406043 - Checks for varobj == scopechain in the compiler are too weak

Status: RESOLVED INCOMPLETE

(Core :: JavaScript Engine, enhancement)

Description

[Igor Bukanov]

Currently the compiler requires that varobj == scopechain for the top frame when optimizing global variables in script or doing const propagation. The purpose of the checks is to prevent the optimizations when compiling eval inside with/let blocks. This assumes that MaybeSetupFrame would do the proper job when creating the pseudo frame for the compiler. This is indeed the case when SM calls js_CompileScript as a part of eval implementation or for the debugger. But with an embedding calling JS_Compile*Script* API the checks may fail to filter out With/Call/Block objects when those objects are passed directly to API. 

Thus it would be nice to replace the checks with explict filtering based on the scope chain class. It should also allow to skip creation of pseudo-frames for the compiler and simplify the code to finish the refactoring started in bug 404935.

Comment 1

[André Bargull [:anba]]

Old bug, no longer valid, therefore closing as INCOMPLETE.