TBDGen: Refactor symbol enumeration into SIL and IRGen utilities

include/swift/IRGen/IRSymbolVisitor.h

@@ -0,0 +1,79 @@
+//===--- IRSymbolVisitor.h - Symbol Visitor for IR --------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_IRGEN_IRSYMBOLVISITOR_H
+#define SWIFT_IRGEN_IRSYMBOLVISITOR_H
+
+#include "swift/IRGen/Linking.h"
+
+namespace swift {
+
+class SILSymbolVisitorContext;
+
+namespace irgen {
+
+/// Context for symbol enumeration using `IRSymbolVisitor`.
+class IRSymbolVisitorContext {
+  const UniversalLinkageInfo &LinkInfo;
+  const SILSymbolVisitorContext &SILCtx;
+
+public:
+  IRSymbolVisitorContext(const UniversalLinkageInfo &LinkInfo,
+                         const SILSymbolVisitorContext &SILCtx)
+      : LinkInfo{LinkInfo}, SILCtx{SILCtx} {}
+
+  const UniversalLinkageInfo &getLinkInfo() const { return LinkInfo; }
+  const SILSymbolVisitorContext &getSILCtx() const { return SILCtx; }
+};
+
+/// A visitor class which may be used to enumerate the entities representing
+/// linker symbols associated with a Swift declaration, file, or module. This
+/// class is a refinement of `SILSymbolVisitor` for the IRGen layer. Most of the
+/// enumerated linker symbols can be represented as either a `SILDeclRef` or a
+/// `LinkEntity`, but a few aren't supported by those abstractions and are
+/// handled ad-hoc. Additionally, there are some Obj-C entities (like methods)
+/// that don't actually have associated linker symbols but are enumerated for
+/// the convenience of clients using this utility for API surface discovery.
+class IRSymbolVisitor {
+public:
+  virtual ~IRSymbolVisitor() {}
+
+  /// Enumerate the symbols associated with the given decl.
+  void visit(Decl *D, const IRSymbolVisitorContext &ctx);
+
+  /// Enumerate the symbols associated with the given file.
+  void visitFile(FileUnit *file, const IRSymbolVisitorContext &ctx);
+
+  /// Enumerate the symbols associated with the given modules.
+  void visitModules(llvm::SmallVector<ModuleDecl *, 4> &modules,
+                    const IRSymbolVisitorContext &ctx);
+
+  /// Override to prepare for enumeration of the symbols for a specific decl.
+  virtual void willVisitDecl(Decl *D) {}
+
+  /// Override to clean up after enumeration of the symbols for a specific decl.
+  virtual void didVisitDecl(Decl *D) {}
+
+  virtual void addFunction(SILDeclRef declRef) {}
+  virtual void addFunction(StringRef name, SILDeclRef declRef) {}
+  virtual void addGlobalVar(VarDecl *VD) {}
+  virtual void addLinkEntity(LinkEntity entity) {}
+  virtual void addObjCInterface(ClassDecl *CD) {}
+  virtual void addObjCMethod(AbstractFunctionDecl *AFD) {}
+  virtual void addProtocolWitnessThunk(RootProtocolConformance *C,
+                                       ValueDecl *requirementDecl) {}
+};
+
+} // end namespace irgen
+} // end namespace swift
+
+#endif

include/swift/SIL/SILSymbolVisitor.h

@@ -0,0 +1,131 @@
+//===--- SILSymbolVisitor.h - Symbol Visitor for SIL ------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2022 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SWIFT_SIL_SILSYMBOLVISITOR_H
+#define SWIFT_SIL_SILSYMBOLVISITOR_H
+
+#include "swift/AST/Decl.h"
+#include "swift/AST/ProtocolAssociations.h"
+#include "swift/AST/ProtocolConformance.h"
+#include "swift/SIL/SILDeclRef.h"
+
+namespace swift {
+
+/// Options dictating which symbols are enumerated by `SILSymbolVisitor`.
+struct SILSymbolVisitorOptions {
+  /// Whether to visit the members of declarations like structs, classes, and
+  /// protocols.
+  bool VisitMembers = true;
+
+  /// Whether to only visit declarations for which linker directive symbols
+  /// are needed (e.g. decls with `@_originallyDefinedIn`.
+  bool LinkerDirectivesOnly = false;
+
+  /// Whether to only visit symbols with public linkage.
+  bool PublicSymbolsOnly = true;
+
+  /// Whether LLVM IR Virtual Function Elimination is enabled.
+  bool VirtualFunctionElimination = false;
+
+  /// Whether LLVM IR Witness Method Elimination is enabled.
+  bool WitnessMethodElimination = false;
+};
+
+/// Context for `SILSymbolVisitor` symbol enumeration.
+class SILSymbolVisitorContext {
+  ModuleDecl *Module;
+  const SILSymbolVisitorOptions Opts;
+
+public:
+  SILSymbolVisitorContext(ModuleDecl *M, const SILSymbolVisitorOptions Opts)
+      : Module{M}, Opts{Opts} {
+    assert(M);
+  };
+
+  ModuleDecl *getModule() const { return Module; }
+  const SILSymbolVisitorOptions &getOpts() const { return Opts; }
+};
+
+/// A visitor class which may be used to enumerate the entities representing
+/// linker symbols associated with a Swift declaration, file, or module. Some
+/// enumerated linker symbols can be represented as a `SILDeclRef`. The rest are
+/// enumerated ad-hoc. Additionally, there a some Obj-C entities (like methods)
+/// that don't actually have associated linker symbols but are enumerated for
+/// the convenience of clients using this utility for API surface discovery.
+class SILSymbolVisitor {
+public:
+  virtual ~SILSymbolVisitor() {}
+
+  /// Enumerate the symbols associated with the given decl.
+  void visitDecl(Decl *D, const SILSymbolVisitorContext &ctx);
+
+  /// Enumerate the symbols associated with the given file.
+  void visitFile(FileUnit *file, const SILSymbolVisitorContext &ctx);
+
+  /// Enumerate the symbols associated with the given modules.
+  void visitModules(llvm::SmallVector<ModuleDecl *, 4> &modules,
+                    const SILSymbolVisitorContext &ctx);
+
+  /// Override to prepare for enumeration of the symbols for a specific decl.
+  virtual void willVisitDecl(Decl *D) {}
+
+  /// Override to clean up after enumeration of the symbols for a specific decl.
+  virtual void didVisitDecl(Decl *D) {}
+
+  /// A classification for the dynamic dispatch metadata of a decl.
+  enum class DynamicKind {
+    /// May be replaced at runtime (e.g.`dynamic`).
+    Replaceable,
+
+    /// May replace another decl at runtime (e.g. `@_dynamicReplacement(for:)`).
+    Replacement,
+  };
+
+  virtual void addAssociatedConformanceDescriptor(AssociatedConformance AC) {}
+  virtual void addAssociatedTypeDescriptor(AssociatedTypeDecl *ATD) {}
+  virtual void addAsyncFunctionPointer(SILDeclRef declRef) {}
+  virtual void addBaseConformanceDescriptor(BaseConformance BC) {}
+  virtual void addClassMetadataBaseOffset(ClassDecl *CD) {}
+  virtual void addDispatchThunk(SILDeclRef declRef) {}
+  virtual void addDynamicFunction(AbstractFunctionDecl *AFD,
+                                  DynamicKind dynKind) {}
+  virtual void addEnumCase(EnumElementDecl *EED) {}
+  virtual void addFieldOffset(VarDecl *VD) {}
+  virtual void addFunction(SILDeclRef declRef) {}
+  virtual void addFunction(StringRef name, SILDeclRef declRef) {}
+  virtual void addGlobalVar(VarDecl *VD) {}
+  virtual void addMethodDescriptor(SILDeclRef declRef) {}
+  virtual void addMethodLookupFunction(ClassDecl *CD) {}
+  virtual void addNominalTypeDescriptor(NominalTypeDecl *NTD) {}
+  virtual void addObjCClass(ClassDecl *CD) {}
+  virtual void addObjCInterface(ClassDecl *CD) {}
+  virtual void addObjCMetaclass(ClassDecl *CD) {}
+  virtual void addObjCMethod(AbstractFunctionDecl *AFD) {}
+  virtual void addObjCResilientClassStub(ClassDecl *CD) {}
+  virtual void addOpaqueTypeDescriptor(OpaqueTypeDecl *OTD) {}
+  virtual void addOpaqueTypeDescriptorAccessor(OpaqueTypeDecl *OTD,
+                                               DynamicKind dynKind) {}
+  virtual void addPropertyDescriptor(AbstractStorageDecl *ASD) {}
+  virtual void addProtocolConformanceDescriptor(RootProtocolConformance *C) {}
+  virtual void addProtocolDescriptor(ProtocolDecl *PD) {}
+  virtual void addProtocolRequirementsBaseDescriptor(ProtocolDecl *PD) {}
+  virtual void addProtocolWitnessTable(RootProtocolConformance *C) {}
+  virtual void addProtocolWitnessThunk(RootProtocolConformance *C,
+                                       ValueDecl *requirementDecl) {}
+  virtual void addSwiftMetaclassStub(ClassDecl *CD) {}
+  virtual void addTypeMetadataAccessFunction(CanType T) {}
+  virtual void addTypeMetadataAddress(CanType T) {}
+};
+
+} // end namespace swift
+
+#endif

lib/IRGen/CMakeLists.txt

@@ -50,6 +50,7 @@ add_swift_host_library(swiftIRGen STATIC
   IRGenSILPasses.cpp
   IRGenRequests.cpp
   IRGenSIL.cpp
+  IRSymbolVisitor.cpp
   Linking.cpp
   LoadableByAddress.cpp
   LocalTypeData.cpp