1 /* Register note definitions. 2 Copyright (C) 2004-2013 Free Software Foundation, Inc. 3 4 This file is part of GCC. 5 6 GCC is free software; you can redistribute it and/or modify it under 7 the terms of the GNU General Public License as published by the Free 8 Software Foundation; either version 3, or (at your option) any later 9 version. 10 11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GCC; see the file COPYING3. If not see 18 <http://www.gnu.org/licenses/>. */ 19 20 /* This file defines all the codes that may appear on individual 21 EXPR_LIST rtxes in the REG_NOTES chain of an insn. The codes are 22 stored in the mode field of the EXPR_LIST. Source files define 23 DEF_REG_NOTE appropriately before including this file. */ 24 25 /* Shorthand. */ 26 #define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME) 27 28 /* REG_DEP_TRUE is used in scheduler dependencies lists to represent a 29 read-after-write dependency (i.e. a true data dependency). This is 30 here, not grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some 31 passes use a literal 0 for it. */ 32 REG_NOTE (DEP_TRUE) 33 34 /* The value in REG dies in this insn (i.e., it is not needed past 35 this insn). If REG is set in this insn, the REG_DEAD note may, 36 but need not, be omitted. */ 37 REG_NOTE (DEAD) 38 39 /* The REG is autoincremented or autodecremented in this insn. */ 40 REG_NOTE (INC) 41 42 /* Describes the insn as a whole; it says that the insn sets a 43 register to a constant value or to be equivalent to a memory 44 address. If the register is spilled to the stack then the constant 45 value should be substituted for it. The contents of the REG_EQUIV 46 is the constant value or memory address, which may be different 47 from the source of the SET although it has the same value. A 48 REG_EQUIV note may also appear on an insn which copies a register 49 parameter to a pseudo-register, if there is a memory address which 50 could be used to hold that pseudo-register throughout the function. */ 51 REG_NOTE (EQUIV) 52 53 /* Like REG_EQUIV except that the destination is only momentarily 54 equal to the specified rtx. Therefore, it cannot be used for 55 substitution; but it can be used for cse. */ 56 REG_NOTE (EQUAL) 57 58 /* The register is always nonnegative during the containing loop. 59 This is used in branches so that decrement and branch instructions 60 terminating on zero can be matched. There must be an insn pattern 61 in the md file named `decrement_and_branch_until_zero' or else this 62 will never be added to any instructions. */ 63 REG_NOTE (NONNEG) 64 65 /* Identifies a register set in this insn and never used. */ 66 REG_NOTE (UNUSED) 67 68 /* REG_CC_SETTER and REG_CC_USER link a pair of insns that set and use 69 CC0, respectively. Normally, these are required to be consecutive 70 insns, but we permit putting a cc0-setting insn in the delay slot 71 of a branch as long as only one copy of the insn exists. In that 72 case, these notes point from one to the other to allow code 73 generation to determine what any require information and to 74 properly update CC_STATUS. These notes are INSN_LISTs. */ 75 REG_NOTE (CC_SETTER) 76 REG_NOTE (CC_USER) 77 78 /* Points to a CODE_LABEL. Used by JUMP_INSNs to say that the CODE_LABEL 79 contained in the REG_LABEL_TARGET note is a possible jump target of 80 this insn. This note is an INSN_LIST. */ 81 REG_NOTE (LABEL_TARGET) 82 83 /* Points to a CODE_LABEL. Used by any insn to say that the CODE_LABEL 84 contained in the REG_LABEL_OPERAND note is used by the insn, but as an 85 operand, not as a jump target (though it may indirectly be a jump 86 target for a later jump insn). This note is an INSN_LIST. */ 87 REG_NOTE (LABEL_OPERAND) 88 89 /* REG_DEP_OUTPUT and REG_DEP_ANTI are used in scheduler dependencies lists 90 to represent write-after-write and write-after-read dependencies 91 respectively. */ 92 REG_NOTE (DEP_OUTPUT) 93 REG_NOTE (DEP_ANTI) 94 REG_NOTE (DEP_CONTROL) 95 96 /* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs. It has an 97 integer value. For jumps, it is the probability that this is a 98 taken branch. For calls, it is the probability that this call 99 won't return. */ 100 REG_NOTE (BR_PROB) 101 102 /* Attached to a call insn; indicates that the call is malloc-like and 103 that the pointer returned cannot alias anything else. */ 104 REG_NOTE (NOALIAS) 105 106 /* REG_BR_PRED is attached to JUMP_INSNs and CALL_INSNSs. It contains 107 CONCAT of two integer value. First specifies the branch predictor 108 that added the note, second specifies the predicted hitrate of 109 branch in the same format as REG_BR_PROB note uses. */ 110 REG_NOTE (BR_PRED) 111 112 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 113 for DWARF to interpret what they imply. The attached rtx is used 114 instead of intuition. */ 115 REG_NOTE (FRAME_RELATED_EXPR) 116 117 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 118 for FRAME_RELATED_EXPR intuition. The insn's first pattern must be 119 a SET, and the destination must be the CFA register. The attached 120 rtx is an expression that defines the CFA. In the simplest case, the 121 rtx could be just the stack_pointer_rtx; more common would be a PLUS 122 with a base register and a constant offset. In the most complicated 123 cases, this will result in a DW_CFA_def_cfa_expression with the rtx 124 expression rendered in a dwarf location expression. */ 125 REG_NOTE (CFA_DEF_CFA) 126 127 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 128 for FRAME_RELATED_EXPR intuition. This note adjusts the expression 129 from which the CFA is computed. The attached rtx defines a new CFA 130 expression, relative to the old CFA expression. This rtx must be of 131 the form (SET new-cfa-reg (PLUS old-cfa-reg const_int)). If the note 132 rtx is NULL, we use the first SET of the insn. */ 133 REG_NOTE (CFA_ADJUST_CFA) 134 135 /* Similar to FRAME_RELATED_EXPR, with the additional information that 136 this is a save to memory, i.e. will result in DW_CFA_offset or the 137 like. The pattern or the insn should be a simple store relative to 138 the CFA. */ 139 REG_NOTE (CFA_OFFSET) 140 141 /* Similar to FRAME_RELATED_EXPR, with the additional information that this 142 is a save to a register, i.e. will result in DW_CFA_register. The insn 143 or the pattern should be simple reg-reg move. */ 144 REG_NOTE (CFA_REGISTER) 145 146 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 147 for FRAME_RELATED_EXPR intuition. This is a save to memory, i.e. will 148 result in a DW_CFA_expression. The pattern or the insn should be a 149 store of a register to an arbitrary (non-validated) memory address. */ 150 REG_NOTE (CFA_EXPRESSION) 151 152 /* Attached to insns that are RTX_FRAME_RELATED_P, with the information 153 that this is a restore operation, i.e. will result in DW_CFA_restore 154 or the like. Either the attached rtx, or the destination of the insn's 155 first pattern is the register to be restored. */ 156 REG_NOTE (CFA_RESTORE) 157 158 /* Attached to insns that are RTX_FRAME_RELATED_P, marks insn that sets 159 vDRAP from DRAP. If vDRAP is a register, vdrap_reg is initalized 160 to the argument, if it is a MEM, it is ignored. */ 161 REG_NOTE (CFA_SET_VDRAP) 162 163 /* Attached to insns that are RTX_FRAME_RELATED_P, indicating a window 164 save operation, i.e. will result in a DW_CFA_GNU_window_save. 165 The argument is ignored. */ 166 REG_NOTE (CFA_WINDOW_SAVE) 167 168 /* Attached to insns that are RTX_FRAME_RELATED_P, marks the insn as 169 requiring that all queued information should be flushed *before* insn, 170 regardless of what is visible in the rtl. The argument is ignored. 171 This is normally used for a call instruction which is not exposed to 172 the rest of the compiler as a CALL_INSN. */ 173 REG_NOTE (CFA_FLUSH_QUEUE) 174 175 /* Indicates that REG holds the exception context for the function. 176 This context is shared by inline functions, so the code to acquire 177 the real exception context is delayed until after inlining. */ 178 REG_NOTE (EH_CONTEXT) 179 180 /* Indicates what exception region an INSN belongs in. This is used 181 to indicate what region to which a call may throw. REGION 0 182 indicates that a call cannot throw at all. REGION -1 indicates 183 that it cannot throw, nor will it execute a non-local goto. */ 184 REG_NOTE (EH_REGION) 185 186 /* Used by haifa-sched to save NOTE_INSN notes across scheduling. */ 187 REG_NOTE (SAVE_NOTE) 188 189 /* Indicates that a call does not return. */ 190 REG_NOTE (NORETURN) 191 192 /* Indicates that an indirect jump is a non-local goto instead of a 193 computed goto. */ 194 REG_NOTE (NON_LOCAL_GOTO) 195 196 /* Indicates that a jump crosses between hot and cold sections in a 197 (partitioned) assembly or .o file, and therefore should not be 198 reduced to a simpler jump by optimizations. */ 199 REG_NOTE (CROSSING_JUMP) 200 201 /* This kind of note is generated at each to `setjmp', and similar 202 functions that can return twice. */ 203 REG_NOTE (SETJMP) 204 205 /* This kind of note is generated at each transactional memory 206 builtin, to indicate we need to generate transaction restart 207 edges for this insn. */ 208 REG_NOTE (TM) 209 210 /* Indicates the cumulative offset of the stack pointer accounting 211 for pushed arguments. This will only be generated when 212 ACCUMULATE_OUTGOING_ARGS is false. */ 213 REG_NOTE (ARGS_SIZE) 214 215 /* Used for communication between IRA and caller-save.c, indicates 216 that the return value of a call can be used to reinitialize a 217 pseudo reg. */ 218 REG_NOTE (RETURNED) 219
