1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003-2013 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"
35 #include "gdb_assert.h"
38 #include "complaints.h"
39 #include "dwarf2-frame.h"
41 #include "dwarf2loc.h"
42 #include "exceptions.h"
43 #include "dwarf2-frame-tailcall.h"
47 /* Call Frame Information (CFI). */
49 /* Common Information Entry (CIE). */
53 /* Computation Unit for this CIE. */
54 struct comp_unit *unit;
56 /* Offset into the .debug_frame section where this CIE was found.
57 Used to identify this CIE. */
60 /* Constant that is factored out of all advance location
62 ULONGEST code_alignment_factor;
64 /* Constants that is factored out of all offset instructions. */
65 LONGEST data_alignment_factor;
67 /* Return address column. */
68 ULONGEST return_address_register;
70 /* Instruction sequence to initialize a register set. */
71 const gdb_byte *initial_instructions;
74 /* Saved augmentation, in case it's needed later. */
77 /* Encoding of addresses. */
80 /* Target address size in bytes. */
83 /* Target pointer size in bytes. */
86 /* True if a 'z' augmentation existed. */
87 unsigned char saw_z_augmentation;
89 /* True if an 'S' augmentation existed. */
90 unsigned char signal_frame;
92 /* The version recorded in the CIE. */
93 unsigned char version;
95 /* The segment size. */
96 unsigned char segment_size;
99 struct dwarf2_cie_table
102 struct dwarf2_cie **entries;
105 /* Frame Description Entry (FDE). */
109 /* CIE for this FDE. */
110 struct dwarf2_cie *cie;
112 /* First location associated with this FDE. */
113 CORE_ADDR initial_location;
115 /* Number of bytes of program instructions described by this FDE. */
116 CORE_ADDR address_range;
118 /* Instruction sequence. */
119 const gdb_byte *instructions;
122 /* True if this FDE is read from a .eh_frame instead of a .debug_frame
124 unsigned char eh_frame_p;
127 struct dwarf2_fde_table
130 struct dwarf2_fde **entries;
133 /* A minimal decoding of DWARF2 compilation units. We only decode
134 what's needed to get to the call frame information. */
138 /* Keep the bfd convenient. */
141 struct objfile *objfile;
143 /* Pointer to the .debug_frame section loaded into memory. */
144 const gdb_byte *dwarf_frame_buffer;
146 /* Length of the loaded .debug_frame section. */
147 bfd_size_type dwarf_frame_size;
149 /* Pointer to the .debug_frame section. */
150 asection *dwarf_frame_section;
152 /* Base for DW_EH_PE_datarel encodings. */
155 /* Base for DW_EH_PE_textrel encodings. */
159 static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc,
160 CORE_ADDR *out_offset);
162 static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
165 static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
166 int ptr_len, const gdb_byte *buf,
167 unsigned int *bytes_read_ptr,
168 CORE_ADDR func_base);
171 /* Structure describing a frame state. */
173 struct dwarf2_frame_state
175 /* Each register save state can be described in terms of a CFA slot,
176 another register, or a location expression. */
177 struct dwarf2_frame_state_reg_info
179 struct dwarf2_frame_state_reg *reg;
189 const gdb_byte *cfa_exp;
191 /* Used to implement DW_CFA_remember_state. */
192 struct dwarf2_frame_state_reg_info *prev;
195 /* The PC described by the current frame state. */
198 /* Initial register set from the CIE.
199 Used to implement DW_CFA_restore. */
200 struct dwarf2_frame_state_reg_info initial;
202 /* The information we care about from the CIE. */
205 ULONGEST retaddr_column;
207 /* Flags for known producer quirks. */
209 /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
210 and DW_CFA_def_cfa_offset takes a factored offset. */
211 int armcc_cfa_offsets_sf;
213 /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
214 the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
215 int armcc_cfa_offsets_reversed;
218 /* Store the length the expression for the CFA in the `cfa_reg' field,
219 which is unused in that case. */
220 #define cfa_exp_len cfa_reg
222 /* Assert that the register set RS is large enough to store gdbarch_num_regs
223 columns. If necessary, enlarge the register set. */
226 dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
229 size_t size = sizeof (struct dwarf2_frame_state_reg);
231 if (num_regs <= rs->num_regs)
234 rs->reg = (struct dwarf2_frame_state_reg *)
235 xrealloc (rs->reg, num_regs * size);
237 /* Initialize newly allocated registers. */
238 memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size);
239 rs->num_regs = num_regs;
242 /* Copy the register columns in register set RS into newly allocated
243 memory and return a pointer to this newly created copy. */
245 static struct dwarf2_frame_state_reg *
246 dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs)
248 size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg);
249 struct dwarf2_frame_state_reg *reg;
251 reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
252 memcpy (reg, rs->reg, size);
257 /* Release the memory allocated to register set RS. */
260 dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs)
264 dwarf2_frame_state_free_regs (rs->prev);
271 /* Release the memory allocated to the frame state FS. */
274 dwarf2_frame_state_free (void *p)
276 struct dwarf2_frame_state *fs = p;
278 dwarf2_frame_state_free_regs (fs->initial.prev);
279 dwarf2_frame_state_free_regs (fs->regs.prev);
280 xfree (fs->initial.reg);
281 xfree (fs->regs.reg);
286 /* Helper functions for execute_stack_op. */
289 read_addr_from_reg (void *baton, int reg)
291 struct frame_info *this_frame = (struct frame_info *) baton;
292 struct gdbarch *gdbarch = get_frame_arch (this_frame);
296 regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
298 buf = alloca (register_size (gdbarch, regnum));
299 get_frame_register (this_frame, regnum, buf);
301 return unpack_pointer (register_type (gdbarch, regnum), buf);
304 /* Implement struct dwarf_expr_context_funcs' "get_reg_value" callback. */
306 static struct value *
307 get_reg_value (void *baton, struct type *type, int reg)
309 struct frame_info *this_frame = (struct frame_info *) baton;
310 struct gdbarch *gdbarch = get_frame_arch (this_frame);
311 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
313 return value_from_register (type, regnum, this_frame);
317 read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
319 read_memory (addr, buf, len);
322 /* Execute the required actions for both the DW_CFA_restore and
323 DW_CFA_restore_extended instructions. */
325 dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
326 struct dwarf2_frame_state *fs, int eh_frame_p)
330 gdb_assert (fs->initial.reg);
331 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
332 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
334 /* Check if this register was explicitly initialized in the
335 CIE initial instructions. If not, default the rule to
337 if (reg < fs->initial.num_regs)
338 fs->regs.reg[reg] = fs->initial.reg[reg];
340 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
342 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
343 complaint (&symfile_complaints, _("\
344 incomplete CFI data; DW_CFA_restore unspecified\n\
345 register %s (#%d) at %s"),
346 gdbarch_register_name
347 (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
348 gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
349 paddress (gdbarch, fs->pc));
352 /* Virtual method table for execute_stack_op below. */
354 static const struct dwarf_expr_context_funcs dwarf2_frame_ctx_funcs =
359 ctx_no_get_frame_base,
360 ctx_no_get_frame_cfa,
362 ctx_no_get_tls_address,
364 ctx_no_get_base_type,
365 ctx_no_push_dwarf_reg_entry_value,
366 ctx_no_get_addr_index
370 execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
371 CORE_ADDR offset, struct frame_info *this_frame,
372 CORE_ADDR initial, int initial_in_stack_memory)
374 struct dwarf_expr_context *ctx;
376 struct cleanup *old_chain;
378 ctx = new_dwarf_expr_context ();
379 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
380 make_cleanup_value_free_to_mark (value_mark ());
382 ctx->gdbarch = get_frame_arch (this_frame);
383 ctx->addr_size = addr_size;
384 ctx->ref_addr_size = -1;
385 ctx->offset = offset;
386 ctx->baton = this_frame;
387 ctx->funcs = &dwarf2_frame_ctx_funcs;
389 dwarf_expr_push_address (ctx, initial, initial_in_stack_memory);
390 dwarf_expr_eval (ctx, exp, len);
392 if (ctx->location == DWARF_VALUE_MEMORY)
393 result = dwarf_expr_fetch_address (ctx, 0);
394 else if (ctx->location == DWARF_VALUE_REGISTER)
395 result = read_addr_from_reg (this_frame,
396 value_as_long (dwarf_expr_fetch (ctx, 0)));
399 /* This is actually invalid DWARF, but if we ever do run across
400 it somehow, we might as well support it. So, instead, report
401 it as unimplemented. */
403 Not implemented: computing unwound register using explicit value operator"));
406 do_cleanups (old_chain);
412 /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
413 PC. Modify FS state accordingly. Return current INSN_PTR where the
414 execution has stopped, one can resume it on the next call. */
416 static const gdb_byte *
417 execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
418 const gdb_byte *insn_end, struct gdbarch *gdbarch,
419 CORE_ADDR pc, struct dwarf2_frame_state *fs)
421 int eh_frame_p = fde->eh_frame_p;
422 unsigned int bytes_read;
423 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
425 while (insn_ptr < insn_end && fs->pc <= pc)
427 gdb_byte insn = *insn_ptr++;
431 if ((insn & 0xc0) == DW_CFA_advance_loc)
432 fs->pc += (insn & 0x3f) * fs->code_align;
433 else if ((insn & 0xc0) == DW_CFA_offset)
436 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
437 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
438 offset = utmp * fs->data_align;
439 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
440 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
441 fs->regs.reg[reg].loc.offset = offset;
443 else if ((insn & 0xc0) == DW_CFA_restore)
446 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
453 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
454 fde->cie->ptr_size, insn_ptr,
455 &bytes_read, fde->initial_location);
456 /* Apply the objfile offset for relocatable objects. */
457 fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
458 SECT_OFF_TEXT (fde->cie->unit->objfile));
459 insn_ptr += bytes_read;
462 case DW_CFA_advance_loc1:
463 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
464 fs->pc += utmp * fs->code_align;
467 case DW_CFA_advance_loc2:
468 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
469 fs->pc += utmp * fs->code_align;
472 case DW_CFA_advance_loc4:
473 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
474 fs->pc += utmp * fs->code_align;
478 case DW_CFA_offset_extended:
479 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
480 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
481 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
482 offset = utmp * fs->data_align;
483 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
484 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
485 fs->regs.reg[reg].loc.offset = offset;
488 case DW_CFA_restore_extended:
489 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
490 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
493 case DW_CFA_undefined:
494 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
495 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
496 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
497 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
500 case DW_CFA_same_value:
501 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
502 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
503 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
504 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
507 case DW_CFA_register:
508 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
509 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
510 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
511 utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
512 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
513 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
514 fs->regs.reg[reg].loc.reg = utmp;
517 case DW_CFA_remember_state:
519 struct dwarf2_frame_state_reg_info *new_rs;
521 new_rs = XMALLOC (struct dwarf2_frame_state_reg_info);
523 fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
524 fs->regs.prev = new_rs;
528 case DW_CFA_restore_state:
530 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
534 complaint (&symfile_complaints, _("\
535 bad CFI data; mismatched DW_CFA_restore_state at %s"),
536 paddress (gdbarch, fs->pc));
540 xfree (fs->regs.reg);
548 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
549 fs->regs.cfa_reg = reg;
550 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
552 if (fs->armcc_cfa_offsets_sf)
553 utmp *= fs->data_align;
555 fs->regs.cfa_offset = utmp;
556 fs->regs.cfa_how = CFA_REG_OFFSET;
559 case DW_CFA_def_cfa_register:
560 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
561 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
563 fs->regs.cfa_how = CFA_REG_OFFSET;
566 case DW_CFA_def_cfa_offset:
567 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
569 if (fs->armcc_cfa_offsets_sf)
570 utmp *= fs->data_align;
572 fs->regs.cfa_offset = utmp;
573 /* cfa_how deliberately not set. */
579 case DW_CFA_def_cfa_expression:
580 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
581 fs->regs.cfa_exp_len = utmp;
582 fs->regs.cfa_exp = insn_ptr;
583 fs->regs.cfa_how = CFA_EXP;
584 insn_ptr += fs->regs.cfa_exp_len;
587 case DW_CFA_expression:
588 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
589 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
590 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
591 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
592 fs->regs.reg[reg].loc.exp = insn_ptr;
593 fs->regs.reg[reg].exp_len = utmp;
594 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
598 case DW_CFA_offset_extended_sf:
599 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
600 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
601 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
602 offset *= fs->data_align;
603 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
604 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
605 fs->regs.reg[reg].loc.offset = offset;
608 case DW_CFA_val_offset:
609 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
610 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
611 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
612 offset = utmp * fs->data_align;
613 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
614 fs->regs.reg[reg].loc.offset = offset;
617 case DW_CFA_val_offset_sf:
618 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
619 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
620 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
621 offset *= fs->data_align;
622 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
623 fs->regs.reg[reg].loc.offset = offset;
626 case DW_CFA_val_expression:
627 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
628 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
629 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
630 fs->regs.reg[reg].loc.exp = insn_ptr;
631 fs->regs.reg[reg].exp_len = utmp;
632 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
636 case DW_CFA_def_cfa_sf:
637 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
638 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, reg,
640 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
641 fs->regs.cfa_offset = offset * fs->data_align;
642 fs->regs.cfa_how = CFA_REG_OFFSET;
645 case DW_CFA_def_cfa_offset_sf:
646 insn_ptr = safe_read_sleb128 (insn_ptr, insn_end, &offset);
647 fs->regs.cfa_offset = offset * fs->data_align;
648 /* cfa_how deliberately not set. */
651 case DW_CFA_GNU_window_save:
652 /* This is SPARC-specific code, and contains hard-coded
653 constants for the register numbering scheme used by
654 GCC. Rather than having a architecture-specific
655 operation that's only ever used by a single
656 architecture, we provide the implementation here.
657 Incidentally that's what GCC does too in its
660 int size = register_size (gdbarch, 0);
662 dwarf2_frame_state_alloc_regs (&fs->regs, 32);
663 for (reg = 8; reg < 16; reg++)
665 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
666 fs->regs.reg[reg].loc.reg = reg + 16;
668 for (reg = 16; reg < 32; reg++)
670 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
671 fs->regs.reg[reg].loc.offset = (reg - 16) * size;
676 case DW_CFA_GNU_args_size:
678 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
681 case DW_CFA_GNU_negative_offset_extended:
682 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, ®);
683 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
684 insn_ptr = safe_read_uleb128 (insn_ptr, insn_end, &utmp);
685 offset = utmp * fs->data_align;
686 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
687 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
688 fs->regs.reg[reg].loc.offset = -offset;
692 internal_error (__FILE__, __LINE__,
693 _("Unknown CFI encountered."));
698 if (fs->initial.reg == NULL)
700 /* Don't allow remember/restore between CIE and FDE programs. */
701 dwarf2_frame_state_free_regs (fs->regs.prev);
702 fs->regs.prev = NULL;
709 /* Architecture-specific operations. */
711 /* Per-architecture data key. */
712 static struct gdbarch_data *dwarf2_frame_data;
714 struct dwarf2_frame_ops
716 /* Pre-initialize the register state REG for register REGNUM. */
717 void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
718 struct frame_info *);
720 /* Check whether the THIS_FRAME is a signal trampoline. */
721 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
723 /* Convert .eh_frame register number to DWARF register number, or
724 adjust .debug_frame register number. */
725 int (*adjust_regnum) (struct gdbarch *, int, int);
728 /* Default architecture-specific register state initialization
732 dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
733 struct dwarf2_frame_state_reg *reg,
734 struct frame_info *this_frame)
736 /* If we have a register that acts as a program counter, mark it as
737 a destination for the return address. If we have a register that
738 serves as the stack pointer, arrange for it to be filled with the
739 call frame address (CFA). The other registers are marked as
742 We copy the return address to the program counter, since many
743 parts in GDB assume that it is possible to get the return address
744 by unwinding the program counter register. However, on ISA's
745 with a dedicated return address register, the CFI usually only
746 contains information to unwind that return address register.
748 The reason we're treating the stack pointer special here is
749 because in many cases GCC doesn't emit CFI for the stack pointer
750 and implicitly assumes that it is equal to the CFA. This makes
751 some sense since the DWARF specification (version 3, draft 8,
754 "Typically, the CFA is defined to be the value of the stack
755 pointer at the call site in the previous frame (which may be
756 different from its value on entry to the current frame)."
758 However, this isn't true for all platforms supported by GCC
759 (e.g. IBM S/390 and zSeries). Those architectures should provide
760 their own architecture-specific initialization function. */
762 if (regnum == gdbarch_pc_regnum (gdbarch))
763 reg->how = DWARF2_FRAME_REG_RA;
764 else if (regnum == gdbarch_sp_regnum (gdbarch))
765 reg->how = DWARF2_FRAME_REG_CFA;
768 /* Return a default for the architecture-specific operations. */
771 dwarf2_frame_init (struct obstack *obstack)
773 struct dwarf2_frame_ops *ops;
775 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
776 ops->init_reg = dwarf2_frame_default_init_reg;
780 /* Set the architecture-specific register state initialization
781 function for GDBARCH to INIT_REG. */
784 dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
785 void (*init_reg) (struct gdbarch *, int,
786 struct dwarf2_frame_state_reg *,
787 struct frame_info *))
789 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
791 ops->init_reg = init_reg;
794 /* Pre-initialize the register state REG for register REGNUM. */
797 dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
798 struct dwarf2_frame_state_reg *reg,
799 struct frame_info *this_frame)
801 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
803 ops->init_reg (gdbarch, regnum, reg, this_frame);
806 /* Set the architecture-specific signal trampoline recognition
807 function for GDBARCH to SIGNAL_FRAME_P. */
810 dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
811 int (*signal_frame_p) (struct gdbarch *,
812 struct frame_info *))
814 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
816 ops->signal_frame_p = signal_frame_p;
819 /* Query the architecture-specific signal frame recognizer for
823 dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
824 struct frame_info *this_frame)
826 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
828 if (ops->signal_frame_p == NULL)
830 return ops->signal_frame_p (gdbarch, this_frame);
833 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
837 dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
838 int (*adjust_regnum) (struct gdbarch *,
841 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
843 ops->adjust_regnum = adjust_regnum;
846 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
850 dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch,
851 int regnum, int eh_frame_p)
853 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
855 if (ops->adjust_regnum == NULL)
857 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
861 dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
862 struct dwarf2_fde *fde)
866 s = find_pc_symtab (fs->pc);
870 if (producer_is_realview (s->producer))
872 if (fde->cie->version == 1)
873 fs->armcc_cfa_offsets_sf = 1;
875 if (fde->cie->version == 1)
876 fs->armcc_cfa_offsets_reversed = 1;
878 /* The reversed offset problem is present in some compilers
879 using DWARF3, but it was eventually fixed. Check the ARM
880 defined augmentations, which are in the format "armcc" followed
881 by a list of one-character options. The "+" option means
882 this problem is fixed (no quirk needed). If the armcc
883 augmentation is missing, the quirk is needed. */
884 if (fde->cie->version == 3
885 && (strncmp (fde->cie->augmentation, "armcc", 5) != 0
886 || strchr (fde->cie->augmentation + 5, '+') == NULL))
887 fs->armcc_cfa_offsets_reversed = 1;
895 dwarf2_compile_cfa_to_ax (struct agent_expr *expr, struct axs_value *loc,
896 struct gdbarch *gdbarch,
898 struct dwarf2_per_cu_data *data)
900 struct dwarf2_fde *fde;
901 CORE_ADDR text_offset;
902 struct dwarf2_frame_state fs;
905 memset (&fs, 0, sizeof (struct dwarf2_frame_state));
909 /* Find the correct FDE. */
910 fde = dwarf2_frame_find_fde (&fs.pc, &text_offset);
912 error (_("Could not compute CFA; needed to translate this expression"));
914 /* Extract any interesting information from the CIE. */
915 fs.data_align = fde->cie->data_alignment_factor;
916 fs.code_align = fde->cie->code_alignment_factor;
917 fs.retaddr_column = fde->cie->return_address_register;
918 addr_size = fde->cie->addr_size;
920 /* Check for "quirks" - known bugs in producers. */
921 dwarf2_frame_find_quirks (&fs, fde);
923 /* First decode all the insns in the CIE. */
924 execute_cfa_program (fde, fde->cie->initial_instructions,
925 fde->cie->end, gdbarch, pc, &fs);
927 /* Save the initialized register set. */
928 fs.initial = fs.regs;
929 fs.initial.reg = dwarf2_frame_state_copy_regs (&fs.regs);
931 /* Then decode the insns in the FDE up to our target PC. */
932 execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);
934 /* Calculate the CFA. */
935 switch (fs.regs.cfa_how)
939 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, fs.regs.cfa_reg);
942 error (_("Unable to access DWARF register number %d"),
943 (int) fs.regs.cfa_reg); /* FIXME */
944 ax_reg (expr, regnum);
946 if (fs.regs.cfa_offset != 0)
948 if (fs.armcc_cfa_offsets_reversed)
949 ax_const_l (expr, -fs.regs.cfa_offset);
951 ax_const_l (expr, fs.regs.cfa_offset);
952 ax_simple (expr, aop_add);
958 ax_const_l (expr, text_offset);
959 dwarf2_compile_expr_to_ax (expr, loc, gdbarch, addr_size,
961 fs.regs.cfa_exp + fs.regs.cfa_exp_len,
966 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
971 struct dwarf2_frame_cache
973 /* DWARF Call Frame Address. */
976 /* Set if the return address column was marked as unavailable
977 (required non-collected memory or registers to compute). */
978 int unavailable_retaddr;
980 /* Set if the return address column was marked as undefined. */
981 int undefined_retaddr;
983 /* Saved registers, indexed by GDB register number, not by DWARF
985 struct dwarf2_frame_state_reg *reg;
987 /* Return address register. */
988 struct dwarf2_frame_state_reg retaddr_reg;
990 /* Target address size in bytes. */
993 /* The .text offset. */
994 CORE_ADDR text_offset;
996 /* True if we already checked whether this frame is the bottom frame
997 of a virtual tail call frame chain. */
998 int checked_tailcall_bottom;
1000 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
1001 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
1002 involved. Non-bottom frames of a virtual tail call frames chain use
1003 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
1005 void *tailcall_cache;
1007 /* The number of bytes to subtract from TAILCALL_FRAME frames frame
1008 base to get the SP, to simulate the return address pushed on the
1010 LONGEST entry_cfa_sp_offset;
1011 int entry_cfa_sp_offset_p;
1014 /* A cleanup that sets a pointer to NULL. */
1017 clear_pointer_cleanup (void *arg)
1024 static struct dwarf2_frame_cache *
1025 dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
1027 struct cleanup *reset_cache_cleanup, *old_chain;
1028 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1029 const int num_regs = gdbarch_num_regs (gdbarch)
1030 + gdbarch_num_pseudo_regs (gdbarch);
1031 struct dwarf2_frame_cache *cache;
1032 struct dwarf2_frame_state *fs;
1033 struct dwarf2_fde *fde;
1034 volatile struct gdb_exception ex;
1036 const gdb_byte *instr;
1041 /* Allocate a new cache. */
1042 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
1043 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
1044 *this_cache = cache;
1045 reset_cache_cleanup = make_cleanup (clear_pointer_cleanup, this_cache);
1047 /* Allocate and initialize the frame state. */
1048 fs = XZALLOC (struct dwarf2_frame_state);
1049 old_chain = make_cleanup (dwarf2_frame_state_free, fs);
1053 Note that if the next frame is never supposed to return (i.e. a call
1054 to abort), the compiler might optimize away the instruction at
1055 its return address. As a result the return address will
1056 point at some random instruction, and the CFI for that
1057 instruction is probably worthless to us. GCC's unwinder solves
1058 this problem by substracting 1 from the return address to get an
1059 address in the middle of a presumed call instruction (or the
1060 instruction in the associated delay slot). This should only be
1061 done for "normal" frames and not for resume-type frames (signal
1062 handlers, sentinel frames, dummy frames). The function
1063 get_frame_address_in_block does just this. It's not clear how
1064 reliable the method is though; there is the potential for the
1065 register state pre-call being different to that on return. */
1066 fs->pc = get_frame_address_in_block (this_frame);
1068 /* Find the correct FDE. */
1069 fde = dwarf2_frame_find_fde (&fs->pc, &cache->text_offset);
1070 gdb_assert (fde != NULL);
1072 /* Extract any interesting information from the CIE. */
1073 fs->data_align = fde->cie->data_alignment_factor;
1074 fs->code_align = fde->cie->code_alignment_factor;
1075 fs->retaddr_column = fde->cie->return_address_register;
1076 cache->addr_size = fde->cie->addr_size;
1078 /* Check for "quirks" - known bugs in producers. */
1079 dwarf2_frame_find_quirks (fs, fde);
1081 /* First decode all the insns in the CIE. */
1082 execute_cfa_program (fde, fde->cie->initial_instructions,
1083 fde->cie->end, gdbarch,
1084 get_frame_address_in_block (this_frame), fs);
1086 /* Save the initialized register set. */
1087 fs->initial = fs->regs;
1088 fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
1090 if (get_frame_func_if_available (this_frame, &entry_pc))
1092 /* Decode the insns in the FDE up to the entry PC. */
1093 instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
1096 if (fs->regs.cfa_how == CFA_REG_OFFSET
1097 && (gdbarch_dwarf2_reg_to_regnum (gdbarch, fs->regs.cfa_reg)
1098 == gdbarch_sp_regnum (gdbarch)))
1100 cache->entry_cfa_sp_offset = fs->regs.cfa_offset;
1101 cache->entry_cfa_sp_offset_p = 1;
1105 instr = fde->instructions;
1107 /* Then decode the insns in the FDE up to our target PC. */
1108 execute_cfa_program (fde, instr, fde->end, gdbarch,
1109 get_frame_address_in_block (this_frame), fs);
1111 TRY_CATCH (ex, RETURN_MASK_ERROR)
1113 /* Calculate the CFA. */
1114 switch (fs->regs.cfa_how)
1116 case CFA_REG_OFFSET:
1117 cache->cfa = read_addr_from_reg (this_frame, fs->regs.cfa_reg);
1118 if (fs->armcc_cfa_offsets_reversed)
1119 cache->cfa -= fs->regs.cfa_offset;
1121 cache->cfa += fs->regs.cfa_offset;
1126 execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
1127 cache->addr_size, cache->text_offset,
1132 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
1137 if (ex.error == NOT_AVAILABLE_ERROR)
1139 cache->unavailable_retaddr = 1;
1140 do_cleanups (old_chain);
1141 discard_cleanups (reset_cache_cleanup);
1145 throw_exception (ex);
1148 /* Initialize the register state. */
1152 for (regnum = 0; regnum < num_regs; regnum++)
1153 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
1156 /* Go through the DWARF2 CFI generated table and save its register
1157 location information in the cache. Note that we don't skip the
1158 return address column; it's perfectly all right for it to
1159 correspond to a real register. If it doesn't correspond to a
1160 real register, or if we shouldn't treat it as such,
1161 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
1162 the range [0, gdbarch_num_regs). */
1164 int column; /* CFI speak for "register number". */
1166 for (column = 0; column < fs->regs.num_regs; column++)
1168 /* Use the GDB register number as the destination index. */
1169 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
1171 /* If there's no corresponding GDB register, ignore it. */
1172 if (regnum < 0 || regnum >= num_regs)
1175 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1176 of all debug info registers. If it doesn't, complain (but
1177 not too loudly). It turns out that GCC assumes that an
1178 unspecified register implies "same value" when CFI (draft
1179 7) specifies nothing at all. Such a register could equally
1180 be interpreted as "undefined". Also note that this check
1181 isn't sufficient; it only checks that all registers in the
1182 range [0 .. max column] are specified, and won't detect
1183 problems when a debug info register falls outside of the
1184 table. We need a way of iterating through all the valid
1185 DWARF2 register numbers. */
1186 if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1188 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1189 complaint (&symfile_complaints, _("\
1190 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1191 gdbarch_register_name (gdbarch, regnum),
1192 paddress (gdbarch, fs->pc));
1195 cache->reg[regnum] = fs->regs.reg[column];
1199 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1200 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1204 for (regnum = 0; regnum < num_regs; regnum++)
1206 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1207 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1209 struct dwarf2_frame_state_reg *retaddr_reg =
1210 &fs->regs.reg[fs->retaddr_column];
1212 /* It seems rather bizarre to specify an "empty" column as
1213 the return adress column. However, this is exactly
1214 what GCC does on some targets. It turns out that GCC
1215 assumes that the return address can be found in the
1216 register corresponding to the return address column.
1217 Incidentally, that's how we should treat a return
1218 address column specifying "same value" too. */
1219 if (fs->retaddr_column < fs->regs.num_regs
1220 && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
1221 && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
1223 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1224 cache->reg[regnum] = *retaddr_reg;
1226 cache->retaddr_reg = *retaddr_reg;
1230 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1232 cache->reg[regnum].loc.reg = fs->retaddr_column;
1233 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1237 cache->retaddr_reg.loc.reg = fs->retaddr_column;
1238 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1245 if (fs->retaddr_column < fs->regs.num_regs
1246 && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1247 cache->undefined_retaddr = 1;
1249 do_cleanups (old_chain);
1250 discard_cleanups (reset_cache_cleanup);
1254 static enum unwind_stop_reason
1255 dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame,
1258 struct dwarf2_frame_cache *cache
1259 = dwarf2_frame_cache (this_frame, this_cache);
1261 if (cache->unavailable_retaddr)
1262 return UNWIND_UNAVAILABLE;
1264 if (cache->undefined_retaddr)
1265 return UNWIND_OUTERMOST;
1267 return UNWIND_NO_REASON;
1271 dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1272 struct frame_id *this_id)
1274 struct dwarf2_frame_cache *cache =
1275 dwarf2_frame_cache (this_frame, this_cache);
1277 if (cache->unavailable_retaddr)
1280 if (cache->undefined_retaddr)
1283 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1286 static struct value *
1287 dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1290 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1291 struct dwarf2_frame_cache *cache =
1292 dwarf2_frame_cache (this_frame, this_cache);
1296 /* Check whether THIS_FRAME is the bottom frame of a virtual tail
1297 call frame chain. */
1298 if (!cache->checked_tailcall_bottom)
1300 cache->checked_tailcall_bottom = 1;
1301 dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache,
1302 (cache->entry_cfa_sp_offset_p
1303 ? &cache->entry_cfa_sp_offset : NULL));
1306 /* Non-bottom frames of a virtual tail call frames chain use
1307 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1308 them. If dwarf2_tailcall_prev_register_first does not have specific value
1309 unwind the register, tail call frames are assumed to have the register set
1310 of the top caller. */
1311 if (cache->tailcall_cache)
1315 val = dwarf2_tailcall_prev_register_first (this_frame,
1316 &cache->tailcall_cache,
1322 switch (cache->reg[regnum].how)
1324 case DWARF2_FRAME_REG_UNDEFINED:
1325 /* If CFI explicitly specified that the value isn't defined,
1326 mark it as optimized away; the value isn't available. */
1327 return frame_unwind_got_optimized (this_frame, regnum);
1329 case DWARF2_FRAME_REG_SAVED_OFFSET:
1330 addr = cache->cfa + cache->reg[regnum].loc.offset;
1331 return frame_unwind_got_memory (this_frame, regnum, addr);
1333 case DWARF2_FRAME_REG_SAVED_REG:
1335 = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
1336 return frame_unwind_got_register (this_frame, regnum, realnum);
1338 case DWARF2_FRAME_REG_SAVED_EXP:
1339 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1340 cache->reg[regnum].exp_len,
1341 cache->addr_size, cache->text_offset,
1342 this_frame, cache->cfa, 1);
1343 return frame_unwind_got_memory (this_frame, regnum, addr);
1345 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1346 addr = cache->cfa + cache->reg[regnum].loc.offset;
1347 return frame_unwind_got_constant (this_frame, regnum, addr);
1349 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1350 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1351 cache->reg[regnum].exp_len,
1352 cache->addr_size, cache->text_offset,
1353 this_frame, cache->cfa, 1);
1354 return frame_unwind_got_constant (this_frame, regnum, addr);
1356 case DWARF2_FRAME_REG_UNSPECIFIED:
1357 /* GCC, in its infinite wisdom decided to not provide unwind
1358 information for registers that are "same value". Since
1359 DWARF2 (3 draft 7) doesn't define such behavior, said
1360 registers are actually undefined (which is different to CFI
1361 "undefined"). Code above issues a complaint about this.
1362 Here just fudge the books, assume GCC, and that the value is
1363 more inner on the stack. */
1364 return frame_unwind_got_register (this_frame, regnum, regnum);
1366 case DWARF2_FRAME_REG_SAME_VALUE:
1367 return frame_unwind_got_register (this_frame, regnum, regnum);
1369 case DWARF2_FRAME_REG_CFA:
1370 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1372 case DWARF2_FRAME_REG_CFA_OFFSET:
1373 addr = cache->cfa + cache->reg[regnum].loc.offset;
1374 return frame_unwind_got_address (this_frame, regnum, addr);
1376 case DWARF2_FRAME_REG_RA_OFFSET:
1377 addr = cache->reg[regnum].loc.offset;
1378 regnum = gdbarch_dwarf2_reg_to_regnum
1379 (gdbarch, cache->retaddr_reg.loc.reg);
1380 addr += get_frame_register_unsigned (this_frame, regnum);
1381 return frame_unwind_got_address (this_frame, regnum, addr);
1383 case DWARF2_FRAME_REG_FN:
1384 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1387 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1391 /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1392 call frames chain. */
1395 dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache)
1397 struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache);
1399 if (cache->tailcall_cache)
1400 dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache);
1404 dwarf2_frame_sniffer (const struct frame_unwind *self,
1405 struct frame_info *this_frame, void **this_cache)
1407 /* Grab an address that is guarenteed to reside somewhere within the
1408 function. get_frame_pc(), with a no-return next function, can
1409 end up returning something past the end of this function's body.
1410 If the frame we're sniffing for is a signal frame whose start
1411 address is placed on the stack by the OS, its FDE must
1412 extend one byte before its start address or we could potentially
1413 select the FDE of the previous function. */
1414 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1415 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL);
1420 /* On some targets, signal trampolines may have unwind information.
1421 We need to recognize them so that we set the frame type
1424 if (fde->cie->signal_frame
1425 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1427 return self->type == SIGTRAMP_FRAME;
1429 if (self->type != NORMAL_FRAME)
1435 static const struct frame_unwind dwarf2_frame_unwind =
1438 dwarf2_frame_unwind_stop_reason,
1439 dwarf2_frame_this_id,
1440 dwarf2_frame_prev_register,
1442 dwarf2_frame_sniffer,
1443 dwarf2_frame_dealloc_cache
1446 static const struct frame_unwind dwarf2_signal_frame_unwind =
1449 dwarf2_frame_unwind_stop_reason,
1450 dwarf2_frame_this_id,
1451 dwarf2_frame_prev_register,
1453 dwarf2_frame_sniffer,
1455 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1459 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1462 dwarf2_append_unwinders (struct gdbarch *gdbarch)
1464 /* TAILCALL_FRAME must be first to find the record by
1465 dwarf2_tailcall_sniffer_first. */
1466 frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind);
1468 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1469 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1473 /* There is no explicitly defined relationship between the CFA and the
1474 location of frame's local variables and arguments/parameters.
1475 Therefore, frame base methods on this page should probably only be
1476 used as a last resort, just to avoid printing total garbage as a
1477 response to the "info frame" command. */
1480 dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1482 struct dwarf2_frame_cache *cache =
1483 dwarf2_frame_cache (this_frame, this_cache);
1488 static const struct frame_base dwarf2_frame_base =
1490 &dwarf2_frame_unwind,
1491 dwarf2_frame_base_address,
1492 dwarf2_frame_base_address,
1493 dwarf2_frame_base_address
1496 const struct frame_base *
1497 dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1499 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1501 if (dwarf2_frame_find_fde (&block_addr, NULL))
1502 return &dwarf2_frame_base;
1507 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1508 the DWARF unwinder. This is used to implement
1509 DW_OP_call_frame_cfa. */
1512 dwarf2_frame_cfa (struct frame_info *this_frame)
1514 while (get_frame_type (this_frame) == INLINE_FRAME)
1515 this_frame = get_prev_frame (this_frame);
1516 /* This restriction could be lifted if other unwinders are known to
1517 compute the frame base in a way compatible with the DWARF
1519 if (!frame_unwinder_is (this_frame, &dwarf2_frame_unwind)
1520 && !frame_unwinder_is (this_frame, &dwarf2_tailcall_frame_unwind))
1521 error (_("can't compute CFA for this frame"));
1522 if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE)
1523 throw_error (NOT_AVAILABLE_ERROR,
1524 _("can't compute CFA for this frame: "
1525 "required registers or memory are unavailable"));
1526 return get_frame_base (this_frame);
1529 const struct objfile_data *dwarf2_frame_objfile_data;
1532 read_1_byte (bfd *abfd, const gdb_byte *buf)
1534 return bfd_get_8 (abfd, buf);
1538 read_4_bytes (bfd *abfd, const gdb_byte *buf)
1540 return bfd_get_32 (abfd, buf);
1544 read_8_bytes (bfd *abfd, const gdb_byte *buf)
1546 return bfd_get_64 (abfd, buf);
1550 read_initial_length (bfd *abfd, const gdb_byte *buf,
1551 unsigned int *bytes_read_ptr)
1555 result = bfd_get_32 (abfd, buf);
1556 if (result == 0xffffffff)
1558 result = bfd_get_64 (abfd, buf + 4);
1559 *bytes_read_ptr = 12;
1562 *bytes_read_ptr = 4;
1568 /* Pointer encoding helper functions. */
1570 /* GCC supports exception handling based on DWARF2 CFI. However, for
1571 technical reasons, it encodes addresses in its FDE's in a different
1572 way. Several "pointer encodings" are supported. The encoding
1573 that's used for a particular FDE is determined by the 'R'
1574 augmentation in the associated CIE. The argument of this
1575 augmentation is a single byte.
1577 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1578 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1579 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1580 address should be interpreted (absolute, relative to the current
1581 position in the FDE, ...). Bit 7, indicates that the address
1582 should be dereferenced. */
1585 encoding_for_size (unsigned int size)
1590 return DW_EH_PE_udata2;
1592 return DW_EH_PE_udata4;
1594 return DW_EH_PE_udata8;
1596 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1601 read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
1602 int ptr_len, const gdb_byte *buf,
1603 unsigned int *bytes_read_ptr,
1604 CORE_ADDR func_base)
1609 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1611 if (encoding & DW_EH_PE_indirect)
1612 internal_error (__FILE__, __LINE__,
1613 _("Unsupported encoding: DW_EH_PE_indirect"));
1615 *bytes_read_ptr = 0;
1617 switch (encoding & 0x70)
1619 case DW_EH_PE_absptr:
1622 case DW_EH_PE_pcrel:
1623 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1624 base += (buf - unit->dwarf_frame_buffer);
1626 case DW_EH_PE_datarel:
1629 case DW_EH_PE_textrel:
1632 case DW_EH_PE_funcrel:
1635 case DW_EH_PE_aligned:
1637 offset = buf - unit->dwarf_frame_buffer;
1638 if ((offset % ptr_len) != 0)
1640 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1641 buf += *bytes_read_ptr;
1645 internal_error (__FILE__, __LINE__,
1646 _("Invalid or unsupported encoding"));
1649 if ((encoding & 0x07) == 0x00)
1651 encoding |= encoding_for_size (ptr_len);
1652 if (bfd_get_sign_extend_vma (unit->abfd))
1653 encoding |= DW_EH_PE_signed;
1656 switch (encoding & 0x0f)
1658 case DW_EH_PE_uleb128:
1661 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1663 *bytes_read_ptr += safe_read_uleb128 (buf, end_buf, &value) - buf;
1664 return base + value;
1666 case DW_EH_PE_udata2:
1667 *bytes_read_ptr += 2;
1668 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1669 case DW_EH_PE_udata4:
1670 *bytes_read_ptr += 4;
1671 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1672 case DW_EH_PE_udata8:
1673 *bytes_read_ptr += 8;
1674 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1675 case DW_EH_PE_sleb128:
1678 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1680 *bytes_read_ptr += safe_read_sleb128 (buf, end_buf, &value) - buf;
1681 return base + value;
1683 case DW_EH_PE_sdata2:
1684 *bytes_read_ptr += 2;
1685 return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
1686 case DW_EH_PE_sdata4:
1687 *bytes_read_ptr += 4;
1688 return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
1689 case DW_EH_PE_sdata8:
1690 *bytes_read_ptr += 8;
1691 return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
1693 internal_error (__FILE__, __LINE__,
1694 _("Invalid or unsupported encoding"));
1700 bsearch_cie_cmp (const void *key, const void *element)
1702 ULONGEST cie_pointer = *(ULONGEST *) key;
1703 struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;
1705 if (cie_pointer == cie->cie_pointer)
1708 return (cie_pointer < cie->cie_pointer) ? -1 : 1;
1711 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1712 static struct dwarf2_cie *
1713 find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
1715 struct dwarf2_cie **p_cie;
1717 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1718 bsearch be non-NULL. */
1719 if (cie_table->entries == NULL)
1721 gdb_assert (cie_table->num_entries == 0);
1725 p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1726 sizeof (cie_table->entries[0]), bsearch_cie_cmp);
1732 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1734 add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1736 const int n = cie_table->num_entries;
1739 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1741 cie_table->entries =
1742 xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0]));
1743 cie_table->entries[n] = cie;
1744 cie_table->num_entries = n + 1;
1748 bsearch_fde_cmp (const void *key, const void *element)
1750 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1751 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
1753 if (seek_pc < fde->initial_location)
1755 if (seek_pc < fde->initial_location + fde->address_range)
1760 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1761 inital location associated with it into *PC. */
1763 static struct dwarf2_fde *
1764 dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset)
1766 struct objfile *objfile;
1768 ALL_OBJFILES (objfile)
1770 struct dwarf2_fde_table *fde_table;
1771 struct dwarf2_fde **p_fde;
1775 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1776 if (fde_table == NULL)
1778 dwarf2_build_frame_info (objfile);
1779 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1781 gdb_assert (fde_table != NULL);
1783 if (fde_table->num_entries == 0)
1786 gdb_assert (objfile->section_offsets);
1787 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1789 gdb_assert (fde_table->num_entries > 0);
1790 if (*pc < offset + fde_table->entries[0]->initial_location)
1793 seek_pc = *pc - offset;
1794 p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1795 sizeof (fde_table->entries[0]), bsearch_fde_cmp);
1798 *pc = (*p_fde)->initial_location + offset;
1800 *out_offset = offset;
1807 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1809 add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1811 if (fde->address_range == 0)
1812 /* Discard useless FDEs. */
1815 fde_table->num_entries += 1;
1816 fde_table->entries =
1817 xrealloc (fde_table->entries,
1818 fde_table->num_entries * sizeof (fde_table->entries[0]));
1819 fde_table->entries[fde_table->num_entries - 1] = fde;
1822 #define DW64_CIE_ID 0xffffffffffffffffULL
1824 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1829 EH_CIE_TYPE_ID = 1 << 0,
1830 EH_FDE_TYPE_ID = 1 << 1,
1831 EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID
1834 static const gdb_byte *decode_frame_entry (struct comp_unit *unit,
1835 const gdb_byte *start,
1837 struct dwarf2_cie_table *cie_table,
1838 struct dwarf2_fde_table *fde_table,
1839 enum eh_frame_type entry_type);
1841 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1842 Return NULL if invalid input, otherwise the next byte to be processed. */
1844 static const gdb_byte *
1845 decode_frame_entry_1 (struct comp_unit *unit, const gdb_byte *start,
1847 struct dwarf2_cie_table *cie_table,
1848 struct dwarf2_fde_table *fde_table,
1849 enum eh_frame_type entry_type)
1851 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
1852 const gdb_byte *buf, *end;
1854 unsigned int bytes_read;
1857 ULONGEST cie_pointer;
1862 length = read_initial_length (unit->abfd, buf, &bytes_read);
1866 /* Are we still within the section? */
1867 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1873 /* Distinguish between 32 and 64-bit encoded frame info. */
1874 dwarf64_p = (bytes_read == 12);
1876 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1880 cie_id = DW64_CIE_ID;
1886 cie_pointer = read_8_bytes (unit->abfd, buf);
1891 cie_pointer = read_4_bytes (unit->abfd, buf);
1895 if (cie_pointer == cie_id)
1897 /* This is a CIE. */
1898 struct dwarf2_cie *cie;
1900 unsigned int cie_version;
1902 /* Check that a CIE was expected. */
1903 if ((entry_type & EH_CIE_TYPE_ID) == 0)
1904 error (_("Found a CIE when not expecting it."));
1906 /* Record the offset into the .debug_frame section of this CIE. */
1907 cie_pointer = start - unit->dwarf_frame_buffer;
1909 /* Check whether we've already read it. */
1910 if (find_cie (cie_table, cie_pointer))
1913 cie = (struct dwarf2_cie *)
1914 obstack_alloc (&unit->objfile->objfile_obstack,
1915 sizeof (struct dwarf2_cie));
1916 cie->initial_instructions = NULL;
1917 cie->cie_pointer = cie_pointer;
1919 /* The encoding for FDE's in a normal .debug_frame section
1920 depends on the target address size. */
1921 cie->encoding = DW_EH_PE_absptr;
1923 /* We'll determine the final value later, but we need to
1924 initialize it conservatively. */
1925 cie->signal_frame = 0;
1927 /* Check version number. */
1928 cie_version = read_1_byte (unit->abfd, buf);
1929 if (cie_version != 1 && cie_version != 3 && cie_version != 4)
1931 cie->version = cie_version;
1934 /* Interpret the interesting bits of the augmentation. */
1935 cie->augmentation = augmentation = (char *) buf;
1936 buf += (strlen (augmentation) + 1);
1938 /* Ignore armcc augmentations. We only use them for quirks,
1939 and that doesn't happen until later. */
1940 if (strncmp (augmentation, "armcc", 5) == 0)
1941 augmentation += strlen (augmentation);
1943 /* The GCC 2.x "eh" augmentation has a pointer immediately
1944 following the augmentation string, so it must be handled
1946 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1949 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1953 if (cie->version >= 4)
1955 /* FIXME: check that this is the same as from the CU header. */
1956 cie->addr_size = read_1_byte (unit->abfd, buf);
1958 cie->segment_size = read_1_byte (unit->abfd, buf);
1963 cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch);
1964 cie->segment_size = 0;
1966 /* Address values in .eh_frame sections are defined to have the
1967 target's pointer size. Watchout: This breaks frame info for
1968 targets with pointer size < address size, unless a .debug_frame
1969 section exists as well. */
1971 cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1973 cie->ptr_size = cie->addr_size;
1975 buf = gdb_read_uleb128 (buf, end, &uleb128);
1978 cie->code_alignment_factor = uleb128;
1980 buf = gdb_read_sleb128 (buf, end, &sleb128);
1983 cie->data_alignment_factor = sleb128;
1985 if (cie_version == 1)
1987 cie->return_address_register = read_1_byte (unit->abfd, buf);
1992 buf = gdb_read_uleb128 (buf, end, &uleb128);
1995 cie->return_address_register = uleb128;
1998 cie->return_address_register
1999 = dwarf2_frame_adjust_regnum (gdbarch,
2000 cie->return_address_register,
2003 cie->saw_z_augmentation = (*augmentation == 'z');
2004 if (cie->saw_z_augmentation)
2008 buf = gdb_read_uleb128 (buf, end, &length);
2011 cie->initial_instructions = buf + length;
2015 while (*augmentation)
2017 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
2018 if (*augmentation == 'L')
2025 /* "R" indicates a byte indicating how FDE addresses are encoded. */
2026 else if (*augmentation == 'R')
2028 cie->encoding = *buf++;
2032 /* "P" indicates a personality routine in the CIE augmentation. */
2033 else if (*augmentation == 'P')
2035 /* Skip. Avoid indirection since we throw away the result. */
2036 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
2037 read_encoded_value (unit, encoding, cie->ptr_size,
2038 buf, &bytes_read, 0);
2043 /* "S" indicates a signal frame, such that the return
2044 address must not be decremented to locate the call frame
2045 info for the previous frame; it might even be the first
2046 instruction of a function, so decrementing it would take
2047 us to a different function. */
2048 else if (*augmentation == 'S')
2050 cie->signal_frame = 1;
2054 /* Otherwise we have an unknown augmentation. Assume that either
2055 there is no augmentation data, or we saw a 'z' prefix. */
2058 if (cie->initial_instructions)
2059 buf = cie->initial_instructions;
2064 cie->initial_instructions = buf;
2068 add_cie (cie_table, cie);
2072 /* This is a FDE. */
2073 struct dwarf2_fde *fde;
2075 /* Check that an FDE was expected. */
2076 if ((entry_type & EH_FDE_TYPE_ID) == 0)
2077 error (_("Found an FDE when not expecting it."));
2079 /* In an .eh_frame section, the CIE pointer is the delta between the
2080 address within the FDE where the CIE pointer is stored and the
2081 address of the CIE. Convert it to an offset into the .eh_frame
2085 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
2086 cie_pointer -= (dwarf64_p ? 8 : 4);
2089 /* In either case, validate the result is still within the section. */
2090 if (cie_pointer >= unit->dwarf_frame_size)
2093 fde = (struct dwarf2_fde *)
2094 obstack_alloc (&unit->objfile->objfile_obstack,
2095 sizeof (struct dwarf2_fde));
2096 fde->cie = find_cie (cie_table, cie_pointer);
2097 if (fde->cie == NULL)
2099 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
2100 eh_frame_p, cie_table, fde_table,
2102 fde->cie = find_cie (cie_table, cie_pointer);
2105 gdb_assert (fde->cie != NULL);
2107 fde->initial_location =
2108 read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
2109 buf, &bytes_read, 0);
2112 fde->address_range =
2113 read_encoded_value (unit, fde->cie->encoding & 0x0f,
2114 fde->cie->ptr_size, buf, &bytes_read, 0);
2117 /* A 'z' augmentation in the CIE implies the presence of an
2118 augmentation field in the FDE as well. The only thing known
2119 to be in here at present is the LSDA entry for EH. So we
2120 can skip the whole thing. */
2121 if (fde->cie->saw_z_augmentation)
2125 buf = gdb_read_uleb128 (buf, end, &length);
2133 fde->instructions = buf;
2136 fde->eh_frame_p = eh_frame_p;
2138 add_fde (fde_table, fde);
2144 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2145 expect an FDE or a CIE. */
2147 static const gdb_byte *
2148 decode_frame_entry (struct comp_unit *unit, const gdb_byte *start,
2150 struct dwarf2_cie_table *cie_table,
2151 struct dwarf2_fde_table *fde_table,
2152 enum eh_frame_type entry_type)
2154 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
2155 const gdb_byte *ret;
2156 ptrdiff_t start_offset;
2160 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
2161 cie_table, fde_table, entry_type);
2165 /* We have corrupt input data of some form. */
2167 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2168 and mismatches wrt padding and alignment of debug sections. */
2169 /* Note that there is no requirement in the standard for any
2170 alignment at all in the frame unwind sections. Testing for
2171 alignment before trying to interpret data would be incorrect.
2173 However, GCC traditionally arranged for frame sections to be
2174 sized such that the FDE length and CIE fields happen to be
2175 aligned (in theory, for performance). This, unfortunately,
2176 was done with .align directives, which had the side effect of
2177 forcing the section to be aligned by the linker.
2179 This becomes a problem when you have some other producer that
2180 creates frame sections that are not as strictly aligned. That
2181 produces a hole in the frame info that gets filled by the
2184 The GCC behaviour is arguably a bug, but it's effectively now
2185 part of the ABI, so we're now stuck with it, at least at the
2186 object file level. A smart linker may decide, in the process
2187 of compressing duplicate CIE information, that it can rewrite
2188 the entire output section without this extra padding. */
2190 start_offset = start - unit->dwarf_frame_buffer;
2191 if (workaround < ALIGN4 && (start_offset & 3) != 0)
2193 start += 4 - (start_offset & 3);
2194 workaround = ALIGN4;
2197 if (workaround < ALIGN8 && (start_offset & 7) != 0)
2199 start += 8 - (start_offset & 7);
2200 workaround = ALIGN8;
2204 /* Nothing left to try. Arrange to return as if we've consumed
2205 the entire input section. Hopefully we'll get valid info from
2206 the other of .debug_frame/.eh_frame. */
2208 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
2218 complaint (&symfile_complaints, _("\
2219 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2220 unit->dwarf_frame_section->owner->filename,
2221 unit->dwarf_frame_section->name);
2225 complaint (&symfile_complaints, _("\
2226 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2227 unit->dwarf_frame_section->owner->filename,
2228 unit->dwarf_frame_section->name);
2232 complaint (&symfile_complaints,
2233 _("Corrupt data in %s:%s"),
2234 unit->dwarf_frame_section->owner->filename,
2235 unit->dwarf_frame_section->name);
2243 qsort_fde_cmp (const void *a, const void *b)
2245 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
2246 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
2248 if (aa->initial_location == bb->initial_location)
2250 if (aa->address_range != bb->address_range
2251 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2252 /* Linker bug, e.g. gold/10400.
2253 Work around it by keeping stable sort order. */
2254 return (a < b) ? -1 : 1;
2256 /* Put eh_frame entries after debug_frame ones. */
2257 return aa->eh_frame_p - bb->eh_frame_p;
2260 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2264 dwarf2_build_frame_info (struct objfile *objfile)
2266 struct comp_unit *unit;
2267 const gdb_byte *frame_ptr;
2268 struct dwarf2_cie_table cie_table;
2269 struct dwarf2_fde_table fde_table;
2270 struct dwarf2_fde_table *fde_table2;
2271 volatile struct gdb_exception e;
2273 cie_table.num_entries = 0;
2274 cie_table.entries = NULL;
2276 fde_table.num_entries = 0;
2277 fde_table.entries = NULL;
2279 /* Build a minimal decoding of the DWARF2 compilation unit. */
2280 unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
2281 sizeof (struct comp_unit));
2282 unit->abfd = objfile->obfd;
2283 unit->objfile = objfile;
2287 if (objfile->separate_debug_objfile_backlink == NULL)
2289 /* Do not read .eh_frame from separate file as they must be also
2290 present in the main file. */
2291 dwarf2_get_section_info (objfile, DWARF2_EH_FRAME,
2292 &unit->dwarf_frame_section,
2293 &unit->dwarf_frame_buffer,
2294 &unit->dwarf_frame_size);
2295 if (unit->dwarf_frame_size)
2297 asection *got, *txt;
2299 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2300 that is used for the i386/amd64 target, which currently is
2301 the only target in GCC that supports/uses the
2302 DW_EH_PE_datarel encoding. */
2303 got = bfd_get_section_by_name (unit->abfd, ".got");
2305 unit->dbase = got->vma;
2307 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2309 txt = bfd_get_section_by_name (unit->abfd, ".text");
2311 unit->tbase = txt->vma;
2313 TRY_CATCH (e, RETURN_MASK_ERROR)
2315 frame_ptr = unit->dwarf_frame_buffer;
2316 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2317 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2318 &cie_table, &fde_table,
2319 EH_CIE_OR_FDE_TYPE_ID);
2324 warning (_("skipping .eh_frame info of %s: %s"),
2325 objfile_name (objfile), e.message);
2327 if (fde_table.num_entries != 0)
2329 xfree (fde_table.entries);
2330 fde_table.entries = NULL;
2331 fde_table.num_entries = 0;
2333 /* The cie_table is discarded by the next if. */
2336 if (cie_table.num_entries != 0)
2338 /* Reinit cie_table: debug_frame has different CIEs. */
2339 xfree (cie_table.entries);
2340 cie_table.num_entries = 0;
2341 cie_table.entries = NULL;
2346 dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME,
2347 &unit->dwarf_frame_section,
2348 &unit->dwarf_frame_buffer,
2349 &unit->dwarf_frame_size);
2350 if (unit->dwarf_frame_size)
2352 int num_old_fde_entries = fde_table.num_entries;
2354 TRY_CATCH (e, RETURN_MASK_ERROR)
2356 frame_ptr = unit->dwarf_frame_buffer;
2357 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2358 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2359 &cie_table, &fde_table,
2360 EH_CIE_OR_FDE_TYPE_ID);
2364 warning (_("skipping .debug_frame info of %s: %s"),
2365 objfile_name (objfile), e.message);
2367 if (fde_table.num_entries != 0)
2369 fde_table.num_entries = num_old_fde_entries;
2370 if (num_old_fde_entries == 0)
2372 xfree (fde_table.entries);
2373 fde_table.entries = NULL;
2377 fde_table.entries = xrealloc (fde_table.entries,
2378 fde_table.num_entries *
2379 sizeof (fde_table.entries[0]));
2382 fde_table.num_entries = num_old_fde_entries;
2383 /* The cie_table is discarded by the next if. */
2387 /* Discard the cie_table, it is no longer needed. */
2388 if (cie_table.num_entries != 0)
2390 xfree (cie_table.entries);
2391 cie_table.entries = NULL; /* Paranoia. */
2392 cie_table.num_entries = 0; /* Paranoia. */
2395 /* Copy fde_table to obstack: it is needed at runtime. */
2396 fde_table2 = (struct dwarf2_fde_table *)
2397 obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2));
2399 if (fde_table.num_entries == 0)
2401 fde_table2->entries = NULL;
2402 fde_table2->num_entries = 0;
2406 struct dwarf2_fde *fde_prev = NULL;
2407 struct dwarf2_fde *first_non_zero_fde = NULL;
2410 /* Prepare FDE table for lookups. */
2411 qsort (fde_table.entries, fde_table.num_entries,
2412 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2414 /* Check for leftovers from --gc-sections. The GNU linker sets
2415 the relevant symbols to zero, but doesn't zero the FDE *end*
2416 ranges because there's no relocation there. It's (offset,
2417 length), not (start, end). On targets where address zero is
2418 just another valid address this can be a problem, since the
2419 FDEs appear to be non-empty in the output --- we could pick
2420 out the wrong FDE. To work around this, when overlaps are
2421 detected, we prefer FDEs that do not start at zero.
2423 Start by finding the first FDE with non-zero start. Below
2424 we'll discard all FDEs that start at zero and overlap this
2426 for (i = 0; i < fde_table.num_entries; i++)
2428 struct dwarf2_fde *fde = fde_table.entries[i];
2430 if (fde->initial_location != 0)
2432 first_non_zero_fde = fde;
2437 /* Since we'll be doing bsearch, squeeze out identical (except
2438 for eh_frame_p) fde entries so bsearch result is predictable.
2439 Also discard leftovers from --gc-sections. */
2440 fde_table2->num_entries = 0;
2441 for (i = 0; i < fde_table.num_entries; i++)
2443 struct dwarf2_fde *fde = fde_table.entries[i];
2445 if (fde->initial_location == 0
2446 && first_non_zero_fde != NULL
2447 && (first_non_zero_fde->initial_location
2448 < fde->initial_location + fde->address_range))
2451 if (fde_prev != NULL
2452 && fde_prev->initial_location == fde->initial_location)
2455 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
2456 sizeof (fde_table.entries[0]));
2457 ++fde_table2->num_entries;
2460 fde_table2->entries = obstack_finish (&objfile->objfile_obstack);
2462 /* Discard the original fde_table. */
2463 xfree (fde_table.entries);
2466 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
2469 /* Provide a prototype to silence -Wmissing-prototypes. */
2470 void _initialize_dwarf2_frame (void);
2473 _initialize_dwarf2_frame (void)
2475 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2476 dwarf2_frame_objfile_data = register_objfile_data ();