[clang-diff] Don't ignore nodes from other files

lib/Tooling/ASTDiff/ASTDiff.cpp

 }
 
 template <class T> static bool isNodeExcluded(ASTUnit &AST, T *N) {
   const SourceManager &SM = AST.getSourceManager();
   if (!N)
     return true;
   SourceLocation SLoc = N->getSourceRange().getBegin();
   if (SLoc.isValid()) {
-    // Ignore everything from other files.
-    if (!SM.isInMainFile(SLoc))
+    if (SM.isInSystemHeader(SLoc))
       return true;
     const Preprocessor &PP = AST.getPreprocessor();
     if (SLoc.isMacroID() && !PP.isAtStartOfMacroExpansion(SLoc))
       return true;
   }
   return isSpecializedNodeExcluded(N);
 }
 

test/Tooling/clang-diff-ast.cpp

void macros() {
   // CHECK-NEXT: Macro(92)
   F(1, 2);
 }
 
 #ifndef GUARD
 #define GUARD
 // CHECK-NEXT: NamespaceDecl(93)
 namespace world {
-// nodes from other files are excluded, there should be no output here
+// CHECK-NEXT: NamespaceDecl
 #include "clang-diff-ast.cpp"
 }
-// CHECK-NEXT: FunctionDecl(94)
+// CHECK: FunctionDecl(197)
 void sentinel();
 #endif
 
-// CHECK: ClassTemplateDecl(97)
+// CHECK: ClassTemplateDecl(200)
 // CHECK-NEXT: TemplateTypeParmDecl
 // CHECK-NEXT: QualType
 // CHECK-NEXT: CXXRecordDecl
 template <class T> class C {
   // CHECK-NEXT: FieldDecl
   // CHECK-NEXT: TypeLoc
   T t;
 };
 
 // CHECK-NEXT: CXXRecordDecl
 // CHECK-NEXT: TypeLoc
 // CHECK-NEXT: TemplateName
 // CHECK-NEXT: TemplateArgument
 class I : C<int> {};

tools/clang-diff/ClangDiff.cpp

 }
 
 static unsigned printHtmlForNode(raw_ostream &OS, const diff::ASTDiff &Diff,
                                  bool IsLeft,  diff::NodeRef Node,
                                  unsigned Offset) {
   char MyTag, OtherTag;
   diff::NodeId LeftId, RightId;
   diff::SyntaxTree &Tree = Node.getTree();
+  const SourceManager &SM = Tree.getASTContext().getSourceManager();
+  SourceLocation SLoc = Node.getSourceRange().getBegin();
+  if (SLoc.isValid() && !SM.isInMainFile(SLoc))
+    return Offset;
   const diff::Node *Target = Diff.getMapped(Node);
   diff::NodeId TargetId = Target ? Target->getId() : diff::NodeId();
   if (IsLeft) {
     MyTag = 'L';
     OtherTag = 'R';
     LeftId = Node.getId();
     RightId = TargetId;
   } else {
     MyTag = 'R';
     OtherTag = 'L';
     LeftId = TargetId;
     RightId = Node.getId();
   }
   unsigned Begin, End;
   std::tie(Begin, End) = Node.getSourceRangeOffsets();
-  const SourceManager &SM = Tree.getASTContext().getSourceManager();
   auto Code = SM.getBuffer(SM.getMainFileID())->getBuffer();
   for (; Offset < Begin; ++Offset)
     printHtml(OS, Code[Offset]);
   OS << "<span id='" << MyTag << Node.getId() << "' "
      << "tid='" << OtherTag << TargetId << "' ";
   OS << "title='";
   diff::ChangeKind Change = Diff.getNodeChange(Node);
   printHtml(OS, Node.getTypeLabel());