Query about the TREE_TYPE field

Andrew MacLeod amacleod@redhat.com
Tue Nov 18 14:40:00 GMT 2014

I was poking around attribs.c while trial running my tree-type-safety 
stuff, and it triggered something in decl_attributes() that seems fishy 
to me.  It looks like it was part of the fix for 

decl_attributes() can be passed a tree node which is either decl or a 
type, but we get to this little snippet:

       if (spec->type_required && DECL_P (*anode))
           anode = &TREE_TYPE (*anode);
           /* Allow ATTR_FLAG_TYPE_IN_PLACE for the type's naming decl.  */
           if (!(TREE_CODE (*anode) == TYPE_DECL
                 && *anode == TYPE_NAME (TYPE_MAIN_VARIANT
                                         (TREE_TYPE (*anode)))))
             flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;

anode is changed to point to the TREE_TYPE of the original decl, and 
*then* checks if it is a TYPE_DECL...   That doesnt seem right to me.. 
we can't have a TYPE_DECL as a TREE_TYPE can we?

is that code suppose to be checking is the original DECL is a TYPE_DECL 
rather than the TREE_TYPE?

I added an assert:
    anode = &TREE_TYPE (*anode);
+ gcc_assert (TREE_CODE (*anode) != TYPE_DECL);

and it never trips during bootstrap or a full testsuite run.  I also 
tried the testcase in bugzilla and it compiles fine with the assert in 

Maybe the assignment to anode should be after the if instead of in front 
of it?


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