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10
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]11<h1>TableGen Fundamentals</h1>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]12
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]13<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]14<ul>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]15 <li><a href="#introduction">Introduction</a>
Chris Lattnerb54c99c2004-02-06 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]20 </ol></li>
21 <li><a href="#syntax">TableGen syntax</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]22 <ol>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]23 <li><a href="#primitives">TableGen primitives</a>
Chris Lattnerb54c99c2004-02-06 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]28 </ol></li>
29 <li><a href="#classesdefs">Classes and definitions</a>
Chris Lattnerb54c99c2004-02-06 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 Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]34 <li><a href="#multiclass">Multiclass definitions and instances</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]35 </ol></li>
36 <li><a href="#filescope">File scope entities</a>
Chris Lattnerb54c99c2004-02-06 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]40 </ol></li>
41 </ol></li>
42 <li><a href="#backends">TableGen backends</a>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]43 <ol>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]44 <li><a href="#">todo</a></li>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]45 </ol></li>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]46</ul>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]47</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]48
Chris Lattner7911ce22004-05-23 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]53<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]54<h2><a name="introduction">Introduction</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]55<!-- *********************************************************************** -->
56
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]57<div>
Chris Lattnerb54c99c2004-02-06 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 Lattner1aab3272004-07-26 21:16:55 +0000[diff] [blame]69of TableGen is the <a href="CodeGenerator.html">LLVM code generator</a>.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]70
Misha Brukman85234ac2004-05-12 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 Wendling643eb5d2008-02-12 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]74distribution, respectively.</p>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]75
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]76<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]77<h3><a name="concepts">Basic concepts</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]78
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]79<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]80
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]83
Misha Brukman85234ac2004-05-12 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 Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]89taken care of and are fixed by TableGen.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]90
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]94
Misha Brukman85234ac2004-05-12 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]97abstractions for either the domain they are targeting (such as "Register",
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]104
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]105<p><b>TableGen multiclasses</b> are groups of abstract records that are
David Greenede444af2009-04-22 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 Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]110
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]111</div>
112
113<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]114<h3><a name="example">An example record</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]115
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]116<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]117
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]122
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]123<div class="doc_code">
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]124<pre>
125...
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]126<b>def</b> ADD32rr { <i>// Instruction X86Inst I</i>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]127 <b>string</b> Namespace = "X86";
Bill Wendling643eb5d2008-02-12 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 Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]132 <b>list</b>&lt;Register&gt; Uses = [];
Bill Wendling643eb5d2008-02-12 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 Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]137 <b>bit</b> isReturn = 0;
138 <b>bit</b> isBranch = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]139 <b>bit</b> isIndirectBranch = 0;
140 <b>bit</b> isBarrier = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]141 <b>bit</b> isCall = 0;
Dan Gohman15511cf2008-12-03 18:15:48 +0000[diff] [blame]142 <b>bit</b> canFoldAsLoad = 0;
Bill Wendling643eb5d2008-02-12 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]146 <b>bit</b> isConvertibleToThreeAddress = 1;
147 <b>bit</b> isCommutable = 1;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]148 <b>bit</b> isTerminator = 0;
Bill Wendling643eb5d2008-02-12 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 Gohman533297b2009-10-29 18:10:34 +0000[diff] [blame]152 <b>bit</b> usesCustomInserter = 0;
Bill Wendling643eb5d2008-02-12 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 Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]161 Format Form = MRMDestReg;
Bill Wendling643eb5d2008-02-12 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 Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]165 <b>bit</b> hasOpSizePrefix = 0;
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]166 <b>bit</b> hasAdSizePrefix = 0;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]167 <b>bits</b>&lt;4&gt; Prefix = { 0, 0, 0, 0 };
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]168 <b>bit</b> hasREX_WPrefix = 0;
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]169 FPFormat FPForm = ?;
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]170 <b>bits</b>&lt;3&gt; FPFormBits = { 0, 0, 0 };
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]171}
172...
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]173</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]174</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]175
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]176<p>This definition corresponds to a 32-bit register-register add instruction in
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]177the X86. The string after the '<tt>def</tt>' string indicates the name of the
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]186
Misha Brukman85234ac2004-05-12 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 Gohman8ff4b432010-02-26 02:15:17 +0000[diff] [blame]189unmaintainable, prone to bugs, and tiring to do in the first place. Because we
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]190are using TableGen, all of the information was derived from the following
191definition:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]192
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]193<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]194<pre>
Bill Wendling643eb5d2008-02-12 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]202</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]203</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]204
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]210
David Greenedc5287c2011-10-19 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]219</div>
220
221<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]222<h3><a name="running">Running TableGen</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]223
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]224<div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]225
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]226<p>TableGen runs just like any other LLVM tool. The first (optional) argument
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]227specifies the file to read. If a filename is not specified, <tt>tblgen</tt>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]228reads from standard input.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]229
Misha Brukman85234ac2004-05-12 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]232-help</tt>' for a list). For example, to get a list of all of the definitions
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]233that subclass a particular type (which can be useful for building up an enum
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]234list of these records), use the <tt>-print-enums</tt> option:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]235
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]236<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]237<pre>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]238$ tblgen X86.td -print-enums -class=Register
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]247
248$ tblgen X86.td -print-enums -class=Instruction
Bill Wendling643eb5d2008-02-12 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]254</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]255</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]256
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]259
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]263
264</div>
265
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]266</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]267
268<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]269<h2><a name="syntax">TableGen syntax</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]270<!-- *********************************************************************** -->
271
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]272<div>
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]276This section describes the syntax and the constructs allowed in a TableGen file.
277</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]278
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]279<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]280<h3><a name="primitives">TableGen primitives</a></h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]281
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]282<div>
283
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]284<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]285<h4><a name="comments">TableGen comments</a></h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]286
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]287<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]288
Chris Lattnerb54c99c2004-02-06 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]291
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]292</div>
293
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]294<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]295<h4>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]296 <a name="types">The TableGen type system</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]297</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]298
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]299<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]300
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]301<p>TableGen files are strongly typed, in a simple (but complete) type-system.
Chris Lattnerb54c99c2004-02-06 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 Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]311
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]312<dl>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]313<dt><tt><b>bit</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]314 <dd>A 'bit' is a boolean value that can hold either 0 or 1.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]315
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]316<dt><tt><b>int</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]317 <dd>The 'int' type represents a simple 32-bit integer value, such as 5.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]318
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]319<dt><tt><b>string</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]320 <dd>The 'string' type represents an ordered sequence of characters of
321 arbitrary length.</dd>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]322
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]323<dt><tt><b>bits</b>&lt;n&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]327
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]328<dt><tt><b>list</b>&lt;ty&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]331
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]332<dt>Class type</dt>
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]338
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]339<dt><tt><b>dag</b></tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]340 <dd>This type represents a nestable directed graph of elements.</dd>
341
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]342<dt><tt><b>code</b></tt></dt>
Chris Lattnerca73cea2010-04-22 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]346</dl>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]347
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]351
352</div>
353
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]354<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]355<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]356 <a name="values">TableGen values and expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]357</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]358
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]359<div>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]360
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]361<p>TableGen allows for a pretty reasonable number of different expression forms
Chris Lattnerb54c99c2004-02-06 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]364supported include:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]365
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]366<dl>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]367<dt><tt>?</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]368 <dd>uninitialized field</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]369<dt><tt>0b1001011</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]370 <dd>binary integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]371<dt><tt>07654321</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]372 <dd>octal integer value (indicated by a leading 0)</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]373<dt><tt>7</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]374 <dd>decimal integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]375<dt><tt>0x7F</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]376 <dd>hexadecimal integer value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]377<dt><tt>"foo"</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]378 <dd>string value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]379<dt><tt>[{ ... }]</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]380 <dd>code fragment</dd>
Benjamin Kramere15192b2009-08-05 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 Greeneccbfb8d2009-06-08 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 Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]386<dt><tt>{ a, b, c }</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]387 <dd>initializer for a "bits&lt;3&gt;" value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]388<dt><tt>value</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]389 <dd>value reference</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]390<dt><tt>value{17}</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]391 <dd>access to one bit of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]392<dt><tt>value{15-17}</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]393 <dd>access to multiple bits of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]394<dt><tt>DEF</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]395 <dd>reference to a record definition</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]396<dt><tt>CLASS&lt;val list&gt;</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]397 <dd>reference to a new anonymous definition of CLASS with the specified
398 template arguments.</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]399<dt><tt>X.Y</tt></dt>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]400 <dd>reference to the subfield of a value</dd>
Bill Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]401<dt><tt>list[4-7,17,2-3]</tt></dt>
Bill Wendling643eb5d2008-02-12 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 Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]404<dt><tt>(DEF a, b)</tt></dt>
Bill Wendling643eb5d2008-02-12 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 Wendling58d96d62008-02-12 07:09:05 +0000[diff] [blame]408<dt><tt>!strconcat(a, b)</tt></dt>
Bill Wendling643eb5d2008-02-12 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 Greene40230c42011-10-19 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 Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]415<dt><tt>!cast&lt;type&gt;(a)</tt></dt>
David Greenee6c27de2009-05-14 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 Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]418aborts with an error. !cast&lt;string&gt; is a special case in that the argument must
David Greene2c026622009-06-29 20:05:29 +0000[diff] [blame]419be an object defined by a 'def' construct.</dd>
David Greene4afc5092009-05-14 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 Greenebeb31a52009-05-14 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 Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]427<dt><tt>!head(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]428 <dd>The first element of list 'a.'</dd>
David Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]429<dt><tt>!tail(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]430 <dd>The 2nd-N elements of list 'a.'</dd>
David Greene1434f662011-01-07 17:05:37 +0000[diff] [blame]431<dt><tt>!empty(a)</tt></dt>
David Greene5f9f9ba2009-05-14 22:38:31 +0000[diff] [blame]432 <dd>An integer {0,1} indicating whether list 'a' is empty.</dd>
David Greene9bea7c82009-05-14 23:26:46 +0000[diff] [blame]433<dt><tt>!if(a,b,c)</tt></dt>
Bruno Cardoso Lopeseba8f182010-06-17 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 Greene6786d5e2010-01-05 19:11:42 +0000[diff] [blame]436<dt><tt>!eq(a,b)</tt></dt>
Chris Lattner150d20e2010-10-31 19:22:57 +0000[diff] [blame]437 <dd>'bit 1' if string a is equal to string b, 0 otherwise. This
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]438 only operates on string, int and bit objects. Use !cast&lt;string&gt; to
Bruno Cardoso Lopese87de412010-06-16 23:24:12 +0000[diff] [blame]439 compare other types of objects.</dd>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]440</dl>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]441
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]442<p>Note that all of the values have rules specifying how they convert to values
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]445
446</div>
447
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]448</div>
449
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]450<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]451<h3>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]452 <a name="classesdefs">Classes and definitions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]453</h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]454
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]455<div>
Misha Brukman78b648c2004-06-03 16:59:59 +0000[diff] [blame]456
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]457<p>As mentioned in the <a href="#concepts">intro</a>, classes and definitions
Chris Lattnerb54c99c2004-02-06 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 Brukman179bf4b2004-06-03 23:42:24 +0000[diff] [blame]461href="#templateargs">template arguments</a>". If the record has superclasses,
Jeff Cohen0b81cda2005-10-24 16:54:55 +0000[diff] [blame]462they are specified as a comma separated list that starts with a colon character
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]467
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]468<p>Here is a simple TableGen file:</p>
469
470<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]471<pre>
Chris Lattnerfa6f3092004-02-06 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]476}
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]477</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]478</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]479
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]484
Misha Brukman85234ac2004-05-12 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 Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]489
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]490<!---------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]491<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]492 <a name="valuedef">Value definitions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]493</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]494
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]495<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]496
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]497<p>Value definitions define named entries in records. A value must be defined
John Criswellaa55c8c2004-02-12 18:11:53 +0000[diff] [blame]498before it can be referred to as the operand for another value definition or
Chris Lattnerb54c99c2004-02-06 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]502equal sign. Value definitions require terminating semicolons.</p>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]503
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]504</div>
505
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]506<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]507<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]508 <a name="recordlet">'let' expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]509</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]510
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]511<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]512
Misha Brukman85234ac2004-05-12 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 Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]519
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]520<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]521<pre>
Chris Lattnerfa6f3092004-02-06 06:04:25 +0000[diff] [blame]522<b>class</b> D : C { let V = 0; }
523<b>def</b> Z : D;
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]524</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]525</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]526
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]528value, despite the fact that it derives (indirectly) from the <tt>C</tt> class,
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]529because the <tt>D</tt> class overrode its value.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]530
531</div>
532
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]533<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]534<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]535 <a name="templateargs">Class template arguments</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]536</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]537
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]538<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]539
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]540<p>TableGen permits the definition of parameterized classes as well as normal
Chris Lattner23f54fa2004-02-06 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]545<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]546<pre>
Chris Lattner23f54fa2004-02-06 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 Wendling643eb5d2008-02-12 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]558</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]559</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]560
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]561<p>In this case, template arguments are used as a space efficient way to specify
Bill Wendling643eb5d2008-02-12 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 Lattner23f54fa2004-02-06 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]568<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]569<pre>
Chris Lattner23f54fa2004-02-06 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]580 <i>// Decode some information into a more convenient format, while providing
Chris Lattner23f54fa2004-02-06 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]592</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]593</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]594
Misha Brukman85234ac2004-05-12 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 Lattner23f54fa2004-02-06 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]600<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]601<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]602<b>def</b> bork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]603 <b>bit</b> isMod = 1;
604 <b>bit</b> isRef = 0;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]605}
606<b>def</b> hork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]607 <b>bit</b> isMod = 1;
608 <b>bit</b> isRef = 1;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]609}
610<b>def</b> zork { <i>// Value</i>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]611 <b>bit</b> isMod = 0;
612 <b>bit</b> isRef = 1;
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]613}
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]614</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]615</div>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]616
Misha Brukman85234ac2004-05-12 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 Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]621
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]622</div>
623
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]624<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]625<h4>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]626 <a name="multiclass">Multiclass definitions and instances</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]627</h4>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]628
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]629<div>
Chris Lattner84b35982006-09-01 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 Wendling643eb5d2008-02-12 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 Lattner84b35982006-09-01 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]645<div class="doc_code">
Chris Lattner84b35982006-09-01 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]659<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattner84b35982006-09-01 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]665</div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]666
Chris Lattnere7173e12006-09-01 22:01:36 +0000[diff] [blame]667<p>The name of the resultant definitions has the multidef fragment names
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]668 appended to them, so this defines <tt>ADD_rr</tt>, <tt>ADD_ri</tt>,
David Greene56546132009-04-22 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]673
674<div class="doc_code">
Chris Lattner84b35982006-09-01 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]689<i>// Instantiations of the ri_inst multiclass.</i>
Chris Lattner84b35982006-09-01 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]698</div>
Chris Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]699
Bruno Cardoso Lopes270562b2010-06-05 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 Lopes6e0a99a2010-06-18 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 Lattner84b35982006-09-01 21:44:18 +0000[diff] [blame]785</div>
786
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]787</div>
788
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]789<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]790<h3>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]791 <a name="filescope">File scope entities</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]792</h3>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]793
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]794<div>
795
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]796<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]797<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]798 <a name="include">File inclusion</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]799</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]800
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]801<div>
Misha Brukman85234ac2004-05-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]804specified as a double quoted string immediately after the '<tt>include</tt>'
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]805keyword. Example:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]806
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]807<div class="doc_code">
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]808<pre>
Chris Lattner23f54fa2004-02-06 06:37:00 +0000[diff] [blame]809<b>include</b> "foo.td"
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]810</pre>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]811</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]812
813</div>
814
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]815<!-- -------------------------------------------------------------------------->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]816<h4>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]817 <a name="globallet">'let' expressions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]818</h4>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]819
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]820<div>
Bill Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]821
822<p>"Let" expressions at file scope are similar to <a href="#recordlet">"let"
Chris Lattnerb54c99c2004-02-06 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 Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]826end-user to factor out commonality from the records.</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]827
Jeff Cohen0b81cda2005-10-24 16:54:55 +0000[diff] [blame]828<p>File-scope "let" expressions take a comma-separated list of bindings to
Matthijs Kooijman94199da2008-10-20 08:45:34 +0000[diff] [blame]829apply, and one or more records to bind the values in. Here are some
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]830examples:</p>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]831
Bill Wendling6171ab62010-12-08 02:46:25 +0000[diff] [blame]832<div class="doc_code">
833<pre>
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]836
Chris Lattnerfa6f3092004-02-06 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 Wendling643eb5d2008-02-12 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 Gohman364a39f2008-10-14 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]848 }
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]849</pre>
Bill Wendling6171ab62010-12-08 02:46:25 +0000[diff] [blame]850</div>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]851
Misha Brukman85234ac2004-05-12 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 Wendling643eb5d2008-02-12 07:06:19 +0000[diff] [blame]854opened, as in the case with the <tt>CALL*</tt> instructions above.</p>
855
Bruno Cardoso Lopesee65db32010-06-10 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 Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]861<pre class="doc_code">
Bruno Cardoso Lopesee65db32010-06-10 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]881</div>
882
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]883</div>
884
885</div>
886
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]887<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]888<h2><a name="codegen">Code Generator backend info</a></h2>
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]889<!-- *********************************************************************** -->
890
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]891<div>
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]892
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]893<p>Expressions used by code generator to describe instructions and isel
894patterns:</p>
895
Benjamin Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]896<dl>
Evan Cheng11f911f2009-10-05 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 Kramer943beeb2010-10-30 21:07:28 +0000[diff] [blame]901</dl>
Evan Cheng11f911f2009-10-05 02:51:06 +0000[diff] [blame]902</div>
903
904<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]905<h2><a name="backends">TableGen backends</a></h2>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]906<!-- *********************************************************************** -->
907
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]908<div>
Bill Wendling643eb5d2008-02-12 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 Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]914</div>
915
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]916<!-- *********************************************************************** -->
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]917
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]918<hr>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]919<address>
920 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]921 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]922 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]924
925 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]926 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]927 Last modified: $Date$
Misha Brukman85234ac2004-05-12 18:31:21 +0000[diff] [blame]928</address>
Chris Lattnerb54c99c2004-02-06 05:42:53 +0000[diff] [blame]929
930</body>
931</html>