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DWARFv5: Handle DW_MACRO_define_strx and DW_MACRO_undef_strx macro entries.

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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.
This commit is contained in:
nitachra
2020-09-20 23:22:59 +05:30
committed by Alok Kumar Sharma
parent 71a74ee72d
commit 048fde1ef4
4 changed files with 101 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
gdb/ChangeLog
View File

@@ -1,3 +1,13 @@
2020-10-02 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.
2020-10-01 Kamil Rytarowski <n54@gmx.com>
* i386-tdep.h (i386nbsd_sc_reg_offset): Remove.

71
gdb/dwarf2/macro.c
View File

@@ -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 ());
}

3
gdb/dwarf2/macro.h
View File

@@ -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 */

21
gdb/dwarf2/read.c
View File

@@ -23900,8 +23900,27 @@ 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.