I work on a binary instrumentation platform for Android. Our platform
instruments binary code to add things like logging, dynamic analysis,
inline reference monitors, etc...

Quite frequently, I'll rewrite a Dalvik class file, and run it on a
device. Sometimes it will fail immediately upon installation and the
verifier will give an occasionally useful error. But sometimes I don't
get verification errors until runtime.

Instead, I'll get strange errors that I'm not sure how to debug.

W/dalvikvm( 2658): VFY: copy1 v1<-v18 type=-1531563544 cat=1
W/dalvikvm( 2658): VFY: rejecting opcode 0x02 at 0x0091
W/dalvikvm( 2658): VFY: rejected
W/dalvikvm( 2658): Verifier rejected class

(I've replace full classpaths with ellipses for anonymity of the app.)

Unfortunately, debugging these kinds of errors is hard: these errors
aren't very descriptive. I'd like to know one of the following things:

- Could someone point me into the source code where these various
errors are thrown so I can read the interpreter's implementation and
try to tease out what individual opcode errors correspond to?
   - E.g., I suspect that in this case it's because of a register type
mismatch after a register verify path
   - I'd suspect that code would be somewhere like this:

  - Is there any way I can run the verifier without booting up a
device, can I get a finer grained / better error message for bytecode
verification errors.

  - Is there a debug flag for the verifier that I can turn on to be
able to get a better idea about what's happening?


Kris Micinski

You received this message because you are subscribed to the Google Groups "android-platform" group.
To unsubscribe from this group and stop receiving emails from it, send an email to
To post to this group, send email to
Visit this group at
For more options, visit

Search Discussions

Discussion Posts

Follow ups

Related Discussions

Discussion Navigation
viewthread | post
posts ‹ prev | 1 of 2 | next ›
Discussion Overview
groupandroid-platform @
postedSep 10, '15 at 2:54p
activeSep 10, '15 at 2:54p

1 user in discussion

Kristopher Micinski: 2 posts



site design / logo © 2019 Grokbase