Bug 1520129 - Remove redundant isSelfHostedBuiltin checks in GetFunctionThis / JSOP_FUNCTIONTHIS. r=anba

Differential Revision: https://phabricator.services.mozilla.com/D16536

--HG--
extra : moz-landing-system : lando

js/src/jit/BaselineCompiler.cpp

@@ -1740,8 +1740,8 @@ bool BaselineCodeGen<Handler>::emit_JSOP_FUNCTIONTHIS() {
 
   frame.pushThis();
 
-  // In strict mode code or self-hosted functions, |this| is left alone.
-  if (script->strict() || (function() && function()->isSelfHostedBuiltin())) {
+  // In strict mode code, |this| is left alone.
+  if (script->strict()) {
     return true;
   }
 

js/src/jit/IonBuilder.cpp

@@ -12852,8 +12852,8 @@ AbortReasonOr<Ok> IonBuilder::jsop_functionthis() {
   MOZ_ASSERT(info().funMaybeLazy());
   MOZ_ASSERT(!info().funMaybeLazy()->isArrow());
 
-  if (script()->strict() || info().funMaybeLazy()->isSelfHostedBuiltin()) {
-    // No need to wrap primitive |this| in strict mode or self-hosted code.
+  if (script()->strict()) {
+    // No need to wrap primitive |this| in strict mode.
     current->pushSlot(info().thisSlot());
     return Ok();
   }

js/src/vm/Interpreter.cpp

@@ -119,12 +119,14 @@ bool js::GetFunctionThis(JSContext* cx, AbstractFramePtr frame,
   MOZ_ASSERT(frame.isFunctionFrame());
   MOZ_ASSERT(!frame.callee()->isArrow());
 
-  if (frame.thisArgument().isObject() || frame.callee()->strict() ||
-      frame.callee()->isSelfHostedBuiltin()) {
+  if (frame.thisArgument().isObject() || frame.callee()->strict()) {
     res.set(frame.thisArgument());
     return true;
   }
 
+  MOZ_ASSERT(!frame.callee()->isSelfHostedBuiltin(),
+             "Self-hosted builtins must be strict");
+
   RootedValue thisv(cx, frame.thisArgument());
 
   // If there is a NSVO on environment chain, use it as basis for fallback

js/src/vm/SelfHosting.cpp

@@ -3347,6 +3347,7 @@ bool JSRuntime::cloneSelfHostedFunctionScript(JSContext* cx,
 
   MOZ_ASSERT(sourceFun->nargs() == targetFun->nargs());
   MOZ_ASSERT(sourceScript->hasRest() == targetFun->nonLazyScript()->hasRest());
+  MOZ_ASSERT(targetFun->strict(), "Self-hosted builtins must be strict");
 
   // The target function might have been relazified after its flags changed.
   targetFun->setFlags(targetFun->flags() | sourceFun->flags());