On Mon, Apr 14, 2014 at 9:44 AM, Eric Botcazou <ebotca...@adacore.com> wrote: > Hi, > > in Ada types can be very dynamic: not only can their shape depend on variables > but it can also depend on the object itself (these are called self-referential > types). This raises interesting compile-time issues when you have dozens of > dynamic fields in a record type, or dozens of nested dynamic record types, as > every offset or size calculation is a fully-fledged expression in the GENERIC > language and they can quickly add up if you are not careful. > > This is dealt with in stor-layout.c by means of the variable_size function, > which ensures that these expressions are evaluated only once instead of being > duplicated again and again as the complexity grows up. The problem is that it > is only called for size expressions (DECL_SIZE and DECL_SIZE_UNIT), which is > fine for nested types, but not for offsets, which means that you will have a > memory explosion for flat types with dozens of consecutive dynamic fields. > > The patch plugs the hole by invoking it for DECL_FIELD_OFFSET as well (and the > effect is spectacular for pathological cases). Tested on x86_64-suse-linux, > although this will essentially only affect Ada. OK for the mainline?
Ok. Thanks, Richard. > > 2014-04-14 Eric Botcazou <ebotca...@adacore.com> > > * stor-layout.c (place_field): Finalize non-constant offset for the > field, if any. > > > -- > Eric Botcazou
