257 lines
9.7 KiB
C++
257 lines
9.7 KiB
C++
//===-- SPUTargetMachine.cpp - Define TargetMachine for Cell SPU ----------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Top-level implementation for the Cell SPU target.
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//
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//===----------------------------------------------------------------------===//
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#include "SPUFrameLowering.h"
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#include "SPU.h"
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#include "SPUInstrBuilder.h"
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#include "SPUInstrInfo.h"
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#include "llvm/Function.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/RegisterScavenging.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Support/CommandLine.h"
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using namespace llvm;
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//===----------------------------------------------------------------------===//
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// SPUFrameLowering:
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//===----------------------------------------------------------------------===//
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SPUFrameLowering::SPUFrameLowering(const SPUSubtarget &sti)
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: TargetFrameLowering(TargetFrameLowering::StackGrowsDown, 16, 0),
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Subtarget(sti) {
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LR[0].first = SPU::R0;
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LR[0].second = 16;
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}
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//--------------------------------------------------------------------------
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// hasFP - Return true if the specified function actually has a dedicated frame
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// pointer register. This is true if the function needs a frame pointer and has
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// a non-zero stack size.
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bool SPUFrameLowering::hasFP(const MachineFunction &MF) const {
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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return MFI->getStackSize() &&
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(MF.getTarget().Options.DisableFramePointerElim(MF) ||
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MFI->hasVarSizedObjects());
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}
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/// determineFrameLayout - Determine the size of the frame and maximum call
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/// frame size.
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void SPUFrameLowering::determineFrameLayout(MachineFunction &MF) const {
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MachineFrameInfo *MFI = MF.getFrameInfo();
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// Get the number of bytes to allocate from the FrameInfo
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unsigned FrameSize = MFI->getStackSize();
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// Get the alignments provided by the target, and the maximum alignment
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// (if any) of the fixed frame objects.
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unsigned TargetAlign = getStackAlignment();
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unsigned Align = std::max(TargetAlign, MFI->getMaxAlignment());
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assert(isPowerOf2_32(Align) && "Alignment is not power of 2");
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unsigned AlignMask = Align - 1;
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// Get the maximum call frame size of all the calls.
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unsigned maxCallFrameSize = MFI->getMaxCallFrameSize();
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// If we have dynamic alloca then maxCallFrameSize needs to be aligned so
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// that allocations will be aligned.
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if (MFI->hasVarSizedObjects())
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maxCallFrameSize = (maxCallFrameSize + AlignMask) & ~AlignMask;
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// Update maximum call frame size.
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MFI->setMaxCallFrameSize(maxCallFrameSize);
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// Include call frame size in total.
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FrameSize += maxCallFrameSize;
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// Make sure the frame is aligned.
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FrameSize = (FrameSize + AlignMask) & ~AlignMask;
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// Update frame info.
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MFI->setStackSize(FrameSize);
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}
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void SPUFrameLowering::emitPrologue(MachineFunction &MF) const {
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MachineBasicBlock &MBB = MF.front(); // Prolog goes in entry BB
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MachineBasicBlock::iterator MBBI = MBB.begin();
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const SPUInstrInfo &TII =
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*static_cast<const SPUInstrInfo*>(MF.getTarget().getInstrInfo());
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MachineModuleInfo &MMI = MF.getMMI();
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DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
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// Prepare for debug frame info.
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bool hasDebugInfo = MMI.hasDebugInfo();
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MCSymbol *FrameLabel = 0;
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// Move MBBI back to the beginning of the function.
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MBBI = MBB.begin();
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// Work out frame sizes.
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determineFrameLayout(MF);
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int FrameSize = MFI->getStackSize();
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assert((FrameSize & 0xf) == 0
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&& "SPURegisterInfo::emitPrologue: FrameSize not aligned");
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// the "empty" frame size is 16 - just the register scavenger spill slot
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if (FrameSize > 16 || MFI->adjustsStack()) {
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FrameSize = -(FrameSize + SPUFrameLowering::minStackSize());
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if (hasDebugInfo) {
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// Mark effective beginning of when frame pointer becomes valid.
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FrameLabel = MMI.getContext().CreateTempSymbol();
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BuildMI(MBB, MBBI, dl, TII.get(SPU::PROLOG_LABEL)).addSym(FrameLabel);
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}
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// Adjust stack pointer, spilling $lr -> 16($sp) and $sp -> -FrameSize($sp)
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// for the ABI
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BuildMI(MBB, MBBI, dl, TII.get(SPU::STQDr32), SPU::R0).addImm(16)
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.addReg(SPU::R1);
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if (isInt<10>(FrameSize)) {
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// Spill $sp to adjusted $sp
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BuildMI(MBB, MBBI, dl, TII.get(SPU::STQDr32), SPU::R1).addImm(FrameSize)
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.addReg(SPU::R1);
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// Adjust $sp by required amout
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BuildMI(MBB, MBBI, dl, TII.get(SPU::AIr32), SPU::R1).addReg(SPU::R1)
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.addImm(FrameSize);
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} else if (isInt<16>(FrameSize)) {
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// Frame size can be loaded into ILr32n, so temporarily spill $r2 and use
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// $r2 to adjust $sp:
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BuildMI(MBB, MBBI, dl, TII.get(SPU::STQDr128), SPU::R2)
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.addImm(-16)
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.addReg(SPU::R1);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::ILr32), SPU::R2)
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.addImm(FrameSize);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::STQXr32), SPU::R1)
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.addReg(SPU::R2)
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.addReg(SPU::R1);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::Ar32), SPU::R1)
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.addReg(SPU::R1)
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.addReg(SPU::R2);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::SFIr32), SPU::R2)
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.addReg(SPU::R2)
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.addImm(16);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::LQXr128), SPU::R2)
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.addReg(SPU::R2)
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.addReg(SPU::R1);
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} else {
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report_fatal_error("Unhandled frame size: " + Twine(FrameSize));
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}
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if (hasDebugInfo) {
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std::vector<MachineMove> &Moves = MMI.getFrameMoves();
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// Show update of SP.
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MachineLocation SPDst(MachineLocation::VirtualFP);
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MachineLocation SPSrc(MachineLocation::VirtualFP, -FrameSize);
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Moves.push_back(MachineMove(FrameLabel, SPDst, SPSrc));
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// Add callee saved registers to move list.
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const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
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for (unsigned I = 0, E = CSI.size(); I != E; ++I) {
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int Offset = MFI->getObjectOffset(CSI[I].getFrameIdx());
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unsigned Reg = CSI[I].getReg();
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if (Reg == SPU::R0) continue;
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MachineLocation CSDst(MachineLocation::VirtualFP, Offset);
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MachineLocation CSSrc(Reg);
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Moves.push_back(MachineMove(FrameLabel, CSDst, CSSrc));
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}
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// Mark effective beginning of when frame pointer is ready.
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MCSymbol *ReadyLabel = MMI.getContext().CreateTempSymbol();
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BuildMI(MBB, MBBI, dl, TII.get(SPU::PROLOG_LABEL)).addSym(ReadyLabel);
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MachineLocation FPDst(SPU::R1);
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MachineLocation FPSrc(MachineLocation::VirtualFP);
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Moves.push_back(MachineMove(ReadyLabel, FPDst, FPSrc));
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}
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}
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}
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void SPUFrameLowering::emitEpilogue(MachineFunction &MF,
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MachineBasicBlock &MBB) const {
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MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
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const SPUInstrInfo &TII =
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*static_cast<const SPUInstrInfo*>(MF.getTarget().getInstrInfo());
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const MachineFrameInfo *MFI = MF.getFrameInfo();
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int FrameSize = MFI->getStackSize();
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int LinkSlotOffset = SPUFrameLowering::stackSlotSize();
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DebugLoc dl = MBBI->getDebugLoc();
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assert(MBBI->getOpcode() == SPU::RET &&
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"Can only insert epilog into returning blocks");
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assert((FrameSize & 0xf) == 0 && "FrameSize not aligned");
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// the "empty" frame size is 16 - just the register scavenger spill slot
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if (FrameSize > 16 || MFI->adjustsStack()) {
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FrameSize = FrameSize + SPUFrameLowering::minStackSize();
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if (isInt<10>(FrameSize + LinkSlotOffset)) {
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// Reload $lr, adjust $sp by required amount
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// Note: We do this to slightly improve dual issue -- not by much, but it
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// is an opportunity for dual issue.
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BuildMI(MBB, MBBI, dl, TII.get(SPU::LQDr128), SPU::R0)
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.addImm(FrameSize + LinkSlotOffset)
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.addReg(SPU::R1);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::AIr32), SPU::R1)
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.addReg(SPU::R1)
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.addImm(FrameSize);
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} else if (FrameSize <= (1 << 16) - 1 && FrameSize >= -(1 << 16)) {
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// Frame size can be loaded into ILr32n, so temporarily spill $r2 and use
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// $r2 to adjust $sp:
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BuildMI(MBB, MBBI, dl, TII.get(SPU::STQDr128), SPU::R2)
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.addImm(16)
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.addReg(SPU::R1);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::ILr32), SPU::R2)
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.addImm(FrameSize);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::Ar32), SPU::R1)
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.addReg(SPU::R1)
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.addReg(SPU::R2);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::LQDr128), SPU::R0)
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.addImm(16)
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.addReg(SPU::R1);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::SFIr32), SPU::R2).
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addReg(SPU::R2)
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.addImm(16);
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BuildMI(MBB, MBBI, dl, TII.get(SPU::LQXr128), SPU::R2)
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.addReg(SPU::R2)
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.addReg(SPU::R1);
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} else {
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report_fatal_error("Unhandled frame size: " + Twine(FrameSize));
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}
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}
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}
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void SPUFrameLowering::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
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RegScavenger *RS) const{
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// Mark LR and SP unused, since the prolog spills them to stack and
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// we don't want anyone else to spill them for us.
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//
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// Also, unless R2 is really used someday, don't spill it automatically.
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MF.getRegInfo().setPhysRegUnused(SPU::R0);
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MF.getRegInfo().setPhysRegUnused(SPU::R1);
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MF.getRegInfo().setPhysRegUnused(SPU::R2);
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MachineFrameInfo *MFI = MF.getFrameInfo();
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const TargetRegisterClass *RC = &SPU::R32CRegClass;
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RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
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RC->getAlignment(),
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false));
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}
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