r231049 - Sema: Properly initialize the thrown exception object
Rafael Espíndola
rafael.espindola at gmail.com
Wed Mar 4 08:43:10 PST 2015
No, it looks like it was a llvm change that found a pre existing bug.
On 4 March 2015 at 08:34, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> This might have caused http://llvm.org/bugs/show_bug.cgi?id=22789
>
>
> On 2 March 2015 at 17:50, David Majnemer <david.majnemer at gmail.com> wrote:
>> Author: majnemer
>> Date: Mon Mar 2 19:50:05 2015
>> New Revision: 231049
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=231049&view=rev
>> Log:
>> Sema: Properly initialize the thrown exception object
>>
>> We would create the exception object with the wrong qualifiers, ensuring
>> that the wrong copy constructor would get called.
>>
>> Modified:
>> cfe/trunk/include/clang/AST/ASTContext.h
>> cfe/trunk/lib/AST/ASTContext.cpp
>> cfe/trunk/lib/Sema/SemaExprCXX.cpp
>> cfe/trunk/test/SemaCXX/exceptions.cpp
>>
>> Modified: cfe/trunk/include/clang/AST/ASTContext.h
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ASTContext.h?rev=231049&r1=231048&r2=231049&view=diff
>> ==============================================================================
>> --- cfe/trunk/include/clang/AST/ASTContext.h (original)
>> +++ cfe/trunk/include/clang/AST/ASTContext.h Mon Mar 2 19:50:05 2015
>> @@ -1936,6 +1936,8 @@ public:
>> /// cv-qualifiers.
>> QualType getSignatureParameterType(QualType T) const;
>>
>> + QualType getExceptionObjectType(QualType T) const;
>> +
>> /// \brief Return the properly qualified result of decaying the specified
>> /// array type to a pointer.
>> ///
>>
>> Modified: cfe/trunk/lib/AST/ASTContext.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTContext.cpp?rev=231049&r1=231048&r2=231049&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/AST/ASTContext.cpp (original)
>> +++ cfe/trunk/lib/AST/ASTContext.cpp Mon Mar 2 19:50:05 2015
>> @@ -4338,6 +4338,19 @@ QualType ASTContext::getSignatureParamet
>> return T.getUnqualifiedType();
>> }
>>
>> +QualType ASTContext::getExceptionObjectType(QualType T) const {
>> + // C++ [except.throw]p3:
>> + // A throw-expression initializes a temporary object, called the exception
>> + // object, the type of which is determined by removing any top-level
>> + // cv-qualifiers from the static type of the operand of throw and adjusting
>> + // the type from "array of T" or "function returning T" to "pointer to T"
>> + // or "pointer to function returning T", [...]
>> + T = getVariableArrayDecayedType(T);
>> + if (T->isArrayType() || T->isFunctionType())
>> + T = getDecayedType(T);
>> + return T.getUnqualifiedType();
>> +}
>> +
>> /// getArrayDecayedType - Return the properly qualified result of decaying the
>> /// specified array type to a pointer. This operation is non-trivial when
>> /// handling typedefs etc. The canonical type of "T" must be an array type,
>>
>> Modified: cfe/trunk/lib/Sema/SemaExprCXX.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExprCXX.cpp?rev=231049&r1=231048&r2=231049&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/Sema/SemaExprCXX.cpp (original)
>> +++ cfe/trunk/lib/Sema/SemaExprCXX.cpp Mon Mar 2 19:50:05 2015
>> @@ -660,24 +660,10 @@ ExprResult Sema::BuildCXXThrow(SourceLoc
>> /// CheckCXXThrowOperand - Validate the operand of a throw.
>> ExprResult Sema::CheckCXXThrowOperand(SourceLocation ThrowLoc, Expr *E,
>> bool IsThrownVarInScope) {
>> - // C++ [except.throw]p3:
>> - // A throw-expression initializes a temporary object, called the exception
>> - // object, the type of which is determined by removing any top-level
>> - // cv-qualifiers from the static type of the operand of throw and adjusting
>> - // the type from "array of T" or "function returning T" to "pointer to T"
>> - // or "pointer to function returning T", [...]
>> - if (E->getType().hasQualifiers())
>> - E = ImpCastExprToType(E, E->getType().getUnqualifiedType(), CK_NoOp,
>> - E->getValueKind()).get();
>> -
>> - ExprResult Res = DefaultFunctionArrayConversion(E);
>> - if (Res.isInvalid())
>> - return ExprError();
>> - E = Res.get();
>> -
>> + QualType ExceptionObjectTy = Context.getExceptionObjectType(E->getType());
>> // If the type of the exception would be an incomplete type or a pointer
>> // to an incomplete type other than (cv) void the program is ill-formed.
>> - QualType Ty = E->getType();
>> + QualType Ty = ExceptionObjectTy;
>> bool isPointer = false;
>> if (const PointerType* Ptr = Ty->getAs<PointerType>()) {
>> Ty = Ptr->getPointeeType();
>> @@ -690,7 +676,7 @@ ExprResult Sema::CheckCXXThrowOperand(So
>> E->getSourceRange()))
>> return ExprError();
>>
>> - if (RequireNonAbstractType(ThrowLoc, E->getType(),
>> + if (RequireNonAbstractType(ThrowLoc, ExceptionObjectTy,
>> diag::err_throw_abstract_type, E))
>> return ExprError();
>> }
>> @@ -714,11 +700,10 @@ ExprResult Sema::CheckCXXThrowOperand(So
>> NRVOVariable = getCopyElisionCandidate(QualType(), E, false);
>>
>> InitializedEntity Entity =
>> - InitializedEntity::InitializeException(ThrowLoc, E->getType(),
>> + InitializedEntity::InitializeException(ThrowLoc, ExceptionObjectTy,
>> /*NRVO=*/NRVOVariable != nullptr);
>> - Res = PerformMoveOrCopyInitialization(Entity, NRVOVariable,
>> - QualType(), E,
>> - IsThrownVarInScope);
>> + ExprResult Res = PerformMoveOrCopyInitialization(
>> + Entity, NRVOVariable, QualType(), E, IsThrownVarInScope);
>> if (Res.isInvalid())
>> return ExprError();
>> E = Res.get();
>>
>> Modified: cfe/trunk/test/SemaCXX/exceptions.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/exceptions.cpp?rev=231049&r1=231048&r2=231049&view=diff
>> ==============================================================================
>> --- cfe/trunk/test/SemaCXX/exceptions.cpp (original)
>> +++ cfe/trunk/test/SemaCXX/exceptions.cpp Mon Mar 2 19:50:05 2015
>> @@ -145,3 +145,16 @@ namespace Decay {
>> }
>>
>> void rval_ref() throw (int &&); // expected-error {{rvalue reference type 'int &&' is not allowed in exception specification}} expected-warning {{C++11}}
>> +
>> +namespace ConstVolatile {
>> +struct S {
>> + S() {} // expected-note{{candidate constructor not viable}}
>> + S(const S &s); // expected-note{{candidate constructor not viable}}
>> +};
>> +
>> +typedef const volatile S CVS;
>> +
>> +void f() {
>> + throw CVS(); // expected-error{{no matching constructor for initialization}}
>> +}
>> +}
>>
>>
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