[PATCH] dwarf2out: Represent bound_info with normal constant values if possible.

[Eric Botcazou]

> So the patch below makes it so that if HOST_WIDE_INT is wide enough then,
> depending on whether the range type is signed or not, add_AT_unsigned or
> add_AT_int is used. This is more efficient for small ranges. And makes it
> so that the value can be deduced from the DW_FORM by the consumer (which
> can assume again that DW_FORM_data[1248] are simply zero-extended and
> that negative constant values are represented by DW_FORM_sdata).

FWIW this looks an improvement to me.

> I tested this on x86_64 with --enable-languages=c,ada,c++,fortran,java,objc
> without regressions. I also made sure that the example ada program range
> is recognized correctly by gdb with this patch.
> 
> A couple of questions:
> 
> - Are there more ada DWARF tests? Something like guality used for c/fortran?

In the compiler proper no, but there is (of course) the GDB testsuite.

> - What values of HOST_BITS_PER_WIDE_INT are actually supported in GCC? The
> dwarf2out.c code tries to handle 8, 16, 32 and 64 bits for
>   dw_val_class_const_double.

32 and 64

> - Which setups use 32bit (or lower?) HOST_BITS_PER_WIDE_INT?
>   i686 seems to require 64BIT HOST_WIDE_INTs too these days.

Right, pure 32-bit hosted compilers are an endangered species and GNAT is 
probably not fully functional for these architectures.

How did you run into the problem?  Can't you conduct some minimal testing on 
64-bit platforms by using 128-bit integers (not in Ada unfortunately)?

-- 
Eric Botcazou