Files
binutils-gdb/gdb/linux-tdep.h
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

117 lines
4.0 KiB
C++

/* Target-dependent code for GNU/Linux, architecture independent.
Copyright (C) 2009-2025 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/>. */
#ifndef GDB_LINUX_TDEP_H
#define GDB_LINUX_TDEP_H
#include "bfd.h"
#include "displaced-stepping.h"
#include "solib.h"
struct inferior;
struct regcache;
/* Enum used to define the extra fields of the siginfo type used by an
architecture. */
enum linux_siginfo_extra_field_values
{
/* Add bound fields into the segmentation fault field. */
LINUX_SIGINFO_FIELD_ADDR_BND = 1
};
/* Defines a type for the values defined in linux_siginfo_extra_field_values. */
DEF_ENUM_FLAGS_TYPE (enum linux_siginfo_extra_field_values,
linux_siginfo_extra_fields);
/* This function is suitable for architectures that
extend/override the standard siginfo in a specific way. */
struct type *linux_get_siginfo_type_with_fields (struct gdbarch *gdbarch,
linux_siginfo_extra_fields);
/* Return true if ADDRESS is within the boundaries of a page mapped with
memory tagging protection. */
bool linux_address_in_memtag_page (CORE_ADDR address);
typedef char *(*linux_collect_thread_registers_ftype) (const struct regcache *,
ptid_t,
bfd *, char *, int *,
enum gdb_signal);
extern enum gdb_signal linux_gdb_signal_from_target (struct gdbarch *gdbarch,
int signal);
extern int linux_gdb_signal_to_target (struct gdbarch *gdbarch,
enum gdb_signal signal);
/* Default GNU/Linux implementation of `displaced_step_location', as
defined in gdbarch.h. Determines the entry point from AT_ENTRY in
the target auxiliary vector. */
extern CORE_ADDR linux_displaced_step_location (struct gdbarch *gdbarch);
/* Implementation of gdbarch_displaced_step_prepare. */
extern displaced_step_prepare_status linux_displaced_step_prepare
(gdbarch *arch, thread_info *thread, CORE_ADDR &displaced_pc);
/* Implementation of gdbarch_displaced_step_finish. */
extern displaced_step_finish_status linux_displaced_step_finish
(gdbarch *arch, thread_info *thread, const target_waitstatus &status);
/* Implementation of gdbarch_displaced_step_copy_insn_closure_by_addr. */
extern const displaced_step_copy_insn_closure *
linux_displaced_step_copy_insn_closure_by_addr
(inferior *inf, CORE_ADDR addr);
/* Implementation of gdbarch_displaced_step_restore_all_in_ptid. */
extern void linux_displaced_step_restore_all_in_ptid (inferior *parent_inf,
ptid_t ptid);
extern void linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch,
int num_disp_step_buffers);
extern int linux_is_uclinux (void);
/* Fetch the AT_HWCAP entry from auxv data AUXV. Use TARGET and GDBARCH to
parse auxv entries.
On error, 0 is returned. */
extern CORE_ADDR linux_get_hwcap (const std::optional<gdb::byte_vector> &auxv,
struct target_ops *target, gdbarch *gdbarch);
/* Same as the above, but obtain all the inputs from the current inferior. */
extern CORE_ADDR linux_get_hwcap ();
/* Fetch the AT_HWCAP2 entry from auxv data AUXV. Use TARGET and GDBARCH to
parse auxv entries.
On error, 0 is returned. */
extern CORE_ADDR linux_get_hwcap2 (const std::optional<gdb::byte_vector> &auxv,
struct target_ops *target, gdbarch *gdbarch);
/* Same as the above, but obtain all the inputs from the current inferior. */
extern CORE_ADDR linux_get_hwcap2 ();
#endif /* GDB_LINUX_TDEP_H */