On 19/07/2021 11:45, Richard Biener wrote:
> 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)
>
This causes an ICE,
internal compiler error: tree check: expected class 'type', have 'declaration'
(function_decl)
Did you intend something like this:
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 561f8b23517..c61f0041fba 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -6121,3 +6121,8 @@ maybe_create_die_with_external_ref (tree decl)
- /* Peel types in the context stack. */
- while (ctx && TYPE_P (ctx))
- ctx = TYPE_CONTEXT (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_P (ctx) ? TYPE_CONTEXT (ctx) : DECL_CONTEXT (ctx);
+
> 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.
>
--
Hafiz Abid Qadeer
Mentor, a Siemens Business
