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swift-mirror/lib/SIL/InstructionUtils.cpp

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16 KiB
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//===--- InstructionUtils.cpp - Utilities for SIL instructions ------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "sil-inst-utils"
#include "swift/SIL/InstructionUtils.h"
#include "swift/Basic/NullablePtr.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/SIL/Projection.h"
#include "swift/SIL/SILArgument.h"
#include "swift/SIL/SILBasicBlock.h"
#include "swift/SIL/SILVisitor.h"
using namespace swift;
/// Strip off casts/indexing insts/address projections from V until there is
/// nothing left to strip.
/// FIXME: Why don't we strip projections after stripping indexes?
SILValue swift::getUnderlyingObject(SILValue V) {
while (true) {
SILValue V2 = stripIndexingInsts(stripAddressProjections(stripCasts(V)));
if (V2 == V)
return V2;
V = V2;
}
}
SILValue swift::getUnderlyingAddressRoot(SILValue V) {
while (true) {
SILValue V2 = stripIndexingInsts(stripCasts(V));
switch (V2->getKind()) {
case ValueKind::StructElementAddrInst:
case ValueKind::TupleElementAddrInst:
case ValueKind::UncheckedTakeEnumDataAddrInst:
V2 = cast<SILInstruction>(V2)->getOperand(0);
break;
default:
break;
}
if (V2 == V)
return V2;
V = V2;
}
}
SILValue swift::getUnderlyingObjectStopAtMarkDependence(SILValue V) {
while (true) {
SILValue V2 = stripIndexingInsts(stripAddressProjections(stripCastsWithoutMarkDependence(V)));
if (V2 == V)
return V2;
V = V2;
}
}
static bool isRCIdentityPreservingCast(ValueKind Kind) {
switch (Kind) {
case ValueKind::UpcastInst:
case ValueKind::UncheckedRefCastInst:
case ValueKind::UncheckedRefCastAddrInst:
case ValueKind::UnconditionalCheckedCastInst:
case ValueKind::UnconditionalCheckedCastOpaqueInst:
case ValueKind::RefToBridgeObjectInst:
case ValueKind::BridgeObjectToRefInst:
return true;
default:
return false;
}
}
/// Return the underlying SILValue after stripping off identity SILArguments if
/// we belong to a BB with one predecessor.
SILValue swift::stripSinglePredecessorArgs(SILValue V) {
while (true) {
auto *A = dyn_cast<SILArgument>(V);
if (!A)
return V;
SILBasicBlock *BB = A->getParent();
// First try and grab the single predecessor of our parent BB. If we don't
// have one, bail.
SILBasicBlock *Pred = BB->getSinglePredecessorBlock();
if (!Pred)
return V;
// Then grab the terminator of Pred...
TermInst *PredTI = Pred->getTerminator();
// And attempt to find our matching argument.
//
// *NOTE* We can only strip things here if we know that there is no semantic
// change in terms of upcasts/downcasts/enum extraction since this is used
// by other routines here. This means that we can only look through
// cond_br/br.
//
// For instance, routines that use stripUpcasts() do not want to strip off a
// downcast that results from checked_cast_br.
if (auto *BI = dyn_cast<BranchInst>(PredTI)) {
V = BI->getArg(A->getIndex());
continue;
}
if (auto *CBI = dyn_cast<CondBranchInst>(PredTI)) {
if (SILValue Arg = CBI->getArgForDestBB(BB, A)) {
V = Arg;
continue;
}
}
return V;
}
}
SILValue swift::stripCastsWithoutMarkDependence(SILValue V) {
while (true) {
V = stripSinglePredecessorArgs(V);
auto K = V->getKind();
if (isRCIdentityPreservingCast(K) ||
K == ValueKind::UncheckedTrivialBitCastInst) {
V = cast<SILInstruction>(V)->getOperand(0);
continue;
}
return V;
}
}
SILValue swift::stripCasts(SILValue V) {
while (true) {
V = stripSinglePredecessorArgs(V);
auto K = V->getKind();
if (isRCIdentityPreservingCast(K)
|| K == ValueKind::UncheckedTrivialBitCastInst
|| K == ValueKind::MarkDependenceInst) {
V = cast<SILInstruction>(V)->getOperand(0);
continue;
}
return V;
}
}
SILValue swift::stripUpCasts(SILValue V) {
assert(V->getType().isClassOrClassMetatype() &&
"Expected class or class metatype!");
V = stripSinglePredecessorArgs(V);
while (isa<UpcastInst>(V))
V = stripSinglePredecessorArgs(cast<UpcastInst>(V)->getOperand());
return V;
}
SILValue swift::stripClassCasts(SILValue V) {
while (true) {
if (auto *UI = dyn_cast<UpcastInst>(V)) {
V = UI->getOperand();
continue;
}
if (auto *UCCI = dyn_cast<UnconditionalCheckedCastInst>(V)) {
V = UCCI->getOperand();
continue;
}
return V;
}
}
SILValue swift::stripAddressProjections(SILValue V) {
while (true) {
V = stripSinglePredecessorArgs(V);
if (!Projection::isAddressProjection(V))
return V;
V = cast<SILInstruction>(V)->getOperand(0);
}
}
SILValue swift::stripUnaryAddressProjections(SILValue V) {
while (true) {
V = stripSinglePredecessorArgs(V);
if (!Projection::isAddressProjection(V))
return V;
auto *Inst = cast<SILInstruction>(V);
if (Inst->getNumOperands() > 1)
return V;
V = Inst->getOperand(0);
}
}
SILValue swift::stripValueProjections(SILValue V) {
while (true) {
V = stripSinglePredecessorArgs(V);
if (!Projection::isObjectProjection(V))
return V;
V = cast<SILInstruction>(V)->getOperand(0);
}
}
SILValue swift::stripIndexingInsts(SILValue V) {
while (true) {
if (!isa<IndexingInst>(V))
return V;
V = cast<IndexingInst>(V)->getBase();
}
}
SILValue swift::stripExpectIntrinsic(SILValue V) {
auto *BI = dyn_cast<BuiltinInst>(V);
if (!BI)
return V;
if (BI->getIntrinsicInfo().ID != llvm::Intrinsic::expect)
return V;
return BI->getArguments()[0];
}
void ConformanceCollector::scanType(Type type) {
type = type->getCanonicalType();
if (Visited.count(type.getPointer()) != 0)
return;
// Look for all possible metatypes and conformances which are used in type.
type.visit([this](Type SubType) {
if (NominalTypeDecl *NT = SubType->getNominalOrBoundGenericNominal()) {
if (Visited.count(SubType.getPointer()) == 0) {
if (Visited.count(NT) == 0) {
EscapingMetaTypes.push_back(NT);
Visited.insert(NT);
}
// Also inserts the type passed to scanType().
Visited.insert(SubType.getPointer());
auto substs = SubType->gatherAllSubstitutions(M.getSwiftModule(),
nullptr);
scanSubsts(substs);
}
}
});
}
void ConformanceCollector::scanSubsts(SubstitutionList substs) {
for (const Substitution &subst : substs) {
scanConformances(subst.getConformances());
scanType(subst.getReplacement());
}
}
void ConformanceCollector::scanConformance(ProtocolConformance *C) {
if (!C || Visited.count(C) != 0)
return;
Visited.insert(C);
Conformances.push_back(C);
switch (C->getKind()) {
case ProtocolConformanceKind::Normal:
break;
case ProtocolConformanceKind::Inherited:
scanConformance(cast<InheritedProtocolConformance>(C)->
getInheritedConformance());
break;
case ProtocolConformanceKind::Specialized: {
auto *SpecC = cast<SpecializedProtocolConformance>(C);
scanConformance(SpecC->getGenericConformance());
scanSubsts(SpecC->getGenericSubstitutions());
break;
}
}
SILWitnessTable *WT = M.lookUpWitnessTable(C, /*deserializeLazily*/ false);
if (!WT)
return;
for (const SILWitnessTable::Entry &entry : WT->getEntries()) {
switch (entry.getKind()) {
case SILWitnessTable::AssociatedTypeProtocol:
scanConformance(entry.getAssociatedTypeProtocolWitness().Witness);
break;
case SILWitnessTable::BaseProtocol:
scanConformance(entry.getBaseProtocolWitness().Witness);
break;
case SILWitnessTable::AssociatedType:
scanType(entry.getAssociatedTypeWitness().Witness);
break;
case SILWitnessTable::Method:
case SILWitnessTable::Invalid:
case SILWitnessTable::MissingOptional:
break;
}
}
}
void ConformanceCollector::scanConformances(
ArrayRef<ProtocolConformanceRef> CRefs) {
for (ProtocolConformanceRef CRef : CRefs) {
scanConformance(CRef);
}
}
void ConformanceCollector::collect(swift::SILInstruction *I) {
switch (I->getKind()) {
case ValueKind::InitExistentialAddrInst: {
auto *IEI = cast<InitExistentialAddrInst>(I);
for (ProtocolConformanceRef CRef : IEI->getConformances()) {
if (CRef.isConcrete()) {
scanConformance(CRef.getConcrete()->getRootNormalConformance());
}
}
scanType(IEI->getFormalConcreteType());
break;
}
case ValueKind::InitExistentialRefInst:
scanConformances(cast<InitExistentialRefInst>(I)->getConformances());
break;
case ValueKind::InitExistentialMetatypeInst:
scanConformances(cast<InitExistentialMetatypeInst>(I)->getConformances());
break;
case ValueKind::WitnessMethodInst:
scanConformance(cast<WitnessMethodInst>(I)->getConformance());
break;
case ValueKind::SuperMethodInst: {
SILType InstanceTy = cast<SuperMethodInst>(I)->getOperand()->getType();
if (auto MTy = dyn_cast<MetatypeType>(InstanceTy.getSwiftRValueType()))
InstanceTy = SILType::getPrimitiveObjectType(MTy.getInstanceType());
if (SILType SuperTy = InstanceTy.getSuperclass(/*resolver=*/nullptr))
scanType(SuperTy.getSwiftRValueType());
break;
}
case ValueKind::AllocBoxInst: {
CanSILBoxType BTy = cast<AllocBoxInst>(I)->getBoxType();
size_t NumFields = BTy->getLayout()->getFields().size();
for (size_t Idx = 0; Idx < NumFields; ++Idx) {
scanType(BTy->getFieldLoweredType(M, Idx));
}
scanType(I->getType().getSwiftRValueType());
break;
}
case ValueKind::AllocExistentialBoxInst: {
auto *AEBI = cast<AllocExistentialBoxInst>(I);
scanType(AEBI->getFormalConcreteType());
scanConformances(AEBI->getConformances());
break;
}
case ValueKind::DeallocExistentialBoxInst:
scanType(cast<DeallocExistentialBoxInst>(I)->getConcreteType());
break;
case ValueKind::AllocRefInst:
case ValueKind::AllocRefDynamicInst:
case ValueKind::MetatypeInst:
case ValueKind::UnconditionalCheckedCastInst:
case ValueKind::UnconditionalCheckedCastOpaqueInst:
scanType(I->getType().getSwiftRValueType());
break;
case ValueKind::AllocStackInst: {
Type Ty = I->getType().getSwiftRValueType();
if (Ty->hasArchetype())
scanType(Ty);
break;
}
case ValueKind::CheckedCastAddrBranchInst: {
auto *CCABI = cast<CheckedCastAddrBranchInst>(I);
scanType(CCABI->getSourceType());
scanType(CCABI->getTargetType());
break;
}
case ValueKind::UnconditionalCheckedCastAddrInst: {
auto *UCCAI = cast<UnconditionalCheckedCastAddrInst>(I);
scanType(UCCAI->getSourceType());
scanType(UCCAI->getTargetType());
break;
}
case ValueKind::CheckedCastBranchInst:
scanType(cast<CheckedCastBranchInst>(I)->getCastType().
getSwiftRValueType());
break;
case ValueKind::ValueMetatypeInst: {
auto *VMTI = cast<ValueMetatypeInst>(I);
scanType(VMTI->getOperand()->getType().getSwiftRValueType());
break;
}
case ValueKind::DestroyAddrInst:
case ValueKind::StructElementAddrInst:
case ValueKind::TupleElementAddrInst:
case ValueKind::InjectEnumAddrInst:
case ValueKind::SwitchEnumAddrInst:
case ValueKind::SelectEnumAddrInst:
case ValueKind::IndexAddrInst:
case ValueKind::RefElementAddrInst:
case ValueKind::CopyAddrInst: {
Type Ty = I->getOperand(0)->getType().getSwiftRValueType();
if (Ty->hasArchetype())
scanType(Ty);
break;
}
default:
if (ApplySite AS = ApplySite::isa(I)) {
auto substs = AS.getSubstitutions();
scanSubsts(substs);
CanSILFunctionType OrigFnTy = AS.getOrigCalleeType();
CanSILFunctionType SubstFnTy = AS.getSubstCalleeType();
scanFuncParams(OrigFnTy->getParameters(), SubstFnTy->getParameters());
scanFuncParams(OrigFnTy->getResults(), SubstFnTy->getResults());
if (OrigFnTy->getRepresentation() ==
SILFunctionType::Representation::WitnessMethod) {
// The self parameter of a witness method is always generic.
scanType(OrigFnTy->getSelfInstanceType());
}
}
break;
}
}
void ConformanceCollector::collect(SILWitnessTable *WT) {
scanConformance(WT->getConformance());
}
void ConformanceCollector::dump() {
llvm::errs() << "ConformanceCollector:\n";
for (const ProtocolConformance *C : Conformances) {
C->dump();
}
}
namespace {
enum class OwnershipQualifiedKind {
NotApplicable,
Qualified,
Unqualified,
};
struct OwnershipQualifiedKindVisitor : SILInstructionVisitor<OwnershipQualifiedKindVisitor, OwnershipQualifiedKind> {
OwnershipQualifiedKind visitValueBase(ValueBase *V) {
return OwnershipQualifiedKind::NotApplicable;
}
#define QUALIFIED_INST(CLASS) \
OwnershipQualifiedKind visit ## CLASS(CLASS *I) { \
return OwnershipQualifiedKind::Qualified; \
}
QUALIFIED_INST(EndBorrowInst)
QUALIFIED_INST(LoadBorrowInst)
QUALIFIED_INST(CopyValueInst)
QUALIFIED_INST(CopyUnownedValueInst)
QUALIFIED_INST(DestroyValueInst)
#undef QUALIFIED_INST
OwnershipQualifiedKind visitLoadInst(LoadInst *LI) {
if (LI->getOwnershipQualifier() == LoadOwnershipQualifier::Unqualified)
return OwnershipQualifiedKind::Unqualified;
return OwnershipQualifiedKind::Qualified;
}
OwnershipQualifiedKind visitStoreInst(StoreInst *SI) {
if (SI->getOwnershipQualifier() == StoreOwnershipQualifier::Unqualified)
return OwnershipQualifiedKind::Unqualified;
return OwnershipQualifiedKind::Qualified;
}
};
} // end anonymous namespace
bool FunctionOwnershipEvaluator::evaluate(SILInstruction *I) {
assert(I->getFunction() == F.get() && "Can not evaluate function ownership "
"implications of an instruction that "
"does not belong to the instruction "
"that we are evaluating");
switch (OwnershipQualifiedKindVisitor().visit(I)) {
case OwnershipQualifiedKind::Unqualified: {
// If we already know that the function has unqualified ownership, just
// return early.
if (!F.get()->hasQualifiedOwnership())
return true;
// Ok, so we know at this point that we have qualified ownership. If we have
// seen any instructions with qualified ownership, we have an error since
// the function mixes qualified and unqualified instructions.
if (HasOwnershipQualifiedInstruction)
return false;
// Otherwise, set the function to have unqualified ownership. This will
// ensure that no more Qualified instructions can be added to the given
// function.
F.get()->setUnqualifiedOwnership();
return true;
}
case OwnershipQualifiedKind::Qualified: {
// First check if our function has unqualified ownership. If we already do
// have unqualified ownership, then we know that we have already seen an
// unqualified ownership instruction. This means the function has both
// qualified and unqualified instructions. =><=.
if (!F.get()->hasQualifiedOwnership())
return false;
// Ok, at this point we know that we are still qualified. Since functions
// start as qualified, we need to set the HasOwnershipQualifiedInstructions
// so we do not need to look back through the function if we see an
// unqualified instruction later on.
HasOwnershipQualifiedInstruction = true;
return true;
}
case OwnershipQualifiedKind::NotApplicable: {
// Not Applicable instr
return true;
}
}
llvm_unreachable("Unhandled OwnershipQualifiedKind in switch.");
}