159281 2016-06-29 16:12:52 -0700 Linked bytecode should not have save/resume 2018-07-11 01:46:22 -0700 1 1 1 Unclassified WebKit JavaScriptCore WebKit Nightly Build All All RESOLVED FIXED https://bugs.webkit.org/show_bug.cgi?id=159279 P2 Normal --- 1 fpizlo webkit-unassigned ysuzuki oldest_to_newest 1206540 0 fpizlo 2016-06-29 16:12:52 -0700 The save/resume opcodes are so unusual that they cause confusion in the bytecode liveness analysis. In particular, they don't have context-free use/def behavior and their live-in calculation cannot be expressed in terms of use/def. Normally, the use/def of a bytecode is determined just by that bytecode. Save/resume's use/def is context-sensitive: you need to look at some surrounding code to determine what they use and def. Worse, use/def is insufficient to calculate the live-in of resume. The live-in of resume is invariant: the only thing live-in is the argument token. This is an unusual rule, and would require resume to be special-cased. Linked bytecode has many clients: the bytecode liveness analysis, the LLInt, baseline JIT, and DFG parser. I think that instead of having so many special cases in linked bytecode for generators, we should do a generator conversion before even getting to linked bytecode. This will mean that linked bytecode won't have to worry about what it means to be a generator. 1206541 1 fpizlo 2016-06-29 16:13:13 -0700 Yusuke, do you have a bug that this can be duped to? 1206570 2 ysuzuki 2016-06-29 17:15:10 -0700 https://bugs.webkit.org/show_bug.cgi?id=152723 this patch will include this separated analysis change to transform save, resume to get_from_scope & put_to_scope. 1441136 3 ysuzuki 2018-07-11 01:46:22 -0700 Our generator mechanism was rewritten and this problems is gone!