1 files changed, 127 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp b/contrib/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
index 78a2021..1ea4abc 100644
--- a/contrib/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
+++ b/contrib/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
@@ -156,6 +156,9 @@ public:
 
   SDNode *SelectLIBM(SDNode *N);
 
+  SDNode *SelectReadRegister(SDNode *N);
+  SDNode *SelectWriteRegister(SDNode *N);
+
 // Include the pieces autogenerated from the target description.
 #include "AArch64GenDAGISel.inc"
 
@@ -2114,6 +2117,120 @@ AArch64DAGToDAGISel::SelectCVTFixedPosOperand(SDValue N, SDValue &FixedPos,
   return true;
 }
 
+// Inspects a register string of the form o0:op1:CRn:CRm:op2 gets the fields
+// of the string and obtains the integer values from them and combines these
+// into a single value to be used in the MRS/MSR instruction.
+static int getIntOperandFromRegisterString(StringRef RegString) {
+  SmallVector<StringRef, 5> Fields;
+  RegString.split(Fields, ":");
+
+  if (Fields.size() == 1)
+    return -1;
+
+  assert(Fields.size() == 5
+            && "Invalid number of fields in read register string");
+
+  SmallVector<int, 5> Ops;
+  bool AllIntFields = true;
+
+  for (StringRef Field : Fields) {
+    unsigned IntField;
+    AllIntFields &= !Field.getAsInteger(10, IntField);
+    Ops.push_back(IntField);
+  }
+
+  assert(AllIntFields &&
+          "Unexpected non-integer value in special register string.");
+
+  // Need to combine the integer fields of the string into a single value
+  // based on the bit encoding of MRS/MSR instruction.
+  return (Ops[0] << 14) | (Ops[1] << 11) | (Ops[2] << 7) |
+         (Ops[3] << 3) | (Ops[4]);
+}
+
+// Lower the read_register intrinsic to an MRS instruction node if the special
+// register string argument is either of the form detailed in the ALCE (the
+// form described in getIntOperandsFromRegsterString) or is a named register
+// known by the MRS SysReg mapper.
+SDNode *AArch64DAGToDAGISel::SelectReadRegister(SDNode *N) {
+  const MDNodeSDNode *MD = dyn_cast<MDNodeSDNode>(N->getOperand(1));
+  const MDString *RegString = dyn_cast<MDString>(MD->getMD()->getOperand(0));
+  SDLoc DL(N);
+
+  int Reg = getIntOperandFromRegisterString(RegString->getString());
+  if (Reg != -1)
+    return CurDAG->getMachineNode(AArch64::MRS, DL, N->getSimpleValueType(0),
+                                  MVT::Other,
+                                  CurDAG->getTargetConstant(Reg, DL, MVT::i32),
+                                  N->getOperand(0));
+
+  // Use the sysreg mapper to map the remaining possible strings to the
+  // value for the register to be used for the instruction operand.
+  AArch64SysReg::MRSMapper mapper;
+  bool IsValidSpecialReg;
+  Reg = mapper.fromString(RegString->getString(),
+                          Subtarget->getFeatureBits(),
+                          IsValidSpecialReg);
+  if (IsValidSpecialReg)
+    return CurDAG->getMachineNode(AArch64::MRS, DL, N->getSimpleValueType(0),
+                                  MVT::Other,
+                                  CurDAG->getTargetConstant(Reg, DL, MVT::i32),
+                                  N->getOperand(0));
+
+  return nullptr;
+}
+
+// Lower the write_register intrinsic to an MSR instruction node if the special
+// register string argument is either of the form detailed in the ALCE (the
+// form described in getIntOperandsFromRegsterString) or is a named register
+// known by the MSR SysReg mapper.
+SDNode *AArch64DAGToDAGISel::SelectWriteRegister(SDNode *N) {
+  const MDNodeSDNode *MD = dyn_cast<MDNodeSDNode>(N->getOperand(1));
+  const MDString *RegString = dyn_cast<MDString>(MD->getMD()->getOperand(0));
+  SDLoc DL(N);
+
+  int Reg = getIntOperandFromRegisterString(RegString->getString());
+  if (Reg != -1)
+    return CurDAG->getMachineNode(AArch64::MSR, DL, MVT::Other,
+                                  CurDAG->getTargetConstant(Reg, DL, MVT::i32),
+                                  N->getOperand(2), N->getOperand(0));
+
+  // Check if the register was one of those allowed as the pstatefield value in
+  // the MSR (immediate) instruction. To accept the values allowed in the
+  // pstatefield for the MSR (immediate) instruction, we also require that an
+  // immediate value has been provided as an argument, we know that this is
+  // the case as it has been ensured by semantic checking.
+  AArch64PState::PStateMapper PMapper;
+  bool IsValidSpecialReg;
+  Reg = PMapper.fromString(RegString->getString(),
+                           Subtarget->getFeatureBits(),
+                           IsValidSpecialReg);
+  if (IsValidSpecialReg) {
+    assert (isa<ConstantSDNode>(N->getOperand(2))
+              && "Expected a constant integer expression.");
+    uint64_t Immed = cast<ConstantSDNode>(N->getOperand(2))->getZExtValue();
+    return CurDAG->getMachineNode(AArch64::MSRpstate, DL, MVT::Other,
+                                  CurDAG->getTargetConstant(Reg, DL, MVT::i32),
+                                  CurDAG->getTargetConstant(Immed, DL, MVT::i16),
+                                  N->getOperand(0));
+  }
+
+  // Use the sysreg mapper to attempt to map the remaining possible strings
+  // to the value for the register to be used for the MSR (register)
+  // instruction operand.
+  AArch64SysReg::MSRMapper Mapper;
+  Reg = Mapper.fromString(RegString->getString(),
+                          Subtarget->getFeatureBits(),
+                          IsValidSpecialReg);
+
+  if (IsValidSpecialReg)
+    return CurDAG->getMachineNode(AArch64::MSR, DL, MVT::Other,
+                                  CurDAG->getTargetConstant(Reg, DL, MVT::i32),
+                                  N->getOperand(2), N->getOperand(0));
+
+  return nullptr;
+}
+
 SDNode *AArch64DAGToDAGISel::Select(SDNode *Node) {
   // Dump information about the Node being selected
   DEBUG(errs() << "Selecting: ");
@@ -2135,6 +2252,16 @@ SDNode *AArch64DAGToDAGISel::Select(SDNode *Node) {
   default:
     break;
 
+  case ISD::READ_REGISTER:
+    if (SDNode *Res = SelectReadRegister(Node))
+      return Res;
+    break;
+
+  case ISD::WRITE_REGISTER:
+    if (SDNode *Res = SelectWriteRegister(Node))
+      return Res;
+    break;
+
   case ISD::ADD:
     if (SDNode *I = SelectMLAV64LaneV128(Node))
       return I;