From 8062fc711c83d1d031585ec20a526b796b321c06 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 14 Mar 2021 16:41:00 +0100
Subject: [PATCH] LibJS: Add arguments.callee to our hack arguments object

arguments.callee refers to the currently executing function.
---
 Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h | 1 +
 Userland/Libraries/LibJS/Runtime/VM.cpp                | 3 +++
 Userland/Libraries/LibJS/Runtime/VM.h                  | 1 +
 3 files changed, 5 insertions(+)

diff --git a/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h b/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
index f77911048e..dbc332144a 100644
--- a/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
+++ b/Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h
@@ -75,6 +75,7 @@ namespace JS {
     P(bind)                                  \
     P(byteLength)                            \
     P(call)                                  \
+    P(callee)                                \
     P(cbrt)                                  \
     P(ceil)                                  \
     P(charAt)                                \
diff --git a/Userland/Libraries/LibJS/Runtime/VM.cpp b/Userland/Libraries/LibJS/Runtime/VM.cpp
index fe83987150..afaeaefed2 100644
--- a/Userland/Libraries/LibJS/Runtime/VM.cpp
+++ b/Userland/Libraries/LibJS/Runtime/VM.cpp
@@ -175,6 +175,7 @@ Value VM::get_variable(const FlyString& name, GlobalObject& global_object)
                 return possible_match.value().value;
             if (!call_frame().arguments_object) {
                 call_frame().arguments_object = Array::create(global_object);
+                call_frame().arguments_object->put(names.callee, call_frame().callee);
                 for (auto argument : call_frame().arguments) {
                     call_frame().arguments_object->indexed_properties().append(argument);
                 }
@@ -211,6 +212,7 @@ Reference VM::get_reference(const FlyString& name)
 Value VM::construct(Function& function, Function& new_target, Optional<MarkedValueList> arguments, GlobalObject& global_object)
 {
     CallFrame call_frame;
+    call_frame.callee = &function;
     call_frame.current_node = current_node();
     call_frame.is_strict_mode = function.is_strict_mode();
 
@@ -335,6 +337,7 @@ Value VM::call_internal(Function& function, Value this_value, Optional<MarkedVal
     VERIFY(!exception());
 
     CallFrame call_frame;
+    call_frame.callee = &function;
     call_frame.current_node = current_node();
     call_frame.is_strict_mode = function.is_strict_mode();
     call_frame.function_name = function.name();
diff --git a/Userland/Libraries/LibJS/Runtime/VM.h b/Userland/Libraries/LibJS/Runtime/VM.h
index 7313e9301a..1dca17e66f 100644
--- a/Userland/Libraries/LibJS/Runtime/VM.h
+++ b/Userland/Libraries/LibJS/Runtime/VM.h
@@ -58,6 +58,7 @@ struct ScopeFrame {
 struct CallFrame {
     const ASTNode* current_node;
     FlyString function_name;
+    Value callee;
     Value this_value;
     Vector<Value> arguments;
     Array* arguments_object { nullptr };