| 1 | /* Cache and manage the values of registers for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, |
| 4 | 2001, 2002 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "frame.h" |
| 25 | #include "target.h" |
| 26 | #include "value.h" |
| 27 | #include "inferior.h" /* for inferior_ptid */ |
| 28 | #include "regcache.h" |
| 29 | |
| 30 | /* FIND_SAVED_REGISTER () |
| 31 | |
| 32 | Return the address in which frame FRAME's value of register REGNUM |
| 33 | has been saved in memory. Or return zero if it has not been saved. |
| 34 | If REGNUM specifies the SP, the value we return is actually |
| 35 | the SP value, not an address where it was saved. */ |
| 36 | |
| 37 | CORE_ADDR |
| 38 | find_saved_register (struct frame_info *frame, int regnum) |
| 39 | { |
| 40 | register struct frame_info *frame1 = NULL; |
| 41 | register CORE_ADDR addr = 0; |
| 42 | |
| 43 | if (frame == NULL) /* No regs saved if want current frame */ |
| 44 | return 0; |
| 45 | |
| 46 | /* Note that this next routine assumes that registers used in |
| 47 | frame x will be saved only in the frame that x calls and |
| 48 | frames interior to it. This is not true on the sparc, but the |
| 49 | above macro takes care of it, so we should be all right. */ |
| 50 | while (1) |
| 51 | { |
| 52 | QUIT; |
| 53 | frame1 = get_next_frame (frame); |
| 54 | if (frame1 == 0) |
| 55 | break; |
| 56 | frame = frame1; |
| 57 | FRAME_INIT_SAVED_REGS (frame1); |
| 58 | if (frame1->saved_regs[regnum]) |
| 59 | addr = frame1->saved_regs[regnum]; |
| 60 | } |
| 61 | |
| 62 | return addr; |
| 63 | } |
| 64 | |
| 65 | /* DEFAULT_GET_SAVED_REGISTER () |
| 66 | |
| 67 | Find register number REGNUM relative to FRAME and put its (raw, |
| 68 | target format) contents in *RAW_BUFFER. Set *OPTIMIZED if the |
| 69 | variable was optimized out (and thus can't be fetched). Set *LVAL |
| 70 | to lval_memory, lval_register, or not_lval, depending on whether |
| 71 | the value was fetched from memory, from a register, or in a strange |
| 72 | and non-modifiable way (e.g. a frame pointer which was calculated |
| 73 | rather than fetched). Set *ADDRP to the address, either in memory |
| 74 | on as a REGISTER_BYTE offset into the registers array. |
| 75 | |
| 76 | Note that this implementation never sets *LVAL to not_lval. But |
| 77 | it can be replaced by defining GET_SAVED_REGISTER and supplying |
| 78 | your own. |
| 79 | |
| 80 | The argument RAW_BUFFER must point to aligned memory. */ |
| 81 | |
| 82 | static void |
| 83 | default_get_saved_register (char *raw_buffer, |
| 84 | int *optimized, |
| 85 | CORE_ADDR *addrp, |
| 86 | struct frame_info *frame, |
| 87 | int regnum, |
| 88 | enum lval_type *lval) |
| 89 | { |
| 90 | CORE_ADDR addr; |
| 91 | |
| 92 | if (!target_has_registers) |
| 93 | error ("No registers."); |
| 94 | |
| 95 | /* Normal systems don't optimize out things with register numbers. */ |
| 96 | if (optimized != NULL) |
| 97 | *optimized = 0; |
| 98 | addr = find_saved_register (frame, regnum); |
| 99 | if (addr != 0) |
| 100 | { |
| 101 | if (lval != NULL) |
| 102 | *lval = lval_memory; |
| 103 | if (regnum == SP_REGNUM) |
| 104 | { |
| 105 | if (raw_buffer != NULL) |
| 106 | { |
| 107 | /* Put it back in target format. */ |
| 108 | store_address (raw_buffer, REGISTER_RAW_SIZE (regnum), |
| 109 | (LONGEST) addr); |
| 110 | } |
| 111 | if (addrp != NULL) |
| 112 | *addrp = 0; |
| 113 | return; |
| 114 | } |
| 115 | if (raw_buffer != NULL) |
| 116 | target_read_memory (addr, raw_buffer, REGISTER_RAW_SIZE (regnum)); |
| 117 | } |
| 118 | else |
| 119 | { |
| 120 | if (lval != NULL) |
| 121 | *lval = lval_register; |
| 122 | addr = REGISTER_BYTE (regnum); |
| 123 | if (raw_buffer != NULL) |
| 124 | read_register_gen (regnum, raw_buffer); |
| 125 | } |
| 126 | if (addrp != NULL) |
| 127 | *addrp = addr; |
| 128 | } |
| 129 | |
| 130 | #if !defined (GET_SAVED_REGISTER) |
| 131 | #define GET_SAVED_REGISTER(raw_buffer, optimized, addrp, frame, regnum, lval) \ |
| 132 | default_get_saved_register(raw_buffer, optimized, addrp, frame, regnum, lval) |
| 133 | #endif |
| 134 | |
| 135 | void |
| 136 | get_saved_register (char *raw_buffer, |
| 137 | int *optimized, |
| 138 | CORE_ADDR *addrp, |
| 139 | struct frame_info *frame, |
| 140 | int regnum, |
| 141 | enum lval_type *lval) |
| 142 | { |
| 143 | GET_SAVED_REGISTER (raw_buffer, optimized, addrp, frame, regnum, lval); |
| 144 | } |
| 145 | |
| 146 | /* frame_register_read () |
| 147 | |
| 148 | Find and return the value of REGNUM for the specified stack frame. |
| 149 | The number of bytes copied is REGISTER_RAW_SIZE (REGNUM). |
| 150 | |
| 151 | Returns 0 if the register value could not be found. */ |
| 152 | |
| 153 | int |
| 154 | frame_register_read (struct frame_info *frame, int regnum, void *myaddr) |
| 155 | { |
| 156 | int optim; |
| 157 | get_saved_register (myaddr, &optim, (CORE_ADDR *) NULL, frame, |
| 158 | regnum, (enum lval_type *) NULL); |
| 159 | |
| 160 | /* FIXME: cagney/2002-04-10: This test is just bogus. It is no |
| 161 | indication of the validity of the register. The value could |
| 162 | easily be found (on the stack) even though the corresponding |
| 163 | register isn't available. */ |
| 164 | if (register_cached (regnum) < 0) |
| 165 | return 0; /* register value not available */ |
| 166 | |
| 167 | return !optim; |
| 168 | } |