Bug 111506 - The DFG should mark an aliased arguments register as such in the IR
Summary: The DFG should mark an aliased arguments register as such in the IR
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: JavaScriptCore (show other bugs)
Version: 528+ (Nightly build)
Hardware: All All
: P2 Normal
Assignee: Filip Pizlo
URL:
Keywords:
Depends on: 109389
Blocks:
  Show dependency tree / graph
 
Reported: 2013-03-05 18:16 PST by Filip Pizlo
Modified: 2013-03-05 18:16 PST (History)
7 users (show)

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Description Filip Pizlo 2013-03-05 18:16:00 PST 
It currently flags it as such and then lets it sort of die (the GetLocals to it are not referenced), but this feels fragile.  We should instead make it live, but make all operations over it indicate explicitly that it is dead.  So PhantomLocals remain, GetLocals turn into PhantomLocals, and the SetLocal(PhantomArguments) should become something like SetLocalPhantomArguments, which is a no-op but indicates the start of the PhantomArgument's live range.

This is not a critical bug; it would just be nice to clean this up at some point if we have a chance.