On Tue, Jun 28, 2022 at 06:15:58PM +0000, Qing Zhao wrote: > > Because the flag just tells whether some array shouldn't be treated as > > (poor man's) > > flexible array member. We still need to find out if some FIELD_DECL is to > > be treated like a flexible array member, which is a minority of > > COMPONENT_REFs. > > struct S { int a; char b[0]; int c; } s; > > struct T { int d; char e[]; }; > > struct U { int f; struct T g; int h; } u; > > Neither s.b nor u.g.e is to be treated like flexible array member, > > no matter what -fstrict-flex-array= option is used. > > Then, to resolve this issue, we might need a opposite flag DECL_IS_FLEXARRAY > in FIELD_DECL? > > The default is FALSE for all FIELD_DECL.
Doesn't matter whether it is positive or negative, you still need to analyze it. See the above example. If you have struct T t; and test t.e, then it is flexarray. But u.g.e is not, even when the COMPONENT_REF refers to the same FIELD_DECL. In the t.e case e is the very last field, in the latter case u.g.e is the last field in struct T, but struct U has the h field after it. Jakub