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Re: [PATCH 1/3] Move computed value's frame id to piece_closure
On Fri, Nov 25, 2016 at 12:48:36PM +0100, Ulrich Weigand wrote:
> Yao Qi wrote:
>
> > + if (frame == NULL)
> > + c->frame_id = null_frame_id;
> > + else
> > + c->frame_id = get_frame_id (get_next_frame_sentinel_okay (frame));
> [...]
> > + struct frame_info *frame
> > + = frame_find_by_id (get_prev_frame_id_by_id (c->frame_id));
>
> I guess now that this is a separate field, there's no longer a reason
> to go via next-frame / prev-frame here. It looks like this was introduced
> when VALUE_FRAME_ID was changed to VALUE_NEXT_FRAME_ID, but this isn't
> really necessary for the piece logic here. I think this can simply be:
>
> c->frame_id = get_frame_id (frame);
> [...]
> struct frame_info *frame = frame_find_by_id (c->frame_id);
>
> instead.
>
> Otherwise, this looks good to me.
>
Patch below is pushed in.
--
Yao (齐尧)
>From ee40d8d45213caf0cfb63e603f0fd5a58532e751 Mon Sep 17 00:00:00 2001
From: Yao Qi <yao.qi@linaro.org>
Date: Mon, 28 Nov 2016 17:09:26 +0000
Subject: [PATCH] Move computed value's frame id to piece_closure
Nowadays, we set computed value's frame id, which is a misuse to me.
The computed value itself doesn't care about frame id, but function
value_computed_funcs (val)->read (or read_pieced_value) cares about
which frame the register is relative to, so 'struct piece_closure' is
a better place to fit frame id.
This patch adds a frame id in 'struct piece_closure', and use it
instead of using computed value's frame id.
gdb:
2016-11-28 Yao Qi <yao.qi@linaro.org>
* dwarf2loc.c (struct piece_closure) <frame_id>: New field.
(allocate_piece_closure): Add new parameter 'frame' and set
closure's frame_id field accordingly.
(read_pieced_value): Get frame from closure instead of value.
(dwarf2_evaluate_loc_desc_full): Remove code getting frame id.
Don't set value's frame id.
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 128f654..aaf88e4 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -1465,6 +1465,10 @@ struct piece_closure
/* The pieces themselves. */
struct dwarf_expr_piece *pieces;
+
+ /* Frame ID of frame to which a register value is relative, used
+ only by DWARF_VALUE_REGISTER. */
+ struct frame_id frame_id;
};
/* Allocate a closure for a value formed from separately-described
@@ -1473,7 +1477,7 @@ struct piece_closure
static struct piece_closure *
allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
int n_pieces, struct dwarf_expr_piece *pieces,
- int addr_size)
+ int addr_size, struct frame_info *frame)
{
struct piece_closure *c = XCNEW (struct piece_closure);
int i;
@@ -1483,6 +1487,10 @@ allocate_piece_closure (struct dwarf2_per_cu_data *per_cu,
c->n_pieces = n_pieces;
c->addr_size = addr_size;
c->pieces = XCNEWVEC (struct dwarf_expr_piece, n_pieces);
+ if (frame == NULL)
+ c->frame_id = null_frame_id;
+ else
+ c->frame_id = get_frame_id (frame);
memcpy (c->pieces, pieces, n_pieces * sizeof (struct dwarf_expr_piece));
for (i = 0; i < n_pieces; ++i)
@@ -1731,18 +1739,12 @@ read_pieced_value (struct value *v)
gdb_byte *contents;
struct piece_closure *c
= (struct piece_closure *) value_computed_closure (v);
- struct frame_info *frame;
size_t type_len;
size_t buffer_size = 0;
std::vector<gdb_byte> buffer;
int bits_big_endian
= gdbarch_bits_big_endian (get_type_arch (value_type (v)));
- /* VALUE_FRAME_ID is used instead of VALUE_NEXT_FRAME_ID here
- because FRAME is passed to get_frame_register_bytes(), which
- does its own "->next" operation. */
- frame = frame_find_by_id (VALUE_FRAME_ID (v));
-
if (value_type (v) != value_enclosing_type (v))
internal_error (__FILE__, __LINE__,
_("Should not be able to create a lazy value with "
@@ -1802,6 +1804,7 @@ read_pieced_value (struct value *v)
{
case DWARF_VALUE_REGISTER:
{
+ struct frame_info *frame = frame_find_by_id (c->frame_id);
struct gdbarch *arch = get_frame_arch (frame);
int gdb_regnum = dwarf_reg_to_regnum_or_error (arch, p->v.regno);
int optim, unavail;
@@ -2370,10 +2373,6 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
if (ctx.num_pieces > 0)
{
struct piece_closure *c;
- struct frame_id frame_id
- = frame == NULL
- ? null_frame_id
- : get_frame_id (get_next_frame_sentinel_okay (frame));
ULONGEST bit_size = 0;
int i;
@@ -2383,12 +2382,11 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
invalid_synthetic_pointer ();
c = allocate_piece_closure (per_cu, ctx.num_pieces, ctx.pieces,
- ctx.addr_size);
+ ctx.addr_size, frame);
/* We must clean up the value chain after creating the piece
closure but before allocating the result. */
do_cleanups (value_chain);
retval = allocate_computed_value (type, &pieced_value_funcs, c);
- VALUE_NEXT_FRAME_ID (retval) = frame_id;
set_value_offset (retval, byte_offset);
}
else