1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
/* DWARF 2 Expression Evaluator.
Copyright (C) 2001, 2002, 2003, 2005, 2007, 2008, 2009
Free Software Foundation, Inc.
Contributed by Daniel Berlin <dan@dberlin.org>.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#if !defined (DWARF2EXPR_H)
#define DWARF2EXPR_H
/* The location of a value. */
enum dwarf_value_location
{
/* The piece is in memory. */
DWARF_VALUE_MEMORY,
/* The piece is in a register. */
DWARF_VALUE_REGISTER,
/* The piece is on the stack. */
DWARF_VALUE_STACK,
/* The piece is a literal. */
DWARF_VALUE_LITERAL
};
/* The expression evaluator works with a dwarf_expr_context, describing
its current state and its callbacks. */
struct dwarf_expr_context
{
/* The stack of values, allocated with xmalloc. */
CORE_ADDR *stack;
/* The number of values currently pushed on the stack, and the
number of elements allocated to the stack. */
int stack_len, stack_allocated;
/* Target architecture to use for address operations. */
struct gdbarch *gdbarch;
/* Target address size in bytes. */
int addr_size;
/* An opaque argument provided by the caller, which will be passed
to all of the callback functions. */
void *baton;
/* Return the value of register number REGNUM. */
CORE_ADDR (*read_reg) (void *baton, int regnum);
/* Read LENGTH bytes at ADDR into BUF. */
void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length);
/* Return the location expression for the frame base attribute, in
START and LENGTH. The result must be live until the current
expression evaluation is complete. */
void (*get_frame_base) (void *baton, gdb_byte **start, size_t *length);
/* Return the CFA for the frame. */
CORE_ADDR (*get_frame_cfa) (void *baton);
/* Return the thread-local storage address for
DW_OP_GNU_push_tls_address. */
CORE_ADDR (*get_tls_address) (void *baton, CORE_ADDR offset);
#if 0
/* Not yet implemented. */
/* Return the location expression for the dwarf expression
subroutine in the die at OFFSET in the current compilation unit.
The result must be live until the current expression evaluation
is complete. */
unsigned char *(*get_subr) (void *baton, off_t offset, size_t *length);
/* Return the `object address' for DW_OP_push_object_address. */
CORE_ADDR (*get_object_address) (void *baton);
#endif
/* The current depth of dwarf expression recursion, via DW_OP_call*,
DW_OP_fbreg, DW_OP_push_object_address, etc., and the maximum
depth we'll tolerate before raising an error. */
int recursion_depth, max_recursion_depth;
/* Location of the value. */
enum dwarf_value_location location;
/* For VALUE_LITERAL, a the current literal value's length and
data. */
ULONGEST len;
gdb_byte *data;
/* Initialization status of variable: Non-zero if variable has been
initialized; zero otherwise. */
int initialized;
/* An array of pieces. PIECES points to its first element;
NUM_PIECES is its length.
Each time DW_OP_piece is executed, we add a new element to the
end of this array, recording the current top of the stack, the
current location, and the size given as the operand to
DW_OP_piece. We then pop the top value from the stack, rest the
location, and resume evaluation.
The Dwarf spec doesn't say whether DW_OP_piece pops the top value
from the stack. We do, ensuring that clients of this interface
expecting to see a value left on the top of the stack (say, code
evaluating frame base expressions or CFA's specified with
DW_CFA_def_cfa_expression) will get an error if the expression
actually marks all the values it computes as pieces.
If an expression never uses DW_OP_piece, num_pieces will be zero.
(It would be nice to present these cases as expressions yielding
a single piece, so that callers need not distinguish between the
no-DW_OP_piece and one-DW_OP_piece cases. But expressions with
no DW_OP_piece operations have no value to place in a piece's
'size' field; the size comes from the surrounding data. So the
two cases need to be handled separately.) */
int num_pieces;
struct dwarf_expr_piece *pieces;
};
/* A piece of an object, as recorded by DW_OP_piece. */
struct dwarf_expr_piece
{
enum dwarf_value_location location;
union
{
/* This piece's address or register number. */
CORE_ADDR value;
struct
{
/* A pointer to the data making up this piece, for literal
pieces. */
gdb_byte *data;
/* The length of the available data. */
ULONGEST length;
} literal;
} v;
/* The length of the piece, in bytes. */
ULONGEST size;
};
struct dwarf_expr_context *new_dwarf_expr_context (void);
void free_dwarf_expr_context (struct dwarf_expr_context *ctx);
struct cleanup *
make_cleanup_free_dwarf_expr_context (struct dwarf_expr_context *ctx);
void dwarf_expr_push (struct dwarf_expr_context *ctx, CORE_ADDR value);
void dwarf_expr_pop (struct dwarf_expr_context *ctx);
void dwarf_expr_eval (struct dwarf_expr_context *ctx, unsigned char *addr,
size_t len);
CORE_ADDR dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n);
gdb_byte *read_uleb128 (gdb_byte *buf, gdb_byte *buf_end, ULONGEST * r);
gdb_byte *read_sleb128 (gdb_byte *buf, gdb_byte *buf_end, LONGEST * r);
CORE_ADDR dwarf2_read_address (struct gdbarch *gdbarch, gdb_byte *buf,
gdb_byte *buf_end, int addr_size);
#endif /* dwarf2expr.h */
|
