| 1 | /* Definitions for frame unwinder, for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010, 2011 |
| 4 | Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "frame.h" |
| 23 | #include "frame-unwind.h" |
| 24 | #include "dummy-frame.h" |
| 25 | #include "inline-frame.h" |
| 26 | #include "value.h" |
| 27 | #include "regcache.h" |
| 28 | #include "exceptions.h" |
| 29 | #include "gdb_assert.h" |
| 30 | #include "gdb_obstack.h" |
| 31 | |
| 32 | static struct gdbarch_data *frame_unwind_data; |
| 33 | |
| 34 | struct frame_unwind_table_entry |
| 35 | { |
| 36 | const struct frame_unwind *unwinder; |
| 37 | struct frame_unwind_table_entry *next; |
| 38 | }; |
| 39 | |
| 40 | struct frame_unwind_table |
| 41 | { |
| 42 | struct frame_unwind_table_entry *list; |
| 43 | /* The head of the OSABI part of the search list. */ |
| 44 | struct frame_unwind_table_entry **osabi_head; |
| 45 | }; |
| 46 | |
| 47 | static void * |
| 48 | frame_unwind_init (struct obstack *obstack) |
| 49 | { |
| 50 | struct frame_unwind_table *table |
| 51 | = OBSTACK_ZALLOC (obstack, struct frame_unwind_table); |
| 52 | |
| 53 | /* Start the table out with a few default sniffers. OSABI code |
| 54 | can't override this. */ |
| 55 | table->list = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry); |
| 56 | table->list->unwinder = &dummy_frame_unwind; |
| 57 | table->list->next = OBSTACK_ZALLOC (obstack, |
| 58 | struct frame_unwind_table_entry); |
| 59 | table->list->next->unwinder = &inline_frame_unwind; |
| 60 | /* The insertion point for OSABI sniffers. */ |
| 61 | table->osabi_head = &table->list->next->next; |
| 62 | return table; |
| 63 | } |
| 64 | |
| 65 | void |
| 66 | frame_unwind_prepend_unwinder (struct gdbarch *gdbarch, |
| 67 | const struct frame_unwind *unwinder) |
| 68 | { |
| 69 | struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data); |
| 70 | struct frame_unwind_table_entry *entry; |
| 71 | |
| 72 | /* Insert the new entry at the start of the list. */ |
| 73 | entry = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry); |
| 74 | entry->unwinder = unwinder; |
| 75 | entry->next = (*table->osabi_head); |
| 76 | (*table->osabi_head) = entry; |
| 77 | } |
| 78 | |
| 79 | void |
| 80 | frame_unwind_append_unwinder (struct gdbarch *gdbarch, |
| 81 | const struct frame_unwind *unwinder) |
| 82 | { |
| 83 | struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data); |
| 84 | struct frame_unwind_table_entry **ip; |
| 85 | |
| 86 | /* Find the end of the list and insert the new entry there. */ |
| 87 | for (ip = table->osabi_head; (*ip) != NULL; ip = &(*ip)->next); |
| 88 | (*ip) = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry); |
| 89 | (*ip)->unwinder = unwinder; |
| 90 | } |
| 91 | |
| 92 | /* Iterate through sniffers for THIS_FRAME frame until one returns with an |
| 93 | unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set |
| 94 | by this function. Possibly initialize THIS_CACHE. */ |
| 95 | |
| 96 | void |
| 97 | frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache) |
| 98 | { |
| 99 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 100 | struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data); |
| 101 | struct frame_unwind_table_entry *entry; |
| 102 | |
| 103 | for (entry = table->list; entry != NULL; entry = entry->next) |
| 104 | { |
| 105 | struct cleanup *old_cleanup; |
| 106 | volatile struct gdb_exception ex; |
| 107 | int res = 0; |
| 108 | |
| 109 | old_cleanup = frame_prepare_for_sniffer (this_frame, entry->unwinder); |
| 110 | |
| 111 | TRY_CATCH (ex, RETURN_MASK_ERROR) |
| 112 | { |
| 113 | res = entry->unwinder->sniffer (entry->unwinder, this_frame, |
| 114 | this_cache); |
| 115 | } |
| 116 | if (ex.reason < 0 && ex.error == NOT_AVAILABLE_ERROR) |
| 117 | { |
| 118 | /* This usually means that not even the PC is available, |
| 119 | thus most unwinders aren't able to determine if they're |
| 120 | the best fit. Keep trying. Fallback prologue unwinders |
| 121 | should always accept the frame. */ |
| 122 | } |
| 123 | else if (ex.reason < 0) |
| 124 | throw_exception (ex); |
| 125 | else if (res) |
| 126 | { |
| 127 | discard_cleanups (old_cleanup); |
| 128 | return; |
| 129 | } |
| 130 | |
| 131 | do_cleanups (old_cleanup); |
| 132 | } |
| 133 | internal_error (__FILE__, __LINE__, _("frame_unwind_find_by_frame failed")); |
| 134 | } |
| 135 | |
| 136 | /* A default frame sniffer which always accepts the frame. Used by |
| 137 | fallback prologue unwinders. */ |
| 138 | |
| 139 | int |
| 140 | default_frame_sniffer (const struct frame_unwind *self, |
| 141 | struct frame_info *this_frame, |
| 142 | void **this_prologue_cache) |
| 143 | { |
| 144 | return 1; |
| 145 | } |
| 146 | |
| 147 | /* A default frame unwinder stop_reason callback that always claims |
| 148 | the frame is unwindable. */ |
| 149 | |
| 150 | enum unwind_stop_reason |
| 151 | default_frame_unwind_stop_reason (struct frame_info *this_frame, |
| 152 | void **this_cache) |
| 153 | { |
| 154 | return UNWIND_NO_REASON; |
| 155 | } |
| 156 | |
| 157 | /* Helper functions for value-based register unwinding. These return |
| 158 | a (possibly lazy) value of the appropriate type. */ |
| 159 | |
| 160 | /* Return a value which indicates that FRAME did not save REGNUM. */ |
| 161 | |
| 162 | struct value * |
| 163 | frame_unwind_got_optimized (struct frame_info *frame, int regnum) |
| 164 | { |
| 165 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
| 166 | struct value *reg_val; |
| 167 | |
| 168 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
| 169 | set_value_optimized_out (reg_val, 1); |
| 170 | return reg_val; |
| 171 | } |
| 172 | |
| 173 | /* Return a value which indicates that FRAME copied REGNUM into |
| 174 | register NEW_REGNUM. */ |
| 175 | |
| 176 | struct value * |
| 177 | frame_unwind_got_register (struct frame_info *frame, |
| 178 | int regnum, int new_regnum) |
| 179 | { |
| 180 | return value_of_register_lazy (frame, new_regnum); |
| 181 | } |
| 182 | |
| 183 | /* Return a value which indicates that FRAME saved REGNUM in memory at |
| 184 | ADDR. */ |
| 185 | |
| 186 | struct value * |
| 187 | frame_unwind_got_memory (struct frame_info *frame, int regnum, CORE_ADDR addr) |
| 188 | { |
| 189 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
| 190 | struct value *v = value_at_lazy (register_type (gdbarch, regnum), addr); |
| 191 | |
| 192 | set_value_stack (v, 1); |
| 193 | return v; |
| 194 | } |
| 195 | |
| 196 | /* Return a value which indicates that FRAME's saved version of |
| 197 | REGNUM has a known constant (computed) value of VAL. */ |
| 198 | |
| 199 | struct value * |
| 200 | frame_unwind_got_constant (struct frame_info *frame, int regnum, |
| 201 | ULONGEST val) |
| 202 | { |
| 203 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
| 204 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 205 | struct value *reg_val; |
| 206 | |
| 207 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
| 208 | store_unsigned_integer (value_contents_writeable (reg_val), |
| 209 | register_size (gdbarch, regnum), byte_order, val); |
| 210 | return reg_val; |
| 211 | } |
| 212 | |
| 213 | struct value * |
| 214 | frame_unwind_got_bytes (struct frame_info *frame, int regnum, gdb_byte *buf) |
| 215 | { |
| 216 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
| 217 | struct value *reg_val; |
| 218 | |
| 219 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
| 220 | memcpy (value_contents_raw (reg_val), buf, register_size (gdbarch, regnum)); |
| 221 | return reg_val; |
| 222 | } |
| 223 | |
| 224 | /* Return a value which indicates that FRAME's saved version of REGNUM |
| 225 | has a known constant (computed) value of ADDR. Convert the |
| 226 | CORE_ADDR to a target address if necessary. */ |
| 227 | |
| 228 | struct value * |
| 229 | frame_unwind_got_address (struct frame_info *frame, int regnum, |
| 230 | CORE_ADDR addr) |
| 231 | { |
| 232 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
| 233 | struct value *reg_val; |
| 234 | |
| 235 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
| 236 | pack_long (value_contents_writeable (reg_val), |
| 237 | register_type (gdbarch, regnum), addr); |
| 238 | return reg_val; |
| 239 | } |
| 240 | |
| 241 | /* -Wmissing-prototypes */ |
| 242 | extern initialize_file_ftype _initialize_frame_unwind; |
| 243 | |
| 244 | void |
| 245 | _initialize_frame_unwind (void) |
| 246 | { |
| 247 | frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init); |
| 248 | } |