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5 <title>TableGen Fundamentals</title>
6 <link rel="stylesheet" href="llvm.css" type="text/css">
7</head>
8<body>
9
10<div class="doc_title">TableGen Fundamentals</div>
11
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]12<div class="doc_text">
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]13<ul>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]14 <li><a href="#introduction">Introduction</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]15 <ol>
16 <li><a href="#concepts">Basic concepts</a></li>
17 <li><a href="#example">An example record</a></li>
18 <li><a href="#running">Running TableGen</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]19 </ol></li>
20 <li><a href="#syntax">TableGen syntax</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]21 <ol>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]22 <li><a href="#primitives">TableGen primitives</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]23 <ol>
24 <li><a href="#comments">TableGen comments</a></li>
25 <li><a href="#types">The TableGen type system</a></li>
26 <li><a href="#values">TableGen values and expressions</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]27 </ol></li>
28 <li><a href="#classesdefs">Classes and definitions</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]29 <ol>
30 <li><a href="#valuedef">Value definitions</a></li>
31 <li><a href="#recordlet">'let' expressions</a></li>
32 <li><a href="#templateargs">Class template arguments</a></li>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]33 <li><a href="#multiclass">Multiclass definitions and instances</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]34 </ol></li>
35 <li><a href="#filescope">File scope entities</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]36 <ol>
37 <li><a href="#include">File inclusion</a></li>
38 <li><a href="#globallet">'let' expressions</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]39 </ol></li>
40 </ol></li>
41 <li><a href="#backends">TableGen backends</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]42 <ol>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]43 <li><a href="#">todo</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]44 </ol></li>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]45</ul>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]46</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]47
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]48<div class="doc_author">
49 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p>
50</div>
51
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]52<!-- *********************************************************************** -->
53<div class="doc_section"><a name="introduction">Introduction</a></div>
54<!-- *********************************************************************** -->
55
56<div class="doc_text">
57
58<p>TableGen's purpose is to help a human develop and maintain records of
59domain-specific information. Because there may be a large number of these
60records, it is specifically designed to allow writing flexible descriptions and
61for common features of these records to be factored out. This reduces the
62amount of duplication in the description, reduces the chance of error, and
63makes it easier to structure domain specific information.</p>
64
65<p>The core part of TableGen <a href="#syntax">parses a file</a>, instantiates
66the declarations, and hands the result off to a domain-specific "<a
67href="#backends">TableGen backend</a>" for processing. The current major user
Chris Lattner1aab3272004-07-26 21:16:55 +0000[diff] [blame]68of TableGen is the <a href="CodeGenerator.html">LLVM code generator</a>.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]69
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]70<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]71find an emacs "TableGen mode" and a vim language file in the
72<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]73distribution, respectively.</p>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]74
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]75</div>
76
77<!-- ======================================================================= -->
Jim Laskeyf1b5adb2006-09-09 09:10:37 +0000[diff] [blame]78<div class="doc_subsection"><a name="concepts">Basic concepts</a></div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]79
80<div class="doc_text">
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<!-- ======================================================================= -->
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]115<div class="doc_subsection"><a name="example">An example record</a></div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]116
117<div class="doc_text">
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;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]147 <b>bit</b> isTwoAddress = 1;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]148 <b>bit</b> isConvertibleToThreeAddress = 1;
149 <b>bit</b> isCommutable = 1;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]150 <b>bit</b> isTerminator = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]151 <b>bit</b> isReMaterializable = 0;
152 <b>bit</b> isPredicable = 0;
153 <b>bit</b> hasDelaySlot = 0;
Dan Gohman533297b2009-10-29 18:10:34 +0000[diff] [blame]154 <b>bit</b> usesCustomInserter = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]155 <b>bit</b> hasCtrlDep = 0;
156 <b>bit</b> isNotDuplicable = 0;
157 <b>bit</b> hasSideEffects = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]158 <b>bit</b> neverHasSideEffects = 0;
159 InstrItinClass Itinerary = NoItinerary;
160 <b>string</b> Constraints = "";
161 <b>string</b> DisableEncoding = "";
162 <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]163 Format Form = MRMDestReg;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]164 <b>bits</b>&lt;6&gt; FormBits = { 0, 0, 0, 0, 1, 1 };
165 ImmType ImmT = NoImm;
166 <b>bits</b>&lt;3&gt; ImmTypeBits = { 0, 0, 0 };
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]167 <b>bit</b> hasOpSizePrefix = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]168 <b>bit</b> hasAdSizePrefix = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]169 <b>bits</b>&lt;4&gt; Prefix = { 0, 0, 0, 0 };
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]170 <b>bit</b> hasREX_WPrefix = 0;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]171 FPFormat FPForm = ?;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]172 <b>bits</b>&lt;3&gt; FPFormBits = { 0, 0, 0 };
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]173}
174...
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]175</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]176</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]177
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]178<p>This definition corresponds to a 32-bit register-register add instruction in
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]179the X86. The string after the '<tt>def</tt>' string indicates the name of the
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]180record&mdash;"<tt>ADD32rr</tt>" in this case&mdash;and the comment at the end of
181the line indicates the superclasses of the definition. The body of the record
182contains all of the data that TableGen assembled for the record, indicating that
183the instruction is part of the "X86" namespace, the pattern indicating how the
184the instruction should be emitted into the assembly file, that it is a
185two-address instruction, has a particular encoding, etc. The contents and
186semantics of the information in the record is specific to the needs of the X86
187backend, and is only shown as an example.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]188
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]189<p>As you can see, a lot of information is needed for every instruction
190supported by the code generator, and specifying it all manually would be
Dan Gohman8ff4b432010-02-26 02:15:17 +0000[diff] [blame]191unmaintainable, prone to bugs, and tiring to do in the first place. Because we
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]192are using TableGen, all of the information was derived from the following
193definition:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]194
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]195<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]196<pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]197let Defs = [EFLAGS],
198 isCommutable = 1, <i>// X = ADD Y,Z --&gt; X = ADD Z,Y</i>
199 isConvertibleToThreeAddress = 1 <b>in</b> <i>// Can transform into LEA.</i>
200def ADD32rr : I&lt;0x01, MRMDestReg, (outs GR32:$dst),
201 (ins GR32:$src1, GR32:$src2),
202 "add{l}\t{$src2, $dst|$dst, $src2}",
203 [(set GR32:$dst, (add GR32:$src1, GR32:$src2))]&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]204</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]205</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]206
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]207<p>This definition makes use of the custom class <tt>I</tt> (extended from the
208custom class <tt>X86Inst</tt>), which is defined in the X86-specific TableGen
209file, to factor out the common features that instructions of its class share. A
210key feature of TableGen is that it allows the end-user to define the
211abstractions they prefer to use when describing their information.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]212
213</div>
214
215<!-- ======================================================================= -->
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]216<div class="doc_subsection"><a name="running">Running TableGen</a></div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]217
218<div class="doc_text">
219
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]220<p>TableGen runs just like any other LLVM tool. The first (optional) argument
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]221specifies the file to read. If a filename is not specified, <tt>tblgen</tt>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]222reads from standard input.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]223
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]224<p>To be useful, one of the <a href="#backends">TableGen backends</a> must be
225used. These backends are selectable on the command line (type '<tt>tblgen
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]226-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]227that subclass a particular type (which can be useful for building up an enum
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]228list of these records), use the <tt>-print-enums</tt> option:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]229
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]230<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]231<pre>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]232$ tblgen X86.td -print-enums -class=Register
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]233AH, AL, AX, BH, BL, BP, BPL, BX, CH, CL, CX, DH, DI, DIL, DL, DX, EAX, EBP, EBX,
234ECX, EDI, EDX, EFLAGS, EIP, ESI, ESP, FP0, FP1, FP2, FP3, FP4, FP5, FP6, IP,
235MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7, R10, R10B, R10D, R10W, R11, R11B, R11D,
236R11W, R12, R12B, R12D, R12W, R13, R13B, R13D, R13W, R14, R14B, R14D, R14W, R15,
237R15B, R15D, R15W, R8, R8B, R8D, R8W, R9, R9B, R9D, R9W, RAX, RBP, RBX, RCX, RDI,
238RDX, RIP, RSI, RSP, SI, SIL, SP, SPL, ST0, ST1, ST2, ST3, ST4, ST5, ST6, ST7,
239XMM0, XMM1, XMM10, XMM11, XMM12, XMM13, XMM14, XMM15, XMM2, XMM3, XMM4, XMM5,
240XMM6, XMM7, XMM8, XMM9,
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]241
242$ tblgen X86.td -print-enums -class=Instruction
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]243ABS_F, ABS_Fp32, ABS_Fp64, ABS_Fp80, ADC32mi, ADC32mi8, ADC32mr, ADC32ri,
244ADC32ri8, ADC32rm, ADC32rr, ADC64mi32, ADC64mi8, ADC64mr, ADC64ri32, ADC64ri8,
245ADC64rm, ADC64rr, ADD16mi, ADD16mi8, ADD16mr, ADD16ri, ADD16ri8, ADD16rm,
246ADD16rr, ADD32mi, ADD32mi8, ADD32mr, ADD32ri, ADD32ri8, ADD32rm, ADD32rr,
247ADD64mi32, ADD64mi8, ADD64mr, ADD64ri32, ...
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]248</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]249</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]250
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]251<p>The default backend prints out all of the records, as described <a
252href="#example">above</a>.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]253
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]254<p>If you plan to use TableGen, you will most likely have to <a
255href="#backends">write a backend</a> that extracts the information specific to
256what you need and formats it in the appropriate way.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]257
258</div>
259
260
261<!-- *********************************************************************** -->
262<div class="doc_section"><a name="syntax">TableGen syntax</a></div>
263<!-- *********************************************************************** -->
264
265<div class="doc_text">
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]266
267<p>TableGen doesn't care about the meaning of data (that is up to the backend to
268define), but it does care about syntax, and it enforces a simple type system.
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]269This section describes the syntax and the constructs allowed in a TableGen file.
270</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]271
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]272</div>
273
274<!-- ======================================================================= -->
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]275<div class="doc_subsection"><a name="primitives">TableGen primitives</a></div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]276
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]277<!-- -------------------------------------------------------------------------->
278<div class="doc_subsubsection"><a name="comments">TableGen comments</a></div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]279
280<div class="doc_text">
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]281
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]282<p>TableGen supports BCPL style "<tt>//</tt>" comments, which run to the end of
283the line, and it also supports <b>nestable</b> "<tt>/* */</tt>" comments.</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]284
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]285</div>
286
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]287<!-- -------------------------------------------------------------------------->
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]288<div class="doc_subsubsection">
289 <a name="types">The TableGen type system</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]290</div>
291
292<div class="doc_text">
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]293
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]294<p>TableGen files are strongly typed, in a simple (but complete) type-system.
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]295These types are used to perform automatic conversions, check for errors, and to
296help interface designers constrain the input that they allow. Every <a
297href="#valuedef">value definition</a> is required to have an associated type.
298</p>
299
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]300<p>TableGen supports a mixture of very low-level types (such as <tt>bit</tt>)
301and very high-level types (such as <tt>dag</tt>). This flexibility is what
302allows it to describe a wide range of information conveniently and compactly.
303The TableGen types are:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]304
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]305<dl>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]306<dt><tt><b>bit</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]307 <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]308
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]309<dt><tt><b>int</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]310 <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]311
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]312<dt><tt><b>string</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]313 <dd>The 'string' type represents an ordered sequence of characters of
314 arbitrary length.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]315
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]316<dt><tt><b>bits</b>&lt;n&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]317 <dd>A 'bits' type is an arbitrary, but fixed, size integer that is broken up
318 into individual bits. This type is useful because it can handle some bits
319 being defined while others are undefined.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]320
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]321<dt><tt><b>list</b>&lt;ty&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]322 <dd>This type represents a list whose elements are some other type. The
323 contained type is arbitrary: it can even be another list type.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]324
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]325<dt>Class type</dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]326 <dd>Specifying a class name in a type context means that the defined value
327 must be a subclass of the specified class. This is useful in conjunction with
328 the <b><tt>list</tt></b> type, for example, to constrain the elements of the
329 list to a common base class (e.g., a <tt><b>list</b>&lt;Register&gt;</tt> can
330 only contain definitions derived from the "<tt>Register</tt>" class).</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]331
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]332<dt><tt><b>dag</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]333 <dd>This type represents a nestable directed graph of elements.</dd>
334
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]335<dt><tt><b>code</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]336 <dd>This represents a big hunk of text. NOTE: I don't remember why this is
337 distinct from string!</dd>
338</dl>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]339
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]340<p>To date, these types have been sufficient for describing things that
341TableGen has been used for, but it is straight-forward to extend this list if
342needed.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]343
344</div>
345
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]346<!-- -------------------------------------------------------------------------->
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]347<div class="doc_subsubsection">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]348 <a name="values">TableGen values and expressions</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]349</div>
350
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]351<div class="doc_text">
352
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]353<p>TableGen allows for a pretty reasonable number of different expression forms
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]354when building up values. These forms allow the TableGen file to be written in a
355natural syntax and flavor for the application. The current expression forms
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]356supported include:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]357
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]358<dl>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]359<dt><tt>?</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]360 <dd>uninitialized field</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]361<dt><tt>0b1001011</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]362 <dd>binary integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]363<dt><tt>07654321</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]364 <dd>octal integer value (indicated by a leading 0)</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]365<dt><tt>7</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]366 <dd>decimal integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]367<dt><tt>0x7F</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]368 <dd>hexadecimal integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]369<dt><tt>"foo"</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]370 <dd>string value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]371<dt><tt>[{ ... }]</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]372 <dd>code fragment</dd>
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]373<dt><tt>[ X, Y, Z ]&lt;type&gt;</tt></dt>
374 <dd>list value. &lt;type&gt; is the type of the list
David Greeneccbfb8d2009-06-08 22:38:07 +0000[diff] [blame]375element and is usually optional. In rare cases,
376TableGen is unable to deduce the element type in
377which case the user must specify it explicitly.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]378<dt><tt>{ a, b, c }</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]379 <dd>initializer for a "bits&lt;3&gt;" value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]380<dt><tt>value</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]381 <dd>value reference</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]382<dt><tt>value{17}</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]383 <dd>access to one bit of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]384<dt><tt>value{15-17}</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]385 <dd>access to multiple bits of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]386<dt><tt>DEF</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]387 <dd>reference to a record definition</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]388<dt><tt>CLASS&lt;val list&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]389 <dd>reference to a new anonymous definition of CLASS with the specified
390 template arguments.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]391<dt><tt>X.Y</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]392 <dd>reference to the subfield of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]393<dt><tt>list[4-7,17,2-3]</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]394 <dd>A slice of the 'list' list, including elements 4,5,6,7,17,2, and 3 from
395 it. Elements may be included multiple times.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]396<dt><tt>(DEF a, b)</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]397 <dd>a dag value. The first element is required to be a record definition, the
398 remaining elements in the list may be arbitrary other values, including nested
399 `<tt>dag</tt>' values.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]400<dt><tt>!strconcat(a, b)</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]401 <dd>A string value that is the result of concatenating the 'a' and 'b'
402 strings.</dd>
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]403<dt><tt>!cast&lt;type&gt;(a)</tt></dt>
David Greenee6c27de2009-05-14 21:22:49 +0000[diff] [blame]404 <dd>A symbol of type <em>type</em> obtained by looking up the string 'a' in
405the symbol table. If the type of 'a' does not match <em>type</em>, TableGen
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]406aborts 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]407be an object defined by a 'def' construct.</dd>
David Greene3f47c292009-04-23 21:27:58 +0000[diff] [blame]408<dt><tt>!nameconcat&lt;type&gt;(a, b)</tt></dt>
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]409 <dd>Shorthand for !cast&lt;type&gt;(!strconcat(a, b))</dd>
David Greene4afc5092009-05-14 21:54:42 +0000[diff] [blame]410<dt><tt>!subst(a, b, c)</tt></dt>
411 <dd>If 'a' and 'b' are of string type or are symbol references, substitute
412'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]413<dt><tt>!foreach(a, b, c)</tt></dt>
414 <dd>For each member 'b' of dag or list 'a' apply operator 'c.' 'b' is a
415dummy variable that should be declared as a member variable of an instantiated
416class. This operation is analogous to $(foreach) in GNU make.</dd>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]417<dt><tt>!car(a)</tt></dt>
418 <dd>The first element of list 'a.'</dd>
419<dt><tt>!cdr(a)</tt></dt>
420 <dd>The 2nd-N elements of list 'a.'</dd>
421<dt><tt>!null(a)</tt></dt>
422 <dd>An integer {0,1} indicating whether list 'a' is empty.</dd>
David Greene9bea7c82009-05-14 23:26:46 +0000[diff] [blame]423<dt><tt>!if(a,b,c)</tt></dt>
424 <dd>'b' if the result of integer operator 'a' is nonzero, 'c' otherwise.</dd>
David Greene6786d5e2010-01-05 19:11:42 +0000[diff] [blame]425<dt><tt>!eq(a,b)</tt></dt>
426 <dd>Integer one if string a is equal to string b, zero otherwise. This
427 only operates on string objects. Use !cast<string> to compare other
428 types of objects.</dd>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]429</dl>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]430
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]431<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]432for different types. These rules allow you to assign a value like "<tt>7</tt>"
433to a "<tt>bits&lt;4&gt;</tt>" value, for example.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]434
435</div>
436
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]437<!-- ======================================================================= -->
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]438<div class="doc_subsection">
439 <a name="classesdefs">Classes and definitions</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]440</div>
441
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]442<div class="doc_text">
443
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]444<p>As mentioned in the <a href="#concepts">intro</a>, classes and definitions
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]445(collectively known as 'records') in TableGen are the main high-level unit of
446information that TableGen collects. Records are defined with a <tt>def</tt> or
447<tt>class</tt> keyword, the record name, and an optional list of "<a
Misha Brukman179bf4b2004-06-03 23:42:24 +0000[diff] [blame]448href="#templateargs">template arguments</a>". If the record has superclasses,
Jeff Cohen0b81cda2005-10-24 16:54:55 +0000[diff] [blame]449they are specified as a comma separated list that starts with a colon character
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]450("<tt>:</tt>"). If <a href="#valuedef">value definitions</a> or <a
451href="#recordlet">let expressions</a> are needed for the class, they are
452enclosed in curly braces ("<tt>{}</tt>"); otherwise, the record ends with a
453semicolon.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]454
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]455<p>Here is a simple TableGen file:</p>
456
457<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]458<pre>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]459<b>class</b> C { <b>bit</b> V = 1; }
460<b>def</b> X : C;
461<b>def</b> Y : C {
462 <b>string</b> Greeting = "hello";
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]463}
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]464</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]465</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]466
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]467<p>This example defines two definitions, <tt>X</tt> and <tt>Y</tt>, both of
468which derive from the <tt>C</tt> class. Because of this, they both get the
469<tt>V</tt> bit value. The <tt>Y</tt> definition also gets the Greeting member
470as well.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]471
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]472<p>In general, classes are useful for collecting together the commonality
473between a group of records and isolating it in a single place. Also, classes
474permit the specification of default values for their subclasses, allowing the
475subclasses to override them as they wish.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]476
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]477</div>
478
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]479<!---------------------------------------------------------------------------->
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]480<div class="doc_subsubsection">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]481 <a name="valuedef">Value definitions</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]482</div>
483
484<div class="doc_text">
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]485
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]486<p>Value definitions define named entries in records. A value must be defined
John Criswellaa55c8c2004-02-12 18:11:53 +0000[diff] [blame]487before it can be referred to as the operand for another value definition or
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]488before the value is reset with a <a href="#recordlet">let expression</a>. A
489value is defined by specifying a <a href="#types">TableGen type</a> and a name.
490If an initial value is available, it may be specified after the type with an
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]491equal sign. Value definitions require terminating semicolons.</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]492
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]493</div>
494
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]495<!-- -------------------------------------------------------------------------->
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]496<div class="doc_subsubsection">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]497 <a name="recordlet">'let' expressions</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]498</div>
499
500<div class="doc_text">
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]501
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]502<p>A record-level let expression is used to change the value of a value
503definition in a record. This is primarily useful when a superclass defines a
504value that a derived class or definition wants to override. Let expressions
505consist of the '<tt>let</tt>' keyword followed by a value name, an equal sign
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]506("<tt>=</tt>"), and a new value. For example, a new class could be added to the
507example above, redefining the <tt>V</tt> field for all of its subclasses:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]508
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]509<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]510<pre>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]511<b>class</b> D : C { let V = 0; }
512<b>def</b> Z : D;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]513</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]514</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]515
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]516<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]517value, despite the fact that it derives (indirectly) from the <tt>C</tt> class,
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]518because the <tt>D</tt> class overrode its value.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]519
520</div>
521
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]522<!-- -------------------------------------------------------------------------->
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]523<div class="doc_subsubsection">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]524 <a name="templateargs">Class template arguments</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]525</div>
526
527<div class="doc_text">
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]528
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]529<p>TableGen permits the definition of parameterized classes as well as normal
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]530concrete classes. Parameterized TableGen classes specify a list of variable
531bindings (which may optionally have defaults) that are bound when used. Here is
532a simple example:</p>
533
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]534<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]535<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]536<b>class</b> FPFormat&lt;<b>bits</b>&lt;3&gt; val&gt; {
537 <b>bits</b>&lt;3&gt; Value = val;
538}
539<b>def</b> NotFP : FPFormat&lt;0&gt;;
540<b>def</b> ZeroArgFP : FPFormat&lt;1&gt;;
541<b>def</b> OneArgFP : FPFormat&lt;2&gt;;
542<b>def</b> OneArgFPRW : FPFormat&lt;3&gt;;
543<b>def</b> TwoArgFP : FPFormat&lt;4&gt;;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]544<b>def</b> CompareFP : FPFormat&lt;5&gt;;
545<b>def</b> CondMovFP : FPFormat&lt;6&gt;;
546<b>def</b> SpecialFP : FPFormat&lt;7&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]547</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]548</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]549
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]550<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]551a list of "enumeration values", each with a "<tt>Value</tt>" field set to the
552specified integer.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]553
554<p>The more esoteric forms of <a href="#values">TableGen expressions</a> are
555useful in conjunction with template arguments. As an example:</p>
556
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]557<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]558<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]559<b>class</b> ModRefVal&lt;<b>bits</b>&lt;2&gt; val&gt; {
560 <b>bits</b>&lt;2&gt; Value = val;
561}
562
563<b>def</b> None : ModRefVal&lt;0&gt;;
564<b>def</b> Mod : ModRefVal&lt;1&gt;;
565<b>def</b> Ref : ModRefVal&lt;2&gt;;
566<b>def</b> ModRef : ModRefVal&lt;3&gt;;
567
568<b>class</b> Value&lt;ModRefVal MR&gt; {
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]569 <i>// Decode some information into a more convenient format, while providing
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]570 // a nice interface to the user of the "Value" class.</i>
571 <b>bit</b> isMod = MR.Value{0};
572 <b>bit</b> isRef = MR.Value{1};
573
574 <i>// other stuff...</i>
575}
576
577<i>// Example uses</i>
578<b>def</b> bork : Value&lt;Mod&gt;;
579<b>def</b> zork : Value&lt;Ref&gt;;
580<b>def</b> hork : Value&lt;ModRef&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]581</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]582</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]583
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]584<p>This is obviously a contrived example, but it shows how template arguments
585can 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]586actual internal data representation expected by the class. In this case,
587running <tt>tblgen</tt> on the example prints the following definitions:</p>
588
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]589<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]590<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]591<b>def</b> bork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]592 <b>bit</b> isMod = 1;
593 <b>bit</b> isRef = 0;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]594}
595<b>def</b> hork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]596 <b>bit</b> isMod = 1;
597 <b>bit</b> isRef = 1;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]598}
599<b>def</b> zork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]600 <b>bit</b> isMod = 0;
601 <b>bit</b> isRef = 1;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]602}
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]603</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]604</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]605
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]606<p> This shows that TableGen was able to dig into the argument and extract a
607piece of information that was requested by the designer of the "Value" class.
608For more realistic examples, please see existing users of TableGen, such as the
609X86 backend.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]610
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]611</div>
612
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]613<!-- -------------------------------------------------------------------------->
614<div class="doc_subsubsection">
615 <a name="multiclass">Multiclass definitions and instances</a>
616</div>
617
618<div class="doc_text">
619
620<p>
621While classes with template arguments are a good way to factor commonality
622between two instances of a definition, multiclasses allow a convenient notation
623for defining multiple definitions at once (instances of implicitly constructed
624classes). For example, consider an 3-address instruction set whose instructions
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]625come in two forms: "<tt>reg = reg op reg</tt>" and "<tt>reg = reg op imm</tt>"
626(e.g. SPARC). In this case, you'd like to specify in one place that this
627commonality exists, then in a separate place indicate what all the ops are.
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]628</p>
629
630<p>
631Here is an example TableGen fragment that shows this idea:
632</p>
633
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]634<div class="doc_code">
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]635<pre>
636<b>def</b> ops;
637<b>def</b> GPR;
638<b>def</b> Imm;
639<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
640
641<b>multiclass</b> ri_inst&lt;<b>int</b> opc, <b>string</b> asmstr&gt; {
642 def _rr : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
643 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
644 def _ri : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
645 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
646}
647
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]648<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]649<b>defm</b> ADD : ri_inst&lt;0b111, "add"&gt;;
650<b>defm</b> SUB : ri_inst&lt;0b101, "sub"&gt;;
651<b>defm</b> MUL : ri_inst&lt;0b100, "mul"&gt;;
652...
653</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]654</div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]655
Chris Lattnere7173e12006-09-01 22:01:36 +0000[diff] [blame]656<p>The name of the resultant definitions has the multidef fragment names
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]657 appended to them, so this defines <tt>ADD_rr</tt>, <tt>ADD_ri</tt>,
David Greene56546132009-04-22 22:17:51 +0000[diff] [blame]658 <tt>SUB_rr</tt>, etc. A defm may inherit from multiple multiclasses,
659 instantiating definitions from each multiclass. Using a multiclass
660 this way is exactly equivalent to instantiating the classes multiple
661 times yourself, e.g. by writing:</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]662
663<div class="doc_code">
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]664<pre>
665<b>def</b> ops;
666<b>def</b> GPR;
667<b>def</b> Imm;
668<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
669
670<b>class</b> rrinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
671 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
672 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
673
674<b>class</b> riinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
675 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
676 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
677
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]678<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]679<b>def</b> ADD_rr : rrinst&lt;0b111, "add"&gt;;
680<b>def</b> ADD_ri : riinst&lt;0b111, "add"&gt;;
681<b>def</b> SUB_rr : rrinst&lt;0b101, "sub"&gt;;
682<b>def</b> SUB_ri : riinst&lt;0b101, "sub"&gt;;
683<b>def</b> MUL_rr : rrinst&lt;0b100, "mul"&gt;;
684<b>def</b> MUL_ri : riinst&lt;0b100, "mul"&gt;;
685...
686</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]687</div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]688
689</div>
690
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]691<!-- ======================================================================= -->
692<div class="doc_subsection">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]693 <a name="filescope">File scope entities</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]694</div>
695
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]696<!-- -------------------------------------------------------------------------->
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]697<div class="doc_subsubsection">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]698 <a name="include">File inclusion</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]699</div>
700
701<div class="doc_text">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]702<p>TableGen supports the '<tt>include</tt>' token, which textually substitutes
703the specified file in place of the include directive. The filename should be
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]704specified as a double quoted string immediately after the '<tt>include</tt>'
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]705keyword. Example:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]706
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]707<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]708<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]709<b>include</b> "foo.td"
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]710</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]711</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]712
713</div>
714
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]715<!-- -------------------------------------------------------------------------->
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]716<div class="doc_subsubsection">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]717 <a name="globallet">'let' expressions</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]718</div>
719
720<div class="doc_text">
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]721
722<p>"Let" expressions at file scope are similar to <a href="#recordlet">"let"
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]723expressions within a record</a>, except they can specify a value binding for
724multiple records at a time, and may be useful in certain other cases.
725File-scope let expressions are really just another way that TableGen allows the
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]726end-user to factor out commonality from the records.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]727
Jeff Cohen0b81cda2005-10-24 16:54:55 +0000[diff] [blame]728<p>File-scope "let" expressions take a comma-separated list of bindings to
Matthijs Kooijman94199da2008-10-20 08:45:34 +0000[diff] [blame]729apply, and one or more records to bind the values in. Here are some
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]730examples:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]731
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]732<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]733<pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]734<b>let</b> isTerminator = 1, isReturn = 1, isBarrier = 1, hasCtrlDep = 1 <b>in</b>
735 <b>def</b> RET : I&lt;0xC3, RawFrm, (outs), (ins), "ret", [(X86retflag 0)]&gt;;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]736
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]737<b>let</b> isCall = 1 <b>in</b>
738 <i>// All calls clobber the non-callee saved registers...</i>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]739 <b>let</b> Defs = [EAX, ECX, EDX, FP0, FP1, FP2, FP3, FP4, FP5, FP6, ST0,
740 MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7,
741 XMM0, XMM1, XMM2, XMM3, XMM4, XMM5, XMM6, XMM7, EFLAGS] <b>in</b> {
Dan Gohman364a39f2008-10-14 17:00:38 +0000[diff] [blame]742 <b>def</b> CALLpcrel32 : Ii32&lt;0xE8, RawFrm, (outs), (ins i32imm:$dst,variable_ops),
743 "call\t${dst:call}", []&gt;;
744 <b>def</b> CALL32r : I&lt;0xFF, MRM2r, (outs), (ins GR32:$dst, variable_ops),
745 "call\t{*}$dst", [(X86call GR32:$dst)]&gt;;
746 <b>def</b> CALL32m : I&lt;0xFF, MRM2m, (outs), (ins i32mem:$dst, variable_ops),
747 "call\t{*}$dst", []&gt;;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]748 }
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]749</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]750</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]751
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]752<p>File-scope "let" expressions are often useful when a couple of definitions
753need 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]754opened, as in the case with the <tt>CALL*</tt> instructions above.</p>
755
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]756</div>
757
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]758<!-- *********************************************************************** -->
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]759<div class="doc_section"><a name="codegen">Code Generator backend info</a></div>
760<!-- *********************************************************************** -->
761
762<p>Expressions used by code generator to describe instructions and isel
763patterns:</p>
764
765<div class="doc_text">
766
767<dt><tt>(implicit a)</tt></dt>
768 <dd>an implicitly defined physical register. This tells the dag instruction
769 selection emitter the input pattern's extra definitions matches implicit
770 physical register definitions.</dd>
771<dt><tt>(parallel (a), (b))</tt></dt>
772 <dd>a list of dags specifying parallel operations which map to the same
773 instruction.</dd>
774
775</div>
776
777<!-- *********************************************************************** -->
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]778<div class="doc_section"><a name="backends">TableGen backends</a></div>
779<!-- *********************************************************************** -->
780
781<div class="doc_text">
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]782
783<p>TODO: How they work, how to write one. This section should not contain
784details about any particular backend, except maybe -print-enums as an example.
785This should highlight the APIs in <tt>TableGen/Record.h</tt>.</p>
786
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]787</div>
788
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]789<!-- *********************************************************************** -->
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]790
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]791<hr>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]792<address>
793 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]794 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]795 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]796 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]797
798 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]799 <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]800 Last modified: $Date$
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]801</address>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]802
803</body>
804</html>