PrologEpilogInserter.cpp [plain text]
#define DEBUG_TYPE "shrink-wrap"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetFrameInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/ADT/SparseBitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/STLExtras.h"
#include <climits>
#include <sstream>
using namespace llvm;
static cl::opt<bool>
ShrinkWrapping("shrink-wrap",
cl::desc("Apply shrink wrapping to callee-saved register spills/restores"));
namespace {
struct VISIBILITY_HIDDEN PEI : public MachineFunctionPass {
static char ID;
PEI() : MachineFunctionPass(&ID) {}
const char *getPassName() const {
return "Prolog/Epilog Insertion & Frame Finalization";
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
if (ShrinkWrapping) {
AU.addRequired<MachineLoopInfo>();
AU.addRequired<MachineDominatorTree>();
}
AU.addPreserved<MachineLoopInfo>();
AU.addPreserved<MachineDominatorTree>();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool runOnMachineFunction(MachineFunction &Fn) {
const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
RS = TRI->requiresRegisterScavenging(Fn) ? new RegScavenger() : NULL;
if (MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>())
Fn.getFrameInfo()->setMachineModuleInfo(MMI);
TRI->processFunctionBeforeCalleeSavedScan(Fn, RS);
calculateCalleeSavedRegisters(Fn);
placeCSRSpillsAndRestores(Fn);
insertCSRSpillsAndRestores(Fn);
TRI->processFunctionBeforeFrameFinalized(Fn);
calculateFrameObjectOffsets(Fn);
insertPrologEpilogCode(Fn);
replaceFrameIndices(Fn);
delete RS;
return true;
}
private:
RegScavenger *RS;
unsigned MinCSFrameIndex, MaxCSFrameIndex;
typedef SparseBitVector<> CSRegSet;
typedef DenseMap<MachineBasicBlock*, CSRegSet> CSRegBlockMap;
CSRegSet UsedCSRegs;
CSRegBlockMap CSRUsed;
CSRegBlockMap AnticIn, AnticOut;
CSRegBlockMap AvailIn, AvailOut;
CSRegBlockMap CSRSave;
CSRegBlockMap CSRRestore;
MachineBasicBlock* EntryBlock;
SmallVector<MachineBasicBlock*, 4> ReturnBlocks;
bool ShrinkWrapThisFunction;
bool calculateSets(MachineFunction &Fn);
void calculateAnticAvail(MachineFunction &Fn);
MachineBasicBlock* moveSpillsOutOfLoops(MachineFunction &Fn,
MachineBasicBlock* MBB);
void addRestoresForSBranchBlock(MachineFunction &Fn,
MachineBasicBlock* MBB);
void moveRestoresOutOfLoops(MachineFunction& Fn,
MachineBasicBlock* MBB,
std::vector<MachineBasicBlock*>& SBLKS);
void addSavesForRJoinBlocks(MachineFunction& Fn,
std::vector<MachineBasicBlock*>& SBLKS);
void placeSpillsAndRestores(MachineFunction &Fn);
void placeCSRSpillsAndRestores(MachineFunction &Fn);
void calculateCalleeSavedRegisters(MachineFunction &Fn);
void insertCSRSpillsAndRestores(MachineFunction &Fn);
void calculateFrameObjectOffsets(MachineFunction &Fn);
void replaceFrameIndices(MachineFunction &Fn);
void insertPrologEpilogCode(MachineFunction &Fn);
void initShrinkWrappingInfo() {
UsedCSRegs.clear();
CSRUsed.clear();
AnticIn.clear();
AnticOut.clear();
AvailIn.clear();
AvailOut.clear();
CSRSave.clear();
CSRRestore.clear();
EntryBlock = 0;
if (! ReturnBlocks.empty())
ReturnBlocks.clear();
ShrinkWrapThisFunction = ShrinkWrapping;
}
MachineBasicBlock* getTopLevelLoopPreheader(MachineLoop* LP) {
assert(LP && "Machine loop is NULL.");
MachineBasicBlock* PHDR = LP->getLoopPreheader();
MachineLoop* PLP = LP->getParentLoop();
while (PLP) {
PHDR = PLP->getLoopPreheader();
PLP = PLP->getParentLoop();
}
return PHDR;
}
MachineLoop* getTopLevelLoopParent(MachineLoop *LP) {
if (LP == 0)
return 0;
MachineLoop* PLP = LP->getParentLoop();
while (PLP) {
LP = PLP;
PLP = PLP->getParentLoop();
}
return LP;
}
#ifndef NDEBUG
static std::string getBasicBlockName(const MachineBasicBlock* MBB) {
std::ostringstream name;
if (MBB) {
if (MBB->getBasicBlock())
name << MBB->getBasicBlock()->getName();
else
name << "_MBB_" << MBB->getNumber();
}
return name.str();
}
static std::string stringifyCSRegSet(const CSRegSet& s,
MachineFunction &Fn) {
const TargetRegisterInfo* TRI = Fn.getTarget().getRegisterInfo();
const std::vector<CalleeSavedInfo> CSI =
Fn.getFrameInfo()->getCalleeSavedInfo();
std::ostringstream srep;
if (CSI.size() == 0) {
srep << "[]";
return srep.str();
}
srep << "[";
CSRegSet::iterator I = s.begin(), E = s.end();
if (I != E) {
unsigned reg = CSI[*I].getReg();
srep << TRI->getName(reg);
for (++I; I != E; ++I) {
reg = CSI[*I].getReg();
srep << ",";
srep << TRI->getName(reg);
}
}
srep << "]";
return srep.str();
}
static void dumpSet(const CSRegSet& s, MachineFunction &Fn) {
DOUT << stringifyCSRegSet(s, Fn) << "\n";
}
#endif
};
char PEI::ID = 0;
}
FunctionPass *llvm::createPrologEpilogCodeInserter() { return new PEI(); }
void PEI::placeCSRSpillsAndRestores(MachineFunction &Fn) {
#ifndef NDEBUG
DOUT << "Place CSR spills/restores for "
<< Fn.getFunction()->getName() << "\n";
#endif
initShrinkWrappingInfo();
if (calculateSets(Fn))
placeSpillsAndRestores(Fn);
}
void PEI::calculateAnticAvail(MachineFunction &Fn) {
bool changed = true;
unsigned iterations = 0;
while (changed) {
changed = false;
for (MachineFunction::iterator MBBI = Fn.begin(), MBBE = Fn.end();
MBBI != MBBE; ++MBBI) {
MachineBasicBlock* MBB = MBBI;
MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end();
if (SI != SE) {
CSRegSet prevAnticOut = AnticOut[MBB];
MachineBasicBlock* SUCC = *SI;
AnticOut[MBB] = AnticIn[SUCC];
for (++SI; SI != SE; ++SI) {
SUCC = *SI;
AnticOut[MBB] &= AnticIn[SUCC];
}
if (prevAnticOut != AnticOut[MBB])
changed = true;
}
CSRegSet prevAnticIn = AnticIn[MBB];
AnticIn[MBB] = CSRUsed[MBB] | AnticOut[MBB];
if (prevAnticIn |= AnticIn[MBB])
changed = true;
MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end();
if (PI != PE) {
CSRegSet prevAvailIn = AvailIn[MBB];
MachineBasicBlock* PRED = *PI;
AvailIn[MBB] = AvailOut[PRED];
for (++PI; PI != PE; ++PI) {
PRED = *PI;
AvailIn[MBB] &= AvailOut[PRED];
}
if (prevAvailIn != AvailIn[MBB])
changed = true;
}
CSRegSet prevAvailOut = AvailOut[MBB];
AvailOut[MBB] = CSRUsed[MBB] | AvailIn[MBB];
if (prevAvailOut |= AvailOut[MBB])
changed = true;
}
++iterations;
}
AnticIn[EntryBlock].clear();
AnticOut[EntryBlock].clear();
#ifndef NDEBUG
DOUT << "-----------------------------------------------------------\n";
DOUT << "iterations = " << iterations << "\n";
DOUT << "-----------------------------------------------------------\n";
DOUT << "MBB | ANTIC_IN | ANTIC_OUT | AVAIL_IN | AVAIL_OUT\n";
DOUT << "-----------------------------------------------------------\n";
for (MachineFunction::iterator MBBI = Fn.begin(), MBBE = Fn.end();
MBBI != MBBE; ++MBBI) {
MachineBasicBlock* MBB = MBBI;
DOUT << getBasicBlockName(MBB) << " | "
<< stringifyCSRegSet(AnticIn[MBB], Fn)
<< " | "
<< stringifyCSRegSet(AnticOut[MBB], Fn)
<< " | "
<< stringifyCSRegSet(AvailIn[MBB], Fn)
<< " | "
<< stringifyCSRegSet(AvailOut[MBB], Fn)
<< "\n";
}
#endif
}
bool PEI::calculateSets(MachineFunction &Fn) {
const std::vector<CalleeSavedInfo> CSI =
Fn.getFrameInfo()->getCalleeSavedInfo();
if (CSI.empty()) {
#ifndef NDEBUG
DOUT << Fn.getFunction()->getName()
<< " uses no callee-saved registers.\n";
#endif
return false;
}
#ifndef NDEBUG
DOUT << "-----------------------------------------------------------\n";
#endif
const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
bool allCSRUsesInEntryBlock = true;
EntryBlock = Fn.begin();
for (MachineFunction::iterator MBB = Fn.begin(), E = Fn.end();
MBB != E; ++MBB)
if (!MBB->empty() && MBB->back().getDesc().isReturn())
ReturnBlocks.push_back(MBB);
if (! ShrinkWrapThisFunction) {
for (unsigned inx = 0, e = CSI.size(); inx != e; ++inx) {
UsedCSRegs.set(inx);
CSRSave[EntryBlock].set(inx);
for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri)
CSRRestore[ReturnBlocks[ri]].set(inx);
}
return false;
}
for (MachineFunction::iterator MBBI = Fn.begin(), MBBE = Fn.end();
MBBI != MBBE; ++MBBI) {
MachineBasicBlock* MBB = MBBI;
for (MachineBasicBlock::iterator I = MBB->begin(); I != MBB->end(); ++I) {
for (unsigned inx = 0, e = CSI.size(); inx != e; ++inx) {
unsigned Reg = CSI[inx].getReg();
for (unsigned opInx = 0, opEnd = I->getNumOperands();
opInx != opEnd; ++opInx) {
const MachineOperand &MO = I->getOperand(opInx);
if (! (MO.isReg() && (MO.isUse() || MO.isDef())))
continue;
unsigned MOReg = MO.getReg();
if (!MOReg)
continue;
if (MOReg == Reg ||
(TargetRegisterInfo::isPhysicalRegister(MOReg) &&
TargetRegisterInfo::isPhysicalRegister(Reg) &&
TRI->isSubRegister(MOReg, Reg))) {
UsedCSRegs.set(inx);
CSRUsed[MBB].set(inx);
if (ShrinkWrapThisFunction) {
if (MBB == EntryBlock) {
CSRSave[MBB].set(inx);
for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri)
CSRRestore[ReturnBlocks[ri]].set(inx);
} else
allCSRUsesInEntryBlock = false;
} else {
CSRSave[EntryBlock].set(inx);
for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri)
CSRRestore[ReturnBlocks[ri]].set(inx);
}
}
}
}
}
#ifndef NDEBUG
DOUT << "CSRUsed[" << getBasicBlockName(MBB) << "] = "
<< stringifyCSRegSet(CSRUsed[MBB], Fn) << "\n";
#endif
}
#ifndef NDEBUG
DOUT << "UsedCSRegs = " << stringifyCSRegSet(UsedCSRegs, Fn) << "\n";
#endif
ShrinkWrapThisFunction = (ShrinkWrapping &&
ShrinkWrapThisFunction &&
! allCSRUsesInEntryBlock);
if (! ShrinkWrapThisFunction) {
return false;
}
calculateAnticAvail(Fn);
return true;
}
MachineBasicBlock* PEI::moveSpillsOutOfLoops(MachineFunction &Fn,
MachineBasicBlock* MBB) {
if (MBB == 0 || CSRSave[MBB].empty())
return 0;
MachineBasicBlock* DEST = 0;
MachineLoopInfo &LI = getAnalysis<MachineLoopInfo>();
if (MachineLoop* LP = LI.getLoopFor(MBB)) {
MachineBasicBlock* LPH = getTopLevelLoopPreheader(LP);
assert(LPH && "Loop has no top level preheader?");
#ifndef NDEBUG
DOUT << "Moving saves of "
<< stringifyCSRegSet(CSRSave[MBB], Fn)
<< " from " << getBasicBlockName(MBB)
<< " to " << getBasicBlockName(LPH) << "\n";
#endif
CSRSave[LPH] |= CSRSave[MBB];
if (LPH == EntryBlock) {
for (unsigned i = 0, e = ReturnBlocks.size(); i != e; ++i)
CSRRestore[ReturnBlocks[i]] |= CSRSave[MBB];
} else {
if (LPH->succ_size() > 1)
DEST = LPH;
}
CSRSave[MBB].clear();
} else if (MBB->succ_size() > 1)
DEST = MBB;
return DEST;
}
void PEI::addRestoresForSBranchBlock(MachineFunction &Fn,
MachineBasicBlock* MBB) {
if (MBB == 0 || CSRSave[MBB].empty() || MBB->succ_size() < 2)
return;
bool hasCSRUses = false;
for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end(); SI != SE; ++SI) {
MachineBasicBlock* SUCC = *SI;
bool needsRestore = false;
if (CSRUsed[SUCC].intersects(CSRSave[MBB])) {
hasCSRUses = true;
continue;
}
needsRestore = true;
for (df_iterator<MachineBasicBlock*> BI = df_begin(SUCC),
BE = df_end(SUCC); BI != BE; ++BI) {
MachineBasicBlock* SBB = *BI;
if (CSRUsed[SBB].intersects(CSRSave[MBB])) {
hasCSRUses = true;
needsRestore = false;
break;
}
}
if (needsRestore && hasCSRUses) {
#ifndef NDEBUG
DOUT << "MBB " << getBasicBlockName(MBB)
<< " needs a restore on path to successor "
<< getBasicBlockName(SUCC) << "\n";
#endif
CSRRestore[SUCC] = CSRSave[MBB];
}
}
}
void PEI::moveRestoresOutOfLoops(MachineFunction& Fn,
MachineBasicBlock* MBB,
std::vector<MachineBasicBlock*>& SBLKS) {
SBLKS.clear();
if (MBB == 0 || CSRRestore[MBB].empty())
return;
MachineLoopInfo &LI = getAnalysis<MachineLoopInfo>();
if (MachineLoop* LP = LI.getLoopFor(MBB)) {
LP = getTopLevelLoopParent(LP);
assert(LP && "Loop with no top level parent?");
SmallVector<MachineBasicBlock*, 4> exitBlocks;
LP->getExitBlocks(exitBlocks);
assert(exitBlocks.size() > 0 &&
"Loop has no top level exit blocks?");
for (unsigned i = 0, e = exitBlocks.size(); i != e; ++i) {
MachineBasicBlock* EXB = exitBlocks[i];
#ifndef NDEBUG
DOUT << "Moving restores of "
<< stringifyCSRegSet(CSRRestore[MBB], Fn)
<< " from " << getBasicBlockName(MBB)
<< " to " << getBasicBlockName(EXB) << "\n";
#endif
CSRRestore[EXB] |= CSRRestore[MBB];
if (EXB->pred_size() > 1)
SBLKS.push_back(EXB);
}
CSRRestore[MBB].clear();
} else if (MBB->pred_size() > 1)
SBLKS.push_back(MBB);
}
void PEI::addSavesForRJoinBlocks(MachineFunction& Fn,
std::vector<MachineBasicBlock*>& SBLKS) {
if (SBLKS.empty())
return;
for (unsigned i = 0, e = SBLKS.size(); i != e; ++i) {
MachineBasicBlock* MBB = SBLKS[i];
if (MBB->pred_size() > 1) {
bool needsSave = false;
for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end(); PI != PE; ++PI) {
MachineBasicBlock* PRED = *PI;
if (CSRUsed[PRED].intersects(CSRRestore[MBB]))
continue;
needsSave = true;
for (idf_iterator<MachineBasicBlock*> PPI = idf_begin(PRED),
PPE = idf_end(PRED); PPI != PPE; ++PPI) {
MachineBasicBlock* PBB = *PPI;
if (CSRUsed[PBB].intersects(CSRRestore[MBB])) {
needsSave = false;
break;
}
}
if (needsSave) {
#ifndef NDEBUG
DOUT << "MBB " << getBasicBlockName(MBB)
<< " needs a save on path from predecessor "
<< getBasicBlockName(PRED) << "\n";
#endif
CSRSave[PRED] = CSRRestore[MBB];
}
}
}
}
}
void PEI::placeSpillsAndRestores(MachineFunction &Fn) {
#ifndef NDEBUG
DOUT << "-----------------------------------------------------------\n";
#endif
for (MachineFunction::iterator MBBI = Fn.begin(), MBBE = Fn.end();
MBBI != MBBE; ++MBBI) {
MachineBasicBlock* MBB = MBBI;
if (MBB != EntryBlock) {
CSRegSet anticInPreds;
MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
PE = MBB->pred_end();
if (PI != PE) {
MachineBasicBlock* PRED = *PI;
anticInPreds = UsedCSRegs - AnticIn[PRED];
for (++PI; PI != PE; ++PI) {
PRED = *PI;
if (PRED != MBB)
anticInPreds &= (UsedCSRegs - AnticIn[PRED]);
}
}
CSRSave[MBB] = (AnticIn[MBB] - AvailIn[MBB]) & anticInPreds;
if (! CSRSave[MBB].empty() && ! CSRSave[EntryBlock].empty())
CSRSave[MBB] = CSRSave[MBB] - CSRSave[EntryBlock];
if (MachineBasicBlock* DESTBB = moveSpillsOutOfLoops(Fn, MBB)) {
addRestoresForSBranchBlock(Fn, DESTBB);
}
}
#ifndef NDEBUG
if (! CSRSave[MBB].empty())
DOUT << "SAVE[" << getBasicBlockName(MBB) << "] = "
<< stringifyCSRegSet(CSRSave[MBB], Fn) << "\n";
#endif
if (! CSRRestore[MBB].empty() || MBB->pred_size() == 0)
continue;
CSRegSet availOutSucc;
MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end();
if (SI != SE) {
MachineBasicBlock* SUCC = *SI;
availOutSucc = UsedCSRegs - AvailOut[SUCC];
for (++SI; SI != SE; ++SI) {
SUCC = *SI;
if (SUCC != MBB)
availOutSucc &= (UsedCSRegs - AvailOut[SUCC]);
}
} else if (! CSRUsed[MBB].empty()) {
availOutSucc = UsedCSRegs;
}
CSRRestore[MBB] = (AvailOut[MBB] - AnticOut[MBB]) & availOutSucc;
if (! CSRRestore[MBB].empty() && ! CSRSave[EntryBlock].empty())
CSRRestore[MBB] = CSRRestore[MBB] - CSRSave[EntryBlock];
std::vector<MachineBasicBlock*> saveBlocks;
moveRestoresOutOfLoops(Fn, MBB, saveBlocks);
addSavesForRJoinBlocks(Fn, saveBlocks);
#ifndef NDEBUG
if (! CSRRestore[MBB].empty())
DOUT << "RESTORE[" << getBasicBlockName(MBB) << "] = "
<< stringifyCSRegSet(CSRRestore[MBB], Fn) << "\n";
#endif
}
#ifndef NDEBUG
DOUT << "-----------------------------------------------------------\n";
DOUT << "Final SAVE, RESTORE:\n";
DOUT << "-----------------------------------------------------------\n";
for (MachineFunction::iterator MBB = Fn.begin(), E = Fn.end();
MBB != E; ++MBB) {
if (! CSRSave[MBB].empty()) {
DOUT << "SAVE[" << getBasicBlockName(MBB) << "] = "
<< stringifyCSRegSet(CSRSave[MBB], Fn);
if (CSRRestore[MBB].empty())
DOUT << "\n";
}
if (! CSRRestore[MBB].empty()) {
if (! CSRSave[MBB].empty())
DOUT << " ";
DOUT << "RESTORE[" << getBasicBlockName(MBB) << "] = "
<< stringifyCSRegSet(CSRRestore[MBB], Fn) << "\n";
}
}
#endif
}
void PEI::calculateCalleeSavedRegisters(MachineFunction &Fn) {
const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo();
const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(&Fn);
int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode();
int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode();
MinCSFrameIndex = INT_MAX;
MaxCSFrameIndex = 0;
if ((CSRegs == 0 || CSRegs[0] == 0) &&
FrameSetupOpcode == -1 && FrameDestroyOpcode == -1)
return;
unsigned MaxCallFrameSize = 0;
bool HasCalls = false;
std::vector<MachineBasicBlock::iterator> FrameSDOps;
for (MachineFunction::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB)
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ++I)
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
assert(I->getNumOperands() >= 1 && "Call Frame Setup/Destroy Pseudo"
" instructions should have a single immediate argument!");
unsigned Size = I->getOperand(0).getImm();
if (Size > MaxCallFrameSize) MaxCallFrameSize = Size;
HasCalls = true;
FrameSDOps.push_back(I);
}
MachineFrameInfo *FFI = Fn.getFrameInfo();
FFI->setHasCalls(HasCalls);
FFI->setMaxCallFrameSize(MaxCallFrameSize);
for (unsigned i = 0, e = FrameSDOps.size(); i != e; ++i) {
MachineBasicBlock::iterator I = FrameSDOps[i];
if (RegInfo->hasReservedCallFrame(Fn) || RegInfo->hasFP(Fn))
RegInfo->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
}
const TargetRegisterClass* const *CSRegClasses =
RegInfo->getCalleeSavedRegClasses(&Fn);
std::vector<CalleeSavedInfo> CSI;
for (unsigned i = 0; CSRegs[i]; ++i) {
unsigned Reg = CSRegs[i];
if (Fn.getRegInfo().isPhysRegUsed(Reg)) {
CSI.push_back(CalleeSavedInfo(Reg, CSRegClasses[i]));
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
*AliasSet; ++AliasSet) { if (Fn.getRegInfo().isPhysRegUsed(*AliasSet)) {
CSI.push_back(CalleeSavedInfo(Reg, CSRegClasses[i]));
break;
}
}
}
}
if (CSI.empty())
return;
unsigned NumFixedSpillSlots;
const std::pair<unsigned,int> *FixedSpillSlots =
TFI->getCalleeSavedSpillSlots(NumFixedSpillSlots);
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
unsigned Reg = CSI[i].getReg();
const TargetRegisterClass *RC = CSI[i].getRegClass();
const std::pair<unsigned,int> *FixedSlot = FixedSpillSlots;
while (FixedSlot != FixedSpillSlots+NumFixedSpillSlots &&
FixedSlot->first != Reg)
++FixedSlot;
int FrameIdx;
if (FixedSlot == FixedSpillSlots+NumFixedSpillSlots) {
unsigned Align = RC->getAlignment();
unsigned StackAlign = TFI->getStackAlignment();
Align = std::min(Align, StackAlign);
FrameIdx = FFI->CreateStackObject(RC->getSize(), Align);
if ((unsigned)FrameIdx < MinCSFrameIndex) MinCSFrameIndex = FrameIdx;
if ((unsigned)FrameIdx > MaxCSFrameIndex) MaxCSFrameIndex = FrameIdx;
} else {
FrameIdx = FFI->CreateFixedObject(RC->getSize(), FixedSlot->second);
}
CSI[i].setFrameIdx(FrameIdx);
}
FFI->setCalleeSavedInfo(CSI);
}
void PEI::insertCSRSpillsAndRestores(MachineFunction &Fn) {
MachineFrameInfo *FFI = Fn.getFrameInfo();
const std::vector<CalleeSavedInfo> &CSI = FFI->getCalleeSavedInfo();
if (CSI.empty())
return;
const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
MachineBasicBlock::iterator I;
std::vector<CalleeSavedInfo> blockCSI;
#ifndef NDEBUG
DOUT << "Inserting spill/restore code for CSRs in function "
<< Fn.getFunction()->getName() << "\n";
#endif
for (CSRegBlockMap::iterator
BI = CSRSave.begin(), BE = CSRSave.end(); BI != BE; ++BI) {
MachineBasicBlock* MBB = BI->first;
CSRegSet save = BI->second;
if (save.empty())
continue;
if (! ShrinkWrapThisFunction) {
I = MBB->begin();
if (!TII.spillCalleeSavedRegisters(*MBB, I, CSI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
MBB->addLiveIn(CSI[i].getReg());
TII.storeRegToStackSlot(*MBB, I, CSI[i].getReg(), true,
CSI[i].getFrameIdx(), CSI[i].getRegClass());
}
}
} else {
#ifndef NDEBUG
DOUT << "CSRSave[" << getBasicBlockName(MBB) << "] = "
<< stringifyCSRegSet(save, Fn) << "\n";
#endif
blockCSI.clear();
for (CSRegSet::iterator RI = save.begin(),
RE = save.end(); RI != RE; ++RI) {
blockCSI.push_back(CSI[*RI]);
}
assert(blockCSI.size() > 0 &&
"Could not collect callee saved register info");
if (! MBB->empty() && ! CSRUsed[MBB].intersects(save)) {
I = MBB->end();
--I;
if (I->getDesc().isCall()) {
++I;
} else {
MachineBasicBlock::iterator I2 = I;
while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator())
I = I2;
}
} else {
I = MBB->begin();
}
for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
MBB->addLiveIn(blockCSI[i].getReg());
TII.storeRegToStackSlot(*MBB, I, blockCSI[i].getReg(),
true,
blockCSI[i].getFrameIdx(),
blockCSI[i].getRegClass());
}
}
}
for (CSRegBlockMap::iterator
BI = CSRRestore.begin(), BE = CSRRestore.end(); BI != BE; ++BI) {
MachineBasicBlock* MBB = BI->first;
CSRegSet restore = BI->second;
if (restore.empty())
continue;
if (! ShrinkWrapThisFunction) {
I = MBB->end(); --I;
MachineBasicBlock::iterator I2 = I;
while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator())
I = I2;
bool AtStart = I == MBB->begin();
MachineBasicBlock::iterator BeforeI = I;
if (!AtStart)
--BeforeI;
if (!TII.restoreCalleeSavedRegisters(*MBB, I, CSI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
TII.loadRegFromStackSlot(*MBB, I, CSI[i].getReg(),
CSI[i].getFrameIdx(),
CSI[i].getRegClass());
assert(I != MBB->begin() &&
"loadRegFromStackSlot didn't insert any code!");
if (AtStart)
I = MBB->begin();
else {
I = BeforeI;
++I;
}
}
}
} else {
#ifndef NDEBUG
DOUT << "CSRRestore[" << getBasicBlockName(MBB) << "] = "
<< stringifyCSRegSet(restore, Fn) << "\n";
#endif
blockCSI.clear();
for (CSRegSet::iterator RI = restore.begin(),
RE = restore.end(); RI != RE; ++RI) {
blockCSI.push_back(CSI[*RI]);
}
assert(blockCSI.size() > 0 &&
"Could not find callee saved register info");
if (MBB->empty() || ! CSRUsed[MBB].intersects(restore)) {
I = MBB->begin();
} else {
I = MBB->end();
--I;
if (I->getDesc().isCall()) {
++I;
} else {
MachineBasicBlock::iterator I2 = I;
while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator())
I = I2;
}
}
bool AtStart = I == MBB->begin();
MachineBasicBlock::iterator BeforeI = I;
if (!AtStart)
--BeforeI;
#ifndef NDEBUG
if (! MBB->empty() && ! CSRUsed[MBB].intersects(restore)) {
MachineInstr* MI = BeforeI;
DOUT << "adding restore after ";
DEBUG(MI->dump());
} else {
DOUT << "adding restore to beginning of "
<< getBasicBlockName(MBB) << "\n";
}
#endif
for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
TII.loadRegFromStackSlot(*MBB, I, blockCSI[i].getReg(),
blockCSI[i].getFrameIdx(),
blockCSI[i].getRegClass());
assert(I != MBB->begin() &&
"loadRegFromStackSlot didn't insert any code!");
if (AtStart)
I = MBB->begin();
else {
I = BeforeI;
++I;
}
}
}
}
}
static inline void
AdjustStackOffset(MachineFrameInfo *FFI, int FrameIdx,
bool StackGrowsDown, int64_t &Offset,
unsigned &MaxAlign) {
if (StackGrowsDown)
Offset += FFI->getObjectSize(FrameIdx);
unsigned Align = FFI->getObjectAlignment(FrameIdx);
MaxAlign = std::max(MaxAlign, Align);
Offset = (Offset + Align - 1) / Align * Align;
if (StackGrowsDown) {
FFI->setObjectOffset(FrameIdx, -Offset); } else {
FFI->setObjectOffset(FrameIdx, Offset);
Offset += FFI->getObjectSize(FrameIdx);
}
}
void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo();
bool StackGrowsDown =
TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
MachineFrameInfo *FFI = Fn.getFrameInfo();
unsigned MaxAlign = FFI->getMaxAlignment();
int64_t Offset = TFI.getOffsetOfLocalArea();
if (StackGrowsDown)
Offset = -Offset;
assert(Offset >= 0
&& "Local area offset should be in direction of stack growth");
for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
int64_t FixedOff;
if (StackGrowsDown) {
FixedOff = -FFI->getObjectOffset(i);
} else {
FixedOff = FFI->getObjectOffset(i) + FFI->getObjectSize(i);
}
if (FixedOff > Offset) Offset = FixedOff;
}
if (StackGrowsDown) {
for (unsigned i = MinCSFrameIndex; i <= MaxCSFrameIndex; ++i) {
Offset += FFI->getObjectSize(i);
unsigned Align = FFI->getObjectAlignment(i);
MaxAlign = std::max(MaxAlign, Align);
Offset = (Offset+Align-1)/Align*Align;
FFI->setObjectOffset(i, -Offset); }
} else {
int MaxCSFI = MaxCSFrameIndex, MinCSFI = MinCSFrameIndex;
for (int i = MaxCSFI; i >= MinCSFI ; --i) {
unsigned Align = FFI->getObjectAlignment(i);
MaxAlign = std::max(MaxAlign, Align);
Offset = (Offset+Align-1)/Align*Align;
FFI->setObjectOffset(i, Offset);
Offset += FFI->getObjectSize(i);
}
}
const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
if (RS && RegInfo->hasFP(Fn)) {
int SFI = RS->getScavengingFrameIndex();
if (SFI >= 0)
AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
}
if (FFI->getStackProtectorIndex() >= 0)
AdjustStackOffset(FFI, FFI->getStackProtectorIndex(), StackGrowsDown,
Offset, MaxAlign);
for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
continue;
if (RS && (int)i == RS->getScavengingFrameIndex())
continue;
if (FFI->isDeadObjectIndex(i))
continue;
if (FFI->getStackProtectorIndex() == (int)i)
continue;
AdjustStackOffset(FFI, i, StackGrowsDown, Offset, MaxAlign);
}
if (RS && !RegInfo->hasFP(Fn)) {
int SFI = RS->getScavengingFrameIndex();
if (SFI >= 0)
AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
}
if (!RegInfo->targetHandlesStackFrameRounding() &&
(FFI->hasCalls() || FFI->hasVarSizedObjects() ||
(RegInfo->needsStackRealignment(Fn) &&
FFI->getObjectIndexEnd() != 0))) {
if (RegInfo->hasReservedCallFrame(Fn))
Offset += FFI->getMaxCallFrameSize();
unsigned AlignMask = std::max(TFI.getStackAlignment(),MaxAlign) - 1;
Offset = (Offset + AlignMask) & ~uint64_t(AlignMask);
}
FFI->setStackSize(Offset+TFI.getOffsetOfLocalArea());
FFI->setMaxAlignment(MaxAlign);
}
void PEI::insertPrologEpilogCode(MachineFunction &Fn) {
const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
TRI->emitPrologue(Fn);
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
if (!I->empty() && I->back().getDesc().isReturn())
TRI->emitEpilogue(Fn, *I);
}
}
void PEI::replaceFrameIndices(MachineFunction &Fn) {
if (!Fn.getFrameInfo()->hasStackObjects()) return;
const TargetMachine &TM = Fn.getTarget();
assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!");
const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
const TargetFrameInfo *TFI = TM.getFrameInfo();
bool StackGrowsDown =
TFI->getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
int FrameSetupOpcode = TRI.getCallFrameSetupOpcode();
int FrameDestroyOpcode = TRI.getCallFrameDestroyOpcode();
for (MachineFunction::iterator BB = Fn.begin(),
E = Fn.end(); BB != E; ++BB) {
int SPAdj = 0; if (RS) RS->enterBasicBlock(BB);
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
if (I->getOpcode() == TargetInstrInfo::DECLARE) {
++I;
continue;
}
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
int Size = I->getOperand(0).getImm();
if ((!StackGrowsDown && I->getOpcode() == FrameSetupOpcode) ||
(StackGrowsDown && I->getOpcode() == FrameDestroyOpcode))
Size = -Size;
SPAdj += Size;
MachineBasicBlock::iterator PrevI = BB->end();
if (I != BB->begin()) PrevI = prior(I);
TRI.eliminateCallFramePseudoInstr(Fn, *BB, I);
if (PrevI == BB->end())
I = BB->begin(); else
I = next(PrevI);
continue;
}
MachineInstr *MI = I;
bool DoIncr = true;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
if (MI->getOperand(i).isFI()) {
bool AtBeginning = (I == BB->begin());
if (!AtBeginning) --I;
TRI.eliminateFrameIndex(MI, SPAdj, RS);
if (AtBeginning) {
I = BB->begin();
DoIncr = false;
}
MI = 0;
break;
}
if (DoIncr && I != BB->end()) ++I;
if (RS && MI) RS->forward(MI);
}
assert(SPAdj == 0 && "Unbalanced call frame setup / destroy pairs?");
}
}