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
diff --git a/lib/Target/ARM/Thumb1FrameLowering.cpp b/lib/Target/ARM/Thumb1FrameLowering.cpp
new file mode 100644
index 0000000..e3f2d2d
--- /dev/null
+++ b/lib/Target/ARM/Thumb1FrameLowering.cpp
@@ -0,0 +1,345 @@
+//======- Thumb1FrameLowering.cpp - Thumb1 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 Thumb1 implementation of TargetFrameLowering class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Thumb1FrameLowering.h"
+#include "ARMBaseInstrInfo.h"
+#include "ARMMachineFunctionInfo.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+
+using namespace llvm;
+
+bool Thumb1FrameLowering::hasReservedCallFrame(const MachineFunction &MF) const {
+ const MachineFrameInfo *FFI = MF.getFrameInfo();
+ unsigned CFSize = FFI->getMaxCallFrameSize();
+ // It's not always a good idea to include the call frame as part of the
+ // stack frame. ARM (especially Thumb) has small immediate offset to
+ // address the stack frame. So a large call frame can cause poor codegen
+ // and may even makes it impossible to scavenge a register.
+ if (CFSize >= ((1 << 8) - 1) * 4 / 2) // Half of imm8 * 4
+ return false;
+
+ return !MF.getFrameInfo()->hasVarSizedObjects();
+}
+
+static void emitSPUpdate(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &MBBI,
+ const TargetInstrInfo &TII, DebugLoc dl,
+ const Thumb1RegisterInfo &MRI,
+ int NumBytes) {
+ emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, ARM::SP, NumBytes, TII,
+ MRI, dl);
+}
+
+void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const {
+ MachineBasicBlock &MBB = MF.front();
+ MachineBasicBlock::iterator MBBI = MBB.begin();
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+ const Thumb1RegisterInfo *RegInfo =
+ static_cast<const Thumb1RegisterInfo*>(MF.getTarget().getRegisterInfo());
+ const Thumb1InstrInfo &TII =
+ *static_cast<const Thumb1InstrInfo*>(MF.getTarget().getInstrInfo());
+
+ unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
+ unsigned NumBytes = MFI->getStackSize();
+ const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
+ DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+ unsigned FramePtr = RegInfo->getFrameRegister(MF);
+ unsigned BasePtr = RegInfo->getBaseRegister();
+
+ // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4.
+ NumBytes = (NumBytes + 3) & ~3;
+ MFI->setStackSize(NumBytes);
+
+ // Determine the sizes of each callee-save spill areas and record which frame
+ // belongs to which callee-save spill areas.
+ unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
+ int FramePtrSpillFI = 0;
+
+ if (VARegSaveSize)
+ emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -VARegSaveSize);
+
+ if (!AFI->hasStackFrame()) {
+ if (NumBytes != 0)
+ emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes);
+ return;
+ }
+
+ for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
+ unsigned Reg = CSI[i].getReg();
+ int FI = CSI[i].getFrameIdx();
+ switch (Reg) {
+ case ARM::R4:
+ case ARM::R5:
+ case ARM::R6:
+ case ARM::R7:
+ case ARM::LR:
+ if (Reg == FramePtr)
+ FramePtrSpillFI = FI;
+ AFI->addGPRCalleeSavedArea1Frame(FI);
+ GPRCS1Size += 4;
+ break;
+ case ARM::R8:
+ case ARM::R9:
+ case ARM::R10:
+ case ARM::R11:
+ if (Reg == FramePtr)
+ FramePtrSpillFI = FI;
+ if (STI.isTargetDarwin()) {
+ AFI->addGPRCalleeSavedArea2Frame(FI);
+ GPRCS2Size += 4;
+ } else {
+ AFI->addGPRCalleeSavedArea1Frame(FI);
+ GPRCS1Size += 4;
+ }
+ break;
+ default:
+ AFI->addDPRCalleeSavedAreaFrame(FI);
+ DPRCSSize += 8;
+ }
+ }
+
+ if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) {
+ ++MBBI;
+ if (MBBI != MBB.end())
+ dl = MBBI->getDebugLoc();
+ }
+
+ // Determine starting offsets of spill areas.
+ unsigned DPRCSOffset = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
+ unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
+ unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
+ AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
+ AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
+ AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
+ AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
+ NumBytes = DPRCSOffset;
+
+ // Adjust FP so it point to the stack slot that contains the previous FP.
+ if (hasFP(MF)) {
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
+ .addFrameIndex(FramePtrSpillFI).addImm(0);
+ if (NumBytes > 7)
+ // If offset is > 7 then sp cannot be adjusted in a single instruction,
+ // try restoring from fp instead.
+ AFI->setShouldRestoreSPFromFP(true);
+ }
+
+ if (NumBytes)
+ // Insert it after all the callee-save spills.
+ emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, -NumBytes);
+
+ if (STI.isTargetELF() && hasFP(MF))
+ MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
+ AFI->getFramePtrSpillOffset());
+
+ AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
+ AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
+ AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
+
+ // If we need a base pointer, set it up here. It's whatever the value
+ // of the stack pointer is at this point. Any variable size objects
+ // will be allocated after this, so we can still use the base pointer
+ // to reference locals.
+ if (RegInfo->hasBasePointer(MF))
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), BasePtr).addReg(ARM::SP);
+}
+
+static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
+ for (unsigned i = 0; CSRegs[i]; ++i)
+ if (Reg == CSRegs[i])
+ return true;
+ return false;
+}
+
+static bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) {
+ if (MI->getOpcode() == ARM::tRestore &&
+ MI->getOperand(1).isFI() &&
+ isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs))
+ return true;
+ else if (MI->getOpcode() == ARM::tPOP) {
+ // The first two operands are predicates. The last two are
+ // imp-def and imp-use of SP. Check everything in between.
+ for (int i = 2, e = MI->getNumOperands() - 2; i != e; ++i)
+ if (!isCalleeSavedRegister(MI->getOperand(i).getReg(), CSRegs))
+ return false;
+ return true;
+ }
+ return false;
+}
+
+void Thumb1FrameLowering::emitEpilogue(MachineFunction &MF,
+ MachineBasicBlock &MBB) const {
+ MachineBasicBlock::iterator MBBI = prior(MBB.end());
+ assert((MBBI->getOpcode() == ARM::tBX_RET ||
+ MBBI->getOpcode() == ARM::tPOP_RET) &&
+ "Can only insert epilog into returning blocks");
+ DebugLoc dl = MBBI->getDebugLoc();
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+ const Thumb1RegisterInfo *RegInfo =
+ static_cast<const Thumb1RegisterInfo*>(MF.getTarget().getRegisterInfo());
+ const Thumb1InstrInfo &TII =
+ *static_cast<const Thumb1InstrInfo*>(MF.getTarget().getInstrInfo());
+
+ unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
+ int NumBytes = (int)MFI->getStackSize();
+ const unsigned *CSRegs = RegInfo->getCalleeSavedRegs();
+ unsigned FramePtr = RegInfo->getFrameRegister(MF);
+
+ if (!AFI->hasStackFrame()) {
+ if (NumBytes != 0)
+ emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, NumBytes);
+ } else {
+ // Unwind MBBI to point to first LDR / VLDRD.
+ if (MBBI != MBB.begin()) {
+ do
+ --MBBI;
+ while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs));
+ if (!isCSRestore(MBBI, CSRegs))
+ ++MBBI;
+ }
+
+ // Move SP to start of FP callee save spill area.
+ NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
+ AFI->getGPRCalleeSavedArea2Size() +
+ AFI->getDPRCalleeSavedAreaSize());
+
+ if (AFI->shouldRestoreSPFromFP()) {
+ NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
+ // Reset SP based on frame pointer only if the stack frame extends beyond
+ // frame pointer stack slot or target is ELF and the function has FP.
+ if (NumBytes) {
+ assert(MF.getRegInfo().isPhysRegUsed(ARM::R4) &&
+ "No scratch register to restore SP from FP!");
+ emitThumbRegPlusImmediate(MBB, MBBI, ARM::R4, FramePtr, -NumBytes,
+ TII, *RegInfo, dl);
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
+ .addReg(ARM::R4);
+ } else
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVtgpr2gpr), ARM::SP)
+ .addReg(FramePtr);
+ } else {
+ if (MBBI->getOpcode() == ARM::tBX_RET &&
+ &MBB.front() != MBBI &&
+ prior(MBBI)->getOpcode() == ARM::tPOP) {
+ MachineBasicBlock::iterator PMBBI = prior(MBBI);
+ emitSPUpdate(MBB, PMBBI, TII, dl, *RegInfo, NumBytes);
+ } else
+ emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, NumBytes);
+ }
+ }
+
+ if (VARegSaveSize) {
+ // Unlike T2 and ARM mode, the T1 pop instruction cannot restore
+ // to LR, and we can't pop the value directly to the PC since
+ // we need to update the SP after popping the value. Therefore, we
+ // pop the old LR into R3 as a temporary.
+
+ // Move back past the callee-saved register restoration
+ while (MBBI != MBB.end() && isCSRestore(MBBI, CSRegs))
+ ++MBBI;
+ // Epilogue for vararg functions: pop LR to R3 and branch off it.
+ AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
+ .addReg(ARM::R3, RegState::Define);
+
+ emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, VARegSaveSize);
+
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg))
+ .addReg(ARM::R3, RegState::Kill);
+ // erase the old tBX_RET instruction
+ MBB.erase(MBBI);
+ }
+}
+
+bool Thumb1FrameLowering::
+spillCalleeSavedRegisters(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ const std::vector<CalleeSavedInfo> &CSI,
+ const TargetRegisterInfo *TRI) const {
+ if (CSI.empty())
+ return false;
+
+ DebugLoc DL;
+ MachineFunction &MF = *MBB.getParent();
+ const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
+
+ if (MI != MBB.end()) DL = MI->getDebugLoc();
+
+ MachineInstrBuilder MIB = BuildMI(MBB, MI, DL, TII.get(ARM::tPUSH));
+ AddDefaultPred(MIB);
+ for (unsigned i = CSI.size(); i != 0; --i) {
+ unsigned Reg = CSI[i-1].getReg();
+ bool isKill = true;
+
+ // Add the callee-saved register as live-in unless it's LR and
+ // @llvm.returnaddress is called. If LR is returned for @llvm.returnaddress
+ // then it's already added to the function and entry block live-in sets.
+ if (Reg == ARM::LR) {
+ MachineFunction &MF = *MBB.getParent();
+ if (MF.getFrameInfo()->isReturnAddressTaken() &&
+ MF.getRegInfo().isLiveIn(Reg))
+ isKill = false;
+ }
+
+ if (isKill)
+ MBB.addLiveIn(Reg);
+
+ MIB.addReg(Reg, getKillRegState(isKill));
+ }
+ return true;
+}
+
+bool Thumb1FrameLowering::
+restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator MI,
+ const std::vector<CalleeSavedInfo> &CSI,
+ const TargetRegisterInfo *TRI) const {
+ if (CSI.empty())
+ return false;
+
+ MachineFunction &MF = *MBB.getParent();
+ ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
+ const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
+
+ bool isVarArg = AFI->getVarArgsRegSaveSize() > 0;
+ DebugLoc DL = MI->getDebugLoc();
+ MachineInstrBuilder MIB = BuildMI(MF, DL, TII.get(ARM::tPOP));
+ AddDefaultPred(MIB);
+
+ bool NumRegs = false;
+ for (unsigned i = CSI.size(); i != 0; --i) {
+ unsigned Reg = CSI[i-1].getReg();
+ if (Reg == ARM::LR) {
+ // Special epilogue for vararg functions. See emitEpilogue
+ if (isVarArg)
+ continue;
+ Reg = ARM::PC;
+ (*MIB).setDesc(TII.get(ARM::tPOP_RET));
+ MI = MBB.erase(MI);
+ }
+ MIB.addReg(Reg, getDefRegState(true));
+ NumRegs = true;
+ }
+
+ // It's illegal to emit pop instruction without operands.
+ if (NumRegs)
+ MBB.insert(MI, &*MIB);
+ else
+ MF.DeleteMachineInstr(MIB);
+
+ return true;
+}