On 3/6/24 21:12, Patrick Palka wrote:
On Wed, 6 Mar 2024, Jason Merrill wrote:
On 3/6/24 14:10, Patrick Palka wrote:
Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
-- >8 --
The unreduced testcase from this PR crashes at runtime ultimately
because we don't stream the abi_tag attribute on inline namespaces and
so the filesystem::current_path() call resolves to the non-C++11 ABI
version even though the C++11 ABI is active, leading to a crash when
destructing the call result (which contains an std::string member).
While we do stream the DECL_ATTRIBUTES of all decls that go through
the generic tree streaming routines, it seems namespaces are streamed
separately from other decls and we don't use the generic routines for
them. So this patch makes us stream the abi_tag manually for (inline)
namespaces.
Why not stream all DECL_ATTRIBUTES of all namespaces?
AFAICT abi_tag and deprecated are the only attributes that we recognize
on a namespace, and for deprecated it should suffice to stream the
TREE_DEPRECATED flag instead of the actual attribute, so hardcoding
abi_tag streaming seems convenient.
If we wanted to stream all DECL_ATTRIBUTES of a namespace then we'd have
to assume up front what kind of tree arguments of the attributes can be,
e.g. an INTEGER_CST or a STRING_CST etc and implement streaming of these
trees within the bytes_in/out base classes instead of trees_in/out (we
only have access to a bytes_in/out object from read/write_namespaces).
Hunh, why don't we use trees_in/out for namespaces?
But in that case, the patch is OK. You might use list_length (tags)
instead of writing the counting loop yourself. OK either way.
Jason
