Re: [PATCH] Fix for incorect breakpoint set in case of clang compiled binary

H.J. Lu
2012-11-19T14:43:15Z

On Mon, Nov 19, 2012 at 12:06 AM, KARTHIKVENKATESH BHAT
<kv.bhat@samsung.com> wrote:
> Dear All,
> I wanted to add a patch in i386-tdep.c . Similar to what is done in other architectures such as ARM,
> instead of actually going through the complete prologue if we can use the symbol table information to resolve prologue end.
>
>
> Index: gdb/i386-tdep.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/i386-tdep.c,v
> retrieving revision 1.362
> diff -u -p -r1.362 i386-tdep.c
> --- gdb/i386-tdep.c 12 Nov 2012 21:59:06 -0000 1.362
> +++ gdb/i386-tdep.c 19 Nov 2012 07:56:45 -0000
> @@ -1582,8 +1582,30 @@ i386_skip_prologue (struct gdbarch *gdba
> CORE_ADDR pc;
> gdb_byte op;
> int i;
> + cache.locals = -1;
> + CORE_ADDR func_addr;
> + struct symtab *s = find_pc_symtab (func_addr);
> +
> + if (find_pc_partial_function (start_pc, NULL, &func_addr, NULL))
> + {
> + CORE_ADDR post_prologue_pc
> + = skip_prologue_using_sal (gdbarch, func_addr);
> +
> + /* GCC always emits a line note before the prologue and another
> + one after, even if the two are at the same address or on the
> + same line. Take advantage of this so that we do not need to
> + know every instruction that might appear in the prologue. We
> + will have producer information for most binaries; if it is
> + missing (e.g. for -gstabs), assuming the GNU tools. */
> + if (post_prologue_pc
> + && (s == NULL
> + || s->producer == NULL
> + || strncmp (s->producer, "GNU ", sizeof ("GNU ") - 1) == 0
> + || strncmp (s->producer, "clang ", sizeof ("clang ") - 1) == 0))
> + return max (start_pc, post_prologue_pc);
> + }
> +
>
>

It doesn't look like target-dependent. If we do this, why not
make it a target-independent function make all targets call it?

--
H.J.