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10
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]11<h1>TableGen Fundamentals</h1>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]12
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]13<div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]14<ul>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]15 <li><a href="#introduction">Introduction</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]16 <ol>
17 <li><a href="#concepts">Basic concepts</a></li>
18 <li><a href="#example">An example record</a></li>
19 <li><a href="#running">Running TableGen</a></li>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]20 </ol></li>
21 <li><a href="#syntax">TableGen syntax</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]22 <ol>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]23 <li><a href="#primitives">TableGen primitives</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]24 <ol>
25 <li><a href="#comments">TableGen comments</a></li>
26 <li><a href="#types">The TableGen type system</a></li>
27 <li><a href="#values">TableGen values and expressions</a></li>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]28 </ol></li>
29 <li><a href="#classesdefs">Classes and definitions</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]30 <ol>
31 <li><a href="#valuedef">Value definitions</a></li>
32 <li><a href="#recordlet">'let' expressions</a></li>
33 <li><a href="#templateargs">Class template arguments</a></li>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]34 <li><a href="#multiclass">Multiclass definitions and instances</a></li>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]35 </ol></li>
36 <li><a href="#filescope">File scope entities</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]37 <ol>
38 <li><a href="#include">File inclusion</a></li>
39 <li><a href="#globallet">'let' expressions</a></li>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]40 </ol></li>
41 </ol></li>
42 <li><a href="#backends">TableGen backends</a>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]43 <ol>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]44 <li><a href="#">todo</a></li>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]45 </ol></li>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]46</ul>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]47</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]48
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]49<div class="doc_author">
50 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></p>
51</div>
52
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]53<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]54<h2><a name="introduction">Introduction</a></h2>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]55<!-- *********************************************************************** -->
56
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]57<div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]58
59<p>TableGen's purpose is to help a human develop and maintain records of
60domain-specific information. Because there may be a large number of these
61records, it is specifically designed to allow writing flexible descriptions and
62for common features of these records to be factored out. This reduces the
63amount of duplication in the description, reduces the chance of error, and
64makes it easier to structure domain specific information.</p>
65
66<p>The core part of TableGen <a href="#syntax">parses a file</a>, instantiates
67the declarations, and hands the result off to a domain-specific "<a
68href="#backends">TableGen backend</a>" for processing. The current major user
Chris Lattner7f500132004-07-26 21:16:55 +0000[diff] [blame]69of TableGen is the <a href="CodeGenerator.html">LLVM code generator</a>.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]70
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]71<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]72find an emacs "TableGen mode" and a vim language file in the
73<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]74distribution, respectively.</p>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]75
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]76<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]77<h3><a name="concepts">Basic concepts</a></h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]78
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]79<div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]80
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]81<p>TableGen files consist of two key parts: 'classes' and 'definitions', both
82of which are considered 'records'.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]83
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]84<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]85superclasses. The list of values is the main data that TableGen builds for each
86record; it is this that holds the domain specific information for the
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]87application. The interpretation of this data is left to a specific <a
88href="#backends">TableGen backend</a>, but the structure and format rules are
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]89taken care of and are fixed by TableGen.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]90
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]91<p><b>TableGen definitions</b> are the concrete form of 'records'. These
92generally do not have any undefined values, and are marked with the
93'<tt>def</tt>' keyword.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]94
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]95<p><b>TableGen classes</b> are abstract records that are used to build and
96describe other records. These 'classes' allow the end-user to build
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]97abstractions for either the domain they are targeting (such as "Register",
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]98"RegisterClass", and "Instruction" in the LLVM code generator) or for the
99implementor to help factor out common properties of records (such as "FPInst",
100which is used to represent floating point instructions in the X86 backend).
101TableGen keeps track of all of the classes that are used to build up a
102definition, so the backend can find all definitions of a particular class, such
103as "Instruction".</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]104
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]105<p><b>TableGen multiclasses</b> are groups of abstract records that are
David Greene753ed8f2009-04-22 16:42:54 +0000[diff] [blame]106instantiated all at once. Each instantiation can result in multiple
107TableGen definitions. If a multiclass inherits from another multiclass,
108the definitions in the sub-multiclass become part of the current
109multiclass, as if they were declared in the current multiclass.</p>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]110
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]111</div>
112
113<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]114<h3><a name="example">An example record</a></h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]115
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]116<div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]117
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]118<p>With no other arguments, TableGen parses the specified file and prints out
119all of the classes, then all of the definitions. This is a good way to see what
120the various definitions expand to fully. Running this on the <tt>X86.td</tt>
121file prints this (at the time of this writing):</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]122
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]123<div class="doc_code">
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]124<pre>
125...
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]126<b>def</b> ADD32rr { <i>// Instruction X86Inst I</i>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]127 <b>string</b> Namespace = "X86";
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]128 <b>dag</b> OutOperandList = (outs GR32:$dst);
129 <b>dag</b> InOperandList = (ins GR32:$src1, GR32:$src2);
130 <b>string</b> AsmString = "add{l}\t{$src2, $dst|$dst, $src2}";
131 <b>list</b>&lt;dag&gt; Pattern = [(set GR32:$dst, (add GR32:$src1, GR32:$src2))];
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]132 <b>list</b>&lt;Register&gt; Uses = [];
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]133 <b>list</b>&lt;Register&gt; Defs = [EFLAGS];
134 <b>list</b>&lt;Predicate&gt; Predicates = [];
135 <b>int</b> CodeSize = 3;
136 <b>int</b> AddedComplexity = 0;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]137 <b>bit</b> isReturn = 0;
138 <b>bit</b> isBranch = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]139 <b>bit</b> isIndirectBranch = 0;
140 <b>bit</b> isBarrier = 0;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]141 <b>bit</b> isCall = 0;
Dan Gohman69cc2cb2008-12-03 18:15:48 +0000[diff] [blame]142 <b>bit</b> canFoldAsLoad = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]143 <b>bit</b> mayLoad = 0;
144 <b>bit</b> mayStore = 0;
145 <b>bit</b> isImplicitDef = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]146 <b>bit</b> isConvertibleToThreeAddress = 1;
147 <b>bit</b> isCommutable = 1;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]148 <b>bit</b> isTerminator = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]149 <b>bit</b> isReMaterializable = 0;
150 <b>bit</b> isPredicable = 0;
151 <b>bit</b> hasDelaySlot = 0;
Dan Gohman453d64c2009-10-29 18:10:34 +0000[diff] [blame]152 <b>bit</b> usesCustomInserter = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]153 <b>bit</b> hasCtrlDep = 0;
154 <b>bit</b> isNotDuplicable = 0;
155 <b>bit</b> hasSideEffects = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]156 <b>bit</b> neverHasSideEffects = 0;
157 InstrItinClass Itinerary = NoItinerary;
158 <b>string</b> Constraints = "";
159 <b>string</b> DisableEncoding = "";
160 <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]161 Format Form = MRMDestReg;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]162 <b>bits</b>&lt;6&gt; FormBits = { 0, 0, 0, 0, 1, 1 };
163 ImmType ImmT = NoImm;
164 <b>bits</b>&lt;3&gt; ImmTypeBits = { 0, 0, 0 };
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]165 <b>bit</b> hasOpSizePrefix = 0;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]166 <b>bit</b> hasAdSizePrefix = 0;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]167 <b>bits</b>&lt;4&gt; Prefix = { 0, 0, 0, 0 };
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]168 <b>bit</b> hasREX_WPrefix = 0;
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]169 FPFormat FPForm = ?;
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]170 <b>bits</b>&lt;3&gt; FPFormBits = { 0, 0, 0 };
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]171}
172...
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]173</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]174</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]175
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]176<p>This definition corresponds to a 32-bit register-register add instruction in
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]177the X86. The string after the '<tt>def</tt>' string indicates the name of the
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]178record&mdash;"<tt>ADD32rr</tt>" in this case&mdash;and the comment at the end of
179the line indicates the superclasses of the definition. The body of the record
180contains all of the data that TableGen assembled for the record, indicating that
181the instruction is part of the "X86" namespace, the pattern indicating how the
182the instruction should be emitted into the assembly file, that it is a
183two-address instruction, has a particular encoding, etc. The contents and
184semantics of the information in the record is specific to the needs of the X86
185backend, and is only shown as an example.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]186
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]187<p>As you can see, a lot of information is needed for every instruction
188supported by the code generator, and specifying it all manually would be
Dan Gohman5aa39192010-02-26 02:15:17 +0000[diff] [blame]189unmaintainable, prone to bugs, and tiring to do in the first place. Because we
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]190are using TableGen, all of the information was derived from the following
191definition:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]192
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]193<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]194<pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]195let Defs = [EFLAGS],
196 isCommutable = 1, <i>// X = ADD Y,Z --&gt; X = ADD Z,Y</i>
197 isConvertibleToThreeAddress = 1 <b>in</b> <i>// Can transform into LEA.</i>
198def ADD32rr : I&lt;0x01, MRMDestReg, (outs GR32:$dst),
199 (ins GR32:$src1, GR32:$src2),
200 "add{l}\t{$src2, $dst|$dst, $src2}",
201 [(set GR32:$dst, (add GR32:$src1, GR32:$src2))]&gt;;
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]202</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]203</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]204
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]205<p>This definition makes use of the custom class <tt>I</tt> (extended from the
206custom class <tt>X86Inst</tt>), which is defined in the X86-specific TableGen
207file, to factor out the common features that instructions of its class share. A
208key feature of TableGen is that it allows the end-user to define the
209abstractions they prefer to use when describing their information.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]210
David Greenee7c3ea92011-10-19 13:04:56 +0000[diff] [blame]211<p>Each def record has a special entry called "NAME." This is the
212name of the def ("ADD32rr" above). In the general case def names can
213be formed from various kinds of string processing expressions and NAME
214resolves to the final value obtained after resolving all of those
215expressions. The user may refer to NAME anywhere she desires to use
216the ultimate name of the def. NAME should not be defined anywhere
217else in user code to avoid conflict problems.</p>
218
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]219</div>
220
221<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]222<h3><a name="running">Running TableGen</a></h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]223
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]224<div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]225
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]226<p>TableGen runs just like any other LLVM tool. The first (optional) argument
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]227specifies the file to read. If a filename is not specified, <tt>tblgen</tt>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]228reads from standard input.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]229
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]230<p>To be useful, one of the <a href="#backends">TableGen backends</a> must be
231used. These backends are selectable on the command line (type '<tt>tblgen
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]232-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]233that subclass a particular type (which can be useful for building up an enum
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]234list of these records), use the <tt>-print-enums</tt> option:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]235
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]236<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]237<pre>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]238$ tblgen X86.td -print-enums -class=Register
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]239AH, AL, AX, BH, BL, BP, BPL, BX, CH, CL, CX, DH, DI, DIL, DL, DX, EAX, EBP, EBX,
240ECX, EDI, EDX, EFLAGS, EIP, ESI, ESP, FP0, FP1, FP2, FP3, FP4, FP5, FP6, IP,
241MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7, R10, R10B, R10D, R10W, R11, R11B, R11D,
242R11W, R12, R12B, R12D, R12W, R13, R13B, R13D, R13W, R14, R14B, R14D, R14W, R15,
243R15B, R15D, R15W, R8, R8B, R8D, R8W, R9, R9B, R9D, R9W, RAX, RBP, RBX, RCX, RDI,
244RDX, RIP, RSI, RSP, SI, SIL, SP, SPL, ST0, ST1, ST2, ST3, ST4, ST5, ST6, ST7,
245XMM0, XMM1, XMM10, XMM11, XMM12, XMM13, XMM14, XMM15, XMM2, XMM3, XMM4, XMM5,
246XMM6, XMM7, XMM8, XMM9,
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]247
248$ tblgen X86.td -print-enums -class=Instruction
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]249ABS_F, ABS_Fp32, ABS_Fp64, ABS_Fp80, ADC32mi, ADC32mi8, ADC32mr, ADC32ri,
250ADC32ri8, ADC32rm, ADC32rr, ADC64mi32, ADC64mi8, ADC64mr, ADC64ri32, ADC64ri8,
251ADC64rm, ADC64rr, ADD16mi, ADD16mi8, ADD16mr, ADD16ri, ADD16ri8, ADD16rm,
252ADD16rr, ADD32mi, ADD32mi8, ADD32mr, ADD32ri, ADD32ri8, ADD32rm, ADD32rr,
253ADD64mi32, ADD64mi8, ADD64mr, ADD64ri32, ...
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]254</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]255</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]256
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]257<p>The default backend prints out all of the records, as described <a
258href="#example">above</a>.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]259
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]260<p>If you plan to use TableGen, you will most likely have to <a
261href="#backends">write a backend</a> that extracts the information specific to
262what you need and formats it in the appropriate way.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]263
264</div>
265
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]266</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]267
268<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]269<h2><a name="syntax">TableGen syntax</a></h2>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]270<!-- *********************************************************************** -->
271
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]272<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]273
274<p>TableGen doesn't care about the meaning of data (that is up to the backend to
275define), but it does care about syntax, and it enforces a simple type system.
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]276This section describes the syntax and the constructs allowed in a TableGen file.
277</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]278
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]279<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]280<h3><a name="primitives">TableGen primitives</a></h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]281
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]282<div>
283
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]284<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]285<h4><a name="comments">TableGen comments</a></h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]286
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]287<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]288
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]289<p>TableGen supports BCPL style "<tt>//</tt>" comments, which run to the end of
290the line, and it also supports <b>nestable</b> "<tt>/* */</tt>" comments.</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]291
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]292</div>
293
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]294<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]295<h4>
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]296 <a name="types">The TableGen type system</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]297</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]298
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]299<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]300
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]301<p>TableGen files are strongly typed, in a simple (but complete) type-system.
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]302These types are used to perform automatic conversions, check for errors, and to
303help interface designers constrain the input that they allow. Every <a
304href="#valuedef">value definition</a> is required to have an associated type.
305</p>
306
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]307<p>TableGen supports a mixture of very low-level types (such as <tt>bit</tt>)
308and very high-level types (such as <tt>dag</tt>). This flexibility is what
309allows it to describe a wide range of information conveniently and compactly.
310The TableGen types are:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]311
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]312<dl>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]313<dt><tt><b>bit</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]314 <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]315
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]316<dt><tt><b>int</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]317 <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]318
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]319<dt><tt><b>string</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]320 <dd>The 'string' type represents an ordered sequence of characters of
321 arbitrary length.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]322
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]323<dt><tt><b>bits</b>&lt;n&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]324 <dd>A 'bits' type is an arbitrary, but fixed, size integer that is broken up
325 into individual bits. This type is useful because it can handle some bits
326 being defined while others are undefined.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]327
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]328<dt><tt><b>list</b>&lt;ty&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]329 <dd>This type represents a list whose elements are some other type. The
330 contained type is arbitrary: it can even be another list type.</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]331
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]332<dt>Class type</dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]333 <dd>Specifying a class name in a type context means that the defined value
334 must be a subclass of the specified class. This is useful in conjunction with
335 the <b><tt>list</tt></b> type, for example, to constrain the elements of the
336 list to a common base class (e.g., a <tt><b>list</b>&lt;Register&gt;</tt> can
337 only contain definitions derived from the "<tt>Register</tt>" class).</dd>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]338
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]339<dt><tt><b>dag</b></tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]340 <dd>This type represents a nestable directed graph of elements.</dd>
341
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]342<dt><tt><b>code</b></tt></dt>
Chris Lattner28175bf2010-04-22 16:45:27 +0000[diff] [blame]343 <dd>This represents a big hunk of text. This is lexically distinct from
344 string values because it doesn't require escapeing double quotes and other
345 common characters that occur in code.</dd>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]346</dl>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]347
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]348<p>To date, these types have been sufficient for describing things that
349TableGen has been used for, but it is straight-forward to extend this list if
350needed.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]351
352</div>
353
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]354<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]355<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]356 <a name="values">TableGen values and expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]357</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]358
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]359<div>
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]360
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]361<p>TableGen allows for a pretty reasonable number of different expression forms
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]362when building up values. These forms allow the TableGen file to be written in a
363natural syntax and flavor for the application. The current expression forms
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]364supported include:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]365
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]366<dl>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]367<dt><tt>?</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]368 <dd>uninitialized field</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]369<dt><tt>0b1001011</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]370 <dd>binary integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]371<dt><tt>07654321</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]372 <dd>octal integer value (indicated by a leading 0)</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]373<dt><tt>7</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]374 <dd>decimal integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]375<dt><tt>0x7F</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]376 <dd>hexadecimal integer value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]377<dt><tt>"foo"</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]378 <dd>string value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]379<dt><tt>[{ ... }]</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]380 <dd>code fragment</dd>
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]381<dt><tt>[ X, Y, Z ]&lt;type&gt;</tt></dt>
382 <dd>list value. &lt;type&gt; is the type of the list
David Greene26433c22009-06-08 22:38:07 +0000[diff] [blame]383element and is usually optional. In rare cases,
384TableGen is unable to deduce the element type in
385which case the user must specify it explicitly.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]386<dt><tt>{ a, b, c }</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]387 <dd>initializer for a "bits&lt;3&gt;" value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]388<dt><tt>value</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]389 <dd>value reference</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]390<dt><tt>value{17}</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]391 <dd>access to one bit of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]392<dt><tt>value{15-17}</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]393 <dd>access to multiple bits of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]394<dt><tt>DEF</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]395 <dd>reference to a record definition</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]396<dt><tt>CLASS&lt;val list&gt;</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]397 <dd>reference to a new anonymous definition of CLASS with the specified
398 template arguments.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]399<dt><tt>X.Y</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]400 <dd>reference to the subfield of a value</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]401<dt><tt>list[4-7,17,2-3]</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]402 <dd>A slice of the 'list' list, including elements 4,5,6,7,17,2, and 3 from
403 it. Elements may be included multiple times.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]404<dt><tt>(DEF a, b)</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]405 <dd>a dag value. The first element is required to be a record definition, the
406 remaining elements in the list may be arbitrary other values, including nested
407 `<tt>dag</tt>' values.</dd>
Bill Wendling8402d022008-02-12 07:09:05 +0000[diff] [blame]408<dt><tt>!strconcat(a, b)</tt></dt>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]409 <dd>A string value that is the result of concatenating the 'a' and 'b'
410 strings.</dd>
David Greenefba251f2011-10-19 13:04:59 +0000[diff] [blame]411<dt><tt>str1#str2</tt></dt>
412 <dd>"#" (paste) is a shorthand for !strconcat. It may concatenate
413 things that are not quoted strings, in which case an implicit
414 !cast<string> is done on the operand of the paste.</dd>
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]415<dt><tt>!cast&lt;type&gt;(a)</tt></dt>
David Greenee8f3b272009-05-14 21:22:49 +0000[diff] [blame]416 <dd>A symbol of type <em>type</em> obtained by looking up the string 'a' in
417the symbol table. If the type of 'a' does not match <em>type</em>, TableGen
Benjamin Kramereaccdd32009-08-05 15:42:44 +0000[diff] [blame]418aborts 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]419be an object defined by a 'def' construct.</dd>
David Greene98ed3c72009-05-14 21:54:42 +0000[diff] [blame]420<dt><tt>!subst(a, b, c)</tt></dt>
421 <dd>If 'a' and 'b' are of string type or are symbol references, substitute
422'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]423<dt><tt>!foreach(a, b, c)</tt></dt>
424 <dd>For each member 'b' of dag or list 'a' apply operator 'c.' 'b' is a
425dummy variable that should be declared as a member variable of an instantiated
426class. This operation is analogous to $(foreach) in GNU make.</dd>
David Greene2f7cf7f2011-01-07 17:05:37 +0000[diff] [blame]427<dt><tt>!head(a)</tt></dt>
David Greened571b3c2009-05-14 22:38:31 +0000[diff] [blame]428 <dd>The first element of list 'a.'</dd>
David Greene2f7cf7f2011-01-07 17:05:37 +0000[diff] [blame]429<dt><tt>!tail(a)</tt></dt>
David Greened571b3c2009-05-14 22:38:31 +0000[diff] [blame]430 <dd>The 2nd-N elements of list 'a.'</dd>
David Greene2f7cf7f2011-01-07 17:05:37 +0000[diff] [blame]431<dt><tt>!empty(a)</tt></dt>
David Greened571b3c2009-05-14 22:38:31 +0000[diff] [blame]432 <dd>An integer {0,1} indicating whether list 'a' is empty.</dd>
David Greene3587eed2009-05-14 23:26:46 +0000[diff] [blame]433<dt><tt>!if(a,b,c)</tt></dt>
Bruno Cardoso Lopes4d1d7982010-06-17 00:31:36 +0000[diff] [blame]434 <dd>'b' if the result of 'int' or 'bit' operator 'a' is nonzero,
435 'c' otherwise.</dd>
David Greene297bfe62010-01-05 19:11:42 +0000[diff] [blame]436<dt><tt>!eq(a,b)</tt></dt>
Chris Lattner7ff33462010-10-31 19:22:57 +0000[diff] [blame]437 <dd>'bit 1' if string a is equal to string b, 0 otherwise. This
Benjamin Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]438 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]439 compare other types of objects.</dd>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]440</dl>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]441
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]442<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]443for different types. These rules allow you to assign a value like "<tt>7</tt>"
444to a "<tt>bits&lt;4&gt;</tt>" value, for example.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]445
446</div>
447
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]448</div>
449
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]450<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]451<h3>
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]452 <a name="classesdefs">Classes and definitions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]453</h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]454
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]455<div>
Misha Brukman94192b62004-06-03 16:59:59 +0000[diff] [blame]456
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]457<p>As mentioned in the <a href="#concepts">intro</a>, classes and definitions
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]458(collectively known as 'records') in TableGen are the main high-level unit of
459information that TableGen collects. Records are defined with a <tt>def</tt> or
460<tt>class</tt> keyword, the record name, and an optional list of "<a
Misha Brukman31551592004-06-03 23:42:24 +0000[diff] [blame]461href="#templateargs">template arguments</a>". If the record has superclasses,
Jeff Cohendd24d7c2005-10-24 16:54:55 +0000[diff] [blame]462they are specified as a comma separated list that starts with a colon character
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]463("<tt>:</tt>"). If <a href="#valuedef">value definitions</a> or <a
464href="#recordlet">let expressions</a> are needed for the class, they are
465enclosed in curly braces ("<tt>{}</tt>"); otherwise, the record ends with a
466semicolon.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]467
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]468<p>Here is a simple TableGen file:</p>
469
470<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]471<pre>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]472<b>class</b> C { <b>bit</b> V = 1; }
473<b>def</b> X : C;
474<b>def</b> Y : C {
475 <b>string</b> Greeting = "hello";
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]476}
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]477</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]478</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]479
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]480<p>This example defines two definitions, <tt>X</tt> and <tt>Y</tt>, both of
481which derive from the <tt>C</tt> class. Because of this, they both get the
482<tt>V</tt> bit value. The <tt>Y</tt> definition also gets the Greeting member
483as well.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]484
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]485<p>In general, classes are useful for collecting together the commonality
486between a group of records and isolating it in a single place. Also, classes
487permit the specification of default values for their subclasses, allowing the
488subclasses to override them as they wish.</p>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]489
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]490<!---------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]491<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]492 <a name="valuedef">Value definitions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]493</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]494
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]495<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]496
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]497<p>Value definitions define named entries in records. A value must be defined
John Criswell407f6d42004-02-12 18:11:53 +0000[diff] [blame]498before it can be referred to as the operand for another value definition or
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]499before the value is reset with a <a href="#recordlet">let expression</a>. A
500value is defined by specifying a <a href="#types">TableGen type</a> and a name.
501If an initial value is available, it may be specified after the type with an
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]502equal sign. Value definitions require terminating semicolons.</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]503
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]504</div>
505
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]506<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]507<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]508 <a name="recordlet">'let' expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]509</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]510
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]511<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]512
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]513<p>A record-level let expression is used to change the value of a value
514definition in a record. This is primarily useful when a superclass defines a
515value that a derived class or definition wants to override. Let expressions
516consist of the '<tt>let</tt>' keyword followed by a value name, an equal sign
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]517("<tt>=</tt>"), and a new value. For example, a new class could be added to the
518example above, redefining the <tt>V</tt> field for all of its subclasses:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]519
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]520<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]521<pre>
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]522<b>class</b> D : C { let V = 0; }
523<b>def</b> Z : D;
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]524</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]525</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]526
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]527<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]528value, despite the fact that it derives (indirectly) from the <tt>C</tt> class,
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]529because the <tt>D</tt> class overrode its value.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]530
531</div>
532
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]533<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]534<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]535 <a name="templateargs">Class template arguments</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]536</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]537
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]538<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]539
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]540<p>TableGen permits the definition of parameterized classes as well as normal
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]541concrete classes. Parameterized TableGen classes specify a list of variable
542bindings (which may optionally have defaults) that are bound when used. Here is
543a simple example:</p>
544
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]545<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]546<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]547<b>class</b> FPFormat&lt;<b>bits</b>&lt;3&gt; val&gt; {
548 <b>bits</b>&lt;3&gt; Value = val;
549}
550<b>def</b> NotFP : FPFormat&lt;0&gt;;
551<b>def</b> ZeroArgFP : FPFormat&lt;1&gt;;
552<b>def</b> OneArgFP : FPFormat&lt;2&gt;;
553<b>def</b> OneArgFPRW : FPFormat&lt;3&gt;;
554<b>def</b> TwoArgFP : FPFormat&lt;4&gt;;
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]555<b>def</b> CompareFP : FPFormat&lt;5&gt;;
556<b>def</b> CondMovFP : FPFormat&lt;6&gt;;
557<b>def</b> SpecialFP : FPFormat&lt;7&gt;;
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]558</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]559</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]560
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]561<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]562a list of "enumeration values", each with a "<tt>Value</tt>" field set to the
563specified integer.</p>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]564
565<p>The more esoteric forms of <a href="#values">TableGen expressions</a> are
566useful in conjunction with template arguments. As an example:</p>
567
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]568<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]569<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]570<b>class</b> ModRefVal&lt;<b>bits</b>&lt;2&gt; val&gt; {
571 <b>bits</b>&lt;2&gt; Value = val;
572}
573
574<b>def</b> None : ModRefVal&lt;0&gt;;
575<b>def</b> Mod : ModRefVal&lt;1&gt;;
576<b>def</b> Ref : ModRefVal&lt;2&gt;;
577<b>def</b> ModRef : ModRefVal&lt;3&gt;;
578
579<b>class</b> Value&lt;ModRefVal MR&gt; {
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]580 <i>// Decode some information into a more convenient format, while providing
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]581 // a nice interface to the user of the "Value" class.</i>
582 <b>bit</b> isMod = MR.Value{0};
583 <b>bit</b> isRef = MR.Value{1};
584
585 <i>// other stuff...</i>
586}
587
588<i>// Example uses</i>
589<b>def</b> bork : Value&lt;Mod&gt;;
590<b>def</b> zork : Value&lt;Ref&gt;;
591<b>def</b> hork : Value&lt;ModRef&gt;;
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]592</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]593</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]594
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]595<p>This is obviously a contrived example, but it shows how template arguments
596can 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]597actual internal data representation expected by the class. In this case,
598running <tt>tblgen</tt> on the example prints the following definitions:</p>
599
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]600<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]601<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]602<b>def</b> bork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]603 <b>bit</b> isMod = 1;
604 <b>bit</b> isRef = 0;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]605}
606<b>def</b> hork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]607 <b>bit</b> isMod = 1;
608 <b>bit</b> isRef = 1;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]609}
610<b>def</b> zork { <i>// Value</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]611 <b>bit</b> isMod = 0;
612 <b>bit</b> isRef = 1;
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]613}
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]614</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]615</div>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]616
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]617<p> This shows that TableGen was able to dig into the argument and extract a
618piece of information that was requested by the designer of the "Value" class.
619For more realistic examples, please see existing users of TableGen, such as the
620X86 backend.</p>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]621
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]622</div>
623
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]624<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]625<h4>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]626 <a name="multiclass">Multiclass definitions and instances</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]627</h4>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]628
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]629<div>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]630
631<p>
632While classes with template arguments are a good way to factor commonality
633between two instances of a definition, multiclasses allow a convenient notation
634for defining multiple definitions at once (instances of implicitly constructed
635classes). For example, consider an 3-address instruction set whose instructions
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]636come in two forms: "<tt>reg = reg op reg</tt>" and "<tt>reg = reg op imm</tt>"
637(e.g. SPARC). In this case, you'd like to specify in one place that this
638commonality exists, then in a separate place indicate what all the ops are.
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]639</p>
640
641<p>
642Here is an example TableGen fragment that shows this idea:
643</p>
644
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]645<div class="doc_code">
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]646<pre>
647<b>def</b> ops;
648<b>def</b> GPR;
649<b>def</b> Imm;
650<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
651
652<b>multiclass</b> ri_inst&lt;<b>int</b> opc, <b>string</b> asmstr&gt; {
653 def _rr : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
654 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
655 def _ri : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
656 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
657}
658
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]659<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]660<b>defm</b> ADD : ri_inst&lt;0b111, "add"&gt;;
661<b>defm</b> SUB : ri_inst&lt;0b101, "sub"&gt;;
662<b>defm</b> MUL : ri_inst&lt;0b100, "mul"&gt;;
663...
664</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]665</div>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]666
Chris Lattner28368122006-09-01 22:01:36 +0000[diff] [blame]667<p>The name of the resultant definitions has the multidef fragment names
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]668 appended to them, so this defines <tt>ADD_rr</tt>, <tt>ADD_ri</tt>,
David Greenef00919a2009-04-22 22:17:51 +0000[diff] [blame]669 <tt>SUB_rr</tt>, etc. A defm may inherit from multiple multiclasses,
670 instantiating definitions from each multiclass. Using a multiclass
671 this way is exactly equivalent to instantiating the classes multiple
672 times yourself, e.g. by writing:</p>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]673
674<div class="doc_code">
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]675<pre>
676<b>def</b> ops;
677<b>def</b> GPR;
678<b>def</b> Imm;
679<b>class</b> inst&lt;<b>int</b> opc, <b>string</b> asmstr, <b>dag</b> operandlist&gt;;
680
681<b>class</b> rrinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
682 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
683 (ops GPR:$dst, GPR:$src1, GPR:$src2)&gt;;
684
685<b>class</b> riinst&lt;<b>int</b> opc, <b>string</b> asmstr&gt;
686 : inst&lt;opc, !strconcat(asmstr, " $dst, $src1, $src2"),
687 (ops GPR:$dst, GPR:$src1, Imm:$src2)&gt;;
688
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]689<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]690<b>def</b> ADD_rr : rrinst&lt;0b111, "add"&gt;;
691<b>def</b> ADD_ri : riinst&lt;0b111, "add"&gt;;
692<b>def</b> SUB_rr : rrinst&lt;0b101, "sub"&gt;;
693<b>def</b> SUB_ri : riinst&lt;0b101, "sub"&gt;;
694<b>def</b> MUL_rr : rrinst&lt;0b100, "mul"&gt;;
695<b>def</b> MUL_ri : riinst&lt;0b100, "mul"&gt;;
696...
697</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]698</div>
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]699
Bruno Cardoso Lopesc4f61482010-06-05 02:11:52 +0000[diff] [blame]700<p>
701A defm can also be used inside a multiclass providing several levels of
702multiclass instanciations.
703</p>
704
705<div class="doc_code">
706<pre>
707<b>class</b> Instruction&lt;bits&lt;4&gt; opc, string Name&gt; {
708 bits&lt;4&gt; opcode = opc;
709 string name = Name;
710}
711
712<b>multiclass</b> basic_r&lt;bits&lt;4&gt; opc&gt; {
713 <b>def</b> rr : Instruction&lt;opc, "rr"&gt;;
714 <b>def</b> rm : Instruction&lt;opc, "rm"&gt;;
715}
716
717<b>multiclass</b> basic_s&lt;bits&lt;4&gt; opc&gt; {
718 <b>defm</b> SS : basic_r&lt;opc&gt;;
719 <b>defm</b> SD : basic_r&lt;opc&gt;;
720 <b>def</b> X : Instruction&lt;opc, "x"&gt;;
721}
722
723<b>multiclass</b> basic_p&lt;bits&lt;4&gt; opc&gt; {
724 <b>defm</b> PS : basic_r&lt;opc&gt;;
725 <b>defm</b> PD : basic_r&lt;opc&gt;;
726 <b>def</b> Y : Instruction&lt;opc, "y"&gt;;
727}
728
729<b>defm</b> ADD : basic_s&lt;0xf&gt;, basic_p&lt;0xf&gt;;
730...
731
732<i>// Results</i>
733<b>def</b> ADDPDrm { ...
734<b>def</b> ADDPDrr { ...
735<b>def</b> ADDPSrm { ...
736<b>def</b> ADDPSrr { ...
737<b>def</b> ADDSDrm { ...
738<b>def</b> ADDSDrr { ...
739<b>def</b> ADDY { ...
740<b>def</b> ADDX { ...
741</pre>
742</div>
743
Bruno Cardoso Lopes23f83212010-06-18 19:53:41 +0000[diff] [blame]744<p>
745defm declarations can inherit from classes too, the
746rule to follow is that the class list must start after the
747last multiclass, and there must be at least one multiclass
748before them.
749</p>
750
751<div class="doc_code">
752<pre>
753<b>class</b> XD { bits&lt;4&gt; Prefix = 11; }
754<b>class</b> XS { bits&lt;4&gt; Prefix = 12; }
755
756<b>class</b> I&lt;bits<4&gt; op> {
757 bits&lt;4&gt; opcode = op;
758}
759
760<b>multiclass</b> R {
761 <b>def</b> rr : I&lt;4&gt;;
762 <b>def</b> rm : I&lt;2&gt;;
763}
764
765<b>multiclass</b> Y {
766 <b>defm</b> SS : R, XD;
767 <b>defm</b> SD : R, XS;
768}
769
770<b>defm</b> Instr : Y;
771
772<i>// Results</i>
773<b>def</b> InstrSDrm {
774 bits&lt;4&gt; opcode = { 0, 0, 1, 0 };
775 bits&lt;4&gt; Prefix = { 1, 1, 0, 0 };
776}
777...
778<b>def</b> InstrSSrr {
779 bits&lt;4&gt; opcode = { 0, 1, 0, 0 };
780 bits&lt;4&gt; Prefix = { 1, 0, 1, 1 };
781}
782</pre>
783</div>
784
Chris Lattnerf01a85b2006-09-01 21:44:18 +0000[diff] [blame]785</div>
786
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]787</div>
788
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]789<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]790<h3>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]791 <a name="filescope">File scope entities</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]792</h3>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]793
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]794<div>
795
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]796<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]797<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]798 <a name="include">File inclusion</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]799</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]800
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]801<div>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]802<p>TableGen supports the '<tt>include</tt>' token, which textually substitutes
803the specified file in place of the include directive. The filename should be
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]804specified as a double quoted string immediately after the '<tt>include</tt>'
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]805keyword. Example:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]806
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]807<div class="doc_code">
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]808<pre>
Chris Lattner55927232004-02-06 06:37:00 +0000[diff] [blame]809<b>include</b> "foo.td"
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]810</pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]811</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]812
813</div>
814
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]815<!-- -------------------------------------------------------------------------->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]816<h4>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]817 <a name="globallet">'let' expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]818</h4>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]819
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]820<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]821
822<p>"Let" expressions at file scope are similar to <a href="#recordlet">"let"
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]823expressions within a record</a>, except they can specify a value binding for
824multiple records at a time, and may be useful in certain other cases.
825File-scope let expressions are really just another way that TableGen allows the
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]826end-user to factor out commonality from the records.</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]827
Jeff Cohendd24d7c2005-10-24 16:54:55 +0000[diff] [blame]828<p>File-scope "let" expressions take a comma-separated list of bindings to
Matthijs Kooijman3abb3082008-10-20 08:45:34 +0000[diff] [blame]829apply, and one or more records to bind the values in. Here are some
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]830examples:</p>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]831
Bill Wendling7a05f002010-12-08 02:46:25 +0000[diff] [blame]832<div class="doc_code">
833<pre>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]834<b>let</b> isTerminator = 1, isReturn = 1, isBarrier = 1, hasCtrlDep = 1 <b>in</b>
835 <b>def</b> RET : I&lt;0xC3, RawFrm, (outs), (ins), "ret", [(X86retflag 0)]&gt;;
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]836
Chris Lattner1215e322004-02-06 06:04:25 +0000[diff] [blame]837<b>let</b> isCall = 1 <b>in</b>
838 <i>// All calls clobber the non-callee saved registers...</i>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]839 <b>let</b> Defs = [EAX, ECX, EDX, FP0, FP1, FP2, FP3, FP4, FP5, FP6, ST0,
840 MM0, MM1, MM2, MM3, MM4, MM5, MM6, MM7,
841 XMM0, XMM1, XMM2, XMM3, XMM4, XMM5, XMM6, XMM7, EFLAGS] <b>in</b> {
Dan Gohman2ed27532008-10-14 17:00:38 +0000[diff] [blame]842 <b>def</b> CALLpcrel32 : Ii32&lt;0xE8, RawFrm, (outs), (ins i32imm:$dst,variable_ops),
843 "call\t${dst:call}", []&gt;;
844 <b>def</b> CALL32r : I&lt;0xFF, MRM2r, (outs), (ins GR32:$dst, variable_ops),
845 "call\t{*}$dst", [(X86call GR32:$dst)]&gt;;
846 <b>def</b> CALL32m : I&lt;0xFF, MRM2m, (outs), (ins i32mem:$dst, variable_ops),
847 "call\t{*}$dst", []&gt;;
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]848 }
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]849</pre>
Bill Wendling7a05f002010-12-08 02:46:25 +0000[diff] [blame]850</div>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]851
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]852<p>File-scope "let" expressions are often useful when a couple of definitions
853need 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]854opened, as in the case with the <tt>CALL*</tt> instructions above.</p>
855
Bruno Cardoso Lopes5f2adcc2010-06-10 02:42:59 +0000[diff] [blame]856<p>It's also possible to use "let" expressions inside multiclasses, providing
857more ways to factor out commonality from the records, specially if using
858several levels of multiclass instanciations. This also avoids the need of using
859"let" expressions within subsequent records inside a multiclass.</p>
860
Benjamin Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]861<pre class="doc_code">
Bruno Cardoso Lopes5f2adcc2010-06-10 02:42:59 +0000[diff] [blame]862<b>multiclass </b>basic_r&lt;bits&lt;4&gt; opc&gt; {
863 <b>let </b>Predicates = [HasSSE2] in {
864 <b>def </b>rr : Instruction&lt;opc, "rr"&gt;;
865 <b>def </b>rm : Instruction&lt;opc, "rm"&gt;;
866 }
867 <b>let </b>Predicates = [HasSSE3] in
868 <b>def </b>rx : Instruction&lt;opc, "rx"&gt;;
869}
870
871<b>multiclass </b>basic_ss&lt;bits&lt;4&gt; opc&gt; {
872 <b>let </b>IsDouble = 0 in
873 <b>defm </b>SS : basic_r&lt;opc&gt;;
874
875 <b>let </b>IsDouble = 1 in
876 <b>defm </b>SD : basic_r&lt;opc&gt;;
877}
878
879<b>defm </b>ADD : basic_ss&lt;0xf&gt;;
880</pre>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]881</div>
882
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]883</div>
884
885</div>
886
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]887<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]888<h2><a name="codegen">Code Generator backend info</a></h2>
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]889<!-- *********************************************************************** -->
890
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]891<div>
Benjamin Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]892
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]893<p>Expressions used by code generator to describe instructions and isel
894patterns:</p>
895
Benjamin Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]896<dl>
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]897<dt><tt>(implicit a)</tt></dt>
898 <dd>an implicitly defined physical register. This tells the dag instruction
899 selection emitter the input pattern's extra definitions matches implicit
900 physical register definitions.</dd>
Benjamin Kramerc940bcf2010-10-30 21:07:28 +0000[diff] [blame]901</dl>
Evan Chengef716b02009-10-05 02:51:06 +0000[diff] [blame]902</div>
903
904<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]905<h2><a name="backends">TableGen backends</a></h2>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]906<!-- *********************************************************************** -->
907
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]908<div>
Bill Wendling1a19af92008-02-12 07:06:19 +0000[diff] [blame]909
910<p>TODO: How they work, how to write one. This section should not contain
911details about any particular backend, except maybe -print-enums as an example.
912This should highlight the APIs in <tt>TableGen/Record.h</tt>.</p>
913
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]914</div>
915
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]916<!-- *********************************************************************** -->
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]917
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]918<hr>
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]919<address>
920 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]921 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
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Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]924
925 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]926 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]927 Last modified: $Date$
Misha Brukman692cec02004-05-12 18:31:21 +0000[diff] [blame]928</address>
Chris Lattner149a2492004-02-06 05:42:53 +0000[diff] [blame]929
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