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Re: [rfc] Set a breakpoint's type before adjusting its address
- From: Kevin Buettner <kevinb at redhat dot com>
- To: gdb-patches at sources dot redhat dot com
- Date: Wed, 2 May 2007 17:15:49 -0700
- Subject: Re: [rfc] Set a breakpoint's type before adjusting its address
- References: <email@example.com> <20070428214510.GA12239@caradoc.them.org>
On Sat, 28 Apr 2007 17:45:10 -0400
Daniel Jacobowitz <firstname.lastname@example.org> wrote:
> This happens because the breakpoint's location is already on the
> location chain, right?
> Alternatively, we could move that from the end
> of allocate_bp_location to the end of set_raw_breakpoint, and avoid
> the inconsistency.
If we can do it, I think it'd be nice to keep the code which allocates
the location together with the code which adds the newly allocated
location to the chain.
I agree that my earlier patch is not very nice in that
adjust_breakpoint_address() was being called with an only partially
initialized location on the location chain. That patch was a band-aid
in that it initialized those bits which a particular function
(read_memory_nobpt) cared about, but who knows what else might break
if some other function were called.
Appended below is a new patch which calls adjust_breakpoint_address()
prior to allocating the breakoint's location. What do you think of
* breakpoint.c (set_raw_breakpoint): Adjust breakpoint's address
prior to allocating its location.
RCS file: /cvs/src/src/gdb/breakpoint.c,v
retrieving revision 1.246
diff -u -p -r1.246 breakpoint.c
--- breakpoint.c 13 Apr 2007 13:50:32 -0000 1.246
+++ breakpoint.c 2 May 2007 23:57:06 -0000
@@ -4189,13 +4189,23 @@ struct breakpoint *
set_raw_breakpoint (struct symtab_and_line sal, enum bptype bptype)
struct breakpoint *b, *b1;
+ CORE_ADDR adjusted_address;
b = (struct breakpoint *) xmalloc (sizeof (struct breakpoint));
memset (b, 0, sizeof (*b));
+ /* Adjust the breakpoint's address prior to allocating a location.
+ Once we call allocate_bp_location(), that mostly uninitialized
+ location will be placed on the location chain. Adjustment of the
+ breakpoint may cause read_memory_nobpt() to be called and we do
+ not want its scan of the location chain to find a breakpoint and
+ location that's only been partially initialized. */
+ adjusted_address = adjust_breakpoint_address (sal.pc, bptype);
b->loc = allocate_bp_location (b, bptype);
b->loc->requested_address = sal.pc;
- b->loc->address = adjust_breakpoint_address (b->loc->requested_address,
+ b->loc->address = adjusted_address;
if (sal.symtab == NULL)
b->source_file = NULL;