-STATISTIC(numSRReduced, "Number of CSR spills+restores reduced.");
-
-// Shrink Wrapping:
-static cl::opt<bool>
-ShrinkWrapping("shrink-wrap",
- cl::desc("Shrink wrap callee-saved register spills/restores"));
-
-// Shrink wrap only the specified function, a debugging aid.
-static cl::opt<std::string>
-ShrinkWrapFunc("shrink-wrap-func", cl::Hidden,
- cl::desc("Shrink wrap the specified function"),
- cl::value_desc("funcname"),
- cl::init(""));
-
-// Debugging level for shrink wrapping.
-enum ShrinkWrapDebugLevel {
- None, BasicInfo, Iterations, Details
-};
-
-static cl::opt<enum ShrinkWrapDebugLevel>
-ShrinkWrapDebugging("shrink-wrap-dbg", cl::Hidden,
- cl::desc("Print shrink wrapping debugging information"),
- cl::values(
- clEnumVal(None , "disable debug output"),
- clEnumVal(BasicInfo , "print basic DF sets"),
- clEnumVal(Iterations, "print SR sets for each iteration"),
- clEnumVal(Details , "print all DF sets"),
- clEnumValEnd));
-
-
-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 || ShrinkWrapFunc != "") {
- 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;
-
- DEBUG(MF = &Fn);
-
- // 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 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;
- clearAllSets();
- 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;
-
- // Map of MBBs to top level MachineLoops.
- DenseMap<MachineBasicBlock*, MachineLoop*> TLLoops;
-
- // Flag to control shrink wrapping per-function:
- // may choose to skip shrink wrapping for certain
- // functions.
- bool ShrinkWrapThisFunction;
-
-#ifndef NDEBUG
- // Machine function handle.
- MachineFunction* MF;
-
- // Flag indicating that the current function
- // has at least one "short" path in the machine
- // CFG from the entry block to an exit block.
- bool HasFastExitPath;
-#endif
-
- bool calculateSets(MachineFunction &Fn);
- bool calcAnticInOut(MachineBasicBlock* MBB);
- bool calcAvailInOut(MachineBasicBlock* MBB);
- void calculateAnticAvail(MachineFunction &Fn);
- bool addUsesForMEMERegion(MachineBasicBlock* MBB,
- SmallVector<MachineBasicBlock*, 4>& blks);
- bool addUsesForTopLevelLoops(SmallVector<MachineBasicBlock*, 4>& blks);
- bool calcSpillPlacements(MachineBasicBlock* MBB,
- SmallVector<MachineBasicBlock*, 4> &blks,
- CSRegBlockMap &prevSpills);
- bool calcRestorePlacements(MachineBasicBlock* MBB,
- SmallVector<MachineBasicBlock*, 4> &blks,
- CSRegBlockMap &prevRestores);
- 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 DFA sets, called before iterations.
- void clearAnticAvailSets();
- // Clear all sets constructed by shrink wrapping.
- void clearAllSets();
-
- // Initialize all shrink wrapping data.
- void initShrinkWrappingInfo();
-
- // 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;
- }
-
- MachineLoop* getTopLevelLoopParent(MachineLoop *LP) {
- if (LP == 0)
- return 0;
- MachineLoop* PLP = LP->getParentLoop();
- while (PLP) {
- LP = PLP;
- PLP = PLP->getParentLoop();
- }
- return LP;
- }
-
- // Propgate CSRs used in MBB to all MBBs of loop LP.
- void propagateUsesAroundLoop(MachineBasicBlock* MBB, MachineLoop* LP);
-
- // Convenience for recognizing return blocks.
- bool isReturnBlock(MachineBasicBlock* MBB) {
- return (MBB && !MBB->empty() && MBB->back().getDesc().isReturn());
- }
-
-#ifndef NDEBUG
- // Debugging methods.
-
- // Mark this function as having fast exit paths.
- void findFastExitPath();
-
- // Verify placement of spills/restores.
- void verifySpillRestorePlacement();
-
- std::string getBasicBlockName(const MachineBasicBlock* MBB);
- std::string stringifyCSRegSet(const CSRegSet& s);
- void dumpSet(const CSRegSet& s);
- void dumpUsed(MachineBasicBlock* MBB);
- void dumpAllUsed();
- void dumpSets(MachineBasicBlock* MBB);
- void dumpSets1(MachineBasicBlock* MBB);
- void dumpAllSets();
- void dumpSRSets();
-#endif
-
- };
- char PEI::ID = 0;
-}
-
-// Initialize shrink wrapping DFA sets, called before iterations.
-void PEI::clearAnticAvailSets() {
- AnticIn.clear();
- AnticOut.clear();
- AvailIn.clear();
- AvailOut.clear();
-}
-
-// Clear all sets constructed by shrink wrapping.
-void PEI::clearAllSets() {
- ReturnBlocks.clear();
- clearAnticAvailSets();
- UsedCSRegs.clear();
- CSRUsed.clear();
- TLLoops.clear();
- CSRSave.clear();
- CSRRestore.clear();
-}
-
-// Initialize all shrink wrapping data.
-void PEI::initShrinkWrappingInfo() {
- clearAllSets();
- EntryBlock = 0;
- HasFastExitPath = false;
- ShrinkWrapThisFunction = ShrinkWrapping;
- // DEBUG: enable or disable shrink wrapping for the current function
- // via --shrink-wrap-func=<funcname>.
-#ifndef NDEBUG
- if (ShrinkWrapFunc != "") {
- std::string MFName = MF->getFunction()->getName();
- ShrinkWrapThisFunction = (MFName == ShrinkWrapFunc);
- }
-#endif
-}