| /* Cache and manage frames for GDB, the GNU debugger. |
| |
| Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, |
| 2001, 2002 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 2 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, write to the Free Software |
| Foundation, Inc., 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| #include "defs.h" |
| #include "frame.h" |
| #include "target.h" |
| #include "value.h" |
| #include "inferior.h" /* for inferior_ptid */ |
| #include "regcache.h" |
| #include "gdb_assert.h" |
| |
| /* Return a frame uniq ID that can be used to, later re-find the |
| frame. */ |
| |
| void |
| get_frame_id (struct frame_info *fi, struct frame_id *id) |
| { |
| if (fi == NULL) |
| { |
| id->base = 0; |
| id->pc = 0; |
| } |
| else |
| { |
| id->base = FRAME_FP (fi); |
| id->pc = fi->pc; |
| } |
| } |
| |
| struct frame_info * |
| frame_find_by_id (struct frame_id id) |
| { |
| struct frame_info *frame; |
| |
| /* ZERO denotes the null frame, let the caller decide what to do |
| about it. Should it instead return get_current_frame()? */ |
| if (id.base == 0 && id.pc == 0) |
| return NULL; |
| |
| for (frame = get_current_frame (); |
| frame != NULL; |
| frame = get_prev_frame (frame)) |
| { |
| if (INNER_THAN (FRAME_FP (frame), id.base)) |
| /* ``inner/current < frame < id.base''. Keep looking along |
| the frame chain. */ |
| continue; |
| if (INNER_THAN (id.base, FRAME_FP (frame))) |
| /* ``inner/current < id.base < frame''. Oops, gone past it. |
| Just give up. */ |
| return NULL; |
| /* FIXME: cagney/2002-04-21: This isn't sufficient. It should |
| use id.pc to check that the two frames belong to the same |
| function. Otherwise we'll do things like match dummy frames |
| or mis-match frameless functions. However, until someone |
| notices, stick with the existing behavour. */ |
| return frame; |
| } |
| return NULL; |
| } |
| |
| /* FIND_SAVED_REGISTER () |
| |
| Return the address in which frame FRAME's value of register REGNUM |
| has been saved in memory. Or return zero if it has not been saved. |
| If REGNUM specifies the SP, the value we return is actually |
| the SP value, not an address where it was saved. */ |
| |
| CORE_ADDR |
| find_saved_register (struct frame_info *frame, int regnum) |
| { |
| register struct frame_info *frame1 = NULL; |
| register CORE_ADDR addr = 0; |
| |
| if (frame == NULL) /* No regs saved if want current frame */ |
| return 0; |
| |
| /* Note that the following loop assumes that registers used in |
| frame x will be saved only in the frame that x calls and frames |
| interior to it. */ |
| while (1) |
| { |
| QUIT; |
| frame1 = get_next_frame (frame); |
| if (frame1 == 0) |
| break; |
| frame = frame1; |
| FRAME_INIT_SAVED_REGS (frame1); |
| if (frame1->saved_regs[regnum]) |
| { |
| addr = frame1->saved_regs[regnum]; |
| break; |
| } |
| } |
| |
| return addr; |
| } |
| |
| void |
| frame_register_unwind (struct frame_info *frame, int regnum, |
| int *optimizedp, enum lval_type *lvalp, |
| CORE_ADDR *addrp, int *realnump, void *bufferp) |
| { |
| struct frame_unwind_cache *cache; |
| |
| /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates |
| that the value proper does not need to be fetched. */ |
| gdb_assert (optimizedp != NULL); |
| gdb_assert (lvalp != NULL); |
| gdb_assert (addrp != NULL); |
| gdb_assert (realnump != NULL); |
| /* gdb_assert (bufferp != NULL); */ |
| |
| /* NOTE: cagney/2002-04-14: It would be nice if, instead of a |
| special case, there was always an inner frame dedicated to the |
| hardware registers. Unfortunatly, there is too much unwind code |
| around that looks up/down the frame chain while making the |
| assumption that each frame level is using the same unwind code. */ |
| |
| if (frame == NULL) |
| { |
| /* We're in the inner-most frame, get the value direct from the |
| register cache. */ |
| *optimizedp = 0; |
| *lvalp = lval_register; |
| /* ULGH! Code uses the offset into the raw register byte array |
| as a way of identifying a register. */ |
| *addrp = REGISTER_BYTE (regnum); |
| /* Should this code test ``register_cached (regnum) < 0'' and do |
| something like set realnum to -1 when the register isn't |
| available? */ |
| *realnump = regnum; |
| if (bufferp) |
| read_register_gen (regnum, bufferp); |
| return; |
| } |
| |
| /* Ask this frame to unwind its register. */ |
| frame->register_unwind (frame, &frame->register_unwind_cache, regnum, |
| optimizedp, lvalp, addrp, realnump, bufferp); |
| } |
| |
| |
| void |
| generic_unwind_get_saved_register (char *raw_buffer, |
| int *optimizedp, |
| CORE_ADDR *addrp, |
| struct frame_info *frame, |
| int regnum, |
| enum lval_type *lvalp) |
| { |
| int optimizedx; |
| CORE_ADDR addrx; |
| int realnumx; |
| enum lval_type lvalx; |
| |
| if (!target_has_registers) |
| error ("No registers."); |
| |
| /* Keep things simple, ensure that all the pointers (except valuep) |
| are non NULL. */ |
| if (optimizedp == NULL) |
| optimizedp = &optimizedx; |
| if (lvalp == NULL) |
| lvalp = &lvalx; |
| if (addrp == NULL) |
| addrp = &addrx; |
| |
| /* Reached the the bottom (youngest, inner most) of the frame chain |
| (youngest, inner most) frame, go direct to the hardware register |
| cache (do not pass go, do not try to cache the value, ...). The |
| unwound value would have been cached in frame->next but that |
| doesn't exist. This doesn't matter as the hardware register |
| cache is stopping any unnecessary accesses to the target. */ |
| |
| /* NOTE: cagney/2002-04-14: It would be nice if, instead of a |
| special case, there was always an inner frame dedicated to the |
| hardware registers. Unfortunatly, there is too much unwind code |
| around that looks up/down the frame chain while making the |
| assumption that each frame level is using the same unwind code. */ |
| |
| if (frame == NULL) |
| frame_register_unwind (NULL, regnum, optimizedp, lvalp, addrp, &realnumx, |
| raw_buffer); |
| else |
| frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, |
| &realnumx, raw_buffer); |
| } |
| |
| void |
| get_saved_register (char *raw_buffer, |
| int *optimized, |
| CORE_ADDR *addrp, |
| struct frame_info *frame, |
| int regnum, |
| enum lval_type *lval) |
| { |
| GET_SAVED_REGISTER (raw_buffer, optimized, addrp, frame, regnum, lval); |
| } |
| |
| /* frame_register_read () |
| |
| Find and return the value of REGNUM for the specified stack frame. |
| The number of bytes copied is REGISTER_RAW_SIZE (REGNUM). |
| |
| Returns 0 if the register value could not be found. */ |
| |
| int |
| frame_register_read (struct frame_info *frame, int regnum, void *myaddr) |
| { |
| int optim; |
| get_saved_register (myaddr, &optim, (CORE_ADDR *) NULL, frame, |
| regnum, (enum lval_type *) NULL); |
| |
| /* FIXME: cagney/2002-05-15: This test, is just bogus. |
| |
| It indicates that the target failed to supply a value for a |
| register because it was "not available" at this time. Problem |
| is, the target still has the register and so get saved_register() |
| may be returning a value saved on the stack. */ |
| |
| if (register_cached (regnum) < 0) |
| return 0; /* register value not available */ |
| |
| return !optim; |
| } |