binutils-gdb/gdb/proc-service.c
Simon Marchi 7438771288 gdb: remove regcache's address space
While looking at the regcache code, I noticed that the address space
(passed to regcache when constructing it, and available through
regcache::aspace) wasn't relevant for the regcache itself.  Callers of
regcache::aspace use that method because it appears to be a convenient
way of getting the address space for a thread, if you already have the
regcache.  But there is always another way to get the address space, as
the callers pretty much always know which thread they are dealing with.
The regcache code itself doesn't use the address space.

This patch removes anything related to address_space from the regcache
code, and updates callers to get it from the thread in context.  This
removes a bit of unnecessary complexity from the regcache code.

The current get_thread_arch_regcache function gets an address_space for
the given thread using the target_thread_address_space function (which
calls the target_ops::thread_address_space method).  This suggest that
there might have been the intention of supporting per-thread address
spaces.  But digging through the history, I did not find any such case.
Maybe this method was just added because we needed a way to get an
address space from a ptid (because constructing a regcache required an
address space), and this seemed like the right way to do it, I don't
know.

The only implementations of thread_address_space and
process_stratum_target::thread_address_space and
linux_nat_target::thread_address_space, which essentially just return
the inferior's address space.  And thread_address_space is only used in
the current get_thread_arch_regcache, which gets removed.  So, I think
that the thread_address_space target method can be removed, and we can
assume that it's fine to use the inferior's address space everywhere.
Callers of regcache::aspace are updated to get the address space from
the relevant inferior, either using some context they already know
about, or in last resort using the current global context.

So, to summarize:

 - remove everything in regcache related to address spaces
 - in particular, remove get_thread_arch_regcache, and rename
   get_thread_arch_aspace_regcache to get_thread_arch_regcache
 - remove target_ops::thread_address_space, and
   target_thread_address_space
 - adjust all users of regcache::aspace to get the address space another
   way

Change-Id: I04fd41b22c83fe486522af7851c75bcfb31c88c7
2023-11-17 20:01:35 +00:00

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/* <proc_service.h> implementation.
Copyright (C) 1999-2023 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 3 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, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "gdbcore.h"
#include "inferior.h"
#include "gdbthread.h"
#include "symtab.h"
#include "target.h"
#include "regcache.h"
#include "objfiles.h"
#include "gdb_proc_service.h"
#include <sys/procfs.h>
/* Prototypes for supply_gregset etc. */
#include "gregset.h"
/* Helper functions. */
/* Convert a psaddr_t to a CORE_ADDR. */
static CORE_ADDR
ps_addr_to_core_addr (psaddr_t addr)
{
if (current_program_space->exec_bfd ()
&& bfd_get_sign_extend_vma (current_program_space->exec_bfd ()))
return (intptr_t) addr;
else
return (uintptr_t) addr;
}
/* Convert a CORE_ADDR to a psaddr_t. */
static psaddr_t
core_addr_to_ps_addr (CORE_ADDR addr)
{
if (current_program_space->exec_bfd ()
&& bfd_get_sign_extend_vma (current_program_space->exec_bfd ()))
return (psaddr_t) (intptr_t) addr;
else
return (psaddr_t) (uintptr_t) addr;
}
/* Transfer LEN bytes of memory between BUF and address ADDR in the
process specified by PH. If WRITE, transfer them to the process,
else transfer them from the process. Returns PS_OK for success,
PS_ERR on failure.
This is a helper function for ps_pdread and ps_pdwrite. */
static ps_err_e
ps_xfer_memory (const struct ps_prochandle *ph, psaddr_t addr,
gdb_byte *buf, size_t len, int write)
{
scoped_restore_current_inferior_for_memory save_inferior (ph->thread->inf);
CORE_ADDR core_addr = ps_addr_to_core_addr (addr);
int ret;
if (write)
ret = target_write_memory (core_addr, buf, len);
else
ret = target_read_memory (core_addr, buf, len);
return (ret == 0 ? PS_OK : PS_ERR);
}
/* Search for the symbol named NAME within the object named OBJ within
the target process PH. If the symbol is found the address of the
symbol is stored in SYM_ADDR. */
ps_err_e
ps_pglobal_lookup (struct ps_prochandle *ph, const char *obj,
const char *name, psaddr_t *sym_addr)
{
inferior *inf = ph->thread->inf;
scoped_restore_current_program_space restore_pspace;
set_current_program_space (inf->pspace);
/* FIXME: kettenis/2000-09-03: What should we do with OBJ? */
bound_minimal_symbol ms = lookup_minimal_symbol (name, NULL, NULL);
if (ms.minsym == NULL)
return PS_NOSYM;
*sym_addr = core_addr_to_ps_addr (ms.value_address ());
return PS_OK;
}
/* Read SIZE bytes from the target process PH at address ADDR and copy
them into BUF. */
ps_err_e
ps_pdread (struct ps_prochandle *ph, psaddr_t addr, void *buf, size_t size)
{
return ps_xfer_memory (ph, addr, (gdb_byte *) buf, size, 0);
}
/* Write SIZE bytes from BUF into the target process PH at address ADDR. */
ps_err_e
ps_pdwrite (struct ps_prochandle *ph, psaddr_t addr,
const void *buf, size_t size)
{
return ps_xfer_memory (ph, addr, (gdb_byte *) buf, size, 1);
}
/* Get a regcache for LWPID using its inferior's "main" architecture,
which is the register set libthread_db expects to be using. In
multi-arch debugging scenarios, the thread's architecture may
differ from the inferior's "main" architecture. */
static struct regcache *
get_ps_regcache (struct ps_prochandle *ph, lwpid_t lwpid)
{
inferior *inf = ph->thread->inf;
return get_thread_arch_regcache (inf, ptid_t (inf->pid, lwpid),
inf->arch ());
}
/* Get the general registers of LWP LWPID within the target process PH
and store them in GREGSET. */
ps_err_e
ps_lgetregs (struct ps_prochandle *ph, lwpid_t lwpid, prgregset_t gregset)
{
struct regcache *regcache = get_ps_regcache (ph, lwpid);
target_fetch_registers (regcache, -1);
fill_gregset (regcache, (gdb_gregset_t *) gregset, -1);
return PS_OK;
}
/* Set the general registers of LWP LWPID within the target process PH
from GREGSET. */
ps_err_e
ps_lsetregs (struct ps_prochandle *ph, lwpid_t lwpid, const prgregset_t gregset)
{
struct regcache *regcache = get_ps_regcache (ph, lwpid);
supply_gregset (regcache, (const gdb_gregset_t *) gregset);
target_store_registers (regcache, -1);
return PS_OK;
}
/* Get the floating-point registers of LWP LWPID within the target
process PH and store them in FPREGSET. */
ps_err_e
ps_lgetfpregs (struct ps_prochandle *ph, lwpid_t lwpid,
prfpregset_t *fpregset)
{
struct regcache *regcache = get_ps_regcache (ph, lwpid);
target_fetch_registers (regcache, -1);
fill_fpregset (regcache, (gdb_fpregset_t *) fpregset, -1);
return PS_OK;
}
/* Set the floating-point registers of LWP LWPID within the target
process PH from FPREGSET. */
ps_err_e
ps_lsetfpregs (struct ps_prochandle *ph, lwpid_t lwpid,
const prfpregset_t *fpregset)
{
struct regcache *regcache = get_ps_regcache (ph, lwpid);
supply_fpregset (regcache, (const gdb_fpregset_t *) fpregset);
target_store_registers (regcache, -1);
return PS_OK;
}
/* Return overall process id of the target PH. Special for GNU/Linux
-- not used on Solaris. */
pid_t
ps_getpid (struct ps_prochandle *ph)
{
return ph->thread->ptid.pid ();
}
void _initialize_proc_service ();
void
_initialize_proc_service ()
{
/* This function solely exists to make sure this module is linked
into the final binary. */
}