Files
binutils-gdb/gdb/m68k-bsd-tdep.c
Simon Marchi a2e3cce344 gdb/solib: C++ify solib_ops
Convert solib_ops into an abstract base class (with abstract methods,
some of them with default implementations) and convert all the existing
solib_ops instances to solib_ops derived classes / implementations.

Prior to this patch, solib_ops is a structure holding function pointers,
of which there are only a handful of global instances (in the
`solib-*.c` files).  When passing an `solib_ops *` around, it's a
pointer to one of these instances.  After this patch, there are no more
global solib_ops instances.  Instances are created as needed and stored
in struct program_space.  These instances could eventually be made to
contain the program space-specific data, which is currently kept in
per-program space registries (I have some pending patches for that).

Prior to this patch, `gdbarch_so_ops` is a gdbarch method that returns a
pointer to the appropriate solib_ops implementation for the gdbarch.
This is replaced with the `gdbarch_make_solib_ops` method, which returns
a new instance of the appropriate solib_ops implementation for this
gdbarch.  This requires introducing some factory functions for the
various solib_ops implementation, to be used as `gdbarch_make_solib_ops`
callbacks.  For instance:

    solib_ops_up
    make_linux_ilp32_svr4_solib_ops ()
    {
      return std::make_unique<linux_ilp32_svr4_solib_ops> ();
    }

The previous code is full of cases of tdep files copying some base
solib_ops implementation, and overriding one or more function pointer
(see ppc_linux_init_abi, for instance).  I tried to convert all of this
is a class hierarchy.  I like that it's now possible to get a good
static view of all the existing solib_ops variants.  The hierarchy looks
like this:

    solib_ops
    ├── aix_solib_ops
    ├── darwin_solib_ops
    ├── dsbt_solib_ops
    ├── frv_solib_ops
    ├── rocm_solib_ops
    ├── svr4_solib_ops
    │   ├── ilp32_svr4_solib_ops
    │   ├── lp64_svr4_solib_ops
    │   ├── linux_ilp32_svr4_solib_ops
    │   │   ├── mips_linux_ilp32_svr4_solib_ops
    │   │   └── ppc_linux_ilp32_svr4_solib_ops
    │   ├── linux_lp64_svr4_solib_ops
    │   │   └── mips_linux_lp64_svr4_solib_ops
    │   ├── mips_nbsd_ilp32_svr4_solib_ops
    │   ├── mips_nbsd_lp64_svr4_solib_ops
    │   ├── mips_fbsd_ilp32_svr4_solib_ops
    │   └── mips_fbsd_lp64_svr4_solib_ops
    └── target_solib_ops
        └── windows_solib_ops

The solib-svr4 code has per-arch specialization to provide a
link_map_offsets, containing the offsets of the interesting fields in
`struct link_map` on that particular architecture.  Prior to this patch,
arches would set a callback returning the appropriate link_map_offsets
by calling `set_solib_svr4_fetch_link_map_offsets`, which also happened
to set the gdbarch's so_ops to `&svr_so_ops`.  I converted this to an
abstract virtual method of `struct svr4_solib_ops`, meaning that all
classes deriving from svr4_solib_ops must provide a method returning the
appropriate link_map_offsets for the architecture.  I renamed
`set_solib_svr4_fetch_link_map_offsets` to `set_solib_svr4_ops`.  This
function is still necessary because it also calls
set_gdbarch_iterate_over_objfiles_in_search_order, but if it was not for
that, we could get rid of it.

There is an instance of CRTP in mips-linux-tdep.c, because both
mips_linux_ilp32_svr4_solib_ops and mips_linux_lp64_svr4_solib_ops need
to derive from different SVR4 base classes (linux_ilp32_svr4_solib_ops
and linux_lp64_svr4_solib_ops), but they both want to override the
in_dynsym_resolve_code method with the same implementation.

The solib_ops::supports_namespaces method is new: the support for
namespaces was previously predicated by the presence or absence of a
find_solib_ns method.  It now needs to be explicit.

There is a new progspace::release_solib_ops method, which is only needed
for rocm_solib_ops.  For the moment, rocm_solib_ops replaces and wraps
the existing svr4_solib_ops instance, in order to combine the results of
the two.  The plan is to have a subsequent patch to allow program spaces to have
multiple solib_ops, removing the need for release_solib_ops.

Speaking of rocm_solib_ops: it previously overrode only a few methods by
copying svr4_solib_ops and overwriting some function pointers.  Now, it
needs to implement all the methods that svr4_solib_ops implements, in
order to forward the call.  Otherwise, the default solib_ops method
would be called, hiding the svr4_solib_ops implementation.  Again, this
can be removed once we have support for multiple solib_ops in a
program_space.

There is also a small change in how rocm_solib_ops is activated.  Prior
to this patch, it's done at the end of rocm_update_solib_list.  Since it
overrides the function pointer in the static svr4_solib_ops, and then
overwrites the host gdbarch, so_ops field, it's something that happens
only once.  After the patch though, we need to set rocm_solib_ops in all
the program spaces that appear.  We do this in
rocm_solib_target_inferior_created and in the new
rocm_solib_target_inferior_execd.  After this, I will explore doing a
change where rocm_solib_ops is only set when we detect the ROCm runtime
is loaded.

Change-Id: I5896b5bcbf8bdb024d67980380feba1ffefaa4c9
Approved-By: Pedro Alves <pedro@palves.net>
2025-06-26 14:08:31 -04:00

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/* Target-dependent code for Motorola 68000 BSD's.
Copyright (C) 2004-2025 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 "arch-utils.h"
#include "frame.h"
#include "osabi.h"
#include "regcache.h"
#include "regset.h"
#include "trad-frame.h"
#include "tramp-frame.h"
#include "gdbtypes.h"
#include "m68k-tdep.h"
#include "solib-svr4.h"
/* Core file support. */
/* Sizeof `struct reg' in <machine/reg.h>. */
#define M68KBSD_SIZEOF_GREGS (18 * 4)
/* Sizeof `struct fpreg' in <machine/reg.h. */
#define M68KBSD_SIZEOF_FPREGS (((8 * 3) + 3) * 4)
int
m68kbsd_fpreg_offset (struct gdbarch *gdbarch, int regnum)
{
int fp_len = gdbarch_register_type (gdbarch, regnum)->length ();
if (regnum >= M68K_FPC_REGNUM)
return 8 * fp_len + (regnum - M68K_FPC_REGNUM) * 4;
return (regnum - M68K_FP0_REGNUM) * fp_len;
}
/* Supply register REGNUM from the buffer specified by FPREGS and LEN
in the floating-point register set REGSET to register cache
REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
static void
m68kbsd_supply_fpregset (const struct regset *regset,
struct regcache *regcache,
int regnum, const void *fpregs, size_t len)
{
struct gdbarch *gdbarch = regcache->arch ();
const gdb_byte *regs = (const gdb_byte *) fpregs;
int i;
gdb_assert (len >= M68KBSD_SIZEOF_FPREGS);
for (i = M68K_FP0_REGNUM; i <= M68K_PC_REGNUM; i++)
{
if (regnum == i || regnum == -1)
regcache->raw_supply (i, regs + m68kbsd_fpreg_offset (gdbarch, i));
}
}
/* Supply register REGNUM from the buffer specified by GREGS and LEN
in the general-purpose register set REGSET to register cache
REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
static void
m68kbsd_supply_gregset (const struct regset *regset,
struct regcache *regcache,
int regnum, const void *gregs, size_t len)
{
const gdb_byte *regs = (const gdb_byte *) gregs;
int i;
gdb_assert (len >= M68KBSD_SIZEOF_GREGS);
for (i = M68K_D0_REGNUM; i <= M68K_PC_REGNUM; i++)
{
if (regnum == i || regnum == -1)
regcache->raw_supply (i, regs + i * 4);
}
if (len >= M68KBSD_SIZEOF_GREGS + M68KBSD_SIZEOF_FPREGS)
{
regs += M68KBSD_SIZEOF_GREGS;
len -= M68KBSD_SIZEOF_GREGS;
m68kbsd_supply_fpregset (regset, regcache, regnum, regs, len);
}
}
/* Motorola 68000 register sets. */
static const struct regset m68kbsd_gregset =
{
NULL,
m68kbsd_supply_gregset,
NULL,
REGSET_VARIABLE_SIZE
};
static const struct regset m68kbsd_fpregset =
{
NULL,
m68kbsd_supply_fpregset
};
/* Iterate over core file register note sections. */
static void
m68kbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
iterate_over_regset_sections_cb *cb,
void *cb_data,
const struct regcache *regcache)
{
cb (".reg", M68KBSD_SIZEOF_GREGS, M68KBSD_SIZEOF_GREGS, &m68kbsd_gregset,
NULL, cb_data);
cb (".reg2", M68KBSD_SIZEOF_FPREGS, M68KBSD_SIZEOF_FPREGS, &m68kbsd_fpregset,
NULL, cb_data);
}
static void
m68kbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
m68k_gdbarch_tdep *tdep = gdbarch_tdep<m68k_gdbarch_tdep> (gdbarch);
tdep->jb_pc = 5;
tdep->jb_elt_size = 4;
set_gdbarch_decr_pc_after_break (gdbarch, 2);
set_gdbarch_iterate_over_regset_sections
(gdbarch, m68kbsd_iterate_over_regset_sections);
/* NetBSD ELF uses the SVR4 ABI. */
m68k_svr4_init_abi (info, gdbarch);
tdep->struct_return = pcc_struct_return;
/* NetBSD ELF uses SVR4-style shared libraries. */
set_solib_svr4_ops (gdbarch, make_svr4_ilp32_solib_ops);
}
INIT_GDB_FILE (m68kbsd_tdep)
{
gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_NETBSD,
m68kbsd_init_abi);
}