[LLVMdev] New ARM disassembler - unpredictable instructions

[Owen Anderson]

On Aug 11, 2011, at 1:32 AM, James Molloy wrote:

> Hi,
>  
> I’m looking at the new ARM disassembler, and performing testing to see if there are any obvious bugs I can fix. Overall it looks really nice – I’ve only found one obvious bug that I’m packaging up a patch for now.

Glad you're liking it!  I haven't really done comprehensive testing yet—it passes all the decoding tests that the previous disassembler passed, but I'm sure there are many cases that it does not yet get right.  Patches welcome.

> Currently it does not provide information as to whether a particular bitpattern was UNPREDICTABLE or not. For example, an invalid bitpattern may return correct disassembly for an alternative, predictable instruction meaning that the sequence X -> disassemble -> assemble -> Y could end up with X being different to Y.

Can you give an example of this?

--Owen
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