Introduce Name Binding as a Frontend Action

Introduces the -name-bind frontend action that is intended as an intermediary between the parse-only actions and a full typechecking pass.  In this phase, module imports will be validated and resolved, making it possible to emit full make-style dependencies files among other things.

Note that all information available to a parse-only pass is available to name binding, but because it does not continue-on to typecheck input files, full semantic information is not.

Author: CodaFi

include/swift/Frontend/Frontend.h

@@ -539,10 +539,14 @@ class CompilerInstance {
 
   /// Parses the input file but does no type-checking or module imports.
   /// Note that this only supports parsing an invocation with a single file.
-  ///
-  ///
   void performParseOnly(bool EvaluateConditionals = false);
 
+  /// Parses and performs name binding on all input files.
+  ///
+  /// Like a parse-only invocation, a single file is required. Unlike a
+  /// parse-only invocation, module imports will be processed.
+  void performParseAndNameBindingOnly();
+
 private:
   SourceFile *
   createSourceFileForMainModule(SourceFileKind FileKind,
@@ -581,7 +585,9 @@ class CompilerInstance {
 
   void addMainFileToModule(const ImplicitImports &implicitImports);
 
-  void parseAndCheckTypes(const ImplicitImports &implicitImports);
+  void performSemaUpTo(SourceFile::ASTStage_t LimitStage);
+  void parseAndCheckTypesUpTo(const ImplicitImports &implicitImports,
+                              SourceFile::ASTStage_t LimitStage);
 
   void parseLibraryFile(unsigned BufferID,
                         const ImplicitImports &implicitImports,
@@ -600,9 +606,10 @@ class CompilerInstance {
 
   void forEachFileToTypeCheck(llvm::function_ref<void(SourceFile &)> fn);
 
-  void parseAndTypeCheckMainFile(PersistentParserState &PersistentState,
-                                 DelayedParsingCallbacks *DelayedParseCB,
-                                 OptionSet<TypeCheckingFlags> TypeCheckOptions);
+  void parseAndTypeCheckMainFileUpTo(SourceFile::ASTStage_t LimitStage,
+                                     PersistentParserState &PersistentState,
+                                     DelayedParsingCallbacks *DelayedParseCB,
+                                     OptionSet<TypeCheckingFlags> TypeCheckOptions);
 
   void finishTypeChecking(OptionSet<TypeCheckingFlags> TypeCheckOptions);
 

include/swift/Frontend/FrontendOptions.h

@@ -105,6 +105,7 @@ class FrontendOptions {
   enum class ActionType {
     NoneAction,        ///< No specific action
     Parse,             ///< Parse only
+    NameBind,          ///< Parse and perform name-binding only
     Typecheck,         ///< Parse and type-check only
     DumpParse,         ///< Parse only and dump AST
     DumpInterfaceHash, ///< Parse and dump the interface token hash.

include/swift/Option/Options.td

@@ -637,6 +637,9 @@ def fixit_all : Flag<["-"], "fixit-all">,
 def parse: Flag<["-"], "parse">,
   HelpText<"Parse input file(s)">, ModeOpt,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
+def namebind : Flag<["-"], "name-bind">,
+  HelpText<"Parse and perform name binding on input file(s)">, ModeOpt,
+  Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;
 def typecheck : Flag<["-"], "typecheck">,
   HelpText<"Parse and type-check input file(s)">, ModeOpt,
   Flags<[FrontendOption, NoInteractiveOption, DoesNotAffectIncrementalBuild]>;

lib/Driver/Driver.cpp

@@ -1370,6 +1370,7 @@ void Driver::buildOutputInfo(const ToolChain &TC, const DerivedArgList &Args,
       OI.LinkAction = LinkKind::None;
       break;
     case options::OPT_parse:
+    case options::OPT_namebind:
     case options::OPT_typecheck:
     case options::OPT_dump_parse:
     case options::OPT_dump_ast:

lib/Frontend/Frontend.cpp

@@ -425,7 +425,21 @@ shouldImplicityImportSwiftOnoneSupportModule(CompilerInvocation &Invocation) {
   return Invocation.getFrontendOptions().isCreatingSIL();
 }
 
+void CompilerInstance::performParseAndNameBindingOnly() {
+  performSemaUpTo(SourceFile::NameBound);
+}
+
 void CompilerInstance::performSema() {
+  performSemaUpTo(SourceFile::TypeChecked);
+}
+
+void CompilerInstance::performSemaUpTo(SourceFile::ASTStage_t LimitStage) {
+  // FIXME: A lot of the logic in `performParseOnly` is a stripped-down version
+  // of the logic in `performSemaUpTo`.  We should try to unify them over time.
+  if (LimitStage <= SourceFile::Parsed) {
+    return performParseOnly();
+  }
+
   FrontendStatsTracer tracer(Context->Stats, "perform-sema");
   Context->LoadedModules[MainModule->getName()] = getMainModule();
 
@@ -457,9 +471,10 @@ void CompilerInstance::performSema() {
   if (MainBufferID != NO_SUCH_BUFFER)
     addMainFileToModule(implicitImports);
 
-  parseAndCheckTypes(implicitImports);
+  parseAndCheckTypesUpTo(implicitImports, LimitStage);
 }
 
+
 CompilerInstance::ImplicitImports::ImplicitImports(CompilerInstance &compiler) {
   kind = compiler.Invocation.getImplicitModuleImportKind();
 
@@ -575,8 +590,8 @@ void CompilerInstance::addMainFileToModule(
   addAdditionalInitialImportsTo(MainFile, implicitImports);
 }
 
-void CompilerInstance::parseAndCheckTypes(
-    const ImplicitImports &implicitImports) {
+void CompilerInstance::parseAndCheckTypesUpTo(
+    const ImplicitImports &implicitImports, SourceFile::ASTStage_t limitStage) {
   FrontendStatsTracer tracer(Context->Stats, "parse-and-check-types");
   // Delayed parsing callback for the primary file, or all files
   // in non-WMO mode.
@@ -611,8 +626,8 @@ void CompilerInstance::parseAndCheckTypes(
   // In addition, the main file has parsing and type-checking
   // interwined.
   if (MainBufferID != NO_SUCH_BUFFER) {
-    parseAndTypeCheckMainFile(PersistentState, PrimaryDelayedCB.get(),
-                              TypeCheckOptions);
+    parseAndTypeCheckMainFileUpTo(limitStage, PersistentState,
+                                  PrimaryDelayedCB.get(), TypeCheckOptions);
   }
 
   assert(llvm::all_of(MainModule->getFiles(), [](const FileUnit *File) -> bool {
@@ -623,6 +638,11 @@ void CompilerInstance::parseAndCheckTypes(
   }) && "some files have not yet had their imports resolved");
   MainModule->setHasResolvedImports();
 
+  // If the limiting AST stage is name binding, we're done.
+  if (limitStage <= SourceFile::NameBound) {
+    return;
+  }
+
   const auto &options = Invocation.getFrontendOptions();
   forEachFileToTypeCheck([&](SourceFile &SF) {
     performTypeChecking(SF, PersistentState.getTopLevelContext(),
@@ -720,7 +740,8 @@ bool CompilerInstance::parsePartialModulesAndLibraryFiles(
   return hadLoadError;
 }
 
-void CompilerInstance::parseAndTypeCheckMainFile(
+void CompilerInstance::parseAndTypeCheckMainFileUpTo(
+    SourceFile::ASTStage_t LimitStage,
     PersistentParserState &PersistentState,
     DelayedParsingCallbacks *DelayedParseCB,
     OptionSet<TypeCheckingFlags> TypeCheckOptions) {
@@ -747,15 +768,27 @@ void CompilerInstance::parseAndTypeCheckMainFile(
     parseIntoSourceFile(MainFile, MainFile.getBufferID().getValue(), &Done,
                         TheSILModule ? &SILContext : nullptr, &PersistentState,
                         DelayedParseCB);
+
     if (mainIsPrimary) {
-      const auto &options = Invocation.getFrontendOptions();
-      performTypeChecking(MainFile, PersistentState.getTopLevelContext(),
-                          TypeCheckOptions, CurTUElem,
-                          options.WarnLongFunctionBodies,
-                          options.WarnLongExpressionTypeChecking,
-                          options.SolverExpressionTimeThreshold,
-                          options.SwitchCheckingInvocationThreshold);
+      switch (LimitStage) {
+      case SourceFile::Parsing:
+      case SourceFile::Parsed:
+        llvm_unreachable("invalid limit stage");
+      case SourceFile::NameBound:
+        performNameBinding(MainFile, CurTUElem);
+        break;
+      case SourceFile::TypeChecked:
+        const auto &options = Invocation.getFrontendOptions();
+        performTypeChecking(MainFile, PersistentState.getTopLevelContext(),
+                            TypeCheckOptions, CurTUElem,
+                            options.WarnLongFunctionBodies,
+                            options.WarnLongExpressionTypeChecking,
+                            options.SolverExpressionTimeThreshold,
+                            options.SwitchCheckingInvocationThreshold);
+        break;
+      }
     }
+
     CurTUElem = MainFile.Decls.size();
   } while (!Done);
 

lib/Frontend/FrontendOptions.cpp

@@ -31,6 +31,7 @@ bool FrontendOptions::needsProperModuleName(ActionType action) {
   switch (action) {
   case ActionType::NoneAction:
   case ActionType::Parse:
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::DumpParse:
   case ActionType::DumpAST:
@@ -65,6 +66,7 @@ bool FrontendOptions::isActionImmediate(ActionType action) {
   switch (action) {
   case ActionType::NoneAction:
   case ActionType::Parse:
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::DumpParse:
   case ActionType::DumpAST:
@@ -134,6 +136,7 @@ FrontendOptions::suffixForPrincipalOutputFileForAction(ActionType action) {
     return StringRef();
 
   case ActionType::Parse:
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::DumpParse:
   case ActionType::DumpInterfaceHash:
@@ -195,6 +198,7 @@ bool FrontendOptions::canActionEmitDependencies(ActionType action) {
   case ActionType::Immediate:
   case ActionType::REPL:
     return false;
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::MergeModules:
   case ActionType::EmitModuleOnly:
@@ -216,6 +220,7 @@ bool FrontendOptions::canActionEmitReferenceDependencies(ActionType action) {
   switch (action) {
   case ActionType::NoneAction:
   case ActionType::Parse:
+  case ActionType::NameBind:
   case ActionType::DumpParse:
   case ActionType::DumpInterfaceHash:
   case ActionType::DumpAST:
@@ -258,6 +263,7 @@ bool FrontendOptions::canActionEmitObjCHeader(ActionType action) {
   case ActionType::REPL:
     return false;
   case ActionType::Parse:
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::MergeModules:
   case ActionType::EmitModuleOnly:
@@ -288,6 +294,7 @@ bool FrontendOptions::canActionEmitLoadedModuleTrace(ActionType action) {
   case ActionType::Immediate:
   case ActionType::REPL:
     return false;
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::MergeModules:
   case ActionType::EmitModuleOnly:
@@ -309,6 +316,7 @@ bool FrontendOptions::canActionEmitModule(ActionType action) {
   switch (action) {
   case ActionType::NoneAction:
   case ActionType::Parse:
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::DumpParse:
   case ActionType::DumpInterfaceHash:
@@ -343,6 +351,7 @@ bool FrontendOptions::canActionEmitModuleDoc(ActionType action) {
 bool FrontendOptions::doesActionProduceOutput(ActionType action) {
   switch (action) {
   case ActionType::Parse:
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::DumpParse:
   case ActionType::DumpAST:
@@ -388,6 +397,7 @@ bool FrontendOptions::doesActionProduceTextualOutput(ActionType action) {
     return false;
 
   case ActionType::Parse:
+  case ActionType::NameBind:
   case ActionType::Typecheck:
   case ActionType::DumpParse:
   case ActionType::DumpInterfaceHash:

lib/FrontendTool/FrontendTool.cpp

@@ -895,11 +895,14 @@ static bool performCompile(CompilerInstance &Instance,
   if (Invocation.getInputKind() == InputFileKind::IFK_LLVM_IR)
     return compileLLVMIR(Invocation, Instance, Stats);
 
-  if (FrontendOptions::shouldActionOnlyParse(Action))
+  if (FrontendOptions::shouldActionOnlyParse(Action)) {
     Instance.performParseOnly(/*EvaluateConditionals*/
                     Action == FrontendOptions::ActionType::EmitImportedModules);
-  else
+  } else if (Action == FrontendOptions::ActionType::NameBind) {
+    Instance.performParseAndNameBindingOnly();
+  } else {
     Instance.performSema();
+  }
 
   SWIFT_DEFER {
     // Emit request-evaluator graph via GraphViz, if requested.
@@ -912,8 +915,15 @@ static bool performCompile(CompilerInstance &Instance,
     }
   };
 
+  ASTContext &Context = Instance.getASTContext();
   if (Action == FrontendOptions::ActionType::Parse)
-    return Instance.getASTContext().hadError();
+    return Context.hadError();
+
+  (void)emitMakeDependenciesIfNeeded(Context.Diags,
+                                     Instance.getDependencyTracker(), opts);
+
+  if (Action == FrontendOptions::ActionType::NameBind)
+    return Context.hadError();
 
   if (observer)
     observer->performedSemanticAnalysis(Instance);
@@ -929,8 +939,6 @@ static bool performCompile(CompilerInstance &Instance,
       debugFailWithCrash();
   }
 
-  ASTContext &Context = Instance.getASTContext();
-
   verifyGenericSignaturesIfNeeded(Invocation, Context);
 
   (void)migrator::updateCodeAndEmitRemapIfNeeded(&Instance, Invocation);
@@ -948,9 +956,6 @@ static bool performCompile(CompilerInstance &Instance,
   if (opts.PrintClangStats && Context.getClangModuleLoader())
     Context.getClangModuleLoader()->printStatistics();
 
-  (void)emitMakeDependenciesIfNeeded(Context.Diags,
-                                     Instance.getDependencyTracker(), opts);
-
   emitReferenceDependenciesForAllPrimaryInputsIfNeeded(Invocation, Instance);
 
   (void)emitLoadedModuleTraceForAllPrimariesIfNeeded(

test/Frontend/dependencies.swift

@@ -2,7 +2,7 @@
 
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend -emit-dependencies-path - -typecheck %S/../Inputs/empty\ file.swift | %FileCheck -check-prefix=CHECK-BASIC %s
+// RUN: %target-swift-frontend -emit-dependencies-path - -name-bind %S/../Inputs/empty\ file.swift | %FileCheck -check-prefix=CHECK-BASIC %s
 // RUN: %target-swift-frontend -emit-reference-dependencies-path - -typecheck -primary-file %S/../Inputs/empty\ file.swift | %FileCheck -check-prefix=CHECK-BASIC-YAML %s
 
 // RUN: %target-swift-frontend -emit-dependencies-path %t.d -emit-reference-dependencies-path %t.swiftdeps -typecheck -primary-file %S/../Inputs/empty\ file.swift
@@ -38,7 +38,7 @@
 // CHECK-MULTIPLE-OUTPUTS: Swift.swiftmodule
 // CHECK-MULTIPLE-OUTPUTS-NOT: :
 
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -import-objc-header %S/Inputs/dependencies/extra-header.h -emit-dependencies-path - -typecheck %s | %FileCheck -check-prefix=CHECK-IMPORT %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -import-objc-header %S/Inputs/dependencies/extra-header.h -emit-dependencies-path - -name-bind %s | %FileCheck -check-prefix=CHECK-IMPORT %s
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -import-objc-header %S/Inputs/dependencies/extra-header.h -emit-reference-dependencies-path - -typecheck -primary-file %s | %FileCheck -check-prefix=CHECK-IMPORT-YAML %s
 
 // CHECK-IMPORT-LABEL: - :