r199374 - Sema: Fix crash during member pointer conversion involving incomplete classes

[Reid Kleckner]

Nice!  It wasn't even a bug in MS ABI code.  :)


On Thu, Jan 16, 2014 at 4:02 AM, David Majnemer <david.majnemer at gmail.com>wrote:

> Author: majnemer
> Date: Thu Jan 16 06:02:55 2014
> New Revision: 199374
>
> URL: http://llvm.org/viewvc/llvm-project?rev=199374&view=rev
> Log:
> Sema: Fix crash during member pointer conversion involving incomplete
> classes
>
> We would attempt to determine the inheritance relationship between
> classes 'A' and 'B' during static_cast if we tried to convert from 'int
> A::*' to 'int B::*'.  However, the question "does A derive from B" is
> not meaningful when 'A' isn't defined.
>
> Handle this case by requiring that 'A' be defined.
>
> This fixes PR18506.
>
> Modified:
>     cfe/trunk/lib/Sema/SemaCast.cpp
>     cfe/trunk/test/SemaCXX/static-cast.cpp
>
> Modified: cfe/trunk/lib/Sema/SemaCast.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaCast.cpp?rev=199374&r1=199373&r2=199374&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaCast.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaCast.cpp Thu Jan 16 06:02:55 2014
> @@ -1346,7 +1346,8 @@ TryStaticMemberPointerUpcast(Sema &Self,
>    QualType DestClass(DestMemPtr->getClass(), 0);
>    CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
>                    /*DetectVirtual=*/true);
> -  if (!Self.IsDerivedFrom(SrcClass, DestClass, Paths)) {
> +  if (Self.RequireCompleteType(OpRange.getBegin(), SrcClass, 0) ||
> +      !Self.IsDerivedFrom(SrcClass, DestClass, Paths)) {
>      return TC_NotApplicable;
>    }
>
>
> Modified: cfe/trunk/test/SemaCXX/static-cast.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/static-cast.cpp?rev=199374&r1=199373&r2=199374&view=diff
>
> ==============================================================================
> --- cfe/trunk/test/SemaCXX/static-cast.cpp (original)
> +++ cfe/trunk/test/SemaCXX/static-cast.cpp Thu Jan 16 06:02:55 2014
> @@ -9,6 +9,8 @@ struct F : public C1 {};            // S
>  struct G1 : public B {};
>  struct G2 : public B {};
>  struct H : public G1, public G2 {}; // Ambiguous path to B.
> +struct I;                           // Incomplete.
> +struct J;                           // Incomplete.
>
>  enum Enum { En1, En2 };
>  enum Onom { On1, On2 };
> @@ -131,6 +133,7 @@ void t_529_9()
>    // Bad code below
>    (void)static_cast<int A::*>((int H::*)0); // expected-error {{ambiguous
> conversion from pointer to member of derived class 'H' to pointer to member
> of base class 'A':}}
>    (void)static_cast<int A::*>((int F::*)0); // expected-error
> {{conversion from pointer to member of class 'F' to pointer to member of
> class 'A' via virtual base 'B' is not allowed}}
> +  (void)static_cast<int I::*>((int J::*)0); // expected-error
> {{static_cast from 'int J::*' to 'int I::*' is not allowed}}
>  }
>
>  // PR 5261 - static_cast should instantiate template if possible
>
>
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