1 | /* Define per-register tables for data flow info and register allocation. |
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2 | Copyright (C) 1987, 1993, 1994 Free Software Foundation, Inc. |
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3 | |
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4 | This file is part of GNU CC. |
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5 | |
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6 | GNU CC is free software; you can redistribute it and/or modify |
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7 | it under the terms of the GNU General Public License as published by |
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8 | the Free Software Foundation; either version 2, or (at your option) |
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9 | any later version. |
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10 | |
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11 | GNU CC is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | GNU General Public License for more details. |
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15 | |
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16 | You should have received a copy of the GNU General Public License |
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17 | along with GNU CC; see the file COPYING. If not, write to |
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18 | the Free Software Foundation, 59 Temple Place - Suite 330, |
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19 | Boston, MA 02111-1307, USA. */ |
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20 | |
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21 | |
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22 | |
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23 | #define REG_BYTES(R) mode_size[(int) GET_MODE (R)] |
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24 | |
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25 | /* Get the number of consecutive hard regs required to hold the REG rtx R. |
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26 | When something may be an explicit hard reg, REG_SIZE is the only |
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27 | valid way to get this value. You cannot get it from the regno. */ |
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28 | |
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29 | #define REG_SIZE(R) \ |
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30 | ((mode_size[(int) GET_MODE (R)] + UNITS_PER_WORD - 1) / UNITS_PER_WORD) |
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31 | |
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32 | /* Maximum register number used in this function, plus one. */ |
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33 | |
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34 | extern int max_regno; |
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35 | |
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36 | /* Maximum number of SCRATCH rtx's in each block of this function. */ |
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37 | |
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38 | extern int max_scratch; |
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39 | |
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40 | /* Indexed by n, gives number of times (REG n) is used or set. |
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41 | References within loops may be counted more times. */ |
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42 | |
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43 | extern int *reg_n_refs; |
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44 | |
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45 | /* Indexed by n, gives number of times (REG n) is set. */ |
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46 | |
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47 | extern short *reg_n_sets; |
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48 | |
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49 | /* Indexed by N, gives number of insns in which register N dies. |
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50 | Note that if register N is live around loops, it can die |
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51 | in transitions between basic blocks, and that is not counted here. |
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52 | So this is only a reliable indicator of how many regions of life there are |
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53 | for registers that are contained in one basic block. */ |
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54 | |
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55 | extern short *reg_n_deaths; |
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56 | |
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57 | /* Indexed by N; says whether a pseudo register N was ever used |
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58 | within a SUBREG that changes the size of the reg. Some machines prohibit |
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59 | such objects to be in certain (usually floating-point) registers. */ |
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60 | |
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61 | extern char *reg_changes_size; |
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62 | |
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63 | /* Get the number of consecutive words required to hold pseudo-reg N. */ |
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64 | |
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65 | #define PSEUDO_REGNO_SIZE(N) \ |
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66 | ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \ |
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67 | / UNITS_PER_WORD) |
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68 | |
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69 | /* Get the number of bytes required to hold pseudo-reg N. */ |
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70 | |
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71 | #define PSEUDO_REGNO_BYTES(N) \ |
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72 | GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) |
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73 | |
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74 | /* Get the machine mode of pseudo-reg N. */ |
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75 | |
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76 | #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N]) |
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77 | |
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78 | /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */ |
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79 | |
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80 | extern int *reg_n_calls_crossed; |
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81 | |
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82 | /* Total number of instructions at which (REG n) is live. |
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83 | The larger this is, the less priority (REG n) gets for |
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84 | allocation in a hard register (in global-alloc). |
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85 | This is set in flow.c and remains valid for the rest of the compilation |
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86 | of the function; it is used to control register allocation. |
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87 | |
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88 | local-alloc.c may alter this number to change the priority. |
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89 | |
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90 | Negative values are special. |
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91 | -1 is used to mark a pseudo reg which has a constant or memory equivalent |
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92 | and is used infrequently enough that it should not get a hard register. |
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93 | -2 is used to mark a pseudo reg for a parameter, when a frame pointer |
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94 | is not required. global.c makes an allocno for this but does |
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95 | not try to assign a hard register to it. */ |
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96 | |
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97 | extern int *reg_live_length; |
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98 | |
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99 | /* Vector of substitutions of register numbers, |
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100 | used to map pseudo regs into hardware regs. */ |
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101 | |
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102 | extern short *reg_renumber; |
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103 | |
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104 | /* Vector indexed by hardware reg |
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105 | saying whether that reg is ever used. */ |
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106 | |
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107 | extern char regs_ever_live[FIRST_PSEUDO_REGISTER]; |
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108 | |
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109 | /* Vector indexed by hardware reg giving its name. */ |
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110 | |
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111 | extern char *reg_names[FIRST_PSEUDO_REGISTER]; |
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112 | |
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113 | /* For each hard register, the widest mode object that it can contain. |
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114 | This will be a MODE_INT mode if the register can hold integers. Otherwise |
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115 | it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the |
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116 | register. */ |
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117 | |
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118 | extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER]; |
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119 | |
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120 | /* Vector indexed by regno; gives uid of first insn using that reg. |
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121 | This is computed by reg_scan for use by cse and loop. |
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122 | It is sometimes adjusted for subsequent changes during loop, |
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123 | but not adjusted by cse even if cse invalidates it. */ |
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124 | |
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125 | extern int *regno_first_uid; |
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126 | |
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127 | /* Vector indexed by regno; gives uid of last insn using that reg. |
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128 | This is computed by reg_scan for use by cse and loop. |
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129 | It is sometimes adjusted for subsequent changes during loop, |
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130 | but not adjusted by cse even if cse invalidates it. |
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131 | This is harmless since cse won't scan through a loop end. */ |
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132 | |
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133 | extern int *regno_last_uid; |
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134 | |
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135 | /* Similar, but includes insns that mention the reg in their notes. */ |
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136 | |
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137 | extern int *regno_last_note_uid; |
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138 | |
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139 | /* Vector indexed by regno; contains 1 for a register is considered a pointer. |
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140 | Reloading, etc. will use a pointer register rather than a non-pointer |
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141 | as the base register in an address, when there is a choice of two regs. */ |
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142 | |
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143 | extern char *regno_pointer_flag; |
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144 | #define REGNO_POINTER_FLAG(REGNO) regno_pointer_flag[REGNO] |
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145 | |
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146 | /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers |
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147 | that have to go in the same hard reg. */ |
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148 | extern rtx regs_may_share; |
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149 | |
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150 | /* Vector mapping pseudo regno into the REG rtx for that register. |
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151 | This is computed by reg_scan. */ |
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152 | |
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153 | extern rtx *regno_reg_rtx; |
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154 | |
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155 | /* Flag set by local-alloc or global-alloc if they decide to allocate |
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156 | something in a call-clobbered register. */ |
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157 | |
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158 | extern int caller_save_needed; |
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159 | |
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160 | /* Predicate to decide whether to give a hard reg to a pseudo which |
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161 | is referenced REFS times and would need to be saved and restored |
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162 | around a call CALLS times. */ |
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163 | |
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164 | #ifndef CALLER_SAVE_PROFITABLE |
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165 | #define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS)) |
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166 | #endif |
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167 | |
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168 | /* Allocated in local_alloc. */ |
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169 | |
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170 | /* A list of SCRATCH rtl allocated by local-alloc. */ |
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171 | extern rtx *scratch_list; |
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172 | /* The basic block in which each SCRATCH is used. */ |
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173 | extern int *scratch_block; |
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174 | /* The length of the arrays pointed to by scratch_block and scratch_list. */ |
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175 | extern int scratch_list_length; |
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