gdb: fix gdbarch_tdep ODR violation

I would like to be able to use non-trivial types in gdbarch_tdep types.
This is not possible at the moment (in theory), because of the one
definition rule.

To allow it, rename all gdbarch_tdep types to <arch>_gdbarch_tdep, and
make them inherit from a gdbarch_tdep base class.  The inheritance is
necessary to be able to pass pointers to all these <arch>_gdbarch_tdep
objects to gdbarch_alloc, which takes a pointer to gdbarch_tdep.

These objects are never deleted through a base class pointer, so I
didn't include a virtual destructor.  In the future, if gdbarch objects
deletable, I could imagine that the gdbarch_tdep objects could become
owned by the gdbarch objects, and then it would become useful to have a
virtual destructor (so that the gdbarch object can delete the owned
gdbarch_tdep object).  But that's not necessary right now.

It turns out that RISC-V already has a gdbarch_tdep that is
non-default-constructible, so that provides a good motivation for this
change.

Most changes are fairly straightforward, mostly needing to add some
casts all over the place.  There is however the xtensa architecture,
doing its own little weird thing to define its gdbarch_tdep.  I did my
best to adapt it, but I can't test those changes.

Change-Id: Ic001903f91ddd106bd6ca09a79dabe8df2d69f3b

1 files changed, 3 insertions, 4 deletions

diff --git a/gdb/nios2-tdep.c b/gdb/nios2-tdep.c
index be5544e..706b579 100644
--- a/gdb/nios2-tdep.c
+++ b/gdb/nios2-tdep.c
@@ -2098,7 +2098,7 @@ static CORE_ADDR
 nios2_get_next_pc (struct regcache *regcache, CORE_ADDR pc)
 {
   struct gdbarch *gdbarch = regcache->arch ();
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nios2_gdbarch_tdep *tdep = (nios2_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   unsigned long mach = gdbarch_bfd_arch_info (gdbarch)->mach;
   unsigned int insn;
   const struct nios2_opcode *op = nios2_fetch_insn (gdbarch, pc, &insn);
@@ -2221,7 +2221,7 @@ static int
 nios2_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  nios2_gdbarch_tdep *tdep = (nios2_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR jb_addr = get_frame_register_unsigned (frame, NIOS2_R4_REGNUM);
   gdb_byte buf[4];
@@ -2275,7 +2275,6 @@ static struct gdbarch *
 nios2_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   int i;
   tdesc_arch_data_up tdesc_data;
   const struct target_desc *tdesc = info.target_desc;
@@ -2313,7 +2312,7 @@ nios2_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 
   /* None found, create a new architecture from the information
      provided.  */
-  tdep = XCNEW (struct gdbarch_tdep);
+  nios2_gdbarch_tdep *tdep = new nios2_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* longjmp support not enabled by default.  */