1 /* Frame unwinder for frames with DWARF Call Frame Information.
3 Copyright (C) 2003-2005, 2007-2012 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"
36 #include "gdb_string.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 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 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 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_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 /* Convert the register to an integer. This returns a LONGEST
302 rather than a CORE_ADDR, but unpack_pointer does the same thing
303 under the covers, and this makes more sense for non-pointer
304 registers. Maybe read_reg and the associated interfaces should
305 deal with "struct value" instead of CORE_ADDR. */
306 return unpack_long (register_type (gdbarch, regnum), buf);
310 read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
312 read_memory (addr, buf, len);
315 /* Execute the required actions for both the DW_CFA_restore and
316 DW_CFA_restore_extended instructions. */
318 dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
319 struct dwarf2_frame_state *fs, int eh_frame_p)
323 gdb_assert (fs->initial.reg);
324 reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
325 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
327 /* Check if this register was explicitly initialized in the
328 CIE initial instructions. If not, default the rule to
330 if (reg < fs->initial.num_regs)
331 fs->regs.reg[reg] = fs->initial.reg[reg];
333 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
335 if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
336 complaint (&symfile_complaints, _("\
337 incomplete CFI data; DW_CFA_restore unspecified\n\
338 register %s (#%d) at %s"),
339 gdbarch_register_name
340 (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
341 gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
342 paddress (gdbarch, fs->pc));
345 /* Virtual method table for execute_stack_op below. */
347 static const struct dwarf_expr_context_funcs dwarf2_frame_ctx_funcs =
351 ctx_no_get_frame_base,
352 ctx_no_get_frame_cfa,
354 ctx_no_get_tls_address,
356 ctx_no_get_base_type,
357 ctx_no_push_dwarf_reg_entry_value,
358 ctx_no_get_addr_index
362 execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
363 CORE_ADDR offset, struct frame_info *this_frame,
364 CORE_ADDR initial, int initial_in_stack_memory)
366 struct dwarf_expr_context *ctx;
368 struct cleanup *old_chain;
370 ctx = new_dwarf_expr_context ();
371 old_chain = make_cleanup_free_dwarf_expr_context (ctx);
372 make_cleanup_value_free_to_mark (value_mark ());
374 ctx->gdbarch = get_frame_arch (this_frame);
375 ctx->addr_size = addr_size;
376 ctx->ref_addr_size = -1;
377 ctx->offset = offset;
378 ctx->baton = this_frame;
379 ctx->funcs = &dwarf2_frame_ctx_funcs;
381 dwarf_expr_push_address (ctx, initial, initial_in_stack_memory);
382 dwarf_expr_eval (ctx, exp, len);
384 if (ctx->location == DWARF_VALUE_MEMORY)
385 result = dwarf_expr_fetch_address (ctx, 0);
386 else if (ctx->location == DWARF_VALUE_REGISTER)
387 result = read_reg (this_frame, value_as_long (dwarf_expr_fetch (ctx, 0)));
390 /* This is actually invalid DWARF, but if we ever do run across
391 it somehow, we might as well support it. So, instead, report
392 it as unimplemented. */
394 Not implemented: computing unwound register using explicit value operator"));
397 do_cleanups (old_chain);
403 /* Execute FDE program from INSN_PTR possibly up to INSN_END or up to inferior
404 PC. Modify FS state accordingly. Return current INSN_PTR where the
405 execution has stopped, one can resume it on the next call. */
407 static const gdb_byte *
408 execute_cfa_program (struct dwarf2_fde *fde, const gdb_byte *insn_ptr,
409 const gdb_byte *insn_end, struct gdbarch *gdbarch,
410 CORE_ADDR pc, struct dwarf2_frame_state *fs)
412 int eh_frame_p = fde->eh_frame_p;
414 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
416 while (insn_ptr < insn_end && fs->pc <= pc)
418 gdb_byte insn = *insn_ptr++;
422 if ((insn & 0xc0) == DW_CFA_advance_loc)
423 fs->pc += (insn & 0x3f) * fs->code_align;
424 else if ((insn & 0xc0) == DW_CFA_offset)
427 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
428 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
429 offset = utmp * fs->data_align;
430 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
431 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
432 fs->regs.reg[reg].loc.offset = offset;
434 else if ((insn & 0xc0) == DW_CFA_restore)
437 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
444 fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
445 fde->cie->ptr_size, insn_ptr,
446 &bytes_read, fde->initial_location);
447 /* Apply the objfile offset for relocatable objects. */
448 fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
449 SECT_OFF_TEXT (fde->cie->unit->objfile));
450 insn_ptr += bytes_read;
453 case DW_CFA_advance_loc1:
454 utmp = extract_unsigned_integer (insn_ptr, 1, byte_order);
455 fs->pc += utmp * fs->code_align;
458 case DW_CFA_advance_loc2:
459 utmp = extract_unsigned_integer (insn_ptr, 2, byte_order);
460 fs->pc += utmp * fs->code_align;
463 case DW_CFA_advance_loc4:
464 utmp = extract_unsigned_integer (insn_ptr, 4, byte_order);
465 fs->pc += utmp * fs->code_align;
469 case DW_CFA_offset_extended:
470 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
471 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
472 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
473 offset = utmp * fs->data_align;
474 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
475 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
476 fs->regs.reg[reg].loc.offset = offset;
479 case DW_CFA_restore_extended:
480 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
481 dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
484 case DW_CFA_undefined:
485 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
486 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
487 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
488 fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
491 case DW_CFA_same_value:
492 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
493 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
494 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
495 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
498 case DW_CFA_register:
499 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
500 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
501 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
502 utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
503 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
504 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
505 fs->regs.reg[reg].loc.reg = utmp;
508 case DW_CFA_remember_state:
510 struct dwarf2_frame_state_reg_info *new_rs;
512 new_rs = XMALLOC (struct dwarf2_frame_state_reg_info);
514 fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
515 fs->regs.prev = new_rs;
519 case DW_CFA_restore_state:
521 struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
525 complaint (&symfile_complaints, _("\
526 bad CFI data; mismatched DW_CFA_restore_state at %s"),
527 paddress (gdbarch, fs->pc));
531 xfree (fs->regs.reg);
539 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
540 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
542 if (fs->armcc_cfa_offsets_sf)
543 utmp *= fs->data_align;
545 fs->regs.cfa_offset = utmp;
546 fs->regs.cfa_how = CFA_REG_OFFSET;
549 case DW_CFA_def_cfa_register:
550 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
551 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
554 fs->regs.cfa_how = CFA_REG_OFFSET;
557 case DW_CFA_def_cfa_offset:
558 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
560 if (fs->armcc_cfa_offsets_sf)
561 utmp *= fs->data_align;
563 fs->regs.cfa_offset = utmp;
564 /* cfa_how deliberately not set. */
570 case DW_CFA_def_cfa_expression:
571 insn_ptr = read_uleb128 (insn_ptr, insn_end,
572 &fs->regs.cfa_exp_len);
573 fs->regs.cfa_exp = insn_ptr;
574 fs->regs.cfa_how = CFA_EXP;
575 insn_ptr += fs->regs.cfa_exp_len;
578 case DW_CFA_expression:
579 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
580 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
581 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
582 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
583 fs->regs.reg[reg].loc.exp = insn_ptr;
584 fs->regs.reg[reg].exp_len = utmp;
585 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
589 case DW_CFA_offset_extended_sf:
590 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
591 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
592 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
593 offset *= fs->data_align;
594 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
595 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
596 fs->regs.reg[reg].loc.offset = offset;
599 case DW_CFA_val_offset:
600 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
601 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
602 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
603 offset = utmp * fs->data_align;
604 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
605 fs->regs.reg[reg].loc.offset = offset;
608 case DW_CFA_val_offset_sf:
609 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
610 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
611 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
612 offset *= fs->data_align;
613 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
614 fs->regs.reg[reg].loc.offset = offset;
617 case DW_CFA_val_expression:
618 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
619 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
620 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
621 fs->regs.reg[reg].loc.exp = insn_ptr;
622 fs->regs.reg[reg].exp_len = utmp;
623 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
627 case DW_CFA_def_cfa_sf:
628 insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->regs.cfa_reg);
629 fs->regs.cfa_reg = dwarf2_frame_adjust_regnum (gdbarch,
632 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
633 fs->regs.cfa_offset = offset * fs->data_align;
634 fs->regs.cfa_how = CFA_REG_OFFSET;
637 case DW_CFA_def_cfa_offset_sf:
638 insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
639 fs->regs.cfa_offset = offset * fs->data_align;
640 /* cfa_how deliberately not set. */
643 case DW_CFA_GNU_window_save:
644 /* This is SPARC-specific code, and contains hard-coded
645 constants for the register numbering scheme used by
646 GCC. Rather than having a architecture-specific
647 operation that's only ever used by a single
648 architecture, we provide the implementation here.
649 Incidentally that's what GCC does too in its
652 int size = register_size (gdbarch, 0);
654 dwarf2_frame_state_alloc_regs (&fs->regs, 32);
655 for (reg = 8; reg < 16; reg++)
657 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
658 fs->regs.reg[reg].loc.reg = reg + 16;
660 for (reg = 16; reg < 32; reg++)
662 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
663 fs->regs.reg[reg].loc.offset = (reg - 16) * size;
668 case DW_CFA_GNU_args_size:
670 insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
673 case DW_CFA_GNU_negative_offset_extended:
674 insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
675 reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
676 insn_ptr = read_uleb128 (insn_ptr, insn_end, &offset);
677 offset *= fs->data_align;
678 dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
679 fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
680 fs->regs.reg[reg].loc.offset = -offset;
684 internal_error (__FILE__, __LINE__,
685 _("Unknown CFI encountered."));
690 if (fs->initial.reg == NULL)
692 /* Don't allow remember/restore between CIE and FDE programs. */
693 dwarf2_frame_state_free_regs (fs->regs.prev);
694 fs->regs.prev = NULL;
701 /* Architecture-specific operations. */
703 /* Per-architecture data key. */
704 static struct gdbarch_data *dwarf2_frame_data;
706 struct dwarf2_frame_ops
708 /* Pre-initialize the register state REG for register REGNUM. */
709 void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
710 struct frame_info *);
712 /* Check whether the THIS_FRAME is a signal trampoline. */
713 int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
715 /* Convert .eh_frame register number to DWARF register number, or
716 adjust .debug_frame register number. */
717 int (*adjust_regnum) (struct gdbarch *, int, int);
720 /* Default architecture-specific register state initialization
724 dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
725 struct dwarf2_frame_state_reg *reg,
726 struct frame_info *this_frame)
728 /* If we have a register that acts as a program counter, mark it as
729 a destination for the return address. If we have a register that
730 serves as the stack pointer, arrange for it to be filled with the
731 call frame address (CFA). The other registers are marked as
734 We copy the return address to the program counter, since many
735 parts in GDB assume that it is possible to get the return address
736 by unwinding the program counter register. However, on ISA's
737 with a dedicated return address register, the CFI usually only
738 contains information to unwind that return address register.
740 The reason we're treating the stack pointer special here is
741 because in many cases GCC doesn't emit CFI for the stack pointer
742 and implicitly assumes that it is equal to the CFA. This makes
743 some sense since the DWARF specification (version 3, draft 8,
746 "Typically, the CFA is defined to be the value of the stack
747 pointer at the call site in the previous frame (which may be
748 different from its value on entry to the current frame)."
750 However, this isn't true for all platforms supported by GCC
751 (e.g. IBM S/390 and zSeries). Those architectures should provide
752 their own architecture-specific initialization function. */
754 if (regnum == gdbarch_pc_regnum (gdbarch))
755 reg->how = DWARF2_FRAME_REG_RA;
756 else if (regnum == gdbarch_sp_regnum (gdbarch))
757 reg->how = DWARF2_FRAME_REG_CFA;
760 /* Return a default for the architecture-specific operations. */
763 dwarf2_frame_init (struct obstack *obstack)
765 struct dwarf2_frame_ops *ops;
767 ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
768 ops->init_reg = dwarf2_frame_default_init_reg;
772 /* Set the architecture-specific register state initialization
773 function for GDBARCH to INIT_REG. */
776 dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
777 void (*init_reg) (struct gdbarch *, int,
778 struct dwarf2_frame_state_reg *,
779 struct frame_info *))
781 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
783 ops->init_reg = init_reg;
786 /* Pre-initialize the register state REG for register REGNUM. */
789 dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
790 struct dwarf2_frame_state_reg *reg,
791 struct frame_info *this_frame)
793 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
795 ops->init_reg (gdbarch, regnum, reg, this_frame);
798 /* Set the architecture-specific signal trampoline recognition
799 function for GDBARCH to SIGNAL_FRAME_P. */
802 dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
803 int (*signal_frame_p) (struct gdbarch *,
804 struct frame_info *))
806 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
808 ops->signal_frame_p = signal_frame_p;
811 /* Query the architecture-specific signal frame recognizer for
815 dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
816 struct frame_info *this_frame)
818 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
820 if (ops->signal_frame_p == NULL)
822 return ops->signal_frame_p (gdbarch, this_frame);
825 /* Set the architecture-specific adjustment of .eh_frame and .debug_frame
829 dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
830 int (*adjust_regnum) (struct gdbarch *,
833 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
835 ops->adjust_regnum = adjust_regnum;
838 /* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
842 dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch,
843 int regnum, int eh_frame_p)
845 struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
847 if (ops->adjust_regnum == NULL)
849 return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
853 dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
854 struct dwarf2_fde *fde)
858 s = find_pc_symtab (fs->pc);
862 if (producer_is_realview (s->producer))
864 if (fde->cie->version == 1)
865 fs->armcc_cfa_offsets_sf = 1;
867 if (fde->cie->version == 1)
868 fs->armcc_cfa_offsets_reversed = 1;
870 /* The reversed offset problem is present in some compilers
871 using DWARF3, but it was eventually fixed. Check the ARM
872 defined augmentations, which are in the format "armcc" followed
873 by a list of one-character options. The "+" option means
874 this problem is fixed (no quirk needed). If the armcc
875 augmentation is missing, the quirk is needed. */
876 if (fde->cie->version == 3
877 && (strncmp (fde->cie->augmentation, "armcc", 5) != 0
878 || strchr (fde->cie->augmentation + 5, '+') == NULL))
879 fs->armcc_cfa_offsets_reversed = 1;
887 dwarf2_compile_cfa_to_ax (struct agent_expr *expr, struct axs_value *loc,
888 struct gdbarch *gdbarch,
890 struct dwarf2_per_cu_data *data)
892 const int num_regs = gdbarch_num_regs (gdbarch)
893 + gdbarch_num_pseudo_regs (gdbarch);
894 struct dwarf2_fde *fde;
895 CORE_ADDR text_offset;
896 struct dwarf2_frame_state fs;
899 memset (&fs, 0, sizeof (struct dwarf2_frame_state));
903 /* Find the correct FDE. */
904 fde = dwarf2_frame_find_fde (&fs.pc, &text_offset);
906 error (_("Could not compute CFA; needed to translate this expression"));
908 /* Extract any interesting information from the CIE. */
909 fs.data_align = fde->cie->data_alignment_factor;
910 fs.code_align = fde->cie->code_alignment_factor;
911 fs.retaddr_column = fde->cie->return_address_register;
912 addr_size = fde->cie->addr_size;
914 /* Check for "quirks" - known bugs in producers. */
915 dwarf2_frame_find_quirks (&fs, fde);
917 /* First decode all the insns in the CIE. */
918 execute_cfa_program (fde, fde->cie->initial_instructions,
919 fde->cie->end, gdbarch, pc, &fs);
921 /* Save the initialized register set. */
922 fs.initial = fs.regs;
923 fs.initial.reg = dwarf2_frame_state_copy_regs (&fs.regs);
925 /* Then decode the insns in the FDE up to our target PC. */
926 execute_cfa_program (fde, fde->instructions, fde->end, gdbarch, pc, &fs);
928 /* Calculate the CFA. */
929 switch (fs.regs.cfa_how)
933 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, fs.regs.cfa_reg);
936 error (_("Unable to access DWARF register number %d"),
937 (int) fs.regs.cfa_reg); /* FIXME */
938 ax_reg (expr, regnum);
940 if (fs.regs.cfa_offset != 0)
942 if (fs.armcc_cfa_offsets_reversed)
943 ax_const_l (expr, -fs.regs.cfa_offset);
945 ax_const_l (expr, fs.regs.cfa_offset);
946 ax_simple (expr, aop_add);
952 ax_const_l (expr, text_offset);
953 dwarf2_compile_expr_to_ax (expr, loc, gdbarch, addr_size,
955 fs.regs.cfa_exp + fs.regs.cfa_exp_len,
960 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
965 struct dwarf2_frame_cache
967 /* DWARF Call Frame Address. */
970 /* Set if the return address column was marked as unavailable
971 (required non-collected memory or registers to compute). */
972 int unavailable_retaddr;
974 /* Set if the return address column was marked as undefined. */
975 int undefined_retaddr;
977 /* Saved registers, indexed by GDB register number, not by DWARF
979 struct dwarf2_frame_state_reg *reg;
981 /* Return address register. */
982 struct dwarf2_frame_state_reg retaddr_reg;
984 /* Target address size in bytes. */
987 /* The .text offset. */
988 CORE_ADDR text_offset;
990 /* If not NULL then this frame is the bottom frame of a TAILCALL_FRAME
991 sequence. If NULL then it is a normal case with no TAILCALL_FRAME
992 involved. Non-bottom frames of a virtual tail call frames chain use
993 dwarf2_tailcall_frame_unwind unwinder so this field does not apply for
995 void *tailcall_cache;
998 static struct dwarf2_frame_cache *
999 dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
1001 struct cleanup *old_chain;
1002 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1003 const int num_regs = gdbarch_num_regs (gdbarch)
1004 + gdbarch_num_pseudo_regs (gdbarch);
1005 struct dwarf2_frame_cache *cache;
1006 struct dwarf2_frame_state *fs;
1007 struct dwarf2_fde *fde;
1008 volatile struct gdb_exception ex;
1010 LONGEST entry_cfa_sp_offset;
1011 int entry_cfa_sp_offset_p = 0;
1012 const gdb_byte *instr;
1017 /* Allocate a new cache. */
1018 cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
1019 cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
1020 *this_cache = cache;
1022 /* Allocate and initialize the frame state. */
1023 fs = XZALLOC (struct dwarf2_frame_state);
1024 old_chain = make_cleanup (dwarf2_frame_state_free, fs);
1028 Note that if the next frame is never supposed to return (i.e. a call
1029 to abort), the compiler might optimize away the instruction at
1030 its return address. As a result the return address will
1031 point at some random instruction, and the CFI for that
1032 instruction is probably worthless to us. GCC's unwinder solves
1033 this problem by substracting 1 from the return address to get an
1034 address in the middle of a presumed call instruction (or the
1035 instruction in the associated delay slot). This should only be
1036 done for "normal" frames and not for resume-type frames (signal
1037 handlers, sentinel frames, dummy frames). The function
1038 get_frame_address_in_block does just this. It's not clear how
1039 reliable the method is though; there is the potential for the
1040 register state pre-call being different to that on return. */
1041 fs->pc = get_frame_address_in_block (this_frame);
1043 /* Find the correct FDE. */
1044 fde = dwarf2_frame_find_fde (&fs->pc, &cache->text_offset);
1045 gdb_assert (fde != NULL);
1047 /* Extract any interesting information from the CIE. */
1048 fs->data_align = fde->cie->data_alignment_factor;
1049 fs->code_align = fde->cie->code_alignment_factor;
1050 fs->retaddr_column = fde->cie->return_address_register;
1051 cache->addr_size = fde->cie->addr_size;
1053 /* Check for "quirks" - known bugs in producers. */
1054 dwarf2_frame_find_quirks (fs, fde);
1056 /* First decode all the insns in the CIE. */
1057 execute_cfa_program (fde, fde->cie->initial_instructions,
1058 fde->cie->end, gdbarch, get_frame_pc (this_frame), fs);
1060 /* Save the initialized register set. */
1061 fs->initial = fs->regs;
1062 fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
1064 if (get_frame_func_if_available (this_frame, &entry_pc))
1066 /* Decode the insns in the FDE up to the entry PC. */
1067 instr = execute_cfa_program (fde, fde->instructions, fde->end, gdbarch,
1070 if (fs->regs.cfa_how == CFA_REG_OFFSET
1071 && (gdbarch_dwarf2_reg_to_regnum (gdbarch, fs->regs.cfa_reg)
1072 == gdbarch_sp_regnum (gdbarch)))
1074 entry_cfa_sp_offset = fs->regs.cfa_offset;
1075 entry_cfa_sp_offset_p = 1;
1079 instr = fde->instructions;
1081 /* Then decode the insns in the FDE up to our target PC. */
1082 execute_cfa_program (fde, instr, fde->end, gdbarch,
1083 get_frame_pc (this_frame), fs);
1085 TRY_CATCH (ex, RETURN_MASK_ERROR)
1087 /* Calculate the CFA. */
1088 switch (fs->regs.cfa_how)
1090 case CFA_REG_OFFSET:
1091 cache->cfa = read_reg (this_frame, fs->regs.cfa_reg);
1092 if (fs->armcc_cfa_offsets_reversed)
1093 cache->cfa -= fs->regs.cfa_offset;
1095 cache->cfa += fs->regs.cfa_offset;
1100 execute_stack_op (fs->regs.cfa_exp, fs->regs.cfa_exp_len,
1101 cache->addr_size, cache->text_offset,
1106 internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
1111 if (ex.error == NOT_AVAILABLE_ERROR)
1113 cache->unavailable_retaddr = 1;
1117 throw_exception (ex);
1120 /* Initialize the register state. */
1124 for (regnum = 0; regnum < num_regs; regnum++)
1125 dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], this_frame);
1128 /* Go through the DWARF2 CFI generated table and save its register
1129 location information in the cache. Note that we don't skip the
1130 return address column; it's perfectly all right for it to
1131 correspond to a real register. If it doesn't correspond to a
1132 real register, or if we shouldn't treat it as such,
1133 gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
1134 the range [0, gdbarch_num_regs). */
1136 int column; /* CFI speak for "register number". */
1138 for (column = 0; column < fs->regs.num_regs; column++)
1140 /* Use the GDB register number as the destination index. */
1141 int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
1143 /* If there's no corresponding GDB register, ignore it. */
1144 if (regnum < 0 || regnum >= num_regs)
1147 /* NOTE: cagney/2003-09-05: CFI should specify the disposition
1148 of all debug info registers. If it doesn't, complain (but
1149 not too loudly). It turns out that GCC assumes that an
1150 unspecified register implies "same value" when CFI (draft
1151 7) specifies nothing at all. Such a register could equally
1152 be interpreted as "undefined". Also note that this check
1153 isn't sufficient; it only checks that all registers in the
1154 range [0 .. max column] are specified, and won't detect
1155 problems when a debug info register falls outside of the
1156 table. We need a way of iterating through all the valid
1157 DWARF2 register numbers. */
1158 if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
1160 if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
1161 complaint (&symfile_complaints, _("\
1162 incomplete CFI data; unspecified registers (e.g., %s) at %s"),
1163 gdbarch_register_name (gdbarch, regnum),
1164 paddress (gdbarch, fs->pc));
1167 cache->reg[regnum] = fs->regs.reg[column];
1171 /* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
1172 we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
1176 for (regnum = 0; regnum < num_regs; regnum++)
1178 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
1179 || cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
1181 struct dwarf2_frame_state_reg *retaddr_reg =
1182 &fs->regs.reg[fs->retaddr_column];
1184 /* It seems rather bizarre to specify an "empty" column as
1185 the return adress column. However, this is exactly
1186 what GCC does on some targets. It turns out that GCC
1187 assumes that the return address can be found in the
1188 register corresponding to the return address column.
1189 Incidentally, that's how we should treat a return
1190 address column specifying "same value" too. */
1191 if (fs->retaddr_column < fs->regs.num_regs
1192 && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
1193 && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
1195 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1196 cache->reg[regnum] = *retaddr_reg;
1198 cache->retaddr_reg = *retaddr_reg;
1202 if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
1204 cache->reg[regnum].loc.reg = fs->retaddr_column;
1205 cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
1209 cache->retaddr_reg.loc.reg = fs->retaddr_column;
1210 cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
1217 if (fs->retaddr_column < fs->regs.num_regs
1218 && fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
1219 cache->undefined_retaddr = 1;
1221 do_cleanups (old_chain);
1223 /* Try to find a virtual tail call frames chain with bottom (callee) frame
1224 starting at THIS_FRAME. */
1225 dwarf2_tailcall_sniffer_first (this_frame, &cache->tailcall_cache,
1226 (entry_cfa_sp_offset_p
1227 ? &entry_cfa_sp_offset : NULL));
1232 static enum unwind_stop_reason
1233 dwarf2_frame_unwind_stop_reason (struct frame_info *this_frame,
1236 struct dwarf2_frame_cache *cache
1237 = dwarf2_frame_cache (this_frame, this_cache);
1239 if (cache->unavailable_retaddr)
1240 return UNWIND_UNAVAILABLE;
1242 if (cache->undefined_retaddr)
1243 return UNWIND_OUTERMOST;
1245 return UNWIND_NO_REASON;
1249 dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
1250 struct frame_id *this_id)
1252 struct dwarf2_frame_cache *cache =
1253 dwarf2_frame_cache (this_frame, this_cache);
1255 if (cache->unavailable_retaddr)
1258 if (cache->undefined_retaddr)
1261 (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
1264 static struct value *
1265 dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache,
1268 struct gdbarch *gdbarch = get_frame_arch (this_frame);
1269 struct dwarf2_frame_cache *cache =
1270 dwarf2_frame_cache (this_frame, this_cache);
1274 /* Non-bottom frames of a virtual tail call frames chain use
1275 dwarf2_tailcall_frame_unwind unwinder so this code does not apply for
1276 them. If dwarf2_tailcall_prev_register_first does not have specific value
1277 unwind the register, tail call frames are assumed to have the register set
1278 of the top caller. */
1279 if (cache->tailcall_cache)
1283 val = dwarf2_tailcall_prev_register_first (this_frame,
1284 &cache->tailcall_cache,
1290 switch (cache->reg[regnum].how)
1292 case DWARF2_FRAME_REG_UNDEFINED:
1293 /* If CFI explicitly specified that the value isn't defined,
1294 mark it as optimized away; the value isn't available. */
1295 return frame_unwind_got_optimized (this_frame, regnum);
1297 case DWARF2_FRAME_REG_SAVED_OFFSET:
1298 addr = cache->cfa + cache->reg[regnum].loc.offset;
1299 return frame_unwind_got_memory (this_frame, regnum, addr);
1301 case DWARF2_FRAME_REG_SAVED_REG:
1303 = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
1304 return frame_unwind_got_register (this_frame, regnum, realnum);
1306 case DWARF2_FRAME_REG_SAVED_EXP:
1307 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1308 cache->reg[regnum].exp_len,
1309 cache->addr_size, cache->text_offset,
1310 this_frame, cache->cfa, 1);
1311 return frame_unwind_got_memory (this_frame, regnum, addr);
1313 case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
1314 addr = cache->cfa + cache->reg[regnum].loc.offset;
1315 return frame_unwind_got_constant (this_frame, regnum, addr);
1317 case DWARF2_FRAME_REG_SAVED_VAL_EXP:
1318 addr = execute_stack_op (cache->reg[regnum].loc.exp,
1319 cache->reg[regnum].exp_len,
1320 cache->addr_size, cache->text_offset,
1321 this_frame, cache->cfa, 1);
1322 return frame_unwind_got_constant (this_frame, regnum, addr);
1324 case DWARF2_FRAME_REG_UNSPECIFIED:
1325 /* GCC, in its infinite wisdom decided to not provide unwind
1326 information for registers that are "same value". Since
1327 DWARF2 (3 draft 7) doesn't define such behavior, said
1328 registers are actually undefined (which is different to CFI
1329 "undefined"). Code above issues a complaint about this.
1330 Here just fudge the books, assume GCC, and that the value is
1331 more inner on the stack. */
1332 return frame_unwind_got_register (this_frame, regnum, regnum);
1334 case DWARF2_FRAME_REG_SAME_VALUE:
1335 return frame_unwind_got_register (this_frame, regnum, regnum);
1337 case DWARF2_FRAME_REG_CFA:
1338 return frame_unwind_got_address (this_frame, regnum, cache->cfa);
1340 case DWARF2_FRAME_REG_CFA_OFFSET:
1341 addr = cache->cfa + cache->reg[regnum].loc.offset;
1342 return frame_unwind_got_address (this_frame, regnum, addr);
1344 case DWARF2_FRAME_REG_RA_OFFSET:
1345 addr = cache->reg[regnum].loc.offset;
1346 regnum = gdbarch_dwarf2_reg_to_regnum
1347 (gdbarch, cache->retaddr_reg.loc.reg);
1348 addr += get_frame_register_unsigned (this_frame, regnum);
1349 return frame_unwind_got_address (this_frame, regnum, addr);
1351 case DWARF2_FRAME_REG_FN:
1352 return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum);
1355 internal_error (__FILE__, __LINE__, _("Unknown register rule."));
1359 /* Proxy for tailcall_frame_dealloc_cache for bottom frame of a virtual tail
1360 call frames chain. */
1363 dwarf2_frame_dealloc_cache (struct frame_info *self, void *this_cache)
1365 struct dwarf2_frame_cache *cache = dwarf2_frame_cache (self, &this_cache);
1367 if (cache->tailcall_cache)
1368 dwarf2_tailcall_frame_unwind.dealloc_cache (self, cache->tailcall_cache);
1372 dwarf2_frame_sniffer (const struct frame_unwind *self,
1373 struct frame_info *this_frame, void **this_cache)
1375 /* Grab an address that is guarenteed to reside somewhere within the
1376 function. get_frame_pc(), with a no-return next function, can
1377 end up returning something past the end of this function's body.
1378 If the frame we're sniffing for is a signal frame whose start
1379 address is placed on the stack by the OS, its FDE must
1380 extend one byte before its start address or we could potentially
1381 select the FDE of the previous function. */
1382 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1383 struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr, NULL);
1388 /* On some targets, signal trampolines may have unwind information.
1389 We need to recognize them so that we set the frame type
1392 if (fde->cie->signal_frame
1393 || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
1395 return self->type == SIGTRAMP_FRAME;
1397 if (self->type != NORMAL_FRAME)
1400 /* Preinitializa the cache so that TAILCALL_FRAME can find the record by
1401 dwarf2_tailcall_sniffer_first. */
1402 dwarf2_frame_cache (this_frame, this_cache);
1407 static const struct frame_unwind dwarf2_frame_unwind =
1410 dwarf2_frame_unwind_stop_reason,
1411 dwarf2_frame_this_id,
1412 dwarf2_frame_prev_register,
1414 dwarf2_frame_sniffer,
1415 dwarf2_frame_dealloc_cache
1418 static const struct frame_unwind dwarf2_signal_frame_unwind =
1421 dwarf2_frame_unwind_stop_reason,
1422 dwarf2_frame_this_id,
1423 dwarf2_frame_prev_register,
1425 dwarf2_frame_sniffer,
1427 /* TAILCALL_CACHE can never be in such frame to need dealloc_cache. */
1431 /* Append the DWARF-2 frame unwinders to GDBARCH's list. */
1434 dwarf2_append_unwinders (struct gdbarch *gdbarch)
1436 /* TAILCALL_FRAME must be first to find the record by
1437 dwarf2_tailcall_sniffer_first. */
1438 frame_unwind_append_unwinder (gdbarch, &dwarf2_tailcall_frame_unwind);
1440 frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind);
1441 frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_frame_unwind);
1445 /* There is no explicitly defined relationship between the CFA and the
1446 location of frame's local variables and arguments/parameters.
1447 Therefore, frame base methods on this page should probably only be
1448 used as a last resort, just to avoid printing total garbage as a
1449 response to the "info frame" command. */
1452 dwarf2_frame_base_address (struct frame_info *this_frame, void **this_cache)
1454 struct dwarf2_frame_cache *cache =
1455 dwarf2_frame_cache (this_frame, this_cache);
1460 static const struct frame_base dwarf2_frame_base =
1462 &dwarf2_frame_unwind,
1463 dwarf2_frame_base_address,
1464 dwarf2_frame_base_address,
1465 dwarf2_frame_base_address
1468 const struct frame_base *
1469 dwarf2_frame_base_sniffer (struct frame_info *this_frame)
1471 CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
1473 if (dwarf2_frame_find_fde (&block_addr, NULL))
1474 return &dwarf2_frame_base;
1479 /* Compute the CFA for THIS_FRAME, but only if THIS_FRAME came from
1480 the DWARF unwinder. This is used to implement
1481 DW_OP_call_frame_cfa. */
1484 dwarf2_frame_cfa (struct frame_info *this_frame)
1486 while (get_frame_type (this_frame) == INLINE_FRAME)
1487 this_frame = get_prev_frame (this_frame);
1488 /* This restriction could be lifted if other unwinders are known to
1489 compute the frame base in a way compatible with the DWARF
1491 if (!frame_unwinder_is (this_frame, &dwarf2_frame_unwind)
1492 && !frame_unwinder_is (this_frame, &dwarf2_tailcall_frame_unwind))
1493 error (_("can't compute CFA for this frame"));
1494 if (get_frame_unwind_stop_reason (this_frame) == UNWIND_UNAVAILABLE)
1495 throw_error (NOT_AVAILABLE_ERROR,
1496 _("can't compute CFA for this frame: "
1497 "required registers or memory are unavailable"));
1498 return get_frame_base (this_frame);
1501 const struct objfile_data *dwarf2_frame_objfile_data;
1504 read_1_byte (bfd *abfd, gdb_byte *buf)
1506 return bfd_get_8 (abfd, buf);
1510 read_4_bytes (bfd *abfd, gdb_byte *buf)
1512 return bfd_get_32 (abfd, buf);
1516 read_8_bytes (bfd *abfd, gdb_byte *buf)
1518 return bfd_get_64 (abfd, buf);
1522 read_unsigned_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1525 unsigned int num_read;
1535 byte = bfd_get_8 (abfd, (bfd_byte *) buf);
1538 result |= ((byte & 0x7f) << shift);
1541 while (byte & 0x80);
1543 *bytes_read_ptr = num_read;
1549 read_signed_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1553 unsigned int num_read;
1562 byte = bfd_get_8 (abfd, (bfd_byte *) buf);
1565 result |= ((byte & 0x7f) << shift);
1568 while (byte & 0x80);
1570 if (shift < 8 * sizeof (result) && (byte & 0x40))
1571 result |= -(((LONGEST)1) << shift);
1573 *bytes_read_ptr = num_read;
1579 read_initial_length (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
1583 result = bfd_get_32 (abfd, buf);
1584 if (result == 0xffffffff)
1586 result = bfd_get_64 (abfd, buf + 4);
1587 *bytes_read_ptr = 12;
1590 *bytes_read_ptr = 4;
1596 /* Pointer encoding helper functions. */
1598 /* GCC supports exception handling based on DWARF2 CFI. However, for
1599 technical reasons, it encodes addresses in its FDE's in a different
1600 way. Several "pointer encodings" are supported. The encoding
1601 that's used for a particular FDE is determined by the 'R'
1602 augmentation in the associated CIE. The argument of this
1603 augmentation is a single byte.
1605 The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
1606 LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
1607 the address is signed or unsigned. Bits 4, 5 and 6 encode how the
1608 address should be interpreted (absolute, relative to the current
1609 position in the FDE, ...). Bit 7, indicates that the address
1610 should be dereferenced. */
1613 encoding_for_size (unsigned int size)
1618 return DW_EH_PE_udata2;
1620 return DW_EH_PE_udata4;
1622 return DW_EH_PE_udata8;
1624 internal_error (__FILE__, __LINE__, _("Unsupported address size"));
1629 read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
1630 int ptr_len, const gdb_byte *buf,
1631 unsigned int *bytes_read_ptr,
1632 CORE_ADDR func_base)
1637 /* GCC currently doesn't generate DW_EH_PE_indirect encodings for
1639 if (encoding & DW_EH_PE_indirect)
1640 internal_error (__FILE__, __LINE__,
1641 _("Unsupported encoding: DW_EH_PE_indirect"));
1643 *bytes_read_ptr = 0;
1645 switch (encoding & 0x70)
1647 case DW_EH_PE_absptr:
1650 case DW_EH_PE_pcrel:
1651 base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
1652 base += (buf - unit->dwarf_frame_buffer);
1654 case DW_EH_PE_datarel:
1657 case DW_EH_PE_textrel:
1660 case DW_EH_PE_funcrel:
1663 case DW_EH_PE_aligned:
1665 offset = buf - unit->dwarf_frame_buffer;
1666 if ((offset % ptr_len) != 0)
1668 *bytes_read_ptr = ptr_len - (offset % ptr_len);
1669 buf += *bytes_read_ptr;
1673 internal_error (__FILE__, __LINE__,
1674 _("Invalid or unsupported encoding"));
1677 if ((encoding & 0x07) == 0x00)
1679 encoding |= encoding_for_size (ptr_len);
1680 if (bfd_get_sign_extend_vma (unit->abfd))
1681 encoding |= DW_EH_PE_signed;
1684 switch (encoding & 0x0f)
1686 case DW_EH_PE_uleb128:
1689 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1691 *bytes_read_ptr += read_uleb128 (buf, end_buf, &value) - buf;
1692 return base + value;
1694 case DW_EH_PE_udata2:
1695 *bytes_read_ptr += 2;
1696 return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
1697 case DW_EH_PE_udata4:
1698 *bytes_read_ptr += 4;
1699 return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
1700 case DW_EH_PE_udata8:
1701 *bytes_read_ptr += 8;
1702 return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
1703 case DW_EH_PE_sleb128:
1706 const gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
1708 *bytes_read_ptr += read_sleb128 (buf, end_buf, &value) - buf;
1709 return base + value;
1711 case DW_EH_PE_sdata2:
1712 *bytes_read_ptr += 2;
1713 return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
1714 case DW_EH_PE_sdata4:
1715 *bytes_read_ptr += 4;
1716 return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
1717 case DW_EH_PE_sdata8:
1718 *bytes_read_ptr += 8;
1719 return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
1721 internal_error (__FILE__, __LINE__,
1722 _("Invalid or unsupported encoding"));
1728 bsearch_cie_cmp (const void *key, const void *element)
1730 ULONGEST cie_pointer = *(ULONGEST *) key;
1731 struct dwarf2_cie *cie = *(struct dwarf2_cie **) element;
1733 if (cie_pointer == cie->cie_pointer)
1736 return (cie_pointer < cie->cie_pointer) ? -1 : 1;
1739 /* Find CIE with the given CIE_POINTER in CIE_TABLE. */
1740 static struct dwarf2_cie *
1741 find_cie (struct dwarf2_cie_table *cie_table, ULONGEST cie_pointer)
1743 struct dwarf2_cie **p_cie;
1745 /* The C standard (ISO/IEC 9899:TC2) requires the BASE argument to
1746 bsearch be non-NULL. */
1747 if (cie_table->entries == NULL)
1749 gdb_assert (cie_table->num_entries == 0);
1753 p_cie = bsearch (&cie_pointer, cie_table->entries, cie_table->num_entries,
1754 sizeof (cie_table->entries[0]), bsearch_cie_cmp);
1760 /* Add a pointer to new CIE to the CIE_TABLE, allocating space for it. */
1762 add_cie (struct dwarf2_cie_table *cie_table, struct dwarf2_cie *cie)
1764 const int n = cie_table->num_entries;
1767 || cie_table->entries[n - 1]->cie_pointer < cie->cie_pointer);
1769 cie_table->entries =
1770 xrealloc (cie_table->entries, (n + 1) * sizeof (cie_table->entries[0]));
1771 cie_table->entries[n] = cie;
1772 cie_table->num_entries = n + 1;
1776 bsearch_fde_cmp (const void *key, const void *element)
1778 CORE_ADDR seek_pc = *(CORE_ADDR *) key;
1779 struct dwarf2_fde *fde = *(struct dwarf2_fde **) element;
1781 if (seek_pc < fde->initial_location)
1783 if (seek_pc < fde->initial_location + fde->address_range)
1788 /* Find the FDE for *PC. Return a pointer to the FDE, and store the
1789 inital location associated with it into *PC. */
1791 static struct dwarf2_fde *
1792 dwarf2_frame_find_fde (CORE_ADDR *pc, CORE_ADDR *out_offset)
1794 struct objfile *objfile;
1796 ALL_OBJFILES (objfile)
1798 struct dwarf2_fde_table *fde_table;
1799 struct dwarf2_fde **p_fde;
1803 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1804 if (fde_table == NULL)
1806 dwarf2_build_frame_info (objfile);
1807 fde_table = objfile_data (objfile, dwarf2_frame_objfile_data);
1809 gdb_assert (fde_table != NULL);
1811 if (fde_table->num_entries == 0)
1814 gdb_assert (objfile->section_offsets);
1815 offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
1817 gdb_assert (fde_table->num_entries > 0);
1818 if (*pc < offset + fde_table->entries[0]->initial_location)
1821 seek_pc = *pc - offset;
1822 p_fde = bsearch (&seek_pc, fde_table->entries, fde_table->num_entries,
1823 sizeof (fde_table->entries[0]), bsearch_fde_cmp);
1826 *pc = (*p_fde)->initial_location + offset;
1828 *out_offset = offset;
1835 /* Add a pointer to new FDE to the FDE_TABLE, allocating space for it. */
1837 add_fde (struct dwarf2_fde_table *fde_table, struct dwarf2_fde *fde)
1839 if (fde->address_range == 0)
1840 /* Discard useless FDEs. */
1843 fde_table->num_entries += 1;
1844 fde_table->entries =
1845 xrealloc (fde_table->entries,
1846 fde_table->num_entries * sizeof (fde_table->entries[0]));
1847 fde_table->entries[fde_table->num_entries - 1] = fde;
1850 #ifdef CC_HAS_LONG_LONG
1851 #define DW64_CIE_ID 0xffffffffffffffffULL
1853 #define DW64_CIE_ID ~0
1856 /* Defines the type of eh_frames that are expected to be decoded: CIE, FDE
1861 EH_CIE_TYPE_ID = 1 << 0,
1862 EH_FDE_TYPE_ID = 1 << 1,
1863 EH_CIE_OR_FDE_TYPE_ID = EH_CIE_TYPE_ID | EH_FDE_TYPE_ID
1866 static gdb_byte *decode_frame_entry (struct comp_unit *unit, gdb_byte *start,
1868 struct dwarf2_cie_table *cie_table,
1869 struct dwarf2_fde_table *fde_table,
1870 enum eh_frame_type entry_type);
1872 /* Decode the next CIE or FDE, entry_type specifies the expected type.
1873 Return NULL if invalid input, otherwise the next byte to be processed. */
1876 decode_frame_entry_1 (struct comp_unit *unit, gdb_byte *start, int eh_frame_p,
1877 struct dwarf2_cie_table *cie_table,
1878 struct dwarf2_fde_table *fde_table,
1879 enum eh_frame_type entry_type)
1881 struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
1882 gdb_byte *buf, *end;
1884 unsigned int bytes_read;
1887 ULONGEST cie_pointer;
1890 length = read_initial_length (unit->abfd, buf, &bytes_read);
1894 /* Are we still within the section? */
1895 if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
1901 /* Distinguish between 32 and 64-bit encoded frame info. */
1902 dwarf64_p = (bytes_read == 12);
1904 /* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
1908 cie_id = DW64_CIE_ID;
1914 cie_pointer = read_8_bytes (unit->abfd, buf);
1919 cie_pointer = read_4_bytes (unit->abfd, buf);
1923 if (cie_pointer == cie_id)
1925 /* This is a CIE. */
1926 struct dwarf2_cie *cie;
1928 unsigned int cie_version;
1930 /* Check that a CIE was expected. */
1931 if ((entry_type & EH_CIE_TYPE_ID) == 0)
1932 error (_("Found a CIE when not expecting it."));
1934 /* Record the offset into the .debug_frame section of this CIE. */
1935 cie_pointer = start - unit->dwarf_frame_buffer;
1937 /* Check whether we've already read it. */
1938 if (find_cie (cie_table, cie_pointer))
1941 cie = (struct dwarf2_cie *)
1942 obstack_alloc (&unit->objfile->objfile_obstack,
1943 sizeof (struct dwarf2_cie));
1944 cie->initial_instructions = NULL;
1945 cie->cie_pointer = cie_pointer;
1947 /* The encoding for FDE's in a normal .debug_frame section
1948 depends on the target address size. */
1949 cie->encoding = DW_EH_PE_absptr;
1951 /* We'll determine the final value later, but we need to
1952 initialize it conservatively. */
1953 cie->signal_frame = 0;
1955 /* Check version number. */
1956 cie_version = read_1_byte (unit->abfd, buf);
1957 if (cie_version != 1 && cie_version != 3 && cie_version != 4)
1959 cie->version = cie_version;
1962 /* Interpret the interesting bits of the augmentation. */
1963 cie->augmentation = augmentation = (char *) buf;
1964 buf += (strlen (augmentation) + 1);
1966 /* Ignore armcc augmentations. We only use them for quirks,
1967 and that doesn't happen until later. */
1968 if (strncmp (augmentation, "armcc", 5) == 0)
1969 augmentation += strlen (augmentation);
1971 /* The GCC 2.x "eh" augmentation has a pointer immediately
1972 following the augmentation string, so it must be handled
1974 if (augmentation[0] == 'e' && augmentation[1] == 'h')
1977 buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
1981 if (cie->version >= 4)
1983 /* FIXME: check that this is the same as from the CU header. */
1984 cie->addr_size = read_1_byte (unit->abfd, buf);
1986 cie->segment_size = read_1_byte (unit->abfd, buf);
1991 cie->addr_size = gdbarch_dwarf2_addr_size (gdbarch);
1992 cie->segment_size = 0;
1994 /* Address values in .eh_frame sections are defined to have the
1995 target's pointer size. Watchout: This breaks frame info for
1996 targets with pointer size < address size, unless a .debug_frame
1997 section exists as well. */
1999 cie->ptr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
2001 cie->ptr_size = cie->addr_size;
2003 cie->code_alignment_factor =
2004 read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
2007 cie->data_alignment_factor =
2008 read_signed_leb128 (unit->abfd, buf, &bytes_read);
2011 if (cie_version == 1)
2013 cie->return_address_register = read_1_byte (unit->abfd, buf);
2017 cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf,
2019 cie->return_address_register
2020 = dwarf2_frame_adjust_regnum (gdbarch,
2021 cie->return_address_register,
2026 cie->saw_z_augmentation = (*augmentation == 'z');
2027 if (cie->saw_z_augmentation)
2031 length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
2035 cie->initial_instructions = buf + length;
2039 while (*augmentation)
2041 /* "L" indicates a byte showing how the LSDA pointer is encoded. */
2042 if (*augmentation == 'L')
2049 /* "R" indicates a byte indicating how FDE addresses are encoded. */
2050 else if (*augmentation == 'R')
2052 cie->encoding = *buf++;
2056 /* "P" indicates a personality routine in the CIE augmentation. */
2057 else if (*augmentation == 'P')
2059 /* Skip. Avoid indirection since we throw away the result. */
2060 gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
2061 read_encoded_value (unit, encoding, cie->ptr_size,
2062 buf, &bytes_read, 0);
2067 /* "S" indicates a signal frame, such that the return
2068 address must not be decremented to locate the call frame
2069 info for the previous frame; it might even be the first
2070 instruction of a function, so decrementing it would take
2071 us to a different function. */
2072 else if (*augmentation == 'S')
2074 cie->signal_frame = 1;
2078 /* Otherwise we have an unknown augmentation. Assume that either
2079 there is no augmentation data, or we saw a 'z' prefix. */
2082 if (cie->initial_instructions)
2083 buf = cie->initial_instructions;
2088 cie->initial_instructions = buf;
2092 add_cie (cie_table, cie);
2096 /* This is a FDE. */
2097 struct dwarf2_fde *fde;
2099 /* Check that an FDE was expected. */
2100 if ((entry_type & EH_FDE_TYPE_ID) == 0)
2101 error (_("Found an FDE when not expecting it."));
2103 /* In an .eh_frame section, the CIE pointer is the delta between the
2104 address within the FDE where the CIE pointer is stored and the
2105 address of the CIE. Convert it to an offset into the .eh_frame
2109 cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
2110 cie_pointer -= (dwarf64_p ? 8 : 4);
2113 /* In either case, validate the result is still within the section. */
2114 if (cie_pointer >= unit->dwarf_frame_size)
2117 fde = (struct dwarf2_fde *)
2118 obstack_alloc (&unit->objfile->objfile_obstack,
2119 sizeof (struct dwarf2_fde));
2120 fde->cie = find_cie (cie_table, cie_pointer);
2121 if (fde->cie == NULL)
2123 decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
2124 eh_frame_p, cie_table, fde_table,
2126 fde->cie = find_cie (cie_table, cie_pointer);
2129 gdb_assert (fde->cie != NULL);
2131 fde->initial_location =
2132 read_encoded_value (unit, fde->cie->encoding, fde->cie->ptr_size,
2133 buf, &bytes_read, 0);
2136 fde->address_range =
2137 read_encoded_value (unit, fde->cie->encoding & 0x0f,
2138 fde->cie->ptr_size, buf, &bytes_read, 0);
2141 /* A 'z' augmentation in the CIE implies the presence of an
2142 augmentation field in the FDE as well. The only thing known
2143 to be in here at present is the LSDA entry for EH. So we
2144 can skip the whole thing. */
2145 if (fde->cie->saw_z_augmentation)
2149 length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
2150 buf += bytes_read + length;
2155 fde->instructions = buf;
2158 fde->eh_frame_p = eh_frame_p;
2160 add_fde (fde_table, fde);
2166 /* Read a CIE or FDE in BUF and decode it. Entry_type specifies whether we
2167 expect an FDE or a CIE. */
2170 decode_frame_entry (struct comp_unit *unit, gdb_byte *start, int eh_frame_p,
2171 struct dwarf2_cie_table *cie_table,
2172 struct dwarf2_fde_table *fde_table,
2173 enum eh_frame_type entry_type)
2175 enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
2177 ptrdiff_t start_offset;
2181 ret = decode_frame_entry_1 (unit, start, eh_frame_p,
2182 cie_table, fde_table, entry_type);
2186 /* We have corrupt input data of some form. */
2188 /* ??? Try, weakly, to work around compiler/assembler/linker bugs
2189 and mismatches wrt padding and alignment of debug sections. */
2190 /* Note that there is no requirement in the standard for any
2191 alignment at all in the frame unwind sections. Testing for
2192 alignment before trying to interpret data would be incorrect.
2194 However, GCC traditionally arranged for frame sections to be
2195 sized such that the FDE length and CIE fields happen to be
2196 aligned (in theory, for performance). This, unfortunately,
2197 was done with .align directives, which had the side effect of
2198 forcing the section to be aligned by the linker.
2200 This becomes a problem when you have some other producer that
2201 creates frame sections that are not as strictly aligned. That
2202 produces a hole in the frame info that gets filled by the
2205 The GCC behaviour is arguably a bug, but it's effectively now
2206 part of the ABI, so we're now stuck with it, at least at the
2207 object file level. A smart linker may decide, in the process
2208 of compressing duplicate CIE information, that it can rewrite
2209 the entire output section without this extra padding. */
2211 start_offset = start - unit->dwarf_frame_buffer;
2212 if (workaround < ALIGN4 && (start_offset & 3) != 0)
2214 start += 4 - (start_offset & 3);
2215 workaround = ALIGN4;
2218 if (workaround < ALIGN8 && (start_offset & 7) != 0)
2220 start += 8 - (start_offset & 7);
2221 workaround = ALIGN8;
2225 /* Nothing left to try. Arrange to return as if we've consumed
2226 the entire input section. Hopefully we'll get valid info from
2227 the other of .debug_frame/.eh_frame. */
2229 ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
2239 complaint (&symfile_complaints, _("\
2240 Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
2241 unit->dwarf_frame_section->owner->filename,
2242 unit->dwarf_frame_section->name);
2246 complaint (&symfile_complaints, _("\
2247 Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
2248 unit->dwarf_frame_section->owner->filename,
2249 unit->dwarf_frame_section->name);
2253 complaint (&symfile_complaints,
2254 _("Corrupt data in %s:%s"),
2255 unit->dwarf_frame_section->owner->filename,
2256 unit->dwarf_frame_section->name);
2264 qsort_fde_cmp (const void *a, const void *b)
2266 struct dwarf2_fde *aa = *(struct dwarf2_fde **)a;
2267 struct dwarf2_fde *bb = *(struct dwarf2_fde **)b;
2269 if (aa->initial_location == bb->initial_location)
2271 if (aa->address_range != bb->address_range
2272 && aa->eh_frame_p == 0 && bb->eh_frame_p == 0)
2273 /* Linker bug, e.g. gold/10400.
2274 Work around it by keeping stable sort order. */
2275 return (a < b) ? -1 : 1;
2277 /* Put eh_frame entries after debug_frame ones. */
2278 return aa->eh_frame_p - bb->eh_frame_p;
2281 return (aa->initial_location < bb->initial_location) ? -1 : 1;
2285 dwarf2_build_frame_info (struct objfile *objfile)
2287 struct comp_unit *unit;
2288 gdb_byte *frame_ptr;
2289 struct dwarf2_cie_table cie_table;
2290 struct dwarf2_fde_table fde_table;
2291 struct dwarf2_fde_table *fde_table2;
2292 volatile struct gdb_exception e;
2294 cie_table.num_entries = 0;
2295 cie_table.entries = NULL;
2297 fde_table.num_entries = 0;
2298 fde_table.entries = NULL;
2300 /* Build a minimal decoding of the DWARF2 compilation unit. */
2301 unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
2302 sizeof (struct comp_unit));
2303 unit->abfd = objfile->obfd;
2304 unit->objfile = objfile;
2308 if (objfile->separate_debug_objfile_backlink == NULL)
2310 /* Do not read .eh_frame from separate file as they must be also
2311 present in the main file. */
2312 dwarf2_get_section_info (objfile, DWARF2_EH_FRAME,
2313 &unit->dwarf_frame_section,
2314 &unit->dwarf_frame_buffer,
2315 &unit->dwarf_frame_size);
2316 if (unit->dwarf_frame_size)
2318 asection *got, *txt;
2320 /* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
2321 that is used for the i386/amd64 target, which currently is
2322 the only target in GCC that supports/uses the
2323 DW_EH_PE_datarel encoding. */
2324 got = bfd_get_section_by_name (unit->abfd, ".got");
2326 unit->dbase = got->vma;
2328 /* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
2330 txt = bfd_get_section_by_name (unit->abfd, ".text");
2332 unit->tbase = txt->vma;
2334 TRY_CATCH (e, RETURN_MASK_ERROR)
2336 frame_ptr = unit->dwarf_frame_buffer;
2337 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2338 frame_ptr = decode_frame_entry (unit, frame_ptr, 1,
2339 &cie_table, &fde_table,
2340 EH_CIE_OR_FDE_TYPE_ID);
2345 warning (_("skipping .eh_frame info of %s: %s"),
2346 objfile->name, e.message);
2348 if (fde_table.num_entries != 0)
2350 xfree (fde_table.entries);
2351 fde_table.entries = NULL;
2352 fde_table.num_entries = 0;
2354 /* The cie_table is discarded by the next if. */
2357 if (cie_table.num_entries != 0)
2359 /* Reinit cie_table: debug_frame has different CIEs. */
2360 xfree (cie_table.entries);
2361 cie_table.num_entries = 0;
2362 cie_table.entries = NULL;
2367 dwarf2_get_section_info (objfile, DWARF2_DEBUG_FRAME,
2368 &unit->dwarf_frame_section,
2369 &unit->dwarf_frame_buffer,
2370 &unit->dwarf_frame_size);
2371 if (unit->dwarf_frame_size)
2373 int num_old_fde_entries = fde_table.num_entries;
2375 TRY_CATCH (e, RETURN_MASK_ERROR)
2377 frame_ptr = unit->dwarf_frame_buffer;
2378 while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
2379 frame_ptr = decode_frame_entry (unit, frame_ptr, 0,
2380 &cie_table, &fde_table,
2381 EH_CIE_OR_FDE_TYPE_ID);
2385 warning (_("skipping .debug_frame info of %s: %s"),
2386 objfile->name, e.message);
2388 if (fde_table.num_entries != 0)
2390 fde_table.num_entries = num_old_fde_entries;
2391 if (num_old_fde_entries == 0)
2393 xfree (fde_table.entries);
2394 fde_table.entries = NULL;
2398 fde_table.entries = xrealloc (fde_table.entries,
2399 fde_table.num_entries *
2400 sizeof (fde_table.entries[0]));
2403 fde_table.num_entries = num_old_fde_entries;
2404 /* The cie_table is discarded by the next if. */
2408 /* Discard the cie_table, it is no longer needed. */
2409 if (cie_table.num_entries != 0)
2411 xfree (cie_table.entries);
2412 cie_table.entries = NULL; /* Paranoia. */
2413 cie_table.num_entries = 0; /* Paranoia. */
2416 /* Copy fde_table to obstack: it is needed at runtime. */
2417 fde_table2 = (struct dwarf2_fde_table *)
2418 obstack_alloc (&objfile->objfile_obstack, sizeof (*fde_table2));
2420 if (fde_table.num_entries == 0)
2422 fde_table2->entries = NULL;
2423 fde_table2->num_entries = 0;
2427 struct dwarf2_fde *fde_prev = NULL;
2428 struct dwarf2_fde *first_non_zero_fde = NULL;
2431 /* Prepare FDE table for lookups. */
2432 qsort (fde_table.entries, fde_table.num_entries,
2433 sizeof (fde_table.entries[0]), qsort_fde_cmp);
2435 /* Check for leftovers from --gc-sections. The GNU linker sets
2436 the relevant symbols to zero, but doesn't zero the FDE *end*
2437 ranges because there's no relocation there. It's (offset,
2438 length), not (start, end). On targets where address zero is
2439 just another valid address this can be a problem, since the
2440 FDEs appear to be non-empty in the output --- we could pick
2441 out the wrong FDE. To work around this, when overlaps are
2442 detected, we prefer FDEs that do not start at zero.
2444 Start by finding the first FDE with non-zero start. Below
2445 we'll discard all FDEs that start at zero and overlap this
2447 for (i = 0; i < fde_table.num_entries; i++)
2449 struct dwarf2_fde *fde = fde_table.entries[i];
2451 if (fde->initial_location != 0)
2453 first_non_zero_fde = fde;
2458 /* Since we'll be doing bsearch, squeeze out identical (except
2459 for eh_frame_p) fde entries so bsearch result is predictable.
2460 Also discard leftovers from --gc-sections. */
2461 fde_table2->num_entries = 0;
2462 for (i = 0; i < fde_table.num_entries; i++)
2464 struct dwarf2_fde *fde = fde_table.entries[i];
2466 if (fde->initial_location == 0
2467 && first_non_zero_fde != NULL
2468 && (first_non_zero_fde->initial_location
2469 < fde->initial_location + fde->address_range))
2472 if (fde_prev != NULL
2473 && fde_prev->initial_location == fde->initial_location)
2476 obstack_grow (&objfile->objfile_obstack, &fde_table.entries[i],
2477 sizeof (fde_table.entries[0]));
2478 ++fde_table2->num_entries;
2481 fde_table2->entries = obstack_finish (&objfile->objfile_obstack);
2483 /* Discard the original fde_table. */
2484 xfree (fde_table.entries);
2487 set_objfile_data (objfile, dwarf2_frame_objfile_data, fde_table2);
2490 /* Provide a prototype to silence -Wmissing-prototypes. */
2491 void _initialize_dwarf2_frame (void);
2494 _initialize_dwarf2_frame (void)
2496 dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
2497 dwarf2_frame_objfile_data = register_objfile_data ();