gdb: move the type cast into gdbarch_tdep

I built GDB for all targets on a x86-64/GNU-Linux system, and
then (accidentally) passed GDB a RISC-V binary, and asked GDB to "run"
the binary on the native target.  I got this error:

  (gdb) show architecture
  The target architecture is set to "auto" (currently "i386").
  (gdb) file /tmp/hello.rv32.exe
  Reading symbols from /tmp/hello.rv32.exe...
  (gdb) show architecture
  The target architecture is set to "auto" (currently "riscv:rv32").
  (gdb) run
  Starting program: /tmp/hello.rv32.exe
  ../../src/gdb/i387-tdep.c:596: internal-error: i387_supply_fxsave: Assertion `tdep->st0_regnum >= I386_ST0_REGNUM' failed.

What's going on here is this; initially the architecture is i386, this
is based on the default architecture, which is set based on the native
target.  After loading the RISC-V executable the architecture of the
current inferior is updated based on the architecture of the
executable.

When we "run", GDB does a fork & exec, with the inferior being
controlled through ptrace.  GDB sees an initial stop from the inferior
as soon as the inferior comes to life.  In response to this stop GDB
ends up calling save_stop_reason (linux-nat.c), which ends up trying
to read register from the inferior, to do this we end up calling
target_ops::fetch_registers, which, for the x86-64 native target,
calls amd64_linux_nat_target::fetch_registers.

After this I eventually end up in i387_supply_fxsave, different x86
based targets will end in different functions to fetch registers, but
it doesn't really matter which function we end up in, the problem is
this line, which is repeated in many places:

  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);

The problem here is that the ARCH in this line comes from the current
inferior, which, as we discussed above, will be a RISC-V gdbarch, the
tdep field will actually be of type riscv_gdbarch_tdep, not
i386_gdbarch_tdep.  After this cast we are relying on undefined
behaviour, in my case I happen to trigger an assert, but this might
not always be the case.

The thing I tried that exposed this problem was of course, trying to
start an executable of the wrong architecture on a native target.  I
don't think that the correct solution for this problem is to detect,
at the point of cast, that the gdbarch_tdep object is of the wrong
type, but, I did wonder, is there a way that we could protect
ourselves from incorrectly casting the gdbarch_tdep object?

I think that there is something we can do here, and this commit is the
first step in that direction, though no actual check is added by this
commit.

This commit can be split into two parts:

 (1) In gdbarch.h and arch-utils.c.  In these files I have modified
 gdbarch_tdep (the function) so that it now takes a template argument,
 like this:

    template<typename TDepType>
    static inline TDepType *
    gdbarch_tdep (struct gdbarch *gdbarch)
    {
      struct gdbarch_tdep *tdep = gdbarch_tdep_1 (gdbarch);
      return static_cast<TDepType *> (tdep);
    }

  After this change we are no better protected, but the cast is now
  done within the gdbarch_tdep function rather than at the call sites,
  this leads to the second, much larger change in this commit,

  (2) Everywhere gdbarch_tdep is called, we make changes like this:

    -  i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
    +  i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (arch);

There should be no functional change after this commit.

In the next commit I will build on this change to add an assertion in
gdbarch_tdep that checks we are casting to the correct type.

1 files changed, 55 insertions, 55 deletions

diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index 607d6de..d3b4fce 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -355,7 +355,7 @@ static void
 arm_cache_init (struct arm_prologue_cache *cache, struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   arm_cache_init (cache, gdbarch);
   cache->sp = get_frame_register_unsigned (frame, ARM_SP_REGNUM);
@@ -553,7 +553,7 @@ bool arm_unwind_secure_frames = true;
 int
 arm_psr_thumb_bit (struct gdbarch *gdbarch)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep->is_m)
     return XPSR_T;
@@ -665,7 +665,7 @@ arm_pc_is_thumb (struct gdbarch *gdbarch, CORE_ADDR memaddr)
   struct bound_minimal_symbol sym;
   char type;
   arm_displaced_step_copy_insn_closure *dsc = nullptr;
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (gdbarch_displaced_step_copy_insn_closure_by_addr_p (gdbarch))
     dsc = ((arm_displaced_step_copy_insn_closure * )
@@ -769,7 +769,7 @@ arm_pc_is_thumb (struct gdbarch *gdbarch, CORE_ADDR memaddr)
 static int
 arm_m_addr_is_magic (struct gdbarch *gdbarch, CORE_ADDR addr)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   if (tdep->have_sec_ext)
     {
       switch ((addr & 0xff000000))
@@ -811,7 +811,7 @@ arm_m_addr_is_magic (struct gdbarch *gdbarch, CORE_ADDR addr)
 static CORE_ADDR
 arm_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR val)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* On M-profile devices, do not strip the low bit from EXC_RETURN
      (the magic exception return address).  */
@@ -939,7 +939,7 @@ thumb_analyze_prologue (struct gdbarch *gdbarch,
 			CORE_ADDR start, CORE_ADDR limit,
 			struct arm_prologue_cache *cache)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
   int i;
@@ -1879,7 +1879,7 @@ arm_analyze_prologue (struct gdbarch *gdbarch,
   CORE_ADDR offset, current_pc;
   pv_t regs[ARM_FPS_REGNUM];
   CORE_ADDR unrecognized_pc = 0;
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* Search the prologue looking for instructions that set up the
      frame pointer, adjust the stack pointer, and save registers.
@@ -2127,7 +2127,7 @@ arm_scan_prologue (struct frame_info *this_frame,
   CORE_ADDR prologue_start, prologue_end;
   CORE_ADDR prev_pc = get_frame_pc (this_frame);
   CORE_ADDR block_addr = get_frame_address_in_block (this_frame);
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* Assume there is no frame until proven otherwise.  */
   cache->framereg = ARM_SP_REGNUM;
@@ -2232,7 +2232,7 @@ arm_make_prologue_cache (struct frame_info *this_frame)
     return cache;
 
   arm_gdbarch_tdep *tdep =
-    (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
 
   prev_sp = unwound_fp + cache->framesize;
   arm_cache_set_active_sp_value (cache, tdep, prev_sp);
@@ -2263,7 +2263,7 @@ arm_prologue_unwind_stop_reason (struct frame_info *this_frame,
   /* This is meant to halt the backtrace at "_start".  */
   pc = get_frame_pc (this_frame);
   gdbarch *arch = get_frame_arch (this_frame);
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (arch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (arch);
   if (pc <= tdep->lowest_pc)
     return UNWIND_OUTERMOST;
 
@@ -2291,7 +2291,7 @@ arm_prologue_this_id (struct frame_info *this_frame,
   cache = (struct arm_prologue_cache *) *this_cache;
 
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
 
   /* Use function start address as part of the frame ID.  If we cannot
      identify the start address (due to missing symbol information),
@@ -2318,7 +2318,7 @@ arm_prologue_prev_register (struct frame_info *this_frame,
     *this_cache = arm_make_prologue_cache (this_frame);
   cache = (struct arm_prologue_cache *) *this_cache;
 
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* If this frame has signed the return address, mark it as so.  */
   if (tdep->have_pacbti && cache->ra_signed_state.has_value ()
@@ -2986,7 +2986,7 @@ arm_exidx_fill_cache (struct frame_info *this_frame, gdb_byte *entry)
 
   /* We already got the previous SP.  */
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
   arm_cache_set_active_sp_value (cache, tdep, vsp);
 
   return cache;
@@ -3111,7 +3111,7 @@ arm_make_epilogue_frame_cache (struct frame_info *this_frame)
 
   /* Since we are in epilogue, the SP has been restored.  */
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
   arm_cache_set_active_sp_value (cache, tdep,
 				 get_frame_register_unsigned (this_frame,
 							      ARM_SP_REGNUM));
@@ -3150,7 +3150,7 @@ arm_epilogue_frame_this_id (struct frame_info *this_frame,
     func = pc;
 
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
   *this_id = frame_id_build (arm_cache_get_prev_sp_value (cache, tdep), pc);
 }
 
@@ -3274,7 +3274,7 @@ arm_make_stub_cache (struct frame_info *this_frame)
   arm_cache_init (cache, this_frame);
 
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
   arm_cache_set_active_sp_value (cache, tdep,
 				 get_frame_register_unsigned (this_frame,
 							      ARM_SP_REGNUM));
@@ -3296,7 +3296,7 @@ arm_stub_this_id (struct frame_info *this_frame,
   cache = (struct arm_prologue_cache *) *this_cache;
 
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
   *this_id = frame_id_build (arm_cache_get_prev_sp_value (cache, tdep),
 			     get_frame_pc (this_frame));
 }
@@ -3344,7 +3344,7 @@ static struct arm_prologue_cache *
 arm_m_exception_cache (struct frame_info *this_frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   struct arm_prologue_cache *cache;
   CORE_ADDR lr;
@@ -3655,7 +3655,7 @@ arm_m_exception_this_id (struct frame_info *this_frame,
 
   /* Our frame ID for a stub frame is the current SP and LR.  */
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
   *this_id = frame_id_build (arm_cache_get_prev_sp_value (cache, tdep),
 			     get_frame_pc (this_frame));
 }
@@ -3677,7 +3677,7 @@ arm_m_exception_prev_register (struct frame_info *this_frame,
 
   /* The value was already reconstructed into PREV_SP.  */
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
   if (prev_regnum == ARM_SP_REGNUM)
     return frame_unwind_got_constant (this_frame, prev_regnum,
 				      arm_cache_get_prev_sp_value (cache, tdep));
@@ -3765,7 +3765,7 @@ arm_normal_frame_base (struct frame_info *this_frame, void **this_cache)
   cache = (struct arm_prologue_cache *) *this_cache;
 
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (get_frame_arch (this_frame));
+    = gdbarch_tdep<arm_gdbarch_tdep> (get_frame_arch (this_frame));
   return arm_cache_get_prev_sp_value (cache, tdep) - cache->framesize;
 }
 
@@ -3781,7 +3781,7 @@ arm_dwarf2_prev_register (struct frame_info *this_frame, void **this_cache,
 			  int regnum)
 {
   struct gdbarch * gdbarch = get_frame_arch (this_frame);
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   CORE_ADDR lr;
   ULONGEST cpsr;
 
@@ -4305,7 +4305,7 @@ arm_vfp_call_candidate (struct type *t, enum arm_vfp_cprc_base_type *base_type,
 static int
 arm_vfp_abi_for_function (struct gdbarch *gdbarch, struct type *func_type)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* Variadic functions always use the base ABI.  Assume that functions
      without debug info are not variadic.  */
@@ -4339,7 +4339,7 @@ arm_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
   int use_vfp_abi;
   struct type *ftype;
   unsigned vfp_regs_free = (1 << 16) - 1;
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* Determine the type of this function and whether the VFP ABI
      applies.  */
@@ -4611,7 +4611,7 @@ arm_print_float_info (struct gdbarch *gdbarch, struct ui_file *file,
 static struct type *
 arm_ext_type (struct gdbarch *gdbarch)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (!tdep->arm_ext_type)
     tdep->arm_ext_type
@@ -4624,7 +4624,7 @@ arm_ext_type (struct gdbarch *gdbarch)
 static struct type *
 arm_neon_double_type (struct gdbarch *gdbarch)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep->neon_double_type == NULL)
     {
@@ -4663,7 +4663,7 @@ arm_neon_double_type (struct gdbarch *gdbarch)
 static struct type *
 arm_neon_quad_type (struct gdbarch *gdbarch)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep->neon_quad_type == NULL)
     {
@@ -4701,7 +4701,7 @@ arm_neon_quad_type (struct gdbarch *gdbarch)
 static bool
 is_q_pseudo (struct gdbarch *gdbarch, int regnum)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* Q pseudo registers are available for both NEON (Q0~Q15) and
      MVE (Q0~Q7) features.  */
@@ -4722,7 +4722,7 @@ is_q_pseudo (struct gdbarch *gdbarch, int regnum)
 static bool
 is_s_pseudo (struct gdbarch *gdbarch, int regnum)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep->have_s_pseudos
       && regnum >= tdep->s_pseudo_base
@@ -4741,7 +4741,7 @@ is_s_pseudo (struct gdbarch *gdbarch, int regnum)
 static bool
 is_mve_pseudo (struct gdbarch *gdbarch, int regnum)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep->have_mve
       && regnum >= tdep->mve_pseudo_base
@@ -4760,7 +4760,7 @@ is_mve_pseudo (struct gdbarch *gdbarch, int regnum)
 static bool
 is_pacbti_pseudo (struct gdbarch *gdbarch, int regnum)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep->have_pacbti
       && regnum >= tdep->pacbti_pseudo_base
@@ -4776,7 +4776,7 @@ is_pacbti_pseudo (struct gdbarch *gdbarch, int regnum)
 static struct type *
 arm_register_type (struct gdbarch *gdbarch, int regnum)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (is_s_pseudo (gdbarch, regnum))
     return builtin_type (gdbarch)->builtin_float;
@@ -4855,7 +4855,7 @@ arm_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
   /* PACBTI register containing the Pointer Authentication Code.  */
   if (reg == ARM_DWARF_RA_AUTH_CODE)
     {
-      arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+      arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
       if (tdep->have_pacbti)
 	return tdep->pacbti_pseudo_base;
@@ -5001,7 +5001,7 @@ arm_adjust_breakpoint_address (struct gdbarch *gdbarch, CORE_ADDR bpaddr)
   int buf_len;
   enum bfd_endian order = gdbarch_byte_order_for_code (gdbarch);
   int i, any, last_it, last_it_count;
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* If we are using BKPT breakpoints, none of this is necessary.  */
   if (tdep->thumb2_breakpoint == NULL)
@@ -8309,7 +8309,7 @@ arm_displaced_init_closure (struct gdbarch *gdbarch, CORE_ADDR from,
 			    CORE_ADDR to,
 			    arm_displaced_step_copy_insn_closure *dsc)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   unsigned int i, len, offset;
   enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
   int size = dsc->is_thumb? 2 : 4;
@@ -8472,7 +8472,7 @@ static const gdb_byte arm_default_thumb_be_breakpoint[] = THUMB_BE_BREAKPOINT;
 static int
 arm_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
 
   if (arm_pc_is_thumb (gdbarch, *pcptr))
@@ -8507,7 +8507,7 @@ arm_breakpoint_kind_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr)
 static const gdb_byte *
 arm_sw_breakpoint_from_kind (struct gdbarch *gdbarch, int kind, int *size)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   switch (kind)
     {
@@ -8579,7 +8579,7 @@ arm_extract_return_value (struct type *type, struct regcache *regs,
 {
   struct gdbarch *gdbarch = regs->arch ();
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (TYPE_CODE_FLT == type->code ())
     {
@@ -8690,7 +8690,7 @@ arm_return_in_memory (struct gdbarch *gdbarch, struct type *type)
       return (TYPE_LENGTH (type) > 16);
     }
 
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   if (tdep->arm_abi != ARM_ABI_APCS)
     {
       /* The AAPCS says all aggregates not larger than a word are returned
@@ -8796,7 +8796,7 @@ arm_store_return_value (struct type *type, struct regcache *regs,
   if (type->code () == TYPE_CODE_FLT)
     {
       gdb_byte buf[ARM_FP_REGISTER_SIZE];
-      arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+      arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
       switch (tdep->fp_model)
 	{
@@ -8885,7 +8885,7 @@ arm_return_value (struct gdbarch *gdbarch, struct value *function,
 		  struct type *valtype, struct regcache *regcache,
 		  gdb_byte *readbuf, const gdb_byte *writebuf)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   struct type *func_type = function ? value_type (function) : NULL;
   enum arm_vfp_cprc_base_type vfp_base_type;
   int vfp_base_count;
@@ -8977,7 +8977,7 @@ static int
 arm_get_longjmp_target (struct frame_info *frame, CORE_ADDR *pc)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   CORE_ADDR jb_addr;
   gdb_byte buf[ARM_INT_REGISTER_SIZE];
@@ -9170,7 +9170,7 @@ show_fp_model (struct ui_file *file, int from_tty,
       && gdbarch_bfd_arch_info (target_gdbarch ())->arch == bfd_arch_arm)
     {
       arm_gdbarch_tdep *tdep
-	= (arm_gdbarch_tdep *) gdbarch_tdep (target_gdbarch ());
+	= gdbarch_tdep<arm_gdbarch_tdep> (target_gdbarch ());
 
       gdb_printf (file, _("\
 The current ARM floating point model is \"auto\" (currently \"%s\").\n"),
@@ -9210,7 +9210,7 @@ arm_show_abi (struct ui_file *file, int from_tty,
       && gdbarch_bfd_arch_info (target_gdbarch ())->arch == bfd_arch_arm)
     {
       arm_gdbarch_tdep *tdep
-	= (arm_gdbarch_tdep *) gdbarch_tdep (target_gdbarch ());
+	= gdbarch_tdep<arm_gdbarch_tdep> (target_gdbarch ());
 
       gdb_printf (file, _("\
 The current ARM ABI is \"auto\" (currently \"%s\").\n"),
@@ -9289,7 +9289,7 @@ show_disassembly_style_sfunc (struct ui_file *file, int from_tty,
 static const char *
 arm_register_name (struct gdbarch *gdbarch, int i)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (is_s_pseudo (gdbarch, i))
     {
@@ -9460,7 +9460,7 @@ static enum register_status
 arm_mve_pseudo_read (struct gdbarch *gdbarch, readable_regcache *regcache,
 		     int regnum, gdb_byte *buf)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* P0 is the first 16 bits of VPR.  */
   return regcache->raw_read_part (tdep->mve_vpr_regnum, 0, 2, buf);
@@ -9474,7 +9474,7 @@ arm_pseudo_read (struct gdbarch *gdbarch, readable_regcache *regcache,
   char name_buf[4];
   gdb_byte reg_buf[8];
   int offset, double_regnum;
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   gdb_assert (regnum >= num_regs);
 
@@ -9546,7 +9546,7 @@ static void
 arm_mve_pseudo_write (struct gdbarch *gdbarch, struct regcache *regcache,
 		      int regnum, const gdb_byte *buf)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   /* P0 is the first 16 bits of VPR.  */
   regcache->raw_write_part (tdep->mve_vpr_regnum, 0, 2, buf);
@@ -9560,7 +9560,7 @@ arm_pseudo_write (struct gdbarch *gdbarch, struct regcache *regcache,
   char name_buf[4];
   gdb_byte reg_buf[8];
   int offset, double_regnum;
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   gdb_assert (regnum >= num_regs);
 
@@ -9648,7 +9648,7 @@ arm_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
 static void
 arm_register_g_packet_guesses (struct gdbarch *gdbarch)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep->is_m)
     {
@@ -9691,7 +9691,7 @@ arm_register_g_packet_guesses (struct gdbarch *gdbarch)
 static int
 arm_code_of_frame_writable (struct gdbarch *gdbarch, struct frame_info *frame)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep->is_m && get_frame_type (frame) == SIGTRAMP_FRAME)
     {
@@ -10250,7 +10250,7 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
        best_arch = gdbarch_list_lookup_by_info (best_arch->next, &info))
     {
       arm_gdbarch_tdep *tdep
-	= (arm_gdbarch_tdep *) gdbarch_tdep (best_arch->gdbarch);
+	= gdbarch_tdep<arm_gdbarch_tdep> (best_arch->gdbarch);
 
       if (arm_abi != ARM_ABI_AUTO && arm_abi != tdep->arm_abi)
 	continue;
@@ -10570,7 +10570,7 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
 static void
 arm_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
 {
-  arm_gdbarch_tdep *tdep = (arm_gdbarch_tdep *) gdbarch_tdep (gdbarch);
+  arm_gdbarch_tdep *tdep = gdbarch_tdep<arm_gdbarch_tdep> (gdbarch);
 
   if (tdep == NULL)
     return;
@@ -12779,7 +12779,7 @@ arm_record_coproc_data_proc (arm_insn_decode_record *arm_insn_r)
 {
   uint32_t op, op1_ebit, coproc, bits_24_25;
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep (arm_insn_r->gdbarch);
+    = gdbarch_tdep<arm_gdbarch_tdep> (arm_insn_r->gdbarch);
   struct regcache *reg_cache = arm_insn_r->regcache;
 
   arm_insn_r->opcode = bits (arm_insn_r->arm_insn, 24, 27);
@@ -13267,7 +13267,7 @@ static int
 thumb_record_ldm_stm_swi (arm_insn_decode_record *thumb_insn_r)
 {
   arm_gdbarch_tdep *tdep
-    = (arm_gdbarch_tdep *) gdbarch_tdep  (thumb_insn_r->gdbarch);
+    = gdbarch_tdep<arm_gdbarch_tdep>  (thumb_insn_r->gdbarch);
   struct regcache *reg_cache = thumb_insn_r->regcache;
 
   uint32_t ret = 0; /* function return value: -1:record failure ;  0:success  */