samsung rom art file

Question

I used Samsung ROM, install a apk when it used dex2oat, when parameter is --art-fd=13, there is a *.art file, then app crash. when parameter is --art-fd=-1, there is not a *.art file, then app runs normal.

I want to know what is art file. anybody help?

I open the *.art file with hex editor, this file is not a ELF file, header is "oat\n109". OAT file is a ELF file. this file maybe is created by Samsung.

Answer 1

My guess is that you're running your byte-code though an obfuscator/shrinker resulting in invalid dex code. The dalvik vm is more lenient than art is about such code. The OAT compiled version of your code is likely crashing when executed by the android runtime. When you run dex2oat with --art-fd=-1 it probably doesn't write anything out causing the android runtime to fall back to simply executing the dex code. Just a guess.