<li><a href="#callingconv">Calling Conventions</a></li>
<li><a href="#globalvars">Global Variables</a></li>
<li><a href="#functionstructure">Functions</a></li>
+ <li><a href="#aliasstructure">Aliases</a>
<li><a href="#paramattrs">Parameter Attributes</a></li>
<li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
<li><a href="#datalayout">Data Layout</a></li>
</li>
<li><a href="#int_debugger">Debugger intrinsics</a></li>
<li><a href="#int_eh">Exception Handling intrinsics</a></li>
+ <li><a href="#int_trampoline">Trampoline Intrinsic</a>
+ <ol>
+ <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
+ <li><a href="#int_general">General intrinsics</a>
+ <ol>
+ <li><a href="#int_var_annotation">
+ <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
+ </ol>
+ <ol>
+ <li><a href="#int_annotation">
+ <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
+ </ol>
+ </li>
</ol>
</li>
</ol>
<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
+different forms: as an in-memory compiler IR, as an on-disk bitcode
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
accepts and what is considered 'well formed'. For example, the
following instruction is syntactically okay, but not well formed:</p>
+<div class="doc_code">
<pre>
-
%x = <a href="#i_add">add</a> i32 1, %x
+%x = <a href="#i_add">add</a> i32 1, %x
</pre>
+</div>
<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
+the optimizer before it outputs bitcode. The violations pointed out
by the verifier pass indicate bugs in transformation passes or input to
the parser.</p>
+</div>
-<!-- Describe the typesetting conventions here. --> </div>
+<!-- Describe the typesetting conventions here. -->
<!-- *********************************************************************** -->
<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
<div class="doc_text">
-<p>LLVM uses three different forms of identifiers, for different
-purposes:</p>
+ <p>LLVM identifiers come in two basic types: global and local. Global
+ identifiers (functions, global variables) begin with the @ character. Local
+ identifiers (register names, types) begin with the % character. Additionally,
+ there are three different formats for identifiers, for different purposes:
<ol>
- <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>'.
+ <li>Named values are represented as a string of characters with their 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>
+ with quotes. In this way, anything except a <tt>"</tt> character can
+ be used in a named value.</li>
- <li>Unnamed values are represented as an unsigned numeric value with a '%'
- prefix. For example, %12, %2, %44.</li>
+ <li>Unnamed values are represented as an unsigned numeric value with their
+ 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
+<p>LLVM requires that values start with a prefix 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
'<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_primitive">i32</a></tt>', etc...),
and others. These reserved words cannot conflict with variable names, because
-none of them start with a '%' character.</p>
+none of them start with a prefix character ('%' or '@').</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>
+<div class="doc_code">
<pre>
-
%result = <a href="#i_mul">mul</a> i32 %X, 8
+%result = <a href="#i_mul">mul</a> i32 %X, 8
</pre>
+</div>
<p>After strength reduction:</p>
+<div class="doc_code">
<pre>
-
%result = <a href="#i_shl">shl</a> i32 %X, i8 3
+%result = <a href="#i_shl">shl</a> i32 %X, i8 3
</pre>
+</div>
<p>And the hard way:</p>
+<div class="doc_code">
<pre>
-
<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
-
<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
-
%result = <a href="#i_add">add</a> i32 %1, %1
+<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
+<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
+%result = <a href="#i_add">add</a> i32 %1, %1
</pre>
+</div>
<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
important lexical features of LLVM:</p>
global variable) definitions, resolves forward declarations, and merges
symbol table entries. Here is an example of the "hello world" module:</p>
+<div class="doc_code">
<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 i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i>
+<a href="#identifiers">
@.LC0</a> = <a href="#linkage_internal">internal</a> <a
+ href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
<i>; External declaration of the puts function</i>
-<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
+<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
<i>; Definition of main function</i>
-define i32 %main() { <i>; i32()* </i>
+define i32 @main() { <i>; i32()* </i>
<i>; Convert [13x i8 ]* to i8 *...</i>
%cast210 = <a
- href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
+ href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
<i>; Call puts function to write out the string to stdout...</i>
<a
- href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
+ href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
<a
- href="#i_ret">ret</a> i32 0<br>}<br></pre>
+ href="#i_ret">ret</a> i32 0<br>}<br>
+</pre>
+</div>
<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>"
directly.
</dd>
+ <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
+
+ <dd>On ELF, protected visibility indicates that the symbol will be placed in
+ the dynamic symbol table, but that references within the defining module will
+ bind to the local symbol. That is, the symbol cannot be overridden by another
+ module.
+ </dd>
</dl>
</div>
<p>For example, the following defines a global with an initializer, section,
and alignment:</p>
+<div class="doc_code">
<pre>
- %G = constant float 1.0, section "foo", align 4
+@G = constant float 1.0, section "foo", align 4
</pre>
+</div>
</div>
with a <a href="#terminators">terminator</a> instruction (such as a branch or
function return).</p>
-<p>The first basic block in a program is special in two ways: it is immediately
+<p>The first basic block in a function 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>
-<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 resolve references to each
-appropriately.</p>
-
<p>LLVM allows an explicit section to be specified for functions. If the target
supports it, it will emit functions to the section specified.</p>
</div>
<div class="doc_text">
<p>Aliases act as "second name" for the aliasee value (which can be either
- function or global variable). Aliases may have an
+ function or global variable or bitcast of global value). Aliases may have an
optional <a href="#linkage">linkage type</a>, and an
optional <a href="#visibility">visibility style</a>.</p>
<h5>Syntax:</h5>
- <pre>
- @<Name> = [Linkage] [Visibility] alias <AliaseeTy> @<Aliasee>
- </pre>
+<div class="doc_code">
+<pre>
+@<Name> = [Linkage] [Visibility] alias <AliaseeTy> @<Aliasee>
+</pre>
+</div>
</div>
<p>Parameter attributes are simple keywords that follow the type specified. If
multiple parameter attributes are needed, they are space separated. For
- example:</p><pre>
- %someFunc = i16 (i8 sext %someParam) zext
- %someFunc = i16 (i8 zext %someParam) zext</pre>
+ example:</p>
+
+<div class="doc_code">
+<pre>
+%someFunc = i16 (i8 signext %someParam) zeroext
+%someFunc = i16 (i8 zeroext %someParam) zeroext
+</pre>
+</div>
+
<p>Note that the two function types above are unique because the parameter has
- a different attribute (sext in the first one, zext in the second). Also note
- that the attribute for the function result (zext) comes immediately after the
- argument list.</p>
+ a different attribute (<tt>signext</tt> in the first one, <tt>zeroext</tt> in
+ the second). Also note that the attribute for the function result
+ (<tt>zeroext</tt>) comes immediately after the argument list.</p>
<p>Currently, only the following parameter attributes are defined:</p>
<dl>
- <dt><tt>zext</tt></dt>
+ <dt><tt>zeroext</tt></dt>
<dd>This indicates that the parameter should be zero extended just before
a call to this function.</dd>
- <dt><tt>sext</tt></dt>
+ <dt><tt>signext</tt></dt>
<dd>This indicates that the parameter should be sign extended just before
a call to this function.</dd>
<dt><tt>inreg</tt></dt>
<dt><tt>sret</tt></dt>
<dd>This indicates that the parameter specifies the address of a structure
that is the return value of the function in the source program.</dd>
+ <dt><tt>noalias</tt></dt>
+ <dd>This indicates that the parameter not alias any other object or any
+ other "noalias" objects during the function call.
<dt><tt>noreturn</tt></dt>
<dd>This function attribute indicates that the function never returns. This
indicates to LLVM that every call to this function should be treated as if
<dd>This function attribute indicates that the function type does not use
the unwind instruction and does not allow stack unwinding to propagate
through it.</dd>
+ <dt><tt>nest</tt></dt>
+ <dd>This indicates that the parameter can be excised using the
+ <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
</dl>
</div>
desired. The syntax is very simple:
</p>
-<div class="doc_code"><pre>
- module asm "inline asm code goes here"
- module asm "more can go here"
-</pre></div>
+<div class="doc_code">
+<pre>
+module asm "inline asm code goes here"
+module asm "more can go here"
+</pre>
+</div>
<p>The strings can contain any character by escaping non-printable characters.
The escape sequence used is simply "\xx" where "xx" is the two digit hex code
<tbody>
<tr><th>Type</th><th>Description</th></tr>
<tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
- <tr><td><tt>i8</tt></td><td>8-bit value</td></tr>
- <tr><td><tt>i32</tt></td><td>32-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>
<table>
<tbody>
<tr><th>Type</th><th>Description</th></tr>
- <tr><td><tt>i1</tt></td><td>True or False value</td></tr>
- <tr><td><tt>i16</tt></td><td>16-bit value</td></tr>
- <tr><td><tt>i64</tt></td><td>64-bit value</td></tr>
+ <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
<tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
</tbody>
</table>
<tr><th>Classification</th><th>Types</th></tr>
<tr>
<td><a name="t_integer">integer</a></td>
- <td><tt>i1, i8, i16, i32, i64</tt></td>
+ <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
</tr>
<tr>
<td><a name="t_floating">floating point</a></td>
</tr>
<tr>
<td><a name="t_firstclass">first class</a></td>
- <td><tt>i1, i8, i16, i32, i64, float, double, <br/>
+ <td><tt>i1, ..., float, double, <br/>
<a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
</td>
</tr>
</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
+
+<div class="doc_text">
+
+<h5>Overview:</h5>
+<p>The integer type is a very simple derived type that simply specifies an
+arbitrary bit width for the integer type desired. Any bit width from 1 bit to
+2^23-1 (about 8 million) can be specified.</p>
+
+<h5>Syntax:</h5>
+
+<pre>
+ iN
+</pre>
+
+<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
+value.</p>
+
+<h5>Examples:</h5>
+<table class="layout">
+ <tr class="layout">
+ <td class="left">
+ <tt>i1</tt><br/>
+ <tt>i4</tt><br/>
+ <tt>i8</tt><br/>
+ <tt>i16</tt><br/>
+ <tt>i32</tt><br/>
+ <tt>i42</tt><br/>
+ <tt>i64</tt><br/>
+ <tt>i1942652</tt><br/>
+ </td>
+ <td class="left">
+ A boolean integer of 1 bit<br/>
+ A nibble sized integer of 4 bits.<br/>
+ A byte sized integer of 8 bits.<br/>
+ A half word sized integer of 16 bits.<br/>
+ A word sized integer of 32 bits.<br/>
+ An integer whose bit width is the answer. <br/>
+ A double word sized integer of 64 bits.<br/>
+ A really big integer of over 1 million bits.<br/>
+ </td>
+ </tr>
+</table>
+</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
<td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
</td>
</tr><tr class="layout">
- <td class="left"><tt>float (i16 sext, i32 *) *
+ <td class="left"><tt>float (i16 signext, i32 *) *
</tt></td>
<td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
an <tt>i16</tt> that should be sign extended and a
<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>{ i32 4, float 17.0, i32* %G }</tt>",
- where "<tt>%G</tt>" is declared as "<tt>%G = external global i32</tt>". Structure constants
+ where "<tt>%G</tt>" is declared as "<tt>@G = external global i32</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>
href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
file:</p>
+<div class="doc_code">
<pre>
- %X = global i32 17
- %Y = global i32 42
- %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
+@X = global i32 17
+@Y = global i32 42
+@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
</pre>
+</div>
</div>
<dd>Floating point extend a constant to another type. The size of CST must be
smaller or equal to the size of TYPE. Both types must be floating point.</dd>
- <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
+ <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
<dd>Convert a floating point constant to the corresponding unsigned integer
constant. TYPE must be an integer type. CST must be floating point. If the
value won't fit in the integer type, the results are undefined.</dd>
inline assembler expression is:
</p>
+<div class="doc_code">
<pre>
- i32 (i32) asm "bswap $0", "=r,r"
+i32 (i32) asm "bswap $0", "=r,r"
</pre>
+</div>
<p>
Inline assembler expressions may <b>only</b> be used as the callee operand of
a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
</p>
+<div class="doc_code">
<pre>
-
%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
+%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
</pre>
+</div>
<p>
Inline asms with side effects not visible in the constraint list must be marked
'<tt>sideeffect</tt>' keyword, like so:
</p>
+<div class="doc_code">
<pre>
- call void asm sideeffect "eieio", ""()
+call void asm sideeffect "eieio", ""()
</pre>
+</div>
<p>TODO: The format of the asm and constraints string still need to be
documented here. Constraints on what can be done (e.g. duplication, moving, etc
<p>The value produced is the integer or floating point difference of
the two operands.</p>
<h5>Example:</h5>
-<pre> <result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
+<pre>
+ <result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
<result> = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
</pre>
</div>
<h5>Syntax:</h5>
<pre> <result> = shl <ty> <var1>, <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>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
href="#t_integer">integer</a> type.</p>
+
<h5>Semantics:</h5>
-<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
+
+<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
+<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
+of bits in <tt>var1</tt>, the result is undefined.</p>
+
<h5>Example:</h5><pre>
<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
<result> = shl i32 4, 2 <i>; yields {i32}: 16</i>
<result> = shl i32 1, 10 <i>; yields {i32}: 1024</i>
+ <result> = shl i32 1, 32 <i>; undefined</i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
<a href="#t_integer">integer</a> type.</p>
<h5>Semantics:</h5>
+
<p>This instruction always performs a logical shift right operation. The most
significant bits of the result will be filled with zero bits after the
-shift.</p>
+shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
+the number of bits in <tt>var1</tt>, the result is undefined.</p>
<h5>Example:</h5>
<pre>
<result> = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
<result> = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
<result> = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
+ <result> = lshr i32 1, 32 <i>; undefined</i>
</pre>
</div>
<h5>Semantics:</h5>
<p>This instruction always performs an arithmetic shift right operation,
The most significant bits of the result will be filled with the sign bit
-of <tt>var1</tt>.</p>
+of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
+larger than the number of bits in <tt>var1</tt>, the result is undefined.
+</p>
<h5>Example:</h5>
<pre>
<result> = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
<result> = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
<result> = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
+ <result> = ashr i32 1, 32 <i>; undefined</i>
</pre>
</div>
<pre>
%array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
- %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
- %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
- %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
- %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
- %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
+ %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
+ %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
+ %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
+ %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
+ %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
</pre>
</div>
<pre>
%ptr = alloca i32 <i>; yields {i32*}:ptr</i>
- %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
- %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
+ %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
+ %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
%ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
</pre>
</div>
<p>For example, let's consider a C code fragment and how it gets
compiled to LLVM:</p>
+<div class="doc_code">
<pre>
- struct RT {
- char A;
- i32 B[10][20];
- char C;
- };
- struct ST {
- i32 X;
- double Y;
- struct RT Z;
- };
-
- define i32 *foo(struct ST *s) {
- return &s[1].Z.B[5][13];
- }
+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>
+</div>
<p>The LLVM code generated by the GCC frontend is:</p>
+<div class="doc_code">
<pre>
- %RT = type { i8 , [10 x [20 x i32]], i8 }
- %ST = type { i32, double, %RT }
+%RT = type { i8 , [10 x [20 x i32]], i8 }
+%ST = type { i32, double, %RT }
- define i32* %foo(%ST* %s) {
- entry:
- %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
- ret i32* %reg
- }
+define i32* %foo(%ST* %s) {
+entry:
+ %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
+ ret i32* %reg
+}
</pre>
+</div>
<h5>Semantics:</h5>
<h5>Semantics:</h5>
<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
-bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
-the operand and the type are the same size, no bit filling is done and the
-cast is considered a <i>no-op cast</i> because no bits change (only the type
-changes).</p>
+bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
<p>When zero extending from i1, the result will always be either 0 or 1.</p>
<p>
The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
-the type <tt>ty2</tt>. When the the operand and the type are the same size,
-no bit filling is done and the cast is considered a <i>no-op cast</i> because
-no bits change (only the type changes).</p>
+the type <tt>ty2</tt>.</p>
<p>When sign extending from i1, the extension always results in -1 or 0.</p>
<h5>Syntax:</h5>
<pre>
- <result> = fp2uint <ty> <value> to <ty2> <i>; yields ty2</i>
+ <result> = fptoui <ty> <value> to <ty2> <i>; yields ty2</i>
</pre>
<h5>Overview:</h5>
-<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
+<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
unsigned integer equivalent of type <tt>ty2</tt>.
</p>
<h5>Arguments:</h5>
-<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
+<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
<a href="#t_floating">floating point</a> value, and a type to cast it to, which
must be an <a href="#t_integer">integer</a> type.</p>
<h5>Semantics:</h5>
-<p> The '<tt>fp2uint</tt>' instruction converts its
+<p> The '<tt>fptoui</tt>' instruction converts its
<a href="#t_floating">floating point</a> operand into the nearest (rounding
towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
the results are undefined.</p>
-<p>When converting to i1, the conversion is done as a comparison against
-zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
-If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
-
<h5>Example:</h5>
<pre>
- %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
- %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
- %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
+ %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
+ %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
+ %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
</pre>
</div>
towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
the results are undefined.</p>
-<p>When converting to i1, the conversion is done as a comparison against
-zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
-If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
-
<h5>Example:</h5>
<pre>
%X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
- %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
+ %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
%X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
</pre>
</div>
<h5>Example:</h5>
<pre>
%X = uitofp i32 257 to float <i>; yields float:257.0</i>
- %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
+ %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
</pre>
</div>
<h5>Example:</h5>
<pre>
%X = sitofp i32 257 to float <i>; yields float:257.0</i>
- %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
+ %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
</pre>
</div>
truncating or zero extending that value to the size of the integer type. If
<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
-are the same size, then nothing is done (<i>no-op cast</i>).</p>
+are the same size, then nothing is done (<i>no-op cast</i>) other than a type
+change.</p>
<h5>Example:</h5>
<pre>
- %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
- %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
+ %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
+ %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
</pre>
</div>
<h5>Example:</h5>
<pre>
- %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
- %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
- %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
+ %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
+ %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
+ %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
</pre>
</div>
<h5>Example:</h5>
<pre>
- %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
+ %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
%Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
%Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
</pre>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-<pre> <result> = icmp <cond> <ty> <var1>, <var2>
-<i>; yields {i1}:result</i>
+<pre> <result> = icmp <cond> <ty> <var1>, <var2> <i>; yields {i1}:result</i>
</pre>
<h5>Overview:</h5>
<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
of its two integer operands.</p>
<h5>Arguments:</h5>
<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
-the condition code which indicates the kind of comparison to perform. It is not
-a value, just a keyword. The possibilities for the condition code are:
+the condition code indicating the kind of comparison to perform. It is not
+a value, just a keyword. The possible condition code are:
<ol>
<li><tt>eq</tt>: equal</li>
<li><tt>ne</tt>: not equal </li>
<tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
</ol>
<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
-values are treated as integers and then compared.</p>
+values are compared as if they were integers.</p>
<h5>Example:</h5>
<pre> <result> = icmp eq i32 4, 5 <i>; yields: result=false</i>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
-<pre> <result> = fcmp <cond> <ty> <var1>, <var2>
-<i>; yields {i1}:result</i>
+<pre> <result> = fcmp <cond> <ty> <var1>, <var2> <i>; yields {i1}:result</i>
</pre>
<h5>Overview:</h5>
<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
of its floating point operands.</p>
<h5>Arguments:</h5>
<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
-the condition code which indicates the kind of comparison to perform. It is not
-a value, just a keyword. The possibilities for the condition code are:
+the condition code indicating the kind of comparison to perform. It is not
+a value, just a keyword. The possible condition code are:
<ol>
<li><tt>false</tt>: no comparison, always returns false</li>
<li><tt>oeq</tt>: ordered and equal</li>
<li><tt>uno</tt>: unordered (either nans)</li>
<li><tt>true</tt>: no comparison, always returns true</li>
</ol>
-<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
+<p><i>Ordered</i> means that neither operand is a QNAN while
<i>unordered</i> means that either operand may be a QNAN.</p>
<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
<a href="#t_floating">floating point</a> typed. They must have identical
types.</p>
-<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
-<i>unordered</i> means that either operand is a QNAN.</p>
<h5>Semantics:</h5>
<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
the condition code given as <tt>cond</tt>. The comparison performed always
<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
+<p>The type of the incoming values is 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>
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>
+<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
+specified by the pair corresponding to the predecessor basic block that executed
+just prior to the current block.</p>
<h5>Example:</h5>
<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
</div>
<h5>Syntax:</h5>
<pre>
- <result> = [tail] call [<a href="#callingconv">cconv</a>] <ty>* <fnptrval>(<param list>)
+ <result> = [tail] call [<a href="#callingconv">cconv</a>] <ty> [<fnty>*] <fnptrval>(<param list>)
</pre>
<h5>Overview:</h5>
to using C calling conventions.
</li>
<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. This type can be omitted if the function is not varargs and
- if the function type does not return a pointer to a function.</p>
+ <p>'<tt>ty</tt>': the type of the call instruction itself which is also
+ the type of the return value. Functions that return no value are marked
+ <tt><a href="#t_void">void</a></tt>.</p>
+ </li>
+ <li>
+ <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
+ value being invoked. The argument types must match the types implied by
+ this signature. This type can be omitted if the function is not varargs
+ and if the function type does not return a pointer to a function.</p>
</li>
<li>
<p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
<h5>Example:</h5>
<pre>
- %retval = call i32 %test(i32 %argc)
- call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
- %X = tail call i32 %foo()
- %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
+ %retval = call i32 @test(i32 %argc)
+ call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
+ %X = tail call i32 @foo()
+ %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
+ %Z = call void %foo(i8 97 signext)
</pre>
</div>
<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 and
-increments the <tt>va_list</tt> to point to the next argument. Again, the
+increments the <tt>va_list</tt> to point to the next argument. The
actual type of <tt>va_list</tt> is target specific.</p>
<h5>Semantics:</h5>
<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 intrinsics 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>
+language that does not require changing all of the transformations in LLVM when
+adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
<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>
-
-<p>Some intrinsic functions can be overloaded. That is, the intrinsic represents
-a family of functions that perform the same operation but on different data
-types. This is most frequent with the integer types. Since LLVM can represent
-over 8 million different integer types, there is a way to declare an intrinsic
-that can be overloaded based on its arguments. Such intrinsics will have the
-names of the arbitrary types encoded into the intrinsic function name, each
-preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an
-integer of any width. This leads to a family of functions such as
-<tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>.
-</p>
-
+prefix is reserved in LLVM for intrinsic names; thus, function names may not
+begin with this prefix. 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 if any are added that they be documented
+here.</p>
+
+<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
+a family of functions that perform the same operation but on different data
+types. Because LLVM can represent over 8 million different integer types,
+overloading is used commonly to allow an intrinsic function to operate on any
+integer type. One or more of the argument types or the result type can be
+overloaded to accept any integer type. Argument types may also be defined as
+exactly matching a previous argument's type or the result type. This allows an
+intrinsic function which accepts multiple arguments, but needs all of them to
+be of the same type, to only be overloaded with respect to a single argument or
+the result.</p>
+
+<p>Overloaded intrinsics will have the names of its overloaded argument types
+encoded into its function name, each preceded by a period. Only those types
+which are overloaded result in a name suffix. Arguments whose type is matched
+against another type do not. For example, the <tt>llvm.ctpop</tt> function can
+take an integer of any width and returns an integer of exactly the same integer
+width. This leads to a family of functions such as
+<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
+Only one type, the return type, is overloaded, and only one type suffix is
+required. Because the argument's type is matched against the return type, it
+does not require its own name suffix.</p>
<p>To learn how to add an intrinsic function, please see the
<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
<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>
+transformations should be prepared to handle these functions regardless of
+the type used.</p>
<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
instruction and the variable argument handling intrinsic functions are
used.</p>
+<div class="doc_code">
<pre>
define i32 @test(i32 %X, ...) {
; Initialize variable argument processing
- %ap = alloca i8 *
+ %ap = alloca i8*
%ap2 = bitcast i8** %ap to i8*
call void @llvm.va_start(i8* %ap2)
; Read a single integer argument
- %tmp = va_arg i8 ** %ap, i32
+ %tmp = va_arg i8** %ap, i32
; Demonstrate usage of llvm.va_copy and llvm.va_end
- %aq = alloca i8 *
+ %aq = alloca i8*
%aq2 = bitcast i8** %aq to i8*
- call void @llvm.va_copy(i8 *%aq2, i8* %ap2)
+ call void @llvm.va_copy(i8* %aq2, i8* %ap2)
call void @llvm.va_end(i8* %aq2)
; Stop processing of arguments.
</pre>
</div>
+</div>
+
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection">
<a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
<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 the
-<tt>va_list</tt> element the argument points to, so that the next call to
+<tt>va_list</tt> element to which the argument points, so that the next call to
<tt>va_arg</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>
+last argument of the function as the compiler can figure that out.</p>
</div>
<pre> declare void @llvm.va_end(i8* <arglist>)<br></pre>
<h5>Overview:</h5>
-<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt><arglist></tt>
+<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*<arglist></tt>,
which has been initialized previously with <tt><a href="#int_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>
+<p>The argument is a pointer to 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="#int_va_start"><tt>llvm.va_start</tt></a> and <a
- href="#int_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
-with calls to <tt>llvm.va_end</tt>.</p>
+macro available in C. In a target-dependent way, it destroys the
+<tt>va_list</tt> element to which the argument points. Calls to <a
+href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
+<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
+<tt>llvm.va_end</tt>.</p>
</div>
<h5>Overview:</h5>
-<p>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.va_copy</tt>' intrinsic copies the current argument position
+from the source argument list to the destination argument list.</p>
<h5>Arguments:</h5>
<h5>Semantics:</h5>
-<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 destination list. This intrinsic is necessary
-because the <tt><a href="#int_va_start">llvm.va_start</a></tt> intrinsic may be
-arbitrarily complex and require memory allocation, for example.</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 destination <tt>va_list</tt> element. This
+intrinsic is necessary because the <tt><a href="#int_va_start">
+llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
+example, memory allocation.</p>
</div>
<h5>Syntax:</h5>
<pre>
- declare void @llvm.gcroot(<ty>** %ptrloc, <ty2>* %metadata)
+ declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
</pre>
<h5>Overview:</h5>
<h5>Syntax:</h5>
<pre>
- declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
+ declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
</pre>
<h5>Overview:</h5>
<h5>Syntax:</h5>
<pre>
- declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
+ declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
</pre>
<h5>Overview:</h5>
<h5>Syntax:</h5>
<pre>
- declare i8 *@llvm.frameaddress(i32 <level>)
+ declare i8 *@llvm.frameaddress(i32 <level>)
</pre>
<h5>Overview:</h5>
<h5>Syntax:</h5>
<pre>
- declare i8 *@llvm.stacksave()
+ declare i8 *@llvm.stacksave()
</pre>
<h5>Overview:</h5>
<h5>Syntax:</h5>
<pre>
- declare void @llvm.prefetch(i8 * <address>,
- i32 <rw>, i32 <locality>)
+ declare void @llvm.prefetch(i8* <address>, i32 <rw>, i32 <locality>)
</pre>
<h5>Overview:</h5>
<h5>Syntax:</h5>
<pre>
- declare void @llvm.pcmarker( i32 <id> )
+ declare void @llvm.pcmarker(i32 <id>)
</pre>
<h5>Overview:</h5>
<div class="doc_text">
<h5>Syntax:</h5>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
+floating point type. Not all targets support all types however.
<pre>
- declare float @llvm.sqrt.f32(float %Val)
- declare double @llvm.sqrt.f64(double %Val)
+ declare float @llvm.sqrt.f32(float %Val)
+ declare double @llvm.sqrt.f64(double %Val)
+ declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
+ declare fp128 @llvm.sqrt.f128(fp128 %Val)
+ declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
</pre>
<h5>Overview:</h5>
<h5>Semantics:</h5>
<p>
-This function returns the sqrt of the specified operand if it is a positive
+This function returns the sqrt of the specified operand if it is a nonnegative
floating point number.
</p>
</div>
<div class="doc_text">
<h5>Syntax:</h5>
+<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
+floating point type. Not all targets support all types however.
<pre>
- declare float @llvm.powi.f32(float %Val, i32 %power)
- declare double @llvm.powi.f64(double %Val, i32 %power)
+ declare float @llvm.powi.f32(float %Val, i32 %power)
+ declare double @llvm.powi.f64(double %Val, i32 %power)
+ declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
+ declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
+ declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
</pre>
<h5>Overview:</h5>
<h5>Syntax:</h5>
<p>This is an overloaded intrinsic function. You can use bswap on any integer
-type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix
-that includes the type for the result and the operand.
+type that is an even number of bytes (i.e. BitWidth % 16 == 0).
<pre>
- declare i16 @llvm.bswap.i16.i16(i16 <id>)
- declare i32 @llvm.bswap.i32.i32(i32 <id>)
- declare i64 @llvm.bswap.i64.i64(i64 <id>)
+ declare i16 @llvm.bswap.i16(i16 <id>)
+ declare i32 @llvm.bswap.i32(i32 <id>)
+ declare i64 @llvm.bswap.i64(i64 <id>)
</pre>
<h5>Overview:</h5>
<h5>Semantics:</h5>
<p>
-The <tt>llvm.bswap.16.i16</tt> intrinsic returns an i16 value that has the high
+The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
intrinsic returns an i32 value that has the four bytes of the input i32
swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
-i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>,
-<tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to
+i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
+<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
</p>
<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
width. Not all targets support all bit widths however.
<pre>
- declare i32 @llvm.ctpop.i8 (i8 <src>)
- declare i32 @llvm.ctpop.i16(i16 <src>)
+ declare i8 @llvm.ctpop.i8 (i8 <src>)
+ declare i16 @llvm.ctpop.i16(i16 <src>)
declare i32 @llvm.ctpop.i32(i32 <src>)
- declare i32 @llvm.ctpop.i64(i64 <src>)
- declare i32 @llvm.ctpop.i256(i256 <src>)
+ declare i64 @llvm.ctpop.i64(i64 <src>)
+ declare i256 @llvm.ctpop.i256(i256 <src>)
</pre>
<h5>Overview:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
integer bit width. Not all targets support all bit widths however.
<pre>
- declare i32 @llvm.ctlz.i8 (i8 <src>)
- declare i32 @llvm.ctlz.i16(i16 <src>)
+ declare i8 @llvm.ctlz.i8 (i8 <src>)
+ declare i16 @llvm.ctlz.i16(i16 <src>)
declare i32 @llvm.ctlz.i32(i32 <src>)
- declare i32 @llvm.ctlz.i64(i64 <src>)
- declare i32 @llvm.ctlz.i256(i256 <src>)
+ declare i64 @llvm.ctlz.i64(i64 <src>)
+ declare i256 @llvm.ctlz.i256(i256 <src>)
</pre>
<h5>Overview:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
integer bit width. Not all targets support all bit widths however.
<pre>
- declare i32 @llvm.cttz.i8 (i8 <src>)
- declare i32 @llvm.cttz.i16(i16 <src>)
+ declare i8 @llvm.cttz.i8 (i8 <src>)
+ declare i16 @llvm.cttz.i16(i16 <src>)
declare i32 @llvm.cttz.i32(i32 <src>)
- declare i32 @llvm.cttz.i64(i64 <src>)
- declare i32 @llvm.cttz.i256(i256 <src>)
+ declare i64 @llvm.cttz.i64(i64 <src>)
+ declare i256 @llvm.cttz.i256(i256 <src>)
</pre>
<h5>Overview:</h5>
<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
on any integer bit width.
<pre>
- declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit)
- declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit)
+ declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
+ declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
</pre>
<h5>Overview:</h5>
<li>A mask of the retained bits is created by shifting a -1 value.</li>
<li>The mask is ANDed with <tt>%val</tt> to produce the result.
</ol>
-<p>In reverse mode, a similar computation is made except that:</p>
-<ol>
- <li>The bits selected wrap around to include both the highest and lowest bits.
- For example, part.select(i16 X, 4, 7) selects bits from X with a mask of
- 0x00F0 (forwards case) while part.select(i16 X, 8, 3) selects bits from X
- with a mask of 0xFF0F.</li>
- <li>The bits returned in the reverse case are reversed. So, if X has the value
- 0x6ACF and we apply part.select(i16 X, 8, 3) to it, we get back the value
- 0x0A6F.</li>
-</ol>
+<p>In reverse mode, a similar computation is made except that the bits are
+returned in the reverse order. So, for example, if <tt>X</tt> has the value
+<tt>i16 0x0ACF (101011001111)</tt> and we apply
+<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
+<tt>i16 0x0026 (000000100110)</tt>.</p>
</div>
<div class="doc_subsubsection">
<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
on any integer bit width.
<pre>
- declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
- declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
+ declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
+ declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
</pre>
<h5>Overview:</h5>
are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
to the <tt>%hi</tt>th bit.
-<p>In reverse mode, a similar computation is made except that the bits replaced
-wrap around to include both the highest and lowest bits. For example, if a
-16 bit value is being replaced then <tt>%lo=8</tt> and <tt>%hi=4</tt> would
-cause these bits to be set: <tt>0xFF1F</tt>.</p>
+<p>In reverse mode, a similar computation is made except that the bits are
+reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
+<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
<h5>Examples:</h5>
<pre>
llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F
- llvm.part.set(0xFFFF, 0, 7, 4) -> 0x0060
- llvm.part.set(0xFFFF, 0, 8, 3) -> 0x00F0
+ llvm.part.set(0xFFFF, 0, 7, 4) -> 0xFF0F
+ llvm.part.set(0xFFFF, 1, 7, 4) -> 0xFF8F
+ llvm.part.set(0xFFFF, F, 8, 3) -> 0xFFE7
llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07
</pre>
</div>
Handling</a> document. </p>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_trampoline">Trampoline Intrinsic</a>
+</div>
+
+<div class="doc_text">
+<p>
+ This intrinsic makes it possible to excise one parameter, marked with
+ the <tt>nest</tt> attribute, from a function. The result is a callable
+ function pointer lacking the nest parameter - the caller does not need
+ to provide a value for it. Instead, the value to use is stored in
+ advance in a "trampoline", a block of memory usually allocated
+ on the stack, which also contains code to splice the nest value into the
+ argument list. This is used to implement the GCC nested function address
+ extension.
+</p>
+<p>
+ For example, if the function is
+ <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
+ pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
+<pre>
+ %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
+ %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
+ %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
+ %fp = bitcast i8* %p to i32 (i32, i32)*
+</pre>
+ <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
+ to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
+</div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre>
+declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>)
+</pre>
+<h5>Overview:</h5>
+<p>
+ This fills the memory pointed to by <tt>tramp</tt> with code
+ and returns a function pointer suitable for executing it.
+</p>
+<h5>Arguments:</h5>
+<p>
+ The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
+ pointers. The <tt>tramp</tt> argument must point to a sufficiently large
+ and sufficiently aligned block of memory; this memory is written to by the
+ intrinsic. Note that the size and the alignment are target-specific - LLVM
+ currently provides no portable way of determining them, so a front-end that
+ generates this intrinsic needs to have some target-specific knowledge.
+ The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
+</p>
+<h5>Semantics:</h5>
+<p>
+ The block of memory pointed to by <tt>tramp</tt> is filled with target
+ dependent code, turning it into a function. A pointer to this function is
+ returned, but needs to be bitcast to an
+ <a href="#int_trampoline">appropriate function pointer type</a>
+ before being called. The new function's signature is the same as that of
+ <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
+ removed. At most one such <tt>nest</tt> argument is allowed, and it must be
+ of pointer type. Calling the new function is equivalent to calling
+ <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
+ missing <tt>nest</tt> argument. If, after calling
+ <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
+ modified, then the effect of any later call to the returned function pointer is
+ undefined.
+</p>
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_general">General Intrinsics</a>
+</div>
+
+<div class="doc_text">
+<p> This class of intrinsics is designed to be generic and has
+no specific purpose. </p>
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+ declare void @llvm.var.annotation(i8* <val>, i8* <str>, i8* <str>, i32 <int> )
+</pre>
+
+<h5>Overview:</h5>
+
+<p>
+The '<tt>llvm.var.annotation</tt>' intrinsic
+</p>
+
+<h5>Arguments:</h5>
+
+<p>
+The first argument is a pointer to a value, the second is a pointer to a
+global string, the third is a pointer to a global string which is the source
+file name, and the last argument is the line number.
+</p>
+
+<h5>Semantics:</h5>
+
+<p>
+This intrinsic allows annotation of local variables with arbitrary strings.
+This can be useful for special purpose optimizations that want to look for these
+ annotations. These have no other defined use, they are ignored by code
+ generation and optimization.
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
+any integer bit width.
+</p>
+<pre>
+ declare i8 @llvm.annotation.i8(i8 <val>, i8* <str>, i8* <str>, i32 <int> )
+ declare i16 @llvm.annotation.i16(i16 <val>, i8* <str>, i8* <str>, i32 <int> )
+ declare i32 @llvm.annotation.i32(i32 <val>, i8* <str>, i8* <str>, i32 <int> )
+ declare i64 @llvm.annotation.i64(i64 <val>, i8* <str>, i8* <str>, i32 <int> )
+ declare i256 @llvm.annotation.i256(i256 <val>, i8* <str>, i8* <str>, i32 <int> )
+</pre>
+
+<h5>Overview:</h5>
+
+<p>
+The '<tt>llvm.annotation</tt>' intrinsic.
+</p>
+
+<h5>Arguments:</h5>
+
+<p>
+The first argument is an integer value (result of some expression),
+the second is a pointer to a global string, the third is a pointer to a global
+string which is the source file name, and the last argument is the line number.
+It returns the value of the first argument.
+</p>
+
+<h5>Semantics:</h5>
+
+<p>
+This intrinsic allows annotations to be put on arbitrary expressions
+with arbitrary strings. This can be useful for special purpose optimizations
+that want to look for these annotations. These have no other defined use, they
+are ignored by code generation and optimization.
+</div>
<!-- *********************************************************************** -->
<hr>
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