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ff8cba872e
This is about supporting an Ada-induced DWARF construct related to
ranged types.
To reproduce the issue this patch originated from, you can type:
$ fedabipkgdiff --self-compare -a --from fc37 gprbuild
From that gprbuild package from fc37, consider this subrange_type DIE
coming from the debuginfo file prtests/gprbuild-2020-11.fc37.aarch64:
1 [ 3c10d] subrange_type abbrev: 34
2 type (ref_addr) [ 6191e]
3 lower_bound (sdata) 2
4 upper_bound (ref_udata) [ 3c0eb]
At line 4, look at how the DW_AT_upper_bound attribute is a reference
to another DIE, instead of being a (signed) constant value, like the
DW_AT_lower_bound attribute at line 3. The referenced DIE is at
offset 0x3c0eb.
How do we get the actual value of the upper_bound of that subrange
type?
To answer that question, let's look at the DIE, at offset 0x3c0eb that
is referenced by the DW_AT_upper_bound attribute at line 4:
1 [ 3c0eb] member abbrev: 87
2 name (strp) "last"
3 decl_file (data1) a-coinve.ads (35)
4 decl_line (data2) 415
5 decl_column (data1) 24
6 type (ref_udata) [ 3c0f7]
It's a data member which type is referenced at line 6. Let's look at
that type, which offset is 0x3c0f7:
1 [ 3c0f7] subrange_type abbrev: 122
2 upper_bound (sdata) 99999999
3 name (strp) "gpr__names__name_vectors__T449bXn"
4 type (ref_addr) [ 6191e]
5 artificial (flag_present) yes
That type is a DW_TAG_subrange_type and its DW_AT_upper_bound value is
a constant. Finally.
Actually, the value of DW_AT_upper_bound of this DIE at offset 0x3c0f7
is the value of the DW_AT_upper_bound of the subrange_type DIE at
offset 0x3c10d that we were initially looking for.
The DIE at 0x3c0f7 is said to be indirectly referenced by the DIE at
0x3c10d, through its DW_AT_upper_bound attribute.
This patch supports retrieving the value of the DW_AT_upper_bound of
0x3c10d through the 0x3c0f7 DIE that it indirectly references.
The package gprbuild from fc37 now passes self comparison with this patch.
* src/abg-dwarf-reader.cc (subrange_die_indirect_bound_value)
(subrange_die_indirectly_references_subrange_die): Define new
static function.
(build_subrange_type): If the value of DW_AT_upper_bound is not a
constant, try to consider it as an indirect reference to a
DW_TAG_subrange_type DIE, whose DW_AT_upper_bound might carry the
constant value that we are looking for.
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
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|---|---|---|
| .. | ||
| abg-btf-reader.cc | ||
| abg-comp-filter.cc | ||
| abg-comparison-priv.h | ||
| abg-comparison.cc | ||
| abg-config.cc | ||
| abg-corpus-priv.h | ||
| abg-corpus.cc | ||
| abg-ctf-reader.cc | ||
| abg-default-reporter.cc | ||
| abg-diff-utils.cc | ||
| abg-dwarf-reader.cc | ||
| abg-elf-based-reader.cc | ||
| abg-elf-helpers.cc | ||
| abg-elf-helpers.h | ||
| abg-elf-reader.cc | ||
| abg-fe-iface.cc | ||
| abg-hash.cc | ||
| abg-ini.cc | ||
| abg-internal.h | ||
| abg-ir-priv.h | ||
| abg-ir.cc | ||
| abg-leaf-reporter.cc | ||
| abg-libxml-utils.cc | ||
| abg-reader.cc | ||
| abg-regex.cc | ||
| abg-reporter-priv.cc | ||
| abg-reporter-priv.h | ||
| abg-suppression-priv.h | ||
| abg-suppression.cc | ||
| abg-symtab-reader.cc | ||
| abg-symtab-reader.h | ||
| abg-tools-utils.cc | ||
| abg-traverse.cc | ||
| abg-viz-common.cc | ||
| abg-viz-dot.cc | ||
| abg-viz-svg.cc | ||
| abg-workers.cc | ||
| abg-writer.cc | ||
| Makefile.am | ||