Change management of tdesc_arch_data

While working on something else, I noticed that tdesc_data_cleanup
took a void* parameter.  Looking more into this, I found that
tdesc_use_registers expected a transfer of ownership.

I think it's better to express this sort of thing via the type system,
when possible.  This patch changes tdesc_data_alloc to return a unique
pointer, changes tdesc_use_registers to accept an rvalue reference,
and then adapts all the users.

Note that a deleter structure is introduced to avoid having to move
tdesc_arch_data to the header file.

2020-09-17  Tom Tromey  <tromey@adacore.com>

	* tic6x-tdep.c (tic6x_gdbarch_init): Update.
	* target-descriptions.h (struct tdesc_arch_data_deleter): New.
	(tdesc_arch_data_up): New typedef.
	(tdesc_use_registers, tdesc_data_alloc): Update.
	(tdesc_data_cleanup): Don't declare.
	* target-descriptions.c (tdesc_data_alloc): Return a
	tdesc_arch_data_up.
	(tdesc_arch_data_deleter::operator()): Rename from
	tdesc_data_cleanup.  Change argument type.
	(tdesc_use_registers): Change early_data to an rvalue reference.
	(tdesc_use_registers): Don't use delete.
	* sparc-tdep.c (sparc32_gdbarch_init): Update.
	* s390-tdep.c (s390_gdbarch_init): Update.
	* rx-tdep.c (rx_gdbarch_init): Update.
	* rs6000-tdep.c (rs6000_gdbarch_init): Update.
	* riscv-tdep.c (riscv_gdbarch_init): Update.
	* or1k-tdep.c (or1k_gdbarch_init): Update.
	* nios2-tdep.c (nios2_gdbarch_init): Update.
	* nds32-tdep.c (nds32_gdbarch_init): Update.
	* mips-tdep.c (mips_gdbarch_init): Update.
	* microblaze-tdep.c (microblaze_gdbarch_init): Update.
	* m68k-tdep.c (m68k_gdbarch_init): Update.
	* i386-tdep.c (i386_gdbarch_init): Update.
	* arm-tdep.c (arm_gdbarch_init): Update.
	* arc-tdep.c (arc_tdesc_init): Update.
	(arc_gdbarch_init): Update.
	* aarch64-tdep.c (aarch64_gdbarch_init): Update.

1 files changed, 14 insertions, 8 deletions

diff --git a/gdb/target-descriptions.h b/gdb/target-descriptions.h
index 66a2c21..171ef76 100644
--- a/gdb/target-descriptions.h
+++ b/gdb/target-descriptions.h
@@ -104,6 +104,18 @@ typedef int (*tdesc_unknown_register_ftype)
 	(struct gdbarch *gdbarch, tdesc_feature *feature,
 	 const char *reg_name, int possible_regnum);
 
+/* A deleter adapter for a target arch data.  */
+
+struct tdesc_arch_data_deleter
+{
+  void operator() (struct tdesc_arch_data *data) const;
+};
+
+/* A unique pointer specialization that holds a target_desc.  */
+
+typedef std::unique_ptr<tdesc_arch_data, tdesc_arch_data_deleter>
+  tdesc_arch_data_up;
+
 /* Update GDBARCH to use the TARGET_DESC for registers.  TARGET_DESC
    may be GDBARCH's target description or (if GDBARCH does not have
    one which describes registers) another target description
@@ -119,19 +131,13 @@ typedef int (*tdesc_unknown_register_ftype)
 
 void tdesc_use_registers (struct gdbarch *gdbarch,
 			  const struct target_desc *target_desc,
-			  struct tdesc_arch_data *early_data,
+			  tdesc_arch_data_up &&early_data,
 			  tdesc_unknown_register_ftype unk_reg_cb = NULL);
 
 /* Allocate initial data for validation of a target description during
    gdbarch initialization.  */
 
-struct tdesc_arch_data *tdesc_data_alloc (void);
-
-/* Clean up data allocated by tdesc_data_alloc.  This should only
-   be called to discard the data; tdesc_use_registers takes ownership
-   of its EARLY_DATA argument.  */
-
-void tdesc_data_cleanup (void *data_untyped);
+tdesc_arch_data_up tdesc_data_alloc ();
 
 /* Search FEATURE for a register named NAME.  Record REGNO and the
    register in DATA; when tdesc_use_registers is called, REGNO will be