[PATCH v2 1/2] DWARFv5: Handle DW_MACRO_define_strx and DW_MACRO_undef_strx macro entries.
nitachra
Nitika.Achra@amd.com
Thu Sep 24 13:31:47 GMT 2020
>> gdb/ChangeLog:
>> * dwarf2/macro.c (dwarf_decode_macro_bytes): Handle DW_MACRO_define_strx
>> and DW_MACRO_undef_strx.
>> (dwarf_decode_macros): Likewise
>> * dwarf2/read.c (dwarf_decode_macros): Pass str_offsets_base in the parameters
>> which is the value of DW_AT_str_offsets_base.
>> * dwarf2/macro.h (dwarf_decode_macros): Modify the definition to include
>> str_offsets_base.
>Thank you. This is ok.
>Tom
Hi Tom,
Thanks for the review. Could you please push this patch for me? All the
Changelogs are in place. Or can you tell me the procedure to add myself in
the list of contributors so that I can push it myself?
Regards,
Nitika
---
GDB complaints "During symbol reading: unrecognized DW_MACFINO
opcode 0xb" with the testcase given below. Clang is emitting
DW_MACRO_define_strx and DW_MACRO_undef_strx entries in .debug_macro
section which are not supported in GDB. This patch handles them.
DW_MACRO_define_strx and DW_MACRO_undef_strx are added in DWARFv5.
They have two operands. The first operand encodes the line number of
the #define or #undef macro directive. The second operand identifies
a string; it is represented using an unsigned LEB128 encoded value,
which is interpreted as a zero-based index into an array of offsets
in the .debug_str_offsets section. This is as per the section 6.3.2.1
of Dwarf Debugging Information Format Version 5.
Test case used:
#define MAX_SIZE 10
int main(void)
{
int size = 0;
size = size + MAX_SIZE;
printf("\n The value of size is [%d]\n",size);
return 0;
}
clang -gdwarf-5 -fdebug-macro macro.c -o macro.out
Before the patch:
gdb/new_gdb/binutils-gdb/build/bin/gdb -q macro.out -ex "set complaints 1" -ex "start"
Reading symbols from macro.out...
During symbol reading: unrecognized DW_MACFINO opcode 0xb
Temporary breakpoint 1 at 0x4004df: file macro.c, line 7.
Starting program: /home/nitika/workspace/macro.out
Temporary breakpoint 1, main () at macro.c:7
7 int size = 0;
(gdb)
Tested by running the testsuite before and after the patch with
-gdwarf-5 and there is no increase in the number of test cases
that fails. Used clang 11.0.0.
gdb/ChangeLog:
* dwarf2/macro.c (dwarf_decode_macro_bytes): Handle DW_MACRO_define_strx
and DW_MACRO_undef_strx.
(dwarf_decode_macros): Likewise
* dwarf2/read.c (dwarf_decode_macros): Pass str_offsets_base in the parameters
which is the value of DW_AT_str_offsets_base.
* dwarf2/macro.h (dwarf_decode_macros): Modify the definition to include
str_offsets_base.
---
gdb/ChangeLog | 10 +++++++
gdb/dwarf2/macro.c | 71 ++++++++++++++++++++++++++++++++++++++++++++--
gdb/dwarf2/macro.h | 3 ++
gdb/dwarf2/read.c | 21 +++++++++++++-
4 files changed, 101 insertions(+), 4 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ce9cef5f51..7b431d275e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2020-09-24 Nitika Achra <Nitika.Achra@amd.com>
+
+ * dwarf2/macro.c (dwarf_decode_macro_bytes): Handle DW_MACRO_define_strx
+ and DW_MACRO_undef_strx.
+ (dwarf_decode_macros): Likewise
+ * dwarf2/read.c (dwarf_decode_macros): Pass str_offsets_base in the parameters
+ which is the value of DW_AT_str_offsets_base.
+ * dwarf2/macro.h (dwarf_decode_macros): Modify the definition to include
+ str_offsets_base.
+
2020-09-21 Tom Tromey <tromey@adacore.com>
* sparc-tdep.c (sparc32_skip_prologue): Use
diff --git a/gdb/dwarf2/macro.c b/gdb/dwarf2/macro.c
index d047d806f8..9208614564 100644
--- a/gdb/dwarf2/macro.c
+++ b/gdb/dwarf2/macro.c
@@ -427,6 +427,9 @@ dwarf_decode_macro_bytes (dwarf2_per_objfile *per_objfile,
const struct dwarf2_section_info *section,
int section_is_gnu, int section_is_dwz,
unsigned int offset_size,
+ struct dwarf2_section_info *str_section,
+ struct dwarf2_section_info *str_offsets_section,
+ ULONGEST str_offsets_base,
htab_t include_hash)
{
struct objfile *objfile = per_objfile->objfile;
@@ -561,6 +564,53 @@ dwarf_decode_macro_bytes (dwarf2_per_objfile *per_objfile,
}
break;
+ case DW_MACRO_define_strx:
+ case DW_MACRO_undef_strx:
+ {
+ unsigned int bytes_read;
+
+ int line = read_unsigned_leb128 (abfd, mac_ptr, &bytes_read);
+ mac_ptr += bytes_read;
+ int offset_index = read_unsigned_leb128 (abfd, mac_ptr, &bytes_read);
+ mac_ptr += bytes_read;
+
+ str_offsets_section->read (objfile);
+ const gdb_byte *info_ptr = (str_offsets_section->buffer
+ + str_offsets_base
+ + offset_index * offset_size);
+
+ const char *macinfo_str = (macinfo_type == DW_MACRO_define_strx ?
+ "DW_MACRO_define_strx" : "DW_MACRO_undef_strx");
+
+ if (str_offsets_base + offset_index * offset_size
+ >= str_offsets_section->size)
+ {
+ complaint (_("%s pointing outside of .debug_str_offsets section "
+ "[in module %s]"), macinfo_str, objfile_name (objfile));
+ break;
+ }
+
+ ULONGEST str_offset = read_offset (abfd, info_ptr, offset_size);
+
+ const char *body = str_section->read_string (objfile, str_offset,
+ macinfo_str);
+ if (current_file == nullptr)
+ {
+ /* DWARF violation as no main source is present. */
+ complaint (_("debug info with no main source gives macro %s "
+ "on line %d: %s"),
+ macinfo_type == DW_MACRO_define_strx ? _("definition")
+ : _("undefinition"), line, body);
+ break;
+ }
+
+ if (macinfo_type == DW_MACRO_define_strx)
+ parse_macro_definition (current_file, line, body);
+ else
+ macro_undef (current_file, line, body);
+ }
+ break;
+
case DW_MACRO_start_file:
{
unsigned int bytes_read;
@@ -671,7 +721,8 @@ dwarf_decode_macro_bytes (dwarf2_per_objfile *per_objfile,
new_mac_ptr, include_mac_end,
current_file, lh, section,
section_is_gnu, is_dwz, offset_size,
- include_hash);
+ str_section, str_offsets_section,
+ str_offsets_base, include_hash);
htab_remove_elt (include_hash, (void *) new_mac_ptr);
}
@@ -712,7 +763,9 @@ dwarf_decode_macros (dwarf2_per_objfile *per_objfile,
buildsym_compunit *builder,
const dwarf2_section_info *section,
const struct line_header *lh, unsigned int offset_size,
- unsigned int offset, int section_is_gnu)
+ unsigned int offset, struct dwarf2_section_info *str_section,
+ struct dwarf2_section_info *str_offsets_section,
+ ULONGEST str_offsets_base, int section_is_gnu)
{
bfd *abfd;
const gdb_byte *mac_ptr, *mac_end;
@@ -814,6 +867,17 @@ dwarf_decode_macros (dwarf2_per_objfile *per_objfile,
mac_ptr += offset_size;
}
break;
+ case DW_MACRO_define_strx:
+ case DW_MACRO_undef_strx:
+ {
+ unsigned int bytes_read;
+
+ read_unsigned_leb128 (abfd, mac_ptr, &bytes_read);
+ mac_ptr += bytes_read;
+ read_unsigned_leb128 (abfd, mac_ptr, &bytes_read);
+ mac_ptr += bytes_read;
+ }
+ break;
case DW_MACRO_import:
case DW_MACRO_import_sup:
@@ -861,5 +925,6 @@ dwarf_decode_macros (dwarf2_per_objfile *per_objfile,
*slot = (void *) mac_ptr;
dwarf_decode_macro_bytes (per_objfile, builder, abfd, mac_ptr, mac_end,
current_file, lh, section, section_is_gnu, 0,
- offset_size, include_hash.get ());
+ offset_size, str_section, str_offsets_section,
+ str_offsets_base, include_hash.get ());
}
diff --git a/gdb/dwarf2/macro.h b/gdb/dwarf2/macro.h
index d874068947..0a7ac55fc0 100644
--- a/gdb/dwarf2/macro.h
+++ b/gdb/dwarf2/macro.h
@@ -28,6 +28,9 @@ extern void dwarf_decode_macros (dwarf2_per_objfile *per_objfile,
const struct line_header *lh,
unsigned int offset_size,
unsigned int offset,
+ dwarf2_section_info *str_section,
+ dwarf2_section_info *str_offsets_section,
+ ULONGEST str_offsets_base,
int section_is_gnu);
#endif /* GDB_DWARF2_MACRO_H */
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index a339141ce0..0729b6a413 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -23878,8 +23878,27 @@ dwarf_decode_macros (struct dwarf2_cu *cu, unsigned int offset,
buildsym_compunit *builder = cu->get_builder ();
+ struct dwarf2_section_info *str_offsets_section;
+ struct dwarf2_section_info *str_section;
+ ULONGEST str_offsets_base;
+
+ if (cu->dwo_unit != nullptr)
+ {
+ str_offsets_section = &cu->dwo_unit->dwo_file
+ ->sections.str_offsets;
+ str_section = &cu->dwo_unit->dwo_file->sections.str;
+ str_offsets_base = cu->header.addr_size;
+ }
+ else
+ {
+ str_offsets_section = &per_objfile->per_bfd->str_offsets;
+ str_section = &per_objfile->per_bfd->str;
+ str_offsets_base = *cu->str_offsets_base;
+ }
+
dwarf_decode_macros (per_objfile, builder, section, lh,
- offset_size, offset, section_is_gnu);
+ offset_size, offset, str_section, str_offsets_section,
+ str_offsets_base, section_is_gnu);
}
/* Return the .debug_loc section to use for CU.
--
2.17.1
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