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Diffstat (limited to 'clang/lib/Lex/PPExpressions.cpp')
| -rw-r--r-- | clang/lib/Lex/PPExpressions.cpp | 786 |
1 files changed, 786 insertions, 0 deletions
diff --git a/clang/lib/Lex/PPExpressions.cpp b/clang/lib/Lex/PPExpressions.cpp new file mode 100644 index 0000000..7cac63e --- /dev/null +++ b/clang/lib/Lex/PPExpressions.cpp @@ -0,0 +1,786 @@ +//===--- PPExpressions.cpp - Preprocessor Expression Evaluation -----------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements the Preprocessor::EvaluateDirectiveExpression method, +// which parses and evaluates integer constant expressions for #if directives. +// +//===----------------------------------------------------------------------===// +// +// FIXME: implement testing for #assert's. +// +//===----------------------------------------------------------------------===// + +#include "clang/Lex/Preprocessor.h" +#include "clang/Lex/MacroInfo.h" +#include "clang/Lex/LiteralSupport.h" +#include "clang/Lex/CodeCompletionHandler.h" +#include "clang/Basic/TargetInfo.h" +#include "clang/Lex/LexDiagnostic.h" +#include "llvm/ADT/APSInt.h" +#include "llvm/Support/ErrorHandling.h" +using namespace clang; + +namespace { + +/// PPValue - Represents the value of a subexpression of a preprocessor +/// conditional and the source range covered by it. +class PPValue { + SourceRange Range; +public: + llvm::APSInt Val; + + // Default ctor - Construct an 'invalid' PPValue. + PPValue(unsigned BitWidth) : Val(BitWidth) {} + + unsigned getBitWidth() const { return Val.getBitWidth(); } + bool isUnsigned() const { return Val.isUnsigned(); } + + const SourceRange &getRange() const { return Range; } + + void setRange(SourceLocation L) { Range.setBegin(L); Range.setEnd(L); } + void setRange(SourceLocation B, SourceLocation E) { + Range.setBegin(B); Range.setEnd(E); + } + void setBegin(SourceLocation L) { Range.setBegin(L); } + void setEnd(SourceLocation L) { Range.setEnd(L); } +}; + +} + +static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, + Token &PeekTok, bool ValueLive, + Preprocessor &PP); + +/// DefinedTracker - This struct is used while parsing expressions to keep track +/// of whether !defined(X) has been seen. +/// +/// With this simple scheme, we handle the basic forms: +/// !defined(X) and !defined X +/// but we also trivially handle (silly) stuff like: +/// !!!defined(X) and +!defined(X) and !+!+!defined(X) and !(defined(X)). +struct DefinedTracker { + /// Each time a Value is evaluated, it returns information about whether the + /// parsed value is of the form defined(X), !defined(X) or is something else. + enum TrackerState { + DefinedMacro, // defined(X) + NotDefinedMacro, // !defined(X) + Unknown // Something else. + } State; + /// TheMacro - When the state is DefinedMacro or NotDefinedMacro, this + /// indicates the macro that was checked. + IdentifierInfo *TheMacro; +}; + +/// EvaluateDefined - Process a 'defined(sym)' expression. +static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT, + bool ValueLive, Preprocessor &PP) { + IdentifierInfo *II; + Result.setBegin(PeekTok.getLocation()); + + // Get the next token, don't expand it. + PP.LexUnexpandedNonComment(PeekTok); + + // Two options, it can either be a pp-identifier or a (. + SourceLocation LParenLoc; + if (PeekTok.is(tok::l_paren)) { + // Found a paren, remember we saw it and skip it. + LParenLoc = PeekTok.getLocation(); + PP.LexUnexpandedNonComment(PeekTok); + } + + if (PeekTok.is(tok::code_completion)) { + if (PP.getCodeCompletionHandler()) + PP.getCodeCompletionHandler()->CodeCompleteMacroName(false); + PP.setCodeCompletionReached(); + PP.LexUnexpandedNonComment(PeekTok); + } + + // If we don't have a pp-identifier now, this is an error. + if ((II = PeekTok.getIdentifierInfo()) == 0) { + PP.Diag(PeekTok, diag::err_pp_defined_requires_identifier); + return true; + } + + // Otherwise, we got an identifier, is it defined to something? + Result.Val = II->hasMacroDefinition(); + Result.Val.setIsUnsigned(false); // Result is signed intmax_t. + + // If there is a macro, mark it used. + if (Result.Val != 0 && ValueLive) { + MacroInfo *Macro = PP.getMacroInfo(II); + PP.markMacroAsUsed(Macro); + } + + // Invoke the 'defined' callback. + if (PPCallbacks *Callbacks = PP.getPPCallbacks()) + Callbacks->Defined(PeekTok); + + // If we are in parens, ensure we have a trailing ). + if (LParenLoc.isValid()) { + // Consume identifier. + Result.setEnd(PeekTok.getLocation()); + PP.LexUnexpandedNonComment(PeekTok); + + if (PeekTok.isNot(tok::r_paren)) { + PP.Diag(PeekTok.getLocation(), diag::err_pp_missing_rparen) << "defined"; + PP.Diag(LParenLoc, diag::note_matching) << "("; + return true; + } + // Consume the ). + Result.setEnd(PeekTok.getLocation()); + PP.LexNonComment(PeekTok); + } else { + // Consume identifier. + Result.setEnd(PeekTok.getLocation()); + PP.LexNonComment(PeekTok); + } + + // Success, remember that we saw defined(X). + DT.State = DefinedTracker::DefinedMacro; + DT.TheMacro = II; + return false; +} + +/// EvaluateValue - Evaluate the token PeekTok (and any others needed) and +/// return the computed value in Result. Return true if there was an error +/// parsing. This function also returns information about the form of the +/// expression in DT. See above for information on what DT means. +/// +/// If ValueLive is false, then this value is being evaluated in a context where +/// the result is not used. As such, avoid diagnostics that relate to +/// evaluation. +static bool EvaluateValue(PPValue &Result, Token &PeekTok, DefinedTracker &DT, + bool ValueLive, Preprocessor &PP) { + DT.State = DefinedTracker::Unknown; + + if (PeekTok.is(tok::code_completion)) { + if (PP.getCodeCompletionHandler()) + PP.getCodeCompletionHandler()->CodeCompletePreprocessorExpression(); + PP.setCodeCompletionReached(); + PP.LexNonComment(PeekTok); + } + + // If this token's spelling is a pp-identifier, check to see if it is + // 'defined' or if it is a macro. Note that we check here because many + // keywords are pp-identifiers, so we can't check the kind. + if (IdentifierInfo *II = PeekTok.getIdentifierInfo()) { + // Handle "defined X" and "defined(X)". + if (II->isStr("defined")) + return(EvaluateDefined(Result, PeekTok, DT, ValueLive, PP)); + + // If this identifier isn't 'defined' or one of the special + // preprocessor keywords and it wasn't macro expanded, it turns + // into a simple 0, unless it is the C++ keyword "true", in which case it + // turns into "1". + if (ValueLive) + PP.Diag(PeekTok, diag::warn_pp_undef_identifier) << II; + Result.Val = II->getTokenID() == tok::kw_true; + Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0. + Result.setRange(PeekTok.getLocation()); + PP.LexNonComment(PeekTok); + return false; + } + + switch (PeekTok.getKind()) { + default: // Non-value token. + PP.Diag(PeekTok, diag::err_pp_expr_bad_token_start_expr); + return true; + case tok::eod: + case tok::r_paren: + // If there is no expression, report and exit. + PP.Diag(PeekTok, diag::err_pp_expected_value_in_expr); + return true; + case tok::numeric_constant: { + SmallString<64> IntegerBuffer; + bool NumberInvalid = false; + StringRef Spelling = PP.getSpelling(PeekTok, IntegerBuffer, + &NumberInvalid); + if (NumberInvalid) + return true; // a diagnostic was already reported + + NumericLiteralParser Literal(Spelling.begin(), Spelling.end(), + PeekTok.getLocation(), PP); + if (Literal.hadError) + return true; // a diagnostic was already reported. + + if (Literal.isFloatingLiteral() || Literal.isImaginary) { + PP.Diag(PeekTok, diag::err_pp_illegal_floating_literal); + return true; + } + assert(Literal.isIntegerLiteral() && "Unknown ppnumber"); + + // Complain about, and drop, any ud-suffix. + if (Literal.hasUDSuffix()) + PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*integer*/1; + + // long long is a C99 feature. + if (!PP.getLangOpts().C99 && Literal.isLongLong) + PP.Diag(PeekTok, PP.getLangOpts().CPlusPlus0x ? + diag::warn_cxx98_compat_longlong : diag::ext_longlong); + + // Parse the integer literal into Result. + if (Literal.GetIntegerValue(Result.Val)) { + // Overflow parsing integer literal. + if (ValueLive) PP.Diag(PeekTok, diag::warn_integer_too_large); + Result.Val.setIsUnsigned(true); + } else { + // Set the signedness of the result to match whether there was a U suffix + // or not. + Result.Val.setIsUnsigned(Literal.isUnsigned); + + // Detect overflow based on whether the value is signed. If signed + // and if the value is too large, emit a warning "integer constant is so + // large that it is unsigned" e.g. on 12345678901234567890 where intmax_t + // is 64-bits. + if (!Literal.isUnsigned && Result.Val.isNegative()) { + // Don't warn for a hex literal: 0x8000..0 shouldn't warn. + if (ValueLive && Literal.getRadix() != 16) + PP.Diag(PeekTok, diag::warn_integer_too_large_for_signed); + Result.Val.setIsUnsigned(true); + } + } + + // Consume the token. + Result.setRange(PeekTok.getLocation()); + PP.LexNonComment(PeekTok); + return false; + } + case tok::char_constant: // 'x' + case tok::wide_char_constant: { // L'x' + case tok::utf16_char_constant: // u'x' + case tok::utf32_char_constant: // U'x' + // Complain about, and drop, any ud-suffix. + if (PeekTok.hasUDSuffix()) + PP.Diag(PeekTok, diag::err_pp_invalid_udl) << /*character*/0; + + SmallString<32> CharBuffer; + bool CharInvalid = false; + StringRef ThisTok = PP.getSpelling(PeekTok, CharBuffer, &CharInvalid); + if (CharInvalid) + return true; + + CharLiteralParser Literal(ThisTok.begin(), ThisTok.end(), + PeekTok.getLocation(), PP, PeekTok.getKind()); + if (Literal.hadError()) + return true; // A diagnostic was already emitted. + + // Character literals are always int or wchar_t, expand to intmax_t. + const TargetInfo &TI = PP.getTargetInfo(); + unsigned NumBits; + if (Literal.isMultiChar()) + NumBits = TI.getIntWidth(); + else if (Literal.isWide()) + NumBits = TI.getWCharWidth(); + else if (Literal.isUTF16()) + NumBits = TI.getChar16Width(); + else if (Literal.isUTF32()) + NumBits = TI.getChar32Width(); + else + NumBits = TI.getCharWidth(); + + // Set the width. + llvm::APSInt Val(NumBits); + // Set the value. + Val = Literal.getValue(); + // Set the signedness. UTF-16 and UTF-32 are always unsigned + if (!Literal.isUTF16() && !Literal.isUTF32()) + Val.setIsUnsigned(!PP.getLangOpts().CharIsSigned); + + if (Result.Val.getBitWidth() > Val.getBitWidth()) { + Result.Val = Val.extend(Result.Val.getBitWidth()); + } else { + assert(Result.Val.getBitWidth() == Val.getBitWidth() && + "intmax_t smaller than char/wchar_t?"); + Result.Val = Val; + } + + // Consume the token. + Result.setRange(PeekTok.getLocation()); + PP.LexNonComment(PeekTok); + return false; + } + case tok::l_paren: { + SourceLocation Start = PeekTok.getLocation(); + PP.LexNonComment(PeekTok); // Eat the (. + // Parse the value and if there are any binary operators involved, parse + // them. + if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; + + // If this is a silly value like (X), which doesn't need parens, check for + // !(defined X). + if (PeekTok.is(tok::r_paren)) { + // Just use DT unmodified as our result. + } else { + // Otherwise, we have something like (x+y), and we consumed '(x'. + if (EvaluateDirectiveSubExpr(Result, 1, PeekTok, ValueLive, PP)) + return true; + + if (PeekTok.isNot(tok::r_paren)) { + PP.Diag(PeekTok.getLocation(), diag::err_pp_expected_rparen) + << Result.getRange(); + PP.Diag(Start, diag::note_matching) << "("; + return true; + } + DT.State = DefinedTracker::Unknown; + } + Result.setRange(Start, PeekTok.getLocation()); + PP.LexNonComment(PeekTok); // Eat the ). + return false; + } + case tok::plus: { + SourceLocation Start = PeekTok.getLocation(); + // Unary plus doesn't modify the value. + PP.LexNonComment(PeekTok); + if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; + Result.setBegin(Start); + return false; + } + case tok::minus: { + SourceLocation Loc = PeekTok.getLocation(); + PP.LexNonComment(PeekTok); + if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; + Result.setBegin(Loc); + + // C99 6.5.3.3p3: The sign of the result matches the sign of the operand. + Result.Val = -Result.Val; + + // -MININT is the only thing that overflows. Unsigned never overflows. + bool Overflow = !Result.isUnsigned() && Result.Val.isMinSignedValue(); + + // If this operator is live and overflowed, report the issue. + if (Overflow && ValueLive) + PP.Diag(Loc, diag::warn_pp_expr_overflow) << Result.getRange(); + + DT.State = DefinedTracker::Unknown; + return false; + } + + case tok::tilde: { + SourceLocation Start = PeekTok.getLocation(); + PP.LexNonComment(PeekTok); + if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; + Result.setBegin(Start); + + // C99 6.5.3.3p4: The sign of the result matches the sign of the operand. + Result.Val = ~Result.Val; + DT.State = DefinedTracker::Unknown; + return false; + } + + case tok::exclaim: { + SourceLocation Start = PeekTok.getLocation(); + PP.LexNonComment(PeekTok); + if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; + Result.setBegin(Start); + Result.Val = !Result.Val; + // C99 6.5.3.3p5: The sign of the result is 'int', aka it is signed. + Result.Val.setIsUnsigned(false); + + if (DT.State == DefinedTracker::DefinedMacro) + DT.State = DefinedTracker::NotDefinedMacro; + else if (DT.State == DefinedTracker::NotDefinedMacro) + DT.State = DefinedTracker::DefinedMacro; + return false; + } + + // FIXME: Handle #assert + } +} + + + +/// getPrecedence - Return the precedence of the specified binary operator +/// token. This returns: +/// ~0 - Invalid token. +/// 14 -> 3 - various operators. +/// 0 - 'eod' or ')' +static unsigned getPrecedence(tok::TokenKind Kind) { + switch (Kind) { + default: return ~0U; + case tok::percent: + case tok::slash: + case tok::star: return 14; + case tok::plus: + case tok::minus: return 13; + case tok::lessless: + case tok::greatergreater: return 12; + case tok::lessequal: + case tok::less: + case tok::greaterequal: + case tok::greater: return 11; + case tok::exclaimequal: + case tok::equalequal: return 10; + case tok::amp: return 9; + case tok::caret: return 8; + case tok::pipe: return 7; + case tok::ampamp: return 6; + case tok::pipepipe: return 5; + case tok::question: return 4; + case tok::comma: return 3; + case tok::colon: return 2; + case tok::r_paren: return 0;// Lowest priority, end of expr. + case tok::eod: return 0;// Lowest priority, end of directive. + } +} + + +/// EvaluateDirectiveSubExpr - Evaluate the subexpression whose first token is +/// PeekTok, and whose precedence is PeekPrec. This returns the result in LHS. +/// +/// If ValueLive is false, then this value is being evaluated in a context where +/// the result is not used. As such, avoid diagnostics that relate to +/// evaluation, such as division by zero warnings. +static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, + Token &PeekTok, bool ValueLive, + Preprocessor &PP) { + unsigned PeekPrec = getPrecedence(PeekTok.getKind()); + // If this token isn't valid, report the error. + if (PeekPrec == ~0U) { + PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop) + << LHS.getRange(); + return true; + } + + while (1) { + // If this token has a lower precedence than we are allowed to parse, return + // it so that higher levels of the recursion can parse it. + if (PeekPrec < MinPrec) + return false; + + tok::TokenKind Operator = PeekTok.getKind(); + + // If this is a short-circuiting operator, see if the RHS of the operator is + // dead. Note that this cannot just clobber ValueLive. Consider + // "0 && 1 ? 4 : 1 / 0", which is parsed as "(0 && 1) ? 4 : (1 / 0)". In + // this example, the RHS of the && being dead does not make the rest of the + // expr dead. + bool RHSIsLive; + if (Operator == tok::ampamp && LHS.Val == 0) + RHSIsLive = false; // RHS of "0 && x" is dead. + else if (Operator == tok::pipepipe && LHS.Val != 0) + RHSIsLive = false; // RHS of "1 || x" is dead. + else if (Operator == tok::question && LHS.Val == 0) + RHSIsLive = false; // RHS (x) of "0 ? x : y" is dead. + else + RHSIsLive = ValueLive; + + // Consume the operator, remembering the operator's location for reporting. + SourceLocation OpLoc = PeekTok.getLocation(); + PP.LexNonComment(PeekTok); + + PPValue RHS(LHS.getBitWidth()); + // Parse the RHS of the operator. + DefinedTracker DT; + if (EvaluateValue(RHS, PeekTok, DT, RHSIsLive, PP)) return true; + + // Remember the precedence of this operator and get the precedence of the + // operator immediately to the right of the RHS. + unsigned ThisPrec = PeekPrec; + PeekPrec = getPrecedence(PeekTok.getKind()); + + // If this token isn't valid, report the error. + if (PeekPrec == ~0U) { + PP.Diag(PeekTok.getLocation(), diag::err_pp_expr_bad_token_binop) + << RHS.getRange(); + return true; + } + + // Decide whether to include the next binop in this subexpression. For + // example, when parsing x+y*z and looking at '*', we want to recursively + // handle y*z as a single subexpression. We do this because the precedence + // of * is higher than that of +. The only strange case we have to handle + // here is for the ?: operator, where the precedence is actually lower than + // the LHS of the '?'. The grammar rule is: + // + // conditional-expression ::= + // logical-OR-expression ? expression : conditional-expression + // where 'expression' is actually comma-expression. + unsigned RHSPrec; + if (Operator == tok::question) + // The RHS of "?" should be maximally consumed as an expression. + RHSPrec = getPrecedence(tok::comma); + else // All others should munch while higher precedence. + RHSPrec = ThisPrec+1; + + if (PeekPrec >= RHSPrec) { + if (EvaluateDirectiveSubExpr(RHS, RHSPrec, PeekTok, RHSIsLive, PP)) + return true; + PeekPrec = getPrecedence(PeekTok.getKind()); + } + assert(PeekPrec <= ThisPrec && "Recursion didn't work!"); + + // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if + // either operand is unsigned. + llvm::APSInt Res(LHS.getBitWidth()); + switch (Operator) { + case tok::question: // No UAC for x and y in "x ? y : z". + case tok::lessless: // Shift amount doesn't UAC with shift value. + case tok::greatergreater: // Shift amount doesn't UAC with shift value. + case tok::comma: // Comma operands are not subject to UACs. + case tok::pipepipe: // Logical || does not do UACs. + case tok::ampamp: // Logical && does not do UACs. + break; // No UAC + default: + Res.setIsUnsigned(LHS.isUnsigned()|RHS.isUnsigned()); + // If this just promoted something from signed to unsigned, and if the + // value was negative, warn about it. + if (ValueLive && Res.isUnsigned()) { + if (!LHS.isUnsigned() && LHS.Val.isNegative()) + PP.Diag(OpLoc, diag::warn_pp_convert_lhs_to_positive) + << LHS.Val.toString(10, true) + " to " + + LHS.Val.toString(10, false) + << LHS.getRange() << RHS.getRange(); + if (!RHS.isUnsigned() && RHS.Val.isNegative()) + PP.Diag(OpLoc, diag::warn_pp_convert_rhs_to_positive) + << RHS.Val.toString(10, true) + " to " + + RHS.Val.toString(10, false) + << LHS.getRange() << RHS.getRange(); + } + LHS.Val.setIsUnsigned(Res.isUnsigned()); + RHS.Val.setIsUnsigned(Res.isUnsigned()); + } + + bool Overflow = false; + switch (Operator) { + default: llvm_unreachable("Unknown operator token!"); + case tok::percent: + if (RHS.Val != 0) + Res = LHS.Val % RHS.Val; + else if (ValueLive) { + PP.Diag(OpLoc, diag::err_pp_remainder_by_zero) + << LHS.getRange() << RHS.getRange(); + return true; + } + break; + case tok::slash: + if (RHS.Val != 0) { + if (LHS.Val.isSigned()) + Res = llvm::APSInt(LHS.Val.sdiv_ov(RHS.Val, Overflow), false); + else + Res = LHS.Val / RHS.Val; + } else if (ValueLive) { + PP.Diag(OpLoc, diag::err_pp_division_by_zero) + << LHS.getRange() << RHS.getRange(); + return true; + } + break; + + case tok::star: + if (Res.isSigned()) + Res = llvm::APSInt(LHS.Val.smul_ov(RHS.Val, Overflow), false); + else + Res = LHS.Val * RHS.Val; + break; + case tok::lessless: { + // Determine whether overflow is about to happen. + unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue()); + if (LHS.isUnsigned()) { + Overflow = ShAmt >= LHS.Val.getBitWidth(); + if (Overflow) + ShAmt = LHS.Val.getBitWidth()-1; + Res = LHS.Val << ShAmt; + } else { + Res = llvm::APSInt(LHS.Val.sshl_ov(ShAmt, Overflow), false); + } + break; + } + case tok::greatergreater: { + // Determine whether overflow is about to happen. + unsigned ShAmt = static_cast<unsigned>(RHS.Val.getLimitedValue()); + if (ShAmt >= LHS.getBitWidth()) + Overflow = true, ShAmt = LHS.getBitWidth()-1; + Res = LHS.Val >> ShAmt; + break; + } + case tok::plus: + if (LHS.isUnsigned()) + Res = LHS.Val + RHS.Val; + else + Res = llvm::APSInt(LHS.Val.sadd_ov(RHS.Val, Overflow), false); + break; + case tok::minus: + if (LHS.isUnsigned()) + Res = LHS.Val - RHS.Val; + else + Res = llvm::APSInt(LHS.Val.ssub_ov(RHS.Val, Overflow), false); + break; + case tok::lessequal: + Res = LHS.Val <= RHS.Val; + Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) + break; + case tok::less: + Res = LHS.Val < RHS.Val; + Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) + break; + case tok::greaterequal: + Res = LHS.Val >= RHS.Val; + Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) + break; + case tok::greater: + Res = LHS.Val > RHS.Val; + Res.setIsUnsigned(false); // C99 6.5.8p6, result is always int (signed) + break; + case tok::exclaimequal: + Res = LHS.Val != RHS.Val; + Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed) + break; + case tok::equalequal: + Res = LHS.Val == RHS.Val; + Res.setIsUnsigned(false); // C99 6.5.9p3, result is always int (signed) + break; + case tok::amp: + Res = LHS.Val & RHS.Val; + break; + case tok::caret: + Res = LHS.Val ^ RHS.Val; + break; + case tok::pipe: + Res = LHS.Val | RHS.Val; + break; + case tok::ampamp: + Res = (LHS.Val != 0 && RHS.Val != 0); + Res.setIsUnsigned(false); // C99 6.5.13p3, result is always int (signed) + break; + case tok::pipepipe: + Res = (LHS.Val != 0 || RHS.Val != 0); + Res.setIsUnsigned(false); // C99 6.5.14p3, result is always int (signed) + break; + case tok::comma: + // Comma is invalid in pp expressions in c89/c++ mode, but is valid in C99 + // if not being evaluated. + if (!PP.getLangOpts().C99 || ValueLive) + PP.Diag(OpLoc, diag::ext_pp_comma_expr) + << LHS.getRange() << RHS.getRange(); + Res = RHS.Val; // LHS = LHS,RHS -> RHS. + break; + case tok::question: { + // Parse the : part of the expression. + if (PeekTok.isNot(tok::colon)) { + PP.Diag(PeekTok.getLocation(), diag::err_expected_colon) + << LHS.getRange(), RHS.getRange(); + PP.Diag(OpLoc, diag::note_matching) << "?"; + return true; + } + // Consume the :. + PP.LexNonComment(PeekTok); + + // Evaluate the value after the :. + bool AfterColonLive = ValueLive && LHS.Val == 0; + PPValue AfterColonVal(LHS.getBitWidth()); + DefinedTracker DT; + if (EvaluateValue(AfterColonVal, PeekTok, DT, AfterColonLive, PP)) + return true; + + // Parse anything after the : with the same precedence as ?. We allow + // things of equal precedence because ?: is right associative. + if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec, + PeekTok, AfterColonLive, PP)) + return true; + + // Now that we have the condition, the LHS and the RHS of the :, evaluate. + Res = LHS.Val != 0 ? RHS.Val : AfterColonVal.Val; + RHS.setEnd(AfterColonVal.getRange().getEnd()); + + // Usual arithmetic conversions (C99 6.3.1.8p1): result is unsigned if + // either operand is unsigned. + Res.setIsUnsigned(RHS.isUnsigned() | AfterColonVal.isUnsigned()); + + // Figure out the precedence of the token after the : part. + PeekPrec = getPrecedence(PeekTok.getKind()); + break; + } + case tok::colon: + // Don't allow :'s to float around without being part of ?: exprs. + PP.Diag(OpLoc, diag::err_pp_colon_without_question) + << LHS.getRange() << RHS.getRange(); + return true; + } + + // If this operator is live and overflowed, report the issue. + if (Overflow && ValueLive) + PP.Diag(OpLoc, diag::warn_pp_expr_overflow) + << LHS.getRange() << RHS.getRange(); + + // Put the result back into 'LHS' for our next iteration. + LHS.Val = Res; + LHS.setEnd(RHS.getRange().getEnd()); + } +} + +/// EvaluateDirectiveExpression - Evaluate an integer constant expression that +/// may occur after a #if or #elif directive. If the expression is equivalent +/// to "!defined(X)" return X in IfNDefMacro. +bool Preprocessor:: +EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro) { + // Save the current state of 'DisableMacroExpansion' and reset it to false. If + // 'DisableMacroExpansion' is true, then we must be in a macro argument list + // in which case a directive is undefined behavior. We want macros to be able + // to recursively expand in order to get more gcc-list behavior, so we force + // DisableMacroExpansion to false and restore it when we're done parsing the + // expression. + bool DisableMacroExpansionAtStartOfDirective = DisableMacroExpansion; + DisableMacroExpansion = false; + + // Peek ahead one token. + Token Tok; + LexNonComment(Tok); + + // C99 6.10.1p3 - All expressions are evaluated as intmax_t or uintmax_t. + unsigned BitWidth = getTargetInfo().getIntMaxTWidth(); + + PPValue ResVal(BitWidth); + DefinedTracker DT; + if (EvaluateValue(ResVal, Tok, DT, true, *this)) { + // Parse error, skip the rest of the macro line. + if (Tok.isNot(tok::eod)) + DiscardUntilEndOfDirective(); + + // Restore 'DisableMacroExpansion'. + DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; + return false; + } + + // If we are at the end of the expression after just parsing a value, there + // must be no (unparenthesized) binary operators involved, so we can exit + // directly. + if (Tok.is(tok::eod)) { + // If the expression we parsed was of the form !defined(macro), return the + // macro in IfNDefMacro. + if (DT.State == DefinedTracker::NotDefinedMacro) + IfNDefMacro = DT.TheMacro; + + // Restore 'DisableMacroExpansion'. + DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; + return ResVal.Val != 0; + } + + // Otherwise, we must have a binary operator (e.g. "#if 1 < 2"), so parse the + // operator and the stuff after it. + if (EvaluateDirectiveSubExpr(ResVal, getPrecedence(tok::question), + Tok, true, *this)) { + // Parse error, skip the rest of the macro line. + if (Tok.isNot(tok::eod)) + DiscardUntilEndOfDirective(); + + // Restore 'DisableMacroExpansion'. + DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; + return false; + } + + // If we aren't at the tok::eod token, something bad happened, like an extra + // ')' token. + if (Tok.isNot(tok::eod)) { + Diag(Tok, diag::err_pp_expected_eol); + DiscardUntilEndOfDirective(); + } + + // Restore 'DisableMacroExpansion'. + DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; + return ResVal.Val != 0; +} |