clang  3.7.0
PPExpressions.cpp
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1 //===--- PPExpressions.cpp - Preprocessor Expression Evaluation -----------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements the Preprocessor::EvaluateDirectiveExpression method,
11 // which parses and evaluates integer constant expressions for #if directives.
12 //
13 //===----------------------------------------------------------------------===//
14 //
15 // FIXME: implement testing for #assert's.
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang/Basic/TargetInfo.h"
24 #include "clang/Lex/MacroInfo.h"
25 #include "llvm/ADT/APSInt.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/SaveAndRestore.h"
28 using namespace clang;
29 
30 namespace {
31 
32 /// PPValue - Represents the value of a subexpression of a preprocessor
33 /// conditional and the source range covered by it.
34 class PPValue {
35  SourceRange Range;
36 public:
37  llvm::APSInt Val;
38 
39  // Default ctor - Construct an 'invalid' PPValue.
40  PPValue(unsigned BitWidth) : Val(BitWidth) {}
41 
42  unsigned getBitWidth() const { return Val.getBitWidth(); }
43  bool isUnsigned() const { return Val.isUnsigned(); }
44 
45  const SourceRange &getRange() const { return Range; }
46 
47  void setRange(SourceLocation L) { Range.setBegin(L); Range.setEnd(L); }
48  void setRange(SourceLocation B, SourceLocation E) {
49  Range.setBegin(B); Range.setEnd(E);
50  }
51  void setBegin(SourceLocation L) { Range.setBegin(L); }
52  void setEnd(SourceLocation L) { Range.setEnd(L); }
53 };
54 
55 }
56 
57 static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
58  Token &PeekTok, bool ValueLive,
59  Preprocessor &PP);
60 
61 /// DefinedTracker - This struct is used while parsing expressions to keep track
62 /// of whether !defined(X) has been seen.
63 ///
64 /// With this simple scheme, we handle the basic forms:
65 /// !defined(X) and !defined X
66 /// but we also trivially handle (silly) stuff like:
67 /// !!!defined(X) and +!defined(X) and !+!+!defined(X) and !(defined(X)).
69  /// Each time a Value is evaluated, it returns information about whether the
70  /// parsed value is of the form defined(X), !defined(X) or is something else.
71  enum TrackerState {
72  DefinedMacro, // defined(X)
73  NotDefinedMacro, // !defined(X)
74  Unknown // Something else.
75  } State;
76  /// TheMacro - When the state is DefinedMacro or NotDefinedMacro, this
77  /// indicates the macro that was checked.
79 };
80 
81 /// EvaluateDefined - Process a 'defined(sym)' expression.
82 static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
83  bool ValueLive, Preprocessor &PP) {
84  SourceLocation beginLoc(PeekTok.getLocation());
85  Result.setBegin(beginLoc);
86 
87  // Get the next token, don't expand it.
88  PP.LexUnexpandedNonComment(PeekTok);
89 
90  // Two options, it can either be a pp-identifier or a (.
91  SourceLocation LParenLoc;
92  if (PeekTok.is(tok::l_paren)) {
93  // Found a paren, remember we saw it and skip it.
94  LParenLoc = PeekTok.getLocation();
95  PP.LexUnexpandedNonComment(PeekTok);
96  }
97 
98  if (PeekTok.is(tok::code_completion)) {
99  if (PP.getCodeCompletionHandler())
102  PP.LexUnexpandedNonComment(PeekTok);
103  }
104 
105  // If we don't have a pp-identifier now, this is an error.
106  if (PP.CheckMacroName(PeekTok, MU_Other))
107  return true;
108 
109  // Otherwise, we got an identifier, is it defined to something?
110  IdentifierInfo *II = PeekTok.getIdentifierInfo();
111  MacroDefinition Macro = PP.getMacroDefinition(II);
112  Result.Val = !!Macro;
113  Result.Val.setIsUnsigned(false); // Result is signed intmax_t.
114 
115  // If there is a macro, mark it used.
116  if (Result.Val != 0 && ValueLive)
117  PP.markMacroAsUsed(Macro.getMacroInfo());
118 
119  // Save macro token for callback.
120  Token macroToken(PeekTok);
121 
122  // If we are in parens, ensure we have a trailing ).
123  if (LParenLoc.isValid()) {
124  // Consume identifier.
125  Result.setEnd(PeekTok.getLocation());
126  PP.LexUnexpandedNonComment(PeekTok);
127 
128  if (PeekTok.isNot(tok::r_paren)) {
129  PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_after)
130  << "'defined'" << tok::r_paren;
131  PP.Diag(LParenLoc, diag::note_matching) << tok::l_paren;
132  return true;
133  }
134  // Consume the ).
135  Result.setEnd(PeekTok.getLocation());
136  PP.LexNonComment(PeekTok);
137  } else {
138  // Consume identifier.
139  Result.setEnd(PeekTok.getLocation());
140  PP.LexNonComment(PeekTok);
141  }
142 
143  // Invoke the 'defined' callback.
144  if (PPCallbacks *Callbacks = PP.getPPCallbacks()) {
145  Callbacks->Defined(macroToken, Macro,
146  SourceRange(beginLoc, PeekTok.getLocation()));
147  }
148 
149  // Success, remember that we saw defined(X).
151  DT.TheMacro = II;
152  return false;
153 }
154 
155 /// EvaluateValue - Evaluate the token PeekTok (and any others needed) and
156 /// return the computed value in Result. Return true if there was an error
157 /// parsing. This function also returns information about the form of the
158 /// expression in DT. See above for information on what DT means.
159 ///
160 /// If ValueLive is false, then this value is being evaluated in a context where
161 /// the result is not used. As such, avoid diagnostics that relate to
162 /// evaluation.
163 static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
164  bool ValueLive, Preprocessor &PP) {
166 
167  if (PeekTok.is(tok::code_completion)) {
168  if (PP.getCodeCompletionHandler())
171  PP.LexNonComment(PeekTok);
172  }
173 
174  // If this token's spelling is a pp-identifier, check to see if it is
175  // 'defined' or if it is a macro. Note that we check here because many
176  // keywords are pp-identifiers, so we can't check the kind.
177  if (IdentifierInfo *II = PeekTok.getIdentifierInfo()) {
178  // Handle "defined X" and "defined(X)".
179  if (II->isStr("defined"))
180  return(EvaluateDefined(Result, PeekTok, DT, ValueLive, PP));
181 
182  // If this identifier isn't 'defined' or one of the special
183  // preprocessor keywords and it wasn't macro expanded, it turns
184  // into a simple 0, unless it is the C++ keyword "true", in which case it
185  // turns into "1".
186  if (ValueLive &&
187  II->getTokenID() != tok::kw_true &&
188  II->getTokenID() != tok::kw_false)
189  PP.Diag(PeekTok, diag::warn_pp_undef_identifier) << II;
190  Result.Val = II->getTokenID() == tok::kw_true;
191  Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0.
192  Result.setRange(PeekTok.getLocation());
193  PP.LexNonComment(PeekTok);
194  return false;
195  }
196 
197  switch (PeekTok.getKind()) {
198  default: // Non-value token.
199  PP.Diag(PeekTok, diag::err_pp_expr_bad_token_start_expr);
200  return true;
201  case tok::eod:
202  case tok::r_paren:
203  // If there is no expression, report and exit.
204  PP.Diag(PeekTok, diag::err_pp_expected_value_in_expr);
205  return true;
206  case tok::numeric_constant: {
207  SmallString<64> IntegerBuffer;
208  bool NumberInvalid = false;
209  StringRef Spelling = PP.getSpelling(PeekTok, IntegerBuffer,
210  &NumberInvalid);
211  if (NumberInvalid)
212  return true; // a diagnostic was already reported
213 
214  NumericLiteralParser Literal(Spelling, PeekTok.getLocation(), PP);
215  if (Literal.hadError)
216  return true; // a diagnostic was already reported.
217 
218  if (Literal.isFloatingLiteral() || Literal.isImaginary) {
219  PP.Diag(PeekTok, diag::err_pp_illegal_floating_literal);
220  return true;
221  }
222  assert(Literal.isIntegerLiteral() && "Unknown ppnumber");
223 
224  // Complain about, and drop, any ud-suffix.
225  if (Literal.hasUDSuffix())
226  PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*integer*/1;
227 
228  // 'long long' is a C99 or C++11 feature.
229  if (!PP.getLangOpts().C99 && Literal.isLongLong) {
230  if (PP.getLangOpts().CPlusPlus)
231  PP.Diag(PeekTok,
232  PP.getLangOpts().CPlusPlus11 ?
233  diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong);
234  else
235  PP.Diag(PeekTok, diag::ext_c99_longlong);
236  }
237 
238  // Parse the integer literal into Result.
239  if (Literal.GetIntegerValue(Result.Val)) {
240  // Overflow parsing integer literal.
241  if (ValueLive)
242  PP.Diag(PeekTok, diag::err_integer_literal_too_large)
243  << /* Unsigned */ 1;
244  Result.Val.setIsUnsigned(true);
245  } else {
246  // Set the signedness of the result to match whether there was a U suffix
247  // or not.
248  Result.Val.setIsUnsigned(Literal.isUnsigned);
249 
250  // Detect overflow based on whether the value is signed. If signed
251  // and if the value is too large, emit a warning "integer constant is so
252  // large that it is unsigned" e.g. on 12345678901234567890 where intmax_t
253  // is 64-bits.
254  if (!Literal.isUnsigned && Result.Val.isNegative()) {
255  // Octal, hexadecimal, and binary literals are implicitly unsigned if
256  // the value does not fit into a signed integer type.
257  if (ValueLive && Literal.getRadix() == 10)
258  PP.Diag(PeekTok, diag::ext_integer_literal_too_large_for_signed);
259  Result.Val.setIsUnsigned(true);
260  }
261  }
262 
263  // Consume the token.
264  Result.setRange(PeekTok.getLocation());
265  PP.LexNonComment(PeekTok);
266  return false;
267  }
268  case tok::char_constant: // 'x'
269  case tok::wide_char_constant: // L'x'
270  case tok::utf8_char_constant: // u8'x'
271  case tok::utf16_char_constant: // u'x'
272  case tok::utf32_char_constant: { // U'x'
273  // Complain about, and drop, any ud-suffix.
274  if (PeekTok.hasUDSuffix())
275  PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*character*/0;
276 
277  SmallString<32> CharBuffer;
278  bool CharInvalid = false;
279  StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid);
280  if (CharInvalid)
281  return true;
282 
283  CharLiteralParser Literal(ThisTok.begin(), ThisTok.end(),
284  PeekTok.getLocation(), PP, PeekTok.getKind());
285  if (Literal.hadError())
286  return true; // A diagnostic was already emitted.
287 
288  // Character literals are always int or wchar_t, expand to intmax_t.
289  const TargetInfo &TI = PP.getTargetInfo();
290  unsigned NumBits;
291  if (Literal.isMultiChar())
292  NumBits = TI.getIntWidth();
293  else if (Literal.isWide())
294  NumBits = TI.getWCharWidth();
295  else if (Literal.isUTF16())
296  NumBits = TI.getChar16Width();
297  else if (Literal.isUTF32())
298  NumBits = TI.getChar32Width();
299  else
300  NumBits = TI.getCharWidth();
301 
302  // Set the width.
303  llvm::APSInt Val(NumBits);
304  // Set the value.
305  Val = Literal.getValue();
306  // Set the signedness. UTF-16 and UTF-32 are always unsigned
307  if (Literal.isWide())
308  Val.setIsUnsigned(!TargetInfo::isTypeSigned(TI.getWCharType()));
309  else if (!Literal.isUTF16() && !Literal.isUTF32())
310  Val.setIsUnsigned(!PP.getLangOpts().CharIsSigned);
311 
312  if (Result.Val.getBitWidth() > Val.getBitWidth()) {
313  Result.Val = Val.extend(Result.Val.getBitWidth());
314  } else {
315  assert(Result.Val.getBitWidth() == Val.getBitWidth() &&
316  "intmax_t smaller than char/wchar_t?");
317  Result.Val = Val;
318  }
319 
320  // Consume the token.
321  Result.setRange(PeekTok.getLocation());
322  PP.LexNonComment(PeekTok);
323  return false;
324  }
325  case tok::l_paren: {
326  SourceLocation Start = PeekTok.getLocation();
327  PP.LexNonComment(PeekTok); // Eat the (.
328  // Parse the value and if there are any binary operators involved, parse
329  // them.
330  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
331 
332  // If this is a silly value like (X), which doesn't need parens, check for
333  // !(defined X).
334  if (PeekTok.is(tok::r_paren)) {
335  // Just use DT unmodified as our result.
336  } else {
337  // Otherwise, we have something like (x+y), and we consumed '(x'.
338  if (EvaluateDirectiveSubExpr(Result, 1, PeekTok, ValueLive, PP))
339  return true;
340 
341  if (PeekTok.isNot(tok::r_paren)) {
342  PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_rparen)
343  << Result.getRange();
344  PP.Diag(Start, diag::note_matching) << tok::l_paren;
345  return true;
346  }
348  }
349  Result.setRange(Start, PeekTok.getLocation());
350  PP.LexNonComment(PeekTok); // Eat the ).
351  return false;
352  }
353  case tok::plus: {
354  SourceLocation Start = PeekTok.getLocation();
355  // Unary plus doesn't modify the value.
356  PP.LexNonComment(PeekTok);
357  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
358  Result.setBegin(Start);
359  return false;
360  }
361  case tok::minus: {
362  SourceLocation Loc = PeekTok.getLocation();
363  PP.LexNonComment(PeekTok);
364  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
365  Result.setBegin(Loc);
366 
367  // C99 6.5.3.3p3: The sign of the result matches the sign of the operand.
368  Result.Val = -Result.Val;
369 
370  // -MININT is the only thing that overflows. Unsigned never overflows.
371  bool Overflow = !Result.isUnsigned() && Result.Val.isMinSignedValue();
372 
373  // If this operator is live and overflowed, report the issue.
374  if (Overflow && ValueLive)
375  PP.Diag(Loc, diag::warn_pp_expr_overflow) << Result.getRange();
376 
378  return false;
379  }
380 
381  case tok::tilde: {
382  SourceLocation Start = PeekTok.getLocation();
383  PP.LexNonComment(PeekTok);
384  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
385  Result.setBegin(Start);
386 
387  // C99 6.5.3.3p4: The sign of the result matches the sign of the operand.
388  Result.Val = ~Result.Val;
390  return false;
391  }
392 
393  case tok::exclaim: {
394  SourceLocation Start = PeekTok.getLocation();
395  PP.LexNonComment(PeekTok);
396  if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
397  Result.setBegin(Start);
398  Result.Val = !Result.Val;
399  // C99 6.5.3.3p5: The sign of the result is 'int', aka it is signed.
400  Result.Val.setIsUnsigned(false);
401 
404  else if (DT.State == DefinedTracker::NotDefinedMacro)
406  return false;
407  }
408 
409  // FIXME: Handle #assert
410  }
411 }
412 
413 
414 
415 /// getPrecedence - Return the precedence of the specified binary operator
416 /// token. This returns:
417 /// ~0 - Invalid token.
418 /// 14 -> 3 - various operators.
419 /// 0 - 'eod' or ')'
421  switch (Kind) {
422  default: return ~0U;
423  case tok::percent:
424  case tok::slash:
425  case tok::star: return 14;
426  case tok::plus:
427  case tok::minus: return 13;
428  case tok::lessless:
429  case tok::greatergreater: return 12;
430  case tok::lessequal:
431  case tok::less:
432  case tok::greaterequal:
433  case tok::greater: return 11;
434  case tok::exclaimequal:
435  case tok::equalequal: return 10;
436  case tok::amp: return 9;
437  case tok::caret: return 8;
438  case tok::pipe: return 7;
439  case tok::ampamp: return 6;
440  case tok::pipepipe: return 5;
441  case tok::question: return 4;
442  case tok::comma: return 3;
443  case tok::colon: return 2;
444  case tok::r_paren: return 0;// Lowest priority, end of expr.
445  case tok::eod: return 0;// Lowest priority, end of directive.
446  }
447 }
448 
449 
450 /// EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is
451 /// PeekTok, and whose precedence is PeekPrec. This returns the result in LHS.
452 ///
453 /// If ValueLive is false, then this value is being evaluated in a context where
454 /// the result is not used. As such, avoid diagnostics that relate to
455 /// evaluation, such as division by zero warnings.
456 static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
457  Token &PeekTok, bool ValueLive,
458  Preprocessor &PP) {
459  unsigned PeekPrec = getPrecedence(PeekTok.getKind());
460  // If this token isn't valid, report the error.
461  if (PeekPrec == ~0U) {
462  PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop)
463  << LHS.getRange();
464  return true;
465  }
466 
467  while (1) {
468  // If this token has a lower precedence than we are allowed to parse, return
469  // it so that higher levels of the recursion can parse it.
470  if (PeekPrec < MinPrec)
471  return false;
472 
473  tok::TokenKind Operator = PeekTok.getKind();
474 
475  // If this is a short-circuiting operator, see if the RHS of the operator is
476  // dead. Note that this cannot just clobber ValueLive. Consider
477  // "0 && 1 ? 4 : 1 / 0", which is parsed as "(0 && 1) ? 4 : (1 / 0)". In
478  // this example, the RHS of the && being dead does not make the rest of the
479  // expr dead.
480  bool RHSIsLive;
481  if (Operator == tok::ampamp && LHS.Val == 0)
482  RHSIsLive = false; // RHS of "0 && x" is dead.
483  else if (Operator == tok::pipepipe && LHS.Val != 0)
484  RHSIsLive = false; // RHS of "1 || x" is dead.
485  else if (Operator == tok::question && LHS.Val == 0)
486  RHSIsLive = false; // RHS (x) of "0 ? x : y" is dead.
487  else
488  RHSIsLive = ValueLive;
489 
490  // Consume the operator, remembering the operator's location for reporting.
491  SourceLocation OpLoc = PeekTok.getLocation();
492  PP.LexNonComment(PeekTok);
493 
494  PPValue RHS(LHS.getBitWidth());
495  // Parse the RHS of the operator.
496  DefinedTracker DT;
497  if (EvaluateValue(RHS, PeekTok, DT, RHSIsLive, PP)) return true;
498 
499  // Remember the precedence of this operator and get the precedence of the
500  // operator immediately to the right of the RHS.
501  unsigned ThisPrec = PeekPrec;
502  PeekPrec = getPrecedence(PeekTok.getKind());
503 
504  // If this token isn't valid, report the error.
505  if (PeekPrec == ~0U) {
506  PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop)
507  << RHS.getRange();
508  return true;
509  }
510 
511  // Decide whether to include the next binop in this subexpression. For
512  // example, when parsing x+y*z and looking at '*', we want to recursively
513  // handle y*z as a single subexpression. We do this because the precedence
514  // of * is higher than that of +. The only strange case we have to handle
515  // here is for the ?: operator, where the precedence is actually lower than
516  // the LHS of the '?'. The grammar rule is:
517  //
518  // conditional-expression ::=
519  // logical-OR-expression ? expression : conditional-expression
520  // where 'expression' is actually comma-expression.
521  unsigned RHSPrec;
522  if (Operator == tok::question)
523  // The RHS of "?" should be maximally consumed as an expression.
524  RHSPrec = getPrecedence(tok::comma);
525  else // All others should munch while higher precedence.
526  RHSPrec = ThisPrec+1;
527 
528  if (PeekPrec >= RHSPrec) {
529  if (EvaluateDirectiveSubExpr(RHS, RHSPrec, PeekTok, RHSIsLive, PP))
530  return true;
531  PeekPrec = getPrecedence(PeekTok.getKind());
532  }
533  assert(PeekPrec <= ThisPrec && "Recursion didn't work!");
534 
535  // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if
536  // either operand is unsigned.
537  llvm::APSInt Res(LHS.getBitWidth());
538  switch (Operator) {
539  case tok::question: // No UAC for x and y in "x ? y : z".
540  case tok::lessless: // Shift amount doesn't UAC with shift value.
541  case tok::greatergreater: // Shift amount doesn't UAC with shift value.
542  case tok::comma: // Comma operands are not subject to UACs.
543  case tok::pipepipe: // Logical || does not do UACs.
544  case tok::ampamp: // Logical && does not do UACs.
545  break; // No UAC
546  default:
547  Res.setIsUnsigned(LHS.isUnsigned()|RHS.isUnsigned());
548  // If this just promoted something from signed to unsigned, and if the
549  // value was negative, warn about it.
550  if (ValueLive && Res.isUnsigned()) {
551  if (!LHS.isUnsigned() && LHS.Val.isNegative())
552  PP.Diag(OpLoc, diag::warn_pp_convert_lhs_to_positive)
553  << LHS.Val.toString(10, true) + " to " +
554  LHS.Val.toString(10, false)
555  << LHS.getRange() << RHS.getRange();
556  if (!RHS.isUnsigned() && RHS.Val.isNegative())
557  PP.Diag(OpLoc, diag::warn_pp_convert_rhs_to_positive)
558  << RHS.Val.toString(10, true) + " to " +
559  RHS.Val.toString(10, false)
560  << LHS.getRange() << RHS.getRange();
561  }
562  LHS.Val.setIsUnsigned(Res.isUnsigned());
563  RHS.Val.setIsUnsigned(Res.isUnsigned());
564  }
565 
566  bool Overflow = false;
567  switch (Operator) {
568  default: llvm_unreachable("Unknown operator token!");
569  case tok::percent:
570  if (RHS.Val != 0)
571  Res = LHS.Val % RHS.Val;
572  else if (ValueLive) {
573  PP.Diag(OpLoc, diag::err_pp_remainder_by_zero)
574  << LHS.getRange() << RHS.getRange();
575  return true;
576  }
577  break;
578  case tok::slash:
579  if (RHS.Val != 0) {
580  if (LHS.Val.isSigned())
581  Res = llvm::APSInt(LHS.Val.sdiv_ov(RHS.Val, Overflow), false);
582  else
583  Res = LHS.Val / RHS.Val;
584  } else if (ValueLive) {
585  PP.Diag(OpLoc, diag::err_pp_division_by_zero)
586  << LHS.getRange() << RHS.getRange();
587  return true;
588  }
589  break;
590 
591  case tok::star:
592  if (Res.isSigned())
593  Res = llvm::APSInt(LHS.Val.smul_ov(RHS.Val, Overflow), false);
594  else
595  Res = LHS.Val * RHS.Val;
596  break;
597  case tok::lessless: {
598  // Determine whether overflow is about to happen.
599  if (LHS.isUnsigned())
600  Res = LHS.Val.ushl_ov(RHS.Val, Overflow);
601  else
602  Res = llvm::APSInt(LHS.Val.sshl_ov(RHS.Val, Overflow), false);
603  break;
604  }
605  case tok::greatergreater: {
606  // Determine whether overflow is about to happen.
607  unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue());
608  if (ShAmt >= LHS.getBitWidth())
609  Overflow = true, ShAmt = LHS.getBitWidth()-1;
610  Res = LHS.Val >> ShAmt;
611  break;
612  }
613  case tok::plus:
614  if (LHS.isUnsigned())
615  Res = LHS.Val + RHS.Val;
616  else
617  Res = llvm::APSInt(LHS.Val.sadd_ov(RHS.Val, Overflow), false);
618  break;
619  case tok::minus:
620  if (LHS.isUnsigned())
621  Res = LHS.Val - RHS.Val;
622  else
623  Res = llvm::APSInt(LHS.Val.ssub_ov(RHS.Val, Overflow), false);
624  break;
625  case tok::lessequal:
626  Res = LHS.Val <= RHS.Val;
627  Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
628  break;
629  case tok::less:
630  Res = LHS.Val < RHS.Val;
631  Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
632  break;
633  case tok::greaterequal:
634  Res = LHS.Val >= RHS.Val;
635  Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
636  break;
637  case tok::greater:
638  Res = LHS.Val > RHS.Val;
639  Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
640  break;
641  case tok::exclaimequal:
642  Res = LHS.Val != RHS.Val;
643  Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed)
644  break;
645  case tok::equalequal:
646  Res = LHS.Val == RHS.Val;
647  Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed)
648  break;
649  case tok::amp:
650  Res = LHS.Val & RHS.Val;
651  break;
652  case tok::caret:
653  Res = LHS.Val ^ RHS.Val;
654  break;
655  case tok::pipe:
656  Res = LHS.Val | RHS.Val;
657  break;
658  case tok::ampamp:
659  Res = (LHS.Val != 0 && RHS.Val != 0);
660  Res.setIsUnsigned(false); // C99 6.5.13p3, result is always int (signed)
661  break;
662  case tok::pipepipe:
663  Res = (LHS.Val != 0 || RHS.Val != 0);
664  Res.setIsUnsigned(false); // C99 6.5.14p3, result is always int (signed)
665  break;
666  case tok::comma:
667  // Comma is invalid in pp expressions in c89/c++ mode, but is valid in C99
668  // if not being evaluated.
669  if (!PP.getLangOpts().C99 || ValueLive)
670  PP.Diag(OpLoc, diag::ext_pp_comma_expr)
671  << LHS.getRange() << RHS.getRange();
672  Res = RHS.Val; // LHS = LHS,RHS -> RHS.
673  break;
674  case tok::question: {
675  // Parse the : part of the expression.
676  if (PeekTok.isNot(tok::colon)) {
677  PP.Diag(PeekTok.getLocation(), diag::err_expected)
678  << tok::colon << LHS.getRange() << RHS.getRange();
679  PP.Diag(OpLoc, diag::note_matching) << tok::question;
680  return true;
681  }
682  // Consume the :.
683  PP.LexNonComment(PeekTok);
684 
685  // Evaluate the value after the :.
686  bool AfterColonLive = ValueLive && LHS.Val == 0;
687  PPValue AfterColonVal(LHS.getBitWidth());
688  DefinedTracker DT;
689  if (EvaluateValue(AfterColonVal, PeekTok, DT, AfterColonLive, PP))
690  return true;
691 
692  // Parse anything after the : with the same precedence as ?. We allow
693  // things of equal precedence because ?: is right associative.
694  if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec,
695  PeekTok, AfterColonLive, PP))
696  return true;
697 
698  // Now that we have the condition, the LHS and the RHS of the :, evaluate.
699  Res = LHS.Val != 0 ? RHS.Val : AfterColonVal.Val;
700  RHS.setEnd(AfterColonVal.getRange().getEnd());
701 
702  // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if
703  // either operand is unsigned.
704  Res.setIsUnsigned(RHS.isUnsigned() | AfterColonVal.isUnsigned());
705 
706  // Figure out the precedence of the token after the : part.
707  PeekPrec = getPrecedence(PeekTok.getKind());
708  break;
709  }
710  case tok::colon:
711  // Don't allow :'s to float around without being part of ?: exprs.
712  PP.Diag(OpLoc, diag::err_pp_colon_without_question)
713  << LHS.getRange() << RHS.getRange();
714  return true;
715  }
716 
717  // If this operator is live and overflowed, report the issue.
718  if (Overflow && ValueLive)
719  PP.Diag(OpLoc, diag::warn_pp_expr_overflow)
720  << LHS.getRange() << RHS.getRange();
721 
722  // Put the result back into 'LHS' for our next iteration.
723  LHS.Val = Res;
724  LHS.setEnd(RHS.getRange().getEnd());
725  }
726 }
727 
728 /// EvaluateDirectiveExpression - Evaluate an integer constant expression that
729 /// may occur after a #if or #elif directive. If the expression is equivalent
730 /// to "!defined(X)" return X in IfNDefMacro.
731 bool Preprocessor::EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro) {
732  SaveAndRestore<bool> PPDir(ParsingIfOrElifDirective, true);
733  // Save the current state of 'DisableMacroExpansion' and reset it to false. If
734  // 'DisableMacroExpansion' is true, then we must be in a macro argument list
735  // in which case a directive is undefined behavior. We want macros to be able
736  // to recursively expand in order to get more gcc-list behavior, so we force
737  // DisableMacroExpansion to false and restore it when we're done parsing the
738  // expression.
739  bool DisableMacroExpansionAtStartOfDirective = DisableMacroExpansion;
740  DisableMacroExpansion = false;
741 
742  // Peek ahead one token.
743  Token Tok;
744  LexNonComment(Tok);
745 
746  // C99 6.10.1p3 - All expressions are evaluated as intmax_t or uintmax_t.
747  unsigned BitWidth = getTargetInfo().getIntMaxTWidth();
748 
749  PPValue ResVal(BitWidth);
750  DefinedTracker DT;
751  if (EvaluateValue(ResVal, Tok, DT, true, *this)) {
752  // Parse error, skip the rest of the macro line.
753  if (Tok.isNot(tok::eod))
755 
756  // Restore 'DisableMacroExpansion'.
757  DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
758  return false;
759  }
760 
761  // If we are at the end of the expression after just parsing a value, there
762  // must be no (unparenthesized) binary operators involved, so we can exit
763  // directly.
764  if (Tok.is(tok::eod)) {
765  // If the expression we parsed was of the form !defined(macro), return the
766  // macro in IfNDefMacro.
768  IfNDefMacro = DT.TheMacro;
769 
770  // Restore 'DisableMacroExpansion'.
771  DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
772  return ResVal.Val != 0;
773  }
774 
775  // Otherwise, we must have a binary operator (e.g. "#if 1 < 2"), so parse the
776  // operator and the stuff after it.
777  if (EvaluateDirectiveSubExpr(ResVal, getPrecedence(tok::question),
778  Tok, true, *this)) {
779  // Parse error, skip the rest of the macro line.
780  if (Tok.isNot(tok::eod))
782 
783  // Restore 'DisableMacroExpansion'.
784  DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
785  return false;
786  }
787 
788  // If we aren't at the tok::eod token, something bad happened, like an extra
789  // ')' token.
790  if (Tok.isNot(tok::eod)) {
791  Diag(Tok, diag::err_pp_expected_eol);
793  }
794 
795  // Restore 'DisableMacroExpansion'.
796  DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
797  return ResVal.Val != 0;
798 }
void markMacroAsUsed(MacroInfo *MI)
A macro is used, update information about macros that need unused warnings.
static unsigned getPrecedence(tok::TokenKind Kind)
Defines the clang::MacroInfo and clang::MacroDirective classes.
A description of the current definition of a macro.
Definition: MacroInfo.h:564
void setCodeCompletionReached()
Note that we hit the code-completion point.
CodeCompletionHandler * getCodeCompletionHandler() const
Retrieve the current code-completion handler.
Definition: Preprocessor.h:962
void setBegin(SourceLocation b)
This interface provides a way to observe the actions of the preprocessor as it does its thing...
Definition: PPCallbacks.h:38
StringRef getSpelling(SourceLocation loc, SmallVectorImpl< char > &buffer, bool *invalid=nullptr) const
LineState State
bool CheckMacroName(Token &MacroNameTok, MacroUse isDefineUndef, bool *ShadowFlag=nullptr)
const LangOptions & getLangOpts() const
Definition: Preprocessor.h:679
MacroInfo * getMacroInfo() const
Get the MacroInfo that should be used for this definition.
Definition: MacroInfo.h:580
static bool isTypeSigned(IntType T)
Returns true if the type is signed; false otherwise.
void LexNonComment(Token &Result)
Lex a token. If it's a comment, keep lexing until we get something not a comment. ...
tok::TokenKind getKind() const
Definition: Token.h:90
const TargetInfo & getTargetInfo() const
Definition: Preprocessor.h:680
DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID) const
Exposes information about the current target.
Defines the clang::Preprocessor interface.
bool hasUDSuffix() const
Return true if this token is a string or character literal which has a ud-suffix. ...
Definition: Token.h:290
unsigned getIntMaxTWidth() const
Return the size of intmax_t and uintmax_t for this target, in bits.
SourceLocation getLocation() const
Return a source location identifier for the specified offset in the current file. ...
Definition: Token.h:124
static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT, bool ValueLive, Preprocessor &PP)
bool isNot(tok::TokenKind K) const
Definition: Token.h:96
IdentifierInfo * TheMacro
Kind
Encodes a location in the source. The SourceManager can decode this to get at the full include stack...
bool isValid() const
Return true if this is a valid SourceLocation object.
MacroDefinition getMacroDefinition(const IdentifierInfo *II)
Definition: Preprocessor.h:805
enum DefinedTracker::TrackerState State
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:25
PPCallbacks * getPPCallbacks() const
Accessors for preprocessor callbacks.
Definition: Preprocessor.h:772
bool is(tok::TokenKind K) const
Definition: Token.h:95
static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT, bool ValueLive, Preprocessor &PP)
EvaluateDefined - Process a 'defined(sym)' expression.
virtual void CodeCompletePreprocessorExpression()
Callback invoked when performing code completion in a preprocessor expression, such as the condition ...
void LexUnexpandedNonComment(Token &Result)
Like LexNonComment, but this disables macro expansion of identifier tokens.
virtual void CodeCompleteMacroName(bool IsDefinition)
Callback invoked when performing code completion in a context where the name of a macro is expected...
static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, Token &PeekTok, bool ValueLive, Preprocessor &PP)
Defines the clang::TargetInfo interface.
void DiscardUntilEndOfDirective()
Read and discard all tokens remaining on the current line until the tok::eod token is found...
A trivial tuple used to represent a source range.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:96
IdentifierInfo * getIdentifierInfo() const
Definition: Token.h:177