The patch failed so I’ve reverted the offending commit for the
moment; commit r15-4301-ga4eec6c712ec16 refers.
I’ll work on a resubmit via the initial PR (109918).
Apologies for the breakage.
Simon
On 13 Oct 2024, at 13:55, Simon Martin wrote:
> The patch that I merged via r15-4282-g60163c85730e6b breaks the build
> for the rust front-end because it does not work well when virtual
> inheritance is in play.
>
> The problem is that in such a case, an overrider and its overridden
> base
> method might have a different DECL_VINDEX, and the derived method
> would
> be incorrectly considered as hiding the base one.
>
> This patch fixes this by not comparing the DECL_VINDEX anymore, but
> rather going back to comparing the signatures, only after having
> excluded conversion operators to different types.
>
> I'm currently running the testsuite on x86_64-pc-linux-gnu, and
> already
> verified that the rust front-end builds again with the patch applied.
>
> OK if the testsuite run finishes successfully?
>
> PR c++/117114
>
> gcc/cp/ChangeLog:
>
> * class.cc (warn_hidden): Don't compare DECL_VINDEX but
> signatures, after having excluded operators to different types.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/warn/Woverloaded-virt10.C: New test.
>
> ---
> gcc/cp/class.cc | 20
> +++++++++----------
> .../g++.dg/warn/Woverloaded-virt10.C | 7 +++++++
> 2 files changed, 17 insertions(+), 10 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/warn/Woverloaded-virt10.C
>
> diff --git a/gcc/cp/class.cc b/gcc/cp/class.cc
> index f754886a60a..fce71483ccc 100644
> --- a/gcc/cp/class.cc
> +++ b/gcc/cp/class.cc
> @@ -3279,25 +3279,25 @@ warn_hidden (tree t)
> {
> num_fns++;
> tree fndecl_vindex = DECL_VINDEX (fndecl);
> - /* If the method from the base class has the same DECL_VINDEX
> - as the method from the derived, it has been overridden.
> + /* If the methods from the base and derived classes have the
> + same signature and they are not conversion operators to
> + different types, then the base method has been overriden.
> Note that we can't move on after finding one match: fndecl
> might override multiple base fns. */
> for (size_t k = 0; k < base_fndecls.length (); k++)
> {
> if (!base_fndecls[k] || !DECL_VINDEX (base_fndecls[k]))
> continue;
> - tree base_fndecl_vindex = DECL_VINDEX (base_fndecls[k]);
> - if (fndecl_vindex
> - && !tree_int_cst_compare (fndecl_vindex,
> - base_fndecl_vindex))
> - overriden_base_fndecls.add (base_fndecls[k]);
> - else if (IDENTIFIER_CONV_OP_P (name)
> - && (DECL_NAME (fndecl)
> - != DECL_NAME (base_fndecls[k])))
> + if (IDENTIFIER_CONV_OP_P (name)
> + && (DECL_NAME (fndecl)
> + != DECL_NAME (base_fndecls[k])))
> /* If base_fndecl[k] and fndecl are conversion operators
> to different types, they're unrelated. */
> ;
> + else if (same_signature_p (fndecl, base_fndecls[k]))
> + /* If fndecl has the same signature as base_fndecl[k], it
> + overrides it. */
> + overriden_base_fndecls.add (base_fndecls[k]);
> else
> hidden_base_fndecls.put (base_fndecls[k], fndecl);
> }
> diff --git a/gcc/testsuite/g++.dg/warn/Woverloaded-virt10.C
> b/gcc/testsuite/g++.dg/warn/Woverloaded-virt10.C
> new file mode 100644
> index 00000000000..5e669360ec9
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/warn/Woverloaded-virt10.C
> @@ -0,0 +1,7 @@
> +// PR c++/117114
> +// { dg-do compile { target c++11 } }
> +// { dg-additional-options -Wall }
> +
> +struct Troops { virtual ~Troops(); };
> +struct Control { virtual int GetControl() const = 0; };
> +struct Army : Troops, Control { int GetControl() const override; };
> --
> 2.44.0
