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cfc14b3a MK |
1 | /* Frame unwinder for frames with DWARF Call Frame Information. |
2 | ||
42a4f53d | 3 | Copyright (C) 2003-2019 Free Software Foundation, Inc. |
cfc14b3a MK |
4 | |
5 | Contributed by Mark Kettenis. | |
6 | ||
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 11 | the Free Software Foundation; either version 3 of the License, or |
cfc14b3a MK |
12 | (at your option) any later version. |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
cfc14b3a MK |
21 | |
22 | #ifndef DWARF2_FRAME_H | |
23 | #define DWARF2_FRAME_H 1 | |
24 | ||
ecc9ac84 | 25 | struct gdbarch; |
cfc14b3a | 26 | struct objfile; |
e6e5e94c | 27 | struct frame_info; |
9f6f94ff TT |
28 | struct dwarf2_per_cu_data; |
29 | struct agent_expr; | |
30 | struct axs_value; | |
cfc14b3a | 31 | |
05cbe71a MK |
32 | /* Register rule. */ |
33 | ||
34 | enum dwarf2_frame_reg_rule | |
35 | { | |
36 | /* Make certain that 0 maps onto the correct enum value; the | |
37 | corresponding structure is being initialized using memset zero. | |
38 | This indicates that CFI didn't provide any information at all | |
39 | about a register, leaving how to obtain its value totally | |
40 | unspecified. */ | |
41 | DWARF2_FRAME_REG_UNSPECIFIED = 0, | |
42 | ||
43 | /* The term "undefined" comes from the DWARF2 CFI spec which this | |
44 | code is moddeling; it indicates that the register's value is | |
45 | "undefined". GCC uses the less formal term "unsaved". Its | |
46 | definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED. | |
47 | The failure to differentiate the two helps explain a few problems | |
48 | with the CFI generated by GCC. */ | |
49 | DWARF2_FRAME_REG_UNDEFINED, | |
50 | DWARF2_FRAME_REG_SAVED_OFFSET, | |
51 | DWARF2_FRAME_REG_SAVED_REG, | |
52 | DWARF2_FRAME_REG_SAVED_EXP, | |
53 | DWARF2_FRAME_REG_SAME_VALUE, | |
54 | ||
46ea248b AO |
55 | /* These are defined in Dwarf3. */ |
56 | DWARF2_FRAME_REG_SAVED_VAL_OFFSET, | |
57 | DWARF2_FRAME_REG_SAVED_VAL_EXP, | |
58 | ||
05cbe71a MK |
59 | /* These aren't defined by the DWARF2 CFI specification, but are |
60 | used internally by GDB. */ | |
b39cc962 | 61 | DWARF2_FRAME_REG_FN, /* Call a registered function. */ |
05cbe71a | 62 | DWARF2_FRAME_REG_RA, /* Return Address. */ |
8d5a9abc | 63 | DWARF2_FRAME_REG_RA_OFFSET, /* Return Address with offset. */ |
ea7963f0 FR |
64 | DWARF2_FRAME_REG_CFA, /* Call Frame Address. */ |
65 | DWARF2_FRAME_REG_CFA_OFFSET /* Call Frame Address with offset. */ | |
05cbe71a MK |
66 | }; |
67 | ||
68 | /* Register state. */ | |
69 | ||
70 | struct dwarf2_frame_state_reg | |
71 | { | |
72 | /* Each register save state can be described in terms of a CFA slot, | |
73 | another register, or a location expression. */ | |
74 | union { | |
75 | LONGEST offset; | |
76 | ULONGEST reg; | |
b348037f YQ |
77 | struct |
78 | { | |
79 | const gdb_byte *start; | |
80 | ULONGEST len; | |
81 | } exp; | |
b39cc962 DJ |
82 | struct value *(*fn) (struct frame_info *this_frame, void **this_cache, |
83 | int regnum); | |
05cbe71a | 84 | } loc; |
05cbe71a MK |
85 | enum dwarf2_frame_reg_rule how; |
86 | }; | |
87 | ||
b41c5a85 JW |
88 | enum cfa_how_kind |
89 | { | |
90 | CFA_UNSET, | |
91 | CFA_REG_OFFSET, | |
92 | CFA_EXP | |
93 | }; | |
94 | ||
95 | struct dwarf2_frame_state_reg_info | |
96 | { | |
1c90d9f0 YQ |
97 | dwarf2_frame_state_reg_info () = default; |
98 | ~dwarf2_frame_state_reg_info () | |
99 | { | |
100 | delete prev; | |
1c90d9f0 YQ |
101 | } |
102 | ||
103 | /* Copy constructor. */ | |
104 | dwarf2_frame_state_reg_info (const dwarf2_frame_state_reg_info &src) | |
780942fc | 105 | : reg (src.reg), cfa_offset (src.cfa_offset), |
1c90d9f0 YQ |
106 | cfa_reg (src.cfa_reg), cfa_how (src.cfa_how), cfa_exp (src.cfa_exp), |
107 | prev (src.prev) | |
108 | { | |
1c90d9f0 YQ |
109 | } |
110 | ||
111 | /* Assignment operator for both move-assignment and copy-assignment. */ | |
112 | dwarf2_frame_state_reg_info& | |
113 | operator= (dwarf2_frame_state_reg_info rhs) | |
114 | { | |
115 | swap (*this, rhs); | |
116 | return *this; | |
117 | } | |
118 | ||
119 | /* Move constructor. */ | |
120 | dwarf2_frame_state_reg_info (dwarf2_frame_state_reg_info &&rhs) noexcept | |
780942fc | 121 | : reg (std::move (rhs.reg)), cfa_offset (rhs.cfa_offset), |
1c90d9f0 YQ |
122 | cfa_reg (rhs.cfa_reg), cfa_how (rhs.cfa_how), cfa_exp (rhs.cfa_exp), |
123 | prev (rhs.prev) | |
124 | { | |
125 | rhs.prev = nullptr; | |
1c90d9f0 | 126 | } |
b41c5a85 | 127 | |
780942fc TT |
128 | /* If necessary, enlarge the register set to hold NUM_REGS_REQUESTED |
129 | registers. */ | |
1c90d9f0 YQ |
130 | void alloc_regs (int num_regs_requested) |
131 | { | |
780942fc | 132 | gdb_assert (num_regs_requested > 0); |
1c90d9f0 | 133 | |
780942fc TT |
134 | if (num_regs_requested <= reg.size ()) |
135 | return; | |
1c90d9f0 | 136 | |
780942fc | 137 | reg.resize (num_regs_requested); |
1c90d9f0 YQ |
138 | } |
139 | ||
780942fc | 140 | std::vector<struct dwarf2_frame_state_reg> reg; |
1c90d9f0 YQ |
141 | |
142 | LONGEST cfa_offset = 0; | |
143 | ULONGEST cfa_reg = 0; | |
144 | enum cfa_how_kind cfa_how = CFA_UNSET; | |
145 | const gdb_byte *cfa_exp = NULL; | |
b41c5a85 JW |
146 | |
147 | /* Used to implement DW_CFA_remember_state. */ | |
1c90d9f0 YQ |
148 | struct dwarf2_frame_state_reg_info *prev = NULL; |
149 | ||
150 | private: | |
151 | friend void swap (dwarf2_frame_state_reg_info& lhs, | |
152 | dwarf2_frame_state_reg_info& rhs) | |
153 | { | |
154 | using std::swap; | |
155 | ||
156 | swap (lhs.reg, rhs.reg); | |
1c90d9f0 YQ |
157 | swap (lhs.cfa_offset, rhs.cfa_offset); |
158 | swap (lhs.cfa_reg, rhs.cfa_reg); | |
159 | swap (lhs.cfa_how, rhs.cfa_how); | |
160 | swap (lhs.cfa_exp, rhs.cfa_exp); | |
161 | swap (lhs.prev, rhs.prev); | |
162 | } | |
b41c5a85 JW |
163 | }; |
164 | ||
afe37d6b YQ |
165 | struct dwarf2_cie; |
166 | ||
b41c5a85 JW |
167 | /* Structure describing a frame state. */ |
168 | ||
169 | struct dwarf2_frame_state | |
170 | { | |
afe37d6b | 171 | dwarf2_frame_state (CORE_ADDR pc, struct dwarf2_cie *cie); |
afe37d6b | 172 | |
b41c5a85 JW |
173 | /* Each register save state can be described in terms of a CFA slot, |
174 | another register, or a location expression. */ | |
afe37d6b | 175 | struct dwarf2_frame_state_reg_info regs {}; |
b41c5a85 JW |
176 | |
177 | /* The PC described by the current frame state. */ | |
178 | CORE_ADDR pc; | |
179 | ||
180 | /* Initial register set from the CIE. | |
181 | Used to implement DW_CFA_restore. */ | |
afe37d6b | 182 | struct dwarf2_frame_state_reg_info initial {}; |
b41c5a85 JW |
183 | |
184 | /* The information we care about from the CIE. */ | |
afe37d6b YQ |
185 | const LONGEST data_align; |
186 | const ULONGEST code_align; | |
187 | const ULONGEST retaddr_column; | |
b41c5a85 JW |
188 | |
189 | /* Flags for known producer quirks. */ | |
190 | ||
191 | /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa | |
192 | and DW_CFA_def_cfa_offset takes a factored offset. */ | |
afe37d6b | 193 | bool armcc_cfa_offsets_sf = false; |
b41c5a85 JW |
194 | |
195 | /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that | |
196 | the CFA is defined as REG - OFFSET rather than REG + OFFSET. */ | |
afe37d6b | 197 | bool armcc_cfa_offsets_reversed = false; |
b41c5a85 JW |
198 | }; |
199 | ||
3c3bb058 AB |
200 | /* When this is true the DWARF frame unwinders can be used if they are |
201 | registered with the gdbarch. Not all architectures can or do use the | |
202 | DWARF unwinders. Setting this to true on a target that does not | |
203 | otherwise support the DWARF unwinders has no effect. */ | |
491144b5 | 204 | extern bool dwarf2_frame_unwinders_enabled_p; |
3c3bb058 | 205 | |
8f22cb90 MK |
206 | /* Set the architecture-specific register state initialization |
207 | function for GDBARCH to INIT_REG. */ | |
208 | ||
209 | extern void dwarf2_frame_set_init_reg (struct gdbarch *gdbarch, | |
210 | void (*init_reg) (struct gdbarch *, int, | |
aff37fc1 DM |
211 | struct dwarf2_frame_state_reg *, |
212 | struct frame_info *)); | |
8f22cb90 | 213 | |
3ed09a32 DJ |
214 | /* Set the architecture-specific signal trampoline recognition |
215 | function for GDBARCH to SIGNAL_FRAME_P. */ | |
216 | ||
217 | extern void | |
218 | dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch, | |
219 | int (*signal_frame_p) (struct gdbarch *, | |
220 | struct frame_info *)); | |
221 | ||
4fc771b8 DJ |
222 | /* Set the architecture-specific adjustment of .eh_frame and .debug_frame |
223 | register numbers. */ | |
4bf8967c AS |
224 | |
225 | extern void | |
4fc771b8 DJ |
226 | dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch, |
227 | int (*adjust_regnum) (struct gdbarch *, | |
228 | int, int)); | |
4bf8967c | 229 | |
4a4e5149 | 230 | /* Append the DWARF-2 frame unwinders to GDBARCH's list. */ |
cfc14b3a | 231 | |
4a4e5149 | 232 | void dwarf2_append_unwinders (struct gdbarch *gdbarch); |
cfc14b3a MK |
233 | |
234 | /* Return the frame base methods for the function that contains PC, or | |
235 | NULL if it can't be handled by the DWARF CFI frame unwinder. */ | |
236 | ||
05cbe71a | 237 | extern const struct frame_base * |
4a4e5149 | 238 | dwarf2_frame_base_sniffer (struct frame_info *this_frame); |
cfc14b3a | 239 | |
e7802207 TT |
240 | /* Compute the DWARF CFA for a frame. */ |
241 | ||
242 | CORE_ADDR dwarf2_frame_cfa (struct frame_info *this_frame); | |
243 | ||
a8fd5589 TT |
244 | /* Find the CFA information for PC. |
245 | ||
246 | Return 1 if a register is used for the CFA, or 0 if another | |
247 | expression is used. Throw an exception on error. | |
248 | ||
249 | GDBARCH is the architecture to use. | |
250 | DATA is the per-CU data. | |
251 | ||
252 | REGNUM_OUT is an out parameter that is set to the register number. | |
253 | OFFSET_OUT is the offset to use from this register. | |
254 | These are only filled in when 1 is returned. | |
255 | ||
256 | TEXT_OFFSET_OUT, CFA_START_OUT, and CFA_END_OUT describe the CFA | |
257 | in other cases. These are only used when 0 is returned. */ | |
258 | ||
259 | extern int dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc, | |
260 | struct dwarf2_per_cu_data *data, | |
261 | int *regnum_out, LONGEST *offset_out, | |
262 | CORE_ADDR *text_offset_out, | |
263 | const gdb_byte **cfa_start_out, | |
264 | const gdb_byte **cfa_end_out); | |
9f6f94ff | 265 | |
cfc14b3a | 266 | #endif /* dwarf2-frame.h */ |