0006-Xtensa-Add-support-of-the-Xtensa-function-calls.patch

From d67ba5647aee970c0c51d292831320989ddf8b8e Mon Sep 17 00:00:00 2001
From: Andrei Safronov <safronov@espressif.com>
Date: Wed, 5 Apr 2023 00:58:38 +0300
Subject: [PATCH 006/158] [Xtensa] Add support of the Xtensa function calls

---
 .../lib/Target/Xtensa/XtensaFrameLowering.cpp |  20 ++
 llvm/lib/Target/Xtensa/XtensaFrameLowering.h  |   4 +
 llvm/lib/Target/Xtensa/XtensaISelLowering.cpp | 240 +++++++++++++++++-
 llvm/lib/Target/Xtensa/XtensaISelLowering.h   |  14 +
 llvm/lib/Target/Xtensa/XtensaInstrInfo.cpp    | 135 +++++++++-
 llvm/lib/Target/Xtensa/XtensaInstrInfo.h      |  27 ++
 llvm/lib/Target/Xtensa/XtensaInstrInfo.td     |  47 ++++
 llvm/lib/Target/Xtensa/XtensaMCInstLower.cpp  |  50 ++++
 llvm/lib/Target/Xtensa/XtensaMCInstLower.h    |   7 +
 llvm/lib/Target/Xtensa/XtensaOperands.td      |   2 +-
 llvm/lib/Target/Xtensa/XtensaOperators.td     |  26 +-
 llvm/lib/Target/Xtensa/XtensaRegisterInfo.cpp | 111 +++++++-
 llvm/lib/Target/Xtensa/XtensaRegisterInfo.h   |   5 +
 13 files changed, 678 insertions(+), 10 deletions(-)

diff --git a/llvm/lib/Target/Xtensa/XtensaFrameLowering.cpp b/llvm/lib/Target/Xtensa/XtensaFrameLowering.cpp
index b201b99813ce..71941e767193 100644
--- a/llvm/lib/Target/Xtensa/XtensaFrameLowering.cpp
+++ b/llvm/lib/Target/Xtensa/XtensaFrameLowering.cpp
@@ -42,3 +42,23 @@ void XtensaFrameLowering::emitPrologue(MachineFunction &MF,
 
 void XtensaFrameLowering::emitEpilogue(MachineFunction &MF,
                                        MachineBasicBlock &MBB) const {}
+
+// Eliminate ADJCALLSTACKDOWN, ADJCALLSTACKUP pseudo instructions
+MachineBasicBlock::iterator XtensaFrameLowering::eliminateCallFramePseudoInstr(
+    MachineFunction &MF, MachineBasicBlock &MBB,
+    MachineBasicBlock::iterator I) const {
+  const XtensaInstrInfo &TII =
+      *static_cast<const XtensaInstrInfo *>(MF.getSubtarget().getInstrInfo());
+
+  if (!hasReservedCallFrame(MF)) {
+    int64_t Amount = I->getOperand(0).getImm();
+
+    if (I->getOpcode() == Xtensa::ADJCALLSTACKDOWN)
+      Amount = -Amount;
+
+    unsigned SP = Xtensa::SP;
+    TII.adjustStackPtr(SP, Amount, MBB, I);
+  }
+
+  return MBB.erase(I);
+}
diff --git a/llvm/lib/Target/Xtensa/XtensaFrameLowering.h b/llvm/lib/Target/Xtensa/XtensaFrameLowering.h
index a5dfc83b9405..584438d179bb 100644
--- a/llvm/lib/Target/Xtensa/XtensaFrameLowering.h
+++ b/llvm/lib/Target/Xtensa/XtensaFrameLowering.h
@@ -27,6 +27,10 @@ public:
   /// the function.
   void emitPrologue(MachineFunction &, MachineBasicBlock &) const override;
   void emitEpilogue(MachineFunction &MF, MachineBasicBlock &MBB) const override;
+
+  MachineBasicBlock::iterator
+  eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
+                                MachineBasicBlock::iterator I) const override;
 };
 
 } // namespace llvm
diff --git a/llvm/lib/Target/Xtensa/XtensaISelLowering.cpp b/llvm/lib/Target/Xtensa/XtensaISelLowering.cpp
index 05d3a2524bcc..7ec459d7b2de 100644
--- a/llvm/lib/Target/Xtensa/XtensaISelLowering.cpp
+++ b/llvm/lib/Target/Xtensa/XtensaISelLowering.cpp
@@ -14,6 +14,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "XtensaISelLowering.h"
+#include "XtensaConstantPoolValue.h"
 #include "XtensaSubtarget.h"
 #include "XtensaTargetMachine.h"
 #include "llvm/CodeGen/CallingConvLower.h"
@@ -25,11 +26,20 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
+#include <deque>
 
 using namespace llvm;
 
 #define DEBUG_TYPE "xtensa-lower"
 
+// Return true if we must use long (in fact, indirect) function call.
+// It's simplified version, production implimentation must
+// resolve a functions in ROM (usually glibc functions)
+static bool isLongCall(const char *str) {
+  // Currently always use long calls
+  return true;
+}
+
 XtensaTargetLowering::XtensaTargetLowering(const TargetMachine &tm,
                                            const XtensaSubtarget &STI)
     : TargetLowering(tm), Subtarget(STI) {
@@ -137,6 +147,32 @@ CCAssignFn *XtensaTargetLowering::CCAssignFnForCall(CallingConv::ID CC,
   return CC_Xtensa_Custom;
 }
 
+// Value is a value that has been passed to us in the location described by VA
+// (and so has type VA.getLocVT()).  Convert Value to VA.getValVT(), chaining
+// any loads onto Chain.
+static SDValue convertLocVTToValVT(SelectionDAG &DAG, const SDLoc &DL,
+                                   CCValAssign &VA, SDValue Chain,
+                                   SDValue Value) {
+  // If the argument has been promoted from a smaller type, insert an
+  // assertion to capture this.
+  if (VA.getLocInfo() == CCValAssign::SExt)
+    Value = DAG.getNode(ISD::AssertSext, DL, VA.getLocVT(), Value,
+                        DAG.getValueType(VA.getValVT()));
+  else if (VA.getLocInfo() == CCValAssign::ZExt)
+    Value = DAG.getNode(ISD::AssertZext, DL, VA.getLocVT(), Value,
+                        DAG.getValueType(VA.getValVT()));
+
+  if (VA.isExtInLoc())
+    Value = DAG.getNode(ISD::TRUNCATE, DL, VA.getValVT(), Value);
+  else if (VA.getLocInfo() == CCValAssign::Indirect)
+    Value = DAG.getLoad(VA.getValVT(), DL, Chain, Value, MachinePointerInfo());
+  else if (VA.getValVT() == MVT::f32)
+    Value = DAG.getNode(ISD::BITCAST, DL, VA.getValVT(), Value);
+  else
+    assert(VA.getLocInfo() == CCValAssign::Full && "Unsupported getLocInfo");
+  return Value;
+}
+
 // Value is a value of type VA.getValVT() that we need to copy into
 // the location described by VA.  Return a copy of Value converted to
 // VA.getValVT().  The caller is responsible for handling indirect values.
@@ -250,8 +286,203 @@ SDValue XtensaTargetLowering::LowerFormalArguments(
   return Chain;
 }
 
+SDValue XtensaTargetLowering::getAddrPCRel(SDValue Op,
+                                           SelectionDAG &DAG) const {
+  SDLoc DL(Op);
+  EVT Ty = Op.getValueType();
+  return DAG.getNode(XtensaISD::PCREL_WRAPPER, DL, Ty, Op);
+}
+
+SDValue
+XtensaTargetLowering::LowerCall(CallLoweringInfo &CLI,
+                                SmallVectorImpl<SDValue> &InVals) const {
+  SelectionDAG &DAG = CLI.DAG;
+  SDLoc &DL = CLI.DL;
+  SmallVector<ISD::OutputArg, 32> &Outs = CLI.Outs;
+  SmallVector<SDValue, 32> &OutVals = CLI.OutVals;
+  SmallVector<ISD::InputArg, 32> &Ins = CLI.Ins;
+  SDValue Chain = CLI.Chain;
+  SDValue Callee = CLI.Callee;
+  bool &IsTailCall = CLI.IsTailCall;
+  CallingConv::ID CallConv = CLI.CallConv;
+  bool IsVarArg = CLI.IsVarArg;
+
+  MachineFunction &MF = DAG.getMachineFunction();
+  EVT PtrVT = getPointerTy(DAG.getDataLayout());
+  const TargetFrameLowering *TFL = Subtarget.getFrameLowering();
+
+  // TODO: Support tail call optimization.
+  IsTailCall = false;
+
+  // Analyze the operands of the call, assigning locations to each operand.
+  SmallVector<CCValAssign, 16> ArgLocs;
+  CCState CCInfo(CallConv, IsVarArg, MF, ArgLocs, *DAG.getContext());
+
+  CCAssignFn *CC = CCAssignFnForCall(CallConv, IsVarArg);
+
+  CCInfo.AnalyzeCallOperands(Outs, CC);
+
+  // Get a count of how many bytes are to be pushed on the stack.
+  unsigned NumBytes = CCInfo.getNextStackOffset();
+
+  unsigned StackAlignment = TFL->getStackAlignment();
+  unsigned NextStackOffset = alignTo(NumBytes, StackAlignment);
+
+  Chain = DAG.getCALLSEQ_START(Chain, NextStackOffset, 0, DL);
+
+  // Copy argument values to their designated locations.
+  std::deque<std::pair<unsigned, SDValue>> RegsToPass;
+  SmallVector<SDValue, 8> MemOpChains;
+  SDValue StackPtr;
+  for (unsigned I = 0, E = ArgLocs.size(); I != E; ++I) {
+    CCValAssign &VA = ArgLocs[I];
+    SDValue ArgValue = OutVals[I];
+    ISD::ArgFlagsTy Flags = Outs[I].Flags;
+
+    ArgValue = convertValVTToLocVT(DAG, DL, VA, ArgValue);
+
+    if (VA.isRegLoc())
+      // Queue up the argument copies and emit them at the end.
+      RegsToPass.push_back(std::make_pair(VA.getLocReg(), ArgValue));
+    else if (Flags.isByVal()) {
+      assert(VA.isMemLoc());
+      assert(Flags.getByValSize() &&
+             "ByVal args of size 0 should have been ignored by front-end.");
+      assert(!IsTailCall &&
+             "Do not tail-call optimize if there is a byval argument.");
+
+      if (!StackPtr.getNode())
+        StackPtr = DAG.getCopyFromReg(Chain, DL, Xtensa::SP, PtrVT);
+      unsigned Offset = VA.getLocMemOffset();
+      SDValue Address = DAG.getNode(ISD::ADD, DL, PtrVT, StackPtr,
+                                    DAG.getIntPtrConstant(Offset, DL));
+      SDValue SizeNode = DAG.getConstant(Flags.getByValSize(), DL, MVT::i32);
+      SDValue Memcpy = DAG.getMemcpy(
+          Chain, DL, Address, ArgValue, SizeNode, Flags.getNonZeroByValAlign(),
+          /*isVolatile=*/false, /*AlwaysInline=*/false,
+          /*isTailCall=*/false, MachinePointerInfo(), MachinePointerInfo());
+      MemOpChains.push_back(Memcpy);
+    } else {
+      assert(VA.isMemLoc() && "Argument not register or memory");
+
+      // Work out the address of the stack slot.  Unpromoted ints and
+      // floats are passed as right-justified 8-byte values.
+      if (!StackPtr.getNode())
+        StackPtr = DAG.getCopyFromReg(Chain, DL, Xtensa::SP, PtrVT);
+      unsigned Offset = VA.getLocMemOffset();
+      SDValue Address = DAG.getNode(ISD::ADD, DL, PtrVT, StackPtr,
+                                    DAG.getIntPtrConstant(Offset, DL));
+
+      // Emit the store.
+      MemOpChains.push_back(
+          DAG.getStore(Chain, DL, ArgValue, Address, MachinePointerInfo()));
+    }
+  }
+
+  // Join the stores, which are independent of one another.
+  if (!MemOpChains.empty())
+    Chain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other, MemOpChains);
+
+  // Build a sequence of copy-to-reg nodes, chained and glued together.
+  SDValue Glue;
+  for (unsigned I = 0, E = RegsToPass.size(); I != E; ++I) {
+    unsigned Reg = RegsToPass[I].first;
+    Chain = DAG.getCopyToReg(Chain, DL, Reg, RegsToPass[I].second, Glue);
+    Glue = Chain.getValue(1);
+  }
+
+  std::string name;
+  unsigned char TF = 0;
+
+  // Accept direct calls by converting symbolic call addresses to the
+  // associated Target* opcodes.
+  if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee)) {
+    name = E->getSymbol();
+    TF = E->getTargetFlags();
+    if (isPositionIndependent()) {
+      report_fatal_error("PIC relocations is not supported");
+    } else
+      Callee = DAG.getTargetExternalSymbol(E->getSymbol(), PtrVT, TF);
+  } else if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+    // TODO replace GlobalAddress to some special operand instead of
+    // ExternalSymbol
+    //   Callee =
+    //   DAG.getTargetExternalSymbol(strdup(G->getGlobal()->getName().str().c_str()),
+    //   PtrVT);
+
+    const GlobalValue *GV = G->getGlobal();
+    name = GV->getName().str();
+  }
+
+  if ((!name.empty()) && isLongCall(name.c_str())) {
+    // Create a constant pool entry for the callee address
+    XtensaCP::XtensaCPModifier Modifier = XtensaCP::no_modifier;
+
+    XtensaConstantPoolValue *CPV = XtensaConstantPoolSymbol::Create(
+        *DAG.getContext(), name.c_str(), 0 /* XtensaCLabelIndex */, false,
+        Modifier);
+
+    // Get the address of the callee into a register
+    SDValue CPAddr = DAG.getTargetConstantPool(CPV, PtrVT, Align(4), 0, TF);
+    SDValue CPWrap = getAddrPCRel(CPAddr, DAG);
+    Callee = CPWrap;
+  }
+
+  // The first call operand is the chain and the second is the target address.
+  SmallVector<SDValue, 8> Ops;
+  Ops.push_back(Chain);
+  Ops.push_back(Callee);
+
+  // Add a register mask operand representing the call-preserved registers.
+  const TargetRegisterInfo *TRI = Subtarget.getRegisterInfo();
+  const uint32_t *Mask = TRI->getCallPreservedMask(MF, CallConv);
+  assert(Mask && "Missing call preserved mask for calling convention");
+  Ops.push_back(DAG.getRegisterMask(Mask));
+
+  // Add argument registers to the end of the list so that they are
+  // known live into the call.
+  for (unsigned I = 0, E = RegsToPass.size(); I != E; ++I) {
+    unsigned Reg = RegsToPass[I].first;
+    Ops.push_back(DAG.getRegister(Reg, RegsToPass[I].second.getValueType()));
+  }
+
+  // Glue the call to the argument copies, if any.
+  if (Glue.getNode())
+    Ops.push_back(Glue);
+
+  SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
+  Chain = DAG.getNode(XtensaISD::CALL, DL, NodeTys, Ops);
+  Glue = Chain.getValue(1);
+
+  // Mark the end of the call, which is glued to the call itself.
+  Chain = DAG.getCALLSEQ_END(Chain, DAG.getConstant(NumBytes, DL, PtrVT, true),
+                             DAG.getConstant(0, DL, PtrVT, true), Glue, DL);
+  Glue = Chain.getValue(1);
+
+  // Assign locations to each value returned by this call.
+  SmallVector<CCValAssign, 16> RetLocs;
+  CCState RetCCInfo(CallConv, IsVarArg, MF, RetLocs, *DAG.getContext());
+  RetCCInfo.AnalyzeCallResult(Ins, RetCC_Xtensa);
+
+  // Copy all of the result registers out of their specified physreg.
+  for (unsigned I = 0, E = RetLocs.size(); I != E; ++I) {
+    CCValAssign &VA = RetLocs[I];
+
+    // Copy the value out, gluing the copy to the end of the call sequence.
+    unsigned Reg = VA.getLocReg();
+    SDValue RetValue = DAG.getCopyFromReg(Chain, DL, Reg, VA.getLocVT(), Glue);
+    Chain = RetValue.getValue(1);
+    Glue = RetValue.getValue(2);
+
+    // Convert the value of the return register into the value that's
+    // being returned.
+    InVals.push_back(convertLocVTToValVT(DAG, DL, VA, Chain, RetValue));
+  }
+  return Chain;
+}
+
 bool XtensaTargetLowering::CanLowerReturn(
-    CallingConv::ID CallConv, MachineFunction &MF, bool IsVarArg,
+    CallingConv::ID CallConv, MachineFunction & MF, bool IsVarArg,
     const SmallVectorImpl<ISD::OutputArg> &Outs, LLVMContext &Context) const {
   SmallVector<CCValAssign, 16> RVLocs;
   CCState CCInfo(CallConv, IsVarArg, MF, RVLocs, Context);
@@ -357,10 +588,9 @@ const char *XtensaTargetLowering::getTargetNodeName(unsigned Opcode) const {
   case XtensaISD::NAME:                                                        \
     return "XtensaISD::" #NAME
   switch (Opcode) {
-  case XtensaISD::FIRST_NUMBER:
-    break;
-  case XtensaISD::RET_FLAG:
-    return "XtensaISD::RET_FLAG";
+    OPCODE(RET_FLAG);
+    OPCODE(CALL);
+    OPCODE(PCREL_WRAPPER);
   }
   return NULL;
 #undef OPCODE
diff --git a/llvm/lib/Target/Xtensa/XtensaISelLowering.h b/llvm/lib/Target/Xtensa/XtensaISelLowering.h
index e2ed301e45eb..18c7772a4345 100644
--- a/llvm/lib/Target/Xtensa/XtensaISelLowering.h
+++ b/llvm/lib/Target/Xtensa/XtensaISelLowering.h
@@ -24,6 +24,16 @@ namespace llvm {
 namespace XtensaISD {
 enum {
   FIRST_NUMBER = ISD::BUILTIN_OP_END,
+
+  // Calls a function.  Operand 0 is the chain operand and operand 1
+  // is the target address.  The arguments start at operand 2.
+  // There is an optional glue operand at the end.
+  CALL,
+
+  // Wraps a TargetGlobalAddress that should be loaded using PC-relative
+  // accesses.  Operand 0 is the address.
+  PCREL_WRAPPER,
+
   // Return with a flag operand.  Operand 0 is the chain operand.
   RET_FLAG
 };
@@ -45,6 +55,8 @@ public:
                                const SmallVectorImpl<ISD::InputArg> &Ins,
                                const SDLoc &DL, SelectionDAG &DAG,
                                SmallVectorImpl<SDValue> &InVals) const override;
+  SDValue LowerCall(CallLoweringInfo &CLI,
+                    SmallVectorImpl<SDValue> &InVals) const override;
 
   bool CanLowerReturn(CallingConv::ID CallConv, MachineFunction &MF,
                       bool isVarArg,
@@ -62,6 +74,8 @@ private:
   SDValue LowerImmediate(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerImmediateFP(SDValue Op, SelectionDAG &DAG) const;
 
+  SDValue getAddrPCRel(SDValue Op, SelectionDAG &DAG) const;
+
   CCAssignFn *CCAssignFnForCall(CallingConv::ID CC, bool IsVarArg) const;
 };
 
diff --git a/llvm/lib/Target/Xtensa/XtensaInstrInfo.cpp b/llvm/lib/Target/Xtensa/XtensaInstrInfo.cpp
index 52a87fe4b934..30134c9612fd 100644
--- a/llvm/lib/Target/Xtensa/XtensaInstrInfo.cpp
+++ b/llvm/lib/Target/Xtensa/XtensaInstrInfo.cpp
@@ -15,6 +15,7 @@
 #include "XtensaInstrInfo.h"
 #include "XtensaTargetMachine.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 
@@ -23,5 +24,137 @@
 
 using namespace llvm;
 
+static inline const MachineInstrBuilder &
+addFrameReference(const MachineInstrBuilder &MIB, int FI) {
+  MachineInstr *MI = MIB;
+  MachineFunction &MF = *MI->getParent()->getParent();
+  MachineFrameInfo &MFFrame = MF.getFrameInfo();
+  const MCInstrDesc &MCID = MI->getDesc();
+  MachineMemOperand::Flags Flags = MachineMemOperand::MONone;
+  if (MCID.mayLoad())
+    Flags |= MachineMemOperand::MOLoad;
+  if (MCID.mayStore())
+    Flags |= MachineMemOperand::MOStore;
+  int64_t Offset = 0;
+  Align Alignment = MFFrame.getObjectAlign(FI);
+
+  MachineMemOperand *MMO =
+      MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(MF, FI, Offset),
+                              Flags, MFFrame.getObjectSize(FI), Alignment);
+  return MIB.addFrameIndex(FI).addImm(Offset).addMemOperand(MMO);
+}
+
 XtensaInstrInfo::XtensaInstrInfo(XtensaSubtarget &sti)
-    : XtensaGenInstrInfo(), RI(sti), STI(sti) {}
+    : XtensaGenInstrInfo(Xtensa::ADJCALLSTACKDOWN, Xtensa::ADJCALLSTACKUP), RI(sti), STI(sti) {}
+
+/// Adjust SP by Amount bytes.
+void XtensaInstrInfo::adjustStackPtr(unsigned SP, int64_t Amount,
+                                     MachineBasicBlock &MBB,
+                                     MachineBasicBlock::iterator I) const {
+  DebugLoc DL = I != MBB.end() ? I->getDebugLoc() : DebugLoc();
+
+  if (Amount == 0)
+    return;
+
+  MachineRegisterInfo &RegInfo = MBB.getParent()->getRegInfo();
+  const TargetRegisterClass *RC = &Xtensa::ARRegClass;
+
+  // create virtual reg to store immediate
+  unsigned Reg = RegInfo.createVirtualRegister(RC);
+
+  if (isInt<8>(Amount)) // addi sp, sp, amount
+    BuildMI(MBB, I, DL, get(Xtensa::ADDI), Reg).addReg(SP).addImm(Amount);
+  else { // Expand immediate that doesn't fit in 12-bit.
+    unsigned Reg1;
+    loadImmediate(MBB, I, &Reg1, Amount);
+    BuildMI(MBB, I, DL, get(Xtensa::ADD), Reg)
+        .addReg(SP)
+        .addReg(Reg1, RegState::Kill);
+  }
+
+  BuildMI(MBB, I, DL, get(Xtensa::OR), SP).addReg(Reg, RegState::Kill).addReg(Reg, RegState::Kill);
+}
+
+void XtensaInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
+                                  MachineBasicBlock::iterator MBBI,
+                                  const DebugLoc &DL, MCRegister DestReg,
+                                  MCRegister SrcReg, bool KillSrc) const {
+  // when we are copying a phys reg we want the bits for fp
+  if (Xtensa::ARRegClass.contains(DestReg, SrcReg))
+    BuildMI(MBB, MBBI, DL, get(Xtensa::OR), DestReg)
+        .addReg(SrcReg, getKillRegState(KillSrc))
+        .addReg(SrcReg, getKillRegState(KillSrc));
+  else
+    llvm_unreachable("Impossible reg-to-reg copy");
+}
+
+void XtensaInstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
+                                          MachineBasicBlock::iterator MBBI,
+                                          Register SrcReg, bool isKill,
+                                          int FrameIdx,
+                                          const TargetRegisterClass *RC,
+                                          const TargetRegisterInfo *TRI,
+                                          Register VReg) const {
+  DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+  unsigned LoadOpcode, StoreOpcode;
+  getLoadStoreOpcodes(RC, LoadOpcode, StoreOpcode, FrameIdx);
+  addFrameReference(BuildMI(MBB, MBBI, DL, get(StoreOpcode))
+                        .addReg(SrcReg, getKillRegState(isKill)),
+                    FrameIdx);
+}
+
+void XtensaInstrInfo::loadRegFromStackSlot(
+    MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, Register DestReg,
+    int FrameIdx, const TargetRegisterClass *RC,
+    const TargetRegisterInfo *TRI,
+    Register VReg) const {
+  DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+  unsigned LoadOpcode, StoreOpcode;
+  getLoadStoreOpcodes(RC, LoadOpcode, StoreOpcode, FrameIdx);
+  addFrameReference(BuildMI(MBB, MBBI, DL, get(LoadOpcode), DestReg), FrameIdx);
+}
+
+void XtensaInstrInfo::getLoadStoreOpcodes(const TargetRegisterClass *RC,
+                                          unsigned &LoadOpcode,
+                                          unsigned &StoreOpcode,
+                                          int64_t offset) const {
+  if (RC == &Xtensa::ARRegClass) {
+    LoadOpcode = Xtensa::L32I;
+    StoreOpcode = Xtensa::S32I;
+  } else
+    llvm_unreachable("Unsupported regclass to load or store");
+}
+
+void XtensaInstrInfo::loadImmediate(MachineBasicBlock &MBB,
+                                    MachineBasicBlock::iterator MBBI,
+                                    unsigned *Reg, int64_t Value) const {
+  DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+  MachineRegisterInfo &RegInfo = MBB.getParent()->getRegInfo();
+  const TargetRegisterClass *RC = &Xtensa::ARRegClass;
+
+  // create virtual reg to store immediate
+  *Reg = RegInfo.createVirtualRegister(RC);
+  if (Value >= -2048 && Value <= 2047) {
+    BuildMI(MBB, MBBI, DL, get(Xtensa::MOVI), *Reg).addImm(Value);
+  } else if (Value >= -32768 && Value <= 32767) {
+    int Low = Value & 0xFF;
+    int High = Value & ~0xFF;
+
+    BuildMI(MBB, MBBI, DL, get(Xtensa::MOVI), *Reg).addImm(Low);
+    BuildMI(MBB, MBBI, DL, get(Xtensa::ADDMI), *Reg).addReg(*Reg).addImm(High);
+  } else if (Value >= -4294967296LL && Value <= 4294967295LL) {
+    // 32 bit arbirary constant
+    MachineConstantPool *MCP = MBB.getParent()->getConstantPool();
+    uint64_t UVal = ((uint64_t)Value) & 0xFFFFFFFFLL;
+    const Constant *CVal = ConstantInt::get(
+        Type::getInt32Ty(MBB.getParent()->getFunction().getContext()), UVal,
+        false);
+    unsigned Idx = MCP->getConstantPoolIndex(CVal, Align(2U));
+    //	MCSymbol MSym
+    BuildMI(MBB, MBBI, DL, get(Xtensa::L32R), *Reg).addConstantPoolIndex(Idx);
+  } else {
+    // use L32R to let assembler load immediate best
+    // TODO replace to L32R
+    llvm_unreachable("Unsupported load immediate value");
+  }
+}
diff --git a/llvm/lib/Target/Xtensa/XtensaInstrInfo.h b/llvm/lib/Target/Xtensa/XtensaInstrInfo.h
index 7225886b2ce1..ddd5392d7ce6 100644
--- a/llvm/lib/Target/Xtensa/XtensaInstrInfo.h
+++ b/llvm/lib/Target/Xtensa/XtensaInstrInfo.h
@@ -35,8 +35,35 @@ class XtensaInstrInfo : public XtensaGenInstrInfo {
 public:
   XtensaInstrInfo(XtensaSubtarget &STI);
 
+  void adjustStackPtr(unsigned SP, int64_t Amount, MachineBasicBlock &MBB,
+                      MachineBasicBlock::iterator I) const;
+
   // Return the XtensaRegisterInfo, which this class owns.
   const XtensaRegisterInfo &getRegisterInfo() const { return RI; }
+
+  void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
+                   const DebugLoc &DL, MCRegister DestReg, MCRegister SrcReg,
+                   bool KillSrc) const override;
+  void storeRegToStackSlot(MachineBasicBlock &MBB,
+                           MachineBasicBlock::iterator MBBI, Register SrcReg,
+                           bool isKill, int FrameIndex,
+                           const TargetRegisterClass *RC,
+                           const TargetRegisterInfo *TRI,
+                           Register VReg) const override;
+  void loadRegFromStackSlot(MachineBasicBlock &MBB,
+                            MachineBasicBlock::iterator MBBI, Register DestReg,
+                            int FrameIdx, const TargetRegisterClass *RC,
+                            const TargetRegisterInfo *TRI,
+                            Register VReg) const override;
+
+  // Get the load and store opcodes for a given register class and offset.
+  void getLoadStoreOpcodes(const TargetRegisterClass *RC, unsigned &LoadOpcode,
+                           unsigned &StoreOpcode, int64_t offset) const;
+
+  // Emit code before MBBI in MI to move immediate value Value into
+  // physical register Reg.
+  void loadImmediate(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
+                     unsigned *Reg, int64_t Value) const;
 };
 } // end namespace llvm
 
diff --git a/llvm/lib/Target/Xtensa/XtensaInstrInfo.td b/llvm/lib/Target/Xtensa/XtensaInstrInfo.td
index 5a0f3f8d033d..7722f304da1a 100644
--- a/llvm/lib/Target/Xtensa/XtensaInstrInfo.td
+++ b/llvm/lib/Target/Xtensa/XtensaInstrInfo.td
@@ -239,6 +239,29 @@ def L32R : RI16_Inst<0x01, (outs AR:$t), (ins L32Rtarget:$label),
   let imm16 = label;
 }
 
+//pcrel addr loading using L32R
+def : Pat<(Xtensa_pcrel_wrapper tconstpool:$in), (L32R tconstpool:$in)>;
+
+// FrameIndexes are legalized when they are operands from load/store
+// instructions. The same not happens for stack address copies, so an
+// add op with mem ComplexPattern is used and the stack address copy
+// can be matched.
+// Setting of attribute mayLoad is trick to process instruction operands
+// in function XtensaRegisterInfo::eliminateFI
+
+let isCodeGenOnly = 1, mayLoad = 1 in {
+
+  def LEA_ADD : RRI8_Inst<0x02, (outs AR:$t), (ins mem32:$addr),
+       "addi\t$t, $addr",
+       [(set AR:$t, addr_ish4:$addr)]> {
+    bits<12> addr;
+
+    let r = 0x0C;
+    let imm8{7-0} = addr{11-4};
+    let s{3-0} = addr{3-0};
+  }
+}
+
 //===----------------------------------------------------------------------===//
 // Conditional branch instructions
 //===----------------------------------------------------------------------===//
@@ -435,6 +458,14 @@ let isReturn = 1, isTerminator = 1,
   }
 }
 
+// Call patterns
+def : Pat<(Xtensa_call (i32 tglobaladdr:$dst)),
+          (CALL0 tglobaladdr:$dst)>;
+def : Pat<(Xtensa_call (i32 texternalsym:$dst)),
+          (CALL0 texternalsym:$dst)>;
+def : Pat<(Xtensa_call AR:$dst),
+          (CALLX0 AR:$dst)>;
+
 //===----------------------------------------------------------------------===//
 // Mem barrier instructions
 //===----------------------------------------------------------------------===//
@@ -507,3 +538,19 @@ def XSR : RSR_Inst<0x00, 0x01, 0x06, (outs AR:$ard, SR:$srd), (ins AR:$t, SR:$sr
                   "xsr\t$t, $sr", []> {
   let Constraints = "$ard = $t, $srd = $sr";
 }
+
+//===----------------------------------------------------------------------===//
+// Stack allocation
+//===----------------------------------------------------------------------===//
+
+// ADJCALLSTACKDOWN/UP implicitly use/def SP because they may be expanded into
+// a stack adjustment and the codegen must know that they may modify the stack
+// pointer before prolog-epilog rewriting occurs.
+let Defs = [SP], Uses = [SP] in {
+  def ADJCALLSTACKDOWN : Pseudo<(outs), (ins i32imm:$amt1, i32imm:$amt2),
+                               "#ADJCALLSTACKDOWN",
+                               [(Xtensa_callseq_start timm:$amt1, timm:$amt2)]>;
+  def ADJCALLSTACKUP   : Pseudo<(outs), (ins i32imm:$amt1, i32imm:$amt2),
+                               "#ADJCALLSTACKUP",
+                               [(Xtensa_callseq_end timm:$amt1, timm:$amt2)]>;
+}
diff --git a/llvm/lib/Target/Xtensa/XtensaMCInstLower.cpp b/llvm/lib/Target/Xtensa/XtensaMCInstLower.cpp
index 114c562b6f4e..4688091a26bb 100644
--- a/llvm/lib/Target/Xtensa/XtensaMCInstLower.cpp
+++ b/llvm/lib/Target/Xtensa/XtensaMCInstLower.cpp
@@ -28,6 +28,54 @@ XtensaMCInstLower::XtensaMCInstLower(MCContext &ctx,
                                      XtensaAsmPrinter &asmPrinter)
     : Ctx(ctx), Printer(asmPrinter) {}
 
+MCSymbol *
+XtensaMCInstLower::GetConstantPoolIndexSymbol(const MachineOperand &MO) const {
+  // Create a symbol for the name.
+  return Printer.GetCPISymbol(MO.getIndex());
+}
+
+MCOperand
+XtensaMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
+                                      MachineOperand::MachineOperandType MOTy,
+                                      unsigned Offset) const {
+  const MCSymbol *Symbol;
+  XtensaMCExpr::VariantKind Kind = XtensaMCExpr::VK_Xtensa_None;
+
+  switch (MOTy) {
+  case MachineOperand::MO_MachineBasicBlock:
+    Symbol = MO.getMBB()->getSymbol();
+    break;
+  case MachineOperand::MO_GlobalAddress:
+    Symbol = Printer.getSymbol(MO.getGlobal());
+    Offset += MO.getOffset();
+    break;
+  case MachineOperand::MO_BlockAddress:
+    Symbol = Printer.GetBlockAddressSymbol(MO.getBlockAddress());
+    Offset += MO.getOffset();
+    break;
+  case MachineOperand::MO_ConstantPoolIndex:
+    Symbol = GetConstantPoolIndexSymbol(MO);
+    Offset += MO.getOffset();
+    break;
+  default:
+    llvm_unreachable("<unknown operand type>");
+  }
+
+  const MCExpr *ME =
+      MCSymbolRefExpr::create(Symbol, MCSymbolRefExpr::VK_None, Ctx);
+
+  ME = XtensaMCExpr::create(ME, Kind, Ctx);
+
+  if (Offset) {
+    // Assume offset is never negative.
+    assert(Offset > 0);
+
+    const MCConstantExpr *OffsetExpr = MCConstantExpr::create(Offset, Ctx);
+    ME = MCBinaryExpr::createAdd(ME, OffsetExpr, Ctx);
+  }
+
+  return MCOperand::createExpr(ME);
+}
 
 MCOperand XtensaMCInstLower::lowerOperand(const MachineOperand &MO,
                                           unsigned Offset) const {
@@ -43,6 +91,8 @@ MCOperand XtensaMCInstLower::lowerOperand(const MachineOperand &MO,
     return MCOperand::createImm(MO.getImm() + Offset);
   case MachineOperand::MO_RegisterMask:
     break;
+  case MachineOperand::MO_ConstantPoolIndex:
+    return LowerSymbolOperand(MO, MOTy, Offset);
   default:
     llvm_unreachable("unknown operand type");
   }
diff --git a/llvm/lib/Target/Xtensa/XtensaMCInstLower.h b/llvm/lib/Target/Xtensa/XtensaMCInstLower.h
index 2b238417ae3e..32a0ad86a385 100644
--- a/llvm/lib/Target/Xtensa/XtensaMCInstLower.h
+++ b/llvm/lib/Target/Xtensa/XtensaMCInstLower.h
@@ -37,6 +37,13 @@ public:
 
   // Return an MCOperand for MO.  Return an empty operand if MO is implicit.
   MCOperand lowerOperand(const MachineOperand &MO, unsigned Offset = 0) const;
+
+private:
+  MCSymbol *GetConstantPoolIndexSymbol(const MachineOperand &MO) const;
+
+  MCOperand LowerSymbolOperand(const MachineOperand &MO,
+                               MachineOperand::MachineOperandType MOTy,
+                               unsigned Offset) const;
 };
 } // end namespace llvm
 
diff --git a/llvm/lib/Target/Xtensa/XtensaOperands.td b/llvm/lib/Target/Xtensa/XtensaOperands.td
index 7a1a2e86e8c2..034aef55f763 100644
--- a/llvm/lib/Target/Xtensa/XtensaOperands.td
+++ b/llvm/lib/Target/Xtensa/XtensaOperands.td
@@ -195,7 +195,7 @@ def jumptarget : Operand<OtherVT> {
   let ParserMatchClass = XtensaPCRelTargetAsmOperand;
 }
 
-def L32Rtarget : Operand<OtherVT> {
+def L32Rtarget: Operand<i32> {
   let PrintMethod = "printL32RTarget";
   let EncoderMethod = "getL32RTargetEncoding";
   let DecoderMethod = "decodeL32ROperand";
diff --git a/llvm/lib/Target/Xtensa/XtensaOperators.td b/llvm/lib/Target/Xtensa/XtensaOperators.td
index 6b1f8e4f9b08..bb764d2c9247 100644
--- a/llvm/lib/Target/Xtensa/XtensaOperators.td
+++ b/llvm/lib/Target/Xtensa/XtensaOperators.td
@@ -8,8 +8,32 @@
 //
 //===----------------------------------------------------------------------===//
 
+//===----------------------------------------------------------------------===//
+// Type profiles
+//===----------------------------------------------------------------------===//
+
+def SDT_XtensaCallSeqStart        : SDCallSeqStart<[SDTCisVT<0, i32>, SDTCisVT<1, i32>]>;
+def SDT_XtensaCallSeqEnd          : SDCallSeqEnd<[SDTCisVT<0, i32>, SDTCisVT<1, i32>]>;
+def SDT_XtensaCall                : SDTypeProfile<0, -1, [SDTCisPtrTy<0>]>;
+def SDT_XtensaWrapPtr             : SDTypeProfile<1, 1,
+                                                 [SDTCisSameAs<0, 1>,
+                                                  SDTCisPtrTy<0>]>;
+
 //===----------------------------------------------------------------------===//
 // Node definitions
 //===----------------------------------------------------------------------===//
+
+def Xtensa_call: SDNode<"XtensaISD::CALL", SDT_XtensaCall,
+                       [SDNPHasChain, SDNPOutGlue, SDNPOptInGlue, SDNPVariadic]>;
+
 def Xtensa_retflag: SDNode<"XtensaISD::RET_FLAG", SDTNone,
-                                 [SDNPHasChain, SDNPOptInGlue, SDNPVariadic]>;
+                          [SDNPHasChain, SDNPOptInGlue, SDNPVariadic]>;
+
+
+def Xtensa_callseq_start: SDNode<"ISD::CALLSEQ_START", SDT_XtensaCallSeqStart,
+                                [SDNPHasChain, SDNPSideEffect, SDNPOutGlue]>;
+def Xtensa_callseq_end  : SDNode<"ISD::CALLSEQ_END",   SDT_XtensaCallSeqEnd,
+                                [SDNPHasChain, SDNPSideEffect, SDNPOptInGlue,
+                                 SDNPOutGlue]>;
+
+def Xtensa_pcrel_wrapper: SDNode<"XtensaISD::PCREL_WRAPPER", SDT_XtensaWrapPtr, []>;
diff --git a/llvm/lib/Target/Xtensa/XtensaRegisterInfo.cpp b/llvm/lib/Target/Xtensa/XtensaRegisterInfo.cpp
index 5cebe4a3346b..559443f07fbb 100644
--- a/llvm/lib/Target/Xtensa/XtensaRegisterInfo.cpp
+++ b/llvm/lib/Target/Xtensa/XtensaRegisterInfo.cpp
@@ -15,6 +15,7 @@
 #include "XtensaRegisterInfo.h"
 #include "XtensaInstrInfo.h"
 #include "XtensaSubtarget.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/Support/Debug.h"
@@ -57,11 +58,117 @@ BitVector XtensaRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   return Reserved;
 }
 
+bool XtensaRegisterInfo::eliminateFI(MachineBasicBlock::iterator II,
+                                     unsigned OpNo, int FrameIndex,
+                                     uint64_t StackSize,
+                                     int64_t SPOffset) const {
+  MachineInstr &MI = *II;
+  MachineFunction &MF = *MI.getParent()->getParent();
+  MachineFrameInfo &MFI = MF.getFrameInfo();
+
+  const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();
+  int MinCSFI = 0;
+  int MaxCSFI = -1;
+
+  if (CSI.size()) {
+    MinCSFI = CSI[0].getFrameIdx();
+    MaxCSFI = CSI[CSI.size() - 1].getFrameIdx();
+  }
+
+  // The following stack frame objects are always referenced relative to $sp:
+  //  1. Outgoing arguments.
+  //  2. Pointer to dynamically allocated stack space.
+  //  3. Locations for callee-saved registers.
+  //  4. Locations for eh data registers.
+  // Everything else is referenced relative to whatever register
+  // getFrameRegister() returns.
+  unsigned FrameReg;
+
+  if ((FrameIndex >= MinCSFI && FrameIndex <= MaxCSFI))
+    FrameReg = Xtensa::SP;
+  else
+    FrameReg = getFrameRegister(MF);
+
+  // Calculate final offset.
+  // - There is no need to change the offset if the frame object is one of the
+  //   following: an outgoing argument, pointer to a dynamically allocated
+  //   stack space or a $gp restore location,
+  // - If the frame object is any of the following, its offset must be adjusted
+  //   by adding the size of the stack:
+  //   incoming argument, callee-saved register location or local variable.
+  bool IsKill = false;
+  int64_t Offset;
+
+  Offset = SPOffset + (int64_t)StackSize;
+  Offset += MI.getOperand(OpNo + 1).getImm();
+
+  LLVM_DEBUG(errs() << "Offset     : " << Offset << "\n"
+                    << "<--------->\n");
+
+  bool Valid = false;
+  switch (MI.getOpcode()) {
+  case Xtensa::L8UI:
+  case Xtensa::S8I:
+    Valid = (Offset >= 0 && Offset <= 255);
+    break;
+  case Xtensa::L16SI:
+  case Xtensa::L16UI:
+  case Xtensa::S16I:
+    Valid = (Offset >= 0 && Offset <= 510);
+    break;
+  case Xtensa::LEA_ADD:
+    Valid = (Offset >= -128 && Offset <= 127);
+    break;
+  default:
+    Valid = (Offset >= 0 && Offset <= 1020);
+    break;
+  }
+
+  // If MI is not a debug value, make sure Offset fits in the 16-bit immediate
+  // field.
+  if (!MI.isDebugValue() && !Valid) {
+    MachineBasicBlock &MBB = *MI.getParent();
+    DebugLoc DL = II->getDebugLoc();
+    unsigned ADD = Xtensa::ADD;
+    unsigned Reg;
+    const XtensaInstrInfo &TII = *static_cast<const XtensaInstrInfo *>(
+        MBB.getParent()->getSubtarget().getInstrInfo());
+
+    TII.loadImmediate(MBB, II, &Reg, Offset);
+    BuildMI(MBB, II, DL, TII.get(ADD), Reg)
+        .addReg(FrameReg)
+        .addReg(Reg, RegState::Kill);
+
+    FrameReg = Reg;
+    Offset = 0;
+    IsKill = true;
+  }
+
+  MI.getOperand(OpNo).ChangeToRegister(FrameReg, false, false, IsKill);
+  MI.getOperand(OpNo + 1).ChangeToImmediate(Offset);
+
+  return false;
+}
+
 bool XtensaRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
                                              int SPAdj, unsigned FIOperandNum,
                                              RegScavenger *RS) const {
-  report_fatal_error("Eliminate frame index not supported yet");
-  return false;
+  MachineInstr &MI = *II;
+  MachineFunction &MF = *MI.getParent()->getParent();
+
+  LLVM_DEBUG(errs() << "\nFunction : " << MF.getName() << "\n";
+             errs() << "<--------->\n"
+                    << MI);
+
+  int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
+  uint64_t stackSize = MF.getFrameInfo().getStackSize();
+  int64_t spOffset = MF.getFrameInfo().getObjectOffset(FrameIndex);
+
+  LLVM_DEBUG(errs() << "FrameIndex : " << FrameIndex << "\n"
+                    << "spOffset   : " << spOffset << "\n"
+                    << "stackSize  : " << stackSize << "\n");
+
+  return eliminateFI(MI, FIOperandNum, FrameIndex, stackSize, spOffset);
 }
 
 Register XtensaRegisterInfo::getFrameRegister(const MachineFunction &MF) const {
diff --git a/llvm/lib/Target/Xtensa/XtensaRegisterInfo.h b/llvm/lib/Target/Xtensa/XtensaRegisterInfo.h
index 4f5426acf7a5..ba5557c446b6 100644
--- a/llvm/lib/Target/Xtensa/XtensaRegisterInfo.h
+++ b/llvm/lib/Target/Xtensa/XtensaRegisterInfo.h
@@ -49,6 +49,11 @@ public:
                            unsigned FIOperandNum,
                            RegScavenger *RS = nullptr) const override;
   Register getFrameRegister(const MachineFunction &MF) const override;
+
+private:
+  bool eliminateFI(MachineBasicBlock::iterator II, unsigned OpNo,
+                   int FrameIndex, uint64_t StackSize,
+                   int64_t SPOffset) const;
 };
 
 } // end namespace llvm
-- 
2.40.1