Files
swift-mirror/lib/AST/AvailabilityConstraint.cpp
Allan Shortlidge 99380bf00f Sema: Sometimes allow universally unavailable declarations to be referenced.
In implicit contexts that are universally unavailable, allow writable key paths
to be formed to properties with setters that are also marked as universally
unavailable. This fixes a regression from the previous commit where the code
synthesized for `@Observable` properties in universally unavailable classes was
rejected by the availability checker.
2025-07-15 14:08:57 -07:00

302 lines
12 KiB
C++

//===--- AvailabilityConstraint.cpp - Swift Availability Constraints ------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "swift/AST/AvailabilityConstraint.h"
#include "swift/AST/ASTContext.h"
#include "swift/AST/AvailabilityContext.h"
#include "swift/AST/AvailabilityInference.h"
#include "swift/AST/Decl.h"
using namespace swift;
AvailabilityDomainAndRange
AvailabilityConstraint::getDomainAndRange(const ASTContext &ctx) const {
switch (getReason()) {
case Reason::UnconditionallyUnavailable:
// Technically, unconditional unavailability doesn't have an associated
// range. However, if you view it as a special case of obsoletion, then an
// unconditionally unavailable declaration is "always obsoleted."
return AvailabilityDomainAndRange(getDomain().getRemappedDomain(ctx),
AvailabilityRange::alwaysAvailable());
case Reason::Obsoleted:
return getAttr().getObsoletedDomainAndRange(ctx).value();
case Reason::UnavailableForDeployment:
case Reason::PotentiallyUnavailable:
return getAttr().getIntroducedDomainAndRange(ctx).value();
}
}
bool AvailabilityConstraint::isActiveForRuntimeQueries(
const ASTContext &ctx) const {
if (getAttr().getPlatform() == PlatformKind::none)
return true;
return swift::isPlatformActive(getAttr().getPlatform(), ctx.LangOpts,
/*forTargetVariant=*/false,
/*forRuntimeQuery=*/true);
}
static bool constraintIsStronger(const AvailabilityConstraint &lhs,
const AvailabilityConstraint &rhs) {
DEBUG_ASSERT(lhs.getDomain() == rhs.getDomain());
// If the constraints have matching domains but different reasons, the
// constraint with the lowest reason is "strongest".
if (lhs.getReason() != rhs.getReason())
return lhs.getReason() < rhs.getReason();
switch (lhs.getReason()) {
case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
// Just keep the first.
return false;
case AvailabilityConstraint::Reason::Obsoleted:
// Pick the larger obsoleted range.
return *lhs.getAttr().getObsoleted() < *rhs.getAttr().getObsoleted();
case AvailabilityConstraint::Reason::UnavailableForDeployment:
case AvailabilityConstraint::Reason::PotentiallyUnavailable:
// Pick the smaller introduced range.
return *lhs.getAttr().getIntroduced() > *rhs.getAttr().getIntroduced();
}
}
void addConstraint(llvm::SmallVector<AvailabilityConstraint, 4> &constraints,
const AvailabilityConstraint &constraint,
const ASTContext &ctx) {
auto iter = llvm::find_if(
constraints, [&constraint](AvailabilityConstraint &existing) {
return constraint.getDomain() == existing.getDomain();
});
// There's no existing constraint for the same domain so just add it.
if (iter == constraints.end()) {
constraints.emplace_back(constraint);
return;
}
if (constraintIsStronger(constraint, *iter)) {
constraints.erase(iter);
constraints.emplace_back(constraint);
}
}
std::optional<AvailabilityConstraint>
DeclAvailabilityConstraints::getPrimaryConstraint() const {
std::optional<AvailabilityConstraint> result;
auto isStrongerConstraint = [](const AvailabilityConstraint &lhs,
const AvailabilityConstraint &rhs) {
// Constraint reasons are defined in descending order of strength.
if (lhs.getReason() != rhs.getReason())
return lhs.getReason() < rhs.getReason();
// Pick the constraint from the broader domain.
if (lhs.getDomain() != rhs.getDomain())
return rhs.getDomain().contains(lhs.getDomain());
return false;
};
// Pick the strongest constraint.
for (auto const &constraint : constraints) {
if (!result || isStrongerConstraint(constraint, *result))
result.emplace(constraint);
}
return result;
}
static bool canIgnoreConstraintInUnavailableContexts(
const Decl *decl, const AvailabilityConstraint &constraint,
const AvailabilityConstraintFlags flags) {
auto domain = constraint.getDomain();
switch (constraint.getReason()) {
case AvailabilityConstraint::Reason::UnconditionallyUnavailable:
if (flags.contains(AvailabilityConstraintFlag::
AllowUniversallyUnavailableInCompatibleContexts))
return true;
// Always reject uses of universally unavailable declarations, regardless
// of context, since there are no possible compilation configurations in
// which they are available. However, make an exception for types and
// conformances, which can sometimes be awkward to avoid references to.
if (!isa<TypeDecl>(decl) && !isa<ExtensionDecl>(decl)) {
if (domain.isUniversal() || domain.isSwiftLanguage())
return false;
}
return true;
case AvailabilityConstraint::Reason::PotentiallyUnavailable:
switch (domain.getKind()) {
case AvailabilityDomain::Kind::Universal:
case AvailabilityDomain::Kind::SwiftLanguage:
case AvailabilityDomain::Kind::PackageDescription:
case AvailabilityDomain::Kind::Embedded:
case AvailabilityDomain::Kind::Custom:
return false;
case AvailabilityDomain::Kind::Platform:
// Platform availability only applies to the target triple that the
// binary is being compiled for. Since the same declaration can be
// potentially unavailable from a given context when compiling for one
// platform, but available from that context when compiling for a
// different platform, it is overly strict to enforce potential platform
// unavailability constraints in contexts that are unavailable to that
// platform.
return true;
}
return constraint.getDomain().isPlatform();
case AvailabilityConstraint::Reason::Obsoleted:
case AvailabilityConstraint::Reason::UnavailableForDeployment:
return false;
}
}
static bool
shouldIgnoreConstraintInContext(const Decl *decl,
const AvailabilityConstraint &constraint,
const AvailabilityContext &context,
const AvailabilityConstraintFlags flags) {
if (!context.isUnavailable())
return false;
if (!canIgnoreConstraintInUnavailableContexts(decl, constraint, flags))
return false;
return context.containsUnavailableDomain(constraint.getDomain());
}
/// Returns the `AvailabilityConstraint` that describes how \p attr restricts
/// use of \p decl in \p context or `std::nullopt` if there is no restriction.
static std::optional<AvailabilityConstraint>
getAvailabilityConstraintForAttr(const Decl *decl,
const SemanticAvailableAttr &attr,
const AvailabilityContext &context) {
// Is the decl unconditionally unavailable?
if (attr.isUnconditionallyUnavailable())
return AvailabilityConstraint::unconditionallyUnavailable(attr);
auto &ctx = decl->getASTContext();
auto domain = attr.getDomain();
auto deploymentRange = domain.getDeploymentRange(ctx);
// Is the decl obsoleted in the deployment context?
if (auto obsoletedRange = attr.getObsoletedRange(ctx)) {
if (deploymentRange && deploymentRange->isContainedIn(*obsoletedRange))
return AvailabilityConstraint::obsoleted(attr);
}
// Is the decl not yet introduced in the local context?
if (auto introducedRange = attr.getIntroducedRange(ctx)) {
if (domain.supportsContextRefinement()) {
auto availableRange = context.getAvailabilityRange(domain, ctx);
if (!availableRange || !availableRange->isContainedIn(*introducedRange))
return AvailabilityConstraint::potentiallyUnavailable(attr);
return std::nullopt;
}
// Is the decl not yet introduced in the deployment context?
if (deploymentRange && !deploymentRange->isContainedIn(*introducedRange))
return AvailabilityConstraint::unavailableForDeployment(attr);
}
// FIXME: [availability] Model deprecation as an availability constraint.
return std::nullopt;
}
/// Returns the most specific platform domain from the availability attributes
/// attached to \p decl or `std::nullopt` if there are none. Platform specific
/// `@available` attributes for other platforms should be ignored. For example,
/// if a declaration has attributes for both iOS and macCatalyst, only the
/// macCatalyst attributes take effect when compiling for a macCatalyst target.
static std::optional<AvailabilityDomain>
activePlatformDomainForDecl(const Decl *decl) {
std::optional<AvailabilityDomain> activeDomain;
for (auto attr :
decl->getSemanticAvailableAttrs(/*includingInactive=*/false)) {
auto domain = attr.getDomain();
if (!domain.isPlatform())
continue;
if (activeDomain && domain.contains(*activeDomain))
continue;
activeDomain.emplace(domain);
}
return activeDomain;
}
static void getAvailabilityConstraintsForDecl(
llvm::SmallVector<AvailabilityConstraint, 4> &constraints, const Decl *decl,
const AvailabilityContext &context, AvailabilityConstraintFlags flags) {
auto &ctx = decl->getASTContext();
auto activePlatformDomain = activePlatformDomainForDecl(decl);
bool includeAllDomains =
flags.contains(AvailabilityConstraintFlag::IncludeAllDomains);
for (auto attr : decl->getSemanticAvailableAttrs(includeAllDomains)) {
auto domain = attr.getDomain();
if (!includeAllDomains && domain.isPlatform() && activePlatformDomain &&
!activePlatformDomain->contains(domain))
continue;
if (auto constraint = getAvailabilityConstraintForAttr(decl, attr, context))
addConstraint(constraints, *constraint, ctx);
}
// After resolving constraints, remove any constraints that indicate the
// declaration is unconditionally unavailable in a domain for which
// the context is already unavailable.
llvm::erase_if(constraints, [&](const AvailabilityConstraint &constraint) {
return shouldIgnoreConstraintInContext(decl, constraint, context, flags);
});
}
DeclAvailabilityConstraints
swift::getAvailabilityConstraintsForDecl(const Decl *decl,
const AvailabilityContext &context,
AvailabilityConstraintFlags flags) {
llvm::SmallVector<AvailabilityConstraint, 4> constraints;
// Generic parameters are always available.
if (isa<GenericTypeParamDecl>(decl))
return DeclAvailabilityConstraints();
decl = decl->getAbstractSyntaxDeclForAttributes();
getAvailabilityConstraintsForDecl(constraints, decl, context, flags);
if (flags.contains(AvailabilityConstraintFlag::SkipEnclosingExtension))
return constraints;
// If decl is an extension member, query the attributes of the extension, too.
//
// Skip decls imported from Clang, though, as they could be associated to the
// wrong extension and inherit unavailability incorrectly. ClangImporter
// associates Objective-C protocol members to the first category where the
// protocol is directly or indirectly adopted, no matter its availability
// and the availability of other categories. rdar://problem/53956555
if (decl->getClangNode())
return constraints;
auto parent = AvailabilityInference::parentDeclForInferredAvailability(decl);
if (auto extension = dyn_cast_or_null<ExtensionDecl>(parent))
getAvailabilityConstraintsForDecl(constraints, extension, context, flags);
return constraints;
}