//
//===----------------------------------------------------------------------===//
-#define DEBUG_TYPE "stackcoloring"
-#include "MachineTraceMetrics.h"
-#include "llvm/Function.h"
-#include "llvm/Module.h"
+#include "llvm/CodeGen/Passes.h"
#include "llvm/ADT/BitVector.h"
-#include "llvm/Analysis/Dominators.h"
-#include "llvm/Analysis/ValueTracking.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SparseSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/CodeGen/LiveInterval.h"
-#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
-#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/MachineMemOperand.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
-#include "llvm/CodeGen/MachineFrameInfo.h"
-#include "llvm/CodeGen/MachineMemOperand.h"
-#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/PseudoSourceValue.h"
#include "llvm/CodeGen/SlotIndexes.h"
-#include "llvm/DebugInfo.h"
-#include "llvm/MC/MCInstrItineraries.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/CodeGen/StackProtector.h"
+#include "llvm/CodeGen/WinEHFuncInfo.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
using namespace llvm;
+#define DEBUG_TYPE "stackcoloring"
+
static cl::opt<bool>
DisableColoring("no-stack-coloring",
- cl::init(true), cl::Hidden,
- cl::desc("Suppress stack coloring"));
+ cl::init(false), cl::Hidden,
+ cl::desc("Disable stack coloring"));
+
+/// The user may write code that uses allocas outside of the declared lifetime
+/// zone. This can happen when the user returns a reference to a local
+/// data-structure. We can detect these cases and decide not to optimize the
+/// code. If this flag is enabled, we try to save the user.
+static cl::opt<bool>
+ProtectFromEscapedAllocas("protect-from-escaped-allocas",
+ cl::init(false), cl::Hidden,
+ cl::desc("Do not optimize lifetime zones that "
+ "are broken"));
-STATISTIC(NumMarkerSeen, "Number of life markers found.");
+STATISTIC(NumMarkerSeen, "Number of lifetime markers found.");
STATISTIC(StackSpaceSaved, "Number of bytes saved due to merging slots.");
STATISTIC(StackSlotMerged, "Number of stack slot merged.");
+STATISTIC(EscapedAllocas, "Number of allocas that escaped the lifetime region");
//===----------------------------------------------------------------------===//
// StackColoring Pass
};
/// Maps active slots (per bit) for each basic block.
- DenseMap<MachineBasicBlock*, BlockLifetimeInfo> BlockLiveness;
+ typedef DenseMap<const MachineBasicBlock*, BlockLifetimeInfo> LivenessMap;
+ LivenessMap BlockLiveness;
/// Maps serial numbers to basic blocks.
- DenseMap<MachineBasicBlock*, int> BasicBlocks;
+ DenseMap<const MachineBasicBlock*, int> BasicBlocks;
/// Maps basic blocks to a serial number.
- SmallVector<MachineBasicBlock*, 8> BasicBlockNumbering;
+ SmallVector<const MachineBasicBlock*, 8> BasicBlockNumbering;
/// Maps liveness intervals for each slot.
- SmallVector<LiveInterval*, 16> Intervals;
+ SmallVector<std::unique_ptr<LiveInterval>, 16> Intervals;
/// VNInfo is used for the construction of LiveIntervals.
VNInfo::Allocator VNInfoAllocator;
/// SlotIndex analysis object.
- SlotIndexes* Indexes;
+ SlotIndexes *Indexes;
+ /// The stack protector object.
+ StackProtector *SP;
/// The list of lifetime markers found. These markers are to be removed
/// once the coloring is done.
SmallVector<MachineInstr*, 8> Markers;
- /// SlotSizeSorter - A Sort utility for arranging stack slots according
- /// to their size.
- struct SlotSizeSorter {
- MachineFrameInfo *MFI;
- SlotSizeSorter(MachineFrameInfo *mfi) : MFI(mfi) { }
- bool operator()(int LHS, int RHS) {
- // We use -1 to denote a uninteresting slot. Place these slots at the end.
- if (LHS == -1) return false;
- if (RHS == -1) return true;
- // Sort according to size.
- return MFI->getObjectSize(LHS) > MFI->getObjectSize(RHS);
- }
-};
-
public:
static char ID;
StackColoring() : MachineFunctionPass(ID) {
initializeStackColoringPass(*PassRegistry::getPassRegistry());
}
- void getAnalysisUsage(AnalysisUsage &AU) const;
- bool runOnMachineFunction(MachineFunction &MF);
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
+ bool runOnMachineFunction(MachineFunction &MF) override;
private:
/// Debug.
- void dump();
+ void dump() const;
/// Removes all of the lifetime marker instructions from the function.
/// \returns true if any markers were removed.
/// slots to use the joint slots.
void remapInstructions(DenseMap<int, int> &SlotRemap);
+ /// The input program may contain instructions which are not inside lifetime
+ /// markers. This can happen due to a bug in the compiler or due to a bug in
+ /// user code (for example, returning a reference to a local variable).
+ /// This procedure checks all of the instructions in the function and
+ /// invalidates lifetime ranges which do not contain all of the instructions
+ /// which access that frame slot.
+ void removeInvalidSlotRanges();
+
/// Map entries which point to other entries to their destination.
/// A->B->C becomes A->C.
void expungeSlotMap(DenseMap<int, int> &SlotRemap, unsigned NumSlots);
"stack-coloring", "Merge disjoint stack slots", false, false)
INITIALIZE_PASS_DEPENDENCY(MachineDominatorTree)
INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
+INITIALIZE_PASS_DEPENDENCY(StackProtector)
INITIALIZE_PASS_END(StackColoring,
"stack-coloring", "Merge disjoint stack slots", false, false)
AU.addRequired<MachineDominatorTree>();
AU.addPreserved<MachineDominatorTree>();
AU.addRequired<SlotIndexes>();
+ AU.addRequired<StackProtector>();
MachineFunctionPass::getAnalysisUsage(AU);
}
-void StackColoring::dump() {
- for (df_iterator<MachineFunction*> FI = df_begin(MF), FE = df_end(MF);
- FI != FE; ++FI) {
- unsigned Num = BasicBlocks[*FI];
- DEBUG(dbgs()<<"Inspecting block #"<<Num<<" ["<<FI->getName()<<"]\n");
- Num = 0;
+void StackColoring::dump() const {
+ for (MachineBasicBlock *MBB : depth_first(MF)) {
+ DEBUG(dbgs() << "Inspecting block #" << BasicBlocks.lookup(MBB) << " ["
+ << MBB->getName() << "]\n");
+
+ LivenessMap::const_iterator BI = BlockLiveness.find(MBB);
+ assert(BI != BlockLiveness.end() && "Block not found");
+ const BlockLifetimeInfo &BlockInfo = BI->second;
+
DEBUG(dbgs()<<"BEGIN : {");
- for (unsigned i=0; i < BlockLiveness[*FI].Begin.size(); ++i)
- DEBUG(dbgs()<<BlockLiveness[*FI].Begin.test(i)<<" ");
+ for (unsigned i=0; i < BlockInfo.Begin.size(); ++i)
+ DEBUG(dbgs()<<BlockInfo.Begin.test(i)<<" ");
DEBUG(dbgs()<<"}\n");
DEBUG(dbgs()<<"END : {");
- for (unsigned i=0; i < BlockLiveness[*FI].End.size(); ++i)
- DEBUG(dbgs()<<BlockLiveness[*FI].End.test(i)<<" ");
+ for (unsigned i=0; i < BlockInfo.End.size(); ++i)
+ DEBUG(dbgs()<<BlockInfo.End.test(i)<<" ");
DEBUG(dbgs()<<"}\n");
DEBUG(dbgs()<<"LIVE_IN: {");
- for (unsigned i=0; i < BlockLiveness[*FI].LiveIn.size(); ++i)
- DEBUG(dbgs()<<BlockLiveness[*FI].LiveIn.test(i)<<" ");
+ for (unsigned i=0; i < BlockInfo.LiveIn.size(); ++i)
+ DEBUG(dbgs()<<BlockInfo.LiveIn.test(i)<<" ");
DEBUG(dbgs()<<"}\n");
DEBUG(dbgs()<<"LIVEOUT: {");
- for (unsigned i=0; i < BlockLiveness[*FI].LiveOut.size(); ++i)
- DEBUG(dbgs()<<BlockLiveness[*FI].LiveOut.test(i)<<" ");
+ for (unsigned i=0; i < BlockInfo.LiveOut.size(); ++i)
+ DEBUG(dbgs()<<BlockInfo.LiveOut.test(i)<<" ");
DEBUG(dbgs()<<"}\n");
}
}
unsigned StackColoring::collectMarkers(unsigned NumSlot) {
unsigned MarkersFound = 0;
// Scan the function to find all lifetime markers.
- // NOTE: We use the a reverse-post-order iteration to ensure that we obtain a
+ // NOTE: We use a reverse-post-order iteration to ensure that we obtain a
// deterministic numbering, and because we'll need a post-order iteration
// later for solving the liveness dataflow problem.
- for (df_iterator<MachineFunction*> FI = df_begin(MF), FE = df_end(MF);
- FI != FE; ++FI) {
+ for (MachineBasicBlock *MBB : depth_first(MF)) {
// Assign a serial number to this basic block.
- BasicBlocks[*FI] = BasicBlockNumbering.size();;
- BasicBlockNumbering.push_back(*FI);
+ BasicBlocks[MBB] = BasicBlockNumbering.size();
+ BasicBlockNumbering.push_back(MBB);
- BlockLiveness[*FI].Begin.resize(NumSlot);
- BlockLiveness[*FI].End.resize(NumSlot);
+ // Keep a reference to avoid repeated lookups.
+ BlockLifetimeInfo &BlockInfo = BlockLiveness[MBB];
- for (MachineBasicBlock::iterator BI = (*FI)->begin(), BE = (*FI)->end();
- BI != BE; ++BI) {
+ BlockInfo.Begin.resize(NumSlot);
+ BlockInfo.End.resize(NumSlot);
- if (BI->getOpcode() != TargetOpcode::LIFETIME_START &&
- BI->getOpcode() != TargetOpcode::LIFETIME_END)
+ for (MachineInstr &MI : *MBB) {
+ if (MI.getOpcode() != TargetOpcode::LIFETIME_START &&
+ MI.getOpcode() != TargetOpcode::LIFETIME_END)
continue;
- Markers.push_back(BI);
+ Markers.push_back(&MI);
- bool IsStart = BI->getOpcode() == TargetOpcode::LIFETIME_START;
- MachineOperand &MI = BI->getOperand(0);
- unsigned Slot = MI.getIndex();
+ bool IsStart = MI.getOpcode() == TargetOpcode::LIFETIME_START;
+ const MachineOperand &MO = MI.getOperand(0);
+ unsigned Slot = MO.getIndex();
MarkersFound++;
- const Value* Allocation = MFI->getObjectAllocation(Slot);
+ const AllocaInst *Allocation = MFI->getObjectAllocation(Slot);
if (Allocation) {
- DEBUG(dbgs()<<"Found lifetime marker for allocation: "<<
- Allocation->getName()<<"\n");
+ DEBUG(dbgs()<<"Found a lifetime marker for slot #"<<Slot<<
+ " with allocation: "<< Allocation->getName()<<"\n");
}
if (IsStart) {
- BlockLiveness[*FI].Begin.set(Slot);
+ BlockInfo.Begin.set(Slot);
} else {
- if (BlockLiveness[*FI].Begin.test(Slot)) {
+ if (BlockInfo.Begin.test(Slot)) {
// Allocas that start and end within a single block are handled
// specially when computing the LiveIntervals to avoid pessimizing
// the liveness propagation.
- BlockLiveness[*FI].Begin.reset(Slot);
+ BlockInfo.Begin.reset(Slot);
} else {
- BlockLiveness[*FI].End.set(Slot);
+ BlockInfo.End.set(Slot);
}
}
}
// formulation, and END is equivalent to GEN. The result of this computation
// is a map from blocks to bitvectors where the bitvectors represent which
// allocas are live in/out of that block.
- SmallPtrSet<MachineBasicBlock*, 8> BBSet(BasicBlockNumbering.begin(),
- BasicBlockNumbering.end());
+ SmallPtrSet<const MachineBasicBlock*, 8> BBSet(BasicBlockNumbering.begin(),
+ BasicBlockNumbering.end());
unsigned NumSSMIters = 0;
bool changed = true;
while (changed) {
changed = false;
++NumSSMIters;
- SmallPtrSet<MachineBasicBlock*, 8> NextBBSet;
-
- for (SmallVector<MachineBasicBlock*, 8>::iterator
- PI = BasicBlockNumbering.begin(), PE = BasicBlockNumbering.end();
- PI != PE; ++PI) {
+ SmallPtrSet<const MachineBasicBlock*, 8> NextBBSet;
- MachineBasicBlock *BB = *PI;
+ for (const MachineBasicBlock *BB : BasicBlockNumbering) {
if (!BBSet.count(BB)) continue;
+ // Use an iterator to avoid repeated lookups.
+ LivenessMap::iterator BI = BlockLiveness.find(BB);
+ assert(BI != BlockLiveness.end() && "Block not found");
+ BlockLifetimeInfo &BlockInfo = BI->second;
+
BitVector LocalLiveIn;
BitVector LocalLiveOut;
// Forward propagation from begins to ends.
- for (MachineBasicBlock::pred_iterator PI = BB->pred_begin(),
- PE = BB->pred_end(); PI != PE; ++PI)
- LocalLiveIn |= BlockLiveness[*PI].LiveOut;
- LocalLiveIn |= BlockLiveness[BB].End;
- LocalLiveIn.reset(BlockLiveness[BB].Begin);
+ for (MachineBasicBlock::const_pred_iterator PI = BB->pred_begin(),
+ PE = BB->pred_end(); PI != PE; ++PI) {
+ LivenessMap::const_iterator I = BlockLiveness.find(*PI);
+ assert(I != BlockLiveness.end() && "Predecessor not found");
+ LocalLiveIn |= I->second.LiveOut;
+ }
+ LocalLiveIn |= BlockInfo.End;
+ LocalLiveIn.reset(BlockInfo.Begin);
// Reverse propagation from ends to begins.
- for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(),
- SE = BB->succ_end(); SI != SE; ++SI)
- LocalLiveOut |= BlockLiveness[*SI].LiveIn;
- LocalLiveOut |= BlockLiveness[BB].Begin;
- LocalLiveOut.reset(BlockLiveness[BB].End);
+ for (MachineBasicBlock::const_succ_iterator SI = BB->succ_begin(),
+ SE = BB->succ_end(); SI != SE; ++SI) {
+ LivenessMap::const_iterator I = BlockLiveness.find(*SI);
+ assert(I != BlockLiveness.end() && "Successor not found");
+ LocalLiveOut |= I->second.LiveIn;
+ }
+ LocalLiveOut |= BlockInfo.Begin;
+ LocalLiveOut.reset(BlockInfo.End);
LocalLiveIn |= LocalLiveOut;
LocalLiveOut |= LocalLiveIn;
// After adopting the live bits, we need to turn-off the bits which
// are de-activated in this block.
- LocalLiveOut.reset(BlockLiveness[BB].End);
- LocalLiveIn.reset(BlockLiveness[BB].Begin);
-
- if (LocalLiveIn.test(BlockLiveness[BB].LiveIn)) {
+ LocalLiveOut.reset(BlockInfo.End);
+ LocalLiveIn.reset(BlockInfo.Begin);
+
+ // If we have both BEGIN and END markers in the same basic block then
+ // we know that the BEGIN marker comes after the END, because we already
+ // handle the case where the BEGIN comes before the END when collecting
+ // the markers (and building the BEGIN/END vectore).
+ // Want to enable the LIVE_IN and LIVE_OUT of slots that have both
+ // BEGIN and END because it means that the value lives before and after
+ // this basic block.
+ BitVector LocalEndBegin = BlockInfo.End;
+ LocalEndBegin &= BlockInfo.Begin;
+ LocalLiveIn |= LocalEndBegin;
+ LocalLiveOut |= LocalEndBegin;
+
+ if (LocalLiveIn.test(BlockInfo.LiveIn)) {
changed = true;
- BlockLiveness[BB].LiveIn |= LocalLiveIn;
+ BlockInfo.LiveIn |= LocalLiveIn;
- for (MachineBasicBlock::pred_iterator PI = BB->pred_begin(),
- PE = BB->pred_end(); PI != PE; ++PI)
- NextBBSet.insert(*PI);
+ NextBBSet.insert(BB->pred_begin(), BB->pred_end());
}
- if (LocalLiveOut.test(BlockLiveness[BB].LiveOut)) {
+ if (LocalLiveOut.test(BlockInfo.LiveOut)) {
changed = true;
- BlockLiveness[BB].LiveOut |= LocalLiveOut;
+ BlockInfo.LiveOut |= LocalLiveOut;
- for (MachineBasicBlock::succ_iterator SI = BB->succ_begin(),
- SE = BB->succ_end(); SI != SE; ++SI)
- NextBBSet.insert(*SI);
+ NextBBSet.insert(BB->succ_begin(), BB->succ_end());
}
}
- BBSet = NextBBSet;
+ BBSet = std::move(NextBBSet);
}// while changed.
}
// For each block, find which slots are active within this block
// and update the live intervals.
- for (MachineFunction::iterator MBB = MF->begin(), MBBe = MF->end();
- MBB != MBBe; ++MBB) {
+ for (const MachineBasicBlock &MBB : *MF) {
Starts.clear();
Starts.resize(NumSlots);
Finishes.clear();
Finishes.resize(NumSlots);
- BitVector Alive = BlockLiveness[MBB].LiveIn;
- Alive |= BlockLiveness[MBB].LiveOut;
-
- if (Alive.any()) {
- for (int pos = Alive.find_first(); pos != -1;
- pos = Alive.find_next(pos)) {
- Starts[pos] = Indexes->getMBBStartIdx(MBB);
- Finishes[pos] = Indexes->getMBBEndIdx(MBB);
- }
- }
+ // Create the interval for the basic blocks with lifetime markers in them.
+ for (const MachineInstr *MI : Markers) {
+ if (MI->getParent() != &MBB)
+ continue;
- for (SmallVector<MachineInstr*, 8>::iterator it = Markers.begin(),
- e = Markers.end(); it != e; ++it) {
- MachineInstr *MI = *it;
assert((MI->getOpcode() == TargetOpcode::LIFETIME_START ||
MI->getOpcode() == TargetOpcode::LIFETIME_END) &&
"Invalid Lifetime marker");
- if (MI->getParent() == MBB) {
- bool IsStart = MI->getOpcode() == TargetOpcode::LIFETIME_START;
- MachineOperand &Mo = MI->getOperand(0);
- int Slot = Mo.getIndex();
- assert(Slot >= 0 && "Invalid slot");
- if (IsStart) {
- Starts[Slot] = Indexes->getInstructionIndex(MI);
- } else {
- Finishes[Slot] = Indexes->getInstructionIndex(MI);
- }
+ bool IsStart = MI->getOpcode() == TargetOpcode::LIFETIME_START;
+ const MachineOperand &Mo = MI->getOperand(0);
+ int Slot = Mo.getIndex();
+ assert(Slot >= 0 && "Invalid slot");
+
+ SlotIndex ThisIndex = Indexes->getInstructionIndex(MI);
+
+ if (IsStart) {
+ if (!Starts[Slot].isValid() || Starts[Slot] > ThisIndex)
+ Starts[Slot] = ThisIndex;
+ } else {
+ if (!Finishes[Slot].isValid() || Finishes[Slot] < ThisIndex)
+ Finishes[Slot] = ThisIndex;
}
}
+ // Create the interval of the blocks that we previously found to be 'alive'.
+ BlockLifetimeInfo &MBBLiveness = BlockLiveness[&MBB];
+ for (int pos = MBBLiveness.LiveIn.find_first(); pos != -1;
+ pos = MBBLiveness.LiveIn.find_next(pos)) {
+ Starts[pos] = Indexes->getMBBStartIdx(&MBB);
+ }
+ for (int pos = MBBLiveness.LiveOut.find_first(); pos != -1;
+ pos = MBBLiveness.LiveOut.find_next(pos)) {
+ Finishes[pos] = Indexes->getMBBEndIdx(&MBB);
+ }
+
for (unsigned i = 0; i < NumSlots; ++i) {
- assert(!!Starts[i] == !!Finishes[i] && "Unmatched range");
- if (Starts[i] == Finishes[i])
+ assert(Starts[i].isValid() == Finishes[i].isValid() && "Unmatched range");
+ if (!Starts[i].isValid())
continue;
assert(Starts[i] && Finishes[i] && "Invalid interval");
SlotIndex F = Finishes[i];
if (S < F) {
// We have a single consecutive region.
- Intervals[i]->addRange(LiveRange(S, F, ValNum));
+ Intervals[i]->addSegment(LiveInterval::Segment(S, F, ValNum));
} else {
- // We have two non consecutive regions. This happens when
+ // We have two non-consecutive regions. This happens when
// LIFETIME_START appears after the LIFETIME_END marker.
- SlotIndex NewStart = Indexes->getMBBStartIdx(MBB);
- SlotIndex NewFin = Indexes->getMBBEndIdx(MBB);
- Intervals[i]->addRange(LiveRange(NewStart, F, ValNum));
- Intervals[i]->addRange(LiveRange(S, NewFin, ValNum));
+ SlotIndex NewStart = Indexes->getMBBStartIdx(&MBB);
+ SlotIndex NewFin = Indexes->getMBBEndIdx(&MBB);
+ Intervals[i]->addSegment(LiveInterval::Segment(NewStart, F, ValNum));
+ Intervals[i]->addSegment(LiveInterval::Segment(S, NewFin, ValNum));
}
}
}
bool StackColoring::removeAllMarkers() {
unsigned Count = 0;
- for (unsigned i = 0; i < Markers.size(); ++i) {
- Markers[i]->eraseFromParent();
+ for (MachineInstr *MI : Markers) {
+ MI->eraseFromParent();
Count++;
}
Markers.clear();
MachineModuleInfo *MMI = &MF->getMMI();
// Remap debug information that refers to stack slots.
- MachineModuleInfo::VariableDbgInfoMapTy &VMap = MMI->getVariableDbgInfo();
- for (MachineModuleInfo::VariableDbgInfoMapTy::iterator VI = VMap.begin(),
- VE = VMap.end(); VI != VE; ++VI) {
- const MDNode *Var = VI->first;
- if (!Var) continue;
- std::pair<unsigned, DebugLoc> &VP = VI->second;
- if (SlotRemap.count(VP.first)) {
- DEBUG(dbgs()<<"Remapping debug info for ["<<Var->getName()<<"].\n");
- VP.first = SlotRemap[VP.first];
+ for (auto &VI : MMI->getVariableDbgInfo()) {
+ if (!VI.Var)
+ continue;
+ if (SlotRemap.count(VI.Slot)) {
+ DEBUG(dbgs() << "Remapping debug info for ["
+ << cast<DILocalVariable>(VI.Var)->getName() << "].\n");
+ VI.Slot = SlotRemap[VI.Slot];
FixedDbg++;
}
}
// Keep a list of *allocas* which need to be remapped.
- DenseMap<const Value*, const Value*> Allocas;
- for (DenseMap<int, int>::iterator it = SlotRemap.begin(),
- e = SlotRemap.end(); it != e; ++it) {
- const Value* From = MFI->getObjectAllocation(it->first);
- const Value* To = MFI->getObjectAllocation(it->second);
+ DenseMap<const AllocaInst*, const AllocaInst*> Allocas;
+ for (const std::pair<int, int> &SI : SlotRemap) {
+ const AllocaInst *From = MFI->getObjectAllocation(SI.first);
+ const AllocaInst *To = MFI->getObjectAllocation(SI.second);
assert(To && From && "Invalid allocation object");
Allocas[From] = To;
+
+ // AA might be used later for instruction scheduling, and we need it to be
+ // able to deduce the correct aliasing releationships between pointers
+ // derived from the alloca being remapped and the target of that remapping.
+ // The only safe way, without directly informing AA about the remapping
+ // somehow, is to directly update the IR to reflect the change being made
+ // here.
+ Instruction *Inst = const_cast<AllocaInst *>(To);
+ if (From->getType() != To->getType()) {
+ BitCastInst *Cast = new BitCastInst(Inst, From->getType());
+ Cast->insertAfter(Inst);
+ Inst = Cast;
+ }
+
+ // Allow the stack protector to adjust its value map to account for the
+ // upcoming replacement.
+ SP->adjustForColoring(From, To);
+
+ // Note that this will not replace uses in MMOs (which we'll update below),
+ // or anywhere else (which is why we won't delete the original
+ // instruction).
+ const_cast<AllocaInst *>(From)->replaceAllUsesWith(Inst);
}
// Remap all instructions to the new stack slots.
- MachineFunction::iterator BB, BBE;
- MachineBasicBlock::iterator I, IE;
- for (BB = MF->begin(), BBE = MF->end(); BB != BBE; ++BB)
- for (I = BB->begin(), IE = BB->end(); I != IE; ++I) {
+ for (MachineBasicBlock &BB : *MF)
+ for (MachineInstr &I : BB) {
+ // Skip lifetime markers. We'll remove them soon.
+ if (I.getOpcode() == TargetOpcode::LIFETIME_START ||
+ I.getOpcode() == TargetOpcode::LIFETIME_END)
+ continue;
// Update the MachineMemOperand to use the new alloca.
- for (MachineInstr::mmo_iterator MM = I->memoperands_begin(),
- E = I->memoperands_end(); MM != E; ++MM) {
- MachineMemOperand *MMO = *MM;
-
- const Value *V = MMO->getValue();
-
- if (!V)
+ for (MachineMemOperand *MMO : I.memoperands()) {
+ // FIXME: In order to enable the use of TBAA when using AA in CodeGen,
+ // we'll also need to update the TBAA nodes in MMOs with values
+ // derived from the merged allocas. When doing this, we'll need to use
+ // the same variant of GetUnderlyingObjects that is used by the
+ // instruction scheduler (that can look through ptrtoint/inttoptr
+ // pairs).
+
+ // We've replaced IR-level uses of the remapped allocas, so we only
+ // need to replace direct uses here.
+ const AllocaInst *AI = dyn_cast_or_null<AllocaInst>(MMO->getValue());
+ if (!AI)
continue;
- // Climb up and find the original alloca.
- V = GetUnderlyingObject(V);
- // If we did not find one, or if the one that we found is not in our
- // map, then move on.
- if (!V || !Allocas.count(V))
+ if (!Allocas.count(AI))
continue;
- MMO->setValue(Allocas[V]);
+ MMO->setValue(Allocas[AI]);
FixedMemOp++;
}
// Update all of the machine instruction operands.
- for (unsigned i = 0 ; i < I->getNumOperands(); ++i) {
- MachineOperand &MO = I->getOperand(i);
-
+ for (MachineOperand &MO : I.operands()) {
if (!MO.isFI())
continue;
int FromSlot = MO.getIndex();
if (!SlotRemap.count(FromSlot))
continue;
+ // In a debug build, check that the instruction that we are modifying is
+ // inside the expected live range. If the instruction is not inside
+ // the calculated range then it means that the alloca usage moved
+ // outside of the lifetime markers, or that the user has a bug.
+ // NOTE: Alloca address calculations which happen outside the lifetime
+ // zone are are okay, despite the fact that we don't have a good way
+ // for validating all of the usages of the calculation.
+#ifndef NDEBUG
+ bool TouchesMemory = I.mayLoad() || I.mayStore();
+ // If we *don't* protect the user from escaped allocas, don't bother
+ // validating the instructions.
+ if (!I.isDebugValue() && TouchesMemory && ProtectFromEscapedAllocas) {
+ SlotIndex Index = Indexes->getInstructionIndex(&I);
+ const LiveInterval *Interval = &*Intervals[FromSlot];
+ assert(Interval->find(Index) != Interval->end() &&
+ "Found instruction usage outside of live range.");
+ }
+#endif
+
// Fix the machine instructions.
int ToSlot = SlotRemap[FromSlot];
MO.setIndex(ToSlot);
}
}
+ // Update the location of C++ catch objects for the MSVC personality routine.
+ if (WinEHFuncInfo *EHInfo = MF->getWinEHFuncInfo())
+ for (WinEHTryBlockMapEntry &TBME : EHInfo->TryBlockMap)
+ for (WinEHHandlerType &H : TBME.HandlerArray)
+ if (H.CatchObj.FrameIndex != INT_MAX &&
+ SlotRemap.count(H.CatchObj.FrameIndex))
+ H.CatchObj.FrameIndex = SlotRemap[H.CatchObj.FrameIndex];
+
DEBUG(dbgs()<<"Fixed "<<FixedMemOp<<" machine memory operands.\n");
DEBUG(dbgs()<<"Fixed "<<FixedDbg<<" debug locations.\n");
DEBUG(dbgs()<<"Fixed "<<FixedInstr<<" machine instructions.\n");
}
+void StackColoring::removeInvalidSlotRanges() {
+ for (MachineBasicBlock &BB : *MF)
+ for (MachineInstr &I : BB) {
+ if (I.getOpcode() == TargetOpcode::LIFETIME_START ||
+ I.getOpcode() == TargetOpcode::LIFETIME_END || I.isDebugValue())
+ continue;
+
+ // Some intervals are suspicious! In some cases we find address
+ // calculations outside of the lifetime zone, but not actual memory
+ // read or write. Memory accesses outside of the lifetime zone are a clear
+ // violation, but address calculations are okay. This can happen when
+ // GEPs are hoisted outside of the lifetime zone.
+ // So, in here we only check instructions which can read or write memory.
+ if (!I.mayLoad() && !I.mayStore())
+ continue;
+
+ // Check all of the machine operands.
+ for (const MachineOperand &MO : I.operands()) {
+ if (!MO.isFI())
+ continue;
+
+ int Slot = MO.getIndex();
+
+ if (Slot<0)
+ continue;
+
+ if (Intervals[Slot]->empty())
+ continue;
+
+ // Check that the used slot is inside the calculated lifetime range.
+ // If it is not, warn about it and invalidate the range.
+ LiveInterval *Interval = &*Intervals[Slot];
+ SlotIndex Index = Indexes->getInstructionIndex(&I);
+ if (Interval->find(Index) == Interval->end()) {
+ Interval->clear();
+ DEBUG(dbgs()<<"Invalidating range #"<<Slot<<"\n");
+ EscapedAllocas++;
+ }
+ }
+ }
+}
+
void StackColoring::expungeSlotMap(DenseMap<int, int> &SlotRemap,
unsigned NumSlots) {
// Expunge slot remap map.
}
bool StackColoring::runOnMachineFunction(MachineFunction &Func) {
+ if (skipOptnoneFunction(*Func.getFunction()))
+ return false;
+
DEBUG(dbgs() << "********** Stack Coloring **********\n"
<< "********** Function: "
- << ((Value*)Func.getFunction())->getName() << '\n');
+ << ((const Value*)Func.getFunction())->getName() << '\n');
MF = &Func;
MFI = MF->getFrameInfo();
Indexes = &getAnalysis<SlotIndexes>();
+ SP = &getAnalysis<StackProtector>();
BlockLiveness.clear();
BasicBlocks.clear();
BasicBlockNumbering.clear();
DEBUG(dbgs()<<"Total Stack size: "<<TotalSize<<" bytes\n\n");
// Don't continue because there are not enough lifetime markers, or the
- // stack or too small, or we are told not to optimize the slots.
+ // stack is too small, or we are told not to optimize the slots.
if (NumMarkers < 2 || TotalSize < 16 || DisableColoring) {
DEBUG(dbgs()<<"Will not try to merge slots.\n");
return removeAllMarkers();
}
for (unsigned i=0; i < NumSlots; ++i) {
- LiveInterval *LI = new LiveInterval(i, 0);
- Intervals.push_back(LI);
+ std::unique_ptr<LiveInterval> LI(new LiveInterval(i, 0));
LI->getNextValue(Indexes->getZeroIndex(), VNInfoAllocator);
+ Intervals.push_back(std::move(LI));
SortedSlots.push_back(i);
}
// Propagate the liveness information.
calculateLiveIntervals(NumSlots);
+ // Search for allocas which are used outside of the declared lifetime
+ // markers.
+ if (ProtectFromEscapedAllocas)
+ removeInvalidSlotRanges();
+
// Maps old slots to new slots.
DenseMap<int, int> SlotRemap;
unsigned RemovedSlots = 0;
// and continue.
// Sort the slots according to their size. Place unused slots at the end.
- std::sort(SortedSlots.begin(), SortedSlots.end(), SlotSizeSorter(MFI));
-
- bool Chanded = true;
- while (Chanded) {
- Chanded = false;
+ // Use stable sort to guarantee deterministic code generation.
+ std::stable_sort(SortedSlots.begin(), SortedSlots.end(),
+ [this](int LHS, int RHS) {
+ // We use -1 to denote a uninteresting slot. Place these slots at the end.
+ if (LHS == -1) return false;
+ if (RHS == -1) return true;
+ // Sort according to size.
+ return MFI->getObjectSize(LHS) > MFI->getObjectSize(RHS);
+ });
+
+ bool Changed = true;
+ while (Changed) {
+ Changed = false;
for (unsigned I = 0; I < NumSlots; ++I) {
if (SortedSlots[I] == -1)
continue;
- for (unsigned J=0; J < NumSlots; ++J) {
+ for (unsigned J=I+1; J < NumSlots; ++J) {
if (SortedSlots[J] == -1)
continue;
int FirstSlot = SortedSlots[I];
int SecondSlot = SortedSlots[J];
- LiveInterval *First = Intervals[FirstSlot];
- LiveInterval *Second = Intervals[SecondSlot];
+ LiveInterval *First = &*Intervals[FirstSlot];
+ LiveInterval *Second = &*Intervals[SecondSlot];
assert (!First->empty() && !Second->empty() && "Found an empty range");
// Merge disjoint slots.
if (!First->overlaps(*Second)) {
- Chanded = true;
- First->MergeRangesInAsValue(*Second, First->getValNumInfo(0));
+ Changed = true;
+ First->MergeSegmentsInAsValue(*Second, First->getValNumInfo(0));
SlotRemap[SecondSlot] = FirstSlot;
SortedSlots[J] = -1;
- DEBUG(dbgs()<<"Merging #"<<I<<" and slots #"<<J<<" together.\n");
+ DEBUG(dbgs()<<"Merging #"<<FirstSlot<<" and slots #"<<
+ SecondSlot<<" together.\n");
unsigned MaxAlignment = std::max(MFI->getObjectAlignment(FirstSlot),
MFI->getObjectAlignment(SecondSlot));
expungeSlotMap(SlotRemap, NumSlots);
remapInstructions(SlotRemap);
- // Release the intervals.
- for (unsigned I = 0; I < NumSlots; ++I) {
- delete Intervals[I];
- }
-
return removeAllMarkers();
}
projects / oota-llvm.git / blobdiff