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a2e3cce344
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>
99 lines
2.4 KiB
C
99 lines
2.4 KiB
C
/* Target-dependent code for GNU/Linux using SVR4-style libraries.
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Copyright (C) 2025 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "solib-svr4-linux.h"
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/* See solib-svr4-linux.h. */
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solib_ops_up
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make_linux_ilp32_svr4_solib_ops ()
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{
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return std::make_unique<linux_ilp32_svr4_solib_ops> ();
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}
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/* See solib-svr4-linux.h. */
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link_map_offsets *
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linux_ilp32_svr4_solib_ops::fetch_link_map_offsets () const
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{
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static link_map_offsets lmo;
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static link_map_offsets *lmp = nullptr;
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if (lmp == nullptr)
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{
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lmp = &lmo;
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lmo.r_version_offset = 0;
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lmo.r_version_size = 4;
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lmo.r_map_offset = 4;
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lmo.r_brk_offset = 8;
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lmo.r_ldsomap_offset = -1;
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lmo.r_next_offset = 20;
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/* Everything we need is in the first 20 bytes. */
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lmo.link_map_size = 20;
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lmo.l_addr_offset = 0;
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lmo.l_name_offset = 4;
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lmo.l_ld_offset = 8;
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lmo.l_next_offset = 12;
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lmo.l_prev_offset = 16;
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}
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return lmp;
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}
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/* See solib-svr4-linux.h. */
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solib_ops_up
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make_linux_lp64_svr4_solib_ops ()
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{
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return std::make_unique<linux_lp64_svr4_solib_ops> ();
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}
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/* See linux-tdep.h. */
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link_map_offsets *
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linux_lp64_svr4_solib_ops::fetch_link_map_offsets () const
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{
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static link_map_offsets lmo;
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static link_map_offsets *lmp = nullptr;
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if (lmp == nullptr)
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{
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lmp = &lmo;
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lmo.r_version_offset = 0;
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lmo.r_version_size = 4;
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lmo.r_map_offset = 8;
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lmo.r_brk_offset = 16;
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lmo.r_ldsomap_offset = -1;
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lmo.r_next_offset = 40;
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/* Everything we need is in the first 40 bytes. */
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lmo.link_map_size = 40;
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lmo.l_addr_offset = 0;
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lmo.l_name_offset = 8;
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lmo.l_ld_offset = 16;
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lmo.l_next_offset = 24;
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lmo.l_prev_offset = 32;
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}
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return lmp;
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}
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