gcc/reg-notes.def

   1 /* Register note definitions.
   2    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along 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.  */
  33 REG_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.  */
  38 REG_NOTE (DEAD)
  39
  40 /* The REG is autoincremented or autodecremented in this insn.  */
  41 REG_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.  */
  52 REG_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.  */
  57 REG_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.  */
  64 REG_NOTE (NONNEG)
  65
  66 /* Identifies a register set in this insn and never used.  */
  67 REG_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.  */
  76 REG_NOTE (CC_SETTER)
  77 REG_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.  */
  82 REG_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.  */
  88 REG_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.  */
  93 REG_NOTE (DEP_OUTPUT)
  94 REG_NOTE (DEP_ANTI)
  95 REG_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.  */
 101 REG_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.  */
 105 REG_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.  */
 111 REG_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.  */
 116 REG_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.  */
 126 REG_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.  */
 134 REG_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.  */
 140 REG_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.  */
 145 REG_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.  */
 151 REG_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.  */
 157 REG_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.  */
 162 REG_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.  */
 167 REG_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.  */
 174 REG_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.  */
 179 REG_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.  */
 185 REG_NOTE (EH_REGION)
 186
 187 /* Used by haifa-sched to save NOTE_INSN notes across scheduling.  */
 188 REG_NOTE (SAVE_NOTE)
 189
 190 /* Indicates that a call does not return.  */
 191 REG_NOTE (NORETURN)
 192
 193 /* Indicates that an indirect jump is a non-local goto instead of a
 194    computed goto.  */
 195 REG_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.  */
 200 REG_NOTE (CROSSING_JUMP)
 201
 202 /* This kind of note is generated at each to `setjmp', and similar
 203    functions that can return twice.  */
 204 REG_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.  */
 209 REG_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.  */
 214 REG_NOTE (ARGS_SIZE)
 215
 216 /* Used for communication between IRA and caller-save.c, indicates
 217    that the return value of a call can be used to reinitialize a
 218    pseudo reg.  */
 219 REG_NOTE (RETURNED)