// stack frame indexes.
unsigned MinCSFrameIndex, MaxCSFrameIndex;
- // Entry and return blocks of the current function.
- MachineBasicBlock *EntryBlock;
- SmallVector<MachineBasicBlock *, 4> ReturnBlocks;
+ // Save and Restore blocks of the current function.
+ MachineBasicBlock *SaveBlock;
+ SmallVector<MachineBasicBlock *, 4> RestoreBlocks;
// Flag to control whether to use the register scavenger to resolve
// frame index materialization registers. Set according to
/// Compute the set of return blocks
void PEI::calculateSets(MachineFunction &Fn) {
- // Sets used to compute spill, restore placement sets.
- const std::vector<CalleeSavedInfo> &CSI =
- Fn.getFrameInfo()->getCalleeSavedInfo();
+ const MachineFrameInfo *MFI = Fn.getFrameInfo();
- // If no CSRs used, we are done.
- if (CSI.empty())
+ // Even when we do not change any CSR, we still want to insert the
+ // prologue and epilogue of the function.
+ // So set the save points for those.
+
+ // Use the points found by shrink-wrapping, if any.
+ if (MFI->getSavePoint()) {
+ SaveBlock = MFI->getSavePoint();
+ assert(MFI->getRestorePoint() && "Both restore and save must be set");
+ RestoreBlocks.push_back(MFI->getRestorePoint());
return;
+ }
// Save refs to entry and return blocks.
- EntryBlock = Fn.begin();
+ SaveBlock = Fn.begin();
for (MachineFunction::iterator MBB = Fn.begin(), E = Fn.end();
MBB != E; ++MBB)
if (isReturnBlock(MBB))
- ReturnBlocks.push_back(MBB);
+ RestoreBlocks.push_back(MBB);
return;
}
}
delete RS;
- ReturnBlocks.clear();
+ RestoreBlocks.clear();
return true;
}
bool AdjustsStack = MFI->adjustsStack();
// Get the function call frame set-up and tear-down instruction opcode
- int FrameSetupOpcode = TII.getCallFrameSetupOpcode();
- int FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
+ unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
+ unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
// Early exit for targets which have no call frame setup/destroy pseudo
// instructions.
- if (FrameSetupOpcode == -1 && FrameDestroyOpcode == -1)
+ if (FrameSetupOpcode == ~0u && FrameDestroyOpcode == ~0u)
return;
std::vector<MachineBasicBlock::iterator> FrameSDOps;
MFI->setCalleeSavedInfo(CSI);
}
+/// Helper function to update the liveness information for the callee-saved
+/// registers.
+static void updateLiveness(MachineFunction &MF) {
+ MachineFrameInfo *MFI = MF.getFrameInfo();
+ // Visited will contain all the basic blocks that are in the region
+ // where the callee saved registers are alive:
+ // - Anything that is not Save or Restore -> LiveThrough.
+ // - Save -> LiveIn.
+ // - Restore -> LiveOut.
+ // The live-out is not attached to the block, so no need to keep
+ // Restore in this set.
+ SmallPtrSet<MachineBasicBlock *, 8> Visited;
+ SmallVector<MachineBasicBlock *, 8> WorkList;
+ MachineBasicBlock *Entry = &MF.front();
+ MachineBasicBlock *Save = MFI->getSavePoint();
+
+ if (!Save)
+ Save = Entry;
+
+ if (Entry != Save) {
+ WorkList.push_back(Entry);
+ Visited.insert(Entry);
+ }
+ Visited.insert(Save);
+
+ MachineBasicBlock *Restore = MFI->getRestorePoint();
+ if (Restore)
+ // By construction Restore cannot be visited, otherwise it
+ // means there exists a path to Restore that does not go
+ // through Save.
+ WorkList.push_back(Restore);
+
+ while (!WorkList.empty()) {
+ const MachineBasicBlock *CurBB = WorkList.pop_back_val();
+ // By construction, the region that is after the save point is
+ // dominated by the Save and post-dominated by the Restore.
+ if (CurBB == Save)
+ continue;
+ // Enqueue all the successors not already visited.
+ // Those are by construction either before Save or after Restore.
+ for (MachineBasicBlock *SuccBB : CurBB->successors())
+ if (Visited.insert(SuccBB).second)
+ WorkList.push_back(SuccBB);
+ }
+
+ const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
+
+ for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
+ for (MachineBasicBlock *MBB : Visited)
+ // Add the callee-saved register as live-in.
+ // It's killed at the spill.
+ MBB->addLiveIn(CSI[i].getReg());
+ }
+}
+
/// insertCSRSpillsAndRestores - Insert spill and restore code for
/// callee saved registers used in the function.
///
MachineBasicBlock::iterator I;
// Spill using target interface.
- I = EntryBlock->begin();
- if (!TFI->spillCalleeSavedRegisters(*EntryBlock, I, CSI, TRI)) {
+ I = SaveBlock->begin();
+ if (!TFI->spillCalleeSavedRegisters(*SaveBlock, I, CSI, TRI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- // Add the callee-saved register as live-in.
- // It's killed at the spill.
- EntryBlock->addLiveIn(CSI[i].getReg());
-
// Insert the spill to the stack frame.
unsigned Reg = CSI[i].getReg();
const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
- TII.storeRegToStackSlot(*EntryBlock, I, Reg, true, CSI[i].getFrameIdx(),
+ TII.storeRegToStackSlot(*SaveBlock, I, Reg, true, CSI[i].getFrameIdx(),
RC, TRI);
}
}
+ // Update the live-in information of all the blocks up to the save point.
+ updateLiveness(Fn);
// Restore using target interface.
- for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri) {
- MachineBasicBlock *MBB = ReturnBlocks[ri];
+ for (MachineBasicBlock *MBB : RestoreBlocks) {
I = MBB->end();
- --I;
// Skip over all terminator instructions, which are part of the return
// sequence.
const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
// Add prologue to the function...
- TFI.emitPrologue(Fn);
+ TFI.emitPrologue(Fn, *SaveBlock);
- // Add epilogue to restore the callee-save registers in each exiting block
- for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
- // If last instruction is a return instruction, add an epilogue
- if (!I->empty() && I->back().isReturn())
- TFI.emitEpilogue(Fn, *I);
- }
+ // Add epilogue to restore the callee-save registers in each exiting block.
+ for (MachineBasicBlock *RestoreBlock : RestoreBlocks)
+ TFI.emitEpilogue(Fn, *RestoreBlock);
// Emit additional code that is required to support segmented stacks, if
// we've been asked for it. This, when linked with a runtime with support
// for segmented stacks (libgcc is one), will result in allocating stack
// space in small chunks instead of one large contiguous block.
if (Fn.shouldSplitStack())
- TFI.adjustForSegmentedStacks(Fn);
+ TFI.adjustForSegmentedStacks(Fn, *SaveBlock);
// Emit additional code that is required to explicitly handle the stack in
// HiPE native code (if needed) when loaded in the Erlang/OTP runtime. The
// different conditional check and another BIF for allocating more stack
// space.
if (Fn.getFunction()->getCallingConv() == CallingConv::HiPE)
- TFI.adjustForHiPEPrologue(Fn);
+ TFI.adjustForHiPEPrologue(Fn, *SaveBlock);
}
/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical
const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
const TargetRegisterInfo &TRI = *Fn.getSubtarget().getRegisterInfo();
const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
- int FrameSetupOpcode = TII.getCallFrameSetupOpcode();
- int FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
+ unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
+ unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
if (RS && !FrameIndexVirtualScavenging) RS->enterBasicBlock(BB);
projects / oota-llvm.git / blobdiff