Use aarch64_decode_insn in aarch64_analyze_prologue

This patch convert aarch64_analyze_prologue to using aarch64_decode_insn
to decode instructions.  After this change, aarch64_analyze_prologue
looks much simple, and some aarch64_decode_* functions are removed
accordingly.

gdb:

2015-11-05  Yao Qi  <yao.qi@linaro.org>

	* aarch64-tdep.c (extract_signed_bitfield): Remove.
	(decode_masked_match): Remove.
	(aarch64_decode_add_sub_imm): Remove.
	(aarch64_decode_br): Remove.
	(aarch64_decode_eret): Remove.
	(aarch64_decode_movz): Remove.
	(aarch64_decode_orr_shifted_register_x): Remove.
	(aarch64_decode_ret): Remove.
	(aarch64_decode_stp_offset): Remove.
	(aarch64_decode_stur): Remove.
	(aarch64_analyze_prologue): Call aarch64_decode_insn
	and use aarch64_inst to decode instructions.

1 files changed, 83 insertions, 343 deletions

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index d84c034..4bdd227 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -194,302 +194,6 @@ show_aarch64_debug (struct ui_file *file, int from_tty,
   fprintf_filtered (file, _("AArch64 debugging is %s.\n"), value);
 }
 
-/* Extract a signed value from a bit field within an instruction
-   encoding.
-
-   INSN is the instruction opcode.
-
-   WIDTH specifies the width of the bit field to extract (in bits).
-
-   OFFSET specifies the least significant bit of the field where bits
-   are numbered zero counting from least to most significant.  */
-
-static int32_t
-extract_signed_bitfield (uint32_t insn, unsigned width, unsigned offset)
-{
-  unsigned shift_l = sizeof (int32_t) * 8 - (offset + width);
-  unsigned shift_r = sizeof (int32_t) * 8 - width;
-
-  return ((int32_t) insn << shift_l) >> shift_r;
-}
-
-/* Determine if specified bits within an instruction opcode matches a
-   specific pattern.
-
-   INSN is the instruction opcode.
-
-   MASK specifies the bits within the opcode that are to be tested
-   agsinst for a match with PATTERN.  */
-
-static int
-decode_masked_match (uint32_t insn, uint32_t mask, uint32_t pattern)
-{
-  return (insn & mask) == pattern;
-}
-
-/* Decode an opcode if it represents an immediate ADD or SUB instruction.
-
-   ADDR specifies the address of the opcode.
-   INSN specifies the opcode to test.
-   RD receives the 'rd' field from the decoded instruction.
-   RN receives the 'rn' field from the decoded instruction.
-
-   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
-static int
-aarch64_decode_add_sub_imm (CORE_ADDR addr, uint32_t insn, unsigned *rd,
-			    unsigned *rn, int32_t *imm)
-{
-  if ((insn & 0x9f000000) == 0x91000000)
-    {
-      unsigned shift;
-      unsigned op_is_sub;
-
-      *rd = (insn >> 0) & 0x1f;
-      *rn = (insn >> 5) & 0x1f;
-      *imm = (insn >> 10) & 0xfff;
-      shift = (insn >> 22) & 0x3;
-      op_is_sub = (insn >> 30) & 0x1;
-
-      switch (shift)
-	{
-	case 0:
-	  break;
-	case 1:
-	  *imm <<= 12;
-	  break;
-	default:
-	  /* UNDEFINED */
-	  return 0;
-	}
-
-      if (op_is_sub)
-	*imm = -*imm;
-
-      if (aarch64_debug)
-	{
-	  debug_printf ("decode: 0x%s 0x%x add x%u, x%u, #%d\n",
-			core_addr_to_string_nz (addr), insn, *rd, *rn,
-			*imm);
-	}
-      return 1;
-    }
-  return 0;
-}
-
-/* Decode an opcode if it represents a branch via register instruction.
-
-   ADDR specifies the address of the opcode.
-   INSN specifies the opcode to test.
-   IS_BLR receives the 'op' bit from the decoded instruction.
-   RN receives the 'rn' field from the decoded instruction.
-
-   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
-
-static int
-aarch64_decode_br (CORE_ADDR addr, uint32_t insn, int *is_blr,
-		   unsigned *rn)
-{
-  /*         8   4   0   6   2   8   4   0 */
-  /* blr  110101100011111100000000000rrrrr */
-  /* br   110101100001111100000000000rrrrr */
-  if (decode_masked_match (insn, 0xffdffc1f, 0xd61f0000))
-    {
-      *is_blr = (insn >> 21) & 1;
-      *rn = (insn >> 5) & 0x1f;
-
-      if (aarch64_debug)
-	{
-	  debug_printf ("decode: 0x%s 0x%x %s 0x%x\n",
-			core_addr_to_string_nz (addr), insn,
-			*is_blr ?  "blr" : "br", *rn);
-	}
-
-      return 1;
-    }
-  return 0;
-}
-
-/* Decode an opcode if it represents a ERET instruction.
-
-   ADDR specifies the address of the opcode.
-   INSN specifies the opcode to test.
-
-   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
-
-static int
-aarch64_decode_eret (CORE_ADDR addr, uint32_t insn)
-{
-  /* eret 1101 0110 1001 1111 0000 0011 1110 0000 */
-  if (insn == 0xd69f03e0)
-    {
-      if (aarch64_debug)
-	{
-	  debug_printf ("decode: 0x%s 0x%x eret\n",
-			core_addr_to_string_nz (addr), insn);
-	}
-      return 1;
-    }
-  return 0;
-}
-
-/* Decode an opcode if it represents a MOVZ instruction.
-
-   ADDR specifies the address of the opcode.
-   INSN specifies the opcode to test.
-   RD receives the 'rd' field from the decoded instruction.
-
-   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
-
-static int
-aarch64_decode_movz (CORE_ADDR addr, uint32_t insn, unsigned *rd)
-{
-  if (decode_masked_match (insn, 0xff800000, 0x52800000))
-    {
-      *rd = (insn >> 0) & 0x1f;
-
-      if (aarch64_debug)
-	{
-	  debug_printf ("decode: 0x%s 0x%x movz x%u, #?\n",
-			core_addr_to_string_nz (addr), insn, *rd);
-	}
-      return 1;
-    }
-  return 0;
-}
-
-/* Decode an opcode if it represents a ORR (shifted register)
-   instruction.
-
-   ADDR specifies the address of the opcode.
-   INSN specifies the opcode to test.
-   RD receives the 'rd' field from the decoded instruction.
-   RN receives the 'rn' field from the decoded instruction.
-   RM receives the 'rm' field from the decoded instruction.
-   IMM receives the 'imm6' field from the decoded instruction.
-
-   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
-
-static int
-aarch64_decode_orr_shifted_register_x (CORE_ADDR addr, uint32_t insn,
-				       unsigned *rd, unsigned *rn,
-				       unsigned *rm, int32_t *imm)
-{
-  if (decode_masked_match (insn, 0xff200000, 0xaa000000))
-    {
-      *rd = (insn >> 0) & 0x1f;
-      *rn = (insn >> 5) & 0x1f;
-      *rm = (insn >> 16) & 0x1f;
-      *imm = (insn >> 10) & 0x3f;
-
-      if (aarch64_debug)
-	{
-	  debug_printf ("decode: 0x%s 0x%x orr x%u, x%u, x%u, #%u\n",
-			core_addr_to_string_nz (addr), insn, *rd, *rn,
-			*rm, *imm);
-	}
-      return 1;
-    }
-  return 0;
-}
-
-/* Decode an opcode if it represents a RET instruction.
-
-   ADDR specifies the address of the opcode.
-   INSN specifies the opcode to test.
-   RN receives the 'rn' field from the decoded instruction.
-
-   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
-
-static int
-aarch64_decode_ret (CORE_ADDR addr, uint32_t insn, unsigned *rn)
-{
-  if (decode_masked_match (insn, 0xfffffc1f, 0xd65f0000))
-    {
-      *rn = (insn >> 5) & 0x1f;
-      if (aarch64_debug)
-	{
-	  debug_printf ("decode: 0x%s 0x%x ret x%u\n",
-			core_addr_to_string_nz (addr), insn, *rn);
-	}
-      return 1;
-    }
-  return 0;
-}
-
-/* Decode an opcode if it represents the following instructions:
-
-   STP rt, rt2, [rn, #imm]
-   STP rt, rt2, [rn, #imm]!
-
-   ADDR specifies the address of the opcode.
-   INSN specifies the opcode to test.
-   RT1 receives the 'rt' field from the decoded instruction.
-   RT2 receives the 'rt2' field from the decoded instruction.
-   RN receives the 'rn' field from the decoded instruction.
-   IMM receives the 'imm' field from the decoded instruction.
-   *WBACK receives the bit 23 from the decoded instruction.
-
-   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
-
-static int
-aarch64_decode_stp_offset (CORE_ADDR addr, uint32_t insn, unsigned *rt1,
-			   unsigned *rt2, unsigned *rn, int32_t *imm,
-			   int *wback)
-{
-  if (decode_masked_match (insn, 0xff400000, 0xa9000000))
-    {
-      *rt1 = (insn >> 0) & 0x1f;
-      *rn = (insn >> 5) & 0x1f;
-      *rt2 = (insn >> 10) & 0x1f;
-      *imm = extract_signed_bitfield (insn, 7, 15);
-      *imm <<= 3;
-      *wback = bit (insn, 23);
-
-      if (aarch64_debug)
-	{
-	  debug_printf ("decode: 0x%s 0x%x stp x%u, x%u, [x%u + #%d]%s\n",
-			core_addr_to_string_nz (addr), insn, *rt1, *rt2,
-			*rn, *imm, *wback ? "" : "!");
-	}
-      return 1;
-    }
-  return 0;
-}
-
-/* Decode an opcode if it represents the following instruction:
-   STUR rt, [rn, #imm]
-
-   ADDR specifies the address of the opcode.
-   INSN specifies the opcode to test.
-   IS64 receives size field from the decoded instruction.
-   RT receives the 'rt' field from the decoded instruction.
-   RN receives the 'rn' field from the decoded instruction.
-   IMM receives the 'imm' field from the decoded instruction.
-
-   Return 1 if the opcodes matches and is decoded, otherwise 0.  */
-
-static int
-aarch64_decode_stur (CORE_ADDR addr, uint32_t insn, int *is64,
-		     unsigned *rt, unsigned *rn, int32_t *imm)
-{
-  if (decode_masked_match (insn, 0xbfe00c00, 0xb8000000))
-    {
-      *is64 = (insn >> 30) & 1;
-      *rt = (insn >> 0) & 0x1f;
-      *rn = (insn >> 5) & 0x1f;
-      *imm = extract_signed_bitfield (insn, 9, 12);
-
-      if (aarch64_debug)
-	{
-	  debug_printf ("decode: 0x%s 0x%x stur %c%u, [x%u + #%d]\n",
-			core_addr_to_string_nz (addr), insn,
-			*is64 ? 'x' : 'w', *rt, *rn, *imm);
-	}
-      return 1;
-    }
-  return 0;
-}
-
 /* Analyze a prologue, looking for a recognizable stack frame
    and frame pointer.  Scan until we encounter a store that could
    clobber the stack frame unexpectedly, or an unknown instruction.  */
@@ -513,63 +217,82 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
   for (; start < limit; start += 4)
     {
       uint32_t insn;
-      unsigned rd;
-      unsigned rn;
-      unsigned rm;
-      unsigned rt;
-      unsigned rt1;
-      unsigned rt2;
-      int op_is_sub;
-      int wback;
-      int32_t imm;
-      unsigned cond;
-      int is64;
-      int is_link;
-      int is_cbnz;
-      int is_tbnz;
-      unsigned bit;
-      int is_adrp;
-      int32_t offset;
+      aarch64_inst inst;
 
       insn = read_memory_unsigned_integer (start, 4, byte_order_for_code);
 
-      if (aarch64_decode_add_sub_imm (start, insn, &rd, &rn, &imm))
-	regs[rd] = pv_add_constant (regs[rn], imm);
-      else if (aarch64_decode_adr (start, insn, &is_adrp, &rd, &offset)
-	       && is_adrp)
-	regs[rd] = pv_unknown ();
-      else if (aarch64_decode_b (start, insn, &is_link, &offset))
+      if (aarch64_decode_insn (insn, &inst, 1) != 0)
+	break;
+
+      if (inst.opcode->iclass == addsub_imm
+	  && (inst.opcode->op == OP_ADD
+	      || strcmp ("sub", inst.opcode->name) == 0))
 	{
-	  /* Stop analysis on branch.  */
-	  break;
+	  unsigned rd = inst.operands[0].reg.regno;
+	  unsigned rn = inst.operands[1].reg.regno;
+
+	  gdb_assert (aarch64_num_of_operands (inst.opcode) == 3);
+	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rd_SP);
+	  gdb_assert (inst.operands[1].type == AARCH64_OPND_Rn_SP);
+	  gdb_assert (inst.operands[2].type == AARCH64_OPND_AIMM);
+
+	  if (inst.opcode->op == OP_ADD)
+	    {
+	      regs[rd] = pv_add_constant (regs[rn],
+					  inst.operands[2].imm.value);
+	    }
+	  else
+	    {
+	      regs[rd] = pv_add_constant (regs[rn],
+					  -inst.operands[2].imm.value);
+	    }
+	}
+      else if (inst.opcode->iclass == pcreladdr
+	       && inst.operands[1].type == AARCH64_OPND_ADDR_ADRP)
+	{
+	  gdb_assert (aarch64_num_of_operands (inst.opcode) == 2);
+	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rd);
+
+	  regs[inst.operands[0].reg.regno] = pv_unknown ();
 	}
-      else if (aarch64_decode_bcond (start, insn, &cond, &offset))
+      else if (inst.opcode->iclass == branch_imm)
 	{
 	  /* Stop analysis on branch.  */
 	  break;
 	}
-      else if (aarch64_decode_br (start, insn, &is_link, &rn))
+      else if (inst.opcode->iclass == condbranch)
 	{
 	  /* Stop analysis on branch.  */
 	  break;
 	}
-      else if (aarch64_decode_cb (start, insn, &is64, &is_cbnz, &rn,
-				  &offset))
+      else if (inst.opcode->iclass == branch_reg)
 	{
 	  /* Stop analysis on branch.  */
 	  break;
 	}
-      else if (aarch64_decode_eret (start, insn))
+      else if (inst.opcode->iclass == compbranch)
 	{
 	  /* Stop analysis on branch.  */
 	  break;
 	}
-      else if (aarch64_decode_movz (start, insn, &rd))
-	regs[rd] = pv_unknown ();
-      else if (aarch64_decode_orr_shifted_register_x (start, insn, &rd,
-						      &rn, &rm, &imm))
+      else if (inst.opcode->op == OP_MOVZ)
 	{
-	  if (imm == 0 && rn == 31)
+	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rd);
+	  regs[inst.operands[0].reg.regno] = pv_unknown ();
+	}
+      else if (inst.opcode->iclass == log_shift
+	       && strcmp (inst.opcode->name, "orr") == 0)
+	{
+	  unsigned rd = inst.operands[0].reg.regno;
+	  unsigned rn = inst.operands[1].reg.regno;
+	  unsigned rm = inst.operands[2].reg.regno;
+
+	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rd);
+	  gdb_assert (inst.operands[1].type == AARCH64_OPND_Rn);
+	  gdb_assert (inst.operands[2].type == AARCH64_OPND_Rm_SFT);
+
+	  if (inst.operands[2].shifter.amount == 0
+	      && rn == AARCH64_SP_REGNUM)
 	    regs[rd] = regs[rm];
 	  else
 	    {
@@ -582,19 +305,37 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 	      break;
 	    }
 	}
-      else if (aarch64_decode_ret (start, insn, &rn))
-	{
-	  /* Stop analysis on branch.  */
-	  break;
-	}
-      else if (aarch64_decode_stur (start, insn, &is64, &rt, &rn, &offset))
+      else if (inst.opcode->op == OP_STUR)
 	{
-	  pv_area_store (stack, pv_add_constant (regs[rn], offset),
+	  unsigned rt = inst.operands[0].reg.regno;
+	  unsigned rn = inst.operands[1].addr.base_regno;
+	  int is64
+	    = (aarch64_get_qualifier_esize (inst.operands[0].qualifier) == 8);
+
+	  gdb_assert (aarch64_num_of_operands (inst.opcode) == 2);
+	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rt);
+	  gdb_assert (inst.operands[1].type == AARCH64_OPND_ADDR_SIMM9);
+	  gdb_assert (!inst.operands[1].addr.offset.is_reg);
+
+	  pv_area_store (stack, pv_add_constant (regs[rn],
+						 inst.operands[1].addr.offset.imm),
 			 is64 ? 8 : 4, regs[rt]);
 	}
-      else if (aarch64_decode_stp_offset (start, insn, &rt1, &rt2, &rn,
-					  &imm, &wback))
+      else if ((inst.opcode->iclass == ldstpair_off
+		|| inst.opcode->iclass == ldstpair_indexed)
+	       && inst.operands[2].addr.preind
+	       && strcmp ("stp", inst.opcode->name) == 0)
 	{
+	  unsigned rt1 = inst.operands[0].reg.regno;
+	  unsigned rt2 = inst.operands[1].reg.regno;
+	  unsigned rn = inst.operands[2].addr.base_regno;
+	  int32_t imm = inst.operands[2].addr.offset.imm;
+
+	  gdb_assert (inst.operands[0].type == AARCH64_OPND_Rt);
+	  gdb_assert (inst.operands[1].type == AARCH64_OPND_Rt2);
+	  gdb_assert (inst.operands[2].type == AARCH64_OPND_ADDR_SIMM7);
+	  gdb_assert (!inst.operands[2].addr.offset.is_reg);
+
 	  /* If recording this store would invalidate the store area
 	     (perhaps because rn is not known) then we should abandon
 	     further prologue analysis.  */
@@ -611,12 +352,11 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 	  pv_area_store (stack, pv_add_constant (regs[rn], imm + 8), 8,
 			 regs[rt2]);
 
-	  if (wback)
+	  if (inst.operands[2].addr.writeback)
 	    regs[rn] = pv_add_constant (regs[rn], imm);
 
 	}
-      else if (aarch64_decode_tb (start, insn, &is_tbnz, &bit, &rn,
-				  &offset))
+      else if (inst.opcode->iclass == testbranch)
 	{
 	  /* Stop analysis on branch.  */
 	  break;