[Webkit-unassigned] [Bug 155110] New: [JSC] addStaticGlobals should emit SymbolTableEntry watchpoints to encourage constant folding in DFG

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=155110

            Bug ID: 155110
           Summary: [JSC] addStaticGlobals should emit SymbolTableEntry
                    watchpoints to encourage constant folding in DFG
    Classification: Unclassified
           Product: WebKit
           Version: WebKit Nightly Build
          Hardware: Unspecified
                OS: Unspecified
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: JavaScriptCore
          Assignee: webkit-unassigned at lists.webkit.org
          Reporter: utatane.tea at gmail.com

Now, (maybe, accidentally), addStaticGlobals does not emit SymbolTableEntry watchpoints for the added entries.
So, all the global variable lookups pointing to these static globals are not converted into constants in BytecodeGenerator: this fact leaves these lookups as GetGlobalVar.
But, static globals are not configurable. And they are typically non-writable. So they are constant in almost all the cases.

This patch initializes watchpoints for these static globals. These watchpoints allow DFG to convert these nodes into constants in DFG BytecodeParser.
These watchpoints includes some builtin operations and `undefined`!

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