Bug 165511

Summary:	WebAssembly: bit-pack signature and code for call_indirect
Product:	WebKit	Reporter:	JF Bastien <jfbastien>
Component:	JavaScriptCore	Assignee:	Nobody <webkit-unassigned>
Status:	ASSIGNED ---
Severity:	Normal	CC:	jfbastien, keith_miller, saam
Priority:	P2
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified
Bug Depends on:	165118, 165957
Bug Blocks:	161709

Description JF Bastien 2016-12-06 21:06:10 PST

See WasmFormat.h, CallableFunction and FunctionIndexSpace.
Uniquing signatures is required for correctness, and packing the signature into the code pointer will make call_indirect faster (it just needs to rotate the packed signature, check it's the expected value, and then mask it out before jumping).