Files
swift-mirror/lib/AST/AvailabilityConstraint.cpp
Allan Shortlidge 707c4aa52c AST: Factor out a utility for computing runtime unavailability.
In anticipation of needing to compute runtime unavailability to determine
whether declarations should be printed in swiftinterfaces, factor out the code
that computes runtime unavailability into a shared utility based on
`DeclAvailabilityConstraints`.

NFC.
2025-09-02 23:18:05 -07:00

355 lines
13 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/Decl.h"
using namespace swift;
AvailabilityDomainAndRange
AvailabilityConstraint::getDomainAndRange(const ASTContext &ctx) const {
switch (getReason()) {
case Reason::UnavailableUnconditionally:
case Reason::UnavailableObsolete:
return getAttr().getObsoletedDomainAndRange(ctx).value();
case Reason::UnavailableUnintroduced:
case Reason::Unintroduced:
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);
}
void AvailabilityConstraint::print(llvm::raw_ostream &os) const {
os << "AvailabilityConstraint(";
getAttr().getDomain().print(os);
os << ", ";
std::optional<llvm::VersionTuple> version;
switch (getReason()) {
case Reason::UnavailableUnconditionally:
os << "unavailable";
break;
case Reason::UnavailableObsolete:
os << "obsoleted";
version = getAttr().getObsoleted();
break;
case Reason::UnavailableUnintroduced:
case Reason::Unintroduced:
os << "introduced";
version = getAttr().getIntroduced();
break;
}
if (version)
os << ": " << *version;
os << ")";
}
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::UnavailableUnconditionally:
// Just keep the first.
return false;
case AvailabilityConstraint::Reason::UnavailableObsolete:
// Pick the larger obsoleted range.
return lhs.getAttr().getObsoleted().value() <
rhs.getAttr().getObsoleted().value();
case AvailabilityConstraint::Reason::UnavailableUnintroduced:
case AvailabilityConstraint::Reason::Unintroduced:
// Pick the smaller introduced range.
return lhs.getAttr().getIntroduced().value_or(llvm::VersionTuple()) >
rhs.getAttr().getIntroduced().value_or(llvm::VersionTuple());
}
}
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;
}
void DeclAvailabilityConstraints::print(llvm::raw_ostream &os) const {
os << "{\n";
llvm::interleave(
constraints,
[&os](const AvailabilityConstraint &constraint) {
os << " " << constraint;
},
[&os] { os << ",\n"; });
os << "\n}";
}
static bool canIgnoreConstraintInUnavailableContexts(
const Decl *decl, const AvailabilityConstraint &constraint,
const AvailabilityConstraintFlags flags) {
auto domain = constraint.getDomain();
// 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 (!flags.contains(AvailabilityConstraintFlag::
AllowUniversallyUnavailableInCompatibleContexts)) {
if (!isa<TypeDecl>(decl) && !isa<ExtensionDecl>(decl)) {
if (domain.isUniversal() || domain.isSwiftLanguage())
return false;
}
}
switch (constraint.getReason()) {
case AvailabilityConstraint::Reason::UnavailableUnconditionally:
return true;
case AvailabilityConstraint::Reason::Unintroduced:
case AvailabilityConstraint::Reason::UnavailableObsolete:
case AvailabilityConstraint::Reason::UnavailableUnintroduced:
return domain.isVersioned();
}
}
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::unavailableUnconditionally(attr);
auto &ctx = decl->getASTContext();
auto domain = attr.getDomain();
auto deploymentRange = domain.getDeploymentRange(ctx);
bool domainSupportsRefinement = domain.supportsContextRefinement();
std::optional<AvailabilityRange> availableRange =
domainSupportsRefinement ? context.getAvailabilityRange(domain, ctx)
: deploymentRange;
// Is the decl obsoleted in this context?
if (auto obsoletedRange = attr.getObsoletedRange(ctx)) {
if (availableRange && availableRange->isContainedIn(*obsoletedRange))
return AvailabilityConstraint::unavailableObsolete(attr);
}
// Is the decl not yet introduced in this context?
if (auto introducedRange = attr.getIntroducedRange(ctx)) {
if (!availableRange || !availableRange->isContainedIn(*introducedRange))
return domainSupportsRefinement
? AvailabilityConstraint::unintroduced(attr)
: AvailabilityConstraint::unavailableUnintroduced(attr);
}
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 = decl->parentDeclForAvailability();
if (auto extension = dyn_cast_or_null<ExtensionDecl>(parent))
getAvailabilityConstraintsForDecl(constraints, extension, context, flags);
return constraints;
}
std::optional<AvailabilityConstraint>
swift::getAvailabilityConstraintForDeclInDomain(
const Decl *decl, const AvailabilityContext &context,
AvailabilityDomain domain, AvailabilityConstraintFlags flags) {
auto constraints = getAvailabilityConstraintsForDecl(decl, context, flags);
for (auto const &constraint : constraints) {
if (constraint.getDomain().isRelated(domain))
return constraint;
}
return std::nullopt;
}
static bool constraintIndicatesRuntimeUnavailability(
const AvailabilityConstraint &constraint, const ASTContext &ctx) {
std::optional<CustomAvailabilityDomain::Kind> customDomainKind;
if (auto customDomain = constraint.getDomain().getCustomDomain())
customDomainKind = customDomain->getKind();
switch (constraint.getReason()) {
case AvailabilityConstraint::Reason::UnavailableUnconditionally:
if (customDomainKind)
return customDomainKind == CustomAvailabilityDomain::Kind::Enabled;
return true;
case AvailabilityConstraint::Reason::UnavailableObsolete:
case AvailabilityConstraint::Reason::UnavailableUnintroduced:
return false;
case AvailabilityConstraint::Reason::Unintroduced:
if (customDomainKind)
return customDomainKind == CustomAvailabilityDomain::Kind::Disabled;
return false;
}
}
void swift::getRuntimeUnavailableDomains(
const DeclAvailabilityConstraints &constraints,
llvm::SmallVectorImpl<AvailabilityDomain> &domains, const ASTContext &ctx) {
for (auto constraint : constraints) {
if (constraintIndicatesRuntimeUnavailability(constraint, ctx))
domains.push_back(constraint.getDomain());
}
}