1//===- TGLexer.h - Lexer for TableGen Files ---------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This class represents the Lexer for tablegen files.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_LIB_TABLEGEN_TGLEXER_H
14#define LLVM_LIB_TABLEGEN_TGLEXER_H
15
16#include "llvm/ADT/StringRef.h"
17#include "llvm/ADT/StringSet.h"
18#include "llvm/Support/DataTypes.h"
19#include "llvm/Support/SMLoc.h"
20#include <cassert>
21#include <memory>
22#include <set>
23#include <string>
24#include <vector>
25
26namespace llvm {
27template <typename T> class ArrayRef;
28class SourceMgr;
29class Twine;
30
31namespace tgtok {
32enum TokKind {
33 // Markers
34 Eof,
35 Error,
36
37 // Tokens with no info.
38 minus, // -
39 plus, // +
40 l_square, // [
41 r_square, // ]
42 l_brace, // {
43 r_brace, // }
44 l_paren, // (
45 r_paren, // )
46 less, // <
47 greater, // >
48 colon, // :
49 semi, // ;
50 comma, // ,
51 dot, // .
52 equal, // =
53 question, // ?
54 paste, // #
55 dotdotdot, // ...
56
57 // Boolean literals.
58 TrueVal,
59 FalseVal,
60
61 // Integer value.
62 IntVal,
63
64 // Binary constant. Note that these are sized according to the number of
65 // bits given.
66 BinaryIntVal,
67
68 // Preprocessing tokens for internal usage by the lexer.
69 // They are never returned as a result of Lex().
70 Ifdef,
71 Ifndef,
72 Else,
73 Endif,
74 Define,
75
76 // Reserved keywords. ('ElseKW' is named to distinguish it from the
77 // existing 'Else' that means the preprocessor #else.)
78 Bit,
79 Bits,
80 Code,
81 Dag,
82 ElseKW,
83 FalseKW,
84 Field,
85 In,
86 Include,
87 Int,
88 List,
89 String,
90 Then,
91 TrueKW,
92
93 // Object start tokens.
94 OBJECT_START_FIRST,
95 Assert = OBJECT_START_FIRST,
96 Class,
97 Def,
98 Defm,
99 Defset,
100 Deftype,
101 Defvar,
102 Dump,
103 Foreach,
104 If,
105 Let,
106 MultiClass,
107 OBJECT_START_LAST = MultiClass,
108
109 // Bang operators.
110 BANG_OPERATOR_FIRST,
111 XConcat = BANG_OPERATOR_FIRST,
112 XADD,
113 XSUB,
114 XMUL,
115 XDIV,
116 XNOT,
117 XLOG2,
118 XAND,
119 XOR,
120 XXOR,
121 XSRA,
122 XSRL,
123 XSHL,
124 XListConcat,
125 XListSplat,
126 XStrConcat,
127 XInterleave,
128 XSubstr,
129 XFind,
130 XCast,
131 XSubst,
132 XForEach,
133 XFilter,
134 XFoldl,
135 XHead,
136 XTail,
137 XSize,
138 XEmpty,
139 XIf,
140 XCond,
141 XEq,
142 XIsA,
143 XDag,
144 XNe,
145 XLe,
146 XLt,
147 XGe,
148 XGt,
149 XSetDagOp,
150 XGetDagOp,
151 XExists,
152 XListRemove,
153 XToLower,
154 XToUpper,
155 XRange,
156 XGetDagArg,
157 XGetDagName,
158 XSetDagArg,
159 XSetDagName,
160 XRepr,
161 BANG_OPERATOR_LAST = XRepr,
162
163 // String valued tokens.
164 STRING_VALUE_FIRST,
165 Id = STRING_VALUE_FIRST,
166 StrVal,
167 VarName,
168 CodeFragment,
169 STRING_VALUE_LAST = CodeFragment,
170};
171
172/// isBangOperator - Return true if this is a bang operator.
173static inline bool isBangOperator(tgtok::TokKind Kind) {
174 return tgtok::BANG_OPERATOR_FIRST <= Kind && Kind <= BANG_OPERATOR_LAST;
175}
176
177/// isObjectStart - Return true if this is a valid first token for a statement.
178static inline bool isObjectStart(tgtok::TokKind Kind) {
179 return tgtok::OBJECT_START_FIRST <= Kind && Kind <= OBJECT_START_LAST;
180}
181
182/// isStringValue - Return true if this is a string value.
183static inline bool isStringValue(tgtok::TokKind Kind) {
184 return tgtok::STRING_VALUE_FIRST <= Kind && Kind <= STRING_VALUE_LAST;
185}
186} // namespace tgtok
187
188/// TGLexer - TableGen Lexer class.
189class TGLexer {
190 SourceMgr &SrcMgr;
191
192 const char *CurPtr = nullptr;
193 StringRef CurBuf;
194
195 // Information about the current token.
196 const char *TokStart = nullptr;
197 tgtok::TokKind CurCode = tgtok::TokKind::Eof;
198 std::string CurStrVal; // This is valid for Id, StrVal, VarName, CodeFragment
199 int64_t CurIntVal = 0; // This is valid for IntVal.
200
201 /// CurBuffer - This is the current buffer index we're lexing from as managed
202 /// by the SourceMgr object.
203 unsigned CurBuffer = 0;
204
205public:
206 typedef std::set<std::string> DependenciesSetTy;
207
208private:
209 /// Dependencies - This is the list of all included files.
210 DependenciesSetTy Dependencies;
211
212public:
213 TGLexer(SourceMgr &SrcMgr, ArrayRef<std::string> Macros);
214
215 tgtok::TokKind Lex() {
216 return CurCode = LexToken(FileOrLineStart: CurPtr == CurBuf.begin());
217 }
218
219 const DependenciesSetTy &getDependencies() const {
220 return Dependencies;
221 }
222
223 tgtok::TokKind getCode() const { return CurCode; }
224
225 const std::string &getCurStrVal() const {
226 assert(tgtok::isStringValue(CurCode) &&
227 "This token doesn't have a string value");
228 return CurStrVal;
229 }
230 int64_t getCurIntVal() const {
231 assert(CurCode == tgtok::IntVal && "This token isn't an integer");
232 return CurIntVal;
233 }
234 std::pair<int64_t, unsigned> getCurBinaryIntVal() const {
235 assert(CurCode == tgtok::BinaryIntVal &&
236 "This token isn't a binary integer");
237 return std::make_pair(x: CurIntVal, y: (CurPtr - TokStart)-2);
238 }
239
240 SMLoc getLoc() const;
241 SMRange getLocRange() const;
242
243private:
244 /// LexToken - Read the next token and return its code.
245 tgtok::TokKind LexToken(bool FileOrLineStart = false);
246
247 tgtok::TokKind ReturnError(SMLoc Loc, const Twine &Msg);
248 tgtok::TokKind ReturnError(const char *Loc, const Twine &Msg);
249
250 int getNextChar();
251 int peekNextChar(int Index) const;
252 void SkipBCPLComment();
253 bool SkipCComment();
254 tgtok::TokKind LexIdentifier();
255 bool LexInclude();
256 tgtok::TokKind LexString();
257 tgtok::TokKind LexVarName();
258 tgtok::TokKind LexNumber();
259 tgtok::TokKind LexBracket();
260 tgtok::TokKind LexExclaim();
261
262 // Process EOF encountered in LexToken().
263 // If EOF is met in an include file, then the method will update
264 // CurPtr, CurBuf and preprocessing include stack, and return true.
265 // If EOF is met in the top-level file, then the method will
266 // update and check the preprocessing include stack, and return false.
267 bool processEOF();
268
269 // *** Structures and methods for preprocessing support ***
270
271 // A set of macro names that are defined either via command line or
272 // by using:
273 // #define NAME
274 StringSet<> DefinedMacros;
275
276 // Each of #ifdef and #else directives has a descriptor associated
277 // with it.
278 //
279 // An ordered list of preprocessing controls defined by #ifdef/#else
280 // directives that are in effect currently is called preprocessing
281 // control stack. It is represented as a vector of PreprocessorControlDesc's.
282 //
283 // The control stack is updated according to the following rules:
284 //
285 // For each #ifdef we add an element to the control stack.
286 // For each #else we replace the top element with a descriptor
287 // with an inverted IsDefined value.
288 // For each #endif we pop the top element from the control stack.
289 //
290 // When CurPtr reaches the current buffer's end, the control stack
291 // must be empty, i.e. #ifdef and the corresponding #endif
292 // must be located in the same file.
293 struct PreprocessorControlDesc {
294 // Either tgtok::Ifdef or tgtok::Else.
295 tgtok::TokKind Kind;
296
297 // True, if the condition for this directive is true, false - otherwise.
298 // Examples:
299 // #ifdef NAME : true, if NAME is defined, false - otherwise.
300 // ...
301 // #else : false, if NAME is defined, true - otherwise.
302 bool IsDefined;
303
304 // Pointer into CurBuf to the beginning of the preprocessing directive
305 // word, e.g.:
306 // #ifdef NAME
307 // ^ - SrcPos
308 SMLoc SrcPos;
309 };
310
311 // We want to disallow code like this:
312 // file1.td:
313 // #define NAME
314 // #ifdef NAME
315 // include "file2.td"
316 // EOF
317 // file2.td:
318 // #endif
319 // EOF
320 //
321 // To do this, we clear the preprocessing control stack on entry
322 // to each of the included file. PrepIncludeStack is used to store
323 // preprocessing control stacks for the current file and all its
324 // parent files. The back() element is the preprocessing control
325 // stack for the current file.
326 std::vector<std::unique_ptr<std::vector<PreprocessorControlDesc>>>
327 PrepIncludeStack;
328
329 // Validate that the current preprocessing control stack is empty,
330 // since we are about to exit a file, and pop the include stack.
331 //
332 // If IncludeStackMustBeEmpty is true, the include stack must be empty
333 // after the popping, otherwise, the include stack must not be empty
334 // after the popping. Basically, the include stack must be empty
335 // only if we exit the "top-level" file (i.e. finish lexing).
336 //
337 // The method returns false, if the current preprocessing control stack
338 // is not empty (e.g. there is an unterminated #ifdef/#else),
339 // true - otherwise.
340 bool prepExitInclude(bool IncludeStackMustBeEmpty);
341
342 // Look ahead for a preprocessing directive starting from CurPtr. The caller
343 // must only call this method, if *(CurPtr - 1) is '#'. If the method matches
344 // a preprocessing directive word followed by a whitespace, then it returns
345 // one of the internal token kinds, i.e. Ifdef, Else, Endif, Define.
346 //
347 // CurPtr is not adjusted by this method.
348 tgtok::TokKind prepIsDirective() const;
349
350 // Given a preprocessing token kind, adjusts CurPtr to the end
351 // of the preprocessing directive word. Returns true, unless
352 // an unsupported token kind is passed in.
353 //
354 // We use look-ahead prepIsDirective() and prepEatPreprocessorDirective()
355 // to avoid adjusting CurPtr before we are sure that '#' is followed
356 // by a preprocessing directive. If it is not, then we fall back to
357 // tgtok::paste interpretation of '#'.
358 bool prepEatPreprocessorDirective(tgtok::TokKind Kind);
359
360 // The main "exit" point from the token parsing to preprocessor.
361 //
362 // The method is called for CurPtr, when prepIsDirective() returns
363 // true. The first parameter matches the result of prepIsDirective(),
364 // denoting the actual preprocessor directive to be processed.
365 //
366 // If the preprocessing directive disables the tokens processing, e.g.:
367 // #ifdef NAME // NAME is undefined
368 // then lexPreprocessor() enters the lines-skipping mode.
369 // In this mode, it does not parse any tokens, because the code under
370 // the #ifdef may not even be a correct tablegen code. The preprocessor
371 // looks for lines containing other preprocessing directives, which
372 // may be prepended with whitespaces and C-style comments. If the line
373 // does not contain a preprocessing directive, it is skipped completely.
374 // Otherwise, the preprocessing directive is processed by recursively
375 // calling lexPreprocessor(). The processing of the encountered
376 // preprocessing directives includes updating preprocessing control stack
377 // and adding new macros into DefinedMacros set.
378 //
379 // The second parameter controls whether lexPreprocessor() is called from
380 // LexToken() (true) or recursively from lexPreprocessor() (false).
381 //
382 // If ReturnNextLiveToken is true, the method returns the next
383 // LEX token following the current directive or following the end
384 // of the disabled preprocessing region corresponding to this directive.
385 // If ReturnNextLiveToken is false, the method returns the first parameter,
386 // unless there were errors encountered in the disabled preprocessing
387 // region - in this case, it returns tgtok::Error.
388 tgtok::TokKind lexPreprocessor(tgtok::TokKind Kind,
389 bool ReturnNextLiveToken = true);
390
391 // Worker method for lexPreprocessor() to skip lines after some
392 // preprocessing directive up to the buffer end or to the directive
393 // that re-enables token processing. The method returns true
394 // upon processing the next directive that re-enables tokens
395 // processing. False is returned if an error was encountered.
396 //
397 // Note that prepSkipRegion() calls lexPreprocessor() to process
398 // encountered preprocessing directives. In this case, the second
399 // parameter to lexPreprocessor() is set to false. Being passed
400 // false ReturnNextLiveToken, lexPreprocessor() must never call
401 // prepSkipRegion(). We assert this by passing ReturnNextLiveToken
402 // to prepSkipRegion() and checking that it is never set to false.
403 bool prepSkipRegion(bool MustNeverBeFalse);
404
405 // Lex name of the macro after either #ifdef or #define. We could have used
406 // LexIdentifier(), but it has special handling of "include" word, which
407 // could result in awkward diagnostic errors. Consider:
408 // ----
409 // #ifdef include
410 // class ...
411 // ----
412 // LexIdentifier() will engage LexInclude(), which will complain about
413 // missing file with name "class". Instead, prepLexMacroName() will treat
414 // "include" as a normal macro name.
415 //
416 // On entry, CurPtr points to the end of a preprocessing directive word.
417 // The method allows for whitespaces between the preprocessing directive
418 // and the macro name. The allowed whitespaces are ' ' and '\t'.
419 //
420 // If the first non-whitespace symbol after the preprocessing directive
421 // is a valid start symbol for an identifier (i.e. [a-zA-Z_]), then
422 // the method updates TokStart to the position of the first non-whitespace
423 // symbol, sets CurPtr to the position of the macro name's last symbol,
424 // and returns a string reference to the macro name. Otherwise,
425 // TokStart is set to the first non-whitespace symbol after the preprocessing
426 // directive, and the method returns an empty string reference.
427 //
428 // In all cases, TokStart may be used to point to the word following
429 // the preprocessing directive.
430 StringRef prepLexMacroName();
431
432 // Skip any whitespaces starting from CurPtr. The method is used
433 // only in the lines-skipping mode to find the first non-whitespace
434 // symbol after or at CurPtr. Allowed whitespaces are ' ', '\t', '\n'
435 // and '\r'. The method skips C-style comments as well, because
436 // it is used to find the beginning of the preprocessing directive.
437 // If we do not handle C-style comments the following code would
438 // result in incorrect detection of a preprocessing directive:
439 // /*
440 // #ifdef NAME
441 // */
442 // As long as we skip C-style comments, the following code is correctly
443 // recognized as a preprocessing directive:
444 // /* first line comment
445 // second line comment */ #ifdef NAME
446 //
447 // The method returns true upon reaching the first non-whitespace symbol
448 // or EOF, CurPtr is set to point to this symbol. The method returns false,
449 // if an error occurred during skipping of a C-style comment.
450 bool prepSkipLineBegin();
451
452 // Skip any whitespaces or comments after a preprocessing directive.
453 // The method returns true upon reaching either end of the line
454 // or end of the file. If there is a multiline C-style comment
455 // after the preprocessing directive, the method skips
456 // the comment, so the final CurPtr may point to one of the next lines.
457 // The method returns false, if an error occurred during skipping
458 // C- or C++-style comment, or a non-whitespace symbol appears
459 // after the preprocessing directive.
460 //
461 // The method maybe called both during lines-skipping and tokens
462 // processing. It actually verifies that only whitespaces or/and
463 // comments follow a preprocessing directive.
464 //
465 // After the execution of this mehod, CurPtr points either to new line
466 // symbol, buffer end or non-whitespace symbol following the preprocesing
467 // directive.
468 bool prepSkipDirectiveEnd();
469
470 // Return true, if the current preprocessor control stack is such that
471 // we should allow lexer to process the next token, false - otherwise.
472 //
473 // In particular, the method returns true, if all the #ifdef/#else
474 // controls on the stack have their IsDefined member set to true.
475 bool prepIsProcessingEnabled();
476
477 // Report an error, if we reach EOF with non-empty preprocessing control
478 // stack. This means there is no matching #endif for the previous
479 // #ifdef/#else.
480 void prepReportPreprocessorStackError();
481};
482
483} // end namespace llvm
484
485#endif
486