diff --git a/tools/aapt2/Resources.proto b/tools/aapt2/Resources.proto
index 4247ec5..b45c040 100644
--- a/tools/aapt2/Resources.proto
+++ b/tools/aapt2/Resources.proto
@@ -273,6 +273,7 @@
     Styleable styleable = 3;
     Array array = 4;
     Plural plural = 5;
+    MacroBody macro = 6;
   }
 }
 
@@ -304,6 +305,13 @@
 
   // Whether this reference is dynamic.
   Boolean is_dynamic = 5;
+
+  // The type flags used when compiling the reference. Used for substituting the contents of macros.
+  uint32 type_flags = 6;
+
+  // Whether raw string values would have been accepted in place of this reference definition. Used
+  // for substituting the contents of macros.
+  bool allow_raw = 7;
 }
 
 // A value that represents an ID. This is just a placeholder, as ID values are used to occupy a
@@ -591,3 +599,32 @@
   // The optional interpreted/compiled version of the `value` string.
   Item compiled_item = 6;
 }
+
+message MacroBody {
+  string raw_string = 1;
+  StyleString style_string = 2;
+  repeated UntranslatableSection untranslatable_sections = 3;
+  repeated NamespaceAlias namespace_stack = 4;
+  SourcePosition source = 5;
+}
+
+message NamespaceAlias {
+  string prefix = 1;
+  string package_name = 2;
+  bool is_private = 3;
+}
+
+message StyleString {
+  message Span {
+    string name = 1;
+    uint32 start_index = 2;
+    uint32 end_index = 3;
+  }
+  string str = 1;
+  repeated Span spans = 2;
+}
+
+message UntranslatableSection {
+  uint64 start_index = 1;
+  uint64 end_index = 2;
+}
\ No newline at end of file