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, 14 insertions, 12 deletions

diff --git a/gdb/alpha-tdep.c b/gdb/alpha-tdep.c
index 03935d1..760a18a 100644
--- a/gdb/alpha-tdep.c
+++ b/gdb/alpha-tdep.c
@@ -615,11 +615,12 @@ alpha_return_value (struct gdbarch *gdbarch, struct value *function,
 		    gdb_byte *readbuf, const gdb_byte *writebuf)
 {
   enum type_code code = type->code ();
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if ((code == TYPE_CODE_STRUCT
        || code == TYPE_CODE_UNION
        || code == TYPE_CODE_ARRAY)
-      && gdbarch_tdep (gdbarch)->return_in_memory (type))
+      && tdep->return_in_memory (type))
     {
       if (readbuf)
 	{
@@ -850,7 +851,7 @@ static int
 alpha_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR jb_addr;
   gdb_byte raw_buffer[ALPHA_REGISTER_SIZE];
@@ -882,7 +883,6 @@ alpha_sigtramp_frame_unwind_cache (struct frame_info *this_frame,
 				   void **this_prologue_cache)
 {
   struct alpha_sigtramp_unwind_cache *info;
-  struct gdbarch_tdep *tdep;
 
   if (*this_prologue_cache)
     return (struct alpha_sigtramp_unwind_cache *) *this_prologue_cache;
@@ -890,7 +890,8 @@ alpha_sigtramp_frame_unwind_cache (struct frame_info *this_frame,
   info = FRAME_OBSTACK_ZALLOC (struct alpha_sigtramp_unwind_cache);
   *this_prologue_cache = info;
 
-  tdep = gdbarch_tdep (get_frame_arch (this_frame));
+  gdbarch *arch = get_frame_arch (this_frame);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (arch);
   info->sigcontext_addr = tdep->sigcontext_addr (this_frame);
 
   return info;
@@ -903,7 +904,7 @@ static CORE_ADDR
 alpha_sigtramp_register_address (struct gdbarch *gdbarch,
 				 CORE_ADDR sigcontext_addr, int regnum)
 { 
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (regnum >= 0 && regnum < 32)
     return sigcontext_addr + tdep->sc_regs_offset + regnum * 8;
@@ -924,7 +925,7 @@ alpha_sigtramp_frame_this_id (struct frame_info *this_frame,
 			      struct frame_id *this_id)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   struct alpha_sigtramp_unwind_cache *info
     = alpha_sigtramp_frame_unwind_cache (this_frame, this_prologue_cache);
   CORE_ADDR stack_addr, code_addr;
@@ -999,14 +1000,16 @@ alpha_sigtramp_frame_sniffer (const struct frame_unwind *self,
 
   /* We shouldn't even bother to try if the OSABI didn't register a
      sigcontext_addr handler or pc_in_sigtramp handler.  */
-  if (gdbarch_tdep (gdbarch)->sigcontext_addr == NULL)
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  if (tdep->sigcontext_addr == NULL)
     return 0;
-  if (gdbarch_tdep (gdbarch)->pc_in_sigtramp == NULL)
+
+  if (tdep->pc_in_sigtramp == NULL)
     return 0;
 
   /* Otherwise we should be in a signal frame.  */
   find_pc_partial_function (pc, &name, NULL, NULL);
-  if (gdbarch_tdep (gdbarch)->pc_in_sigtramp (gdbarch, pc, name))
+  if (tdep->pc_in_sigtramp (gdbarch, pc, name))
     return 1;
 
   return 0;
@@ -1038,7 +1041,7 @@ static int heuristic_fence_post = 0;
 static CORE_ADDR
 alpha_heuristic_proc_start (struct gdbarch *gdbarch, CORE_ADDR pc)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  alpha_gdbarch_tdep *tdep = (alpha_gdbarch_tdep *) gdbarch_tdep (gdbarch);
   CORE_ADDR last_non_nop = pc;
   CORE_ADDR fence = pc - heuristic_fence_post;
   CORE_ADDR orig_pc = pc;
@@ -1724,7 +1727,6 @@ alpha_software_single_step (struct regcache *regcache)
 static struct gdbarch *
 alpha_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
-  struct gdbarch_tdep *tdep;
   struct gdbarch *gdbarch;
 
   /* Find a candidate among extant architectures.  */
@@ -1732,7 +1734,7 @@ alpha_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   if (arches != NULL)
     return arches->gdbarch;
 
-  tdep = XCNEW (struct gdbarch_tdep);
+  alpha_gdbarch_tdep *tdep = new alpha_gdbarch_tdep;
   gdbarch = gdbarch_alloc (&info, tdep);
 
   /* Lowest text address.  This is used by heuristic_proc_start()