Re: need ideas on how to debug code generator

Ram Bhamidipaty wrote:
> I have a small code generator - for 32 bit x86 machines,
> unfortunately it has some bugs :-(. My problem is that the generated
> code fails "once in a while" sometimes it can go for 20-40 iterations
> before failing.
>
> I have a collection of test cases where I verify the correctness of
> various simple constructs -- things like load, store, add, sub, etc.
> Those all pass.
>
> The test case in question generates a code sequence of about 400
> bytes. It fails by seg faulting, unfortunately gdb is unable to
> print out a useful stack trace.


Do you have a listing of the x86 output? Then just debug as though it
was of piece of assembly code.


The correctness of individual instructions does not stop you having a
memory fault which can be due to incorrect contents of registers or
memory.


So look carefully at data allocations too. And double-check a
disassembly of your code to see if that's what you had in mind. Are
you sure your debugger can't tell which instruction it's failing on?


--
Bart

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