Re: [PATCH] debug: Pass --gdwarf-N to assembler if fixed gas is detected during configure
Hi, On Tue, 2020-10-06 at 16:57 -0400, Jason Merrill wrote: > All three of these patches (Jakub's, and your two) look good to me, > except that your add_filepath_AT_string patch is missing comments on > some of the new functions. I added documentation for the two new functions missing comments before pushing. Thanks, Mark
Re: [PATCH] debug: Pass --gdwarf-N to assembler if fixed gas is detected during configure
On 10/6/20 11:54 AM, Mark Wielaard wrote:
Hi,
On Fri, 2020-09-18 at 17:21 +0200, Mark Wielaard wrote:
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
* 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?
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.
On top of that, we also need the following, which makes sure the actual
compilation directory is used in a DWARF5 .debug_line directory table
(and not just a relative path).
All three of these patches (Jakub's, and your two) look good to me,
except that your add_filepath_AT_string patch is missing comments on
some of the new functions.
Jason
Re: [PATCH] debug: Pass --gdwarf-N to assembler if fixed gas is detected during configure
Hi,
On Fri, 2020-09-18 at 17:21 +0200, Mark Wielaard wrote:
> 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
> >
> > * 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?
>
> 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.
On top of that, we also need the following, which makes sure the actual
compilation directory is used in a DWARF5 .debug_line directory table
(and not just a relative path).
From 66b25bc0a5df06e211b48a54e3b5d33999c24fb6 Mon Sep 17 00:00:00 2001
From: Mark Wielaard
Date: Tue, 6 Oct 2020 17:41:19 +0200
Subject: [PATCH] debug: Make sure to output .file 0 when generating DWARF5.
When gas outputs DWARF5 .debug_line[_str] then we have to tell it the
comp_dir and main file name for the zero entry line table. Otherwise
gas has to guess at the CU compilation directory and file.
Before a gcc -gdwarf-5 ../src/hello.c line table looked like:
Directory table:
0 ../src (24)
1 ../src (24)
2 /usr/include (31)
File name table:
0 hello.c (16), 0
1 hello.c (16), 1
2 stdio.h (44), 2
With this patch it looks like:
Directory table:
0 /tmp/obj (0)
1 ../src (24)
2 /usr/include (31)
File name table:
0 ../src/hello.c (9), 0
1 hello.c (16), 1
2 stdio.h (44), 2
gcc/ChangeLog:
* dwarf2out.c (dwarf2out_finish): Emit .file 0 entry when
generating DWARF5 .debug_line table through gas.
---
gcc/dwarf2out.c | 21 +
1 file changed, 21 insertions(+)
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index a43082864a75..399937a9f310 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -31764,6 +31764,27 @@ dwarf2out_finish (const char *filename)
ASM_OUTPUT_LABEL (asm_out_file, debug_line_section_label);
if (! output_asm_line_debug_info ())
output_line_info (false);
+ else if (asm_outputs_debug_line_str ())
+{
+ /* When gas outputs DWARF5 .debug_line[_str] then we have to
+ tell it the comp_dir and main file name for the zero entry
+ line table. */
+ const char *comp_dir, *filename0;
+
+ comp_dir = comp_dir_string ();
+ if (comp_dir == NULL)
+ comp_dir = "";
+
+ filename0 = get_AT_string (comp_unit_die (), DW_AT_name);
+ if (filename0 == NULL)
+ filename0 = "";
+
+ fprintf (asm_out_file, "\t.file 0 ");
+ output_quoted_string (asm_out_file, remap_debug_filename (comp_dir));
+ fputc (' ', asm_out_file);
+ output_quoted_string (asm_out_file, remap_debug_filename (filename0));
+ fputc ('\n', asm_out_file);
+}
if (dwarf_split_debug_info && info_section_emitted)
{
--
2.18.4
Re: [PATCH] debug: Pass --gdwarf-N to assembler if fixed gas is detected during configure
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
>
> * 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
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::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, );
+}
+}
+
/* 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
Re: [PATCH] debug: Pass --gdwarf-N to assembler if fixed gas is detected during configure
On Wed, Sep 16, 2020 at 02:33:03PM +0200, Mark Wielaard wrote:
> > 2020-09-15 Jakub Jelinek
> >
> > * 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.
>
> I tested against the binutils-2_35-branch which will become 2.35.1 next
> week. The configure tests succeed there. So I think you can change the
> [elf,2,36,0] to [elf,2,35,1].
No problem with such a change, although it isn't that important, because
most of the people don't use in-tree builds and for out of tree builds
the actual test rather than version comparison is used instead.
Jakub
Re: [PATCH] debug: Pass --gdwarf-N to assembler if fixed gas is detected during configure
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
>
> * 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.
I tested against the binutils-2_35-branch which will become 2.35.1 next
week. The configure tests succeed there. So I think you can change the
[elf,2,36,0] to [elf,2,35,1].
Also tested that they fail with an older binutils (2.32).
Cheers,
Mark
[PATCH] debug: Pass --gdwarf-N to assembler if fixed gas is detected during configure
On Thu, Sep 10, 2020 at 01:45:50PM +0200, Jakub Jelinek wrote:
> On Thu, Sep 10, 2020 at 01:16:57PM +0200, Jakub Jelinek via Gcc-patches wrote:
> > As for the test assembly, I'd say we should take
> > #define F void foo (void) {}
> > F
> > compile it with
> > gcc -S -O2 -g1 -dA -gno-as-loc-support -fno-merge-debug-strings
> > remove .cfi_* directives, remove the ret instruction, change @function
> > and @progbits to %function and %progbits, change .uleb128 to just .byte,
> > I think all the values should be small enough, maybe change .value to
> > .2byte and .long to .4byte (whatever is most portable across different
> > arches and gas versions), simplify (shorten) strings and adjust
> > sizes, and do something with the .quad directives, that is dependent on
> > the address size, perhaps just take those attributes out and adjust
> > .debug_abbrev? Finally, remove all comments (emit them in the first case
> > just to better understand the debug info).
>
> I'm afraid it is hard to avoid the .quad or .8byte.
> Here is a 64-bit address version that assembles fine by both x86_64 and
> aarch64 as.
> Unfortunately doesn't fail with broken gas versions with -gdwarf-2 without
> the nop, so we'll need at least a nop in there.
> Fortunately gcc/configure.ac already determines the right nop insn for the
> target, in $insn.
> So I guess what we want next is have the 32-bit version of this with .4byte
> instead of .8byte and just let's try to assemble both versions, first
> without -gdwarf-2 and the one that succeeds assemble again with -gdwarf-2
> and check for the duplicate .debug_line sections error.
> What do you think?
Ok, here it is in patch form.
I've briefly tested it, with the older binutils I have around (no --gdwarf-N
support), with latest gas (--gdwarf-N that can be passed to as even when
compiling C/C++ etc. code and emitting .debug_line) and latest gas with Mark's
fix
reverted (--gdwarf-N support, but can only pass it to as when assembling
user .s/.S files, not when compiling C/C++ etc.).
Will bootstrap/regtest (with the older binutils) later tonight.
2020-09-15 Jakub Jelinek
* configure.ac (HAVE_AS_GDWARF_5_DEBUG_FLAG,
HAVE_AS_WORKING_DWARF_4_FLAG): New tests.
* gcc.c (ASM_DEBUG_DWARF_OPTION): Define.
(ASM_DEBUG_SPEC): Use ASM_DEBUG_DWARF_OPTION instead of
"--gdwarf2". Use %{cond:opt1;:opt2} style.
(ASM_DEBUG_OPTION_DWARF_OPT): Define.
(ASM_DEBUG_OPTION_SPEC): Define.
(asm_debug_option): New variable.
(asm_options): Add "%(asm_debug_option)".
(static_specs): Add asm_debug_option entry.
(static_spec_functions): Add dwarf-version-gt.
(debug_level_greater_than_spec_func): New function.
* config/darwin.h (ASM_DEBUG_OPTION_SPEC): Define.
* config/darwin9.h (ASM_DEBUG_OPTION_SPEC): Redefine.
* config.in: Regenerated.
* configure: Regenerated.
--- gcc/configure.ac.jj 2020-09-08 16:48:32.377900856 +0200
+++ gcc/configure.ac2020-09-15 18:07:23.292249972 +0200
@@ -5192,6 +5192,194 @@ if test x"$insn" != x; then
[AC_DEFINE(HAVE_AS_GDWARF2_DEBUG_FLAG, 1,
[Define if your assembler supports the --gdwarf2 option.])])
+ gcc_GAS_CHECK_FEATURE([--gdwarf-5 option],
+ gcc_cv_as_gdwarf_5_flag,
+ [elf,2,36,0], [--gdwarf-5], [$insn],,
+ [AC_DEFINE(HAVE_AS_GDWARF_5_DEBUG_FLAG, 1,
+[Define if your assembler supports the --gdwarf-5 option.])])
+
+ dwarf4_debug_info_size=0x46
+ dwarf4_high_pc_form=7
+ dwarf4_debug_aranges_size=0x2c
+ dwarf4_line_sz=9
+ for dwarf4_addr_size in 8 4; do
+ conftest_s="\
+ .file \"a.c\"
+ .text
+.Ltext0:
+ .p2align 4
+ .globl foo
+ .type foo, %function
+foo:
+.LFB0:
+.LM1:
+ $insn
+.LM2:
+.LFE0:
+ .size foo, .-foo
+.Letext0:
+ .section.debug_info,\"\",%progbits
+.Ldebug_info0:
+ .4byte $dwarf4_debug_info_size
+ .2byte 0x4
+ .4byte .Ldebug_abbrev0
+ .byte 0x$dwarf4_addr_size
+ .byte 0x1
+ .ascii \"GNU C17\\0\"
+ .byte 0xc
+ .ascii \"a.c\\0\"
+ .ascii \"/\\0\"
+ .${dwarf4_addr_size}byte.Ltext0
+ .${dwarf4_addr_size}byte.Letext0-.Ltext0
+ .4byte .Ldebug_line0
+ .byte 0x2
+ .ascii \"foo\\0\"
+ .byte 0x1
+ .byte 0x2
+ .byte 0x1
+ .${dwarf4_addr_size}byte.LFB0
+ .${dwarf4_addr_size}byte.LFE0-.LFB0
+ .byte 0x1
+ .byte 0x9c
+ .byte 0
+ .section.debug_abbrev,\"\",%progbits
+.Ldebug_abbrev0:
+ .byte 0x1
+ .byte 0x11
+ .byte 0x1
+ .byte 0x25
+ .byte 0x8
+ .byte 0x13
+ .byte 0xb
+ .byte 0x3
+ .byte 0x8
+ .byte 0x1b
+ .byte 0x8
+ .byte 0x11
+ .byte 0x1
+ .byte 0x12
+ .byte 0x$dwarf4_high_pc_form
+ .byte 0x10
+ .byte 0x17
+ .byte 0
+ .byte 0
+ .byte
