On 2013/4/19 12:56 AM, Cary Coutant wrote: > On Thu, Apr 18, 2013 at 6:49 AM, Chung-Lin Tang <clt...@codesourcery.com> > wrote: >> This patch was a fix by Julian which corrected a HOST_BITS_PER_WIDE_INT >> host dependency in dwarf generation. Nios II does not have >> need_64bit_hwint switched on during configuring, and ran into GDB test >> FAILs originating from this problem. >> >> 2013-04-18 Julian Brown <jul...@codesourcery.com> >> >> * dwarf2out.c (gen_enumeration_type_die): Fix >> HOST_BITS_PER_WIDE_INT dependency behavior in enumeration type >> DIE generation. > > + if (host_integerp (value, TYPE_UNSIGNED (TREE_TYPE (value))) > + && (simple_type_size_in_bits (TREE_TYPE (value)) > + <= HOST_BITS_PER_WIDE_INT || host_integerp (value, 0))) > /* DWARF2 does not provide a way of indicating whether or > not enumeration constants are signed or unsigned. GDB > always assumes the values are signed, so we output all > values as if they were signed. That means that > enumeration constants with very large unsigned values > will appear to have negative values in the debugger. */ > + add_AT_int (enum_die, DW_AT_const_value, TREE_INT_CST_LOW (value)); > + else > + /* Enumeration constants may be wider than HOST_WIDE_INT. Handle > + that here. */ > + add_AT_double (enum_die, DW_AT_const_value, > + TREE_INT_CST_HIGH (value), TREE_INT_CST_LOW (value)); > > I'm not sure I understand the logic here. I'd think either the value > fits in a signed HOST_WIDE_INT, and we use add_AT_int, or it doesn't, > and we use add_AT_double: > > if (host_integerp (value, 0)) > add_AT_int (enum_die, DW_AT_const_value, TREE_INT_CST_LOW (value)); > else > add_AT_double (enum_die, DW_AT_const_value, > TREE_INT_CST_HIGH (value), TREE_INT_CST_LOW (value)); > > Why wouldn't that work? I'd think this would even eliminate the need > for the comment about signed vs. unsigned. > > -cary
I think Julian might be able to fill clearer, but IIUC, if you use host_integer(value,0) as the test, while functionally also correct, for values like: TREE_INT_CST_HIGH (value) == 00000000... TREE_INT_CST_LOW (value) == 1xxxxxxx... you will end up placing it as a double, even if TREE_TYPE (value) is something within 32-bits, which you can actually place as an 'int'. In other words, the more complex condition saves a bit of dwarf size. Julian, can you comment further? Thanks, Chung-Lin
