Bug 174645

Summary: Reduce memory usage during OSR
Product: WebKit Reporter: Mark Lam <mark.lam>
Component: JavaScriptCoreAssignee: Mark Lam <mark.lam>
Status: ASSIGNED ---    
Severity: Normal CC: fpizlo, jfbastien, keith_miller, msaboff, saam, ticaiolima, webkit-bug-importer, ysuzuki
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on: 175144, 175145, 175453, 174694, 174696, 174697, 174809, 174837, 175446, 175549, 175617, 175688    
Bug Blocks:    

Description Mark Lam 2017-07-18 16:30:58 PDT
Details coming.

<rdar://problem/33183238>
Comment 1 Mark Lam 2017-07-18 16:35:58 PDT
Currently, when we have to do an OSR exit (DFG->baseline or FTL->baseline), we generate >=1kb of machine code that does the exit.  We don’t need to generate any code for every exit; we could just have one shared JIT probe that calls a C++ function that does the exit.  This would save a lot of executable memory.

This also means that supporting the JIT probe mechanism will be required in order to use the DFG and FTL going forward.  Currently, the only CPU targets that support the JIT probe are ARM, ARMv7, ARM64, x86, and x86_64.