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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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+<html>
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+ <title>LLVM Assembly Language Reference Manual</title>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+ <meta name="author" content="Chris Lattner">
+ <meta name="description"
+ content="LLVM Assembly Language Reference Manual.">
+ <link rel="stylesheet" href="llvm.css" type="text/css">
+</head>
+
+<body>
+
+<div class="doc_title"> LLVM Language Reference Manual </div>
<ol>
- <li><a href="#abstract">Abstract</a>
- <li><a href="#introduction">Introduction</a>
- <li><a href="#identifiers">Identifiers</a>
+ <li><a href="#abstract">Abstract</a></li>
+ <li><a href="#introduction">Introduction</a></li>
+ <li><a href="#identifiers">Identifiers</a></li>
+ <li><a href="#highlevel">High Level Structure</a>
+ <ol>
+ <li><a href="#modulestructure">Module Structure</a></li>
+ <li><a href="#linkage">Linkage Types</a></li>
+ <li><a href="#globalvars">Global Variables</a></li>
+ <li><a href="#functionstructure">Function Structure</a></li>
+ </ol>
+ </li>
<li><a href="#typesystem">Type System</a>
<ol>
- <li><a href="#t_primitive">Primitive Types</a>
- <ol>
- <li><a href="#t_classifications">Type Classifications</a>
+ <li><a href="#t_primitive">Primitive Types</a>
+ <li><a href="#t_classifications">Type Classifications</a></li>
</ol>
+ </li>
<li><a href="#t_derived">Derived Types</a>
<ol>
- <li><a href="#t_array" >Array Type</a>
- <li><a href="#t_function">Function Type</a>
- <li><a href="#t_pointer">Pointer Type</a>
- <li><a href="#t_struct" >Structure Type</a>
- <!-- <li><a href="#t_packed" >Packed Type</a> -->
+ <li><a href="#t_array">Array Type</a></li>
+ <li><a href="#t_function">Function Type</a></li>
+ <li><a href="#t_pointer">Pointer Type</a></li>
+ <li><a href="#t_struct">Structure Type</a></li>
+ <li><a href="#t_packed">Packed Type</a></li>
</ol>
+ </li>
</ol>
- <li><a href="#highlevel">High Level Structure</a>
+ </li>
+ <li><a href="#constants">Constants</a>
<ol>
- <li><a href="#modulestructure">Module Structure</a>
- <li><a href="#globalvars">Global Variables</a>
- <li><a href="#functionstructure">Function Structure</a>
+ <li><a href="#simpleconstants">Simple Constants</a>
+ <li><a href="#aggregateconstants">Aggregate Constants</a>
+ <li><a href="#globalconstants">Global Variable and Function Addresses</a>
+ <li><a href="#undefvalues">Undefined Values</a>
+ <li><a href="#constantexprs">Constant Expressions</a>
</ol>
+ </li>
<li><a href="#instref">Instruction Reference</a>
<ol>
<li><a href="#terminators">Terminator Instructions</a>
<ol>
- <li><a href="#i_ret" >'<tt>ret</tt>' Instruction</a>
- <li><a href="#i_br" >'<tt>br</tt>' Instruction</a>
- <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a>
- <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a>
- <li><a href="#i_unwind" >'<tt>unwind</tt>' Instruction</a>
+ <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
+ <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
+ <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
+ <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
+ <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
+ <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
</ol>
+ </li>
<li><a href="#binaryops">Binary Operations</a>
<ol>
- <li><a href="#i_add" >'<tt>add</tt>' Instruction</a>
- <li><a href="#i_sub" >'<tt>sub</tt>' Instruction</a>
- <li><a href="#i_mul" >'<tt>mul</tt>' Instruction</a>
- <li><a href="#i_div" >'<tt>div</tt>' Instruction</a>
- <li><a href="#i_rem" >'<tt>rem</tt>' Instruction</a>
- <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a>
+ <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
+ <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
+ <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
+ <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
+ <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
+ <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
</ol>
+ </li>
<li><a href="#bitwiseops">Bitwise Binary Operations</a>
<ol>
- <li><a href="#i_and">'<tt>and</tt>' Instruction</a>
- <li><a href="#i_or" >'<tt>or</tt>' Instruction</a>
- <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a>
- <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a>
- <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a>
+ <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
+ <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
+ <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
+ <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
+ <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
</ol>
+ </li>
<li><a href="#memoryops">Memory Access Operations</a>
<ol>
- <li><a href="#i_malloc" >'<tt>malloc</tt>' Instruction</a>
- <li><a href="#i_free" >'<tt>free</tt>' Instruction</a>
- <li><a href="#i_alloca" >'<tt>alloca</tt>' Instruction</a>
- <li><a href="#i_load" >'<tt>load</tt>' Instruction</a>
- <li><a href="#i_store" >'<tt>store</tt>' Instruction</a>
- <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
+ <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
+ <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
+ <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
+ <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
+ <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
+ <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
</ol>
+ </li>
<li><a href="#otherops">Other Operations</a>
<ol>
- <li><a href="#i_phi" >'<tt>phi</tt>' Instruction</a>
- <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a>
- <li><a href="#i_call" >'<tt>call</tt>' Instruction</a>
- <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a>
- <li><a href="#i_vaarg" >'<tt>vaarg</tt>' Instruction</a>
+ <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
+ <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
+ <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
+ <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
+ <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a></li>
+ <li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li>
</ol>
+ </li>
</ol>
+ </li>
<li><a href="#intrinsics">Intrinsic Functions</a>
- <ol>
- <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
<ol>
- <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
- <li><a href="#i_va_end" >'<tt>llvm.va_end</tt>' Intrinsic</a>
- <li><a href="#i_va_copy" >'<tt>llvm.va_copy</tt>' Intrinsic</a>
+ <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
+ <ol>
+ <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
+ <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
+ <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
+ <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
+ <ol>
+ <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
+ <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
+ <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
+ <li><a href="#int_codegen">Code Generator Intrinsics</a>
+ <ol>
+ <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
+ <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
+ <li><a href="#int_os">Operating System Intrinsics</a>
+ <ol>
+ <li><a href="#i_readport">'<tt>llvm.readport</tt>' Intrinsic</a></li>
+ <li><a href="#i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a></li>
+ <li><a href="#i_readio">'<tt>llvm.readio</tt>' Intrinsic</a></li>
+ <li><a href="#i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a></li>
+ </ol>
+ <li><a href="#int_libc">Standard C Library Intrinsics</a>
+ <ol>
+ <li><a href="#i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a></li>
+ <li><a href="#i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a></li>
+ <li><a href="#i_memset">'<tt>llvm.memset</tt>' Intrinsic</a></li>
+ <li><a href="#i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
+ <li><a href="#int_debugger">Debugger intrinsics</a></li>
</ol>
- </ol>
-
- <p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a> and <A href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></b><p>
-
-
+ </li>
</ol>
+<div class="doc_author">
+ <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
+ and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
+</div>
<!-- *********************************************************************** -->
-<p><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
-<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="abstract">Abstract
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="abstract">Abstract </a></div>
<!-- *********************************************************************** -->
-<blockquote>
- This document is a reference manual for the LLVM assembly language. LLVM is
- an SSA based representation that provides type safety, low-level operations,
- flexibility, and the capability of representing 'all' high-level languages
- cleanly. It is the common code representation used throughout all phases of
- the LLVM compilation strategy.
-</blockquote>
-
-
-
+<div class="doc_text">
+<p>This document is a reference manual for the LLVM assembly language.
+LLVM is an SSA based representation that provides type safety,
+low-level operations, flexibility, and the capability of representing
+'all' high-level languages cleanly. It is the common code
+representation used throughout all phases of the LLVM compilation
+strategy.</p>
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
-<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="introduction">Introduction
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="introduction">Introduction</a> </div>
<!-- *********************************************************************** -->
-The LLVM code representation is designed to be used in three different forms: as
-an in-memory compiler IR, as an on-disk bytecode representation (suitable for
-fast loading by a Just-In-Time compiler), and as a human readable assembly
-language representation. This allows LLVM to provide a powerful intermediate
-representation for efficient compiler transformations and analysis, while
-providing a natural means to debug and visualize the transformations. The three
-different forms of LLVM are all equivalent. This document describes the human
-readable representation and notation.<p>
-
-The LLVM representation aims to be a light-weight and low-level while being
-expressive, typed, and extensible at the same time. It aims to be a "universal
-IR" of sorts, by being at a low enough level that high-level ideas may be
-cleanly mapped to it (similar to how microprocessors are "universal IR's",
-allowing many source languages to be mapped to them). By providing type
-information, LLVM can be used as the target of optimizations: for example,
-through pointer analysis, it can be proven that a C automatic variable is never
-accessed outside of the current function... allowing it to be promoted to a
-simple SSA value instead of a memory location.<p>
+<div class="doc_text">
+
+<p>The LLVM code representation is designed to be used in three
+different forms: as an in-memory compiler IR, as an on-disk bytecode
+representation (suitable for fast loading by a Just-In-Time compiler),
+and as a human readable assembly language representation. This allows
+LLVM to provide a powerful intermediate representation for efficient
+compiler transformations and analysis, while providing a natural means
+to debug and visualize the transformations. The three different forms
+of LLVM are all equivalent. This document describes the human readable
+representation and notation.</p>
+
+<p>The LLVM representation aims to be a light-weight and low-level
+while being expressive, typed, and extensible at the same time. It
+aims to be a "universal IR" of sorts, by being at a low enough level
+that high-level ideas may be cleanly mapped to it (similar to how
+microprocessors are "universal IR's", allowing many source languages to
+be mapped to them). By providing type information, LLVM can be used as
+the target of optimizations: for example, through pointer analysis, it
+can be proven that a C automatic variable is never accessed outside of
+the current function... allowing it to be promoted to a simple SSA
+value instead of a memory location.</p>
+
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="wellformed"><h4><hr size=0>Well Formedness</h4><ul>
+<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
+
+<div class="doc_text">
-It is important to note that this document describes 'well formed' LLVM assembly
-language. There is a difference between what the parser accepts and what is
-considered 'well formed'. For example, the following instruction is
-syntactically okay, but not well formed:<p>
+<p>It is important to note that this document describes 'well formed'
+LLVM assembly language. There is a difference between what the parser
+accepts and what is considered 'well formed'. For example, the
+following instruction is syntactically okay, but not well formed:</p>
<pre>
%x = <a href="#i_add">add</a> int 1, %x
</pre>
-...because the definition of <tt>%x</tt> does not dominate all of its uses. The
-LLVM infrastructure provides a verification pass that may be used to verify that
-an LLVM module is well formed. This pass is automatically run by the parser
-after parsing input assembly, and by the optimizer before it outputs bytecode.
-The violations pointed out by the verifier pass indicate bugs in transformation
-passes or input to the parser.<p>
-
-<!-- Describe the typesetting conventions here. -->
+<p>...because the definition of <tt>%x</tt> does not dominate all of
+its uses. The LLVM infrastructure provides a verification pass that may
+be used to verify that an LLVM module is well formed. This pass is
+automatically run by the parser after parsing input assembly, and by
+the optimizer before it outputs bytecode. The violations pointed out
+by the verifier pass indicate bugs in transformation passes or input to
+the parser.</p>
+<!-- Describe the typesetting conventions here. --> </div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
-<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="identifiers">Identifiers
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
<!-- *********************************************************************** -->
-LLVM uses three different forms of identifiers, for different purposes:<p>
+<div class="doc_text">
+
+<p>LLVM uses three different forms of identifiers, for different
+purposes:</p>
<ol>
-<li>Numeric constants are represented as you would expect: 12, -3 123.421, etc.
-Floating point constants have an optional hexidecimal notation.
-
-<li>Named values are represented as a string of characters with a '%' prefix.
-For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
-regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers
-which require other characters in their names can be surrounded with quotes. In
-this way, anything except a <tt>"</tt> character can be used in a name.
-
-<li>Unnamed values are represented as an unsigned numeric value with a '%'
-prefix. For example, %12, %2, %44.
-</ol><p>
-
-LLVM requires the values start with a '%' sign for two reasons: Compilers don't
-need to worry about name clashes with reserved words, and the set of reserved
-words may be expanded in the future without penalty. Additionally, unnamed
-identifiers allow a compiler to quickly come up with a temporary variable
-without having to avoid symbol table conflicts.<p>
-
-Reserved words in LLVM are very similar to reserved words in other languages.
-There are keywords for different opcodes ('<tt><a href="#i_add">add</a></tt>',
-'<tt><a href="#i_cast">cast</a></tt>', '<tt><a href="#i_ret">ret</a></tt>',
-etc...), for primitive type names ('<tt><a href="#t_void">void</a></tt>',
-'<tt><a href="#t_uint">uint</a></tt>', etc...), and others. These reserved
-words cannot conflict with variable names, because none of them start with a '%'
-character.<p>
-
-Here is an example of LLVM code to multiply the integer variable '<tt>%X</tt>'
-by 8:<p>
-
-The easy way:
+ <li>Named values are represented as a string of characters with a '%' prefix.
+ For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
+ regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
+ Identifiers which require other characters in their names can be surrounded
+ with quotes. In this way, anything except a <tt>"</tt> character can be used
+ in a name.</li>
+
+ <li>Unnamed values are represented as an unsigned numeric value with a '%'
+ prefix. For example, %12, %2, %44.</li>
+
+ <li>Constants, which are described in a <a href="#constants">section about
+ constants</a>, below.</li>
+</ol>
+
+<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
+don't need to worry about name clashes with reserved words, and the set of
+reserved words may be expanded in the future without penalty. Additionally,
+unnamed identifiers allow a compiler to quickly come up with a temporary
+variable without having to avoid symbol table conflicts.</p>
+
+<p>Reserved words in LLVM are very similar to reserved words in other
+languages. There are keywords for different opcodes ('<tt><a
+href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
+href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
+href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
+and others. These reserved words cannot conflict with variable names, because
+none of them start with a '%' character.</p>
+
+<p>Here is an example of LLVM code to multiply the integer variable
+'<tt>%X</tt>' by 8:</p>
+
+<p>The easy way:</p>
+
<pre>
%result = <a href="#i_mul">mul</a> uint %X, 8
</pre>
-After strength reduction:
+<p>After strength reduction:</p>
+
<pre>
%result = <a href="#i_shl">shl</a> uint %X, ubyte 3
</pre>
-And the hard way:
+<p>And the hard way:</p>
+
<pre>
<a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
<a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
%result = <a href="#i_add">add</a> uint %1, %1
</pre>
-This last way of multiplying <tt>%X</tt> by 8 illustrates several important lexical features of LLVM:<p>
+<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
+important lexical features of LLVM:</p>
<ol>
-<li>Comments are delimited with a '<tt>;</tt>' and go until the end of line.
-<li>Unnamed temporaries are created when the result of a computation is not
- assigned to a named value.
-<li>Unnamed temporaries are numbered sequentially
-</ol><p>
-...and it also show a convention that we follow in this document. When
+ <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
+ line.</li>
+
+ <li>Unnamed temporaries are created when the result of a computation is not
+ assigned to a named value.</li>
+
+ <li>Unnamed temporaries are numbered sequentially</li>
+
+</ol>
+
+<p>...and it also show a convention that we follow in this document. When
demonstrating instructions, we will follow an instruction with a comment that
defines the type and name of value produced. Comments are shown in italic
-text.<p>
-
-The one non-intuitive notation for constants is the optional hexidecimal form of
-floating point constants. For example, the form '<tt>double
-0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
-4.5e+15</tt>' which is also supported by the parser. The only time hexadecimal
-floating point constants are useful (and the only time that they are generated
-by the disassembler) is when an FP constant has to be emitted that is not
-representable as a decimal floating point number exactly. For example, NaN's,
-infinities, and other special cases are represented in their IEEE hexadecimal
-format so that assembly and disassembly do not cause any bits to change in the
-constants.<p>
+text.</p>
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
-<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="typesystem">Type System
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
<!-- *********************************************************************** -->
-The LLVM type system is one of the most important features of the intermediate
-representation. Being typed enables a number of optimizations to be performed
-on the IR directly, without having to do extra analyses on the side before the
-transformation. A strong type system makes it easier to read the generated code
-and enables novel analyses and transformations that are not feasible to perform
-on normal three address code representations.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
+</div>
-<!-- The written form for the type system was heavily influenced by the
-syntactic problems with types in the C language<sup><a
-href="#rw_stroustrup">1</a></sup>.<p> -->
+<div class="doc_text">
+<p>LLVM programs are composed of "Module"s, each of which is a
+translation unit of the input programs. Each module consists of
+functions, global variables, and symbol table entries. Modules may be
+combined together with the LLVM linker, which merges function (and
+global variable) definitions, resolves forward declarations, and merges
+symbol table entries. Here is an example of the "hello world" module:</p>
+<pre><i>; Declare the string constant as a global constant...</i>
+<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
+ href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="t_primitive">Primitive Types
-</b></font></td></tr></table><ul>
-
-The primitive types are the fundemental building blocks of the LLVM system. The
-current set of primitive types are as follows:<p>
-
-<table border=0 align=center><tr><td>
-
-<table border=1 cellspacing=0 cellpadding=4 align=center>
-<tr><td><tt>void</tt></td> <td>No value</td></tr>
-<tr><td><tt>ubyte</tt></td> <td>Unsigned 8 bit value</td></tr>
-<tr><td><tt>ushort</tt></td><td>Unsigned 16 bit value</td></tr>
-<tr><td><tt>uint</tt></td> <td>Unsigned 32 bit value</td></tr>
-<tr><td><tt>ulong</tt></td> <td>Unsigned 64 bit value</td></tr>
-<tr><td><tt>float</tt></td> <td>32 bit floating point value</td></tr>
-<tr><td><tt>label</tt></td> <td>Branch destination</td></tr>
-</table>
+<i>; External declaration of the puts function</i>
+<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
-</td><td valign=top>
+<i>; Definition of main function</i>
+int %main() { <i>; int()* </i>
+ <i>; Convert [13x sbyte]* to sbyte *...</i>
+ %cast210 = <a
+ href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
-<table border=1 cellspacing=0 cellpadding=4 align=center>
-<tr><td><tt>bool</tt></td> <td>True or False value</td></tr>
-<tr><td><tt>sbyte</tt></td> <td>Signed 8 bit value</td></tr>
-<tr><td><tt>short</tt></td> <td>Signed 16 bit value</td></tr>
-<tr><td><tt>int</tt></td> <td>Signed 32 bit value</td></tr>
-<tr><td><tt>long</tt></td> <td>Signed 64 bit value</td></tr>
-<tr><td><tt>double</tt></td><td>64 bit floating point value</td></tr>
-</table>
+ <i>; Call puts function to write out the string to stdout...</i>
+ <a
+ href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
+ <a
+ href="#i_ret">ret</a> int 0<br>}<br></pre>
-</td></tr></table><p>
+<p>This example is made up of a <a href="#globalvars">global variable</a>
+named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
+function, and a <a href="#functionstructure">function definition</a>
+for "<tt>main</tt>".</p>
+<p>In general, a module is made up of a list of global values,
+where both functions and global variables are global values. Global values are
+represented by a pointer to a memory location (in this case, a pointer to an
+array of char, and a pointer to a function), and have one of the following <a
+href="#linkage">linkage types</a>.</p>
+</div>
-<!-- _______________________________________________________________________ -->
-</ul><a name="t_classifications"><h4><hr size=0>Type Classifications</h4><ul>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="linkage">Linkage Types</a>
+</div>
-These different primitive types fall into a few useful classifications:<p>
+<div class="doc_text">
-<table border=1 cellspacing=0 cellpadding=4 align=center>
-<tr><td><a name="t_signed">signed</td> <td><tt>sbyte, short, int, long, float, double</tt></td></tr>
-<tr><td><a name="t_unsigned">unsigned</td><td><tt>ubyte, ushort, uint, ulong</tt></td></tr>
-<tr><td><a name="t_integer">integer</td><td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td></tr>
-<tr><td><a name="t_integral">integral</td><td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td></tr>
-<tr><td><a name="t_floating">floating point</td><td><tt>float, double</tt></td></tr>
-<tr><td><a name="t_firstclass">first class</td><td><tt>bool, ubyte, sbyte, ushort, short,<br> uint, int, ulong, long, float, double, <a href="#t_pointer">pointer</a></tt></td></tr>
-</table><p>
+<p>
+All Global Variables and Functions have one of the following types of linkage:
+</p>
+<dl>
+ <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
+ <dd>Global values with internal linkage are only directly accessible by
+ objects in the current module. In particular, linking code into a module with
+ an internal global value may cause the internal to be renamed as necessary to
+ avoid collisions. Because the symbol is internal to the module, all
+ references can be updated. This corresponds to the notion of the
+ '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
+ </dd>
+ <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="t_derived">Derived Types
-</b></font></td></tr></table><ul>
+ <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
+ the twist that linking together two modules defining the same
+ <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
+ is typically used to implement inline functions. Unreferenced
+ <tt>linkonce</tt> globals are allowed to be discarded.
+ </dd>
-The real power in LLVM comes from the derived types in the system. This is what
-allows a programmer to represent arrays, functions, pointers, and other useful
-types. Note that these derived types may be recursive: For example, it is
-possible to have a two dimensional array.<p>
+ <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
+ <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
+ except that unreferenced <tt>weak</tt> globals may not be discarded. This is
+ used to implement constructs in C such as "<tt>int X;</tt>" at global scope.
+ </dd>
+ <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
-<!-- _______________________________________________________________________ -->
-</ul><a name="t_array"><h4><hr size=0>Array Type</h4><ul>
+ <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
+ pointer to array type. When two global variables with appending linkage are
+ linked together, the two global arrays are appended together. This is the
+ LLVM, typesafe, equivalent of having the system linker append together
+ "sections" with identical names when .o files are linked.
+ </dd>
-<h5>Overview:</h5>
+ <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
-The array type is a very simple derived type that arranges elements sequentially
-in memory. The array type requires a size (number of elements) and an
-underlying data type.<p>
+ <dd>If none of the above identifiers are used, the global is externally
+ visible, meaning that it participates in linkage and can be used to resolve
+ external symbol references.
+ </dd>
+</dl>
-<h5>Syntax:</h5>
-<pre>
- [<# elements> x <elementtype>]
-</pre>
+<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
+variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
+variable and was linked with this one, one of the two would be renamed,
+preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
+external (i.e., lacking any linkage declarations), they are accessible
+outside of the current module. It is illegal for a function <i>declaration</i>
+to have any linkage type other than "externally visible".</a></p>
-The number of elements is a constant integer value, elementtype may be any type
-with a size.<p>
+</div>
-<h5>Examples:</h5>
-<ul>
- <tt>[40 x int ]</tt>: Array of 40 integer values.<br>
- <tt>[41 x int ]</tt>: Array of 41 integer values.<br>
- <tt>[40 x uint]</tt>: Array of 40 unsigned integer values.<p>
-</ul>
-
-Here are some examples of multidimensional arrays:<p>
-<ul>
-<table border=0 cellpadding=0 cellspacing=0>
-<tr><td><tt>[3 x [4 x int]]</tt></td><td>: 3x4 array integer values.</td></tr>
-<tr><td><tt>[12 x [10 x float]]</tt></td><td>: 12x10 array of single precision floating point values.</td></tr>
-<tr><td><tt>[2 x [3 x [4 x uint]]]</tt></td><td>: 2x3x4 array of unsigned integer values.</td></tr>
-</table>
-</ul>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="globalvars">Global Variables</a>
+</div>
+<div class="doc_text">
-<!-- _______________________________________________________________________ -->
-</ul><a name="t_function"><h4><hr size=0>Function Type</h4><ul>
+<p>Global variables define regions of memory allocated at compilation
+time instead of run-time. Global variables may optionally be
+initialized. A variable may be defined as a global "constant", which
+indicates that the contents of the variable will never be modified
+(enabling better optimization, allowing the global data to be placed in the
+read-only section of an executable, etc).</p>
-<h5>Overview:</h5>
+<p>As SSA values, global variables define pointer values that are in
+scope (i.e. they dominate) all basic blocks in the program. Global
+variables always define a pointer to their "content" type because they
+describe a region of memory, and all memory objects in LLVM are
+accessed through pointers.</p>
-The function type can be thought of as a function signature. It consists of a
-return type and a list of formal parameter types. Function types are usually
-used when to build virtual function tables (which are structures of pointers to
-functions), for indirect function calls, and when defining a function.<p>
+</div>
-<h5>Syntax:</h5>
-<pre>
- <returntype> (<parameter list>)
-</pre>
-Where '<tt><parameter list></tt>' is a comma-separated list of type
-specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
-which indicates that the function takes a variable number of arguments.
-Variable argument functions can access their arguments with the <a
-href="#int_varargs">variable argument handling intrinsic</a> functions.
-<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="functionstructure">Functions</a>
+</div>
-<h5>Examples:</h5>
-<ul>
-<table border=0 cellpadding=0 cellspacing=0>
+<div class="doc_text">
-<tr><td><tt>int (int)</tt></td><td>: function taking an <tt>int</tt>, returning
-an <tt>int</tt></td></tr>
+<p>LLVM function definitions are composed of a (possibly empty) argument list,
+an opening curly brace, a list of basic blocks, and a closing curly brace. LLVM
+function declarations are defined with the "<tt>declare</tt>" keyword, a
+function name, and a function signature.</p>
+
+<p>A function definition contains a list of basic blocks, forming the CFG for
+the function. Each basic block may optionally start with a label (giving the
+basic block a symbol table entry), contains a list of instructions, and ends
+with a <a href="#terminators">terminator</a> instruction (such as a branch or
+function return).</p>
-<tr><td><tt>float (int, int *) *</tt></td><td>: <a href="#t_pointer">Pointer</a>
-to a function that takes an <tt>int</tt> and a <a href="#t_pointer">pointer</a>
-to <tt>int</tt>, returning <tt>float</tt>.</td></tr>
+<p>The first basic block in program is special in two ways: it is immediately
+executed on entrance to the function, and it is not allowed to have predecessor
+basic blocks (i.e. there can not be any branches to the entry block of a
+function). Because the block can have no predecessors, it also cannot have any
+<a href="#i_phi">PHI nodes</a>.</p>
-<tr><td><tt>int (sbyte *, ...)</tt></td><td>: A vararg function that takes at
-least one <a href="#t_pointer">pointer</a> to <tt>sbyte</tt> (signed char in C),
-which returns an integer. This is the signature for <tt>printf</tt> in
-LLVM.</td></tr>
+<p>LLVM functions are identified by their name and type signature. Hence, two
+functions with the same name but different parameter lists or return values are
+considered different functions, and LLVM will resolves references to each
+appropriately.</p>
-</table>
-</ul>
+</div>
-<!-- _______________________________________________________________________ -->
-</ul><a name="t_struct"><h4><hr size=0>Structure Type</h4><ul>
+<!-- *********************************************************************** -->
+<div class="doc_section"> <a name="typesystem">Type System</a> </div>
+<!-- *********************************************************************** -->
-<h5>Overview:</h5>
+<div class="doc_text">
-The structure type is used to represent a collection of data members together in
-memory. The packing of the field types is defined to match the ABI of the
-underlying processor. The elements of a structure may be any type that has a
-size.<p>
+<p>The LLVM type system is one of the most important features of the
+intermediate representation. Being typed enables a number of
+optimizations to be performed on the IR directly, without having to do
+extra analyses on the side before the transformation. A strong type
+system makes it easier to read the generated code and enables novel
+analyses and transformations that are not feasible to perform on normal
+three address code representations.</p>
-Structures are accessed using '<tt><a href="#i_load">load</a></tt> and '<tt><a
-href="#i_store">store</a></tt>' by getting a pointer to a field with the '<tt><a
-href="#i_getelementptr">getelementptr</a></tt>' instruction.<p>
+</div>
-<h5>Syntax:</h5>
-<pre>
- { <type list> }
-</pre>
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
+<div class="doc_text">
+<p>The primitive types are the fundamental building blocks of the LLVM
+system. The current set of primitive types are as follows:</p>
+
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <table>
+ <tbody>
+ <tr><th>Type</th><th>Description</th></tr>
+ <tr><td><tt>void</tt></td><td>No value</td></tr>
+ <tr><td><tt>ubyte</tt></td><td>Unsigned 8 bit value</td></tr>
+ <tr><td><tt>ushort</tt></td><td>Unsigned 16 bit value</td></tr>
+ <tr><td><tt>uint</tt></td><td>Unsigned 32 bit value</td></tr>
+ <tr><td><tt>ulong</tt></td><td>Unsigned 64 bit value</td></tr>
+ <tr><td><tt>float</tt></td><td>32 bit floating point value</td></tr>
+ <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
+ </tbody>
+ </table>
+ </td>
+ <td class="right">
+ <table>
+ <tbody>
+ <tr><th>Type</th><th>Description</th></tr>
+ <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
+ <tr><td><tt>sbyte</tt></td><td>Signed 8 bit value</td></tr>
+ <tr><td><tt>short</tt></td><td>Signed 16 bit value</td></tr>
+ <tr><td><tt>int</tt></td><td>Signed 32 bit value</td></tr>
+ <tr><td><tt>long</tt></td><td>Signed 64 bit value</td></tr>
+ <tr><td><tt>double</tt></td><td>64 bit floating point value</td></tr>
+ </tbody>
+ </table>
+ </td>
+ </tr>
+</table>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="t_classifications">Type
+Classifications</a> </div>
+<div class="doc_text">
+<p>These different primitive types fall into a few useful
+classifications:</p>
+
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr><th>Classification</th><th>Types</th></tr>
+ <tr>
+ <td><a name="t_signed">signed</a></td>
+ <td><tt>sbyte, short, int, long, float, double</tt></td>
+ </tr>
+ <tr>
+ <td><a name="t_unsigned">unsigned</a></td>
+ <td><tt>ubyte, ushort, uint, ulong</tt></td>
+ </tr>
+ <tr>
+ <td><a name="t_integer">integer</a></td>
+ <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
+ </tr>
+ <tr>
+ <td><a name="t_integral">integral</a></td>
+ <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
+ </td>
+ </tr>
+ <tr>
+ <td><a name="t_floating">floating point</a></td>
+ <td><tt>float, double</tt></td>
+ </tr>
+ <tr>
+ <td><a name="t_firstclass">first class</a></td>
+ <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
+ float, double, <a href="#t_pointer">pointer</a>,
+ <a href="#t_packed">packed</a></tt></td>
+ </tr>
+ </tbody>
+</table>
-<h5>Examples:</h5>
-<table border=0 cellpadding=0 cellspacing=0>
+<p>The <a href="#t_firstclass">first class</a> types are perhaps the
+most important. Values of these types are the only ones which can be
+produced by instructions, passed as arguments, or used as operands to
+instructions. This means that all structures and arrays must be
+manipulated either by pointer or by component.</p>
+</div>
-<tr><td><tt>{ int, int, int }</tt></td><td>: a triple of three <tt>int</tt>
-values</td></tr>
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
-<tr><td><tt>{ float, int (int) * }</tt></td><td>: A pair, where the first
-element is a <tt>float</tt> and the second element is a <a
-href="#t_pointer">pointer</a> to a <a href="t_function">function</a> that takes
-an <tt>int</tt>, returning an <tt>int</tt>.</td></tr>
+<div class="doc_text">
-</table>
+<p>The real power in LLVM comes from the derived types in the system.
+This is what allows a programmer to represent arrays, functions,
+pointers, and other useful types. Note that these derived types may be
+recursive: For example, it is possible to have a two dimensional array.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="t_pointer"><h4><hr size=0>Pointer Type</h4><ul>
+<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
+
+<div class="doc_text">
<h5>Overview:</h5>
-As in many languages, the pointer type represents a pointer or reference to
-another object, which must live in memory.<p>
+<p>The array type is a very simple derived type that arranges elements
+sequentially in memory. The array type requires a size (number of
+elements) and an underlying data type.</p>
<h5>Syntax:</h5>
+
<pre>
- <type> *
+ [<# elements> x <elementtype>]
</pre>
-<h5>Examples:</h5>
-
-<table border=0 cellpadding=0 cellspacing=0>
-
-<tr><td><tt>[4x int]*</tt></td><td>: <a href="#t_pointer">pointer</a> to <a
-href="#t_array">array</a> of four <tt>int</tt> values</td></tr>
-
-<tr><td><tt>int (int *) *</tt></td><td>: A <a href="#t_pointer">pointer</a> to a
-<a href="t_function">function</a> that takes an <tt>int</tt>, returning an
-<tt>int</tt>.</td></tr>
+<p>The number of elements is a constant integer value, elementtype may
+be any type with a size.</p>
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>[40 x int ]</tt><br/>
+ <tt>[41 x int ]</tt><br/>
+ <tt>[40 x uint]</tt><br/>
+ </td>
+ <td class="left">
+ Array of 40 integer values.<br/>
+ Array of 41 integer values.<br/>
+ Array of 40 unsigned integer values.<br/>
+ </td>
+ </tr>
</table>
-<p>
-
+<p>Here are some examples of multidimensional arrays:</p>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>[3 x [4 x int]]</tt><br/>
+ <tt>[12 x [10 x float]]</tt><br/>
+ <tt>[2 x [3 x [4 x uint]]]</tt><br/>
+ </td>
+ <td class="left">
+ 3x4 array integer values.<br/>
+ 12x10 array of single precision floating point values.<br/>
+ 2x3x4 array of unsigned integer values.<br/>
+ </td>
+ </tr>
+</table>
+</div>
<!-- _______________________________________________________________________ -->
-<!--
-</ul><a name="t_packed"><h4><hr size=0>Packed Type</h4><ul>
-
-Mention/decide that packed types work with saturation or not. Maybe have a packed+saturated type in addition to just a packed type.<p>
+<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
+<div class="doc_text">
+<h5>Overview:</h5>
+<p>The function type can be thought of as a function signature. It
+consists of a return type and a list of formal parameter types.
+Function types are usually used to build virtual function tables
+(which are structures of pointers to functions), for indirect function
+calls, and when defining a function.</p>
+<p>
+The return type of a function type cannot be an aggregate type.
+</p>
+<h5>Syntax:</h5>
+<pre> <returntype> (<parameter list>)<br></pre>
+<p>Where '<tt><parameter list></tt>' is a comma-separated list of type
+specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
+which indicates that the function takes a variable number of arguments.
+Variable argument functions can access their arguments with the <a
+ href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>int (int)</tt> <br/>
+ <tt>float (int, int *) *</tt><br/>
+ <tt>int (sbyte *, ...)</tt><br/>
+ </td>
+ <td class="left">
+ function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
+ <a href="#t_pointer">Pointer</a> to a function that takes an
+ <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
+ returning <tt>float</tt>.<br/>
+ A vararg function that takes at least one <a href="#t_pointer">pointer</a>
+ to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
+ the signature for <tt>printf</tt> in LLVM.<br/>
+ </td>
+ </tr>
+</table>
-Packed types should be 'nonsaturated' because standard data types are not saturated. Maybe have a saturated packed type?<p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
+<div class="doc_text">
+<h5>Overview:</h5>
+<p>The structure type is used to represent a collection of data members
+together in memory. The packing of the field types is defined to match
+the ABI of the underlying processor. The elements of a structure may
+be any type that has a size.</p>
+<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
+and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
+field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
+instruction.</p>
+<h5>Syntax:</h5>
+<pre> { <type list> }<br></pre>
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>{ int, int, int }</tt><br/>
+ <tt>{ float, int (int) * }</tt><br/>
+ </td>
+ <td class="left">
+ a triple of three <tt>int</tt> values<br/>
+ A pair, where the first element is a <tt>float</tt> and the second element
+ is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
+ that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
+ </td>
+ </tr>
+</table>
+</div>
--->
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
+<div class="doc_text">
+<h5>Overview:</h5>
+<p>As in many languages, the pointer type represents a pointer or
+reference to another object, which must live in memory.</p>
+<h5>Syntax:</h5>
+<pre> <type> *<br></pre>
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>[4x int]*</tt><br/>
+ <tt>int (int *) *</tt><br/>
+ </td>
+ <td class="left">
+ A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
+ four <tt>int</tt> values<br/>
+ A <a href="#t_pointer">pointer</a> to a <a
+ href="#t_function">function</a> that takes an <tt>int</tt>, returning an
+ <tt>int</tt>.<br/>
+ </td>
+ </tr>
+</table>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
+<div class="doc_text">
+<h5>Overview:</h5>
+<p>A packed type is a simple derived type that represents a vector
+of elements. Packed types are used when multiple primitive data
+are operated in parallel using a single instruction (SIMD).
+A packed type requires a size (number of
+elements) and an underlying primitive data type. Packed types are
+considered <a href="#t_firstclass">first class</a>.</p>
+<h5>Syntax:</h5>
+<pre> < <# elements> x <elementtype> ><br></pre>
+<p>The number of elements is a constant integer value, elementtype may
+be any integral or floating point type.</p>
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt><4 x int></tt><br/>
+ <tt><8 x float></tt><br/>
+ <tt><2 x uint></tt><br/>
+ </td>
+ <td class="left">
+ Packed vector of 4 integer values.<br/>
+ Packed vector of 8 floating-point values.<br/>
+ Packed vector of 2 unsigned integer values.<br/>
+ </td>
+ </tr>
+</table>
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
-<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="highlevel">High Level Structure
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="constants">Constants</a> </div>
<!-- *********************************************************************** -->
+<div class="doc_text">
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="modulestructure">Module Structure
-</b></font></td></tr></table><ul>
+<p>LLVM has several different basic types of constants. This section describes
+them all and their syntax.</p>
-LLVM programs are composed of "Module"s, each of which is a translation unit of
-the input programs. Each module consists of functions, global variables, and
-symbol table entries. Modules may be combined together with the LLVM linker,
-which merges function (and global variable) definitions, resolves forward
-declarations, and merges symbol table entries. Here is an example of the "hello world" module:<p>
+</div>
-<pre>
-<i>; Declare the string constant as a global constant...</i>
-<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
-<i>; External declaration of the puts function</i>
-<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
+<div class="doc_text">
-<i>; Definition of main function</i>
-int %main() { <i>; int()* </i>
- <i>; Convert [13x sbyte]* to sbyte *...</i>
- %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
+<dl>
+ <dt><b>Boolean constants</b></dt>
- <i>; Call puts function to write out the string to stdout...</i>
- <a href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
- <a href="#i_ret">ret</a> int 0
-}
-</pre>
+ <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
+ constants of the <tt><a href="#t_primitive">bool</a></tt> type.
+ </dd>
-This example is made up of a <a href="#globalvars">global variable</a> named
-"<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and a
-<a href="#functionstructure">function definition</a> for "<tt>main</tt>".<p>
+ <dt><b>Integer constants</b></dt>
-<a name="linkage">
-In general, a module is made up of a list of global values, where both functions
-and global variables are global values. Global values are represented by a
-pointer to a memory location (in this case, a pointer to an array of char, and a
-pointer to a function), and have one of the following linkage types:<p>
+ <dd>Standard integers (such as '4') are constants of the <a
+ href="#t_integer">integer</a> type. Negative numbers may be used with signed
+ integer types.
+ </dd>
-<dl>
-<a name="linkage_internal">
-<dt><tt><b>internal</b></tt>
+ <dt><b>Floating point constants</b></dt>
-<dd>Global values with internal linkage are only directly accessible by objects
-in the current module. In particular, linking code into a module with an
-internal global value may cause the internal to be renamed as necessary to avoid
-collisions. Because the symbol is internal to the module, all references can be
-updated. This corresponds to the notion of the '<tt>static</tt>' keyword in C,
-or the idea of "anonymous namespaces" in C++.<p>
+ <dd>Floating point constants use standard decimal notation (e.g. 123.421),
+ exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
+ notation. Floating point constants have an optional hexadecimal
+ notation (see below). Floating point constants must have a <a
+ href="#t_floating">floating point</a> type. </dd>
-<a name="linkage_linkonce">
-<dt><tt><b>linkonce</b></tt>:
+ <dt><b>Null pointer constants</b></dt>
-<dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
-the twist that linking together two modules defining the same <tt>linkonce</tt>
-globals will cause one of the globals to be discarded. This is typically used
-to implement inline functions. Unreferenced <tt>linkonce</tt> globals are
-allowed to be discarded.<p>
+ <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
+ and must be of <a href="#t_pointer">pointer type</a>.</dd>
-<a name="linkage_weak">
-<dt><tt><b>weak</b></tt>:
+</dl>
-<dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
-except that unreferenced <tt>weak</tt> globals may not be discarded. This is
-used to implement constructs in C such as "<tt>int X;</tt>" at global scope.<p>
+<p>The one non-intuitive notation for constants is the optional hexadecimal form
+of floating point constants. For example, the form '<tt>double
+0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
+4.5e+15</tt>'. The only time hexadecimal floating point constants are required
+(and the only time that they are generated by the disassembler) is when a
+floating point constant must be emitted but it cannot be represented as a
+decimal floating point number. For example, NaN's, infinities, and other
+special values are represented in their IEEE hexadecimal format so that
+assembly and disassembly do not cause any bits to change in the constants.</p>
+
+</div>
-<a name="linkage_appending">
-<dt><tt><b>appending</b></tt>:
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
+</div>
-<dd>"<tt>appending</tt>" linkage may only applied to global variables of pointer
-to array type. When two global variables with appending linkage are linked
-together, the two global arrays are appended together. This is the LLVM,
-typesafe, equivalent of having the system linker append together "sections" with
-identical names when .o files are linked.<p>
+<div class="doc_text">
-<a name="linkage_external">
-<dt><tt><b>externally visible</b></tt>:
+<dl>
+ <dt><b>Structure constants</b></dt>
+
+ <dd>Structure constants are represented with notation similar to structure
+ type definitions (a comma separated list of elements, surrounded by braces
+ (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0 }</tt>". Structure
+ constants must have <a href="#t_struct">structure type</a>, and the number and
+ types of elements must match those specified by the type.
+ </dd>
+
+ <dt><b>Array constants</b></dt>
+
+ <dd>Array constants are represented with notation similar to array type
+ definitions (a comma separated list of elements, surrounded by square brackets
+ (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
+ constants must have <a href="#t_array">array type</a>, and the number and
+ types of elements must match those specified by the type.
+ </dd>
+
+ <dt><b>Packed constants</b></dt>
+
+ <dd>Packed constants are represented with notation similar to packed type
+ definitions (a comma separated list of elements, surrounded by
+ less-than/greater-than's (<tt><></tt>)). For example: "<tt>< int 42,
+ int 11, int 74, int 100 ></tt>". Packed constants must have <a
+ href="#t_packed">packed type</a>, and the number and types of elements must
+ match those specified by the type.
+ </dd>
+
+ <dt><b>Zero initialization</b></dt>
+
+ <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
+ value to zero of <em>any</em> type, including scalar and aggregate types.
+ This is often used to avoid having to print large zero initializers (e.g. for
+ large arrays), and is always exactly equivalent to using explicit zero
+ initializers.
+ </dd>
+</dl>
+
+</div>
-<dd>If none of the above identifiers are used, the global is externally visible,
-meaning that it participates in linkage and can be used to resolve external
-symbol references.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="globalconstants">Global Variable and Function Addresses</a>
+</div>
-</dl><p>
+<div class="doc_text">
+<p>The addresses of <a href="#globalvars">global variables</a> and <a
+href="#functionstructure">functions</a> are always implicitly valid (link-time)
+constants. These constants are explicitly referenced when the <a
+href="#identifiers">identifier for the global</a> is used and always have <a
+href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
+file:</p>
-For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
-another module defined a "<tt>.LC0</tt>" variable and was linked with this one,
-one of the two would be renamed, preventing a collision. Since "<tt>main</tt>"
-and "<tt>puts</tt>" are external (i.e., lacking any linkage declarations), they
-are accessible outside of the current module. It is illegal for a function
-<i>declaration</i> to have any linkage type other than "externally visible".<p>
+<pre>
+ %X = global int 17
+ %Y = global int 42
+ %Z = global [2 x int*] [ int* %X, int* %Y ]
+</pre>
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="globalvars">Global Variables
-</b></font></td></tr></table><ul>
+<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
+<div class="doc_text">
+ <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
+ no specific value. Undefined values may be of any type, and be used anywhere
+ a constant is permitted.</p>
+
+ <p>Undefined values indicate to the compiler that the program is well defined
+ no matter what value is used, giving the compiler more freedom to optimize.
+ </p>
+</div>
-Global variables define regions of memory allocated at compilation time instead
-of run-time. Global variables may optionally be initialized. A variable may
-be defined as a global "constant", which indicates that the contents of the
-variable will never be modified (opening options for optimization). Constants
-must always have an initial value.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
+</div>
-As SSA values, global variables define pointer values that are in scope
-(i.e. they dominate) for all basic blocks in the program. Global variables
-always define a pointer to their "content" type because they describe a region
-of memory, and all memory objects in LLVM are accessed through pointers.<p>
+<div class="doc_text">
+<p>Constant expressions are used to allow expressions involving other constants
+to be used as constants. Constant expressions may be of any <a
+href="#t_firstclass">first class</a> type, and may involve any LLVM operation
+that does not have side effects (e.g. load and call are not supported). The
+following is the syntax for constant expressions:</p>
+<dl>
+ <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="functionstructure">Functions
-</b></font></td></tr></table><ul>
+ <dd>Cast a constant to another type.</dd>
-LLVM functions definitions are composed of a (possibly empty) argument list, an
-opening curly brace, a list of basic blocks, and a closing curly brace. LLVM
-function declarations are defined with the "<tt>declare</tt>" keyword, a
-function name and a function signature.<p>
+ <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
-A function definition contains a list of basic blocks, forming the CFG for the
-function. Each basic block may optionally start with a label (giving the basic
-block a symbol table entry), contains a list of instructions, and ends with a <a
-href="#terminators">terminator</a> instruction (such as a branch or function
-return).<p>
+ <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
+ constants. As with the <a href="#i_getelementptr">getelementptr</a>
+ instruction, the index list may have zero or more indexes, which are required
+ to make sense for the type of "CSTPTR".</dd>
-The first basic block in program is special in two ways: it is immediately
-executed on entrance to the function, and it is not allowed to have predecessor
-basic blocks (i.e. there can not be any branches to the entry block of a
-function). Because the block can have no predecessors, it also cannot have any
-<a href="#i_phi">PHI nodes</a>.<p>
+ <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
+ <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
+ be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
+ binary</a> operations. The constraints on operands are the same as those for
+ the corresponding instruction (e.g. no bitwise operations on floating point
+ are allowed).</dd>
+</dl>
+</div>
<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
-<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="instref">Instruction Reference
-</b></font></td></tr></table><ul>
+<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
<!-- *********************************************************************** -->
-The LLVM instruction set consists of several different classifications of
-instructions: <a href="#terminators">terminator instructions</a>, <a
-href="#binaryops">binary instructions</a>, <a href="#memoryops">memory
-instructions</a>, and <a href="#otherops">other instructions</a>.<p>
+<div class="doc_text">
+<p>The LLVM instruction set consists of several different
+classifications of instructions: <a href="#terminators">terminator
+instructions</a>, <a href="#binaryops">binary instructions</a>, <a
+ href="#memoryops">memory instructions</a>, and <a href="#otherops">other
+instructions</a>.</p>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="terminators">Terminator Instructions
-</b></font></td></tr></table><ul>
-
-As mentioned <a href="#functionstructure">previously</a>, every basic block in a
-program ends with a "Terminator" instruction, which indicates which block should
-be executed after the current block is finished. These terminator instructions
-typically yield a '<tt>void</tt>' value: they produce control flow, not values
-(the one exception being the '<a href="#i_invoke"><tt>invoke</tt></a>'
-instruction).<p>
-
-There are five different terminator instructions: the '<a
-href="#i_ret"><tt>ret</tt></a>' instruction, the '<a
-href="#i_br"><tt>br</tt></a>' instruction, the '<a
-href="#i_switch"><tt>switch</tt></a>' instruction, the '<a
-href="#i_invoke"><tt>invoke</tt></a>' instruction, and the '<a
-href="#i_unwind"><tt>unwind</tt></a>' instruction.<p>
+</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="terminators">Terminator
+Instructions</a> </div>
+
+<div class="doc_text">
+
+<p>As mentioned <a href="#functionstructure">previously</a>, every
+basic block in a program ends with a "Terminator" instruction, which
+indicates which block should be executed after the current block is
+finished. These terminator instructions typically yield a '<tt>void</tt>'
+value: they produce control flow, not values (the one exception being
+the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
+<p>There are six different terminator instructions: the '<a
+ href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
+instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
+the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
+ href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
+ href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
+
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_ret"><h4><hr size=0>'<tt>ret</tt>' Instruction</h4><ul>
-
+<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
+Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- ret <type> <value> <i>; Return a value from a non-void function</i>
+<pre> ret <type> <value> <i>; Return a value from a non-void function</i>
ret void <i>; Return from void function</i>
</pre>
-
<h5>Overview:</h5>
-
-The '<tt>ret</tt>' instruction is used to return control flow (and a value) from
-a function, back to the caller.<p>
-
-There are two forms of the '<tt>ret</tt>' instructruction: one that returns a
-value and then causes control flow, and one that just causes control flow to
-occur.<p>
-
+<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
+value) from a function, back to the caller.</p>
+<p>There are two forms of the '<tt>ret</tt>' instruction: one that
+returns a value and then causes control flow, and one that just causes
+control flow to occur.</p>
<h5>Arguments:</h5>
-
-The '<tt>ret</tt>' instruction may return any '<a href="#t_firstclass">first
-class</a>' type. Notice that a function is not <a href="#wellformed">well
-formed</a> if there exists a '<tt>ret</tt>' instruction inside of the function
-that returns a value that does not match the return type of the function.<p>
-
+<p>The '<tt>ret</tt>' instruction may return any '<a
+ href="#t_firstclass">first class</a>' type. Notice that a function is
+not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
+instruction inside of the function that returns a value that does not
+match the return type of the function.</p>
<h5>Semantics:</h5>
-
-When the '<tt>ret</tt>' instruction is executed, control flow returns back to
-the calling function's context. If the caller is a "<a
-href="#i_call"><tt>call</tt></a> instruction, execution continues at the
-instruction after the call. If the caller was an "<a
-href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at the
-beginning "normal" of the destination block. If the instruction returns a
-value, that value shall set the call or invoke instruction's return value.<p>
-
-
+<p>When the '<tt>ret</tt>' instruction is executed, control flow
+returns back to the calling function's context. If the caller is a "<a
+ href="#i_call"><tt>call</tt></a>" instruction, execution continues at
+the instruction after the call. If the caller was an "<a
+ href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
+at the beginning "normal" of the destination block. If the instruction
+returns a value, that value shall set the call or invoke instruction's
+return value.</p>
<h5>Example:</h5>
-<pre>
- ret int 5 <i>; Return an integer value of 5</i>
+<pre> ret int 5 <i>; Return an integer value of 5</i>
ret void <i>; Return from a void function</i>
</pre>
-
-
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_br"><h4><hr size=0>'<tt>br</tt>' Instruction</h4><ul>
-
+<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- br bool <cond>, label <iftrue>, label <iffalse>
- br label <dest> <i>; Unconditional branch</i>
+<pre> br bool <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i>
</pre>
-
<h5>Overview:</h5>
-
-The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
-different basic block in the current function. There are two forms of this
-instruction, corresponding to a conditional branch and an unconditional
-branch.<p>
-
+<p>The '<tt>br</tt>' instruction is used to cause control flow to
+transfer to a different basic block in the current function. There are
+two forms of this instruction, corresponding to a conditional branch
+and an unconditional branch.</p>
<h5>Arguments:</h5>
-
-The conditional branch form of the '<tt>br</tt>' instruction takes a single
-'<tt>bool</tt>' value and two '<tt>label</tt>' values. The unconditional form
-of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
-target.<p>
-
+<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
+single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
+unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
+value as a target.</p>
<h5>Semantics:</h5>
-
-Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
-argument is evaluated. If the value is <tt>true</tt>, control flows to the
-'<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
-control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.<p>
-
+<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
+argument is evaluated. If the value is <tt>true</tt>, control flows
+to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
+control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
<h5>Example:</h5>
-<pre>
-Test:
- %cond = <a href="#i_setcc">seteq</a> int %a, %b
- br bool %cond, label %IfEqual, label %IfUnequal
-IfEqual:
- <a href="#i_ret">ret</a> int 1
-IfUnequal:
- <a href="#i_ret">ret</a> int 0
-</pre>
-
-
+<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
+ href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_switch"><h4><hr size=0>'<tt>switch</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_switch">'<tt>switch</tt>' Instruction</a>
+</div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- switch uint <value>, label <defaultdest> [ int <val>, label &dest>, ... ]
+<pre>
+ switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ]
</pre>
<h5>Overview:</h5>
-The '<tt>switch</tt>' instruction is used to transfer control flow to one of
+<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
several different places. It is a generalization of the '<tt>br</tt>'
-instruction, allowing a branch to occur to one of many possible destinations.<p>
+instruction, allowing a branch to occur to one of many possible
+destinations.</p>
+
<h5>Arguments:</h5>
-The '<tt>switch</tt>' instruction uses three parameters: a '<tt>uint</tt>'
+<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
-an array of pairs of comparison value constants and '<tt>label</tt>'s.<p>
+an array of pairs of comparison value constants and '<tt>label</tt>'s. The
+table is not allowed to contain duplicate constant entries.</p>
<h5>Semantics:</h5>
-The <tt>switch</tt> instruction specifies a table of values and destinations.
-When the '<tt>switch</tt>' instruction is executed, this table is searched for
-the given value. If the value is found, the corresponding destination is
-branched to, otherwise the default value it transfered to.<p>
+<p>The <tt>switch</tt> instruction specifies a table of values and
+destinations. When the '<tt>switch</tt>' instruction is executed, this
+table is searched for the given value. If the value is found, control flow is
+transfered to the corresponding destination; otherwise, control flow is
+transfered to the default destination.</p>
<h5>Implementation:</h5>
-Depending on properties of the target machine and the particular <tt>switch</tt>
-instruction, this instruction may be code generated as a series of chained
-conditional branches, or with a lookup table.<p>
+<p>Depending on properties of the target machine and the particular
+<tt>switch</tt> instruction, this instruction may be code generated in different
+ways. For example, it could be generated as a series of chained conditional
+branches or with a lookup table.</p>
<h5>Example:</h5>
+
<pre>
- <i>; Emulate a conditional br instruction</i>
- %Val = <a href="#i_cast">cast</a> bool %value to uint
- switch uint %Val, label %truedest [int 0, label %falsedest ]
+ <i>; Emulate a conditional br instruction</i>
+ %Val = <a href="#i_cast">cast</a> bool %value to int
+ switch int %Val, label %truedest [int 0, label %falsedest ]
- <i>; Emulate an unconditional br instruction</i>
- switch uint 0, label %dest [ ]
+ <i>; Emulate an unconditional br instruction</i>
+ switch uint 0, label %dest [ ]
- <i>; Implement a jump table:</i>
- switch uint %val, label %otherwise [ int 0, label %onzero,
- int 1, label %onone,
- int 2, label %ontwo ]
+ <i>; Implement a jump table:</i>
+ switch uint %val, label %otherwise [ uint 0, label %onzero
+ uint 1, label %onone
+ uint 2, label %ontwo ]
</pre>
-
-
-
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_invoke"><h4><hr size=0>'<tt>invoke</tt>' Instruction</h4><ul>
-
+<div class="doc_subsubsection"> <a name="i_invoke">'<tt>invoke</tt>'
+Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- <result> = invoke <ptr to function ty> %<function ptr val>(<function args>)
- to label <normal label> except label <exception label>
-</pre>
-
+<pre> <result> = invoke <ptr to function ty> %<function ptr val>(<function args>)<br> to label <normal label> except label <exception label><br></pre>
<h5>Overview:</h5>
-
-The '<tt>invoke</tt>' instruction causes control to transfer to a specified
-function, with the possibility of control flow transfer to either the
-'<tt>normal</tt>' <tt>label</tt> label or the '<tt>exception</tt>'
-<tt>label</tt>. If the callee function returns with the "<tt><a
-href="#i_ret">ret</a></tt>" instruction, control flow will return to the
-"normal" label. If the callee (or any indirect callees) returns with the "<a
-href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted, and
-continued at the dynamically nearest "except" label.<p>
-
-
+<p>The '<tt>invoke</tt>' instruction causes control to transfer to a
+specified function, with the possibility of control flow transfer to
+either the '<tt>normal</tt>' <tt>label</tt> label or the '<tt>exception</tt>'<tt>label</tt>.
+If the callee function returns with the "<tt><a href="#i_ret">ret</a></tt>"
+instruction, control flow will return to the "normal" label. If the
+callee (or any indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
+instruction, control is interrupted, and continued at the dynamically
+nearest "except" label.</p>
<h5>Arguments:</h5>
-
-This instruction requires several arguments:<p>
+<p>This instruction requires several arguments:</p>
<ol>
-
-<li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
-function value being invoked. In most cases, this is a direct function
-invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
-an arbitrary pointer to function value.
-
-<li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
-function to be invoked.
-
-<li>'<tt>function args</tt>': argument list whose types match the function
-signature argument types. If the function signature indicates the function
-accepts a variable number of arguments, the extra arguments can be specified.
-
-<li>'<tt>normal label</tt>': the label reached when the called function executes
-a '<tt><a href="#i_ret">ret</a></tt>' instruction.
-
-<li>'<tt>exception label</tt>': the label reached when a callee returns with the
-<a href="#i_unwind"><tt>unwind</tt></a> instruction.
+ <li>'<tt>ptr to function ty</tt>': shall be the signature of the
+pointer to function value being invoked. In most cases, this is a
+direct function invocation, but indirect <tt>invoke</tt>s are just as
+possible, branching off an arbitrary pointer to function value. </li>
+ <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer
+to a function to be invoked. </li>
+ <li>'<tt>function args</tt>': argument list whose types match the
+function signature argument types. If the function signature indicates
+the function accepts a variable number of arguments, the extra
+arguments can be specified. </li>
+ <li>'<tt>normal label</tt>': the label reached when the called
+function executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
+ <li>'<tt>exception label</tt>': the label reached when a callee
+returns with the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
</ol>
-
<h5>Semantics:</h5>
-
-This instruction is designed to operate as a standard '<tt><a
-href="#i_call">call</a></tt>' instruction in most regards. The primary
-difference is that it establishes an association with a label, which is used by the runtime library to unwind the stack.<p>
-
-This instruction is used in languages with destructors to ensure that proper
-cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
-exception. Additionally, this is important for implementation of
-'<tt>catch</tt>' clauses in high-level languages that support them.<p>
-
+<p>This instruction is designed to operate as a standard '<tt><a
+ href="#i_call">call</a></tt>' instruction in most regards. The
+primary difference is that it establishes an association with a label,
+which is used by the runtime library to unwind the stack.</p>
+<p>This instruction is used in languages with destructors to ensure
+that proper cleanup is performed in the case of either a <tt>longjmp</tt>
+or a thrown exception. Additionally, this is important for
+implementation of '<tt>catch</tt>' clauses in high-level languages that
+support them.</p>
<h5>Example:</h5>
-<pre>
- %retval = invoke int %Test(int 15)
- to label %Continue
- except label %TestCleanup <i>; {int}:retval set</i>
+<pre> %retval = invoke int %Test(int 15)<br> to label %Continue<br> except label %TestCleanup <i>; {int}:retval set</i>
</pre>
+</div>
+
<!-- _______________________________________________________________________ -->
-</ul><a name="i_unwind"><h4><hr size=0>'<tt>unwind</tt>' Instruction</h4><ul>
+
+<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
+Instruction</a> </div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
<h5>Overview:</h5>
-The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow at
-the first callee in the dynamic call stack which used an <a
+<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
+
at the first callee in the dynamic call stack which used an <a
href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
-primarily used to implement exception handling.
+primarily used to implement exception handling.</p>
<h5>Semantics:</h5>
-The '<tt>unwind</tt>' intrinsic causes execution of the current function to
+<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
immediately halt. The dynamic call stack is then searched for the first <a
href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
execution continues at the "exceptional" destination block specified by the
<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
-dynamic call chain, undefined behavior results.
+dynamic call chain, undefined behavior results.</p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
+Instruction</a> </div>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="binaryops">Binary Operations
-</b></font></td></tr></table><ul>
-
-Binary operators are used to do most of the computation in a program. They
-require two operands, execute an operation on them, and produce a single value.
-The result value of a binary operator is not necessarily the same type as its
-operands.<p>
-
-There are several different binary operators:<p>
-
-
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_add"><h4><hr size=0>'<tt>add</tt>' Instruction</h4><ul>
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = add <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ unreachable
</pre>
<h5>Overview:</h5>
-The '<tt>add</tt>' instruction returns the sum of its two operands.<p>
-<h5>Arguments:</h5>
-The two arguments to the '<tt>add</tt>' instruction must be either <a href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
+<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
+instruction is used to inform the optimizer that a particular portion of the
+code is not reachable. This can be used to indicate that the code after a
+no-return function cannot be reached, and other facts.</p>
<h5>Semantics:</h5>
-The value produced is the integer or floating point sum of the two operands.<p>
+<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
+</div>
-<h5>Example:</h5>
-<pre>
- <result> = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
-</pre>
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
+<div class="doc_text">
+<p>Binary operators are used to do most of the computation in a
+program. They require two operands, execute an operation on them, and
+produce a single value. The operands might represent
+multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
+The result value of a binary operator is not
+necessarily the same type as its operands.</p>
+<p>There are several different binary operators:</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_sub"><h4><hr size=0>'<tt>sub</tt>' Instruction</h4><ul>
-
+<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
+Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- <result> = sub <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+<pre> <result> = add <ty> <var1>, <var2> <i>; yields {ty}:result</i>
</pre>
-
<h5>Overview:</h5>
-
-The '<tt>sub</tt>' instruction returns the difference of its two operands.<p>
-
-Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
-instruction present in most other intermediate representations.<p>
-
+<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
<h5>Arguments:</h5>
-
-The two arguments to the '<tt>sub</tt>' instruction must be either <a
-href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
-values. Both arguments must have identical types.<p>
-
+<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
+ This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
-The value produced is the integer or floating point difference of the two
-operands.<p>
-
+<p>The value produced is the integer or floating point sum of the two
+operands.</p>
<h5>Example:</h5>
-<pre>
- <result> = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
- <result> = sub int 0, %val <i>; yields {int}:result = -%var</i>
+<pre> <result> = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
</pre>
-
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_mul"><h4><hr size=0>'<tt>mul</tt>' Instruction</h4><ul>
-
+<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
+Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- <result> = mul <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+<pre> <result> = sub <ty> <var1>, <var2> <i>; yields {ty}:result</i>
</pre>
-
<h5>Overview:</h5>
-The '<tt>mul</tt>' instruction returns the product of its two operands.<p>
-
+<p>The '<tt>sub</tt>' instruction returns the difference of its two
+operands.</p>
+<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
+instruction present in most other intermediate representations.</p>
<h5>Arguments:</h5>
-The two arguments to the '<tt>mul</tt>' instruction must be either <a href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
-
+<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
+values.
+This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
-The value produced is the integer or floating point product of the two
-operands.<p>
-
-There is no signed vs unsigned multiplication. The appropriate action is taken
-based on the type of the operand. <p>
-
-
+<p>The value produced is the integer or floating point difference of
+the two operands.</p>
<h5>Example:</h5>
-<pre>
- <result> = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
+<pre> <result> = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
+ <result> = sub int 0, %val <i>; yields {int}:result = -%var</i>
</pre>
-
-
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_div"><h4><hr size=0>'<tt>div</tt>' Instruction</h4><ul>
-
+<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
+Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- <result> = div <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+<pre> <result> = mul <ty> <var1>, <var2> <i>; yields {ty}:result</i>
</pre>
-
<h5>Overview:</h5>
-
-The '<tt>div</tt>' instruction returns the quotient of its two operands.<p>
-
+<p>The '<tt>mul</tt>' instruction returns the product of its two
+operands.</p>
<h5>Arguments:</h5>
-
-The two arguments to the '<tt>div</tt>' instruction must be either <a
-href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
-values. Both arguments must have identical types.<p>
-
+<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
+values.
+This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
-The value produced is the integer or floating point quotient of the two
-operands.<p>
-
+<p>The value produced is the integer or floating point product of the
+two operands.</p>
+<p>There is no signed vs unsigned multiplication. The appropriate
+action is taken based on the type of the operand.</p>
<h5>Example:</h5>
-<pre>
- <result> = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
+<pre> <result> = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
</pre>
-
-
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_rem"><h4><hr size=0>'<tt>rem</tt>' Instruction</h4><ul>
-
+<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
+Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- <result> = rem <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+<pre> <result> = div <ty> <var1>, <var2> <i>; yields {ty}:result</i>
</pre>
-
<h5>Overview:</h5>
-The '<tt>rem</tt>' instruction returns the remainder from the division of its two operands.<p>
-
+<p>The '<tt>div</tt>' instruction returns the quotient of its two
+operands.</p>
<h5>Arguments:</h5>
-The two arguments to the '<tt>rem</tt>' instruction must be either <a href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
-
+<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
+values.
+This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
<h5>Semantics:</h5>
-
-This returns the <i>remainder</i> of a division (where the result has the same
-sign as the divisor), not the <i>modulus</i> (where the result has the same sign
-as the dividend) of a value. For more information about the difference, see: <a
-href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The Math
-Forum</a>.<p>
-
+<p>The value produced is the integer or floating point quotient of the
+two operands.</p>
<h5>Example:</h5>
-<pre>
- <result> = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
+<pre> <result> = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
</pre>
-
-
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_setcc"><h4><hr size=0>'<tt>set<i>cc</i></tt>' Instructions</h4><ul>
-
+<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
+Instruction</a> </div>
+<div class="doc_text">
<h5>Syntax:</h5>
-<pre>
- <result> = seteq <ty> <var1>, <var2> <i>; yields {bool}:result</i>
+<pre> <result> = rem <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>rem</tt>' instruction returns the remainder from the
+division of its two operands.</p>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
+ href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
+values.
+This instruction can also take <a href="#t_packed">packed</a> versions of the values.
+Both arguments must have identical types.</p>
+<h5>Semantics:</h5>
+<p>This returns the <i>remainder</i> of a division (where the result
+has the same sign as the divisor), not the <i>modulus</i> (where the
+result has the same sign as the dividend) of a value. For more
+information about the difference, see: <a
+ href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
+Math Forum</a>.</p>
+<h5>Example:</h5>
+<pre> <result> = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
+Instructions</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = seteq <ty> <var1>, <var2> <i>; yields {bool}:result</i>
<result> = setne <ty> <var1>, <var2> <i>; yields {bool}:result</i>
<result> = setlt <ty> <var1>, <var2> <i>; yields {bool}:result</i>
<result> = setgt <ty> <var1>, <var2> <i>; yields {bool}:result</i>
<result> = setle <ty> <var1>, <var2> <i>; yields {bool}:result</i>
<result> = setge <ty> <var1>, <var2> <i>; yields {bool}:result</i>
</pre>
-
-<h5>Overview:</h5> The '<tt>set<i>cc</i></tt>' family of instructions returns a
-boolean value based on a comparison of their two operands.<p>
-
-<h5>Arguments:</h5> The two arguments to the '<tt>set<i>cc</i></tt>'
-instructions must be of <a href="#t_firstclass">first class</a> or <a
-href="#t_pointer">pointer</a> type (it is not possible to compare
-'<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>' or '<tt>void</tt>'
-values, etc...). Both arguments must have identical types.<p>
-
+<h5>Overview:</h5>
+<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
+value based on a comparison of their two operands.</p>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
+be of <a href="#t_firstclass">first class</a> type (it is not possible
+to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
+or '<tt>void</tt>' values, etc...). Both arguments must have identical
+types.</p>
<h5>Semantics:</h5>
-
-The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
-both operands are equal.<br>
-
-The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
-both operands are unequal.<br>
-
-The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
-the first operand is less than the second operand.<br>
-
-The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
-the first operand is greater than the second operand.<br>
-
-The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
-the first operand is less than or equal to the second operand.<br>
-
-The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
-the first operand is greater than or equal to the second operand.<p>
-
+<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if both operands are equal.<br>
+The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if both operands are unequal.<br>
+The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if the first operand is less than the second operand.<br>
+The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if the first operand is greater than the second operand.<br>
+The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if the first operand is less than or equal to the second operand.<br>
+The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
+value if the first operand is greater than or equal to the second
+operand.</p>
<h5>Example:</h5>
-<pre>
- <result> = seteq int 4, 5 <i>; yields {bool}:result = false</i>
+<pre> <result> = seteq int 4, 5 <i>; yields {bool}:result = false</i>
<result> = setne float 4, 5 <i>; yields {bool}:result = true</i>
<result> = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
<result> = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
<result> = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
<result> = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
</pre>
-
-
-
+</div>
<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="bitwiseops">Bitwise Binary Operations
-</b></font></td></tr></table><ul>
-
-Bitwise binary operators are used to do various forms of bit-twiddling in a
-program. They are generally very efficient instructions, and can commonly be
-strength reduced from other instructions. They require two operands, execute an
-operation on them, and produce a single value. The resulting value of the
-bitwise binary operators is always the same type as its first operand.<p>
+<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
+Operations</a> </div>
+<div class="doc_text">
+<p>Bitwise binary operators are used to do various forms of
+bit-twiddling in a program. They are generally very efficient
+instructions and can commonly be strength reduced from other
+instructions. They require two operands, execute an operation on them,
+and produce a single value. The resulting value of the bitwise binary
+operators is always the same type as its first operand.</p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = and <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
+its two operands.</p>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>and</tt>' instruction must be <a
+ href="#t_integral">integral</a> values. Both arguments must have
+identical types.</p>
+<h5>Semantics:</h5>
+<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
+<p> </p>
+<div style="align: center">
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr>
+ <td>In0</td>
+ <td>In1</td>
+ <td>Out</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>0</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>1</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>0</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>1</td>
+ <td>1</td>
+ </tr>
+ </tbody>
+</table>
+</div>
+<h5>Example:</h5>
+<pre> <result> = and int 4, %var <i>; yields {int}:result = 4 & %var</i>
+ <result> = and int 15, 40 <i>; yields {int}:result = 8</i>
+ <result> = and int 4, 8 <i>; yields {int}:result = 0</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = or <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
+or of its two operands.</p>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>or</tt>' instruction must be <a
+ href="#t_integral">integral</a> values. Both arguments must have
+identical types.</p>
+<h5>Semantics:</h5>
+<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
+<p> </p>
+<div style="align: center">
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr>
+ <td>In0</td>
+ <td>In1</td>
+ <td>Out</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>0</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>1</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>0</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>1</td>
+ <td>1</td>
+ </tr>
+ </tbody>
+</table>
+</div>
+<h5>Example:</h5>
+<pre> <result> = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
+ <result> = or int 15, 40 <i>; yields {int}:result = 47</i>
+ <result> = or int 4, 8 <i>; yields {int}:result = 12</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = xor <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
+or of its two operands. The <tt>xor</tt> is used to implement the
+"one's complement" operation, which is the "~" operator in C.</p>
+<h5>Arguments:</h5>
+<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
+ href="#t_integral">integral</a> values. Both arguments must have
+identical types.</p>
+<h5>Semantics:</h5>
+<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
+<p> </p>
+<div style="align: center">
+<table border="1" cellspacing="0" cellpadding="4">
+ <tbody>
+ <tr>
+ <td>In0</td>
+ <td>In1</td>
+ <td>Out</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>0</td>
+ <td>0</td>
+ </tr>
+ <tr>
+ <td>0</td>
+ <td>1</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>0</td>
+ <td>1</td>
+ </tr>
+ <tr>
+ <td>1</td>
+ <td>1</td>
+ <td>0</td>
+ </tr>
+ </tbody>
+</table>
+</div>
+<p> </p>
+<h5>Example:</h5>
+<pre> <result> = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
+ <result> = xor int 15, 40 <i>; yields {int}:result = 39</i>
+ <result> = xor int 4, 8 <i>; yields {int}:result = 12</i>
+ <result> = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = shl <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
+the left a specified number of bits.</p>
+<h5>Arguments:</h5>
+<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
+ href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
+type.</p>
+<h5>Semantics:</h5>
+<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
+<h5>Example:</h5>
+<pre> <result> = shl int 4, ubyte %var <i>; yields {int}:result = 4 << %var</i>
+ <result> = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
+ <result> = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = shr <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
+the right a specified number of bits.</p>
+<h5>Arguments:</h5>
+<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
+ href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
+type.</p>
+<h5>Semantics:</h5>
+<p>If the first argument is a <a href="#t_signed">signed</a> type, the
+most significant bit is duplicated in the newly free'd bit positions.
+If the first argument is unsigned, zero bits shall fill the empty
+positions.</p>
+<h5>Example:</h5>
+<pre> <result> = shr int 4, ubyte %var <i>; yields {int}:result = 4 >> %var</i>
+ <result> = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
+ <result> = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
+ <result> = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
+ <result> = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
+</pre>
+</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="memoryops">Memory Access
+Operations</a></div>
+<div class="doc_text">
+<p>A key design point of an SSA-based representation is how it
+represents memory. In LLVM, no memory locations are in SSA form, which
+makes things very simple. This section describes how to read, write,
+allocate, and free memory in LLVM.</p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_malloc">'<tt>malloc</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = malloc <type>, uint <NumElements> <i>; yields {type*}:result</i>
+ <result> = malloc <type> <i>; yields {type*}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>malloc</tt>' instruction allocates memory from the system
+heap and returns a pointer to it.</p>
+<h5>Arguments:</h5>
+<p>The '<tt>malloc</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt>
+bytes of memory from the operating system and returns a pointer of the
+appropriate type to the program. The second form of the instruction is
+a shorter version of the first instruction that defaults to allocating
+one element.</p>
+<p>'<tt>type</tt>' must be a sized type.</p>
+<h5>Semantics:</h5>
+<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
+a pointer is returned.</p>
+<h5>Example:</h5>
+<pre> %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
+ %size = <a
+ href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
+ %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
+ %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_free">'<tt>free</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> free <type> <value> <i>; yields {void}</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>free</tt>' instruction returns memory back to the unused
+memory heap, to be reallocated in the future.</p>
+<p> </p>
+<h5>Arguments:</h5>
+<p>'<tt>value</tt>' shall be a pointer value that points to a value
+that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
+instruction.</p>
+<h5>Semantics:</h5>
+<p>Access to the memory pointed to by the pointer is no longer defined
+after this instruction executes.</p>
+<h5>Example:</h5>
+<pre> %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
+ free [4 x ubyte]* %array
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_alloca">'<tt>alloca</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = alloca <type>, uint <NumElements> <i>; yields {type*}:result</i>
+ <result> = alloca <type> <i>; yields {type*}:result</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>alloca</tt>' instruction allocates memory on the current
+stack frame of the procedure that is live until the current function
+returns to its caller.</p>
+<h5>Arguments:</h5>
+<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(<type>)*NumElements</tt>
+bytes of memory on the runtime stack, returning a pointer of the
+appropriate type to the program. The second form of the instruction is
+a shorter version of the first that defaults to allocating one element.</p>
+<p>'<tt>type</tt>' may be any sized type.</p>
+<h5>Semantics:</h5>
+<p>Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d
+memory is automatically released when the function returns. The '<tt>alloca</tt>'
+instruction is commonly used to represent automatic variables that must
+have an address available. When the function returns (either with the <tt><a
+ href="#i_ret">ret</a></tt> or <tt><a href="#i_invoke">invoke</a></tt>
+instructions), the memory is reclaimed.</p>
+<h5>Example:</h5>
+<pre> %ptr = alloca int <i>; yields {int*}:ptr</i>
+ %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = load <ty>* <pointer><br> <result> = volatile load <ty>* <pointer><br></pre>
+<h5>Overview:</h5>
+<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
+<h5>Arguments:</h5>
+<p>The argument to the '<tt>load</tt>' instruction specifies the memory
+address to load from. The pointer must point to a <a
+ href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
+marked as <tt>volatile</tt> then the optimizer is not allowed to modify
+the number or order of execution of this <tt>load</tt> with other
+volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
+instructions. </p>
+<h5>Semantics:</h5>
+<p>The location of memory pointed to is loaded.</p>
+<h5>Examples:</h5>
+<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
+ <a
+ href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
+ %val = load int* %ptr <i>; yields {int}:val = int 3</i>
+</pre>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
+Instruction</a> </div>
+<h5>Syntax:</h5>
+<pre> store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i>
+ volatile store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i>
+</pre>
+<h5>Overview:</h5>
+<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
+<h5>Arguments:</h5>
+<p>There are two arguments to the '<tt>store</tt>' instruction: a value
+to store and an address to store it into. The type of the '<tt><pointer></tt>'
+operand must be a pointer to the type of the '<tt><value></tt>'
+operand. If the <tt>store</tt> is marked as <tt>volatile</tt> then the
+optimizer is not allowed to modify the number or order of execution of
+this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
+ href="#i_store">store</a></tt> instructions.</p>
+<h5>Semantics:</h5>
+<p>The contents of memory are updated to contain '<tt><value></tt>'
+at the location specified by the '<tt><pointer></tt>' operand.</p>
+<h5>Example:</h5>
+<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
+ <a
+ href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
+ %val = load int* %ptr <i>; yields {int}:val = int 3</i>
+</pre>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_and"><h4><hr size=0>'<tt>and</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
+</div>
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = and <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ <result> = getelementptr <ty>* <ptrval>{, <ty> <idx>}*
</pre>
<h5>Overview:</h5>
-The '<tt>and</tt>' instruction returns the bitwise logical and of its two operands.<p>
+
+<p>
+The '<tt>getelementptr</tt>' instruction is used to get the address of a
+subelement of an aggregate data structure.</p>
<h5>Arguments:</h5>
-The two arguments to the '<tt>and</tt>' instruction must be <a
-href="#t_integral">integral</a> values. Both arguments must have identical
-types.<p>
+<p>This instruction takes a list of integer constants that indicate what
+elements of the aggregate object to index to. The actual types of the arguments
+provided depend on the type of the first pointer argument. The
+'<tt>getelementptr</tt>' instruction is used to index down through the type
+levels of a structure. When indexing into a structure, only <tt>uint</tt>
+integer constants are allowed. When indexing into an array or pointer
+<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
+<p>For example, let's consider a C code fragment and how it gets
+compiled to LLVM:</p>
-<h5>Semantics:</h5>
+<pre>
+ struct RT {
+ char A;
+ int B[10][20];
+ char C;
+ };
+ struct ST {
+ int X;
+ double Y;
+ struct RT Z;
+ };
-The truth table used for the '<tt>and</tt>' instruction is:<p>
+ int *foo(struct ST *s) {
+ return &s[1].Z.B[5][13];
+ }
+</pre>
+
+<p>The LLVM code generated by the GCC frontend is:</p>
-<center><table border=1 cellspacing=0 cellpadding=4>
-<tr><td>In0</td> <td>In1</td> <td>Out</td></tr>
-<tr><td>0</td> <td>0</td> <td>0</td></tr>
-<tr><td>0</td> <td>1</td> <td>0</td></tr>
-<tr><td>1</td> <td>0</td> <td>0</td></tr>
-<tr><td>1</td> <td>1</td> <td>1</td></tr>
-</table></center><p>
+<pre>
+ %RT = type { sbyte, [10 x [20 x int]], sbyte }
+ %ST = type { int, double, %RT }
+ implementation
+
+ int* %foo(%ST* %s) {
+ entry:
+ %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
+ ret int* %reg
+ }
+</pre>
+<h5>Semantics:</h5>
+
+<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
+on the pointer type that is being index into. <a href="#t_pointer">Pointer</a>
+and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
+<tt>ulong</tt>, or <tt>long</tt> values, and <a href="#t_struct">structure</a>
+types require <tt>uint</tt> <b>constants</b>.</p>
+
+<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
+type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
+}</tt>' type, a structure. The second index indexes into the third element of
+the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
+sbyte }</tt>' type, another structure. The third index indexes into the second
+element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
+array. The two dimensions of the array are subscripted into, yielding an
+'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer
+to this element, thus computing a value of '<tt>int*</tt>' type.</p>
+
+<p>Note that it is perfectly legal to index partially through a
+structure, returning a pointer to an inner element. Because of this,
+the LLVM code for the given testcase is equivalent to:</p>
+
+<pre>
+ int* "foo"(%ST* %s) {
+ %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
+ %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
+ %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
+ %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
+ %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
+ ret int* %t5
+ }
+</pre>
<h5>Example:</h5>
<pre>
- <result> = and int 4, %var <i>; yields {int}:result = 4 & %var</i>
- <result> = and int 15, 40 <i>; yields {int}:result = 8</i>
- <result> = and int 4, 8 <i>; yields {int}:result = 0</i>
+ <i>; yields [12 x ubyte]*:aptr</i>
+ %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
</pre>
-
+</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
+<div class="doc_text">
+<p>The instructions in this category are the "miscellaneous"
+instructions, which defy better classification.</p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = phi <ty> [ <val0>, <label0>], ...<br></pre>
+<h5>Overview:</h5>
+<p>The '<tt>phi</tt>' instruction is used to implement the φ node in
+the SSA graph representing the function.</p>
+<h5>Arguments:</h5>
+<p>The type of the incoming values are specified with the first type
+field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
+as arguments, with one pair for each predecessor basic block of the
+current block. Only values of <a href="#t_firstclass">first class</a>
+type may be used as the value arguments to the PHI node. Only labels
+may be used as the label arguments.</p>
+<p>There must be no non-phi instructions between the start of a basic
+block and the PHI instructions: i.e. PHI instructions must be first in
+a basic block.</p>
+<h5>Semantics:</h5>
+<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
+value specified by the parameter, depending on which basic block we
+came from in the last <a href="#terminators">terminator</a> instruction.</p>
+<h5>Example:</h5>
+<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_or"><h4><hr size=0>'<tt>or</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = or <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ <result> = cast <ty> <value> to <ty2> <i>; yields ty2</i>
</pre>
-<h5>Overview:</h5> The '<tt>or</tt>' instruction returns the bitwise logical
-inclusive or of its two operands.<p>
+<h5>Overview:</h5>
-<h5>Arguments:</h5>
+<p>
+The '<tt>cast</tt>' instruction is used as the primitive means to convert
+integers to floating point, change data type sizes, and break type safety (by
+casting pointers).
+</p>
-The two arguments to the '<tt>or</tt>' instruction must be <a
-href="#t_integral">integral</a> values. Both arguments must have identical
-types.<p>
+<h5>Arguments:</h5>
+
+<p>
+The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
+class value, and a type to cast it to, which must also be a <a
+href="#t_firstclass">first class</a> type.
+</p>
<h5>Semantics:</h5>
-The truth table used for the '<tt>or</tt>' instruction is:<p>
+<p>
+This instruction follows the C rules for explicit casts when determining how the
+data being cast must change to fit in its new container.
+</p>
-<center><table border=1 cellspacing=0 cellpadding=4>
-<tr><td>In0</td> <td>In1</td> <td>Out</td></tr>
-<tr><td>0</td> <td>0</td> <td>0</td></tr>
-<tr><td>0</td> <td>1</td> <td>1</td></tr>
-<tr><td>1</td> <td>0</td> <td>1</td></tr>
-<tr><td>1</td> <td>1</td> <td>1</td></tr>
-</table></center><p>
+<p>
+When casting to bool, any value that would be considered true in the context of
+a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
+all else are '<tt>false</tt>'.
+</p>
+<p>
+When extending an integral value from a type of one signness to another (for
+example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
+<b>source</b> value is signed, and zero-extended if the source value is
+unsigned. <tt>bool</tt> values are always zero extended into either zero or
+one.
+</p>
<h5>Example:</h5>
+
<pre>
- <result> = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
- <result> = or int 15, 40 <i>; yields {int}:result = 47</i>
- <result> = or int 4, 8 <i>; yields {int}:result = 12</i>
+ %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
+ %Y = cast int 123 to bool <i>; yields bool:true</i>
</pre>
-
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_xor"><h4><hr size=0>'<tt>xor</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_select">'<tt>select</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = xor <ty> <var1>, <var2> <i>; yields {ty}:result</i>
+ <result> = select bool <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i>
</pre>
<h5>Overview:</h5>
-The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of its
-two operands. The <tt>xor</tt> is used to implement the "one's complement"
-operation, which is the "~" operator in C.<p>
+<p>
+The '<tt>select</tt>' instruction is used to choose one value based on a
+condition, without branching.
+</p>
-<h5>Arguments:</h5>
-The two arguments to the '<tt>xor</tt>' instruction must be <a
-href="#t_integral">integral</a> values. Both arguments must have identical
-types.<p>
+<h5>Arguments:</h5>
+<p>
+The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
+</p>
<h5>Semantics:</h5>
-The truth table used for the '<tt>xor</tt>' instruction is:<p>
-
-<center><table border=1 cellspacing=0 cellpadding=4>
-<tr><td>In0</td> <td>In1</td> <td>Out</td></tr>
-<tr><td>0</td> <td>0</td> <td>0</td></tr>
-<tr><td>0</td> <td>1</td> <td>1</td></tr>
-<tr><td>1</td> <td>0</td> <td>1</td></tr>
-<tr><td>1</td> <td>1</td> <td>0</td></tr>
-</table></center><p>
-
+<p>
+If the boolean condition evaluates to true, the instruction returns the first
+value argument, otherwise it returns the second value argument.
+</p>
<h5>Example:</h5>
+
<pre>
- <result> = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
- <result> = xor int 15, 40 <i>; yields {int}:result = 39</i>
- <result> = xor int 4, 8 <i>; yields {int}:result = 12</i>
- <result> = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
+ %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
</pre>
+</div>
+
+
+
<!-- _______________________________________________________________________ -->
-</ul><a name="i_shl"><h4><hr size=0>'<tt>shl</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection"> <a name="i_call">'<tt>call</tt>'
+Instruction</a> </div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> <result> = call <ty>* <fnptrval>(<param list>)<br></pre>
+<h5>Overview:</h5>
+<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
+<h5>Arguments:</h5>
+<p>This instruction requires several arguments:</p>
+<ol>
+ <li>
+ <p>'<tt>ty</tt>': shall be the signature of the pointer to function
+value being invoked. The argument types must match the types implied
+by this signature.</p>
+ </li>
+ <li>
+ <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a
+function to be invoked. In most cases, this is a direct function
+invocation, but indirect <tt>call</tt>s are just as possible,
+calling an arbitrary pointer to function values.</p>
+ </li>
+ <li>
+ <p>'<tt>function args</tt>': argument list whose types match the
+function signature argument types. If the function signature
+indicates the function accepts a variable number of arguments, the
+extra arguments can be specified.</p>
+ </li>
+</ol>
+<h5>Semantics:</h5>
+<p>The '<tt>call</tt>' instruction is used to cause control flow to
+transfer to a specified function, with its incoming arguments bound to
+the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
+instruction in the called function, control flow continues with the
+instruction after the function call, and the return value of the
+function is bound to the result argument. This is a simpler case of
+the <a href="#i_invoke">invoke</a> instruction.</p>
+<h5>Example:</h5>
+<pre> %retval = call int %test(int %argc)<br> call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);<br></pre>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_vanext">'<tt>vanext</tt>' Instruction</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = shl <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i>
+ <resultarglist> = vanext <va_list> <arglist>, <argty>
</pre>
<h5>Overview:</h5>
-The '<tt>shl</tt>' instruction returns the first operand shifted to the left a
-specified number of bits.
+<p>The '<tt>vanext</tt>' instruction is used to access arguments passed
+through the "variable argument" area of a function call. It is used to
+implement the <tt>va_arg</tt> macro in C.</p>
<h5>Arguments:</h5>
-The first argument to the '<tt>shl</tt>' instruction must be an <a
-href="#t_integer">integer</a> type. The second argument must be an
-'<tt>ubyte</tt>' type.<p>
+<p>This instruction takes a <tt>va_list</tt> value and the type of the
+argument. It returns another <tt>va_list</tt>. The actual type of
+<tt>va_list</tt> may be defined differently for different targets. Most targets
+use a <tt>va_list</tt> type of <tt>sbyte*</tt> or some other pointer type.</p>
<h5>Semantics:</h5>
-The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.<p>
+<p>The '<tt>vanext</tt>' instruction advances the specified <tt>va_list</tt>
+past an argument of the specified type. In conjunction with the <a
+ href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement
+the <tt>va_arg</tt> macro available in C. For more information, see
+the variable argument handling <a href="#int_varargs">Intrinsic
+Functions</a>.</p>
+<p>It is legal for this instruction to be called in a function which
+does not take a variable number of arguments, for example, the <tt>vfprintf</tt>
+function.</p>
+
+<p><tt>vanext</tt> is an LLVM instruction instead of an <a
+href="#intrinsics">intrinsic function</a> because it takes a type as an
+argument. The type refers to the current argument in the <tt>va_list</tt>, it
+tells the compiler how far on the stack it needs to advance to find the next
+argument</p>
<h5>Example:</h5>
-<pre>
- <result> = shl int 4, ubyte %var <i>; yields {int}:result = 4 << %var</i>
- <result> = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
- <result> = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
-</pre>
+<p>See the <a href="#int_varargs">variable argument processing</a>
+section.</p>
+
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_shr"><h4><hr size=0>'<tt>shr</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a>
+</div>
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = shr <ty> <var1>, ubyte <var2> <i>; yields {ty}:result</i>
+ <resultval> = vaarg <va_list> <arglist>, <argty>
</pre>
<h5>Overview:</h5>
-The '<tt>shr</tt>' instruction returns the first operand shifted to the right a specified number of bits.
-<h5>Arguments:</h5>
-The first argument to the '<tt>shr</tt>' instruction must be an <a href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>' type.<p>
-
-<h5>Semantics:</h5>
+<p>The '<tt>vaarg</tt>' instruction is used to access arguments passed through
+the "variable argument" area of a function call. It is used to implement the
+<tt>va_arg</tt> macro in C.</p>
-If the first argument is a <a href="#t_signed">signed</a> type, the most
-significant bit is duplicated in the newly free'd bit positions. If the first
-argument is unsigned, zero bits shall fill the empty positions.<p>
+<h5>Arguments:</h5>
-<h5>Example:</h5>
-<pre>
- <result> = shr int 4, ubyte %var <i>; yields {int}:result = 4 >> %var</i>
- <result> = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
- <result> = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
- <result> = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
- <result> = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
-</pre>
+<p>This instruction takes a <tt>va_list</tt> value and the type of the
+argument. It returns a value of the specified argument type. Again, the actual
+type of <tt>va_list</tt> is target specific.</p>
+<h5>Semantics:</h5>
+<p>The '<tt>vaarg</tt>' instruction loads an argument of the specified type from
+the specified <tt>va_list</tt>. In conjunction with the <a
+href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to implement the
+<tt>va_arg</tt> macro available in C. For more information, see the variable
+argument handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
+<p>It is legal for this instruction to be called in a function which does not
+take a variable number of arguments, for example, the <tt>vfprintf</tt>
+function.</p>
+<p><tt>vaarg</tt> is an LLVM instruction instead of an <a
+href="#intrinsics">intrinsic function</a> because it takes an type as an
+argument.</p>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="memoryops">Memory Access Operations
-</b></font></td></tr></table><ul>
+<h5>Example:</h5>
-A key design point of an SSA-based representation is how it represents memory.
-In LLVM, no memory locations are in SSA form, which makes things very simple.
-This section describes how to read, write, allocate and free memory in LLVM.<p>
+<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
+</div>
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_malloc"><h4><hr size=0>'<tt>malloc</tt>' Instruction</h4><ul>
+<!-- *********************************************************************** -->
+<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
+<!-- *********************************************************************** -->
-<h5>Syntax:</h5>
-<pre>
- <result> = malloc <type>, uint <NumElements> <i>; yields {type*}:result</i>
- <result> = malloc <type> <i>; yields {type*}:result</i>
-</pre>
+<div class="doc_text">
-<h5>Overview:</h5>
-The '<tt>malloc</tt>' instruction allocates memory from the system heap and returns a pointer to it.<p>
+<p>LLVM supports the notion of an "intrinsic function". These functions have
+well known names and semantics, and are required to follow certain
+restrictions. Overall, these instructions represent an extension mechanism for
+the LLVM language that does not require changing all of the transformations in
+LLVM to add to the language (or the bytecode reader/writer, the parser,
+etc...).</p>
-<h5>Arguments:</h5>
+<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix, this
+prefix is reserved in LLVM for intrinsic names, thus functions may not be named
+this. Intrinsic functions must always be external functions: you cannot define
+the body of intrinsic functions. Intrinsic functions may only be used in call
+or invoke instructions: it is illegal to take the address of an intrinsic
+function. Additionally, because intrinsic functions are part of the LLVM
+language, it is required that they all be documented here if any are added.</p>
-The the '<tt>malloc</tt>' instruction allocates
-<tt>sizeof(<type>)*NumElements</tt> bytes of memory from the operating
-system, and returns a pointer of the appropriate type to the program. The
-second form of the instruction is a shorter version of the first instruction
-that defaults to allocating one element.<p>
-'<tt>type</tt>' must be a sized type.<p>
+<p>
+Adding an intrinsic to LLVM is straight-forward if it is possible to express the
+concept in LLVM directly (ie, code generator support is not _required_). To do
+this, extend the default implementation of the IntrinsicLowering class to handle
+the intrinsic. Code generators use this class to lower intrinsics they do not
+understand to raw LLVM instructions that they do.
+</p>
-<h5>Semantics:</h5>
+</div>
-Memory is allocated using the system "<tt>malloc</tt>" function, and a pointer
-is returned.<p>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_varargs">Variable Argument Handling Intrinsics</a>
+</div>
-<h5>Example:</h5>
-<pre>
- %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
+<div class="doc_text">
- %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
- %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
- %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
-</pre>
+<p>Variable argument support is defined in LLVM with the <a
+ href="#i_vanext"><tt>vanext</tt></a> instruction and these three
+intrinsic functions. These functions are related to the similarly
+named macros defined in the <tt><stdarg.h></tt> header file.</p>
+<p>All of these functions operate on arguments that use a
+target-specific value type "<tt>va_list</tt>". The LLVM assembly
+language reference manual does not define what this type is, so all
+transformations should be prepared to handle intrinsics with any type
+used.</p>
-<!-- _______________________________________________________________________ -->
-</ul><a name="i_free"><h4><hr size=0>'<tt>free</tt>' Instruction</h4><ul>
+<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
+instruction and the variable argument handling intrinsic functions are
+used.</p>
-<h5>Syntax:</h5>
<pre>
- free <type> <value> <i>; yields {void}</i>
-</pre>
+int %test(int %X, ...) {
+ ; Initialize variable argument processing
+ %ap = call sbyte* %<a href="#i_va_start">llvm.va_start</a>()
+ ; Read a single integer argument
+ %tmp = vaarg sbyte* %ap, int
-<h5>Overview:</h5>
-The '<tt>free</tt>' instruction returns memory back to the unused memory heap, to be reallocated in the future.<p>
+ ; Advance to the next argument
+ %ap2 = vanext sbyte* %ap, int
+ ; Demonstrate usage of llvm.va_copy and llvm.va_end
+ %aq = call sbyte* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2)
+ call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq)
-<h5>Arguments:</h5>
+ ; Stop processing of arguments.
+ call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2)
+ ret int %tmp
+}
+</pre>
+</div>
-'<tt>value</tt>' shall be a pointer value that points to a value that was
-allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.<p>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
+</div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> call <va_list> ()* %llvm.va_start()<br></pre>
+<h5>Overview:</h5>
+<p>The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt><arglist></tt>
+for subsequent use by the variable argument intrinsics.</p>
<h5>Semantics:</h5>
+<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
+macro available in C. In a target-dependent way, it initializes and
+returns a <tt>va_list</tt> element, so that the next <tt>vaarg</tt>
+will produce the first variable argument passed to the function. Unlike
+the C <tt>va_start</tt> macro, this intrinsic does not need to know the
+last argument of the function, the compiler can figure that out.</p>
+<p>Note that this intrinsic function is only legal to be called from
+within the body of a variable argument function.</p>
+</div>
-Access to the memory pointed to by the pointer is not longer defined after this instruction executes.<p>
-
-<h5>Example:</h5>
-<pre>
- %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
- free [4 x ubyte]* %array
-</pre>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
+</div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre> call void (<va_list>)* %llvm.va_end(<va_list> <arglist>)<br></pre>
+<h5>Overview:</h5>
+<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt><arglist></tt>
+which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
+or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
+<h5>Arguments:</h5>
+<p>The argument is a <tt>va_list</tt> to destroy.</p>
+<h5>Semantics:</h5>
+<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
+macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
+Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
+ href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
+with calls to <tt>llvm.va_end</tt>.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_alloca"><h4><hr size=0>'<tt>alloca</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = alloca <type>, uint <NumElements> <i>; yields {type*}:result</i>
- <result> = alloca <type> <i>; yields {type*}:result</i>
+ call <va_list> (<va_list>)* %llvm.va_copy(<va_list> <destarglist>)
</pre>
<h5>Overview:</h5>
-The '<tt>alloca</tt>' instruction allocates memory on the current stack frame of
-the procedure that is live until the current function returns to its caller.<p>
+<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
+from the source argument list to the destination argument list.</p>
<h5>Arguments:</h5>
-The the '<tt>alloca</tt>' instruction allocates
-<tt>sizeof(<type>)*NumElements</tt> bytes of memory on the runtime stack,
-returning a pointer of the appropriate type to the program. The second form of
-the instruction is a shorter version of the first that defaults to allocating
-one element.<p>
-
-'<tt>type</tt>' may be any sized type.<p>
+<p>The argument is the <tt>va_list</tt> to copy.</p>
<h5>Semantics:</h5>
-Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d memory is
-automatically released when the function returns. The '<tt>alloca</tt>'
-instruction is commonly used to represent automatic variables that must have an
-address available. When the function returns (either with the <tt><a
-href="#i_ret">ret</a></tt> or <tt><a href="#i_invoke">invoke</a></tt>
-instructions), the memory is reclaimed.<p>
+<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
+macro available in C. In a target-dependent way, it copies the source
+<tt>va_list</tt> element into the returned list. This intrinsic is necessary
+because the <tt><a href="#i_va_start">llvm.va_start</a></tt> intrinsic may be
+arbitrarily complex and require memory allocation, for example.</p>
-<h5>Example:</h5>
-<pre>
- %ptr = alloca int <i>; yields {int*}:ptr</i>
- %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
-</pre>
+</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
+</div>
+
+<div class="doc_text">
+
+<p>
+LLVM support for <a href="GarbageCollection.html">Accurate Garbage
+Collection</a> requires the implementation and generation of these intrinsics.
+These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
+stack</a>, as well as garbage collector implementations that require <a
+href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
+Front-ends for type-safe garbage collected languages should generate these
+intrinsics to make use of the LLVM garbage collectors. For more details, see <a
+href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_load"><h4><hr size=0>'<tt>load</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = load <ty>* <pointer>
- <result> = volatile load <ty>* <pointer>
+ call void (<ty>**, <ty2>*)* %llvm.gcroot(<ty>** %ptrloc, <ty2>* %metadata)
</pre>
<h5>Overview:</h5>
-The '<tt>load</tt>' instruction is used to read from memory.<p>
+
+<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
+the code generator, and allows some metadata to be associated with it.</p>
<h5>Arguments:</h5>
-The argument to the '<tt>load</tt>' instruction specifies the memory address to
-load from. The pointer must point to a <a href="t_firstclass">first class</a>
-type. If the <tt>load</tt> is marked as <tt>volatile</tt> then the optimizer is
-not allowed to modify the number or order of execution of this <tt>load</tt>
-with other volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
-instructions. <p>
+<p>The first argument specifies the address of a stack object that contains the
+root pointer. The second pointer (which must be either a constant or a global
+value address) contains the meta-data to be associated with the root.</p>
<h5>Semantics:</h5>
-The location of memory pointed to is loaded.
-
-<h5>Examples:</h5>
-<pre>
- %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
- <a href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
- %val = load int* %ptr <i>; yields {int}:val = int 3</i>
-</pre>
-
+<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
+location. At compile-time, the code generator generates information to allow
+the runtime to find the pointer at GC safe points.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_store"><h4><hr size=0>'<tt>store</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i>
- volatile store <ty> <value>, <ty>* <pointer> <i>; yields {void}</i>
+ call sbyte* (sbyte**)* %llvm.gcread(sbyte** %Ptr)
</pre>
<h5>Overview:</h5>
-The '<tt>store</tt>' instruction is used to write to memory.<p>
-<h5>Arguments:</h5>
+<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
+locations, allowing garbage collector implementations that require read
+barriers.</p>
-There are two arguments to the '<tt>store</tt>' instruction: a value to store
-and an address to store it into. The type of the '<tt><pointer></tt>'
-operand must be a pointer to the type of the '<tt><value></tt>' operand.
-If the <tt>store</tt> is marked as <tt>volatile</tt> then the optimizer is not
-allowed to modify the number or order of execution of this <tt>store</tt> with
-other volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
-instructions.<p>
+<h5>Arguments:</h5>
-<h5>Semantics:</h5> The contents of memory are updated to contain
-'<tt><value></tt>' at the location specified by the
-'<tt><pointer></tt>' operand.<p>
+<p>The argument is the address to read from, which should be an address
+allocated from the garbage collector.</p>
-<h5>Example:</h5>
-<pre>
- %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
- <a href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
- %val = load int* %ptr <i>; yields {int}:val = int 3</i>
-</pre>
+<h5>Semantics:</h5>
+<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
+instruction, but may be replaced with substantially more complex code by the
+garbage collector runtime, as needed.</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_getelementptr"><h4><hr size=0>'<tt>getelementptr</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
+
<pre>
- <result> = getelementptr <ty>* <ptrval>{, long <aidx>|, ubyte <sidx>}*
+ call void (sbyte*, sbyte**)* %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
</pre>
<h5>Overview:</h5>
-The '<tt>getelementptr</tt>' instruction is used to get the address of a
-subelement of an aggregate data structure.<p>
+<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
+locations, allowing garbage collector implementations that require write
+barriers (such as generational or reference counting collectors).</p>
<h5>Arguments:</h5>
-This instruction takes a list of <tt>long</tt> values and <tt>ubyte</tt>
-constants that indicate what form of addressing to perform. The actual types of
-the arguments provided depend on the type of the first pointer argument. The
-'<tt>getelementptr</tt>' instruction is used to index down through the type
-levels of a structure.<p>
+<p>The first argument is the reference to store, and the second is the heap
+location to store to.</p>
-For example, lets consider a C code fragment and how it gets compiled to
-LLVM:<p>
+<h5>Semantics:</h5>
-<pre>
-struct RT {
- char A;
- int B[10][20];
- char C;
-};
-struct ST {
- int X;
- double Y;
- struct RT Z;
-};
-
-int *foo(struct ST *s) {
- return &s[1].Z.B[5][13];
-}
-</pre>
+<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
+instruction, but may be replaced with substantially more complex code by the
+garbage collector runtime, as needed.</p>
-The LLVM code generated by the GCC frontend is:
+</div>
-<pre>
-%RT = type { sbyte, [10 x [20 x int]], sbyte }
-%ST = type { int, double, %RT }
-int* "foo"(%ST* %s) {
- %reg = getelementptr %ST* %s, long 1, ubyte 2, ubyte 1, long 5, long 13
- ret int* %reg
-}
-</pre>
-<h5>Semantics:</h5>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_codegen">Code Generator Intrinsics</a>
+</div>
-The index types specified for the '<tt>getelementptr</tt>' instruction depend on
-the pointer type that is being index into. <a href="t_pointer">Pointer</a> and
-<a href="t_array">array</a> types require '<tt>long</tt>' values, and <a
-href="t_struct">structure</a> types require '<tt>ubyte</tt>'
-<b>constants</b>.<p>
-
-In the example above, the first index is indexing into the '<tt>%ST*</tt>' type,
-which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT }</tt>'
-type, a structure. The second index indexes into the third element of the
-structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]], sbyte
-}</tt>' type, another structure. The third index indexes into the second
-element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
-array. The two dimensions of the array are subscripted into, yielding an
-'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer
-to this element, thus yielding a '<tt>int*</tt>' type.<p>
+<div class="doc_text">
+<p>
+These intrinsics are provided by LLVM to expose special features that may only
+be implemented with code generator support.
+</p>
-Note that it is perfectly legal to index partially through a structure,
-returning a pointer to an inner element. Because of this, the LLVM code for the
-given testcase is equivalent to:<p>
+</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
<pre>
-int* "foo"(%ST* %s) {
- %t1 = getelementptr %ST* %s , long 1 <i>; yields %ST*:%t1</i>
- %t2 = getelementptr %ST* %t1, long 0, ubyte 2 <i>; yields %RT*:%t2</i>
- %t3 = getelementptr %RT* %t2, long 0, ubyte 1 <i>; yields [10 x [20 x int]]*:%t3</i>
- %t4 = getelementptr [10 x [20 x int]]* %t3, long 0, long 5 <i>; yields [20 x int]*:%t4</i>
- %t5 = getelementptr [20 x int]* %t4, long 0, long 13 <i>; yields int*:%t5</i>
- ret int* %t5
-}
+ call void* ()* %llvm.returnaddress(uint <level>)
</pre>
+<h5>Overview:</h5>
+<p>
+The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
+indicating the return address of the current function or one of its callers.
+</p>
-<h5>Example:</h5>
-<pre>
- <i>; yields [12 x ubyte]*:aptr</i>
- %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, ubyte 1
-</pre>
+<h5>Arguments:</h5>
+<p>
+The argument to this intrinsic indicates which function to return the address
+for. Zero indicates the calling function, one indicates its caller, etc. The
+argument is <b>required</b> to be a constant integer value.
+</p>
+<h5>Semantics:</h5>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="otherops">Other Operations
-</b></font></td></tr></table><ul>
+<p>
+The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
+the return address of the specified call frame, or zero if it cannot be
+identified. The value returned by this intrinsic is likely to be incorrect or 0
+for arguments other than zero, so it should only be used for debugging purposes.
+</p>
-The instructions in this catagory are the "miscellaneous" instructions, which defy better classification.<p>
+<p>
+Note that calling this intrinsic does not prevent function inlining or other
+aggressive transformations, so the value returned may not that of the obvious
+source-language caller.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_phi"><h4><hr size=0>'<tt>phi</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = phi <ty> [ <val0>, <label0>], ...
+ call void* ()* %llvm.frameaddress(uint <level>)
</pre>
<h5>Overview:</h5>
-The '<tt>phi</tt>' instruction is used to implement the φ node in the SSA
-graph representing the function.<p>
+<p>
+The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
+pointer value for the specified stack frame.
+</p>
<h5>Arguments:</h5>
-The type of the incoming values are specified with the first type field. After
-this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
-one pair for each predecessor basic block of the current block.<p>
-
-There must be no non-phi instructions between the start of a basic block and the
-PHI instructions: i.e. PHI instructions must be first in a basic block.<p>
+<p>
+The argument to this intrinsic indicates which function to return the frame
+pointer for. Zero indicates the calling function, one indicates its caller,
+etc. The argument is <b>required</b> to be a constant integer value.
+</p>
<h5>Semantics:</h5>
-At runtime, the '<tt>phi</tt>' instruction logically takes on the value
-specified by the parameter, depending on which basic block we came from in the
-last <a href="#terminators">terminator</a> instruction.<p>
+<p>
+The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
+the frame address of the specified call frame, or zero if it cannot be
+identified. The value returned by this intrinsic is likely to be incorrect or 0
+for arguments other than zero, so it should only be used for debugging purposes.
+</p>
-<h5>Example:</h5>
+<p>
+Note that calling this intrinsic does not prevent function inlining or other
+aggressive transformations, so the value returned may not that of the obvious
+source-language caller.
+</p>
+</div>
-<pre>
-Loop: ; Infinite loop that counts from 0 on up...
- %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
- %nextindvar = add uint %indvar, 1
- br label %Loop
-</pre>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_os">Operating System Intrinsics</a>
+</div>
+
+<div class="doc_text">
+<p>
+These intrinsics are provided by LLVM to support the implementation of
+operating system level code.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_cast"><h4><hr size=0>'<tt>cast .. to</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_readport">'<tt>llvm.readport</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = cast <ty> <value> to <ty2> <i>; yields ty2</i>
+ call <integer type> (<integer type>)* %llvm.readport (<integer type> <address>)
</pre>
<h5>Overview:</h5>
-The '<tt>cast</tt>' instruction is used as the primitive means to convert
-integers to floating point, change data type sizes, and break type safety (by
-casting pointers).<p>
+<p>
+The '<tt>llvm.readport</tt>' intrinsic reads data from the specified hardware
+I/O port.
+</p>
<h5>Arguments:</h5>
-The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
-class value, and a type to cast it to, which must also be a first class type.<p>
+<p>
+The argument to this intrinsic indicates the hardware I/O address from which
+to read the data. The address is in the hardware I/O address namespace (as
+opposed to being a memory location for memory mapped I/O).
+</p>
<h5>Semantics:</h5>
-This instruction follows the C rules for explicit casts when determining how the
-data being cast must change to fit in its new container.<p>
-
-When casting to bool, any value that would be considered true in the context of
-a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
-all else are '<tt>false</tt>'.<p>
-
-When extending an integral value from a type of one signness to another (for
-example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
-<b>source</b> value is signed, and zero-extended if the source value is
-unsigned. <tt>bool</tt> values are always zero extended into either zero or
-one.<p>
-
-<h5>Example:</h5>
-<pre>
- %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
- %Y = cast int 123 to bool <i>; yields bool:true</i>
-</pre>
-
+<p>
+The '<tt>llvm.readport</tt>' intrinsic reads data from the hardware I/O port
+specified by <i>address</i> and returns the value. The address and return
+value must be integers, but the size is dependent upon the platform upon which
+the program is code generated. For example, on x86, the address must be an
+unsigned 16 bit value, and the return value must be 8, 16, or 32 bits.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_call"><h4><hr size=0>'<tt>call</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <result> = call <ty>* <fnptrval>(<param list>)
+ call void (<integer type>, <integer type>)*
+ %llvm.writeport (<integer type> <value>,
+ <integer type> <address>)
</pre>
<h5>Overview:</h5>
-The '<tt>call</tt>' instruction represents a simple function call.<p>
+<p>
+The '<tt>llvm.writeport</tt>' intrinsic writes data to the specified hardware
+I/O port.
+</p>
<h5>Arguments:</h5>
-This instruction requires several arguments:<p>
-<ol>
-
-<li>'<tt>ty</tt>': shall be the signature of the pointer to function value being
-invoked. The argument types must match the types implied by this signature.<p>
-
-<li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to be
-invoked. In most cases, this is a direct function invocation, but indirect
-<tt>call</tt>s are just as possible, calling an arbitrary pointer to function
-values.<p>
+<p>
+The first argument is the value to write to the I/O port.
+</p>
-<li>'<tt>function args</tt>': argument list whose types match the function
-signature argument types. If the function signature indicates the function
-accepts a variable number of arguments, the extra arguments can be specified.
-</ol>
+<p>
+The second argument indicates the hardware I/O address to which data should be
+written. The address is in the hardware I/O address namespace (as opposed to
+being a memory location for memory mapped I/O).
+</p>
<h5>Semantics:</h5>
-The '<tt>call</tt>' instruction is used to cause control flow to transfer to a
-specified function, with its incoming arguments bound to the specified values.
-Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called function,
-control flow continues with the instruction after the function call, and the
-return value of the function is bound to the result argument. This is a simpler
-case of the <a href="#i_invoke">invoke</a> instruction.<p>
-
-<h5>Example:</h5>
-<pre>
- %retval = call int %test(int %argc)
- call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
+<p>
+The '<tt>llvm.writeport</tt>' intrinsic writes <i>value</i> to the I/O port
+specified by <i>address</i>. The address and value must be integers, but the
+size is dependent upon the platform upon which the program is code generated.
+For example, on x86, the address must be an unsigned 16 bit value, and the
+value written must be 8, 16, or 32 bits in length.
+</p>
-</pre>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_vanext"><h4><hr size=0>'<tt>vanext</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_readio">'<tt>llvm.readio</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <resultarglist> = vanext <va_list> <arglist>, <argty>
+ call <result> (<ty>*)* %llvm.readio (<ty> * <pointer>)
</pre>
<h5>Overview:</h5>
-The '<tt>vanext</tt>' instruction is used to access arguments passed through
-the "variable argument" area of a function call. It is used to implement the
-<tt>va_arg</tt> macro in C.<p>
+<p>
+The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
+address.
+</p>
<h5>Arguments:</h5>
-This instruction takes a <tt>valist</tt> value and the type of the argument. It
-returns another <tt>valist</tt>.
+<p>
+The argument to this intrinsic is a pointer indicating the memory address from
+which to read the data. The data must be a
+<a href="#t_firstclass">first class</a> type.
+</p>
<h5>Semantics:</h5>
-The '<tt>vanext</tt>' instruction advances the specified <tt>valist</tt> past
-an argument of the specified type. In conjunction with the <a
-href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement the
-<tt>va_arg</tt> macro available in C. For more information, see the variable
-argument handling <a href="#int_varargs">Intrinsic Functions</a>.<p>
-
-It is legal for this instruction to be called in a function which does not take
-a variable number of arguments, for example, the <tt>vfprintf</tt> function.<p>
-
-<tt>vanext</tt> is an LLVM instruction instead of an <a
-href="#intrinsics">intrinsic function</a> because it takes an type as an
-argument.</p>
-
-<h5>Example:</h5>
-
-See the <a href="#int_varargs">variable argument processing</a> section.<p>
+<p>
+The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
+location specified by <i>pointer</i> and returns the value. The argument must
+be a pointer, and the return value must be a
+<a href="#t_firstclass">first class</a> type. However, certain architectures
+may not support I/O on all first class types. For example, 32 bit processors
+may only support I/O on data types that are 32 bits or less.
+</p>
+<p>
+This intrinsic enforces an in-order memory model for llvm.readio and
+llvm.writeio calls on machines that use dynamic scheduling. Dynamically
+scheduled processors may execute loads and stores out of order, re-ordering at
+run time accesses to memory mapped I/O registers. Using these intrinsics
+ensures that accesses to memory mapped I/O registers occur in program order.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_vaarg"><h4><hr size=0>'<tt>vaarg</tt>' Instruction</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- <resultval> = vaarg <va_list> <arglist>, <argty>
+ call void (<ty1>, <ty2>*)* %llvm.writeio (<ty1> <value>, <ty2> * <pointer>)
</pre>
<h5>Overview:</h5>
-The '<tt>vaarg</tt>' instruction is used to access arguments passed through
-the "variable argument" area of a function call. It is used to implement the
-<tt>va_arg</tt> macro in C.<p>
+<p>
+The '<tt>llvm.writeio</tt>' intrinsic writes data to the specified memory
+mapped I/O address.
+</p>
<h5>Arguments:</h5>
-This instruction takes a <tt>valist</tt> value and the type of the argument. It
-returns a value of the specified argument type.
+<p>
+The first argument is the value to write to the memory mapped I/O location.
+The second argument is a pointer indicating the memory address to which the
+data should be written.
+</p>
<h5>Semantics:</h5>
-The '<tt>vaarg</tt>' instruction loads an argument of the specified type from
-the specified <tt>va_list</tt>. In conjunction with the <a
-href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to implement the
-<tt>va_arg</tt> macro available in C. For more information, see the variable
-argument handling <a href="#int_varargs">Intrinsic Functions</a>.<p>
-
-It is legal for this instruction to be called in a function which does not take
-a variable number of arguments, for example, the <tt>vfprintf</tt> function.<p>
-
-<tt>vaarg</tt> is an LLVM instruction instead of an <a
-href="#intrinsics">intrinsic function</a> because it takes an type as an
-argument.</p>
-
-<h5>Example:</h5>
-
-See the <a href="#int_varargs">variable argument processing</a> section.<p>
-
+<p>
+The '<tt>llvm.writeio</tt>' intrinsic writes <i>value</i> to the memory mapped
+I/O address specified by <i>pointer</i>. The value must be a
+<a href="#t_firstclass">first class</a> type. However, certain architectures
+may not support I/O on all first class types. For example, 32 bit processors
+may only support I/O on data types that are 32 bits or less.
+</p>
+<p>
+This intrinsic enforces an in-order memory model for llvm.readio and
+llvm.writeio calls on machines that use dynamic scheduling. Dynamically
+scheduled processors may execute loads and stores out of order, re-ordering at
+run time accesses to memory mapped I/O registers. Using these intrinsics
+ensures that accesses to memory mapped I/O registers occur in program order.
+</p>
+</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_libc">Standard C Library Intrinsics</a>
+</div>
-<!-- *********************************************************************** -->
-</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
-<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
-<a name="intrinsics">Intrinsic Functions
-</b></font></td></tr></table><ul>
-<!-- *********************************************************************** -->
+<div class="doc_text">
+<p>
+LLVM provides intrinsics for a few important standard C library functions.
+These intrinsics allow source-language front-ends to pass information about the
+alignment of the pointer arguments to the code generator, providing opportunity
+for more efficient code generation.
+</p>
-LLVM supports the notion of an "intrinsic function". These functions have well
-known names and semantics, and are required to follow certain restrictions.
-Overall, these instructions represent an extension mechanism for the LLVM
-language that does not require changing all of the transformations in LLVM to
-add to the language (or the bytecode reader/writer, the parser, etc...).<p>
+</div>
-Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix, this
-prefix is reserved in LLVM for intrinsic names, thus functions may not be named
-this. Intrinsic functions must always be external functions: you cannot define
-the body of intrinsic functions. Intrinsic functions may only be used in call
-or invoke instructions: it is illegal to take the address of an intrinsic
-function. Additionally, because intrinsic functions are part of the LLVM
-language, it is required that they all be documented here if any are added.<p>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
+</div>
-Unless an intrinsic function is target-specific, there must be a lowering pass
-to eliminate the intrinsic or all backends must support the intrinsic
-function.<p>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre>
+ call void (sbyte*, sbyte*, uint, uint)* %llvm.memcpy(sbyte* <dest>, sbyte* <src>,
+ uint <len>, uint <align>)
+</pre>
-<!-- ======================================================================= -->
-</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
-<tr><td> </td><td width="100%"> <font color="#EEEEFF" face="Georgia,Palatino"><b>
-<a name="int_varargs">Variable Argument Handling Intrinsics
-</b></font></td></tr></table><ul>
+<h5>Overview:</h5>
-Variable argument support is defined in LLVM with the <a
-href="#i_vanext"><tt>vanext</tt></a> instruction and these three intrinsic
-functions. These functions are related to the similarly named macros defined in
-the <tt><stdarg.h></tt> header file.<p>
+<p>
+The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
+location to the destination location.
+</p>
-All of these functions operate on arguments that use a target-specific value
-type "<tt>va_list</tt>". The LLVM assembly language reference manual does not
-define what this type is, so all transformations should be prepared to handle
-intrinsics with any type used.<p>
+<p>
+Note that, unlike the standard libc function, the <tt>llvm.memcpy</tt> intrinsic
+does not return a value, and takes an extra alignment argument.
+</p>
-This example shows how the <a href="#i_vanext"><tt>vanext</tt></a> instruction
-and the variable argument handling intrinsic functions are used.<p>
+<h5>Arguments:</h5>
-<pre>
-int %test(int %X, ...) {
- ; Initialize variable argument processing
- %ap = call sbyte*()* %<a href="#i_va_start">llvm.va_start</a>()
+<p>
+The first argument is a pointer to the destination, the second is a pointer to
+the source. The third argument is an (arbitrarily sized) integer argument
+specifying the number of bytes to copy, and the fourth argument is the alignment
+of the source and destination locations.
+</p>
- ; Read a single integer argument
- %tmp = vaarg sbyte* %ap, int
+<p>
+If the call to this intrinisic has an alignment value that is not 0 or 1, then
+the caller guarantees that the size of the copy is a multiple of the alignment
+and that both the source and destination pointers are aligned to that boundary.
+</p>
- ; Advance to the next argument
- %ap2 = vanext sbyte* %ap, int
+<h5>Semantics:</h5>
- ; Demonstrate usage of llvm.va_copy and llvm.va_end
- %aq = call sbyte* (sbyte*)* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2)
- call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq)
+<p>
+The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
+location to the destination location, which are not allowed to overlap. It
+copies "len" bytes of memory over. If the argument is known to be aligned to
+some boundary, this can be specified as the fourth argument, otherwise it should
+be set to 0 or 1.
+</p>
+</div>
- ; Stop processing of arguments.
- call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2)
- ret int %tmp
-}
-</pre>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_va_start"><h4><hr size=0>'<tt>llvm.va_start</tt>' Intrinsic</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- call va_list ()* %llvm.va_start()
+ call void (sbyte*, sbyte*, uint, uint)* %llvm.memmove(sbyte* <dest>, sbyte* <src>,
+ uint <len>, uint <align>)
</pre>
<h5>Overview:</h5>
-The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt><arglist></tt>
-for subsequent use by the variable argument intrinsics.<p>
+<p>
+The '<tt>llvm.memmove</tt>' intrinsic moves a block of memory from the source
+location to the destination location. It is similar to the '<tt>llvm.memcpy</tt>'
+intrinsic but allows the two memory locations to overlap.
+</p>
-<h5>Semantics:</h5>
+<p>
+Note that, unlike the standard libc function, the <tt>llvm.memmove</tt> intrinsic
+does not return a value, and takes an extra alignment argument.
+</p>
+
+<h5>Arguments:</h5>
+
+<p>
+The first argument is a pointer to the destination, the second is a pointer to
+the source. The third argument is an (arbitrarily sized) integer argument
+specifying the number of bytes to copy, and the fourth argument is the alignment
+of the source and destination locations.
+</p>
+
+<p>
+If the call to this intrinisic has an alignment value that is not 0 or 1, then
+the caller guarantees that the size of the copy is a multiple of the alignment
+and that both the source and destination pointers are aligned to that boundary.
+</p>
-The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
-macro available in C. In a target-dependent way, it initializes and returns a
-<tt>va_list</tt> element, so that the next <tt>vaarg</tt> will produce the first
-variable argument passed to the function. Unlike the C <tt>va_start</tt> macro,
-this intrinsic does not need to know the last argument of the function, the
-compiler can figure that out.<p>
+<h5>Semantics:</h5>
-Note that this intrinsic function is only legal to be called from within the
-body of a variable argument function.<p>
+<p>
+The '<tt>llvm.memmove</tt>' intrinsic copies a block of memory from the source
+location to the destination location, which may overlap. It
+copies "len" bytes of memory over. If the argument is known to be aligned to
+some boundary, this can be specified as the fourth argument, otherwise it should
+be set to 0 or 1.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_va_end"><h4><hr size=0>'<tt>llvm.va_end</tt>' Intrinsic</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- call void (va_list)* %llvm.va_end(va_list <arglist>)
+ call void (sbyte*, ubyte, uint, uint)* %llvm.memset(sbyte* <dest>, ubyte <val>,
+ uint <len>, uint <align>)
</pre>
<h5>Overview:</h5>
-The '<tt>llvm.va_end</tt>' intrinsic destroys <tt><arglist></tt> which has
-been initialized previously with <tt><a
-href="#i_va_start">llvm.va_start</a></tt> or <tt><a
-href="#i_va_copy">llvm.va_copy</a></tt>.<p>
+<p>
+The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
+byte value.
+</p>
+
+<p>
+Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
+does not return a value, and takes an extra alignment argument.
+</p>
<h5>Arguments:</h5>
-The argument is a <tt>va_list</tt> to destroy.<p>
+<p>
+The first argument is a pointer to the destination to fill, the second is the
+byte value to fill it with, the third argument is an (arbitrarily sized) integer
+argument specifying the number of bytes to fill, and the fourth argument is the
+known alignment of destination location.
+</p>
-<h5>Semantics:</h5>
+<p>
+If the call to this intrinisic has an alignment value that is not 0 or 1, then
+the caller guarantees that the size of the copy is a multiple of the alignment
+and that the destination pointer is aligned to that boundary.
+</p>
-The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt> macro
-available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
-Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
-href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly with calls
-to <tt>llvm.va_end</tt>.<p>
+<h5>Semantics:</h5>
+<p>
+The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
+destination location. If the argument is known to be aligned to some boundary,
+this can be specified as the fourth argument, otherwise it should be set to 0 or
+1.
+</p>
+</div>
<!-- _______________________________________________________________________ -->
-</ul><a name="i_va_copy"><h4><hr size=0>'<tt>llvm.va_copy</tt>' Intrinsic</h4><ul>
+<div class="doc_subsubsection">
+ <a name="i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
<h5>Syntax:</h5>
<pre>
- call va_list (va_list)* %llvm.va_copy(va_list <destarglist>)
+ call bool (<float or double>, <float or double>)* %llvm.isunordered(<float or double> Val1,
+ <float or double> Val2)
</pre>
<h5>Overview:</h5>
-The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
-the source argument list to the destination argument list.<p>
+<p>
+The '<tt>llvm.isunordered</tt>' intrinsic returns true if either or both of the
+specified floating point values is a NAN.
+</p>
<h5>Arguments:</h5>
-The argument is the <tt>va_list</tt> to copy.
+<p>
+The arguments are floating point numbers of the same type.
+</p>
<h5>Semantics:</h5>
-The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
-available in C. In a target-dependent way, it copies the source
-<tt>va_list</tt> element into the returned list. This intrinsic is necessary
-because the <tt><a href="i_va_start">llvm.va_start</a></tt> intrinsic may be
-arbitrarily complex and require memory allocation, for example.<p>
+<p>
+If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
+false.
+</p>
+</div>
-<!-- *********************************************************************** -->
-</ul>
-<!-- *********************************************************************** -->
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_debugger">Debugger Intrinsics</a>
+</div>
+
+<div class="doc_text">
+<p>
+The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
+are described in the <a
+href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
+Debugging</a> document.
+</p>
+</div>
+
+
+<!-- *********************************************************************** -->
<hr>
-<font size=-1>
-<address><a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
-<!-- Created: Tue Jan 23 15:19:28 CST 2001 -->
-<!-- hhmts start -->
-Last modified: Tue Oct 21 10:43:36 CDT 2003
-<!-- hhmts end -->
-</font>
-</body></html>
+<address>
+ <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
+ src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
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+ src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
+
+ <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
+ <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
+ Last modified: $Date$
+</address>
+</body>
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