Open Bug 1469383 Opened Last year Updated Last year
Duplicate stub attachment for Get
Prop in browser tests
CacheIR supports detecting duplicated stubs to avoid creating an IC chain full of duplication that doesn't actually guard anything new. This is typically a small performance issue too. It would be nice if we could eventually assert that duplicate stubs never get attached on the chain. Right now, we have gotten increasingly close; shell tests appear to pass without duplication occurring. I tested with this patch  on try  and found the assertion fails in some places, always seemingly with the following backtrace: 0 libxul.so!js::jit::AttachBaselineCacheIRStub(JSContext*, js::jit::CacheIRWriter const&, js::jit::CacheKind, js::jit::BaselineCacheIRStubKind, js::jit::ICStubEngine, JSScript*, js::jit::ICFallbackStub*, bool*) [BaselineCacheIRCompiler.cpp:7068d4394346dc9d4b1466243841865c326720bf : 2256 + 0x0] 1 libxul.so!js::jit::DoGetPropFallback [SharedIC.cpp:7068d4394346dc9d4b1466243841865c326720bf : 1866 + 0x28] : https://hg.mozilla.org/try/rev/998f6d710e2660f0972183878a38e0b86dc42cb0 : https://treeherder.mozilla.org/#/jobs?repo=try&revision=7068d4394346dc9d4b1466243841865c326720bf&selectedJob=183381846
Matt, are you planning on fix this bug? If so, can we assign it to you?
I am not actively working on this, and wouldn't take this on for at least a month. Given that it's P3, my inclination is to leave it unassigned right now.
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