Bug 880917 - Remove JS_SetVersion and version override machinery. r=luke

\o/

js/src/jsapi.cpp

@@ -125,38 +125,26 @@ JS::detail::CallMethodIfWrapped(JSContext *cx, IsAcceptableThis test, NativeImpl
 
 /*
  * This class is a version-establishing barrier at the head of a VM entry or
- * re-entry. It ensures that:
- *
- * - |newVersion| is the starting (default) version used for the context.
- * - The starting version state is not an override.
- * - Overrides in the VM session are not propagated to the caller.
+ * re-entry. It ensures that |newVersion| is the starting (default) version
+ * used for the context.
  */
 class AutoVersionAPI
 {
     JSContext   * const cx;
     JSVersion   oldDefaultVersion;
-    bool        oldHasVersionOverride;
-    JSVersion   oldVersionOverride;
     JSVersion   newVersion;
 
   public:
     AutoVersionAPI(JSContext *cx, JSVersion newVersion)
       : cx(cx),
-        oldDefaultVersion(cx->getDefaultVersion()),
-        oldHasVersionOverride(cx->isVersionOverridden()),
-        oldVersionOverride(oldHasVersionOverride ? cx->findVersion() : JSVERSION_UNKNOWN)
+        oldDefaultVersion(cx->getDefaultVersion())
     {
         this->newVersion = newVersion;
-        cx->clearVersionOverride();
         cx->setDefaultVersion(newVersion);
     }
 
     ~AutoVersionAPI() {
         cx->setDefaultVersion(oldDefaultVersion);
-        if (oldHasVersionOverride)
-            cx->overrideVersion(oldVersionOverride);
-        else
-            cx->clearVersionOverride();
     }
 
     /* The version that this scoped-entity establishes. */
@@ -1340,23 +1328,6 @@ JS_GetVersion(JSContext *cx)
     return VersionNumber(cx->findVersion());
 }
 
-JS_PUBLIC_API(JSVersion)
-JS_SetVersion(JSContext *cx, JSVersion newVersion)
-{
-    JS_ASSERT(VersionIsKnown(newVersion));
-    JS_ASSERT(!VersionHasFlags(newVersion));
-    JSVersion newVersionNumber = newVersion;
-
-    JSVersion oldVersion = cx->findVersion();
-    JSVersion oldVersionNumber = VersionNumber(oldVersion);
-    if (oldVersionNumber == newVersionNumber)
-        return oldVersionNumber; /* No override actually occurs! */
-
-    VersionCopyFlags(&newVersion, oldVersion);
-    cx->maybeOverrideVersion(newVersion);
-    return oldVersionNumber;
-}
-
 JS_PUBLIC_API(void)
 JS_SetVersionForCompartment(JSCompartment *compartment, JSVersion version)
 {

js/src/jsapi.h

@@ -1890,9 +1890,6 @@ JS_ContextIterator(JSRuntime *rt, JSContext **iterp);
 extern JS_PUBLIC_API(JSVersion)
 JS_GetVersion(JSContext *cx);
 
-extern JS_PUBLIC_API(JSVersion)
-JS_SetVersion(JSContext *cx, JSVersion version);
-
 // Mutate the version on the compartment. This is generally discouraged, but
 // necessary to support the version mutation in the js and xpc shell command
 // set.

js/src/jscntxt.cpp

@@ -1121,7 +1121,6 @@ js_HandleExecutionInterrupt(JSContext *cx)
 JSContext::JSContext(JSRuntime *rt)
   : ContextFriendFields(rt),
     defaultVersion(JSVERSION_DEFAULT),
-    hasVersionOverride(false),
     throwing(false),
     exception(UndefinedValue()),
     options_(0),

js/src/jscntxt.h

@@ -1535,8 +1535,6 @@ struct JSContext : js::ContextFriendFields,
   private:
     /* See JSContext::findVersion. */
     JSVersion           defaultVersion;      /* script compilation version */
-    JSVersion           versionOverride;     /* supercedes defaultVersion when valid */
-    bool                hasVersionOverride;
 
     /* Exception state -- the exception member is a GC root by definition. */
     bool                throwing;            /* is there a pending exception? */
@@ -1646,50 +1644,15 @@ struct JSContext : js::ContextFriendFields,
     inline js::RegExpStatics *regExpStatics();
 
   public:
-    /*
-     * The default script compilation version can be set iff there is no code running.
-     * This typically occurs via the JSAPI right after a context is constructed.
-     */
-    inline bool canSetDefaultVersion() const;
-
-    /* Force a version for future script compilation. */
-    inline void overrideVersion(JSVersion newVersion);
-
     /* Set the default script compilation version. */
     void setDefaultVersion(JSVersion version) {
         defaultVersion = version;
     }
 
-    void clearVersionOverride() { hasVersionOverride = false; }
     JSVersion getDefaultVersion() const { return defaultVersion; }
-    bool isVersionOverridden() const { return hasVersionOverride; }
-
-    JSVersion getVersionOverride() const {
-        JS_ASSERT(isVersionOverridden());
-        return versionOverride;
-    }
-
-    /*
-     * Set the default version if possible; otherwise, force the version.
-     * Return whether an override occurred.
-     */
-    inline bool maybeOverrideVersion(JSVersion newVersion);
-
-    /*
-     * If there is no code on the stack, turn the override version into the
-     * default version.
-     */
-    void maybeMigrateVersionOverride() {
-        JS_ASSERT(stack.empty());
-        if (JS_UNLIKELY(isVersionOverridden())) {
-            defaultVersion = versionOverride;
-            clearVersionOverride();
-        }
-    }
 
     /*
      * Return:
-     * - The override version, if there is an override version.
      * - The newest scripted frame's version, if there is such a frame.
      * - The version from the compartment.
      * - The default version.

js/src/jscntxtinlines.h

@@ -468,9 +468,6 @@ CallSetter(JSContext *cx, HandleObject obj, HandleId id, StrictPropertyOp op, un
 inline JSVersion
 JSContext::findVersion() const
 {
-    if (hasVersionOverride)
-        return versionOverride;
-
     if (JSScript *script = stack.currentScript(NULL, js::ContextStack::ALLOW_CROSS_COMPARTMENT))
         return script->getVersion();
 
@@ -480,31 +477,6 @@ JSContext::findVersion() const
     return defaultVersion;
 }
 
-inline bool
-JSContext::canSetDefaultVersion() const
-{
-    return !stack.hasfp() && !hasVersionOverride;
-}
-
-inline void
-JSContext::overrideVersion(JSVersion newVersion)
-{
-    JS_ASSERT(!canSetDefaultVersion());
-    versionOverride = newVersion;
-    hasVersionOverride = true;
-}
-
-inline bool
-JSContext::maybeOverrideVersion(JSVersion newVersion)
-{
-    if (canSetDefaultVersion()) {
-        setDefaultVersion(newVersion);
-        return false;
-    }
-    overrideVersion(newVersion);
-    return true;
-}
-
 inline js::LifoAlloc &
 JSContext::analysisLifoAlloc()
 {

js/src/vm/Stack.cpp

@@ -833,9 +833,6 @@ ContextStack::popSegment()
 {
     space().seg_ = seg_->prevInMemory();
     seg_ = seg_->prevInContext();
-
-    if (!seg_)
-        cx_->maybeMigrateVersionOverride();
 }
 
 bool