1 //===--- PPExpressions.cpp - Preprocessor Expression Evaluation -----------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the Preprocessor::EvaluateDirectiveExpression method,
11 // which parses and evaluates integer constant expressions for #if directives.
13 //===----------------------------------------------------------------------===//
15 // FIXME: implement testing for #assert's.
17 //===----------------------------------------------------------------------===//
19 #include "clang/Lex/Preprocessor.h"
20 #include "clang/Lex/MacroInfo.h"
21 #include "clang/Lex/LiteralSupport.h"
22 #include "clang/Lex/CodeCompletionHandler.h"
23 #include "clang/Basic/TargetInfo.h"
24 #include "clang/Lex/LexDiagnostic.h"
25 #include "llvm/ADT/APSInt.h"
26 #include "llvm/Support/ErrorHandling.h"
27 using namespace clang;
31 /// PPValue - Represents the value of a subexpression of a preprocessor
32 /// conditional and the source range covered by it.
38 // Default ctor - Construct an 'invalid' PPValue.
39 PPValue(unsigned BitWidth) : Val(BitWidth) {}
41 unsigned getBitWidth() const { return Val.getBitWidth(); }
42 bool isUnsigned() const { return Val.isUnsigned(); }
44 const SourceRange &getRange() const { return Range; }
46 void setRange(SourceLocation L) { Range.setBegin(L); Range.setEnd(L); }
47 void setRange(SourceLocation B, SourceLocation E) {
48 Range.setBegin(B); Range.setEnd(E);
50 void setBegin(SourceLocation L) { Range.setBegin(L); }
51 void setEnd(SourceLocation L) { Range.setEnd(L); }
56 static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
57 Token &PeekTok, bool ValueLive,
60 /// DefinedTracker - This struct is used while parsing expressions to keep track
61 /// of whether !defined(X) has been seen.
63 /// With this simple scheme, we handle the basic forms:
64 /// !defined(X) and !defined X
65 /// but we also trivially handle (silly) stuff like:
66 /// !!!defined(X) and +!defined(X) and !+!+!defined(X) and !(defined(X)).
67 struct DefinedTracker {
68 /// Each time a Value is evaluated, it returns information about whether the
69 /// parsed value is of the form defined(X), !defined(X) or is something else.
71 DefinedMacro, // defined(X)
72 NotDefinedMacro, // !defined(X)
73 Unknown // Something else.
75 /// TheMacro - When the state is DefinedMacro or NotDefinedMacro, this
76 /// indicates the macro that was checked.
77 IdentifierInfo *TheMacro;
80 /// EvaluateDefined - Process a 'defined(sym)' expression.
81 static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
82 bool ValueLive, Preprocessor &PP) {
84 Result.setBegin(PeekTok.getLocation());
86 // Get the next token, don't expand it.
87 PP.LexUnexpandedNonComment(PeekTok);
89 // Two options, it can either be a pp-identifier or a (.
90 SourceLocation LParenLoc;
91 if (PeekTok.is(tok::l_paren)) {
92 // Found a paren, remember we saw it and skip it.
93 LParenLoc = PeekTok.getLocation();
94 PP.LexUnexpandedNonComment(PeekTok);
97 if (PeekTok.is(tok::code_completion)) {
98 if (PP.getCodeCompletionHandler())
99 PP.getCodeCompletionHandler()->CodeCompleteMacroName(false);
100 PP.setCodeCompletionReached();
101 PP.LexUnexpandedNonComment(PeekTok);
104 // If we don't have a pp-identifier now, this is an error.
105 if ((II = PeekTok.getIdentifierInfo()) == 0) {
106 PP.Diag(PeekTok, diag::err_pp_defined_requires_identifier);
110 // Otherwise, we got an identifier, is it defined to something?
111 Result.Val = II->hasMacroDefinition();
112 Result.Val.setIsUnsigned(false); // Result is signed intmax_t.
114 // If there is a macro, mark it used.
115 if (Result.Val != 0 && ValueLive) {
116 MacroInfo *Macro = PP.getMacroInfo(II);
117 PP.markMacroAsUsed(Macro);
120 // Invoke the 'defined' callback.
121 if (PPCallbacks *Callbacks = PP.getPPCallbacks())
122 Callbacks->Defined(PeekTok);
124 // If we are in parens, ensure we have a trailing ).
125 if (LParenLoc.isValid()) {
126 // Consume identifier.
127 Result.setEnd(PeekTok.getLocation());
128 PP.LexUnexpandedNonComment(PeekTok);
130 if (PeekTok.isNot(tok::r_paren)) {
131 PP.Diag(PeekTok.getLocation(), diag::err_pp_missing_rparen) << "defined";
132 PP.Diag(LParenLoc, diag::note_matching) << "(";
136 Result.setEnd(PeekTok.getLocation());
137 PP.LexNonComment(PeekTok);
139 // Consume identifier.
140 Result.setEnd(PeekTok.getLocation());
141 PP.LexNonComment(PeekTok);
144 // Success, remember that we saw defined(X).
145 DT.State = DefinedTracker::DefinedMacro;
150 /// EvaluateValue - Evaluate the token PeekTok (and any others needed) and
151 /// return the computed value in Result. Return true if there was an error
152 /// parsing. This function also returns information about the form of the
153 /// expression in DT. See above for information on what DT means.
155 /// If ValueLive is false, then this value is being evaluated in a context where
156 /// the result is not used. As such, avoid diagnostics that relate to
158 static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT,
159 bool ValueLive, Preprocessor &PP) {
160 DT.State = DefinedTracker::Unknown;
162 if (PeekTok.is(tok::code_completion)) {
163 if (PP.getCodeCompletionHandler())
164 PP.getCodeCompletionHandler()->CodeCompletePreprocessorExpression();
165 PP.setCodeCompletionReached();
166 PP.LexNonComment(PeekTok);
169 // If this token's spelling is a pp-identifier, check to see if it is
170 // 'defined' or if it is a macro. Note that we check here because many
171 // keywords are pp-identifiers, so we can't check the kind.
172 if (IdentifierInfo *II = PeekTok.getIdentifierInfo()) {
173 // Handle "defined X" and "defined(X)".
174 if (II->isStr("defined"))
175 return(EvaluateDefined(Result, PeekTok, DT, ValueLive, PP));
177 // If this identifier isn't 'defined' or one of the special
178 // preprocessor keywords and it wasn't macro expanded, it turns
179 // into a simple 0, unless it is the C++ keyword "true", in which case it
182 PP.Diag(PeekTok, diag::warn_pp_undef_identifier) << II;
183 Result.Val = II->getTokenID() == tok::kw_true;
184 Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0.
185 Result.setRange(PeekTok.getLocation());
186 PP.LexNonComment(PeekTok);
190 switch (PeekTok.getKind()) {
191 default: // Non-value token.
192 PP.Diag(PeekTok, diag::err_pp_expr_bad_token_start_expr);
196 // If there is no expression, report and exit.
197 PP.Diag(PeekTok, diag::err_pp_expected_value_in_expr);
199 case tok::numeric_constant: {
200 llvm::SmallString<64> IntegerBuffer;
201 bool NumberInvalid = false;
202 StringRef Spelling = PP.getSpelling(PeekTok, IntegerBuffer,
205 return true; // a diagnostic was already reported
207 NumericLiteralParser Literal(Spelling.begin(), Spelling.end(),
208 PeekTok.getLocation(), PP);
209 if (Literal.hadError)
210 return true; // a diagnostic was already reported.
212 if (Literal.isFloatingLiteral() || Literal.isImaginary) {
213 PP.Diag(PeekTok, diag::err_pp_illegal_floating_literal);
216 assert(Literal.isIntegerLiteral() && "Unknown ppnumber");
218 // long long is a C99 feature.
219 if (!PP.getLangOptions().C99 && Literal.isLongLong)
220 PP.Diag(PeekTok, PP.getLangOptions().CPlusPlus0x ?
221 diag::warn_cxx98_compat_longlong : diag::ext_longlong);
223 // Parse the integer literal into Result.
224 if (Literal.GetIntegerValue(Result.Val)) {
225 // Overflow parsing integer literal.
226 if (ValueLive) PP.Diag(PeekTok, diag::warn_integer_too_large);
227 Result.Val.setIsUnsigned(true);
229 // Set the signedness of the result to match whether there was a U suffix
231 Result.Val.setIsUnsigned(Literal.isUnsigned);
233 // Detect overflow based on whether the value is signed. If signed
234 // and if the value is too large, emit a warning "integer constant is so
235 // large that it is unsigned" e.g. on 12345678901234567890 where intmax_t
237 if (!Literal.isUnsigned && Result.Val.isNegative()) {
238 // Don't warn for a hex literal: 0x8000..0 shouldn't warn.
239 if (ValueLive && Literal.getRadix() != 16)
240 PP.Diag(PeekTok, diag::warn_integer_too_large_for_signed);
241 Result.Val.setIsUnsigned(true);
245 // Consume the token.
246 Result.setRange(PeekTok.getLocation());
247 PP.LexNonComment(PeekTok);
250 case tok::char_constant: // 'x'
251 case tok::wide_char_constant: { // L'x'
252 case tok::utf16_char_constant: // u'x'
253 case tok::utf32_char_constant: // U'x'
254 llvm::SmallString<32> CharBuffer;
255 bool CharInvalid = false;
256 StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid);
260 CharLiteralParser Literal(ThisTok.begin(), ThisTok.end(),
261 PeekTok.getLocation(), PP, PeekTok.getKind());
262 if (Literal.hadError())
263 return true; // A diagnostic was already emitted.
265 // Character literals are always int or wchar_t, expand to intmax_t.
266 const TargetInfo &TI = PP.getTargetInfo();
268 if (Literal.isMultiChar())
269 NumBits = TI.getIntWidth();
270 else if (Literal.isWide())
271 NumBits = TI.getWCharWidth();
272 else if (Literal.isUTF16())
273 NumBits = TI.getChar16Width();
274 else if (Literal.isUTF32())
275 NumBits = TI.getChar32Width();
277 NumBits = TI.getCharWidth();
280 llvm::APSInt Val(NumBits);
282 Val = Literal.getValue();
283 // Set the signedness. UTF-16 and UTF-32 are always unsigned
284 if (!Literal.isUTF16() && !Literal.isUTF32())
285 Val.setIsUnsigned(!PP.getLangOptions().CharIsSigned);
287 if (Result.Val.getBitWidth() > Val.getBitWidth()) {
288 Result.Val = Val.extend(Result.Val.getBitWidth());
290 assert(Result.Val.getBitWidth() == Val.getBitWidth() &&
291 "intmax_t smaller than char/wchar_t?");
295 // Consume the token.
296 Result.setRange(PeekTok.getLocation());
297 PP.LexNonComment(PeekTok);
301 SourceLocation Start = PeekTok.getLocation();
302 PP.LexNonComment(PeekTok); // Eat the (.
303 // Parse the value and if there are any binary operators involved, parse
305 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
307 // If this is a silly value like (X), which doesn't need parens, check for
309 if (PeekTok.is(tok::r_paren)) {
310 // Just use DT unmodified as our result.
312 // Otherwise, we have something like (x+y), and we consumed '(x'.
313 if (EvaluateDirectiveSubExpr(Result, 1, PeekTok, ValueLive, PP))
316 if (PeekTok.isNot(tok::r_paren)) {
317 PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_rparen)
318 << Result.getRange();
319 PP.Diag(Start, diag::note_matching) << "(";
322 DT.State = DefinedTracker::Unknown;
324 Result.setRange(Start, PeekTok.getLocation());
325 PP.LexNonComment(PeekTok); // Eat the ).
329 SourceLocation Start = PeekTok.getLocation();
330 // Unary plus doesn't modify the value.
331 PP.LexNonComment(PeekTok);
332 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
333 Result.setBegin(Start);
337 SourceLocation Loc = PeekTok.getLocation();
338 PP.LexNonComment(PeekTok);
339 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
340 Result.setBegin(Loc);
342 // C99 6.5.3.3p3: The sign of the result matches the sign of the operand.
343 Result.Val = -Result.Val;
345 // -MININT is the only thing that overflows. Unsigned never overflows.
346 bool Overflow = !Result.isUnsigned() && Result.Val.isMinSignedValue();
348 // If this operator is live and overflowed, report the issue.
349 if (Overflow && ValueLive)
350 PP.Diag(Loc, diag::warn_pp_expr_overflow) << Result.getRange();
352 DT.State = DefinedTracker::Unknown;
357 SourceLocation Start = PeekTok.getLocation();
358 PP.LexNonComment(PeekTok);
359 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
360 Result.setBegin(Start);
362 // C99 6.5.3.3p4: The sign of the result matches the sign of the operand.
363 Result.Val = ~Result.Val;
364 DT.State = DefinedTracker::Unknown;
369 SourceLocation Start = PeekTok.getLocation();
370 PP.LexNonComment(PeekTok);
371 if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true;
372 Result.setBegin(Start);
373 Result.Val = !Result.Val;
374 // C99 6.5.3.3p5: The sign of the result is 'int', aka it is signed.
375 Result.Val.setIsUnsigned(false);
377 if (DT.State == DefinedTracker::DefinedMacro)
378 DT.State = DefinedTracker::NotDefinedMacro;
379 else if (DT.State == DefinedTracker::NotDefinedMacro)
380 DT.State = DefinedTracker::DefinedMacro;
384 // FIXME: Handle #assert
390 /// getPrecedence - Return the precedence of the specified binary operator
391 /// token. This returns:
392 /// ~0 - Invalid token.
393 /// 14 -> 3 - various operators.
395 static unsigned getPrecedence(tok::TokenKind Kind) {
400 case tok::star: return 14;
402 case tok::minus: return 13;
404 case tok::greatergreater: return 12;
407 case tok::greaterequal:
408 case tok::greater: return 11;
409 case tok::exclaimequal:
410 case tok::equalequal: return 10;
411 case tok::amp: return 9;
412 case tok::caret: return 8;
413 case tok::pipe: return 7;
414 case tok::ampamp: return 6;
415 case tok::pipepipe: return 5;
416 case tok::question: return 4;
417 case tok::comma: return 3;
418 case tok::colon: return 2;
419 case tok::r_paren: return 0;// Lowest priority, end of expr.
420 case tok::eod: return 0;// Lowest priority, end of directive.
425 /// EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is
426 /// PeekTok, and whose precedence is PeekPrec. This returns the result in LHS.
428 /// If ValueLive is false, then this value is being evaluated in a context where
429 /// the result is not used. As such, avoid diagnostics that relate to
430 /// evaluation, such as division by zero warnings.
431 static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec,
432 Token &PeekTok, bool ValueLive,
434 unsigned PeekPrec = getPrecedence(PeekTok.getKind());
435 // If this token isn't valid, report the error.
436 if (PeekPrec == ~0U) {
437 PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop)
443 // If this token has a lower precedence than we are allowed to parse, return
444 // it so that higher levels of the recursion can parse it.
445 if (PeekPrec < MinPrec)
448 tok::TokenKind Operator = PeekTok.getKind();
450 // If this is a short-circuiting operator, see if the RHS of the operator is
451 // dead. Note that this cannot just clobber ValueLive. Consider
452 // "0 && 1 ? 4 : 1 / 0", which is parsed as "(0 && 1) ? 4 : (1 / 0)". In
453 // this example, the RHS of the && being dead does not make the rest of the
456 if (Operator == tok::ampamp && LHS.Val == 0)
457 RHSIsLive = false; // RHS of "0 && x" is dead.
458 else if (Operator == tok::pipepipe && LHS.Val != 0)
459 RHSIsLive = false; // RHS of "1 || x" is dead.
460 else if (Operator == tok::question && LHS.Val == 0)
461 RHSIsLive = false; // RHS (x) of "0 ? x : y" is dead.
463 RHSIsLive = ValueLive;
465 // Consume the operator, remembering the operator's location for reporting.
466 SourceLocation OpLoc = PeekTok.getLocation();
467 PP.LexNonComment(PeekTok);
469 PPValue RHS(LHS.getBitWidth());
470 // Parse the RHS of the operator.
472 if (EvaluateValue(RHS, PeekTok, DT, RHSIsLive, PP)) return true;
474 // Remember the precedence of this operator and get the precedence of the
475 // operator immediately to the right of the RHS.
476 unsigned ThisPrec = PeekPrec;
477 PeekPrec = getPrecedence(PeekTok.getKind());
479 // If this token isn't valid, report the error.
480 if (PeekPrec == ~0U) {
481 PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop)
486 // Decide whether to include the next binop in this subexpression. For
487 // example, when parsing x+y*z and looking at '*', we want to recursively
488 // handle y*z as a single subexpression. We do this because the precedence
489 // of * is higher than that of +. The only strange case we have to handle
490 // here is for the ?: operator, where the precedence is actually lower than
491 // the LHS of the '?'. The grammar rule is:
493 // conditional-expression ::=
494 // logical-OR-expression ? expression : conditional-expression
495 // where 'expression' is actually comma-expression.
497 if (Operator == tok::question)
498 // The RHS of "?" should be maximally consumed as an expression.
499 RHSPrec = getPrecedence(tok::comma);
500 else // All others should munch while higher precedence.
501 RHSPrec = ThisPrec+1;
503 if (PeekPrec >= RHSPrec) {
504 if (EvaluateDirectiveSubExpr(RHS, RHSPrec, PeekTok, RHSIsLive, PP))
506 PeekPrec = getPrecedence(PeekTok.getKind());
508 assert(PeekPrec <= ThisPrec && "Recursion didn't work!");
510 // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if
511 // either operand is unsigned.
512 llvm::APSInt Res(LHS.getBitWidth());
514 case tok::question: // No UAC for x and y in "x ? y : z".
515 case tok::lessless: // Shift amount doesn't UAC with shift value.
516 case tok::greatergreater: // Shift amount doesn't UAC with shift value.
517 case tok::comma: // Comma operands are not subject to UACs.
518 case tok::pipepipe: // Logical || does not do UACs.
519 case tok::ampamp: // Logical && does not do UACs.
522 Res.setIsUnsigned(LHS.isUnsigned()|RHS.isUnsigned());
523 // If this just promoted something from signed to unsigned, and if the
524 // value was negative, warn about it.
525 if (ValueLive && Res.isUnsigned()) {
526 if (!LHS.isUnsigned() && LHS.Val.isNegative())
527 PP.Diag(OpLoc, diag::warn_pp_convert_lhs_to_positive)
528 << LHS.Val.toString(10, true) + " to " +
529 LHS.Val.toString(10, false)
530 << LHS.getRange() << RHS.getRange();
531 if (!RHS.isUnsigned() && RHS.Val.isNegative())
532 PP.Diag(OpLoc, diag::warn_pp_convert_rhs_to_positive)
533 << RHS.Val.toString(10, true) + " to " +
534 RHS.Val.toString(10, false)
535 << LHS.getRange() << RHS.getRange();
537 LHS.Val.setIsUnsigned(Res.isUnsigned());
538 RHS.Val.setIsUnsigned(Res.isUnsigned());
541 bool Overflow = false;
543 default: llvm_unreachable("Unknown operator token!");
546 Res = LHS.Val % RHS.Val;
547 else if (ValueLive) {
548 PP.Diag(OpLoc, diag::err_pp_remainder_by_zero)
549 << LHS.getRange() << RHS.getRange();
555 if (LHS.Val.isSigned())
556 Res = llvm::APSInt(LHS.Val.sdiv_ov(RHS.Val, Overflow), false);
558 Res = LHS.Val / RHS.Val;
559 } else if (ValueLive) {
560 PP.Diag(OpLoc, diag::err_pp_division_by_zero)
561 << LHS.getRange() << RHS.getRange();
568 Res = llvm::APSInt(LHS.Val.smul_ov(RHS.Val, Overflow), false);
570 Res = LHS.Val * RHS.Val;
572 case tok::lessless: {
573 // Determine whether overflow is about to happen.
574 unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue());
575 if (LHS.isUnsigned()) {
576 Overflow = ShAmt >= LHS.Val.getBitWidth();
578 ShAmt = LHS.Val.getBitWidth()-1;
579 Res = LHS.Val << ShAmt;
581 Res = llvm::APSInt(LHS.Val.sshl_ov(ShAmt, Overflow), false);
585 case tok::greatergreater: {
586 // Determine whether overflow is about to happen.
587 unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue());
588 if (ShAmt >= LHS.getBitWidth())
589 Overflow = true, ShAmt = LHS.getBitWidth()-1;
590 Res = LHS.Val >> ShAmt;
594 if (LHS.isUnsigned())
595 Res = LHS.Val + RHS.Val;
597 Res = llvm::APSInt(LHS.Val.sadd_ov(RHS.Val, Overflow), false);
600 if (LHS.isUnsigned())
601 Res = LHS.Val - RHS.Val;
603 Res = llvm::APSInt(LHS.Val.ssub_ov(RHS.Val, Overflow), false);
606 Res = LHS.Val <= RHS.Val;
607 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
610 Res = LHS.Val < RHS.Val;
611 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
613 case tok::greaterequal:
614 Res = LHS.Val >= RHS.Val;
615 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
618 Res = LHS.Val > RHS.Val;
619 Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed)
621 case tok::exclaimequal:
622 Res = LHS.Val != RHS.Val;
623 Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed)
625 case tok::equalequal:
626 Res = LHS.Val == RHS.Val;
627 Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed)
630 Res = LHS.Val & RHS.Val;
633 Res = LHS.Val ^ RHS.Val;
636 Res = LHS.Val | RHS.Val;
639 Res = (LHS.Val != 0 && RHS.Val != 0);
640 Res.setIsUnsigned(false); // C99 6.5.13p3, result is always int (signed)
643 Res = (LHS.Val != 0 || RHS.Val != 0);
644 Res.setIsUnsigned(false); // C99 6.5.14p3, result is always int (signed)
647 // Comma is invalid in pp expressions in c89/c++ mode, but is valid in C99
648 // if not being evaluated.
649 if (!PP.getLangOptions().C99 || ValueLive)
650 PP.Diag(OpLoc, diag::ext_pp_comma_expr)
651 << LHS.getRange() << RHS.getRange();
652 Res = RHS.Val; // LHS = LHS,RHS -> RHS.
654 case tok::question: {
655 // Parse the : part of the expression.
656 if (PeekTok.isNot(tok::colon)) {
657 PP.Diag(PeekTok.getLocation(), diag::err_expected_colon)
658 << LHS.getRange(), RHS.getRange();
659 PP.Diag(OpLoc, diag::note_matching) << "?";
663 PP.LexNonComment(PeekTok);
665 // Evaluate the value after the :.
666 bool AfterColonLive = ValueLive && LHS.Val == 0;
667 PPValue AfterColonVal(LHS.getBitWidth());
669 if (EvaluateValue(AfterColonVal, PeekTok, DT, AfterColonLive, PP))
672 // Parse anything after the : with the same precedence as ?. We allow
673 // things of equal precedence because ?: is right associative.
674 if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec,
675 PeekTok, AfterColonLive, PP))
678 // Now that we have the condition, the LHS and the RHS of the :, evaluate.
679 Res = LHS.Val != 0 ? RHS.Val : AfterColonVal.Val;
680 RHS.setEnd(AfterColonVal.getRange().getEnd());
682 // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if
683 // either operand is unsigned.
684 Res.setIsUnsigned(RHS.isUnsigned() | AfterColonVal.isUnsigned());
686 // Figure out the precedence of the token after the : part.
687 PeekPrec = getPrecedence(PeekTok.getKind());
691 // Don't allow :'s to float around without being part of ?: exprs.
692 PP.Diag(OpLoc, diag::err_pp_colon_without_question)
693 << LHS.getRange() << RHS.getRange();
697 // If this operator is live and overflowed, report the issue.
698 if (Overflow && ValueLive)
699 PP.Diag(OpLoc, diag::warn_pp_expr_overflow)
700 << LHS.getRange() << RHS.getRange();
702 // Put the result back into 'LHS' for our next iteration.
704 LHS.setEnd(RHS.getRange().getEnd());
710 /// EvaluateDirectiveExpression - Evaluate an integer constant expression that
711 /// may occur after a #if or #elif directive. If the expression is equivalent
712 /// to "!defined(X)" return X in IfNDefMacro.
714 EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro) {
715 // Save the current state of 'DisableMacroExpansion' and reset it to false. If
716 // 'DisableMacroExpansion' is true, then we must be in a macro argument list
717 // in which case a directive is undefined behavior. We want macros to be able
718 // to recursively expand in order to get more gcc-list behavior, so we force
719 // DisableMacroExpansion to false and restore it when we're done parsing the
721 bool DisableMacroExpansionAtStartOfDirective = DisableMacroExpansion;
722 DisableMacroExpansion = false;
724 // Peek ahead one token.
728 // C99 6.10.1p3 - All expressions are evaluated as intmax_t or uintmax_t.
729 unsigned BitWidth = getTargetInfo().getIntMaxTWidth();
731 PPValue ResVal(BitWidth);
733 if (EvaluateValue(ResVal, Tok, DT, true, *this)) {
734 // Parse error, skip the rest of the macro line.
735 if (Tok.isNot(tok::eod))
736 DiscardUntilEndOfDirective();
738 // Restore 'DisableMacroExpansion'.
739 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
743 // If we are at the end of the expression after just parsing a value, there
744 // must be no (unparenthesized) binary operators involved, so we can exit
746 if (Tok.is(tok::eod)) {
747 // If the expression we parsed was of the form !defined(macro), return the
748 // macro in IfNDefMacro.
749 if (DT.State == DefinedTracker::NotDefinedMacro)
750 IfNDefMacro = DT.TheMacro;
752 // Restore 'DisableMacroExpansion'.
753 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
754 return ResVal.Val != 0;
757 // Otherwise, we must have a binary operator (e.g. "#if 1 < 2"), so parse the
758 // operator and the stuff after it.
759 if (EvaluateDirectiveSubExpr(ResVal, getPrecedence(tok::question),
761 // Parse error, skip the rest of the macro line.
762 if (Tok.isNot(tok::eod))
763 DiscardUntilEndOfDirective();
765 // Restore 'DisableMacroExpansion'.
766 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
770 // If we aren't at the tok::eod token, something bad happened, like an extra
772 if (Tok.isNot(tok::eod)) {
773 Diag(Tok, diag::err_pp_expected_eol);
774 DiscardUntilEndOfDirective();
777 // Restore 'DisableMacroExpansion'.
778 DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective;
779 return ResVal.Val != 0;