[mips] Add support for CRC ASE

This includes

  Instructions: crc32b, crc32h, crc32w, crc32d,
                crc32cb, crc32ch, crc32cw, crc32cd

  Assembler directives: .set crc, .set nocrc, .module crc, .module nocrc

  Attribute: crc

  .MIPS.abiflags: CRC (0x8000)

Patch by Vladimir Stefanovic.

Differential Revision: https://reviews.llvm.org/D44176

llvm-svn: 327511

1 files changed, 20 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
index 3d29a0d..2f9c286 100644
--- a/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
+++ b/llvm/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
@@ -517,6 +517,10 @@ template <typename InsnType>
 static DecodeStatus DecodeDEXT(MCInst &MI, InsnType Insn, uint64_t Address,
                                const void *Decoder);
 
+template <typename InsnType>
+static DecodeStatus DecodeCRC(MCInst &MI, InsnType Insn, uint64_t Address,
+                              const void *Decoder);
+
 static DecodeStatus DecodeRegListOperand(MCInst &Inst, unsigned Insn,
                                          uint64_t Address,
                                          const void *Decoder);
@@ -1129,6 +1133,22 @@ static DecodeStatus DecodeDINS(MCInst &MI, InsnType Insn, uint64_t Address,
 
   return MCDisassembler::Success;
 }
+
+// Auto-generated decoder wouldn't add the third operand for CRC32*.
+template <typename InsnType>
+static DecodeStatus DecodeCRC(MCInst &MI, InsnType Insn, uint64_t Address,
+                              const void *Decoder) {
+  InsnType Rs = fieldFromInstruction(Insn, 21, 5);
+  InsnType Rt = fieldFromInstruction(Insn, 16, 5);
+  MI.addOperand(MCOperand::createReg(getReg(Decoder, Mips::GPR32RegClassID,
+                                     Rt)));
+  MI.addOperand(MCOperand::createReg(getReg(Decoder, Mips::GPR32RegClassID,
+                                     Rs)));
+  MI.addOperand(MCOperand::createReg(getReg(Decoder, Mips::GPR32RegClassID,
+                                     Rt)));
+  return MCDisassembler::Success;
+}
+
 /// Read two bytes from the ArrayRef and return 16 bit halfword sorted
 /// according to the given endianness.
 static DecodeStatus readInstruction16(ArrayRef<uint8_t> Bytes, uint64_t Address,