diff options
Diffstat (limited to 'gdb/dwarf-frame.c')
| -rw-r--r-- | gdb/dwarf-frame.c | 967 |
1 files changed, 967 insertions, 0 deletions
diff --git a/gdb/dwarf-frame.c b/gdb/dwarf-frame.c new file mode 100644 index 00000000000..f584b799784 --- /dev/null +++ b/gdb/dwarf-frame.c @@ -0,0 +1,967 @@ +/* Frame unwinder for frames with DWARF Call Frame Information. + + Copyright 2003 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 2 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, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#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 "gdb_assert.h" +#include <stddef.h> +#include "gdb_string.h" + +#include "dwarf-frame.h" + +/* Call Frame Information (CFI). */ + +/* Common Information Entry (CIE). */ + +struct dwarf_cie +{ + /* 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. */ + unsigned char *initial_instructions; + unsigned char *end; + + struct dwarf_cie *next; +}; + +/* Frame Description Entry (FDE). */ + +struct dwarf_fde +{ + /* CIE for this FDE. */ + struct dwarf_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. */ + unsigned char *instructions; + unsigned char *end; + + struct dwarf_fde *next; +}; + +static struct dwarf_fde *dwarf_frame_find_fde (CORE_ADDR *pc); + + +/* Structure describing a frame state. */ + +struct dwarf_frame_state +{ + /* Each register save state can be described in terms of a CFA slot, + another register, or a location expression. */ + struct dwarf_frame_state_reg_info + { + struct dwarf_frame_state_reg + { + union { + LONGEST offset; + ULONGEST reg; + unsigned char *exp; + } loc; + enum { + REG_UNSAVED, + REG_SAVED_OFFSET, + REG_SAVED_REG, + REG_SAVED_EXP, + REG_UNMODIFIED + } how; + } *reg; + int num_regs; + + /* Used to implement DW_CFA_remember_state. */ + struct dwarf_frame_state_reg_info *prev; + } regs; + + LONGEST cfa_offset; + ULONGEST cfa_reg; + unsigned char *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 dwarf_frame_state_reg_info initial; + + /* The information we care about from the CIE. */ + LONGEST data_align; + ULONGEST code_align; + ULONGEST retaddr_column; +}; + +/* Store the length the expression for the CFA in the `cfa_reg' field, + which is unused in that case. */ +#define cfa_len cfa_reg + +/* Assert that the register set RS is large enough to store NUM_REGS + columns. If necessary, enlarge the register set. */ + +static void +dwarf_frame_state_alloc_regs (struct dwarf_frame_state_reg_info *rs, + int num_regs) +{ + size_t size = sizeof (struct dwarf_frame_state_reg); + + if (num_regs <= rs->num_regs) + return; + + rs->reg = (struct dwarf_frame_state_reg *) + xrealloc (rs->reg, num_regs * size); + + /* Initialize newly allocated registers. */ + memset (rs->reg + rs->num_regs * size, 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 dwarf_frame_state_reg * +dwarf_frame_state_copy_regs (struct dwarf_frame_state_reg_info *rs) +{ + size_t size = rs->num_regs * sizeof (struct dwarf_frame_state_reg_info); + struct dwarf_frame_state_reg *reg; + + reg = (struct dwarf_frame_state_reg *) xmalloc (size); + memcpy (reg, rs->reg, size); + + return reg; +} + +/* Release the memory allocated to register set RS. */ + +static void +dwarf_frame_state_free_regs (struct dwarf_frame_state_reg_info *rs) +{ + if (rs) + { + dwarf_frame_state_free_regs (rs->prev); + + xfree (rs->reg); + xfree (rs); + } +} + +/* Release the memory allocated to the frame state FS. */ + +static void +dwarf_frame_state_free (void *p) +{ + struct dwarf_frame_state *fs = p; + + dwarf_frame_state_free_regs (fs->initial.prev); + dwarf_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 *next_frame = (struct frame_info *) baton; + int regnum; + char *buf; + + regnum = DWARF2_REG_TO_REGNUM (reg); + + buf = (char *) alloca (register_size (current_gdbarch, regnum)); + frame_unwind_register (next_frame, regnum, buf); + return extract_typed_address (buf, builtin_type_void_data_ptr); +} + +static void +read_mem (void *baton, char *buf, CORE_ADDR addr, size_t len) +{ + read_memory (addr, buf, len); +} + +static CORE_ADDR +execute_stack_op (unsigned char *exp, ULONGEST len, + struct frame_info *next_frame, CORE_ADDR initial) +{ + struct dwarf_expr_context *ctx; + CORE_ADDR result; + + ctx = new_dwarf_expr_context (); + ctx->baton = next_frame; + ctx->read_reg = read_reg; + ctx->read_mem = read_mem; + + dwarf_expr_push (ctx, initial); + dwarf_expr_eval (ctx, exp, len); + result = dwarf_expr_fetch (ctx, 0); + + free_dwarf_expr_context (ctx); + + return result; +} + + +static void +execute_cfa_program (unsigned char *insn_ptr, unsigned char *insn_end, + struct frame_info *next_frame, + struct dwarf_frame_state *fs) +{ + CORE_ADDR pc = frame_pc_unwind (next_frame); + int bytes_read; + + while (insn_ptr < insn_end && fs->pc <= pc) + { + unsigned char 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; + insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); + offset = utmp * fs->data_align; + dwarf_frame_state_alloc_regs (&fs->regs, reg + 1); + fs->regs.reg[reg].how = REG_SAVED_OFFSET; + fs->regs.reg[reg].loc.offset = offset; + } + else if ((insn & 0xc0) == DW_CFA_restore) + { + gdb_assert (fs->initial.reg); + reg = insn & 0x3f; + dwarf_frame_state_alloc_regs (&fs->regs, reg + 1); + fs->regs.reg[reg] = fs->initial.reg[reg]; + } + else + { + switch (insn) + { + case DW_CFA_set_loc: + fs->pc = dwarf2_read_address (insn_ptr, insn_end, &bytes_read); + 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, ®); + insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); + offset = utmp * fs->data_align; + dwarf_frame_state_alloc_regs (&fs->regs, reg + 1); + fs->regs.reg[reg].how = REG_SAVED_OFFSET; + fs->regs.reg[reg].loc.offset = offset; + break; + + case DW_CFA_restore_extended: + gdb_assert (fs->initial.reg); + insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); + dwarf_frame_state_alloc_regs (&fs->regs, reg + 1); + fs->regs.reg[reg] = fs->initial.reg[reg]; + break; + + case DW_CFA_undefined: + insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); + dwarf_frame_state_alloc_regs (&fs->regs, reg + 1); + fs->regs.reg[reg].how = REG_UNSAVED; + break; + + case DW_CFA_same_value: + insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); + dwarf_frame_state_alloc_regs (&fs->regs, reg + 1); + fs->regs.reg[reg].how = REG_UNMODIFIED; + break; + + case DW_CFA_register: + insn_ptr = read_uleb128 (insn_ptr, insn_end, ®); + insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); + dwarf_frame_state_alloc_regs (&fs->regs, reg + 1); + fs->regs.reg[reg].loc.reg = utmp; + break; + + case DW_CFA_remember_state: + { + struct dwarf_frame_state_reg_info *new_rs; + + new_rs = XMALLOC (struct dwarf_frame_state_reg_info); + *new_rs = fs->regs; + fs->regs.reg = dwarf_frame_state_copy_regs (&fs->regs); + fs->regs.prev = new_rs; + } + break; + + case DW_CFA_restore_state: + { + struct dwarf_frame_state_reg_info *old_rs = fs->regs.prev; + + gdb_assert (old_rs); + + 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); + 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_how = CFA_REG_OFFSET; + break; + + case DW_CFA_def_cfa_offset: + insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_offset); + /* cfa_how deliberately not set. */ + break; + + case DW_CFA_def_cfa_expression: + insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_len); + fs->cfa_exp = insn_ptr; + fs->cfa_how = CFA_EXP; + insn_ptr += fs->cfa_len; + break; + + case DW_CFA_nop: + break; + + case DW_CFA_GNU_args_size: + /* Ignored. */ + insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp); + break; + + default: + internal_error (__FILE__, __LINE__, "Unknown CFI encountered."); + } + } + } + + /* Don't allow remember/restore between CIE and FDE programs. */ + dwarf_frame_state_free_regs (fs->regs.prev); + fs->regs.prev = NULL; +} + +struct dwarf_frame_cache +{ + /* DWARF Call Frame Address. */ + CORE_ADDR cfa; + + /* Saved registers, indexed by GDB register number, not by DWARF + register number. */ + struct dwarf_frame_state_reg *reg; +}; + +struct dwarf_frame_cache * +dwarf_frame_cache (struct frame_info *next_frame, void **this_cache) +{ + struct cleanup *old_chain; + int num_regs = NUM_REGS + NUM_PSEUDO_REGS; + struct dwarf_frame_cache *cache; + struct dwarf_frame_state *fs; + struct dwarf_fde *fde; + int reg; + + if (*this_cache) + return *this_cache; + + /* Allocate a new cache. */ + cache = FRAME_OBSTACK_ZALLOC (struct dwarf_frame_cache); + cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf_frame_state_reg); + + /* Allocate and initialize the frame state. */ + fs = XMALLOC (struct dwarf_frame_state); + memset (fs, 0, sizeof (struct dwarf_frame_state)); + old_chain = make_cleanup (dwarf_frame_state_free, fs); + + /* Unwind the PC and find the correct FDE. */ + fs->pc = frame_pc_unwind (next_frame); + fde = dwarf_frame_find_fde (&fs->pc); + + /* 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; + + /* First decode all the insns in the CIE. */ + execute_cfa_program (fde->cie->initial_instructions, + fde->cie->end, next_frame, fs); + + /* Save the initialized register set. */ + fs->initial = fs->regs; + fs->initial.reg = dwarf_frame_state_copy_regs (&fs->regs); + + /* Then decode the insns in the FDE up to our target PC. */ + execute_cfa_program (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); + cache->cfa += fs->cfa_offset; + break; + + case CFA_EXP: + cache->cfa = execute_stack_op (fs->cfa_exp, fs->cfa_len, next_frame, 0); + break; + + default: + internal_error (__FILE__, __LINE__, "Unknown CFA rule."); + } + + /* Save the register info in the cache. */ + for (reg = 0; reg < fs->regs.num_regs; reg++) + { + /* Use the GDB register number as index. */ + int regnum = DWARF2_REG_TO_REGNUM (reg); + + if (regnum >= 0 && regnum < num_regs) + cache->reg[regnum] = fs->regs.reg[reg]; + } + + /* Make sure we have stored the return addess value. */ + if (cache->reg[PC_REGNUM].how == REG_UNSAVED) + cache->reg[PC_REGNUM] = fs->regs.reg[fs->retaddr_column]; + + do_cleanups (old_chain); + + *this_cache = cache; + return cache; +} + +static void +dwarf_frame_this_id (struct frame_info *next_frame, void **this_cache, + struct frame_id *this_id) +{ + struct dwarf_frame_cache *cache = dwarf_frame_cache (next_frame, this_cache); + + (*this_id) = frame_id_build (cache->cfa, frame_func_unwind (next_frame)); +} + +static void +dwarf_frame_prev_register (struct frame_info *next_frame, void **this_cache, + int regnum, int *optimizedp, + enum lval_type *lvalp, CORE_ADDR *addrp, + int *realnump, void *valuep) +{ + struct dwarf_frame_cache *cache = dwarf_frame_cache (next_frame, this_cache); + + switch (cache->reg[regnum].how) + { + case REG_UNSAVED: + *optimizedp = 1; + *lvalp = not_lval; + *addrp = 0; + *realnump = -1; + if (regnum == SP_REGNUM) + { + /* GCC defines the CFA as the value of the stack pointer + just before the call instruction is executed. Do other + compilers use the same definition? */ + *optimizedp = 0; + if (valuep) + { + /* Store the value. */ + store_typed_address (valuep, builtin_type_void_data_ptr, + cache->cfa); + } + } + else 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 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 (current_gdbarch, regnum)); + } + break; + + case REG_SAVED_REG: + *optimizedp = 0; + *lvalp = lval_register; + *addrp = 0; + *realnump = DWARF2_REG_TO_REGNUM (cache->reg[regnum].loc.reg); + if (valuep) + { + /* Read the value from the register. */ + frame_unwind_register (next_frame, *realnump, valuep); + } + break; + + case REG_UNMODIFIED: + frame_register_unwind (next_frame, regnum, + optimizedp, lvalp, addrp, realnump, valuep); + break; + + default: + internal_error (__FILE__, __LINE__, "Unknown register rule."); + } +} + +static const struct frame_unwind dwarf_frame_unwind = +{ + NORMAL_FRAME, + dwarf_frame_this_id, + dwarf_frame_prev_register +}; + +const struct frame_unwind * +dwarf_frame_p (CORE_ADDR pc) +{ + if (dwarf_frame_find_fde (&pc)) + return &dwarf_frame_unwind; + + return NULL; +} + +static CORE_ADDR +dwarf_frame_base_address (struct frame_info *next_frame, void **this_cache) +{ + struct dwarf_frame_cache *cache = dwarf_frame_cache (next_frame, this_cache); + + return cache->cfa; +} + +static const struct frame_base dwarf_frame_base = +{ + &dwarf_frame_unwind, + dwarf_frame_base_address, + dwarf_frame_base_address, + dwarf_frame_base_address +}; + +const struct frame_base * +dwarf_frame_base_p (CORE_ADDR pc) +{ + if (dwarf_frame_find_fde (&pc)) + return &dwarf_frame_base; + + return NULL; +} + +/* 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 dwarf_cie *cie; + + /* Address size for this unit - from unit header. */ + unsigned char addr_size; + + /* Pointer to the .debug_frame section loaded into memory. */ + char *dwarf_frame_buffer; + + /* Length of the loaded .debug_frame section. */ + unsigned long dwarf_frame_size; +}; + +static unsigned int +read_1_byte (bfd *bfd, char *buf) +{ + return bfd_get_8 (abfd, (bfd_byte *) buf); +} + +static unsigned int +read_4_bytes (bfd *abfd, char *buf) +{ + return bfd_get_32 (abfd, (bfd_byte *) buf); +} + +static ULONGEST +read_8_bytes (bfd *abfd, char *buf) +{ + return bfd_get_64 (abfd, (bfd_byte *) buf); +} + +static ULONGEST +read_unsigned_leb128 (bfd *abfd, char *buf, unsigned int *bytes_read_ptr) +{ + ULONGEST result; + unsigned int num_read; + int shift; + unsigned char 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, char *buf, unsigned int *bytes_read_ptr) +{ + LONGEST result; + int shift; + unsigned int num_read; + unsigned char 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 < 32) && (byte & 0x40)) + result |= -(1 << shift); + + *bytes_read_ptr = num_read; + + return result; +} + +static ULONGEST +read_initial_length (bfd *abfd, char *buf, unsigned int *bytes_read_ptr) +{ + LONGEST result; + + result = bfd_get_32 (abfd, (bfd_byte *) buf); + if (result == 0xffffffff) + { + result = bfd_get_64 (abfd, (bfd_byte *) buf + 4); + *bytes_read_ptr = 12; + } + else + *bytes_read_ptr = 4; + + return result; +} + +CORE_ADDR +read_address (struct comp_unit *unit, char *buf) +{ + switch (unit->addr_size) + { + case 8: + return bfd_get_64 (unit->abfd, (bfd_byte *) buf); + case 4: + return bfd_get_32 (unit->abfd, (bfd_byte *) buf); + case 2: + return bfd_get_16 (unit->abfd, (bfd_byte *) buf); + default: + internal_error (__FILE__, __LINE__, "Invalid address"); + } +} + + +/* 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 dwarf_cie * +find_cie (struct comp_unit *unit, ULONGEST cie_pointer) +{ + struct dwarf_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 dwarf_cie *cie) +{ + cie->next = unit->cie; + unit->cie = cie; +} + +/* Find the FDE for *PC. Return a pointer to the FDE, and store the + inital location associated with it into *PC. */ + +static struct dwarf_fde * +dwarf_frame_find_fde (CORE_ADDR *pc) +{ + struct objfile *objfile; + + ALL_OBJFILES (objfile) + { + struct dwarf_fde *fde = objfile->sym_private; + CORE_ADDR baseaddr; + + baseaddr = ANOFFSET (objfile->section_offsets, SECT_OFF_TEXT (objfile)); + + while (fde) + { + if (*pc >= fde->initial_location + baseaddr + && *pc < fde->initial_location + baseaddr + fde->address_range) + { + *pc = fde->initial_location + baseaddr; + return fde; + } + + fde = fde->next; + } + } + + return NULL; +} + +static void +add_fde (struct comp_unit *unit, struct dwarf_fde *fde) +{ + fde->next = unit->objfile->sym_private; + unit->objfile->sym_private = fde; +} + +/* Read and the CIE or FDE in BUF and decode it. */ + +static char * +decode_frame_entry (struct comp_unit *unit, char *buf) +{ + LONGEST length; + unsigned int bytes_read; + int dwarf64_p = 0; + int cie_p = 0; + ULONGEST cie_pointer; + char *start = buf; + char *end; + + length = read_initial_length (unit->abfd, buf, &bytes_read); + buf += bytes_read; + end = buf + length; + + if (bytes_read == 12) + dwarf64_p = 1; + + if (dwarf64_p) + { + cie_pointer = read_8_bytes (unit->abfd, buf); + buf += 8; +#ifdef CC_HAS_LONG_LONG + if (cie_pointer == 0xffffffffffffffffULL) + cie_p = 1; +#endif + } + else + { + cie_pointer = read_4_bytes (unit->abfd, buf); + buf += 4; + if (cie_pointer == DW_CIE_ID) + cie_p = 1; + } + + if (cie_p) + { + /* This is a CIE. */ + struct dwarf_cie *cie; + + /* 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 dwarf_cie *) + obstack_alloc (&unit->objfile->psymbol_obstack, + sizeof (struct dwarf_cie)); + cie->cie_pointer = cie_pointer; + + /* Check version number. */ + gdb_assert (read_1_byte (unit->abfd, buf) == DW_CIE_VERSION); + buf += 1; + + /* Skip augmentation. */ + gdb_assert (read_1_byte (unit->abfd, buf) == 0); + buf += 1; + + 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; + + cie->return_address_register = read_1_byte (unit->abfd, buf); + buf += 1; + + cie->initial_instructions = buf; + cie->end = end; + + add_cie (unit, cie); + } + else + { + /* This is a FDE. */ + struct dwarf_fde *fde; + + fde = (struct dwarf_fde *) + obstack_alloc (&unit->objfile->psymbol_obstack, + sizeof (struct dwarf_fde)); + fde->cie = find_cie (unit, cie_pointer); + if (fde->cie == NULL) + { + decode_frame_entry (unit, unit->dwarf_frame_buffer + cie_pointer); + fde->cie = find_cie (unit, cie_pointer); + } + + gdb_assert (fde->cie != NULL); + + fde->initial_location = read_address (unit, buf); + buf += unit->addr_size; + + fde->address_range = read_address (unit, buf); + buf += unit->addr_size; + + fde->instructions = buf; + fde->end = end; + + add_fde (unit, fde); + } + + return end; +} + + +/* FIXME: kettenis/20030504: This still needs to be integrated with + dwarf2read.c in a better way. */ + +/* Imported from dwarf2read.c. */ +extern file_ptr dwarf_frame_offset; +extern unsigned int dwarf_frame_size; +extern asection *dwarf_frame_section; + +/* Imported from dwarf2read.c. */ +extern char *dwarf2_read_section (struct objfile *objfile, file_ptr offset, + unsigned int size, asection *sectp); + +void +dwarf2_build_frame_info (struct objfile *objfile) +{ + struct comp_unit unit; + char *frame_ptr; + + if (!dwarf_frame_offset) + return; + + /* Build a minimal decoding of the DWARF2 compilation unit. */ + + unit.abfd = objfile->obfd; + unit.objfile = objfile; + unit.cie = NULL; + unit.addr_size = objfile->obfd->arch_info->bits_per_address / 8; + unit.dwarf_frame_buffer = dwarf2_read_section (objfile, + dwarf_frame_offset, + dwarf_frame_size, + dwarf_frame_section); + unit.dwarf_frame_size = dwarf_frame_size; + + 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); +} |