1 files changed, 20 insertions, 5 deletions

diff --git a/js/src/vm/Interpreter.cpp b/js/src/vm/Interpreter.cpp
index 23a1ad2a5..ad9e87a50 100644
--- a/js/src/vm/Interpreter.cpp
+++ b/js/src/vm/Interpreter.cpp
@@ -261,11 +261,16 @@ SetPropertyOperation(JSContext* cx, JSOp op, HandleValue lval, HandleId id, Hand
 }
 
 static JSFunction*
-MakeDefaultConstructor(JSContext* cx, JSOp op, JSAtom* atom, HandleObject proto)
+MakeDefaultConstructor(JSContext* cx, HandleScript script, jsbytecode* pc, HandleObject proto)
 {
+    JSOp op = JSOp(*pc);
+    JSAtom* atom = script->getAtom(pc);
     bool derived = op == JSOP_DERIVEDCONSTRUCTOR;
     MOZ_ASSERT(derived == !!proto);
 
+    jssrcnote* classNote = GetSrcNote(cx, script, pc);
+    MOZ_ASSERT(classNote && SN_TYPE(classNote) == SRC_CLASS_SPAN);
+
     PropertyName* lookup = derived ? cx->names().DefaultDerivedClassConstructor
                                    : cx->names().DefaultBaseClassConstructor;
 
@@ -285,6 +290,17 @@ MakeDefaultConstructor(JSContext* cx, JSOp op, JSAtom* atom, HandleObject proto)
 
     MOZ_ASSERT(ctor->infallibleIsDefaultClassConstructor(cx));
 
+    // Create the script now, as the source span needs to be overridden for
+    // toString. Calling toString on a class constructor must not return the
+    // source for just the constructor function.
+    JSScript *ctorScript = JSFunction::getOrCreateScript(cx, ctor);
+    if (!ctorScript)
+        return nullptr;
+    uint32_t classStartOffset = GetSrcNoteOffset(classNote, 0);
+    uint32_t classEndOffset = GetSrcNoteOffset(classNote, 1);
+    ctorScript->setDefaultClassConstructorSpan(script->sourceObject(), classStartOffset,
+                                               classEndOffset);
+
     return ctor;
 }
 
@@ -4174,8 +4190,8 @@ CASE(JSOP_DERIVEDCONSTRUCTOR)
     MOZ_ASSERT(REGS.sp[-1].isObject());
     ReservedRooted<JSObject*> proto(&rootObject0, &REGS.sp[-1].toObject());
 
-    JSFunction* constructor = MakeDefaultConstructor(cx, JSOp(*REGS.pc), script->getAtom(REGS.pc),
-                                                     proto);
+    JSFunction* constructor = MakeDefaultConstructor(cx, script, REGS.pc, proto);
+
     if (!constructor)
         goto error;
 
@@ -4185,8 +4201,7 @@ END_CASE(JSOP_DERIVEDCONSTRUCTOR)
 
 CASE(JSOP_CLASSCONSTRUCTOR)
 {
-    JSFunction* constructor = MakeDefaultConstructor(cx, JSOp(*REGS.pc), script->getAtom(REGS.pc),
-                                                     nullptr);
+    JSFunction* constructor = MakeDefaultConstructor(cx, script, REGS.pc, nullptr);
     if (!constructor)
         goto error;
     PUSH_OBJECT(*constructor);