Re: [PATCH v3 2/5] GDB: Fix the mess with value byte/bit range types

[Tom Tromey <tom@tromey.com>]

>>>>> "Maciej" == Maciej W Rozycki <macro@embecosm.com> writes:

Maciej> Consistently use the LONGEST and ULONGEST types for value byte/bit 
Maciej> offsets and lengths respectively, avoiding slient truncation for ranges 
Maciej> exceeding the 32-bit span, which may cause incorrect matching.  Also 
Maciej> report a conversion overflow on byte ranges that cannot be expressed in 
Maciej> terms of bits with these data types, e.g.:

Maciej>   (gdb) print one_hundred[1LL << 58]
Maciej>   Integer overflow in data location calculation
Maciej>   (gdb) print one_hundred[(-1LL << 58) - 1]
Maciej>   Integer overflow in data location calculation
Maciej>   (gdb)

Maciej> Previously such accesses would be let through with unpredictable results 
Maciej> produced.

Thank you.  I'm curious how you found the spots to change.

Maciej> +  if (offset != ((offset & mask) ^ sign) - sign
Maciej> +      || length != ((length & mask) ^ sign) - sign
Maciej> +      || (length > 0 && (~offset & (offset + length - 1) & sign) != 0))
Maciej> +    error (_("Integer overflow in data location calculation"));

Terrifying.  And to my surprise we don't seem to have any sort of
generic sign extension macro.

This patch is ok.

Tom