1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003-2018 Free Software Foundation, Inc.
5 Contributed by Mark Kettenis.
7 This file is part of GDB.
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.
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.
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/>. */
23 #include "dwarf2expr.h"
26 #include "frame-base.h"
27 #include "frame-unwind.h"
36 #include "complaints.h"
37 #include "dwarf2-frame.h"
38 #include "dwarf2read.h"
40 #include "dwarf2loc.h"
41 #include "dwarf2-frame-tailcall.h"
44 #include "selftest-arch.h"
49 /* Call Frame Information (CFI). */
51 /* Common Information Entry (CIE). */
55 /* Computation Unit for this CIE. */
56 struct comp_unit *unit;
58 /* Offset into the .debug_frame section where this CIE was found.
59 Used to identify this CIE. */
62 /* Constant that is factored out of all advance location
64 ULONGEST code_alignment_factor;
66 /* Constants that is factored out of all offset instructions. */
67 LONGEST data_alignment_factor;
69 /* Return address column. */
70 ULONGEST return_address_register;
72 /* Instruction sequence to initialize a register set. */
73 const gdb_byte *initial_instructions;
76 /* Saved augmentation, in case it's needed later. */
79 /* Encoding of addresses. */
82 /* Target address size in bytes. */
85 /* Target pointer size in bytes. */
88 /* True if a 'z' augmentation existed. */
89 unsigned char saw_z_augmentation;
91 /* True if an 'S' augmentation existed. */
92 unsigned char signal_frame;
94 /* The version recorded in the CIE. */
95 unsigned char version;
97 /* The segment size. */
98 unsigned char segment_size;
101 struct dwarf2_cie_table
104 struct dwarf2_cie **entries;
107 /* Frame Description Entry (FDE). */
111 /* CIE for this FDE. */
112 struct dwarf2_cie *cie;
114 /* First location associated with this FDE. */
115 CORE_ADDR initial_location;
117 /* Number of bytes of program instructions described by this FDE. */
118 CORE_ADDR address_range;
120 /* Instruction sequence. */
121 const gdb_byte *instructions;
124 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
126 unsigned char eh_frame_p;
129 struct dwarf2_fde_table
132 struct dwarf2_fde **entries;
135 /* A minimal decoding of DWARF2 compilation units. We only decode
136 what's needed to get to the call frame information. */
140 /* Keep the bfd convenient. */
143 struct objfile *objfile;
145 /* Pointer to the .debug_frame section loaded into memory. */
146 const gdb_byte *dwarf_frame_buffer;
148 /* Length of the loaded .debug_frame section. */
149 bfd_size_type dwarf_frame_size;
151 /* Pointer to the .debug_frame section. */
152 asection *dwarf_frame_section;
154 /* Base for DW_EH_PE_datarel encodings. */
157 /* Base for DW_EH_PE_textrel encodings. */
161 static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc,
162 CORE_ADDR *out_offset);
164 static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
167 static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
168 int ptr_len, const gdb_byte *buf,
169 unsigned int *bytes_read_ptr,
170 CORE_ADDR func_base);
173 /* See dwarf2-frame.h. */
174 int dwarf2_frame_unwinders_enabled_p = 1;
176 /* Store the length the expression for the CFA in the `cfa_reg' field,
177 which is unused in that case. */
178 #define cfa_exp_len cfa_reg
180 dwarf2_frame_state::dwarf2_frame_state (CORE_ADDR pc_, struct dwarf2_cie *cie)
181 : pc (pc_), data_align (cie->data_alignment_factor),
182 code_align (cie->code_alignment_factor),
183 retaddr_column (cie->return_address_register)
188 /* Helper functions for execute_stack_op. */
191 read_addr_from_reg (struct frame_info *this_frame, int reg)
193 struct gdbarch *gdbarch = get_frame_arch (this_frame);
194 int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);
196 return address_from_register (regnum, this_frame);
199 /* Execute the required actions for both the DW_CFA_restore and
200 DW_CFA_restore_extended instructions. */
202 dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
203 struct dwarf2_frame_state *fs, int eh_frame_p)
207 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
208 fs->regs.alloc_regs (reg + 1);
210 /* Check if this register was explicitly initialized in the
211 CIE initial instructions. If not, default the rule to
213 if (reg < fs->initial.reg.size ())
214 fs->regs.reg[reg] = fs->initial.reg[reg];
216 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
218 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
220 int regnum = dwarf_reg_to_regnum (gdbarch, reg);
223 incomplete CFI data; DW_CFA_restore unspecified\n\
224 register %s (#%d) at %s"),
225 gdbarch_register_name (gdbarch, regnum), regnum,
226 paddress (gdbarch, fs->pc));
230 class dwarf_expr_executor : public dwarf_expr_context
234 struct frame_info *this_frame;
236 CORE_ADDR read_addr_from_reg (int reg) override
238 return ::read_addr_from_reg (this_frame, reg);
241 struct value *get_reg_value (struct type *type, int reg) override
243 struct gdbarch *gdbarch = get_frame_arch (this_frame);
244 int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);
246 return value_from_register (type, regnum, this_frame);
249 void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
251 read_memory (addr, buf, len);
254 void get_frame_base (const gdb_byte **start, size_t *length) override
256 invalid ("DW_OP_fbreg");
259 void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
260 union call_site_parameter_u kind_u,
261 int deref_size) override
263 invalid ("DW_OP_entry_value");
266 CORE_ADDR get_object_address () override
268 invalid ("DW_OP_push_object_address");
271 CORE_ADDR get_frame_cfa () override
273 invalid ("DW_OP_call_frame_cfa");
276 CORE_ADDR get_tls_address (CORE_ADDR offset) override
278 invalid ("DW_OP_form_tls_address");
281 void dwarf_call (cu_offset die_offset) override
283 invalid ("DW_OP_call*");
286 struct value *dwarf_variable_value (sect_offset sect_off) override
288 invalid ("DW_OP_GNU_variable_value");
291 CORE_ADDR get_addr_index (unsigned int index) override
293 invalid ("DW_OP_GNU_addr_index");
298 void invalid (const char *op) ATTRIBUTE_NORETURN
300 error (_("%s is invalid in this context"), op);
305 execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
306 CORE_ADDR offset, struct frame_info *this_frame,
307 CORE_ADDR initial, int initial_in_stack_memory)
311 dwarf_expr_executor ctx;
312 scoped_value_mark free_values;
314 ctx.this_frame = this_frame;
315 ctx.gdbarch = get_frame_arch (this_frame);
316 ctx.addr_size = addr_size;
317 ctx.ref_addr_size = -1;
320 ctx.push_address (initial, initial_in_stack_memory);
323 if (ctx.location == DWARF_VALUE_MEMORY)
324 result = ctx.fetch_address (0);
325 else if (ctx.location == DWARF_VALUE_REGISTER)
326 result = ctx.read_addr_from_reg (value_as_long (ctx.fetch (0)));
329 /* This is actually invalid DWARF, but if we ever do run across
330 it somehow, we might as well support it. So, instead, report
331 it as unimplemented. */
333 Not implemented: computing unwound register using explicit value operator"));
340 /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
341 PC. Modify FS state accordingly. Return current INSN_PTR where the
342 execution has stopped, one can resume it on the next call. */
344 static const gdb_byte *
345 execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
346 const gdb_byte *insn_end, struct gdbarch *gdbarch,
347 CORE_ADDR pc, struct dwarf2_frame_state *fs)
349 int eh_frame_p = fde->eh_frame_p;
350 unsigned int bytes_read;
351 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
353 while (insn_ptr < insn_end && fs->pc <= pc)
355 gdb_byte insn = *insn_ptr++;
359 if ((insn & 0xc0) == DW_CFA_advance_loc)
360 fs->pc += (insn & 0x3f) * fs->code_align;
361 else if ((insn & 0xc0) == DW_CFA_offset)
364 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
365 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
366 offset = utmp * fs->data_align;
367 fs->regs.alloc_regs (reg + 1);
368 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
369 fs->regs.reg[reg].loc.offset = offset;
371 else if ((insn & 0xc0) == DW_CFA_restore)
374 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
381 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
382 fde->cie->ptr_size, insn_ptr,
383 &bytes_read, fde->initial_location);
384 /* Apply the objfile offset for relocatable objects. */
385 fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
386 SECT_OFF_TEXT (fde->cie->unit->objfile));
387 insn_ptr += bytes_read;
390 case DW_CFA_advance_loc1:
391 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
392 fs->pc += utmp * fs->code_align;
395 case DW_CFA_advance_loc2:
396 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
397 fs->pc += utmp * fs->code_align;
400 case DW_CFA_advance_loc4:
401 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
402 fs->pc += utmp * fs->code_align;
406 case DW_CFA_offset_extended:
407 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
408 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
409 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
410 offset = utmp * fs->data_align;
411 fs->regs.alloc_regs (reg + 1);
412 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
413 fs->regs.reg[reg].loc.offset = offset;
416 case DW_CFA_restore_extended:
417 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
418 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
421 case DW_CFA_undefined:
422 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
423 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
424 fs->regs.alloc_regs (reg + 1);
425 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
428 case DW_CFA_same_value:
429 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
430 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
431 fs->regs.alloc_regs (reg + 1);
432 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
435 case DW_CFA_register:
436 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
437 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
438 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
439 utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
440 fs->regs.alloc_regs (reg + 1);
441 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
442 fs->regs.reg[reg].loc.reg = utmp;
445 case DW_CFA_remember_state:
447 struct dwarf2_frame_state_reg_info *new_rs;
449 new_rs = new dwarf2_frame_state_reg_info (fs->regs);
450 fs->regs.prev = new_rs;
454 case DW_CFA_restore_state:
456 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
461 bad CFI data; mismatched DW_CFA_restore_state at %s"),
462 paddress (gdbarch, fs->pc));
465 fs->regs = std::move (*old_rs);
470 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
471 fs->regs.cfa_reg = reg;
472 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
474 if (fs->armcc_cfa_offsets_sf)
475 utmp *= fs->data_align;
477 fs->regs.cfa_offset = utmp;
478 fs->regs.cfa_how = CFA_REG_OFFSET;
481 case DW_CFA_def_cfa_register:
482 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
483 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
485 fs->regs.cfa_how = CFA_REG_OFFSET;
488 case DW_CFA_def_cfa_offset:
489 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
491 if (fs->armcc_cfa_offsets_sf)
492 utmp *= fs->data_align;
494 fs->regs.cfa_offset = utmp;
495 /* cfa_how deliberately not set. */
501 case DW_CFA_def_cfa_expression:
502 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
503 fs->regs.cfa_exp_len = utmp;
504 fs->regs.cfa_exp = insn_ptr;
505 fs->regs.cfa_how = CFA_EXP;
506 insn_ptr += fs->regs.cfa_exp_len;
509 case DW_CFA_expression:
510 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
511 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
512 fs->regs.alloc_regs (reg + 1);
513 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
514 fs->regs.reg[reg].loc.exp.start = insn_ptr;
515 fs->regs.reg[reg].loc.exp.len = utmp;
516 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
520 case DW_CFA_offset_extended_sf:
521 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
522 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
523 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
524 offset *= fs->data_align;
525 fs->regs.alloc_regs (reg + 1);
526 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
527 fs->regs.reg[reg].loc.offset = offset;
530 case DW_CFA_val_offset:
531 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
532 fs->regs.alloc_regs (reg + 1);
533 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
534 offset = utmp * fs->data_align;
535 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
536 fs->regs.reg[reg].loc.offset = offset;
539 case DW_CFA_val_offset_sf:
540 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
541 fs->regs.alloc_regs (reg + 1);
542 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
543 offset *= fs->data_align;
544 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
545 fs->regs.reg[reg].loc.offset = offset;
548 case DW_CFA_val_expression:
549 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
550 fs->regs.alloc_regs (reg + 1);
551 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
552 fs->regs.reg[reg].loc.exp.start = insn_ptr;
553 fs->regs.reg[reg].loc.exp.len = utmp;
554 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
558 case DW_CFA_def_cfa_sf:
559 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
560 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
562 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
563 fs->regs.cfa_offset = offset * fs->data_align;
564 fs->regs.cfa_how = CFA_REG_OFFSET;
567 case DW_CFA_def_cfa_offset_sf:
568 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
569 fs->regs.cfa_offset = offset * fs->data_align;
570 /* cfa_how deliberately not set. */
573 case DW_CFA_GNU_args_size:
575 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
578 case DW_CFA_GNU_negative_offset_extended:
579 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
580 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
581 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
582 offset = utmp * fs->data_align;
583 fs->regs.alloc_regs (reg + 1);
584 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
585 fs->regs.reg[reg].loc.offset = -offset;
589 if (insn >= DW_CFA_lo_user && insn <= DW_CFA_hi_user)
591 /* Handle vendor-specific CFI for different architectures. */
592 if (!gdbarch_execute_dwarf_cfa_vendor_op (gdbarch, insn, fs))
593 error (_("Call Frame Instruction op %d in vendor extension "
594 "space is not handled on this architecture."),
598 internal_error (__FILE__, __LINE__,
599 _("Unknown CFI encountered."));
604 if (fs->initial.reg.empty ())
606 /* Don't allow remember/restore between CIE and FDE programs. */
607 delete fs->regs.prev;
608 fs->regs.prev = NULL;
616 namespace selftests {
618 /* Unit test to function execute_cfa_program. */
621 execute_cfa_program_test (struct gdbarch *gdbarch)
623 struct dwarf2_fde fde;
624 struct dwarf2_cie cie;
626 memset (&fde, 0, sizeof fde);
627 memset (&cie, 0, sizeof cie);
629 cie.data_alignment_factor = -4;
630 cie.code_alignment_factor = 2;
633 dwarf2_frame_state fs (0, fde.cie);
637 DW_CFA_def_cfa, 1, 4, /* DW_CFA_def_cfa: r1 ofs 4 */
638 DW_CFA_offset | 0x2, 1, /* DW_CFA_offset: r2 at cfa-4 */
639 DW_CFA_remember_state,
640 DW_CFA_restore_state,
643 const gdb_byte *insn_end = insns + sizeof (insns);
644 const gdb_byte *out = execute_cfa_program (&fde, insns, insn_end, gdbarch,
647 SELF_CHECK (out == insn_end);
648 SELF_CHECK (fs.pc == 0);
650 /* The instructions above only use r1 and r2, but the register numbers
651 used are adjusted by dwarf2_frame_adjust_regnum. */
652 auto r1 = dwarf2_frame_adjust_regnum (gdbarch, 1, fde.eh_frame_p);
653 auto r2 = dwarf2_frame_adjust_regnum (gdbarch, 2, fde.eh_frame_p);
655 SELF_CHECK (fs.regs.reg.size () == (std::max (r1, r2) + 1));
657 SELF_CHECK (fs.regs.reg[r2].how == DWARF2_FRAME_REG_SAVED_OFFSET);
658 SELF_CHECK (fs.regs.reg[r2].loc.offset == -4);
660 for (auto i = 0; i < fs.regs.reg.size (); i++)
662 SELF_CHECK (fs.regs.reg[i].how == DWARF2_FRAME_REG_UNSPECIFIED);
664 SELF_CHECK (fs.regs.cfa_reg == 1);
665 SELF_CHECK (fs.regs.cfa_offset == 4);
666 SELF_CHECK (fs.regs.cfa_how == CFA_REG_OFFSET);
667 SELF_CHECK (fs.regs.cfa_exp == NULL);
668 SELF_CHECK (fs.regs.prev == NULL);
671 } // namespace selftests
672 #endif /* GDB_SELF_TEST */
676 /* Architecture-specific operations. */
678 /* Per-architecture data key. */
679 static struct gdbarch_data *dwarf2_frame_data;
681 struct dwarf2_frame_ops
683 /* Pre-initialize the register state REG for register REGNUM. */
684 void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
685 struct frame_info *);
687 /* Check whether the THIS_FRAME is a signal trampoline. */
688 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
690 /* Convert .eh_frame register number to DWARF register number, or
691 adjust .debug_frame register number. */
692 int (*adjust_regnum) (struct gdbarch *, int, int);
695 /* Default architecture-specific register state initialization
699 dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
700 struct dwarf2_frame_state_reg *reg,
701 struct frame_info *this_frame)
703 /* If we have a register that acts as a program counter, mark it as
704 a destination for the return address. If we have a register that
705 serves as the stack pointer, arrange for it to be filled with the
706 call frame address (CFA). The other registers are marked as
709 We copy the return address to the program counter, since many
710 parts in GDB assume that it is possible to get the return address
711 by unwinding the program counter register. However, on ISA's
712 with a dedicated return address register, the CFI usually only
713 contains information to unwind that return address register.
715 The reason we're treating the stack pointer special here is
716 because in many cases GCC doesn't emit CFI for the stack pointer
717 and implicitly assumes that it is equal to the CFA. This makes
718 some sense since the DWARF specification (version 3, draft 8,
721 "Typically, the CFA is defined to be the value of the stack
722 pointer at the call site in the previous frame (which may be
723 different from its value on entry to the current frame)."
725 However, this isn't true for all platforms supported by GCC
726 (e.g. IBM S/390 and zSeries). Those architectures should provide
727 their own architecture-specific initialization function. */
729 if (regnum == gdbarch_pc_regnum (gdbarch))
730 reg->how = DWARF2_FRAME_REG_RA;
731 else if (regnum == gdbarch_sp_regnum (gdbarch))
732 reg->how = DWARF2_FRAME_REG_CFA;
735 /* Return a default for the architecture-specific operations. */
738 dwarf2_frame_init (struct obstack *obstack)
740 struct dwarf2_frame_ops *ops;
742 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
743 ops->init_reg = dwarf2_frame_default_init_reg;
747 /* Set the architecture-specific register state initialization
748 function for GDBARCH to INIT_REG. */
751 dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
752 void (*init_reg) (struct gdbarch *, int,
753 struct dwarf2_frame_state_reg *,
754 struct frame_info *))
756 struct dwarf2_frame_ops *ops
757 = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);
759 ops->init_reg = init_reg;
762 /* Pre-initialize the register state REG for register REGNUM. */
765 dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
766 struct dwarf2_frame_state_reg *reg,
767 struct frame_info *this_frame)
769 struct dwarf2_frame_ops *ops
770 = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);
772 ops->init_reg (gdbarch, regnum, reg, this_frame);
775 /* Set the architecture-specific signal trampoline recognition
776 function for GDBARCH to SIGNAL_FRAME_P. */
779 dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
780 int (*signal_frame_p) (struct gdbarch *,
781 struct frame_info *))
783 struct dwarf2_frame_ops *ops
784 = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);
786 ops->signal_frame_p = signal_frame_p;
789 /* Query the architecture-specific signal frame recognizer for
793 dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
794 struct frame_info *this_frame)
796 struct dwarf2_frame_ops *ops
797 = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);
799 if (ops->signal_frame_p == NULL)
801 return ops->signal_frame_p (gdbarch, this_frame);
804 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
808 dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
809 int (*adjust_regnum) (struct gdbarch *,
812 struct dwarf2_frame_ops *ops
813 = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);
815 ops->adjust_regnum = adjust_regnum;
818 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
822 dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch,
823 int regnum, int eh_frame_p)
825 struct dwarf2_frame_ops *ops
826 = (struct dwarf2_frame_ops *) gdbarch_data (gdbarch, dwarf2_frame_data);
828 if (ops->adjust_regnum == NULL)
830 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
834 dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
835 struct dwarf2_fde *fde)
837 struct compunit_symtab *cust;
839 cust = find_pc_compunit_symtab (fs->pc);
843 if (producer_is_realview (COMPUNIT_PRODUCER (cust)))
845 if (fde->cie->version == 1)
846 fs->armcc_cfa_offsets_sf = 1;
848 if (fde->cie->version == 1)
849 fs->armcc_cfa_offsets_reversed = 1;
851 /* The reversed offset problem is present in some compilers
852 using DWARF3, but it was eventually fixed. Check the ARM
853 defined augmentations, which are in the format "armcc" followed
854 by a list of one-character options. The "+" option means
855 this problem is fixed (no quirk needed). If the armcc
856 augmentation is missing, the quirk is needed. */
857 if (fde->cie->version == 3
858 && (!startswith (fde->cie->augmentation, "armcc")
859 || strchr (fde->cie->augmentation + 5, '+') == NULL))
860 fs->armcc_cfa_offsets_reversed = 1;
867 /* See dwarf2-frame.h. */
870 dwarf2_fetch_cfa_info (struct gdbarch *gdbarch, CORE_ADDR pc,
871 struct dwarf2_per_cu_data *data,
872 int *regnum_out, LONGEST *offset_out,
873 CORE_ADDR *text_offset_out,
874 const gdb_byte **cfa_start_out,
875 const gdb_byte **cfa_end_out)
877 struct dwarf2_fde *fde;
878 CORE_ADDR text_offset;
881 /* Find the correct FDE. */
882 fde = dwarf2_frame_find_fde (&pc1, &text_offset);
884 error (_("Could not compute CFA; needed to translate this expression"));
886 dwarf2_frame_state fs (pc1, fde->cie);
888 /* Check for "quirks" - known bugs in producers. */
889 dwarf2_frame_find_quirks (&fs, fde);
891 /* First decode all the insns in the CIE. */
892 execute_cfa_program (fde, fde->cie->initial_instructions,
893 fde->cie->end, gdbarch, pc, &fs);
895 /* Save the initialized register set. */
896 fs.initial = fs.regs;
898 /* Then decode the insns in the FDE up to our target PC. */
899 execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);
901 /* Calculate the CFA. */
902 switch (fs.regs.cfa_how)
906 int regnum = dwarf_reg_to_regnum_or_error (gdbarch, fs.regs.cfa_reg);
908 *regnum_out = regnum;
909 if (fs.armcc_cfa_offsets_reversed)
910 *offset_out = -fs.regs.cfa_offset;
912 *offset_out = fs.regs.cfa_offset;
917 *text_offset_out = text_offset;
918 *cfa_start_out = fs.regs.cfa_exp;
919 *cfa_end_out = fs.regs.cfa_exp + fs.regs.cfa_exp_len;
923 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
928 struct dwarf2_frame_cache
930 /* DWARF Call Frame Address. */
933 /* Set if the return address column was marked as unavailable
934 (required non-collected memory or registers to compute). */
935 int unavailable_retaddr;
937 /* Set if the return address column was marked as undefined. */
938 int undefined_retaddr;
940 /* Saved registers, indexed by GDB register number, not by DWARF
942 struct dwarf2_frame_state_reg *reg;
944 /* Return address register. */
945 struct dwarf2_frame_state_reg retaddr_reg;
947 /* Target address size in bytes. */
950 /* The .text offset. */
951 CORE_ADDR text_offset;
953 /* True if we already checked whether this frame is the bottom frame
954 of a virtual tail call frame chain. */
955 int checked_tailcall_bottom;
957 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
958 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
959 involved. Non-bottom frames of a virtual tail call frames chain use
960 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
962 void *tailcall_cache;
964 /* The number of bytes to subtract from TAILCALL_FRAME frames frame
965 base to get the SP, to simulate the return address pushed on the
967 LONGEST entry_cfa_sp_offset;
968 int entry_cfa_sp_offset_p;
971 static struct dwarf2_frame_cache *
972 dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
974 struct gdbarch *gdbarch = get_frame_arch (this_frame);
975 const int num_regs = gdbarch_num_regs (gdbarch)
976 + gdbarch_num_pseudo_regs (gdbarch);
977 struct dwarf2_frame_cache *cache;
978 struct dwarf2_fde *fde;
980 const gdb_byte *instr;
983 return (struct dwarf2_frame_cache *) *this_cache;
985 /* Allocate a new cache. */
986 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
987 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
992 Note that if the next frame is never supposed to return (i.e. a call
993 to abort), the compiler might optimize away the instruction at
994 its return address. As a result the return address will
995 point at some random instruction, and the CFI for that
996 instruction is probably worthless to us. GCC's unwinder solves
997 this problem by substracting 1 from the return address to get an
998 address in the middle of a presumed call instruction (or the
999 instruction in the associated delay slot). This should only be
1000 done for "normal" frames and not for resume-type frames (signal
1001 handlers, sentinel frames, dummy frames). The function
1002 get_frame_address_in_block does just this. It's not clear how
1003 reliable the method is though; there is the potential for the
1004 register state pre-call being different to that on return. */
1005 CORE_ADDR pc1 = get_frame_address_in_block (this_frame);
1007 /* Find the correct FDE. */
1008 fde = dwarf2_frame_find_fde (&pc1, &cache->text_offset);
1009 gdb_assert (fde != NULL);
1011 /* Allocate and initialize the frame state. */
1012 struct dwarf2_frame_state fs (pc1, fde->cie);
1014 cache->addr_size = fde->cie->addr_size;
1016 /* Check for "quirks" - known bugs in producers. */
1017 dwarf2_frame_find_quirks (&fs, fde);
1019 /* First decode all the insns in the CIE. */
1020 execute_cfa_program (fde, fde->cie->initial_instructions,
1021 fde->cie->end, gdbarch,
1022 get_frame_address_in_block (this_frame), &fs);
1024 /* Save the initialized register set. */
1025 fs.initial = fs.regs;
1027 if (get_frame_func_if_available (this_frame, &entry_pc))
1029 /* Decode the insns in the FDE up to the entry PC. */
1030 instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
1033 if (fs.regs.cfa_how == CFA_REG_OFFSET
1034 && (dwarf_reg_to_regnum (gdbarch, fs.regs.cfa_reg)
1035 == gdbarch_sp_regnum (gdbarch)))
1037 cache->entry_cfa_sp_offset = fs.regs.cfa_offset;
1038 cache->entry_cfa_sp_offset_p = 1;
1042 instr = fde->instructions;
1044 /* Then decode the insns in the FDE up to our target PC. */
1045 execute_cfa_program (fde, instr, fde->end, gdbarch,
1046 get_frame_address_in_block (this_frame), &fs);
1050 /* Calculate the CFA. */
1051 switch (fs.regs.cfa_how)
1053 case CFA_REG_OFFSET:
1054 cache->cfa = read_addr_from_reg (this_frame, fs.regs.cfa_reg);
1055 if (fs.armcc_cfa_offsets_reversed)
1056 cache->cfa -= fs.regs.cfa_offset;
1058 cache->cfa += fs.regs.cfa_offset;
1063 execute_stack_op (fs.regs.cfa_exp, fs.regs.cfa_exp_len,
1064 cache->addr_size, cache->text_offset,
1069 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
1072 CATCH (ex, RETURN_MASK_ERROR)
1074 if (ex.error == NOT_AVAILABLE_ERROR)
1076 cache->unavailable_retaddr = 1;
1080 throw_exception (ex);
1084 /* Initialize the register state. */
1088 for (regnum = 0; regnum < num_regs; regnum++)
1089 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
1092 /* Go through the DWARF2 CFI generated table and save its register
1093 location information in the cache. Note that we don't skip the
1094 return address column; it's perfectly all right for it to
1095 correspond to a real register. */
1097 int column; /* CFI speak for "register number". */
1099 for (column = 0; column < fs.regs.reg.size (); column++)
1101 /* Use the GDB register number as the destination index. */
1102 int regnum = dwarf_reg_to_regnum (gdbarch, column);
1104 /* Protect against a target returning a bad register. */
1105 if (regnum < 0 || regnum >= num_regs)
1108 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1109 of all debug info registers. If it doesn't, complain (but
1110 not too loudly). It turns out that GCC assumes that an
1111 unspecified register implies "same value" when CFI (draft
1112 7) specifies nothing at all. Such a register could equally
1113 be interpreted as "undefined". Also note that this check
1114 isn't sufficient; it only checks that all registers in the
1115 range [0 .. max column] are specified, and won't detect
1116 problems when a debug info register falls outside of the
1117 table. We need a way of iterating through all the valid
1118 DWARF2 register numbers. */
1119 if (fs.regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1121 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1123 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1124 gdbarch_register_name (gdbarch, regnum),
1125 paddress (gdbarch, fs.pc));
1128 cache->reg[regnum] = fs.regs.reg[column];
1132 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1133 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1137 for (regnum = 0; regnum < num_regs; regnum++)
1139 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1140 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1142 const std::vector<struct dwarf2_frame_state_reg> ®s
1144 ULONGEST retaddr_column = fs.retaddr_column;
1146 /* It seems rather bizarre to specify an "empty" column as
1147 the return adress column. However, this is exactly
1148 what GCC does on some targets. It turns out that GCC
1149 assumes that the return address can be found in the
1150 register corresponding to the return address column.
1151 Incidentally, that's how we should treat a return
1152 address column specifying "same value" too. */
1153 if (fs.retaddr_column < fs.regs.reg.size ()
1154 && regs[retaddr_column].how != DWARF2_FRAME_REG_UNSPECIFIED
1155 && regs[retaddr_column].how != DWARF2_FRAME_REG_SAME_VALUE)
1157 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1158 cache->reg[regnum] = regs[retaddr_column];
1160 cache->retaddr_reg = regs[retaddr_column];
1164 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1166 cache->reg[regnum].loc.reg = fs.retaddr_column;
1167 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1171 cache->retaddr_reg.loc.reg = fs.retaddr_column;
1172 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1179 if (fs.retaddr_column < fs.regs.reg.size ()
1180 && fs.regs.reg[fs.retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1181 cache->undefined_retaddr = 1;
1186 static enum unwind_stop_reason
1187 dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame,
1190 struct dwarf2_frame_cache *cache
1191 = dwarf2_frame_cache (this_frame, this_cache);
1193 if (cache->unavailable_retaddr)
1194 return UNWIND_UNAVAILABLE;
1196 if (cache->undefined_retaddr)
1197 return UNWIND_OUTERMOST;
1199 return UNWIND_NO_REASON;
1203 dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1204 struct frame_id *this_id)
1206 struct dwarf2_frame_cache *cache =
1207 dwarf2_frame_cache (this_frame, this_cache);
1209 if (cache->unavailable_retaddr)
1210 (*this_id) = frame_id_build_unavailable_stack (get_frame_func (this_frame));
1211 else if (cache->undefined_retaddr)
1214 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1217 static struct value *
1218 dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1221 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1222 struct dwarf2_frame_cache *cache =
1223 dwarf2_frame_cache (this_frame, this_cache);
1227 /* Check whether THIS_FRAME is the bottom frame of a virtual tail
1228 call frame chain. */
1229 if (!cache->checked_tailcall_bottom)
1231 cache->checked_tailcall_bottom = 1;
1232 dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache,
1233 (cache->entry_cfa_sp_offset_p
1234 ? &cache->entry_cfa_sp_offset : NULL));
1237 /* Non-bottom frames of a virtual tail call frames chain use
1238 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1239 them. If dwarf2_tailcall_prev_register_first does not have specific value
1240 unwind the register, tail call frames are assumed to have the register set
1241 of the top caller. */
1242 if (cache->tailcall_cache)
1246 val = dwarf2_tailcall_prev_register_first (this_frame,
1247 &cache->tailcall_cache,
1253 switch (cache->reg[regnum].how)
1255 case DWARF2_FRAME_REG_UNDEFINED:
1256 /* If CFI explicitly specified that the value isn't defined,
1257 mark it as optimized away; the value isn't available. */
1258 return frame_unwind_got_optimized (this_frame, regnum);
1260 case DWARF2_FRAME_REG_SAVED_OFFSET:
1261 addr = cache->cfa + cache->reg[regnum].loc.offset;
1262 return frame_unwind_got_memory (this_frame, regnum, addr);
1264 case DWARF2_FRAME_REG_SAVED_REG:
1265 realnum = dwarf_reg_to_regnum_or_error
1266 (gdbarch, cache->reg[regnum].loc.reg);
1267 return frame_unwind_got_register (this_frame, regnum, realnum);
1269 case DWARF2_FRAME_REG_SAVED_EXP:
1270 addr = execute_stack_op (cache->reg[regnum].loc.exp.start,
1271 cache->reg[regnum].loc.exp.len,
1272 cache->addr_size, cache->text_offset,
1273 this_frame, cache->cfa, 1);
1274 return frame_unwind_got_memory (this_frame, regnum, addr);
1276 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1277 addr = cache->cfa + cache->reg[regnum].loc.offset;
1278 return frame_unwind_got_constant (this_frame, regnum, addr);
1280 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1281 addr = execute_stack_op (cache->reg[regnum].loc.exp.start,
1282 cache->reg[regnum].loc.exp.len,
1283 cache->addr_size, cache->text_offset,
1284 this_frame, cache->cfa, 1);
1285 return frame_unwind_got_constant (this_frame, regnum, addr);
1287 case DWARF2_FRAME_REG_UNSPECIFIED:
1288 /* GCC, in its infinite wisdom decided to not provide unwind
1289 information for registers that are "same value". Since
1290 DWARF2 (3 draft 7) doesn't define such behavior, said
1291 registers are actually undefined (which is different to CFI
1292 "undefined"). Code above issues a complaint about this.
1293 Here just fudge the books, assume GCC, and that the value is
1294 more inner on the stack. */
1295 return frame_unwind_got_register (this_frame, regnum, regnum);
1297 case DWARF2_FRAME_REG_SAME_VALUE:
1298 return frame_unwind_got_register (this_frame, regnum, regnum);
1300 case DWARF2_FRAME_REG_CFA:
1301 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1303 case DWARF2_FRAME_REG_CFA_OFFSET:
1304 addr = cache->cfa + cache->reg[regnum].loc.offset;
1305 return frame_unwind_got_address (this_frame, regnum, addr);
1307 case DWARF2_FRAME_REG_RA_OFFSET:
1308 addr = cache->reg[regnum].loc.offset;
1309 regnum = dwarf_reg_to_regnum_or_error
1310 (gdbarch, cache->retaddr_reg.loc.reg);
1311 addr += get_frame_register_unsigned (this_frame, regnum);
1312 return frame_unwind_got_address (this_frame, regnum, addr);
1314 case DWARF2_FRAME_REG_FN:
1315 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1318 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1322 /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1323 call frames chain. */
1326 dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache)
1328 struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache);
1330 if (cache->tailcall_cache)
1331 dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache);
1335 dwarf2_frame_sniffer (const struct frame_unwind *self,
1336 struct frame_info *this_frame, void **this_cache)
1338 if (!dwarf2_frame_unwinders_enabled_p)
1341 /* Grab an address that is guarenteed to reside somewhere within the
1342 function. get_frame_pc(), with a no-return next function, can
1343 end up returning something past the end of this function's body.
1344 If the frame we're sniffing for is a signal frame whose start
1345 address is placed on the stack by the OS, its FDE must
1346 extend one byte before its start address or we could potentially
1347 select the FDE of the previous function. */
1348 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1349 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL);
1354 /* On some targets, signal trampolines may have unwind information.
1355 We need to recognize them so that we set the frame type
1358 if (fde->cie->signal_frame
1359 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1361 return self->type == SIGTRAMP_FRAME;
1363 if (self->type != NORMAL_FRAME)
1369 static const struct frame_unwind dwarf2_frame_unwind =
1372 dwarf2_frame_unwind_stop_reason,
1373 dwarf2_frame_this_id,
1374 dwarf2_frame_prev_register,
1376 dwarf2_frame_sniffer,
1377 dwarf2_frame_dealloc_cache
1380 static const struct frame_unwind dwarf2_signal_frame_unwind =
1383 dwarf2_frame_unwind_stop_reason,
1384 dwarf2_frame_this_id,
1385 dwarf2_frame_prev_register,
1387 dwarf2_frame_sniffer,
1389 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1393 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1396 dwarf2_append_unwinders (struct gdbarch *gdbarch)
1398 /* TAILCALL_FRAME must be first to find the record by
1399 dwarf2_tailcall_sniffer_first. */
1400 frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind);
1402 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1403 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1407 /* There is no explicitly defined relationship between the CFA and the
1408 location of frame's local variables and arguments/parameters.
1409 Therefore, frame base methods on this page should probably only be
1410 used as a last resort, just to avoid printing total garbage as a
1411 response to the "info frame" command. */
1414 dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1416 struct dwarf2_frame_cache *cache =
1417 dwarf2_frame_cache (this_frame, this_cache);
1422 static const struct frame_base dwarf2_frame_base =
1424 &dwarf2_frame_unwind,
1425 dwarf2_frame_base_address,
1426 dwarf2_frame_base_address,
1427 dwarf2_frame_base_address
1430 const struct frame_base *
1431 dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1433 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1435 if (dwarf2_frame_find_fde (&block_addr, NULL))
1436 return &dwarf2_frame_base;
1441 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1442 the DWARF unwinder. This is used to implement
1443 DW_OP_call_frame_cfa. */
1446 dwarf2_frame_cfa (struct frame_info *this_frame)
1448 if (frame_unwinder_is (this_frame, &record_btrace_tailcall_frame_unwind)
1449 || frame_unwinder_is (this_frame, &record_btrace_frame_unwind))
1450 throw_error (NOT_AVAILABLE_ERROR,
1451 _("cfa not available for record btrace target"));
1453 while (get_frame_type (this_frame) == INLINE_FRAME)
1454 this_frame = get_prev_frame (this_frame);
1455 if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE)
1456 throw_error (NOT_AVAILABLE_ERROR,
1457 _("can't compute CFA for this frame: "
1458 "required registers or memory are unavailable"));
1460 if (get_frame_id (this_frame).stack_status != FID_STACK_VALID)
1461 throw_error (NOT_AVAILABLE_ERROR,
1462 _("can't compute CFA for this frame: "
1463 "frame base not available"));
1465 return get_frame_base (this_frame);
1468 const struct objfile_data *dwarf2_frame_objfile_data;
1471 read_1_byte (bfd *abfd, const gdb_byte *buf)
1473 return bfd_get_8 (abfd, buf);
1477 read_4_bytes (bfd *abfd, const gdb_byte *buf)
1479 return bfd_get_32 (abfd, buf);
1483 read_8_bytes (bfd *abfd, const gdb_byte *buf)
1485 return bfd_get_64 (abfd, buf);
1489 read_initial_length (bfd *abfd, const gdb_byte *buf,
1490 unsigned int *bytes_read_ptr)
1494 result = bfd_get_32 (abfd, buf);
1495 if (result == 0xffffffff)
1497 result = bfd_get_64 (abfd, buf + 4);
1498 *bytes_read_ptr = 12;
1501 *bytes_read_ptr = 4;
1507 /* Pointer encoding helper functions. */
1509 /* GCC supports exception handling based on DWARF2 CFI. However, for
1510 technical reasons, it encodes addresses in its FDE's in a different
1511 way. Several "pointer encodings" are supported. The encoding
1512 that's used for a particular FDE is determined by the 'R'
1513 augmentation in the associated CIE. The argument of this
1514 augmentation is a single byte.
1516 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1517 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1518 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1519 address should be interpreted (absolute, relative to the current
1520 position in the FDE, ...). Bit 7, indicates that the address
1521 should be dereferenced. */
1524 encoding_for_size (unsigned int size)
1529 return DW_EH_PE_udata2;
1531 return DW_EH_PE_udata4;
1533 return DW_EH_PE_udata8;
1535 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1540 read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
1541 int ptr_len, const gdb_byte *buf,
1542 unsigned int *bytes_read_ptr,
1543 CORE_ADDR func_base)
1548 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1550 if (encoding & DW_EH_PE_indirect)
1551 internal_error (__FILE__, __LINE__,
1552 _("Unsupported encoding: DW_EH_PE_indirect"));
1554 *bytes_read_ptr = 0;
1556 switch (encoding & 0x70)
1558 case DW_EH_PE_absptr:
1561 case DW_EH_PE_pcrel:
1562 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1563 base += (buf - unit->dwarf_frame_buffer);
1565 case DW_EH_PE_datarel:
1568 case DW_EH_PE_textrel:
1571 case DW_EH_PE_funcrel:
1574 case DW_EH_PE_aligned:
1576 offset = buf - unit->dwarf_frame_buffer;
1577 if ((offset % ptr_len) != 0)
1579 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1580 buf += *bytes_read_ptr;
1584 internal_error (__FILE__, __LINE__,
1585 _("Invalid or unsupported encoding"));
1588 if ((encoding & 0x07) == 0x00)
1590 encoding |= encoding_for_size (ptr_len);
1591 if (bfd_get_sign_extend_vma (unit->abfd))
1592 encoding |= DW_EH_PE_signed;
1595 switch (encoding & 0x0f)
1597 case DW_EH_PE_uleb128:
1600 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1602 *bytes_read_ptr += safe_read_uleb128 (buf, end_buf, &value) - buf;
1603 return base + value;
1605 case DW_EH_PE_udata2:
1606 *bytes_read_ptr += 2;
1607 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1608 case DW_EH_PE_udata4:
1609 *bytes_read_ptr += 4;
1610 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1611 case DW_EH_PE_udata8:
1612 *bytes_read_ptr += 8;
1613 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1614 case DW_EH_PE_sleb128:
1617 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1619 *bytes_read_ptr += safe_read_sleb128 (buf, end_buf, &value) - buf;
1620 return base + value;
1622 case DW_EH_PE_sdata2:
1623 *bytes_read_ptr += 2;
1624 return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
1625 case DW_EH_PE_sdata4:
1626 *bytes_read_ptr += 4;
1627 return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
1628 case DW_EH_PE_sdata8:
1629 *bytes_read_ptr += 8;
1630 return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
1632 internal_error (__FILE__, __LINE__,
1633 _("Invalid or unsupported encoding"));
1639 bsearch_cie_cmp (const void *key, const void *element)
1641 ULONGEST cie_pointer = *(ULONGEST *) key;
1642 struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;
1644 if (cie_pointer == cie->cie_pointer)
1647 return (cie_pointer < cie->cie_pointer) ? -1 : 1;
1650 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1651 static struct dwarf2_cie *
1652 find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
1654 struct dwarf2_cie **p_cie;
1656 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1657 bsearch be non-NULL. */
1658 if (cie_table->entries == NULL)
1660 gdb_assert (cie_table->num_entries == 0);
1664 p_cie = ((struct dwarf2_cie **)
1665 bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1666 sizeof (cie_table->entries[0]), bsearch_cie_cmp));
1672 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1674 add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1676 const int n = cie_table->num_entries;
1679 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1682 = XRESIZEVEC (struct dwarf2_cie *, cie_table->entries, n + 1);
1683 cie_table->entries[n] = cie;
1684 cie_table->num_entries = n + 1;
1688 bsearch_fde_cmp (const void *key, const void *element)
1690 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1691 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
1693 if (seek_pc < fde->initial_location)
1695 if (seek_pc < fde->initial_location + fde->address_range)
1700 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1701 inital location associated with it into *PC. */
1703 static struct dwarf2_fde *
1704 dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset)
1706 struct objfile *objfile;
1708 ALL_OBJFILES (objfile)
1710 struct dwarf2_fde_table *fde_table;
1711 struct dwarf2_fde **p_fde;
1715 fde_table = ((struct dwarf2_fde_table *)
1716 objfile_data (objfile, dwarf2_frame_objfile_data));
1717 if (fde_table == NULL)
1719 dwarf2_build_frame_info (objfile);
1720 fde_table = ((struct dwarf2_fde_table *)
1721 objfile_data (objfile, dwarf2_frame_objfile_data));
1723 gdb_assert (fde_table != NULL);
1725 if (fde_table->num_entries == 0)
1728 gdb_assert (objfile->section_offsets);
1729 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1731 gdb_assert (fde_table->num_entries > 0);
1732 if (*pc < offset + fde_table->entries[0]->initial_location)
1735 seek_pc = *pc - offset;
1736 p_fde = ((struct dwarf2_fde **)
1737 bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1738 sizeof (fde_table->entries[0]), bsearch_fde_cmp));
1741 *pc = (*p_fde)->initial_location + offset;
1743 *out_offset = offset;
1750 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1752 add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1754 if (fde->address_range == 0)
1755 /* Discard useless FDEs. */
1758 fde_table->num_entries += 1;
1759 fde_table->entries = XRESIZEVEC (struct dwarf2_fde *, fde_table->entries,
1760 fde_table->num_entries);
1761 fde_table->entries[fde_table->num_entries - 1] = fde;
1764 #define DW64_CIE_ID 0xffffffffffffffffULL
1766 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1771 EH_CIE_TYPE_ID = 1 << 0,
1772 EH_FDE_TYPE_ID = 1 << 1,
1773 EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID
1776 static const gdb_byte *decode_frame_entry (struct comp_unit *unit,
1777 const gdb_byte *start,
1779 struct dwarf2_cie_table *cie_table,
1780 struct dwarf2_fde_table *fde_table,
1781 enum eh_frame_type entry_type);
1783 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1784 Return NULL if invalid input, otherwise the next byte to be processed. */
1786 static const gdb_byte *
1787 decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start,
1789 struct dwarf2_cie_table *cie_table,
1790 struct dwarf2_fde_table *fde_table,
1791 enum eh_frame_type entry_type)
1793 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
1794 const gdb_byte *buf, *end;
1796 unsigned int bytes_read;
1799 ULONGEST cie_pointer;
1804 length = read_initial_length (unit->abfd, buf, &bytes_read);
1808 /* Are we still within the section? */
1809 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1815 /* Distinguish between 32 and 64-bit encoded frame info. */
1816 dwarf64_p = (bytes_read == 12);
1818 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1822 cie_id = DW64_CIE_ID;
1828 cie_pointer = read_8_bytes (unit->abfd, buf);
1833 cie_pointer = read_4_bytes (unit->abfd, buf);
1837 if (cie_pointer == cie_id)
1839 /* This is a CIE. */
1840 struct dwarf2_cie *cie;
1842 unsigned int cie_version;
1844 /* Check that a CIE was expected. */
1845 if ((entry_type & EH_CIE_TYPE_ID) == 0)
1846 error (_("Found a CIE when not expecting it."));
1848 /* Record the offset into the .debug_frame section of this CIE. */
1849 cie_pointer = start - unit->dwarf_frame_buffer;
1851 /* Check whether we've already read it. */
1852 if (find_cie (cie_table, cie_pointer))
1855 cie = XOBNEW (&unit->objfile->objfile_obstack, struct dwarf2_cie);
1856 cie->initial_instructions = NULL;
1857 cie->cie_pointer = cie_pointer;
1859 /* The encoding for FDE's in a normal .debug_frame section
1860 depends on the target address size. */
1861 cie->encoding = DW_EH_PE_absptr;
1863 /* We'll determine the final value later, but we need to
1864 initialize it conservatively. */
1865 cie->signal_frame = 0;
1867 /* Check version number. */
1868 cie_version = read_1_byte (unit->abfd, buf);
1869 if (cie_version != 1 && cie_version != 3 && cie_version != 4)
1871 cie->version = cie_version;
1874 /* Interpret the interesting bits of the augmentation. */
1875 cie->augmentation = augmentation = (char *) buf;
1876 buf += (strlen (augmentation) + 1);
1878 /* Ignore armcc augmentations. We only use them for quirks,
1879 and that doesn't happen until later. */
1880 if (startswith (augmentation, "armcc"))
1881 augmentation += strlen (augmentation);
1883 /* The GCC 2.x "eh" augmentation has a pointer immediately
1884 following the augmentation string, so it must be handled
1886 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1889 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1893 if (cie->version >= 4)
1895 /* FIXME: check that this is the same as from the CU header. */
1896 cie->addr_size = read_1_byte (unit->abfd, buf);
1898 cie->segment_size = read_1_byte (unit->abfd, buf);
1903 cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch);
1904 cie->segment_size = 0;
1906 /* Address values in .eh_frame sections are defined to have the
1907 target's pointer size. Watchout: This breaks frame info for
1908 targets with pointer size < address size, unless a .debug_frame
1909 section exists as well. */
1911 cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1913 cie->ptr_size = cie->addr_size;
1915 buf = gdb_read_uleb128 (buf, end, &uleb128);
1918 cie->code_alignment_factor = uleb128;
1920 buf = gdb_read_sleb128 (buf, end, &sleb128);
1923 cie->data_alignment_factor = sleb128;
1925 if (cie_version == 1)
1927 cie->return_address_register = read_1_byte (unit->abfd, buf);
1932 buf = gdb_read_uleb128 (buf, end, &uleb128);
1935 cie->return_address_register = uleb128;
1938 cie->return_address_register
1939 = dwarf2_frame_adjust_regnum (gdbarch,
1940 cie->return_address_register,
1943 cie->saw_z_augmentation = (*augmentation == 'z');
1944 if (cie->saw_z_augmentation)
1946 uint64_t uleb_length;
1948 buf = gdb_read_uleb128 (buf, end, &uleb_length);
1951 cie->initial_instructions = buf + uleb_length;
1955 while (*augmentation)
1957 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
1958 if (*augmentation == 'L')
1965 /* "R" indicates a byte indicating how FDE addresses are encoded. */
1966 else if (*augmentation == 'R')
1968 cie->encoding = *buf++;
1972 /* "P" indicates a personality routine in the CIE augmentation. */
1973 else if (*augmentation == 'P')
1975 /* Skip. Avoid indirection since we throw away the result. */
1976 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
1977 read_encoded_value (unit, encoding, cie->ptr_size,
1978 buf, &bytes_read, 0);
1983 /* "S" indicates a signal frame, such that the return
1984 address must not be decremented to locate the call frame
1985 info for the previous frame; it might even be the first
1986 instruction of a function, so decrementing it would take
1987 us to a different function. */
1988 else if (*augmentation == 'S')
1990 cie->signal_frame = 1;
1994 /* Otherwise we have an unknown augmentation. Assume that either
1995 there is no augmentation data, or we saw a 'z' prefix. */
1998 if (cie->initial_instructions)
1999 buf = cie->initial_instructions;
2004 cie->initial_instructions = buf;
2008 add_cie (cie_table, cie);
2012 /* This is a FDE. */
2013 struct dwarf2_fde *fde;
2016 /* Check that an FDE was expected. */
2017 if ((entry_type & EH_FDE_TYPE_ID) == 0)
2018 error (_("Found an FDE when not expecting it."));
2020 /* In an .eh_frame section, the CIE pointer is the delta between the
2021 address within the FDE where the CIE pointer is stored and the
2022 address of the CIE. Convert it to an offset into the .eh_frame
2026 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
2027 cie_pointer -= (dwarf64_p ? 8 : 4);
2030 /* In either case, validate the result is still within the section. */
2031 if (cie_pointer >= unit->dwarf_frame_size)
2034 fde = XOBNEW (&unit->objfile->objfile_obstack, struct dwarf2_fde);
2035 fde->cie = find_cie (cie_table, cie_pointer);
2036 if (fde->cie == NULL)
2038 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
2039 eh_frame_p, cie_table, fde_table,
2041 fde->cie = find_cie (cie_table, cie_pointer);
2044 gdb_assert (fde->cie != NULL);
2046 addr = read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
2047 buf, &bytes_read, 0);
2048 fde->initial_location = gdbarch_adjust_dwarf2_addr (gdbarch, addr);
2051 fde->address_range =
2052 read_encoded_value (unit, fde->cie->encoding & 0x0f,
2053 fde->cie->ptr_size, buf, &bytes_read, 0);
2054 addr = gdbarch_adjust_dwarf2_addr (gdbarch, addr + fde->address_range);
2055 fde->address_range = addr - fde->initial_location;
2058 /* A 'z' augmentation in the CIE implies the presence of an
2059 augmentation field in the FDE as well. The only thing known
2060 to be in here at present is the LSDA entry for EH. So we
2061 can skip the whole thing. */
2062 if (fde->cie->saw_z_augmentation)
2064 uint64_t uleb_length;
2066 buf = gdb_read_uleb128 (buf, end, &uleb_length);
2074 fde->instructions = buf;
2077 fde->eh_frame_p = eh_frame_p;
2079 add_fde (fde_table, fde);
2085 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2086 expect an FDE or a CIE. */
2088 static const gdb_byte *
2089 decode_frame_entry (struct comp_unit *unit, const gdb_byte *start,
2091 struct dwarf2_cie_table *cie_table,
2092 struct dwarf2_fde_table *fde_table,
2093 enum eh_frame_type entry_type)
2095 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
2096 const gdb_byte *ret;
2097 ptrdiff_t start_offset;
2101 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
2102 cie_table, fde_table, entry_type);
2106 /* We have corrupt input data of some form. */
2108 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2109 and mismatches wrt padding and alignment of debug sections. */
2110 /* Note that there is no requirement in the standard for any
2111 alignment at all in the frame unwind sections. Testing for
2112 alignment before trying to interpret data would be incorrect.
2114 However, GCC traditionally arranged for frame sections to be
2115 sized such that the FDE length and CIE fields happen to be
2116 aligned (in theory, for performance). This, unfortunately,
2117 was done with .align directives, which had the side effect of
2118 forcing the section to be aligned by the linker.
2120 This becomes a problem when you have some other producer that
2121 creates frame sections that are not as strictly aligned. That
2122 produces a hole in the frame info that gets filled by the
2125 The GCC behaviour is arguably a bug, but it's effectively now
2126 part of the ABI, so we're now stuck with it, at least at the
2127 object file level. A smart linker may decide, in the process
2128 of compressing duplicate CIE information, that it can rewrite
2129 the entire output section without this extra padding. */
2131 start_offset = start - unit->dwarf_frame_buffer;
2132 if (workaround < ALIGN4 && (start_offset & 3) != 0)
2134 start += 4 - (start_offset & 3);
2135 workaround = ALIGN4;
2138 if (workaround < ALIGN8 && (start_offset & 7) != 0)
2140 start += 8 - (start_offset & 7);
2141 workaround = ALIGN8;
2145 /* Nothing left to try. Arrange to return as if we've consumed
2146 the entire input section. Hopefully we'll get valid info from
2147 the other of .debug_frame/.eh_frame. */
2149 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
2160 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2161 unit->dwarf_frame_section->owner->filename,
2162 unit->dwarf_frame_section->name);
2167 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2168 unit->dwarf_frame_section->owner->filename,
2169 unit->dwarf_frame_section->name);
2173 complaint (_("Corrupt data in %s:%s"),
2174 unit->dwarf_frame_section->owner->filename,
2175 unit->dwarf_frame_section->name);
2183 qsort_fde_cmp (const void *a, const void *b)
2185 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
2186 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
2188 if (aa->initial_location == bb->initial_location)
2190 if (aa->address_range != bb->address_range
2191 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2192 /* Linker bug, e.g. gold/10400.
2193 Work around it by keeping stable sort order. */
2194 return (a < b) ? -1 : 1;
2196 /* Put eh_frame entries after debug_frame ones. */
2197 return aa->eh_frame_p - bb->eh_frame_p;
2200 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2204 dwarf2_build_frame_info (struct objfile *objfile)
2206 struct comp_unit *unit;
2207 const gdb_byte *frame_ptr;
2208 struct dwarf2_cie_table cie_table;
2209 struct dwarf2_fde_table fde_table;
2210 struct dwarf2_fde_table *fde_table2;
2212 cie_table.num_entries = 0;
2213 cie_table.entries = NULL;
2215 fde_table.num_entries = 0;
2216 fde_table.entries = NULL;
2218 /* Build a minimal decoding of the DWARF2 compilation unit. */
2219 unit = XOBNEW (&objfile->objfile_obstack, comp_unit);
2220 unit->abfd = objfile->obfd;
2221 unit->objfile = objfile;
2225 if (objfile->separate_debug_objfile_backlink == NULL)
2227 /* Do not read .eh_frame from separate file as they must be also
2228 present in the main file. */
2229 dwarf2_get_section_info (objfile, DWARF2_EH_FRAME,
2230 &unit->dwarf_frame_section,
2231 &unit->dwarf_frame_buffer,
2232 &unit->dwarf_frame_size);
2233 if (unit->dwarf_frame_size)
2235 asection *got, *txt;
2237 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2238 that is used for the i386/amd64 target, which currently is
2239 the only target in GCC that supports/uses the
2240 DW_EH_PE_datarel encoding. */
2241 got = bfd_get_section_by_name (unit->abfd, ".got");
2243 unit->dbase = got->vma;
2245 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2247 txt = bfd_get_section_by_name (unit->abfd, ".text");
2249 unit->tbase = txt->vma;
2253 frame_ptr = unit->dwarf_frame_buffer;
2254 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2255 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2256 &cie_table, &fde_table,
2257 EH_CIE_OR_FDE_TYPE_ID);
2260 CATCH (e, RETURN_MASK_ERROR)
2262 warning (_("skipping .eh_frame info of %s: %s"),
2263 objfile_name (objfile), e.message);
2265 if (fde_table.num_entries != 0)
2267 xfree (fde_table.entries);
2268 fde_table.entries = NULL;
2269 fde_table.num_entries = 0;
2271 /* The cie_table is discarded by the next if. */
2275 if (cie_table.num_entries != 0)
2277 /* Reinit cie_table: debug_frame has different CIEs. */
2278 xfree (cie_table.entries);
2279 cie_table.num_entries = 0;
2280 cie_table.entries = NULL;
2285 dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME,
2286 &unit->dwarf_frame_section,
2287 &unit->dwarf_frame_buffer,
2288 &unit->dwarf_frame_size);
2289 if (unit->dwarf_frame_size)
2291 int num_old_fde_entries = fde_table.num_entries;
2295 frame_ptr = unit->dwarf_frame_buffer;
2296 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2297 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2298 &cie_table, &fde_table,
2299 EH_CIE_OR_FDE_TYPE_ID);
2301 CATCH (e, RETURN_MASK_ERROR)
2303 warning (_("skipping .debug_frame info of %s: %s"),
2304 objfile_name (objfile), e.message);
2306 if (fde_table.num_entries != 0)
2308 fde_table.num_entries = num_old_fde_entries;
2309 if (num_old_fde_entries == 0)
2311 xfree (fde_table.entries);
2312 fde_table.entries = NULL;
2317 = XRESIZEVEC (struct dwarf2_fde *, fde_table.entries,
2318 fde_table.num_entries);
2321 fde_table.num_entries = num_old_fde_entries;
2322 /* The cie_table is discarded by the next if. */
2327 /* Discard the cie_table, it is no longer needed. */
2328 if (cie_table.num_entries != 0)
2330 xfree (cie_table.entries);
2331 cie_table.entries = NULL; /* Paranoia. */
2332 cie_table.num_entries = 0; /* Paranoia. */
2335 /* Copy fde_table to obstack: it is needed at runtime. */
2336 fde_table2 = XOBNEW (&objfile->objfile_obstack, struct dwarf2_fde_table);
2338 if (fde_table.num_entries == 0)
2340 fde_table2->entries = NULL;
2341 fde_table2->num_entries = 0;
2345 struct dwarf2_fde *fde_prev = NULL;
2346 struct dwarf2_fde *first_non_zero_fde = NULL;
2349 /* Prepare FDE table for lookups. */
2350 qsort (fde_table.entries, fde_table.num_entries,
2351 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2353 /* Check for leftovers from --gc-sections. The GNU linker sets
2354 the relevant symbols to zero, but doesn't zero the FDE *end*
2355 ranges because there's no relocation there. It's (offset,
2356 length), not (start, end). On targets where address zero is
2357 just another valid address this can be a problem, since the
2358 FDEs appear to be non-empty in the output --- we could pick
2359 out the wrong FDE. To work around this, when overlaps are
2360 detected, we prefer FDEs that do not start at zero.
2362 Start by finding the first FDE with non-zero start. Below
2363 we'll discard all FDEs that start at zero and overlap this
2365 for (i = 0; i < fde_table.num_entries; i++)
2367 struct dwarf2_fde *fde = fde_table.entries[i];
2369 if (fde->initial_location != 0)
2371 first_non_zero_fde = fde;
2376 /* Since we'll be doing bsearch, squeeze out identical (except
2377 for eh_frame_p) fde entries so bsearch result is predictable.
2378 Also discard leftovers from --gc-sections. */
2379 fde_table2->num_entries = 0;
2380 for (i = 0; i < fde_table.num_entries; i++)
2382 struct dwarf2_fde *fde = fde_table.entries[i];
2384 if (fde->initial_location == 0
2385 && first_non_zero_fde != NULL
2386 && (first_non_zero_fde->initial_location
2387 < fde->initial_location + fde->address_range))
2390 if (fde_prev != NULL
2391 && fde_prev->initial_location == fde->initial_location)
2394 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
2395 sizeof (fde_table.entries[0]));
2396 ++fde_table2->num_entries;
2400 = (struct dwarf2_fde **) obstack_finish (&objfile->objfile_obstack);
2402 /* Discard the original fde_table. */
2403 xfree (fde_table.entries);
2406 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
2409 /* Handle 'maintenance show dwarf unwinders'. */
2412 show_dwarf_unwinders_enabled_p (struct ui_file *file, int from_tty,
2413 struct cmd_list_element *c,
2416 fprintf_filtered (file,
2417 _("The DWARF stack unwinders are currently %s.\n"),
2422 _initialize_dwarf2_frame (void)
2424 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2425 dwarf2_frame_objfile_data = register_objfile_data ();
2427 add_setshow_boolean_cmd ("unwinders", class_obscure,
2428 &dwarf2_frame_unwinders_enabled_p , _("\
2429 Set whether the DWARF stack frame unwinders are used."), _("\
2430 Show whether the DWARF stack frame unwinders are used."), _("\
2431 When enabled the DWARF stack frame unwinders can be used for architectures\n\
2432 that support the DWARF unwinders. Enabling the DWARF unwinders for an\n\
2433 architecture that doesn't support them will have no effect."),
2435 show_dwarf_unwinders_enabled_p,
2437 &show_dwarf_cmdlist);
2440 selftests::register_test_foreach_arch ("execute_cfa_program",
2441 selftests::execute_cfa_program_test);