diff --git a/js/src/jit/JSONPrinter.h b/js/src/jit/JSONPrinter.h
new file mode 100644
index 000000000000..6ab4a5b9a6f8
--- /dev/null
+++ b/js/src/jit/JSONPrinter.h
@@ -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_JSONPrinter_h
+#define jit_JSONPrinter_h
+
+#ifdef JS_JITSPEW
+
+#include <stdio.h>
+
+#include "js/TypeDecls.h"
+#include "vm/Printer.h"
+
+namespace js {
+namespace jit {
+
+class JSONPrinter
+{
+  protected:
+    int indentLevel_;
+    bool first_;
+    GenericPrinter& out_;
+
+    void indent();
+
+    void property(const char* name);
+    void beginObject();
+    void beginObjectProperty(const char* name);
+    void beginListProperty(const char* name);
+    void stringValue(const char* format, ...) MOZ_FORMAT_PRINTF(2, 3);
+    void stringProperty(const char* name, const char* format, ...) MOZ_FORMAT_PRINTF(3, 4);
+    void beginStringProperty(const char* name);
+    void endStringProperty();
+    void integerValue(int value);
+    void integerProperty(const char* name, int value);
+    void endObject();
+    void endList();
+
+  public:
+    explicit JSONPrinter(GenericPrinter& out)
+      : indentLevel_(0),
+        first_(true),
+        out_(out)
+    { }
+};
+
+} // namespace jit
+} // namespace js
+
+#endif /* JS_JITSPEW */
+
+#endif /* jit_JSONPrinter_h */
diff --git a/js/src/jit/JSONSpewer.cpp b/js/src/jit/JSONSpewer.cpp
index 39d2118060f8..e9d3e8bb8876 100644
--- a/js/src/jit/JSONSpewer.cpp
+++ b/js/src/jit/JSONSpewer.cpp
@@ -21,128 +21,6 @@
 using namespace js;
 using namespace js::jit;
 
-void
-JSONSpewer::indent()
-{
-    MOZ_ASSERT(indentLevel_ >= 0);
-    out_.printf("\n");
-    for (int i = 0; i < indentLevel_; i++)
-        out_.printf("  ");
-}
-
-void
-JSONSpewer::property(const char* name)
-{
-    if (!first_)
-        out_.printf(",");
-    indent();
-    out_.printf("\"%s\":", name);
-    first_ = false;
-}
-
-void
-JSONSpewer::beginObject()
-{
-    if (!first_) {
-        out_.printf(",");
-        indent();
-    }
-    out_.printf("{");
-    indentLevel_++;
-    first_ = true;
-}
-
-void
-JSONSpewer::beginObjectProperty(const char* name)
-{
-    property(name);
-    out_.printf("{");
-    indentLevel_++;
-    first_ = true;
-}
-
-void
-JSONSpewer::beginListProperty(const char* name)
-{
-    property(name);
-    out_.printf("[");
-    first_ = true;
-}
-
-void
-JSONSpewer::beginStringProperty(const char* name)
-{
-    property(name);
-    out_.printf("\"");
-}
-
-void
-JSONSpewer::endStringProperty()
-{
-    out_.printf("\"");
-}
-
-void
-JSONSpewer::stringProperty(const char* name, const char* format, ...)
-{
-    va_list ap;
-    va_start(ap, format);
-
-    beginStringProperty(name);
-    out_.vprintf(format, ap);
-    endStringProperty();
-
-    va_end(ap);
-}
-
-void
-JSONSpewer::stringValue(const char* format, ...)
-{
-    va_list ap;
-    va_start(ap, format);
-
-    if (!first_)
-        out_.printf(",");
-    out_.printf("\"");
-    out_.vprintf(format, ap);
-    out_.printf("\"");
-
-    va_end(ap);
-    first_ = false;
-}
-
-void
-JSONSpewer::integerProperty(const char* name, int value)
-{
-    property(name);
-    out_.printf("%d", value);
-}
-
-void
-JSONSpewer::integerValue(int value)
-{
-    if (!first_)
-        out_.printf(",");
-    out_.printf("%d", value);
-    first_ = false;
-}
-
-void
-JSONSpewer::endObject()
-{
-    indentLevel_--;
-    indent();
-    out_.printf("}");
-    first_ = false;
-}
-
-void
-JSONSpewer::endList()
-{
-    out_.printf("]");
-    first_ = false;
-}
-
 void
 JSONSpewer::beginFunction(JSScript* script)
 {
@@ -172,16 +50,15 @@ JSONSpewer::spewMResumePoint(MResumePoint* rp)
     if (rp->caller())
         integerProperty("caller", rp->caller()->block()->id());
 
-    property("mode");
     switch (rp->mode()) {
       case MResumePoint::ResumeAt:
-        out_.printf("\"At\"");
+        stringProperty("mode", "%s", "At");
         break;
       case MResumePoint::ResumeAfter:
-        out_.printf("\"After\"");
+        stringProperty("mode", "%s", "After");
         break;
       case MResumePoint::Outer:
-        out_.printf("\"Outer\"");
+        stringProperty("mode", "%s", "Outer");
         break;
     }
 
@@ -374,8 +251,7 @@ JSONSpewer::spewRanges(BacktrackingAllocator* regalloc)
                     LiveRange* range = LiveRange::get(*iter);
 
                     beginObject();
-                    property("allocation");
-                    out_.printf("\"%s\"", range->bundle()->allocation().toString().get());
+                    stringProperty("allocation", "%s", range->bundle()->allocation().toString().get());
                     integerProperty("start", range->from().bits());
                     integerProperty("end", range->to().bits());
                     endObject();
diff --git a/js/src/jit/JSONSpewer.h b/js/src/jit/JSONSpewer.h
index 02f449c7ab04..45200ffa1641 100644
--- a/js/src/jit/JSONSpewer.h
+++ b/js/src/jit/JSONSpewer.h
@@ -11,8 +11,8 @@
 
 #include <stdio.h>
 
+#include "jit/JSONPrinter.h"
 #include "js/TypeDecls.h"
-#include "vm/Printer.h"
 
 namespace js {
 namespace jit {
@@ -23,33 +23,11 @@ class MIRGraph;
 class MResumePoint;
 class LNode;
 
-class JSONSpewer
+class JSONSpewer : JSONPrinter
 {
-  private:
-    int indentLevel_;
-    bool first_;
-    GenericPrinter& out_;
-
-    void indent();
-
-    void property(const char* name);
-    void beginObject();
-    void beginObjectProperty(const char* name);
-    void beginListProperty(const char* name);
-    void stringValue(const char* format, ...) MOZ_FORMAT_PRINTF(2, 3);
-    void stringProperty(const char* name, const char* format, ...) MOZ_FORMAT_PRINTF(3, 4);
-    void beginStringProperty(const char* name);
-    void endStringProperty();
-    void integerValue(int value);
-    void integerProperty(const char* name, int value);
-    void endObject();
-    void endList();
-
   public:
     explicit JSONSpewer(GenericPrinter& out)
-      : indentLevel_(0),
-        first_(true),
-        out_(out)
+      : JSONPrinter(out)
     { }
 
     void beginFunction(JSScript* script);
diff --git a/js/src/moz.build b/js/src/moz.build
index 197be027bb23..d230c2c27fbb 100644
--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -248,6 +248,7 @@ UNIFIED_SOURCES += [
     'jit/JitFrames.cpp',
     'jit/JitOptions.cpp',
     'jit/JitSpewer.cpp',
+    'jit/JSONPrinter.cpp',
     'jit/JSONSpewer.cpp',
     'jit/LICM.cpp',
     'jit/Linker.cpp',