[PATCH] Binutils support for split-dwarf and dwarf-5
Kumar N, Bhuvanendra
Bhuvanendra.KumarN@amd.com
Thu Jun 2 14:55:51 GMT 2022
[Public]
Hi,
Binutils support for split-dwarf and dwarf5 is now added for gcc and clang. There are 2 patches. Basic sections dump like .debug_info.dwo, .debug_abbrev.dwo, .debug_str.dwo etc are supported in patch 1/2. location list and ranges list sections dump with split-dwarf and dwarf5 are supported in patch 2/2 and patch 2/2 is continuation of patch 1/2. Both the patches are attached and also inlined below. Separating these issues as individual patches might be easy to review, hence 2 patches are there.
Issues fixed in patch 1/2 :
There are few differences b/w dwarf4 and dwarf5 as shared below, w.r.t. split-dwarf support added like different attributes/forms used to represent DWO name and ID, .debug_str_offsets section etc. All these are addressed. I have tested these changes with gcc and clang compiled objects with split-dwarf and dwarf-5.
DWARF4:
* DW_AT_GNU_dwo_name [DW_FORM_strp]
* DW_AT_GNU_dwo_id [DW_FORM_data8]
* Above attribute are part of DW_TAG_compile_unit
DWARF5:
* DW_AT_dwo_name [DW_FORM_strp]
* Above attribute is part of DW_TAG_skeleton_unit
* .debug_str_offsets is used to refer to .debug_str section
NOTE: DWO ID is not printed for dwarf 5 during initial dwo file dump information summary. But its dumped under .debug_info section dump. Because now there is no separate attribute in dwarf5 for DWO ID like it was there in dwarf4(DW_AT_GNU_dwo_id).
Issues fixed in patch 2/2 :
.debug_loclists.dwo and .debug_rnglists.dwo section dumps are taken care. I have tested these changes for clang compiled objects with split-dwarf and dwarf-5, where .debug_loclists.dwo and .debug_rnglists.dwo sections exist in the separate debug file (.dwo files)
Regards,
bhuvan
Patch 1/2 inlined:
>From 1bda1e144f43d1f41fe30a934ba008561083dc07 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=9Cbhkumarn=E2=80=9D?= Bhuvanendra.KumarN@amd.com<mailto:Bhuvanendra.KumarN@amd.com>
Date: Thu, 2 Jun 2022 17:44:02 +0530
Subject: [PATCH] [PATCH 1/2] Binutils support for split-dwarf and dwarf-5.
This fix adds support for split-dwarf and dwarf5, for both gcc and clang.
There are 2 patches. Basic sections dump like .debug_info.dwo,
.debug_abbrev.dwo, .debug_str.dwo etc are supported in this patch 1/2.
But location list and ranges list sections dump with split-dwarf and dwarf5
are supported in the next patch 2/2.
There are few differences b/w dwarf4 and dwarf5, w.r.t. split-dwarf support
added like different attributes/forms used to represent DWO name and ID,
.debug_str_offsets section etc. All these are addressed.
* dwarf.c (fetch_indexed_string): Use str_offsets_base to calculate
the string offset.
(read_and_display_attr_value): Set str_offsets_base i.e. string offset
table base address.
(process_debug_info): Include DW_TAG_skeleton_unit.
(load_separate_debug_files): Load .debug_str_offsets if exists.
Skip DWO ID dump for dwarf-5.
* testsuite/binutils-all/readelf.exp: Added new test point.
* testsuite/binutils-all/readelf.k5: New file.
* testsuite/binutils-all/dwo_5.s: New file.
---
binutils/dwarf.c | 11 +-
binutils/testsuite/binutils-all/dwo_5.s | 257 ++++++++++++++++++++
binutils/testsuite/binutils-all/readelf.exp | 12 +
binutils/testsuite/binutils-all/readelf.k5 | 7 +
4 files changed, 285 insertions(+), 2 deletions(-)
create mode 100644 binutils/testsuite/binutils-all/dwo_5.s
create mode 100644 binutils/testsuite/binutils-all/readelf.k5
diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index caa3ce48d00..e8f0ea4cf0c 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -118,6 +118,8 @@ int dwarf_cutoff_level = -1;
unsigned long dwarf_start_die;
int dwarf_check = 0;
+static dwarf_vma str_offsets_base = 0;
+#define DEBUG_STR_OFFSETS_HEADER_LEN 8
/* Convenient constant, to avoid having to cast -1 to dwarf_vma when
testing whether e.g. a locview list is present. */
@@ -779,7 +781,7 @@ fetch_indexed_string (dwarf_vma idx, struct cu_tu_set *this_set,
return _("<index offset is too big>");
}
- str_offset = byte_get (curr + index_offset, offset_size);
+ str_offset = byte_get (curr + index_offset + str_offsets_base, offset_size);
str_offset -= str_section->address;
if (str_offset >= str_section->size)
{
@@ -2485,6 +2487,8 @@ read_and_display_attr_value (unsigned long attribute,
case DW_FORM_GNU_ref_alt:
case DW_FORM_GNU_strp_alt:
SAFE_BYTE_GET_AND_INC (uvalue, data, offset_size, end);
+ if (attribute == DW_AT_str_offsets_base)
+ str_offsets_base = uvalue - DEBUG_STR_OFFSETS_HEADER_LEN;
break;
case DW_FORM_flag_present:
@@ -4016,6 +4020,7 @@ process_debug_info (struct dwarf_section * section,
need_base_address = 0;
break;
case DW_TAG_compile_unit:
+ case DW_TAG_skeleton_unit:
need_base_address = 1;
need_dwo_info = do_loc;
break;
@@ -4059,6 +4064,7 @@ process_debug_info (struct dwarf_section * section,
level);
}
+ str_offsets_base = 0;
/* If a locview attribute appears before a location one,
make sure we don't associate it with an earlier
loclist. */
@@ -11889,6 +11895,7 @@ load_separate_debug_files (void * file, const char * filename)
&& load_debug_section (abbrev, file)
&& load_debug_section (info, file))
{
+ load_debug_section (str_index, file);
free_dwo_info ();
if (process_debug_info (& debug_displays[info].section, file, abbrev,
@@ -11948,7 +11955,7 @@ load_separate_debug_files (void * file, const char * filename)
printf (_(" Directory: %s\n"), dir ? dir : _("<not-found>"));
if (id != NULL)
display_data (printf (_(" ID: ")), (unsigned char *) id, 8);
- else
+ else if (debug_information[0].dwarf_version != 5)
printf (_(" ID: <not specified>\n"));
printf ("\n\n");
}
diff --git a/binutils/testsuite/binutils-all/dwo_5.s b/binutils/testsuite/binutils-all/dwo_5.s
new file mode 100644
index 00000000000..e394467c2be
--- /dev/null
+++ b/binutils/testsuite/binutils-all/dwo_5.s
@@ -0,0 +1,257 @@
+ .file "a.c"
+ .text
+.Ltext0:
+ .globl a
+ .type a, @function
+a:
+.LFB0:
+ .file 1 "a.c"
+ .loc 1 1 13
+ .cfi_startproc
+ pushq %rbp
+ .cfi_def_cfa_offset 16
+ .cfi_offset 6, -16
+ movq %rsp, %rbp
+ .cfi_def_cfa_register 6
+ .loc 1 1 22
+ movl $111, %eax
+ .loc 1 1 1
+ popq %rbp
+ .cfi_def_cfa 7, 8
+ ret
+ .cfi_endproc
+.LFE0:
+ .size a, .-a
+.Letext0:
+ .section .debug_addr,"",@progbits
+ .long 0xc
+ .value 0x5
+ .byte 0x8
+ .byte 0
+.Ldebug_addr0:
+ .quad .LFB0
+ .section .debug_info.dwo,"e",@progbits
+.Ldebug_info0:
+ .long 0x35
+ .value 0x5
+ .byte 0x5
+ .byte 0x8
+ .long .Ldebug_abbrev0
+ .byte 0x46
+ .byte 0x1c
+ .byte 0xf1
+ .byte 0xfb
+ .byte 0xe5
+ .byte 0x96
+ .byte 0x7d
+ .byte 0x2b
+ .uleb128 0x1
+ .uleb128 0x1
+ .byte 0x1d
+ .string "a.c"
+ .uleb128 0
+ .uleb128 0x2
+ .string "a"
+ .byte 0x1
+ .byte 0x1
+ .byte 0x5
+ .long 0x31
+ .uleb128 0
+ .quad .LFE0-.LFB0
+ .uleb128 0x1
+ .byte 0x9c
+ .uleb128 0x3
+ .byte 0x4
+ .byte 0x5
+ .string "int"
+ .byte 0
+ .section .debug_info,"",@progbits
+.Lskeleton_debug_info0:
+ .long 0x31
+ .value 0x5
+ .byte 0x4
+ .byte 0x8
+ .long .Lskeleton_debug_abbrev0
+ .byte 0x46
+ .byte 0x1c
+ .byte 0xf1
+ .byte 0xfb
+ .byte 0xe5
+ .byte 0x96
+ .byte 0x7d
+ .byte 0x2b
+ .uleb128 0x1
+ .quad .Ltext0
+ .quad .Letext0-.Ltext0
+ .long .Ldebug_line0
+ .long .LASF0
+ .long .LASF1
+ .long .Ldebug_addr0
+ .section .debug_abbrev,"",@progbits
+.Lskeleton_debug_abbrev0:
+ .uleb128 0x1
+ .uleb128 0x4a
+ .byte 0
+ .uleb128 0x11
+ .uleb128 0x1
+ .uleb128 0x12
+ .uleb128 0x7
+ .uleb128 0x10
+ .uleb128 0x17
+ .uleb128 0x76
+ .uleb128 0xe
+ .uleb128 0x1b
+ .uleb128 0xe
+ .uleb128 0x2134
+ .uleb128 0x19
+ .uleb128 0x73
+ .uleb128 0x17
+ .byte 0
+ .byte 0
+ .byte 0
+ .section .debug_abbrev.dwo,"e",@progbits
+.Ldebug_abbrev0:
+ .uleb128 0x1
+ .uleb128 0x11
+ .byte 0x1
+ .uleb128 0x25
+ .uleb128 0x1a
+ .uleb128 0x13
+ .uleb128 0xb
+ .uleb128 0x3
+ .uleb128 0x8
+ .uleb128 0x1b
+ .uleb128 0x1a
+ .byte 0
+ .byte 0
+ .uleb128 0x2
+ .uleb128 0x2e
+ .byte 0
+ .uleb128 0x3f
+ .uleb128 0x19
+ .uleb128 0x3
+ .uleb128 0x8
+ .uleb128 0x3a
+ .uleb128 0xb
+ .uleb128 0x3b
+ .uleb128 0xb
+ .uleb128 0x39
+ .uleb128 0xb
+ .uleb128 0x27
+ .uleb128 0x19
+ .uleb128 0x49
+ .uleb128 0x13
+ .uleb128 0x11
+ .uleb128 0x1b
+ .uleb128 0x12
+ .uleb128 0x7
+ .uleb128 0x40
+ .uleb128 0x18
+ .uleb128 0x7a
+ .uleb128 0x19
+ .byte 0
+ .byte 0
+ .uleb128 0x3
+ .uleb128 0x24
+ .byte 0
+ .uleb128 0xb
+ .uleb128 0xb
+ .uleb128 0x3e
+ .uleb128 0xb
+ .uleb128 0x3
+ .uleb128 0x8
+ .byte 0
+ .byte 0
+ .byte 0
+ .section .debug_gnu_pubnames,"",@progbits
+ .long 0x15
+ .value 0x2
+ .long .Lskeleton_debug_info0
+ .long 0x39
+ .long 0x1c
+ .byte 0x30
+ .string "a"
+ .long 0
+ .section .debug_gnu_pubtypes,"",@progbits
+ .long 0x17
+ .value 0x2
+ .long .Lskeleton_debug_info0
+ .long 0x39
+ .long 0x31
+ .byte 0x90
+ .string "int"
+ .long 0
+ .section .debug_aranges,"",@progbits
+ .long 0x2c
+ .value 0x2
+ .long .Lskeleton_debug_info0
+ .byte 0x8
+ .byte 0
+ .value 0
+ .value 0
+ .quad .Ltext0
+ .quad .Letext0-.Ltext0
+ .quad 0
+ .quad 0
+ .section .debug_line,"",@progbits
+.Ldebug_line0:
+ .section .debug_line.dwo,"e",@progbits
+.Lskeleton_debug_line0:
+ .long .LELT0-.LSLT0
+.LSLT0:
+ .value 0x5
+ .byte 0x8
+ .byte 0
+ .long .LELTP0-.LASLTP0
+.LASLTP0:
+ .byte 0x1
+ .byte 0x1
+ .byte 0x1
+ .byte 0xf6
+ .byte 0xf2
+ .byte 0xd
+ .byte 0
+ .byte 0x1
+ .byte 0x1
+ .byte 0x1
+ .byte 0x1
+ .byte 0
+ .byte 0
+ .byte 0
+ .byte 0x1
+ .byte 0
+ .byte 0
+ .byte 0x1
+ .byte 0x1
+ .uleb128 0x1
+ .uleb128 0x8
+ .uleb128 0x1
+ .string "/tmp"
+ .byte 0x2
+ .uleb128 0x1
+ .uleb128 0x8
+ .uleb128 0x2
+ .uleb128 0xb
+ .uleb128 0x2
+ .string "a.c"
+ .byte 0
+ .string "a.c"
+ .byte 0
+.LELTP0:
+.LELT0:
+ .section .debug_str,"MS",@progbits,1
+.LASF1:
+ .string "/tmp"
+.LASF0:
+ .string "a.dwo"
+ .section .debug_str_offsets.dwo,"e",@progbits
+ .long 0xc
+ .value 0x5
+ .value 0
+ .long 0
+ .long 0x5
+ .section .debug_str.dwo,"e",@progbits
+ .string "/tmp"
+ .string "GNU C17 10.0.0 20190813 (experimental) -mtune=generic -march=x86-64 -gdwarf-5 -gsplit-dwarf"
+ .ident "GCC: (GNU) 10.0.0 20190813 (experimental)"
+ .section .note.GNU-stack,"",@progbits
diff --git a/binutils/testsuite/binutils-all/readelf.exp b/binutils/testsuite/binutils-all/readelf.exp
index 0f7a1f3b5a0..b68224d5019 100644
--- a/binutils/testsuite/binutils-all/readelf.exp
+++ b/binutils/testsuite/binutils-all/readelf.exp
@@ -572,6 +572,18 @@ if {![binutils_assemble $srcdir/$subdir/dwo.s tmpdir/dwo.o]} then {
readelf_test {--debug-dump=links --debug-dump=no-follow-links} $tempfile readelf.k2
}
+if {![binutils_assemble $srcdir/$subdir/dwo_5.s tmpdir/dwo_5.o]} then {
+ unsupported "readelf --debug-dump=links (failed to assemble dwo_5.s)"
+} else {
+ if ![is_remote host] {
+ set tempfile tmpdir/dwo_5.o
+ } else {
+ set tempfile [remote_download host tmpdir/dwo_5.o]
+ }
+
+ readelf_test {--debug-dump=links --debug-dump=no-follow-links} $tempfile readelf.k5
+}
+
if {![binutils_assemble $srcdir/$subdir/zero-sec.s tmpdir/zero-sec.o]} then {
unsupported "readelf --enable-checks (failed to assemble zero-sec.s)"
} else {
diff --git a/binutils/testsuite/binutils-all/readelf.k5 b/binutils/testsuite/binutils-all/readelf.k5
new file mode 100644
index 00000000000..49779224f2c
--- /dev/null
+++ b/binutils/testsuite/binutils-all/readelf.k5
@@ -0,0 +1,7 @@
+The .debug_info section contains link\(s\) to dwo file\(s\):
+
+ Name: a.dwo
+ Directory: /tmp
+
+
+
--
2.17.1
Patch 2/2 inlined:
>From dab73681a6e19c16c799d150cc79cace3f8f894c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E2=80=9Cbhkumarn=E2=80=9D?= Bhuvanendra.KumarN@amd.com<mailto:Bhuvanendra.KumarN@amd.com>
Date: Thu, 2 Jun 2022 19:19:13 +0530
Subject: [PATCH] [PATCH 2/2] Binutils support for split-dwarf and dwarf-5.
This fix adds support for split-dwarf and dwarf5. There are 2 patches.
Basic sections dump like .debug_info.dwo, .debug_abbrev.dwo, .debug_str.dwo
etc are supported in the previous patch 1/2. location list and ranges list
sections dump with split-dwarf and dwarf5 are supported in this patch 2/2
and its continuation of patch 1/2.
.debug_loclists.dwo and .debug_rnglists.dwo section dumps are taken care in
this patch 2/2.
* dwarf.c(read_and_display_attr_value): Handle DW_FORM_loclistx
and DW_FORM_rnglistx for .dwo files.
(process_debug_info): Load .debug_loclists.dwo and
.debug_rnglists.dwo if exists.
(load_separate_debug_files): Load .debug_loclists and
.debug_rnglists if exists.
Include 2 entries in debug_displays table.
* dwarf.h (enum dwarf_section_display_enum): Include 2 entries.
---
binutils/dwarf.c | 39 +++++++++++++++++++++++++++++++++++++--
binutils/dwarf.h | 2 ++
2 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index e8f0ea4cf0c..7b4bb445da4 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -120,6 +120,7 @@ unsigned long dwarf_start_die;
int dwarf_check = 0;
static dwarf_vma str_offsets_base = 0;
#define DEBUG_STR_OFFSETS_HEADER_LEN 8
+#define DEBUG_LOC_RNGLISTS_SEC_HDR_LEN 12
/* Convenient constant, to avoid having to cast -1 to dwarf_vma when
testing whether e.g. a locview list is present. */
@@ -2792,7 +2793,34 @@ read_and_display_attr_value (unsigned long attribute,
offset = base + uvalue * pointer_size;
- if (do_wide)
+ const char *suffix = strrchr (section->name, '.');
+ bool dwo = suffix && strcmp (suffix, ".dwo") == 0;
+
+ if (form == DW_FORM_loclistx)
+ {
+ if (!dwo)
+ printf (_("%c(index: 0x%s): %s"), delimiter,
+ dwarf_vmatoa ("x", uvalue),
+ dwarf_vmatoa ("x", debug_info_p->loc_offsets [uvalue]));
+ else
+ printf (_("%c(index: 0x%s): %s"), delimiter,
+ dwarf_vmatoa ("x", uvalue),
+ dwarf_vmatoa ("x", fetch_indexed_value (uvalue, loclists_dwo)
+ + DEBUG_LOC_RNGLISTS_SEC_HDR_LEN));
+ }
+ else if (form == DW_FORM_rnglistx)
+ {
+ if (!dwo)
+ printf (_("%c(index: 0x%s): %s"), delimiter,
+ dwarf_vmatoa ("x", uvalue),
+ dwarf_vmatoa ("x", debug_info_p->range_lists [uvalue]));
+ else
+ printf (_("%c(index: 0x%s): %s"), delimiter,
+ dwarf_vmatoa ("x", uvalue),
+ dwarf_vmatoa ("x", fetch_indexed_value (uvalue, rnglists_dwo)
+ + DEBUG_LOC_RNGLISTS_SEC_HDR_LEN));
+ }
+ else if (do_wide)
/* We have already displayed the form name. */
printf (_("%c(index: 0x%s): %s"), delimiter,
dwarf_vmatoa ("x", uvalue),
@@ -3608,7 +3636,9 @@ process_debug_info (struct dwarf_section * section,
load_debug_section_with_follow (abbrev_sec, file);
load_debug_section_with_follow (loclists, file);
load_debug_section_with_follow (rnglists, file);
-
+ load_debug_section_with_follow (loclists_dwo, file);
+ load_debug_section_with_follow (rnglists_dwo, file);
+
if (debug_displays [abbrev_sec].section.start == NULL)
{
warn (_("Unable to locate %s section!\n"),
@@ -11896,6 +11926,9 @@ load_separate_debug_files (void * file, const char * filename)
&& load_debug_section (info, file))
{
load_debug_section (str_index, file);
+ load_debug_section (loclists, file);
+ load_debug_section (rnglists, file);
+
free_dwo_info ();
if (process_debug_info (& debug_displays[info].section, file, abbrev,
@@ -12265,10 +12298,12 @@ struct dwarf_section_display debug_displays[] =
{ { ".debug_line_str", ".zdebug_line_str", "", NO_ABBREVS }, display_debug_str, &do_debug_str, false },
{ { ".debug_loc", ".zdebug_loc", ".dwloc", NO_ABBREVS }, display_debug_loc, &do_debug_loc, true },
{ { ".debug_loclists", ".zdebug_loclists", "", NO_ABBREVS }, display_debug_loc, &do_debug_loc, true },
+ { { ".debug_loclists.dwo", ".zdebug_loclists.dwo", "", NO_ABBREVS }, display_debug_loc, &do_debug_loc, true },
{ { ".debug_pubtypes", ".zdebug_pubtypes", ".dwpbtyp", NO_ABBREVS }, display_debug_pubnames, &do_debug_pubtypes, false },
{ { ".debug_gnu_pubtypes", ".zdebug_gnu_pubtypes", "", NO_ABBREVS }, display_debug_gnu_pubnames, &do_debug_pubtypes, false },
{ { ".debug_ranges", ".zdebug_ranges", ".dwrnges", NO_ABBREVS }, display_debug_ranges, &do_debug_ranges, true },
{ { ".debug_rnglists", ".zdebug_rnglists", "", NO_ABBREVS }, display_debug_ranges, &do_debug_ranges, true },
+ { { ".debug_rnglists.dwo", ".zdebug_rnglists.dwo", "", NO_ABBREVS }, display_debug_ranges, &do_debug_ranges, true },
{ { ".debug_static_func", ".zdebug_static_func", "", NO_ABBREVS }, display_debug_not_supported, NULL, false },
{ { ".debug_static_vars", ".zdebug_static_vars", "", NO_ABBREVS }, display_debug_not_supported, NULL, false },
{ { ".debug_types", ".zdebug_types", "", ABBREV (abbrev) }, display_debug_types, &do_debug_info, true },
diff --git a/binutils/dwarf.h b/binutils/dwarf.h
index 040e674c6ce..86b635ef3c2 100644
--- a/binutils/dwarf.h
+++ b/binutils/dwarf.h
@@ -92,10 +92,12 @@ enum dwarf_section_display_enum
line_str,
loc,
loclists,
+ loclists_dwo,
pubtypes,
gnu_pubtypes,
ranges,
rnglists,
+ rnglists_dwo,
static_func,
static_vars,
types,
--
2.17.1
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