| 1 | /* Frame unwinder for frames with DWARF Call Frame Information. |
| 2 | |
| 3 | Copyright (C) 2003-2020 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 "dwarf2/expr.h" |
| 24 | #include "dwarf2.h" |
| 25 | #include "dwarf2/leb.h" |
| 26 | #include "frame.h" |
| 27 | #include "frame-base.h" |
| 28 | #include "frame-unwind.h" |
| 29 | #include "gdbcore.h" |
| 30 | #include "gdbtypes.h" |
| 31 | #include "symtab.h" |
| 32 | #include "objfiles.h" |
| 33 | #include "regcache.h" |
| 34 | #include "value.h" |
| 35 | #include "record.h" |
| 36 | |
| 37 | #include "complaints.h" |
| 38 | #include "dwarf2/frame.h" |
| 39 | #include "dwarf2/read.h" |
| 40 | #include "ax.h" |
| 41 | #include "dwarf2/loc.h" |
| 42 | #include "dwarf2/frame-tailcall.h" |
| 43 | #include "gdbsupport/gdb_binary_search.h" |
| 44 | #if GDB_SELF_TEST |
| 45 | #include "gdbsupport/selftest.h" |
| 46 | #include "selftest-arch.h" |
| 47 | #endif |
| 48 | #include <unordered_map> |
| 49 | |
| 50 | #include <algorithm> |
| 51 | |
| 52 | struct comp_unit; |
| 53 | |
| 54 | /* Call Frame Information (CFI). */ |
| 55 | |
| 56 | /* Common Information Entry (CIE). */ |
| 57 | |
| 58 | struct dwarf2_cie |
| 59 | { |
| 60 | /* Computation Unit for this CIE. */ |
| 61 | struct comp_unit *unit; |
| 62 | |
| 63 | /* Offset into the .debug_frame section where this CIE was found. |
| 64 | Used to identify this CIE. */ |
| 65 | ULONGEST cie_pointer; |
| 66 | |
| 67 | /* Constant that is factored out of all advance location |
| 68 | instructions. */ |
| 69 | ULONGEST code_alignment_factor; |
| 70 | |
| 71 | /* Constants that is factored out of all offset instructions. */ |
| 72 | LONGEST data_alignment_factor; |
| 73 | |
| 74 | /* Return address column. */ |
| 75 | ULONGEST return_address_register; |
| 76 | |
| 77 | /* Instruction sequence to initialize a register set. */ |
| 78 | const gdb_byte *initial_instructions; |
| 79 | const gdb_byte *end; |
| 80 | |
| 81 | /* Saved augmentation, in case it's needed later. */ |
| 82 | char *augmentation; |
| 83 | |
| 84 | /* Encoding of addresses. */ |
| 85 | gdb_byte encoding; |
| 86 | |
| 87 | /* Target address size in bytes. */ |
| 88 | int addr_size; |
| 89 | |
| 90 | /* Target pointer size in bytes. */ |
| 91 | int ptr_size; |
| 92 | |
| 93 | /* True if a 'z' augmentation existed. */ |
| 94 | unsigned char saw_z_augmentation; |
| 95 | |
| 96 | /* True if an 'S' augmentation existed. */ |
| 97 | unsigned char signal_frame; |
| 98 | |
| 99 | /* The version recorded in the CIE. */ |
| 100 | unsigned char version; |
| 101 | |
| 102 | /* The segment size. */ |
| 103 | unsigned char segment_size; |
| 104 | }; |
| 105 | |
| 106 | /* The CIE table is used to find CIEs during parsing, but then |
| 107 | discarded. It maps from the CIE's offset to the CIE. */ |
| 108 | typedef std::unordered_map<ULONGEST, dwarf2_cie *> dwarf2_cie_table; |
| 109 | |
| 110 | /* Frame Description Entry (FDE). */ |
| 111 | |
| 112 | struct dwarf2_fde |
| 113 | { |
| 114 | /* CIE for this FDE. */ |
| 115 | struct dwarf2_cie *cie; |
| 116 | |
| 117 | /* First location associated with this FDE. */ |
| 118 | CORE_ADDR initial_location; |
| 119 | |
| 120 | /* Number of bytes of program instructions described by this FDE. */ |
| 121 | CORE_ADDR address_range; |
| 122 | |
| 123 | /* Instruction sequence. */ |
| 124 | const gdb_byte *instructions; |
| 125 | const gdb_byte *end; |
| 126 | |
| 127 | /* True if this FDE is read from a .eh_frame instead of a .debug_frame |
| 128 | section. */ |
| 129 | unsigned char eh_frame_p; |
| 130 | }; |
| 131 | |
| 132 | typedef std::vector<dwarf2_fde *> dwarf2_fde_table; |
| 133 | |
| 134 | /* A minimal decoding of DWARF2 compilation units. We only decode |
| 135 | what's needed to get to the call frame information. */ |
| 136 | |
| 137 | struct comp_unit |
| 138 | { |
| 139 | comp_unit (struct objfile *objf) |
| 140 | : abfd (objf->obfd) |
| 141 | { |
| 142 | } |
| 143 | |
| 144 | /* Keep the bfd convenient. */ |
| 145 | bfd *abfd; |
| 146 | |
| 147 | /* Pointer to the .debug_frame section loaded into memory. */ |
| 148 | const gdb_byte *dwarf_frame_buffer = nullptr; |
| 149 | |
| 150 | /* Length of the loaded .debug_frame section. */ |
| 151 | bfd_size_type dwarf_frame_size = 0; |
| 152 | |
| 153 | /* Pointer to the .debug_frame section. */ |
| 154 | asection *dwarf_frame_section = nullptr; |
| 155 | |
| 156 | /* Base for DW_EH_PE_datarel encodings. */ |
| 157 | bfd_vma dbase = 0; |
| 158 | |
| 159 | /* Base for DW_EH_PE_textrel encodings. */ |
| 160 | bfd_vma tbase = 0; |
| 161 | |
| 162 | /* The FDE table. */ |
| 163 | dwarf2_fde_table fde_table; |
| 164 | |
| 165 | /* Hold data used by this module. */ |
| 166 | auto_obstack obstack; |
| 167 | }; |
| 168 | |
| 169 | static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc, |
| 170 | CORE_ADDR *out_offset); |
| 171 | |
| 172 | static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum, |
| 173 | int eh_frame_p); |
| 174 | |
| 175 | static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding, |
| 176 | int ptr_len, const gdb_byte *buf, |
| 177 | unsigned int *bytes_read_ptr, |
| 178 | CORE_ADDR func_base); |
| 179 | \f |
| 180 | |
| 181 | /* See dwarf2-frame.h. */ |
| 182 | bool dwarf2_frame_unwinders_enabled_p = true; |
| 183 | |
| 184 | /* Store the length the expression for the CFA in the `cfa_reg' field, |
| 185 | which is unused in that case. */ |
| 186 | #define cfa_exp_len cfa_reg |
| 187 | |
| 188 | dwarf2_frame_state::dwarf2_frame_state (CORE_ADDR pc_, struct dwarf2_cie *cie) |
| 189 | : pc (pc_), data_align (cie->data_alignment_factor), |
| 190 | code_align (cie->code_alignment_factor), |
| 191 | retaddr_column (cie->return_address_register) |
| 192 | { |
| 193 | } |
| 194 | \f |
| 195 | |
| 196 | /* Helper functions for execute_stack_op. */ |
| 197 | |
| 198 | static CORE_ADDR |
| 199 | read_addr_from_reg (struct frame_info *this_frame, int reg) |
| 200 | { |
| 201 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 202 | int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg); |
| 203 | |
| 204 | return address_from_register (regnum, this_frame); |
| 205 | } |
| 206 | |
| 207 | /* Execute the required actions for both the DW_CFA_restore and |
| 208 | DW_CFA_restore_extended instructions. */ |
| 209 | static void |
| 210 | dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num, |
| 211 | struct dwarf2_frame_state *fs, int eh_frame_p) |
| 212 | { |
| 213 | ULONGEST reg; |
| 214 | |
| 215 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p); |
| 216 | fs->regs.alloc_regs (reg + 1); |
| 217 | |
| 218 | /* Check if this register was explicitly initialized in the |
| 219 | CIE initial instructions. If not, default the rule to |
| 220 | UNSPECIFIED. */ |
| 221 | if (reg < fs->initial.reg.size ()) |
| 222 | fs->regs.reg[reg] = fs->initial.reg[reg]; |
| 223 | else |
| 224 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED; |
| 225 | |
| 226 | if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 227 | { |
| 228 | int regnum = dwarf_reg_to_regnum (gdbarch, reg); |
| 229 | |
| 230 | complaint (_("\ |
| 231 | incomplete CFI data; DW_CFA_restore unspecified\n\ |
| 232 | register %s (#%d) at %s"), |
| 233 | gdbarch_register_name (gdbarch, regnum), regnum, |
| 234 | paddress (gdbarch, fs->pc)); |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | class dwarf_expr_executor : public dwarf_expr_context |
| 239 | { |
| 240 | public: |
| 241 | |
| 242 | struct frame_info *this_frame; |
| 243 | |
| 244 | CORE_ADDR read_addr_from_reg (int reg) override |
| 245 | { |
| 246 | return ::read_addr_from_reg (this_frame, reg); |
| 247 | } |
| 248 | |
| 249 | struct value *get_reg_value (struct type *type, int reg) override |
| 250 | { |
| 251 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 252 | int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg); |
| 253 | |
| 254 | return value_from_register (type, regnum, this_frame); |
| 255 | } |
| 256 | |
| 257 | void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override |
| 258 | { |
| 259 | read_memory (addr, buf, len); |
| 260 | } |
| 261 | |
| 262 | void get_frame_base (const gdb_byte **start, size_t *length) override |
| 263 | { |
| 264 | invalid ("DW_OP_fbreg"); |
| 265 | } |
| 266 | |
| 267 | void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind, |
| 268 | union call_site_parameter_u kind_u, |
| 269 | int deref_size) override |
| 270 | { |
| 271 | invalid ("DW_OP_entry_value"); |
| 272 | } |
| 273 | |
| 274 | CORE_ADDR get_object_address () override |
| 275 | { |
| 276 | invalid ("DW_OP_push_object_address"); |
| 277 | } |
| 278 | |
| 279 | CORE_ADDR get_frame_cfa () override |
| 280 | { |
| 281 | invalid ("DW_OP_call_frame_cfa"); |
| 282 | } |
| 283 | |
| 284 | CORE_ADDR get_tls_address (CORE_ADDR offset) override |
| 285 | { |
| 286 | invalid ("DW_OP_form_tls_address"); |
| 287 | } |
| 288 | |
| 289 | void dwarf_call (cu_offset die_offset) override |
| 290 | { |
| 291 | invalid ("DW_OP_call*"); |
| 292 | } |
| 293 | |
| 294 | struct value *dwarf_variable_value (sect_offset sect_off) override |
| 295 | { |
| 296 | invalid ("DW_OP_GNU_variable_value"); |
| 297 | } |
| 298 | |
| 299 | CORE_ADDR get_addr_index (unsigned int index) override |
| 300 | { |
| 301 | invalid ("DW_OP_addrx or DW_OP_GNU_addr_index"); |
| 302 | } |
| 303 | |
| 304 | private: |
| 305 | |
| 306 | void invalid (const char *op) ATTRIBUTE_NORETURN |
| 307 | { |
| 308 | error (_("%s is invalid in this context"), op); |
| 309 | } |
| 310 | }; |
| 311 | |
| 312 | static CORE_ADDR |
| 313 | execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size, |
| 314 | CORE_ADDR offset, struct frame_info *this_frame, |
| 315 | CORE_ADDR initial, int initial_in_stack_memory) |
| 316 | { |
| 317 | CORE_ADDR result; |
| 318 | |
| 319 | dwarf_expr_executor ctx; |
| 320 | scoped_value_mark free_values; |
| 321 | |
| 322 | ctx.this_frame = this_frame; |
| 323 | ctx.gdbarch = get_frame_arch (this_frame); |
| 324 | ctx.addr_size = addr_size; |
| 325 | ctx.ref_addr_size = -1; |
| 326 | ctx.offset = offset; |
| 327 | |
| 328 | ctx.push_address (initial, initial_in_stack_memory); |
| 329 | ctx.eval (exp, len); |
| 330 | |
| 331 | if (ctx.location == DWARF_VALUE_MEMORY) |
| 332 | result = ctx.fetch_address (0); |
| 333 | else if (ctx.location == DWARF_VALUE_REGISTER) |
| 334 | result = ctx.read_addr_from_reg (value_as_long (ctx.fetch (0))); |
| 335 | else |
| 336 | { |
| 337 | /* This is actually invalid DWARF, but if we ever do run across |
| 338 | it somehow, we might as well support it. So, instead, report |
| 339 | it as unimplemented. */ |
| 340 | error (_("\ |
| 341 | Not implemented: computing unwound register using explicit value operator")); |
| 342 | } |
| 343 | |
| 344 | return result; |
| 345 | } |
| 346 | \f |
| 347 | |
| 348 | /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior |
| 349 | PC. Modify FS state accordingly. Return current INSN_PTR where the |
| 350 | execution has stopped, one can resume it on the next call. */ |
| 351 | |
| 352 | static const gdb_byte * |
| 353 | execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr, |
| 354 | const gdb_byte *insn_end, struct gdbarch *gdbarch, |
| 355 | CORE_ADDR pc, struct dwarf2_frame_state *fs, |
| 356 | CORE_ADDR text_offset) |
| 357 | { |
| 358 | int eh_frame_p = fde->eh_frame_p; |
| 359 | unsigned int bytes_read; |
| 360 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 361 | |
| 362 | while (insn_ptr < insn_end && fs->pc <= pc) |
| 363 | { |
| 364 | gdb_byte insn = *insn_ptr++; |
| 365 | uint64_t utmp, reg; |
| 366 | int64_t offset; |
| 367 | |
| 368 | if ((insn & 0xc0) == DW_CFA_advance_loc) |
| 369 | fs->pc += (insn & 0x3f) * fs->code_align; |
| 370 | else if ((insn & 0xc0) == DW_CFA_offset) |
| 371 | { |
| 372 | reg = insn & 0x3f; |
| 373 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 374 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 375 | offset = utmp * fs->data_align; |
| 376 | fs->regs.alloc_regs (reg + 1); |
| 377 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 378 | fs->regs.reg[reg].loc.offset = offset; |
| 379 | } |
| 380 | else if ((insn & 0xc0) == DW_CFA_restore) |
| 381 | { |
| 382 | reg = insn & 0x3f; |
| 383 | dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p); |
| 384 | } |
| 385 | else |
| 386 | { |
| 387 | switch (insn) |
| 388 | { |
| 389 | case DW_CFA_set_loc: |
| 390 | fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding, |
| 391 | fde->cie->ptr_size, insn_ptr, |
| 392 | &bytes_read, fde->initial_location); |
| 393 | /* Apply the text offset for relocatable objects. */ |
| 394 | fs->pc += text_offset; |
| 395 | insn_ptr += bytes_read; |
| 396 | break; |
| 397 | |
| 398 | case DW_CFA_advance_loc1: |
| 399 | utmp = extract_unsigned_integer (insn_ptr, 1, byte_order); |
| 400 | fs->pc += utmp * fs->code_align; |
| 401 | insn_ptr++; |
| 402 | break; |
| 403 | case DW_CFA_advance_loc2: |
| 404 | utmp = extract_unsigned_integer (insn_ptr, 2, byte_order); |
| 405 | fs->pc += utmp * fs->code_align; |
| 406 | insn_ptr += 2; |
| 407 | break; |
| 408 | case DW_CFA_advance_loc4: |
| 409 | utmp = extract_unsigned_integer (insn_ptr, 4, byte_order); |
| 410 | fs->pc += utmp * fs->code_align; |
| 411 | insn_ptr += 4; |
| 412 | break; |
| 413 | |
| 414 | case DW_CFA_offset_extended: |
| 415 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 416 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 417 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 418 | offset = utmp * fs->data_align; |
| 419 | fs->regs.alloc_regs (reg + 1); |
| 420 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 421 | fs->regs.reg[reg].loc.offset = offset; |
| 422 | break; |
| 423 | |
| 424 | case DW_CFA_restore_extended: |
| 425 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 426 | dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p); |
| 427 | break; |
| 428 | |
| 429 | case DW_CFA_undefined: |
| 430 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 431 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 432 | fs->regs.alloc_regs (reg + 1); |
| 433 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED; |
| 434 | break; |
| 435 | |
| 436 | case DW_CFA_same_value: |
| 437 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 438 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 439 | fs->regs.alloc_regs (reg + 1); |
| 440 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE; |
| 441 | break; |
| 442 | |
| 443 | case DW_CFA_register: |
| 444 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 445 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 446 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 447 | utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p); |
| 448 | fs->regs.alloc_regs (reg + 1); |
| 449 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG; |
| 450 | fs->regs.reg[reg].loc.reg = utmp; |
| 451 | break; |
| 452 | |
| 453 | case DW_CFA_remember_state: |
| 454 | { |
| 455 | struct dwarf2_frame_state_reg_info *new_rs; |
| 456 | |
| 457 | new_rs = new dwarf2_frame_state_reg_info (fs->regs); |
| 458 | fs->regs.prev = new_rs; |
| 459 | } |
| 460 | break; |
| 461 | |
| 462 | case DW_CFA_restore_state: |
| 463 | { |
| 464 | struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev; |
| 465 | |
| 466 | if (old_rs == NULL) |
| 467 | { |
| 468 | complaint (_("\ |
| 469 | bad CFI data; mismatched DW_CFA_restore_state at %s"), |
| 470 | paddress (gdbarch, fs->pc)); |
| 471 | } |
| 472 | else |
| 473 | fs->regs = std::move (*old_rs); |
| 474 | } |
| 475 | break; |
| 476 | |
| 477 | case DW_CFA_def_cfa: |
| 478 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 479 | fs->regs.cfa_reg = reg; |
| 480 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 481 | |
| 482 | if (fs->armcc_cfa_offsets_sf) |
| 483 | utmp *= fs->data_align; |
| 484 | |
| 485 | fs->regs.cfa_offset = utmp; |
| 486 | fs->regs.cfa_how = CFA_REG_OFFSET; |
| 487 | break; |
| 488 | |
| 489 | case DW_CFA_def_cfa_register: |
| 490 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 491 | fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg, |
| 492 | eh_frame_p); |
| 493 | fs->regs.cfa_how = CFA_REG_OFFSET; |
| 494 | break; |
| 495 | |
| 496 | case DW_CFA_def_cfa_offset: |
| 497 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 498 | |
| 499 | if (fs->armcc_cfa_offsets_sf) |
| 500 | utmp *= fs->data_align; |
| 501 | |
| 502 | fs->regs.cfa_offset = utmp; |
| 503 | /* cfa_how deliberately not set. */ |
| 504 | break; |
| 505 | |
| 506 | case DW_CFA_nop: |
| 507 | break; |
| 508 | |
| 509 | case DW_CFA_def_cfa_expression: |
| 510 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 511 | fs->regs.cfa_exp_len = utmp; |
| 512 | fs->regs.cfa_exp = insn_ptr; |
| 513 | fs->regs.cfa_how = CFA_EXP; |
| 514 | insn_ptr += fs->regs.cfa_exp_len; |
| 515 | break; |
| 516 | |
| 517 | case DW_CFA_expression: |
| 518 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 519 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 520 | fs->regs.alloc_regs (reg + 1); |
| 521 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 522 | fs->regs.reg[reg].loc.exp.start = insn_ptr; |
| 523 | fs->regs.reg[reg].loc.exp.len = utmp; |
| 524 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP; |
| 525 | insn_ptr += utmp; |
| 526 | break; |
| 527 | |
| 528 | case DW_CFA_offset_extended_sf: |
| 529 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 530 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 531 | insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset); |
| 532 | offset *= fs->data_align; |
| 533 | fs->regs.alloc_regs (reg + 1); |
| 534 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 535 | fs->regs.reg[reg].loc.offset = offset; |
| 536 | break; |
| 537 | |
| 538 | case DW_CFA_val_offset: |
| 539 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 540 | fs->regs.alloc_regs (reg + 1); |
| 541 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 542 | offset = utmp * fs->data_align; |
| 543 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET; |
| 544 | fs->regs.reg[reg].loc.offset = offset; |
| 545 | break; |
| 546 | |
| 547 | case DW_CFA_val_offset_sf: |
| 548 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 549 | fs->regs.alloc_regs (reg + 1); |
| 550 | insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset); |
| 551 | offset *= fs->data_align; |
| 552 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET; |
| 553 | fs->regs.reg[reg].loc.offset = offset; |
| 554 | break; |
| 555 | |
| 556 | case DW_CFA_val_expression: |
| 557 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 558 | fs->regs.alloc_regs (reg + 1); |
| 559 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 560 | fs->regs.reg[reg].loc.exp.start = insn_ptr; |
| 561 | fs->regs.reg[reg].loc.exp.len = utmp; |
| 562 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP; |
| 563 | insn_ptr += utmp; |
| 564 | break; |
| 565 | |
| 566 | case DW_CFA_def_cfa_sf: |
| 567 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 568 | fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg, |
| 569 | eh_frame_p); |
| 570 | insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset); |
| 571 | fs->regs.cfa_offset = offset * fs->data_align; |
| 572 | fs->regs.cfa_how = CFA_REG_OFFSET; |
| 573 | break; |
| 574 | |
| 575 | case DW_CFA_def_cfa_offset_sf: |
| 576 | insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset); |
| 577 | fs->regs.cfa_offset = offset * fs->data_align; |
| 578 | /* cfa_how deliberately not set. */ |
| 579 | break; |
| 580 | |
| 581 | case DW_CFA_GNU_args_size: |
| 582 | /* Ignored. */ |
| 583 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 584 | break; |
| 585 | |
| 586 | case DW_CFA_GNU_negative_offset_extended: |
| 587 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®); |
| 588 | reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| 589 | insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp); |
| 590 | offset = utmp * fs->data_align; |
| 591 | fs->regs.alloc_regs (reg + 1); |
| 592 | fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET; |
| 593 | fs->regs.reg[reg].loc.offset = -offset; |
| 594 | break; |
| 595 | |
| 596 | default: |
| 597 | if (insn >= DW_CFA_lo_user && insn <= DW_CFA_hi_user) |
| 598 | { |
| 599 | /* Handle vendor-specific CFI for different architectures. */ |
| 600 | if (!gdbarch_execute_dwarf_cfa_vendor_op (gdbarch, insn, fs)) |
| 601 | error (_("Call Frame Instruction op %d in vendor extension " |
| 602 | "space is not handled on this architecture."), |
| 603 | insn); |
| 604 | } |
| 605 | else |
| 606 | internal_error (__FILE__, __LINE__, |
| 607 | _("Unknown CFI encountered.")); |
| 608 | } |
| 609 | } |
| 610 | } |
| 611 | |
| 612 | if (fs->initial.reg.empty ()) |
| 613 | { |
| 614 | /* Don't allow remember/restore between CIE and FDE programs. */ |
| 615 | delete fs->regs.prev; |
| 616 | fs->regs.prev = NULL; |
| 617 | } |
| 618 | |
| 619 | return insn_ptr; |
| 620 | } |
| 621 | |
| 622 | #if GDB_SELF_TEST |
| 623 | |
| 624 | namespace selftests { |
| 625 | |
| 626 | /* Unit test to function execute_cfa_program. */ |
| 627 | |
| 628 | static void |
| 629 | execute_cfa_program_test (struct gdbarch *gdbarch) |
| 630 | { |
| 631 | struct dwarf2_fde fde; |
| 632 | struct dwarf2_cie cie; |
| 633 | |
| 634 | memset (&fde, 0, sizeof fde); |
| 635 | memset (&cie, 0, sizeof cie); |
| 636 | |
| 637 | cie.data_alignment_factor = -4; |
| 638 | cie.code_alignment_factor = 2; |
| 639 | fde.cie = &cie; |
| 640 | |
| 641 | dwarf2_frame_state fs (0, fde.cie); |
| 642 | |
| 643 | gdb_byte insns[] = |
| 644 | { |
| 645 | DW_CFA_def_cfa, 1, 4, /* DW_CFA_def_cfa: r1 ofs 4 */ |
| 646 | DW_CFA_offset | 0x2, 1, /* DW_CFA_offset: r2 at cfa-4 */ |
| 647 | DW_CFA_remember_state, |
| 648 | DW_CFA_restore_state, |
| 649 | }; |
| 650 | |
| 651 | const gdb_byte *insn_end = insns + sizeof (insns); |
| 652 | const gdb_byte *out = execute_cfa_program (&fde, insns, insn_end, gdbarch, |
| 653 | 0, &fs, 0); |
| 654 | |
| 655 | SELF_CHECK (out == insn_end); |
| 656 | SELF_CHECK (fs.pc == 0); |
| 657 | |
| 658 | /* The instructions above only use r1 and r2, but the register numbers |
| 659 | used are adjusted by dwarf2_frame_adjust_regnum. */ |
| 660 | auto r1 = dwarf2_frame_adjust_regnum (gdbarch, 1, fde.eh_frame_p); |
| 661 | auto r2 = dwarf2_frame_adjust_regnum (gdbarch, 2, fde.eh_frame_p); |
| 662 | |
| 663 | SELF_CHECK (fs.regs.reg.size () == (std::max (r1, r2) + 1)); |
| 664 | |
| 665 | SELF_CHECK (fs.regs.reg[r2].how == DWARF2_FRAME_REG_SAVED_OFFSET); |
| 666 | SELF_CHECK (fs.regs.reg[r2].loc.offset == -4); |
| 667 | |
| 668 | for (auto i = 0; i < fs.regs.reg.size (); i++) |
| 669 | if (i != r2) |
| 670 | SELF_CHECK (fs.regs.reg[i].how == DWARF2_FRAME_REG_UNSPECIFIED); |
| 671 | |
| 672 | SELF_CHECK (fs.regs.cfa_reg == 1); |
| 673 | SELF_CHECK (fs.regs.cfa_offset == 4); |
| 674 | SELF_CHECK (fs.regs.cfa_how == CFA_REG_OFFSET); |
| 675 | SELF_CHECK (fs.regs.cfa_exp == NULL); |
| 676 | SELF_CHECK (fs.regs.prev == NULL); |
| 677 | } |
| 678 | |
| 679 | } // namespace selftests |
| 680 | #endif /* GDB_SELF_TEST */ |
| 681 | |
| 682 | \f |
| 683 | |
| 684 | /* Architecture-specific operations. */ |
| 685 | |
| 686 | /* Per-architecture data key. */ |
| 687 | static struct gdbarch_data *dwarf2_frame_data; |
| 688 | |
| 689 | struct dwarf2_frame_ops |
| 690 | { |
| 691 | /* Pre-initialize the register state REG for register REGNUM. */ |
| 692 | void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *, |
| 693 | struct frame_info *); |
| 694 | |
| 695 | /* Check whether the THIS_FRAME is a signal trampoline. */ |
| 696 | int (*signal_frame_p) (struct gdbarch *, struct frame_info *); |
| 697 | |
| 698 | /* Convert .eh_frame register number to DWARF register number, or |
| 699 | adjust .debug_frame register number. */ |
| 700 | int (*adjust_regnum) (struct gdbarch *, int, int); |
| 701 | }; |
| 702 | |
| 703 | /* Default architecture-specific register state initialization |
| 704 | function. */ |
| 705 | |
| 706 | static void |
| 707 | dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum, |
| 708 | struct dwarf2_frame_state_reg *reg, |
| 709 | struct frame_info *this_frame) |
| 710 | { |
| 711 | /* If we have a register that acts as a program counter, mark it as |
| 712 | a destination for the return address. If we have a register that |
| 713 | serves as the stack pointer, arrange for it to be filled with the |
| 714 | call frame address (CFA). The other registers are marked as |
| 715 | unspecified. |
| 716 | |
| 717 | We copy the return address to the program counter, since many |
| 718 | parts in GDB assume that it is possible to get the return address |
| 719 | by unwinding the program counter register. However, on ISA's |
| 720 | with a dedicated return address register, the CFI usually only |
| 721 | contains information to unwind that return address register. |
| 722 | |
| 723 | The reason we're treating the stack pointer special here is |
| 724 | because in many cases GCC doesn't emit CFI for the stack pointer |
| 725 | and implicitly assumes that it is equal to the CFA. This makes |
| 726 | some sense since the DWARF specification (version 3, draft 8, |
| 727 | p. 102) says that: |
| 728 | |
| 729 | "Typically, the CFA is defined to be the value of the stack |
| 730 | pointer at the call site in the previous frame (which may be |
| 731 | different from its value on entry to the current frame)." |
| 732 | |
| 733 | However, this isn't true for all platforms supported by GCC |
| 734 | (e.g. IBM S/390 and zSeries). Those architectures should provide |
| 735 | their own architecture-specific initialization function. */ |
| 736 | |
| 737 | if (regnum == gdbarch_pc_regnum (gdbarch)) |
| 738 | reg->how = DWARF2_FRAME_REG_RA; |
| 739 | else if (regnum == gdbarch_sp_regnum (gdbarch)) |
| 740 | reg->how = DWARF2_FRAME_REG_CFA; |
| 741 | } |
| 742 | |
| 743 | /* Return a default for the architecture-specific operations. */ |
| 744 | |
| 745 | static void * |
| 746 | dwarf2_frame_init (struct obstack *obstack) |
| 747 | { |
| 748 | struct dwarf2_frame_ops *ops; |
| 749 | |
| 750 | ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops); |
| 751 | ops->init_reg = dwarf2_frame_default_init_reg; |
| 752 | return ops; |
| 753 | } |
| 754 | |
| 755 | /* Set the architecture-specific register state initialization |
| 756 | function for GDBARCH to INIT_REG. */ |
| 757 | |
| 758 | void |
| 759 | dwarf2_frame_set_init_reg (struct gdbarch *gdbarch, |
| 760 | void (*init_reg) (struct gdbarch *, int, |
| 761 | struct dwarf2_frame_state_reg *, |
| 762 | struct frame_info *)) |
| 763 | { |
| 764 | struct dwarf2_frame_ops *ops |
| 765 | = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data); |
| 766 | |
| 767 | ops->init_reg = init_reg; |
| 768 | } |
| 769 | |
| 770 | /* Pre-initialize the register state REG for register REGNUM. */ |
| 771 | |
| 772 | static void |
| 773 | dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum, |
| 774 | struct dwarf2_frame_state_reg *reg, |
| 775 | struct frame_info *this_frame) |
| 776 | { |
| 777 | struct dwarf2_frame_ops *ops |
| 778 | = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data); |
| 779 | |
| 780 | ops->init_reg (gdbarch, regnum, reg, this_frame); |
| 781 | } |
| 782 | |
| 783 | /* Set the architecture-specific signal trampoline recognition |
| 784 | function for GDBARCH to SIGNAL_FRAME_P. */ |
| 785 | |
| 786 | void |
| 787 | dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch, |
| 788 | int (*signal_frame_p) (struct gdbarch *, |
| 789 | struct frame_info *)) |
| 790 | { |
| 791 | struct dwarf2_frame_ops *ops |
| 792 | = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data); |
| 793 | |
| 794 | ops->signal_frame_p = signal_frame_p; |
| 795 | } |
| 796 | |
| 797 | /* Query the architecture-specific signal frame recognizer for |
| 798 | THIS_FRAME. */ |
| 799 | |
| 800 | static int |
| 801 | dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch, |
| 802 | struct frame_info *this_frame) |
| 803 | { |
| 804 | struct dwarf2_frame_ops *ops |
| 805 | = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data); |
| 806 | |
| 807 | if (ops->signal_frame_p == NULL) |
| 808 | return 0; |
| 809 | return ops->signal_frame_p (gdbarch, this_frame); |
| 810 | } |
| 811 | |
| 812 | /* Set the architecture-specific adjustment of .eh_frame and .debug_frame |
| 813 | register numbers. */ |
| 814 | |
| 815 | void |
| 816 | dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch, |
| 817 | int (*adjust_regnum) (struct gdbarch *, |
| 818 | int, int)) |
| 819 | { |
| 820 | struct dwarf2_frame_ops *ops |
| 821 | = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data); |
| 822 | |
| 823 | ops->adjust_regnum = adjust_regnum; |
| 824 | } |
| 825 | |
| 826 | /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame |
| 827 | register. */ |
| 828 | |
| 829 | static int |
| 830 | dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, |
| 831 | int regnum, int eh_frame_p) |
| 832 | { |
| 833 | struct dwarf2_frame_ops *ops |
| 834 | = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data); |
| 835 | |
| 836 | if (ops->adjust_regnum == NULL) |
| 837 | return regnum; |
| 838 | return ops->adjust_regnum (gdbarch, regnum, eh_frame_p); |
| 839 | } |
| 840 | |
| 841 | static void |
| 842 | dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs, |
| 843 | struct dwarf2_fde *fde) |
| 844 | { |
| 845 | struct compunit_symtab *cust; |
| 846 | |
| 847 | cust = find_pc_compunit_symtab (fs->pc); |
| 848 | if (cust == NULL) |
| 849 | return; |
| 850 | |
| 851 | if (producer_is_realview (COMPUNIT_PRODUCER (cust))) |
| 852 | { |
| 853 | if (fde->cie->version == 1) |
| 854 | fs->armcc_cfa_offsets_sf = 1; |
| 855 | |
| 856 | if (fde->cie->version == 1) |
| 857 | fs->armcc_cfa_offsets_reversed = 1; |
| 858 | |
| 859 | /* The reversed offset problem is present in some compilers |
| 860 | using DWARF3, but it was eventually fixed. Check the ARM |
| 861 | defined augmentations, which are in the format "armcc" followed |
| 862 | by a list of one-character options. The "+" option means |
| 863 | this problem is fixed (no quirk needed). If the armcc |
| 864 | augmentation is missing, the quirk is needed. */ |
| 865 | if (fde->cie->version == 3 |
| 866 | && (!startswith (fde->cie->augmentation, "armcc") |
| 867 | || strchr (fde->cie->augmentation + 5, '+') == NULL)) |
| 868 | fs->armcc_cfa_offsets_reversed = 1; |
| 869 | |
| 870 | return; |
| 871 | } |
| 872 | } |
| 873 | \f |
| 874 | |
| 875 | /* See dwarf2-frame.h. */ |
| 876 | |
| 877 | int |
| 878 | dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc, |
| 879 | struct dwarf2_per_cu_data *data, |
| 880 | int *regnum_out, LONGEST *offset_out, |
| 881 | CORE_ADDR *text_offset_out, |
| 882 | const gdb_byte **cfa_start_out, |
| 883 | const gdb_byte **cfa_end_out) |
| 884 | { |
| 885 | struct dwarf2_fde *fde; |
| 886 | CORE_ADDR text_offset; |
| 887 | CORE_ADDR pc1 = pc; |
| 888 | |
| 889 | /* Find the correct FDE. */ |
| 890 | fde = dwarf2_frame_find_fde (&pc1, &text_offset); |
| 891 | if (fde == NULL) |
| 892 | error (_("Could not compute CFA; needed to translate this expression")); |
| 893 | |
| 894 | dwarf2_frame_state fs (pc1, fde->cie); |
| 895 | |
| 896 | /* Check for "quirks" - known bugs in producers. */ |
| 897 | dwarf2_frame_find_quirks (&fs, fde); |
| 898 | |
| 899 | /* First decode all the insns in the CIE. */ |
| 900 | execute_cfa_program (fde, fde->cie->initial_instructions, |
| 901 | fde->cie->end, gdbarch, pc, &fs, text_offset); |
| 902 | |
| 903 | /* Save the initialized register set. */ |
| 904 | fs.initial = fs.regs; |
| 905 | |
| 906 | /* Then decode the insns in the FDE up to our target PC. */ |
| 907 | execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs, |
| 908 | text_offset); |
| 909 | |
| 910 | /* Calculate the CFA. */ |
| 911 | switch (fs.regs.cfa_how) |
| 912 | { |
| 913 | case CFA_REG_OFFSET: |
| 914 | { |
| 915 | int regnum = dwarf_reg_to_regnum_or_error (gdbarch, fs.regs.cfa_reg); |
| 916 | |
| 917 | *regnum_out = regnum; |
| 918 | if (fs.armcc_cfa_offsets_reversed) |
| 919 | *offset_out = -fs.regs.cfa_offset; |
| 920 | else |
| 921 | *offset_out = fs.regs.cfa_offset; |
| 922 | return 1; |
| 923 | } |
| 924 | |
| 925 | case CFA_EXP: |
| 926 | *text_offset_out = text_offset; |
| 927 | *cfa_start_out = fs.regs.cfa_exp; |
| 928 | *cfa_end_out = fs.regs.cfa_exp + fs.regs.cfa_exp_len; |
| 929 | return 0; |
| 930 | |
| 931 | default: |
| 932 | internal_error (__FILE__, __LINE__, _("Unknown CFA rule.")); |
| 933 | } |
| 934 | } |
| 935 | |
| 936 | \f |
| 937 | struct dwarf2_frame_cache |
| 938 | { |
| 939 | /* DWARF Call Frame Address. */ |
| 940 | CORE_ADDR cfa; |
| 941 | |
| 942 | /* Set if the return address column was marked as unavailable |
| 943 | (required non-collected memory or registers to compute). */ |
| 944 | int unavailable_retaddr; |
| 945 | |
| 946 | /* Set if the return address column was marked as undefined. */ |
| 947 | int undefined_retaddr; |
| 948 | |
| 949 | /* Saved registers, indexed by GDB register number, not by DWARF |
| 950 | register number. */ |
| 951 | struct dwarf2_frame_state_reg *reg; |
| 952 | |
| 953 | /* Return address register. */ |
| 954 | struct dwarf2_frame_state_reg retaddr_reg; |
| 955 | |
| 956 | /* Target address size in bytes. */ |
| 957 | int addr_size; |
| 958 | |
| 959 | /* The .text offset. */ |
| 960 | CORE_ADDR text_offset; |
| 961 | |
| 962 | /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME |
| 963 | sequence. If NULL then it is a normal case with no TAILCALL_FRAME |
| 964 | involved. Non-bottom frames of a virtual tail call frames chain use |
| 965 | dwarf2_tailcall_frame_unwind unwinder so this field does not apply for |
| 966 | them. */ |
| 967 | void *tailcall_cache; |
| 968 | }; |
| 969 | |
| 970 | static struct dwarf2_frame_cache * |
| 971 | dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache) |
| 972 | { |
| 973 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 974 | const int num_regs = gdbarch_num_cooked_regs (gdbarch); |
| 975 | struct dwarf2_frame_cache *cache; |
| 976 | struct dwarf2_fde *fde; |
| 977 | CORE_ADDR entry_pc; |
| 978 | const gdb_byte *instr; |
| 979 | |
| 980 | if (*this_cache) |
| 981 | return (struct dwarf2_frame_cache *) *this_cache; |
| 982 | |
| 983 | /* Allocate a new cache. */ |
| 984 | cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache); |
| 985 | cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg); |
| 986 | *this_cache = cache; |
| 987 | |
| 988 | /* Unwind the PC. |
| 989 | |
| 990 | Note that if the next frame is never supposed to return (i.e. a call |
| 991 | to abort), the compiler might optimize away the instruction at |
| 992 | its return address. As a result the return address will |
| 993 | point at some random instruction, and the CFI for that |
| 994 | instruction is probably worthless to us. GCC's unwinder solves |
| 995 | this problem by substracting 1 from the return address to get an |
| 996 | address in the middle of a presumed call instruction (or the |
| 997 | instruction in the associated delay slot). This should only be |
| 998 | done for "normal" frames and not for resume-type frames (signal |
| 999 | handlers, sentinel frames, dummy frames). The function |
| 1000 | get_frame_address_in_block does just this. It's not clear how |
| 1001 | reliable the method is though; there is the potential for the |
| 1002 | register state pre-call being different to that on return. */ |
| 1003 | CORE_ADDR pc1 = get_frame_address_in_block (this_frame); |
| 1004 | |
| 1005 | /* Find the correct FDE. */ |
| 1006 | fde = dwarf2_frame_find_fde (&pc1, &cache->text_offset); |
| 1007 | gdb_assert (fde != NULL); |
| 1008 | |
| 1009 | /* Allocate and initialize the frame state. */ |
| 1010 | struct dwarf2_frame_state fs (pc1, fde->cie); |
| 1011 | |
| 1012 | cache->addr_size = fde->cie->addr_size; |
| 1013 | |
| 1014 | /* Check for "quirks" - known bugs in producers. */ |
| 1015 | dwarf2_frame_find_quirks (&fs, fde); |
| 1016 | |
| 1017 | /* First decode all the insns in the CIE. */ |
| 1018 | execute_cfa_program (fde, fde->cie->initial_instructions, |
| 1019 | fde->cie->end, gdbarch, |
| 1020 | get_frame_address_in_block (this_frame), &fs, |
| 1021 | cache->text_offset); |
| 1022 | |
| 1023 | /* Save the initialized register set. */ |
| 1024 | fs.initial = fs.regs; |
| 1025 | |
| 1026 | /* Fetching the entry pc for THIS_FRAME won't necessarily result |
| 1027 | in an address that's within the range of FDE locations. This |
| 1028 | is due to the possibility of the function occupying non-contiguous |
| 1029 | ranges. */ |
| 1030 | LONGEST entry_cfa_sp_offset; |
| 1031 | int entry_cfa_sp_offset_p = 0; |
| 1032 | if (get_frame_func_if_available (this_frame, &entry_pc) |
| 1033 | && fde->initial_location <= entry_pc |
| 1034 | && entry_pc < fde->initial_location + fde->address_range) |
| 1035 | { |
| 1036 | /* Decode the insns in the FDE up to the entry PC. */ |
| 1037 | instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, |
| 1038 | entry_pc, &fs, cache->text_offset); |
| 1039 | |
| 1040 | if (fs.regs.cfa_how == CFA_REG_OFFSET |
| 1041 | && (dwarf_reg_to_regnum (gdbarch, fs.regs.cfa_reg) |
| 1042 | == gdbarch_sp_regnum (gdbarch))) |
| 1043 | { |
| 1044 | entry_cfa_sp_offset = fs.regs.cfa_offset; |
| 1045 | entry_cfa_sp_offset_p = 1; |
| 1046 | } |
| 1047 | } |
| 1048 | else |
| 1049 | instr = fde->instructions; |
| 1050 | |
| 1051 | /* Then decode the insns in the FDE up to our target PC. */ |
| 1052 | execute_cfa_program (fde, instr, fde->end, gdbarch, |
| 1053 | get_frame_address_in_block (this_frame), &fs, |
| 1054 | cache->text_offset); |
| 1055 | |
| 1056 | try |
| 1057 | { |
| 1058 | /* Calculate the CFA. */ |
| 1059 | switch (fs.regs.cfa_how) |
| 1060 | { |
| 1061 | case CFA_REG_OFFSET: |
| 1062 | cache->cfa = read_addr_from_reg (this_frame, fs.regs.cfa_reg); |
| 1063 | if (fs.armcc_cfa_offsets_reversed) |
| 1064 | cache->cfa -= fs.regs.cfa_offset; |
| 1065 | else |
| 1066 | cache->cfa += fs.regs.cfa_offset; |
| 1067 | break; |
| 1068 | |
| 1069 | case CFA_EXP: |
| 1070 | cache->cfa = |
| 1071 | execute_stack_op (fs.regs.cfa_exp, fs.regs.cfa_exp_len, |
| 1072 | cache->addr_size, cache->text_offset, |
| 1073 | this_frame, 0, 0); |
| 1074 | break; |
| 1075 | |
| 1076 | default: |
| 1077 | internal_error (__FILE__, __LINE__, _("Unknown CFA rule.")); |
| 1078 | } |
| 1079 | } |
| 1080 | catch (const gdb_exception_error &ex) |
| 1081 | { |
| 1082 | if (ex.error == NOT_AVAILABLE_ERROR) |
| 1083 | { |
| 1084 | cache->unavailable_retaddr = 1; |
| 1085 | return cache; |
| 1086 | } |
| 1087 | |
| 1088 | throw; |
| 1089 | } |
| 1090 | |
| 1091 | /* Initialize the register state. */ |
| 1092 | { |
| 1093 | int regnum; |
| 1094 | |
| 1095 | for (regnum = 0; regnum < num_regs; regnum++) |
| 1096 | dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame); |
| 1097 | } |
| 1098 | |
| 1099 | /* Go through the DWARF2 CFI generated table and save its register |
| 1100 | location information in the cache. Note that we don't skip the |
| 1101 | return address column; it's perfectly all right for it to |
| 1102 | correspond to a real register. */ |
| 1103 | { |
| 1104 | int column; /* CFI speak for "register number". */ |
| 1105 | |
| 1106 | for (column = 0; column < fs.regs.reg.size (); column++) |
| 1107 | { |
| 1108 | /* Use the GDB register number as the destination index. */ |
| 1109 | int regnum = dwarf_reg_to_regnum (gdbarch, column); |
| 1110 | |
| 1111 | /* Protect against a target returning a bad register. */ |
| 1112 | if (regnum < 0 || regnum >= num_regs) |
| 1113 | continue; |
| 1114 | |
| 1115 | /* NOTE: cagney/2003-09-05: CFI should specify the disposition |
| 1116 | of all debug info registers. If it doesn't, complain (but |
| 1117 | not too loudly). It turns out that GCC assumes that an |
| 1118 | unspecified register implies "same value" when CFI (draft |
| 1119 | 7) specifies nothing at all. Such a register could equally |
| 1120 | be interpreted as "undefined". Also note that this check |
| 1121 | isn't sufficient; it only checks that all registers in the |
| 1122 | range [0 .. max column] are specified, and won't detect |
| 1123 | problems when a debug info register falls outside of the |
| 1124 | table. We need a way of iterating through all the valid |
| 1125 | DWARF2 register numbers. */ |
| 1126 | if (fs.regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 1127 | { |
| 1128 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| 1129 | complaint (_("\ |
| 1130 | incomplete CFI data; unspecified registers (e.g., %s) at %s"), |
| 1131 | gdbarch_register_name (gdbarch, regnum), |
| 1132 | paddress (gdbarch, fs.pc)); |
| 1133 | } |
| 1134 | else |
| 1135 | cache->reg[regnum] = fs.regs.reg[column]; |
| 1136 | } |
| 1137 | } |
| 1138 | |
| 1139 | /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information |
| 1140 | we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */ |
| 1141 | { |
| 1142 | int regnum; |
| 1143 | |
| 1144 | for (regnum = 0; regnum < num_regs; regnum++) |
| 1145 | { |
| 1146 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA |
| 1147 | || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET) |
| 1148 | { |
| 1149 | const std::vector<struct dwarf2_frame_state_reg> ®s |
| 1150 | = fs.regs.reg; |
| 1151 | ULONGEST retaddr_column = fs.retaddr_column; |
| 1152 | |
| 1153 | /* It seems rather bizarre to specify an "empty" column as |
| 1154 | the return adress column. However, this is exactly |
| 1155 | what GCC does on some targets. It turns out that GCC |
| 1156 | assumes that the return address can be found in the |
| 1157 | register corresponding to the return address column. |
| 1158 | Incidentally, that's how we should treat a return |
| 1159 | address column specifying "same value" too. */ |
| 1160 | if (fs.retaddr_column < fs.regs.reg.size () |
| 1161 | && regs[retaddr_column].how != DWARF2_FRAME_REG_UNSPECIFIED |
| 1162 | && regs[retaddr_column].how != DWARF2_FRAME_REG_SAME_VALUE) |
| 1163 | { |
| 1164 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) |
| 1165 | cache->reg[regnum] = regs[retaddr_column]; |
| 1166 | else |
| 1167 | cache->retaddr_reg = regs[retaddr_column]; |
| 1168 | } |
| 1169 | else |
| 1170 | { |
| 1171 | if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA) |
| 1172 | { |
| 1173 | cache->reg[regnum].loc.reg = fs.retaddr_column; |
| 1174 | cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG; |
| 1175 | } |
| 1176 | else |
| 1177 | { |
| 1178 | cache->retaddr_reg.loc.reg = fs.retaddr_column; |
| 1179 | cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG; |
| 1180 | } |
| 1181 | } |
| 1182 | } |
| 1183 | } |
| 1184 | } |
| 1185 | |
| 1186 | if (fs.retaddr_column < fs.regs.reg.size () |
| 1187 | && fs.regs.reg[fs.retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED) |
| 1188 | cache->undefined_retaddr = 1; |
| 1189 | |
| 1190 | dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache, |
| 1191 | (entry_cfa_sp_offset_p |
| 1192 | ? &entry_cfa_sp_offset : NULL)); |
| 1193 | |
| 1194 | return cache; |
| 1195 | } |
| 1196 | |
| 1197 | static enum unwind_stop_reason |
| 1198 | dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame, |
| 1199 | void **this_cache) |
| 1200 | { |
| 1201 | struct dwarf2_frame_cache *cache |
| 1202 | = dwarf2_frame_cache (this_frame, this_cache); |
| 1203 | |
| 1204 | if (cache->unavailable_retaddr) |
| 1205 | return UNWIND_UNAVAILABLE; |
| 1206 | |
| 1207 | if (cache->undefined_retaddr) |
| 1208 | return UNWIND_OUTERMOST; |
| 1209 | |
| 1210 | return UNWIND_NO_REASON; |
| 1211 | } |
| 1212 | |
| 1213 | static void |
| 1214 | dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache, |
| 1215 | struct frame_id *this_id) |
| 1216 | { |
| 1217 | struct dwarf2_frame_cache *cache = |
| 1218 | dwarf2_frame_cache (this_frame, this_cache); |
| 1219 | |
| 1220 | if (cache->unavailable_retaddr) |
| 1221 | (*this_id) = frame_id_build_unavailable_stack (get_frame_func (this_frame)); |
| 1222 | else if (cache->undefined_retaddr) |
| 1223 | return; |
| 1224 | else |
| 1225 | (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame)); |
| 1226 | } |
| 1227 | |
| 1228 | static struct value * |
| 1229 | dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache, |
| 1230 | int regnum) |
| 1231 | { |
| 1232 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 1233 | struct dwarf2_frame_cache *cache = |
| 1234 | dwarf2_frame_cache (this_frame, this_cache); |
| 1235 | CORE_ADDR addr; |
| 1236 | int realnum; |
| 1237 | |
| 1238 | /* Non-bottom frames of a virtual tail call frames chain use |
| 1239 | dwarf2_tailcall_frame_unwind unwinder so this code does not apply for |
| 1240 | them. If dwarf2_tailcall_prev_register_first does not have specific value |
| 1241 | unwind the register, tail call frames are assumed to have the register set |
| 1242 | of the top caller. */ |
| 1243 | if (cache->tailcall_cache) |
| 1244 | { |
| 1245 | struct value *val; |
| 1246 | |
| 1247 | val = dwarf2_tailcall_prev_register_first (this_frame, |
| 1248 | &cache->tailcall_cache, |
| 1249 | regnum); |
| 1250 | if (val) |
| 1251 | return val; |
| 1252 | } |
| 1253 | |
| 1254 | switch (cache->reg[regnum].how) |
| 1255 | { |
| 1256 | case DWARF2_FRAME_REG_UNDEFINED: |
| 1257 | /* If CFI explicitly specified that the value isn't defined, |
| 1258 | mark it as optimized away; the value isn't available. */ |
| 1259 | return frame_unwind_got_optimized (this_frame, regnum); |
| 1260 | |
| 1261 | case DWARF2_FRAME_REG_SAVED_OFFSET: |
| 1262 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1263 | return frame_unwind_got_memory (this_frame, regnum, addr); |
| 1264 | |
| 1265 | case DWARF2_FRAME_REG_SAVED_REG: |
| 1266 | realnum = dwarf_reg_to_regnum_or_error |
| 1267 | (gdbarch, cache->reg[regnum].loc.reg); |
| 1268 | return frame_unwind_got_register (this_frame, regnum, realnum); |
| 1269 | |
| 1270 | case DWARF2_FRAME_REG_SAVED_EXP: |
| 1271 | addr = execute_stack_op (cache->reg[regnum].loc.exp.start, |
| 1272 | cache->reg[regnum].loc.exp.len, |
| 1273 | cache->addr_size, cache->text_offset, |
| 1274 | this_frame, cache->cfa, 1); |
| 1275 | return frame_unwind_got_memory (this_frame, regnum, addr); |
| 1276 | |
| 1277 | case DWARF2_FRAME_REG_SAVED_VAL_OFFSET: |
| 1278 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1279 | return frame_unwind_got_constant (this_frame, regnum, addr); |
| 1280 | |
| 1281 | case DWARF2_FRAME_REG_SAVED_VAL_EXP: |
| 1282 | addr = execute_stack_op (cache->reg[regnum].loc.exp.start, |
| 1283 | cache->reg[regnum].loc.exp.len, |
| 1284 | cache->addr_size, cache->text_offset, |
| 1285 | this_frame, cache->cfa, 1); |
| 1286 | return frame_unwind_got_constant (this_frame, regnum, addr); |
| 1287 | |
| 1288 | case DWARF2_FRAME_REG_UNSPECIFIED: |
| 1289 | /* GCC, in its infinite wisdom decided to not provide unwind |
| 1290 | information for registers that are "same value". Since |
| 1291 | DWARF2 (3 draft 7) doesn't define such behavior, said |
| 1292 | registers are actually undefined (which is different to CFI |
| 1293 | "undefined"). Code above issues a complaint about this. |
| 1294 | Here just fudge the books, assume GCC, and that the value is |
| 1295 | more inner on the stack. */ |
| 1296 | return frame_unwind_got_register (this_frame, regnum, regnum); |
| 1297 | |
| 1298 | case DWARF2_FRAME_REG_SAME_VALUE: |
| 1299 | return frame_unwind_got_register (this_frame, regnum, regnum); |
| 1300 | |
| 1301 | case DWARF2_FRAME_REG_CFA: |
| 1302 | return frame_unwind_got_address (this_frame, regnum, cache->cfa); |
| 1303 | |
| 1304 | case DWARF2_FRAME_REG_CFA_OFFSET: |
| 1305 | addr = cache->cfa + cache->reg[regnum].loc.offset; |
| 1306 | return frame_unwind_got_address (this_frame, regnum, addr); |
| 1307 | |
| 1308 | case DWARF2_FRAME_REG_RA_OFFSET: |
| 1309 | addr = cache->reg[regnum].loc.offset; |
| 1310 | regnum = dwarf_reg_to_regnum_or_error |
| 1311 | (gdbarch, cache->retaddr_reg.loc.reg); |
| 1312 | addr += get_frame_register_unsigned (this_frame, regnum); |
| 1313 | return frame_unwind_got_address (this_frame, regnum, addr); |
| 1314 | |
| 1315 | case DWARF2_FRAME_REG_FN: |
| 1316 | return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum); |
| 1317 | |
| 1318 | default: |
| 1319 | internal_error (__FILE__, __LINE__, _("Unknown register rule.")); |
| 1320 | } |
| 1321 | } |
| 1322 | |
| 1323 | /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail |
| 1324 | call frames chain. */ |
| 1325 | |
| 1326 | static void |
| 1327 | dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache) |
| 1328 | { |
| 1329 | struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache); |
| 1330 | |
| 1331 | if (cache->tailcall_cache) |
| 1332 | dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache); |
| 1333 | } |
| 1334 | |
| 1335 | static int |
| 1336 | dwarf2_frame_sniffer (const struct frame_unwind *self, |
| 1337 | struct frame_info *this_frame, void **this_cache) |
| 1338 | { |
| 1339 | if (!dwarf2_frame_unwinders_enabled_p) |
| 1340 | return 0; |
| 1341 | |
| 1342 | /* Grab an address that is guaranteed to reside somewhere within the |
| 1343 | function. get_frame_pc(), with a no-return next function, can |
| 1344 | end up returning something past the end of this function's body. |
| 1345 | If the frame we're sniffing for is a signal frame whose start |
| 1346 | address is placed on the stack by the OS, its FDE must |
| 1347 | extend one byte before its start address or we could potentially |
| 1348 | select the FDE of the previous function. */ |
| 1349 | CORE_ADDR block_addr = get_frame_address_in_block (this_frame); |
| 1350 | struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL); |
| 1351 | |
| 1352 | if (!fde) |
| 1353 | return 0; |
| 1354 | |
| 1355 | /* On some targets, signal trampolines may have unwind information. |
| 1356 | We need to recognize them so that we set the frame type |
| 1357 | correctly. */ |
| 1358 | |
| 1359 | if (fde->cie->signal_frame |
| 1360 | || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame), |
| 1361 | this_frame)) |
| 1362 | return self->type == SIGTRAMP_FRAME; |
| 1363 | |
| 1364 | if (self->type != NORMAL_FRAME) |
| 1365 | return 0; |
| 1366 | |
| 1367 | return 1; |
| 1368 | } |
| 1369 | |
| 1370 | static const struct frame_unwind dwarf2_frame_unwind = |
| 1371 | { |
| 1372 | NORMAL_FRAME, |
| 1373 | dwarf2_frame_unwind_stop_reason, |
| 1374 | dwarf2_frame_this_id, |
| 1375 | dwarf2_frame_prev_register, |
| 1376 | NULL, |
| 1377 | dwarf2_frame_sniffer, |
| 1378 | dwarf2_frame_dealloc_cache |
| 1379 | }; |
| 1380 | |
| 1381 | static const struct frame_unwind dwarf2_signal_frame_unwind = |
| 1382 | { |
| 1383 | SIGTRAMP_FRAME, |
| 1384 | dwarf2_frame_unwind_stop_reason, |
| 1385 | dwarf2_frame_this_id, |
| 1386 | dwarf2_frame_prev_register, |
| 1387 | NULL, |
| 1388 | dwarf2_frame_sniffer, |
| 1389 | |
| 1390 | /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */ |
| 1391 | NULL |
| 1392 | }; |
| 1393 | |
| 1394 | /* Append the DWARF-2 frame unwinders to GDBARCH's list. */ |
| 1395 | |
| 1396 | void |
| 1397 | dwarf2_append_unwinders (struct gdbarch *gdbarch) |
| 1398 | { |
| 1399 | frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind); |
| 1400 | frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind); |
| 1401 | } |
| 1402 | \f |
| 1403 | |
| 1404 | /* There is no explicitly defined relationship between the CFA and the |
| 1405 | location of frame's local variables and arguments/parameters. |
| 1406 | Therefore, frame base methods on this page should probably only be |
| 1407 | used as a last resort, just to avoid printing total garbage as a |
| 1408 | response to the "info frame" command. */ |
| 1409 | |
| 1410 | static CORE_ADDR |
| 1411 | dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache) |
| 1412 | { |
| 1413 | struct dwarf2_frame_cache *cache = |
| 1414 | dwarf2_frame_cache (this_frame, this_cache); |
| 1415 | |
| 1416 | return cache->cfa; |
| 1417 | } |
| 1418 | |
| 1419 | static const struct frame_base dwarf2_frame_base = |
| 1420 | { |
| 1421 | &dwarf2_frame_unwind, |
| 1422 | dwarf2_frame_base_address, |
| 1423 | dwarf2_frame_base_address, |
| 1424 | dwarf2_frame_base_address |
| 1425 | }; |
| 1426 | |
| 1427 | const struct frame_base * |
| 1428 | dwarf2_frame_base_sniffer (struct frame_info *this_frame) |
| 1429 | { |
| 1430 | CORE_ADDR block_addr = get_frame_address_in_block (this_frame); |
| 1431 | |
| 1432 | if (dwarf2_frame_find_fde (&block_addr, NULL)) |
| 1433 | return &dwarf2_frame_base; |
| 1434 | |
| 1435 | return NULL; |
| 1436 | } |
| 1437 | |
| 1438 | /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from |
| 1439 | the DWARF unwinder. This is used to implement |
| 1440 | DW_OP_call_frame_cfa. */ |
| 1441 | |
| 1442 | CORE_ADDR |
| 1443 | dwarf2_frame_cfa (struct frame_info *this_frame) |
| 1444 | { |
| 1445 | if (frame_unwinder_is (this_frame, &record_btrace_tailcall_frame_unwind) |
| 1446 | || frame_unwinder_is (this_frame, &record_btrace_frame_unwind)) |
| 1447 | throw_error (NOT_AVAILABLE_ERROR, |
| 1448 | _("cfa not available for record btrace target")); |
| 1449 | |
| 1450 | while (get_frame_type (this_frame) == INLINE_FRAME) |
| 1451 | this_frame = get_prev_frame (this_frame); |
| 1452 | if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE) |
| 1453 | throw_error (NOT_AVAILABLE_ERROR, |
| 1454 | _("can't compute CFA for this frame: " |
| 1455 | "required registers or memory are unavailable")); |
| 1456 | |
| 1457 | if (get_frame_id (this_frame).stack_status != FID_STACK_VALID) |
| 1458 | throw_error (NOT_AVAILABLE_ERROR, |
| 1459 | _("can't compute CFA for this frame: " |
| 1460 | "frame base not available")); |
| 1461 | |
| 1462 | return get_frame_base (this_frame); |
| 1463 | } |
| 1464 | \f |
| 1465 | /* We store the frame data on the BFD. This is only done if it is |
| 1466 | independent of the address space and so can be shared. */ |
| 1467 | static const struct bfd_key<comp_unit> dwarf2_frame_bfd_data; |
| 1468 | |
| 1469 | /* If any BFD sections require relocations (note; really should be if |
| 1470 | any debug info requires relocations), then we store the frame data |
| 1471 | on the objfile instead, and do not share it. */ |
| 1472 | const struct objfile_key<comp_unit> dwarf2_frame_objfile_data; |
| 1473 | \f |
| 1474 | |
| 1475 | /* Pointer encoding helper functions. */ |
| 1476 | |
| 1477 | /* GCC supports exception handling based on DWARF2 CFI. However, for |
| 1478 | technical reasons, it encodes addresses in its FDE's in a different |
| 1479 | way. Several "pointer encodings" are supported. The encoding |
| 1480 | that's used for a particular FDE is determined by the 'R' |
| 1481 | augmentation in the associated CIE. The argument of this |
| 1482 | augmentation is a single byte. |
| 1483 | |
| 1484 | The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a |
| 1485 | LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether |
| 1486 | the address is signed or unsigned. Bits 4, 5 and 6 encode how the |
| 1487 | address should be interpreted (absolute, relative to the current |
| 1488 | position in the FDE, ...). Bit 7, indicates that the address |
| 1489 | should be dereferenced. */ |
| 1490 | |
| 1491 | static gdb_byte |
| 1492 | encoding_for_size (unsigned int size) |
| 1493 | { |
| 1494 | switch (size) |
| 1495 | { |
| 1496 | case 2: |
| 1497 | return DW_EH_PE_udata2; |
| 1498 | case 4: |
| 1499 | return DW_EH_PE_udata4; |
| 1500 | case 8: |
| 1501 | return DW_EH_PE_udata8; |
| 1502 | default: |
| 1503 | internal_error (__FILE__, __LINE__, _("Unsupported address size")); |
| 1504 | } |
| 1505 | } |
| 1506 | |
| 1507 | static CORE_ADDR |
| 1508 | read_encoded_value (struct comp_unit *unit, gdb_byte encoding, |
| 1509 | int ptr_len, const gdb_byte *buf, |
| 1510 | unsigned int *bytes_read_ptr, |
| 1511 | CORE_ADDR func_base) |
| 1512 | { |
| 1513 | ptrdiff_t offset; |
| 1514 | CORE_ADDR base; |
| 1515 | |
| 1516 | /* GCC currently doesn't generate DW_EH_PE_indirect encodings for |
| 1517 | FDE's. */ |
| 1518 | if (encoding & DW_EH_PE_indirect) |
| 1519 | internal_error (__FILE__, __LINE__, |
| 1520 | _("Unsupported encoding: DW_EH_PE_indirect")); |
| 1521 | |
| 1522 | *bytes_read_ptr = 0; |
| 1523 | |
| 1524 | switch (encoding & 0x70) |
| 1525 | { |
| 1526 | case DW_EH_PE_absptr: |
| 1527 | base = 0; |
| 1528 | break; |
| 1529 | case DW_EH_PE_pcrel: |
| 1530 | base = bfd_section_vma (unit->dwarf_frame_section); |
| 1531 | base += (buf - unit->dwarf_frame_buffer); |
| 1532 | break; |
| 1533 | case DW_EH_PE_datarel: |
| 1534 | base = unit->dbase; |
| 1535 | break; |
| 1536 | case DW_EH_PE_textrel: |
| 1537 | base = unit->tbase; |
| 1538 | break; |
| 1539 | case DW_EH_PE_funcrel: |
| 1540 | base = func_base; |
| 1541 | break; |
| 1542 | case DW_EH_PE_aligned: |
| 1543 | base = 0; |
| 1544 | offset = buf - unit->dwarf_frame_buffer; |
| 1545 | if ((offset % ptr_len) != 0) |
| 1546 | { |
| 1547 | *bytes_read_ptr = ptr_len - (offset % ptr_len); |
| 1548 | buf += *bytes_read_ptr; |
| 1549 | } |
| 1550 | break; |
| 1551 | default: |
| 1552 | internal_error (__FILE__, __LINE__, |
| 1553 | _("Invalid or unsupported encoding")); |
| 1554 | } |
| 1555 | |
| 1556 | if ((encoding & 0x07) == 0x00) |
| 1557 | { |
| 1558 | encoding |= encoding_for_size (ptr_len); |
| 1559 | if (bfd_get_sign_extend_vma (unit->abfd)) |
| 1560 | encoding |= DW_EH_PE_signed; |
| 1561 | } |
| 1562 | |
| 1563 | switch (encoding & 0x0f) |
| 1564 | { |
| 1565 | case DW_EH_PE_uleb128: |
| 1566 | { |
| 1567 | uint64_t value; |
| 1568 | const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
| 1569 | |
| 1570 | *bytes_read_ptr += safe_read_uleb128 (buf, end_buf, &value) - buf; |
| 1571 | return base + value; |
| 1572 | } |
| 1573 | case DW_EH_PE_udata2: |
| 1574 | *bytes_read_ptr += 2; |
| 1575 | return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf)); |
| 1576 | case DW_EH_PE_udata4: |
| 1577 | *bytes_read_ptr += 4; |
| 1578 | return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf)); |
| 1579 | case DW_EH_PE_udata8: |
| 1580 | *bytes_read_ptr += 8; |
| 1581 | return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf)); |
| 1582 | case DW_EH_PE_sleb128: |
| 1583 | { |
| 1584 | int64_t value; |
| 1585 | const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7; |
| 1586 | |
| 1587 | *bytes_read_ptr += safe_read_sleb128 (buf, end_buf, &value) - buf; |
| 1588 | return base + value; |
| 1589 | } |
| 1590 | case DW_EH_PE_sdata2: |
| 1591 | *bytes_read_ptr += 2; |
| 1592 | return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf)); |
| 1593 | case DW_EH_PE_sdata4: |
| 1594 | *bytes_read_ptr += 4; |
| 1595 | return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf)); |
| 1596 | case DW_EH_PE_sdata8: |
| 1597 | *bytes_read_ptr += 8; |
| 1598 | return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf)); |
| 1599 | default: |
| 1600 | internal_error (__FILE__, __LINE__, |
| 1601 | _("Invalid or unsupported encoding")); |
| 1602 | } |
| 1603 | } |
| 1604 | \f |
| 1605 | |
| 1606 | /* Find CIE with the given CIE_POINTER in CIE_TABLE. */ |
| 1607 | static struct dwarf2_cie * |
| 1608 | find_cie (const dwarf2_cie_table &cie_table, ULONGEST cie_pointer) |
| 1609 | { |
| 1610 | auto iter = cie_table.find (cie_pointer); |
| 1611 | if (iter != cie_table.end ()) |
| 1612 | return iter->second; |
| 1613 | return NULL; |
| 1614 | } |
| 1615 | |
| 1616 | static inline int |
| 1617 | bsearch_fde_cmp (const dwarf2_fde *fde, CORE_ADDR seek_pc) |
| 1618 | { |
| 1619 | if (fde->initial_location + fde->address_range <= seek_pc) |
| 1620 | return -1; |
| 1621 | if (fde->initial_location <= seek_pc) |
| 1622 | return 0; |
| 1623 | return 1; |
| 1624 | } |
| 1625 | |
| 1626 | /* Find an existing comp_unit for an objfile, if any. */ |
| 1627 | |
| 1628 | static comp_unit * |
| 1629 | find_comp_unit (struct objfile *objfile) |
| 1630 | { |
| 1631 | bfd *abfd = objfile->obfd; |
| 1632 | if (gdb_bfd_requires_relocations (abfd)) |
| 1633 | return dwarf2_frame_bfd_data.get (abfd); |
| 1634 | return dwarf2_frame_objfile_data.get (objfile); |
| 1635 | } |
| 1636 | |
| 1637 | /* Store the comp_unit on OBJFILE, or the corresponding BFD, as |
| 1638 | appropriate. */ |
| 1639 | |
| 1640 | static void |
| 1641 | set_comp_unit (struct objfile *objfile, struct comp_unit *unit) |
| 1642 | { |
| 1643 | bfd *abfd = objfile->obfd; |
| 1644 | if (gdb_bfd_requires_relocations (abfd)) |
| 1645 | return dwarf2_frame_bfd_data.set (abfd, unit); |
| 1646 | return dwarf2_frame_objfile_data.set (objfile, unit); |
| 1647 | } |
| 1648 | |
| 1649 | /* Find the FDE for *PC. Return a pointer to the FDE, and store the |
| 1650 | initial location associated with it into *PC. */ |
| 1651 | |
| 1652 | static struct dwarf2_fde * |
| 1653 | dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset) |
| 1654 | { |
| 1655 | for (objfile *objfile : current_program_space->objfiles ()) |
| 1656 | { |
| 1657 | CORE_ADDR offset; |
| 1658 | CORE_ADDR seek_pc; |
| 1659 | |
| 1660 | comp_unit *unit = find_comp_unit (objfile); |
| 1661 | if (unit == NULL) |
| 1662 | { |
| 1663 | dwarf2_build_frame_info (objfile); |
| 1664 | unit = find_comp_unit (objfile); |
| 1665 | } |
| 1666 | gdb_assert (unit != NULL); |
| 1667 | |
| 1668 | dwarf2_fde_table *fde_table = &unit->fde_table; |
| 1669 | if (fde_table->empty ()) |
| 1670 | continue; |
| 1671 | |
| 1672 | gdb_assert (!objfile->section_offsets.empty ()); |
| 1673 | offset = objfile->text_section_offset (); |
| 1674 | |
| 1675 | gdb_assert (!fde_table->empty ()); |
| 1676 | if (*pc < offset + (*fde_table)[0]->initial_location) |
| 1677 | continue; |
| 1678 | |
| 1679 | seek_pc = *pc - offset; |
| 1680 | auto it = gdb::binary_search (fde_table->begin (), fde_table->end (), |
| 1681 | seek_pc, bsearch_fde_cmp); |
| 1682 | if (it != fde_table->end ()) |
| 1683 | { |
| 1684 | *pc = (*it)->initial_location + offset; |
| 1685 | if (out_offset) |
| 1686 | *out_offset = offset; |
| 1687 | return *it; |
| 1688 | } |
| 1689 | } |
| 1690 | return NULL; |
| 1691 | } |
| 1692 | |
| 1693 | /* Add FDE to FDE_TABLE. */ |
| 1694 | static void |
| 1695 | add_fde (dwarf2_fde_table *fde_table, struct dwarf2_fde *fde) |
| 1696 | { |
| 1697 | if (fde->address_range == 0) |
| 1698 | /* Discard useless FDEs. */ |
| 1699 | return; |
| 1700 | |
| 1701 | fde_table->push_back (fde); |
| 1702 | } |
| 1703 | |
| 1704 | #define DW64_CIE_ID 0xffffffffffffffffULL |
| 1705 | |
| 1706 | /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE |
| 1707 | or any of them. */ |
| 1708 | |
| 1709 | enum eh_frame_type |
| 1710 | { |
| 1711 | EH_CIE_TYPE_ID = 1 << 0, |
| 1712 | EH_FDE_TYPE_ID = 1 << 1, |
| 1713 | EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID |
| 1714 | }; |
| 1715 | |
| 1716 | static const gdb_byte *decode_frame_entry (struct gdbarch *gdbarch, |
| 1717 | struct comp_unit *unit, |
| 1718 | const gdb_byte *start, |
| 1719 | int eh_frame_p, |
| 1720 | dwarf2_cie_table &cie_table, |
| 1721 | dwarf2_fde_table *fde_table, |
| 1722 | enum eh_frame_type entry_type); |
| 1723 | |
| 1724 | /* Decode the next CIE or FDE, entry_type specifies the expected type. |
| 1725 | Return NULL if invalid input, otherwise the next byte to be processed. */ |
| 1726 | |
| 1727 | static const gdb_byte * |
| 1728 | decode_frame_entry_1 (struct gdbarch *gdbarch, |
| 1729 | struct comp_unit *unit, const gdb_byte *start, |
| 1730 | int eh_frame_p, |
| 1731 | dwarf2_cie_table &cie_table, |
| 1732 | dwarf2_fde_table *fde_table, |
| 1733 | enum eh_frame_type entry_type) |
| 1734 | { |
| 1735 | const gdb_byte *buf, *end; |
| 1736 | ULONGEST length; |
| 1737 | unsigned int bytes_read; |
| 1738 | int dwarf64_p; |
| 1739 | ULONGEST cie_id; |
| 1740 | ULONGEST cie_pointer; |
| 1741 | int64_t sleb128; |
| 1742 | uint64_t uleb128; |
| 1743 | |
| 1744 | buf = start; |
| 1745 | length = read_initial_length (unit->abfd, buf, &bytes_read, false); |
| 1746 | buf += bytes_read; |
| 1747 | end = buf + (size_t) length; |
| 1748 | |
| 1749 | if (length == 0) |
| 1750 | return end; |
| 1751 | |
| 1752 | /* Are we still within the section? */ |
| 1753 | if (end <= buf || end > unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 1754 | return NULL; |
| 1755 | |
| 1756 | /* Distinguish between 32 and 64-bit encoded frame info. */ |
| 1757 | dwarf64_p = (bytes_read == 12); |
| 1758 | |
| 1759 | /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */ |
| 1760 | if (eh_frame_p) |
| 1761 | cie_id = 0; |
| 1762 | else if (dwarf64_p) |
| 1763 | cie_id = DW64_CIE_ID; |
| 1764 | else |
| 1765 | cie_id = DW_CIE_ID; |
| 1766 | |
| 1767 | if (dwarf64_p) |
| 1768 | { |
| 1769 | cie_pointer = read_8_bytes (unit->abfd, buf); |
| 1770 | buf += 8; |
| 1771 | } |
| 1772 | else |
| 1773 | { |
| 1774 | cie_pointer = read_4_bytes (unit->abfd, buf); |
| 1775 | buf += 4; |
| 1776 | } |
| 1777 | |
| 1778 | if (cie_pointer == cie_id) |
| 1779 | { |
| 1780 | /* This is a CIE. */ |
| 1781 | struct dwarf2_cie *cie; |
| 1782 | char *augmentation; |
| 1783 | unsigned int cie_version; |
| 1784 | |
| 1785 | /* Check that a CIE was expected. */ |
| 1786 | if ((entry_type & EH_CIE_TYPE_ID) == 0) |
| 1787 | error (_("Found a CIE when not expecting it.")); |
| 1788 | |
| 1789 | /* Record the offset into the .debug_frame section of this CIE. */ |
| 1790 | cie_pointer = start - unit->dwarf_frame_buffer; |
| 1791 | |
| 1792 | /* Check whether we've already read it. */ |
| 1793 | if (find_cie (cie_table, cie_pointer)) |
| 1794 | return end; |
| 1795 | |
| 1796 | cie = XOBNEW (&unit->obstack, struct dwarf2_cie); |
| 1797 | cie->initial_instructions = NULL; |
| 1798 | cie->cie_pointer = cie_pointer; |
| 1799 | |
| 1800 | /* The encoding for FDE's in a normal .debug_frame section |
| 1801 | depends on the target address size. */ |
| 1802 | cie->encoding = DW_EH_PE_absptr; |
| 1803 | |
| 1804 | /* We'll determine the final value later, but we need to |
| 1805 | initialize it conservatively. */ |
| 1806 | cie->signal_frame = 0; |
| 1807 | |
| 1808 | /* Check version number. */ |
| 1809 | cie_version = read_1_byte (unit->abfd, buf); |
| 1810 | if (cie_version != 1 && cie_version != 3 && cie_version != 4) |
| 1811 | return NULL; |
| 1812 | cie->version = cie_version; |
| 1813 | buf += 1; |
| 1814 | |
| 1815 | /* Interpret the interesting bits of the augmentation. */ |
| 1816 | cie->augmentation = augmentation = (char *) buf; |
| 1817 | buf += (strlen (augmentation) + 1); |
| 1818 | |
| 1819 | /* Ignore armcc augmentations. We only use them for quirks, |
| 1820 | and that doesn't happen until later. */ |
| 1821 | if (startswith (augmentation, "armcc")) |
| 1822 | augmentation += strlen (augmentation); |
| 1823 | |
| 1824 | /* The GCC 2.x "eh" augmentation has a pointer immediately |
| 1825 | following the augmentation string, so it must be handled |
| 1826 | first. */ |
| 1827 | if (augmentation[0] == 'e' && augmentation[1] == 'h') |
| 1828 | { |
| 1829 | /* Skip. */ |
| 1830 | buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT; |
| 1831 | augmentation += 2; |
| 1832 | } |
| 1833 | |
| 1834 | if (cie->version >= 4) |
| 1835 | { |
| 1836 | /* FIXME: check that this is the same as from the CU header. */ |
| 1837 | cie->addr_size = read_1_byte (unit->abfd, buf); |
| 1838 | ++buf; |
| 1839 | cie->segment_size = read_1_byte (unit->abfd, buf); |
| 1840 | ++buf; |
| 1841 | } |
| 1842 | else |
| 1843 | { |
| 1844 | cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch); |
| 1845 | cie->segment_size = 0; |
| 1846 | } |
| 1847 | /* Address values in .eh_frame sections are defined to have the |
| 1848 | target's pointer size. Watchout: This breaks frame info for |
| 1849 | targets with pointer size < address size, unless a .debug_frame |
| 1850 | section exists as well. */ |
| 1851 | if (eh_frame_p) |
| 1852 | cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT; |
| 1853 | else |
| 1854 | cie->ptr_size = cie->addr_size; |
| 1855 | |
| 1856 | buf = gdb_read_uleb128 (buf, end, &uleb128); |
| 1857 | if (buf == NULL) |
| 1858 | return NULL; |
| 1859 | cie->code_alignment_factor = uleb128; |
| 1860 | |
| 1861 | buf = gdb_read_sleb128 (buf, end, &sleb128); |
| 1862 | if (buf == NULL) |
| 1863 | return NULL; |
| 1864 | cie->data_alignment_factor = sleb128; |
| 1865 | |
| 1866 | if (cie_version == 1) |
| 1867 | { |
| 1868 | cie->return_address_register = read_1_byte (unit->abfd, buf); |
| 1869 | ++buf; |
| 1870 | } |
| 1871 | else |
| 1872 | { |
| 1873 | buf = gdb_read_uleb128 (buf, end, &uleb128); |
| 1874 | if (buf == NULL) |
| 1875 | return NULL; |
| 1876 | cie->return_address_register = uleb128; |
| 1877 | } |
| 1878 | |
| 1879 | cie->return_address_register |
| 1880 | = dwarf2_frame_adjust_regnum (gdbarch, |
| 1881 | cie->return_address_register, |
| 1882 | eh_frame_p); |
| 1883 | |
| 1884 | cie->saw_z_augmentation = (*augmentation == 'z'); |
| 1885 | if (cie->saw_z_augmentation) |
| 1886 | { |
| 1887 | uint64_t uleb_length; |
| 1888 | |
| 1889 | buf = gdb_read_uleb128 (buf, end, &uleb_length); |
| 1890 | if (buf == NULL) |
| 1891 | return NULL; |
| 1892 | cie->initial_instructions = buf + uleb_length; |
| 1893 | augmentation++; |
| 1894 | } |
| 1895 | |
| 1896 | while (*augmentation) |
| 1897 | { |
| 1898 | /* "L" indicates a byte showing how the LSDA pointer is encoded. */ |
| 1899 | if (*augmentation == 'L') |
| 1900 | { |
| 1901 | /* Skip. */ |
| 1902 | buf++; |
| 1903 | augmentation++; |
| 1904 | } |
| 1905 | |
| 1906 | /* "R" indicates a byte indicating how FDE addresses are encoded. */ |
| 1907 | else if (*augmentation == 'R') |
| 1908 | { |
| 1909 | cie->encoding = *buf++; |
| 1910 | augmentation++; |
| 1911 | } |
| 1912 | |
| 1913 | /* "P" indicates a personality routine in the CIE augmentation. */ |
| 1914 | else if (*augmentation == 'P') |
| 1915 | { |
| 1916 | /* Skip. Avoid indirection since we throw away the result. */ |
| 1917 | gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect; |
| 1918 | read_encoded_value (unit, encoding, cie->ptr_size, |
| 1919 | buf, &bytes_read, 0); |
| 1920 | buf += bytes_read; |
| 1921 | augmentation++; |
| 1922 | } |
| 1923 | |
| 1924 | /* "S" indicates a signal frame, such that the return |
| 1925 | address must not be decremented to locate the call frame |
| 1926 | info for the previous frame; it might even be the first |
| 1927 | instruction of a function, so decrementing it would take |
| 1928 | us to a different function. */ |
| 1929 | else if (*augmentation == 'S') |
| 1930 | { |
| 1931 | cie->signal_frame = 1; |
| 1932 | augmentation++; |
| 1933 | } |
| 1934 | |
| 1935 | /* Otherwise we have an unknown augmentation. Assume that either |
| 1936 | there is no augmentation data, or we saw a 'z' prefix. */ |
| 1937 | else |
| 1938 | { |
| 1939 | if (cie->initial_instructions) |
| 1940 | buf = cie->initial_instructions; |
| 1941 | break; |
| 1942 | } |
| 1943 | } |
| 1944 | |
| 1945 | cie->initial_instructions = buf; |
| 1946 | cie->end = end; |
| 1947 | cie->unit = unit; |
| 1948 | |
| 1949 | cie_table[cie->cie_pointer] = cie; |
| 1950 | } |
| 1951 | else |
| 1952 | { |
| 1953 | /* This is a FDE. */ |
| 1954 | struct dwarf2_fde *fde; |
| 1955 | CORE_ADDR addr; |
| 1956 | |
| 1957 | /* Check that an FDE was expected. */ |
| 1958 | if ((entry_type & EH_FDE_TYPE_ID) == 0) |
| 1959 | error (_("Found an FDE when not expecting it.")); |
| 1960 | |
| 1961 | /* In an .eh_frame section, the CIE pointer is the delta between the |
| 1962 | address within the FDE where the CIE pointer is stored and the |
| 1963 | address of the CIE. Convert it to an offset into the .eh_frame |
| 1964 | section. */ |
| 1965 | if (eh_frame_p) |
| 1966 | { |
| 1967 | cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer; |
| 1968 | cie_pointer -= (dwarf64_p ? 8 : 4); |
| 1969 | } |
| 1970 | |
| 1971 | /* In either case, validate the result is still within the section. */ |
| 1972 | if (cie_pointer >= unit->dwarf_frame_size) |
| 1973 | return NULL; |
| 1974 | |
| 1975 | fde = XOBNEW (&unit->obstack, struct dwarf2_fde); |
| 1976 | fde->cie = find_cie (cie_table, cie_pointer); |
| 1977 | if (fde->cie == NULL) |
| 1978 | { |
| 1979 | decode_frame_entry (gdbarch, unit, |
| 1980 | unit->dwarf_frame_buffer + cie_pointer, |
| 1981 | eh_frame_p, cie_table, fde_table, |
| 1982 | EH_CIE_TYPE_ID); |
| 1983 | fde->cie = find_cie (cie_table, cie_pointer); |
| 1984 | } |
| 1985 | |
| 1986 | gdb_assert (fde->cie != NULL); |
| 1987 | |
| 1988 | addr = read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size, |
| 1989 | buf, &bytes_read, 0); |
| 1990 | fde->initial_location = gdbarch_adjust_dwarf2_addr (gdbarch, addr); |
| 1991 | buf += bytes_read; |
| 1992 | |
| 1993 | fde->address_range = |
| 1994 | read_encoded_value (unit, fde->cie->encoding & 0x0f, |
| 1995 | fde->cie->ptr_size, buf, &bytes_read, 0); |
| 1996 | addr = gdbarch_adjust_dwarf2_addr (gdbarch, addr + fde->address_range); |
| 1997 | fde->address_range = addr - fde->initial_location; |
| 1998 | buf += bytes_read; |
| 1999 | |
| 2000 | /* A 'z' augmentation in the CIE implies the presence of an |
| 2001 | augmentation field in the FDE as well. The only thing known |
| 2002 | to be in here at present is the LSDA entry for EH. So we |
| 2003 | can skip the whole thing. */ |
| 2004 | if (fde->cie->saw_z_augmentation) |
| 2005 | { |
| 2006 | uint64_t uleb_length; |
| 2007 | |
| 2008 | buf = gdb_read_uleb128 (buf, end, &uleb_length); |
| 2009 | if (buf == NULL) |
| 2010 | return NULL; |
| 2011 | buf += uleb_length; |
| 2012 | if (buf > end) |
| 2013 | return NULL; |
| 2014 | } |
| 2015 | |
| 2016 | fde->instructions = buf; |
| 2017 | fde->end = end; |
| 2018 | |
| 2019 | fde->eh_frame_p = eh_frame_p; |
| 2020 | |
| 2021 | add_fde (fde_table, fde); |
| 2022 | } |
| 2023 | |
| 2024 | return end; |
| 2025 | } |
| 2026 | |
| 2027 | /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we |
| 2028 | expect an FDE or a CIE. */ |
| 2029 | |
| 2030 | static const gdb_byte * |
| 2031 | decode_frame_entry (struct gdbarch *gdbarch, |
| 2032 | struct comp_unit *unit, const gdb_byte *start, |
| 2033 | int eh_frame_p, |
| 2034 | dwarf2_cie_table &cie_table, |
| 2035 | dwarf2_fde_table *fde_table, |
| 2036 | enum eh_frame_type entry_type) |
| 2037 | { |
| 2038 | enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE; |
| 2039 | const gdb_byte *ret; |
| 2040 | ptrdiff_t start_offset; |
| 2041 | |
| 2042 | while (1) |
| 2043 | { |
| 2044 | ret = decode_frame_entry_1 (gdbarch, unit, start, eh_frame_p, |
| 2045 | cie_table, fde_table, entry_type); |
| 2046 | if (ret != NULL) |
| 2047 | break; |
| 2048 | |
| 2049 | /* We have corrupt input data of some form. */ |
| 2050 | |
| 2051 | /* ??? Try, weakly, to work around compiler/assembler/linker bugs |
| 2052 | and mismatches wrt padding and alignment of debug sections. */ |
| 2053 | /* Note that there is no requirement in the standard for any |
| 2054 | alignment at all in the frame unwind sections. Testing for |
| 2055 | alignment before trying to interpret data would be incorrect. |
| 2056 | |
| 2057 | However, GCC traditionally arranged for frame sections to be |
| 2058 | sized such that the FDE length and CIE fields happen to be |
| 2059 | aligned (in theory, for performance). This, unfortunately, |
| 2060 | was done with .align directives, which had the side effect of |
| 2061 | forcing the section to be aligned by the linker. |
| 2062 | |
| 2063 | This becomes a problem when you have some other producer that |
| 2064 | creates frame sections that are not as strictly aligned. That |
| 2065 | produces a hole in the frame info that gets filled by the |
| 2066 | linker with zeros. |
| 2067 | |
| 2068 | The GCC behaviour is arguably a bug, but it's effectively now |
| 2069 | part of the ABI, so we're now stuck with it, at least at the |
| 2070 | object file level. A smart linker may decide, in the process |
| 2071 | of compressing duplicate CIE information, that it can rewrite |
| 2072 | the entire output section without this extra padding. */ |
| 2073 | |
| 2074 | start_offset = start - unit->dwarf_frame_buffer; |
| 2075 | if (workaround < ALIGN4 && (start_offset & 3) != 0) |
| 2076 | { |
| 2077 | start += 4 - (start_offset & 3); |
| 2078 | workaround = ALIGN4; |
| 2079 | continue; |
| 2080 | } |
| 2081 | if (workaround < ALIGN8 && (start_offset & 7) != 0) |
| 2082 | { |
| 2083 | start += 8 - (start_offset & 7); |
| 2084 | workaround = ALIGN8; |
| 2085 | continue; |
| 2086 | } |
| 2087 | |
| 2088 | /* Nothing left to try. Arrange to return as if we've consumed |
| 2089 | the entire input section. Hopefully we'll get valid info from |
| 2090 | the other of .debug_frame/.eh_frame. */ |
| 2091 | workaround = FAIL; |
| 2092 | ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size; |
| 2093 | break; |
| 2094 | } |
| 2095 | |
| 2096 | switch (workaround) |
| 2097 | { |
| 2098 | case NONE: |
| 2099 | break; |
| 2100 | |
| 2101 | case ALIGN4: |
| 2102 | complaint (_("\ |
| 2103 | Corrupt data in %s:%s; align 4 workaround apparently succeeded"), |
| 2104 | unit->dwarf_frame_section->owner->filename, |
| 2105 | unit->dwarf_frame_section->name); |
| 2106 | break; |
| 2107 | |
| 2108 | case ALIGN8: |
| 2109 | complaint (_("\ |
| 2110 | Corrupt data in %s:%s; align 8 workaround apparently succeeded"), |
| 2111 | unit->dwarf_frame_section->owner->filename, |
| 2112 | unit->dwarf_frame_section->name); |
| 2113 | break; |
| 2114 | |
| 2115 | default: |
| 2116 | complaint (_("Corrupt data in %s:%s"), |
| 2117 | unit->dwarf_frame_section->owner->filename, |
| 2118 | unit->dwarf_frame_section->name); |
| 2119 | break; |
| 2120 | } |
| 2121 | |
| 2122 | return ret; |
| 2123 | } |
| 2124 | \f |
| 2125 | static bool |
| 2126 | fde_is_less_than (const dwarf2_fde *aa, const dwarf2_fde *bb) |
| 2127 | { |
| 2128 | if (aa->initial_location == bb->initial_location) |
| 2129 | { |
| 2130 | if (aa->address_range != bb->address_range |
| 2131 | && aa->eh_frame_p == 0 && bb->eh_frame_p == 0) |
| 2132 | /* Linker bug, e.g. gold/10400. |
| 2133 | Work around it by keeping stable sort order. */ |
| 2134 | return aa < bb; |
| 2135 | else |
| 2136 | /* Put eh_frame entries after debug_frame ones. */ |
| 2137 | return aa->eh_frame_p < bb->eh_frame_p; |
| 2138 | } |
| 2139 | |
| 2140 | return aa->initial_location < bb->initial_location; |
| 2141 | } |
| 2142 | |
| 2143 | void |
| 2144 | dwarf2_build_frame_info (struct objfile *objfile) |
| 2145 | { |
| 2146 | const gdb_byte *frame_ptr; |
| 2147 | dwarf2_cie_table cie_table; |
| 2148 | dwarf2_fde_table fde_table; |
| 2149 | |
| 2150 | struct gdbarch *gdbarch = objfile->arch (); |
| 2151 | |
| 2152 | /* Build a minimal decoding of the DWARF2 compilation unit. */ |
| 2153 | std::unique_ptr<comp_unit> unit (new comp_unit (objfile)); |
| 2154 | |
| 2155 | if (objfile->separate_debug_objfile_backlink == NULL) |
| 2156 | { |
| 2157 | /* Do not read .eh_frame from separate file as they must be also |
| 2158 | present in the main file. */ |
| 2159 | dwarf2_get_section_info (objfile, DWARF2_EH_FRAME, |
| 2160 | &unit->dwarf_frame_section, |
| 2161 | &unit->dwarf_frame_buffer, |
| 2162 | &unit->dwarf_frame_size); |
| 2163 | if (unit->dwarf_frame_size) |
| 2164 | { |
| 2165 | asection *got, *txt; |
| 2166 | |
| 2167 | /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base |
| 2168 | that is used for the i386/amd64 target, which currently is |
| 2169 | the only target in GCC that supports/uses the |
| 2170 | DW_EH_PE_datarel encoding. */ |
| 2171 | got = bfd_get_section_by_name (unit->abfd, ".got"); |
| 2172 | if (got) |
| 2173 | unit->dbase = got->vma; |
| 2174 | |
| 2175 | /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64 |
| 2176 | so far. */ |
| 2177 | txt = bfd_get_section_by_name (unit->abfd, ".text"); |
| 2178 | if (txt) |
| 2179 | unit->tbase = txt->vma; |
| 2180 | |
| 2181 | try |
| 2182 | { |
| 2183 | frame_ptr = unit->dwarf_frame_buffer; |
| 2184 | while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 2185 | frame_ptr = decode_frame_entry (gdbarch, unit.get (), |
| 2186 | frame_ptr, 1, |
| 2187 | cie_table, &fde_table, |
| 2188 | EH_CIE_OR_FDE_TYPE_ID); |
| 2189 | } |
| 2190 | |
| 2191 | catch (const gdb_exception_error &e) |
| 2192 | { |
| 2193 | warning (_("skipping .eh_frame info of %s: %s"), |
| 2194 | objfile_name (objfile), e.what ()); |
| 2195 | |
| 2196 | fde_table.clear (); |
| 2197 | /* The cie_table is discarded below. */ |
| 2198 | } |
| 2199 | |
| 2200 | cie_table.clear (); |
| 2201 | } |
| 2202 | } |
| 2203 | |
| 2204 | dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME, |
| 2205 | &unit->dwarf_frame_section, |
| 2206 | &unit->dwarf_frame_buffer, |
| 2207 | &unit->dwarf_frame_size); |
| 2208 | if (unit->dwarf_frame_size) |
| 2209 | { |
| 2210 | size_t num_old_fde_entries = fde_table.size (); |
| 2211 | |
| 2212 | try |
| 2213 | { |
| 2214 | frame_ptr = unit->dwarf_frame_buffer; |
| 2215 | while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size) |
| 2216 | frame_ptr = decode_frame_entry (gdbarch, unit.get (), frame_ptr, 0, |
| 2217 | cie_table, &fde_table, |
| 2218 | EH_CIE_OR_FDE_TYPE_ID); |
| 2219 | } |
| 2220 | catch (const gdb_exception_error &e) |
| 2221 | { |
| 2222 | warning (_("skipping .debug_frame info of %s: %s"), |
| 2223 | objfile_name (objfile), e.what ()); |
| 2224 | |
| 2225 | fde_table.resize (num_old_fde_entries); |
| 2226 | } |
| 2227 | } |
| 2228 | |
| 2229 | struct dwarf2_fde *fde_prev = NULL; |
| 2230 | struct dwarf2_fde *first_non_zero_fde = NULL; |
| 2231 | |
| 2232 | /* Prepare FDE table for lookups. */ |
| 2233 | std::sort (fde_table.begin (), fde_table.end (), fde_is_less_than); |
| 2234 | |
| 2235 | /* Check for leftovers from --gc-sections. The GNU linker sets |
| 2236 | the relevant symbols to zero, but doesn't zero the FDE *end* |
| 2237 | ranges because there's no relocation there. It's (offset, |
| 2238 | length), not (start, end). On targets where address zero is |
| 2239 | just another valid address this can be a problem, since the |
| 2240 | FDEs appear to be non-empty in the output --- we could pick |
| 2241 | out the wrong FDE. To work around this, when overlaps are |
| 2242 | detected, we prefer FDEs that do not start at zero. |
| 2243 | |
| 2244 | Start by finding the first FDE with non-zero start. Below |
| 2245 | we'll discard all FDEs that start at zero and overlap this |
| 2246 | one. */ |
| 2247 | for (struct dwarf2_fde *fde : fde_table) |
| 2248 | { |
| 2249 | if (fde->initial_location != 0) |
| 2250 | { |
| 2251 | first_non_zero_fde = fde; |
| 2252 | break; |
| 2253 | } |
| 2254 | } |
| 2255 | |
| 2256 | /* Since we'll be doing bsearch, squeeze out identical (except |
| 2257 | for eh_frame_p) fde entries so bsearch result is predictable. |
| 2258 | Also discard leftovers from --gc-sections. */ |
| 2259 | for (struct dwarf2_fde *fde : fde_table) |
| 2260 | { |
| 2261 | if (fde->initial_location == 0 |
| 2262 | && first_non_zero_fde != NULL |
| 2263 | && (first_non_zero_fde->initial_location |
| 2264 | < fde->initial_location + fde->address_range)) |
| 2265 | continue; |
| 2266 | |
| 2267 | if (fde_prev != NULL |
| 2268 | && fde_prev->initial_location == fde->initial_location) |
| 2269 | continue; |
| 2270 | |
| 2271 | unit->fde_table.push_back (fde); |
| 2272 | fde_prev = fde; |
| 2273 | } |
| 2274 | unit->fde_table.shrink_to_fit (); |
| 2275 | |
| 2276 | set_comp_unit (objfile, unit.release ()); |
| 2277 | } |
| 2278 | |
| 2279 | /* Handle 'maintenance show dwarf unwinders'. */ |
| 2280 | |
| 2281 | static void |
| 2282 | show_dwarf_unwinders_enabled_p (struct ui_file *file, int from_tty, |
| 2283 | struct cmd_list_element *c, |
| 2284 | const char *value) |
| 2285 | { |
| 2286 | fprintf_filtered (file, |
| 2287 | _("The DWARF stack unwinders are currently %s.\n"), |
| 2288 | value); |
| 2289 | } |
| 2290 | |
| 2291 | void _initialize_dwarf2_frame (); |
| 2292 | void |
| 2293 | _initialize_dwarf2_frame () |
| 2294 | { |
| 2295 | dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init); |
| 2296 | |
| 2297 | add_setshow_boolean_cmd ("unwinders", class_obscure, |
| 2298 | &dwarf2_frame_unwinders_enabled_p , _("\ |
| 2299 | Set whether the DWARF stack frame unwinders are used."), _("\ |
| 2300 | Show whether the DWARF stack frame unwinders are used."), _("\ |
| 2301 | When enabled the DWARF stack frame unwinders can be used for architectures\n\ |
| 2302 | that support the DWARF unwinders. Enabling the DWARF unwinders for an\n\ |
| 2303 | architecture that doesn't support them will have no effect."), |
| 2304 | NULL, |
| 2305 | show_dwarf_unwinders_enabled_p, |
| 2306 | &set_dwarf_cmdlist, |
| 2307 | &show_dwarf_cmdlist); |
| 2308 | |
| 2309 | #if GDB_SELF_TEST |
| 2310 | selftests::register_test_foreach_arch ("execute_cfa_program", |
| 2311 | selftests::execute_cfa_program_test); |
| 2312 | #endif |
| 2313 | } |