//===--- PPExpressions.cpp - Preprocessor Expression Evaluation -----------===// // // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. // See https://llvm.org/LICENSE.txt for license information. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception // //===----------------------------------------------------------------------===// // // 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/Basic/IdentifierTable.h" #include "clang/Basic/SourceLocation.h" #include "clang/Basic/SourceManager.h" #include "clang/Basic/TargetInfo.h" #include "clang/Basic/TokenKinds.h" #include "clang/Lex/CodeCompletionHandler.h" #include "clang/Lex/LexDiagnostic.h" #include "clang/Lex/LiteralSupport.h" #include "clang/Lex/MacroInfo.h" #include "clang/Lex/PPCallbacks.h" #include "clang/Lex/Preprocessor.h" #include "clang/Lex/Token.h" #include "llvm/ADT/APSInt.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringExtras.h" #include "llvm/ADT/StringRef.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/SaveAndRestore.h" #include 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; IdentifierInfo *II; public: llvm::APSInt Val; // Default ctor - Construct an 'invalid' PPValue. PPValue(unsigned BitWidth) : Val(BitWidth) {} // If this value was produced by directly evaluating an identifier, produce // that identifier. IdentifierInfo *getIdentifier() const { return II; } void setIdentifier(IdentifierInfo *II) { this->II = II; } unsigned getBitWidth() const { return Val.getBitWidth(); } bool isUnsigned() const { return Val.isUnsigned(); } 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); } }; } // end anonymous namespace static bool EvaluateDirectiveSubExpr(PPValue &LHS, unsigned MinPrec, Token &PeekTok, bool ValueLive, bool &IncludedUndefinedIds, 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; bool IncludedUndefinedIds = false; }; /// EvaluateDefined - Process a 'defined(sym)' expression. static bool EvaluateDefined(PPValue &Result, Token &PeekTok, DefinedTracker &DT, bool ValueLive, Preprocessor &PP) { SourceLocation beginLoc(PeekTok.getLocation()); Result.setBegin(beginLoc); // 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 (PP.CheckMacroName(PeekTok, MU_Other)) return true; // Otherwise, we got an identifier, is it defined to something? IdentifierInfo *II = PeekTok.getIdentifierInfo(); MacroDefinition Macro = PP.getMacroDefinition(II); Result.Val = !!Macro; Result.Val.setIsUnsigned(false); // Result is signed intmax_t. DT.IncludedUndefinedIds = !Macro; // If there is a macro, mark it used. if (Result.Val != 0 && ValueLive) PP.markMacroAsUsed(Macro.getMacroInfo()); // Save macro token for callback. Token macroToken(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_expected_after) << "'defined'" << tok::r_paren; PP.Diag(LParenLoc, diag::note_matching) << tok::l_paren; return true; } // Consume the ). PP.LexNonComment(PeekTok); Result.setEnd(PeekTok.getLocation()); } else { // Consume identifier. Result.setEnd(PeekTok.getLocation()); PP.LexNonComment(PeekTok); } // [cpp.cond]p4: // Prior to evaluation, macro invocations in the list of preprocessing // tokens that will become the controlling constant expression are replaced // (except for those macro names modified by the 'defined' unary operator), // just as in normal text. If the token 'defined' is generated as a result // of this replacement process or use of the 'defined' unary operator does // not match one of the two specified forms prior to macro replacement, the // behavior is undefined. // This isn't an idle threat, consider this program: // #define FOO // #define BAR defined(FOO) // #if BAR // ... // #else // ... // #endif // clang and gcc will pick the #if branch while Visual Studio will take the // #else branch. Emit a warning about this undefined behavior. if (beginLoc.isMacroID()) { bool IsFunctionTypeMacro = PP.getSourceManager() .getSLocEntry(PP.getSourceManager().getFileID(beginLoc)) .getExpansion() .isFunctionMacroExpansion(); // For object-type macros, it's easy to replace // #define FOO defined(BAR) // with // #if defined(BAR) // #define FOO 1 // #else // #define FOO 0 // #endif // and doing so makes sense since compilers handle this differently in // practice (see example further up). But for function-type macros, // there is no good way to write // # define FOO(x) (defined(M_ ## x) && M_ ## x) // in a different way, and compilers seem to agree on how to behave here. // So warn by default on object-type macros, but only warn in -pedantic // mode on function-type macros. if (IsFunctionTypeMacro) PP.Diag(beginLoc, diag::warn_defined_in_function_type_macro); else PP.Diag(beginLoc, diag::warn_defined_in_object_type_macro); } // Invoke the 'defined' callback. if (PPCallbacks *Callbacks = PP.getPPCallbacks()) { Callbacks->Defined(macroToken, Macro, SourceRange(beginLoc, PeekTok.getLocation())); } // 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; Result.setIdentifier(nullptr); if (PeekTok.is(tok::code_completion)) { if (PP.getCodeCompletionHandler()) PP.getCodeCompletionHandler()->CodeCompletePreprocessorExpression(); PP.setCodeCompletionReached(); PP.LexNonComment(PeekTok); } switch (PeekTok.getKind()) { default: // 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 (!II->isCPlusPlusOperatorKeyword()) { // 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 if (ValueLive) { PP.Diag(PeekTok, diag::warn_pp_undef_identifier) << II; const DiagnosticsEngine &DiagEngine = PP.getDiagnostics(); // If 'Wundef' is enabled, do not emit 'undef-prefix' diagnostics. if (DiagEngine.isIgnored(diag::warn_pp_undef_identifier, PeekTok.getLocation())) { const std::vector UndefPrefixes = DiagEngine.getDiagnosticOptions().UndefPrefixes; const StringRef IdentifierName = II->getName(); if (llvm::any_of(UndefPrefixes, [&IdentifierName](const std::string &Prefix) { return IdentifierName.startswith(Prefix); })) PP.Diag(PeekTok, diag::warn_pp_undef_prefix) << AddFlagValue{llvm::join(UndefPrefixes, ",")} << II; } } Result.Val = 0; Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0. Result.setIdentifier(II); Result.setRange(PeekTok.getLocation()); DT.IncludedUndefinedIds = true; PP.LexNonComment(PeekTok); return false; } } 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, PeekTok.getLocation(), PP.getSourceManager(), PP.getLangOpts(), PP.getTargetInfo(), PP.getDiagnostics()); 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 or C++11 feature. if (!PP.getLangOpts().C99 && Literal.isLongLong) { if (PP.getLangOpts().CPlusPlus) PP.Diag(PeekTok, PP.getLangOpts().CPlusPlus11 ? diag::warn_cxx98_compat_longlong : diag::ext_cxx11_longlong); else PP.Diag(PeekTok, diag::ext_c99_longlong); } // Parse the integer literal into Result. if (Literal.GetIntegerValue(Result.Val)) { // Overflow parsing integer literal. if (ValueLive) PP.Diag(PeekTok, diag::err_integer_literal_too_large) << /* Unsigned */ 1; 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()) { // Octal, hexadecimal, and binary literals are implicitly unsigned if // the value does not fit into a signed integer type. if (ValueLive && Literal.getRadix() == 10) PP.Diag(PeekTok, diag::ext_integer_literal_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::utf8_char_constant: // u8'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 // char or char8_t 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.isWide()) Val.setIsUnsigned(!TargetInfo::isTypeSigned(TI.getWCharType())); else 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, DT.IncludedUndefinedIds, 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) << tok::l_paren; return true; } DT.State = DefinedTracker::Unknown; } Result.setRange(Start, PeekTok.getLocation()); Result.setIdentifier(nullptr); 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); Result.setIdentifier(nullptr); return false; } case tok::minus: { SourceLocation Loc = PeekTok.getLocation(); PP.LexNonComment(PeekTok); if (EvaluateValue(Result, PeekTok, DT, ValueLive, PP)) return true; Result.setBegin(Loc); Result.setIdentifier(nullptr); // 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); Result.setIdentifier(nullptr); // 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); Result.setIdentifier(nullptr); if (DT.State == DefinedTracker::DefinedMacro) DT.State = DefinedTracker::NotDefinedMacro; else if (DT.State == DefinedTracker::NotDefinedMacro) DT.State = DefinedTracker::DefinedMacro; return false; } case tok::kw_true: case tok::kw_false: Result.Val = PeekTok.getKind() == tok::kw_true; Result.Val.setIsUnsigned(false); // "0" is signed intmax_t 0. Result.setIdentifier(PeekTok.getIdentifierInfo()); Result.setRange(PeekTok.getLocation()); PP.LexNonComment(PeekTok); 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. } } static void diagnoseUnexpectedOperator(Preprocessor &PP, PPValue &LHS, Token &Tok) { if (Tok.is(tok::l_paren) && LHS.getIdentifier()) PP.Diag(LHS.getRange().getBegin(), diag::err_pp_expr_bad_token_lparen) << LHS.getIdentifier(); else PP.Diag(Tok.getLocation(), diag::err_pp_expr_bad_token_binop) << LHS.getRange(); } /// 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, bool &IncludedUndefinedIds, Preprocessor &PP) { unsigned PeekPrec = getPrecedence(PeekTok.getKind()); // If this token isn't valid, report the error. if (PeekPrec == ~0U) { diagnoseUnexpectedOperator(PP, LHS, PeekTok); return true; } while (true) { // 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; IncludedUndefinedIds = DT.IncludedUndefinedIds; // 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) { diagnoseUnexpectedOperator(PP, RHS, PeekTok); 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, IncludedUndefinedIds, 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_to_positive) << 0 << 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_to_positive) << 1 << 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. if (LHS.isUnsigned()) Res = LHS.Val.ushl_ov(RHS.Val, Overflow); else Res = llvm::APSInt(LHS.Val.sshl_ov(RHS.Val, Overflow), false); break; } case tok::greatergreater: { // Determine whether overflow is about to happen. unsigned ShAmt = static_cast(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) << tok::colon << LHS.getRange() << RHS.getRange(); PP.Diag(OpLoc, diag::note_matching) << tok::question; 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, IncludedUndefinedIds, 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()); RHS.setIdentifier(nullptr); } } /// 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. Preprocessor::DirectiveEvalResult Preprocessor::EvaluateDirectiveExpression(IdentifierInfo *&IfNDefMacro) { SaveAndRestore PPDir(ParsingIfOrElifDirective, true); // 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; SourceLocation ExprStartLoc = SourceMgr.getExpansionLoc(Tok.getLocation()); if (EvaluateValue(ResVal, Tok, DT, true, *this)) { // Parse error, skip the rest of the macro line. SourceRange ConditionRange = ExprStartLoc; if (Tok.isNot(tok::eod)) ConditionRange = DiscardUntilEndOfDirective(); // Restore 'DisableMacroExpansion'. DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; // We cannot trust the source range from the value because there was a // parse error. Track the range manually -- the end of the directive is the // end of the condition range. return {false, DT.IncludedUndefinedIds, {ExprStartLoc, ConditionRange.getEnd()}}; } // 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, DT.IncludedUndefinedIds, ResVal.getRange()}; } // 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, DT.IncludedUndefinedIds, *this)) { // Parse error, skip the rest of the macro line. if (Tok.isNot(tok::eod)) DiscardUntilEndOfDirective(); // Restore 'DisableMacroExpansion'. DisableMacroExpansion = DisableMacroExpansionAtStartOfDirective; return {false, DT.IncludedUndefinedIds, ResVal.getRange()}; } // 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, DT.IncludedUndefinedIds, ResVal.getRange()}; }