1 /* libunwind - a platform-independent unwind library
2 Copyright (C) 2002-2004 Hewlett-Packard Co
3 Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
5 This file is part of libunwind.
7 Permission is hereby granted, free of charge, to any person obtaining
8 a copy of this software and associated documentation files (the
9 "Software"), to deal in the Software without restriction, including
10 without limitation the rights to use, copy, modify, merge, publish,
11 distribute, sublicense, and/or sell copies of the Software, and to
12 permit persons to whom the Software is furnished to do so, subject to
13 the following conditions:
15 The above copyright notice and this permission notice shall be
16 included in all copies or substantial portions of the Software.
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
26 /* This file defines the runtime-support routines for dynamically
27 generated code. Even though it is implemented as part of libunwind,
28 it is logically separate from the interface to perform the actual
29 unwinding. In particular, this interface is always used in the
30 context of the unwind target, whereas the rest of the unwind API is
31 used in context of the process that is doing the unwind (which may be
32 a debugger running on another machine, for example).
34 Note that the data-structures declared here server a dual purpose:
35 when a program registers a dynamically generated procedure, it uses
36 these structures directly. On the other hand, with remote-unwinding,
37 the data-structures are read from the remote process's memory and
38 translated into internalized versions. To facilitate remote-access,
39 the following rules should be followed in declaring these structures:
41 (1) Declare a member as a pointer only if the the information the
42 member points to needs to be internalized as well (e.g., a
43 string representing a procedure name should be declared as
44 "const char *", but the instruction pointer should be declared
47 (2) Provide sufficient padding to ensure that no implicit padding
48 will be needed on any of the supported target architectures. For
49 the time being, padding data structures with the assumption that
50 sizeof (unw_word_t) == 8 should be sufficient. (Note: it's not
51 impossible to internalize structures with internal padding, but
52 it does make the process a bit harder).
54 (3) Don't declare members that contain bitfields or floating-point
57 (4) Don't declare members with enumeration types. Declare them as
62 UNW_DYN_STOP = 0, /* end-of-unwind-info marker */
63 UNW_DYN_SAVE_REG, /* save register to another register */
64 UNW_DYN_SPILL_FP_REL, /* frame-pointer-relative register spill */
65 UNW_DYN_SPILL_SP_REL, /* stack-pointer-relative register spill */
66 UNW_DYN_ADD, /* add constant value to a register */
67 UNW_DYN_POP_FRAMES, /* drop one or more stack frames */
68 UNW_DYN_LABEL_STATE, /* name the current state */
69 UNW_DYN_COPY_STATE, /* set the region's entry-state */
70 UNW_DYN_ALIAS /* get unwind info from an alias */
76 UNW_INFO_FORMAT_DYNAMIC, /* unw_dyn_proc_info_t */
77 UNW_INFO_FORMAT_TABLE, /* unw_dyn_table_t */
78 UNW_INFO_FORMAT_REMOTE_TABLE, /* unw_dyn_remote_table_t */
79 UNW_INFO_FORMAT_ARM_EXIDX, /* ARM specific unwind info */
80 UNW_INFO_FORMAT_IP_OFFSET, /* Like UNW_INFO_FORMAT_REMOTE_TABLE, but
81 table entries are considered
82 relative to di->start_ip, rather
85 unw_dyn_info_format_t;
87 typedef struct unw_dyn_op
89 int8_t tag; /* what operation? */
90 int8_t qp; /* qualifying predicate register */
91 int16_t reg; /* what register */
92 int32_t when; /* when does it take effect? */
93 unw_word_t val; /* auxiliary value */
97 typedef struct unw_dyn_region_info
99 struct unw_dyn_region_info *next; /* linked list of regions */
100 int32_t insn_count; /* region length (# of instructions) */
101 uint32_t op_count; /* length of op-array */
102 unw_dyn_op_t op[1]; /* variable-length op-array */
104 unw_dyn_region_info_t;
106 typedef struct unw_dyn_proc_info
108 unw_word_t name_ptr; /* address of human-readable procedure name */
109 unw_word_t handler; /* address of personality routine */
112 unw_dyn_region_info_t *regions;
116 typedef struct unw_dyn_table_info
118 unw_word_t name_ptr; /* addr. of table name (e.g., library name) */
119 unw_word_t segbase; /* segment base */
120 unw_word_t table_len; /* must be a multiple of sizeof(unw_word_t)! */
121 unw_word_t *table_data;
123 unw_dyn_table_info_t;
125 typedef struct unw_dyn_remote_table_info
127 unw_word_t name_ptr; /* addr. of table name (e.g., library name) */
128 unw_word_t segbase; /* segment base */
129 unw_word_t table_len; /* must be a multiple of sizeof(unw_word_t)! */
130 unw_word_t table_data;
132 unw_dyn_remote_table_info_t;
134 typedef struct unw_dyn_info
136 /* doubly-linked list of dyn-info structures: */
137 struct unw_dyn_info *next;
138 struct unw_dyn_info *prev;
139 unw_word_t start_ip; /* first IP covered by this entry */
140 unw_word_t end_ip; /* first IP NOT covered by this entry */
141 unw_word_t gp; /* global-pointer in effect for this entry */
142 int32_t format; /* real type: unw_dyn_info_format_t */
146 unw_dyn_proc_info_t pi;
147 unw_dyn_table_info_t ti;
148 unw_dyn_remote_table_info_t rti;
154 typedef struct unw_dyn_info_list
158 unw_dyn_info_t *first;
162 /* Return the size (in bytes) of an unw_dyn_region_info_t structure that can
163 hold OP_COUNT ops. */
164 #define _U_dyn_region_info_size(op_count) \
165 ((char *) (((unw_dyn_region_info_t *) NULL)->op + (op_count)) \
168 /* Register the unwind info for a single procedure.
169 This routine is NOT signal-safe. */
170 extern void _U_dyn_register (unw_dyn_info_t *);
172 /* Cancel the unwind info for a single procedure.
173 This routine is NOT signal-safe. */
174 extern void _U_dyn_cancel (unw_dyn_info_t *);
177 /* Convenience routines. */
179 #define _U_dyn_op(_tag, _qp, _when, _reg, _val) \
180 ((unw_dyn_op_t) { (_tag), (_qp), (_reg), (_when), (_val) })
182 #define _U_dyn_op_save_reg(op, qp, when, reg, dst) \
183 (*(op) = _U_dyn_op (UNW_DYN_SAVE_REG, (qp), (when), (reg), (dst)))
185 #define _U_dyn_op_spill_fp_rel(op, qp, when, reg, offset) \
186 (*(op) = _U_dyn_op (UNW_DYN_SPILL_FP_REL, (qp), (when), (reg), \
189 #define _U_dyn_op_spill_sp_rel(op, qp, when, reg, offset) \
190 (*(op) = _U_dyn_op (UNW_DYN_SPILL_SP_REL, (qp), (when), (reg), \
193 #define _U_dyn_op_add(op, qp, when, reg, value) \
194 (*(op) = _U_dyn_op (UNW_DYN_ADD, (qp), (when), (reg), (value)))
196 #define _U_dyn_op_pop_frames(op, qp, when, num_frames) \
197 (*(op) = _U_dyn_op (UNW_DYN_POP_FRAMES, (qp), (when), 0, (num_frames)))
199 #define _U_dyn_op_label_state(op, label) \
200 (*(op) = _U_dyn_op (UNW_DYN_LABEL_STATE, _U_QP_TRUE, -1, 0, (label)))
202 #define _U_dyn_op_copy_state(op, label) \
203 (*(op) = _U_dyn_op (UNW_DYN_COPY_STATE, _U_QP_TRUE, -1, 0, (label)))
205 #define _U_dyn_op_alias(op, qp, when, addr) \
206 (*(op) = _U_dyn_op (UNW_DYN_ALIAS, (qp), (when), 0, (addr)))
208 #define _U_dyn_op_stop(op) \
209 (*(op) = _U_dyn_op (UNW_DYN_STOP, _U_QP_TRUE, -1, 0, 0))
211 /* The target-dependent qualifying predicate which is always TRUE. On
212 IA-64, that's p0 (0), on non-predicated architectures, the value is
214 #define _U_QP_TRUE _U_TDEP_QP_TRUE