diff --git a/gcc/jit/jit-common.h b/gcc/jit/jit-common.h
new file mode 100644
index 0000000..58e4a8c
--- /dev/null
+++ b/gcc/jit/jit-common.h
@@ -0,0 +1,182 @@
+/* Core of implementation of libgccjit.so
+   Copyright (C) 2013-2014 Free Software Foundation, Inc.
+   Contributed by David Malcolm <dmalcolm@redhat.com>.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef JIT_COMMON_H
+#define JIT_COMMON_H
+
+#include "libgccjit.h"
+
+#include "tree.h"
+#include "tree-iterator.h"
+
+#ifdef GCC_VERSION
+#if GCC_VERSION >= 4001
+#define GNU_PRINTF(M, N) __attribute__ ((format (gnu_printf, (M), (N))))
+#else
+#define GNU_PRINTF(M, N)
+#endif
+#endif
+
+const int NUM_GCC_JIT_TYPES = GCC_JIT_TYPE_FILE_PTR + 1;
+
+/* This comment is included by the docs.
+
+   In order to allow jit objects to be usable outside of a compile
+   whilst working with the existing structure of GCC's code the
+   C API is implemented in terms of a gcc::jit::recording::context,
+   which records the calls made to it.
+
+   When a gcc_jit_context is compiled, the recording context creates a
+   playback context.  The playback context invokes the bulk of the GCC
+   code, and within the "frontend" parsing hook, plays back the recorded
+   API calls, creating GCC tree objects.
+
+   So there are two parallel families of classes: those relating to
+   recording, and those relating to playback:
+
+   * Visibility: recording objects are exposed back to client code,
+     whereas playback objects are internal to the library.
+
+   * Lifetime: recording objects have a lifetime equal to that of the
+     recording context that created them, whereas playback objects only
+     exist within the frontend hook.
+
+   * Memory allocation: recording objects are allocated by the recording
+     context, and automatically freed by it when the context is released,
+     whereas playback objects are allocated within the GC heap, and
+     garbage-collected; they can own GC-references.
+
+   * Integration with rest of GCC: recording objects are unrelated to the
+     rest of GCC, whereas playback objects are wrappers around "tree"
+     instances.  Hence you can't ask a recording rvalue or lvalue what its
+     type is, whereas you can for a playback rvalue of lvalue (since it
+     can work with the underlying GCC tree nodes).
+
+   * Instancing: There can be multiple recording contexts "alive" at once
+     (albeit it only one compiling at once), whereas there can only be one
+     playback context alive at one time (since it interacts with the GC).
+
+   Ultimately if GCC could support multiple GC heaps and contexts, and
+   finer-grained initialization, then this recording vs playback
+   distinction could be eliminated.
+
+   During a playback, we associate objects from the recording with
+   their counterparts during this playback.  For simplicity, we store this
+   within the recording objects, as ``void *m_playback_obj``, casting it to
+   the appropriate playback object subclass.  For these casts to make
+   sense, the two class hierarchies need to have the same structure.
+
+   Note that the playback objects that ``m_playback_obj`` points to are
+   GC-allocated, but the recording objects don't own references:
+   these associations only exist within a part of the code where
+   the GC doesn't collect, and are set back to NULL before the GC can
+   run.
+
+   End of comment for inclusion in the docs.  */
+
+namespace gcc {
+
+namespace jit {
+
+class result;
+class dump;
+
+namespace recording {
+
+  /* Recording types.  */
+
+  /* Indentation indicates inheritance: */
+  class context;
+  class builtins_manager; // declared within jit-builtins.h
+  class memento;
+    class string;
+    class location;
+    class type;
+      class function_type;
+      class compound_type;
+        class struct_;
+	class union_;
+    class field;
+    class fields;
+    class function;
+    class block;
+    class rvalue;
+      class lvalue;
+        class local;
+	class global;
+        class param;
+    class statement;
+
+  /* End of recording types. */
+}
+
+namespace playback {
+  /* Playback types.  */
+
+  /* Indentation indicates inheritance: */
+  class context;
+  class wrapper;
+    class type;
+      class compound_type;
+    class field;
+    class function;
+    class block;
+    class rvalue;
+      class lvalue;
+        class param;
+    class source_file;
+    class source_line;
+    class location;
+
+  /* End of playback types. */
+}
+
+typedef playback::context replayer;
+
+class dump
+{
+public:
+  dump (recording::context &ctxt,
+	const char *filename,
+	bool update_locations);
+  ~dump ();
+
+  void write (const char *fmt, ...)
+    GNU_PRINTF(2, 3);
+
+  bool update_locations () const { return m_update_locations; }
+
+  recording::location *
+  make_location () const;
+
+private:
+  recording::context &m_ctxt;
+  const char *m_filename;
+  bool m_update_locations;
+  int m_line;
+  int m_column;
+  FILE *m_file;
+};
+
+} // namespace gcc::jit
+
+} // namespace gcc
+
+#endif /* JIT_COMMON_H */
