gcc/reg-notes.def

   1 /* Register note definitions.
   2    Copyright (C) 2004-2016 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, INSN_LIST and INT_LIST rtxes in the REG_NOTES chain of an insn.
  22    The codes are stored in the mode field of the rtx.  Source files
  23    define 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 (in an INT_LIST).  For jumps, it is the probability
  98    that this is a taken branch.  For calls, it is the probability that
  99    this call 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 what exception region an INSN belongs in.  This is used
 176    to indicate what region to which a call may throw.  REGION 0
 177    indicates that a call cannot throw at all.  REGION -1 indicates
 178    that it cannot throw, nor will it execute a non-local goto.  */
 179 REG_NOTE (EH_REGION)
 180
 181 /* Used by haifa-sched to save NOTE_INSN notes across scheduling.  */
 182 REG_NOTE (SAVE_NOTE)
 183
 184 /* Indicates that a call does not return.  */
 185 REG_NOTE (NORETURN)
 186
 187 /* Indicates that an indirect jump is a non-local goto instead of a
 188    computed goto.  */
 189 REG_NOTE (NON_LOCAL_GOTO)
 190
 191 /* This kind of note is generated at each to `setjmp', and similar
 192    functions that can return twice.  */
 193 REG_NOTE (SETJMP)
 194
 195 /* This kind of note is generated at each transactional memory
 196    builtin, to indicate we need to generate transaction restart
 197    edges for this insn.  */
 198 REG_NOTE (TM)
 199
 200 /* Indicates the cumulative offset of the stack pointer accounting
 201    for pushed arguments.  This will only be generated when
 202    ACCUMULATE_OUTGOING_ARGS is false.  */
 203 REG_NOTE (ARGS_SIZE)
 204
 205 /* Used for communication between IRA and caller-save.c, indicates
 206    that the return value of a call can be used to reinitialize a
 207    pseudo reg.  */
 208 REG_NOTE (RETURNED)
 209
 210 /* Used to mark a call with the function decl called by the call.
 211    The decl might not be available in the call due to splitting of the call
 212    insn.  This note is a SYMBOL_REF.  */
 213 REG_NOTE (CALL_DECL)