| /* Frame unwinder for frames with DWARF Call Frame Information. |
| |
| Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation, Inc. |
| |
| Contributed by Mark Kettenis. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| #include "dwarf2expr.h" |
| #include "elf/dwarf2.h" |
| #include "frame.h" |
| #include "frame-base.h" |
| #include "frame-unwind.h" |
| #include "gdbcore.h" |
| #include "gdbtypes.h" |
| #include "symtab.h" |
| #include "objfiles.h" |
| #include "regcache.h" |
| #include "value.h" |
| |
| #include "gdb_assert.h" |
| #include "gdb_string.h" |
| |
| #include "complaints.h" |
| #include "dwarf2-frame.h" |
| |
| struct comp_unit; |
| |
| /* Call Frame Information (CFI). */ |
| |
| /* Common Information Entry (CIE). */ |
| |
| struct dwarf2_cie |
| { |
| /* Computation Unit for this CIE. */ |
| struct comp_unit *unit; |
| |
| /* Offset into the .debug_frame section where this CIE was found. |
| Used to identify this CIE. */ |
| ULONGEST cie_pointer; |
| |
| /* Constant that is factored out of all advance location |
| instructions. */ |
| ULONGEST code_alignment_factor; |
| |
| /* Constants that is factored out of all offset instructions. */ |
| LONGEST data_alignment_factor; |
| |
| /* Return address column. */ |
| ULONGEST return_address_register; |
| |
| /* Instruction sequence to initialize a register set. */ |
| gdb_byte *initial_instructions; |
| gdb_byte *end; |
| |
| /* Saved augmentation, in case it's needed later. */ |
| char *augmentation; |
| |
| /* Encoding of addresses. */ |
| gdb_byte encoding; |
| |
| /* Target address size in bytes. */ |
| int addr_size; |
| |
| /* True if a 'z' augmentation existed. */ |
| unsigned char saw_z_augmentation; |
| |
| /* True if an 'S' augmentation existed. */ |
| unsigned char signal_frame; |
| |
| /* The version recorded in the CIE. */ |
| unsigned char version; |
| |
| struct dwarf2_cie *next; |
| }; |
| |
| /* Frame Description Entry (FDE). */ |
| |
| struct dwarf2_fde |
| { |
| /* CIE for this FDE. */ |
| struct dwarf2_cie *cie; |
| |
| /* First location associated with this FDE. */ |
| CORE_ADDR initial_location; |
| |
| /* Number of bytes of program instructions described by this FDE. */ |
| CORE_ADDR address_range; |
| |
| /* Instruction sequence. */ |
| gdb_byte *instructions; |
| gdb_byte *end; |
| |
| /* True if this FDE is read from a .eh_frame instead of a .debug_frame |
| section. */ |
| unsigned char eh_frame_p; |
| |
| struct dwarf2_fde *next; |
| }; |
| |
| /* A minimal decoding of DWARF2 compilation units. We only decode |
| what's needed to get to the call frame information. */ |
| |
| struct comp_unit |
| { |
| /* Keep the bfd convenient. */ |
| bfd *abfd; |
| |
| struct objfile *objfile; |
| |
| /* Linked list of CIEs for this object. */ |
| struct dwarf2_cie *cie; |
| |
| /* Pointer to the .debug_frame section loaded into memory. */ |
| gdb_byte *dwarf_frame_buffer; |
| |
| /* Length of the loaded .debug_frame section. */ |
| unsigned long dwarf_frame_size; |
| |
| /* Pointer to the .debug_frame section. */ |
| asection *dwarf_frame_section; |
| |
| /* Base for DW_EH_PE_datarel encodings. */ |
| bfd_vma dbase; |
| |
| /* Base for DW_EH_PE_textrel encodings. */ |
| bfd_vma tbase; |
| }; |
| |
| static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc); |
| |
| static int dwarf2_frame_adjust_regnum (struct gdbarch *gdbarch, int regnum, |
| int eh_frame_p); |
| |
| 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); |
| |
| |
| /* Structure describing a frame state. */ |
| |
| struct dwarf2_frame_state |
| { |
| /* Each register save state can be described in terms of a CFA slot, |
| another register, or a location expression. */ |
| struct dwarf2_frame_state_reg_info |
| { |
| struct dwarf2_frame_state_reg *reg; |
| int num_regs; |
| |
| /* Used to implement DW_CFA_remember_state. */ |
| struct dwarf2_frame_state_reg_info *prev; |
| } regs; |
| |
| LONGEST cfa_offset; |
| ULONGEST cfa_reg; |
| gdb_byte *cfa_exp; |
| enum { |
| CFA_UNSET, |
| CFA_REG_OFFSET, |
| CFA_EXP |
| } cfa_how; |
| |
| /* The PC described by the current frame state. */ |
| CORE_ADDR pc; |
| |
| /* Initial register set from the CIE. |
| Used to implement DW_CFA_restore. */ |
| struct dwarf2_frame_state_reg_info initial; |
| |
| /* The information we care about from the CIE. */ |
| LONGEST data_align; |
| ULONGEST code_align; |
| ULONGEST retaddr_column; |
| |
| /* Flags for known producer quirks. */ |
| |
| /* The ARM compilers, in DWARF2 mode, assume that DW_CFA_def_cfa |
| and DW_CFA_def_cfa_offset takes a factored offset. */ |
| int armcc_cfa_offsets_sf; |
| |
| /* The ARM compilers, in DWARF2 or DWARF3 mode, may assume that |
| the CFA is defined as REG - OFFSET rather than REG + OFFSET. */ |
| int armcc_cfa_offsets_reversed; |
| }; |
| |
| /* Store the length the expression for the CFA in the `cfa_reg' field, |
| which is unused in that case. */ |
| #define cfa_exp_len cfa_reg |
| |
| /* Assert that the register set RS is large enough to store gdbarch_num_regs |
| columns. If necessary, enlarge the register set. */ |
| |
| static void |
| dwarf2_frame_state_alloc_regs (struct dwarf2_frame_state_reg_info *rs, |
| int num_regs) |
| { |
| size_t size = sizeof (struct dwarf2_frame_state_reg); |
| |
| if (num_regs <= rs->num_regs) |
| return; |
| |
| rs->reg = (struct dwarf2_frame_state_reg *) |
| xrealloc (rs->reg, num_regs * size); |
| |
| /* Initialize newly allocated registers. */ |
| memset (rs->reg + rs->num_regs, 0, (num_regs - rs->num_regs) * size); |
| rs->num_regs = num_regs; |
| } |
| |
| /* Copy the register columns in register set RS into newly allocated |
| memory and return a pointer to this newly created copy. */ |
| |
| static struct dwarf2_frame_state_reg * |
| dwarf2_frame_state_copy_regs (struct dwarf2_frame_state_reg_info *rs) |
| { |
| size_t size = rs->num_regs * sizeof (struct dwarf2_frame_state_reg); |
| struct dwarf2_frame_state_reg *reg; |
| |
| reg = (struct dwarf2_frame_state_reg *) xmalloc (size); |
| memcpy (reg, rs->reg, size); |
| |
| return reg; |
| } |
| |
| /* Release the memory allocated to register set RS. */ |
| |
| static void |
| dwarf2_frame_state_free_regs (struct dwarf2_frame_state_reg_info *rs) |
| { |
| if (rs) |
| { |
| dwarf2_frame_state_free_regs (rs->prev); |
| |
| xfree (rs->reg); |
| xfree (rs); |
| } |
| } |
| |
| /* Release the memory allocated to the frame state FS. */ |
| |
| static void |
| dwarf2_frame_state_free (void *p) |
| { |
| struct dwarf2_frame_state *fs = p; |
| |
| dwarf2_frame_state_free_regs (fs->initial.prev); |
| dwarf2_frame_state_free_regs (fs->regs.prev); |
| xfree (fs->initial.reg); |
| xfree (fs->regs.reg); |
| xfree (fs); |
| } |
| |
| |
| /* Helper functions for execute_stack_op. */ |
| |
| static CORE_ADDR |
| read_reg (void *baton, int reg) |
| { |
| struct frame_info *this_frame = (struct frame_info *) baton; |
| struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| int regnum; |
| gdb_byte *buf; |
| |
| regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg); |
| |
| buf = alloca (register_size (gdbarch, regnum)); |
| get_frame_register (this_frame, regnum, buf); |
| |
| /* Convert the register to an integer. This returns a LONGEST |
| rather than a CORE_ADDR, but unpack_pointer does the same thing |
| under the covers, and this makes more sense for non-pointer |
| registers. Maybe read_reg and the associated interfaces should |
| deal with "struct value" instead of CORE_ADDR. */ |
| return unpack_long (register_type (gdbarch, regnum), buf); |
| } |
| |
| static void |
| read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len) |
| { |
| read_memory (addr, buf, len); |
| } |
| |
| static void |
| no_get_frame_base (void *baton, gdb_byte **start, size_t *length) |
| { |
| internal_error (__FILE__, __LINE__, |
| _("Support for DW_OP_fbreg is unimplemented")); |
| } |
| |
| static CORE_ADDR |
| no_get_tls_address (void *baton, CORE_ADDR offset) |
| { |
| internal_error (__FILE__, __LINE__, |
| _("Support for DW_OP_GNU_push_tls_address is unimplemented")); |
| } |
| |
| /* Execute the required actions for both the DW_CFA_restore and |
| DW_CFA_restore_extended instructions. */ |
| static void |
| dwarf2_restore_rule (struct gdbarch *gdbarch, ULONGEST reg_num, |
| struct dwarf2_frame_state *fs, int eh_frame_p) |
| { |
| ULONGEST reg; |
| |
| gdb_assert (fs->initial.reg); |
| reg = dwarf2_frame_adjust_regnum (gdbarch, reg_num, eh_frame_p); |
| dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1); |
| |
| /* Check if this register was explicitly initialized in the |
| CIE initial instructions. If not, default the rule to |
| UNSPECIFIED. */ |
| if (reg < fs->initial.num_regs) |
| fs->regs.reg[reg] = fs->initial.reg[reg]; |
| else |
| fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNSPECIFIED; |
| |
| if (fs->regs.reg[reg].how == DWARF2_FRAME_REG_UNSPECIFIED) |
| complaint (&symfile_complaints, _("\ |
| incomplete CFI data; DW_CFA_restore unspecified\n\ |
| register %s (#%d) at 0x%s"), |
| gdbarch_register_name |
| (gdbarch, gdbarch_dwarf2_reg_to_regnum (gdbarch, reg)), |
| gdbarch_dwarf2_reg_to_regnum (gdbarch, reg), |
| paddr (fs->pc)); |
| } |
| |
| static CORE_ADDR |
| execute_stack_op (gdb_byte *exp, ULONGEST len, int addr_size, |
| struct frame_info *this_frame, CORE_ADDR initial) |
| { |
| struct dwarf_expr_context *ctx; |
| CORE_ADDR result; |
| |
| ctx = new_dwarf_expr_context (); |
| ctx->addr_size = addr_size; |
| ctx->baton = this_frame; |
| ctx->read_reg = read_reg; |
| ctx->read_mem = read_mem; |
| ctx->get_frame_base = no_get_frame_base; |
| ctx->get_tls_address = no_get_tls_address; |
| |
| dwarf_expr_push (ctx, initial); |
| dwarf_expr_eval (ctx, exp, len); |
| result = dwarf_expr_fetch (ctx, 0); |
| |
| if (ctx->in_reg) |
| result = read_reg (this_frame, result); |
| |
| free_dwarf_expr_context (ctx); |
| |
| return result; |
| } |
| |
| |
| static void |
| execute_cfa_program (struct dwarf2_fde *fde, gdb_byte *insn_ptr, |
| gdb_byte *insn_end, struct frame_info *this_frame, |
| struct dwarf2_frame_state *fs) |
| { |
| int eh_frame_p = fde->eh_frame_p; |
| CORE_ADDR pc = get_frame_pc (this_frame); |
| int bytes_read; |
| struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| |
| while (insn_ptr < insn_end && fs->pc <= pc) |
| { |
| gdb_byte insn = *insn_ptr++; |
| ULONGEST utmp, reg; |
| LONGEST offset; |
| |
| if ((insn & 0xc0) == DW_CFA_advance_loc) |
| fs->pc += (insn & 0x3f) * fs->code_align; |
| else if ((insn & 0xc0) == DW_CFA_offset) |
| { |
| reg = insn & 0x3f; |
| reg = dwarf2_frame_adjust_regnum (gdbarch, reg, eh_frame_p); |
| insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); |
| offset = utmp * 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; |
| } |
| else if ((insn & 0xc0) == DW_CFA_restore) |
| { |
| reg = insn & 0x3f; |
| dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p); |
| } |
| else |
| { |
| switch (insn) |
| { |
| case DW_CFA_set_loc: |
| fs->pc = read_encoded_value (fde->cie->unit, fde->cie->encoding, |
| fde->cie->addr_size, insn_ptr, |
| &bytes_read, fde->initial_location); |
| /* Apply the objfile offset for relocatable objects. */ |
| fs->pc += ANOFFSET (fde->cie->unit->objfile->section_offsets, |
| SECT_OFF_TEXT (fde->cie->unit->objfile)); |
| insn_ptr += bytes_read; |
| break; |
| |
| case DW_CFA_advance_loc1: |
| utmp = extract_unsigned_integer (insn_ptr, 1); |
| fs->pc += utmp * fs->code_align; |
| insn_ptr++; |
| break; |
| case DW_CFA_advance_loc2: |
| utmp = extract_unsigned_integer (insn_ptr, 2); |
| fs->pc += utmp * fs->code_align; |
| insn_ptr += 2; |
| break; |
| case DW_CFA_advance_loc4: |
| utmp = extract_unsigned_integer (insn_ptr, 4); |
| fs->pc += utmp * fs->code_align; |
| insn_ptr += 4; |
| break; |
| |
| case DW_CFA_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, &utmp); |
| offset = utmp * 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_restore_extended: |
| insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); |
| dwarf2_restore_rule (gdbarch, reg, fs, eh_frame_p); |
| break; |
| |
| case DW_CFA_undefined: |
| 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); |
| fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED; |
| break; |
| |
| case DW_CFA_same_value: |
| 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); |
| fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE; |
| break; |
| |
| case DW_CFA_register: |
| 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, &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. */ |
| { |
| 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 THIS_FRAME is 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 *this_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 *this_frame) |
| { |
| struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data); |
| |
| ops->init_reg (gdbarch, regnum, reg, this_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 |
| THIS_FRAME. */ |
| |
| static int |
| dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch, |
| struct frame_info *this_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, this_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 *this_frame, void **this_cache) |
| { |
| struct cleanup *old_chain; |
| struct gdbarch *gdbarch = get_frame_arch (this_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 the next frame is never supposed to return (i.e. a call |
| to abort), the compiler might optimize away the instruction at |
| its 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 = get_frame_address_in_block (this_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, this_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, this_frame, fs); |
| |
| /* Calculate the CFA. */ |
| switch (fs->cfa_how) |
| { |
| case CFA_REG_OFFSET: |
| cache->cfa = read_reg (this_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, this_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], this_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 *this_frame, void **this_cache, |
| struct frame_id *this_id) |
| { |
| struct dwarf2_frame_cache *cache = |
| dwarf2_frame_cache (this_frame, this_cache); |
| |
| if (cache->undefined_retaddr) |
| return; |
| |
| (*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame)); |
| } |
| |
| static struct value * |
| dwarf2_frame_prev_register (struct frame_info *this_frame, void **this_cache, |
| int regnum) |
| { |
| struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| struct dwarf2_frame_cache *cache = |
| dwarf2_frame_cache (this_frame, this_cache); |
| CORE_ADDR addr; |
| int realnum; |
| |
| 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. */ |
| return frame_unwind_got_optimized (this_frame, regnum); |
| |
| case DWARF2_FRAME_REG_SAVED_OFFSET: |
| addr = cache->cfa + cache->reg[regnum].loc.offset; |
| return frame_unwind_got_memory (this_frame, regnum, addr); |
| |
| case DWARF2_FRAME_REG_SAVED_REG: |
| realnum |
| = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg); |
| return frame_unwind_got_register (this_frame, regnum, realnum); |
| |
| case DWARF2_FRAME_REG_SAVED_EXP: |
| addr = execute_stack_op (cache->reg[regnum].loc.exp, |
| cache->reg[regnum].exp_len, |
| cache->addr_size, this_frame, cache->cfa); |
| return frame_unwind_got_memory (this_frame, regnum, addr); |
| |
| case DWARF2_FRAME_REG_SAVED_VAL_OFFSET: |
| addr = cache->cfa + cache->reg[regnum].loc.offset; |
| return frame_unwind_got_constant (this_frame, regnum, addr); |
| |
| case DWARF2_FRAME_REG_SAVED_VAL_EXP: |
| addr = execute_stack_op (cache->reg[regnum].loc.exp, |
| cache->reg[regnum].exp_len, |
| cache->addr_size, this_frame, cache->cfa); |
| return frame_unwind_got_constant (this_frame, regnum, addr); |
| |
| 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. */ |
| return frame_unwind_got_register (this_frame, regnum, regnum); |
| |
| case DWARF2_FRAME_REG_SAME_VALUE: |
| return frame_unwind_got_register (this_frame, regnum, regnum); |
| |
| case DWARF2_FRAME_REG_CFA: |
| return frame_unwind_got_address (this_frame, regnum, cache->cfa); |
| |
| case DWARF2_FRAME_REG_CFA_OFFSET: |
| addr = cache->cfa + cache->reg[regnum].loc.offset; |
| return frame_unwind_got_address (this_frame, regnum, addr); |
| |
| case DWARF2_FRAME_REG_RA_OFFSET: |
| addr = cache->reg[regnum].loc.offset; |
| regnum = gdbarch_dwarf2_reg_to_regnum |
| (gdbarch, cache->retaddr_reg.loc.reg); |
| addr += get_frame_register_unsigned (this_frame, regnum); |
| return frame_unwind_got_address (this_frame, regnum, addr); |
| |
| case DWARF2_FRAME_REG_FN: |
| return cache->reg[regnum].loc.fn (this_frame, this_cache, regnum); |
| |
| default: |
| internal_error (__FILE__, __LINE__, _("Unknown register rule.")); |
| } |
| } |
| |
| static int |
| dwarf2_frame_sniffer (const struct frame_unwind *self, |
| struct frame_info *this_frame, void **this_cache) |
| { |
| /* Grab an address that is guarenteed to reside somewhere within the |
| function. get_frame_pc(), with 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 could potentially |
| select the FDE of the previous function. */ |
| CORE_ADDR block_addr = get_frame_address_in_block (this_frame); |
| struct dwarf2_fde *fde = dwarf2_frame_find_fde (&block_addr); |
| if (!fde) |
| return 0; |
| |
| /* 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 (this_frame), |
| this_frame)) |
| return self->type == SIGTRAMP_FRAME; |
| |
| return self->type != SIGTRAMP_FRAME; |
| } |
| |
| static const struct frame_unwind dwarf2_frame_unwind = |
| { |
| NORMAL_FRAME, |
| dwarf2_frame_this_id, |
| dwarf2_frame_prev_register, |
| NULL, |
| dwarf2_frame_sniffer |
| }; |
| |
| static const struct frame_unwind dwarf2_signal_frame_unwind = |
| { |
| SIGTRAMP_FRAME, |
| dwarf2_frame_this_id, |
| dwarf2_frame_prev_register, |
| NULL, |
| dwarf2_frame_sniffer |
| }; |
| |
| /* Append the DWARF-2 frame unwinders to GDBARCH's list. */ |
| |
| void |
| dwarf2_append_unwinders (struct gdbarch *gdbarch) |
| { |
| frame_unwind_append_unwinder (gdbarch, &dwarf2_frame_unwind); |
| frame_unwind_append_unwinder (gdbarch, &dwarf2_signal_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 *this_frame, void **this_cache) |
| { |
| struct dwarf2_frame_cache *cache = |
| dwarf2_frame_cache (this_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 *this_frame) |
| { |
| CORE_ADDR block_addr = get_frame_address_in_block (this_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 (); |
| } |