mirror of
https://github.com/apple/swift.git
synced 2025-12-14 20:36:38 +01:00
a250688a50
If a conformance is found in an imported module as well as the current module, and one of the two conformances is conditionally unavailable on the current deployment target, pick the one that is always available. Fixes <rdar://problem/78633800>.
1167 lines
42 KiB
C++
1167 lines
42 KiB
C++
//===--- ConformanceLookupTable - Conformance Lookup Table ----------------===//
|
|
//
|
|
// 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the ConformanceLookupTable class.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "ConformanceLookupTable.h"
|
|
#include "swift/AST/ASTContext.h"
|
|
#include "swift/AST/Decl.h"
|
|
#include "swift/AST/ExistentialLayout.h"
|
|
#include "swift/AST/GenericParamList.h"
|
|
#include "swift/AST/LazyResolver.h"
|
|
#include "swift/AST/Module.h"
|
|
#include "swift/AST/NameLookup.h"
|
|
#include "swift/AST/SourceFile.h"
|
|
#include "swift/AST/ProtocolConformance.h"
|
|
#include "swift/AST/ProtocolConformanceRef.h"
|
|
#include "llvm/Support/SaveAndRestore.h"
|
|
|
|
using namespace swift;
|
|
|
|
DeclContext *ConformanceLookupTable::ConformanceSource::getDeclContext() const {
|
|
switch (getKind()) {
|
|
case ConformanceEntryKind::Inherited:
|
|
return getInheritingClass();
|
|
|
|
case ConformanceEntryKind::Explicit:
|
|
return getExplicitDeclContext();
|
|
|
|
case ConformanceEntryKind::Implied:
|
|
return getImpliedSource()->Source.getDeclContext();
|
|
|
|
case ConformanceEntryKind::Synthesized:
|
|
return getSynthesizedDecl();
|
|
}
|
|
|
|
llvm_unreachable("Unhandled ConformanceEntryKind in switch.");
|
|
}
|
|
|
|
ProtocolDecl *ConformanceLookupTable::ConformanceEntry::getProtocol() const {
|
|
if (auto protocol = Conformance.dyn_cast<ProtocolDecl *>())
|
|
return protocol;
|
|
|
|
return Conformance.get<ProtocolConformance *>()->getProtocol();
|
|
}
|
|
|
|
void *ConformanceLookupTable::ConformanceEntry::operator new(
|
|
size_t Bytes,
|
|
ASTContext &C,
|
|
unsigned Alignment) {
|
|
return C.Allocate(Bytes, Alignment);
|
|
}
|
|
|
|
void ConformanceLookupTable::ConformanceEntry::markSupersededBy(
|
|
ConformanceLookupTable &table,
|
|
ConformanceEntry *entry,
|
|
bool diagnose) {
|
|
assert(!isSuperseded() && "Already superseded");
|
|
|
|
// Note that we've been superseded.
|
|
SupersededBy = entry;
|
|
|
|
if (diagnose) {
|
|
// Record the problem in the conformance table. We'll
|
|
// diagnose these in semantic analysis.
|
|
table.AllSupersededDiagnostics[getDeclContext()].push_back(this);
|
|
}
|
|
}
|
|
|
|
void ConformanceLookupTable::ConformanceEntry::dump() const {
|
|
dump(llvm::errs());
|
|
}
|
|
|
|
void ConformanceLookupTable::ConformanceEntry::dump(raw_ostream &os,
|
|
unsigned indent) const {
|
|
os.indent(indent) << "(conformance @" << static_cast<const void *>(this);
|
|
|
|
os << " protocol=";
|
|
getProtocol()->dumpRef(os);
|
|
|
|
if (Loc.isValid()) {
|
|
os << " loc=";
|
|
Loc.print(os, getProtocol()->getASTContext().SourceMgr);
|
|
}
|
|
|
|
switch (getKind()) {
|
|
case ConformanceEntryKind::Implied:
|
|
os << " implied_by=@"
|
|
<< static_cast<const void *>(Source.getImpliedSource());
|
|
break;
|
|
|
|
case ConformanceEntryKind::Explicit:
|
|
os << " explicit";
|
|
break;
|
|
|
|
case ConformanceEntryKind::Inherited:
|
|
os << " inherited";
|
|
break;
|
|
|
|
case ConformanceEntryKind::Synthesized:
|
|
os << " synthesized";
|
|
break;
|
|
}
|
|
|
|
if (auto conf = getConformance()) {
|
|
os << " fixed_conformance=@" << static_cast<const void *>(conf);
|
|
}
|
|
|
|
if (SupersededBy)
|
|
os << " superseded_by=@" << static_cast<const void *>(SupersededBy);
|
|
|
|
os << ")\n";
|
|
}
|
|
|
|
void *ConformanceLookupTable::operator new(size_t Bytes,
|
|
ASTContext &C,
|
|
unsigned Alignment) {
|
|
return C.Allocate(Bytes, Alignment);
|
|
}
|
|
|
|
ConformanceLookupTable::ConformanceLookupTable(ASTContext &ctx) {
|
|
// Register a cleanup with the ASTContext to call the conformance
|
|
// table destructor.
|
|
ctx.addCleanup([this]() {
|
|
this->destroy();
|
|
});
|
|
}
|
|
|
|
void ConformanceLookupTable::destroy() {
|
|
this->~ConformanceLookupTable();
|
|
}
|
|
|
|
namespace {
|
|
using ConformanceConstructionInfo = Located<ProtocolDecl *>;
|
|
}
|
|
|
|
template<typename NominalFunc, typename ExtensionFunc>
|
|
void ConformanceLookupTable::forEachInStage(ConformanceStage stage,
|
|
NominalTypeDecl *nominal,
|
|
NominalFunc nominalFunc,
|
|
ExtensionFunc extensionFunc) {
|
|
assert(static_cast<unsigned>(stage) < NumConformanceStages &&
|
|
"NumConformanceStages has not been updated");
|
|
|
|
LastProcessedEntry &lastProcessed
|
|
= LastProcessed[nominal][static_cast<unsigned>(stage)];
|
|
|
|
// Handle the nominal type.
|
|
if (!lastProcessed.getInt()) {
|
|
lastProcessed.setInt(true);
|
|
|
|
// If we have conformances we can load, do so.
|
|
// FIXME: This could be lazier.
|
|
auto loader = nominal->takeConformanceLoader();
|
|
if (loader.first) {
|
|
SmallVector<ProtocolConformance *, 2> conformances;
|
|
loader.first->loadAllConformances(nominal, loader.second, conformances);
|
|
loadAllConformances(nominal, conformances);
|
|
}
|
|
|
|
nominalFunc(nominal);
|
|
}
|
|
|
|
// Protocol extensions do not contribute protocol conformances. This
|
|
// is enforced by semantic analysis, so the early exit here is a
|
|
// performance optimization and also prevents us from erroneously
|
|
// including those protocols before they get diagnosed.
|
|
if (isa<ProtocolDecl>(nominal))
|
|
return;
|
|
|
|
// Handle the extensions that we have not yet visited.
|
|
nominal->prepareExtensions();
|
|
while (auto next = lastProcessed.getPointer()
|
|
? lastProcessed.getPointer()->NextExtension.getPointer()
|
|
: nominal->FirstExtension) {
|
|
lastProcessed.setPointer(next);
|
|
|
|
SmallVector<ConformanceConstructionInfo, 2> protocols;
|
|
|
|
// If we have conformances we can load, do so.
|
|
// FIXME: This could be lazier.
|
|
auto loader = next->takeConformanceLoader();
|
|
if (loader.first) {
|
|
SmallVector<ProtocolConformance *, 2> conformances;
|
|
loader.first->loadAllConformances(next, loader.second, conformances);
|
|
loadAllConformances(next, conformances);
|
|
for (auto conf : conformances) {
|
|
protocols.push_back({conf->getProtocol(), SourceLoc()});
|
|
}
|
|
} else if (next->getParentSourceFile()) {
|
|
bool anyObject = false;
|
|
for (const auto &found :
|
|
getDirectlyInheritedNominalTypeDecls(next, anyObject)) {
|
|
if (auto proto = dyn_cast<ProtocolDecl>(found.Item))
|
|
protocols.push_back({proto, found.Loc});
|
|
}
|
|
}
|
|
|
|
extensionFunc(next, protocols);
|
|
}
|
|
}
|
|
|
|
void ConformanceLookupTable::inheritConformances(ClassDecl *classDecl,
|
|
ClassDecl *superclassDecl,
|
|
ExtensionDecl *superclassExt) {
|
|
// Local function to return the location of the superclass. This
|
|
// takes a little digging, so compute on first use and cache it.
|
|
SourceLoc superclassLoc;
|
|
auto getSuperclassLoc = [&] {
|
|
if (superclassLoc.isValid())
|
|
return superclassLoc;
|
|
|
|
for (const auto &inherited : classDecl->getInherited()) {
|
|
if (auto inheritedType = inherited.getType()) {
|
|
if (inheritedType->getClassOrBoundGenericClass()) {
|
|
superclassLoc = inherited.getSourceRange().Start;
|
|
return superclassLoc;
|
|
}
|
|
if (inheritedType->isExistentialType()) {
|
|
auto layout = inheritedType->getExistentialLayout();
|
|
if (layout.explicitSuperclass) {
|
|
superclassLoc = inherited.getSourceRange().Start;
|
|
return superclassLoc;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
superclassLoc = superclassDecl->getLoc();
|
|
return superclassLoc;
|
|
};
|
|
|
|
llvm::SmallPtrSet<ProtocolDecl *, 4> protocols;
|
|
auto addInheritedConformance = [&](ConformanceEntry *entry) {
|
|
auto protocol = entry->getProtocol();
|
|
|
|
// Don't add redundant conformances here. This is merely an
|
|
// optimization; resolveConformances() would zap the duplicates
|
|
// anyway.
|
|
if (!protocols.insert(protocol).second)
|
|
return;
|
|
|
|
// Add the inherited entry.
|
|
(void)addProtocol(protocol, getSuperclassLoc(),
|
|
ConformanceSource::forInherited(classDecl));
|
|
};
|
|
|
|
// Add inherited conformances.
|
|
DeclContext *superDC = superclassExt;
|
|
if (!superclassExt)
|
|
superDC = superclassDecl;
|
|
|
|
for (auto entry : superclassDecl->ConformanceTable->AllConformances[superDC]){
|
|
addInheritedConformance(entry);
|
|
}
|
|
}
|
|
|
|
void ConformanceLookupTable::updateLookupTable(NominalTypeDecl *nominal,
|
|
ConformanceStage stage) {
|
|
switch (stage) {
|
|
case ConformanceStage::RecordedExplicit:
|
|
// Record all of the explicit conformances.
|
|
forEachInStage(
|
|
stage, nominal,
|
|
[&](NominalTypeDecl *nominal) {
|
|
addInheritedProtocols(nominal,
|
|
ConformanceSource::forExplicit(nominal));
|
|
},
|
|
[&](ExtensionDecl *ext,
|
|
ArrayRef<ConformanceConstructionInfo> protos) {
|
|
// The extension decl may not be validated, so we can't use
|
|
// its inherited protocols directly.
|
|
auto source = ConformanceSource::forExplicit(ext);
|
|
for (auto locAndProto : protos)
|
|
addProtocol(locAndProto.Item, locAndProto.Loc, source);
|
|
});
|
|
break;
|
|
|
|
case ConformanceStage::Inherited:
|
|
updateLookupTable(nominal, ConformanceStage::RecordedExplicit);
|
|
|
|
// For classes, expand implied conformances of the superclass,
|
|
// because an implied conformance in the superclass is considered
|
|
// "fixed" in the subclass.
|
|
if (auto classDecl = dyn_cast<ClassDecl>(nominal)) {
|
|
if (auto superclassDecl = classDecl->getSuperclassDecl()) {
|
|
// Break infinite recursion when visiting ill-formed classes
|
|
// with circular inheritance.
|
|
if (VisitingSuperclass)
|
|
return;
|
|
llvm::SaveAndRestore<bool> visiting(VisitingSuperclass, true);
|
|
|
|
// Don't update our own lookup table if we inherit from ourselves.
|
|
if (classDecl == superclassDecl)
|
|
break;
|
|
|
|
// Resolve the conformances of the superclass.
|
|
superclassDecl->prepareConformanceTable();
|
|
superclassDecl->ConformanceTable->updateLookupTable(
|
|
superclassDecl,
|
|
ConformanceStage::Resolved);
|
|
|
|
// Expand inherited conformances from all superclasses.
|
|
// We may have circular inheritance in ill-formed classes, so keep an
|
|
// eye out for that.
|
|
auto circularSuperclass = superclassDecl->getSuperclassDecl();
|
|
|
|
do {
|
|
forEachInStage(
|
|
stage, superclassDecl,
|
|
[&](NominalTypeDecl *superclass) {
|
|
inheritConformances(classDecl, superclassDecl, nullptr);
|
|
},
|
|
[&](ExtensionDecl *ext,
|
|
ArrayRef<ConformanceConstructionInfo> protos) {
|
|
(void)protos;
|
|
inheritConformances(classDecl, superclassDecl, ext);
|
|
});
|
|
superclassDecl = superclassDecl->getSuperclassDecl();
|
|
if (circularSuperclass)
|
|
circularSuperclass = circularSuperclass->getSuperclassDecl();
|
|
if (circularSuperclass)
|
|
circularSuperclass = circularSuperclass->getSuperclassDecl();
|
|
} while (superclassDecl != circularSuperclass);
|
|
}
|
|
}
|
|
break;
|
|
|
|
case ConformanceStage::ExpandedImplied:
|
|
// Record explicit conformances and import inherited conformances
|
|
// before expanding.
|
|
updateLookupTable(nominal, ConformanceStage::Inherited);
|
|
|
|
// Expand inherited conformances.
|
|
forEachInStage(
|
|
stage, nominal,
|
|
[&](NominalTypeDecl *nominal) {
|
|
expandImpliedConformances(nominal, nominal);
|
|
},
|
|
[&](ExtensionDecl *ext,
|
|
ArrayRef<ConformanceConstructionInfo> protos) {
|
|
(void)protos;
|
|
expandImpliedConformances(nominal, ext);
|
|
});
|
|
break;
|
|
|
|
case ConformanceStage::Resolved:
|
|
// Expand inherited conformances so we have the complete set of
|
|
// conformances.
|
|
updateLookupTable(nominal, ConformanceStage::ExpandedImplied);
|
|
|
|
/// Determine whether any extensions were added that might require
|
|
/// us to compute conformances again.
|
|
bool anyChanged = false;
|
|
forEachInStage(stage, nominal,
|
|
[&](NominalTypeDecl *nominal) { anyChanged = true; },
|
|
[&](ExtensionDecl *ext,
|
|
ArrayRef<ConformanceConstructionInfo>) {
|
|
anyChanged = true;
|
|
});
|
|
|
|
if (anyChanged) {
|
|
// Compute the conformances for each protocol.
|
|
bool anySuperseded = false;
|
|
for (const auto &entry : Conformances) {
|
|
if (resolveConformances(entry.first))
|
|
anySuperseded = true;
|
|
}
|
|
|
|
if (anySuperseded) {
|
|
// Update the lists of all conformances to remove superseded
|
|
// conformances.
|
|
for (auto &conformances : AllConformances) {
|
|
conformances.second.erase(
|
|
std::remove_if(conformances.second.begin(),
|
|
conformances.second.end(),
|
|
[&](ConformanceEntry *entry) {
|
|
return entry->isSuperseded();
|
|
}),
|
|
conformances.second.end());
|
|
}
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
void ConformanceLookupTable::loadAllConformances(
|
|
DeclContext *dc,
|
|
ArrayRef<ProtocolConformance*> conformances) {
|
|
// If this declaration context came from source, there's nothing to
|
|
// do here.
|
|
if (dc->getParentSourceFile())
|
|
return;
|
|
|
|
// Add entries for each loaded conformance.
|
|
for (auto conformance : conformances) {
|
|
registerProtocolConformance(conformance);
|
|
}
|
|
}
|
|
|
|
bool ConformanceLookupTable::addProtocol(ProtocolDecl *protocol, SourceLoc loc,
|
|
ConformanceSource source) {
|
|
DeclContext *dc = source.getDeclContext();
|
|
ASTContext &ctx = dc->getASTContext();
|
|
|
|
// Determine the kind of conformance.
|
|
ConformanceEntryKind kind = source.getKind();
|
|
|
|
// If this entry is synthesized or implied, scan to determine
|
|
// whether there are any explicit better conformances that make this
|
|
// conformance trivially superseded (and, therefore, not worth
|
|
// recording).
|
|
auto &conformanceEntries = Conformances[protocol];
|
|
if (kind == ConformanceEntryKind::Implied ||
|
|
kind == ConformanceEntryKind::Synthesized) {
|
|
for (const auto *existingEntry : conformanceEntries) {
|
|
switch (existingEntry->getKind()) {
|
|
case ConformanceEntryKind::Explicit:
|
|
case ConformanceEntryKind::Inherited:
|
|
return false;
|
|
|
|
case ConformanceEntryKind::Implied:
|
|
// Ignore implied circular protocol inheritance
|
|
if (existingEntry->getDeclContext() == dc)
|
|
return false;
|
|
|
|
// An implied conformance is better than a synthesized one, unless
|
|
// the implied conformance was deserialized.
|
|
if (kind == ConformanceEntryKind::Synthesized &&
|
|
existingEntry->getDeclContext()->getParentSourceFile() == nullptr)
|
|
return false;
|
|
|
|
break;
|
|
|
|
case ConformanceEntryKind::Synthesized:
|
|
// An implied conformance is better unless it was deserialized.
|
|
if (dc->getParentSourceFile() == nullptr)
|
|
return false;
|
|
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Build the conformance entry (if it hasn't been built before).
|
|
ConformanceEntry *entry = new (ctx) ConformanceEntry(loc, protocol, source);
|
|
conformanceEntries.push_back(entry);
|
|
|
|
// Record this as a conformance within the given declaration
|
|
// context.
|
|
AllConformances[dc].push_back(entry);
|
|
|
|
return true;
|
|
}
|
|
|
|
void ConformanceLookupTable::addInheritedProtocols(
|
|
llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *> decl,
|
|
ConformanceSource source) {
|
|
// Find all of the protocols in the inheritance list.
|
|
bool anyObject = false;
|
|
for (const auto &found :
|
|
getDirectlyInheritedNominalTypeDecls(decl, anyObject)) {
|
|
if (auto proto = dyn_cast<ProtocolDecl>(found.Item))
|
|
addProtocol(proto, found.Loc, source);
|
|
}
|
|
}
|
|
|
|
void ConformanceLookupTable::expandImpliedConformances(NominalTypeDecl *nominal,
|
|
DeclContext *dc) {
|
|
// Note: recursive type-checking implies that AllConformances
|
|
// may be reallocated during this traversal, so pay the lookup cost
|
|
// during each iteration.
|
|
for (unsigned i = 0; i != AllConformances[dc].size(); ++i) {
|
|
/// FIXME: Avoid the possibility of an infinite loop by fixing the root
|
|
/// cause instead (incomplete circularity detection).
|
|
assert(i <= 16384 &&
|
|
"Infinite loop due to circular protocol inheritance?");
|
|
ConformanceEntry *conformanceEntry = AllConformances[dc][i];
|
|
ProtocolDecl *conformingProtocol = conformanceEntry->getProtocol();
|
|
|
|
// An @objc enum that explicitly conforms to the Error protocol
|
|
// also implicitly conforms to _ObjectiveCBridgeableError, via the
|
|
// known protocol _BridgedNSError.
|
|
if (conformingProtocol->isSpecificProtocol(
|
|
KnownProtocolKind::Error) &&
|
|
isa<EnumDecl>(nominal) && nominal->isObjC() &&
|
|
cast<EnumDecl>(nominal)->hasCases() &&
|
|
cast<EnumDecl>(nominal)->hasOnlyCasesWithoutAssociatedValues()) {
|
|
ASTContext &ctx = nominal->getASTContext();
|
|
if (auto bridgedNSError
|
|
= ctx.getProtocol(KnownProtocolKind::BridgedNSError)) {
|
|
addProtocol(bridgedNSError, SourceLoc(),
|
|
ConformanceSource::forImplied(conformanceEntry));
|
|
}
|
|
}
|
|
|
|
addInheritedProtocols(conformingProtocol,
|
|
ConformanceSource::forImplied(conformanceEntry));
|
|
}
|
|
}
|
|
|
|
/// Determine whether the given conformance entry kind can be replaced.
|
|
static bool isReplaceable(ConformanceEntryKind kind) {
|
|
switch (kind) {
|
|
case ConformanceEntryKind::Implied:
|
|
case ConformanceEntryKind::Synthesized:
|
|
return true;
|
|
|
|
case ConformanceEntryKind::Explicit:
|
|
case ConformanceEntryKind::Inherited:
|
|
return false;
|
|
}
|
|
|
|
llvm_unreachable("Unhandled ConformanceEntryKind in switch.");
|
|
}
|
|
|
|
ConformanceLookupTable::Ordering ConformanceLookupTable::compareConformances(
|
|
ConformanceEntry *lhs,
|
|
ConformanceEntry *rhs,
|
|
bool &diagnoseSuperseded) {
|
|
// If only one of the conformances is unconditionally available on the
|
|
// current deployment target, pick that one.
|
|
//
|
|
// FIXME: Conformance lookup should really depend on source location for
|
|
// this to be 100% correct.
|
|
if (lhs->getDeclContext()->isAlwaysAvailableConformanceContext() !=
|
|
rhs->getDeclContext()->isAlwaysAvailableConformanceContext()) {
|
|
return (lhs->getDeclContext()->isAlwaysAvailableConformanceContext()
|
|
? Ordering::Before
|
|
: Ordering::After);
|
|
}
|
|
|
|
// If one entry is fixed and the other is not, we have our answer.
|
|
if (lhs->isFixed() != rhs->isFixed()) {
|
|
// If the non-fixed conformance is not replaceable, we have a failure to
|
|
// diagnose.
|
|
diagnoseSuperseded = (lhs->isFixed() &&
|
|
!isReplaceable(rhs->getRankingKind())) ||
|
|
(rhs->isFixed() &&
|
|
!isReplaceable(lhs->getRankingKind()));
|
|
|
|
return lhs->isFixed() ? Ordering::Before : Ordering::After;
|
|
}
|
|
|
|
ConformanceEntryKind lhsKind = lhs->getRankingKind();
|
|
ConformanceEntryKind rhsKind = rhs->getRankingKind();
|
|
|
|
if (lhsKind != ConformanceEntryKind::Implied ||
|
|
rhsKind != ConformanceEntryKind::Implied) {
|
|
// If both conformances are non-replaceable, diagnose the
|
|
// superseded one.
|
|
diagnoseSuperseded = !isReplaceable(lhsKind) && !isReplaceable(rhsKind) &&
|
|
!(lhsKind == ConformanceEntryKind::Inherited &&
|
|
rhsKind == ConformanceEntryKind::Inherited);
|
|
|
|
// If we can order by kind, do so.
|
|
if (lhsKind != rhsKind) {
|
|
return (static_cast<unsigned>(lhsKind) < static_cast<unsigned>(rhsKind))
|
|
? Ordering::Before
|
|
: Ordering::After;
|
|
}
|
|
|
|
// We shouldn't get two synthesized conformances. It's not harmful
|
|
// per se, but it's indicative of redundant logic in the frontend.
|
|
assert((lhs->getKind() != ConformanceEntryKind::Synthesized ||
|
|
rhs->getKind() != ConformanceEntryKind::Synthesized) &&
|
|
"Shouldn't ever get two truly synthesized conformances");
|
|
|
|
// FIXME: Deterministic ordering.
|
|
return Ordering::Before;
|
|
}
|
|
|
|
// Both the left- and right-hand sides are implied, so determine where the
|
|
// conformance should go.
|
|
assert(lhsKind == ConformanceEntryKind::Implied &&
|
|
"Expected implied conformance");
|
|
assert(rhsKind == ConformanceEntryKind::Implied &&
|
|
"Expected implied conformance");
|
|
diagnoseSuperseded = false;
|
|
|
|
// First, try to use the stated explicit conformances to determine where the
|
|
// conformance should go.
|
|
auto lhsExplicit = lhs->getDeclaredConformance();
|
|
auto lhsExplicitProtocol = lhsExplicit->getProtocol();
|
|
auto rhsExplicit = rhs->getDeclaredConformance();
|
|
auto rhsExplicitProtocol = rhsExplicit->getProtocol();
|
|
if (lhsExplicitProtocol != rhsExplicitProtocol) {
|
|
// If the explicit protocol for the left-hand side is implied by
|
|
// the explicit protocol for the right-hand side, the left-hand
|
|
// side supersedes the right-hand side.
|
|
for (auto rhsProtocol : rhsExplicitProtocol->getAllProtocols()) {
|
|
if (rhsProtocol == lhsExplicitProtocol) {
|
|
return Ordering::Before;
|
|
}
|
|
}
|
|
|
|
// If the explicit protocol for the right-hand side is implied by
|
|
// the explicit protocol for the left-hand side, the right-hand
|
|
// side supersedes the left-hand side.
|
|
for (auto lhsProtocol : lhsExplicitProtocol->getAllProtocols()) {
|
|
if (lhsProtocol == rhsExplicitProtocol) {
|
|
return Ordering::After;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Prefer the least conditional implier, which we approximate by seeing if one
|
|
// of the contexts syntactically has no generic requirements. This misses
|
|
// redundant cases like `struct Foo<T: P> {} extension Foo: P where T: P {}`
|
|
// (Foo : P is unconditional), but isConstrainedExtension doesn't fly as it
|
|
// requires the generic signature of the extension to exist, which requires
|
|
// conformances to exist, which is what we're doing here.
|
|
auto hasAdditionalRequirements = [&](ConformanceEntry *entry) {
|
|
if (auto ED = dyn_cast<ExtensionDecl>(entry->getDeclContext()))
|
|
if (auto TWC = ED->getTrailingWhereClause())
|
|
return !TWC->getRequirements().empty();
|
|
|
|
return false;
|
|
};
|
|
bool lhsHasReqs = hasAdditionalRequirements(lhs);
|
|
bool rhsHasReqs = hasAdditionalRequirements(rhs);
|
|
if (lhsHasReqs != rhsHasReqs)
|
|
return lhsHasReqs ? Ordering::After : Ordering::Before;
|
|
|
|
// If the two conformances come from the same file, pick the first context
|
|
// in the file.
|
|
auto lhsSF = lhs->getDeclContext()->getParentSourceFile();
|
|
auto rhsSF = rhs->getDeclContext()->getParentSourceFile();
|
|
if (lhsSF && lhsSF == rhsSF) {
|
|
ASTContext &ctx = lhsSF->getASTContext();
|
|
return ctx.SourceMgr.isBeforeInBuffer(lhs->getDeclaredLoc(),
|
|
rhs->getDeclaredLoc())
|
|
? Ordering::Before
|
|
: Ordering::After;
|
|
}
|
|
|
|
// If one of the conformances comes from the same file as the type
|
|
// declaration, pick that one; this is so that conformance synthesis works if
|
|
// there's any implied conformance in the same file as the type.
|
|
auto NTD = lhs->getDeclContext()->getSelfNominalTypeDecl();
|
|
auto typeSF = NTD->getParentSourceFile();
|
|
if (typeSF) {
|
|
if (typeSF == lhsSF)
|
|
return Ordering::Before;
|
|
if (typeSF == rhsSF)
|
|
return Ordering::After;
|
|
}
|
|
|
|
// Otherwise, pick the earlier file unit.
|
|
auto lhsFileUnit
|
|
= dyn_cast<FileUnit>(lhs->getDeclContext()->getModuleScopeContext());
|
|
auto rhsFileUnit
|
|
= dyn_cast<FileUnit>(rhs->getDeclContext()->getModuleScopeContext());
|
|
assert(lhsFileUnit && rhsFileUnit && "Not from a file unit?");
|
|
if (lhsFileUnit == rhsFileUnit) {
|
|
// If the file units are the same, just pick arbitrarily; we're not
|
|
// actually emitting anything.
|
|
// FIXME: Only because we're synthesizing conformances for deserialized
|
|
// protocols. Once that's no longer true (because we're serializing
|
|
// everything appropriately in the module), we should assert that this
|
|
// does not happen.
|
|
assert(!lhsSF && !rhsSF && "Source files shouldn't conflict");
|
|
return Ordering::Before;
|
|
}
|
|
auto module = lhs->getDeclContext()->getParentModule();
|
|
assert(lhs->getDeclContext()->getParentModule()
|
|
== rhs->getDeclContext()->getParentModule() &&
|
|
"conformances should be in the same module");
|
|
for (auto file : module->getFiles()) {
|
|
if (file == lhsFileUnit)
|
|
return Ordering::Before;
|
|
if (file == rhsFileUnit)
|
|
return Ordering::After;
|
|
}
|
|
|
|
llvm_unreachable("files weren't in the parent module?");
|
|
}
|
|
|
|
bool ConformanceLookupTable::resolveConformances(ProtocolDecl *protocol) {
|
|
// Find any entries that are superseded by other entries.
|
|
ConformanceEntries &entries = Conformances[protocol];
|
|
llvm::SmallPtrSet<DeclContext *, 4> knownConformances;
|
|
bool anySuperseded = false;
|
|
for (auto entry : entries) {
|
|
// If this entry has a conformance associated with it, note that.
|
|
if (entry->getConformance())
|
|
knownConformances.insert(entry->getDeclContext());
|
|
|
|
// If this entry was superseded, move on.
|
|
if (entry->isSuperseded()) {
|
|
anySuperseded = true;
|
|
continue;
|
|
}
|
|
|
|
// Determine whether this entry is superseded by (or supersedes)
|
|
// some other entry.
|
|
for (auto otherEntry : entries) {
|
|
if (entry == otherEntry)
|
|
continue;
|
|
|
|
if (otherEntry->isSuperseded()) {
|
|
anySuperseded = true;
|
|
continue;
|
|
}
|
|
|
|
bool diagnoseSuperseded = false;
|
|
bool doneWithEntry = false;
|
|
switch (compareConformances(entry, otherEntry, diagnoseSuperseded)) {
|
|
case Ordering::Equivalent:
|
|
break;
|
|
|
|
case Ordering::Before:
|
|
otherEntry->markSupersededBy(*this, entry, diagnoseSuperseded);
|
|
anySuperseded = true;
|
|
break;
|
|
|
|
case Ordering::After:
|
|
entry->markSupersededBy(*this, otherEntry, diagnoseSuperseded);
|
|
anySuperseded = true;
|
|
doneWithEntry = true;
|
|
break;
|
|
}
|
|
|
|
if (doneWithEntry)
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If any entries were superseded, remove them now.
|
|
if (anySuperseded) {
|
|
entries.erase(std::remove_if(entries.begin(), entries.end(),
|
|
[&](ConformanceEntry *entry) {
|
|
return entry->isSuperseded();
|
|
}),
|
|
entries.end());
|
|
}
|
|
|
|
return anySuperseded;
|
|
}
|
|
|
|
DeclContext *ConformanceLookupTable::getConformingContext(
|
|
NominalTypeDecl *nominal,
|
|
ConformanceEntry *entry) {
|
|
ProtocolDecl *protocol = entry->getProtocol();
|
|
|
|
// Dig through the inherited entries to find a non-inherited one.
|
|
// Handle recursive inheritance.
|
|
SmallPtrSet<ClassDecl *, 4> visited;
|
|
while (entry->getKind() == ConformanceEntryKind::Inherited) {
|
|
// Make sure we have an up-to-date conformance table for the
|
|
// superclass.
|
|
auto classDecl = cast<ClassDecl>(nominal);
|
|
if (!visited.insert(classDecl).second)
|
|
return nullptr;
|
|
|
|
// If we had a circular dependency, the superclass may not exist.
|
|
auto superclassDecl
|
|
= classDecl->getSuperclassDecl();
|
|
|
|
if (!superclassDecl)
|
|
return nullptr;
|
|
|
|
if (!classDecl->ConformanceTable->VisitingSuperclass) {
|
|
llvm::SaveAndRestore<bool> visiting(
|
|
classDecl->ConformanceTable
|
|
->VisitingSuperclass,
|
|
true);
|
|
|
|
superclassDecl->prepareConformanceTable();
|
|
superclassDecl->ConformanceTable->resolveConformances(protocol);
|
|
}
|
|
|
|
// Grab the superclass entry and continue searching for a
|
|
// non-inherited conformance.
|
|
// FIXME: Ambiguity detection and resolution.
|
|
entry = superclassDecl->ConformanceTable->Conformances[protocol].front();
|
|
nominal = superclassDecl;
|
|
}
|
|
|
|
return entry->getDeclContext();
|
|
}
|
|
|
|
ProtocolConformance *
|
|
ConformanceLookupTable::getConformance(NominalTypeDecl *nominal,
|
|
ConformanceEntry *entry) {
|
|
// If we already have a conformance, we're done.
|
|
if (auto conformance = entry->getConformance())
|
|
return conformance;
|
|
|
|
ProtocolDecl *protocol = entry->getProtocol();
|
|
|
|
// Determine where the explicit conformance actually lives.
|
|
// FIXME: This is a hack to ensure that inherited conformances are
|
|
// always "single step", which is bad for resilience but is assumed
|
|
// elsewhere in the compiler.
|
|
DeclContext *conformingDC = getConformingContext(nominal, entry);
|
|
if (!conformingDC)
|
|
return nullptr;
|
|
|
|
auto *conformingNominal = conformingDC->getSelfNominalTypeDecl();
|
|
|
|
// Form the conformance.
|
|
Type type = entry->getDeclContext()->getDeclaredInterfaceType();
|
|
ASTContext &ctx = nominal->getASTContext();
|
|
if (entry->getKind() == ConformanceEntryKind::Inherited) {
|
|
// For an inherited conformance, the conforming nominal type will
|
|
// be different from the nominal type.
|
|
assert(conformingNominal != nominal && "Broken inherited conformance");
|
|
|
|
// Find the superclass type that matches where the conformance was
|
|
// declared.
|
|
auto *conformingClass = cast<ClassDecl>(conformingNominal);
|
|
Type superclassTy = type->getSuperclassForDecl(conformingClass);
|
|
if (superclassTy->is<ErrorType>())
|
|
return nullptr;
|
|
|
|
// Look up the inherited conformance.
|
|
ModuleDecl *module = entry->getDeclContext()->getParentModule();
|
|
auto inheritedConformance = module->lookupConformance(superclassTy,
|
|
protocol);
|
|
|
|
// Form the inherited conformance.
|
|
entry->Conformance =
|
|
ctx.getInheritedConformance(type, inheritedConformance.getConcrete());
|
|
} else {
|
|
// Create or find the normal conformance.
|
|
Type conformingType = conformingDC->getDeclaredInterfaceType();
|
|
SourceLoc conformanceLoc
|
|
= conformingNominal == conformingDC
|
|
? conformingNominal->getLoc()
|
|
: cast<ExtensionDecl>(conformingDC)->getLoc();
|
|
|
|
auto normalConf =
|
|
ctx.getConformance(conformingType, protocol, conformanceLoc,
|
|
conformingDC, ProtocolConformanceState::Incomplete);
|
|
// Invalid code may cause the getConformance call below to loop, so break
|
|
// the infinite recursion by setting this eagerly to shortcircuit with the
|
|
// early return at the start of this function.
|
|
entry->Conformance = normalConf;
|
|
|
|
NormalProtocolConformance *implyingConf = nullptr;
|
|
if (entry->Source.getKind() == ConformanceEntryKind::Implied) {
|
|
auto implyingEntry = entry->Source.getImpliedSource();
|
|
implyingConf = getConformance(conformingNominal, implyingEntry)
|
|
->getRootNormalConformance();
|
|
}
|
|
normalConf->setSourceKindAndImplyingConformance(entry->Source.getKind(),
|
|
implyingConf);
|
|
|
|
// If the conformance was synthesized by the ClangImporter, give it a
|
|
// lazy loader that will be used to populate the conformance.
|
|
|
|
// First, if this is a conformance to a base protocol of a derived
|
|
// protocol, find the most derived protocol.
|
|
auto *impliedEntry = entry;
|
|
while (impliedEntry->getKind() == ConformanceEntryKind::Implied)
|
|
impliedEntry = impliedEntry->Source.getImpliedSource();
|
|
|
|
// Check if this was a synthesized conformance.
|
|
if (impliedEntry->getKind() == ConformanceEntryKind::Synthesized) {
|
|
auto *impliedProto = impliedEntry->getProtocol();
|
|
|
|
// Find a SynthesizedProtocolAttr corresponding to the protocol.
|
|
for (auto attr : conformingNominal->getAttrs()
|
|
.getAttributes<SynthesizedProtocolAttr>()) {
|
|
auto otherProto = ctx.getProtocol(attr->getProtocolKind());
|
|
if (otherProto == impliedProto) {
|
|
// Set the conformance loader to the loader stashed inside
|
|
// the attribute.
|
|
normalConf->setLazyLoader(attr->getLazyLoader(), /*context=*/0);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return entry->Conformance.get<ProtocolConformance *>();
|
|
}
|
|
|
|
void ConformanceLookupTable::addSynthesizedConformance(NominalTypeDecl *nominal,
|
|
ProtocolDecl *protocol) {
|
|
addProtocol(protocol, nominal->getLoc(),
|
|
ConformanceSource::forSynthesized(nominal));
|
|
}
|
|
|
|
void ConformanceLookupTable::registerProtocolConformance(
|
|
ProtocolConformance *conformance,
|
|
bool synthesized) {
|
|
auto protocol = conformance->getProtocol();
|
|
auto dc = conformance->getDeclContext();
|
|
auto nominal = dc->getSelfNominalTypeDecl();
|
|
|
|
// If there is an entry to update, do so.
|
|
auto &dcConformances = AllConformances[dc];
|
|
for (auto entry : dcConformances) {
|
|
if (entry->getProtocol() == protocol) {
|
|
assert(!entry->getConformance() ||
|
|
entry->getConformance() == conformance &&
|
|
"Mismatched conformances");
|
|
entry->Conformance = conformance;
|
|
return;
|
|
}
|
|
}
|
|
|
|
// Otherwise, add a new entry.
|
|
auto inherited = dyn_cast<InheritedProtocolConformance>(conformance);
|
|
ConformanceSource source
|
|
= inherited ? ConformanceSource::forInherited(cast<ClassDecl>(nominal)) :
|
|
synthesized ? ConformanceSource::forSynthesized(nominal) :
|
|
ConformanceSource::forExplicit(dc);
|
|
|
|
ASTContext &ctx = nominal->getASTContext();
|
|
ConformanceEntry *entry = new (ctx) ConformanceEntry(SourceLoc(),
|
|
protocol,
|
|
source);
|
|
entry->Conformance = conformance;
|
|
|
|
// Record that this type conforms to the given protocol.
|
|
Conformances[protocol].push_back(entry);
|
|
|
|
// Record this as a conformance within the given declaration
|
|
// context.
|
|
dcConformances.push_back(entry);
|
|
}
|
|
|
|
bool ConformanceLookupTable::lookupConformance(
|
|
ModuleDecl *module,
|
|
NominalTypeDecl *nominal,
|
|
ProtocolDecl *protocol,
|
|
SmallVectorImpl<ProtocolConformance *> &conformances) {
|
|
// Update to record all explicit and inherited conformances.
|
|
updateLookupTable(nominal, ConformanceStage::Inherited);
|
|
|
|
// Look for conformances to this protocol.
|
|
auto known = Conformances.find(protocol);
|
|
if (known == Conformances.end()) {
|
|
// If we didn't find anything, expand implied conformances.
|
|
updateLookupTable(nominal, ConformanceStage::ExpandedImplied);
|
|
known = Conformances.find(protocol);
|
|
|
|
// We didn't find anything.
|
|
if (known == Conformances.end())
|
|
return false;
|
|
}
|
|
|
|
// Resolve the conformances for this protocol.
|
|
resolveConformances(protocol);
|
|
for (auto entry : Conformances[protocol]) {
|
|
if (auto conformance = getConformance(nominal, entry)) {
|
|
conformances.push_back(conformance);
|
|
}
|
|
}
|
|
return !conformances.empty();
|
|
}
|
|
|
|
void ConformanceLookupTable::lookupConformances(
|
|
NominalTypeDecl *nominal,
|
|
DeclContext *dc,
|
|
std::vector<ProtocolConformance *> *conformances,
|
|
SmallVectorImpl<ConformanceDiagnostic> *diagnostics) {
|
|
// We need to expand all implied conformances before we can find
|
|
// those conformances that pertain to this declaration context.
|
|
updateLookupTable(nominal, ConformanceStage::ExpandedImplied);
|
|
|
|
/// Resolve conformances for each of the protocols to which this
|
|
/// declaration may provide a conformance. Only some of these will
|
|
/// result in conformances that are attributed to this declaration
|
|
/// context.
|
|
auto &potentialConformances = AllConformances[dc];
|
|
for (const auto &potential : potentialConformances) {
|
|
resolveConformances(potential->getProtocol());
|
|
}
|
|
|
|
// Remove any superseded conformances from AllConformances.
|
|
potentialConformances.erase(
|
|
std::remove_if(potentialConformances.begin(),
|
|
potentialConformances.end(),
|
|
[&](ConformanceEntry *entry) {
|
|
if (entry->isSuperseded())
|
|
return true;
|
|
|
|
// Record the conformance.
|
|
if (conformances) {
|
|
if (auto conformance = getConformance(nominal, entry))
|
|
conformances->push_back(conformance);
|
|
}
|
|
return false;
|
|
}),
|
|
potentialConformances.end());
|
|
|
|
// Gather any diagnostics we've produced.
|
|
if (diagnostics) {
|
|
auto knownDiags = AllSupersededDiagnostics.find(dc);
|
|
if (knownDiags != AllSupersededDiagnostics.end()) {
|
|
for (const auto *entry : knownDiags->second) {
|
|
ConformanceEntry *supersededBy = entry->getSupersededBy();
|
|
|
|
diagnostics->push_back({entry->getProtocol(),
|
|
entry->getDeclaredLoc(),
|
|
entry->getKind(),
|
|
entry->getDeclaredConformance()->getProtocol(),
|
|
supersededBy->getDeclContext(),
|
|
supersededBy->getKind(),
|
|
supersededBy->getDeclaredConformance()
|
|
->getProtocol()});
|
|
}
|
|
|
|
// We have transferred these diagnostics; erase them.
|
|
AllSupersededDiagnostics.erase(knownDiags);
|
|
}
|
|
}
|
|
}
|
|
|
|
void ConformanceLookupTable::getAllProtocols(
|
|
NominalTypeDecl *nominal,
|
|
SmallVectorImpl<ProtocolDecl *> &scratch) {
|
|
// We need to expand all implied conformances to find the complete
|
|
// set of protocols to which this nominal type conforms.
|
|
updateLookupTable(nominal, ConformanceStage::ExpandedImplied);
|
|
|
|
// Gather all of the protocols.
|
|
for (const auto &conformance : Conformances) {
|
|
if (conformance.second.empty())
|
|
continue;
|
|
|
|
scratch.push_back(conformance.first);
|
|
}
|
|
|
|
// FIXME: sort the protocols in some canonical order?
|
|
}
|
|
|
|
int ConformanceLookupTable::compareProtocolConformances(
|
|
ProtocolConformance * const *lhsPtr,
|
|
ProtocolConformance * const *rhsPtr) {
|
|
ProtocolConformance *lhs = *lhsPtr;
|
|
ProtocolConformance *rhs = *rhsPtr;
|
|
|
|
// If the two conformances are normal conformances with locations,
|
|
// sort by location.
|
|
if (auto lhsNormal = dyn_cast<NormalProtocolConformance>(lhs)) {
|
|
if (auto rhsNormal = dyn_cast<NormalProtocolConformance>(rhs)) {
|
|
if (lhsNormal->getLoc().isValid() && rhsNormal->getLoc().isValid()) {
|
|
ASTContext &ctx = lhs->getDeclContext()->getASTContext();
|
|
unsigned lhsBuffer
|
|
= ctx.SourceMgr.findBufferContainingLoc(lhsNormal->getLoc());
|
|
unsigned rhsBuffer
|
|
= ctx.SourceMgr.findBufferContainingLoc(rhsNormal->getLoc());
|
|
|
|
// If the buffers are the same, use source location ordering.
|
|
if (lhsBuffer == rhsBuffer) {
|
|
return ctx.SourceMgr.isBeforeInBuffer(lhsNormal->getLoc(),
|
|
rhsNormal->getLoc());
|
|
}
|
|
|
|
// Otherwise, order by buffer identifier.
|
|
return ctx.SourceMgr.getIdentifierForBuffer(lhsBuffer)
|
|
.compare(ctx.SourceMgr.getIdentifierForBuffer(rhsBuffer));
|
|
}
|
|
}
|
|
}
|
|
|
|
// Otherwise, sort by protocol.
|
|
ProtocolDecl *lhsProto = lhs->getProtocol();
|
|
ProtocolDecl *rhsProto = rhs->getProtocol();
|
|
return TypeDecl::compare(lhsProto, rhsProto);
|
|
}
|
|
|
|
void ConformanceLookupTable::getAllConformances(
|
|
NominalTypeDecl *nominal,
|
|
bool sorted,
|
|
SmallVectorImpl<ProtocolConformance *> &scratch) {
|
|
// We need to expand and resolve all conformances to enumerate them.
|
|
updateLookupTable(nominal, ConformanceStage::Resolved);
|
|
|
|
// Gather all of the protocols.
|
|
for (const auto &conformance : AllConformances) {
|
|
for (auto entry : conformance.second) {
|
|
if (auto conformance = getConformance(nominal, entry))
|
|
scratch.push_back(conformance);
|
|
}
|
|
}
|
|
|
|
// If requested, sort the results.
|
|
if (sorted) {
|
|
llvm::array_pod_sort(scratch.begin(), scratch.end(),
|
|
&compareProtocolConformances);
|
|
}
|
|
}
|
|
|
|
void ConformanceLookupTable::getImplicitProtocols(
|
|
NominalTypeDecl *nominal,
|
|
SmallVectorImpl<ProtocolDecl *> &protocols) {
|
|
for (auto conformance : AllConformances[nominal]) {
|
|
if (conformance->getKind() == ConformanceEntryKind::Synthesized) {
|
|
protocols.push_back(conformance->getProtocol());
|
|
}
|
|
}
|
|
}
|
|
|
|
ArrayRef<ValueDecl *>
|
|
ConformanceLookupTable::getSatisfiedProtocolRequirementsForMember(
|
|
const ValueDecl *member,
|
|
NominalTypeDecl *nominal,
|
|
bool sorted) {
|
|
auto It = ConformingDeclMap.find(member);
|
|
if (It != ConformingDeclMap.end())
|
|
return It->second;
|
|
|
|
SmallVector<ProtocolConformance *, 4> result;
|
|
getAllConformances(nominal, sorted, result);
|
|
|
|
auto &reqs = ConformingDeclMap[member];
|
|
if (isa<TypeDecl>(member)) {
|
|
for (auto *conf : result) {
|
|
if (conf->isInvalid())
|
|
continue;
|
|
|
|
conf->forEachTypeWitness([&](const AssociatedTypeDecl *assoc,
|
|
Type type,
|
|
TypeDecl *typeDecl) -> bool {
|
|
if (typeDecl == member)
|
|
reqs.push_back(const_cast<AssociatedTypeDecl*>(assoc));
|
|
return false;
|
|
});
|
|
}
|
|
} else {
|
|
for (auto *conf : result) {
|
|
if (conf->isInvalid())
|
|
continue;
|
|
|
|
auto root = conf->getRootConformance();
|
|
root->forEachValueWitness([&](ValueDecl *req, Witness witness) {
|
|
if (witness.getDecl() == member)
|
|
reqs.push_back(req);
|
|
});
|
|
}
|
|
}
|
|
|
|
return reqs;
|
|
}
|
|
|
|
void ConformanceLookupTable::dump() const {
|
|
dump(llvm::errs());
|
|
}
|
|
|
|
void ConformanceLookupTable::dump(raw_ostream &os) const {
|
|
for (const auto &dcEntries : AllConformances) {
|
|
os << "Conformances in context:\n";
|
|
dcEntries.first->printContext(os);
|
|
for (auto entry : dcEntries.second) {
|
|
entry->dump(os);
|
|
}
|
|
}
|
|
}
|
|
|