Ping^2 - RE: [PATCH] Add target hook to override DWARF2 frame register size

Matthew Fortune Matthew.Fortune@imgtec.com
Tue Sep 2 08:59:00 GMT 2014


Ping^2

Added Jason as maintainer for dwarf related things.

This hook will be used in the following patch:
https://gcc.gnu.org/ml/gcc-patches/2014-08/msg02172.html

Thanks,
Matthew

> 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


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