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852483bc MK |
1 | /* DWARF 2 Expression Evaluator. |
2 | ||
0fb0cc75 | 3 | Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009 |
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 | { | |
29 | /* The piece is in memory. */ | |
30 | DWARF_VALUE_MEMORY, | |
31 | /* The piece is in a register. */ | |
32 | DWARF_VALUE_REGISTER, | |
33 | /* The piece is on the stack. */ | |
34 | DWARF_VALUE_STACK, | |
35 | /* The piece is a literal. */ | |
36 | DWARF_VALUE_LITERAL | |
37 | }; | |
38 | ||
4c2df51b DJ |
39 | /* The expression evaluator works with a dwarf_expr_context, describing |
40 | its current state and its callbacks. */ | |
41 | struct dwarf_expr_context | |
42 | { | |
43 | /* The stack of values, allocated with xmalloc. */ | |
44 | CORE_ADDR *stack; | |
45 | ||
46 | /* The number of values currently pushed on the stack, and the | |
47 | number of elements allocated to the stack. */ | |
48 | int stack_len, stack_allocated; | |
49 | ||
f7fd4728 UW |
50 | /* Target architecture to use for address operations. */ |
51 | struct gdbarch *gdbarch; | |
52 | ||
ae0d2f24 UW |
53 | /* Target address size in bytes. */ |
54 | int addr_size; | |
55 | ||
4c2df51b DJ |
56 | /* An opaque argument provided by the caller, which will be passed |
57 | to all of the callback functions. */ | |
58 | void *baton; | |
59 | ||
61fbb938 DJ |
60 | /* Return the value of register number REGNUM. */ |
61 | CORE_ADDR (*read_reg) (void *baton, int regnum); | |
4c2df51b DJ |
62 | |
63 | /* Read LENGTH bytes at ADDR into BUF. */ | |
852483bc | 64 | void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length); |
4c2df51b DJ |
65 | |
66 | /* Return the location expression for the frame base attribute, in | |
67 | START and LENGTH. The result must be live until the current | |
68 | expression evaluation is complete. */ | |
852483bc | 69 | void (*get_frame_base) (void *baton, gdb_byte **start, size_t *length); |
4c2df51b | 70 | |
e7802207 TT |
71 | /* Return the CFA for the frame. */ |
72 | CORE_ADDR (*get_frame_cfa) (void *baton); | |
73 | ||
4c2df51b DJ |
74 | /* Return the thread-local storage address for |
75 | DW_OP_GNU_push_tls_address. */ | |
76 | CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset); | |
77 | ||
78 | #if 0 | |
79 | /* Not yet implemented. */ | |
80 | ||
81 | /* Return the location expression for the dwarf expression | |
82 | subroutine in the die at OFFSET in the current compilation unit. | |
83 | The result must be live until the current expression evaluation | |
84 | is complete. */ | |
85 | unsigned char *(*get_subr) (void *baton, off_t offset, size_t *length); | |
86 | ||
87 | /* Return the `object address' for DW_OP_push_object_address. */ | |
88 | CORE_ADDR (*get_object_address) (void *baton); | |
89 | #endif | |
90 | ||
91 | /* The current depth of dwarf expression recursion, via DW_OP_call*, | |
92 | DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum | |
93 | depth we'll tolerate before raising an error. */ | |
94 | int recursion_depth, max_recursion_depth; | |
95 | ||
cec03d70 TT |
96 | /* Location of the value. */ |
97 | enum dwarf_value_location location; | |
98 | ||
99 | /* For VALUE_LITERAL, a the current literal value's length and | |
100 | data. */ | |
101 | ULONGEST len; | |
102 | gdb_byte *data; | |
87808bd6 | 103 | |
42be36b3 CT |
104 | /* Initialization status of variable: Non-zero if variable has been |
105 | initialized; zero otherwise. */ | |
106 | int initialized; | |
107 | ||
87808bd6 JB |
108 | /* An array of pieces. PIECES points to its first element; |
109 | NUM_PIECES is its length. | |
110 | ||
111 | Each time DW_OP_piece is executed, we add a new element to the | |
112 | end of this array, recording the current top of the stack, the | |
cec03d70 TT |
113 | current location, and the size given as the operand to |
114 | DW_OP_piece. We then pop the top value from the stack, rest the | |
115 | location, and resume evaluation. | |
87808bd6 JB |
116 | |
117 | The Dwarf spec doesn't say whether DW_OP_piece pops the top value | |
118 | from the stack. We do, ensuring that clients of this interface | |
119 | expecting to see a value left on the top of the stack (say, code | |
120 | evaluating frame base expressions or CFA's specified with | |
121 | DW_CFA_def_cfa_expression) will get an error if the expression | |
122 | actually marks all the values it computes as pieces. | |
123 | ||
124 | If an expression never uses DW_OP_piece, num_pieces will be zero. | |
125 | (It would be nice to present these cases as expressions yielding | |
cec03d70 TT |
126 | a single piece, so that callers need not distinguish between the |
127 | no-DW_OP_piece and one-DW_OP_piece cases. But expressions with | |
128 | no DW_OP_piece operations have no value to place in a piece's | |
129 | 'size' field; the size comes from the surrounding data. So the | |
130 | two cases need to be handled separately.) */ | |
87808bd6 JB |
131 | int num_pieces; |
132 | struct dwarf_expr_piece *pieces; | |
133 | }; | |
134 | ||
135 | ||
136 | /* A piece of an object, as recorded by DW_OP_piece. */ | |
137 | struct dwarf_expr_piece | |
138 | { | |
cec03d70 TT |
139 | enum dwarf_value_location location; |
140 | ||
141 | union | |
142 | { | |
143 | /* This piece's address or register number. */ | |
144 | CORE_ADDR value; | |
145 | ||
146 | struct | |
147 | { | |
148 | /* A pointer to the data making up this piece, for literal | |
149 | pieces. */ | |
150 | gdb_byte *data; | |
151 | /* The length of the available data. */ | |
152 | ULONGEST length; | |
153 | } literal; | |
154 | } v; | |
87808bd6 JB |
155 | |
156 | /* The length of the piece, in bytes. */ | |
157 | ULONGEST size; | |
4c2df51b DJ |
158 | }; |
159 | ||
b9362cc7 | 160 | struct dwarf_expr_context *new_dwarf_expr_context (void); |
4c2df51b | 161 | void free_dwarf_expr_context (struct dwarf_expr_context *ctx); |
4a227398 TT |
162 | struct cleanup * |
163 | make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx); | |
4c2df51b DJ |
164 | |
165 | void dwarf_expr_push (struct dwarf_expr_context *ctx, CORE_ADDR value); | |
166 | void dwarf_expr_pop (struct dwarf_expr_context *ctx); | |
167 | void dwarf_expr_eval (struct dwarf_expr_context *ctx, unsigned char *addr, | |
168 | size_t len); | |
169 | CORE_ADDR dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n); | |
170 | ||
a55cc764 | 171 | |
852483bc MK |
172 | gdb_byte *read_uleb128 (gdb_byte *buf, gdb_byte *buf_end, ULONGEST * r); |
173 | gdb_byte *read_sleb128 (gdb_byte *buf, gdb_byte *buf_end, LONGEST * r); | |
f7fd4728 UW |
174 | CORE_ADDR dwarf2_read_address (struct gdbarch *gdbarch, gdb_byte *buf, |
175 | gdb_byte *buf_end, int addr_size); | |
a55cc764 | 176 | |
852483bc | 177 | #endif /* dwarf2expr.h */ |