gdb: Migrate frame unwinders to use C++ classes

Frame unwinders have historically been a structure populated with
callback pointers, so that architectures (or other specific unwinders)
could install their own way to handle the inferior. However, since
moving to C++, we could use polymorphism to get the same functionality
in a more readable way. Polymorphism also makes it simpler to add new
functionality to all frame unwinders, since all that's required is
adding it to the base class.

As part of the changes to add support to disabling frame unwinders,
this commit makes the first baby step in  using polymorphism for the
frame unwinders, by making frame_unwind a virtual class, and adds a
couple of new classes. The main class added is frame_unwind_legacy,
which works the same as the previous structs, using function pointers
as callbacks. This class was added to allow the transition to happen
piecemeal. New unwinders should instead follow the lead of the other
classes implemented.

2 of the others, frame_unwind_python and frame_unwind_trampoline, were added
because it seemed simpler at the moment to do that instead of reworking
the dynamic allocation to work with the legacy class, and can be used as
an example to future implementations.

Finally, the cygwin unwinder was converted to a class since it was most
of the way there already.

Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>

gdb/aarch64-tdep.c

@@ -1205,8 +1205,7 @@ aarch64_prologue_prev_register (const frame_info_ptr &this_frame,
 }
 
 /* AArch64 prologue unwinder.  */
-static frame_unwind aarch64_prologue_unwind =
+static const frame_unwind_legacy aarch64_prologue_unwind (
-{
   "aarch64 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1215,7 +1214,7 @@ static frame_unwind aarch64_prologue_unwind =
   aarch64_prologue_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Allocate and fill in *THIS_CACHE with information about the prologue of
    *THIS_FRAME.  Do not do this is if *THIS_CACHE was already allocated.
@@ -1301,8 +1300,7 @@ aarch64_stub_unwind_sniffer (const struct frame_unwind *self,
 }
 
 /* AArch64 stub unwinder.  */
-static frame_unwind aarch64_stub_unwind =
+static const frame_unwind_legacy aarch64_stub_unwind (
-{
   "aarch64 stub",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1311,7 +1309,7 @@ static frame_unwind aarch64_stub_unwind =
   aarch64_prologue_prev_register,
   NULL,
   aarch64_stub_unwind_sniffer
-};
+);
 
 /* Return the frame base address of *THIS_FRAME.  */
 

gdb/alpha-mdebug-tdep.c

@@ -330,8 +330,7 @@ alpha_mdebug_frame_sniffer (const struct frame_unwind *self,
   return 1;
 }
 
-static const struct frame_unwind alpha_mdebug_frame_unwind =
+static const struct frame_unwind_legacy alpha_mdebug_frame_unwind (
-{
   "alpha mdebug",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -340,7 +339,7 @@ static const struct frame_unwind alpha_mdebug_frame_unwind =
   alpha_mdebug_frame_prev_register,
   NULL,
   alpha_mdebug_frame_sniffer
-};
+);
 
 static CORE_ADDR
 alpha_mdebug_frame_base_address (const frame_info_ptr &this_frame,

gdb/alpha-tdep.c

@@ -1007,8 +1007,7 @@ alpha_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind alpha_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy alpha_sigtramp_frame_unwind (
-{
   "alpha sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1017,7 +1016,7 @@ static const struct frame_unwind alpha_sigtramp_frame_unwind =
   alpha_sigtramp_frame_prev_register,
   NULL,
   alpha_sigtramp_frame_sniffer
-};
+);
 
 
 
@@ -1427,8 +1426,7 @@ alpha_heuristic_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
 }
 
-static const struct frame_unwind alpha_heuristic_frame_unwind =
+static const struct frame_unwind_legacy alpha_heuristic_frame_unwind (
-{
   "alpha prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1437,7 +1435,7 @@ static const struct frame_unwind alpha_heuristic_frame_unwind =
   alpha_heuristic_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 alpha_heuristic_frame_base_address (const frame_info_ptr &this_frame,

gdb/amd64-obsd-tdep.c

@@ -402,8 +402,7 @@ amd64obsd_trapframe_sniffer (const struct frame_unwind *self,
 		   || (startswith (name, "Xintr"))));
 }
 
-static const struct frame_unwind amd64obsd_trapframe_unwind =
+static const struct frame_unwind_legacy amd64obsd_trapframe_unwind (
-{
   /* FIXME: kettenis/20051219: This really is more like an interrupt
      frame, but SIGTRAMP_FRAME would print <signal handler called>,
      which really is not what we want here.  */
@@ -415,7 +414,7 @@ static const struct frame_unwind amd64obsd_trapframe_unwind =
   amd64obsd_trapframe_prev_register,
   NULL,
   amd64obsd_trapframe_sniffer
-};
+);
 
 
 static void

gdb/amd64-tdep.c

@@ -2666,8 +2666,7 @@ amd64_frame_prev_register (const frame_info_ptr &this_frame, void **this_cache,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind amd64_frame_unwind =
+static const struct frame_unwind_legacy amd64_frame_unwind (
-{
   "amd64 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2676,7 +2675,7 @@ static const struct frame_unwind amd64_frame_unwind =
   amd64_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Generate a bytecode expression to get the value of the saved PC.  */
 
@@ -2813,8 +2812,7 @@ amd64_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind amd64_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy amd64_sigtramp_frame_unwind (
-{
   "amd64 sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2823,7 +2821,7 @@ static const struct frame_unwind amd64_sigtramp_frame_unwind =
   amd64_sigtramp_frame_prev_register,
   NULL,
   amd64_sigtramp_frame_sniffer
-};
+);
 
 
 static CORE_ADDR
@@ -3006,8 +3004,7 @@ amd64_epilogue_frame_this_id (const frame_info_ptr &this_frame,
     (*this_id) = frame_id_build (cache->base + 16, cache->pc);
 }
 
-static const struct frame_unwind amd64_epilogue_override_frame_unwind =
+static const struct frame_unwind_legacy amd64_epilogue_override_frame_unwind (
-{
   "amd64 epilogue override",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3016,10 +3013,9 @@ static const struct frame_unwind amd64_epilogue_override_frame_unwind =
   amd64_frame_prev_register,
   NULL,
   amd64_epilogue_override_frame_sniffer
-};
+);
 
-static const struct frame_unwind amd64_epilogue_frame_unwind =
+static const struct frame_unwind_legacy amd64_epilogue_frame_unwind (
-{
   "amd64 epilogue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3028,7 +3024,7 @@ static const struct frame_unwind amd64_epilogue_frame_unwind =
   amd64_frame_prev_register,
   NULL, 
   amd64_epilogue_frame_sniffer
-};
+);
 
 static struct frame_id
 amd64_dummy_id (struct gdbarch *gdbarch, const frame_info_ptr &this_frame)

gdb/amd64-windows-tdep.c

@@ -1184,8 +1184,7 @@ amd64_windows_frame_this_id (const frame_info_ptr &this_frame, void **this_cache
 
 /* Windows x64 SEH unwinder.  */
 
-static const struct frame_unwind amd64_windows_frame_unwind =
+static const struct frame_unwind_legacy amd64_windows_frame_unwind (
-{
   "amd64 windows",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1194,7 +1193,7 @@ static const struct frame_unwind amd64_windows_frame_unwind =
   &amd64_windows_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Implement the "skip_prologue" gdbarch method.  */
 

gdb/amdgpu-tdep.c

@@ -889,7 +889,7 @@ amdgpu_frame_prev_register (const frame_info_ptr &this_frame, void **this_cache,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const frame_unwind amdgpu_frame_unwind = {
+static const frame_unwind_legacy amdgpu_frame_unwind (
   "amdgpu",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -899,8 +899,8 @@ static const frame_unwind amdgpu_frame_unwind = {
   nullptr,
   default_frame_sniffer,
   nullptr,
-  nullptr,
+  nullptr
-};
+);
 
 static int
 print_insn_amdgpu (bfd_vma memaddr, struct disassemble_info *info)

gdb/arc-tdep.c

@@ -1910,7 +1910,7 @@ arc_sigtramp_frame_sniffer (const struct frame_unwind *self,
    the fallback unwinder, we use the default frame sniffer, which always
    accepts the frame.  */
 
-static const struct frame_unwind arc_frame_unwind = {
+static const struct frame_unwind_legacy arc_frame_unwind (
   "arc prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1921,13 +1921,13 @@ static const struct frame_unwind arc_frame_unwind = {
   default_frame_sniffer,
   NULL,
   NULL
-};
+);
 
 /* Structure defining the ARC signal frame unwind functions.  Custom
    sniffer is used, because this frame must be accepted only in the right
    context.  */
 
-static const struct frame_unwind arc_sigtramp_frame_unwind = {
+static const struct frame_unwind_legacy arc_sigtramp_frame_unwind (
   "arc sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1938,7 +1938,7 @@ static const struct frame_unwind arc_sigtramp_frame_unwind = {
   arc_sigtramp_frame_sniffer,
   NULL,
   NULL
-};
+);
 
 
 static const struct frame_base arc_normal_base = {

gdb/arm-tdep.c

@@ -2466,7 +2466,7 @@ arm_prologue_prev_register (const frame_info_ptr &this_frame,
 				       prev_regnum);
 }
 
-static frame_unwind arm_prologue_unwind = {
+static const frame_unwind_legacy arm_prologue_unwind (
   "arm prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2475,7 +2475,7 @@ static frame_unwind arm_prologue_unwind = {
   arm_prologue_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Maintain a list of ARM exception table entries per objfile, similar to the
    list of mapping symbols.  We only cache entries for standard ARM-defined
@@ -3186,7 +3186,7 @@ arm_exidx_unwind_sniffer (const struct frame_unwind *self,
   return 1;
 }
 
-struct frame_unwind arm_exidx_unwind = {
+struct frame_unwind_legacy arm_exidx_unwind (
   "arm exidx",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3195,7 +3195,7 @@ struct frame_unwind arm_exidx_unwind = {
   arm_prologue_prev_register,
   NULL,
   arm_exidx_unwind_sniffer
-};
+);
 
 static struct arm_prologue_cache *
 arm_make_epilogue_frame_cache (const frame_info_ptr &this_frame)
@@ -3296,8 +3296,7 @@ arm_epilogue_frame_sniffer (const struct frame_unwind *self,
 
 /* Frame unwinder from epilogue.  */
 
-static const struct frame_unwind arm_epilogue_frame_unwind =
+static const struct frame_unwind_legacy arm_epilogue_frame_unwind (
-{
   "arm epilogue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3305,8 +3304,8 @@ static const struct frame_unwind arm_epilogue_frame_unwind =
   arm_epilogue_frame_this_id,
   arm_epilogue_frame_prev_register,
   NULL,
-  arm_epilogue_frame_sniffer,
+  arm_epilogue_frame_sniffer
-};
+);
 
 /* Recognize GCC's trampoline for thumb call-indirect.  If we are in a
    trampoline, return the target PC.  Otherwise return 0.
@@ -3427,7 +3426,7 @@ arm_stub_unwind_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-struct frame_unwind arm_stub_unwind = {
+struct frame_unwind_legacy arm_stub_unwind (
   "arm stub",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3436,7 +3435,7 @@ struct frame_unwind arm_stub_unwind = {
   arm_prologue_prev_register,
   NULL,
   arm_stub_unwind_sniffer
-};
+);
 
 /* Put here the code to store, into CACHE->saved_regs, the addresses
    of the saved registers of frame described by THIS_FRAME.  CACHE is
@@ -3953,8 +3952,7 @@ arm_m_exception_unwind_sniffer (const struct frame_unwind *self,
 /* Frame unwinder for M-profile exceptions (EXC_RETURN on stack),
    lockup and secure/nonsecure interstate function calls (FNC_RETURN).  */
 
-struct frame_unwind arm_m_exception_unwind =
+struct frame_unwind_legacy arm_m_exception_unwind (
-{
   "arm m exception lockup sec_fnc",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3963,7 +3961,7 @@ struct frame_unwind arm_m_exception_unwind =
   arm_m_exception_prev_register,
   NULL,
   arm_m_exception_unwind_sniffer
-};
+);
 
 static CORE_ADDR
 arm_normal_frame_base (const frame_info_ptr &this_frame, void **this_cache)

gdb/avr-tdep.c

@@ -1155,7 +1155,7 @@ avr_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
 }
 
-static const struct frame_unwind avr_frame_unwind = {
+static const struct frame_unwind_legacy avr_frame_unwind (
   "avr prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1164,7 +1164,7 @@ static const struct frame_unwind avr_frame_unwind = {
   avr_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 avr_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/bfin-tdep.c

@@ -372,8 +372,7 @@ bfin_frame_prev_register (const frame_info_ptr &this_frame,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind bfin_frame_unwind =
+static const struct frame_unwind_legacy bfin_frame_unwind (
-{
   "bfin prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -382,7 +381,7 @@ static const struct frame_unwind bfin_frame_unwind =
   bfin_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Check for "[--SP] = <reg>;" insns.  These are appear in function
    prologues to save misc registers onto the stack.  */

gdb/bpf-tdep.c

@@ -181,8 +181,7 @@ bpf_frame_prev_register (const frame_info_ptr &this_frame,
 
 /* Frame unwinder machinery for BPF.  */
 
-static const struct frame_unwind bpf_frame_unwind =
+static const struct frame_unwind_legacy bpf_frame_unwind (
-{
   "bpf prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -191,7 +190,7 @@ static const struct frame_unwind bpf_frame_unwind =
   bpf_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 
 /* Breakpoints.  */

gdb/cris-tdep.c

@@ -435,8 +435,7 @@ cris_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind cris_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy cris_sigtramp_frame_unwind (
-{
   "cris sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -445,7 +444,7 @@ static const struct frame_unwind cris_sigtramp_frame_unwind =
   cris_sigtramp_frame_prev_register,
   NULL,
   cris_sigtramp_frame_sniffer
-};
+);
 
 static int
 crisv32_single_step_through_delay (struct gdbarch *gdbarch,
@@ -901,8 +900,7 @@ cris_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   return sp;
 }
 
-static const struct frame_unwind cris_frame_unwind = 
+static const struct frame_unwind_legacy cris_frame_unwind (
-{
   "cris prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -911,7 +909,7 @@ static const struct frame_unwind cris_frame_unwind =
   cris_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 cris_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/csky-tdep.c

@@ -2159,7 +2159,7 @@ csky_frame_prev_register (const frame_info_ptr &this_frame,
 /* Data structures for the normal prologue-analysis-based
    unwinder.  */
 
-static const struct frame_unwind csky_unwind_cache = {
+static const struct frame_unwind_legacy csky_unwind_cache (
   "cski prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2170,7 +2170,7 @@ static const struct frame_unwind csky_unwind_cache = {
   default_frame_sniffer,
   NULL,
   NULL
-};
+);
 
 static CORE_ADDR
 csky_check_long_branch (const frame_info_ptr &frame, CORE_ADDR pc)
@@ -2294,7 +2294,7 @@ csky_stub_prev_register (const frame_info_ptr &this_frame,
 				       prev_regnum);
 }
 
-static frame_unwind csky_stub_unwind = {
+static const frame_unwind_legacy csky_stub_unwind (
   "csky stub",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2303,7 +2303,7 @@ static frame_unwind csky_stub_unwind = {
   csky_stub_prev_register,
   NULL,
   csky_stub_unwind_sniffer
-};
+);
 
 /* Implement the this_base, this_locals, and this_args hooks
    for the normal unwinder.  */

gdb/dummy-frame.c

@@ -375,8 +375,7 @@ dummy_frame_this_id (const frame_info_ptr &this_frame,
   (*this_id) = cache->this_id;
 }
 
-const struct frame_unwind dummy_frame_unwind =
+const struct frame_unwind_legacy dummy_frame_unwind (
-{
   "dummy",
   DUMMY_FRAME,
   FRAME_UNWIND_GDB,
@@ -384,8 +383,8 @@ const struct frame_unwind dummy_frame_unwind =
   dummy_frame_this_id,
   dummy_frame_prev_register,
   NULL,
-  dummy_frame_sniffer,
+  dummy_frame_sniffer
-};
+);
 
 /* See dummy-frame.h.  */
 

gdb/dummy-frame.h

@@ -54,7 +54,7 @@ extern void dummy_frame_discard (frame_id dummy_id, thread_info *thread);
 /* If the PC falls in a dummy frame, return a dummy frame
    unwinder.  */
 
-extern const struct frame_unwind dummy_frame_unwind;
+extern const struct frame_unwind_legacy dummy_frame_unwind;
 
 /* Destructor for dummy_frame.  DATA is supplied by registrant.
    REGISTERS_VALID is 1 for dummy_frame_pop, 0 for dummy_frame_discard.  */

gdb/dwarf2/frame-tailcall.c

@@ -468,8 +468,7 @@ tailcall_frame_prev_arch (const frame_info_ptr &this_frame,
 /* Virtual tail call frame unwinder if dwarf2_tailcall_sniffer_first finds
    a chain to create.  */
 
-const struct frame_unwind dwarf2_tailcall_frame_unwind =
+const struct frame_unwind_legacy dwarf2_tailcall_frame_unwind (
-{
   "dwarf2 tailcall",
   TAILCALL_FRAME,
   FRAME_UNWIND_DEBUGINFO,
@@ -480,7 +479,7 @@ const struct frame_unwind dwarf2_tailcall_frame_unwind =
   tailcall_frame_sniffer,
   tailcall_frame_dealloc_cache,
   tailcall_frame_prev_arch
-};
+);
 
 void _initialize_tailcall_frame ();
 void

gdb/dwarf2/frame-tailcall.h

@@ -34,6 +34,6 @@ extern struct value *
   dwarf2_tailcall_prev_register_first (const frame_info_ptr &this_frame,
 				       void **tailcall_cachep, int regnum);
 
-extern const struct frame_unwind dwarf2_tailcall_frame_unwind;
+extern const struct frame_unwind_legacy dwarf2_tailcall_frame_unwind;
 
 #endif /* GDB_DWARF2_FRAME_TAILCALL_H */

gdb/dwarf2/frame.c

@@ -1329,16 +1329,15 @@ dwarf2_frame_sniffer (const struct frame_unwind *self,
   if (fde->cie->signal_frame
       || dwarf2_frame_signal_frame_p (get_frame_arch (this_frame),
 				      this_frame))
-    return self->type == SIGTRAMP_FRAME;
+    return self->type () == SIGTRAMP_FRAME;
 
-  if (self->type != NORMAL_FRAME)
+  if (self->type () != NORMAL_FRAME)
     return 0;
 
   return 1;
 }
 
-static const struct frame_unwind dwarf2_frame_unwind =
+static const struct frame_unwind_legacy dwarf2_frame_unwind (
-{
   "dwarf2",
   NORMAL_FRAME,
   FRAME_UNWIND_DEBUGINFO,
@@ -1348,10 +1347,9 @@ static const struct frame_unwind dwarf2_frame_unwind =
   NULL,
   dwarf2_frame_sniffer,
   dwarf2_frame_dealloc_cache
-};
+);
 
-static const struct frame_unwind dwarf2_signal_frame_unwind =
+static const struct frame_unwind_legacy dwarf2_signal_frame_unwind (
-{
   "dwarf2 signal",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_DEBUGINFO,
@@ -1363,7 +1361,7 @@ static const struct frame_unwind dwarf2_signal_frame_unwind =
 
   /* TAILCALL_CACHE can never be in such frame to need dealloc_cache.  */
   NULL
-};
+);
 
 /* Append the DWARF-2 frame unwinders to GDBARCH's list.  */
 

gdb/frame-unwind.c

@@ -122,8 +122,8 @@ frame_unwind_try_unwinder (const frame_info_ptr &this_frame, void **this_cache,
 
   try
     {
-      frame_debug_printf ("trying unwinder \"%s\"", unwinder->name);
+      frame_debug_printf ("trying unwinder \"%s\"", unwinder->name ());
-      res = unwinder->sniffer (unwinder, this_frame, this_cache);
+      res = unwinder->sniff (this_frame, this_cache);
     }
   catch (const gdb_exception &ex)
     {
@@ -340,6 +340,64 @@ frame_unwind_got_address (const frame_info_ptr &frame, int regnum,
   return reg_val;
 }
 
+/* See frame-unwind.h.  */
+
+enum unwind_stop_reason
+frame_unwind_legacy::stop_reason (const frame_info_ptr &this_frame,
+				  void **this_prologue_cache) const
+{
+  return m_stop_reason (this_frame, this_prologue_cache);
+}
+
+/* See frame-unwind.h.  */
+
+void
+frame_unwind_legacy::this_id (const frame_info_ptr &this_frame,
+			      void **this_prologue_cache,
+			      struct frame_id *id) const
+{
+  return m_this_id (this_frame, this_prologue_cache, id);
+}
+
+/* See frame-unwind.h.  */
+
+struct value *
+frame_unwind_legacy::prev_register (const frame_info_ptr &this_frame,
+				    void **this_prologue_cache,
+				    int regnum) const
+{
+  return m_prev_register (this_frame, this_prologue_cache, regnum);
+}
+
+/* See frame-unwind.h.  */
+
+int
+frame_unwind_legacy::sniff (const frame_info_ptr &this_frame,
+			    void **this_prologue_cache) const
+{
+  return m_sniffer (this, this_frame, this_prologue_cache);
+}
+
+/* See frame-unwind.h.  */
+
+void
+frame_unwind_legacy::dealloc_cache (frame_info *self, void *this_cache) const
+{
+  if (m_dealloc_cache != nullptr)
+    m_dealloc_cache (self, this_cache);
+}
+
+/* See frame-unwind.h.  */
+
+struct gdbarch *
+frame_unwind_legacy::prev_arch (const frame_info_ptr &this_frame,
+				void **this_prologue_cache) const
+{
+  if (m_prev_arch == nullptr)
+    return frame_unwind::prev_arch (this_frame, this_prologue_cache);
+  return m_prev_arch (this_frame, this_prologue_cache);
+}
+
 /* Implement "maintenance info frame-unwinders" command.  */
 
 static void
@@ -358,10 +416,10 @@ maintenance_info_frame_unwinders (const char *args, int from_tty)
   for (const auto &unwinder : table)
     {
       ui_out_emit_list tuple_emitter (uiout, nullptr);
-      uiout->field_string ("name", unwinder->name);
+      uiout->field_string ("name", unwinder->name ());
-      uiout->field_string ("type", frame_type_str (unwinder->type));
+      uiout->field_string ("type", frame_type_str (unwinder->type ()));
       uiout->field_string ("class", frame_unwinder_class_str (
-					unwinder->unwinder_class));
+					unwinder->unwinder_class ()));
       uiout->text ("\n");
     }
 }

gdb/frame-unwind.h

@@ -171,25 +171,147 @@ enum frame_unwind_class
   UNWIND_CLASS_NUMBER,
 };
 
-struct frame_unwind
+class frame_unwind
 {
-  const char *name;
+public:
+  frame_unwind (const char *name, frame_type type, frame_unwind_class uclass,
+		const frame_data *data)
+    : m_name (name), m_type (type), m_unwinder_class (uclass),
+      m_unwind_data (data)
+  { }
+
+  const char *name () const
+  { return m_name; }
+
+  frame_type type () const
+  { return m_type; }
+
+  frame_unwind_class unwinder_class () const
+  { return m_unwinder_class; }
+
+  const frame_data *unwind_data () const
+  { return m_unwind_data; }
+
+  /* Default stop_reason implementation.  It reports NO_REASON, unless the
+     frame is the outermost.  */
+
+  virtual unwind_stop_reason stop_reason (const frame_info_ptr &this_frame,
+					  void **this_prologue_cache) const
+  {
+    return default_frame_unwind_stop_reason (this_frame, this_prologue_cache);
+  }
+
+  /* Default frame sniffer.  Will always return that the unwinder
+     is able to unwind the frame.  */
+
+  virtual int sniff (const frame_info_ptr &this_frame,
+		     void **this_prologue_cache) const
+  { return 1; }
+
+  /* Calculate the ID of the given frame using this unwinder.  */
+
+  virtual void this_id (const frame_info_ptr &this_frame,
+			void **this_prologue_cache,
+			struct frame_id *id) const = 0;
+
+  /* Get the value of a register in a previous frame.  */
+
+  virtual struct value *prev_register (const frame_info_ptr &this_frame,
+				       void **this_prologue_cache,
+				       int regnum) const = 0;
+
+  /* Properly deallocate the cache.  */
+
+  virtual void dealloc_cache (frame_info *self, void *this_cache) const
+  { }
+
+  /* Get the previous architecture.  */
+
+  virtual gdbarch *prev_arch (const frame_info_ptr &this_frame,
+			      void **this_prologue_cache) const
+  { return get_frame_arch (this_frame); }
+
+private:
+
+  /* Name of the unwinder.  Used to uniquely identify unwinders.  */
+  const char *m_name;
+
   /* The frame's type.  Should this instead be a collection of
      predicates that test the frame for various attributes?  */
-  enum frame_type type;
+  frame_type m_type;
+
   /* What kind of unwinder is this.  It generally follows from where
      the unwinder was added or where it looks for information to do the
      unwinding.  */
-  enum frame_unwind_class unwinder_class;
+  frame_unwind_class m_unwinder_class;
-  /* Should an attribute indicating the frame's address-in-block go
+
-     here?  */
+  /* Additional data used by the trampoline and python frame unwinders.  */
-  frame_unwind_stop_reason_ftype *stop_reason;
+  const frame_data *m_unwind_data;
-  frame_this_id_ftype *this_id;
+};
-  frame_prev_register_ftype *prev_register;
+
-  const struct frame_data *unwind_data;
+/* This is a legacy version of the frame unwinder.  The original struct
-  frame_sniffer_ftype *sniffer;
+   used function pointers for callbacks, this updated version has a
-  frame_dealloc_cache_ftype *dealloc_cache;
+   method that just passes the parameters along to the callback
-  frame_prev_arch_ftype *prev_arch;
+   pointer.
+   Do not use this class for new unwinders.  Instead, see other classes
+   that inherit from frame_unwind, such as the python unwinder.  */
+struct frame_unwind_legacy : public frame_unwind
+{
+  frame_unwind_legacy (const char *name, frame_type type,
+		       frame_unwind_class uclass,
+		       frame_unwind_stop_reason_ftype *stop_reason_func,
+		       frame_this_id_ftype *this_id_func,
+		       frame_prev_register_ftype *prev_register_func,
+		       const struct frame_data *data,
+		       frame_sniffer_ftype *sniffer_func,
+		       frame_dealloc_cache_ftype *dealloc_cache_func = nullptr,
+		       frame_prev_arch_ftype *prev_arch_func = nullptr)
+  : frame_unwind (name, type, uclass, data), m_stop_reason (stop_reason_func),
+    m_this_id (this_id_func), m_prev_register (prev_register_func),
+    m_sniffer (sniffer_func), m_dealloc_cache (dealloc_cache_func),
+    m_prev_arch (prev_arch_func)
+  { }
+
+  /* This method just passes the parameters to the callback pointer.  */
+
+  enum unwind_stop_reason stop_reason (const frame_info_ptr &this_frame,
+				       void **this_prologue_cache) const override;
+
+  /* This method just passes the parameters to the callback pointer.  */
+
+  void this_id (const frame_info_ptr &this_frame, void **this_prologue_cache,
+		struct frame_id *id) const override;
+
+  /* This method just passes the parameters to the callback pointer.  */
+
+  struct value *prev_register (const frame_info_ptr &this_frame,
+			       void **this_prologue_cache,
+			       int regnum) const override;
+
+  /* This method just passes the parameters to the callback pointer.  */
+
+  int sniff (const frame_info_ptr &this_frame,
+	     void **this_prologue_cache) const override;
+
+  /* This method just passes the parameters to the callback pointer.
+     It is safe to call this method if no callback is installed, it
+     just turns into a noop.  */
+
+  void dealloc_cache (frame_info *self, void *this_cache) const override;
+
+  /* This method just passes the parameters to the callback pointer.  */
+
+  struct gdbarch *prev_arch (const frame_info_ptr &this_frame,
+			     void **this_prologue_cache) const override;
+
+private:
+
+  frame_unwind_stop_reason_ftype *m_stop_reason;
+  frame_this_id_ftype *m_this_id;
+  frame_prev_register_ftype *m_prev_register;
+  frame_sniffer_ftype *m_sniffer;
+  frame_dealloc_cache_ftype *m_dealloc_cache;
+  frame_prev_arch_ftype *m_prev_arch;
 };
 
 /* Register a frame unwinder, _prepending_ it to the front of the

gdb/frame.c

@@ -269,12 +269,10 @@ frame_addr_hash_eq (const void *a, const void *b)
 static void
 frame_info_del (frame_info *frame)
 {
-  if (frame->prologue_cache != nullptr
+  if (frame->prologue_cache != nullptr)
-      && frame->unwind->dealloc_cache != nullptr)
     frame->unwind->dealloc_cache (frame, frame->prologue_cache);
 
-  if (frame->base_cache != nullptr
+  if (frame->base_cache != nullptr)
-      && frame->base->unwind->dealloc_cache != nullptr)
     frame->base->unwind->dealloc_cache (frame, frame->base_cache);
 }
 
@@ -487,12 +485,12 @@ frame_info::to_string () const
   res += string_printf ("{level=%d,", fi->level);
 
   if (fi->unwind != NULL)
-    res += string_printf ("type=%s,", frame_type_str (fi->unwind->type));
+    res += string_printf ("type=%s,", frame_type_str (fi->unwind->type ()));
   else
     res += "type=<unknown>,";
 
   if (fi->unwind != NULL)
-    res += string_printf ("unwinder=\"%s\",", fi->unwind->name);
+    res += string_printf ("unwinder=\"%s\",", fi->unwind->name ());
   else
     res += "unwinder=<unknown>,";
 
@@ -2366,7 +2364,7 @@ get_prev_frame_always_1 (const frame_info_ptr &this_frame)
      This check is valid only if this frame and the next frame are NORMAL.
      See the comment at frame_id_inner for details.  */
   if (get_frame_type (this_frame) == NORMAL_FRAME
-      && this_frame->next->unwind->type == NORMAL_FRAME
+      && this_frame->next->unwind->type () == NORMAL_FRAME
       && frame_id_inner (get_frame_arch (frame_info_ptr (this_frame->next)),
 			 get_frame_id (this_frame),
 			 get_frame_id (frame_info_ptr (this_frame->next))))
@@ -2994,7 +2992,7 @@ get_frame_type (const frame_info_ptr &frame)
     /* Initialize the frame's unwinder because that's what
        provides the frame's type.  */
     frame_unwind_find_by_frame (frame, &frame->prologue_cache);
-  return frame->unwind->type;
+  return frame->unwind->type ();
 }
 
 struct program_space *
@@ -3075,11 +3073,8 @@ frame_unwind_arch (const frame_info_ptr &next_frame)
       if (next_frame->unwind == NULL)
 	frame_unwind_find_by_frame (next_frame, &next_frame->prologue_cache);
 
-      if (next_frame->unwind->prev_arch != NULL)
       arch = next_frame->unwind->prev_arch (next_frame,
 					    &next_frame->prologue_cache);
-      else
-	arch = get_frame_arch (next_frame);
 
       next_frame->prev_arch.arch = arch;
       next_frame->prev_arch.p = true;

gdb/frv-linux-tdep.c

@@ -332,8 +332,7 @@ frv_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind frv_linux_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy frv_linux_sigtramp_frame_unwind (
-{
   "frv linux sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -342,7 +341,7 @@ static const struct frame_unwind frv_linux_sigtramp_frame_unwind =
   frv_linux_sigtramp_frame_prev_register,
   NULL,
   frv_linux_sigtramp_frame_sniffer
-};
+);
 
 /* The FRV kernel defines ELF_NGREG as 46.  We add 2 in order to include
    the loadmap addresses in the register set.  (See below for more info.)  */

gdb/frv-tdep.c

@@ -1404,7 +1404,7 @@ frv_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
 }
 
-static const struct frame_unwind frv_frame_unwind = {
+static const struct frame_unwind_legacy frv_frame_unwind (
   "frv prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1413,7 +1413,7 @@ static const struct frame_unwind frv_frame_unwind = {
   frv_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 frv_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/ft32-tdep.c

@@ -525,8 +525,7 @@ ft32_frame_prev_register (const frame_info_ptr &this_frame,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind ft32_frame_unwind =
+static const struct frame_unwind_legacy ft32_frame_unwind (
-{
   "ft32 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -535,7 +534,7 @@ static const struct frame_unwind ft32_frame_unwind =
   ft32_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Return the base address of this_frame.  */
 

gdb/h8300-tdep.c

@@ -500,7 +500,7 @@ h8300_frame_prev_register (const frame_info_ptr &this_frame, void **this_cache,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind h8300_frame_unwind = {
+static const struct frame_unwind_legacy h8300_frame_unwind (
   "h8300 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -509,7 +509,7 @@ static const struct frame_unwind h8300_frame_unwind = {
   h8300_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 h8300_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/hppa-linux-tdep.c

@@ -308,7 +308,7 @@ hppa_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = {
+static const struct frame_unwind_legacy hppa_linux_sigtramp_frame_unwind (
   "hppa linux sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -317,7 +317,7 @@ static const struct frame_unwind hppa_linux_sigtramp_frame_unwind = {
   hppa_linux_sigtramp_frame_prev_register,
   NULL,
   hppa_linux_sigtramp_frame_sniffer
-};
+);
 
 /* Attempt to find (and return) the global pointer for the given
    function.

gdb/hppa-tdep.c

@@ -2282,8 +2282,7 @@ hppa_frame_unwind_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind hppa_frame_unwind =
+static const struct frame_unwind_legacy hppa_frame_unwind (
-{
   "hppa unwind table",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2292,7 +2291,7 @@ static const struct frame_unwind hppa_frame_unwind =
   hppa_frame_prev_register,
   NULL,
   hppa_frame_unwind_sniffer
-};
+);
 
 /* This is a generic fallback frame unwinder that kicks in if we fail all
    the other ones.  Normally we would expect the stub and regular unwinder
@@ -2396,8 +2395,7 @@ hppa_fallback_frame_prev_register (const frame_info_ptr &this_frame,
 					  info->saved_regs, regnum);
 }
 
-static const struct frame_unwind hppa_fallback_frame_unwind =
+static const struct frame_unwind_legacy hppa_fallback_frame_unwind (
-{
   "hppa prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2406,7 +2404,7 @@ static const struct frame_unwind hppa_fallback_frame_unwind =
   hppa_fallback_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Stub frames, used for all kinds of call stubs.  */
 struct hppa_stub_unwind_cache
@@ -2479,7 +2477,7 @@ hppa_stub_unwind_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind hppa_stub_frame_unwind = {
+static const struct frame_unwind_legacy hppa_stub_frame_unwind (
   "hppa stub",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2488,7 +2486,7 @@ static const struct frame_unwind hppa_stub_frame_unwind = {
   hppa_stub_frame_prev_register,
   NULL,
   hppa_stub_unwind_sniffer
-};
+);
 
 CORE_ADDR
 hppa_unwind_pc (struct gdbarch *gdbarch, const frame_info_ptr &next_frame)

gdb/i386-obsd-tdep.c

@@ -390,7 +390,7 @@ i386obsd_trapframe_sniffer (const struct frame_unwind *self,
 		   || startswith (name, "Xsoft")));
 }
 
-static const struct frame_unwind i386obsd_trapframe_unwind = {
+static const struct frame_unwind_legacy i386obsd_trapframe_unwind (
   "i386 openbsd trap",
   /* FIXME: kettenis/20051219: This really is more like an interrupt
      frame, but SIGTRAMP_FRAME would print <signal handler called>,
@@ -402,7 +402,7 @@ static const struct frame_unwind i386obsd_trapframe_unwind = {
   i386obsd_trapframe_prev_register,
   NULL,
   i386obsd_trapframe_sniffer
-};
+);
 
 
 static void 

gdb/i386-tdep.c

@@ -2139,8 +2139,7 @@ i386_frame_prev_register (const frame_info_ptr &this_frame, void **this_cache,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind i386_frame_unwind =
+static const struct frame_unwind_legacy i386_frame_unwind (
-{
   "i386 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2149,7 +2148,7 @@ static const struct frame_unwind i386_frame_unwind =
   i386_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Normal frames, but in a function epilogue.  */
 
@@ -2295,8 +2294,7 @@ i386_epilogue_frame_prev_register (const frame_info_ptr &this_frame,
   return i386_frame_prev_register (this_frame, this_cache, regnum);
 }
 
-static const struct frame_unwind i386_epilogue_override_frame_unwind =
+static const struct frame_unwind_legacy i386_epilogue_override_frame_unwind (
-{
   "i386 epilogue override",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2305,10 +2303,9 @@ static const struct frame_unwind i386_epilogue_override_frame_unwind =
   i386_epilogue_frame_prev_register,
   NULL,
   i386_epilogue_override_frame_sniffer
-};
+);
 
-static const struct frame_unwind i386_epilogue_frame_unwind =
+static const struct frame_unwind_legacy i386_epilogue_frame_unwind (
-{
   "i386 epilogue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2317,7 +2314,7 @@ static const struct frame_unwind i386_epilogue_frame_unwind =
   i386_epilogue_frame_prev_register,
   NULL,
   i386_epilogue_frame_sniffer
-};
+);
 
 
 /* Stack-based trampolines.  */
@@ -2390,8 +2387,7 @@ i386_stack_tramp_frame_sniffer (const struct frame_unwind *self,
     return 0;
 }
 
-static const struct frame_unwind i386_stack_tramp_frame_unwind =
+static const struct frame_unwind_legacy i386_stack_tramp_frame_unwind (
-{
   "i386 stack tramp",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2400,7 +2396,7 @@ static const struct frame_unwind i386_stack_tramp_frame_unwind =
   i386_epilogue_frame_prev_register,
   NULL,
   i386_stack_tramp_frame_sniffer
-};
+);
 
 /* Generate a bytecode expression to get the value of the saved PC.  */
 
@@ -2540,8 +2536,7 @@ i386_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind i386_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy i386_sigtramp_frame_unwind (
-{
   "i386 sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2550,7 +2545,7 @@ static const struct frame_unwind i386_sigtramp_frame_unwind =
   i386_sigtramp_frame_prev_register,
   NULL,
   i386_sigtramp_frame_sniffer
-};
+);
 
 
 static CORE_ADDR

gdb/ia64-tdep.c

@@ -2162,8 +2162,7 @@ ia64_frame_prev_register (const frame_info_ptr &this_frame, void **this_cache,
     }
 }
  
-static const struct frame_unwind ia64_frame_unwind =
+static const struct frame_unwind_legacy ia64_frame_unwind (
-{
   "ia64 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2172,7 +2171,7 @@ static const struct frame_unwind ia64_frame_unwind =
   &ia64_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Signal trampolines.  */
 
@@ -2352,8 +2351,7 @@ ia64_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind ia64_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy ia64_sigtramp_frame_unwind (
-{
   "ia64 sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2362,7 +2360,7 @@ static const struct frame_unwind ia64_sigtramp_frame_unwind =
   ia64_sigtramp_frame_prev_register,
   NULL,
   ia64_sigtramp_frame_sniffer
-};
+);
 
 
 
@@ -3013,8 +3011,7 @@ ia64_libunwind_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind ia64_libunwind_frame_unwind =
+static const struct frame_unwind_legacy ia64_libunwind_frame_unwind (
-{
   "ia64 libunwind",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3024,7 +3021,7 @@ static const struct frame_unwind ia64_libunwind_frame_unwind =
   NULL,
   ia64_libunwind_frame_sniffer,
   libunwind_frame_dealloc_cache
-};
+);
 
 static void
 ia64_libunwind_sigtramp_frame_this_id (const frame_info_ptr &this_frame,
@@ -3103,8 +3100,7 @@ ia64_libunwind_sigtramp_frame_sniffer (const struct frame_unwind *self,
     return ia64_sigtramp_frame_sniffer (self, this_frame, this_cache);
 }
 
-static const struct frame_unwind ia64_libunwind_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy ia64_libunwind_sigtramp_frame_unwind (
-{
   "ia64 libunwind sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3113,7 +3109,7 @@ static const struct frame_unwind ia64_libunwind_sigtramp_frame_unwind =
   ia64_libunwind_sigtramp_frame_prev_register,
   NULL,
   ia64_libunwind_sigtramp_frame_sniffer
-};
+);
 
 /* Set of libunwind callback acccessor functions.  */
 unw_accessors_t ia64_unw_accessors =

gdb/inline-frame.c

@@ -270,7 +270,7 @@ inline_frame_sniffer (const struct frame_unwind *self,
   return 1;
 }
 
-const struct frame_unwind inline_frame_unwind = {
+const struct frame_unwind_legacy inline_frame_unwind (
   "inline",
   INLINE_FRAME,
   FRAME_UNWIND_GDB,
@@ -279,7 +279,7 @@ const struct frame_unwind inline_frame_unwind = {
   inline_frame_prev_register,
   NULL,
   inline_frame_sniffer
-};
+);
 
 /* Return non-zero if BLOCK, an inlined function block containing PC,
    has a group of contiguous instructions starting at PC (but not

gdb/inline-frame.h

@@ -27,7 +27,7 @@ struct process_stratum_target;
 
 /* The inline frame unwinder.  */
 
-extern const struct frame_unwind inline_frame_unwind;
+extern const struct frame_unwind_legacy inline_frame_unwind;
 
 /* Skip all inlined functions whose call sites are at the current PC.
 

gdb/iq2000-tdep.c

@@ -424,7 +424,7 @@ iq2000_frame_this_id (const frame_info_ptr &this_frame, void **this_cache,
   *this_id = frame_id_build (cache->saved_sp, cache->pc);
 }
 
-static const struct frame_unwind iq2000_frame_unwind = {
+static const struct frame_unwind_legacy iq2000_frame_unwind (
   "iq2000 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -433,7 +433,7 @@ static const struct frame_unwind iq2000_frame_unwind = {
   iq2000_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 iq2000_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/jit.c

@@ -1112,8 +1112,7 @@ jit_frame_prev_register (const frame_info_ptr &this_frame, void **cache, int reg
 /* Relay everything back to the unwinder registered by the JIT debug
    info reader.*/
 
-static const struct frame_unwind jit_frame_unwind =
+static const struct frame_unwind_legacy jit_frame_unwind (
-{
   "jit",
   NORMAL_FRAME,
   FRAME_UNWIND_EXTENSION,
@@ -1123,7 +1122,7 @@ static const struct frame_unwind jit_frame_unwind =
   NULL,
   jit_frame_sniffer,
   jit_dealloc_cache
-};
+);
 
 
 /* This is the information that is stored at jit_gdbarch_data for each

gdb/lm32-tdep.c

@@ -447,7 +447,7 @@ lm32_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
 }
 
-static const struct frame_unwind lm32_frame_unwind = {
+static const struct frame_unwind_legacy lm32_frame_unwind (
   "lm32 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -456,7 +456,7 @@ static const struct frame_unwind lm32_frame_unwind = {
   lm32_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 lm32_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/loongarch-tdep.c

@@ -454,7 +454,7 @@ loongarch_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_register (info, this_frame, regnum);
 }
 
-static const struct frame_unwind loongarch_frame_unwind = {
+static const struct frame_unwind_legacy loongarch_frame_unwind (
   "loongarch prologue",
   /*.type	   =*/NORMAL_FRAME,
   /*.unwinder_class=*/FRAME_UNWIND_ARCH,
@@ -464,8 +464,8 @@ static const struct frame_unwind loongarch_frame_unwind = {
   /*.unwind_data   =*/nullptr,
   /*.sniffer	   =*/default_frame_sniffer,
   /*.dealloc_cache =*/nullptr,
-  /*.prev_arch	   =*/nullptr,
+  /*.prev_arch	   =*/nullptr
-};
+);
 
 /* Write the contents of buffer VAL into the general-purpose argument
    register defined by GAR in REGCACHE.  GAR indicates the available

gdb/m32c-tdep.c

@@ -1955,7 +1955,7 @@ m32c_prev_register (const frame_info_ptr &this_frame,
 }
 
 
-static const struct frame_unwind m32c_unwind = {
+static const struct frame_unwind_legacy m32c_unwind (
   "m32c prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1964,7 +1964,7 @@ static const struct frame_unwind m32c_unwind = {
   m32c_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 
 /* Inferior calls.  */

gdb/m32r-linux-tdep.c

@@ -301,7 +301,7 @@ m32r_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind m32r_linux_sigtramp_frame_unwind = {
+static const struct frame_unwind_legacy m32r_linux_sigtramp_frame_unwind (
   "m32r linux sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -310,7 +310,7 @@ static const struct frame_unwind m32r_linux_sigtramp_frame_unwind = {
   m32r_linux_sigtramp_frame_prev_register,
   NULL,
   m32r_linux_sigtramp_frame_sniffer
-};
+);
 
 /* Mapping between the registers in `struct pt_regs'
    format and GDB's register array layout.  */

gdb/m32r-tdep.c

@@ -831,7 +831,7 @@ m32r_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
 }
 
-static const struct frame_unwind m32r_frame_unwind = {
+static const struct frame_unwind_legacy m32r_frame_unwind (
   "m32r prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -840,7 +840,7 @@ static const struct frame_unwind m32r_frame_unwind = {
   m32r_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 m32r_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/m68hc11-tdep.c

@@ -933,7 +933,7 @@ m68hc11_frame_prev_register (const frame_info_ptr &this_frame,
   return value;
 }
 
-static const struct frame_unwind m68hc11_frame_unwind = {
+static const struct frame_unwind_legacy m68hc11_frame_unwind (
   "m68hc11 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -942,7 +942,7 @@ static const struct frame_unwind m68hc11_frame_unwind = {
   m68hc11_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 m68hc11_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/m68k-linux-tdep.c

@@ -314,8 +314,7 @@ m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return m68k_linux_pc_in_sigtramp (this_frame);
 }
 
-static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy m68k_linux_sigtramp_frame_unwind (
-{
   "m68k linux sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -324,7 +323,7 @@ static const struct frame_unwind m68k_linux_sigtramp_frame_unwind =
   m68k_linux_sigtramp_frame_prev_register,
   NULL,
   m68k_linux_sigtramp_frame_sniffer
-};
+);
 
 /* Register maps for supply/collect regset functions.  */
 

gdb/m68k-tdep.c

@@ -1007,8 +1007,7 @@ m68k_frame_prev_register (const frame_info_ptr &this_frame, void **this_cache,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind m68k_frame_unwind =
+static const struct frame_unwind_legacy m68k_frame_unwind (
-{
   "m68k prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1017,7 +1016,7 @@ static const struct frame_unwind m68k_frame_unwind =
   m68k_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 m68k_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/mep-tdep.c

@@ -2061,7 +2061,7 @@ mep_frame_prev_register (const frame_info_ptr &this_frame,
 }
 
 
-static const struct frame_unwind mep_frame_unwind = {
+static const struct frame_unwind_legacy mep_frame_unwind (
   "mep prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2070,7 +2070,7 @@ static const struct frame_unwind mep_frame_unwind = {
   mep_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 
 /* Return values.  */

gdb/microblaze-tdep.c

@@ -478,8 +478,7 @@ microblaze_frame_prev_register (const frame_info_ptr &this_frame,
 
 }
 
-static const struct frame_unwind microblaze_frame_unwind =
+static const struct frame_unwind_legacy microblaze_frame_unwind (
-{
   "microblaze prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -488,7 +487,7 @@ static const struct frame_unwind microblaze_frame_unwind =
   microblaze_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 microblaze_frame_base_address (const frame_info_ptr &next_frame,

gdb/mips-sde-tdep.c

@@ -160,8 +160,7 @@ mips_sde_frame_sniffer (const struct frame_unwind *self,
 
 /* Data structure for the SDE frame unwinder.  */
 
-static const struct frame_unwind mips_sde_frame_unwind =
+static const struct frame_unwind_legacy mips_sde_frame_unwind (
-{
   "mips sde sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -170,7 +169,7 @@ static const struct frame_unwind mips_sde_frame_unwind =
   mips_sde_frame_prev_register,
   NULL,
   mips_sde_frame_sniffer
-};
+);
 
 /* Implement the this_base, this_locals, and this_args hooks
    for the normal unwinder.  */

gdb/mips-tdep.c

@@ -2928,8 +2928,7 @@ mips_insn16_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind mips_insn16_frame_unwind =
+static const struct frame_unwind_legacy mips_insn16_frame_unwind (
-{
   "mips insn16 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2938,7 +2937,7 @@ static const struct frame_unwind mips_insn16_frame_unwind =
   mips_insn16_frame_prev_register,
   NULL,
   mips_insn16_frame_sniffer
-};
+);
 
 static CORE_ADDR
 mips_insn16_frame_base_address (const frame_info_ptr &this_frame,
@@ -3365,8 +3364,7 @@ mips_micro_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind mips_micro_frame_unwind =
+static const struct frame_unwind_legacy mips_micro_frame_unwind (
-{
   "mips micro prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3375,7 +3373,7 @@ static const struct frame_unwind mips_micro_frame_unwind =
   mips_micro_frame_prev_register,
   NULL,
   mips_micro_frame_sniffer
-};
+);
 
 static CORE_ADDR
 mips_micro_frame_base_address (const frame_info_ptr &this_frame,
@@ -3745,8 +3743,7 @@ mips_insn32_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind mips_insn32_frame_unwind =
+static const struct frame_unwind_legacy mips_insn32_frame_unwind (
-{
   "mips insn32 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3755,7 +3752,7 @@ static const struct frame_unwind mips_insn32_frame_unwind =
   mips_insn32_frame_prev_register,
   NULL,
   mips_insn32_frame_sniffer
-};
+);
 
 static CORE_ADDR
 mips_insn32_frame_base_address (const frame_info_ptr &this_frame,
@@ -3862,8 +3859,7 @@ mips_stub_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind mips_stub_frame_unwind =
+static const struct frame_unwind_legacy mips_stub_frame_unwind (
-{
   "mips stub",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3872,7 +3868,7 @@ static const struct frame_unwind mips_stub_frame_unwind =
   mips_stub_frame_prev_register,
   NULL,
   mips_stub_frame_sniffer
-};
+);
 
 static CORE_ADDR
 mips_stub_frame_base_address (const frame_info_ptr &this_frame,

gdb/mn10300-tdep.c

@@ -1127,7 +1127,7 @@ mn10300_frame_prev_register (const frame_info_ptr &this_frame,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind mn10300_frame_unwind = {
+static const struct frame_unwind_legacy mn10300_frame_unwind (
   "mn10300 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1136,7 +1136,7 @@ static const struct frame_unwind mn10300_frame_unwind = {
   mn10300_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static void
 mn10300_frame_unwind_init (struct gdbarch *gdbarch)

gdb/moxie-tdep.c

@@ -585,7 +585,7 @@ moxie_frame_prev_register (const frame_info_ptr &this_frame,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind moxie_frame_unwind = {
+static const struct frame_unwind_legacy moxie_frame_unwind (
   "moxie prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -594,7 +594,7 @@ static const struct frame_unwind moxie_frame_unwind = {
   moxie_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Return the base address of this_frame.  */
 

gdb/msp430-tdep.c

@@ -542,7 +542,7 @@ msp430_prev_register (const frame_info_ptr &this_frame,
     return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind msp430_unwind = {
+static const struct frame_unwind_legacy msp430_unwind (
   "msp430 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -551,7 +551,7 @@ static const struct frame_unwind msp430_unwind = {
   msp430_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Implement the "dwarf2_reg_to_regnum" gdbarch method.  */
 

gdb/nds32-tdep.c

@@ -988,8 +988,7 @@ nds32_frame_prev_register (const frame_info_ptr &this_frame, void **this_cache,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind nds32_frame_unwind =
+static const struct frame_unwind_legacy nds32_frame_unwind (
-{
   "nds32 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -997,8 +996,8 @@ static const struct frame_unwind nds32_frame_unwind =
   nds32_frame_this_id,
   nds32_frame_prev_register,
   NULL,
-  default_frame_sniffer,
+  default_frame_sniffer
-};
+);
 
 /* Return the frame base address of *THIS_FRAME.  */
 
@@ -1373,8 +1372,7 @@ nds32_epilogue_frame_prev_register (const frame_info_ptr &this_frame,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind nds32_epilogue_frame_unwind =
+static const struct frame_unwind_legacy nds32_epilogue_frame_unwind (
-{
   "nds32 epilogue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1383,7 +1381,7 @@ static const struct frame_unwind nds32_epilogue_frame_unwind =
   nds32_epilogue_frame_prev_register,
   NULL,
   nds32_epilogue_frame_sniffer
-};
+);
 
 
 /* Floating type and struct type that has only one floating type member

gdb/or1k-tdep.c

@@ -1125,7 +1125,7 @@ or1k_frame_prev_register (const frame_info_ptr &this_frame,
 
 /* Data structures for the normal prologue-analysis-based unwinder.  */
 
-static const struct frame_unwind or1k_frame_unwind = {
+static const struct frame_unwind_legacy or1k_frame_unwind (
   "or1k prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1134,8 +1134,8 @@ static const struct frame_unwind or1k_frame_unwind = {
   or1k_frame_prev_register,
   NULL,
   default_frame_sniffer,
-  NULL,
+  NULL
-};
+);
 
 /* Architecture initialization for OpenRISC 1000.  */
 

gdb/ppc-fbsd-tdep.c

@@ -262,7 +262,7 @@ ppcfbsd_sigtramp_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_register (cache, this_frame, regnum);
 }
 
-static const struct frame_unwind ppcfbsd_sigtramp_frame_unwind = {
+static const struct frame_unwind_legacy ppcfbsd_sigtramp_frame_unwind (
   "ppc freebsd sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -271,7 +271,7 @@ static const struct frame_unwind ppcfbsd_sigtramp_frame_unwind = {
   ppcfbsd_sigtramp_frame_prev_register,
   NULL,
   ppcfbsd_sigtramp_frame_sniffer
-};
+);
 
 static enum return_value_convention
 ppcfbsd_return_value (struct gdbarch *gdbarch, struct value *function,

gdb/ppc-obsd-tdep.c

@@ -231,7 +231,7 @@ ppcobsd_sigtramp_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_register (cache, this_frame, regnum);
 }
 
-static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = {
+static const struct frame_unwind_legacy ppcobsd_sigtramp_frame_unwind (
   "ppc openbsd sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -240,7 +240,7 @@ static const struct frame_unwind ppcobsd_sigtramp_frame_unwind = {
   ppcobsd_sigtramp_frame_prev_register,
   NULL,
   ppcobsd_sigtramp_frame_sniffer
-};
+);
 
 
 static void

gdb/python/py-unwind.c

@@ -785,11 +785,35 @@ pending_framepy_level (PyObject *self, PyObject *args)
   return gdb_py_object_from_longest (level).release ();
 }
 
+/* Class for frame unwinders registered by the Python architecture callback.  */
+class frame_unwind_python : public frame_unwind
+{
+public:
+  frame_unwind_python (const struct frame_data *newarch)
+    : frame_unwind ("python", NORMAL_FRAME, FRAME_UNWIND_EXTENSION, newarch)
+  { }
+
+  /* No need to override stop_reason, we want the default.  */
+
+  int sniff (const frame_info_ptr &this_frame,
+	     void **this_prologue_cache) const override;
+
+  void this_id (const frame_info_ptr &this_frame, void **this_prologue_cache,
+		struct frame_id *id) const override;
+
+  struct value *prev_register (const frame_info_ptr &this_frame,
+			       void **this_prologue_cache,
+			       int regnum) const override;
+
+  void dealloc_cache (frame_info *self, void *this_cache) const override;
+};
+
 /* frame_unwind.this_id method.  */
 
-static void
+void
-pyuw_this_id (const frame_info_ptr &this_frame, void **cache_ptr,
+frame_unwind_python::this_id (const frame_info_ptr &this_frame,
-	      struct frame_id *this_id)
+			      void **cache_ptr,
+			      struct frame_id *this_id) const
 {
   *this_id = ((cached_frame_info *) *cache_ptr)->frame_id;
   pyuw_debug_printf ("frame_id: %s", this_id->to_string ().c_str ());
@@ -797,9 +821,9 @@ pyuw_this_id (const frame_info_ptr &this_frame, void **cache_ptr,
 
 /* frame_unwind.prev_register.  */
 
-static struct value *
+struct value *
-pyuw_prev_register (const frame_info_ptr &this_frame, void **cache_ptr,
+frame_unwind_python::prev_register (const frame_info_ptr &this_frame,
-		    int regnum)
+				    void **cache_ptr, int regnum) const
 {
   PYUW_SCOPED_DEBUG_ENTER_EXIT;
 
@@ -820,13 +844,13 @@ pyuw_prev_register (const frame_info_ptr &this_frame, void **cache_ptr,
 
 /* Frame sniffer dispatch.  */
 
-static int
+int
-pyuw_sniffer (const struct frame_unwind *self, const frame_info_ptr &this_frame,
+frame_unwind_python::sniff (const frame_info_ptr &this_frame,
-	      void **cache_ptr)
+			    void **cache_ptr) const
 {
   PYUW_SCOPED_DEBUG_ENTER_EXIT;
 
-  struct gdbarch *gdbarch = (struct gdbarch *) (self->unwind_data);
+  struct gdbarch *gdbarch = (struct gdbarch *) (this->unwind_data ());
   cached_frame_info *cached_frame;
 
   gdbpy_enter enter_py (gdbarch);
@@ -948,8 +972,8 @@ pyuw_sniffer (const struct frame_unwind *self, const frame_info_ptr &this_frame,
 
 /* Frame cache release shim.  */
 
-static void
+void
-pyuw_dealloc_cache (frame_info *this_frame, void *cache)
+frame_unwind_python::dealloc_cache (frame_info *this_frame, void *cache) const
 {
   PYUW_SCOPED_DEBUG_ENTER_EXIT;
   cached_frame_info *cached_frame = (cached_frame_info *) cache;
@@ -981,17 +1005,9 @@ pyuw_on_new_gdbarch (gdbarch *newarch)
   if (!data->unwinder_registered)
     {
       struct frame_unwind *unwinder
-	  = GDBARCH_OBSTACK_ZALLOC (newarch, struct frame_unwind);
+	  = obstack_new<frame_unwind_python>
+	    (gdbarch_obstack (newarch), (const struct frame_data *) newarch);
 
-      unwinder->name = "python";
-      unwinder->type = NORMAL_FRAME;
-      unwinder->unwinder_class = FRAME_UNWIND_EXTENSION;
-      unwinder->stop_reason = default_frame_unwind_stop_reason;
-      unwinder->this_id = pyuw_this_id;
-      unwinder->prev_register = pyuw_prev_register;
-      unwinder->unwind_data = (const struct frame_data *) newarch;
-      unwinder->sniffer = pyuw_sniffer;
-      unwinder->dealloc_cache = pyuw_dealloc_cache;
       frame_unwind_prepend_unwinder (newarch, unwinder);
       data->unwinder_registered = 1;
     }

gdb/record-btrace.c

@@ -1941,8 +1941,7 @@ record_btrace_frame_dealloc_cache (frame_info *self, void *this_cache)
    Therefore this unwinder reports any possibly unwound registers as
    <unavailable>.  */
 
-const struct frame_unwind record_btrace_frame_unwind =
+const struct frame_unwind_legacy record_btrace_frame_unwind (
-{
   "record-btrace",
   NORMAL_FRAME,
   FRAME_UNWIND_GDB,
@@ -1952,10 +1951,9 @@ const struct frame_unwind record_btrace_frame_unwind =
   NULL,
   record_btrace_frame_sniffer,
   record_btrace_frame_dealloc_cache
-};
+);
 
-const struct frame_unwind record_btrace_tailcall_frame_unwind =
+const struct frame_unwind_legacy record_btrace_tailcall_frame_unwind (
-{
   "record-btrace tailcall",
   TAILCALL_FRAME,
   FRAME_UNWIND_GDB,
@@ -1965,7 +1963,7 @@ const struct frame_unwind record_btrace_tailcall_frame_unwind =
   NULL,
   record_btrace_tailcall_frame_sniffer,
   record_btrace_frame_dealloc_cache
-};
+);
 
 /* Implement the get_unwinder method.  */
 

gdb/record.h

@@ -36,8 +36,8 @@ extern struct cmd_list_element *show_record_cmdlist;
 extern struct cmd_list_element *info_record_cmdlist;
 
 /* Unwinders for some record targets.  */
-extern const struct frame_unwind record_btrace_frame_unwind;
+extern const struct frame_unwind_legacy record_btrace_frame_unwind;
-extern const struct frame_unwind record_btrace_tailcall_frame_unwind;
+extern const struct frame_unwind_legacy record_btrace_tailcall_frame_unwind;
 
 /* A list of different recording methods.  */
 enum record_method

gdb/riscv-tdep.c

@@ -3904,8 +3904,7 @@ riscv_frame_prev_register (const frame_info_ptr &this_frame,
    are the fallback unwinder (DWARF unwinder is used first), we use the
    default frame sniffer, which always accepts the frame.  */
 
-static const struct frame_unwind riscv_frame_unwind =
+static const struct frame_unwind_legacy riscv_frame_unwind (
-{
   /*.name          =*/ "riscv prologue",
   /*.type          =*/ NORMAL_FRAME,
   /*.unwinder_class=*/FRAME_UNWIND_ARCH,
@@ -3915,8 +3914,8 @@ static const struct frame_unwind riscv_frame_unwind =
   /*.unwind_data   =*/ NULL,
   /*.sniffer       =*/ default_frame_sniffer,
   /*.dealloc_cache =*/ NULL,
-  /*.prev_arch     =*/ NULL,
+  /*.prev_arch     =*/ NULL
-};
+);
 
 /* Extract a set of required target features out of ABFD.  If ABFD is
    nullptr then a RISCV_GDBARCH_FEATURES is returned in its default state.  */

gdb/rl78-tdep.c

@@ -1183,8 +1183,7 @@ rl78_prev_register (const frame_info_ptr &this_frame,
     return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind rl78_unwind =
+static const struct frame_unwind_legacy rl78_unwind (
-{
   "rl78 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1193,7 +1192,7 @@ static const struct frame_unwind rl78_unwind =
   rl78_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Implement the "dwarf_reg_to_regnum" gdbarch method.  */
 

gdb/rs6000-aix-tdep.c

@@ -328,7 +328,7 @@ aix_sighandle_frame_sniffer (const struct frame_unwind *self,
 
 /* AIX signal handler frame unwinder */
 
-static const struct frame_unwind aix_sighandle_frame_unwind = {
+static const struct frame_unwind_legacy aix_sighandle_frame_unwind (
   "rs6000 aix sighandle",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -337,7 +337,7 @@ static const struct frame_unwind aix_sighandle_frame_unwind = {
   aix_sighandle_frame_prev_register,
   NULL,
   aix_sighandle_frame_sniffer
-};
+);
 
 /* Core file support.  */
 

gdb/rs6000-tdep.c

@@ -3837,8 +3837,7 @@ rs6000_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_prev_register (this_frame, info->saved_regs, regnum);
 }
 
-static const struct frame_unwind rs6000_frame_unwind =
+static const struct frame_unwind_legacy rs6000_frame_unwind (
-{
   "rs6000 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3847,7 +3846,7 @@ static const struct frame_unwind rs6000_frame_unwind =
   rs6000_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Allocate and initialize a frame cache for an epilogue frame.
    SP is restored and prev-PC is stored in LR.  */
@@ -3979,8 +3978,7 @@ rs6000_epilogue_frame_sniffer (const struct frame_unwind *self,
 /* Frame unwinder for epilogue frame.  This is required for reverse step-over
    a function without debug information.  */
 
-static const struct frame_unwind rs6000_epilogue_frame_unwind =
+static const struct frame_unwind_legacy rs6000_epilogue_frame_unwind (
-{
   "rs6000 epilogue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -3988,7 +3986,7 @@ static const struct frame_unwind rs6000_epilogue_frame_unwind =
   rs6000_epilogue_frame_this_id, rs6000_epilogue_frame_prev_register,
   NULL,
   rs6000_epilogue_frame_sniffer
-};
+);
 
 
 static CORE_ADDR

gdb/rx-tdep.c

@@ -631,7 +631,7 @@ rx_exception_sniffer (const struct frame_unwind *self,
 /* Data structure for normal code using instruction-based prologue
    analyzer.  */
 
-static const struct frame_unwind rx_frame_unwind = {
+static const struct frame_unwind_legacy rx_frame_unwind (
   "rx prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -640,12 +640,12 @@ static const struct frame_unwind rx_frame_unwind = {
   rx_frame_prev_register,
   NULL,
   rx_frame_sniffer
-};
+);
 
 /* Data structure for exception code using instruction-based prologue
    analyzer.  */
 
-static const struct frame_unwind rx_exception_unwind = {
+static const struct frame_unwind_legacy rx_exception_unwind (
   "rx exception",
   /* SIGTRAMP_FRAME could be used here, but backtraces are less informative.  */
   NORMAL_FRAME,
@@ -655,7 +655,7 @@ static const struct frame_unwind rx_exception_unwind = {
   rx_frame_prev_register,
   NULL,
   rx_exception_sniffer
-};
+);
 
 /* Implement the "push_dummy_call" gdbarch method.  */
 static CORE_ADDR

gdb/s12z-tdep.c

@@ -441,7 +441,7 @@ s12z_frame_prev_register (const frame_info_ptr &this_frame,
 }
 
 /* Data structures for the normal prologue-analysis-based unwinder.  */
-static const struct frame_unwind s12z_frame_unwind = {
+static const struct frame_unwind_legacy s12z_frame_unwind (
   "s12z prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -450,8 +450,8 @@ static const struct frame_unwind s12z_frame_unwind = {
   s12z_frame_prev_register,
   NULL,
   default_frame_sniffer,
-  NULL,
+  NULL
-};
+);
 
 
 constexpr gdb_byte s12z_break_insn[] = {0x00};

gdb/s390-linux-tdep.c

@@ -541,7 +541,7 @@ s390_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
 /* S390 sigtramp frame unwinder.  */
 
-static const struct frame_unwind s390_sigtramp_frame_unwind = {
+static const struct frame_unwind_legacy s390_sigtramp_frame_unwind (
   "s390 linux sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -550,7 +550,7 @@ static const struct frame_unwind s390_sigtramp_frame_unwind = {
   s390_sigtramp_frame_prev_register,
   NULL,
   s390_sigtramp_frame_sniffer
-};
+);
 
 /* Syscall handling.  */
 

gdb/s390-tdep.c

@@ -2764,7 +2764,7 @@ s390_frame_prev_register (const frame_info_ptr &this_frame,
 
 /* Default S390 frame unwinder.  */
 
-static const struct frame_unwind s390_frame_unwind = {
+static const struct frame_unwind_legacy s390_frame_unwind (
   "s390 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2773,7 +2773,7 @@ static const struct frame_unwind s390_frame_unwind = {
   s390_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 /* Code stubs and their stack frames.  For things like PLTs and NULL
    function calls (where there is no true frame and the return address
@@ -2859,7 +2859,7 @@ s390_stub_frame_sniffer (const struct frame_unwind *self,
 
 /* S390 stub frame unwinder.  */
 
-static const struct frame_unwind s390_stub_frame_unwind = {
+static const struct frame_unwind_legacy s390_stub_frame_unwind (
   "s390 stub",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2868,7 +2868,7 @@ static const struct frame_unwind s390_stub_frame_unwind = {
   s390_stub_frame_prev_register,
   NULL,
   s390_stub_frame_sniffer
-};
+);
 
 /* Frame base handling.  */
 

gdb/sentinel-frame.c

@@ -78,8 +78,7 @@ sentinel_frame_prev_arch (const frame_info_ptr &this_frame,
   return cache->regcache->arch ();
 }
 
-const struct frame_unwind sentinel_frame_unwind =
+const struct frame_unwind_legacy sentinel_frame_unwind (
-{
   "sentinel",
   SENTINEL_FRAME,
   FRAME_UNWIND_GDB,
@@ -89,5 +88,5 @@ const struct frame_unwind sentinel_frame_unwind =
   NULL,
   NULL,
   NULL,
-  sentinel_frame_prev_arch,
+  sentinel_frame_prev_arch
-};
+);

gdb/sentinel-frame.h

@@ -34,6 +34,6 @@ extern void *sentinel_frame_cache (struct regcache *regcache);
 
 /* At present there is only one type of sentinel frame.  */
 
-extern const struct frame_unwind sentinel_frame_unwind;
+extern const struct frame_unwind_legacy sentinel_frame_unwind;
 
 #endif /* GDB_SENTINEL_FRAME_H */

gdb/sh-tdep.c

@@ -1950,7 +1950,7 @@ sh_frame_this_id (const frame_info_ptr &this_frame, void **this_cache,
   *this_id = frame_id_build (cache->saved_sp, cache->pc);
 }
 
-static const struct frame_unwind sh_frame_unwind = {
+static const struct frame_unwind_legacy sh_frame_unwind (
   "sh prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1959,7 +1959,7 @@ static const struct frame_unwind sh_frame_unwind = {
   sh_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 sh_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)
@@ -2017,8 +2017,7 @@ sh_stub_unwind_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind sh_stub_unwind =
+static const struct frame_unwind_legacy sh_stub_unwind (
-{
   "sh stub",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -2027,7 +2026,7 @@ static const struct frame_unwind sh_stub_unwind =
   sh_frame_prev_register,
   NULL,
   sh_stub_unwind_sniffer
-};
+);
 
 /* Implement the stack_frame_destroyed_p gdbarch method.
 

gdb/sparc-netbsd-tdep.c

@@ -248,8 +248,7 @@ sparc32nbsd_sigcontext_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind sparc32nbsd_sigcontext_frame_unwind =
+static const struct frame_unwind_legacy sparc32nbsd_sigcontext_frame_unwind (
-{
   "sparc32 netbsd sigcontext",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -258,7 +257,7 @@ static const struct frame_unwind sparc32nbsd_sigcontext_frame_unwind =
   sparc32nbsd_sigcontext_frame_prev_register,
   NULL,
   sparc32nbsd_sigcontext_frame_sniffer
-};
+);
 
 /* Return the address of a system call's alternative return
    address.  */

gdb/sparc-obsd-tdep.c

@@ -134,8 +134,7 @@ sparc32obsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
   return 0;
 }
-static const struct frame_unwind sparc32obsd_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy sparc32obsd_sigtramp_frame_unwind (
-{
   "sparc32 openbsd sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -144,7 +143,7 @@ static const struct frame_unwind sparc32obsd_sigtramp_frame_unwind =
   sparc32obsd_sigtramp_frame_prev_register,
   NULL,
   sparc32obsd_sigtramp_frame_sniffer
-};
+);
 
 
 

gdb/sparc-sol2-tdep.c

@@ -179,8 +179,7 @@ sparc32_sol2_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return sol2_sigtramp_p (this_frame);
 }
 
-static const struct frame_unwind sparc32_sol2_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy sparc32_sol2_sigtramp_frame_unwind (
-{
   "sparc32 solaris sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -189,7 +188,7 @@ static const struct frame_unwind sparc32_sol2_sigtramp_frame_unwind =
   sparc32_sol2_sigtramp_frame_prev_register,
   NULL,
   sparc32_sol2_sigtramp_frame_sniffer
-};
+);
 
 
 

gdb/sparc-tdep.c

@@ -1346,8 +1346,7 @@ sparc32_frame_prev_register (const frame_info_ptr &this_frame,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind sparc32_frame_unwind =
+static const struct frame_unwind_legacy sparc32_frame_unwind (
-{
   "sparc32 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1356,7 +1355,7 @@ static const struct frame_unwind sparc32_frame_unwind =
   sparc32_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 
 static CORE_ADDR

gdb/sparc64-fbsd-tdep.c

@@ -196,8 +196,7 @@ sparc64fbsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind sparc64fbsd_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy sparc64fbsd_sigtramp_frame_unwind (
-{
   "sparc64 freebsd sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -206,7 +205,7 @@ static const struct frame_unwind sparc64fbsd_sigtramp_frame_unwind =
   sparc64fbsd_sigtramp_frame_prev_register,
   NULL,
   sparc64fbsd_sigtramp_frame_sniffer
-};
+);
 
 
 static const struct regset sparc64fbsd_gregset =

gdb/sparc64-netbsd-tdep.c

@@ -222,8 +222,7 @@ sparc64nbsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind sparc64nbsd_sigcontext_frame_unwind =
+static const struct frame_unwind_legacy sparc64nbsd_sigcontext_frame_unwind (
-{
   "sparc64 netbsd sigcontext",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -232,7 +231,7 @@ static const struct frame_unwind sparc64nbsd_sigcontext_frame_unwind =
   sparc64nbsd_sigcontext_frame_prev_register,
   NULL,
   sparc64nbsd_sigtramp_frame_sniffer
-};
+);
 
 
 static const struct regset sparc64nbsd_gregset =

gdb/sparc64-obsd-tdep.c

@@ -220,8 +220,7 @@ sparc64obsd_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind sparc64obsd_frame_unwind =
+static const struct frame_unwind_legacy sparc64obsd_frame_unwind (
-{
   "sparc64 openbsd sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -230,7 +229,7 @@ static const struct frame_unwind sparc64obsd_frame_unwind =
   sparc64obsd_frame_prev_register,
   NULL,
   sparc64obsd_sigtramp_frame_sniffer
-};
+);
 
 /* Kernel debugging support.  */
 
@@ -305,8 +304,7 @@ sparc64obsd_trapframe_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind sparc64obsd_trapframe_unwind =
+static const struct frame_unwind_legacy sparc64obsd_trapframe_unwind (
-{
   "sparc64 openbsd trap",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -315,7 +313,7 @@ static const struct frame_unwind sparc64obsd_trapframe_unwind =
   sparc64obsd_trapframe_prev_register,
   NULL,
   sparc64obsd_trapframe_sniffer
-};
+);
 
 
 /* Threads support.  */

gdb/sparc64-sol2-tdep.c

@@ -182,8 +182,7 @@ sparc64_sol2_sigtramp_frame_sniffer (const struct frame_unwind *self,
   return sol2_sigtramp_p (this_frame);
 }
 
-static const struct frame_unwind sparc64_sol2_sigtramp_frame_unwind =
+static const struct frame_unwind_legacy sparc64_sol2_sigtramp_frame_unwind (
-{
   "sparc64 solaris sigtramp",
   SIGTRAMP_FRAME,
   FRAME_UNWIND_ARCH,
@@ -192,7 +191,7 @@ static const struct frame_unwind sparc64_sol2_sigtramp_frame_unwind =
   sparc64_sol2_sigtramp_frame_prev_register,
   NULL,
   sparc64_sol2_sigtramp_frame_sniffer
-};
+);
 
 
 

gdb/sparc64-tdep.c

@@ -1135,8 +1135,7 @@ sparc64_frame_prev_register (const frame_info_ptr &this_frame, void **this_cache
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static const struct frame_unwind sparc64_frame_unwind =
+static const struct frame_unwind_legacy sparc64_frame_unwind (
-{
   "sparc64 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1145,7 +1144,7 @@ static const struct frame_unwind sparc64_frame_unwind =
   sparc64_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 
 static CORE_ADDR

gdb/tic6x-tdep.c

@@ -452,8 +452,7 @@ tic6x_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)
   return info->base;
 }
 
-static const struct frame_unwind tic6x_frame_unwind =
+static const struct frame_unwind_legacy tic6x_frame_unwind (
-{
   "tic6x prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -462,7 +461,7 @@ static const struct frame_unwind tic6x_frame_unwind =
   tic6x_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static const struct frame_base tic6x_frame_base =
 {
@@ -516,8 +515,7 @@ tic6x_stub_unwind_sniffer (const struct frame_unwind *self,
   return 0;
 }
 
-static const struct frame_unwind tic6x_stub_unwind =
+static const struct frame_unwind_legacy tic6x_stub_unwind (
-{
   "tic6x stub",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -526,7 +524,7 @@ static const struct frame_unwind tic6x_stub_unwind =
   tic6x_frame_prev_register,
   NULL,
   tic6x_stub_unwind_sniffer
-};
+);
 
 /* Return the instruction on address PC.  */
 

gdb/tilegx-tdep.c

@@ -900,7 +900,7 @@ tilegx_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)
   return cache->base;
 }
 
-static const struct frame_unwind tilegx_frame_unwind = {
+static const struct frame_unwind_legacy tilegx_frame_unwind (
   "tilegx prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -910,7 +910,7 @@ static const struct frame_unwind tilegx_frame_unwind = {
   NULL,                        /* const struct frame_data *unwind_data  */
   default_frame_sniffer,       /* frame_sniffer_ftype *sniffer  */
   NULL                         /* frame_prev_pc_ftype *prev_pc  */
-};
+);
 
 static const struct frame_base tilegx_frame_base = {
   &tilegx_frame_unwind,

gdb/tramp-frame.c

@@ -57,10 +57,41 @@ tramp_frame_cache (const frame_info_ptr &this_frame,
   return tramp_cache->trad_cache;
 }
 
-static void
+class frame_unwind_trampoline : public frame_unwind
-tramp_frame_this_id (const frame_info_ptr &this_frame,
+{
+public:
+  frame_unwind_trampoline (enum frame_type type, const struct frame_data *data,
+			   frame_prev_arch_ftype *prev_arch_func)
+    : frame_unwind ("trampoline", type, FRAME_UNWIND_GDB, data),
+      m_prev_arch (prev_arch_func)
+  { }
+
+  int sniff (const frame_info_ptr &this_frame,
+	     void **this_prologue_cache) const override;
+
+  void this_id (const frame_info_ptr &this_frame, void **this_prologue_cache,
+		struct frame_id *id) const override;
+
+  value *prev_register (const frame_info_ptr &this_frame,
+			void **this_prologue_cache,
+			int regnum) const override;
+
+  struct gdbarch *prev_arch (const frame_info_ptr &this_frame,
+			     void **this_prologue_cache) const override
+  {
+    if (m_prev_arch == nullptr)
+      return frame_unwind::prev_arch (this_frame, this_prologue_cache);
+    return m_prev_arch (this_frame, this_prologue_cache);
+  }
+
+private:
+  frame_prev_arch_ftype *m_prev_arch;
+};
+
+void
+frame_unwind_trampoline::this_id (const frame_info_ptr &this_frame,
 				  void **this_cache,
-		     struct frame_id *this_id)
+				  struct frame_id *this_id) const
 {
   struct trad_frame_cache *trad_cache
     = tramp_frame_cache (this_frame, this_cache);
@@ -68,10 +99,10 @@ tramp_frame_this_id (const frame_info_ptr &this_frame,
   trad_frame_get_id (trad_cache, this_id);
 }
 
-static struct value *
+struct value *
-tramp_frame_prev_register (const frame_info_ptr &this_frame,
+frame_unwind_trampoline::prev_register (const frame_info_ptr &this_frame,
 					void **this_cache,
-			   int prev_regnum)
+					int prev_regnum) const
 {
   struct trad_frame_cache *trad_cache
     = tramp_frame_cache (this_frame, this_cache);
@@ -119,12 +150,11 @@ tramp_frame_start (const struct tramp_frame *tramp,
   return 0;
 }
 
-static int
+int
-tramp_frame_sniffer (const struct frame_unwind *self,
+frame_unwind_trampoline::sniff (const frame_info_ptr &this_frame,
-		     const frame_info_ptr &this_frame,
+				void **this_cache) const
-		     void **this_cache)
 {
-  const struct tramp_frame *tramp = self->unwind_data->tramp_frame;
+  const struct tramp_frame *tramp = unwind_data ()->tramp_frame;
   CORE_ADDR pc = get_frame_pc (this_frame);
   CORE_ADDR func;
   struct tramp_frame_cache *tramp_cache;
@@ -161,16 +191,11 @@ tramp_frame_prepend_unwinder (struct gdbarch *gdbarch,
   gdb_assert (tramp_frame->insn_size <= sizeof (tramp_frame->insn[0].bytes));
 
   data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data);
-  unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind);
-
   data->tramp_frame = tramp_frame;
-  unwinder->type = tramp_frame->frame_type;
+
-  unwinder->unwind_data = data;
+  unwinder = obstack_new <frame_unwind_trampoline> (gdbarch_obstack (gdbarch),
-  unwinder->unwinder_class = FRAME_UNWIND_GDB;
+						    tramp_frame->frame_type,
-  unwinder->sniffer = tramp_frame_sniffer;
+						    data,
-  unwinder->stop_reason = default_frame_unwind_stop_reason;
+						    tramp_frame->prev_arch);
-  unwinder->this_id = tramp_frame_this_id;
-  unwinder->prev_register = tramp_frame_prev_register;
-  unwinder->prev_arch = tramp_frame->prev_arch;
   frame_unwind_prepend_unwinder (gdbarch, unwinder);
 }

gdb/v850-tdep.c

@@ -1320,7 +1320,7 @@ v850_frame_this_id (const frame_info_ptr &this_frame, void **this_cache,
   *this_id = frame_id_build (cache->saved_regs[E_SP_REGNUM].addr (), cache->pc);
 }
 
-static const struct frame_unwind v850_frame_unwind = {
+static const struct frame_unwind_legacy v850_frame_unwind (
   "v850 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1329,7 +1329,7 @@ static const struct frame_unwind v850_frame_unwind = {
   v850_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 v850_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/vax-tdep.c

@@ -386,8 +386,7 @@ vax_frame_prev_register (const frame_info_ptr &this_frame,
   return trad_frame_get_prev_register (this_frame, cache->saved_regs, regnum);
 }
 
-static const struct frame_unwind vax_frame_unwind =
+static const struct frame_unwind_legacy vax_frame_unwind (
-{
   "vax prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -396,7 +395,7 @@ static const struct frame_unwind vax_frame_unwind =
   vax_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 
 static CORE_ADDR

gdb/windows-tdep.c

@@ -1321,10 +1321,9 @@ cygwin_sigwrapper_frame_cache (frame_info_ptr this_frame, void **this_cache)
   return cache;
 }
 
-static struct value *
+struct value *
-cygwin_sigwrapper_frame_prev_register (const frame_info_ptr &this_frame,
+cygwin_sigwrapper_frame_unwind::prev_register
-				       void **this_cache,
+    (const frame_info_ptr &this_frame, void **this_cache, int regnum) const
-				       int regnum)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
   struct cygwin_sigwrapper_frame_cache *cache
@@ -1340,20 +1339,18 @@ cygwin_sigwrapper_frame_prev_register (const frame_info_ptr &this_frame,
   return frame_unwind_got_register (this_frame, regnum, regnum);
 }
 
-static void
+void
-cygwin_sigwrapper_frame_this_id (const frame_info_ptr &this_frame,
+cygwin_sigwrapper_frame_unwind::this_id (const frame_info_ptr &this_frame,
 					 void **this_cache,
-				 struct frame_id *this_id)
+					 struct frame_id *this_id) const
 {
   *this_id = frame_id_build_unavailable_stack (get_frame_func (this_frame));
 }
 
-static int
+int
-cygwin_sigwrapper_frame_sniffer (const struct frame_unwind *self_,
+cygwin_sigwrapper_frame_unwind::sniff (const frame_info_ptr &this_frame,
-				 const frame_info_ptr &this_frame,
+					 void **this_cache) const
-				 void **this_cache)
 {
-  const auto *self = (const struct cygwin_sigwrapper_frame_unwind *) self_;
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
 
   CORE_ADDR pc = get_frame_pc (this_frame);
@@ -1376,7 +1373,7 @@ cygwin_sigwrapper_frame_sniffer (const struct frame_unwind *self_,
 		      paddress (gdbarch, end));
 
   int tlsoffset;
-  cygwin_sigwrapper_frame_analyze (gdbarch, start, end, self->patterns_list,
+  cygwin_sigwrapper_frame_analyze (gdbarch, start, end, patterns_list,
 				   &tlsoffset);
   if (tlsoffset == 0)
     return 0;
@@ -1396,13 +1393,7 @@ cygwin_sigwrapper_frame_sniffer (const struct frame_unwind *self_,
 
 cygwin_sigwrapper_frame_unwind::cygwin_sigwrapper_frame_unwind
   (gdb::array_view<const gdb::array_view<const gdb_byte>> patterns_list)
-    : frame_unwind (),
+    : frame_unwind ("cygwin sigwrapper", NORMAL_FRAME, FRAME_UNWIND_GDB,
-      patterns_list (patterns_list)
+		    nullptr), patterns_list (patterns_list)
 {
-  name = "cygwin sigwrapper";
-  type = NORMAL_FRAME;
-  stop_reason = default_frame_unwind_stop_reason;
-  this_id = cygwin_sigwrapper_frame_this_id;
-  prev_register = cygwin_sigwrapper_frame_prev_register;
-  sniffer = cygwin_sigwrapper_frame_sniffer;
 }

gdb/windows-tdep.h

@@ -60,8 +60,9 @@ extern bool is_linked_with_cygwin_dll (bfd *abfd);
 /* Cygwin sigwapper unwinder.  Unwinds signal frames over
    sigbe/sigdelayed.  */
 
-struct cygwin_sigwrapper_frame_unwind : public frame_unwind
+class cygwin_sigwrapper_frame_unwind : public frame_unwind
 {
+public:
   explicit cygwin_sigwrapper_frame_unwind
     (gdb::array_view<const gdb::array_view<const gdb_byte>> patterns_list);
 
@@ -73,6 +74,19 @@ struct cygwin_sigwrapper_frame_unwind : public frame_unwind
      If any pattern in the list matches, then the frame is assumed to
      be a sigwrapper frame.  */
   gdb::array_view<const gdb::array_view<const gdb_byte>> patterns_list;
+
+  /* Calculate the frame ID of a cygwin wrapper.  */
+  void this_id (const frame_info_ptr &this_frame, void **this_prologue_cache,
+		struct frame_id *id) const override;
+
+  /* Sniff the frame to tell if this unwinder should be used.  */
+  int sniff (const frame_info_ptr &this_frame,
+	       void **this_prologue_cache) const override;
+
+  /* Calculate the value of a given register in the previous frame.  */
+  struct value *prev_register (const frame_info_ptr &this_frame,
+			       void **this_cache,
+			       int regnum) const override;
 };
 
 #endif /* GDB_WINDOWS_TDEP_H */

gdb/xstormy16-tdep.c

@@ -728,7 +728,7 @@ xstormy16_frame_base_address (const frame_info_ptr &this_frame, void **this_cach
   return cache->base;
 }
 
-static const struct frame_unwind xstormy16_frame_unwind = {
+static const struct frame_unwind_legacy xstormy16_frame_unwind (
   "xstormy16 prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -737,7 +737,7 @@ static const struct frame_unwind xstormy16_frame_unwind = {
   xstormy16_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static const struct frame_base xstormy16_frame_base = {
   &xstormy16_frame_unwind,

gdb/xtensa-tdep.c

@@ -1496,9 +1496,7 @@ xtensa_frame_prev_register (const frame_info_ptr &this_frame,
 }
 
 
-static const struct frame_unwind
+static const struct frame_unwind_legacy xtensa_unwind (
-xtensa_unwind =
-{
   "xtensa prologue",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1507,7 +1505,7 @@ xtensa_unwind =
   xtensa_frame_prev_register,
   NULL,
   default_frame_sniffer
-};
+);
 
 static CORE_ADDR
 xtensa_frame_base_address (const frame_info_ptr &this_frame, void **this_cache)

gdb/z80-tdep.c

@@ -1063,9 +1063,7 @@ z80_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr)
   return 0;
 }
 
-static const struct frame_unwind
+static const struct frame_unwind_legacy z80_frame_unwind (
-z80_frame_unwind =
-{
   "z80",
   NORMAL_FRAME,
   FRAME_UNWIND_ARCH,
@@ -1076,7 +1074,7 @@ z80_frame_unwind =
   default_frame_sniffer
   /*dealloc_cache*/
   /*prev_arch*/
-};
+);
 
 /* Initialize the gdbarch struct for the Z80 arch */
 static struct gdbarch *