| 1 | /* Frame unwinder for frames with DWARF Call Frame Information. |
| 2 | |
| 3 | Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation, Inc. |
| 4 | |
| 5 | Contributed by Mark Kettenis. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 3 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "dwarf2expr.h" |
| 24 | #include "elf/dwarf2.h" |
| 25 | #include "frame.h" |
| 26 | #include "frame-base.h" |
| 27 | #include "frame-unwind.h" |
| 28 | #include "gdbcore.h" |
| 29 | #include "gdbtypes.h" |
| 30 | #include "symtab.h" |
| 31 | #include "objfiles.h" |
| 32 | #include "regcache.h" |
| 33 | #include "value.h" |
| 34 | |
| 35 | #include "gdb_assert.h" |
| 36 | #include "gdb_string.h" |
| 37 | |
| 38 | #include "complaints.h" |
| 39 | #include "dwarf2-frame.h" |
| 40 | |
| 41 | struct comp_unit; |
| 42 | |
| 43 | /* Call Frame Information (CFI). */ |
| 44 | |
| 45 | /* Common Information Entry (CIE). */ |
| 46 | |
| 47 | struct dwarf2_cie |
| 48 | { |
| 49 | /* Computation Unit for this CIE. */ |
| 50 | struct comp_unit *unit; |
| 51 | |
| 52 | /* Offset into the .debug_frame section where this CIE was found. |
| 53 | Used to identify this CIE. */ |
| 54 | ULONGEST cie_pointer; |
| 55 | |
| 56 | /* Constant that is factored out of all advance location |
| 57 | instructions. */ |
| 58 | ULONGEST code_alignment_factor; |
| 59 | |
| 60 | /* Constants that is factored out of all offset instructions. */ |
| 61 | LONGEST data_alignment_factor; |
| 62 | |
| 63 | /* Return address column. */ |
| 64 | ULONGEST return_address_register; |
| 65 | |
| 66 | /* Instruction sequence to initialize a register set. */ |
| 67 | gdb_byte *initial_instructions; |
| 68 | gdb_byte *end; |
| 69 | |
| 70 | /* Saved augmentation, in case it's needed later. */ |
| 71 | char *augmentation; |
| 72 | |
| 73 | /* Encoding of addresses. */ |
| 74 | gdb_byte encoding; |
| 75 | |
| 76 | /* Target address size in bytes. */ |
| 77 | int addr_size; |
| 78 | |
| 79 | /* True if a 'z' augmentation existed. */ |
| 80 | unsigned char saw_z_augmentation; |
| 81 | |
| 82 | /* True if an 'S' augmentation existed. */ |
| 83 | unsigned char signal_frame; |
| 84 | |
| 85 | /* The version recorded in the CIE. */ |
| 86 | unsigned char version; |
| 87 | |
| 88 | struct dwarf2_cie *next; |
| 89 | }; |
| 90 | |
| 91 | /* Frame Description Entry (FDE). */ |
| 92 | |
| 93 | struct dwarf2_fde |
| 94 | { |
| 95 | /* CIE for this FDE. */ |
| 96 | struct dwarf2_cie *cie; |
| 97 | |
| 98 | /* First location associated with this FDE. */ |
| 99 | CORE_ADDR initial_location; |
| 100 | |
| 101 | /* Number of bytes of program instructions described by this FDE. */ |
| 102 | CORE_ADDR address_range; |
| 103 | |
| 104 | /* Instruction sequence. */ |
| 105 | gdb_byte *instructions; |
| 106 | gdb_byte *end; |
| 107 | |
| 108 | /* True if this FDE is read from a .eh_frame instead of a .debug_frame |
| 109 | section. */ |
| 110 | unsigned char eh_frame_p; |
| 111 | |
| 112 | struct dwarf2_fde *next; |
| 113 | }; |
| 114 | |
| 115 | /* A minimal decoding of DWARF2 compilation units. We only decode |
| 116 | what's needed to get to the call frame information. */ |
| 117 | |
| 118 | struct comp_unit |
| 119 | { |
| 120 | /* Keep the bfd convenient. */ |
| 121 | bfd *abfd; |
| 122 | |
| 123 | struct objfile *objfile; |
| 124 | |
| 125 | /* Linked list of CIEs for this object. */ |
| 126 | struct dwarf2_cie *cie; |
| 127 | |
| 128 | /* Pointer to the .debug_frame section loaded into memory. */ |
| 129 | gdb_byte *dwarf_frame_buffer; |
| 130 | |
| 131 | /* Length of the loaded .debug_frame section. */ |
| 132 | unsigned long dwarf_frame_size; |
| 133 | |
| 134 | /* Pointer to the .debug_frame section. */ |
| 135 | asection *dwarf_frame_section; |
| 136 | |
| 137 | /* Base for DW_EH_PE_datarel encodings. */ |
| 138 | bfd_vma dbase; |
| 139 | |
| 140 | /* Base for DW_EH_PE_textrel encodings. */ |
| 141 | bfd_vma tbase; |
| 142 | }; |
| 143 | |
| 144 | static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc); |
| 145 | |
| 146 | static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum, |
| 147 | int eh_frame_p); |
| 148 | |
| 149 | static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding, |
| 150 | int ptr_len, gdb_byte *buf, |
| 151 | unsigned int *bytes_read_ptr, |
| 152 | CORE_ADDR func_base); |
| 153 | \f |
| 154 | |
| 155 | /* Structure describing a frame state. */ |
| 156 | |
| 157 | struct dwarf2_frame_state |
| 158 | { |
| 159 | /* Each register save state can be described in terms of a CFA slot, |
| 160 | another register, or a location expression. */ |
| 161 | struct dwarf2_frame_state_reg_info |
| 162 | { |
| 163 | struct dwarf2_frame_state_reg *reg; |
| 164 | int num_regs; |
| 165 | |
| 166 | /* Used to implement DW_CFA_remember_state. */ |
| 167 | struct dwarf2_frame_state_reg_info *prev; |
| 168 | } regs; |
| 169 | |
| 170 | LONGEST cfa_offset; |
| 171 | ULONGEST cfa_reg; |
| 172 | gdb_byte *cfa_exp; |
| 173 | enum { |
| 174 | CFA_UNSET, |
| 175 | CFA_REG_OFFSET, |
| 176 | CFA_EXP |
| 177 | } cfa_how; |
| 178 | |
| 179 | /* The PC described by the current frame state. */ |
| 180 | CORE_ADDR pc; |
| 181 | |
| 182 | /* Initial register set from the CIE. |
| 183 | Used to implement DW_CFA_restore. */ |
| 184 | struct dwarf2_frame_state_reg_info initial; |
| 185 | |
| 186 | /* The information we care about from the CIE. */ |
| 187 | LONGEST data_align; |
| 188 | ULONGEST code_align; |
| 189 | ULONGEST retaddr_column; |
| 190 | |
| 191 | /* Flags for known producer quirks. */ |
| 192 | |
| 193 | /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa |
| 194 | and DW_CFA_def_cfa_offset takes a factored offset. */ |
| 195 | int armcc_cfa_offsets_sf; |
| 196 | |
| 197 | /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that |
| 198 | the CFA is defined as REG - OFFSET rather than REG + OFFSET. */ |
| 199 | int armcc_cfa_offsets_reversed; |
| 200 | }; |
| 201 | |
| 202 | /* Store the length the expression for the CFA in the `cfa_reg' field, |
| 203 | which is unused in that case. */ |
| 204 | #define cfa_exp_len cfa_reg |
| 205 | |
| 206 | /* Assert that the register set RS is large enough to store gdbarch_num_regs |
| 207 | columns. If necessary, enlarge the register set. */ |
| 208 | |
| 209 | static void |
| 210 | dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs, |
| 211 | int num_regs) |
| 212 | { |
| 213 | size_t size = sizeof (struct dwarf2_frame_state_reg); |
| 214 | |
| 215 | if (num_regs <= rs->num_regs) |
| 216 | return; |
| 217 | |
| 218 | rs->reg = (struct dwarf2_frame_state_reg *) |
| 219 | xrealloc (rs->reg, num_regs * size); |
| 220 | |
| 221 | /* Initialize newly allocated registers. */ |
| 222 | memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size); |
| 223 | rs->num_regs = num_regs; |
| 224 | } |
| 225 | |
| 226 | /* Copy the register columns in register set RS into newly allocated |
| 227 | memory and return a pointer to this newly created copy. */ |
| 228 | |
| 229 | static struct dwarf2_frame_state_reg * |
| 230 | dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs) |
| 231 | { |
| 232 | size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg); |
| 233 | struct dwarf2_frame_state_reg *reg; |
| 234 | |
| 235 | reg = (struct dwarf2_frame_state_reg *) xmalloc (size); |
| 236 | memcpy (reg, rs->reg, size); |
| 237 | |
| 238 | return reg; |
| 239 | } |
| 240 | |
| 241 | /* Release the memory allocated to register set RS. */ |
| 242 | |
| 243 | static void |
| 244 | dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs) |
| 245 | { |
| 246 | if (rs) |
| 247 | { |
| 248 | dwarf2_frame_state_free_regs (rs->prev); |
| 249 | |
| 250 | xfree (rs->reg); |
| 251 | xfree (rs); |
| 252 | } |
| 253 | } |
| 254 | |
| 255 | /* Release the memory allocated to the frame state FS. */ |
| 256 | |
| 257 | static void |
| 258 | dwarf2_frame_state_free (void *p) |
| 259 | { |
| 260 | struct dwarf2_frame_state *fs = p; |
| 261 | |
| 262 | dwarf2_frame_state_free_regs (fs->initial.prev); |
| 263 | dwarf2_frame_state_free_regs (fs->regs.prev); |
| 264 | xfree (fs->initial.reg); |
| 265 | xfree (fs->regs.reg); |
| 266 | xfree (fs); |
| 267 | } |
| 268 | \f |
| 269 | |
| 270 | /* Helper functions for execute_stack_op. */ |
| 271 | |
| 272 | static CORE_ADDR |
| 273 | read_reg (void *baton, int reg) |
| 274 | { |
| 275 | struct frame_info *this_frame = (struct frame_info *) baton; |
| 276 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 277 | int regnum; |
| 278 | gdb_byte *buf; |
| 279 | |
| 280 | regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); |
| 281 | |
| 282 | buf = alloca (register_size (gdbarch, regnum)); |
| 283 | get_frame_register (this_frame, regnum, buf); |
| 284 | |
| 285 | /* Convert the register to an integer. This returns a LONGEST |
| 286 | rather than a CORE_ADDR, but unpack_pointer does the same thing |
| 287 | under the covers, and this makes more sense for non-pointer |
| 288 | registers. Maybe read_reg and the associated interfaces should |
| 289 | deal with "struct value" instead of CORE_ADDR. */ |
| 290 | return unpack_long (register_type (gdbarch, regnum), buf); |
| 291 | } |
| 292 | |
| 293 | static void |
| 294 | read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
| 295 | { |
| 296 | read_memory (addr, buf, len); |
| 297 | } |
| 298 | |
| 299 | static void |
| 300 | no_get_frame_base (void *baton, gdb_byte **start, size_t *length) |
| 301 | { |
| 302 | internal_error (__FILE__, __LINE__, |
| 303 | _("Support for DW_OP_fbreg is unimplemented")); |
| 304 | } |
| 305 | |
| 306 | static CORE_ADDR |
| 307 | no_get_tls_address (void *baton, CORE_ADDR offset) |
| 308 | { |
| 309 | internal_error (__FILE__, __LINE__, |
| 310 | _("Support for DW_OP_GNU_push_tls_address is unimplemented")); |
| 311 | } |
| 312 | |
| 313 | /* Execute the required actions for both the DW_CFA_restore and |
| 314 | DW_CFA_restore_extended instructions. */ |
| 315 | static void |
| 316 | dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num, |
| 317 | struct dwarf2_frame_state *fs, int eh_frame_p) |
| 318 | { |
| 319 | ULONGEST reg; |
| 320 | |
| 321 | gdb_assert (fs->initial.reg); |
| 322 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p); |
| 323 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 324 | |
| 325 | /* Check if this register was explicitly initialized in the |
| 326 | CIE initial instructions. If not, default the rule to |
| 327 | UNSPECIFIED. */ |
| 328 | if (reg < fs->initial.num_regs) |
| 329 | fs->regs.reg[reg] = fs->initial.reg[reg]; |
| 330 | else |
| 331 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED; |
| 332 | |
| 333 | if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 334 | complaint (&symfile_complaints, _("\ |
| 335 | incomplete CFI data; DW_CFA_restore unspecified\n\ |
| 336 | register %s (#%d) at 0x%s"), |
| 337 | gdbarch_register_name |
| 338 | (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)), |
| 339 | gdbarch_dwarf2_reg_to_regnum (gdbarch, reg), |
| 340 | paddr (fs->pc)); |
| 341 | } |
| 342 | |
| 343 | static CORE_ADDR |
| 344 | execute_stack_op (gdb_byte *exp, ULONGEST len, int addr_size, |
| 345 | struct frame_info *this_frame, CORE_ADDR initial) |
| 346 | { |
| 347 | struct dwarf_expr_context *ctx; |
| 348 | CORE_ADDR result; |
| 349 | |
| 350 | ctx = new_dwarf_expr_context (); |
| 351 | ctx->addr_size = addr_size; |
| 352 | ctx->baton = this_frame; |
| 353 | ctx->read_reg = read_reg; |
| 354 | ctx->read_mem = read_mem; |
| 355 | ctx->get_frame_base = no_get_frame_base; |
| 356 | ctx->get_tls_address = no_get_tls_address; |
| 357 | |
| 358 | dwarf_expr_push (ctx, initial); |
| 359 | dwarf_expr_eval (ctx, exp, len); |
| 360 | result = dwarf_expr_fetch (ctx, 0); |
| 361 | |
| 362 | if (ctx->in_reg) |
| 363 | result = read_reg (this_frame, result); |
| 364 | |
| 365 | free_dwarf_expr_context (ctx); |
| 366 | |
| 367 | return result; |
| 368 | } |
| 369 | \f |
| 370 | |
| 371 | static void |
| 372 | execute_cfa_program (struct dwarf2_fde *fde, gdb_byte *insn_ptr, |
| 373 | gdb_byte *insn_end, struct frame_info *this_frame, |
| 374 | struct dwarf2_frame_state *fs) |
| 375 | { |
| 376 | int eh_frame_p = fde->eh_frame_p; |
| 377 | CORE_ADDR pc = get_frame_pc (this_frame); |
| 378 | int bytes_read; |
| 379 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 380 | |
| 381 | while (insn_ptr < insn_end && fs->pc <= pc) |
| 382 | { |
| 383 | gdb_byte insn = *insn_ptr++; |
| 384 | ULONGEST utmp, reg; |
| 385 | LONGEST offset; |
| 386 | |
| 387 | if ((insn & 0xc0) == DW_CFA_advance_loc) |
| 388 | fs->pc += (insn & 0x3f) * fs->code_align; |
| 389 | else if ((insn & 0xc0) == DW_CFA_offset) |
| 390 | { |
| 391 | reg = insn & 0x3f; |
| 392 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 393 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 394 | offset = utmp * fs->data_align; |
| 395 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 396 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 397 | fs->regs.reg[reg].loc.offset = offset; |
| 398 | } |
| 399 | else if ((insn & 0xc0) == DW_CFA_restore) |
| 400 | { |
| 401 | reg = insn & 0x3f; |
| 402 | dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p); |
| 403 | } |
| 404 | else |
| 405 | { |
| 406 | switch (insn) |
| 407 | { |
| 408 | case DW_CFA_set_loc: |
| 409 | fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding, |
| 410 | fde->cie->addr_size, insn_ptr, |
| 411 | &bytes_read, fde->initial_location); |
| 412 | /* Apply the objfile offset for relocatable objects. */ |
| 413 | fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets, |
| 414 | SECT_OFF_TEXT (fde->cie->unit->objfile)); |
| 415 | insn_ptr += bytes_read; |
| 416 | break; |
| 417 | |
| 418 | case DW_CFA_advance_loc1: |
| 419 | utmp = extract_unsigned_integer (insn_ptr, 1); |
| 420 | fs->pc += utmp * fs->code_align; |
| 421 | insn_ptr++; |
| 422 | break; |
| 423 | case DW_CFA_advance_loc2: |
| 424 | utmp = extract_unsigned_integer (insn_ptr, 2); |
| 425 | fs->pc += utmp * fs->code_align; |
| 426 | insn_ptr += 2; |
| 427 | break; |
| 428 | case DW_CFA_advance_loc4: |
| 429 | utmp = extract_unsigned_integer (insn_ptr, 4); |
| 430 | fs->pc += utmp * fs->code_align; |
| 431 | insn_ptr += 4; |
| 432 | break; |
| 433 | |
| 434 | case DW_CFA_offset_extended: |
| 435 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 436 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 437 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 438 | offset = utmp * fs->data_align; |
| 439 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 440 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 441 | fs->regs.reg[reg].loc.offset = offset; |
| 442 | break; |
| 443 | |
| 444 | case DW_CFA_restore_extended: |
| 445 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 446 | dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p); |
| 447 | break; |
| 448 | |
| 449 | case DW_CFA_undefined: |
| 450 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 451 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 452 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 453 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED; |
| 454 | break; |
| 455 | |
| 456 | case DW_CFA_same_value: |
| 457 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 458 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 459 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 460 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE; |
| 461 | break; |
| 462 | |
| 463 | case DW_CFA_register: |
| 464 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 465 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 466 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 467 | utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p); |
| 468 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 469 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; |
| 470 | fs->regs.reg[reg].loc.reg = utmp; |
| 471 | break; |
| 472 | |
| 473 | case DW_CFA_remember_state: |
| 474 | { |
| 475 | struct dwarf2_frame_state_reg_info *new_rs; |
| 476 | |
| 477 | new_rs = XMALLOC (struct dwarf2_frame_state_reg_info); |
| 478 | *new_rs = fs->regs; |
| 479 | fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs); |
| 480 | fs->regs.prev = new_rs; |
| 481 | } |
| 482 | break; |
| 483 | |
| 484 | case DW_CFA_restore_state: |
| 485 | { |
| 486 | struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev; |
| 487 | |
| 488 | if (old_rs == NULL) |
| 489 | { |
| 490 | complaint (&symfile_complaints, _("\ |
| 491 | bad CFI data; mismatched DW_CFA_restore_state at 0x%s"), paddr (fs->pc)); |
| 492 | } |
| 493 | else |
| 494 | { |
| 495 | xfree (fs->regs.reg); |
| 496 | fs->regs = *old_rs; |
| 497 | xfree (old_rs); |
| 498 | } |
| 499 | } |
| 500 | break; |
| 501 | |
| 502 | case DW_CFA_def_cfa: |
| 503 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); |
| 504 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 505 | |
| 506 | if (fs->armcc_cfa_offsets_sf) |
| 507 | utmp *= fs->data_align; |
| 508 | |
| 509 | fs->cfa_offset = utmp; |
| 510 | fs->cfa_how = CFA_REG_OFFSET; |
| 511 | break; |
| 512 | |
| 513 | case DW_CFA_def_cfa_register: |
| 514 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); |
| 515 | fs->cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, fs->cfa_reg, |
| 516 | eh_frame_p); |
| 517 | fs->cfa_how = CFA_REG_OFFSET; |
| 518 | break; |
| 519 | |
| 520 | case DW_CFA_def_cfa_offset: |
| 521 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 522 | |
| 523 | if (fs->armcc_cfa_offsets_sf) |
| 524 | utmp *= fs->data_align; |
| 525 | |
| 526 | fs->cfa_offset = utmp; |
| 527 | /* cfa_how deliberately not set. */ |
| 528 | break; |
| 529 | |
| 530 | case DW_CFA_nop: |
| 531 | break; |
| 532 | |
| 533 | case DW_CFA_def_cfa_expression: |
| 534 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_exp_len); |
| 535 | fs->cfa_exp = insn_ptr; |
| 536 | fs->cfa_how = CFA_EXP; |
| 537 | insn_ptr += fs->cfa_exp_len; |
| 538 | break; |
| 539 | |
| 540 | case DW_CFA_expression: |
| 541 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 542 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 543 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 544 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 545 | fs->regs.reg[reg].loc.exp = insn_ptr; |
| 546 | fs->regs.reg[reg].exp_len = utmp; |
| 547 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP; |
| 548 | insn_ptr += utmp; |
| 549 | break; |
| 550 | |
| 551 | case DW_CFA_offset_extended_sf: |
| 552 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 553 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 554 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); |
| 555 | offset *= fs->data_align; |
| 556 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 557 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 558 | fs->regs.reg[reg].loc.offset = offset; |
| 559 | break; |
| 560 | |
| 561 | case DW_CFA_val_offset: |
| 562 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 563 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 564 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 565 | offset = utmp * fs->data_align; |
| 566 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET; |
| 567 | fs->regs.reg[reg].loc.offset = offset; |
| 568 | break; |
| 569 | |
| 570 | case DW_CFA_val_offset_sf: |
| 571 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 572 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 573 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); |
| 574 | offset *= fs->data_align; |
| 575 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET; |
| 576 | fs->regs.reg[reg].loc.offset = offset; |
| 577 | break; |
| 578 | |
| 579 | case DW_CFA_val_expression: |
| 580 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 581 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 582 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 583 | fs->regs.reg[reg].loc.exp = insn_ptr; |
| 584 | fs->regs.reg[reg].exp_len = utmp; |
| 585 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP; |
| 586 | insn_ptr += utmp; |
| 587 | break; |
| 588 | |
| 589 | case DW_CFA_def_cfa_sf: |
| 590 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg); |
| 591 | fs->cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, fs->cfa_reg, |
| 592 | eh_frame_p); |
| 593 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); |
| 594 | fs->cfa_offset = offset * fs->data_align; |
| 595 | fs->cfa_how = CFA_REG_OFFSET; |
| 596 | break; |
| 597 | |
| 598 | case DW_CFA_def_cfa_offset_sf: |
| 599 | insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset); |
| 600 | fs->cfa_offset = offset * fs->data_align; |
| 601 | /* cfa_how deliberately not set. */ |
| 602 | break; |
| 603 | |
| 604 | case DW_CFA_GNU_window_save: |
| 605 | /* This is SPARC-specific code, and contains hard-coded |
| 606 | constants for the register numbering scheme used by |
| 607 | GCC. Rather than having a architecture-specific |
| 608 | operation that's only ever used by a single |
| 609 | architecture, we provide the implementation here. |
| 610 | Incidentally that's what GCC does too in its |
| 611 | unwinder. */ |
| 612 | { |
| 613 | int size = register_size (gdbarch, 0); |
| 614 | dwarf2_frame_state_alloc_regs (&fs->regs, 32); |
| 615 | for (reg = 8; reg < 16; reg++) |
| 616 | { |
| 617 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; |
| 618 | fs->regs.reg[reg].loc.reg = reg + 16; |
| 619 | } |
| 620 | for (reg = 16; reg < 32; reg++) |
| 621 | { |
| 622 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 623 | fs->regs.reg[reg].loc.offset = (reg - 16) * size; |
| 624 | } |
| 625 | } |
| 626 | break; |
| 627 | |
| 628 | case DW_CFA_GNU_args_size: |
| 629 | /* Ignored. */ |
| 630 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| 631 | break; |
| 632 | |
| 633 | case DW_CFA_GNU_negative_offset_extended: |
| 634 | insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| 635 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 636 | insn_ptr = read_uleb128 (insn_ptr, insn_end, &offset); |
| 637 | offset *= fs->data_align; |
| 638 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 639 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 640 | fs->regs.reg[reg].loc.offset = -offset; |
| 641 | break; |
| 642 | |
| 643 | default: |
| 644 | internal_error (__FILE__, __LINE__, _("Unknown CFI encountered.")); |
| 645 | } |
| 646 | } |
| 647 | } |
| 648 | |
| 649 | /* Don't allow remember/restore between CIE and FDE programs. */ |
| 650 | dwarf2_frame_state_free_regs (fs->regs.prev); |
| 651 | fs->regs.prev = NULL; |
| 652 | } |
| 653 | \f |
| 654 | |
| 655 | /* Architecture-specific operations. */ |
| 656 | |
| 657 | /* Per-architecture data key. */ |
| 658 | static struct gdbarch_data *dwarf2_frame_data; |
| 659 | |
| 660 | struct dwarf2_frame_ops |
| 661 | { |
| 662 | /* Pre-initialize the register state REG for register REGNUM. */ |
| 663 | void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *, |
| 664 | struct frame_info *); |
| 665 | |
| 666 | /* Check whether the THIS_FRAME is a signal trampoline. */ |
| 667 | int (*signal_frame_p) (struct gdbarch *, struct frame_info *); |
| 668 | |
| 669 | /* Convert .eh_frame register number to DWARF register number, or |
| 670 | adjust .debug_frame register number. */ |
| 671 | int (*adjust_regnum) (struct gdbarch *, int, int); |
| 672 | }; |
| 673 | |
| 674 | /* Default architecture-specific register state initialization |
| 675 | function. */ |
| 676 | |
| 677 | static void |
| 678 | dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum, |
| 679 | struct dwarf2_frame_state_reg *reg, |
| 680 | struct frame_info *this_frame) |
| 681 | { |
| 682 | /* If we have a register that acts as a program counter, mark it as |
| 683 | a destination for the return address. If we have a register that |
| 684 | serves as the stack pointer, arrange for it to be filled with the |
| 685 | call frame address (CFA). The other registers are marked as |
| 686 | unspecified. |
| 687 | |
| 688 | We copy the return address to the program counter, since many |
| 689 | parts in GDB assume that it is possible to get the return address |
| 690 | by unwinding the program counter register. However, on ISA's |
| 691 | with a dedicated return address register, the CFI usually only |
| 692 | contains information to unwind that return address register. |
| 693 | |
| 694 | The reason we're treating the stack pointer special here is |
| 695 | because in many cases GCC doesn't emit CFI for the stack pointer |
| 696 | and implicitly assumes that it is equal to the CFA. This makes |
| 697 | some sense since the DWARF specification (version 3, draft 8, |
| 698 | p. 102) says that: |
| 699 | |
| 700 | "Typically, the CFA is defined to be the value of the stack |
| 701 | pointer at the call site in the previous frame (which may be |
| 702 | different from its value on entry to the current frame)." |
| 703 | |
| 704 | However, this isn't true for all platforms supported by GCC |
| 705 | (e.g. IBM S/390 and zSeries). Those architectures should provide |
| 706 | their own architecture-specific initialization function. */ |
| 707 | |
| 708 | if (regnum == gdbarch_pc_regnum (gdbarch)) |
| 709 | reg->how = DWARF2_FRAME_REG_RA; |
| 710 | else if (regnum == gdbarch_sp_regnum (gdbarch)) |
| 711 | reg->how = DWARF2_FRAME_REG_CFA; |
| 712 | } |
| 713 | |
| 714 | /* Return a default for the architecture-specific operations. */ |
| 715 | |
| 716 | static void * |
| 717 | dwarf2_frame_init (struct obstack *obstack) |
| 718 | { |
| 719 | struct dwarf2_frame_ops *ops; |
| 720 | |
| 721 | ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops); |
| 722 | ops->init_reg = dwarf2_frame_default_init_reg; |
| 723 | return ops; |
| 724 | } |
| 725 | |
| 726 | /* Set the architecture-specific register state initialization |
| 727 | function for GDBARCH to INIT_REG. */ |
| 728 | |
| 729 | void |
| 730 | dwarf2_frame_set_init_reg (struct gdbarch *gdbarch, |
| 731 | void (*init_reg) (struct gdbarch *, int, |
| 732 | struct dwarf2_frame_state_reg *, |
| 733 | struct frame_info *)) |
| 734 | { |
| 735 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 736 | |
| 737 | ops->init_reg = init_reg; |
| 738 | } |
| 739 | |
| 740 | /* Pre-initialize the register state REG for register REGNUM. */ |
| 741 | |
| 742 | static void |
| 743 | dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum, |
| 744 | struct dwarf2_frame_state_reg *reg, |
| 745 | struct frame_info *this_frame) |
| 746 | { |
| 747 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 748 | |
| 749 | ops->init_reg (gdbarch, regnum, reg, this_frame); |
| 750 | } |
| 751 | |
| 752 | /* Set the architecture-specific signal trampoline recognition |
| 753 | function for GDBARCH to SIGNAL_FRAME_P. */ |
| 754 | |
| 755 | void |
| 756 | dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch, |
| 757 | int (*signal_frame_p) (struct gdbarch *, |
| 758 | struct frame_info *)) |
| 759 | { |
| 760 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 761 | |
| 762 | ops->signal_frame_p = signal_frame_p; |
| 763 | } |
| 764 | |
| 765 | /* Query the architecture-specific signal frame recognizer for |
| 766 | THIS_FRAME. */ |
| 767 | |
| 768 | static int |
| 769 | dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch, |
| 770 | struct frame_info *this_frame) |
| 771 | { |
| 772 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 773 | |
| 774 | if (ops->signal_frame_p == NULL) |
| 775 | return 0; |
| 776 | return ops->signal_frame_p (gdbarch, this_frame); |
| 777 | } |
| 778 | |
| 779 | /* Set the architecture-specific adjustment of .eh_frame and .debug_frame |
| 780 | register numbers. */ |
| 781 | |
| 782 | void |
| 783 | dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch, |
| 784 | int (*adjust_regnum) (struct gdbarch *, |
| 785 | int, int)) |
| 786 | { |
| 787 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 788 | |
| 789 | ops->adjust_regnum = adjust_regnum; |
| 790 | } |
| 791 | |
| 792 | /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame |
| 793 | register. */ |
| 794 | |
| 795 | static int |
| 796 | dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum, int eh_frame_p) |
| 797 | { |
| 798 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 799 | |
| 800 | if (ops->adjust_regnum == NULL) |
| 801 | return regnum; |
| 802 | return ops->adjust_regnum (gdbarch, regnum, eh_frame_p); |
| 803 | } |
| 804 | |
| 805 | static void |
| 806 | dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs, |
| 807 | struct dwarf2_fde *fde) |
| 808 | { |
| 809 | static const char *arm_idents[] = { |
| 810 | "ARM C Compiler, ADS", |
| 811 | "Thumb C Compiler, ADS", |
| 812 | "ARM C++ Compiler, ADS", |
| 813 | "Thumb C++ Compiler, ADS", |
| 814 | "ARM/Thumb C/C++ Compiler, RVCT" |
| 815 | }; |
| 816 | int i; |
| 817 | |
| 818 | struct symtab *s; |
| 819 | |
| 820 | s = find_pc_symtab (fs->pc); |
| 821 | if (s == NULL || s->producer == NULL) |
| 822 | return; |
| 823 | |
| 824 | for (i = 0; i < ARRAY_SIZE (arm_idents); i++) |
| 825 | if (strncmp (s->producer, arm_idents[i], strlen (arm_idents[i])) == 0) |
| 826 | { |
| 827 | if (fde->cie->version == 1) |
| 828 | fs->armcc_cfa_offsets_sf = 1; |
| 829 | |
| 830 | if (fde->cie->version == 1) |
| 831 | fs->armcc_cfa_offsets_reversed = 1; |
| 832 | |
| 833 | /* The reversed offset problem is present in some compilers |
| 834 | using DWARF3, but it was eventually fixed. Check the ARM |
| 835 | defined augmentations, which are in the format "armcc" followed |
| 836 | by a list of one-character options. The "+" option means |
| 837 | this problem is fixed (no quirk needed). If the armcc |
| 838 | augmentation is missing, the quirk is needed. */ |
| 839 | if (fde->cie->version == 3 |
| 840 | && (strncmp (fde->cie->augmentation, "armcc", 5) != 0 |
| 841 | || strchr (fde->cie->augmentation + 5, '+') == NULL)) |
| 842 | fs->armcc_cfa_offsets_reversed = 1; |
| 843 | |
| 844 | return; |
| 845 | } |
| 846 | } |
| 847 | \f |
| 848 | |
| 849 | struct dwarf2_frame_cache |
| 850 | { |
| 851 | /* DWARF Call Frame Address. */ |
| 852 | CORE_ADDR cfa; |
| 853 | |
| 854 | /* Set if the return address column was marked as undefined. */ |
| 855 | int undefined_retaddr; |
| 856 | |
| 857 | /* Saved registers, indexed by GDB register number, not by DWARF |
| 858 | register number. */ |
| 859 | struct dwarf2_frame_state_reg *reg; |
| 860 | |
| 861 | /* Return address register. */ |
| 862 | struct dwarf2_frame_state_reg retaddr_reg; |
| 863 | |
| 864 | /* Target address size in bytes. */ |
| 865 | int addr_size; |
| 866 | }; |
| 867 | |
| 868 | static struct dwarf2_frame_cache * |
| 869 | dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache) |
| 870 | { |
| 871 | struct cleanup *old_chain; |
| 872 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 873 | const int num_regs = gdbarch_num_regs (gdbarch) |
| 874 | + gdbarch_num_pseudo_regs (gdbarch); |
| 875 | struct dwarf2_frame_cache *cache; |
| 876 | struct dwarf2_frame_state *fs; |
| 877 | struct dwarf2_fde *fde; |
| 878 | |
| 879 | if (*this_cache) |
| 880 | return *this_cache; |
| 881 | |
| 882 | /* Allocate a new cache. */ |
| 883 | cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache); |
| 884 | cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg); |
| 885 | |
| 886 | /* Allocate and initialize the frame state. */ |
| 887 | fs = XMALLOC (struct dwarf2_frame_state); |
| 888 | memset (fs, 0, sizeof (struct dwarf2_frame_state)); |
| 889 | old_chain = make_cleanup (dwarf2_frame_state_free, fs); |
| 890 | |
| 891 | /* Unwind the PC. |
| 892 | |
| 893 | Note that if the next frame is never supposed to return (i.e. a call |
| 894 | to abort), the compiler might optimize away the instruction at |
| 895 | its return address. As a result the return address will |
| 896 | point at some random instruction, and the CFI for that |
| 897 | instruction is probably worthless to us. GCC's unwinder solves |
| 898 | this problem by substracting 1 from the return address to get an |
| 899 | address in the middle of a presumed call instruction (or the |
| 900 | instruction in the associated delay slot). This should only be |
| 901 | done for "normal" frames and not for resume-type frames (signal |
| 902 | handlers, sentinel frames, dummy frames). The function |
| 903 | frame_unwind_address_in_block does just this. It's not clear how |
| 904 | reliable the method is though; there is the potential for the |
| 905 | register state pre-call being different to that on return. */ |
| 906 | fs->pc = get_frame_address_in_block (this_frame); |
| 907 | |
| 908 | /* Find the correct FDE. */ |
| 909 | fde = dwarf2_frame_find_fde (&fs->pc); |
| 910 | gdb_assert (fde != NULL); |
| 911 | |
| 912 | /* Extract any interesting information from the CIE. */ |
| 913 | fs->data_align = fde->cie->data_alignment_factor; |
| 914 | fs->code_align = fde->cie->code_alignment_factor; |
| 915 | fs->retaddr_column = fde->cie->return_address_register; |
| 916 | cache->addr_size = fde->cie->addr_size; |
| 917 | |
| 918 | /* Check for "quirks" - known bugs in producers. */ |
| 919 | dwarf2_frame_find_quirks (fs, fde); |
| 920 | |
| 921 | /* First decode all the insns in the CIE. */ |
| 922 | execute_cfa_program (fde, fde->cie->initial_instructions, |
| 923 | fde->cie->end, this_frame, fs); |
| 924 | |
| 925 | /* Save the initialized register set. */ |
| 926 | fs->initial = fs->regs; |
| 927 | fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs); |
| 928 | |
| 929 | /* Then decode the insns in the FDE up to our target PC. */ |
| 930 | execute_cfa_program (fde, fde->instructions, fde->end, this_frame, fs); |
| 931 | |
| 932 | /* Calculate the CFA. */ |
| 933 | switch (fs->cfa_how) |
| 934 | { |
| 935 | case CFA_REG_OFFSET: |
| 936 | cache->cfa = read_reg (this_frame, fs->cfa_reg); |
| 937 | if (fs->armcc_cfa_offsets_reversed) |
| 938 | cache->cfa -= fs->cfa_offset; |
| 939 | else |
| 940 | cache->cfa += fs->cfa_offset; |
| 941 | break; |
| 942 | |
| 943 | case CFA_EXP: |
| 944 | cache->cfa = |
| 945 | execute_stack_op (fs->cfa_exp, fs->cfa_exp_len, |
| 946 | cache->addr_size, this_frame, 0); |
| 947 | break; |
| 948 | |
| 949 | default: |
| 950 | internal_error (__FILE__, __LINE__, _("Unknown CFA rule.")); |
| 951 | } |
| 952 | |
| 953 | /* Initialize the register state. */ |
| 954 | { |
| 955 | int regnum; |
| 956 | |
| 957 | for (regnum = 0; regnum < num_regs; regnum++) |
| 958 | dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame); |
| 959 | } |
| 960 | |
| 961 | /* Go through the DWARF2 CFI generated table and save its register |
| 962 | location information in the cache. Note that we don't skip the |
| 963 | return address column; it's perfectly all right for it to |
| 964 | correspond to a real register. If it doesn't correspond to a |
| 965 | real register, or if we shouldn't treat it as such, |
| 966 | gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside |
| 967 | the range [0, gdbarch_num_regs). */ |
| 968 | { |
| 969 | int column; /* CFI speak for "register number". */ |
| 970 | |
| 971 | for (column = 0; column < fs->regs.num_regs; column++) |
| 972 | { |
| 973 | /* Use the GDB register number as the destination index. */ |
| 974 | int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column); |
| 975 | |
| 976 | /* If there's no corresponding GDB register, ignore it. */ |
| 977 | if (regnum < 0 || regnum >= num_regs) |
| 978 | continue; |
| 979 | |
| 980 | /* NOTE: cagney/2003-09-05: CFI should specify the disposition |
| 981 | of all debug info registers. If it doesn't, complain (but |
| 982 | not too loudly). It turns out that GCC assumes that an |
| 983 | unspecified register implies "same value" when CFI (draft |
| 984 | 7) specifies nothing at all. Such a register could equally |
| 985 | be interpreted as "undefined". Also note that this check |
| 986 | isn't sufficient; it only checks that all registers in the |
| 987 | range [0 .. max column] are specified, and won't detect |
| 988 | problems when a debug info register falls outside of the |
| 989 | table. We need a way of iterating through all the valid |
| 990 | DWARF2 register numbers. */ |
| 991 | if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 992 | { |
| 993 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 994 | complaint (&symfile_complaints, _("\ |
| 995 | incomplete CFI data; unspecified registers (e.g., %s) at 0x%s"), |
| 996 | gdbarch_register_name (gdbarch, regnum), |
| 997 | paddr_nz (fs->pc)); |
| 998 | } |
| 999 | else |
| 1000 | cache->reg[regnum] = fs->regs.reg[column]; |
| 1001 | } |
| 1002 | } |
| 1003 | |
| 1004 | /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information |
| 1005 | we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */ |
| 1006 | { |
| 1007 | int regnum; |
| 1008 | |
| 1009 | for (regnum = 0; regnum < num_regs; regnum++) |
| 1010 | { |
| 1011 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA |
| 1012 | || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET) |
| 1013 | { |
| 1014 | struct dwarf2_frame_state_reg *retaddr_reg = |
| 1015 | &fs->regs.reg[fs->retaddr_column]; |
| 1016 | |
| 1017 | /* It seems rather bizarre to specify an "empty" column as |
| 1018 | the return adress column. However, this is exactly |
| 1019 | what GCC does on some targets. It turns out that GCC |
| 1020 | assumes that the return address can be found in the |
| 1021 | register corresponding to the return address column. |
| 1022 | Incidentally, that's how we should treat a return |
| 1023 | address column specifying "same value" too. */ |
| 1024 | if (fs->retaddr_column < fs->regs.num_regs |
| 1025 | && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED |
| 1026 | && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE) |
| 1027 | { |
| 1028 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) |
| 1029 | cache->reg[regnum] = *retaddr_reg; |
| 1030 | else |
| 1031 | cache->retaddr_reg = *retaddr_reg; |
| 1032 | } |
| 1033 | else |
| 1034 | { |
| 1035 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) |
| 1036 | { |
| 1037 | cache->reg[regnum].loc.reg = fs->retaddr_column; |
| 1038 | cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG; |
| 1039 | } |
| 1040 | else |
| 1041 | { |
| 1042 | cache->retaddr_reg.loc.reg = fs->retaddr_column; |
| 1043 | cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG; |
| 1044 | } |
| 1045 | } |
| 1046 | } |
| 1047 | } |
| 1048 | } |
| 1049 | |
| 1050 | if (fs->retaddr_column < fs->regs.num_regs |
| 1051 | && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED) |
| 1052 | cache->undefined_retaddr = 1; |
| 1053 | |
| 1054 | do_cleanups (old_chain); |
| 1055 | |
| 1056 | *this_cache = cache; |
| 1057 | return cache; |
| 1058 | } |
| 1059 | |
| 1060 | static void |
| 1061 | dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache, |
| 1062 | struct frame_id *this_id) |
| 1063 | { |
| 1064 | struct dwarf2_frame_cache *cache = |
| 1065 | dwarf2_frame_cache (this_frame, this_cache); |
| 1066 | |
| 1067 | if (cache->undefined_retaddr) |
| 1068 | return; |
| 1069 | |
| 1070 | (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame)); |
| 1071 | } |
| 1072 | |
| 1073 | static struct value * |
| 1074 | dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache, |
| 1075 | int regnum) |
| 1076 | { |
| 1077 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 1078 | struct dwarf2_frame_cache *cache = |
| 1079 | dwarf2_frame_cache (this_frame, this_cache); |
| 1080 | CORE_ADDR addr; |
| 1081 | int realnum; |
| 1082 | |
| 1083 | switch (cache->reg[regnum].how) |
| 1084 | { |
| 1085 | case DWARF2_FRAME_REG_UNDEFINED: |
| 1086 | /* If CFI explicitly specified that the value isn't defined, |
| 1087 | mark it as optimized away; the value isn't available. */ |
| 1088 | return frame_unwind_got_optimized (this_frame, regnum); |
| 1089 | |
| 1090 | case DWARF2_FRAME_REG_SAVED_OFFSET: |
| 1091 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1092 | return frame_unwind_got_memory (this_frame, regnum, addr); |
| 1093 | |
| 1094 | case DWARF2_FRAME_REG_SAVED_REG: |
| 1095 | realnum |
| 1096 | = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg); |
| 1097 | return frame_unwind_got_register (this_frame, regnum, realnum); |
| 1098 | |
| 1099 | case DWARF2_FRAME_REG_SAVED_EXP: |
| 1100 | addr = execute_stack_op (cache->reg[regnum].loc.exp, |
| 1101 | cache->reg[regnum].exp_len, |
| 1102 | cache->addr_size, this_frame, cache->cfa); |
| 1103 | return frame_unwind_got_memory (this_frame, regnum, addr); |
| 1104 | |
| 1105 | case DWARF2_FRAME_REG_SAVED_VAL_OFFSET: |
| 1106 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1107 | return frame_unwind_got_constant (this_frame, regnum, addr); |
| 1108 | |
| 1109 | case DWARF2_FRAME_REG_SAVED_VAL_EXP: |
| 1110 | addr = execute_stack_op (cache->reg[regnum].loc.exp, |
| 1111 | cache->reg[regnum].exp_len, |
| 1112 | cache->addr_size, this_frame, cache->cfa); |
| 1113 | return frame_unwind_got_constant (this_frame, regnum, addr); |
| 1114 | |
| 1115 | case DWARF2_FRAME_REG_UNSPECIFIED: |
| 1116 | /* GCC, in its infinite wisdom decided to not provide unwind |
| 1117 | information for registers that are "same value". Since |
| 1118 | DWARF2 (3 draft 7) doesn't define such behavior, said |
| 1119 | registers are actually undefined (which is different to CFI |
| 1120 | "undefined"). Code above issues a complaint about this. |
| 1121 | Here just fudge the books, assume GCC, and that the value is |
| 1122 | more inner on the stack. */ |
| 1123 | return frame_unwind_got_register (this_frame, regnum, regnum); |
| 1124 | |
| 1125 | case DWARF2_FRAME_REG_SAME_VALUE: |
| 1126 | return frame_unwind_got_register (this_frame, regnum, regnum); |
| 1127 | |
| 1128 | case DWARF2_FRAME_REG_CFA: |
| 1129 | return frame_unwind_got_address (this_frame, regnum, cache->cfa); |
| 1130 | |
| 1131 | case DWARF2_FRAME_REG_CFA_OFFSET: |
| 1132 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1133 | return frame_unwind_got_address (this_frame, regnum, addr); |
| 1134 | |
| 1135 | case DWARF2_FRAME_REG_RA_OFFSET: |
| 1136 | addr = cache->reg[regnum].loc.offset; |
| 1137 | regnum = gdbarch_dwarf2_reg_to_regnum |
| 1138 | (gdbarch, cache->retaddr_reg.loc.reg); |
| 1139 | addr += get_frame_register_unsigned (this_frame, regnum); |
| 1140 | return frame_unwind_got_address (this_frame, regnum, addr); |
| 1141 | |
| 1142 | case DWARF2_FRAME_REG_FN: |
| 1143 | return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum); |
| 1144 | |
| 1145 | default: |
| 1146 | internal_error (__FILE__, __LINE__, _("Unknown register rule.")); |
| 1147 | } |
| 1148 | } |
| 1149 | |
| 1150 | static int |
| 1151 | dwarf2_frame_sniffer (const struct frame_unwind *self, |
| 1152 | struct frame_info *this_frame, void **this_cache) |
| 1153 | { |
| 1154 | /* Grab an address that is guarenteed to reside somewhere within the |
| 1155 | function. get_frame_pc(), with a no-return next function, can |
| 1156 | end up returning something past the end of this function's body. |
| 1157 | If the frame we're sniffing for is a signal frame whose start |
| 1158 | address is placed on the stack by the OS, its FDE must |
| 1159 | extend one byte before its start address or we could potentially |
| 1160 | select the FDE of the previous function. */ |
| 1161 | CORE_ADDR block_addr = get_frame_address_in_block (this_frame); |
| 1162 | struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr); |
| 1163 | if (!fde) |
| 1164 | return 0; |
| 1165 | |
| 1166 | /* On some targets, signal trampolines may have unwind information. |
| 1167 | We need to recognize them so that we set the frame type |
| 1168 | correctly. */ |
| 1169 | |
| 1170 | if (fde->cie->signal_frame |
| 1171 | || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame), |
| 1172 | this_frame)) |
| 1173 | return self->type == SIGTRAMP_FRAME; |
| 1174 | |
| 1175 | return self->type != SIGTRAMP_FRAME; |
| 1176 | } |
| 1177 | |
| 1178 | static const struct frame_unwind dwarf2_frame_unwind = |
| 1179 | { |
| 1180 | NORMAL_FRAME, |
| 1181 | dwarf2_frame_this_id, |
| 1182 | dwarf2_frame_prev_register, |
| 1183 | NULL, |
| 1184 | dwarf2_frame_sniffer |
| 1185 | }; |
| 1186 | |
| 1187 | static const struct frame_unwind dwarf2_signal_frame_unwind = |
| 1188 | { |
| 1189 | SIGTRAMP_FRAME, |
| 1190 | dwarf2_frame_this_id, |
| 1191 | dwarf2_frame_prev_register, |
| 1192 | NULL, |
| 1193 | dwarf2_frame_sniffer |
| 1194 | }; |
| 1195 | |
| 1196 | /* Append the DWARF-2 frame unwinders to GDBARCH's list. */ |
| 1197 | |
| 1198 | void |
| 1199 | dwarf2_append_unwinders (struct gdbarch *gdbarch) |
| 1200 | { |
| 1201 | frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind); |
| 1202 | frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind); |
| 1203 | } |
| 1204 | \f |
| 1205 | |
| 1206 | /* There is no explicitly defined relationship between the CFA and the |
| 1207 | location of frame's local variables and arguments/parameters. |
| 1208 | Therefore, frame base methods on this page should probably only be |
| 1209 | used as a last resort, just to avoid printing total garbage as a |
| 1210 | response to the "info frame" command. */ |
| 1211 | |
| 1212 | static CORE_ADDR |
| 1213 | dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache) |
| 1214 | { |
| 1215 | struct dwarf2_frame_cache *cache = |
| 1216 | dwarf2_frame_cache (this_frame, this_cache); |
| 1217 | |
| 1218 | return cache->cfa; |
| 1219 | } |
| 1220 | |
| 1221 | static const struct frame_base dwarf2_frame_base = |
| 1222 | { |
| 1223 | &dwarf2_frame_unwind, |
| 1224 | dwarf2_frame_base_address, |
| 1225 | dwarf2_frame_base_address, |
| 1226 | dwarf2_frame_base_address |
| 1227 | }; |
| 1228 | |
| 1229 | const struct frame_base * |
| 1230 | dwarf2_frame_base_sniffer (struct frame_info *this_frame) |
| 1231 | { |
| 1232 | CORE_ADDR block_addr = get_frame_address_in_block (this_frame); |
| 1233 | if (dwarf2_frame_find_fde (&block_addr)) |
| 1234 | return &dwarf2_frame_base; |
| 1235 | |
| 1236 | return NULL; |
| 1237 | } |
| 1238 | \f |
| 1239 | const struct objfile_data *dwarf2_frame_objfile_data; |
| 1240 | |
| 1241 | static unsigned int |
| 1242 | read_1_byte (bfd *abfd, gdb_byte *buf) |
| 1243 | { |
| 1244 | return bfd_get_8 (abfd, buf); |
| 1245 | } |
| 1246 | |
| 1247 | static unsigned int |
| 1248 | read_4_bytes (bfd *abfd, gdb_byte *buf) |
| 1249 | { |
| 1250 | return bfd_get_32 (abfd, buf); |
| 1251 | } |
| 1252 | |
| 1253 | static ULONGEST |
| 1254 | read_8_bytes (bfd *abfd, gdb_byte *buf) |
| 1255 | { |
| 1256 | return bfd_get_64 (abfd, buf); |
| 1257 | } |
| 1258 | |
| 1259 | static ULONGEST |
| 1260 | read_unsigned_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
| 1261 | { |
| 1262 | ULONGEST result; |
| 1263 | unsigned int num_read; |
| 1264 | int shift; |
| 1265 | gdb_byte byte; |
| 1266 | |
| 1267 | result = 0; |
| 1268 | shift = 0; |
| 1269 | num_read = 0; |
| 1270 | |
| 1271 | do |
| 1272 | { |
| 1273 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); |
| 1274 | buf++; |
| 1275 | num_read++; |
| 1276 | result |= ((byte & 0x7f) << shift); |
| 1277 | shift += 7; |
| 1278 | } |
| 1279 | while (byte & 0x80); |
| 1280 | |
| 1281 | *bytes_read_ptr = num_read; |
| 1282 | |
| 1283 | return result; |
| 1284 | } |
| 1285 | |
| 1286 | static LONGEST |
| 1287 | read_signed_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
| 1288 | { |
| 1289 | LONGEST result; |
| 1290 | int shift; |
| 1291 | unsigned int num_read; |
| 1292 | gdb_byte byte; |
| 1293 | |
| 1294 | result = 0; |
| 1295 | shift = 0; |
| 1296 | num_read = 0; |
| 1297 | |
| 1298 | do |
| 1299 | { |
| 1300 | byte = bfd_get_8 (abfd, (bfd_byte *) buf); |
| 1301 | buf++; |
| 1302 | num_read++; |
| 1303 | result |= ((byte & 0x7f) << shift); |
| 1304 | shift += 7; |
| 1305 | } |
| 1306 | while (byte & 0x80); |
| 1307 | |
| 1308 | if (shift < 8 * sizeof (result) && (byte & 0x40)) |
| 1309 | result |= -(((LONGEST)1) << shift); |
| 1310 | |
| 1311 | *bytes_read_ptr = num_read; |
| 1312 | |
| 1313 | return result; |
| 1314 | } |
| 1315 | |
| 1316 | static ULONGEST |
| 1317 | read_initial_length (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr) |
| 1318 | { |
| 1319 | LONGEST result; |
| 1320 | |
| 1321 | result = bfd_get_32 (abfd, buf); |
| 1322 | if (result == 0xffffffff) |
| 1323 | { |
| 1324 | result = bfd_get_64 (abfd, buf + 4); |
| 1325 | *bytes_read_ptr = 12; |
| 1326 | } |
| 1327 | else |
| 1328 | *bytes_read_ptr = 4; |
| 1329 | |
| 1330 | return result; |
| 1331 | } |
| 1332 | \f |
| 1333 | |
| 1334 | /* Pointer encoding helper functions. */ |
| 1335 | |
| 1336 | /* GCC supports exception handling based on DWARF2 CFI. However, for |
| 1337 | technical reasons, it encodes addresses in its FDE's in a different |
| 1338 | way. Several "pointer encodings" are supported. The encoding |
| 1339 | that's used for a particular FDE is determined by the 'R' |
| 1340 | augmentation in the associated CIE. The argument of this |
| 1341 | augmentation is a single byte. |
| 1342 | |
| 1343 | The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a |
| 1344 | LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether |
| 1345 | the address is signed or unsigned. Bits 4, 5 and 6 encode how the |
| 1346 | address should be interpreted (absolute, relative to the current |
| 1347 | position in the FDE, ...). Bit 7, indicates that the address |
| 1348 | should be dereferenced. */ |
| 1349 | |
| 1350 | static gdb_byte |
| 1351 | encoding_for_size (unsigned int size) |
| 1352 | { |
| 1353 | switch (size) |
| 1354 | { |
| 1355 | case 2: |
| 1356 | return DW_EH_PE_udata2; |
| 1357 | case 4: |
| 1358 | return DW_EH_PE_udata4; |
| 1359 | case 8: |
| 1360 | return DW_EH_PE_udata8; |
| 1361 | default: |
| 1362 | internal_error (__FILE__, __LINE__, _("Unsupported address size")); |
| 1363 | } |
| 1364 | } |
| 1365 | |
| 1366 | static CORE_ADDR |
| 1367 | read_encoded_value (struct comp_unit *unit, gdb_byte encoding, |
| 1368 | int ptr_len, gdb_byte *buf, unsigned int *bytes_read_ptr, |
| 1369 | CORE_ADDR func_base) |
| 1370 | { |
| 1371 | ptrdiff_t offset; |
| 1372 | CORE_ADDR base; |
| 1373 | |
| 1374 | /* GCC currently doesn't generate DW_EH_PE_indirect encodings for |
| 1375 | FDE's. */ |
| 1376 | if (encoding & DW_EH_PE_indirect) |
| 1377 | internal_error (__FILE__, __LINE__, |
| 1378 | _("Unsupported encoding: DW_EH_PE_indirect")); |
| 1379 | |
| 1380 | *bytes_read_ptr = 0; |
| 1381 | |
| 1382 | switch (encoding & 0x70) |
| 1383 | { |
| 1384 | case DW_EH_PE_absptr: |
| 1385 | base = 0; |
| 1386 | break; |
| 1387 | case DW_EH_PE_pcrel: |
| 1388 | base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section); |
| 1389 | base += (buf - unit->dwarf_frame_buffer); |
| 1390 | break; |
| 1391 | case DW_EH_PE_datarel: |
| 1392 | base = unit->dbase; |
| 1393 | break; |
| 1394 | case DW_EH_PE_textrel: |
| 1395 | base = unit->tbase; |
| 1396 | break; |
| 1397 | case DW_EH_PE_funcrel: |
| 1398 | base = func_base; |
| 1399 | break; |
| 1400 | case DW_EH_PE_aligned: |
| 1401 | base = 0; |
| 1402 | offset = buf - unit->dwarf_frame_buffer; |
| 1403 | if ((offset % ptr_len) != 0) |
| 1404 | { |
| 1405 | *bytes_read_ptr = ptr_len - (offset % ptr_len); |
| 1406 | buf += *bytes_read_ptr; |
| 1407 | } |
| 1408 | break; |
| 1409 | default: |
| 1410 | internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding")); |
| 1411 | } |
| 1412 | |
| 1413 | if ((encoding & 0x07) == 0x00) |
| 1414 | { |
| 1415 | encoding |= encoding_for_size (ptr_len); |
| 1416 | if (bfd_get_sign_extend_vma (unit->abfd)) |
| 1417 | encoding |= DW_EH_PE_signed; |
| 1418 | } |
| 1419 | |
| 1420 | switch (encoding & 0x0f) |
| 1421 | { |
| 1422 | case DW_EH_PE_uleb128: |
| 1423 | { |
| 1424 | ULONGEST value; |
| 1425 | gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
| 1426 | *bytes_read_ptr += read_uleb128 (buf, end_buf, &value) - buf; |
| 1427 | return base + value; |
| 1428 | } |
| 1429 | case DW_EH_PE_udata2: |
| 1430 | *bytes_read_ptr += 2; |
| 1431 | return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf)); |
| 1432 | case DW_EH_PE_udata4: |
| 1433 | *bytes_read_ptr += 4; |
| 1434 | return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf)); |
| 1435 | case DW_EH_PE_udata8: |
| 1436 | *bytes_read_ptr += 8; |
| 1437 | return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf)); |
| 1438 | case DW_EH_PE_sleb128: |
| 1439 | { |
| 1440 | LONGEST value; |
| 1441 | gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
| 1442 | *bytes_read_ptr += read_sleb128 (buf, end_buf, &value) - buf; |
| 1443 | return base + value; |
| 1444 | } |
| 1445 | case DW_EH_PE_sdata2: |
| 1446 | *bytes_read_ptr += 2; |
| 1447 | return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf)); |
| 1448 | case DW_EH_PE_sdata4: |
| 1449 | *bytes_read_ptr += 4; |
| 1450 | return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf)); |
| 1451 | case DW_EH_PE_sdata8: |
| 1452 | *bytes_read_ptr += 8; |
| 1453 | return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf)); |
| 1454 | default: |
| 1455 | internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding")); |
| 1456 | } |
| 1457 | } |
| 1458 | \f |
| 1459 | |
| 1460 | /* GCC uses a single CIE for all FDEs in a .debug_frame section. |
| 1461 | That's why we use a simple linked list here. */ |
| 1462 | |
| 1463 | static struct dwarf2_cie * |
| 1464 | find_cie (struct comp_unit *unit, ULONGEST cie_pointer) |
| 1465 | { |
| 1466 | struct dwarf2_cie *cie = unit->cie; |
| 1467 | |
| 1468 | while (cie) |
| 1469 | { |
| 1470 | if (cie->cie_pointer == cie_pointer) |
| 1471 | return cie; |
| 1472 | |
| 1473 | cie = cie->next; |
| 1474 | } |
| 1475 | |
| 1476 | return NULL; |
| 1477 | } |
| 1478 | |
| 1479 | static void |
| 1480 | add_cie (struct comp_unit *unit, struct dwarf2_cie *cie) |
| 1481 | { |
| 1482 | cie->next = unit->cie; |
| 1483 | unit->cie = cie; |
| 1484 | cie->unit = unit; |
| 1485 | } |
| 1486 | |
| 1487 | /* Find the FDE for *PC. Return a pointer to the FDE, and store the |
| 1488 | inital location associated with it into *PC. */ |
| 1489 | |
| 1490 | static struct dwarf2_fde * |
| 1491 | dwarf2_frame_find_fde (CORE_ADDR *pc) |
| 1492 | { |
| 1493 | struct objfile *objfile; |
| 1494 | |
| 1495 | ALL_OBJFILES (objfile) |
| 1496 | { |
| 1497 | struct dwarf2_fde *fde; |
| 1498 | CORE_ADDR offset; |
| 1499 | |
| 1500 | fde = objfile_data (objfile, dwarf2_frame_objfile_data); |
| 1501 | if (fde == NULL) |
| 1502 | continue; |
| 1503 | |
| 1504 | gdb_assert (objfile->section_offsets); |
| 1505 | offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); |
| 1506 | |
| 1507 | while (fde) |
| 1508 | { |
| 1509 | if (*pc >= fde->initial_location + offset |
| 1510 | && *pc < fde->initial_location + offset + fde->address_range) |
| 1511 | { |
| 1512 | *pc = fde->initial_location + offset; |
| 1513 | return fde; |
| 1514 | } |
| 1515 | |
| 1516 | fde = fde->next; |
| 1517 | } |
| 1518 | } |
| 1519 | |
| 1520 | return NULL; |
| 1521 | } |
| 1522 | |
| 1523 | static void |
| 1524 | add_fde (struct comp_unit *unit, struct dwarf2_fde *fde) |
| 1525 | { |
| 1526 | fde->next = objfile_data (unit->objfile, dwarf2_frame_objfile_data); |
| 1527 | set_objfile_data (unit->objfile, dwarf2_frame_objfile_data, fde); |
| 1528 | } |
| 1529 | |
| 1530 | #ifdef CC_HAS_LONG_LONG |
| 1531 | #define DW64_CIE_ID 0xffffffffffffffffULL |
| 1532 | #else |
| 1533 | #define DW64_CIE_ID ~0 |
| 1534 | #endif |
| 1535 | |
| 1536 | static gdb_byte *decode_frame_entry (struct comp_unit *unit, gdb_byte *start, |
| 1537 | int eh_frame_p); |
| 1538 | |
| 1539 | /* Decode the next CIE or FDE. Return NULL if invalid input, otherwise |
| 1540 | the next byte to be processed. */ |
| 1541 | static gdb_byte * |
| 1542 | decode_frame_entry_1 (struct comp_unit *unit, gdb_byte *start, int eh_frame_p) |
| 1543 | { |
| 1544 | struct gdbarch *gdbarch = get_objfile_arch (unit->objfile); |
| 1545 | gdb_byte *buf, *end; |
| 1546 | LONGEST length; |
| 1547 | unsigned int bytes_read; |
| 1548 | int dwarf64_p; |
| 1549 | ULONGEST cie_id; |
| 1550 | ULONGEST cie_pointer; |
| 1551 | |
| 1552 | buf = start; |
| 1553 | length = read_initial_length (unit->abfd, buf, &bytes_read); |
| 1554 | buf += bytes_read; |
| 1555 | end = buf + length; |
| 1556 | |
| 1557 | /* Are we still within the section? */ |
| 1558 | if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 1559 | return NULL; |
| 1560 | |
| 1561 | if (length == 0) |
| 1562 | return end; |
| 1563 | |
| 1564 | /* Distinguish between 32 and 64-bit encoded frame info. */ |
| 1565 | dwarf64_p = (bytes_read == 12); |
| 1566 | |
| 1567 | /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */ |
| 1568 | if (eh_frame_p) |
| 1569 | cie_id = 0; |
| 1570 | else if (dwarf64_p) |
| 1571 | cie_id = DW64_CIE_ID; |
| 1572 | else |
| 1573 | cie_id = DW_CIE_ID; |
| 1574 | |
| 1575 | if (dwarf64_p) |
| 1576 | { |
| 1577 | cie_pointer = read_8_bytes (unit->abfd, buf); |
| 1578 | buf += 8; |
| 1579 | } |
| 1580 | else |
| 1581 | { |
| 1582 | cie_pointer = read_4_bytes (unit->abfd, buf); |
| 1583 | buf += 4; |
| 1584 | } |
| 1585 | |
| 1586 | if (cie_pointer == cie_id) |
| 1587 | { |
| 1588 | /* This is a CIE. */ |
| 1589 | struct dwarf2_cie *cie; |
| 1590 | char *augmentation; |
| 1591 | unsigned int cie_version; |
| 1592 | |
| 1593 | /* Record the offset into the .debug_frame section of this CIE. */ |
| 1594 | cie_pointer = start - unit->dwarf_frame_buffer; |
| 1595 | |
| 1596 | /* Check whether we've already read it. */ |
| 1597 | if (find_cie (unit, cie_pointer)) |
| 1598 | return end; |
| 1599 | |
| 1600 | cie = (struct dwarf2_cie *) |
| 1601 | obstack_alloc (&unit->objfile->objfile_obstack, |
| 1602 | sizeof (struct dwarf2_cie)); |
| 1603 | cie->initial_instructions = NULL; |
| 1604 | cie->cie_pointer = cie_pointer; |
| 1605 | |
| 1606 | /* The encoding for FDE's in a normal .debug_frame section |
| 1607 | depends on the target address size. */ |
| 1608 | cie->encoding = DW_EH_PE_absptr; |
| 1609 | |
| 1610 | /* The target address size. For .eh_frame FDEs this is considered |
| 1611 | equal to the size of a target pointer. For .dwarf_frame FDEs, |
| 1612 | this is supposed to be the target address size from the associated |
| 1613 | CU header. FIXME: We do not have a good way to determine the |
| 1614 | latter. Always use the target pointer size for now. */ |
| 1615 | cie->addr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT; |
| 1616 | |
| 1617 | /* We'll determine the final value later, but we need to |
| 1618 | initialize it conservatively. */ |
| 1619 | cie->signal_frame = 0; |
| 1620 | |
| 1621 | /* Check version number. */ |
| 1622 | cie_version = read_1_byte (unit->abfd, buf); |
| 1623 | if (cie_version != 1 && cie_version != 3) |
| 1624 | return NULL; |
| 1625 | cie->version = cie_version; |
| 1626 | buf += 1; |
| 1627 | |
| 1628 | /* Interpret the interesting bits of the augmentation. */ |
| 1629 | cie->augmentation = augmentation = (char *) buf; |
| 1630 | buf += (strlen (augmentation) + 1); |
| 1631 | |
| 1632 | /* Ignore armcc augmentations. We only use them for quirks, |
| 1633 | and that doesn't happen until later. */ |
| 1634 | if (strncmp (augmentation, "armcc", 5) == 0) |
| 1635 | augmentation += strlen (augmentation); |
| 1636 | |
| 1637 | /* The GCC 2.x "eh" augmentation has a pointer immediately |
| 1638 | following the augmentation string, so it must be handled |
| 1639 | first. */ |
| 1640 | if (augmentation[0] == 'e' && augmentation[1] == 'h') |
| 1641 | { |
| 1642 | /* Skip. */ |
| 1643 | buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT; |
| 1644 | augmentation += 2; |
| 1645 | } |
| 1646 | |
| 1647 | cie->code_alignment_factor = |
| 1648 | read_unsigned_leb128 (unit->abfd, buf, &bytes_read); |
| 1649 | buf += bytes_read; |
| 1650 | |
| 1651 | cie->data_alignment_factor = |
| 1652 | read_signed_leb128 (unit->abfd, buf, &bytes_read); |
| 1653 | buf += bytes_read; |
| 1654 | |
| 1655 | if (cie_version == 1) |
| 1656 | { |
| 1657 | cie->return_address_register = read_1_byte (unit->abfd, buf); |
| 1658 | bytes_read = 1; |
| 1659 | } |
| 1660 | else |
| 1661 | cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf, |
| 1662 | &bytes_read); |
| 1663 | cie->return_address_register |
| 1664 | = dwarf2_frame_adjust_regnum (gdbarch, |
| 1665 | cie->return_address_register, |
| 1666 | eh_frame_p); |
| 1667 | |
| 1668 | buf += bytes_read; |
| 1669 | |
| 1670 | cie->saw_z_augmentation = (*augmentation == 'z'); |
| 1671 | if (cie->saw_z_augmentation) |
| 1672 | { |
| 1673 | ULONGEST length; |
| 1674 | |
| 1675 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); |
| 1676 | buf += bytes_read; |
| 1677 | if (buf > end) |
| 1678 | return NULL; |
| 1679 | cie->initial_instructions = buf + length; |
| 1680 | augmentation++; |
| 1681 | } |
| 1682 | |
| 1683 | while (*augmentation) |
| 1684 | { |
| 1685 | /* "L" indicates a byte showing how the LSDA pointer is encoded. */ |
| 1686 | if (*augmentation == 'L') |
| 1687 | { |
| 1688 | /* Skip. */ |
| 1689 | buf++; |
| 1690 | augmentation++; |
| 1691 | } |
| 1692 | |
| 1693 | /* "R" indicates a byte indicating how FDE addresses are encoded. */ |
| 1694 | else if (*augmentation == 'R') |
| 1695 | { |
| 1696 | cie->encoding = *buf++; |
| 1697 | augmentation++; |
| 1698 | } |
| 1699 | |
| 1700 | /* "P" indicates a personality routine in the CIE augmentation. */ |
| 1701 | else if (*augmentation == 'P') |
| 1702 | { |
| 1703 | /* Skip. Avoid indirection since we throw away the result. */ |
| 1704 | gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect; |
| 1705 | read_encoded_value (unit, encoding, cie->addr_size, |
| 1706 | buf, &bytes_read, 0); |
| 1707 | buf += bytes_read; |
| 1708 | augmentation++; |
| 1709 | } |
| 1710 | |
| 1711 | /* "S" indicates a signal frame, such that the return |
| 1712 | address must not be decremented to locate the call frame |
| 1713 | info for the previous frame; it might even be the first |
| 1714 | instruction of a function, so decrementing it would take |
| 1715 | us to a different function. */ |
| 1716 | else if (*augmentation == 'S') |
| 1717 | { |
| 1718 | cie->signal_frame = 1; |
| 1719 | augmentation++; |
| 1720 | } |
| 1721 | |
| 1722 | /* Otherwise we have an unknown augmentation. Assume that either |
| 1723 | there is no augmentation data, or we saw a 'z' prefix. */ |
| 1724 | else |
| 1725 | { |
| 1726 | if (cie->initial_instructions) |
| 1727 | buf = cie->initial_instructions; |
| 1728 | break; |
| 1729 | } |
| 1730 | } |
| 1731 | |
| 1732 | cie->initial_instructions = buf; |
| 1733 | cie->end = end; |
| 1734 | |
| 1735 | add_cie (unit, cie); |
| 1736 | } |
| 1737 | else |
| 1738 | { |
| 1739 | /* This is a FDE. */ |
| 1740 | struct dwarf2_fde *fde; |
| 1741 | |
| 1742 | /* In an .eh_frame section, the CIE pointer is the delta between the |
| 1743 | address within the FDE where the CIE pointer is stored and the |
| 1744 | address of the CIE. Convert it to an offset into the .eh_frame |
| 1745 | section. */ |
| 1746 | if (eh_frame_p) |
| 1747 | { |
| 1748 | cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer; |
| 1749 | cie_pointer -= (dwarf64_p ? 8 : 4); |
| 1750 | } |
| 1751 | |
| 1752 | /* In either case, validate the result is still within the section. */ |
| 1753 | if (cie_pointer >= unit->dwarf_frame_size) |
| 1754 | return NULL; |
| 1755 | |
| 1756 | fde = (struct dwarf2_fde *) |
| 1757 | obstack_alloc (&unit->objfile->objfile_obstack, |
| 1758 | sizeof (struct dwarf2_fde)); |
| 1759 | fde->cie = find_cie (unit, cie_pointer); |
| 1760 | if (fde->cie == NULL) |
| 1761 | { |
| 1762 | decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer, |
| 1763 | eh_frame_p); |
| 1764 | fde->cie = find_cie (unit, cie_pointer); |
| 1765 | } |
| 1766 | |
| 1767 | gdb_assert (fde->cie != NULL); |
| 1768 | |
| 1769 | fde->initial_location = |
| 1770 | read_encoded_value (unit, fde->cie->encoding, fde->cie->addr_size, |
| 1771 | buf, &bytes_read, 0); |
| 1772 | buf += bytes_read; |
| 1773 | |
| 1774 | fde->address_range = |
| 1775 | read_encoded_value (unit, fde->cie->encoding & 0x0f, |
| 1776 | fde->cie->addr_size, buf, &bytes_read, 0); |
| 1777 | buf += bytes_read; |
| 1778 | |
| 1779 | /* A 'z' augmentation in the CIE implies the presence of an |
| 1780 | augmentation field in the FDE as well. The only thing known |
| 1781 | to be in here at present is the LSDA entry for EH. So we |
| 1782 | can skip the whole thing. */ |
| 1783 | if (fde->cie->saw_z_augmentation) |
| 1784 | { |
| 1785 | ULONGEST length; |
| 1786 | |
| 1787 | length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read); |
| 1788 | buf += bytes_read + length; |
| 1789 | if (buf > end) |
| 1790 | return NULL; |
| 1791 | } |
| 1792 | |
| 1793 | fde->instructions = buf; |
| 1794 | fde->end = end; |
| 1795 | |
| 1796 | fde->eh_frame_p = eh_frame_p; |
| 1797 | |
| 1798 | add_fde (unit, fde); |
| 1799 | } |
| 1800 | |
| 1801 | return end; |
| 1802 | } |
| 1803 | |
| 1804 | /* Read a CIE or FDE in BUF and decode it. */ |
| 1805 | static gdb_byte * |
| 1806 | decode_frame_entry (struct comp_unit *unit, gdb_byte *start, int eh_frame_p) |
| 1807 | { |
| 1808 | enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE; |
| 1809 | gdb_byte *ret; |
| 1810 | const char *msg; |
| 1811 | ptrdiff_t start_offset; |
| 1812 | |
| 1813 | while (1) |
| 1814 | { |
| 1815 | ret = decode_frame_entry_1 (unit, start, eh_frame_p); |
| 1816 | if (ret != NULL) |
| 1817 | break; |
| 1818 | |
| 1819 | /* We have corrupt input data of some form. */ |
| 1820 | |
| 1821 | /* ??? Try, weakly, to work around compiler/assembler/linker bugs |
| 1822 | and mismatches wrt padding and alignment of debug sections. */ |
| 1823 | /* Note that there is no requirement in the standard for any |
| 1824 | alignment at all in the frame unwind sections. Testing for |
| 1825 | alignment before trying to interpret data would be incorrect. |
| 1826 | |
| 1827 | However, GCC traditionally arranged for frame sections to be |
| 1828 | sized such that the FDE length and CIE fields happen to be |
| 1829 | aligned (in theory, for performance). This, unfortunately, |
| 1830 | was done with .align directives, which had the side effect of |
| 1831 | forcing the section to be aligned by the linker. |
| 1832 | |
| 1833 | This becomes a problem when you have some other producer that |
| 1834 | creates frame sections that are not as strictly aligned. That |
| 1835 | produces a hole in the frame info that gets filled by the |
| 1836 | linker with zeros. |
| 1837 | |
| 1838 | The GCC behaviour is arguably a bug, but it's effectively now |
| 1839 | part of the ABI, so we're now stuck with it, at least at the |
| 1840 | object file level. A smart linker may decide, in the process |
| 1841 | of compressing duplicate CIE information, that it can rewrite |
| 1842 | the entire output section without this extra padding. */ |
| 1843 | |
| 1844 | start_offset = start - unit->dwarf_frame_buffer; |
| 1845 | if (workaround < ALIGN4 && (start_offset & 3) != 0) |
| 1846 | { |
| 1847 | start += 4 - (start_offset & 3); |
| 1848 | workaround = ALIGN4; |
| 1849 | continue; |
| 1850 | } |
| 1851 | if (workaround < ALIGN8 && (start_offset & 7) != 0) |
| 1852 | { |
| 1853 | start += 8 - (start_offset & 7); |
| 1854 | workaround = ALIGN8; |
| 1855 | continue; |
| 1856 | } |
| 1857 | |
| 1858 | /* Nothing left to try. Arrange to return as if we've consumed |
| 1859 | the entire input section. Hopefully we'll get valid info from |
| 1860 | the other of .debug_frame/.eh_frame. */ |
| 1861 | workaround = FAIL; |
| 1862 | ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size; |
| 1863 | break; |
| 1864 | } |
| 1865 | |
| 1866 | switch (workaround) |
| 1867 | { |
| 1868 | case NONE: |
| 1869 | break; |
| 1870 | |
| 1871 | case ALIGN4: |
| 1872 | complaint (&symfile_complaints, |
| 1873 | _("Corrupt data in %s:%s; align 4 workaround apparently succeeded"), |
| 1874 | unit->dwarf_frame_section->owner->filename, |
| 1875 | unit->dwarf_frame_section->name); |
| 1876 | break; |
| 1877 | |
| 1878 | case ALIGN8: |
| 1879 | complaint (&symfile_complaints, |
| 1880 | _("Corrupt data in %s:%s; align 8 workaround apparently succeeded"), |
| 1881 | unit->dwarf_frame_section->owner->filename, |
| 1882 | unit->dwarf_frame_section->name); |
| 1883 | break; |
| 1884 | |
| 1885 | default: |
| 1886 | complaint (&symfile_complaints, |
| 1887 | _("Corrupt data in %s:%s"), |
| 1888 | unit->dwarf_frame_section->owner->filename, |
| 1889 | unit->dwarf_frame_section->name); |
| 1890 | break; |
| 1891 | } |
| 1892 | |
| 1893 | return ret; |
| 1894 | } |
| 1895 | \f |
| 1896 | |
| 1897 | /* FIXME: kettenis/20030504: This still needs to be integrated with |
| 1898 | dwarf2read.c in a better way. */ |
| 1899 | |
| 1900 | /* Imported from dwarf2read.c. */ |
| 1901 | extern asection *dwarf_frame_section; |
| 1902 | extern asection *dwarf_eh_frame_section; |
| 1903 | |
| 1904 | /* Imported from dwarf2read.c. */ |
| 1905 | extern gdb_byte *dwarf2_read_section (struct objfile *objfile, asection *sectp); |
| 1906 | |
| 1907 | void |
| 1908 | dwarf2_build_frame_info (struct objfile *objfile) |
| 1909 | { |
| 1910 | struct comp_unit *unit; |
| 1911 | gdb_byte *frame_ptr; |
| 1912 | |
| 1913 | /* Build a minimal decoding of the DWARF2 compilation unit. */ |
| 1914 | unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack, |
| 1915 | sizeof (struct comp_unit)); |
| 1916 | unit->abfd = objfile->obfd; |
| 1917 | unit->objfile = objfile; |
| 1918 | unit->dbase = 0; |
| 1919 | unit->tbase = 0; |
| 1920 | |
| 1921 | /* First add the information from the .eh_frame section. That way, |
| 1922 | the FDEs from that section are searched last. */ |
| 1923 | if (dwarf_eh_frame_section) |
| 1924 | { |
| 1925 | asection *got, *txt; |
| 1926 | |
| 1927 | unit->cie = NULL; |
| 1928 | unit->dwarf_frame_buffer = dwarf2_read_section (objfile, |
| 1929 | dwarf_eh_frame_section); |
| 1930 | |
| 1931 | unit->dwarf_frame_size = bfd_get_section_size (dwarf_eh_frame_section); |
| 1932 | unit->dwarf_frame_section = dwarf_eh_frame_section; |
| 1933 | |
| 1934 | /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base |
| 1935 | that is used for the i386/amd64 target, which currently is |
| 1936 | the only target in GCC that supports/uses the |
| 1937 | DW_EH_PE_datarel encoding. */ |
| 1938 | got = bfd_get_section_by_name (unit->abfd, ".got"); |
| 1939 | if (got) |
| 1940 | unit->dbase = got->vma; |
| 1941 | |
| 1942 | /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64 |
| 1943 | so far. */ |
| 1944 | txt = bfd_get_section_by_name (unit->abfd, ".text"); |
| 1945 | if (txt) |
| 1946 | unit->tbase = txt->vma; |
| 1947 | |
| 1948 | frame_ptr = unit->dwarf_frame_buffer; |
| 1949 | while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 1950 | frame_ptr = decode_frame_entry (unit, frame_ptr, 1); |
| 1951 | } |
| 1952 | |
| 1953 | if (dwarf_frame_section) |
| 1954 | { |
| 1955 | unit->cie = NULL; |
| 1956 | unit->dwarf_frame_buffer = dwarf2_read_section (objfile, |
| 1957 | dwarf_frame_section); |
| 1958 | unit->dwarf_frame_size = bfd_get_section_size (dwarf_frame_section); |
| 1959 | unit->dwarf_frame_section = dwarf_frame_section; |
| 1960 | |
| 1961 | frame_ptr = unit->dwarf_frame_buffer; |
| 1962 | while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 1963 | frame_ptr = decode_frame_entry (unit, frame_ptr, 0); |
| 1964 | } |
| 1965 | } |
| 1966 | |
| 1967 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 1968 | void _initialize_dwarf2_frame (void); |
| 1969 | |
| 1970 | void |
| 1971 | _initialize_dwarf2_frame (void) |
| 1972 | { |
| 1973 | dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init); |
| 1974 | dwarf2_frame_objfile_data = register_objfile_data (); |
| 1975 | } |