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7</head>
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9
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]10<h1>TableGen Fundamentals</h1>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]11
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]12<div>
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<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]53<h2><a name="introduction">Introduction</a></h2>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]54<!-- *********************************************************************** -->
55
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]56<div>
Chris Lattner149a2492004-02-06 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 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<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]76<h3><a name="concepts">Basic concepts</a></h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]77
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]78<div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]79
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]82
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]88taken care of and are fixed by TableGen.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]89
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]93
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]96abstractions for either the domain they are targeting (such as "Register",
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]103
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]104<p><b>TableGen multiclasses</b> are groups of abstract records that are
David Greene753ed8f2009-04-22 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 Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]109
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]110</div>
111
112<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]113<h3><a name="example">An example record</a></h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]114
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]115<div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]116
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]121
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]122<div class="doc_code">
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]123<pre>
124...
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]125<b>def</b> ADD32rr { <i>// Instruction X86Inst I</i>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]126 <b>string</b> Namespace = "X86";
Bill Wendling1a19af92008-02-12 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 Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]131 <b>list</b>&lt;Register&gt; Uses = [];
Bill Wendling1a19af92008-02-12 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 Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]136 <b>bit</b> isReturn = 0;
137 <b>bit</b> isBranch = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]138 <b>bit</b> isIndirectBranch = 0;
139 <b>bit</b> isBarrier = 0;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]140 <b>bit</b> isCall = 0;
Dan Gohman69cc2cb2008-12-03 18:15:48 +0000[diff] [blame]141 <b>bit</b> canFoldAsLoad = 0;
Bill Wendling1a19af92008-02-12 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]145 <b>bit</b> isConvertibleToThreeAddress = 1;
146 <b>bit</b> isCommutable = 1;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]147 <b>bit</b> isTerminator = 0;
Bill Wendling1a19af92008-02-12 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 Gohman453d64c2009-10-29 18:10:34 +0000[diff] [blame]151 <b>bit</b> usesCustomInserter = 0;
Bill Wendling1a19af92008-02-12 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 Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]160 Format Form = MRMDestReg;
Bill Wendling1a19af92008-02-12 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 Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]164 <b>bit</b> hasOpSizePrefix = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]165 <b>bit</b> hasAdSizePrefix = 0;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]166 <b>bits</b>&lt;4&gt; Prefix = { 0, 0, 0, 0 };
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]167 <b>bit</b> hasREX_WPrefix = 0;
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]168 FPFormat FPForm = ?;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]169 <b>bits</b>&lt;3&gt; FPFormBits = { 0, 0, 0 };
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]170}
171...
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]172</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]173</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]174
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]175<p>This definition corresponds to a 32-bit register-register add instruction in
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]176the X86. The string after the '<tt>def</tt>' string indicates the name of the
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]185
Misha Brukman692cec02004-05-12 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 Gohman5aa39192010-02-26 02:15:17 +0000[diff] [blame]188unmaintainable, prone to bugs, and tiring to do in the first place. Because we
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]189are using TableGen, all of the information was derived from the following
190definition:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]191
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]192<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]193<pre>
Bill Wendling1a19af92008-02-12 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]201</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]202</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]203
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]209
David Greenee7c3ea92011-10-19 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]218</div>
219
220<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]221<h3><a name="running">Running TableGen</a></h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]222
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]223<div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]224
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]225<p>TableGen runs just like any other LLVM tool. The first (optional) argument
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]226specifies the file to read. If a filename is not specified, <tt>tblgen</tt>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]227reads from standard input.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]228
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]231-help</tt>' for a list). For example, to get a list of all of the definitions
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]232that subclass a particular type (which can be useful for building up an enum
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]233list of these records), use the <tt>-print-enums</tt> option:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]234
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]235<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]236<pre>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]237$ tblgen X86.td -print-enums -class=Register
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]246
247$ tblgen X86.td -print-enums -class=Instruction
Bill Wendling1a19af92008-02-12 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]253</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]254</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]255
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]258
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]262
263</div>
264
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]265</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]266
267<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]268<h2><a name="syntax">TableGen syntax</a></h2>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]269<!-- *********************************************************************** -->
270
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]271<div>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]275This section describes the syntax and the constructs allowed in a TableGen file.
276</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]277
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]278<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]279<h3><a name="primitives">TableGen primitives</a></h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]280
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]281<div>
282
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]283<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]284<h4><a name="comments">TableGen comments</a></h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]285
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]286<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]287
Chris Lattner149a2492004-02-06 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]290
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]291</div>
292
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]293<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]294<h4>
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]295 <a name="types">The TableGen type system</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]296</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]297
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]298<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]299
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]300<p>TableGen files are strongly typed, in a simple (but complete) type-system.
Chris Lattner149a2492004-02-06 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 Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]310
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]311<dl>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]312<dt><tt><b>bit</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]313 <dd>A 'bit' is a boolean value that can hold either 0 or 1.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]314
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]315<dt><tt><b>int</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]316 <dd>The 'int' type represents a simple 32-bit integer value, such as 5.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]317
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]318<dt><tt><b>string</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]319 <dd>The 'string' type represents an ordered sequence of characters of
320 arbitrary length.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]321
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]322<dt><tt><b>bits</b>&lt;n&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]326
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]327<dt><tt><b>list</b>&lt;ty&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]330
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]331<dt>Class type</dt>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]337
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]338<dt><tt><b>dag</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]339 <dd>This type represents a nestable directed graph of elements.</dd>
340
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]341<dt><tt><b>code</b></tt></dt>
Chris Lattner28175bf2010-04-22 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]345</dl>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]346
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]350
351</div>
352
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]353<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]354<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]355 <a name="values">TableGen values and expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]356</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]357
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]358<div>
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]359
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]360<p>TableGen allows for a pretty reasonable number of different expression forms
Chris Lattner149a2492004-02-06 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]363supported include:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]364
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]365<dl>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]366<dt><tt>?</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]367 <dd>uninitialized field</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]368<dt><tt>0b1001011</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]369 <dd>binary integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]370<dt><tt>07654321</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]371 <dd>octal integer value (indicated by a leading 0)</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]372<dt><tt>7</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]373 <dd>decimal integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]374<dt><tt>0x7F</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]375 <dd>hexadecimal integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]376<dt><tt>"foo"</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]377 <dd>string value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]378<dt><tt>[{ ... }]</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]379 <dd>code fragment</dd>
Benjamin Kramereaccdd32009-08-05 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 Greene26433c22009-06-08 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 Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]385<dt><tt>{ a, b, c }</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]386 <dd>initializer for a "bits&lt;3&gt;" value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]387<dt><tt>value</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]388 <dd>value reference</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]389<dt><tt>value{17}</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]390 <dd>access to one bit of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]391<dt><tt>value{15-17}</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]392 <dd>access to multiple bits of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]393<dt><tt>DEF</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]394 <dd>reference to a record definition</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]395<dt><tt>CLASS&lt;val list&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]396 <dd>reference to a new anonymous definition of CLASS with the specified
397 template arguments.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]398<dt><tt>X.Y</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]399 <dd>reference to the subfield of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]400<dt><tt>list[4-7,17,2-3]</tt></dt>
Bill Wendling1a19af92008-02-12 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 Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]403<dt><tt>(DEF a, b)</tt></dt>
Bill Wendling1a19af92008-02-12 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 Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]407<dt><tt>!strconcat(a, b)</tt></dt>
Bill Wendling1a19af92008-02-12 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 Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]410<dt><tt>!cast&lt;type&gt;(a)</tt></dt>
David Greenee8f3b272009-05-14 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 Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]413aborts with an error. !cast&lt;string&gt; is a special case in that the argument must
David Greeneefa19612009-06-29 20:05:29 +0000[diff] [blame]414be an object defined by a 'def' construct.</dd>
David Greene98ed3c72009-05-14 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 Greenee917fff2009-05-14 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 Greene2f7cf7f2011-01-07 17:05:37 +0000[diff] [blame]422<dt><tt>!head(a)</tt></dt>
David Greened571b3c2009-05-14 22:38:31 +0000[diff] [blame]423 <dd>The first element of list 'a.'</dd>
David Greene2f7cf7f2011-01-07 17:05:37 +0000[diff] [blame]424<dt><tt>!tail(a)</tt></dt>
David Greened571b3c2009-05-14 22:38:31 +0000[diff] [blame]425 <dd>The 2nd-N elements of list 'a.'</dd>
David Greene2f7cf7f2011-01-07 17:05:37 +0000[diff] [blame]426<dt><tt>!empty(a)</tt></dt>
David Greened571b3c2009-05-14 22:38:31 +0000[diff] [blame]427 <dd>An integer {0,1} indicating whether list 'a' is empty.</dd>
David Greene3587eed2009-05-14 23:26:46 +0000[diff] [blame]428<dt><tt>!if(a,b,c)</tt></dt>
Bruno Cardoso Lopes4d1d7982010-06-17 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 Greene297bfe62010-01-05 19:11:42 +0000[diff] [blame]431<dt><tt>!eq(a,b)</tt></dt>
Chris Lattner7ff33462010-10-31 19:22:57 +0000[diff] [blame]432 <dd>'bit 1' if string a is equal to string b, 0 otherwise. This
Benjamin Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]433 only operates on string, int and bit objects. Use !cast&lt;string&gt; to
Bruno Cardoso Lopes77a4a562010-06-16 23:24:12 +0000[diff] [blame]434 compare other types of objects.</dd>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]435</dl>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]436
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]437<p>Note that all of the values have rules specifying how they convert to values
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]440
441</div>
442
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]443</div>
444
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]445<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]446<h3>
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]447 <a name="classesdefs">Classes and definitions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]448</h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]449
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]450<div>
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]451
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]452<p>As mentioned in the <a href="#concepts">intro</a>, classes and definitions
Chris Lattner149a2492004-02-06 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 Brukman31551592004-06-03 23:42:24 +0000[diff] [blame]456href="#templateargs">template arguments</a>". If the record has superclasses,
Jeff Cohendd24d7c2005-10-24 16:54:55 +0000[diff] [blame]457they are specified as a comma separated list that starts with a colon character
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]462
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]463<p>Here is a simple TableGen file:</p>
464
465<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]466<pre>
Chris Lattner1215e322004-02-06 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]471}
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]472</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]473</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]474
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]479
Misha Brukman692cec02004-05-12 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 Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]484
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]485<!---------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]486<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]487 <a name="valuedef">Value definitions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]488</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]489
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]490<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]491
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]492<p>Value definitions define named entries in records. A value must be defined
John Criswell407f6d42004-02-12 18:11:53 +0000[diff] [blame]493before it can be referred to as the operand for another value definition or
Chris Lattner149a2492004-02-06 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]497equal sign. Value definitions require terminating semicolons.</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]498
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]499</div>
500
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]501<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]502<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]503 <a name="recordlet">'let' expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]504</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]505
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]506<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]507
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]514
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]515<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]516<pre>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]517<b>class</b> D : C { let V = 0; }
518<b>def</b> Z : D;
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]519</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]520</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]521
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]523value, despite the fact that it derives (indirectly) from the <tt>C</tt> class,
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]524because the <tt>D</tt> class overrode its value.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]525
526</div>
527
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]528<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]529<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]530 <a name="templateargs">Class template arguments</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]531</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]532
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]533<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]534
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]535<p>TableGen permits the definition of parameterized classes as well as normal
Chris Lattner55927232004-02-06 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]540<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]541<pre>
Chris Lattner55927232004-02-06 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 Wendling1a19af92008-02-12 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]553</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]554</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]555
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]556<p>In this case, template arguments are used as a space efficient way to specify
Bill Wendling1a19af92008-02-12 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 Lattner55927232004-02-06 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]563<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]564<pre>
Chris Lattner55927232004-02-06 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]575 <i>// Decode some information into a more convenient format, while providing
Chris Lattner55927232004-02-06 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]587</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]588</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]589
Misha Brukman692cec02004-05-12 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 Lattner55927232004-02-06 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]595<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]596<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]597<b>def</b> bork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]598 <b>bit</b> isMod = 1;
599 <b>bit</b> isRef = 0;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]600}
601<b>def</b> hork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]602 <b>bit</b> isMod = 1;
603 <b>bit</b> isRef = 1;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]604}
605<b>def</b> zork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]606 <b>bit</b> isMod = 0;
607 <b>bit</b> isRef = 1;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]608}
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]609</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]610</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]611
Misha Brukman692cec02004-05-12 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 Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]616
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]617</div>
618
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]619<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]620<h4>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]621 <a name="multiclass">Multiclass definitions and instances</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]622</h4>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]623
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]624<div>
Chris Lattnerf01a85b2006-09-01 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 Wendling1a19af92008-02-12 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 Lattnerf01a85b2006-09-01 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]640<div class="doc_code">
Chris Lattnerf01a85b2006-09-01 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]654<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattnerf01a85b2006-09-01 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]660</div>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]661
Chris Lattner28368122006-09-01 22:01:36 +0000[diff] [blame]662<p>The name of the resultant definitions has the multidef fragment names
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]663 appended to them, so this defines <tt>ADD_rr</tt>, <tt>ADD_ri</tt>,
David Greenef00919a2009-04-22 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]668
669<div class="doc_code">
Chris Lattnerf01a85b2006-09-01 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]684<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattnerf01a85b2006-09-01 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]693</div>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]694
Bruno Cardoso Lopesc4f61482010-06-05 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 Lopes23f83212010-06-18 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 Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]780</div>
781
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]782</div>
783
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]784<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]785<h3>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]786 <a name="filescope">File scope entities</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]787</h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]788
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]789<div>
790
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]791<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]792<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]793 <a name="include">File inclusion</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]794</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]795
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]796<div>
Misha Brukman692cec02004-05-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]799specified as a double quoted string immediately after the '<tt>include</tt>'
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]800keyword. Example:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]801
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]802<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]803<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]804<b>include</b> "foo.td"
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]805</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]806</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]807
808</div>
809
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]810<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]811<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]812 <a name="globallet">'let' expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]813</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]814
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]815<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]816
817<p>"Let" expressions at file scope are similar to <a href="#recordlet">"let"
Chris Lattner149a2492004-02-06 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]821end-user to factor out commonality from the records.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]822
Jeff Cohendd24d7c2005-10-24 16:54:55 +0000[diff] [blame]823<p>File-scope "let" expressions take a comma-separated list of bindings to
Matthijs Kooijman3abb3082008-10-20 08:45:34 +0000[diff] [blame]824apply, and one or more records to bind the values in. Here are some
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]825examples:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]826
Bill Wendling7a05f002010-12-08 02:46:25 +0000[diff] [blame]827<div class="doc_code">
828<pre>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]831
Chris Lattner1215e322004-02-06 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 Wendling1a19af92008-02-12 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 Gohman2ed27532008-10-14 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]843 }
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]844</pre>
Bill Wendling7a05f002010-12-08 02:46:25 +0000[diff] [blame]845</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]846
Misha Brukman692cec02004-05-12 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 Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]849opened, as in the case with the <tt>CALL*</tt> instructions above.</p>
850
Bruno Cardoso Lopes5f2adcc2010-06-10 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 Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]856<pre class="doc_code">
Bruno Cardoso Lopes5f2adcc2010-06-10 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]876</div>
877
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]878</div>
879
880</div>
881
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]882<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]883<h2><a name="codegen">Code Generator backend info</a></h2>
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]884<!-- *********************************************************************** -->
885
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]886<div>
Benjamin Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]887
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]888<p>Expressions used by code generator to describe instructions and isel
889patterns:</p>
890
Benjamin Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]891<dl>
Evan Chengef716b02009-10-05 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 Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]896</dl>
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]897</div>
898
899<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]900<h2><a name="backends">TableGen backends</a></h2>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]901<!-- *********************************************************************** -->
902
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]903<div>
Bill Wendling1a19af92008-02-12 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 Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]909</div>
910
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]911<!-- *********************************************************************** -->
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]912
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]913<hr>
Misha Brukman692cec02004-05-12 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 Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]919
920 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]921 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]922 Last modified: $Date$
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]923</address>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]924
925</body>
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