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852483bc MK |
1 | /* DWARF 2 Expression Evaluator. |
2 | ||
0b302171 JB |
3 | Copyright (C) 2001-2003, 2005, 2007-2012 Free Software Foundation, |
4 | Inc. | |
852483bc MK |
5 | |
6 | Contributed by Daniel Berlin <dan@dberlin.org>. | |
7 | ||
4c2df51b DJ |
8 | This file is part of GDB. |
9 | ||
10 | This program is free software; you can redistribute it and/or modify | |
11 | it under the terms of the GNU General Public License as published by | |
a9762ec7 | 12 | the Free Software Foundation; either version 3 of the License, or |
4c2df51b DJ |
13 | (at your option) any later version. |
14 | ||
15 | This program is distributed in the hope that it will be useful, | |
16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | GNU General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU General Public License | |
a9762ec7 | 21 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
4c2df51b DJ |
22 | |
23 | #if !defined (DWARF2EXPR_H) | |
24 | #define DWARF2EXPR_H | |
25 | ||
f664829e DE |
26 | #include "leb128.h" |
27 | ||
9e8b7a03 | 28 | struct dwarf_expr_context; |
24c5c679 JK |
29 | enum call_site_parameter_kind; |
30 | union call_site_parameter_u; | |
9e8b7a03 | 31 | |
b64f50a1 JK |
32 | /* Offset relative to the start of its containing CU (compilation unit). */ |
33 | typedef struct | |
34 | { | |
35 | unsigned int cu_off; | |
36 | } cu_offset; | |
37 | ||
38 | /* Offset relative to the start of its .debug_info or .debug_types section. */ | |
39 | typedef struct | |
40 | { | |
41 | unsigned int sect_off; | |
42 | } sect_offset; | |
43 | ||
9e8b7a03 JK |
44 | /* Virtual method table for struct dwarf_expr_context below. */ |
45 | ||
46 | struct dwarf_expr_context_funcs | |
47 | { | |
48 | /* Return the value of register number REGNUM. */ | |
49 | CORE_ADDR (*read_reg) (void *baton, int regnum); | |
50 | ||
51 | /* Read LENGTH bytes at ADDR into BUF. */ | |
52 | void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length); | |
53 | ||
54 | /* Return the location expression for the frame base attribute, in | |
55 | START and LENGTH. The result must be live until the current | |
56 | expression evaluation is complete. */ | |
57 | void (*get_frame_base) (void *baton, const gdb_byte **start, size_t *length); | |
58 | ||
59 | /* Return the CFA for the frame. */ | |
60 | CORE_ADDR (*get_frame_cfa) (void *baton); | |
61 | ||
62 | /* Return the PC for the frame. */ | |
63 | CORE_ADDR (*get_frame_pc) (void *baton); | |
64 | ||
65 | /* Return the thread-local storage address for | |
66 | DW_OP_GNU_push_tls_address. */ | |
67 | CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset); | |
68 | ||
69 | /* Execute DW_AT_location expression for the DWARF expression subroutine in | |
70 | the DIE at DIE_OFFSET in the CU from CTX. Do not touch STACK while it | |
71 | being passed to and returned from the called DWARF subroutine. */ | |
b64f50a1 | 72 | void (*dwarf_call) (struct dwarf_expr_context *ctx, cu_offset die_offset); |
9e8b7a03 JK |
73 | |
74 | /* Return the base type given by the indicated DIE. This can throw | |
75 | an exception if the DIE is invalid or does not represent a base | |
76 | type. If can also be NULL in the special case where the | |
77 | callbacks are not performing evaluation, and thus it is | |
78 | meaningful to substitute a stub type of the correct size. */ | |
b64f50a1 | 79 | struct type *(*get_base_type) (struct dwarf_expr_context *ctx, cu_offset die); |
9e8b7a03 | 80 | |
8e3b41a9 | 81 | /* Push on DWARF stack an entry evaluated for DW_TAG_GNU_call_site's |
24c5c679 JK |
82 | parameter matching KIND and KIND_U at the caller of specified BATON. |
83 | If DEREF_SIZE is not -1 then use DW_AT_GNU_call_site_data_value instead of | |
84 | DW_AT_GNU_call_site_value. */ | |
8e3b41a9 | 85 | void (*push_dwarf_reg_entry_value) (struct dwarf_expr_context *ctx, |
24c5c679 JK |
86 | enum call_site_parameter_kind kind, |
87 | union call_site_parameter_u kind_u, | |
a471c594 | 88 | int deref_size); |
8e3b41a9 | 89 | |
3019eac3 DE |
90 | /* Return the address indexed by DW_OP_GNU_addr_index. |
91 | This can throw an exception if the index is out of range. */ | |
92 | CORE_ADDR (*get_addr_index) (void *baton, unsigned int index); | |
93 | ||
9e8b7a03 JK |
94 | #if 0 |
95 | /* Not yet implemented. */ | |
96 | ||
97 | /* Return the `object address' for DW_OP_push_object_address. */ | |
98 | CORE_ADDR (*get_object_address) (void *baton); | |
99 | #endif | |
100 | }; | |
101 | ||
cec03d70 TT |
102 | /* The location of a value. */ |
103 | enum dwarf_value_location | |
104 | { | |
44353522 DE |
105 | /* The piece is in memory. |
106 | The value on the dwarf stack is its address. */ | |
cec03d70 | 107 | DWARF_VALUE_MEMORY, |
44353522 DE |
108 | |
109 | /* The piece is in a register. | |
110 | The value on the dwarf stack is the register number. */ | |
cec03d70 | 111 | DWARF_VALUE_REGISTER, |
44353522 DE |
112 | |
113 | /* The piece is on the dwarf stack. */ | |
cec03d70 | 114 | DWARF_VALUE_STACK, |
44353522 | 115 | |
cec03d70 | 116 | /* The piece is a literal. */ |
cb826367 TT |
117 | DWARF_VALUE_LITERAL, |
118 | ||
119 | /* The piece was optimized out. */ | |
8cf6f0b1 TT |
120 | DWARF_VALUE_OPTIMIZED_OUT, |
121 | ||
122 | /* The piece is an implicit pointer. */ | |
123 | DWARF_VALUE_IMPLICIT_POINTER | |
cec03d70 TT |
124 | }; |
125 | ||
44353522 DE |
126 | /* The dwarf expression stack. */ |
127 | ||
128 | struct dwarf_stack_value | |
129 | { | |
8a9b8146 | 130 | struct value *value; |
44353522 DE |
131 | |
132 | /* Non-zero if the piece is in memory and is known to be | |
133 | on the program's stack. It is always ok to set this to zero. | |
134 | This is used, for example, to optimize memory access from the target. | |
135 | It can vastly speed up backtraces on long latency connections when | |
136 | "set stack-cache on". */ | |
137 | int in_stack_memory; | |
138 | }; | |
139 | ||
4c2df51b DJ |
140 | /* The expression evaluator works with a dwarf_expr_context, describing |
141 | its current state and its callbacks. */ | |
142 | struct dwarf_expr_context | |
143 | { | |
144 | /* The stack of values, allocated with xmalloc. */ | |
44353522 | 145 | struct dwarf_stack_value *stack; |
4c2df51b DJ |
146 | |
147 | /* The number of values currently pushed on the stack, and the | |
148 | number of elements allocated to the stack. */ | |
149 | int stack_len, stack_allocated; | |
150 | ||
f7fd4728 UW |
151 | /* Target architecture to use for address operations. */ |
152 | struct gdbarch *gdbarch; | |
153 | ||
ae0d2f24 UW |
154 | /* Target address size in bytes. */ |
155 | int addr_size; | |
156 | ||
181cebd4 JK |
157 | /* DW_FORM_ref_addr size in bytes. If -1 DWARF is executed from a frame |
158 | context and operations depending on DW_FORM_ref_addr are not allowed. */ | |
159 | int ref_addr_size; | |
160 | ||
ac56253d TT |
161 | /* Offset used to relocate DW_OP_addr argument. */ |
162 | CORE_ADDR offset; | |
163 | ||
4c2df51b DJ |
164 | /* An opaque argument provided by the caller, which will be passed |
165 | to all of the callback functions. */ | |
166 | void *baton; | |
167 | ||
9e8b7a03 JK |
168 | /* Callback functions. */ |
169 | const struct dwarf_expr_context_funcs *funcs; | |
4c2df51b DJ |
170 | |
171 | /* The current depth of dwarf expression recursion, via DW_OP_call*, | |
172 | DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum | |
173 | depth we'll tolerate before raising an error. */ | |
174 | int recursion_depth, max_recursion_depth; | |
175 | ||
cec03d70 TT |
176 | /* Location of the value. */ |
177 | enum dwarf_value_location location; | |
178 | ||
766062f6 | 179 | /* For DWARF_VALUE_LITERAL, the current literal value's length and |
8cf6f0b1 | 180 | data. For DWARF_VALUE_IMPLICIT_POINTER, LEN is the offset of the |
b64f50a1 | 181 | target DIE of cu_offset kind. */ |
cec03d70 | 182 | ULONGEST len; |
0d45f56e | 183 | const gdb_byte *data; |
87808bd6 | 184 | |
42be36b3 CT |
185 | /* Initialization status of variable: Non-zero if variable has been |
186 | initialized; zero otherwise. */ | |
187 | int initialized; | |
188 | ||
87808bd6 JB |
189 | /* An array of pieces. PIECES points to its first element; |
190 | NUM_PIECES is its length. | |
191 | ||
192 | Each time DW_OP_piece is executed, we add a new element to the | |
193 | end of this array, recording the current top of the stack, the | |
cec03d70 | 194 | current location, and the size given as the operand to |
44353522 | 195 | DW_OP_piece. We then pop the top value from the stack, reset the |
cec03d70 | 196 | location, and resume evaluation. |
87808bd6 JB |
197 | |
198 | The Dwarf spec doesn't say whether DW_OP_piece pops the top value | |
199 | from the stack. We do, ensuring that clients of this interface | |
200 | expecting to see a value left on the top of the stack (say, code | |
201 | evaluating frame base expressions or CFA's specified with | |
202 | DW_CFA_def_cfa_expression) will get an error if the expression | |
203 | actually marks all the values it computes as pieces. | |
204 | ||
205 | If an expression never uses DW_OP_piece, num_pieces will be zero. | |
206 | (It would be nice to present these cases as expressions yielding | |
cec03d70 TT |
207 | a single piece, so that callers need not distinguish between the |
208 | no-DW_OP_piece and one-DW_OP_piece cases. But expressions with | |
209 | no DW_OP_piece operations have no value to place in a piece's | |
210 | 'size' field; the size comes from the surrounding data. So the | |
211 | two cases need to be handled separately.) */ | |
87808bd6 JB |
212 | int num_pieces; |
213 | struct dwarf_expr_piece *pieces; | |
214 | }; | |
215 | ||
216 | ||
d3b1e874 | 217 | /* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */ |
87808bd6 JB |
218 | struct dwarf_expr_piece |
219 | { | |
cec03d70 TT |
220 | enum dwarf_value_location location; |
221 | ||
222 | union | |
223 | { | |
44353522 DE |
224 | struct |
225 | { | |
f2c7657e UW |
226 | /* This piece's address, for DWARF_VALUE_MEMORY pieces. */ |
227 | CORE_ADDR addr; | |
44353522 DE |
228 | /* Non-zero if the piece is known to be in memory and on |
229 | the program's stack. */ | |
230 | int in_stack_memory; | |
f2c7657e UW |
231 | } mem; |
232 | ||
8a9b8146 TT |
233 | /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */ |
234 | int regno; | |
235 | ||
236 | /* The piece's literal value, for DWARF_VALUE_STACK pieces. */ | |
237 | struct value *value; | |
cec03d70 TT |
238 | |
239 | struct | |
240 | { | |
f2c7657e UW |
241 | /* A pointer to the data making up this piece, |
242 | for DWARF_VALUE_LITERAL pieces. */ | |
0d45f56e | 243 | const gdb_byte *data; |
cec03d70 TT |
244 | /* The length of the available data. */ |
245 | ULONGEST length; | |
246 | } literal; | |
8cf6f0b1 TT |
247 | |
248 | /* Used for DWARF_VALUE_IMPLICIT_POINTER. */ | |
249 | struct | |
250 | { | |
251 | /* The referent DIE from DW_OP_GNU_implicit_pointer. */ | |
b64f50a1 | 252 | cu_offset die; |
8cf6f0b1 TT |
253 | /* The byte offset into the resulting data. */ |
254 | LONGEST offset; | |
255 | } ptr; | |
cec03d70 | 256 | } v; |
87808bd6 | 257 | |
d3b1e874 | 258 | /* The length of the piece, in bits. */ |
87808bd6 | 259 | ULONGEST size; |
d3b1e874 TT |
260 | /* The piece offset, in bits. */ |
261 | ULONGEST offset; | |
4c2df51b DJ |
262 | }; |
263 | ||
b9362cc7 | 264 | struct dwarf_expr_context *new_dwarf_expr_context (void); |
4c2df51b | 265 | void free_dwarf_expr_context (struct dwarf_expr_context *ctx); |
4a227398 TT |
266 | struct cleanup * |
267 | make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx); | |
4c2df51b | 268 | |
8a9b8146 TT |
269 | void dwarf_expr_push_address (struct dwarf_expr_context *ctx, |
270 | CORE_ADDR value, | |
271 | int in_stack_memory); | |
0d45f56e | 272 | void dwarf_expr_eval (struct dwarf_expr_context *ctx, const gdb_byte *addr, |
4c2df51b | 273 | size_t len); |
8a9b8146 | 274 | struct value *dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n); |
f2c7657e | 275 | CORE_ADDR dwarf_expr_fetch_address (struct dwarf_expr_context *ctx, int n); |
44353522 | 276 | int dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context *ctx, int n); |
4c2df51b | 277 | |
3cf03773 TT |
278 | void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, |
279 | const char *); | |
280 | ||
523f3620 JK |
281 | /* Stub dwarf_expr_context_funcs implementations. */ |
282 | ||
283 | void ctx_no_get_frame_base (void *baton, const gdb_byte **start, | |
284 | size_t *length); | |
285 | CORE_ADDR ctx_no_get_frame_cfa (void *baton); | |
286 | CORE_ADDR ctx_no_get_frame_pc (void *baton); | |
287 | CORE_ADDR ctx_no_get_tls_address (void *baton, CORE_ADDR offset); | |
b64f50a1 JK |
288 | void ctx_no_dwarf_call (struct dwarf_expr_context *ctx, cu_offset die_offset); |
289 | struct type *ctx_no_get_base_type (struct dwarf_expr_context *ctx, | |
290 | cu_offset die); | |
8e3b41a9 | 291 | void ctx_no_push_dwarf_reg_entry_value (struct dwarf_expr_context *ctx, |
24c5c679 JK |
292 | enum call_site_parameter_kind kind, |
293 | union call_site_parameter_u kind_u, | |
a471c594 | 294 | int deref_size); |
3019eac3 | 295 | CORE_ADDR ctx_no_get_addr_index (void *baton, unsigned int index); |
8e3b41a9 JK |
296 | |
297 | int dwarf_block_to_dwarf_reg (const gdb_byte *buf, const gdb_byte *buf_end); | |
523f3620 | 298 | |
a471c594 JK |
299 | int dwarf_block_to_dwarf_reg_deref (const gdb_byte *buf, |
300 | const gdb_byte *buf_end, | |
301 | CORE_ADDR *deref_size_return); | |
302 | ||
e18b2753 JK |
303 | int dwarf_block_to_fb_offset (const gdb_byte *buf, const gdb_byte *buf_end, |
304 | CORE_ADDR *fb_offset_return); | |
305 | ||
306 | int dwarf_block_to_sp_offset (struct gdbarch *gdbarch, const gdb_byte *buf, | |
307 | const gdb_byte *buf_end, | |
308 | CORE_ADDR *sp_offset_return); | |
309 | ||
f664829e DE |
310 | /* Wrappers around the leb128 reader routines to simplify them for our |
311 | purposes. */ | |
312 | ||
313 | static inline const gdb_byte * | |
314 | gdb_read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
9fccedf7 | 315 | uint64_t *r) |
f664829e | 316 | { |
9fccedf7 | 317 | size_t bytes_read = read_uleb128_to_uint64 (buf, buf_end, r); |
f664829e DE |
318 | |
319 | if (bytes_read == 0) | |
320 | return NULL; | |
321 | return buf + bytes_read; | |
322 | } | |
323 | ||
324 | static inline const gdb_byte * | |
325 | gdb_read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
9fccedf7 | 326 | int64_t *r) |
f664829e | 327 | { |
9fccedf7 | 328 | size_t bytes_read = read_sleb128_to_int64 (buf, buf_end, r); |
f664829e DE |
329 | |
330 | if (bytes_read == 0) | |
331 | return NULL; | |
332 | return buf + bytes_read; | |
333 | } | |
334 | ||
335 | static inline const gdb_byte * | |
336 | gdb_skip_leb128 (const gdb_byte *buf, const gdb_byte *buf_end) | |
337 | { | |
338 | size_t bytes_read = skip_leb128 (buf, buf_end); | |
339 | ||
340 | if (bytes_read == 0) | |
341 | return NULL; | |
342 | return buf + bytes_read; | |
343 | } | |
344 | ||
345 | extern const gdb_byte *safe_read_uleb128 (const gdb_byte *buf, | |
346 | const gdb_byte *buf_end, | |
9fccedf7 | 347 | uint64_t *r); |
f664829e DE |
348 | |
349 | extern const gdb_byte *safe_read_sleb128 (const gdb_byte *buf, | |
350 | const gdb_byte *buf_end, | |
9fccedf7 | 351 | int64_t *r); |
f664829e DE |
352 | |
353 | extern const gdb_byte *safe_skip_leb128 (const gdb_byte *buf, | |
354 | const gdb_byte *buf_end); | |
355 | ||
852483bc | 356 | #endif /* dwarf2expr.h */ |