1/* Register note definitions. 2 Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 3 Free Software Foundation, Inc. 4 5This file is part of GCC. 6 7GCC is free software; you can redistribute it and/or modify it under 8the terms of the GNU General Public License as published by the Free 9Software Foundation; either version 3, or (at your option) any later 10version. 11 12GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13WARRANTY; without even the implied warranty of MERCHANTABILITY or 14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15for more details. 16 17You should have received a copy of the GNU General Public License 18along with GCC; see the file COPYING3. If not see 19<http://www.gnu.org/licenses/>. */ 20 21/* This file defines all the codes that may appear on individual 22 EXPR_LIST rtxes in the REG_NOTES chain of an insn. The codes are 23 stored in the mode field of the EXPR_LIST. Source files define 24 DEF_REG_NOTE appropriately before including this file. */ 25 26/* Shorthand. */ 27#define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME) 28 29/* REG_DEP_TRUE is used in scheduler dependencies lists to represent a 30 read-after-write dependency (i.e. a true data dependency). This is 31 here, not grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some 32 passes use a literal 0 for it. */ 33REG_NOTE (DEP_TRUE) 34 35/* The value in REG dies in this insn (i.e., it is not needed past 36 this insn). If REG is set in this insn, the REG_DEAD note may, 37 but need not, be omitted. */ 38REG_NOTE (DEAD) 39 40/* The REG is autoincremented or autodecremented in this insn. */ 41REG_NOTE (INC) 42 43/* Describes the insn as a whole; it says that the insn sets a 44 register to a constant value or to be equivalent to a memory 45 address. If the register is spilled to the stack then the constant 46 value should be substituted for it. The contents of the REG_EQUIV 47 is the constant value or memory address, which may be different 48 from the source of the SET although it has the same value. A 49 REG_EQUIV note may also appear on an insn which copies a register 50 parameter to a pseudo-register, if there is a memory address which 51 could be used to hold that pseudo-register throughout the function. */ 52REG_NOTE (EQUIV) 53 54/* Like REG_EQUIV except that the destination is only momentarily 55 equal to the specified rtx. Therefore, it cannot be used for 56 substitution; but it can be used for cse. */ 57REG_NOTE (EQUAL) 58 59/* The register is always nonnegative during the containing loop. 60 This is used in branches so that decrement and branch instructions 61 terminating on zero can be matched. There must be an insn pattern 62 in the md file named `decrement_and_branch_until_zero' or else this 63 will never be added to any instructions. */ 64REG_NOTE (NONNEG) 65 66/* Identifies a register set in this insn and never used. */ 67REG_NOTE (UNUSED) 68 69/* REG_CC_SETTER and REG_CC_USER link a pair of insns that set and use 70 CC0, respectively. Normally, these are required to be consecutive 71 insns, but we permit putting a cc0-setting insn in the delay slot 72 of a branch as long as only one copy of the insn exists. In that 73 case, these notes point from one to the other to allow code 74 generation to determine what any require information and to 75 properly update CC_STATUS. These notes are INSN_LISTs. */ 76REG_NOTE (CC_SETTER) 77REG_NOTE (CC_USER) 78 79/* Points to a CODE_LABEL. Used by JUMP_INSNs to say that the CODE_LABEL 80 contained in the REG_LABEL_TARGET note is a possible jump target of 81 this insn. This note is an INSN_LIST. */ 82REG_NOTE (LABEL_TARGET) 83 84/* Points to a CODE_LABEL. Used by any insn to say that the CODE_LABEL 85 contained in the REG_LABEL_OPERAND note is used by the insn, but as an 86 operand, not as a jump target (though it may indirectly be a jump 87 target for a later jump insn). This note is an INSN_LIST. */ 88REG_NOTE (LABEL_OPERAND) 89 90/* REG_DEP_OUTPUT and REG_DEP_ANTI are used in scheduler dependencies lists 91 to represent write-after-write and write-after-read dependencies 92 respectively. */ 93REG_NOTE (DEP_OUTPUT) 94REG_NOTE (DEP_ANTI) 95REG_NOTE (DEP_CONTROL) 96 97/* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs. It has an 98 integer value. For jumps, it is the probability that this is a 99 taken branch. For calls, it is the probability that this call 100 won't return. */ 101REG_NOTE (BR_PROB) 102 103/* Attached to a call insn; indicates that the call is malloc-like and 104 that the pointer returned cannot alias anything else. */ 105REG_NOTE (NOALIAS) 106 107/* REG_BR_PRED is attached to JUMP_INSNs and CALL_INSNSs. It contains 108 CONCAT of two integer value. First specifies the branch predictor 109 that added the note, second specifies the predicted hitrate of 110 branch in the same format as REG_BR_PROB note uses. */ 111REG_NOTE (BR_PRED) 112 113/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 114 for DWARF to interpret what they imply. The attached rtx is used 115 instead of intuition. */ 116REG_NOTE (FRAME_RELATED_EXPR) 117 118/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 119 for FRAME_RELATED_EXPR intuition. The insn's first pattern must be 120 a SET, and the destination must be the CFA register. The attached 121 rtx is an expression that defines the CFA. In the simplest case, the 122 rtx could be just the stack_pointer_rtx; more common would be a PLUS 123 with a base register and a constant offset. In the most complicated 124 cases, this will result in a DW_CFA_def_cfa_expression with the rtx 125 expression rendered in a dwarf location expression. */ 126REG_NOTE (CFA_DEF_CFA) 127 128/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 129 for FRAME_RELATED_EXPR intuition. This note adjusts the expression 130 from which the CFA is computed. The attached rtx defines a new CFA 131 expression, relative to the old CFA expression. This rtx must be of 132 the form (SET new-cfa-reg (PLUS old-cfa-reg const_int)). If the note 133 rtx is NULL, we use the first SET of the insn. */ 134REG_NOTE (CFA_ADJUST_CFA) 135 136/* Similar to FRAME_RELATED_EXPR, with the additional information that 137 this is a save to memory, i.e. will result in DW_CFA_offset or the 138 like. The pattern or the insn should be a simple store relative to 139 the CFA. */ 140REG_NOTE (CFA_OFFSET) 141 142/* Similar to FRAME_RELATED_EXPR, with the additional information that this 143 is a save to a register, i.e. will result in DW_CFA_register. The insn 144 or the pattern should be simple reg-reg move. */ 145REG_NOTE (CFA_REGISTER) 146 147/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 148 for FRAME_RELATED_EXPR intuition. This is a save to memory, i.e. will 149 result in a DW_CFA_expression. The pattern or the insn should be a 150 store of a register to an arbitrary (non-validated) memory address. */ 151REG_NOTE (CFA_EXPRESSION) 152 153/* Attached to insns that are RTX_FRAME_RELATED_P, with the information 154 that this is a restore operation, i.e. will result in DW_CFA_restore 155 or the like. Either the attached rtx, or the destination of the insn's 156 first pattern is the register to be restored. */ 157REG_NOTE (CFA_RESTORE) 158 159/* Attached to insns that are RTX_FRAME_RELATED_P, marks insn that sets 160 vDRAP from DRAP. If vDRAP is a register, vdrap_reg is initalized 161 to the argument, if it is a MEM, it is ignored. */ 162REG_NOTE (CFA_SET_VDRAP) 163 164/* Attached to insns that are RTX_FRAME_RELATED_P, indicating a window 165 save operation, i.e. will result in a DW_CFA_GNU_window_save. 166 The argument is ignored. */ 167REG_NOTE (CFA_WINDOW_SAVE) 168 169/* Attached to insns that are RTX_FRAME_RELATED_P, marks the insn as 170 requiring that all queued information should be flushed *before* insn, 171 regardless of what is visible in the rtl. The argument is ignored. 172 This is normally used for a call instruction which is not exposed to 173 the rest of the compiler as a CALL_INSN. */ 174REG_NOTE (CFA_FLUSH_QUEUE) 175 176/* Indicates that REG holds the exception context for the function. 177 This context is shared by inline functions, so the code to acquire 178 the real exception context is delayed until after inlining. */ 179REG_NOTE (EH_CONTEXT) 180 181/* Indicates what exception region an INSN belongs in. This is used 182 to indicate what region to which a call may throw. REGION 0 183 indicates that a call cannot throw at all. REGION -1 indicates 184 that it cannot throw, nor will it execute a non-local goto. */ 185REG_NOTE (EH_REGION) 186 187/* Used by haifa-sched to save NOTE_INSN notes across scheduling. */ 188REG_NOTE (SAVE_NOTE) 189 190/* Indicates that a call does not return. */ 191REG_NOTE (NORETURN) 192 193/* Indicates that an indirect jump is a non-local goto instead of a 194 computed goto. */ 195REG_NOTE (NON_LOCAL_GOTO) 196 197/* Indicates that a jump crosses between hot and cold sections in a 198 (partitioned) assembly or .o file, and therefore should not be 199 reduced to a simpler jump by optimizations. */ 200REG_NOTE (CROSSING_JUMP) 201 202/* This kind of note is generated at each to `setjmp', and similar 203 functions that can return twice. */ 204REG_NOTE (SETJMP) 205 206/* This kind of note is generated at each transactional memory 207 builtin, to indicate we need to generate transaction restart 208 edges for this insn. */ 209REG_NOTE (TM) 210 211/* Indicates the cumulative offset of the stack pointer accounting 212 for pushed arguments. This will only be generated when 213 ACCUMULATE_OUTGOING_ARGS is false. */ 214REG_NOTE (ARGS_SIZE) 215