Index: clang/lib/Format/ContinuationIndenter.cpp
===================================================================
--- clang/lib/Format/ContinuationIndenter.cpp
+++ clang/lib/Format/ContinuationIndenter.cpp
@@ -1228,8 +1228,9 @@
        (PreviousNonComment->ClosesTemplateDeclaration ||
         PreviousNonComment->ClosesRequiresClause ||
         PreviousNonComment->isOneOf(
-            TT_AttributeParen, TT_AttributeSquare, TT_FunctionAnnotationRParen,
-            TT_JavaAnnotation, TT_LeadingJavaAnnotation))) ||
+            TT_AttributeParen, TT_AttributeMacro, TT_AttributeSquare,
+            TT_FunctionAnnotationRParen, TT_JavaAnnotation,
+            TT_LeadingJavaAnnotation))) ||
       (!Style.IndentWrappedFunctionNames &&
        NextNonComment->isOneOf(tok::kw_operator, TT_FunctionDeclarationName))) {
     return std::max(CurrentState.LastSpace, CurrentState.Indent);
Index: clang/lib/Format/TokenAnnotator.cpp
===================================================================
--- clang/lib/Format/TokenAnnotator.cpp
+++ clang/lib/Format/TokenAnnotator.cpp
@@ -369,7 +369,7 @@
     // Infer the role of the l_paren based on the previous token if we haven't
     // detected one yet.
     if (PrevNonComment && OpeningParen.is(TT_Unknown)) {
-      if (PrevNonComment->is(tok::kw___attribute)) {
+      if (PrevNonComment->isOneOf(tok::kw___attribute, TT_AttributeMacro)) {
         OpeningParen.setType(TT_AttributeParen);
       } else if (PrevNonComment->isOneOf(TT_TypenameMacro, tok::kw_decltype,
                                          tok::kw_typeof,
@@ -4889,8 +4889,10 @@
   }
 
   // Ensure wrapping after __attribute__((XX)) and @interface etc.
-  if (Left.is(TT_AttributeParen) && Right.is(TT_ObjCDecl))
+  if (Left.isOneOf(TT_AttributeMacro, TT_AttributeParen) &&
+      Right.is(TT_ObjCDecl)) {
     return true;
+  }
 
   if (Left.is(TT_LambdaLBrace)) {
     if (IsFunctionArgument(Left) &&
Index: clang/unittests/Format/FormatTestObjC.cpp
===================================================================
--- clang/unittests/Format/FormatTestObjC.cpp
+++ clang/unittests/Format/FormatTestObjC.cpp
@@ -1489,6 +1489,9 @@
 }
 
 TEST_F(FormatTestObjC, Attributes) {
+  Style.AttributeMacros.push_back("ATTRIBUTE_MACRO");
+
+  // Check '__attribute__' macro directly.
   verifyFormat("__attribute__((objc_subclassing_restricted))\n"
                "@interface Foo\n"
                "@end");
@@ -1498,6 +1501,41 @@
   verifyFormat("__attribute__((objc_subclassing_restricted))\n"
                "@implementation Foo\n"
                "@end");
+
+  // Check AttributeMacro gets treated the same, with or without parentheses.
+  verifyFormat("ATTRIBUTE_MACRO\n"
+               "@interface Foo\n"
+               "@end");
+  verifyFormat("ATTRIBUTE_MACRO(X)\n"
+               "@interface Foo\n"
+               "@end");
+
+  // Indenter also needs to understand multiple attribute macros.
+  verifyFormat("ATTRIBUTE_MACRO(X) ATTRIBUTE_MACRO\n"
+               "@interface Foo\n"
+               "@end");
+  verifyFormat("ATTRIBUTE_MACRO ATTRIBUTE_MACRO(X)\n"
+               "@interface Foo\n"
+               "@end");
+
+  Style.ColumnLimit = 30;
+  verifyFormat("ATTRIBUTE_MACRO(X)\n"
+               "ATTRIBUTE_MACRO\n"
+               "@interface Foo\n"
+               "@end");
+  // Note: the following -should- break across multiple lines, but doesn't.
+  // This is added to acknowledge the behavior, but it should be improved.
+  verifyFormat("ATTRIBUTE_MACRO ATTRIBUTE_MACRO(X)\n"
+               "@interface Foo\n"
+               "@end");
+
+  Style.ColumnLimit = 0;
+  verifyFormat("ATTRIBUTE_MACRO(X) ATTRIBUTE_MACRO\n"
+               "@interface Foo\n"
+               "@end");
+  verifyFormat("ATTRIBUTE_MACRO ATTRIBUTE_MACRO(X)\n"
+               "@interface Foo\n"
+               "@end");
 }
 
 } // end namespace
Index: clang/unittests/Format/TokenAnnotatorTest.cpp
===================================================================
--- clang/unittests/Format/TokenAnnotatorTest.cpp
+++ clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -1292,6 +1292,34 @@
   EXPECT_TOKEN(Tokens[9], tok::colon, TT_GenericSelectionColon);
 }
 
+TEST_F(TokenAnnotatorTest, UnderstandsAttributeMacros) {
+  // '__attribute__' has special handling.
+  auto Tokens = annotate("__attribute__(X) void Foo(void);");
+  ASSERT_EQ(Tokens.size(), 11u) << Tokens;
+  EXPECT_TOKEN(Tokens[0], tok::kw___attribute, TT_Unknown);
+  EXPECT_TOKEN(Tokens[1], tok::l_paren, TT_AttributeParen);
+  EXPECT_TOKEN(Tokens[3], tok::r_paren, TT_AttributeParen);
+
+  // Generic macro has no special handling in this location.
+  Tokens = annotate("A(X) void Foo(void);");
+  ASSERT_EQ(Tokens.size(), 11u) << Tokens;
+  EXPECT_TOKEN(Tokens[0], tok::identifier, TT_Unknown);
+  EXPECT_TOKEN(Tokens[1], tok::l_paren, TT_Unknown);
+  // 'TT_FunctionAnnotationRParen' doesn't seem right; fix?
+  EXPECT_TOKEN(Tokens[3], tok::r_paren, TT_FunctionAnnotationRParen);
+
+  // Add a custom AttributeMacro. Test that it has the same behavior.
+  FormatStyle Style = getLLVMStyle();
+  Style.AttributeMacros.push_back("A");
+
+  // An "AttributeMacro" gets annotated like '__attribute__'.
+  Tokens = annotate("A(X) void Foo(void);", Style);
+  ASSERT_EQ(Tokens.size(), 11u) << Tokens;
+  EXPECT_TOKEN(Tokens[0], tok::identifier, TT_AttributeMacro);
+  EXPECT_TOKEN(Tokens[1], tok::l_paren, TT_AttributeParen);
+  EXPECT_TOKEN(Tokens[3], tok::r_paren, TT_AttributeParen);
+}
+
 TEST_F(TokenAnnotatorTest, UnderstandsVerilogOperators) {
   auto Annotate = [this](llvm::StringRef Code) {
     return annotate(Code, getLLVMStyle(FormatStyle::LK_Verilog));