Rename TargetFrameInfo into TargetFrameLowering. Also, put couple of FIXMEs and fixes here and there.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123170 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 450 insertions, 0 deletions

diff --git a/lib/Target/MBlaze/MBlazeFrameLowering.cpp b/lib/Target/MBlaze/MBlazeFrameLowering.cpp
new file mode 100644
index 0000000000..9cd8d9d145
--- /dev/null
+++ b/lib/Target/MBlaze/MBlazeFrameLowering.cpp
@@ -0,0 +1,450 @@
+//=======- MBlazeFrameLowering.cpp - MBlaze Frame Information ------*- C++ -*-====//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the MBlaze implementation of TargetFrameLowering class.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "mblaze-frame-lowering"
+
+#include "MBlazeFrameLowering.h"
+#include "MBlazeInstrInfo.h"
+#include "MBlazeMachineFunction.h"
+#include "InstPrinter/MBlazeInstPrinter.h"
+#include "llvm/Function.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetOptions.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace llvm {
+  cl::opt<bool> DisableStackAdjust(
+    "disable-mblaze-stack-adjust",
+    cl::init(false),
+    cl::desc("Disable MBlaze stack layout adjustment."),
+    cl::Hidden);
+}
+
+static void replaceFrameIndexes(MachineFunction &MF, 
+                                SmallVector<std::pair<int,int64_t>, 16> &FR) {
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
+  const SmallVector<std::pair<int,int64_t>, 16>::iterator FRB = FR.begin();
+  const SmallVector<std::pair<int,int64_t>, 16>::iterator FRE = FR.end();
+
+  SmallVector<std::pair<int,int64_t>, 16>::iterator FRI = FRB;
+  for (; FRI != FRE; ++FRI) {
+    MFI->RemoveStackObject(FRI->first);
+    int NFI = MFI->CreateFixedObject(4, FRI->second, true);
+    MBlazeFI->recordReplacement(FRI->first, NFI);
+
+    for (MachineFunction::iterator MB=MF.begin(), ME=MF.end(); MB!=ME; ++MB) {
+      MachineBasicBlock::iterator MBB = MB->begin();
+      const MachineBasicBlock::iterator MBE = MB->end();
+
+      for (; MBB != MBE; ++MBB) {
+        MachineInstr::mop_iterator MIB = MBB->operands_begin();
+        const MachineInstr::mop_iterator MIE = MBB->operands_end();
+
+        for (MachineInstr::mop_iterator MII = MIB; MII != MIE; ++MII) {
+          if (!MII->isFI() || MII->getIndex() != FRI->first) continue;
+          DEBUG(dbgs() << "FOUND FI#" << MII->getIndex() << "\n");
+          MII->setIndex(NFI);
+        }
+      }
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
+//
+// Stack Frame Processing methods
+// +----------------------------+
+//
+// The stack is allocated decrementing the stack pointer on
+// the first instruction of a function prologue. Once decremented,
+// all stack references are are done through a positive offset
+// from the stack/frame pointer, so the stack is considered
+// to grow up.
+//
+//===----------------------------------------------------------------------===//
+
+static void analyzeFrameIndexes(MachineFunction &MF) {
+  if (DisableStackAdjust) return;
+
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
+  const MachineRegisterInfo &MRI = MF.getRegInfo();
+
+  MachineRegisterInfo::livein_iterator LII = MRI.livein_begin();
+  MachineRegisterInfo::livein_iterator LIE = MRI.livein_end();
+  const SmallVector<int, 16> &LiveInFI = MBlazeFI->getLiveIn();
+  SmallVector<MachineInstr*, 16> EraseInstr;
+  SmallVector<std::pair<int,int64_t>, 16> FrameRelocate;
+
+  MachineBasicBlock *MBB = MF.getBlockNumbered(0);
+  MachineBasicBlock::iterator MIB = MBB->begin();
+  MachineBasicBlock::iterator MIE = MBB->end();
+
+  int StackAdjust = 0;
+  int StackOffset = -28;
+
+  // In this loop we are searching frame indexes that corrospond to incoming
+  // arguments that are already in the stack. We look for instruction sequences
+  // like the following:
+  //    
+  //    LWI REG, FI1, 0
+  //    ...
+  //    SWI REG, FI2, 0
+  //
+  // As long as there are no defs of REG in the ... part, we can eliminate
+  // the SWI instruction because the value has already been stored to the
+  // stack by the caller. All we need to do is locate FI at the correct
+  // stack location according to the calling convensions.
+  //
+  // Additionally, if the SWI operation kills the def of REG then we don't
+  // need the LWI operation so we can erase it as well.
+  for (unsigned i = 0, e = LiveInFI.size(); i < e; ++i) {
+    for (MachineBasicBlock::iterator I=MIB; I != MIE; ++I) {
+      if (I->getOpcode() != MBlaze::LWI || I->getNumOperands() != 3 ||
+          !I->getOperand(1).isFI() || !I->getOperand(0).isReg() ||
+          I->getOperand(1).getIndex() != LiveInFI[i]) continue;
+
+      unsigned FIReg = I->getOperand(0).getReg();
+      MachineBasicBlock::iterator SI = I;
+      for (SI++; SI != MIE; ++SI) {
+        if (!SI->getOperand(0).isReg() ||
+            !SI->getOperand(1).isFI() ||
+            SI->getOpcode() != MBlaze::SWI) continue;
+
+        int FI = SI->getOperand(1).getIndex();
+        if (SI->getOperand(0).getReg() != FIReg ||
+            MFI->isFixedObjectIndex(FI) ||
+            MFI->getObjectSize(FI) != 4) continue;
+
+        if (SI->getOperand(0).isDef()) break;
+
+        if (SI->getOperand(0).isKill()) {
+          DEBUG(dbgs() << "LWI for FI#" << I->getOperand(1).getIndex() 
+                       << " removed\n");
+          EraseInstr.push_back(I);
+        }
+
+        EraseInstr.push_back(SI);
+        DEBUG(dbgs() << "SWI for FI#" << FI << " removed\n");
+
+        FrameRelocate.push_back(std::make_pair(FI,StackOffset));
+        DEBUG(dbgs() << "FI#" << FI << " relocated to " << StackOffset << "\n");
+
+        StackOffset -= 4;
+        StackAdjust += 4;
+        break;
+      }
+    }
+  }
+
+  // In this loop we are searching for frame indexes that corrospond to
+  // incoming arguments that are in registers. We look for instruction
+  // sequences like the following:
+  //    
+  //    ...  SWI REG, FI, 0
+  // 
+  // As long as the ... part does not define REG and if REG is an incoming
+  // parameter register then we know that, according to ABI convensions, the
+  // caller has allocated stack space for it already.  Instead of allocating
+  // stack space on our frame, we record the correct location in the callers
+  // frame.
+  for (MachineRegisterInfo::livein_iterator LI = LII; LI != LIE; ++LI) {
+    for (MachineBasicBlock::iterator I=MIB; I != MIE; ++I) {
+      if (I->definesRegister(LI->first))
+        break;
+
+      if (I->getOpcode() != MBlaze::SWI || I->getNumOperands() != 3 ||
+          !I->getOperand(1).isFI() || !I->getOperand(0).isReg() ||
+          I->getOperand(1).getIndex() < 0) continue;
+
+      if (I->getOperand(0).getReg() == LI->first) {
+        int FI = I->getOperand(1).getIndex();
+        MBlazeFI->recordLiveIn(FI);
+
+        int FILoc = 0;
+        switch (LI->first) {
+        default: llvm_unreachable("invalid incoming parameter!");
+        case MBlaze::R5:  FILoc = -4; break;
+        case MBlaze::R6:  FILoc = -8; break;
+        case MBlaze::R7:  FILoc = -12; break;
+        case MBlaze::R8:  FILoc = -16; break;
+        case MBlaze::R9:  FILoc = -20; break;
+        case MBlaze::R10: FILoc = -24; break;
+        }
+
+        StackAdjust += 4;
+        FrameRelocate.push_back(std::make_pair(FI,FILoc));
+        DEBUG(dbgs() << "FI#" << FI << " relocated to " << FILoc << "\n");
+        break;
+      }
+    }
+  }
+
+  // Go ahead and erase all of the instructions that we determined were
+  // no longer needed.
+  for (int i = 0, e = EraseInstr.size(); i < e; ++i)
+    MBB->erase(EraseInstr[i]);
+
+  // Replace all of the frame indexes that we have relocated with new
+  // fixed object frame indexes.
+  replaceFrameIndexes(MF, FrameRelocate);
+}
+
+static void interruptFrameLayout(MachineFunction &MF) {
+  const Function *F = MF.getFunction();
+  llvm::CallingConv::ID CallConv = F->getCallingConv();
+
+  // If this function is not using either the interrupt_handler
+  // calling convention or the save_volatiles calling convention
+  // then we don't need to do any additional frame layout.
+  if (CallConv != llvm::CallingConv::MBLAZE_INTR &&
+      CallConv != llvm::CallingConv::MBLAZE_SVOL)
+      return;
+
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  const MachineRegisterInfo &MRI = MF.getRegInfo();
+  const MBlazeInstrInfo &TII =
+    *static_cast<const MBlazeInstrInfo*>(MF.getTarget().getInstrInfo());
+
+  // Determine if the calling convention is the interrupt_handler
+  // calling convention. Some pieces of the prologue and epilogue
+  // only need to be emitted if we are lowering and interrupt handler.
+  bool isIntr = CallConv == llvm::CallingConv::MBLAZE_INTR;
+
+  // Determine where to put prologue and epilogue additions
+  MachineBasicBlock &MENT   = MF.front();
+  MachineBasicBlock &MEXT   = MF.back();
+
+  MachineBasicBlock::iterator MENTI = MENT.begin();
+  MachineBasicBlock::iterator MEXTI = prior(MEXT.end());
+
+  DebugLoc ENTDL = MENTI != MENT.end() ? MENTI->getDebugLoc() : DebugLoc();
+  DebugLoc EXTDL = MEXTI != MEXT.end() ? MEXTI->getDebugLoc() : DebugLoc();
+
+  // Store the frame indexes generated during prologue additions for use
+  // when we are generating the epilogue additions.
+  SmallVector<int, 10> VFI;
+
+  // Build the prologue SWI for R3 - R12 if needed. Note that R11 must
+  // always have a SWI because it is used when processing RMSR.
+  for (unsigned r = MBlaze::R3; r <= MBlaze::R12; ++r) {
+    if (!MRI.isPhysRegUsed(r) && !(isIntr && r == MBlaze::R11)) continue;
+    
+    int FI = MFI->CreateStackObject(4,4,false,false);
+    VFI.push_back(FI);
+
+    BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), r)
+      .addFrameIndex(FI).addImm(0);
+  }
+    
+  // Build the prologue SWI for R17, R18
+  int R17FI = MFI->CreateStackObject(4,4,false,false);
+  int R18FI = MFI->CreateStackObject(4,4,false,false);
+
+  BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R17)
+    .addFrameIndex(R17FI).addImm(0);
+    
+  BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R18)
+    .addFrameIndex(R18FI).addImm(0);
+
+  // Buid the prologue SWI and the epilogue LWI for RMSR if needed
+  if (isIntr) {
+    int MSRFI = MFI->CreateStackObject(4,4,false,false);
+    BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::MFS), MBlaze::R11)
+      .addReg(MBlaze::RMSR);
+    BuildMI(MENT, MENTI, ENTDL, TII.get(MBlaze::SWI), MBlaze::R11)
+      .addFrameIndex(MSRFI).addImm(0);
+
+    BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R11)
+      .addFrameIndex(MSRFI).addImm(0);
+    BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::MTS), MBlaze::RMSR)
+      .addReg(MBlaze::R11);
+  }
+
+  // Build the epilogue LWI for R17, R18
+  BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R18)
+    .addFrameIndex(R18FI).addImm(0);
+
+  BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), MBlaze::R17)
+    .addFrameIndex(R17FI).addImm(0);
+
+  // Build the epilogue LWI for R3 - R12 if needed
+  for (unsigned r = MBlaze::R12, i = VFI.size(); r >= MBlaze::R3; --r) {
+    if (!MRI.isPhysRegUsed(r)) continue;
+    BuildMI(MEXT, MEXTI, EXTDL, TII.get(MBlaze::LWI), r)
+      .addFrameIndex(VFI[--i]).addImm(0);
+  }
+}
+
+static void determineFrameLayout(MachineFunction &MF) {
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
+
+  // Replace the dummy '0' SPOffset by the negative offsets, as explained on
+  // LowerFORMAL_ARGUMENTS. Leaving '0' for while is necessary to avoid
+  // the approach done by calculateFrameObjectOffsets to the stack frame.
+  MBlazeFI->adjustLoadArgsFI(MFI);
+  MBlazeFI->adjustStoreVarArgsFI(MFI);
+
+  // Get the number of bytes to allocate from the FrameInfo
+  unsigned FrameSize = MFI->getStackSize();
+  DEBUG(dbgs() << "Original Frame Size: " << FrameSize << "\n" );
+
+  // Get the alignments provided by the target, and the maximum alignment
+  // (if any) of the fixed frame objects.
+  // unsigned MaxAlign = MFI->getMaxAlignment();
+  unsigned TargetAlign = MF.getTarget().getFrameLowering()->getStackAlignment();
+  unsigned AlignMask = TargetAlign - 1;
+
+  // Make sure the frame is aligned.
+  FrameSize = (FrameSize + AlignMask) & ~AlignMask;
+  MFI->setStackSize(FrameSize);
+  DEBUG(dbgs() << "Aligned Frame Size: " << FrameSize << "\n" );
+}
+
+int MBlazeFrameInfo::getFrameIndexOffset(const MachineFunction &MF, int FI) 
+  const {
+  const MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
+  if (MBlazeFI->hasReplacement(FI))
+    FI = MBlazeFI->getReplacement(FI);
+  return TargetFrameInfo::getFrameIndexOffset(MF,FI);
+}
+
+// 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.
+bool MBlazeFrameLowering::hasFP(const MachineFunction &MF) const {
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  return DisableFramePointerElim(MF) || MFI->hasVarSizedObjects();
+}
+
+void MBlazeFrameLowering::emitPrologue(MachineFunction &MF) const {
+  MachineBasicBlock &MBB   = MF.front();
+  MachineFrameInfo *MFI    = MF.getFrameInfo();
+  const MBlazeInstrInfo &TII =
+    *static_cast<const MBlazeInstrInfo*>(MF.getTarget().getInstrInfo());
+  MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
+  MachineBasicBlock::iterator MBBI = MBB.begin();
+  DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+
+  llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
+  bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
+
+  // Determine the correct frame layout
+  determineFrameLayout(MF);
+
+  // Get the number of bytes to allocate from the FrameInfo.
+  unsigned StackSize = MFI->getStackSize();
+
+  // No need to allocate space on the stack.
+  if (StackSize == 0 && !MFI->adjustsStack() && !requiresRA) return;
+
+  int FPOffset = MBlazeFI->getFPStackOffset();
+  int RAOffset = MBlazeFI->getRAStackOffset();
+
+  // Adjust stack : addi R1, R1, -imm
+  BuildMI(MBB, MBBI, DL, TII.get(MBlaze::ADDIK), MBlaze::R1)
+      .addReg(MBlaze::R1).addImm(-StackSize);
+
+  // swi  R15, R1, stack_loc
+  if (MFI->adjustsStack() || requiresRA) {
+    BuildMI(MBB, MBBI, DL, TII.get(MBlaze::SWI))
+        .addReg(MBlaze::R15).addReg(MBlaze::R1).addImm(RAOffset);
+  }
+
+  if (hasFP(MF)) {
+    // swi  R19, R1, stack_loc
+    BuildMI(MBB, MBBI, DL, TII.get(MBlaze::SWI))
+      .addReg(MBlaze::R19).addReg(MBlaze::R1).addImm(FPOffset);
+
+    // add R19, R1, R0
+    BuildMI(MBB, MBBI, DL, TII.get(MBlaze::ADD), MBlaze::R19)
+      .addReg(MBlaze::R1).addReg(MBlaze::R0);
+  }
+}
+
+void MBlazeFrameLowering::emitEpilogue(MachineFunction &MF,
+                                   MachineBasicBlock &MBB) const {
+  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  MachineFrameInfo *MFI            = MF.getFrameInfo();
+  MBlazeFunctionInfo *MBlazeFI     = MF.getInfo<MBlazeFunctionInfo>();
+  const MBlazeInstrInfo &TII =
+    *static_cast<const MBlazeInstrInfo*>(MF.getTarget().getInstrInfo());
+
+  DebugLoc dl = MBBI->getDebugLoc();
+
+  llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
+  bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
+
+  // Get the FI's where RA and FP are saved.
+  int FPOffset = MBlazeFI->getFPStackOffset();
+  int RAOffset = MBlazeFI->getRAStackOffset();
+
+  if (hasFP(MF)) {
+    // add R1, R19, R0
+    BuildMI(MBB, MBBI, dl, TII.get(MBlaze::ADD), MBlaze::R1)
+      .addReg(MBlaze::R19).addReg(MBlaze::R0);
+
+    // lwi  R19, R1, stack_loc
+    BuildMI(MBB, MBBI, dl, TII.get(MBlaze::LWI), MBlaze::R19)
+      .addReg(MBlaze::R1).addImm(FPOffset);
+  }
+
+  // lwi R15, R1, stack_loc
+  if (MFI->adjustsStack() || requiresRA) {
+    BuildMI(MBB, MBBI, dl, TII.get(MBlaze::LWI), MBlaze::R15)
+      .addReg(MBlaze::R1).addImm(RAOffset);
+  }
+
+  // Get the number of bytes from FrameInfo
+  int StackSize = (int) MFI->getStackSize();
+
+  // addi R1, R1, imm
+  if (StackSize) {
+    BuildMI(MBB, MBBI, dl, TII.get(MBlaze::ADDIK), MBlaze::R1)
+      .addReg(MBlaze::R1).addImm(StackSize);
+  }
+}
+
+void MBlazeFrameLowering::
+processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+                                     RegScavenger *RS) const {
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
+  llvm::CallingConv::ID CallConv = MF.getFunction()->getCallingConv();
+  bool requiresRA = CallConv == llvm::CallingConv::MBLAZE_INTR;
+
+  if (MFI->adjustsStack() || requiresRA) {
+    MBlazeFI->setRAStackOffset(0);
+    MFI->CreateFixedObject(4,0,true);
+  }
+
+  if (hasFP(MF)) {
+    MBlazeFI->setFPStackOffset(4);
+    MFI->CreateFixedObject(4,4,true);
+  }
+
+  interruptFrameLayout(MF);
+  analyzeFrameIndexes(MF);
+}