Files
swift-mirror/include/swift/Sema/SourceLoader.h
Allan Shortlidge bbf189c8ab AST: Make the versioned variants of #if canImport() more reliable and consistent.
Previously, when evaluating a `#if canImport(Module, _version: 42)` directive the compiler could diagnose and ignore the directive under the following conditions:

- The associated binary module is corrupt/bogus.
- The .tbd for an underlying Clang module is missing a current-version field.

This behavior is surprising when there is a valid `.swiftinterface` available and it only becomes apparent when building against an SDK with an old enough version of the module that the version in the `.swiftinterface` is too low, making this failure easy to miss. Some modules have different versioning systems for their Swift and Clang modules and it can also be intentional for a distributed binary `.swiftmodule` to contain bogus data (to force the compiler to recompile the `.swiftinterface`) so we need to handle both of these cases gracefully and predictably.

Now the compiler will enumerate all module loaders, ask each of them to attempt to parse the module version and then consistently use the parsed version from a single source. The `.swiftinterface` is preferred if present, then the binary module if present, and then finally the `.tbd`. The `.tbd` is still always used exclusively for the `_underlyingVersion` variant of `canImport()`.

Resolves rdar://88723492
2022-09-07 14:18:05 -07:00

105 lines
3.6 KiB
C++

//===--- SourceLoader.h - Import .swift files as modules --------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_SEMA_SOURCELOADER_H
#define SWIFT_SEMA_SOURCELOADER_H
#include "swift/AST/ModuleLoader.h"
namespace swift {
class ASTContext;
class ModuleDecl;
/// Imports serialized Swift modules into an ASTContext.
class SourceLoader : public ModuleLoader {
private:
ASTContext &Ctx;
bool EnableLibraryEvolution;
explicit SourceLoader(ASTContext &ctx,
bool enableResilience,
DependencyTracker *tracker)
: ModuleLoader(tracker), Ctx(ctx),
EnableLibraryEvolution(enableResilience) {}
public:
static std::unique_ptr<SourceLoader>
create(ASTContext &ctx, bool enableResilience,
DependencyTracker *tracker = nullptr) {
return std::unique_ptr<SourceLoader>{
new SourceLoader(ctx, enableResilience, tracker)
};
}
SourceLoader(const SourceLoader &) = delete;
SourceLoader(SourceLoader &&) = delete;
SourceLoader &operator=(const SourceLoader &) = delete;
SourceLoader &operator=(SourceLoader &&) = delete;
/// Append visible module names to \p names. Note that names are possibly
/// duplicated, and not guaranteed to be ordered in any way.
void collectVisibleTopLevelModuleNames(
SmallVectorImpl<Identifier> &names) const override;
/// Check whether the module with a given name can be imported without
/// importing it.
///
/// Note that even if this check succeeds, errors may still occur if the
/// module is loaded in full.
///
/// If a non-null \p versionInfo is provided, the module version will be
/// parsed and populated.
virtual bool canImportModule(ImportPath::Module named,
ModuleVersionInfo *versionInfo) override;
/// Import a module with the given module path.
///
/// \param importLoc The location of the 'import' keyword.
///
/// \param path A sequence of (identifier, location) pairs that denote
/// the dotted module name to load, e.g., AppKit.NSWindow.
///
/// \returns the module referenced, if it could be loaded. Otherwise,
/// returns NULL.
virtual ModuleDecl *
loadModule(SourceLoc importLoc,
ImportPath::Module path) override;
/// Load extensions to the given nominal type.
///
/// \param nominal The nominal type whose extensions should be loaded.
///
/// \param previousGeneration The previous generation number. The AST already
/// contains extensions loaded from any generation up to and including this
/// one.
virtual void loadExtensions(NominalTypeDecl *nominal,
unsigned previousGeneration) override;
virtual void loadObjCMethods(
NominalTypeDecl *typeDecl,
ObjCSelector selector,
bool isInstanceMethod,
unsigned previousGeneration,
llvm::TinyPtrVector<AbstractFunctionDecl *> &methods) override
{
// Parsing populates the Objective-C method tables.
}
Optional<ModuleDependencies>
getModuleDependencies(StringRef moduleName, ModuleDependenciesCache &cache,
InterfaceSubContextDelegate &delegate) override;
};
}
#endif