The "list" command allows specifying the name of variables as
argument, not just functions, so that users can type "list
a_global_variable".
That support is a broken when it comes to ambiguous locations though.
If there's more than one such global variable in the program, e.g.,
static globals in different compilation units, GDB ends up listing the
source of the first variable it finds, only.
linespec.c does find both symbol and minsym locations for all the
globals. The problem is that it ends up merging all the resulting
sals into one, because they all have address, zero. I.e., all sals
end up with sal.pc == 0, so maybe_add_address returns false for all
but the first.
The zero addresses appear because:
- in the minsyms case, linespec.c:minsym_found incorrectly treats all
minsyms as if they were function/text symbols. In list mode we can
end up with data symbols there, and we shouldn't be using
find_pc_sect_line on data symbols.
- in the debug symbols case, symbol_to_sal misses recording an address
(sal.pc) for non-block, non-label symbols.
gdb/ChangeLog:
2017-09-20 Pedro Alves <palves@redhat.com>
* linespec.c (minsym_found): Handle non-text minsyms.
(symbol_to_sal): Record a sal.pc for non-block, non-label symbols.
gdb/testsuite/ChangeLog:
2017-09-20 Pedro Alves <palves@redhat.com>
* gdb.base/list-ambiguous.exp (test_list_ambiguous_function):
Rename to ...
(test_list_ambiguous_symbol): ... this and add a symbol name
parameter. Adjust.
(test_list_ambiguous_function): Reimplement on top of
test_list_ambiguous_symbol and also test listing ambiguous
variables.
* gdb.base/list-ambiguous0.c (ambiguous): Rename to ...
(ambiguous_fun): ... this.
(ambiguous_var): New.
* gdb.base/list-ambiguous1.c (ambiguous): Rename to ...
(ambiguous_fun): ... this.
(ambiguous_var): New.
Currently, with "list LINESPEC1,LINESPEC2", if one of the linespecs is
ambiguous, i.e., if it expands to multiple locations, you get this
seemingly odd output:
(gdb) list foo,bar
file: "file0.c", line number: 26
file: "file1.c", line number: 29
Since "foo" above expands to multiple locations, the specified range
is indeterminate, and GDB is trying to be helpful by showing you what
was ambiguous. It looks confusing to me, though. I think it'd be
much more user friendly if GDB actually told you that, like this:
(gdb) list foo,bar
Specified first line 'foo' is ambiguous:
file: "file0.c", line number: 26
file: "file1.c", line number: 29
(gdb) list bar,foo
Specified last line 'foo' is ambiguous:
file: "file0.c", line number: 26
file: "file1.c", line number: 29
Note, I'm using "first" and "last" in the output because that's what
the manual uses:
~~~
list first,last
Print lines from first to last. [...]
~~~
Tested on x86-64 GNU/Linux.
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* cli/cli-cmds.c (edit_command): Pass message to
ambiguous_line_spec.
(list_command): Pass message to ambiguous_line_spec. Say
"first"/"last" instead of "start" and "end" to be consistent with
the manual.
(ambiguous_line_spec): Add 'format' and vararg parameters. Use
them to print formatted message.
gdb/testsuite/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* gdb.base/list-ambiguous.exp: New file.
* gdb.base/list-ambiguous0.c: New file.
* gdb.base/list-ambiguous1.c: New file.
* gdb.base/list.exp (test_list_range): Adjust expected output.
Pedro Alves