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binutils-gdb/gdb/amd64-fbsd-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

344 lines
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/* Target-dependent code for FreeBSD/amd64.
Copyright (C) 2003-2025 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 "osabi.h"
#include "regset.h"
#include "target.h"
#include "trad-frame.h"
#include "tramp-frame.h"
#include "i386-fbsd-tdep.h"
#include "gdbsupport/x86-xstate.h"
#include "amd64-tdep.h"
#include "amd64-fbsd-tdep.h"
#include "fbsd-tdep.h"
#include "solib-svr4.h"
#include "inferior.h"
/* The general-purpose regset consists of 22 64-bit slots, most of
which contain individual registers, but a few contain multiple
16-bit segment registers. */
#define AMD64_FBSD_SIZEOF_GREGSET (22 * 8)
/* The segment base register set consists of 2 64-bit registers. */
#define AMD64_FBSD_SIZEOF_SEGBASES_REGSET (2 * 8)
/* Register maps. */
static const struct regcache_map_entry amd64_fbsd_gregmap[] =
{
{ 1, AMD64_R15_REGNUM, 0 },
{ 1, AMD64_R14_REGNUM, 0 },
{ 1, AMD64_R13_REGNUM, 0 },
{ 1, AMD64_R12_REGNUM, 0 },
{ 1, AMD64_R11_REGNUM, 0 },
{ 1, AMD64_R10_REGNUM, 0 },
{ 1, AMD64_R9_REGNUM, 0 },
{ 1, AMD64_R8_REGNUM, 0 },
{ 1, AMD64_RDI_REGNUM, 0 },
{ 1, AMD64_RSI_REGNUM, 0 },
{ 1, AMD64_RBP_REGNUM, 0 },
{ 1, AMD64_RBX_REGNUM, 0 },
{ 1, AMD64_RDX_REGNUM, 0 },
{ 1, AMD64_RCX_REGNUM, 0 },
{ 1, AMD64_RAX_REGNUM, 0 },
{ 1, REGCACHE_MAP_SKIP, 4 }, /* trapno */
{ 1, AMD64_FS_REGNUM, 2 },
{ 1, AMD64_GS_REGNUM, 2 },
{ 1, REGCACHE_MAP_SKIP, 4 }, /* err */
{ 1, AMD64_ES_REGNUM, 2 },
{ 1, AMD64_DS_REGNUM, 2 },
{ 1, AMD64_RIP_REGNUM, 0 },
{ 1, AMD64_CS_REGNUM, 8 },
{ 1, AMD64_EFLAGS_REGNUM, 8 },
{ 1, AMD64_RSP_REGNUM, 0 },
{ 1, AMD64_SS_REGNUM, 8 },
{ 0 }
};
static const struct regcache_map_entry amd64_fbsd_segbases_regmap[] =
{
{ 1, AMD64_FSBASE_REGNUM, 0 },
{ 1, AMD64_GSBASE_REGNUM, 0 },
{ 0 }
};
/* This layout including fsbase and gsbase was adopted in FreeBSD
8.0. */
static const struct regcache_map_entry amd64_fbsd_mcregmap[] =
{
{ 1, REGCACHE_MAP_SKIP, 8 }, /* mc_onstack */
{ 1, AMD64_RDI_REGNUM, 0 },
{ 1, AMD64_RSI_REGNUM, 0 },
{ 1, AMD64_RDX_REGNUM, 0 },
{ 1, AMD64_RCX_REGNUM, 0 },
{ 1, AMD64_R8_REGNUM, 0 },
{ 1, AMD64_R9_REGNUM, 0 },
{ 1, AMD64_RAX_REGNUM, 0 },
{ 1, AMD64_RBX_REGNUM, 0 },
{ 1, AMD64_RBP_REGNUM, 0 },
{ 1, AMD64_R10_REGNUM, 0 },
{ 1, AMD64_R11_REGNUM, 0 },
{ 1, AMD64_R12_REGNUM, 0 },
{ 1, AMD64_R13_REGNUM, 0 },
{ 1, AMD64_R14_REGNUM, 0 },
{ 1, AMD64_R15_REGNUM, 0 },
{ 1, REGCACHE_MAP_SKIP, 4 }, /* mc_trapno */
{ 1, AMD64_FS_REGNUM, 2 },
{ 1, AMD64_GS_REGNUM, 2 },
{ 1, REGCACHE_MAP_SKIP, 8 }, /* mc_addr */
{ 1, REGCACHE_MAP_SKIP, 4 }, /* mc_flags */
{ 1, AMD64_ES_REGNUM, 2 },
{ 1, AMD64_DS_REGNUM, 2 },
{ 1, REGCACHE_MAP_SKIP, 8 }, /* mc_err */
{ 1, AMD64_RIP_REGNUM, 0 },
{ 1, AMD64_CS_REGNUM, 8 },
{ 1, AMD64_EFLAGS_REGNUM, 8 },
{ 1, AMD64_RSP_REGNUM, 0 },
{ 1, AMD64_SS_REGNUM, 8 },
{ 1, REGCACHE_MAP_SKIP, 8 }, /* mc_len */
{ 1, REGCACHE_MAP_SKIP, 8 }, /* mc_fpformat */
{ 1, REGCACHE_MAP_SKIP, 8 }, /* mc_ownedfp */
{ 64, REGCACHE_MAP_SKIP, 8 }, /* mc_fpstate */
{ 1, AMD64_FSBASE_REGNUM, 0 },
{ 1, AMD64_GSBASE_REGNUM, 0 },
{ 0 }
};
/* Register set definitions. */
const struct regset amd64_fbsd_gregset =
{
amd64_fbsd_gregmap, regcache_supply_regset, regcache_collect_regset
};
const struct regset amd64_fbsd_segbases_regset =
{
amd64_fbsd_segbases_regmap, regcache_supply_regset, regcache_collect_regset
};
/* Support for signal handlers. */
/* In a signal frame, rsp points to a 'struct sigframe' which is
defined as:
struct sigframe {
union {
__siginfohandler_t *sf_action;
__sighandler_t *sf_handler;
} sf_ahu;
ucontext_t sf_uc;
...
}
ucontext_t is defined as:
struct __ucontext {
sigset_t uc_sigmask;
mcontext_t uc_mcontext;
...
};
The mcontext_t contains the general purpose register set as well
as the floating point or XSAVE state. */
/* NB: There is an 8 byte padding hole between sf_ahu and sf_uc. */
#define AMD64_SIGFRAME_UCONTEXT_OFFSET 16
#define AMD64_UCONTEXT_MCONTEXT_OFFSET 16
#define AMD64_SIZEOF_MCONTEXT_T 800
/* Implement the "init" method of struct tramp_frame. */
static void
amd64_fbsd_sigframe_init (const struct tramp_frame *self,
const frame_info_ptr &this_frame,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
CORE_ADDR sp = get_frame_register_unsigned (this_frame, AMD64_RSP_REGNUM);
CORE_ADDR mcontext_addr
= (sp
+ AMD64_SIGFRAME_UCONTEXT_OFFSET
+ AMD64_UCONTEXT_MCONTEXT_OFFSET);
trad_frame_set_reg_regmap (this_cache, amd64_fbsd_mcregmap, mcontext_addr,
AMD64_SIZEOF_MCONTEXT_T);
/* Don't bother with floating point or XSAVE state for now. The
current helper routines for parsing FXSAVE and XSAVE state only
work with regcaches. This could perhaps create a temporary
regcache, collect the register values from mc_fpstate and
mc_xfpustate, and then set register values in the trad_frame. */
trad_frame_set_id (this_cache, frame_id_build (sp, func));
}
static const struct tramp_frame amd64_fbsd_sigframe =
{
SIGTRAMP_FRAME,
1,
{
{0x48, ULONGEST_MAX}, /* lea SIGF_UC(%rsp),%rdi */
{0x8d, ULONGEST_MAX},
{0x7c, ULONGEST_MAX},
{0x24, ULONGEST_MAX},
{0x10, ULONGEST_MAX},
{0x6a, ULONGEST_MAX}, /* pushq $0 */
{0x00, ULONGEST_MAX},
{0x48, ULONGEST_MAX}, /* movq $SYS_sigreturn,%rax */
{0xc7, ULONGEST_MAX},
{0xc0, ULONGEST_MAX},
{0xa1, ULONGEST_MAX},
{0x01, ULONGEST_MAX},
{0x00, ULONGEST_MAX},
{0x00, ULONGEST_MAX},
{0x0f, ULONGEST_MAX}, /* syscall */
{0x05, ULONGEST_MAX},
{TRAMP_SENTINEL_INSN, ULONGEST_MAX}
},
amd64_fbsd_sigframe_init
};
/* Implement the core_read_description gdbarch method. */
static const struct target_desc *
amd64fbsd_core_read_description (struct gdbarch *gdbarch,
struct target_ops *target,
bfd *abfd)
{
x86_xsave_layout layout;
uint64_t xcr0 = i386_fbsd_core_read_xsave_info (abfd, layout);
if (xcr0 == 0)
xcr0 = X86_XSTATE_SSE_MASK;
return amd64_target_description (xcr0, true);
}
/* Similar to amd64_supply_fpregset, but use XSAVE extended state. */
static void
amd64fbsd_supply_xstateregset (const struct regset *regset,
struct regcache *regcache, int regnum,
const void *xstateregs, size_t len)
{
amd64_supply_xsave (regcache, regnum, xstateregs);
}
/* Similar to amd64_collect_fpregset, but use XSAVE extended state. */
static void
amd64fbsd_collect_xstateregset (const struct regset *regset,
const struct regcache *regcache,
int regnum, void *xstateregs, size_t len)
{
amd64_collect_xsave (regcache, regnum, xstateregs, 1);
}
static const struct regset amd64fbsd_xstateregset =
{
NULL,
amd64fbsd_supply_xstateregset,
amd64fbsd_collect_xstateregset
};
/* Iterate over core file register note sections. */
static void
amd64fbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
iterate_over_regset_sections_cb *cb,
void *cb_data,
const struct regcache *regcache)
{
i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
cb (".reg", AMD64_FBSD_SIZEOF_GREGSET, AMD64_FBSD_SIZEOF_GREGSET,
&amd64_fbsd_gregset, NULL, cb_data);
cb (".reg2", tdep->sizeof_fpregset, tdep->sizeof_fpregset, &amd64_fpregset,
NULL, cb_data);
cb (".reg-x86-segbases", AMD64_FBSD_SIZEOF_SEGBASES_REGSET,
AMD64_FBSD_SIZEOF_SEGBASES_REGSET, &amd64_fbsd_segbases_regset,
"segment bases", cb_data);
if (tdep->xsave_layout.sizeof_xsave != 0)
cb (".reg-xstate", tdep->xsave_layout.sizeof_xsave,
tdep->xsave_layout.sizeof_xsave, &amd64fbsd_xstateregset,
"XSAVE extended state", cb_data);
}
/* Implement the get_thread_local_address gdbarch method. */
static CORE_ADDR
amd64fbsd_get_thread_local_address (struct gdbarch *gdbarch, ptid_t ptid,
CORE_ADDR lm_addr, CORE_ADDR offset)
{
regcache *regcache
= get_thread_arch_regcache (current_inferior (), ptid, gdbarch);
target_fetch_registers (regcache, AMD64_FSBASE_REGNUM);
ULONGEST fsbase;
if (regcache->cooked_read (AMD64_FSBASE_REGNUM, &fsbase) != REG_VALID)
error (_("Unable to fetch %%fsbase"));
CORE_ADDR dtv_addr = fsbase + gdbarch_ptr_bit (gdbarch) / 8;
return fbsd_get_thread_local_address (gdbarch, dtv_addr, lm_addr, offset);
}
static void
amd64fbsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (gdbarch);
/* Generic FreeBSD support. */
fbsd_init_abi (info, gdbarch);
/* Obviously FreeBSD is BSD-based. */
i386bsd_init_abi (info, gdbarch);
amd64_init_abi (info, gdbarch,
amd64_target_description (X86_XSTATE_SSE_MASK, true));
tramp_frame_prepend_unwinder (gdbarch, &amd64_fbsd_sigframe);
tdep->xsave_xcr0_offset = I386_FBSD_XSAVE_XCR0_OFFSET;
set_gdbarch_core_read_x86_xsave_layout
(gdbarch, i386_fbsd_core_read_x86_xsave_layout);
/* Iterate over core file register note sections. */
set_gdbarch_iterate_over_regset_sections
(gdbarch, amd64fbsd_iterate_over_regset_sections);
set_gdbarch_core_read_description (gdbarch,
amd64fbsd_core_read_description);
/* FreeBSD uses SVR4-style shared libraries. */
set_solib_svr4_ops (gdbarch, make_svr4_lp64_solib_ops);
set_gdbarch_fetch_tls_load_module_address (gdbarch,
svr4_fetch_objfile_link_map);
set_gdbarch_get_thread_local_address (gdbarch,
amd64fbsd_get_thread_local_address);
}
INIT_GDB_FILE (amd64fbsd_tdep)
{
gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
GDB_OSABI_FREEBSD, amd64fbsd_init_abi);
}
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