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binutils-gdb/gdb/alpha-linux-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

393 lines
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/* Target-dependent code for GNU/Linux on Alpha.
Copyright (C) 2002-2025 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 "frame.h"
#include "solib-svr4-linux.h"
#include "osabi.h"
#include "solib-svr4.h"
#include "symtab.h"
#include "regset.h"
#include "regcache.h"
#include "linux-tdep.h"
#include "alpha-tdep.h"
#include "gdbarch.h"
/* This enum represents the signals' numbers on the Alpha
architecture. It just contains the signal definitions which are
different from the generic implementation.
It is derived from the file <arch/alpha/include/uapi/asm/signal.h>,
from the Linux kernel tree. */
enum
{
/* SIGABRT is the same as in the generic implementation, but is
defined here because SIGIOT depends on it. */
ALPHA_LINUX_SIGABRT = 6,
ALPHA_LINUX_SIGEMT = 7,
ALPHA_LINUX_SIGBUS = 10,
ALPHA_LINUX_SIGSYS = 12,
ALPHA_LINUX_SIGURG = 16,
ALPHA_LINUX_SIGSTOP = 17,
ALPHA_LINUX_SIGTSTP = 18,
ALPHA_LINUX_SIGCONT = 19,
ALPHA_LINUX_SIGCHLD = 20,
ALPHA_LINUX_SIGIO = 23,
ALPHA_LINUX_SIGINFO = 29,
ALPHA_LINUX_SIGUSR1 = 30,
ALPHA_LINUX_SIGUSR2 = 31,
ALPHA_LINUX_SIGPOLL = ALPHA_LINUX_SIGIO,
ALPHA_LINUX_SIGPWR = ALPHA_LINUX_SIGINFO,
ALPHA_LINUX_SIGIOT = ALPHA_LINUX_SIGABRT,
};
/* Under GNU/Linux, signal handler invocations can be identified by
the designated code sequence that is used to return from a signal
handler. In particular, the return address of a signal handler
points to a sequence that copies $sp to $16, loads $0 with the
appropriate syscall number, and finally enters the kernel.
This is somewhat complicated in that:
(1) the expansion of the "mov" assembler macro has changed over
time, from "bis src,src,dst" to "bis zero,src,dst",
(2) the kernel has changed from using "addq" to "lda" to load the
syscall number,
(3) there is a "normal" sigreturn and an "rt" sigreturn which
has a different stack layout. */
static long
alpha_linux_sigtramp_offset_1 (struct gdbarch *gdbarch, CORE_ADDR pc)
{
switch (alpha_read_insn (gdbarch, pc))
{
case 0x47de0410: /* bis $30,$30,$16 */
case 0x47fe0410: /* bis $31,$30,$16 */
return 0;
case 0x43ecf400: /* addq $31,103,$0 */
case 0x201f0067: /* lda $0,103($31) */
case 0x201f015f: /* lda $0,351($31) */
return 4;
case 0x00000083: /* call_pal callsys */
return 8;
default:
return -1;
}
}
static LONGEST
alpha_linux_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc)
{
long i, off;
if (pc & 3)
return -1;
/* Guess where we might be in the sequence. */
off = alpha_linux_sigtramp_offset_1 (gdbarch, pc);
if (off < 0)
return -1;
/* Verify that the other two insns of the sequence are as we expect. */
pc -= off;
for (i = 0; i < 12; i += 4)
{
if (i == off)
continue;
if (alpha_linux_sigtramp_offset_1 (gdbarch, pc + i) != i)
return -1;
}
return off;
}
static int
alpha_linux_pc_in_sigtramp (struct gdbarch *gdbarch,
CORE_ADDR pc, const char *func_name)
{
return alpha_linux_sigtramp_offset (gdbarch, pc) >= 0;
}
static CORE_ADDR
alpha_linux_sigcontext_addr (const frame_info_ptr &this_frame)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
CORE_ADDR pc;
ULONGEST sp;
long off;
pc = get_frame_pc (this_frame);
sp = get_frame_register_unsigned (this_frame, ALPHA_SP_REGNUM);
off = alpha_linux_sigtramp_offset (gdbarch, pc);
gdb_assert (off >= 0);
/* __NR_rt_sigreturn has a couple of structures on the stack. This is:
struct rt_sigframe {
struct siginfo info;
struct ucontext uc;
};
offsetof (struct rt_sigframe, uc.uc_mcontext); */
if (alpha_read_insn (gdbarch, pc - off + 4) == 0x201f015f)
return sp + 176;
/* __NR_sigreturn has the sigcontext structure at the top of the stack. */
return sp;
}
/* 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
alpha_linux_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;
gdb_assert (len >= 32 * 8);
alpha_supply_int_regs (regcache, regnum, regs, regs + 31 * 8,
len >= 33 * 8 ? regs + 32 * 8 : NULL);
}
/* Collect register REGNUM from the register cache REGCACHE and store
it in the buffer specified by GREGS and LEN as described by the
general-purpose register set REGSET. If REGNUM is -1, do this for
all registers in REGSET. */
static void
alpha_linux_collect_gregset (const struct regset *regset,
const struct regcache *regcache,
int regnum, void *gregs, size_t len)
{
gdb_byte *regs = (gdb_byte *) gregs;
gdb_assert (len >= 32 * 8);
alpha_fill_int_regs (regcache, regnum, regs, regs + 31 * 8,
len >= 33 * 8 ? regs + 32 * 8 : NULL);
}
/* 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
alpha_linux_supply_fpregset (const struct regset *regset,
struct regcache *regcache,
int regnum, const void *fpregs, size_t len)
{
const gdb_byte *regs = (const gdb_byte *) fpregs;
gdb_assert (len >= 32 * 8);
alpha_supply_fp_regs (regcache, regnum, regs, regs + 31 * 8);
}
/* Collect register REGNUM from the register cache REGCACHE and store
it in the buffer specified by FPREGS and LEN as described by the
general-purpose register set REGSET. If REGNUM is -1, do this for
all registers in REGSET. */
static void
alpha_linux_collect_fpregset (const struct regset *regset,
const struct regcache *regcache,
int regnum, void *fpregs, size_t len)
{
gdb_byte *regs = (gdb_byte *) fpregs;
gdb_assert (len >= 32 * 8);
alpha_fill_fp_regs (regcache, regnum, regs, regs + 31 * 8);
}
static const struct regset alpha_linux_gregset =
{
NULL,
alpha_linux_supply_gregset, alpha_linux_collect_gregset
};
static const struct regset alpha_linux_fpregset =
{
NULL,
alpha_linux_supply_fpregset, alpha_linux_collect_fpregset
};
/* Iterate over core file register note sections. */
static void
alpha_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
iterate_over_regset_sections_cb *cb,
void *cb_data,
const struct regcache *regcache)
{
cb (".reg", 32 * 8, 32 * 8, &alpha_linux_gregset, NULL, cb_data);
cb (".reg2", 32 * 8, 32 * 8, &alpha_linux_fpregset, NULL, cb_data);
}
/* Implementation of `gdbarch_gdb_signal_from_target', as defined in
gdbarch.h. */
static enum gdb_signal
alpha_linux_gdb_signal_from_target (struct gdbarch *gdbarch,
int signal)
{
switch (signal)
{
case ALPHA_LINUX_SIGEMT:
return GDB_SIGNAL_EMT;
case ALPHA_LINUX_SIGBUS:
return GDB_SIGNAL_BUS;
case ALPHA_LINUX_SIGSYS:
return GDB_SIGNAL_SYS;
case ALPHA_LINUX_SIGURG:
return GDB_SIGNAL_URG;
case ALPHA_LINUX_SIGSTOP:
return GDB_SIGNAL_STOP;
case ALPHA_LINUX_SIGTSTP:
return GDB_SIGNAL_TSTP;
case ALPHA_LINUX_SIGCONT:
return GDB_SIGNAL_CONT;
case ALPHA_LINUX_SIGCHLD:
return GDB_SIGNAL_CHLD;
/* No way to differentiate between SIGIO and SIGPOLL.
Therefore, we just handle the first one. */
case ALPHA_LINUX_SIGIO:
return GDB_SIGNAL_IO;
/* No way to differentiate between SIGINFO and SIGPWR.
Therefore, we just handle the first one. */
case ALPHA_LINUX_SIGINFO:
return GDB_SIGNAL_INFO;
case ALPHA_LINUX_SIGUSR1:
return GDB_SIGNAL_USR1;
case ALPHA_LINUX_SIGUSR2:
return GDB_SIGNAL_USR2;
}
return linux_gdb_signal_from_target (gdbarch, signal);
}
/* Implementation of `gdbarch_gdb_signal_to_target', as defined in
gdbarch.h. */
static int
alpha_linux_gdb_signal_to_target (struct gdbarch *gdbarch,
enum gdb_signal signal)
{
switch (signal)
{
case GDB_SIGNAL_EMT:
return ALPHA_LINUX_SIGEMT;
case GDB_SIGNAL_BUS:
return ALPHA_LINUX_SIGBUS;
case GDB_SIGNAL_SYS:
return ALPHA_LINUX_SIGSYS;
case GDB_SIGNAL_URG:
return ALPHA_LINUX_SIGURG;
case GDB_SIGNAL_STOP:
return ALPHA_LINUX_SIGSTOP;
case GDB_SIGNAL_TSTP:
return ALPHA_LINUX_SIGTSTP;
case GDB_SIGNAL_CONT:
return ALPHA_LINUX_SIGCONT;
case GDB_SIGNAL_CHLD:
return ALPHA_LINUX_SIGCHLD;
case GDB_SIGNAL_IO:
return ALPHA_LINUX_SIGIO;
case GDB_SIGNAL_INFO:
return ALPHA_LINUX_SIGINFO;
case GDB_SIGNAL_USR1:
return ALPHA_LINUX_SIGUSR1;
case GDB_SIGNAL_USR2:
return ALPHA_LINUX_SIGUSR2;
case GDB_SIGNAL_POLL:
return ALPHA_LINUX_SIGPOLL;
case GDB_SIGNAL_PWR:
return ALPHA_LINUX_SIGPWR;
}
return linux_gdb_signal_to_target (gdbarch, signal);
}
static void
alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
linux_init_abi (info, gdbarch, 0);
/* Hook into the DWARF CFI frame unwinder. */
alpha_dwarf2_init_abi (info, gdbarch);
/* Hook into the MDEBUG frame unwinder. */
alpha_mdebug_init_abi (info, gdbarch);
alpha_gdbarch_tdep *tdep = gdbarch_tdep<alpha_gdbarch_tdep> (gdbarch);
tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset;
tdep->sigcontext_addr = alpha_linux_sigcontext_addr;
tdep->pc_in_sigtramp = alpha_linux_pc_in_sigtramp;
tdep->jb_pc = 2;
tdep->jb_elt_size = 8;
set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
set_solib_svr4_ops (gdbarch, make_linux_lp64_svr4_solib_ops);
/* Enable TLS support. */
set_gdbarch_fetch_tls_load_module_address (gdbarch,
svr4_fetch_objfile_link_map);
set_gdbarch_iterate_over_regset_sections
(gdbarch, alpha_linux_iterate_over_regset_sections);
set_gdbarch_gdb_signal_from_target (gdbarch,
alpha_linux_gdb_signal_from_target);
set_gdbarch_gdb_signal_to_target (gdbarch,
alpha_linux_gdb_signal_to_target);
}
INIT_GDB_FILE (alpha_linux_tdep)
{
gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_LINUX,
alpha_linux_init_abi);
}
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