r183283 - Model temporary lifetime-extension explicitly in the AST. Use this model to
Jordan Rose
jordan_rose at apple.com
Tue Jun 4 18:57:02 PDT 2013
When we get around to modeling non-trivial temporaries in the static analyzer, this will probably be very, very useful. Thanks for doing all this.
On Jun 4, 2013, at 17:46 , Richard Smith <richard-llvm at metafoo.co.uk> wrote:
> Author: rsmith
> Date: Tue Jun 4 19:46:14 2013
> New Revision: 183283
>
> URL: http://llvm.org/viewvc/llvm-project?rev=183283&view=rev
> Log:
> Model temporary lifetime-extension explicitly in the AST. Use this model to
> handle temporaries which have been lifetime-extended to static storage duration
> within constant expressions. This correctly handles nested lifetime extension
> (through reference members of aggregates in aggregate initializers) but
> non-constant-expression emission hasn't yet been updated to do the same.
>
> Modified:
> cfe/trunk/include/clang/AST/ASTContext.h
> cfe/trunk/include/clang/AST/Decl.h
> cfe/trunk/include/clang/AST/ExprCXX.h
> cfe/trunk/include/clang/AST/Stmt.h
> cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
> cfe/trunk/include/clang/Basic/Specifiers.h
> cfe/trunk/include/clang/Sema/Initialization.h
> cfe/trunk/lib/AST/ASTContext.cpp
> cfe/trunk/lib/AST/ASTDumper.cpp
> cfe/trunk/lib/AST/ExprConstant.cpp
> cfe/trunk/lib/CodeGen/CGExprConstant.cpp
> cfe/trunk/lib/CodeGen/CodeGenModule.cpp
> cfe/trunk/lib/CodeGen/CodeGenModule.h
> cfe/trunk/lib/Sema/SemaExpr.cpp
> cfe/trunk/lib/Sema/SemaInit.cpp
> cfe/trunk/lib/Serialization/ASTReaderStmt.cpp
> cfe/trunk/lib/Serialization/ASTWriterStmt.cpp
> cfe/trunk/test/CodeGenCXX/const-init-cxx11.cpp
> cfe/trunk/test/CodeGenCXX/const-init-cxx1y.cpp
> cfe/trunk/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
> cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
> cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp
>
> Modified: cfe/trunk/include/clang/AST/ASTContext.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ASTContext.h?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/ASTContext.h (original)
> +++ cfe/trunk/include/clang/AST/ASTContext.h Tue Jun 4 19:46:14 2013
> @@ -55,6 +55,7 @@ namespace clang {
> class ExternalASTSource;
> class ASTMutationListener;
> class IdentifierTable;
> + class MaterializeTemporaryExpr;
> class SelectorTable;
> class TargetInfo;
> class CXXABI;
> @@ -163,6 +164,11 @@ class ASTContext : public RefCountedBase
> llvm::DenseMap<const FunctionDecl*, FunctionDecl*>
> ClassScopeSpecializationPattern;
>
> + /// \brief Mapping from materialized temporaries with static storage duration
> + /// that appear in constant initializers to their evaluated values.
> + llvm::DenseMap<const MaterializeTemporaryExpr*, APValue>
> + MaterializedTemporaryValues;
> +
> /// \brief Representation of a "canonical" template template parameter that
> /// is used in canonical template names.
> class CanonicalTemplateTemplateParm : public llvm::FoldingSetNode {
> @@ -2117,7 +2123,12 @@ public:
> /// \brief Used by ParmVarDecl to retrieve on the side the
> /// index of the parameter when it exceeds the size of the normal bitfield.
> unsigned getParameterIndex(const ParmVarDecl *D) const;
> -
> +
> + /// \brief Get the storage for the constant value of a materialized temporary
> + /// of static storage duration.
> + APValue *getMaterializedTemporaryValue(const MaterializeTemporaryExpr *E,
> + bool MayCreate);
> +
> //===--------------------------------------------------------------------===//
> // Statistics
> //===--------------------------------------------------------------------===//
>
> Modified: cfe/trunk/include/clang/AST/Decl.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/Decl.h (original)
> +++ cfe/trunk/include/clang/AST/Decl.h Tue Jun 4 19:46:14 2013
> @@ -811,7 +811,7 @@ public:
> bool hasLocalStorage() const {
> if (getStorageClass() == SC_None)
> // Second check is for C++11 [dcl.stc]p4.
> - return !isFileVarDecl() && getTSCSpec() != TSCS_thread_local;
> + return !isFileVarDecl() && getTSCSpec() == TSCS_unspecified;
>
> // Return true for: Auto, Register.
> // Return false for: Extern, Static, PrivateExtern, OpenCLWorkGroupLocal.
> @@ -840,6 +840,12 @@ public:
> /// as static variables declared within a function.
> bool hasGlobalStorage() const { return !hasLocalStorage(); }
>
> + /// \brief Get the storage duration of this variable, per C++ [basid.stc].
> + StorageDuration getStorageDuration() const {
> + return hasLocalStorage() ? SD_Automatic :
> + getTSCSpec() ? SD_Thread : SD_Static;
> + }
> +
> /// Compute the language linkage.
> LanguageLinkage getLanguageLinkage() const;
>
>
> Modified: cfe/trunk/include/clang/AST/ExprCXX.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ExprCXX.h?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/ExprCXX.h (original)
> +++ cfe/trunk/include/clang/AST/ExprCXX.h Tue Jun 4 19:46:14 2013
> @@ -3824,30 +3824,60 @@ public:
> /// binds to the temporary. \c MaterializeTemporaryExprs are always glvalues
> /// (either an lvalue or an xvalue, depending on the kind of reference binding
> /// to it), maintaining the invariant that references always bind to glvalues.
> +///
> +/// Reference binding and copy-elision can both extend the lifetime of a
> +/// temporary. When either happens, the expression will also track the
> +/// declaration which is responsible for the lifetime extension.
> class MaterializeTemporaryExpr : public Expr {
> +public:
> /// \brief The temporary-generating expression whose value will be
> /// materialized.
> Stmt *Temporary;
>
> + /// \brief The declaration which lifetime-extended this reference, if any.
> + /// Either a VarDecl, or (for a ctor-initializer) a FieldDecl.
> + const ValueDecl *ExtendingDecl;
> +
> friend class ASTStmtReader;
> friend class ASTStmtWriter;
>
> public:
> MaterializeTemporaryExpr(QualType T, Expr *Temporary,
> - bool BoundToLvalueReference)
> + bool BoundToLvalueReference,
> + const ValueDecl *ExtendedBy)
> : Expr(MaterializeTemporaryExprClass, T,
> BoundToLvalueReference? VK_LValue : VK_XValue, OK_Ordinary,
> Temporary->isTypeDependent(), Temporary->isValueDependent(),
> Temporary->isInstantiationDependent(),
> Temporary->containsUnexpandedParameterPack()),
> - Temporary(Temporary) { }
> + Temporary(Temporary), ExtendingDecl(ExtendedBy) {
> + }
>
> MaterializeTemporaryExpr(EmptyShell Empty)
> : Expr(MaterializeTemporaryExprClass, Empty) { }
>
> /// \brief Retrieve the temporary-generating subexpression whose value will
> /// be materialized into a glvalue.
> - Expr *GetTemporaryExpr() const { return reinterpret_cast<Expr *>(Temporary); }
> + Expr *GetTemporaryExpr() const { return static_cast<Expr *>(Temporary); }
> +
> + /// \brief Retrieve the storage duration for the materialized temporary.
> + StorageDuration getStorageDuration() const {
> + if (!ExtendingDecl)
> + return SD_FullExpression;
> + // FIXME: This is not necessarily correct for a temporary materialized
> + // within a default initializer.
> + if (isa<FieldDecl>(ExtendingDecl))
> + return SD_Automatic;
> + return cast<VarDecl>(ExtendingDecl)->getStorageDuration();
> + }
> +
> + /// \brief Get the declaration which triggered the lifetime-extension of this
> + /// temporary, if any.
> + const ValueDecl *getExtendingDecl() const { return ExtendingDecl; }
> +
> + void setExtendingDecl(const ValueDecl *ExtendedBy) {
> + ExtendingDecl = ExtendedBy;
> + }
>
> /// \brief Determine whether this materialized temporary is bound to an
> /// lvalue reference; otherwise, it's bound to an rvalue reference.
>
> Modified: cfe/trunk/include/clang/AST/Stmt.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Stmt.h?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/Stmt.h (original)
> +++ cfe/trunk/include/clang/AST/Stmt.h Tue Jun 4 19:46:14 2013
> @@ -289,7 +289,7 @@ protected:
> /// \brief The number of arguments to this type trait.
> unsigned NumArgs : 32 - 8 - 1 - NumExprBits;
> };
> -
> +
> union {
> // FIXME: this is wasteful on 64-bit platforms.
> void *Aligner;
>
> Modified: cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td (original)
> +++ cfe/trunk/include/clang/Basic/DiagnosticASTKinds.td Tue Jun 4 19:46:14 2013
> @@ -117,6 +117,10 @@ def note_constexpr_access_inactive_union
> "%select{read of|assignment to|increment of|decrement of}0 "
> "member %1 of union with %select{active member %3|no active member}2 "
> "is not allowed in a constant expression">;
> +def note_constexpr_access_static_temporary : Note<
> + "%select{read of|assignment to|increment of|decrement of}0 temporary "
> + "is not allowed in a constant expression outside the expression that "
> + "created the temporary">;
> def note_constexpr_modify_global : Note<
> "a constant expression cannot modify an object that is visible outside "
> "that expression">;
>
> Modified: cfe/trunk/include/clang/Basic/Specifiers.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Specifiers.h?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/Specifiers.h (original)
> +++ cfe/trunk/include/clang/Basic/Specifiers.h Tue Jun 4 19:46:14 2013
> @@ -212,6 +212,14 @@ namespace clang {
> CC_IntelOclBicc // __attribute__((intel_ocl_bicc))
> };
>
> + /// \brief The storage duration for an object (per C++ [basic.stc]).
> + enum StorageDuration {
> + SD_FullExpression, ///< Full-expression storage duration (for temporaries).
> + SD_Automatic, ///< Automatic storage duration (most local variables).
> + SD_Thread, ///< Thread storage duration.
> + SD_Static, ///< Static storage duration.
> + SD_Dynamic ///< Dynamic storage duration.
> + };
> } // end namespace clang
>
> #endif // LLVM_CLANG_BASIC_SPECIFIERS_H
>
> Modified: cfe/trunk/include/clang/Sema/Initialization.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Initialization.h?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Sema/Initialization.h (original)
> +++ cfe/trunk/include/clang/Sema/Initialization.h Tue Jun 4 19:46:14 2013
> @@ -384,6 +384,13 @@ public:
> assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
> return SourceLocation::getFromRawEncoding(Capture.Location);
> }
> +
> + /// Dump a representation of the initialized entity to standard error,
> + /// for debugging purposes.
> + void dump() const;
> +
> +private:
> + unsigned dumpImpl(raw_ostream &OS) const;
> };
>
> /// \brief Describes the kind of initialization being performed, along with
>
> Modified: cfe/trunk/lib/AST/ASTContext.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTContext.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/ASTContext.cpp (original)
> +++ cfe/trunk/lib/AST/ASTContext.cpp Tue Jun 4 19:46:14 2013
> @@ -8029,6 +8029,19 @@ unsigned ASTContext::getParameterIndex(c
> return I->second;
> }
>
> +APValue *
> +ASTContext::getMaterializedTemporaryValue(const MaterializeTemporaryExpr *E,
> + bool MayCreate) {
> + assert(E && E->getStorageDuration() == SD_Static &&
> + "don't need to cache the computed value for this temporary");
> + if (MayCreate)
> + return &MaterializedTemporaryValues[E];
> +
> + llvm::DenseMap<const MaterializeTemporaryExpr *, APValue>::iterator I =
> + MaterializedTemporaryValues.find(E);
> + return I == MaterializedTemporaryValues.end() ? 0 : &I->second;
> +}
> +
> bool ASTContext::AtomicUsesUnsupportedLibcall(const AtomicExpr *E) const {
> const llvm::Triple &T = getTargetInfo().getTriple();
> if (!T.isOSDarwin())
>
> Modified: cfe/trunk/lib/AST/ASTDumper.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTDumper.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/ASTDumper.cpp (original)
> +++ cfe/trunk/lib/AST/ASTDumper.cpp Tue Jun 4 19:46:14 2013
> @@ -274,6 +274,7 @@ namespace {
> void VisitCXXFunctionalCastExpr(const CXXFunctionalCastExpr *Node);
> void VisitCXXConstructExpr(const CXXConstructExpr *Node);
> void VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *Node);
> + void VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *Node);
> void VisitExprWithCleanups(const ExprWithCleanups *Node);
> void VisitUnresolvedLookupExpr(const UnresolvedLookupExpr *Node);
> void dumpCXXTemporary(const CXXTemporary *Temporary);
> @@ -1682,6 +1683,15 @@ void ASTDumper::VisitCXXBindTemporaryExp
> dumpCXXTemporary(Node->getTemporary());
> }
>
> +void
> +ASTDumper::VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *Node) {
> + VisitExpr(Node);
> + if (const ValueDecl *VD = Node->getExtendingDecl()) {
> + OS << " extended by ";
> + dumpBareDeclRef(VD);
> + }
> +}
> +
> void ASTDumper::VisitExprWithCleanups(const ExprWithCleanups *Node) {
> VisitExpr(Node);
> for (unsigned i = 0, e = Node->getNumObjects(); i != e; ++i)
>
> Modified: cfe/trunk/lib/AST/ExprConstant.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/AST/ExprConstant.cpp (original)
> +++ cfe/trunk/lib/AST/ExprConstant.cpp Tue Jun 4 19:46:14 2013
> @@ -1001,6 +1001,10 @@ static bool IsGlobalLValue(APValue::LVal
> const CompoundLiteralExpr *CLE = cast<CompoundLiteralExpr>(E);
> return CLE->isFileScope() && CLE->isLValue();
> }
> + case Expr::MaterializeTemporaryExprClass:
> + // A materialized temporary might have been lifetime-extended to static
> + // storage duration.
> + return cast<MaterializeTemporaryExpr>(E)->getStorageDuration() == SD_Static;
> // A string literal has static storage duration.
> case Expr::StringLiteralClass:
> case Expr::PredefinedExprClass:
> @@ -1182,7 +1186,10 @@ const ValueDecl *GetLValueBaseDecl(const
> }
>
> static bool IsLiteralLValue(const LValue &Value) {
> - return Value.Base.dyn_cast<const Expr*>() && !Value.CallIndex;
> + if (Value.CallIndex)
> + return false;
> + const Expr *E = Value.Base.dyn_cast<const Expr*>();
> + return E && !isa<MaterializeTemporaryExpr>(E);
> }
>
> static bool IsWeakLValue(const LValue &Value) {
> @@ -2279,11 +2286,44 @@ CompleteObject findCompleteObject(EvalIn
> const Expr *Base = LVal.Base.dyn_cast<const Expr*>();
>
> if (!Frame) {
> - Info.Diag(E);
> - return CompleteObject();
> - }
> + if (const MaterializeTemporaryExpr *MTE =
> + dyn_cast<MaterializeTemporaryExpr>(Base)) {
> + assert(MTE->getStorageDuration() == SD_Static &&
> + "should have a frame for a non-global materialized temporary");
> +
> + // Per C++1y [expr.const]p2:
> + // an lvalue-to-rvalue conversion [is not allowed unless it applies to]
> + // - a [...] glvalue of integral or enumeration type that refers to
> + // a non-volatile const object [...]
> + // [...]
> + // - a [...] glvalue of literal type that refers to a non-volatile
> + // object whose lifetime began within the evaluation of e.
> + //
> + // C++11 misses the 'began within the evaluation of e' check and
> + // instead allows all temporaries, including things like:
> + // int &&r = 1;
> + // int x = ++r;
> + // constexpr int k = r;
> + // Therefore we use the C++1y rules in C++11 too.
> + const ValueDecl *VD = Info.EvaluatingDecl.dyn_cast<const ValueDecl*>();
> + const ValueDecl *ED = MTE->getExtendingDecl();
> + if (!(BaseType.isConstQualified() &&
> + BaseType->isIntegralOrEnumerationType()) &&
> + !(VD && VD->getCanonicalDecl() == ED->getCanonicalDecl())) {
> + Info.Diag(E, diag::note_constexpr_access_static_temporary, 1) << AK;
> + Info.Note(MTE->getExprLoc(), diag::note_constexpr_temporary_here);
> + return CompleteObject();
> + }
>
> - BaseVal = &Frame->Temporaries[Base];
> + BaseVal = Info.Ctx.getMaterializedTemporaryValue(MTE, false);
> + assert(BaseVal && "got reference to unevaluated temporary");
> + } else {
> + Info.Diag(E);
> + return CompleteObject();
> + }
> + } else {
> + BaseVal = &Frame->Temporaries[Base];
> + }
>
> // Volatile temporary objects cannot be accessed in constant expressions.
> if (BaseType.isVolatileQualified()) {
> @@ -3940,6 +3980,8 @@ public:
> // * Any Expr, with a CallIndex indicating the function in which the temporary
> // was evaluated, for cases where the MaterializeTemporaryExpr is missing
> // from the AST (FIXME).
> +// * A MaterializeTemporaryExpr that has static storage duration, with no
> +// CallIndex, for a lifetime-extended temporary.
> // plus an offset in bytes.
> //===----------------------------------------------------------------------===//
> namespace {
> @@ -4045,9 +4087,19 @@ bool LValueExprEvaluator::VisitMateriali
> if (!EvaluateIgnoredValue(Info, CommaLHSs[I]))
> return false;
>
> + // A materialized temporary with static storage duration can appear within the
> + // result of a constant expression evaluation, so we need to preserve its
> + // value for use outside this evaluation.
> + APValue *Value;
> + if (E->getStorageDuration() == SD_Static) {
> + Value = Info.Ctx.getMaterializedTemporaryValue(E, true);
> + Result.set(E);
> + } else {
> + Value = &Info.CurrentCall->Temporaries[E];
> + Result.set(E, Info.CurrentCall->Index);
> + }
> +
> // Materialize the temporary itself.
> - APValue *Value = &Info.CurrentCall->Temporaries[E];
> - Result.set(E, Info.CurrentCall->Index);
> if (!EvaluateInPlace(*Value, Info, Result, Inner))
> return false;
>
> @@ -7608,10 +7660,10 @@ void Expr::EvaluateForOverflow(const AST
> }
> }
>
> - bool Expr::EvalResult::isGlobalLValue() const {
> - assert(Val.isLValue());
> - return IsGlobalLValue(Val.getLValueBase());
> - }
> +bool Expr::EvalResult::isGlobalLValue() const {
> + assert(Val.isLValue());
> + return IsGlobalLValue(Val.getLValueBase());
> +}
>
>
> /// isIntegerConstantExpr - this recursive routine will test if an expression is
>
> Modified: cfe/trunk/lib/CodeGen/CGExprConstant.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprConstant.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGExprConstant.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGExprConstant.cpp Tue Jun 4 19:46:14 2013
> @@ -1003,6 +1003,15 @@ public:
> case Expr::CXXUuidofExprClass: {
> return CGM.GetAddrOfUuidDescriptor(cast<CXXUuidofExpr>(E));
> }
> + case Expr::MaterializeTemporaryExprClass: {
> + MaterializeTemporaryExpr *MTE = cast<MaterializeTemporaryExpr>(E);
> + assert(MTE->getStorageDuration() == SD_Static);
> + SmallVector<const Expr *, 2> CommaLHSs;
> + SmallVector<SubobjectAdjustment, 2> Adjustments;
> + const Expr *Inner = MTE->GetTemporaryExpr()
> + ->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
> + return CGM.GetAddrOfGlobalTemporary(MTE, Inner);
> + }
> }
>
> return 0;
>
> Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenModule.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp Tue Jun 4 19:46:14 2013
> @@ -2735,6 +2735,63 @@ llvm::Constant *CodeGenModule::GetAddrOf
> return GetAddrOfConstantString(StrWithNull, GlobalName, Alignment);
> }
>
> +llvm::Constant *CodeGenModule::GetAddrOfGlobalTemporary(
> + const MaterializeTemporaryExpr *E, const Expr *Inner) {
> + assert((E->getStorageDuration() == SD_Static ||
> + E->getStorageDuration() == SD_Thread) && "not a global temporary");
> + const VarDecl *VD = cast<VarDecl>(E->getExtendingDecl());
> +
> + // If we're not materializing a subobject of the temporary, keep the
> + // cv-qualifiers from the type of the MaterializeTemporaryExpr.
> + if (Inner == E->GetTemporaryExpr())
> + Inner = E;
> +
> + llvm::Constant *&Slot = MaterializedGlobalTemporaryMap[E];
> + if (Slot)
> + return Slot;
> +
> + // FIXME: If an externally-visible declaration extends multiple temporaries,
> + // we need to give each temporary the same name in every translation unit (and
> + // we also need to make the temporaries externally-visible).
> + SmallString<256> Name;
> + llvm::raw_svector_ostream Out(Name);
> + getCXXABI().getMangleContext().mangleReferenceTemporary(VD, Out);
> + Out.flush();
> +
> + llvm::Constant *InitialValue = 0;
> + APValue *Value = 0;
> + if (E->getStorageDuration() == SD_Static) {
> + // We might have a constant initializer for this temporary.
> + Value = getContext().getMaterializedTemporaryValue(E, false);
> + if (Value && Value->isUninit())
> + Value = 0;
> + }
> +
> + bool Constant;
> + if (Value) {
> + // The temporary has a constant initializer, use it.
> + InitialValue = EmitConstantValue(*Value, Inner->getType(), 0);
> + Constant = isTypeConstant(Inner->getType(), /*ExcludeCtor*/Value);
> + } else {
> + // No constant initializer, the initialization will be provided when we
> + // initialize the declaration which performed lifetime extension.
> + InitialValue = EmitNullConstant(Inner->getType());
> + Constant = false;
> + }
> +
> + // Create a global variable for this lifetime-extended temporary.
> + llvm::GlobalVariable *GV =
> + new llvm::GlobalVariable(getModule(), InitialValue->getType(), Constant,
> + llvm::GlobalValue::PrivateLinkage, InitialValue,
> + Name.c_str());
> + GV->setAlignment(
> + getContext().getTypeAlignInChars(Inner->getType()).getQuantity());
> + if (VD->getTLSKind())
> + setTLSMode(GV, *VD);
> + Slot = GV;
> + return GV;
> +}
> +
> /// EmitObjCPropertyImplementations - Emit information for synthesized
> /// properties for an implementation.
> void CodeGenModule::EmitObjCPropertyImplementations(const
>
> Modified: cfe/trunk/lib/CodeGen/CodeGenModule.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.h?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenModule.h (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenModule.h Tue Jun 4 19:46:14 2013
> @@ -307,7 +307,8 @@ class CodeGenModule : public CodeGenType
> llvm::StringMap<llvm::GlobalVariable*> ConstantStringMap;
> llvm::DenseMap<const Decl*, llvm::Constant *> StaticLocalDeclMap;
> llvm::DenseMap<const Decl*, llvm::GlobalVariable*> StaticLocalDeclGuardMap;
> -
> + llvm::DenseMap<const Expr*, llvm::Constant *> MaterializedGlobalTemporaryMap;
> +
> llvm::DenseMap<QualType, llvm::Constant *> AtomicSetterHelperFnMap;
> llvm::DenseMap<QualType, llvm::Constant *> AtomicGetterHelperFnMap;
>
> @@ -731,7 +732,12 @@ public:
> /// GetAddrOfConstantCompoundLiteral - Returns a pointer to a constant global
> /// variable for the given file-scope compound literal expression.
> llvm::Constant *GetAddrOfConstantCompoundLiteral(const CompoundLiteralExpr*E);
> -
> +
> + /// \brief Returns a pointer to a global variable representing a temporary
> + /// with static or thread storage duration.
> + llvm::Constant *GetAddrOfGlobalTemporary(const MaterializeTemporaryExpr *E,
> + const Expr *Inner);
> +
> /// \brief Retrieve the record type that describes the state of an
> /// Objective-C fast enumeration loop (for..in).
> QualType getObjCFastEnumerationStateType();
>
> Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaExpr.cpp Tue Jun 4 19:46:14 2013
> @@ -8353,7 +8353,7 @@ static QualType CheckAddressOfOperand(Se
> return QualType();
> // Materialize the temporary as an lvalue so that we can take its address.
> OrigOp = op = new (S.Context)
> - MaterializeTemporaryExpr(op->getType(), OrigOp.take(), true);
> + MaterializeTemporaryExpr(op->getType(), OrigOp.take(), true, 0);
> } else if (isa<ObjCSelectorExpr>(op)) {
> return S.Context.getPointerType(op->getType());
> } else if (lval == Expr::LV_MemberFunction) {
>
> Modified: cfe/trunk/lib/Sema/SemaInit.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaInit.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaInit.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaInit.cpp Tue Jun 4 19:46:14 2013
> @@ -2502,6 +2502,46 @@ bool InitializedEntity::allowsNRVO() con
> return false;
> }
>
> +unsigned InitializedEntity::dumpImpl(raw_ostream &OS) const {
> + unsigned Depth = getParent() ? getParent()->dumpImpl(OS) : 0;
> + for (unsigned I = 0; I != Depth; ++I)
> + OS << "`-";
> +
> + switch (getKind()) {
> + case EK_Variable: OS << "Variable"; break;
> + case EK_Parameter: OS << "Parameter"; break;
> + case EK_Result: OS << "Result"; break;
> + case EK_Exception: OS << "Exception"; break;
> + case EK_Member: OS << "Member"; break;
> + case EK_New: OS << "New"; break;
> + case EK_Temporary: OS << "Temporary"; break;
> + case EK_CompoundLiteralInit: OS << "CompoundLiteral";break;
> + case EK_Base: OS << "Base"; break;
> + case EK_Delegating: OS << "Delegating"; break;
> + case EK_ArrayElement: OS << "ArrayElement " << Index; break;
> + case EK_VectorElement: OS << "VectorElement " << Index; break;
> + case EK_ComplexElement: OS << "ComplexElement " << Index; break;
> + case EK_BlockElement: OS << "Block"; break;
> + case EK_LambdaCapture:
> + OS << "LambdaCapture ";
> + getCapturedVar()->printName(OS);
> + break;
> + }
> +
> + if (Decl *D = getDecl()) {
> + OS << " ";
> + cast<NamedDecl>(D)->printQualifiedName(OS);
> + }
> +
> + OS << " '" << getType().getAsString() << "'\n";
> +
> + return Depth + 1;
> +}
> +
> +void InitializedEntity::dump() const {
> + dumpImpl(llvm::errs());
> +}
> +
> //===----------------------------------------------------------------------===//
> // Initialization sequence
> //===----------------------------------------------------------------------===//
> @@ -5089,6 +5129,143 @@ InitializedEntityOutlivesFullExpression(
> llvm_unreachable("unknown entity kind");
> }
>
> +/// Determine the declaration which an initialized entity ultimately refers to,
> +/// for the purpose of lifetime-extending a temporary bound to a reference in
> +/// the initialization of \p Entity.
> +static const ValueDecl *
> +getDeclForTemporaryLifetimeExtension(const InitializedEntity &Entity,
> + const ValueDecl *FallbackDecl = 0) {
> + // C++11 [class.temporary]p5:
> + switch (Entity.getKind()) {
> + case InitializedEntity::EK_Variable:
> + // The temporary [...] persists for the lifetime of the reference
> + return Entity.getDecl();
> +
> + case InitializedEntity::EK_Member:
> + // For subobjects, we look at the complete object.
> + if (Entity.getParent())
> + return getDeclForTemporaryLifetimeExtension(*Entity.getParent(),
> + Entity.getDecl());
> +
> + // except:
> + // -- A temporary bound to a reference member in a constructor's
> + // ctor-initializer persists until the constructor exits.
> + return Entity.getDecl();
> +
> + case InitializedEntity::EK_Parameter:
> + // -- A temporary bound to a reference parameter in a function call
> + // persists until the completion of the full-expression containing
> + // the call.
> + case InitializedEntity::EK_Result:
> + // -- The lifetime of a temporary bound to the returned value in a
> + // function return statement is not extended; the temporary is
> + // destroyed at the end of the full-expression in the return statement.
> + case InitializedEntity::EK_New:
> + // -- A temporary bound to a reference in a new-initializer persists
> + // until the completion of the full-expression containing the
> + // new-initializer.
> + return 0;
> +
> + case InitializedEntity::EK_Temporary:
> + case InitializedEntity::EK_CompoundLiteralInit:
> + // We don't yet know the storage duration of the surrounding temporary.
> + // Assume it's got full-expression duration for now, it will patch up our
> + // storage duration if that's not correct.
> + return 0;
> +
> + case InitializedEntity::EK_ArrayElement:
> + // For subobjects, we look at the complete object.
> + return getDeclForTemporaryLifetimeExtension(*Entity.getParent(),
> + FallbackDecl);
> +
> + case InitializedEntity::EK_Base:
> + case InitializedEntity::EK_Delegating:
> + // We can reach this case for aggregate initialization in a constructor:
> + // struct A { int &&r; };
> + // struct B : A { B() : A{0} {} };
> + // In this case, use the innermost field decl as the context.
> + return FallbackDecl;
> +
> + case InitializedEntity::EK_BlockElement:
> + case InitializedEntity::EK_LambdaCapture:
> + case InitializedEntity::EK_Exception:
> + case InitializedEntity::EK_VectorElement:
> + case InitializedEntity::EK_ComplexElement:
> + llvm_unreachable("should not materialize a temporary to initialize this");
> + }
> +}
> +
> +static void performLifetimeExtension(Expr *Init, const ValueDecl *ExtendingD);
> +
> +/// Update a glvalue expression that is used as the initializer of a reference
> +/// to note that its lifetime is extended.
> +static void performReferenceExtension(Expr *Init, const ValueDecl *ExtendingD) {
> + if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
> + if (ILE->getNumInits() == 1 && ILE->isGLValue()) {
> + // This is just redundant braces around an initializer. Step over it.
> + Init = ILE->getInit(0);
> + }
> + }
> +
> + if (MaterializeTemporaryExpr *ME = dyn_cast<MaterializeTemporaryExpr>(Init)) {
> + // Update the storage duration of the materialized temporary.
> + // FIXME: Rebuild the expression instead of mutating it.
> + ME->setExtendingDecl(ExtendingD);
> + performLifetimeExtension(ME->GetTemporaryExpr(), ExtendingD);
> + }
> +}
> +
> +/// Update a prvalue expression that is going to be materialized as a
> +/// lifetime-extended temporary.
> +static void performLifetimeExtension(Expr *Init, const ValueDecl *ExtendingD) {
> + // Dig out the expression which constructs the extended temporary.
> + SmallVector<const Expr *, 2> CommaLHSs;
> + SmallVector<SubobjectAdjustment, 2> Adjustments;
> + Init = const_cast<Expr *>(
> + Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments));
> +
> + if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
> + if (ILE->initializesStdInitializerList()) {
> + // FIXME: If this is an InitListExpr which creates a std::initializer_list
> + // object, we also need to lifetime-extend the underlying array
> + // itself. Fix the representation to explicitly materialize an
> + // array temporary so we can model this properly.
> + for (unsigned I = 0, N = ILE->getNumInits(); I != N; ++I)
> + performLifetimeExtension(ILE->getInit(I), ExtendingD);
> + return;
> + }
> +
> + CXXRecordDecl *RD = Init->getType()->getAsCXXRecordDecl();
> + if (RD) {
> + assert(RD->isAggregate() && "aggregate init on non-aggregate");
> +
> + // If we lifetime-extend a braced initializer which is initializing an
> + // aggregate, and that aggregate contains reference members which are
> + // bound to temporaries, those temporaries are also lifetime-extended.
> + if (RD->isUnion() && ILE->getInitializedFieldInUnion() &&
> + ILE->getInitializedFieldInUnion()->getType()->isReferenceType())
> + performReferenceExtension(ILE->getInit(0), ExtendingD);
> + else {
> + unsigned Index = 0;
> + for (RecordDecl::field_iterator I = RD->field_begin(),
> + E = RD->field_end();
> + I != E; ++I) {
> + if (I->isUnnamedBitfield())
> + continue;
> + if (I->getType()->isReferenceType())
> + performReferenceExtension(ILE->getInit(Index), ExtendingD);
> + else if (isa<InitListExpr>(ILE->getInit(Index)))
> + // This may be either aggregate-initialization of a member or
> + // initialization of a std::initializer_list object. Either way,
> + // we should recursively lifetime-extend that initializer.
> + performLifetimeExtension(ILE->getInit(Index), ExtendingD);
> + ++Index;
> + }
> + }
> + }
> + }
> +}
> +
> ExprResult
> InitializationSequence::Perform(Sema &S,
> const InitializedEntity &Entity,
> @@ -5326,7 +5503,7 @@ InitializationSequence::Perform(Sema &S,
>
> break;
>
> - case SK_BindReferenceToTemporary:
> + case SK_BindReferenceToTemporary: {
> // Make sure the "temporary" is actually an rvalue.
> assert(CurInit.get()->isRValue() && "not a temporary");
>
> @@ -5334,11 +5511,17 @@ InitializationSequence::Perform(Sema &S,
> if (S.CheckExceptionSpecCompatibility(CurInit.get(), DestType))
> return ExprError();
>
> + // Maybe lifetime-extend the temporary's subobjects to match the
> + // entity's lifetime.
> + const ValueDecl *ExtendingDecl =
> + getDeclForTemporaryLifetimeExtension(Entity);
> + if (ExtendingDecl)
> + performLifetimeExtension(CurInit.get(), ExtendingDecl);
> +
> // Materialize the temporary into memory.
> CurInit = new (S.Context) MaterializeTemporaryExpr(
> - Entity.getType().getNonReferenceType(),
> - CurInit.get(),
> - Entity.getType()->isLValueReferenceType());
> + Entity.getType().getNonReferenceType(), CurInit.get(),
> + Entity.getType()->isLValueReferenceType(), ExtendingDecl);
>
> // If we're binding to an Objective-C object that has lifetime, we
> // need cleanups.
> @@ -5347,6 +5530,7 @@ InitializationSequence::Perform(Sema &S,
> S.ExprNeedsCleanups = true;
>
> break;
> + }
>
> case SK_ExtraneousCopyToTemporary:
> CurInit = CopyObject(S, Step->Type, Entity, CurInit,
>
> Modified: cfe/trunk/lib/Serialization/ASTReaderStmt.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderStmt.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Serialization/ASTReaderStmt.cpp (original)
> +++ cfe/trunk/lib/Serialization/ASTReaderStmt.cpp Tue Jun 4 19:46:14 2013
> @@ -1576,6 +1576,7 @@ void ASTStmtReader::VisitFunctionParmPac
> void ASTStmtReader::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E) {
> VisitExpr(E);
> E->Temporary = Reader.ReadSubExpr();
> + E->ExtendingDecl = ReadDeclAs<ValueDecl>(Record, Idx);
> }
>
> void ASTStmtReader::VisitOpaqueValueExpr(OpaqueValueExpr *E) {
>
> Modified: cfe/trunk/lib/Serialization/ASTWriterStmt.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriterStmt.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Serialization/ASTWriterStmt.cpp (original)
> +++ cfe/trunk/lib/Serialization/ASTWriterStmt.cpp Tue Jun 4 19:46:14 2013
> @@ -1572,6 +1572,7 @@ void ASTStmtWriter::VisitFunctionParmPac
> void ASTStmtWriter::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr *E) {
> VisitExpr(E);
> Writer.AddStmt(E->Temporary);
> + Writer.AddDeclRef(E->ExtendingDecl, Record);
> Code = serialization::EXPR_MATERIALIZE_TEMPORARY;
> }
>
>
> Modified: cfe/trunk/test/CodeGenCXX/const-init-cxx11.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/const-init-cxx11.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/const-init-cxx11.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/const-init-cxx11.cpp Tue Jun 4 19:46:14 2013
> @@ -224,12 +224,50 @@ namespace LiteralReference {
> constexpr Lit() : n(5) {}
> int n;
> };
> - // FIXME: This should have static initialization, but we do not implement
> - // that yet. For now, just check that we don't set the (pointer) value of
> - // the reference to 5!
> - //
> - // CHECK: @_ZN16LiteralReference3litE = global {{.*}} null
> +
> + // This creates a non-const temporary and binds a reference to it.
> + // CHECK: @[[TEMP:.*]] = private global {{.*}} { i32 5 }, align 4
> + // CHECK: @_ZN16LiteralReference3litE = constant {{.*}} @[[TEMP]], align 8
> const Lit &lit = Lit();
> +
> + // This creates a const temporary as part of the reference initialization.
> + // CHECK: @[[TEMP:.*]] = private constant {{.*}} { i32 5 }, align 4
> + // CHECK: @_ZN16LiteralReference4lit2E = constant {{.*}} @[[TEMP]], align 8
> + const Lit &lit2 = {};
> +
> + struct A { int &&r1; const int &&r2; };
> + struct B { A &&a1; const A &&a2; };
> + B b = { { 0, 1 }, { 2, 3 } };
> + // CHECK: @[[TEMP0:.*]] = private global i32 0, align 4
> + // CHECK: @[[TEMP1:.*]] = private constant i32 1, align 4
> + // CHECK: @[[TEMPA1:.*]] = private global {{.*}} { i32* @[[TEMP0]], i32* @[[TEMP1]] }, align 8
> + // CHECK: @[[TEMP2:.*]] = private global i32 2, align 4
> + // CHECK: @[[TEMP3:.*]] = private constant i32 3, align 4
> + // CHECK: @[[TEMPA2:.*]] = private constant {{.*}} { i32* @[[TEMP2]], i32* @[[TEMP3]] }, align 8
> + // CHECK: @_ZN16LiteralReference1bE = global {{.*}} { {{.*}}* @[[TEMPA1]], {{.*}}* @[[TEMPA2]] }, align 8
> +
> + struct Subobj {
> + int a, b, c;
> + };
> + // CHECK: @[[TEMP:.*]] = private global {{.*}} { i32 1, i32 2, i32 3 }, align 4
> + // CHECK: @_ZN16LiteralReference2soE = constant {{.*}} (i8* getelementptr {{.*}} @[[TEMP]]{{.*}}, i64 4)
> + constexpr int &&so = Subobj{ 1, 2, 3 }.b;
> +
> + struct Dummy { int padding; };
> + struct Derived : Dummy, Subobj {
> + constexpr Derived() : Dummy{200}, Subobj{4, 5, 6} {}
> + };
> + using ConstDerived = const Derived;
> + // CHECK: @[[TEMPCOMMA:.*]] = private constant {{.*}} { i32 200, i32 4, i32 5, i32 6 }
> + // CHECK: @_ZN16LiteralReference5commaE = constant {{.*}} getelementptr {{.*}} @[[TEMPCOMMA]]{{.*}}, i64 8)
> + constexpr const int &comma = (1, (2, ConstDerived{}).b);
> +
> + // CHECK: @[[TEMPDERIVED:.*]] = private global {{.*}} { i32 200, i32 4, i32 5, i32 6 }
> + // CHECK: @_ZN16LiteralReference4baseE = constant {{.*}} getelementptr {{.*}} @[[TEMPDERIVED]]{{.*}}, i64 4)
> + constexpr Subobj &&base = Derived{};
> +
> + // CHECK: @_ZN16LiteralReference7derivedE = constant {{.*}} @[[TEMPDERIVED]]
> + constexpr Derived &derived = static_cast<Derived&>(base);
> }
>
> namespace NonLiteralConstexpr {
> @@ -330,6 +368,17 @@ namespace PR13273 {
> extern const S s {};
> }
>
> +namespace UnemittedTemporaryDecl {
> + constexpr int &&ref = 0;
> + extern constexpr int &ref2 = ref;
> + // CHECK: @_ZGRN22UnemittedTemporaryDecl3refE = private global i32 0
> +
> + // FIXME: This declaration should not be emitted -- it isn't odr-used.
> + // CHECK: @_ZN22UnemittedTemporaryDecl3refE
> +
> + // CHECK: @_ZN22UnemittedTemporaryDecl4ref2E = constant i32* @_ZGRN22UnemittedTemporaryDecl3refE
> +}
> +
> // CHECK: @_ZZN12LocalVarInit3aggEvE1a = internal constant {{.*}} i32 101
> // CHECK: @_ZZN12LocalVarInit4ctorEvE1a = internal constant {{.*}} i32 102
> // CHECK: @_ZZN12LocalVarInit8mutable_EvE1a = private unnamed_addr constant {{.*}} i32 103
>
> Modified: cfe/trunk/test/CodeGenCXX/const-init-cxx1y.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/const-init-cxx1y.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/const-init-cxx1y.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/const-init-cxx1y.cpp Tue Jun 4 19:46:14 2013
> @@ -17,4 +17,13 @@ B b;
>
> // CHECK: @b = global {{.*}} i32 1, {{.*}} { i32 2 }, {{.*}} { i32 3 }, {{.*}} { i32 4 }
> // CHECK-NOT: _ZN1BC
> -// CHECK: __cxa_atexit
> +
> +namespace ModifyStaticTemporary {
> + struct A { int &&temporary; int x; };
> + constexpr int f(int &r) { r *= 9; return r - 12; }
> + A a = { 6, f(a.temporary) };
> + // CHECK: @_ZGRN21ModifyStaticTemporary1aE = private global i32 54
> + // CHECK: @_ZN21ModifyStaticTemporary1aE = global {{.*}} i32* @_ZGRN21ModifyStaticTemporary1aE, i32 42
> +}
> +
> +// CHECK: __cxa_atexit({{.*}} @_ZN1BD1Ev {{.*}} @b
>
> Modified: cfe/trunk/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/cxx0x-initializer-stdinitializerlist.cpp Tue Jun 4 19:46:14 2013
> @@ -284,4 +284,7 @@ namespace dtors {
> void f() {
> std::initializer_list<S>{ S(), S() };
> }
> + void g() {
> + auto x = std::initializer_list<S>{ S(), S() };
> + }
> }
>
> Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp (original)
> +++ cfe/trunk/test/SemaCXX/constant-expression-cxx11.cpp Tue Jun 4 19:46:14 2013
> @@ -339,6 +339,30 @@ static_assert(!same(4, 4), "");
> static_assert(same(n, n), "");
> static_assert(sameTemporary(9), "");
>
> +struct A { int &&r; };
> +struct B { A &&a1; A &&a2; };
> +
> +constexpr B b1 { { 1 }, { 2 } }; // expected-note {{temporary created here}}
> +static_assert(&b1.a1 != &b1.a2, "");
> +static_assert(&b1.a1.r != &b1.a2.r, ""); // expected-error {{constant expression}} expected-note {{outside the expression that created the temporary}}
> +
> +constexpr B &&b2 { { 3 }, { 4 } }; // expected-note {{temporary created here}}
> +static_assert(&b1 != &b2, "");
> +static_assert(&b1.a1 != &b2.a1, ""); // expected-error {{constant expression}} expected-note {{outside the expression that created the temporary}}
> +
> +constexpr thread_local B b3 { { 1 }, { 2 } }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}
> +void foo() {
> + constexpr static B b1 { { 1 }, { 2 } }; // ok
> + constexpr thread_local B b2 { { 1 }, { 2 } }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}
> + constexpr B b3 { { 1 }, { 2 } }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}
> +}
> +
> +constexpr B &&b4 = ((1, 2), 3, 4, B { {10}, {{20}} }); // expected-warning 4{{unused}}
> +static_assert(&b4 != &b2, "");
> +
> +// Proposed DR: copy-elision doesn't trigger lifetime extension.
> +constexpr B b5 = B{ {0}, {0} }; // expected-error {{constant expression}} expected-note {{reference to temporary}} expected-note {{here}}
> +
> }
>
> constexpr int strcmp_ce(const char *p, const char *q) {
> @@ -572,7 +596,7 @@ struct E {
> constexpr E() : p(&p) {}
> void *p;
> };
> -constexpr const E &e1 = E(); // expected-error {{constant expression}} expected-note {{reference to temporary is not a constant expression}} expected-note {{temporary created here}}
> +constexpr const E &e1 = E();
> // This is a constant expression if we elide the copy constructor call, and
> // is not a constant expression if we don't! But we do, so it is.
> constexpr E e2 = E();
> @@ -1282,8 +1306,23 @@ struct Wrap {
> constexpr const Wrap &g(const Wrap &w) { return w; }
> constexpr int k2 = g({0}).value; // ok
>
> -constexpr const int &i = 0; // expected-error {{constant expression}} expected-note {{temporary}} expected-note 2{{here}}
> -constexpr const int j = i; // expected-error {{constant expression}} expected-note {{initializer of 'i' is not a constant expression}}
> +// The temporary here has static storage duration, so we can bind a constexpr
> +// reference to it.
> +constexpr const int &i = 1;
> +constexpr const int j = i;
> +static_assert(j == 1, "");
> +
> +// The temporary here is not const, so it can't be read outside the expression
> +// in which it was created (per the C++14 rules, which we use to avoid a C++11
> +// defect).
> +constexpr int &&k = 1; // expected-note {{temporary created here}}
> +constexpr const int l = k; // expected-error {{constant expression}} expected-note {{read of temporary}}
> +
> +void f() {
> + // The temporary here has automatic storage duration, so we can't bind a
> + // constexpr reference to it.
> + constexpr const int &i = 1; // expected-error {{constant expression}} expected-note 2{{temporary}}
> +}
>
> }
>
>
> Modified: cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp?rev=183283&r1=183282&r2=183283&view=diff
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp (original)
> +++ cfe/trunk/test/SemaCXX/constant-expression-cxx1y.cpp Tue Jun 4 19:46:14 2013
> @@ -715,3 +715,13 @@ namespace deduced_return_type {
> static_assert(f() == 0, "");
> static_assert(g(true), "");
> }
> +
> +namespace modify_temporary_during_construction {
> + struct A { int &&temporary; int x; int y; };
> + constexpr int f(int &r) { r *= 9; return r - 12; }
> + // FIXME: The 'uninitialized' warning here is bogus.
> + constexpr A a = { 6, f(a.temporary), a.temporary }; // expected-warning {{uninitialized}} expected-note {{temporary created here}}
> + static_assert(a.x == 42, "");
> + static_assert(a.y == 54, "");
> + constexpr int k = a.temporary++; // expected-error {{constant expression}} expected-note {{outside the expression that created the temporary}}
> +}
>
>
> _______________________________________________
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