On 3/19/19 12:42 PM, Jeff Law wrote:
On 3/14/19 7:47 PM, Martin Sebor wrote:
To copy type attributes from struct A, the copy attribute (new
in GCC 9) accepts a pointer argument such as (struct A*)0, but
it isn't prepared for anything much more complicated than that.
So for example when it's passed something like (struct A*)(0, 1)
as the test case in PR 89685 does (a P1 regression), it fails
with an ICE.
The attached patch makes this handling more robust by letting
it accept all forms of type and member references.
Tested on x86_64-linux.
Martin
gcc-89685.diff
PR c/89685 - ICE on attribute copy with a compound expression
gcc/c-family/ChangeLog:
PR c/89685
* c-attribs.c (handle_copy_attribute): Handle references and
non-constant expressions.
gcc/testsuite/ChangeLog:
PR c/89685
* gcc.dg/attr-copy-8.c: New test.
* g++.dg/ext/attr-copy-2.C: New test.I think this is in the same state
as the __builtin_has_attribute bits --
you're trying to support attributes on expressions. We should reject
those as syntax errors right now.
There is no way for attribute copy to refer to a type but by
mentioning an expression:
struct __attribute__ ((aligned (8))) A { ... };
struct __attribute__ ((copy ((struct S*)0))) struct B { };
Copying type attributes is one third of the feature's documented
purpose:
copy
copy (expression)
The copy attribute applies the set of attributes with which
the type of the expression has been declared to the declaration
of the type to which the attribute is applied.
Why are you so determined to break these features?
Martin
