------- Comment #12 from gary at intrepid dot com 2007-01-01 22:47 ------- Jim Wilson posted thi follow up to the GDB list: http://sourceware.org/ml/gdb/2007-01/msg00007.html
From: Jim Wilson <wilson at specifix dot com> Date: Mon, 01 Jan 2007 14:15:47 -0800 Subject: RE: how to support C type qualifiers applied to arrays? On Thu, 2006-12-14 at 12:22 -0800, Gary Funck wrote: > The main difficulty is that GCC doesn't create new qualified > types for declarations. Rather, it sets TREE_READONLY() > and TREE_THIS_VOLATILE() in the DECL node for declarations > such as: > volatile int A[10]; If you look at the types created by the C front end, they are OK. c_build_qualified_type knows how to handle an array correctly. The problem arises in the DWARF2 output code. gen_type_die calls type_main_variant for all types other than vector types, which strips off the const and volatile type modifiers. Then it clumsily tries to put them back later in gen_variable_die, except that for array types, it puts them back in the wrong place. This seems to answer the question I asked long ago. Why are we trying to put back qualifiers from the decl? Because gen_type_die stripped them off. This seems wrong. If we fix gen_type_die to stop calling type_main_variant, and if we fix gen_variable_die to stop adding back the type qualifiers, then I get the right result. So I think I was on the right track before, we just need another little change to gen_type_die in addition to what I already described. I haven't investigated this in detail yet. There may be other parts of the code that expect to see a type main variant here, so we might need other cascading fixes. This still seems fixable to me though. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=8354