On Wed, Apr 27, 2016 at 10:03 AM, Pierre-Marie de Rodat
<dero...@adacore.com> wrote:
> Hello,
>
> As discussed on
> <https://gcc.gnu.org/ml/gcc-patches/2016-02/msg01708.html>, this change
> removes a field in the dw_loc_descr_node structure so we can get rid of
> the CHECKING_P macro usage.
>
> This field was used to perform consistency checks for frame offset in
> DWARF procedures. As a replacement, this commit turns the "visited
> nodes" set in resolve_args_picking_1 into a map that remembers for each
> dw_loc_descr_node the frame offset associated to it, so that the
> consistency check is still operational.
>
> Boostrapped and regtested on x86_64-linux. Ok to commit? Thank you in
Ok.
Thanks,
Richard.
> advance!
> ---
> gcc/dwarf2out.c | 37 +++++++++++++++++++------------------
> gcc/dwarf2out.h | 6 ------
> 2 files changed, 19 insertions(+), 24 deletions(-)
>
> diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
> index 0bbff87..463863d 100644
> --- a/gcc/dwarf2out.c
> +++ b/gcc/dwarf2out.c
> @@ -1325,9 +1325,6 @@ new_loc_descr (enum dwarf_location_atom op, unsigned
> HOST_WIDE_INT oprnd1,
> dw_loc_descr_ref descr = ggc_cleared_alloc<dw_loc_descr_node> ();
>
> descr->dw_loc_opc = op;
> -#if CHECKING_P
> - descr->dw_loc_frame_offset = -1;
> -#endif
> descr->dw_loc_oprnd1.val_class = dw_val_class_unsigned_const;
> descr->dw_loc_oprnd1.val_entry = NULL;
> descr->dw_loc_oprnd1.v.val_unsigned = oprnd1;
> @@ -15353,12 +15350,14 @@ is_handled_procedure_type (tree type)
> && int_size_in_bytes (type) <= DWARF2_ADDR_SIZE);
> }
>
> -/* Helper for resolve_args_picking. Stop when coming across VISITED nodes.
> */
> +/* Helper for resolve_args_picking: do the same but stop when coming across
> + visited nodes. For each node we visit, register in FRAME_OFFSETS the
> frame
> + offset *before* evaluating the corresponding operation. */
>
> static bool
> resolve_args_picking_1 (dw_loc_descr_ref loc, unsigned initial_frame_offset,
> struct dwarf_procedure_info *dpi,
> - hash_set<dw_loc_descr_ref> &visited)
> + hash_map<dw_loc_descr_ref, unsigned> &frame_offsets)
> {
> /* The "frame_offset" identifier is already used to name a macro... */
> unsigned frame_offset_ = initial_frame_offset;
> @@ -15366,19 +15365,18 @@ resolve_args_picking_1 (dw_loc_descr_ref loc,
> unsigned initial_frame_offset,
>
> for (l = loc; l != NULL;)
> {
> + bool existed;
> + unsigned &l_frame_offset = frame_offsets.get_or_insert (l, &existed);
> +
> /* If we already met this node, there is nothing to compute anymore.
> */
> - if (visited.add (l))
> + if (existed)
> {
> -#if CHECKING_P
> /* Make sure that the stack size is consistent wherever the
> execution
> flow comes from. */
> - gcc_assert ((unsigned) l->dw_loc_frame_offset == frame_offset_);
> -#endif
> + gcc_assert ((unsigned) l_frame_offset == frame_offset_);
> break;
> }
> -#if CHECKING_P
> - l->dw_loc_frame_offset = frame_offset_;
> -#endif
> + l_frame_offset = frame_offset_;
>
> /* If needed, relocate the picking offset with respect to the frame
> offset. */
> @@ -15601,7 +15599,7 @@ resolve_args_picking_1 (dw_loc_descr_ref loc,
> unsigned initial_frame_offset,
> {
> case DW_OP_bra:
> if (!resolve_args_picking_1 (l->dw_loc_next, frame_offset_, dpi,
> - visited))
> + frame_offsets))
> return false;
> /* Fall through... */
>
> @@ -15623,17 +15621,20 @@ resolve_args_picking_1 (dw_loc_descr_ref loc,
> unsigned initial_frame_offset,
>
> /* Make a DFS over operations reachable through LOC (i.e. follow branch
> operations) in order to resolve the operand of DW_OP_pick operations that
> - target DWARF procedure arguments (DPI). Stop at already visited nodes.
> - INITIAL_FRAME_OFFSET is the frame offset *before* LOC is executed. Return
> - if all relocations were successful. */
> + target DWARF procedure arguments (DPI). INITIAL_FRAME_OFFSET is the frame
> + offset *before* LOC is executed. Return if all relocations were
> + successful. */
>
> static bool
> resolve_args_picking (dw_loc_descr_ref loc, unsigned initial_frame_offset,
> struct dwarf_procedure_info *dpi)
> {
> - hash_set<dw_loc_descr_ref> visited;
> + /* Associate to all visited operations the frame offset *before* evaluating
> + this operation. */
> + hash_map<dw_loc_descr_ref, unsigned> frame_offsets;
>
> - return resolve_args_picking_1 (loc, initial_frame_offset, dpi, visited);
> + return resolve_args_picking_1 (loc, initial_frame_offset, dpi,
> + frame_offsets);
> }
>
> /* Try to generate a DWARF procedure that computes the same result as FNDECL.
> diff --git a/gcc/dwarf2out.h b/gcc/dwarf2out.h
> index 91b3d6b..abf0550 100644
> --- a/gcc/dwarf2out.h
> +++ b/gcc/dwarf2out.h
> @@ -239,12 +239,6 @@ struct GTY((chain_next ("%h.dw_loc_next")))
> dw_loc_descr_node {
> frame offset. */
> unsigned int frame_offset_rel : 1;
> int dw_loc_addr;
> -#if CHECKING_P
> - /* When translating a function into a DWARF procedure, contains the frame
> - offset *before* evaluating this operation. It is -1 when not yet
> - initialized. */
> - int dw_loc_frame_offset;
> -#endif
> dw_val_node dw_loc_oprnd1;
> dw_val_node dw_loc_oprnd2;
> };
> --
> 2.7.4
>
