1//===- TokenLexer.cpp - Lex from a token stream ---------------------------===//
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 file implements the TokenLexer interface.
10//
11//===----------------------------------------------------------------------===//
12
13#include "clang/Lex/TokenLexer.h"
14#include "clang/Basic/Diagnostic.h"
15#include "clang/Basic/IdentifierTable.h"
16#include "clang/Basic/LangOptions.h"
17#include "clang/Basic/SourceLocation.h"
18#include "clang/Basic/SourceManager.h"
19#include "clang/Basic/TokenKinds.h"
20#include "clang/Lex/LexDiagnostic.h"
21#include "clang/Lex/Lexer.h"
22#include "clang/Lex/MacroArgs.h"
23#include "clang/Lex/MacroInfo.h"
24#include "clang/Lex/Preprocessor.h"
25#include "clang/Lex/Token.h"
26#include "clang/Lex/VariadicMacroSupport.h"
27#include "llvm/ADT/ArrayRef.h"
28#include "llvm/ADT/STLExtras.h"
29#include "llvm/ADT/SmallVector.h"
30#include "llvm/ADT/iterator_range.h"
31#include <cassert>
32#include <cstring>
33#include <optional>
34
35using namespace clang;
36
37/// Create a TokenLexer for the specified macro with the specified actual
38/// arguments. Note that this ctor takes ownership of the ActualArgs pointer.
39void TokenLexer::Init(Token &Tok, SourceLocation ELEnd, MacroInfo *MI,
40 MacroArgs *Actuals) {
41 // If the client is reusing a TokenLexer, make sure to free any memory
42 // associated with it.
43 destroy();
44
45 Macro = MI;
46 ActualArgs = Actuals;
47 CurTokenIdx = 0;
48
49 ExpandLocStart = Tok.getLocation();
50 ExpandLocEnd = ELEnd;
51 AtStartOfLine = Tok.isAtStartOfLine();
52 HasLeadingSpace = Tok.hasLeadingSpace();
53 NextTokGetsSpace = false;
54 Tokens = &*Macro->tokens_begin();
55 OwnsTokens = false;
56 DisableMacroExpansion = false;
57 IsReinject = false;
58 NumTokens = Macro->tokens_end()-Macro->tokens_begin();
59 MacroExpansionStart = SourceLocation();
60
61 SourceManager &SM = PP.getSourceManager();
62 MacroStartSLocOffset = SM.getNextLocalOffset();
63
64 if (NumTokens > 0) {
65 assert(Tokens[0].getLocation().isValid());
66 assert((Tokens[0].getLocation().isFileID() || Tokens[0].is(tok::comment)) &&
67 "Macro defined in macro?");
68 assert(ExpandLocStart.isValid());
69
70 // Reserve a source location entry chunk for the length of the macro
71 // definition. Tokens that get lexed directly from the definition will
72 // have their locations pointing inside this chunk. This is to avoid
73 // creating separate source location entries for each token.
74 MacroDefStart = SM.getExpansionLoc(Loc: Tokens[0].getLocation());
75 MacroDefLength = Macro->getDefinitionLength(SM);
76 MacroExpansionStart = SM.createExpansionLoc(SpellingLoc: MacroDefStart,
77 ExpansionLocStart: ExpandLocStart,
78 ExpansionLocEnd: ExpandLocEnd,
79 Length: MacroDefLength);
80 }
81
82 // If this is a function-like macro, expand the arguments and change
83 // Tokens to point to the expanded tokens.
84 if (Macro->isFunctionLike() && Macro->getNumParams())
85 ExpandFunctionArguments();
86
87 // Mark the macro as currently disabled, so that it is not recursively
88 // expanded. The macro must be disabled only after argument pre-expansion of
89 // function-like macro arguments occurs.
90 Macro->DisableMacro();
91}
92
93/// Create a TokenLexer for the specified token stream. This does not
94/// take ownership of the specified token vector.
95void TokenLexer::Init(const Token *TokArray, unsigned NumToks,
96 bool disableMacroExpansion, bool ownsTokens,
97 bool isReinject) {
98 assert(!isReinject || disableMacroExpansion);
99 // If the client is reusing a TokenLexer, make sure to free any memory
100 // associated with it.
101 destroy();
102
103 Macro = nullptr;
104 ActualArgs = nullptr;
105 Tokens = TokArray;
106 OwnsTokens = ownsTokens;
107 DisableMacroExpansion = disableMacroExpansion;
108 IsReinject = isReinject;
109 NumTokens = NumToks;
110 CurTokenIdx = 0;
111 ExpandLocStart = ExpandLocEnd = SourceLocation();
112 AtStartOfLine = false;
113 HasLeadingSpace = false;
114 NextTokGetsSpace = false;
115 MacroExpansionStart = SourceLocation();
116
117 // Set HasLeadingSpace/AtStartOfLine so that the first token will be
118 // returned unmodified.
119 if (NumToks != 0) {
120 AtStartOfLine = TokArray[0].isAtStartOfLine();
121 HasLeadingSpace = TokArray[0].hasLeadingSpace();
122 }
123}
124
125void TokenLexer::destroy() {
126 // If this was a function-like macro that actually uses its arguments, delete
127 // the expanded tokens.
128 if (OwnsTokens) {
129 delete [] Tokens;
130 Tokens = nullptr;
131 OwnsTokens = false;
132 }
133
134 // TokenLexer owns its formal arguments.
135 if (ActualArgs) ActualArgs->destroy(PP);
136}
137
138bool TokenLexer::MaybeRemoveCommaBeforeVaArgs(
139 SmallVectorImpl<Token> &ResultToks, bool HasPasteOperator, MacroInfo *Macro,
140 unsigned MacroArgNo, Preprocessor &PP) {
141 // Is the macro argument __VA_ARGS__?
142 if (!Macro->isVariadic() || MacroArgNo != Macro->getNumParams()-1)
143 return false;
144
145 // In Microsoft-compatibility mode, a comma is removed in the expansion
146 // of " ... , __VA_ARGS__ " if __VA_ARGS__ is empty. This extension is
147 // not supported by gcc.
148 if (!HasPasteOperator && !PP.getLangOpts().MSVCCompat)
149 return false;
150
151 // GCC removes the comma in the expansion of " ... , ## __VA_ARGS__ " if
152 // __VA_ARGS__ is empty, but not in strict C99 mode where there are no
153 // named arguments, where it remains. In all other modes, including C99
154 // with GNU extensions, it is removed regardless of named arguments.
155 // Microsoft also appears to support this extension, unofficially.
156 if (PP.getLangOpts().C99 && !PP.getLangOpts().GNUMode
157 && Macro->getNumParams() < 2)
158 return false;
159
160 // Is a comma available to be removed?
161 if (ResultToks.empty() || !ResultToks.back().is(K: tok::comma))
162 return false;
163
164 // Issue an extension diagnostic for the paste operator.
165 if (HasPasteOperator)
166 PP.Diag(ResultToks.back().getLocation(), diag::ext_paste_comma);
167
168 // Remove the comma.
169 ResultToks.pop_back();
170
171 if (!ResultToks.empty()) {
172 // If the comma was right after another paste (e.g. "X##,##__VA_ARGS__"),
173 // then removal of the comma should produce a placemarker token (in C99
174 // terms) which we model by popping off the previous ##, giving us a plain
175 // "X" when __VA_ARGS__ is empty.
176 if (ResultToks.back().is(K: tok::hashhash))
177 ResultToks.pop_back();
178
179 // Remember that this comma was elided.
180 ResultToks.back().setFlag(Token::CommaAfterElided);
181 }
182
183 // Never add a space, even if the comma, ##, or arg had a space.
184 NextTokGetsSpace = false;
185 return true;
186}
187
188void TokenLexer::stringifyVAOPTContents(
189 SmallVectorImpl<Token> &ResultToks, const VAOptExpansionContext &VCtx,
190 const SourceLocation VAOPTClosingParenLoc) {
191 const int NumToksPriorToVAOpt = VCtx.getNumberOfTokensPriorToVAOpt();
192 const unsigned int NumVAOptTokens = ResultToks.size() - NumToksPriorToVAOpt;
193 Token *const VAOPTTokens =
194 NumVAOptTokens ? &ResultToks[NumToksPriorToVAOpt] : nullptr;
195
196 SmallVector<Token, 64> ConcatenatedVAOPTResultToks;
197 // FIXME: Should we keep track within VCtx that we did or didnot
198 // encounter pasting - and only then perform this loop.
199
200 // Perform token pasting (concatenation) prior to stringization.
201 for (unsigned int CurTokenIdx = 0; CurTokenIdx != NumVAOptTokens;
202 ++CurTokenIdx) {
203 if (VAOPTTokens[CurTokenIdx].is(K: tok::hashhash)) {
204 assert(CurTokenIdx != 0 &&
205 "Can not have __VAOPT__ contents begin with a ##");
206 Token &LHS = VAOPTTokens[CurTokenIdx - 1];
207 pasteTokens(LHSTok&: LHS, TokenStream: llvm::ArrayRef(VAOPTTokens, NumVAOptTokens),
208 CurIdx&: CurTokenIdx);
209 // Replace the token prior to the first ## in this iteration.
210 ConcatenatedVAOPTResultToks.back() = LHS;
211 if (CurTokenIdx == NumVAOptTokens)
212 break;
213 }
214 ConcatenatedVAOPTResultToks.push_back(Elt: VAOPTTokens[CurTokenIdx]);
215 }
216
217 ConcatenatedVAOPTResultToks.push_back(Elt: VCtx.getEOFTok());
218 // Get the SourceLocation that represents the start location within
219 // the macro definition that marks where this string is substituted
220 // into: i.e. the __VA_OPT__ and the ')' within the spelling of the
221 // macro definition, and use it to indicate that the stringified token
222 // was generated from that location.
223 const SourceLocation ExpansionLocStartWithinMacro =
224 getExpansionLocForMacroDefLoc(loc: VCtx.getVAOptLoc());
225 const SourceLocation ExpansionLocEndWithinMacro =
226 getExpansionLocForMacroDefLoc(loc: VAOPTClosingParenLoc);
227
228 Token StringifiedVAOPT = MacroArgs::StringifyArgument(
229 ArgToks: &ConcatenatedVAOPTResultToks[0], PP, Charify: VCtx.hasCharifyBefore() /*Charify*/,
230 ExpansionLocStart: ExpansionLocStartWithinMacro, ExpansionLocEnd: ExpansionLocEndWithinMacro);
231
232 if (VCtx.getLeadingSpaceForStringifiedToken())
233 StringifiedVAOPT.setFlag(Token::LeadingSpace);
234
235 StringifiedVAOPT.setFlag(Token::StringifiedInMacro);
236 // Resize (shrink) the token stream to just capture this stringified token.
237 ResultToks.resize(N: NumToksPriorToVAOpt + 1);
238 ResultToks.back() = StringifiedVAOPT;
239}
240
241/// Expand the arguments of a function-like macro so that we can quickly
242/// return preexpanded tokens from Tokens.
243void TokenLexer::ExpandFunctionArguments() {
244 SmallVector<Token, 128> ResultToks;
245
246 // Loop through 'Tokens', expanding them into ResultToks. Keep
247 // track of whether we change anything. If not, no need to keep them. If so,
248 // we install the newly expanded sequence as the new 'Tokens' list.
249 bool MadeChange = false;
250
251 std::optional<bool> CalledWithVariadicArguments;
252
253 VAOptExpansionContext VCtx(PP);
254
255 for (unsigned I = 0, E = NumTokens; I != E; ++I) {
256 const Token &CurTok = Tokens[I];
257 // We don't want a space for the next token after a paste
258 // operator. In valid code, the token will get smooshed onto the
259 // preceding one anyway. In assembler-with-cpp mode, invalid
260 // pastes are allowed through: in this case, we do not want the
261 // extra whitespace to be added. For example, we want ". ## foo"
262 // -> ".foo" not ". foo".
263 if (I != 0 && !Tokens[I-1].is(K: tok::hashhash) && CurTok.hasLeadingSpace())
264 NextTokGetsSpace = true;
265
266 if (VCtx.isVAOptToken(T: CurTok)) {
267 MadeChange = true;
268 assert(Tokens[I + 1].is(tok::l_paren) &&
269 "__VA_OPT__ must be followed by '('");
270
271 ++I; // Skip the l_paren
272 VCtx.sawVAOptFollowedByOpeningParens(VAOptLoc: CurTok.getLocation(),
273 NumPriorTokens: ResultToks.size());
274
275 continue;
276 }
277
278 // We have entered into the __VA_OPT__ context, so handle tokens
279 // appropriately.
280 if (VCtx.isInVAOpt()) {
281 // If we are about to process a token that is either an argument to
282 // __VA_OPT__ or its closing rparen, then:
283 // 1) If the token is the closing rparen that exits us out of __VA_OPT__,
284 // perform any necessary stringification or placemarker processing,
285 // and/or skip to the next token.
286 // 2) else if macro was invoked without variadic arguments skip this
287 // token.
288 // 3) else (macro was invoked with variadic arguments) process the token
289 // normally.
290
291 if (Tokens[I].is(K: tok::l_paren))
292 VCtx.sawOpeningParen(LParenLoc: Tokens[I].getLocation());
293 // Continue skipping tokens within __VA_OPT__ if the macro was not
294 // called with variadic arguments, else let the rest of the loop handle
295 // this token. Note sawClosingParen() returns true only if the r_paren matches
296 // the closing r_paren of the __VA_OPT__.
297 if (!Tokens[I].is(K: tok::r_paren) || !VCtx.sawClosingParen()) {
298 // Lazily expand __VA_ARGS__ when we see the first __VA_OPT__.
299 if (!CalledWithVariadicArguments) {
300 CalledWithVariadicArguments =
301 ActualArgs->invokedWithVariadicArgument(MI: Macro, PP);
302 }
303 if (!*CalledWithVariadicArguments) {
304 // Skip this token.
305 continue;
306 }
307 // ... else the macro was called with variadic arguments, and we do not
308 // have a closing rparen - so process this token normally.
309 } else {
310 // Current token is the closing r_paren which marks the end of the
311 // __VA_OPT__ invocation, so handle any place-marker pasting (if
312 // empty) by removing hashhash either before (if exists) or after. And
313 // also stringify the entire contents if VAOPT was preceded by a hash,
314 // but do so only after any token concatenation that needs to occur
315 // within the contents of VAOPT.
316
317 if (VCtx.hasStringifyOrCharifyBefore()) {
318 // Replace all the tokens just added from within VAOPT into a single
319 // stringified token. This requires token-pasting to eagerly occur
320 // within these tokens. If either the contents of VAOPT were empty
321 // or the macro wasn't called with any variadic arguments, the result
322 // is a token that represents an empty string.
323 stringifyVAOPTContents(ResultToks, VCtx,
324 /*ClosingParenLoc*/ VAOPTClosingParenLoc: Tokens[I].getLocation());
325
326 } else if (/*No tokens within VAOPT*/
327 ResultToks.size() == VCtx.getNumberOfTokensPriorToVAOpt()) {
328 // Treat VAOPT as a placemarker token. Eat either the '##' before the
329 // RHS/VAOPT (if one exists, suggesting that the LHS (if any) to that
330 // hashhash was not a placemarker) or the '##'
331 // after VAOPT, but not both.
332
333 if (ResultToks.size() && ResultToks.back().is(K: tok::hashhash)) {
334 ResultToks.pop_back();
335 } else if ((I + 1 != E) && Tokens[I + 1].is(K: tok::hashhash)) {
336 ++I; // Skip the following hashhash.
337 }
338 } else {
339 // If there's a ## before the __VA_OPT__, we might have discovered
340 // that the __VA_OPT__ begins with a placeholder. We delay action on
341 // that to now to avoid messing up our stashed count of tokens before
342 // __VA_OPT__.
343 if (VCtx.beginsWithPlaceholder()) {
344 assert(VCtx.getNumberOfTokensPriorToVAOpt() > 0 &&
345 ResultToks.size() >= VCtx.getNumberOfTokensPriorToVAOpt() &&
346 ResultToks[VCtx.getNumberOfTokensPriorToVAOpt() - 1].is(
347 tok::hashhash) &&
348 "no token paste before __VA_OPT__");
349 ResultToks.erase(CI: ResultToks.begin() +
350 VCtx.getNumberOfTokensPriorToVAOpt() - 1);
351 }
352 // If the expansion of __VA_OPT__ ends with a placeholder, eat any
353 // following '##' token.
354 if (VCtx.endsWithPlaceholder() && I + 1 != E &&
355 Tokens[I + 1].is(K: tok::hashhash)) {
356 ++I;
357 }
358 }
359 VCtx.reset();
360 // We processed __VA_OPT__'s closing paren (and the exit out of
361 // __VA_OPT__), so skip to the next token.
362 continue;
363 }
364 }
365
366 // If we found the stringify operator, get the argument stringified. The
367 // preprocessor already verified that the following token is a macro
368 // parameter or __VA_OPT__ when the #define was lexed.
369
370 if (CurTok.isOneOf(K1: tok::hash, K2: tok::hashat)) {
371 int ArgNo = Macro->getParameterNum(Arg: Tokens[I+1].getIdentifierInfo());
372 assert((ArgNo != -1 || VCtx.isVAOptToken(Tokens[I + 1])) &&
373 "Token following # is not an argument or __VA_OPT__!");
374
375 if (ArgNo == -1) {
376 // Handle the __VA_OPT__ case.
377 VCtx.sawHashOrHashAtBefore(HasLeadingSpace: NextTokGetsSpace,
378 IsHashAt: CurTok.is(K: tok::hashat));
379 continue;
380 }
381 // Else handle the simple argument case.
382 SourceLocation ExpansionLocStart =
383 getExpansionLocForMacroDefLoc(loc: CurTok.getLocation());
384 SourceLocation ExpansionLocEnd =
385 getExpansionLocForMacroDefLoc(loc: Tokens[I+1].getLocation());
386
387 bool Charify = CurTok.is(K: tok::hashat);
388 const Token *UnexpArg = ActualArgs->getUnexpArgument(Arg: ArgNo);
389 Token Res = MacroArgs::StringifyArgument(
390 ArgToks: UnexpArg, PP, Charify, ExpansionLocStart, ExpansionLocEnd);
391 Res.setFlag(Token::StringifiedInMacro);
392
393 // The stringified/charified string leading space flag gets set to match
394 // the #/#@ operator.
395 if (NextTokGetsSpace)
396 Res.setFlag(Token::LeadingSpace);
397
398 ResultToks.push_back(Elt: Res);
399 MadeChange = true;
400 ++I; // Skip arg name.
401 NextTokGetsSpace = false;
402 continue;
403 }
404
405 // Find out if there is a paste (##) operator before or after the token.
406 bool NonEmptyPasteBefore =
407 !ResultToks.empty() && ResultToks.back().is(K: tok::hashhash);
408 bool PasteBefore = I != 0 && Tokens[I-1].is(K: tok::hashhash);
409 bool PasteAfter = I+1 != E && Tokens[I+1].is(K: tok::hashhash);
410 bool RParenAfter = I+1 != E && Tokens[I+1].is(K: tok::r_paren);
411
412 assert((!NonEmptyPasteBefore || PasteBefore || VCtx.isInVAOpt()) &&
413 "unexpected ## in ResultToks");
414
415 // Otherwise, if this is not an argument token, just add the token to the
416 // output buffer.
417 IdentifierInfo *II = CurTok.getIdentifierInfo();
418 int ArgNo = II ? Macro->getParameterNum(Arg: II) : -1;
419 if (ArgNo == -1) {
420 // This isn't an argument, just add it.
421 ResultToks.push_back(Elt: CurTok);
422
423 if (NextTokGetsSpace) {
424 ResultToks.back().setFlag(Token::LeadingSpace);
425 NextTokGetsSpace = false;
426 } else if (PasteBefore && !NonEmptyPasteBefore)
427 ResultToks.back().clearFlag(Flag: Token::LeadingSpace);
428
429 continue;
430 }
431
432 // An argument is expanded somehow, the result is different than the
433 // input.
434 MadeChange = true;
435
436 // Otherwise, this is a use of the argument.
437
438 // In Microsoft mode, remove the comma before __VA_ARGS__ to ensure there
439 // are no trailing commas if __VA_ARGS__ is empty.
440 if (!PasteBefore && ActualArgs->isVarargsElidedUse() &&
441 MaybeRemoveCommaBeforeVaArgs(ResultToks,
442 /*HasPasteOperator=*/false,
443 Macro, MacroArgNo: ArgNo, PP))
444 continue;
445
446 // If it is not the LHS/RHS of a ## operator, we must pre-expand the
447 // argument and substitute the expanded tokens into the result. This is
448 // C99 6.10.3.1p1.
449 if (!PasteBefore && !PasteAfter) {
450 const Token *ResultArgToks;
451
452 // Only preexpand the argument if it could possibly need it. This
453 // avoids some work in common cases.
454 const Token *ArgTok = ActualArgs->getUnexpArgument(Arg: ArgNo);
455 if (ActualArgs->ArgNeedsPreexpansion(ArgTok, PP))
456 ResultArgToks = &ActualArgs->getPreExpArgument(Arg: ArgNo, PP)[0];
457 else
458 ResultArgToks = ArgTok; // Use non-preexpanded tokens.
459
460 // If the arg token expanded into anything, append it.
461 if (ResultArgToks->isNot(K: tok::eof)) {
462 size_t FirstResult = ResultToks.size();
463 unsigned NumToks = MacroArgs::getArgLength(ArgPtr: ResultArgToks);
464 ResultToks.append(in_start: ResultArgToks, in_end: ResultArgToks+NumToks);
465
466 // In Microsoft-compatibility mode, we follow MSVC's preprocessing
467 // behavior by not considering single commas from nested macro
468 // expansions as argument separators. Set a flag on the token so we can
469 // test for this later when the macro expansion is processed.
470 if (PP.getLangOpts().MSVCCompat && NumToks == 1 &&
471 ResultToks.back().is(K: tok::comma))
472 ResultToks.back().setFlag(Token::IgnoredComma);
473
474 // If the '##' came from expanding an argument, turn it into 'unknown'
475 // to avoid pasting.
476 for (Token &Tok : llvm::drop_begin(RangeOrContainer&: ResultToks, N: FirstResult))
477 if (Tok.is(K: tok::hashhash))
478 Tok.setKind(tok::unknown);
479
480 if(ExpandLocStart.isValid()) {
481 updateLocForMacroArgTokens(ArgIdSpellLoc: CurTok.getLocation(),
482 begin_tokens: ResultToks.begin()+FirstResult,
483 end_tokens: ResultToks.end());
484 }
485
486 // If any tokens were substituted from the argument, the whitespace
487 // before the first token should match the whitespace of the arg
488 // identifier.
489 ResultToks[FirstResult].setFlagValue(Flag: Token::LeadingSpace,
490 Val: NextTokGetsSpace);
491 ResultToks[FirstResult].setFlagValue(Flag: Token::StartOfLine, Val: false);
492 NextTokGetsSpace = false;
493 } else {
494 // We're creating a placeholder token. Usually this doesn't matter,
495 // but it can affect paste behavior when at the start or end of a
496 // __VA_OPT__.
497 if (NonEmptyPasteBefore) {
498 // We're imagining a placeholder token is inserted here. If this is
499 // the first token in a __VA_OPT__ after a ##, delete the ##.
500 assert(VCtx.isInVAOpt() && "should only happen inside a __VA_OPT__");
501 VCtx.hasPlaceholderAfterHashhashAtStart();
502 } else if (RParenAfter)
503 VCtx.hasPlaceholderBeforeRParen();
504 }
505 continue;
506 }
507
508 // Okay, we have a token that is either the LHS or RHS of a paste (##)
509 // argument. It gets substituted as its non-pre-expanded tokens.
510 const Token *ArgToks = ActualArgs->getUnexpArgument(Arg: ArgNo);
511 unsigned NumToks = MacroArgs::getArgLength(ArgPtr: ArgToks);
512 if (NumToks) { // Not an empty argument?
513 bool VaArgsPseudoPaste = false;
514 // If this is the GNU ", ## __VA_ARGS__" extension, and we just learned
515 // that __VA_ARGS__ expands to multiple tokens, avoid a pasting error when
516 // the expander tries to paste ',' with the first token of the __VA_ARGS__
517 // expansion.
518 if (NonEmptyPasteBefore && ResultToks.size() >= 2 &&
519 ResultToks[ResultToks.size()-2].is(K: tok::comma) &&
520 (unsigned)ArgNo == Macro->getNumParams()-1 &&
521 Macro->isVariadic()) {
522 VaArgsPseudoPaste = true;
523 // Remove the paste operator, report use of the extension.
524 PP.Diag(ResultToks.pop_back_val().getLocation(), diag::ext_paste_comma);
525 }
526
527 ResultToks.append(in_start: ArgToks, in_end: ArgToks+NumToks);
528
529 // If the '##' came from expanding an argument, turn it into 'unknown'
530 // to avoid pasting.
531 for (Token &Tok : llvm::make_range(x: ResultToks.end() - NumToks,
532 y: ResultToks.end())) {
533 if (Tok.is(K: tok::hashhash))
534 Tok.setKind(tok::unknown);
535 }
536
537 if (ExpandLocStart.isValid()) {
538 updateLocForMacroArgTokens(ArgIdSpellLoc: CurTok.getLocation(),
539 begin_tokens: ResultToks.end()-NumToks, end_tokens: ResultToks.end());
540 }
541
542 // Transfer the leading whitespace information from the token
543 // (the macro argument) onto the first token of the
544 // expansion. Note that we don't do this for the GNU
545 // pseudo-paste extension ", ## __VA_ARGS__".
546 if (!VaArgsPseudoPaste) {
547 ResultToks[ResultToks.size() - NumToks].setFlagValue(Flag: Token::StartOfLine,
548 Val: false);
549 ResultToks[ResultToks.size() - NumToks].setFlagValue(
550 Flag: Token::LeadingSpace, Val: NextTokGetsSpace);
551 }
552
553 NextTokGetsSpace = false;
554 continue;
555 }
556
557 // If an empty argument is on the LHS or RHS of a paste, the standard (C99
558 // 6.10.3.3p2,3) calls for a bunch of placemarker stuff to occur. We
559 // implement this by eating ## operators when a LHS or RHS expands to
560 // empty.
561 if (PasteAfter) {
562 // Discard the argument token and skip (don't copy to the expansion
563 // buffer) the paste operator after it.
564 ++I;
565 continue;
566 }
567
568 if (RParenAfter && !NonEmptyPasteBefore)
569 VCtx.hasPlaceholderBeforeRParen();
570
571 // If this is on the RHS of a paste operator, we've already copied the
572 // paste operator to the ResultToks list, unless the LHS was empty too.
573 // Remove it.
574 assert(PasteBefore);
575 if (NonEmptyPasteBefore) {
576 assert(ResultToks.back().is(tok::hashhash));
577 // Do not remove the paste operator if it is the one before __VA_OPT__
578 // (and we are still processing tokens within VA_OPT). We handle the case
579 // of removing the paste operator if __VA_OPT__ reduces to the notional
580 // placemarker above when we encounter the closing paren of VA_OPT.
581 if (!VCtx.isInVAOpt() ||
582 ResultToks.size() > VCtx.getNumberOfTokensPriorToVAOpt())
583 ResultToks.pop_back();
584 else
585 VCtx.hasPlaceholderAfterHashhashAtStart();
586 }
587
588 // If this is the __VA_ARGS__ token, and if the argument wasn't provided,
589 // and if the macro had at least one real argument, and if the token before
590 // the ## was a comma, remove the comma. This is a GCC extension which is
591 // disabled when using -std=c99.
592 if (ActualArgs->isVarargsElidedUse())
593 MaybeRemoveCommaBeforeVaArgs(ResultToks,
594 /*HasPasteOperator=*/true,
595 Macro, MacroArgNo: ArgNo, PP);
596 }
597
598 // If anything changed, install this as the new Tokens list.
599 if (MadeChange) {
600 assert(!OwnsTokens && "This would leak if we already own the token list");
601 // This is deleted in the dtor.
602 NumTokens = ResultToks.size();
603 // The tokens will be added to Preprocessor's cache and will be removed
604 // when this TokenLexer finishes lexing them.
605 Tokens = PP.cacheMacroExpandedTokens(tokLexer: this, tokens: ResultToks);
606
607 // The preprocessor cache of macro expanded tokens owns these tokens,not us.
608 OwnsTokens = false;
609 }
610}
611
612/// Checks if two tokens form wide string literal.
613static bool isWideStringLiteralFromMacro(const Token &FirstTok,
614 const Token &SecondTok) {
615 return FirstTok.is(K: tok::identifier) &&
616 FirstTok.getIdentifierInfo()->isStr(Str: "L") && SecondTok.isLiteral() &&
617 SecondTok.stringifiedInMacro();
618}
619
620/// Lex - Lex and return a token from this macro stream.
621bool TokenLexer::Lex(Token &Tok) {
622 // Lexing off the end of the macro, pop this macro off the expansion stack.
623 if (isAtEnd()) {
624 // If this is a macro (not a token stream), mark the macro enabled now
625 // that it is no longer being expanded.
626 if (Macro) Macro->EnableMacro();
627
628 Tok.startToken();
629 Tok.setFlagValue(Flag: Token::StartOfLine , Val: AtStartOfLine);
630 Tok.setFlagValue(Flag: Token::LeadingSpace, Val: HasLeadingSpace || NextTokGetsSpace);
631 if (CurTokenIdx == 0)
632 Tok.setFlag(Token::LeadingEmptyMacro);
633 return PP.HandleEndOfTokenLexer(Result&: Tok);
634 }
635
636 SourceManager &SM = PP.getSourceManager();
637
638 // If this is the first token of the expanded result, we inherit spacing
639 // properties later.
640 bool isFirstToken = CurTokenIdx == 0;
641
642 // Get the next token to return.
643 Tok = Tokens[CurTokenIdx++];
644 if (IsReinject)
645 Tok.setFlag(Token::IsReinjected);
646
647 bool TokenIsFromPaste = false;
648
649 // If this token is followed by a token paste (##) operator, paste the tokens!
650 // Note that ## is a normal token when not expanding a macro.
651 if (!isAtEnd() && Macro &&
652 (Tokens[CurTokenIdx].is(K: tok::hashhash) ||
653 // Special processing of L#x macros in -fms-compatibility mode.
654 // Microsoft compiler is able to form a wide string literal from
655 // 'L#macro_arg' construct in a function-like macro.
656 (PP.getLangOpts().MSVCCompat &&
657 isWideStringLiteralFromMacro(FirstTok: Tok, SecondTok: Tokens[CurTokenIdx])))) {
658 // When handling the microsoft /##/ extension, the final token is
659 // returned by pasteTokens, not the pasted token.
660 if (pasteTokens(Tok))
661 return true;
662
663 TokenIsFromPaste = true;
664 }
665
666 // The token's current location indicate where the token was lexed from. We
667 // need this information to compute the spelling of the token, but any
668 // diagnostics for the expanded token should appear as if they came from
669 // ExpansionLoc. Pull this information together into a new SourceLocation
670 // that captures all of this.
671 if (ExpandLocStart.isValid() && // Don't do this for token streams.
672 // Check that the token's location was not already set properly.
673 SM.isBeforeInSLocAddrSpace(LHS: Tok.getLocation(), RHS: MacroStartSLocOffset)) {
674 SourceLocation instLoc;
675 if (Tok.is(K: tok::comment)) {
676 instLoc = SM.createExpansionLoc(SpellingLoc: Tok.getLocation(),
677 ExpansionLocStart: ExpandLocStart,
678 ExpansionLocEnd: ExpandLocEnd,
679 Length: Tok.getLength());
680 } else {
681 instLoc = getExpansionLocForMacroDefLoc(loc: Tok.getLocation());
682 }
683
684 Tok.setLocation(instLoc);
685 }
686
687 // If this is the first token, set the lexical properties of the token to
688 // match the lexical properties of the macro identifier.
689 if (isFirstToken) {
690 Tok.setFlagValue(Flag: Token::StartOfLine , Val: AtStartOfLine);
691 Tok.setFlagValue(Flag: Token::LeadingSpace, Val: HasLeadingSpace);
692 } else {
693 // If this is not the first token, we may still need to pass through
694 // leading whitespace if we've expanded a macro.
695 if (AtStartOfLine) Tok.setFlag(Token::StartOfLine);
696 if (HasLeadingSpace) Tok.setFlag(Token::LeadingSpace);
697 }
698 AtStartOfLine = false;
699 HasLeadingSpace = false;
700
701 // Handle recursive expansion!
702 if (!Tok.isAnnotation() && Tok.getIdentifierInfo() != nullptr) {
703 // Change the kind of this identifier to the appropriate token kind, e.g.
704 // turning "for" into a keyword.
705 IdentifierInfo *II = Tok.getIdentifierInfo();
706 Tok.setKind(II->getTokenID());
707
708 // If this identifier was poisoned and from a paste, emit an error. This
709 // won't be handled by Preprocessor::HandleIdentifier because this is coming
710 // from a macro expansion.
711 if (II->isPoisoned() && TokenIsFromPaste) {
712 PP.HandlePoisonedIdentifier(Identifier&: Tok);
713 }
714
715 if (!DisableMacroExpansion && II->isHandleIdentifierCase())
716 return PP.HandleIdentifier(Identifier&: Tok);
717 }
718
719 // Otherwise, return a normal token.
720 return true;
721}
722
723bool TokenLexer::pasteTokens(Token &Tok) {
724 return pasteTokens(LHSTok&: Tok, TokenStream: llvm::ArrayRef(Tokens, NumTokens), CurIdx&: CurTokenIdx);
725}
726
727/// LHSTok is the LHS of a ## operator, and CurTokenIdx is the ##
728/// operator. Read the ## and RHS, and paste the LHS/RHS together. If there
729/// are more ## after it, chomp them iteratively. Return the result as LHSTok.
730/// If this returns true, the caller should immediately return the token.
731bool TokenLexer::pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream,
732 unsigned int &CurIdx) {
733 assert(CurIdx > 0 && "## can not be the first token within tokens");
734 assert((TokenStream[CurIdx].is(tok::hashhash) ||
735 (PP.getLangOpts().MSVCCompat &&
736 isWideStringLiteralFromMacro(LHSTok, TokenStream[CurIdx]))) &&
737 "Token at this Index must be ## or part of the MSVC 'L "
738 "#macro-arg' pasting pair");
739
740 // MSVC: If previous token was pasted, this must be a recovery from an invalid
741 // paste operation. Ignore spaces before this token to mimic MSVC output.
742 // Required for generating valid UUID strings in some MS headers.
743 if (PP.getLangOpts().MicrosoftExt && (CurIdx >= 2) &&
744 TokenStream[CurIdx - 2].is(K: tok::hashhash))
745 LHSTok.clearFlag(Flag: Token::LeadingSpace);
746
747 SmallString<128> Buffer;
748 const char *ResultTokStrPtr = nullptr;
749 SourceLocation StartLoc = LHSTok.getLocation();
750 SourceLocation PasteOpLoc;
751
752 auto IsAtEnd = [&TokenStream, &CurIdx] {
753 return TokenStream.size() == CurIdx;
754 };
755
756 do {
757 // Consume the ## operator if any.
758 PasteOpLoc = TokenStream[CurIdx].getLocation();
759 if (TokenStream[CurIdx].is(K: tok::hashhash))
760 ++CurIdx;
761 assert(!IsAtEnd() && "No token on the RHS of a paste operator!");
762
763 // Get the RHS token.
764 const Token &RHS = TokenStream[CurIdx];
765
766 // Allocate space for the result token. This is guaranteed to be enough for
767 // the two tokens.
768 Buffer.resize(N: LHSTok.getLength() + RHS.getLength());
769
770 // Get the spelling of the LHS token in Buffer.
771 const char *BufPtr = &Buffer[0];
772 bool Invalid = false;
773 unsigned LHSLen = PP.getSpelling(Tok: LHSTok, Buffer&: BufPtr, Invalid: &Invalid);
774 if (BufPtr != &Buffer[0]) // Really, we want the chars in Buffer!
775 memcpy(dest: &Buffer[0], src: BufPtr, n: LHSLen);
776 if (Invalid)
777 return true;
778
779 BufPtr = Buffer.data() + LHSLen;
780 unsigned RHSLen = PP.getSpelling(Tok: RHS, Buffer&: BufPtr, Invalid: &Invalid);
781 if (Invalid)
782 return true;
783 if (RHSLen && BufPtr != &Buffer[LHSLen])
784 // Really, we want the chars in Buffer!
785 memcpy(dest: &Buffer[LHSLen], src: BufPtr, n: RHSLen);
786
787 // Trim excess space.
788 Buffer.resize(N: LHSLen+RHSLen);
789
790 // Plop the pasted result (including the trailing newline and null) into a
791 // scratch buffer where we can lex it.
792 Token ResultTokTmp;
793 ResultTokTmp.startToken();
794
795 // Claim that the tmp token is a string_literal so that we can get the
796 // character pointer back from CreateString in getLiteralData().
797 ResultTokTmp.setKind(tok::string_literal);
798 PP.CreateString(Str: Buffer, Tok&: ResultTokTmp);
799 SourceLocation ResultTokLoc = ResultTokTmp.getLocation();
800 ResultTokStrPtr = ResultTokTmp.getLiteralData();
801
802 // Lex the resultant pasted token into Result.
803 Token Result;
804
805 if (LHSTok.isAnyIdentifier() && RHS.isAnyIdentifier()) {
806 // Common paste case: identifier+identifier = identifier. Avoid creating
807 // a lexer and other overhead.
808 PP.IncrementPasteCounter(isFast: true);
809 Result.startToken();
810 Result.setKind(tok::raw_identifier);
811 Result.setRawIdentifierData(ResultTokStrPtr);
812 Result.setLocation(ResultTokLoc);
813 Result.setLength(LHSLen+RHSLen);
814 } else {
815 PP.IncrementPasteCounter(isFast: false);
816
817 assert(ResultTokLoc.isFileID() &&
818 "Should be a raw location into scratch buffer");
819 SourceManager &SourceMgr = PP.getSourceManager();
820 FileID LocFileID = SourceMgr.getFileID(SpellingLoc: ResultTokLoc);
821
822 bool Invalid = false;
823 const char *ScratchBufStart
824 = SourceMgr.getBufferData(FID: LocFileID, Invalid: &Invalid).data();
825 if (Invalid)
826 return false;
827
828 // Make a lexer to lex this string from. Lex just this one token.
829 // Make a lexer object so that we lex and expand the paste result.
830 Lexer TL(SourceMgr.getLocForStartOfFile(FID: LocFileID),
831 PP.getLangOpts(), ScratchBufStart,
832 ResultTokStrPtr, ResultTokStrPtr+LHSLen+RHSLen);
833
834 // Lex a token in raw mode. This way it won't look up identifiers
835 // automatically, lexing off the end will return an eof token, and
836 // warnings are disabled. This returns true if the result token is the
837 // entire buffer.
838 bool isInvalid = !TL.LexFromRawLexer(Result);
839
840 // If we got an EOF token, we didn't form even ONE token. For example, we
841 // did "/ ## /" to get "//".
842 isInvalid |= Result.is(K: tok::eof);
843
844 // If pasting the two tokens didn't form a full new token, this is an
845 // error. This occurs with "x ## +" and other stuff. Return with LHSTok
846 // unmodified and with RHS as the next token to lex.
847 if (isInvalid) {
848 // Explicitly convert the token location to have proper expansion
849 // information so that the user knows where it came from.
850 SourceManager &SM = PP.getSourceManager();
851 SourceLocation Loc =
852 SM.createExpansionLoc(SpellingLoc: PasteOpLoc, ExpansionLocStart: ExpandLocStart, ExpansionLocEnd: ExpandLocEnd, Length: 2);
853
854 // Test for the Microsoft extension of /##/ turning into // here on the
855 // error path.
856 if (PP.getLangOpts().MicrosoftExt && LHSTok.is(K: tok::slash) &&
857 RHS.is(K: tok::slash)) {
858 HandleMicrosoftCommentPaste(Tok&: LHSTok, OpLoc: Loc);
859 return true;
860 }
861
862 // Do not emit the error when preprocessing assembler code.
863 if (!PP.getLangOpts().AsmPreprocessor) {
864 // If we're in microsoft extensions mode, downgrade this from a hard
865 // error to an extension that defaults to an error. This allows
866 // disabling it.
867 PP.Diag(Loc, PP.getLangOpts().MicrosoftExt ? diag::ext_pp_bad_paste_ms
868 : diag::err_pp_bad_paste)
869 << Buffer;
870 }
871
872 // An error has occurred so exit loop.
873 break;
874 }
875
876 // Turn ## into 'unknown' to avoid # ## # from looking like a paste
877 // operator.
878 if (Result.is(K: tok::hashhash))
879 Result.setKind(tok::unknown);
880 }
881
882 // Transfer properties of the LHS over the Result.
883 Result.setFlagValue(Flag: Token::StartOfLine , Val: LHSTok.isAtStartOfLine());
884 Result.setFlagValue(Flag: Token::LeadingSpace, Val: LHSTok.hasLeadingSpace());
885
886 // Finally, replace LHS with the result, consume the RHS, and iterate.
887 ++CurIdx;
888 LHSTok = Result;
889 } while (!IsAtEnd() && TokenStream[CurIdx].is(K: tok::hashhash));
890
891 SourceLocation EndLoc = TokenStream[CurIdx - 1].getLocation();
892
893 // The token's current location indicate where the token was lexed from. We
894 // need this information to compute the spelling of the token, but any
895 // diagnostics for the expanded token should appear as if the token was
896 // expanded from the full ## expression. Pull this information together into
897 // a new SourceLocation that captures all of this.
898 SourceManager &SM = PP.getSourceManager();
899 if (StartLoc.isFileID())
900 StartLoc = getExpansionLocForMacroDefLoc(loc: StartLoc);
901 if (EndLoc.isFileID())
902 EndLoc = getExpansionLocForMacroDefLoc(loc: EndLoc);
903 FileID MacroFID = SM.getFileID(SpellingLoc: MacroExpansionStart);
904 while (SM.getFileID(SpellingLoc: StartLoc) != MacroFID)
905 StartLoc = SM.getImmediateExpansionRange(Loc: StartLoc).getBegin();
906 while (SM.getFileID(SpellingLoc: EndLoc) != MacroFID)
907 EndLoc = SM.getImmediateExpansionRange(Loc: EndLoc).getEnd();
908
909 LHSTok.setLocation(SM.createExpansionLoc(SpellingLoc: LHSTok.getLocation(), ExpansionLocStart: StartLoc, ExpansionLocEnd: EndLoc,
910 Length: LHSTok.getLength()));
911
912 // Now that we got the result token, it will be subject to expansion. Since
913 // token pasting re-lexes the result token in raw mode, identifier information
914 // isn't looked up. As such, if the result is an identifier, look up id info.
915 if (LHSTok.is(K: tok::raw_identifier)) {
916 // Look up the identifier info for the token. We disabled identifier lookup
917 // by saying we're skipping contents, so we need to do this manually.
918 PP.LookUpIdentifierInfo(Identifier&: LHSTok);
919 }
920 return false;
921}
922
923/// isNextTokenLParen - If the next token lexed will pop this macro off the
924/// expansion stack, return 2. If the next unexpanded token is a '(', return
925/// 1, otherwise return 0.
926unsigned TokenLexer::isNextTokenLParen() const {
927 // Out of tokens?
928 if (isAtEnd())
929 return 2;
930 return Tokens[CurTokenIdx].is(K: tok::l_paren);
931}
932
933/// isParsingPreprocessorDirective - Return true if we are in the middle of a
934/// preprocessor directive.
935bool TokenLexer::isParsingPreprocessorDirective() const {
936 return Tokens[NumTokens-1].is(K: tok::eod) && !isAtEnd();
937}
938
939/// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes
940/// together to form a comment that comments out everything in the current
941/// macro, other active macros, and anything left on the current physical
942/// source line of the expanded buffer. Handle this by returning the
943/// first token on the next line.
944void TokenLexer::HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc) {
945 PP.Diag(OpLoc, diag::ext_comment_paste_microsoft);
946
947 // We 'comment out' the rest of this macro by just ignoring the rest of the
948 // tokens that have not been lexed yet, if any.
949
950 // Since this must be a macro, mark the macro enabled now that it is no longer
951 // being expanded.
952 assert(Macro && "Token streams can't paste comments");
953 Macro->EnableMacro();
954
955 PP.HandleMicrosoftCommentPaste(Tok);
956}
957
958/// If \arg loc is a file ID and points inside the current macro
959/// definition, returns the appropriate source location pointing at the
960/// macro expansion source location entry, otherwise it returns an invalid
961/// SourceLocation.
962SourceLocation
963TokenLexer::getExpansionLocForMacroDefLoc(SourceLocation loc) const {
964 assert(ExpandLocStart.isValid() && MacroExpansionStart.isValid() &&
965 "Not appropriate for token streams");
966 assert(loc.isValid() && loc.isFileID());
967
968 SourceManager &SM = PP.getSourceManager();
969 assert(SM.isInSLocAddrSpace(loc, MacroDefStart, MacroDefLength) &&
970 "Expected loc to come from the macro definition");
971
972 SourceLocation::UIntTy relativeOffset = 0;
973 SM.isInSLocAddrSpace(Loc: loc, Start: MacroDefStart, Length: MacroDefLength, RelativeOffset: &relativeOffset);
974 return MacroExpansionStart.getLocWithOffset(Offset: relativeOffset);
975}
976
977/// Finds the tokens that are consecutive (from the same FileID)
978/// creates a single SLocEntry, and assigns SourceLocations to each token that
979/// point to that SLocEntry. e.g for
980/// assert(foo == bar);
981/// There will be a single SLocEntry for the "foo == bar" chunk and locations
982/// for the 'foo', '==', 'bar' tokens will point inside that chunk.
983///
984/// \arg begin_tokens will be updated to a position past all the found
985/// consecutive tokens.
986static void updateConsecutiveMacroArgTokens(SourceManager &SM,
987 SourceLocation ExpandLoc,
988 Token *&begin_tokens,
989 Token * end_tokens) {
990 assert(begin_tokens + 1 < end_tokens);
991 SourceLocation BeginLoc = begin_tokens->getLocation();
992 llvm::MutableArrayRef<Token> All(begin_tokens, end_tokens);
993 llvm::MutableArrayRef<Token> Partition;
994
995 auto NearLast = [&, Last = BeginLoc](SourceLocation Loc) mutable {
996 // The maximum distance between two consecutive tokens in a partition.
997 // This is an important trick to avoid using too much SourceLocation address
998 // space!
999 static constexpr SourceLocation::IntTy MaxDistance = 50;
1000 auto Distance = Loc.getRawEncoding() - Last.getRawEncoding();
1001 Last = Loc;
1002 return Distance <= MaxDistance;
1003 };
1004
1005 // Partition the tokens by their FileID.
1006 // This is a hot function, and calling getFileID can be expensive, the
1007 // implementation is optimized by reducing the number of getFileID.
1008 if (BeginLoc.isFileID()) {
1009 // Consecutive tokens not written in macros must be from the same file.
1010 // (Neither #include nor eof can occur inside a macro argument.)
1011 Partition = All.take_while(Pred: [&](const Token &T) {
1012 return T.getLocation().isFileID() && NearLast(T.getLocation());
1013 });
1014 } else {
1015 // Call getFileID once to calculate the bounds, and use the cheaper
1016 // sourcelocation-against-bounds comparison.
1017 FileID BeginFID = SM.getFileID(SpellingLoc: BeginLoc);
1018 SourceLocation Limit =
1019 SM.getComposedLoc(FID: BeginFID, Offset: SM.getFileIDSize(FID: BeginFID));
1020 Partition = All.take_while(Pred: [&](const Token &T) {
1021 // NOTE: the Limit is included! The lexer recovery only ever inserts a
1022 // single token past the end of the FileID, specifically the ) when a
1023 // macro-arg containing a comma should be guarded by parentheses.
1024 //
1025 // It is safe to include the Limit here because SourceManager allocates
1026 // FileSize + 1 for each SLocEntry.
1027 //
1028 // See https://github.com/llvm/llvm-project/issues/60722.
1029 return T.getLocation() >= BeginLoc && T.getLocation() <= Limit
1030 && NearLast(T.getLocation());
1031 });
1032 }
1033 assert(!Partition.empty());
1034
1035 // For the consecutive tokens, find the length of the SLocEntry to contain
1036 // all of them.
1037 SourceLocation::UIntTy FullLength =
1038 Partition.back().getEndLoc().getRawEncoding() -
1039 Partition.front().getLocation().getRawEncoding();
1040 // Create a macro expansion SLocEntry that will "contain" all of the tokens.
1041 SourceLocation Expansion =
1042 SM.createMacroArgExpansionLoc(SpellingLoc: BeginLoc, ExpansionLoc: ExpandLoc, Length: FullLength);
1043
1044#ifdef EXPENSIVE_CHECKS
1045 assert(llvm::all_of(Partition.drop_front(),
1046 [&SM, ID = SM.getFileID(Partition.front().getLocation())](
1047 const Token &T) {
1048 return ID == SM.getFileID(T.getLocation());
1049 }) &&
1050 "Must have the same FIleID!");
1051#endif
1052 // Change the location of the tokens from the spelling location to the new
1053 // expanded location.
1054 for (Token& T : Partition) {
1055 SourceLocation::IntTy RelativeOffset =
1056 T.getLocation().getRawEncoding() - BeginLoc.getRawEncoding();
1057 T.setLocation(Expansion.getLocWithOffset(Offset: RelativeOffset));
1058 }
1059 begin_tokens = &Partition.back() + 1;
1060}
1061
1062/// Creates SLocEntries and updates the locations of macro argument
1063/// tokens to their new expanded locations.
1064///
1065/// \param ArgIdSpellLoc the location of the macro argument id inside the macro
1066/// definition.
1067void TokenLexer::updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc,
1068 Token *begin_tokens,
1069 Token *end_tokens) {
1070 SourceManager &SM = PP.getSourceManager();
1071
1072 SourceLocation ExpandLoc =
1073 getExpansionLocForMacroDefLoc(loc: ArgIdSpellLoc);
1074
1075 while (begin_tokens < end_tokens) {
1076 // If there's only one token just create a SLocEntry for it.
1077 if (end_tokens - begin_tokens == 1) {
1078 Token &Tok = *begin_tokens;
1079 Tok.setLocation(SM.createMacroArgExpansionLoc(SpellingLoc: Tok.getLocation(),
1080 ExpansionLoc: ExpandLoc,
1081 Length: Tok.getLength()));
1082 return;
1083 }
1084
1085 updateConsecutiveMacroArgTokens(SM, ExpandLoc, begin_tokens, end_tokens);
1086 }
1087}
1088
1089void TokenLexer::PropagateLineStartLeadingSpaceInfo(Token &Result) {
1090 AtStartOfLine = Result.isAtStartOfLine();
1091 HasLeadingSpace = Result.hasLeadingSpace();
1092}
1093

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source code of clang/lib/Lex/TokenLexer.cpp