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author | Tom de Vries <tdevries@suse.de> | 2019-12-06 18:51:49 +0100 |
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committer | Tom de Vries <tdevries@suse.de> | 2019-12-06 18:51:49 +0100 |
commit | 93e55f0a031b0e677d22aaba00857de902ebe685 (patch) | |
tree | fca7f2c0c69822cf7a8007e2f1931a0be9fb1eb9 /gdb/psymtab.h | |
parent | e8dc9b5bfd234f61c6127d23cb80fbd4b0382115 (diff) | |
download | gdb-93e55f0a031b0e677d22aaba00857de902ebe685.zip gdb-93e55f0a031b0e677d22aaba00857de902ebe685.tar.gz gdb-93e55f0a031b0e677d22aaba00857de902ebe685.tar.bz2 |
[gdb/symtab] Prefer var def over decl
Consider the DWARF as generated by gcc with the tentative patch to fix gcc
PR91507 - "wrong debug for completed array with previous incomplete
declaration":
...
<1><f4>: Abbrev Number: 2 (DW_TAG_array_type)
<f5> DW_AT_type : <0xff>
<f9> DW_AT_sibling : <0xff>
<2><fd>: Abbrev Number: 3 (DW_TAG_subrange_type)
<2><fe>: Abbrev Number: 0
<1><ff>: Abbrev Number: 4 (DW_TAG_pointer_type)
<100> DW_AT_byte_size : 8
<101> DW_AT_type : <0x105>
<1><105>: Abbrev Number: 5 (DW_TAG_base_type)
<106> DW_AT_byte_size : 1
<107> DW_AT_encoding : 6 (signed char)
<108> DW_AT_name : (indirect string, offset: 0x19f): char
<1><10c>: Abbrev Number: 6 (DW_TAG_variable)
<10d> DW_AT_name : zzz
<111> DW_AT_decl_file : 1
<112> DW_AT_decl_line : 1
<113> DW_AT_decl_column : 14
<114> DW_AT_type : <0xf4>
<118> DW_AT_external : 1
<118> DW_AT_declaration : 1
<1><118>: Abbrev Number: 2 (DW_TAG_array_type)
<119> DW_AT_type : <0xff>
<11d> DW_AT_sibling : <0x128>
<1><12f>: Abbrev Number: 8 (DW_TAG_variable)
<130> DW_AT_specification: <0x10c>
<134> DW_AT_decl_line : 2
<135> DW_AT_decl_column : 7
<136> DW_AT_type : <0x118>
<13a> DW_AT_location : 9 byte block: 3 30 10 60 0 0 0 0 0 (DW_OP_addr: 601030)
...
The DWARF will result in two entries in the symbol table, a decl with type
char *[] and a def with type char*[2].
When trying to print the value of zzz:
...
$ gdb a.spec.out -batch -ex "p zzz"
...
the decl (rather than the def) will be found in the symbol table, which is
missing the location information, and consequently we get:
...
$1 = 0x601030 <zzz>
...
[ There is a fallback mechanism that finds the address of the variable in the
minimal symbol table, but that's not used here, because the type of the decl
does not specify a size. We could use the symbol size here to get the size
of the type, but that's currently not done: PR exp/24989. Still, fixing that
PR would not fix the generic case, where minimal symbol info is not
available. ]
Fix this by preferring defs over decls when searching in the symbol table.
Build and reg-tested on x86_64-linux.
gdb/ChangeLog:
2019-12-06 Tom de Vries <tdevries@suse.de>
PR symtab/24971
* block.c (best_symbol, better_symbol): New function.
(block_lookup_symbol_primary, block_lookup_symbol): Prefer def over
decl.
gdb/testsuite/ChangeLog:
2019-12-06 Tom de Vries <tdevries@suse.de>
* gdb.dwarf2/varval.exp: Add decl before def test.
Change-Id: Id92326cb8ef9903b121ef9e320658eb565d0f5a9
Diffstat (limited to 'gdb/psymtab.h')
0 files changed, 0 insertions, 0 deletions