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852483bc MK |
1 | /* DWARF 2 Expression Evaluator. |
2 | ||
b811d2c2 | 3 | Copyright (C) 2001-2020 Free Software Foundation, Inc. |
852483bc MK |
4 | |
5 | Contributed by Daniel Berlin <dan@dberlin.org>. | |
6 | ||
4c2df51b DJ |
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 |
4c2df51b DJ |
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/>. */ |
4c2df51b DJ |
21 | |
22 | #if !defined (DWARF2EXPR_H) | |
23 | #define DWARF2EXPR_H | |
24 | ||
d55e5aa6 | 25 | #include "leb128.h" |
4de283e4 | 26 | #include "gdbtypes.h" |
f664829e | 27 | |
89b07335 SM |
28 | struct dwarf2_per_objfile; |
29 | ||
cec03d70 TT |
30 | /* The location of a value. */ |
31 | enum dwarf_value_location | |
32 | { | |
44353522 DE |
33 | /* The piece is in memory. |
34 | The value on the dwarf stack is its address. */ | |
cec03d70 | 35 | DWARF_VALUE_MEMORY, |
44353522 DE |
36 | |
37 | /* The piece is in a register. | |
38 | The value on the dwarf stack is the register number. */ | |
cec03d70 | 39 | DWARF_VALUE_REGISTER, |
44353522 DE |
40 | |
41 | /* The piece is on the dwarf stack. */ | |
cec03d70 | 42 | DWARF_VALUE_STACK, |
44353522 | 43 | |
cec03d70 | 44 | /* The piece is a literal. */ |
cb826367 TT |
45 | DWARF_VALUE_LITERAL, |
46 | ||
47 | /* The piece was optimized out. */ | |
8cf6f0b1 TT |
48 | DWARF_VALUE_OPTIMIZED_OUT, |
49 | ||
50 | /* The piece is an implicit pointer. */ | |
51 | DWARF_VALUE_IMPLICIT_POINTER | |
cec03d70 TT |
52 | }; |
53 | ||
1e467161 SM |
54 | /* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */ |
55 | struct dwarf_expr_piece | |
56 | { | |
57 | enum dwarf_value_location location; | |
58 | ||
59 | union | |
60 | { | |
61 | struct | |
62 | { | |
63 | /* This piece's address, for DWARF_VALUE_MEMORY pieces. */ | |
64 | CORE_ADDR addr; | |
65 | /* Non-zero if the piece is known to be in memory and on | |
66 | the program's stack. */ | |
69009882 | 67 | bool in_stack_memory; |
1e467161 SM |
68 | } mem; |
69 | ||
70 | /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */ | |
71 | int regno; | |
72 | ||
73 | /* The piece's literal value, for DWARF_VALUE_STACK pieces. */ | |
74 | struct value *value; | |
75 | ||
76 | struct | |
77 | { | |
78 | /* A pointer to the data making up this piece, | |
79 | for DWARF_VALUE_LITERAL pieces. */ | |
80 | const gdb_byte *data; | |
81 | /* The length of the available data. */ | |
82 | ULONGEST length; | |
83 | } literal; | |
84 | ||
85 | /* Used for DWARF_VALUE_IMPLICIT_POINTER. */ | |
86 | struct | |
87 | { | |
88 | /* The referent DIE from DW_OP_implicit_pointer. */ | |
89 | sect_offset die_sect_off; | |
90 | /* The byte offset into the resulting data. */ | |
91 | LONGEST offset; | |
92 | } ptr; | |
93 | } v; | |
94 | ||
95 | /* The length of the piece, in bits. */ | |
96 | ULONGEST size; | |
97 | /* The piece offset, in bits. */ | |
98 | ULONGEST offset; | |
99 | }; | |
100 | ||
44353522 DE |
101 | /* The dwarf expression stack. */ |
102 | ||
103 | struct dwarf_stack_value | |
104 | { | |
d185219d SM |
105 | dwarf_stack_value (struct value *value_, int in_stack_memory_) |
106 | : value (value_), in_stack_memory (in_stack_memory_) | |
107 | {} | |
108 | ||
8a9b8146 | 109 | struct value *value; |
44353522 | 110 | |
69009882 SM |
111 | /* True if the piece is in memory and is known to be on the program's stack. |
112 | It is always ok to set this to zero. This is used, for example, to | |
113 | optimize memory access from the target. It can vastly speed up backtraces | |
114 | on long latency connections when "set stack-cache on". */ | |
115 | bool in_stack_memory; | |
44353522 DE |
116 | }; |
117 | ||
4c2df51b DJ |
118 | /* The expression evaluator works with a dwarf_expr_context, describing |
119 | its current state and its callbacks. */ | |
120 | struct dwarf_expr_context | |
121 | { | |
89b07335 | 122 | dwarf_expr_context (dwarf2_per_objfile *per_objfile); |
d185219d | 123 | virtual ~dwarf_expr_context () = default; |
718b9626 | 124 | |
69009882 | 125 | void push_address (CORE_ADDR value, bool in_stack_memory); |
595d2e30 TT |
126 | void eval (const gdb_byte *addr, size_t len); |
127 | struct value *fetch (int n); | |
128 | CORE_ADDR fetch_address (int n); | |
69009882 | 129 | bool fetch_in_stack_memory (int n); |
595d2e30 | 130 | |
d185219d SM |
131 | /* The stack of values. */ |
132 | std::vector<dwarf_stack_value> stack; | |
4c2df51b | 133 | |
f7fd4728 UW |
134 | /* Target architecture to use for address operations. */ |
135 | struct gdbarch *gdbarch; | |
136 | ||
ae0d2f24 UW |
137 | /* Target address size in bytes. */ |
138 | int addr_size; | |
139 | ||
181cebd4 JK |
140 | /* DW_FORM_ref_addr size in bytes. If -1 DWARF is executed from a frame |
141 | context and operations depending on DW_FORM_ref_addr are not allowed. */ | |
142 | int ref_addr_size; | |
143 | ||
4c2df51b DJ |
144 | /* The current depth of dwarf expression recursion, via DW_OP_call*, |
145 | DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum | |
146 | depth we'll tolerate before raising an error. */ | |
147 | int recursion_depth, max_recursion_depth; | |
148 | ||
cec03d70 TT |
149 | /* Location of the value. */ |
150 | enum dwarf_value_location location; | |
151 | ||
766062f6 | 152 | /* For DWARF_VALUE_LITERAL, the current literal value's length and |
8cf6f0b1 | 153 | data. For DWARF_VALUE_IMPLICIT_POINTER, LEN is the offset of the |
8b9737bf | 154 | target DIE of sect_offset kind. */ |
cec03d70 | 155 | ULONGEST len; |
0d45f56e | 156 | const gdb_byte *data; |
87808bd6 | 157 | |
42be36b3 CT |
158 | /* Initialization status of variable: Non-zero if variable has been |
159 | initialized; zero otherwise. */ | |
160 | int initialized; | |
161 | ||
1e467161 | 162 | /* A vector of pieces. |
87808bd6 JB |
163 | |
164 | Each time DW_OP_piece is executed, we add a new element to the | |
165 | end of this array, recording the current top of the stack, the | |
cec03d70 | 166 | current location, and the size given as the operand to |
44353522 | 167 | DW_OP_piece. We then pop the top value from the stack, reset the |
cec03d70 | 168 | location, and resume evaluation. |
87808bd6 JB |
169 | |
170 | The Dwarf spec doesn't say whether DW_OP_piece pops the top value | |
171 | from the stack. We do, ensuring that clients of this interface | |
172 | expecting to see a value left on the top of the stack (say, code | |
173 | evaluating frame base expressions or CFA's specified with | |
174 | DW_CFA_def_cfa_expression) will get an error if the expression | |
175 | actually marks all the values it computes as pieces. | |
176 | ||
177 | If an expression never uses DW_OP_piece, num_pieces will be zero. | |
178 | (It would be nice to present these cases as expressions yielding | |
cec03d70 TT |
179 | a single piece, so that callers need not distinguish between the |
180 | no-DW_OP_piece and one-DW_OP_piece cases. But expressions with | |
181 | no DW_OP_piece operations have no value to place in a piece's | |
182 | 'size' field; the size comes from the surrounding data. So the | |
183 | two cases need to be handled separately.) */ | |
1e467161 | 184 | std::vector<dwarf_expr_piece> pieces; |
595d2e30 | 185 | |
89b07335 SM |
186 | /* We evaluate the expression in the context of this objfile. */ |
187 | dwarf2_per_objfile *per_objfile; | |
188 | ||
192ca6d8 TT |
189 | /* Return the value of register number REGNUM (a DWARF register number), |
190 | read as an address. */ | |
191 | virtual CORE_ADDR read_addr_from_reg (int regnum) = 0; | |
192 | ||
193 | /* Return a value of type TYPE, stored in register number REGNUM | |
194 | of the frame associated to the given BATON. | |
195 | ||
196 | REGNUM is a DWARF register number. */ | |
197 | virtual struct value *get_reg_value (struct type *type, int regnum) = 0; | |
198 | ||
199 | /* Read LENGTH bytes at ADDR into BUF. */ | |
200 | virtual void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t length) = 0; | |
201 | ||
202 | /* Return the location expression for the frame base attribute, in | |
203 | START and LENGTH. The result must be live until the current | |
204 | expression evaluation is complete. */ | |
befbff86 | 205 | virtual void get_frame_base (const gdb_byte **start, size_t *length) = 0; |
192ca6d8 TT |
206 | |
207 | /* Return the CFA for the frame. */ | |
befbff86 | 208 | virtual CORE_ADDR get_frame_cfa () = 0; |
192ca6d8 TT |
209 | |
210 | /* Return the PC for the frame. */ | |
211 | virtual CORE_ADDR get_frame_pc () | |
212 | { | |
216f72a1 | 213 | error (_("%s is invalid in this context"), "DW_OP_implicit_pointer"); |
192ca6d8 TT |
214 | } |
215 | ||
216 | /* Return the thread-local storage address for | |
217 | DW_OP_GNU_push_tls_address or DW_OP_form_tls_address. */ | |
befbff86 | 218 | virtual CORE_ADDR get_tls_address (CORE_ADDR offset) = 0; |
192ca6d8 TT |
219 | |
220 | /* Execute DW_AT_location expression for the DWARF expression | |
9c541725 | 221 | subroutine in the DIE at DIE_CU_OFF in the CU. Do not touch |
192ca6d8 TT |
222 | STACK while it being passed to and returned from the called DWARF |
223 | subroutine. */ | |
9c541725 | 224 | virtual void dwarf_call (cu_offset die_cu_off) = 0; |
192ca6d8 | 225 | |
a6b786da KB |
226 | /* Execute "variable value" operation on the DIE at SECT_OFF. */ |
227 | virtual struct value *dwarf_variable_value (sect_offset sect_off) = 0; | |
228 | ||
9c541725 PA |
229 | /* Return the base type given by the indicated DIE at DIE_CU_OFF. |
230 | This can throw an exception if the DIE is invalid or does not | |
231 | represent a base type. SIZE is non-zero if this function should | |
232 | verify that the resulting type has the correct size. */ | |
233 | virtual struct type *get_base_type (cu_offset die_cu_off, int size) | |
192ca6d8 TT |
234 | { |
235 | /* Anything will do. */ | |
236 | return builtin_type (this->gdbarch)->builtin_int; | |
237 | } | |
238 | ||
216f72a1 | 239 | /* Push on DWARF stack an entry evaluated for DW_TAG_call_site's |
192ca6d8 | 240 | parameter matching KIND and KIND_U at the caller of specified BATON. |
216f72a1 JK |
241 | If DEREF_SIZE is not -1 then use DW_AT_call_data_value instead of |
242 | DW_AT_call_value. */ | |
192ca6d8 TT |
243 | virtual void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind, |
244 | union call_site_parameter_u kind_u, | |
befbff86 | 245 | int deref_size) = 0; |
192ca6d8 | 246 | |
336d760d | 247 | /* Return the address indexed by DW_OP_addrx or DW_OP_GNU_addr_index. |
192ca6d8 | 248 | This can throw an exception if the index is out of range. */ |
befbff86 | 249 | virtual CORE_ADDR get_addr_index (unsigned int index) = 0; |
192ca6d8 TT |
250 | |
251 | /* Return the `object address' for DW_OP_push_object_address. */ | |
befbff86 | 252 | virtual CORE_ADDR get_object_address () = 0; |
192ca6d8 | 253 | |
595d2e30 TT |
254 | private: |
255 | ||
256 | struct type *address_type () const; | |
69009882 | 257 | void push (struct value *value, bool in_stack_memory); |
eccd80d6 | 258 | bool stack_empty_p () const; |
595d2e30 | 259 | void add_piece (ULONGEST size, ULONGEST offset); |
595d2e30 TT |
260 | void execute_stack_op (const gdb_byte *op_ptr, const gdb_byte *op_end); |
261 | void pop (); | |
87808bd6 JB |
262 | }; |
263 | ||
3cf03773 TT |
264 | void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, |
265 | const char *); | |
266 | ||
8e3b41a9 | 267 | int dwarf_block_to_dwarf_reg (const gdb_byte *buf, const gdb_byte *buf_end); |
523f3620 | 268 | |
a471c594 JK |
269 | int dwarf_block_to_dwarf_reg_deref (const gdb_byte *buf, |
270 | const gdb_byte *buf_end, | |
271 | CORE_ADDR *deref_size_return); | |
272 | ||
e18b2753 JK |
273 | int dwarf_block_to_fb_offset (const gdb_byte *buf, const gdb_byte *buf_end, |
274 | CORE_ADDR *fb_offset_return); | |
275 | ||
276 | int dwarf_block_to_sp_offset (struct gdbarch *gdbarch, const gdb_byte *buf, | |
277 | const gdb_byte *buf_end, | |
278 | CORE_ADDR *sp_offset_return); | |
279 | ||
f664829e DE |
280 | /* Wrappers around the leb128 reader routines to simplify them for our |
281 | purposes. */ | |
282 | ||
283 | static inline const gdb_byte * | |
284 | gdb_read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
9fccedf7 | 285 | uint64_t *r) |
f664829e | 286 | { |
9fccedf7 | 287 | size_t bytes_read = read_uleb128_to_uint64 (buf, buf_end, r); |
f664829e DE |
288 | |
289 | if (bytes_read == 0) | |
290 | return NULL; | |
291 | return buf + bytes_read; | |
292 | } | |
293 | ||
294 | static inline const gdb_byte * | |
295 | gdb_read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
9fccedf7 | 296 | int64_t *r) |
f664829e | 297 | { |
9fccedf7 | 298 | size_t bytes_read = read_sleb128_to_int64 (buf, buf_end, r); |
f664829e DE |
299 | |
300 | if (bytes_read == 0) | |
301 | return NULL; | |
302 | return buf + bytes_read; | |
303 | } | |
304 | ||
305 | static inline const gdb_byte * | |
306 | gdb_skip_leb128 (const gdb_byte *buf, const gdb_byte *buf_end) | |
307 | { | |
308 | size_t bytes_read = skip_leb128 (buf, buf_end); | |
309 | ||
310 | if (bytes_read == 0) | |
311 | return NULL; | |
312 | return buf + bytes_read; | |
313 | } | |
314 | ||
315 | extern const gdb_byte *safe_read_uleb128 (const gdb_byte *buf, | |
316 | const gdb_byte *buf_end, | |
9fccedf7 | 317 | uint64_t *r); |
f664829e DE |
318 | |
319 | extern const gdb_byte *safe_read_sleb128 (const gdb_byte *buf, | |
320 | const gdb_byte *buf_end, | |
9fccedf7 | 321 | int64_t *r); |
f664829e DE |
322 | |
323 | extern const gdb_byte *safe_skip_leb128 (const gdb_byte *buf, | |
324 | const gdb_byte *buf_end); | |
325 | ||
852483bc | 326 | #endif /* dwarf2expr.h */ |