* breakpoint.c: Add comments regarding within_scope future direction.
This commit is contained in:
Jim Kingdon
parent
ee7e82fedb
commit
fa99ebe19f
|
|
@ -1,5 +1,7 @@
|
|||
Wed Apr 14 17:12:51 1993 Jim Kingdon (kingdon@cygnus.com)
|
||||
|
||||
* breakpoint.c: Add comments regarding within_scope future direction.
|
||||
|
||||
* Version 4.8.3.
|
||||
|
||||
* xcoffread.c (record_include_{begin,end}): Change fatal to complain.
|
||||
|
|
|
|||
155
gdb/breakpoint.c
155
gdb/breakpoint.c
|
|
@ -790,6 +790,121 @@ bpstat_alloc (b, cbs)
|
|||
bs->print_it = print_it_normal;
|
||||
return bs;
|
||||
}
|
||||
|
||||
/* Return the frame which we can use to evaluate the expression
|
||||
whose valid block is valid_block, or NULL if not in scope.
|
||||
|
||||
This whole concept is probably not the way to do things (it is incredibly
|
||||
slow being the main reason, not to mention fragile (e.g. the sparc
|
||||
frame pointer being fetched as 0 bug causes it to stop)). Instead,
|
||||
introduce a version of "struct frame" which survives over calls to the
|
||||
inferior, but which is better than FRAME_ADDR in the sense that it lets
|
||||
us evaluate expressions relative to that frame (on some machines, it
|
||||
can just be a FRAME_ADDR). Save one of those instead of (or in addition
|
||||
to) the exp_valid_block, and then use it to evaluate the watchpoint
|
||||
expression, with no need to do all this backtracing every time.
|
||||
|
||||
Or better yet, what if it just copied the struct frame and its next
|
||||
frame? Off the top of my head, I would think that would work
|
||||
because things like (a29k) rsize and msize, or (sparc) bottom just
|
||||
depend on the frame, and aren't going to be different just because
|
||||
the inferior has done something. Trying to recalculate them
|
||||
strikes me as a lot of work, possibly even impossible. Saving the
|
||||
next frame is needed at least on a29k, where get_saved_register
|
||||
uses fi->next->saved_msp. For figuring out whether that frame is
|
||||
still on the stack, I guess this needs to be machine-specific (e.g.
|
||||
a29k) but I think
|
||||
|
||||
read_register (FP_REGNUM) INNER_THAN watchpoint_frame->frame
|
||||
|
||||
would generally work.
|
||||
|
||||
Of course the scope of the expression could be less than a whole
|
||||
function; perhaps if the innermost frame is the one which the
|
||||
watchpoint is relative to (another machine-specific thing, usually
|
||||
|
||||
FRAMELESS_FUNCTION_INVOCATION (get_current_frame(), fromleaf)
|
||||
read_register (FP_REGNUM) == wp_frame->frame
|
||||
&& !fromleaf
|
||||
|
||||
), *then* it could do a
|
||||
|
||||
contained_in (get_current_block (), wp->exp_valid_block).
|
||||
|
||||
*/
|
||||
|
||||
FRAME
|
||||
within_scope (valid_block)
|
||||
struct block *valid_block;
|
||||
{
|
||||
FRAME fr = get_current_frame ();
|
||||
struct frame_info *fi = get_frame_info (fr);
|
||||
CORE_ADDR func_start;
|
||||
|
||||
/* If caller_pc_valid is true, we are stepping through
|
||||
a function prologue, which is bounded by callee_func_start
|
||||
(inclusive) and callee_prologue_end (exclusive).
|
||||
caller_pc is the pc of the caller.
|
||||
|
||||
Yes, this is hairy. */
|
||||
static int caller_pc_valid = 0;
|
||||
static CORE_ADDR caller_pc;
|
||||
static CORE_ADDR callee_func_start;
|
||||
static CORE_ADDR callee_prologue_end;
|
||||
|
||||
find_pc_partial_function (fi->pc, (PTR)NULL, &func_start);
|
||||
func_start += FUNCTION_START_OFFSET;
|
||||
if (fi->pc == func_start)
|
||||
{
|
||||
/* We just called a function. The only other case I
|
||||
can think of where the pc would equal the pc of the
|
||||
start of a function is a frameless function (i.e.
|
||||
no prologue) where we branch back to the start
|
||||
of the function. In that case, SKIP_PROLOGUE won't
|
||||
find one, and we'll clear caller_pc_valid a few lines
|
||||
down. */
|
||||
caller_pc_valid = 1;
|
||||
caller_pc = SAVED_PC_AFTER_CALL (fr);
|
||||
callee_func_start = func_start;
|
||||
SKIP_PROLOGUE (func_start);
|
||||
callee_prologue_end = func_start;
|
||||
}
|
||||
if (caller_pc_valid)
|
||||
{
|
||||
if (fi->pc < callee_func_start
|
||||
|| fi->pc >= callee_prologue_end)
|
||||
caller_pc_valid = 0;
|
||||
}
|
||||
|
||||
if (contained_in (block_for_pc (caller_pc_valid
|
||||
? caller_pc
|
||||
: fi->pc),
|
||||
valid_block))
|
||||
{
|
||||
return fr;
|
||||
}
|
||||
fr = get_prev_frame (fr);
|
||||
|
||||
/* If any active frame is in the exp_valid_block, then it's
|
||||
OK. Note that this might not be the same invocation of
|
||||
the exp_valid_block that we were watching a little while
|
||||
ago, or the same one as when the watchpoint was set (e.g.
|
||||
we are watching a local variable in a recursive function.
|
||||
When we return from a recursive invocation, then we are
|
||||
suddenly watching a different instance of the variable).
|
||||
|
||||
At least for now I am going to consider this a feature. */
|
||||
for (; fr != NULL; fr = get_prev_frame (fr))
|
||||
{
|
||||
fi = get_frame_info (fr);
|
||||
if (contained_in (block_for_pc (fi->pc),
|
||||
valid_block))
|
||||
{
|
||||
return fr;
|
||||
}
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/* Possible return values for watchpoint_check (this can't be an enum
|
||||
because of check_errors). */
|
||||
|
|
@ -806,14 +921,22 @@ watchpoint_check (p)
|
|||
PTR p;
|
||||
{
|
||||
bpstat bs = (bpstat) p;
|
||||
FRAME fr;
|
||||
|
||||
int within_current_scope;
|
||||
if (bs->breakpoint_at->exp_valid_block != NULL)
|
||||
within_current_scope =
|
||||
contained_in (get_selected_block (), bs->breakpoint_at->exp_valid_block);
|
||||
else
|
||||
if (bs->breakpoint_at->exp_valid_block == NULL)
|
||||
within_current_scope = 1;
|
||||
|
||||
else
|
||||
{
|
||||
fr = within_scope (bs->breakpoint_at->exp_valid_block);
|
||||
within_current_scope = fr != NULL;
|
||||
if (within_current_scope)
|
||||
/* If we end up stopping, the current frame will get selected
|
||||
in normal_stop. So this call to select_frame won't affect
|
||||
the user. */
|
||||
select_frame (fr, -1);
|
||||
}
|
||||
|
||||
if (within_current_scope)
|
||||
{
|
||||
/* We use value_{,free_to_}mark because it could be a
|
||||
|
|
@ -2615,6 +2738,9 @@ static void
|
|||
enable_breakpoint (bpt)
|
||||
struct breakpoint *bpt;
|
||||
{
|
||||
FRAME save_selected_frame;
|
||||
int save_selected_frame_level = -1;
|
||||
|
||||
bpt->enable = enabled;
|
||||
|
||||
if (xgdb_verbose && bpt->type == bp_breakpoint)
|
||||
|
|
@ -2623,14 +2749,20 @@ enable_breakpoint (bpt)
|
|||
check_duplicates (bpt->address);
|
||||
if (bpt->type == bp_watchpoint)
|
||||
{
|
||||
if (bpt->exp_valid_block != NULL
|
||||
&& !contained_in (get_selected_block (), bpt->exp_valid_block))
|
||||
if (bpt->exp_valid_block != NULL)
|
||||
{
|
||||
printf_filtered ("\
|
||||
FRAME fr = within_scope (bpt->exp_valid_block);
|
||||
if (fr == NULL)
|
||||
{
|
||||
printf_filtered ("\
|
||||
Cannot enable watchpoint %d because the block in which its expression\n\
|
||||
is valid is not currently in scope.\n", bpt->number);
|
||||
bpt->enable = disabled;
|
||||
return;
|
||||
bpt->enable = disabled;
|
||||
return;
|
||||
}
|
||||
save_selected_frame = selected_frame;
|
||||
save_selected_frame_level = selected_frame_level;
|
||||
select_frame (fr, -1);
|
||||
}
|
||||
|
||||
value_free (bpt->val);
|
||||
|
|
@ -2639,6 +2771,9 @@ is valid is not currently in scope.\n", bpt->number);
|
|||
release_value (bpt->val);
|
||||
if (VALUE_LAZY (bpt->val))
|
||||
value_fetch_lazy (bpt->val);
|
||||
|
||||
if (save_selected_frame_level >= 0)
|
||||
select_frame (save_selected_frame, save_selected_frame_level);
|
||||
}
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue