Making the project build and speeding up jarjar with optimization #10
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The project would currently not build at all, as it already uses 1.7 features like the diamond operator. Update to 1.8 so the project can build and reasonably recent features can be used.
A common use-case for jarjar is to have rule with the format my.package.name.**, or even my.package.name.MyClass with no wildcards. Jarjar will convert that pattern to a regular expression and do regular expression matching on every symbol it scans to determine if the rule matches. This is very inefficient as most symbols will not match, and a simple prefix match can rule out the match in most cases. When parsing rules, extract the plain-text prefix of each rule, which is everything before the first wildcard. Then index all rules by their prefix in a prefix trie. This allows: - Avoiding slow regular expression matches in most cases, as jarjar can immediately observe that there is no matching prefix in the map. - Scaling in O(log(n)) with the number of rules when they have distinct prefixes (instead of O(n), as a matching prefix can be found from the trie instead of looping through all rules. This was tested to make jarjar faster on the Android codebase (running all jarjar rules to build a device back-to-back goes from 295s to 270s), while keeping outputs byte-identical, and providing significant speedups when many jarjar rules are used.
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@RemiNVG how did you get this to build? With your change Adding: to |
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