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5 <title>TableGen Fundamentals</title>
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7</head>
8<body>
9
10<div class="doc_title">TableGen Fundamentals</div>
11
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]12<div class="doc_text">
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]13<ul>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]14 <li><a href="#introduction">Introduction</a>
Chris Lattner149a2492004-02-06 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]19 </ol></li>
20 <li><a href="#syntax">TableGen syntax</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]21 <ol>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]22 <li><a href="#primitives">TableGen primitives</a>
Chris Lattner149a2492004-02-06 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]27 </ol></li>
28 <li><a href="#classesdefs">Classes and definitions</a>
Chris Lattner149a2492004-02-06 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 Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]33 <li><a href="#multiclass">Multiclass definitions and instances</a></li>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]34 </ol></li>
35 <li><a href="#filescope">File scope entities</a>
Chris Lattner149a2492004-02-06 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]39 </ol></li>
40 </ol></li>
41 <li><a href="#backends">TableGen backends</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]42 <ol>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]43 <li><a href="#">todo</a></li>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]44 </ol></li>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]45</ul>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]46</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]47
Chris Lattner020e1fc2004-05-23 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 Lattner149a2492004-02-06 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 Lattner7f500132004-07-26 21:16:55 +0000[diff] [blame]68of TableGen is the <a href="CodeGenerator.html">LLVM code generator</a>.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]69
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]73distribution, respectively.</p>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]74
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]75</div>
76
77<!-- ======================================================================= -->
Jim Laskeyea05a062006-09-09 09:10:37 +0000[diff] [blame]78<div class="doc_subsection"><a name="concepts">Basic concepts</a></div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]79
80<div class="doc_text">
81
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]84
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]90taken care of and are fixed by TableGen.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]91
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]95
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]98abstractions for either the domain they are targeting (such as "Register",
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]105
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]106<p><b>TableGen multiclasses</b> are groups of abstract records that are
David Greene753ed8f2009-04-22 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 Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]111
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]112</div>
113
114<!-- ======================================================================= -->
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]115<div class="doc_subsection"><a name="example">An example record</a></div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]116
117<div class="doc_text">
118
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]123
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]124<div class="doc_code">
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]125<pre>
126...
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]127<b>def</b> ADD32rr { <i>// Instruction X86Inst I</i>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]128 <b>string</b> Namespace = "X86";
Bill Wendling1a19af92008-02-12 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 Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]133 <b>list</b>&lt;Register&gt; Uses = [];
Bill Wendling1a19af92008-02-12 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 Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]138 <b>bit</b> isReturn = 0;
139 <b>bit</b> isBranch = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]140 <b>bit</b> isIndirectBranch = 0;
141 <b>bit</b> isBarrier = 0;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]142 <b>bit</b> isCall = 0;
Dan Gohman69cc2cb2008-12-03 18:15:48 +0000[diff] [blame]143 <b>bit</b> canFoldAsLoad = 0;
Bill Wendling1a19af92008-02-12 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 Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]147 <b>bit</b> isTwoAddress = 1;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]148 <b>bit</b> isConvertibleToThreeAddress = 1;
149 <b>bit</b> isCommutable = 1;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]150 <b>bit</b> isTerminator = 0;
Bill Wendling1a19af92008-02-12 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 Gohman453d64c2009-10-29 18:10:34 +0000[diff] [blame]154 <b>bit</b> usesCustomInserter = 0;
Bill Wendling1a19af92008-02-12 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 Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]163 Format Form = MRMDestReg;
Bill Wendling1a19af92008-02-12 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 Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]167 <b>bit</b> hasOpSizePrefix = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]168 <b>bit</b> hasAdSizePrefix = 0;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]169 <b>bits</b>&lt;4&gt; Prefix = { 0, 0, 0, 0 };
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]170 <b>bit</b> hasREX_WPrefix = 0;
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]171 FPFormat FPForm = ?;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]172 <b>bits</b>&lt;3&gt; FPFormBits = { 0, 0, 0 };
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]173}
174...
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]175</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]176</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]177
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]178<p>This definition corresponds to a 32-bit register-register add instruction in
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]179the X86. The string after the '<tt>def</tt>' string indicates the name of the
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]188
Misha Brukman692cec02004-05-12 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 Gohman5aa39192010-02-26 02:15:17 +0000[diff] [blame]191unmaintainable, prone to bugs, and tiring to do in the first place. Because we
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]192are using TableGen, all of the information was derived from the following
193definition:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]194
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]195<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]196<pre>
Bill Wendling1a19af92008-02-12 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]204</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]205</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]206
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]212
213</div>
214
215<!-- ======================================================================= -->
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]216<div class="doc_subsection"><a name="running">Running TableGen</a></div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]217
218<div class="doc_text">
219
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]220<p>TableGen runs just like any other LLVM tool. The first (optional) argument
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]221specifies the file to read. If a filename is not specified, <tt>tblgen</tt>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]222reads from standard input.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]223
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]226-help</tt>' for a list). For example, to get a list of all of the definitions
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]227that subclass a particular type (which can be useful for building up an enum
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]228list of these records), use the <tt>-print-enums</tt> option:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]229
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]230<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]231<pre>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]232$ tblgen X86.td -print-enums -class=Register
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]241
242$ tblgen X86.td -print-enums -class=Instruction
Bill Wendling1a19af92008-02-12 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]248</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]249</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]250
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]253
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 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 Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]269This section describes the syntax and the constructs allowed in a TableGen file.
270</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]271
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]272</div>
273
274<!-- ======================================================================= -->
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]275<div class="doc_subsection"><a name="primitives">TableGen primitives</a></div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]276
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]277<!-- -------------------------------------------------------------------------->
278<div class="doc_subsubsection"><a name="comments">TableGen comments</a></div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]279
280<div class="doc_text">
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]281
Chris Lattner149a2492004-02-06 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]284
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]285</div>
286
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]287<!-- -------------------------------------------------------------------------->
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]288<div class="doc_subsubsection">
289 <a name="types">The TableGen type system</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]290</div>
291
292<div class="doc_text">
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]293
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]294<p>TableGen files are strongly typed, in a simple (but complete) type-system.
Chris Lattner149a2492004-02-06 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 Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]304
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]305<dl>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]306<dt><tt><b>bit</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]307 <dd>A 'bit' is a boolean value that can hold either 0 or 1.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]308
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]309<dt><tt><b>int</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]310 <dd>The 'int' type represents a simple 32-bit integer value, such as 5.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]311
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]312<dt><tt><b>string</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]313 <dd>The 'string' type represents an ordered sequence of characters of
314 arbitrary length.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]315
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]316<dt><tt><b>bits</b>&lt;n&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]320
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]321<dt><tt><b>list</b>&lt;ty&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]324
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]325<dt>Class type</dt>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]331
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]332<dt><tt><b>dag</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]333 <dd>This type represents a nestable directed graph of elements.</dd>
334
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]335<dt><tt><b>code</b></tt></dt>
Chris Lattner28175bf2010-04-22 16:45:27 +0000[diff] [blame^]336 <dd>This represents a big hunk of text. This is lexically distinct from
337 string values because it doesn't require escapeing double quotes and other
338 common characters that occur in code.</dd>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]339</dl>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]340
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]341<p>To date, these types have been sufficient for describing things that
342TableGen has been used for, but it is straight-forward to extend this list if
343needed.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]344
345</div>
346
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]347<!-- -------------------------------------------------------------------------->
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]348<div class="doc_subsubsection">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]349 <a name="values">TableGen values and expressions</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]350</div>
351
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]352<div class="doc_text">
353
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]354<p>TableGen allows for a pretty reasonable number of different expression forms
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]355when building up values. These forms allow the TableGen file to be written in a
356natural syntax and flavor for the application. The current expression forms
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]357supported include:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]358
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]359<dl>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]360<dt><tt>?</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]361 <dd>uninitialized field</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]362<dt><tt>0b1001011</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]363 <dd>binary integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]364<dt><tt>07654321</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]365 <dd>octal integer value (indicated by a leading 0)</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]366<dt><tt>7</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]367 <dd>decimal integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]368<dt><tt>0x7F</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]369 <dd>hexadecimal integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]370<dt><tt>"foo"</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]371 <dd>string value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]372<dt><tt>[{ ... }]</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]373 <dd>code fragment</dd>
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]374<dt><tt>[ X, Y, Z ]&lt;type&gt;</tt></dt>
375 <dd>list value. &lt;type&gt; is the type of the list
David Greene26433c22009-06-08 22:38:07 +0000[diff] [blame]376element and is usually optional. In rare cases,
377TableGen is unable to deduce the element type in
378which case the user must specify it explicitly.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]379<dt><tt>{ a, b, c }</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]380 <dd>initializer for a "bits&lt;3&gt;" value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]381<dt><tt>value</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]382 <dd>value reference</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]383<dt><tt>value{17}</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]384 <dd>access to one bit of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]385<dt><tt>value{15-17}</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]386 <dd>access to multiple bits of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]387<dt><tt>DEF</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]388 <dd>reference to a record definition</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]389<dt><tt>CLASS&lt;val list&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]390 <dd>reference to a new anonymous definition of CLASS with the specified
391 template arguments.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]392<dt><tt>X.Y</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]393 <dd>reference to the subfield of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]394<dt><tt>list[4-7,17,2-3]</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]395 <dd>A slice of the 'list' list, including elements 4,5,6,7,17,2, and 3 from
396 it. Elements may be included multiple times.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]397<dt><tt>(DEF a, b)</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]398 <dd>a dag value. The first element is required to be a record definition, the
399 remaining elements in the list may be arbitrary other values, including nested
400 `<tt>dag</tt>' values.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]401<dt><tt>!strconcat(a, b)</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]402 <dd>A string value that is the result of concatenating the 'a' and 'b'
403 strings.</dd>
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]404<dt><tt>!cast&lt;type&gt;(a)</tt></dt>
David Greenee8f3b272009-05-14 21:22:49 +0000[diff] [blame]405 <dd>A symbol of type <em>type</em> obtained by looking up the string 'a' in
406the symbol table. If the type of 'a' does not match <em>type</em>, TableGen
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]407aborts with an error. !cast&lt;string&gt; is a special case in that the argument must
David Greeneefa19612009-06-29 20:05:29 +0000[diff] [blame]408be an object defined by a 'def' construct.</dd>
David Greene0e898862009-04-23 21:27:58 +0000[diff] [blame]409<dt><tt>!nameconcat&lt;type&gt;(a, b)</tt></dt>
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]410 <dd>Shorthand for !cast&lt;type&gt;(!strconcat(a, b))</dd>
David Greene98ed3c72009-05-14 21:54:42 +0000[diff] [blame]411<dt><tt>!subst(a, b, c)</tt></dt>
412 <dd>If 'a' and 'b' are of string type or are symbol references, substitute
413'b' for 'a' in 'c.' This operation is analogous to $(subst) in GNU make.</dd>
David Greenee917fff2009-05-14 22:23:47 +0000[diff] [blame]414<dt><tt>!foreach(a, b, c)</tt></dt>
415 <dd>For each member 'b' of dag or list 'a' apply operator 'c.' 'b' is a
416dummy variable that should be declared as a member variable of an instantiated
417class. This operation is analogous to $(foreach) in GNU make.</dd>
David Greened571b3c2009-05-14 22:38:31 +0000[diff] [blame]418<dt><tt>!car(a)</tt></dt>
419 <dd>The first element of list 'a.'</dd>
420<dt><tt>!cdr(a)</tt></dt>
421 <dd>The 2nd-N elements of list 'a.'</dd>
422<dt><tt>!null(a)</tt></dt>
423 <dd>An integer {0,1} indicating whether list 'a' is empty.</dd>
David Greene3587eed2009-05-14 23:26:46 +0000[diff] [blame]424<dt><tt>!if(a,b,c)</tt></dt>
425 <dd>'b' if the result of integer operator 'a' is nonzero, 'c' otherwise.</dd>
David Greene297bfe62010-01-05 19:11:42 +0000[diff] [blame]426<dt><tt>!eq(a,b)</tt></dt>
427 <dd>Integer one if string a is equal to string b, zero otherwise. This
428 only operates on string objects. Use !cast<string> to compare other
429 types of objects.</dd>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]430</dl>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]431
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]432<p>Note that all of the values have rules specifying how they convert to values
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]433for different types. These rules allow you to assign a value like "<tt>7</tt>"
434to a "<tt>bits&lt;4&gt;</tt>" value, for example.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]435
436</div>
437
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]438<!-- ======================================================================= -->
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]439<div class="doc_subsection">
440 <a name="classesdefs">Classes and definitions</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]441</div>
442
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]443<div class="doc_text">
444
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]445<p>As mentioned in the <a href="#concepts">intro</a>, classes and definitions
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]446(collectively known as 'records') in TableGen are the main high-level unit of
447information that TableGen collects. Records are defined with a <tt>def</tt> or
448<tt>class</tt> keyword, the record name, and an optional list of "<a
Misha Brukman31551592004-06-03 23:42:24 +0000[diff] [blame]449href="#templateargs">template arguments</a>". If the record has superclasses,
Jeff Cohendd24d7c2005-10-24 16:54:55 +0000[diff] [blame]450they are specified as a comma separated list that starts with a colon character
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]451("<tt>:</tt>"). If <a href="#valuedef">value definitions</a> or <a
452href="#recordlet">let expressions</a> are needed for the class, they are
453enclosed in curly braces ("<tt>{}</tt>"); otherwise, the record ends with a
454semicolon.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]455
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]456<p>Here is a simple TableGen file:</p>
457
458<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]459<pre>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]460<b>class</b> C { <b>bit</b> V = 1; }
461<b>def</b> X : C;
462<b>def</b> Y : C {
463 <b>string</b> Greeting = "hello";
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]464}
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]465</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]466</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]467
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]468<p>This example defines two definitions, <tt>X</tt> and <tt>Y</tt>, both of
469which derive from the <tt>C</tt> class. Because of this, they both get the
470<tt>V</tt> bit value. The <tt>Y</tt> definition also gets the Greeting member
471as well.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]472
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]473<p>In general, classes are useful for collecting together the commonality
474between a group of records and isolating it in a single place. Also, classes
475permit the specification of default values for their subclasses, allowing the
476subclasses to override them as they wish.</p>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]477
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]478</div>
479
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]480<!---------------------------------------------------------------------------->
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]481<div class="doc_subsubsection">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]482 <a name="valuedef">Value definitions</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]483</div>
484
485<div class="doc_text">
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]486
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]487<p>Value definitions define named entries in records. A value must be defined
John Criswell407f6d42004-02-12 18:11:53 +0000[diff] [blame]488before it can be referred to as the operand for another value definition or
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]489before the value is reset with a <a href="#recordlet">let expression</a>. A
490value is defined by specifying a <a href="#types">TableGen type</a> and a name.
491If an initial value is available, it may be specified after the type with an
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]492equal sign. Value definitions require terminating semicolons.</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]493
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]494</div>
495
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]496<!-- -------------------------------------------------------------------------->
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]497<div class="doc_subsubsection">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]498 <a name="recordlet">'let' expressions</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]499</div>
500
501<div class="doc_text">
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]502
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]503<p>A record-level let expression is used to change the value of a value
504definition in a record. This is primarily useful when a superclass defines a
505value that a derived class or definition wants to override. Let expressions
506consist of the '<tt>let</tt>' keyword followed by a value name, an equal sign
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]507("<tt>=</tt>"), and a new value. For example, a new class could be added to the
508example above, redefining the <tt>V</tt> field for all of its subclasses:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]509
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]510<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]511<pre>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]512<b>class</b> D : C { let V = 0; }
513<b>def</b> Z : D;
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]514</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]515</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]516
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]517<p>In this case, the <tt>Z</tt> definition will have a zero value for its "V"
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]518value, despite the fact that it derives (indirectly) from the <tt>C</tt> class,
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]519because the <tt>D</tt> class overrode its value.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]520
521</div>
522
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]523<!-- -------------------------------------------------------------------------->
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]524<div class="doc_subsubsection">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]525 <a name="templateargs">Class template arguments</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]526</div>
527
528<div class="doc_text">
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]529
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]530<p>TableGen permits the definition of parameterized classes as well as normal
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]531concrete classes. Parameterized TableGen classes specify a list of variable
532bindings (which may optionally have defaults) that are bound when used. Here is
533a simple example:</p>
534
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]535<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]536<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]537<b>class</b> FPFormat&lt;<b>bits</b>&lt;3&gt; val&gt; {
538 <b>bits</b>&lt;3&gt; Value = val;
539}
540<b>def</b> NotFP : FPFormat&lt;0&gt;;
541<b>def</b> ZeroArgFP : FPFormat&lt;1&gt;;
542<b>def</b> OneArgFP : FPFormat&lt;2&gt;;
543<b>def</b> OneArgFPRW : FPFormat&lt;3&gt;;
544<b>def</b> TwoArgFP : FPFormat&lt;4&gt;;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]545<b>def</b> CompareFP : FPFormat&lt;5&gt;;
546<b>def</b> CondMovFP : FPFormat&lt;6&gt;;
547<b>def</b> SpecialFP : FPFormat&lt;7&gt;;
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]548</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]549</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]550
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]551<p>In this case, template arguments are used as a space efficient way to specify
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]552a list of "enumeration values", each with a "<tt>Value</tt>" field set to the
553specified integer.</p>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]554
555<p>The more esoteric forms of <a href="#values">TableGen expressions</a> are
556useful in conjunction with template arguments. As an example:</p>
557
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]558<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]559<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]560<b>class</b> ModRefVal&lt;<b>bits</b>&lt;2&gt; val&gt; {
561 <b>bits</b>&lt;2&gt; Value = val;
562}
563
564<b>def</b> None : ModRefVal&lt;0&gt;;
565<b>def</b> Mod : ModRefVal&lt;1&gt;;
566<b>def</b> Ref : ModRefVal&lt;2&gt;;
567<b>def</b> ModRef : ModRefVal&lt;3&gt;;
568
569<b>class</b> Value&lt;ModRefVal MR&gt; {
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]570 <i>// Decode some information into a more convenient format, while providing
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]571 // a nice interface to the user of the "Value" class.</i>
572 <b>bit</b> isMod = MR.Value{0};
573 <b>bit</b> isRef = MR.Value{1};
574
575 <i>// other stuff...</i>
576}
577
578<i>// Example uses</i>
579<b>def</b> bork : Value&lt;Mod&gt;;
580<b>def</b> zork : Value&lt;Ref&gt;;
581<b>def</b> hork : Value&lt;ModRef&gt;;
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]582</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]583</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]584
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]585<p>This is obviously a contrived example, but it shows how template arguments
586can be used to decouple the interface provided to the user of the class from the
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]587actual internal data representation expected by the class. In this case,
588running <tt>tblgen</tt> on the example prints the following definitions:</p>
589
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]590<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]591<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]592<b>def</b> bork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]593 <b>bit</b> isMod = 1;
594 <b>bit</b> isRef = 0;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]595}
596<b>def</b> hork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]597 <b>bit</b> isMod = 1;
598 <b>bit</b> isRef = 1;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]599}
600<b>def</b> zork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]601 <b>bit</b> isMod = 0;
602 <b>bit</b> isRef = 1;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]603}
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]604</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]605</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]606
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]607<p> This shows that TableGen was able to dig into the argument and extract a
608piece of information that was requested by the designer of the "Value" class.
609For more realistic examples, please see existing users of TableGen, such as the
610X86 backend.</p>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]611
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]612</div>
613
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]614<!-- -------------------------------------------------------------------------->
615<div class="doc_subsubsection">
616 <a name="multiclass">Multiclass definitions and instances</a>
617</div>
618
619<div class="doc_text">
620
621<p>
622While classes with template arguments are a good way to factor commonality
623between two instances of a definition, multiclasses allow a convenient notation
624for defining multiple definitions at once (instances of implicitly constructed
625classes). For example, consider an 3-address instruction set whose instructions
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]626come in two forms: "<tt>reg = reg op reg</tt>" and "<tt>reg = reg op imm</tt>"
627(e.g. SPARC). In this case, you'd like to specify in one place that this
628commonality exists, then in a separate place indicate what all the ops are.
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]629</p>
630
631<p>
632Here is an example TableGen fragment that shows this idea:
633</p>
634
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]635<div class="doc_code">
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]636<pre>
637<b>def</b> ops;
638<b>def</b> GPR;
639<b>def</b> Imm;
640<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
641
642<b>multiclass</b> ri_inst&lt;<b>int</b> opc, <b>string</b> asmstr&gt; {
643 def _rr : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
644 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
645 def _ri : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
646 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
647}
648
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]649<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]650<b>defm</b> ADD : ri_inst&lt;0b111, "add"&gt;;
651<b>defm</b> SUB : ri_inst&lt;0b101, "sub"&gt;;
652<b>defm</b> MUL : ri_inst&lt;0b100, "mul"&gt;;
653...
654</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]655</div>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]656
Chris Lattner28368122006-09-01 22:01:36 +0000[diff] [blame]657<p>The name of the resultant definitions has the multidef fragment names
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]658 appended to them, so this defines <tt>ADD_rr</tt>, <tt>ADD_ri</tt>,
David Greenef00919a2009-04-22 22:17:51 +0000[diff] [blame]659 <tt>SUB_rr</tt>, etc. A defm may inherit from multiple multiclasses,
660 instantiating definitions from each multiclass. Using a multiclass
661 this way is exactly equivalent to instantiating the classes multiple
662 times yourself, e.g. by writing:</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]663
664<div class="doc_code">
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]665<pre>
666<b>def</b> ops;
667<b>def</b> GPR;
668<b>def</b> Imm;
669<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
670
671<b>class</b> rrinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
672 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
673 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
674
675<b>class</b> riinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
676 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
677 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
678
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]679<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]680<b>def</b> ADD_rr : rrinst&lt;0b111, "add"&gt;;
681<b>def</b> ADD_ri : riinst&lt;0b111, "add"&gt;;
682<b>def</b> SUB_rr : rrinst&lt;0b101, "sub"&gt;;
683<b>def</b> SUB_ri : riinst&lt;0b101, "sub"&gt;;
684<b>def</b> MUL_rr : rrinst&lt;0b100, "mul"&gt;;
685<b>def</b> MUL_ri : riinst&lt;0b100, "mul"&gt;;
686...
687</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]688</div>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]689
690</div>
691
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]692<!-- ======================================================================= -->
693<div class="doc_subsection">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]694 <a name="filescope">File scope entities</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]695</div>
696
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]697<!-- -------------------------------------------------------------------------->
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]698<div class="doc_subsubsection">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]699 <a name="include">File inclusion</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]700</div>
701
702<div class="doc_text">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]703<p>TableGen supports the '<tt>include</tt>' token, which textually substitutes
704the specified file in place of the include directive. The filename should be
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]705specified as a double quoted string immediately after the '<tt>include</tt>'
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]706keyword. Example:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]707
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]708<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]709<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]710<b>include</b> "foo.td"
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]711</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]712</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]713
714</div>
715
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]716<!-- -------------------------------------------------------------------------->
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]717<div class="doc_subsubsection">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]718 <a name="globallet">'let' expressions</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]719</div>
720
721<div class="doc_text">
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]722
723<p>"Let" expressions at file scope are similar to <a href="#recordlet">"let"
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]724expressions within a record</a>, except they can specify a value binding for
725multiple records at a time, and may be useful in certain other cases.
726File-scope let expressions are really just another way that TableGen allows the
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]727end-user to factor out commonality from the records.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]728
Jeff Cohendd24d7c2005-10-24 16:54:55 +0000[diff] [blame]729<p>File-scope "let" expressions take a comma-separated list of bindings to
Matthijs Kooijman3abb3082008-10-20 08:45:34 +0000[diff] [blame]730apply, and one or more records to bind the values in. Here are some
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]731examples:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]732
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]733<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]734<pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]735<b>let</b> isTerminator = 1, isReturn = 1, isBarrier = 1, hasCtrlDep = 1 <b>in</b>
736 <b>def</b> RET : I&lt;0xC3, RawFrm, (outs), (ins), "ret", [(X86retflag 0)]&gt;;
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]737
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]738<b>let</b> isCall = 1 <b>in</b>
739 <i>// All calls clobber the non-callee saved registers...</i>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]740 <b>let</b> Defs = [EAX, ECX, EDX, FP0, FP1, FP2, FP3, FP4, FP5, FP6, ST0,
741 MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7,
742 XMM0, XMM1, XMM2, XMM3, XMM4, XMM5, XMM6, XMM7, EFLAGS] <b>in</b> {
Dan Gohman2ed27532008-10-14 17:00:38 +0000[diff] [blame]743 <b>def</b> CALLpcrel32 : Ii32&lt;0xE8, RawFrm, (outs), (ins i32imm:$dst,variable_ops),
744 "call\t${dst:call}", []&gt;;
745 <b>def</b> CALL32r : I&lt;0xFF, MRM2r, (outs), (ins GR32:$dst, variable_ops),
746 "call\t{*}$dst", [(X86call GR32:$dst)]&gt;;
747 <b>def</b> CALL32m : I&lt;0xFF, MRM2m, (outs), (ins i32mem:$dst, variable_ops),
748 "call\t{*}$dst", []&gt;;
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]749 }
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]750</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]751</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]752
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]753<p>File-scope "let" expressions are often useful when a couple of definitions
754need to be added to several records, and the records do not otherwise need to be
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]755opened, as in the case with the <tt>CALL*</tt> instructions above.</p>
756
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]757</div>
758
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]759<!-- *********************************************************************** -->
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]760<div class="doc_section"><a name="codegen">Code Generator backend info</a></div>
761<!-- *********************************************************************** -->
762
763<p>Expressions used by code generator to describe instructions and isel
764patterns:</p>
765
766<div class="doc_text">
767
768<dt><tt>(implicit a)</tt></dt>
769 <dd>an implicitly defined physical register. This tells the dag instruction
770 selection emitter the input pattern's extra definitions matches implicit
771 physical register definitions.</dd>
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]772
773</div>
774
775<!-- *********************************************************************** -->
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]776<div class="doc_section"><a name="backends">TableGen backends</a></div>
777<!-- *********************************************************************** -->
778
779<div class="doc_text">
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]780
781<p>TODO: How they work, how to write one. This section should not contain
782details about any particular backend, except maybe -print-enums as an example.
783This should highlight the APIs in <tt>TableGen/Record.h</tt>.</p>
784
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]785</div>
786
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]787<!-- *********************************************************************** -->
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]788
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]789<hr>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]790<address>
791 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]792 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]793 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]794 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]795
796 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]797 <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]798 Last modified: $Date$
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]799</address>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]800
801</body>
802</html>