diff options
| -rw-r--r-- | gdb/ChangeLog | 10 | ||||
| -rw-r--r-- | gdb/i386-tdep.c | 94 |
2 files changed, 103 insertions, 1 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 30896bf..a6c8169 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,13 @@ +2009-07-12 Michael Snyder <msnyder@vmware.com> + + * i386-tdep.c: Add a frame unwinder for function epilogues. + (i386_in_function_epilogue_p): New function. + (i386_epilogue_frame_sniffer): New function. + (i386_epilogue_frame_cache): New function. + (i386_epilogue_frame_this_id): New function. + (i386_epilogue_frame_unwind): New struct frame_unwind. + (i386_gdbarch_init): Hook the new unwinder. + 2009-07-11 Hui Zhu <teawater@gmail.com> * cli/cli-cmds.c (disassemble_command): Add a new modifier /r diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c index bf3a844..2d73785 100644 --- a/gdb/i386-tdep.c +++ b/gdb/i386-tdep.c @@ -1487,6 +1487,89 @@ static const struct frame_unwind i386_frame_unwind = NULL, default_frame_sniffer }; + +/* Normal frames, but in a function epilogue. */ + +/* The epilogue is defined here as the 'ret' instruction, which will + follow any instruction such as 'leave' or 'pop %ebp' that destroys + the function's stack frame. */ + +static int +i386_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc) +{ + gdb_byte insn; + + if (target_read_memory (pc, &insn, 1)) + return 0; /* Can't read memory at pc. */ + + if (insn != 0xc3) /* 'ret' instruction. */ + return 0; + + return 1; +} + +static int +i386_epilogue_frame_sniffer (const struct frame_unwind *self, + struct frame_info *this_frame, + void **this_prologue_cache) +{ + if (frame_relative_level (this_frame) == 0) + return i386_in_function_epilogue_p (get_frame_arch (this_frame), + get_frame_pc (this_frame)); + else + return 0; +} + +static struct i386_frame_cache * +i386_epilogue_frame_cache (struct frame_info *this_frame, void **this_cache) +{ + struct gdbarch *gdbarch = get_frame_arch (this_frame); + enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); + struct i386_frame_cache *cache; + gdb_byte buf[4]; + + if (*this_cache) + return *this_cache; + + cache = i386_alloc_frame_cache (); + *this_cache = cache; + + /* Cache base will be %esp plus cache->sp_offset (-4). */ + get_frame_register (this_frame, I386_ESP_REGNUM, buf); + cache->base = extract_unsigned_integer (buf, 4, + byte_order) + cache->sp_offset; + + /* Cache pc will be the frame func. */ + cache->pc = get_frame_pc (this_frame); + + /* The saved %esp will be at cache->base plus 8. */ + cache->saved_sp = cache->base + 8; + + /* The saved %eip will be at cache->base plus 4. */ + cache->saved_regs[I386_EIP_REGNUM] = cache->base + 4; + + return cache; +} + +static void +i386_epilogue_frame_this_id (struct frame_info *this_frame, + void **this_cache, + struct frame_id *this_id) +{ + struct i386_frame_cache *cache = i386_epilogue_frame_cache (this_frame, + this_cache); + + (*this_id) = frame_id_build (cache->base + 8, cache->pc); +} + +static const struct frame_unwind i386_epilogue_frame_unwind = +{ + NORMAL_FRAME, + i386_epilogue_frame_this_id, + i386_frame_prev_register, + NULL, + i386_epilogue_frame_sniffer +}; /* Signal trampolines. */ @@ -5329,7 +5412,15 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) /* Helper for function argument information. */ set_gdbarch_fetch_pointer_argument (gdbarch, i386_fetch_pointer_argument); - /* Hook in the DWARF CFI frame unwinder. */ + /* Hook the function epilogue frame unwinder. This unwinder is + appended to the list first, so that it supercedes the Dwarf + unwinder in function epilogues (where the Dwarf unwinder + currently fails). */ + frame_unwind_append_unwinder (gdbarch, &i386_epilogue_frame_unwind); + + /* Hook in the DWARF CFI frame unwinder. This unwinder is appended + to the list before the prologue-based unwinders, so that Dwarf + CFI info will be used if it is available. */ dwarf2_append_unwinders (gdbarch); frame_base_set_default (gdbarch, &i386_frame_base); @@ -5337,6 +5428,7 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) /* Hook in ABI-specific overrides, if they have been registered. */ gdbarch_init_osabi (info, gdbarch); + /* Hook in the legacy prologue-based unwinders last (fallback). */ frame_unwind_append_unwinder (gdbarch, &i386_sigtramp_frame_unwind); frame_unwind_append_unwinder (gdbarch, &i386_frame_unwind); |