mirror of
https://sourceware.org/git/binutils-gdb.git
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5e2b427df3
(get_objfile_arch): Add prototype. * objfiles.c: Include "arch-utils.h". (allocate_objfile): Look up gdbarch associated with bfd. (get_objfile_arch): New function. * Makefile (objfiles.o): Update dependencies. * dwarf2-frame.c (decode_frame_entry_1): Replace current_gdbarch by objfile arch. * dwarf2loc.c (dwarf_expr_read_reg): Replace current_gdbarch by frame arch. (locexpr_describe_location): Replace current_gdbarch by objfile arch. * dwarf2read.c (die_type): Replace current_gdbarch by objfile arch. (dwarf2_add_field): Likewise. (read_tag_pointer_type): Likewise. (read_base_type): Likewise. (new_symbol): Likewise. * coffread.c (decode_type): Add OBJFILE argument. Update callers. (decode_base_type, decode_function_type): Likewise. (coff_read_struct_type, coff_read_enum_type): Likewise. (coff_symtab_read): Replace current_gdbarch by objfile arch. (decode_base_type): Likewise. (coff_read_enum_type): Likewise. (coff_read_struct_type): Replace current_objfile by OBJFILE argument. (coff_read_enum_type): Likewise. * dbxread.c (read_dbx_symtab): Replace current_gdbarch by objfile arch. (end_psymtab): Likewise. (process_one_symbol): Likewise. * mdebugread.c (parse_symbol): Replace current_gdbarch by objfile arch. (parse_procedure): Likewise. (parse_partial_symbols): Likewise. * somread.c (som_symtab_read): Replace current_gdbarch by objfile arch. * stabsread.c (define_symbol): Replace current_gdbarch by objfile arch. Replace static pcc_promotion_type and pcc_unsigned_promotion_type by built-in types. (read_range_type): Replace current_gdbarch by objfile arch. Replace static range_index_type by built-in type. (read_one_struct_field): Replace current_gdbarch by objfile arch. (read_enum_type): Likewise. * xcoffread.c (read_xcoff_symtab): Replace current_gdbarch by objfile arch.
2055 lines
59 KiB
C
2055 lines
59 KiB
C
/* Frame unwinder for frames with DWARF Call Frame Information.
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Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
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Contributed by Mark Kettenis.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "defs.h"
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#include "dwarf2expr.h"
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#include "elf/dwarf2.h"
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#include "frame.h"
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#include "frame-base.h"
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#include "frame-unwind.h"
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#include "gdbcore.h"
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#include "gdbtypes.h"
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#include "symtab.h"
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#include "objfiles.h"
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#include "regcache.h"
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#include "value.h"
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#include "gdb_assert.h"
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#include "gdb_string.h"
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#include "complaints.h"
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#include "dwarf2-frame.h"
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struct comp_unit;
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/* Call Frame Information (CFI). */
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/* Common Information Entry (CIE). */
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struct dwarf2_cie
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{
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/* Computation Unit for this CIE. */
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struct comp_unit *unit;
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/* Offset into the .debug_frame section where this CIE was found.
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Used to identify this CIE. */
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ULONGEST cie_pointer;
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/* Constant that is factored out of all advance location
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instructions. */
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ULONGEST code_alignment_factor;
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/* Constants that is factored out of all offset instructions. */
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LONGEST data_alignment_factor;
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/* Return address column. */
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ULONGEST return_address_register;
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/* Instruction sequence to initialize a register set. */
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gdb_byte *initial_instructions;
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gdb_byte *end;
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/* Saved augmentation, in case it's needed later. */
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char *augmentation;
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/* Encoding of addresses. */
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gdb_byte encoding;
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/* Target address size in bytes. */
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int addr_size;
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/* True if a 'z' augmentation existed. */
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unsigned char saw_z_augmentation;
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/* True if an 'S' augmentation existed. */
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unsigned char signal_frame;
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/* The version recorded in the CIE. */
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unsigned char version;
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struct dwarf2_cie *next;
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};
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/* Frame Description Entry (FDE). */
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struct dwarf2_fde
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{
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/* CIE for this FDE. */
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struct dwarf2_cie *cie;
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/* First location associated with this FDE. */
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CORE_ADDR initial_location;
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/* Number of bytes of program instructions described by this FDE. */
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CORE_ADDR address_range;
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/* Instruction sequence. */
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gdb_byte *instructions;
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gdb_byte *end;
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/* True if this FDE is read from a .eh_frame instead of a .debug_frame
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section. */
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unsigned char eh_frame_p;
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struct dwarf2_fde *next;
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};
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/* A minimal decoding of DWARF2 compilation units. We only decode
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what's needed to get to the call frame information. */
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struct comp_unit
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{
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/* Keep the bfd convenient. */
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bfd *abfd;
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struct objfile *objfile;
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/* Linked list of CIEs for this object. */
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struct dwarf2_cie *cie;
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/* Pointer to the .debug_frame section loaded into memory. */
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gdb_byte *dwarf_frame_buffer;
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/* Length of the loaded .debug_frame section. */
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unsigned long dwarf_frame_size;
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/* Pointer to the .debug_frame section. */
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asection *dwarf_frame_section;
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/* Base for DW_EH_PE_datarel encodings. */
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bfd_vma dbase;
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/* Base for DW_EH_PE_textrel encodings. */
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bfd_vma tbase;
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};
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static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc);
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static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum,
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int eh_frame_p);
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static CORE_ADDR read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
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int ptr_len, gdb_byte *buf,
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unsigned int *bytes_read_ptr,
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CORE_ADDR func_base);
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/* Structure describing a frame state. */
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struct dwarf2_frame_state
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{
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/* Each register save state can be described in terms of a CFA slot,
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another register, or a location expression. */
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struct dwarf2_frame_state_reg_info
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{
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struct dwarf2_frame_state_reg *reg;
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int num_regs;
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/* Used to implement DW_CFA_remember_state. */
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struct dwarf2_frame_state_reg_info *prev;
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} regs;
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LONGEST cfa_offset;
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ULONGEST cfa_reg;
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gdb_byte *cfa_exp;
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enum {
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CFA_UNSET,
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CFA_REG_OFFSET,
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CFA_EXP
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} cfa_how;
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/* The PC described by the current frame state. */
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CORE_ADDR pc;
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/* Initial register set from the CIE.
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Used to implement DW_CFA_restore. */
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struct dwarf2_frame_state_reg_info initial;
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/* The information we care about from the CIE. */
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LONGEST data_align;
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ULONGEST code_align;
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ULONGEST retaddr_column;
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/* Flags for known producer quirks. */
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/* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa
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and DW_CFA_def_cfa_offset takes a factored offset. */
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int armcc_cfa_offsets_sf;
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/* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that
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the CFA is defined as REG - OFFSET rather than REG + OFFSET. */
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int armcc_cfa_offsets_reversed;
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};
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/* Store the length the expression for the CFA in the `cfa_reg' field,
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which is unused in that case. */
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#define cfa_exp_len cfa_reg
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/* Assert that the register set RS is large enough to store gdbarch_num_regs
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columns. If necessary, enlarge the register set. */
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static void
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dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs,
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int num_regs)
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{
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size_t size = sizeof (struct dwarf2_frame_state_reg);
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if (num_regs <= rs->num_regs)
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return;
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rs->reg = (struct dwarf2_frame_state_reg *)
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xrealloc (rs->reg, num_regs * size);
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/* Initialize newly allocated registers. */
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memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size);
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rs->num_regs = num_regs;
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}
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/* Copy the register columns in register set RS into newly allocated
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memory and return a pointer to this newly created copy. */
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static struct dwarf2_frame_state_reg *
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dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs)
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{
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size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg);
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struct dwarf2_frame_state_reg *reg;
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reg = (struct dwarf2_frame_state_reg *) xmalloc (size);
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memcpy (reg, rs->reg, size);
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return reg;
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}
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/* Release the memory allocated to register set RS. */
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static void
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dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs)
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{
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if (rs)
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{
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dwarf2_frame_state_free_regs (rs->prev);
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xfree (rs->reg);
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xfree (rs);
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}
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}
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/* Release the memory allocated to the frame state FS. */
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static void
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dwarf2_frame_state_free (void *p)
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{
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struct dwarf2_frame_state *fs = p;
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dwarf2_frame_state_free_regs (fs->initial.prev);
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dwarf2_frame_state_free_regs (fs->regs.prev);
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xfree (fs->initial.reg);
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xfree (fs->regs.reg);
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xfree (fs);
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}
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/* Helper functions for execute_stack_op. */
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static CORE_ADDR
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read_reg (void *baton, int reg)
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{
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struct frame_info *next_frame = (struct frame_info *) baton;
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struct gdbarch *gdbarch = get_frame_arch (next_frame);
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int regnum;
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gdb_byte *buf;
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regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
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buf = alloca (register_size (gdbarch, regnum));
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frame_unwind_register (next_frame, regnum, buf);
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/* Convert the register to an integer. This returns a LONGEST
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rather than a CORE_ADDR, but unpack_pointer does the same thing
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under the covers, and this makes more sense for non-pointer
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registers. Maybe read_reg and the associated interfaces should
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deal with "struct value" instead of CORE_ADDR. */
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return unpack_long (register_type (gdbarch, regnum), buf);
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}
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static void
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read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
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{
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read_memory (addr, buf, len);
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}
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static void
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no_get_frame_base (void *baton, gdb_byte **start, size_t *length)
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{
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internal_error (__FILE__, __LINE__,
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_("Support for DW_OP_fbreg is unimplemented"));
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}
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static CORE_ADDR
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no_get_tls_address (void *baton, CORE_ADDR offset)
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{
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internal_error (__FILE__, __LINE__,
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_("Support for DW_OP_GNU_push_tls_address is unimplemented"));
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}
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/* Execute the required actions for both the DW_CFA_restore and
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DW_CFA_restore_extended instructions. */
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static void
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dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num,
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struct dwarf2_frame_state *fs, int eh_frame_p)
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{
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ULONGEST reg;
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gdb_assert (fs->initial.reg);
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reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p);
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dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
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/* Check if this register was explicitly initialized in the
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CIE initial instructions. If not, default the rule to
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UNSPECIFIED. */
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if (reg < fs->initial.num_regs)
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fs->regs.reg[reg] = fs->initial.reg[reg];
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else
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fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED;
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if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED)
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complaint (&symfile_complaints, _("\
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incomplete CFI data; DW_CFA_restore unspecified\n\
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register %s (#%d) at 0x%s"),
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gdbarch_register_name
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(gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)),
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gdbarch_dwarf2_reg_to_regnum (gdbarch, reg),
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paddr (fs->pc));
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}
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static CORE_ADDR
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execute_stack_op (gdb_byte *exp, ULONGEST len, int addr_size,
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struct frame_info *next_frame, CORE_ADDR initial)
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{
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struct dwarf_expr_context *ctx;
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CORE_ADDR result;
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ctx = new_dwarf_expr_context ();
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ctx->addr_size = addr_size;
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ctx->baton = next_frame;
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ctx->read_reg = read_reg;
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ctx->read_mem = read_mem;
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ctx->get_frame_base = no_get_frame_base;
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ctx->get_tls_address = no_get_tls_address;
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dwarf_expr_push (ctx, initial);
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dwarf_expr_eval (ctx, exp, len);
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result = dwarf_expr_fetch (ctx, 0);
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if (ctx->in_reg)
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result = read_reg (next_frame, result);
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free_dwarf_expr_context (ctx);
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return result;
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}
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static void
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execute_cfa_program (struct dwarf2_fde *fde, gdb_byte *insn_ptr,
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gdb_byte *insn_end, struct frame_info *next_frame,
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struct dwarf2_frame_state *fs)
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{
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int eh_frame_p = fde->eh_frame_p;
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CORE_ADDR pc = frame_pc_unwind (next_frame);
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int bytes_read;
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struct gdbarch *gdbarch = get_frame_arch (next_frame);
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while (insn_ptr < insn_end && fs->pc <= pc)
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{
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gdb_byte insn = *insn_ptr++;
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ULONGEST utmp, reg;
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LONGEST offset;
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if ((insn & 0xc0) == DW_CFA_advance_loc)
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fs->pc += (insn & 0x3f) * fs->code_align;
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else if ((insn & 0xc0) == DW_CFA_offset)
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{
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reg = insn & 0x3f;
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reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
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insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
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offset = utmp * fs->data_align;
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dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
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fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
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fs->regs.reg[reg].loc.offset = offset;
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}
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else if ((insn & 0xc0) == DW_CFA_restore)
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{
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reg = insn & 0x3f;
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dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
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}
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else
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{
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switch (insn)
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{
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case DW_CFA_set_loc:
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fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding,
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fde->cie->addr_size, insn_ptr,
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&bytes_read, fde->initial_location);
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/* Apply the objfile offset for relocatable objects. */
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fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets,
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SECT_OFF_TEXT (fde->cie->unit->objfile));
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insn_ptr += bytes_read;
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break;
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case DW_CFA_advance_loc1:
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utmp = extract_unsigned_integer (insn_ptr, 1);
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fs->pc += utmp * fs->code_align;
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insn_ptr++;
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break;
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case DW_CFA_advance_loc2:
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utmp = extract_unsigned_integer (insn_ptr, 2);
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fs->pc += utmp * fs->code_align;
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insn_ptr += 2;
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break;
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case DW_CFA_advance_loc4:
|
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utmp = extract_unsigned_integer (insn_ptr, 4);
|
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fs->pc += utmp * fs->code_align;
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insn_ptr += 4;
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break;
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case DW_CFA_offset_extended:
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insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
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reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
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insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
|
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offset = utmp * fs->data_align;
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dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
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fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
|
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fs->regs.reg[reg].loc.offset = offset;
|
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break;
|
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|
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case DW_CFA_restore_extended:
|
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insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
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dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p);
|
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break;
|
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|
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case DW_CFA_undefined:
|
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insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
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reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
|
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dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
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fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
|
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break;
|
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|
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case DW_CFA_same_value:
|
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insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
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reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
|
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dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
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fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
|
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break;
|
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|
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case DW_CFA_register:
|
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insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
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reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
|
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insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
|
||
utmp = dwarf2_frame_adjust_regnum (gdbarch, utmp, eh_frame_p);
|
||
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
|
||
fs->regs.reg[reg].loc.reg = utmp;
|
||
break;
|
||
|
||
case DW_CFA_remember_state:
|
||
{
|
||
struct dwarf2_frame_state_reg_info *new_rs;
|
||
|
||
new_rs = XMALLOC (struct dwarf2_frame_state_reg_info);
|
||
*new_rs = fs->regs;
|
||
fs->regs.reg = dwarf2_frame_state_copy_regs (&fs->regs);
|
||
fs->regs.prev = new_rs;
|
||
}
|
||
break;
|
||
|
||
case DW_CFA_restore_state:
|
||
{
|
||
struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
|
||
|
||
if (old_rs == NULL)
|
||
{
|
||
complaint (&symfile_complaints, _("\
|
||
bad CFI data; mismatched DW_CFA_restore_state at 0x%s"), paddr (fs->pc));
|
||
}
|
||
else
|
||
{
|
||
xfree (fs->regs.reg);
|
||
fs->regs = *old_rs;
|
||
xfree (old_rs);
|
||
}
|
||
}
|
||
break;
|
||
|
||
case DW_CFA_def_cfa:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg);
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
|
||
|
||
if (fs->armcc_cfa_offsets_sf)
|
||
utmp *= fs->data_align;
|
||
|
||
fs->cfa_offset = utmp;
|
||
fs->cfa_how = CFA_REG_OFFSET;
|
||
break;
|
||
|
||
case DW_CFA_def_cfa_register:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg);
|
||
fs->cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, fs->cfa_reg,
|
||
eh_frame_p);
|
||
fs->cfa_how = CFA_REG_OFFSET;
|
||
break;
|
||
|
||
case DW_CFA_def_cfa_offset:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
|
||
|
||
if (fs->armcc_cfa_offsets_sf)
|
||
utmp *= fs->data_align;
|
||
|
||
fs->cfa_offset = utmp;
|
||
/* cfa_how deliberately not set. */
|
||
break;
|
||
|
||
case DW_CFA_nop:
|
||
break;
|
||
|
||
case DW_CFA_def_cfa_expression:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_exp_len);
|
||
fs->cfa_exp = insn_ptr;
|
||
fs->cfa_how = CFA_EXP;
|
||
insn_ptr += fs->cfa_exp_len;
|
||
break;
|
||
|
||
case DW_CFA_expression:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
||
reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
|
||
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
|
||
fs->regs.reg[reg].loc.exp = insn_ptr;
|
||
fs->regs.reg[reg].exp_len = utmp;
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
|
||
insn_ptr += utmp;
|
||
break;
|
||
|
||
case DW_CFA_offset_extended_sf:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
||
reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
|
||
insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
|
||
offset *= fs->data_align;
|
||
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
|
||
fs->regs.reg[reg].loc.offset = offset;
|
||
break;
|
||
|
||
case DW_CFA_val_offset:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
||
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
|
||
offset = utmp * fs->data_align;
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
|
||
fs->regs.reg[reg].loc.offset = offset;
|
||
break;
|
||
|
||
case DW_CFA_val_offset_sf:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
||
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
||
insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
|
||
offset *= fs->data_align;
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_OFFSET;
|
||
fs->regs.reg[reg].loc.offset = offset;
|
||
break;
|
||
|
||
case DW_CFA_val_expression:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
||
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
|
||
fs->regs.reg[reg].loc.exp = insn_ptr;
|
||
fs->regs.reg[reg].exp_len = utmp;
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_VAL_EXP;
|
||
insn_ptr += utmp;
|
||
break;
|
||
|
||
case DW_CFA_def_cfa_sf:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg);
|
||
fs->cfa_reg = dwarf2_frame_adjust_regnum (gdbarch, fs->cfa_reg,
|
||
eh_frame_p);
|
||
insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
|
||
fs->cfa_offset = offset * fs->data_align;
|
||
fs->cfa_how = CFA_REG_OFFSET;
|
||
break;
|
||
|
||
case DW_CFA_def_cfa_offset_sf:
|
||
insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
|
||
fs->cfa_offset = offset * fs->data_align;
|
||
/* cfa_how deliberately not set. */
|
||
break;
|
||
|
||
case DW_CFA_GNU_window_save:
|
||
/* This is SPARC-specific code, and contains hard-coded
|
||
constants for the register numbering scheme used by
|
||
GCC. Rather than having a architecture-specific
|
||
operation that's only ever used by a single
|
||
architecture, we provide the implementation here.
|
||
Incidentally that's what GCC does too in its
|
||
unwinder. */
|
||
{
|
||
struct gdbarch *gdbarch = get_frame_arch (next_frame);
|
||
int size = register_size(gdbarch, 0);
|
||
dwarf2_frame_state_alloc_regs (&fs->regs, 32);
|
||
for (reg = 8; reg < 16; reg++)
|
||
{
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
|
||
fs->regs.reg[reg].loc.reg = reg + 16;
|
||
}
|
||
for (reg = 16; reg < 32; reg++)
|
||
{
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
|
||
fs->regs.reg[reg].loc.offset = (reg - 16) * size;
|
||
}
|
||
}
|
||
break;
|
||
|
||
case DW_CFA_GNU_args_size:
|
||
/* Ignored. */
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
|
||
break;
|
||
|
||
case DW_CFA_GNU_negative_offset_extended:
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
|
||
reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p);
|
||
insn_ptr = read_uleb128 (insn_ptr, insn_end, &offset);
|
||
offset *= fs->data_align;
|
||
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
|
||
fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
|
||
fs->regs.reg[reg].loc.offset = -offset;
|
||
break;
|
||
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("Unknown CFI encountered."));
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Don't allow remember/restore between CIE and FDE programs. */
|
||
dwarf2_frame_state_free_regs (fs->regs.prev);
|
||
fs->regs.prev = NULL;
|
||
}
|
||
|
||
|
||
/* Architecture-specific operations. */
|
||
|
||
/* Per-architecture data key. */
|
||
static struct gdbarch_data *dwarf2_frame_data;
|
||
|
||
struct dwarf2_frame_ops
|
||
{
|
||
/* Pre-initialize the register state REG for register REGNUM. */
|
||
void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *,
|
||
struct frame_info *);
|
||
|
||
/* Check whether the frame preceding NEXT_FRAME will be a signal
|
||
trampoline. */
|
||
int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
|
||
|
||
/* Convert .eh_frame register number to DWARF register number, or
|
||
adjust .debug_frame register number. */
|
||
int (*adjust_regnum) (struct gdbarch *, int, int);
|
||
};
|
||
|
||
/* Default architecture-specific register state initialization
|
||
function. */
|
||
|
||
static void
|
||
dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
|
||
struct dwarf2_frame_state_reg *reg,
|
||
struct frame_info *next_frame)
|
||
{
|
||
/* If we have a register that acts as a program counter, mark it as
|
||
a destination for the return address. If we have a register that
|
||
serves as the stack pointer, arrange for it to be filled with the
|
||
call frame address (CFA). The other registers are marked as
|
||
unspecified.
|
||
|
||
We copy the return address to the program counter, since many
|
||
parts in GDB assume that it is possible to get the return address
|
||
by unwinding the program counter register. However, on ISA's
|
||
with a dedicated return address register, the CFI usually only
|
||
contains information to unwind that return address register.
|
||
|
||
The reason we're treating the stack pointer special here is
|
||
because in many cases GCC doesn't emit CFI for the stack pointer
|
||
and implicitly assumes that it is equal to the CFA. This makes
|
||
some sense since the DWARF specification (version 3, draft 8,
|
||
p. 102) says that:
|
||
|
||
"Typically, the CFA is defined to be the value of the stack
|
||
pointer at the call site in the previous frame (which may be
|
||
different from its value on entry to the current frame)."
|
||
|
||
However, this isn't true for all platforms supported by GCC
|
||
(e.g. IBM S/390 and zSeries). Those architectures should provide
|
||
their own architecture-specific initialization function. */
|
||
|
||
if (regnum == gdbarch_pc_regnum (gdbarch))
|
||
reg->how = DWARF2_FRAME_REG_RA;
|
||
else if (regnum == gdbarch_sp_regnum (gdbarch))
|
||
reg->how = DWARF2_FRAME_REG_CFA;
|
||
}
|
||
|
||
/* Return a default for the architecture-specific operations. */
|
||
|
||
static void *
|
||
dwarf2_frame_init (struct obstack *obstack)
|
||
{
|
||
struct dwarf2_frame_ops *ops;
|
||
|
||
ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
|
||
ops->init_reg = dwarf2_frame_default_init_reg;
|
||
return ops;
|
||
}
|
||
|
||
/* Set the architecture-specific register state initialization
|
||
function for GDBARCH to INIT_REG. */
|
||
|
||
void
|
||
dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
|
||
void (*init_reg) (struct gdbarch *, int,
|
||
struct dwarf2_frame_state_reg *,
|
||
struct frame_info *))
|
||
{
|
||
struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
|
||
|
||
ops->init_reg = init_reg;
|
||
}
|
||
|
||
/* Pre-initialize the register state REG for register REGNUM. */
|
||
|
||
static void
|
||
dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
|
||
struct dwarf2_frame_state_reg *reg,
|
||
struct frame_info *next_frame)
|
||
{
|
||
struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
|
||
|
||
ops->init_reg (gdbarch, regnum, reg, next_frame);
|
||
}
|
||
|
||
/* Set the architecture-specific signal trampoline recognition
|
||
function for GDBARCH to SIGNAL_FRAME_P. */
|
||
|
||
void
|
||
dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
|
||
int (*signal_frame_p) (struct gdbarch *,
|
||
struct frame_info *))
|
||
{
|
||
struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
|
||
|
||
ops->signal_frame_p = signal_frame_p;
|
||
}
|
||
|
||
/* Query the architecture-specific signal frame recognizer for
|
||
NEXT_FRAME. */
|
||
|
||
static int
|
||
dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
|
||
struct frame_info *next_frame)
|
||
{
|
||
struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
|
||
|
||
if (ops->signal_frame_p == NULL)
|
||
return 0;
|
||
return ops->signal_frame_p (gdbarch, next_frame);
|
||
}
|
||
|
||
/* Set the architecture-specific adjustment of .eh_frame and .debug_frame
|
||
register numbers. */
|
||
|
||
void
|
||
dwarf2_frame_set_adjust_regnum (struct gdbarch *gdbarch,
|
||
int (*adjust_regnum) (struct gdbarch *,
|
||
int, int))
|
||
{
|
||
struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
|
||
|
||
ops->adjust_regnum = adjust_regnum;
|
||
}
|
||
|
||
/* Translate a .eh_frame register to DWARF register, or adjust a .debug_frame
|
||
register. */
|
||
|
||
static int
|
||
dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum, int eh_frame_p)
|
||
{
|
||
struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
|
||
|
||
if (ops->adjust_regnum == NULL)
|
||
return regnum;
|
||
return ops->adjust_regnum (gdbarch, regnum, eh_frame_p);
|
||
}
|
||
|
||
static void
|
||
dwarf2_frame_find_quirks (struct dwarf2_frame_state *fs,
|
||
struct dwarf2_fde *fde)
|
||
{
|
||
static const char *arm_idents[] = {
|
||
"ARM C Compiler, ADS",
|
||
"Thumb C Compiler, ADS",
|
||
"ARM C++ Compiler, ADS",
|
||
"Thumb C++ Compiler, ADS",
|
||
"ARM/Thumb C/C++ Compiler, RVCT"
|
||
};
|
||
int i;
|
||
|
||
struct symtab *s;
|
||
|
||
s = find_pc_symtab (fs->pc);
|
||
if (s == NULL || s->producer == NULL)
|
||
return;
|
||
|
||
for (i = 0; i < ARRAY_SIZE (arm_idents); i++)
|
||
if (strncmp (s->producer, arm_idents[i], strlen (arm_idents[i])) == 0)
|
||
{
|
||
if (fde->cie->version == 1)
|
||
fs->armcc_cfa_offsets_sf = 1;
|
||
|
||
if (fde->cie->version == 1)
|
||
fs->armcc_cfa_offsets_reversed = 1;
|
||
|
||
/* The reversed offset problem is present in some compilers
|
||
using DWARF3, but it was eventually fixed. Check the ARM
|
||
defined augmentations, which are in the format "armcc" followed
|
||
by a list of one-character options. The "+" option means
|
||
this problem is fixed (no quirk needed). If the armcc
|
||
augmentation is missing, the quirk is needed. */
|
||
if (fde->cie->version == 3
|
||
&& (strncmp (fde->cie->augmentation, "armcc", 5) != 0
|
||
|| strchr (fde->cie->augmentation + 5, '+') == NULL))
|
||
fs->armcc_cfa_offsets_reversed = 1;
|
||
|
||
return;
|
||
}
|
||
}
|
||
|
||
|
||
struct dwarf2_frame_cache
|
||
{
|
||
/* DWARF Call Frame Address. */
|
||
CORE_ADDR cfa;
|
||
|
||
/* Set if the return address column was marked as undefined. */
|
||
int undefined_retaddr;
|
||
|
||
/* Saved registers, indexed by GDB register number, not by DWARF
|
||
register number. */
|
||
struct dwarf2_frame_state_reg *reg;
|
||
|
||
/* Return address register. */
|
||
struct dwarf2_frame_state_reg retaddr_reg;
|
||
|
||
/* Target address size in bytes. */
|
||
int addr_size;
|
||
};
|
||
|
||
static struct dwarf2_frame_cache *
|
||
dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
|
||
{
|
||
struct cleanup *old_chain;
|
||
struct gdbarch *gdbarch = get_frame_arch (next_frame);
|
||
const int num_regs = gdbarch_num_regs (gdbarch)
|
||
+ gdbarch_num_pseudo_regs (gdbarch);
|
||
struct dwarf2_frame_cache *cache;
|
||
struct dwarf2_frame_state *fs;
|
||
struct dwarf2_fde *fde;
|
||
|
||
if (*this_cache)
|
||
return *this_cache;
|
||
|
||
/* Allocate a new cache. */
|
||
cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
|
||
cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
|
||
|
||
/* Allocate and initialize the frame state. */
|
||
fs = XMALLOC (struct dwarf2_frame_state);
|
||
memset (fs, 0, sizeof (struct dwarf2_frame_state));
|
||
old_chain = make_cleanup (dwarf2_frame_state_free, fs);
|
||
|
||
/* Unwind the PC.
|
||
|
||
Note that if NEXT_FRAME is never supposed to return (i.e. a call
|
||
to abort), the compiler might optimize away the instruction at
|
||
NEXT_FRAME's return address. As a result the return address will
|
||
point at some random instruction, and the CFI for that
|
||
instruction is probably worthless to us. GCC's unwinder solves
|
||
this problem by substracting 1 from the return address to get an
|
||
address in the middle of a presumed call instruction (or the
|
||
instruction in the associated delay slot). This should only be
|
||
done for "normal" frames and not for resume-type frames (signal
|
||
handlers, sentinel frames, dummy frames). The function
|
||
frame_unwind_address_in_block does just this. It's not clear how
|
||
reliable the method is though; there is the potential for the
|
||
register state pre-call being different to that on return. */
|
||
fs->pc = frame_unwind_address_in_block (next_frame, NORMAL_FRAME);
|
||
|
||
/* Find the correct FDE. */
|
||
fde = dwarf2_frame_find_fde (&fs->pc);
|
||
gdb_assert (fde != NULL);
|
||
|
||
/* Extract any interesting information from the CIE. */
|
||
fs->data_align = fde->cie->data_alignment_factor;
|
||
fs->code_align = fde->cie->code_alignment_factor;
|
||
fs->retaddr_column = fde->cie->return_address_register;
|
||
cache->addr_size = fde->cie->addr_size;
|
||
|
||
/* Check for "quirks" - known bugs in producers. */
|
||
dwarf2_frame_find_quirks (fs, fde);
|
||
|
||
/* First decode all the insns in the CIE. */
|
||
execute_cfa_program (fde, fde->cie->initial_instructions,
|
||
fde->cie->end, next_frame, fs);
|
||
|
||
/* Save the initialized register set. */
|
||
fs->initial = fs->regs;
|
||
fs->initial.reg = dwarf2_frame_state_copy_regs (&fs->regs);
|
||
|
||
/* Then decode the insns in the FDE up to our target PC. */
|
||
execute_cfa_program (fde, fde->instructions, fde->end, next_frame, fs);
|
||
|
||
/* Caclulate the CFA. */
|
||
switch (fs->cfa_how)
|
||
{
|
||
case CFA_REG_OFFSET:
|
||
cache->cfa = read_reg (next_frame, fs->cfa_reg);
|
||
if (fs->armcc_cfa_offsets_reversed)
|
||
cache->cfa -= fs->cfa_offset;
|
||
else
|
||
cache->cfa += fs->cfa_offset;
|
||
break;
|
||
|
||
case CFA_EXP:
|
||
cache->cfa =
|
||
execute_stack_op (fs->cfa_exp, fs->cfa_exp_len,
|
||
cache->addr_size, next_frame, 0);
|
||
break;
|
||
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("Unknown CFA rule."));
|
||
}
|
||
|
||
/* Initialize the register state. */
|
||
{
|
||
int regnum;
|
||
|
||
for (regnum = 0; regnum < num_regs; regnum++)
|
||
dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum], next_frame);
|
||
}
|
||
|
||
/* Go through the DWARF2 CFI generated table and save its register
|
||
location information in the cache. Note that we don't skip the
|
||
return address column; it's perfectly all right for it to
|
||
correspond to a real register. If it doesn't correspond to a
|
||
real register, or if we shouldn't treat it as such,
|
||
gdbarch_dwarf2_reg_to_regnum should be defined to return a number outside
|
||
the range [0, gdbarch_num_regs). */
|
||
{
|
||
int column; /* CFI speak for "register number". */
|
||
|
||
for (column = 0; column < fs->regs.num_regs; column++)
|
||
{
|
||
/* Use the GDB register number as the destination index. */
|
||
int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, column);
|
||
|
||
/* If there's no corresponding GDB register, ignore it. */
|
||
if (regnum < 0 || regnum >= num_regs)
|
||
continue;
|
||
|
||
/* NOTE: cagney/2003-09-05: CFI should specify the disposition
|
||
of all debug info registers. If it doesn't, complain (but
|
||
not too loudly). It turns out that GCC assumes that an
|
||
unspecified register implies "same value" when CFI (draft
|
||
7) specifies nothing at all. Such a register could equally
|
||
be interpreted as "undefined". Also note that this check
|
||
isn't sufficient; it only checks that all registers in the
|
||
range [0 .. max column] are specified, and won't detect
|
||
problems when a debug info register falls outside of the
|
||
table. We need a way of iterating through all the valid
|
||
DWARF2 register numbers. */
|
||
if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
|
||
{
|
||
if (cache->reg[regnum].how == DWARF2_FRAME_REG_UNSPECIFIED)
|
||
complaint (&symfile_complaints, _("\
|
||
incomplete CFI data; unspecified registers (e.g., %s) at 0x%s"),
|
||
gdbarch_register_name (gdbarch, regnum),
|
||
paddr_nz (fs->pc));
|
||
}
|
||
else
|
||
cache->reg[regnum] = fs->regs.reg[column];
|
||
}
|
||
}
|
||
|
||
/* Eliminate any DWARF2_FRAME_REG_RA rules, and save the information
|
||
we need for evaluating DWARF2_FRAME_REG_RA_OFFSET rules. */
|
||
{
|
||
int regnum;
|
||
|
||
for (regnum = 0; regnum < num_regs; regnum++)
|
||
{
|
||
if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA
|
||
|| cache->reg[regnum].how == DWARF2_FRAME_REG_RA_OFFSET)
|
||
{
|
||
struct dwarf2_frame_state_reg *retaddr_reg =
|
||
&fs->regs.reg[fs->retaddr_column];
|
||
|
||
/* It seems rather bizarre to specify an "empty" column as
|
||
the return adress column. However, this is exactly
|
||
what GCC does on some targets. It turns out that GCC
|
||
assumes that the return address can be found in the
|
||
register corresponding to the return address column.
|
||
Incidentally, that's how we should treat a return
|
||
address column specifying "same value" too. */
|
||
if (fs->retaddr_column < fs->regs.num_regs
|
||
&& retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
|
||
&& retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
|
||
{
|
||
if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
|
||
cache->reg[regnum] = *retaddr_reg;
|
||
else
|
||
cache->retaddr_reg = *retaddr_reg;
|
||
}
|
||
else
|
||
{
|
||
if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
|
||
{
|
||
cache->reg[regnum].loc.reg = fs->retaddr_column;
|
||
cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
|
||
}
|
||
else
|
||
{
|
||
cache->retaddr_reg.loc.reg = fs->retaddr_column;
|
||
cache->retaddr_reg.how = DWARF2_FRAME_REG_SAVED_REG;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
if (fs->retaddr_column < fs->regs.num_regs
|
||
&& fs->regs.reg[fs->retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
|
||
cache->undefined_retaddr = 1;
|
||
|
||
do_cleanups (old_chain);
|
||
|
||
*this_cache = cache;
|
||
return cache;
|
||
}
|
||
|
||
static void
|
||
dwarf2_frame_this_id (struct frame_info *next_frame, void **this_cache,
|
||
struct frame_id *this_id)
|
||
{
|
||
struct dwarf2_frame_cache *cache =
|
||
dwarf2_frame_cache (next_frame, this_cache);
|
||
|
||
if (cache->undefined_retaddr)
|
||
return;
|
||
|
||
(*this_id) = frame_id_build (cache->cfa,
|
||
frame_func_unwind (next_frame, NORMAL_FRAME));
|
||
}
|
||
|
||
static void
|
||
dwarf2_signal_frame_this_id (struct frame_info *next_frame, void **this_cache,
|
||
struct frame_id *this_id)
|
||
{
|
||
struct dwarf2_frame_cache *cache =
|
||
dwarf2_frame_cache (next_frame, this_cache);
|
||
|
||
if (cache->undefined_retaddr)
|
||
return;
|
||
|
||
(*this_id) = frame_id_build (cache->cfa,
|
||
frame_func_unwind (next_frame, SIGTRAMP_FRAME));
|
||
}
|
||
|
||
static void
|
||
dwarf2_frame_prev_register (struct frame_info *next_frame, void **this_cache,
|
||
int regnum, int *optimizedp,
|
||
enum lval_type *lvalp, CORE_ADDR *addrp,
|
||
int *realnump, gdb_byte *valuep)
|
||
{
|
||
struct gdbarch *gdbarch = get_frame_arch (next_frame);
|
||
struct dwarf2_frame_cache *cache =
|
||
dwarf2_frame_cache (next_frame, this_cache);
|
||
|
||
switch (cache->reg[regnum].how)
|
||
{
|
||
case DWARF2_FRAME_REG_UNDEFINED:
|
||
/* If CFI explicitly specified that the value isn't defined,
|
||
mark it as optimized away; the value isn't available. */
|
||
*optimizedp = 1;
|
||
*lvalp = not_lval;
|
||
*addrp = 0;
|
||
*realnump = -1;
|
||
if (valuep)
|
||
{
|
||
/* In some cases, for example %eflags on the i386, we have
|
||
to provide a sane value, even though this register wasn't
|
||
saved. Assume we can get it from NEXT_FRAME. */
|
||
frame_unwind_register (next_frame, regnum, valuep);
|
||
}
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_SAVED_OFFSET:
|
||
*optimizedp = 0;
|
||
*lvalp = lval_memory;
|
||
*addrp = cache->cfa + cache->reg[regnum].loc.offset;
|
||
*realnump = -1;
|
||
if (valuep)
|
||
{
|
||
/* Read the value in from memory. */
|
||
read_memory (*addrp, valuep, register_size (gdbarch, regnum));
|
||
}
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_SAVED_REG:
|
||
*optimizedp = 0;
|
||
*lvalp = lval_register;
|
||
*addrp = 0;
|
||
*realnump = gdbarch_dwarf2_reg_to_regnum
|
||
(gdbarch, cache->reg[regnum].loc.reg);
|
||
if (valuep)
|
||
frame_unwind_register (next_frame, (*realnump), valuep);
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_SAVED_EXP:
|
||
*optimizedp = 0;
|
||
*lvalp = lval_memory;
|
||
*addrp = execute_stack_op (cache->reg[regnum].loc.exp,
|
||
cache->reg[regnum].exp_len,
|
||
cache->addr_size, next_frame, cache->cfa);
|
||
*realnump = -1;
|
||
if (valuep)
|
||
{
|
||
/* Read the value in from memory. */
|
||
read_memory (*addrp, valuep, register_size (gdbarch, regnum));
|
||
}
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_SAVED_VAL_OFFSET:
|
||
*optimizedp = 0;
|
||
*lvalp = not_lval;
|
||
*addrp = 0;
|
||
*realnump = -1;
|
||
if (valuep)
|
||
store_unsigned_integer (valuep, register_size (gdbarch, regnum),
|
||
cache->cfa + cache->reg[regnum].loc.offset);
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_SAVED_VAL_EXP:
|
||
*optimizedp = 0;
|
||
*lvalp = not_lval;
|
||
*addrp = 0;
|
||
*realnump = -1;
|
||
if (valuep)
|
||
store_unsigned_integer (valuep, register_size (gdbarch, regnum),
|
||
execute_stack_op (cache->reg[regnum].loc.exp,
|
||
cache->reg[regnum].exp_len,
|
||
cache->addr_size, next_frame,
|
||
cache->cfa));
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_UNSPECIFIED:
|
||
/* GCC, in its infinite wisdom decided to not provide unwind
|
||
information for registers that are "same value". Since
|
||
DWARF2 (3 draft 7) doesn't define such behavior, said
|
||
registers are actually undefined (which is different to CFI
|
||
"undefined"). Code above issues a complaint about this.
|
||
Here just fudge the books, assume GCC, and that the value is
|
||
more inner on the stack. */
|
||
*optimizedp = 0;
|
||
*lvalp = lval_register;
|
||
*addrp = 0;
|
||
*realnump = regnum;
|
||
if (valuep)
|
||
frame_unwind_register (next_frame, (*realnump), valuep);
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_SAME_VALUE:
|
||
*optimizedp = 0;
|
||
*lvalp = lval_register;
|
||
*addrp = 0;
|
||
*realnump = regnum;
|
||
if (valuep)
|
||
frame_unwind_register (next_frame, (*realnump), valuep);
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_CFA:
|
||
*optimizedp = 0;
|
||
*lvalp = not_lval;
|
||
*addrp = 0;
|
||
*realnump = -1;
|
||
if (valuep)
|
||
pack_long (valuep, register_type (gdbarch, regnum), cache->cfa);
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_CFA_OFFSET:
|
||
*optimizedp = 0;
|
||
*lvalp = not_lval;
|
||
*addrp = 0;
|
||
*realnump = -1;
|
||
if (valuep)
|
||
pack_long (valuep, register_type (gdbarch, regnum),
|
||
cache->cfa + cache->reg[regnum].loc.offset);
|
||
break;
|
||
|
||
case DWARF2_FRAME_REG_RA_OFFSET:
|
||
*optimizedp = 0;
|
||
*lvalp = not_lval;
|
||
*addrp = 0;
|
||
*realnump = -1;
|
||
if (valuep)
|
||
{
|
||
CORE_ADDR pc = cache->reg[regnum].loc.offset;
|
||
|
||
regnum = gdbarch_dwarf2_reg_to_regnum
|
||
(gdbarch, cache->retaddr_reg.loc.reg);
|
||
pc += frame_unwind_register_unsigned (next_frame, regnum);
|
||
pack_long (valuep, register_type (gdbarch, regnum), pc);
|
||
}
|
||
break;
|
||
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("Unknown register rule."));
|
||
}
|
||
}
|
||
|
||
static const struct frame_unwind dwarf2_frame_unwind =
|
||
{
|
||
NORMAL_FRAME,
|
||
dwarf2_frame_this_id,
|
||
dwarf2_frame_prev_register
|
||
};
|
||
|
||
static const struct frame_unwind dwarf2_signal_frame_unwind =
|
||
{
|
||
SIGTRAMP_FRAME,
|
||
dwarf2_signal_frame_this_id,
|
||
dwarf2_frame_prev_register
|
||
};
|
||
|
||
const struct frame_unwind *
|
||
dwarf2_frame_sniffer (struct frame_info *next_frame)
|
||
{
|
||
/* Grab an address that is guarenteed to reside somewhere within the
|
||
function. frame_pc_unwind(), for a no-return next function, can
|
||
end up returning something past the end of this function's body.
|
||
If the frame we're sniffing for is a signal frame whose start
|
||
address is placed on the stack by the OS, its FDE must
|
||
extend one byte before its start address or we will miss it. */
|
||
CORE_ADDR block_addr = frame_unwind_address_in_block (next_frame,
|
||
NORMAL_FRAME);
|
||
struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr);
|
||
if (!fde)
|
||
return NULL;
|
||
|
||
/* On some targets, signal trampolines may have unwind information.
|
||
We need to recognize them so that we set the frame type
|
||
correctly. */
|
||
|
||
if (fde->cie->signal_frame
|
||
|| dwarf2_frame_signal_frame_p (get_frame_arch (next_frame),
|
||
next_frame))
|
||
return &dwarf2_signal_frame_unwind;
|
||
|
||
return &dwarf2_frame_unwind;
|
||
}
|
||
|
||
|
||
/* There is no explicitly defined relationship between the CFA and the
|
||
location of frame's local variables and arguments/parameters.
|
||
Therefore, frame base methods on this page should probably only be
|
||
used as a last resort, just to avoid printing total garbage as a
|
||
response to the "info frame" command. */
|
||
|
||
static CORE_ADDR
|
||
dwarf2_frame_base_address (struct frame_info *next_frame, void **this_cache)
|
||
{
|
||
struct dwarf2_frame_cache *cache =
|
||
dwarf2_frame_cache (next_frame, this_cache);
|
||
|
||
return cache->cfa;
|
||
}
|
||
|
||
static const struct frame_base dwarf2_frame_base =
|
||
{
|
||
&dwarf2_frame_unwind,
|
||
dwarf2_frame_base_address,
|
||
dwarf2_frame_base_address,
|
||
dwarf2_frame_base_address
|
||
};
|
||
|
||
const struct frame_base *
|
||
dwarf2_frame_base_sniffer (struct frame_info *next_frame)
|
||
{
|
||
CORE_ADDR block_addr = frame_unwind_address_in_block (next_frame,
|
||
NORMAL_FRAME);
|
||
if (dwarf2_frame_find_fde (&block_addr))
|
||
return &dwarf2_frame_base;
|
||
|
||
return NULL;
|
||
}
|
||
|
||
const struct objfile_data *dwarf2_frame_objfile_data;
|
||
|
||
static unsigned int
|
||
read_1_byte (bfd *abfd, gdb_byte *buf)
|
||
{
|
||
return bfd_get_8 (abfd, buf);
|
||
}
|
||
|
||
static unsigned int
|
||
read_4_bytes (bfd *abfd, gdb_byte *buf)
|
||
{
|
||
return bfd_get_32 (abfd, buf);
|
||
}
|
||
|
||
static ULONGEST
|
||
read_8_bytes (bfd *abfd, gdb_byte *buf)
|
||
{
|
||
return bfd_get_64 (abfd, buf);
|
||
}
|
||
|
||
static ULONGEST
|
||
read_unsigned_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
|
||
{
|
||
ULONGEST result;
|
||
unsigned int num_read;
|
||
int shift;
|
||
gdb_byte byte;
|
||
|
||
result = 0;
|
||
shift = 0;
|
||
num_read = 0;
|
||
|
||
do
|
||
{
|
||
byte = bfd_get_8 (abfd, (bfd_byte *) buf);
|
||
buf++;
|
||
num_read++;
|
||
result |= ((byte & 0x7f) << shift);
|
||
shift += 7;
|
||
}
|
||
while (byte & 0x80);
|
||
|
||
*bytes_read_ptr = num_read;
|
||
|
||
return result;
|
||
}
|
||
|
||
static LONGEST
|
||
read_signed_leb128 (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
|
||
{
|
||
LONGEST result;
|
||
int shift;
|
||
unsigned int num_read;
|
||
gdb_byte byte;
|
||
|
||
result = 0;
|
||
shift = 0;
|
||
num_read = 0;
|
||
|
||
do
|
||
{
|
||
byte = bfd_get_8 (abfd, (bfd_byte *) buf);
|
||
buf++;
|
||
num_read++;
|
||
result |= ((byte & 0x7f) << shift);
|
||
shift += 7;
|
||
}
|
||
while (byte & 0x80);
|
||
|
||
if (shift < 8 * sizeof (result) && (byte & 0x40))
|
||
result |= -(((LONGEST)1) << shift);
|
||
|
||
*bytes_read_ptr = num_read;
|
||
|
||
return result;
|
||
}
|
||
|
||
static ULONGEST
|
||
read_initial_length (bfd *abfd, gdb_byte *buf, unsigned int *bytes_read_ptr)
|
||
{
|
||
LONGEST result;
|
||
|
||
result = bfd_get_32 (abfd, buf);
|
||
if (result == 0xffffffff)
|
||
{
|
||
result = bfd_get_64 (abfd, buf + 4);
|
||
*bytes_read_ptr = 12;
|
||
}
|
||
else
|
||
*bytes_read_ptr = 4;
|
||
|
||
return result;
|
||
}
|
||
|
||
|
||
/* Pointer encoding helper functions. */
|
||
|
||
/* GCC supports exception handling based on DWARF2 CFI. However, for
|
||
technical reasons, it encodes addresses in its FDE's in a different
|
||
way. Several "pointer encodings" are supported. The encoding
|
||
that's used for a particular FDE is determined by the 'R'
|
||
augmentation in the associated CIE. The argument of this
|
||
augmentation is a single byte.
|
||
|
||
The address can be encoded as 2 bytes, 4 bytes, 8 bytes, or as a
|
||
LEB128. This is encoded in bits 0, 1 and 2. Bit 3 encodes whether
|
||
the address is signed or unsigned. Bits 4, 5 and 6 encode how the
|
||
address should be interpreted (absolute, relative to the current
|
||
position in the FDE, ...). Bit 7, indicates that the address
|
||
should be dereferenced. */
|
||
|
||
static gdb_byte
|
||
encoding_for_size (unsigned int size)
|
||
{
|
||
switch (size)
|
||
{
|
||
case 2:
|
||
return DW_EH_PE_udata2;
|
||
case 4:
|
||
return DW_EH_PE_udata4;
|
||
case 8:
|
||
return DW_EH_PE_udata8;
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("Unsupported address size"));
|
||
}
|
||
}
|
||
|
||
static CORE_ADDR
|
||
read_encoded_value (struct comp_unit *unit, gdb_byte encoding,
|
||
int ptr_len, gdb_byte *buf, unsigned int *bytes_read_ptr,
|
||
CORE_ADDR func_base)
|
||
{
|
||
ptrdiff_t offset;
|
||
CORE_ADDR base;
|
||
|
||
/* GCC currently doesn't generate DW_EH_PE_indirect encodings for
|
||
FDE's. */
|
||
if (encoding & DW_EH_PE_indirect)
|
||
internal_error (__FILE__, __LINE__,
|
||
_("Unsupported encoding: DW_EH_PE_indirect"));
|
||
|
||
*bytes_read_ptr = 0;
|
||
|
||
switch (encoding & 0x70)
|
||
{
|
||
case DW_EH_PE_absptr:
|
||
base = 0;
|
||
break;
|
||
case DW_EH_PE_pcrel:
|
||
base = bfd_get_section_vma (unit->abfd, unit->dwarf_frame_section);
|
||
base += (buf - unit->dwarf_frame_buffer);
|
||
break;
|
||
case DW_EH_PE_datarel:
|
||
base = unit->dbase;
|
||
break;
|
||
case DW_EH_PE_textrel:
|
||
base = unit->tbase;
|
||
break;
|
||
case DW_EH_PE_funcrel:
|
||
base = func_base;
|
||
break;
|
||
case DW_EH_PE_aligned:
|
||
base = 0;
|
||
offset = buf - unit->dwarf_frame_buffer;
|
||
if ((offset % ptr_len) != 0)
|
||
{
|
||
*bytes_read_ptr = ptr_len - (offset % ptr_len);
|
||
buf += *bytes_read_ptr;
|
||
}
|
||
break;
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding"));
|
||
}
|
||
|
||
if ((encoding & 0x07) == 0x00)
|
||
{
|
||
encoding |= encoding_for_size (ptr_len);
|
||
if (bfd_get_sign_extend_vma (unit->abfd))
|
||
encoding |= DW_EH_PE_signed;
|
||
}
|
||
|
||
switch (encoding & 0x0f)
|
||
{
|
||
case DW_EH_PE_uleb128:
|
||
{
|
||
ULONGEST value;
|
||
gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
|
||
*bytes_read_ptr += read_uleb128 (buf, end_buf, &value) - buf;
|
||
return base + value;
|
||
}
|
||
case DW_EH_PE_udata2:
|
||
*bytes_read_ptr += 2;
|
||
return (base + bfd_get_16 (unit->abfd, (bfd_byte *) buf));
|
||
case DW_EH_PE_udata4:
|
||
*bytes_read_ptr += 4;
|
||
return (base + bfd_get_32 (unit->abfd, (bfd_byte *) buf));
|
||
case DW_EH_PE_udata8:
|
||
*bytes_read_ptr += 8;
|
||
return (base + bfd_get_64 (unit->abfd, (bfd_byte *) buf));
|
||
case DW_EH_PE_sleb128:
|
||
{
|
||
LONGEST value;
|
||
gdb_byte *end_buf = buf + (sizeof (value) + 1) * 8 / 7;
|
||
*bytes_read_ptr += read_sleb128 (buf, end_buf, &value) - buf;
|
||
return base + value;
|
||
}
|
||
case DW_EH_PE_sdata2:
|
||
*bytes_read_ptr += 2;
|
||
return (base + bfd_get_signed_16 (unit->abfd, (bfd_byte *) buf));
|
||
case DW_EH_PE_sdata4:
|
||
*bytes_read_ptr += 4;
|
||
return (base + bfd_get_signed_32 (unit->abfd, (bfd_byte *) buf));
|
||
case DW_EH_PE_sdata8:
|
||
*bytes_read_ptr += 8;
|
||
return (base + bfd_get_signed_64 (unit->abfd, (bfd_byte *) buf));
|
||
default:
|
||
internal_error (__FILE__, __LINE__, _("Invalid or unsupported encoding"));
|
||
}
|
||
}
|
||
|
||
|
||
/* GCC uses a single CIE for all FDEs in a .debug_frame section.
|
||
That's why we use a simple linked list here. */
|
||
|
||
static struct dwarf2_cie *
|
||
find_cie (struct comp_unit *unit, ULONGEST cie_pointer)
|
||
{
|
||
struct dwarf2_cie *cie = unit->cie;
|
||
|
||
while (cie)
|
||
{
|
||
if (cie->cie_pointer == cie_pointer)
|
||
return cie;
|
||
|
||
cie = cie->next;
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static void
|
||
add_cie (struct comp_unit *unit, struct dwarf2_cie *cie)
|
||
{
|
||
cie->next = unit->cie;
|
||
unit->cie = cie;
|
||
cie->unit = unit;
|
||
}
|
||
|
||
/* Find the FDE for *PC. Return a pointer to the FDE, and store the
|
||
inital location associated with it into *PC. */
|
||
|
||
static struct dwarf2_fde *
|
||
dwarf2_frame_find_fde (CORE_ADDR *pc)
|
||
{
|
||
struct objfile *objfile;
|
||
|
||
ALL_OBJFILES (objfile)
|
||
{
|
||
struct dwarf2_fde *fde;
|
||
CORE_ADDR offset;
|
||
|
||
fde = objfile_data (objfile, dwarf2_frame_objfile_data);
|
||
if (fde == NULL)
|
||
continue;
|
||
|
||
gdb_assert (objfile->section_offsets);
|
||
offset = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile));
|
||
|
||
while (fde)
|
||
{
|
||
if (*pc >= fde->initial_location + offset
|
||
&& *pc < fde->initial_location + offset + fde->address_range)
|
||
{
|
||
*pc = fde->initial_location + offset;
|
||
return fde;
|
||
}
|
||
|
||
fde = fde->next;
|
||
}
|
||
}
|
||
|
||
return NULL;
|
||
}
|
||
|
||
static void
|
||
add_fde (struct comp_unit *unit, struct dwarf2_fde *fde)
|
||
{
|
||
fde->next = objfile_data (unit->objfile, dwarf2_frame_objfile_data);
|
||
set_objfile_data (unit->objfile, dwarf2_frame_objfile_data, fde);
|
||
}
|
||
|
||
#ifdef CC_HAS_LONG_LONG
|
||
#define DW64_CIE_ID 0xffffffffffffffffULL
|
||
#else
|
||
#define DW64_CIE_ID ~0
|
||
#endif
|
||
|
||
static gdb_byte *decode_frame_entry (struct comp_unit *unit, gdb_byte *start,
|
||
int eh_frame_p);
|
||
|
||
/* Decode the next CIE or FDE. Return NULL if invalid input, otherwise
|
||
the next byte to be processed. */
|
||
static gdb_byte *
|
||
decode_frame_entry_1 (struct comp_unit *unit, gdb_byte *start, int eh_frame_p)
|
||
{
|
||
struct gdbarch *gdbarch = get_objfile_arch (unit->objfile);
|
||
gdb_byte *buf, *end;
|
||
LONGEST length;
|
||
unsigned int bytes_read;
|
||
int dwarf64_p;
|
||
ULONGEST cie_id;
|
||
ULONGEST cie_pointer;
|
||
|
||
buf = start;
|
||
length = read_initial_length (unit->abfd, buf, &bytes_read);
|
||
buf += bytes_read;
|
||
end = buf + length;
|
||
|
||
/* Are we still within the section? */
|
||
if (end > unit->dwarf_frame_buffer + unit->dwarf_frame_size)
|
||
return NULL;
|
||
|
||
if (length == 0)
|
||
return end;
|
||
|
||
/* Distinguish between 32 and 64-bit encoded frame info. */
|
||
dwarf64_p = (bytes_read == 12);
|
||
|
||
/* In a .eh_frame section, zero is used to distinguish CIEs from FDEs. */
|
||
if (eh_frame_p)
|
||
cie_id = 0;
|
||
else if (dwarf64_p)
|
||
cie_id = DW64_CIE_ID;
|
||
else
|
||
cie_id = DW_CIE_ID;
|
||
|
||
if (dwarf64_p)
|
||
{
|
||
cie_pointer = read_8_bytes (unit->abfd, buf);
|
||
buf += 8;
|
||
}
|
||
else
|
||
{
|
||
cie_pointer = read_4_bytes (unit->abfd, buf);
|
||
buf += 4;
|
||
}
|
||
|
||
if (cie_pointer == cie_id)
|
||
{
|
||
/* This is a CIE. */
|
||
struct dwarf2_cie *cie;
|
||
char *augmentation;
|
||
unsigned int cie_version;
|
||
|
||
/* Record the offset into the .debug_frame section of this CIE. */
|
||
cie_pointer = start - unit->dwarf_frame_buffer;
|
||
|
||
/* Check whether we've already read it. */
|
||
if (find_cie (unit, cie_pointer))
|
||
return end;
|
||
|
||
cie = (struct dwarf2_cie *)
|
||
obstack_alloc (&unit->objfile->objfile_obstack,
|
||
sizeof (struct dwarf2_cie));
|
||
cie->initial_instructions = NULL;
|
||
cie->cie_pointer = cie_pointer;
|
||
|
||
/* The encoding for FDE's in a normal .debug_frame section
|
||
depends on the target address size. */
|
||
cie->encoding = DW_EH_PE_absptr;
|
||
|
||
/* The target address size. For .eh_frame FDEs this is considered
|
||
equal to the size of a target pointer. For .dwarf_frame FDEs,
|
||
this is supposed to be the target address size from the associated
|
||
CU header. FIXME: We do not have a good way to determine the
|
||
latter. Always use the target pointer size for now. */
|
||
cie->addr_size = gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
|
||
|
||
/* We'll determine the final value later, but we need to
|
||
initialize it conservatively. */
|
||
cie->signal_frame = 0;
|
||
|
||
/* Check version number. */
|
||
cie_version = read_1_byte (unit->abfd, buf);
|
||
if (cie_version != 1 && cie_version != 3)
|
||
return NULL;
|
||
cie->version = cie_version;
|
||
buf += 1;
|
||
|
||
/* Interpret the interesting bits of the augmentation. */
|
||
cie->augmentation = augmentation = (char *) buf;
|
||
buf += (strlen (augmentation) + 1);
|
||
|
||
/* Ignore armcc augmentations. We only use them for quirks,
|
||
and that doesn't happen until later. */
|
||
if (strncmp (augmentation, "armcc", 5) == 0)
|
||
augmentation += strlen (augmentation);
|
||
|
||
/* The GCC 2.x "eh" augmentation has a pointer immediately
|
||
following the augmentation string, so it must be handled
|
||
first. */
|
||
if (augmentation[0] == 'e' && augmentation[1] == 'h')
|
||
{
|
||
/* Skip. */
|
||
buf += gdbarch_ptr_bit (gdbarch) / TARGET_CHAR_BIT;
|
||
augmentation += 2;
|
||
}
|
||
|
||
cie->code_alignment_factor =
|
||
read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
|
||
buf += bytes_read;
|
||
|
||
cie->data_alignment_factor =
|
||
read_signed_leb128 (unit->abfd, buf, &bytes_read);
|
||
buf += bytes_read;
|
||
|
||
if (cie_version == 1)
|
||
{
|
||
cie->return_address_register = read_1_byte (unit->abfd, buf);
|
||
bytes_read = 1;
|
||
}
|
||
else
|
||
cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf,
|
||
&bytes_read);
|
||
cie->return_address_register
|
||
= dwarf2_frame_adjust_regnum (gdbarch,
|
||
cie->return_address_register,
|
||
eh_frame_p);
|
||
|
||
buf += bytes_read;
|
||
|
||
cie->saw_z_augmentation = (*augmentation == 'z');
|
||
if (cie->saw_z_augmentation)
|
||
{
|
||
ULONGEST length;
|
||
|
||
length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
|
||
buf += bytes_read;
|
||
if (buf > end)
|
||
return NULL;
|
||
cie->initial_instructions = buf + length;
|
||
augmentation++;
|
||
}
|
||
|
||
while (*augmentation)
|
||
{
|
||
/* "L" indicates a byte showing how the LSDA pointer is encoded. */
|
||
if (*augmentation == 'L')
|
||
{
|
||
/* Skip. */
|
||
buf++;
|
||
augmentation++;
|
||
}
|
||
|
||
/* "R" indicates a byte indicating how FDE addresses are encoded. */
|
||
else if (*augmentation == 'R')
|
||
{
|
||
cie->encoding = *buf++;
|
||
augmentation++;
|
||
}
|
||
|
||
/* "P" indicates a personality routine in the CIE augmentation. */
|
||
else if (*augmentation == 'P')
|
||
{
|
||
/* Skip. Avoid indirection since we throw away the result. */
|
||
gdb_byte encoding = (*buf++) & ~DW_EH_PE_indirect;
|
||
read_encoded_value (unit, encoding, cie->addr_size,
|
||
buf, &bytes_read, 0);
|
||
buf += bytes_read;
|
||
augmentation++;
|
||
}
|
||
|
||
/* "S" indicates a signal frame, such that the return
|
||
address must not be decremented to locate the call frame
|
||
info for the previous frame; it might even be the first
|
||
instruction of a function, so decrementing it would take
|
||
us to a different function. */
|
||
else if (*augmentation == 'S')
|
||
{
|
||
cie->signal_frame = 1;
|
||
augmentation++;
|
||
}
|
||
|
||
/* Otherwise we have an unknown augmentation. Assume that either
|
||
there is no augmentation data, or we saw a 'z' prefix. */
|
||
else
|
||
{
|
||
if (cie->initial_instructions)
|
||
buf = cie->initial_instructions;
|
||
break;
|
||
}
|
||
}
|
||
|
||
cie->initial_instructions = buf;
|
||
cie->end = end;
|
||
|
||
add_cie (unit, cie);
|
||
}
|
||
else
|
||
{
|
||
/* This is a FDE. */
|
||
struct dwarf2_fde *fde;
|
||
|
||
/* In an .eh_frame section, the CIE pointer is the delta between the
|
||
address within the FDE where the CIE pointer is stored and the
|
||
address of the CIE. Convert it to an offset into the .eh_frame
|
||
section. */
|
||
if (eh_frame_p)
|
||
{
|
||
cie_pointer = buf - unit->dwarf_frame_buffer - cie_pointer;
|
||
cie_pointer -= (dwarf64_p ? 8 : 4);
|
||
}
|
||
|
||
/* In either case, validate the result is still within the section. */
|
||
if (cie_pointer >= unit->dwarf_frame_size)
|
||
return NULL;
|
||
|
||
fde = (struct dwarf2_fde *)
|
||
obstack_alloc (&unit->objfile->objfile_obstack,
|
||
sizeof (struct dwarf2_fde));
|
||
fde->cie = find_cie (unit, cie_pointer);
|
||
if (fde->cie == NULL)
|
||
{
|
||
decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer,
|
||
eh_frame_p);
|
||
fde->cie = find_cie (unit, cie_pointer);
|
||
}
|
||
|
||
gdb_assert (fde->cie != NULL);
|
||
|
||
fde->initial_location =
|
||
read_encoded_value (unit, fde->cie->encoding, fde->cie->addr_size,
|
||
buf, &bytes_read, 0);
|
||
buf += bytes_read;
|
||
|
||
fde->address_range =
|
||
read_encoded_value (unit, fde->cie->encoding & 0x0f,
|
||
fde->cie->addr_size, buf, &bytes_read, 0);
|
||
buf += bytes_read;
|
||
|
||
/* A 'z' augmentation in the CIE implies the presence of an
|
||
augmentation field in the FDE as well. The only thing known
|
||
to be in here at present is the LSDA entry for EH. So we
|
||
can skip the whole thing. */
|
||
if (fde->cie->saw_z_augmentation)
|
||
{
|
||
ULONGEST length;
|
||
|
||
length = read_unsigned_leb128 (unit->abfd, buf, &bytes_read);
|
||
buf += bytes_read + length;
|
||
if (buf > end)
|
||
return NULL;
|
||
}
|
||
|
||
fde->instructions = buf;
|
||
fde->end = end;
|
||
|
||
fde->eh_frame_p = eh_frame_p;
|
||
|
||
add_fde (unit, fde);
|
||
}
|
||
|
||
return end;
|
||
}
|
||
|
||
/* Read a CIE or FDE in BUF and decode it. */
|
||
static gdb_byte *
|
||
decode_frame_entry (struct comp_unit *unit, gdb_byte *start, int eh_frame_p)
|
||
{
|
||
enum { NONE, ALIGN4, ALIGN8, FAIL } workaround = NONE;
|
||
gdb_byte *ret;
|
||
const char *msg;
|
||
ptrdiff_t start_offset;
|
||
|
||
while (1)
|
||
{
|
||
ret = decode_frame_entry_1 (unit, start, eh_frame_p);
|
||
if (ret != NULL)
|
||
break;
|
||
|
||
/* We have corrupt input data of some form. */
|
||
|
||
/* ??? Try, weakly, to work around compiler/assembler/linker bugs
|
||
and mismatches wrt padding and alignment of debug sections. */
|
||
/* Note that there is no requirement in the standard for any
|
||
alignment at all in the frame unwind sections. Testing for
|
||
alignment before trying to interpret data would be incorrect.
|
||
|
||
However, GCC traditionally arranged for frame sections to be
|
||
sized such that the FDE length and CIE fields happen to be
|
||
aligned (in theory, for performance). This, unfortunately,
|
||
was done with .align directives, which had the side effect of
|
||
forcing the section to be aligned by the linker.
|
||
|
||
This becomes a problem when you have some other producer that
|
||
creates frame sections that are not as strictly aligned. That
|
||
produces a hole in the frame info that gets filled by the
|
||
linker with zeros.
|
||
|
||
The GCC behaviour is arguably a bug, but it's effectively now
|
||
part of the ABI, so we're now stuck with it, at least at the
|
||
object file level. A smart linker may decide, in the process
|
||
of compressing duplicate CIE information, that it can rewrite
|
||
the entire output section without this extra padding. */
|
||
|
||
start_offset = start - unit->dwarf_frame_buffer;
|
||
if (workaround < ALIGN4 && (start_offset & 3) != 0)
|
||
{
|
||
start += 4 - (start_offset & 3);
|
||
workaround = ALIGN4;
|
||
continue;
|
||
}
|
||
if (workaround < ALIGN8 && (start_offset & 7) != 0)
|
||
{
|
||
start += 8 - (start_offset & 7);
|
||
workaround = ALIGN8;
|
||
continue;
|
||
}
|
||
|
||
/* Nothing left to try. Arrange to return as if we've consumed
|
||
the entire input section. Hopefully we'll get valid info from
|
||
the other of .debug_frame/.eh_frame. */
|
||
workaround = FAIL;
|
||
ret = unit->dwarf_frame_buffer + unit->dwarf_frame_size;
|
||
break;
|
||
}
|
||
|
||
switch (workaround)
|
||
{
|
||
case NONE:
|
||
break;
|
||
|
||
case ALIGN4:
|
||
complaint (&symfile_complaints,
|
||
_("Corrupt data in %s:%s; align 4 workaround apparently succeeded"),
|
||
unit->dwarf_frame_section->owner->filename,
|
||
unit->dwarf_frame_section->name);
|
||
break;
|
||
|
||
case ALIGN8:
|
||
complaint (&symfile_complaints,
|
||
_("Corrupt data in %s:%s; align 8 workaround apparently succeeded"),
|
||
unit->dwarf_frame_section->owner->filename,
|
||
unit->dwarf_frame_section->name);
|
||
break;
|
||
|
||
default:
|
||
complaint (&symfile_complaints,
|
||
_("Corrupt data in %s:%s"),
|
||
unit->dwarf_frame_section->owner->filename,
|
||
unit->dwarf_frame_section->name);
|
||
break;
|
||
}
|
||
|
||
return ret;
|
||
}
|
||
|
||
|
||
/* FIXME: kettenis/20030504: This still needs to be integrated with
|
||
dwarf2read.c in a better way. */
|
||
|
||
/* Imported from dwarf2read.c. */
|
||
extern asection *dwarf_frame_section;
|
||
extern asection *dwarf_eh_frame_section;
|
||
|
||
/* Imported from dwarf2read.c. */
|
||
extern gdb_byte *dwarf2_read_section (struct objfile *objfile, asection *sectp);
|
||
|
||
void
|
||
dwarf2_build_frame_info (struct objfile *objfile)
|
||
{
|
||
struct comp_unit *unit;
|
||
gdb_byte *frame_ptr;
|
||
|
||
/* Build a minimal decoding of the DWARF2 compilation unit. */
|
||
unit = (struct comp_unit *) obstack_alloc (&objfile->objfile_obstack,
|
||
sizeof (struct comp_unit));
|
||
unit->abfd = objfile->obfd;
|
||
unit->objfile = objfile;
|
||
unit->dbase = 0;
|
||
unit->tbase = 0;
|
||
|
||
/* First add the information from the .eh_frame section. That way,
|
||
the FDEs from that section are searched last. */
|
||
if (dwarf_eh_frame_section)
|
||
{
|
||
asection *got, *txt;
|
||
|
||
unit->cie = NULL;
|
||
unit->dwarf_frame_buffer = dwarf2_read_section (objfile,
|
||
dwarf_eh_frame_section);
|
||
|
||
unit->dwarf_frame_size = bfd_get_section_size (dwarf_eh_frame_section);
|
||
unit->dwarf_frame_section = dwarf_eh_frame_section;
|
||
|
||
/* FIXME: kettenis/20030602: This is the DW_EH_PE_datarel base
|
||
that is used for the i386/amd64 target, which currently is
|
||
the only target in GCC that supports/uses the
|
||
DW_EH_PE_datarel encoding. */
|
||
got = bfd_get_section_by_name (unit->abfd, ".got");
|
||
if (got)
|
||
unit->dbase = got->vma;
|
||
|
||
/* GCC emits the DW_EH_PE_textrel encoding type on sh and ia64
|
||
so far. */
|
||
txt = bfd_get_section_by_name (unit->abfd, ".text");
|
||
if (txt)
|
||
unit->tbase = txt->vma;
|
||
|
||
frame_ptr = unit->dwarf_frame_buffer;
|
||
while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
|
||
frame_ptr = decode_frame_entry (unit, frame_ptr, 1);
|
||
}
|
||
|
||
if (dwarf_frame_section)
|
||
{
|
||
unit->cie = NULL;
|
||
unit->dwarf_frame_buffer = dwarf2_read_section (objfile,
|
||
dwarf_frame_section);
|
||
unit->dwarf_frame_size = bfd_get_section_size (dwarf_frame_section);
|
||
unit->dwarf_frame_section = dwarf_frame_section;
|
||
|
||
frame_ptr = unit->dwarf_frame_buffer;
|
||
while (frame_ptr < unit->dwarf_frame_buffer + unit->dwarf_frame_size)
|
||
frame_ptr = decode_frame_entry (unit, frame_ptr, 0);
|
||
}
|
||
}
|
||
|
||
/* Provide a prototype to silence -Wmissing-prototypes. */
|
||
void _initialize_dwarf2_frame (void);
|
||
|
||
void
|
||
_initialize_dwarf2_frame (void)
|
||
{
|
||
dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
|
||
dwarf2_frame_objfile_data = register_objfile_data ();
|
||
}
|