt> class maintains a list of <a
+href="#Instruction"><tt>Instruction</tt></a>s, which form the body of the block.
+Matching the language definition, the last element of this list of instructions
+is always a terminator instruction (a subclass of the <a
+href="#TerminatorInst"><tt>TerminatorInst</tt></a> class).</p>
+
+<p>In addition to tracking the list of instructions that make up the block, the
+<tt>BasicBlock</tt> class also keeps track of the <a
+href="#Function"><tt>Function</tt></a> that it is embedded into.</p>
+
+<p>Note that <tt>BasicBlock</tt>s themselves are <a
+href="#Value"><tt>Value</tt></a>s, because they are referenced by instructions
+like branches and can go in the switch tables. <tt>BasicBlock</tt>s have type
+<tt>label</tt>.</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="m_BasicBlock">Important Public Members of the <tt>BasicBlock</tt>
+ class</a>
+</div>
+
+<div class="doc_text">
+<ul>
+
+<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>
+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>
+
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="Argument">The <tt>Argument</tt> class</a>
+</div>
+
+<div class="doc_text">
+
+<p>This subclass of Value defines the interface for incoming 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>
+
+<!-- *********************************************************************** -->
+<hr>
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+ <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.org">The LLVM Compiler Infrastructure</a><br>
+ Last modified: $Date$
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