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852483bc MK |
1 | /* DWARF 2 Expression Evaluator. |
2 | ||
7b6bb8da | 3 | Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009, 2010, 2011 |
9b254dd1 | 4 | Free Software Foundation, 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 | ||
9e8b7a03 JK |
26 | struct dwarf_expr_context; |
27 | ||
28 | /* Virtual method table for struct dwarf_expr_context below. */ | |
29 | ||
30 | struct dwarf_expr_context_funcs | |
31 | { | |
32 | /* Return the value of register number REGNUM. */ | |
33 | CORE_ADDR (*read_reg) (void *baton, int regnum); | |
34 | ||
35 | /* Read LENGTH bytes at ADDR into BUF. */ | |
36 | void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length); | |
37 | ||
38 | /* Return the location expression for the frame base attribute, in | |
39 | START and LENGTH. The result must be live until the current | |
40 | expression evaluation is complete. */ | |
41 | void (*get_frame_base) (void *baton, const gdb_byte **start, size_t *length); | |
42 | ||
43 | /* Return the CFA for the frame. */ | |
44 | CORE_ADDR (*get_frame_cfa) (void *baton); | |
45 | ||
46 | /* Return the PC for the frame. */ | |
47 | CORE_ADDR (*get_frame_pc) (void *baton); | |
48 | ||
49 | /* Return the thread-local storage address for | |
50 | DW_OP_GNU_push_tls_address. */ | |
51 | CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset); | |
52 | ||
53 | /* Execute DW_AT_location expression for the DWARF expression subroutine in | |
54 | the DIE at DIE_OFFSET in the CU from CTX. Do not touch STACK while it | |
55 | being passed to and returned from the called DWARF subroutine. */ | |
56 | void (*dwarf_call) (struct dwarf_expr_context *ctx, size_t die_offset); | |
57 | ||
58 | /* Return the base type given by the indicated DIE. This can throw | |
59 | an exception if the DIE is invalid or does not represent a base | |
60 | type. If can also be NULL in the special case where the | |
61 | callbacks are not performing evaluation, and thus it is | |
62 | meaningful to substitute a stub type of the correct size. */ | |
63 | struct type *(*get_base_type) (struct dwarf_expr_context *ctx, size_t die); | |
64 | ||
65 | #if 0 | |
66 | /* Not yet implemented. */ | |
67 | ||
68 | /* Return the `object address' for DW_OP_push_object_address. */ | |
69 | CORE_ADDR (*get_object_address) (void *baton); | |
70 | #endif | |
71 | }; | |
72 | ||
cec03d70 TT |
73 | /* The location of a value. */ |
74 | enum dwarf_value_location | |
75 | { | |
44353522 DE |
76 | /* The piece is in memory. |
77 | The value on the dwarf stack is its address. */ | |
cec03d70 | 78 | DWARF_VALUE_MEMORY, |
44353522 DE |
79 | |
80 | /* The piece is in a register. | |
81 | The value on the dwarf stack is the register number. */ | |
cec03d70 | 82 | DWARF_VALUE_REGISTER, |
44353522 DE |
83 | |
84 | /* The piece is on the dwarf stack. */ | |
cec03d70 | 85 | DWARF_VALUE_STACK, |
44353522 | 86 | |
cec03d70 | 87 | /* The piece is a literal. */ |
cb826367 TT |
88 | DWARF_VALUE_LITERAL, |
89 | ||
90 | /* The piece was optimized out. */ | |
8cf6f0b1 TT |
91 | DWARF_VALUE_OPTIMIZED_OUT, |
92 | ||
93 | /* The piece is an implicit pointer. */ | |
94 | DWARF_VALUE_IMPLICIT_POINTER | |
cec03d70 TT |
95 | }; |
96 | ||
44353522 DE |
97 | /* The dwarf expression stack. */ |
98 | ||
99 | struct dwarf_stack_value | |
100 | { | |
8a9b8146 | 101 | struct value *value; |
44353522 DE |
102 | |
103 | /* Non-zero if the piece is in memory and is known to be | |
104 | on the program's stack. It is always ok to set this to zero. | |
105 | This is used, for example, to optimize memory access from the target. | |
106 | It can vastly speed up backtraces on long latency connections when | |
107 | "set stack-cache on". */ | |
108 | int in_stack_memory; | |
109 | }; | |
110 | ||
4c2df51b DJ |
111 | /* The expression evaluator works with a dwarf_expr_context, describing |
112 | its current state and its callbacks. */ | |
113 | struct dwarf_expr_context | |
114 | { | |
115 | /* The stack of values, allocated with xmalloc. */ | |
44353522 | 116 | struct dwarf_stack_value *stack; |
4c2df51b DJ |
117 | |
118 | /* The number of values currently pushed on the stack, and the | |
119 | number of elements allocated to the stack. */ | |
120 | int stack_len, stack_allocated; | |
121 | ||
f7fd4728 UW |
122 | /* Target architecture to use for address operations. */ |
123 | struct gdbarch *gdbarch; | |
124 | ||
ae0d2f24 UW |
125 | /* Target address size in bytes. */ |
126 | int addr_size; | |
127 | ||
181cebd4 JK |
128 | /* DW_FORM_ref_addr size in bytes. If -1 DWARF is executed from a frame |
129 | context and operations depending on DW_FORM_ref_addr are not allowed. */ | |
130 | int ref_addr_size; | |
131 | ||
ac56253d TT |
132 | /* Offset used to relocate DW_OP_addr argument. */ |
133 | CORE_ADDR offset; | |
134 | ||
4c2df51b DJ |
135 | /* An opaque argument provided by the caller, which will be passed |
136 | to all of the callback functions. */ | |
137 | void *baton; | |
138 | ||
9e8b7a03 JK |
139 | /* Callback functions. */ |
140 | const struct dwarf_expr_context_funcs *funcs; | |
4c2df51b DJ |
141 | |
142 | /* The current depth of dwarf expression recursion, via DW_OP_call*, | |
143 | DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum | |
144 | depth we'll tolerate before raising an error. */ | |
145 | int recursion_depth, max_recursion_depth; | |
146 | ||
cec03d70 TT |
147 | /* Location of the value. */ |
148 | enum dwarf_value_location location; | |
149 | ||
766062f6 | 150 | /* For DWARF_VALUE_LITERAL, the current literal value's length and |
8cf6f0b1 TT |
151 | data. For DWARF_VALUE_IMPLICIT_POINTER, LEN is the offset of the |
152 | target DIE. */ | |
cec03d70 | 153 | ULONGEST len; |
0d45f56e | 154 | const gdb_byte *data; |
87808bd6 | 155 | |
42be36b3 CT |
156 | /* Initialization status of variable: Non-zero if variable has been |
157 | initialized; zero otherwise. */ | |
158 | int initialized; | |
159 | ||
87808bd6 JB |
160 | /* An array of pieces. PIECES points to its first element; |
161 | NUM_PIECES is its length. | |
162 | ||
163 | Each time DW_OP_piece is executed, we add a new element to the | |
164 | end of this array, recording the current top of the stack, the | |
cec03d70 | 165 | current location, and the size given as the operand to |
44353522 | 166 | DW_OP_piece. We then pop the top value from the stack, reset the |
cec03d70 | 167 | location, and resume evaluation. |
87808bd6 JB |
168 | |
169 | The Dwarf spec doesn't say whether DW_OP_piece pops the top value | |
170 | from the stack. We do, ensuring that clients of this interface | |
171 | expecting to see a value left on the top of the stack (say, code | |
172 | evaluating frame base expressions or CFA's specified with | |
173 | DW_CFA_def_cfa_expression) will get an error if the expression | |
174 | actually marks all the values it computes as pieces. | |
175 | ||
176 | If an expression never uses DW_OP_piece, num_pieces will be zero. | |
177 | (It would be nice to present these cases as expressions yielding | |
cec03d70 TT |
178 | a single piece, so that callers need not distinguish between the |
179 | no-DW_OP_piece and one-DW_OP_piece cases. But expressions with | |
180 | no DW_OP_piece operations have no value to place in a piece's | |
181 | 'size' field; the size comes from the surrounding data. So the | |
182 | two cases need to be handled separately.) */ | |
87808bd6 JB |
183 | int num_pieces; |
184 | struct dwarf_expr_piece *pieces; | |
185 | }; | |
186 | ||
187 | ||
d3b1e874 | 188 | /* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */ |
87808bd6 JB |
189 | struct dwarf_expr_piece |
190 | { | |
cec03d70 TT |
191 | enum dwarf_value_location location; |
192 | ||
193 | union | |
194 | { | |
44353522 DE |
195 | struct |
196 | { | |
f2c7657e UW |
197 | /* This piece's address, for DWARF_VALUE_MEMORY pieces. */ |
198 | CORE_ADDR addr; | |
44353522 DE |
199 | /* Non-zero if the piece is known to be in memory and on |
200 | the program's stack. */ | |
201 | int in_stack_memory; | |
f2c7657e UW |
202 | } mem; |
203 | ||
8a9b8146 TT |
204 | /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */ |
205 | int regno; | |
206 | ||
207 | /* The piece's literal value, for DWARF_VALUE_STACK pieces. */ | |
208 | struct value *value; | |
cec03d70 TT |
209 | |
210 | struct | |
211 | { | |
f2c7657e UW |
212 | /* A pointer to the data making up this piece, |
213 | for DWARF_VALUE_LITERAL pieces. */ | |
0d45f56e | 214 | const gdb_byte *data; |
cec03d70 TT |
215 | /* The length of the available data. */ |
216 | ULONGEST length; | |
217 | } literal; | |
8cf6f0b1 TT |
218 | |
219 | /* Used for DWARF_VALUE_IMPLICIT_POINTER. */ | |
220 | struct | |
221 | { | |
222 | /* The referent DIE from DW_OP_GNU_implicit_pointer. */ | |
223 | ULONGEST die; | |
224 | /* The byte offset into the resulting data. */ | |
225 | LONGEST offset; | |
226 | } ptr; | |
cec03d70 | 227 | } v; |
87808bd6 | 228 | |
d3b1e874 | 229 | /* The length of the piece, in bits. */ |
87808bd6 | 230 | ULONGEST size; |
d3b1e874 TT |
231 | /* The piece offset, in bits. */ |
232 | ULONGEST offset; | |
4c2df51b DJ |
233 | }; |
234 | ||
b9362cc7 | 235 | struct dwarf_expr_context *new_dwarf_expr_context (void); |
4c2df51b | 236 | void free_dwarf_expr_context (struct dwarf_expr_context *ctx); |
4a227398 TT |
237 | struct cleanup * |
238 | make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx); | |
4c2df51b | 239 | |
8a9b8146 TT |
240 | void dwarf_expr_push_address (struct dwarf_expr_context *ctx, |
241 | CORE_ADDR value, | |
242 | int in_stack_memory); | |
0d45f56e | 243 | void dwarf_expr_eval (struct dwarf_expr_context *ctx, const gdb_byte *addr, |
4c2df51b | 244 | size_t len); |
8a9b8146 | 245 | struct value *dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n); |
f2c7657e | 246 | CORE_ADDR dwarf_expr_fetch_address (struct dwarf_expr_context *ctx, int n); |
44353522 | 247 | int dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context *ctx, int n); |
4c2df51b | 248 | |
a55cc764 | 249 | |
0d45f56e TT |
250 | const gdb_byte *read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, |
251 | ULONGEST * r); | |
252 | const gdb_byte *read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
253 | LONGEST * r); | |
a55cc764 | 254 | |
b1bfef65 | 255 | const char *dwarf_stack_op_name (unsigned int); |
9eae7c52 | 256 | |
3cf03773 TT |
257 | void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, |
258 | const char *); | |
259 | ||
523f3620 JK |
260 | /* Stub dwarf_expr_context_funcs implementations. */ |
261 | ||
3c6e0cb3 | 262 | CORE_ADDR ctx_no_read_reg (void *baton, int regnum); |
523f3620 JK |
263 | void ctx_no_get_frame_base (void *baton, const gdb_byte **start, |
264 | size_t *length); | |
265 | CORE_ADDR ctx_no_get_frame_cfa (void *baton); | |
266 | CORE_ADDR ctx_no_get_frame_pc (void *baton); | |
267 | CORE_ADDR ctx_no_get_tls_address (void *baton, CORE_ADDR offset); | |
268 | void ctx_no_dwarf_call (struct dwarf_expr_context *ctx, size_t die_offset); | |
269 | struct type *ctx_no_get_base_type (struct dwarf_expr_context *ctx, size_t die); | |
270 | ||
852483bc | 271 | #endif /* dwarf2expr.h */ |