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Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2<html><head><title>llvm Assembly Language Reference Manual</title></head>
3<body bgcolor=white>
4
5<table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
6<tr><td>&nbsp; <font size=+5 color="#EEEEFF" face="Georgia,Palatino,Times,Roman"><b>llvm Assembly Language Reference Manual</b></font></td>
7</tr></table>
8
9<ol>
10 <li><a href="#abstract">Abstract</a>
11 <li><a href="#introduction">Introduction</a>
12 <li><a href="#identifiers">Identifiers</a>
13 <li><a href="#typesystem">Type System</a>
14 <ol>
15 <li><a href="#t_primitive">Primitive Types</a>
16 <ol>
17 <li><a href="#t_classifications">Type Classifications</a>
18 </ol>
19 <li><a href="#t_derived">Derived Types</a>
20 <ol>
21 <li><a href="#t_array" >Array Type</a>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]22 <li><a href="#t_function">Function Type</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]23 <li><a href="#t_pointer">Pointer Type</a>
24 <li><a href="#t_struct" >Structure Type</a>
25 <li><a href="#t_packed" >Packed Type</a>
26 </ol>
27 </ol>
28 <li><a href="#highlevel">High Level Structure</a>
29 <ol>
30 <li><a href="#modulestructure">Module Structure</a>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]31 <li><a href="#globalvars">Global Variables</a>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]32 <li><a href="#functionstructure">Function Structure</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]33 </ol>
34 <li><a href="#instref">Instruction Reference</a>
35 <ol>
36 <li><a href="#terminators">Terminator Instructions</a>
37 <ol>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]38 <li><a href="#i_ret" >'<tt>ret</tt>' Instruction</a>
39 <li><a href="#i_br" >'<tt>br</tt>' Instruction</a>
40 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a>
41 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]42 </ol>
43 <li><a href="#unaryops">Unary Operations</a>
44 <ol>
45 <li><a href="#i_not" >'<tt>not</tt>' Instruction</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]46 </ol>
47 <li><a href="#binaryops">Binary Operations</a>
48 <ol>
49 <li><a href="#i_add" >'<tt>add</tt>' Instruction</a>
50 <li><a href="#i_sub" >'<tt>sub</tt>' Instruction</a>
51 <li><a href="#i_mul" >'<tt>mul</tt>' Instruction</a>
52 <li><a href="#i_div" >'<tt>div</tt>' Instruction</a>
53 <li><a href="#i_rem" >'<tt>rem</tt>' Instruction</a>
54 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a>
55 </ol>
56 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
57 <ol>
58 <li><a href="#i_and">'<tt>and</tt>' Instruction</a>
59 <li><a href="#i_or" >'<tt>or</tt>' Instruction</a>
60 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a>
61 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a>
62 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a>
63 </ol>
64 <li><a href="#memoryops">Memory Access Operations</a>
65 <ol>
66 <li><a href="#i_malloc" >'<tt>malloc</tt>' Instruction</a>
67 <li><a href="#i_free" >'<tt>free</tt>' Instruction</a>
68 <li><a href="#i_alloca" >'<tt>alloca</tt>' Instruction</a>
69 <li><a href="#i_load" >'<tt>load</tt>' Instruction</a>
70 <li><a href="#i_store" >'<tt>store</tt>' Instruction</a>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]71 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]72 </ol>
73 <li><a href="#otherops">Other Operations</a>
74 <ol>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]75 <li><a href="#i_phi" >'<tt>phi</tt>' Instruction</a>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]76 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]77 <li><a href="#i_call" >'<tt>call</tt>' Instruction</a>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]78 </ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]79 </ol>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]80<!--
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]81 <li><a href="#related">Related Work</a>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]82-->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]83</ol>
84
85
86<!-- *********************************************************************** -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]87<p><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
88<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]89<a name="abstract">Abstract
90</b></font></td></tr></table><ul>
91<!-- *********************************************************************** -->
92
93<blockquote>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]94 This document is a reference manual for the LLVM assembly language. LLVM is
95 an SSA based representation that provides type safety, low level operations,
96 flexibility, and the capability of representing 'all' high level languages
97 cleanly. It is the common code representation used throughout all phases of
98 the LLVM compilation strategy.
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]99</blockquote>
100
101
102
103
104<!-- *********************************************************************** -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]105</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
106<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]107<a name="introduction">Introduction
108</b></font></td></tr></table><ul>
109<!-- *********************************************************************** -->
110
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]111The LLVM code representation is designed to be used in three different forms: as
112an in-memory compiler IR, as an on-disk bytecode representation, suitable for
113fast loading by a dynamic compiler, and as a human readable assembly language
114representation. This allows LLVM to provide a powerful intermediate
115representation for efficient compiler transformations and analysis, while
116providing a natural means to debug and visualize the transformations. The three
117different forms of LLVM are all equivalent. This document describes the human
118readable representation and notation.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]119
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]120The LLVM representation aims to be a light weight and low level while being
121expressive, type safe, and extensible at the same time. It aims to be a
122"universal IR" of sorts, by being at a low enough level that high level ideas
123may be cleanly mapped to it (similar to how microprocessors are "universal
124IR's", allowing many source languages to be mapped to them). By providing type
125safety, LLVM can be used as the target of optimizations: for example, through
126pointer analysis, it can be proven that a C automatic variable is never accessed
127outside of the current function... allowing it to be promoted to a simple SSA
128value instead of a memory location.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]129
130<!-- _______________________________________________________________________ -->
131</ul><a name="wellformed"><h4><hr size=0>Well Formedness</h4><ul>
132
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]133It is important to note that this document describes 'well formed' llvm assembly
134language. There is a difference between what the parser accepts and what is
135considered 'well formed'. For example, the following instruction is
136syntactically okay, but not well formed:<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]137
138<pre>
139 %x = <a href="#i_add">add</a> int 1, %x
140</pre>
141
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]142...because the definition of %x does not dominate all of its uses. The LLVM
143infrastructure provides a verification pass that may be used to verify that an
144LLVM module is well formed. This pass is automatically run by the parser after
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]145parsing input assembly, and by the optimizer before it outputs bytecode. The
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]146violations pointed out by the verifier pass indicate bugs in transformation
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]147passes or input to the parser.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]148
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]149<!-- Describe the typesetting conventions here. -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]150
151
152<!-- *********************************************************************** -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]153</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
154<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]155<a name="identifiers">Identifiers
156</b></font></td></tr></table><ul>
157<!-- *********************************************************************** -->
158
159LLVM uses three different forms of identifiers, for different purposes:<p>
160
161<ol>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]162<li>Numeric constants are represented as you would expect: 12, -3 123.421, etc. Floating point constants have an optional hexidecimal notation.
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]163<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>'.
164<li>Unnamed values are represented as an unsigned numeric value with a '%' prefix. For example, %12, %2, %44.
165</ol><p>
166
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]167LLVM requires the values start with a '%' sign for two reasons: Compilers don't
168need to worry about name clashes with reserved words, and the set of reserved
169words may be expanded in the future without penalty. Additionally, unnamed
170identifiers allow a compiler to quickly come up with a temporary variable
171without having to avoid symbol table conflicts.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]172
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]173Reserved words in LLVM are very similar to reserved words in other languages.
174There are keywords for different opcodes ('<tt><a href="#i_add">add</a></tt>',
175'<tt><a href="#i_cast">cast</a></tt>', '<tt><a href="#i_ret">ret</a></tt>',
176etc...), for primitive type names ('<tt><a href="#t_void">void</a></tt>',
177'<tt><a href="#t_uint">uint</a></tt>', etc...), and others. These reserved
178words cannot conflict with variable names, because none of them start with a '%'
179character.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]180
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]181Here is an example of LLVM code to multiply the integer variable '<tt>%X</tt>'
182by 8:<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]183
184The easy way:
185<pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]186 %result = <a href="#i_mul">mul</a> uint %X, 8
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]187</pre>
188
189After strength reduction:
190<pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]191 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]192</pre>
193
194And the hard way:
195<pre>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]196 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
197 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]198 %result = <a href="#i_add">add</a> uint %1, %1
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]199</pre>
200
201This last way of multiplying <tt>%X</tt> by 8 illustrates several important lexical features of LLVM:<p>
202
203<ol>
204<li>Comments are delimited with a '<tt>;</tt>' and go until the end of line.
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]205<li>Unnamed temporaries are created when the result of a computation is not
206 assigned to a named value.
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]207<li>Unnamed temporaries are numbered sequentially
208</ol><p>
209
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]210...and it also show a convention that we follow in this document. When
211demonstrating instructions, we will follow an instruction with a comment that
212defines the type and name of value produced. Comments are shown in italic
213text.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]214
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]215The one unintuitive notation for constants is the optional hexidecimal form of
216floating point constants. For example, the form '<tt>double
2170x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
2184.5e+15</tt>' which is also supported by the parser. The only time hexadecimal
219floating point constants are useful (and the only time that they are generated
220by the disassembler) is when an FP constant has to be emitted that is not
221representable as a decimal floating point number exactly. For example, NaN's,
222infinities, and other special cases are represented in their IEEE hexadecimal
223format so that assembly and disassembly do not cause any bits to change in the
224constants.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]225
226
227<!-- *********************************************************************** -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]228</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
229<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]230<a name="typesystem">Type System
231</b></font></td></tr></table><ul>
232<!-- *********************************************************************** -->
233
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]234The LLVM type system is one of the most important features of the intermediate
235representation. Being strongly typed enables a number of optimizations to be
236performed on the IR directly, without having to do extra analyses on the side
237before the transformation. A strong type system makes it easier to read the
238generated code and enables novel analyses and transformations that are not
239feasible to perform on normal three address code representations.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]240
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]241<!-- The written form for the type system was heavily influenced by the
242syntactic problems with types in the C language<sup><a
243href="#rw_stroustrup">1</a></sup>.<p> -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]244
245
246
247<!-- ======================================================================= -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]248</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
249<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]250<a name="t_primitive">Primitive Types
251</b></font></td></tr></table><ul>
252
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]253The primitive types are the fundemental building blocks of the LLVM system. The
254current set of primitive types are as follows:<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]255
256<table border=0 align=center><tr><td>
257
258<table border=1 cellspacing=0 cellpadding=4 align=center>
259<tr><td><tt>void</tt></td> <td>No value</td></tr>
260<tr><td><tt>ubyte</tt></td> <td>Unsigned 8 bit value</td></tr>
261<tr><td><tt>ushort</tt></td><td>Unsigned 16 bit value</td></tr>
262<tr><td><tt>uint</tt></td> <td>Unsigned 32 bit value</td></tr>
263<tr><td><tt>ulong</tt></td> <td>Unsigned 64 bit value</td></tr>
264<tr><td><tt>float</tt></td> <td>32 bit floating point value</td></tr>
265<tr><td><tt>label</tt></td> <td>Branch destination</td></tr>
266</table>
267
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]268</td><td valign=top>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]269
270<table border=1 cellspacing=0 cellpadding=4 align=center>
271<tr><td><tt>bool</tt></td> <td>True or False value</td></tr>
272<tr><td><tt>sbyte</tt></td> <td>Signed 8 bit value</td></tr>
273<tr><td><tt>short</tt></td> <td>Signed 16 bit value</td></tr>
274<tr><td><tt>int</tt></td> <td>Signed 32 bit value</td></tr>
275<tr><td><tt>long</tt></td> <td>Signed 64 bit value</td></tr>
276<tr><td><tt>double</tt></td><td>64 bit floating point value</td></tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]277</table>
278
279</td></tr></table><p>
280
281
282
283<!-- _______________________________________________________________________ -->
284</ul><a name="t_classifications"><h4><hr size=0>Type Classifications</h4><ul>
285
286These different primitive types fall into a few useful classifications:<p>
287
288<table border=1 cellspacing=0 cellpadding=4 align=center>
289<tr><td><a name="t_signed">signed</td> <td><tt>sbyte, short, int, long, float, double</tt></td></tr>
290<tr><td><a name="t_unsigned">unsigned</td><td><tt>ubyte, ushort, uint, ulong</tt></td></tr>
291<tr><td><a name="t_integral">integral</td><td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td></tr>
292<tr><td><a name="t_floating">floating point</td><td><tt>float, double</tt></td></tr>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]293<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>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]294</table><p>
295
296
297
298
299
300<!-- ======================================================================= -->
301</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
302<a name="t_derived">Derived Types
303</b></font></td></tr></table><ul>
304
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]305The real power in LLVM comes from the derived types in the system. This is what
306allows a programmer to represent arrays, functions, pointers, and other useful
307types. Note that these derived types may be recursive: For example, it is
308possible to have a two dimensional array.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]309
310
311
312<!-- _______________________________________________________________________ -->
313</ul><a name="t_array"><h4><hr size=0>Array Type</h4><ul>
314
315<h5>Overview:</h5>
316
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]317The array type is a very simple derived type that arranges elements sequentially
318in memory. The array type requires a size (number of elements) and an
319underlying data type.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]320
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]321<h5>Syntax:</h5>
322<pre>
323 [&lt;# elements&gt; x &lt;elementtype&gt;]
324</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]325
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]326The number of elements is a constant integer value, elementtype may be any type
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]327with a size.<p>
328
329<h5>Examples:</h5>
330<ul>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]331 <tt>[40 x int ]</tt>: Array of 40 integer values.<br>
332 <tt>[41 x int ]</tt>: Array of 41 integer values.<br>
333 <tt>[40 x uint]</tt>: Array of 40 unsigned integer values.<p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]334</ul>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]335
336Here are some examples of multidimensional arrays:<p>
337<ul>
338<table border=0 cellpadding=0 cellspacing=0>
339<tr><td><tt>[3 x [4 x int]]</tt></td><td>: 3x4 array integer values.</td></tr>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]340<tr><td><tt>[12 x [10 x float]]</tt></td><td>: 2x10 array of single precision floating point values.</td></tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]341<tr><td><tt>[2 x [3 x [4 x uint]]]</tt></td><td>: 2x3x4 array of unsigned integer values.</td></tr>
342</table>
343</ul>
344
345
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]346<!-- _______________________________________________________________________ -->
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]347</ul><a name="t_function"><h4><hr size=0>Function Type</h4><ul>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]348
349<h5>Overview:</h5>
350
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]351The function type can be thought of as a function signature. It consists of a
352return type and a list of formal parameter types. Function types are usually
353used when to build virtual function tables (which are structures of pointers to
354functions), for indirect function calls, and when defining a function.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]355
356<h5>Syntax:</h5>
357<pre>
358 &lt;returntype&gt; (&lt;parameter list&gt;)
359</pre>
360
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]361Where '<tt>&lt;parameter list&gt;</tt>' is a comma seperated list of type
362specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
363which indicates that the function takes a variable number of arguments. Note
364that there currently is no way to define a function in LLVM that takes a
365variable number of arguments, but it is possible to <b>call</b> a function that
366is vararg.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]367
368<h5>Examples:</h5>
369<ul>
370<table border=0 cellpadding=0 cellspacing=0>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]371
372<tr><td><tt>int (int)</tt></td><td>: function taking an <tt>int</tt>, returning
373an <tt>int</tt></td></tr>
374
375<tr><td><tt>float (int, int *) *</tt></td><td>: <a href="#t_pointer">Pointer</a>
376to a function that takes an <tt>int</tt> and a <a href="#t_pointer">pointer</a>
377to <tt>int</tt>, returning <tt>float</tt>.</td></tr>
378
379<tr><td><tt>int (sbyte *, ...)</tt></td><td>: A vararg function that takes at
380least one <a href="#t_pointer">pointer</a> to <tt>sbyte</tt> (signed char in C),
381which returns an integer. This is the signature for <tt>printf</tt> in
382LLVM.</td></tr>
383
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]384</table>
385</ul>
386
387
388
389<!-- _______________________________________________________________________ -->
390</ul><a name="t_struct"><h4><hr size=0>Structure Type</h4><ul>
391
392<h5>Overview:</h5>
393
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]394The structure type is used to represent a collection of data members together in
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]395memory. The packing of the field types is defined to match the ABI of the
396underlying processor. The elements of a structure may be any type that has a
397size.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]398
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]399Structures are accessed using '<tt><a href="#i_load">load</a></tt> and '<tt><a
400href="#i_store">store</a></tt>' by getting a pointer to a field with the '<tt><a
401href="#i_getelementptr">getelementptr</a></tt>' instruction.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]402
403<h5>Syntax:</h5>
404<pre>
405 { &lt;type list&gt; }
406</pre>
407
408
409<h5>Examples:</h5>
410<table border=0 cellpadding=0 cellspacing=0>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]411
412<tr><td><tt>{ int, int, int }</tt></td><td>: a triple of three <tt>int</tt>
413values</td></tr>
414
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]415<tr><td><tt>{ float, int (int) * }</tt></td><td>: A pair, where the first
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]416element is a <tt>float</tt> and the second element is a <a
417href="#t_pointer">pointer</a> to a <a href="t_function">function</a> that takes
418an <tt>int</tt>, returning an <tt>int</tt>.</td></tr>
419
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]420</table>
421
422
423<!-- _______________________________________________________________________ -->
424</ul><a name="t_pointer"><h4><hr size=0>Pointer Type</h4><ul>
425
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]426<h5>Overview:</h5>
427
428As in many languages, the pointer type represents a pointer or reference to
429another object, which must live in memory.<p>
430
431<h5>Syntax:</h5>
432<pre>
433 &lt;type&gt; *
434</pre>
435
436<h5>Examples:</h5>
437
438<table border=0 cellpadding=0 cellspacing=0>
439
440<tr><td><tt>[4x int]*</tt></td><td>: <a href="#t_pointer">pointer</a> to <a
441href="#t_array">array</a> of four <tt>int</tt> values</td></tr>
442
443<tr><td><tt>int (int *) *</tt></td><td>: A <a href="#t_pointer">pointer</a> to a
444<a href="t_function">function</a> that takes an <tt>int</tt>, returning an
445<tt>int</tt>.</td></tr>
446
447</table>
448<p>
449
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]450
451<!-- _______________________________________________________________________ -->
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]452<!--
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]453</ul><a name="t_packed"><h4><hr size=0>Packed Type</h4><ul>
454
455Mention/decide that packed types work with saturation or not. Maybe have a packed+saturated type in addition to just a packed type.<p>
456
457Packed types should be 'nonsaturated' because standard data types are not saturated. Maybe have a saturated packed type?<p>
458
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]459-->
460
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]461
462<!-- *********************************************************************** -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]463</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
464<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]465<a name="highlevel">High Level Structure
466</b></font></td></tr></table><ul>
467<!-- *********************************************************************** -->
468
469
470<!-- ======================================================================= -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]471</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
472<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]473<a name="modulestructure">Module Structure
474</b></font></td></tr></table><ul>
475
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]476LLVM programs are composed of "Module"s, each of which is a translation unit of
477the input programs. Each module consists of functions, global variables, and
478symbol table entries. Modules may be combined together with the LLVM linker,
479which merges function (and global variable) definitions, resolves forward
480declarations, and merges symbol table entries. Here is an example of the "hello world" module:<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]481
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]482<pre>
483<i>; Declare the string constant as a global constant...</i>
484<a href="#identifiers">%.LC0</a> = <a href="#linkage_decl">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>
485
486<i>; Forward declaration of puts</i>
487<a href="#functionstructure">declare</a> int "puts"(sbyte*) <i>; int(sbyte*)* </i>
488
489<i>; Definition of main function</i>
490int "main"() { <i>; int()* </i>
491 <i>; Convert [13x sbyte]* to sbyte *...</i>
492 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, uint 0, uint 0 <i>; sbyte*</i>
493
494 <i>; Call puts function to write out the string to stdout...</i>
495 <a href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
496 <a href="#i_ret">ret</a> int 0
497}
498</pre>
499
500This example is made up of a <a href="#globalvars">global variable</a> named
501"<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and a
502<a href="#functionstructure">function definition</a> for "<tt>main</tt>".<p>
503
504<a name="linkage_decl">
505In general, a module is made up of a list of global values, where both functions
506and global variables are global values. Global values are represented by a
507pointer to a memory location (in this case, a pointer to an array of char, and a
508pointer to a function), and can be either "internal" or externally accessible
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]509(which corresponds to the static keyword in C, when used at global scope).<p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]510
511For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
512another module defined a "<tt>.LC0</tt>" variable and was linked with this one,
513one of the two would be renamed, preventing a collision. Since "<tt>main</tt>"
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]514and "<tt>puts</tt>" are external (i.e., lacking "<tt>internal</tt>"
515declarations), they are accessible outside of the current module. It is illegal
516for a function declaration to be "<tt>internal</tt>".<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]517
518
519<!-- ======================================================================= -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]520</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
521<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
522<a name="globalvars">Global Variables
523</b></font></td></tr></table><ul>
524
525Global variables define regions of memory allocated at compilation time instead
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]526of run-time. Global variables may optionally be initialized. A variable may
527be defined as a global "constant", which indicates that the contents of the
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]528variable will never be modified (opening options for optimization). Constants
529must always have an initial value.<p>
530
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]531As SSA values, global variables define pointer values that are in scope
532(i.e. they dominate) for all basic blocks in the program. Global variables
533always define a pointer to their "content" type because they describe a region
534of memory, and all memory objects in LLVM are accessed through pointers.<p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]535
536
537
538<!-- ======================================================================= -->
539</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
540<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]541<a name="functionstructure">Function Structure
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]542</b></font></td></tr></table><ul>
543
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]544LLVM functions definitions are composed of a (possibly empty) argument list, an
545opening curly brace, a list of basic blocks, and a closing curly brace. LLVM
546function declarations are defined with the "<tt>declare</tt>" keyword, a
547function name and a function signature.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]548
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]549A function definition contains a list of basic blocks, forming the CFG for the
550function. Each basic block may optionally start with a label (giving the basic
551block a symbol table entry), contains a list of instructions, and ends with a <a
552href="#terminators">terminator</a> instruction (such as a branch or function
553return).<p>
554
555The first basic block in program is special in two ways: it is immediately
556executed on entrance to the function, and it is not allowed to have predecessor
557basic blocks (i.e. there can not be any branches to the entry block of a
558function).<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]559
560
561<!-- *********************************************************************** -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]562</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
563<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]564<a name="instref">Instruction Reference
565</b></font></td></tr></table><ul>
566<!-- *********************************************************************** -->
567
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]568The LLVM instruction set consists of several different classifications of
569instructions: <a href="#terminators">terminator instructions</a>, a <a
570href="#unaryops">unary instruction</a>, <a href="#binaryops">binary
571instructions</a>, <a href="#memoryops">memory instructions</a>, and <a
572href="#otherops">other instructions</a>.<p>
573
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]574
575<!-- ======================================================================= -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]576</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
577<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]578<a name="terminators">Terminator Instructions
579</b></font></td></tr></table><ul>
580
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]581As mentioned <a href="#functionstructure">previously</a>, every basic block in a
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]582program ends with a "Terminator" instruction, which indicates which block should
583be executed after the current block is finished. These terminator instructions
584typically yield a '<tt>void</tt>' value: they produce control flow, not values
585(the one exception being the '<a href="#i_invoke"><tt>invoke</tt></a>'
586instruction).<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]587
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]588There are four different terminator instructions: the '<a
589href="#i_ret"><tt>ret</tt></a>' instruction, the '<a
590href="#i_br"><tt>br</tt></a>' instruction, the '<a
591href="#i_switch"><tt>switch</tt></a>' instruction, and the '<a
592href="#i_invoke"><tt>invoke</tt></a>' instruction.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]593
594
595<!-- _______________________________________________________________________ -->
596</ul><a name="i_ret"><h4><hr size=0>'<tt>ret</tt>' Instruction</h4><ul>
597
598<h5>Syntax:</h5>
599<pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]600 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
601 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]602</pre>
603
604<h5>Overview:</h5>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]605
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]606The '<tt>ret</tt>' instruction is used to return control flow (and a value) from
607a function, back to the caller.<p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]608
609There are two forms of the '<tt>ret</tt>' instructruction: one that returns a
610value and then causes control flow, and one that just causes control flow to
611occur.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]612
613<h5>Arguments:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]614
615The '<tt>ret</tt>' instruction may return any '<a href="#t_firstclass">first
616class</a>' type. Notice that a function is not <a href="#wellformed">well
617formed</a> if there exists a '<tt>ret</tt>' instruction inside of the function
618that returns a value that does not match the return type of the function.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]619
620<h5>Semantics:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]621
622When the '<tt>ret</tt>' instruction is executed, control flow returns back to
623the calling function's context. If the instruction returns a value, that value
624shall be propogated into the calling function's data space.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]625
626<h5>Example:</h5>
627<pre>
628 ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]629 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]630</pre>
631
632
633<!-- _______________________________________________________________________ -->
634</ul><a name="i_br"><h4><hr size=0>'<tt>br</tt>' Instruction</h4><ul>
635
636<h5>Syntax:</h5>
637<pre>
638 br bool &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
639 br label &lt;dest&gt; <i>; Unconditional branch</i>
640</pre>
641
642<h5>Overview:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]643
644The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
645different basic block in the current function. There are two forms of this
646instruction, corresponding to a conditional branch and an unconditional
647branch.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]648
649<h5>Arguments:</h5>
650
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]651The conditional branch form of the '<tt>br</tt>' instruction takes a single
652'<tt>bool</tt>' value and two '<tt>label</tt>' values. The unconditional form
653of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
654target.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]655
656<h5>Semantics:</h5>
657
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]658Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
659argument is evaluated. If the value is <tt>true</tt>, control flows to the
660'<tt>iftrue</tt>' '<tt>label</tt>' argument. If "cond" is <tt>false</tt>,
661control flows to the '<tt>iffalse</tt>' '<tt>label</tt>' argument.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]662
663<h5>Example:</h5>
664<pre>
665Test:
666 %cond = <a href="#i_setcc">seteq</a> int %a, %b
667 br bool %cond, label %IfEqual, label %IfUnequal
668IfEqual:
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]669 <a href="#i_ret">ret</a> int 1
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]670IfUnequal:
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]671 <a href="#i_ret">ret</a> int 0
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]672</pre>
673
674
675<!-- _______________________________________________________________________ -->
676</ul><a name="i_switch"><h4><hr size=0>'<tt>switch</tt>' Instruction</h4><ul>
677
678<h5>Syntax:</h5>
679<pre>
680 <i>; Definitions for lookup indirect branch</i>
681 %switchtype = type [&lt;anysize&gt; x { uint, label }]
682
683 <i>; Lookup indirect branch</i>
684 switch uint &lt;value&gt;, label &lt;defaultdest&gt;, %switchtype &lt;switchtable&gt;
685
686 <i>; Indexed indirect branch</i>
687 switch uint &lt;idxvalue&gt;, label &lt;defaultdest&gt;, [&lt;anysize&gt; x label] &lt;desttable&gt;
688</pre>
689
690<h5>Overview:</h5>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]691
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]692The '<tt>switch</tt>' instruction is used to transfer control flow to one of
693several different places. It is a generalization of the '<tt>br</tt>'
694instruction, allowing a branch to occur to one of many possible destinations.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]695
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]696The '<tt>switch</tt>' statement supports two different styles of indirect
697branching: lookup branching and indexed branching. Lookup branching is
698generally useful if the values to switch on are spread far appart, where index
699branching is useful if the values to switch on are generally dense.<p>
700
701The two different forms of the '<tt>switch</tt>' statement are simple hints to
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]702the underlying implementation. For example, the compiler may choose to
703implement a small indirect branch table as a series of predicated comparisons:
704if it is faster for the target architecture.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]705
706<h5>Arguments:</h5>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]707
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]708The lookup form of the '<tt>switch</tt>' instruction uses three parameters: a
709'<tt>uint</tt>' comparison value '<tt>value</tt>', a default '<tt>label</tt>'
710destination, and an array of pairs of comparison value constants and
711'<tt>label</tt>'s. The sized array must be a constant value.<p>
712
713The indexed form of the '<tt>switch</tt>' instruction uses three parameters: an
714'<tt>uint</tt>' index value, a default '<tt>label</tt>' and a sized array of
715'<tt>label</tt>'s. The '<tt>dests</tt>' array must be a constant array.
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]716
717<h5>Semantics:</h5>
718
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]719The lookup style switch statement specifies a table of values and destinations.
720When the '<tt>switch</tt>' instruction is executed, this table is searched for
721the given value. If the value is found, the corresponding destination is
722branched to. <p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]723
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]724The index branch form simply looks up a label element directly in a table and
725branches to it.<p>
726
727In either case, the compiler knows the static size of the array, because it is
728provided as part of the constant values type.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]729
730<h5>Example:</h5>
731<pre>
732 <i>; Emulate a conditional br instruction</i>
733 %Val = <a href="#i_cast">cast</a> bool %value to uint
734 switch uint %Val, label %truedest, [1 x label] [label %falsedest ]
735
736 <i>; Emulate an unconditional br instruction</i>
737 switch uint 0, label %dest, [ 0 x label] [ ]
738
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]739 <i>; Implement a jump table:</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]740 switch uint %val, label %otherwise, [3 x label] [ label %onzero,
741 label %onone,
742 label %ontwo ]
743
744</pre>
745
746
747
748<!-- _______________________________________________________________________ -->
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]749</ul><a name="i_invoke"><h4><hr size=0>'<tt>invoke</tt>' Instruction</h4><ul>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]750
751<h5>Syntax:</h5>
752<pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]753 &lt;result&gt; = invoke &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
754 to label &lt;normal label&gt; except label &lt;exception label&gt;
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]755</pre>
756
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]757<h5>Overview:</h5>
758
759The '<tt>invoke</tt>' instruction is used to cause control flow to transfer to a
760specified function, with the possibility of control flow transfer to either the
761'<tt>normal label</tt>' label or the '<tt>exception label</tt>'. The '<tt><a
762href="#i_call">call</a></tt>' instruction is closely related, but guarantees
763that control flow either never returns from the called function, or that it
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]764returns to the instruction following the '<tt><a href="#i_call">call</a></tt>'
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]765instruction.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]766
767<h5>Arguments:</h5>
768
769This instruction requires several arguments:<p>
770<ol>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]771
772<li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]773function value being invoked. In most cases, this is a direct function
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]774invocation, but indirect <tt>invoke</tt>'s are just as possible, branching off
775an arbitrary pointer to function value.<p>
776
777<li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
778function to be invoked.
779
780<li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]781signature argument types. If the function signature indicates the function
782accepts a variable number of arguments, the extra arguments can be specified.
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]783
784<li>'<tt>normal label</tt>': the label reached when the called function executes
785a '<tt><a href="#i_ret">ret</a></tt>' instruction.
786
787<li>'<tt>exception label</tt>': the label reached when an exception is thrown.
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]788</ol>
789
790<h5>Semantics:</h5>
791
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]792This instruction is designed to operate as a standard '<tt><a
793href="#i_call">call</a></tt>' instruction in most regards. The primary
794difference is that it associates a label with the function invocation that may
795be accessed via the runtime library provided by the execution environment. This
796instruction is used in languages with destructors to ensure that proper cleanup
797is performed in the case of either a <tt>longjmp</tt> or a thrown exception.
798Additionally, this is important for implementation of '<tt>catch</tt>' clauses
799in high-level languages that support them.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]800
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]801<!-- For a more comprehensive explanation of how this instruction is used, look in the llvm/docs/2001-05-18-ExceptionHandling.txt document.<p> -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]802
803<h5>Example:</h5>
804<pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]805 %retval = invoke int %Test(int 15)
806 to label %Continue except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]807</pre>
808
809
810
811<!-- ======================================================================= -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]812</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
813<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]814<a name="unaryops">Unary Operations
815</b></font></td></tr></table><ul>
816
817Unary operators are used to do a simple operation to a single value.<p>
818
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]819There is only one unary operator: the '<a href="#i_not"><tt>not</tt></a>' instruction.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]820
821
822<!-- _______________________________________________________________________ -->
823</ul><a name="i_not"><h4><hr size=0>'<tt>not</tt>' Instruction</h4><ul>
824
825<h5>Syntax:</h5>
826<pre>
827 &lt;result&gt; = not &lt;ty&gt; &lt;var&gt; <i>; yields {ty}:result</i>
828</pre>
829
830<h5>Overview:</h5>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]831The '<tt>not</tt>' instruction returns the bitwise complement of its operand.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]832
833<h5>Arguments:</h5>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]834The single argument to '<tt>not</tt>' must be of of <a href="#t_integral">integral</a> or bool type.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]835
836
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]837<h5>Semantics:</h5> The '<tt>not</tt>' instruction returns the bitwise
838complement (AKA ones complement) of an <a href="#t_integral">integral</a>
839type.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]840
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]841<pre>
842 &lt;result&gt; = xor bool true, &lt;var&gt; <i>; yields {bool}:result</i>
843</pre>
844
845<h5>Example:</h5>
846<pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]847 %x = not int 1 <i>; {int}:x is now equal to -2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]848 %x = not bool true <i>; {bool}:x is now equal to false</i>
849</pre>
850
851
852
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]853<!-- ======================================================================= -->
854</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0><tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
855<a name="binaryops">Binary Operations
856</b></font></td></tr></table><ul>
857
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]858Binary operators are used to do most of the computation in a program. They
859require two operands, execute an operation on them, and produce a single value.
860The result value of a binary operator is not neccesarily the same type as its
861operands.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]862
863There are several different binary operators:<p>
864
865
866<!-- _______________________________________________________________________ -->
867</ul><a name="i_add"><h4><hr size=0>'<tt>add</tt>' Instruction</h4><ul>
868
869<h5>Syntax:</h5>
870<pre>
871 &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
872</pre>
873
874<h5>Overview:</h5>
875The '<tt>add</tt>' instruction returns the sum of its two operands.<p>
876
877<h5>Arguments:</h5>
878The two arguments to the '<tt>add</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
879
880<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]881
882The value produced is the integral or floating point sum of the two operands.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]883
884<h5>Example:</h5>
885<pre>
886 &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
887</pre>
888
889
890<!-- _______________________________________________________________________ -->
891</ul><a name="i_sub"><h4><hr size=0>'<tt>sub</tt>' Instruction</h4><ul>
892
893<h5>Syntax:</h5>
894<pre>
895 &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
896</pre>
897
898<h5>Overview:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]899
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]900The '<tt>sub</tt>' instruction returns the difference of its two operands.<p>
901
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]902Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
903instruction present in most other intermediate representations.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]904
905<h5>Arguments:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]906
907The two arguments to the '<tt>sub</tt>' instruction must be either <a
908href="#t_integral">integral</a> or <a href="#t_floating">floating point</a>
909values. Both arguments must have identical types.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]910
911<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]912
913The value produced is the integral or floating point difference of the two
914operands.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]915
916<h5>Example:</h5>
917<pre>
918 &lt;result&gt; = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
919 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
920</pre>
921
922<!-- _______________________________________________________________________ -->
923</ul><a name="i_mul"><h4><hr size=0>'<tt>mul</tt>' Instruction</h4><ul>
924
925<h5>Syntax:</h5>
926<pre>
927 &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
928</pre>
929
930<h5>Overview:</h5>
931The '<tt>mul</tt>' instruction returns the product of its two operands.<p>
932
933<h5>Arguments:</h5>
934The two arguments to the '<tt>mul</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
935
936<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]937
938The value produced is the integral or floating point product of the two
939operands.<p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]940
941There is no signed vs unsigned multiplication. The appropriate action is taken
942based on the type of the operand. <p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]943
944
945<h5>Example:</h5>
946<pre>
947 &lt;result&gt; = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
948</pre>
949
950
951<!-- _______________________________________________________________________ -->
952</ul><a name="i_div"><h4><hr size=0>'<tt>div</tt>' Instruction</h4><ul>
953
954<h5>Syntax:</h5>
955<pre>
956 &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
957</pre>
958
959<h5>Overview:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]960
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]961The '<tt>div</tt>' instruction returns the quotient of its two operands.<p>
962
963<h5>Arguments:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]964
965The two arguments to the '<tt>div</tt>' instruction must be either <a
966href="#t_integral">integral</a> or <a href="#t_floating">floating point</a>
967values. Both arguments must have identical types.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]968
969<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]970
971The value produced is the integral or floating point quotient of the two
972operands.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]973
974<h5>Example:</h5>
975<pre>
976 &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
977</pre>
978
979
980<!-- _______________________________________________________________________ -->
981</ul><a name="i_rem"><h4><hr size=0>'<tt>rem</tt>' Instruction</h4><ul>
982
983<h5>Syntax:</h5>
984<pre>
985 &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
986</pre>
987
988<h5>Overview:</h5>
989The '<tt>rem</tt>' instruction returns the remainder from the division of its two operands.<p>
990
991<h5>Arguments:</h5>
992The two arguments to the '<tt>rem</tt>' instruction must be either <a href="#t_integral">integral</a> or <a href="#t_floating">floating point</a> values. Both arguments must have identical types.<p>
993
994<h5>Semantics:</h5>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]995
996This returns the <i>remainder</i> of a division (where the result has the same
997sign as the divisor), not the <i>modulus</i> (where the result has the same sign
998as the dividend) of a value. For more information about the difference, see: <a
999href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The Math
1000Forum</a>.<p>
1001
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1002<h5>Example:</h5>
1003<pre>
1004 &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1005</pre>
1006
1007
1008<!-- _______________________________________________________________________ -->
1009</ul><a name="i_setcc"><h4><hr size=0>'<tt>set<i>cc</i></tt>' Instructions</h4><ul>
1010
1011<h5>Syntax:</h5>
1012<pre>
1013 &lt;result&gt; = seteq &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1014 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1015 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1016 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1017 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1018 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1019</pre>
1020
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1021<h5>Overview:</h5> The '<tt>set<i>cc</i></tt>' family of instructions returns a
1022boolean value based on a comparison of their two operands.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1023
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1024<h5>Arguments:</h5> The two arguments to the '<tt>set<i>cc</i></tt>'
1025instructions must be of <a href="#t_firstclass">first class</a> or <a
1026href="#t_pointer">pointer</a> type (it is not possible to compare
1027'<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>' or '<tt>void</tt>'
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1028values, etc...). Both arguments must have identical types.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1029
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1030The '<tt>setlt</tt>', '<tt>setgt</tt>', '<tt>setle</tt>', and '<tt>setge</tt>'
1031instructions do not operate on '<tt>bool</tt>' typed arguments.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1032
1033<h5>Semantics:</h5>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1034
1035The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
1036both operands are equal.<br>
1037
1038The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
1039both operands are unequal.<br>
1040
1041The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
1042the first operand is less than the second operand.<br>
1043
1044The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
1045the first operand is greater than the second operand.<br>
1046
1047The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
1048the first operand is less than or equal to the second operand.<br>
1049
1050The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>' value if
1051the first operand is greater than or equal to the second operand.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1052
1053<h5>Example:</h5>
1054<pre>
1055 &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
1056 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1057 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1058 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1059 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1060 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1061</pre>
1062
1063
1064
1065<!-- ======================================================================= -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1066</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1067<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1068<a name="bitwiseops">Bitwise Binary Operations
1069</b></font></td></tr></table><ul>
1070
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1071Bitwise binary operators are used to do various forms of bit-twiddling in a
1072program. They are generally very efficient instructions, and can commonly be
1073strength reduced from other instructions. They require two operands, execute an
1074operation on them, and produce a single value. The resulting value of the
1075bitwise binary operators is always the same type as its first operand.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1076
1077<!-- _______________________________________________________________________ -->
1078</ul><a name="i_and"><h4><hr size=0>'<tt>and</tt>' Instruction</h4><ul>
1079
1080<h5>Syntax:</h5>
1081<pre>
1082 &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1083</pre>
1084
1085<h5>Overview:</h5>
1086The '<tt>and</tt>' instruction returns the bitwise logical and of its two operands.<p>
1087
1088<h5>Arguments:</h5>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1089
1090The two arguments to the '<tt>and</tt>' instruction must be either <a
1091href="#t_integral">integral</a> or <tt>bool</tt> values. Both arguments must
1092have identical types.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1093
1094
1095<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1096
1097The truth table used for the '<tt>and</tt>' instruction is:<p>
1098
1099<center><table border=0>
1100<tr><td>In0</td> <td>In1</td> <td>Out</td></tr>
1101<tr><td>0</td> <td>0</td> <td>0</td></tr>
1102<tr><td>0</td> <td>1</td> <td>0</td></tr>
1103<tr><td>1</td> <td>0</td> <td>0</td></tr>
1104<tr><td>1</td> <td>1</td> <td>1</td></tr>
1105</table></center><p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1106
1107
1108<h5>Example:</h5>
1109<pre>
1110 &lt;result&gt; = and int 4, %var <i>; yields {int}:result = 4 & %var</i>
1111 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1112 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1113</pre>
1114
1115
1116
1117<!-- _______________________________________________________________________ -->
1118</ul><a name="i_or"><h4><hr size=0>'<tt>or</tt>' Instruction</h4><ul>
1119
1120<h5>Syntax:</h5>
1121<pre>
1122 &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1123</pre>
1124
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1125<h5>Overview:</h5> The '<tt>or</tt>' instruction returns the bitwise logical
1126inclusive or of its two operands.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1127
1128<h5>Arguments:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1129
1130The two arguments to the '<tt>or</tt>' instruction must be either <a
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1131href="#t_integral">integral</a> or <tt>bool</tt> values. Both arguments must
1132have identical types.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1133
1134
1135<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1136
1137The truth table used for the '<tt>or</tt>' instruction is:<p>
1138
1139<center><table border=0>
1140<tr><td>In0</td> <td>In1</td> <td>Out</td></tr>
1141<tr><td>0</td> <td>0</td> <td>0</td></tr>
1142<tr><td>0</td> <td>1</td> <td>1</td></tr>
1143<tr><td>1</td> <td>0</td> <td>1</td></tr>
1144<tr><td>1</td> <td>1</td> <td>1</td></tr>
1145</table></center><p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1146
1147
1148<h5>Example:</h5>
1149<pre>
1150 &lt;result&gt; = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
1151 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1152 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1153</pre>
1154
1155
1156<!-- _______________________________________________________________________ -->
1157</ul><a name="i_xor"><h4><hr size=0>'<tt>xor</tt>' Instruction</h4><ul>
1158
1159<h5>Syntax:</h5>
1160<pre>
1161 &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1162</pre>
1163
1164<h5>Overview:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1165
1166The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of its
1167two operands.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1168
1169<h5>Arguments:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1170
1171The two arguments to the '<tt>xor</tt>' instruction must be either <a
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1172href="#t_integral">integral</a> or <tt>bool</tt> values. Both arguments must
1173have identical types.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1174
1175
1176<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1177
1178The truth table used for the '<tt>xor</tt>' instruction is:<p>
1179
1180<center><table border=0>
1181<tr><td>In0</td> <td>In1</td> <td>Out</td></tr>
1182<tr><td>0</td> <td>0</td> <td>0</td></tr>
1183<tr><td>0</td> <td>1</td> <td>1</td></tr>
1184<tr><td>1</td> <td>0</td> <td>1</td></tr>
1185<tr><td>1</td> <td>1</td> <td>0</td></tr>
1186</table></center><p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1187
1188
1189<h5>Example:</h5>
1190<pre>
1191 &lt;result&gt; = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
1192 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1193 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
1194</pre>
1195
1196
1197<!-- _______________________________________________________________________ -->
1198</ul><a name="i_shl"><h4><hr size=0>'<tt>shl</tt>' Instruction</h4><ul>
1199
1200<h5>Syntax:</h5>
1201<pre>
1202 &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
1203</pre>
1204
1205<h5>Overview:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1206
1207The '<tt>shl</tt>' instruction returns the first operand shifted to the left a
1208specified number of bits.
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1209
1210<h5>Arguments:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1211
1212The first argument to the '<tt>shl</tt>' instruction must be an <a
1213href="#t_integral">integral</a> type. The second argument must be an
1214'<tt>ubyte</tt>' type.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1215
1216<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1217
1218The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1219
1220
1221<h5>Example:</h5>
1222<pre>
1223 &lt;result&gt; = shl int 4, ubyte %var <i>; yields {int}:result = 4 << %var</i>
1224 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1225 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1226</pre>
1227
1228
1229<!-- _______________________________________________________________________ -->
1230</ul><a name="i_shr"><h4><hr size=0>'<tt>shr</tt>' Instruction</h4><ul>
1231
1232
1233<h5>Syntax:</h5>
1234<pre>
1235 &lt;result&gt; = shr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
1236</pre>
1237
1238<h5>Overview:</h5>
1239The '<tt>shr</tt>' instruction returns the first operand shifted to the right a specified number of bits.
1240
1241<h5>Arguments:</h5>
1242The first argument to the '<tt>shr</tt>' instruction must be an <a href="#t_integral">integral</a> type. The second argument must be an '<tt>ubyte</tt>' type.<p>
1243
1244<h5>Semantics:</h5>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1245
1246If the first argument is a <a href="#t_signed">signed</a> type, the most
1247significant bit is duplicated in the newly free'd bit positions. If the first
1248argument is unsigned, zero bits shall fill the empty positions.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1249
1250<h5>Example:</h5>
1251<pre>
1252 &lt;result&gt; = shr int 4, ubyte %var <i>; yields {int}:result = 4 >> %var</i>
1253 &lt;result&gt; = shr int 4, ubyte 1 <i>; yields {int}:result = 2</i>
1254 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
1255 &lt;result&gt; = shr int 4, ubyte 3 <i>; yields {int}:result = 0</i>
1256</pre>
1257
1258
1259
1260
1261
1262<!-- ======================================================================= -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1263</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1264<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1265<a name="memoryops">Memory Access Operations
1266</b></font></td></tr></table><ul>
1267
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1268Accessing memory in SSA form is, well, sticky at best. This section describes how to read, write, allocate and free memory in LLVM.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1269
1270
1271<!-- _______________________________________________________________________ -->
1272</ul><a name="i_malloc"><h4><hr size=0>'<tt>malloc</tt>' Instruction</h4><ul>
1273
1274<h5>Syntax:</h5>
1275<pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1276 &lt;result&gt; = malloc &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
1277 &lt;result&gt; = malloc &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1278</pre>
1279
1280<h5>Overview:</h5>
1281The '<tt>malloc</tt>' instruction allocates memory from the system heap and returns a pointer to it.<p>
1282
1283<h5>Arguments:</h5>
1284
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1285The the '<tt>malloc</tt>' instruction allocates
1286<tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
1287system, and returns a pointer of the appropriate type to the program. The
1288second form of the instruction is a shorter version of the first instruction
1289that defaults to allocating one element.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1290
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1291'<tt>type</tt>' must be a sized type<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1292
1293<h5>Semantics:</h5>
1294Memory is allocated, a pointer is returned.<p>
1295
1296<h5>Example:</h5>
1297<pre>
1298 %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
1299
1300 %size = <a href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1301 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1302 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1303</pre>
1304
1305
1306<!-- _______________________________________________________________________ -->
1307</ul><a name="i_free"><h4><hr size=0>'<tt>free</tt>' Instruction</h4><ul>
1308
1309<h5>Syntax:</h5>
1310<pre>
1311 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
1312</pre>
1313
1314
1315<h5>Overview:</h5>
1316The '<tt>free</tt>' instruction returns memory back to the unused memory heap, to be reallocated in the future.<p>
1317
1318
1319<h5>Arguments:</h5>
1320
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1321'<tt>value</tt>' shall be a pointer value that points to a value that was
1322allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1323
1324
1325<h5>Semantics:</h5>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1326
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1327Access to the memory pointed to by the pointer is not longer defined after this instruction executes.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1328
1329<h5>Example:</h5>
1330<pre>
1331 %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
1332 free [4 x ubyte]* %array
1333</pre>
1334
1335
1336<!-- _______________________________________________________________________ -->
1337</ul><a name="i_alloca"><h4><hr size=0>'<tt>alloca</tt>' Instruction</h4><ul>
1338
1339<h5>Syntax:</h5>
1340<pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1341 &lt;result&gt; = alloca &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
1342 &lt;result&gt; = alloca &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1343</pre>
1344
1345<h5>Overview:</h5>
1346
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1347The '<tt>alloca</tt>' instruction allocates memory on the current stack frame of
1348the procedure that is live until the current function returns to its caller.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1349
1350<h5>Arguments:</h5>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1351
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1352The the '<tt>alloca</tt>' instruction allocates
1353<tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the runtime stack,
1354returning a pointer of the appropriate type to the program. The second form of
1355the instruction is a shorter version of the first that defaults to allocating
1356one element.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1357
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1358'<tt>type</tt>' may be any sized type.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1359
1360<h5>Semantics:</h5>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1361
1362Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d memory is
1363automatically released when the function returns. The '<tt>alloca</tt>'
1364instruction is commonly used to represent automatic variables that must have an
1365address available, as well as spilled variables.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1366
1367<h5>Example:</h5>
1368<pre>
1369 %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1370 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1371</pre>
1372
1373
1374<!-- _______________________________________________________________________ -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1375</ul><a name="i_load"><h4><hr size=0>'<tt>load</tt>' Instruction</h4><ul>
1376
1377<h5>Syntax:</h5>
1378<pre>
1379 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;
1380</pre>
1381
1382<h5>Overview:</h5>
1383The '<tt>load</tt>' instruction is used to read from memory.<p>
1384
1385<h5>Arguments:</h5>
1386
1387The 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.<p>
1388
1389<h5>Semantics:</h5>
1390
1391The location of memory pointed to is loaded.
1392
1393<h5>Examples:</h5>
1394<pre>
1395 %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1396 <a href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
1397 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1398</pre>
1399
1400
1401
1402
1403<!-- _______________________________________________________________________ -->
1404</ul><a name="i_store"><h4><hr size=0>'<tt>store</tt>' Instruction</h4><ul>
1405
1406<h5>Syntax:</h5>
1407<pre>
1408 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
1409</pre>
1410
1411<h5>Overview:</h5>
1412The '<tt>store</tt>' instruction is used to write to memory.<p>
1413
1414<h5>Arguments:</h5>
1415
1416There are two arguments to the '<tt>store</tt>' instruction: a value to store
1417and an address to store it into. The type of the '<tt>&lt;pointer&gt;</tt>'
1418operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
1419operand.<p>
1420
1421<h5>Semantics:</h5> The contents of memory are updated to contain
1422'<tt>&lt;value&gt;</tt>' at the location specified by the
1423'<tt>&lt;pointer&gt;</tt>' operand.<p>
1424
1425<h5>Example:</h5>
1426<pre>
1427 %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1428 <a href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
1429 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1430</pre>
1431
1432
1433
1434
1435<!-- _______________________________________________________________________ -->
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1436</ul><a name="i_getelementptr"><h4><hr size=0>'<tt>getelementptr</tt>' Instruction</h4><ul>
1437
1438<h5>Syntax:</h5>
1439<pre>
1440 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, uint &lt;aidx&gt;|, ubyte &lt;sidx&gt;}*
1441</pre>
1442
1443<h5>Overview:</h5>
1444
1445The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1446subelement of an aggregate data structure.<p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1447
1448<h5>Arguments:</h5>
1449
1450This instruction takes a list of <tt>uint</tt> values and <tt>ubyte</tt>
1451constants that indicate what form of addressing to perform. The actual types of
1452the arguments provided depend on the type of the first pointer argument. The
1453'<tt>getelementptr</tt>' instruction is used to index down through the type
1454levels of a structure.<p>
1455
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1456For example, lets consider a C code fragment and how it gets compiled to
1457LLVM:<p>
1458
1459<pre>
1460struct RT {
1461 char A;
1462 int B[10][20];
1463 char C;
1464};
1465struct ST {
1466 int X;
1467 double Y;
1468 struct RT Z;
1469};
1470
1471int *foo(struct ST *s) {
1472 return &amp;s[1].Z.B[5][13];
1473}
1474</pre>
1475
1476The LLVM code generated by the GCC frontend is:
1477
1478<pre>
1479%RT = type { sbyte, [10 x [20 x int]], sbyte }
1480%ST = type { int, double, %RT }
1481
1482int* "foo"(%ST* %s) {
1483 %reg = getelementptr %ST* %s, uint 1, ubyte 2, ubyte 1, uint 5, uint 13
1484 ret int* %reg
1485}
1486</pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1487
1488<h5>Semantics:</h5>
1489
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1490The index types specified for the '<tt>getelementptr</tt>' instruction depend on
1491the pointer type that is being index into. <a href="t_pointer">Pointer</a> and
1492<a href="t_array">array</a> types require '<tt>uint</tt>' values, and <a
1493href="t_struct">structure</a> types require '<tt>ubyte</tt>'
1494<b>constants</b>.<p>
1495
1496In the example above, the first index is indexing into the '<tt>%ST*</tt>' type,
1497which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT }</tt>'
1498type, a structure. The second index indexes into the third element of the
1499structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]], sbyte
1500}</tt>' type, another structure. The third index indexes into the second
1501element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
1502array. The two dimensions of the array are subscripted into, yielding an
1503'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer
1504to this element, thus yielding a '<tt>int*</tt>' type.<p>
1505
1506Note that it is perfectly legal to index partially through a structure,
1507returning a pointer to an inner element. Because of this, the LLVM code for the
1508given testcase is equivalent to:<p>
1509
1510<pre>
1511int* "foo"(%ST* %s) {
1512 %t1 = getelementptr %ST* %s , uint 1 <i>; yields %ST*:%t1</i>
1513 %t2 = getelementptr %ST* %t1, uint 0, ubyte 2 <i>; yields %RT*:%t2</i>
1514 %t3 = getelementptr %RT* %t2, uint 0, ubyte 1 <i>; yields [10 x [20 x int]]*:%t3</i>
1515 %t4 = getelementptr [10 x [20 x int]]* %t3, uint 0, uint 5 <i>; yields [20 x int]*:%t4</i>
1516 %t5 = getelementptr [20 x int]* %t4, uint 0, uint 13 <i>; yields int*:%t5</i>
1517 ret int* %t5
1518}
1519</pre>
1520
1521
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1522
1523<h5>Example:</h5>
1524<pre>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1525 <i>; yields {[12 x ubyte]*}:aptr</i>
1526 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, uint 0, ubyte 1
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1527</pre>
1528
1529
1530
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1531<!-- ======================================================================= -->
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1532</ul><table width="100%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
1533<tr><td>&nbsp;</td><td width="100%">&nbsp; <font color="#EEEEFF" face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1534<a name="otherops">Other Operations
1535</b></font></td></tr></table><ul>
1536
1537The instructions in this catagory are the "miscellaneous" functions, that defy better classification.<p>
1538
1539
1540<!-- _______________________________________________________________________ -->
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1541</ul><a name="i_phi"><h4><hr size=0>'<tt>phi</tt>' Instruction</h4><ul>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1542
1543<h5>Syntax:</h5>
1544<pre>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1545 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1546</pre>
1547
1548<h5>Overview:</h5>
1549
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1550The '<tt>phi</tt>' instruction is used to implement the &phi; node in the SSA
1551graph representing the function.<p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1552
1553<h5>Arguments:</h5>
1554
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1555The type of the incoming values are specified with the first type field. After
1556this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
1557one pair for each predecessor basic block of the current block.<p>
1558
1559There must be no non-phi instructions between the start of a basic block and the
1560PHI instructions: i.e. PHI instructions must be first in a basic block.<p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1561
1562<h5>Semantics:</h5>
1563
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1564At runtime, the '<tt>phi</tt>' instruction logically takes on the value
1565specified by the parameter, depending on which basic block we came from in the
1566last <a href="#terminators">terminator</a> instruction.<p>
1567
1568<h5>Example:</h5>
1569
1570<pre>
1571Loop: ; Infinite loop that counts from 0 on up...
1572 %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
1573 %nextindvar = add uint %indvar, 1
1574 br label %Loop
1575</pre>
1576
1577
1578<!-- _______________________________________________________________________ -->
1579</ul><a name="i_cast"><h4><hr size=0>'<tt>cast .. to</tt>' Instruction</h4><ul>
1580
1581<h5>Syntax:</h5>
1582<pre>
1583 &lt;result&gt; = cast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
1584</pre>
1585
1586<h5>Overview:</h5>
1587
1588The '<tt>cast</tt>' instruction is used as the primitive means to convert
1589integers to floating point, change data type sizes, and break type safety (by
1590casting pointers).<p>
1591
1592<h5>Arguments:</h5>
1593
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1594The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1595class value, and a type to cast it to, which must also be a first class type.<p>
1596
1597<h5>Semantics:</h5>
1598
1599This instruction follows the C rules for explicit casts when determining how the
1600data being cast must change to fit in its new container.<p>
1601
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1602When casting to bool, any value that would be considered true in the context of
1603a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
1604all else are '<tt>false</tt>'.<p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1605
1606<h5>Example:</h5>
1607<pre>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1608 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1609 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]1610</pre>
1611
1612
1613
1614<!-- _______________________________________________________________________ -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1615</ul><a name="i_call"><h4><hr size=0>'<tt>call</tt>' Instruction</h4><ul>
1616
1617<h5>Syntax:</h5>
1618<pre>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1619 &lt;result&gt; = call &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1620</pre>
1621
1622<h5>Overview:</h5>
1623
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1624The '<tt>call</tt>' instruction represents a simple function call.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1625
1626<h5>Arguments:</h5>
1627
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1628This instruction requires several arguments:<p>
1629<ol>
1630
1631<li>'<tt>ty</tt>': shall be the signature of the pointer to function value being
1632invoked. The argument types must match the types implied by this signature.<p>
1633
1634<li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to be
1635invoked. In most cases, this is a direct function invocation, but indirect
1636<tt>call</tt>'s are just as possible, calling an arbitrary pointer to function
1637values.<p>
1638
1639<li>'<tt>function args</tt>': argument list whose types match the function
1640signature argument types. If the function signature indicates the function
1641accepts a variable number of arguments, the extra arguments can be specified.
1642</ol>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1643
1644<h5>Semantics:</h5>
1645
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1646The '<tt>call</tt>' instruction is used to cause control flow to transfer to a
1647specified function, with its incoming arguments bound to the specified values.
1648Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called function,
1649control flow continues with the instruction after the function call, and the
1650return value of the function is bound to the result argument. This is a simpler
1651case of the <a href="#i_invoke">invoke</a> instruction.<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1652
1653<h5>Example:</h5>
1654<pre>
1655 %retval = call int %test(int %argc)
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1656 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
1657
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1658</pre>
1659
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1660<!--
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1661
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1662<!x- *********************************************************************** -x>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1663</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
1664<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1665<a name="related">Related Work
1666</b></font></td></tr></table><ul>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1667<!x- *********************************************************************** -x>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1668
1669
1670Codesigned virtual machines.<p>
1671
1672<dl>
1673<a name="rw_safetsa">
1674<dt>SafeTSA
1675<DD>Description here<p>
1676
1677<a name="rw_java">
1678<dt><a href="http://www.javasoft.com">Java</a>
1679<DD>Desciption here<p>
1680
1681<a name="rw_net">
1682<dt><a href="http://www.microsoft.com/net">Microsoft .net</a>
1683<DD>Desciption here<p>
1684
1685<a name="rw_gccrtl">
1686<dt><a href="http://www.math.umn.edu/systems_guide/gcc-2.95.1/gcc_15.html">GNU RTL Intermediate Representation</a>
1687<DD>Desciption here<p>
1688
1689<a name="rw_ia64">
1690<dt><a href="http://developer.intel.com/design/ia-64/index.htm">IA64 Architecture &amp; Instruction Set</a>
1691<DD>Desciption here<p>
1692
1693<a name="rw_mmix">
1694<dt><a href="http://www-cs-faculty.stanford.edu/~knuth/mmix-news.html">MMIX Instruction Set</a>
1695<DD>Desciption here<p>
1696
1697<a name="rw_stroustrup">
1698<dt><a href="http://www.research.att.com/~bs/devXinterview.html">"Interview With Bjarne Stroustrup"</a>
1699<DD>This interview influenced the design and thought process behind LLVM in several ways, most notably the way that derived types are written in text format. See the question that starts with "you defined the C declarator syntax as an experiment that failed".<p>
1700</dl>
1701
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1702<!x- _______________________________________________________________________ -x>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1703</ul><a name="rw_vectorization"><h3><hr size=0>Vectorized Architectures</h3><ul>
1704
1705<dl>
1706<a name="rw_intel_simd">
1707<dt>Intel MMX, MMX2, SSE, SSE2
1708<DD>Description here<p>
1709
1710<a name="rw_amd_simd">
1711<dt><a href="http://www.nondot.org/~sabre/os/H1ChipFeatures/3DNow!TechnologyManual.pdf">AMD 3Dnow!, 3Dnow! 2</a>
1712<DD>Desciption here<p>
1713
1714<a name="rw_sun_simd">
1715<dt><a href="http://www.nondot.org/~sabre/os/H1ChipFeatures/VISInstructionSetUsersManual.pdf">Sun VIS ISA</a>
1716<DD>Desciption here<p>
1717
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1718<a name="rw_powerpc_simd">
1719<dt>PowerPC Altivec
1720<DD>Desciption here<p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1721
1722</dl>
1723
1724more...
1725
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1726-->
1727
1728
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1729<!-- *********************************************************************** -->
1730</ul>
1731<!-- *********************************************************************** -->
1732
1733
1734<hr>
1735<font size=-1>
1736<address><a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
1737<!-- Created: Tue Jan 23 15:19:28 CST 2001 -->
1738<!-- hhmts start -->
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame^]1739Last modified: Tue Jun 25 12:54:52 CDT 2002
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1740<!-- hhmts end -->
1741</font>
1742</body></html>