| 1 | /* Cache and manage the values of registers for GDB, the GNU debugger. |
| 2 | Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, 2001 |
| 3 | 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 | #include "defs.h" |
| 23 | #include "frame.h" |
| 24 | #include "target.h" |
| 25 | #include "value.h" |
| 26 | #include "inferior.h" /* for inferior_ptid */ |
| 27 | #include "regcache.h" |
| 28 | |
| 29 | /* FIND_SAVED_REGISTER () |
| 30 | |
| 31 | Return the address in which frame FRAME's value of register REGNUM |
| 32 | has been saved in memory. Or return zero if it has not been saved. |
| 33 | If REGNUM specifies the SP, the value we return is actually |
| 34 | the SP value, not an address where it was saved. */ |
| 35 | |
| 36 | CORE_ADDR |
| 37 | find_saved_register (struct frame_info *frame, int regnum) |
| 38 | { |
| 39 | register struct frame_info *frame1 = NULL; |
| 40 | register CORE_ADDR addr = 0; |
| 41 | |
| 42 | if (frame == NULL) /* No regs saved if want current frame */ |
| 43 | return 0; |
| 44 | |
| 45 | #ifdef HAVE_REGISTER_WINDOWS |
| 46 | /* We assume that a register in a register window will only be saved |
| 47 | in one place (since the name changes and/or disappears as you go |
| 48 | towards inner frames), so we only call get_frame_saved_regs on |
| 49 | the current frame. This is directly in contradiction to the |
| 50 | usage below, which assumes that registers used in a frame must be |
| 51 | saved in a lower (more interior) frame. This change is a result |
| 52 | of working on a register window machine; get_frame_saved_regs |
| 53 | always returns the registers saved within a frame, within the |
| 54 | context (register namespace) of that frame. */ |
| 55 | |
| 56 | /* However, note that we don't want this to return anything if |
| 57 | nothing is saved (if there's a frame inside of this one). Also, |
| 58 | callers to this routine asking for the stack pointer want the |
| 59 | stack pointer saved for *this* frame; this is returned from the |
| 60 | next frame. */ |
| 61 | |
| 62 | if (REGISTER_IN_WINDOW_P (regnum)) |
| 63 | { |
| 64 | frame1 = get_next_frame (frame); |
| 65 | if (!frame1) |
| 66 | return 0; /* Registers of this frame are active. */ |
| 67 | |
| 68 | /* Get the SP from the next frame in; it will be this |
| 69 | current frame. */ |
| 70 | if (regnum != SP_REGNUM) |
| 71 | frame1 = frame; |
| 72 | |
| 73 | FRAME_INIT_SAVED_REGS (frame1); |
| 74 | return frame1->saved_regs[regnum]; /* ... which might be zero */ |
| 75 | } |
| 76 | #endif /* HAVE_REGISTER_WINDOWS */ |
| 77 | |
| 78 | /* Note that this next routine assumes that registers used in |
| 79 | frame x will be saved only in the frame that x calls and |
| 80 | frames interior to it. This is not true on the sparc, but the |
| 81 | above macro takes care of it, so we should be all right. */ |
| 82 | while (1) |
| 83 | { |
| 84 | QUIT; |
| 85 | frame1 = get_prev_frame (frame1); |
| 86 | if (frame1 == 0 || frame1 == frame) |
| 87 | break; |
| 88 | FRAME_INIT_SAVED_REGS (frame1); |
| 89 | if (frame1->saved_regs[regnum]) |
| 90 | addr = frame1->saved_regs[regnum]; |
| 91 | } |
| 92 | |
| 93 | return addr; |
| 94 | } |
| 95 | |
| 96 | /* DEFAULT_GET_SAVED_REGISTER () |
| 97 | |
| 98 | Find register number REGNUM relative to FRAME and put its (raw, |
| 99 | target format) contents in *RAW_BUFFER. Set *OPTIMIZED if the |
| 100 | variable was optimized out (and thus can't be fetched). Set *LVAL |
| 101 | to lval_memory, lval_register, or not_lval, depending on whether |
| 102 | the value was fetched from memory, from a register, or in a strange |
| 103 | and non-modifiable way (e.g. a frame pointer which was calculated |
| 104 | rather than fetched). Set *ADDRP to the address, either in memory |
| 105 | on as a REGISTER_BYTE offset into the registers array. |
| 106 | |
| 107 | Note that this implementation never sets *LVAL to not_lval. But |
| 108 | it can be replaced by defining GET_SAVED_REGISTER and supplying |
| 109 | your own. |
| 110 | |
| 111 | The argument RAW_BUFFER must point to aligned memory. */ |
| 112 | |
| 113 | static void |
| 114 | default_get_saved_register (char *raw_buffer, |
| 115 | int *optimized, |
| 116 | CORE_ADDR *addrp, |
| 117 | struct frame_info *frame, |
| 118 | int regnum, |
| 119 | enum lval_type *lval) |
| 120 | { |
| 121 | CORE_ADDR addr; |
| 122 | |
| 123 | if (!target_has_registers) |
| 124 | error ("No registers."); |
| 125 | |
| 126 | /* Normal systems don't optimize out things with register numbers. */ |
| 127 | if (optimized != NULL) |
| 128 | *optimized = 0; |
| 129 | addr = find_saved_register (frame, regnum); |
| 130 | if (addr != 0) |
| 131 | { |
| 132 | if (lval != NULL) |
| 133 | *lval = lval_memory; |
| 134 | if (regnum == SP_REGNUM) |
| 135 | { |
| 136 | if (raw_buffer != NULL) |
| 137 | { |
| 138 | /* Put it back in target format. */ |
| 139 | store_address (raw_buffer, REGISTER_RAW_SIZE (regnum), |
| 140 | (LONGEST) addr); |
| 141 | } |
| 142 | if (addrp != NULL) |
| 143 | *addrp = 0; |
| 144 | return; |
| 145 | } |
| 146 | if (raw_buffer != NULL) |
| 147 | target_read_memory (addr, raw_buffer, REGISTER_RAW_SIZE (regnum)); |
| 148 | } |
| 149 | else |
| 150 | { |
| 151 | if (lval != NULL) |
| 152 | *lval = lval_register; |
| 153 | addr = REGISTER_BYTE (regnum); |
| 154 | if (raw_buffer != NULL) |
| 155 | read_register_gen (regnum, raw_buffer); |
| 156 | } |
| 157 | if (addrp != NULL) |
| 158 | *addrp = addr; |
| 159 | } |
| 160 | |
| 161 | #if !defined (GET_SAVED_REGISTER) |
| 162 | #define GET_SAVED_REGISTER(raw_buffer, optimized, addrp, frame, regnum, lval) \ |
| 163 | default_get_saved_register(raw_buffer, optimized, addrp, frame, regnum, lval) |
| 164 | #endif |
| 165 | |
| 166 | void |
| 167 | get_saved_register (char *raw_buffer, |
| 168 | int *optimized, |
| 169 | CORE_ADDR *addrp, |
| 170 | struct frame_info *frame, |
| 171 | int regnum, |
| 172 | enum lval_type *lval) |
| 173 | { |
| 174 | GET_SAVED_REGISTER (raw_buffer, optimized, addrp, frame, regnum, lval); |
| 175 | } |
| 176 | |
| 177 | /* READ_RELATIVE_REGISTER_RAW_BYTES_FOR_FRAME |
| 178 | |
| 179 | Copy the bytes of register REGNUM, relative to the input stack frame, |
| 180 | into our memory at MYADDR, in target byte order. |
| 181 | The number of bytes copied is REGISTER_RAW_SIZE (REGNUM). |
| 182 | |
| 183 | Returns 1 if could not be read, 0 if could. */ |
| 184 | |
| 185 | /* FIXME: This function increases the confusion between FP_REGNUM |
| 186 | and the virtual/pseudo-frame pointer. */ |
| 187 | |
| 188 | static int |
| 189 | read_relative_register_raw_bytes_for_frame (int regnum, |
| 190 | char *myaddr, |
| 191 | struct frame_info *frame) |
| 192 | { |
| 193 | int optim; |
| 194 | if (regnum == FP_REGNUM && frame) |
| 195 | { |
| 196 | /* Put it back in target format. */ |
| 197 | store_address (myaddr, REGISTER_RAW_SIZE (FP_REGNUM), |
| 198 | (LONGEST) FRAME_FP (frame)); |
| 199 | |
| 200 | return 0; |
| 201 | } |
| 202 | |
| 203 | get_saved_register (myaddr, &optim, (CORE_ADDR *) NULL, frame, |
| 204 | regnum, (enum lval_type *) NULL); |
| 205 | |
| 206 | if (register_cached (regnum) < 0) |
| 207 | return 1; /* register value not available */ |
| 208 | |
| 209 | return optim; |
| 210 | } |
| 211 | |
| 212 | /* READ_RELATIVE_REGISTER_RAW_BYTES |
| 213 | |
| 214 | Copy the bytes of register REGNUM, relative to the current stack |
| 215 | frame, into our memory at MYADDR, in target byte order. |
| 216 | The number of bytes copied is REGISTER_RAW_SIZE (REGNUM). |
| 217 | |
| 218 | Returns 1 if could not be read, 0 if could. */ |
| 219 | |
| 220 | int |
| 221 | read_relative_register_raw_bytes (int regnum, char *myaddr) |
| 222 | { |
| 223 | return read_relative_register_raw_bytes_for_frame (regnum, myaddr, |
| 224 | selected_frame); |
| 225 | } |