diff -r 000000000000 -r 6474c204b198 js/src/jit/C1Spewer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit/C1Spewer.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,55 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef jit_C1Spewer_h
+#define jit_C1Spewer_h
+
+#ifdef DEBUG
+
+#include "NamespaceImports.h"
+
+#include "js/RootingAPI.h"
+
+namespace js {
+namespace jit {
+
+class MDefinition;
+class MInstruction;
+class MBasicBlock;
+class MIRGraph;
+class LinearScanAllocator;
+class LInstruction;
+
+class C1Spewer
+{
+    MIRGraph *graph;
+    HandleScript script;
+    FILE *spewout_;
+
+  public:
+    C1Spewer()
+      : graph(nullptr), script(NullPtr()), spewout_(nullptr)
+    { }
+
+    bool init(const char *path);
+    void beginFunction(MIRGraph *graph, HandleScript script);
+    void spewPass(const char *pass);
+    void spewIntervals(const char *pass, LinearScanAllocator *regalloc);
+    void endFunction();
+    void finish();
+
+  private:
+    void spewPass(FILE *fp, MBasicBlock *block);
+    void spewIntervals(FILE *fp, LinearScanAllocator *regalloc, LInstruction *ins, size_t &nextId);
+    void spewIntervals(FILE *fp, MBasicBlock *block, LinearScanAllocator *regalloc, size_t &nextId);
+};
+
+} // namespace jit
+} // namespace js
+
+#endif /* DEBUG */
+
+#endif /* jit_C1Spewer_h */