Bug 140145

Summary: Harden baseline JIT implementations of op_resolve_scope and op_get_from_scope against undefined scope register value
Product: WebKit Reporter: Michael Saboff <msaboff>
Component: JavaScriptCoreAssignee: Michael Saboff <msaboff>
Status: ASSIGNED ---    
Severity: Normal    
Priority: P2    
Version: 312.x   
Hardware: All   
OS: All   
Bug Depends on: 140033    
Bug Blocks:    

Description Michael Saboff 2015-01-06 13:51:54 PST
Similar to the issue in https://bugs.webkit.org/show_bug.cgi?id=140033 for op_new_func*, the DFG could dead code eliminate the use of the scope register.  Upon OSR exit to the baseline JIT, the scope register would be undefined.  The code determined to be dead by the DFG is still executed in the baseline JIT.  An inspection of the code shows that op_resolve_scope and op_get_from_scope need to be hardened against an undefined scope value.