cl::location(ClobberNonLive),
cl::Hidden);
+static cl::opt<bool> UseDeoptBundles("rs4gc-use-deopt-bundles", cl::Hidden,
+ cl::init(false));
+static cl::opt<bool>
+ AllowStatepointWithNoDeoptInfo("rs4gc-allow-statepoint-with-no-deopt-info",
+ cl::Hidden, cl::init(true));
+
namespace {
struct RewriteStatepointsForGC : public ModulePass {
static char ID; // Pass identification, replacement for typeid
Changed |= runOnFunction(F);
if (Changed) {
- // stripDereferenceabilityInfo asserts that shouldRewriteStatepointsIn
+ // stripNonValidAttributes asserts that shouldRewriteStatepointsIn
// returns true for at least one function in the module. Since at least
// one function changed, we know that the precondition is satisfied.
- stripDereferenceabilityInfo(M);
+ stripNonValidAttributes(M);
}
return Changed;
/// dereferenceability that are no longer valid/correct after
/// RewriteStatepointsForGC has run. This is because semantically, after
/// RewriteStatepointsForGC runs, all calls to gc.statepoint "free" the entire
- /// heap. stripDereferenceabilityInfo (conservatively) restores correctness
+ /// heap. stripNonValidAttributes (conservatively) restores correctness
/// by erasing all attributes in the module that externally imply
/// dereferenceability.
- ///
- void stripDereferenceabilityInfo(Module &M);
+ /// Similar reasoning also applies to the noalias attributes. gc.statepoint
+ /// can touch the entire heap including noalias objects.
+ void stripNonValidAttributes(Module &M);
- // Helpers for stripDereferenceabilityInfo
- void stripDereferenceabilityInfoFromBody(Function &F);
- void stripDereferenceabilityInfoFromPrototype(Function &F);
+ // Helpers for stripNonValidAttributes
+ void stripNonValidAttributesFromBody(Function &F);
+ void stripNonValidAttributesFromPrototype(Function &F);
};
} // namespace
// base relation will remain. Internally, we add a mixture of the two
// types, then update all the second type to the first type
typedef DenseMap<Value *, Value *> DefiningValueMapTy;
-typedef DenseSet<llvm::Value *> StatepointLiveSetTy;
-typedef DenseMap<Instruction *, Value *> RematerializedValueMapTy;
+typedef DenseSet<Value *> StatepointLiveSetTy;
+typedef DenseMap<AssertingVH<Instruction>, AssertingVH<Value>>
+ RematerializedValueMapTy;
struct PartiallyConstructedSafepointRecord {
/// The set of values known to be live across this safepoint
- StatepointLiveSetTy liveset;
+ StatepointLiveSetTy LiveSet;
/// Mapping from live pointers to a base-defining-value
- DenseMap<llvm::Value *, llvm::Value *> PointerToBase;
+ DenseMap<Value *, Value *> PointerToBase;
/// The *new* gc.statepoint instruction itself. This produces the token
/// that normal path gc.relocates and the gc.result are tied to.
Instruction *UnwindToken;
/// Record live values we are rematerialized instead of relocating.
- /// They are not included into 'liveset' field.
+ /// They are not included into 'LiveSet' field.
/// Maps rematerialized copy to it's original value.
RematerializedValueMapTy RematerializedValues;
};
}
+static ArrayRef<Use> GetDeoptBundleOperands(ImmutableCallSite CS) {
+ assert(UseDeoptBundles && "Should not be called otherwise!");
+
+ Optional<OperandBundleUse> DeoptBundle = CS.getOperandBundle("deopt");
+
+ if (!DeoptBundle.hasValue()) {
+ assert(AllowStatepointWithNoDeoptInfo &&
+ "Found non-leaf call without deopt info!");
+ return None;
+ }
+
+ return DeoptBundle.getValue().Inputs;
+}
+
/// Compute the live-in set for every basic block in the function
static void computeLiveInValues(DominatorTree &DT, Function &F,
GCPtrLivenessData &Data);
StatepointLiveSetTy &out);
// TODO: Once we can get to the GCStrategy, this becomes
-// Optional<bool> isGCManagedPointer(const Value *V) const override {
+// Optional<bool> isGCManagedPointer(const Type *Ty) const override {
static bool isGCPointerType(Type *T) {
if (auto *PT = dyn_cast<PointerType>(T))
if (ArrayType *AT = dyn_cast<ArrayType>(Ty))
return containsGCPtrType(AT->getElementType());
if (StructType *ST = dyn_cast<StructType>(Ty))
- return std::any_of(
- ST->subtypes().begin(), ST->subtypes().end(),
- [](Type *SubType) { return containsGCPtrType(SubType); });
+ return std::any_of(ST->subtypes().begin(), ST->subtypes().end(),
+ containsGCPtrType);
return false;
}
}
#endif
-static bool order_by_name(llvm::Value *a, llvm::Value *b) {
+static bool order_by_name(Value *a, Value *b) {
if (a->hasName() && b->hasName()) {
return -1 == a->getName().compare(b->getName());
} else if (a->hasName() && !b->hasName()) {
const CallSite &CS, PartiallyConstructedSafepointRecord &result) {
Instruction *inst = CS.getInstruction();
- StatepointLiveSetTy liveset;
- findLiveSetAtInst(inst, OriginalLivenessData, liveset);
+ StatepointLiveSetTy LiveSet;
+ findLiveSetAtInst(inst, OriginalLivenessData, LiveSet);
if (PrintLiveSet) {
// Note: This output is used by several of the test cases
// The order of elements in a set is not stable, put them in a vec and sort
// by name
SmallVector<Value *, 64> Temp;
- Temp.insert(Temp.end(), liveset.begin(), liveset.end());
+ Temp.insert(Temp.end(), LiveSet.begin(), LiveSet.end());
std::sort(Temp.begin(), Temp.end(), order_by_name);
errs() << "Live Variables:\n";
for (Value *V : Temp)
}
if (PrintLiveSetSize) {
errs() << "Safepoint For: " << CS.getCalledValue()->getName() << "\n";
- errs() << "Number live values: " << liveset.size() << "\n";
+ errs() << "Number live values: " << LiveSet.size() << "\n";
}
- result.liveset = liveset;
+ result.LiveSet = LiveSet;
}
static bool isKnownBaseResult(Value *V);
if (isa<Constant>(I)) {
assert(!isa<GlobalVariable>(I) && !isa<UndefValue>(I) &&
"order of checks wrong!");
- // Note: Finding a constant base for something marked for relocation
- // doesn't really make sense. The most likely case is either a) some
- // screwed up the address space usage or b) your validating against
- // compiled C++ code w/o the proper separation. The only real exception
- // is a null pointer. You could have generic code written to index of
- // off a potentially null value and have proven it null. We also use
- // null pointers in dead paths of relocation phis (which we might later
- // want to find a base pointer for).
- assert(isa<ConstantPointerNull>(I) &&
- "null is the only case which makes sense");
+ // Note: Even for frontends which don't have constant references, we can
+ // see constants appearing after optimizations. A simple example is
+ // specialization of an address computation on null feeding into a merge
+ // point where the actual use of the now-constant input is protected by
+ // another null check. (e.g. test4 in constants.ll)
return BaseDefiningValueResult(I, true);
}
if (CastInst *CI = dyn_cast<CastInst>(I)) {
Value *Def = CI->stripPointerCasts();
+ // If stripping pointer casts changes the address space there is an
+ // addrspacecast in between.
+ assert(cast<PointerType>(Def->getType())->getAddressSpace() ==
+ cast<PointerType>(CI->getType())->getAddressSpace() &&
+ "unsupported addrspacecast");
// If we find a cast instruction here, it means we've found a cast which is
// not simply a pointer cast (i.e. an inttoptr). We don't know how to
// handle int->ptr conversion.
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
switch (II->getIntrinsicID()) {
- case Intrinsic::experimental_gc_result_ptr:
default:
// fall through to general call handling
break;
case Intrinsic::experimental_gc_statepoint:
- case Intrinsic::experimental_gc_result_float:
- case Intrinsic::experimental_gc_result_int:
- llvm_unreachable("these don't produce pointers");
+ llvm_unreachable("statepoints don't produce pointers");
case Intrinsic::experimental_gc_relocate: {
// Rerunning safepoint insertion after safepoints are already
// inserted is not supported. It could probably be made to work,
private:
Status status;
- Value *base; // non null only if status == base
+ AssertingVH<Value> base; // non null only if status == base
};
}
bool progress = true;
while (progress) {
#ifndef NDEBUG
- size_t oldSize = States.size();
+ const size_t oldSize = States.size();
#endif
progress = false;
// We're only changing values in this loop, thus safe to keep iterators.
}
}
- assert(oldSize <= States.size());
- assert(oldSize == States.size() || progress);
+ assert(oldSize == States.size() &&
+ "fixed point shouldn't be adding any new nodes to state");
}
#ifndef NDEBUG
// instructions.
for (auto Pair : States) {
Instruction *BDV = cast<Instruction>(Pair.first);
- BDVState state = Pair.second;
+ BDVState State = Pair.second;
assert(!isKnownBaseResult(BDV) && "why did it get added?");
- assert(!state.isUnknown() && "Optimistic algorithm didn't complete!");
- if (!state.isConflict())
+ assert(!State.isUnknown() && "Optimistic algorithm didn't complete!");
+ if (!State.isConflict())
continue;
- if (PHINode *basephi = dyn_cast<PHINode>(state.getBase())) {
+ if (PHINode *basephi = dyn_cast<PHINode>(State.getBase())) {
PHINode *phi = cast<PHINode>(BDV);
unsigned NumPHIValues = phi->getNumIncomingValues();
for (unsigned i = 0; i < NumPHIValues; i++) {
basephi->addIncoming(Base, InBB);
}
assert(basephi->getNumIncomingValues() == NumPHIValues);
- } else if (SelectInst *BaseSel = dyn_cast<SelectInst>(state.getBase())) {
+ } else if (SelectInst *BaseSel = dyn_cast<SelectInst>(State.getBase())) {
SelectInst *Sel = cast<SelectInst>(BDV);
// Operand 1 & 2 are true, false path respectively. TODO: refactor to
// something more safe and less hacky.
Value *Base = getBaseForInput(InVal, BaseSel);
BaseSel->setOperand(i, Base);
}
- } else if (auto *BaseEE = dyn_cast<ExtractElementInst>(state.getBase())) {
+ } else if (auto *BaseEE = dyn_cast<ExtractElementInst>(State.getBase())) {
Value *InVal = cast<ExtractElementInst>(BDV)->getVectorOperand();
// Find the instruction which produces the base for each input. We may
// need to insert a bitcast.
Value *Base = getBaseForInput(InVal, BaseEE);
BaseEE->setOperand(0, Base);
} else {
- auto *BaseIE = cast<InsertElementInst>(state.getBase());
+ auto *BaseIE = cast<InsertElementInst>(State.getBase());
auto *BdvIE = cast<InsertElementInst>(BDV);
auto UpdateOperand = [&](int OperandIdx) {
Value *InVal = BdvIE->getOperand(OperandIdx);
- Value *Base = findBaseOrBDV(InVal, cache);
- if (!isKnownBaseResult(Base)) {
- // Either conflict or base.
- assert(States.count(Base));
- Base = States[Base].getBase();
- assert(Base != nullptr && "unknown BDVState!");
- }
- assert(Base && "can't be null");
+ Value *Base = getBaseForInput(InVal, BaseIE);
BaseIE->setOperand(OperandIdx, Base);
};
UpdateOperand(0); // vector operand
NewInsts.erase(BaseI);
ReverseMap.erase(BaseI);
BaseI->replaceAllUsesWith(Replacement);
- BaseI->eraseFromParent();
assert(States.count(BDV));
assert(States[BDV].isConflict() && States[BDV].getBase() == BaseI);
States[BDV] = BDVState(BDVState::Conflict, Replacement);
+ BaseI->eraseFromParent();
};
const DataLayout &DL = cast<Instruction>(def)->getModule()->getDataLayout();
while (!Worklist.empty()) {
}
cache[BDV] = base;
}
- assert(cache.find(def) != cache.end());
+ assert(cache.count(def));
return cache[def];
}
// pointer was a base pointer.
static void
findBasePointers(const StatepointLiveSetTy &live,
- DenseMap<llvm::Value *, llvm::Value *> &PointerToBase,
+ DenseMap<Value *, Value *> &PointerToBase,
DominatorTree *DT, DefiningValueMapTy &DVCache) {
// For the naming of values inserted to be deterministic - which makes for
// much cleaner and more stable tests - we need to assign an order to the
static void findBasePointers(DominatorTree &DT, DefiningValueMapTy &DVCache,
const CallSite &CS,
PartiallyConstructedSafepointRecord &result) {
- DenseMap<llvm::Value *, llvm::Value *> PointerToBase;
- findBasePointers(result.liveset, PointerToBase, &DT, DVCache);
+ DenseMap<Value *, Value *> PointerToBase;
+ findBasePointers(result.LiveSet, PointerToBase, &DT, DVCache);
if (PrintBasePointers) {
// Note: Need to print these in a stable order since this is checked in
std::sort(Temp.begin(), Temp.end(), order_by_name);
for (Value *Ptr : Temp) {
Value *Base = PointerToBase[Ptr];
- errs() << " derived %" << Ptr->getName() << " base %" << Base->getName()
- << "\n";
+ errs() << " derived ";
+ Ptr->printAsOperand(errs(), false);
+ errs() << " base ";
+ Base->printAsOperand(errs(), false);
+ errs() << "\n";;
}
}
PartiallyConstructedSafepointRecord &result);
static void recomputeLiveInValues(
- Function &F, DominatorTree &DT, Pass *P, ArrayRef<CallSite> toUpdate,
+ Function &F, DominatorTree &DT, ArrayRef<CallSite> toUpdate,
MutableArrayRef<struct PartiallyConstructedSafepointRecord> records) {
// TODO-PERF: reuse the original liveness, then simply run the dataflow
// again. The old values are still live and will help it stabilize quickly.
}
}
-// When inserting gc.relocate calls, we need to ensure there are no uses
-// of the original value between the gc.statepoint and the gc.relocate call.
-// One case which can arise is a phi node starting one of the successor blocks.
-// We also need to be able to insert the gc.relocates only on the path which
-// goes through the statepoint. We might need to split an edge to make this
-// possible.
+// When inserting gc.relocate and gc.result calls, we need to ensure there are
+// no uses of the original value / return value between the gc.statepoint and
+// the gc.relocate / gc.result call. One case which can arise is a phi node
+// starting one of the successor blocks. We also need to be able to insert the
+// gc.relocates only on the path which goes through the statepoint. We might
+// need to split an edge to make this possible.
static BasicBlock *
normalizeForInvokeSafepoint(BasicBlock *BB, BasicBlock *InvokeParent,
DominatorTree &DT) {
BasicBlock *Ret = BB;
- if (!BB->getUniquePredecessor()) {
+ if (!BB->getUniquePredecessor())
Ret = SplitBlockPredecessors(BB, InvokeParent, "", &DT);
- }
- // Now that 'ret' has unique predecessor we can safely remove all phi nodes
+ // Now that 'Ret' has unique predecessor we can safely remove all phi nodes
// from it
FoldSingleEntryPHINodes(Ret);
- assert(!isa<PHINode>(Ret->begin()));
+ assert(!isa<PHINode>(Ret->begin()) &&
+ "All PHI nodes should have been removed!");
- // At this point, we can safely insert a gc.relocate as the first instruction
- // in Ret if needed.
+ // At this point, we can safely insert a gc.relocate or gc.result as the first
+ // instruction in Ret if needed.
return Ret;
}
-static int find_index(ArrayRef<Value *> livevec, Value *val) {
- auto itr = std::find(livevec.begin(), livevec.end(), val);
- assert(livevec.end() != itr);
- size_t index = std::distance(livevec.begin(), itr);
- assert(index < livevec.size());
- return index;
-}
-
// Create new attribute set containing only attributes which can be transferred
// from original call to the safepoint.
static AttributeSet legalizeCallAttributes(AttributeSet AS) {
- AttributeSet ret;
+ AttributeSet Ret;
for (unsigned Slot = 0; Slot < AS.getNumSlots(); Slot++) {
- unsigned index = AS.getSlotIndex(Slot);
+ unsigned Index = AS.getSlotIndex(Slot);
- if (index == AttributeSet::ReturnIndex ||
- index == AttributeSet::FunctionIndex) {
+ if (Index == AttributeSet::ReturnIndex ||
+ Index == AttributeSet::FunctionIndex) {
- for (auto it = AS.begin(Slot), it_end = AS.end(Slot); it != it_end;
- ++it) {
- Attribute attr = *it;
+ for (Attribute Attr : make_range(AS.begin(Slot), AS.end(Slot))) {
// Do not allow certain attributes - just skip them
// Safepoint can not be read only or read none.
- if (attr.hasAttribute(Attribute::ReadNone) ||
- attr.hasAttribute(Attribute::ReadOnly))
+ if (Attr.hasAttribute(Attribute::ReadNone) ||
+ Attr.hasAttribute(Attribute::ReadOnly))
continue;
- ret = ret.addAttributes(
- AS.getContext(), index,
- AttributeSet::get(AS.getContext(), index, AttrBuilder(attr)));
+ // These attributes control the generation of the gc.statepoint call /
+ // invoke itself; and once the gc.statepoint is in place, they're of no
+ // use.
+ if (Attr.hasAttribute("statepoint-num-patch-bytes") ||
+ Attr.hasAttribute("statepoint-id"))
+ continue;
+
+ Ret = Ret.addAttributes(
+ AS.getContext(), Index,
+ AttributeSet::get(AS.getContext(), Index, AttrBuilder(Attr)));
}
}
// Just skip parameter attributes for now
}
- return ret;
+ return Ret;
}
/// Helper function to place all gc relocates necessary for the given
/// statepointToken - statepoint instruction to which relocates should be
/// bound.
/// Builder - Llvm IR builder to be used to construct new calls.
-static void CreateGCRelocates(ArrayRef<llvm::Value *> LiveVariables,
+static void CreateGCRelocates(ArrayRef<Value *> LiveVariables,
const int LiveStart,
- ArrayRef<llvm::Value *> BasePtrs,
+ ArrayRef<Value *> BasePtrs,
Instruction *StatepointToken,
IRBuilder<> Builder) {
if (LiveVariables.empty())
return;
-
+
+ auto FindIndex = [](ArrayRef<Value *> LiveVec, Value *Val) {
+ auto ValIt = std::find(LiveVec.begin(), LiveVec.end(), Val);
+ assert(ValIt != LiveVec.end() && "Val not found in LiveVec!");
+ size_t Index = std::distance(LiveVec.begin(), ValIt);
+ assert(Index < LiveVec.size() && "Bug in std::find?");
+ return Index;
+ };
+
// All gc_relocate are set to i8 addrspace(1)* type. We originally generated
// unique declarations for each pointer type, but this proved problematic
// because the intrinsic mangling code is incomplete and fragile. Since
for (unsigned i = 0; i < LiveVariables.size(); i++) {
// Generate the gc.relocate call and save the result
Value *BaseIdx =
- Builder.getInt32(LiveStart + find_index(LiveVariables, BasePtrs[i]));
- Value *LiveIdx =
- Builder.getInt32(LiveStart + find_index(LiveVariables, LiveVariables[i]));
+ Builder.getInt32(LiveStart + FindIndex(LiveVariables, BasePtrs[i]));
+ Value *LiveIdx = Builder.getInt32(LiveStart + i);
// only specify a debug name if we can give a useful one
CallInst *Reloc = Builder.CreateCall(
}
}
-static void
-makeStatepointExplicitImpl(const CallSite &CS, /* to replace */
- const SmallVectorImpl<llvm::Value *> &basePtrs,
- const SmallVectorImpl<llvm::Value *> &liveVariables,
- Pass *P,
- PartiallyConstructedSafepointRecord &result) {
- assert(basePtrs.size() == liveVariables.size());
- assert(isStatepoint(CS) &&
- "This method expects to be rewriting a statepoint");
+namespace {
- BasicBlock *BB = CS.getInstruction()->getParent();
- assert(BB);
- Function *F = BB->getParent();
- assert(F && "must be set");
- Module *M = F->getParent();
- (void)M;
- assert(M && "must be set");
+/// This struct is used to defer RAUWs and `eraseFromParent` s. Using this
+/// avoids having to worry about keeping around dangling pointers to Values.
+class DeferredReplacement {
+ AssertingVH<Instruction> Old;
+ AssertingVH<Instruction> New;
- // We're not changing the function signature of the statepoint since the gc
- // arguments go into the var args section.
- Function *gc_statepoint_decl = CS.getCalledFunction();
+public:
+ explicit DeferredReplacement(Instruction *Old, Instruction *New) :
+ Old(Old), New(New) {
+ assert(Old != New && "Not allowed!");
+ }
+
+ /// Does the task represented by this instance.
+ void doReplacement() {
+ Instruction *OldI = Old;
+ Instruction *NewI = New;
+
+ assert(OldI != NewI && "Disallowed at construction?!");
+
+ Old = nullptr;
+ New = nullptr;
+
+ if (NewI)
+ OldI->replaceAllUsesWith(NewI);
+ OldI->eraseFromParent();
+ }
+};
+}
+
+static void
+makeStatepointExplicitImpl(const CallSite CS, /* to replace */
+ const SmallVectorImpl<Value *> &BasePtrs,
+ const SmallVectorImpl<Value *> &LiveVariables,
+ PartiallyConstructedSafepointRecord &Result,
+ std::vector<DeferredReplacement> &Replacements) {
+ assert(BasePtrs.size() == LiveVariables.size());
+ assert((UseDeoptBundles || isStatepoint(CS)) &&
+ "This method expects to be rewriting a statepoint");
// Then go ahead and use the builder do actually do the inserts. We insert
// immediately before the previous instruction under the assumption that all
// arguments will be available here. We can't insert afterwards since we may
// be replacing a terminator.
- Instruction *insertBefore = CS.getInstruction();
- IRBuilder<> Builder(insertBefore);
- // Copy all of the arguments from the original statepoint - this includes the
- // target, call args, and deopt args
- SmallVector<llvm::Value *, 64> args;
- args.insert(args.end(), CS.arg_begin(), CS.arg_end());
- // TODO: Clear the 'needs rewrite' flag
-
- // add all the pointers to be relocated (gc arguments)
- // Capture the start of the live variable list for use in the gc_relocates
- const int live_start = args.size();
- args.insert(args.end(), liveVariables.begin(), liveVariables.end());
+ Instruction *InsertBefore = CS.getInstruction();
+ IRBuilder<> Builder(InsertBefore);
+
+ ArrayRef<Value *> GCArgs(LiveVariables);
+ uint64_t StatepointID = 0xABCDEF00;
+ uint32_t NumPatchBytes = 0;
+ uint32_t Flags = uint32_t(StatepointFlags::None);
+
+ ArrayRef<Use> CallArgs;
+ ArrayRef<Use> DeoptArgs;
+ ArrayRef<Use> TransitionArgs;
+
+ Value *CallTarget = nullptr;
+
+ if (UseDeoptBundles) {
+ CallArgs = {CS.arg_begin(), CS.arg_end()};
+ DeoptArgs = GetDeoptBundleOperands(CS);
+ // TODO: we don't fill in TransitionArgs or Flags in this branch, but we
+ // could have an operand bundle for that too.
+ AttributeSet OriginalAttrs = CS.getAttributes();
+
+ Attribute AttrID = OriginalAttrs.getAttribute(AttributeSet::FunctionIndex,
+ "statepoint-id");
+ if (AttrID.isStringAttribute())
+ AttrID.getValueAsString().getAsInteger(10, StatepointID);
+
+ Attribute AttrNumPatchBytes = OriginalAttrs.getAttribute(
+ AttributeSet::FunctionIndex, "statepoint-num-patch-bytes");
+ if (AttrNumPatchBytes.isStringAttribute())
+ AttrNumPatchBytes.getValueAsString().getAsInteger(10, NumPatchBytes);
+
+ CallTarget = CS.getCalledValue();
+ } else {
+ // This branch will be gone soon, and we will soon only support the
+ // UseDeoptBundles == true configuration.
+ Statepoint OldSP(CS);
+ StatepointID = OldSP.getID();
+ NumPatchBytes = OldSP.getNumPatchBytes();
+ Flags = OldSP.getFlags();
+
+ CallArgs = {OldSP.arg_begin(), OldSP.arg_end()};
+ DeoptArgs = {OldSP.vm_state_begin(), OldSP.vm_state_end()};
+ TransitionArgs = {OldSP.gc_transition_args_begin(),
+ OldSP.gc_transition_args_end()};
+ CallTarget = OldSP.getCalledValue();
+ }
// Create the statepoint given all the arguments
- Instruction *token = nullptr;
- AttributeSet return_attributes;
+ Instruction *Token = nullptr;
+ AttributeSet ReturnAttrs;
if (CS.isCall()) {
- CallInst *toReplace = cast<CallInst>(CS.getInstruction());
- CallInst *call =
- Builder.CreateCall(gc_statepoint_decl, args, "safepoint_token");
- call->setTailCall(toReplace->isTailCall());
- call->setCallingConv(toReplace->getCallingConv());
+ CallInst *ToReplace = cast<CallInst>(CS.getInstruction());
+ CallInst *Call = Builder.CreateGCStatepointCall(
+ StatepointID, NumPatchBytes, CallTarget, Flags, CallArgs,
+ TransitionArgs, DeoptArgs, GCArgs, "safepoint_token");
+
+ Call->setTailCall(ToReplace->isTailCall());
+ Call->setCallingConv(ToReplace->getCallingConv());
// Currently we will fail on parameter attributes and on certain
// function attributes.
- AttributeSet new_attrs = legalizeCallAttributes(toReplace->getAttributes());
+ AttributeSet NewAttrs = legalizeCallAttributes(ToReplace->getAttributes());
// In case if we can handle this set of attributes - set up function attrs
// directly on statepoint and return attrs later for gc_result intrinsic.
- call->setAttributes(new_attrs.getFnAttributes());
- return_attributes = new_attrs.getRetAttributes();
+ Call->setAttributes(NewAttrs.getFnAttributes());
+ ReturnAttrs = NewAttrs.getRetAttributes();
- token = call;
+ Token = Call;
// Put the following gc_result and gc_relocate calls immediately after the
// the old call (which we're about to delete)
- BasicBlock::iterator next(toReplace);
- assert(BB->end() != next && "not a terminator, must have next");
- next++;
- Instruction *IP = &*(next);
- Builder.SetInsertPoint(IP);
- Builder.SetCurrentDebugLocation(IP->getDebugLoc());
-
+ assert(ToReplace->getNextNode() && "Not a terminator, must have next!");
+ Builder.SetInsertPoint(ToReplace->getNextNode());
+ Builder.SetCurrentDebugLocation(ToReplace->getNextNode()->getDebugLoc());
} else {
- InvokeInst *toReplace = cast<InvokeInst>(CS.getInstruction());
+ InvokeInst *ToReplace = cast<InvokeInst>(CS.getInstruction());
// Insert the new invoke into the old block. We'll remove the old one in a
// moment at which point this will become the new terminator for the
// original block.
- InvokeInst *invoke = InvokeInst::Create(
- gc_statepoint_decl, toReplace->getNormalDest(),
- toReplace->getUnwindDest(), args, "statepoint_token", toReplace->getParent());
- invoke->setCallingConv(toReplace->getCallingConv());
+ InvokeInst *Invoke = Builder.CreateGCStatepointInvoke(
+ StatepointID, NumPatchBytes, CallTarget, ToReplace->getNormalDest(),
+ ToReplace->getUnwindDest(), Flags, CallArgs, TransitionArgs, DeoptArgs,
+ GCArgs, "statepoint_token");
+
+ Invoke->setCallingConv(ToReplace->getCallingConv());
// Currently we will fail on parameter attributes and on certain
// function attributes.
- AttributeSet new_attrs = legalizeCallAttributes(toReplace->getAttributes());
+ AttributeSet NewAttrs = legalizeCallAttributes(ToReplace->getAttributes());
// In case if we can handle this set of attributes - set up function attrs
// directly on statepoint and return attrs later for gc_result intrinsic.
- invoke->setAttributes(new_attrs.getFnAttributes());
- return_attributes = new_attrs.getRetAttributes();
+ Invoke->setAttributes(NewAttrs.getFnAttributes());
+ ReturnAttrs = NewAttrs.getRetAttributes();
- token = invoke;
+ Token = Invoke;
// Generate gc relocates in exceptional path
- BasicBlock *unwindBlock = toReplace->getUnwindDest();
- assert(!isa<PHINode>(unwindBlock->begin()) &&
- unwindBlock->getUniquePredecessor() &&
+ BasicBlock *UnwindBlock = ToReplace->getUnwindDest();
+ assert(!isa<PHINode>(UnwindBlock->begin()) &&
+ UnwindBlock->getUniquePredecessor() &&
"can't safely insert in this block!");
- Instruction *IP = &*(unwindBlock->getFirstInsertionPt());
- Builder.SetInsertPoint(IP);
- Builder.SetCurrentDebugLocation(toReplace->getDebugLoc());
+ Builder.SetInsertPoint(&*UnwindBlock->getFirstInsertionPt());
+ Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
- // Extract second element from landingpad return value. We will attach
- // exceptional gc relocates to it.
- const unsigned idx = 1;
- Instruction *exceptional_token =
- cast<Instruction>(Builder.CreateExtractValue(
- unwindBlock->getLandingPadInst(), idx, "relocate_token"));
- result.UnwindToken = exceptional_token;
+ // Attach exceptional gc relocates to the landingpad.
+ Instruction *ExceptionalToken = UnwindBlock->getLandingPadInst();
+ Result.UnwindToken = ExceptionalToken;
- CreateGCRelocates(liveVariables, live_start, basePtrs,
- exceptional_token, Builder);
+ const unsigned LiveStartIdx = Statepoint(Token).gcArgsStartIdx();
+ CreateGCRelocates(LiveVariables, LiveStartIdx, BasePtrs, ExceptionalToken,
+ Builder);
// Generate gc relocates and returns for normal block
- BasicBlock *normalDest = toReplace->getNormalDest();
- assert(!isa<PHINode>(normalDest->begin()) &&
- normalDest->getUniquePredecessor() &&
+ BasicBlock *NormalDest = ToReplace->getNormalDest();
+ assert(!isa<PHINode>(NormalDest->begin()) &&
+ NormalDest->getUniquePredecessor() &&
"can't safely insert in this block!");
- IP = &*(normalDest->getFirstInsertionPt());
- Builder.SetInsertPoint(IP);
+ Builder.SetInsertPoint(&*NormalDest->getFirstInsertionPt());
// gc relocates will be generated later as if it were regular call
// statepoint
}
- assert(token);
+ assert(Token && "Should be set in one of the above branches!");
+
+ if (UseDeoptBundles) {
+ Token->setName("statepoint_token");
+ if (!CS.getType()->isVoidTy() && !CS.getInstruction()->use_empty()) {
+ StringRef Name =
+ CS.getInstruction()->hasName() ? CS.getInstruction()->getName() : "";
+ CallInst *GCResult = Builder.CreateGCResult(Token, CS.getType(), Name);
+ GCResult->setAttributes(CS.getAttributes().getRetAttributes());
+
+ // We cannot RAUW or delete CS.getInstruction() because it could be in the
+ // live set of some other safepoint, in which case that safepoint's
+ // PartiallyConstructedSafepointRecord will hold a raw pointer to this
+ // llvm::Instruction. Instead, we defer the replacement and deletion to
+ // after the live sets have been made explicit in the IR, and we no longer
+ // have raw pointers to worry about.
+ Replacements.emplace_back(CS.getInstruction(), GCResult);
+ } else {
+ Replacements.emplace_back(CS.getInstruction(), nullptr);
+ }
+ } else {
+ assert(!CS.getInstruction()->hasNUsesOrMore(2) &&
+ "only valid use before rewrite is gc.result");
+ assert(!CS.getInstruction()->hasOneUse() ||
+ isGCResult(cast<Instruction>(*CS.getInstruction()->user_begin())));
- // Take the name of the original value call if it had one.
- token->takeName(CS.getInstruction());
+ // Take the name of the original statepoint token if there was one.
+ Token->takeName(CS.getInstruction());
-// The GCResult is already inserted, we just need to find it
-#ifndef NDEBUG
- Instruction *toReplace = CS.getInstruction();
- assert((toReplace->hasNUses(0) || toReplace->hasNUses(1)) &&
- "only valid use before rewrite is gc.result");
- assert(!toReplace->hasOneUse() ||
- isGCResult(cast<Instruction>(*toReplace->user_begin())));
-#endif
-
- // Update the gc.result of the original statepoint (if any) to use the newly
- // inserted statepoint. This is safe to do here since the token can't be
- // considered a live reference.
- CS.getInstruction()->replaceAllUsesWith(token);
+ // Update the gc.result of the original statepoint (if any) to use the newly
+ // inserted statepoint. This is safe to do here since the token can't be
+ // considered a live reference.
+ CS.getInstruction()->replaceAllUsesWith(Token);
+ CS.getInstruction()->eraseFromParent();
+ }
- result.StatepointToken = token;
+ Result.StatepointToken = Token;
// Second, create a gc.relocate for every live variable
- CreateGCRelocates(liveVariables, live_start, basePtrs, token, Builder);
+ const unsigned LiveStartIdx = Statepoint(Token).gcArgsStartIdx();
+ CreateGCRelocates(LiveVariables, LiveStartIdx, BasePtrs, Token, Builder);
}
namespace {
-struct name_ordering {
- Value *base;
- Value *derived;
- bool operator()(name_ordering const &a, name_ordering const &b) {
- return -1 == a.derived->getName().compare(b.derived->getName());
+struct NameOrdering {
+ Value *Base;
+ Value *Derived;
+
+ bool operator()(NameOrdering const &a, NameOrdering const &b) {
+ return -1 == a.Derived->getName().compare(b.Derived->getName());
}
};
}
-static void stablize_order(SmallVectorImpl<Value *> &basevec,
- SmallVectorImpl<Value *> &livevec) {
- assert(basevec.size() == livevec.size());
-
- SmallVector<name_ordering, 64> temp;
- for (size_t i = 0; i < basevec.size(); i++) {
- name_ordering v;
- v.base = basevec[i];
- v.derived = livevec[i];
- temp.push_back(v);
- }
- std::sort(temp.begin(), temp.end(), name_ordering());
- for (size_t i = 0; i < basevec.size(); i++) {
- basevec[i] = temp[i].base;
- livevec[i] = temp[i].derived;
+
+static void StabilizeOrder(SmallVectorImpl<Value *> &BaseVec,
+ SmallVectorImpl<Value *> &LiveVec) {
+ assert(BaseVec.size() == LiveVec.size());
+
+ SmallVector<NameOrdering, 64> Temp;
+ for (size_t i = 0; i < BaseVec.size(); i++) {
+ NameOrdering v;
+ v.Base = BaseVec[i];
+ v.Derived = LiveVec[i];
+ Temp.push_back(v);
+ }
+
+ std::sort(Temp.begin(), Temp.end(), NameOrdering());
+ for (size_t i = 0; i < BaseVec.size(); i++) {
+ BaseVec[i] = Temp[i].Base;
+ LiveVec[i] = Temp[i].Derived;
}
}
// WARNING: Does not do any fixup to adjust users of the original live
// values. That's the callers responsibility.
static void
-makeStatepointExplicit(DominatorTree &DT, const CallSite &CS, Pass *P,
- PartiallyConstructedSafepointRecord &result) {
- auto liveset = result.liveset;
- auto PointerToBase = result.PointerToBase;
+makeStatepointExplicit(DominatorTree &DT, const CallSite &CS,
+ PartiallyConstructedSafepointRecord &Result,
+ std::vector<DeferredReplacement> &Replacements) {
+ const auto &LiveSet = Result.LiveSet;
+ const auto &PointerToBase = Result.PointerToBase;
// Convert to vector for efficient cross referencing.
- SmallVector<Value *, 64> basevec, livevec;
- livevec.reserve(liveset.size());
- basevec.reserve(liveset.size());
- for (Value *L : liveset) {
- livevec.push_back(L);
+ SmallVector<Value *, 64> BaseVec, LiveVec;
+ LiveVec.reserve(LiveSet.size());
+ BaseVec.reserve(LiveSet.size());
+ for (Value *L : LiveSet) {
+ LiveVec.push_back(L);
assert(PointerToBase.count(L));
- Value *base = PointerToBase[L];
- basevec.push_back(base);
+ Value *Base = PointerToBase.find(L)->second;
+ BaseVec.push_back(Base);
}
- assert(livevec.size() == basevec.size());
+ assert(LiveVec.size() == BaseVec.size());
// To make the output IR slightly more stable (for use in diffs), ensure a
// fixed order of the values in the safepoint (by sorting the value name).
// The order is otherwise meaningless.
- stablize_order(basevec, livevec);
+ StabilizeOrder(BaseVec, LiveVec);
// Do the actual rewriting and delete the old statepoint
- makeStatepointExplicitImpl(CS, basevec, livevec, P, result);
- CS.getInstruction()->eraseFromParent();
+ makeStatepointExplicitImpl(CS, BaseVec, LiveVec, Result, Replacements);
}
// Helper function for the relocationViaAlloca.
-// It receives iterator to the statepoint gc relocates and emits store to the
-// assigned
-// location (via allocaMap) for the each one of them.
-// Add visited values into the visitedLiveValues set we will later use them
-// for sanity check.
+//
+// It receives iterator to the statepoint gc relocates and emits a store to the
+// assigned location (via allocaMap) for the each one of them. It adds the
+// visited values into the visitedLiveValues set, which we will later use them
+// for sanity checking.
static void
insertRelocationStores(iterator_range<Value::user_iterator> GCRelocs,
DenseMap<Value *, Value *> &AllocaMap,
Value *Alloca = AllocaMap[OriginalValue];
// Emit store into the related alloca
- // All gc_relocate are i8 addrspace(1)* typed, and it must be bitcasted to
+ // All gc_relocates are i8 addrspace(1)* typed, and it must be bitcasted to
// the correct type according to alloca.
- assert(RelocatedValue->getNextNode() && "Should always have one since it's not a terminator");
+ assert(RelocatedValue->getNextNode() &&
+ "Should always have one since it's not a terminator");
IRBuilder<> Builder(RelocatedValue->getNextNode());
Value *CastedRelocatedValue =
Builder.CreateBitCast(RelocatedValue,
}
}
-/// do all the relocation update via allocas and mem2reg
+/// Do all the relocation update via allocas and mem2reg
static void relocationViaAlloca(
Function &F, DominatorTree &DT, ArrayRef<Value *> Live,
- ArrayRef<struct PartiallyConstructedSafepointRecord> Records) {
+ ArrayRef<PartiallyConstructedSafepointRecord> Records) {
#ifndef NDEBUG
// record initial number of (static) allocas; we'll check we have the same
// number when we get done.
PromotableAllocas.push_back(Alloca);
};
- // emit alloca for each live gc pointer
- for (unsigned i = 0; i < Live.size(); i++) {
- emitAllocaFor(Live[i]);
- }
-
- // emit allocas for rematerialized values
- for (size_t i = 0; i < Records.size(); i++) {
- const struct PartiallyConstructedSafepointRecord &Info = Records[i];
+ // Emit alloca for each live gc pointer
+ for (Value *V : Live)
+ emitAllocaFor(V);
+ // Emit allocas for rematerialized values
+ for (const auto &Info : Records)
for (auto RematerializedValuePair : Info.RematerializedValues) {
Value *OriginalValue = RematerializedValuePair.second;
if (AllocaMap.count(OriginalValue) != 0)
emitAllocaFor(OriginalValue);
++NumRematerializedValues;
}
- }
// The next two loops are part of the same conceptual operation. We need to
// insert a store to the alloca after the original def and at each
// redefinition. We need to insert a load before each use. These are split
// into distinct loops for performance reasons.
- // update gc pointer after each statepoint
- // either store a relocated value or null (if no relocated value found for
- // this gc pointer and it is not a gc_result)
- // this must happen before we update the statepoint with load of alloca
- // otherwise we lose the link between statepoint and old def
- for (size_t i = 0; i < Records.size(); i++) {
- const struct PartiallyConstructedSafepointRecord &Info = Records[i];
+ // Update gc pointer after each statepoint: either store a relocated value or
+ // null (if no relocated value was found for this gc pointer and it is not a
+ // gc_result). This must happen before we update the statepoint with load of
+ // alloca otherwise we lose the link between statepoint and old def.
+ for (const auto &Info : Records) {
Value *Statepoint = Info.StatepointToken;
// This will be used for consistency check
// Insert the clobbering stores. These may get intermixed with the
// gc.results and gc.relocates, but that's fine.
if (auto II = dyn_cast<InvokeInst>(Statepoint)) {
- InsertClobbersAt(II->getNormalDest()->getFirstInsertionPt());
- InsertClobbersAt(II->getUnwindDest()->getFirstInsertionPt());
+ InsertClobbersAt(&*II->getNormalDest()->getFirstInsertionPt());
+ InsertClobbersAt(&*II->getUnwindDest()->getFirstInsertionPt());
} else {
- BasicBlock::iterator Next(cast<CallInst>(Statepoint));
- Next++;
- InsertClobbersAt(Next);
+ InsertClobbersAt(cast<Instruction>(Statepoint)->getNextNode());
}
}
}
- // update use with load allocas and add store for gc_relocated
+
+ // Update use with load allocas and add store for gc_relocated.
for (auto Pair : AllocaMap) {
Value *Def = Pair.first;
Value *Alloca = Pair.second;
- // we pre-record the uses of allocas so that we dont have to worry about
- // later update
- // that change the user information.
+ // We pre-record the uses of allocas so that we dont have to worry about
+ // later update that changes the user information..
+
SmallVector<Instruction *, 20> Uses;
// PERF: trade a linear scan for repeated reallocation
Uses.reserve(std::distance(Def->user_begin(), Def->user_end()));
}
}
- // emit store for the initial gc value
- // store must be inserted after load, otherwise store will be in alloca's
- // use list and an extra load will be inserted before it
+ // Emit store for the initial gc value. Store must be inserted after load,
+ // otherwise store will be in alloca's use list and an extra load will be
+ // inserted before it.
StoreInst *Store = new StoreInst(Def, Alloca);
if (Instruction *Inst = dyn_cast<Instruction>(Def)) {
if (InvokeInst *Invoke = dyn_cast<InvokeInst>(Inst)) {
assert(PromotableAllocas.size() == Live.size() + NumRematerializedValues &&
"we must have the same allocas with lives");
if (!PromotableAllocas.empty()) {
- // apply mem2reg to promote alloca to SSA
+ // Apply mem2reg to promote alloca to SSA
PromoteMemToReg(PromotableAllocas, DT);
}
#ifndef NDEBUG
- for (auto I = F.getEntryBlock().begin(), E = F.getEntryBlock().end(); I != E;
- I++)
- if (isa<AllocaInst>(*I))
+ for (auto &I : F.getEntryBlock())
+ if (isa<AllocaInst>(I))
InitialAllocaNum--;
assert(InitialAllocaNum == 0 && "We must not introduce any extra allocas");
#endif
// No values to hold live, might as well not insert the empty holder
return;
- Module *M = CS.getInstruction()->getParent()->getParent()->getParent();
+ Module *M = CS.getInstruction()->getModule();
// Use a dummy vararg function to actually hold the values live
Function *Func = cast<Function>(M->getOrInsertFunction(
"__tmp_use", FunctionType::get(Type::getVoidTy(M->getContext()), true)));
if (CS.isCall()) {
// For call safepoints insert dummy calls right after safepoint
- BasicBlock::iterator Next(CS.getInstruction());
- Next++;
- Holders.push_back(CallInst::Create(Func, Values, "", Next));
+ Holders.push_back(CallInst::Create(Func, Values, "",
+ &*++CS.getInstruction()->getIterator()));
return;
}
// For invoke safepooints insert dummy calls both in normal and
// exceptional destination blocks
auto *II = cast<InvokeInst>(CS.getInstruction());
Holders.push_back(CallInst::Create(
- Func, Values, "", II->getNormalDest()->getFirstInsertionPt()));
+ Func, Values, "", &*II->getNormalDest()->getFirstInsertionPt()));
Holders.push_back(CallInst::Create(
- Func, Values, "", II->getUnwindDest()->getFirstInsertionPt()));
+ Func, Values, "", &*II->getUnwindDest()->getFirstInsertionPt()));
}
static void findLiveReferences(
- Function &F, DominatorTree &DT, Pass *P, ArrayRef<CallSite> toUpdate,
+ Function &F, DominatorTree &DT, ArrayRef<CallSite> toUpdate,
MutableArrayRef<struct PartiallyConstructedSafepointRecord> records) {
GCPtrLivenessData OriginalLivenessData;
computeLiveInValues(DT, F, OriginalLivenessData);
}
}
-/// Remove any vector of pointers from the liveset by scalarizing them over the
-/// statepoint instruction. Adds the scalarized pieces to the liveset. It
+/// Remove any vector of pointers from the live set by scalarizing them over the
+/// statepoint instruction. Adds the scalarized pieces to the live set. It
/// would be preferable to include the vector in the statepoint itself, but
/// the lowering code currently does not handle that. Extending it would be
/// slightly non-trivial since it requires a format change. Given how rare
}
if (CastInst *CI = dyn_cast<CastInst>(CurrentValue)) {
- Value *Def = CI->stripPointerCasts();
-
- // This two checks are basically similar. First one is here for the
- // consistency with findBasePointers logic.
- assert(!isa<CastInst>(Def) && "not a pointer cast found");
if (!CI->isNoopCast(CI->getModule()->getDataLayout()))
return false;
ChainToBase.push_back(CI);
- return findRematerializableChainToBasePointer(ChainToBase, Def, BaseValue);
+ return findRematerializableChainToBasePointer(ChainToBase,
+ CI->getOperand(0), BaseValue);
}
// Not supported instruction in the chain
return Cost;
}
-// From the statepoint liveset pick values that are cheaper to recompute then to
-// relocate. Remove this values from the liveset, rematerialize them after
+// From the statepoint live set pick values that are cheaper to recompute then
+// to relocate. Remove this values from the live set, rematerialize them after
// statepoint and record them in "Info" structure. Note that similar to
// relocated values we don't do any user adjustments here.
static void rematerializeLiveValues(CallSite CS,
// We can not di this in following loop due to iterator invalidation.
SmallVector<Value *, 32> LiveValuesToBeDeleted;
- for (Value *LiveValue: Info.liveset) {
+ for (Value *LiveValue: Info.LiveSet) {
// For each live pointer find it's defining chain
SmallVector<Instruction *, 3> ChainToBase;
assert(Info.PointerToBase.count(LiveValue));
InvokeInst *Invoke = cast<InvokeInst>(CS.getInstruction());
Instruction *NormalInsertBefore =
- Invoke->getNormalDest()->getFirstInsertionPt();
+ &*Invoke->getNormalDest()->getFirstInsertionPt();
Instruction *UnwindInsertBefore =
- Invoke->getUnwindDest()->getFirstInsertionPt();
+ &*Invoke->getUnwindDest()->getFirstInsertionPt();
Instruction *NormalRematerializedValue =
rematerializeChain(NormalInsertBefore);
// Remove rematerializaed values from the live set
for (auto LiveValue: LiveValuesToBeDeleted) {
- Info.liveset.erase(LiveValue);
+ Info.LiveSet.erase(LiveValue);
}
}
-static bool insertParsePoints(Function &F, DominatorTree &DT, Pass *P,
- SmallVectorImpl<CallSite> &toUpdate) {
+static bool insertParsePoints(Function &F, DominatorTree &DT,
+ TargetTransformInfo &TTI,
+ SmallVectorImpl<CallSite> &ToUpdate) {
#ifndef NDEBUG
// sanity check the input
- std::set<CallSite> uniqued;
- uniqued.insert(toUpdate.begin(), toUpdate.end());
- assert(uniqued.size() == toUpdate.size() && "no duplicates please!");
+ std::set<CallSite> Uniqued;
+ Uniqued.insert(ToUpdate.begin(), ToUpdate.end());
+ assert(Uniqued.size() == ToUpdate.size() && "no duplicates please!");
- for (size_t i = 0; i < toUpdate.size(); i++) {
- CallSite &CS = toUpdate[i];
+ for (CallSite CS : ToUpdate) {
assert(CS.getInstruction()->getParent()->getParent() == &F);
- assert(isStatepoint(CS) && "expected to already be a deopt statepoint");
+ assert((UseDeoptBundles || isStatepoint(CS)) &&
+ "expected to already be a deopt statepoint");
}
#endif
// the top of the successor blocks. See the comment on
// normalForInvokeSafepoint on exactly what is needed. Note that this step
// may restructure the CFG.
- for (CallSite CS : toUpdate) {
+ for (CallSite CS : ToUpdate) {
if (!CS.isInvoke())
continue;
- InvokeInst *invoke = cast<InvokeInst>(CS.getInstruction());
- normalizeForInvokeSafepoint(invoke->getNormalDest(), invoke->getParent(),
- DT);
- normalizeForInvokeSafepoint(invoke->getUnwindDest(), invoke->getParent(),
- DT);
+ auto *II = cast<InvokeInst>(CS.getInstruction());
+ normalizeForInvokeSafepoint(II->getNormalDest(), II->getParent(), DT);
+ normalizeForInvokeSafepoint(II->getUnwindDest(), II->getParent(), DT);
}
// A list of dummy calls added to the IR to keep various values obviously
// live in the IR. We'll remove all of these when done.
- SmallVector<CallInst *, 64> holders;
+ SmallVector<CallInst *, 64> Holders;
// Insert a dummy call with all of the arguments to the vm_state we'll need
// for the actual safepoint insertion. This ensures reference arguments in
// the deopt argument list are considered live through the safepoint (and
// thus makes sure they get relocated.)
- for (size_t i = 0; i < toUpdate.size(); i++) {
- CallSite &CS = toUpdate[i];
- Statepoint StatepointCS(CS);
-
+ for (CallSite CS : ToUpdate) {
SmallVector<Value *, 64> DeoptValues;
- for (Use &U : StatepointCS.vm_state_args()) {
- Value *Arg = cast<Value>(&U);
+
+ iterator_range<const Use *> DeoptStateRange =
+ UseDeoptBundles
+ ? iterator_range<const Use *>(GetDeoptBundleOperands(CS))
+ : iterator_range<const Use *>(Statepoint(CS).vm_state_args());
+
+ for (Value *Arg : DeoptStateRange) {
assert(!isUnhandledGCPointerType(Arg->getType()) &&
"support for FCA unimplemented");
if (isHandledGCPointerType(Arg->getType()))
DeoptValues.push_back(Arg);
}
- insertUseHolderAfter(CS, DeoptValues, holders);
- }
- SmallVector<struct PartiallyConstructedSafepointRecord, 64> records;
- records.reserve(toUpdate.size());
- for (size_t i = 0; i < toUpdate.size(); i++) {
- struct PartiallyConstructedSafepointRecord info;
- records.push_back(info);
+ insertUseHolderAfter(CS, DeoptValues, Holders);
}
- assert(records.size() == toUpdate.size());
+
+ SmallVector<PartiallyConstructedSafepointRecord, 64> Records(ToUpdate.size());
// A) Identify all gc pointers which are statically live at the given call
// site.
- findLiveReferences(F, DT, P, toUpdate, records);
+ findLiveReferences(F, DT, ToUpdate, Records);
// B) Find the base pointers for each live pointer
/* scope for caching */ {
// large numbers of duplicate base_phis.
DefiningValueMapTy DVCache;
- for (size_t i = 0; i < records.size(); i++) {
- struct PartiallyConstructedSafepointRecord &info = records[i];
- CallSite &CS = toUpdate[i];
- findBasePointers(DT, DVCache, CS, info);
+ for (size_t i = 0; i < Records.size(); i++) {
+ PartiallyConstructedSafepointRecord &info = Records[i];
+ findBasePointers(DT, DVCache, ToUpdate[i], info);
}
} // end of cache scope
// the base pointers which were identified for that safepoint. We'll then
// ask liveness for _every_ base inserted to see what is now live. Then we
// remove the dummy calls.
- holders.reserve(holders.size() + records.size());
- for (size_t i = 0; i < records.size(); i++) {
- struct PartiallyConstructedSafepointRecord &info = records[i];
- CallSite &CS = toUpdate[i];
+ Holders.reserve(Holders.size() + Records.size());
+ for (size_t i = 0; i < Records.size(); i++) {
+ PartiallyConstructedSafepointRecord &Info = Records[i];
SmallVector<Value *, 128> Bases;
- for (auto Pair : info.PointerToBase) {
+ for (auto Pair : Info.PointerToBase)
Bases.push_back(Pair.second);
- }
- insertUseHolderAfter(CS, Bases, holders);
+
+ insertUseHolderAfter(ToUpdate[i], Bases, Holders);
}
// By selecting base pointers, we've effectively inserted new uses. Thus, we
// need to rerun liveness. We may *also* have inserted new defs, but that's
// not the key issue.
- recomputeLiveInValues(F, DT, P, toUpdate, records);
+ recomputeLiveInValues(F, DT, ToUpdate, Records);
if (PrintBasePointers) {
- for (size_t i = 0; i < records.size(); i++) {
- struct PartiallyConstructedSafepointRecord &info = records[i];
+ for (auto &Info : Records) {
errs() << "Base Pairs: (w/Relocation)\n";
- for (auto Pair : info.PointerToBase) {
- errs() << " derived %" << Pair.first->getName() << " base %"
- << Pair.second->getName() << "\n";
+ for (auto Pair : Info.PointerToBase) {
+ errs() << " derived ";
+ Pair.first->printAsOperand(errs(), false);
+ errs() << " base ";
+ Pair.second->printAsOperand(errs(), false);
+ errs() << "\n";
}
}
}
- for (size_t i = 0; i < holders.size(); i++) {
- holders[i]->eraseFromParent();
- holders[i] = nullptr;
- }
- holders.clear();
+
+ // It is possible that non-constant live variables have a constant base. For
+ // example, a GEP with a variable offset from a global. In this case we can
+ // remove it from the liveset. We already don't add constants to the liveset
+ // because we assume they won't move at runtime and the GC doesn't need to be
+ // informed about them. The same reasoning applies if the base is constant.
+ // Note that the relocation placement code relies on this filtering for
+ // correctness as it expects the base to be in the liveset, which isn't true
+ // if the base is constant.
+ for (auto &Info : Records)
+ for (auto &BasePair : Info.PointerToBase)
+ if (isa<Constant>(BasePair.second))
+ Info.LiveSet.erase(BasePair.first);
+
+ for (CallInst *CI : Holders)
+ CI->eraseFromParent();
+
+ Holders.clear();
// Do a limited scalarization of any live at safepoint vector values which
// contain pointers. This enables this pass to run after vectorization at
// the cost of some possible performance loss. TODO: it would be nice to
// natively support vectors all the way through the backend so we don't need
// to scalarize here.
- for (size_t i = 0; i < records.size(); i++) {
- struct PartiallyConstructedSafepointRecord &info = records[i];
- Instruction *statepoint = toUpdate[i].getInstruction();
- splitVectorValues(cast<Instruction>(statepoint), info.liveset,
- info.PointerToBase, DT);
+ for (size_t i = 0; i < Records.size(); i++) {
+ PartiallyConstructedSafepointRecord &Info = Records[i];
+ Instruction *Statepoint = ToUpdate[i].getInstruction();
+ splitVectorValues(cast<Instruction>(Statepoint), Info.LiveSet,
+ Info.PointerToBase, DT);
}
// In order to reduce live set of statepoint we might choose to rematerialize
// some values instead of relocating them. This is purely an optimization and
// does not influence correctness.
- TargetTransformInfo &TTI =
- P->getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
-
- for (size_t i = 0; i < records.size(); i++) {
- struct PartiallyConstructedSafepointRecord &info = records[i];
- CallSite &CS = toUpdate[i];
+ for (size_t i = 0; i < Records.size(); i++)
+ rematerializeLiveValues(ToUpdate[i], Records[i], TTI);
- rematerializeLiveValues(CS, info, TTI);
- }
+ // We need this to safely RAUW and delete call or invoke return values that
+ // may themselves be live over a statepoint. For details, please see usage in
+ // makeStatepointExplicitImpl.
+ std::vector<DeferredReplacement> Replacements;
// Now run through and replace the existing statepoints with new ones with
// the live variables listed. We do not yet update uses of the values being
// survive to the last iteration of this loop. (By construction, the
// previous statepoint can not be a live variable, thus we can and remove
// the old statepoint calls as we go.)
- for (size_t i = 0; i < records.size(); i++) {
- struct PartiallyConstructedSafepointRecord &info = records[i];
- CallSite &CS = toUpdate[i];
- makeStatepointExplicit(DT, CS, P, info);
+ for (size_t i = 0; i < Records.size(); i++)
+ makeStatepointExplicit(DT, ToUpdate[i], Records[i], Replacements);
+
+ ToUpdate.clear(); // prevent accident use of invalid CallSites
+
+ for (auto &PR : Replacements)
+ PR.doReplacement();
+
+ Replacements.clear();
+
+ for (auto &Info : Records) {
+ // These live sets may contain state Value pointers, since we replaced calls
+ // with operand bundles with calls wrapped in gc.statepoint, and some of
+ // those calls may have been def'ing live gc pointers. Clear these out to
+ // avoid accidentally using them.
+ //
+ // TODO: We should create a separate data structure that does not contain
+ // these live sets, and migrate to using that data structure from this point
+ // onward.
+ Info.LiveSet.clear();
+ Info.PointerToBase.clear();
}
- toUpdate.clear(); // prevent accident use of invalid CallSites
// Do all the fixups of the original live variables to their relocated selves
- SmallVector<Value *, 128> live;
- for (size_t i = 0; i < records.size(); i++) {
- struct PartiallyConstructedSafepointRecord &info = records[i];
+ SmallVector<Value *, 128> Live;
+ for (size_t i = 0; i < Records.size(); i++) {
+ PartiallyConstructedSafepointRecord &Info = Records[i];
+
// We can't simply save the live set from the original insertion. One of
// the live values might be the result of a call which needs a safepoint.
// That Value* no longer exists and we need to use the new gc_result.
- // Thankfully, the liveset is embedded in the statepoint (and updated), so
+ // Thankfully, the live set is embedded in the statepoint (and updated), so
// we just grab that.
- Statepoint statepoint(info.StatepointToken);
- live.insert(live.end(), statepoint.gc_args_begin(),
- statepoint.gc_args_end());
+ Statepoint Statepoint(Info.StatepointToken);
+ Live.insert(Live.end(), Statepoint.gc_args_begin(),
+ Statepoint.gc_args_end());
#ifndef NDEBUG
// Do some basic sanity checks on our liveness results before performing
// relocation. Relocation can and will turn mistakes in liveness results
// into non-sensical code which is must harder to debug.
// TODO: It would be nice to test consistency as well
- assert(DT.isReachableFromEntry(info.StatepointToken->getParent()) &&
+ assert(DT.isReachableFromEntry(Info.StatepointToken->getParent()) &&
"statepoint must be reachable or liveness is meaningless");
- for (Value *V : statepoint.gc_args()) {
+ for (Value *V : Statepoint.gc_args()) {
if (!isa<Instruction>(V))
// Non-instruction values trivial dominate all possible uses
continue;
- auto LiveInst = cast<Instruction>(V);
+ auto *LiveInst = cast<Instruction>(V);
assert(DT.isReachableFromEntry(LiveInst->getParent()) &&
"unreachable values should never be live");
- assert(DT.dominates(LiveInst, info.StatepointToken) &&
+ assert(DT.dominates(LiveInst, Info.StatepointToken) &&
"basic SSA liveness expectation violated by liveness analysis");
}
#endif
}
- unique_unsorted(live);
+ unique_unsorted(Live);
#ifndef NDEBUG
// sanity check
- for (auto ptr : live) {
- assert(isGCPointerType(ptr->getType()) && "must be a gc pointer type");
- }
+ for (auto *Ptr : Live)
+ assert(isGCPointerType(Ptr->getType()) && "must be a gc pointer type");
#endif
- relocationViaAlloca(F, DT, live, records);
- return !records.empty();
+ relocationViaAlloca(F, DT, Live, Records);
+ return !Records.empty();
}
// Handles both return values and arguments for Functions and CallSites.
template <typename AttrHolder>
-static void RemoveDerefAttrAtIndex(LLVMContext &Ctx, AttrHolder &AH,
- unsigned Index) {
+static void RemoveNonValidAttrAtIndex(LLVMContext &Ctx, AttrHolder &AH,
+ unsigned Index) {
AttrBuilder R;
if (AH.getDereferenceableBytes(Index))
R.addAttribute(Attribute::get(Ctx, Attribute::Dereferenceable,
if (AH.getDereferenceableOrNullBytes(Index))
R.addAttribute(Attribute::get(Ctx, Attribute::DereferenceableOrNull,
AH.getDereferenceableOrNullBytes(Index)));
+ if (AH.doesNotAlias(Index))
+ R.addAttribute(Attribute::NoAlias);
if (!R.empty())
AH.setAttributes(AH.getAttributes().removeAttributes(
}
void
-RewriteStatepointsForGC::stripDereferenceabilityInfoFromPrototype(Function &F) {
+RewriteStatepointsForGC::stripNonValidAttributesFromPrototype(Function &F) {
LLVMContext &Ctx = F.getContext();
for (Argument &A : F.args())
if (isa<PointerType>(A.getType()))
- RemoveDerefAttrAtIndex(Ctx, F, A.getArgNo() + 1);
+ RemoveNonValidAttrAtIndex(Ctx, F, A.getArgNo() + 1);
if (isa<PointerType>(F.getReturnType()))
- RemoveDerefAttrAtIndex(Ctx, F, AttributeSet::ReturnIndex);
+ RemoveNonValidAttrAtIndex(Ctx, F, AttributeSet::ReturnIndex);
}
-void RewriteStatepointsForGC::stripDereferenceabilityInfoFromBody(Function &F) {
+void RewriteStatepointsForGC::stripNonValidAttributesFromBody(Function &F) {
if (F.empty())
return;
if (CallSite CS = CallSite(&I)) {
for (int i = 0, e = CS.arg_size(); i != e; i++)
if (isa<PointerType>(CS.getArgument(i)->getType()))
- RemoveDerefAttrAtIndex(Ctx, CS, i + 1);
+ RemoveNonValidAttrAtIndex(Ctx, CS, i + 1);
if (isa<PointerType>(CS.getType()))
- RemoveDerefAttrAtIndex(Ctx, CS, AttributeSet::ReturnIndex);
+ RemoveNonValidAttrAtIndex(Ctx, CS, AttributeSet::ReturnIndex);
}
}
}
return false;
}
-void RewriteStatepointsForGC::stripDereferenceabilityInfo(Module &M) {
+void RewriteStatepointsForGC::stripNonValidAttributes(Module &M) {
#ifndef NDEBUG
assert(std::any_of(M.begin(), M.end(), shouldRewriteStatepointsIn) &&
"precondition!");
#endif
for (Function &F : M)
- stripDereferenceabilityInfoFromPrototype(F);
+ stripNonValidAttributesFromPrototype(F);
for (Function &F : M)
- stripDereferenceabilityInfoFromBody(F);
+ stripNonValidAttributesFromBody(F);
}
bool RewriteStatepointsForGC::runOnFunction(Function &F) {
return false;
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
+ TargetTransformInfo &TTI =
+ getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
+
+ auto NeedsRewrite = [](Instruction &I) {
+ if (UseDeoptBundles) {
+ if (ImmutableCallSite CS = ImmutableCallSite(&I))
+ return !callsGCLeafFunction(CS);
+ return false;
+ }
+
+ return isStatepoint(I);
+ };
// Gather all the statepoints which need rewritten. Be careful to only
// consider those in reachable code since we need to ask dominance queries
bool HasUnreachableStatepoint = false;
for (Instruction &I : instructions(F)) {
// TODO: only the ones with the flag set!
- if (isStatepoint(I)) {
+ if (NeedsRewrite(I)) {
if (DT.isReachableFromEntry(I.getParent()))
ParsePointNeeded.push_back(CallSite(&I));
else
}
}
- MadeChange |= insertParsePoints(F, DT, this, ParsePointNeeded);
+ MadeChange |= insertParsePoints(F, DT, TTI, ParsePointNeeded);
return MadeChange;
}
// call result is not live (normal), nor are it's arguments
// (unless they're used again later). This adjustment is
// specifically what we need to relocate
- BasicBlock::reverse_iterator rend(Inst);
+ BasicBlock::reverse_iterator rend(Inst->getIterator());
computeLiveInValues(BB->rbegin(), rend, LiveOut);
LiveOut.erase(Inst);
Out.insert(LiveOut.begin(), LiveOut.end());
assert(Updated.count(KVPair.first) && "record for non-live value");
#endif
- Info.liveset = Updated;
+ Info.LiveSet = Updated;
}
projects / oota-llvm.git / blobdiff