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gerrit-public.fairphone.software / platform / external / llvm / dc5287c7388d0d57b139eafe7cf451bca9e47718 / . / docs / TableGenFundamentals.html
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5 <title>TableGen Fundamentals</title>
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7</head>
8<body>
9
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]10<h1>TableGen Fundamentals</h1>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]11
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]12<div>
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<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]53<h2><a name="introduction">Introduction</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]54<!-- *********************************************************************** -->
55
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]56<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]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<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]76<h3><a name="concepts">Basic concepts</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]77
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]78<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]79
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]80<p>TableGen files consist of two key parts: 'classes' and 'definitions', both
81of which are considered 'records'.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]82
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]83<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]84superclasses. The list of values is the main data that TableGen builds for each
85record; it is this that holds the domain specific information for the
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]86application. The interpretation of this data is left to a specific <a
87href="#backends">TableGen backend</a>, but the structure and format rules are
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]88taken care of and are fixed by TableGen.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]89
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]90<p><b>TableGen definitions</b> are the concrete form of 'records'. These
91generally do not have any undefined values, and are marked with the
92'<tt>def</tt>' keyword.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]93
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]94<p><b>TableGen classes</b> are abstract records that are used to build and
95describe other records. These 'classes' allow the end-user to build
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]96abstractions for either the domain they are targeting (such as "Register",
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]97"RegisterClass", and "Instruction" in the LLVM code generator) or for the
98implementor to help factor out common properties of records (such as "FPInst",
99which is used to represent floating point instructions in the X86 backend).
100TableGen keeps track of all of the classes that are used to build up a
101definition, so the backend can find all definitions of a particular class, such
102as "Instruction".</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]103
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]104<p><b>TableGen multiclasses</b> are groups of abstract records that are
David Greenede444af2009-04-22 16:42:54 +0000[diff] [blame]105instantiated all at once. Each instantiation can result in multiple
106TableGen definitions. If a multiclass inherits from another multiclass,
107the definitions in the sub-multiclass become part of the current
108multiclass, as if they were declared in the current multiclass.</p>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]109
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]110</div>
111
112<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]113<h3><a name="example">An example record</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]114
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]115<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]116
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]117<p>With no other arguments, TableGen parses the specified file and prints out
118all of the classes, then all of the definitions. This is a good way to see what
119the various definitions expand to fully. Running this on the <tt>X86.td</tt>
120file prints this (at the time of this writing):</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]121
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]122<div class="doc_code">
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]123<pre>
124...
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]125<b>def</b> ADD32rr { <i>// Instruction X86Inst I</i>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]126 <b>string</b> Namespace = "X86";
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]127 <b>dag</b> OutOperandList = (outs GR32:$dst);
128 <b>dag</b> InOperandList = (ins GR32:$src1, GR32:$src2);
129 <b>string</b> AsmString = "add{l}\t{$src2, $dst|$dst, $src2}";
130 <b>list</b>&lt;dag&gt; Pattern = [(set GR32:$dst, (add GR32:$src1, GR32:$src2))];
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]131 <b>list</b>&lt;Register&gt; Uses = [];
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]132 <b>list</b>&lt;Register&gt; Defs = [EFLAGS];
133 <b>list</b>&lt;Predicate&gt; Predicates = [];
134 <b>int</b> CodeSize = 3;
135 <b>int</b> AddedComplexity = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]136 <b>bit</b> isReturn = 0;
137 <b>bit</b> isBranch = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]138 <b>bit</b> isIndirectBranch = 0;
139 <b>bit</b> isBarrier = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]140 <b>bit</b> isCall = 0;
Dan Gohman15511cf2008-12-03 18:15:48 +0000[diff] [blame]141 <b>bit</b> canFoldAsLoad = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]142 <b>bit</b> mayLoad = 0;
143 <b>bit</b> mayStore = 0;
144 <b>bit</b> isImplicitDef = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]145 <b>bit</b> isConvertibleToThreeAddress = 1;
146 <b>bit</b> isCommutable = 1;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]147 <b>bit</b> isTerminator = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]148 <b>bit</b> isReMaterializable = 0;
149 <b>bit</b> isPredicable = 0;
150 <b>bit</b> hasDelaySlot = 0;
Dan Gohman533297b2009-10-29 18:10:34 +0000[diff] [blame]151 <b>bit</b> usesCustomInserter = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]152 <b>bit</b> hasCtrlDep = 0;
153 <b>bit</b> isNotDuplicable = 0;
154 <b>bit</b> hasSideEffects = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]155 <b>bit</b> neverHasSideEffects = 0;
156 InstrItinClass Itinerary = NoItinerary;
157 <b>string</b> Constraints = "";
158 <b>string</b> DisableEncoding = "";
159 <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]160 Format Form = MRMDestReg;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]161 <b>bits</b>&lt;6&gt; FormBits = { 0, 0, 0, 0, 1, 1 };
162 ImmType ImmT = NoImm;
163 <b>bits</b>&lt;3&gt; ImmTypeBits = { 0, 0, 0 };
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]164 <b>bit</b> hasOpSizePrefix = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]165 <b>bit</b> hasAdSizePrefix = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]166 <b>bits</b>&lt;4&gt; Prefix = { 0, 0, 0, 0 };
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]167 <b>bit</b> hasREX_WPrefix = 0;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]168 FPFormat FPForm = ?;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]169 <b>bits</b>&lt;3&gt; FPFormBits = { 0, 0, 0 };
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]170}
171...
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]172</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]173</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]174
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]175<p>This definition corresponds to a 32-bit register-register add instruction in
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]176the X86. The string after the '<tt>def</tt>' string indicates the name of the
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]177record&mdash;"<tt>ADD32rr</tt>" in this case&mdash;and the comment at the end of
178the line indicates the superclasses of the definition. The body of the record
179contains all of the data that TableGen assembled for the record, indicating that
180the instruction is part of the "X86" namespace, the pattern indicating how the
181the instruction should be emitted into the assembly file, that it is a
182two-address instruction, has a particular encoding, etc. The contents and
183semantics of the information in the record is specific to the needs of the X86
184backend, and is only shown as an example.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]185
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]186<p>As you can see, a lot of information is needed for every instruction
187supported by the code generator, and specifying it all manually would be
Dan Gohman8ff4b432010-02-26 02:15:17 +0000[diff] [blame]188unmaintainable, prone to bugs, and tiring to do in the first place. Because we
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]189are using TableGen, all of the information was derived from the following
190definition:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]191
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]192<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]193<pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]194let Defs = [EFLAGS],
195 isCommutable = 1, <i>// X = ADD Y,Z --&gt; X = ADD Z,Y</i>
196 isConvertibleToThreeAddress = 1 <b>in</b> <i>// Can transform into LEA.</i>
197def ADD32rr : I&lt;0x01, MRMDestReg, (outs GR32:$dst),
198 (ins GR32:$src1, GR32:$src2),
199 "add{l}\t{$src2, $dst|$dst, $src2}",
200 [(set GR32:$dst, (add GR32:$src1, GR32:$src2))]&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]201</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]202</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]203
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]204<p>This definition makes use of the custom class <tt>I</tt> (extended from the
205custom class <tt>X86Inst</tt>), which is defined in the X86-specific TableGen
206file, to factor out the common features that instructions of its class share. A
207key feature of TableGen is that it allows the end-user to define the
208abstractions they prefer to use when describing their information.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]209
David Greenedc5287c2011-10-19 13:04:56 +0000[diff] [blame^]210<p>Each def record has a special entry called "NAME." This is the
211name of the def ("ADD32rr" above). In the general case def names can
212be formed from various kinds of string processing expressions and NAME
213resolves to the final value obtained after resolving all of those
214expressions. The user may refer to NAME anywhere she desires to use
215the ultimate name of the def. NAME should not be defined anywhere
216else in user code to avoid conflict problems.</p>
217
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]218</div>
219
220<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]221<h3><a name="running">Running TableGen</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]222
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]223<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]224
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]225<p>TableGen runs just like any other LLVM tool. The first (optional) argument
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]226specifies the file to read. If a filename is not specified, <tt>tblgen</tt>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]227reads from standard input.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]228
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]229<p>To be useful, one of the <a href="#backends">TableGen backends</a> must be
230used. These backends are selectable on the command line (type '<tt>tblgen
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]231-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]232that subclass a particular type (which can be useful for building up an enum
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]233list of these records), use the <tt>-print-enums</tt> option:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]234
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]235<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]236<pre>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]237$ tblgen X86.td -print-enums -class=Register
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]238AH, AL, AX, BH, BL, BP, BPL, BX, CH, CL, CX, DH, DI, DIL, DL, DX, EAX, EBP, EBX,
239ECX, EDI, EDX, EFLAGS, EIP, ESI, ESP, FP0, FP1, FP2, FP3, FP4, FP5, FP6, IP,
240MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7, R10, R10B, R10D, R10W, R11, R11B, R11D,
241R11W, R12, R12B, R12D, R12W, R13, R13B, R13D, R13W, R14, R14B, R14D, R14W, R15,
242R15B, R15D, R15W, R8, R8B, R8D, R8W, R9, R9B, R9D, R9W, RAX, RBP, RBX, RCX, RDI,
243RDX, RIP, RSI, RSP, SI, SIL, SP, SPL, ST0, ST1, ST2, ST3, ST4, ST5, ST6, ST7,
244XMM0, XMM1, XMM10, XMM11, XMM12, XMM13, XMM14, XMM15, XMM2, XMM3, XMM4, XMM5,
245XMM6, XMM7, XMM8, XMM9,
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]246
247$ tblgen X86.td -print-enums -class=Instruction
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]248ABS_F, ABS_Fp32, ABS_Fp64, ABS_Fp80, ADC32mi, ADC32mi8, ADC32mr, ADC32ri,
249ADC32ri8, ADC32rm, ADC32rr, ADC64mi32, ADC64mi8, ADC64mr, ADC64ri32, ADC64ri8,
250ADC64rm, ADC64rr, ADD16mi, ADD16mi8, ADD16mr, ADD16ri, ADD16ri8, ADD16rm,
251ADD16rr, ADD32mi, ADD32mi8, ADD32mr, ADD32ri, ADD32ri8, ADD32rm, ADD32rr,
252ADD64mi32, ADD64mi8, ADD64mr, ADD64ri32, ...
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]253</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]254</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]255
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]256<p>The default backend prints out all of the records, as described <a
257href="#example">above</a>.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]258
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]259<p>If you plan to use TableGen, you will most likely have to <a
260href="#backends">write a backend</a> that extracts the information specific to
261what you need and formats it in the appropriate way.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]262
263</div>
264
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]265</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]266
267<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]268<h2><a name="syntax">TableGen syntax</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]269<!-- *********************************************************************** -->
270
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]271<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]272
273<p>TableGen doesn't care about the meaning of data (that is up to the backend to
274define), but it does care about syntax, and it enforces a simple type system.
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]275This section describes the syntax and the constructs allowed in a TableGen file.
276</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]277
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]278<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]279<h3><a name="primitives">TableGen primitives</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]280
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]281<div>
282
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]283<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]284<h4><a name="comments">TableGen comments</a></h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]285
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]286<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]287
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]288<p>TableGen supports BCPL style "<tt>//</tt>" comments, which run to the end of
289the line, and it also supports <b>nestable</b> "<tt>/* */</tt>" comments.</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]290
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]291</div>
292
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]293<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]294<h4>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]295 <a name="types">The TableGen type system</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]296</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]297
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]298<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]299
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]300<p>TableGen files are strongly typed, in a simple (but complete) type-system.
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]301These types are used to perform automatic conversions, check for errors, and to
302help interface designers constrain the input that they allow. Every <a
303href="#valuedef">value definition</a> is required to have an associated type.
304</p>
305
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]306<p>TableGen supports a mixture of very low-level types (such as <tt>bit</tt>)
307and very high-level types (such as <tt>dag</tt>). This flexibility is what
308allows it to describe a wide range of information conveniently and compactly.
309The TableGen types are:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]310
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]311<dl>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]312<dt><tt><b>bit</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]313 <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]314
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]315<dt><tt><b>int</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]316 <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]317
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]318<dt><tt><b>string</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]319 <dd>The 'string' type represents an ordered sequence of characters of
320 arbitrary length.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]321
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]322<dt><tt><b>bits</b>&lt;n&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]323 <dd>A 'bits' type is an arbitrary, but fixed, size integer that is broken up
324 into individual bits. This type is useful because it can handle some bits
325 being defined while others are undefined.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]326
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]327<dt><tt><b>list</b>&lt;ty&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]328 <dd>This type represents a list whose elements are some other type. The
329 contained type is arbitrary: it can even be another list type.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]330
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]331<dt>Class type</dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]332 <dd>Specifying a class name in a type context means that the defined value
333 must be a subclass of the specified class. This is useful in conjunction with
334 the <b><tt>list</tt></b> type, for example, to constrain the elements of the
335 list to a common base class (e.g., a <tt><b>list</b>&lt;Register&gt;</tt> can
336 only contain definitions derived from the "<tt>Register</tt>" class).</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]337
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]338<dt><tt><b>dag</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]339 <dd>This type represents a nestable directed graph of elements.</dd>
340
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]341<dt><tt><b>code</b></tt></dt>
Chris Lattnerca73cea2010-04-22 16:45:27 +0000[diff] [blame]342 <dd>This represents a big hunk of text. This is lexically distinct from
343 string values because it doesn't require escapeing double quotes and other
344 common characters that occur in code.</dd>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]345</dl>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]346
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]347<p>To date, these types have been sufficient for describing things that
348TableGen has been used for, but it is straight-forward to extend this list if
349needed.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]350
351</div>
352
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]353<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]354<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]355 <a name="values">TableGen values and expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]356</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]357
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]358<div>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]359
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]360<p>TableGen allows for a pretty reasonable number of different expression forms
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]361when building up values. These forms allow the TableGen file to be written in a
362natural syntax and flavor for the application. The current expression forms
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]363supported include:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]364
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]365<dl>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]366<dt><tt>?</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]367 <dd>uninitialized field</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]368<dt><tt>0b1001011</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]369 <dd>binary integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]370<dt><tt>07654321</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]371 <dd>octal integer value (indicated by a leading 0)</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]372<dt><tt>7</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]373 <dd>decimal integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]374<dt><tt>0x7F</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]375 <dd>hexadecimal integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]376<dt><tt>"foo"</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]377 <dd>string value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]378<dt><tt>[{ ... }]</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]379 <dd>code fragment</dd>
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]380<dt><tt>[ X, Y, Z ]&lt;type&gt;</tt></dt>
381 <dd>list value. &lt;type&gt; is the type of the list
David Greeneccbfb8d2009-06-08 22:38:07 +0000[diff] [blame]382element and is usually optional. In rare cases,
383TableGen is unable to deduce the element type in
384which case the user must specify it explicitly.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]385<dt><tt>{ a, b, c }</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]386 <dd>initializer for a "bits&lt;3&gt;" value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]387<dt><tt>value</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]388 <dd>value reference</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]389<dt><tt>value{17}</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]390 <dd>access to one bit of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]391<dt><tt>value{15-17}</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]392 <dd>access to multiple bits of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]393<dt><tt>DEF</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]394 <dd>reference to a record definition</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]395<dt><tt>CLASS&lt;val list&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]396 <dd>reference to a new anonymous definition of CLASS with the specified
397 template arguments.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]398<dt><tt>X.Y</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]399 <dd>reference to the subfield of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]400<dt><tt>list[4-7,17,2-3]</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]401 <dd>A slice of the 'list' list, including elements 4,5,6,7,17,2, and 3 from
402 it. Elements may be included multiple times.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]403<dt><tt>(DEF a, b)</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]404 <dd>a dag value. The first element is required to be a record definition, the
405 remaining elements in the list may be arbitrary other values, including nested
406 `<tt>dag</tt>' values.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]407<dt><tt>!strconcat(a, b)</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]408 <dd>A string value that is the result of concatenating the 'a' and 'b'
409 strings.</dd>
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]410<dt><tt>!cast&lt;type&gt;(a)</tt></dt>
David Greenee6c27de2009-05-14 21:22:49 +0000[diff] [blame]411 <dd>A symbol of type <em>type</em> obtained by looking up the string 'a' in
412the symbol table. If the type of 'a' does not match <em>type</em>, TableGen
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]413aborts 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]414be an object defined by a 'def' construct.</dd>
David Greene4afc5092009-05-14 21:54:42 +0000[diff] [blame]415<dt><tt>!subst(a, b, c)</tt></dt>
416 <dd>If 'a' and 'b' are of string type or are symbol references, substitute
417'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]418<dt><tt>!foreach(a, b, c)</tt></dt>
419 <dd>For each member 'b' of dag or list 'a' apply operator 'c.' 'b' is a
420dummy variable that should be declared as a member variable of an instantiated
421class. This operation is analogous to $(foreach) in GNU make.</dd>
David Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]422<dt><tt>!head(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]423 <dd>The first element of list 'a.'</dd>
David Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]424<dt><tt>!tail(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]425 <dd>The 2nd-N elements of list 'a.'</dd>
David Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]426<dt><tt>!empty(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]427 <dd>An integer {0,1} indicating whether list 'a' is empty.</dd>
David Greene9bea7c82009-05-14 23:26:46 +0000[diff] [blame]428<dt><tt>!if(a,b,c)</tt></dt>
Bruno Cardoso Lopeseba8f182010-06-17 00:31:36 +0000[diff] [blame]429 <dd>'b' if the result of 'int' or 'bit' operator 'a' is nonzero,
430 'c' otherwise.</dd>
David Greene6786d5e2010-01-05 19:11:42 +0000[diff] [blame]431<dt><tt>!eq(a,b)</tt></dt>
Chris Lattner150d20e2010-10-31 19:22:57 +0000[diff] [blame]432 <dd>'bit 1' if string a is equal to string b, 0 otherwise. This
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]433 only operates on string, int and bit objects. Use !cast&lt;string&gt; to
Bruno Cardoso Lopese87de412010-06-16 23:24:12 +0000[diff] [blame]434 compare other types of objects.</dd>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]435</dl>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]436
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]437<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]438for different types. These rules allow you to assign a value like "<tt>7</tt>"
439to a "<tt>bits&lt;4&gt;</tt>" value, for example.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]440
441</div>
442
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]443</div>
444
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]445<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]446<h3>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]447 <a name="classesdefs">Classes and definitions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]448</h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]449
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]450<div>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]451
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]452<p>As mentioned in the <a href="#concepts">intro</a>, classes and definitions
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]453(collectively known as 'records') in TableGen are the main high-level unit of
454information that TableGen collects. Records are defined with a <tt>def</tt> or
455<tt>class</tt> keyword, the record name, and an optional list of "<a
Misha Brukman179bf4b2004-06-03 23:42:24 +0000[diff] [blame]456href="#templateargs">template arguments</a>". If the record has superclasses,
Jeff Cohen0b81cda2005-10-24 16:54:55 +0000[diff] [blame]457they are specified as a comma separated list that starts with a colon character
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]458("<tt>:</tt>"). If <a href="#valuedef">value definitions</a> or <a
459href="#recordlet">let expressions</a> are needed for the class, they are
460enclosed in curly braces ("<tt>{}</tt>"); otherwise, the record ends with a
461semicolon.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]462
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]463<p>Here is a simple TableGen file:</p>
464
465<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]466<pre>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]467<b>class</b> C { <b>bit</b> V = 1; }
468<b>def</b> X : C;
469<b>def</b> Y : C {
470 <b>string</b> Greeting = "hello";
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]471}
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]472</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]473</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]474
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]475<p>This example defines two definitions, <tt>X</tt> and <tt>Y</tt>, both of
476which derive from the <tt>C</tt> class. Because of this, they both get the
477<tt>V</tt> bit value. The <tt>Y</tt> definition also gets the Greeting member
478as well.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]479
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]480<p>In general, classes are useful for collecting together the commonality
481between a group of records and isolating it in a single place. Also, classes
482permit the specification of default values for their subclasses, allowing the
483subclasses to override them as they wish.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]484
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]485<!---------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]486<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]487 <a name="valuedef">Value definitions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]488</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]489
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]490<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]491
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]492<p>Value definitions define named entries in records. A value must be defined
John Criswellaa55c8c2004-02-12 18:11:53 +0000[diff] [blame]493before it can be referred to as the operand for another value definition or
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]494before the value is reset with a <a href="#recordlet">let expression</a>. A
495value is defined by specifying a <a href="#types">TableGen type</a> and a name.
496If an initial value is available, it may be specified after the type with an
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]497equal sign. Value definitions require terminating semicolons.</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]498
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]499</div>
500
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]501<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]502<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]503 <a name="recordlet">'let' expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]504</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]505
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]506<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]507
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]508<p>A record-level let expression is used to change the value of a value
509definition in a record. This is primarily useful when a superclass defines a
510value that a derived class or definition wants to override. Let expressions
511consist of the '<tt>let</tt>' keyword followed by a value name, an equal sign
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]512("<tt>=</tt>"), and a new value. For example, a new class could be added to the
513example above, redefining the <tt>V</tt> field for all of its subclasses:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]514
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]515<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]516<pre>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]517<b>class</b> D : C { let V = 0; }
518<b>def</b> Z : D;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]519</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]520</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]521
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]522<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]523value, despite the fact that it derives (indirectly) from the <tt>C</tt> class,
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]524because the <tt>D</tt> class overrode its value.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]525
526</div>
527
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]528<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]529<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]530 <a name="templateargs">Class template arguments</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]531</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]532
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]533<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]534
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]535<p>TableGen permits the definition of parameterized classes as well as normal
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]536concrete classes. Parameterized TableGen classes specify a list of variable
537bindings (which may optionally have defaults) that are bound when used. Here is
538a simple example:</p>
539
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]540<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]541<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]542<b>class</b> FPFormat&lt;<b>bits</b>&lt;3&gt; val&gt; {
543 <b>bits</b>&lt;3&gt; Value = val;
544}
545<b>def</b> NotFP : FPFormat&lt;0&gt;;
546<b>def</b> ZeroArgFP : FPFormat&lt;1&gt;;
547<b>def</b> OneArgFP : FPFormat&lt;2&gt;;
548<b>def</b> OneArgFPRW : FPFormat&lt;3&gt;;
549<b>def</b> TwoArgFP : FPFormat&lt;4&gt;;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]550<b>def</b> CompareFP : FPFormat&lt;5&gt;;
551<b>def</b> CondMovFP : FPFormat&lt;6&gt;;
552<b>def</b> SpecialFP : FPFormat&lt;7&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]553</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]554</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]555
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]556<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]557a list of "enumeration values", each with a "<tt>Value</tt>" field set to the
558specified integer.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]559
560<p>The more esoteric forms of <a href="#values">TableGen expressions</a> are
561useful in conjunction with template arguments. As an example:</p>
562
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]563<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]564<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]565<b>class</b> ModRefVal&lt;<b>bits</b>&lt;2&gt; val&gt; {
566 <b>bits</b>&lt;2&gt; Value = val;
567}
568
569<b>def</b> None : ModRefVal&lt;0&gt;;
570<b>def</b> Mod : ModRefVal&lt;1&gt;;
571<b>def</b> Ref : ModRefVal&lt;2&gt;;
572<b>def</b> ModRef : ModRefVal&lt;3&gt;;
573
574<b>class</b> Value&lt;ModRefVal MR&gt; {
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]575 <i>// Decode some information into a more convenient format, while providing
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]576 // a nice interface to the user of the "Value" class.</i>
577 <b>bit</b> isMod = MR.Value{0};
578 <b>bit</b> isRef = MR.Value{1};
579
580 <i>// other stuff...</i>
581}
582
583<i>// Example uses</i>
584<b>def</b> bork : Value&lt;Mod&gt;;
585<b>def</b> zork : Value&lt;Ref&gt;;
586<b>def</b> hork : Value&lt;ModRef&gt;;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]587</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]588</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]589
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]590<p>This is obviously a contrived example, but it shows how template arguments
591can 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]592actual internal data representation expected by the class. In this case,
593running <tt>tblgen</tt> on the example prints the following definitions:</p>
594
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]595<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]596<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]597<b>def</b> bork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]598 <b>bit</b> isMod = 1;
599 <b>bit</b> isRef = 0;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]600}
601<b>def</b> hork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]602 <b>bit</b> isMod = 1;
603 <b>bit</b> isRef = 1;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]604}
605<b>def</b> zork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]606 <b>bit</b> isMod = 0;
607 <b>bit</b> isRef = 1;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]608}
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]609</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]610</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]611
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]612<p> This shows that TableGen was able to dig into the argument and extract a
613piece of information that was requested by the designer of the "Value" class.
614For more realistic examples, please see existing users of TableGen, such as the
615X86 backend.</p>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]616
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]617</div>
618
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]619<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]620<h4>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]621 <a name="multiclass">Multiclass definitions and instances</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]622</h4>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]623
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]624<div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]625
626<p>
627While classes with template arguments are a good way to factor commonality
628between two instances of a definition, multiclasses allow a convenient notation
629for defining multiple definitions at once (instances of implicitly constructed
630classes). For example, consider an 3-address instruction set whose instructions
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]631come in two forms: "<tt>reg = reg op reg</tt>" and "<tt>reg = reg op imm</tt>"
632(e.g. SPARC). In this case, you'd like to specify in one place that this
633commonality exists, then in a separate place indicate what all the ops are.
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]634</p>
635
636<p>
637Here is an example TableGen fragment that shows this idea:
638</p>
639
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]640<div class="doc_code">
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]641<pre>
642<b>def</b> ops;
643<b>def</b> GPR;
644<b>def</b> Imm;
645<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
646
647<b>multiclass</b> ri_inst&lt;<b>int</b> opc, <b>string</b> asmstr&gt; {
648 def _rr : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
649 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
650 def _ri : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
651 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
652}
653
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]654<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]655<b>defm</b> ADD : ri_inst&lt;0b111, "add"&gt;;
656<b>defm</b> SUB : ri_inst&lt;0b101, "sub"&gt;;
657<b>defm</b> MUL : ri_inst&lt;0b100, "mul"&gt;;
658...
659</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]660</div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]661
Chris Lattnere7173e12006-09-01 22:01:36 +0000[diff] [blame]662<p>The name of the resultant definitions has the multidef fragment names
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]663 appended to them, so this defines <tt>ADD_rr</tt>, <tt>ADD_ri</tt>,
David Greene56546132009-04-22 22:17:51 +0000[diff] [blame]664 <tt>SUB_rr</tt>, etc. A defm may inherit from multiple multiclasses,
665 instantiating definitions from each multiclass. Using a multiclass
666 this way is exactly equivalent to instantiating the classes multiple
667 times yourself, e.g. by writing:</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]668
669<div class="doc_code">
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]670<pre>
671<b>def</b> ops;
672<b>def</b> GPR;
673<b>def</b> Imm;
674<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
675
676<b>class</b> rrinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
677 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
678 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
679
680<b>class</b> riinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
681 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
682 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
683
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]684<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]685<b>def</b> ADD_rr : rrinst&lt;0b111, "add"&gt;;
686<b>def</b> ADD_ri : riinst&lt;0b111, "add"&gt;;
687<b>def</b> SUB_rr : rrinst&lt;0b101, "sub"&gt;;
688<b>def</b> SUB_ri : riinst&lt;0b101, "sub"&gt;;
689<b>def</b> MUL_rr : rrinst&lt;0b100, "mul"&gt;;
690<b>def</b> MUL_ri : riinst&lt;0b100, "mul"&gt;;
691...
692</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]693</div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]694
Bruno Cardoso Lopes270562b2010-06-05 02:11:52 +0000[diff] [blame]695<p>
696A defm can also be used inside a multiclass providing several levels of
697multiclass instanciations.
698</p>
699
700<div class="doc_code">
701<pre>
702<b>class</b> Instruction&lt;bits&lt;4&gt; opc, string Name&gt; {
703 bits&lt;4&gt; opcode = opc;
704 string name = Name;
705}
706
707<b>multiclass</b> basic_r&lt;bits&lt;4&gt; opc&gt; {
708 <b>def</b> rr : Instruction&lt;opc, "rr"&gt;;
709 <b>def</b> rm : Instruction&lt;opc, "rm"&gt;;
710}
711
712<b>multiclass</b> basic_s&lt;bits&lt;4&gt; opc&gt; {
713 <b>defm</b> SS : basic_r&lt;opc&gt;;
714 <b>defm</b> SD : basic_r&lt;opc&gt;;
715 <b>def</b> X : Instruction&lt;opc, "x"&gt;;
716}
717
718<b>multiclass</b> basic_p&lt;bits&lt;4&gt; opc&gt; {
719 <b>defm</b> PS : basic_r&lt;opc&gt;;
720 <b>defm</b> PD : basic_r&lt;opc&gt;;
721 <b>def</b> Y : Instruction&lt;opc, "y"&gt;;
722}
723
724<b>defm</b> ADD : basic_s&lt;0xf&gt;, basic_p&lt;0xf&gt;;
725...
726
727<i>// Results</i>
728<b>def</b> ADDPDrm { ...
729<b>def</b> ADDPDrr { ...
730<b>def</b> ADDPSrm { ...
731<b>def</b> ADDPSrr { ...
732<b>def</b> ADDSDrm { ...
733<b>def</b> ADDSDrr { ...
734<b>def</b> ADDY { ...
735<b>def</b> ADDX { ...
736</pre>
737</div>
738
Bruno Cardoso Lopes6e0a99a2010-06-18 19:53:41 +0000[diff] [blame]739<p>
740defm declarations can inherit from classes too, the
741rule to follow is that the class list must start after the
742last multiclass, and there must be at least one multiclass
743before them.
744</p>
745
746<div class="doc_code">
747<pre>
748<b>class</b> XD { bits&lt;4&gt; Prefix = 11; }
749<b>class</b> XS { bits&lt;4&gt; Prefix = 12; }
750
751<b>class</b> I&lt;bits<4&gt; op> {
752 bits&lt;4&gt; opcode = op;
753}
754
755<b>multiclass</b> R {
756 <b>def</b> rr : I&lt;4&gt;;
757 <b>def</b> rm : I&lt;2&gt;;
758}
759
760<b>multiclass</b> Y {
761 <b>defm</b> SS : R, XD;
762 <b>defm</b> SD : R, XS;
763}
764
765<b>defm</b> Instr : Y;
766
767<i>// Results</i>
768<b>def</b> InstrSDrm {
769 bits&lt;4&gt; opcode = { 0, 0, 1, 0 };
770 bits&lt;4&gt; Prefix = { 1, 1, 0, 0 };
771}
772...
773<b>def</b> InstrSSrr {
774 bits&lt;4&gt; opcode = { 0, 1, 0, 0 };
775 bits&lt;4&gt; Prefix = { 1, 0, 1, 1 };
776}
777</pre>
778</div>
779
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]780</div>
781
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]782</div>
783
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]784<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]785<h3>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]786 <a name="filescope">File scope entities</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]787</h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]788
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]789<div>
790
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]791<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]792<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]793 <a name="include">File inclusion</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]794</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]795
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]796<div>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]797<p>TableGen supports the '<tt>include</tt>' token, which textually substitutes
798the specified file in place of the include directive. The filename should be
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]799specified as a double quoted string immediately after the '<tt>include</tt>'
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]800keyword. Example:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]801
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]802<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]803<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]804<b>include</b> "foo.td"
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]805</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]806</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]807
808</div>
809
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]810<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]811<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]812 <a name="globallet">'let' expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]813</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]814
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]815<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]816
817<p>"Let" expressions at file scope are similar to <a href="#recordlet">"let"
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]818expressions within a record</a>, except they can specify a value binding for
819multiple records at a time, and may be useful in certain other cases.
820File-scope let expressions are really just another way that TableGen allows the
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]821end-user to factor out commonality from the records.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]822
Jeff Cohen0b81cda2005-10-24 16:54:55 +0000[diff] [blame]823<p>File-scope "let" expressions take a comma-separated list of bindings to
Matthijs Kooijman94199da2008-10-20 08:45:34 +0000[diff] [blame]824apply, and one or more records to bind the values in. Here are some
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]825examples:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]826
Bill Wendling6171ab62010-12-08 02:46:25 +0000[diff] [blame]827<div class="doc_code">
828<pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]829<b>let</b> isTerminator = 1, isReturn = 1, isBarrier = 1, hasCtrlDep = 1 <b>in</b>
830 <b>def</b> RET : I&lt;0xC3, RawFrm, (outs), (ins), "ret", [(X86retflag 0)]&gt;;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]831
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]832<b>let</b> isCall = 1 <b>in</b>
833 <i>// All calls clobber the non-callee saved registers...</i>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]834 <b>let</b> Defs = [EAX, ECX, EDX, FP0, FP1, FP2, FP3, FP4, FP5, FP6, ST0,
835 MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7,
836 XMM0, XMM1, XMM2, XMM3, XMM4, XMM5, XMM6, XMM7, EFLAGS] <b>in</b> {
Dan Gohman364a39f2008-10-14 17:00:38 +0000[diff] [blame]837 <b>def</b> CALLpcrel32 : Ii32&lt;0xE8, RawFrm, (outs), (ins i32imm:$dst,variable_ops),
838 "call\t${dst:call}", []&gt;;
839 <b>def</b> CALL32r : I&lt;0xFF, MRM2r, (outs), (ins GR32:$dst, variable_ops),
840 "call\t{*}$dst", [(X86call GR32:$dst)]&gt;;
841 <b>def</b> CALL32m : I&lt;0xFF, MRM2m, (outs), (ins i32mem:$dst, variable_ops),
842 "call\t{*}$dst", []&gt;;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]843 }
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]844</pre>
Bill Wendling6171ab62010-12-08 02:46:25 +0000[diff] [blame]845</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]846
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]847<p>File-scope "let" expressions are often useful when a couple of definitions
848need 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]849opened, as in the case with the <tt>CALL*</tt> instructions above.</p>
850
Bruno Cardoso Lopesee65db32010-06-10 02:42:59 +0000[diff] [blame]851<p>It's also possible to use "let" expressions inside multiclasses, providing
852more ways to factor out commonality from the records, specially if using
853several levels of multiclass instanciations. This also avoids the need of using
854"let" expressions within subsequent records inside a multiclass.</p>
855
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]856<pre class="doc_code">
Bruno Cardoso Lopesee65db32010-06-10 02:42:59 +0000[diff] [blame]857<b>multiclass </b>basic_r&lt;bits&lt;4&gt; opc&gt; {
858 <b>let </b>Predicates = [HasSSE2] in {
859 <b>def </b>rr : Instruction&lt;opc, "rr"&gt;;
860 <b>def </b>rm : Instruction&lt;opc, "rm"&gt;;
861 }
862 <b>let </b>Predicates = [HasSSE3] in
863 <b>def </b>rx : Instruction&lt;opc, "rx"&gt;;
864}
865
866<b>multiclass </b>basic_ss&lt;bits&lt;4&gt; opc&gt; {
867 <b>let </b>IsDouble = 0 in
868 <b>defm </b>SS : basic_r&lt;opc&gt;;
869
870 <b>let </b>IsDouble = 1 in
871 <b>defm </b>SD : basic_r&lt;opc&gt;;
872}
873
874<b>defm </b>ADD : basic_ss&lt;0xf&gt;;
875</pre>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]876</div>
877
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]878</div>
879
880</div>
881
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]882<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]883<h2><a name="codegen">Code Generator backend info</a></h2>
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]884<!-- *********************************************************************** -->
885
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]886<div>
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]887
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]888<p>Expressions used by code generator to describe instructions and isel
889patterns:</p>
890
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]891<dl>
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]892<dt><tt>(implicit a)</tt></dt>
893 <dd>an implicitly defined physical register. This tells the dag instruction
894 selection emitter the input pattern's extra definitions matches implicit
895 physical register definitions.</dd>
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]896</dl>
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]897</div>
898
899<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]900<h2><a name="backends">TableGen backends</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]901<!-- *********************************************************************** -->
902
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]903<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]904
905<p>TODO: How they work, how to write one. This section should not contain
906details about any particular backend, except maybe -print-enums as an example.
907This should highlight the APIs in <tt>TableGen/Record.h</tt>.</p>
908
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]909</div>
910
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]911<!-- *********************************************************************** -->
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]912
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]913<hr>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]914<address>
915 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]919
920 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]921 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]922 Last modified: $Date$
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]923</address>
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925</body>
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