Backed out changeset 962dbeaf5c5d (bug 1238555) for opt-only jit-test failures.

js/src/frontend/BytecodeEmitter.cpp

@@ -6390,16 +6390,11 @@ BytecodeEmitter::emitFunction(ParseNode* pn, bool needsProto)
 
         SharedContext* outersc = sc;
         if (fun->isInterpretedLazy()) {
-            // We need to update the static scope chain regardless of whether
-            // the LazyScript has already been initialized, due to the case
-            // where we previously successfully compiled an inner function's
-            // lazy script but failed to compile the outer script after the
-            // fact. If we attempt to compile the outer script again, the
-            // static scope chain will be newly allocated and will mismatch
-            // the previously compiled LazyScript's.
-            ScriptSourceObject* source = &script->sourceObject()->as<ScriptSourceObject>();
-            JSObject* scope = innermostStaticScope();
-            fun->lazyScript()->setEnclosingScopeAndSource(scope, source);
+            if (!fun->lazyScript()->sourceObject()) {
+                JSObject* scope = innermostStaticScope();
+                JSObject* source = script->sourceObject();
+                fun->lazyScript()->setParent(scope, &source->as<ScriptSourceObject>());
+            }
             if (emittingRunOnceLambda)
                 fun->lazyScript()->setTreatAsRunOnce();
         } else {

js/src/jit-test/tests/gc/bug-1238555.js

@@ -1,9 +0,0 @@
-oomTest(
-  function x() {
-    try {
-      eval('let ')
-    } catch (ex) {
-      (function() {})()
-    }
-  }
-);

js/src/jsscript.cpp

@@ -4281,14 +4281,11 @@ LazyScript::resetScript()
 }
 
 void
-LazyScript::setEnclosingScopeAndSource(JSObject* enclosingScope, ScriptSourceObject* sourceObject)
+LazyScript::setParent(JSObject* enclosingScope, ScriptSourceObject* sourceObject)
 {
+    MOZ_ASSERT(!sourceObject_ && !enclosingScope_);
     MOZ_ASSERT_IF(enclosingScope, function_->compartment() == enclosingScope->compartment());
     MOZ_ASSERT(function_->compartment() == sourceObject->compartment());
-    // This method may be called to update the enclosing scope. See comment
-    // above the callsite in BytecodeEmitter::emitFunction.
-    MOZ_ASSERT_IF(sourceObject_, sourceObject_ == sourceObject && enclosingScope_);
-    MOZ_ASSERT_IF(!sourceObject_, !enclosingScope_);
 
     enclosingScope_ = enclosingScope;
     sourceObject_ = sourceObject;
@@ -4399,7 +4396,7 @@ LazyScript::Create(ExclusiveContext* cx, HandleFunction fun,
     // Set the enclosing scope of the lazy function, this would later be
     // used to define the environment when the function would be used.
     MOZ_ASSERT(!res->sourceObject());
-    res->setEnclosingScopeAndSource(enclosingScope, &sourceObjectScript->scriptSourceUnwrap());
+    res->setParent(enclosingScope, &sourceObjectScript->scriptSourceUnwrap());
 
     MOZ_ASSERT(!res->hasScript());
     if (script)

js/src/jsscript.h

@@ -2272,7 +2272,7 @@ class LazyScript : public gc::TenuredCell
         return (p_.version == JS_BIT(8) - 1) ? JSVERSION_UNKNOWN : JSVersion(p_.version);
     }
 
-    void setEnclosingScopeAndSource(JSObject* enclosingScope, ScriptSourceObject* sourceObject);
+    void setParent(JSObject* enclosingScope, ScriptSourceObject* sourceObject);
 
     uint32_t numFreeVariables() const {
         return p_.numFreeVariables;