valtrack.c File Reference

Data Structures
struct	rtx_subst_pair

Functions
static rtx	gen_lowpart_for_debug ()
static rtx	cleanup_auto_inc_dec ()
static rtx	propagate_for_debug_subst ()
void	propagate_for_debug (rtx insn, rtx last, rtx dest, rtx src, basic_block this_basic_block)
void	dead_debug_global_init ()
void	dead_debug_local_init (struct dead_debug_local *debug, bitmap used, struct dead_debug_global *global)
static dead_debug_global_entry *	dead_debug_global_find ()
static dead_debug_global_entry *	dead_debug_global_insert ()
static bool	dead_debug_global_replace_temp (struct dead_debug_global *global, df_ref use, unsigned int uregno, bitmap *pto_rescan)
static void	dead_debug_reset_uses (struct dead_debug_local *debug, struct dead_debug_use *head)
static void	dead_debug_promote_uses ()
void	dead_debug_local_finish ()
void	dead_debug_global_finish ()
void	dead_debug_add ()
int	dead_debug_insert_temp (struct dead_debug_local *debug, unsigned int uregno, rtx insn, enum debug_temp_where where)

---

Function Documentation

static rtx cleanup_auto_inc_dec ( )

static

   Replace auto-increment addressing modes with explicit operations to access
   the same addresses without modifying the corresponding registers.  

         SCRATCH must be shared because they represent distinct values.  

         Share clobbers of hard registers (like cc0), but do not share pseudo reg
         clobbers or clobbers of hard registers that originated as pseudos.
         This is needed to allow safe register renaming.  

     Copy the various flags, fields, and other information.  We assume
     that all fields need copying, and then clear the fields that should
     not be copied.  That is the sensible default behavior, and forces
     us to explicitly document why we are *not* copying a flag.  

     We do not copy the USED flag, which is used as a mark bit during
     walks over the RTL.  

     We do not copy FRAME_RELATED for INSNs.  

void dead_debug_add

(

)

   Add USE to DEBUG, or substitute it right away if it's a pseudo in
   the global substitution list.  USE must be a dead reference to
   UREGNO in a debug insn.  Create a bitmap for DEBUG as needed.  

     ??? If we dealt with split multi-registers below, we should set
     all registers for the used mode in case of hardware
     registers.  

References bitmap_bit_p(), bitmap_clear_bit(), dead_debug_local::global, dead_debug_local::head, dead_debug_global::used, and dead_debug_local::used.

Referenced by df_create_unused_note().

static dead_debug_global_entry* dead_debug_global_find ( )

static

   Locate the entry for REG in GLOBAL->htab.  

References hash_table< Descriptor, Allocator >::create(), dead_debug_global_entry::dtemp, hash_table< Descriptor, Allocator >::find_slot(), dead_debug_global::htab, hash_table< Descriptor, Allocator >::is_created(), and dead_debug_global_entry::reg.

Referenced by dead_debug_global_insert().

void dead_debug_global_finish

(

)

   Release GLOBAL->used unless it is the same as USED.  Release the
   mapping hash table if it was initialized.  

void dead_debug_global_init

(

)

   Initialize DEBUG to an empty list, and clear USED, if given.  

References dead_debug_local::global, dead_debug_local::head, dead_debug_local::to_rescan, dead_debug_global::used, and dead_debug_local::used.

static dead_debug_global_entry* dead_debug_global_insert ( )

static

   Insert an entry mapping REG to DTEMP in GLOBAL->htab.  

References bitmap_bit_p(), dead_debug_global_find(), dead_debug_global_entry::reg, and dead_debug_global::used.

static bool dead_debug_global_replace_temp ( struct dead_debug_global *  global, df_ref  use, unsigned int  uregno, bitmap *  pto_rescan  )

static

   If UREGNO, referenced by USE, is a pseudo marked as used in GLOBAL,
   replace it with with a USE of the debug temp recorded for it, and
   return TRUE.  Otherwise, just return FALSE.

   If PTO_RESCAN is given, instead of rescanning modified INSNs right
   away, add their UIDs to the bitmap, allocating one of *PTO_RESCAN
   is NULL.  

int dead_debug_insert_temp	(	struct dead_debug_local *	debug,
		unsigned int	uregno,
		rtx	insn,
		enum debug_temp_where	where
	)

   If UREGNO is referenced by any entry in DEBUG, emit a debug insn
   before or after INSN (depending on WHERE), that binds a (possibly
   global) debug temp to the widest-mode use of UREGNO, if WHERE is
   *_WITH_REG, or the value stored in UREGNO by INSN otherwise, and
   replace all uses of UREGNO in DEBUG with uses of the debug temp.
   INSN must be where UREGNO dies, if WHERE is *_BEFORE_*, or where it
   is set otherwise.  Return the number of debug insns emitted.  

     Move all uses of uregno from debug->head to uses, setting mode to
     the widest referenced mode.  

             If this loc has been changed e.g. to debug_expr already
             as part of a multi-register use, just drop it.  

     We may have dangling bits in debug->used for registers that were part
     of a multi-register use, one component of which has been reset.  

     Recover the expression INSN stores in REG.  

             Lose if the REG-setting insn is a CALL.  

         ??? Should we try to extract it from a PARALLEL?  

         Cool, it's the same REG, we can use SRC.  

             Hmm...  Something's fishy, we should be setting REG here.  

             If we're not overwriting all the hardware registers that
             setting REG in its mode would, we won't know what to bind
             the debug temp to.  ??? We could bind the debug_expr to a
             CONCAT or PARALLEL with the split multi-registers, and
             replace them as we found the corresponding sets.  

             Ok, it's the same (hardware) REG, but with a different
             mode, so SUBREG it.  

             We should be setting REG here.  Lose.  

             Lose if we're setting something other than the lowpart of
             REG.  

             If we're not overwriting all the hardware registers that
             setting REG in its mode would, we won't know what to bind
             the debug temp to.  

             Yay, we can use SRC, just adjust its mode.  

         Oh well, we're out of luck.  

         We couldn't figure out the value stored in REG, so reset all
         of its pending debug uses.  

     If there's a single (debug) use of an otherwise unused REG, and
     the debug use is not part of a larger expression, then it
     probably doesn't make sense to introduce a new debug temp.  

       Create DEBUG_EXPR (and DEBUG_EXPR_DECL).  

     Emit a debug bind insn before the insn in which reg dies.  

     Adjust all uses.  

         ??? Should we simplify subreg of subreg?  

References dead_debug_use::next, and dead_debug_use::use.

Referenced by df_create_unused_note().

void dead_debug_local_finish

(

)

   Reset all debug insns with pending uses.  Release the bitmap in it,
   unless it is USED.  USED must be the same bitmap passed to
   dead_debug_local_init.  

void dead_debug_local_init	(	struct dead_debug_local *	debug,
		bitmap	used,
		struct dead_debug_global *	global
	)

   Initialize DEBUG to an empty list, and clear USED, if given.  Link
   back to GLOBAL, if given, and bring in used bits from it.  

Referenced by gate_ud_dce().

static void dead_debug_promote_uses ( )

static

   Promote pending local uses of pseudos in DEBUG to global
   substitutions.  Uses of non-pseudos are left alone for
   resetting.  

         Tentatively remove the USE from the list.  

static void dead_debug_reset_uses ( struct dead_debug_local *  debug, struct dead_debug_use *  head  )

static

   Reset all debug uses in HEAD, and clear DEBUG->to_rescan bits of
   each reset insn.  DEBUG is not otherwise modified.  If HEAD is
   DEBUG->head, DEBUG->head will be set to NULL at the end.
   Otherwise, entries from DEBUG->head that pertain to reset insns
   will be removed, and only then rescanned.  

static rtx gen_lowpart_for_debug ( )

static

@verbatim 

Infrastructure for tracking user variable locations and values throughout compilation. Copyright (C) 2010-2013 Free Software Foundation, Inc. Contributed by Alexandre Oliva aoliv.nosp@m.a@re.nosp@m.dhat..nosp@m.com.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see http://www.gnu.org/licenses/.

   gen_lowpart_no_emit hook implementation for DEBUG_INSNs.  In DEBUG_INSNs,
   all lowpart SUBREGs are valid, despite what the machine requires for
   instructions.  

void propagate_for_debug	(	rtx	insn,
		rtx	last,
		rtx	dest,
		rtx	src,
		basic_block	this_basic_block
	)

   Replace all the occurrences of DEST with SRC in DEBUG_INSNs between INSN
   and LAST, not including INSN, but including LAST.  Also stop at the end
   of THIS_BASIC_BLOCK.  

static rtx propagate_for_debug_subst ( )

static

   DATA points to an rtx_subst_pair.  Return the value that should be
   substituted.