Create a displaced_step_closure class hierarchy

displaced_step_closure is a type defined in multiple -tdep.c files.
Trying to xfree it from the common code (infrun.c) is a problem when we
try to poison xfree for non-POD types.  Because there can be multiple of
these types in the same build, this patch makes a hierarchy of classes
with a virtual destructor.  When the common code deletes the object
through a displaced_step_closure pointer, it will invoke the right
destructor.

The amd64 used a last-member array with a variable size.  That doesn't
work with new, so I changed it for an std::vector.  Other architectures
which used a simple byte buffer as a closure now use a shared
buf_displaced_step_closure, a closure type that only contains a
gdb::byte_vector.

Reg-tested on the buildbot.

gdb/ChangeLog:

	* infrun.h: Include common/byte-vector.h.
	(struct displaced_step_closure): New struct.
	(struct buf_displaced_step_closure): New struct.
	* infrun.c (displaced_step_closure::~displaced_step_closure):
	Provide default implementation.
	(displaced_step_clear): Deallocate step closure with delete.
	* aarch64-tdep.c (displaced_step_closure): Rename to ...
	(aarch64_displaced_step_closure): ... this, extend
	displaced_step_closure.
	(aarch64_displaced_step_data) <dsc>: Change type to
	aarch64_displaced_step_closure.
	(aarch64_displaced_step_copy_insn): Adjust to type change, use
	unique_ptr.
	(aarch64_displaced_step_fixup): Add cast for displaced step
	closure.
	* amd64-tdep.c (displaced_step_closure): Rename to ...
	(amd64_displaced_step_closure): ... this, extend
	displaced_step_closure.
	<insn_buf>: Change type to std::vector<gdb_byte>.
	<max_len>: Remove.
	(fixup_riprel): Change type of DSC parameter, adjust to type
	change of insn_buf.
	(fixup_displaced_copy): Change type of DSC parameter.
	(amd64_displaced_step_copy_insn): Instantiate
	amd64_displaced_step_closure.
	(amd64_displaced_step_fixup): Add cast for closure type, adjust
	to type change of insn_buf.
	* arm-linux-tdep.c (arm_linux_cleanup_svc): Change type of
	parameter DSC.
	(arm_linux_copy_svc): Likewise.
	(cleanup_kernel_helper_return): Likewise.
	(arm_catch_kernel_helper_return): Likewise.
	(arm_linux_displaced_step_copy_insn): Instantiate
	arm_displaced_step_closure.
	* arm-tdep.c (arm_pc_is_thumb): Add cast for closure.
	(displaced_read_reg): Change type of parameter DSC.
	(branch_write_pc): Likewise.
	(load_write_pc): Likewise.
	(alu_write_pc): Likewise.
	(displaced_write_reg): Likewise.
	(arm_copy_unmodified): Likewise.
	(thumb_copy_unmodified_32bit): Likewise.
	(thumb_copy_unmodified_16bit): Likewise.
	(cleanup_preload): Likewise.
	(install_preload): Likewise.
	(arm_copy_preload): Likewise.
	(thumb2_copy_preload): Likewise.
	(install_preload_reg): Likewise.
	(arm_copy_preload_reg): Likewise.
	(cleanup_copro_load_store): Likewise.
	(install_copro_load_store): Likewise.
	(arm_copy_copro_load_store) Likewise.
	(thumb2_copy_copro_load_store): Likewise.
	(cleanup_branch): Likewise.
	(install_b_bl_blx): Likewise.
	(arm_copy_b_bl_blx): Likewise.
	(thumb2_copy_b_bl_blx): Likewise.
	(thumb_copy_b): Likewise.
	(install_bx_blx_reg): Likewise.
	(arm_copy_bx_blx_reg): Likewise.
	(thumb_copy_bx_blx_reg): Likewise.
	(cleanup_alu_imm): Likewise.
	(arm_copy_alu_imm): Likewise.
	(thumb2_copy_alu_imm): Likewise.
	(cleanup_alu_reg): Likewise.
	(install_alu_reg): Likewise.
	(arm_copy_alu_reg): Likewise.
	(thumb_copy_alu_reg): Likewise.
	(cleanup_alu_shifted_reg): Likewise.
	(install_alu_shifted_reg): Likewise.
	(arm_copy_alu_shifted_reg): Likewise.
	(cleanup_load): Likewise.
	(cleanup_store): Likewise.
	(arm_copy_extra_ld_st): Likewise.
	(install_load_store): Likewise.
	(thumb2_copy_load_literal): Likewise.
	(thumb2_copy_load_reg_imm): Likewise.
	(arm_copy_ldr_str_ldrb_strb): Likewise.
	(cleanup_block_load_all): Likewise.
	(cleanup_block_store_pc): Likewise.
	(cleanup_block_load_pc): Likewise.
	(arm_copy_block_xfer): Likewise.
	(thumb2_copy_block_xfer): Likewise.
	(cleanup_svc): Likewise.
	(install_svc): Likewise.
	(arm_copy_svc): Likewise.
	(thumb_copy_svc): Likewise.
	(arm_copy_undef): Likewise.
	(thumb_32bit_copy_undef): Likewise.
	(arm_copy_unpred): Likewise.
	(arm_decode_misc_memhint_neon): Likewise.
	(arm_decode_unconditional): Likewise.
	(arm_decode_miscellaneous): Likewise.
	(arm_decode_dp_misc): Likewise.
	(arm_decode_ld_st_word_ubyte): Likewise.
	(arm_decode_media): Likewise.
	(arm_decode_b_bl_ldmstm): Likewise.
	(arm_decode_ext_reg_ld_st): Likewise.
	(thumb2_decode_dp_shift_reg): Likewise.
	(thumb2_decode_ext_reg_ld_st): Likewise.
	(arm_decode_svc_copro): Likewise.
	(thumb2_decode_svc_copro): Likewise.
	(install_pc_relative): Likewise.
	(thumb_copy_pc_relative_16bit): Likewise.
	(thumb_decode_pc_relative_16bit): Likewise.
	(thumb_copy_pc_relative_32bit): Likewise.
	(thumb_copy_16bit_ldr_literal): Likewise.
	(thumb_copy_cbnz_cbz): Likewise.
	(thumb2_copy_table_branch): Likewise.
	(cleanup_pop_pc_16bit_all): Likewise.
	(thumb_copy_pop_pc_16bit): Likewise.
	(thumb_process_displaced_16bit_insn): Likewise.
	(decode_thumb_32bit_ld_mem_hints): Likewise.
	(thumb_process_displaced_32bit_insn): Likewise.
	(thumb_process_displaced_insn): Likewise.
	(arm_process_displaced_insn): Likewise.
	(arm_displaced_init_closure): Likewise.
	(arm_displaced_step_fixup): Add cast for closure.
	* arm-tdep.h: Include infrun.h.
	(displaced_step_closure): Rename to ...
	(arm_displaced_step_closure): ... this, extend
	displaced_step_closure.
	<u::svc::copy_svc_os>: Change type of parameter DSC.
	<cleanup>: Likewise.
	(arm_process_displaced_insn): Likewise.
	(arm_displaced_init_closure): Likewise.
	(displaced_read_reg): Likewise.
	(displaced_write_reg): Likewise.
	* i386-linux-tdep.c (i386_linux_displaced_step_copy_insn):
	Adjust.
	* i386-tdep.h: Include infrun.h.
	(i386_displaced_step_closure): New typedef.
	* i386-tdep.c (i386_displaced_step_copy_insn): Use
	i386_displaced_step_closure.
	(i386_displaced_step_fixup): Adjust.
	* rs6000-tdep.c (ppc_displaced_step_closure): New typedef.
	(ppc_displaced_step_copy_insn): Use ppc_displaced_step_closure
	and unique_ptr.
	(ppc_displaced_step_fixup): Adjust.
	* s390-linux-tdep.c (s390_displaced_step_closure): New typedef.
	(s390_displaced_step_copy_insn): Use s390_displaced_step_closure
	and unique_ptr.
	(s390_displaced_step_fixup): Adjust.

1 files changed, 11 insertions, 10 deletions

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index a40dc69b92d..cbab1a50eeb 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -2488,14 +2488,14 @@ aarch64_software_single_step (struct regcache *regcache)
   return next_pcs;
 }
 
-struct displaced_step_closure
+struct aarch64_displaced_step_closure : public displaced_step_closure
 {
   /* It is true when condition instruction, such as B.CON, TBZ, etc,
      is being displaced stepping.  */
-  int cond;
+  int cond = 0;
 
   /* PC adjustment offset after displaced stepping.  */
-  int32_t pc_adjust;
+  int32_t pc_adjust = 0;
 };
 
 /* Data when visiting instructions for displaced stepping.  */
@@ -2513,7 +2513,7 @@ struct aarch64_displaced_step_data
   /* Registers when doing displaced stepping.  */
   struct regcache *regs;
 
-  struct displaced_step_closure *dsc;
+  aarch64_displaced_step_closure *dsc;
 };
 
 /* Implementation of aarch64_insn_visitor method "b".  */
@@ -2727,7 +2727,6 @@ aarch64_displaced_step_copy_insn (struct gdbarch *gdbarch,
 				  CORE_ADDR from, CORE_ADDR to,
 				  struct regcache *regs)
 {
-  struct displaced_step_closure *dsc = NULL;
   enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
   uint32_t insn = read_memory_unsigned_integer (from, 4, byte_order_for_code);
   struct aarch64_displaced_step_data dsd;
@@ -2743,11 +2742,12 @@ aarch64_displaced_step_copy_insn (struct gdbarch *gdbarch,
       return NULL;
     }
 
-  dsc = XCNEW (struct displaced_step_closure);
+  std::unique_ptr<aarch64_displaced_step_closure> dsc
+    (new aarch64_displaced_step_closure);
   dsd.base.insn_addr = from;
   dsd.new_addr = to;
   dsd.regs = regs;
-  dsd.dsc = dsc;
+  dsd.dsc = dsc.get ();
   dsd.insn_count = 0;
   aarch64_relocate_instruction (insn, &visitor,
 				(struct aarch64_insn_data *) &dsd);
@@ -2773,21 +2773,22 @@ aarch64_displaced_step_copy_insn (struct gdbarch *gdbarch,
     }
   else
     {
-      xfree (dsc);
       dsc = NULL;
     }
 
-  return dsc;
+  return dsc.release ();
 }
 
 /* Implement the "displaced_step_fixup" gdbarch method.  */
 
 void
 aarch64_displaced_step_fixup (struct gdbarch *gdbarch,
-			      struct displaced_step_closure *dsc,
+			      struct displaced_step_closure *dsc_,
 			      CORE_ADDR from, CORE_ADDR to,
 			      struct regcache *regs)
 {
+  aarch64_displaced_step_closure *dsc = (aarch64_displaced_step_closure *) dsc_;
+
   if (dsc->cond)
     {
       ULONGEST pc;