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, 12 insertions, 11 deletions

diff --git a/gdb/or1k-tdep.c b/gdb/or1k-tdep.c
index 4c42e0242f3..346ee97c49b 100644
--- a/gdb/or1k-tdep.c
+++ b/gdb/or1k-tdep.c
@@ -62,11 +62,11 @@ show_or1k_debug (struct ui_file *file, int from_tty,
 
 /* The target-dependent structure for gdbarch.  */
 
-struct gdbarch_tdep
+struct or1k_gdbarch_tdep : gdbarch_tdep
 {
-  int bytes_per_word;
-  int bytes_per_address;
-  CGEN_CPU_DESC gdb_cgen_cpu_desc;
+  int bytes_per_word = 0;
+  int bytes_per_address = 0;
+  CGEN_CPU_DESC gdb_cgen_cpu_desc = nullptr;
 };
 
 /* Support functions for the architecture definition.  */
@@ -247,7 +247,8 @@ or1k_return_value (struct gdbarch *gdbarch, struct value *functype,
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   enum type_code rv_type = valtype->code ();
   unsigned int rv_size = TYPE_LENGTH (valtype);
-  int bpw = (gdbarch_tdep (gdbarch))->bytes_per_word;
+  or1k_gdbarch_tdep *tdep = (or1k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int bpw = tdep->bytes_per_word;
 
   /* Deal with struct/union as addresses.  If an array won't fit in a
      single register it is returned as address.  Anything larger than 2
@@ -351,7 +352,7 @@ or1k_delay_slot_p (struct gdbarch *gdbarch, CORE_ADDR pc)
 {
   const CGEN_INSN *insn;
   CGEN_FIELDS tmp_fields;
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  or1k_gdbarch_tdep *tdep = (or1k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   insn = cgen_lookup_insn (tdep->gdb_cgen_cpu_desc,
 			   NULL,
@@ -633,8 +634,9 @@ or1k_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   int heap_offset = 0;
   CORE_ADDR heap_sp = sp - 128;
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  int bpa = (gdbarch_tdep (gdbarch))->bytes_per_address;
-  int bpw = (gdbarch_tdep (gdbarch))->bytes_per_word;
+  or1k_gdbarch_tdep *tdep = (or1k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  int bpa = tdep->bytes_per_address;
+  int bpw = tdep->bytes_per_word;
   struct type *func_type = value_type (function);
 
   /* Return address */
@@ -1140,7 +1142,6 @@ static struct gdbarch *
 or1k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 {
   struct gdbarch *gdbarch;
-  struct gdbarch_tdep *tdep;
   const struct bfd_arch_info *binfo;
   tdesc_arch_data_up tdesc_data;
   const struct target_desc *tdesc = info.target_desc;
@@ -1155,7 +1156,7 @@ or1k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
      actually know which target we are talking to, but put in some defaults
      for now.  */
   binfo = info.bfd_arch_info;
-  tdep = XCNEW (struct gdbarch_tdep);
+  or1k_gdbarch_tdep *tdep = new or1k_gdbarch_tdep;
   tdep->bytes_per_word = binfo->bits_per_word / binfo->bits_per_byte;
   tdep->bytes_per_address = binfo->bits_per_address / binfo->bits_per_byte;
   gdbarch = gdbarch_alloc (&info, tdep);
@@ -1283,7 +1284,7 @@ or1k_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 or1k_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+  or1k_gdbarch_tdep *tdep = (or1k_gdbarch_tdep *) gdbarch_tdep (gdbarch);
 
   if (NULL == tdep)
     return; /* Nothing to report */