Ping - RE: [PATCH] Add target hook to override DWARF2 frame register size

[Matthew Fortune]

Ping.

Thanks, 
Matthew

> Sent: 07 August 2014 07:21
> > Please don't add target macros. Add a hook if you must, but we're
> > supposed to remove target macros, not add new ones :-)
> 
> Thanks Steven, I wasn't sure if there were still things that were
> acceptable as macros. There's a lot to get rid of still.
> 
> Updated patch using a target hook. I've opted to move the logic
> which handles part clobbered registers into the default implementation
> as that seemed natural. I have no real preference if others feel that
> is the wrong thing to do. This will be used by an up-coming patch for
> MIPS O32 ABI extensions.
> 
> Bootstrapped and regtested on x86_64-linux-gnu.
> 
> Thanks,
> Matthew
> 
> gcc/
> 	* target.def (TARGET_DWARF_FRAME_REG_MODE): New target hook.
> 	* targhooks.c (default_dwarf_frame_reg_mode): New function.
> 	* targhooks.h (default_dwarf_frame_reg_mode): New prototype.
> 	* doc/tm.texi.in (TARGET_DWARF_FRAME_REG_MODE): Document.
> 	* doc/tm.texi: Regenerate.
> 	* dwarf2cfi.c (expand_builtin_init_dwarf_reg_sizes): Abstract mode
> 	selection logic to default_dwarf_frame_reg_mode.
> ---
>  gcc/doc/tm.texi    |  7 +++++++
>  gcc/doc/tm.texi.in |  2 ++
>  gcc/dwarf2cfi.c    |  4 +---
>  gcc/target.def     | 11 +++++++++++
>  gcc/targhooks.c    | 13 +++++++++++++
>  gcc/targhooks.h    |  1 +
>  6 files changed, 35 insertions(+), 3 deletions(-)
> 
> diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
> index dd72b98..aa92ce4 100644
> --- a/gcc/doc/tm.texi.in
> +++ b/gcc/doc/tm.texi.in
> @@ -6604,6 +6604,8 @@ the target supports DWARF 2 frame unwind
> information.
> 
>  @hook TARGET_DWARF_REGISTER_SPAN
> 
> +@hook TARGET_DWARF_FRAME_REG_MODE
> +
>  @hook TARGET_INIT_DWARF_REG_SIZES_EXTRA
> 
>  @hook TARGET_ASM_TTYPE
> diff --git a/gcc/dwarf2cfi.c b/gcc/dwarf2cfi.c
> index 85cfb60..a673106 100644
> --- a/gcc/dwarf2cfi.c
> +++ b/gcc/dwarf2cfi.c
> @@ -271,11 +271,9 @@ expand_builtin_init_dwarf_reg_sizes (tree address)
>        if (rnum < DWARF_FRAME_REGISTERS)
>  	{
>  	  HOST_WIDE_INT offset = rnum * GET_MODE_SIZE (mode);
> -	  enum machine_mode save_mode = reg_raw_mode[i];
>  	  HOST_WIDE_INT size;
> +	  enum machine_mode save_mode = targetm.dwarf_frame_reg_mode (i);
> 
> -	  if (HARD_REGNO_CALL_PART_CLOBBERED (i, save_mode))
> -	    save_mode = choose_hard_reg_mode (i, 1, true);
>  	  if (dnum == DWARF_FRAME_RETURN_COLUMN)
>  	    {
>  	      if (save_mode == VOIDmode)
> diff --git a/gcc/target.def b/gcc/target.def
> index 3a41db1..d5aba51 100644
> --- a/gcc/target.def
> +++ b/gcc/target.def
> @@ -3216,6 +3216,17 @@ If not defined, the default is to return
> @code{NULL_RTX}.",
>   rtx, (rtx reg),
>   hook_rtx_rtx_null)
> 
> +/* Given a register return the mode of the corresponding DWARF frame
> +   register.  */
> +DEFHOOK
> +(dwarf_frame_reg_mode,
> + "Given a register, this hook should return the mode which the\n\
> +corresponding Dwarf frame register should have.  This is normally\n\
> +used to return a smaller mode than the raw mode to prevent call\n\
> +clobbered parts of a register altering the frame register size.",
> + enum machine_mode, (int regno),
> + default_dwarf_frame_reg_mode)
> +
>  /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
>     entries not corresponding directly to registers below
>     FIRST_PSEUDO_REGISTER, this hook should generate the necessary
> diff --git a/gcc/targhooks.c b/gcc/targhooks.c
> index 0f27a5a..765bf3b 100644
> --- a/gcc/targhooks.c
> +++ b/gcc/targhooks.c
> @@ -1456,6 +1456,19 @@ default_debug_unwind_info (void)
>    return UI_NONE;
>  }
> 
> +/* Determine the correct mode for a Dwarf frame register that
> represents
> +   register REGNO.  */
> +
> +enum machine_mode
> +default_dwarf_frame_reg_mode (int regno)
> +{
> +  enum machine_mode save_mode = reg_raw_mode[regno];
> +
> +  if (HARD_REGNO_CALL_PART_CLOBBERED (regno, save_mode))
> +    save_mode = choose_hard_reg_mode (regno, 1, true);
> +  return save_mode;
> +}
> +
>  /* To be used by targets where reg_raw_mode doesn't return the right
>     mode for registers used in apply_builtin_return and
> apply_builtin_arg.  */
> 
> diff --git a/gcc/targhooks.h b/gcc/targhooks.h
> index 4be33f8..fa88679 100644
> --- a/gcc/targhooks.h
> +++ b/gcc/targhooks.h
> @@ -194,6 +194,7 @@ extern int default_label_align_max_skip (rtx);
>  extern int default_jump_align_max_skip (rtx);
>  extern section * default_function_section(tree decl, enum
> node_frequency freq,
>  					  bool startup, bool exit);
> +extern enum machine_mode default_dwarf_frame_reg_mode (int);
>  extern enum machine_mode default_get_reg_raw_mode (int);
>  extern bool default_keep_leaf_when_profiled ();
> 
> --
> 1.9.4