Since 4d7188abfdf2 ("gdbsupport: add debug assertions in
gdb::optional::get"), some macro-related tests fail on Ubuntu 20.04 with
the system gcc 9.3.0 compiler when building with _GLIBCXX_DEBUG. For
example, gdb.base/info-macros.exp results in:
(gdb) break -qualified main
/home/smarchi/src/binutils-gdb/gdb/../gdbsupport/gdb_optional.h:206: internal-error: T& gdb::optional<T>::get() [with T = long unsigned int]: Assertion `this->has_value ()' failed.
The binary contains DWARF 4 debug info and includes a pre-standard
(pre-DWARF 5) .debug_macro section. The CU doesn't have a
DW_AT_str_offsets_base attribute (which doesn't exist in DWARF 4). The
field dwarf2_cu::str_offsets_base is therefore empty. At
dwarf2/read.c:24138, we unconditionally read the value in the optional,
which triggers the assertion shown above.
The same thing happens when building the test program with DWARF 5 with
the same gcc compiler, as that version of gcc doesn't use indirect
string forms, even with DWARF 5. So it still doesn't add a
DW_AT_str_offsets_base attribute on the CU.
Fix that by propagating down a gdb::optional<ULONGEST> for the str
offsets base instead of ULONGEST. That value is only used in
dwarf_decode_macro_bytes, when encountering an "strx" macro operation
(DW_MACRO_define_strx or DW_MACRO_undef_strx). Add a check there that
we indeed have a value in the optional before reading it. This is
unlikely to happen, but could happen in theory with an erroneous file
that uses DW_MACRO_define_strx but does not provide a
DW_AT_str_offsets_base (in practice, some things would probably have
failed before and stopped processing of debug info). I tested the
complaint by inverting the condition and using a clang-compiled binary,
which uses the strx operators. This is the result:
During symbol reading: use of DW_MACRO_define_strx with unknown string offsets base [in module /home/simark/build/binutils-gdb/gdb/testsuite/outputs/gdb.base/info-macros/info-macros]
The test now passes cleanly with the setup mentioned above, and the
testsuite looks on par with how it was before 4d7188abfdf2.
Change-Id: I7ebd2724beb7b9b4178872374c2a177aea696e77
This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
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.
While doing the psymtab-sharing patchset, I avoided renaming variables
unnecessarily to avoid adding noise to patches, but I'd like to do it
now. Basically, we have these dwarf2 per-something structures:
- dwarf2_per_objfile
- dwarf2_per_bfd
- dwarf2_per_cu_data
I named the instances of dwarf2_per_bfd `per_bfd` and most of instances
of dwarf2_per_cu_data are called `per_cu`. Most pre-existing instances
of dwarf2_per_objfile are named `dwarf2_per_objfile`. For consistency
with the other type, I'd like to rename them to just `per_objfile`. The
`dwarf2_` prefix is superfluous, since it's already clear we are in
dwarf2 code. It also helps reducing the line wrapping by saving 7
precious columns.
gdb/ChangeLog:
* dwarf2/comp-unit.c, dwarf2/comp-unit.h, dwarf2/index-cache.c,
dwarf2/index-cache.h, dwarf2/index-write.c,
dwarf2/index-write.h, dwarf2/line-header.c,
dwarf2/line-header.h, dwarf2/macro.c, dwarf2/macro.h,
dwarf2/read.c, dwarf2/read.h: Rename struct dwarf2_per_objfile
variables and fields from `dwarf2_per_objfile` to just
`per_objfile` throughout.
Change-Id: I3c45cdcc561265e90df82cbd36b4b4ef2fa73aef
This changes the DWARF macro reader to use a const dwarf2_section_info.
gdb/ChangeLog
2020-03-26 Tom Tromey <tom@tromey.com>
* dwarf2/macro.h (dwarf_decode_macros): Make section parameter
const.
* dwarf2/macro.c (skip_form_bytes, skip_unknown_opcode)
(dwarf_decode_macro_bytes, dwarf_decode_macros): Make section
parameter const.
This moves some more code out of dwarf2/read.c, introducing new files
dwarf2/macro.c and dwarf2/macro.h.
gdb/ChangeLog
2020-03-26 Tom Tromey <tom@tromey.com>
* dwarf2/read.c (dwarf2_macro_malformed_definition_complaint)
(macro_start_file, consume_improper_spaces)
(parse_macro_definition, skip_form_bytes, skip_unknown_opcode)
(dwarf_parse_macro_header, dwarf_decode_macro_bytes)
(dwarf_decode_macros): Move to macro.c.
* dwarf2/macro.c: New file.
* dwarf2/macro.h: New file.
* Makefile.in (COMMON_SFILES): Add dwarf2/macro.c.
