On Fri, Jul 16, 2021 at 10:23 PM Hafiz Abid Qadeer
<abid_qad...@mentor.com> wrote:
>
> On 15/07/2021 13:09, Richard Biener wrote:
> > On Thu, Jul 15, 2021 at 12:35 PM Hafiz Abid Qadeer
> > <abid_qad...@mentor.com> wrote:
> >>
> >> On 15/07/2021 11:33, Thomas Schwinge wrote:
> >>>
> >>>> Note that the "parent" should be abstract but I don't think dwarf has a
> >>>> way to express a fully abstract parent of a concrete instance child - or
> >>>> at least how GCC expresses this causes consumers to "misinterpret"
> >>>> that. I wonder if adding a DW_AT_declaration to the late DWARF
> >>>> emitted "parent" would fix things as well here?
> >>>
> >>> (I suppose not, Abid?)
> >>>
> >>
> >> Yes, adding DW_AT_declaration does not fix the problem.
> >
> > Does emitting
> >
> > DW_TAG_compile_unit
> > DW_AT_name ("<artificial>")
> >
> > DW_TAG_subprogram // notional parent function (foo) with no code range
> > DW_AT_declaration 1
> > a: DW_TAG_subprogram // offload function foo._omp_fn.0
> > DW_AT_declaration 1
> >
> > DW_TAG_subprogram // offload function
> > DW_AT_abstract_origin a
> > ...
> >
> > do the trick? The following would do this, flattening function definitions
> > for the concrete copies:
> >
> > diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
> > index 82783c4968b..a9c8bc43e88 100644
> > --- a/gcc/dwarf2out.c
> > +++ b/gcc/dwarf2out.c
> > @@ -6076,6 +6076,11 @@ maybe_create_die_with_external_ref (tree decl)
> > /* Peel types in the context stack. */
> > while (ctx && TYPE_P (ctx))
> > ctx = TYPE_CONTEXT (ctx);
> > + /* For functions peel the context up to namespace/TU scope. The abstract
> > + copies reveal the true nesting. */
> > + if (TREE_CODE (decl) == FUNCTION_DECL)
> > + while (ctx && TREE_CODE (ctx) == FUNCTION_DECL)
> > + ctx = DECL_CONTEXT (ctx);
> > /* Likewise namespaces in case we do not want to emit DIEs for them. */
> > if (debug_info_level <= DINFO_LEVEL_TERSE)
> > while (ctx && TREE_CODE (ctx) == NAMESPACE_DECL)
> > @@ -6099,8 +6104,7 @@ maybe_create_die_with_external_ref (tree decl)
> > /* Leave function local entities parent determination to when
> > we process scope vars. */
> > ;
> > - else
> > - parent = lookup_decl_die (ctx);
> > + parent = lookup_decl_die (ctx);
> > }
> > else
> > /* In some cases the FEs fail to set DECL_CONTEXT properly.
> >
>
> Thanks. This solves the problem. Only the first hunk was required. Second hunk
> actually causes an ICE when TREE_CODE (ctx) == BLOCK.
> OK to commit the attached patch?
I think we need to merge the TYPE_P peeling and FUNCTION_DECL peeling into
one loop since I suppose we can have a nested function in class scope.
So sth like
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 82783c4968b..61228410b51 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -6073,8 +6073,12 @@ maybe_create_die_with_external_ref (tree decl)
}
else
ctx = DECL_CONTEXT (decl);
- /* Peel types in the context stack. */
- while (ctx && TYPE_P (ctx))
+ /* Peel types in the context stack. For functions peel the context up
+ to namespace/TU scope. The abstract copies reveal the true nesting. */
+ while (ctx
+ && (TYPE_P (ctx)
+ || (TREE_CODE (decl) == FUNCTION_DECL
+ && TREE_CODE (ctx) == FUNCTION_DECL)))
ctx = TYPE_CONTEXT (ctx);
/* Likewise namespaces in case we do not want to emit DIEs for them. */
if (debug_info_level <= DINFO_LEVEL_TERSE)
if that works it's OK. Can you run it on the gdb testsuite with -flto added
as well please (you need to do before/after comparison since IIRC adding
-flto will add a few fails).
Thanks,
Richard.
