diff --git a/js/src/frontend/BytecodeCompiler.cpp b/js/src/frontend/BytecodeCompiler.cpp
index 6501bd3fc9e..20c2d73af4d 100644
--- a/js/src/frontend/BytecodeCompiler.cpp
+++ b/js/src/frontend/BytecodeCompiler.cpp
@@ -190,6 +190,9 @@ frontend::CompileScript(JSContext *cx, HandleObject scopeChain, StackFrame *call
         parser.freeTree(pn);
     }
 
+    if (tokenStream.hasSourceMap())
+        ss->setSourceMap(tokenStream.releaseSourceMap());
+
 #if JS_HAS_XML_SUPPORT
     /*
      * Prevent XML data theft via <script src="http://victim.com/foo.xml">.
@@ -338,6 +341,9 @@ frontend::CompileFunctionBody(JSContext *cx, HandleFunction fun, CompileOptions
         pn = fn->pn_body;
     }
 
+    if (parser.tokenStream.hasSourceMap())
+        ss->setSourceMap(parser.tokenStream.releaseSourceMap());
+
     if (!EmitFunctionScript(cx, &funbce, pn))
         return false;
 
diff --git a/js/src/frontend/TokenStream.cpp b/js/src/frontend/TokenStream.cpp
index 1b2396fcc12..8e3b3452dce 100644
--- a/js/src/frontend/TokenStream.cpp
+++ b/js/src/frontend/TokenStream.cpp
@@ -1246,17 +1246,16 @@ TokenStream::getAtSourceMappingURL()
              * we should stop and drop everything for, though. */
             return true;
 
-        int len = tokenbuf.length();
+        size_t sourceMapLength = tokenbuf.length();
 
         if (sourceMap)
             cx->free_(sourceMap);
-        sourceMap = (jschar *) cx->malloc_(sizeof(jschar) * (len + 1));
+        sourceMap = static_cast<jschar *>(cx->malloc_(sizeof(jschar) * (sourceMapLength + 1)));
         if (!sourceMap)
             return false;
 
-        for (int i = 0; i < len; i++)
-            sourceMap[i] = tokenbuf[i];
-        sourceMap[len] = '\0';
+        PodCopy(sourceMap, tokenbuf.begin(), sourceMapLength);
+        sourceMap[sourceMapLength] = '\0';
     }
     return true;
 }
diff --git a/js/src/frontend/TokenStream.h b/js/src/frontend/TokenStream.h
index 15d6dbe5356..de5793be885 100644
--- a/js/src/frontend/TokenStream.h
+++ b/js/src/frontend/TokenStream.h
@@ -679,11 +679,16 @@ class TokenStream
      */
     size_t endOffset(const Token &tok);
 
+    bool hasSourceMap() const {
+        return sourceMap != NULL;
+    }
+
     /*
      * Give up responsibility for managing the sourceMap filename's memory.
      */
-    const jschar *releaseSourceMap() {
-        const jschar* sm = sourceMap;
+    jschar *releaseSourceMap() {
+        JS_ASSERT(hasSourceMap());
+        jschar *sm = sourceMap;
         sourceMap = NULL;
         return sm;
     }
diff --git a/js/src/jsapi-tests/testXDR.cpp b/js/src/jsapi-tests/testXDR.cpp
index 0633fc048bc..6407ad5d5cc 100644
--- a/js/src/jsapi-tests/testXDR.cpp
+++ b/js/src/jsapi-tests/testXDR.cpp
@@ -8,6 +8,7 @@
 
 #include "tests.h"
 #include "jsscript.h"
+#include "jsstr.h"
 
 static JSScript *
 CompileScriptForPrincipalsVersionOrigin(JSContext *cx, JS::HandleObject obj,
@@ -254,3 +255,40 @@ BEGIN_TEST(testXDR_source)
     return true;
 }
 END_TEST(testXDR_source)
+
+BEGIN_TEST(testXDR_sourceMap)
+{
+    const char *sourceMaps[] = {
+        "http://example.com/source-map.json",
+        "file:///var/source-map.json",
+        NULL
+    };
+    for (const char **sm = sourceMaps; *sm; sm++) {
+        JSScript *script = JS_CompileScript(cx, global, "", 0, __FILE__, __LINE__);
+        CHECK(script);
+
+        size_t len = strlen(*sm);
+        jschar *expected = js::InflateString(cx, *sm, &len);
+        CHECK(expected);
+
+        // The script source takes responsibility of free'ing |expected|.
+        script->scriptSource()->setSourceMap(expected);
+        script = FreezeThaw(cx, script);
+        CHECK(script);
+        CHECK(script->scriptSource());
+        CHECK(script->scriptSource()->hasSourceMap());
+
+        const jschar *actual = script->scriptSource()->sourceMap();
+        CHECK(actual);
+
+        while (*expected) {
+            CHECK(*actual);
+            CHECK(*expected == *actual);
+            expected++;
+            actual++;
+        }
+        CHECK(!*actual);
+    }
+    return true;
+}
+END_TEST(testXDR_sourceMap)
diff --git a/js/src/jscompartment.cpp b/js/src/jscompartment.cpp
index f8c5bb63e58..f697782d0b8 100644
--- a/js/src/jscompartment.cpp
+++ b/js/src/jscompartment.cpp
@@ -67,7 +67,6 @@ JSCompartment::JSCompartment(JSRuntime *rt)
     debugModeBits(rt->debugMode ? DebugFromC : 0),
     watchpointMap(NULL),
     scriptCountsMap(NULL),
-    sourceMapMap(NULL),
     debugScriptMap(NULL)
 {
     setGCMaxMallocBytes(rt->gcMaxMallocBytes);
@@ -77,7 +76,6 @@ JSCompartment::~JSCompartment()
 {
     Foreground::delete_(watchpointMap);
     Foreground::delete_(scriptCountsMap);
-    Foreground::delete_(sourceMapMap);
     Foreground::delete_(debugScriptMap);
 }
 
diff --git a/js/src/jscompartment.h b/js/src/jscompartment.h
index 3e928ce8d2a..2ff43f78816 100644
--- a/js/src/jscompartment.h
+++ b/js/src/jscompartment.h
@@ -418,8 +418,6 @@ struct JSCompartment
 
     js::ScriptCountsMap *scriptCountsMap;
 
-    js::SourceMapMap *sourceMapMap;
-
     js::DebugScriptMap *debugScriptMap;
 };
 
diff --git a/js/src/jsdbgapi.cpp b/js/src/jsdbgapi.cpp
index c13f44b80c8..00705a18658 100644
--- a/js/src/jsdbgapi.cpp
+++ b/js/src/jsdbgapi.cpp
@@ -695,7 +695,9 @@ JS_GetScriptFilename(JSContext *cx, JSScript *script)
 JS_PUBLIC_API(const jschar *)
 JS_GetScriptSourceMap(JSContext *cx, JSScript *script)
 {
-    return script->hasSourceMap ? script->getSourceMap() : NULL;
+    ScriptSource *source = script->scriptSource();
+    JS_ASSERT(source);
+    return source->hasSourceMap() ? source->sourceMap() : NULL;
 }
 
 JS_PUBLIC_API(unsigned)
diff --git a/js/src/jsscript.cpp b/js/src/jsscript.cpp
index 894e20c686f..fa7b70a3f65 100644
--- a/js/src/jsscript.cpp
+++ b/js/src/jsscript.cpp
@@ -908,61 +908,6 @@ JSScript::destroyScriptCounts(FreeOp *fop)
     }
 }
 
-bool
-JSScript::setSourceMap(JSContext *cx, jschar *sourceMap)
-{
-    JS_ASSERT(!hasSourceMap);
-
-    /* Create compartment's sourceMapMap if necessary. */
-    SourceMapMap *map = compartment()->sourceMapMap;
-    if (!map) {
-        map = cx->new_<SourceMapMap>();
-        if (!map || !map->init()) {
-            cx->delete_(map);
-            return false;
-        }
-        compartment()->sourceMapMap = map;
-    }
-
-    if (!map->putNew(this, sourceMap))
-        return false;
-
-    hasSourceMap = true; // safe to set this;  we can't fail after this point
-
-    return true;
-}
-
-jschar *
-JSScript::getSourceMap() {
-    JS_ASSERT(hasSourceMap);
-    SourceMapMap *map = compartment()->sourceMapMap;
-    JS_ASSERT(map);
-    SourceMapMap::Ptr p = map->lookup(this);
-    JS_ASSERT(p);
-    return p->value;
-}
-
-jschar *
-JSScript::releaseSourceMap()
-{
-    JS_ASSERT(hasSourceMap);
-    SourceMapMap *map = compartment()->sourceMapMap;
-    JS_ASSERT(map);
-    SourceMapMap::Ptr p = map->lookup(this);
-    JS_ASSERT(p);
-    jschar *sourceMap = p->value;
-    map->remove(p);
-    hasSourceMap = false;
-    return sourceMap;
-}
-
-void
-JSScript::destroySourceMap(FreeOp *fop)
-{
-    if (hasSourceMap)
-        fop->free_(releaseSourceMap());
-}
-
 #ifdef JS_THREADSAFE
 void
 SourceCompressorThread::compressorThread(void *arg)
@@ -1285,6 +1230,7 @@ ScriptSource::destroy(JSRuntime *rt)
 {
     JS_ASSERT(ready());
     rt->free_(data.compressed);
+    rt->free_(sourceMap_);
 #ifdef DEBUG
     ready_ = false;
 #endif
@@ -1347,6 +1293,31 @@ ScriptSource::performXDR(XDRState<mode> *xdr)
         argumentsNotIncluded_ = argumentsNotIncluded;
     }
 
+    uint8_t haveSourceMap = hasSourceMap();
+    if (!xdr->codeUint8(&haveSourceMap))
+        return false;
+
+    if (haveSourceMap) {
+        uint32_t sourceMapLen = (mode == XDR_DECODE) ? 0 : js_strlen(sourceMap_);
+        if (!xdr->codeUint32(&sourceMapLen))
+            return false;
+
+        if (mode == XDR_DECODE) {
+            size_t byteLen = (sourceMapLen + 1) * sizeof(jschar);
+            sourceMap_ = static_cast<jschar *>(xdr->cx()->malloc_(byteLen));
+            if (!sourceMap_)
+                return false;
+        }
+        if (!xdr->codeChars(sourceMap_, sourceMapLen)) {
+            if (mode == XDR_DECODE) {
+                xdr->cx()->free_(sourceMap_);
+                sourceMap_ = NULL;
+            }
+            return false;
+        }
+        sourceMap_[sourceMapLen] = '\0';
+    }
+
 #ifdef DEBUG
     if (mode == XDR_DECODE)
         ready_ = true;
@@ -1355,6 +1326,21 @@ ScriptSource::performXDR(XDRState<mode> *xdr)
     return true;
 }
 
+void
+ScriptSource::setSourceMap(jschar *sm)
+{
+    JS_ASSERT(!hasSourceMap());
+    JS_ASSERT(sm);
+    sourceMap_ = sm;
+}
+
+const jschar *
+ScriptSource::sourceMap()
+{
+    JS_ASSERT(hasSourceMap());
+    return sourceMap_;
+}
+
 /*
  * Shared script filename management.
  */
@@ -1749,14 +1735,6 @@ JSScript::fullyInitFromEmitter(JSContext *cx, Handle<JSScript*> script, Bytecode
     }
     script->nslots = script->nfixed + bce->maxStackDepth;
 
-    jschar *sourceMap = (jschar *) bce->parser->tokenStream.releaseSourceMap();
-    if (sourceMap) {
-        if (!script->setSourceMap(cx, sourceMap)) {
-            cx->free_(sourceMap);
-            return false;
-        }
-    }
-
     if (!FinishTakingSrcNotes(cx, bce, script->notes()))
         return false;
     if (bce->ntrynotes != 0)
@@ -1915,7 +1893,6 @@ JSScript::finalize(FreeOp *fop)
 #endif
 
     destroyScriptCounts(fop);
-    destroySourceMap(fop);
     destroyDebugScript(fop);
     scriptSource_->decref(fop->runtime());
 
diff --git a/js/src/jsscript.h b/js/src/jsscript.h
index 4b1e4d41ab5..8aad2a13943 100644
--- a/js/src/jsscript.h
+++ b/js/src/jsscript.h
@@ -302,11 +302,6 @@ typedef HashMap<JSScript *,
                 DefaultHasher<JSScript *>,
                 SystemAllocPolicy> ScriptCountsMap;
 
-typedef HashMap<JSScript *,
-                jschar *,
-                DefaultHasher<JSScript *>,
-                SystemAllocPolicy> SourceMapMap;
-
 class DebugScript
 {
     friend struct ::JSScript;
@@ -542,8 +537,6 @@ struct JSScript : public js::gc::Cell
     bool            isGeneratorExp:1; /* is a generator expression */
     bool            hasScriptCounts:1;/* script has an entry in
                                          JSCompartment::scriptCountsMap */
-    bool            hasSourceMap:1;   /* script has an entry in
-                                         JSCompartment::sourceMapMap */
     bool            hasDebugScript:1; /* script has an entry in
                                          JSCompartment::debugScriptMap */
 
@@ -735,11 +728,6 @@ struct JSScript : public js::gc::Cell
     js::ScriptCounts releaseScriptCounts();
     void destroyScriptCounts(js::FreeOp *fop);
 
-    bool setSourceMap(JSContext *cx, jschar *sourceMap);
-    jschar *getSourceMap();
-    jschar *releaseSourceMap();
-    void destroySourceMap(js::FreeOp *fop);
-
     jsbytecode *main() {
         return code + mainOffset;
     }
@@ -989,6 +977,7 @@ struct ScriptSource
     uint32_t refs;
     uint32_t length_;
     uint32_t compressedLength_;
+    jschar *sourceMap_;
 
     // True if we can call JSRuntime::sourceHook to load the source on
     // demand. If sourceRetrievable_ and hasSourceData() are false, it is not
@@ -1004,6 +993,7 @@ struct ScriptSource
       : refs(0),
         length_(0),
         compressedLength_(0),
+        sourceMap_(NULL),
         sourceRetrievable_(false),
         argumentsNotIncluded_(false)
 #ifdef DEBUG
@@ -1045,6 +1035,11 @@ struct ScriptSource
     template <XDRMode mode>
     bool performXDR(XDRState<mode> *xdr);
 
+    // Source maps
+    void setSourceMap(jschar *sm);
+    const jschar *sourceMap();
+    bool hasSourceMap() const { return sourceMap_ != NULL; }
+
   private:
     void destroy(JSRuntime *rt);
     bool compressed() { return compressedLength_ != 0; }
diff --git a/js/src/vm/Xdr.h b/js/src/vm/Xdr.h
index c524f31e1ca..c26ed1160d4 100644
--- a/js/src/vm/Xdr.h
+++ b/js/src/vm/Xdr.h
@@ -25,7 +25,7 @@ namespace js {
  * and saved versions. If deserialization fails, the data should be
  * invalidated if possible.
  */
-static const uint32_t XDR_BYTECODE_VERSION = uint32_t(0xb973c0de - 128);
+static const uint32_t XDR_BYTECODE_VERSION = uint32_t(0xb973c0de - 129);
 
 class XDRBuffer {
   public: