Move aarch64_relocate_instruction to arch/aarch64-insn.c

This patch moves aarch64_relocate_instruction and visitor class to
arch/aarch64-insn.c, so that both GDB and GDBserver can use it.

gdb:

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.
	* arch/aarch64-insn.h (aarch64_decode_ldr_literal): Declare.
	(struct aarch64_insn_data): Moved from
	gdbserver/linux-aarch64-low.c.
	(struct aarch64_insn_visitor): Likewise.
	(aarch64_relocate_instruction): Declare.

gdb/gdbserver:

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.
	(struct aarch64_insn_data): Move to gdb/arch/aarch64-insn.h.
	(struct aarch64_insn_visitor): Likewise.

2 files changed, 143 insertions, 0 deletions

diff --git a/gdb/arch/aarch64-insn.c b/gdb/arch/aarch64-insn.c
index 13d0013d6e9..d0e88fa88d1 100644
--- a/gdb/arch/aarch64-insn.c
+++ b/gdb/arch/aarch64-insn.c
@@ -235,3 +235,96 @@ aarch64_decode_tb (CORE_ADDR addr, uint32_t insn, int *is_tbnz,
     }
   return 0;
 }
+
+/* Decode an opcode if it represents an LDR or LDRSW instruction taking a
+   literal offset from the current PC.
+
+   ADDR specifies the address of the opcode.
+   INSN specifies the opcode to test.
+   IS_W is set if the instruction is LDRSW.
+   IS64 receives size field from the decoded instruction.
+   RT receives the 'rt' field from the decoded instruction.
+   OFFSET receives the 'imm' field from the decoded instruction.
+
+   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
+
+int
+aarch64_decode_ldr_literal (CORE_ADDR addr, uint32_t insn, int *is_w,
+			    int *is64, unsigned *rt, int32_t *offset)
+{
+  /* LDR    0T01 1000 iiii iiii iiii iiii iiir rrrr */
+  /* LDRSW  1001 1000 iiii iiii iiii iiii iiir rrrr */
+  if ((insn & 0x3f000000) == 0x18000000)
+    {
+      *is_w = (insn >> 31) & 0x1;
+
+      if (*is_w)
+	{
+	  /* LDRSW always takes a 64-bit destination registers.  */
+	  *is64 = 1;
+	}
+      else
+	*is64 = (insn >> 30) & 0x1;
+
+      *rt = (insn >> 0) & 0x1f;
+      *offset = extract_signed_bitfield (insn, 19, 5) << 2;
+
+      if (aarch64_debug)
+	debug_printf ("decode: %s 0x%x %s %s%u, #?\n",
+		      core_addr_to_string_nz (addr), insn,
+		      *is_w ? "ldrsw" : "ldr",
+		      *is64 ? "x" : "w", *rt);
+
+      return 1;
+    }
+
+  return 0;
+}
+
+/* Visit an instruction INSN by VISITOR with all needed information in DATA.
+
+   PC relative instructions need to be handled specifically:
+
+   - B/BL
+   - B.COND
+   - CBZ/CBNZ
+   - TBZ/TBNZ
+   - ADR/ADRP
+   - LDR/LDRSW (literal)  */
+
+void
+aarch64_relocate_instruction (uint32_t insn,
+			      const struct aarch64_insn_visitor *visitor,
+			      struct aarch64_insn_data *data)
+{
+  int is_bl;
+  int is64;
+  int is_sw;
+  int is_cbnz;
+  int is_tbnz;
+  int is_adrp;
+  unsigned rn;
+  unsigned rt;
+  unsigned rd;
+  unsigned cond;
+  unsigned bit;
+  int32_t offset;
+
+  if (aarch64_decode_b (data->insn_addr, insn, &is_bl, &offset))
+    visitor->b (is_bl, offset, data);
+  else if (aarch64_decode_bcond (data->insn_addr, insn, &cond, &offset))
+    visitor->b_cond (cond, offset, data);
+  else if (aarch64_decode_cb (data->insn_addr, insn, &is64, &is_cbnz, &rn,
+			      &offset))
+    visitor->cb (offset, is_cbnz, rn, is64, data);
+  else if (aarch64_decode_tb (data->insn_addr, insn, &is_tbnz, &bit, &rt,
+			      &offset))
+    visitor->tb (offset, is_tbnz, rt, bit, data);
+  else if (aarch64_decode_adr (data->insn_addr, insn, &is_adrp, &rd, &offset))
+    visitor->adr (offset, rd, is_adrp, data);
+  else if (aarch64_decode_ldr_literal (data->insn_addr, insn, &is_sw, &is64,
+				       &rt, &offset))
+    visitor->ldr_literal (offset, is_sw, rt, is64, data);
+  else
+    visitor->others (insn, data);
+}
diff --git a/gdb/arch/aarch64-insn.h b/gdb/arch/aarch64-insn.h
index 2facb44aea8..47f671565bd 100644
--- a/gdb/arch/aarch64-insn.h
+++ b/gdb/arch/aarch64-insn.h
@@ -36,4 +36,54 @@ int aarch64_decode_cb (CORE_ADDR addr, uint32_t insn, int *is64,
 int aarch64_decode_tb (CORE_ADDR addr, uint32_t insn, int *is_tbnz,
 		       unsigned *bit, unsigned *rt, int32_t *imm);
 
+int aarch64_decode_ldr_literal (CORE_ADDR addr, uint32_t insn, int *is_w,
+				int *is64, unsigned *rt, int32_t *offset);
+
+/* Data passed to each method of aarch64_insn_visitor.  */
+
+struct aarch64_insn_data
+{
+  /* The instruction address.  */
+  CORE_ADDR insn_addr;
+};
+
+/* Visit different instructions by different methods.  */
+
+struct aarch64_insn_visitor
+{
+  /* Visit instruction B/BL OFFSET.  */
+  void (*b) (const int is_bl, const int32_t offset,
+	     struct aarch64_insn_data *data);
+
+  /* Visit instruction B.COND OFFSET.  */
+  void (*b_cond) (const unsigned cond, const int32_t offset,
+		  struct aarch64_insn_data *data);
+
+  /* Visit instruction CBZ/CBNZ Rn, OFFSET.  */
+  void (*cb) (const int32_t offset, const int is_cbnz,
+	      const unsigned rn, int is64,
+	      struct aarch64_insn_data *data);
+
+  /* Visit instruction TBZ/TBNZ Rt, #BIT, OFFSET.  */
+  void (*tb) (const int32_t offset, int is_tbnz,
+	      const unsigned rt, unsigned bit,
+	      struct aarch64_insn_data *data);
+
+  /* Visit instruction ADR/ADRP Rd, OFFSET.  */
+  void (*adr) (const int32_t offset, const unsigned rd,
+	       const int is_adrp, struct aarch64_insn_data *data);
+
+  /* Visit instruction LDR/LDRSW Rt, OFFSET.  */
+  void (*ldr_literal) (const int32_t offset, const int is_sw,
+		       const unsigned rt, const int is64,
+		       struct aarch64_insn_data *data);
+
+  /* Visit instruction INSN of other kinds.  */
+  void (*others) (const uint32_t insn, struct aarch64_insn_data *data);
+};
+
+void aarch64_relocate_instruction (uint32_t insn,
+				   const struct aarch64_insn_visitor *visitor,
+				   struct aarch64_insn_data *data);
+
 #endif