From 32178cabe9d82d333ad4274fadb37418da4fb8d1 Mon Sep 17 00:00:00 2001 From: Michael Snyder Date: Mon, 10 Jul 2000 06:16:51 +0000 Subject: 2000-07-07 Michael Snyder * findvar.c (_initialize_findvar, build_findvar, write_fp, read_fp, generic_target_write_fp, generic_target_read_fp, write_sp, read_sp, generic_target_write_sp, generic_target_read_sp, write_pc, read_pc, generic_target_write_pc, generic_target_read_pc, write_pc_pid, read_pc_pid, supply_register, write_register_pid, write_register, read_register_pid, read_register, write_register_bytes, read_register_bytes, write_register_gen, read_register_gen, registers_fetched, registers_changed, find_saved_register, read_relative_register_raw_bytes, default_get_saved_register, read_relative_register_raw_bytes_for_frame, get_saved_register): Move from this file into new file regcache.c. (register_valid, registers_pid, registers): Ditto. * regcache.c: New file to hold the register cache. (register_cached): New function to read register_valid array. * value.h (register_cached): Declare. * defs.h (default_get_saved_register): Delete decl of static function. * Makefile.in: Add regcache module. --- gdb/regcache.c | 840 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 840 insertions(+) (limited to 'gdb/regcache.c') diff --git a/gdb/regcache.c b/gdb/regcache.c index e69de29..3cfafa8 100644 --- a/gdb/regcache.c +++ b/gdb/regcache.c @@ -0,0 +1,840 @@ +/* Cache and manage the values of registers for GDB, the GNU debugger. + Copyright 1986, 87, 89, 91, 94, 95, 96, 1998, 2000 + 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 "inferior.h" +#include "target.h" +#include "gdbarch.h" + +/* + * DATA STRUCTURE + * + * Here is the actual register cache. + */ + +/* NOTE: this is a write-back cache. There is no "dirty" bit for + recording if the register values have been changed (eg. by the + user). Therefore all registers must be written back to the + target when appropriate. */ + +/* REGISTERS contains the cached register values (in target byte order). */ + +char *registers; + +/* REGISTER_VALID is 0 if the register needs to be fetched, + 1 if it has been fetched, and + -1 if the register value was not available. + "Not available" means don't try to fetch it again. */ + +signed char *register_valid; + +/* The thread/process associated with the current set of registers. + For now, -1 is special, and means `no current process'. */ + +static int registers_pid = -1; + +/* + * FUNCTIONS: + */ + +/* REGISTER_CACHED() + + Returns 0 if the value is not in the cache (needs fetch). + >0 if the value is in the cache. + <0 if the value is permanently unavailable (don't ask again). */ + +int +register_cached (int regnum) +{ + return register_valid[regnum]; +} + +/* 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; + +#ifdef HAVE_REGISTER_WINDOWS + /* We assume that a register in a register window will only be saved + in one place (since the name changes and/or disappears as you go + towards inner frames), so we only call get_frame_saved_regs on + the current frame. This is directly in contradiction to the + usage below, which assumes that registers used in a frame must be + saved in a lower (more interior) frame. This change is a result + of working on a register window machine; get_frame_saved_regs + always returns the registers saved within a frame, within the + context (register namespace) of that frame. */ + + /* However, note that we don't want this to return anything if + nothing is saved (if there's a frame inside of this one). Also, + callers to this routine asking for the stack pointer want the + stack pointer saved for *this* frame; this is returned from the + next frame. */ + + if (REGISTER_IN_WINDOW_P (regnum)) + { + frame1 = get_next_frame (frame); + if (!frame1) + return 0; /* Registers of this frame are active. */ + + /* Get the SP from the next frame in; it will be this + current frame. */ + if (regnum != SP_REGNUM) + frame1 = frame; + + FRAME_INIT_SAVED_REGS (frame1); + return frame1->saved_regs[regnum]; /* ... which might be zero */ + } +#endif /* HAVE_REGISTER_WINDOWS */ + + /* Note that this next routine assumes that registers used in + frame x will be saved only in the frame that x calls and + frames interior to it. This is not true on the sparc, but the + above macro takes care of it, so we should be all right. */ + while (1) + { + QUIT; + frame1 = get_prev_frame (frame1); + if (frame1 == 0 || frame1 == frame) + break; + FRAME_INIT_SAVED_REGS (frame1); + if (frame1->saved_regs[regnum]) + addr = frame1->saved_regs[regnum]; + } + + return addr; +} + +/* DEFAULT_GET_SAVED_REGISTER () + + Find register number REGNUM relative to FRAME and put its (raw, + target format) contents in *RAW_BUFFER. Set *OPTIMIZED if the + variable was optimized out (and thus can't be fetched). Set *LVAL + to lval_memory, lval_register, or not_lval, depending on whether + the value was fetched from memory, from a register, or in a strange + and non-modifiable way (e.g. a frame pointer which was calculated + rather than fetched). Set *ADDRP to the address, either in memory + on as a REGISTER_BYTE offset into the registers array. + + Note that this implementation never sets *LVAL to not_lval. But + it can be replaced by defining GET_SAVED_REGISTER and supplying + your own. + + The argument RAW_BUFFER must point to aligned memory. */ + +static void +default_get_saved_register (char *raw_buffer, + int *optimized, + CORE_ADDR *addrp, + struct frame_info *frame, + int regnum, + enum lval_type *lval) +{ + CORE_ADDR addr; + + if (!target_has_registers) + error ("No registers."); + + /* Normal systems don't optimize out things with register numbers. */ + if (optimized != NULL) + *optimized = 0; + addr = find_saved_register (frame, regnum); + if (addr != 0) + { + if (lval != NULL) + *lval = lval_memory; + if (regnum == SP_REGNUM) + { + if (raw_buffer != NULL) + { + /* Put it back in target format. */ + store_address (raw_buffer, REGISTER_RAW_SIZE (regnum), + (LONGEST) addr); + } + if (addrp != NULL) + *addrp = 0; + return; + } + if (raw_buffer != NULL) + target_read_memory (addr, raw_buffer, REGISTER_RAW_SIZE (regnum)); + } + else + { + if (lval != NULL) + *lval = lval_register; + addr = REGISTER_BYTE (regnum); + if (raw_buffer != NULL) + read_register_gen (regnum, raw_buffer); + } + if (addrp != NULL) + *addrp = addr; +} + +#if !defined (GET_SAVED_REGISTER) +#define GET_SAVED_REGISTER(raw_buffer, optimized, addrp, frame, regnum, lval) \ + default_get_saved_register(raw_buffer, optimized, addrp, frame, regnum, lval) +#endif + +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); +} + +/* READ_RELATIVE_REGISTER_RAW_BYTES_FOR_FRAME + + Copy the bytes of register REGNUM, relative to the input stack frame, + into our memory at MYADDR, in target byte order. + The number of bytes copied is REGISTER_RAW_SIZE (REGNUM). + + Returns 1 if could not be read, 0 if could. */ + +/* FIXME: This function increases the confusion between FP_REGNUM + and the virtual/pseudo-frame pointer. */ + +static int +read_relative_register_raw_bytes_for_frame (int regnum, + char *myaddr, + struct frame_info *frame) +{ + int optim; + if (regnum == FP_REGNUM && frame) + { + /* Put it back in target format. */ + store_address (myaddr, REGISTER_RAW_SIZE (FP_REGNUM), + (LONGEST) FRAME_FP (frame)); + + return 0; + } + + get_saved_register (myaddr, &optim, (CORE_ADDR *) NULL, frame, + regnum, (enum lval_type *) NULL); + + if (register_valid[regnum] < 0) + return 1; /* register value not available */ + + return optim; +} + +/* READ_RELATIVE_REGISTER_RAW_BYTES + + Copy the bytes of register REGNUM, relative to the current stack + frame, into our memory at MYADDR, in target byte order. + The number of bytes copied is REGISTER_RAW_SIZE (REGNUM). + + Returns 1 if could not be read, 0 if could. */ + +int +read_relative_register_raw_bytes (int regnum, char *myaddr) +{ + return read_relative_register_raw_bytes_for_frame (regnum, myaddr, + selected_frame); +} + + +/* Low level examining and depositing of registers. + + The caller is responsible for making sure that the inferior is + stopped before calling the fetching routines, or it will get + garbage. (a change from GDB version 3, in which the caller got the + value from the last stop). */ + +/* REGISTERS_CHANGED () + + Indicate that registers may have changed, so invalidate the cache. */ + +void +registers_changed (void) +{ + int i; + int numregs = ARCH_NUM_REGS; + + registers_pid = -1; + + /* Force cleanup of any alloca areas if using C alloca instead of + a builtin alloca. This particular call is used to clean up + areas allocated by low level target code which may build up + during lengthy interactions between gdb and the target before + gdb gives control to the user (ie watchpoints). */ + alloca (0); + + for (i = 0; i < numregs; i++) + register_valid[i] = 0; + + if (registers_changed_hook) + registers_changed_hook (); +} + +/* REGISTERS_FETCHED () + + Indicate that all registers have been fetched, so mark them all valid. */ + + +void +registers_fetched (void) +{ + int i; + int numregs = ARCH_NUM_REGS; + + for (i = 0; i < numregs; i++) + register_valid[i] = 1; +} + +/* read_register_bytes and write_register_bytes are generally a *BAD* + idea. They are inefficient because they need to check for partial + updates, which can only be done by scanning through all of the + registers and seeing if the bytes that are being read/written fall + inside of an invalid register. [The main reason this is necessary + is that register sizes can vary, so a simple index won't suffice.] + It is far better to call read_register_gen and write_register_gen + if you want to get at the raw register contents, as it only takes a + regno as an argument, and therefore can't do a partial register + update. + + Prior to the recent fixes to check for partial updates, both read + and write_register_bytes always checked to see if any registers + were stale, and then called target_fetch_registers (-1) to update + the whole set. This caused really slowed things down for remote + targets. */ + +/* Copy INLEN bytes of consecutive data from registers + starting with the INREGBYTE'th byte of register data + into memory at MYADDR. */ + +void +read_register_bytes (int inregbyte, char *myaddr, int inlen) +{ + int inregend = inregbyte + inlen; + int regno; + + if (registers_pid != inferior_pid) + { + registers_changed (); + registers_pid = inferior_pid; + } + + /* See if we are trying to read bytes from out-of-date registers. If so, + update just those registers. */ + + for (regno = 0; regno < NUM_REGS; regno++) + { + int regstart, regend; + + if (register_valid[regno]) + continue; + + if (REGISTER_NAME (regno) == NULL || *REGISTER_NAME (regno) == '\0') + continue; + + regstart = REGISTER_BYTE (regno); + regend = regstart + REGISTER_RAW_SIZE (regno); + + if (regend <= inregbyte || inregend <= regstart) + /* The range the user wants to read doesn't overlap with regno. */ + continue; + + /* We've found an invalid register where at least one byte will be read. + Update it from the target. */ + target_fetch_registers (regno); + + if (!register_valid[regno]) + error ("read_register_bytes: Couldn't update register %d.", regno); + } + + if (myaddr != NULL) + memcpy (myaddr, ®isters[inregbyte], inlen); +} + +/* Read register REGNO into memory at MYADDR, which must be large + enough for REGISTER_RAW_BYTES (REGNO). Target byte-order. If the + register is known to be the size of a CORE_ADDR or smaller, + read_register can be used instead. */ + +void +read_register_gen (int regno, char *myaddr) +{ + if (registers_pid != inferior_pid) + { + registers_changed (); + registers_pid = inferior_pid; + } + + if (!register_valid[regno]) + target_fetch_registers (regno); + memcpy (myaddr, ®isters[REGISTER_BYTE (regno)], + REGISTER_RAW_SIZE (regno)); +} + +/* Write register REGNO at MYADDR to the target. MYADDR points at + REGISTER_RAW_BYTES(REGNO), which must be in target byte-order. */ + +/* Registers we shouldn't try to store. */ +#if !defined (CANNOT_STORE_REGISTER) +#define CANNOT_STORE_REGISTER(regno) 0 +#endif + +void +write_register_gen (int regno, char *myaddr) +{ + int size; + + /* On the sparc, writing %g0 is a no-op, so we don't even want to + change the registers array if something writes to this register. */ + if (CANNOT_STORE_REGISTER (regno)) + return; + + if (registers_pid != inferior_pid) + { + registers_changed (); + registers_pid = inferior_pid; + } + + size = REGISTER_RAW_SIZE (regno); + + /* If we have a valid copy of the register, and new value == old value, + then don't bother doing the actual store. */ + + if (register_valid[regno] + && memcmp (®isters[REGISTER_BYTE (regno)], myaddr, size) == 0) + return; + + target_prepare_to_store (); + + memcpy (®isters[REGISTER_BYTE (regno)], myaddr, size); + + register_valid[regno] = 1; + + target_store_registers (regno); +} + +/* Copy INLEN bytes of consecutive data from memory at MYADDR + into registers starting with the MYREGSTART'th byte of register data. */ + +void +write_register_bytes (int myregstart, char *myaddr, int inlen) +{ + int myregend = myregstart + inlen; + int regno; + + target_prepare_to_store (); + + /* Scan through the registers updating any that are covered by the + range myregstart<=>myregend using write_register_gen, which does + nice things like handling threads, and avoiding updates when the + new and old contents are the same. */ + + for (regno = 0; regno < NUM_REGS; regno++) + { + int regstart, regend; + + regstart = REGISTER_BYTE (regno); + regend = regstart + REGISTER_RAW_SIZE (regno); + + /* Is this register completely outside the range the user is writing? */ + if (myregend <= regstart || regend <= myregstart) + /* do nothing */ ; + + /* Is this register completely within the range the user is writing? */ + else if (myregstart <= regstart && regend <= myregend) + write_register_gen (regno, myaddr + (regstart - myregstart)); + + /* The register partially overlaps the range being written. */ + else + { + char regbuf[MAX_REGISTER_RAW_SIZE]; + /* What's the overlap between this register's bytes and + those the caller wants to write? */ + int overlapstart = max (regstart, myregstart); + int overlapend = min (regend, myregend); + + /* We may be doing a partial update of an invalid register. + Update it from the target before scribbling on it. */ + read_register_gen (regno, regbuf); + + memcpy (registers + overlapstart, + myaddr + (overlapstart - myregstart), + overlapend - overlapstart); + + target_store_registers (regno); + } + } +} + + +/* Return the raw contents of register REGNO, regarding it as an + integer. This probably should be returning LONGEST rather than + CORE_ADDR. */ + +CORE_ADDR +read_register (int regno) +{ + if (registers_pid != inferior_pid) + { + registers_changed (); + registers_pid = inferior_pid; + } + + if (!register_valid[regno]) + target_fetch_registers (regno); + + return ((CORE_ADDR) + extract_unsigned_integer (®isters[REGISTER_BYTE (regno)], + REGISTER_RAW_SIZE (regno))); +} + +CORE_ADDR +read_register_pid (int regno, int pid) +{ + int save_pid; + CORE_ADDR retval; + + if (pid == inferior_pid) + return read_register (regno); + + save_pid = inferior_pid; + + inferior_pid = pid; + + retval = read_register (regno); + + inferior_pid = save_pid; + + return retval; +} + +/* Store VALUE, into the raw contents of register number REGNO. */ + +void +write_register (int regno, LONGEST val) +{ + PTR buf; + int size; + + /* On the sparc, writing %g0 is a no-op, so we don't even want to + change the registers array if something writes to this register. */ + if (CANNOT_STORE_REGISTER (regno)) + return; + + if (registers_pid != inferior_pid) + { + registers_changed (); + registers_pid = inferior_pid; + } + + size = REGISTER_RAW_SIZE (regno); + buf = alloca (size); + store_signed_integer (buf, size, (LONGEST) val); + + /* If we have a valid copy of the register, and new value == old value, + then don't bother doing the actual store. */ + + if (register_valid[regno] + && memcmp (®isters[REGISTER_BYTE (regno)], buf, size) == 0) + return; + + target_prepare_to_store (); + + memcpy (®isters[REGISTER_BYTE (regno)], buf, size); + + register_valid[regno] = 1; + + target_store_registers (regno); +} + +void +write_register_pid (int regno, CORE_ADDR val, int pid) +{ + int save_pid; + + if (pid == inferior_pid) + { + write_register (regno, val); + return; + } + + save_pid = inferior_pid; + + inferior_pid = pid; + + write_register (regno, val); + + inferior_pid = save_pid; +} + +/* SUPPLY_REGISTER() + + Record that register REGNO contains VAL. This is used when the + value is obtained from the inferior or core dump, so there is no + need to store the value there. + + If VAL is a NULL pointer, then it's probably an unsupported register. + We just set it's value to all zeros. We might want to record this + fact, and report it to the users of read_register and friends. */ + +void +supply_register (int regno, char *val) +{ +#if 1 + if (registers_pid != inferior_pid) + { + registers_changed (); + registers_pid = inferior_pid; + } +#endif + + register_valid[regno] = 1; + if (val) + memcpy (®isters[REGISTER_BYTE (regno)], val, + REGISTER_RAW_SIZE (regno)); + else + memset (®isters[REGISTER_BYTE (regno)], '\000', + REGISTER_RAW_SIZE (regno)); + + /* On some architectures, e.g. HPPA, there are a few stray bits in + some registers, that the rest of the code would like to ignore. */ + +#ifdef CLEAN_UP_REGISTER_VALUE + CLEAN_UP_REGISTER_VALUE (regno, ®isters[REGISTER_BYTE (regno)]); +#endif +} + +/* read_pc, write_pc, read_sp, write_sp, read_fp, write_fp, etc. + Special handling for registers PC, SP, and FP. */ + +/* This routine is getting awfully cluttered with #if's. It's probably + time to turn this into READ_PC and define it in the tm.h file. + Ditto for write_pc. + + 1999-06-08: The following were re-written so that it assumes the + existance of a TARGET_READ_PC et.al. macro. A default generic + version of that macro is made available where needed. + + Since the ``TARGET_READ_PC'' et.al. macro is going to be controlled + by the multi-arch framework, it will eventually be possible to + eliminate the intermediate read_pc_pid(). The client would call + TARGET_READ_PC directly. (cagney). */ + +#ifndef TARGET_READ_PC +#define TARGET_READ_PC generic_target_read_pc +#endif + +CORE_ADDR +generic_target_read_pc (int pid) +{ +#ifdef PC_REGNUM + if (PC_REGNUM >= 0) + { + CORE_ADDR pc_val = ADDR_BITS_REMOVE ((CORE_ADDR) read_register_pid (PC_REGNUM, pid)); + return pc_val; + } +#endif + internal_error ("generic_target_read_pc"); + return 0; +} + +CORE_ADDR +read_pc_pid (int pid) +{ + int saved_inferior_pid; + CORE_ADDR pc_val; + + /* In case pid != inferior_pid. */ + saved_inferior_pid = inferior_pid; + inferior_pid = pid; + + pc_val = TARGET_READ_PC (pid); + + inferior_pid = saved_inferior_pid; + return pc_val; +} + +CORE_ADDR +read_pc (void) +{ + return read_pc_pid (inferior_pid); +} + +#ifndef TARGET_WRITE_PC +#define TARGET_WRITE_PC generic_target_write_pc +#endif + +void +generic_target_write_pc (CORE_ADDR pc, int pid) +{ +#ifdef PC_REGNUM + if (PC_REGNUM >= 0) + write_register_pid (PC_REGNUM, pc, pid); + if (NPC_REGNUM >= 0) + write_register_pid (NPC_REGNUM, pc + 4, pid); + if (NNPC_REGNUM >= 0) + write_register_pid (NNPC_REGNUM, pc + 8, pid); +#else + internal_error ("generic_target_write_pc"); +#endif +} + +void +write_pc_pid (CORE_ADDR pc, int pid) +{ + int saved_inferior_pid; + + /* In case pid != inferior_pid. */ + saved_inferior_pid = inferior_pid; + inferior_pid = pid; + + TARGET_WRITE_PC (pc, pid); + + inferior_pid = saved_inferior_pid; +} + +void +write_pc (CORE_ADDR pc) +{ + write_pc_pid (pc, inferior_pid); +} + +/* Cope with strage ways of getting to the stack and frame pointers */ + +#ifndef TARGET_READ_SP +#define TARGET_READ_SP generic_target_read_sp +#endif + +CORE_ADDR +generic_target_read_sp (void) +{ +#ifdef SP_REGNUM + if (SP_REGNUM >= 0) + return read_register (SP_REGNUM); +#endif + internal_error ("generic_target_read_sp"); +} + +CORE_ADDR +read_sp (void) +{ + return TARGET_READ_SP (); +} + +#ifndef TARGET_WRITE_SP +#define TARGET_WRITE_SP generic_target_write_sp +#endif + +void +generic_target_write_sp (CORE_ADDR val) +{ +#ifdef SP_REGNUM + if (SP_REGNUM >= 0) + { + write_register (SP_REGNUM, val); + return; + } +#endif + internal_error ("generic_target_write_sp"); +} + +void +write_sp (CORE_ADDR val) +{ + TARGET_WRITE_SP (val); +} + +#ifndef TARGET_READ_FP +#define TARGET_READ_FP generic_target_read_fp +#endif + +CORE_ADDR +generic_target_read_fp (void) +{ +#ifdef FP_REGNUM + if (FP_REGNUM >= 0) + return read_register (FP_REGNUM); +#endif + internal_error ("generic_target_read_fp"); +} + +CORE_ADDR +read_fp (void) +{ + return TARGET_READ_FP (); +} + +#ifndef TARGET_WRITE_FP +#define TARGET_WRITE_FP generic_target_write_fp +#endif + +void +generic_target_write_fp (CORE_ADDR val) +{ +#ifdef FP_REGNUM + if (FP_REGNUM >= 0) + { + write_register (FP_REGNUM, val); + return; + } +#endif + internal_error ("generic_target_write_fp"); +} + +void +write_fp (CORE_ADDR val) +{ + TARGET_WRITE_FP (val); +} + +static void +build_regcache (void) +{ + /* We allocate some extra slop since we do a lot of memcpy's around + `registers', and failing-soft is better than failing hard. */ + int sizeof_registers = REGISTER_BYTES + /* SLOP */ 256; + int sizeof_register_valid = NUM_REGS * sizeof (*register_valid); + registers = xmalloc (sizeof_registers); + memset (registers, 0, sizeof_registers); + register_valid = xmalloc (sizeof_register_valid); + memset (register_valid, 0, sizeof_register_valid); +} + +void +_initialize_regcache (void) +{ + build_regcache (); + + register_gdbarch_swap (®isters, sizeof (registers), NULL); + register_gdbarch_swap (®ister_valid, sizeof (register_valid), NULL); + register_gdbarch_swap (NULL, 0, build_regcache); +} -- cgit v1.1