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0a9484597f
These APIs are essential for complete OSSA liveness analysis. The existing ad-hoc OSSA logic always misses some of the cases handled by these new utilities. We need to start replacing that ad-hoc logic with new utilities built on top of these APIs to define away potential latent bugs. Add FIXMEs to the inverse API: visitAdjacentBorrowsOfPhi. It should probably be redesigned in terms of these new APIs.
2417 lines
86 KiB
C++
2417 lines
86 KiB
C++
//===--- OwnershipUtils.cpp -----------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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#include "swift/SIL/OwnershipUtils.h"
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#include "swift/Basic/Defer.h"
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#include "swift/Basic/GraphNodeWorklist.h"
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#include "swift/Basic/SmallPtrSetVector.h"
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#include "swift/SIL/InstructionUtils.h"
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#include "swift/SIL/LinearLifetimeChecker.h"
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#include "swift/SIL/MemAccessUtils.h"
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#include "swift/SIL/Projection.h"
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#include "swift/SIL/PrunedLiveness.h"
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#include "swift/SIL/SILArgument.h"
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#include "swift/SIL/SILBuilder.h"
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#include "swift/SIL/SILInstruction.h"
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using namespace swift;
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bool swift::hasPointerEscape(BorrowedValue value) {
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assert(value.kind == BorrowedValueKind::BeginBorrow ||
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value.kind == BorrowedValueKind::LoadBorrow);
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GraphNodeWorklist<Operand *, 8> worklist;
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for (Operand *use : value->getUses()) {
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if (use->getOperandOwnership() != OperandOwnership::NonUse)
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worklist.insert(use);
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}
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while (Operand *op = worklist.pop()) {
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switch (op->getOperandOwnership()) {
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case OperandOwnership::NonUse:
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case OperandOwnership::TrivialUse:
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case OperandOwnership::ForwardingConsume:
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case OperandOwnership::DestroyingConsume:
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llvm_unreachable("this operand cannot handle an inner guaranteed use");
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case OperandOwnership::ForwardingUnowned:
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case OperandOwnership::PointerEscape:
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return true;
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case OperandOwnership::Borrow:
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case OperandOwnership::EndBorrow:
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case OperandOwnership::InstantaneousUse:
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case OperandOwnership::UnownedInstantaneousUse:
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case OperandOwnership::InteriorPointer:
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case OperandOwnership::BitwiseEscape:
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break;
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case OperandOwnership::Reborrow: {
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SILArgument *phi = cast<BranchInst>(op->getUser())
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->getDestBB()
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->getArgument(op->getOperandNumber());
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for (auto *use : phi->getUses()) {
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if (use->getOperandOwnership() != OperandOwnership::NonUse)
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worklist.insert(use);
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}
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break;
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}
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case OperandOwnership::GuaranteedForwarding: {
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ForwardingOperand(op).visitForwardedValues([&](SILValue result) {
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// Do not include transitive uses with 'none' ownership
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if (result->getOwnershipKind() == OwnershipKind::None)
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return true;
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for (auto *resultUse : result->getUses()) {
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if (resultUse->getOperandOwnership() != OperandOwnership::NonUse) {
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worklist.insert(resultUse);
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}
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}
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return true;
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});
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break;
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}
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}
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}
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return false;
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}
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bool swift::canOpcodeForwardInnerGuaranteedValues(SILValue value) {
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// If we have an argument from a transforming terminator, we can forward
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// guaranteed.
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if (auto *arg = dyn_cast<SILArgument>(value))
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if (auto *ti = arg->getSingleTerminator())
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if (ti->mayHaveTerminatorResult())
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return OwnershipForwardingMixin::get(ti)->preservesOwnership();
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if (auto *inst = value->getDefiningInstruction())
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if (auto *mixin = OwnershipForwardingMixin::get(inst))
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return mixin->preservesOwnership() &&
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!isa<OwnedFirstArgForwardingSingleValueInst>(inst);
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return false;
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}
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bool swift::canOpcodeForwardInnerGuaranteedValues(Operand *use) {
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if (auto *mixin = OwnershipForwardingMixin::get(use->getUser()))
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return mixin->preservesOwnership() &&
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!isa<OwnedFirstArgForwardingSingleValueInst>(use->getUser());
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return false;
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}
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bool swift::canOpcodeForwardOwnedValues(SILValue value) {
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if (auto *inst = value->getDefiningInstructionOrTerminator()) {
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if (auto *mixin = OwnershipForwardingMixin::get(inst)) {
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return mixin->preservesOwnership() &&
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!isa<GuaranteedFirstArgForwardingSingleValueInst>(inst);
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}
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}
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return false;
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}
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bool swift::canOpcodeForwardOwnedValues(Operand *use) {
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auto *user = use->getUser();
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if (auto *mixin = OwnershipForwardingMixin::get(user))
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return mixin->preservesOwnership() &&
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!isa<GuaranteedFirstArgForwardingSingleValueInst>(user);
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return false;
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}
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//===----------------------------------------------------------------------===//
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// Guaranteed Use-Point (Lifetime) Discovery
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//===----------------------------------------------------------------------===//
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// Find all use points of \p guaranteedValue within its borrow scope. All uses
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// are naturally dominated by \p guaranteedValue. If a PointerEscape is found,
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// then no assumption can be made about \p guaranteedValue's lifetime. Therefore
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// the use points are incomplete and this returns false.
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//
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// Accumulate results in \p usePoints, ignoring existing elements.
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//
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// Skip over nested borrow scopes. Their scope-ending instructions are their use
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// points. Transitively find all nested scope-ending instructions by looking
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// through nested reborrows. Nested reborrows are not use points.
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//
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// FIXME: handle inner reborrows, which aren't dominated by
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// guaranteedValue. Audit all users to handle reborrows.
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bool swift::findInnerTransitiveGuaranteedUses(
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SILValue guaranteedValue, SmallVectorImpl<Operand *> *usePoints) {
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bool foundPointerEscape = false;
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auto leafUse = [&](Operand *use) {
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if (usePoints && use->getOperandOwnership() != OperandOwnership::NonUse) {
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usePoints->push_back(use);
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}
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return true;
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};
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// Push the value's immediate uses.
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//
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// TODO: The worklist can be a simple vector without any a membership check if
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// destructures are changed to be represented as reborrows. Currently a
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// destructure forwards multiple results! This means that the worklist could
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// grow exponentially without the membership check. It's fine to do this
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// membership check locally in this function (within a borrow scope) because
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// it isn't needed for the immediate uses, only the transitive uses.
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GraphNodeWorklist<Operand *, 8> worklist;
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for (Operand *use : guaranteedValue->getUses()) {
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if (use->getOperandOwnership() != OperandOwnership::NonUse)
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worklist.insert(use);
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}
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// --- Transitively follow forwarded uses and look for escapes.
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// usePoints grows in this loop.
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while (Operand *use = worklist.pop()) {
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switch (use->getOperandOwnership()) {
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case OperandOwnership::NonUse:
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case OperandOwnership::TrivialUse:
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case OperandOwnership::ForwardingConsume:
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case OperandOwnership::DestroyingConsume:
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llvm_unreachable("this operand cannot handle an inner guaranteed use");
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case OperandOwnership::ForwardingUnowned:
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case OperandOwnership::PointerEscape:
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leafUse(use);
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foundPointerEscape = true;
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break;
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case OperandOwnership::InstantaneousUse:
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case OperandOwnership::UnownedInstantaneousUse:
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case OperandOwnership::BitwiseEscape:
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// Reborrow only happens when this is called on a value that creates a
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// borrow scope.
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case OperandOwnership::Reborrow:
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// EndBorrow either happens when this is called on a value that creates a
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// borrow scope, or when it is pushed as a use when processing a nested
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// borrow.
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case OperandOwnership::EndBorrow:
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leafUse(use);
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break;
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case OperandOwnership::InteriorPointer:
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#if 0 // FIXME!!! Enable in a following commit that fixes RAUW
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// If our base guaranteed value does not have any consuming uses
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// (consider function arguments), we need to be sure to include interior
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// pointer operands since we may not get a use from a end_scope
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// instruction.
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if (InteriorPointerOperand(use).findTransitiveUses(usePoints)
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!= AddressUseKind::NonEscaping) {
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foundPointerEscape = true;
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}
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#endif
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leafUse(use);
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foundPointerEscape = true;
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break;
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case OperandOwnership::GuaranteedForwarding: {
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bool nonLeaf = false;
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ForwardingOperand(use).visitForwardedValues([&](SILValue result) {
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// Do not include transitive uses with 'none' ownership
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if (result->getOwnershipKind() == OwnershipKind::None)
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return true;
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if (auto *phi = SILArgument::asPhi(result)) {
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leafUse(use);
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foundPointerEscape = true;
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return true;
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}
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for (auto *resultUse : result->getUses()) {
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if (resultUse->getOperandOwnership() != OperandOwnership::NonUse) {
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nonLeaf = true;
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worklist.insert(resultUse);
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}
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}
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return true;
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});
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// e.g. A dead forwarded value, e.g. a switch_enum with only trivial uses,
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// must itself be a leaf use.
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if (!nonLeaf) {
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leafUse(use);
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}
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break;
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}
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case OperandOwnership::Borrow:
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// FIXME: Use visitExtendedScopeEndingUses and audit all clients to handle
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// reborrows.
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//
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// FIXME: visit[Extended]ScopeEndingUses can't return false here once dead
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// borrows are disallowed.
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if (!BorrowingOperand(use).visitScopeEndingUses([&](Operand *endUse) {
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if (endUse->getOperandOwnership() == OperandOwnership::Reborrow) {
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foundPointerEscape = true;
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}
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leafUse(endUse);
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return true;
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})) {
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// Special case for dead borrows. This is dangerous because clients
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// don't expect a begin_borrow to be in the use list.
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leafUse(use);
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}
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break;
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}
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}
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return !foundPointerEscape;
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}
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/// Find all uses in the extended lifetime (i.e. including copies) of a simple
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/// (i.e. not reborrowed) borrow scope and its transitive uses.
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bool swift::findExtendedUsesOfSimpleBorrowedValue(
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BorrowedValue borrowedValue, SmallVectorImpl<Operand *> *usePoints) {
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auto recordUse = [&](Operand *use) {
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if (usePoints && use->getOperandOwnership() != OperandOwnership::NonUse) {
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usePoints->push_back(use);
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}
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};
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// Push the value's immediate uses.
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//
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// TODO: The worklist can be a simple vector without any a membership check if
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// destructures are changed to be represented as reborrows. Currently a
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// destructure forwards multiple results! This means that the worklist could
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// grow exponentially without the membership check. It's fine to do this
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// membership check locally in this function (within a borrow scope) because
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// it isn't needed for the immediate uses, only the transitive uses.
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GraphNodeWorklist<Operand *, 8> worklist;
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auto addUsesToWorklist = [&worklist](SILValue value) {
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for (Operand *use : value->getUses()) {
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if (use->getOperandOwnership() != OperandOwnership::NonUse)
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worklist.insert(use);
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}
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};
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addUsesToWorklist(borrowedValue.value);
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// --- Transitively follow forwarded uses and look for escapes.
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// usePoints grows in this loop.
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while (Operand *use = worklist.pop()) {
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if (auto *cvi = dyn_cast<CopyValueInst>(use->getUser())) {
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addUsesToWorklist(cvi);
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}
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switch (use->getOperandOwnership()) {
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case OperandOwnership::NonUse:
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break;
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case OperandOwnership::TrivialUse:
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case OperandOwnership::ForwardingConsume:
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case OperandOwnership::DestroyingConsume:
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recordUse(use);
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break;
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case OperandOwnership::ForwardingUnowned:
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case OperandOwnership::PointerEscape:
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case OperandOwnership::Reborrow:
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return false;
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case OperandOwnership::InstantaneousUse:
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case OperandOwnership::UnownedInstantaneousUse:
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case OperandOwnership::BitwiseEscape:
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// EndBorrow either happens when this is called on a value that creates a
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// borrow scope, or when it is pushed as a use when processing a nested
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// borrow.
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case OperandOwnership::EndBorrow:
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recordUse(use);
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break;
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case OperandOwnership::InteriorPointer:
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if (InteriorPointerOperandKind::get(use) ==
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InteriorPointerOperandKind::Invalid)
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return false;
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// If our base guaranteed value does not have any consuming uses (consider
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// function arguments), we need to be sure to include interior pointer
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// operands since we may not get a use from a end_scope instruction.
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if (InteriorPointerOperand(use).findTransitiveUses(usePoints) !=
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AddressUseKind::NonEscaping) {
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return false;
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}
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recordUse(use);
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break;
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case OperandOwnership::GuaranteedForwarding: {
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ForwardingOperand(use).visitForwardedValues([&](SILValue result) {
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// Do not include transitive uses with 'none' ownership
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if (result->getOwnershipKind() == OwnershipKind::None)
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return true;
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for (auto *resultUse : result->getUses()) {
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if (resultUse->getOperandOwnership() != OperandOwnership::NonUse) {
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worklist.insert(resultUse);
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}
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}
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return true;
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});
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recordUse(use);
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break;
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}
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case OperandOwnership::Borrow:
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// FIXME: visitExtendedScopeEndingUses can't return false here once dead
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// borrows are disallowed.
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if (!BorrowingOperand(use).visitExtendedScopeEndingUses(
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[&](Operand *endUse) {
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recordUse(endUse);
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return true;
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})) {
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// Special case for dead borrows. This is dangerous because clients
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// don't expect a begin_borrow to be in the use list.
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recordUse(use);
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}
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break;
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}
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}
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return true;
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}
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// TODO: refactor this with SSAPrunedLiveness::computeLiveness.
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bool swift::findUsesOfSimpleValue(SILValue value,
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SmallVectorImpl<Operand *> *usePoints) {
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for (auto *use : value->getUses()) {
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switch (use->getOperandOwnership()) {
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case OperandOwnership::PointerEscape:
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return false;
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case OperandOwnership::Borrow:
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if (!BorrowingOperand(use).visitScopeEndingUses([&](Operand *end) {
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if (end->getOperandOwnership() == OperandOwnership::Reborrow) {
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return false;
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}
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usePoints->push_back(end);
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return true;
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})) {
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return false;
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}
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break;
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default:
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break;
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}
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usePoints->push_back(use);
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}
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return true;
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}
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bool swift::visitGuaranteedForwardingPhisForSSAValue(
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SILValue value, function_ref<bool(Operand *)> visitor) {
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assert(isa<BeginBorrowInst>(value) || isa<LoadBorrowInst>(value) ||
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(isa<SILPhiArgument>(value) &&
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value->getOwnershipKind() == OwnershipKind::Guaranteed));
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// guaranteedForwardingOps is a collection of all transitive
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// GuaranteedForwarding uses of \p value. It is a set, to avoid repeated
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// processing of structs and tuples which are GuaranteedForwarding.
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SmallSetVector<Operand *, 4> guaranteedForwardingOps;
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// Collect first-level GuaranteedForwarding uses, and call the visitor on any
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// GuaranteedForwardingPhi uses.
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for (auto *use : value->getUses()) {
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if (use->getOperandOwnership() == OperandOwnership::GuaranteedForwarding) {
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if (PhiOperand(use)) {
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if (!visitor(use)) {
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return false;
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}
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}
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guaranteedForwardingOps.insert(use);
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}
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}
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// Transitively, collect GuaranteedForwarding uses.
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for (unsigned i = 0; i < guaranteedForwardingOps.size(); i++) {
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for (auto val : guaranteedForwardingOps[i]->getUser()->getResults()) {
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for (auto *valUse : val->getUses()) {
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if (valUse->getOperandOwnership() ==
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OperandOwnership::GuaranteedForwarding) {
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if (PhiOperand(valUse)) {
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if (!visitor(valUse)) {
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return false;
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}
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}
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guaranteedForwardingOps.insert(valUse);
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}
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}
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}
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}
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return true;
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}
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// Find all use points of \p guaranteedValue within its borrow scope. All use
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// points will be dominated by \p guaranteedValue.
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//
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// Record (non-nested) reborrows as uses.
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//
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// BorrowedValues (which introduce a borrow scope) are fundamentally different
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// than "inner" guaranteed values. Their only use points are their scope-ending
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// uses. There is no need to transitively process uses. However, unlike inner
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// guaranteed values, they can have reborrows. To transitively process
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// reborrows, use findExtendedTransitiveBorrowedUses.
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bool swift::findTransitiveGuaranteedUses(
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SILValue guaranteedValue, SmallVectorImpl<Operand *> &usePoints,
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function_ref<void(Operand *)> visitReborrow) {
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// Handle local borrow introducers without following uses.
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// SILFunctionArguments are *not* borrow introducers in this context--we're
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// trying to find lifetime of values within a function.
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if (auto borrowedValue = BorrowedValue(guaranteedValue)) {
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if (borrowedValue.isLocalScope()) {
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borrowedValue.visitLocalScopeEndingUses([&](Operand *scopeEnd) {
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// Initially push the reborrow as a use point. visitReborrow may pop it
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// if it only wants to compute the extended lifetime's use points.
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usePoints.push_back(scopeEnd);
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if (scopeEnd->getOperandOwnership() == OperandOwnership::Reborrow)
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visitReborrow(scopeEnd);
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return true;
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});
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}
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return true;
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}
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return findInnerTransitiveGuaranteedUses(guaranteedValue, &usePoints);
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}
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// Find all use points of \p guaranteedValue within its borrow scope. If the
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// guaranteed value introduces a borrow scope, then this includes the extended
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// borrow scope by following reborrows.
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bool swift::
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findExtendedTransitiveGuaranteedUses(SILValue guaranteedValue,
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SmallVectorImpl<Operand *> &usePoints) {
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// Multiple paths may reach the same reborrows, and reborrow may even be
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// recursive, so the working set requires a membership check.
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SmallPtrSetVector<SILValue, 4> reborrows;
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|
auto visitReborrow = [&](Operand *reborrow) {
|
|
// Pop the reborrow. It should not appear in the use points of the
|
|
// extend lifetime.
|
|
assert(reborrow == usePoints.back());
|
|
usePoints.pop_back();
|
|
auto borrowedPhi =
|
|
BorrowingOperand(reborrow).getBorrowIntroducingUserResult();
|
|
reborrows.insert(borrowedPhi.value);
|
|
};
|
|
if (!findTransitiveGuaranteedUses(guaranteedValue, usePoints, visitReborrow))
|
|
return false;
|
|
|
|
// For guaranteed values that do not introduce a borrow scope, reborrows will
|
|
// be empty at this point.
|
|
for (unsigned idx = 0; idx < reborrows.size(); ++idx) {
|
|
bool result =
|
|
findTransitiveGuaranteedUses(reborrows[idx], usePoints, visitReborrow);
|
|
// It is impossible to find a Pointer escape while traversing reborrows.
|
|
assert(result && "visiting reborrows always succeeds");
|
|
(void)result;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Borrowing Operand
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
void BorrowingOperandKind::print(llvm::raw_ostream &os) const {
|
|
switch (value) {
|
|
case Kind::Invalid:
|
|
llvm_unreachable("Using an unreachable?!");
|
|
case Kind::BeginBorrow:
|
|
os << "BeginBorrow";
|
|
return;
|
|
case Kind::BeginApply:
|
|
os << "BeginApply";
|
|
return;
|
|
case Kind::Branch:
|
|
os << "Branch";
|
|
return;
|
|
case Kind::Apply:
|
|
os << "Apply";
|
|
return;
|
|
case Kind::TryApply:
|
|
os << "TryApply";
|
|
return;
|
|
case Kind::Yield:
|
|
os << "Yield";
|
|
return;
|
|
}
|
|
llvm_unreachable("Covered switch isn't covered?!");
|
|
}
|
|
|
|
llvm::raw_ostream &swift::operator<<(llvm::raw_ostream &os,
|
|
BorrowingOperandKind kind) {
|
|
kind.print(os);
|
|
return os;
|
|
}
|
|
|
|
void BorrowingOperand::print(llvm::raw_ostream &os) const {
|
|
os << "BorrowScopeOperand:\n"
|
|
"Kind: " << kind << "\n"
|
|
"Value: " << op->get()
|
|
<< "User: " << *op->getUser();
|
|
}
|
|
|
|
llvm::raw_ostream &swift::operator<<(llvm::raw_ostream &os,
|
|
const BorrowingOperand &operand) {
|
|
operand.print(os);
|
|
return os;
|
|
}
|
|
|
|
bool BorrowingOperand::hasEmptyRequiredEndingUses() const {
|
|
switch (kind) {
|
|
case BorrowingOperandKind::Invalid:
|
|
llvm_unreachable("Using invalid case");
|
|
case BorrowingOperandKind::BeginBorrow:
|
|
case BorrowingOperandKind::BeginApply: {
|
|
return op->getUser()->hasUsesOfAnyResult();
|
|
}
|
|
case BorrowingOperandKind::Branch: {
|
|
auto *br = cast<BranchInst>(op->getUser());
|
|
return br->getArgForOperand(op)->use_empty();
|
|
}
|
|
// These are instantaneous borrow scopes so there aren't any special end
|
|
// scope instructions.
|
|
case BorrowingOperandKind::Apply:
|
|
case BorrowingOperandKind::TryApply:
|
|
case BorrowingOperandKind::Yield:
|
|
return false;
|
|
}
|
|
llvm_unreachable("Covered switch isn't covered");
|
|
}
|
|
|
|
bool BorrowingOperand::visitScopeEndingUses(
|
|
function_ref<bool(Operand *)> func) const {
|
|
switch (kind) {
|
|
case BorrowingOperandKind::Invalid:
|
|
llvm_unreachable("Using invalid case");
|
|
case BorrowingOperandKind::BeginBorrow: {
|
|
bool deadBorrow = true;
|
|
for (auto *use : cast<BeginBorrowInst>(op->getUser())->getUses()) {
|
|
if (use->isLifetimeEnding()) {
|
|
deadBorrow = false;
|
|
if (!func(use))
|
|
return false;
|
|
}
|
|
}
|
|
// FIXME: special case for dead borrows. This is dangerous because clients
|
|
// only expect visitScopeEndingUses to return false if the visitor returned
|
|
// false.
|
|
return !deadBorrow;
|
|
}
|
|
case BorrowingOperandKind::BeginApply: {
|
|
bool deadApply = true;
|
|
auto *user = cast<BeginApplyInst>(op->getUser());
|
|
for (auto *use : user->getTokenResult()->getUses()) {
|
|
deadApply = false;
|
|
if (!func(use))
|
|
return false;
|
|
}
|
|
return !deadApply;
|
|
}
|
|
// These are instantaneous borrow scopes so there aren't any special end
|
|
// scope instructions.
|
|
case BorrowingOperandKind::Apply:
|
|
case BorrowingOperandKind::TryApply:
|
|
case BorrowingOperandKind::Yield:
|
|
return true;
|
|
case BorrowingOperandKind::Branch: {
|
|
bool deadBranch = true;
|
|
auto *br = cast<BranchInst>(op->getUser());
|
|
for (auto *use : br->getArgForOperand(op)->getUses()) {
|
|
if (use->isLifetimeEnding()) {
|
|
deadBranch = false;
|
|
if (!func(use))
|
|
return false;
|
|
}
|
|
}
|
|
return !deadBranch;
|
|
}
|
|
}
|
|
llvm_unreachable("Covered switch isn't covered");
|
|
}
|
|
|
|
bool BorrowingOperand::visitExtendedScopeEndingUses(
|
|
function_ref<bool(Operand *)> visitor) const {
|
|
|
|
if (hasBorrowIntroducingUser()) {
|
|
return visitBorrowIntroducingUserResults(
|
|
[visitor](BorrowedValue borrowedValue) {
|
|
return borrowedValue.visitExtendedScopeEndingUses(visitor);
|
|
});
|
|
}
|
|
return visitScopeEndingUses(visitor);
|
|
}
|
|
|
|
bool BorrowingOperand::visitBorrowIntroducingUserResults(
|
|
function_ref<bool(BorrowedValue)> visitor) const {
|
|
switch (kind) {
|
|
case BorrowingOperandKind::Invalid:
|
|
llvm_unreachable("Using invalid case");
|
|
case BorrowingOperandKind::Apply:
|
|
case BorrowingOperandKind::TryApply:
|
|
case BorrowingOperandKind::BeginApply:
|
|
case BorrowingOperandKind::Yield:
|
|
llvm_unreachable("Never has borrow introducer results!");
|
|
case BorrowingOperandKind::BeginBorrow: {
|
|
auto value = BorrowedValue(cast<BeginBorrowInst>(op->getUser()));
|
|
assert(value);
|
|
return visitor(value);
|
|
}
|
|
case BorrowingOperandKind::Branch: {
|
|
auto *bi = cast<BranchInst>(op->getUser());
|
|
auto value = BorrowedValue(
|
|
bi->getDestBB()->getArgument(op->getOperandNumber()));
|
|
assert(value && "guaranteed-to-unowned conversion not allowed on branches");
|
|
return visitor(value);
|
|
}
|
|
}
|
|
llvm_unreachable("Covered switch isn't covered?!");
|
|
}
|
|
|
|
BorrowedValue BorrowingOperand::getBorrowIntroducingUserResult() {
|
|
switch (kind) {
|
|
case BorrowingOperandKind::Invalid:
|
|
case BorrowingOperandKind::Apply:
|
|
case BorrowingOperandKind::TryApply:
|
|
case BorrowingOperandKind::BeginApply:
|
|
case BorrowingOperandKind::Yield:
|
|
return BorrowedValue();
|
|
|
|
case BorrowingOperandKind::BeginBorrow:
|
|
return BorrowedValue(cast<BeginBorrowInst>(op->getUser()));
|
|
|
|
case BorrowingOperandKind::Branch: {
|
|
auto *bi = cast<BranchInst>(op->getUser());
|
|
return BorrowedValue(bi->getDestBB()->getArgument(op->getOperandNumber()));
|
|
}
|
|
}
|
|
llvm_unreachable("covered switch");
|
|
}
|
|
|
|
void BorrowingOperand::getImplicitUses(
|
|
SmallVectorImpl<Operand *> &foundUses) const {
|
|
// FIXME: this visitScopeEndingUses should never return false once dead
|
|
// borrows are disallowed.
|
|
if (!visitScopeEndingUses([&](Operand *endOp) {
|
|
foundUses.push_back(endOp);
|
|
return true;
|
|
})) {
|
|
// Special-case for dead borrows.
|
|
foundUses.push_back(op);
|
|
}
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Borrow Introducers
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
void BorrowedValueKind::print(llvm::raw_ostream &os) const {
|
|
switch (value) {
|
|
case BorrowedValueKind::Invalid:
|
|
llvm_unreachable("Using invalid case?!");
|
|
case BorrowedValueKind::SILFunctionArgument:
|
|
os << "SILFunctionArgument";
|
|
return;
|
|
case BorrowedValueKind::BeginBorrow:
|
|
os << "BeginBorrowInst";
|
|
return;
|
|
case BorrowedValueKind::LoadBorrow:
|
|
os << "LoadBorrowInst";
|
|
return;
|
|
case BorrowedValueKind::Phi:
|
|
os << "Phi";
|
|
return;
|
|
}
|
|
llvm_unreachable("Covered switch isn't covered?!");
|
|
}
|
|
|
|
void BorrowedValue::print(llvm::raw_ostream &os) const {
|
|
os << "BorrowScopeIntroducingValue:\n"
|
|
"Kind: " << kind << "\n"
|
|
"Value: " << value;
|
|
}
|
|
|
|
void BorrowedValue::getLocalScopeEndingInstructions(
|
|
SmallVectorImpl<SILInstruction *> &scopeEndingInsts) const {
|
|
assert(isLocalScope() && "Should only call this given a local scope");
|
|
|
|
switch (kind) {
|
|
case BorrowedValueKind::Invalid:
|
|
llvm_unreachable("Using invalid case?!");
|
|
case BorrowedValueKind::SILFunctionArgument:
|
|
llvm_unreachable("Should only call this with a local scope");
|
|
case BorrowedValueKind::BeginBorrow:
|
|
case BorrowedValueKind::LoadBorrow:
|
|
case BorrowedValueKind::Phi:
|
|
for (auto *use : value->getUses()) {
|
|
if (use->isLifetimeEnding()) {
|
|
scopeEndingInsts.push_back(use->getUser());
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
llvm_unreachable("Covered switch isn't covered?!");
|
|
}
|
|
|
|
// Note: BorrowedLifetimeExtender assumes no intermediate values between a
|
|
// borrow introducer and its reborrow. The borrowed value must be an operand of
|
|
// the reborrow.
|
|
bool BorrowedValue::visitLocalScopeEndingUses(
|
|
function_ref<bool(Operand *)> visitor) const {
|
|
assert(isLocalScope() && "Should only call this given a local scope");
|
|
switch (kind) {
|
|
case BorrowedValueKind::Invalid:
|
|
llvm_unreachable("Using invalid case?!");
|
|
case BorrowedValueKind::SILFunctionArgument:
|
|
llvm_unreachable("Should only call this with a local scope");
|
|
case BorrowedValueKind::LoadBorrow:
|
|
case BorrowedValueKind::BeginBorrow:
|
|
case BorrowedValueKind::Phi:
|
|
for (auto *use : value->getUses()) {
|
|
if (use->isLifetimeEnding()) {
|
|
if (!visitor(use))
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
llvm_unreachable("Covered switch isn't covered?!");
|
|
}
|
|
|
|
llvm::raw_ostream &swift::operator<<(llvm::raw_ostream &os,
|
|
BorrowedValueKind kind) {
|
|
kind.print(os);
|
|
return os;
|
|
}
|
|
|
|
llvm::raw_ostream &swift::operator<<(llvm::raw_ostream &os,
|
|
const BorrowedValue &value) {
|
|
value.print(os);
|
|
return os;
|
|
}
|
|
|
|
/// Add this scopes live blocks into the PrunedLiveness result.
|
|
void BorrowedValue::
|
|
computeTransitiveLiveness(MultiDefPrunedLiveness &liveness) const {
|
|
liveness.initializeDef(value);
|
|
visitTransitiveLifetimeEndingUses([&](Operand *endOp) {
|
|
if (endOp->getOperandOwnership() == OperandOwnership::EndBorrow) {
|
|
liveness.updateForUse(endOp->getUser(), /*lifetimeEnding*/ true);
|
|
return true;
|
|
}
|
|
assert(endOp->getOperandOwnership() == OperandOwnership::Reborrow);
|
|
PhiOperand phiOper(endOp);
|
|
liveness.initializeDef(phiOper.getValue());
|
|
liveness.updateForUse(endOp->getUser(), /*lifetimeEnding*/ false);
|
|
return true;
|
|
});
|
|
}
|
|
|
|
bool BorrowedValue::areUsesWithinExtendedScope(
|
|
ArrayRef<Operand *> uses, DeadEndBlocks *deadEndBlocks) const {
|
|
// First make sure that we actually have a local scope. If we have a non-local
|
|
// scope, then we have something (like a SILFunctionArgument) where a larger
|
|
// semantic construct (in the case of SILFunctionArgument, the function
|
|
// itself) acts as the scope. So we already know that our passed in
|
|
// instructions must be in the same scope.
|
|
if (!isLocalScope())
|
|
return true;
|
|
|
|
// Compute the local scope's liveness.
|
|
MultiDefPrunedLiveness liveness(value->getFunction());
|
|
computeTransitiveLiveness(liveness);
|
|
return liveness.areUsesWithinBoundary(uses, deadEndBlocks);
|
|
}
|
|
|
|
// The visitor \p func is only called on final scope-ending uses, not reborrows.
|
|
bool BorrowedValue::visitExtendedScopeEndingUses(
|
|
function_ref<bool(Operand *)> visitor) const {
|
|
assert(isLocalScope());
|
|
|
|
SmallPtrSetVector<SILValue, 4> reborrows;
|
|
|
|
auto visitEnd = [&](Operand *scopeEndingUse) {
|
|
if (scopeEndingUse->getOperandOwnership() == OperandOwnership::Reborrow) {
|
|
BorrowingOperand(scopeEndingUse).visitBorrowIntroducingUserResults(
|
|
[&](BorrowedValue borrowedValue) {
|
|
reborrows.insert(borrowedValue.value);
|
|
return true;
|
|
});
|
|
return true;
|
|
}
|
|
return visitor(scopeEndingUse);
|
|
};
|
|
|
|
if (!visitLocalScopeEndingUses(visitEnd))
|
|
return false;
|
|
|
|
// reborrows grows in this loop.
|
|
for (unsigned idx = 0; idx < reborrows.size(); ++idx) {
|
|
if (!BorrowedValue(reborrows[idx]).visitLocalScopeEndingUses(visitEnd))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
bool BorrowedValue::visitTransitiveLifetimeEndingUses(
|
|
function_ref<bool(Operand *)> visitor) const {
|
|
assert(isLocalScope());
|
|
|
|
SmallPtrSetVector<SILValue, 4> reborrows;
|
|
|
|
auto visitEnd = [&](Operand *scopeEndingUse) {
|
|
if (scopeEndingUse->getOperandOwnership() == OperandOwnership::Reborrow) {
|
|
BorrowingOperand(scopeEndingUse)
|
|
.visitBorrowIntroducingUserResults([&](BorrowedValue borrowedValue) {
|
|
reborrows.insert(borrowedValue.value);
|
|
return true;
|
|
});
|
|
// visitor on the reborrow
|
|
return visitor(scopeEndingUse);
|
|
}
|
|
// visitor on the end_borrow
|
|
return visitor(scopeEndingUse);
|
|
};
|
|
|
|
if (!visitLocalScopeEndingUses(visitEnd))
|
|
return false;
|
|
|
|
// reborrows grows in this loop.
|
|
for (unsigned idx = 0; idx < reborrows.size(); ++idx) {
|
|
if (!BorrowedValue(reborrows[idx]).visitLocalScopeEndingUses(visitEnd))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
bool BorrowedValue::visitInteriorPointerOperandHelper(
|
|
function_ref<void(InteriorPointerOperand)> func,
|
|
BorrowedValue::InteriorPointerOperandVisitorKind kind) const {
|
|
using Kind = BorrowedValue::InteriorPointerOperandVisitorKind;
|
|
|
|
SmallVector<Operand *, 32> worklist(value->getUses());
|
|
while (!worklist.empty()) {
|
|
auto *op = worklist.pop_back_val();
|
|
|
|
if (auto interiorPointer = InteriorPointerOperand(op)) {
|
|
func(interiorPointer);
|
|
continue;
|
|
}
|
|
|
|
if (auto borrowingOperand = BorrowingOperand(op)) {
|
|
switch (kind) {
|
|
case Kind::NoNestedNoReborrows:
|
|
// We do not look through nested things and or reborrows, so just
|
|
// continue.
|
|
continue;
|
|
case Kind::YesNestedNoReborrows:
|
|
// We only look through nested borrowing operands, we never look through
|
|
// reborrows though.
|
|
if (borrowingOperand.isReborrow())
|
|
continue;
|
|
break;
|
|
case Kind::YesNestedYesReborrows:
|
|
// Look through everything!
|
|
break;
|
|
}
|
|
|
|
borrowingOperand.visitBorrowIntroducingUserResults([&](auto bv) {
|
|
for (auto *use : bv->getUses()) {
|
|
if (auto intPtrOperand = InteriorPointerOperand(use)) {
|
|
func(intPtrOperand);
|
|
continue;
|
|
}
|
|
worklist.push_back(use);
|
|
}
|
|
return true;
|
|
});
|
|
continue;
|
|
}
|
|
|
|
auto *user = op->getUser();
|
|
if (isa<DebugValueInst>(user) || isa<SuperMethodInst>(user) ||
|
|
isa<ClassMethodInst>(user) || isa<CopyValueInst>(user) ||
|
|
isa<EndBorrowInst>(user) || isa<ApplyInst>(user) ||
|
|
isa<StoreInst>(user) || isa<PartialApplyInst>(user) ||
|
|
isa<UnmanagedRetainValueInst>(user) ||
|
|
isa<UnmanagedReleaseValueInst>(user) ||
|
|
isa<UnmanagedAutoreleaseValueInst>(user)) {
|
|
continue;
|
|
}
|
|
|
|
// These are interior pointers that have not had support yet added for them.
|
|
if (isa<ProjectExistentialBoxInst>(user)) {
|
|
continue;
|
|
}
|
|
|
|
// Look through object.
|
|
if (auto *svi = dyn_cast<SingleValueInstruction>(user)) {
|
|
if (Projection::isObjectProjection(svi)) {
|
|
for (SILValue result : user->getResults()) {
|
|
llvm::copy(result->getUses(), std::back_inserter(worklist));
|
|
}
|
|
continue;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// FIXME: This does not yet assume complete lifetimes. Therefore, it currently
|
|
// recursively looks through scoped uses, such as load_borrow. We should
|
|
// separate the logic for lifetime completion from the logic that can assume
|
|
// complete lifetimes.
|
|
AddressUseKind
|
|
swift::findTransitiveUsesForAddress(SILValue projectedAddress,
|
|
SmallVectorImpl<Operand *> *foundUses,
|
|
std::function<void(Operand *)> *onError) {
|
|
// If the projectedAddress is dead, it is itself a leaf use. Since we don't
|
|
// have an operand for it, simply bail. Dead projectedAddress is unexpected.
|
|
//
|
|
// TODO: store_borrow is currently an InteriorPointer with no uses, so we end
|
|
// up bailing. It should be in a dependence scope instead. It's not clear why
|
|
// it produces an address at all.
|
|
if (projectedAddress->use_empty())
|
|
return AddressUseKind::PointerEscape;
|
|
|
|
SmallVector<Operand *, 8> worklist(projectedAddress->getUses());
|
|
|
|
AddressUseKind result = AddressUseKind::NonEscaping;
|
|
|
|
auto leafUse = [foundUses](Operand *use) {
|
|
if (foundUses)
|
|
foundUses->push_back(use);
|
|
};
|
|
auto transitiveResultUses = [&](Operand *use) {
|
|
auto *svi = cast<SingleValueInstruction>(use->getUser());
|
|
if (svi->use_empty()) {
|
|
leafUse(use);
|
|
} else {
|
|
worklist.append(svi->use_begin(), svi->use_end());
|
|
}
|
|
};
|
|
|
|
while (!worklist.empty()) {
|
|
auto *op = worklist.pop_back_val();
|
|
|
|
// Skip type dependent operands.
|
|
if (op->isTypeDependent())
|
|
continue;
|
|
|
|
// Then update the worklist with new things to find if we recognize this
|
|
// inst and then continue. If we fail, we emit an error at the bottom of the
|
|
// loop that we didn't recognize the user.
|
|
auto *user = op->getUser();
|
|
|
|
// TODO: Partial apply should be NonEscaping, but then we need to consider
|
|
// the apply to be a use point.
|
|
if (isa<PartialApplyInst>(user) || isa<AddressToPointerInst>(user)) {
|
|
result = meet(result, AddressUseKind::PointerEscape);
|
|
continue;
|
|
}
|
|
// First, eliminate "end point uses" that we just need to check liveness at
|
|
// and do not need to check transitive uses of.
|
|
if (isa<LoadInst>(user) || isa<CopyAddrInst>(user) ||
|
|
isa<MarkUnresolvedMoveAddrInst>(user) || isIncidentalUse(user) ||
|
|
isa<StoreInst>(user) || isa<DestroyAddrInst>(user) ||
|
|
isa<AssignInst>(user) || isa<YieldInst>(user) ||
|
|
isa<LoadUnownedInst>(user) || isa<StoreUnownedInst>(user) ||
|
|
isa<EndApplyInst>(user) || isa<LoadWeakInst>(user) ||
|
|
isa<StoreWeakInst>(user) || isa<AssignByWrapperInst>(user) ||
|
|
isa<BeginUnpairedAccessInst>(user) ||
|
|
isa<EndUnpairedAccessInst>(user) || isa<WitnessMethodInst>(user) ||
|
|
isa<SwitchEnumAddrInst>(user) || isa<CheckedCastAddrBranchInst>(user) ||
|
|
isa<SelectEnumAddrInst>(user) || isa<InjectEnumAddrInst>(user) ||
|
|
isa<IsUniqueInst>(user) || isa<ValueMetatypeInst>(user) ||
|
|
isa<DebugValueInst>(user) || isa<EndBorrowInst>(user)) {
|
|
leafUse(op);
|
|
continue;
|
|
}
|
|
|
|
if (isa<UnconditionalCheckedCastAddrInst>(user)
|
|
|| isa<MarkFunctionEscapeInst>(user)) {
|
|
assert(!user->hasResults());
|
|
continue;
|
|
}
|
|
|
|
// Then handle users that we need to look at transitive uses of.
|
|
if (Projection::isAddressProjection(user) ||
|
|
isa<ProjectBlockStorageInst>(user) ||
|
|
isa<OpenExistentialAddrInst>(user) ||
|
|
isa<InitExistentialAddrInst>(user) || isa<InitEnumDataAddrInst>(user) ||
|
|
isa<BeginAccessInst>(user) || isa<TailAddrInst>(user) ||
|
|
isa<IndexAddrInst>(user) || isa<StoreBorrowInst>(user) ||
|
|
isa<UncheckedAddrCastInst>(user) || isa<MarkMustCheckInst>(user)) {
|
|
transitiveResultUses(op);
|
|
continue;
|
|
}
|
|
|
|
if (auto *builtin = dyn_cast<BuiltinInst>(user)) {
|
|
if (auto kind = builtin->getBuiltinKind()) {
|
|
if (*kind == BuiltinValueKind::TSanInoutAccess) {
|
|
leafUse(op);
|
|
continue;
|
|
}
|
|
}
|
|
}
|
|
|
|
// If we have a load_borrow, add it's end scope to the liveness requirement.
|
|
if (auto *lbi = dyn_cast<LoadBorrowInst>(user)) {
|
|
// FIXME: if we can assume complete lifetimes, then this should be
|
|
// as simple as:
|
|
// for (Operand *use : lbi->getUses()) {
|
|
// if (use->endsLocalBorrowScope()) {
|
|
if (!findInnerTransitiveGuaranteedUses(lbi, foundUses)) {
|
|
result = meet(result, AddressUseKind::PointerEscape);
|
|
}
|
|
continue;
|
|
}
|
|
|
|
// TODO: Merge this into the full apply site code below.
|
|
if (auto *beginApply = dyn_cast<BeginApplyInst>(user)) {
|
|
if (foundUses) {
|
|
// TODO: the empty check should not be needed when dead begin_apply is
|
|
// disallowed.
|
|
if (beginApply->getTokenResult()->use_empty()) {
|
|
leafUse(op);
|
|
} else {
|
|
llvm::copy(beginApply->getTokenResult()->getUses(),
|
|
std::back_inserter(*foundUses));
|
|
}
|
|
}
|
|
continue;
|
|
}
|
|
|
|
if (auto fas = FullApplySite::isa(user)) {
|
|
leafUse(op);
|
|
continue;
|
|
}
|
|
|
|
if (auto *mdi = dyn_cast<MarkDependenceInst>(user)) {
|
|
// If this is the base, just treat it as a liveness use.
|
|
if (op->get() == mdi->getBase()) {
|
|
leafUse(op);
|
|
continue;
|
|
}
|
|
|
|
// If we are the value use, look through it.
|
|
transitiveResultUses(op);
|
|
continue;
|
|
}
|
|
|
|
// We were unable to recognize this user, so return true that we failed.
|
|
if (onError) {
|
|
(*onError)(op);
|
|
}
|
|
result = meet(result, AddressUseKind::Unknown);
|
|
}
|
|
return result;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// AddressOwnership
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
bool AddressOwnership::areUsesWithinLifetime(
|
|
ArrayRef<Operand *> uses, DeadEndBlocks &deadEndBlocks) const {
|
|
if (!base.hasLocalOwnershipLifetime())
|
|
return true;
|
|
|
|
SILValue root = base.getOwnershipReferenceRoot();
|
|
BorrowedValue borrow(root);
|
|
if (borrow)
|
|
return borrow.areUsesWithinExtendedScope(uses, &deadEndBlocks);
|
|
|
|
// --- A reference with no borrow scope! Currently happens for project_box.
|
|
|
|
// Compute the reference value's liveness.
|
|
SSAPrunedLiveness liveness;
|
|
liveness.initializeDef(root);
|
|
SimpleLiveRangeSummary summary = liveness.computeSimple();
|
|
// Conservatively ignore InnerBorrowKind::Reborrowed and
|
|
// AddressUseKind::PointerEscape and Reborrowed. The resulting liveness at
|
|
// least covers the known uses.
|
|
(void)summary;
|
|
|
|
// FIXME (implicit borrow): handle reborrows transitively just like above so
|
|
// we don't bail out if a uses is within the reborrowed scope.
|
|
return liveness.areUsesWithinBoundary(uses, &deadEndBlocks);
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Owned Value Introducers
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
void OwnedValueIntroducerKind::print(llvm::raw_ostream &os) const {
|
|
switch (value) {
|
|
case OwnedValueIntroducerKind::Invalid:
|
|
llvm_unreachable("Using invalid case?!");
|
|
case OwnedValueIntroducerKind::Apply:
|
|
os << "Apply";
|
|
return;
|
|
case OwnedValueIntroducerKind::BeginApply:
|
|
os << "BeginApply";
|
|
return;
|
|
case OwnedValueIntroducerKind::TryApply:
|
|
os << "TryApply";
|
|
return;
|
|
case OwnedValueIntroducerKind::Copy:
|
|
os << "Copy";
|
|
return;
|
|
case OwnedValueIntroducerKind::LoadCopy:
|
|
os << "LoadCopy";
|
|
return;
|
|
case OwnedValueIntroducerKind::LoadTake:
|
|
os << "LoadTake";
|
|
return;
|
|
case OwnedValueIntroducerKind::Phi:
|
|
os << "Phi";
|
|
return;
|
|
case OwnedValueIntroducerKind::Struct:
|
|
os << "Struct";
|
|
return;
|
|
case OwnedValueIntroducerKind::Tuple:
|
|
os << "Tuple";
|
|
return;
|
|
case OwnedValueIntroducerKind::FunctionArgument:
|
|
os << "FunctionArgument";
|
|
return;
|
|
case OwnedValueIntroducerKind::PartialApplyInit:
|
|
os << "PartialApplyInit";
|
|
return;
|
|
case OwnedValueIntroducerKind::AllocBoxInit:
|
|
os << "AllocBoxInit";
|
|
return;
|
|
case OwnedValueIntroducerKind::AllocRefInit:
|
|
os << "AllocRefInit";
|
|
return;
|
|
}
|
|
llvm_unreachable("Covered switch isn't covered");
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Introducer Searching Routines
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
bool swift::getAllBorrowIntroducingValues(SILValue inputValue,
|
|
SmallVectorImpl<BorrowedValue> &out) {
|
|
if (inputValue->getOwnershipKind() != OwnershipKind::Guaranteed)
|
|
return false;
|
|
|
|
SmallSetVector<SILValue, 32> worklist;
|
|
worklist.insert(inputValue);
|
|
|
|
// worklist grows in this loop.
|
|
for (unsigned idx = 0; idx < worklist.size(); idx++) {
|
|
SILValue value = worklist[idx];
|
|
|
|
// First check if v is an introducer. If so, stash it and continue.
|
|
if (auto scopeIntroducer = BorrowedValue(value)) {
|
|
out.push_back(scopeIntroducer);
|
|
continue;
|
|
}
|
|
|
|
// If v produces .none ownership, then we can ignore it. It is important
|
|
// that we put this before checking for guaranteed forwarding instructions,
|
|
// since we want to ignore guaranteed forwarding instructions that in this
|
|
// specific case produce a .none value.
|
|
if (value->getOwnershipKind() == OwnershipKind::None)
|
|
continue;
|
|
|
|
// Otherwise if v is an ownership forwarding value, add its defining
|
|
// instruction
|
|
if (isGuaranteedForwarding(value)) {
|
|
if (auto *i = value->getDefiningInstruction()) {
|
|
for (SILValue opValue : i->getNonTypeDependentOperandValues()) {
|
|
worklist.insert(opValue);
|
|
}
|
|
continue;
|
|
}
|
|
|
|
// Otherwise, we should have a block argument that is defined by a single
|
|
// predecessor terminator.
|
|
auto *arg = cast<SILPhiArgument>(value);
|
|
if (arg->isTerminatorResult()) {
|
|
if (auto *forwardedOper = arg->forwardedTerminatorResultOperand()) {
|
|
worklist.insert(forwardedOper->get());
|
|
continue;
|
|
}
|
|
}
|
|
arg->visitIncomingPhiOperands([&](auto *operand) {
|
|
worklist.insert(operand->get());
|
|
return true;
|
|
});
|
|
}
|
|
|
|
// Otherwise, this is an introducer we do not understand. Bail and return
|
|
// false.
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
// FIXME: replace this logic with AccessBase::findOwnershipReferenceRoot.
|
|
BorrowedValue swift::getSingleBorrowIntroducingValue(SILValue inputValue) {
|
|
if (inputValue->getOwnershipKind() != OwnershipKind::Guaranteed)
|
|
return {};
|
|
|
|
SILValue currentValue = inputValue;
|
|
while (true) {
|
|
// First check if our initial value is an introducer. If we have one, just
|
|
// return it.
|
|
if (auto scopeIntroducer = BorrowedValue(currentValue)) {
|
|
return scopeIntroducer;
|
|
}
|
|
|
|
if (currentValue->getOwnershipKind() == OwnershipKind::None)
|
|
return {};
|
|
|
|
// Otherwise if v is an ownership forwarding value, add its defining
|
|
// instruction
|
|
if (isGuaranteedForwarding(currentValue)) {
|
|
if (auto *i = currentValue->getDefiningInstructionOrTerminator()) {
|
|
auto instOps = i->getNonTypeDependentOperandValues();
|
|
// If we have multiple incoming values, return .None. We can't handle
|
|
// this.
|
|
auto begin = instOps.begin();
|
|
if (std::next(begin) != instOps.end()) {
|
|
return {};
|
|
}
|
|
// Otherwise, set currentOp to the single operand and continue.
|
|
currentValue = *begin;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Otherwise, this is an introducer we do not understand. Bail and return
|
|
// None.
|
|
return {};
|
|
}
|
|
|
|
llvm_unreachable("Should never hit this");
|
|
}
|
|
|
|
bool swift::getAllOwnedValueIntroducers(
|
|
SILValue inputValue, SmallVectorImpl<OwnedValueIntroducer> &out) {
|
|
if (inputValue->getOwnershipKind() != OwnershipKind::Owned)
|
|
return false;
|
|
|
|
SmallVector<SILValue, 32> worklist;
|
|
worklist.emplace_back(inputValue);
|
|
|
|
while (!worklist.empty()) {
|
|
SILValue value = worklist.pop_back_val();
|
|
|
|
// First check if v is an introducer. If so, stash it and continue.
|
|
if (auto introducer = OwnedValueIntroducer::get(value)) {
|
|
out.push_back(introducer);
|
|
continue;
|
|
}
|
|
|
|
// If v produces .none ownership, then we can ignore it. It is important
|
|
// that we put this before checking for guaranteed forwarding instructions,
|
|
// since we want to ignore guaranteed forwarding instructions that in this
|
|
// specific case produce a .none value.
|
|
if (value->getOwnershipKind() == OwnershipKind::None)
|
|
continue;
|
|
|
|
// Otherwise if v is an ownership forwarding value, add its defining
|
|
// instruction
|
|
if (isForwardingConsume(value)) {
|
|
if (auto *i = value->getDefiningInstructionOrTerminator()) {
|
|
llvm::copy(i->getNonTypeDependentOperandValues(),
|
|
std::back_inserter(worklist));
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Otherwise, this is an introducer we do not understand. Bail and return
|
|
// false.
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
OwnedValueIntroducer swift::getSingleOwnedValueIntroducer(SILValue inputValue) {
|
|
if (inputValue->getOwnershipKind() != OwnershipKind::Owned)
|
|
return {};
|
|
|
|
SILValue currentValue = inputValue;
|
|
while (true) {
|
|
// First check if our initial value is an introducer. If we have one, just
|
|
// return it.
|
|
if (auto introducer = OwnedValueIntroducer::get(currentValue)) {
|
|
return introducer;
|
|
}
|
|
|
|
// Otherwise if v is an ownership forwarding value, add its defining
|
|
// instruction
|
|
if (isForwardingConsume(currentValue)) {
|
|
if (auto *i = currentValue->getDefiningInstructionOrTerminator()) {
|
|
auto instOps = i->getNonTypeDependentOperandValues();
|
|
// If we have multiple incoming values, return .None. We can't handle
|
|
// this.
|
|
auto begin = instOps.begin();
|
|
if (std::next(begin) != instOps.end()) {
|
|
return {};
|
|
}
|
|
// Otherwise, set currentOp to the single operand and continue.
|
|
currentValue = *begin;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Otherwise, this is an introducer we do not understand. Bail and return
|
|
// None.
|
|
return {};
|
|
}
|
|
|
|
llvm_unreachable("Should never hit this");
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Forwarding Operand
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
ForwardingOperand::ForwardingOperand(Operand *use) {
|
|
if (use->isTypeDependent())
|
|
return;
|
|
|
|
switch (use->getOperandOwnership()) {
|
|
case OperandOwnership::ForwardingUnowned:
|
|
case OperandOwnership::ForwardingConsume:
|
|
case OperandOwnership::GuaranteedForwarding:
|
|
this->use = use;
|
|
break;
|
|
default:
|
|
this->use = nullptr;
|
|
return;
|
|
}
|
|
}
|
|
|
|
ValueOwnershipKind ForwardingOperand::getForwardingOwnershipKind() const {
|
|
auto *user = use->getUser();
|
|
|
|
// NOTE: This if chain is meant to be a covered switch, so make sure to return
|
|
// in each if itself since we have an unreachable at the bottom to ensure if a
|
|
// new subclass of OwnershipForwardingInst is added
|
|
if (auto *ofsvi = dyn_cast<AllArgOwnershipForwardingSingleValueInst>(user))
|
|
return ofsvi->getForwardingOwnershipKind();
|
|
|
|
if (auto *ofsvi = dyn_cast<FirstArgOwnershipForwardingSingleValueInst>(user))
|
|
return ofsvi->getForwardingOwnershipKind();
|
|
|
|
if (auto *ofci = dyn_cast<OwnershipForwardingConversionInst>(user))
|
|
return ofci->getForwardingOwnershipKind();
|
|
|
|
if (auto *ofseib = dyn_cast<OwnershipForwardingSelectEnumInstBase>(user))
|
|
return ofseib->getForwardingOwnershipKind();
|
|
|
|
if (auto *ofmvi =
|
|
dyn_cast<OwnershipForwardingMultipleValueInstruction>(user)) {
|
|
assert(ofmvi->getNumOperands() == 1);
|
|
return ofmvi->getForwardingOwnershipKind();
|
|
}
|
|
|
|
if (auto *ofti = dyn_cast<OwnershipForwardingTermInst>(user)) {
|
|
assert(ofti->getNumOperands() == 1);
|
|
return ofti->getForwardingOwnershipKind();
|
|
}
|
|
|
|
if (auto *move = dyn_cast<MoveOnlyWrapperToCopyableValueInst>(user)) {
|
|
return move->getForwardingOwnershipKind();
|
|
}
|
|
|
|
llvm_unreachable("Unhandled forwarding inst?!");
|
|
}
|
|
|
|
void ForwardingOperand::setForwardingOwnershipKind(
|
|
ValueOwnershipKind newKind) const {
|
|
auto *user = use->getUser();
|
|
// NOTE: This if chain is meant to be a covered switch, so make sure to return
|
|
// in each if itself since we have an unreachable at the bottom to ensure if a
|
|
// new subclass of OwnershipForwardingInst is added
|
|
if (auto *ofsvi = dyn_cast<AllArgOwnershipForwardingSingleValueInst>(user))
|
|
return ofsvi->setForwardingOwnershipKind(newKind);
|
|
if (auto *ofsvi = dyn_cast<FirstArgOwnershipForwardingSingleValueInst>(user))
|
|
return ofsvi->setForwardingOwnershipKind(newKind);
|
|
if (auto *ofci = dyn_cast<OwnershipForwardingConversionInst>(user))
|
|
return ofci->setForwardingOwnershipKind(newKind);
|
|
if (auto *ofseib = dyn_cast<OwnershipForwardingSelectEnumInstBase>(user))
|
|
return ofseib->setForwardingOwnershipKind(newKind);
|
|
if (auto *ofmvi = dyn_cast<OwnershipForwardingMultipleValueInstruction>(user)) {
|
|
assert(ofmvi->getNumOperands() == 1);
|
|
if (!ofmvi->getOperand(0)->getType().isTrivial(*ofmvi->getFunction())) {
|
|
ofmvi->setForwardingOwnershipKind(newKind);
|
|
// TODO: Refactor this better.
|
|
if (auto *dsi = dyn_cast<DestructureStructInst>(ofmvi)) {
|
|
for (auto &result : dsi->getAllResultsBuffer()) {
|
|
if (result.getType().isTrivial(*dsi->getFunction()))
|
|
continue;
|
|
result.setOwnershipKind(newKind);
|
|
}
|
|
} else {
|
|
auto *dti = cast<DestructureTupleInst>(ofmvi);
|
|
for (auto &result : dti->getAllResultsBuffer()) {
|
|
if (result.getType().isTrivial(*dti->getFunction()))
|
|
continue;
|
|
result.setOwnershipKind(newKind);
|
|
}
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (auto *ofti = dyn_cast<OwnershipForwardingTermInst>(user)) {
|
|
assert(ofti->getNumOperands() == 1);
|
|
if (!ofti->getOperand()->getType().isTrivial(*ofti->getFunction())) {
|
|
ofti->setForwardingOwnershipKind(newKind);
|
|
|
|
// Then convert all of its incoming values that are owned to be guaranteed.
|
|
for (auto &succ : ofti->getSuccessors()) {
|
|
auto *succBlock = succ.getBB();
|
|
|
|
// If we do not have any arguments, then continue.
|
|
if (succBlock->args_empty())
|
|
continue;
|
|
|
|
for (auto *succArg : succBlock->getSILPhiArguments()) {
|
|
// If we have an any value, just continue.
|
|
if (!succArg->getType().isTrivial(*ofti->getFunction()))
|
|
continue;
|
|
succArg->setOwnershipKind(newKind);
|
|
}
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
assert(
|
|
!isa<MoveOnlyWrapperToCopyableValueInst>(user) &&
|
|
"MoveOnlyWrapperToCopyableValueInst can not have its ownership changed");
|
|
|
|
llvm_unreachable("Out of sync with OperandOwnership");
|
|
}
|
|
|
|
void ForwardingOperand::replaceOwnershipKind(ValueOwnershipKind oldKind,
|
|
ValueOwnershipKind newKind) const {
|
|
auto *user = use->getUser();
|
|
|
|
if (auto *fInst = dyn_cast<AllArgOwnershipForwardingSingleValueInst>(user))
|
|
if (fInst->getForwardingOwnershipKind() == oldKind)
|
|
return fInst->setForwardingOwnershipKind(newKind);
|
|
|
|
if (auto *fInst = dyn_cast<FirstArgOwnershipForwardingSingleValueInst>(user))
|
|
if (fInst->getForwardingOwnershipKind() == oldKind)
|
|
return fInst->setForwardingOwnershipKind(newKind);
|
|
|
|
if (auto *ofci = dyn_cast<OwnershipForwardingConversionInst>(user))
|
|
if (ofci->getForwardingOwnershipKind() == oldKind)
|
|
return ofci->setForwardingOwnershipKind(newKind);
|
|
|
|
if (auto *ofseib = dyn_cast<OwnershipForwardingSelectEnumInstBase>(user))
|
|
if (ofseib->getForwardingOwnershipKind() == oldKind)
|
|
return ofseib->setForwardingOwnershipKind(newKind);
|
|
|
|
if (auto *ofmvi = dyn_cast<OwnershipForwardingMultipleValueInstruction>(user)) {
|
|
if (ofmvi->getForwardingOwnershipKind() == oldKind) {
|
|
ofmvi->setForwardingOwnershipKind(newKind);
|
|
}
|
|
// TODO: Refactor this better.
|
|
if (auto *dsi = dyn_cast<DestructureStructInst>(ofmvi)) {
|
|
for (auto &result : dsi->getAllResultsBuffer()) {
|
|
if (result.getOwnershipKind() != oldKind)
|
|
continue;
|
|
result.setOwnershipKind(newKind);
|
|
}
|
|
} else {
|
|
auto *dti = cast<DestructureTupleInst>(ofmvi);
|
|
for (auto &result : dti->getAllResultsBuffer()) {
|
|
if (result.getOwnershipKind() != oldKind)
|
|
continue;
|
|
result.setOwnershipKind(newKind);
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (auto *ofti = dyn_cast<OwnershipForwardingTermInst>(user)) {
|
|
if (ofti->getForwardingOwnershipKind() == oldKind) {
|
|
ofti->setForwardingOwnershipKind(newKind);
|
|
// Then convert all of its incoming values that are owned to be guaranteed.
|
|
for (auto &succ : ofti->getSuccessors()) {
|
|
auto *succBlock = succ.getBB();
|
|
|
|
// If we do not have any arguments, then continue.
|
|
if (succBlock->args_empty())
|
|
continue;
|
|
|
|
for (auto *succArg : succBlock->getSILPhiArguments()) {
|
|
// If we have an any value, just continue.
|
|
if (succArg->getOwnershipKind() == oldKind) {
|
|
succArg->setOwnershipKind(newKind);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
assert(
|
|
!isa<MoveOnlyWrapperToCopyableValueInst>(user) &&
|
|
"MoveOnlyWrapperToCopyableValueInst can not have its ownership changed");
|
|
|
|
llvm_unreachable("Missing Case! Out of sync with OperandOwnership");
|
|
}
|
|
|
|
SILValue ForwardingOperand::getSingleForwardedValue() const {
|
|
if (auto *svi = dyn_cast<SingleValueInstruction>(use->getUser()))
|
|
return svi;
|
|
return SILValue();
|
|
}
|
|
|
|
bool ForwardingOperand::visitForwardedValues(
|
|
function_ref<bool(SILValue)> visitor) {
|
|
auto *user = use->getUser();
|
|
|
|
// See if we have a single value instruction... if we do that is always the
|
|
// transitive result.
|
|
if (auto *svi = dyn_cast<SingleValueInstruction>(user)) {
|
|
return visitor(svi);
|
|
}
|
|
|
|
if (auto *mvri = dyn_cast<MultipleValueInstruction>(user)) {
|
|
return llvm::all_of(mvri->getResults(), [&](SILValue value) {
|
|
if (value->getOwnershipKind() == OwnershipKind::None)
|
|
return true;
|
|
return visitor(value);
|
|
});
|
|
}
|
|
|
|
// This is an instruction like switch_enum and checked_cast_br that are
|
|
// "transforming terminators"... We know that this means that we should at
|
|
// most have a single phi argument.
|
|
auto *ti = cast<TermInst>(user);
|
|
if (ti->mayHaveTerminatorResult()) {
|
|
return llvm::all_of(
|
|
ti->getSuccessorBlocks(), [&](SILBasicBlock *succBlock) {
|
|
// If we do not have any arguments, then continue.
|
|
if (succBlock->args_empty())
|
|
return true;
|
|
|
|
auto args = succBlock->getSILPhiArguments();
|
|
assert(args.size() == 1 &&
|
|
"Transforming terminator with multiple args?!");
|
|
return visitor(args[0]);
|
|
});
|
|
}
|
|
|
|
auto *succArg = PhiOperand(use).getValue();
|
|
return visitor(succArg);
|
|
}
|
|
|
|
void swift::visitExtendedReborrowPhiBaseValuePairs(
|
|
BeginBorrowInst *borrowInst, function_ref<void(SILPhiArgument *, SILValue)>
|
|
visitReborrowPhiBaseValuePair) {
|
|
// A Reborrow can have different base values on different control flow
|
|
// paths.
|
|
// For that reason, worklist stores (reborrow, base value) pairs.
|
|
// We need a SetVector to make sure we don't revisit the same pair again.
|
|
SmallSetVector<std::tuple<PhiOperand, SILValue>, 4> worklist;
|
|
|
|
// Find all reborrows of value and insert the (reborrow, base value) pair into
|
|
// the worklist.
|
|
auto collectReborrows = [&](SILValue value, SILValue baseValue) {
|
|
BorrowedValue(value).visitLocalScopeEndingUses([&](Operand *op) {
|
|
if (op->getOperandOwnership() == OperandOwnership::Reborrow) {
|
|
worklist.insert(std::make_tuple(PhiOperand(op), baseValue));
|
|
}
|
|
return true;
|
|
});
|
|
};
|
|
|
|
// Initialize the worklist.
|
|
collectReborrows(borrowInst, borrowInst->getOperand());
|
|
|
|
// For every (reborrow, base value) pair in the worklist:
|
|
// - Find phi value and new base value
|
|
// - Call the visitor on the phi value and new base value pair
|
|
// - Populate the worklist with pairs of reborrows of phi value and the new
|
|
// base.
|
|
for (unsigned idx = 0; idx < worklist.size(); idx++) {
|
|
PhiOperand phiOp;
|
|
SILValue currentBaseValue;
|
|
std::tie(phiOp, currentBaseValue) = worklist[idx];
|
|
|
|
auto *phiValue = phiOp.getValue();
|
|
SILValue newBaseValue = currentBaseValue;
|
|
|
|
// If the previous base value was also passed as a phi operand along with
|
|
// the reborrow, its phi value will be the new base value.
|
|
for (auto &op : phiOp.getBranch()->getAllOperands()) {
|
|
PhiOperand otherPhiOp(&op);
|
|
if (otherPhiOp.getSource() != currentBaseValue) {
|
|
continue;
|
|
}
|
|
newBaseValue = otherPhiOp.getValue();
|
|
}
|
|
|
|
// Call the visitor function
|
|
visitReborrowPhiBaseValuePair(phiValue, newBaseValue);
|
|
|
|
collectReborrows(phiValue, newBaseValue);
|
|
}
|
|
}
|
|
|
|
void swift::visitExtendedGuaranteedForwardingPhiBaseValuePairs(
|
|
BorrowedValue borrow, function_ref<void(SILPhiArgument *, SILValue)>
|
|
visitGuaranteedForwardingPhiBaseValuePair) {
|
|
assert(borrow.kind == BorrowedValueKind::BeginBorrow ||
|
|
borrow.kind == BorrowedValueKind::LoadBorrow);
|
|
// A GuaranteedForwardingPhi can have different base values on different
|
|
// control flow paths.
|
|
// For that reason, worklist stores (GuaranteedForwardingPhi operand, base
|
|
// value) pairs. We need a SetVector to make sure we don't revisit the same
|
|
// pair again.
|
|
SmallSetVector<std::tuple<PhiOperand, SILValue>, 4> worklist;
|
|
|
|
auto collectGuaranteedForwardingPhis = [&](SILValue value,
|
|
SILValue baseValue) {
|
|
visitGuaranteedForwardingPhisForSSAValue(value, [&](Operand *op) {
|
|
worklist.insert(std::make_tuple(PhiOperand(op), baseValue));
|
|
return true;
|
|
});
|
|
};
|
|
|
|
// Collect all GuaranteedForwardingPhis
|
|
collectGuaranteedForwardingPhis(borrow.value, borrow.value);
|
|
borrow.visitTransitiveLifetimeEndingUses([&](Operand *endUse) {
|
|
if (endUse->getOperandOwnership() == OperandOwnership::Reborrow) {
|
|
auto *phiValue = PhiOperand(endUse).getValue();
|
|
collectGuaranteedForwardingPhis(phiValue, phiValue);
|
|
}
|
|
return true;
|
|
});
|
|
// For every (GuaranteedForwardingPhi operand, base value) pair in the
|
|
// worklist:
|
|
// - Find phi value and new base value
|
|
// - Call the visitor on the phi value and new base value pair
|
|
// - Populate the worklist with pairs of GuaranteedForwardingPhi ops of phi
|
|
// value and the new base.
|
|
for (unsigned idx = 0; idx < worklist.size(); idx++) {
|
|
PhiOperand phiOp;
|
|
SILValue currentBaseValue;
|
|
std::tie(phiOp, currentBaseValue) = worklist[idx];
|
|
|
|
auto *phiValue = phiOp.getValue();
|
|
SILValue newBaseValue = currentBaseValue;
|
|
|
|
// If an adjacent reborrow is found in the same block as the guaranteed phi,
|
|
// then set newBaseValue to the reborrow.
|
|
for (auto &op : phiOp.getBranch()->getAllOperands()) {
|
|
PhiOperand otherPhiOp(&op);
|
|
if (otherPhiOp.getSource() != currentBaseValue) {
|
|
continue;
|
|
}
|
|
newBaseValue = otherPhiOp.getValue();
|
|
}
|
|
|
|
// Call the visitor function
|
|
visitGuaranteedForwardingPhiBaseValuePair(phiValue, newBaseValue);
|
|
|
|
collectGuaranteedForwardingPhis(phiValue, newBaseValue);
|
|
}
|
|
}
|
|
|
|
/// If \p instruction forwards guaranteed values to its results, visit each
|
|
/// forwarded operand. The visitor must check whether the forwarded value is
|
|
/// guaranteed.
|
|
///
|
|
/// Return true \p visitOperand was called at least once.
|
|
///
|
|
/// \p visitOperand should always recheck for Guaranteed owernship if it
|
|
/// matters, in case a cast forwards a trivial type to a nontrivial type.
|
|
///
|
|
/// This intentionally does not handle phis, which require recursive traversal
|
|
/// to determine `isGuaranteedForwardingPhi`.
|
|
bool swift::visitForwardedGuaranteedOperands(
|
|
SILValue value, function_ref<void(Operand *)> visitOperand) {
|
|
|
|
assert(!SILArgument::asPhi(value) && "phis are handled separately");
|
|
|
|
if (auto *termResult = SILArgument::isTerminatorResult(value)) {
|
|
if (auto *oper = termResult->forwardedTerminatorResultOperand()) {
|
|
visitOperand(oper);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
auto *inst = value->getDefiningInstruction();
|
|
if (!inst)
|
|
return false;
|
|
|
|
// Bypass conversions that produce a guarantee value out of thin air.
|
|
if (inst->getNumRealOperands() == 0) {
|
|
return false;
|
|
}
|
|
if (isa<FirstArgOwnershipForwardingSingleValueInst>(inst)
|
|
|| isa<OwnershipForwardingConversionInst>(inst)
|
|
|| isa<OwnershipForwardingSelectEnumInstBase>(inst)
|
|
|| isa<OwnershipForwardingMultipleValueInstruction>(inst)
|
|
|| isa<MoveOnlyWrapperToCopyableValueInst>(inst)
|
|
|| isa<CopyableToMoveOnlyWrapperValueInst>(inst)) {
|
|
assert(inst->getNumRealOperands() == 1
|
|
&& "forwarding instructions must have a single real operand");
|
|
assert(!isa<SingleValueInstruction>(inst)
|
|
|| !BorrowedValue(cast<SingleValueInstruction>(inst))
|
|
&& "forwarded operand cannot begin a borrow scope");
|
|
visitOperand(&inst->getOperandRef(0));
|
|
return true;
|
|
}
|
|
if (isa<AllArgOwnershipForwardingSingleValueInst>(inst)) {
|
|
assert(inst->getNumOperands() > 0 && "checked above");
|
|
assert(inst->getNumOperands() == inst->getNumRealOperands() &&
|
|
"mixin expects all readl operands");
|
|
for (auto &operand : inst->getAllOperands()) {
|
|
visitOperand(&operand);
|
|
}
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// Visit the phis in the same block as \p phi which are reborrows of a borrow
|
|
/// of one of the values reaching \p phi.
|
|
///
|
|
/// If the visitor returns false, stops visiting and returns false. Otherwise,
|
|
/// returns true.
|
|
///
|
|
///
|
|
/// When an owned value is passed as a phi argument, it is consumed. So any
|
|
/// open scope borrowing that owned value must be ended no later than in that
|
|
/// branch instruction. Either such a borrow scope is ended beforehand
|
|
/// %lifetime = begin_borrow %value
|
|
/// ...
|
|
/// end_borrow %lifetime <-- borrow scope ended here
|
|
/// br block(%value) <-- before consume
|
|
/// or the borrow scope is ended in the same instruction as the owned value is
|
|
/// consumed
|
|
/// %lifetime = begin_borrow %value
|
|
/// ...
|
|
/// end_borrow %lifetime
|
|
/// br block(%value, %lifetime) <-- borrow scope ended here
|
|
/// <-- in same instruction as consume
|
|
/// In particular, the following is invalid
|
|
/// %lifetime = begin_borrow %value
|
|
/// ...
|
|
/// br block(%value)
|
|
/// block(%value_2 : @owned):
|
|
/// end_borrow %lifetime
|
|
/// destroy_value %value_2
|
|
/// because %lifetime was guaranteed by %value but value is consumed at
|
|
/// `br two`.
|
|
///
|
|
/// Similarly, when a guaranteed value is passed as a phi argument, its borrow
|
|
/// scope ends and a new borrow scope is begun. And so any open nested borrow
|
|
/// of the original outer borrow must be ended no later than in that branch
|
|
/// instruction.
|
|
///
|
|
///
|
|
/// Given an phi argument
|
|
/// block(..., %value : @owned, ...)
|
|
/// this function finds the adjacent reborrow phis
|
|
/// block(..., %lifetime : @guaranteed, ..., %value : @owned, ...)
|
|
/// ^^^^^^^^^^^^^^^^^^^^^^^
|
|
/// one of whose reaching values is a borrow of a reaching value of %value.
|
|
///
|
|
/// In both cases, finding an adjacent phi may be more complicated than merely
|
|
/// looking for guaranteed operands adjacent to the incoming operands to phi
|
|
/// and which are borrows of the value whose lifetime ends there. The reason is
|
|
/// that they might not be borrows of that incoming value _directly_ but rather
|
|
/// reborrows of some other reborrow:
|
|
///
|
|
/// %lifetime = begin_borrow %value
|
|
/// br one(%value, %lifetime)
|
|
/// one(%value_1 : @owned, %lifetime_1 : @guaranteed)
|
|
/// br two(%value_1, %lifetime_1)
|
|
/// two(%value_2 : @owned, %lifetime_2 : @guaranteed)
|
|
/// end_borrow %lifetime_2
|
|
/// destroy_value %value_2
|
|
///
|
|
/// When called with %value_2, \p visitor is invoked with:
|
|
/// two(%value_2 : @owned, %lifetime_2 : @guaranteed)
|
|
/// ^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
///
|
|
/// FIXME: this does not correctly handle dominated phis:
|
|
///
|
|
/// %value = ...
|
|
/// %borrow = begin_borrow %value
|
|
/// br one(%borrow)
|
|
/// one(%reborrow_1 : @guaranteed)
|
|
/// br two(%value, %reborrow_1)
|
|
/// two(%phi_2 : @owned, %reborrow_2 : @guaranteed)
|
|
/// br three(%value, %reborrow_1)
|
|
///
|
|
/// Instead, just call findEnclosingDefs for each guaranteed phi in the same
|
|
/// block and visit any that match.
|
|
///
|
|
/// FIXME: this does not correctly handle guaranteed phis
|
|
///
|
|
/// %borrow = begin_borrow %value
|
|
/// %field = struct_extract %borrow
|
|
/// br one(%borrow, %field)
|
|
/// one(%reborrow : @guaranteed, %forwardingphi : @guaranteed)
|
|
///
|
|
bool swift::visitAdjacentReborrowsOfPhi(
|
|
SILPhiArgument *phi, function_ref<bool(SILPhiArgument *)> visitor) {
|
|
assert(phi->isPhi());
|
|
|
|
// First, collect all the values that reach \p phi, that is:
|
|
// - operands to the phi
|
|
// - operands to phis which are operands to the phi
|
|
// - and so forth.
|
|
SmallPtrSet<SILValue, 8> reachingValues;
|
|
// At the same time, record all the phis in \p phi's phi web: the phis which
|
|
// are transitively operands to \p phi. This is the subset of \p
|
|
// reachingValues that are phis.
|
|
SmallVector<SILPhiArgument *, 4> phis;
|
|
phi->visitTransitiveIncomingPhiOperands(
|
|
[&](auto *phi, auto *operand) -> bool {
|
|
phis.push_back(phi);
|
|
reachingValues.insert(phi);
|
|
reachingValues.insert(operand->get());
|
|
return true;
|
|
});
|
|
|
|
// Second, find all the guaranteed phis one of whose operands _could_ (by
|
|
// dint of being adjacent to a phi in the phi web with the appropriate
|
|
// ownership and type) be a reborrow of a reaching value of \p phi.
|
|
SmallVector<SILPhiArgument *, 4> candidates;
|
|
for (auto *phi : phis) {
|
|
SILBasicBlock *block = phi->getParentBlock();
|
|
for (auto *uncastAdjacent : block->getArguments()) {
|
|
auto *adjacent = cast<SILPhiArgument>(uncastAdjacent);
|
|
if (adjacent == phi)
|
|
continue;
|
|
if (adjacent->getType() != phi->getType())
|
|
continue;
|
|
if (adjacent->getOwnershipKind() != OwnershipKind::Guaranteed)
|
|
continue;
|
|
candidates.push_back(adjacent);
|
|
}
|
|
}
|
|
|
|
// Finally, look through \p candidates to find those one of whose incoming
|
|
// operands either
|
|
// (1) borrow one of reaching values of \p phi
|
|
// or (2) is itself a guaranteed phi which does so.
|
|
// Because we may discover a reborrow R1 of type (1) after visiting another
|
|
// R2 of type (2) which reborrows R1, we need to iterate to a fixed point.
|
|
//
|
|
// Record all the phis that we see which are borrows or reborrows of a
|
|
// reaching value \p so that we can check for case (2) above.
|
|
//
|
|
// Visit those phis which are both reborrows of a reaching value AND are in
|
|
// the same block as \phi.
|
|
//
|
|
// For example, given
|
|
//
|
|
// %lifetime = begin_borrow %value
|
|
// br one(%value, %lifetime)
|
|
// one(%value_1 : @owned, %lifetime_1 : @guaranteed)
|
|
// br two(%value_1, %lifetime_1)
|
|
// two(%value_2 : @owned, %lifetime_2 : @guaranteed)
|
|
// end_borrow %lifetime_2
|
|
// destroy_value %value_2
|
|
//
|
|
// when visiting the reborrow phis adjacent to %value_2, The following steps
|
|
// would be taken:
|
|
//
|
|
// (1) Look at the first candidate:
|
|
// two(%value_2 : @owned, %lifetime_2 : @guaranteed)
|
|
// ^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
// but see that its one incoming value
|
|
// br two(%value_1, %lifetime_1)
|
|
// ^^^^^^^^^^^
|
|
// although a phi argument itself, is not known (yet!) to be a reborrow phi.
|
|
// So the first candidate is NOT (yet!) added to reborrowPhis.
|
|
//
|
|
// (2) Look at the second candidate:
|
|
// one(%value_1 : @owned, %lifetime_1 : @guaranteed)
|
|
// ^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
// and see that one of its incoming values
|
|
// br one(%value, %lifetime)
|
|
// ^^^^^^^^^
|
|
// is a borrow
|
|
// %lifetime = begin_borrow %value
|
|
// of %value, one of the values reaching %value_2.
|
|
// So the second candidate IS added to reborrowPhis.
|
|
// AND changed is set to true, so we will repeat the outer loop.
|
|
// But this candidate is not adjacent to our phi %value_2, so it is not
|
|
// visited.
|
|
//
|
|
// (4.5) Changed is true: repeat the outer loop. Set changed to false.
|
|
//
|
|
// (3) Look at the first candidate:
|
|
// two(%value_2 : @owned, %lifetime_2 : @guaranteed)
|
|
// ^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
// and see that one of its incoming values
|
|
// br two(%value_1, %lifetime_1)
|
|
// ^^^^^^^^^^^
|
|
// is itself a phi
|
|
// one(%value_1 : @owned, %lifetime_1 : @guaranteed)
|
|
// ^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
// which was added to reborrowPhis in (2).
|
|
// So the first candidate IS added to reborrowPhis.
|
|
// AND changed is set to true.
|
|
// ALSO, see that the first candidate IS adjacent to our phi %value_2, so our
|
|
// visitor is invoked with the first candidate.
|
|
//
|
|
// (4) Look at the second candidate.
|
|
// See that it is already a member of reborrowPhis.
|
|
//
|
|
// (4.5) Changed is true: repeat the outer loop. Set changed to false.
|
|
//
|
|
// (5) Look at the first candidate.
|
|
// See that it is already a member of reborrowPhis.
|
|
//
|
|
// (6) Look at the second candidate.
|
|
// See that it is already a member of reborrowPhis.
|
|
//
|
|
// (6.5) Changed is false: exit the outer loop.
|
|
bool changed = false;
|
|
SmallSetVector<SILPhiArgument *, 4> reborrowPhis;
|
|
do {
|
|
changed = false;
|
|
for (auto *candidate : candidates) {
|
|
if (reborrowPhis.contains(candidate))
|
|
continue;
|
|
auto success = candidate->visitIncomingPhiOperands([&](auto *operand) {
|
|
// If the value being reborrowed is itself a reborrow of a value
|
|
// reaching \p phi, then visit it.
|
|
SILPhiArgument *forwarded;
|
|
if ((forwarded = dyn_cast<SILPhiArgument>(operand->get()))) {
|
|
if (!reborrowPhis.contains(forwarded))
|
|
return true;
|
|
changed = true;
|
|
reborrowPhis.insert(candidate);
|
|
if (candidate->getParentBlock() == phi->getParentBlock())
|
|
return visitor(candidate);
|
|
return true;
|
|
}
|
|
BeginBorrowInst *bbi;
|
|
if (!(bbi = dyn_cast<BeginBorrowInst>(operand->get())))
|
|
return true;
|
|
auto borrowee = bbi->getOperand();
|
|
if (!reachingValues.contains(borrowee))
|
|
return true;
|
|
changed = true;
|
|
reborrowPhis.insert(candidate);
|
|
if (candidate->getParentBlock() == phi->getParentBlock())
|
|
return visitor(candidate);
|
|
return true;
|
|
});
|
|
if (!success)
|
|
return false;
|
|
}
|
|
} while (changed);
|
|
|
|
return true;
|
|
}
|
|
|
|
namespace {
|
|
|
|
// Find the definitions of the scopes that enclose guaranteed values, handling
|
|
// all combinations of aggregation, guaranteed forwarding phis, and reborrows.
|
|
class FindEnclosingDefs {
|
|
// A separately allocated set-vector is used for each level of recursion
|
|
// across block boudndaries (NodeSet cannot be used recursively).
|
|
using LocalValueSetVector = SmallPtrSetVector<SILValue, 8>;
|
|
|
|
SILFunction *function;
|
|
ValueSet visitedPhis;
|
|
|
|
public:
|
|
FindEnclosingDefs(SILFunction *function) : function(function),
|
|
visitedPhis(function) {}
|
|
|
|
// Visit each definition of a scope that immediately encloses a guaranteed
|
|
// value. The guaranteed value effectively keeps these scopes alive.
|
|
//
|
|
// This means something different depending on whether \p value is itself a
|
|
// borrow introducer vs. a forwarded guaranteed value. If \p value is an
|
|
// introducer, then this disovers the enclosing borrow scope and visits all
|
|
// introducers of that scope. If \p value is a forwarded value, then this
|
|
// visits the introducers of the current borrow scope.
|
|
bool visitEnclosingDefs(SILValue value,
|
|
function_ref<bool(SILValue)> visitor) && {
|
|
if (value->getOwnershipKind() != OwnershipKind::Guaranteed)
|
|
return true;
|
|
|
|
if (auto borrowedValue = BorrowedValue(value)) {
|
|
switch (borrowedValue.kind) {
|
|
case BorrowedValueKind::Invalid:
|
|
llvm_unreachable("checked above");
|
|
|
|
case BorrowedValueKind::Phi: {
|
|
StackList<SILValue> enclosingDefs(function);
|
|
recursivelyFindDefsOfReborrow(SILArgument::asPhi(value), enclosingDefs);
|
|
for (SILValue def : enclosingDefs) {
|
|
if (!visitor(def))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
case BorrowedValueKind::BeginBorrow:
|
|
return std::move(*this).visitBorrowIntroducers(
|
|
cast<BeginBorrowInst>(value)->getOperand(), visitor);
|
|
|
|
case BorrowedValueKind::LoadBorrow:
|
|
case BorrowedValueKind::SILFunctionArgument:
|
|
// There is no enclosing def on this path.
|
|
return true;
|
|
}
|
|
}
|
|
// Handle forwarded guaranteed values.
|
|
return std::move(*this).visitBorrowIntroducers(value, visitor);
|
|
}
|
|
|
|
// Visit the values that introduce the borrow scopes that includes \p
|
|
// value. If value is owned, or introduces a borrow scope, then this only
|
|
// visits \p value.
|
|
bool visitBorrowIntroducers(SILValue value,
|
|
function_ref<bool(SILValue)> visitor) && {
|
|
StackList<SILValue> introducers(function);
|
|
LocalValueSetVector visitedValues;
|
|
recursivelyFindBorrowIntroducers(value, introducers, visitedValues);
|
|
for (SILValue introducer : introducers) {
|
|
if (!visitor(introducer))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
protected:
|
|
// This is the identity function (i.e. just adds \p value to \p introducers)
|
|
// when:
|
|
// - \p value is owned
|
|
// - \p value introduces a borrow scope (begin_borrow, load_borrow, reborrow)
|
|
//
|
|
// Otherwise recurse up the use-def chain to find all introducers.
|
|
//
|
|
// Returns false if \p forwardingPhi was already encountered, either because
|
|
// of a phi cycle or because of reconvergent control flow. Similarly, return
|
|
// false if all incoming values were encountered.
|
|
bool recursivelyFindBorrowIntroducers(SILValue value,
|
|
StackList<SILValue> &introducers,
|
|
LocalValueSetVector &visitedValues) {
|
|
// Check if this value's introducers have already been added to
|
|
// 'introducers' to avoid duplicates and avoid exponential recursion on
|
|
// aggregates.
|
|
if (!visitedValues.insert(value))
|
|
return false;
|
|
|
|
switch (value->getOwnershipKind()) {
|
|
case OwnershipKind::Any:
|
|
case OwnershipKind::None:
|
|
case OwnershipKind::Unowned:
|
|
return false;
|
|
|
|
case OwnershipKind::Owned:
|
|
introducers.push_back(value);
|
|
return true;
|
|
|
|
case OwnershipKind::Guaranteed:
|
|
break;
|
|
}
|
|
// BorrowedValue handles the initial scope introducers: begin_borrow,
|
|
// load_borrow, & reborrow.
|
|
if (BorrowedValue(value)) {
|
|
introducers.push_back(value);
|
|
return true;
|
|
}
|
|
bool foundNewIntroducer = false;
|
|
// Handle forwarding phis.
|
|
if (auto *phi = SILArgument::asPhi(value)) {
|
|
foundNewIntroducer = recursivelyFindForwardingPhiIntroducers(
|
|
phi, introducers, visitedValues);
|
|
} else {
|
|
// Recurse through guaranteed forwarding instructions.
|
|
visitForwardedGuaranteedOperands(value, [&](Operand *operand) {
|
|
SILValue forwardedVal = operand->get();
|
|
if (forwardedVal->getOwnershipKind() == OwnershipKind::Guaranteed) {
|
|
foundNewIntroducer |=
|
|
recursivelyFindBorrowIntroducers(forwardedVal, introducers,
|
|
visitedValues);
|
|
}
|
|
});
|
|
}
|
|
return foundNewIntroducer;
|
|
}
|
|
|
|
// Given the enclosing definition on a predecessor path, identify the
|
|
// enclosing definitions on the successor block. Each enclosing predecessor
|
|
// def is either used by an outer-adjacent phi in the successor block, or it
|
|
// must dominate the successor block.
|
|
static SILValue findSuccessorDefFromPredDef(SILBasicBlock *predecessor,
|
|
SILValue enclosingPredDef) {
|
|
|
|
SILBasicBlock *successor = predecessor->getSingleSuccessorBlock();
|
|
assert(successor && "phi predecessor must have a single successor in OSSA");
|
|
|
|
for (auto *candidatePhi : successor->getArguments()) {
|
|
SILValue candidateValue =
|
|
candidatePhi->getIncomingPhiValue(predecessor);
|
|
|
|
// Find the outer adjacent phi in the successor block.
|
|
// the 'enclosingDef' from the 'pred' block.
|
|
if (candidateValue == enclosingPredDef)
|
|
return candidatePhi;
|
|
}
|
|
// No candidates phi are outer-adjacent phis. The incoming enclosingDef
|
|
// must dominate the current guaranteed phi. So it remains the enclosing
|
|
// scope.
|
|
return enclosingPredDef;
|
|
}
|
|
|
|
// Given the enclosing definitions on a predecessor path, identify the
|
|
// enclosing definitions on the successor block.
|
|
void findSuccessorDefsFromPredDefs(
|
|
SILBasicBlock *predecessor, const StackList<SILValue> &predDefs,
|
|
StackList<SILValue> &successorDefs,
|
|
LocalValueSetVector &visitedSuccessorValues) {
|
|
|
|
// Gather the new introducers for the successor block.
|
|
for (SILValue predDef : predDefs) {
|
|
SILValue succDef = findSuccessorDefFromPredDef(predecessor, predDef);
|
|
if (visitedSuccessorValues.insert(succDef))
|
|
successorDefs.push_back(succDef);
|
|
}
|
|
}
|
|
|
|
// Find the introducers of a forwarding phi's borrow scope. The introducers
|
|
// are either dominating values, or reborrows in the same block as the
|
|
// forwarding phi.
|
|
//
|
|
// Recurse along the use-def phi web until a begin_borrow is reached. At each
|
|
// level, find the outer-adjacent phi, if one exists, otherwise return the
|
|
// dominating definition.
|
|
//
|
|
// Returns false if \p forwardingPhi was already encountered, either because
|
|
// of a phi cycle or because of reconvergent control flow. Similarly, returns
|
|
// false if all incoming values were encountered.
|
|
//
|
|
// one(%reborrow_1 : @guaranteed)
|
|
// %field = struct_extract %reborrow_1
|
|
// br two(%reborrow_1, %field)
|
|
// two(%reborrow_2 : @guaranteed, %forward_2 : @guaranteed)
|
|
// end_borrow %reborrow_2
|
|
//
|
|
// Calling recursivelyFindForwardingPhiIntroducers(%forward_2)
|
|
// recursively computes these introducers:
|
|
//
|
|
// %field is the only value incoming to %forward_2.
|
|
//
|
|
// %field is introduced by %reborrow_1 via
|
|
// recursivelyFindBorrowIntroducers(%field).
|
|
//
|
|
// %reborrow_1 is introduced by %reborrow_2 in block "two" via
|
|
// findSuccessorDefsFromPredDefs(%reborrow_1)).
|
|
//
|
|
// %reborrow_2 is returned.
|
|
//
|
|
bool
|
|
recursivelyFindForwardingPhiIntroducers(SILPhiArgument *forwardingPhi,
|
|
StackList<SILValue> &introducers,
|
|
LocalValueSetVector &visitedValues) {
|
|
// Phi cycles are skipped. They cannot contribute any new enclosing defs.
|
|
if (!visitedPhis.insert(forwardingPhi))
|
|
return false;
|
|
|
|
bool foundIntroducer = false;
|
|
SILBasicBlock *block = forwardingPhi->getParent();
|
|
for (auto *pred : block->getPredecessorBlocks()) {
|
|
SILValue incomingValue = forwardingPhi->getIncomingPhiValue(pred);
|
|
|
|
// Each phi operand requires a new introducer list and visited values
|
|
// set. These values will be remapped to successor phis before adding them
|
|
// to the caller's introducer list. It may be necessary to revisit a value
|
|
// that was already visited by the caller before remapping to phis.
|
|
StackList<SILValue> incomingIntroducers(function);
|
|
LocalValueSetVector incomingVisitedValues;
|
|
if (!recursivelyFindBorrowIntroducers(incomingValue, incomingIntroducers,
|
|
incomingVisitedValues))
|
|
continue;
|
|
|
|
foundIntroducer = true;
|
|
findSuccessorDefsFromPredDefs(pred, incomingIntroducers, introducers,
|
|
visitedValues);
|
|
}
|
|
return foundIntroducer;
|
|
}
|
|
|
|
// Given a reborrow operand's incoming value, find the enclosing definition.
|
|
void recursivelyFindDefsOfReborrowOperand(
|
|
SILValue incomingValue,
|
|
StackList<SILValue> &enclosingDefs) {
|
|
|
|
if (incomingValue->getOwnershipKind() == OwnershipKind::None)
|
|
return;
|
|
|
|
assert(incomingValue->getOwnershipKind() == OwnershipKind::Guaranteed);
|
|
|
|
// Avoid repeatedly constructing BorrowedValue during use-def
|
|
// traversal. That would be quadratic if it checks all uses for reborrows.
|
|
if (auto *predPhi = dyn_cast<SILPhiArgument>(incomingValue)) {
|
|
recursivelyFindDefsOfReborrow(predPhi, enclosingDefs);
|
|
return;
|
|
}
|
|
|
|
// Handle non-phi borrow introducers.
|
|
BorrowedValue borrowedValue(incomingValue);
|
|
|
|
switch (borrowedValue.kind) {
|
|
case BorrowedValueKind::Phi:
|
|
llvm_unreachable("phis are short-curcuited above");
|
|
case BorrowedValueKind::Invalid:
|
|
llvm_unreachable("A reborrow immediate operand must be a BorrowedValue.");
|
|
case BorrowedValueKind::BeginBorrow: {
|
|
LocalValueSetVector visitedValues;
|
|
recursivelyFindBorrowIntroducers(
|
|
cast<BeginBorrowInst>(incomingValue)->getOperand(), enclosingDefs,
|
|
visitedValues);
|
|
break;
|
|
}
|
|
case BorrowedValueKind::LoadBorrow:
|
|
case BorrowedValueKind::SILFunctionArgument:
|
|
// There is no enclosing def on this path.
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Given a reborrow, find the definitions of the enclosing borrow scopes. Each
|
|
// enclosing borrow scope is represented by one of the following cases, which
|
|
// refer to the example below:
|
|
//
|
|
// dominating owned value -> %value encloses %reborrow_1
|
|
// owned outer-adjacent phi -> %phi_3 encloses %reborrow_3
|
|
// dominating outer borrow introducer -> %outerBorrowB encloses %reborrow
|
|
// outer-adjacent reborrow -> %outerReborrow encloses %reborrow
|
|
//
|
|
// Recurse along the use-def phi web until a begin_borrow is reached. Then
|
|
// find all introducers of the begin_borrow's operand. At each level, find
|
|
// the outer adjacent phi, if one exists, otherwise return the most recently
|
|
// found dominating definition.
|
|
//
|
|
// If \p reborrow was already encountered because of a phi cycle, then no
|
|
// enclosingDefs are added.
|
|
//
|
|
// Example:
|
|
//
|
|
// %value = ...
|
|
// %borrow = begin_borrow %value
|
|
// br one(%borrow)
|
|
// one(%reborrow_1 : @guaranteed)
|
|
// br two(%value, %reborrow_1)
|
|
// two(%phi_2 : @owned, %reborrow_2 : @guaranteed)
|
|
// br three(%value, %reborrow_1)
|
|
// three(%phi_3 : @owned, %reborrow_3 : @guaranteed)
|
|
// end_borrow %reborrow_3
|
|
// destroy_value %phi_3
|
|
//
|
|
// recursivelyFindDefsOfReborrow(%reborrow_3) returns %phi_3 by
|
|
// computing enclosing defs (inner -> outer) in this order:
|
|
//
|
|
// %reborrow_1 -> %value
|
|
// %reborrow_2 -> %phi_2
|
|
// %reborrow_3 -> %phi_3
|
|
//
|
|
// Example:
|
|
//
|
|
// %outerBorrowA = begin_borrow
|
|
// %outerBorrowB = begin_borrow
|
|
// %struct = struct (%outerBorrowA, outerBorrowB)
|
|
// %borrow = begin_borrow %struct
|
|
// br one(%outerBorrowA, %borrow)
|
|
// one(%outerReborrow : @guaranteed, %reborrow : @guaranteed)
|
|
//
|
|
// recursivelyFindDefsOfReborrow(%reborrow) returns
|
|
// (%outerReborrow, %outerBorrowB).
|
|
//
|
|
void recursivelyFindDefsOfReborrow(SILPhiArgument *reborrow,
|
|
StackList<SILValue> &enclosingDefs) {
|
|
assert(enclosingDefs.empty());
|
|
LocalValueSetVector visitedDefs;
|
|
|
|
// phi cycles can be skipped. They cannot contribute any new enclosing defs.
|
|
if (!visitedPhis.insert(reborrow))
|
|
return;
|
|
|
|
SILBasicBlock *block = reborrow->getParent();
|
|
for (auto *pred : block->getPredecessorBlocks()) {
|
|
SILValue incomingValue = reborrow->getIncomingPhiValue(pred);
|
|
|
|
// Each phi operand requires a new enclosing def list. These values will
|
|
// be remapped to successor phis before adding them to the caller's
|
|
// enclosing def list. It may be necessary to revisit a value that was
|
|
// already visited by the caller before remapping to phis.
|
|
StackList<SILValue> enclosingPredDefs(function);
|
|
recursivelyFindDefsOfReborrowOperand(incomingValue, enclosingPredDefs);
|
|
findSuccessorDefsFromPredDefs(pred, enclosingPredDefs, enclosingDefs,
|
|
visitedDefs);
|
|
}
|
|
}
|
|
};
|
|
|
|
} // end namespace
|
|
|
|
bool swift::visitEnclosingDefs(SILValue value,
|
|
function_ref<bool(SILValue)> visitor) {
|
|
return FindEnclosingDefs(value->getFunction())
|
|
.visitEnclosingDefs(value, visitor);
|
|
}
|
|
|
|
bool swift::visitBorrowIntroducers(SILValue value,
|
|
function_ref<bool(SILValue)> visitor) {
|
|
return FindEnclosingDefs(value->getFunction())
|
|
.visitBorrowIntroducers(value, visitor);
|
|
}
|
|
|
|
void swift::visitTransitiveEndBorrows(
|
|
SILValue value,
|
|
function_ref<void(EndBorrowInst *)> visitEndBorrow) {
|
|
GraphNodeWorklist<SILValue, 4> worklist;
|
|
worklist.insert(value);
|
|
|
|
while (!worklist.empty()) {
|
|
auto val = worklist.pop();
|
|
for (auto *consumingUse : val->getConsumingUses()) {
|
|
auto *consumingUser = consumingUse->getUser();
|
|
if (auto *branch = dyn_cast<BranchInst>(consumingUser)) {
|
|
auto *succBlock = branch->getSingleSuccessorBlock();
|
|
auto *phiArg = cast<SILPhiArgument>(
|
|
succBlock->getArgument(consumingUse->getOperandNumber()));
|
|
worklist.insert(phiArg);
|
|
} else {
|
|
visitEndBorrow(cast<EndBorrowInst>(consumingUser));
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Whether the specified lexical begin_borrow instruction is nested.
|
|
///
|
|
/// A begin_borrow [lexical] is nested if the borrowed value's lifetime is
|
|
/// guaranteed by another lexical scope. That happens if:
|
|
/// - the value is a guaranteed argument to the function
|
|
/// - the value is itself a begin_borrow [lexical]
|
|
bool swift::isNestedLexicalBeginBorrow(BeginBorrowInst *bbi) {
|
|
assert(bbi->isLexical());
|
|
auto value = bbi->getOperand();
|
|
if (auto *outerBBI = dyn_cast<BeginBorrowInst>(value)) {
|
|
return outerBBI->isLexical();
|
|
}
|
|
if (auto *arg = dyn_cast<SILFunctionArgument>(value)) {
|
|
return arg->getOwnershipKind() == OwnershipKind::Guaranteed;
|
|
}
|
|
return false;
|
|
}
|