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/* Register note definitions.
Copyright (C) 2004-2024 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
/* This file defines all the codes that may appear on individual
EXPR_LIST, INSN_LIST and INT_LIST rtxes in the REG_NOTES chain of an insn.
The codes are stored in the mode field of the rtx. Source files
define DEF_REG_NOTE appropriately before including this file.
CFA related notes meant for RTX_FRAME_RELATED_P instructions
should be declared with REG_CFA_NOTE macro instead of REG_NOTE. */
/* Shorthand. */
#define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME)
#ifndef REG_CFA_NOTE
# define REG_CFA_NOTE(NAME) REG_NOTE (NAME)
#endif
/* REG_DEP_TRUE is used in scheduler dependencies lists to represent a
read-after-write dependency (i.e. a true data dependency). This is
here, not grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some
passes use a literal 0 for it. */
REG_NOTE (DEP_TRUE)
/* The value in REG dies in this insn (i.e., it is not needed past
this insn). If REG is set in this insn, the REG_DEAD note may,
but need not, be omitted. */
REG_NOTE (DEAD)
/* The REG is autoincremented or autodecremented in this insn. */
REG_NOTE (INC)
/* Describes the insn as a whole; it says that the insn sets a
register to a constant value or to be equivalent to a memory
address. If the register is spilled to the stack then the constant
value should be substituted for it. The contents of the REG_EQUIV
is the constant value or memory address, which may be different
from the source of the SET although it has the same value. A
REG_EQUIV note may also appear on an insn which copies a register
parameter to a pseudo-register, if there is a memory address which
could be used to hold that pseudo-register throughout the function. */
REG_NOTE (EQUIV)
/* Like REG_EQUIV except that the destination is only momentarily
equal to the specified rtx. Therefore, it cannot be used for
substitution; but it can be used for cse. */
REG_NOTE (EQUAL)
/* The register is always nonnegative during the containing loop.
This is used in branches so that decrement and branch instructions
terminating on zero can be matched. There must be an insn pattern
in the md file named `decrement_and_branch_until_zero' or else this
will never be added to any instructions. */
REG_NOTE (NONNEG)
/* Identifies a register set in this insn and never used. */
REG_NOTE (UNUSED)
/* Points to a CODE_LABEL. Used by JUMP_INSNs to say that the CODE_LABEL
contained in the REG_LABEL_TARGET note is a possible jump target of
this insn. This note is an INSN_LIST. */
REG_NOTE (LABEL_TARGET)
/* Points to a CODE_LABEL. Used by any insn to say that the CODE_LABEL
contained in the REG_LABEL_OPERAND note is used by the insn, but as an
operand, not as a jump target (though it may indirectly be a jump
target for a later jump insn). This note is an INSN_LIST. */
REG_NOTE (LABEL_OPERAND)
/* REG_DEP_OUTPUT and REG_DEP_ANTI are used in scheduler dependencies lists
to represent write-after-write and write-after-read dependencies
respectively. */
REG_NOTE (DEP_OUTPUT)
REG_NOTE (DEP_ANTI)
REG_NOTE (DEP_CONTROL)
/* REG_BR_PROB is attached to JUMP_INSNs. It has an
integer value (in an INT_LIST). For jumps, it is the probability
that this is a taken branch. The integer represents a value of
profile_probability type. Use to_reg_br_prob_note and from_reg_br_prob_note
to extract the actual value. */
REG_NOTE (BR_PROB)
/* Attached to a move insn which receives the result of a call; indicates that
the call is malloc-like and that the pointer returned cannot alias anything
else. */
REG_NOTE (NOALIAS)
/* REG_BR_PRED is attached to JUMP_INSNs. It contains
CONCAT of two integer value. First specifies the branch predictor
that added the note, second specifies the predicted hitrate of
branch in a fixed point arithmetic based on REG_BR_PROB_BASE. */
REG_NOTE (BR_PRED)
/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
for DWARF to interpret what they imply. The attached rtx is used
instead of intuition. */
REG_CFA_NOTE (FRAME_RELATED_EXPR)
/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
for FRAME_RELATED_EXPR intuition. The insn's first pattern must be
a SET, and the destination must be the CFA register. The attached
rtx is an expression that defines the CFA. In the simplest case, the
rtx could be just the stack_pointer_rtx; more common would be a PLUS
with a base register and a constant offset. In the most complicated
cases, this will result in a DW_CFA_def_cfa_expression with the rtx
expression rendered in a dwarf location expression. */
REG_CFA_NOTE (CFA_DEF_CFA)
/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
for FRAME_RELATED_EXPR intuition. This note adjusts the expression
from which the CFA is computed. The attached rtx defines a new CFA
expression, relative to the old CFA expression. This rtx must be of
the form (SET new-cfa-reg (PLUS old-cfa-reg const_int)). If the note
rtx is NULL, we use the first SET of the insn. */
REG_CFA_NOTE (CFA_ADJUST_CFA)
/* Similar to FRAME_RELATED_EXPR, with the additional information that
this is a save to memory, i.e. will result in DW_CFA_offset or the
like. The pattern or the insn should be a simple store relative to
the CFA. */
REG_CFA_NOTE (CFA_OFFSET)
/* Similar to FRAME_RELATED_EXPR, with the additional information that this
is a save to a register, i.e. will result in DW_CFA_register. The insn
or the pattern should be simple reg-reg move. */
REG_CFA_NOTE (CFA_REGISTER)
/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
for FRAME_RELATED_EXPR intuition. This is a save to memory, i.e. will
result in a DW_CFA_expression. The pattern or the insn should be a
store of a register to an arbitrary (non-validated) memory address. */
REG_CFA_NOTE (CFA_EXPRESSION)
/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
for FRAME_RELATED_EXPR intuition. The DWARF expression computes the value of
the given register. */
REG_CFA_NOTE (CFA_VAL_EXPRESSION)
/* Attached to insns that are RTX_FRAME_RELATED_P, with the information
that this is a restore operation, i.e. will result in DW_CFA_restore
or the like. Either the attached rtx, or the destination of the insn's
first pattern is the register to be restored. */
REG_CFA_NOTE (CFA_RESTORE)
/* Like CFA_RESTORE but without actually emitting CFI. This can be
used to tell the verification infrastructure that a register is
saved without intending to restore it. */
REG_CFA_NOTE (CFA_NO_RESTORE)
/* Attached to insns that are RTX_FRAME_RELATED_P, marks insn that sets
vDRAP from DRAP. If vDRAP is a register, vdrap_reg is initalized
to the argument, if it is a MEM, it is ignored. */
REG_CFA_NOTE (CFA_SET_VDRAP)
/* Attached to insns that are RTX_FRAME_RELATED_P, indicating a window
save operation, i.e. will result in a DW_CFA_GNU_window_save.
The argument is ignored. */
REG_CFA_NOTE (CFA_WINDOW_SAVE)
/* Attached to insns that are RTX_FRAME_RELATED_P, marks the insn as
requiring that all queued information should be flushed *before* insn,
regardless of what is visible in the rtl. The argument is ignored.
This is normally used for a call instruction which is not exposed to
the rest of the compiler as a CALL_INSN. */
REG_CFA_NOTE (CFA_FLUSH_QUEUE)
/* Attached to insns that are RTX_FRAME_RELATED_P, toggling the mangling status
of return address. Currently it's only used by AArch64. The argument is
ignored. */
REG_CFA_NOTE (CFA_TOGGLE_RA_MANGLE)
/* Indicates what exception region an INSN belongs in. This is used
to indicate what region to which a call may throw. REGION 0
indicates that a call cannot throw at all. REGION -1 indicates
that it cannot throw, nor will it execute a non-local goto. */
REG_NOTE (EH_REGION)
/* Used by haifa-sched to save NOTE_INSN notes across scheduling. */
REG_NOTE (SAVE_NOTE)
/* Indicates that a call does not return. */
REG_NOTE (NORETURN)
/* Indicates that an indirect jump is a non-local goto instead of a
computed goto. */
REG_NOTE (NON_LOCAL_GOTO)
/* This kind of note is generated at each to `setjmp', and similar
functions that can return twice. */
REG_NOTE (SETJMP)
/* This kind of note is generated at each transactional memory
builtin, to indicate we need to generate transaction restart
edges for this insn. */
REG_NOTE (TM)
/* Indicates the cumulative offset of the stack pointer accounting
for pushed arguments. This will only be generated when
ACCUMULATE_OUTGOING_ARGS is false. */
REG_NOTE (ARGS_SIZE)
/* Used for communication between IRA and caller-save.cc, indicates
that the return value of a call can be used to reinitialize a
pseudo reg. */
REG_NOTE (RETURNED)
/* Indicates the instruction is a stack check probe that should not
be combined with other stack adjustments. */
REG_NOTE (STACK_CHECK)
/* Used to mark a call with the function decl called by the call.
The decl might not be available in the call due to splitting of the call
insn. This note is a SYMBOL_REF. */
REG_NOTE (CALL_DECL)
/* Indicates that the call is an untyped_call. These calls are special
in that they set all of the target ABI's return value registers to a
defined value without explicitly saying so. For example, a typical
untyped_call sequence has the form:
(call (mem (symbol_ref "foo")))
(set (reg pseudo1) (reg result1))
...
(set (reg pseudon) (reg resultn))
The ABI specifies that result1..resultn are clobbered by the call,
but the RTL does not indicate that result1..resultn are the results
of the call. */
REG_NOTE (UNTYPED_CALL)
/* Indicate that a call should not be verified for control-flow consistency.
The target address of the call is assumed as a valid address and no check
to validate a branch to the target address is needed. The call is marked
when a called function has a 'notrack' attribute. This note is used by the
compiler when the option -fcf-protection=branch is specified. */
REG_NOTE (CALL_NOCF_CHECK)
/* The values passed to callee, for debuginfo purposes. */
REG_NOTE (CALL_ARG_LOCATION)
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