diff options
Diffstat (limited to 'clang/lib')
| -rw-r--r-- | clang/lib/AST/ExprConstant.cpp | 12 | ||||
| -rw-r--r-- | clang/lib/CodeGen/CGExprConstant.cpp | 40 |
2 files changed, 33 insertions, 19 deletions
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 0e1fb98bf77..3efd8dc6a60 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -10312,12 +10312,6 @@ bool Expr::EvaluateAsBooleanCondition(bool &Result, HandleConversionToBool(Scratch.Val, Result); } -static bool hasUnacceptableSideEffect(Expr::EvalStatus &Result, - Expr::SideEffectsKind SEK) { - return (SEK < Expr::SE_AllowSideEffects && Result.HasSideEffects) || - (SEK < Expr::SE_AllowUndefinedBehavior && Result.HasUndefinedBehavior); -} - bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx, SideEffectsKind AllowSideEffects) const { if (!getType()->isIntegralOrEnumerationType()) @@ -10325,7 +10319,7 @@ bool Expr::EvaluateAsInt(APSInt &Result, const ASTContext &Ctx, EvalResult ExprResult; if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isInt() || - hasUnacceptableSideEffect(ExprResult, AllowSideEffects)) + ExprResult.hasUnacceptableSideEffect(AllowSideEffects)) return false; Result = ExprResult.Val.getInt(); @@ -10339,7 +10333,7 @@ bool Expr::EvaluateAsFloat(APFloat &Result, const ASTContext &Ctx, EvalResult ExprResult; if (!EvaluateAsRValue(ExprResult, Ctx) || !ExprResult.Val.isFloat() || - hasUnacceptableSideEffect(ExprResult, AllowSideEffects)) + ExprResult.hasUnacceptableSideEffect(AllowSideEffects)) return false; Result = ExprResult.Val.getFloat(); @@ -10417,7 +10411,7 @@ bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx, bool Expr::isEvaluatable(const ASTContext &Ctx, SideEffectsKind SEK) const { EvalResult Result; return EvaluateAsRValue(Result, Ctx) && - !hasUnacceptableSideEffect(Result, SEK); + !Result.hasUnacceptableSideEffect(SEK); } APSInt Expr::EvaluateKnownConstInt(const ASTContext &Ctx, diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp index 7b076ea3e65..ae05df1be58 100644 --- a/clang/lib/CodeGen/CGExprConstant.cpp +++ b/clang/lib/CodeGen/CGExprConstant.cpp @@ -1392,20 +1392,40 @@ static QualType getNonMemoryType(CodeGenModule &CGM, QualType type) { return type; } +/// Checks if the specified initializer is equivalent to zero initialization. +static bool isZeroInitializer(ConstantEmitter &CE, const Expr *Init) { + if (auto *E = dyn_cast_or_null<CXXConstructExpr>(Init)) { + CXXConstructorDecl *CD = E->getConstructor(); + return CD->isDefaultConstructor() && CD->isTrivial(); + } + + if (auto *IL = dyn_cast_or_null<InitListExpr>(Init)) { + for (auto I : IL->inits()) + if (!isZeroInitializer(CE, I)) + return false; + if (const Expr *Filler = IL->getArrayFiller()) + return isZeroInitializer(CE, Filler); + return true; + } + + QualType InitTy = Init->getType(); + if (InitTy->isIntegralOrEnumerationType() || InitTy->isPointerType()) { + Expr::EvalResult Result; + if (Init->EvaluateAsRValue(Result, CE.CGM.getContext()) && + !Result.hasUnacceptableSideEffect(Expr::SE_NoSideEffects)) + return (Result.Val.isInt() && Result.Val.getInt().isNullValue()) || + (Result.Val.isLValue() && Result.Val.isNullPointer()); + } + + return false; +} + llvm::Constant *ConstantEmitter::tryEmitPrivateForVarInit(const VarDecl &D) { // Make a quick check if variable can be default NULL initialized // and avoid going through rest of code which may do, for c++11, // initialization of memory to all NULLs. - if (!D.hasLocalStorage()) { - QualType Ty = CGM.getContext().getBaseElementType(D.getType()); - if (Ty->isRecordType()) - if (const CXXConstructExpr *E = - dyn_cast_or_null<CXXConstructExpr>(D.getInit())) { - const CXXConstructorDecl *CD = E->getConstructor(); - if (CD->isTrivial() && CD->isDefaultConstructor()) - return CGM.EmitNullConstant(D.getType()); - } - } + if (!D.hasLocalStorage() && isZeroInitializer(*this, D.getInit())) + return CGM.EmitNullConstant(D.getType()); QualType destType = D.getType(); |
