[PowerPC] Add ROP Protection Instructions for PowerPC

There are four new PowerPC instructions that are introduced in
Power 10. They are hashst, hashchk, hashstp, hashchkp.

These instructions will be used for ROP Protection.
This patch adds the four instructions.

Reviewed By: nemanjai, amyk, #powerpc

Differential Revision: https://reviews.llvm.org/D99375

1 files changed, 17 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/Disassembler/PPCDisassembler.cpp b/llvm/lib/Target/PowerPC/Disassembler/PPCDisassembler.cpp
index 3e9286f..44f9920 100644
--- a/llvm/lib/Target/PowerPC/Disassembler/PPCDisassembler.cpp
+++ b/llvm/lib/Target/PowerPC/Disassembler/PPCDisassembler.cpp
@@ -279,6 +279,23 @@ static DecodeStatus decodeMemRIXOperands(MCInst &Inst, uint64_t Imm,
   return MCDisassembler::Success;
 }
 
+static DecodeStatus decodeMemRIHashOperands(MCInst &Inst, uint64_t Imm,
+                                            int64_t Address,
+                                            const void *Decoder) {
+  // Decode the memrix field for a hash store or hash check operation.
+  // The field is composed of a register and an immediate value that is 6 bits
+  // and covers the range -8 to -512. The immediate is always negative and 2s
+  // complement which is why we sign extend a 7 bit value.
+  const uint64_t Base = Imm >> 6;
+  const int64_t Disp = SignExtend64<7>((Imm & 0x3F) + 64) * 8;
+
+  assert(Base < 32 && "Invalid base register");
+
+  Inst.addOperand(MCOperand::createImm(Disp));
+  Inst.addOperand(MCOperand::createReg(RRegs[Base]));
+  return MCDisassembler::Success;
+}
+
 static DecodeStatus decodeMemRIX16Operands(MCInst &Inst, uint64_t Imm,
                                          int64_t Address, const void *Decoder) {
   // Decode the memrix16 field (imm, reg), which has the low 12-bits as the