1 | /* Register note definitions. |
2 | Copyright (C) 2004-2023 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 | CFA related notes meant for RTX_FRAME_RELATED_P instructions |
26 | should be declared with REG_CFA_NOTE macro instead of REG_NOTE. */ |
27 | |
28 | /* Shorthand. */ |
29 | #define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME) |
30 | #ifndef REG_CFA_NOTE |
31 | # define REG_CFA_NOTE(NAME) REG_NOTE (NAME) |
32 | #endif |
33 | |
34 | /* REG_DEP_TRUE is used in scheduler dependencies lists to represent a |
35 | read-after-write dependency (i.e. a true data dependency). This is |
36 | here, not grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some |
37 | passes use a literal 0 for it. */ |
38 | REG_NOTE (DEP_TRUE) |
39 | |
40 | /* The value in REG dies in this insn (i.e., it is not needed past |
41 | this insn). If REG is set in this insn, the REG_DEAD note may, |
42 | but need not, be omitted. */ |
43 | REG_NOTE (DEAD) |
44 | |
45 | /* The REG is autoincremented or autodecremented in this insn. */ |
46 | REG_NOTE (INC) |
47 | |
48 | /* Describes the insn as a whole; it says that the insn sets a |
49 | register to a constant value or to be equivalent to a memory |
50 | address. If the register is spilled to the stack then the constant |
51 | value should be substituted for it. The contents of the REG_EQUIV |
52 | is the constant value or memory address, which may be different |
53 | from the source of the SET although it has the same value. A |
54 | REG_EQUIV note may also appear on an insn which copies a register |
55 | parameter to a pseudo-register, if there is a memory address which |
56 | could be used to hold that pseudo-register throughout the function. */ |
57 | REG_NOTE (EQUIV) |
58 | |
59 | /* Like REG_EQUIV except that the destination is only momentarily |
60 | equal to the specified rtx. Therefore, it cannot be used for |
61 | substitution; but it can be used for cse. */ |
62 | REG_NOTE (EQUAL) |
63 | |
64 | /* The register is always nonnegative during the containing loop. |
65 | This is used in branches so that decrement and branch instructions |
66 | terminating on zero can be matched. There must be an insn pattern |
67 | in the md file named `decrement_and_branch_until_zero' or else this |
68 | will never be added to any instructions. */ |
69 | REG_NOTE (NONNEG) |
70 | |
71 | /* Identifies a register set in this insn and never used. */ |
72 | REG_NOTE (UNUSED) |
73 | |
74 | /* Points to a CODE_LABEL. Used by JUMP_INSNs to say that the CODE_LABEL |
75 | contained in the REG_LABEL_TARGET note is a possible jump target of |
76 | this insn. This note is an INSN_LIST. */ |
77 | REG_NOTE (LABEL_TARGET) |
78 | |
79 | /* Points to a CODE_LABEL. Used by any insn to say that the CODE_LABEL |
80 | contained in the REG_LABEL_OPERAND note is used by the insn, but as an |
81 | operand, not as a jump target (though it may indirectly be a jump |
82 | target for a later jump insn). This note is an INSN_LIST. */ |
83 | REG_NOTE (LABEL_OPERAND) |
84 | |
85 | /* REG_DEP_OUTPUT and REG_DEP_ANTI are used in scheduler dependencies lists |
86 | to represent write-after-write and write-after-read dependencies |
87 | respectively. */ |
88 | REG_NOTE (DEP_OUTPUT) |
89 | REG_NOTE (DEP_ANTI) |
90 | REG_NOTE (DEP_CONTROL) |
91 | |
92 | /* REG_BR_PROB is attached to JUMP_INSNs. It has an |
93 | integer value (in an INT_LIST). For jumps, it is the probability |
94 | that this is a taken branch. The integer represents a value of |
95 | profile_probability type. Use to_reg_br_prob_note and from_reg_br_prob_note |
96 | to extract the actual value. */ |
97 | REG_NOTE (BR_PROB) |
98 | |
99 | /* Attached to a move insn which receives the result of a call; indicates that |
100 | the call is malloc-like and that the pointer returned cannot alias anything |
101 | else. */ |
102 | REG_NOTE (NOALIAS) |
103 | |
104 | /* REG_BR_PRED is attached to JUMP_INSNs. It contains |
105 | CONCAT of two integer value. First specifies the branch predictor |
106 | that added the note, second specifies the predicted hitrate of |
107 | branch in a fixed point arithmetic based on REG_BR_PROB_BASE. */ |
108 | REG_NOTE (BR_PRED) |
109 | |
110 | /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex |
111 | for DWARF to interpret what they imply. The attached rtx is used |
112 | instead of intuition. */ |
113 | REG_CFA_NOTE (FRAME_RELATED_EXPR) |
114 | |
115 | /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex |
116 | for FRAME_RELATED_EXPR intuition. The insn's first pattern must be |
117 | a SET, and the destination must be the CFA register. The attached |
118 | rtx is an expression that defines the CFA. In the simplest case, the |
119 | rtx could be just the stack_pointer_rtx; more common would be a PLUS |
120 | with a base register and a constant offset. In the most complicated |
121 | cases, this will result in a DW_CFA_def_cfa_expression with the rtx |
122 | expression rendered in a dwarf location expression. */ |
123 | REG_CFA_NOTE (CFA_DEF_CFA) |
124 | |
125 | /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex |
126 | for FRAME_RELATED_EXPR intuition. This note adjusts the expression |
127 | from which the CFA is computed. The attached rtx defines a new CFA |
128 | expression, relative to the old CFA expression. This rtx must be of |
129 | the form (SET new-cfa-reg (PLUS old-cfa-reg const_int)). If the note |
130 | rtx is NULL, we use the first SET of the insn. */ |
131 | REG_CFA_NOTE (CFA_ADJUST_CFA) |
132 | |
133 | /* Similar to FRAME_RELATED_EXPR, with the additional information that |
134 | this is a save to memory, i.e. will result in DW_CFA_offset or the |
135 | like. The pattern or the insn should be a simple store relative to |
136 | the CFA. */ |
137 | REG_CFA_NOTE (CFA_OFFSET) |
138 | |
139 | /* Similar to FRAME_RELATED_EXPR, with the additional information that this |
140 | is a save to a register, i.e. will result in DW_CFA_register. The insn |
141 | or the pattern should be simple reg-reg move. */ |
142 | REG_CFA_NOTE (CFA_REGISTER) |
143 | |
144 | /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex |
145 | for FRAME_RELATED_EXPR intuition. This is a save to memory, i.e. will |
146 | result in a DW_CFA_expression. The pattern or the insn should be a |
147 | store of a register to an arbitrary (non-validated) memory address. */ |
148 | REG_CFA_NOTE (CFA_EXPRESSION) |
149 | |
150 | /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex |
151 | for FRAME_RELATED_EXPR intuition. The DWARF expression computes the value of |
152 | the given register. */ |
153 | REG_CFA_NOTE (CFA_VAL_EXPRESSION) |
154 | |
155 | /* Attached to insns that are RTX_FRAME_RELATED_P, with the information |
156 | that this is a restore operation, i.e. will result in DW_CFA_restore |
157 | or the like. Either the attached rtx, or the destination of the insn's |
158 | first pattern is the register to be restored. */ |
159 | REG_CFA_NOTE (CFA_RESTORE) |
160 | |
161 | /* Like CFA_RESTORE but without actually emitting CFI. This can be |
162 | used to tell the verification infrastructure that a register is |
163 | saved without intending to restore it. */ |
164 | REG_CFA_NOTE (CFA_NO_RESTORE) |
165 | |
166 | /* Attached to insns that are RTX_FRAME_RELATED_P, marks insn that sets |
167 | vDRAP from DRAP. If vDRAP is a register, vdrap_reg is initalized |
168 | to the argument, if it is a MEM, it is ignored. */ |
169 | REG_CFA_NOTE (CFA_SET_VDRAP) |
170 | |
171 | /* Attached to insns that are RTX_FRAME_RELATED_P, indicating a window |
172 | save operation, i.e. will result in a DW_CFA_GNU_window_save. |
173 | The argument is ignored. */ |
174 | REG_CFA_NOTE (CFA_WINDOW_SAVE) |
175 | |
176 | /* Attached to insns that are RTX_FRAME_RELATED_P, marks the insn as |
177 | requiring that all queued information should be flushed *before* insn, |
178 | regardless of what is visible in the rtl. The argument is ignored. |
179 | This is normally used for a call instruction which is not exposed to |
180 | the rest of the compiler as a CALL_INSN. */ |
181 | REG_CFA_NOTE (CFA_FLUSH_QUEUE) |
182 | |
183 | /* Attached to insns that are RTX_FRAME_RELATED_P, toggling the mangling status |
184 | of return address. Currently it's only used by AArch64. The argument is |
185 | ignored. */ |
186 | REG_CFA_NOTE (CFA_TOGGLE_RA_MANGLE) |
187 | |
188 | /* Indicates what exception region an INSN belongs in. This is used |
189 | to indicate what region to which a call may throw. REGION 0 |
190 | indicates that a call cannot throw at all. REGION -1 indicates |
191 | that it cannot throw, nor will it execute a non-local goto. */ |
192 | REG_NOTE (EH_REGION) |
193 | |
194 | /* Used by haifa-sched to save NOTE_INSN notes across scheduling. */ |
195 | REG_NOTE (SAVE_NOTE) |
196 | |
197 | /* Indicates that a call does not return. */ |
198 | REG_NOTE (NORETURN) |
199 | |
200 | /* Indicates that an indirect jump is a non-local goto instead of a |
201 | computed goto. */ |
202 | REG_NOTE (NON_LOCAL_GOTO) |
203 | |
204 | /* This kind of note is generated at each to `setjmp', and similar |
205 | functions that can return twice. */ |
206 | REG_NOTE (SETJMP) |
207 | |
208 | /* This kind of note is generated at each transactional memory |
209 | builtin, to indicate we need to generate transaction restart |
210 | edges for this insn. */ |
211 | REG_NOTE (TM) |
212 | |
213 | /* Indicates the cumulative offset of the stack pointer accounting |
214 | for pushed arguments. This will only be generated when |
215 | ACCUMULATE_OUTGOING_ARGS is false. */ |
216 | REG_NOTE (ARGS_SIZE) |
217 | |
218 | /* Used for communication between IRA and caller-save.cc, indicates |
219 | that the return value of a call can be used to reinitialize a |
220 | pseudo reg. */ |
221 | REG_NOTE (RETURNED) |
222 | |
223 | /* Indicates the instruction is a stack check probe that should not |
224 | be combined with other stack adjustments. */ |
225 | REG_NOTE (STACK_CHECK) |
226 | |
227 | /* Used to mark a call with the function decl called by the call. |
228 | The decl might not be available in the call due to splitting of the call |
229 | insn. This note is a SYMBOL_REF. */ |
230 | REG_NOTE (CALL_DECL) |
231 | |
232 | /* Indicates that the call is an untyped_call. These calls are special |
233 | in that they set all of the target ABI's return value registers to a |
234 | defined value without explicitly saying so. For example, a typical |
235 | untyped_call sequence has the form: |
236 | |
237 | (call (mem (symbol_ref "foo"))) |
238 | (set (reg pseudo1) (reg result1)) |
239 | ... |
240 | (set (reg pseudon) (reg resultn)) |
241 | |
242 | The ABI specifies that result1..resultn are clobbered by the call, |
243 | but the RTL does not indicate that result1..resultn are the results |
244 | of the call. */ |
245 | REG_NOTE (UNTYPED_CALL) |
246 | |
247 | /* Indicate that a call should not be verified for control-flow consistency. |
248 | The target address of the call is assumed as a valid address and no check |
249 | to validate a branch to the target address is needed. The call is marked |
250 | when a called function has a 'notrack' attribute. This note is used by the |
251 | compiler when the option -fcf-protection=branch is specified. */ |
252 | REG_NOTE (CALL_NOCF_CHECK) |
253 | |
254 | /* The values passed to callee, for debuginfo purposes. */ |
255 | REG_NOTE (CALL_ARG_LOCATION) |
256 | |