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/SmallString.h"
30#include "llvm/ADT/SmallVector.h"
31#include "llvm/ADT/iterator_range.h"
32#include <cassert>
33#include <cstring>
34#include <optional>
35
36using namespace clang;
37
38/// Create a TokenLexer for the specified macro with the specified actual
39/// arguments. Note that this ctor takes ownership of the ActualArgs pointer.
40void TokenLexer::Init(Token &Tok, SourceLocation ELEnd, MacroInfo *MI,
41 MacroArgs *Actuals) {
42 // If the client is reusing a TokenLexer, make sure to free any memory
43 // associated with it.
44 destroy();
45
46 Macro = MI;
47 ActualArgs = Actuals;
48 CurTokenIdx = 0;
49
50 ExpandLocStart = Tok.getLocation();
51 ExpandLocEnd = ELEnd;
52 AtStartOfLine = Tok.isAtStartOfLine();
53 HasLeadingSpace = Tok.hasLeadingSpace();
54 NextTokGetsSpace = false;
55 Tokens = &*Macro->tokens_begin();
56 OwnsTokens = false;
57 DisableMacroExpansion = false;
58 IsReinject = false;
59 NumTokens = Macro->tokens_end()-Macro->tokens_begin();
60 MacroExpansionStart = SourceLocation();
61
62 SourceManager &SM = PP.getSourceManager();
63 MacroStartSLocOffset = SM.getNextLocalOffset();
64
65 if (NumTokens > 0) {
66 assert(Tokens[0].getLocation().isValid());
67 assert((Tokens[0].getLocation().isFileID() || Tokens[0].is(tok::comment)) &&
68 "Macro defined in macro?");
69 assert(ExpandLocStart.isValid());
70
71 // Reserve a source location entry chunk for the length of the macro
72 // definition. Tokens that get lexed directly from the definition will
73 // have their locations pointing inside this chunk. This is to avoid
74 // creating separate source location entries for each token.
75 MacroDefStart = SM.getExpansionLoc(Loc: Tokens[0].getLocation());
76 MacroDefLength = Macro->getDefinitionLength(SM);
77 MacroExpansionStart = SM.createExpansionLoc(SpellingLoc: MacroDefStart,
78 ExpansionLocStart: ExpandLocStart,
79 ExpansionLocEnd: ExpandLocEnd,
80 Length: MacroDefLength);
81 }
82
83 // If this is a function-like macro, expand the arguments and change
84 // Tokens to point to the expanded tokens.
85 if (Macro->isFunctionLike() && Macro->getNumParams())
86 ExpandFunctionArguments();
87
88 // Mark the macro as currently disabled, so that it is not recursively
89 // expanded. The macro must be disabled only after argument pre-expansion of
90 // function-like macro arguments occurs.
91 Macro->DisableMacro();
92}
93
94/// Create a TokenLexer for the specified token stream. This does not
95/// take ownership of the specified token vector.
96void TokenLexer::Init(const Token *TokArray, unsigned NumToks,
97 bool disableMacroExpansion, bool ownsTokens,
98 bool isReinject) {
99 assert(!isReinject || disableMacroExpansion);
100 // If the client is reusing a TokenLexer, make sure to free any memory
101 // associated with it.
102 destroy();
103
104 Macro = nullptr;
105 ActualArgs = nullptr;
106 Tokens = TokArray;
107 OwnsTokens = ownsTokens;
108 DisableMacroExpansion = disableMacroExpansion;
109 IsReinject = isReinject;
110 NumTokens = NumToks;
111 CurTokenIdx = 0;
112 ExpandLocStart = ExpandLocEnd = SourceLocation();
113 AtStartOfLine = false;
114 HasLeadingSpace = false;
115 NextTokGetsSpace = false;
116 MacroExpansionStart = SourceLocation();
117
118 // Set HasLeadingSpace/AtStartOfLine so that the first token will be
119 // returned unmodified.
120 if (NumToks != 0) {
121 AtStartOfLine = TokArray[0].isAtStartOfLine();
122 HasLeadingSpace = TokArray[0].hasLeadingSpace();
123 }
124}
125
126void TokenLexer::destroy() {
127 // If this was a function-like macro that actually uses its arguments, delete
128 // the expanded tokens.
129 if (OwnsTokens) {
130 delete [] Tokens;
131 Tokens = nullptr;
132 OwnsTokens = false;
133 }
134
135 // TokenLexer owns its formal arguments.
136 if (ActualArgs) ActualArgs->destroy(PP);
137}
138
139bool TokenLexer::MaybeRemoveCommaBeforeVaArgs(
140 SmallVectorImpl<Token> &ResultToks, bool HasPasteOperator, MacroInfo *Macro,
141 unsigned MacroArgNo, Preprocessor &PP) {
142 // Is the macro argument __VA_ARGS__?
143 if (!Macro->isVariadic() || MacroArgNo != Macro->getNumParams()-1)
144 return false;
145
146 // In Microsoft-compatibility mode, a comma is removed in the expansion
147 // of " ... , __VA_ARGS__ " if __VA_ARGS__ is empty. This extension is
148 // not supported by gcc.
149 if (!HasPasteOperator && !PP.getLangOpts().MSVCCompat)
150 return false;
151
152 // GCC removes the comma in the expansion of " ... , ## __VA_ARGS__ " if
153 // __VA_ARGS__ is empty, but not in strict C99 mode where there are no
154 // named arguments, where it remains. In all other modes, including C99
155 // with GNU extensions, it is removed regardless of named arguments.
156 // Microsoft also appears to support this extension, unofficially.
157 if (PP.getLangOpts().C99 && !PP.getLangOpts().GNUMode
158 && Macro->getNumParams() < 2)
159 return false;
160
161 // Is a comma available to be removed?
162 if (ResultToks.empty() || !ResultToks.back().is(K: tok::comma))
163 return false;
164
165 // Issue an extension diagnostic for the paste operator.
166 if (HasPasteOperator)
167 PP.Diag(ResultToks.back().getLocation(), diag::ext_paste_comma);
168
169 // Remove the comma.
170 ResultToks.pop_back();
171
172 if (!ResultToks.empty()) {
173 // If the comma was right after another paste (e.g. "X##,##__VA_ARGS__"),
174 // then removal of the comma should produce a placemarker token (in C99
175 // terms) which we model by popping off the previous ##, giving us a plain
176 // "X" when __VA_ARGS__ is empty.
177 if (ResultToks.back().is(K: tok::hashhash))
178 ResultToks.pop_back();
179
180 // Remember that this comma was elided.
181 ResultToks.back().setFlag(Token::CommaAfterElided);
182 }
183
184 // Never add a space, even if the comma, ##, or arg had a space.
185 NextTokGetsSpace = false;
186 return true;
187}
188
189void TokenLexer::stringifyVAOPTContents(
190 SmallVectorImpl<Token> &ResultToks, const VAOptExpansionContext &VCtx,
191 const SourceLocation VAOPTClosingParenLoc) {
192 const int NumToksPriorToVAOpt = VCtx.getNumberOfTokensPriorToVAOpt();
193 const unsigned int NumVAOptTokens = ResultToks.size() - NumToksPriorToVAOpt;
194 Token *const VAOPTTokens =
195 NumVAOptTokens ? &ResultToks[NumToksPriorToVAOpt] : nullptr;
196
197 SmallVector<Token, 64> ConcatenatedVAOPTResultToks;
198 // FIXME: Should we keep track within VCtx that we did or didnot
199 // encounter pasting - and only then perform this loop.
200
201 // Perform token pasting (concatenation) prior to stringization.
202 for (unsigned int CurTokenIdx = 0; CurTokenIdx != NumVAOptTokens;
203 ++CurTokenIdx) {
204 if (VAOPTTokens[CurTokenIdx].is(K: tok::hashhash)) {
205 assert(CurTokenIdx != 0 &&
206 "Can not have __VAOPT__ contents begin with a ##");
207 Token &LHS = VAOPTTokens[CurTokenIdx - 1];
208 pasteTokens(LHSTok&: LHS, TokenStream: llvm::ArrayRef(VAOPTTokens, NumVAOptTokens),
209 CurIdx&: CurTokenIdx);
210 // Replace the token prior to the first ## in this iteration.
211 ConcatenatedVAOPTResultToks.back() = LHS;
212 if (CurTokenIdx == NumVAOptTokens)
213 break;
214 }
215 ConcatenatedVAOPTResultToks.push_back(Elt: VAOPTTokens[CurTokenIdx]);
216 }
217
218 ConcatenatedVAOPTResultToks.push_back(Elt: VCtx.getEOFTok());
219 // Get the SourceLocation that represents the start location within
220 // the macro definition that marks where this string is substituted
221 // into: i.e. the __VA_OPT__ and the ')' within the spelling of the
222 // macro definition, and use it to indicate that the stringified token
223 // was generated from that location.
224 const SourceLocation ExpansionLocStartWithinMacro =
225 getExpansionLocForMacroDefLoc(loc: VCtx.getVAOptLoc());
226 const SourceLocation ExpansionLocEndWithinMacro =
227 getExpansionLocForMacroDefLoc(loc: VAOPTClosingParenLoc);
228
229 Token StringifiedVAOPT = MacroArgs::StringifyArgument(
230 ArgToks: &ConcatenatedVAOPTResultToks[0], PP, Charify: VCtx.hasCharifyBefore() /*Charify*/,
231 ExpansionLocStart: ExpansionLocStartWithinMacro, ExpansionLocEnd: ExpansionLocEndWithinMacro);
232
233 if (VCtx.getLeadingSpaceForStringifiedToken())
234 StringifiedVAOPT.setFlag(Token::LeadingSpace);
235
236 StringifiedVAOPT.setFlag(Token::StringifiedInMacro);
237 // Resize (shrink) the token stream to just capture this stringified token.
238 ResultToks.resize(N: NumToksPriorToVAOpt + 1);
239 ResultToks.back() = StringifiedVAOPT;
240}
241
242/// Expand the arguments of a function-like macro so that we can quickly
243/// return preexpanded tokens from Tokens.
244void TokenLexer::ExpandFunctionArguments() {
245 SmallVector<Token, 128> ResultToks;
246
247 // Loop through 'Tokens', expanding them into ResultToks. Keep
248 // track of whether we change anything. If not, no need to keep them. If so,
249 // we install the newly expanded sequence as the new 'Tokens' list.
250 bool MadeChange = false;
251
252 std::optional<bool> CalledWithVariadicArguments;
253
254 VAOptExpansionContext VCtx(PP);
255
256 for (unsigned I = 0, E = NumTokens; I != E; ++I) {
257 const Token &CurTok = Tokens[I];
258 // We don't want a space for the next token after a paste
259 // operator. In valid code, the token will get smooshed onto the
260 // preceding one anyway. In assembler-with-cpp mode, invalid
261 // pastes are allowed through: in this case, we do not want the
262 // extra whitespace to be added. For example, we want ". ## foo"
263 // -> ".foo" not ". foo".
264 if (I != 0 && !Tokens[I-1].is(K: tok::hashhash) && CurTok.hasLeadingSpace())
265 NextTokGetsSpace = true;
266
267 if (VCtx.isVAOptToken(T: CurTok)) {
268 MadeChange = true;
269 assert(Tokens[I + 1].is(tok::l_paren) &&
270 "__VA_OPT__ must be followed by '('");
271
272 ++I; // Skip the l_paren
273 VCtx.sawVAOptFollowedByOpeningParens(VAOptLoc: CurTok.getLocation(),
274 NumPriorTokens: ResultToks.size());
275
276 continue;
277 }
278
279 // We have entered into the __VA_OPT__ context, so handle tokens
280 // appropriately.
281 if (VCtx.isInVAOpt()) {
282 // If we are about to process a token that is either an argument to
283 // __VA_OPT__ or its closing rparen, then:
284 // 1) If the token is the closing rparen that exits us out of __VA_OPT__,
285 // perform any necessary stringification or placemarker processing,
286 // and/or skip to the next token.
287 // 2) else if macro was invoked without variadic arguments skip this
288 // token.
289 // 3) else (macro was invoked with variadic arguments) process the token
290 // normally.
291
292 if (Tokens[I].is(K: tok::l_paren))
293 VCtx.sawOpeningParen(LParenLoc: Tokens[I].getLocation());
294 // Continue skipping tokens within __VA_OPT__ if the macro was not
295 // called with variadic arguments, else let the rest of the loop handle
296 // this token. Note sawClosingParen() returns true only if the r_paren matches
297 // the closing r_paren of the __VA_OPT__.
298 if (!Tokens[I].is(K: tok::r_paren) || !VCtx.sawClosingParen()) {
299 // Lazily expand __VA_ARGS__ when we see the first __VA_OPT__.
300 if (!CalledWithVariadicArguments) {
301 CalledWithVariadicArguments =
302 ActualArgs->invokedWithVariadicArgument(MI: Macro, PP);
303 }
304 if (!*CalledWithVariadicArguments) {
305 // Skip this token.
306 continue;
307 }
308 // ... else the macro was called with variadic arguments, and we do not
309 // have a closing rparen - so process this token normally.
310 } else {
311 // Current token is the closing r_paren which marks the end of the
312 // __VA_OPT__ invocation, so handle any place-marker pasting (if
313 // empty) by removing hashhash either before (if exists) or after. And
314 // also stringify the entire contents if VAOPT was preceded by a hash,
315 // but do so only after any token concatenation that needs to occur
316 // within the contents of VAOPT.
317
318 if (VCtx.hasStringifyOrCharifyBefore()) {
319 // Replace all the tokens just added from within VAOPT into a single
320 // stringified token. This requires token-pasting to eagerly occur
321 // within these tokens. If either the contents of VAOPT were empty
322 // or the macro wasn't called with any variadic arguments, the result
323 // is a token that represents an empty string.
324 stringifyVAOPTContents(ResultToks, VCtx,
325 /*ClosingParenLoc*/ VAOPTClosingParenLoc: Tokens[I].getLocation());
326
327 } else if (/*No tokens within VAOPT*/
328 ResultToks.size() == VCtx.getNumberOfTokensPriorToVAOpt()) {
329 // Treat VAOPT as a placemarker token. Eat either the '##' before the
330 // RHS/VAOPT (if one exists, suggesting that the LHS (if any) to that
331 // hashhash was not a placemarker) or the '##'
332 // after VAOPT, but not both.
333
334 if (ResultToks.size() && ResultToks.back().is(K: tok::hashhash)) {
335 ResultToks.pop_back();
336 } else if ((I + 1 != E) && Tokens[I + 1].is(K: tok::hashhash)) {
337 ++I; // Skip the following hashhash.
338 }
339 } else {
340 // If there's a ## before the __VA_OPT__, we might have discovered
341 // that the __VA_OPT__ begins with a placeholder. We delay action on
342 // that to now to avoid messing up our stashed count of tokens before
343 // __VA_OPT__.
344 if (VCtx.beginsWithPlaceholder()) {
345 assert(VCtx.getNumberOfTokensPriorToVAOpt() > 0 &&
346 ResultToks.size() >= VCtx.getNumberOfTokensPriorToVAOpt() &&
347 ResultToks[VCtx.getNumberOfTokensPriorToVAOpt() - 1].is(
348 tok::hashhash) &&
349 "no token paste before __VA_OPT__");
350 ResultToks.erase(CI: ResultToks.begin() +
351 VCtx.getNumberOfTokensPriorToVAOpt() - 1);
352 }
353 // If the expansion of __VA_OPT__ ends with a placeholder, eat any
354 // following '##' token.
355 if (VCtx.endsWithPlaceholder() && I + 1 != E &&
356 Tokens[I + 1].is(K: tok::hashhash)) {
357 ++I;
358 }
359 }
360 VCtx.reset();
361 // We processed __VA_OPT__'s closing paren (and the exit out of
362 // __VA_OPT__), so skip to the next token.
363 continue;
364 }
365 }
366
367 // If we found the stringify operator, get the argument stringified. The
368 // preprocessor already verified that the following token is a macro
369 // parameter or __VA_OPT__ when the #define was lexed.
370
371 if (CurTok.isOneOf(K1: tok::hash, K2: tok::hashat)) {
372 int ArgNo = Macro->getParameterNum(Arg: Tokens[I+1].getIdentifierInfo());
373 assert((ArgNo != -1 || VCtx.isVAOptToken(Tokens[I + 1])) &&
374 "Token following # is not an argument or __VA_OPT__!");
375
376 if (ArgNo == -1) {
377 // Handle the __VA_OPT__ case.
378 VCtx.sawHashOrHashAtBefore(HasLeadingSpace: NextTokGetsSpace,
379 IsHashAt: CurTok.is(K: tok::hashat));
380 continue;
381 }
382 // Else handle the simple argument case.
383 SourceLocation ExpansionLocStart =
384 getExpansionLocForMacroDefLoc(loc: CurTok.getLocation());
385 SourceLocation ExpansionLocEnd =
386 getExpansionLocForMacroDefLoc(loc: Tokens[I+1].getLocation());
387
388 bool Charify = CurTok.is(K: tok::hashat);
389 const Token *UnexpArg = ActualArgs->getUnexpArgument(Arg: ArgNo);
390 Token Res = MacroArgs::StringifyArgument(
391 ArgToks: UnexpArg, PP, Charify, ExpansionLocStart, ExpansionLocEnd);
392 Res.setFlag(Token::StringifiedInMacro);
393
394 // The stringified/charified string leading space flag gets set to match
395 // the #/#@ operator.
396 if (NextTokGetsSpace)
397 Res.setFlag(Token::LeadingSpace);
398
399 ResultToks.push_back(Elt: Res);
400 MadeChange = true;
401 ++I; // Skip arg name.
402 NextTokGetsSpace = false;
403 continue;
404 }
405
406 // Find out if there is a paste (##) operator before or after the token.
407 bool NonEmptyPasteBefore =
408 !ResultToks.empty() && ResultToks.back().is(K: tok::hashhash);
409 bool PasteBefore = I != 0 && Tokens[I-1].is(K: tok::hashhash);
410 bool PasteAfter = I+1 != E && Tokens[I+1].is(K: tok::hashhash);
411 bool RParenAfter = I+1 != E && Tokens[I+1].is(K: tok::r_paren);
412
413 assert((!NonEmptyPasteBefore || PasteBefore || VCtx.isInVAOpt()) &&
414 "unexpected ## in ResultToks");
415
416 // Otherwise, if this is not an argument token, just add the token to the
417 // output buffer.
418 IdentifierInfo *II = CurTok.getIdentifierInfo();
419 int ArgNo = II ? Macro->getParameterNum(Arg: II) : -1;
420 if (ArgNo == -1) {
421 // This isn't an argument, just add it.
422 ResultToks.push_back(Elt: CurTok);
423
424 if (NextTokGetsSpace) {
425 ResultToks.back().setFlag(Token::LeadingSpace);
426 NextTokGetsSpace = false;
427 } else if (PasteBefore && !NonEmptyPasteBefore)
428 ResultToks.back().clearFlag(Flag: Token::LeadingSpace);
429
430 continue;
431 }
432
433 // An argument is expanded somehow, the result is different than the
434 // input.
435 MadeChange = true;
436
437 // Otherwise, this is a use of the argument.
438
439 // In Microsoft mode, remove the comma before __VA_ARGS__ to ensure there
440 // are no trailing commas if __VA_ARGS__ is empty.
441 if (!PasteBefore && ActualArgs->isVarargsElidedUse() &&
442 MaybeRemoveCommaBeforeVaArgs(ResultToks,
443 /*HasPasteOperator=*/false,
444 Macro, MacroArgNo: ArgNo, PP))
445 continue;
446
447 // If it is not the LHS/RHS of a ## operator, we must pre-expand the
448 // argument and substitute the expanded tokens into the result. This is
449 // C99 6.10.3.1p1.
450 if (!PasteBefore && !PasteAfter) {
451 const Token *ResultArgToks;
452
453 // Only preexpand the argument if it could possibly need it. This
454 // avoids some work in common cases.
455 const Token *ArgTok = ActualArgs->getUnexpArgument(Arg: ArgNo);
456 if (ActualArgs->ArgNeedsPreexpansion(ArgTok, PP))
457 ResultArgToks = &ActualArgs->getPreExpArgument(Arg: ArgNo, PP)[0];
458 else
459 ResultArgToks = ArgTok; // Use non-preexpanded tokens.
460
461 // If the arg token expanded into anything, append it.
462 if (ResultArgToks->isNot(K: tok::eof)) {
463 size_t FirstResult = ResultToks.size();
464 unsigned NumToks = MacroArgs::getArgLength(ArgPtr: ResultArgToks);
465 ResultToks.append(in_start: ResultArgToks, in_end: ResultArgToks+NumToks);
466
467 // In Microsoft-compatibility mode, we follow MSVC's preprocessing
468 // behavior by not considering single commas from nested macro
469 // expansions as argument separators. Set a flag on the token so we can
470 // test for this later when the macro expansion is processed.
471 if (PP.getLangOpts().MSVCCompat && NumToks == 1 &&
472 ResultToks.back().is(K: tok::comma))
473 ResultToks.back().setFlag(Token::IgnoredComma);
474
475 // If the '##' came from expanding an argument, turn it into 'unknown'
476 // to avoid pasting.
477 for (Token &Tok : llvm::drop_begin(RangeOrContainer&: ResultToks, N: FirstResult))
478 if (Tok.is(K: tok::hashhash))
479 Tok.setKind(tok::unknown);
480
481 if(ExpandLocStart.isValid()) {
482 updateLocForMacroArgTokens(ArgIdSpellLoc: CurTok.getLocation(),
483 begin_tokens: ResultToks.begin()+FirstResult,
484 end_tokens: ResultToks.end());
485 }
486
487 // If any tokens were substituted from the argument, the whitespace
488 // before the first token should match the whitespace of the arg
489 // identifier.
490 ResultToks[FirstResult].setFlagValue(Flag: Token::LeadingSpace,
491 Val: NextTokGetsSpace);
492 ResultToks[FirstResult].setFlagValue(Flag: Token::StartOfLine, Val: false);
493 NextTokGetsSpace = false;
494 } else {
495 // We're creating a placeholder token. Usually this doesn't matter,
496 // but it can affect paste behavior when at the start or end of a
497 // __VA_OPT__.
498 if (NonEmptyPasteBefore) {
499 // We're imagining a placeholder token is inserted here. If this is
500 // the first token in a __VA_OPT__ after a ##, delete the ##.
501 assert(VCtx.isInVAOpt() && "should only happen inside a __VA_OPT__");
502 VCtx.hasPlaceholderAfterHashhashAtStart();
503 } else if (RParenAfter)
504 VCtx.hasPlaceholderBeforeRParen();
505 }
506 continue;
507 }
508
509 // Okay, we have a token that is either the LHS or RHS of a paste (##)
510 // argument. It gets substituted as its non-pre-expanded tokens.
511 const Token *ArgToks = ActualArgs->getUnexpArgument(Arg: ArgNo);
512 unsigned NumToks = MacroArgs::getArgLength(ArgPtr: ArgToks);
513 if (NumToks) { // Not an empty argument?
514 bool VaArgsPseudoPaste = false;
515 // If this is the GNU ", ## __VA_ARGS__" extension, and we just learned
516 // that __VA_ARGS__ expands to multiple tokens, avoid a pasting error when
517 // the expander tries to paste ',' with the first token of the __VA_ARGS__
518 // expansion.
519 if (NonEmptyPasteBefore && ResultToks.size() >= 2 &&
520 ResultToks[ResultToks.size()-2].is(K: tok::comma) &&
521 (unsigned)ArgNo == Macro->getNumParams()-1 &&
522 Macro->isVariadic()) {
523 VaArgsPseudoPaste = true;
524 // Remove the paste operator, report use of the extension.
525 PP.Diag(ResultToks.pop_back_val().getLocation(), diag::ext_paste_comma);
526 }
527
528 ResultToks.append(in_start: ArgToks, in_end: ArgToks+NumToks);
529
530 // If the '##' came from expanding an argument, turn it into 'unknown'
531 // to avoid pasting.
532 for (Token &Tok : llvm::make_range(x: ResultToks.end() - NumToks,
533 y: ResultToks.end())) {
534 if (Tok.is(K: tok::hashhash))
535 Tok.setKind(tok::unknown);
536 }
537
538 if (ExpandLocStart.isValid()) {
539 updateLocForMacroArgTokens(ArgIdSpellLoc: CurTok.getLocation(),
540 begin_tokens: ResultToks.end()-NumToks, end_tokens: ResultToks.end());
541 }
542
543 // Transfer the leading whitespace information from the token
544 // (the macro argument) onto the first token of the
545 // expansion. Note that we don't do this for the GNU
546 // pseudo-paste extension ", ## __VA_ARGS__".
547 if (!VaArgsPseudoPaste) {
548 ResultToks[ResultToks.size() - NumToks].setFlagValue(Flag: Token::StartOfLine,
549 Val: false);
550 ResultToks[ResultToks.size() - NumToks].setFlagValue(
551 Flag: Token::LeadingSpace, Val: NextTokGetsSpace);
552 }
553
554 NextTokGetsSpace = false;
555 continue;
556 }
557
558 // If an empty argument is on the LHS or RHS of a paste, the standard (C99
559 // 6.10.3.3p2,3) calls for a bunch of placemarker stuff to occur. We
560 // implement this by eating ## operators when a LHS or RHS expands to
561 // empty.
562 if (PasteAfter) {
563 // Discard the argument token and skip (don't copy to the expansion
564 // buffer) the paste operator after it.
565 ++I;
566 continue;
567 }
568
569 if (RParenAfter && !NonEmptyPasteBefore)
570 VCtx.hasPlaceholderBeforeRParen();
571
572 // If this is on the RHS of a paste operator, we've already copied the
573 // paste operator to the ResultToks list, unless the LHS was empty too.
574 // Remove it.
575 assert(PasteBefore);
576 if (NonEmptyPasteBefore) {
577 assert(ResultToks.back().is(tok::hashhash));
578 // Do not remove the paste operator if it is the one before __VA_OPT__
579 // (and we are still processing tokens within VA_OPT). We handle the case
580 // of removing the paste operator if __VA_OPT__ reduces to the notional
581 // placemarker above when we encounter the closing paren of VA_OPT.
582 if (!VCtx.isInVAOpt() ||
583 ResultToks.size() > VCtx.getNumberOfTokensPriorToVAOpt())
584 ResultToks.pop_back();
585 else
586 VCtx.hasPlaceholderAfterHashhashAtStart();
587 }
588
589 // If this is the __VA_ARGS__ token, and if the argument wasn't provided,
590 // and if the macro had at least one real argument, and if the token before
591 // the ## was a comma, remove the comma. This is a GCC extension which is
592 // disabled when using -std=c99.
593 if (ActualArgs->isVarargsElidedUse())
594 MaybeRemoveCommaBeforeVaArgs(ResultToks,
595 /*HasPasteOperator=*/true,
596 Macro, MacroArgNo: ArgNo, PP);
597 }
598
599 // If anything changed, install this as the new Tokens list.
600 if (MadeChange) {
601 assert(!OwnsTokens && "This would leak if we already own the token list");
602 // This is deleted in the dtor.
603 NumTokens = ResultToks.size();
604 // The tokens will be added to Preprocessor's cache and will be removed
605 // when this TokenLexer finishes lexing them.
606 Tokens = PP.cacheMacroExpandedTokens(tokLexer: this, tokens: ResultToks);
607
608 // The preprocessor cache of macro expanded tokens owns these tokens,not us.
609 OwnsTokens = false;
610 }
611}
612
613/// Checks if two tokens form wide string literal.
614static bool isWideStringLiteralFromMacro(const Token &FirstTok,
615 const Token &SecondTok) {
616 return FirstTok.is(K: tok::identifier) &&
617 FirstTok.getIdentifierInfo()->isStr(Str: "L") && SecondTok.isLiteral() &&
618 SecondTok.stringifiedInMacro();
619}
620
621/// Lex - Lex and return a token from this macro stream.
622bool TokenLexer::Lex(Token &Tok) {
623 // Lexing off the end of the macro, pop this macro off the expansion stack.
624 if (isAtEnd()) {
625 // If this is a macro (not a token stream), mark the macro enabled now
626 // that it is no longer being expanded.
627 if (Macro) Macro->EnableMacro();
628
629 Tok.startToken();
630 Tok.setFlagValue(Flag: Token::StartOfLine , Val: AtStartOfLine);
631 Tok.setFlagValue(Flag: Token::LeadingSpace, Val: HasLeadingSpace || NextTokGetsSpace);
632 if (CurTokenIdx == 0)
633 Tok.setFlag(Token::LeadingEmptyMacro);
634 return PP.HandleEndOfTokenLexer(Result&: Tok);
635 }
636
637 SourceManager &SM = PP.getSourceManager();
638
639 // If this is the first token of the expanded result, we inherit spacing
640 // properties later.
641 bool isFirstToken = CurTokenIdx == 0;
642
643 // Get the next token to return.
644 Tok = Tokens[CurTokenIdx++];
645 if (IsReinject)
646 Tok.setFlag(Token::IsReinjected);
647
648 bool TokenIsFromPaste = false;
649
650 // If this token is followed by a token paste (##) operator, paste the tokens!
651 // Note that ## is a normal token when not expanding a macro.
652 if (!isAtEnd() && Macro &&
653 (Tokens[CurTokenIdx].is(K: tok::hashhash) ||
654 // Special processing of L#x macros in -fms-compatibility mode.
655 // Microsoft compiler is able to form a wide string literal from
656 // 'L#macro_arg' construct in a function-like macro.
657 (PP.getLangOpts().MSVCCompat &&
658 isWideStringLiteralFromMacro(FirstTok: Tok, SecondTok: Tokens[CurTokenIdx])))) {
659 // When handling the microsoft /##/ extension, the final token is
660 // returned by pasteTokens, not the pasted token.
661 if (pasteTokens(Tok))
662 return true;
663
664 TokenIsFromPaste = true;
665 }
666
667 // The token's current location indicate where the token was lexed from. We
668 // need this information to compute the spelling of the token, but any
669 // diagnostics for the expanded token should appear as if they came from
670 // ExpansionLoc. Pull this information together into a new SourceLocation
671 // that captures all of this.
672 if (ExpandLocStart.isValid() && // Don't do this for token streams.
673 // Check that the token's location was not already set properly.
674 SM.isBeforeInSLocAddrSpace(LHS: Tok.getLocation(), RHS: MacroStartSLocOffset)) {
675 SourceLocation instLoc;
676 if (Tok.is(K: tok::comment)) {
677 instLoc = SM.createExpansionLoc(SpellingLoc: Tok.getLocation(),
678 ExpansionLocStart: ExpandLocStart,
679 ExpansionLocEnd: ExpandLocEnd,
680 Length: Tok.getLength());
681 } else {
682 instLoc = getExpansionLocForMacroDefLoc(loc: Tok.getLocation());
683 }
684
685 Tok.setLocation(instLoc);
686 }
687
688 // If this is the first token, set the lexical properties of the token to
689 // match the lexical properties of the macro identifier.
690 if (isFirstToken) {
691 Tok.setFlagValue(Flag: Token::StartOfLine , Val: AtStartOfLine);
692 Tok.setFlagValue(Flag: Token::LeadingSpace, Val: HasLeadingSpace);
693 } else {
694 // If this is not the first token, we may still need to pass through
695 // leading whitespace if we've expanded a macro.
696 if (AtStartOfLine) Tok.setFlag(Token::StartOfLine);
697 if (HasLeadingSpace) Tok.setFlag(Token::LeadingSpace);
698 }
699 AtStartOfLine = false;
700 HasLeadingSpace = false;
701
702 // Handle recursive expansion!
703 if (!Tok.isAnnotation() && Tok.getIdentifierInfo() != nullptr) {
704 // Change the kind of this identifier to the appropriate token kind, e.g.
705 // turning "for" into a keyword.
706 IdentifierInfo *II = Tok.getIdentifierInfo();
707 Tok.setKind(II->getTokenID());
708
709 // If this identifier was poisoned and from a paste, emit an error. This
710 // won't be handled by Preprocessor::HandleIdentifier because this is coming
711 // from a macro expansion.
712 if (II->isPoisoned() && TokenIsFromPaste) {
713 PP.HandlePoisonedIdentifier(Identifier&: Tok);
714 }
715
716 if (!DisableMacroExpansion && II->isHandleIdentifierCase())
717 return PP.HandleIdentifier(Identifier&: Tok);
718 }
719
720 // Otherwise, return a normal token.
721 return true;
722}
723
724bool TokenLexer::pasteTokens(Token &Tok) {
725 return pasteTokens(LHSTok&: Tok, TokenStream: llvm::ArrayRef(Tokens, NumTokens), CurIdx&: CurTokenIdx);
726}
727
728/// LHSTok is the LHS of a ## operator, and CurTokenIdx is the ##
729/// operator. Read the ## and RHS, and paste the LHS/RHS together. If there
730/// are more ## after it, chomp them iteratively. Return the result as LHSTok.
731/// If this returns true, the caller should immediately return the token.
732bool TokenLexer::pasteTokens(Token &LHSTok, ArrayRef<Token> TokenStream,
733 unsigned int &CurIdx) {
734 assert(CurIdx > 0 && "## can not be the first token within tokens");
735 assert((TokenStream[CurIdx].is(tok::hashhash) ||
736 (PP.getLangOpts().MSVCCompat &&
737 isWideStringLiteralFromMacro(LHSTok, TokenStream[CurIdx]))) &&
738 "Token at this Index must be ## or part of the MSVC 'L "
739 "#macro-arg' pasting pair");
740
741 // MSVC: If previous token was pasted, this must be a recovery from an invalid
742 // paste operation. Ignore spaces before this token to mimic MSVC output.
743 // Required for generating valid UUID strings in some MS headers.
744 if (PP.getLangOpts().MicrosoftExt && (CurIdx >= 2) &&
745 TokenStream[CurIdx - 2].is(K: tok::hashhash))
746 LHSTok.clearFlag(Flag: Token::LeadingSpace);
747
748 SmallString<128> Buffer;
749 const char *ResultTokStrPtr = nullptr;
750 SourceLocation StartLoc = LHSTok.getLocation();
751 SourceLocation PasteOpLoc;
752
753 auto IsAtEnd = [&TokenStream, &CurIdx] {
754 return TokenStream.size() == CurIdx;
755 };
756
757 do {
758 // Consume the ## operator if any.
759 PasteOpLoc = TokenStream[CurIdx].getLocation();
760 if (TokenStream[CurIdx].is(K: tok::hashhash))
761 ++CurIdx;
762 assert(!IsAtEnd() && "No token on the RHS of a paste operator!");
763
764 // Get the RHS token.
765 const Token &RHS = TokenStream[CurIdx];
766
767 // Allocate space for the result token. This is guaranteed to be enough for
768 // the two tokens.
769 Buffer.resize(N: LHSTok.getLength() + RHS.getLength());
770
771 // Get the spelling of the LHS token in Buffer.
772 const char *BufPtr = &Buffer[0];
773 bool Invalid = false;
774 unsigned LHSLen = PP.getSpelling(Tok: LHSTok, Buffer&: BufPtr, Invalid: &Invalid);
775 if (BufPtr != &Buffer[0]) // Really, we want the chars in Buffer!
776 memcpy(dest: &Buffer[0], src: BufPtr, n: LHSLen);
777 if (Invalid)
778 return true;
779
780 BufPtr = Buffer.data() + LHSLen;
781 unsigned RHSLen = PP.getSpelling(Tok: RHS, Buffer&: BufPtr, Invalid: &Invalid);
782 if (Invalid)
783 return true;
784 if (RHSLen && BufPtr != &Buffer[LHSLen])
785 // Really, we want the chars in Buffer!
786 memcpy(dest: &Buffer[LHSLen], src: BufPtr, n: RHSLen);
787
788 // Trim excess space.
789 Buffer.resize(N: LHSLen+RHSLen);
790
791 // Plop the pasted result (including the trailing newline and null) into a
792 // scratch buffer where we can lex it.
793 Token ResultTokTmp;
794 ResultTokTmp.startToken();
795
796 // Claim that the tmp token is a string_literal so that we can get the
797 // character pointer back from CreateString in getLiteralData().
798 ResultTokTmp.setKind(tok::string_literal);
799 PP.CreateString(Str: Buffer, Tok&: ResultTokTmp);
800 SourceLocation ResultTokLoc = ResultTokTmp.getLocation();
801 ResultTokStrPtr = ResultTokTmp.getLiteralData();
802
803 // Lex the resultant pasted token into Result.
804 Token Result;
805
806 if (LHSTok.isAnyIdentifier() && RHS.isAnyIdentifier()) {
807 // Common paste case: identifier+identifier = identifier. Avoid creating
808 // a lexer and other overhead.
809 PP.IncrementPasteCounter(isFast: true);
810 Result.startToken();
811 Result.setKind(tok::raw_identifier);
812 Result.setRawIdentifierData(ResultTokStrPtr);
813 Result.setLocation(ResultTokLoc);
814 Result.setLength(LHSLen+RHSLen);
815 } else {
816 PP.IncrementPasteCounter(isFast: false);
817
818 assert(ResultTokLoc.isFileID() &&
819 "Should be a raw location into scratch buffer");
820 SourceManager &SourceMgr = PP.getSourceManager();
821 FileID LocFileID = SourceMgr.getFileID(SpellingLoc: ResultTokLoc);
822
823 bool Invalid = false;
824 const char *ScratchBufStart
825 = SourceMgr.getBufferData(FID: LocFileID, Invalid: &Invalid).data();
826 if (Invalid)
827 return false;
828
829 // Make a lexer to lex this string from. Lex just this one token.
830 // Make a lexer object so that we lex and expand the paste result.
831 Lexer TL(SourceMgr.getLocForStartOfFile(FID: LocFileID),
832 PP.getLangOpts(), ScratchBufStart,
833 ResultTokStrPtr, ResultTokStrPtr+LHSLen+RHSLen);
834
835 // Lex a token in raw mode. This way it won't look up identifiers
836 // automatically, lexing off the end will return an eof token, and
837 // warnings are disabled. This returns true if the result token is the
838 // entire buffer.
839 bool isInvalid = !TL.LexFromRawLexer(Result);
840
841 // If we got an EOF token, we didn't form even ONE token. For example, we
842 // did "/ ## /" to get "//".
843 isInvalid |= Result.is(K: tok::eof);
844
845 // If pasting the two tokens didn't form a full new token, this is an
846 // error. This occurs with "x ## +" and other stuff. Return with LHSTok
847 // unmodified and with RHS as the next token to lex.
848 if (isInvalid) {
849 // Explicitly convert the token location to have proper expansion
850 // information so that the user knows where it came from.
851 SourceManager &SM = PP.getSourceManager();
852 SourceLocation Loc =
853 SM.createExpansionLoc(SpellingLoc: PasteOpLoc, ExpansionLocStart: ExpandLocStart, ExpansionLocEnd: ExpandLocEnd, Length: 2);
854
855 // Test for the Microsoft extension of /##/ turning into // here on the
856 // error path.
857 if (PP.getLangOpts().MicrosoftExt && LHSTok.is(K: tok::slash) &&
858 RHS.is(K: tok::slash)) {
859 HandleMicrosoftCommentPaste(Tok&: LHSTok, OpLoc: Loc);
860 return true;
861 }
862
863 // Do not emit the error when preprocessing assembler code.
864 if (!PP.getLangOpts().AsmPreprocessor) {
865 // If we're in microsoft extensions mode, downgrade this from a hard
866 // error to an extension that defaults to an error. This allows
867 // disabling it.
868 PP.Diag(Loc, PP.getLangOpts().MicrosoftExt ? diag::ext_pp_bad_paste_ms
869 : diag::err_pp_bad_paste)
870 << Buffer;
871 }
872
873 // An error has occurred so exit loop.
874 break;
875 }
876
877 // Turn ## into 'unknown' to avoid # ## # from looking like a paste
878 // operator.
879 if (Result.is(K: tok::hashhash))
880 Result.setKind(tok::unknown);
881 }
882
883 // Transfer properties of the LHS over the Result.
884 Result.setFlagValue(Flag: Token::StartOfLine , Val: LHSTok.isAtStartOfLine());
885 Result.setFlagValue(Flag: Token::LeadingSpace, Val: LHSTok.hasLeadingSpace());
886
887 // Finally, replace LHS with the result, consume the RHS, and iterate.
888 ++CurIdx;
889 LHSTok = Result;
890 } while (!IsAtEnd() && TokenStream[CurIdx].is(K: tok::hashhash));
891
892 SourceLocation EndLoc = TokenStream[CurIdx - 1].getLocation();
893
894 // The token's current location indicate where the token was lexed from. We
895 // need this information to compute the spelling of the token, but any
896 // diagnostics for the expanded token should appear as if the token was
897 // expanded from the full ## expression. Pull this information together into
898 // a new SourceLocation that captures all of this.
899 SourceManager &SM = PP.getSourceManager();
900 if (StartLoc.isFileID())
901 StartLoc = getExpansionLocForMacroDefLoc(loc: StartLoc);
902 if (EndLoc.isFileID())
903 EndLoc = getExpansionLocForMacroDefLoc(loc: EndLoc);
904 FileID MacroFID = SM.getFileID(SpellingLoc: MacroExpansionStart);
905 while (SM.getFileID(SpellingLoc: StartLoc) != MacroFID)
906 StartLoc = SM.getImmediateExpansionRange(Loc: StartLoc).getBegin();
907 while (SM.getFileID(SpellingLoc: EndLoc) != MacroFID)
908 EndLoc = SM.getImmediateExpansionRange(Loc: EndLoc).getEnd();
909
910 LHSTok.setLocation(SM.createExpansionLoc(SpellingLoc: LHSTok.getLocation(), ExpansionLocStart: StartLoc, ExpansionLocEnd: EndLoc,
911 Length: LHSTok.getLength()));
912
913 // Now that we got the result token, it will be subject to expansion. Since
914 // token pasting re-lexes the result token in raw mode, identifier information
915 // isn't looked up. As such, if the result is an identifier, look up id info.
916 if (LHSTok.is(K: tok::raw_identifier)) {
917 // Look up the identifier info for the token. We disabled identifier lookup
918 // by saying we're skipping contents, so we need to do this manually.
919 PP.LookUpIdentifierInfo(Identifier&: LHSTok);
920 }
921 return false;
922}
923
924/// isNextTokenLParen - If the next token lexed will pop this macro off the
925/// expansion stack, return 2. If the next unexpanded token is a '(', return
926/// 1, otherwise return 0.
927unsigned TokenLexer::isNextTokenLParen() const {
928 // Out of tokens?
929 if (isAtEnd())
930 return 2;
931 return Tokens[CurTokenIdx].is(K: tok::l_paren);
932}
933
934/// isParsingPreprocessorDirective - Return true if we are in the middle of a
935/// preprocessor directive.
936bool TokenLexer::isParsingPreprocessorDirective() const {
937 return Tokens[NumTokens-1].is(K: tok::eod) && !isAtEnd();
938}
939
940/// HandleMicrosoftCommentPaste - In microsoft compatibility mode, /##/ pastes
941/// together to form a comment that comments out everything in the current
942/// macro, other active macros, and anything left on the current physical
943/// source line of the expanded buffer. Handle this by returning the
944/// first token on the next line.
945void TokenLexer::HandleMicrosoftCommentPaste(Token &Tok, SourceLocation OpLoc) {
946 PP.Diag(OpLoc, diag::ext_comment_paste_microsoft);
947
948 // We 'comment out' the rest of this macro by just ignoring the rest of the
949 // tokens that have not been lexed yet, if any.
950
951 // Since this must be a macro, mark the macro enabled now that it is no longer
952 // being expanded.
953 assert(Macro && "Token streams can't paste comments");
954 Macro->EnableMacro();
955
956 PP.HandleMicrosoftCommentPaste(Tok);
957}
958
959/// If \arg loc is a file ID and points inside the current macro
960/// definition, returns the appropriate source location pointing at the
961/// macro expansion source location entry, otherwise it returns an invalid
962/// SourceLocation.
963SourceLocation
964TokenLexer::getExpansionLocForMacroDefLoc(SourceLocation loc) const {
965 assert(ExpandLocStart.isValid() && MacroExpansionStart.isValid() &&
966 "Not appropriate for token streams");
967 assert(loc.isValid() && loc.isFileID());
968
969 SourceManager &SM = PP.getSourceManager();
970 assert(SM.isInSLocAddrSpace(loc, MacroDefStart, MacroDefLength) &&
971 "Expected loc to come from the macro definition");
972
973 SourceLocation::UIntTy relativeOffset = 0;
974 SM.isInSLocAddrSpace(Loc: loc, Start: MacroDefStart, Length: MacroDefLength, RelativeOffset: &relativeOffset);
975 return MacroExpansionStart.getLocWithOffset(Offset: relativeOffset);
976}
977
978/// Finds the tokens that are consecutive (from the same FileID)
979/// creates a single SLocEntry, and assigns SourceLocations to each token that
980/// point to that SLocEntry. e.g for
981/// assert(foo == bar);
982/// There will be a single SLocEntry for the "foo == bar" chunk and locations
983/// for the 'foo', '==', 'bar' tokens will point inside that chunk.
984///
985/// \arg begin_tokens will be updated to a position past all the found
986/// consecutive tokens.
987static void updateConsecutiveMacroArgTokens(SourceManager &SM,
988 SourceLocation ExpandLoc,
989 Token *&begin_tokens,
990 Token * end_tokens) {
991 assert(begin_tokens + 1 < end_tokens);
992 SourceLocation BeginLoc = begin_tokens->getLocation();
993 llvm::MutableArrayRef<Token> All(begin_tokens, end_tokens);
994 llvm::MutableArrayRef<Token> Partition;
995
996 auto NearLast = [&, Last = BeginLoc](SourceLocation Loc) mutable {
997 // The maximum distance between two consecutive tokens in a partition.
998 // This is an important trick to avoid using too much SourceLocation address
999 // space!
1000 static constexpr SourceLocation::IntTy MaxDistance = 50;
1001 auto Distance = Loc.getRawEncoding() - Last.getRawEncoding();
1002 Last = Loc;
1003 return Distance <= MaxDistance;
1004 };
1005
1006 // Partition the tokens by their FileID.
1007 // This is a hot function, and calling getFileID can be expensive, the
1008 // implementation is optimized by reducing the number of getFileID.
1009 if (BeginLoc.isFileID()) {
1010 // Consecutive tokens not written in macros must be from the same file.
1011 // (Neither #include nor eof can occur inside a macro argument.)
1012 Partition = All.take_while(Pred: [&](const Token &T) {
1013 return T.getLocation().isFileID() && NearLast(T.getLocation());
1014 });
1015 } else {
1016 // Call getFileID once to calculate the bounds, and use the cheaper
1017 // sourcelocation-against-bounds comparison.
1018 FileID BeginFID = SM.getFileID(SpellingLoc: BeginLoc);
1019 SourceLocation Limit =
1020 SM.getComposedLoc(FID: BeginFID, Offset: SM.getFileIDSize(FID: BeginFID));
1021 Partition = All.take_while(Pred: [&](const Token &T) {
1022 // NOTE: the Limit is included! The lexer recovery only ever inserts a
1023 // single token past the end of the FileID, specifically the ) when a
1024 // macro-arg containing a comma should be guarded by parentheses.
1025 //
1026 // It is safe to include the Limit here because SourceManager allocates
1027 // FileSize + 1 for each SLocEntry.
1028 //
1029 // See https://github.com/llvm/llvm-project/issues/60722.
1030 return T.getLocation() >= BeginLoc && T.getLocation() <= Limit
1031 && NearLast(T.getLocation());
1032 });
1033 }
1034 assert(!Partition.empty());
1035
1036 // For the consecutive tokens, find the length of the SLocEntry to contain
1037 // all of them.
1038 SourceLocation::UIntTy FullLength =
1039 Partition.back().getEndLoc().getRawEncoding() -
1040 Partition.front().getLocation().getRawEncoding();
1041 // Create a macro expansion SLocEntry that will "contain" all of the tokens.
1042 SourceLocation Expansion =
1043 SM.createMacroArgExpansionLoc(SpellingLoc: BeginLoc, ExpansionLoc: ExpandLoc, Length: FullLength);
1044
1045#ifdef EXPENSIVE_CHECKS
1046 assert(llvm::all_of(Partition.drop_front(),
1047 [&SM, ID = SM.getFileID(Partition.front().getLocation())](
1048 const Token &T) {
1049 return ID == SM.getFileID(T.getLocation());
1050 }) &&
1051 "Must have the same FIleID!");
1052#endif
1053 // Change the location of the tokens from the spelling location to the new
1054 // expanded location.
1055 for (Token& T : Partition) {
1056 SourceLocation::IntTy RelativeOffset =
1057 T.getLocation().getRawEncoding() - BeginLoc.getRawEncoding();
1058 T.setLocation(Expansion.getLocWithOffset(Offset: RelativeOffset));
1059 }
1060 begin_tokens = &Partition.back() + 1;
1061}
1062
1063/// Creates SLocEntries and updates the locations of macro argument
1064/// tokens to their new expanded locations.
1065///
1066/// \param ArgIdSpellLoc the location of the macro argument id inside the macro
1067/// definition.
1068void TokenLexer::updateLocForMacroArgTokens(SourceLocation ArgIdSpellLoc,
1069 Token *begin_tokens,
1070 Token *end_tokens) {
1071 SourceManager &SM = PP.getSourceManager();
1072
1073 SourceLocation ExpandLoc =
1074 getExpansionLocForMacroDefLoc(loc: ArgIdSpellLoc);
1075
1076 while (begin_tokens < end_tokens) {
1077 // If there's only one token just create a SLocEntry for it.
1078 if (end_tokens - begin_tokens == 1) {
1079 Token &Tok = *begin_tokens;
1080 Tok.setLocation(SM.createMacroArgExpansionLoc(SpellingLoc: Tok.getLocation(),
1081 ExpansionLoc: ExpandLoc,
1082 Length: Tok.getLength()));
1083 return;
1084 }
1085
1086 updateConsecutiveMacroArgTokens(SM, ExpandLoc, begin_tokens, end_tokens);
1087 }
1088}
1089
1090void TokenLexer::PropagateLineStartLeadingSpaceInfo(Token &Result) {
1091 AtStartOfLine = Result.isAtStartOfLine();
1092 HasLeadingSpace = Result.hasLeadingSpace();
1093}
1094

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