Commit | Line | Data |
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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 | ||
cec03d70 TT |
26 | /* The location of a value. */ |
27 | enum dwarf_value_location | |
28 | { | |
44353522 DE |
29 | /* The piece is in memory. |
30 | The value on the dwarf stack is its address. */ | |
cec03d70 | 31 | DWARF_VALUE_MEMORY, |
44353522 DE |
32 | |
33 | /* The piece is in a register. | |
34 | The value on the dwarf stack is the register number. */ | |
cec03d70 | 35 | DWARF_VALUE_REGISTER, |
44353522 DE |
36 | |
37 | /* The piece is on the dwarf stack. */ | |
cec03d70 | 38 | DWARF_VALUE_STACK, |
44353522 | 39 | |
cec03d70 | 40 | /* The piece is a literal. */ |
cb826367 TT |
41 | DWARF_VALUE_LITERAL, |
42 | ||
43 | /* The piece was optimized out. */ | |
8cf6f0b1 TT |
44 | DWARF_VALUE_OPTIMIZED_OUT, |
45 | ||
46 | /* The piece is an implicit pointer. */ | |
47 | DWARF_VALUE_IMPLICIT_POINTER | |
cec03d70 TT |
48 | }; |
49 | ||
44353522 DE |
50 | /* The dwarf expression stack. */ |
51 | ||
52 | struct dwarf_stack_value | |
53 | { | |
8a9b8146 | 54 | struct value *value; |
44353522 DE |
55 | |
56 | /* Non-zero if the piece is in memory and is known to be | |
57 | on the program's stack. It is always ok to set this to zero. | |
58 | This is used, for example, to optimize memory access from the target. | |
59 | It can vastly speed up backtraces on long latency connections when | |
60 | "set stack-cache on". */ | |
61 | int in_stack_memory; | |
62 | }; | |
63 | ||
4c2df51b DJ |
64 | /* The expression evaluator works with a dwarf_expr_context, describing |
65 | its current state and its callbacks. */ | |
66 | struct dwarf_expr_context | |
67 | { | |
68 | /* The stack of values, allocated with xmalloc. */ | |
44353522 | 69 | struct dwarf_stack_value *stack; |
4c2df51b DJ |
70 | |
71 | /* The number of values currently pushed on the stack, and the | |
72 | number of elements allocated to the stack. */ | |
73 | int stack_len, stack_allocated; | |
74 | ||
f7fd4728 UW |
75 | /* Target architecture to use for address operations. */ |
76 | struct gdbarch *gdbarch; | |
77 | ||
ae0d2f24 UW |
78 | /* Target address size in bytes. */ |
79 | int addr_size; | |
80 | ||
ac56253d TT |
81 | /* Offset used to relocate DW_OP_addr argument. */ |
82 | CORE_ADDR offset; | |
83 | ||
4c2df51b DJ |
84 | /* An opaque argument provided by the caller, which will be passed |
85 | to all of the callback functions. */ | |
86 | void *baton; | |
87 | ||
61fbb938 DJ |
88 | /* Return the value of register number REGNUM. */ |
89 | CORE_ADDR (*read_reg) (void *baton, int regnum); | |
4c2df51b DJ |
90 | |
91 | /* Read LENGTH bytes at ADDR into BUF. */ | |
852483bc | 92 | void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length); |
4c2df51b DJ |
93 | |
94 | /* Return the location expression for the frame base attribute, in | |
95 | START and LENGTH. The result must be live until the current | |
96 | expression evaluation is complete. */ | |
0d45f56e | 97 | void (*get_frame_base) (void *baton, const gdb_byte **start, size_t *length); |
4c2df51b | 98 | |
e7802207 TT |
99 | /* Return the CFA for the frame. */ |
100 | CORE_ADDR (*get_frame_cfa) (void *baton); | |
101 | ||
8cf6f0b1 TT |
102 | /* Return the PC for the frame. */ |
103 | CORE_ADDR (*get_frame_pc) (void *baton); | |
104 | ||
4c2df51b DJ |
105 | /* Return the thread-local storage address for |
106 | DW_OP_GNU_push_tls_address. */ | |
107 | CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset); | |
108 | ||
5c631832 JK |
109 | /* Execute DW_AT_location expression for the DWARF expression subroutine in |
110 | the DIE at DIE_OFFSET in the CU from CTX. Do not touch STACK while it | |
111 | being passed to and returned from the called DWARF subroutine. */ | |
112 | void (*dwarf_call) (struct dwarf_expr_context *ctx, size_t die_offset); | |
113 | ||
8a9b8146 TT |
114 | /* Return the base type given by the indicated DIE. This can throw |
115 | an exception if the DIE is invalid or does not represent a base | |
116 | type. If can also be NULL in the special case where the | |
117 | callbacks are not performing evaluation, and thus it is | |
118 | meaningful to substitute a stub type of the correct size. */ | |
119 | struct type *(*get_base_type) (struct dwarf_expr_context *ctx, size_t die); | |
120 | ||
4c2df51b DJ |
121 | #if 0 |
122 | /* Not yet implemented. */ | |
123 | ||
4c2df51b DJ |
124 | /* Return the `object address' for DW_OP_push_object_address. */ |
125 | CORE_ADDR (*get_object_address) (void *baton); | |
126 | #endif | |
127 | ||
128 | /* The current depth of dwarf expression recursion, via DW_OP_call*, | |
129 | DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum | |
130 | depth we'll tolerate before raising an error. */ | |
131 | int recursion_depth, max_recursion_depth; | |
132 | ||
cec03d70 TT |
133 | /* Location of the value. */ |
134 | enum dwarf_value_location location; | |
135 | ||
766062f6 | 136 | /* For DWARF_VALUE_LITERAL, the current literal value's length and |
8cf6f0b1 TT |
137 | data. For DWARF_VALUE_IMPLICIT_POINTER, LEN is the offset of the |
138 | target DIE. */ | |
cec03d70 | 139 | ULONGEST len; |
0d45f56e | 140 | const gdb_byte *data; |
87808bd6 | 141 | |
42be36b3 CT |
142 | /* Initialization status of variable: Non-zero if variable has been |
143 | initialized; zero otherwise. */ | |
144 | int initialized; | |
145 | ||
87808bd6 JB |
146 | /* An array of pieces. PIECES points to its first element; |
147 | NUM_PIECES is its length. | |
148 | ||
149 | Each time DW_OP_piece is executed, we add a new element to the | |
150 | end of this array, recording the current top of the stack, the | |
cec03d70 | 151 | current location, and the size given as the operand to |
44353522 | 152 | DW_OP_piece. We then pop the top value from the stack, reset the |
cec03d70 | 153 | location, and resume evaluation. |
87808bd6 JB |
154 | |
155 | The Dwarf spec doesn't say whether DW_OP_piece pops the top value | |
156 | from the stack. We do, ensuring that clients of this interface | |
157 | expecting to see a value left on the top of the stack (say, code | |
158 | evaluating frame base expressions or CFA's specified with | |
159 | DW_CFA_def_cfa_expression) will get an error if the expression | |
160 | actually marks all the values it computes as pieces. | |
161 | ||
162 | If an expression never uses DW_OP_piece, num_pieces will be zero. | |
163 | (It would be nice to present these cases as expressions yielding | |
cec03d70 TT |
164 | a single piece, so that callers need not distinguish between the |
165 | no-DW_OP_piece and one-DW_OP_piece cases. But expressions with | |
166 | no DW_OP_piece operations have no value to place in a piece's | |
167 | 'size' field; the size comes from the surrounding data. So the | |
168 | two cases need to be handled separately.) */ | |
87808bd6 JB |
169 | int num_pieces; |
170 | struct dwarf_expr_piece *pieces; | |
171 | }; | |
172 | ||
173 | ||
d3b1e874 | 174 | /* A piece of an object, as recorded by DW_OP_piece or DW_OP_bit_piece. */ |
87808bd6 JB |
175 | struct dwarf_expr_piece |
176 | { | |
cec03d70 TT |
177 | enum dwarf_value_location location; |
178 | ||
179 | union | |
180 | { | |
44353522 DE |
181 | struct |
182 | { | |
f2c7657e UW |
183 | /* This piece's address, for DWARF_VALUE_MEMORY pieces. */ |
184 | CORE_ADDR addr; | |
44353522 DE |
185 | /* Non-zero if the piece is known to be in memory and on |
186 | the program's stack. */ | |
187 | int in_stack_memory; | |
f2c7657e UW |
188 | } mem; |
189 | ||
8a9b8146 TT |
190 | /* The piece's register number, for DWARF_VALUE_REGISTER pieces. */ |
191 | int regno; | |
192 | ||
193 | /* The piece's literal value, for DWARF_VALUE_STACK pieces. */ | |
194 | struct value *value; | |
cec03d70 TT |
195 | |
196 | struct | |
197 | { | |
f2c7657e UW |
198 | /* A pointer to the data making up this piece, |
199 | for DWARF_VALUE_LITERAL pieces. */ | |
0d45f56e | 200 | const gdb_byte *data; |
cec03d70 TT |
201 | /* The length of the available data. */ |
202 | ULONGEST length; | |
203 | } literal; | |
8cf6f0b1 TT |
204 | |
205 | /* Used for DWARF_VALUE_IMPLICIT_POINTER. */ | |
206 | struct | |
207 | { | |
208 | /* The referent DIE from DW_OP_GNU_implicit_pointer. */ | |
209 | ULONGEST die; | |
210 | /* The byte offset into the resulting data. */ | |
211 | LONGEST offset; | |
212 | } ptr; | |
cec03d70 | 213 | } v; |
87808bd6 | 214 | |
d3b1e874 | 215 | /* The length of the piece, in bits. */ |
87808bd6 | 216 | ULONGEST size; |
d3b1e874 TT |
217 | /* The piece offset, in bits. */ |
218 | ULONGEST offset; | |
4c2df51b DJ |
219 | }; |
220 | ||
b9362cc7 | 221 | struct dwarf_expr_context *new_dwarf_expr_context (void); |
4c2df51b | 222 | void free_dwarf_expr_context (struct dwarf_expr_context *ctx); |
4a227398 TT |
223 | struct cleanup * |
224 | make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx); | |
4c2df51b | 225 | |
8a9b8146 TT |
226 | void dwarf_expr_push_address (struct dwarf_expr_context *ctx, |
227 | CORE_ADDR value, | |
228 | int in_stack_memory); | |
0d45f56e | 229 | void dwarf_expr_eval (struct dwarf_expr_context *ctx, const gdb_byte *addr, |
4c2df51b | 230 | size_t len); |
8a9b8146 | 231 | struct value *dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n); |
f2c7657e | 232 | CORE_ADDR dwarf_expr_fetch_address (struct dwarf_expr_context *ctx, int n); |
44353522 | 233 | int dwarf_expr_fetch_in_stack_memory (struct dwarf_expr_context *ctx, int n); |
4c2df51b | 234 | |
a55cc764 | 235 | |
0d45f56e TT |
236 | const gdb_byte *read_uleb128 (const gdb_byte *buf, const gdb_byte *buf_end, |
237 | ULONGEST * r); | |
238 | const gdb_byte *read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end, | |
239 | LONGEST * r); | |
a55cc764 | 240 | |
b1bfef65 | 241 | const char *dwarf_stack_op_name (unsigned int); |
9eae7c52 | 242 | |
3cf03773 TT |
243 | void dwarf_expr_require_composition (const gdb_byte *, const gdb_byte *, |
244 | const char *); | |
245 | ||
852483bc | 246 | #endif /* dwarf2expr.h */ |