1/* gen-sframe.h - Support for generating SFrame.
2   Copyright (C) 2022-2024 Free Software Foundation, Inc.
3
4   This file is part of GAS, the GNU Assembler.
5
6   GAS is free software; you can redistribute it and/or modify
7   it under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 3, or (at your option)
9   any later version.
10
11   GAS is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14   GNU General Public License for more details.
15
16   You should have received a copy of the GNU General Public License
17   along with GAS; see the file COPYING.  If not, write to the Free
18   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
19   02110-1301, USA.  */
20
21#ifndef GENSFRAME_H
22#define GENSFRAME_H
23
24#define SFRAME_FRE_ELEM_LOC_REG		0
25#define SFRAME_FRE_ELEM_LOC_STACK	1
26
27/* SFrame Frame Row Entry (FRE).
28
29   A frame row entry is a slice of the frame and can be valid for a set of
30   program instructions.  It keeps all information needed to retrieve the CFA
31   and the Return Address (RA) if tracked.
32
33   A frame row entry effectively stores accumulated information gathered by
34   interpreting multiple CFI instructions.  More precisely, it is a
35   self-sufficient record in its own right.  Only the subset of information
36   necessary for unwinding is stored: Given a PC, how to retrieve the CFA and
37   the RA.
38*/
39
40struct sframe_row_entry
41{
42  /* A linked list.  */
43  struct sframe_row_entry *next;
44
45  /* Start and end of the frame row entry.  */
46  symbolS *pc_begin;
47  symbolS *pc_end;
48
49  /* A frame row entry is a merge candidate if new information can be updated
50     on it.  */
51  bool merge_candidate;
52
53  /* Whether the return address is mangled with pauth code.  */
54  bool mangled_ra_p;
55
56  /* Track CFA base (architectural) register ID.  */
57  unsigned int cfa_base_reg;
58  /* Offset from the CFA base register for recovering CFA.  */
59  offsetT cfa_offset;
60
61  /* Track the other register used as base register for CFA.  Specify whether
62     it is in register or memory.  */
63  unsigned int base_reg;
64  unsigned int bp_loc;
65  /* If the other register is stashed on stack, note the offset.  */
66  offsetT bp_offset;
67
68  /* Track RA location.  Specify whether it is in register or memory.  */
69  unsigned int ra_loc;
70  /* If RA is stashed on stack, note the offset.  */
71  offsetT ra_offset;
72};
73
74/* SFrame Function Description Entry.  */
75
76struct sframe_func_entry
77{
78  /* A linked list.  */
79  struct sframe_func_entry *next;
80
81  /* Reference to the FDE created from CFI in dw2gencfi.  Some information
82     like the start_address and the segment is made available via this
83     member.  */
84  const struct fde_entry *dw_fde;
85
86  /* Reference to the first FRE for this function.  */
87  struct sframe_row_entry *sframe_fres;
88
89  unsigned int num_fres;
90};
91
92/* SFrame Function Description Entry Translation Context.  */
93
94struct sframe_xlate_ctx
95{
96  /* Reference to the FDE created from CFI in dw2gencfi.  Information
97     like the FDE start_address, end_address and the cfi insns are
98     made available via this member.  */
99  const struct fde_entry *dw_fde;
100
101  /* List of FREs in the current FDE translation context, bounded by first_fre
102     and last_fre.  */
103
104  /* Keep track of the first FRE for the purpose of restoring state if
105     necessary (for DW_CFA_restore).  */
106  struct sframe_row_entry *first_fre;
107  /* The last FRE in the list.  */
108  struct sframe_row_entry *last_fre;
109
110  /* The current FRE under construction.  */
111  struct sframe_row_entry *cur_fre;
112  /* Remember FRE for an eventual restore.  */
113  struct sframe_row_entry *remember_fre;
114
115  unsigned num_xlate_fres;
116};
117
118/* Error codes for SFrame translation context.  */
119enum sframe_xlate_err
120{
121  /* Success.  */
122  SFRAME_XLATE_OK = 0,
123  /* Error.  */
124  SFRAME_XLATE_ERROR = 1,
125  /* Detailed error codes.  */
126  SFRAME_XLATE_ERR_INVAL = -1,
127  SFRAME_XLATE_ERR_NOTREPRESENTED = -2,
128};
129
130/* Callback to create the abi/arch identifier for SFrame section.  */
131
132unsigned char
133sframe_get_abi_arch_callback (const char *target_arch,
134			      int big_endian_p);
135
136/* The list of all FDEs with data in SFrame internal representation.  */
137
138extern struct sframe_func_entry *all_sframe_fdes;
139
140/* SFrame version specific operations structure.  */
141
142struct sframe_version_ops
143{
144  unsigned char format_version;    /* SFrame format version.  */
145  /* set SFrame FRE info.  */
146  unsigned char (*set_fre_info) (unsigned int, unsigned int, unsigned int,
147				 bool);
148  /* set SFrame Func info.  */
149  unsigned char (*set_func_info) (unsigned int, unsigned int, unsigned int);
150};
151
152/* Generate SFrame stack trace info and prepare contents for the output.
153   outout_sframe ()  is called at the end of file.  */
154
155extern void output_sframe (segT sframe_seg);
156
157#endif /* GENSFRAME_H */
158