Let me introduce you to the early stages of the llvm backend for the alpha processor

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19764 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 268 insertions, 0 deletions

diff --git a/lib/Target/Alpha/AlphaRegisterInfo.cpp b/lib/Target/Alpha/AlphaRegisterInfo.cpp
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+++ b/lib/Target/Alpha/AlphaRegisterInfo.cpp
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+//===- PPC64RegisterInfo.cpp - PowerPC64 Register Information ---*- C++ -*-===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file contains the PowerPC64 implementation of the MRegisterInfo class.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "reginfo"
+#include "Alpha.h"
+#include "AlphaInstrBuilder.h"
+#include "AlphaRegisterInfo.h"
+#include "llvm/Constants.h"
+#include "llvm/Type.h"
+#include "llvm/CodeGen/ValueTypes.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/Target/TargetFrameInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/STLExtras.h"
+#include <cstdlib>
+#include <iostream>
+using namespace llvm;
+
+
+AlphaRegisterInfo::AlphaRegisterInfo()
+  : AlphaGenRegisterInfo(Alpha::ADJUSTSTACKDOWN, Alpha::ADJUSTSTACKUP)
+{
+}
+
+static const TargetRegisterClass *getClass(unsigned SrcReg) {
+  if (Alpha::FPRCRegisterClass->contains(SrcReg))
+    return Alpha::FPRCRegisterClass;
+  assert(Alpha::GPRCRegisterClass->contains(SrcReg) && "Reg not FPR or GPR");
+  return Alpha::GPRCRegisterClass;
+}
+
+void 
+AlphaRegisterInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
+                                       MachineBasicBlock::iterator MI,
+                                       unsigned SrcReg, int FrameIdx) const {
+  std::cerr << "Trying to store " << getPrettyName(SrcReg) << " to " << FrameIdx << "\n";
+  //BuildMI(MBB, MI, Alpha::WTF, 0).addReg(SrcReg);
+  BuildMI(MBB, MI, Alpha::STQ, 3).addReg(SrcReg).addImm(FrameIdx * 8).addReg(Alpha::R30);
+  //  assert(0 && "TODO");
+}
+
+void
+AlphaRegisterInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
+                                        MachineBasicBlock::iterator MI,
+                                        unsigned DestReg, int FrameIdx) const{
+  std::cerr << "Trying to load " << getPrettyName(DestReg) << " to " << FrameIdx << "\n";
+  //BuildMI(MBB, MI, Alpha::WTF, 0, DestReg);
+  BuildMI(MBB, MI, Alpha::LDQ, 2, DestReg).addImm(FrameIdx * 8).addReg(Alpha::R30);
+  //  assert(0 && "TODO");
+}
+
+void AlphaRegisterInfo::copyRegToReg(MachineBasicBlock &MBB,
+                                     MachineBasicBlock::iterator MI,
+                                     unsigned DestReg, unsigned SrcReg,
+                                     const TargetRegisterClass *RC) const {
+  //  std::cerr << "copyRegToReg " << DestReg << " <- " << SrcReg << "\n";
+  if (RC == Alpha::GPRCRegisterClass) {
+    BuildMI(MBB, MI, Alpha::BIS, 2, DestReg).addReg(SrcReg).addReg(SrcReg);
+//   } else if (RC == Alpha::FPRCRegisterClass) {
+//     BuildMI(MBB, MI, PPC::FMR, 1, DestReg).addReg(SrcReg);
+  } else { 
+    std::cerr << "Attempt to copy register that is not GPR or FPR";
+     abort();
+  }
+}
+
+//===----------------------------------------------------------------------===//
+// Stack Frame Processing methods
+//===----------------------------------------------------------------------===//
+
+// hasFP - Return true if the specified function should have a dedicated frame
+// pointer register.  This is true if the function has variable sized allocas or
+// if frame pointer elimination is disabled.
+//
+static bool hasFP(MachineFunction &MF) {
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  return MFI->hasVarSizedObjects();
+}
+
+void AlphaRegisterInfo::
+eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
+                              MachineBasicBlock::iterator I) const {
+  if (hasFP(MF)) {
+    assert(0 && "TODO");
+    // If we have a frame pointer, turn the adjcallstackup instruction into a
+    // 'sub ESP, <amt>' and the adjcallstackdown instruction into 'add ESP,
+    // <amt>'
+    MachineInstr *Old = I;
+    unsigned Amount = Old->getOperand(0).getImmedValue();
+    if (Amount != 0) {
+      // We need to keep the stack aligned properly.  To do this, we round the
+      // amount of space needed for the outgoing arguments up to the next
+      // alignment boundary.
+      unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
+      Amount = (Amount+Align-1)/Align*Align;
+
+      MachineInstr *New;
+//       if (Old->getOpcode() == X86::ADJCALLSTACKDOWN) {
+// 	New=BuildMI(X86::SUB32ri, 1, X86::ESP, MachineOperand::UseAndDef)
+//               .addZImm(Amount);
+//       } else {
+// 	assert(Old->getOpcode() == X86::ADJCALLSTACKUP);
+// 	New=BuildMI(X86::ADD32ri, 1, X86::ESP, MachineOperand::UseAndDef)
+//               .addZImm(Amount);
+//       }
+
+      // Replace the pseudo instruction with a new instruction...
+      MBB.insert(I, New);
+    }
+  }
+
+  MBB.erase(I);
+}
+
+void
+AlphaRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II) const {
+  assert(0 && "TODO");
+//   unsigned i = 0;
+//   MachineInstr &MI = *II;
+//   MachineBasicBlock &MBB = *MI.getParent();
+//   MachineFunction &MF = *MBB.getParent();
+  
+//   while (!MI.getOperand(i).isFrameIndex()) {
+//     ++i;
+//     assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
+//   }
+
+//   int FrameIndex = MI.getOperand(i).getFrameIndex();
+
+//   // Replace the FrameIndex with base register with GPR1 (SP) or GPR31 (FP).
+//   MI.SetMachineOperandReg(i, hasFP(MF) ? PPC::R31 : PPC::R1);
+
+//   // Take into account whether it's an add or mem instruction
+//   unsigned OffIdx = (i == 2) ? 1 : 2;
+
+//   // Now add the frame object offset to the offset from r1.
+//   int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
+//                MI.getOperand(OffIdx).getImmedValue();
+
+//   // If we're not using a Frame Pointer that has been set to the value of the
+//   // SP before having the stack size subtracted from it, then add the stack size
+//   // to Offset to get the correct offset.
+//   Offset += MF.getFrameInfo()->getStackSize();
+  
+//   if (Offset > 32767 || Offset < -32768) {
+//     // Insert a set of r0 with the full offset value before the ld, st, or add
+//     MachineBasicBlock *MBB = MI.getParent();
+//     MBB->insert(II, BuildMI(PPC::LIS, 1, PPC::R0).addSImm(Offset >> 16));
+//     MBB->insert(II, BuildMI(PPC::ORI, 2, PPC::R0).addReg(PPC::R0)
+//       .addImm(Offset));
+//     // convert into indexed form of the instruction
+//     // sth 0:rA, 1:imm 2:(rB) ==> sthx 0:rA, 2:rB, 1:r0
+//     // addi 0:rA 1:rB, 2, imm ==> add 0:rA, 1:rB, 2:r0
+//     unsigned NewOpcode = 
+//       const_cast<std::map<unsigned, unsigned>& >(ImmToIdxMap)[MI.getOpcode()];
+//     assert(NewOpcode && "No indexed form of load or store available!");
+//     MI.setOpcode(NewOpcode);
+//     MI.SetMachineOperandReg(1, MI.getOperand(i).getReg());
+//     MI.SetMachineOperandReg(2, PPC::R0);
+//   } else {
+//     MI.SetMachineOperandConst(OffIdx, MachineOperand::MO_SignExtendedImmed,
+//                               Offset);
+//   }
+}
+
+
+void AlphaRegisterInfo::emitPrologue(MachineFunction &MF) const {
+  MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
+  MachineBasicBlock::iterator MBBI = MBB.begin();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  MachineInstr *MI;
+  
+  //handle GOP offset
+  MI = BuildMI(Alpha::LDGP, 0);
+  MBB.insert(MBBI, MI);
+
+  // Get the number of bytes to allocate from the FrameInfo
+  unsigned NumBytes = MFI->getStackSize();
+
+  // Do we need to allocate space on the stack?
+  if (NumBytes == 0) return;
+
+  // Add the size of R30 to  NumBytes size for the store of R30 to the 
+  // stack
+//   std::cerr << "Spillsize of R30 is " << getSpillSize(Alpha::R30) << "\n";
+//   NumBytes = NumBytes + getSpillSize(Alpha::R30)/8;
+
+  // Update frame info to pretend that this is part of the stack...
+  MFI->setStackSize(NumBytes);
+  
+  // adjust stack pointer: r30 -= numbytes
+  
+  if (NumBytes <= 32000) //FIXME: do this better 
+    {
+      MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(-NumBytes).addReg(Alpha::R30);
+      MBB.insert(MBBI, MI);
+    } else {
+      std::cerr << "Too big a stack frame\n";
+      abort();
+    }
+}
+
+void AlphaRegisterInfo::emitEpilogue(MachineFunction &MF,
+                                     MachineBasicBlock &MBB) const {
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineInstr *MI;
+  assert((MBBI->getOpcode() == Alpha::RET || MBBI->getOpcode() == Alpha::RETURN) &&
+	 "Can only insert epilog into returning blocks");
+  
+  // Get the number of bytes allocated from the FrameInfo...
+  unsigned NumBytes = MFI->getStackSize();
+
+   if (NumBytes != 0) 
+     {
+       if (NumBytes <= 32000) //FIXME: do this better 
+	 {
+	   MI=BuildMI(Alpha::LDA, 2, Alpha::R30).addImm(NumBytes).addReg(Alpha::R30);
+	   MBB.insert(MBBI, MI);
+	 } else {
+	   std::cerr << "Too big a stack frame\n";
+	   abort();
+	 }
+     }
+}
+
+#include "AlphaGenRegisterInfo.inc"
+
+const TargetRegisterClass*
+AlphaRegisterInfo::getRegClassForType(const Type* Ty) const {
+  switch (Ty->getTypeID()) {
+    default:              assert(0 && "Invalid type to getClass!");
+    case Type::BoolTyID:
+    case Type::SByteTyID:
+    case Type::UByteTyID:
+    case Type::ShortTyID:
+    case Type::UShortTyID:
+    case Type::IntTyID:
+    case Type::UIntTyID:
+    case Type::PointerTyID:
+    case Type::LongTyID:
+    case Type::ULongTyID:  return &GPRCInstance;
+     
+  case Type::FloatTyID:
+  case Type::DoubleTyID: return &FPRCInstance;
+  }
+}
+
+std::string AlphaRegisterInfo::getPrettyName(unsigned reg)
+{
+  std::string s(RegisterDescriptors[reg].Name);
+  return s;
+}