STATISTIC(StatepointMaxSlotsRequired,
"Maximum number of stack slots required for a singe statepoint");
+static void pushStackMapConstant(SmallVectorImpl<SDValue>& Ops,
+ SelectionDAGBuilder &Builder, uint64_t Value) {
+ SDLoc L = Builder.getCurSDLoc();
+ Ops.push_back(Builder.DAG.getTargetConstant(StackMaps::ConstantOp, L,
+ MVT::i64));
+ Ops.push_back(Builder.DAG.getTargetConstant(Value, L, MVT::i64));
+}
+
void StatepointLoweringState::startNewStatepoint(SelectionDAGBuilder &Builder) {
// Consistency check
assert(PendingGCRelocateCalls.empty() &&
"Trying to visit statepoint before finished processing previous one");
Locations.clear();
- RelocLocations.clear();
NextSlotToAllocate = 0;
// Need to resize this on each safepoint - we need the two to stay in
// sync and the clear patterns of a SelectionDAGBuilder have no relation
AllocatedStackSlots[i] = false;
}
}
+
void StatepointLoweringState::clear() {
Locations.clear();
- RelocLocations.clear();
AllocatedStackSlots.clear();
assert(PendingGCRelocateCalls.empty() &&
"cleared before statepoint sequence completed");
// such in the stackmap. This is required so that the consumer can
// parse any internal format to the deopt state. It also handles null
// pointers and other constant pointers in GC states
- Ops.push_back(Builder.DAG.getTargetConstant(StackMaps::ConstantOp,
- Builder.getCurSDLoc(),
- MVT::i64));
- Ops.push_back(Builder.DAG.getTargetConstant(C->getSExtValue(),
- Builder.getCurSDLoc(),
- MVT::i64));
+ pushStackMapConstant(Ops, Builder, C->getSExtValue());
} else if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Incoming)) {
// This handles allocas as arguments to the statepoint (this is only
// really meaningful for a deopt value. For GC, we'd be trying to
// particular value. This is purely an optimization over the code below and
// doesn't change semantics at all. It is important for performance that we
// reserve slots for both deopt and gc values before lowering either.
- for (auto I = StatepointSite.vm_state_begin() + 1,
- E = StatepointSite.vm_state_end();
- I != E; ++I) {
- Value *V = *I;
+ for (const Value *V : StatepointSite.vm_state_args()) {
SDValue Incoming = Builder.getValue(V);
reservePreviousStackSlotForValue(Incoming, Builder);
}
- for (unsigned i = 0; i < Bases.size() * 2; ++i) {
- // Even elements will contain base, odd elements - derived ptr
- const Value *V = i % 2 ? Bases[i / 2] : Ptrs[i / 2];
- SDValue Incoming = Builder.getValue(V);
- reservePreviousStackSlotForValue(Incoming, Builder);
+ for (unsigned i = 0; i < Bases.size(); ++i) {
+ const Value *Base = Bases[i];
+ reservePreviousStackSlotForValue(Builder.getValue(Base), Builder);
+
+ const Value *Ptr = Ptrs[i];
+ reservePreviousStackSlotForValue(Builder.getValue(Ptr), Builder);
}
// First, prefix the list with the number of unique values to be
// lowered. Note that this is the number of *Values* not the
// number of SDValues required to lower them.
const int NumVMSArgs = StatepointSite.getNumTotalVMSArgs();
- Ops.push_back( Builder.DAG.getTargetConstant(StackMaps::ConstantOp,
- Builder.getCurSDLoc(),
- MVT::i64));
- Ops.push_back(Builder.DAG.getTargetConstant(NumVMSArgs, Builder.getCurSDLoc(),
- MVT::i64));
+ pushStackMapConstant(Ops, Builder, NumVMSArgs);
- assert(NumVMSArgs + 1 == std::distance(StatepointSite.vm_state_begin(),
- StatepointSite.vm_state_end()));
+ assert(NumVMSArgs == std::distance(StatepointSite.vm_state_begin(),
+ StatepointSite.vm_state_end()));
// The vm state arguments are lowered in an opaque manner. We do
// not know what type of values are contained within. We skip the
// explicitly just above. We could have left it in the loop and
// not done it explicitly, but it's far easier to understand this
// way.
- for (auto I = StatepointSite.vm_state_begin() + 1,
- E = StatepointSite.vm_state_end();
- I != E; ++I) {
- const Value *V = *I;
+ for (const Value *V : StatepointSite.vm_state_args()) {
SDValue Incoming = Builder.getValue(V);
lowerIncomingStatepointValue(Incoming, Ops, Builder);
}
// arrays interwoven with each (lowered) base pointer immediately followed by
// it's (lowered) derived pointer. i.e
// (base[0], ptr[0], base[1], ptr[1], ...)
- for (unsigned i = 0; i < Bases.size() * 2; ++i) {
- // Even elements will contain base, odd elements - derived ptr
- const Value *V = i % 2 ? Bases[i / 2] : Ptrs[i / 2];
- SDValue Incoming = Builder.getValue(V);
- lowerIncomingStatepointValue(Incoming, Ops, Builder);
+ for (unsigned i = 0; i < Bases.size(); ++i) {
+ const Value *Base = Bases[i];
+ lowerIncomingStatepointValue(Builder.getValue(Base), Ops, Builder);
+
+ const Value *Ptr = Ptrs[i];
+ lowerIncomingStatepointValue(Builder.getValue(Ptr), Ops, Builder);
}
// If there are any explicit spill slots passed to the statepoint, record
Incoming.getValueType()));
}
}
+
+ // Record computed locations for all lowered values.
+ // This can not be embedded in lowering loops as we need to record *all*
+ // values, while previous loops account only values with unique SDValues.
+ const Instruction *StatepointInstr =
+ StatepointSite.getCallSite().getInstruction();
+ FunctionLoweringInfo::StatepointSpilledValueMapTy &SpillMap =
+ Builder.FuncInfo.StatepointRelocatedValues[StatepointInstr];
+
+ for (GCRelocateOperands RelocateOpers :
+ StatepointSite.getRelocates(StatepointSite)) {
+ const Value *V = RelocateOpers.getDerivedPtr();
+ SDValue SDV = Builder.getValue(V);
+ SDValue Loc = Builder.StatepointLowering.getLocation(SDV);
+
+ if (Loc.getNode()) {
+ SpillMap[V] = cast<FrameIndexSDNode>(Loc)->getIndex();
+ } else {
+ // Record value as visited, but not spilled. This is case for allocas
+ // and constants. For this values we can avoid emiting spill load while
+ // visiting corresponding gc_relocate.
+ // Actually we do not need to record them in this map at all.
+ // We do this only to check that we are not relocating any unvisited value.
+ SpillMap[V] = None;
+
+ // Default llvm mechanisms for exporting values which are used in
+ // different basic blocks does not work for gc relocates.
+ // Note that it would be incorrect to teach llvm that all relocates are
+ // uses of the corresponging values so that it would automatically
+ // export them. Relocates of the spilled values does not use original
+ // value.
+ if (StatepointSite.getCallSite().isInvoke())
+ Builder.ExportFromCurrentBlock(V);
+ }
+ }
}
void SelectionDAGBuilder::visitStatepoint(const CallInst &CI) {
ImmutableCallSite CS(ISP.getCallSite());
#ifndef NDEBUG
- // Consistency check
- for (const User *U : CS->users()) {
- const CallInst *Call = cast<CallInst>(U);
- if (isGCRelocate(Call))
- StatepointLowering.scheduleRelocCall(*Call);
+ // Consistency check. Don't do this for invokes. It would be too
+ // expensive to preserve this information across different basic blocks
+ if (!CS.isInvoke()) {
+ for (const User *U : CS->users()) {
+ const CallInst *Call = cast<CallInst>(U);
+ if (isGCRelocate(Call))
+ StatepointLowering.scheduleRelocCall(*Call);
+ }
}
#endif
ISP.verify();
// Check that the associated GCStrategy expects to encounter statepoints.
- // TODO: This if should become an assert. For now, we allow the GCStrategy
- // to be optional for backwards compatibility. This will only last a short
- // period (i.e. a couple of weeks).
assert(GFI->getStrategy().useStatepoints() &&
"GCStrategy does not expect to encounter statepoints");
#endif
SDNode *CallNode =
lowerCallFromStatepoint(ISP, LandingPad, *this, PendingExports);
- // Construct the actual STATEPOINT node with all the appropriate arguments
- // and return values.
+ // Construct the actual GC_TRANSITION_START, STATEPOINT, and GC_TRANSITION_END
+ // nodes with all the appropriate arguments and return values.
+
+ // Call Node: Chain, Target, {Args}, RegMask, [Glue]
+ SDValue Chain = CallNode->getOperand(0);
+
+ SDValue Glue;
+ bool CallHasIncomingGlue = CallNode->getGluedNode();
+ if (CallHasIncomingGlue) {
+ // Glue is always last operand
+ Glue = CallNode->getOperand(CallNode->getNumOperands() - 1);
+ }
+
+ // Build the GC_TRANSITION_START node if necessary.
+ //
+ // The operands to the GC_TRANSITION_{START,END} nodes are laid out in the
+ // order in which they appear in the call to the statepoint intrinsic. If
+ // any of the operands is a pointer-typed, that operand is immediately
+ // followed by a SRCVALUE for the pointer that may be used during lowering
+ // (e.g. to form MachinePointerInfo values for loads/stores).
+ const bool IsGCTransition =
+ (ISP.getFlags() & (uint64_t)StatepointFlags::GCTransition) ==
+ (uint64_t)StatepointFlags::GCTransition;
+ if (IsGCTransition) {
+ SmallVector<SDValue, 8> TSOps;
+
+ // Add chain
+ TSOps.push_back(Chain);
+
+ // Add GC transition arguments
+ for (const Value *V : ISP.gc_transition_args()) {
+ TSOps.push_back(getValue(V));
+ if (V->getType()->isPointerTy())
+ TSOps.push_back(DAG.getSrcValue(V));
+ }
+
+ // Add glue if necessary
+ if (CallHasIncomingGlue)
+ TSOps.push_back(Glue);
+
+ SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
+
+ SDValue GCTransitionStart =
+ DAG.getNode(ISD::GC_TRANSITION_START, getCurSDLoc(), NodeTys, TSOps);
+
+ Chain = GCTransitionStart.getValue(0);
+ Glue = GCTransitionStart.getValue(1);
+ }
// TODO: Currently, all of these operands are being marked as read/write in
// PrologEpilougeInserter.cpp, we should special case the VMState arguments
// and flags to be read-only.
SmallVector<SDValue, 40> Ops;
+ // Add the <id> and <numBytes> constants.
+ Ops.push_back(DAG.getTargetConstant(ISP.getID(), getCurSDLoc(), MVT::i64));
+ Ops.push_back(
+ DAG.getTargetConstant(ISP.getNumPatchBytes(), getCurSDLoc(), MVT::i32));
+
// Calculate and push starting position of vmstate arguments
- // Call Node: Chain, Target, {Args}, RegMask, [Glue]
- SDValue Glue;
- if (CallNode->getGluedNode()) {
- // Glue is always last operand
- Glue = CallNode->getOperand(CallNode->getNumOperands() - 1);
- }
// Get number of arguments incoming directly into call node
unsigned NumCallRegArgs =
- CallNode->getNumOperands() - (Glue.getNode() ? 4 : 3);
+ CallNode->getNumOperands() - (CallHasIncomingGlue ? 4 : 3);
Ops.push_back(DAG.getTargetConstant(NumCallRegArgs, getCurSDLoc(), MVT::i32));
// Add call target
// Add call arguments
// Get position of register mask in the call
SDNode::op_iterator RegMaskIt;
- if (Glue.getNode())
+ if (CallHasIncomingGlue)
RegMaskIt = CallNode->op_end() - 2;
else
RegMaskIt = CallNode->op_end() - 1;
Ops.insert(Ops.end(), CallNode->op_begin() + 2, RegMaskIt);
- // Add a leading constant argument with the Flags and the calling convention
- // masked together
- CallingConv::ID CallConv = CS.getCallingConv();
- int Flags = cast<ConstantInt>(CS.getArgument(2))->getZExtValue();
- assert(Flags == 0 && "not expected to be used");
- Ops.push_back(DAG.getTargetConstant(StackMaps::ConstantOp, getCurSDLoc(),
- MVT::i64));
- Ops.push_back(DAG.getTargetConstant(Flags | ((unsigned)CallConv << 1),
- getCurSDLoc(), MVT::i64));
+ // Add a constant argument for the calling convention
+ pushStackMapConstant(Ops, *this, CS.getCallingConv());
+
+ // Add a constant argument for the flags
+ uint64_t Flags = ISP.getFlags();
+ assert(
+ ((Flags & ~(uint64_t)StatepointFlags::MaskAll) == 0)
+ && "unknown flag used");
+ pushStackMapConstant(Ops, *this, Flags);
// Insert all vmstate and gcstate arguments
Ops.insert(Ops.end(), LoweredMetaArgs.begin(), LoweredMetaArgs.end());
Ops.push_back(*RegMaskIt);
// Add chain
- Ops.push_back(CallNode->getOperand(0));
+ Ops.push_back(Chain);
// Same for the glue, but we add it only if original call had it
if (Glue.getNode())
SDNode *StatepointMCNode =
DAG.getMachineNode(TargetOpcode::STATEPOINT, getCurSDLoc(), NodeTys, Ops);
+ SDNode *SinkNode = StatepointMCNode;
+
+ // Build the GC_TRANSITION_END node if necessary.
+ //
+ // See the comment above regarding GC_TRANSITION_START for the layout of
+ // the operands to the GC_TRANSITION_END node.
+ if (IsGCTransition) {
+ SmallVector<SDValue, 8> TEOps;
+
+ // Add chain
+ TEOps.push_back(SDValue(StatepointMCNode, 0));
+
+ // Add GC transition arguments
+ for (const Value *V : ISP.gc_transition_args()) {
+ TEOps.push_back(getValue(V));
+ if (V->getType()->isPointerTy())
+ TEOps.push_back(DAG.getSrcValue(V));
+ }
+
+ // Add glue
+ TEOps.push_back(SDValue(StatepointMCNode, 1));
+
+ SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
+
+ SDValue GCTransitionStart =
+ DAG.getNode(ISD::GC_TRANSITION_END, getCurSDLoc(), NodeTys, TEOps);
+
+ SinkNode = GCTransitionStart.getNode();
+ }
+
// Replace original call
- DAG.ReplaceAllUsesWith(CallNode, StatepointMCNode); // This may update Root
+ DAG.ReplaceAllUsesWith(CallNode, SinkNode); // This may update Root
// Remove originall call node
DAG.DeleteNode(CallNode);
}
void SelectionDAGBuilder::visitGCRelocate(const CallInst &CI) {
+ GCRelocateOperands RelocateOpers(&CI);
+
#ifndef NDEBUG
// Consistency check
- StatepointLowering.relocCallVisited(CI);
+ // We skip this check for invoke statepoints. It would be too expensive to
+ // preserve validation info through different basic blocks.
+ if (!RelocateOpers.isTiedToInvoke()) {
+ StatepointLowering.relocCallVisited(CI);
+ }
#endif
- GCRelocateOperands relocateOpers(&CI);
- SDValue SD = getValue(relocateOpers.getDerivedPtr());
+ const Value *DerivedPtr = RelocateOpers.getDerivedPtr();
+ SDValue SD = getValue(DerivedPtr);
+
+ FunctionLoweringInfo::StatepointSpilledValueMapTy &SpillMap =
+ FuncInfo.StatepointRelocatedValues[RelocateOpers.getStatepoint()];
- if (isa<ConstantSDNode>(SD) || isa<FrameIndexSDNode>(SD)) {
- // We didn't need to spill these special cases (constants and allocas).
- // See the handling in spillIncomingValueForStatepoint for detail.
+ // We should have recorded location for this pointer
+ assert(SpillMap.count(DerivedPtr) && "Relocating not lowered gc value");
+ Optional<int> DerivedPtrLocation = SpillMap[DerivedPtr];
+
+ // We didn't need to spill these special cases (constants and allocas).
+ // See the handling in spillIncomingValueForStatepoint for detail.
+ if (!DerivedPtrLocation) {
setValue(&CI, SD);
return;
}
- SDValue Loc = StatepointLowering.getRelocLocation(SD);
- // Emit new load if we did not emit it before
- if (!Loc.getNode()) {
- SDValue SpillSlot = StatepointLowering.getLocation(SD);
- int FI = cast<FrameIndexSDNode>(SpillSlot)->getIndex();
+ SDValue SpillSlot = DAG.getTargetFrameIndex(*DerivedPtrLocation,
+ SD.getValueType());
- // Be conservative: flush all pending loads
- // TODO: Probably we can be less restrictive on this,
- // it may allow more scheduling opprtunities
- SDValue Chain = getRoot();
+ // Be conservative: flush all pending loads
+ // TODO: Probably we can be less restrictive on this,
+ // it may allow more scheduling opprtunities
+ SDValue Chain = getRoot();
- Loc = DAG.getLoad(SpillSlot.getValueType(), getCurSDLoc(), Chain, SpillSlot,
- MachinePointerInfo::getFixedStack(FI), false, false,
- false, 0);
+ SDValue SpillLoad =
+ DAG.getLoad(SpillSlot.getValueType(), getCurSDLoc(), Chain, SpillSlot,
+ MachinePointerInfo::getFixedStack(*DerivedPtrLocation),
+ false, false, false, 0);
- StatepointLowering.setRelocLocation(SD, Loc);
+ // Again, be conservative, don't emit pending loads
+ DAG.setRoot(SpillLoad.getValue(1));
- // Again, be conservative, don't emit pending loads
- DAG.setRoot(Loc.getValue(1));
- }
-
- assert(Loc.getNode());
- setValue(&CI, Loc);
+ assert(SpillLoad.getNode());
+ setValue(&CI, SpillLoad);
}