/* Definitions for frame unwinder, for GDB, the GNU debugger. Copyright (C) 2003-2004, 2007-2012 Free Software Foundation, Inc. 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 "frame.h" #include "frame-unwind.h" #include "dummy-frame.h" #include "inline-frame.h" #include "value.h" #include "regcache.h" #include "exceptions.h" #include "gdb_assert.h" #include "gdb_obstack.h" static struct gdbarch_data *frame_unwind_data; struct frame_unwind_table_entry { const struct frame_unwind *unwinder; struct frame_unwind_table_entry *next; }; struct frame_unwind_table { struct frame_unwind_table_entry *list; /* The head of the OSABI part of the search list. */ struct frame_unwind_table_entry **osabi_head; }; static void * frame_unwind_init (struct obstack *obstack) { struct frame_unwind_table *table = OBSTACK_ZALLOC (obstack, struct frame_unwind_table); /* Start the table out with a few default sniffers. OSABI code can't override this. */ table->list = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry); table->list->unwinder = &dummy_frame_unwind; table->list->next = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry); table->list->next->unwinder = &inline_frame_unwind; /* The insertion point for OSABI sniffers. */ table->osabi_head = &table->list->next->next; return table; } void frame_unwind_prepend_unwinder (struct gdbarch *gdbarch, const struct frame_unwind *unwinder) { struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data); struct frame_unwind_table_entry *entry; /* Insert the new entry at the start of the list. */ entry = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry); entry->unwinder = unwinder; entry->next = (*table->osabi_head); (*table->osabi_head) = entry; } void frame_unwind_append_unwinder (struct gdbarch *gdbarch, const struct frame_unwind *unwinder) { struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data); struct frame_unwind_table_entry **ip; /* Find the end of the list and insert the new entry there. */ for (ip = table->osabi_head; (*ip) != NULL; ip = &(*ip)->next); (*ip) = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry); (*ip)->unwinder = unwinder; } /* Iterate through sniffers for THIS_FRAME frame until one returns with an unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set by this function. Possibly initialize THIS_CACHE. */ void frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache) { struct gdbarch *gdbarch = get_frame_arch (this_frame); struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data); struct frame_unwind_table_entry *entry; for (entry = table->list; entry != NULL; entry = entry->next) { struct cleanup *old_cleanup; volatile struct gdb_exception ex; int res = 0; old_cleanup = frame_prepare_for_sniffer (this_frame, entry->unwinder); TRY_CATCH (ex, RETURN_MASK_ERROR) { res = entry->unwinder->sniffer (entry->unwinder, this_frame, this_cache); } if (ex.reason < 0 && ex.error == NOT_AVAILABLE_ERROR) { /* This usually means that not even the PC is available, thus most unwinders aren't able to determine if they're the best fit. Keep trying. Fallback prologue unwinders should always accept the frame. */ } else if (ex.reason < 0) throw_exception (ex); else if (res) { discard_cleanups (old_cleanup); return; } do_cleanups (old_cleanup); } internal_error (__FILE__, __LINE__, _("frame_unwind_find_by_frame failed")); } /* A default frame sniffer which always accepts the frame. Used by fallback prologue unwinders. */ int default_frame_sniffer (const struct frame_unwind *self, struct frame_info *this_frame, void **this_prologue_cache) { return 1; } /* A default frame unwinder stop_reason callback that always claims the frame is unwindable. */ enum unwind_stop_reason default_frame_unwind_stop_reason (struct frame_info *this_frame, void **this_cache) { return UNWIND_NO_REASON; } /* Helper functions for value-based register unwinding. These return a (possibly lazy) value of the appropriate type. */ /* Return a value which indicates that FRAME did not save REGNUM. */ struct value * frame_unwind_got_optimized (struct frame_info *frame, int regnum) { struct gdbarch *gdbarch = frame_unwind_arch (frame); struct value *reg_val; reg_val = value_zero (register_type (gdbarch, regnum), not_lval); set_value_optimized_out (reg_val, 1); return reg_val; } /* Return a value which indicates that FRAME copied REGNUM into register NEW_REGNUM. */ struct value * frame_unwind_got_register (struct frame_info *frame, int regnum, int new_regnum) { return value_of_register_lazy (frame, new_regnum); } /* Return a value which indicates that FRAME saved REGNUM in memory at ADDR. */ struct value * frame_unwind_got_memory (struct frame_info *frame, int regnum, CORE_ADDR addr) { struct gdbarch *gdbarch = frame_unwind_arch (frame); struct value *v = value_at_lazy (register_type (gdbarch, regnum), addr); set_value_stack (v, 1); return v; } /* Return a value which indicates that FRAME's saved version of REGNUM has a known constant (computed) value of VAL. */ struct value * frame_unwind_got_constant (struct frame_info *frame, int regnum, ULONGEST val) { struct gdbarch *gdbarch = frame_unwind_arch (frame); enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); struct value *reg_val; reg_val = value_zero (register_type (gdbarch, regnum), not_lval); store_unsigned_integer (value_contents_writeable (reg_val), register_size (gdbarch, regnum), byte_order, val); return reg_val; } struct value * frame_unwind_got_bytes (struct frame_info *frame, int regnum, gdb_byte *buf) { struct gdbarch *gdbarch = frame_unwind_arch (frame); struct value *reg_val; reg_val = value_zero (register_type (gdbarch, regnum), not_lval); memcpy (value_contents_raw (reg_val), buf, register_size (gdbarch, regnum)); return reg_val; } /* Return a value which indicates that FRAME's saved version of REGNUM has a known constant (computed) value of ADDR. Convert the CORE_ADDR to a target address if necessary. */ struct value * frame_unwind_got_address (struct frame_info *frame, int regnum, CORE_ADDR addr) { struct gdbarch *gdbarch = frame_unwind_arch (frame); struct value *reg_val; reg_val = value_zero (register_type (gdbarch, regnum), not_lval); pack_long (value_contents_writeable (reg_val), register_type (gdbarch, regnum), addr); return reg_val; } /* -Wmissing-prototypes */ extern initialize_file_ftype _initialize_frame_unwind; void _initialize_frame_unwind (void) { frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init); }