Avoid ClassNode construction for classes that do not get instrumented #6152
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According to https://asm.ow2.io/performance.html, using a ClassReader is a lot faster for reading basic class metadata than creating a ClassNode. This is because to create a ClassNode, every single byte of the class file needs to be visited, including method instructions. For ClassReader, a lot of the work is done lazily. Previously, a ClassNode object was constructed for every class loaded by SandboxClassLoaer, regardless of whether or not it was instrumented. Instead, use a ClassReader approach to determine whether or not a class needs to be instrumented, and then build the ClassNode if it needs to be instrumented. This should improve performance for larger tests that load a lot of non-Android classes. PiperOrigin-RevId: 351251828
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Avoid ClassNode construction for classes that do not get instrumented
According to https://asm.ow2.io/performance.html, using a ClassReader is a lot
faster for reading basic class metadata than creating a ClassNode. This is
because to create a ClassNode, every single byte of the class file needs to be
visited, including method instructions. For ClassReader, a lot of the work is
done lazily. Previously, a ClassNode object was constructed for every class
loaded by SandboxClassLoaer, regardless of whether or not it was instrumented.
Instead, use a ClassReader approach to determine whether or not a class needs
to be instrumented, and then build the ClassNode if it needs to be
instrumented. This should improve performance for larger tests that load a lot
of non-Android classes.