/// 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 LifetimeResult getEntityLifetime(
+static LifetimeResult getEntityForTemporaryLifetimeExtension(
const InitializedEntity *Entity,
const InitializedEntity *InitField = nullptr) {
// C++11 [class.temporary]p5:
case InitializedEntity::EK_Member:
// For subobjects, we look at the complete object.
if (Entity->getParent())
- return getEntityLifetime(Entity->getParent(), Entity);
+ return getEntityForTemporaryLifetimeExtension(Entity->getParent(),
+ Entity);
// except:
// C++17 [class.base.init]p8:
case InitializedEntity::EK_ArrayElement:
// For subobjects, we look at the complete object.
- return getEntityLifetime(Entity->getParent(), InitField);
+ return getEntityForTemporaryLifetimeExtension(Entity->getParent(),
+ InitField);
case InitializedEntity::EK_Base:
// For subobjects, we look at the complete object.
if (Entity->getParent())
- return getEntityLifetime(Entity->getParent(), InitField);
+ return getEntityForTemporaryLifetimeExtension(Entity->getParent(),
+ InitField);
return {InitField, LK_MemInitializer};
case InitializedEntity::EK_Delegating:
case InitializedEntity::EK_BlockElement:
case InitializedEntity::EK_LambdaToBlockConversionBlockElement:
case InitializedEntity::EK_LambdaCapture:
+ case InitializedEntity::EK_Exception:
case InitializedEntity::EK_VectorElement:
case InitializedEntity::EK_ComplexElement:
return {nullptr, LK_FullExpression};
-
- case InitializedEntity::EK_Exception:
- // FIXME: Can we diagnose lifetime problems with exceptions?
- return {nullptr, LK_FullExpression};
}
llvm_unreachable("unknown entity kind");
}
namespace {
-enum ReferenceKind {
+enum ExtensionKind {
/// Lifetime would be extended by a reference binding to a temporary.
- RK_ReferenceBinding,
+ EK_ReferenceBinding,
/// Lifetime would be extended by a std::initializer_list object binding to
/// its backing array.
- RK_StdInitializerList,
-};
-
-/// A temporary or local variable.
-using Local = llvm::PointerUnion<MaterializeTemporaryExpr*, ValueDecl*>;
-
-/// Expressions we stepped over when looking for the local state. Any steps
-/// that would inhibit lifetime extension or take us out of subexpressions of
-/// the initializer are included.
-struct IndirectLocalPathEntry {
- enum {
- DefaultInit,
- AddressOf,
- } Kind;
- Expr *E;
+ EK_StdInitializerList,
};
-
-using IndirectLocalPath = llvm::SmallVectorImpl<IndirectLocalPathEntry>;
+using IndirectTemporaryPathEntry =
+ llvm::PointerUnion<CXXDefaultInitExpr *, ValueDecl *>;
+using IndirectTemporaryPath = llvm::SmallVectorImpl<IndirectTemporaryPathEntry>;
struct RevertToOldSizeRAII {
- IndirectLocalPath &Path;
+ IndirectTemporaryPath &Path;
unsigned OldSize = Path.size();
- RevertToOldSizeRAII(IndirectLocalPath &Path) : Path(Path) {}
+ RevertToOldSizeRAII(IndirectTemporaryPath &Path) : Path(Path) {}
~RevertToOldSizeRAII() { Path.resize(OldSize); }
};
}
-template <typename LocalVisitor>
-static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
- Expr *Init, LocalVisitor Visit,
- bool RevisitSubinits);
+template <typename TemporaryVisitor>
+static void visitTemporariesExtendedByInitializer(IndirectTemporaryPath &Path,
+ Expr *Init,
+ TemporaryVisitor Visit);
-/// Visit the locals that would be reachable through a reference bound to the
-/// glvalue expression \c Init.
-template <typename LocalVisitor>
-static void visitLocalsRetainedByReferenceBinding(IndirectLocalPath &Path,
- Expr *Init, ReferenceKind RK,
- LocalVisitor Visit) {
+/// Visit the temporaries whose lifetimes would be extended by binding a
+/// reference to the glvalue expression \c Init.
+template <typename TemporaryVisitor>
+static void
+visitTemporariesExtendedByReferenceBinding(IndirectTemporaryPath &Path,
+ Expr *Init, ExtensionKind EK,
+ TemporaryVisitor Visit) {
RevertToOldSizeRAII RAII(Path);
// Walk past any constructs which we can lifetime-extend across.
// Step into CXXDefaultInitExprs so we can diagnose cases where a
// constructor inherits one as an implicit mem-initializer.
if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
- Path.push_back({IndirectLocalPathEntry::DefaultInit, DIE});
+ Path.push_back(DIE);
Init = DIE->getExpr();
if (auto *EWC = dyn_cast<ExprWithCleanups>(Init))
} while (Init != Old);
if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(Init)) {
- if (Visit(Path, Local(MTE), RK))
- visitLocalsRetainedByInitializer(Path, MTE->GetTemporaryExpr(), Visit,
- true);
- }
-
- // If we find the name of a local non-reference parameter, we could have a
- // lifetime problem.
- if (auto *DRE = dyn_cast<DeclRefExpr>(Init->IgnoreParens())) {
- auto *VD = dyn_cast<VarDecl>(DRE->getDecl());
- if (VD && VD->hasLocalStorage() &&
- !DRE->refersToEnclosingVariableOrCapture()) {
- // FIXME: Recurse to the initializer of a local reference.
- if (!VD->getType()->isReferenceType())
- Visit(Path, Local(VD), RK);
- }
+ if (Visit(Path, MTE, EK))
+ visitTemporariesExtendedByInitializer(Path, MTE->GetTemporaryExpr(),
+ Visit);
}
}
-/// Visit the locals that would be reachable through an object initialized by
-/// the prvalue expression \c Init.
-template <typename LocalVisitor>
-static void visitLocalsRetainedByInitializer(IndirectLocalPath &Path,
- Expr *Init, LocalVisitor Visit,
- bool RevisitSubinits) {
+/// Visit the temporaries whose lifetimes would be extended by
+/// lifetime-extending the object initialized by the prvalue expression \c
+/// Init.
+template <typename TemporaryVisitor>
+static void visitTemporariesExtendedByInitializer(IndirectTemporaryPath &Path,
+ Expr *Init,
+ TemporaryVisitor Visit) {
RevertToOldSizeRAII RAII(Path);
// Step into CXXDefaultInitExprs so we can diagnose cases where a
// constructor inherits one as an implicit mem-initializer.
if (auto *DIE = dyn_cast<CXXDefaultInitExpr>(Init)) {
- Path.push_back({IndirectLocalPathEntry::DefaultInit, DIE});
+ Path.push_back(DIE);
Init = DIE->getExpr();
if (auto *EWC = dyn_cast<ExprWithCleanups>(Init))
// initializing an initializer_list object from the array extends the
// lifetime of the array exactly like binding a reference to a temporary.
if (auto *ILE = dyn_cast<CXXStdInitializerListExpr>(Init))
- return visitLocalsRetainedByReferenceBinding(Path, ILE->getSubExpr(),
- RK_StdInitializerList, Visit);
+ return visitTemporariesExtendedByReferenceBinding(
+ Path, ILE->getSubExpr(), EK_StdInitializerList, Visit);
if (InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
- // We already visited the elements of this initializer list while
- // performing the initialization. Don't visit them again unless we've
- // changed the lifetime of the initialized entity.
- if (!RevisitSubinits)
- return;
-
if (ILE->isTransparent())
- return visitLocalsRetainedByInitializer(Path, ILE->getInit(0), Visit,
- RevisitSubinits);
+ return visitTemporariesExtendedByInitializer(Path, ILE->getInit(0),
+ Visit);
if (ILE->getType()->isArrayType()) {
for (unsigned I = 0, N = ILE->getNumInits(); I != N; ++I)
- visitLocalsRetainedByInitializer(Path, ILE->getInit(I), Visit,
- RevisitSubinits);
+ visitTemporariesExtendedByInitializer(Path, ILE->getInit(I), Visit);
return;
}
// bound to temporaries, those temporaries are also lifetime-extended.
if (RD->isUnion() && ILE->getInitializedFieldInUnion() &&
ILE->getInitializedFieldInUnion()->getType()->isReferenceType())
- visitLocalsRetainedByReferenceBinding(Path, ILE->getInit(0),
- RK_ReferenceBinding, Visit);
+ visitTemporariesExtendedByReferenceBinding(Path, ILE->getInit(0),
+ EK_ReferenceBinding, Visit);
else {
unsigned Index = 0;
for (const auto *I : RD->fields()) {
continue;
Expr *SubInit = ILE->getInit(Index);
if (I->getType()->isReferenceType())
- visitLocalsRetainedByReferenceBinding(Path, SubInit,
- RK_ReferenceBinding, Visit);
+ visitTemporariesExtendedByReferenceBinding(
+ Path, SubInit, EK_ReferenceBinding, Visit);
else
// This might be either aggregate-initialization of a member or
// initialization of a std::initializer_list object. Regardless,
// we should recursively lifetime-extend that initializer.
- visitLocalsRetainedByInitializer(Path, SubInit, Visit,
- RevisitSubinits);
+ visitTemporariesExtendedByInitializer(Path, SubInit, Visit);
++Index;
}
}
}
- return;
- }
-
- // If the initializer is the address of a local, we could have a lifetime
- // problem.
- if (auto *Op = dyn_cast<UnaryOperator>(Init->IgnoreParenImpCasts())) {
- if (Op->getOpcode() == UO_AddrOf) {
- Path.push_back({IndirectLocalPathEntry::AddressOf, Op});
- Init = Op->getSubExpr();
- return visitLocalsRetainedByReferenceBinding(Path, Init,
- RK_ReferenceBinding, Visit);
- }
}
}
/// Determine whether this is an indirect path to a temporary that we are
/// supposed to lifetime-extend along (but don't).
-static bool shouldLifetimeExtendThroughPath(const IndirectLocalPath &Path) {
+static bool shouldLifetimeExtendThroughPath(const IndirectTemporaryPath &Path) {
for (auto Elem : Path) {
- if (Elem.Kind != IndirectLocalPathEntry::DefaultInit)
+ if (!Elem.is<CXXDefaultInitExpr*>())
return false;
}
return true;
void Sema::checkInitializerLifetime(const InitializedEntity &Entity,
Expr *Init) {
- LifetimeResult LR = getEntityLifetime(&Entity);
+ LifetimeResult LR = getEntityForTemporaryLifetimeExtension(&Entity);
LifetimeKind LK = LR.getInt();
const InitializedEntity *ExtendingEntity = LR.getPointer();
if (LK == LK_FullExpression)
return;
- auto TemporaryVisitor = [&](IndirectLocalPath &Path, Local L,
- ReferenceKind RK) -> bool {
- // If we found a path to a local variable or similar, check whether the
- // initialized object will outlive it.
- if (auto *VD = L.dyn_cast<ValueDecl*>()) {
- switch (LK) {
- case LK_FullExpression:
- llvm_unreachable("already handled this");
-
- case LK_Extended:
- break;
-
- case LK_MemInitializer: {
- // Paths via a default initializer can only occur during error recovery
- // (there's no other way that a default initializer can refer to a
- // local). Don't produce a bogus warning on those cases.
- if (std::any_of(Path.begin(), Path.end(), [](IndirectLocalPathEntry E) {
- return E.Kind == IndirectLocalPathEntry::DefaultInit;
- }))
- break;
-
- if (auto *Member =
- ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
- bool AddressTaken =
- !Path.empty() &&
- Path.back().Kind == IndirectLocalPathEntry::AddressOf;
- Diag(Init->getExprLoc(),
- AddressTaken ? diag::warn_init_ptr_member_to_parameter_addr
- : diag::warn_bind_ref_member_to_parameter)
- << Member << VD << isa<ParmVarDecl>(VD) << Init->getSourceRange();
- Diag(Member->getLocation(),
- diag::note_ref_or_ptr_member_declared_here)
- << (unsigned)AddressTaken;
- }
- break;
- }
-
- case LK_New:
- break;
-
- case LK_Return:
- // FIXME: Move -Wreturn-stack-address checks here.
- return false;
- }
- return false;
- }
-
- auto *MTE = L.get<MaterializeTemporaryExpr*>();
+ auto TemporaryVisitor = [&](IndirectTemporaryPath &Path,
+ MaterializeTemporaryExpr *MTE,
+ ExtensionKind EK) -> bool {
switch (LK) {
case LK_FullExpression:
llvm_unreachable("already handled this");
// would be to clone the initializer expression on each use that would
// lifetime extend its temporaries.
Diag(MTE->getExprLoc(),
- RK == RK_ReferenceBinding
+ EK == EK_ReferenceBinding
? diag::warn_default_member_init_temporary_not_extended
: diag::warn_default_member_init_init_list_not_extended);
} else {
- // FIXME: Warn on this.
+ llvm_unreachable("unexpected indirect temporary path");
}
break;
// Under C++ DR1696, if a mem-initializer (or a default member
// initializer used by the absence of one) would lifetime-extend a
// temporary, the program is ill-formed.
- if (auto *ExtendingDecl =
- ExtendingEntity ? ExtendingEntity->getDecl() : nullptr) {
+ if (auto *ExtendingDecl = ExtendingEntity->getDecl()) {
bool IsSubobjectMember = ExtendingEntity != &Entity;
Diag(MTE->getExprLoc(), diag::err_bind_ref_member_to_temporary)
<< ExtendingDecl << Init->getSourceRange() << IsSubobjectMember
- << RK;
+ << EK;
// Don't bother adding a note pointing to the field if we're inside its
// default member initializer; our primary diagnostic points to the
// same place in that case.
- if (Path.empty() ||
- Path.back().Kind != IndirectLocalPathEntry::DefaultInit) {
+ if (Path.empty() || !Path.back().is<CXXDefaultInitExpr*>()) {
Diag(ExtendingDecl->getLocation(),
diag::note_lifetime_extending_member_declared_here)
- << RK << IsSubobjectMember;
+ << EK << IsSubobjectMember;
}
} else {
// We have a mem-initializer but no particular field within it; this
break;
case LK_New:
- if (RK == RK_ReferenceBinding) {
+ if (EK == EK_ReferenceBinding) {
Diag(MTE->getExprLoc(), diag::warn_new_dangling_reference);
} else {
Diag(MTE->getExprLoc(), diag::warn_new_dangling_initializer_list)
// FIXME: Model these as CodeSynthesisContexts to fix the note emission
// order.
for (auto Elem : llvm::reverse(Path)) {
- switch (Elem.Kind) {
- case IndirectLocalPathEntry::DefaultInit:
- Diag(Elem.E->getExprLoc(), diag::note_in_default_member_initalizer_here)
- << cast<CXXDefaultInitExpr>(Elem.E)->getField();
- break;
-
- case IndirectLocalPathEntry::AddressOf:
- break;
+ if (auto *DIE = Elem.dyn_cast<CXXDefaultInitExpr*>()) {
+ Diag(DIE->getExprLoc(), diag::note_in_default_member_initalizer_here)
+ << DIE->getField();
}
}
return false;
};
- llvm::SmallVector<IndirectLocalPathEntry, 8> Path;
+ llvm::SmallVector<IndirectTemporaryPathEntry, 8> Path;
if (Init->isGLValue())
- visitLocalsRetainedByReferenceBinding(Path, Init, RK_ReferenceBinding,
- TemporaryVisitor);
+ visitTemporariesExtendedByReferenceBinding(Path, Init, EK_ReferenceBinding,
+ TemporaryVisitor);
else
- visitLocalsRetainedByInitializer(Path, Init, TemporaryVisitor, false);
+ visitTemporariesExtendedByInitializer(Path, Init, TemporaryVisitor);
}
static void DiagnoseNarrowingInInitList(Sema &S,
// Diagnose cases where we initialize a pointer to an array temporary, and the
// pointer obviously outlives the temporary.
- // FIXME: Fold this into checkInitializerLifetime.
if (Args.size() == 1 && Args[0]->getType()->isArrayType() &&
Entity.getType()->isPointerType() &&
InitializedEntityOutlivesFullExpression(Entity)) {
}
}
+ // Even though we didn't materialize a temporary, the binding may still
+ // extend the lifetime of a temporary. This happens if we bind a
+ // reference to the result of a cast to reference type.
+ S.checkInitializerLifetime(Entity, CurInit.get());
+
CheckForNullPointerDereference(S, CurInit.get());
break;
Step->Type, CurInit.get(), Entity.getType()->isLValueReferenceType());
CurInit = MTE;
+ // Maybe lifetime-extend the temporary's subobjects to match the
+ // entity's lifetime.
+ S.checkInitializerLifetime(Entity, CurInit.get());
+
// If we're extending this temporary to automatic storage duration -- we
// need to register its cleanup during the full-expression's cleanups.
if (MTE->getStorageDuration() == SD_Automatic &&
// Wrap it in a construction of a std::initializer_list<T>.
CurInit = new (S.Context) CXXStdInitializerListExpr(Step->Type, MTE);
+ // Maybe lifetime-extend the array temporary's subobjects to match the
+ // entity's lifetime.
+ S.checkInitializerLifetime(Entity, CurInit.get());
+
// Bind the result, in case the library has given initializer_list a
// non-trivial destructor.
if (shouldBindAsTemporary(Entity))
}
}
- // Check whether the initializer has a shorter lifetime than the initialized
- // entity, and if not, either lifetime-extend or warn as appropriate.
- if (auto *Init = CurInit.get())
- S.checkInitializerLifetime(Entity, Init);
-
// Diagnose non-fatal problems with the completed initialization.
if (Entity.getKind() == InitializedEntity::EK_Member &&
cast<FieldDecl>(Entity.getDecl())->isBitField())
// X86: @_ZN15partly_constant1kE = global i32 0, align 4
// X86: @_ZN15partly_constant2ilE = global {{.*}} null, align 8
-// X86: @[[PARTLY_CONSTANT_OUTER:_ZGRN15partly_constant2ilE_]] = internal global {{.*}} zeroinitializer, align 8
-// X86: @[[PARTLY_CONSTANT_INNER:_ZGRN15partly_constant2ilE0_]] = internal global [3 x {{.*}}] zeroinitializer, align 8
-// X86: @[[PARTLY_CONSTANT_FIRST:_ZGRN15partly_constant2ilE1_]] = internal constant [3 x i32] [i32 1, i32 2, i32 3], align 4
-// X86: @[[PARTLY_CONSTANT_SECOND:_ZGRN15partly_constant2ilE2_]] = internal global [2 x i32] zeroinitializer, align 4
-// X86: @[[PARTLY_CONSTANT_THIRD:_ZGRN15partly_constant2ilE3_]] = internal constant [4 x i32] [i32 5, i32 6, i32 7, i32 8], align 4
+// X86: @[[PARTLY_CONSTANT_OUTER:_ZGRN15partly_constant2ilE.*]] = internal global {{.*}} zeroinitializer, align 8
+// X86: @[[PARTLY_CONSTANT_INNER:_ZGRN15partly_constant2ilE.*]] = internal global [3 x {{.*}}] zeroinitializer, align 8
+// X86: @[[PARTLY_CONSTANT_FIRST:_ZGRN15partly_constant2ilE.*]] = internal constant [3 x i32] [i32 1, i32 2, i32 3], align 4
+// X86: @[[PARTLY_CONSTANT_SECOND:_ZGRN15partly_constant2ilE.*]] = internal global [2 x i32] zeroinitializer, align 4
+// X86: @[[PARTLY_CONSTANT_THIRD:_ZGRN15partly_constant2ilE.*]] = internal constant [4 x i32] [i32 5, i32 6, i32 7, i32 8], align 4
// AMDGCN: @_ZN15partly_constant1kE = addrspace(1) global i32 0, align 4
// AMDGCN: @_ZN15partly_constant2ilE = addrspace(4) global {{.*}} null, align 8
-// AMDGCN: @[[PARTLY_CONSTANT_OUTER:_ZGRN15partly_constant2ilE_]] = internal addrspace(4) global {{.*}} zeroinitializer, align 8
-// AMDGCN: @[[PARTLY_CONSTANT_INNER:_ZGRN15partly_constant2ilE0_]] = internal addrspace(4) global [3 x {{.*}}] zeroinitializer, align 8
-// AMDGCN: @[[PARTLY_CONSTANT_FIRST:_ZGRN15partly_constant2ilE1_]] = internal addrspace(4) constant [3 x i32] [i32 1, i32 2, i32 3], align 4
-// AMDGCN: @[[PARTLY_CONSTANT_SECOND:_ZGRN15partly_constant2ilE2_]] = internal addrspace(4) global [2 x i32] zeroinitializer, align 4
-// AMDGCN: @[[PARTLY_CONSTANT_THIRD:_ZGRN15partly_constant2ilE3_]] = internal addrspace(4) constant [4 x i32] [i32 5, i32 6, i32 7, i32 8], align 4
+// AMDGCN: @[[PARTLY_CONSTANT_OUTER:_ZGRN15partly_constant2ilE.*]] = internal addrspace(4) global {{.*}} zeroinitializer, align 8
+// AMDGCN: @[[PARTLY_CONSTANT_INNER:_ZGRN15partly_constant2ilE.*]] = internal addrspace(4) global [3 x {{.*}}] zeroinitializer, align 8
+// AMDGCN: @[[PARTLY_CONSTANT_FIRST:_ZGRN15partly_constant2ilE.*]] = internal addrspace(4) constant [3 x i32] [i32 1, i32 2, i32 3], align 4
+// AMDGCN: @[[PARTLY_CONSTANT_SECOND:_ZGRN15partly_constant2ilE.*]] = internal addrspace(4) global [2 x i32] zeroinitializer, align 4
+// AMDGCN: @[[PARTLY_CONSTANT_THIRD:_ZGRN15partly_constant2ilE.*]] = internal addrspace(4) constant [4 x i32] [i32 5, i32 6, i32 7, i32 8], align 4
// X86: @[[REFTMP1:.*]] = private constant [2 x i32] [i32 42, i32 43], align 4
// X86: @[[REFTMP2:.*]] = private constant [3 x %{{.*}}] [%{{.*}} { i32 1 }, %{{.*}} { i32 2 }, %{{.*}} { i32 3 }], align 4
// CHECK-NOT: @[[PARTLY_CONSTANT_THIRD]],
// CHECK: store i32* getelementptr inbounds ({{.*}}, {{.*}}* {{.*}}@[[PARTLY_CONSTANT_THIRD]]{{.*}}, i64 0, i64 0),
// CHECK: i32** getelementptr inbounds ({{.*}}, {{.*}}* {{.*}}@[[PARTLY_CONSTANT_INNER]]{{.*}}, i64 0, i64 2, i32 0)
- // CHECK: store i64 4, i64* getelementptr inbounds ({{.*}}, {{.*}}* {{.*}}@[[PARTLY_CONSTANT_INNER]]{{.*}}, i64 0, i64 2, i32 1)
+ // CHECK: store i64 4, i64* getelementptr inbounds ({{.*}}, {{.*}}* {{.*}}@_ZGRN15partly_constant2ilE4_{{.*}}, i64 0, i64 2, i32 1)
// CHECK-NOT: @[[PARTLY_CONSTANT_THIRD]],
//
// Outer init list.
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