Support displaced stepping in aarch64-linux

This patch is to support displaced stepping in aarch64-linux.  A
visitor is implemented for displaced stepping, and used to record
information to fixup pc after displaced stepping if needed.  Some
emit_* functions are converted to macros, and moved to
arch/aarch64-insn.{c,h} so that they can be shared.

gdb:

2015-10-12  Yao Qi  <yao.qi@linaro.org>

	* aarch64-linux-tdep.c: Include arch-utils.h.
	(aarch64_linux_init_abi): Call set_gdbarch_max_insn_length,
	set_gdbarch_displaced_step_copy_insn,
	set_gdbarch_displaced_step_fixup,
	set_gdbarch_displaced_step_free_closure,
	set_gdbarch_displaced_step_location,
	and set_gdbarch_displaced_step_hw_singlestep.
	* aarch64-tdep.c (struct displaced_step_closure): New.
	(struct aarch64_displaced_step_data): New.
	(aarch64_displaced_step_b): New function.
	(aarch64_displaced_step_b_cond): Likewise.
	(aarch64_register): Likewise.
	(aarch64_displaced_step_cb): Likewise.
	(aarch64_displaced_step_tb): Likewise.
	(aarch64_displaced_step_adr): Likewise.
	(aarch64_displaced_step_ldr_literal): Likewise.
	(aarch64_displaced_step_others): Likewise.
	(aarch64_displaced_step_copy_insn): Likewise.
	(aarch64_displaced_step_fixup): Likewise.
	(aarch64_displaced_step_hw_singlestep): Likewise.
	* aarch64-tdep.h (DISPLACED_MODIFIED_INSNS): New macro.
	(aarch64_displaced_step_copy_insn): Declare.
	(aarch64_displaced_step_fixup): Declare.
	(aarch64_displaced_step_hw_singlestep): Declare.
	* arch/aarch64-insn.c (emit_insn): Moved from
	gdbserver/linux-aarch64-low.c.
	(emit_load_store): Likewise.
	* arch/aarch64-insn.h (enum aarch64_opcodes): Moved from
	gdbserver/linux-aarch64-low.c.
	(struct aarch64_register): Likewise.
	(struct aarch64_memory_operand): Likewise.
	(ENCODE): Likewise.
	(can_encode_int32): New macro.
	(emit_b, emit_bcond, emit_cb, emit_ldr, emit_ldrsw): Likewise.
	(emit_tb, emit_nop): Likewise.
	(emit_insn): Declare.
	(emit_load_store): Declare.

gdb/gdbserver:

2015-10-12  Yao Qi  <yao.qi@linaro.org>

	* linux-aarch64-low.c (enum aarch64_opcodes): Move to
	arch/aarch64-insn.h.
	(struct aarch64_memory_operand): Likewise.
	(ENCODE): Likewise.
	(emit_insn): Move to arch/aarch64-insn.c.
	(emit_b, emit_bcond, emit_cb, emit_tb): Remove.
	(emit_load_store): Move to arch/aarch64-insn.c.
	(emit_ldr, emit_ldrb, emit_ldrsw, emit_nop): Remove.
	(can_encode_int32): Remove.

8 files changed, 711 insertions, 320 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f79c93d..45a85e5 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,45 @@
 2015-10-12  Yao Qi  <yao.qi@linaro.org>
 
+	* aarch64-linux-tdep.c: Include arch-utils.h.
+	(aarch64_linux_init_abi): Call set_gdbarch_max_insn_length,
+	set_gdbarch_displaced_step_copy_insn,
+	set_gdbarch_displaced_step_fixup,
+	set_gdbarch_displaced_step_free_closure,
+	set_gdbarch_displaced_step_location,
+	and set_gdbarch_displaced_step_hw_singlestep.
+	* aarch64-tdep.c (struct displaced_step_closure): New.
+	(struct aarch64_displaced_step_data): New.
+	(aarch64_displaced_step_b): New function.
+	(aarch64_displaced_step_b_cond): Likewise.
+	(aarch64_register): Likewise.
+	(aarch64_displaced_step_cb): Likewise.
+	(aarch64_displaced_step_tb): Likewise.
+	(aarch64_displaced_step_adr): Likewise.
+	(aarch64_displaced_step_ldr_literal): Likewise.
+	(aarch64_displaced_step_others): Likewise.
+	(aarch64_displaced_step_copy_insn): Likewise.
+	(aarch64_displaced_step_fixup): Likewise.
+	(aarch64_displaced_step_hw_singlestep): Likewise.
+	* aarch64-tdep.h (DISPLACED_MODIFIED_INSNS): New macro.
+	(aarch64_displaced_step_copy_insn): Declare.
+	(aarch64_displaced_step_fixup): Declare.
+	(aarch64_displaced_step_hw_singlestep): Declare.
+	* arch/aarch64-insn.c (emit_insn): Moved from
+	gdbserver/linux-aarch64-low.c.
+	(emit_load_store): Likewise.
+	* arch/aarch64-insn.h (enum aarch64_opcodes): Moved from
+	gdbserver/linux-aarch64-low.c.
+	(struct aarch64_register): Likewise.
+	(struct aarch64_memory_operand): Likewise.
+	(ENCODE): Likewise.
+	(can_encode_int32): New macro.
+	(emit_b, emit_bcond, emit_cb, emit_ldr, emit_ldrsw): Likewise.
+	(emit_tb, emit_nop): Likewise.
+	(emit_insn): Declare.
+	(emit_load_store): Declare.
+
+2015-10-12  Yao Qi  <yao.qi@linaro.org>
+
 	* arch/aarch64-insn.c (aarch64_decode_ldr_literal): Moved from
 	gdbserver/linux-aarch64-low.c.
 	(aarch64_relocate_instruction): Likewise.
diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index aaf6608..272aafe 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -21,6 +21,7 @@
 #include "defs.h"
 
 #include "gdbarch.h"
+#include "arch-utils.h"
 #include "glibc-tdep.h"
 #include "linux-tdep.h"
 #include "aarch64-tdep.h"
@@ -1151,6 +1152,17 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   /* `catch syscall' */
   set_xml_syscall_file_name (gdbarch, "syscalls/aarch64-linux.xml");
   set_gdbarch_get_syscall_number (gdbarch, aarch64_linux_get_syscall_number);
+
+  /* Displaced stepping.  */
+  set_gdbarch_max_insn_length (gdbarch, 4 * DISPLACED_MODIFIED_INSNS);
+  set_gdbarch_displaced_step_copy_insn (gdbarch,
+					aarch64_displaced_step_copy_insn);
+  set_gdbarch_displaced_step_fixup (gdbarch, aarch64_displaced_step_fixup);
+  set_gdbarch_displaced_step_free_closure (gdbarch,
+					   simple_displaced_step_free_closure);
+  set_gdbarch_displaced_step_location (gdbarch, linux_displaced_step_location);
+  set_gdbarch_displaced_step_hw_singlestep (gdbarch,
+					    aarch64_displaced_step_hw_singlestep);
 }
 
 /* Provide a prototype to silence -Wmissing-prototypes.  */
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 90ee204..8426063 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -2559,6 +2559,343 @@ aarch64_software_single_step (struct frame_info *frame)
   return 1;
 }
 
+struct displaced_step_closure
+{
+  /* It is true when condition instruction, such as B.CON, TBZ, etc,
+     is being displaced stepping.  */
+  int cond;
+
+  /* PC adjustment offset after displaced stepping.  */
+  int32_t pc_adjust;
+};
+
+/* Data when visiting instructions for displaced stepping.  */
+
+struct aarch64_displaced_step_data
+{
+  struct aarch64_insn_data base;
+
+  /* The address where the instruction will be executed at.  */
+  CORE_ADDR new_addr;
+  /* Buffer of instructions to be copied to NEW_ADDR to execute.  */
+  uint32_t insn_buf[DISPLACED_MODIFIED_INSNS];
+  /* Number of instructions in INSN_BUF.  */
+  unsigned insn_count;
+  /* Registers when doing displaced stepping.  */
+  struct regcache *regs;
+
+  struct displaced_step_closure *dsc;
+};
+
+/* Implementation of aarch64_insn_visitor method "b".  */
+
+static void
+aarch64_displaced_step_b (const int is_bl, const int32_t offset,
+			  struct aarch64_insn_data *data)
+{
+  struct aarch64_displaced_step_data *dsd
+    = (struct aarch64_displaced_step_data *) data;
+  int32_t new_offset = data->insn_addr - dsd->new_addr + offset;
+
+  if (can_encode_int32 (new_offset, 28))
+    {
+      /* Emit B rather than BL, because executing BL on a new address
+	 will get the wrong address into LR.  In order to avoid this,
+	 we emit B, and update LR if the instruction is BL.  */
+      emit_b (dsd->insn_buf, 0, new_offset);
+      dsd->insn_count++;
+    }
+  else
+    {
+      /* Write NOP.  */
+      emit_nop (dsd->insn_buf);
+      dsd->insn_count++;
+      dsd->dsc->pc_adjust = offset;
+    }
+
+  if (is_bl)
+    {
+      /* Update LR.  */
+      regcache_cooked_write_unsigned (dsd->regs, AARCH64_LR_REGNUM,
+				      data->insn_addr + 4);
+    }
+}
+
+/* Implementation of aarch64_insn_visitor method "b_cond".  */
+
+static void
+aarch64_displaced_step_b_cond (const unsigned cond, const int32_t offset,
+			       struct aarch64_insn_data *data)
+{
+  struct aarch64_displaced_step_data *dsd
+    = (struct aarch64_displaced_step_data *) data;
+  int32_t new_offset = data->insn_addr - dsd->new_addr + offset;
+
+  /* GDB has to fix up PC after displaced step this instruction
+     differently according to the condition is true or false.  Instead
+     of checking COND against conditional flags, we can use
+     the following instructions, and GDB can tell how to fix up PC
+     according to the PC value.
+
+     B.COND TAKEN    ; If cond is true, then jump to TAKEN.
+     INSN1     ;
+     TAKEN:
+     INSN2
+  */
+
+  emit_bcond (dsd->insn_buf, cond, 8);
+  dsd->dsc->cond = 1;
+  dsd->dsc->pc_adjust = offset;
+  dsd->insn_count = 1;
+}
+
+/* Dynamically allocate a new register.  If we know the register
+   statically, we should make it a global as above instead of using this
+   helper function.  */
+
+static struct aarch64_register
+aarch64_register (unsigned num, int is64)
+{
+  return (struct aarch64_register) { num, is64 };
+}
+
+/* Implementation of aarch64_insn_visitor method "cb".  */
+
+static void
+aarch64_displaced_step_cb (const int32_t offset, const int is_cbnz,
+			   const unsigned rn, int is64,
+			   struct aarch64_insn_data *data)
+{
+  struct aarch64_displaced_step_data *dsd
+    = (struct aarch64_displaced_step_data *) data;
+  int32_t new_offset = data->insn_addr - dsd->new_addr + offset;
+
+  /* The offset is out of range for a compare and branch
+     instruction.  We can use the following instructions instead:
+
+	 CBZ xn, TAKEN   ; xn == 0, then jump to TAKEN.
+	 INSN1     ;
+	 TAKEN:
+	 INSN2
+  */
+  emit_cb (dsd->insn_buf, is_cbnz, aarch64_register (rn, is64), 8);
+  dsd->insn_count = 1;
+  dsd->dsc->cond = 1;
+  dsd->dsc->pc_adjust = offset;
+}
+
+/* Implementation of aarch64_insn_visitor method "tb".  */
+
+static void
+aarch64_displaced_step_tb (const int32_t offset, int is_tbnz,
+			   const unsigned rt, unsigned bit,
+			   struct aarch64_insn_data *data)
+{
+  struct aarch64_displaced_step_data *dsd
+    = (struct aarch64_displaced_step_data *) data;
+  int32_t new_offset = data->insn_addr - dsd->new_addr + offset;
+
+  /* The offset is out of range for a test bit and branch
+     instruction We can use the following instructions instead:
+
+     TBZ xn, #bit, TAKEN ; xn[bit] == 0, then jump to TAKEN.
+     INSN1         ;
+     TAKEN:
+     INSN2
+
+  */
+  emit_tb (dsd->insn_buf, is_tbnz, bit, aarch64_register (rt, 1), 8);
+  dsd->insn_count = 1;
+  dsd->dsc->cond = 1;
+  dsd->dsc->pc_adjust = offset;
+}
+
+/* Implementation of aarch64_insn_visitor method "adr".  */
+
+static void
+aarch64_displaced_step_adr (const int32_t offset, const unsigned rd,
+			    const int is_adrp, struct aarch64_insn_data *data)
+{
+  struct aarch64_displaced_step_data *dsd
+    = (struct aarch64_displaced_step_data *) data;
+  /* We know exactly the address the ADR{P,} instruction will compute.
+     We can just write it to the destination register.  */
+  CORE_ADDR address = data->insn_addr + offset;
+
+  if (is_adrp)
+    {
+      /* Clear the lower 12 bits of the offset to get the 4K page.  */
+      regcache_cooked_write_unsigned (dsd->regs, AARCH64_X0_REGNUM + rd,
+				      address & ~0xfff);
+    }
+  else
+      regcache_cooked_write_unsigned (dsd->regs, AARCH64_X0_REGNUM + rd,
+				      address);
+
+  dsd->dsc->pc_adjust = 4;
+  emit_nop (dsd->insn_buf);
+  dsd->insn_count = 1;
+}
+
+/* Implementation of aarch64_insn_visitor method "ldr_literal".  */
+
+static void
+aarch64_displaced_step_ldr_literal (const int32_t offset, const int is_sw,
+				    const unsigned rt, const int is64,
+				    struct aarch64_insn_data *data)
+{
+  struct aarch64_displaced_step_data *dsd
+    = (struct aarch64_displaced_step_data *) data;
+  CORE_ADDR address = data->insn_addr + offset;
+  struct aarch64_memory_operand zero = { MEMORY_OPERAND_OFFSET, 0 };
+
+  regcache_cooked_write_unsigned (dsd->regs, AARCH64_X0_REGNUM + rt,
+				  address);
+
+  if (is_sw)
+    dsd->insn_count = emit_ldrsw (dsd->insn_buf, aarch64_register (rt, 1),
+				  aarch64_register (rt, 1), zero);
+  else
+    dsd->insn_count = emit_ldr (dsd->insn_buf, aarch64_register (rt, is64),
+				aarch64_register (rt, 1), zero);
+
+  dsd->dsc->pc_adjust = 4;
+}
+
+/* Implementation of aarch64_insn_visitor method "others".  */
+
+static void
+aarch64_displaced_step_others (const uint32_t insn,
+			       struct aarch64_insn_data *data)
+{
+  struct aarch64_displaced_step_data *dsd
+    = (struct aarch64_displaced_step_data *) data;
+
+  emit_insn (dsd->insn_buf, insn);
+  dsd->insn_count = 1;
+
+  if ((insn & 0xfffffc1f) == 0xd65f0000)
+    {
+      /* RET */
+      dsd->dsc->pc_adjust = 0;
+    }
+  else
+    dsd->dsc->pc_adjust = 4;
+}
+
+static const struct aarch64_insn_visitor visitor =
+{
+  aarch64_displaced_step_b,
+  aarch64_displaced_step_b_cond,
+  aarch64_displaced_step_cb,
+  aarch64_displaced_step_tb,
+  aarch64_displaced_step_adr,
+  aarch64_displaced_step_ldr_literal,
+  aarch64_displaced_step_others,
+};
+
+/* Implement the "displaced_step_copy_insn" gdbarch method.  */
+
+struct displaced_step_closure *
+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;
+
+  /* Look for a Load Exclusive instruction which begins the sequence.  */
+  if (decode_masked_match (insn, 0x3fc00000, 0x08400000))
+    {
+      /* We can't displaced step atomic sequences.  */
+      return NULL;
+    }
+
+  dsc = XCNEW (struct displaced_step_closure);
+  dsd.base.insn_addr = from;
+  dsd.new_addr = to;
+  dsd.regs = regs;
+  dsd.dsc = dsc;
+  aarch64_relocate_instruction (insn, &visitor,
+				(struct aarch64_insn_data *) &dsd);
+  gdb_assert (dsd.insn_count <= DISPLACED_MODIFIED_INSNS);
+
+  if (dsd.insn_count != 0)
+    {
+      int i;
+
+      /* Instruction can be relocated to scratch pad.  Copy
+	 relocated instruction(s) there.  */
+      for (i = 0; i < dsd.insn_count; i++)
+	{
+	  if (debug_displaced)
+	    {
+	      debug_printf ("displaced: writing insn ");
+	      debug_printf ("%.8x", dsd.insn_buf[i]);
+	      debug_printf (" at %s\n", paddress (gdbarch, to + i * 4));
+	    }
+	  write_memory_unsigned_integer (to + i * 4, 4, byte_order_for_code,
+					 (ULONGEST) dsd.insn_buf[i]);
+	}
+    }
+  else
+    {
+      xfree (dsc);
+      dsc = NULL;
+    }
+
+  return dsc;
+}
+
+/* Implement the "displaced_step_fixup" gdbarch method.  */
+
+void
+aarch64_displaced_step_fixup (struct gdbarch *gdbarch,
+			      struct displaced_step_closure *dsc,
+			      CORE_ADDR from, CORE_ADDR to,
+			      struct regcache *regs)
+{
+  if (dsc->cond)
+    {
+      ULONGEST pc;
+
+      regcache_cooked_read_unsigned (regs, AARCH64_PC_REGNUM, &pc);
+      if (pc - to == 8)
+	{
+	  /* Condition is true.  */
+	}
+      else if (pc - to == 4)
+	{
+	  /* Condition is false.  */
+	  dsc->pc_adjust = 4;
+	}
+      else
+	gdb_assert_not_reached ("Unexpected PC value after displaced stepping");
+    }
+
+  if (dsc->pc_adjust != 0)
+    {
+      if (debug_displaced)
+	{
+	  debug_printf ("displaced: fixup: set PC to %s:%d\n",
+			paddress (gdbarch, from), dsc->pc_adjust);
+	}
+      regcache_cooked_write_unsigned (regs, AARCH64_PC_REGNUM,
+				      from + dsc->pc_adjust);
+    }
+}
+
+/* Implement the "displaced_step_hw_singlestep" gdbarch method.  */
+
+int
+aarch64_displaced_step_hw_singlestep (struct gdbarch *gdbarch,
+				      struct displaced_step_closure *closure)
+{
+  return 1;
+}
+
 /* Initialize the current architecture based on INFO.  If possible,
    re-use an architecture from ARCHES, which is a list of
    architectures already created during this debugging session.
diff --git a/gdb/aarch64-tdep.h b/gdb/aarch64-tdep.h
index af209a9..6297170 100644
--- a/gdb/aarch64-tdep.h
+++ b/gdb/aarch64-tdep.h
@@ -69,6 +69,10 @@ enum aarch64_regnum
 /* Total number of general (X) registers.  */
 #define AARCH64_X_REGISTER_COUNT 32
 
+/* The maximum number of modified instructions generated for one
+   single-stepped instruction.  */
+#define DISPLACED_MODIFIED_INSNS 1
+
 /* Target-dependent structure in gdbarch.  */
 struct gdbarch_tdep
 {
@@ -98,4 +102,17 @@ extern struct target_desc *tdesc_aarch64;
 extern int aarch64_process_record (struct gdbarch *gdbarch,
                                struct regcache *regcache, CORE_ADDR addr);
 
+struct displaced_step_closure *
+  aarch64_displaced_step_copy_insn (struct gdbarch *gdbarch,
+				    CORE_ADDR from, CORE_ADDR to,
+				    struct regcache *regs);
+
+void aarch64_displaced_step_fixup (struct gdbarch *gdbarch,
+				   struct displaced_step_closure *dsc,
+				   CORE_ADDR from, CORE_ADDR to,
+				   struct regcache *regs);
+
+int aarch64_displaced_step_hw_singlestep (struct gdbarch *gdbarch,
+					  struct displaced_step_closure *closure);
+
 #endif /* aarch64-tdep.h */
diff --git a/gdb/arch/aarch64-insn.c b/gdb/arch/aarch64-insn.c
index d0e88fa..3bc0117 100644
--- a/gdb/arch/aarch64-insn.c
+++ b/gdb/arch/aarch64-insn.c
@@ -328,3 +328,61 @@ aarch64_relocate_instruction (uint32_t insn,
   else
     visitor->others (insn, data);
 }
+
+/* Write a 32-bit unsigned integer INSN info *BUF.  Return the number of
+   instructions written (aka. 1).  */
+
+int
+emit_insn (uint32_t *buf, uint32_t insn)
+{
+  *buf = insn;
+  return 1;
+}
+
+/* Helper function emitting a load or store instruction.  */
+
+int
+emit_load_store (uint32_t *buf, uint32_t size,
+		 enum aarch64_opcodes opcode,
+		 struct aarch64_register rt,
+		 struct aarch64_register rn,
+		 struct aarch64_memory_operand operand)
+{
+  uint32_t op;
+
+  switch (operand.type)
+    {
+    case MEMORY_OPERAND_OFFSET:
+      {
+	op = ENCODE (1, 1, 24);
+
+	return emit_insn (buf, opcode | ENCODE (size, 2, 30) | op
+			  | ENCODE (operand.index >> 3, 12, 10)
+			  | ENCODE (rn.num, 5, 5)
+			  | ENCODE (rt.num, 5, 0));
+      }
+    case MEMORY_OPERAND_POSTINDEX:
+      {
+	uint32_t post_index = ENCODE (1, 2, 10);
+
+	op = ENCODE (0, 1, 24);
+
+	return emit_insn (buf, opcode | ENCODE (size, 2, 30) | op
+			  | post_index | ENCODE (operand.index, 9, 12)
+			  | ENCODE (rn.num, 5, 5) | ENCODE (rt.num, 5, 0));
+      }
+    case MEMORY_OPERAND_PREINDEX:
+      {
+	uint32_t pre_index = ENCODE (3, 2, 10);
+
+	op = ENCODE (0, 1, 24);
+
+	return emit_insn (buf, opcode | ENCODE (size, 2, 30) | op
+			  | pre_index | ENCODE (operand.index, 9, 12)
+			  | ENCODE (rn.num, 5, 5)
+			  | ENCODE (rt.num, 5, 0));
+      }
+    default:
+      return 0;
+    }
+}
diff --git a/gdb/arch/aarch64-insn.h b/gdb/arch/aarch64-insn.h
index 47f6715..01a5d73 100644
--- a/gdb/arch/aarch64-insn.h
+++ b/gdb/arch/aarch64-insn.h
@@ -21,6 +21,129 @@
 
 extern int aarch64_debug;
 
+/* List of opcodes that we need for building the jump pad and relocating
+   an instruction.  */
+
+enum aarch64_opcodes
+{
+  /* B              0001 01ii iiii iiii iiii iiii iiii iiii */
+  /* BL             1001 01ii iiii iiii iiii iiii iiii iiii */
+  /* B.COND         0101 0100 iiii iiii iiii iiii iii0 cccc */
+  /* CBZ            s011 0100 iiii iiii iiii iiii iiir rrrr */
+  /* CBNZ           s011 0101 iiii iiii iiii iiii iiir rrrr */
+  /* TBZ            b011 0110 bbbb biii iiii iiii iiir rrrr */
+  /* TBNZ           b011 0111 bbbb biii iiii iiii iiir rrrr */
+  B               = 0x14000000,
+  BL              = 0x80000000 | B,
+  BCOND           = 0x40000000 | B,
+  CBZ             = 0x20000000 | B,
+  CBNZ            = 0x21000000 | B,
+  TBZ             = 0x36000000 | B,
+  TBNZ            = 0x37000000 | B,
+  /* BLR            1101 0110 0011 1111 0000 00rr rrr0 0000 */
+  BLR             = 0xd63f0000,
+  /* RET            1101 0110 0101 1111 0000 00rr rrr0 0000 */
+  RET             = 0xd65f0000,
+  /* STP            s010 100o o0ii iiii irrr rrrr rrrr rrrr */
+  /* LDP            s010 100o o1ii iiii irrr rrrr rrrr rrrr */
+  /* STP (SIMD&VFP) ss10 110o o0ii iiii irrr rrrr rrrr rrrr */
+  /* LDP (SIMD&VFP) ss10 110o o1ii iiii irrr rrrr rrrr rrrr */
+  STP             = 0x28000000,
+  LDP             = 0x28400000,
+  STP_SIMD_VFP    = 0x04000000 | STP,
+  LDP_SIMD_VFP    = 0x04000000 | LDP,
+  /* STR            ss11 100o 00xi iiii iiii xxrr rrrr rrrr */
+  /* LDR            ss11 100o 01xi iiii iiii xxrr rrrr rrrr */
+  /* LDRSW          1011 100o 10xi iiii iiii xxrr rrrr rrrr */
+  STR             = 0x38000000,
+  LDR             = 0x00400000 | STR,
+  LDRSW           = 0x80800000 | STR,
+  /* LDAXR          ss00 1000 0101 1111 1111 11rr rrrr rrrr */
+  LDAXR           = 0x085ffc00,
+  /* STXR           ss00 1000 000r rrrr 0111 11rr rrrr rrrr */
+  STXR            = 0x08007c00,
+  /* STLR           ss00 1000 1001 1111 1111 11rr rrrr rrrr */
+  STLR            = 0x089ffc00,
+  /* MOV            s101 0010 1xxi iiii iiii iiii iiir rrrr */
+  /* MOVK           s111 0010 1xxi iiii iiii iiii iiir rrrr */
+  MOV             = 0x52800000,
+  MOVK            = 0x20000000 | MOV,
+  /* ADD            s00o ooo1 xxxx xxxx xxxx xxxx xxxx xxxx */
+  /* SUB            s10o ooo1 xxxx xxxx xxxx xxxx xxxx xxxx */
+  /* SUBS           s11o ooo1 xxxx xxxx xxxx xxxx xxxx xxxx */
+  ADD             = 0x01000000,
+  SUB             = 0x40000000 | ADD,
+  SUBS            = 0x20000000 | SUB,
+  /* AND            s000 1010 xx0x xxxx xxxx xxxx xxxx xxxx */
+  /* ORR            s010 1010 xx0x xxxx xxxx xxxx xxxx xxxx */
+  /* ORN            s010 1010 xx1x xxxx xxxx xxxx xxxx xxxx */
+  /* EOR            s100 1010 xx0x xxxx xxxx xxxx xxxx xxxx */
+  AND             = 0x0a000000,
+  ORR             = 0x20000000 | AND,
+  ORN             = 0x00200000 | ORR,
+  EOR             = 0x40000000 | AND,
+  /* LSLV           s001 1010 110r rrrr 0010 00rr rrrr rrrr */
+  /* LSRV           s001 1010 110r rrrr 0010 01rr rrrr rrrr */
+  /* ASRV           s001 1010 110r rrrr 0010 10rr rrrr rrrr */
+  LSLV             = 0x1ac02000,
+  LSRV             = 0x00000400 | LSLV,
+  ASRV             = 0x00000800 | LSLV,
+  /* SBFM           s001 0011 0nii iiii iiii iirr rrrr rrrr */
+  SBFM            = 0x13000000,
+  /* UBFM           s101 0011 0nii iiii iiii iirr rrrr rrrr */
+  UBFM            = 0x40000000 | SBFM,
+  /* CSINC          s001 1010 100r rrrr cccc 01rr rrrr rrrr */
+  CSINC           = 0x9a800400,
+  /* MUL            s001 1011 000r rrrr 0111 11rr rrrr rrrr */
+  MUL             = 0x1b007c00,
+  /* MSR (register) 1101 0101 0001 oooo oooo oooo ooor rrrr */
+  /* MRS            1101 0101 0011 oooo oooo oooo ooor rrrr */
+  MSR             = 0xd5100000,
+  MRS             = 0x00200000 | MSR,
+  /* HINT           1101 0101 0000 0011 0010 oooo ooo1 1111 */
+  HINT            = 0xd503201f,
+  SEVL            = (5 << 5) | HINT,
+  WFE             = (2 << 5) | HINT,
+  NOP             = (0 << 5) | HINT,
+};
+
+/* Representation of a general purpose register of the form xN or wN.
+
+   This type is used by emitting functions that take registers as operands.  */
+
+struct aarch64_register
+{
+  unsigned num;
+  int is64;
+};
+
+/* Representation of a memory operand, used for load and store
+   instructions.
+
+   The types correspond to the following variants:
+
+   MEMORY_OPERAND_OFFSET:    LDR rt, [rn, #offset]
+   MEMORY_OPERAND_PREINDEX:  LDR rt, [rn, #index]!
+   MEMORY_OPERAND_POSTINDEX: LDR rt, [rn], #index  */
+
+struct aarch64_memory_operand
+{
+  /* Type of the operand.  */
+  enum
+    {
+      MEMORY_OPERAND_OFFSET,
+      MEMORY_OPERAND_PREINDEX,
+      MEMORY_OPERAND_POSTINDEX,
+    } type;
+  /* Index from the base register.  */
+  int32_t index;
+};
+
+/* Helper macro to mask and shift a value into a bitfield.  */
+
+#define ENCODE(val, size, offset) \
+  ((uint32_t) ((val & ((1ULL << size) - 1)) << offset))
+
 int aarch64_decode_adr (CORE_ADDR addr, uint32_t insn, int *is_adrp,
 			unsigned *rd, int32_t *offset);
 
@@ -86,4 +209,113 @@ void aarch64_relocate_instruction (uint32_t insn,
 				   const struct aarch64_insn_visitor *visitor,
 				   struct aarch64_insn_data *data);
 
+#define can_encode_int32(val, bits)			\
+  (((val) >> (bits)) == 0 || ((val) >> (bits)) == -1)
+
+/* Write a B or BL instruction into *BUF.
+
+     B  #offset
+     BL #offset
+
+   IS_BL specifies if the link register should be updated.
+   OFFSET is the immediate offset from the current PC.  It is
+   byte-addressed but should be 4 bytes aligned.  It has a limited range of
+   +/- 128MB (26 bits << 2).  */
+
+#define emit_b(buf, is_bl, offset) \
+  emit_insn (buf, ((is_bl) ? BL : B) | (ENCODE ((offset) >> 2, 26, 0)))
+
+/* Write a BCOND instruction into *BUF.
+
+     B.COND #offset
+
+   COND specifies the condition field.
+   OFFSET is the immediate offset from the current PC.  It is
+   byte-addressed but should be 4 bytes aligned.  It has a limited range of
+   +/- 1MB (19 bits << 2).  */
+
+#define emit_bcond(buf, cond, offset)			\
+  emit_insn (buf,					\
+	     BCOND | ENCODE ((offset) >> 2, 19, 5)	\
+	     | ENCODE ((cond), 4, 0))
+
+/* Write a CBZ or CBNZ instruction into *BUF.
+
+     CBZ  rt, #offset
+     CBNZ rt, #offset
+
+   IS_CBNZ distinguishes between CBZ and CBNZ instructions.
+   RN is the register to test.
+   OFFSET is the immediate offset from the current PC.  It is
+   byte-addressed but should be 4 bytes aligned.  It has a limited range of
+   +/- 1MB (19 bits << 2).  */
+
+#define emit_cb(buf, is_cbnz, rt, offset)		\
+  emit_insn (buf,					\
+	     ((is_cbnz) ? CBNZ : CBZ)			\
+	     | ENCODE (rt.is64, 1, 31)  /* sf */	\
+	     | ENCODE (offset >> 2, 19, 5) /* imm19 */	\
+	     | ENCODE (rt.num, 5, 0))
+
+/* Write a LDR instruction into *BUF.
+
+     LDR rt, [rn, #offset]
+     LDR rt, [rn, #index]!
+     LDR rt, [rn], #index
+
+   RT is the register to store.
+   RN is the base address register.
+   OFFSET is the immediate to add to the base address.  It is limited to
+   0 .. 32760 range (12 bits << 3).  */
+
+#define emit_ldr(buf, rt, rn, operand) \
+  emit_load_store (buf, rt.is64 ? 3 : 2, LDR, rt, rn, operand)
+
+/* Write a LDRSW instruction into *BUF.  The register size is 64-bit.
+
+     LDRSW xt, [rn, #offset]
+     LDRSW xt, [rn, #index]!
+     LDRSW xt, [rn], #index
+
+   RT is the register to store.
+   RN is the base address register.
+   OFFSET is the immediate to add to the base address.  It is limited to
+   0 .. 16380 range (12 bits << 2).  */
+
+#define emit_ldrsw(buf, rt, rn, operand)		\
+  emit_load_store (buf, 3, LDRSW, rt, rn, operand)
+
+
+/* Write a TBZ or TBNZ instruction into *BUF.
+
+   TBZ  rt, #bit, #offset
+   TBNZ rt, #bit, #offset
+
+   IS_TBNZ distinguishes between TBZ and TBNZ instructions.
+   RT is the register to test.
+   BIT is the index of the bit to test in register RT.
+   OFFSET is the immediate offset from the current PC.  It is
+   byte-addressed but should be 4 bytes aligned.  It has a limited range of
+   +/- 32KB (14 bits << 2).  */
+
+#define emit_tb(buf, is_tbnz, bit, rt, offset)	       \
+  emit_insn (buf,				       \
+	     ((is_tbnz) ? TBNZ: TBZ)		       \
+	     | ENCODE (bit >> 5, 1, 31) /* b5 */       \
+	     | ENCODE (bit, 5, 19) /* b40 */	       \
+	     | ENCODE (offset >> 2, 14, 5) /* imm14 */ \
+	     | ENCODE (rt.num, 5, 0))
+
+/* Write a NOP instruction into *BUF.  */
+
+#define emit_nop(buf) emit_insn (buf, NOP)
+
+int emit_insn (uint32_t *buf, uint32_t insn);
+
+int emit_load_store (uint32_t *buf, uint32_t size,
+		     enum aarch64_opcodes opcode,
+		     struct aarch64_register rt,
+		     struct aarch64_register rn,
+		     struct aarch64_memory_operand operand);
+
 #endif
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 6d3d66d..3281026 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,5 +1,17 @@
 2015-10-12  Yao Qi  <yao.qi@linaro.org>
 
+	* linux-aarch64-low.c (enum aarch64_opcodes): Move to
+	arch/aarch64-insn.h.
+	(struct aarch64_memory_operand): Likewise.
+	(ENCODE): Likewise.
+	(emit_insn): Move to arch/aarch64-insn.c.
+	(emit_b, emit_bcond, emit_cb, emit_tb): Remove.
+	(emit_load_store): Move to arch/aarch64-insn.c.
+	(emit_ldr, emit_ldrb, emit_ldrsw, emit_nop): Remove.
+	(can_encode_int32): Remove.
+
+2015-10-12  Yao Qi  <yao.qi@linaro.org>
+
 	* linux-aarch64-low.c (extract_signed_bitfield): Remove.
 	(aarch64_decode_ldr_literal): Move to gdb/arch/aarch64-insn.c.
 	(aarch64_relocate_instruction): Likewise.
diff --git a/gdb/gdbserver/linux-aarch64-low.c b/gdb/gdbserver/linux-aarch64-low.c
index 1241434..9450449 100644
--- a/gdb/gdbserver/linux-aarch64-low.c
+++ b/gdb/gdbserver/linux-aarch64-low.c
@@ -584,92 +584,6 @@ aarch64_get_thread_area (int lwpid, CORE_ADDR *addrp)
   return 0;
 }
 
-/* List of opcodes that we need for building the jump pad and relocating
-   an instruction.  */
-
-enum aarch64_opcodes
-{
-  /* B              0001 01ii iiii iiii iiii iiii iiii iiii */
-  /* BL             1001 01ii iiii iiii iiii iiii iiii iiii */
-  /* B.COND         0101 0100 iiii iiii iiii iiii iii0 cccc */
-  /* CBZ            s011 0100 iiii iiii iiii iiii iiir rrrr */
-  /* CBNZ           s011 0101 iiii iiii iiii iiii iiir rrrr */
-  /* TBZ            b011 0110 bbbb biii iiii iiii iiir rrrr */
-  /* TBNZ           b011 0111 bbbb biii iiii iiii iiir rrrr */
-  B               = 0x14000000,
-  BL              = 0x80000000 | B,
-  BCOND           = 0x40000000 | B,
-  CBZ             = 0x20000000 | B,
-  CBNZ            = 0x21000000 | B,
-  TBZ             = 0x36000000 | B,
-  TBNZ            = 0x37000000 | B,
-  /* BLR            1101 0110 0011 1111 0000 00rr rrr0 0000 */
-  BLR             = 0xd63f0000,
-  /* RET            1101 0110 0101 1111 0000 00rr rrr0 0000 */
-  RET             = 0xd65f0000,
-  /* STP            s010 100o o0ii iiii irrr rrrr rrrr rrrr */
-  /* LDP            s010 100o o1ii iiii irrr rrrr rrrr rrrr */
-  /* STP (SIMD&VFP) ss10 110o o0ii iiii irrr rrrr rrrr rrrr */
-  /* LDP (SIMD&VFP) ss10 110o o1ii iiii irrr rrrr rrrr rrrr */
-  STP             = 0x28000000,
-  LDP             = 0x28400000,
-  STP_SIMD_VFP    = 0x04000000 | STP,
-  LDP_SIMD_VFP    = 0x04000000 | LDP,
-  /* STR            ss11 100o 00xi iiii iiii xxrr rrrr rrrr */
-  /* LDR            ss11 100o 01xi iiii iiii xxrr rrrr rrrr */
-  /* LDRSW          1011 100o 10xi iiii iiii xxrr rrrr rrrr */
-  STR             = 0x38000000,
-  LDR             = 0x00400000 | STR,
-  LDRSW           = 0x80800000 | STR,
-  /* LDAXR          ss00 1000 0101 1111 1111 11rr rrrr rrrr */
-  LDAXR           = 0x085ffc00,
-  /* STXR           ss00 1000 000r rrrr 0111 11rr rrrr rrrr */
-  STXR            = 0x08007c00,
-  /* STLR           ss00 1000 1001 1111 1111 11rr rrrr rrrr */
-  STLR            = 0x089ffc00,
-  /* MOV            s101 0010 1xxi iiii iiii iiii iiir rrrr */
-  /* MOVK           s111 0010 1xxi iiii iiii iiii iiir rrrr */
-  MOV             = 0x52800000,
-  MOVK            = 0x20000000 | MOV,
-  /* ADD            s00o ooo1 xxxx xxxx xxxx xxxx xxxx xxxx */
-  /* SUB            s10o ooo1 xxxx xxxx xxxx xxxx xxxx xxxx */
-  /* SUBS           s11o ooo1 xxxx xxxx xxxx xxxx xxxx xxxx */
-  ADD             = 0x01000000,
-  SUB             = 0x40000000 | ADD,
-  SUBS            = 0x20000000 | SUB,
-  /* AND            s000 1010 xx0x xxxx xxxx xxxx xxxx xxxx */
-  /* ORR            s010 1010 xx0x xxxx xxxx xxxx xxxx xxxx */
-  /* ORN            s010 1010 xx1x xxxx xxxx xxxx xxxx xxxx */
-  /* EOR            s100 1010 xx0x xxxx xxxx xxxx xxxx xxxx */
-  AND             = 0x0a000000,
-  ORR             = 0x20000000 | AND,
-  ORN             = 0x00200000 | ORR,
-  EOR             = 0x40000000 | AND,
-  /* LSLV           s001 1010 110r rrrr 0010 00rr rrrr rrrr */
-  /* LSRV           s001 1010 110r rrrr 0010 01rr rrrr rrrr */
-  /* ASRV           s001 1010 110r rrrr 0010 10rr rrrr rrrr */
-  LSLV             = 0x1ac02000,
-  LSRV             = 0x00000400 | LSLV,
-  ASRV             = 0x00000800 | LSLV,
-  /* SBFM           s001 0011 0nii iiii iiii iirr rrrr rrrr */
-  SBFM            = 0x13000000,
-  /* UBFM           s101 0011 0nii iiii iiii iirr rrrr rrrr */
-  UBFM            = 0x40000000 | SBFM,
-  /* CSINC          s001 1010 100r rrrr cccc 01rr rrrr rrrr */
-  CSINC           = 0x9a800400,
-  /* MUL            s001 1011 000r rrrr 0111 11rr rrrr rrrr */
-  MUL             = 0x1b007c00,
-  /* MSR (register) 1101 0101 0001 oooo oooo oooo ooor rrrr */
-  /* MRS            1101 0101 0011 oooo oooo oooo ooor rrrr */
-  MSR             = 0xd5100000,
-  MRS             = 0x00200000 | MSR,
-  /* HINT           1101 0101 0000 0011 0010 oooo ooo1 1111 */
-  HINT            = 0xd503201f,
-  SEVL            = (5 << 5) | HINT,
-  WFE             = (2 << 5) | HINT,
-  NOP             = (0 << 5) | HINT,
-};
-
 /* List of condition codes that we need.  */
 
 enum aarch64_condition_codes
@@ -683,16 +597,6 @@ enum aarch64_condition_codes
   LE = 0xd,
 };
 
-/* Representation of a general purpose register of the form xN or wN.
-
-   This type is used by emitting functions that take registers as operands.  */
-
-struct aarch64_register
-{
-  unsigned num;
-  int is64;
-};
-
 /* Representation of an operand.  At this time, it only supports register
    and immediate types.  */
 
@@ -779,28 +683,6 @@ immediate_operand (uint32_t imm)
   return operand;
 }
 
-/* Representation of a memory operand, used for load and store
-   instructions.
-
-   The types correspond to the following variants:
-
-   MEMORY_OPERAND_OFFSET:    LDR rt, [rn, #offset]
-   MEMORY_OPERAND_PREINDEX:  LDR rt, [rn, #index]!
-   MEMORY_OPERAND_POSTINDEX: LDR rt, [rn], #index  */
-
-struct aarch64_memory_operand
-{
-  /* Type of the operand.  */
-  enum
-    {
-      MEMORY_OPERAND_OFFSET,
-      MEMORY_OPERAND_PREINDEX,
-      MEMORY_OPERAND_POSTINDEX,
-    } type;
-  /* Index from the base register.  */
-  int32_t index;
-};
-
 /* Helper function to create an offset memory operand.
 
    For example:
@@ -852,108 +734,6 @@ enum aarch64_system_control_registers
   TPIDR_EL0 = (0x1 << 14) | (0x3 << 11) | (0xd << 7) | (0x0 << 3) | 0x2
 };
 
-/* Helper macro to mask and shift a value into a bitfield.  */
-
-#define ENCODE(val, size, offset) \
-  ((uint32_t) ((val & ((1ULL << size) - 1)) << offset))
-
-/* Write a 32-bit unsigned integer INSN info *BUF.  Return the number of
-   instructions written (aka. 1).  */
-
-static int
-emit_insn (uint32_t *buf, uint32_t insn)
-{
-  *buf = insn;
-  return 1;
-}
-
-/* Write a B or BL instruction into *BUF.
-
-     B  #offset
-     BL #offset
-
-   IS_BL specifies if the link register should be updated.
-   OFFSET is the immediate offset from the current PC.  It is
-   byte-addressed but should be 4 bytes aligned.  It has a limited range of
-   +/- 128MB (26 bits << 2).  */
-
-static int
-emit_b (uint32_t *buf, int is_bl, int32_t offset)
-{
-  uint32_t imm26 = ENCODE (offset >> 2, 26, 0);
-
-  if (is_bl)
-    return emit_insn (buf, BL | imm26);
-  else
-    return emit_insn (buf, B | imm26);
-}
-
-/* Write a BCOND instruction into *BUF.
-
-     B.COND #offset
-
-   COND specifies the condition field.
-   OFFSET is the immediate offset from the current PC.  It is
-   byte-addressed but should be 4 bytes aligned.  It has a limited range of
-   +/- 1MB (19 bits << 2).  */
-
-static int
-emit_bcond (uint32_t *buf, unsigned cond, int32_t offset)
-{
-  return emit_insn (buf, BCOND | ENCODE (offset >> 2, 19, 5)
-		    | ENCODE (cond, 4, 0));
-}
-
-/* Write a CBZ or CBNZ instruction into *BUF.
-
-     CBZ  rt, #offset
-     CBNZ rt, #offset
-
-   IS_CBNZ distinguishes between CBZ and CBNZ instructions.
-   RN is the register to test.
-   OFFSET is the immediate offset from the current PC.  It is
-   byte-addressed but should be 4 bytes aligned.  It has a limited range of
-   +/- 1MB (19 bits << 2).  */
-
-static int
-emit_cb (uint32_t *buf, int is_cbnz, struct aarch64_register rt,
-	 int32_t offset)
-{
-  uint32_t imm19 = ENCODE (offset >> 2, 19, 5);
-  uint32_t sf = ENCODE (rt.is64, 1, 31);
-
-  if (is_cbnz)
-    return emit_insn (buf, CBNZ | sf | imm19 | ENCODE (rt.num, 5, 0));
-  else
-    return emit_insn (buf, CBZ | sf | imm19 | ENCODE (rt.num, 5, 0));
-}
-
-/* Write a TBZ or TBNZ instruction into *BUF.
-
-     TBZ  rt, #bit, #offset
-     TBNZ rt, #bit, #offset
-
-   IS_TBNZ distinguishes between TBZ and TBNZ instructions.
-   RT is the register to test.
-   BIT is the index of the bit to test in register RT.
-   OFFSET is the immediate offset from the current PC.  It is
-   byte-addressed but should be 4 bytes aligned.  It has a limited range of
-   +/- 32KB (14 bits << 2).  */
-
-static int
-emit_tb (uint32_t *buf, int is_tbnz, unsigned bit,
-	 struct aarch64_register rt, int32_t offset)
-{
-  uint32_t imm14 = ENCODE (offset >> 2, 14, 5);
-  uint32_t b40 = ENCODE (bit, 5, 19);
-  uint32_t b5 = ENCODE (bit >> 5, 1, 31);
-
-  if (is_tbnz)
-    return emit_insn (buf, TBNZ | b5 | b40 | imm14 | ENCODE (rt.num, 5, 0));
-  else
-    return emit_insn (buf, TBZ | b5 | b40 | imm14 | ENCODE (rt.num, 5, 0));
-}
-
 /* Write a BLR instruction into *BUF.
 
      BLR rn
@@ -1100,70 +880,9 @@ emit_stp_q_offset (uint32_t *buf, unsigned rt, unsigned rt2,
   uint32_t pre_index = ENCODE (1, 1, 24);
 
   return emit_insn (buf, STP_SIMD_VFP | opc | pre_index
-		    | ENCODE (offset >> 4, 7, 15) | ENCODE (rt2, 5, 10)
-		    | ENCODE (rn.num, 5, 5) | ENCODE (rt, 5, 0));
-}
-
-/* Helper function emitting a load or store instruction.  */
-
-static int
-emit_load_store (uint32_t *buf, uint32_t size, enum aarch64_opcodes opcode,
-		 struct aarch64_register rt, struct aarch64_register rn,
-		 struct aarch64_memory_operand operand)
-{
-  uint32_t op;
-
-  switch (operand.type)
-    {
-    case MEMORY_OPERAND_OFFSET:
-      {
-	op = ENCODE (1, 1, 24);
-
-	return emit_insn (buf, opcode | ENCODE (size, 2, 30) | op
-			  | ENCODE (operand.index >> 3, 12, 10)
-			  | ENCODE (rn.num, 5, 5) | ENCODE (rt.num, 5, 0));
-      }
-    case MEMORY_OPERAND_POSTINDEX:
-      {
-	uint32_t post_index = ENCODE (1, 2, 10);
-
-	op = ENCODE (0, 1, 24);
-
-	return emit_insn (buf, opcode | ENCODE (size, 2, 30) | op
-			  | post_index | ENCODE (operand.index, 9, 12)
-			  | ENCODE (rn.num, 5, 5) | ENCODE (rt.num, 5, 0));
-      }
-    case MEMORY_OPERAND_PREINDEX:
-      {
-	uint32_t pre_index = ENCODE (3, 2, 10);
-
-	op = ENCODE (0, 1, 24);
-
-	return emit_insn (buf, opcode | ENCODE (size, 2, 30) | op
-			  | pre_index | ENCODE (operand.index, 9, 12)
-			  | ENCODE (rn.num, 5, 5) | ENCODE (rt.num, 5, 0));
-      }
-    default:
-      return 0;
-    }
-}
-
-/* Write a LDR instruction into *BUF.
-
-     LDR rt, [rn, #offset]
-     LDR rt, [rn, #index]!
-     LDR rt, [rn], #index
-
-   RT is the register to store.
-   RN is the base address register.
-   OFFSET is the immediate to add to the base address.  It is limited to
-   0 .. 32760 range (12 bits << 3).  */
-
-static int
-emit_ldr (uint32_t *buf, struct aarch64_register rt,
-	  struct aarch64_register rn, struct aarch64_memory_operand operand)
-{
-  return emit_load_store (buf, rt.is64 ? 3 : 2, LDR, rt, rn, operand);
+			    | ENCODE (offset >> 4, 7, 15)
+			    | ENCODE (rt2, 5, 10)
+			    | ENCODE (rn.num, 5, 5) | ENCODE (rt, 5, 0));
 }
 
 /* Write a LDRH instruction into *BUF.
@@ -1204,24 +923,7 @@ emit_ldrb (uint32_t *buf, struct aarch64_register rt,
   return emit_load_store (buf, 0, LDR, rt, rn, operand);
 }
 
-/* Write a LDRSW instruction into *BUF.  The register size is 64-bit.
 
-     LDRSW xt, [rn, #offset]
-     LDRSW xt, [rn, #index]!
-     LDRSW xt, [rn], #index
-
-   RT is the register to store.
-   RN is the base address register.
-   OFFSET is the immediate to add to the base address.  It is limited to
-   0 .. 16380 range (12 bits << 2).  */
-
-static int
-emit_ldrsw (uint32_t *buf, struct aarch64_register rt,
-		   struct aarch64_register rn,
-		   struct aarch64_memory_operand operand)
-{
-  return emit_load_store (buf, 3, LDRSW, rt, rn, operand);
-}
 
 /* Write a STR instruction into *BUF.
 
@@ -1816,14 +1518,6 @@ emit_cset (uint32_t *buf, struct aarch64_register rd, unsigned cond)
   return emit_csinc (buf, rd, xzr, xzr, cond ^ 0x1);
 }
 
-/* Write a NOP instruction into *BUF.  */
-
-static int
-emit_nop (uint32_t *buf)
-{
-  return emit_insn (buf, NOP);
-}
-
 /* Write LEN instructions from BUF into the inferior memory at *TO.
 
    Note instructions are always little endian on AArch64, unlike data.  */
@@ -1849,17 +1543,6 @@ append_insns (CORE_ADDR *to, size_t len, const uint32_t *buf)
   *to += byte_len;
 }
 
-/* Helper function.  Return 1 if VAL can be encoded in BITS bits.  */
-
-static int
-can_encode_int32 (int32_t val, unsigned bits)
-{
-  /* This must be an arithemic shift.  */
-  int32_t rest = val >> bits;
-
-  return rest == 0 || rest == -1;
-}
-
 /* Sub-class of struct aarch64_insn_data, store information of
    instruction relocation for fast tracepoint.  Visitor can
    relocate an instruction from BASE.INSN_ADDR to NEW_ADDR and save