Commit | Line | Data |
---|---|---|
852483bc MK |
1 | /* DWARF 2 Expression Evaluator. |
2 | ||
ecd75fc8 | 3 | Copyright (C) 2001-2014 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 | |
9e8b7a03 | 28 | struct dwarf_expr_context; |
b64f50a1 | 29 | |
9e8b7a03 JK |
30 | /* Virtual method table for struct dwarf_expr_context below. */ |
31 | ||
32 | struct dwarf_expr_context_funcs | |
33 | { | |
0acf8b65 JB |
34 | /* Return the value of register number REGNUM (a DWARF register number), |
35 | read as an address. */ | |
b1370418 | 36 | CORE_ADDR (*read_addr_from_reg) (void *baton, int regnum); |
9e8b7a03 | 37 | |
0acf8b65 JB |
38 | /* Return a value of type TYPE, stored in register number REGNUM |
39 | of the frame associated to the given BATON. | |
40 | ||
41 | REGNUM is a DWARF register number. */ | |
42 | struct value *(*get_reg_value) (void *baton, struct type *type, int regnum); | |
43 | ||
9e8b7a03 JK |
44 | /* Read LENGTH bytes at ADDR into BUF. */ |
45 | void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length); | |
46 | ||
47 | /* Return the location expression for the frame base attribute, in | |
48 | START and LENGTH. The result must be live until the current | |
49 | expression evaluation is complete. */ | |
50 | void (*get_frame_base) (void *baton, const gdb_byte **start, size_t *length); | |
51 | ||
52 | /* Return the CFA for the frame. */ | |
53 | CORE_ADDR (*get_frame_cfa) (void *baton); | |
54 | ||
55 | /* Return the PC for the frame. */ | |
56 | CORE_ADDR (*get_frame_pc) (void *baton); | |
57 | ||
58 | /* Return the thread-local storage address for | |
59 | DW_OP_GNU_push_tls_address. */ | |
60 | CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset); | |
61 | ||
62 | /* Execute DW_AT_location expression for the DWARF expression subroutine in | |
63 | the DIE at DIE_OFFSET in the CU from CTX. Do not touch STACK while it | |
64 | being passed to and returned from the called DWARF subroutine. */ | |
b64f50a1 | 65 | void (*dwarf_call) (struct dwarf_expr_context *ctx, cu_offset die_offset); |
9e8b7a03 JK |
66 | |
67 | /* Return the base type given by the indicated DIE. This can throw | |
68 | an exception if the DIE is invalid or does not represent a base | |
69 | type. If can also be NULL in the special case where the | |
70 | callbacks are not performing evaluation, and thus it is | |
71 | meaningful to substitute a stub type of the correct size. */ | |
b64f50a1 | 72 | struct type *(*get_base_type) (struct dwarf_expr_context *ctx, cu_offset die); |
9e8b7a03 | 73 | |
8e3b41a9 | 74 | /* Push on DWARF stack an entry evaluated for DW_TAG_GNU_call_site's |
24c5c679 JK |
75 | parameter matching KIND and KIND_U at the caller of specified BATON. |
76 | If DEREF_SIZE is not -1 then use DW_AT_GNU_call_site_data_value instead of | |
77 | DW_AT_GNU_call_site_value. */ | |
8e3b41a9 | 78 | void (*push_dwarf_reg_entry_value) (struct dwarf_expr_context *ctx, |
24c5c679 JK |
79 | enum call_site_parameter_kind kind, |
80 | union call_site_parameter_u kind_u, | |
a471c594 | 81 | int deref_size); |
8e3b41a9 | 82 | |
3019eac3 DE |
83 | /* Return the address indexed by DW_OP_GNU_addr_index. |
84 | This can throw an exception if the index is out of range. */ | |
85 | CORE_ADDR (*get_addr_index) (void *baton, unsigned int index); | |
86 | ||
9e8b7a03 JK |
87 | #if 0 |
88 | /* Not yet implemented. */ | |
89 | ||
90 | /* Return the `object address' for DW_OP_push_object_address. */ | |
91 | CORE_ADDR (*get_object_address) (void *baton); | |
92 | #endif | |
93 | }; | |
94 | ||
cec03d70 TT |
95 | /* The location of a value. */ |
96 | enum dwarf_value_location | |
97 | { | |
44353522 DE |
98 | /* The piece is in memory. |
99 | The value on the dwarf stack is its address. */ | |
cec03d70 | 100 | DWARF_VALUE_MEMORY, |
44353522 DE |
101 | |
102 | /* The piece is in a register. | |
103 | The value on the dwarf stack is the register number. */ | |
cec03d70 | 104 | DWARF_VALUE_REGISTER, |
44353522 DE |
105 | |
106 | /* The piece is on the dwarf stack. */ | |
cec03d70 | 107 | DWARF_VALUE_STACK, |
44353522 | 108 | |
cec03d70 | 109 | /* The piece is a literal. */ |
cb826367 TT |
110 | DWARF_VALUE_LITERAL, |
111 | ||
112 | /* The piece was optimized out. */ | |
8cf6f0b1 TT |
113 | DWARF_VALUE_OPTIMIZED_OUT, |
114 | ||
115 | /* The piece is an implicit pointer. */ | |
116 | DWARF_VALUE_IMPLICIT_POINTER | |
cec03d70 TT |
117 | }; |
118 | ||
44353522 DE |
119 | /* The dwarf expression stack. */ |
120 | ||
121 | struct dwarf_stack_value | |
122 | { | |
8a9b8146 | 123 | struct value *value; |
44353522 DE |
124 | |
125 | /* Non-zero if the piece is in memory and is known to be | |
126 | on the program's stack. It is always ok to set this to zero. | |
127 | This is used, for example, to optimize memory access from the target. | |
128 | It can vastly speed up backtraces on long latency connections when | |
129 | "set stack-cache on". */ | |
130 | int in_stack_memory; | |
131 | }; | |
132 | ||
4c2df51b DJ |
133 | /* The expression evaluator works with a dwarf_expr_context, describing |
134 | its current state and its callbacks. */ | |
135 | struct dwarf_expr_context | |
136 | { | |
137 | /* The stack of values, allocated with xmalloc. */ | |
44353522 | 138 | struct dwarf_stack_value *stack; |
4c2df51b DJ |
139 | |
140 | /* The number of values currently pushed on the stack, and the | |
141 | number of elements allocated to the stack. */ | |
142 | int stack_len, stack_allocated; | |
143 | ||
f7fd4728 UW |
144 | /* Target architecture to use for address operations. */ |
145 | struct gdbarch *gdbarch; | |
146 | ||
ae0d2f24 UW |
147 | /* Target address size in bytes. */ |
148 | int addr_size; | |
149 | ||
181cebd4 JK |
150 | /* DW_FORM_ref_addr size in bytes. If -1 DWARF is executed from a frame |
151 | context and operations depending on DW_FORM_ref_addr are not allowed. */ | |
152 | int ref_addr_size; | |
153 | ||
49f6c839 | 154 | /* Offset used to relocate DW_OP_addr and DW_OP_GNU_addr_index arguments. */ |
ac56253d TT |
155 | CORE_ADDR offset; |
156 | ||
4c2df51b DJ |
157 | /* An opaque argument provided by the caller, which will be passed |
158 | to all of the callback functions. */ | |
159 | void *baton; | |
160 | ||
9e8b7a03 JK |
161 | /* Callback functions. */ |
162 | const struct dwarf_expr_context_funcs *funcs; | |
4c2df51b DJ |
163 | |
164 | /* The current depth of dwarf expression recursion, via DW_OP_call*, | |
165 | DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum | |
166 | depth we'll tolerate before raising an error. */ | |
167 | int recursion_depth, max_recursion_depth; | |
168 | ||
cec03d70 TT |
169 | /* Location of the value. */ |
170 | enum dwarf_value_location location; | |
171 | ||
766062f6 | 172 | /* For DWARF_VALUE_LITERAL, the current literal value's length and |
8cf6f0b1 | 173 | data. For DWARF_VALUE_IMPLICIT_POINTER, LEN is the offset of the |
8b9737bf | 174 | target DIE of sect_offset kind. */ |
cec03d70 | 175 | ULONGEST len; |
0d45f56e | 176 | const gdb_byte *data; |
87808bd6 | 177 | |
42be36b3 CT |
178 | /* Initialization status of variable: Non-zero if variable has been |
179 | initialized; zero otherwise. */ | |
180 | int initialized; | |
181 | ||
87808bd6 JB |
182 | /* An array of pieces. PIECES points to its first element; |
183 | NUM_PIECES is its length. | |
184 | ||
185 | Each time DW_OP_piece is executed, we add a new element to the | |
186 | end of this array, recording the current top of the stack, the | |
cec03d70 | 187 | current location, and the size given as the operand to |
44353522 | 188 | DW_OP_piece. We then pop the top value from the stack, reset the |
cec03d70 | 189 | location, and resume evaluation. |
87808bd6 JB |
190 | |
191 | The Dwarf spec doesn't say whether DW_OP_piece pops the top value | |
192 | from the stack. We do, ensuring that clients of this interface | |
193 | expecting to see a value left on the top of the stack (say, code | |
194 | evaluating frame base expressions or CFA's specified with | |
195 | DW_CFA_def_cfa_expression) will get an error if the expression | |
196 | actually marks all the values it computes as pieces. | |
197 | ||
198 | If an expression never uses DW_OP_piece, num_pieces will be zero. | |
199 | (It would be nice to present these cases as expressions yielding | |
cec03d70 TT |
200 | a single piece, so that callers need not distinguish between the |
201 | no-DW_OP_piece and one-DW_OP_piece cases. But expressions with | |
202 | no DW_OP_piece operations have no value to place in a piece's | |
203 | 'size' field; the size comes from the surrounding data. So the | |
204 | two cases need to be handled separately.) */ | |
87808bd6 JB |
205 | int num_pieces; |
206 | struct dwarf_expr_piece *pieces; | |
207 | }; | |
208 | ||
209 | ||
d3b1e874 | 210 | /* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */ |
87808bd6 JB |
211 | struct dwarf_expr_piece |
212 | { | |
cec03d70 TT |
213 | enum dwarf_value_location location; |
214 | ||
215 | union | |
216 | { | |
44353522 DE |
217 | struct |
218 | { | |
f2c7657e UW |
219 | /* This piece's address, for DWARF_VALUE_MEMORY pieces. */ |
220 | CORE_ADDR addr; | |
44353522 DE |
221 | /* Non-zero if the piece is known to be in memory and on |
222 | the program's stack. */ | |
223 | int in_stack_memory; | |
f2c7657e UW |
224 | } mem; |
225 | ||
8a9b8146 TT |
226 | /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */ |
227 | int regno; | |
228 | ||
229 | /* The piece's literal value, for DWARF_VALUE_STACK pieces. */ | |
230 | struct value *value; | |
cec03d70 TT |
231 | |
232 | struct | |
233 | { | |
f2c7657e UW |
234 | /* A pointer to the data making up this piece, |
235 | for DWARF_VALUE_LITERAL pieces. */ | |
0d45f56e | 236 | const gdb_byte *data; |
cec03d70 TT |
237 | /* The length of the available data. */ |
238 | ULONGEST length; | |
239 | } literal; | |
8cf6f0b1 TT |
240 | |
241 | /* Used for DWARF_VALUE_IMPLICIT_POINTER. */ | |
242 | struct | |
243 | { | |
244 | /* The referent DIE from DW_OP_GNU_implicit_pointer. */ | |
8b9737bf | 245 | sect_offset die; |
8cf6f0b1 TT |
246 | /* The byte offset into the resulting data. */ |
247 | LONGEST offset; | |
248 | } ptr; | |
cec03d70 | 249 | } v; |
87808bd6 | 250 | |
d3b1e874 | 251 | /* The length of the piece, in bits. */ |
87808bd6 | 252 | ULONGEST size; |
d3b1e874 TT |
253 | /* The piece offset, in bits. */ |
254 | ULONGEST offset; | |
4c2df51b DJ |
255 | }; |
256 | ||
b9362cc7 | 257 | struct dwarf_expr_context *new_dwarf_expr_context (void); |
4c2df51b | 258 | void free_dwarf_expr_context (struct dwarf_expr_context *ctx); |
4a227398 TT |
259 | struct cleanup * |
260 | make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx); | |
4c2df51b | 261 | |
8a9b8146 TT |
262 | void dwarf_expr_push_address (struct dwarf_expr_context *ctx, |
263 | CORE_ADDR value, | |
264 | int in_stack_memory); | |
0d45f56e | 265 | void dwarf_expr_eval (struct dwarf_expr_context *ctx, const gdb_byte *addr, |
4c2df51b | 266 | size_t len); |
8a9b8146 | 267 | struct value *dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n); |
f2c7657e | 268 | CORE_ADDR dwarf_expr_fetch_address (struct dwarf_expr_context *ctx, int n); |
44353522 | 269 | int dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context *ctx, int n); |
4c2df51b | 270 | |
3cf03773 TT |
271 | void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, |
272 | const char *); | |
273 | ||
523f3620 JK |
274 | /* Stub dwarf_expr_context_funcs implementations. */ |
275 | ||
276 | void ctx_no_get_frame_base (void *baton, const gdb_byte **start, | |
277 | size_t *length); | |
278 | CORE_ADDR ctx_no_get_frame_cfa (void *baton); | |
279 | CORE_ADDR ctx_no_get_frame_pc (void *baton); | |
280 | CORE_ADDR ctx_no_get_tls_address (void *baton, CORE_ADDR offset); | |
b64f50a1 JK |
281 | void ctx_no_dwarf_call (struct dwarf_expr_context *ctx, cu_offset die_offset); |
282 | struct type *ctx_no_get_base_type (struct dwarf_expr_context *ctx, | |
283 | cu_offset die); | |
8e3b41a9 | 284 | void ctx_no_push_dwarf_reg_entry_value (struct dwarf_expr_context *ctx, |
24c5c679 JK |
285 | enum call_site_parameter_kind kind, |
286 | union call_site_parameter_u kind_u, | |
a471c594 | 287 | int deref_size); |
3019eac3 | 288 | CORE_ADDR ctx_no_get_addr_index (void *baton, unsigned int index); |
8e3b41a9 JK |
289 | |
290 | int dwarf_block_to_dwarf_reg (const gdb_byte *buf, const gdb_byte *buf_end); | |
523f3620 | 291 | |
a471c594 JK |
292 | int dwarf_block_to_dwarf_reg_deref (const gdb_byte *buf, |
293 | const gdb_byte *buf_end, | |
294 | CORE_ADDR *deref_size_return); | |
295 | ||
e18b2753 JK |
296 | int dwarf_block_to_fb_offset (const gdb_byte *buf, const gdb_byte *buf_end, |
297 | CORE_ADDR *fb_offset_return); | |
298 | ||
299 | int dwarf_block_to_sp_offset (struct gdbarch *gdbarch, const gdb_byte *buf, | |
300 | const gdb_byte *buf_end, | |
301 | CORE_ADDR *sp_offset_return); | |
302 | ||
f664829e DE |
303 | /* Wrappers around the leb128 reader routines to simplify them for our |
304 | purposes. */ | |
305 | ||
306 | static inline const gdb_byte * | |
307 | gdb_read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
9fccedf7 | 308 | uint64_t *r) |
f664829e | 309 | { |
9fccedf7 | 310 | size_t bytes_read = read_uleb128_to_uint64 (buf, buf_end, r); |
f664829e DE |
311 | |
312 | if (bytes_read == 0) | |
313 | return NULL; | |
314 | return buf + bytes_read; | |
315 | } | |
316 | ||
317 | static inline const gdb_byte * | |
318 | gdb_read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
9fccedf7 | 319 | int64_t *r) |
f664829e | 320 | { |
9fccedf7 | 321 | size_t bytes_read = read_sleb128_to_int64 (buf, buf_end, r); |
f664829e DE |
322 | |
323 | if (bytes_read == 0) | |
324 | return NULL; | |
325 | return buf + bytes_read; | |
326 | } | |
327 | ||
328 | static inline const gdb_byte * | |
329 | gdb_skip_leb128 (const gdb_byte *buf, const gdb_byte *buf_end) | |
330 | { | |
331 | size_t bytes_read = skip_leb128 (buf, buf_end); | |
332 | ||
333 | if (bytes_read == 0) | |
334 | return NULL; | |
335 | return buf + bytes_read; | |
336 | } | |
337 | ||
338 | extern const gdb_byte *safe_read_uleb128 (const gdb_byte *buf, | |
339 | const gdb_byte *buf_end, | |
9fccedf7 | 340 | uint64_t *r); |
f664829e DE |
341 | |
342 | extern const gdb_byte *safe_read_sleb128 (const gdb_byte *buf, | |
343 | const gdb_byte *buf_end, | |
9fccedf7 | 344 | int64_t *r); |
f664829e DE |
345 | |
346 | extern const gdb_byte *safe_skip_leb128 (const gdb_byte *buf, | |
347 | const gdb_byte *buf_end); | |
348 | ||
852483bc | 349 | #endif /* dwarf2expr.h */ |