From 9e4451359e49b07daff391ed20fbf47b63df9bf2 Mon Sep 17 00:00:00 2001 From: Richard Smith Date: Thu, 19 Sep 2019 22:00:16 +0000 Subject: Model converted constant expressions as full-expressions. This is groundwork for C++20's P0784R7, where non-trivial destructors can be constexpr, so we need ExprWithCleanups markers in constant expressions. No functionality change intended. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@372359 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Sema/SemaOverload.cpp | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-) (limited to 'lib/Sema/SemaOverload.cpp') diff --git a/lib/Sema/SemaOverload.cpp b/lib/Sema/SemaOverload.cpp index 6887cdd7ee..b8e1d2c035 100644 --- a/lib/Sema/SemaOverload.cpp +++ b/lib/Sema/SemaOverload.cpp @@ -257,8 +257,18 @@ isPointerConversionToVoidPointer(ASTContext& Context) const { /// Skip any implicit casts which could be either part of a narrowing conversion /// or after one in an implicit conversion. -static const Expr *IgnoreNarrowingConversion(const Expr *Converted) { - while (const ImplicitCastExpr *ICE = dyn_cast(Converted)) { +static const Expr *IgnoreNarrowingConversion(ASTContext &Ctx, + const Expr *Converted) { + // We can have cleanups wrapping the converted expression; these need to be + // preserved so that destructors run if necessary. + if (auto *EWC = dyn_cast(Converted)) { + Expr *Inner = + const_cast(IgnoreNarrowingConversion(Ctx, EWC->getSubExpr())); + return ExprWithCleanups::Create(Ctx, Inner, EWC->cleanupsHaveSideEffects(), + EWC->getObjects()); + } + + while (auto *ICE = dyn_cast(Converted)) { switch (ICE->getCastKind()) { case CK_NoOp: case CK_IntegralCast: @@ -332,7 +342,7 @@ NarrowingKind StandardConversionSequence::getNarrowingKind( if (IgnoreFloatToIntegralConversion) return NK_Not_Narrowing; llvm::APSInt IntConstantValue; - const Expr *Initializer = IgnoreNarrowingConversion(Converted); + const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted); assert(Initializer && "Unknown conversion expression"); // If it's value-dependent, we can't tell whether it's narrowing. @@ -370,7 +380,7 @@ NarrowingKind StandardConversionSequence::getNarrowingKind( if (FromType->isRealFloatingType() && ToType->isRealFloatingType() && Ctx.getFloatingTypeOrder(FromType, ToType) == 1) { // FromType is larger than ToType. - const Expr *Initializer = IgnoreNarrowingConversion(Converted); + const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted); // If it's value-dependent, we can't tell whether it's narrowing. if (Initializer->isValueDependent()) @@ -416,7 +426,7 @@ NarrowingKind StandardConversionSequence::getNarrowingKind( (FromSigned && !ToSigned)) { // Not all values of FromType can be represented in ToType. llvm::APSInt InitializerValue; - const Expr *Initializer = IgnoreNarrowingConversion(Converted); + const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted); // If it's value-dependent, we can't tell whether it's narrowing. if (Initializer->isValueDependent()) @@ -5465,6 +5475,14 @@ static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From, if (Result.isInvalid()) return Result; + // C++2a [intro.execution]p5: + // A full-expression is [...] a constant-expression [...] + Result = + S.ActOnFinishFullExpr(Result.get(), From->getExprLoc(), + /*DiscardedValue=*/false, /*IsConstexpr=*/true); + if (Result.isInvalid()) + return Result; + // Check for a narrowing implicit conversion. APValue PreNarrowingValue; QualType PreNarrowingType; -- cgit v1.2.1