-//=======- MipsFrameLowering.cpp - Mips Frame Information ------*- C++ -*-====//
+//===-- MipsFrameLowering.cpp - Mips Frame Information --------------------===//
//
// The LLVM Compiler Infrastructure
//
//===----------------------------------------------------------------------===//
#include "MipsFrameLowering.h"
+#include "MipsAnalyzeImmediate.h"
#include "MipsInstrInfo.h"
#include "MipsMachineFunction.h"
+#include "MipsTargetMachine.h"
+#include "MCTargetDesc/MipsBaseInfo.h"
#include "llvm/Function.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
//
//===----------------------------------------------------------------------===//
+const MipsFrameLowering *MipsFrameLowering::create(MipsTargetMachine &TM,
+ const MipsSubtarget &ST) {
+ if (TM.getSubtargetImpl()->inMips16Mode())
+ return llvm::createMips16FrameLowering(ST);
+
+ return llvm::createMipsSEFrameLowering(ST);
+}
+
// 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 MipsFrameLowering::hasFP(const MachineFunction &MF) const {
const MachineFrameInfo *MFI = MF.getFrameInfo();
- return DisableFramePointerElim(MF) || MFI->hasVarSizedObjects();
-}
-
-void MipsFrameLowering::adjustMipsStackFrame(MachineFunction &MF) const {
- MachineFrameInfo *MFI = MF.getFrameInfo();
- MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
- const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
- unsigned StackAlign = getStackAlignment();
- unsigned RegSize = STI.isGP32bit() ? 4 : 8;
- bool HasGP = MipsFI->needGPSaveRestore();
-
- // Min and Max CSI FrameIndex.
- int MinCSFI = -1, MaxCSFI = -1;
-
- // See the description at MipsMachineFunction.h
- int TopCPUSavedRegOff = -1, TopFPUSavedRegOff = -1;
-
- // Replace the dummy '0' SPOffset by the negative offsets, as explained on
- // LowerFormalArguments. Leaving '0' for while is necessary to avoid the
- // approach done by calculateFrameObjectOffsets to the stack frame.
- MipsFI->adjustLoadArgsFI(MFI);
- MipsFI->adjustStoreVarArgsFI(MFI);
-
- // It happens that the default stack frame allocation order does not directly
- // map to the convention used for mips. So we must fix it. We move the callee
- // save register slots after the local variables area, as described in the
- // stack frame above.
- unsigned CalleeSavedAreaSize = 0;
- if (!CSI.empty()) {
- MinCSFI = CSI[0].getFrameIdx();
- MaxCSFI = CSI[CSI.size()-1].getFrameIdx();
- }
- for (unsigned i = 0, e = CSI.size(); i != e; ++i)
- CalleeSavedAreaSize += MFI->getObjectAlignment(CSI[i].getFrameIdx());
-
- unsigned StackOffset = HasGP ? (MipsFI->getGPStackOffset()+RegSize)
- : (STI.isABI_O32() ? 16 : 0);
-
- // Adjust local variables. They should come on the stack right
- // after the arguments.
- int LastOffsetFI = -1;
- for (int i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
- if (i >= MinCSFI && i <= MaxCSFI)
- continue;
- if (MFI->isDeadObjectIndex(i))
- continue;
- unsigned Offset =
- StackOffset + MFI->getObjectOffset(i) - CalleeSavedAreaSize;
- if (LastOffsetFI == -1)
- LastOffsetFI = i;
- if (Offset > MFI->getObjectOffset(LastOffsetFI))
- LastOffsetFI = i;
- MFI->setObjectOffset(i, Offset);
- }
-
- // Adjust CPU Callee Saved Registers Area. Registers RA and FP must
- // be saved in this CPU Area. This whole area must be aligned to the
- // default Stack Alignment requirements.
- if (LastOffsetFI >= 0)
- StackOffset = MFI->getObjectOffset(LastOffsetFI)+
- MFI->getObjectSize(LastOffsetFI);
- StackOffset = ((StackOffset+StackAlign-1)/StackAlign*StackAlign);
-
- for (unsigned i = 0, e = CSI.size(); i != e ; ++i) {
- unsigned Reg = CSI[i].getReg();
- if (!Mips::CPURegsRegisterClass->contains(Reg))
- break;
- MFI->setObjectOffset(CSI[i].getFrameIdx(), StackOffset);
- TopCPUSavedRegOff = StackOffset;
- StackOffset += MFI->getObjectAlignment(CSI[i].getFrameIdx());
- }
-
- StackOffset = ((StackOffset+StackAlign-1)/StackAlign*StackAlign);
-
- // Adjust FPU Callee Saved Registers Area. This Area must be
- // aligned to the default Stack Alignment requirements.
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- unsigned Reg = CSI[i].getReg();
- if (Mips::CPURegsRegisterClass->contains(Reg))
- continue;
- MFI->setObjectOffset(CSI[i].getFrameIdx(), StackOffset);
- TopFPUSavedRegOff = StackOffset;
- StackOffset += MFI->getObjectAlignment(CSI[i].getFrameIdx());
- }
- StackOffset = ((StackOffset+StackAlign-1)/StackAlign*StackAlign);
-
- // Update frame info
- MFI->setStackSize(StackOffset);
-
- // Recalculate the final tops offset. The final values must be '0'
- // if there isn't a callee saved register for CPU or FPU, otherwise
- // a negative offset is needed.
- if (TopCPUSavedRegOff >= 0)
- MipsFI->setCPUTopSavedRegOff(TopCPUSavedRegOff-StackOffset);
-
- if (TopFPUSavedRegOff >= 0)
- MipsFI->setFPUTopSavedRegOff(TopFPUSavedRegOff-StackOffset);
-}
-
-
-// expand pair of register and immediate if the immediate doesn't fit in the
-// 16-bit offset field.
-// e.g.
-// if OrigImm = 0x10000, OrigReg = $sp:
-// generate the following sequence of instrs:
-// lui $at, hi(0x10000)
-// addu $at, $sp, $at
-//
-// (NewReg, NewImm) = ($at, lo(Ox10000))
-// return true
-static bool expandRegLargeImmPair(unsigned OrigReg, int OrigImm,
- unsigned& NewReg, int& NewImm,
- MachineBasicBlock& MBB,
- MachineBasicBlock::iterator I) {
- // OrigImm fits in the 16-bit field
- if (OrigImm < 0x8000 && OrigImm >= -0x8000) {
- NewReg = OrigReg;
- NewImm = OrigImm;
- return false;
- }
-
- MachineFunction* MF = MBB.getParent();
- const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
- DebugLoc DL = I->getDebugLoc();
- int ImmLo = OrigImm & 0xffff;
- int ImmHi = (((unsigned)OrigImm & 0xffff0000) >> 16) +
- ((OrigImm & 0x8000) != 0);
-
- // FIXME: change this when mips goes MC".
- BuildMI(MBB, I, DL, TII->get(Mips::NOAT));
- BuildMI(MBB, I, DL, TII->get(Mips::LUi), Mips::AT).addImm(ImmHi);
- BuildMI(MBB, I, DL, TII->get(Mips::ADDu), Mips::AT).addReg(OrigReg)
- .addReg(Mips::AT);
- NewReg = Mips::AT;
- NewImm = ImmLo;
-
- return true;
-}
-
-void MipsFrameLowering::emitPrologue(MachineFunction &MF) const {
- MachineBasicBlock &MBB = MF.front();
- MachineFrameInfo *MFI = MF.getFrameInfo();
- MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
- const MipsRegisterInfo *RegInfo =
- static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
- const MipsInstrInfo &TII =
- *static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
- MachineBasicBlock::iterator MBBI = MBB.begin();
- DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
- bool isPIC = (MF.getTarget().getRelocationModel() == Reloc::PIC_);
- unsigned NewReg = 0;
- int NewImm = 0;
- bool ATUsed;
-
- // Get the right frame order for Mips.
- adjustMipsStackFrame(MF);
-
- // Get the number of bytes to allocate from the FrameInfo.
- unsigned StackSize = MFI->getStackSize();
-
- BuildMI(MBB, MBBI, dl, TII.get(Mips::NOREORDER));
-
- // TODO: check need from GP here.
- if (isPIC && STI.isABI_O32())
- BuildMI(MBB, MBBI, dl, TII.get(Mips::CPLOAD))
- .addReg(RegInfo->getPICCallReg());
- BuildMI(MBB, MBBI, dl, TII.get(Mips::NOMACRO));
-
- // No need to allocate space on the stack.
- if (StackSize == 0 && !MFI->adjustsStack()) return;
-
- // Adjust stack : addi sp, sp, (-imm)
- ATUsed = expandRegLargeImmPair(Mips::SP, -StackSize, NewReg, NewImm, MBB,
- MBBI);
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
- .addReg(NewReg).addImm(NewImm);
-
- // FIXME: change this when mips goes MC".
- if (ATUsed)
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
-
- // if framepointer enabled, set it to point to the stack pointer.
- if (hasFP(MF)) {
- // Find the instruction past the last instruction that saves a callee-saved
- // register to the stack.
- const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
-
- for (unsigned i = 0; i < CSI.size(); ++i)
- ++MBBI;
-
- // Insert instruction "move $fp, $sp" at this location.
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDu), Mips::FP)
- .addReg(Mips::SP).addReg(Mips::ZERO);
- }
-
- // Restore GP from the saved stack location
- if (MipsFI->needGPSaveRestore())
- BuildMI(MBB, MBBI, dl, TII.get(Mips::CPRESTORE))
- .addImm(MipsFI->getGPStackOffset());
-}
-
-void MipsFrameLowering::emitEpilogue(MachineFunction &MF,
- MachineBasicBlock &MBB) const {
- MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
- MachineFrameInfo *MFI = MF.getFrameInfo();
- const MipsInstrInfo &TII =
- *static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
- DebugLoc dl = MBBI->getDebugLoc();
-
- // Get the number of bytes from FrameInfo
- unsigned StackSize = MFI->getStackSize();
-
- unsigned NewReg = 0;
- int NewImm = 0;
- bool ATUsed = false;
-
- // if framepointer enabled, restore the stack pointer.
- if (hasFP(MF)) {
- // Find the first instruction that restores a callee-saved register.
- MachineBasicBlock::iterator I = MBBI;
-
- for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
- --I;
-
- // Insert instruction "move $sp, $fp" at this location.
- BuildMI(MBB, I, dl, TII.get(Mips::ADDu), Mips::SP)
- .addReg(Mips::FP).addReg(Mips::ZERO);
- }
-
- // adjust stack : insert addi sp, sp, (imm)
- if (StackSize) {
- ATUsed = expandRegLargeImmPair(Mips::SP, StackSize, NewReg, NewImm, MBB,
- MBBI);
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ADDiu), Mips::SP)
- .addReg(NewReg).addImm(NewImm);
-
- // FIXME: change this when mips goes MC".
- if (ATUsed)
- BuildMI(MBB, MBBI, dl, TII.get(Mips::ATMACRO));
- }
-}
-
-void MipsFrameLowering::
-processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
- RegScavenger *RS) const {
- MachineRegisterInfo& MRI = MF.getRegInfo();
- MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
-
- // FIXME: remove this code if register allocator can correctly mark
- // $fp and $ra used or unused.
-
- // Mark $fp and $ra as used or unused.
- if (hasFP(MF))
- MRI.setPhysRegUsed(Mips::FP);
-
- // The register allocator might determine $ra is used after seeing
- // instruction "jr $ra", but we do not want PrologEpilogInserter to insert
- // instructions to save/restore $ra unless there is a function call.
- // To correct this, $ra is explicitly marked unused if there is no
- // function call.
- if (MipsFI->hasCall())
- MRI.setPhysRegUsed(Mips::RA);
- else
- MRI.setPhysRegUnused(Mips::RA);
-}
-
-void MipsFrameLowering::
-processFunctionBeforeFrameFinalized(MachineFunction &MF) const {
- const MipsRegisterInfo *RegInfo =
- static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());
- RegInfo->processFunctionBeforeFrameFinalized(MF);
+ return MF.getTarget().Options.DisableFramePointerElim(MF) ||
+ MFI->hasVarSizedObjects() || MFI->isFrameAddressTaken();
}