Files
swift-mirror/lib/SILGen/SILGenConcurrency.cpp
Allan Shortlidge d0f63a0753 AST: Split Availability.h into multiple headers.
Put AvailabilityRange into its own header with very few dependencies so that it
can be included freely in other headers that need to use it as a complete type.

NFC.
2025-01-03 18:36:04 -08:00

871 lines
33 KiB
C++

//===--- SILGenConcurrency.cpp - Concurrency-specific SILGen --------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2024 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
//
//===----------------------------------------------------------------------===//
#include "ArgumentSource.h"
#include "ExecutorBreadcrumb.h"
#include "RValue.h"
#include "Scope.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/AvailabilityInference.h"
#include "swift/AST/ConformanceLookup.h"
#include "swift/AST/DistributedDecl.h"
#include "swift/AST/ProtocolConformance.h"
#include "swift/Basic/Assertions.h"
#include "swift/Basic/Range.h"
using namespace swift;
using namespace Lowering;
static void setExpectedExecutorForGeneric(SILGenFunction &SGF) {
auto loc = RegularLocation::getAutoGeneratedLocation(SGF.F.getLocation());
SGF.ExpectedExecutor.set(SGF.emitGenericExecutor(loc));
}
static void setExpectedExecutorForGlobalActor(SILGenFunction &SGF,
Type globalActor) {
SGF.ExpectedExecutor.set(SGF.emitLoadGlobalActorExecutor(globalActor));
}
static void setExpectedExecutorForLocalVar(SILGenFunction &SGF,
VarDecl *var) {
auto loc = RegularLocation::getAutoGeneratedLocation(SGF.F.getLocation());
Type actorType = var->getTypeInContext();
RValue actorInstanceRV = SGF.emitRValueForDecl(
loc, var, actorType, AccessSemantics::Ordinary);
ManagedValue actorInstance =
std::move(actorInstanceRV).getScalarValue();
SGF.ExpectedExecutor.set(SGF.emitLoadActorExecutor(loc, actorInstance));
}
static void
setExpectedExecutorForParameterIsolation(SILGenFunction &SGF,
ActorIsolation actorIsolation) {
auto loc = RegularLocation::getAutoGeneratedLocation(SGF.F.getLocation());
if (actorIsolation.isActorInstanceIsolated()) {
if (actorIsolation.isActorInstanceForSelfParameter()) {
ManagedValue selfMV;
auto selfArg = SGF.F.getSelfArgument();
if (selfArg->getOwnershipKind() == OwnershipKind::Guaranteed) {
selfMV = ManagedValue::forBorrowedRValue(selfArg);
} else {
selfMV = ManagedValue::forUnmanagedOwnedValue(selfArg);
}
SGF.ExpectedExecutor.set(SGF.emitLoadActorExecutor(loc, selfMV));
return;
}
// See if our actorIsolation actually has an actor instance associated with
// it.
if (auto param = actorIsolation.getActorInstance()) {
return setExpectedExecutorForLocalVar(SGF, param);
}
}
// If we have caller isolation inheriting... just grab from our isolated
// argument.
if (actorIsolation.getKind() == ActorIsolation::CallerIsolationInheriting) {
if (auto *isolatedArg = SGF.F.maybeGetIsolatedArgument()) {
ManagedValue isolatedMV;
if (isolatedArg->getOwnershipKind() == OwnershipKind::Guaranteed) {
isolatedMV = ManagedValue::forBorrowedRValue(isolatedArg);
} else {
isolatedMV = ManagedValue::forUnmanagedOwnedValue(isolatedArg);
}
SGF.ExpectedExecutor.set(SGF.emitLoadActorExecutor(loc, isolatedMV));
return;
}
}
llvm_unreachable("Unhandled case?!");
}
void SILGenFunction::emitExpectedExecutorProlog() {
// Whether the given declaration context is nested within an actor's
// destructor.
auto isInActorDestructor = [](DeclContext *dc) {
while (!dc->isModuleScopeContext() && !dc->isTypeContext()) {
if (auto destructor = dyn_cast<DestructorDecl>(dc)) {
switch (getActorIsolation(destructor)) {
case ActorIsolation::ActorInstance:
return true;
case ActorIsolation::GlobalActor:
// Global-actor-isolated types should likely have deinits that
// are not themselves actor-isolated, yet still have access to
// the instance properties of the class.
return false;
case ActorIsolation::Nonisolated:
case ActorIsolation::NonisolatedUnsafe:
case ActorIsolation::Unspecified:
case ActorIsolation::CallerIsolationInheriting:
return false;
case ActorIsolation::Erased:
llvm_unreachable("deinit cannot have erased isolation");
}
}
dc = dc->getParent();
}
return false;
};
// Initialize ExpectedExecutor if:
// - this function is async or
// - this function is sync and isolated to an actor, and we want to
// dynamically check that we're on the right executor.
//
// Actor destructors are isolated in the sense that we now have a
// unique reference to the actor, but we probably aren't running on
// the actor's executor, so we cannot safely do this check.
//
// Defer bodies are always called synchronously within their enclosing
// function, so the check is unnecessary; in addition, we cannot
// necessarily perform the check because the defer may not have
// captured the isolated parameter of the enclosing function.
bool wantDataRaceChecks = [&] {
if (F.isAsync() || F.isDefer())
return false;
if (getOptions().EnableActorDataRaceChecks &&
!isInActorDestructor(FunctionDC))
return true;
if (getASTContext().LangOpts.isDynamicActorIsolationCheckingEnabled()) {
if (auto closure = dyn_cast<ClosureExpr>(FunctionDC))
if (closure->requiresDynamicIsolationChecking())
return true;
}
return false;
}();
// FIXME: Avoid loading and checking the expected executor if concurrency is
// unavailable. This is specifically relevant for MainActor isolated contexts,
// which are allowed to be available on OSes where concurrency is not
// available. rdar://106827064
if (auto *funcDecl =
dyn_cast_or_null<AbstractFunctionDecl>(FunctionDC->getAsDecl())) {
auto actorIsolation = getActorIsolation(funcDecl);
switch (actorIsolation.getKind()) {
case ActorIsolation::Unspecified:
case ActorIsolation::Nonisolated:
case ActorIsolation::NonisolatedUnsafe:
break;
case ActorIsolation::Erased:
llvm_unreachable("method cannot have erased isolation");
case ActorIsolation::ActorInstance: {
// Only produce an executor for actor-isolated functions that are async
// or are local functions. The former require a hop, while the latter
// are prone to dynamic data races in code that does not enforce Sendable
// completely.
if (F.isAsync() ||
(wantDataRaceChecks && funcDecl->isLocalCapture())) {
auto loweredCaptures = SGM.Types.getLoweredLocalCaptures(SILDeclRef(funcDecl));
if (auto isolatedParam = loweredCaptures.getIsolatedParamCapture()) {
setExpectedExecutorForLocalVar(*this, isolatedParam);
} else {
setExpectedExecutorForParameterIsolation(*this, actorIsolation);
}
}
break;
}
case ActorIsolation::CallerIsolationInheriting:
assert(F.isAsync());
setExpectedExecutorForParameterIsolation(*this, actorIsolation);
break;
case ActorIsolation::GlobalActor:
if (F.isAsync() || wantDataRaceChecks) {
setExpectedExecutorForGlobalActor(*this, actorIsolation.getGlobalActor());
}
break;
}
} else if (auto *closureExpr = dyn_cast<AbstractClosureExpr>(FunctionDC)) {
bool wantExecutor = F.isAsync() || wantDataRaceChecks;
auto actorIsolation = closureExpr->getActorIsolation();
switch (actorIsolation.getKind()) {
case ActorIsolation::Unspecified:
case ActorIsolation::Nonisolated:
case ActorIsolation::CallerIsolationInheriting:
case ActorIsolation::NonisolatedUnsafe:
break;
case ActorIsolation::Erased:
llvm_unreachable("closure cannot have erased isolation");
case ActorIsolation::ActorInstance: {
if (wantExecutor) {
setExpectedExecutorForLocalVar(*this, actorIsolation.getActorInstance());
}
break;
}
case ActorIsolation::GlobalActor:
if (wantExecutor) {
setExpectedExecutorForGlobalActor(*this, actorIsolation.getGlobalActor());
break;
}
}
}
// In async functions, the generic executor is our expected executor
// if we don't have any sort of isolation.
if (!ExpectedExecutor.isValid()) {
if (F.isAsync() && !unsafelyInheritsExecutor()) {
setExpectedExecutorForGeneric(*this);
} else {
ExpectedExecutor.setUnnecessary();
}
}
assert(ExpectedExecutor.isValid());
// Jump to the expected executor.
if (ExpectedExecutor.isNecessary()) {
auto executor = ExpectedExecutor.getEager(); // never lazy
if (F.isAsync()) {
// For an async function, hop to the executor.
B.createHopToExecutor(
RegularLocation::getDebugOnlyLocation(F.getLocation(), getModule()),
executor,
/*mandatory*/ false);
} else {
// For a synchronous function, check that we're on the same executor.
// Note: if we "know" that the code is completely Sendable-safe, this
// is unnecessary. The type checker will need to make this determination.
emitPreconditionCheckExpectedExecutor(
RegularLocation::getAutoGeneratedLocation(F.getLocation()),
executor);
}
}
}
void SILGenFunction::emitConstructorExpectedExecutorProlog() {
auto ctor = cast<ConstructorDecl>(F.getDeclRef().getDecl());
// In async actor initializers that are isolated to self, we need
// to emit the ExpectedExecutor reference lazily.
if (ctor->hasAsync()) {
auto isolation = getActorIsolation(ctor);
auto selfDecl = ctor->getImplicitSelfDecl();
if (isolation.getKind() == ActorIsolation::ActorInstance &&
isolation.getActorInstance() == selfDecl) {
assert(isCtorWithHopsInjectedByDefiniteInit());
ExpectedExecutor.setLazy();
auto loc = SILLocation(selfDecl);
loc.markAsPrologue();
loc = loc.asAutoGenerated();
auto initialExecutor = emitGenericExecutor(loc);
B.createHopToExecutor(loc, initialExecutor, /*mandatory*/ false);
return;
}
}
// Otherwise, emit the normal expected executor prolog.
emitExpectedExecutorProlog();
}
void SILGenFunction::emitPrologGlobalActorHop(SILLocation loc,
Type globalActor) {
auto executor = emitLoadGlobalActorExecutor(globalActor);
ExpectedExecutor.set(executor);
B.createHopToExecutor(RegularLocation::getDebugOnlyLocation(loc, getModule()),
executor, /*mandatory*/ false);
}
SILValue SILGenFunction::emitMainExecutor(SILLocation loc) {
auto &ctx = getASTContext();
auto builtinName = ctx.getIdentifier(
getBuiltinName(BuiltinValueKind::BuildMainActorExecutorRef));
auto resultType = SILType::getPrimitiveObjectType(ctx.TheExecutorType);
return B.createBuiltin(loc, builtinName, resultType, {}, {});
}
SILValue SILGenFunction::emitGenericExecutor(SILLocation loc) {
// The generic executor is encoded as the nil value of
// std::optional<Builtin.SerialExecutor>.
auto ty = SILType::getOptionalType(
SILType::getPrimitiveObjectType(
getASTContext().TheExecutorType));
return B.createOptionalNone(loc, ty);
}
ManagedValue SILGenFunction::emitNonIsolatedIsolation(SILLocation loc) {
return B.createManagedOptionalNone(loc,
SILType::getOpaqueIsolationType(getASTContext()));
}
SILValue SILGenFunction::emitLoadGlobalActorExecutor(Type globalActor) {
auto loc = RegularLocation::getAutoGeneratedLocation(F.getLocation());
auto actorAndFormalType =
emitLoadOfGlobalActorShared(loc, globalActor->getCanonicalType());
return emitLoadActorExecutor(loc, actorAndFormalType.first);
}
std::pair<ManagedValue, CanType>
SILGenFunction::emitLoadOfGlobalActorShared(SILLocation loc, CanType actorType) {
NominalTypeDecl *nominal = actorType->getNominalOrBoundGenericNominal();
VarDecl *sharedInstanceDecl = nominal->getGlobalActorInstance();
assert(sharedInstanceDecl && "no shared actor field in global actor");
SubstitutionMap subs =
actorType->getContextSubstitutionMap();
Type instanceType =
actorType->getTypeOfMember(sharedInstanceDecl);
auto metaRepr =
nominal->isResilient(SGM.SwiftModule, F.getResilienceExpansion())
? MetatypeRepresentation::Thick
: MetatypeRepresentation::Thin;
CanType actorMetaType = CanMetatypeType::get(actorType, metaRepr);
ManagedValue actorMetaTypeValue =
ManagedValue::forObjectRValueWithoutOwnership(B.createMetatype(
loc, SILType::getPrimitiveObjectType(actorMetaType)));
RValue actorInstanceRV = emitRValueForStorageLoad(loc, actorMetaTypeValue,
actorMetaType, /*isSuper*/ false, sharedInstanceDecl, PreparedArguments(),
subs, AccessSemantics::Ordinary, instanceType, SGFContext());
ManagedValue actorInstance = std::move(actorInstanceRV).getScalarValue();
return {actorInstance, instanceType->getCanonicalType()};
}
ManagedValue
SILGenFunction::emitGlobalActorIsolation(SILLocation loc,
CanType globalActorType) {
// Load the .shared property. Note that this isn't necessarily a value
// of the global actor type.
auto actorAndFormalType = emitLoadOfGlobalActorShared(loc, globalActorType);
// Since it's just a normal actor instance, we can use the normal path.
return emitActorInstanceIsolation(loc, actorAndFormalType.first,
actorAndFormalType.second);
}
static ProtocolConformanceRef
getActorConformance(SILGenFunction &SGF, CanType actorType) {
auto &ctx = SGF.getASTContext();
auto proto = ctx.getProtocol(KnownProtocolKind::Actor);
return lookupConformance(actorType, proto);
}
static ProtocolConformanceRef
getDistributedActorConformance(SILGenFunction &SGF, CanType actorType) {
auto &ctx = SGF.getASTContext();
auto proto = ctx.getProtocol(KnownProtocolKind::DistributedActor);
return lookupConformance(actorType, proto);
}
/// Given a value of some non-optional distributed actor type, convert it
/// to the non-optional `any Actor` type.
static ManagedValue
emitDistributedActorIsolation(SILGenFunction &SGF, SILLocation loc,
ManagedValue actor, CanType actorType) {
// First, open the actor type if it's an existential type.
if (actorType->isExistentialType()) {
CanType openedType = OpenedArchetypeType::getAny(actorType)
->getCanonicalType();
SILType loweredOpenedType = SGF.getLoweredType(openedType);
actor = SGF.emitOpenExistential(loc, actor, loweredOpenedType,
AccessKind::Read);
actorType = openedType;
}
// Build <T: DistributedActor> and its substitutions for actorType.
// Doing this manually is ill-advised in general, but this is such a
// simple case that it's okay.
auto distributedActorConf = getDistributedActorConformance(SGF, actorType);
auto sig = distributedActorConf.getRequirement()->getGenericSignature();
auto distributedActorSubs = SubstitutionMap::get(sig, {actorType},
{distributedActorConf});
// Use that to build the magical conformance to Actor for the distributed
// actor type.
return SGF.emitDistributedActorAsAnyActor(loc, distributedActorSubs, actor);
}
/// Given a value of some non-optional actor type, convert it to
/// non-optional `any Actor` type.
static ManagedValue
emitNonOptionalActorInstanceIsolation(SILGenFunction &SGF, SILLocation loc,
ManagedValue actor, CanType actorType,
SILType anyActorTy) {
// If we have an `any Actor` already, we're done.
if (actor.getType() == anyActorTy)
return actor;
CanType anyActorType = anyActorTy.getASTType();
// If the actor is a distributed actor, (1) it had better be local
// and (2) we need to use the special conformance.
if (actorType->isDistributedActor()) {
return emitDistributedActorIsolation(SGF, loc, actor, actorType);
}
return SGF.emitTransformExistential(loc, actor, actorType, anyActorType);
}
ManagedValue
SILGenFunction::emitActorInstanceIsolation(SILLocation loc, ManagedValue actor,
CanType actorType) {
// $Optional<any Actor>
auto optionalAnyActorTy = SILType::getOpaqueIsolationType(getASTContext());
// Optional<any Actor> as a formal type (it's invariant to lowering)
auto optionalAnyActorType = optionalAnyActorTy.getASTType();
// If we started with an Optional<any Actor>, we're done.
if (actorType == optionalAnyActorType) {
return actor;
}
// Otherwise, if we have an optional value, we need to transform the payload.
auto actorObjectType = actorType.getOptionalObjectType();
if (actorObjectType) {
return emitOptionalToOptional(loc, actor, optionalAnyActorTy,
[&](SILGenFunction &SGF, SILLocation loc, ManagedValue actorObject,
SILType anyActorTy, SGFContext C) {
return emitNonOptionalActorInstanceIsolation(*this, loc, actorObject,
actorObjectType, anyActorTy);
});
}
// Otherwise, transform the non-optional value we have, then inject that
// into Optional.
SILType anyActorTy = optionalAnyActorTy.getOptionalObjectType();
ManagedValue anyActor =
emitNonOptionalActorInstanceIsolation(*this, loc, actor, actorType,
anyActorTy);
// Inject into `Optional`.
auto result = B.createOptionalSome(loc, anyActor);
return result;
}
SILValue SILGenFunction::emitLoadActorExecutor(SILLocation loc,
ManagedValue actor) {
// FIXME: Checking for whether we're in a formal evaluation scope
// like this doesn't seem like a good pattern.
SILValue actorV;
if (isInFormalEvaluationScope())
actorV = actor.formalAccessBorrow(*this, loc).getValue();
else
actorV = actor.borrow(*this, loc).getValue();
// For now, we just want to emit a hop_to_executor directly to the
// actor; LowerHopToActor will add the emission logic necessary later.
return actorV;
}
/// If we are in an actor initializer that is isolated to self, the
/// current isolation is flow-sensitive: it will be nil before self is
/// initialized, and afterwards it will be the value of self.
/// Call a builtin that the definite initialization pass will rewrite.
ManagedValue
SILGenFunction::emitFlowSensitiveSelfIsolation(SILLocation loc,
ActorIsolation isolation) {
auto isolatedVar = isolation.getActorInstance();
#ifndef NDEBUG
{
auto ctor = cast<ConstructorDecl>(F.getDeclRef().getDecl());
assert(isolatedVar == ctor->getImplicitSelfDecl());
}
#endif
CanType actorType = isolatedVar->getTypeInContext()->getCanonicalType();
assert(actorType->isAnyActorType());
ASTContext &ctx = getASTContext();
Identifier builtinName;
ProtocolConformanceRef conformance;
if (isolation.isDistributedActor()) {
// Create a reference to the asLocalActor getter. We don't call this
// immediately, but we need to make sure it's available later when the
// mandatory passes clean this up.
auto asLocalActorDecl = getDistributedActorAsLocalActorComputedProperty(
F.getDeclContext()->getParentModule());
auto asLocalActorGetter = asLocalActorDecl->getAccessor(AccessorKind::Get);
SILDeclRef asLocalActorRef = SILDeclRef(
asLocalActorGetter, SILDeclRef::Kind::Func);
(void) emitGlobalFunctionRef(loc, asLocalActorRef);
builtinName = ctx.getIdentifier(
getBuiltinName(BuiltinValueKind::FlowSensitiveDistributedSelfIsolation));
conformance = getDistributedActorConformance(*this, actorType);
} else {
builtinName = ctx.getIdentifier(
getBuiltinName(BuiltinValueKind::FlowSensitiveSelfIsolation));
conformance = getActorConformance(*this, actorType);
}
SGM.useConformance(conformance);
SubstitutionMap subs = SubstitutionMap::getProtocolSubstitutions(
conformance.getRequirement(), actorType, conformance);
auto origActor =
maybeEmitValueOfLocalVarDecl(isolatedVar, AccessKind::Read).getValue();
SILType resultTy = SILType::getOpaqueIsolationType(ctx);
auto call = B.createBuiltin(loc, builtinName, resultTy, subs, origActor);
return ManagedValue::forForwardedRValue(*this, call);
}
SILValue SILGenFunction::emitLoadErasedExecutor(SILLocation loc,
ManagedValue fn) {
// As with emitLoadActorExecutor, we just emit the actor reference
// for now and let LowerHopToActor deal with the executor projection.
return emitLoadErasedIsolation(loc, fn).getUnmanagedValue();
}
ManagedValue
SILGenFunction::emitLoadErasedIsolation(SILLocation loc,
ManagedValue fn) {
fn = fn.borrow(*this, loc);
// This expects a borrowed function and returns a borrowed (any Actor)?.
auto actor = B.createFunctionExtractIsolation(loc, fn.getValue());
return ManagedValue::forBorrowedObjectRValue(actor);
}
ManagedValue
SILGenFunction::emitFunctionTypeIsolation(SILLocation loc,
FunctionTypeIsolation isolation,
ManagedValue fn) {
switch (isolation.getKind()) {
// Parameter-isolated functions don't have a specific actor they're isolated
// to; they're essentially polymorphic over isolation.
case FunctionTypeIsolation::Kind::Parameter:
llvm_unreachable("cannot load isolation from parameter-isoaltion function "
"reference");
// Emit nonisolated by simply emitting Optional.none in the result type.
case FunctionTypeIsolation::Kind::NonIsolated:
return emitNonIsolatedIsolation(loc);
// Emit global actor isolation by loading .shared from the global actor,
// erasing it into `any Actor`, and injecting that into Optional.
case FunctionTypeIsolation::Kind::GlobalActor:
return emitGlobalActorIsolation(loc,
isolation.getGlobalActorType()->getCanonicalType());
// Emit @isolated(any) isolation by loading the actor reference from the
// function.
case FunctionTypeIsolation::Kind::Erased: {
Scope scope(*this, CleanupLocation(loc));
auto value = emitLoadErasedIsolation(loc, fn).copy(*this, loc);
return scope.popPreservingValue(value);
}
}
llvm_unreachable("bad kind");
}
static ActorIsolation getClosureIsolationInfo(SILDeclRef constant) {
if (auto closure = constant.getAbstractClosureExpr()) {
return closure->getActorIsolation();
}
auto func = constant.getAbstractFunctionDecl();
assert(func && "unexpected closure constant");
return getActorIsolation(func);
}
static ManagedValue emitLoadOfCaptureIsolation(SILGenFunction &SGF,
SILLocation loc,
VarDecl *isolatedCapture,
SILDeclRef constant,
ArrayRef<ManagedValue> captureArgs) {
auto &TC = SGF.SGM.Types;
auto captureInfo = TC.getLoweredLocalCaptures(constant);
auto isolatedVarType = isolatedCapture->getTypeInContext()->getCanonicalType();
// Capture arguments are 1-1 with the lowered capture info.
auto captures = captureInfo.getCaptures();
for (auto i : indices(captures)) {
const auto &capture = captures[i];
if (capture.isDynamicSelfMetadata()) continue;
auto capturedVar = capture.getDecl();
if (capturedVar != isolatedCapture) continue;
// Captured actor references should always be captured as constants.
assert(TC.getDeclCaptureKind(capture,
TC.getCaptureTypeExpansionContext(constant))
== CaptureKind::Constant);
auto value = captureArgs[i].copy(SGF, loc);
return SGF.emitActorInstanceIsolation(loc, value, isolatedVarType);
}
// The capture not being a lowered capture can happen in global code.
auto value = SGF.emitRValueForDecl(loc, isolatedCapture, isolatedVarType,
AccessSemantics::Ordinary)
.getAsSingleValue(SGF, loc);
return SGF.emitActorInstanceIsolation(loc, value, isolatedVarType);
}
ManagedValue
SILGenFunction::emitClosureIsolation(SILLocation loc, SILDeclRef constant,
ArrayRef<ManagedValue> captures) {
auto isolation = getClosureIsolationInfo(constant);
switch (isolation) {
case ActorIsolation::Unspecified:
case ActorIsolation::Nonisolated:
case ActorIsolation::CallerIsolationInheriting:
case ActorIsolation::NonisolatedUnsafe:
return emitNonIsolatedIsolation(loc);
case ActorIsolation::Erased:
llvm_unreachable("closures cannot directly have erased isolation");
case ActorIsolation::GlobalActor:
return emitGlobalActorIsolation(loc,
isolation.getGlobalActor()->getCanonicalType());
case ActorIsolation::ActorInstance: {
// This should always be a capture. That's not expressed super-cleanly
// in ActorIsolation, unfortunately.
assert(isolation.getActorInstanceParameter() == 0);
auto capture = isolation.getActorInstance();
assert(capture);
return emitLoadOfCaptureIsolation(*this, loc, capture, constant, captures);
}
}
llvm_unreachable("bad kind");
}
ExecutorBreadcrumb
SILGenFunction::emitHopToTargetActor(SILLocation loc,
std::optional<ActorIsolation> maybeIso,
std::optional<ManagedValue> maybeSelf) {
if (!maybeIso)
return ExecutorBreadcrumb();
if (auto executor = emitExecutor(loc, *maybeIso, maybeSelf)) {
return emitHopToTargetExecutor(loc, *executor);
} else {
return ExecutorBreadcrumb();
}
}
ExecutorBreadcrumb SILGenFunction::emitHopToTargetExecutor(
SILLocation loc, SILValue executor) {
// Record that we need to hop back to the current executor.
auto breadcrumb = ExecutorBreadcrumb(true);
B.createHopToExecutor(RegularLocation::getDebugOnlyLocation(loc, getModule()),
executor, /*mandatory*/ false);
return breadcrumb;
}
std::optional<SILValue>
SILGenFunction::emitExecutor(SILLocation loc, ActorIsolation isolation,
std::optional<ManagedValue> maybeSelf) {
switch (isolation.getKind()) {
case ActorIsolation::Unspecified:
case ActorIsolation::Nonisolated:
case ActorIsolation::CallerIsolationInheriting:
case ActorIsolation::NonisolatedUnsafe:
return std::nullopt;
case ActorIsolation::Erased:
llvm_unreachable("executor emission for erased isolation is unimplemented");
case ActorIsolation::ActorInstance: {
// "self" here means the actor instance's "self" value.
assert(maybeSelf.has_value() && "actor-instance but no self provided?");
auto self = maybeSelf.value();
return emitLoadActorExecutor(loc, self);
}
case ActorIsolation::GlobalActor:
return emitLoadGlobalActorExecutor(isolation.getGlobalActor());
}
llvm_unreachable("covered switch");
}
void SILGenFunction::emitHopToActorValue(SILLocation loc, ManagedValue actor) {
// TODO: can the type system enforce this async requirement?
if (!F.isAsync()) {
llvm::report_fatal_error("Builtin.hopToActor must be in an async function");
}
auto isolation =
getActorIsolationOfContext(FunctionDC, [](AbstractClosureExpr *CE) {
return CE->getActorIsolation();
});
if (isolation != ActorIsolation::Nonisolated &&
isolation != ActorIsolation::NonisolatedUnsafe &&
isolation != ActorIsolation::Unspecified) {
// TODO: Explicit hop with no hop-back should only be allowed in nonisolated
// async functions. But it needs work for any closure passed to
// Task.detached, which currently has unspecified isolation.
llvm::report_fatal_error(
"Builtin.hopToActor must be in an actor-independent function");
}
SILValue executor = emitLoadActorExecutor(loc, actor);
B.createHopToExecutor(RegularLocation::getDebugOnlyLocation(loc, getModule()),
executor, /*mandatory*/ true);
}
static bool isCheckExpectedExecutorIntrinsicAvailable(SILGenModule &SGM) {
auto checkExecutor = SGM.getCheckExpectedExecutor();
if (!checkExecutor)
return false;
// Forego a check if instrinsic is unavailable, this could happen
// in main-actor context.
auto &C = checkExecutor->getASTContext();
if (!C.LangOpts.DisableAvailabilityChecking) {
auto deploymentAvailability = AvailabilityRange::forDeploymentTarget(C);
auto declAvailability =
AvailabilityInference::availableRange(checkExecutor);
return deploymentAvailability.isContainedIn(declAvailability);
}
return true;
}
void SILGenFunction::emitPreconditionCheckExpectedExecutor(
SILLocation loc, ActorIsolation isolation,
std::optional<ManagedValue> actorSelf) {
if (!isCheckExpectedExecutorIntrinsicAvailable(SGM))
return;
auto executor = emitExecutor(loc, isolation, actorSelf);
assert(executor);
emitPreconditionCheckExpectedExecutor(loc, *executor);
}
void SILGenFunction::emitPreconditionCheckExpectedExecutor(
SILLocation loc, SILValue executorOrActor) {
if (!isCheckExpectedExecutorIntrinsicAvailable(SGM))
return;
// We don't want the debugger to step into these.
loc.markAutoGenerated();
// If the function is isolated to an optional actor reference,
// check dynamically whether it's non-null. We don't need to
// do an assertion if the expected expected is nil.
SILBasicBlock *noneBB = nullptr;
bool isOptional = (bool) executorOrActor->getType().getOptionalObjectType();
if (isOptional) {
// Start by emiting the .some path.
noneBB = createBasicBlock();
auto someBB = createBasicBlockBefore(noneBB);
executorOrActor =
B.createSwitchOptional(loc, executorOrActor, someBB, noneBB,
executorOrActor->getOwnershipKind());
B.emitBlock(someBB);
}
// Get the executor.
SILValue executor = B.createExtractExecutor(loc, executorOrActor);
// Call the library function that performs the checking.
auto args = emitSourceLocationArgs(loc.getSourceLoc(), loc);
emitApplyOfLibraryIntrinsic(
loc, SGM.getCheckExpectedExecutor(), SubstitutionMap(),
{args.filenameStartPointer, args.filenameLength, args.filenameIsAscii,
args.line, ManagedValue::forObjectRValueWithoutOwnership(executor)},
SGFContext());
// Complete the optional control flow if we had an optional value.
if (isOptional) {
assert(noneBB);
// Finish the .some path by branching to the continuation block.
auto contBB = createBasicBlockAfter(noneBB);
B.createBranch(loc, contBB);
// The .none path is trivial.
B.emitBlock(noneBB);
B.createBranch(loc, contBB);
B.emitBlock(contBB);
}
}
bool SILGenFunction::unsafelyInheritsExecutor() {
if (auto fn = dyn_cast<AbstractFunctionDecl>(FunctionDC))
return fn->getAttrs().hasAttribute<UnsafeInheritExecutorAttr>();
return false;
}
void ExecutorBreadcrumb::emit(SILGenFunction &SGF, SILLocation loc) {
if (mustReturnToExecutor) {
assert(SGF.ExpectedExecutor.isValid());
if (SGF.ExpectedExecutor.isNecessary()) {
FullExpr scope(SGF.Cleanups, CleanupLocation(loc));
auto executor = SGF.emitExpectedExecutor(loc);
SGF.B.createHopToExecutor(
RegularLocation::getDebugOnlyLocation(loc, SGF.getModule()),
executor.getValue(), /*mandatory*/ false);
}
}
}
ManagedValue SILGenFunction::emitExpectedExecutor(SILLocation loc) {
assert(ExpectedExecutor.isNecessary() &&
"prolog failed to set up expected executor?");
// Fast (common) path: we have an eagerly-set expected executor.
if (ExpectedExecutor.isEager()) {
return ManagedValue::forBorrowedObjectRValue(ExpectedExecutor.getEager());
}
// Otherwise, the current function must have lazy, flow-sensitive isolation.
auto ctor = cast<ConstructorDecl>(F.getDeclRef().getDecl());
auto isolation = getActorIsolation(ctor);
return emitFlowSensitiveSelfIsolation(loc, isolation);
}
ManagedValue
SILGenFunction::emitDistributedActorAsAnyActor(SILLocation loc,
SubstitutionMap distributedActorSubs,
ManagedValue actorValue) {
auto &ctx = SGM.getASTContext();
auto distributedActorAsActorConformance =
getDistributedActorAsActorConformance(ctx);
auto actorProto = ctx.getProtocol(KnownProtocolKind::Actor);
auto distributedActorType = distributedActorSubs.getReplacementTypes()[0];
auto ref = ProtocolConformanceRef(ctx.getSpecializedConformance(
distributedActorType, distributedActorAsActorConformance,
distributedActorSubs));
ProtocolConformanceRef conformances[1] = {ref};
// Erase the distributed actor instance into an `any Actor` existential with
// the special conformance.
CanType distributedActorCanType = distributedActorType->getCanonicalType();
auto &distributedActorTL = getTypeLowering(distributedActorCanType);
auto &anyActorTL = getTypeLowering(actorProto->getDeclaredExistentialType());
return emitExistentialErasure(
loc, distributedActorCanType, distributedActorTL, anyActorTL,
ctx.AllocateCopy(conformances), SGFContext(),
[actorValue](SGFContext) { return actorValue; });
}