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Fix handling of pointers-to-members and comma expressions when 

lifetime-extending temporaries in reference bindings.

llvm-svn: 183089
This commit is contained in:
Richard Smith 2013-06-03 00:17:11 +00:00
parent 0bbe1b210e
commit f3fabd2cb5
5 changed files with 76 additions and 11 deletions
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8
clang/include/clang/AST/Expr.h
View File

@ -760,10 +760,10 @@ public:
/// Walk outwards from an expression we want to bind a reference to and
/// find the expression whose lifetime needs to be extended. Record
/// the adjustments needed along the path.
const Expr *
skipRValueSubobjectAdjustments(
SmallVectorImpl<SubobjectAdjustment> &Adjustments) const;
/// the LHSs of comma expressions and adjustments needed along the path.
const Expr *skipRValueSubobjectAdjustments(
SmallVectorImpl<const Expr *> &CommaLHS,
SmallVectorImpl<SubobjectAdjustment> &Adjustments) const;
/// Skip irrelevant expressions to find what should be materialize for
/// binding with a reference.

11
clang/lib/AST/Expr.cpp
View File

@ -50,9 +50,9 @@ const CXXRecordDecl *Expr::getBestDynamicClassType() const {
return cast<CXXRecordDecl>(D);
}
const Expr *
Expr::skipRValueSubobjectAdjustments(
SmallVectorImpl<SubobjectAdjustment> &Adjustments) const {
const Expr *Expr::skipRValueSubobjectAdjustments(
SmallVectorImpl<const Expr *> &CommaLHSs,
SmallVectorImpl<SubobjectAdjustment> &Adjustments) const {
const Expr *E = this;
while (true) {
E = E->IgnoreParens();
@ -88,6 +88,11 @@ Expr::skipRValueSubobjectAdjustments(
const MemberPointerType *MPT =
BO->getRHS()->getType()->getAs<MemberPointerType>();
Adjustments.push_back(SubobjectAdjustment(MPT, BO->getRHS()));
continue;
} else if (BO->getOpcode() == BO_Comma) {
CommaLHSs.push_back(BO->getLHS());
E = BO->getRHS();
continue;
}
}

11
clang/lib/CodeGen/CGExpr.cpp
View File

@ -295,8 +295,13 @@ EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
return ReferenceTemporary;
}
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
E = E->skipRValueSubobjectAdjustments(Adjustments);
E = E->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
for (unsigned I = 0, N = CommaLHSs.size(); I != N; ++I)
CGF.EmitIgnoredExpr(CommaLHSs[I]);
if (const OpaqueValueExpr *opaque = dyn_cast<OpaqueValueExpr>(E))
if (opaque->getType()->isRecordType())
return CGF.EmitOpaqueValueLValue(opaque).getAddress();
@ -332,6 +337,10 @@ EmitExprForReferenceBinding(CodeGenFunction &CGF, const Expr *E,
RValue RV = CGF.EmitAnyExpr(E, AggSlot);
// FIXME: This is wrong. We need to register the destructor for the temporary
// now, *before* we perform the adjustments, because in the case of a
// pointer-to-member adjustment, the adjustment might throw.
// Check if need to perform derived-to-base casts and/or field accesses, to
// get from the temporary object we created (and, potentially, for which we
// extended the lifetime) to the subobject we're binding the reference to.

9
clang/lib/Sema/JumpDiagnostics.cpp
View File

@ -172,14 +172,19 @@ static ScopePair GetDiagForGotoScopeDecl(ASTContext &Context, const Decl *D) {
if (EWC)
Init = EWC->getSubExpr();
// FIXME: Why are we looking through reference initialization?
// This causes us to incorrectly accept invalid code such as:
// struct S { int n; };
// int f() { goto x; S &&s = S(); x: return x.n; }
const MaterializeTemporaryExpr *M = NULL;
Init = Init->findMaterializedTemporary(M);
SmallVector<const Expr *, 2> CommaLHSs;
SmallVector<SubobjectAdjustment, 2> Adjustments;
Init = Init->skipRValueSubobjectAdjustments(Adjustments);
Init = Init->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
QualType QT = Init->getType();
if (QT.isNull())
if (QT.isNull() || !CommaLHSs.empty())
return ScopePair(diag::note_protected_by_variable_init, 0);
const Type *T = QT.getTypePtr();

48
clang/test/CodeGenCXX/temporaries.cpp
View File

@ -1,4 +1,4 @@
// RUN: %clang_cc1 -emit-llvm %s -o - -triple=x86_64-apple-darwin9 | FileCheck %s
// RUN: %clang_cc1 -emit-llvm %s -o - -triple=x86_64-apple-darwin9 -std=c++11 | FileCheck %s
struct A {
A();
~A();
@ -558,3 +558,49 @@ namespace AssignmentOp {
// CHECK: call {{.*}} @_ZN12AssignmentOp1BaSERKS
// CHECK: call {{.*}} @_ZN12AssignmentOp1AD1Ev(
}
namespace BindToSubobject {
struct A {
A();
~A();
int a;
};
void f(), g();
// CHECK: call void @_ZN15BindToSubobject1AC1Ev({{.*}} @_ZGRN15BindToSubobject1aE)
// CHECK: call i32 @__cxa_atexit({{.*}} bitcast ({{.*}} @_ZN15BindToSubobject1AD1Ev to void (i8*)*), i8* bitcast ({{.*}} @_ZGRN15BindToSubobject1aE to i8*), i8* @__dso_handle)
// CHECK: store i32* getelementptr inbounds ({{.*}} @_ZGRN15BindToSubobject1aE, i32 0, i32 0), i32** @_ZN15BindToSubobject1aE, align 8
int &&a = A().a;
// CHECK: call void @_ZN15BindToSubobject1fEv()
// CHECK: call void @_ZN15BindToSubobject1AC1Ev({{.*}} @_ZGRN15BindToSubobject1bE)
// CHECK: call i32 @__cxa_atexit({{.*}} bitcast ({{.*}} @_ZN15BindToSubobject1AD1Ev to void (i8*)*), i8* bitcast ({{.*}} @_ZGRN15BindToSubobject1bE to i8*), i8* @__dso_handle)
// CHECK: store i32* getelementptr inbounds ({{.*}} @_ZGRN15BindToSubobject1bE, i32 0, i32 0), i32** @_ZN15BindToSubobject1bE, align 8
int &&b = (f(), A().a);
int A::*h();
// CHECK: call void @_ZN15BindToSubobject1fEv()
// CHECK: call void @_ZN15BindToSubobject1gEv()
// CHECK: call void @_ZN15BindToSubobject1AC1Ev({{.*}} @_ZGRN15BindToSubobject1cE)
// FIXME: This is wrong. We should emit the call to __cxa_atexit prior to
// calling h(), in case h() throws.
// CHECK: call {{.*}} @_ZN15BindToSubobject1hE
// CHECK: getelementptr
// CHECK: call i32 @__cxa_atexit({{.*}} bitcast ({{.*}} @_ZN15BindToSubobject1AD1Ev to void (i8*)*), i8* bitcast ({{.*}} @_ZGRN15BindToSubobject1cE to i8*), i8* @__dso_handle)
// CHECK: store i32* {{.*}}, i32** @_ZN15BindToSubobject1cE, align 8
int &&c = (f(), (g(), A().*h()));
struct B {
int padding;
A a;
};
// CHECK: call void @_ZN15BindToSubobject1BC1Ev({{.*}} @_ZGRN15BindToSubobject1dE)
// CHECK: call {{.*}} @_ZN15BindToSubobject1hE
// CHECK: getelementptr {{.*}} getelementptr
// CHECK: call i32 @__cxa_atexit({{.*}} bitcast ({{.*}} @_ZN15BindToSubobject1BD1Ev to void (i8*)*), i8* bitcast ({{.*}} @_ZGRN15BindToSubobject1dE to i8*), i8* @__dso_handle)
// CHECK: store i32* {{.*}}, i32** @_ZN15BindToSubobject1dE, align 8
int &&d = (B().a).*h();
}