clang 17.0.0git
PPExpressions.cpp
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1//===--- PPExpressions.cpp - Preprocessor Expression Evaluation -----------===//
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 Preprocessor::EvaluateDirectiveExpression method,
10// which parses and evaluates integer constant expressions for #if directives.
11//
12//===----------------------------------------------------------------------===//
13//
14// FIXME: implement testing for #assert's.
15//
16//===----------------------------------------------------------------------===//
17
26#include "clang/Lex/MacroInfo.h"
29#include "clang/Lex/Token.h"
30#include "llvm/ADT/APSInt.h"
31#include "llvm/ADT/STLExtras.h"
32#include "llvm/ADT/SmallString.h"
33#include "llvm/ADT/StringExtras.h"
34#include "llvm/ADT/StringRef.h"
35#include "llvm/Support/ErrorHandling.h"
36#include "llvm/Support/SaveAndRestore.h"
37#include <cassert>
38
39using namespace clang;
40
41namespace {
42
43/// PPValue - Represents the value of a subexpression of a preprocessor
44/// conditional and the source range covered by it.
45class PPValue {
48
49public:
50 llvm::APSInt Val;
51
52 // Default ctor - Construct an 'invalid' PPValue.
53 PPValue(unsigned BitWidth) : Val(BitWidth) {}
54
55 // If this value was produced by directly evaluating an identifier, produce
56 // that identifier.
57 IdentifierInfo *getIdentifier() const { return II; }
58 void setIdentifier(IdentifierInfo *II) { this->II = II; }
59
60 unsigned getBitWidth() const { return Val.getBitWidth(); }
61 bool isUnsigned() const { return Val.isUnsigned(); }
62
63 SourceRange getRange() const { return Range; }
64
65 void setRange(SourceLocation L) { Range.setBegin(L); Range.setEnd(L); }
66 void setRange(SourceLocation B, SourceLocation E) {
67 Range.setBegin(B); Range.setEnd(E);
68 }
69 void setBegin(SourceLocation L) { Range.setBegin(L); }
70 void setEnd(SourceLocation L) { Range.setEnd(L); }
71};
72
73} // end anonymous namespace
74
75static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
76 Token &PeekTok, bool ValueLive,
77 bool &IncludedUndefinedIds,
78 Preprocessor &PP);
79
80/// DefinedTracker - This struct is used while parsing expressions to keep track
81/// of whether !defined(X) has been seen.
82///
83/// With this simple scheme, we handle the basic forms:
84/// !defined(X) and !defined X
85/// but we also trivially handle (silly) stuff like:
86/// !!!defined(X) and +!defined(X) and !+!+!defined(X) and !(defined(X)).
88 /// Each time a Value is evaluated, it returns information about whether the
89 /// parsed value is of the form defined(X), !defined(X) or is something else.
91 DefinedMacro, // defined(X)
92 NotDefinedMacro, // !defined(X)
93 Unknown // Something else.
95 /// TheMacro - When the state is DefinedMacro or NotDefinedMacro, this
96 /// indicates the macro that was checked.
99};
100
101/// EvaluateDefined - Process a 'defined(sym)' expression.
102static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
103 bool ValueLive, Preprocessor &PP) {
104 SourceLocation beginLoc(PeekTok.getLocation());
105 Result.setBegin(beginLoc);
106
107 // Get the next token, don't expand it.
108 PP.LexUnexpandedNonComment(PeekTok);
109
110 // Two options, it can either be a pp-identifier or a (.
111 SourceLocation LParenLoc;
112 if (PeekTok.is(tok::l_paren)) {
113 // Found a paren, remember we saw it and skip it.
114 LParenLoc = PeekTok.getLocation();
115 PP.LexUnexpandedNonComment(PeekTok);
116 }
117
118 if (PeekTok.is(tok::code_completion)) {
122 PP.LexUnexpandedNonComment(PeekTok);
123 }
124
125 // If we don't have a pp-identifier now, this is an error.
126 if (PP.CheckMacroName(PeekTok, MU_Other))
127 return true;
128
129 // Otherwise, we got an identifier, is it defined to something?
130 IdentifierInfo *II = PeekTok.getIdentifierInfo();
131 MacroDefinition Macro = PP.getMacroDefinition(II);
132 Result.Val = !!Macro;
133 Result.Val.setIsUnsigned(false); // Result is signed intmax_t.
134 DT.IncludedUndefinedIds = !Macro;
135
136 PP.emitMacroExpansionWarnings(PeekTok);
137
138 // If there is a macro, mark it used.
139 if (Result.Val != 0 && ValueLive)
140 PP.markMacroAsUsed(Macro.getMacroInfo());
141
142 // Save macro token for callback.
143 Token macroToken(PeekTok);
144
145 // If we are in parens, ensure we have a trailing ).
146 if (LParenLoc.isValid()) {
147 // Consume identifier.
148 Result.setEnd(PeekTok.getLocation());
149 PP.LexUnexpandedNonComment(PeekTok);
150
151 if (PeekTok.isNot(tok::r_paren)) {
152 PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_after)
153 << "'defined'" << tok::r_paren;
154 PP.Diag(LParenLoc, diag::note_matching) << tok::l_paren;
155 return true;
156 }
157 // Consume the ).
158 PP.LexNonComment(PeekTok);
159 Result.setEnd(PeekTok.getLocation());
160 } else {
161 // Consume identifier.
162 Result.setEnd(PeekTok.getLocation());
163 PP.LexNonComment(PeekTok);
164 }
165
166 // [cpp.cond]p4:
167 // Prior to evaluation, macro invocations in the list of preprocessing
168 // tokens that will become the controlling constant expression are replaced
169 // (except for those macro names modified by the 'defined' unary operator),
170 // just as in normal text. If the token 'defined' is generated as a result
171 // of this replacement process or use of the 'defined' unary operator does
172 // not match one of the two specified forms prior to macro replacement, the
173 // behavior is undefined.
174 // This isn't an idle threat, consider this program:
175 // #define FOO
176 // #define BAR defined(FOO)
177 // #if BAR
178 // ...
179 // #else
180 // ...
181 // #endif
182 // clang and gcc will pick the #if branch while Visual Studio will take the
183 // #else branch. Emit a warning about this undefined behavior.
184 if (beginLoc.isMacroID()) {
185 bool IsFunctionTypeMacro =
188 .getExpansion()
190 // For object-type macros, it's easy to replace
191 // #define FOO defined(BAR)
192 // with
193 // #if defined(BAR)
194 // #define FOO 1
195 // #else
196 // #define FOO 0
197 // #endif
198 // and doing so makes sense since compilers handle this differently in
199 // practice (see example further up). But for function-type macros,
200 // there is no good way to write
201 // # define FOO(x) (defined(M_ ## x) && M_ ## x)
202 // in a different way, and compilers seem to agree on how to behave here.
203 // So warn by default on object-type macros, but only warn in -pedantic
204 // mode on function-type macros.
205 if (IsFunctionTypeMacro)
206 PP.Diag(beginLoc, diag::warn_defined_in_function_type_macro);
207 else
208 PP.Diag(beginLoc, diag::warn_defined_in_object_type_macro);
209 }
210
211 // Invoke the 'defined' callback.
212 if (PPCallbacks *Callbacks = PP.getPPCallbacks()) {
213 Callbacks->Defined(macroToken, Macro,
214 SourceRange(beginLoc, PeekTok.getLocation()));
215 }
216
217 // Success, remember that we saw defined(X).
219 DT.TheMacro = II;
220 return false;
221}
222
223/// EvaluateValue - Evaluate the token PeekTok (and any others needed) and
224/// return the computed value in Result. Return true if there was an error
225/// parsing. This function also returns information about the form of the
226/// expression in DT. See above for information on what DT means.
227///
228/// If ValueLive is false, then this value is being evaluated in a context where
229/// the result is not used. As such, avoid diagnostics that relate to
230/// evaluation.
231static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
232 bool ValueLive, Preprocessor &PP) {
234
235 Result.setIdentifier(nullptr);
236
237 if (PeekTok.is(tok::code_completion)) {
241 PP.LexNonComment(PeekTok);
242 }
243
244 switch (PeekTok.getKind()) {
245 default:
246 // If this token's spelling is a pp-identifier, check to see if it is
247 // 'defined' or if it is a macro. Note that we check here because many
248 // keywords are pp-identifiers, so we can't check the kind.
249 if (IdentifierInfo *II = PeekTok.getIdentifierInfo()) {
250 // Handle "defined X" and "defined(X)".
251 if (II->isStr("defined"))
252 return EvaluateDefined(Result, PeekTok, DT, ValueLive, PP);
253
254 if (!II->isCPlusPlusOperatorKeyword()) {
255 // If this identifier isn't 'defined' or one of the special
256 // preprocessor keywords and it wasn't macro expanded, it turns
257 // into a simple 0
258 if (ValueLive) {
259 PP.Diag(PeekTok, diag::warn_pp_undef_identifier) << II;
260
261 const DiagnosticsEngine &DiagEngine = PP.getDiagnostics();
262 // If 'Wundef' is enabled, do not emit 'undef-prefix' diagnostics.
263 if (DiagEngine.isIgnored(diag::warn_pp_undef_identifier,
264 PeekTok.getLocation())) {
265 const std::vector<std::string> UndefPrefixes =
267 const StringRef IdentifierName = II->getName();
268 if (llvm::any_of(UndefPrefixes,
269 [&IdentifierName](const std::string &Prefix) {
270 return IdentifierName.startswith(Prefix);
271 }))
272 PP.Diag(PeekTok, diag::warn_pp_undef_prefix)
273 << AddFlagValue{llvm::join(UndefPrefixes, ",")} << II;
274 }
275 }
276 Result.Val = 0;
277 Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0.
278 Result.setIdentifier(II);
279 Result.setRange(PeekTok.getLocation());
280 DT.IncludedUndefinedIds = true;
281 PP.LexNonComment(PeekTok);
282 return false;
283 }
284 }
285 PP.Diag(PeekTok, diag::err_pp_expr_bad_token_start_expr);
286 return true;
287 case tok::eod:
288 case tok::r_paren:
289 // If there is no expression, report and exit.
290 PP.Diag(PeekTok, diag::err_pp_expected_value_in_expr);
291 return true;
292 case tok::numeric_constant: {
293 SmallString<64> IntegerBuffer;
294 bool NumberInvalid = false;
295 StringRef Spelling = PP.getSpelling(PeekTok, IntegerBuffer,
296 &NumberInvalid);
297 if (NumberInvalid)
298 return true; // a diagnostic was already reported
299
300 NumericLiteralParser Literal(Spelling, PeekTok.getLocation(),
301 PP.getSourceManager(), PP.getLangOpts(),
302 PP.getTargetInfo(), PP.getDiagnostics());
303 if (Literal.hadError)
304 return true; // a diagnostic was already reported.
305
306 if (Literal.isFloatingLiteral() || Literal.isImaginary) {
307 PP.Diag(PeekTok, diag::err_pp_illegal_floating_literal);
308 return true;
309 }
310 assert(Literal.isIntegerLiteral() && "Unknown ppnumber");
311
312 // Complain about, and drop, any ud-suffix.
313 if (Literal.hasUDSuffix())
314 PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*integer*/1;
315
316 // 'long long' is a C99 or C++11 feature.
317 if (!PP.getLangOpts().C99 && Literal.isLongLong) {
318 if (PP.getLangOpts().CPlusPlus)
319 PP.Diag(PeekTok,
320 PP.getLangOpts().CPlusPlus11 ?
321 diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong);
322 else
323 PP.Diag(PeekTok, diag::ext_c99_longlong);
324 }
325
326 // 'z/uz' literals are a C++23 feature.
327 if (Literal.isSizeT)
328 PP.Diag(PeekTok, PP.getLangOpts().CPlusPlus
329 ? PP.getLangOpts().CPlusPlus23
330 ? diag::warn_cxx20_compat_size_t_suffix
331 : diag::ext_cxx23_size_t_suffix
332 : diag::err_cxx23_size_t_suffix);
333
334 // 'wb/uwb' literals are a C2x feature. We explicitly do not support the
335 // suffix in C++ as an extension because a library-based UDL that resolves
336 // to a library type may be more appropriate there.
337 if (Literal.isBitInt)
338 PP.Diag(PeekTok, PP.getLangOpts().C2x
339 ? diag::warn_c2x_compat_bitint_suffix
340 : diag::ext_c2x_bitint_suffix);
341
342 // Parse the integer literal into Result.
343 if (Literal.GetIntegerValue(Result.Val)) {
344 // Overflow parsing integer literal.
345 if (ValueLive)
346 PP.Diag(PeekTok, diag::err_integer_literal_too_large)
347 << /* Unsigned */ 1;
348 Result.Val.setIsUnsigned(true);
349 } else {
350 // Set the signedness of the result to match whether there was a U suffix
351 // or not.
352 Result.Val.setIsUnsigned(Literal.isUnsigned);
353
354 // Detect overflow based on whether the value is signed. If signed
355 // and if the value is too large, emit a warning "integer constant is so
356 // large that it is unsigned" e.g. on 12345678901234567890 where intmax_t
357 // is 64-bits.
358 if (!Literal.isUnsigned && Result.Val.isNegative()) {
359 // Octal, hexadecimal, and binary literals are implicitly unsigned if
360 // the value does not fit into a signed integer type.
361 if (ValueLive && Literal.getRadix() == 10)
362 PP.Diag(PeekTok, diag::ext_integer_literal_too_large_for_signed);
363 Result.Val.setIsUnsigned(true);
364 }
365 }
366
367 // Consume the token.
368 Result.setRange(PeekTok.getLocation());
369 PP.LexNonComment(PeekTok);
370 return false;
371 }
372 case tok::char_constant: // 'x'
373 case tok::wide_char_constant: // L'x'
374 case tok::utf8_char_constant: // u8'x'
375 case tok::utf16_char_constant: // u'x'
376 case tok::utf32_char_constant: { // U'x'
377 // Complain about, and drop, any ud-suffix.
378 if (PeekTok.hasUDSuffix())
379 PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*character*/0;
380
381 SmallString<32> CharBuffer;
382 bool CharInvalid = false;
383 StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid);
384 if (CharInvalid)
385 return true;
386
387 CharLiteralParser Literal(ThisTok.begin(), ThisTok.end(),
388 PeekTok.getLocation(), PP, PeekTok.getKind());
389 if (Literal.hadError())
390 return true; // A diagnostic was already emitted.
391
392 // Character literals are always int or wchar_t, expand to intmax_t.
393 const TargetInfo &TI = PP.getTargetInfo();
394 unsigned NumBits;
395 if (Literal.isMultiChar())
396 NumBits = TI.getIntWidth();
397 else if (Literal.isWide())
398 NumBits = TI.getWCharWidth();
399 else if (Literal.isUTF16())
400 NumBits = TI.getChar16Width();
401 else if (Literal.isUTF32())
402 NumBits = TI.getChar32Width();
403 else // char or char8_t
404 NumBits = TI.getCharWidth();
405
406 // Set the width.
407 llvm::APSInt Val(NumBits);
408 // Set the value.
409 Val = Literal.getValue();
410 // Set the signedness. UTF-16 and UTF-32 are always unsigned
411 // UTF-8 is unsigned if -fchar8_t is specified.
412 if (Literal.isWide())
413 Val.setIsUnsigned(!TargetInfo::isTypeSigned(TI.getWCharType()));
414 else if (Literal.isUTF16() || Literal.isUTF32())
415 Val.setIsUnsigned(true);
416 else if (Literal.isUTF8()) {
417 if (PP.getLangOpts().CPlusPlus)
418 Val.setIsUnsigned(
419 PP.getLangOpts().Char8 ? true : !PP.getLangOpts().CharIsSigned);
420 else
421 Val.setIsUnsigned(true);
422 } else
423 Val.setIsUnsigned(!PP.getLangOpts().CharIsSigned);
424
425 if (Result.Val.getBitWidth() > Val.getBitWidth()) {
426 Result.Val = Val.extend(Result.Val.getBitWidth());
427 } else {
428 assert(Result.Val.getBitWidth() == Val.getBitWidth() &&
429 "intmax_t smaller than char/wchar_t?");
430 Result.Val = Val;
431 }
432
433 // Consume the token.
434 Result.setRange(PeekTok.getLocation());
435 PP.LexNonComment(PeekTok);
436 return false;
437 }
438 case tok::l_paren: {
439 SourceLocation Start = PeekTok.getLocation();
440 PP.LexNonComment(PeekTok); // Eat the (.
441 // Parse the value and if there are any binary operators involved, parse
442 // them.
443 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
444
445 // If this is a silly value like (X), which doesn't need parens, check for
446 // !(defined X).
447 if (PeekTok.is(tok::r_paren)) {
448 // Just use DT unmodified as our result.
449 } else {
450 // Otherwise, we have something like (x+y), and we consumed '(x'.
451 if (EvaluateDirectiveSubExpr(Result, 1, PeekTok, ValueLive,
452 DT.IncludedUndefinedIds, PP))
453 return true;
454
455 if (PeekTok.isNot(tok::r_paren)) {
456 PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_rparen)
457 << Result.getRange();
458 PP.Diag(Start, diag::note_matching) << tok::l_paren;
459 return true;
460 }
462 }
463 Result.setRange(Start, PeekTok.getLocation());
464 Result.setIdentifier(nullptr);
465 PP.LexNonComment(PeekTok); // Eat the ).
466 return false;
467 }
468 case tok::plus: {
469 SourceLocation Start = PeekTok.getLocation();
470 // Unary plus doesn't modify the value.
471 PP.LexNonComment(PeekTok);
472 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
473 Result.setBegin(Start);
474 Result.setIdentifier(nullptr);
475 return false;
476 }
477 case tok::minus: {
478 SourceLocation Loc = PeekTok.getLocation();
479 PP.LexNonComment(PeekTok);
480 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
481 Result.setBegin(Loc);
482 Result.setIdentifier(nullptr);
483
484 // C99 6.5.3.3p3: The sign of the result matches the sign of the operand.
485 Result.Val = -Result.Val;
486
487 // -MININT is the only thing that overflows. Unsigned never overflows.
488 bool Overflow = !Result.isUnsigned() && Result.Val.isMinSignedValue();
489
490 // If this operator is live and overflowed, report the issue.
491 if (Overflow && ValueLive)
492 PP.Diag(Loc, diag::warn_pp_expr_overflow) << Result.getRange();
493
495 return false;
496 }
497
498 case tok::tilde: {
499 SourceLocation Start = PeekTok.getLocation();
500 PP.LexNonComment(PeekTok);
501 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
502 Result.setBegin(Start);
503 Result.setIdentifier(nullptr);
504
505 // C99 6.5.3.3p4: The sign of the result matches the sign of the operand.
506 Result.Val = ~Result.Val;
508 return false;
509 }
510
511 case tok::exclaim: {
512 SourceLocation Start = PeekTok.getLocation();
513 PP.LexNonComment(PeekTok);
514 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
515 Result.setBegin(Start);
516 Result.Val = !Result.Val;
517 // C99 6.5.3.3p5: The sign of the result is 'int', aka it is signed.
518 Result.Val.setIsUnsigned(false);
519 Result.setIdentifier(nullptr);
520
525 return false;
526 }
527 case tok::kw_true:
528 case tok::kw_false:
529 Result.Val = PeekTok.getKind() == tok::kw_true;
530 Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0.
531 Result.setIdentifier(PeekTok.getIdentifierInfo());
532 Result.setRange(PeekTok.getLocation());
533 PP.LexNonComment(PeekTok);
534 return false;
535
536 // FIXME: Handle #assert
537 }
538}
539
540/// getPrecedence - Return the precedence of the specified binary operator
541/// token. This returns:
542/// ~0 - Invalid token.
543/// 14 -> 3 - various operators.
544/// 0 - 'eod' or ')'
545static unsigned getPrecedence(tok::TokenKind Kind) {
546 switch (Kind) {
547 default: return ~0U;
548 case tok::percent:
549 case tok::slash:
550 case tok::star: return 14;
551 case tok::plus:
552 case tok::minus: return 13;
553 case tok::lessless:
554 case tok::greatergreater: return 12;
555 case tok::lessequal:
556 case tok::less:
557 case tok::greaterequal:
558 case tok::greater: return 11;
559 case tok::exclaimequal:
560 case tok::equalequal: return 10;
561 case tok::amp: return 9;
562 case tok::caret: return 8;
563 case tok::pipe: return 7;
564 case tok::ampamp: return 6;
565 case tok::pipepipe: return 5;
566 case tok::question: return 4;
567 case tok::comma: return 3;
568 case tok::colon: return 2;
569 case tok::r_paren: return 0;// Lowest priority, end of expr.
570 case tok::eod: return 0;// Lowest priority, end of directive.
571 }
572}
573
574static void diagnoseUnexpectedOperator(Preprocessor &PP, PPValue &LHS,
575 Token &Tok) {
576 if (Tok.is(tok::l_paren) && LHS.getIdentifier())
577 PP.Diag(LHS.getRange().getBegin(), diag::err_pp_expr_bad_token_lparen)
578 << LHS.getIdentifier();
579 else
580 PP.Diag(Tok.getLocation(), diag::err_pp_expr_bad_token_binop)
581 << LHS.getRange();
582}
583
584/// EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is
585/// PeekTok, and whose precedence is PeekPrec. This returns the result in LHS.
586///
587/// If ValueLive is false, then this value is being evaluated in a context where
588/// the result is not used. As such, avoid diagnostics that relate to
589/// evaluation, such as division by zero warnings.
590static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
591 Token &PeekTok, bool ValueLive,
592 bool &IncludedUndefinedIds,
593 Preprocessor &PP) {
594 unsigned PeekPrec = getPrecedence(PeekTok.getKind());
595 // If this token isn't valid, report the error.
596 if (PeekPrec == ~0U) {
597 diagnoseUnexpectedOperator(PP, LHS, PeekTok);
598 return true;
599 }
600
601 while (true) {
602 // If this token has a lower precedence than we are allowed to parse, return
603 // it so that higher levels of the recursion can parse it.
604 if (PeekPrec < MinPrec)
605 return false;
606
607 tok::TokenKind Operator = PeekTok.getKind();
608
609 // If this is a short-circuiting operator, see if the RHS of the operator is
610 // dead. Note that this cannot just clobber ValueLive. Consider
611 // "0 && 1 ? 4 : 1 / 0", which is parsed as "(0 && 1) ? 4 : (1 / 0)". In
612 // this example, the RHS of the && being dead does not make the rest of the
613 // expr dead.
614 bool RHSIsLive;
615 if (Operator == tok::ampamp && LHS.Val == 0)
616 RHSIsLive = false; // RHS of "0 && x" is dead.
617 else if (Operator == tok::pipepipe && LHS.Val != 0)
618 RHSIsLive = false; // RHS of "1 || x" is dead.
619 else if (Operator == tok::question && LHS.Val == 0)
620 RHSIsLive = false; // RHS (x) of "0 ? x : y" is dead.
621 else
622 RHSIsLive = ValueLive;
623
624 // Consume the operator, remembering the operator's location for reporting.
625 SourceLocation OpLoc = PeekTok.getLocation();
626 PP.LexNonComment(PeekTok);
627
628 PPValue RHS(LHS.getBitWidth());
629 // Parse the RHS of the operator.
631 if (EvaluateValue(RHS, PeekTok, DT, RHSIsLive, PP)) return true;
632 IncludedUndefinedIds = DT.IncludedUndefinedIds;
633
634 // Remember the precedence of this operator and get the precedence of the
635 // operator immediately to the right of the RHS.
636 unsigned ThisPrec = PeekPrec;
637 PeekPrec = getPrecedence(PeekTok.getKind());
638
639 // If this token isn't valid, report the error.
640 if (PeekPrec == ~0U) {
641 diagnoseUnexpectedOperator(PP, RHS, PeekTok);
642 return true;
643 }
644
645 // Decide whether to include the next binop in this subexpression. For
646 // example, when parsing x+y*z and looking at '*', we want to recursively
647 // handle y*z as a single subexpression. We do this because the precedence
648 // of * is higher than that of +. The only strange case we have to handle
649 // here is for the ?: operator, where the precedence is actually lower than
650 // the LHS of the '?'. The grammar rule is:
651 //
652 // conditional-expression ::=
653 // logical-OR-expression ? expression : conditional-expression
654 // where 'expression' is actually comma-expression.
655 unsigned RHSPrec;
656 if (Operator == tok::question)
657 // The RHS of "?" should be maximally consumed as an expression.
658 RHSPrec = getPrecedence(tok::comma);
659 else // All others should munch while higher precedence.
660 RHSPrec = ThisPrec+1;
661
662 if (PeekPrec >= RHSPrec) {
663 if (EvaluateDirectiveSubExpr(RHS, RHSPrec, PeekTok, RHSIsLive,
664 IncludedUndefinedIds, PP))
665 return true;
666 PeekPrec = getPrecedence(PeekTok.getKind());
667 }
668 assert(PeekPrec <= ThisPrec && "Recursion didn't work!");
669
670 // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if
671 // either operand is unsigned.
672 llvm::APSInt Res(LHS.getBitWidth());
673 switch (Operator) {
674 case tok::question: // No UAC for x and y in "x ? y : z".
675 case tok::lessless: // Shift amount doesn't UAC with shift value.
676 case tok::greatergreater: // Shift amount doesn't UAC with shift value.
677 case tok::comma: // Comma operands are not subject to UACs.
678 case tok::pipepipe: // Logical || does not do UACs.
679 case tok::ampamp: // Logical && does not do UACs.
680 break; // No UAC
681 default:
682 Res.setIsUnsigned(LHS.isUnsigned() || RHS.isUnsigned());
683 // If this just promoted something from signed to unsigned, and if the
684 // value was negative, warn about it.
685 if (ValueLive && Res.isUnsigned()) {
686 if (!LHS.isUnsigned() && LHS.Val.isNegative())
687 PP.Diag(OpLoc, diag::warn_pp_convert_to_positive) << 0
688 << toString(LHS.Val, 10, true) + " to " +
689 toString(LHS.Val, 10, false)
690 << LHS.getRange() << RHS.getRange();
691 if (!RHS.isUnsigned() && RHS.Val.isNegative())
692 PP.Diag(OpLoc, diag::warn_pp_convert_to_positive) << 1
693 << toString(RHS.Val, 10, true) + " to " +
694 toString(RHS.Val, 10, false)
695 << LHS.getRange() << RHS.getRange();
696 }
697 LHS.Val.setIsUnsigned(Res.isUnsigned());
698 RHS.Val.setIsUnsigned(Res.isUnsigned());
699 }
700
701 bool Overflow = false;
702 switch (Operator) {
703 default: llvm_unreachable("Unknown operator token!");
704 case tok::percent:
705 if (RHS.Val != 0)
706 Res = LHS.Val % RHS.Val;
707 else if (ValueLive) {
708 PP.Diag(OpLoc, diag::err_pp_remainder_by_zero)
709 << LHS.getRange() << RHS.getRange();
710 return true;
711 }
712 break;
713 case tok::slash:
714 if (RHS.Val != 0) {
715 if (LHS.Val.isSigned())
716 Res = llvm::APSInt(LHS.Val.sdiv_ov(RHS.Val, Overflow), false);
717 else
718 Res = LHS.Val / RHS.Val;
719 } else if (ValueLive) {
720 PP.Diag(OpLoc, diag::err_pp_division_by_zero)
721 << LHS.getRange() << RHS.getRange();
722 return true;
723 }
724 break;
725
726 case tok::star:
727 if (Res.isSigned())
728 Res = llvm::APSInt(LHS.Val.smul_ov(RHS.Val, Overflow), false);
729 else
730 Res = LHS.Val * RHS.Val;
731 break;
732 case tok::lessless: {
733 // Determine whether overflow is about to happen.
734 if (LHS.isUnsigned())
735 Res = LHS.Val.ushl_ov(RHS.Val, Overflow);
736 else
737 Res = llvm::APSInt(LHS.Val.sshl_ov(RHS.Val, Overflow), false);
738 break;
739 }
740 case tok::greatergreater: {
741 // Determine whether overflow is about to happen.
742 unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue());
743 if (ShAmt >= LHS.getBitWidth()) {
744 Overflow = true;
745 ShAmt = LHS.getBitWidth()-1;
746 }
747 Res = LHS.Val >> ShAmt;
748 break;
749 }
750 case tok::plus:
751 if (LHS.isUnsigned())
752 Res = LHS.Val + RHS.Val;
753 else
754 Res = llvm::APSInt(LHS.Val.sadd_ov(RHS.Val, Overflow), false);
755 break;
756 case tok::minus:
757 if (LHS.isUnsigned())
758 Res = LHS.Val - RHS.Val;
759 else
760 Res = llvm::APSInt(LHS.Val.ssub_ov(RHS.Val, Overflow), false);
761 break;
762 case tok::lessequal:
763 Res = LHS.Val <= RHS.Val;
764 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
765 break;
766 case tok::less:
767 Res = LHS.Val < RHS.Val;
768 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
769 break;
770 case tok::greaterequal:
771 Res = LHS.Val >= RHS.Val;
772 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
773 break;
774 case tok::greater:
775 Res = LHS.Val > RHS.Val;
776 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
777 break;
778 case tok::exclaimequal:
779 Res = LHS.Val != RHS.Val;
780 Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed)
781 break;
782 case tok::equalequal:
783 Res = LHS.Val == RHS.Val;
784 Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed)
785 break;
786 case tok::amp:
787 Res = LHS.Val & RHS.Val;
788 break;
789 case tok::caret:
790 Res = LHS.Val ^ RHS.Val;
791 break;
792 case tok::pipe:
793 Res = LHS.Val | RHS.Val;
794 break;
795 case tok::ampamp:
796 Res = (LHS.Val != 0 && RHS.Val != 0);
797 Res.setIsUnsigned(false); // C99 6.5.13p3, result is always int (signed)
798 break;
799 case tok::pipepipe:
800 Res = (LHS.Val != 0 || RHS.Val != 0);
801 Res.setIsUnsigned(false); // C99 6.5.14p3, result is always int (signed)
802 break;
803 case tok::comma:
804 // Comma is invalid in pp expressions in c89/c++ mode, but is valid in C99
805 // if not being evaluated.
806 if (!PP.getLangOpts().C99 || ValueLive)
807 PP.Diag(OpLoc, diag::ext_pp_comma_expr)
808 << LHS.getRange() << RHS.getRange();
809 Res = RHS.Val; // LHS = LHS,RHS -> RHS.
810 break;
811 case tok::question: {
812 // Parse the : part of the expression.
813 if (PeekTok.isNot(tok::colon)) {
814 PP.Diag(PeekTok.getLocation(), diag::err_expected)
815 << tok::colon << LHS.getRange() << RHS.getRange();
816 PP.Diag(OpLoc, diag::note_matching) << tok::question;
817 return true;
818 }
819 // Consume the :.
820 PP.LexNonComment(PeekTok);
821
822 // Evaluate the value after the :.
823 bool AfterColonLive = ValueLive && LHS.Val == 0;
824 PPValue AfterColonVal(LHS.getBitWidth());
826 if (EvaluateValue(AfterColonVal, PeekTok, DT, AfterColonLive, PP))
827 return true;
828
829 // Parse anything after the : with the same precedence as ?. We allow
830 // things of equal precedence because ?: is right associative.
831 if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec,
832 PeekTok, AfterColonLive,
833 IncludedUndefinedIds, PP))
834 return true;
835
836 // Now that we have the condition, the LHS and the RHS of the :, evaluate.
837 Res = LHS.Val != 0 ? RHS.Val : AfterColonVal.Val;
838 RHS.setEnd(AfterColonVal.getRange().getEnd());
839
840 // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if
841 // either operand is unsigned.
842 Res.setIsUnsigned(RHS.isUnsigned() || AfterColonVal.isUnsigned());
843
844 // Figure out the precedence of the token after the : part.
845 PeekPrec = getPrecedence(PeekTok.getKind());
846 break;
847 }
848 case tok::colon:
849 // Don't allow :'s to float around without being part of ?: exprs.
850 PP.Diag(OpLoc, diag::err_pp_colon_without_question)
851 << LHS.getRange() << RHS.getRange();
852 return true;
853 }
854
855 // If this operator is live and overflowed, report the issue.
856 if (Overflow && ValueLive)
857 PP.Diag(OpLoc, diag::warn_pp_expr_overflow)
858 << LHS.getRange() << RHS.getRange();
859
860 // Put the result back into 'LHS' for our next iteration.
861 LHS.Val = Res;
862 LHS.setEnd(RHS.getRange().getEnd());
863 RHS.setIdentifier(nullptr);
864 }
865}
866
867/// EvaluateDirectiveExpression - Evaluate an integer constant expression that
868/// may occur after a #if or #elif directive. If the expression is equivalent
869/// to "!defined(X)" return X in IfNDefMacro.
870Preprocessor::DirectiveEvalResult
871Preprocessor::EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro) {
872 SaveAndRestore PPDir(ParsingIfOrElifDirective, true);
873 // Save the current state of 'DisableMacroExpansion' and reset it to false. If
874 // 'DisableMacroExpansion' is true, then we must be in a macro argument list
875 // in which case a directive is undefined behavior. We want macros to be able
876 // to recursively expand in order to get more gcc-list behavior, so we force
877 // DisableMacroExpansion to false and restore it when we're done parsing the
878 // expression.
879 bool DisableMacroExpansionAtStartOfDirective = DisableMacroExpansion;
880 DisableMacroExpansion = false;
881
882 // Peek ahead one token.
883 Token Tok;
884 LexNonComment(Tok);
885
886 // C99 6.10.1p3 - All expressions are evaluated as intmax_t or uintmax_t.
887 unsigned BitWidth = getTargetInfo().getIntMaxTWidth();
888
889 PPValue ResVal(BitWidth);
891 SourceLocation ExprStartLoc = SourceMgr.getExpansionLoc(Tok.getLocation());
892 if (EvaluateValue(ResVal, Tok, DT, true, *this)) {
893 // Parse error, skip the rest of the macro line.
894 SourceRange ConditionRange = ExprStartLoc;
895 if (Tok.isNot(tok::eod))
896 ConditionRange = DiscardUntilEndOfDirective();
897
898 // Restore 'DisableMacroExpansion'.
899 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
900
901 // We cannot trust the source range from the value because there was a
902 // parse error. Track the range manually -- the end of the directive is the
903 // end of the condition range.
904 return {false,
906 {ExprStartLoc, ConditionRange.getEnd()}};
907 }
908
909 // If we are at the end of the expression after just parsing a value, there
910 // must be no (unparenthesized) binary operators involved, so we can exit
911 // directly.
912 if (Tok.is(tok::eod)) {
913 // If the expression we parsed was of the form !defined(macro), return the
914 // macro in IfNDefMacro.
916 IfNDefMacro = DT.TheMacro;
917
918 // Restore 'DisableMacroExpansion'.
919 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
920 return {ResVal.Val != 0, DT.IncludedUndefinedIds, ResVal.getRange()};
921 }
922
923 // Otherwise, we must have a binary operator (e.g. "#if 1 < 2"), so parse the
924 // operator and the stuff after it.
925 if (EvaluateDirectiveSubExpr(ResVal, getPrecedence(tok::question),
926 Tok, true, DT.IncludedUndefinedIds, *this)) {
927 // Parse error, skip the rest of the macro line.
928 if (Tok.isNot(tok::eod))
930
931 // Restore 'DisableMacroExpansion'.
932 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
933 return {false, DT.IncludedUndefinedIds, ResVal.getRange()};
934 }
935
936 // If we aren't at the tok::eod token, something bad happened, like an extra
937 // ')' token.
938 if (Tok.isNot(tok::eod)) {
939 Diag(Tok, diag::err_pp_expected_eol);
941 }
942
943 // Restore 'DisableMacroExpansion'.
944 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
945 return {ResVal.Val != 0, DT.IncludedUndefinedIds, ResVal.getRange()};
946}
Defines the clang::IdentifierInfo, clang::IdentifierTable, and clang::Selector interfaces.
Defines the clang::MacroInfo and clang::MacroDirective classes.
Defines the PPCallbacks interface.
static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT, bool ValueLive, Preprocessor &PP)
EvaluateValue - Evaluate the token PeekTok (and any others needed) and return the computed value in R...
static void diagnoseUnexpectedOperator(Preprocessor &PP, PPValue &LHS, Token &Tok)
static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, Token &PeekTok, bool ValueLive, bool &IncludedUndefinedIds, Preprocessor &PP)
EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is PeekTok,...
static unsigned getPrecedence(tok::TokenKind Kind)
getPrecedence - Return the precedence of the specified binary operator token.
static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT, bool ValueLive, Preprocessor &PP)
EvaluateDefined - Process a 'defined(sym)' expression.
static StringRef getIdentifier(const Token &Tok)
Defines the clang::Preprocessor interface.
static std::string toString(const clang::SanitizerSet &Sanitizers)
Produce a string containing comma-separated names of sanitizers in Sanitizers set.
static CharSourceRange getRange(const CharSourceRange &EditRange, const SourceManager &SM, const LangOptions &LangOpts, bool IncludeMacroExpansion)
Definition: SourceCode.cpp:104
Defines the clang::SourceLocation class and associated facilities.
Defines the SourceManager interface.
Defines the clang::TokenKind enum and support functions.
CharLiteralParser - Perform interpretation and semantic analysis of a character literal.
virtual void CodeCompleteMacroName(bool IsDefinition)
Callback invoked when performing code completion in a context where the name of a macro is expected.
virtual void CodeCompletePreprocessorExpression()
Callback invoked when performing code completion in a preprocessor expression, such as the condition ...
std::vector< std::string > UndefPrefixes
The list of prefixes from -Wundef-prefix=... used to generate warnings for undefined macros.
Concrete class used by the front-end to report problems and issues.
Definition: Diagnostic.h:192
DiagnosticOptions & getDiagnosticOptions() const
Retrieve the diagnostic options.
Definition: Diagnostic.h:557
bool isIgnored(unsigned DiagID, SourceLocation Loc) const
Determine whether the diagnostic is known to be ignored.
Definition: Diagnostic.h:911
One of these records is kept for each identifier that is lexed.
bool isCPlusPlusOperatorKeyword() const
bool isStr(const char(&Str)[StrLen]) const
Return true if this is the identifier for the specified string.
StringRef getName() const
Return the actual identifier string.
A description of the current definition of a macro.
Definition: MacroInfo.h:587
NumericLiteralParser - This performs strict semantic analysis of the content of a ppnumber,...
This interface provides a way to observe the actions of the preprocessor as it does its thing.
Definition: PPCallbacks.h:35
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:128
PPCallbacks * getPPCallbacks() const
void markMacroAsUsed(MacroInfo *MI)
A macro is used, update information about macros that need unused warnings.
void setCodeCompletionReached()
Note that we hit the code-completion point.
void LexNonComment(Token &Result)
Lex a token.
SourceManager & getSourceManager() const
MacroDefinition getMacroDefinition(const IdentifierInfo *II)
bool CheckMacroName(Token &MacroNameTok, MacroUse isDefineUndef, bool *ShadowFlag=nullptr)
void emitMacroExpansionWarnings(const Token &Identifier) const
const TargetInfo & getTargetInfo() const
void LexUnexpandedNonComment(Token &Result)
Like LexNonComment, but this disables macro expansion of identifier tokens.
StringRef getSpelling(SourceLocation loc, SmallVectorImpl< char > &buffer, bool *invalid=nullptr) const
Return the 'spelling' of the token at the given location; does not go up to the spelling location or ...
SourceRange DiscardUntilEndOfDirective()
Read and discard all tokens remaining on the current line until the tok::eod token is found.
CodeCompletionHandler * getCodeCompletionHandler() const
Retrieve the current code-completion handler.
const LangOptions & getLangOpts() const
DiagnosticsEngine & getDiagnostics() const
DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID) const
Forwarding function for diagnostics.
Encodes a location in the source.
bool isValid() const
Return true if this is a valid SourceLocation object.
FileID getFileID(SourceLocation SpellingLoc) const
Return the FileID for a SourceLocation.
SourceLocation getExpansionLoc(SourceLocation Loc) const
Given a SourceLocation object Loc, return the expansion location referenced by the ID.
const SrcMgr::SLocEntry & getSLocEntry(FileID FID, bool *Invalid=nullptr) const
A trivial tuple used to represent a source range.
SourceLocation getEnd() const
bool isFunctionMacroExpansion() const
const ExpansionInfo & getExpansion() const
Exposes information about the current target.
Definition: TargetInfo.h:206
unsigned getChar32Width() const
getChar32Width/Align - Return the size of 'char32_t' for this target, in bits.
Definition: TargetInfo.h:711
static bool isTypeSigned(IntType T)
Returns true if the type is signed; false otherwise.
Definition: TargetInfo.cpp:369
unsigned getChar16Width() const
getChar16Width/Align - Return the size of 'char16_t' for this target, in bits.
Definition: TargetInfo.h:706
unsigned getIntWidth() const
getIntWidth/Align - Return the size of 'signed int' and 'unsigned int' for this target,...
Definition: TargetInfo.h:480
IntType getWCharType() const
Definition: TargetInfo.h:372
unsigned getWCharWidth() const
getWCharWidth/Align - Return the size of 'wchar_t' for this target, in bits.
Definition: TargetInfo.h:701
unsigned getIntMaxTWidth() const
Return the size of intmax_t and uintmax_t for this target, in bits.
Definition: TargetInfo.h:822
unsigned getCharWidth() const
Definition: TargetInfo.h:467
Token - This structure provides full information about a lexed token.
Definition: Token.h:35
IdentifierInfo * getIdentifierInfo() const
Definition: Token.h:186
SourceLocation getLocation() const
Return a source location identifier for the specified offset in the current file.
Definition: Token.h:131
bool is(tok::TokenKind K) const
is/isNot - Predicates to check if this token is a specific kind, as in "if (Tok.is(tok::l_brace)) {....
Definition: Token.h:98
tok::TokenKind getKind() const
Definition: Token.h:93
bool isNot(tok::TokenKind K) const
Definition: Token.h:99
bool hasUDSuffix() const
Return true if this token is a string or character literal which has a ud-suffix.
Definition: Token.h:300
Defines the clang::TargetInfo interface.
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:25
@ MU_Other
Definition: Preprocessor.h:113
DefinedTracker - This struct is used while parsing expressions to keep track of whether !...
TrackerState
Each time a Value is evaluated, it returns information about whether the parsed value is of the form ...
IdentifierInfo * TheMacro
TheMacro - When the state is DefinedMacro or NotDefinedMacro, this indicates the macro that was check...
enum DefinedTracker::TrackerState State