//
//===----------------------------------------------------------------------===//
-#include "PrologEpilogInserter.h"
#include "llvm/ADT/IndexedMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/CodeGen/StackProtector.h"
+#include "llvm/CodeGen/WinEHFuncInfo.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/LLVMContext.h"
#define DEBUG_TYPE "pei"
+namespace {
+class PEI : public MachineFunctionPass {
+public:
+ static char ID;
+ PEI() : MachineFunctionPass(ID) {
+ initializePEIPass(*PassRegistry::getPassRegistry());
+ }
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+ /// runOnMachineFunction - Insert prolog/epilog code and replace abstract
+ /// frame indexes with appropriate references.
+ ///
+ bool runOnMachineFunction(MachineFunction &Fn) override;
+
+private:
+ RegScavenger *RS;
+
+ // MinCSFrameIndex, MaxCSFrameIndex - Keeps the range of callee saved
+ // stack frame indexes.
+ unsigned MinCSFrameIndex, MaxCSFrameIndex;
+
+ // Save and Restore blocks of the current function. Typically there is a
+ // single save block, unless Windows EH funclets are involved.
+ SmallVector<MachineBasicBlock *, 1> SaveBlocks;
+ SmallVector<MachineBasicBlock *, 4> RestoreBlocks;
+
+ // Flag to control whether to use the register scavenger to resolve
+ // frame index materialization registers. Set according to
+ // TRI->requiresFrameIndexScavenging() for the current function.
+ bool FrameIndexVirtualScavenging;
+
+ void calculateSets(MachineFunction &Fn);
+ void calculateCallsInformation(MachineFunction &Fn);
+ void assignCalleeSavedSpillSlots(MachineFunction &Fn,
+ const BitVector &SavedRegs);
+ void insertCSRSpillsAndRestores(MachineFunction &Fn);
+ void calculateFrameObjectOffsets(MachineFunction &Fn);
+ void replaceFrameIndices(MachineFunction &Fn);
+ void replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
+ int &SPAdj);
+ void scavengeFrameVirtualRegs(MachineFunction &Fn);
+ void insertPrologEpilogCode(MachineFunction &Fn);
+
+ // Convenience for recognizing return blocks.
+ bool isReturnBlock(const MachineBasicBlock *MBB) const;
+};
+} // namespace
+
char PEI::ID = 0;
char &llvm::PrologEpilogCodeInserterID = PEI::ID;
MachineFunctionPass::getAnalysisUsage(AU);
}
-bool PEI::isReturnBlock(MachineBasicBlock* MBB) {
+bool PEI::isReturnBlock(const MachineBasicBlock* MBB) const {
return (MBB && !MBB->empty() && MBB->back().isReturn());
}
/// 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();
-
- // If no CSRs used, we are done.
- if (CSI.empty())
+ const MachineFrameInfo *MFI = Fn.getFrameInfo();
+
+ // 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()) {
+ SaveBlocks.push_back(MFI->getSavePoint());
+ assert(MFI->getRestorePoint() && "Both restore and save must be set");
+ MachineBasicBlock *RestoreBlock = MFI->getRestorePoint();
+ // If RestoreBlock does not have any successor and is not a return block
+ // then the end point is unreachable and we do not need to insert any
+ // epilogue.
+ if (!RestoreBlock->succ_empty() || isReturnBlock(RestoreBlock))
+ RestoreBlocks.push_back(RestoreBlock);
return;
+ }
// Save refs to entry and return blocks.
- EntryBlock = Fn.begin();
- for (MachineFunction::iterator MBB = Fn.begin(), E = Fn.end();
- MBB != E; ++MBB)
- if (isReturnBlock(MBB))
- ReturnBlocks.push_back(MBB);
-
- return;
+ SaveBlocks.push_back(Fn.begin());
+ for (MachineBasicBlock &MBB : Fn) {
+ if (MBB.isEHFuncletEntry())
+ SaveBlocks.push_back(&MBB);
+ if (isReturnBlock(&MBB))
+ RestoreBlocks.push_back(&MBB);
+ }
}
/// StackObjSet - A set of stack object indexes
// instructions.
calculateCallsInformation(Fn);
- // Allow the target machine to make some adjustments to the function
- // e.g. UsedPhysRegs before calculateCalleeSavedRegisters.
- TFI->processFunctionBeforeCalleeSavedScan(Fn, RS);
+ // Determine which of the registers in the callee save list should be saved.
+ BitVector SavedRegs;
+ TFI->determineCalleeSaves(Fn, SavedRegs, RS);
- // Scan the function for modified callee saved registers and insert spill code
- // for any callee saved registers that are modified.
- calculateCalleeSavedRegisters(Fn);
+ // Insert spill code for any callee saved registers that are modified.
+ assignCalleeSavedSpillSlots(Fn, SavedRegs);
// Determine placement of CSR spill/restore code:
// place all spills in the entry block, all restores in return blocks.
}
delete RS;
- ReturnBlocks.clear();
+ SaveBlocks.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;
}
}
-
-/// calculateCalleeSavedRegisters - Scan the function for modified callee saved
-/// registers.
-void PEI::calculateCalleeSavedRegisters(MachineFunction &F) {
- const TargetRegisterInfo *RegInfo = F.getSubtarget().getRegisterInfo();
- const TargetFrameLowering *TFI = F.getSubtarget().getFrameLowering();
- MachineFrameInfo *MFI = F.getFrameInfo();
-
- // Get the callee saved register list...
- const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&F);
-
+void PEI::assignCalleeSavedSpillSlots(MachineFunction &F,
+ const BitVector &SavedRegs) {
// These are used to keep track the callee-save area. Initialize them.
MinCSFrameIndex = INT_MAX;
MaxCSFrameIndex = 0;
- // Early exit for targets which have no callee saved registers.
- if (!CSRegs || CSRegs[0] == 0)
+ if (SavedRegs.empty())
return;
- // In Naked functions we aren't going to save any registers.
- if (F.getFunction()->hasFnAttribute(Attribute::Naked))
- return;
+ const TargetRegisterInfo *RegInfo = F.getSubtarget().getRegisterInfo();
+ const MCPhysReg *CSRegs = RegInfo->getCalleeSavedRegs(&F);
std::vector<CalleeSavedInfo> CSI;
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
- // Functions which call __builtin_unwind_init get all their registers saved.
- if (F.getRegInfo().isPhysRegUsed(Reg) || F.getMMI().callsUnwindInit()) {
- // If the reg is modified, save it!
+ if (SavedRegs.test(Reg))
CSI.push_back(CalleeSavedInfo(Reg));
- }
}
+ const TargetFrameLowering *TFI = F.getSubtarget().getFrameLowering();
+ MachineFrameInfo *MFI = F.getFrameInfo();
if (!TFI->assignCalleeSavedSpillSlots(F, RegInfo, CSI)) {
// If target doesn't implement this, use generic code.
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)) {
- 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(),
- RC, TRI);
+ 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);
+ }
}
+ // 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.
unsigned Align = MFI->getObjectAlignment(i);
// Adjust to alignment boundary
- Offset = (Offset+Align-1)/Align*Align;
+ Offset = RoundUpToAlignment(Offset, Align);
MFI->setObjectOffset(i, -Offset); // Set the computed offset
}
for (int i = MaxCSFI; i >= MinCSFI ; --i) {
unsigned Align = MFI->getObjectAlignment(i);
// Adjust to alignment boundary
- Offset = (Offset+Align-1)/Align*Align;
+ Offset = RoundUpToAlignment(Offset, Align);
MFI->setObjectOffset(i, Offset);
Offset += MFI->getObjectSize(i);
unsigned Align = MFI->getLocalFrameMaxAlign();
// Adjust to alignment boundary.
- Offset = (Offset + Align - 1) / Align * Align;
+ Offset = RoundUpToAlignment(Offset, Align);
DEBUG(dbgs() << "Local frame base offset: " << Offset << "\n");
// If the frame pointer is eliminated, all frame offsets will be relative to
// SP not FP. Align to MaxAlign so this works.
StackAlign = std::max(StackAlign, MaxAlign);
- unsigned AlignMask = StackAlign - 1;
- Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
+ Offset = RoundUpToAlignment(Offset, StackAlign);
}
// Update frame info to pretend that this is part of the stack...
const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
// Add prologue to the function...
- TFI.emitPrologue(Fn);
+ for (MachineBasicBlock *SaveBlock : SaveBlocks)
+ 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);
+ if (Fn.shouldSplitStack()) {
+ for (MachineBasicBlock *SaveBlock : SaveBlocks)
+ 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);
+ for (MachineBasicBlock *SaveBlock : SaveBlocks)
+ TFI.adjustForHiPEPrologue(Fn, *SaveBlock);
}
/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical
/// register references and actual offsets.
///
void PEI::replaceFrameIndices(MachineFunction &Fn) {
- if (!Fn.getFrameInfo()->hasStackObjects()) return; // Nothing to do?
+ const TargetFrameLowering &TFI = *Fn.getSubtarget().getFrameLowering();
+ if (!TFI.needsFrameIndexResolution(Fn)) return;
+
+ MachineModuleInfo &MMI = Fn.getMMI();
+ const Function *F = Fn.getFunction();
+ const Function *ParentF = MMI.getWinEHParent(F);
+ unsigned FrameReg;
+ if (F == ParentF) {
+ WinEHFuncInfo &FuncInfo = MMI.getWinEHFuncInfo(Fn.getFunction());
+ // FIXME: This should be unconditional but we have bugs in the preparation
+ // pass.
+ if (FuncInfo.UnwindHelpFrameIdx != INT_MAX)
+ FuncInfo.UnwindHelpFrameOffset = TFI.getFrameIndexReferenceFromSP(
+ Fn, FuncInfo.UnwindHelpFrameIdx, FrameReg);
+ for (WinEHTryBlockMapEntry &TBME : FuncInfo.TryBlockMap) {
+ for (WinEHHandlerType &H : TBME.HandlerArray) {
+ unsigned UnusedReg;
+ if (H.CatchObj.FrameIndex == INT_MAX)
+ H.CatchObj.FrameOffset = INT_MAX;
+ else
+ H.CatchObj.FrameOffset =
+ TFI.getFrameIndexReference(Fn, H.CatchObj.FrameIndex, UnusedReg);
+ }
+ }
+ } else if (MMI.hasWinEHFuncInfo(F)) {
+ WinEHFuncInfo &FuncInfo = MMI.getWinEHFuncInfo(Fn.getFunction());
+ auto I = FuncInfo.CatchHandlerParentFrameObjIdx.find(F);
+ if (I != FuncInfo.CatchHandlerParentFrameObjIdx.end())
+ FuncInfo.CatchHandlerParentFrameObjOffset[F] =
+ TFI.getFrameIndexReferenceFromSP(Fn, I->second, FrameReg);
+ }
// Store SPAdj at exit of a basic block.
SmallVector<int, 8> SPState;
SmallPtrSet<MachineBasicBlock*, 8> Reachable;
// Iterate over the reachable blocks in DFS order.
- for (df_ext_iterator<MachineFunction*, SmallPtrSet<MachineBasicBlock*, 8> >
- DFI = df_ext_begin(&Fn, Reachable), DFE = df_ext_end(&Fn, Reachable);
+ for (auto DFI = df_ext_begin(&Fn, Reachable), DFE = df_ext_end(&Fn, Reachable);
DFI != DFE; ++DFI) {
int SPAdj = 0;
// Check the exit state of the DFS stack predecessor.
void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &Fn,
int &SPAdj) {
- const TargetMachine &TM = Fn.getTarget();
- assert(TM.getSubtargetImpl()->getRegisterInfo() &&
- "TM::getRegisterInfo() must be implemented!");
+ assert(Fn.getSubtarget().getRegisterInfo() &&
+ "getRegisterInfo() must be implemented!");
const TargetInstrInfo &TII = *Fn.getSubtarget().getInstrInfo();
- const TargetRegisterInfo &TRI = *TM.getSubtargetImpl()->getRegisterInfo();
- const TargetFrameLowering *TFI = TM.getSubtargetImpl()->getFrameLowering();
- bool StackGrowsDown =
- TFI->getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
- int FrameSetupOpcode = TII.getCallFrameSetupOpcode();
- int FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
+ const TargetRegisterInfo &TRI = *Fn.getSubtarget().getRegisterInfo();
+ const TargetFrameLowering *TFI = Fn.getSubtarget().getFrameLowering();
+ unsigned FrameSetupOpcode = TII.getCallFrameSetupOpcode();
+ unsigned FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
if (RS && !FrameIndexVirtualScavenging) RS->enterBasicBlock(BB);
+ bool InsideCallSequence = false;
+
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
- // Remember how much SP has been adjusted to create the call
- // frame.
- int Size = I->getOperand(0).getImm();
-
- if ((!StackGrowsDown && I->getOpcode() == FrameSetupOpcode) ||
- (StackGrowsDown && I->getOpcode() == FrameDestroyOpcode))
- Size = -Size;
-
- SPAdj += Size;
+ InsideCallSequence = (I->getOpcode() == FrameSetupOpcode);
+ SPAdj += TII.getSPAdjust(I);
MachineBasicBlock::iterator PrevI = BB->end();
if (I != BB->begin()) PrevI = std::prev(I);
if (!MI->getOperand(i).isFI())
continue;
- // Frame indicies in debug values are encoded in a target independent
+ // Frame indices in debug values are encoded in a target independent
// way with simply the frame index and offset rather than any
// target-specific addressing mode.
if (MI->isDebugValue()) {
- assert(i == 0 && "Frame indicies can only appear as the first "
+ assert(i == 0 && "Frame indices can only appear as the first "
"operand of a DBG_VALUE machine instruction");
unsigned Reg;
MachineOperand &Offset = MI->getOperand(1);
continue;
}
+ // TODO: This code should be commoned with the code for
+ // PATCHPOINT. There's no good reason for the difference in
+ // implementation other than historical accident. The only
+ // remaining difference is the unconditional use of the stack
+ // pointer as the base register.
+ if (MI->getOpcode() == TargetOpcode::STATEPOINT) {
+ assert((!MI->isDebugValue() || i == 0) &&
+ "Frame indicies can only appear as the first operand of a "
+ "DBG_VALUE machine instruction");
+ unsigned Reg;
+ MachineOperand &Offset = MI->getOperand(i + 1);
+ const unsigned refOffset =
+ TFI->getFrameIndexReferenceFromSP(Fn, MI->getOperand(i).getIndex(),
+ Reg);
+
+ Offset.setImm(Offset.getImm() + refOffset);
+ MI->getOperand(i).ChangeToRegister(Reg, false /*isDef*/);
+ continue;
+ }
+
// Some instructions (e.g. inline asm instructions) can have
// multiple frame indices and/or cause eliminateFrameIndex
// to insert more than one instruction. We need the register
break;
}
+ // If we are looking at a call sequence, we need to keep track of
+ // the SP adjustment made by each instruction in the sequence.
+ // This includes both the frame setup/destroy pseudos (handled above),
+ // as well as other instructions that have side effects w.r.t the SP.
+ // Note that this must come after eliminateFrameIndex, because
+ // if I itself referred to a frame index, we shouldn't count its own
+ // adjustment.
+ if (MI && InsideCallSequence)
+ SPAdj += TII.getSPAdjust(MI);
+
if (DoIncr && I != BB->end()) ++I;
// Update register states.
// Replace this reference to the virtual register with the
// scratch register.
assert (ScratchReg && "Missing scratch register!");
- MachineRegisterInfo &MRI = Fn.getRegInfo();
Fn.getRegInfo().replaceRegWith(Reg, ScratchReg);
- // Make sure MRI now accounts this register as used.
- MRI.setPhysRegUsed(ScratchReg);
-
// Because this instruction was processed by the RS before this
// register was allocated, make sure that the RS now records the
// register as being used.
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