| 1 | /* Frame unwinder for frames with DWARF Call Frame Information. |
| 2 | |
| 3 | Copyright (C) 2003-2013 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 "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 | #include "ax.h" |
| 41 | #include "dwarf2loc.h" |
| 42 | #include "exceptions.h" |
| 43 | #include "dwarf2-frame-tailcall.h" |
| 44 | |
| 45 | struct comp_unit; |
| 46 | |
| 47 | /* Call Frame Information (CFI). */ |
| 48 | |
| 49 | /* Common Information Entry (CIE). */ |
| 50 | |
| 51 | struct dwarf2_cie |
| 52 | { |
| 53 | /* Computation Unit for this CIE. */ |
| 54 | struct comp_unit *unit; |
| 55 | |
| 56 | /* Offset into the .debug_frame section where this CIE was found. |
| 57 | Used to identify this CIE. */ |
| 58 | ULONGEST cie_pointer; |
| 59 | |
| 60 | /* Constant that is factored out of all advance location |
| 61 | instructions. */ |
| 62 | ULONGEST code_alignment_factor; |
| 63 | |
| 64 | /* Constants that is factored out of all offset instructions. */ |
| 65 | LONGEST data_alignment_factor; |
| 66 | |
| 67 | /* Return address column. */ |
| 68 | ULONGEST return_address_register; |
| 69 | |
| 70 | /* Instruction sequence to initialize a register set. */ |
| 71 | const gdb_byte *initial_instructions; |
| 72 | const gdb_byte *end; |
| 73 | |
| 74 | /* Saved augmentation, in case it's needed later. */ |
| 75 | char *augmentation; |
| 76 | |
| 77 | /* Encoding of addresses. */ |
| 78 | gdb_byte encoding; |
| 79 | |
| 80 | /* Target address size in bytes. */ |
| 81 | int addr_size; |
| 82 | |
| 83 | /* Target pointer size in bytes. */ |
| 84 | int ptr_size; |
| 85 | |
| 86 | /* True if a 'z' augmentation existed. */ |
| 87 | unsigned char saw_z_augmentation; |
| 88 | |
| 89 | /* True if an 'S' augmentation existed. */ |
| 90 | unsigned char signal_frame; |
| 91 | |
| 92 | /* The version recorded in the CIE. */ |
| 93 | unsigned char version; |
| 94 | |
| 95 | /* The segment size. */ |
| 96 | unsigned char segment_size; |
| 97 | }; |
| 98 | |
| 99 | struct dwarf2_cie_table |
| 100 | { |
| 101 | int num_entries; |
| 102 | struct dwarf2_cie **entries; |
| 103 | }; |
| 104 | |
| 105 | /* Frame Description Entry (FDE). */ |
| 106 | |
| 107 | struct dwarf2_fde |
| 108 | { |
| 109 | /* CIE for this FDE. */ |
| 110 | struct dwarf2_cie *cie; |
| 111 | |
| 112 | /* First location associated with this FDE. */ |
| 113 | CORE_ADDR initial_location; |
| 114 | |
| 115 | /* Number of bytes of program instructions described by this FDE. */ |
| 116 | CORE_ADDR address_range; |
| 117 | |
| 118 | /* Instruction sequence. */ |
| 119 | const gdb_byte *instructions; |
| 120 | const gdb_byte *end; |
| 121 | |
| 122 | /* True if this FDE is read from a .eh_frame instead of a .debug_frame |
| 123 | section. */ |
| 124 | unsigned char eh_frame_p; |
| 125 | }; |
| 126 | |
| 127 | struct dwarf2_fde_table |
| 128 | { |
| 129 | int num_entries; |
| 130 | struct dwarf2_fde **entries; |
| 131 | }; |
| 132 | |
| 133 | /* A minimal decoding of DWARF2 compilation units. We only decode |
| 134 | what's needed to get to the call frame information. */ |
| 135 | |
| 136 | struct comp_unit |
| 137 | { |
| 138 | /* Keep the bfd convenient. */ |
| 139 | bfd *abfd; |
| 140 | |
| 141 | struct objfile *objfile; |
| 142 | |
| 143 | /* Pointer to the .debug_frame section loaded into memory. */ |
| 144 | gdb_byte *dwarf_frame_buffer; |
| 145 | |
| 146 | /* Length of the loaded .debug_frame section. */ |
| 147 | bfd_size_type dwarf_frame_size; |
| 148 | |
| 149 | /* Pointer to the .debug_frame section. */ |
| 150 | asection *dwarf_frame_section; |
| 151 | |
| 152 | /* Base for DW_EH_PE_datarel encodings. */ |
| 153 | bfd_vma dbase; |
| 154 | |
| 155 | /* Base for DW_EH_PE_textrel encodings. */ |
| 156 | bfd_vma tbase; |
| 157 | }; |
| 158 | |
| 159 | static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc, |
| 160 | CORE_ADDR *out_offset); |
| 161 | |
| 162 | static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum, |
| 163 | int eh_frame_p); |
| 164 | |
| 165 | static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding, |
| 166 | int ptr_len, const gdb_byte *buf, |
| 167 | unsigned int *bytes_read_ptr, |
| 168 | CORE_ADDR func_base); |
| 169 | \f |
| 170 | |
| 171 | /* Structure describing a frame state. */ |
| 172 | |
| 173 | struct dwarf2_frame_state |
| 174 | { |
| 175 | /* Each register save state can be described in terms of a CFA slot, |
| 176 | another register, or a location expression. */ |
| 177 | struct dwarf2_frame_state_reg_info |
| 178 | { |
| 179 | struct dwarf2_frame_state_reg *reg; |
| 180 | int num_regs; |
| 181 | |
| 182 | LONGEST cfa_offset; |
| 183 | ULONGEST cfa_reg; |
| 184 | enum { |
| 185 | CFA_UNSET, |
| 186 | CFA_REG_OFFSET, |
| 187 | CFA_EXP |
| 188 | } cfa_how; |
| 189 | const gdb_byte *cfa_exp; |
| 190 | |
| 191 | /* Used to implement DW_CFA_remember_state. */ |
| 192 | struct dwarf2_frame_state_reg_info *prev; |
| 193 | } regs; |
| 194 | |
| 195 | /* The PC described by the current frame state. */ |
| 196 | CORE_ADDR pc; |
| 197 | |
| 198 | /* Initial register set from the CIE. |
| 199 | Used to implement DW_CFA_restore. */ |
| 200 | struct dwarf2_frame_state_reg_info initial; |
| 201 | |
| 202 | /* The information we care about from the CIE. */ |
| 203 | LONGEST data_align; |
| 204 | ULONGEST code_align; |
| 205 | ULONGEST retaddr_column; |
| 206 | |
| 207 | /* Flags for known producer quirks. */ |
| 208 | |
| 209 | /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa |
| 210 | and DW_CFA_def_cfa_offset takes a factored offset. */ |
| 211 | int armcc_cfa_offsets_sf; |
| 212 | |
| 213 | /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that |
| 214 | the CFA is defined as REG - OFFSET rather than REG + OFFSET. */ |
| 215 | int armcc_cfa_offsets_reversed; |
| 216 | }; |
| 217 | |
| 218 | /* Store the length the expression for the CFA in the `cfa_reg' field, |
| 219 | which is unused in that case. */ |
| 220 | #define cfa_exp_len cfa_reg |
| 221 | |
| 222 | /* Assert that the register set RS is large enough to store gdbarch_num_regs |
| 223 | columns. If necessary, enlarge the register set. */ |
| 224 | |
| 225 | static void |
| 226 | dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs, |
| 227 | int num_regs) |
| 228 | { |
| 229 | size_t size = sizeof (struct dwarf2_frame_state_reg); |
| 230 | |
| 231 | if (num_regs <= rs->num_regs) |
| 232 | return; |
| 233 | |
| 234 | rs->reg = (struct dwarf2_frame_state_reg *) |
| 235 | xrealloc (rs->reg, num_regs * size); |
| 236 | |
| 237 | /* Initialize newly allocated registers. */ |
| 238 | memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size); |
| 239 | rs->num_regs = num_regs; |
| 240 | } |
| 241 | |
| 242 | /* Copy the register columns in register set RS into newly allocated |
| 243 | memory and return a pointer to this newly created copy. */ |
| 244 | |
| 245 | static struct dwarf2_frame_state_reg * |
| 246 | dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs) |
| 247 | { |
| 248 | size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg); |
| 249 | struct dwarf2_frame_state_reg *reg; |
| 250 | |
| 251 | reg = (struct dwarf2_frame_state_reg *) xmalloc (size); |
| 252 | memcpy (reg, rs->reg, size); |
| 253 | |
| 254 | return reg; |
| 255 | } |
| 256 | |
| 257 | /* Release the memory allocated to register set RS. */ |
| 258 | |
| 259 | static void |
| 260 | dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs) |
| 261 | { |
| 262 | if (rs) |
| 263 | { |
| 264 | dwarf2_frame_state_free_regs (rs->prev); |
| 265 | |
| 266 | xfree (rs->reg); |
| 267 | xfree (rs); |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | /* Release the memory allocated to the frame state FS. */ |
| 272 | |
| 273 | static void |
| 274 | dwarf2_frame_state_free (void *p) |
| 275 | { |
| 276 | struct dwarf2_frame_state *fs = p; |
| 277 | |
| 278 | dwarf2_frame_state_free_regs (fs->initial.prev); |
| 279 | dwarf2_frame_state_free_regs (fs->regs.prev); |
| 280 | xfree (fs->initial.reg); |
| 281 | xfree (fs->regs.reg); |
| 282 | xfree (fs); |
| 283 | } |
| 284 | \f |
| 285 | |
| 286 | /* Helper functions for execute_stack_op. */ |
| 287 | |
| 288 | static CORE_ADDR |
| 289 | read_reg (void *baton, int reg) |
| 290 | { |
| 291 | struct frame_info *this_frame = (struct frame_info *) baton; |
| 292 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 293 | int regnum; |
| 294 | gdb_byte *buf; |
| 295 | |
| 296 | regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); |
| 297 | |
| 298 | buf = alloca (register_size (gdbarch, regnum)); |
| 299 | get_frame_register (this_frame, regnum, buf); |
| 300 | |
| 301 | /* Convert the register to an integer. This returns a LONGEST |
| 302 | rather than a CORE_ADDR, but unpack_pointer does the same thing |
| 303 | under the covers, and this makes more sense for non-pointer |
| 304 | registers. Maybe read_reg and the associated interfaces should |
| 305 | deal with "struct value" instead of CORE_ADDR. */ |
| 306 | return unpack_long (register_type (gdbarch, regnum), buf); |
| 307 | } |
| 308 | |
| 309 | static void |
| 310 | read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
| 311 | { |
| 312 | read_memory (addr, buf, len); |
| 313 | } |
| 314 | |
| 315 | /* Execute the required actions for both the DW_CFA_restore and |
| 316 | DW_CFA_restore_extended instructions. */ |
| 317 | static void |
| 318 | dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num, |
| 319 | struct dwarf2_frame_state *fs, int eh_frame_p) |
| 320 | { |
| 321 | ULONGEST reg; |
| 322 | |
| 323 | gdb_assert (fs->initial.reg); |
| 324 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p); |
| 325 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 326 | |
| 327 | /* Check if this register was explicitly initialized in the |
| 328 | CIE initial instructions. If not, default the rule to |
| 329 | UNSPECIFIED. */ |
| 330 | if (reg < fs->initial.num_regs) |
| 331 | fs->regs.reg[reg] = fs->initial.reg[reg]; |
| 332 | else |
| 333 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED; |
| 334 | |
| 335 | if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 336 | complaint (&symfile_complaints, _("\ |
| 337 | incomplete CFI data; DW_CFA_restore unspecified\n\ |
| 338 | register %s (#%d) at %s"), |
| 339 | gdbarch_register_name |
| 340 | (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)), |
| 341 | gdbarch_dwarf2_reg_to_regnum (gdbarch, reg), |
| 342 | paddress (gdbarch, fs->pc)); |
| 343 | } |
| 344 | |
| 345 | /* Virtual method table for execute_stack_op below. */ |
| 346 | |
| 347 | static const struct dwarf_expr_context_funcs dwarf2_frame_ctx_funcs = |
| 348 | { |
| 349 | read_reg, |
| 350 | read_mem, |
| 351 | ctx_no_get_frame_base, |
| 352 | ctx_no_get_frame_cfa, |
| 353 | ctx_no_get_frame_pc, |
| 354 | ctx_no_get_tls_address, |
| 355 | ctx_no_dwarf_call, |
| 356 | ctx_no_get_base_type, |
| 357 | ctx_no_push_dwarf_reg_entry_value, |
| 358 | ctx_no_get_addr_index |
| 359 | }; |
| 360 | |
| 361 | static CORE_ADDR |
| 362 | execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size, |
| 363 | CORE_ADDR offset, struct frame_info *this_frame, |
| 364 | CORE_ADDR initial, int initial_in_stack_memory) |
| 365 | { |
| 366 | struct dwarf_expr_context *ctx; |
| 367 | CORE_ADDR result; |
| 368 | struct cleanup *old_chain; |
| 369 | |
| 370 | ctx = new_dwarf_expr_context (); |
| 371 | old_chain = make_cleanup_free_dwarf_expr_context (ctx); |
| 372 | make_cleanup_value_free_to_mark (value_mark ()); |
| 373 | |
| 374 | ctx->gdbarch = get_frame_arch (this_frame); |
| 375 | ctx->addr_size = addr_size; |
| 376 | ctx->ref_addr_size = -1; |
| 377 | ctx->offset = offset; |
| 378 | ctx->baton = this_frame; |
| 379 | ctx->funcs = &dwarf2_frame_ctx_funcs; |
| 380 | |
| 381 | dwarf_expr_push_address (ctx, initial, initial_in_stack_memory); |
| 382 | dwarf_expr_eval (ctx, exp, len); |
| 383 | |
| 384 | if (ctx->location == DWARF_VALUE_MEMORY) |
| 385 | result = dwarf_expr_fetch_address (ctx, 0); |
| 386 | else if (ctx->location == DWARF_VALUE_REGISTER) |
| 387 | result = read_reg (this_frame, value_as_long (dwarf_expr_fetch (ctx, 0))); |
| 388 | else |
| 389 | { |
| 390 | /* This is actually invalid DWARF, but if we ever do run across |
| 391 | it somehow, we might as well support it. So, instead, report |
| 392 | it as unimplemented. */ |
| 393 | error (_("\ |
| 394 | Not implemented: computing unwound register using explicit value operator")); |
| 395 | } |
| 396 | |
| 397 | do_cleanups (old_chain); |
| 398 | |
| 399 | return result; |
| 400 | } |
| 401 | \f |
| 402 | |
| 403 | /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior |
| 404 | PC. Modify FS state accordingly. Return current INSN_PTR where the |
| 405 | execution has stopped, one can resume it on the next call. */ |
| 406 | |
| 407 | static const gdb_byte * |
| 408 | execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr, |
| 409 | const gdb_byte *insn_end, struct gdbarch *gdbarch, |
| 410 | CORE_ADDR pc, struct dwarf2_frame_state *fs) |
| 411 | { |
| 412 | int eh_frame_p = fde->eh_frame_p; |
| 413 | int bytes_read; |
| 414 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 415 | |
| 416 | while (insn_ptr < insn_end && fs->pc <= pc) |
| 417 | { |
| 418 | gdb_byte insn = *insn_ptr++; |
| 419 | uint64_t utmp, reg; |
| 420 | int64_t offset; |
| 421 | |
| 422 | if ((insn & 0xc0) == DW_CFA_advance_loc) |
| 423 | fs->pc += (insn & 0x3f) * fs->code_align; |
| 424 | else if ((insn & 0xc0) == DW_CFA_offset) |
| 425 | { |
| 426 | reg = insn & 0x3f; |
| 427 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 428 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 429 | offset = utmp * fs->data_align; |
| 430 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 431 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 432 | fs->regs.reg[reg].loc.offset = offset; |
| 433 | } |
| 434 | else if ((insn & 0xc0) == DW_CFA_restore) |
| 435 | { |
| 436 | reg = insn & 0x3f; |
| 437 | dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p); |
| 438 | } |
| 439 | else |
| 440 | { |
| 441 | switch (insn) |
| 442 | { |
| 443 | case DW_CFA_set_loc: |
| 444 | fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding, |
| 445 | fde->cie->ptr_size, insn_ptr, |
| 446 | &bytes_read, fde->initial_location); |
| 447 | /* Apply the objfile offset for relocatable objects. */ |
| 448 | fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets, |
| 449 | SECT_OFF_TEXT (fde->cie->unit->objfile)); |
| 450 | insn_ptr += bytes_read; |
| 451 | break; |
| 452 | |
| 453 | case DW_CFA_advance_loc1: |
| 454 | utmp = extract_unsigned_integer (insn_ptr, 1, byte_order); |
| 455 | fs->pc += utmp * fs->code_align; |
| 456 | insn_ptr++; |
| 457 | break; |
| 458 | case DW_CFA_advance_loc2: |
| 459 | utmp = extract_unsigned_integer (insn_ptr, 2, byte_order); |
| 460 | fs->pc += utmp * fs->code_align; |
| 461 | insn_ptr += 2; |
| 462 | break; |
| 463 | case DW_CFA_advance_loc4: |
| 464 | utmp = extract_unsigned_integer (insn_ptr, 4, byte_order); |
| 465 | fs->pc += utmp * fs->code_align; |
| 466 | insn_ptr += 4; |
| 467 | break; |
| 468 | |
| 469 | case DW_CFA_offset_extended: |
| 470 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 471 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 472 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 473 | offset = utmp * fs->data_align; |
| 474 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 475 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 476 | fs->regs.reg[reg].loc.offset = offset; |
| 477 | break; |
| 478 | |
| 479 | case DW_CFA_restore_extended: |
| 480 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 481 | dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p); |
| 482 | break; |
| 483 | |
| 484 | case DW_CFA_undefined: |
| 485 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 486 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 487 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 488 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED; |
| 489 | break; |
| 490 | |
| 491 | case DW_CFA_same_value: |
| 492 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 493 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 494 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 495 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE; |
| 496 | break; |
| 497 | |
| 498 | case DW_CFA_register: |
| 499 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 500 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 501 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 502 | utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p); |
| 503 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 504 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; |
| 505 | fs->regs.reg[reg].loc.reg = utmp; |
| 506 | break; |
| 507 | |
| 508 | case DW_CFA_remember_state: |
| 509 | { |
| 510 | struct dwarf2_frame_state_reg_info *new_rs; |
| 511 | |
| 512 | new_rs = XMALLOC (struct dwarf2_frame_state_reg_info); |
| 513 | *new_rs = fs->regs; |
| 514 | fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs); |
| 515 | fs->regs.prev = new_rs; |
| 516 | } |
| 517 | break; |
| 518 | |
| 519 | case DW_CFA_restore_state: |
| 520 | { |
| 521 | struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev; |
| 522 | |
| 523 | if (old_rs == NULL) |
| 524 | { |
| 525 | complaint (&symfile_complaints, _("\ |
| 526 | bad CFI data; mismatched DW_CFA_restore_state at %s"), |
| 527 | paddress (gdbarch, fs->pc)); |
| 528 | } |
| 529 | else |
| 530 | { |
| 531 | xfree (fs->regs.reg); |
| 532 | fs->regs = *old_rs; |
| 533 | xfree (old_rs); |
| 534 | } |
| 535 | } |
| 536 | break; |
| 537 | |
| 538 | case DW_CFA_def_cfa: |
| 539 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 540 | fs->regs.cfa_reg = reg; |
| 541 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 542 | |
| 543 | if (fs->armcc_cfa_offsets_sf) |
| 544 | utmp *= fs->data_align; |
| 545 | |
| 546 | fs->regs.cfa_offset = utmp; |
| 547 | fs->regs.cfa_how = CFA_REG_OFFSET; |
| 548 | break; |
| 549 | |
| 550 | case DW_CFA_def_cfa_register: |
| 551 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 552 | fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg, |
| 553 | eh_frame_p); |
| 554 | fs->regs.cfa_how = CFA_REG_OFFSET; |
| 555 | break; |
| 556 | |
| 557 | case DW_CFA_def_cfa_offset: |
| 558 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 559 | |
| 560 | if (fs->armcc_cfa_offsets_sf) |
| 561 | utmp *= fs->data_align; |
| 562 | |
| 563 | fs->regs.cfa_offset = utmp; |
| 564 | /* cfa_how deliberately not set. */ |
| 565 | break; |
| 566 | |
| 567 | case DW_CFA_nop: |
| 568 | break; |
| 569 | |
| 570 | case DW_CFA_def_cfa_expression: |
| 571 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 572 | fs->regs.cfa_exp_len = utmp; |
| 573 | fs->regs.cfa_exp = insn_ptr; |
| 574 | fs->regs.cfa_how = CFA_EXP; |
| 575 | insn_ptr += fs->regs.cfa_exp_len; |
| 576 | break; |
| 577 | |
| 578 | case DW_CFA_expression: |
| 579 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 580 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 581 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 582 | insn_ptr = safe_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_EXP; |
| 586 | insn_ptr += utmp; |
| 587 | break; |
| 588 | |
| 589 | case DW_CFA_offset_extended_sf: |
| 590 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 591 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 592 | insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset); |
| 593 | offset *= fs->data_align; |
| 594 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 595 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 596 | fs->regs.reg[reg].loc.offset = offset; |
| 597 | break; |
| 598 | |
| 599 | case DW_CFA_val_offset: |
| 600 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 601 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 602 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 603 | offset = utmp * fs->data_align; |
| 604 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET; |
| 605 | fs->regs.reg[reg].loc.offset = offset; |
| 606 | break; |
| 607 | |
| 608 | case DW_CFA_val_offset_sf: |
| 609 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 610 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 611 | insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset); |
| 612 | offset *= fs->data_align; |
| 613 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET; |
| 614 | fs->regs.reg[reg].loc.offset = offset; |
| 615 | break; |
| 616 | |
| 617 | case DW_CFA_val_expression: |
| 618 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 619 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 620 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 621 | fs->regs.reg[reg].loc.exp = insn_ptr; |
| 622 | fs->regs.reg[reg].exp_len = utmp; |
| 623 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP; |
| 624 | insn_ptr += utmp; |
| 625 | break; |
| 626 | |
| 627 | case DW_CFA_def_cfa_sf: |
| 628 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 629 | fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg, |
| 630 | eh_frame_p); |
| 631 | insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset); |
| 632 | fs->regs.cfa_offset = offset * fs->data_align; |
| 633 | fs->regs.cfa_how = CFA_REG_OFFSET; |
| 634 | break; |
| 635 | |
| 636 | case DW_CFA_def_cfa_offset_sf: |
| 637 | insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset); |
| 638 | fs->regs.cfa_offset = offset * fs->data_align; |
| 639 | /* cfa_how deliberately not set. */ |
| 640 | break; |
| 641 | |
| 642 | case DW_CFA_GNU_window_save: |
| 643 | /* This is SPARC-specific code, and contains hard-coded |
| 644 | constants for the register numbering scheme used by |
| 645 | GCC. Rather than having a architecture-specific |
| 646 | operation that's only ever used by a single |
| 647 | architecture, we provide the implementation here. |
| 648 | Incidentally that's what GCC does too in its |
| 649 | unwinder. */ |
| 650 | { |
| 651 | int size = register_size (gdbarch, 0); |
| 652 | |
| 653 | dwarf2_frame_state_alloc_regs (&fs->regs, 32); |
| 654 | for (reg = 8; reg < 16; reg++) |
| 655 | { |
| 656 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; |
| 657 | fs->regs.reg[reg].loc.reg = reg + 16; |
| 658 | } |
| 659 | for (reg = 16; reg < 32; reg++) |
| 660 | { |
| 661 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 662 | fs->regs.reg[reg].loc.offset = (reg - 16) * size; |
| 663 | } |
| 664 | } |
| 665 | break; |
| 666 | |
| 667 | case DW_CFA_GNU_args_size: |
| 668 | /* Ignored. */ |
| 669 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 670 | break; |
| 671 | |
| 672 | case DW_CFA_GNU_negative_offset_extended: |
| 673 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 674 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 675 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &offset); |
| 676 | offset *= fs->data_align; |
| 677 | dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| 678 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 679 | fs->regs.reg[reg].loc.offset = -offset; |
| 680 | break; |
| 681 | |
| 682 | default: |
| 683 | internal_error (__FILE__, __LINE__, |
| 684 | _("Unknown CFI encountered.")); |
| 685 | } |
| 686 | } |
| 687 | } |
| 688 | |
| 689 | if (fs->initial.reg == NULL) |
| 690 | { |
| 691 | /* Don't allow remember/restore between CIE and FDE programs. */ |
| 692 | dwarf2_frame_state_free_regs (fs->regs.prev); |
| 693 | fs->regs.prev = NULL; |
| 694 | } |
| 695 | |
| 696 | return insn_ptr; |
| 697 | } |
| 698 | \f |
| 699 | |
| 700 | /* Architecture-specific operations. */ |
| 701 | |
| 702 | /* Per-architecture data key. */ |
| 703 | static struct gdbarch_data *dwarf2_frame_data; |
| 704 | |
| 705 | struct dwarf2_frame_ops |
| 706 | { |
| 707 | /* Pre-initialize the register state REG for register REGNUM. */ |
| 708 | void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *, |
| 709 | struct frame_info *); |
| 710 | |
| 711 | /* Check whether the THIS_FRAME is a signal trampoline. */ |
| 712 | int (*signal_frame_p) (struct gdbarch *, struct frame_info *); |
| 713 | |
| 714 | /* Convert .eh_frame register number to DWARF register number, or |
| 715 | adjust .debug_frame register number. */ |
| 716 | int (*adjust_regnum) (struct gdbarch *, int, int); |
| 717 | }; |
| 718 | |
| 719 | /* Default architecture-specific register state initialization |
| 720 | function. */ |
| 721 | |
| 722 | static void |
| 723 | dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum, |
| 724 | struct dwarf2_frame_state_reg *reg, |
| 725 | struct frame_info *this_frame) |
| 726 | { |
| 727 | /* If we have a register that acts as a program counter, mark it as |
| 728 | a destination for the return address. If we have a register that |
| 729 | serves as the stack pointer, arrange for it to be filled with the |
| 730 | call frame address (CFA). The other registers are marked as |
| 731 | unspecified. |
| 732 | |
| 733 | We copy the return address to the program counter, since many |
| 734 | parts in GDB assume that it is possible to get the return address |
| 735 | by unwinding the program counter register. However, on ISA's |
| 736 | with a dedicated return address register, the CFI usually only |
| 737 | contains information to unwind that return address register. |
| 738 | |
| 739 | The reason we're treating the stack pointer special here is |
| 740 | because in many cases GCC doesn't emit CFI for the stack pointer |
| 741 | and implicitly assumes that it is equal to the CFA. This makes |
| 742 | some sense since the DWARF specification (version 3, draft 8, |
| 743 | p. 102) says that: |
| 744 | |
| 745 | "Typically, the CFA is defined to be the value of the stack |
| 746 | pointer at the call site in the previous frame (which may be |
| 747 | different from its value on entry to the current frame)." |
| 748 | |
| 749 | However, this isn't true for all platforms supported by GCC |
| 750 | (e.g. IBM S/390 and zSeries). Those architectures should provide |
| 751 | their own architecture-specific initialization function. */ |
| 752 | |
| 753 | if (regnum == gdbarch_pc_regnum (gdbarch)) |
| 754 | reg->how = DWARF2_FRAME_REG_RA; |
| 755 | else if (regnum == gdbarch_sp_regnum (gdbarch)) |
| 756 | reg->how = DWARF2_FRAME_REG_CFA; |
| 757 | } |
| 758 | |
| 759 | /* Return a default for the architecture-specific operations. */ |
| 760 | |
| 761 | static void * |
| 762 | dwarf2_frame_init (struct obstack *obstack) |
| 763 | { |
| 764 | struct dwarf2_frame_ops *ops; |
| 765 | |
| 766 | ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops); |
| 767 | ops->init_reg = dwarf2_frame_default_init_reg; |
| 768 | return ops; |
| 769 | } |
| 770 | |
| 771 | /* Set the architecture-specific register state initialization |
| 772 | function for GDBARCH to INIT_REG. */ |
| 773 | |
| 774 | void |
| 775 | dwarf2_frame_set_init_reg (struct gdbarch *gdbarch, |
| 776 | void (*init_reg) (struct gdbarch *, int, |
| 777 | struct dwarf2_frame_state_reg *, |
| 778 | struct frame_info *)) |
| 779 | { |
| 780 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 781 | |
| 782 | ops->init_reg = init_reg; |
| 783 | } |
| 784 | |
| 785 | /* Pre-initialize the register state REG for register REGNUM. */ |
| 786 | |
| 787 | static void |
| 788 | dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum, |
| 789 | struct dwarf2_frame_state_reg *reg, |
| 790 | struct frame_info *this_frame) |
| 791 | { |
| 792 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 793 | |
| 794 | ops->init_reg (gdbarch, regnum, reg, this_frame); |
| 795 | } |
| 796 | |
| 797 | /* Set the architecture-specific signal trampoline recognition |
| 798 | function for GDBARCH to SIGNAL_FRAME_P. */ |
| 799 | |
| 800 | void |
| 801 | dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch, |
| 802 | int (*signal_frame_p) (struct gdbarch *, |
| 803 | struct frame_info *)) |
| 804 | { |
| 805 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 806 | |
| 807 | ops->signal_frame_p = signal_frame_p; |
| 808 | } |
| 809 | |
| 810 | /* Query the architecture-specific signal frame recognizer for |
| 811 | THIS_FRAME. */ |
| 812 | |
| 813 | static int |
| 814 | dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch, |
| 815 | struct frame_info *this_frame) |
| 816 | { |
| 817 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 818 | |
| 819 | if (ops->signal_frame_p == NULL) |
| 820 | return 0; |
| 821 | return ops->signal_frame_p (gdbarch, this_frame); |
| 822 | } |
| 823 | |
| 824 | /* Set the architecture-specific adjustment of .eh_frame and .debug_frame |
| 825 | register numbers. */ |
| 826 | |
| 827 | void |
| 828 | dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch, |
| 829 | int (*adjust_regnum) (struct gdbarch *, |
| 830 | int, int)) |
| 831 | { |
| 832 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 833 | |
| 834 | ops->adjust_regnum = adjust_regnum; |
| 835 | } |
| 836 | |
| 837 | /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame |
| 838 | register. */ |
| 839 | |
| 840 | static int |
| 841 | dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, |
| 842 | int regnum, int eh_frame_p) |
| 843 | { |
| 844 | struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| 845 | |
| 846 | if (ops->adjust_regnum == NULL) |
| 847 | return regnum; |
| 848 | return ops->adjust_regnum (gdbarch, regnum, eh_frame_p); |
| 849 | } |
| 850 | |
| 851 | static void |
| 852 | dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs, |
| 853 | struct dwarf2_fde *fde) |
| 854 | { |
| 855 | struct symtab *s; |
| 856 | |
| 857 | s = find_pc_symtab (fs->pc); |
| 858 | if (s == NULL) |
| 859 | return; |
| 860 | |
| 861 | if (producer_is_realview (s->producer)) |
| 862 | { |
| 863 | if (fde->cie->version == 1) |
| 864 | fs->armcc_cfa_offsets_sf = 1; |
| 865 | |
| 866 | if (fde->cie->version == 1) |
| 867 | fs->armcc_cfa_offsets_reversed = 1; |
| 868 | |
| 869 | /* The reversed offset problem is present in some compilers |
| 870 | using DWARF3, but it was eventually fixed. Check the ARM |
| 871 | defined augmentations, which are in the format "armcc" followed |
| 872 | by a list of one-character options. The "+" option means |
| 873 | this problem is fixed (no quirk needed). If the armcc |
| 874 | augmentation is missing, the quirk is needed. */ |
| 875 | if (fde->cie->version == 3 |
| 876 | && (strncmp (fde->cie->augmentation, "armcc", 5) != 0 |
| 877 | || strchr (fde->cie->augmentation + 5, '+') == NULL)) |
| 878 | fs->armcc_cfa_offsets_reversed = 1; |
| 879 | |
| 880 | return; |
| 881 | } |
| 882 | } |
| 883 | \f |
| 884 | |
| 885 | void |
| 886 | dwarf2_compile_cfa_to_ax (struct agent_expr *expr, struct axs_value *loc, |
| 887 | struct gdbarch *gdbarch, |
| 888 | CORE_ADDR pc, |
| 889 | struct dwarf2_per_cu_data *data) |
| 890 | { |
| 891 | struct dwarf2_fde *fde; |
| 892 | CORE_ADDR text_offset; |
| 893 | struct dwarf2_frame_state fs; |
| 894 | int addr_size; |
| 895 | |
| 896 | memset (&fs, 0, sizeof (struct dwarf2_frame_state)); |
| 897 | |
| 898 | fs.pc = pc; |
| 899 | |
| 900 | /* Find the correct FDE. */ |
| 901 | fde = dwarf2_frame_find_fde (&fs.pc, &text_offset); |
| 902 | if (fde == NULL) |
| 903 | error (_("Could not compute CFA; needed to translate this expression")); |
| 904 | |
| 905 | /* Extract any interesting information from the CIE. */ |
| 906 | fs.data_align = fde->cie->data_alignment_factor; |
| 907 | fs.code_align = fde->cie->code_alignment_factor; |
| 908 | fs.retaddr_column = fde->cie->return_address_register; |
| 909 | addr_size = fde->cie->addr_size; |
| 910 | |
| 911 | /* Check for "quirks" - known bugs in producers. */ |
| 912 | dwarf2_frame_find_quirks (&fs, fde); |
| 913 | |
| 914 | /* First decode all the insns in the CIE. */ |
| 915 | execute_cfa_program (fde, fde->cie->initial_instructions, |
| 916 | fde->cie->end, gdbarch, pc, &fs); |
| 917 | |
| 918 | /* Save the initialized register set. */ |
| 919 | fs.initial = fs.regs; |
| 920 | fs.initial.reg = dwarf2_frame_state_copy_regs (&fs.regs); |
| 921 | |
| 922 | /* Then decode the insns in the FDE up to our target PC. */ |
| 923 | execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs); |
| 924 | |
| 925 | /* Calculate the CFA. */ |
| 926 | switch (fs.regs.cfa_how) |
| 927 | { |
| 928 | case CFA_REG_OFFSET: |
| 929 | { |
| 930 | int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, fs.regs.cfa_reg); |
| 931 | |
| 932 | if (regnum == -1) |
| 933 | error (_("Unable to access DWARF register number %d"), |
| 934 | (int) fs.regs.cfa_reg); /* FIXME */ |
| 935 | ax_reg (expr, regnum); |
| 936 | |
| 937 | if (fs.regs.cfa_offset != 0) |
| 938 | { |
| 939 | if (fs.armcc_cfa_offsets_reversed) |
| 940 | ax_const_l (expr, -fs.regs.cfa_offset); |
| 941 | else |
| 942 | ax_const_l (expr, fs.regs.cfa_offset); |
| 943 | ax_simple (expr, aop_add); |
| 944 | } |
| 945 | } |
| 946 | break; |
| 947 | |
| 948 | case CFA_EXP: |
| 949 | ax_const_l (expr, text_offset); |
| 950 | dwarf2_compile_expr_to_ax (expr, loc, gdbarch, addr_size, |
| 951 | fs.regs.cfa_exp, |
| 952 | fs.regs.cfa_exp + fs.regs.cfa_exp_len, |
| 953 | data); |
| 954 | break; |
| 955 | |
| 956 | default: |
| 957 | internal_error (__FILE__, __LINE__, _("Unknown CFA rule.")); |
| 958 | } |
| 959 | } |
| 960 | |
| 961 | \f |
| 962 | struct dwarf2_frame_cache |
| 963 | { |
| 964 | /* DWARF Call Frame Address. */ |
| 965 | CORE_ADDR cfa; |
| 966 | |
| 967 | /* Set if the return address column was marked as unavailable |
| 968 | (required non-collected memory or registers to compute). */ |
| 969 | int unavailable_retaddr; |
| 970 | |
| 971 | /* Set if the return address column was marked as undefined. */ |
| 972 | int undefined_retaddr; |
| 973 | |
| 974 | /* Saved registers, indexed by GDB register number, not by DWARF |
| 975 | register number. */ |
| 976 | struct dwarf2_frame_state_reg *reg; |
| 977 | |
| 978 | /* Return address register. */ |
| 979 | struct dwarf2_frame_state_reg retaddr_reg; |
| 980 | |
| 981 | /* Target address size in bytes. */ |
| 982 | int addr_size; |
| 983 | |
| 984 | /* The .text offset. */ |
| 985 | CORE_ADDR text_offset; |
| 986 | |
| 987 | /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME |
| 988 | sequence. If NULL then it is a normal case with no TAILCALL_FRAME |
| 989 | involved. Non-bottom frames of a virtual tail call frames chain use |
| 990 | dwarf2_tailcall_frame_unwind unwinder so this field does not apply for |
| 991 | them. */ |
| 992 | void *tailcall_cache; |
| 993 | }; |
| 994 | |
| 995 | /* A cleanup that sets a pointer to NULL. */ |
| 996 | |
| 997 | static void |
| 998 | clear_pointer_cleanup (void *arg) |
| 999 | { |
| 1000 | void **ptr = arg; |
| 1001 | |
| 1002 | *ptr = NULL; |
| 1003 | } |
| 1004 | |
| 1005 | static struct dwarf2_frame_cache * |
| 1006 | dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache) |
| 1007 | { |
| 1008 | struct cleanup *reset_cache_cleanup, *old_chain; |
| 1009 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 1010 | const int num_regs = gdbarch_num_regs (gdbarch) |
| 1011 | + gdbarch_num_pseudo_regs (gdbarch); |
| 1012 | struct dwarf2_frame_cache *cache; |
| 1013 | struct dwarf2_frame_state *fs; |
| 1014 | struct dwarf2_fde *fde; |
| 1015 | volatile struct gdb_exception ex; |
| 1016 | CORE_ADDR entry_pc; |
| 1017 | LONGEST entry_cfa_sp_offset; |
| 1018 | int entry_cfa_sp_offset_p = 0; |
| 1019 | const gdb_byte *instr; |
| 1020 | |
| 1021 | if (*this_cache) |
| 1022 | return *this_cache; |
| 1023 | |
| 1024 | /* Allocate a new cache. */ |
| 1025 | cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache); |
| 1026 | cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg); |
| 1027 | *this_cache = cache; |
| 1028 | reset_cache_cleanup = make_cleanup (clear_pointer_cleanup, this_cache); |
| 1029 | |
| 1030 | /* Allocate and initialize the frame state. */ |
| 1031 | fs = XZALLOC (struct dwarf2_frame_state); |
| 1032 | old_chain = make_cleanup (dwarf2_frame_state_free, fs); |
| 1033 | |
| 1034 | /* Unwind the PC. |
| 1035 | |
| 1036 | Note that if the next frame is never supposed to return (i.e. a call |
| 1037 | to abort), the compiler might optimize away the instruction at |
| 1038 | its return address. As a result the return address will |
| 1039 | point at some random instruction, and the CFI for that |
| 1040 | instruction is probably worthless to us. GCC's unwinder solves |
| 1041 | this problem by substracting 1 from the return address to get an |
| 1042 | address in the middle of a presumed call instruction (or the |
| 1043 | instruction in the associated delay slot). This should only be |
| 1044 | done for "normal" frames and not for resume-type frames (signal |
| 1045 | handlers, sentinel frames, dummy frames). The function |
| 1046 | get_frame_address_in_block does just this. It's not clear how |
| 1047 | reliable the method is though; there is the potential for the |
| 1048 | register state pre-call being different to that on return. */ |
| 1049 | fs->pc = get_frame_address_in_block (this_frame); |
| 1050 | |
| 1051 | /* Find the correct FDE. */ |
| 1052 | fde = dwarf2_frame_find_fde (&fs->pc, &cache->text_offset); |
| 1053 | gdb_assert (fde != NULL); |
| 1054 | |
| 1055 | /* Extract any interesting information from the CIE. */ |
| 1056 | fs->data_align = fde->cie->data_alignment_factor; |
| 1057 | fs->code_align = fde->cie->code_alignment_factor; |
| 1058 | fs->retaddr_column = fde->cie->return_address_register; |
| 1059 | cache->addr_size = fde->cie->addr_size; |
| 1060 | |
| 1061 | /* Check for "quirks" - known bugs in producers. */ |
| 1062 | dwarf2_frame_find_quirks (fs, fde); |
| 1063 | |
| 1064 | /* First decode all the insns in the CIE. */ |
| 1065 | execute_cfa_program (fde, fde->cie->initial_instructions, |
| 1066 | fde->cie->end, gdbarch, |
| 1067 | get_frame_address_in_block (this_frame), fs); |
| 1068 | |
| 1069 | /* Save the initialized register set. */ |
| 1070 | fs->initial = fs->regs; |
| 1071 | fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs); |
| 1072 | |
| 1073 | if (get_frame_func_if_available (this_frame, &entry_pc)) |
| 1074 | { |
| 1075 | /* Decode the insns in the FDE up to the entry PC. */ |
| 1076 | instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, |
| 1077 | entry_pc, fs); |
| 1078 | |
| 1079 | if (fs->regs.cfa_how == CFA_REG_OFFSET |
| 1080 | && (gdbarch_dwarf2_reg_to_regnum (gdbarch, fs->regs.cfa_reg) |
| 1081 | == gdbarch_sp_regnum (gdbarch))) |
| 1082 | { |
| 1083 | entry_cfa_sp_offset = fs->regs.cfa_offset; |
| 1084 | entry_cfa_sp_offset_p = 1; |
| 1085 | } |
| 1086 | } |
| 1087 | else |
| 1088 | instr = fde->instructions; |
| 1089 | |
| 1090 | /* Then decode the insns in the FDE up to our target PC. */ |
| 1091 | execute_cfa_program (fde, instr, fde->end, gdbarch, |
| 1092 | get_frame_address_in_block (this_frame), fs); |
| 1093 | |
| 1094 | TRY_CATCH (ex, RETURN_MASK_ERROR) |
| 1095 | { |
| 1096 | /* Calculate the CFA. */ |
| 1097 | switch (fs->regs.cfa_how) |
| 1098 | { |
| 1099 | case CFA_REG_OFFSET: |
| 1100 | cache->cfa = read_reg (this_frame, fs->regs.cfa_reg); |
| 1101 | if (fs->armcc_cfa_offsets_reversed) |
| 1102 | cache->cfa -= fs->regs.cfa_offset; |
| 1103 | else |
| 1104 | cache->cfa += fs->regs.cfa_offset; |
| 1105 | break; |
| 1106 | |
| 1107 | case CFA_EXP: |
| 1108 | cache->cfa = |
| 1109 | execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len, |
| 1110 | cache->addr_size, cache->text_offset, |
| 1111 | this_frame, 0, 0); |
| 1112 | break; |
| 1113 | |
| 1114 | default: |
| 1115 | internal_error (__FILE__, __LINE__, _("Unknown CFA rule.")); |
| 1116 | } |
| 1117 | } |
| 1118 | if (ex.reason < 0) |
| 1119 | { |
| 1120 | if (ex.error == NOT_AVAILABLE_ERROR) |
| 1121 | { |
| 1122 | cache->unavailable_retaddr = 1; |
| 1123 | do_cleanups (old_chain); |
| 1124 | discard_cleanups (reset_cache_cleanup); |
| 1125 | return cache; |
| 1126 | } |
| 1127 | |
| 1128 | throw_exception (ex); |
| 1129 | } |
| 1130 | |
| 1131 | /* Initialize the register state. */ |
| 1132 | { |
| 1133 | int regnum; |
| 1134 | |
| 1135 | for (regnum = 0; regnum < num_regs; regnum++) |
| 1136 | dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame); |
| 1137 | } |
| 1138 | |
| 1139 | /* Go through the DWARF2 CFI generated table and save its register |
| 1140 | location information in the cache. Note that we don't skip the |
| 1141 | return address column; it's perfectly all right for it to |
| 1142 | correspond to a real register. If it doesn't correspond to a |
| 1143 | real register, or if we shouldn't treat it as such, |
| 1144 | gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside |
| 1145 | the range [0, gdbarch_num_regs). */ |
| 1146 | { |
| 1147 | int column; /* CFI speak for "register number". */ |
| 1148 | |
| 1149 | for (column = 0; column < fs->regs.num_regs; column++) |
| 1150 | { |
| 1151 | /* Use the GDB register number as the destination index. */ |
| 1152 | int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column); |
| 1153 | |
| 1154 | /* If there's no corresponding GDB register, ignore it. */ |
| 1155 | if (regnum < 0 || regnum >= num_regs) |
| 1156 | continue; |
| 1157 | |
| 1158 | /* NOTE: cagney/2003-09-05: CFI should specify the disposition |
| 1159 | of all debug info registers. If it doesn't, complain (but |
| 1160 | not too loudly). It turns out that GCC assumes that an |
| 1161 | unspecified register implies "same value" when CFI (draft |
| 1162 | 7) specifies nothing at all. Such a register could equally |
| 1163 | be interpreted as "undefined". Also note that this check |
| 1164 | isn't sufficient; it only checks that all registers in the |
| 1165 | range [0 .. max column] are specified, and won't detect |
| 1166 | problems when a debug info register falls outside of the |
| 1167 | table. We need a way of iterating through all the valid |
| 1168 | DWARF2 register numbers. */ |
| 1169 | if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 1170 | { |
| 1171 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 1172 | complaint (&symfile_complaints, _("\ |
| 1173 | incomplete CFI data; unspecified registers (e.g., %s) at %s"), |
| 1174 | gdbarch_register_name (gdbarch, regnum), |
| 1175 | paddress (gdbarch, fs->pc)); |
| 1176 | } |
| 1177 | else |
| 1178 | cache->reg[regnum] = fs->regs.reg[column]; |
| 1179 | } |
| 1180 | } |
| 1181 | |
| 1182 | /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information |
| 1183 | we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */ |
| 1184 | { |
| 1185 | int regnum; |
| 1186 | |
| 1187 | for (regnum = 0; regnum < num_regs; regnum++) |
| 1188 | { |
| 1189 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA |
| 1190 | || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET) |
| 1191 | { |
| 1192 | struct dwarf2_frame_state_reg *retaddr_reg = |
| 1193 | &fs->regs.reg[fs->retaddr_column]; |
| 1194 | |
| 1195 | /* It seems rather bizarre to specify an "empty" column as |
| 1196 | the return adress column. However, this is exactly |
| 1197 | what GCC does on some targets. It turns out that GCC |
| 1198 | assumes that the return address can be found in the |
| 1199 | register corresponding to the return address column. |
| 1200 | Incidentally, that's how we should treat a return |
| 1201 | address column specifying "same value" too. */ |
| 1202 | if (fs->retaddr_column < fs->regs.num_regs |
| 1203 | && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED |
| 1204 | && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE) |
| 1205 | { |
| 1206 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) |
| 1207 | cache->reg[regnum] = *retaddr_reg; |
| 1208 | else |
| 1209 | cache->retaddr_reg = *retaddr_reg; |
| 1210 | } |
| 1211 | else |
| 1212 | { |
| 1213 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) |
| 1214 | { |
| 1215 | cache->reg[regnum].loc.reg = fs->retaddr_column; |
| 1216 | cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG; |
| 1217 | } |
| 1218 | else |
| 1219 | { |
| 1220 | cache->retaddr_reg.loc.reg = fs->retaddr_column; |
| 1221 | cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG; |
| 1222 | } |
| 1223 | } |
| 1224 | } |
| 1225 | } |
| 1226 | } |
| 1227 | |
| 1228 | if (fs->retaddr_column < fs->regs.num_regs |
| 1229 | && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED) |
| 1230 | cache->undefined_retaddr = 1; |
| 1231 | |
| 1232 | do_cleanups (old_chain); |
| 1233 | |
| 1234 | /* Try to find a virtual tail call frames chain with bottom (callee) frame |
| 1235 | starting at THIS_FRAME. */ |
| 1236 | dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache, |
| 1237 | (entry_cfa_sp_offset_p |
| 1238 | ? &entry_cfa_sp_offset : NULL)); |
| 1239 | |
| 1240 | discard_cleanups (reset_cache_cleanup); |
| 1241 | return cache; |
| 1242 | } |
| 1243 | |
| 1244 | static enum unwind_stop_reason |
| 1245 | dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame, |
| 1246 | void **this_cache) |
| 1247 | { |
| 1248 | struct dwarf2_frame_cache *cache |
| 1249 | = dwarf2_frame_cache (this_frame, this_cache); |
| 1250 | |
| 1251 | if (cache->unavailable_retaddr) |
| 1252 | return UNWIND_UNAVAILABLE; |
| 1253 | |
| 1254 | if (cache->undefined_retaddr) |
| 1255 | return UNWIND_OUTERMOST; |
| 1256 | |
| 1257 | return UNWIND_NO_REASON; |
| 1258 | } |
| 1259 | |
| 1260 | static void |
| 1261 | dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache, |
| 1262 | struct frame_id *this_id) |
| 1263 | { |
| 1264 | struct dwarf2_frame_cache *cache = |
| 1265 | dwarf2_frame_cache (this_frame, this_cache); |
| 1266 | |
| 1267 | if (cache->unavailable_retaddr) |
| 1268 | return; |
| 1269 | |
| 1270 | if (cache->undefined_retaddr) |
| 1271 | return; |
| 1272 | |
| 1273 | (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame)); |
| 1274 | } |
| 1275 | |
| 1276 | static struct value * |
| 1277 | dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache, |
| 1278 | int regnum) |
| 1279 | { |
| 1280 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 1281 | struct dwarf2_frame_cache *cache = |
| 1282 | dwarf2_frame_cache (this_frame, this_cache); |
| 1283 | CORE_ADDR addr; |
| 1284 | int realnum; |
| 1285 | |
| 1286 | /* Non-bottom frames of a virtual tail call frames chain use |
| 1287 | dwarf2_tailcall_frame_unwind unwinder so this code does not apply for |
| 1288 | them. If dwarf2_tailcall_prev_register_first does not have specific value |
| 1289 | unwind the register, tail call frames are assumed to have the register set |
| 1290 | of the top caller. */ |
| 1291 | if (cache->tailcall_cache) |
| 1292 | { |
| 1293 | struct value *val; |
| 1294 | |
| 1295 | val = dwarf2_tailcall_prev_register_first (this_frame, |
| 1296 | &cache->tailcall_cache, |
| 1297 | regnum); |
| 1298 | if (val) |
| 1299 | return val; |
| 1300 | } |
| 1301 | |
| 1302 | switch (cache->reg[regnum].how) |
| 1303 | { |
| 1304 | case DWARF2_FRAME_REG_UNDEFINED: |
| 1305 | /* If CFI explicitly specified that the value isn't defined, |
| 1306 | mark it as optimized away; the value isn't available. */ |
| 1307 | return frame_unwind_got_optimized (this_frame, regnum); |
| 1308 | |
| 1309 | case DWARF2_FRAME_REG_SAVED_OFFSET: |
| 1310 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1311 | return frame_unwind_got_memory (this_frame, regnum, addr); |
| 1312 | |
| 1313 | case DWARF2_FRAME_REG_SAVED_REG: |
| 1314 | realnum |
| 1315 | = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg); |
| 1316 | return frame_unwind_got_register (this_frame, regnum, realnum); |
| 1317 | |
| 1318 | case DWARF2_FRAME_REG_SAVED_EXP: |
| 1319 | addr = execute_stack_op (cache->reg[regnum].loc.exp, |
| 1320 | cache->reg[regnum].exp_len, |
| 1321 | cache->addr_size, cache->text_offset, |
| 1322 | this_frame, cache->cfa, 1); |
| 1323 | return frame_unwind_got_memory (this_frame, regnum, addr); |
| 1324 | |
| 1325 | case DWARF2_FRAME_REG_SAVED_VAL_OFFSET: |
| 1326 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1327 | return frame_unwind_got_constant (this_frame, regnum, addr); |
| 1328 | |
| 1329 | case DWARF2_FRAME_REG_SAVED_VAL_EXP: |
| 1330 | addr = execute_stack_op (cache->reg[regnum].loc.exp, |
| 1331 | cache->reg[regnum].exp_len, |
| 1332 | cache->addr_size, cache->text_offset, |
| 1333 | this_frame, cache->cfa, 1); |
| 1334 | return frame_unwind_got_constant (this_frame, regnum, addr); |
| 1335 | |
| 1336 | case DWARF2_FRAME_REG_UNSPECIFIED: |
| 1337 | /* GCC, in its infinite wisdom decided to not provide unwind |
| 1338 | information for registers that are "same value". Since |
| 1339 | DWARF2 (3 draft 7) doesn't define such behavior, said |
| 1340 | registers are actually undefined (which is different to CFI |
| 1341 | "undefined"). Code above issues a complaint about this. |
| 1342 | Here just fudge the books, assume GCC, and that the value is |
| 1343 | more inner on the stack. */ |
| 1344 | return frame_unwind_got_register (this_frame, regnum, regnum); |
| 1345 | |
| 1346 | case DWARF2_FRAME_REG_SAME_VALUE: |
| 1347 | return frame_unwind_got_register (this_frame, regnum, regnum); |
| 1348 | |
| 1349 | case DWARF2_FRAME_REG_CFA: |
| 1350 | return frame_unwind_got_address (this_frame, regnum, cache->cfa); |
| 1351 | |
| 1352 | case DWARF2_FRAME_REG_CFA_OFFSET: |
| 1353 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1354 | return frame_unwind_got_address (this_frame, regnum, addr); |
| 1355 | |
| 1356 | case DWARF2_FRAME_REG_RA_OFFSET: |
| 1357 | addr = cache->reg[regnum].loc.offset; |
| 1358 | regnum = gdbarch_dwarf2_reg_to_regnum |
| 1359 | (gdbarch, cache->retaddr_reg.loc.reg); |
| 1360 | addr += get_frame_register_unsigned (this_frame, regnum); |
| 1361 | return frame_unwind_got_address (this_frame, regnum, addr); |
| 1362 | |
| 1363 | case DWARF2_FRAME_REG_FN: |
| 1364 | return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum); |
| 1365 | |
| 1366 | default: |
| 1367 | internal_error (__FILE__, __LINE__, _("Unknown register rule.")); |
| 1368 | } |
| 1369 | } |
| 1370 | |
| 1371 | /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail |
| 1372 | call frames chain. */ |
| 1373 | |
| 1374 | static void |
| 1375 | dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache) |
| 1376 | { |
| 1377 | struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache); |
| 1378 | |
| 1379 | if (cache->tailcall_cache) |
| 1380 | dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache); |
| 1381 | } |
| 1382 | |
| 1383 | static int |
| 1384 | dwarf2_frame_sniffer (const struct frame_unwind *self, |
| 1385 | struct frame_info *this_frame, void **this_cache) |
| 1386 | { |
| 1387 | /* Grab an address that is guarenteed to reside somewhere within the |
| 1388 | function. get_frame_pc(), with a no-return next function, can |
| 1389 | end up returning something past the end of this function's body. |
| 1390 | If the frame we're sniffing for is a signal frame whose start |
| 1391 | address is placed on the stack by the OS, its FDE must |
| 1392 | extend one byte before its start address or we could potentially |
| 1393 | select the FDE of the previous function. */ |
| 1394 | CORE_ADDR block_addr = get_frame_address_in_block (this_frame); |
| 1395 | struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL); |
| 1396 | |
| 1397 | if (!fde) |
| 1398 | return 0; |
| 1399 | |
| 1400 | /* On some targets, signal trampolines may have unwind information. |
| 1401 | We need to recognize them so that we set the frame type |
| 1402 | correctly. */ |
| 1403 | |
| 1404 | if (fde->cie->signal_frame |
| 1405 | || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame), |
| 1406 | this_frame)) |
| 1407 | return self->type == SIGTRAMP_FRAME; |
| 1408 | |
| 1409 | if (self->type != NORMAL_FRAME) |
| 1410 | return 0; |
| 1411 | |
| 1412 | /* Preinitializa the cache so that TAILCALL_FRAME can find the record by |
| 1413 | dwarf2_tailcall_sniffer_first. */ |
| 1414 | dwarf2_frame_cache (this_frame, this_cache); |
| 1415 | |
| 1416 | return 1; |
| 1417 | } |
| 1418 | |
| 1419 | static const struct frame_unwind dwarf2_frame_unwind = |
| 1420 | { |
| 1421 | NORMAL_FRAME, |
| 1422 | dwarf2_frame_unwind_stop_reason, |
| 1423 | dwarf2_frame_this_id, |
| 1424 | dwarf2_frame_prev_register, |
| 1425 | NULL, |
| 1426 | dwarf2_frame_sniffer, |
| 1427 | dwarf2_frame_dealloc_cache |
| 1428 | }; |
| 1429 | |
| 1430 | static const struct frame_unwind dwarf2_signal_frame_unwind = |
| 1431 | { |
| 1432 | SIGTRAMP_FRAME, |
| 1433 | dwarf2_frame_unwind_stop_reason, |
| 1434 | dwarf2_frame_this_id, |
| 1435 | dwarf2_frame_prev_register, |
| 1436 | NULL, |
| 1437 | dwarf2_frame_sniffer, |
| 1438 | |
| 1439 | /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */ |
| 1440 | NULL |
| 1441 | }; |
| 1442 | |
| 1443 | /* Append the DWARF-2 frame unwinders to GDBARCH's list. */ |
| 1444 | |
| 1445 | void |
| 1446 | dwarf2_append_unwinders (struct gdbarch *gdbarch) |
| 1447 | { |
| 1448 | /* TAILCALL_FRAME must be first to find the record by |
| 1449 | dwarf2_tailcall_sniffer_first. */ |
| 1450 | frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind); |
| 1451 | |
| 1452 | frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind); |
| 1453 | frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind); |
| 1454 | } |
| 1455 | \f |
| 1456 | |
| 1457 | /* There is no explicitly defined relationship between the CFA and the |
| 1458 | location of frame's local variables and arguments/parameters. |
| 1459 | Therefore, frame base methods on this page should probably only be |
| 1460 | used as a last resort, just to avoid printing total garbage as a |
| 1461 | response to the "info frame" command. */ |
| 1462 | |
| 1463 | static CORE_ADDR |
| 1464 | dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache) |
| 1465 | { |
| 1466 | struct dwarf2_frame_cache *cache = |
| 1467 | dwarf2_frame_cache (this_frame, this_cache); |
| 1468 | |
| 1469 | return cache->cfa; |
| 1470 | } |
| 1471 | |
| 1472 | static const struct frame_base dwarf2_frame_base = |
| 1473 | { |
| 1474 | &dwarf2_frame_unwind, |
| 1475 | dwarf2_frame_base_address, |
| 1476 | dwarf2_frame_base_address, |
| 1477 | dwarf2_frame_base_address |
| 1478 | }; |
| 1479 | |
| 1480 | const struct frame_base * |
| 1481 | dwarf2_frame_base_sniffer (struct frame_info *this_frame) |
| 1482 | { |
| 1483 | CORE_ADDR block_addr = get_frame_address_in_block (this_frame); |
| 1484 | |
| 1485 | if (dwarf2_frame_find_fde (&block_addr, NULL)) |
| 1486 | return &dwarf2_frame_base; |
| 1487 | |
| 1488 | return NULL; |
| 1489 | } |
| 1490 | |
| 1491 | /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from |
| 1492 | the DWARF unwinder. This is used to implement |
| 1493 | DW_OP_call_frame_cfa. */ |
| 1494 | |
| 1495 | CORE_ADDR |
| 1496 | dwarf2_frame_cfa (struct frame_info *this_frame) |
| 1497 | { |
| 1498 | while (get_frame_type (this_frame) == INLINE_FRAME) |
| 1499 | this_frame = get_prev_frame (this_frame); |
| 1500 | /* This restriction could be lifted if other unwinders are known to |
| 1501 | compute the frame base in a way compatible with the DWARF |
| 1502 | unwinder. */ |
| 1503 | if (!frame_unwinder_is (this_frame, &dwarf2_frame_unwind) |
| 1504 | && !frame_unwinder_is (this_frame, &dwarf2_tailcall_frame_unwind)) |
| 1505 | error (_("can't compute CFA for this frame")); |
| 1506 | if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE) |
| 1507 | throw_error (NOT_AVAILABLE_ERROR, |
| 1508 | _("can't compute CFA for this frame: " |
| 1509 | "required registers or memory are unavailable")); |
| 1510 | return get_frame_base (this_frame); |
| 1511 | } |
| 1512 | \f |
| 1513 | const struct objfile_data *dwarf2_frame_objfile_data; |
| 1514 | |
| 1515 | static unsigned int |
| 1516 | read_1_byte (bfd *abfd, const gdb_byte *buf) |
| 1517 | { |
| 1518 | return bfd_get_8 (abfd, buf); |
| 1519 | } |
| 1520 | |
| 1521 | static unsigned int |
| 1522 | read_4_bytes (bfd *abfd, const gdb_byte *buf) |
| 1523 | { |
| 1524 | return bfd_get_32 (abfd, buf); |
| 1525 | } |
| 1526 | |
| 1527 | static ULONGEST |
| 1528 | read_8_bytes (bfd *abfd, const gdb_byte *buf) |
| 1529 | { |
| 1530 | return bfd_get_64 (abfd, buf); |
| 1531 | } |
| 1532 | |
| 1533 | static ULONGEST |
| 1534 | read_initial_length (bfd *abfd, const gdb_byte *buf, |
| 1535 | unsigned int *bytes_read_ptr) |
| 1536 | { |
| 1537 | LONGEST result; |
| 1538 | |
| 1539 | result = bfd_get_32 (abfd, buf); |
| 1540 | if (result == 0xffffffff) |
| 1541 | { |
| 1542 | result = bfd_get_64 (abfd, buf + 4); |
| 1543 | *bytes_read_ptr = 12; |
| 1544 | } |
| 1545 | else |
| 1546 | *bytes_read_ptr = 4; |
| 1547 | |
| 1548 | return result; |
| 1549 | } |
| 1550 | \f |
| 1551 | |
| 1552 | /* Pointer encoding helper functions. */ |
| 1553 | |
| 1554 | /* GCC supports exception handling based on DWARF2 CFI. However, for |
| 1555 | technical reasons, it encodes addresses in its FDE's in a different |
| 1556 | way. Several "pointer encodings" are supported. The encoding |
| 1557 | that's used for a particular FDE is determined by the 'R' |
| 1558 | augmentation in the associated CIE. The argument of this |
| 1559 | augmentation is a single byte. |
| 1560 | |
| 1561 | The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a |
| 1562 | LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether |
| 1563 | the address is signed or unsigned. Bits 4, 5 and 6 encode how the |
| 1564 | address should be interpreted (absolute, relative to the current |
| 1565 | position in the FDE, ...). Bit 7, indicates that the address |
| 1566 | should be dereferenced. */ |
| 1567 | |
| 1568 | static gdb_byte |
| 1569 | encoding_for_size (unsigned int size) |
| 1570 | { |
| 1571 | switch (size) |
| 1572 | { |
| 1573 | case 2: |
| 1574 | return DW_EH_PE_udata2; |
| 1575 | case 4: |
| 1576 | return DW_EH_PE_udata4; |
| 1577 | case 8: |
| 1578 | return DW_EH_PE_udata8; |
| 1579 | default: |
| 1580 | internal_error (__FILE__, __LINE__, _("Unsupported address size")); |
| 1581 | } |
| 1582 | } |
| 1583 | |
| 1584 | static CORE_ADDR |
| 1585 | read_encoded_value (struct comp_unit *unit, gdb_byte encoding, |
| 1586 | int ptr_len, const gdb_byte *buf, |
| 1587 | unsigned int *bytes_read_ptr, |
| 1588 | CORE_ADDR func_base) |
| 1589 | { |
| 1590 | ptrdiff_t offset; |
| 1591 | CORE_ADDR base; |
| 1592 | |
| 1593 | /* GCC currently doesn't generate DW_EH_PE_indirect encodings for |
| 1594 | FDE's. */ |
| 1595 | if (encoding & DW_EH_PE_indirect) |
| 1596 | internal_error (__FILE__, __LINE__, |
| 1597 | _("Unsupported encoding: DW_EH_PE_indirect")); |
| 1598 | |
| 1599 | *bytes_read_ptr = 0; |
| 1600 | |
| 1601 | switch (encoding & 0x70) |
| 1602 | { |
| 1603 | case DW_EH_PE_absptr: |
| 1604 | base = 0; |
| 1605 | break; |
| 1606 | case DW_EH_PE_pcrel: |
| 1607 | base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section); |
| 1608 | base += (buf - unit->dwarf_frame_buffer); |
| 1609 | break; |
| 1610 | case DW_EH_PE_datarel: |
| 1611 | base = unit->dbase; |
| 1612 | break; |
| 1613 | case DW_EH_PE_textrel: |
| 1614 | base = unit->tbase; |
| 1615 | break; |
| 1616 | case DW_EH_PE_funcrel: |
| 1617 | base = func_base; |
| 1618 | break; |
| 1619 | case DW_EH_PE_aligned: |
| 1620 | base = 0; |
| 1621 | offset = buf - unit->dwarf_frame_buffer; |
| 1622 | if ((offset % ptr_len) != 0) |
| 1623 | { |
| 1624 | *bytes_read_ptr = ptr_len - (offset % ptr_len); |
| 1625 | buf += *bytes_read_ptr; |
| 1626 | } |
| 1627 | break; |
| 1628 | default: |
| 1629 | internal_error (__FILE__, __LINE__, |
| 1630 | _("Invalid or unsupported encoding")); |
| 1631 | } |
| 1632 | |
| 1633 | if ((encoding & 0x07) == 0x00) |
| 1634 | { |
| 1635 | encoding |= encoding_for_size (ptr_len); |
| 1636 | if (bfd_get_sign_extend_vma (unit->abfd)) |
| 1637 | encoding |= DW_EH_PE_signed; |
| 1638 | } |
| 1639 | |
| 1640 | switch (encoding & 0x0f) |
| 1641 | { |
| 1642 | case DW_EH_PE_uleb128: |
| 1643 | { |
| 1644 | uint64_t value; |
| 1645 | const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
| 1646 | |
| 1647 | *bytes_read_ptr += safe_read_uleb128 (buf, end_buf, &value) - buf; |
| 1648 | return base + value; |
| 1649 | } |
| 1650 | case DW_EH_PE_udata2: |
| 1651 | *bytes_read_ptr += 2; |
| 1652 | return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf)); |
| 1653 | case DW_EH_PE_udata4: |
| 1654 | *bytes_read_ptr += 4; |
| 1655 | return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf)); |
| 1656 | case DW_EH_PE_udata8: |
| 1657 | *bytes_read_ptr += 8; |
| 1658 | return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf)); |
| 1659 | case DW_EH_PE_sleb128: |
| 1660 | { |
| 1661 | int64_t value; |
| 1662 | const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
| 1663 | |
| 1664 | *bytes_read_ptr += safe_read_sleb128 (buf, end_buf, &value) - buf; |
| 1665 | return base + value; |
| 1666 | } |
| 1667 | case DW_EH_PE_sdata2: |
| 1668 | *bytes_read_ptr += 2; |
| 1669 | return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf)); |
| 1670 | case DW_EH_PE_sdata4: |
| 1671 | *bytes_read_ptr += 4; |
| 1672 | return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf)); |
| 1673 | case DW_EH_PE_sdata8: |
| 1674 | *bytes_read_ptr += 8; |
| 1675 | return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf)); |
| 1676 | default: |
| 1677 | internal_error (__FILE__, __LINE__, |
| 1678 | _("Invalid or unsupported encoding")); |
| 1679 | } |
| 1680 | } |
| 1681 | \f |
| 1682 | |
| 1683 | static int |
| 1684 | bsearch_cie_cmp (const void *key, const void *element) |
| 1685 | { |
| 1686 | ULONGEST cie_pointer = *(ULONGEST *) key; |
| 1687 | struct dwarf2_cie *cie = *(struct dwarf2_cie **) element; |
| 1688 | |
| 1689 | if (cie_pointer == cie->cie_pointer) |
| 1690 | return 0; |
| 1691 | |
| 1692 | return (cie_pointer < cie->cie_pointer) ? -1 : 1; |
| 1693 | } |
| 1694 | |
| 1695 | /* Find CIE with the given CIE_POINTER in CIE_TABLE. */ |
| 1696 | static struct dwarf2_cie * |
| 1697 | find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer) |
| 1698 | { |
| 1699 | struct dwarf2_cie **p_cie; |
| 1700 | |
| 1701 | /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to |
| 1702 | bsearch be non-NULL. */ |
| 1703 | if (cie_table->entries == NULL) |
| 1704 | { |
| 1705 | gdb_assert (cie_table->num_entries == 0); |
| 1706 | return NULL; |
| 1707 | } |
| 1708 | |
| 1709 | p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries, |
| 1710 | sizeof (cie_table->entries[0]), bsearch_cie_cmp); |
| 1711 | if (p_cie != NULL) |
| 1712 | return *p_cie; |
| 1713 | return NULL; |
| 1714 | } |
| 1715 | |
| 1716 | /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */ |
| 1717 | static void |
| 1718 | add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie) |
| 1719 | { |
| 1720 | const int n = cie_table->num_entries; |
| 1721 | |
| 1722 | gdb_assert (n < 1 |
| 1723 | || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer); |
| 1724 | |
| 1725 | cie_table->entries = |
| 1726 | xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0])); |
| 1727 | cie_table->entries[n] = cie; |
| 1728 | cie_table->num_entries = n + 1; |
| 1729 | } |
| 1730 | |
| 1731 | static int |
| 1732 | bsearch_fde_cmp (const void *key, const void *element) |
| 1733 | { |
| 1734 | CORE_ADDR seek_pc = *(CORE_ADDR *) key; |
| 1735 | struct dwarf2_fde *fde = *(struct dwarf2_fde **) element; |
| 1736 | |
| 1737 | if (seek_pc < fde->initial_location) |
| 1738 | return -1; |
| 1739 | if (seek_pc < fde->initial_location + fde->address_range) |
| 1740 | return 0; |
| 1741 | return 1; |
| 1742 | } |
| 1743 | |
| 1744 | /* Find the FDE for *PC. Return a pointer to the FDE, and store the |
| 1745 | inital location associated with it into *PC. */ |
| 1746 | |
| 1747 | static struct dwarf2_fde * |
| 1748 | dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset) |
| 1749 | { |
| 1750 | struct objfile *objfile; |
| 1751 | |
| 1752 | ALL_OBJFILES (objfile) |
| 1753 | { |
| 1754 | struct dwarf2_fde_table *fde_table; |
| 1755 | struct dwarf2_fde **p_fde; |
| 1756 | CORE_ADDR offset; |
| 1757 | CORE_ADDR seek_pc; |
| 1758 | |
| 1759 | fde_table = objfile_data (objfile, dwarf2_frame_objfile_data); |
| 1760 | if (fde_table == NULL) |
| 1761 | { |
| 1762 | dwarf2_build_frame_info (objfile); |
| 1763 | fde_table = objfile_data (objfile, dwarf2_frame_objfile_data); |
| 1764 | } |
| 1765 | gdb_assert (fde_table != NULL); |
| 1766 | |
| 1767 | if (fde_table->num_entries == 0) |
| 1768 | continue; |
| 1769 | |
| 1770 | gdb_assert (objfile->section_offsets); |
| 1771 | offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); |
| 1772 | |
| 1773 | gdb_assert (fde_table->num_entries > 0); |
| 1774 | if (*pc < offset + fde_table->entries[0]->initial_location) |
| 1775 | continue; |
| 1776 | |
| 1777 | seek_pc = *pc - offset; |
| 1778 | p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries, |
| 1779 | sizeof (fde_table->entries[0]), bsearch_fde_cmp); |
| 1780 | if (p_fde != NULL) |
| 1781 | { |
| 1782 | *pc = (*p_fde)->initial_location + offset; |
| 1783 | if (out_offset) |
| 1784 | *out_offset = offset; |
| 1785 | return *p_fde; |
| 1786 | } |
| 1787 | } |
| 1788 | return NULL; |
| 1789 | } |
| 1790 | |
| 1791 | /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */ |
| 1792 | static void |
| 1793 | add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde) |
| 1794 | { |
| 1795 | if (fde->address_range == 0) |
| 1796 | /* Discard useless FDEs. */ |
| 1797 | return; |
| 1798 | |
| 1799 | fde_table->num_entries += 1; |
| 1800 | fde_table->entries = |
| 1801 | xrealloc (fde_table->entries, |
| 1802 | fde_table->num_entries * sizeof (fde_table->entries[0])); |
| 1803 | fde_table->entries[fde_table->num_entries - 1] = fde; |
| 1804 | } |
| 1805 | |
| 1806 | #define DW64_CIE_ID 0xffffffffffffffffULL |
| 1807 | |
| 1808 | /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE |
| 1809 | or any of them. */ |
| 1810 | |
| 1811 | enum eh_frame_type |
| 1812 | { |
| 1813 | EH_CIE_TYPE_ID = 1 << 0, |
| 1814 | EH_FDE_TYPE_ID = 1 << 1, |
| 1815 | EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID |
| 1816 | }; |
| 1817 | |
| 1818 | static const gdb_byte *decode_frame_entry (struct comp_unit *unit, |
| 1819 | const gdb_byte *start, |
| 1820 | int eh_frame_p, |
| 1821 | struct dwarf2_cie_table *cie_table, |
| 1822 | struct dwarf2_fde_table *fde_table, |
| 1823 | enum eh_frame_type entry_type); |
| 1824 | |
| 1825 | /* Decode the next CIE or FDE, entry_type specifies the expected type. |
| 1826 | Return NULL if invalid input, otherwise the next byte to be processed. */ |
| 1827 | |
| 1828 | static const gdb_byte * |
| 1829 | decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start, |
| 1830 | int eh_frame_p, |
| 1831 | struct dwarf2_cie_table *cie_table, |
| 1832 | struct dwarf2_fde_table *fde_table, |
| 1833 | enum eh_frame_type entry_type) |
| 1834 | { |
| 1835 | struct gdbarch *gdbarch = get_objfile_arch (unit->objfile); |
| 1836 | const gdb_byte *buf, *end; |
| 1837 | LONGEST length; |
| 1838 | unsigned int bytes_read; |
| 1839 | int dwarf64_p; |
| 1840 | ULONGEST cie_id; |
| 1841 | ULONGEST cie_pointer; |
| 1842 | int64_t sleb128; |
| 1843 | uint64_t uleb128; |
| 1844 | |
| 1845 | buf = start; |
| 1846 | length = read_initial_length (unit->abfd, buf, &bytes_read); |
| 1847 | buf += bytes_read; |
| 1848 | end = buf + length; |
| 1849 | |
| 1850 | /* Are we still within the section? */ |
| 1851 | if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 1852 | return NULL; |
| 1853 | |
| 1854 | if (length == 0) |
| 1855 | return end; |
| 1856 | |
| 1857 | /* Distinguish between 32 and 64-bit encoded frame info. */ |
| 1858 | dwarf64_p = (bytes_read == 12); |
| 1859 | |
| 1860 | /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */ |
| 1861 | if (eh_frame_p) |
| 1862 | cie_id = 0; |
| 1863 | else if (dwarf64_p) |
| 1864 | cie_id = DW64_CIE_ID; |
| 1865 | else |
| 1866 | cie_id = DW_CIE_ID; |
| 1867 | |
| 1868 | if (dwarf64_p) |
| 1869 | { |
| 1870 | cie_pointer = read_8_bytes (unit->abfd, buf); |
| 1871 | buf += 8; |
| 1872 | } |
| 1873 | else |
| 1874 | { |
| 1875 | cie_pointer = read_4_bytes (unit->abfd, buf); |
| 1876 | buf += 4; |
| 1877 | } |
| 1878 | |
| 1879 | if (cie_pointer == cie_id) |
| 1880 | { |
| 1881 | /* This is a CIE. */ |
| 1882 | struct dwarf2_cie *cie; |
| 1883 | char *augmentation; |
| 1884 | unsigned int cie_version; |
| 1885 | |
| 1886 | /* Check that a CIE was expected. */ |
| 1887 | if ((entry_type & EH_CIE_TYPE_ID) == 0) |
| 1888 | error (_("Found a CIE when not expecting it.")); |
| 1889 | |
| 1890 | /* Record the offset into the .debug_frame section of this CIE. */ |
| 1891 | cie_pointer = start - unit->dwarf_frame_buffer; |
| 1892 | |
| 1893 | /* Check whether we've already read it. */ |
| 1894 | if (find_cie (cie_table, cie_pointer)) |
| 1895 | return end; |
| 1896 | |
| 1897 | cie = (struct dwarf2_cie *) |
| 1898 | obstack_alloc (&unit->objfile->objfile_obstack, |
| 1899 | sizeof (struct dwarf2_cie)); |
| 1900 | cie->initial_instructions = NULL; |
| 1901 | cie->cie_pointer = cie_pointer; |
| 1902 | |
| 1903 | /* The encoding for FDE's in a normal .debug_frame section |
| 1904 | depends on the target address size. */ |
| 1905 | cie->encoding = DW_EH_PE_absptr; |
| 1906 | |
| 1907 | /* We'll determine the final value later, but we need to |
| 1908 | initialize it conservatively. */ |
| 1909 | cie->signal_frame = 0; |
| 1910 | |
| 1911 | /* Check version number. */ |
| 1912 | cie_version = read_1_byte (unit->abfd, buf); |
| 1913 | if (cie_version != 1 && cie_version != 3 && cie_version != 4) |
| 1914 | return NULL; |
| 1915 | cie->version = cie_version; |
| 1916 | buf += 1; |
| 1917 | |
| 1918 | /* Interpret the interesting bits of the augmentation. */ |
| 1919 | cie->augmentation = augmentation = (char *) buf; |
| 1920 | buf += (strlen (augmentation) + 1); |
| 1921 | |
| 1922 | /* Ignore armcc augmentations. We only use them for quirks, |
| 1923 | and that doesn't happen until later. */ |
| 1924 | if (strncmp (augmentation, "armcc", 5) == 0) |
| 1925 | augmentation += strlen (augmentation); |
| 1926 | |
| 1927 | /* The GCC 2.x "eh" augmentation has a pointer immediately |
| 1928 | following the augmentation string, so it must be handled |
| 1929 | first. */ |
| 1930 | if (augmentation[0] == 'e' && augmentation[1] == 'h') |
| 1931 | { |
| 1932 | /* Skip. */ |
| 1933 | buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT; |
| 1934 | augmentation += 2; |
| 1935 | } |
| 1936 | |
| 1937 | if (cie->version >= 4) |
| 1938 | { |
| 1939 | /* FIXME: check that this is the same as from the CU header. */ |
| 1940 | cie->addr_size = read_1_byte (unit->abfd, buf); |
| 1941 | ++buf; |
| 1942 | cie->segment_size = read_1_byte (unit->abfd, buf); |
| 1943 | ++buf; |
| 1944 | } |
| 1945 | else |
| 1946 | { |
| 1947 | cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch); |
| 1948 | cie->segment_size = 0; |
| 1949 | } |
| 1950 | /* Address values in .eh_frame sections are defined to have the |
| 1951 | target's pointer size. Watchout: This breaks frame info for |
| 1952 | targets with pointer size < address size, unless a .debug_frame |
| 1953 | section exists as well. */ |
| 1954 | if (eh_frame_p) |
| 1955 | cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT; |
| 1956 | else |
| 1957 | cie->ptr_size = cie->addr_size; |
| 1958 | |
| 1959 | buf = gdb_read_uleb128 (buf, end, &uleb128); |
| 1960 | if (buf == NULL) |
| 1961 | return NULL; |
| 1962 | cie->code_alignment_factor = uleb128; |
| 1963 | |
| 1964 | buf = gdb_read_sleb128 (buf, end, &sleb128); |
| 1965 | if (buf == NULL) |
| 1966 | return NULL; |
| 1967 | cie->data_alignment_factor = sleb128; |
| 1968 | |
| 1969 | if (cie_version == 1) |
| 1970 | { |
| 1971 | cie->return_address_register = read_1_byte (unit->abfd, buf); |
| 1972 | ++buf; |
| 1973 | } |
| 1974 | else |
| 1975 | { |
| 1976 | buf = gdb_read_uleb128 (buf, end, &uleb128); |
| 1977 | if (buf == NULL) |
| 1978 | return NULL; |
| 1979 | cie->return_address_register = uleb128; |
| 1980 | } |
| 1981 | |
| 1982 | cie->return_address_register |
| 1983 | = dwarf2_frame_adjust_regnum (gdbarch, |
| 1984 | cie->return_address_register, |
| 1985 | eh_frame_p); |
| 1986 | |
| 1987 | cie->saw_z_augmentation = (*augmentation == 'z'); |
| 1988 | if (cie->saw_z_augmentation) |
| 1989 | { |
| 1990 | uint64_t length; |
| 1991 | |
| 1992 | buf = gdb_read_uleb128 (buf, end, &length); |
| 1993 | if (buf == NULL) |
| 1994 | return NULL; |
| 1995 | cie->initial_instructions = buf + length; |
| 1996 | augmentation++; |
| 1997 | } |
| 1998 | |
| 1999 | while (*augmentation) |
| 2000 | { |
| 2001 | /* "L" indicates a byte showing how the LSDA pointer is encoded. */ |
| 2002 | if (*augmentation == 'L') |
| 2003 | { |
| 2004 | /* Skip. */ |
| 2005 | buf++; |
| 2006 | augmentation++; |
| 2007 | } |
| 2008 | |
| 2009 | /* "R" indicates a byte indicating how FDE addresses are encoded. */ |
| 2010 | else if (*augmentation == 'R') |
| 2011 | { |
| 2012 | cie->encoding = *buf++; |
| 2013 | augmentation++; |
| 2014 | } |
| 2015 | |
| 2016 | /* "P" indicates a personality routine in the CIE augmentation. */ |
| 2017 | else if (*augmentation == 'P') |
| 2018 | { |
| 2019 | /* Skip. Avoid indirection since we throw away the result. */ |
| 2020 | gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect; |
| 2021 | read_encoded_value (unit, encoding, cie->ptr_size, |
| 2022 | buf, &bytes_read, 0); |
| 2023 | buf += bytes_read; |
| 2024 | augmentation++; |
| 2025 | } |
| 2026 | |
| 2027 | /* "S" indicates a signal frame, such that the return |
| 2028 | address must not be decremented to locate the call frame |
| 2029 | info for the previous frame; it might even be the first |
| 2030 | instruction of a function, so decrementing it would take |
| 2031 | us to a different function. */ |
| 2032 | else if (*augmentation == 'S') |
| 2033 | { |
| 2034 | cie->signal_frame = 1; |
| 2035 | augmentation++; |
| 2036 | } |
| 2037 | |
| 2038 | /* Otherwise we have an unknown augmentation. Assume that either |
| 2039 | there is no augmentation data, or we saw a 'z' prefix. */ |
| 2040 | else |
| 2041 | { |
| 2042 | if (cie->initial_instructions) |
| 2043 | buf = cie->initial_instructions; |
| 2044 | break; |
| 2045 | } |
| 2046 | } |
| 2047 | |
| 2048 | cie->initial_instructions = buf; |
| 2049 | cie->end = end; |
| 2050 | cie->unit = unit; |
| 2051 | |
| 2052 | add_cie (cie_table, cie); |
| 2053 | } |
| 2054 | else |
| 2055 | { |
| 2056 | /* This is a FDE. */ |
| 2057 | struct dwarf2_fde *fde; |
| 2058 | |
| 2059 | /* Check that an FDE was expected. */ |
| 2060 | if ((entry_type & EH_FDE_TYPE_ID) == 0) |
| 2061 | error (_("Found an FDE when not expecting it.")); |
| 2062 | |
| 2063 | /* In an .eh_frame section, the CIE pointer is the delta between the |
| 2064 | address within the FDE where the CIE pointer is stored and the |
| 2065 | address of the CIE. Convert it to an offset into the .eh_frame |
| 2066 | section. */ |
| 2067 | if (eh_frame_p) |
| 2068 | { |
| 2069 | cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer; |
| 2070 | cie_pointer -= (dwarf64_p ? 8 : 4); |
| 2071 | } |
| 2072 | |
| 2073 | /* In either case, validate the result is still within the section. */ |
| 2074 | if (cie_pointer >= unit->dwarf_frame_size) |
| 2075 | return NULL; |
| 2076 | |
| 2077 | fde = (struct dwarf2_fde *) |
| 2078 | obstack_alloc (&unit->objfile->objfile_obstack, |
| 2079 | sizeof (struct dwarf2_fde)); |
| 2080 | fde->cie = find_cie (cie_table, cie_pointer); |
| 2081 | if (fde->cie == NULL) |
| 2082 | { |
| 2083 | decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer, |
| 2084 | eh_frame_p, cie_table, fde_table, |
| 2085 | EH_CIE_TYPE_ID); |
| 2086 | fde->cie = find_cie (cie_table, cie_pointer); |
| 2087 | } |
| 2088 | |
| 2089 | gdb_assert (fde->cie != NULL); |
| 2090 | |
| 2091 | fde->initial_location = |
| 2092 | read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size, |
| 2093 | buf, &bytes_read, 0); |
| 2094 | buf += bytes_read; |
| 2095 | |
| 2096 | fde->address_range = |
| 2097 | read_encoded_value (unit, fde->cie->encoding & 0x0f, |
| 2098 | fde->cie->ptr_size, buf, &bytes_read, 0); |
| 2099 | buf += bytes_read; |
| 2100 | |
| 2101 | /* A 'z' augmentation in the CIE implies the presence of an |
| 2102 | augmentation field in the FDE as well. The only thing known |
| 2103 | to be in here at present is the LSDA entry for EH. So we |
| 2104 | can skip the whole thing. */ |
| 2105 | if (fde->cie->saw_z_augmentation) |
| 2106 | { |
| 2107 | uint64_t length; |
| 2108 | |
| 2109 | buf = gdb_read_uleb128 (buf, end, &length); |
| 2110 | if (buf == NULL) |
| 2111 | return NULL; |
| 2112 | buf += length; |
| 2113 | if (buf > end) |
| 2114 | return NULL; |
| 2115 | } |
| 2116 | |
| 2117 | fde->instructions = buf; |
| 2118 | fde->end = end; |
| 2119 | |
| 2120 | fde->eh_frame_p = eh_frame_p; |
| 2121 | |
| 2122 | add_fde (fde_table, fde); |
| 2123 | } |
| 2124 | |
| 2125 | return end; |
| 2126 | } |
| 2127 | |
| 2128 | /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we |
| 2129 | expect an FDE or a CIE. */ |
| 2130 | |
| 2131 | static const gdb_byte * |
| 2132 | decode_frame_entry (struct comp_unit *unit, const gdb_byte *start, |
| 2133 | int eh_frame_p, |
| 2134 | struct dwarf2_cie_table *cie_table, |
| 2135 | struct dwarf2_fde_table *fde_table, |
| 2136 | enum eh_frame_type entry_type) |
| 2137 | { |
| 2138 | enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE; |
| 2139 | const gdb_byte *ret; |
| 2140 | ptrdiff_t start_offset; |
| 2141 | |
| 2142 | while (1) |
| 2143 | { |
| 2144 | ret = decode_frame_entry_1 (unit, start, eh_frame_p, |
| 2145 | cie_table, fde_table, entry_type); |
| 2146 | if (ret != NULL) |
| 2147 | break; |
| 2148 | |
| 2149 | /* We have corrupt input data of some form. */ |
| 2150 | |
| 2151 | /* ??? Try, weakly, to work around compiler/assembler/linker bugs |
| 2152 | and mismatches wrt padding and alignment of debug sections. */ |
| 2153 | /* Note that there is no requirement in the standard for any |
| 2154 | alignment at all in the frame unwind sections. Testing for |
| 2155 | alignment before trying to interpret data would be incorrect. |
| 2156 | |
| 2157 | However, GCC traditionally arranged for frame sections to be |
| 2158 | sized such that the FDE length and CIE fields happen to be |
| 2159 | aligned (in theory, for performance). This, unfortunately, |
| 2160 | was done with .align directives, which had the side effect of |
| 2161 | forcing the section to be aligned by the linker. |
| 2162 | |
| 2163 | This becomes a problem when you have some other producer that |
| 2164 | creates frame sections that are not as strictly aligned. That |
| 2165 | produces a hole in the frame info that gets filled by the |
| 2166 | linker with zeros. |
| 2167 | |
| 2168 | The GCC behaviour is arguably a bug, but it's effectively now |
| 2169 | part of the ABI, so we're now stuck with it, at least at the |
| 2170 | object file level. A smart linker may decide, in the process |
| 2171 | of compressing duplicate CIE information, that it can rewrite |
| 2172 | the entire output section without this extra padding. */ |
| 2173 | |
| 2174 | start_offset = start - unit->dwarf_frame_buffer; |
| 2175 | if (workaround < ALIGN4 && (start_offset & 3) != 0) |
| 2176 | { |
| 2177 | start += 4 - (start_offset & 3); |
| 2178 | workaround = ALIGN4; |
| 2179 | continue; |
| 2180 | } |
| 2181 | if (workaround < ALIGN8 && (start_offset & 7) != 0) |
| 2182 | { |
| 2183 | start += 8 - (start_offset & 7); |
| 2184 | workaround = ALIGN8; |
| 2185 | continue; |
| 2186 | } |
| 2187 | |
| 2188 | /* Nothing left to try. Arrange to return as if we've consumed |
| 2189 | the entire input section. Hopefully we'll get valid info from |
| 2190 | the other of .debug_frame/.eh_frame. */ |
| 2191 | workaround = FAIL; |
| 2192 | ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size; |
| 2193 | break; |
| 2194 | } |
| 2195 | |
| 2196 | switch (workaround) |
| 2197 | { |
| 2198 | case NONE: |
| 2199 | break; |
| 2200 | |
| 2201 | case ALIGN4: |
| 2202 | complaint (&symfile_complaints, _("\ |
| 2203 | Corrupt data in %s:%s; align 4 workaround apparently succeeded"), |
| 2204 | unit->dwarf_frame_section->owner->filename, |
| 2205 | unit->dwarf_frame_section->name); |
| 2206 | break; |
| 2207 | |
| 2208 | case ALIGN8: |
| 2209 | complaint (&symfile_complaints, _("\ |
| 2210 | Corrupt data in %s:%s; align 8 workaround apparently succeeded"), |
| 2211 | unit->dwarf_frame_section->owner->filename, |
| 2212 | unit->dwarf_frame_section->name); |
| 2213 | break; |
| 2214 | |
| 2215 | default: |
| 2216 | complaint (&symfile_complaints, |
| 2217 | _("Corrupt data in %s:%s"), |
| 2218 | unit->dwarf_frame_section->owner->filename, |
| 2219 | unit->dwarf_frame_section->name); |
| 2220 | break; |
| 2221 | } |
| 2222 | |
| 2223 | return ret; |
| 2224 | } |
| 2225 | \f |
| 2226 | static int |
| 2227 | qsort_fde_cmp (const void *a, const void *b) |
| 2228 | { |
| 2229 | struct dwarf2_fde *aa = *(struct dwarf2_fde **)a; |
| 2230 | struct dwarf2_fde *bb = *(struct dwarf2_fde **)b; |
| 2231 | |
| 2232 | if (aa->initial_location == bb->initial_location) |
| 2233 | { |
| 2234 | if (aa->address_range != bb->address_range |
| 2235 | && aa->eh_frame_p == 0 && bb->eh_frame_p == 0) |
| 2236 | /* Linker bug, e.g. gold/10400. |
| 2237 | Work around it by keeping stable sort order. */ |
| 2238 | return (a < b) ? -1 : 1; |
| 2239 | else |
| 2240 | /* Put eh_frame entries after debug_frame ones. */ |
| 2241 | return aa->eh_frame_p - bb->eh_frame_p; |
| 2242 | } |
| 2243 | |
| 2244 | return (aa->initial_location < bb->initial_location) ? -1 : 1; |
| 2245 | } |
| 2246 | |
| 2247 | void |
| 2248 | dwarf2_build_frame_info (struct objfile *objfile) |
| 2249 | { |
| 2250 | struct comp_unit *unit; |
| 2251 | const gdb_byte *frame_ptr; |
| 2252 | struct dwarf2_cie_table cie_table; |
| 2253 | struct dwarf2_fde_table fde_table; |
| 2254 | struct dwarf2_fde_table *fde_table2; |
| 2255 | volatile struct gdb_exception e; |
| 2256 | |
| 2257 | cie_table.num_entries = 0; |
| 2258 | cie_table.entries = NULL; |
| 2259 | |
| 2260 | fde_table.num_entries = 0; |
| 2261 | fde_table.entries = NULL; |
| 2262 | |
| 2263 | /* Build a minimal decoding of the DWARF2 compilation unit. */ |
| 2264 | unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack, |
| 2265 | sizeof (struct comp_unit)); |
| 2266 | unit->abfd = objfile->obfd; |
| 2267 | unit->objfile = objfile; |
| 2268 | unit->dbase = 0; |
| 2269 | unit->tbase = 0; |
| 2270 | |
| 2271 | if (objfile->separate_debug_objfile_backlink == NULL) |
| 2272 | { |
| 2273 | /* Do not read .eh_frame from separate file as they must be also |
| 2274 | present in the main file. */ |
| 2275 | dwarf2_get_section_info (objfile, DWARF2_EH_FRAME, |
| 2276 | &unit->dwarf_frame_section, |
| 2277 | &unit->dwarf_frame_buffer, |
| 2278 | &unit->dwarf_frame_size); |
| 2279 | if (unit->dwarf_frame_size) |
| 2280 | { |
| 2281 | asection *got, *txt; |
| 2282 | |
| 2283 | /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base |
| 2284 | that is used for the i386/amd64 target, which currently is |
| 2285 | the only target in GCC that supports/uses the |
| 2286 | DW_EH_PE_datarel encoding. */ |
| 2287 | got = bfd_get_section_by_name (unit->abfd, ".got"); |
| 2288 | if (got) |
| 2289 | unit->dbase = got->vma; |
| 2290 | |
| 2291 | /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64 |
| 2292 | so far. */ |
| 2293 | txt = bfd_get_section_by_name (unit->abfd, ".text"); |
| 2294 | if (txt) |
| 2295 | unit->tbase = txt->vma; |
| 2296 | |
| 2297 | TRY_CATCH (e, RETURN_MASK_ERROR) |
| 2298 | { |
| 2299 | frame_ptr = unit->dwarf_frame_buffer; |
| 2300 | while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 2301 | frame_ptr = decode_frame_entry (unit, frame_ptr, 1, |
| 2302 | &cie_table, &fde_table, |
| 2303 | EH_CIE_OR_FDE_TYPE_ID); |
| 2304 | } |
| 2305 | |
| 2306 | if (e.reason < 0) |
| 2307 | { |
| 2308 | warning (_("skipping .eh_frame info of %s: %s"), |
| 2309 | objfile->name, e.message); |
| 2310 | |
| 2311 | if (fde_table.num_entries != 0) |
| 2312 | { |
| 2313 | xfree (fde_table.entries); |
| 2314 | fde_table.entries = NULL; |
| 2315 | fde_table.num_entries = 0; |
| 2316 | } |
| 2317 | /* The cie_table is discarded by the next if. */ |
| 2318 | } |
| 2319 | |
| 2320 | if (cie_table.num_entries != 0) |
| 2321 | { |
| 2322 | /* Reinit cie_table: debug_frame has different CIEs. */ |
| 2323 | xfree (cie_table.entries); |
| 2324 | cie_table.num_entries = 0; |
| 2325 | cie_table.entries = NULL; |
| 2326 | } |
| 2327 | } |
| 2328 | } |
| 2329 | |
| 2330 | dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME, |
| 2331 | &unit->dwarf_frame_section, |
| 2332 | &unit->dwarf_frame_buffer, |
| 2333 | &unit->dwarf_frame_size); |
| 2334 | if (unit->dwarf_frame_size) |
| 2335 | { |
| 2336 | int num_old_fde_entries = fde_table.num_entries; |
| 2337 | |
| 2338 | TRY_CATCH (e, RETURN_MASK_ERROR) |
| 2339 | { |
| 2340 | frame_ptr = unit->dwarf_frame_buffer; |
| 2341 | while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 2342 | frame_ptr = decode_frame_entry (unit, frame_ptr, 0, |
| 2343 | &cie_table, &fde_table, |
| 2344 | EH_CIE_OR_FDE_TYPE_ID); |
| 2345 | } |
| 2346 | if (e.reason < 0) |
| 2347 | { |
| 2348 | warning (_("skipping .debug_frame info of %s: %s"), |
| 2349 | objfile->name, e.message); |
| 2350 | |
| 2351 | if (fde_table.num_entries != 0) |
| 2352 | { |
| 2353 | fde_table.num_entries = num_old_fde_entries; |
| 2354 | if (num_old_fde_entries == 0) |
| 2355 | { |
| 2356 | xfree (fde_table.entries); |
| 2357 | fde_table.entries = NULL; |
| 2358 | } |
| 2359 | else |
| 2360 | { |
| 2361 | fde_table.entries = xrealloc (fde_table.entries, |
| 2362 | fde_table.num_entries * |
| 2363 | sizeof (fde_table.entries[0])); |
| 2364 | } |
| 2365 | } |
| 2366 | fde_table.num_entries = num_old_fde_entries; |
| 2367 | /* The cie_table is discarded by the next if. */ |
| 2368 | } |
| 2369 | } |
| 2370 | |
| 2371 | /* Discard the cie_table, it is no longer needed. */ |
| 2372 | if (cie_table.num_entries != 0) |
| 2373 | { |
| 2374 | xfree (cie_table.entries); |
| 2375 | cie_table.entries = NULL; /* Paranoia. */ |
| 2376 | cie_table.num_entries = 0; /* Paranoia. */ |
| 2377 | } |
| 2378 | |
| 2379 | /* Copy fde_table to obstack: it is needed at runtime. */ |
| 2380 | fde_table2 = (struct dwarf2_fde_table *) |
| 2381 | obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2)); |
| 2382 | |
| 2383 | if (fde_table.num_entries == 0) |
| 2384 | { |
| 2385 | fde_table2->entries = NULL; |
| 2386 | fde_table2->num_entries = 0; |
| 2387 | } |
| 2388 | else |
| 2389 | { |
| 2390 | struct dwarf2_fde *fde_prev = NULL; |
| 2391 | struct dwarf2_fde *first_non_zero_fde = NULL; |
| 2392 | int i; |
| 2393 | |
| 2394 | /* Prepare FDE table for lookups. */ |
| 2395 | qsort (fde_table.entries, fde_table.num_entries, |
| 2396 | sizeof (fde_table.entries[0]), qsort_fde_cmp); |
| 2397 | |
| 2398 | /* Check for leftovers from --gc-sections. The GNU linker sets |
| 2399 | the relevant symbols to zero, but doesn't zero the FDE *end* |
| 2400 | ranges because there's no relocation there. It's (offset, |
| 2401 | length), not (start, end). On targets where address zero is |
| 2402 | just another valid address this can be a problem, since the |
| 2403 | FDEs appear to be non-empty in the output --- we could pick |
| 2404 | out the wrong FDE. To work around this, when overlaps are |
| 2405 | detected, we prefer FDEs that do not start at zero. |
| 2406 | |
| 2407 | Start by finding the first FDE with non-zero start. Below |
| 2408 | we'll discard all FDEs that start at zero and overlap this |
| 2409 | one. */ |
| 2410 | for (i = 0; i < fde_table.num_entries; i++) |
| 2411 | { |
| 2412 | struct dwarf2_fde *fde = fde_table.entries[i]; |
| 2413 | |
| 2414 | if (fde->initial_location != 0) |
| 2415 | { |
| 2416 | first_non_zero_fde = fde; |
| 2417 | break; |
| 2418 | } |
| 2419 | } |
| 2420 | |
| 2421 | /* Since we'll be doing bsearch, squeeze out identical (except |
| 2422 | for eh_frame_p) fde entries so bsearch result is predictable. |
| 2423 | Also discard leftovers from --gc-sections. */ |
| 2424 | fde_table2->num_entries = 0; |
| 2425 | for (i = 0; i < fde_table.num_entries; i++) |
| 2426 | { |
| 2427 | struct dwarf2_fde *fde = fde_table.entries[i]; |
| 2428 | |
| 2429 | if (fde->initial_location == 0 |
| 2430 | && first_non_zero_fde != NULL |
| 2431 | && (first_non_zero_fde->initial_location |
| 2432 | < fde->initial_location + fde->address_range)) |
| 2433 | continue; |
| 2434 | |
| 2435 | if (fde_prev != NULL |
| 2436 | && fde_prev->initial_location == fde->initial_location) |
| 2437 | continue; |
| 2438 | |
| 2439 | obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i], |
| 2440 | sizeof (fde_table.entries[0])); |
| 2441 | ++fde_table2->num_entries; |
| 2442 | fde_prev = fde; |
| 2443 | } |
| 2444 | fde_table2->entries = obstack_finish (&objfile->objfile_obstack); |
| 2445 | |
| 2446 | /* Discard the original fde_table. */ |
| 2447 | xfree (fde_table.entries); |
| 2448 | } |
| 2449 | |
| 2450 | set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2); |
| 2451 | } |
| 2452 | |
| 2453 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 2454 | void _initialize_dwarf2_frame (void); |
| 2455 | |
| 2456 | void |
| 2457 | _initialize_dwarf2_frame (void) |
| 2458 | { |
| 2459 | dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init); |
| 2460 | dwarf2_frame_objfile_data = register_objfile_data (); |
| 2461 | } |