path: root/gcc/df.h

/* Form lists of pseudo register references for autoinc optimization
   for GNU compiler.  This is part of flow optimization.
   Copyright (C) 1999, 2000, 2001, 2003, 2004, 2005, 2006
   Free Software Foundation, Inc.
   Originally contributed by Michael P. Hayes 
             (m.hayes@elec.canterbury.ac.nz, mhayes@redhat.com)
   Major rewrite contributed by Danny Berlin (dberlin@dberlin.org)
             and Kenneth Zadeck (zadeck@naturalbridge.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 2, 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 COPYING.  If not, write to the Free
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.  */

#ifndef GCC_DF_H
#define GCC_DF_H

#include "bitmap.h"
#include "basic-block.h"
#include "alloc-pool.h"

struct dataflow;
struct df;
struct df_problem;

/* Data flow problems.  All problems must have a unique here.  */ 
/* Scanning is not really a dataflow problem, but it is useful to have
   the basic block functions in the vector so that things get done in
   a uniform manner.  */
#define DF_SCAN  0 
#define DF_RU    1      /* Reaching Uses. */
#define DF_RD    2      /* Reaching Defs. */
#define DF_LR    3      /* Live Registers. */
#define DF_UR    4      /* Uninitialized Registers. */
#define DF_UREC  5      /* Uninitialized Registers with Early Clobber. */
#define DF_CHAIN 6      /* Def-Use and/or Use-Def Chains. */
#define DF_RI    7      /* Register Info. */
#define DF_LAST_PROBLEM_PLUS1 (DF_RI + 1)

/* Flags that control the building of chains.  */
#define DF_DU_CHAIN   1    /* Build DU chains.  */  
#define DF_UD_CHAIN   2    /* Build UD chains.  */


/* Dataflow direction.  */
enum df_flow_dir
  {
    DF_NONE,
    DF_FORWARD,
    DF_BACKWARD
  };

/* Function prototypes added to df_problem instance.  */

/* Allocate the problem specific data.  */
typedef void (*df_alloc_function) (struct dataflow *, bitmap);

/* This function is called if the problem has global data that needs
   to be cleared when ever the set of blocks changes.  The bitmap
   contains the set of blocks that may require special attention.
   This call is only made if some of the blocks are going to change.
   If everything is to be deleted, the wholesale deletion mechanisms
   apply. */
typedef void (*df_reset_function) (struct dataflow *, bitmap);

/* Free the basic block info.  Called from the block reordering code
   to get rid of the blocks that have been squished down.   */
typedef void (*df_free_bb_function) (struct dataflow *, basic_block, void *);

/* Local compute function.  */
typedef void (*df_local_compute_function) (struct dataflow *, bitmap, bitmap);

/* Init the solution specific data.  */
typedef void (*df_init_function) (struct dataflow *, bitmap);

/* Iterative dataflow function.  */
typedef void (*df_dataflow_function) (struct dataflow *, bitmap, bitmap, 
				   int *, int, bool);

/* Confluence operator for blocks with 0 out (or in) edges.  */
typedef void (*df_confluence_function_0) (struct dataflow *, basic_block);

/* Confluence operator for blocks with 1 or more out (or in) edges.  */
typedef void (*df_confluence_function_n) (struct dataflow *, edge);

/* Transfer function for blocks.  */
typedef bool (*df_transfer_function) (struct dataflow *, int);

/* Function to massage the information after the problem solving.  */
typedef void (*df_finalizer_function) (struct dataflow*, bitmap);

/* Function to free all of the problem specific datastructures.  */
typedef void (*df_free_function) (struct dataflow *);

/* Function to dump results to FILE.  */
typedef void (*df_dump_problem_function) (struct dataflow *, FILE *);

/* The static description of a dataflow problem to solve.  See above
   typedefs for doc for the function fields.  */

struct df_problem {
  /* The unique id of the problem.  This is used it index into
     df->defined_problems to make accessing the problem data easy.  */
  unsigned int id;                        
  enum df_flow_dir dir;			/* Dataflow direction.  */
  df_alloc_function alloc_fun;
  df_reset_function reset_fun;
  df_free_bb_function free_bb_fun;
  df_local_compute_function local_compute_fun;
  df_init_function init_fun;
  df_dataflow_function dataflow_fun;
  df_confluence_function_0 con_fun_0;
  df_confluence_function_n con_fun_n;
  df_transfer_function trans_fun;
  df_finalizer_function finalize_fun;
  df_free_function free_fun;
  df_dump_problem_function dump_fun;

  /* A dataflow problem that must be solved before this problem can be
     solved.  */
  struct df_problem *dependent_problem;
};


/* The specific instance of the problem to solve.  */
struct dataflow
{
  struct df *df;                        /* Instance of df we are working in.  */
  struct df_problem *problem;           /* The problem to be solved.  */

  /* Communication between iterative_dataflow and hybrid_search. */
  sbitmap visited, pending, considered; 

  /* Array indexed by bb->index, that contains basic block problem and
     solution specific information.  */
  void **block_info;
  unsigned int block_info_size;

  /* The pool to allocate the block_info from. */
  alloc_pool block_pool;                

  /* Other problem specific data that is not on a per basic block
     basis.  The structure is generally defined privately for the
     problem.  The exception being the scanning problem where it is
     fully public.  */
  void *problem_data;                  
};

/* One of these structures is allocated for every insn.  */
struct df_insn_info
{
  struct df_ref *defs;	        /* Head of insn-def chain.  */
  struct df_ref *uses;	        /* Head of insn-use chain.  */
  /* ???? The following luid field should be considered private so that
     we can change it on the fly to accommodate new insns?  */
  int luid;			/* Logical UID.  */
  bool contains_asm;            /* Contains an asm instruction.  */
};

/* Two of these structures are allocated for every pseudo reg, one for
   the uses and one for the defs.  */
struct df_reg_info
{
  struct df_ref *reg_chain;     /* Head of reg-use or def chain.  */
  unsigned int begin;           /* First def_index for this pseudo.  */
  unsigned int n_refs;          /* Number of refs or defs for this pseudo.  */
};


enum df_ref_type {DF_REF_REG_DEF, DF_REF_REG_USE, DF_REF_REG_MEM_LOAD,
		  DF_REF_REG_MEM_STORE};

#define DF_REF_TYPE_NAMES {"def", "use", "mem load", "mem store"}

enum df_ref_flags
  {
    /* Read-modify-write refs generate both a use and a def and
       these are marked with this flag to show that they are not
       independent.  */
    DF_REF_READ_WRITE = 1,

    /* This flag is set, if we stripped the subreg from the reference.
       In this case we must make conservative guesses, at what the
       outer mode was.  */
    DF_REF_STRIPPED = 2,
    
    /* If this flag is set, this is not a real definition/use, but an
       artificial one created to model always live registers, eh uses, etc.  */
    DF_REF_ARTIFICIAL = 4,


    /* If this flag is set for an artificial use or def, that ref
       logically happens at the top of the block.  If it is not set
       for an artificial use or def, that ref logically happens at the
       bottom of the block.  This is never set for regular refs.  */
    DF_REF_AT_TOP = 8,

    /* This flag is set if the use is inside a REG_EQUAL note.  */
    DF_REF_IN_NOTE = 16,

    /* This flag is set if this ref is really a clobber, and not a def.  */
    DF_REF_CLOBBER = 32,

    /* True if ref is dead (i.e. the next ref is a def or clobber or
       the end of the function.)  This is only valid the RI problem
       has been set in this df instance.  */
    DF_REF_DIES_AFTER_THIS_USE = 64
  };


/* Define a register reference structure.  One of these is allocated
   for every register reference (use or def).  Note some register
   references (e.g., post_inc, subreg) generate both a def and a use.  */
struct df_ref
{
  rtx reg;			/* The register referenced.  */
  unsigned int regno;           /* The register number referenced.  */
  basic_block bb;               /* Basic block containing the instruction. */

  /* Insn containing ref. This will be null if this is an artificial
     reference.  */
  rtx insn;
  rtx *loc;			/* The location of the reg.  */
  struct df_link *chain;	/* Head of def-use, use-def.  */
  unsigned int id;		/* Location in table.  */
  enum df_ref_type type;	/* Type of ref.  */
  enum df_ref_flags flags;	/* Various flags.  */

  /* For each regno, there are two chains of refs, one for the uses
     and one for the defs.  These chains go thru the refs themselves
     rather than using an external structure.  */
  struct df_ref *next_reg;     /* Next ref with same regno and type.  */
  struct df_ref *prev_reg;     /* Prev ref with same regno and type.  */

  /* Each insn has two lists, one for the uses and one for the
     defs. This is the next field in either of these chains. */
  struct df_ref *next_ref; 
  void *data;			/* The data assigned to it by user.  */
};

/* There are two kinds of links: */

/* This is used for def-use or use-def chains.  */
struct df_link
{
  struct df_ref *ref;
  struct df_link *next;
};

/* Two of these structures are allocated, one for the uses and one for
   the defs.  */
struct df_ref_info
{
  struct df_reg_info **regs;    /* Array indexed by pseudo regno. */
  unsigned int regs_size;       /* Size of currently allocated regs table.  */
  unsigned int regs_inited;     /* Number of regs with reg_infos allocated.  */
  struct df_ref **refs;         /* Ref table, indexed by id.  */
  unsigned int refs_size;       /* Size of currently allocated refs table.  */
  unsigned int bitmap_size;	/* Number of refs seen.  */

  /* True if refs table is organized so that every reference for a
     pseudo is contigious.  */
  bool refs_organized;
  /* True if the next refs should be added immediately or false to
     defer to later to reorganize the table.  */
  bool add_refs_inline; 
};


/*----------------------------------------------------------------------------
   Problem data for the scanning dataflow problem.  Unlike the other
   dataflow problems, the problem data for scanning is fully exposed and
   used by owners of the problem.
----------------------------------------------------------------------------*/

struct df
{

#define DF_HARD_REGS	     1	/* Mark hard registers.  */
#define DF_EQUIV_NOTES	     2	/* Mark uses present in EQUIV/EQUAL notes.  */
#define DF_SUBREGS	     4	/* Return subregs rather than the inner reg.  */

  int flags;			/* Indicates what's recorded.  */

  /* The set of problems to be solved is stored in two arrays.  In
     PROBLEMS_IN_ORDER, the problems are stored in the order that they
     are solved.  This is an internally dense array that may have
     nulls at the end of it.  In PROBLEMS_BY_INDEX, the problem is
     stored by the value in df_problem.id.  These are used to access
     the problem local data without having to search the first
     array.  */

  struct dataflow *problems_in_order [DF_LAST_PROBLEM_PLUS1]; 
  struct dataflow *problems_by_index [DF_LAST_PROBLEM_PLUS1]; 
  int num_problems_defined;

  /* Set after calls to df_scan_blocks, this contains all of the
     blocks that higher level problems must rescan before solving the
     dataflow equations.  If this is NULL, the blocks_to_analyze is
     used. */
  bitmap blocks_to_scan;

  /* If not NULL, the subset of blocks of the program to be considered
     for analysis.  */ 
  bitmap blocks_to_analyze;

  /* The following information is really the problem data for the
     scanning instance but it is used too often by the other problems
     to keep getting it from there.  */
  struct df_ref_info def_info;   /* Def info.  */
  struct df_ref_info use_info;   /* Use info.  */
  struct df_insn_info **insns;   /* Insn table, indexed by insn UID.  */
  unsigned int insns_size;       /* Size of insn table.  */
  bitmap hardware_regs_used;     /* The set of hardware registers used.  */
  bitmap entry_block_defs;       /* The set of hardware registers live on entry to the function.  */
  bitmap exit_block_uses;        /* The set of hardware registers used in exit block.  */
};

#define DF_SCAN_BB_INFO(DF, BB) (df_scan_get_bb_info((DF)->problems_by_index[DF_SCAN],(BB)->index))
#define DF_RU_BB_INFO(DF, BB) (df_ru_get_bb_info((DF)->problems_by_index[DF_RU],(BB)->index))
#define DF_RD_BB_INFO(DF, BB) (df_rd_get_bb_info((DF)->problems_by_index[DF_RD],(BB)->index))
#define DF_LR_BB_INFO(DF, BB) (df_lr_get_bb_info((DF)->problems_by_index[DF_LR],(BB)->index))
#define DF_UR_BB_INFO(DF, BB) (df_ur_get_bb_info((DF)->problems_by_index[DF_UR],(BB)->index))
#define DF_UREC_BB_INFO(DF, BB) (df_urec_get_bb_info((DF)->problems_by_index[DF_UREC],(BB)->index))

/* Most transformations that wish to use live register analysis will
   use these macros.  The DF_UPWARD_LIVE* macros are only half of the
   solution.  */
#define DF_LIVE_IN(DF, BB) (DF_UR_BB_INFO(DF, BB)->in) 
#define DF_LIVE_OUT(DF, BB) (DF_UR_BB_INFO(DF, BB)->out) 


/* Live in for register allocation also takes into account several other factors.  */
#define DF_RA_LIVE_IN(DF, BB) (DF_UREC_BB_INFO(DF, BB)->in) 
#define DF_RA_LIVE_OUT(DF, BB) (DF_UREC_BB_INFO(DF, BB)->out) 

/* These macros are currently used by only reg-stack since it is not
   tolerant of uninitialized variables.  This intolerance should be
   fixed because it causes other problems.  */ 
#define DF_UPWARD_LIVE_IN(DF, BB) (DF_LR_BB_INFO(DF, BB)->in) 
#define DF_UPWARD_LIVE_OUT(DF, BB) (DF_LR_BB_INFO(DF, BB)->out) 


/* Macros to access the elements within the ref structure.  */


#define DF_REF_REAL_REG(REF) (GET_CODE ((REF)->reg) == SUBREG \
				? SUBREG_REG ((REF)->reg) : ((REF)->reg))
#define DF_REF_REGNO(REF) ((REF)->regno)
#define DF_REF_REAL_LOC(REF) (GET_CODE ((REF)->reg) == SUBREG \
			        ? &SUBREG_REG ((REF)->reg) : ((REF)->loc))
#define DF_REF_REG(REF) ((REF)->reg)
#define DF_REF_LOC(REF) ((REF)->loc)
#define DF_REF_BB(REF) ((REF)->bb)
#define DF_REF_BBNO(REF) (DF_REF_BB (REF)->index)
#define DF_REF_INSN(REF) ((REF)->insn)
#define DF_REF_INSN_UID(REF) (INSN_UID ((REF)->insn))
#define DF_REF_TYPE(REF) ((REF)->type)
#define DF_REF_CHAIN(REF) ((REF)->chain)
#define DF_REF_ID(REF) ((REF)->id)
#define DF_REF_FLAGS(REF) ((REF)->flags)
#define DF_REF_NEXT_REG(REF) ((REF)->next_reg)
#define DF_REF_PREV_REG(REF) ((REF)->prev_reg)
#define DF_REF_NEXT_REF(REF) ((REF)->next_ref)
#define DF_REF_DATA(REF) ((REF)->data)

/* Macros to determine the reference type.  */

#define DF_REF_REG_DEF_P(REF) (DF_REF_TYPE (REF) == DF_REF_REG_DEF)
#define DF_REF_REG_USE_P(REF) ((REF) && ! DF_REF_REG_DEF_P (REF))
#define DF_REF_REG_MEM_STORE_P(REF) (DF_REF_TYPE (REF) == DF_REF_REG_MEM_STORE)
#define DF_REF_REG_MEM_LOAD_P(REF) (DF_REF_TYPE (REF) == DF_REF_REG_MEM_LOAD)
#define DF_REF_REG_MEM_P(REF) (DF_REF_REG_MEM_STORE_P (REF) \
                               || DF_REF_REG_MEM_LOAD_P (REF))

/* Macros to get the refs out of def_info or use_info refs table.  */
#define DF_DEFS_SIZE(DF) ((DF)->def_info.bitmap_size)
#define DF_DEFS_GET(DF,ID) ((DF)->def_info.refs[(ID)])
#define DF_DEFS_SET(DF,ID,VAL) ((DF)->def_info.refs[(ID)]=(VAL))
#define DF_USES_SIZE(DF) ((DF)->use_info.bitmap_size)
#define DF_USES_GET(DF,ID) ((DF)->use_info.refs[(ID)])
#define DF_USES_SET(DF,ID,VAL) ((DF)->use_info.refs[(ID)]=(VAL))

/* Macros to access the register information from scan dataflow record.  */

#define DF_REG_SIZE(DF) ((DF)->def_info.regs_inited)
#define DF_REG_DEF_GET(DF, REG) ((DF)->def_info.regs[(REG)])
#define DF_REG_DEF_SET(DF, REG, VAL) ((DF)->def_info.regs[(REG)]=(VAL))
#define DF_REG_USE_GET(DF, REG) ((DF)->use_info.regs[(REG)])
#define DF_REG_USE_SET(DF, REG, VAL) ((DF)->use_info.regs[(REG)]=(VAL))

/* Macros to access the elements within the reg_info structure table.  */

#define DF_REGNO_FIRST_DEF(DF, REGNUM) \
(DF_REG_DEF_GET(DF, REGNUM) ? DF_REG_DEF_GET(DF, REGNUM) : 0)
#define DF_REGNO_LAST_USE(DF, REGNUM) \
(DF_REG_USE_GET(DF, REGNUM) ? DF_REG_USE_GET(DF, REGNUM) : 0)

/* Macros to access the elements within the insn_info structure table.  */

#define DF_INSN_SIZE(DF) ((DF)->insns_size)
#define DF_INSN_GET(DF,INSN) ((DF)->insns[(INSN_UID(INSN))])
#define DF_INSN_SET(DF,INSN,VAL) ((DF)->insns[(INSN_UID (INSN))]=(VAL))
#define DF_INSN_CONTAINS_ASM(DF, INSN) (DF_INSN_GET(DF,INSN)->contains_asm)
#define DF_INSN_LUID(DF, INSN) (DF_INSN_GET(DF,INSN)->luid)
#define DF_INSN_DEFS(DF, INSN) (DF_INSN_GET(DF,INSN)->defs)
#define DF_INSN_USES(DF, INSN) (DF_INSN_GET(DF,INSN)->uses)

#define DF_INSN_UID_GET(DF,UID) ((DF)->insns[(UID)])
#define DF_INSN_UID_LUID(DF, INSN) (DF_INSN_UID_GET(DF,INSN)->luid)
#define DF_INSN_UID_DEFS(DF, INSN) (DF_INSN_UID_GET(DF,INSN)->defs)
#define DF_INSN_UID_USES(DF, INSN) (DF_INSN_UID_GET(DF,INSN)->uses)

/* This is a bitmap copy of regs_invalidated_by_call so that we can
   easily add it into bitmaps, etc. */ 

extern bitmap df_invalidated_by_call;

/* Initialize ur_in and ur_out as if all hard registers were partially
available.  */

/* The way that registers are processed, especially hard registers,
   changes as the compilation proceeds. These states are passed to
   df_set_state to control this processing.  */

#define DF_SCAN_INITIAL    1    /* Processing from beginning of rtl to
				   global-alloc.  */
#define DF_SCAN_GLOBAL     2    /* Processing before global
				   allocation.  */
#define DF_SCAN_POST_ALLOC 4    /* Processing after register
				   allocation.  */
extern int df_state;            /* Indicates where we are in the compilation.  */


/* One of these structures is allocated for every basic block.  */
struct df_scan_bb_info
{
  /* Defs at the start of a basic block that is the target of an
     exception edge.  */
  struct df_ref *artificial_defs;

  /* Uses of hard registers that are live at every block.  */
  struct df_ref *artificial_uses;
};


/* Reaching uses.  */
struct df_ru_bb_info 
{
  bitmap kill;
  bitmap sparse_kill;
  bitmap gen;
  bitmap in;
  bitmap out;
};


/* Reaching definitions.  */
struct df_rd_bb_info 
{
  bitmap kill;
  bitmap sparse_kill;
  bitmap gen;
  bitmap in;
  bitmap out;
};


/* Live registers.  */
struct df_lr_bb_info 
{
  bitmap def;
  bitmap use;
  bitmap in;
  bitmap out;
};


/* Uninitialized registers.  */
struct df_ur_bb_info 
{
  bitmap kill;
  bitmap gen;
  bitmap in;
  bitmap out;
};

/* Uninitialized registers.  */
struct df_urec_bb_info 
{
  bitmap earlyclobber;
  bitmap kill;
  bitmap gen;
  bitmap in;
  bitmap out;
};


#define df_finish(df) {df_finish1(df); df=NULL;}

/* Functions defined in df-core.c.  */

extern struct df *df_init (int);
extern struct dataflow *df_add_problem (struct df *, struct df_problem *);
extern void df_set_blocks (struct df*, bitmap);
extern void df_finish1 (struct df *);
extern void df_analyze (struct df *);
extern void df_compact_blocks (struct df *);
extern void df_bb_replace (struct df *, int, basic_block);
extern struct df_ref *df_bb_regno_last_use_find (struct df *, basic_block, unsigned int);
extern struct df_ref *df_bb_regno_first_def_find (struct df *, basic_block, unsigned int);
extern struct df_ref *df_bb_regno_last_def_find (struct df *, basic_block, unsigned int);
extern bool df_insn_regno_def_p (struct df *, rtx, unsigned int);
extern struct df_ref *df_find_def (struct df *, rtx, rtx);
extern bool df_reg_defined (struct df *, rtx, rtx);
extern struct df_ref *df_find_use (struct df *, rtx, rtx);
extern bool df_reg_used (struct df *, rtx, rtx);
extern void df_iterative_dataflow (struct dataflow *, bitmap, bitmap, int *, int, bool);
extern void df_dump (struct df *, FILE *);
extern void df_chain_dump (struct df *, struct df_link *, FILE *);
extern void df_refs_chain_dump (struct df *, struct df_ref *, bool, FILE *);
extern void df_regs_chain_dump (struct df *, struct df_ref *,  FILE *);
extern void df_insn_debug (struct df *, rtx, bool, FILE *);
extern void df_insn_debug_regno (struct df *, rtx, FILE *);
extern void df_regno_debug (struct df *, unsigned int, FILE *);
extern void df_ref_debug (struct df *, struct df_ref *, FILE *);
extern void debug_df_insn (rtx);
extern void debug_df_regno (unsigned int);
extern void debug_df_reg (rtx);
extern void debug_df_defno (unsigned int);
extern void debug_df_useno (unsigned int);
extern void debug_df_ref (struct df_ref *);
extern void debug_df_chain (struct df_link *);
/* An instance of df that can be shared between passes.  */
extern struct df *shared_df; 


/* Functions defined in df-problems.c. */

extern struct dataflow *df_get_dependent_problem (struct dataflow *);
extern struct df_link *df_chain_create (struct dataflow *, struct df_ref *, struct df_ref *);
extern void df_chain_unlink (struct dataflow *, struct df_ref *, struct df_link *);
extern void df_chain_copy (struct dataflow *, struct df_ref *, struct df_link *);
extern bitmap df_get_live_in (struct df *, basic_block);
extern bitmap df_get_live_out (struct df *, basic_block);
extern void df_grow_bb_info (struct dataflow *);
extern void df_chain_dump (struct df *, struct df_link *, FILE *);
extern void df_print_bb_index (basic_block bb, FILE *file);
extern struct dataflow *df_ru_add_problem (struct df *);
extern struct df_ru_bb_info *df_ru_get_bb_info (struct dataflow *, unsigned int);
extern struct dataflow *df_rd_add_problem (struct df *);
extern struct df_rd_bb_info *df_rd_get_bb_info (struct dataflow *, unsigned int);
extern struct dataflow *df_lr_add_problem (struct df *);
extern struct df_lr_bb_info *df_lr_get_bb_info (struct dataflow *, unsigned int);
extern struct dataflow *df_ur_add_problem (struct df *);
extern struct df_ur_bb_info *df_ur_get_bb_info (struct dataflow *, unsigned int);
extern struct dataflow *df_urec_add_problem (struct df *);
extern struct df_urec_bb_info *df_urec_get_bb_info (struct dataflow *, unsigned int);
extern struct dataflow *df_chain_add_problem (struct df *, int flags);
extern struct dataflow *df_ri_add_problem (struct df *);
extern int df_reg_lifetime (struct df *, rtx reg);


/* Functions defined in df-scan.c.  */

extern struct df_scan_bb_info *df_scan_get_bb_info (struct dataflow *, unsigned int);
extern struct dataflow *df_scan_add_problem (struct df *);
extern void df_rescan_blocks (struct df *, bitmap);
extern struct df_ref *df_ref_create (struct df *, rtx, rtx *, rtx,basic_block,enum df_ref_type, enum df_ref_flags);
extern struct df_ref *df_get_artificial_defs (struct df *, unsigned int);
extern struct df_ref *df_get_artificial_uses (struct df *, unsigned int);
extern void df_reg_chain_create (struct df_reg_info *, struct df_ref *);
extern struct df_ref *df_reg_chain_unlink (struct dataflow *, struct df_ref *);
extern void df_ref_remove (struct df *, struct df_ref *);
extern void df_insn_refs_delete (struct dataflow *, rtx);
extern void df_bb_refs_delete (struct dataflow *, int);
extern void df_refs_delete (struct dataflow *, bitmap);
extern void df_reorganize_refs (struct df_ref_info *);
extern void df_set_state (int);
extern void df_hard_reg_init (void);
extern bool df_read_modify_subreg_p (rtx);


#endif /* GCC_DF_H */