void HexagonFrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineBasicBlock::iterator MBBI = MBB.begin();
const HexagonRegisterInfo *QRI =
MF.getSubtarget<HexagonSubtarget>().getRegisterInfo();
DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
determineFrameLayout(MF);
// Get the number of bytes to allocate from the FrameInfo.
int NumBytes = (int) MFI->getStackSize();
// LLVM expects allocframe not to be the first instruction in the
// basic block.
MachineBasicBlock::iterator InsertPt = MBB.begin();
//
// ALLOCA adjust regs. Iterate over ADJDYNALLOC nodes and change the offset.
//
HexagonMachineFunctionInfo *FuncInfo =
MF.getInfo<HexagonMachineFunctionInfo>();
const std::vector<MachineInstr*>& AdjustRegs =
FuncInfo->getAllocaAdjustInsts();
for (std::vector<MachineInstr*>::const_iterator i = AdjustRegs.begin(),
e = AdjustRegs.end();
i != e; ++i) {
MachineInstr* MI = *i;
assert((MI->getOpcode() == Hexagon::ADJDYNALLOC) &&
"Expected adjust alloca node");
MachineOperand& MO = MI->getOperand(2);
assert(MO.isImm() && "Expected immediate");
MO.setImm(MFI->getMaxCallFrameSize());
}
//
// Only insert ALLOCFRAME if we need to.
//
if (hasFP(MF)) {
// Check for overflow.
// Hexagon_TODO: Ugh! hardcoding. Is there an API that can be used?
const int ALLOCFRAME_MAX = 16384;
const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
if (NumBytes >= ALLOCFRAME_MAX) {
// Emit allocframe(#0).
BuildMI(MBB, InsertPt, dl, TII.get(Hexagon::S2_allocframe)).addImm(0);
// Subtract offset from frame pointer.
BuildMI(MBB, InsertPt, dl, TII.get(Hexagon::CONST32_Int_Real),
HEXAGON_RESERVED_REG_1).addImm(NumBytes);
BuildMI(MBB, InsertPt, dl, TII.get(Hexagon::A2_sub),
QRI->getStackRegister()).
addReg(QRI->getStackRegister()).
addReg(HEXAGON_RESERVED_REG_1);
} else {
BuildMI(MBB, InsertPt, dl, TII.get(Hexagon::S2_allocframe)).addImm(NumBytes);
}
}
}
void HexagonFrameLowering::emitPrologue(MachineFunction &MF) const {
MachineBasicBlock &MBB = MF.front();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineModuleInfo &MMI = MF.getMMI();
MachineBasicBlock::iterator MBBI = MBB.begin();
const HexagonRegisterInfo *QRI =
static_cast<const HexagonRegisterInfo *>(MF.getTarget().getRegisterInfo());
DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
determineFrameLayout(MF);
// Check if frame moves are needed for EH.
bool needsFrameMoves = MMI.hasDebugInfo() ||
!MF.getFunction()->needsUnwindTableEntry();
// Get the number of bytes to allocate from the FrameInfo.
int NumBytes = (int) MFI->getStackSize();
// LLVM expects allocframe not to be the first instruction in the
// basic block.
MachineBasicBlock::iterator InsertPt = MBB.begin();
//
// ALLOCA adjust regs. Iterate over ADJDYNALLOC nodes and change the offset.
//
HexagonMachineFunctionInfo *FuncInfo =
MF.getInfo<HexagonMachineFunctionInfo>();
const std::vector<MachineInstr*>& AdjustRegs =
FuncInfo->getAllocaAdjustInsts();
for (std::vector<MachineInstr*>::const_iterator i = AdjustRegs.begin(),
e = AdjustRegs.end();
i != e; ++i) {
MachineInstr* MI = *i;
assert((MI->getOpcode() == Hexagon::ADJDYNALLOC) &&
"Expected adjust alloca node");
MachineOperand& MO = MI->getOperand(2);
assert(MO.isImm() && "Expected immediate");
MO.setImm(MFI->getMaxCallFrameSize());
}
std::vector<MachineMove> &Moves = MMI.getFrameMoves();
if (needsFrameMoves) {
// Advance CFA. DW_CFA_def_cfa
unsigned FPReg = QRI->getFrameRegister();
unsigned RAReg = QRI->getRARegister();
MachineLocation Dst(MachineLocation::VirtualFP);
MachineLocation Src(FPReg, -8);
Moves.push_back(MachineMove(0, Dst, Src));
// R31 = (R31 - #4)
MachineLocation LRDst(RAReg, -4);
MachineLocation LRSrc(RAReg);
Moves.push_back(MachineMove(0, LRDst, LRSrc));
// R30 = (R30 - #8)
MachineLocation SPDst(FPReg, -8);
MachineLocation SPSrc(FPReg);
Moves.push_back(MachineMove(0, SPDst, SPSrc));
}
//
// Only insert ALLOCFRAME if we need to.
//
if (hasFP(MF)) {
// Check for overflow.
// Hexagon_TODO: Ugh! hardcoding. Is there an API that can be used?
const int ALLOCFRAME_MAX = 16384;
const TargetInstrInfo &TII = *MF.getTarget().getInstrInfo();
if (NumBytes >= ALLOCFRAME_MAX) {
// Emit allocframe(#0).
BuildMI(MBB, InsertPt, dl, TII.get(Hexagon::ALLOCFRAME)).addImm(0);
// Subtract offset from frame pointer.
BuildMI(MBB, InsertPt, dl, TII.get(Hexagon::CONST32_Int_Real),
HEXAGON_RESERVED_REG_1).addImm(NumBytes);
BuildMI(MBB, InsertPt, dl, TII.get(Hexagon::SUB_rr),
QRI->getStackRegister()).
addReg(QRI->getStackRegister()).
addReg(HEXAGON_RESERVED_REG_1);
} else {
BuildMI(MBB, InsertPt, dl, TII.get(Hexagon::ALLOCFRAME)).addImm(NumBytes);
}
}
}
