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.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183283 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index f5c8187..ca331cc 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -1003,6 +1003,15 @@
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;
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 3675e84..4d64624 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -2735,6 +2735,63 @@
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
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index 2777f95..aa48cce 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -307,7 +307,8 @@
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 @@
/// 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();