On 9/1/23 09:04, Ben Boeckel wrote:
Hi,
This patch series adds initial support for ISO C++'s [P1689R5][], a
format for describing C++ module requirements and provisions based on
the source code. This is required because compiling C++ with modules is
not embarrassingly parallel and need to be ordered to ensure that
`import some_module;` can be satisfied in time by making sure that any
TU with `export import some_module;` is compiled first.
[P1689R5]: https://isocpp.org/files/papers/P1689R5.html
I've also added patches to include imported module CMI files and the
module mapper file as dependencies of the compilation. I briefly looked
into adding dependencies on response files as well, but that appeared to
need some code contortions to have a `class mkdeps` available before
parsing the command line or to keep the information around until one was
made.
I'd like feedback on the approach taken here with respect to the
user-visible flags. I'll also note that header units are not supported
at this time because the current `-E` behavior with respect to `import
<some_header>;` is to search for an appropriate `.gcm` file which is not
something such a "scan" can support. A new mode will likely need to be
created (e.g., replacing `-E` with `-fc++-module-scanning` or something)
where headers are looked up "normally" and processed only as much as
scanning requires.
FWIW, Clang as taken an alternate approach with its `clang-scan-deps`
tool rather than using the compiler directly.
Thanks,
--Ben
---
v7 -> v8:
- rename `DEPS_FMT_` enum variants to `FDEPS_FMT_` to match the
associated flag
- memory leak fix in the `join` specfunc implementation (also better
comments), both from Jason
- formatting fix in `mkdeps.cc` for `write_make_modules_deps` assignment
- comments on new functions for P1689R5 implementation
Pushed, thanks!
Jason
