Hi,
On Tue, 2020-09-15 at 20:40 +0200, Jakub Jelinek wrote:
> Ok, here it is in patch form.
> I've briefly tested it, with the older binutils I have around (no --gdwarf-N
> support), with latest gas (--gdwarf-N that can be passed to as even when
> compiling C/C++ etc. code and emitting .debug_line) and latest gas with
> Mark's fix
> reverted (--gdwarf-N support, but can only pass it to as when assembling
> user .s/.S files, not when compiling C/C++ etc.).
> Will bootstrap/regtest (with the older binutils) later tonight.
>
> 2020-09-15 Jakub Jelinek <ja...@redhat.com>
>
> * configure.ac (HAVE_AS_GDWARF_5_DEBUG_FLAG,
> HAVE_AS_WORKING_DWARF_4_FLAG): New tests.
> * gcc.c (ASM_DEBUG_DWARF_OPTION): Define.
> (ASM_DEBUG_SPEC): Use ASM_DEBUG_DWARF_OPTION instead of
> "--gdwarf2". Use %{cond:opt1;:opt2} style.
> (ASM_DEBUG_OPTION_DWARF_OPT): Define.
> (ASM_DEBUG_OPTION_SPEC): Define.
> (asm_debug_option): New variable.
> (asm_options): Add "%(asm_debug_option)".
> (static_specs): Add asm_debug_option entry.
> (static_spec_functions): Add dwarf-version-gt.
> (debug_level_greater_than_spec_func): New function.
> * config/darwin.h (ASM_DEBUG_OPTION_SPEC): Define.
> * config/darwin9.h (ASM_DEBUG_OPTION_SPEC): Redefine.
> * config.in: Regenerated.
> * configure: Regenerated.
Once this is in we can more generally emit DW_FORM_line_str for
filepaths in CU DIEs for the name and comp_dir attribute. There
currently is a bit of a hack to do this in dwarf2out_early_finish, but
that only works when the assembler doesn't emit a DWARF5 .debug_line,
but gcc does it itself.
What do you think of the attached patch?
From c31667db57de62c3107a0b2a5e30fbd57a4708a3 Mon Sep 17 00:00:00 2001
From: Mark Wielaard <m...@klomp.org>
Date: Fri, 18 Sep 2020 17:07:03 +0200
Subject: [PATCH] Output filepath strings in .debug_line_str for DWARF5
DWARF5 has a new string table specially for file paths. .debug_line
file and dir tables reference strings in .debug_line_str. If a
.debug_line_str section is emitted then also place CU DIE file
names and comp dirs there.
gcc/ChangeLog:
* dwarf2out.c (add_filepath_AT_string): New function.
(asm_outputs_debug_line_str): Likewise.
(add_filename_attribute): Likewise.
(add_comp_dir_attribute): Call add_filepath_AT_string.
(gen_compile_unit_die): Call add_filename_attribute for name.
(init_sections_and_labels): Init debug_line_str_section when
asm_outputs_debug_line_str return true.
(dwarf2out_early_finish): Remove DW_AT_name and DW_AT_comp_dir
hack and call add_filename_attribute for the remap_debug_filename.
---
gcc/dwarf2out.c | 96 ++++++++++++++++++++++++++++++++-----------------
1 file changed, 64 insertions(+), 32 deletions(-)
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 4096c0c0d69f..a43082864a75 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -3347,6 +3347,8 @@ output_asm_line_debug_info (void)
|| !debug_variable_location_views));
}
+static bool asm_outputs_debug_line_str (void);
+
/* Minimum line offset in a special line info. opcode.
This value was chosen to give a reasonable range of values. */
#define DWARF_LINE_BASE -10
@@ -4731,6 +4733,33 @@ reset_indirect_string (indirect_string_node **h, void *)
return 1;
}
+static inline void
+add_filepath_AT_string (dw_die_ref die, enum dwarf_attribute attr_kind,
+ const char *str)
+{
+ if (! asm_outputs_debug_line_str ())
+ add_AT_string (die, attr_kind, str);
+ else
+ {
+ dw_attr_node attr;
+ struct indirect_string_node *node;
+
+ if (!debug_line_str_hash)
+ debug_line_str_hash
+ = hash_table<indirect_string_hasher>::create_ggc (10);
+
+ node = find_AT_string_in_table (str, debug_line_str_hash);
+ set_indirect_string (node);
+ node->form = DW_FORM_line_strp;
+
+ attr.dw_attr = attr_kind;
+ attr.dw_attr_val.val_class = dw_val_class_str;
+ attr.dw_attr_val.val_entry = NULL;
+ attr.dw_attr_val.v.val_str = node;
+ add_dwarf_attr (die, &attr);
+ }
+}
+
/* Find out whether a string should be output inline in DIE
or out-of-line in .debug_str section. */
@@ -11839,6 +11868,29 @@ output_ranges (void)
for -gsplit-dwarf we should use DW_FORM_strx instead. */ \
&& !dwarf_split_debug_info)
+
+/* Returns TRUE if we are outputting DWARF5 and the assembler supports
+ DWARF5 .debug_line tables using .debug_line_str or we generate
+ it ourselves, except for split-dwarf which doesn't have a
+ .debug_line_str. */
+static bool
+asm_outputs_debug_line_str (void)
+{
+ if (dwarf_version >= 5
+ && ! output_asm_line_debug_info ()
+ && DWARF5_USE_DEBUG_LINE_STR)
+ return true;
+ else
+ {
+#if defined(HAVE_AS_GDWARF_5_DEBUG_FLAG) && defined(HAVE_AS_WORKING_DWARF_4_FLAG)
+ return !dwarf_split_debug_info && dwarf_version >= 5;
+#else
+ return false;
+#endif
+ }
+}
+
+
/* Assign .debug_rnglists indexes. */
static void
@@ -20514,6 +20566,13 @@ add_name_attribute (dw_die_ref die, const char *name_string)
}
}
+static void
+add_filename_attribute (dw_die_ref die, const char *name_string)
+{
+ if (name_string != NULL && *name_string != 0)
+ add_filepath_AT_string (die, DW_AT_name, name_string);
+}
+
/* Generate a DW_AT_description attribute given some string value to be included
as the value of the attribute. */
@@ -20640,7 +20699,7 @@ add_comp_dir_attribute (dw_die_ref die)
{
const char * wd = comp_dir_string ();
if (wd != NULL)
- add_AT_string (die, DW_AT_comp_dir, wd);
+ add_filepath_AT_string (die, DW_AT_comp_dir, wd);
}
/* Given a tree node VALUE describing a scalar attribute ATTR (i.e. a bound, a
@@ -24482,7 +24541,7 @@ gen_compile_unit_die (const char *filename)
if (filename)
{
- add_name_attribute (die, filename);
+ add_filename_attribute (die, filename);
/* Don't add cwd for <built-in>. */
if (filename[0] != '<')
add_comp_dir_attribute (die);
@@ -28733,7 +28792,8 @@ init_sections_and_labels (bool early_lto_debug)
SECTION_DEBUG, NULL);
debug_str_section = get_section (DEBUG_STR_SECTION,
DEBUG_STR_SECTION_FLAGS, NULL);
- if (!dwarf_split_debug_info && !output_asm_line_debug_info ())
+ if ((!dwarf_split_debug_info && !output_asm_line_debug_info ())
+ || asm_outputs_debug_line_str ())
debug_line_str_section = get_section (DEBUG_LINE_STR_SECTION,
DEBUG_STR_SECTION_FLAGS, NULL);
@@ -32020,37 +32080,9 @@ dwarf2out_early_finish (const char *filename)
/* Add the name for the main input file now. We delayed this from
dwarf2out_init to avoid complications with PCH. */
- add_name_attribute (comp_unit_die (), remap_debug_filename (filename));
+ add_filename_attribute (comp_unit_die (), remap_debug_filename (filename));
add_comp_dir_attribute (comp_unit_die ());
- /* When emitting DWARF5 .debug_line_str, move DW_AT_name and
- DW_AT_comp_dir into .debug_line_str section. */
- if (!output_asm_line_debug_info ()
- && dwarf_version >= 5
- && DWARF5_USE_DEBUG_LINE_STR)
- {
- for (int i = 0; i < 2; i++)
- {
- dw_attr_node *a = get_AT (comp_unit_die (),
- i ? DW_AT_comp_dir : DW_AT_name);
- if (a == NULL
- || AT_class (a) != dw_val_class_str
- || strlen (AT_string (a)) + 1 <= DWARF_OFFSET_SIZE)
- continue;
-
- if (! debug_line_str_hash)
- debug_line_str_hash
- = hash_table<indirect_string_hasher>::create_ggc (10);
-
- struct indirect_string_node *node
- = find_AT_string_in_table (AT_string (a), debug_line_str_hash);
- set_indirect_string (node);
- node->form = DW_FORM_line_strp;
- a->dw_attr_val.v.val_str->refcount--;
- a->dw_attr_val.v.val_str = node;
- }
- }
-
/* With LTO early dwarf was really finished at compile-time, so make
sure to adjust the phase after annotating the LTRANS CU DIE. */
if (in_lto_p)
--
2.18.4
