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c47cd7a107
Existing code does not visit such declarations and does not mark them to be preserved in the binary even if not public and used. Resolves rdar://127903662
117 lines
4.5 KiB
C++
117 lines
4.5 KiB
C++
//===--- AlwaysEmitConformanceMetadataPreservation.cpp -------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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///
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/// Some frameworks may rely on conformances to protocols they provide
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/// to be present in binary product they are compiled into even if
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/// such conformances are not otherwise referenced in user code.
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/// Such conformances may then, for example, be queried and used by the
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/// runtime.
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///
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/// The developer may not ever explicitly reference or instantiate this type in
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/// their code, as it is effectively defining an XPC endpoint. However, when
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/// optimizations are enabled, the type may be stripped from the binary as it is
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/// never referenced. `@_alwaysEmitConformanceMetadata` can be used to mark
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/// a protocol to ensure that its conformances are always marked as externally
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/// visible even if not `public` to ensure they do not get optimized away.
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/// This mandatory pass makes it so.
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///
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//===----------------------------------------------------------------------===//
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#include "swift/AST/Attr.h"
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#define DEBUG_TYPE "always-emit-conformance-metadata-preservation"
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#include "swift/AST/ASTWalker.h"
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#include "swift/AST/NameLookup.h"
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#include "swift/AST/ProtocolConformance.h"
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#include "swift/AST/SourceFile.h"
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#include "swift/SIL/SILModule.h"
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#include "swift/SILOptimizer/PassManager/Passes.h"
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#include "swift/SILOptimizer/PassManager/Transforms.h"
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using namespace swift;
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namespace {
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/// A helper class to collect all nominal type declarations that conform to
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/// `@_alwaysEmitConformanceMetadata` protocols.
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class AlwaysEmitMetadataConformanceCollector : public ASTWalker {
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std::vector<NominalTypeDecl *> &AlwaysEmitMetadataConformanceDecls;
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public:
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AlwaysEmitMetadataConformanceCollector(
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std::vector<NominalTypeDecl *> &AlwaysEmitMetadataConformanceDecls)
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: AlwaysEmitMetadataConformanceDecls(AlwaysEmitMetadataConformanceDecls) {
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}
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PreWalkAction walkToDeclPre(Decl *D) override {
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auto hasAlwaysEmitMetadataConformance =
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[&](llvm::PointerUnion<const TypeDecl *, const ExtensionDecl *> Decl) {
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bool anyObject = false;
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InvertibleProtocolSet Inverses;
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for (const auto &found :
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getDirectlyInheritedNominalTypeDecls(Decl, Inverses, anyObject))
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if (auto Protocol = dyn_cast<ProtocolDecl>(found.Item))
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if (Protocol->getAttrs()
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.hasAttribute<AlwaysEmitConformanceMetadataAttr>())
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return true;
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return false;
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};
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if (auto *NTD = dyn_cast<NominalTypeDecl>(D)) {
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if (hasAlwaysEmitMetadataConformance(NTD))
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AlwaysEmitMetadataConformanceDecls.push_back(NTD);
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} else if (auto *ETD = dyn_cast<ExtensionDecl>(D)) {
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if (hasAlwaysEmitMetadataConformance(ETD))
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AlwaysEmitMetadataConformanceDecls.push_back(ETD->getExtendedNominal());
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}
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// Visit peers expanded from macros
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D->visitAuxiliaryDecls([&](Decl *decl) { decl->walk(*this); },
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/*visitFreestandingExpanded=*/false);
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return Action::Continue();
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}
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};
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class AlwaysEmitConformanceMetadataPreservation : public SILModuleTransform {
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void run() override {
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auto &M = *getModule();
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std::vector<NominalTypeDecl *> AlwaysEmitMetadataConformanceDecls;
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AlwaysEmitMetadataConformanceCollector Walker(
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AlwaysEmitMetadataConformanceDecls);
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SmallVector<Decl *> TopLevelDecls;
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if (M.getSwiftModule()->isMainModule()) {
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if (M.isWholeModule()) {
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for (const auto File : M.getSwiftModule()->getFiles())
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File->getTopLevelDecls(TopLevelDecls);
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} else {
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for (const auto Primary : M.getSwiftModule()->getPrimarySourceFiles()) {
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Primary->getTopLevelDecls(TopLevelDecls);
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// Visit macro expanded extensions
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if (auto *synthesizedPrimary = Primary->getSynthesizedFile())
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synthesizedPrimary->getTopLevelDecls(TopLevelDecls);
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}
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}
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}
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for (auto *TLD : TopLevelDecls)
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TLD->walk(Walker);
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for (auto &NTD : AlwaysEmitMetadataConformanceDecls)
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M.addExternallyVisibleDecl(NTD);
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}
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};
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} // end anonymous namespace
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SILTransform *swift::createAlwaysEmitConformanceMetadataPreservation() {
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return new AlwaysEmitConformanceMetadataPreservation();
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}
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