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[PEI] Separate saving and restoring CSRs into different functions. NFC

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Split insertCSRSpillsAndRestores into insertCSRSaves + insertCSRRestores.

This is mostly useful for future shrink-wrapping improvements where we
want to save / restore a specific part of the CSRs in a specific block.

Differential Revision: https://reviews.llvm.org/D35644

llvm-svn: 308573
This commit is contained in:
Francis Visoiu Mistrih 2017-07-20 00:58:37 +00:00
parent 316eb09c53
commit 867b822cb5
1 changed files with 48 additions and 63 deletions
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111
lib/CodeGen/PrologEpilogInserter.cpp
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@ -455,76 +455,47 @@ static void updateLiveness(MachineFunction &MF) {
}
}
/// insertCSRSpillsAndRestores - Insert spill and restore code for
/// callee saved registers used in the function.
///
static void insertCSRSpillsAndRestores(MachineFunction &Fn,
const MBBVector &SaveBlocks,
const MBBVector &RestoreBlocks) {
// Get callee saved register information.
MachineFrameInfo &MFI = Fn.getFrameInfo();
const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();
MFI.setCalleeSavedInfoValid(true);
// Early exit if no callee saved registers are modified!
if (CSI.empty())
return;
/// Insert restore code for the callee-saved registers used in the function.
static void insertCSRSaves(MachineBasicBlock &SaveBlock,
ArrayRef<CalleeSavedInfo> CSI) {
MachineFunction &Fn = *SaveBlock.getParent();
const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
MachineBasicBlock::iterator I;
// Spill using target interface.
for (MachineBasicBlock *SaveBlock : SaveBlocks) {
I = SaveBlock->begin();
if (!TFI->spillCalleeSavedRegisters(*SaveBlock, I, CSI, TRI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
// Insert the spill to the stack frame.
unsigned Reg = CSI[i].getReg();
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
TII.storeRegToStackSlot(*SaveBlock, I, Reg, true, CSI[i].getFrameIdx(),
RC, TRI);
}
MachineBasicBlock::iterator I = SaveBlock.begin();
if (!TFI->spillCalleeSavedRegisters(SaveBlock, I, CSI, TRI)) {
for (const CalleeSavedInfo &CS : CSI) {
// Insert the spill to the stack frame.
unsigned Reg = CS.getReg();
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
TII.storeRegToStackSlot(SaveBlock, I, Reg, true, CS.getFrameIdx(), RC,
TRI);
}
// Update the live-in information of all the blocks up to the save point.
updateLiveness(Fn);
}
}
// Restore using target interface.
for (MachineBasicBlock *MBB : RestoreBlocks) {
I = MBB->end();
/// Insert restore code for the callee-saved registers used in the function.
static void insertCSRRestores(MachineBasicBlock &RestoreBlock,
ArrayRef<CalleeSavedInfo> CSI) {
MachineFunction &Fn = *RestoreBlock.getParent();
const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
// Skip over all terminator instructions, which are part of the return
// sequence.
MachineBasicBlock::iterator I2 = I;
while (I2 != MBB->begin() && (--I2)->isTerminator())
I = I2;
// Restore all registers immediately before the return and any
// terminators that precede it.
MachineBasicBlock::iterator I = RestoreBlock.getFirstTerminator();
bool AtStart = I == MBB->begin();
MachineBasicBlock::iterator BeforeI = I;
if (!AtStart)
--BeforeI;
// Restore all registers immediately before the return and any
// terminators that precede it.
if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
unsigned Reg = CSI[i].getReg();
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
TII.loadRegFromStackSlot(*MBB, I, Reg, CSI[i].getFrameIdx(), RC, TRI);
assert(I != MBB->begin() &&
"loadRegFromStackSlot didn't insert any code!");
// Insert in reverse order. loadRegFromStackSlot can insert
// multiple instructions.
if (AtStart)
I = MBB->begin();
else {
I = BeforeI;
++I;
}
}
if (!TFI->restoreCalleeSavedRegisters(RestoreBlock, I, CSI, TRI)) {
for (const CalleeSavedInfo &CI : reverse(CSI)) {
unsigned Reg = CI.getReg();
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
TII.loadRegFromStackSlot(RestoreBlock, I, Reg, CI.getFrameIdx(), RC, TRI);
assert(I != RestoreBlock.begin() &&
"loadRegFromStackSlot didn't insert any code!");
// Insert in reverse order. loadRegFromStackSlot can insert
// multiple instructions.
}
}
}
@ -532,6 +503,7 @@ static void insertCSRSpillsAndRestores(MachineFunction &Fn,
void PEI::doSpillCalleeSavedRegs(MachineFunction &Fn) {
const Function *F = Fn.getFunction();
const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
MachineFrameInfo &MFI = Fn.getFrameInfo();
MinCSFrameIndex = std::numeric_limits<unsigned>::max();
MaxCSFrameIndex = 0;
@ -543,8 +515,21 @@ void PEI::doSpillCalleeSavedRegs(MachineFunction &Fn) {
assignCalleeSavedSpillSlots(Fn, SavedRegs, MinCSFrameIndex, MaxCSFrameIndex);
// Add the code to save and restore the callee saved registers.
if (!F->hasFnAttribute(Attribute::Naked))
insertCSRSpillsAndRestores(Fn, SaveBlocks, RestoreBlocks);
if (!F->hasFnAttribute(Attribute::Naked)) {
MFI.setCalleeSavedInfoValid(true);
ArrayRef<CalleeSavedInfo> CSI = MFI.getCalleeSavedInfo();
if (!CSI.empty()) {
for (MachineBasicBlock *SaveBlock : SaveBlocks) {
insertCSRSaves(*SaveBlock, CSI);
// Update the live-in information of all the blocks up to the save
// point.
updateLiveness(Fn);
}
for (MachineBasicBlock *RestoreBlock : RestoreBlocks)
insertCSRRestores(*RestoreBlock, CSI);
}
}
}
/// AdjustStackOffset - Helper function used to adjust the stack frame offset.