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, 18 insertions, 20 deletions

diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
index e56c388..08a9cae 100644
--- a/gdb/amd64-tdep.c
+++ b/gdb/amd64-tdep.c
@@ -46,6 +46,7 @@
 #include "producer.h"
 #include "ax.h"
 #include "ax-gdb.h"
+#include "common/byte-vector.h"
 
 /* Note that the AMD64 architecture was previously known as x86-64.
    The latter is (forever) engraved into the canonical system name as
@@ -1047,22 +1048,22 @@ struct amd64_insn
   gdb_byte *raw_insn;
 };
 
-struct displaced_step_closure
+struct amd64_displaced_step_closure : public displaced_step_closure
 {
+  amd64_displaced_step_closure (int insn_buf_len)
+  : insn_buf (insn_buf_len, 0)
+  {}
+
   /* For rip-relative insns, saved copy of the reg we use instead of %rip.  */
-  int tmp_used;
+  int tmp_used = 0;
   int tmp_regno;
   ULONGEST tmp_save;
 
   /* Details of the instruction.  */
   struct amd64_insn insn_details;
 
-  /* Amount of space allocated to insn_buf.  */
-  int max_len;
-
-  /* The possibly modified insn.
-     This is a variable-length field.  */
-  gdb_byte insn_buf[1];
+  /* The possibly modified insn.  */
+  gdb::byte_vector insn_buf;
 };
 
 /* WARNING: Keep onebyte_has_modrm, twobyte_has_modrm in sync with
@@ -1303,7 +1304,7 @@ amd64_get_insn_details (gdb_byte *insn, struct amd64_insn *details)
    We set base = pc + insn_length so we can leave disp unchanged.  */
 
 static void
-fixup_riprel (struct gdbarch *gdbarch, struct displaced_step_closure *dsc,
+fixup_riprel (struct gdbarch *gdbarch, amd64_displaced_step_closure *dsc,
 	      CORE_ADDR from, CORE_ADDR to, struct regcache *regs)
 {
   const struct amd64_insn *insn_details = &dsc->insn_details;
@@ -1318,8 +1319,8 @@ fixup_riprel (struct gdbarch *gdbarch, struct displaced_step_closure *dsc,
   ++insn;
 
   /* Compute the rip-relative address.	*/
-  insn_length = gdb_buffered_insn_length (gdbarch, dsc->insn_buf,
-					  dsc->max_len, from);
+  insn_length = gdb_buffered_insn_length (gdbarch, dsc->insn_buf.data (),
+					  dsc->insn_buf.size (), from);
   rip_base = from + insn_length;
 
   /* We need a register to hold the address.
@@ -1353,7 +1354,7 @@ fixup_riprel (struct gdbarch *gdbarch, struct displaced_step_closure *dsc,
 
 static void
 fixup_displaced_copy (struct gdbarch *gdbarch,
-		      struct displaced_step_closure *dsc,
+		      amd64_displaced_step_closure *dsc,
 		      CORE_ADDR from, CORE_ADDR to, struct regcache *regs)
 {
   const struct amd64_insn *details = &dsc->insn_details;
@@ -1380,15 +1381,11 @@ amd64_displaced_step_copy_insn (struct gdbarch *gdbarch,
   /* Extra space for sentinels so fixup_{riprel,displaced_copy} don't have to
      continually watch for running off the end of the buffer.  */
   int fixup_sentinel_space = len;
-  struct displaced_step_closure *dsc
-    = ((struct displaced_step_closure *)
-       xmalloc (sizeof (*dsc) + len + fixup_sentinel_space));
+  amd64_displaced_step_closure *dsc
+    = new amd64_displaced_step_closure (len + fixup_sentinel_space);
   gdb_byte *buf = &dsc->insn_buf[0];
   struct amd64_insn *details = &dsc->insn_details;
 
-  dsc->tmp_used = 0;
-  dsc->max_len = len + fixup_sentinel_space;
-
   read_memory (from, buf, len);
 
   /* Set up the sentinel space so we don't have to worry about running
@@ -1583,14 +1580,15 @@ amd64_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr)
 
 void
 amd64_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)
 {
+  amd64_displaced_step_closure *dsc = (amd64_displaced_step_closure *) dsc_;
   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
   /* The offset we applied to the instruction's address.  */
   ULONGEST insn_offset = to - from;
-  gdb_byte *insn = dsc->insn_buf;
+  gdb_byte *insn = dsc->insn_buf.data ();
   const struct amd64_insn *insn_details = &dsc->insn_details;
 
   if (debug_displaced)