[RFA]: Fix for do_mixed_source_and_assembly in disasm.c

J. Johnston jjohnstn@redhat.com
Thu Dec 18 23:07:00 GMT 2003


Jason Molenda wrote:
> Hi Jeff,
> 
> On Dec 17, 2003, at 1:15 PM, Jeff Johnston wrote:
> 
>> There are a few bugs in do_mixed_source_and_assembly() when dealing 
>> with the ia64.
> 
> 
> I hit one of the two bugs you're fixing last week, namely the double 
> call to close off the list/tuple.  My first fix looked like yours, but I 
> think a slight reworking of the loop is very desirable here.  Right now 
> this loop looks approximately like this:
> 
> 
>    Set close_list to 1 (the list/tuple will be closed at the end of this 
> loop)
> 
>    First entry of a new source line number:
>      Start a "src_and_asm_line" tuple, print the source line.
>      Start a "line_asm_insn" list where instructions will be emitted.
>      If we're not at the end of the mle array, and the next mle entry's 
> source line number is not greater than the current source line entry, 
> DON'T close off the list (close_list = 0)
> 
>    Print the assembly instructions for the current address range.
> 
>    If close_list is 1, close the tuple/list.
> 
> 
> Which is a very convoluted way of writing a loop, and more importantly, 
> this only works correctly for one or two assembly ranges for a single 
> source line.  If you have a third, on the 2nd iter the tuple/list are 
> closed and then on the 3rd you close them again.
> 
> Instead, this is more clear:
> 
> 
>   First entry of a new source line number:
>      Start a "src_and_asm_line" tuple, print the source line.
>      Start a "line_asm_insn" list where instructions will be emitted.
> 
>   Print the assembly instructions for the current address range.
> 
>   If we're at the end of the mle array or the next entry in the array is 
> a new source line, close off the list and tuple.
> 
> 
> I also took the opportunity to combine two conditional statements - I 
> won't push hard for that part of the change, but the rest is a clear 
> improvement IMHO.
> 
> We only had this code path executed when we were using a compiler with a 
> bug in it internally, so it's not too easy for me to reproduce/test 
> this.  I've tried to combine my patch and yours against the current FSF 
> TOT.  What do you think of my suggested additional change?  Can you try 
> it on the IA64 test case you have?
> 
> 
> Jason
> 

Works fine.  I like the revision you made.  I don't know if the powers-that-be 
will review this patch before the New Year.

-- Jeff J.



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