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binutils-gdb/gdb/m68k-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

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/* Motorola m68k target-dependent support for GNU/Linux.
Copyright (C) 1996-2025 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 "extract-store-integer.h"
#include "gdbcore.h"
#include "frame.h"
#include "target.h"
#include "gdbtypes.h"
#include "osabi.h"
#include "regcache.h"
#include "objfiles.h"
#include "symtab.h"
#include "m68k-tdep.h"
#include "trad-frame.h"
#include "frame-unwind.h"
#include "glibc-tdep.h"
#include "solib-svr4.h"
#include "auxv.h"
#include "observable.h"
#include "elf/common.h"
#include "linux-tdep.h"
#include "solib-svr4-linux.h"
#include "regset.h"
/* Offsets (in target ints) into jmp_buf. */
#define M68K_LINUX_JB_ELEMENT_SIZE 4
#define M68K_LINUX_JB_PC 7
/* Check whether insn1 and insn2 are parts of a signal trampoline. */
#define IS_SIGTRAMP(insn1, insn2) \
(/* addaw #20,sp; moveq #119,d0; trap #0 */ \
(insn1 == 0xdefc0014 && insn2 == 0x70774e40) \
/* moveq #119,d0; trap #0 */ \
|| insn1 == 0x70774e40)
#define IS_RT_SIGTRAMP(insn1, insn2) \
(/* movel #173,d0; trap #0 */ \
(insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \
/* moveq #82,d0; notb d0; trap #0 */ \
|| (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40))
/* Return non-zero if THIS_FRAME corresponds to a signal trampoline. For
the sake of m68k_linux_get_sigtramp_info we also distinguish between
non-RT and RT signal trampolines. */
static int
m68k_linux_pc_in_sigtramp (const frame_info_ptr &this_frame)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
gdb_byte buf[12];
unsigned long insn0, insn1, insn2;
CORE_ADDR pc = get_frame_pc (this_frame);
if (!safe_frame_unwind_memory (this_frame, pc - 4, {buf, sizeof (buf)}))
return 0;
insn1 = extract_unsigned_integer (buf + 4, 4, byte_order);
insn2 = extract_unsigned_integer (buf + 8, 4, byte_order);
if (IS_SIGTRAMP (insn1, insn2))
return 1;
if (IS_RT_SIGTRAMP (insn1, insn2))
return 2;
insn0 = extract_unsigned_integer (buf, 4, byte_order);
if (IS_SIGTRAMP (insn0, insn1))
return 1;
if (IS_RT_SIGTRAMP (insn0, insn1))
return 2;
insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16);
insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16);
if (IS_SIGTRAMP (insn0, insn1))
return 1;
if (IS_RT_SIGTRAMP (insn0, insn1))
return 2;
return 0;
}
/* From <asm/sigcontext.h>. */
static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] =
{
2 * 4, /* %d0 */
3 * 4, /* %d1 */
-1, /* %d2 */
-1, /* %d3 */
-1, /* %d4 */
-1, /* %d5 */
-1, /* %d6 */
-1, /* %d7 */
4 * 4, /* %a0 */
5 * 4, /* %a1 */
-1, /* %a2 */
-1, /* %a3 */
-1, /* %a4 */
-1, /* %a5 */
-1, /* %fp */
1 * 4, /* %sp */
6 * 4, /* %sr */
6 * 4 + 2, /* %pc */
8 * 4, /* %fp0 */
11 * 4, /* %fp1 */
-1, /* %fp2 */
-1, /* %fp3 */
-1, /* %fp4 */
-1, /* %fp5 */
-1, /* %fp6 */
-1, /* %fp7 */
14 * 4, /* %fpcr */
15 * 4, /* %fpsr */
16 * 4 /* %fpiaddr */
};
static int m68k_uclinux_sigcontext_reg_offset[M68K_NUM_REGS] =
{
2 * 4, /* %d0 */
3 * 4, /* %d1 */
-1, /* %d2 */
-1, /* %d3 */
-1, /* %d4 */
-1, /* %d5 */
-1, /* %d6 */
-1, /* %d7 */
4 * 4, /* %a0 */
5 * 4, /* %a1 */
-1, /* %a2 */
-1, /* %a3 */
-1, /* %a4 */
6 * 4, /* %a5 */
-1, /* %fp */
1 * 4, /* %sp */
7 * 4, /* %sr */
7 * 4 + 2, /* %pc */
-1, /* %fp0 */
-1, /* %fp1 */
-1, /* %fp2 */
-1, /* %fp3 */
-1, /* %fp4 */
-1, /* %fp5 */
-1, /* %fp6 */
-1, /* %fp7 */
-1, /* %fpcr */
-1, /* %fpsr */
-1 /* %fpiaddr */
};
/* From <asm/ucontext.h>. */
static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] =
{
6 * 4, /* %d0 */
7 * 4, /* %d1 */
8 * 4, /* %d2 */
9 * 4, /* %d3 */
10 * 4, /* %d4 */
11 * 4, /* %d5 */
12 * 4, /* %d6 */
13 * 4, /* %d7 */
14 * 4, /* %a0 */
15 * 4, /* %a1 */
16 * 4, /* %a2 */
17 * 4, /* %a3 */
18 * 4, /* %a4 */
19 * 4, /* %a5 */
20 * 4, /* %fp */
21 * 4, /* %sp */
23 * 4, /* %sr */
22 * 4, /* %pc */
27 * 4, /* %fp0 */
30 * 4, /* %fp1 */
33 * 4, /* %fp2 */
36 * 4, /* %fp3 */
39 * 4, /* %fp4 */
42 * 4, /* %fp5 */
45 * 4, /* %fp6 */
48 * 4, /* %fp7 */
24 * 4, /* %fpcr */
25 * 4, /* %fpsr */
26 * 4 /* %fpiaddr */
};
/* Get info about saved registers in sigtramp. */
struct m68k_linux_sigtramp_info
{
/* Address of sigcontext. */
CORE_ADDR sigcontext_addr;
/* Offset of registers in `struct sigcontext'. */
int *sc_reg_offset;
};
/* Nonzero if running on uClinux. */
static int target_is_uclinux;
static void
m68k_linux_inferior_created (inferior *inf)
{
/* Record that we will need to re-evaluate whether we are running on a
uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */
target_is_uclinux = -1;
}
static struct m68k_linux_sigtramp_info
m68k_linux_get_sigtramp_info (const frame_info_ptr &this_frame)
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
CORE_ADDR sp;
struct m68k_linux_sigtramp_info info;
/* Determine whether we are running on a uClinux or normal GNU/Linux
target so we can use the correct sigcontext layouts. */
if (target_is_uclinux == -1)
target_is_uclinux = linux_is_uclinux ();
sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM);
/* Get sigcontext address, it is the third parameter on the stack. */
info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4, byte_order);
if (m68k_linux_pc_in_sigtramp (this_frame) == 2)
info.sc_reg_offset = m68k_linux_ucontext_reg_offset;
else
info.sc_reg_offset = (target_is_uclinux
? m68k_uclinux_sigcontext_reg_offset
: m68k_linux_sigcontext_reg_offset);
return info;
}
/* Signal trampolines. */
static struct trad_frame_cache *
m68k_linux_sigtramp_frame_cache (const frame_info_ptr &this_frame,
void **this_cache)
{
struct frame_id this_id;
struct trad_frame_cache *cache;
struct gdbarch *gdbarch = get_frame_arch (this_frame);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
struct m68k_linux_sigtramp_info info;
gdb_byte buf[4];
int i;
if (*this_cache)
return (struct trad_frame_cache *) *this_cache;
cache = trad_frame_cache_zalloc (this_frame);
/* FIXME: cagney/2004-05-01: This is is long standing broken code.
The frame ID's code address should be the start-address of the
signal trampoline and not the current PC within that
trampoline. */
get_frame_register (this_frame, M68K_SP_REGNUM, buf);
/* See the end of m68k_push_dummy_call. */
this_id = frame_id_build (extract_unsigned_integer (buf, 4, byte_order)
- 4 + 8, get_frame_pc (this_frame));
trad_frame_set_id (cache, this_id);
info = m68k_linux_get_sigtramp_info (this_frame);
for (i = 0; i < M68K_NUM_REGS; i++)
if (info.sc_reg_offset[i] != -1)
trad_frame_set_reg_addr (cache, i,
info.sigcontext_addr + info.sc_reg_offset[i]);
*this_cache = cache;
return cache;
}
static void
m68k_linux_sigtramp_frame_this_id (const frame_info_ptr &this_frame,
void **this_cache,
struct frame_id *this_id)
{
struct trad_frame_cache *cache =
m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
trad_frame_get_id (cache, this_id);
}
static struct value *
m68k_linux_sigtramp_frame_prev_register (const frame_info_ptr &this_frame,
void **this_cache,
int regnum)
{
/* Make sure we've initialized the cache. */
struct trad_frame_cache *cache =
m68k_linux_sigtramp_frame_cache (this_frame, this_cache);
return trad_frame_get_register (cache, this_frame, regnum);
}
static int
m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
const frame_info_ptr &this_frame,
void **this_prologue_cache)
{
return m68k_linux_pc_in_sigtramp (this_frame);
}
static const struct frame_unwind_legacy m68k_linux_sigtramp_frame_unwind (
"m68k linux sigtramp",
SIGTRAMP_FRAME,
FRAME_UNWIND_ARCH,
default_frame_unwind_stop_reason,
m68k_linux_sigtramp_frame_this_id,
m68k_linux_sigtramp_frame_prev_register,
NULL,
m68k_linux_sigtramp_frame_sniffer
);
/* Register maps for supply/collect regset functions. */
static const struct regcache_map_entry m68k_linux_gregmap[] =
{
{ 7, M68K_D1_REGNUM, 4 }, /* d1 ... d7 */
{ 7, M68K_A0_REGNUM, 4 }, /* a0 ... a6 */
{ 1, M68K_D0_REGNUM, 4 },
{ 1, M68K_SP_REGNUM, 4 },
{ 1, REGCACHE_MAP_SKIP, 4 }, /* orig_d0 (skip) */
{ 1, M68K_PS_REGNUM, 4 },
{ 1, M68K_PC_REGNUM, 4 },
/* Ignore 16-bit fields 'fmtvec' and '__fill'. */
{ 0 }
};
#define M68K_LINUX_GREGS_SIZE (20 * 4)
static const struct regcache_map_entry m68k_linux_fpregmap[] =
{
{ 8, M68K_FP0_REGNUM, 12 }, /* fp0 ... fp7 */
{ 1, M68K_FPC_REGNUM, 4 },
{ 1, M68K_FPS_REGNUM, 4 },
{ 1, M68K_FPI_REGNUM, 4 },
{ 0 }
};
#define M68K_LINUX_FPREGS_SIZE (27 * 4)
/* Register sets. */
static const struct regset m68k_linux_gregset =
{
m68k_linux_gregmap,
regcache_supply_regset, regcache_collect_regset
};
static const struct regset m68k_linux_fpregset =
{
m68k_linux_fpregmap,
regcache_supply_regset, regcache_collect_regset
};
/* Iterate over core file register note sections. */
static void
m68k_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
iterate_over_regset_sections_cb *cb,
void *cb_data,
const struct regcache *regcache)
{
cb (".reg", M68K_LINUX_GREGS_SIZE, M68K_LINUX_GREGS_SIZE, &m68k_linux_gregset,
NULL, cb_data);
cb (".reg2", M68K_LINUX_FPREGS_SIZE, M68K_LINUX_FPREGS_SIZE,
&m68k_linux_fpregset, NULL, cb_data);
}
static void
m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
m68k_gdbarch_tdep *tdep = gdbarch_tdep<m68k_gdbarch_tdep> (gdbarch);
linux_init_abi (info, gdbarch, 0);
tdep->jb_pc = M68K_LINUX_JB_PC;
tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE;
/* GNU/Linux uses a calling convention that's similar to SVR4. It
returns integer values in %d0/%d1, pointer values in %a0 and
floating values in %fp0, just like SVR4, but uses %a1 to pass the
address to store a structure value. It also returns small
structures in registers instead of memory. */
m68k_svr4_init_abi (info, gdbarch);
tdep->struct_value_regnum = M68K_A1_REGNUM;
tdep->struct_return = reg_struct_return;
set_gdbarch_decr_pc_after_break (gdbarch, 2);
frame_unwind_append_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind);
/* Shared library handling. */
/* GNU/Linux uses SVR4-style shared libraries. */
set_solib_svr4_ops (gdbarch, make_linux_ilp32_svr4_solib_ops);
/* GNU/Linux uses the dynamic linker included in the GNU C Library. */
set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver);
set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
/* Core file support. */
set_gdbarch_iterate_over_regset_sections
(gdbarch, m68k_linux_iterate_over_regset_sections);
/* Enable TLS support. */
set_gdbarch_fetch_tls_load_module_address (gdbarch,
svr4_fetch_objfile_link_map);
}
INIT_GDB_FILE (m68k_linux_tdep)
{
gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX,
m68k_linux_init_abi);
gdb::observers::inferior_created.attach (m68k_linux_inferior_created,
"m68k-linux-tdep");
}
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