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SILGenLValue.cpp
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//===--- SILGenLValue.cpp - Constructs logical lvalues for SILGen ---------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Emission of l-value expressions and basic operations on them.
//
//===----------------------------------------------------------------------===//
#include "ASTVisitor.h"
#include "ArgumentScope.h"
#include "ArgumentSource.h"
#include "Conversion.h"
#include "ExecutorBreadcrumb.h"
#include "Initialization.h"
#include "LValue.h"
#include "ManagedValue.h"
#include "RValue.h"
#include "SILGen.h"
#include "SILGenFunction.h"
#include "Scope.h"
#include "swift/AST/DiagnosticsCommon.h"
#include "swift/AST/DiagnosticsSIL.h"
#include "swift/AST/GenericEnvironment.h"
#include "swift/AST/PropertyWrappers.h"
#include "swift/AST/TypeCheckRequests.h"
#include "swift/SIL/Consumption.h"
#include "swift/SIL/InstructionUtils.h"
#include "swift/SIL/MemAccessUtils.h"
#include "swift/SIL/PrettyStackTrace.h"
#include "swift/SIL/SILArgument.h"
#include "swift/SIL/SILInstruction.h"
#include "swift/SIL/SILUndef.h"
#include "swift/SIL/TypeLowering.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/raw_ostream.h"
using namespace swift;
using namespace Lowering;
//===----------------------------------------------------------------------===//
namespace {
struct LValueWritebackCleanup : Cleanup {
FormalEvaluationContext::stable_iterator Depth;
LValueWritebackCleanup() : Depth() {}
void emit(SILGenFunction &SGF, CleanupLocation loc,
ForUnwind_t forUnwind) override {
FullExpr scope(SGF.Cleanups, loc);
// TODO: honor forUnwind!
auto &evaluation = getEvaluation(SGF);
evaluation.performWriteback(SGF, /*isFinal*/ false);
}
void dump(SILGenFunction &) const override {
#ifndef NDEBUG
llvm::errs() << "LValueWritebackCleanup\n"
<< "State: " << getState() << " Depth: " << Depth.getDepth()
<< "\n";
#endif
}
private:
ExclusiveBorrowFormalAccess &getEvaluation(SILGenFunction &SGF) {
auto &evaluation = *SGF.FormalEvalContext.find(Depth);
assert(evaluation.getKind() == FormalAccess::Exclusive);
return static_cast<ExclusiveBorrowFormalAccess &>(evaluation);
}
};
} // end anonymous namespace
/// Push a writeback onto the current LValueWriteback stack.
static void pushWriteback(SILGenFunction &SGF,
SILLocation loc,
std::unique_ptr<LogicalPathComponent> &&comp,
ManagedValue base,
MaterializedLValue materialized) {
assert(SGF.isInFormalEvaluationScope());
// Push a cleanup to execute the writeback consistently.
auto &context = SGF.FormalEvalContext;
LValueWritebackCleanup &cleanup =
SGF.Cleanups.pushCleanup<LValueWritebackCleanup>();
CleanupHandle handle = SGF.Cleanups.getTopCleanup();
context.push<ExclusiveBorrowFormalAccess>(loc, std::move(comp), base,
materialized, handle);
cleanup.Depth = context.stable_begin();
}
static bool areCertainlyEqualArgumentLists(const ArgumentList *l1,
const ArgumentList *l2);
void ExclusiveBorrowFormalAccess::diagnoseConflict(
const ExclusiveBorrowFormalAccess &rhs,
SILGenFunction &SGF) const {
// If the two writebacks we're comparing are of different kinds (e.g.
// ownership conversion vs a computed property) then they aren't the
// same and thus cannot conflict.
if (component->getKind() != rhs.component->getKind())
return;
// If the lvalues don't have the same base value (possibly null), then
// they aren't the same. Note that this is the primary source of false
// negative for this diagnostic.
SILValue lhsBaseValue = base.getValue(), rhsBaseValue = rhs.base.getValue();
if (lhsBaseValue != rhsBaseValue &&
(!lhsBaseValue || !rhsBaseValue ||
!RValue::areObviouslySameValue(lhsBaseValue, rhsBaseValue))) {
return;
}
auto lhsStorage = component->getAccessStorage();
if (!lhsStorage) return;
auto rhsStorage = rhs.component->getAccessStorage();
if (!rhsStorage) return;
// If the decls match, then this could conflict.
if (lhsStorage->Storage != rhsStorage->Storage ||
!lhsStorage->Storage ||
lhsStorage->IsSuper != rhsStorage->IsSuper)
return;
assert((lhsStorage->Indices != nullptr) == (rhsStorage->Indices != nullptr));
auto storage = lhsStorage->Storage;
// If the decl is monomorphically a stored property, allow aliases.
// It could be overridden by a computed property in a subclass, but
// that's not likely enough to be worth the strictness here.
auto impl = storage->getImplInfo();
// TODO: Stored properties with didSet accessors that don't look at the
// oldValue could also be addressed.
if ((impl.getReadImpl() == ReadImplKind::Stored ||
impl.getReadImpl() == ReadImplKind::Address) &&
(impl.getWriteImpl() == WriteImplKind::Immutable ||
impl.getWriteImpl() == WriteImplKind::Stored ||
impl.getWriteImpl() == WriteImplKind::MutableAddress)) {
return;
}
// If the property is a generic requirement, allow aliases, because
// it may be conformed to using a stored property.
if (isa<ProtocolDecl>(storage->getDeclContext()))
return;
// If this is a simple property access, then we must have a conflict.
if (!lhsStorage->Indices) {
assert(isa<VarDecl>(storage));
SGF.SGM.diagnose(loc, diag::writeback_overlap_property,
storage->getBaseIdentifier())
.highlight(loc.getSourceRange());
SGF.SGM.diagnose(rhs.loc, diag::writebackoverlap_note)
.highlight(rhs.loc.getSourceRange());
return;
}
// Otherwise, it is a subscript, check the index values.
// If the indices are literally identical SILValue's, then there is
// clearly a conflict.
if (!lhsStorage->Indices->isObviouslyEqual(*rhsStorage->Indices)) {
// If the index value doesn't lower to literally the same SILValue's,
// do some fuzzy matching to catch the common case.
if (!lhsStorage->ArgListForDiagnostics ||
!rhsStorage->ArgListForDiagnostics ||
!areCertainlyEqualArgumentLists(lhsStorage->ArgListForDiagnostics,
rhsStorage->ArgListForDiagnostics))
return;
}
// The locations for the subscripts are almost certainly SubscriptExprs.
// If so, dig into them to produce better location info in the
// diagnostics and be able to do more precise analysis.
auto expr1 = loc.getAsASTNode<SubscriptExpr>();
auto expr2 = rhs.loc.getAsASTNode<SubscriptExpr>();
if (expr1 && expr2) {
SGF.SGM.diagnose(loc, diag::writeback_overlap_subscript)
.highlight(expr1->getBase()->getSourceRange());
SGF.SGM.diagnose(rhs.loc, diag::writebackoverlap_note)
.highlight(expr2->getBase()->getSourceRange());
} else {
SGF.SGM.diagnose(loc, diag::writeback_overlap_subscript)
.highlight(loc.getSourceRange());
SGF.SGM.diagnose(rhs.loc, diag::writebackoverlap_note)
.highlight(rhs.loc.getSourceRange());
}
}
//===----------------------------------------------------------------------===//
static CanType getSubstFormalRValueType(Expr *expr) {
return expr->getType()->getRValueType()->getCanonicalType();
}
static LValueTypeData getAbstractedTypeData(TypeExpansionContext context,
SILGenModule &SGM,
SGFAccessKind accessKind,
AbstractionPattern origFormalType,
CanType substFormalType) {
return {
accessKind, origFormalType, substFormalType,
SGM.Types.getLoweredRValueType(context, origFormalType, substFormalType)};
}
static LValueTypeData getLogicalStorageTypeData(TypeExpansionContext context,
SILGenModule &SGM,
SGFAccessKind accessKind,
CanType substFormalType) {
assert(!isa<ReferenceStorageType>(substFormalType));
AbstractionPattern origFormalType(
substFormalType.getReferenceStorageReferent());
return getAbstractedTypeData(context, SGM, accessKind, origFormalType,
substFormalType);
}
static LValueTypeData getPhysicalStorageTypeData(TypeExpansionContext context,
SILGenModule &SGM,
SGFAccessKind accessKind,
AbstractStorageDecl *storage,
SubstitutionMap subs,
CanType substFormalType) {
assert(!isa<ReferenceStorageType>(substFormalType));
auto origFormalType = SGM.Types.getAbstractionPattern(storage)
.getReferenceStorageReferentType()
.withSubstitutions(subs);
return getAbstractedTypeData(context, SGM, accessKind, origFormalType,
substFormalType);
}
static bool shouldUseUnsafeEnforcement(VarDecl *var) {
if (var->isDebuggerVar())
return true;
return false;
}
static bool hasExclusivityAttr(VarDecl *var, ExclusivityAttr::Mode mode) {
if (!var)
return false;
auto *exclAttr = var->getAttrs().getAttribute<ExclusivityAttr>();
return exclAttr && exclAttr->getMode() == mode;
}
llvm::Optional<SILAccessEnforcement>
SILGenFunction::getStaticEnforcement(VarDecl *var) {
if (var && shouldUseUnsafeEnforcement(var))
return SILAccessEnforcement::Unsafe;
return SILAccessEnforcement::Static;
}
llvm::Optional<SILAccessEnforcement>
SILGenFunction::getDynamicEnforcement(VarDecl *var) {
if (getOptions().EnforceExclusivityDynamic) {
if (var && shouldUseUnsafeEnforcement(var))
return SILAccessEnforcement::Unsafe;
if (hasExclusivityAttr(var, ExclusivityAttr::Unchecked))
return SILAccessEnforcement::Unsafe;
return SILAccessEnforcement::Dynamic;
} else if (hasExclusivityAttr(var, ExclusivityAttr::Checked)) {
return SILAccessEnforcement::Dynamic;
}
return llvm::None;
}
llvm::Optional<SILAccessEnforcement>
SILGenFunction::getUnknownEnforcement(VarDecl *var) {
if (var && shouldUseUnsafeEnforcement(var))
return SILAccessEnforcement::Unsafe;
return SILAccessEnforcement::Unknown;
}
/// SILGenLValue - An ASTVisitor for building logical lvalues.
class LLVM_LIBRARY_VISIBILITY SILGenLValue
: public Lowering::ExprVisitor<SILGenLValue, LValue,
SGFAccessKind, LValueOptions>
{
public:
SILGenFunction &SGF;
SILGenLValue(SILGenFunction &SGF) : SGF(SGF) {}
LValue visitRec(Expr *e, SGFAccessKind accessKind, LValueOptions options,
AbstractionPattern orig = AbstractionPattern::getInvalid());
/// Dummy handler to log unimplemented nodes.
LValue visitExpr(Expr *e, SGFAccessKind accessKind, LValueOptions options);
// Nodes that form the root of lvalue paths
LValue visitDiscardAssignmentExpr(DiscardAssignmentExpr *e,
SGFAccessKind accessKind,
LValueOptions options);
LValue visitDeclRefExpr(DeclRefExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitOpaqueValueExpr(OpaqueValueExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitPackElementExpr(PackElementExpr *e, SGFAccessKind accessKind,
LValueOptions options);
// Nodes that make up components of lvalue paths
LValue visitMemberRefExpr(MemberRefExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitSubscriptExpr(SubscriptExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitTupleElementExpr(TupleElementExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitForceValueExpr(ForceValueExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitBindOptionalExpr(BindOptionalExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitOpenExistentialExpr(OpenExistentialExpr *e,
SGFAccessKind accessKind,
LValueOptions options);
LValue visitKeyPathApplicationExpr(KeyPathApplicationExpr *e,
SGFAccessKind accessKind,
LValueOptions options);
LValue visitConsumeExpr(ConsumeExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitCopyExpr(CopyExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitABISafeConversionExpr(ABISafeConversionExpr *e,
SGFAccessKind accessKind,
LValueOptions options);
// Expressions that wrap lvalues
LValue visitLoadExpr(LoadExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitInOutExpr(InOutExpr *e, SGFAccessKind accessKind,
LValueOptions options);
LValue visitDotSyntaxBaseIgnoredExpr(DotSyntaxBaseIgnoredExpr *e,
SGFAccessKind accessKind,
LValueOptions options);
};
/// Read this component.
ManagedValue
LogicalPathComponent::projectForRead(SILGenFunction &SGF, SILLocation loc,
ManagedValue base,
SGFAccessKind accessKind) && {
assert(isReadAccess(accessKind));
const TypeLowering &RValueTL = SGF.getTypeLowering(getTypeOfRValue());
// If the access doesn't require us to make an owned address, don't
// force a materialization.
if (!isReadAccessResultAddress(accessKind)) {
auto rvalue = std::move(*this).get(SGF, loc, base, SGFContext());
return std::move(rvalue).getAsSingleValue(SGF, loc);
}
TemporaryInitializationPtr tempInit;
ManagedValue result;
RValue rvalue;
// If the RValue type has an openedExistential, then the RValue must be
// materialized before allocating a temporary for the RValue type. In that
// case, the RValue cannot be emitted directly into the temporary.
if (getTypeOfRValue().hasOpenedExistential()) {
// Emit a 'get'.
rvalue = std::move(*this).get(SGF, loc, base, SGFContext());
// Create a temporary, whose type may depend on the 'get'.
tempInit = SGF.emitFormalAccessTemporary(loc, RValueTL);
result = tempInit->getManagedAddress();
} else {
// Create a temporary for a static (non-dependent) RValue type.
tempInit = SGF.emitFormalAccessTemporary(loc, RValueTL);
result = tempInit->getManagedAddress();
// Emit a 'get' directly into the temporary.
rvalue = std::move(*this).get(SGF, loc, base, SGFContext(tempInit.get()));
}
// `this` is now dead.
// Force `value` into a temporary if is wasn't emitted there.
if (!rvalue.isInContext())
std::move(rvalue).forwardInto(SGF, loc, tempInit.get());
assert(result);
return result;
}
ManagedValue LogicalPathComponent::project(SILGenFunction &SGF,
SILLocation loc,
ManagedValue base) && {
auto accessKind = getAccessKind();
if (isReadAccess(accessKind))
return std::move(*this).projectForRead(SGF, loc, base, accessKind);
// AccessKind is Write or ReadWrite. We need to emit a get and set.
assert(SGF.isInFormalEvaluationScope() &&
"materializing l-value for modification without writeback scope");
// Clone anything else about the component that we might need in the
// writeback.
auto clonedComponent = clone(SGF, loc);
ManagedValue temp =
std::move(*this).projectForRead(SGF, loc, base,
SGFAccessKind::OwnedAddressRead);
if (SGF.getOptions().VerifyExclusivity) {
// Begin an access of the temporary. It is unenforced because enforcement
// isn't required for RValues.
SILValue accessAddress = UnenforcedFormalAccess::enter(
SGF, loc, temp.getValue(), SILAccessKind::Modify);
temp = std::move(temp).transform(accessAddress);
}
// Push a writeback for the temporary.
pushWriteback(SGF, loc, std::move(clonedComponent), base,
MaterializedLValue(temp));
return ManagedValue::forLValue(temp.getValue());
}
void LogicalPathComponent::writeback(SILGenFunction &SGF, SILLocation loc,
ManagedValue base,
MaterializedLValue materialized,
bool isFinal) {
assert(!materialized.callback &&
"unexpected materialized lvalue with callback!");
// Load the value from the temporary unless the type is address-only
// and this is the final use, in which case we can just consume the
// value as-is.
auto temporary = materialized.temporary;
assert(temporary.getType().isAddress());
auto &tempTL = SGF.getTypeLowering(temporary.getType());
if (!tempTL.isAddressOnly() || !isFinal ||
!SGF.silConv.useLoweredAddresses()) {
if (isFinal) temporary.forward(SGF);
temporary = SGF.emitLoad(loc, temporary.getValue(), tempTL,
SGFContext(), IsTake_t(isFinal));
}
RValue rvalue(SGF, loc, getSubstFormalType(), temporary);
// Don't consume cleanups on the base if this isn't final.
if (base && !isFinal) {
if (base.getOwnershipKind() == OwnershipKind::Guaranteed) {
base = ManagedValue::forBorrowedRValue(base.getValue());
} else {
base = ManagedValue::forUnmanagedOwnedValue(base.getValue());
}
}
// Clone the component if this isn't final.
std::unique_ptr<LogicalPathComponent> clonedComponent =
(isFinal ? nullptr : clone(SGF, loc));
LogicalPathComponent *component = (isFinal ? this : &*clonedComponent);
std::move(*component).set(SGF, loc, ArgumentSource(loc, std::move(rvalue)),
base);
}
InOutConversionScope::InOutConversionScope(SILGenFunction &SGF)
: SGF(SGF)
{
assert(SGF.isInFormalEvaluationScope()
&& "inout conversions should happen in writeback scopes");
assert(!SGF.InInOutConversionScope
&& "inout conversions should not be nested");
SGF.InInOutConversionScope = true;
}
InOutConversionScope::~InOutConversionScope() {
assert(SGF.InInOutConversionScope && "already exited conversion scope?!");
SGF.InInOutConversionScope = false;
}
void PathComponent::_anchor() {}
void PhysicalPathComponent::_anchor() {}
void PhysicalPathComponent::set(SILGenFunction &SGF, SILLocation loc,
ArgumentSource &&value, ManagedValue base) && {
auto finalDestAddr = std::move(*this).project(SGF, loc, base);
assert(finalDestAddr.getType().isAddress());
auto srcRValue = std::move(value).getAsRValue(SGF).ensurePlusOne(SGF, loc);
std::move(srcRValue).assignInto(SGF, loc, finalDestAddr.getValue());
}
void PathComponent::dump() const {
dump(llvm::errs());
}
/// Return the LValueTypeData for a SIL value with the given AST formal type.
static LValueTypeData getValueTypeData(SGFAccessKind accessKind,
CanType formalType, SILValue value) {
return {
accessKind,
AbstractionPattern(formalType),
formalType,
value->getType().getASTType(),
};
}
static LValueTypeData getValueTypeData(SILGenFunction &SGF,
SGFAccessKind accessKind, Expr *e) {
CanType formalType = getSubstFormalRValueType(e);
CanType loweredType = SGF.getLoweredType(formalType).getASTType();
return {
accessKind,
AbstractionPattern(formalType),
formalType,
loweredType
};
}
/// Given the address of an optional value, unsafely project out the
/// address of the value.
static ManagedValue getAddressOfOptionalValue(SILGenFunction &SGF,
SILLocation loc,
ManagedValue optAddr,
const LValueTypeData &valueTypeData) {
// Project out the 'Some' payload.
EnumElementDecl *someDecl = SGF.getASTContext().getOptionalSomeDecl();
// If the base is +1, we want to forward the cleanup.
bool hadCleanup = optAddr.hasCleanup();
// UncheckedTakeEnumDataAddr is safe to apply to Optional, because it is
// a single-payload enum. There will (currently) never be spare bits
// embedded in the payload.
SILValue valueAddr =
SGF.B.createUncheckedTakeEnumDataAddr(loc, optAddr.forward(SGF), someDecl,
SILType::getPrimitiveAddressType(
valueTypeData.TypeOfRValue));
// Return the value as +1 if the optional was +1.
if (hadCleanup) {
return SGF.emitManagedBufferWithCleanup(valueAddr);
} else {
return ManagedValue::forLValue(valueAddr);
}
}
namespace {
/// A helper class for creating writebacks associated with l-value
/// components that don't really need them.
class WritebackPseudoComponent : public LogicalPathComponent {
protected:
WritebackPseudoComponent(const LValueTypeData &typeData)
: LogicalPathComponent(typeData, WritebackPseudoKind) {}
public:
std::unique_ptr<LogicalPathComponent>
clone(SILGenFunction &SGF, SILLocation l) const override {
llvm_unreachable("called clone on pseudo-component");
}
RValue get(SILGenFunction &SGF, SILLocation loc,
ManagedValue base, SGFContext c) && override {
llvm_unreachable("called get on a pseudo-component");
}
void set(SILGenFunction &SGF, SILLocation loc,
ArgumentSource &&value, ManagedValue base) && override {
llvm_unreachable("called set on a pseudo-component");
}
ManagedValue project(SILGenFunction &SGF, SILLocation loc,
ManagedValue base) && override {
llvm_unreachable("called project on a pseudo-component");
}
llvm::Optional<AccessStorage> getAccessStorage() const override {
return llvm::None;
}
};
class EndAccessPseudoComponent : public WritebackPseudoComponent {
private:
ExecutorBreadcrumb ExecutorHop;
public:
EndAccessPseudoComponent(const LValueTypeData &typeData,
ExecutorBreadcrumb &&executorHop)
: WritebackPseudoComponent(typeData),
ExecutorHop(std::move(executorHop)) {}
private:
void writeback(SILGenFunction &SGF, SILLocation loc,
ManagedValue base,
MaterializedLValue materialized,
bool isFinal) override {
loc.markAutoGenerated();
assert(base.isLValue());
loc.markAutoGenerated();
SGF.B.createEndAccess(loc, base.getValue(), /*abort*/ false);
ExecutorHop.emit(SGF, loc);
}
void dump(raw_ostream &OS, unsigned indent) const override {
OS.indent(indent) << "EndAccessPseudoComponent\n";
}
};
} // end anonymous namespace
static SILValue enterAccessScope(SILGenFunction &SGF, SILLocation loc,
ManagedValue base, SILValue addr,
LValueTypeData typeData,
SGFAccessKind accessKind,
SILAccessEnforcement enforcement,
llvm::Optional<ActorIsolation> actorIso) {
auto silAccessKind = SILAccessKind::Modify;
if (isReadAccess(accessKind))
silAccessKind = SILAccessKind::Read;
else if (isConsumeAccess(accessKind))
silAccessKind = SILAccessKind::Deinit;
assert(SGF.isInFormalEvaluationScope() &&
"tried to enter access scope without a writeback scope!");
ExecutorBreadcrumb prevExecutor =
SGF.emitHopToTargetActor(loc, actorIso, base);
// Enter the access.
addr = SGF.B.createBeginAccess(loc, addr, silAccessKind, enforcement,
/*hasNoNestedConflict=*/false,
/*fromBuiltin=*/false);
// Push a writeback to end it.
auto accessedMV = ManagedValue::forLValue(addr);
std::unique_ptr<LogicalPathComponent> component(
new EndAccessPseudoComponent(typeData, std::move(prevExecutor)));
pushWriteback(SGF, loc, std::move(component), accessedMV,
MaterializedLValue());
return addr;
}
static ManagedValue enterAccessScope(SILGenFunction &SGF, SILLocation loc,
ManagedValue base, ManagedValue addr,
LValueTypeData typeData,
SGFAccessKind accessKind,
SILAccessEnforcement enforcement,
llvm::Optional<ActorIsolation> actorIso) {
return ManagedValue::forLValue(
enterAccessScope(SGF, loc, base, addr.getLValueAddress(), typeData,
accessKind, enforcement, actorIso));
}
// Find the base of the formal access at `address`. If the base requires an
// access marker, then create a begin_access on `address`. Return the
// address to be used for the access.
//
// FIXME: In order to generate more consistent and verifiable SIL patterns, or
// subobject projections, create the access on the base address and recreate the
// projection.
SILValue UnenforcedAccess::beginAccess(SILGenFunction &SGF, SILLocation loc,
SILValue address, SILAccessKind kind) {
if (!SGF.getOptions().VerifyExclusivity)
return address;
auto storage = AccessStorage::compute(address);
// Unsafe access may have invalid storage (e.g. a RawPointer).
if (storage && !isPossibleFormalAccessStorage(storage, &SGF.F))
return address;
auto BAI =
SGF.B.createBeginAccess(loc, address, kind, SILAccessEnforcement::Unsafe,
/*hasNoNestedConflict=*/false,
/*fromBuiltin=*/false);
beginAccessPtr = BeginAccessPtr(BAI, DeleterCheck());
return BAI;
}
void UnenforcedAccess::endAccess(SILGenFunction &SGF) {
emitEndAccess(SGF);
beginAccessPtr.release();
}
void UnenforcedAccess::emitEndAccess(SILGenFunction &SGF) {
if (!beginAccessPtr)
return;
SGF.B.createEndAccess(beginAccessPtr->getLoc(), beginAccessPtr.get(),
/*abort*/ false);
}
// Emit an end_access marker when executing a cleanup (on a side branch).
void UnenforcedFormalAccess::emitEndAccess(SILGenFunction &SGF) {
access.emitEndAccess(SGF);
}
// End the access when existing the FormalEvaluationScope.
void UnenforcedFormalAccess::finishImpl(SILGenFunction &SGF) {
access.endAccess(SGF);
}
namespace {
struct UnenforcedAccessCleanup : Cleanup {
FormalEvaluationContext::stable_iterator Depth;
UnenforcedAccessCleanup() : Depth() {}
void emit(SILGenFunction &SGF, CleanupLocation loc,
ForUnwind_t forUnwind) override {
auto &evaluation = *SGF.FormalEvalContext.find(Depth);
assert(evaluation.getKind() == FormalAccess::Unenforced);
auto &formalAccess = static_cast<UnenforcedFormalAccess &>(evaluation);
formalAccess.emitEndAccess(SGF);
}
void dump(SILGenFunction &) const override {
#ifndef NDEBUG
llvm::errs() << "UnenforcedAccessCleanup\n"
<< "State: " << getState() << " Depth: " << Depth.getDepth()
<< "\n";
#endif
}
};
} // end anonymous namespace
SILValue UnenforcedFormalAccess::enter(SILGenFunction &SGF, SILLocation loc,
SILValue address, SILAccessKind kind) {
assert(SGF.isInFormalEvaluationScope());
UnenforcedAccess access;
SILValue accessAddress = access.beginAccess(SGF, loc, address, kind);
if (!access.beginAccessPtr)
return address;
auto &cleanup = SGF.Cleanups.pushCleanup<UnenforcedAccessCleanup>();
CleanupHandle handle = SGF.Cleanups.getTopCleanup();
auto &context = SGF.FormalEvalContext;
context.push<UnenforcedFormalAccess>(loc, std::move(access), handle);
cleanup.Depth = context.stable_begin();
return accessAddress;
}
static void copyBorrowedYieldsIntoTemporary(SILGenFunction &SGF,
SILLocation loc,
ArrayRef<ManagedValue> &yields,
AbstractionPattern origFormalType,
CanType substFormalType,
Initialization *init) {
if (!origFormalType.isTuple()) {
auto value = yields.front();
yields = yields.drop_front();
init->copyOrInitValueInto(SGF, loc, value, /*isInit*/ false);
init->finishInitialization(SGF);
return;
}
assert(init->canSplitIntoTupleElements());
SmallVector<InitializationPtr, 4> scratch;
auto eltInits =
init->splitIntoTupleElements(SGF, loc, substFormalType, scratch);
for (size_t i : indices(eltInits)) {
auto origEltType = origFormalType.getTupleElementType(i);
auto substEltType = cast<TupleType>(substFormalType).getElementType(i);
copyBorrowedYieldsIntoTemporary(SGF, loc, yields, origEltType,
substEltType, eltInits[i].get());
}
init->finishInitialization(SGF);
}
namespace {
class RefElementComponent : public PhysicalPathComponent {
VarDecl *Field;
SILType SubstFieldType;
bool IsNonAccessing;
public:
RefElementComponent(VarDecl *field, LValueOptions options,
SILType substFieldType, LValueTypeData typeData,
llvm::Optional<ActorIsolation> actorIso)
: PhysicalPathComponent(typeData, RefElementKind, actorIso),
Field(field), SubstFieldType(substFieldType),
IsNonAccessing(options.IsNonAccessing) {}
virtual bool isLoadingPure() const override { return true; }
VarDecl *getField() const { return Field; }
ManagedValue project(SILGenFunction &SGF, SILLocation loc,
ManagedValue base) && override {
assert(base.getType().hasReferenceSemantics() &&
"base for ref element component must be a reference type");
// Borrow the ref element addr using formal access. If we need the ref
// element addr, we will load it in this expression.
if (base.getType().isAddress()) {
base = SGF.B.createFormalAccessLoadBorrow(loc, base);
} else {
base = base.formalAccessBorrow(SGF, loc);
}
SILValue result =
SGF.B.createRefElementAddr(loc, base.getUnmanagedValue(),
Field, SubstFieldType);
// Avoid emitting access markers completely for non-accesses or immutable
// declarations. Access marker verification is aware of these cases.
if (!IsNonAccessing && !Field->isLet()) {
if (auto enforcement = SGF.getDynamicEnforcement(Field)) {
result = enterAccessScope(SGF, loc, base, result, getTypeData(),
getAccessKind(), *enforcement,
takeActorIsolation());
}
}
// If we have a move only type, add a marker.
//
// NOTE: We purposely do this on the access itself to ensure that when we
// hoist destroy_addr, they stay within the access scope.
if (result->getType().isMoveOnly()) {
auto checkKind = MarkUnresolvedNonCopyableValueInst::CheckKind::
AssignableButNotConsumable;
if (isReadAccess(getAccessKind())) {
// Add a mark_unresolved_non_copyable_value [no_consume_or_assign].
checkKind =
MarkUnresolvedNonCopyableValueInst::CheckKind::NoConsumeOrAssign;
}
result = SGF.B.createMarkUnresolvedNonCopyableValueInst(loc, result,
checkKind);
}
return ManagedValue::forLValue(result);
}
void dump(raw_ostream &OS, unsigned indent) const override {
OS.indent(indent) << "RefElementComponent(" << Field->getName() << ")\n";
}
};
class TupleElementComponent : public PhysicalPathComponent {
unsigned ElementIndex;
public:
TupleElementComponent(unsigned elementIndex, LValueTypeData typeData)
: PhysicalPathComponent(typeData, TupleElementKind,
/*actorIsolation=*/llvm::None),
ElementIndex(elementIndex) {}
virtual bool isLoadingPure() const override { return true; }
ManagedValue project(SILGenFunction &SGF, SILLocation loc,
ManagedValue base) && override {
assert(base && "invalid value for element base");
if (base.getType().isObject()) {
return SGF.B.createTupleExtract(loc, base, ElementIndex);
}
// TODO: if the base is +1, break apart its cleanup.
auto Res = SGF.B.createTupleElementAddr(loc, base.getValue(),
ElementIndex,
getTypeOfRValue().getAddressType());
return ManagedValue::forLValue(Res);
}
void dump(raw_ostream &OS, unsigned indent) const override {
OS.indent(indent) << "TupleElementComponent(" << ElementIndex << ")\n";
}
};
class StructElementComponent : public PhysicalPathComponent {
VarDecl *Field;
SILType SubstFieldType;
public:
StructElementComponent(VarDecl *field, SILType substFieldType,
LValueTypeData typeData,
llvm::Optional<ActorIsolation> actorIso)
: PhysicalPathComponent(typeData, StructElementKind, actorIso),
Field(field), SubstFieldType(substFieldType) {}
virtual bool isLoadingPure() const override { return true; }
ManagedValue project(SILGenFunction &SGF, SILLocation loc,
ManagedValue base) && override {
assert(base && "invalid value for element base");
if (base.getType().isObject()) {
return SGF.B.createStructExtract(loc, base, Field);
}
// If we have a moveonlywrapped type, unwrap it. The reason why is that
// any fields that we access we want to be treated as copyable.
if (base.getType().isMoveOnlyWrapped())
base = ManagedValue::forLValue(
SGF.B.createMoveOnlyWrapperToCopyableAddr(loc, base.getValue()));
// TODO: if the base is +1, break apart its cleanup.
auto Res = SGF.B.createStructElementAddr(loc, base.getValue(),
Field, SubstFieldType);
if (!Field->getPointerAuthQualifier().isPresent() ||
!SGF.getOptions().EnableImportPtrauthFieldFunctionPointers) {
return ManagedValue::forLValue(Res);
}
auto beginAccess =
enterAccessScope(SGF, loc, base, Res, getTypeData(), getAccessKind(),
SILAccessEnforcement::Signed, takeActorIsolation());
return ManagedValue::forLValue(beginAccess);
}
void dump(raw_ostream &OS, unsigned indent) const override {
OS.indent(indent) << "StructElementComponent("
<< Field->getName() << ")\n";
}
};
/// A physical path component which force-projects the address of
/// the value of an optional l-value.
class ForceOptionalObjectComponent : public PhysicalPathComponent {
bool isImplicitUnwrap;
public:
ForceOptionalObjectComponent(LValueTypeData typeData, bool isImplicitUnwrap)
: PhysicalPathComponent(typeData, OptionalObjectKind,
/*actorIsolation=*/llvm::None),
isImplicitUnwrap(isImplicitUnwrap) {}
ManagedValue project(SILGenFunction &SGF, SILLocation loc,
ManagedValue base) && override {
// Assert that the optional value is present and return the projected out
// payload.
return SGF.emitPreconditionOptionalHasValue(loc, base, isImplicitUnwrap);
}
void dump(raw_ostream &OS, unsigned indent) const override {
OS.indent(indent) << "ForceOptionalObjectComponent(" << isImplicitUnwrap << ")\n";
}
};
/// A physical path component which projects out an opened archetype
/// from an existential.
class OpenOpaqueExistentialComponent : public PhysicalPathComponent {
public:
OpenOpaqueExistentialComponent(CanArchetypeType openedArchetype,
LValueTypeData typeData)
: PhysicalPathComponent(typeData, OpenOpaqueExistentialKind,
/*actorIsolation=*/llvm::None) {
assert(getSubstFormalType() == openedArchetype);
}
virtual bool isLoadingPure() const override { return true; }
ManagedValue project(SILGenFunction &SGF, SILLocation loc,
ManagedValue base) && override {
assert(base.getType().isExistentialType() &&
"base for open existential component must be an existential");
assert((base.getType().isAddress() ||
base.getType().getPreferredExistentialRepresentation() ==
ExistentialRepresentation::Boxed ||
!SGF.useLoweredAddresses()) &&
"base value of open-existential component was not an address or a "
"boxed existential?");
SILValue addr;
auto rep = base.getType().getPreferredExistentialRepresentation();
switch (rep) {
case ExistentialRepresentation::Opaque:
if (!base.getValue()->getType().isAddress()) {
assert(!SGF.useLoweredAddresses());
auto borrow =
SGF.B.createBeginBorrow(loc, base.getValue(), /*isLexical=*/false,
/*hasPointerEscape=*/false);
auto value =
SGF.B.createOpenExistentialValue(loc, borrow, getTypeOfRValue());
SGF.Cleanups.pushCleanup<EndBorrowCleanup>(borrow);
return ManagedValue::forForwardedRValue(SGF, value);
} else {
addr = SGF.B.createOpenExistentialAddr(
loc, base.getValue(), getTypeOfRValue().getAddressType(),
getOpenedExistentialAccessFor(
getFormalAccessKind(getAccessKind())));
}
break;
case ExistentialRepresentation::Boxed: {
ManagedValue error;
if (base.getType().isObject()) {
error = base;
} else {
auto &TL = SGF.getTypeLowering(base.getType());
error = SGF.emitLoad(loc, base.getValue(), TL,
SGFContext(), IsNotTake);
// Error comes back to us with a +1 cleanup that is not a formal
// access cleanup. We need it to be that so that the load nests
// properly with other lvalue scoped things like the borrow below.
error = SGF.emitFormalAccessManagedRValueWithCleanup(
loc, error.forward(SGF));
}
SILType addrType = getTypeOfRValue().getAddressType();
addr = SGF.B.createOpenExistentialBox(loc, error, addrType).getValue();