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852483bc MK |
1 | /* DWARF 2 Expression Evaluator. |
2 | ||
61baf725 | 3 | Copyright (C) 2001-2017 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 | ||
f664829e | 25 | #include "leb128.h" |
836bf454 | 26 | #include "gdbtypes.h" |
f664829e | 27 | |
cec03d70 TT |
28 | /* The location of a value. */ |
29 | enum dwarf_value_location | |
30 | { | |
44353522 DE |
31 | /* The piece is in memory. |
32 | The value on the dwarf stack is its address. */ | |
cec03d70 | 33 | DWARF_VALUE_MEMORY, |
44353522 DE |
34 | |
35 | /* The piece is in a register. | |
36 | The value on the dwarf stack is the register number. */ | |
cec03d70 | 37 | DWARF_VALUE_REGISTER, |
44353522 DE |
38 | |
39 | /* The piece is on the dwarf stack. */ | |
cec03d70 | 40 | DWARF_VALUE_STACK, |
44353522 | 41 | |
cec03d70 | 42 | /* The piece is a literal. */ |
cb826367 TT |
43 | DWARF_VALUE_LITERAL, |
44 | ||
45 | /* The piece was optimized out. */ | |
8cf6f0b1 TT |
46 | DWARF_VALUE_OPTIMIZED_OUT, |
47 | ||
48 | /* The piece is an implicit pointer. */ | |
49 | DWARF_VALUE_IMPLICIT_POINTER | |
cec03d70 TT |
50 | }; |
51 | ||
1e467161 SM |
52 | /* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */ |
53 | struct dwarf_expr_piece | |
54 | { | |
55 | enum dwarf_value_location location; | |
56 | ||
57 | union | |
58 | { | |
59 | struct | |
60 | { | |
61 | /* This piece's address, for DWARF_VALUE_MEMORY pieces. */ | |
62 | CORE_ADDR addr; | |
63 | /* Non-zero if the piece is known to be in memory and on | |
64 | the program's stack. */ | |
69009882 | 65 | bool in_stack_memory; |
1e467161 SM |
66 | } mem; |
67 | ||
68 | /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */ | |
69 | int regno; | |
70 | ||
71 | /* The piece's literal value, for DWARF_VALUE_STACK pieces. */ | |
72 | struct value *value; | |
73 | ||
74 | struct | |
75 | { | |
76 | /* A pointer to the data making up this piece, | |
77 | for DWARF_VALUE_LITERAL pieces. */ | |
78 | const gdb_byte *data; | |
79 | /* The length of the available data. */ | |
80 | ULONGEST length; | |
81 | } literal; | |
82 | ||
83 | /* Used for DWARF_VALUE_IMPLICIT_POINTER. */ | |
84 | struct | |
85 | { | |
86 | /* The referent DIE from DW_OP_implicit_pointer. */ | |
87 | sect_offset die_sect_off; | |
88 | /* The byte offset into the resulting data. */ | |
89 | LONGEST offset; | |
90 | } ptr; | |
91 | } v; | |
92 | ||
93 | /* The length of the piece, in bits. */ | |
94 | ULONGEST size; | |
95 | /* The piece offset, in bits. */ | |
96 | ULONGEST offset; | |
97 | }; | |
98 | ||
44353522 DE |
99 | /* The dwarf expression stack. */ |
100 | ||
101 | struct dwarf_stack_value | |
102 | { | |
d185219d SM |
103 | dwarf_stack_value (struct value *value_, int in_stack_memory_) |
104 | : value (value_), in_stack_memory (in_stack_memory_) | |
105 | {} | |
106 | ||
8a9b8146 | 107 | struct value *value; |
44353522 | 108 | |
69009882 SM |
109 | /* True if the piece is in memory and is known to be on the program's stack. |
110 | It is always ok to set this to zero. This is used, for example, to | |
111 | optimize memory access from the target. It can vastly speed up backtraces | |
112 | on long latency connections when "set stack-cache on". */ | |
113 | bool in_stack_memory; | |
44353522 DE |
114 | }; |
115 | ||
4c2df51b DJ |
116 | /* The expression evaluator works with a dwarf_expr_context, describing |
117 | its current state and its callbacks. */ | |
118 | struct dwarf_expr_context | |
119 | { | |
718b9626 | 120 | dwarf_expr_context (); |
d185219d | 121 | virtual ~dwarf_expr_context () = default; |
718b9626 | 122 | |
69009882 | 123 | void push_address (CORE_ADDR value, bool in_stack_memory); |
595d2e30 TT |
124 | void eval (const gdb_byte *addr, size_t len); |
125 | struct value *fetch (int n); | |
126 | CORE_ADDR fetch_address (int n); | |
69009882 | 127 | bool fetch_in_stack_memory (int n); |
595d2e30 | 128 | |
d185219d SM |
129 | /* The stack of values. */ |
130 | std::vector<dwarf_stack_value> stack; | |
4c2df51b | 131 | |
f7fd4728 UW |
132 | /* Target architecture to use for address operations. */ |
133 | struct gdbarch *gdbarch; | |
134 | ||
ae0d2f24 UW |
135 | /* Target address size in bytes. */ |
136 | int addr_size; | |
137 | ||
181cebd4 JK |
138 | /* DW_FORM_ref_addr size in bytes. If -1 DWARF is executed from a frame |
139 | context and operations depending on DW_FORM_ref_addr are not allowed. */ | |
140 | int ref_addr_size; | |
141 | ||
49f6c839 | 142 | /* Offset used to relocate DW_OP_addr and DW_OP_GNU_addr_index arguments. */ |
ac56253d TT |
143 | CORE_ADDR offset; |
144 | ||
4c2df51b DJ |
145 | /* The current depth of dwarf expression recursion, via DW_OP_call*, |
146 | DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum | |
147 | depth we'll tolerate before raising an error. */ | |
148 | int recursion_depth, max_recursion_depth; | |
149 | ||
cec03d70 TT |
150 | /* Location of the value. */ |
151 | enum dwarf_value_location location; | |
152 | ||
766062f6 | 153 | /* For DWARF_VALUE_LITERAL, the current literal value's length and |
8cf6f0b1 | 154 | data. For DWARF_VALUE_IMPLICIT_POINTER, LEN is the offset of the |
8b9737bf | 155 | target DIE of sect_offset kind. */ |
cec03d70 | 156 | ULONGEST len; |
0d45f56e | 157 | const gdb_byte *data; |
87808bd6 | 158 | |
42be36b3 CT |
159 | /* Initialization status of variable: Non-zero if variable has been |
160 | initialized; zero otherwise. */ | |
161 | int initialized; | |
162 | ||
1e467161 | 163 | /* A vector of pieces. |
87808bd6 JB |
164 | |
165 | Each time DW_OP_piece is executed, we add a new element to the | |
166 | end of this array, recording the current top of the stack, the | |
cec03d70 | 167 | current location, and the size given as the operand to |
44353522 | 168 | DW_OP_piece. We then pop the top value from the stack, reset the |
cec03d70 | 169 | location, and resume evaluation. |
87808bd6 JB |
170 | |
171 | The Dwarf spec doesn't say whether DW_OP_piece pops the top value | |
172 | from the stack. We do, ensuring that clients of this interface | |
173 | expecting to see a value left on the top of the stack (say, code | |
174 | evaluating frame base expressions or CFA's specified with | |
175 | DW_CFA_def_cfa_expression) will get an error if the expression | |
176 | actually marks all the values it computes as pieces. | |
177 | ||
178 | If an expression never uses DW_OP_piece, num_pieces will be zero. | |
179 | (It would be nice to present these cases as expressions yielding | |
cec03d70 TT |
180 | a single piece, so that callers need not distinguish between the |
181 | no-DW_OP_piece and one-DW_OP_piece cases. But expressions with | |
182 | no DW_OP_piece operations have no value to place in a piece's | |
183 | 'size' field; the size comes from the surrounding data. So the | |
184 | two cases need to be handled separately.) */ | |
1e467161 | 185 | std::vector<dwarf_expr_piece> pieces; |
595d2e30 | 186 | |
192ca6d8 TT |
187 | /* Return the value of register number REGNUM (a DWARF register number), |
188 | read as an address. */ | |
189 | virtual CORE_ADDR read_addr_from_reg (int regnum) = 0; | |
190 | ||
191 | /* Return a value of type TYPE, stored in register number REGNUM | |
192 | of the frame associated to the given BATON. | |
193 | ||
194 | REGNUM is a DWARF register number. */ | |
195 | virtual struct value *get_reg_value (struct type *type, int regnum) = 0; | |
196 | ||
197 | /* Read LENGTH bytes at ADDR into BUF. */ | |
198 | virtual void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t length) = 0; | |
199 | ||
200 | /* Return the location expression for the frame base attribute, in | |
201 | START and LENGTH. The result must be live until the current | |
202 | expression evaluation is complete. */ | |
befbff86 | 203 | virtual void get_frame_base (const gdb_byte **start, size_t *length) = 0; |
192ca6d8 TT |
204 | |
205 | /* Return the CFA for the frame. */ | |
befbff86 | 206 | virtual CORE_ADDR get_frame_cfa () = 0; |
192ca6d8 TT |
207 | |
208 | /* Return the PC for the frame. */ | |
209 | virtual CORE_ADDR get_frame_pc () | |
210 | { | |
216f72a1 | 211 | error (_("%s is invalid in this context"), "DW_OP_implicit_pointer"); |
192ca6d8 TT |
212 | } |
213 | ||
214 | /* Return the thread-local storage address for | |
215 | DW_OP_GNU_push_tls_address or DW_OP_form_tls_address. */ | |
befbff86 | 216 | virtual CORE_ADDR get_tls_address (CORE_ADDR offset) = 0; |
192ca6d8 TT |
217 | |
218 | /* Execute DW_AT_location expression for the DWARF expression | |
9c541725 | 219 | subroutine in the DIE at DIE_CU_OFF in the CU. Do not touch |
192ca6d8 TT |
220 | STACK while it being passed to and returned from the called DWARF |
221 | subroutine. */ | |
9c541725 | 222 | virtual void dwarf_call (cu_offset die_cu_off) = 0; |
192ca6d8 | 223 | |
9c541725 PA |
224 | /* Return the base type given by the indicated DIE at DIE_CU_OFF. |
225 | This can throw an exception if the DIE is invalid or does not | |
226 | represent a base type. SIZE is non-zero if this function should | |
227 | verify that the resulting type has the correct size. */ | |
228 | virtual struct type *get_base_type (cu_offset die_cu_off, int size) | |
192ca6d8 TT |
229 | { |
230 | /* Anything will do. */ | |
231 | return builtin_type (this->gdbarch)->builtin_int; | |
232 | } | |
233 | ||
216f72a1 | 234 | /* Push on DWARF stack an entry evaluated for DW_TAG_call_site's |
192ca6d8 | 235 | parameter matching KIND and KIND_U at the caller of specified BATON. |
216f72a1 JK |
236 | If DEREF_SIZE is not -1 then use DW_AT_call_data_value instead of |
237 | DW_AT_call_value. */ | |
192ca6d8 TT |
238 | virtual void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind, |
239 | union call_site_parameter_u kind_u, | |
befbff86 | 240 | int deref_size) = 0; |
192ca6d8 TT |
241 | |
242 | /* Return the address indexed by DW_OP_GNU_addr_index. | |
243 | This can throw an exception if the index is out of range. */ | |
befbff86 | 244 | virtual CORE_ADDR get_addr_index (unsigned int index) = 0; |
192ca6d8 TT |
245 | |
246 | /* Return the `object address' for DW_OP_push_object_address. */ | |
befbff86 | 247 | virtual CORE_ADDR get_object_address () = 0; |
192ca6d8 | 248 | |
595d2e30 TT |
249 | private: |
250 | ||
251 | struct type *address_type () const; | |
69009882 | 252 | void push (struct value *value, bool in_stack_memory); |
eccd80d6 | 253 | bool stack_empty_p () const; |
595d2e30 | 254 | void add_piece (ULONGEST size, ULONGEST offset); |
595d2e30 TT |
255 | void execute_stack_op (const gdb_byte *op_ptr, const gdb_byte *op_end); |
256 | void pop (); | |
87808bd6 JB |
257 | }; |
258 | ||
3cf03773 TT |
259 | void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, |
260 | const char *); | |
261 | ||
8e3b41a9 | 262 | int dwarf_block_to_dwarf_reg (const gdb_byte *buf, const gdb_byte *buf_end); |
523f3620 | 263 | |
a471c594 JK |
264 | int dwarf_block_to_dwarf_reg_deref (const gdb_byte *buf, |
265 | const gdb_byte *buf_end, | |
266 | CORE_ADDR *deref_size_return); | |
267 | ||
e18b2753 JK |
268 | int dwarf_block_to_fb_offset (const gdb_byte *buf, const gdb_byte *buf_end, |
269 | CORE_ADDR *fb_offset_return); | |
270 | ||
271 | int dwarf_block_to_sp_offset (struct gdbarch *gdbarch, const gdb_byte *buf, | |
272 | const gdb_byte *buf_end, | |
273 | CORE_ADDR *sp_offset_return); | |
274 | ||
f664829e DE |
275 | /* Wrappers around the leb128 reader routines to simplify them for our |
276 | purposes. */ | |
277 | ||
278 | static inline const gdb_byte * | |
279 | gdb_read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
9fccedf7 | 280 | uint64_t *r) |
f664829e | 281 | { |
9fccedf7 | 282 | size_t bytes_read = read_uleb128_to_uint64 (buf, buf_end, r); |
f664829e DE |
283 | |
284 | if (bytes_read == 0) | |
285 | return NULL; | |
286 | return buf + bytes_read; | |
287 | } | |
288 | ||
289 | static inline const gdb_byte * | |
290 | gdb_read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
9fccedf7 | 291 | int64_t *r) |
f664829e | 292 | { |
9fccedf7 | 293 | size_t bytes_read = read_sleb128_to_int64 (buf, buf_end, r); |
f664829e DE |
294 | |
295 | if (bytes_read == 0) | |
296 | return NULL; | |
297 | return buf + bytes_read; | |
298 | } | |
299 | ||
300 | static inline const gdb_byte * | |
301 | gdb_skip_leb128 (const gdb_byte *buf, const gdb_byte *buf_end) | |
302 | { | |
303 | size_t bytes_read = skip_leb128 (buf, buf_end); | |
304 | ||
305 | if (bytes_read == 0) | |
306 | return NULL; | |
307 | return buf + bytes_read; | |
308 | } | |
309 | ||
310 | extern const gdb_byte *safe_read_uleb128 (const gdb_byte *buf, | |
311 | const gdb_byte *buf_end, | |
9fccedf7 | 312 | uint64_t *r); |
f664829e DE |
313 | |
314 | extern const gdb_byte *safe_read_sleb128 (const gdb_byte *buf, | |
315 | const gdb_byte *buf_end, | |
9fccedf7 | 316 | int64_t *r); |
f664829e DE |
317 | |
318 | extern const gdb_byte *safe_skip_leb128 (const gdb_byte *buf, | |
319 | const gdb_byte *buf_end); | |
320 | ||
852483bc | 321 | #endif /* dwarf2expr.h */ |