Move the defined functions list onto SourceFile

Author: CodaFi

include/swift/AST/SourceFile.h

@@ -267,6 +267,14 @@ class SourceFile final : public FileUnit {
   /// A set of synthesized declarations that need to be type checked.
   llvm::SmallVector<Decl *, 8> SynthesizedDecls;
 
+  /// The list of functions defined in this file whose bodies have yet to be
+  /// typechecked. They must be held in this list instead of eagerly validated
+  /// because their bodies may force us to perform semantic checks of arbitrary
+  /// complexity, and we currently cannot handle those checks in isolation. E.g.
+  /// we cannot, in general, perform witness matching on singular requirements
+  /// unless the entire conformance has been evaluated.
+  std::vector<AbstractFunctionDecl *> DelayedFunctions;
+
   /// We might perform type checking on the same source file more than once,
   /// if its the main file or a REPL instance, so keep track of the last
   /// checked synthesized declaration to avoid duplicating work.

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -1166,10 +1166,15 @@ namespace {
 class DeclChecker : public DeclVisitor<DeclChecker> {
 public:
   ASTContext &Ctx;
+  SourceFile *SF;
 
-  explicit DeclChecker(ASTContext &ctx) : Ctx(ctx) {}
+  explicit DeclChecker(ASTContext &ctx, SourceFile *SF) : Ctx(ctx), SF(SF) {}
 
   ASTContext &getASTContext() const { return Ctx; }
+  void addDelayedFunction(AbstractFunctionDecl *AFD) {
+    if (!SF) return;
+    SF->DelayedFunctions.push_back(AFD);
+  }
 
   void visit(Decl *decl) {
     if (auto *Stats = getASTContext().Stats)
@@ -1385,7 +1390,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     TypeChecker::checkDeclAttributes(PBD);
 
     bool isInSILMode = false;
-    if (auto sourceFile = DC->getParentSourceFile())
+    if (auto sourceFile = SF)
       isInSILMode = sourceFile->Kind == SourceFileKind::SIL;
     bool isTypeContext = DC->isTypeContext();
 
@@ -1443,7 +1448,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
         // protocol.
         if (var->isStatic() && !isa<ProtocolDecl>(DC)) {
           // ...but don't enforce this for SIL or module interface files.
-          switch (DC->getParentSourceFile()->Kind) {
+          switch (SF->Kind) {
           case SourceFileKind::Interface:
           case SourceFileKind::SIL:
             return;
@@ -1461,7 +1466,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
         // Global variables require an initializer in normal source files.
         if (DC->isModuleScopeContext()) {
-          switch (DC->getParentSourceFile()->Kind) {
+          switch (SF->Kind) {
           case SourceFileKind::Main:
           case SourceFileKind::REPL:
           case SourceFileKind::Interface:
@@ -1994,7 +1999,6 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     // Check for circular inheritance within the protocol.
     (void)PD->hasCircularInheritedProtocols();
 
-    auto *SF = PD->getParentSourceFile();
     if (SF) {
       if (auto *tracker = SF->getReferencedNameTracker()) {
         bool isNonPrivate = (PD->getFormalAccess() > AccessLevel::FilePrivate);
@@ -2150,9 +2154,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     } else if (shouldSkipBodyTypechecking(FD)) {
       FD->setBodySkipped(FD->getBodySourceRange());
     } else {
-      // FIXME: Remove TypeChecker dependency.
-      auto &TC = *Ctx.getLegacyGlobalTypeChecker();
-      TC.definedFunctions.push_back(FD);
+      addDelayedFunction(FD);
     }
 
     checkExplicitAvailability(FD);
@@ -2484,9 +2486,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     } else if (shouldSkipBodyTypechecking(CD)) {
       CD->setBodySkipped(CD->getBodySourceRange());
     } else {
-      // FIXME: Remove TypeChecker dependency.
-      auto &TC = *Ctx.getLegacyGlobalTypeChecker();
-      TC.definedFunctions.push_back(CD);
+      addDelayedFunction(CD);
     }
 
     checkDefaultArguments(CD->getParameters());
@@ -2501,14 +2501,13 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
     } else if (shouldSkipBodyTypechecking(DD)) {
       DD->setBodySkipped(DD->getBodySourceRange());
     } else {
-      // FIXME: Remove TypeChecker dependency.
-      auto &TC = *Ctx.getLegacyGlobalTypeChecker();
-      TC.definedFunctions.push_back(DD);
+      addDelayedFunction(DD);
     }
   }
 };
 } // end anonymous namespace
 
 void TypeChecker::typeCheckDecl(Decl *D) {
-  DeclChecker(D->getASTContext()).visit(D);
+  auto *SF = D->getDeclContext()->getParentSourceFile();
+  DeclChecker(D->getASTContext(), SF).visit(D);
 }

lib/Sema/TypeChecker.cpp

@@ -289,16 +289,16 @@ static void bindExtensions(SourceFile &SF) {
   // typeCheckDecl().
 }
 
-static void typeCheckFunctionsAndExternalDecls(SourceFile &SF, TypeChecker &TC) {
+static void typeCheckDelayedFunctions(SourceFile &SF) {
   unsigned currentFunctionIdx = 0;
   unsigned currentSynthesizedDecl = SF.LastCheckedSynthesizedDecl;
   do {
     // Type check the body of each of the function in turn.  Note that outside
     // functions must be visited before nested functions for type-checking to
     // work correctly.
-    for (unsigned n = TC.definedFunctions.size(); currentFunctionIdx != n;
+    for (unsigned n = SF.DelayedFunctions.size(); currentFunctionIdx != n;
          ++currentFunctionIdx) {
-      auto *AFD = TC.definedFunctions[currentFunctionIdx];
+      auto *AFD = SF.DelayedFunctions[currentFunctionIdx];
       assert(!AFD->getDeclContext()->isLocalContext());
 
       TypeChecker::typeCheckAbstractFunctionBody(AFD);
@@ -312,15 +312,15 @@ static void typeCheckFunctionsAndExternalDecls(SourceFile &SF, TypeChecker &TC)
       TypeChecker::typeCheckDecl(decl);
     }
 
-  } while (currentFunctionIdx < TC.definedFunctions.size() ||
+  } while (currentFunctionIdx < SF.DelayedFunctions.size() ||
            currentSynthesizedDecl < SF.SynthesizedDecls.size());
 
 
-  for (AbstractFunctionDecl *FD : llvm::reverse(TC.definedFunctions)) {
+  for (AbstractFunctionDecl *FD : llvm::reverse(SF.DelayedFunctions)) {
     TypeChecker::computeCaptures(FD);
   }
 
-  TC.definedFunctions.clear();
+  SF.DelayedFunctions.clear();
 }
 
 void swift::performTypeChecking(SourceFile &SF) {
@@ -392,7 +392,7 @@ TypeCheckSourceFileRequest::evaluate(Evaluator &eval, SourceFile *SF) const {
     if (SF->Kind == SourceFileKind::REPL && !Ctx.hadError())
       TypeChecker::processREPLTopLevel(*SF);
 
-    typeCheckFunctionsAndExternalDecls(*SF, TC);
+    typeCheckDelayedFunctions(*SF);
   }
 
   // Checking that benefits from having the whole module available.

lib/Sema/TypeChecker.h

@@ -405,10 +405,6 @@ enum class CheckedCastContextKind {
 /// The Swift type checker, which takes a parsed AST and performs name binding,
 /// type checking, and semantic analysis to produce a type-annotated AST.
 class TypeChecker final {
-public:
-  /// The list of function definitions we've encountered.
-  std::vector<AbstractFunctionDecl *> definedFunctions;
-
 private:
   TypeChecker() = default;
   ~TypeChecker() = default;