A patch from Honza not LTO streaming DECL_ORIGINAL_TYPE ends up
ICEing during LTO bootstrap because we end up not re-using the
DIE we create late during LTRANS for a subprogram because its
parent is a namespace rather than a CU DIE (or a module).
I'm wondering of the general reason why we enforce (inconsistently)
"We always want the DIE for this function that has the *_pc attributes to
be under comp_unit_die so the debugger can find it."
We indeed generate a specification DIE rooted at the CU in addition to the
declaration DIE inside the namespace for sth as simple as
namespace Foo { void foo () {} }
anyhow - the comment also says "We also need to do this [re-use the DIE]
for abstract instances of inlines, since the spec requires the out-of-line
copy to have the same parent.". Not sure what condition this part of
the comment applies to.
So my fix is to move the || get_AT (old_die, DW_AT_abstract_origin)
check I added for early LTO debug to a global override - forcing
DIE re-use for any DIE with an abstract origin set. That is, all
concrete instances are fine where they are. That also avoids
double-indirection DW_AT_specification -> DW_AT_abstract_origin -> DIE.
But as said, I wonder about the overall condition, esp. the
DW_TAG_module special-casing (but not at the same time
special-casing DW_TAG_namespace or DW_TAG_partial_unit).
LTO bootstrap is in progress on x86_64-unknown-linux-gnu.
OK if that succeeds?
Thanks,
Richard.
2018-06-26 Richard Biener <rguent...@suse.de>
* dwarf2out.c (gen_subprogram_die): Always re-use DIEs with an
DW_AT_abstract_origin attribute.
Index: gcc/dwarf2out.c
===================================================================
--- gcc/dwarf2out.c (revision 262132)
+++ gcc/dwarf2out.c (working copy)
@@ -22780,26 +22780,25 @@ gen_subprogram_die (tree decl, dw_die_re
apply; we just use the old DIE. */
expanded_location s = expand_location (DECL_SOURCE_LOCATION (decl));
struct dwarf_file_data * file_index = lookup_filename (s.file);
- if ((is_cu_die (old_die->die_parent)
- /* This condition fixes the inconsistency/ICE with the
- following Fortran test (or some derivative thereof) while
- building libgfortran:
+ if (((is_cu_die (old_die->die_parent)
+ /* This condition fixes the inconsistency/ICE with the
+ following Fortran test (or some derivative thereof) while
+ building libgfortran:
- module some_m
- contains
- logical function funky (FLAG)
- funky = .true.
- end function
- end module
- */
- || (old_die->die_parent
- && old_die->die_parent->die_tag == DW_TAG_module)
- || context_die == NULL)
+ module some_m
+ contains
+ logical function funky (FLAG)
+ funky = .true.
+ end function
+ end module
+ */
+ || (old_die->die_parent
+ && old_die->die_parent->die_tag == DW_TAG_module)
+ || context_die == NULL)
&& (DECL_ARTIFICIAL (decl)
/* The location attributes may be in the abstract origin
which in the case of LTO might be not available to
look at. */
- || get_AT (old_die, DW_AT_abstract_origin)
|| (get_AT_file (old_die, DW_AT_decl_file) == file_index
&& (get_AT_unsigned (old_die, DW_AT_decl_line)
== (unsigned) s.line)
@@ -22807,6 +22806,10 @@ gen_subprogram_die (tree decl, dw_die_re
|| s.column == 0
|| (get_AT_unsigned (old_die, DW_AT_decl_column)
== (unsigned) s.column)))))
+ /* With LTO if there's an abstract instance for
+ the old DIE, this is a concrete instance and
+ thus re-use the DIE. */
+ || get_AT (old_die, DW_AT_abstract_origin))
{
subr_die = old_die;
