On Wed, 2024-11-27 at 15:18:39 +0000, Richard Biener wrote:
> I'm not sure it will work this way together with the output_die hunk,
> instead
> assemblers likely expect all this to happen close to the actual label
> emission, so I suggest to only split out the visibiltiy/globalizing fancy
> and emit it from output_die instead.
Thanks, apparently somehow I got the idea that the
globalization/weakening of symbols has to be together.
Which seems to be not needed, so I moved everything to output_die next
to label emission.
Michal
-----------------------------------------------
Die symbols are used for external references.
Typically during LTO, early debug emits 'die_symbol+offset' for each
possibly referenced DIE in future. Partitions in LTRANS phase then
use these references.
Originally die symbols are handled only in root comp_unit and
in attributes.
This patch allows die symbols to be attached to any DIE.
References then choose closest parent with die symbol.
gcc/ChangeLog:
* dwarf2out.cc (dwarf2out_die_ref_for_decl):
Choose closest parent with die_symbol.
(output_die): Output asm label.
(output_comp_unit): Output die_symbol list.
(reset_dies): Reset all die_symbols.
(dwarf2out_finish): Don't reset comp_unit die_symbol.
---
gcc/dwarf2out.cc | 69 +++++++++++++++++++++++-------------------------
1 file changed, 33 insertions(+), 36 deletions(-)
diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index 6bb73c6e5c6..1e55b900712 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -6039,14 +6039,14 @@ dwarf2out_die_ref_for_decl (tree decl, const char **sym,
/* Similar to get_ref_die_offset_label, but using the "correct"
label. */
- *off = die->die_offset;
- while (die->die_parent)
+ unsigned HOST_WIDE_INT unit_offset = die->die_offset;
+ while (die->die_parent && (die->comdat_type_p || !die->die_id.die_symbol))
die = die->die_parent;
- /* For the containing CU DIE we compute a die_symbol in
+ /* Root CU DIE always contains die_symbol computed in
compute_comp_unit_symbol. */
- if (die->die_tag == DW_TAG_compile_unit)
+ if (!die->comdat_type_p && die->die_id.die_symbol)
{
- gcc_assert (die->die_id.die_symbol != NULL);
+ *off = unit_offset - die->die_offset;
*sym = die->die_id.die_symbol;
return true;
}
@@ -10798,6 +10798,29 @@ output_die (dw_die_ref die)
unsigned long size;
unsigned ix;
+ /* Output die_symbol. */
+ if ((flag_generate_lto || flag_generate_offload)
+ && !die->comdat_type_p && die->die_id.die_symbol)
+ {
+ const char* sym = die->die_id.die_symbol;
+ /*tree decl = build_decl (UNKNOWN_LOCATION, VAR_DECL,
+ get_identifier (sym), char_type_node);
+ TREE_PUBLIC (decl) = true;
+ TREE_STATIC (decl) = true;
+ DECL_ARTIFICIAL (decl) = true;
+ DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
+ DECL_VISIBILITY_SPECIFIED (decl) = true;
+ targetm.asm_out.assemble_visibility (decl, VISIBILITY_HIDDEN);*/
+#ifdef ASM_WEAKEN_LABEL
+ /* We prefer a .weak because that handles duplicates from duplicate
+ archive members in a graceful way. */
+ ASM_WEAKEN_LABEL (asm_out_file, sym);
+#else
+ targetm.asm_out.globalize_label (asm_out_file, sym);
+#endif
+ ASM_OUTPUT_LABEL (asm_out_file, sym);
+ }
+
dw2_asm_output_data_uleb128 (die->die_abbrev, "(DIE (%#lx) %s)",
(unsigned long)die->die_offset,
dwarf_tag_name (die->die_tag));
@@ -11234,8 +11257,6 @@ static void
output_comp_unit (dw_die_ref die, int output_if_empty,
const unsigned char *dwo_id)
{
- const char *oldsym;
-
/* Unless we are outputting main CU, we may throw away empty ones. */
if (!output_if_empty && die->die_child == NULL)
return;
@@ -11267,35 +11288,10 @@ output_comp_unit (dw_die_ref die, int output_if_empty,
: DWARF_COMPILE_UNIT_HEADER_SIZE);
calc_die_sizes (die);
- oldsym = die->die_id.die_symbol;
-
switch_to_section (debug_info_section);
ASM_OUTPUT_LABEL (asm_out_file, debug_info_section_label);
info_section_emitted = true;
- /* For LTO cross unit DIE refs we want a symbol on the start of the
- debuginfo section, not on the CU DIE. */
- if ((flag_generate_lto || flag_generate_offload) && oldsym)
- {
- /* ??? No way to get visibility assembled without a decl. */
- tree decl = build_decl (UNKNOWN_LOCATION, VAR_DECL,
- get_identifier (oldsym), char_type_node);
- TREE_PUBLIC (decl) = true;
- TREE_STATIC (decl) = true;
- DECL_ARTIFICIAL (decl) = true;
- DECL_VISIBILITY (decl) = VISIBILITY_HIDDEN;
- DECL_VISIBILITY_SPECIFIED (decl) = true;
- targetm.asm_out.assemble_visibility (decl, VISIBILITY_HIDDEN);
-#ifdef ASM_WEAKEN_LABEL
- /* We prefer a .weak because that handles duplicates from duplicate
- archive members in a graceful way. */
- ASM_WEAKEN_LABEL (asm_out_file, oldsym);
-#else
- targetm.asm_out.globalize_label (asm_out_file, oldsym);
-#endif
- ASM_OUTPUT_LABEL (asm_out_file, oldsym);
- }
-
/* Output debugging information. */
output_compilation_unit_header (dwo_id
? DW_UT_split_compile : DW_UT_compile);
@@ -11309,7 +11305,7 @@ output_comp_unit (dw_die_ref die, int output_if_empty,
/* Leave the marks on the main CU, so we can check them in
output_pubnames. */
- if (oldsym)
+ if (die->die_id.die_symbol)
unmark_dies (die);
}
@@ -32313,6 +32309,10 @@ reset_dies (dw_die_ref die)
die->die_abbrev = 0;
remove_AT (die, DW_AT_sibling);
+ /* Reset die symbols so we don't output them twice. */
+ if (!die->comdat_type_p)
+ die->die_id.die_symbol = NULL;
+
FOR_EACH_CHILD (die, c, reset_dies (c));
}
@@ -32404,9 +32404,6 @@ dwarf2out_finish (const char *filename)
reset_dies (ctnode->root_die);
}
- /* Reset die CU symbol so we don't output it twice. */
- comp_unit_die ()->die_id.die_symbol = NULL;
-
/* Remove DW_AT_macro and DW_AT_stmt_list from the early output. */
remove_AT (comp_unit_die (), DW_AT_stmt_list);
if (have_macinfo)
--
2.47.0
