| /* Code dealing with dummy stack frames, for GDB, the GNU debugger. |
| |
| Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, |
| 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007, 2008 |
| 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 "dummy-frame.h" |
| #include "regcache.h" |
| #include "frame.h" |
| #include "inferior.h" |
| #include "gdb_assert.h" |
| #include "frame-unwind.h" |
| #include "command.h" |
| #include "gdbcmd.h" |
| #include "gdb_string.h" |
| |
| /* Dummy frame. This saves the processor state just prior to setting |
| up the inferior function call. Older targets save the registers |
| on the target stack (but that really slows down function calls). */ |
| |
| struct dummy_frame |
| { |
| struct dummy_frame *next; |
| /* This frame's ID. Must match the value returned by |
| gdbarch_dummy_id. */ |
| struct frame_id id; |
| /* The caller's regcache. */ |
| struct regcache *regcache; |
| }; |
| |
| static struct dummy_frame *dummy_frame_stack = NULL; |
| |
| /* Function: deprecated_pc_in_call_dummy (pc) |
| |
| Return non-zero if the PC falls in a dummy frame created by gdb for |
| an inferior call. The code below which allows gdbarch_decr_pc_after_break |
| is for infrun.c, which may give the function a PC without that |
| subtracted out. |
| |
| FIXME: cagney/2002-11-23: This is silly. Surely "infrun.c" can |
| figure out what the real PC (as in the resume address) is BEFORE |
| calling this function. |
| |
| NOTE: cagney/2004-08-02: I'm pretty sure that, with the introduction of |
| infrun.c:adjust_pc_after_break (thanks), this function is now |
| always called with a correctly adjusted PC! |
| |
| NOTE: cagney/2004-08-02: Code should not need to call this. */ |
| |
| int |
| deprecated_pc_in_call_dummy (CORE_ADDR pc) |
| { |
| struct dummy_frame *dummyframe; |
| for (dummyframe = dummy_frame_stack; |
| dummyframe != NULL; |
| dummyframe = dummyframe->next) |
| { |
| if ((pc >= dummyframe->id.code_addr) |
| && (pc <= dummyframe->id.code_addr |
| + gdbarch_decr_pc_after_break (current_gdbarch))) |
| return 1; |
| } |
| return 0; |
| } |
| |
| /* Push the caller's state, along with the dummy frame info, onto a |
| dummy-frame stack. */ |
| |
| void |
| dummy_frame_push (struct regcache *caller_regcache, |
| const struct frame_id *dummy_id) |
| { |
| struct gdbarch *gdbarch = get_regcache_arch (caller_regcache); |
| struct dummy_frame *dummy_frame; |
| |
| /* Check to see if there are stale dummy frames, perhaps left over |
| from when a longjump took us out of a function that was called by |
| the debugger. */ |
| dummy_frame = dummy_frame_stack; |
| while (dummy_frame) |
| /* FIXME: cagney/2004-08-02: Should just test IDs. */ |
| if (frame_id_inner (gdbarch, dummy_frame->id, (*dummy_id))) |
| /* Stale -- destroy! */ |
| { |
| dummy_frame_stack = dummy_frame->next; |
| regcache_xfree (dummy_frame->regcache); |
| xfree (dummy_frame); |
| dummy_frame = dummy_frame_stack; |
| } |
| else |
| dummy_frame = dummy_frame->next; |
| |
| dummy_frame = XZALLOC (struct dummy_frame); |
| dummy_frame->regcache = caller_regcache; |
| dummy_frame->id = (*dummy_id); |
| dummy_frame->next = dummy_frame_stack; |
| dummy_frame_stack = dummy_frame; |
| } |
| |
| /* Return the dummy frame cache, it contains both the ID, and a |
| pointer to the regcache. */ |
| struct dummy_frame_cache |
| { |
| struct frame_id this_id; |
| struct regcache *prev_regcache; |
| }; |
| |
| int |
| dummy_frame_sniffer (const struct frame_unwind *self, |
| struct frame_info *this_frame, |
| void **this_prologue_cache) |
| { |
| struct dummy_frame *dummyframe; |
| struct frame_id this_id; |
| |
| /* When unwinding a normal frame, the stack structure is determined |
| by analyzing the frame's function's code (be it using brute force |
| prologue analysis, or the dwarf2 CFI). In the case of a dummy |
| frame, that simply isn't possible. The PC is either the program |
| entry point, or some random address on the stack. Trying to use |
| that PC to apply standard frame ID unwind techniques is just |
| asking for trouble. */ |
| |
| /* Don't bother unles there is at least one dummy frame. */ |
| if (dummy_frame_stack != NULL) |
| { |
| /* Use an architecture specific method to extract this frame's |
| dummy ID, assuming it is a dummy frame. */ |
| this_id = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame); |
| |
| /* Use that ID to find the corresponding cache entry. */ |
| for (dummyframe = dummy_frame_stack; |
| dummyframe != NULL; |
| dummyframe = dummyframe->next) |
| { |
| if (frame_id_eq (dummyframe->id, this_id)) |
| { |
| struct dummy_frame_cache *cache; |
| cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache); |
| cache->prev_regcache = dummyframe->regcache; |
| cache->this_id = this_id; |
| (*this_prologue_cache) = cache; |
| return 1; |
| } |
| } |
| } |
| return 0; |
| } |
| |
| /* Given a call-dummy dummy-frame, return the registers. Here the |
| register value is taken from the local copy of the register buffer. */ |
| |
| static struct value * |
| dummy_frame_prev_register (struct frame_info *this_frame, |
| void **this_prologue_cache, |
| int regnum) |
| { |
| struct dummy_frame_cache *cache = (*this_prologue_cache); |
| struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| struct value *reg_val; |
| |
| /* The dummy-frame sniffer always fills in the cache. */ |
| gdb_assert (cache != NULL); |
| |
| /* Describe the register's location. Generic dummy frames always |
| have the register value in an ``expression''. */ |
| reg_val = value_zero (register_type (gdbarch, regnum), not_lval); |
| |
| /* Use the regcache_cooked_read() method so that it, on the fly, |
| constructs either a raw or pseudo register from the raw |
| register cache. */ |
| regcache_cooked_read (cache->prev_regcache, regnum, |
| value_contents_writeable (reg_val)); |
| return reg_val; |
| } |
| |
| /* Assuming that THIS frame is a dummy, return the ID of THIS frame. That ID is |
| determined by examining the NEXT frame's unwound registers using |
| the method dummy_id(). As a side effect, THIS dummy frame's |
| dummy cache is located and and saved in THIS_PROLOGUE_CACHE. */ |
| |
| static void |
| dummy_frame_this_id (struct frame_info *this_frame, |
| void **this_prologue_cache, |
| struct frame_id *this_id) |
| { |
| /* The dummy-frame sniffer always fills in the cache. */ |
| struct dummy_frame_cache *cache = (*this_prologue_cache); |
| gdb_assert (cache != NULL); |
| (*this_id) = cache->this_id; |
| } |
| |
| static const struct frame_unwind dummy_frame_unwinder = |
| { |
| DUMMY_FRAME, |
| dummy_frame_this_id, |
| dummy_frame_prev_register, |
| NULL, |
| dummy_frame_sniffer, |
| }; |
| |
| const struct frame_unwind *const dummy_frame_unwind = { |
| &dummy_frame_unwinder |
| }; |
| |
| static void |
| fprint_dummy_frames (struct ui_file *file) |
| { |
| struct dummy_frame *s; |
| for (s = dummy_frame_stack; s != NULL; s = s->next) |
| { |
| gdb_print_host_address (s, file); |
| fprintf_unfiltered (file, ":"); |
| fprintf_unfiltered (file, " id="); |
| fprint_frame_id (file, s->id); |
| fprintf_unfiltered (file, "\n"); |
| } |
| } |
| |
| static void |
| maintenance_print_dummy_frames (char *args, int from_tty) |
| { |
| if (args == NULL) |
| fprint_dummy_frames (gdb_stdout); |
| else |
| { |
| struct ui_file *file = gdb_fopen (args, "w"); |
| if (file == NULL) |
| perror_with_name (_("maintenance print dummy-frames")); |
| fprint_dummy_frames (file); |
| ui_file_delete (file); |
| } |
| } |
| |
| extern void _initialize_dummy_frame (void); |
| |
| void |
| _initialize_dummy_frame (void) |
| { |
| add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames, |
| _("Print the contents of the internal dummy-frame stack."), |
| &maintenanceprintlist); |
| |
| } |