1 /* Register note definitions. 2 Copyright (C) 2004, 2005, 2006, 2007, 2008 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 95 /* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs. It has an 96 integer value. For jumps, it is the probability that this is a 97 taken branch. For calls, it is the probability that this call 98 won't return. */ 99 REG_NOTE (BR_PROB) 100 101 /* REG_VALUE_PROFILE is attached when the profile is read in to an 102 insn before that the code to profile the value is inserted. It 103 contains the results of profiling. */ 104 REG_NOTE (VALUE_PROFILE) 105 106 /* Attached to a call insn; indicates that the call is malloc-like and 107 that the pointer returned cannot alias anything else. */ 108 REG_NOTE (NOALIAS) 109 110 /* REG_BR_PRED is attached to JUMP_INSNs and CALL_INSNSs. It contains 111 CONCAT of two integer value. First specifies the branch predictor 112 that added the note, second specifies the predicted hitrate of 113 branch in the same format as REG_BR_PROB note uses. */ 114 REG_NOTE (BR_PRED) 115 116 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 117 for DWARF to interpret what they imply. The attached rtx is used 118 instead of intuition. */ 119 REG_NOTE (FRAME_RELATED_EXPR) 120 121 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 122 for FRAME_RELATED_EXPR intuition. The insn's first pattern must be 123 a SET, and the destination must be the CFA register. The attached 124 rtx is an expression that defines the CFA. In the simplest case, the 125 rtx could be just the stack_pointer_rtx; more common would be a PLUS 126 with a base register and a constant offset. In the most complicated 127 cases, this will result in a DW_CFA_def_cfa_expression with the rtx 128 expression rendered in a dwarf location expression. */ 129 REG_NOTE (CFA_DEF_CFA) 130 131 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 132 for FRAME_RELATED_EXPR intuition. This note adjusts the expression 133 from which the CFA is computed. The attached rtx defines a new CFA 134 expression, relative to the old CFA expression. This rtx must be of 135 the form (SET new-cfa-reg (PLUS old-cfa-reg const_int)). If the note 136 rtx is NULL, we use the first SET of the insn. */ 137 REG_NOTE (CFA_ADJUST_CFA) 138 139 /* Similar to FRAME_RELATED_EXPR, with the additional information that 140 this is a save to memory, i.e. will result in DW_CFA_offset or the 141 like. The pattern or the insn should be a simple store relative to 142 the CFA. */ 143 REG_NOTE (CFA_OFFSET) 144 145 /* Similar to FRAME_RELATED_EXPR, with the additional information that this 146 is a save to a register, i.e. will result in DW_CFA_register. The insn 147 or the pattern should be simple reg-reg move. */ 148 REG_NOTE (CFA_REGISTER) 149 150 /* Attached to insns that are RTX_FRAME_RELATED_P, with the information 151 that this is a restore operation, i.e. will result in DW_CFA_restore 152 or the like. Either the attached rtx, or the destination of the insn's 153 first pattern is the register to be restored. */ 154 REG_NOTE (CFA_RESTORE) 155 156 /* Indicates that REG holds the exception context for the function. 157 This context is shared by inline functions, so the code to acquire 158 the real exception context is delayed until after inlining. */ 159 REG_NOTE (EH_CONTEXT) 160 161 /* Indicates what exception region an INSN belongs in. This is used 162 to indicate what region to which a call may throw. REGION 0 163 indicates that a call cannot throw at all. REGION -1 indicates 164 that it cannot throw, nor will it execute a non-local goto. */ 165 REG_NOTE (EH_REGION) 166 167 /* Used by haifa-sched to save NOTE_INSN notes across scheduling. */ 168 REG_NOTE (SAVE_NOTE) 169 170 /* Indicates that a call does not return. */ 171 REG_NOTE (NORETURN) 172 173 /* Indicates that an indirect jump is a non-local goto instead of a 174 computed goto. */ 175 REG_NOTE (NON_LOCAL_GOTO) 176 177 /* Indicates that a jump crosses between hot and cold sections in a 178 (partitioned) assembly or .o file, and therefore should not be 179 reduced to a simpler jump by optimizations. */ 180 REG_NOTE (CROSSING_JUMP) 181 182 /* This kind of note is generated at each to `setjmp', and similar 183 functions that can return twice. */ 184 REG_NOTE (SETJMP) 185
