clang  9.0.0svn
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 
18 #include "clang/Lex/Preprocessor.h"
22 #include "clang/Basic/TargetInfo.h"
23 #include "clang/Basic/TokenKinds.h"
27 #include "clang/Lex/MacroInfo.h"
28 #include "clang/Lex/PPCallbacks.h"
29 #include "clang/Lex/Token.h"
30 #include "llvm/ADT/APSInt.h"
31 #include "llvm/ADT/SmallString.h"
32 #include "llvm/ADT/StringRef.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/SaveAndRestore.h"
35 #include <cassert>
36 
37 using namespace clang;
38 
39 namespace {
40 
41 /// PPValue - Represents the value of a subexpression of a preprocessor
42 /// conditional and the source range covered by it.
43 class PPValue {
44  SourceRange Range;
45  IdentifierInfo *II;
46 
47 public:
48  llvm::APSInt Val;
49 
50  // Default ctor - Construct an 'invalid' PPValue.
51  PPValue(unsigned BitWidth) : Val(BitWidth) {}
52 
53  // If this value was produced by directly evaluating an identifier, produce
54  // that identifier.
55  IdentifierInfo *getIdentifier() const { return II; }
56  void setIdentifier(IdentifierInfo *II) { this->II = II; }
57 
58  unsigned getBitWidth() const { return Val.getBitWidth(); }
59  bool isUnsigned() const { return Val.isUnsigned(); }
60 
61  SourceRange getRange() const { return Range; }
62 
63  void setRange(SourceLocation L) { Range.setBegin(L); Range.setEnd(L); }
64  void setRange(SourceLocation B, SourceLocation E) {
65  Range.setBegin(B); Range.setEnd(E);
66  }
67  void setBegin(SourceLocation L) { Range.setBegin(L); }
68  void setEnd(SourceLocation L) { Range.setEnd(L); }
69 };
70 
71 } // end anonymous namespace
72 
73 static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
74  Token &PeekTok, bool ValueLive,
75  bool &IncludedUndefinedIds,
76  Preprocessor &PP);
77 
78 /// DefinedTracker - This struct is used while parsing expressions to keep track
79 /// of whether !defined(X) has been seen.
80 ///
81 /// With this simple scheme, we handle the basic forms:
82 /// !defined(X) and !defined X
83 /// but we also trivially handle (silly) stuff like:
84 /// !!!defined(X) and +!defined(X) and !+!+!defined(X) and !(defined(X)).
86  /// Each time a Value is evaluated, it returns information about whether the
87  /// parsed value is of the form defined(X), !defined(X) or is something else.
88  enum TrackerState {
89  DefinedMacro, // defined(X)
90  NotDefinedMacro, // !defined(X)
91  Unknown // Something else.
92  } State;
93  /// TheMacro - When the state is DefinedMacro or NotDefinedMacro, this
94  /// indicates the macro that was checked.
96  bool IncludedUndefinedIds = false;
97 };
98 
99 /// EvaluateDefined - Process a 'defined(sym)' expression.
100 static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
101  bool ValueLive, Preprocessor &PP) {
102  SourceLocation beginLoc(PeekTok.getLocation());
103  Result.setBegin(beginLoc);
104 
105  // Get the next token, don't expand it.
106  PP.LexUnexpandedNonComment(PeekTok);
107 
108  // Two options, it can either be a pp-identifier or a (.
109  SourceLocation LParenLoc;
110  if (PeekTok.is(tok::l_paren)) {
111  // Found a paren, remember we saw it and skip it.
112  LParenLoc = PeekTok.getLocation();
113  PP.LexUnexpandedNonComment(PeekTok);
114  }
115 
116  if (PeekTok.is(tok::code_completion)) {
117  if (PP.getCodeCompletionHandler())
120  PP.LexUnexpandedNonComment(PeekTok);
121  }
122 
123  // If we don't have a pp-identifier now, this is an error.
124  if (PP.CheckMacroName(PeekTok, MU_Other))
125  return true;
126 
127  // Otherwise, we got an identifier, is it defined to something?
128  IdentifierInfo *II = PeekTok.getIdentifierInfo();
129  MacroDefinition Macro = PP.getMacroDefinition(II);
130  Result.Val = !!Macro;
131  Result.Val.setIsUnsigned(false); // Result is signed intmax_t.
132  DT.IncludedUndefinedIds = !Macro;
133 
134  // If there is a macro, mark it used.
135  if (Result.Val != 0 && ValueLive)
136  PP.markMacroAsUsed(Macro.getMacroInfo());
137 
138  // Save macro token for callback.
139  Token macroToken(PeekTok);
140 
141  // If we are in parens, ensure we have a trailing ).
142  if (LParenLoc.isValid()) {
143  // Consume identifier.
144  Result.setEnd(PeekTok.getLocation());
145  PP.LexUnexpandedNonComment(PeekTok);
146 
147  if (PeekTok.isNot(tok::r_paren)) {
148  PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_after)
149  << "'defined'" << tok::r_paren;
150  PP.Diag(LParenLoc, diag::note_matching) << tok::l_paren;
151  return true;
152  }
153  // Consume the ).
154  PP.LexNonComment(PeekTok);
155  Result.setEnd(PeekTok.getLocation());
156  } else {
157  // Consume identifier.
158  Result.setEnd(PeekTok.getLocation());
159  PP.LexNonComment(PeekTok);
160  }
161 
162  // [cpp.cond]p4:
163  // Prior to evaluation, macro invocations in the list of preprocessing
164  // tokens that will become the controlling constant expression are replaced
165  // (except for those macro names modified by the 'defined' unary operator),
166  // just as in normal text. If the token 'defined' is generated as a result
167  // of this replacement process or use of the 'defined' unary operator does
168  // not match one of the two specified forms prior to macro replacement, the
169  // behavior is undefined.
170  // This isn't an idle threat, consider this program:
171  // #define FOO
172  // #define BAR defined(FOO)
173  // #if BAR
174  // ...
175  // #else
176  // ...
177  // #endif
178  // clang and gcc will pick the #if branch while Visual Studio will take the
179  // #else branch. Emit a warning about this undefined behavior.
180  if (beginLoc.isMacroID()) {
181  bool IsFunctionTypeMacro =
182  PP.getSourceManager()
183  .getSLocEntry(PP.getSourceManager().getFileID(beginLoc))
184  .getExpansion()
185  .isFunctionMacroExpansion();
186  // For object-type macros, it's easy to replace
187  // #define FOO defined(BAR)
188  // with
189  // #if defined(BAR)
190  // #define FOO 1
191  // #else
192  // #define FOO 0
193  // #endif
194  // and doing so makes sense since compilers handle this differently in
195  // practice (see example further up). But for function-type macros,
196  // there is no good way to write
197  // # define FOO(x) (defined(M_ ## x) && M_ ## x)
198  // in a different way, and compilers seem to agree on how to behave here.
199  // So warn by default on object-type macros, but only warn in -pedantic
200  // mode on function-type macros.
201  if (IsFunctionTypeMacro)
202  PP.Diag(beginLoc, diag::warn_defined_in_function_type_macro);
203  else
204  PP.Diag(beginLoc, diag::warn_defined_in_object_type_macro);
205  }
206 
207  // Invoke the 'defined' callback.
208  if (PPCallbacks *Callbacks = PP.getPPCallbacks()) {
209  Callbacks->Defined(macroToken, Macro,
210  SourceRange(beginLoc, PeekTok.getLocation()));
211  }
212 
213  // Success, remember that we saw defined(X).
215  DT.TheMacro = II;
216  return false;
217 }
218 
219 /// EvaluateValue - Evaluate the token PeekTok (and any others needed) and
220 /// return the computed value in Result. Return true if there was an error
221 /// parsing. This function also returns information about the form of the
222 /// expression in DT. See above for information on what DT means.
223 ///
224 /// If ValueLive is false, then this value is being evaluated in a context where
225 /// the result is not used. As such, avoid diagnostics that relate to
226 /// evaluation.
227 static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
228  bool ValueLive, Preprocessor &PP) {
230 
231  Result.setIdentifier(nullptr);
232 
233  if (PeekTok.is(tok::code_completion)) {
234  if (PP.getCodeCompletionHandler())
237  PP.LexNonComment(PeekTok);
238  }
239 
240  switch (PeekTok.getKind()) {
241  default:
242  // If this token's spelling is a pp-identifier, check to see if it is
243  // 'defined' or if it is a macro. Note that we check here because many
244  // keywords are pp-identifiers, so we can't check the kind.
245  if (IdentifierInfo *II = PeekTok.getIdentifierInfo()) {
246  // Handle "defined X" and "defined(X)".
247  if (II->isStr("defined"))
248  return EvaluateDefined(Result, PeekTok, DT, ValueLive, PP);
249 
250  if (!II->isCPlusPlusOperatorKeyword()) {
251  // If this identifier isn't 'defined' or one of the special
252  // preprocessor keywords and it wasn't macro expanded, it turns
253  // into a simple 0
254  if (ValueLive)
255  PP.Diag(PeekTok, diag::warn_pp_undef_identifier) << II;
256  Result.Val = 0;
257  Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0.
258  Result.setIdentifier(II);
259  Result.setRange(PeekTok.getLocation());
260  DT.IncludedUndefinedIds = true;
261  PP.LexNonComment(PeekTok);
262  return false;
263  }
264  }
265  PP.Diag(PeekTok, diag::err_pp_expr_bad_token_start_expr);
266  return true;
267  case tok::eod:
268  case tok::r_paren:
269  // If there is no expression, report and exit.
270  PP.Diag(PeekTok, diag::err_pp_expected_value_in_expr);
271  return true;
272  case tok::numeric_constant: {
273  SmallString<64> IntegerBuffer;
274  bool NumberInvalid = false;
275  StringRef Spelling = PP.getSpelling(PeekTok, IntegerBuffer,
276  &NumberInvalid);
277  if (NumberInvalid)
278  return true; // a diagnostic was already reported
279 
280  NumericLiteralParser Literal(Spelling, PeekTok.getLocation(), PP);
281  if (Literal.hadError)
282  return true; // a diagnostic was already reported.
283 
284  if (Literal.isFloatingLiteral() || Literal.isImaginary) {
285  PP.Diag(PeekTok, diag::err_pp_illegal_floating_literal);
286  return true;
287  }
288  assert(Literal.isIntegerLiteral() && "Unknown ppnumber");
289 
290  // Complain about, and drop, any ud-suffix.
291  if (Literal.hasUDSuffix())
292  PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*integer*/1;
293 
294  // 'long long' is a C99 or C++11 feature.
295  if (!PP.getLangOpts().C99 && Literal.isLongLong) {
296  if (PP.getLangOpts().CPlusPlus)
297  PP.Diag(PeekTok,
298  PP.getLangOpts().CPlusPlus11 ?
299  diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong);
300  else
301  PP.Diag(PeekTok, diag::ext_c99_longlong);
302  }
303 
304  // Parse the integer literal into Result.
305  if (Literal.GetIntegerValue(Result.Val)) {
306  // Overflow parsing integer literal.
307  if (ValueLive)
308  PP.Diag(PeekTok, diag::err_integer_literal_too_large)
309  << /* Unsigned */ 1;
310  Result.Val.setIsUnsigned(true);
311  } else {
312  // Set the signedness of the result to match whether there was a U suffix
313  // or not.
314  Result.Val.setIsUnsigned(Literal.isUnsigned);
315 
316  // Detect overflow based on whether the value is signed. If signed
317  // and if the value is too large, emit a warning "integer constant is so
318  // large that it is unsigned" e.g. on 12345678901234567890 where intmax_t
319  // is 64-bits.
320  if (!Literal.isUnsigned && Result.Val.isNegative()) {
321  // Octal, hexadecimal, and binary literals are implicitly unsigned if
322  // the value does not fit into a signed integer type.
323  if (ValueLive && Literal.getRadix() == 10)
324  PP.Diag(PeekTok, diag::ext_integer_literal_too_large_for_signed);
325  Result.Val.setIsUnsigned(true);
326  }
327  }
328 
329  // Consume the token.
330  Result.setRange(PeekTok.getLocation());
331  PP.LexNonComment(PeekTok);
332  return false;
333  }
334  case tok::char_constant: // 'x'
335  case tok::wide_char_constant: // L'x'
336  case tok::utf8_char_constant: // u8'x'
337  case tok::utf16_char_constant: // u'x'
338  case tok::utf32_char_constant: { // U'x'
339  // Complain about, and drop, any ud-suffix.
340  if (PeekTok.hasUDSuffix())
341  PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*character*/0;
342 
343  SmallString<32> CharBuffer;
344  bool CharInvalid = false;
345  StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid);
346  if (CharInvalid)
347  return true;
348 
349  CharLiteralParser Literal(ThisTok.begin(), ThisTok.end(),
350  PeekTok.getLocation(), PP, PeekTok.getKind());
351  if (Literal.hadError())
352  return true; // A diagnostic was already emitted.
353 
354  // Character literals are always int or wchar_t, expand to intmax_t.
355  const TargetInfo &TI = PP.getTargetInfo();
356  unsigned NumBits;
357  if (Literal.isMultiChar())
358  NumBits = TI.getIntWidth();
359  else if (Literal.isWide())
360  NumBits = TI.getWCharWidth();
361  else if (Literal.isUTF16())
362  NumBits = TI.getChar16Width();
363  else if (Literal.isUTF32())
364  NumBits = TI.getChar32Width();
365  else // char or char8_t
366  NumBits = TI.getCharWidth();
367 
368  // Set the width.
369  llvm::APSInt Val(NumBits);
370  // Set the value.
371  Val = Literal.getValue();
372  // Set the signedness. UTF-16 and UTF-32 are always unsigned
373  if (Literal.isWide())
374  Val.setIsUnsigned(!TargetInfo::isTypeSigned(TI.getWCharType()));
375  else if (!Literal.isUTF16() && !Literal.isUTF32())
376  Val.setIsUnsigned(!PP.getLangOpts().CharIsSigned);
377 
378  if (Result.Val.getBitWidth() > Val.getBitWidth()) {
379  Result.Val = Val.extend(Result.Val.getBitWidth());
380  } else {
381  assert(Result.Val.getBitWidth() == Val.getBitWidth() &&
382  "intmax_t smaller than char/wchar_t?");
383  Result.Val = Val;
384  }
385 
386  // Consume the token.
387  Result.setRange(PeekTok.getLocation());
388  PP.LexNonComment(PeekTok);
389  return false;
390  }
391  case tok::l_paren: {
392  SourceLocation Start = PeekTok.getLocation();
393  PP.LexNonComment(PeekTok); // Eat the (.
394  // Parse the value and if there are any binary operators involved, parse
395  // them.
396  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
397 
398  // If this is a silly value like (X), which doesn't need parens, check for
399  // !(defined X).
400  if (PeekTok.is(tok::r_paren)) {
401  // Just use DT unmodified as our result.
402  } else {
403  // Otherwise, we have something like (x+y), and we consumed '(x'.
404  if (EvaluateDirectiveSubExpr(Result, 1, PeekTok, ValueLive,
405  DT.IncludedUndefinedIds, PP))
406  return true;
407 
408  if (PeekTok.isNot(tok::r_paren)) {
409  PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_rparen)
410  << Result.getRange();
411  PP.Diag(Start, diag::note_matching) << tok::l_paren;
412  return true;
413  }
415  }
416  Result.setRange(Start, PeekTok.getLocation());
417  Result.setIdentifier(nullptr);
418  PP.LexNonComment(PeekTok); // Eat the ).
419  return false;
420  }
421  case tok::plus: {
422  SourceLocation Start = PeekTok.getLocation();
423  // Unary plus doesn't modify the value.
424  PP.LexNonComment(PeekTok);
425  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
426  Result.setBegin(Start);
427  Result.setIdentifier(nullptr);
428  return false;
429  }
430  case tok::minus: {
431  SourceLocation Loc = PeekTok.getLocation();
432  PP.LexNonComment(PeekTok);
433  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
434  Result.setBegin(Loc);
435  Result.setIdentifier(nullptr);
436 
437  // C99 6.5.3.3p3: The sign of the result matches the sign of the operand.
438  Result.Val = -Result.Val;
439 
440  // -MININT is the only thing that overflows. Unsigned never overflows.
441  bool Overflow = !Result.isUnsigned() && Result.Val.isMinSignedValue();
442 
443  // If this operator is live and overflowed, report the issue.
444  if (Overflow && ValueLive)
445  PP.Diag(Loc, diag::warn_pp_expr_overflow) << Result.getRange();
446 
448  return false;
449  }
450 
451  case tok::tilde: {
452  SourceLocation Start = PeekTok.getLocation();
453  PP.LexNonComment(PeekTok);
454  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
455  Result.setBegin(Start);
456  Result.setIdentifier(nullptr);
457 
458  // C99 6.5.3.3p4: The sign of the result matches the sign of the operand.
459  Result.Val = ~Result.Val;
461  return false;
462  }
463 
464  case tok::exclaim: {
465  SourceLocation Start = PeekTok.getLocation();
466  PP.LexNonComment(PeekTok);
467  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
468  Result.setBegin(Start);
469  Result.Val = !Result.Val;
470  // C99 6.5.3.3p5: The sign of the result is 'int', aka it is signed.
471  Result.Val.setIsUnsigned(false);
472  Result.setIdentifier(nullptr);
473 
476  else if (DT.State == DefinedTracker::NotDefinedMacro)
478  return false;
479  }
480  case tok::kw_true:
481  case tok::kw_false:
482  Result.Val = PeekTok.getKind() == tok::kw_true;
483  Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0.
484  Result.setIdentifier(PeekTok.getIdentifierInfo());
485  Result.setRange(PeekTok.getLocation());
486  PP.LexNonComment(PeekTok);
487  return false;
488 
489  // FIXME: Handle #assert
490  }
491 }
492 
493 /// getPrecedence - Return the precedence of the specified binary operator
494 /// token. This returns:
495 /// ~0 - Invalid token.
496 /// 14 -> 3 - various operators.
497 /// 0 - 'eod' or ')'
499  switch (Kind) {
500  default: return ~0U;
501  case tok::percent:
502  case tok::slash:
503  case tok::star: return 14;
504  case tok::plus:
505  case tok::minus: return 13;
506  case tok::lessless:
507  case tok::greatergreater: return 12;
508  case tok::lessequal:
509  case tok::less:
510  case tok::greaterequal:
511  case tok::greater: return 11;
512  case tok::exclaimequal:
513  case tok::equalequal: return 10;
514  case tok::amp: return 9;
515  case tok::caret: return 8;
516  case tok::pipe: return 7;
517  case tok::ampamp: return 6;
518  case tok::pipepipe: return 5;
519  case tok::question: return 4;
520  case tok::comma: return 3;
521  case tok::colon: return 2;
522  case tok::r_paren: return 0;// Lowest priority, end of expr.
523  case tok::eod: return 0;// Lowest priority, end of directive.
524  }
525 }
526 
527 static void diagnoseUnexpectedOperator(Preprocessor &PP, PPValue &LHS,
528  Token &Tok) {
529  if (Tok.is(tok::l_paren) && LHS.getIdentifier())
530  PP.Diag(LHS.getRange().getBegin(), diag::err_pp_expr_bad_token_lparen)
531  << LHS.getIdentifier();
532  else
533  PP.Diag(Tok.getLocation(), diag::err_pp_expr_bad_token_binop)
534  << LHS.getRange();
535 }
536 
537 /// EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is
538 /// PeekTok, and whose precedence is PeekPrec. This returns the result in LHS.
539 ///
540 /// If ValueLive is false, then this value is being evaluated in a context where
541 /// the result is not used. As such, avoid diagnostics that relate to
542 /// evaluation, such as division by zero warnings.
543 static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
544  Token &PeekTok, bool ValueLive,
545  bool &IncludedUndefinedIds,
546  Preprocessor &PP) {
547  unsigned PeekPrec = getPrecedence(PeekTok.getKind());
548  // If this token isn't valid, report the error.
549  if (PeekPrec == ~0U) {
550  diagnoseUnexpectedOperator(PP, LHS, PeekTok);
551  return true;
552  }
553 
554  while (true) {
555  // If this token has a lower precedence than we are allowed to parse, return
556  // it so that higher levels of the recursion can parse it.
557  if (PeekPrec < MinPrec)
558  return false;
559 
560  tok::TokenKind Operator = PeekTok.getKind();
561 
562  // If this is a short-circuiting operator, see if the RHS of the operator is
563  // dead. Note that this cannot just clobber ValueLive. Consider
564  // "0 && 1 ? 4 : 1 / 0", which is parsed as "(0 && 1) ? 4 : (1 / 0)". In
565  // this example, the RHS of the && being dead does not make the rest of the
566  // expr dead.
567  bool RHSIsLive;
568  if (Operator == tok::ampamp && LHS.Val == 0)
569  RHSIsLive = false; // RHS of "0 && x" is dead.
570  else if (Operator == tok::pipepipe && LHS.Val != 0)
571  RHSIsLive = false; // RHS of "1 || x" is dead.
572  else if (Operator == tok::question && LHS.Val == 0)
573  RHSIsLive = false; // RHS (x) of "0 ? x : y" is dead.
574  else
575  RHSIsLive = ValueLive;
576 
577  // Consume the operator, remembering the operator's location for reporting.
578  SourceLocation OpLoc = PeekTok.getLocation();
579  PP.LexNonComment(PeekTok);
580 
581  PPValue RHS(LHS.getBitWidth());
582  // Parse the RHS of the operator.
583  DefinedTracker DT;
584  if (EvaluateValue(RHS, PeekTok, DT, RHSIsLive, PP)) return true;
585  IncludedUndefinedIds = DT.IncludedUndefinedIds;
586 
587  // Remember the precedence of this operator and get the precedence of the
588  // operator immediately to the right of the RHS.
589  unsigned ThisPrec = PeekPrec;
590  PeekPrec = getPrecedence(PeekTok.getKind());
591 
592  // If this token isn't valid, report the error.
593  if (PeekPrec == ~0U) {
594  diagnoseUnexpectedOperator(PP, RHS, PeekTok);
595  return true;
596  }
597 
598  // Decide whether to include the next binop in this subexpression. For
599  // example, when parsing x+y*z and looking at '*', we want to recursively
600  // handle y*z as a single subexpression. We do this because the precedence
601  // of * is higher than that of +. The only strange case we have to handle
602  // here is for the ?: operator, where the precedence is actually lower than
603  // the LHS of the '?'. The grammar rule is:
604  //
605  // conditional-expression ::=
606  // logical-OR-expression ? expression : conditional-expression
607  // where 'expression' is actually comma-expression.
608  unsigned RHSPrec;
609  if (Operator == tok::question)
610  // The RHS of "?" should be maximally consumed as an expression.
611  RHSPrec = getPrecedence(tok::comma);
612  else // All others should munch while higher precedence.
613  RHSPrec = ThisPrec+1;
614 
615  if (PeekPrec >= RHSPrec) {
616  if (EvaluateDirectiveSubExpr(RHS, RHSPrec, PeekTok, RHSIsLive,
617  IncludedUndefinedIds, PP))
618  return true;
619  PeekPrec = getPrecedence(PeekTok.getKind());
620  }
621  assert(PeekPrec <= ThisPrec && "Recursion didn't work!");
622 
623  // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if
624  // either operand is unsigned.
625  llvm::APSInt Res(LHS.getBitWidth());
626  switch (Operator) {
627  case tok::question: // No UAC for x and y in "x ? y : z".
628  case tok::lessless: // Shift amount doesn't UAC with shift value.
629  case tok::greatergreater: // Shift amount doesn't UAC with shift value.
630  case tok::comma: // Comma operands are not subject to UACs.
631  case tok::pipepipe: // Logical || does not do UACs.
632  case tok::ampamp: // Logical && does not do UACs.
633  break; // No UAC
634  default:
635  Res.setIsUnsigned(LHS.isUnsigned()|RHS.isUnsigned());
636  // If this just promoted something from signed to unsigned, and if the
637  // value was negative, warn about it.
638  if (ValueLive && Res.isUnsigned()) {
639  if (!LHS.isUnsigned() && LHS.Val.isNegative())
640  PP.Diag(OpLoc, diag::warn_pp_convert_to_positive) << 0
641  << LHS.Val.toString(10, true) + " to " +
642  LHS.Val.toString(10, false)
643  << LHS.getRange() << RHS.getRange();
644  if (!RHS.isUnsigned() && RHS.Val.isNegative())
645  PP.Diag(OpLoc, diag::warn_pp_convert_to_positive) << 1
646  << RHS.Val.toString(10, true) + " to " +
647  RHS.Val.toString(10, false)
648  << LHS.getRange() << RHS.getRange();
649  }
650  LHS.Val.setIsUnsigned(Res.isUnsigned());
651  RHS.Val.setIsUnsigned(Res.isUnsigned());
652  }
653 
654  bool Overflow = false;
655  switch (Operator) {
656  default: llvm_unreachable("Unknown operator token!");
657  case tok::percent:
658  if (RHS.Val != 0)
659  Res = LHS.Val % RHS.Val;
660  else if (ValueLive) {
661  PP.Diag(OpLoc, diag::err_pp_remainder_by_zero)
662  << LHS.getRange() << RHS.getRange();
663  return true;
664  }
665  break;
666  case tok::slash:
667  if (RHS.Val != 0) {
668  if (LHS.Val.isSigned())
669  Res = llvm::APSInt(LHS.Val.sdiv_ov(RHS.Val, Overflow), false);
670  else
671  Res = LHS.Val / RHS.Val;
672  } else if (ValueLive) {
673  PP.Diag(OpLoc, diag::err_pp_division_by_zero)
674  << LHS.getRange() << RHS.getRange();
675  return true;
676  }
677  break;
678 
679  case tok::star:
680  if (Res.isSigned())
681  Res = llvm::APSInt(LHS.Val.smul_ov(RHS.Val, Overflow), false);
682  else
683  Res = LHS.Val * RHS.Val;
684  break;
685  case tok::lessless: {
686  // Determine whether overflow is about to happen.
687  if (LHS.isUnsigned())
688  Res = LHS.Val.ushl_ov(RHS.Val, Overflow);
689  else
690  Res = llvm::APSInt(LHS.Val.sshl_ov(RHS.Val, Overflow), false);
691  break;
692  }
693  case tok::greatergreater: {
694  // Determine whether overflow is about to happen.
695  unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue());
696  if (ShAmt >= LHS.getBitWidth()) {
697  Overflow = true;
698  ShAmt = LHS.getBitWidth()-1;
699  }
700  Res = LHS.Val >> ShAmt;
701  break;
702  }
703  case tok::plus:
704  if (LHS.isUnsigned())
705  Res = LHS.Val + RHS.Val;
706  else
707  Res = llvm::APSInt(LHS.Val.sadd_ov(RHS.Val, Overflow), false);
708  break;
709  case tok::minus:
710  if (LHS.isUnsigned())
711  Res = LHS.Val - RHS.Val;
712  else
713  Res = llvm::APSInt(LHS.Val.ssub_ov(RHS.Val, Overflow), false);
714  break;
715  case tok::lessequal:
716  Res = LHS.Val <= RHS.Val;
717  Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
718  break;
719  case tok::less:
720  Res = LHS.Val < RHS.Val;
721  Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
722  break;
723  case tok::greaterequal:
724  Res = LHS.Val >= RHS.Val;
725  Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
726  break;
727  case tok::greater:
728  Res = LHS.Val > RHS.Val;
729  Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
730  break;
731  case tok::exclaimequal:
732  Res = LHS.Val != RHS.Val;
733  Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed)
734  break;
735  case tok::equalequal:
736  Res = LHS.Val == RHS.Val;
737  Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed)
738  break;
739  case tok::amp:
740  Res = LHS.Val & RHS.Val;
741  break;
742  case tok::caret:
743  Res = LHS.Val ^ RHS.Val;
744  break;
745  case tok::pipe:
746  Res = LHS.Val | RHS.Val;
747  break;
748  case tok::ampamp:
749  Res = (LHS.Val != 0 && RHS.Val != 0);
750  Res.setIsUnsigned(false); // C99 6.5.13p3, result is always int (signed)
751  break;
752  case tok::pipepipe:
753  Res = (LHS.Val != 0 || RHS.Val != 0);
754  Res.setIsUnsigned(false); // C99 6.5.14p3, result is always int (signed)
755  break;
756  case tok::comma:
757  // Comma is invalid in pp expressions in c89/c++ mode, but is valid in C99
758  // if not being evaluated.
759  if (!PP.getLangOpts().C99 || ValueLive)
760  PP.Diag(OpLoc, diag::ext_pp_comma_expr)
761  << LHS.getRange() << RHS.getRange();
762  Res = RHS.Val; // LHS = LHS,RHS -> RHS.
763  break;
764  case tok::question: {
765  // Parse the : part of the expression.
766  if (PeekTok.isNot(tok::colon)) {
767  PP.Diag(PeekTok.getLocation(), diag::err_expected)
768  << tok::colon << LHS.getRange() << RHS.getRange();
769  PP.Diag(OpLoc, diag::note_matching) << tok::question;
770  return true;
771  }
772  // Consume the :.
773  PP.LexNonComment(PeekTok);
774 
775  // Evaluate the value after the :.
776  bool AfterColonLive = ValueLive && LHS.Val == 0;
777  PPValue AfterColonVal(LHS.getBitWidth());
778  DefinedTracker DT;
779  if (EvaluateValue(AfterColonVal, PeekTok, DT, AfterColonLive, PP))
780  return true;
781 
782  // Parse anything after the : with the same precedence as ?. We allow
783  // things of equal precedence because ?: is right associative.
784  if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec,
785  PeekTok, AfterColonLive,
786  IncludedUndefinedIds, PP))
787  return true;
788 
789  // Now that we have the condition, the LHS and the RHS of the :, evaluate.
790  Res = LHS.Val != 0 ? RHS.Val : AfterColonVal.Val;
791  RHS.setEnd(AfterColonVal.getRange().getEnd());
792 
793  // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if
794  // either operand is unsigned.
795  Res.setIsUnsigned(RHS.isUnsigned() | AfterColonVal.isUnsigned());
796 
797  // Figure out the precedence of the token after the : part.
798  PeekPrec = getPrecedence(PeekTok.getKind());
799  break;
800  }
801  case tok::colon:
802  // Don't allow :'s to float around without being part of ?: exprs.
803  PP.Diag(OpLoc, diag::err_pp_colon_without_question)
804  << LHS.getRange() << RHS.getRange();
805  return true;
806  }
807 
808  // If this operator is live and overflowed, report the issue.
809  if (Overflow && ValueLive)
810  PP.Diag(OpLoc, diag::warn_pp_expr_overflow)
811  << LHS.getRange() << RHS.getRange();
812 
813  // Put the result back into 'LHS' for our next iteration.
814  LHS.Val = Res;
815  LHS.setEnd(RHS.getRange().getEnd());
816  RHS.setIdentifier(nullptr);
817  }
818 }
819 
820 /// EvaluateDirectiveExpression - Evaluate an integer constant expression that
821 /// may occur after a #if or #elif directive. If the expression is equivalent
822 /// to "!defined(X)" return X in IfNDefMacro.
823 Preprocessor::DirectiveEvalResult
824 Preprocessor::EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro) {
825  SaveAndRestore<bool> PPDir(ParsingIfOrElifDirective, true);
826  // Save the current state of 'DisableMacroExpansion' and reset it to false. If
827  // 'DisableMacroExpansion' is true, then we must be in a macro argument list
828  // in which case a directive is undefined behavior. We want macros to be able
829  // to recursively expand in order to get more gcc-list behavior, so we force
830  // DisableMacroExpansion to false and restore it when we're done parsing the
831  // expression.
832  bool DisableMacroExpansionAtStartOfDirective = DisableMacroExpansion;
833  DisableMacroExpansion = false;
834 
835  // Peek ahead one token.
836  Token Tok;
837  LexNonComment(Tok);
838 
839  // C99 6.10.1p3 - All expressions are evaluated as intmax_t or uintmax_t.
840  unsigned BitWidth = getTargetInfo().getIntMaxTWidth();
841 
842  PPValue ResVal(BitWidth);
843  DefinedTracker DT;
844  SourceLocation ExprStartLoc = SourceMgr.getExpansionLoc(Tok.getLocation());
845  if (EvaluateValue(ResVal, Tok, DT, true, *this)) {
846  // Parse error, skip the rest of the macro line.
847  SourceRange ConditionRange = ExprStartLoc;
848  if (Tok.isNot(tok::eod))
849  ConditionRange = DiscardUntilEndOfDirective();
850 
851  // Restore 'DisableMacroExpansion'.
852  DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
853 
854  // We cannot trust the source range from the value because there was a
855  // parse error. Track the range manually -- the end of the directive is the
856  // end of the condition range.
857  return {false,
859  {ExprStartLoc, ConditionRange.getEnd()}};
860  }
861 
862  // If we are at the end of the expression after just parsing a value, there
863  // must be no (unparenthesized) binary operators involved, so we can exit
864  // directly.
865  if (Tok.is(tok::eod)) {
866  // If the expression we parsed was of the form !defined(macro), return the
867  // macro in IfNDefMacro.
869  IfNDefMacro = DT.TheMacro;
870 
871  // Restore 'DisableMacroExpansion'.
872  DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
873  return {ResVal.Val != 0, DT.IncludedUndefinedIds, ResVal.getRange()};
874  }
875 
876  // Otherwise, we must have a binary operator (e.g. "#if 1 < 2"), so parse the
877  // operator and the stuff after it.
878  if (EvaluateDirectiveSubExpr(ResVal, getPrecedence(tok::question),
879  Tok, true, DT.IncludedUndefinedIds, *this)) {
880  // Parse error, skip the rest of the macro line.
881  if (Tok.isNot(tok::eod))
882  DiscardUntilEndOfDirective();
883 
884  // Restore 'DisableMacroExpansion'.
885  DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
886  return {false, DT.IncludedUndefinedIds, ResVal.getRange()};
887  }
888 
889  // If we aren't at the tok::eod token, something bad happened, like an extra
890  // ')' token.
891  if (Tok.isNot(tok::eod)) {
892  Diag(Tok, diag::err_pp_expected_eol);
893  DiscardUntilEndOfDirective();
894  }
895 
896  // Restore 'DisableMacroExpansion'.
897  DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
898  return {ResVal.Val != 0, DT.IncludedUndefinedIds, ResVal.getRange()};
899 }
static DiagnosticBuilder Diag(DiagnosticsEngine *Diags, const LangOptions &Features, FullSourceLoc TokLoc, const char *TokBegin, const char *TokRangeBegin, const char *TokRangeEnd, unsigned DiagID)
Produce a diagnostic highlighting some portion of a literal.
void markMacroAsUsed(MacroInfo *MI)
A macro is used, update information about macros that need unused warnings.
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:94
Defines the SourceManager interface.
static unsigned getPrecedence(tok::TokenKind Kind)
getPrecedence - Return the precedence of the specified binary operator token.
Defines the clang::MacroInfo and clang::MacroDirective classes.
A description of the current definition of a macro.
Definition: MacroInfo.h:564
unsigned getCharWidth() const
Definition: TargetInfo.h:380
void setCodeCompletionReached()
Note that we hit the code-completion point.
void setBegin(SourceLocation b)
This interface provides a way to observe the actions of the preprocessor as it does its thing...
Definition: PPCallbacks.h:35
tok::TokenKind getKind() const
Definition: Token.h:89
One of these records is kept for each identifier that is lexed.
bool isStr(const char(&Str)[StrLen]) const
Return true if this is the identifier for the specified string.
LineState State
bool CheckMacroName(Token &MacroNameTok, MacroUse isDefineUndef, bool *ShadowFlag=nullptr)
unsigned getChar32Width() const
getChar32Width/Align - Return the size of &#39;char32_t&#39; for this target, in bits.
Definition: TargetInfo.h:566
bool isCPlusPlusOperatorKeyword() const
const TargetInfo & getTargetInfo() const
Definition: Preprocessor.h:818
Token - This structure provides full information about a lexed token.
Definition: Token.h:34
const LangOptions & getLangOpts() const
Definition: Preprocessor.h:817
static bool isTypeSigned(IntType T)
Returns true if the type is signed; false otherwise.
Definition: TargetInfo.cpp:302
StringRef getSpelling(SourceLocation loc, SmallVectorImpl< char > &buffer, bool *invalid=nullptr) const
Return the &#39;spelling&#39; of the token at the given location; does not go up to the spelling location or ...
bool hasUDSuffix() const
Return true if this token is a string or character literal which has a ud-suffix. ...
Definition: Token.h:290
const FormatToken & Tok
void LexNonComment(Token &Result)
Lex a token.
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, and whose precedence is PeekPrec.
Exposes information about the current target.
Definition: TargetInfo.h:161
TrackerState
Each time a Value is evaluated, it returns information about whether the parsed value is of the form ...
unsigned getIntWidth() const
getIntWidth/Align - Return the size of &#39;signed int&#39; and &#39;unsigned int&#39; for this target, in bits.
Definition: TargetInfo.h:393
SourceLocation getLocation() const
Return a source location identifier for the specified offset in the current file. ...
Definition: Token.h:123
Defines the clang::Preprocessor interface.
CharLiteralParser - Perform interpretation and semantic analysis of a character literal.
Defines the clang::IdentifierInfo, clang::IdentifierTable, and clang::Selector interfaces.
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...
SourceLocation getEnd() const
PPCallbacks * getPPCallbacks() const
Definition: Preprocessor.h:909
The result type of a method or function.
static StringRef getIdentifier(const Token &Tok)
SourceManager & getSourceManager() const
Definition: Preprocessor.h:821
unsigned getWCharWidth() const
getWCharWidth/Align - Return the size of &#39;wchar_t&#39; for this target, in bits.
Definition: TargetInfo.h:556
IdentifierInfo * TheMacro
TheMacro - When the state is DefinedMacro or NotDefinedMacro, this indicates the macro that was check...
Kind
Encodes a location in the source.
unsigned getChar16Width() const
getChar16Width/Align - Return the size of &#39;char16_t&#39; for this target, in bits.
Definition: TargetInfo.h:561
MacroDefinition getMacroDefinition(const IdentifierInfo *II)
Definition: Preprocessor.h:942
enum DefinedTracker::TrackerState State
IdentifierInfo * getIdentifierInfo() const
Definition: Token.h:176
CodeCompletionHandler * getCodeCompletionHandler() const
Retrieve the current code-completion handler.
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:24
static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT, bool ValueLive, Preprocessor &PP)
EvaluateDefined - Process a &#39;defined(sym)&#39; expression.
virtual void CodeCompletePreprocessorExpression()
Callback invoked when performing code completion in a preprocessor expression, such as the condition ...
bool isNot(tok::TokenKind K) const
Definition: Token.h:95
Dataflow Directional Tag Classes.
bool isValid() const
Return true if this is a valid SourceLocation object.
DefinedTracker - This struct is used while parsing expressions to keep track of whether !defined(X) h...
FileID getFileID(SourceLocation SpellingLoc) const
Return the FileID for a SourceLocation.
void LexUnexpandedNonComment(Token &Result)
Like LexNonComment, but this disables macro expansion of identifier tokens.
Defines the PPCallbacks interface.
Defines the clang::TokenKind enum and support functions.
const SrcMgr::SLocEntry & getSLocEntry(FileID FID, bool *Invalid=nullptr) const
virtual void CodeCompleteMacroName(bool IsDefinition)
Callback invoked when performing code completion in a context where the name of a macro is expected...
Defines the clang::SourceLocation class and associated facilities.
void setEnd(SourceLocation e)
IntType getWCharType() const
Definition: TargetInfo.h:297
Defines the clang::TargetInfo interface.
NumericLiteralParser - This performs strict semantic analysis of the content of a ppnumber...
MacroInfo * getMacroInfo() const
Get the MacroInfo that should be used for this definition.
Definition: MacroInfo.h:580
A trivial tuple used to represent a source range.
DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID) const
Forwarding function for diagnostics.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:124