1 /* Code dealing with dummy stack frames, for GDB, the GNU debugger. 2 3 Copyright 2002 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 59 Temple Place - Suite 330, 20 Boston, MA 02111-1307, USA. */ 21 22 #if !defined (DUMMY_FRAME_H) 23 #define DUMMY_FRAME_H 1 24 25 struct frame_info; 26 struct regcache; 27 struct frame_unwind; 28 struct frame_id; 29 30 /* GENERIC DUMMY FRAMES 31 32 The following code serves to maintain the dummy stack frames for 33 inferior function calls (ie. when gdb calls into the inferior via 34 call_function_by_hand). This code saves the machine state before 35 the call in host memory, so we must maintain an independent stack 36 and keep it consistant etc. I am attempting to make this code 37 generic enough to be used by many targets. 38 39 The cheapest and most generic way to do CALL_DUMMY on a new target 40 is probably to define CALL_DUMMY to be empty, 41 DEPRECATED_CALL_DUMMY_LENGTH to zero, and CALL_DUMMY_LOCATION to 42 AT_ENTRY. Then you must remember to define PUSH_RETURN_ADDRESS, 43 because no call instruction will be being executed by the target. 44 Also DEPRECATED_FRAME_CHAIN_VALID as 45 generic_{file,func}_frame_chain_valid and do not set 46 DEPRECATED_FIX_CALL_DUMMY. */ 47 48 /* If the PC falls in a dummy frame, return a dummy frame 49 unwinder. */ 50 51 extern const struct frame_unwind *dummy_frame_sniffer (struct frame_info *next_frame); 52 53 /* Does the PC fall in a dummy frame? 54 55 This function is used by "frame.c" when creating a new `struct 56 frame_info'. 57 58 Note that there is also very similar code in breakpoint.c (where 59 the bpstat stop reason is computed). It is looking for a PC 60 falling on a dummy_frame breakpoint. Perhaphs this, and that code 61 should be combined? 62 63 Architecture dependant code, that has access to a frame, should not 64 use this function. Instead (get_frame_type() == DUMMY_FRAME) 65 should be used. 66 67 Hmm, but what about threads? When the dummy-frame code tries to 68 relocate a dummy frame's saved registers it definitly needs to 69 differentiate between threads (otherwize it will do things like 70 clean-up the wrong threads frames). However, when just trying to 71 identify a dummy-frame that shouldn't matter. The wost that can 72 happen is that a thread is marked as sitting in a dummy frame when, 73 in reality, its corrupted its stack, to the point that a PC is 74 pointing into a dummy frame. */ 75 76 extern int pc_in_dummy_frame (CORE_ADDR pc); 77 78 /* Return the regcache that belongs to the dummy-frame identifed by PC 79 and FP, or NULL if no such frame exists. */ 80 /* FIXME: cagney/2002-11-08: The function only exists because of 81 deprecated_generic_get_saved_register. Eliminate that function and 82 this, to, can go. */ 83 84 extern struct regcache *deprecated_find_dummy_frame_regcache (CORE_ADDR pc, 85 CORE_ADDR fp); 86 #endif /* !defined (DUMMY_FRAME_H) */ 87