Merge pull request #9413 from rintaro/ast-eliminate-ifconfigstmt

[AST] Eliminate IfConfigStmt

Author: slavapestov

include/swift/AST/Decl.h

@@ -44,6 +44,7 @@ namespace swift {
   class GenericEnvironment;
   class ArchetypeType;
   class ASTContext;
+  struct ASTNode;
   class ASTPrinter;
   class ASTWalker;
   class ConstructorDecl;
@@ -2027,34 +2028,33 @@ class SerializedTopLevelCodeDeclContext : public SerializedLocalDeclContext {
   }
 };
 
-/// IfConfigDecl - This class represents the declaration-side representation of
-/// #if/#else/#endif blocks. Active and inactive block members are stored
-/// separately, with the intention being that active members will be handed
-/// back to the enclosing declaration.
+/// IfConfigDecl - This class represents #if/#else/#endif blocks.
+/// Active and inactive block members are stored separately, with the intention
+/// being that active members will be handed back to the enclosing context.
 class IfConfigDecl : public Decl {
   /// An array of clauses controlling each of the #if/#elseif/#else conditions.
   /// The array is ASTContext allocated.
-  ArrayRef<IfConfigClause<Decl *>> Clauses;
+  ArrayRef<IfConfigClause> Clauses;
   SourceLoc EndLoc;
 public:
 
-  IfConfigDecl(DeclContext *Parent, ArrayRef<IfConfigClause<Decl *>> Clauses,
+  IfConfigDecl(DeclContext *Parent, ArrayRef<IfConfigClause> Clauses,
                SourceLoc EndLoc, bool HadMissingEnd)
     : Decl(DeclKind::IfConfig, Parent), Clauses(Clauses), EndLoc(EndLoc)
   {
     IfConfigDeclBits.HadMissingEnd = HadMissingEnd;
   }
 
-  ArrayRef<IfConfigClause<Decl *>> getClauses() const { return Clauses; }
+  ArrayRef<IfConfigClause> getClauses() const { return Clauses; }
 
   /// Return the active clause, or null if there is no active one.
-  const IfConfigClause<Decl *> *getActiveClause() const {
+  const IfConfigClause *getActiveClause() const {
     for (auto &Clause : Clauses)
       if (Clause.isActive) return &Clause;
     return nullptr;
   }
 
-  const ArrayRef<Decl*> getActiveMembers() const {
+  const ArrayRef<ASTNode> getActiveClauseElements() const {
     if (auto *Clause = getActiveClause())
       return Clause->Elements;
     return {};

include/swift/AST/IfConfigClause.h

@@ -22,11 +22,11 @@
 namespace swift {
   class Expr;
   class SourceLoc;
+  struct ASTNode;
 
 /// This represents one part of a #if block.  If the condition field is
 /// non-null, then this represents a #if or a #elseif, otherwise it represents
 /// an #else block.
-template <typename ElemTy>
 struct IfConfigClause {
   /// The location of the #if, #elseif, or #else keyword.
   SourceLoc Loc;
@@ -36,13 +36,13 @@ struct IfConfigClause {
   Expr *Cond;
 
   /// Elements inside the clause
-  ArrayRef<ElemTy> Elements;
+  ArrayRef<ASTNode> Elements;
 
   /// True if this is the active clause of the #if block.
   bool isActive;
 
-  IfConfigClause<ElemTy>(SourceLoc Loc, Expr *Cond,
-                         ArrayRef<ElemTy> Elements, bool isActive)
+  IfConfigClause(SourceLoc Loc, Expr *Cond,
+                 ArrayRef<ASTNode> Elements, bool isActive)
     : Loc(Loc), Cond(Cond), Elements(Elements), isActive(isActive) {
   }
 };

include/swift/AST/PrintOptions.h

@@ -279,7 +279,7 @@ struct PrintOptions {
   /// Print all decls that have at least this level of access.
   Accessibility AccessibilityFilter = Accessibility::Private;
 
-  /// Print IfConfigDecls and IfConfigStmts.
+  /// Print IfConfigDecls.
   bool PrintIfConfig = true;
 
   /// Whether we are printing for sil.

include/swift/AST/Stmt.h

@@ -655,46 +655,6 @@ class GuardStmt : public LabeledConditionalStmt {
   static bool classof(const Stmt *S) { return S->getKind() == StmtKind::Guard; }
 };
 
-/// IfConfigStmt - This class models the statement-side representation of
-/// #if/#else/#endif blocks.
-class IfConfigStmt : public Stmt {
-  /// An array of clauses controlling each of the #if/#elseif/#else conditions.
-  /// The array is ASTContext allocated.
-  ArrayRef<IfConfigClause<ASTNode>> Clauses;
-  SourceLoc EndLoc;
-  bool HadMissingEnd;
-
-public:
-  IfConfigStmt(ArrayRef<IfConfigClause<ASTNode>> Clauses, SourceLoc EndLoc,
-               bool HadMissingEnd)
-  : Stmt(StmtKind::IfConfig, /*implicit=*/false),
-    Clauses(Clauses), EndLoc(EndLoc), HadMissingEnd(HadMissingEnd) {}
-  
-  SourceLoc getIfLoc() const { return Clauses[0].Loc; }
-
-  SourceLoc getStartLoc() const { return getIfLoc(); }
-  SourceLoc getEndLoc() const { return EndLoc; }
-
-  bool hadMissingEnd() const { return HadMissingEnd; }
-  
-  const ArrayRef<IfConfigClause<ASTNode>> &getClauses() const {
-    return Clauses;
-  }
-
-  ArrayRef<ASTNode> getActiveClauseElements() const {
-    for (auto &Clause : Clauses)
-      if (Clause.isActive)
-        return Clause.Elements;
-    return ArrayRef<ASTNode>();
-  }
-
-  // Implement isa/cast/dyncast/etc.
-  static bool classof(const Stmt *S) {
-    return S->getKind() == StmtKind::IfConfig;
-  }
-};
-
-  
 /// WhileStmt - while statement. After type-checking, the condition is of
 /// type Builtin.Int1.
 class WhileStmt : public LabeledConditionalStmt {

include/swift/AST/StmtNodes.def

@@ -61,7 +61,6 @@ STMT(Catch, Stmt)
 STMT(Break, Stmt)
 STMT(Continue, Stmt)
 STMT(Fallthrough, Stmt)
-STMT(IfConfig, Stmt)
 STMT(Fail, Stmt)
 STMT(Throw, Stmt)
 

include/swift/Parse/Parser.h

@@ -716,7 +716,11 @@ class Parser {
   ParserResult<TypeDecl> parseDeclAssociatedType(ParseDeclOptions Flags,
                                                  DeclAttributes &Attributes);
 
-  ParserResult<IfConfigDecl> parseDeclIfConfig(ParseDeclOptions Flags);
+  /// Parse a #if ... #endif directive.
+  /// Delegate callback function to parse elements in the blocks.
+  ParserResult<IfConfigDecl> parseIfConfig(
+    llvm::function_ref<void(SmallVectorImpl<ASTNode> &, bool)> parseElements);
+
   /// Parse a #line/#sourceLocation directive.
   /// 'isLine = true' indicates parsing #line instead of #sourcelocation
   ParserStatus parseLineDirective(bool isLine = false);
@@ -1277,8 +1281,6 @@ class Parser {
   ParserResult<PoundAvailableInfo> parseStmtConditionPoundAvailable();
   ParserResult<Stmt> parseStmtIf(LabeledStmtInfo LabelInfo);
   ParserResult<Stmt> parseStmtGuard();
-  ParserResult<Stmt> parseStmtIfConfig(BraceItemListKind Kind
-                                        = BraceItemListKind::Brace);
   ParserResult<Stmt> parseStmtWhile(LabeledStmtInfo LabelInfo);
   ParserResult<Stmt> parseStmtRepeat(LabeledStmtInfo LabelInfo);
   ParserResult<Stmt> parseStmtDo(LabeledStmtInfo LabelInfo);

lib/AST/ASTDumper.cpp

@@ -1036,33 +1036,41 @@ namespace {
       }
       PrintWithColorRAII(OS, ParenthesisColor) << ')';
     }
+    
+    void printASTNodes(const ArrayRef<ASTNode> &Elements, StringRef Name) {
+      OS.indent(Indent);
+      PrintWithColorRAII(OS, ParenthesisColor) << "(";
+      PrintWithColorRAII(OS, ASTNodeColor) << Name;
+      for (auto Elt : Elements) {
+        OS << '\n';
+        if (auto *SubExpr = Elt.dyn_cast<Expr*>())
+          printRec(SubExpr);
+        else if (auto *SubStmt = Elt.dyn_cast<Stmt*>())
+          printRec(SubStmt);
+        else
+          printRec(Elt.get<Decl*>());
+      }
+      PrintWithColorRAII(OS, ParenthesisColor) << ')';
+    }
 
     void visitIfConfigDecl(IfConfigDecl *ICD) {
-      OS.indent(Indent);
-      PrintWithColorRAII(OS, ParenthesisColor) << '(';
-      OS << "#if_decl\n";
+      printCommon(ICD, "if_config_decl");
       Indent += 2;
       for (auto &Clause : ICD->getClauses()) {
+        OS << '\n';
+        OS.indent(Indent);
+        PrintWithColorRAII(OS, StmtColor) << (Clause.Cond ? "#if:" : "#else:");
+        if (Clause.isActive)
+          PrintWithColorRAII(OS, DeclModifierColor) << " active";
         if (Clause.Cond) {
-          PrintWithColorRAII(OS, ParenthesisColor) << '(';
-          OS << "#if:";
-          if (Clause.isActive) OS << " active";
           OS << "\n";
           printRec(Clause.Cond);
-        } else {
-          OS << '\n';
-          PrintWithColorRAII(OS, ParenthesisColor) << '(';
-          OS << "#else:";
-          if (Clause.isActive) OS << " active";
-          OS << "\n";
         }
 
-        for (auto D : Clause.Elements) {
-          OS << '\n';
-          printRec(D);
-        }
-
-        PrintWithColorRAII(OS, ParenthesisColor) << ')';
+        OS << '\n';
+        Indent += 2;
+        printASTNodes(Clause.Elements, "elements");
+        Indent -= 2;
       }
 
       Indent -= 2;
@@ -1422,35 +1430,6 @@ class PrintStmt : public StmtVisitor<PrintStmt> {
     PrintWithColorRAII(OS, ParenthesisColor) << ')';
   }
 
-  void visitIfConfigStmt(IfConfigStmt *S) {
-    printCommon(S, "#if_stmt");
-    Indent += 2;
-    for (auto &Clause : S->getClauses()) {
-      OS << '\n';
-      OS.indent(Indent);
-      if (Clause.Cond) {
-        PrintWithColorRAII(OS, ParenthesisColor) << '(';
-        PrintWithColorRAII(OS, StmtColor) << "#if:";
-        if (Clause.isActive)
-          PrintWithColorRAII(OS, DeclModifierColor) << " active";
-        OS << '\n';
-        printRec(Clause.Cond);
-      } else {
-        PrintWithColorRAII(OS, StmtColor) << "#else";
-        if (Clause.isActive)
-          PrintWithColorRAII(OS, DeclModifierColor) << " active";
-      }
-
-      OS << '\n';
-      Indent += 2;
-      printASTNodes(Clause.Elements, "elements");
-      Indent -= 2;
-    }
-
-    Indent -= 2;
-    PrintWithColorRAII(OS, ParenthesisColor) << ')';
-  }
-
   void visitDoStmt(DoStmt *S) {
     printCommon(S, "do_stmt") << '\n';
     printRec(S->getBody());

lib/AST/ASTPrinter.cpp

@@ -2360,7 +2360,21 @@ void PrintAST::visitTopLevelCodeDecl(TopLevelCodeDecl *decl) {
 }
 
 void PrintAST::visitIfConfigDecl(IfConfigDecl *ICD) {
-  // FIXME: Pretty print #if decls
+  if (!Options.PrintIfConfig)
+    return;
+
+  for (auto &Clause : ICD->getClauses()) {
+    if (&Clause == &*ICD->getClauses().begin())
+      Printer << tok::pound_if << " /* condition */"; // FIXME: print condition
+    else if (Clause.Cond)
+      Printer << tok::pound_elseif << " /* condition */"; // FIXME: print condition
+    else
+      Printer << tok::pound_else;
+    printASTNodes(Clause.Elements);
+    Printer.printNewline();
+    indent();
+  }
+  Printer << tok::pound_endif;
 }
 
 void PrintAST::visitTypeAliasDecl(TypeAliasDecl *decl) {
@@ -3267,27 +3281,6 @@ void PrintAST::visitGuardStmt(GuardStmt *stmt) {
   visit(stmt->getBody());
 }
 
-void PrintAST::visitIfConfigStmt(IfConfigStmt *stmt) {
-  if (!Options.PrintIfConfig)
-    return;
-
-  for (auto &Clause : stmt->getClauses()) {
-    if (&Clause == &*stmt->getClauses().begin())
-      Printer << tok::pound_if << " "; // FIXME: print condition
-    else if (Clause.Cond)
-      Printer << tok::pound_elseif << ""; // FIXME: print condition
-    else
-      Printer << tok::pound_else;
-    Printer.printNewline();
-    if (printASTNodes(Clause.Elements)) {
-      Printer.printNewline();
-      indent();
-    }
-  }
-  Printer.printNewline();
-  Printer << tok::pound_endif;
-}
-
 void PrintAST::visitWhileStmt(WhileStmt *stmt) {
   Printer << tok::kw_while << " ";
   // FIXME: print condition

lib/AST/ASTScope.cpp

@@ -188,24 +188,6 @@ static bool hasAccessors(AbstractStorageDecl *asd) {
   llvm_unreachable("Unhandled ContinuationKind in switch.");
 }
 
-/// Determine whether this is a top-level code declaration that isn't just
-/// wrapping an #if.
-static bool isRealTopLevelCodeDecl(Decl *decl) {
-  auto topLevelCode = dyn_cast<TopLevelCodeDecl>(decl);
-  if (!topLevelCode) return false;
-
-  // Drop top-level statements containing just an IfConfigStmt.
-  // FIXME: The modeling of IfConfig is weird.
-  auto braceStmt = topLevelCode->getBody();
-  auto elements = braceStmt->getElements();
-  if (elements.size() == 1 &&
-      elements[0].is<Stmt *>() &&
-      isa<IfConfigStmt>(elements[0].get<Stmt *>()))
-    return false;
-
-  return true;
-}
-
 void ASTScope::expand() const {
   assert(!isExpanded() && "Already expanded the children of this node");
   ASTContext &ctx = getASTContext();
@@ -313,7 +295,7 @@ void ASTScope::expand() const {
 
         // If the declaration is a top-level code declaration, turn the source
         // file into a continuation. We're done.
-        if (isRealTopLevelCodeDecl(decl)) {
+        if (isa<TopLevelCodeDecl>(decl)) {
           addActiveContinuation(this);
           break;
         }
@@ -950,7 +932,6 @@ ASTScope *ASTScope::createIfNeeded(const ASTScope *parent, Decl *decl) {
   }
 
   case DeclKind::TopLevelCode:
-    if (!isRealTopLevelCodeDecl(decl)) return nullptr;
     return new (ctx) ASTScope(parent, cast<TopLevelCodeDecl>(decl));
 
   case DeclKind::Protocol:
@@ -1153,7 +1134,6 @@ ASTScope *ASTScope::createIfNeeded(const ASTScope *parent, Stmt *stmt) {
   case StmtKind::Break:
   case StmtKind::Continue:
   case StmtKind::Fallthrough:
-  case StmtKind::IfConfig:
   case StmtKind::Fail:
   case StmtKind::Throw:
     // Nothing to do for these statements.