Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / llvm / 72cba6cdf640411e2fb6207858a0abd87c4286fc / . / docs / TableGenFundamentals.html
blob: 58f9876d721742c3c01f356f3b0d52be3c5302cc [file] [log] [blame]
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
NAKAMURA Takumi5c6e4df2011-10-31 11:21:59 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]6 <title>TableGen Fundamentals</title>
Daniel Dunbaradea4972012-04-19 20:20:34 +0000[diff] [blame]7 <link rel="stylesheet" href="_static/llvm.css" type="text/css">
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]8</head>
9<body>
10
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]11<h1>TableGen Fundamentals</h1>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]12
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]13<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]14<ul>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]15 <li><a href="#introduction">Introduction</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]16 <ol>
17 <li><a href="#concepts">Basic concepts</a></li>
18 <li><a href="#example">An example record</a></li>
19 <li><a href="#running">Running TableGen</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]20 </ol></li>
21 <li><a href="#syntax">TableGen syntax</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]22 <ol>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]23 <li><a href="#primitives">TableGen primitives</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]24 <ol>
25 <li><a href="#comments">TableGen comments</a></li>
26 <li><a href="#types">The TableGen type system</a></li>
27 <li><a href="#values">TableGen values and expressions</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]28 </ol></li>
29 <li><a href="#classesdefs">Classes and definitions</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]30 <ol>
31 <li><a href="#valuedef">Value definitions</a></li>
32 <li><a href="#recordlet">'let' expressions</a></li>
33 <li><a href="#templateargs">Class template arguments</a></li>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]34 <li><a href="#multiclass">Multiclass definitions and instances</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]35 </ol></li>
36 <li><a href="#filescope">File scope entities</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]37 <ol>
38 <li><a href="#include">File inclusion</a></li>
39 <li><a href="#globallet">'let' expressions</a></li>
David Greenecebb4ee2012-02-22 16:09:41 +0000[diff] [blame]40 <li><a href="#foreach">'foreach' blocks</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]41 </ol></li>
42 </ol></li>
43 <li><a href="#backends">TableGen backends</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]44 <ol>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]45 <li><a href="#">todo</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]46 </ol></li>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]47</ul>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]48</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]49
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]50<div class="doc_author">
51 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p>
52</div>
53
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]54<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]55<h2><a name="introduction">Introduction</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]56<!-- *********************************************************************** -->
57
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]58<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]59
60<p>TableGen's purpose is to help a human develop and maintain records of
61domain-specific information. Because there may be a large number of these
62records, it is specifically designed to allow writing flexible descriptions and
63for common features of these records to be factored out. This reduces the
64amount of duplication in the description, reduces the chance of error, and
65makes it easier to structure domain specific information.</p>
66
67<p>The core part of TableGen <a href="#syntax">parses a file</a>, instantiates
68the declarations, and hands the result off to a domain-specific "<a
69href="#backends">TableGen backend</a>" for processing. The current major user
Chris Lattner1aab3272004-07-26 21:16:55 +0000[diff] [blame]70of TableGen is the <a href="CodeGenerator.html">LLVM code generator</a>.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]71
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]72<p>Note that if you work on TableGen much, and use emacs or vim, that you can
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]73find an emacs "TableGen mode" and a vim language file in the
74<tt>llvm/utils/emacs</tt> and <tt>llvm/utils/vim</tt> directories of your LLVM
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]75distribution, respectively.</p>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]76
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]77<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]78<h3><a name="concepts">Basic concepts</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]79
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]80<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]81
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]82<p>TableGen files consist of two key parts: 'classes' and 'definitions', both
83of which are considered 'records'.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]84
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]85<p><b>TableGen records</b> have a unique name, a list of values, and a list of
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]86superclasses. The list of values is the main data that TableGen builds for each
87record; it is this that holds the domain specific information for the
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]88application. The interpretation of this data is left to a specific <a
89href="#backends">TableGen backend</a>, but the structure and format rules are
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]90taken care of and are fixed by TableGen.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]91
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]92<p><b>TableGen definitions</b> are the concrete form of 'records'. These
93generally do not have any undefined values, and are marked with the
94'<tt>def</tt>' keyword.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]95
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]96<p><b>TableGen classes</b> are abstract records that are used to build and
97describe other records. These 'classes' allow the end-user to build
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]98abstractions for either the domain they are targeting (such as "Register",
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]99"RegisterClass", and "Instruction" in the LLVM code generator) or for the
100implementor to help factor out common properties of records (such as "FPInst",
101which is used to represent floating point instructions in the X86 backend).
102TableGen keeps track of all of the classes that are used to build up a
103definition, so the backend can find all definitions of a particular class, such
104as "Instruction".</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]105
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]106<p><b>TableGen multiclasses</b> are groups of abstract records that are
David Greenede444af2009-04-22 16:42:54 +0000[diff] [blame]107instantiated all at once. Each instantiation can result in multiple
108TableGen definitions. If a multiclass inherits from another multiclass,
109the definitions in the sub-multiclass become part of the current
110multiclass, as if they were declared in the current multiclass.</p>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]111
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]112</div>
113
114<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]115<h3><a name="example">An example record</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]116
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]117<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]118
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]119<p>With no other arguments, TableGen parses the specified file and prints out
120all of the classes, then all of the definitions. This is a good way to see what
121the various definitions expand to fully. Running this on the <tt>X86.td</tt>
122file prints this (at the time of this writing):</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]123
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]124<div class="doc_code">
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]125<pre>
126...
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]127<b>def</b> ADD32rr { <i>// Instruction X86Inst I</i>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]128 <b>string</b> Namespace = "X86";
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]129 <b>dag</b> OutOperandList = (outs GR32:$dst);
130 <b>dag</b> InOperandList = (ins GR32:$src1, GR32:$src2);
131 <b>string</b> AsmString = "add{l}\t{$src2, $dst|$dst, $src2}";
132 <b>list</b>&lt;dag&gt; Pattern = [(set GR32:$dst, (add GR32:$src1, GR32:$src2))];
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]133 <b>list</b>&lt;Register&gt; Uses = [];
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]134 <b>list</b>&lt;Register&gt; Defs = [EFLAGS];
135 <b>list</b>&lt;Predicate&gt; Predicates = [];
136 <b>int</b> CodeSize = 3;
137 <b>int</b> AddedComplexity = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]138 <b>bit</b> isReturn = 0;
139 <b>bit</b> isBranch = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]140 <b>bit</b> isIndirectBranch = 0;
141 <b>bit</b> isBarrier = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]142 <b>bit</b> isCall = 0;
Dan Gohman15511cf2008-12-03 18:15:48 +0000[diff] [blame]143 <b>bit</b> canFoldAsLoad = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]144 <b>bit</b> mayLoad = 0;
145 <b>bit</b> mayStore = 0;
146 <b>bit</b> isImplicitDef = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]147 <b>bit</b> isConvertibleToThreeAddress = 1;
148 <b>bit</b> isCommutable = 1;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]149 <b>bit</b> isTerminator = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]150 <b>bit</b> isReMaterializable = 0;
151 <b>bit</b> isPredicable = 0;
152 <b>bit</b> hasDelaySlot = 0;
Dan Gohman533297b2009-10-29 18:10:34 +0000[diff] [blame]153 <b>bit</b> usesCustomInserter = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]154 <b>bit</b> hasCtrlDep = 0;
155 <b>bit</b> isNotDuplicable = 0;
156 <b>bit</b> hasSideEffects = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]157 <b>bit</b> neverHasSideEffects = 0;
158 InstrItinClass Itinerary = NoItinerary;
159 <b>string</b> Constraints = "";
160 <b>string</b> DisableEncoding = "";
161 <b>bits</b>&lt;8&gt; Opcode = { 0, 0, 0, 0, 0, 0, 0, 1 };
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]162 Format Form = MRMDestReg;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]163 <b>bits</b>&lt;6&gt; FormBits = { 0, 0, 0, 0, 1, 1 };
164 ImmType ImmT = NoImm;
165 <b>bits</b>&lt;3&gt; ImmTypeBits = { 0, 0, 0 };
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]166 <b>bit</b> hasOpSizePrefix = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]167 <b>bit</b> hasAdSizePrefix = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]168 <b>bits</b>&lt;4&gt; Prefix = { 0, 0, 0, 0 };
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]169 <b>bit</b> hasREX_WPrefix = 0;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]170 FPFormat FPForm = ?;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]171 <b>bits</b>&lt;3&gt; FPFormBits = { 0, 0, 0 };
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]172}
173...
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]174</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]175</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]176
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]177<p>This definition corresponds to a 32-bit register-register add instruction in
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]178the X86. The string after the '<tt>def</tt>' string indicates the name of the
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]179record&mdash;"<tt>ADD32rr</tt>" in this case&mdash;and the comment at the end of
180the line indicates the superclasses of the definition. The body of the record
181contains all of the data that TableGen assembled for the record, indicating that
182the instruction is part of the "X86" namespace, the pattern indicating how the
183the instruction should be emitted into the assembly file, that it is a
184two-address instruction, has a particular encoding, etc. The contents and
185semantics of the information in the record is specific to the needs of the X86
186backend, and is only shown as an example.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]187
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]188<p>As you can see, a lot of information is needed for every instruction
189supported by the code generator, and specifying it all manually would be
Dan Gohman8ff4b432010-02-26 02:15:17 +0000[diff] [blame]190unmaintainable, prone to bugs, and tiring to do in the first place. Because we
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]191are using TableGen, all of the information was derived from the following
192definition:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]193
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]194<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]195<pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]196let Defs = [EFLAGS],
197 isCommutable = 1, <i>// X = ADD Y,Z --&gt; X = ADD Z,Y</i>
198 isConvertibleToThreeAddress = 1 <b>in</b> <i>// Can transform into LEA.</i>
199def ADD32rr : I&lt;0x01, MRMDestReg, (outs GR32:$dst),
200 (ins GR32:$src1, GR32:$src2),
201 "add{l}\t{$src2, $dst|$dst, $src2}",
202 [(set GR32:$dst, (add GR32:$src1, GR32:$src2))]&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]203</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]204</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]205
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]206<p>This definition makes use of the custom class <tt>I</tt> (extended from the
207custom class <tt>X86Inst</tt>), which is defined in the X86-specific TableGen
208file, to factor out the common features that instructions of its class share. A
209key feature of TableGen is that it allows the end-user to define the
210abstractions they prefer to use when describing their information.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]211
David Greenedc5287c2011-10-19 13:04:56 +0000[diff] [blame]212<p>Each def record has a special entry called "NAME." This is the
213name of the def ("ADD32rr" above). In the general case def names can
214be formed from various kinds of string processing expressions and NAME
215resolves to the final value obtained after resolving all of those
216expressions. The user may refer to NAME anywhere she desires to use
217the ultimate name of the def. NAME should not be defined anywhere
218else in user code to avoid conflict problems.</p>
219
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]220</div>
221
222<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]223<h3><a name="running">Running TableGen</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]224
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]225<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]226
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]227<p>TableGen runs just like any other LLVM tool. The first (optional) argument
Joel Jones175e6f72012-05-24 04:38:50 +0000[diff] [blame]228specifies the file to read. If a filename is not specified,
229<tt>llvm-tblgen</tt> reads from standard input.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]230
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]231<p>To be useful, one of the <a href="#backends">TableGen backends</a> must be
Joel Jones175e6f72012-05-24 04:38:50 +0000[diff] [blame]232used. These backends are selectable on the command line (type '<tt>llvm-tblgen
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]233-help</tt>' for a list). For example, to get a list of all of the definitions
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]234that subclass a particular type (which can be useful for building up an enum
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]235list of these records), use the <tt>-print-enums</tt> option:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]236
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]237<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]238<pre>
Joel Jones175e6f72012-05-24 04:38:50 +0000[diff] [blame]239$ llvm-tblgen X86.td -print-enums -class=Register
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]240AH, AL, AX, BH, BL, BP, BPL, BX, CH, CL, CX, DH, DI, DIL, DL, DX, EAX, EBP, EBX,
241ECX, EDI, EDX, EFLAGS, EIP, ESI, ESP, FP0, FP1, FP2, FP3, FP4, FP5, FP6, IP,
242MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7, R10, R10B, R10D, R10W, R11, R11B, R11D,
243R11W, R12, R12B, R12D, R12W, R13, R13B, R13D, R13W, R14, R14B, R14D, R14W, R15,
244R15B, R15D, R15W, R8, R8B, R8D, R8W, R9, R9B, R9D, R9W, RAX, RBP, RBX, RCX, RDI,
245RDX, RIP, RSI, RSP, SI, SIL, SP, SPL, ST0, ST1, ST2, ST3, ST4, ST5, ST6, ST7,
246XMM0, XMM1, XMM10, XMM11, XMM12, XMM13, XMM14, XMM15, XMM2, XMM3, XMM4, XMM5,
247XMM6, XMM7, XMM8, XMM9,
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]248
Joel Jones175e6f72012-05-24 04:38:50 +0000[diff] [blame]249$ llvm-tblgen X86.td -print-enums -class=Instruction
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]250ABS_F, ABS_Fp32, ABS_Fp64, ABS_Fp80, ADC32mi, ADC32mi8, ADC32mr, ADC32ri,
251ADC32ri8, ADC32rm, ADC32rr, ADC64mi32, ADC64mi8, ADC64mr, ADC64ri32, ADC64ri8,
252ADC64rm, ADC64rr, ADD16mi, ADD16mi8, ADD16mr, ADD16ri, ADD16ri8, ADD16rm,
253ADD16rr, ADD32mi, ADD32mi8, ADD32mr, ADD32ri, ADD32ri8, ADD32rm, ADD32rr,
254ADD64mi32, ADD64mi8, ADD64mr, ADD64ri32, ...
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]255</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]256</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]257
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]258<p>The default backend prints out all of the records, as described <a
259href="#example">above</a>.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]260
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]261<p>If you plan to use TableGen, you will most likely have to <a
262href="#backends">write a backend</a> that extracts the information specific to
263what you need and formats it in the appropriate way.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]264
265</div>
266
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]267</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]268
269<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]270<h2><a name="syntax">TableGen syntax</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]271<!-- *********************************************************************** -->
272
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]273<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]274
275<p>TableGen doesn't care about the meaning of data (that is up to the backend to
276define), but it does care about syntax, and it enforces a simple type system.
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]277This section describes the syntax and the constructs allowed in a TableGen file.
278</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]279
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]280<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]281<h3><a name="primitives">TableGen primitives</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]282
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]283<div>
284
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]285<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]286<h4><a name="comments">TableGen comments</a></h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]287
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]288<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]289
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]290<p>TableGen supports BCPL style "<tt>//</tt>" comments, which run to the end of
291the line, and it also supports <b>nestable</b> "<tt>/* */</tt>" comments.</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]292
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]293</div>
294
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]295<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]296<h4>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]297 <a name="types">The TableGen type system</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]298</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]299
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]300<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]301
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]302<p>TableGen files are strongly typed, in a simple (but complete) type-system.
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]303These types are used to perform automatic conversions, check for errors, and to
304help interface designers constrain the input that they allow. Every <a
305href="#valuedef">value definition</a> is required to have an associated type.
306</p>
307
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]308<p>TableGen supports a mixture of very low-level types (such as <tt>bit</tt>)
309and very high-level types (such as <tt>dag</tt>). This flexibility is what
310allows it to describe a wide range of information conveniently and compactly.
311The TableGen types are:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]312
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]313<dl>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]314<dt><tt><b>bit</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]315 <dd>A 'bit' is a boolean value that can hold either 0 or 1.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]316
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]317<dt><tt><b>int</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]318 <dd>The 'int' type represents a simple 32-bit integer value, such as 5.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]319
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]320<dt><tt><b>string</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]321 <dd>The 'string' type represents an ordered sequence of characters of
322 arbitrary length.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]323
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]324<dt><tt><b>bits</b>&lt;n&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]325 <dd>A 'bits' type is an arbitrary, but fixed, size integer that is broken up
326 into individual bits. This type is useful because it can handle some bits
327 being defined while others are undefined.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]328
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]329<dt><tt><b>list</b>&lt;ty&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]330 <dd>This type represents a list whose elements are some other type. The
331 contained type is arbitrary: it can even be another list type.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]332
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]333<dt>Class type</dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]334 <dd>Specifying a class name in a type context means that the defined value
335 must be a subclass of the specified class. This is useful in conjunction with
336 the <b><tt>list</tt></b> type, for example, to constrain the elements of the
337 list to a common base class (e.g., a <tt><b>list</b>&lt;Register&gt;</tt> can
338 only contain definitions derived from the "<tt>Register</tt>" class).</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]339
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]340<dt><tt><b>dag</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]341 <dd>This type represents a nestable directed graph of elements.</dd>
342
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]343<dt><tt><b>code</b></tt></dt>
Chris Lattnerca73cea2010-04-22 16:45:27 +0000[diff] [blame]344 <dd>This represents a big hunk of text. This is lexically distinct from
345 string values because it doesn't require escapeing double quotes and other
346 common characters that occur in code.</dd>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]347</dl>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]348
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]349<p>To date, these types have been sufficient for describing things that
350TableGen has been used for, but it is straight-forward to extend this list if
351needed.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]352
353</div>
354
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]355<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]356<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]357 <a name="values">TableGen values and expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]358</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]359
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]360<div>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]361
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]362<p>TableGen allows for a pretty reasonable number of different expression forms
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]363when building up values. These forms allow the TableGen file to be written in a
364natural syntax and flavor for the application. The current expression forms
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]365supported include:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]366
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]367<dl>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]368<dt><tt>?</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]369 <dd>uninitialized field</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]370<dt><tt>0b1001011</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]371 <dd>binary integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]372<dt><tt>07654321</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]373 <dd>octal integer value (indicated by a leading 0)</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]374<dt><tt>7</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]375 <dd>decimal integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]376<dt><tt>0x7F</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]377 <dd>hexadecimal integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]378<dt><tt>"foo"</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]379 <dd>string value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]380<dt><tt>[{ ... }]</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]381 <dd>code fragment</dd>
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]382<dt><tt>[ X, Y, Z ]&lt;type&gt;</tt></dt>
383 <dd>list value. &lt;type&gt; is the type of the list
David Greeneccbfb8d2009-06-08 22:38:07 +0000[diff] [blame]384element and is usually optional. In rare cases,
385TableGen is unable to deduce the element type in
386which case the user must specify it explicitly.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]387<dt><tt>{ a, b, c }</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]388 <dd>initializer for a "bits&lt;3&gt;" value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]389<dt><tt>value</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]390 <dd>value reference</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]391<dt><tt>value{17}</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]392 <dd>access to one bit of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]393<dt><tt>value{15-17}</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]394 <dd>access to multiple bits of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]395<dt><tt>DEF</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]396 <dd>reference to a record definition</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]397<dt><tt>CLASS&lt;val list&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]398 <dd>reference to a new anonymous definition of CLASS with the specified
399 template arguments.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]400<dt><tt>X.Y</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]401 <dd>reference to the subfield of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]402<dt><tt>list[4-7,17,2-3]</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]403 <dd>A slice of the 'list' list, including elements 4,5,6,7,17,2, and 3 from
404 it. Elements may be included multiple times.</dd>
David Greenecebb4ee2012-02-22 16:09:41 +0000[diff] [blame]405<dt><tt>foreach &lt;var&gt; = &lt;list&gt; in { &lt;body&gt; }</tt></dt>
406<dt><tt>foreach &lt;var&gt; = &lt;list&gt; in &lt;def&gt;</tt></dt>
407 <dd> Replicate &lt;body&gt; or &lt;def&gt;, replacing instances of
408 &lt;var&gt; with each value in &lt;list&gt;. &lt;var&gt; is scoped at the
409 level of the <tt>foreach</tt> loop and must not conflict with any other object
410 introduced in &lt;body&gt; or &lt;def&gt;. Currently only <tt>def</tt>s are
411 expanded within &lt;body&gt;.
412 </dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]413<dt><tt>(DEF a, b)</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]414 <dd>a dag value. The first element is required to be a record definition, the
415 remaining elements in the list may be arbitrary other values, including nested
416 `<tt>dag</tt>' values.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]417<dt><tt>!strconcat(a, b)</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]418 <dd>A string value that is the result of concatenating the 'a' and 'b'
419 strings.</dd>
David Greene40230c42011-10-19 13:04:59 +0000[diff] [blame]420<dt><tt>str1#str2</tt></dt>
421 <dd>"#" (paste) is a shorthand for !strconcat. It may concatenate
422 things that are not quoted strings, in which case an implicit
NAKAMURA Takumi9c55f592012-03-27 11:25:16 +0000[diff] [blame]423 !cast&lt;string&gt; is done on the operand of the paste.</dd>
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]424<dt><tt>!cast&lt;type&gt;(a)</tt></dt>
David Greenee6c27de2009-05-14 21:22:49 +0000[diff] [blame]425 <dd>A symbol of type <em>type</em> obtained by looking up the string 'a' in
426the symbol table. If the type of 'a' does not match <em>type</em>, TableGen
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]427aborts with an error. !cast&lt;string&gt; is a special case in that the argument must
David Greene2c026622009-06-29 20:05:29 +0000[diff] [blame]428be an object defined by a 'def' construct.</dd>
David Greene4afc5092009-05-14 21:54:42 +0000[diff] [blame]429<dt><tt>!subst(a, b, c)</tt></dt>
430 <dd>If 'a' and 'b' are of string type or are symbol references, substitute
431'b' for 'a' in 'c.' This operation is analogous to $(subst) in GNU make.</dd>
David Greenebeb31a52009-05-14 22:23:47 +0000[diff] [blame]432<dt><tt>!foreach(a, b, c)</tt></dt>
433 <dd>For each member 'b' of dag or list 'a' apply operator 'c.' 'b' is a
434dummy variable that should be declared as a member variable of an instantiated
435class. This operation is analogous to $(foreach) in GNU make.</dd>
David Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]436<dt><tt>!head(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]437 <dd>The first element of list 'a.'</dd>
David Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]438<dt><tt>!tail(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]439 <dd>The 2nd-N elements of list 'a.'</dd>
David Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]440<dt><tt>!empty(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]441 <dd>An integer {0,1} indicating whether list 'a' is empty.</dd>
David Greene9bea7c82009-05-14 23:26:46 +0000[diff] [blame]442<dt><tt>!if(a,b,c)</tt></dt>
Bruno Cardoso Lopeseba8f182010-06-17 00:31:36 +0000[diff] [blame]443 <dd>'b' if the result of 'int' or 'bit' operator 'a' is nonzero,
444 'c' otherwise.</dd>
David Greene6786d5e2010-01-05 19:11:42 +0000[diff] [blame]445<dt><tt>!eq(a,b)</tt></dt>
Chris Lattner150d20e2010-10-31 19:22:57 +0000[diff] [blame]446 <dd>'bit 1' if string a is equal to string b, 0 otherwise. This
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]447 only operates on string, int and bit objects. Use !cast&lt;string&gt; to
Bruno Cardoso Lopese87de412010-06-16 23:24:12 +0000[diff] [blame]448 compare other types of objects.</dd>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]449</dl>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]450
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]451<p>Note that all of the values have rules specifying how they convert to values
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]452for different types. These rules allow you to assign a value like "<tt>7</tt>"
453to a "<tt>bits&lt;4&gt;</tt>" value, for example.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]454
455</div>
456
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]457</div>
458
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]459<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]460<h3>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]461 <a name="classesdefs">Classes and definitions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]462</h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]463
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]464<div>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]465
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]466<p>As mentioned in the <a href="#concepts">intro</a>, classes and definitions
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]467(collectively known as 'records') in TableGen are the main high-level unit of
468information that TableGen collects. Records are defined with a <tt>def</tt> or
469<tt>class</tt> keyword, the record name, and an optional list of "<a
Misha Brukman179bf4b2004-06-03 23:42:24 +0000[diff] [blame]470href="#templateargs">template arguments</a>". If the record has superclasses,
Jeff Cohen0b81cda2005-10-24 16:54:55 +0000[diff] [blame]471they are specified as a comma separated list that starts with a colon character
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]472("<tt>:</tt>"). If <a href="#valuedef">value definitions</a> or <a
473href="#recordlet">let expressions</a> are needed for the class, they are
474enclosed in curly braces ("<tt>{}</tt>"); otherwise, the record ends with a
475semicolon.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]476
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]477<p>Here is a simple TableGen file:</p>
478
479<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]480<pre>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]481<b>class</b> C { <b>bit</b> V = 1; }
482<b>def</b> X : C;
483<b>def</b> Y : C {
484 <b>string</b> Greeting = "hello";
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]485}
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]486</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]487</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]488
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]489<p>This example defines two definitions, <tt>X</tt> and <tt>Y</tt>, both of
490which derive from the <tt>C</tt> class. Because of this, they both get the
491<tt>V</tt> bit value. The <tt>Y</tt> definition also gets the Greeting member
492as well.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]493
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]494<p>In general, classes are useful for collecting together the commonality
495between a group of records and isolating it in a single place. Also, classes
496permit the specification of default values for their subclasses, allowing the
497subclasses to override them as they wish.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]498
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]499<!---------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]500<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]501 <a name="valuedef">Value definitions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]502</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]503
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]504<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]505
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]506<p>Value definitions define named entries in records. A value must be defined
John Criswellaa55c8c2004-02-12 18:11:53 +0000[diff] [blame]507before it can be referred to as the operand for another value definition or
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]508before the value is reset with a <a href="#recordlet">let expression</a>. A
509value is defined by specifying a <a href="#types">TableGen type</a> and a name.
510If an initial value is available, it may be specified after the type with an
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]511equal sign. Value definitions require terminating semicolons.</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]512
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]513</div>
514
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]515<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]516<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]517 <a name="recordlet">'let' expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]518</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]519
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]520<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]521
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]522<p>A record-level let expression is used to change the value of a value
523definition in a record. This is primarily useful when a superclass defines a
524value that a derived class or definition wants to override. Let expressions
525consist of the '<tt>let</tt>' keyword followed by a value name, an equal sign
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]526("<tt>=</tt>"), and a new value. For example, a new class could be added to the
527example above, redefining the <tt>V</tt> field for all of its subclasses:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]528
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]529<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]530<pre>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]531<b>class</b> D : C { let V = 0; }
532<b>def</b> Z : D;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]533</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]534</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]535
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]536<p>In this case, the <tt>Z</tt> definition will have a zero value for its "V"
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]537value, despite the fact that it derives (indirectly) from the <tt>C</tt> class,
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]538because the <tt>D</tt> class overrode its value.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]539
540</div>
541
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]542<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]543<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]544 <a name="templateargs">Class template arguments</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]545</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]546
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]547<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]548
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]549<p>TableGen permits the definition of parameterized classes as well as normal
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]550concrete classes. Parameterized TableGen classes specify a list of variable
551bindings (which may optionally have defaults) that are bound when used. Here is
552a simple example:</p>
553
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]554<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]555<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]556<b>class</b> FPFormat&lt;<b>bits</b>&lt;3&gt; val&gt; {
557 <b>bits</b>&lt;3&gt; Value = val;
558}
559<b>def</b> NotFP : FPFormat&lt;0&gt;;
560<b>def</b> ZeroArgFP : FPFormat&lt;1&gt;;
561<b>def</b> OneArgFP : FPFormat&lt;2&gt;;
562<b>def</b> OneArgFPRW : FPFormat&lt;3&gt;;
563<b>def</b> TwoArgFP : FPFormat&lt;4&gt;;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]564<b>def</b> CompareFP : FPFormat&lt;5&gt;;
565<b>def</b> CondMovFP : FPFormat&lt;6&gt;;
566<b>def</b> SpecialFP : FPFormat&lt;7&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]567</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]568</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]569
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]570<p>In this case, template arguments are used as a space efficient way to specify
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]571a list of "enumeration values", each with a "<tt>Value</tt>" field set to the
572specified integer.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]573
574<p>The more esoteric forms of <a href="#values">TableGen expressions</a> are
575useful in conjunction with template arguments. As an example:</p>
576
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]577<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]578<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]579<b>class</b> ModRefVal&lt;<b>bits</b>&lt;2&gt; val&gt; {
580 <b>bits</b>&lt;2&gt; Value = val;
581}
582
583<b>def</b> None : ModRefVal&lt;0&gt;;
584<b>def</b> Mod : ModRefVal&lt;1&gt;;
585<b>def</b> Ref : ModRefVal&lt;2&gt;;
586<b>def</b> ModRef : ModRefVal&lt;3&gt;;
587
588<b>class</b> Value&lt;ModRefVal MR&gt; {
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]589 <i>// Decode some information into a more convenient format, while providing
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]590 // a nice interface to the user of the "Value" class.</i>
591 <b>bit</b> isMod = MR.Value{0};
592 <b>bit</b> isRef = MR.Value{1};
593
594 <i>// other stuff...</i>
595}
596
597<i>// Example uses</i>
598<b>def</b> bork : Value&lt;Mod&gt;;
599<b>def</b> zork : Value&lt;Ref&gt;;
600<b>def</b> hork : Value&lt;ModRef&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]601</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]602</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]603
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]604<p>This is obviously a contrived example, but it shows how template arguments
605can be used to decouple the interface provided to the user of the class from the
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]606actual internal data representation expected by the class. In this case,
Joel Jones175e6f72012-05-24 04:38:50 +0000[diff] [blame]607running <tt>llvm-tblgen</tt> on the example prints the following
608definitions:</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]609
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]610<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]611<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]612<b>def</b> bork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]613 <b>bit</b> isMod = 1;
614 <b>bit</b> isRef = 0;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]615}
616<b>def</b> hork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]617 <b>bit</b> isMod = 1;
618 <b>bit</b> isRef = 1;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]619}
620<b>def</b> zork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]621 <b>bit</b> isMod = 0;
622 <b>bit</b> isRef = 1;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]623}
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]624</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]625</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]626
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]627<p> This shows that TableGen was able to dig into the argument and extract a
628piece of information that was requested by the designer of the "Value" class.
629For more realistic examples, please see existing users of TableGen, such as the
630X86 backend.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]631
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]632</div>
633
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]634<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]635<h4>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]636 <a name="multiclass">Multiclass definitions and instances</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]637</h4>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]638
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]639<div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]640
641<p>
642While classes with template arguments are a good way to factor commonality
643between two instances of a definition, multiclasses allow a convenient notation
644for defining multiple definitions at once (instances of implicitly constructed
645classes). For example, consider an 3-address instruction set whose instructions
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]646come in two forms: "<tt>reg = reg op reg</tt>" and "<tt>reg = reg op imm</tt>"
647(e.g. SPARC). In this case, you'd like to specify in one place that this
648commonality exists, then in a separate place indicate what all the ops are.
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]649</p>
650
651<p>
652Here is an example TableGen fragment that shows this idea:
653</p>
654
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]655<div class="doc_code">
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]656<pre>
657<b>def</b> ops;
658<b>def</b> GPR;
659<b>def</b> Imm;
660<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
661
662<b>multiclass</b> ri_inst&lt;<b>int</b> opc, <b>string</b> asmstr&gt; {
663 def _rr : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
664 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
665 def _ri : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
666 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
667}
668
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]669<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]670<b>defm</b> ADD : ri_inst&lt;0b111, "add"&gt;;
671<b>defm</b> SUB : ri_inst&lt;0b101, "sub"&gt;;
672<b>defm</b> MUL : ri_inst&lt;0b100, "mul"&gt;;
673...
674</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]675</div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]676
Chris Lattnere7173e12006-09-01 22:01:36 +0000[diff] [blame]677<p>The name of the resultant definitions has the multidef fragment names
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]678 appended to them, so this defines <tt>ADD_rr</tt>, <tt>ADD_ri</tt>,
David Greene56546132009-04-22 22:17:51 +0000[diff] [blame]679 <tt>SUB_rr</tt>, etc. A defm may inherit from multiple multiclasses,
680 instantiating definitions from each multiclass. Using a multiclass
681 this way is exactly equivalent to instantiating the classes multiple
682 times yourself, e.g. by writing:</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]683
684<div class="doc_code">
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]685<pre>
686<b>def</b> ops;
687<b>def</b> GPR;
688<b>def</b> Imm;
689<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
690
691<b>class</b> rrinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
692 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
693 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
694
695<b>class</b> riinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
696 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
697 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
698
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]699<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]700<b>def</b> ADD_rr : rrinst&lt;0b111, "add"&gt;;
701<b>def</b> ADD_ri : riinst&lt;0b111, "add"&gt;;
702<b>def</b> SUB_rr : rrinst&lt;0b101, "sub"&gt;;
703<b>def</b> SUB_ri : riinst&lt;0b101, "sub"&gt;;
704<b>def</b> MUL_rr : rrinst&lt;0b100, "mul"&gt;;
705<b>def</b> MUL_ri : riinst&lt;0b100, "mul"&gt;;
706...
707</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]708</div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]709
Bruno Cardoso Lopes270562b2010-06-05 02:11:52 +0000[diff] [blame]710<p>
711A defm can also be used inside a multiclass providing several levels of
712multiclass instanciations.
713</p>
714
715<div class="doc_code">
716<pre>
717<b>class</b> Instruction&lt;bits&lt;4&gt; opc, string Name&gt; {
718 bits&lt;4&gt; opcode = opc;
719 string name = Name;
720}
721
722<b>multiclass</b> basic_r&lt;bits&lt;4&gt; opc&gt; {
723 <b>def</b> rr : Instruction&lt;opc, "rr"&gt;;
724 <b>def</b> rm : Instruction&lt;opc, "rm"&gt;;
725}
726
727<b>multiclass</b> basic_s&lt;bits&lt;4&gt; opc&gt; {
728 <b>defm</b> SS : basic_r&lt;opc&gt;;
729 <b>defm</b> SD : basic_r&lt;opc&gt;;
730 <b>def</b> X : Instruction&lt;opc, "x"&gt;;
731}
732
733<b>multiclass</b> basic_p&lt;bits&lt;4&gt; opc&gt; {
734 <b>defm</b> PS : basic_r&lt;opc&gt;;
735 <b>defm</b> PD : basic_r&lt;opc&gt;;
736 <b>def</b> Y : Instruction&lt;opc, "y"&gt;;
737}
738
739<b>defm</b> ADD : basic_s&lt;0xf&gt;, basic_p&lt;0xf&gt;;
740...
741
742<i>// Results</i>
743<b>def</b> ADDPDrm { ...
744<b>def</b> ADDPDrr { ...
745<b>def</b> ADDPSrm { ...
746<b>def</b> ADDPSrr { ...
747<b>def</b> ADDSDrm { ...
748<b>def</b> ADDSDrr { ...
749<b>def</b> ADDY { ...
750<b>def</b> ADDX { ...
751</pre>
752</div>
753
Bruno Cardoso Lopes6e0a99a2010-06-18 19:53:41 +0000[diff] [blame]754<p>
755defm declarations can inherit from classes too, the
756rule to follow is that the class list must start after the
757last multiclass, and there must be at least one multiclass
758before them.
759</p>
760
761<div class="doc_code">
762<pre>
763<b>class</b> XD { bits&lt;4&gt; Prefix = 11; }
764<b>class</b> XS { bits&lt;4&gt; Prefix = 12; }
765
766<b>class</b> I&lt;bits<4&gt; op> {
767 bits&lt;4&gt; opcode = op;
768}
769
770<b>multiclass</b> R {
771 <b>def</b> rr : I&lt;4&gt;;
772 <b>def</b> rm : I&lt;2&gt;;
773}
774
775<b>multiclass</b> Y {
776 <b>defm</b> SS : R, XD;
777 <b>defm</b> SD : R, XS;
778}
779
780<b>defm</b> Instr : Y;
781
782<i>// Results</i>
783<b>def</b> InstrSDrm {
784 bits&lt;4&gt; opcode = { 0, 0, 1, 0 };
785 bits&lt;4&gt; Prefix = { 1, 1, 0, 0 };
786}
787...
788<b>def</b> InstrSSrr {
789 bits&lt;4&gt; opcode = { 0, 1, 0, 0 };
790 bits&lt;4&gt; Prefix = { 1, 0, 1, 1 };
791}
792</pre>
793</div>
794
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]795</div>
796
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]797</div>
798
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]799<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]800<h3>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]801 <a name="filescope">File scope entities</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]802</h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]803
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]804<div>
805
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]806<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]807<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]808 <a name="include">File inclusion</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]809</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]810
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]811<div>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]812<p>TableGen supports the '<tt>include</tt>' token, which textually substitutes
813the specified file in place of the include directive. The filename should be
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]814specified as a double quoted string immediately after the '<tt>include</tt>'
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]815keyword. Example:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]816
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]817<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]818<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]819<b>include</b> "foo.td"
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]820</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]821</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]822
823</div>
824
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]825<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]826<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]827 <a name="globallet">'let' expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]828</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]829
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]830<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]831
832<p>"Let" expressions at file scope are similar to <a href="#recordlet">"let"
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]833expressions within a record</a>, except they can specify a value binding for
834multiple records at a time, and may be useful in certain other cases.
835File-scope let expressions are really just another way that TableGen allows the
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]836end-user to factor out commonality from the records.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]837
Jeff Cohen0b81cda2005-10-24 16:54:55 +0000[diff] [blame]838<p>File-scope "let" expressions take a comma-separated list of bindings to
Matthijs Kooijman94199da2008-10-20 08:45:34 +0000[diff] [blame]839apply, and one or more records to bind the values in. Here are some
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]840examples:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]841
Bill Wendling6171ab62010-12-08 02:46:25 +0000[diff] [blame]842<div class="doc_code">
843<pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]844<b>let</b> isTerminator = 1, isReturn = 1, isBarrier = 1, hasCtrlDep = 1 <b>in</b>
845 <b>def</b> RET : I&lt;0xC3, RawFrm, (outs), (ins), "ret", [(X86retflag 0)]&gt;;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]846
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]847<b>let</b> isCall = 1 <b>in</b>
848 <i>// All calls clobber the non-callee saved registers...</i>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]849 <b>let</b> Defs = [EAX, ECX, EDX, FP0, FP1, FP2, FP3, FP4, FP5, FP6, ST0,
850 MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7,
851 XMM0, XMM1, XMM2, XMM3, XMM4, XMM5, XMM6, XMM7, EFLAGS] <b>in</b> {
Dan Gohman364a39f2008-10-14 17:00:38 +0000[diff] [blame]852 <b>def</b> CALLpcrel32 : Ii32&lt;0xE8, RawFrm, (outs), (ins i32imm:$dst,variable_ops),
853 "call\t${dst:call}", []&gt;;
854 <b>def</b> CALL32r : I&lt;0xFF, MRM2r, (outs), (ins GR32:$dst, variable_ops),
855 "call\t{*}$dst", [(X86call GR32:$dst)]&gt;;
856 <b>def</b> CALL32m : I&lt;0xFF, MRM2m, (outs), (ins i32mem:$dst, variable_ops),
857 "call\t{*}$dst", []&gt;;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]858 }
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]859</pre>
Bill Wendling6171ab62010-12-08 02:46:25 +0000[diff] [blame]860</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]861
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]862<p>File-scope "let" expressions are often useful when a couple of definitions
863need to be added to several records, and the records do not otherwise need to be
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]864opened, as in the case with the <tt>CALL*</tt> instructions above.</p>
865
Bruno Cardoso Lopesee65db32010-06-10 02:42:59 +0000[diff] [blame]866<p>It's also possible to use "let" expressions inside multiclasses, providing
867more ways to factor out commonality from the records, specially if using
868several levels of multiclass instanciations. This also avoids the need of using
869"let" expressions within subsequent records inside a multiclass.</p>
870
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]871<pre class="doc_code">
Bruno Cardoso Lopesee65db32010-06-10 02:42:59 +0000[diff] [blame]872<b>multiclass </b>basic_r&lt;bits&lt;4&gt; opc&gt; {
873 <b>let </b>Predicates = [HasSSE2] in {
874 <b>def </b>rr : Instruction&lt;opc, "rr"&gt;;
875 <b>def </b>rm : Instruction&lt;opc, "rm"&gt;;
876 }
877 <b>let </b>Predicates = [HasSSE3] in
878 <b>def </b>rx : Instruction&lt;opc, "rx"&gt;;
879}
880
881<b>multiclass </b>basic_ss&lt;bits&lt;4&gt; opc&gt; {
882 <b>let </b>IsDouble = 0 in
883 <b>defm </b>SS : basic_r&lt;opc&gt;;
884
885 <b>let </b>IsDouble = 1 in
886 <b>defm </b>SD : basic_r&lt;opc&gt;;
887}
888
889<b>defm </b>ADD : basic_ss&lt;0xf&gt;;
890</pre>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]891</div>
892
David Greenecebb4ee2012-02-22 16:09:41 +0000[diff] [blame]893<!-- -------------------------------------------------------------------------->
894<h4>
895 <a name="foreach">Looping</a>
896</h4>
897
898<div>
899<p>TableGen supports the '<tt>foreach</tt>' block, which textually replicates
900the loop body, substituting iterator values for iterator references in the
901body. Example:</p>
902
903<div class="doc_code">
904<pre>
905<b>foreach</b> i = [0, 1, 2, 3] in {
906 <b>def</b> R#i : Register&lt;...&gt;;
907 <b>def</b> F#i : Register&lt;...&gt;;
908}
909</pre>
910</div>
911
912<p>This will create objects <tt>R0</tt>, <tt>R1</tt>, <tt>R2</tt> and
913<tt>R3</tt>. <tt>foreach</tt> blocks may be nested. If there is only
914one item in the body the braces may be elided:</p>
915
916<div class="doc_code">
917<pre>
918<b>foreach</b> i = [0, 1, 2, 3] in
919 <b>def</b> R#i : Register&lt;...&gt;;
920
921</pre>
922</div>
923
924</div>
925
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]926</div>
927
928</div>
929
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]930<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]931<h2><a name="codegen">Code Generator backend info</a></h2>
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]932<!-- *********************************************************************** -->
933
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]934<div>
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]935
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]936<p>Expressions used by code generator to describe instructions and isel
937patterns:</p>
938
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]939<dl>
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]940<dt><tt>(implicit a)</tt></dt>
941 <dd>an implicitly defined physical register. This tells the dag instruction
942 selection emitter the input pattern's extra definitions matches implicit
943 physical register definitions.</dd>
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]944</dl>
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]945</div>
946
947<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]948<h2><a name="backends">TableGen backends</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]949<!-- *********************************************************************** -->
950
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]951<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]952
953<p>TODO: How they work, how to write one. This section should not contain
954details about any particular backend, except maybe -print-enums as an example.
955This should highlight the APIs in <tt>TableGen/Record.h</tt>.</p>
956
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]957</div>
958
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]959<!-- *********************************************************************** -->
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]960
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]961<hr>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]962<address>
963 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]964 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]965 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]966 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]967
968 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]969 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]970 Last modified: $Date$
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]971</address>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]972
973</body>
974</html>