// This pass must be run after register allocation. After this pass is
// executed, it is illegal to construct MO_FrameIndex operands.
//
-// This pass implements a shrink wrapping variant of prolog/epilog insertion:
-// - Places callee saved register (CSR) spills and restores in the CFG to
-// tightly surround uses so that execution paths that do not use CSRs do not
-// pay the spill/restore penalty.
-//
-// - Avoiding placment of spills/restores in loops: if a CSR is used inside a
-// loop(nest), the spills are placed in the loop preheader, and restores are
-// placed in the loop exit nodes (the successors of the loop _exiting_ nodes).
-//
-// - Covering paths without CSR uses: e.g. if a restore is placed in a join
-// block, a matching spill is added to the end of all immediate predecessor
-// blocks that are not reached by a spill. Similarly for saves placed in
-// branch blocks.
-//
-// Shrink wrapping uses an analysis similar to the one in GVNPRE to determine
-// which basic blocks require callee-saved register save/restore code.
-//
-// This pass uses MachineDominators and MachineLoopInfo. Loop information
-// is used to prevent shrink wrapping of callee-saved register save/restore
-// code into loops.
+// This pass provides an optional shrink wrapping variant of prolog/epilog
+// insertion, enabled via --shrink-wrap. See ShrinkWrapping.cpp.
//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "shrink-wrap"
-
-#include "llvm/CodeGen/Passes.h"
+#include "PrologEpilogInserter.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/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/IndexedMap.h"
#include "llvm/ADT/STLExtras.h"
#include <climits>
-#include <sstream>
using namespace llvm;
-// Shrink Wrapping:
-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);
- }
-
- /// runOnMachineFunction - Insert prolog/epilog code and replace abstract
- /// frame indexes with appropriate references.
- ///
- bool runOnMachineFunction(MachineFunction &Fn) {
- const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
- RS = TRI->requiresRegisterScavenging(Fn) ? new RegScavenger() : NULL;
-
- // Get MachineModuleInfo so that we can track the construction of the
- // frame.
- if (MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>())
- Fn.getFrameInfo()->setMachineModuleInfo(MMI);
-
- // Allow the target machine to make some adjustments to the function
- // e.g. UsedPhysRegs before calculateCalleeSavedRegisters.
- TRI->processFunctionBeforeCalleeSavedScan(Fn, RS);
-
- // Scan the function for modified callee saved registers and insert spill
- // code for any callee saved registers that are modified. Also calculate
- // the MaxCallFrameSize and HasCalls variables for the function's frame
- // information and eliminates call frame pseudo instructions.
- calculateCalleeSavedRegisters(Fn);
-
- // Determine placement of CSR spill/restore code:
- // - with shrink wrapping, place spills and restores to tightly
- // enclose regions in the Machine CFG of the function where
- // they are used. Without shrink wrapping
- // - default (no shrink wrapping), place all spills in the
- // entry block, all restores in return blocks.
- placeCSRSpillsAndRestores(Fn);
-
- // Add the code to save and restore the callee saved registers
- insertCSRSpillsAndRestores(Fn);
-
- // Allow the target machine to make final modifications to the function
- // before the frame layout is finalized.
- TRI->processFunctionBeforeFrameFinalized(Fn);
-
- // Calculate actual frame offsets for all of the abstract stack objects...
- calculateFrameObjectOffsets(Fn);
-
- // Add prolog and epilog code to the function. This function is required
- // to align the stack frame as necessary for any stack variables or
- // called functions. Because of this, calculateCalleeSavedRegisters
- // must be called before this function in order to set the HasCalls
- // and MaxCallFrameSize variables.
- insertPrologEpilogCode(Fn);
-
- // Replace all MO_FrameIndex operands with physical register references
- // and actual offsets.
- //
- replaceFrameIndices(Fn);
-
- delete RS;
- return true;
- }
-
- private:
- RegScavenger *RS;
-
- // MinCSFrameIndex, MaxCSFrameIndex - Keeps the range of callee saved
- // stack frame indexes.
- unsigned MinCSFrameIndex, MaxCSFrameIndex;
-
- // Analysis info for spill/restore placement.
- // "CSR": "callee saved register".
-
- // CSRegSet contains indices into the Callee Saved Register Info
- // vector built by calculateCalleeSavedRegisters() and accessed
- // via MF.getFrameInfo()->getCalleeSavedInfo().
- typedef SparseBitVector<> CSRegSet;
-
- // CSRegBlockMap maps MachineBasicBlocks to sets of callee
- // saved register indices.
- typedef DenseMap<MachineBasicBlock*, CSRegSet> CSRegBlockMap;
-
- // Set and maps for computing CSR spill/restore placement:
- // used in function (UsedCSRegs)
- // used in a basic block (CSRUsed)
- // anticipatable in a basic block (Antic{In,Out})
- // available in a basic block (Avail{In,Out})
- // to be spilled at the entry to a basic block (CSRSave)
- // to be restored at the end of a basic block (CSRRestore)
-
- CSRegSet UsedCSRegs;
- CSRegBlockMap CSRUsed;
- CSRegBlockMap AnticIn, AnticOut;
- CSRegBlockMap AvailIn, AvailOut;
- CSRegBlockMap CSRSave;
- CSRegBlockMap CSRRestore;
-
- // Entry and return blocks of the current function.
- MachineBasicBlock* EntryBlock;
- SmallVector<MachineBasicBlock*, 4> ReturnBlocks;
-
- // Flag to control shrink wrapping per-function:
- // may choose to skip shrink wrapping for certain
- // functions.
- 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);
-
- // Initialize all shrink wrapping data.
- 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;
- }
-
- // Convienences for dealing with machine loops.
- 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;
- }
+char PEI::ID = 0;
- MachineLoop* getTopLevelLoopParent(MachineLoop *LP) {
- if (LP == 0)
- return 0;
- MachineLoop* PLP = LP->getParentLoop();
- while (PLP) {
- LP = PLP;
- PLP = PLP->getParentLoop();
- }
- return LP;
- }
-
-#ifndef NDEBUG
- // Debugging methods.
- 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;
-}
+static RegisterPass<PEI>
+X("prologepilog", "Prologue/Epilogue Insertion");
/// createPrologEpilogCodeInserter - This function returns a pass that inserts
/// prolog and epilog code, and eliminates abstract frame references.
///
FunctionPass *llvm::createPrologEpilogCodeInserter() { return new PEI(); }
-
-/// placeCSRSpillsAndRestores - determine which MBBs of the function
-/// need save, restore code for callee-saved registers by doing a DF analysis
-/// similar to the one used in code motion (GVNPRE). This produces maps of MBBs
-/// to sets of registers (CSRs) for saves and restores. MachineLoopInfo
-/// is used to ensure that CSR save/restore code is not placed inside loops.
-/// This function computes the maps of MBBs -> CSRs to spill and restore
-/// in CSRSave, CSRRestore.
-///
-/// If shrink wrapping is not being performed, place all spills in
-/// the entry block, all restores in return blocks. In this case,
-/// CSRSave has a single mapping, CSRRestore has mappings for each
-/// return block.
+/// runOnMachineFunction - Insert prolog/epilog code and replace abstract
+/// frame indexes with appropriate references.
///
-void PEI::placeCSRSpillsAndRestores(MachineFunction &Fn) {
-
-#ifndef NDEBUG
- DOUT << "Place CSR spills/restores for "
- << Fn.getFunction()->getName() << "\n";
-#endif
-
- initShrinkWrappingInfo();
-
- if (calculateSets(Fn))
- placeSpillsAndRestores(Fn);
-}
-
-/// calculateAnticAvail - helper for computing the data flow
-/// sets required for determining spill/restore placements.
-///
-void PEI::calculateAnticAvail(MachineFunction &Fn) {
-
- // Calulate Antic{In,Out} and Avail{In,Out} iteratively on the MCFG.
- 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;
-
- // AnticOut[MBB] = INTERSECT(AnticIn[S] for S in SUCC(MBB))
- 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;
- }
- // AnticIn[MBB] = CSRUsed[MBB] | AnticOut[MBB];
- CSRegSet prevAnticIn = AnticIn[MBB];
- AnticIn[MBB] = CSRUsed[MBB] | AnticOut[MBB];
- if (prevAnticIn |= AnticIn[MBB])
- changed = true;
-
- // AvailIn[MBB] = INTERSECT(AvailOut[S] for S in PRED(MBB))
- 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;
- }
- // AvailOut[MBB] = CSRUsed[MBB] | AvailIn[MBB];
- CSRegSet prevAvailOut = AvailOut[MBB];
- AvailOut[MBB] = CSRUsed[MBB] | AvailIn[MBB];
- if (prevAvailOut |= AvailOut[MBB])
- changed = true;
- }
- ++iterations;
- }
-
- // EXP
- 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
-}
-
-/// calculateSets - helper function for placeCSRSpillsAndRestores,
-/// collect the CSRs used in this function, develop the DF sets that
-/// describe the minimal regions in the Machine CFG around which spills,
-/// restores must be placed.
-///
-/// This function decides if shrink wrapping should actually be done:
-/// if all CSR uses are in the entry block, no shrink wrapping is possible,
-/// so ShrinkWrapping is turned off (for the current function) and the
-/// function returns false.
-///
-bool 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()) {
-#ifndef NDEBUG
- DOUT << Fn.getFunction()->getName()
- << " uses no callee-saved registers.\n";
-#endif
- return false;
- }
-
-#ifndef NDEBUG
- DOUT << "-----------------------------------------------------------\n";
-#endif
-
+bool PEI::runOnMachineFunction(MachineFunction &Fn) {
+ const Function* F = Fn.getFunction();
const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
- bool allCSRUsesInEntryBlock = true;
-
- // Initialize UsedCSRegs set, CSRUsed map.
- // At the same time, put entry block directly into
- // CSRSave, CSRRestore sets if any CSRs are used.
+ RS = TRI->requiresRegisterScavenging(Fn) ? new RegScavenger() : NULL;
+ FrameIndexVirtualScavenging = TRI->requiresFrameIndexScavenging(Fn);
+ FrameConstantRegMap.clear();
+
+ // Get MachineModuleInfo so that we can track the construction of the
+ // frame.
+ if (MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>())
+ Fn.getFrameInfo()->setMachineModuleInfo(MMI);
+
+ // Calculate the MaxCallFrameSize and HasCalls variables for the function's
+ // frame information. Also eliminates call frame pseudo instructions.
+ calculateCallsInformation(Fn);
+
+ // Allow the target machine to make some adjustments to the function
+ // e.g. UsedPhysRegs before calculateCalleeSavedRegisters.
+ TRI->processFunctionBeforeCalleeSavedScan(Fn, RS);
+
+ // Scan the function for modified callee saved registers and insert spill code
+ // for any callee saved registers that are modified.
+ calculateCalleeSavedRegisters(Fn);
+
+ // Determine placement of CSR spill/restore code:
+ // - with shrink wrapping, place spills and restores to tightly
+ // enclose regions in the Machine CFG of the function where
+ // they are used. Without shrink wrapping
+ // - default (no shrink wrapping), place all spills in the
+ // entry block, all restores in return blocks.
+ placeCSRSpillsAndRestores(Fn);
+
+ // Add the code to save and restore the callee saved registers
+ if (!F->hasFnAttr(Attribute::Naked))
+ insertCSRSpillsAndRestores(Fn);
+
+ // Allow the target machine to make final modifications to the function
+ // before the frame layout is finalized.
+ TRI->processFunctionBeforeFrameFinalized(Fn);
+
+ // Calculate actual frame offsets for all abstract stack objects...
+ calculateFrameObjectOffsets(Fn);
+
+ // Add prolog and epilog code to the function. This function is required
+ // to align the stack frame as necessary for any stack variables or
+ // called functions. Because of this, calculateCalleeSavedRegisters
+ // must be called before this function in order to set the HasCalls
+ // and MaxCallFrameSize variables.
+ if (!F->hasFnAttr(Attribute::Naked))
+ insertPrologEpilogCode(Fn);
+
+ // Replace all MO_FrameIndex operands with physical register references
+ // and actual offsets.
//
- // Quick exit option (not implemented):
- // Given N CSR uses in entry block,
- // revert to default behavior, skip the placement
- // step and put all saves in entry, restores in
- // return blocks.
-
- // Set up entry and return blocks.
- 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);
-
- // TODO -- check for a use of a CSR in each imm. successor of EntryBlock,
- // do not shrink wrap this function if this is the case.
-
- // If not shrink wrapping (this function) at this point, set bits in
- // CSR{Save,Restore}[] and UsedCSRegs, then return.
- 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;
- }
-
- // Walk instructions in all MBBs, create basic sets, choose
- // whether or not to shrink wrap this function.
- 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();
- // If instruction I reads or modifies Reg, add it to UsedCSRegs,
- // CSRUsed map for the current block.
- 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))) {
- // CSR Reg is defined/used in block MBB.
- UsedCSRegs.set(inx);
- CSRUsed[MBB].set(inx);
- // Short-circuit analysis for entry, return blocks:
- // if a CSR is used in the entry block, add it directly
- // to CSRSave[EntryBlock] and to CSRRestore[R] for R
- // in ReturnBlocks. Note CSR uses in non-entry blocks.
- 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 {
- // Not shrink wrapping => ensure saves/restores are correctly
- // added for entry, return blocks.
- 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
-
- // Early exit:
- // 1. Not asked to do shrink wrapping => just "place" all spills(restores)
- // in the entry(return) block(s), already done above.
- // 2. All CSR uses in entry block => same as case 1, but say we will
- // not shrink wrap the current function.
- ShrinkWrapThisFunction = (ShrinkWrapping &&
- ShrinkWrapThisFunction &&
- ! allCSRUsesInEntryBlock);
- if (! ShrinkWrapThisFunction) {
- return false;
- }
+ replaceFrameIndices(Fn);
- calculateAnticAvail(Fn);
+ // If register scavenging is needed, as we've enabled doing it as a
+ // post-pass, scavenge the virtual registers that frame index elimiation
+ // inserted.
+ if (TRI->requiresRegisterScavenging(Fn) && FrameIndexVirtualScavenging)
+ scavengeFrameVirtualRegs(Fn);
+ delete RS;
+ clearAllSets();
return true;
}
-/// moveSpillsOutOfLoops - helper for placeSpillsAndRestores() which
-/// relocates a spill from a subgraph in a loop to the loop preheader.
-/// Returns the MBB to which saves have been moved, or the given MBB
-/// if it is a branch point.
-///
-MachineBasicBlock* PEI::moveSpillsOutOfLoops(MachineFunction &Fn,
- MachineBasicBlock* MBB) {
- if (MBB == 0 || CSRSave[MBB].empty())
- return 0;
-
- // Block to which saves are moved.
- 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
- // Add CSRegSet from MBB to LPH, empty out MBB's CSRegSet.
- CSRSave[LPH] |= CSRSave[MBB];
- // If saves moved to entry block, add restores to returns.
- if (LPH == EntryBlock) {
- for (unsigned i = 0, e = ReturnBlocks.size(); i != e; ++i)
- CSRRestore[ReturnBlocks[i]] |= CSRSave[MBB];
- } else {
- // Remember where we moved the save so we can add
- // restores on successor paths if necessary.
- if (LPH->succ_size() > 1)
- DEST = LPH;
- }
- CSRSave[MBB].clear();
- } else if (MBB->succ_size() > 1)
- DEST = MBB;
- return DEST;
-}
-
-/// addRestoresForSBranchBlock - helper for placeSpillsAndRestores() which
-/// adds restores of CSRs saved in branch point MBBs to the front of any
-/// successor blocks connected to regions with no uses of the saved CSRs.
-///
-void PEI::addRestoresForSBranchBlock(MachineFunction &Fn,
- MachineBasicBlock* MBB) {
-
- if (MBB == 0 || CSRSave[MBB].empty() || MBB->succ_size() < 2)
- return;
-
- // Add restores of CSRs saved in branch point MBBs to the
- // front of any succ blocks flowing into regions that
- // have no uses of MBB's CSRs.
- 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;
- }
- }
- // Additional restores are needed for SUCC iff there is at least
- // one CSR use reachable from the successors of MBB and there
- // are no uses in or below SUCC.
- if (needsRestore && hasCSRUses) {
-#ifndef NDEBUG
- DOUT << "MBB " << getBasicBlockName(MBB)
- << " needs a restore on path to successor "
- << getBasicBlockName(SUCC) << "\n";
-#endif
- // Add restores to SUCC for all CSRs saved in MBB...
- CSRRestore[SUCC] = CSRSave[MBB];
- }
+#if 0
+void PEI::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ if (ShrinkWrapping || ShrinkWrapFunc != "") {
+ AU.addRequired<MachineLoopInfo>();
+ AU.addRequired<MachineDominatorTree>();
}
+ AU.addPreserved<MachineLoopInfo>();
+ AU.addPreserved<MachineDominatorTree>();
+ MachineFunctionPass::getAnalysisUsage(AU);
}
-
-/// moveRestoresOutOfLoops - helper for placeSpillsAndRestores() which
-/// relocates restores from a subgraph in a loop to the loop exit blocks.
-/// This function records the MBBs to which restores have been moved in
-/// SBLKS. If no restores are moved, SBLKS contains the input MBB if it
-/// is a join point in the Machine CFG.
-///
-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
- // Add CSRegSet from MBB to LPE, empty out MBB's CSRegSet.
- 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);
-}
-
-/// addSavesForRJoinBlocks - Add saves of CSRs restored in join point MBBs
-/// to the ends of any pred blocks that flow into MBB from regions that
-/// have no uses of MBB's CSRs.
-///
-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;
-
- // Walk back up in the CFG from the preds of MBB, look for
- // a block that uses any CSR that is restored in MBB.
- 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) {
- // Add saves to PRED for all CSRs restored in MBB...
-#ifndef NDEBUG
- DOUT << "MBB " << getBasicBlockName(MBB)
- << " needs a save on path from predecessor "
- << getBasicBlockName(PRED) << "\n";
-#endif
- CSRSave[PRED] = CSRRestore[MBB];
- }
- }
- }
- }
-}
-
-/// placeSpillsAndRestores - decide which MBBs need spills, restores
-/// of CSRs.
-///
-void PEI::placeSpillsAndRestores(MachineFunction &Fn) {
-
-#ifndef NDEBUG
- DOUT << "-----------------------------------------------------------\n";
-#endif
-
- // Calculate CSR{Save,Restore} using Antic, Avail on the Machine-CFG.
- for (MachineFunction::iterator MBBI = Fn.begin(), MBBE = Fn.end();
- MBBI != MBBE; ++MBBI) {
- MachineBasicBlock* MBB = MBBI;
- // Entry block saves are recorded in UsedCSRegs pass above.
- if (MBB != EntryBlock) {
- // Intersect (CSRegs - AnticIn[P]) for all predecessors P of MBB
- 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;
- // Handle self loop.
- if (PRED != MBB)
- anticInPreds &= (UsedCSRegs - AnticIn[PRED]);
- }
- }
- // CSRSave[MBB] = (AnticIn[MBB] - AvailIn[MBB]) & anticInPreds
- CSRSave[MBB] = (AnticIn[MBB] - AvailIn[MBB]) & anticInPreds;
-
- // Remove the CSRs that are saved in the entry block
- if (! CSRSave[MBB].empty() && ! CSRSave[EntryBlock].empty())
- CSRSave[MBB] = CSRSave[MBB] - CSRSave[EntryBlock];
-
- // Move saves inside loops to the preheaders of the outermost
- // containing loops, add restores to blocks reached by saves
- // placed at branch points where necessary.
- if (MachineBasicBlock* DESTBB = moveSpillsOutOfLoops(Fn, MBB)) {
- // Add restores to blocks reached by saves placed at branch
- // points where necessary.
- addRestoresForSBranchBlock(Fn, DESTBB);
- }
- }
-
-#ifndef NDEBUG
- if (! CSRSave[MBB].empty())
- DOUT << "SAVE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(CSRSave[MBB], Fn) << "\n";
-#endif
-
- // Compute CSRRestore, which may already be set for return blocks.
- if (! CSRRestore[MBB].empty() || MBB->pred_size() == 0)
- continue;
-
- // Intersect (CSRegs - AvailOut[S]) for all successors S of MBB
- 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;
- // Handle self loop.
- if (SUCC != MBB)
- availOutSucc &= (UsedCSRegs - AvailOut[SUCC]);
- }
- } else if (! CSRUsed[MBB].empty()) {
- // Take care of uses in return blocks (which have no successors).
- availOutSucc = UsedCSRegs;
- }
- // CSRRestore[MBB] = (AvailOut[MBB] - AnticOut[MBB]) & availOutSucc
- CSRRestore[MBB] = (AvailOut[MBB] - AnticOut[MBB]) & availOutSucc;
-
- // Remove the CSRs that are restored in the return blocks.
- // Lest this be confusing, note that:
- // CSRSave[EntryBlock] == CSRRestore[B] for all B in ReturnBlocks.
- if (! CSRRestore[MBB].empty() && ! CSRSave[EntryBlock].empty())
- CSRRestore[MBB] = CSRRestore[MBB] - CSRSave[EntryBlock];
-
- // Move restores inside loops to the exits of the outermost (top level)
- // containing loops.
- std::vector<MachineBasicBlock*> saveBlocks;
- moveRestoresOutOfLoops(Fn, MBB, saveBlocks);
-
- // Add saves of CSRs restored in join point MBBs to the ends
- // of any pred blocks that flow into MBB from regions that
- // have no uses of MBB's CSRs.
- 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
-}
-
-/// calculateCalleeSavedRegisters - Scan the function for modified callee saved
-/// registers. Also calculate the MaxCallFrameSize and HasCalls variables for
-/// the function's frame information and eliminates call frame pseudo
-/// instructions.
-///
-void PEI::calculateCalleeSavedRegisters(MachineFunction &Fn) {
+/// calculateCallsInformation - Calculate the MaxCallFrameSize and HasCalls
+/// variables for the function's frame information and eliminate call frame
+/// pseudo instructions.
+void PEI::calculateCallsInformation(MachineFunction &Fn) {
const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
- const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo();
+ MachineFrameInfo *FFI = Fn.getFrameInfo();
- // Get the callee saved register list...
- const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(&Fn);
+ unsigned MaxCallFrameSize = 0;
+ bool HasCalls = FFI->hasCalls();
// Get the function call frame set-up and tear-down instruction opcode
int FrameSetupOpcode = RegInfo->getCallFrameSetupOpcode();
int FrameDestroyOpcode = RegInfo->getCallFrameDestroyOpcode();
- // 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 and no call
- // frame setup/destroy pseudo instructions.
- if ((CSRegs == 0 || CSRegs[0] == 0) &&
- FrameSetupOpcode == -1 && FrameDestroyOpcode == -1)
+ // Early exit for targets which have no call frame setup/destroy pseudo
+ // instructions.
+ if (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 (Size > MaxCallFrameSize) MaxCallFrameSize = Size;
HasCalls = true;
FrameSDOps.push_back(I);
+ } else if (I->isInlineAsm()) {
+ // An InlineAsm might be a call; assume it is to get the stack frame
+ // aligned correctly for calls.
+ HasCalls = true;
}
- 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 call frames are not being included as part of the stack frame,
- // and there is no dynamic allocation (therefore referencing frame slots
- // off sp), leave the pseudo ops alone. We'll eliminate them later.
- if (RegInfo->hasReservedCallFrame(Fn) || RegInfo->hasFP(Fn))
+ for (std::vector<MachineBasicBlock::iterator>::iterator
+ i = FrameSDOps.begin(), e = FrameSDOps.end(); i != e; ++i) {
+ MachineBasicBlock::iterator I = *i;
+
+ // If call frames are not being included as part of the stack frame, and
+ // the target doesn't indicate otherwise, remove the call frame pseudos
+ // here. The sub/add sp instruction pairs are still inserted, but we don't
+ // need to track the SP adjustment for frame index elimination.
+ if (RegInfo->canSimplifyCallFramePseudos(Fn))
RegInfo->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
}
+}
+
- // Now figure out which *callee saved* registers are modified by the current
+/// calculateCalleeSavedRegisters - Scan the function for modified callee saved
+/// registers.
+void PEI::calculateCalleeSavedRegisters(MachineFunction &Fn) {
+ const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
+ const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo();
+ MachineFrameInfo *FFI = Fn.getFrameInfo();
+
+ // Get the callee saved register list...
+ const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(&Fn);
+
+ // 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 == 0 || CSRegs[0] == 0)
+ return;
+
+ // Figure out which *callee saved* registers are modified by the current
// function, thus needing to be saved and restored in the prolog/epilog.
- //
- const TargetRegisterClass* const *CSRegClasses =
+ 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)) {
- // If the reg is modified, save it!
+ // If the reg is modified, save it!
CSI.push_back(CalleeSavedInfo(Reg, CSRegClasses[i]));
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
return; // Early exit if no callee saved registers are modified!
unsigned NumFixedSpillSlots;
- const std::pair<unsigned,int> *FixedSpillSlots =
+ const TargetFrameInfo::SpillSlot *FixedSpillSlots =
TFI->getCalleeSavedSpillSlots(NumFixedSpillSlots);
// Now that we know which registers need to be saved and restored, allocate
// stack slots for them.
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- unsigned Reg = CSI[i].getReg();
- const TargetRegisterClass *RC = CSI[i].getRegClass();
+ for (std::vector<CalleeSavedInfo>::iterator
+ I = CSI.begin(), E = CSI.end(); I != E; ++I) {
+ unsigned Reg = I->getReg();
+ const TargetRegisterClass *RC = I->getRegClass();
+
+ int FrameIdx;
+ if (RegInfo->hasReservedSpillSlot(Fn, Reg, FrameIdx)) {
+ I->setFrameIdx(FrameIdx);
+ continue;
+ }
// Check to see if this physreg must be spilled to a particular stack slot
// on this target.
- const std::pair<unsigned,int> *FixedSlot = FixedSpillSlots;
+ const TargetFrameInfo::SpillSlot *FixedSlot = FixedSpillSlots;
while (FixedSlot != FixedSpillSlots+NumFixedSpillSlots &&
- FixedSlot->first != Reg)
+ FixedSlot->Reg != Reg)
++FixedSlot;
- int FrameIdx;
- if (FixedSlot == FixedSpillSlots+NumFixedSpillSlots) {
+ if (FixedSlot == FixedSpillSlots + NumFixedSpillSlots) {
// Nope, just spill it anywhere convenient.
unsigned Align = RC->getAlignment();
unsigned StackAlign = TFI->getStackAlignment();
- // We may not be able to sastify the desired alignment specification of
- // the TargetRegisterClass if the stack alignment is smaller.
- // Use the min.
+
+ // We may not be able to satisfy the desired alignment specification of
+ // the TargetRegisterClass if the stack alignment is smaller. Use the
+ // min.
Align = std::min(Align, StackAlign);
- FrameIdx = FFI->CreateStackObject(RC->getSize(), Align);
+ FrameIdx = FFI->CreateStackObject(RC->getSize(), Align, true);
if ((unsigned)FrameIdx < MinCSFrameIndex) MinCSFrameIndex = FrameIdx;
if ((unsigned)FrameIdx > MaxCSFrameIndex) MaxCSFrameIndex = FrameIdx;
} else {
// Spill it to the stack where we must.
- FrameIdx = FFI->CreateFixedObject(RC->getSize(), FixedSlot->second);
+ FrameIdx = FFI->CreateFixedObject(RC->getSize(), FixedSlot->Offset,
+ true, false);
}
- CSI[i].setFrameIdx(FrameIdx);
+
+ I->setFrameIdx(FrameIdx);
}
FFI->setCalleeSavedInfo(CSI);
MachineFrameInfo *FFI = Fn.getFrameInfo();
const std::vector<CalleeSavedInfo> &CSI = FFI->getCalleeSavedInfo();
+ FFI->setCalleeSavedInfoValid(true);
+
// Early exit if no callee saved registers are modified!
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
-
- // Insert spills.
- 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) {
- // Spill using target interface.
- I = MBB->begin();
- if (!TII.spillCalleeSavedRegisters(*MBB, I, CSI)) {
- for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- // Add the callee-saved register as live-in. It's killed at the spill.
- MBB->addLiveIn(CSI[i].getReg());
-
- // Insert the spill to the stack frame.
- 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 has no uses of CSRs being saved, this means saves
- // must be inserted at the _end_.
- 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();
- }
-
- // When shrink wrapping, use stack slot stores/loads.
- for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
+ if (! ShrinkWrapThisFunction) {
+ // Spill using target interface.
+ I = EntryBlock->begin();
+ if (!TII.spillCalleeSavedRegisters(*EntryBlock, I, CSI)) {
+ for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
// Add the callee-saved register as live-in.
// It's killed at the spill.
- MBB->addLiveIn(blockCSI[i].getReg());
+ EntryBlock->addLiveIn(CSI[i].getReg());
// Insert the spill to the stack frame.
- TII.storeRegToStackSlot(*MBB, I, blockCSI[i].getReg(),
- true,
- blockCSI[i].getFrameIdx(),
- blockCSI[i].getRegClass());
+ TII.storeRegToStackSlot(*EntryBlock, I, CSI[i].getReg(), true,
+ CSI[i].getFrameIdx(), CSI[i].getRegClass());
}
}
- }
- // Use CSRRestore to add code to restore the callee-saved registers in
- // each block.
- 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) {
- // Restore using target interface.
+ // Restore using target interface.
+ for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri) {
+ MachineBasicBlock* MBB = ReturnBlocks[ri];
I = MBB->end(); --I;
// Skip over all terminator instructions, which are part of the return
}
}
}
- } else {
-#ifndef NDEBUG
- DOUT << "CSRRestore[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(restore, Fn) << "\n";
-#endif
+ }
+ return;
+ }
- 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");
+ // Insert spills.
+ std::vector<CalleeSavedInfo> blockCSI;
+ for (CSRegBlockMap::iterator BI = CSRSave.begin(),
+ BE = CSRSave.end(); BI != BE; ++BI) {
+ MachineBasicBlock* MBB = BI->first;
+ CSRegSet save = BI->second;
- // If MBB uses no CSRs but has restores, this means
- // it must have restores inserted at the _beginning_.
- // N.B. -- not necessary if edge splitting done.
- if (MBB->empty() || ! CSRUsed[MBB].intersects(restore)) {
- I = MBB->begin();
- } else {
- I = MBB->end();
- --I;
-
- // EXP iff spill/restore implemented with push/pop:
- // append restore to block unless it ends in a
- // barrier terminator instruction.
-
- // Skip over all terminator instructions, which are part of the
- // return sequence.
- if (I->getDesc().isCall()) {
- ++I;
- } else {
- MachineBasicBlock::iterator I2 = I;
- while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator())
- I = I2;
- }
- }
+ if (save.empty())
+ continue;
- bool AtStart = I == MBB->begin();
- MachineBasicBlock::iterator BeforeI = I;
- if (!AtStart)
- --BeforeI;
+ 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");
+
+ I = MBB->begin();
+
+ // When shrink wrapping, use stack slot stores/loads.
+ for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
+ // Add the callee-saved register as live-in.
+ // It's killed at the spill.
+ MBB->addLiveIn(blockCSI[i].getReg());
+
+ // Insert the spill to the stack frame.
+ 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;
-#ifndef NDEBUG
- if (! MBB->empty() && ! CSRUsed[MBB].intersects(restore)) {
- MachineInstr* MI = BeforeI;
- DOUT << "adding restore after ";
- DEBUG(MI->dump());
+ if (restore.empty())
+ continue;
+
+ 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 is empty and needs restores, insert at the _beginning_.
+ if (MBB->empty()) {
+ I = MBB->begin();
+ } else {
+ I = MBB->end();
+ --I;
+
+ // Skip over all terminator instructions, which are part of the
+ // return sequence.
+ if (! I->getDesc().isTerminator()) {
+ ++I;
} else {
- DOUT << "adding restore to beginning of "
- << getBasicBlockName(MBB) << "\n";
+ MachineBasicBlock::iterator I2 = I;
+ while (I2 != MBB->begin() && (--I2)->getDesc().isTerminator())
+ I = I2;
}
-#endif
+ }
- // Restore all registers immediately before the return and any
- // terminators that preceed it.
- 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!");
- // Insert in reverse order. loadRegFromStackSlot can insert
- // multiple instructions.
- if (AtStart)
- I = MBB->begin();
- else {
- I = BeforeI;
- ++I;
- }
+ bool AtStart = I == MBB->begin();
+ MachineBasicBlock::iterator BeforeI = I;
+ if (!AtStart)
+ --BeforeI;
+
+ // Restore all registers immediately before the return and any
+ // terminators that preceed it.
+ 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!");
+ // Insert in reverse order. loadRegFromStackSlot can insert
+ // multiple instructions.
+ if (AtStart)
+ I = MBB->begin();
+ else {
+ I = BeforeI;
+ ++I;
}
}
}
AdjustStackOffset(MachineFrameInfo *FFI, int FrameIdx,
bool StackGrowsDown, int64_t &Offset,
unsigned &MaxAlign) {
- // If stack grows down, we need to add size of find the lowest address of the
- // object.
+ // If the stack grows down, add the object size to find the lowest address.
if (StackGrowsDown)
Offset += FFI->getObjectSize(FrameIdx);
// Loop over all of the stack objects, assigning sequential addresses...
MachineFrameInfo *FFI = Fn.getFrameInfo();
- unsigned MaxAlign = FFI->getMaxAlignment();
-
// Start at the beginning of the local area.
// The Offset is the distance from the stack top in the direction
// of stack growth -- so it's always nonnegative.
- int64_t Offset = TFI.getOffsetOfLocalArea();
+ int LocalAreaOffset = TFI.getOffsetOfLocalArea();
if (StackGrowsDown)
- Offset = -Offset;
- assert(Offset >= 0
+ LocalAreaOffset = -LocalAreaOffset;
+ assert(LocalAreaOffset >= 0
&& "Local area offset should be in direction of stack growth");
+ int64_t Offset = LocalAreaOffset;
// If there are fixed sized objects that are preallocated in the local area,
// non-fixed objects can't be allocated right at the start of local area.
Offset += FFI->getObjectSize(i);
unsigned Align = FFI->getObjectAlignment(i);
- // If the alignment of this object is greater than that of the stack,
- // then increase the stack alignment to match.
- MaxAlign = std::max(MaxAlign, Align);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
int MaxCSFI = MaxCSFrameIndex, MinCSFI = MinCSFrameIndex;
for (int i = MaxCSFI; i >= MinCSFI ; --i) {
unsigned Align = FFI->getObjectAlignment(i);
- // If the alignment of this object is greater than that of the stack,
- // then increase the stack alignment to match.
- MaxAlign = std::max(MaxAlign, Align);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
}
}
+ unsigned MaxAlign = FFI->getMaxAlignment();
+
// Make sure the special register scavenging spill slot is closest to the
// frame pointer if a frame pointer is required.
const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
- if (RS && RegInfo->hasFP(Fn)) {
+ if (RS && RegInfo->hasFP(Fn) && !RegInfo->needsStackRealignment(Fn)) {
int SFI = RS->getScavengingFrameIndex();
if (SFI >= 0)
AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
// Make sure the special register scavenging spill slot is closest to the
// stack pointer.
- if (RS && !RegInfo->hasFP(Fn)) {
+ if (RS && (!RegInfo->hasFP(Fn) || RegInfo->needsStackRealignment(Fn))) {
int SFI = RS->getScavengingFrameIndex();
if (SFI >= 0)
AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
}
- // Round up the size to a multiple of the alignment, but only if there are
- // calls or alloca's in the function. This ensures that any calls to
- // subroutines have their stack frames suitable aligned.
- // Also do this if we need runtime alignment of the stack. In this case
- // offsets will be relative to SP not FP; round up the stack size so this
- // works.
- if (!RegInfo->targetHandlesStackFrameRounding() &&
- (FFI->hasCalls() || FFI->hasVarSizedObjects() ||
- (RegInfo->needsStackRealignment(Fn) &&
- FFI->getObjectIndexEnd() != 0))) {
+ if (!RegInfo->targetHandlesStackFrameRounding()) {
// If we have reserved argument space for call sites in the function
// immediately on entry to the current function, count it as part of the
// overall stack size.
- if (RegInfo->hasReservedCallFrame(Fn))
+ if (FFI->hasCalls() && RegInfo->hasReservedCallFrame(Fn))
Offset += FFI->getMaxCallFrameSize();
- unsigned AlignMask = std::max(TFI.getStackAlignment(),MaxAlign) - 1;
+ // Round up the size to a multiple of the alignment. If the function has
+ // any calls or alloca's, align to the target's StackAlignment value to
+ // ensure that the callee's frame or the alloca data is suitably aligned;
+ // otherwise, for leaf functions, align to the TransientStackAlignment
+ // value.
+ unsigned StackAlign;
+ if (FFI->hasCalls() || FFI->hasVarSizedObjects() ||
+ (RegInfo->needsStackRealignment(Fn) && FFI->getObjectIndexEnd() != 0))
+ StackAlign = TFI.getStackAlignment();
+ else
+ StackAlign = TFI.getTransientStackAlignment();
+ // 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);
}
// Update frame info to pretend that this is part of the stack...
- FFI->setStackSize(Offset+TFI.getOffsetOfLocalArea());
-
- // Remember the required stack alignment in case targets need it to perform
- // dynamic stack alignment.
- FFI->setMaxAlignment(MaxAlign);
+ FFI->setStackSize(Offset - LocalAreaOffset);
}
for (MachineFunction::iterator BB = Fn.begin(),
E = Fn.end(); BB != E; ++BB) {
int SPAdj = 0; // SP offset due to call frame setup / destroy.
- if (RS) RS->enterBasicBlock(BB);
+ if (RS && !FrameIndexVirtualScavenging) RS->enterBasicBlock(BB);
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
- if (I->getOpcode() == TargetInstrInfo::DECLARE) {
- // Ignore it.
- ++I;
- continue;
- }
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
if (PrevI == BB->end())
I = BB->begin(); // The replaced instr was the first in the block.
else
- I = next(PrevI);
+ I = llvm::next(PrevI);
continue;
}
// If this instruction has a FrameIndex operand, we need to
// use that target machine register info object to eliminate
// it.
-
- TRI.eliminateFrameIndex(MI, SPAdj, RS);
+ TargetRegisterInfo::FrameIndexValue Value;
+ unsigned VReg =
+ TRI.eliminateFrameIndex(MI, SPAdj, &Value,
+ FrameIndexVirtualScavenging ? NULL : RS);
+ if (VReg) {
+ assert (FrameIndexVirtualScavenging &&
+ "Not scavenging, but virtual returned from "
+ "eliminateFrameIndex()!");
+ FrameConstantRegMap[VReg] = FrameConstantEntry(Value, SPAdj);
+ }
// Reset the iterator if we were at the beginning of the BB.
if (AtBeginning) {
if (DoIncr && I != BB->end()) ++I;
// Update register states.
- if (RS && MI) RS->forward(MI);
+ if (RS && !FrameIndexVirtualScavenging && MI) RS->forward(MI);
}
assert(SPAdj == 0 && "Unbalanced call frame setup / destroy pairs?");
}
}
+
+/// findLastUseReg - find the killing use of the specified register within
+/// the instruciton range. Return the operand number of the kill in Operand.
+static MachineBasicBlock::iterator
+findLastUseReg(MachineBasicBlock::iterator I, MachineBasicBlock::iterator ME,
+ unsigned Reg) {
+ // Scan forward to find the last use of this virtual register
+ for (++I; I != ME; ++I) {
+ MachineInstr *MI = I;
+ bool isDefInsn = false;
+ bool isKillInsn = false;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
+ if (MI->getOperand(i).isReg()) {
+ unsigned OpReg = MI->getOperand(i).getReg();
+ if (OpReg == 0 || !TargetRegisterInfo::isVirtualRegister(OpReg))
+ continue;
+ assert (OpReg == Reg
+ && "overlapping use of scavenged index register!");
+ // If this is the killing use, we have a candidate.
+ if (MI->getOperand(i).isKill())
+ isKillInsn = true;
+ else if (MI->getOperand(i).isDef())
+ isDefInsn = true;
+ }
+ if (isKillInsn && !isDefInsn)
+ return I;
+ }
+ // If we hit the end of the basic block, there was no kill of
+ // the virtual register, which is wrong.
+ assert (0 && "scavenged index register never killed!");
+ return ME;
+}
+
+/// scavengeFrameVirtualRegs - Replace all frame index virtual registers
+/// with physical registers. Use the register scavenger to find an
+/// appropriate register to use.
+void PEI::scavengeFrameVirtualRegs(MachineFunction &Fn) {
+ // Run through the instructions and find any virtual registers.
+ for (MachineFunction::iterator BB = Fn.begin(),
+ E = Fn.end(); BB != E; ++BB) {
+ RS->enterBasicBlock(BB);
+
+ // FIXME: The logic flow in this function is still too convoluted.
+ // It needs a cleanup refactoring. Do that in preparation for tracking
+ // more than one scratch register value and using ranges to find
+ // available scratch registers.
+ unsigned CurrentVirtReg = 0;
+ unsigned CurrentScratchReg = 0;
+ bool havePrevValue = false;
+ TargetRegisterInfo::FrameIndexValue PrevValue(0,0);
+ TargetRegisterInfo::FrameIndexValue Value(0,0);
+ MachineInstr *PrevLastUseMI = NULL;
+ unsigned PrevLastUseOp = 0;
+ bool trackingCurrentValue = false;
+ int SPAdj = 0;
+
+ // The instruction stream may change in the loop, so check BB->end()
+ // directly.
+ for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
+ MachineInstr *MI = I;
+ bool isDefInsn = false;
+ bool isKillInsn = false;
+ bool clobbersScratchReg = false;
+ bool DoIncr = true;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ if (MI->getOperand(i).isReg()) {
+ MachineOperand &MO = MI->getOperand(i);
+ unsigned Reg = MO.getReg();
+ if (Reg == 0)
+ continue;
+ if (!TargetRegisterInfo::isVirtualRegister(Reg)) {
+ // If we have a previous scratch reg, check and see if anything
+ // here kills whatever value is in there.
+ if (Reg == CurrentScratchReg) {
+ if (MO.isUse()) {
+ // Two-address operands implicitly kill
+ if (MO.isKill() || MI->isRegTiedToDefOperand(i))
+ clobbersScratchReg = true;
+ } else {
+ assert (MO.isDef());
+ clobbersScratchReg = true;
+ }
+ }
+ continue;
+ }
+ // If this is a def, remember that this insn defines the value.
+ // This lets us properly consider insns which re-use the scratch
+ // register, such as r2 = sub r2, #imm, in the middle of the
+ // scratch range.
+ if (MO.isDef())
+ isDefInsn = true;
+
+ // Have we already allocated a scratch register for this virtual?
+ if (Reg != CurrentVirtReg) {
+ // When we first encounter a new virtual register, it
+ // must be a definition.
+ assert(MI->getOperand(i).isDef() &&
+ "frame index virtual missing def!");
+ // We can't have nested virtual register live ranges because
+ // there's only a guarantee of one scavenged register at a time.
+ assert (CurrentVirtReg == 0 &&
+ "overlapping frame index virtual registers!");
+
+ // If the target gave us information about what's in the register,
+ // we can use that to re-use scratch regs.
+ DenseMap<unsigned, FrameConstantEntry>::iterator Entry =
+ FrameConstantRegMap.find(Reg);
+ trackingCurrentValue = Entry != FrameConstantRegMap.end();
+ if (trackingCurrentValue) {
+ SPAdj = (*Entry).second.second;
+ Value = (*Entry).second.first;
+ } else {
+ SPAdj = 0;
+ Value.first = 0;
+ Value.second = 0;
+ }
+
+ // If the scratch register from the last allocation is still
+ // available, see if the value matches. If it does, just re-use it.
+ if (trackingCurrentValue && havePrevValue && PrevValue == Value) {
+ // FIXME: This assumes that the instructions in the live range
+ // for the virtual register are exclusively for the purpose
+ // of populating the value in the register. That's reasonable
+ // for these frame index registers, but it's still a very, very
+ // strong assumption. rdar://7322732. Better would be to
+ // explicitly check each instruction in the range for references
+ // to the virtual register. Only delete those insns that
+ // touch the virtual register.
+
+ // Find the last use of the new virtual register. Remove all
+ // instruction between here and there, and update the current
+ // instruction to reference the last use insn instead.
+ MachineBasicBlock::iterator LastUseMI =
+ findLastUseReg(I, BB->end(), Reg);
+
+ // Remove all instructions up 'til the last use, since they're
+ // just calculating the value we already have.
+ BB->erase(I, LastUseMI);
+ I = LastUseMI;
+
+ // Extend the live range of the scratch register
+ PrevLastUseMI->getOperand(PrevLastUseOp).setIsKill(false);
+ RS->setUsed(CurrentScratchReg);
+ CurrentVirtReg = Reg;
+
+ // We deleted the instruction we were scanning the operands of.
+ // Jump back to the instruction iterator loop. Don't increment
+ // past this instruction since we updated the iterator already.
+ DoIncr = false;
+ break;
+ }
+
+ // Scavenge a new scratch register
+ CurrentVirtReg = Reg;
+ const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(Reg);
+ CurrentScratchReg = RS->FindUnusedReg(RC);
+ if (CurrentScratchReg == 0)
+ // No register is "free". Scavenge a register.
+ CurrentScratchReg = RS->scavengeRegister(RC, I, SPAdj);
+
+ PrevValue = Value;
+ }
+ // replace this reference to the virtual register with the
+ // scratch register.
+ assert (CurrentScratchReg && "Missing scratch register!");
+ MI->getOperand(i).setReg(CurrentScratchReg);
+
+ if (MI->getOperand(i).isKill()) {
+ isKillInsn = true;
+ PrevLastUseOp = i;
+ PrevLastUseMI = MI;
+ }
+ }
+ }
+ // If this is the last use of the scratch, stop tracking it. The
+ // last use will be a kill operand in an instruction that does
+ // not also define the scratch register.
+ if (isKillInsn && !isDefInsn) {
+ CurrentVirtReg = 0;
+ havePrevValue = trackingCurrentValue;
+ }
+ // Similarly, notice if instruction clobbered the value in the
+ // register we're tracking for possible later reuse. This is noted
+ // above, but enforced here since the value is still live while we
+ // process the rest of the operands of the instruction.
+ if (clobbersScratchReg) {
+ havePrevValue = false;
+ CurrentScratchReg = 0;
+ }
+ if (DoIncr) {
+ RS->forward(I);
+ ++I;
+ }
+ }
+ }
+}
projects / oota-llvm.git / blobdiff