* [PATCH] c++: Fix up build_m_component_ref [PR113599]
@ 2024-01-25 19:14 Jakub Jelinek
2024-01-25 19:33 ` Patrick Palka
2024-01-25 23:04 ` Jason Merrill
0 siblings, 2 replies; 4+ messages in thread
From: Jakub Jelinek @ 2024-01-25 19:14 UTC (permalink / raw)
To: Jason Merrill; +Cc: gcc-patches, Patrick Palka
Hi!
The following testcase reduced from GDB is miscompiled starting with
r14-5503 PR112427 change.
The problem is in the build_m_component_ref hunk, which changed
- datum = fold_build_pointer_plus (fold_convert (ptype, datum), component);
+ datum = cp_convert (ptype, datum, complain);
+ if (!processing_template_decl)
+ datum = build2 (POINTER_PLUS_EXPR, ptype,
+ datum, convert_to_ptrofftype (component));
+ datum = cp_fully_fold (datum);
Component is e, (sizetype) e is 16, offset of c inside of C.
ptype is A *, pointer to type of C::c and datum is &d.
Now, previously the above created ((A *) &d) p+ (sizetype) e which is correct,
but in the new code cp_convert sees that C has A as base class and
instead of returning (A *) &d, it returns &d.D.2800 where D.2800 is
the FIELD_DECL for the A base at offset 8 into C.
So, instead of computing ((A *) &d) p+ (sizetype) e it computes
&d.D.2800 p+ (sizetype) e, which is ((A *) &d) p+ 24.
The following patch fixes it by using convert instead of cp_convert which
eventually calls build_nop (ptype, datum).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2024-01-25 Jakub Jelinek <jakub@redhat.com>
PR c++/113599
* typeck2.cc (build_m_component_ref): Use convert instead of
cp_convert for pointer conversion.
* g++.dg/expr/ptrmem11.C: New test.
--- gcc/cp/typeck2.cc.jj 2024-01-03 12:01:23.672476417 +0100
+++ gcc/cp/typeck2.cc 2024-01-25 14:11:40.656361310 +0100
@@ -2378,7 +2378,7 @@ build_m_component_ref (tree datum, tree
/* Build an expression for "object + offset" where offset is the
value stored in the pointer-to-data-member. */
ptype = build_pointer_type (type);
- datum = cp_convert (ptype, datum, complain);
+ datum = convert (ptype, datum);
if (!processing_template_decl)
datum = build2 (POINTER_PLUS_EXPR, ptype,
datum, convert_to_ptrofftype (component));
--- gcc/testsuite/g++.dg/expr/ptrmem11.C.jj 2024-01-25 14:13:11.736089567 +0100
+++ gcc/testsuite/g++.dg/expr/ptrmem11.C 2024-01-25 14:18:47.720398222 +0100
@@ -0,0 +1,17 @@
+// PR c++/113599
+// { dg-do run }
+
+struct A { void *a; };
+struct B { void *b; };
+struct C : public B, public A { A c; };
+static C d;
+
+int
+main ()
+{
+ A C::*e = &C::c;
+ A *f = &(d.*e);
+ A *g = &d.c;
+ if (f != g)
+ __builtin_abort ();
+}
Jakub
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] c++: Fix up build_m_component_ref [PR113599]
2024-01-25 19:14 [PATCH] c++: Fix up build_m_component_ref [PR113599] Jakub Jelinek
@ 2024-01-25 19:33 ` Patrick Palka
2024-01-25 19:37 ` Patrick Palka
2024-01-25 23:04 ` Jason Merrill
1 sibling, 1 reply; 4+ messages in thread
From: Patrick Palka @ 2024-01-25 19:33 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: Jason Merrill, gcc-patches, Patrick Palka
On Thu, 25 Jan 2024, Jakub Jelinek wrote:
> Hi!
>
> The following testcase reduced from GDB is miscompiled starting with
> r14-5503 PR112427 change.
> The problem is in the build_m_component_ref hunk, which changed
> - datum = fold_build_pointer_plus (fold_convert (ptype, datum), component);
> + datum = cp_convert (ptype, datum, complain);
> + if (!processing_template_decl)
> + datum = build2 (POINTER_PLUS_EXPR, ptype,
> + datum, convert_to_ptrofftype (component));
> + datum = cp_fully_fold (datum);
> Component is e, (sizetype) e is 16, offset of c inside of C.
> ptype is A *, pointer to type of C::c and datum is &d.
> Now, previously the above created ((A *) &d) p+ (sizetype) e which is correct,
> but in the new code cp_convert sees that C has A as base class and
> instead of returning (A *) &d, it returns &d.D.2800 where D.2800 is
> the FIELD_DECL for the A base at offset 8 into C.
> So, instead of computing ((A *) &d) p+ (sizetype) e it computes
> &d.D.2800 p+ (sizetype) e, which is ((A *) &d) p+ 24.
>
> The following patch fixes it by using convert instead of cp_convert which
> eventually calls build_nop (ptype, datum).
LGTM. IIUC using 'convert' would work here too thanks to its special
case for indirect types, but I naively went with cp_convert since it has
a complain parameter :/
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2024-01-25 Jakub Jelinek <jakub@redhat.com>
>
> PR c++/113599
> * typeck2.cc (build_m_component_ref): Use convert instead of
> cp_convert for pointer conversion.
>
> * g++.dg/expr/ptrmem11.C: New test.
>
> --- gcc/cp/typeck2.cc.jj 2024-01-03 12:01:23.672476417 +0100
> +++ gcc/cp/typeck2.cc 2024-01-25 14:11:40.656361310 +0100
> @@ -2378,7 +2378,7 @@ build_m_component_ref (tree datum, tree
> /* Build an expression for "object + offset" where offset is the
> value stored in the pointer-to-data-member. */
> ptype = build_pointer_type (type);
> - datum = cp_convert (ptype, datum, complain);
> + datum = convert (ptype, datum);
> if (!processing_template_decl)
> datum = build2 (POINTER_PLUS_EXPR, ptype,
> datum, convert_to_ptrofftype (component));
> --- gcc/testsuite/g++.dg/expr/ptrmem11.C.jj 2024-01-25 14:13:11.736089567 +0100
> +++ gcc/testsuite/g++.dg/expr/ptrmem11.C 2024-01-25 14:18:47.720398222 +0100
> @@ -0,0 +1,17 @@
> +// PR c++/113599
> +// { dg-do run }
> +
> +struct A { void *a; };
> +struct B { void *b; };
> +struct C : public B, public A { A c; };
> +static C d;
> +
> +int
> +main ()
> +{
> + A C::*e = &C::c;
> + A *f = &(d.*e);
> + A *g = &d.c;
> + if (f != g)
> + __builtin_abort ();
> +}
>
> Jakub
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] c++: Fix up build_m_component_ref [PR113599]
2024-01-25 19:33 ` Patrick Palka
@ 2024-01-25 19:37 ` Patrick Palka
0 siblings, 0 replies; 4+ messages in thread
From: Patrick Palka @ 2024-01-25 19:37 UTC (permalink / raw)
To: Patrick Palka; +Cc: Jakub Jelinek, Jason Merrill, gcc-patches
On Thu, 25 Jan 2024, Patrick Palka wrote:
> On Thu, 25 Jan 2024, Jakub Jelinek wrote:
>
> > Hi!
> >
> > The following testcase reduced from GDB is miscompiled starting with
> > r14-5503 PR112427 change.
> > The problem is in the build_m_component_ref hunk, which changed
> > - datum = fold_build_pointer_plus (fold_convert (ptype, datum), component);
> > + datum = cp_convert (ptype, datum, complain);
> > + if (!processing_template_decl)
> > + datum = build2 (POINTER_PLUS_EXPR, ptype,
> > + datum, convert_to_ptrofftype (component));
> > + datum = cp_fully_fold (datum);
> > Component is e, (sizetype) e is 16, offset of c inside of C.
> > ptype is A *, pointer to type of C::c and datum is &d.
> > Now, previously the above created ((A *) &d) p+ (sizetype) e which is correct,
> > but in the new code cp_convert sees that C has A as base class and
> > instead of returning (A *) &d, it returns &d.D.2800 where D.2800 is
> > the FIELD_DECL for the A base at offset 8 into C.
> > So, instead of computing ((A *) &d) p+ (sizetype) e it computes
> > &d.D.2800 p+ (sizetype) e, which is ((A *) &d) p+ 24.
> >
> > The following patch fixes it by using convert instead of cp_convert which
> > eventually calls build_nop (ptype, datum).
>
> LGTM. IIUC using 'convert' would work here too thanks to its special
> case for indirect types, but I naively went with cp_convert since it has
> a complain parameter :/
D'oh, I completely overlooked this version of the patch already uses
convert instead of build_nop directly :) LGTM either way
>
> >
> > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
> >
> > 2024-01-25 Jakub Jelinek <jakub@redhat.com>
> >
> > PR c++/113599
> > * typeck2.cc (build_m_component_ref): Use convert instead of
> > cp_convert for pointer conversion.
> >
> > * g++.dg/expr/ptrmem11.C: New test.
> >
> > --- gcc/cp/typeck2.cc.jj 2024-01-03 12:01:23.672476417 +0100
> > +++ gcc/cp/typeck2.cc 2024-01-25 14:11:40.656361310 +0100
> > @@ -2378,7 +2378,7 @@ build_m_component_ref (tree datum, tree
> > /* Build an expression for "object + offset" where offset is the
> > value stored in the pointer-to-data-member. */
> > ptype = build_pointer_type (type);
> > - datum = cp_convert (ptype, datum, complain);
> > + datum = convert (ptype, datum);
> > if (!processing_template_decl)
> > datum = build2 (POINTER_PLUS_EXPR, ptype,
> > datum, convert_to_ptrofftype (component));
> > --- gcc/testsuite/g++.dg/expr/ptrmem11.C.jj 2024-01-25 14:13:11.736089567 +0100
> > +++ gcc/testsuite/g++.dg/expr/ptrmem11.C 2024-01-25 14:18:47.720398222 +0100
> > @@ -0,0 +1,17 @@
> > +// PR c++/113599
> > +// { dg-do run }
> > +
> > +struct A { void *a; };
> > +struct B { void *b; };
> > +struct C : public B, public A { A c; };
> > +static C d;
> > +
> > +int
> > +main ()
> > +{
> > + A C::*e = &C::c;
> > + A *f = &(d.*e);
> > + A *g = &d.c;
> > + if (f != g)
> > + __builtin_abort ();
> > +}
> >
> > Jakub
> >
> >
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] c++: Fix up build_m_component_ref [PR113599]
2024-01-25 19:14 [PATCH] c++: Fix up build_m_component_ref [PR113599] Jakub Jelinek
2024-01-25 19:33 ` Patrick Palka
@ 2024-01-25 23:04 ` Jason Merrill
1 sibling, 0 replies; 4+ messages in thread
From: Jason Merrill @ 2024-01-25 23:04 UTC (permalink / raw)
To: Jakub Jelinek; +Cc: gcc-patches, Patrick Palka
On 1/25/24 14:14, Jakub Jelinek wrote:
> Hi!
>
> The following testcase reduced from GDB is miscompiled starting with
> r14-5503 PR112427 change.
> The problem is in the build_m_component_ref hunk, which changed
> - datum = fold_build_pointer_plus (fold_convert (ptype, datum), component);
> + datum = cp_convert (ptype, datum, complain);
> + if (!processing_template_decl)
> + datum = build2 (POINTER_PLUS_EXPR, ptype,
> + datum, convert_to_ptrofftype (component));
> + datum = cp_fully_fold (datum);
> Component is e, (sizetype) e is 16, offset of c inside of C.
> ptype is A *, pointer to type of C::c and datum is &d.
> Now, previously the above created ((A *) &d) p+ (sizetype) e which is correct,
> but in the new code cp_convert sees that C has A as base class and
> instead of returning (A *) &d, it returns &d.D.2800 where D.2800 is
> the FIELD_DECL for the A base at offset 8 into C.
> So, instead of computing ((A *) &d) p+ (sizetype) e it computes
> &d.D.2800 p+ (sizetype) e, which is ((A *) &d) p+ 24.
>
> The following patch fixes it by using convert instead of cp_convert which
> eventually calls build_nop (ptype, datum).
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK
> 2024-01-25 Jakub Jelinek <jakub@redhat.com>
>
> PR c++/113599
> * typeck2.cc (build_m_component_ref): Use convert instead of
> cp_convert for pointer conversion.
>
> * g++.dg/expr/ptrmem11.C: New test.
>
> --- gcc/cp/typeck2.cc.jj 2024-01-03 12:01:23.672476417 +0100
> +++ gcc/cp/typeck2.cc 2024-01-25 14:11:40.656361310 +0100
> @@ -2378,7 +2378,7 @@ build_m_component_ref (tree datum, tree
> /* Build an expression for "object + offset" where offset is the
> value stored in the pointer-to-data-member. */
> ptype = build_pointer_type (type);
> - datum = cp_convert (ptype, datum, complain);
> + datum = convert (ptype, datum);
> if (!processing_template_decl)
> datum = build2 (POINTER_PLUS_EXPR, ptype,
> datum, convert_to_ptrofftype (component));
> --- gcc/testsuite/g++.dg/expr/ptrmem11.C.jj 2024-01-25 14:13:11.736089567 +0100
> +++ gcc/testsuite/g++.dg/expr/ptrmem11.C 2024-01-25 14:18:47.720398222 +0100
> @@ -0,0 +1,17 @@
> +// PR c++/113599
> +// { dg-do run }
> +
> +struct A { void *a; };
> +struct B { void *b; };
> +struct C : public B, public A { A c; };
> +static C d;
> +
> +int
> +main ()
> +{
> + A C::*e = &C::c;
> + A *f = &(d.*e);
> + A *g = &d.c;
> + if (f != g)
> + __builtin_abort ();
> +}
>
> Jakub
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2024-01-25 19:14 [PATCH] c++: Fix up build_m_component_ref [PR113599] Jakub Jelinek
2024-01-25 19:33 ` Patrick Palka
2024-01-25 19:37 ` Patrick Palka
2024-01-25 23:04 ` Jason Merrill
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