[3/4] Allow display of negative offsets in print_address_symbolic()
Commit Message
When examining addresses associated with blocks with non-contiguous
address ranges, it's not uncommon to see large positive offsets which,
for some address width, actually represent a smaller negative offset.
Here's an example taken from the test case:
(gdb) x/i foo_cold
0x40110d <foo+4294967277>: push %rbp
This commit causes cases like the above to be displayed like this (below)
instead:
(gdb) x/i foo_cold
0x40110d <foo-19>: push %rbp
gdb/ChangeLog:
* printcmd.c (print_address_symbolic): Print negative offsets.
(build_address_symbolic): Force signed arithmetic when computing
offset.
---
gdb/printcmd.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Comments
On 6/8/19 8:54 PM, Kevin Buettner wrote:
> When examining addresses associated with blocks with non-contiguous
> address ranges, it's not uncommon to see large positive offsets which,
> for some address width, actually represent a smaller negative offset.
> Here's an example taken from the test case:
>
> (gdb) x/i foo_cold
> 0x40110d <foo+4294967277>: push %rbp
>
> This commit causes cases like the above to be displayed like this (below)
> instead:
>
> (gdb) x/i foo_cold
> 0x40110d <foo-19>: push %rbp
>
> gdb/ChangeLog:
>
> * printcmd.c (print_address_symbolic): Print negative offsets.
> (build_address_symbolic): Force signed arithmetic when computing
> offset.
Seems reasonable to me, if we assume that the symbol name to put
within <> is "foo".
This change makes makes me doubt that, though. We're looking at
the lower level, disassembly code. I think I'd want to see
0x40110d <foo_cold+0>:
there?
E.g., I might want to follow up with
disassemble foo_cold.
But the present state of things, I wouldn't be able to see the
foo_cold symbol, where it starts?
Maybe a larger disassemble output including several cold sections
in view would help determine the best output.
Thanks,
Pedro Alves
@@ -537,7 +537,7 @@ print_address_symbolic (struct gdbarch *gdbarch, CORE_ADDR addr,
fputs_filtered ("<", stream);
fputs_styled (name.c_str (), function_name_style.style (), stream);
if (offset != 0)
- fprintf_filtered (stream, "+%u", (unsigned int) offset);
+ fprintf_filtered (stream, "%+d", offset);
/* Append source filename and line number if desired. Give specific
line # of this addr, if we have it; else line # of the nearest symbol. */
@@ -666,7 +666,7 @@ build_address_symbolic (struct gdbarch *gdbarch,
&& name_location + max_symbolic_offset > name_location)
return 1;
- *offset = addr - name_location;
+ *offset = (LONGEST) addr - name_location;
*name = name_temp;