text: //===--- LangOptions.h - Language & configuration options -------*- C++ -*-===//
  //
  // This source file is part of the Swift.org open source project
  //
  // Copyright (c) 2014 - 2018 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 defines the LangOptions class, which provides various
  //  language and configuration flags.
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef SWIFT_BASIC_LANGOPTIONS_H
  #define SWIFT_BASIC_LANGOPTIONS_H
  
  #include "swift/Config.h"
  #include "swift/Basic/CycleDiagnosticKind.h"
  #include "swift/Basic/LLVM.h"
  #include "swift/Basic/Version.h"
  #include "llvm/ADT/ArrayRef.h"
  #include "llvm/ADT/Hashing.h"
  #include "llvm/ADT/SmallVector.h"
  #include "llvm/ADT/StringRef.h"
  #include "llvm/ADT/SmallString.h"
  #include "llvm/ADT/Triple.h"
  #include "llvm/Support/Regex.h"
  #include "llvm/Support/raw_ostream.h"
  #include "llvm/Support/VersionTuple.h"
  #include <string>
  #include <vector>
  
  namespace swift {
  
    /// Kind of implicit platform conditions.
    enum class PlatformConditionKind {
      /// The active os target (OSX, iOS, Linux, etc.)
      OS,
      /// The active arch target (x86_64, i386, arm, arm64, etc.)
      Arch,
      /// The active endianness target (big or little)
      Endianness,
      /// Runtime support (_ObjC or _Native)
      Runtime,
      /// Conditional import of module
      CanImport,
      /// Target Environment (currently just 'simulator' or absent)
      TargetEnvironment,
    };
  
    /// Describes which Swift 3 Objective-C inference warnings should be
    /// emitted.
    enum class Swift3ObjCInferenceWarnings {
      /// No warnings; this is the default.
      None,
      /// "Minimal" warnings driven by uses of declarations that make use of
      /// the Objective-C entry point directly.
      Minimal,
      /// "Complete" warnings that add "@objc" for every entry point that
      /// Swift 3 would have inferred as "@objc" but Swift 4 will not.
      Complete,
    };
  
    /// \brief A collection of options that affect the language dialect and
    /// provide compiler debugging facilities.
    class LangOptions {
    public:
  
      /// \brief The target we are building for.
      ///
      /// This represents the minimum deployment target.
      llvm::Triple Target;
  
      ///
      /// Language features
      ///
  
      /// \brief User-overridable language version to compile for.
      version::Version EffectiveLanguageVersion = version::Version::getCurrentLanguageVersion();
  
      /// \brief Disable API availability checking.
      bool DisableAvailabilityChecking = false;
  
      /// \brief Maximum number of typo corrections we are allowed to perform.
      unsigned TypoCorrectionLimit = 10;
      
      /// Should access control be respected?
      bool EnableAccessControl = true;
  
      /// Enable 'availability' restrictions for App Extensions.
      bool EnableAppExtensionRestrictions = false;
  
      ///
      /// Support for alternate usage modes
      ///
  
      /// \brief Enable features useful for running in the debugger.
      bool DebuggerSupport = false;
  
      /// Allows using identifiers with a leading dollar.
      bool EnableDollarIdentifiers = false;
  
      /// \brief Allow throwing call expressions without annotation with 'try'.
      bool EnableThrowWithoutTry = false;
  
      /// \brief Enable features useful for running playgrounds.
      // FIXME: This should probably be limited to the particular SourceFile.
      bool Playground = false;
  
      /// \brief Keep comments during lexing and attach them to declarations.
      bool AttachCommentsToDecls = false;
  
      /// Whether to include initializers when code-completing a postfix
      /// expression.
      bool CodeCompleteInitsInPostfixExpr = false;
  
      /// Whether to use heuristics to decide whether to show call-pattern
      /// completions.
      bool CodeCompleteCallPatternHeuristics = false;
  
      ///
      /// Flags for use by tests
      ///
  
      /// Enable Objective-C Runtime interop code generation and build
      /// configuration options.
      bool EnableObjCInterop = true;
  
      /// On Darwin platforms, use the pre-stable ABI's mark bit for Swift
      /// classes instead of the stable ABI's bit.
      bool UseDarwinPreStableABIBit = !bool(SWIFT_DARWIN_ENABLE_STABLE_ABI_BIT);
  
      /// Enables checking that uses of @objc require importing
      /// the Foundation module.
      /// This is enabled by default because SILGen can crash in such a case, but
      /// it gets disabled when compiling the Swift core stdlib.
      bool EnableObjCAttrRequiresFoundation = true;
  
      /// If true, <code>@testable import Foo</code> produces an error if \c Foo
      /// was not compiled with -enable-testing.
      bool EnableTestableAttrRequiresTestableModule = true;
  
      ///
      /// Flags for developers
      ///
  
      /// \brief Whether we are debugging the constraint solver.
      ///
      /// This option enables verbose debugging output from the constraint
      /// solver.
      bool DebugConstraintSolver = false;
  
      /// \brief Specific solution attempt for which the constraint
      /// solver should be debugged.
      unsigned DebugConstraintSolverAttempt = 0;
  
      /// \brief Enable named lazy member loading.
      bool NamedLazyMemberLoading = true;
  
      /// Debug the generic signatures computed by the generic signature builder.
      bool DebugGenericSignatures = false;
  
      /// Triggers llvm fatal_error if typechecker tries to typecheck a decl or an
      /// identifier reference with the provided prefix name.
      /// This is for testing purposes.
      std::string DebugForbidTypecheckPrefix;
  
      /// \brief How to diagnose cycles encountered
      CycleDiagnosticKind EvaluatorCycleDiagnostics =
          CycleDiagnosticKind::NoDiagnose;
  
      /// \brief The path to which we should emit GraphViz output for the complete
      /// request-evaluator graph.
      std::string RequestEvaluatorGraphVizPath;
  
      /// \brief The upper bound, in bytes, of temporary data that can be
      /// allocated by the constraint solver.
      unsigned SolverMemoryThreshold = 512 * 1024 * 1024;
  
      unsigned SolverBindingThreshold = 1024 * 1024;
  
      /// \brief The upper bound to number of sub-expressions unsolved
      /// before termination of the shrink phrase of the constraint solver.
      unsigned SolverShrinkUnsolvedThreshold = 10;
  
      /// Disable the shrink phase of the expression type checker.
      bool SolverDisableShrink = false;
  
      /// Disable constraint system performance hacks.
      bool DisableConstraintSolverPerformanceHacks = false;
  
      /// \brief Enable experimental operator designated types feature.
      bool EnableOperatorDesignatedTypes = false;
  
      /// \brief Enable constraint solver support for experimental
      ///        operator protocol designator feature.
      bool SolverEnableOperatorDesignatedTypes = false;
  
      /// The maximum depth to which to test decl circularity.
      unsigned MaxCircularityDepth = 500;
  
      /// \brief Perform all dynamic allocations using malloc/free instead of
      /// optimized custom allocator, so that memory debugging tools can be used.
      bool UseMalloc = false;
  
      /// \brief Enable experimental property behavior feature.
      bool EnableExperimentalPropertyBehaviors = false;
  
      /// \brief Staging flag for treating inout parameters as Thread Sanitizer
      /// accesses.
      bool DisableTsanInoutInstrumentation = false;
  
      /// Should we check the target OSs of serialized modules to see that they're
      /// new enough?
      bool EnableTargetOSChecking = true;
  
      /// Whether to attempt to recover from missing cross-references and other
      /// errors when deserializing from a Swift module.
      ///
      /// This is a staging flag; eventually it will be removed.
      bool EnableDeserializationRecovery = true;
  
      /// Should we use \c ASTScope-based resolution for unqualified name lookup?
      bool EnableASTScopeLookup = false;
  
      /// Whether to use the import as member inference system
      ///
      /// When importing a global, try to infer whether we can import it as a
      /// member of some type instead. This includes inits, computed properties,
      /// and methods.
      bool InferImportAsMember = false;
  
      /// If set to true, compile with the SIL Opaque Values enabled.
      /// This is for bootstrapping. It can't be in SILOptions because the
      /// TypeChecker uses it to set resolve the ParameterConvention.
      bool EnableSILOpaqueValues = false;
      
      /// Enables key path resilience.
      bool EnableKeyPathResilience = true;
  
      /// If set to true, the diagnosis engine can assume the emitted diagnostics
      /// will be used in editor. This usually leads to more aggressive fixit.
      bool DiagnosticsEditorMode = false;
  
      /// Whether to enable Swift 3 @objc inference, e.g., for members of
      /// Objective-C-derived classes and 'dynamic' members.
      bool EnableSwift3ObjCInference = false;
  
      /// Warn about cases where Swift 3 would infer @objc but later versions
      /// of Swift do not.
      Swift3ObjCInferenceWarnings WarnSwift3ObjCInference =
        Swift3ObjCInferenceWarnings::None;
  
      /// Diagnose implicit 'override'.
      bool WarnImplicitOverrides = false;
  
      /// Diagnose uses of NSCoding with classes that have unstable mangled names.
      bool EnableNSKeyedArchiverDiagnostics = true;
  
      /// Diagnose switches over non-frozen enums that do not have catch-all
      /// cases.
      bool EnableNonFrozenEnumExhaustivityDiagnostics = false;
  
      /// Regex for the passes that should report passed and missed optimizations.
      ///
      /// These are shared_ptrs so that this class remains copyable.
      std::shared_ptr<llvm::Regex> OptimizationRemarkPassedPattern;
      std::shared_ptr<llvm::Regex> OptimizationRemarkMissedPattern;
  
      /// When a conversion from String to Substring fails, emit a fix-it to append
      /// the void subscript '[]'.
      /// FIXME: Remove this flag when void subscripts are implemented.
      /// This is used to guard preemptive testing for the fix-it.
      bool FixStringToSubstringConversions = false;
  
      /// Whether collect tokens during parsing for syntax coloring.
      bool CollectParsedToken = false;
  
      /// Whether to parse syntax tree. If the syntax tree is built, the generated
      /// AST may not be correct when syntax nodes are reused as part of
      /// incrementals parsing.
      bool BuildSyntaxTree = false;
  
      /// Whether to verify the parsed syntax tree and emit related diagnostics.
      bool VerifySyntaxTree = false;
  
      /// Sets the target we are building for and updates platform conditions
      /// to match.
      ///
      /// \returns A pair - the first element is true if the OS was invalid.
      /// The second element is true if the Arch was invalid.
      std::pair<bool, bool> setTarget(llvm::Triple triple);
  
      /// Returns the minimum platform version to which code will be deployed.
      ///
      /// This is only implemented on certain OSs. If no target has been
      /// configured, returns v0.0.0.
      llvm::VersionTuple getMinPlatformVersion() const {
        unsigned major, minor, revision;
        if (Target.isMacOSX()) {
          Target.getMacOSXVersion(major, minor, revision);
        } else if (Target.isiOS()) {
          Target.getiOSVersion(major, minor, revision);
        } else if (Target.isWatchOS()) {
          Target.getOSVersion(major, minor, revision);
        } else if (Target.isOSLinux() || Target.isOSFreeBSD() ||
                   Target.isAndroid() || Target.isOSWindows() ||
                   Target.isPS4() || Target.isOSHaiku() ||
                   Target.getTriple().empty()) {
          major = minor = revision = 0;
        } else {
          llvm_unreachable("Unsupported target OS");
        }
        return llvm::VersionTuple(major, minor, revision);
      }
  
      /// Sets an implicit platform condition.
      void addPlatformConditionValue(PlatformConditionKind Kind, StringRef Value) {
        assert(!Value.empty());
        PlatformConditionValues.emplace_back(Kind, Value);
      }
  
      /// Removes all values added with addPlatformConditionValue.
      void clearAllPlatformConditionValues() {
        PlatformConditionValues.clear();
      }
      
      /// Returns the value for the given platform condition or an empty string.
      StringRef getPlatformConditionValue(PlatformConditionKind Kind) const;
  
      /// Check whether the given platform condition matches the given value.
      bool checkPlatformCondition(PlatformConditionKind Kind, StringRef Value) const;
  
      /// Explicit conditional compilation flags, initialized via the '-D'
      /// compiler flag.
      void addCustomConditionalCompilationFlag(StringRef Name) {
        assert(!Name.empty());
        CustomConditionalCompilationFlags.push_back(Name);
      }
  
      /// Determines if a given conditional compilation flag has been set.
      bool isCustomConditionalCompilationFlagSet(StringRef Name) const;
  
      ArrayRef<std::pair<PlatformConditionKind, std::string>>
      getPlatformConditionValues() const {
        return PlatformConditionValues;
      }
  
      ArrayRef<std::string> getCustomConditionalCompilationFlags() const {
        return CustomConditionalCompilationFlags;
      }
  
      /// Whether our effective Swift version is in the Swift 3 family
      bool isSwiftVersion3() const {
        return EffectiveLanguageVersion.isVersion3();
      }
  
      /// Whether our effective Swift version is at least 'major'.
      ///
      /// This is usually the check you want; for example, when introducing
      /// a new language feature which is only visible in Swift 5, you would
      /// check for isSwiftVersionAtLeast(5).
      bool isSwiftVersionAtLeast(unsigned major, unsigned minor = 0) const {
        return EffectiveLanguageVersion.isVersionAtLeast(major, minor);
      }
  
      /// Returns true if the given platform condition argument represents
      /// a supported target operating system.
      ///
      /// \param suggestions Populated with suggested replacements
      /// if a match is not found.
      static bool checkPlatformConditionSupported(
        PlatformConditionKind Kind, StringRef Value,
        std::vector<StringRef> &suggestions);
  
      /// Return a hash code of any components from these options that should
      /// contribute to a Swift Bridging PCH hash.
      llvm::hash_code getPCHHashComponents() const {
        auto code = llvm::hash_value(Target.str());
        SmallString<16> Scratch;
        llvm::raw_svector_ostream OS(Scratch);
        OS << EffectiveLanguageVersion;
        code = llvm::hash_combine(code, OS.str());
        return code;
      }
  
    private:
      llvm::SmallVector<std::pair<PlatformConditionKind, std::string>, 5>
          PlatformConditionValues;
      llvm::SmallVector<std::string, 2> CustomConditionalCompilationFlags;
    };
  } // end namespace swift
  
  #endif // SWIFT_BASIC_LANGOPTIONS_H
  