[ruby-core:113078] [Ruby master Bug#4040] SystemStackError with Hash[*a] for Large _a_
From:
"jeremyevans0 (Jeremy Evans) via ruby-core" <ruby-core@...>
Date:
2023-04-02 21:57:15 UTC
List:
ruby-core #113078
Issue #4040 has been updated by jeremyevans0 (Jeremy Evans).
I've updated my pull request to include additional optimizations for:
* cfunc: 10-15* for f(*a) and 35-40% for f(*a, **kw) if kw is empty
* send: 5-115% depending on type of call
* symproc: 5-100% depending of type of call
* method_missing: 10-115% depending on type of call
The cfunc optimization works by copying the array contents to the stack instead of using CALLER_SETUP_ARG.
The send, symproc, and method_missing optimizations are achieved by avoiding unnecessary use of CALLER_SETUP_ARG.
Hopefully these additional optimizations help offset any performance decrease from the additional checks needed to fix this issue.
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Bug #4040: SystemStackError with Hash[*a] for Large _a_
https://bugs.ruby-lang.org/issues/4040#change-102613
* Author: runpaint (Run Paint Run Run)
* Status: Open
* Priority: Normal
* Assignee: ko1 (Koichi Sasada)
* ruby -v: ruby 1.9.3dev (2010-11-09 trunk 29737) [x86_64-linux]
* Backport: 2.2: UNKNOWN, 2.3: UNKNOWN, 2.4: UNKNOWN
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=begin
I've been hesitating over whether to file a ticket about this, so please feel free to close if I've made the wrong choice.
I often use Hash[*array.flatten] in IRB to convert arrays of arrays into hashes. Today I noticed that if the array is big enough, this would raise a SystemStackError. Puzzled, I looked deeper. I assumed I was hitting the maximum number of arguments a method's argc can hold, but realised that the minimum size of the array needed to trigger this exception differed depending on whether I used IRB or not. So, presumably this is indeed exhausting the stack...
In IRB, the following is the minimal reproduction of this problem:
Hash[*130648.times.map{ 1 }]; true
I haven't looked for the minimum value needed with `ruby -e`, but the following reproduces:
ruby -e 'Hash[*1380888.times.map{ 1 }]'
I suppose this isn't technically a bug, but maybe it offers another argument for either #666 or an extension of #3131.
=end
--
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