Hi Nethra, > On Feb 7, 2017, at 11:44 PM, Nethra Ravindran via swift-corelibs-dev > <swift-corelibs-dev@swift.org> wrote: > > > > > Hi everyone, > > I am working on https://bugs.swift.org/browse/SR-3536 > <https://bugs.swift.org/browse/SR-3536> > There is a memory leak when searching for the substring of a string using > regular expression. > > > import Foundation > > let myString = "Foo" > for _ in 1...10000 { > let _ = myString.range(of: "bar", options: .regularExpression) > } > > > From the above test case i could see that over a period of time, around 60 Mb > of memory was leaked. > > I see in String.range we eventually call NSString._createRegexForPattern. > Here we maintain a mapping between NSString and NSRegularExpression object in > NSCache<NSString, NSRegularExpression>. All the entries in the cache are > maintained in a dictionary ( _entries ) which takes the UnsafeRawPointer as > the key, which seems to be the address of the NSString Object and > NSCachedEntry as value. > > Though the pattern is of type String, it is stored in the NSCache as > NSString. And since we are storing the NSCachedEntry objects in a dictionary > indexed by the address (UnsafeRawPointer) of the NSString object, there is a > new cache entry created for each iteration ( in the test case ) though the > pattern string remains the same. > > Can someone guide me about how to go about resolving this issue. > >
Looks like you’ve done most of the analysis, so you’re already pretty much there. =) Is there some other way we could be caching the results here? - Tony > Thank you. > > - Nethra Ravindran > > > _______________________________________________ > swift-corelibs-dev mailing list > swift-corelibs-dev@swift.org > https://lists.swift.org/mailman/listinfo/swift-corelibs-dev
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