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225 lines
8.2 KiB
C
225 lines
8.2 KiB
C
/* Define per-register tables for data flow info and register allocation.
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Copyright (C) 1987, 1993, 1994, 1995, 1997, 1998 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "varray.h"
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#define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
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/* Get the number of consecutive hard regs required to hold the REG rtx R.
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When something may be an explicit hard reg, REG_SIZE is the only
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valid way to get this value. You cannot get it from the regno. */
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#define REG_SIZE(R) \
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((mode_size[(int) GET_MODE (R)] + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
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#ifndef SMALL_REGISTER_CLASSES
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#define SMALL_REGISTER_CLASSES 0
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#endif
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/* Maximum register number used in this function, plus one. */
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extern int max_regno;
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/* Maximum number of SCRATCH rtx's in each block of this function. */
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extern int max_scratch;
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/* Register information indexed by register number */
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typedef struct reg_info_def {
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/* fields set by reg_scan */
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int first_uid; /* UID of first insn to use (REG n) */
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int last_uid; /* UID of last insn to use (REG n) */
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int last_note_uid; /* UID of last note to use (REG n) */
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/* fields set by both reg_scan and flow_analysis */
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int sets; /* # of times (REG n) is set */
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/* fields set by flow_analysis */
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int refs; /* # of times (REG n) is used or set */
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int deaths; /* # of times (REG n) dies */
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int live_length; /* # of instructions (REG n) is live */
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int calls_crossed; /* # of calls (REG n) is live across */
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int basic_block; /* # of basic blocks (REG n) is used in */
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char changes_size; /* whether (SUBREG (REG n)) changes size */
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} reg_info;
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extern varray_type reg_n_info;
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extern unsigned int reg_n_max;
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/* Indexed by n, gives number of times (REG n) is used or set.
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References within loops may be counted more times. */
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#define REG_N_REFS(N) (VARRAY_REG (reg_n_info, N)->refs)
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/* Indexed by n, gives number of times (REG n) is set.
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??? both regscan and flow allocate space for this. We should settle
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on just copy. */
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#define REG_N_SETS(N) (VARRAY_REG (reg_n_info, N)->sets)
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/* Indexed by N, gives number of insns in which register N dies.
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Note that if register N is live around loops, it can die
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in transitions between basic blocks, and that is not counted here.
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So this is only a reliable indicator of how many regions of life there are
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for registers that are contained in one basic block. */
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#define REG_N_DEATHS(N) (VARRAY_REG (reg_n_info, N)->deaths)
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/* Indexed by N; says whether a pseudo register N was ever used
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within a SUBREG that changes the size of the reg. Some machines prohibit
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such objects to be in certain (usually floating-point) registers. */
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#define REG_CHANGES_SIZE(N) (VARRAY_REG (reg_n_info, N)->changes_size)
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/* Get the number of consecutive words required to hold pseudo-reg N. */
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#define PSEUDO_REGNO_SIZE(N) \
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((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \
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/ UNITS_PER_WORD)
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/* Get the number of bytes required to hold pseudo-reg N. */
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#define PSEUDO_REGNO_BYTES(N) \
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GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
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/* Get the machine mode of pseudo-reg N. */
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#define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
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/* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */
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#define REG_N_CALLS_CROSSED(N) (VARRAY_REG (reg_n_info, N)->calls_crossed)
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/* Total number of instructions at which (REG n) is live.
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The larger this is, the less priority (REG n) gets for
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allocation in a hard register (in global-alloc).
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This is set in flow.c and remains valid for the rest of the compilation
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of the function; it is used to control register allocation.
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local-alloc.c may alter this number to change the priority.
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Negative values are special.
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-1 is used to mark a pseudo reg which has a constant or memory equivalent
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and is used infrequently enough that it should not get a hard register.
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-2 is used to mark a pseudo reg for a parameter, when a frame pointer
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is not required. global.c makes an allocno for this but does
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not try to assign a hard register to it. */
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#define REG_LIVE_LENGTH(N) (VARRAY_REG (reg_n_info, N)->live_length)
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/* Vector of substitutions of register numbers,
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used to map pseudo regs into hardware regs.
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This can't be folded into reg_n_info without changing all of the
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machine dependent directories, since the reload functions
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in the machine dependent files access it. */
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extern short *reg_renumber;
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/* Vector indexed by hardware reg
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saying whether that reg is ever used. */
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extern char regs_ever_live[FIRST_PSEUDO_REGISTER];
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/* Vector indexed by hardware reg giving its name. */
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extern char *reg_names[FIRST_PSEUDO_REGISTER];
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/* For each hard register, the widest mode object that it can contain.
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This will be a MODE_INT mode if the register can hold integers. Otherwise
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it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
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register. */
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extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];
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/* Vector indexed by regno; gives uid of first insn using that reg.
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This is computed by reg_scan for use by cse and loop.
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It is sometimes adjusted for subsequent changes during loop,
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but not adjusted by cse even if cse invalidates it. */
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#define REGNO_FIRST_UID(N) (VARRAY_REG (reg_n_info, N)->first_uid)
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/* Vector indexed by regno; gives uid of last insn using that reg.
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This is computed by reg_scan for use by cse and loop.
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It is sometimes adjusted for subsequent changes during loop,
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but not adjusted by cse even if cse invalidates it.
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This is harmless since cse won't scan through a loop end. */
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#define REGNO_LAST_UID(N) (VARRAY_REG (reg_n_info, N)->last_uid)
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/* Similar, but includes insns that mention the reg in their notes. */
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#define REGNO_LAST_NOTE_UID(N) (VARRAY_REG (reg_n_info, N)->last_note_uid)
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/* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
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After rtl generation, it is 1 plus the largest register number used. */
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extern int reg_rtx_no;
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/* Vector indexed by regno; contains 1 for a register is considered a pointer.
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Reloading, etc. will use a pointer register rather than a non-pointer
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as the base register in an address, when there is a choice of two regs. */
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extern char *regno_pointer_flag;
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#define REGNO_POINTER_FLAG(REGNO) regno_pointer_flag[REGNO]
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extern int regno_pointer_flag_length;
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/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
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that have to go in the same hard reg. */
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extern rtx regs_may_share;
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/* Vector mapping pseudo regno into the REG rtx for that register.
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This is computed by reg_scan. */
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extern rtx *regno_reg_rtx;
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/* Flag set by local-alloc or global-alloc if they decide to allocate
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something in a call-clobbered register. */
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extern int caller_save_needed;
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/* Predicate to decide whether to give a hard reg to a pseudo which
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is referenced REFS times and would need to be saved and restored
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around a call CALLS times. */
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#ifndef CALLER_SAVE_PROFITABLE
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#define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS))
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#endif
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/* On most machines a register class is likely to be spilled if it
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only has one register. */
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#ifndef CLASS_LIKELY_SPILLED_P
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#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
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#endif
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/* Allocated in local_alloc. */
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/* A list of SCRATCH rtl allocated by local-alloc. */
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extern rtx *scratch_list;
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/* The basic block in which each SCRATCH is used. */
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extern int *scratch_block;
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/* The length of the arrays pointed to by scratch_block and scratch_list. */
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extern int scratch_list_length;
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/* Allocate reg_n_info tables */
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extern void allocate_reg_info PROTO((size_t, int, int));
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