[Parse] small cleanup in parseBraceItems()

* Reorder 'if ... else if' branches to simplify conditions.
* use 'append()' instead of `for { push_back() }`

Author: rintaro

lib/Parse/ParseStmt.cpp

@@ -245,7 +245,6 @@ ParserStatus Parser::parseBraceItems(SmallVectorImpl<ASTNode> &Entries,
   }
 
   ParserStatus BraceItemsStatus;
-  SmallVector<Decl*, 8> TmpDecls;
 
   bool PreviousHadSemi = true;
   while ((Kind == BraceItemListKind::TopLevelLibrary ||
@@ -292,57 +291,29 @@ ParserStatus Parser::parseBraceItems(SmallVectorImpl<ASTNode> &Entries,
 
     // Parse the decl, stmt, or expression.
     PreviousHadSemi = false;
-    if (isStartOfDecl()
-        && Tok.isNot(
-            tok::pound_if, tok::pound_sourceLocation, tok::pound_line)) {
-      ParserResult<Decl> DeclResult = 
-          parseDecl(IsTopLevel ? PD_AllowTopLevel : PD_Default,
-                    [&](Decl *D) {TmpDecls.push_back(D);});
-      if (DeclResult.isParseError()) {
-        NeedParseErrorRecovery = true;
-        if (DeclResult.hasCodeCompletion() && IsTopLevel &&
-            isCodeCompletionFirstPass()) {
-          consumeDecl(BeginParserPosition, None, IsTopLevel);
-          return DeclResult;
-        }
-      }
-      Result = DeclResult.getPtrOrNull();
-
-      for (Decl *D : TmpDecls)
-        Entries.push_back(D);
-      TmpDecls.clear();
-    } else if (Tok.is(tok::pound_if)) {
+    if (Tok.is(tok::pound_if)) {
       auto IfConfigResult = parseIfConfig(
         [&](SmallVectorImpl<ASTNode> &Elements, bool IsActive) {
           parseBraceItems(Elements, Kind, IsActive
                             ? BraceItemListKind::ActiveConditionalBlock
                             : BraceItemListKind::InactiveConditionalBlock);
         });
-      
-      if (IfConfigResult.isParseError()) {
-        NeedParseErrorRecovery = true;
-        continue;
-      }
-      
-      Result = IfConfigResult.get();
-      
-      if (!Result) {
-        NeedParseErrorRecovery = true;
-        continue;
-      }
+      if (auto ICD = IfConfigResult.getPtrOrNull()) {
+        Result = ICD;
+        // Add the #if block itself
+        Entries.push_back(ICD);
 
-      // Add the #if block itself
-      Entries.push_back(Result);
-
-      IfConfigDecl *ICD = cast<IfConfigDecl>(Result.get<Decl*>());
-      for (auto &Entry : ICD->getActiveClauseElements()) {
-        if (Entry.is<Decl*>() && isa<IfConfigDecl>(Entry.get<Decl*>()))
-          // Don't hoist nested '#if'.
-          continue;
-        Entries.push_back(Entry);
-        if (Entry.is<Decl*>()) {
-          Entry.get<Decl*>()->setEscapedFromIfConfig(true);
+        for (auto &Entry : ICD->getActiveClauseElements()) {
+          if (Entry.is<Decl *>() && isa<IfConfigDecl>(Entry.get<Decl *>()))
+            // Don't hoist nested '#if'.
+            continue;
+          Entries.push_back(Entry);
+          if (Entry.is<Decl *>())
+            Entry.get<Decl *>()->setEscapedFromIfConfig(true);
         }
+      } else {
+        NeedParseErrorRecovery = true;
+        continue;
       }
     } else if (Tok.is(tok::pound_line)) {
       ParserStatus Status = parseLineDirective(true);
@@ -352,6 +323,21 @@ ParserStatus Parser::parseBraceItems(SmallVectorImpl<ASTNode> &Entries,
       ParserStatus Status = parseLineDirective(false);
       BraceItemsStatus |= Status;
       NeedParseErrorRecovery = Status.isError();
+    } else if (isStartOfDecl()) {
+      SmallVector<Decl*, 8> TmpDecls;
+      ParserResult<Decl> DeclResult = 
+          parseDecl(IsTopLevel ? PD_AllowTopLevel : PD_Default,
+                    [&](Decl *D) {TmpDecls.push_back(D);});
+      if (DeclResult.isParseError()) {
+        NeedParseErrorRecovery = true;
+        if (DeclResult.hasCodeCompletion() && IsTopLevel &&
+            isCodeCompletionFirstPass()) {
+          consumeDecl(BeginParserPosition, None, IsTopLevel);
+          return DeclResult;
+        }
+      }
+      Result = DeclResult.getPtrOrNull();
+      Entries.append(TmpDecls.begin(), TmpDecls.end());
     } else if (IsTopLevel) {
       // If this is a statement or expression at the top level of the module,
       // Parse it as a child of a TopLevelCodeDecl.