// 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"
+#define DEBUG_TYPE "pei"
+#include "PrologEpilogInserter.h"
+#include "llvm/InlineAsm.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/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
-#include "llvm/Target/TargetFrameInfo.h"
+#include "llvm/Target/TargetFrameLowering.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 "llvm/ADT/IndexedMap.h"
+#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/STLExtras.h"
#include <climits>
-#include <sstream>
using namespace llvm;
-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;
- }
+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;
- }
-
- // 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;
-#ifndef NDEBUG
- HasFastExitPath = false;
-#endif
- 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
-}
+INITIALIZE_PASS_BEGIN(PEI, "prologepilog",
+ "Prologue/Epilogue Insertion", false, false)
+INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
+INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
+INITIALIZE_PASS_END(PEI, "prologepilog",
+ "Prologue/Epilogue Insertion", false, false)
+STATISTIC(NumVirtualFrameRegs, "Number of virtual frame regs encountered");
+STATISTIC(NumScavengedRegs, "Number of frame index regs scavenged");
+STATISTIC(NumBytesStackSpace,
+ "Number of bytes used for stack in all functions");
/// 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) {
-
- initShrinkWrappingInfo();
+bool PEI::runOnMachineFunction(MachineFunction &Fn) {
+ const Function* F = Fn.getFunction();
+ const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
+ const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering();
+
+ RS = TRI->requiresRegisterScavenging(Fn) ? new RegScavenger() : NULL;
+ FrameIndexVirtualScavenging = TRI->requiresFrameIndexScavenging(Fn);
+
+ // Calculate the MaxCallFrameSize and AdjustsStack 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.
+ TFI->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 shink wrapping (default), 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.
+ TFI->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 AdjustsStack
+ // and MaxCallFrameSize variables.
+ if (!F->hasFnAttr(Attribute::Naked))
+ insertPrologEpilogCode(Fn);
+
+ // Replace all MO_FrameIndex operands with physical register references
+ // and actual offsets.
+ //
+ replaceFrameIndices(Fn);
- DEBUG(if (ShrinkWrapThisFunction) {
- DOUT << "Place CSR spills/restores for "
- << MF->getFunction()->getName() << "\n";
- });
+ // 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);
- if (calculateSets(Fn))
- placeSpillsAndRestores(Fn);
+ delete RS;
+ clearAllSets();
+ return true;
}
-/// calcAnticInOut - calculate the anticipated in/out reg sets
-/// for the given MBB by looking forward in the MCFG at MBB's
-/// successors.
-///
-bool PEI::calcAnticInOut(MachineBasicBlock* MBB) {
- bool changed = false;
-
- // AnticOut[MBB] = INTERSECT(AnticIn[S] for S in SUCCESSORS(MBB))
- SmallVector<MachineBasicBlock*, 4> successors;
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock* SUCC = *SI;
- if (SUCC != MBB)
- successors.push_back(SUCC);
- }
-
- unsigned i = 0, e = successors.size();
- if (i != e) {
- CSRegSet prevAnticOut = AnticOut[MBB];
- MachineBasicBlock* SUCC = successors[i];
-
- AnticOut[MBB] = AnticIn[SUCC];
- for (++i; i != e; ++i) {
- SUCC = successors[i];
- AnticOut[MBB] &= AnticIn[SUCC];
- }
- if (prevAnticOut != AnticOut[MBB])
- changed = true;
+#if 0
+void PEI::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ if (ShrinkWrapping || ShrinkWrapFunc != "") {
+ AU.addRequired<MachineLoopInfo>();
+ AU.addRequired<MachineDominatorTree>();
}
-
- // AnticIn[MBB] = UNION(CSRUsed[MBB], AnticOut[MBB]);
- CSRegSet prevAnticIn = AnticIn[MBB];
- AnticIn[MBB] = CSRUsed[MBB] | AnticOut[MBB];
- if (prevAnticIn |= AnticIn[MBB])
- changed = true;
- return changed;
+ AU.addPreserved<MachineLoopInfo>();
+ AU.addPreserved<MachineDominatorTree>();
+ MachineFunctionPass::getAnalysisUsage(AU);
}
+#endif
-/// calcAvailInOut - calculate the available in/out reg sets
-/// for the given MBB by looking backward in the MCFG at MBB's
-/// predecessors.
-///
-bool PEI::calcAvailInOut(MachineBasicBlock* MBB) {
- bool changed = false;
-
- // AvailIn[MBB] = INTERSECT(AvailOut[P] for P in PREDECESSORS(MBB))
- SmallVector<MachineBasicBlock*, 4> predecessors;
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- MachineBasicBlock* PRED = *PI;
- if (PRED != MBB)
- predecessors.push_back(PRED);
- }
-
- unsigned i = 0, e = predecessors.size();
- if (i != e) {
- CSRegSet prevAvailIn = AvailIn[MBB];
- MachineBasicBlock* PRED = predecessors[i];
-
- AvailIn[MBB] = AvailOut[PRED];
- for (++i; i != e; ++i) {
- PRED = predecessors[i];
- AvailIn[MBB] &= AvailOut[PRED];
- }
- if (prevAvailIn != AvailIn[MBB])
- changed = true;
- }
-
- // AvailOut[MBB] = UNION(CSRUsed[MBB], AvailIn[MBB]);
- CSRegSet prevAvailOut = AvailOut[MBB];
- AvailOut[MBB] = CSRUsed[MBB] | AvailIn[MBB];
- if (prevAvailOut |= AvailOut[MBB])
- changed = true;
- return changed;
-}
+/// calculateCallsInformation - Calculate the MaxCallFrameSize and AdjustsStack
+/// 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 TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
+ const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering();
+ MachineFrameInfo *MFI = Fn.getFrameInfo();
-/// calculateAnticAvail - build the sets anticipated and available
-/// registers in the MCFG of the current function iteratively,
-/// doing a combined forward and backward analysis.
-///
-void PEI::calculateAnticAvail(MachineFunction &Fn) {
- // Initialize data flow sets.
- clearAnticAvailSets();
-
- // Calulate Antic{In,Out} and Avail{In,Out} iteratively on the MCFG.
- bool changed = true;
- unsigned iterations = 0;
- while (changed) {
- changed = false;
- ++iterations;
- for (MachineFunction::iterator MBBI = Fn.begin(), MBBE = Fn.end();
- MBBI != MBBE; ++MBBI) {
- MachineBasicBlock* MBB = MBBI;
-
- // Calculate anticipated in, out regs at MBB from
- // anticipated at successors of MBB.
- changed |= calcAnticInOut(MBB);
-
- // Calculate available in, out regs at MBB from
- // available at predecessors of MBB.
- changed |= calcAvailInOut(MBB);
- }
- }
+ unsigned MaxCallFrameSize = 0;
+ bool AdjustsStack = MFI->adjustsStack();
- DEBUG(if (ShrinkWrapDebugging >= Details) {
- DOUT << "-----------------------------------------------------------\n";
- DOUT << " Antic/Avail Sets:\n";
- DOUT << "-----------------------------------------------------------\n";
- DOUT << "iterations = " << iterations << "\n";
- DOUT << "-----------------------------------------------------------\n";
- DOUT << "MBB | USED | 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;
- dumpSets(MBB);
- }
- DOUT << "-----------------------------------------------------------\n";
- });
-}
+ // Get the function call frame set-up and tear-down instruction opcode
+ int FrameSetupOpcode = TII.getCallFrameSetupOpcode();
+ int FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
-/// propagateUsesAroundLoop - copy used register info from MBB to all blocks
-/// of the loop given by LP and its parent loops. This prevents spills/restores
-/// from being placed in the bodies of loops.
-///
-void PEI::propagateUsesAroundLoop(MachineBasicBlock* MBB, MachineLoop* LP) {
- if (! MBB || !LP)
+ // Early exit for targets which have no call frame setup/destroy pseudo
+ // instructions.
+ if (FrameSetupOpcode == -1 && FrameDestroyOpcode == -1)
return;
- std::vector<MachineBasicBlock*> loopBlocks = LP->getBlocks();
- for (unsigned i = 0, e = loopBlocks.size(); i != e; ++i) {
- MachineBasicBlock* LBB = loopBlocks[i];
- if (LBB == MBB)
- continue;
- if (CSRUsed[LBB].contains(CSRUsed[MBB]))
- continue;
- CSRUsed[LBB] |= CSRUsed[MBB];
- }
-}
-
-/// calculateSets - collect the CSRs used in this function, compute
-/// the DF sets that describe the initial minimal regions in the
-/// Machine CFG around which CSR spills and restores must be placed.
-///
-/// Additionally, this function decides if shrink wrapping should
-/// be disabled for the current function, checking the following:
-/// 1. the current function has more than 500 MBBs: heuristic limit
-/// on function size to reduce compile time impact of the current
-/// iterative algorithm.
-/// 2. all CSRs are used in the entry block.
-/// 3. all CSRs are used in all immediate successors of the entry block.
-/// 4. all CSRs are used in a subset of blocks, each of which dominates
-/// all return blocks. These blocks, taken as a subgraph of the MCFG,
-/// are equivalent to the entry block since all execution paths pass
-/// through them.
-///
-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()) {
- DEBUG(if (ShrinkWrapThisFunction)
- DOUT << "DISABLED: " << Fn.getFunction()->getName()
- << ": uses no callee-saved registers\n");
- return false;
- }
-
- // Save refs to entry and return blocks.
- EntryBlock = Fn.begin();
- for (MachineFunction::iterator MBB = Fn.begin(), E = Fn.end();
- MBB != E; ++MBB)
- if (isReturnBlock(MBB))
- ReturnBlocks.push_back(MBB);
-
- // Determine if this function has fast exit paths.
- DEBUG(if (ShrinkWrapThisFunction)
- findFastExitPath());
-
- // Limit shrink wrapping via the current iterative bit vector
- // implementation to functions with <= 500 MBBs.
- if (Fn.size() > 500) {
- DEBUG(if (ShrinkWrapThisFunction)
- DOUT << "DISABLED: " << Fn.getFunction()->getName()
- << ": too large (" << Fn.size() << " MBBs)\n");
- ShrinkWrapThisFunction = false;
- }
-
- // Return now if not shrink wrapping.
- if (! ShrinkWrapThisFunction)
- return false;
-
- // Collect set of used CSRs.
- for (unsigned inx = 0, e = CSI.size(); inx != e; ++inx) {
- UsedCSRegs.set(inx);
- }
-
- // Walk instructions in all MBBs, create CSRUsed[] sets, choose
- // whether or not to shrink wrap this function.
- MachineLoopInfo &LI = getAnalysis<MachineLoopInfo>();
- MachineDominatorTree &DT = getAnalysis<MachineDominatorTree>();
- const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
-
- bool allCSRUsesInEntryBlock = true;
- 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(Reg, MOReg))) {
- // CSR Reg is defined/used in block MBB.
- CSRUsed[MBB].set(inx);
- // Check for uses in EntryBlock.
- if (MBB != EntryBlock)
- allCSRUsesInEntryBlock = false;
- }
- }
- }
- }
-
- if (CSRUsed[MBB].empty())
- continue;
-
- // Propagate CSRUsed[MBB] in loops
- if (MachineLoop* LP = LI.getLoopFor(MBB)) {
- // Add top level loop to work list.
- MachineBasicBlock* HDR = getTopLevelLoopPreheader(LP);
- MachineLoop* PLP = getTopLevelLoopParent(LP);
-
- if (! HDR) {
- HDR = PLP->getHeader();
- assert(HDR->pred_size() > 0 && "Loop header has no predecessors?");
- MachineBasicBlock::pred_iterator PI = HDR->pred_begin();
- HDR = *PI;
- }
- TLLoops[HDR] = PLP;
-
- // Push uses from inside loop to its parent loops,
- // or to all other MBBs in its loop.
- if (LP->getLoopDepth() > 1) {
- for (MachineLoop* PLP = LP->getParentLoop(); PLP;
- PLP = PLP->getParentLoop()) {
- propagateUsesAroundLoop(MBB, PLP);
- }
- } else {
- propagateUsesAroundLoop(MBB, LP);
- }
- }
- }
-
- if (allCSRUsesInEntryBlock) {
- DEBUG(DOUT << "DISABLED: " << Fn.getFunction()->getName()
- << ": all CSRs used in EntryBlock\n");
- ShrinkWrapThisFunction = false;
- } else {
- bool allCSRsUsedInEntryFanout = true;
- for (MachineBasicBlock::succ_iterator SI = EntryBlock->succ_begin(),
- SE = EntryBlock->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock* SUCC = *SI;
- if (CSRUsed[SUCC] != UsedCSRegs)
- allCSRsUsedInEntryFanout = false;
- }
- if (allCSRsUsedInEntryFanout) {
- DEBUG(DOUT << "DISABLED: " << Fn.getFunction()->getName()
- << ": all CSRs used in imm successors of EntryBlock\n");
- ShrinkWrapThisFunction = false;
- }
- }
-
- if (ShrinkWrapThisFunction) {
- // Check if MBB uses CSRs and dominates all exit nodes.
- // Such nodes are equiv. to the entry node w.r.t.
- // CSR uses: every path through the function must
- // pass through this node. If each CSR is used at least
- // once by these nodes, shrink wrapping is disabled.
- CSRegSet CSRUsedInChokePoints;
- for (MachineFunction::iterator MBBI = Fn.begin(), MBBE = Fn.end();
- MBBI != MBBE; ++MBBI) {
- MachineBasicBlock* MBB = MBBI;
- if (MBB == EntryBlock || CSRUsed[MBB].empty() || MBB->succ_size() < 1)
- continue;
- bool dominatesExitNodes = true;
- for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri)
- if (! DT.dominates(MBB, ReturnBlocks[ri])) {
- dominatesExitNodes = false;
- break;
- }
- if (dominatesExitNodes) {
- CSRUsedInChokePoints |= CSRUsed[MBB];
- if (CSRUsedInChokePoints == UsedCSRegs) {
- DEBUG(DOUT << "DISABLED: " << Fn.getFunction()->getName()
- << ": all CSRs used in choke point(s) at "
- << getBasicBlockName(MBB) << "\n");
- ShrinkWrapThisFunction = false;
- break;
- }
- }
- }
- }
-
- // Return now if we have decided not to apply shrink wrapping
- // to the current function.
- if (! ShrinkWrapThisFunction)
- return false;
-
- DEBUG({
- DOUT << "ENABLED: " << Fn.getFunction()->getName();
- if (HasFastExitPath)
- DOUT << " (fast exit path)";
- DOUT << "\n";
- if (ShrinkWrapDebugging >= BasicInfo) {
- DOUT << "------------------------------"
- << "-----------------------------\n";
- DOUT << "UsedCSRegs = " << stringifyCSRegSet(UsedCSRegs) << "\n";
- if (ShrinkWrapDebugging >= Details) {
- DOUT << "------------------------------"
- << "-----------------------------\n";
- dumpAllUsed();
- }
- }
- });
-
- // Build initial DF sets to determine minimal regions in the
- // Machine CFG around which CSRs must be spilled and restored.
- calculateAnticAvail(Fn);
-
- return true;
-}
-
-/// addUsesForMEMERegion - add uses of CSRs spilled or restored in
-/// multi-entry, multi-exit (MEME) regions so spill and restore
-/// placement will not break code that enters or leaves a
-/// shrink-wrapped region by inducing spills with no matching
-/// restores or restores with no matching spills. A MEME region
-/// is a subgraph of the MCFG with multiple entry edges, multiple
-/// exit edges, or both. This code propagates use information
-/// through the MCFG until all paths requiring spills and restores
-/// _outside_ the computed minimal placement regions have been covered.
-///
-bool PEI::addUsesForMEMERegion(MachineBasicBlock* MBB,
- SmallVector<MachineBasicBlock*, 4>& blks) {
- if (MBB->succ_size() < 2 && MBB->pred_size() < 2) {
- bool processThisBlock = false;
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock* SUCC = *SI;
- if (SUCC->pred_size() > 1) {
- processThisBlock = true;
- break;
- }
- }
- if (!CSRRestore[MBB].empty() && MBB->succ_size() > 0) {
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- MachineBasicBlock* PRED = *PI;
- if (PRED->succ_size() > 1) {
- processThisBlock = true;
- break;
- }
- }
- }
- if (! processThisBlock)
- return false;
- }
-
- CSRegSet prop;
- if (!CSRSave[MBB].empty())
- prop = CSRSave[MBB];
- else if (!CSRRestore[MBB].empty())
- prop = CSRRestore[MBB];
- else
- prop = CSRUsed[MBB];
- if (prop.empty())
- return false;
-
- // Propagate selected bits to successors, predecessors of MBB.
- bool addedUses = false;
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock* SUCC = *SI;
- // Self-loop
- if (SUCC == MBB)
- continue;
- if (! CSRUsed[SUCC].contains(prop)) {
- CSRUsed[SUCC] |= prop;
- addedUses = true;
- blks.push_back(SUCC);
- DEBUG(if (ShrinkWrapDebugging >= Iterations)
- DOUT << getBasicBlockName(MBB)
- << "(" << stringifyCSRegSet(prop) << ")->"
- << "successor " << getBasicBlockName(SUCC) << "\n");
- }
- }
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- MachineBasicBlock* PRED = *PI;
- // Self-loop
- if (PRED == MBB)
- continue;
- if (! CSRUsed[PRED].contains(prop)) {
- CSRUsed[PRED] |= prop;
- addedUses = true;
- blks.push_back(PRED);
- DEBUG(if (ShrinkWrapDebugging >= Iterations)
- DOUT << getBasicBlockName(MBB)
- << "(" << stringifyCSRegSet(prop) << ")->"
- << "predecessor " << getBasicBlockName(PRED) << "\n");
- }
- }
- return addedUses;
-}
-
-/// addUsesForTopLevelLoops - add uses for CSRs used inside top
-/// level loops to the exit blocks of those loops.
-///
-bool PEI::addUsesForTopLevelLoops(SmallVector<MachineBasicBlock*, 4>& blks) {
- bool addedUses = false;
-
- // Place restores for top level loops where needed.
- for (DenseMap<MachineBasicBlock*, MachineLoop*>::iterator
- I = TLLoops.begin(), E = TLLoops.end(); I != E; ++I) {
- MachineBasicBlock* MBB = I->first;
- MachineLoop* LP = I->second;
- MachineBasicBlock* HDR = LP->getHeader();
- SmallVector<MachineBasicBlock*, 4> exitBlocks;
- CSRegSet loopSpills;
-
- loopSpills = CSRSave[MBB];
- if (CSRSave[MBB].empty()) {
- loopSpills = CSRUsed[HDR];
- assert(!loopSpills.empty() && "No CSRs used in loop?");
- } else if (CSRRestore[MBB].contains(CSRSave[MBB]))
- continue;
-
- 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];
- if (! CSRUsed[EXB].contains(loopSpills)) {
- CSRUsed[EXB] |= loopSpills;
- addedUses = true;
- DEBUG(if (ShrinkWrapDebugging >= Iterations)
- DOUT << "LOOP " << getBasicBlockName(MBB)
- << "(" << stringifyCSRegSet(loopSpills) << ")->"
- << getBasicBlockName(EXB) << "\n");
- if (EXB->succ_size() > 1 || EXB->pred_size() > 1)
- blks.push_back(EXB);
+ 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;
+ AdjustsStack = true;
+ FrameSDOps.push_back(I);
+ } else if (I->isInlineAsm()) {
+ // Some inline asm's need a stack frame, as indicated by operand 1.
+ unsigned ExtraInfo = I->getOperand(InlineAsm::MIOp_ExtraInfo).getImm();
+ if (ExtraInfo & InlineAsm::Extra_IsAlignStack)
+ AdjustsStack = true;
}
- }
- }
- return addedUses;
-}
-/// calcSpillPlacements - determine which CSRs should be spilled
-/// in MBB using AnticIn sets of MBB's predecessors, keeping track
-/// of changes to spilled reg sets. Add MBB to the set of blocks
-/// that need to be processed for propagating use info to cover
-/// multi-entry/exit regions.
-///
-bool PEI::calcSpillPlacements(MachineBasicBlock* MBB,
- SmallVector<MachineBasicBlock*, 4> &blks,
- CSRegBlockMap &prevSpills) {
- bool placedSpills = false;
- // Intersect (CSRegs - AnticIn[P]) for P in Predecessors(MBB)
- CSRegSet anticInPreds;
- SmallVector<MachineBasicBlock*, 4> predecessors;
- for (MachineBasicBlock::pred_iterator PI = MBB->pred_begin(),
- PE = MBB->pred_end(); PI != PE; ++PI) {
- MachineBasicBlock* PRED = *PI;
- if (PRED != MBB)
- predecessors.push_back(PRED);
- }
- unsigned i = 0, e = predecessors.size();
- if (i != e) {
- MachineBasicBlock* PRED = predecessors[i];
- anticInPreds = UsedCSRegs - AnticIn[PRED];
- for (++i; i != e; ++i) {
- PRED = predecessors[i];
- anticInPreds &= (UsedCSRegs - AnticIn[PRED]);
- }
- } else {
- // Handle uses in entry blocks (which have no predecessors).
- // This is necessary because the DFA formulation assumes the
- // entry and (multiple) exit nodes cannot have CSR uses, which
- // is not the case in the real world.
- anticInPreds = UsedCSRegs;
- }
- // Compute spills required at MBB:
- CSRSave[MBB] |= (AnticIn[MBB] - AvailIn[MBB]) & anticInPreds;
+ MFI->setAdjustsStack(AdjustsStack);
+ MFI->setMaxCallFrameSize(MaxCallFrameSize);
- if (! CSRSave[MBB].empty()) {
- if (MBB == EntryBlock) {
- for (unsigned ri = 0, re = ReturnBlocks.size(); ri != re; ++ri)
- CSRRestore[ReturnBlocks[ri]] |= CSRSave[MBB];
- } else {
- // Reset all regs spilled in MBB that are also spilled in EntryBlock.
- if (CSRSave[EntryBlock].intersects(CSRSave[MBB])) {
- CSRSave[MBB] = CSRSave[MBB] - CSRSave[EntryBlock];
- }
- }
- }
- placedSpills = (CSRSave[MBB] != prevSpills[MBB]);
- prevSpills[MBB] = CSRSave[MBB];
- // Remember this block for adding restores to successor
- // blocks for multi-entry region.
- if (placedSpills)
- blks.push_back(MBB);
-
- DEBUG(if (! CSRSave[MBB].empty() && ShrinkWrapDebugging >= Iterations)
- DOUT << "SAVE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(CSRSave[MBB]) << "\n");
-
- return placedSpills;
-}
+ for (std::vector<MachineBasicBlock::iterator>::iterator
+ i = FrameSDOps.begin(), e = FrameSDOps.end(); i != e; ++i) {
+ MachineBasicBlock::iterator I = *i;
-/// calcRestorePlacements - determine which CSRs should be restored
-/// in MBB using AvailOut sets of MBB's succcessors, keeping track
-/// of changes to restored reg sets. Add MBB to the set of blocks
-/// that need to be processed for propagating use info to cover
-/// multi-entry/exit regions.
-///
-bool PEI::calcRestorePlacements(MachineBasicBlock* MBB,
- SmallVector<MachineBasicBlock*, 4> &blks,
- CSRegBlockMap &prevRestores) {
- bool placedRestores = false;
- // Intersect (CSRegs - AvailOut[S]) for S in Successors(MBB)
- CSRegSet availOutSucc;
- SmallVector<MachineBasicBlock*, 4> successors;
- for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
- SE = MBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock* SUCC = *SI;
- if (SUCC != MBB)
- successors.push_back(SUCC);
- }
- unsigned i = 0, e = successors.size();
- if (i != e) {
- MachineBasicBlock* SUCC = successors[i];
- availOutSucc = UsedCSRegs - AvailOut[SUCC];
- for (++i; i != e; ++i) {
- SUCC = successors[i];
- availOutSucc &= (UsedCSRegs - AvailOut[SUCC]);
- }
- } else {
- if (! CSRUsed[MBB].empty() || ! AvailOut[MBB].empty()) {
- // Handle uses in return blocks (which have no successors).
- // This is necessary because the DFA formulation assumes the
- // entry and (multiple) exit nodes cannot have CSR uses, which
- // is not the case in the real world.
- availOutSucc = UsedCSRegs;
- }
- }
- // Compute restores required at MBB:
- CSRRestore[MBB] |= (AvailOut[MBB] - AnticOut[MBB]) & availOutSucc;
-
- // Postprocess restore placements at MBB.
- // 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 (MBB->succ_size() && ! CSRRestore[MBB].empty()) {
- if (! CSRSave[EntryBlock].empty())
- CSRRestore[MBB] = CSRRestore[MBB] - CSRSave[EntryBlock];
+ // 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 (TFI->canSimplifyCallFramePseudos(Fn))
+ RegInfo->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
}
- placedRestores = (CSRRestore[MBB] != prevRestores[MBB]);
- prevRestores[MBB] = CSRRestore[MBB];
- // Remember this block for adding saves to predecessor
- // blocks for multi-entry region.
- if (placedRestores)
- blks.push_back(MBB);
-
- DEBUG(if (! CSRRestore[MBB].empty() && ShrinkWrapDebugging >= Iterations)
- DOUT << "RESTORE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(CSRRestore[MBB]) << "\n");
-
- return placedRestores;
}
-/// placeSpillsAndRestores - place spills and restores of CSRs
-/// used in MBBs in minimal regions that contain the uses.
-///
-void PEI::placeSpillsAndRestores(MachineFunction &Fn) {
- CSRegBlockMap prevCSRSave;
- CSRegBlockMap prevCSRRestore;
- SmallVector<MachineBasicBlock*, 4> cvBlocks, ncvBlocks;
- bool changed = true;
- unsigned iterations = 0;
-
- // Iterate computation of spill and restore placements in the MCFG until:
- // 1. CSR use info has been fully propagated around the MCFG, and
- // 2. computation of CSRSave[], CSRRestore[] reach fixed points.
- while (changed) {
- changed = false;
- ++iterations;
-
- DEBUG(if (ShrinkWrapDebugging >= Iterations)
- DOUT << "iter " << iterations
- << " --------------------------------------------------\n");
-
- // Calculate CSR{Save,Restore} sets using Antic, Avail on the MCFG,
- // which determines the placements of spills and restores.
- // Keep track of changes to spills, restores in each iteration to
- // minimize the total iterations.
- bool SRChanged = false;
- for (MachineFunction::iterator MBBI = Fn.begin(), MBBE = Fn.end();
- MBBI != MBBE; ++MBBI) {
- MachineBasicBlock* MBB = MBBI;
-
- // Place spills for CSRs in MBB.
- SRChanged |= calcSpillPlacements(MBB, cvBlocks, prevCSRSave);
-
- // Place restores for CSRs in MBB.
- SRChanged |= calcRestorePlacements(MBB, cvBlocks, prevCSRRestore);
- }
-
- // Add uses of CSRs used inside loops where needed.
- changed |= addUsesForTopLevelLoops(cvBlocks);
-
- // Add uses for CSRs spilled or restored at branch, join points.
- if (changed || SRChanged) {
- while (! cvBlocks.empty()) {
- MachineBasicBlock* MBB = cvBlocks.pop_back_val();
- changed |= addUsesForMEMERegion(MBB, ncvBlocks);
- }
- if (! ncvBlocks.empty()) {
- cvBlocks = ncvBlocks;
- ncvBlocks.clear();
- }
- }
-
- if (changed) {
- calculateAnticAvail(Fn);
- CSRSave.clear();
- CSRRestore.clear();
- }
- }
-
- // Check for effectiveness:
- // SR0 = {r | r in CSRSave[EntryBlock], CSRRestore[RB], RB in ReturnBlocks}
- // numSRReduced = |(UsedCSRegs - SR0)|, approx. SR0 by CSRSave[EntryBlock]
- // Gives a measure of how many CSR spills have been moved from EntryBlock
- // to minimal regions enclosing their uses.
- CSRegSet notSpilledInEntryBlock = (UsedCSRegs - CSRSave[EntryBlock]);
- unsigned numSRReducedThisFunc = notSpilledInEntryBlock.count();
- numSRReduced += numSRReducedThisFunc;
- DEBUG(if (ShrinkWrapDebugging >= BasicInfo) {
- DOUT << "-----------------------------------------------------------\n";
- DOUT << "total iterations = " << iterations << " ( "
- << Fn.getFunction()->getName()
- << " " << numSRReducedThisFunc
- << " " << Fn.size()
- << " )\n";
- DOUT << "-----------------------------------------------------------\n";
- dumpSRSets();
- DOUT << "-----------------------------------------------------------\n";
- if (numSRReducedThisFunc)
- verifySpillRestorePlacement();
- });
-}
/// 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.
-///
+/// registers.
void PEI::calculateCalleeSavedRegisters(MachineFunction &Fn) {
const TargetRegisterInfo *RegInfo = Fn.getTarget().getRegisterInfo();
- const TargetFrameInfo *TFI = Fn.getTarget().getFrameInfo();
+ const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering();
+ MachineFrameInfo *MFI = Fn.getFrameInfo();
// Get the callee saved register list...
const unsigned *CSRegs = RegInfo->getCalleeSavedRegs(&Fn);
- // 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 callee saved registers.
+ if (CSRegs == 0 || CSRegs[0] == 0)
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 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))
- RegInfo->eliminateCallFramePseudoInstr(Fn, *I->getParent(), I);
- }
+ // In Naked functions we aren't going to save any registers.
+ if (Fn.getFunction()->hasFnAttr(Attribute::Naked))
+ return;
- // Now 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 =
- 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!
- CSI.push_back(CalleeSavedInfo(Reg, CSRegClasses[i]));
+ // If the reg is modified, save it!
+ CSI.push_back(CalleeSavedInfo(Reg));
} else {
for (const unsigned *AliasSet = RegInfo->getAliasSet(Reg);
*AliasSet; ++AliasSet) { // Check alias registers too.
if (Fn.getRegInfo().isPhysRegUsed(*AliasSet)) {
- CSI.push_back(CalleeSavedInfo(Reg, CSRegClasses[i]));
+ CSI.push_back(CalleeSavedInfo(Reg));
break;
}
}
return; // Early exit if no callee saved registers are modified!
unsigned NumFixedSpillSlots;
- const std::pair<unsigned,int> *FixedSpillSlots =
+ const TargetFrameLowering::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 = RegInfo->getMinimalPhysRegClass(Reg);
+
+ 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 TargetFrameLowering::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 = MFI->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 = MFI->CreateFixedObject(RC->getSize(), FixedSlot->Offset, true);
}
- CSI[i].setFrameIdx(FrameIdx);
+
+ I->setFrameIdx(FrameIdx);
}
- FFI->setCalleeSavedInfo(CSI);
+ MFI->setCalleeSavedInfo(CSI);
}
/// insertCSRSpillsAndRestores - Insert spill and restore code for
///
void PEI::insertCSRSpillsAndRestores(MachineFunction &Fn) {
// Get callee saved register information.
- MachineFrameInfo *FFI = Fn.getFrameInfo();
- const std::vector<CalleeSavedInfo> &CSI = FFI->getCalleeSavedInfo();
+ MachineFrameInfo *MFI = Fn.getFrameInfo();
+ const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
+
+ MFI->setCalleeSavedInfoValid(true);
// Early exit if no callee saved registers are modified!
if (CSI.empty())
return;
const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
+ const TargetFrameLowering *TFI = Fn.getTarget().getFrameLowering();
+ const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
MachineBasicBlock::iterator I;
- DEBUG(if (ShrinkWrapThisFunction && ShrinkWrapDebugging >= Details)
- DOUT << "Inserting CSR spills/restores in function "
- << Fn.getFunction()->getName() << "\n");
-
if (! ShrinkWrapThisFunction) {
// Spill using target interface.
I = EntryBlock->begin();
- if (!TII.spillCalleeSavedRegisters(*EntryBlock, I, CSI)) {
+ if (!TFI->spillCalleeSavedRegisters(*EntryBlock, I, CSI, TRI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
// Add the callee-saved register as live-in.
// It's killed at the spill.
EntryBlock->addLiveIn(CSI[i].getReg());
// Insert the spill to the stack frame.
- TII.storeRegToStackSlot(*EntryBlock, I, CSI[i].getReg(), true,
- CSI[i].getFrameIdx(), CSI[i].getRegClass());
+ unsigned Reg = CSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.storeRegToStackSlot(*EntryBlock, I, Reg, true,
+ CSI[i].getFrameIdx(), RC, TRI);
}
}
--BeforeI;
// Restore all registers immediately before the return and any
- // terminators that preceed it.
- if (!TII.restoreCalleeSavedRegisters(*MBB, I, CSI)) {
+ // terminators that precede it.
+ if (!TFI->restoreCalleeSavedRegisters(*MBB, I, CSI, TRI)) {
for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
- TII.loadRegFromStackSlot(*MBB, I, CSI[i].getReg(),
+ unsigned Reg = CSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.loadRegFromStackSlot(*MBB, I, Reg,
CSI[i].getFrameIdx(),
- CSI[i].getRegClass());
+ RC, TRI);
assert(I != MBB->begin() &&
"loadRegFromStackSlot didn't insert any code!");
// Insert in reverse order. loadRegFromStackSlot can insert
if (save.empty())
continue;
- DEBUG(if (ShrinkWrapDebugging >= Details)
- DOUT << "Spilling " << stringifyCSRegSet(save)
- << " in " << getBasicBlockName(MBB) << "\n");
-
blockCSI.clear();
for (CSRegSet::iterator RI = save.begin(),
RE = save.end(); RI != RE; ++RI) {
MBB->addLiveIn(blockCSI[i].getReg());
// Insert the spill to the stack frame.
- TII.storeRegToStackSlot(*MBB, I, blockCSI[i].getReg(),
+ unsigned Reg = blockCSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.storeRegToStackSlot(*MBB, I, Reg,
true,
blockCSI[i].getFrameIdx(),
- blockCSI[i].getRegClass());
+ RC, TRI);
}
}
- DEBUG(if (ShrinkWrapDebugging >= Details)
- DOUT << "------------------------------"
- << "-----------------------------\n");
-
for (CSRegBlockMap::iterator BI = CSRRestore.begin(),
BE = CSRRestore.end(); BI != BE; ++BI) {
MachineBasicBlock* MBB = BI->first;
if (restore.empty())
continue;
- DEBUG(if (ShrinkWrapDebugging >= Details)
- DOUT << "Restoring " << stringifyCSRegSet(restore)
- << " in " << getBasicBlockName(MBB) << "\n");
-
blockCSI.clear();
for (CSRegSet::iterator RI = restore.begin(),
RE = restore.end(); RI != RE; ++RI) {
--BeforeI;
// Restore all registers immediately before the return and any
- // terminators that preceed it.
+ // terminators that precede it.
for (unsigned i = 0, e = blockCSI.size(); i != e; ++i) {
- TII.loadRegFromStackSlot(*MBB, I, blockCSI[i].getReg(),
+ unsigned Reg = blockCSI[i].getReg();
+ const TargetRegisterClass *RC = TRI->getMinimalPhysRegClass(Reg);
+ TII.loadRegFromStackSlot(*MBB, I, Reg,
blockCSI[i].getFrameIdx(),
- blockCSI[i].getRegClass());
+ RC, TRI);
assert(I != MBB->begin() &&
"loadRegFromStackSlot didn't insert any code!");
// Insert in reverse order. loadRegFromStackSlot can insert
}
}
}
-
- DEBUG(if (ShrinkWrapDebugging >= Details)
- DOUT << "------------------------------"
- << "-----------------------------\n");
}
/// AdjustStackOffset - Helper function used to adjust the stack frame offset.
static inline void
-AdjustStackOffset(MachineFrameInfo *FFI, int FrameIdx,
+AdjustStackOffset(MachineFrameInfo *MFI, 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);
+ Offset += MFI->getObjectSize(FrameIdx);
- unsigned Align = FFI->getObjectAlignment(FrameIdx);
+ unsigned Align = MFI->getObjectAlignment(FrameIdx);
// If the alignment of this object is greater than that of the stack, then
// increase the stack alignment to match.
Offset = (Offset + Align - 1) / Align * Align;
if (StackGrowsDown) {
- FFI->setObjectOffset(FrameIdx, -Offset); // Set the computed offset
+ DEBUG(dbgs() << "alloc FI(" << FrameIdx << ") at SP[" << -Offset << "]\n");
+ MFI->setObjectOffset(FrameIdx, -Offset); // Set the computed offset
} else {
- FFI->setObjectOffset(FrameIdx, Offset);
- Offset += FFI->getObjectSize(FrameIdx);
+ DEBUG(dbgs() << "alloc FI(" << FrameIdx << ") at SP[" << Offset << "]\n");
+ MFI->setObjectOffset(FrameIdx, Offset);
+ Offset += MFI->getObjectSize(FrameIdx);
}
}
/// abstract stack objects.
///
void PEI::calculateFrameObjectOffsets(MachineFunction &Fn) {
- const TargetFrameInfo &TFI = *Fn.getTarget().getFrameInfo();
+ const TargetFrameLowering &TFI = *Fn.getTarget().getFrameLowering();
bool StackGrowsDown =
- TFI.getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
+ TFI.getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
// Loop over all of the stack objects, assigning sequential addresses...
- MachineFrameInfo *FFI = Fn.getFrameInfo();
-
- unsigned MaxAlign = FFI->getMaxAlignment();
+ MachineFrameInfo *MFI = Fn.getFrameInfo();
// 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.
// We currently don't support filling in holes in between fixed sized
// objects, so we adjust 'Offset' to point to the end of last fixed sized
// preallocated object.
- for (int i = FFI->getObjectIndexBegin(); i != 0; ++i) {
+ for (int i = MFI->getObjectIndexBegin(); i != 0; ++i) {
int64_t FixedOff;
if (StackGrowsDown) {
// The maximum distance from the stack pointer is at lower address of
// the object -- which is given by offset. For down growing stack
// the offset is negative, so we negate the offset to get the distance.
- FixedOff = -FFI->getObjectOffset(i);
+ FixedOff = -MFI->getObjectOffset(i);
} else {
// The maximum distance from the start pointer is at the upper
// address of the object.
- FixedOff = FFI->getObjectOffset(i) + FFI->getObjectSize(i);
+ FixedOff = MFI->getObjectOffset(i) + MFI->getObjectSize(i);
}
if (FixedOff > Offset) Offset = FixedOff;
}
// callee saved registers.
if (StackGrowsDown) {
for (unsigned i = MinCSFrameIndex; i <= MaxCSFrameIndex; ++i) {
- // If stack grows down, we need to add size of find the lowest
+ // If the stack grows down, we need to add the size to find the lowest
// address of the object.
- Offset += FFI->getObjectSize(i);
+ Offset += MFI->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);
+ unsigned Align = MFI->getObjectAlignment(i);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
- FFI->setObjectOffset(i, -Offset); // Set the computed offset
+ MFI->setObjectOffset(i, -Offset); // Set the computed offset
}
} else {
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);
+ unsigned Align = MFI->getObjectAlignment(i);
// Adjust to alignment boundary
Offset = (Offset+Align-1)/Align*Align;
- FFI->setObjectOffset(i, Offset);
- Offset += FFI->getObjectSize(i);
+ MFI->setObjectOffset(i, Offset);
+ Offset += MFI->getObjectSize(i);
}
}
+ unsigned MaxAlign = MFI->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 && TFI.hasFP(Fn) && RegInfo->useFPForScavengingIndex(Fn) &&
+ !RegInfo->needsStackRealignment(Fn)) {
int SFI = RS->getScavengingFrameIndex();
if (SFI >= 0)
- AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
+ AdjustStackOffset(MFI, SFI, StackGrowsDown, Offset, MaxAlign);
+ }
+
+ // FIXME: Once this is working, then enable flag will change to a target
+ // check for whether the frame is large enough to want to use virtual
+ // frame index registers. Functions which don't want/need this optimization
+ // will continue to use the existing code path.
+ if (MFI->getUseLocalStackAllocationBlock()) {
+ unsigned Align = MFI->getLocalFrameMaxAlign();
+
+ // Adjust to alignment boundary.
+ Offset = (Offset + Align - 1) / Align * Align;
+
+ DEBUG(dbgs() << "Local frame base offset: " << Offset << "\n");
+
+ // Resolve offsets for objects in the local block.
+ for (unsigned i = 0, e = MFI->getLocalFrameObjectCount(); i != e; ++i) {
+ std::pair<int, int64_t> Entry = MFI->getLocalFrameObjectMap(i);
+ int64_t FIOffset = (StackGrowsDown ? -Offset : Offset) + Entry.second;
+ DEBUG(dbgs() << "alloc FI(" << Entry.first << ") at SP[" <<
+ FIOffset << "]\n");
+ MFI->setObjectOffset(Entry.first, FIOffset);
+ }
+ // Allocate the local block
+ Offset += MFI->getLocalFrameSize();
+
+ MaxAlign = std::max(Align, MaxAlign);
}
// Make sure that the stack protector comes before the local variables on the
// stack.
- if (FFI->getStackProtectorIndex() >= 0)
- AdjustStackOffset(FFI, FFI->getStackProtectorIndex(), StackGrowsDown,
+ SmallSet<int, 16> LargeStackObjs;
+ if (MFI->getStackProtectorIndex() >= 0) {
+ AdjustStackOffset(MFI, MFI->getStackProtectorIndex(), StackGrowsDown,
Offset, MaxAlign);
+ // Assign large stack objects first.
+ for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
+ if (MFI->isObjectPreAllocated(i) &&
+ MFI->getUseLocalStackAllocationBlock())
+ continue;
+ if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
+ continue;
+ if (RS && (int)i == RS->getScavengingFrameIndex())
+ continue;
+ if (MFI->isDeadObjectIndex(i))
+ continue;
+ if (MFI->getStackProtectorIndex() == (int)i)
+ continue;
+ if (!MFI->MayNeedStackProtector(i))
+ continue;
+
+ AdjustStackOffset(MFI, i, StackGrowsDown, Offset, MaxAlign);
+ LargeStackObjs.insert(i);
+ }
+ }
+
// Then assign frame offsets to stack objects that are not used to spill
// callee saved registers.
- for (unsigned i = 0, e = FFI->getObjectIndexEnd(); i != e; ++i) {
+ for (unsigned i = 0, e = MFI->getObjectIndexEnd(); i != e; ++i) {
+ if (MFI->isObjectPreAllocated(i) &&
+ MFI->getUseLocalStackAllocationBlock())
+ continue;
if (i >= MinCSFrameIndex && i <= MaxCSFrameIndex)
continue;
if (RS && (int)i == RS->getScavengingFrameIndex())
continue;
- if (FFI->isDeadObjectIndex(i))
+ if (MFI->isDeadObjectIndex(i))
continue;
- if (FFI->getStackProtectorIndex() == (int)i)
+ if (MFI->getStackProtectorIndex() == (int)i)
+ continue;
+ if (LargeStackObjs.count(i))
continue;
- AdjustStackOffset(FFI, i, StackGrowsDown, Offset, MaxAlign);
+ AdjustStackOffset(MFI, i, StackGrowsDown, Offset, MaxAlign);
}
// Make sure the special register scavenging spill slot is closest to the
// stack pointer.
- if (RS && !RegInfo->hasFP(Fn)) {
+ if (RS && (!TFI.hasFP(Fn) || RegInfo->needsStackRealignment(Fn) ||
+ !RegInfo->useFPForScavengingIndex(Fn))) {
int SFI = RS->getScavengingFrameIndex();
if (SFI >= 0)
- AdjustStackOffset(FFI, SFI, StackGrowsDown, Offset, MaxAlign);
+ AdjustStackOffset(MFI, 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 (!TFI.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))
- Offset += FFI->getMaxCallFrameSize();
+ if (MFI->adjustsStack() && TFI.hasReservedCallFrame(Fn))
+ Offset += MFI->getMaxCallFrameSize();
+
+ // 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 (MFI->adjustsStack() || MFI->hasVarSizedObjects() ||
+ (RegInfo->needsStackRealignment(Fn) && MFI->getObjectIndexEnd() != 0))
+ StackAlign = TFI.getStackAlignment();
+ else
+ StackAlign = TFI.getTransientStackAlignment();
- unsigned AlignMask = std::max(TFI.getStackAlignment(),MaxAlign) - 1;
+ // 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);
+ int64_t StackSize = Offset - LocalAreaOffset;
+ MFI->setStackSize(StackSize);
+ NumBytesStackSpace += StackSize;
}
-
/// insertPrologEpilogCode - Scan the function for modified callee saved
/// registers, insert spill code for these callee saved registers, then add
/// prolog and epilog code to the function.
///
void PEI::insertPrologEpilogCode(MachineFunction &Fn) {
- const TargetRegisterInfo *TRI = Fn.getTarget().getRegisterInfo();
+ const TargetFrameLowering &TFI = *Fn.getTarget().getFrameLowering();
// Add prologue to the function...
- TRI->emitPrologue(Fn);
+ TFI.emitPrologue(Fn);
// Add epilogue to restore the callee-save registers in each exiting block
for (MachineFunction::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
// If last instruction is a return instruction, add an epilogue
if (!I->empty() && I->back().getDesc().isReturn())
- TRI->emitEpilogue(Fn, *I);
+ TFI.emitEpilogue(Fn, *I);
}
-}
+ // Emit additional code that is required to support segmented stacks, if
+ // we've been asked for it. This, when linked with a runtime with support
+ // for segmented stacks (libgcc is one), will result in allocating stack
+ // space in small chunks instead of one large contiguous block.
+ if (EnableSegmentedStacks)
+ TFI.adjustForSegmentedStacks(Fn);
+}
/// replaceFrameIndices - Replace all MO_FrameIndex operands with physical
/// register references and actual offsets.
const TargetMachine &TM = Fn.getTarget();
assert(TM.getRegisterInfo() && "TM::getRegisterInfo() must be implemented!");
+ const TargetInstrInfo &TII = *Fn.getTarget().getInstrInfo();
const TargetRegisterInfo &TRI = *TM.getRegisterInfo();
- const TargetFrameInfo *TFI = TM.getFrameInfo();
+ const TargetFrameLowering *TFI = TM.getFrameLowering();
bool StackGrowsDown =
- TFI->getStackGrowthDirection() == TargetFrameInfo::StackGrowsDown;
- int FrameSetupOpcode = TRI.getCallFrameSetupOpcode();
- int FrameDestroyOpcode = TRI.getCallFrameDestroyOpcode();
+ TFI->getStackGrowthDirection() == TargetFrameLowering::StackGrowsDown;
+ int FrameSetupOpcode = TII.getCallFrameSetupOpcode();
+ int FrameDestroyOpcode = TII.getCallFrameDestroyOpcode();
for (MachineFunction::iterator BB = Fn.begin(),
E = Fn.end(); BB != E; ++BB) {
+#ifndef NDEBUG
+ int SPAdjCount = 0; // frame setup / destroy count.
+#endif
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) {
+#ifndef NDEBUG
+ // Track whether we see even pairs of them
+ SPAdjCount += I->getOpcode() == FrameSetupOpcode ? 1 : -1;
+#endif
// Remember how much SP has been adjusted to create the call
// frame.
int Size = I->getOperand(0).getImm();
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);
+ TRI.eliminateFrameIndex(MI, SPAdj,
+ FrameIndexVirtualScavenging ? NULL : RS);
// 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?");
+ // If we have evenly matched pairs of frame setup / destroy instructions,
+ // make sure the adjustments come out to zero. If we don't have matched
+ // pairs, we can't be sure the missing bit isn't in another basic block
+ // due to a custom inserter playing tricks, so just asserting SPAdj==0
+ // isn't sufficient. See tMOVCC on Thumb1, for example.
+ assert((SPAdjCount || SPAdj == 0) &&
+ "Unbalanced call frame setup / destroy pairs?");
}
}
-// Debugging methods for shrink wrapping.
-#ifndef NDEBUG
-/// findFastExitPath - debugging method used to detect functions
-/// with at least one path from the entry block to a return block
-/// directly or which has a very small number of edges.
-///
-void PEI::findFastExitPath() {
- if (! EntryBlock)
- return;
- // Fina a path from EntryBlock to any return block that does not branch:
- // Entry
- // | ...
- // v |
- // B1<-----+
- // |
- // v
- // Return
- for (MachineBasicBlock::succ_iterator SI = EntryBlock->succ_begin(),
- SE = EntryBlock->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock* SUCC = *SI;
-
- // Assume positive, disprove existence of fast path.
-#ifndef NDEBUG
- HasFastExitPath = true;
-#endif
-
- // Check the immediate successors.
- if (isReturnBlock(SUCC)) {
- if (ShrinkWrapDebugging >= BasicInfo)
- DOUT << "Fast exit path: " << getBasicBlockName(EntryBlock)
- << "->" << getBasicBlockName(SUCC) << "\n";
- break;
- }
- // Traverse df from SUCC, look for a branch block.
- std::string exitPath = getBasicBlockName(SUCC);
- for (df_iterator<MachineBasicBlock*> BI = df_begin(SUCC),
- BE = df_end(SUCC); BI != BE; ++BI) {
- MachineBasicBlock* SBB = *BI;
- // Reject paths with branch nodes.
- if (SBB->succ_size() > 1) {
-#ifndef NDEBUG
- HasFastExitPath = false;
-#endif
- break;
- }
- exitPath += "->" + getBasicBlockName(SBB);
- }
-#ifndef NDEBUG
- if (HasFastExitPath) {
-#endif
- if (ShrinkWrapDebugging >= BasicInfo)
- DOUT << "Fast exit path: " << getBasicBlockName(EntryBlock)
- << "->" << exitPath << "\n";
- break;
-#ifndef NDEBUG
- }
-#endif
- }
-}
-
-/// verifySpillRestorePlacement - check the current spill/restore
-/// sets for safety. Attempt to find spills without restores or
-/// restores without spills.
-/// Spills: walk df from each MBB in spill set ensuring that
-/// all CSRs spilled at MMBB are restored on all paths
-/// from MBB to all exit blocks.
-/// Restores: walk idf from each MBB in restore set ensuring that
-/// all CSRs restored at MBB are spilled on all paths
-/// reaching MBB.
-///
-void PEI::verifySpillRestorePlacement() {
- unsigned numReturnBlocks = 0;
- for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end();
- MBBI != MBBE; ++MBBI) {
- MachineBasicBlock* MBB = MBBI;
- if (isReturnBlock(MBB) || MBB->succ_size() == 0)
- ++numReturnBlocks;
- }
- for (CSRegBlockMap::iterator BI = CSRSave.begin(),
- BE = CSRSave.end(); BI != BE; ++BI) {
- MachineBasicBlock* MBB = BI->first;
- CSRegSet spilled = BI->second;
- CSRegSet restored;
+/// 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);
- if (spilled.empty())
- continue;
+ unsigned VirtReg = 0;
+ unsigned ScratchReg = 0;
+ int SPAdj = 0;
- DOUT << "SAVE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(spilled)
- << " RESTORE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(CSRRestore[MBB]) << "\n";
+ // 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;
+ 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))
+ continue;
- if (CSRRestore[MBB].intersects(spilled)) {
- restored |= (CSRRestore[MBB] & spilled);
- }
+ ++NumVirtualFrameRegs;
+
+ // Have we already allocated a scratch register for this virtual?
+ if (Reg != VirtReg) {
+ // When we first encounter a new virtual register, it
+ // must be a definition.
+ assert(MI->getOperand(i).isDef() &&
+ "frame index virtual missing def!");
+ // Scavenge a new scratch register
+ VirtReg = Reg;
+ const TargetRegisterClass *RC = Fn.getRegInfo().getRegClass(Reg);
+ ScratchReg = RS->scavengeRegister(RC, I, SPAdj);
+ ++NumScavengedRegs;
+ }
+ // Replace this reference to the virtual register with the
+ // scratch register.
+ assert (ScratchReg && "Missing scratch register!");
+ MI->getOperand(i).setReg(ScratchReg);
- // Walk depth first from MBB to find restores of all CSRs spilled at MBB:
- // we must find restores for all spills w/no intervening spills on all
- // paths from MBB to all return blocks.
- for (df_iterator<MachineBasicBlock*> BI = df_begin(MBB),
- BE = df_end(MBB); BI != BE; ++BI) {
- MachineBasicBlock* SBB = *BI;
- if (SBB == MBB)
- continue;
- // Stop when we encounter spills of any CSRs spilled at MBB that
- // have not yet been seen to be restored.
- if (CSRSave[SBB].intersects(spilled) &&
- !restored.contains(CSRSave[SBB] & spilled))
- break;
- // Collect the CSRs spilled at MBB that are restored
- // at this DF successor of MBB.
- if (CSRRestore[SBB].intersects(spilled))
- restored |= (CSRRestore[SBB] & spilled);
- // If we are at a retun block, check that the restores
- // we have seen so far exhaust the spills at MBB, then
- // reset the restores.
- if (isReturnBlock(SBB) || SBB->succ_size() == 0) {
- if (restored != spilled) {
- CSRegSet notRestored = (spilled - restored);
- DOUT << MF->getFunction()->getName() << ": "
- << stringifyCSRegSet(notRestored)
- << " spilled at " << getBasicBlockName(MBB)
- << " are never restored on path to return "
- << getBasicBlockName(SBB) << "\n";
}
- restored.clear();
}
+ RS->forward(I);
+ ++I;
}
}
-
- // Check restore placements.
- for (CSRegBlockMap::iterator BI = CSRRestore.begin(),
- BE = CSRRestore.end(); BI != BE; ++BI) {
- MachineBasicBlock* MBB = BI->first;
- CSRegSet restored = BI->second;
- CSRegSet spilled;
-
- if (restored.empty())
- continue;
-
- DOUT << "SAVE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(CSRSave[MBB])
- << " RESTORE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(restored) << "\n";
-
- if (CSRSave[MBB].intersects(restored)) {
- spilled |= (CSRSave[MBB] & restored);
- }
- // Walk inverse depth first from MBB to find spills of all
- // CSRs restored at MBB:
- for (idf_iterator<MachineBasicBlock*> BI = idf_begin(MBB),
- BE = idf_end(MBB); BI != BE; ++BI) {
- MachineBasicBlock* PBB = *BI;
- if (PBB == MBB)
- continue;
- // Stop when we encounter restores of any CSRs restored at MBB that
- // have not yet been seen to be spilled.
- if (CSRRestore[PBB].intersects(restored) &&
- !spilled.contains(CSRRestore[PBB] & restored))
- break;
- // Collect the CSRs restored at MBB that are spilled
- // at this DF predecessor of MBB.
- if (CSRSave[PBB].intersects(restored))
- spilled |= (CSRSave[PBB] & restored);
- }
- if (spilled != restored) {
- CSRegSet notSpilled = (restored - spilled);
- DOUT << MF->getFunction()->getName() << ": "
- << stringifyCSRegSet(notSpilled)
- << " restored at " << getBasicBlockName(MBB)
- << " are never spilled\n";
- }
- }
-}
-
-// Debugging print methods.
-std::string PEI::getBasicBlockName(const MachineBasicBlock* MBB) {
- std::ostringstream name;
- if (MBB) {
- if (MBB->getBasicBlock())
- name << MBB->getBasicBlock()->getName();
- else
- name << "_MBB_" << MBB->getNumber();
- }
- return name.str();
-}
-
-std::string PEI::stringifyCSRegSet(const CSRegSet& s) {
- const TargetRegisterInfo* TRI = MF->getTarget().getRegisterInfo();
- const std::vector<CalleeSavedInfo> CSI =
- MF->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();
-}
-
-void PEI::dumpSet(const CSRegSet& s) {
- DOUT << stringifyCSRegSet(s) << "\n";
}
-
-void PEI::dumpUsed(MachineBasicBlock* MBB) {
- if (MBB) {
- DOUT << "CSRUsed[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(CSRUsed[MBB]) << "\n";
- }
-}
-
-void PEI::dumpAllUsed() {
- for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end();
- MBBI != MBBE; ++MBBI) {
- MachineBasicBlock* MBB = MBBI;
- dumpUsed(MBB);
- }
-}
-
-void PEI::dumpSets(MachineBasicBlock* MBB) {
- if (MBB) {
- DOUT << getBasicBlockName(MBB) << " | "
- << stringifyCSRegSet(CSRUsed[MBB]) << " | "
- << stringifyCSRegSet(AnticIn[MBB]) << " | "
- << stringifyCSRegSet(AnticOut[MBB]) << " | "
- << stringifyCSRegSet(AvailIn[MBB]) << " | "
- << stringifyCSRegSet(AvailOut[MBB]) << "\n";
- }
-}
-
-void PEI::dumpSets1(MachineBasicBlock* MBB) {
- if (MBB) {
- DOUT << getBasicBlockName(MBB) << " | "
- << stringifyCSRegSet(CSRUsed[MBB]) << " | "
- << stringifyCSRegSet(AnticIn[MBB]) << " | "
- << stringifyCSRegSet(AnticOut[MBB]) << " | "
- << stringifyCSRegSet(AvailIn[MBB]) << " | "
- << stringifyCSRegSet(AvailOut[MBB]) << " | "
- << stringifyCSRegSet(CSRSave[MBB]) << " | "
- << stringifyCSRegSet(CSRRestore[MBB]) << "\n";
- }
-}
-
-void PEI::dumpAllSets() {
- for (MachineFunction::iterator MBBI = MF->begin(), MBBE = MF->end();
- MBBI != MBBE; ++MBBI) {
- MachineBasicBlock* MBB = MBBI;
- dumpSets1(MBB);
- }
-}
-
-void PEI::dumpSRSets() {
- for (MachineFunction::iterator MBB = MF->begin(), E = MF->end();
- MBB != E; ++MBB) {
- if (! CSRSave[MBB].empty()) {
- DOUT << "SAVE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(CSRSave[MBB]);
- if (CSRRestore[MBB].empty())
- DOUT << "\n";
- }
- if (! CSRRestore[MBB].empty()) {
- if (! CSRSave[MBB].empty())
- DOUT << " ";
- DOUT << "RESTORE[" << getBasicBlockName(MBB) << "] = "
- << stringifyCSRegSet(CSRRestore[MBB]) << "\n";
- }
- }
-}
-#endif
projects / oota-llvm.git / blobdiff