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* [PATCH v7 0/4] P1689R5 support
@ 2023-07-02 16:32 Ben Boeckel
  2023-07-02 16:32 ` [PATCH v7 1/4] spec: add a spec function to join arguments Ben Boeckel
                   ` (3 more replies)
  0 siblings, 4 replies; 8+ messages in thread
From: Ben Boeckel @ 2023-07-02 16:32 UTC (permalink / raw)
  To: gcc-patches; +Cc: Ben Boeckel, jason, nathan, fortran, gcc, brad.king

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

---
v6 -> v7:

- rebase onto `master` (80ae426a195 (d: Fix core.volatile.volatileLoad
  discarded if result is unused, 2023-07-02))
- add test cases for patches 3 and 4 (new dependency reporting in `-MF`)
- add a Python script to test aspects of generated dependency files
- a new `join` spec function to support `-fdeps-*` defaults based on the
  `-o` flag (needed to strip the leading space that appears otherwise)
- note that JSON writing support should be factored out for use by
  `libcpp` and `gcc` (libiberty?)
- use `.ddi` for the extension of `-fdeps-*` output files by default
- support defaults for `-fdeps-file=` and `-fdeps-target=` when only
  `-fdeps-format=` is provided (with tests)
- error if `-MF` and `-fdeps-file=` are both the same (non-`stdout`)
  file as their formats are incompatible
- expand the documentation on how the `-fdeps-*` flags should be used

v5 -> v6:

- rebase onto `master` (585c660f041 (reload1: Change return type of
  predicate function from int to bool, 2023-06-06))
- fix crash related to reporting imported CMI files as dependencies
- rework utf-8 validity to patch the new `cpp_valid_utf8_p` function
  instead of the core utf-8 decoding routine to reject invalid
  codepoints (preserves higher-level error detection of invalid utf-8)
- harmonize of `fdeps` spelling in flags, variables, comments, etc.
- rename `-fdeps-output=` to `-fdeps-target=`

v4 -> v5:

- add dependency tracking for imported modules to `-MF`
- add dependency tracking for static module mapper files given to
  `-fmodule-mapper=`

v3 -> v4:

- add missing spaces between function names and arguments

v2 -> v3:

- changelog entries moved to commit messages
- documentation updated/added in the UTF-8 routine editing

v1 -> v2:

- removal of the `deps_write(extra)` parameter to option-checking where
  ndeeded
- default parameter of `cpp_finish(fdeps_stream = NULL)`
- unification of libcpp UTF-8 validity functions from v1
- test cases for flag parsing states (depflags-*) and p1689 output
  (p1689-*)

Ben Boeckel (4):
  spec: add a spec function to join arguments
  p1689r5: initial support
  c++modules: report imported CMI files as dependencies
  c++modules: report module mapper files as a dependency

 gcc/c-family/c-opts.cc                        |  44 +++-
 gcc/c-family/c.opt                            |  12 +
 gcc/cp/mapper-client.cc                       |   5 +
 gcc/cp/mapper-client.h                        |   1 +
 gcc/cp/module.cc                              |  24 +-
 gcc/doc/invoke.texi                           |  27 +++
 gcc/gcc.cc                                    |  19 +-
 gcc/json.h                                    |   3 +
 gcc/testsuite/g++.dg/modules/depflags-f-MD.C  |   2 +
 gcc/testsuite/g++.dg/modules/depflags-f.C     |   3 +
 gcc/testsuite/g++.dg/modules/depflags-fi.C    |   4 +
 gcc/testsuite/g++.dg/modules/depflags-fj-MD.C |   3 +
 .../g++.dg/modules/depflags-fj-MF-share.C     |   6 +
 gcc/testsuite/g++.dg/modules/depflags-fj.C    |   4 +
 .../g++.dg/modules/depflags-fjo-MD.C          |   4 +
 gcc/testsuite/g++.dg/modules/depflags-fjo.C   |   5 +
 gcc/testsuite/g++.dg/modules/depflags-fo-MD.C |   3 +
 gcc/testsuite/g++.dg/modules/depflags-fo.C    |   4 +
 gcc/testsuite/g++.dg/modules/depflags-j-MD.C  |   2 +
 gcc/testsuite/g++.dg/modules/depflags-j.C     |   3 +
 gcc/testsuite/g++.dg/modules/depflags-jo-MD.C |   3 +
 gcc/testsuite/g++.dg/modules/depflags-jo.C    |   4 +
 gcc/testsuite/g++.dg/modules/depflags-o-MD.C  |   2 +
 gcc/testsuite/g++.dg/modules/depflags-o.C     |   3 +
 gcc/testsuite/g++.dg/modules/depreport-1_a.C  |  10 +
 gcc/testsuite/g++.dg/modules/depreport-1_b.C  |  12 +
 .../g++.dg/modules/depreport-2.modmap         |   2 +
 gcc/testsuite/g++.dg/modules/depreport-2_a.C  |  15 ++
 gcc/testsuite/g++.dg/modules/depreport-2_b.C  |  14 ++
 gcc/testsuite/g++.dg/modules/modules.exp      |   1 +
 gcc/testsuite/g++.dg/modules/p1689-1.C        |  17 ++
 gcc/testsuite/g++.dg/modules/p1689-1.exp.ddi  |  27 +++
 gcc/testsuite/g++.dg/modules/p1689-2.C        |  15 ++
 gcc/testsuite/g++.dg/modules/p1689-2.exp.ddi  |  16 ++
 gcc/testsuite/g++.dg/modules/p1689-3.C        |  13 +
 gcc/testsuite/g++.dg/modules/p1689-3.exp.ddi  |  16 ++
 gcc/testsuite/g++.dg/modules/p1689-4.C        |  13 +
 gcc/testsuite/g++.dg/modules/p1689-4.exp.ddi  |  14 ++
 gcc/testsuite/g++.dg/modules/p1689-5.C        |  13 +
 gcc/testsuite/g++.dg/modules/p1689-5.exp.ddi  |  14 ++
 .../g++.dg/modules/p1689-file-default.C       |  16 ++
 .../g++.dg/modules/p1689-file-default.exp.ddi |  27 +++
 .../g++.dg/modules/p1689-target-default.C     |  16 ++
 .../modules/p1689-target-default.exp.ddi      |  27 +++
 gcc/testsuite/g++.dg/modules/test-depfile.py  | 207 ++++++++++++++++
 gcc/testsuite/g++.dg/modules/test-p1689.py    | 222 ++++++++++++++++++
 gcc/testsuite/lib/modules.exp                 | 100 ++++++++
 libcpp/include/cpplib.h                       |  12 +-
 libcpp/include/mkdeps.h                       |   9 +-
 libcpp/init.cc                                |  13 +-
 libcpp/mkdeps.cc                              | 153 +++++++++++-
 51 files changed, 1181 insertions(+), 23 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-f-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-f.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fi.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fj-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fj-MF-share.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fj.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fjo-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fjo.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fo-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fo.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-j-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-j.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-jo-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-jo.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-o-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-o.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-1_a.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-1_b.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-2.modmap
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-2_a.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-2_b.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-1.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-1.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-2.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-2.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-3.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-3.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-4.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-4.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-5.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-5.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-file-default.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-file-default.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-target-default.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-target-default.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/test-depfile.py
 create mode 100644 gcc/testsuite/g++.dg/modules/test-p1689.py
 create mode 100644 gcc/testsuite/lib/modules.exp


base-commit: 80ae426a195a0d035640a6301da833564deade52
-- 
2.40.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH v7 1/4] spec: add a spec function to join arguments
  2023-07-02 16:32 [PATCH v7 0/4] P1689R5 support Ben Boeckel
@ 2023-07-02 16:32 ` Ben Boeckel
  2023-08-23 19:29   ` [PATCH v7 1/4] driver: " Jason Merrill
  2023-07-02 16:32 ` [PATCH v7 2/4] p1689r5: initial support Ben Boeckel
                   ` (2 subsequent siblings)
  3 siblings, 1 reply; 8+ messages in thread
From: Ben Boeckel @ 2023-07-02 16:32 UTC (permalink / raw)
  To: gcc-patches; +Cc: Ben Boeckel, jason, nathan, fortran, gcc, brad.king

When passing `-o` flags to other options, the typical `-o foo` spelling
leaves a leading whitespace when replacing elsewhere. This ends up
creating flags spelled as `-some-option-with-arg= foo.ext` which doesn't
parse properly. When attempting to make a spec function to just remove
the leading whitespace, the argument splitting ends up masking the
whitespace. However, the intended extension *also* ends up being its own
argument. To perform the desired behavior, the arguments need to be
concatenated together.

gcc/:

	* gcc.cc (join_spec_func): Add a spec function to join all
	arguments.

Signed-off-by: Ben Boeckel <ben.boeckel@kitware.com>
---
 gcc/gcc.cc | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index fdfac0b4fe4..44433b80d61 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -447,6 +447,7 @@ static const char *greater_than_spec_func (int, const char **);
 static const char *debug_level_greater_than_spec_func (int, const char **);
 static const char *dwarf_version_greater_than_spec_func (int, const char **);
 static const char *find_fortran_preinclude_file (int, const char **);
+static const char *join_spec_func (int, const char **);
 static char *convert_white_space (char *);
 static char *quote_spec (char *);
 static char *quote_spec_arg (char *);
@@ -1772,6 +1773,7 @@ static const struct spec_function static_spec_functions[] =
   { "debug-level-gt",		debug_level_greater_than_spec_func },
   { "dwarf-version-gt",		dwarf_version_greater_than_spec_func },
   { "fortran-preinclude-file",	find_fortran_preinclude_file},
+  { "join",			join_spec_func},
 #ifdef EXTRA_SPEC_FUNCTIONS
   EXTRA_SPEC_FUNCTIONS
 #endif
@@ -10975,6 +10977,19 @@ find_fortran_preinclude_file (int argc, const char **argv)
   return result;
 }
 
+/* The function takes any number of arguments and joins them together.  */
+
+static const char *
+join_spec_func (int argc, const char **argv)
+{
+  char *result = NULL;
+
+  for (int i = 0; i < argc; ++i)
+    result = reconcat(result, result ? result : "", argv[i], NULL);
+
+  return result;
+}
+
 /* If any character in ORIG fits QUOTE_P (_, P), reallocate the string
    so as to precede every one of them with a backslash.  Return the
    original string or the reallocated one.  */
-- 
2.40.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH v7 2/4] p1689r5: initial support
  2023-07-02 16:32 [PATCH v7 0/4] P1689R5 support Ben Boeckel
  2023-07-02 16:32 ` [PATCH v7 1/4] spec: add a spec function to join arguments Ben Boeckel
@ 2023-07-02 16:32 ` Ben Boeckel
  2023-08-23 19:37   ` Jason Merrill
  2023-07-02 16:32 ` [PATCH v7 3/4] c++modules: report imported CMI files as dependencies Ben Boeckel
  2023-07-02 16:32 ` [PATCH v7 4/4] c++modules: report module mapper files as a dependency Ben Boeckel
  3 siblings, 1 reply; 8+ messages in thread
From: Ben Boeckel @ 2023-07-02 16:32 UTC (permalink / raw)
  To: gcc-patches; +Cc: Ben Boeckel, jason, nathan, fortran, gcc, brad.king

This patch implements support for [P1689R5][] to communicate to a build
system the C++20 module dependencies to build systems so that they may
build `.gcm` files in the proper order.

Support is communicated through the following three new flags:

- `-fdeps-format=` specifies the format for the output. Currently named
  `p1689r5`.

- `-fdeps-file=` specifies the path to the file to write the format to.

- `-fdeps-target=` specifies the `.o` that will be written for the TU
  that is scanned. This is required so that the build system can
  correlate the dependency output with the actual compilation that will
  occur.

CMake supports this format as of 17 Jun 2022 (to be part of 3.25.0)
using an experimental feature selection (to allow for future usage
evolution without committing to how it works today). While it remains
experimental, docs may be found in CMake's documentation for
experimental features.

Future work may include using this format for Fortran module
dependencies as well, however this is still pending work.

[P1689R5]: https://isocpp.org/files/papers/P1689R5.html
[cmake-experimental]: https://gitlab.kitware.com/cmake/cmake/-/blob/master/Help/dev/experimental.rst

TODO:

- header-unit information fields

Header units (including the standard library headers) are 100%
unsupported right now because the `-E` mechanism wants to import their
BMIs. A new mode (i.e., something more workable than existing `-E`
behavior) that mocks up header units as if they were imported purely
from their path and content would be required.

- non-utf8 paths

The current standard says that paths that are not unambiguously
represented using UTF-8 are not supported (because these cases are rare
and the extra complication is not worth it at this time). Future
versions of the format might have ways of encoding non-UTF-8 paths. For
now, this patch just doesn't support non-UTF-8 paths (ignoring the
"unambiguously representable in UTF-8" case).

- figure out why junk gets placed at the end of the file

Sometimes it seems like the file gets a lot of `NUL` bytes appended to
it. It happens rarely and seems to be the result of some
`ftruncate`-style call which results in extra padding in the contents.
Noting it here as an observation at least.

libcpp/

	* include/cpplib.h: Add cpp_fdeps_format enum.
	(cpp_options): Add fdeps_format field
	(cpp_finish): Add structured dependency fdeps_stream parameter.
	* include/mkdeps.h (deps_add_module_target): Add flag for
	whether a module is exported or not.
	(fdeps_add_target): Add function.
	(deps_write_p1689r5): Add function.
	* init.cc (cpp_finish): Add new preprocessor parameter used for C++
	module tracking.
	* mkdeps.cc (mkdeps): Implement P1689R5 output.

gcc/

	* doc/invoke.texi: Document -fdeps-format=, -fdeps-file=, and
	-fdeps-target= flags.
	* gcc.cc: add defaults for -fdeps-target= and -fdeps-file= when
	only -fdeps-format= is specified.
	* json.h: Add a TODO item to refactor out to share with
	`libcpp/mkdeps.cc`.

gcc/c-family/

	* c-opts.cc (c_common_handle_option): Add fdeps_file variable and
	-fdeps-format=, -fdeps-file=, and -fdeps-target= parsing.
	* c.opt: Add -fdeps-format=, -fdeps-file=, and -fdeps-target=
	flags.

gcc/cp/

	* module.cc (preprocessed_module): Pass whether the module is
	exported to dependency tracking.

gcc/testsuite/

	* g++.dg/modules/depflags-f-MD.C: New test.
	* g++.dg/modules/depflags-f.C: New test.
	* g++.dg/modules/depflags-fi.C: New test.
	* g++.dg/modules/depflags-fj-MD.C: New test.
	* g++.dg/modules/depflags-fj.C: New test.
	* g++.dg/modules/depflags-fjo-MD.C: New test.
	* g++.dg/modules/depflags-fjo.C: New test.
	* g++.dg/modules/depflags-fo-MD.C: New test.
	* g++.dg/modules/depflags-fo.C: New test.
	* g++.dg/modules/depflags-j-MD.C: New test.
	* g++.dg/modules/depflags-j.C: New test.
	* g++.dg/modules/depflags-jo-MD.C: New test.
	* g++.dg/modules/depflags-jo.C: New test.
	* g++.dg/modules/depflags-o-MD.C: New test.
	* g++.dg/modules/depflags-o.C: New test.
	* g++.dg/modules/p1689-1.C: New test.
	* g++.dg/modules/p1689-1.exp.ddi: New test expectation.
	* g++.dg/modules/p1689-2.C: New test.
	* g++.dg/modules/p1689-2.exp.ddi: New test expectation.
	* g++.dg/modules/p1689-3.C: New test.
	* g++.dg/modules/p1689-3.exp.ddi: New test expectation.
	* g++.dg/modules/p1689-4.C: New test.
	* g++.dg/modules/p1689-4.exp.ddi: New test expectation.
	* g++.dg/modules/p1689-5.C: New test.
	* g++.dg/modules/p1689-5.exp.ddi: New test expectation.
	* g++.dg/modules/modules.exp: Load new P1689 library routines.
	* g++.dg/modules/test-p1689.py: New tool for validating P1689 output.
	* lib/modules.exp: Support for validating P1689 outputs.

Signed-off-by: Ben Boeckel <ben.boeckel@kitware.com>
---
 gcc/c-family/c-opts.cc                        |  44 +++-
 gcc/c-family/c.opt                            |  12 +
 gcc/cp/module.cc                              |   3 +-
 gcc/doc/invoke.texi                           |  27 +++
 gcc/gcc.cc                                    |   4 +-
 gcc/json.h                                    |   3 +
 gcc/testsuite/g++.dg/modules/depflags-f-MD.C  |   2 +
 gcc/testsuite/g++.dg/modules/depflags-f.C     |   3 +
 gcc/testsuite/g++.dg/modules/depflags-fi.C    |   4 +
 gcc/testsuite/g++.dg/modules/depflags-fj-MD.C |   3 +
 .../g++.dg/modules/depflags-fj-MF-share.C     |   6 +
 gcc/testsuite/g++.dg/modules/depflags-fj.C    |   4 +
 .../g++.dg/modules/depflags-fjo-MD.C          |   4 +
 gcc/testsuite/g++.dg/modules/depflags-fjo.C   |   5 +
 gcc/testsuite/g++.dg/modules/depflags-fo-MD.C |   3 +
 gcc/testsuite/g++.dg/modules/depflags-fo.C    |   4 +
 gcc/testsuite/g++.dg/modules/depflags-j-MD.C  |   2 +
 gcc/testsuite/g++.dg/modules/depflags-j.C     |   3 +
 gcc/testsuite/g++.dg/modules/depflags-jo-MD.C |   3 +
 gcc/testsuite/g++.dg/modules/depflags-jo.C    |   4 +
 gcc/testsuite/g++.dg/modules/depflags-o-MD.C  |   2 +
 gcc/testsuite/g++.dg/modules/depflags-o.C     |   3 +
 gcc/testsuite/g++.dg/modules/modules.exp      |   1 +
 gcc/testsuite/g++.dg/modules/p1689-1.C        |  17 ++
 gcc/testsuite/g++.dg/modules/p1689-1.exp.ddi  |  27 +++
 gcc/testsuite/g++.dg/modules/p1689-2.C        |  15 ++
 gcc/testsuite/g++.dg/modules/p1689-2.exp.ddi  |  16 ++
 gcc/testsuite/g++.dg/modules/p1689-3.C        |  13 +
 gcc/testsuite/g++.dg/modules/p1689-3.exp.ddi  |  16 ++
 gcc/testsuite/g++.dg/modules/p1689-4.C        |  13 +
 gcc/testsuite/g++.dg/modules/p1689-4.exp.ddi  |  14 ++
 gcc/testsuite/g++.dg/modules/p1689-5.C        |  13 +
 gcc/testsuite/g++.dg/modules/p1689-5.exp.ddi  |  14 ++
 .../g++.dg/modules/p1689-file-default.C       |  16 ++
 .../g++.dg/modules/p1689-file-default.exp.ddi |  27 +++
 .../g++.dg/modules/p1689-target-default.C     |  16 ++
 .../modules/p1689-target-default.exp.ddi      |  27 +++
 gcc/testsuite/g++.dg/modules/test-p1689.py    | 222 ++++++++++++++++++
 gcc/testsuite/lib/modules.exp                 |  71 ++++++
 libcpp/include/cpplib.h                       |  12 +-
 libcpp/include/mkdeps.h                       |   9 +-
 libcpp/init.cc                                |  13 +-
 libcpp/mkdeps.cc                              | 153 +++++++++++-
 43 files changed, 859 insertions(+), 14 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-f-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-f.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fi.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fj-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fj-MF-share.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fj.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fjo-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fjo.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fo-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-fo.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-j-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-j.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-jo-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-jo.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-o-MD.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depflags-o.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-1.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-1.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-2.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-2.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-3.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-3.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-4.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-4.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-5.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-5.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-file-default.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-file-default.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-target-default.C
 create mode 100644 gcc/testsuite/g++.dg/modules/p1689-target-default.exp.ddi
 create mode 100644 gcc/testsuite/g++.dg/modules/test-p1689.py
 create mode 100644 gcc/testsuite/lib/modules.exp

diff --git a/gcc/c-family/c-opts.cc b/gcc/c-family/c-opts.cc
index af19140e382..9d794b2f4de 100644
--- a/gcc/c-family/c-opts.cc
+++ b/gcc/c-family/c-opts.cc
@@ -77,6 +77,9 @@ static bool verbose;
 /* Dependency output file.  */
 static const char *deps_file;
 
+/* Structured dependency output file.  */
+static const char *fdeps_file;
+
 /* The prefix given by -iprefix, if any.  */
 static const char *iprefix;
 
@@ -361,6 +364,24 @@ c_common_handle_option (size_t scode, const char *arg, HOST_WIDE_INT value,
       deps_file = arg;
       break;
 
+    case OPT_fdeps_format_:
+      /* https://wg21.link/p1689r5 */
+      if (!strcmp (arg, "p1689r5"))
+	cpp_opts->deps.fdeps_format = DEPS_FMT_P1689R5;
+      else
+	error ("%<-fdeps-format=%> unknown format %<%s%>", arg);
+      break;
+
+    case OPT_fdeps_file_:
+      deps_seen = true;
+      fdeps_file = arg;
+      break;
+
+    case OPT_fdeps_target_:
+      deps_seen = true;
+      defer_opt (code, arg);
+      break;
+
     case OPT_MF:
       deps_seen = true;
       deps_file = arg;
@@ -1280,6 +1301,7 @@ void
 c_common_finish (void)
 {
   FILE *deps_stream = NULL;
+  FILE *fdeps_stream = NULL;
 
   /* Note that we write the dependencies even if there are errors. This is
      useful for handling outdated generated headers that now trigger errors
@@ -1308,9 +1330,27 @@ c_common_finish (void)
      locations with input_location, which would be incorrect now.  */
   override_libcpp_locations = false;
 
+  if (cpp_opts->deps.fdeps_format != DEPS_FMT_NONE)
+    {
+      if (!fdeps_file)
+	fdeps_stream = out_stream;
+      else if (fdeps_file[0] == '-' && fdeps_file[1] == '\0')
+	fdeps_stream = stdout;
+      else
+	{
+	  fdeps_stream = fopen (fdeps_file, "w");
+	  if (!fdeps_stream)
+	    fatal_error (input_location, "opening dependency file %s: %m",
+			 fdeps_file);
+	}
+      if (fdeps_stream == deps_stream && fdeps_stream != stdout)
+	fatal_error (input_location, "%<-MF%> and %<-fdeps-file=%> cannot share an output file %s: %m",
+		     fdeps_file);
+    }
+
   /* For performance, avoid tearing down cpplib's internal structures
      with cpp_destroy ().  */
-  cpp_finish (parse_in, deps_stream);
+  cpp_finish (parse_in, deps_stream, fdeps_stream);
 
   if (deps_stream && deps_stream != out_stream && deps_stream != stdout
       && (ferror (deps_stream) || fclose (deps_stream)))
@@ -1382,6 +1422,8 @@ handle_deferred_opts (void)
 
 	if (opt->code == OPT_MT || opt->code == OPT_MQ)
 	  deps_add_target (deps, opt->arg, opt->code == OPT_MQ);
+	else if (opt->code == OPT_fdeps_target_)
+	  fdeps_add_target (deps, opt->arg, true);
       }
 }
 
diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 4abdc8d0e77..4781ca831d6 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -256,6 +256,18 @@ MT
 C ObjC C++ ObjC++ Joined Separate MissingArgError(missing makefile target after %qs)
 -MT <target>	Add a target that does not require quoting.
 
+fdeps-format=
+C ObjC C++ ObjC++ NoDriverArg Joined MissingArgError(missing format after %qs)
+Structured format for output dependency information.  Supported (\"p1689r5\").
+
+fdeps-file=
+C ObjC C++ ObjC++ NoDriverArg Joined MissingArgError(missing output path after %qs)
+File for output dependency information.
+
+fdeps-target=
+C ObjC C++ ObjC++ NoDriverArg Joined MissingArgError(missing path after %qs)
+-fdeps-target=obj.o Output file for the compile step.
+
 P
 C ObjC C++ ObjC++
 Do not generate #line directives.
diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index ea362bdffa4..9df60d695b1 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -19834,7 +19834,8 @@ preprocessed_module (cpp_reader *reader)
 		  && (module->is_interface () || module->is_partition ()))
 		deps_add_module_target (deps, module->get_flatname (),
 					maybe_add_cmi_prefix (module->filename),
-					module->is_header());
+					module->is_header (),
+					module->is_exported ());
 	      else
 		deps_add_module_dep (deps, module->get_flatname ());
 	    }
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index efcf3bfb3d6..d3582049582 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -2820,6 +2820,33 @@ is @option{-fpermitted-flt-eval-methods=c11}.  The default when in a GNU
 dialect (@option{-std=gnu11} or similar) is
 @option{-fpermitted-flt-eval-methods=ts-18661-3}.
 
+@opindex fdeps-
+The @samp{-fdeps-*} options are used to extract structured dependency
+information for a source.  This involves determining what resources provided by
+other source files will be required to compile the source as well as what
+resources are provided by the source.  This information can be used to add
+required dependencies between compilation rules of dependent sources based on
+their contents rather than requiring such information be reflected within the
+build tools as well.
+
+@opindex fdeps-file
+@item -fdeps-file=@var{file}
+Where to write structured dependency information.
+
+@opindex fdeps-format
+@item -fdeps-format=@var{format}
+The format to use for structured dependency information. @samp{p1689r5} is the
+only supported format right now.  Note that when this argument is specified, the
+output of @samp{-MF} is stripped of some information (namely C++ modules) so
+that it does not use extended makefile syntax not understood by most tools.
+
+@opindex fdeps-target
+@item -fdeps-target=@var{file}
+Analogous to @option{-MT} but for structured dependency information.  This
+indicates the target which will ultimately need any required resources and
+provide any resources extracted from the source that may be required by other
+sources.
+
 @opindex fplan9-extensions
 @item -fplan9-extensions
 Accept some non-standard constructs used in Plan 9 code.
diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index 44433b80d61..0a9818374f0 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -1236,7 +1236,9 @@ static const char *cpp_unique_options =
  %{remap} %{%:debug-level-gt(2):-dD}\
  %{!iplugindir*:%{fplugin*:%:find-plugindir()}}\
  %{H} %C %{D*&U*&A*} %{i*} %Z %i\
- %{E|M|MM:%W{o*}}";
+ %{E|M|MM:%W{o*}}\
+ %{fdeps-format=*:%{!fdeps-file=*:-fdeps-file=%:join(%{!o:%b.ddi}%{o*:%.ddi%*})}}\
+ %{fdeps-format=*:%{!fdeps-target=*:-fdeps-target=%:join(%{!o:%b.o}%{o*:%.o%*})}}";
 
 /* This contains cpp options which are common with cc1_options and are passed
    only when preprocessing only to avoid duplication.  We pass the cc1 spec
diff --git a/gcc/json.h b/gcc/json.h
index 057119db277..6cc58c8ae0c 100644
--- a/gcc/json.h
+++ b/gcc/json.h
@@ -30,6 +30,9 @@ along with GCC; see the file COPYING3.  If not see
    Supports creating a DOM-like tree of json::value *, and then dumping
    json::value * to text.  */
 
+/* TODO: `libcpp/mkdeps.cc` wants JSON writing support for p1689r5 output;
+   extract this code and move to libiberty.  */
+
 namespace json
 {
 
diff --git a/gcc/testsuite/g++.dg/modules/depflags-f-MD.C b/gcc/testsuite/g++.dg/modules/depflags-f-MD.C
new file mode 100644
index 00000000000..2bd980c0047
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-f-MD.C
@@ -0,0 +1,2 @@
+// { dg-additional-options -MD }
+// { dg-additional-options -fdeps-format=p1689r5 }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-f.C b/gcc/testsuite/g++.dg/modules/depflags-f.C
new file mode 100644
index 00000000000..789b18f59e4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-f.C
@@ -0,0 +1,3 @@
+// { dg-additional-options -fdeps-format=p1689r5 }
+
+// { dg-prune-output "error: to generate dependencies you must specify either '-M' or '-MM'" }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-fi.C b/gcc/testsuite/g++.dg/modules/depflags-fi.C
new file mode 100644
index 00000000000..d8e75ad9089
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-fi.C
@@ -0,0 +1,4 @@
+// { dg-additional-options -fdeps-format=invalid }
+
+// { dg-prune-output "error: '-fdeps-format=' unknown format 'invalid'"  }
+// { dg-prune-output "error: to generate dependencies you must specify either '-M' or '-MM'" }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-fj-MD.C b/gcc/testsuite/g++.dg/modules/depflags-fj-MD.C
new file mode 100644
index 00000000000..3a9452345a8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-fj-MD.C
@@ -0,0 +1,3 @@
+// { dg-additional-options -MD }
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
+// { dg-additional-options -fdeps-format=p1689r5 }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-fj-MF-share.C b/gcc/testsuite/g++.dg/modules/depflags-fj-MF-share.C
new file mode 100644
index 00000000000..723014f7a0e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-fj-MF-share.C
@@ -0,0 +1,6 @@
+// { dg-additional-options -MD }
+// { dg-additional-options "-MF depflags-3.ddi" }
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
+// { dg-additional-options -fdeps-format=p1689r5 }
+
+// { dg-prune-output "error: '-MF' and '-fdeps-file=' cannot share an output file" }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-fj.C b/gcc/testsuite/g++.dg/modules/depflags-fj.C
new file mode 100644
index 00000000000..063e0ee5514
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-fj.C
@@ -0,0 +1,4 @@
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
+// { dg-additional-options -fdeps-format=p1689r5 }
+
+// { dg-prune-output "error: to generate dependencies you must specify either '-M' or '-MM'" }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-fjo-MD.C b/gcc/testsuite/g++.dg/modules/depflags-fjo-MD.C
new file mode 100644
index 00000000000..84da337f9f6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-fjo-MD.C
@@ -0,0 +1,4 @@
+// { dg-additional-options -MD }
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
+// { dg-additional-options -fdeps-target=depflags-1.C }
+// { dg-additional-options -fdeps-format=p1689r5 }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-fjo.C b/gcc/testsuite/g++.dg/modules/depflags-fjo.C
new file mode 100644
index 00000000000..760d8f26f66
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-fjo.C
@@ -0,0 +1,5 @@
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
+// { dg-additional-options -fdeps-target=depflags-1.C }
+// { dg-additional-options -fdeps-format=p1689r5 }
+
+// { dg-prune-output "error: to generate dependencies you must specify either '-M' or '-MM'" }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-fo-MD.C b/gcc/testsuite/g++.dg/modules/depflags-fo-MD.C
new file mode 100644
index 00000000000..6da03f9133f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-fo-MD.C
@@ -0,0 +1,3 @@
+// { dg-additional-options -MD }
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-target=depflags-1.C }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-fo.C b/gcc/testsuite/g++.dg/modules/depflags-fo.C
new file mode 100644
index 00000000000..5deb27a4598
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-fo.C
@@ -0,0 +1,4 @@
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-target=depflags-1.C }
+
+// { dg-prune-output "error: to generate dependencies you must specify either '-M' or '-MM'" }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-j-MD.C b/gcc/testsuite/g++.dg/modules/depflags-j-MD.C
new file mode 100644
index 00000000000..92a2af61e78
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-j-MD.C
@@ -0,0 +1,2 @@
+// { dg-additional-options -MD }
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-j.C b/gcc/testsuite/g++.dg/modules/depflags-j.C
new file mode 100644
index 00000000000..2eb5890938e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-j.C
@@ -0,0 +1,3 @@
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
+
+// { dg-prune-output "error: to generate dependencies you must specify either '-M' or '-MM'" }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-jo-MD.C b/gcc/testsuite/g++.dg/modules/depflags-jo-MD.C
new file mode 100644
index 00000000000..ba2b21e3066
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-jo-MD.C
@@ -0,0 +1,3 @@
+// { dg-additional-options -MD }
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
+// { dg-additional-options -fdeps-target=depflags-1.C }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-jo.C b/gcc/testsuite/g++.dg/modules/depflags-jo.C
new file mode 100644
index 00000000000..a015d35141f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-jo.C
@@ -0,0 +1,4 @@
+// { dg-additional-options -fdeps-file=depflags-3.ddi }
+// { dg-additional-options -fdeps-target=depflags-1.C }
+
+// { dg-prune-output "error: to generate dependencies you must specify either '-M' or '-MM'" }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-o-MD.C b/gcc/testsuite/g++.dg/modules/depflags-o-MD.C
new file mode 100644
index 00000000000..1b67558b687
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-o-MD.C
@@ -0,0 +1,2 @@
+// { dg-additional-options -MD }
+// { dg-additional-options -fdeps-target=depflags-1.C }
diff --git a/gcc/testsuite/g++.dg/modules/depflags-o.C b/gcc/testsuite/g++.dg/modules/depflags-o.C
new file mode 100644
index 00000000000..38d645081b6
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depflags-o.C
@@ -0,0 +1,3 @@
+// { dg-additional-options -fdeps-target=depflags-1.C }
+
+// { dg-prune-output "error: to generate dependencies you must specify either '-M' or '-MM'" }
diff --git a/gcc/testsuite/g++.dg/modules/modules.exp b/gcc/testsuite/g++.dg/modules/modules.exp
index dc302d3d0af..b6929544c59 100644
--- a/gcc/testsuite/g++.dg/modules/modules.exp
+++ b/gcc/testsuite/g++.dg/modules/modules.exp
@@ -28,6 +28,7 @@
 # { dg-module-do [link|run] [xfail] [options] } # link [and run]
 
 load_lib g++-dg.exp
+load_lib modules.exp
 
 # If a testcase doesn't have special options, use these.
 global DEFAULT_CXXFLAGS
diff --git a/gcc/testsuite/g++.dg/modules/p1689-1.C b/gcc/testsuite/g++.dg/modules/p1689-1.C
new file mode 100644
index 00000000000..3c138c8f82e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-1.C
@@ -0,0 +1,17 @@
+// { dg-additional-options -E }
+// { dg-additional-options "-MT p1689-1.ddi" }
+// { dg-additional-options -MD }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-target=p1689-1.o }
+// { dg-additional-options -fdeps-file=p1689-1.ddi }
+
+// Export a module that uses modules, re-exports modules, and partitions.
+
+export module foo;
+export import foo:part1;
+import foo:part2;
+
+export import bar;
+
+// { dg-final { run-check-p1689-valid p1689-1.ddi p1689-1.exp.ddi } }
diff --git a/gcc/testsuite/g++.dg/modules/p1689-1.exp.ddi b/gcc/testsuite/g++.dg/modules/p1689-1.exp.ddi
new file mode 100644
index 00000000000..c5648ac7ae5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-1.exp.ddi
@@ -0,0 +1,27 @@
+{
+    "rules": [
+        {
+            "primary-output": "p1689-1.o",
+            "provides": [
+                {
+                    "logical-name": "foo",
+                    "is-interface": true
+                }
+            ],
+            "requires": [
+                "__P1689_unordered__",
+                {
+                    "logical-name": "bar"
+                },
+                {
+                    "logical-name": "foo:part1"
+                },
+                {
+                    "logical-name": "foo:part2"
+                }
+            ]
+        }
+    ],
+    "version": 0,
+    "revision": 0
+}
diff --git a/gcc/testsuite/g++.dg/modules/p1689-2.C b/gcc/testsuite/g++.dg/modules/p1689-2.C
new file mode 100644
index 00000000000..5d7fe52a809
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-2.C
@@ -0,0 +1,15 @@
+// { dg-additional-options -E }
+// { dg-additional-options "-MT p1689-2.ddi" }
+// { dg-additional-options -MD }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-target=p1689-2.o }
+// { dg-additional-options -fdeps-file=p1689-2.ddi }
+
+// Export a module partition that uses modules.
+
+export module foo:part1;
+
+#include <iostream>
+
+// { dg-final { run-check-p1689-valid p1689-2.ddi p1689-2.exp.ddi } }
diff --git a/gcc/testsuite/g++.dg/modules/p1689-2.exp.ddi b/gcc/testsuite/g++.dg/modules/p1689-2.exp.ddi
new file mode 100644
index 00000000000..6901172f277
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-2.exp.ddi
@@ -0,0 +1,16 @@
+{
+    "rules": [
+        {
+            "primary-output": "p1689-2.o",
+            "provides": [
+                {
+                    "logical-name": "foo:part1",
+                    "is-interface": true
+                }
+            ],
+            "requires": []
+        }
+    ],
+    "version": 0,
+    "revision": 0
+}
diff --git a/gcc/testsuite/g++.dg/modules/p1689-3.C b/gcc/testsuite/g++.dg/modules/p1689-3.C
new file mode 100644
index 00000000000..6c0aced5419
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-3.C
@@ -0,0 +1,13 @@
+// { dg-additional-options -E }
+// { dg-additional-options "-MT p1689-3.ddi" }
+// { dg-additional-options -MD }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-target=p1689-3.o }
+// { dg-additional-options -fdeps-file=p1689-3.ddi }
+
+// Provide a module partition.
+
+module foo:part2;
+
+// { dg-final { run-check-p1689-valid p1689-3.ddi p1689-3.exp.ddi } }
diff --git a/gcc/testsuite/g++.dg/modules/p1689-3.exp.ddi b/gcc/testsuite/g++.dg/modules/p1689-3.exp.ddi
new file mode 100644
index 00000000000..5a40beacd22
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-3.exp.ddi
@@ -0,0 +1,16 @@
+{
+    "rules": [
+        {
+            "primary-output": "p1689-3.o",
+            "provides": [
+                {
+                    "logical-name": "foo:part2",
+                    "is-interface": false
+                }
+            ],
+            "requires": []
+        }
+    ],
+    "version": 0,
+    "revision": 0
+}
diff --git a/gcc/testsuite/g++.dg/modules/p1689-4.C b/gcc/testsuite/g++.dg/modules/p1689-4.C
new file mode 100644
index 00000000000..922f0158440
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-4.C
@@ -0,0 +1,13 @@
+// { dg-additional-options -E }
+// { dg-additional-options "-MT p1689-4.ddi" }
+// { dg-additional-options -MD }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-target=p1689-4.o }
+// { dg-additional-options -fdeps-file=p1689-4.ddi }
+
+// Module implementation unit.
+
+module foo;
+
+// { dg-final { run-check-p1689-valid p1689-4.ddi p1689-4.exp.ddi } }
diff --git a/gcc/testsuite/g++.dg/modules/p1689-4.exp.ddi b/gcc/testsuite/g++.dg/modules/p1689-4.exp.ddi
new file mode 100644
index 00000000000..b119f5654b1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-4.exp.ddi
@@ -0,0 +1,14 @@
+{
+    "rules": [
+        {
+            "primary-output": "p1689-4.o",
+            "requires": []
+                {
+                    "logical-name": "foo"
+                }
+            ]
+        }
+    ],
+    "version": 0,
+    "revision": 0
+}
diff --git a/gcc/testsuite/g++.dg/modules/p1689-5.C b/gcc/testsuite/g++.dg/modules/p1689-5.C
new file mode 100644
index 00000000000..94908bf8a03
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-5.C
@@ -0,0 +1,13 @@
+// { dg-additional-options -E }
+// { dg-additional-options "-MT p1689-5.ddi" }
+// { dg-additional-options -MD }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-target=p1689-5.o }
+// { dg-additional-options -fdeps-file=p1689-5.ddi }
+
+// Use modules, don't provide anything.
+
+import bar;
+
+// { dg-final { run-check-p1689-valid p1689-5.ddi p1689-5.exp.ddi } }
diff --git a/gcc/testsuite/g++.dg/modules/p1689-5.exp.ddi b/gcc/testsuite/g++.dg/modules/p1689-5.exp.ddi
new file mode 100644
index 00000000000..18704ac8820
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-5.exp.ddi
@@ -0,0 +1,14 @@
+{
+    "rules": [
+        {
+            "primary-output": "p1689-5.o",
+            "requires": [
+                {
+                    "logical-name": "bar"
+                }
+            ]
+        }
+    ],
+    "version": 0,
+    "revision": 0
+}
diff --git a/gcc/testsuite/g++.dg/modules/p1689-file-default.C b/gcc/testsuite/g++.dg/modules/p1689-file-default.C
new file mode 100644
index 00000000000..4e1f5bbd2f7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-file-default.C
@@ -0,0 +1,16 @@
+// { dg-additional-options -E }
+// { dg-additional-options "-MT p1689-file-default.ddi" }
+// { dg-additional-options -MD }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-target=p1689-file-default.o }
+
+// Scan without `-fdeps-file=`
+
+export module foo;
+export import foo:part1;
+import foo:part2;
+
+export import bar;
+
+// { dg-final { run-check-p1689-valid p1689-file-default.o.ddi p1689-file-default.exp.ddi } }
diff --git a/gcc/testsuite/g++.dg/modules/p1689-file-default.exp.ddi b/gcc/testsuite/g++.dg/modules/p1689-file-default.exp.ddi
new file mode 100644
index 00000000000..187eab6141a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-file-default.exp.ddi
@@ -0,0 +1,27 @@
+{
+    "rules": [
+        {
+            "primary-output": "p1689-file-default.o",
+            "provides": [
+                {
+                    "logical-name": "foo",
+                    "is-interface": true
+                }
+            ],
+            "requires": [
+                "__P1689_unordered__",
+                {
+                    "logical-name": "bar"
+                },
+                {
+                    "logical-name": "foo:part1"
+                },
+                {
+                    "logical-name": "foo:part2"
+                }
+            ]
+        }
+    ],
+    "version": 0,
+    "revision": 0
+}
diff --git a/gcc/testsuite/g++.dg/modules/p1689-target-default.C b/gcc/testsuite/g++.dg/modules/p1689-target-default.C
new file mode 100644
index 00000000000..67088ed2769
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-target-default.C
@@ -0,0 +1,16 @@
+// { dg-additional-options -E }
+// { dg-additional-options "-MT p1689-target-default.ddi" }
+// { dg-additional-options -MD }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fdeps-format=p1689r5 }
+// { dg-additional-options -fdeps-file=p1689-target-default.ddi }
+
+// Scan without `-fdeps-target=`
+
+export module foo;
+export import foo:part1;
+import foo:part2;
+
+export import bar;
+
+// { dg-final { run-check-p1689-valid p1689-target-default.ddi p1689-target-default.exp.ddi } }
diff --git a/gcc/testsuite/g++.dg/modules/p1689-target-default.exp.ddi b/gcc/testsuite/g++.dg/modules/p1689-target-default.exp.ddi
new file mode 100644
index 00000000000..dd3d9c44705
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/p1689-target-default.exp.ddi
@@ -0,0 +1,27 @@
+{
+    "rules": [
+        {
+            "primary-output": "p1689-target-default.o",
+            "provides": [
+                {
+                    "logical-name": "foo",
+                    "is-interface": true
+                }
+            ],
+            "requires": [
+                "__P1689_unordered__",
+                {
+                    "logical-name": "bar"
+                },
+                {
+                    "logical-name": "foo:part1"
+                },
+                {
+                    "logical-name": "foo:part2"
+                }
+            ]
+        }
+    ],
+    "version": 0,
+    "revision": 0
+}
diff --git a/gcc/testsuite/g++.dg/modules/test-p1689.py b/gcc/testsuite/g++.dg/modules/test-p1689.py
new file mode 100644
index 00000000000..2f07cc361aa
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/test-p1689.py
@@ -0,0 +1,222 @@
+import json
+
+
+# Parameters.
+ALL_ERRORS = False
+REPLACEMENTS = {}
+
+
+def _print_path(path):
+    '''Format a JSON path for output.'''
+    return '/'.join(path)
+
+
+def _report_error(msg):
+    '''Report an error.'''
+    full_msg = 'ERROR: ' + msg
+    if ALL_ERRORS:
+        print(full_msg)
+    else:
+        raise RuntimeError(full_msg)
+
+
+def _error_type_mismatch(path, actual, expect):
+    '''Report that there is a type mismatch.'''
+    _report_error('type mismatch at %s: actual: "%s" expect: "%s"' % (_print_path(path), actual, expect))
+
+
+def _error_unknown_type(path, typ):
+    '''Report that there is an unknown type in the JSON object.'''
+    _report_error('unknown type at %s: "%s"' % (_print_path(path), typ))
+
+
+def _error_length_mismatch(path, actual, expect):
+    '''Report a length mismatch in an object or array.'''
+    _report_error('length mismatch at %s: actual: "%s" expect: "%s"' % (_print_path(path), actual, expect))
+
+
+def _error_unexpect_value(path, actual, expect):
+    '''Report a value mismatch.'''
+    _report_error('value mismatch at %s: actual: "%s" expect: "%s"' % (_print_path(path), actual, expect))
+
+
+def _error_extra_key(path, key):
+    '''Report on a key that is unexpected.'''
+    _report_error('extra key at %s: "%s"' % (_print_path(path), key))
+
+
+def _error_missing_key(path, key):
+    '''Report on a key that is missing.'''
+    _report_error('extra key at %s: %s' % (_print_path(path), key))
+
+
+def _compare_object(path, actual, expect):
+    '''Compare a JSON object.'''
+    is_ok = True
+
+    if not len(actual) == len(expect):
+        _error_length_mismatch(path, len(actual), len(expect))
+        is_ok = False
+
+    for key in actual:
+        if key not in expect:
+            _error_extra_key(path, key)
+            is_ok = False
+        else:
+            sub_error = compare_json(path + [key], actual[key], expect[key])
+            if sub_error:
+                is_ok = False
+
+    for key in expect:
+        if key not in actual:
+            _error_missing_key(path, key)
+            is_ok = False
+
+    return is_ok
+
+
+def _compare_array(path, actual, expect):
+    '''Compare a JSON array.'''
+    is_ok = True
+
+    if not len(actual) == len(expect):
+        _error_length_mismatch(path, len(actual), len(expect))
+        is_ok = False
+
+    for (idx, (a, e)) in enumerate(zip(actual, expect)):
+        sub_error = compare_json(path + [str(idx)], a, e)
+        if sub_error:
+            is_ok = False
+
+    return is_ok
+
+
+def _make_replacements(value):
+    for (old, new) in REPLACEMENTS.values():
+        value = value.replace(old, new)
+    return value
+
+
+def _compare_string(path, actual, expect):
+    '''Compare a JSON string supporting replacements in the expected output.'''
+    expect = _make_replacements(expect)
+
+    if not actual == expect:
+        _error_unexpect_value(path, actual, expect)
+        return False
+    else:
+        print('%s is ok: %s' % (_print_path(path), actual))
+    return True
+
+
+def _compare_number(path, actual, expect):
+    '''Compare a JSON integer.'''
+    if not actual == expect:
+        _error_unexpect_value(path, actual, expect)
+        return False
+    else:
+        print('%s is ok: %s' % (_print_path(path), actual))
+    return True
+
+
+def _inspect_ordering(arr):
+    req_ordering = True
+
+    if not arr:
+        return arr, req_ordering
+
+    if arr[0] == '__P1689_unordered__':
+        arr.pop(0)
+        req_ordering = False
+
+    return arr, req_ordering
+
+
+def compare_json(path, actual, expect):
+    actual_type = type(actual)
+    expect_type = type(expect)
+
+    is_ok = True
+
+    if not actual_type == expect_type:
+        _error_type_mismatch(path, actual_type, expect_type)
+        is_ok = False
+    elif actual_type == dict:
+        is_ok = _compare_object(path, actual, expect)
+    elif actual_type == list:
+        expect, req_ordering = _inspect_ordering(expect)
+        if not req_ordering:
+            actual = set(actual)
+            expect = set(expect)
+        is_ok = _compare_array(path, actual, expect)
+    elif actual_type == str:
+        is_ok = _compare_string(path, actual, expect)
+    elif actual_type == float:
+        is_ok = _compare_number(path, actual, expect)
+    elif actual_type == int:
+        is_ok = _compare_number(path, actual, expect)
+    elif actual_type == bool:
+        is_ok = _compare_number(path, actual, expect)
+    elif actual_type == type(None):
+        pass
+    else:
+        _error_unknown_type(path, actual_type)
+        is_ok = False
+
+    return is_ok
+
+
+def validate_p1689(actual, expect):
+    '''Validate a P1689 file against an expected output file.
+
+    Returns `False` if it fails, `True` if they are the same.
+    '''
+    with open(actual, 'r') as fin:
+        actual_content = fin.read()
+    with open(expect, 'r') as fin:
+        expect_content = fin.read()
+
+    actual_json = json.loads(actual_content)
+    expect_json = json.loads(expect_content)
+
+    return compare_json([], actual_json, expect_json)
+
+
+if __name__ == '__main__':
+    import sys
+
+    actual = None
+    expect = None
+
+    # Parse arguments.
+    args = sys.argv[1:]
+    while args:
+        # Take an argument.
+        arg = args.pop(0)
+
+        # Parse out replacement expressions.
+        if arg == '-r' or arg == '--replace':
+            replacement = args.pop(0)
+            (key, value) = replacement.split('=', maxsplit=1)
+            REPLACEMENTS[key] = value
+        # Flag to change how errors are reported.
+        elif arg == '-A' or arg == '--all':
+            ALL_ERRORS = True
+        # Required arguments.
+        elif arg == '-a' or arg == '--actual':
+            actual = args.pop(0)
+        elif arg == '-e' or arg == '--expect':
+            expect = args.pop(0)
+
+    # Validate that we have the required arguments.
+    if actual is None:
+        raise RuntimeError('missing "actual" file')
+    if expect is None:
+        raise RuntimeError('missing "expect" file')
+
+    # Do the actual work.
+    is_ok = validate_p1689(actual, expect)
+
+    # Fail if errors are found.
+    if not is_ok:
+        sys.exit(1)
diff --git a/gcc/testsuite/lib/modules.exp b/gcc/testsuite/lib/modules.exp
new file mode 100644
index 00000000000..d466a73cbe1
--- /dev/null
+++ b/gcc/testsuite/lib/modules.exp
@@ -0,0 +1,71 @@
+#   Copyright (C) 1997-2022 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with GCC; see the file COPYING3.  If not see
+# <http://www.gnu.org/licenses/>.
+
+# Verify various kinds of gcov output: line counts, branch percentages,
+# and call return percentages.  None of this is language-specific.
+
+load_lib "target-supports.exp"
+
+#
+# clean-p1689-file -- delete a working file the compiler creates for p1689
+#
+# TESTCASE is the name of the test.
+# SUFFIX is file suffix
+
+proc clean-p1689-file { testcase suffix } {
+    set basename [file tail $testcase]
+    set base [file rootname $basename]
+    remote_file host delete $base.$suffix
+}
+
+#
+# clean-p1689 -- delete the working files the compiler creates for p1689
+#
+# TESTCASE is the name of the test.
+#
+proc clean-p1689 { testcase } {
+    clean-p1689-file $testcase "d"
+    clean-p1689-file $testcase "ddi"
+}
+
+# Call by dg-final to check a P1689 dependency file
+
+proc run-check-p1689-valid { depfile template } {
+    global srcdir subdir
+    # Extract the test file name from the arguments.
+    set testcase [file rootname [file tail $depfile]]
+
+    verbose "Running P1689 validation for $testcase in $srcdir/$subdir" 2
+    set testcase [remote_download host $testcase]
+
+    set pytest_script "test-p1689.py"
+    if { ![check_effective_target_recent_python3] } {
+      unsupported "$pytest_script python3 is missing"
+      return
+    }
+
+    verbose "running script" 1
+    spawn -noecho python3 $srcdir/$subdir/$pytest_script --all --actual $depfile --expect $srcdir/$subdir/$template
+
+    expect {
+      -re "ERROR: (\[^\r\n\]*)" {
+       fail $expect_out(0,string)
+       exp_continue
+      }
+    }
+
+    clean-p1689 $testcase
+}
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index aef703f8111..141cfd60eda 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -302,6 +302,9 @@ typedef CPPCHAR_SIGNED_T cppchar_signed_t;
 /* Style of header dependencies to generate.  */
 enum cpp_deps_style { DEPS_NONE = 0, DEPS_USER, DEPS_SYSTEM };
 
+/* Structured format of module dependencies to generate.  */
+enum cpp_fdeps_format { DEPS_FMT_NONE = 0, DEPS_FMT_P1689R5 };
+
 /* The possible normalization levels, from most restrictive to least.  */
 enum cpp_normalize_level {
   /* In NFKC.  */
@@ -589,6 +592,9 @@ struct cpp_options
     /* Style of header dependencies to generate.  */
     enum cpp_deps_style style;
 
+    /* Structured format of module dependencies to generate.  */
+    enum cpp_fdeps_format fdeps_format;
+
     /* Assume missing files are generated files.  */
     bool missing_files;
 
@@ -1112,9 +1118,9 @@ extern void cpp_post_options (cpp_reader *);
 extern void cpp_init_iconv (cpp_reader *);
 
 /* Call this to finish preprocessing.  If you requested dependency
-   generation, pass an open stream to write the information to,
-   otherwise NULL.  It is your responsibility to close the stream.  */
-extern void cpp_finish (cpp_reader *, FILE *deps_stream);
+   generation, pass open stream(s) to write the information to,
+   otherwise NULL.  It is your responsibility to close the stream(s).  */
+extern void cpp_finish (cpp_reader *, FILE *deps_stream, FILE *fdeps_stream = NULL);
 
 /* Call this to release the handle at the end of preprocessing.  Any
    use of the handle after this function returns is invalid.  */
diff --git a/libcpp/include/mkdeps.h b/libcpp/include/mkdeps.h
index 920e2791334..7025e634caf 100644
--- a/libcpp/include/mkdeps.h
+++ b/libcpp/include/mkdeps.h
@@ -53,11 +53,15 @@ extern void deps_add_default_target (class mkdeps *, const char *);
 
 /* Adds a module target.  The module name and cmi name are copied.  */
 extern void deps_add_module_target (struct mkdeps *, const char *module,
-				    const char *cmi, bool is_header);
+				    const char *cmi, bool is_header,
+				    bool is_exported);
 
 /* Adds a module dependency.  The module name is copied.  */
 extern void deps_add_module_dep (struct mkdeps *, const char *module);
 
+/* Add a structured dependency target.  */
+extern void fdeps_add_target (struct mkdeps *, const char *, bool);
+
 /* Add a dependency (appears on the right side of the colon) to the
    deps list.  Dependencies will be printed in the order that they
    were entered with this function.  By convention, the first
@@ -68,6 +72,9 @@ extern void deps_add_dep (class mkdeps *, const char *);
    is the number of columns to word-wrap at (0 means don't wrap).  */
 extern void deps_write (const cpp_reader *, FILE *, unsigned int);
 
+/* Write out a deps buffer to a specified file in P1689R5 format.  */
+extern void deps_write_p1689r5 (const struct mkdeps *, FILE *);
+
 /* Write out a deps buffer to a file, in a form that can be read back
    with deps_restore.  Returns nonzero on error, in which case the
    error number will be in errno.  */
diff --git a/libcpp/init.cc b/libcpp/init.cc
index 693feaa31ed..f974d8f2d41 100644
--- a/libcpp/init.cc
+++ b/libcpp/init.cc
@@ -860,7 +860,7 @@ read_original_directory (cpp_reader *pfile)
    Maybe it should also reset state, such that you could call
    cpp_start_read with a new filename to restart processing.  */
 void
-cpp_finish (cpp_reader *pfile, FILE *deps_stream)
+cpp_finish (struct cpp_reader *pfile, FILE *deps_stream, FILE *fdeps_stream)
 {
   /* Warn about unused macros before popping the final buffer.  */
   if (CPP_OPTION (pfile, warn_unused_macros))
@@ -874,8 +874,15 @@ cpp_finish (cpp_reader *pfile, FILE *deps_stream)
   while (pfile->buffer)
     _cpp_pop_buffer (pfile);
 
-  if (deps_stream)
-    deps_write (pfile, deps_stream, 72);
+  cpp_fdeps_format fdeps_format = CPP_OPTION (pfile, deps.fdeps_format);
+  if (fdeps_format == DEPS_FMT_P1689R5 && fdeps_stream)
+    deps_write_p1689r5 (pfile->deps, fdeps_stream);
+
+  if (CPP_OPTION (pfile, deps.style) != DEPS_NONE
+      && deps_stream)
+    {
+      deps_write (pfile, deps_stream, 72);
+    }
 
   /* Report on headers that could use multiple include guards.  */
   if (CPP_OPTION (pfile, print_include_names))
diff --git a/libcpp/mkdeps.cc b/libcpp/mkdeps.cc
index 8f9585c3c0a..762bde6ea55 100644
--- a/libcpp/mkdeps.cc
+++ b/libcpp/mkdeps.cc
@@ -81,7 +81,8 @@ public:
   };
 
   mkdeps ()
-    : module_name (NULL), cmi_name (NULL), is_header_unit (false), quote_lwm (0)
+    : primary_output (NULL), module_name (NULL), cmi_name (NULL)
+    , is_header_unit (false), is_exported (false), quote_lwm (0)
   {
   }
   ~mkdeps ()
@@ -90,6 +91,9 @@ public:
 
     for (i = targets.size (); i--;)
       free (const_cast <char *> (targets[i]));
+    free (const_cast <char *> (primary_output));
+    for (i = fdeps_targets.size (); i--;)
+      free (const_cast <char *> (fdeps_targets[i]));
     for (i = deps.size (); i--;)
       free (const_cast <char *> (deps[i]));
     for (i = vpath.size (); i--;)
@@ -103,6 +107,8 @@ public:
 public:
   vec<const char *> targets;
   vec<const char *> deps;
+  const char * primary_output;
+  vec<const char *> fdeps_targets;
   vec<velt> vpath;
   vec<const char *> modules;
 
@@ -110,6 +116,7 @@ public:
   const char *module_name;
   const char *cmi_name;
   bool is_header_unit;
+  bool is_exported;
   unsigned short quote_lwm;
 };
 
@@ -288,6 +295,26 @@ deps_add_default_target (class mkdeps *d, const char *tgt)
     }
 }
 
+/* Adds a target O.  We make a copy, so it need not be a permanent
+   string.
+
+   This is the target associated with the rule that (in a C++ modules build)
+   compiles the source that is being scanned for dynamic dependencies.  It is
+   used to associate the structured dependency information with that rule as
+   needed.  */
+void
+fdeps_add_target (struct mkdeps *d, const char *o, bool is_primary)
+{
+  o = apply_vpath (d, o);
+  if (is_primary)
+  {
+    if (d->primary_output)
+      d->fdeps_targets.push (d->primary_output);
+    d->primary_output = xstrdup (o);
+  } else
+    d->fdeps_targets.push (xstrdup (o));
+}
+
 void
 deps_add_dep (class mkdeps *d, const char *t)
 {
@@ -325,12 +352,13 @@ deps_add_vpath (class mkdeps *d, const char *vpath)
 
 void
 deps_add_module_target (struct mkdeps *d, const char *m,
-			const char *cmi, bool is_header_unit)
+			const char *cmi, bool is_header_unit, bool is_exported)
 {
   gcc_assert (!d->module_name);
   
   d->module_name = xstrdup (m);
   d->is_header_unit = is_header_unit;
+  d->is_exported = is_exported;
   d->cmi_name = xstrdup (cmi);
 }
 
@@ -395,10 +423,16 @@ make_write (const cpp_reader *pfile, FILE *fp, unsigned int colmax)
   if (colmax && colmax < 34)
     colmax = 34;
 
+  /* Write out C++ modules information if no other `-fdeps-format=`
+     option is given. */
+  cpp_fdeps_format fdeps_format = CPP_OPTION (pfile, deps.fdeps_format);
+  bool write_make_modules_deps = fdeps_format == DEPS_FMT_NONE &&
+    CPP_OPTION (pfile, deps.modules);
+
   if (d->deps.size ())
     {
       column = make_write_vec (d->targets, fp, 0, colmax, d->quote_lwm);
-      if (CPP_OPTION (pfile, deps.modules) && d->cmi_name)
+      if (write_make_modules_deps && d->cmi_name)
 	column = make_write_name (d->cmi_name, fp, column, colmax);
       fputs (":", fp);
       column++;
@@ -409,7 +443,7 @@ make_write (const cpp_reader *pfile, FILE *fp, unsigned int colmax)
 	  fprintf (fp, "%s:\n", munge (d->deps[i]));
     }
 
-  if (!CPP_OPTION (pfile, deps.modules))
+  if (!write_make_modules_deps)
     return;
 
   if (d->modules.size ())
@@ -473,6 +507,117 @@ deps_write (const cpp_reader *pfile, FILE *fp, unsigned int colmax)
   make_write (pfile, fp, colmax);
 }
 
+static void
+p1689r5_write_filepath (const char *name, FILE *fp)
+{
+  if (cpp_valid_utf8_p (name, strlen (name)))
+    {
+      fputc ('"', fp);
+      for (const char* c = name; *c; c++)
+	{
+	  // Escape control characters.
+	  if (ISCNTRL (*c))
+	    fprintf (fp, "\\u%04x", *c);
+	  // JSON escape characters.
+	  else if (*c == '"' || *c == '\\')
+	    {
+	      fputc ('\\', fp);
+	      fputc (*c, fp);
+	    }
+	  // Everything else.
+	  else
+	    fputc (*c, fp);
+	}
+      fputc ('"', fp);
+    }
+  else
+    {
+      // TODO: print an error
+    }
+}
+
+static void
+p1689r5_write_vec (const mkdeps::vec<const char *> &vec, FILE *fp)
+{
+  for (unsigned ix = 0; ix != vec.size (); ix++)
+    {
+      p1689r5_write_filepath (vec[ix], fp);
+      if (ix < vec.size () - 1)
+	fputc (',', fp);
+      fputc ('\n', fp);
+    }
+}
+
+/* Ideally this (and the above `p1689r5_` functions) would use `gcc/json.h`,
+   but since this is `libcpp`, we cannot use `gcc/` code.
+
+  TODO: move `json.h` to libiberty.  */
+void
+deps_write_p1689r5 (const struct mkdeps *d, FILE *fp)
+{
+  fputs ("{\n", fp);
+
+  fputs ("\"rules\": [\n", fp);
+  fputs ("{\n", fp);
+
+  if (d->primary_output)
+    {
+      fputs ("\"primary-output\": ", fp);
+      p1689r5_write_filepath (d->primary_output, fp);
+      fputs (",\n", fp);
+    }
+
+  if (d->fdeps_targets.size ())
+    {
+      fputs ("\"outputs\": [\n", fp);
+      p1689r5_write_vec (d->fdeps_targets, fp);
+      fputs ("],\n", fp);
+    }
+
+  if (d->module_name)
+    {
+      fputs ("\"provides\": [\n", fp);
+      fputs ("{\n", fp);
+
+      fputs ("\"logical-name\": ", fp);
+      p1689r5_write_filepath (d->module_name, fp);
+      fputs (",\n", fp);
+
+      fprintf (fp, "\"is-interface\": %s\n", d->is_exported ? "true" : "false");
+
+      // TODO: header-unit information
+
+      fputs ("}\n", fp);
+      fputs ("],\n", fp);
+    }
+
+  fputs ("\"requires\": [\n", fp);
+  for (size_t i = 0; i < d->modules.size (); i++)
+    {
+      if (i != 0)
+	fputs (",\n", fp);
+      fputs ("{\n", fp);
+
+      fputs ("\"logical-name\": ", fp);
+      p1689r5_write_filepath (d->modules[i], fp);
+      fputs ("\n", fp);
+
+      // TODO: header-unit information
+
+      fputs ("}\n", fp);
+    }
+  fputs ("]\n", fp);
+
+  fputs ("}\n", fp);
+
+  fputs ("],\n", fp);
+
+  fputs ("\"version\": 0,\n", fp);
+  fputs ("\"revision\": 0\n", fp);
+
+  fputs ("}\n", fp);
+}
+
 /* Write out a deps buffer to a file, in a form that can be read back
    with deps_restore.  Returns nonzero on error, in which case the
    error number will be in errno.  */
-- 
2.40.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH v7 3/4] c++modules: report imported CMI files as dependencies
  2023-07-02 16:32 [PATCH v7 0/4] P1689R5 support Ben Boeckel
  2023-07-02 16:32 ` [PATCH v7 1/4] spec: add a spec function to join arguments Ben Boeckel
  2023-07-02 16:32 ` [PATCH v7 2/4] p1689r5: initial support Ben Boeckel
@ 2023-07-02 16:32 ` Ben Boeckel
  2023-07-02 16:32 ` [PATCH v7 4/4] c++modules: report module mapper files as a dependency Ben Boeckel
  3 siblings, 0 replies; 8+ messages in thread
From: Ben Boeckel @ 2023-07-02 16:32 UTC (permalink / raw)
  To: gcc-patches; +Cc: Ben Boeckel, jason, nathan, fortran, gcc, brad.king

They affect the build, so report them via `-MF` mechanisms.

gcc/cp/

	* module.cc (do_import): Report imported CMI files as
	dependencies.

gcc/testsuite/

	* g++.dg/modules/depreport-1_a.C: New test.
	* g++.dg/modules/depreport-1_b.C: New test.
	* g++.dg/modules/test-depfile.py: New tool for validating depfile
	information.
	* lib/modules.exp: Support for validating depfile contents.

Signed-off-by: Ben Boeckel <ben.boeckel@kitware.com>
---
 gcc/cp/module.cc                             |   3 +
 gcc/testsuite/g++.dg/modules/depreport-1_a.C |  10 +
 gcc/testsuite/g++.dg/modules/depreport-1_b.C |  12 ++
 gcc/testsuite/g++.dg/modules/test-depfile.py | 187 +++++++++++++++++++
 gcc/testsuite/lib/modules.exp                |  29 +++
 5 files changed, 241 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-1_a.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-1_b.C
 create mode 100644 gcc/testsuite/g++.dg/modules/test-depfile.py

diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index 9df60d695b1..f3acc4e02fe 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -18968,6 +18968,9 @@ module_state::do_import (cpp_reader *reader, bool outermost)
       dump () && dump ("CMI is %s", file);
       if (note_module_cmi_yes || inform_cmi_p)
 	inform (loc, "reading CMI %qs", file);
+      /* Add the CMI file to the dependency tracking. */
+      if (cpp_get_deps (reader))
+	deps_add_dep (cpp_get_deps (reader), file);
       fd = open (file, O_RDONLY | O_CLOEXEC | O_BINARY);
       e = errno;
     }
diff --git a/gcc/testsuite/g++.dg/modules/depreport-1_a.C b/gcc/testsuite/g++.dg/modules/depreport-1_a.C
new file mode 100644
index 00000000000..241701728a2
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depreport-1_a.C
@@ -0,0 +1,10 @@
+// { dg-additional-options -fmodules-ts }
+
+export module Foo;
+// { dg-module-cmi Foo }
+
+export class Base
+{
+public:
+  int m;
+};
diff --git a/gcc/testsuite/g++.dg/modules/depreport-1_b.C b/gcc/testsuite/g++.dg/modules/depreport-1_b.C
new file mode 100644
index 00000000000..b6e317c6703
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depreport-1_b.C
@@ -0,0 +1,12 @@
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -MD }
+// { dg-additional-options "-MF depreport-1.d" }
+
+import Foo;
+
+void foo ()
+{
+  Base b;
+}
+
+// { dg-final { run-check-module-dep-expect-input "depreport-1.d" "gcm.cache/Foo.gcm" } }
diff --git a/gcc/testsuite/g++.dg/modules/test-depfile.py b/gcc/testsuite/g++.dg/modules/test-depfile.py
new file mode 100644
index 00000000000..ea4edb61434
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/test-depfile.py
@@ -0,0 +1,187 @@
+import json
+
+
+# Parameters.
+ALL_ERRORS = False
+
+
+def _report_error(msg):
+    '''Report an error.'''
+    full_msg = 'ERROR: ' + msg
+    if ALL_ERRORS:
+        print(full_msg)
+    else:
+        raise RuntimeError(full_msg)
+
+
+class Token(object):
+    pass
+
+
+class Output(Token):
+    def __init__(self, path):
+        self.path = path
+
+
+class Input(Token):
+    def __init__(self, path):
+        self.path = path
+
+
+class Colon(Token):
+    pass
+
+
+class Append(Token):
+    pass
+
+
+class Variable(Token):
+    def __init__(self, name):
+        self.name = name
+
+
+class Word(Token):
+    def __init__(self, name):
+        self.name = name
+
+
+def validate_depfile(depfile, expect_input=None):
+    '''Validate a depfile contains some information
+
+    Returns `False` if the information is not found.
+    '''
+    with open(depfile, 'r') as fin:
+        depfile_content = fin.read()
+
+    real_lines = []
+    join_line = False
+    for line in depfile_content.split('\n'):
+        # Join the line if needed.
+        if join_line:
+            line = real_lines.pop() + line
+
+        # Detect line continuations.
+        join_line = line.endswith('\\')
+        # Strip line continuation characters.
+        if join_line:
+            line = line[:-1]
+
+        # Add to the real line set.
+        real_lines.append(line)
+
+    # Perform tokenization.
+    tokenized_lines = []
+    for line in real_lines:
+        tokenized = []
+        join_word = False
+        for word in line.split(' '):
+            if join_word:
+                word = tokenized.pop() + ' ' + word
+
+            # Detect word joins.
+            join_word = word.endswith('\\')
+            # Strip escape character.
+            if join_word:
+                word = word[:-1]
+
+            # Detect `:` at the end of a word.
+            if word.endswith(':'):
+                tokenized.append(word[:-1])
+                word = word[-1]
+
+            # Add word to the tokenized set.
+            tokenized.append(word)
+
+        tokenized_lines.append(tokenized)
+
+    # Parse.
+    ast = []
+    for line in tokenized_lines:
+        kind = None
+        for token in line:
+            if token == ':':
+                kind = 'dependency'
+            elif token == '+=':
+                kind = 'append'
+        if line == ['']:
+            kind = 'empty'
+
+        if kind is None:
+            _report_error('unknown line kind: %s' % line)
+
+        line_parse = []
+        if kind == 'dependency':
+            after_colon = False
+            for token in line:
+                if token == ':':
+                    after_colon = True
+                elif after_colon:
+                    line_parse.append(Input(token))
+                else:
+                    line_parse.append(Output(token))
+        elif kind == 'append':
+            after_op = False
+            for token in line:
+                if token == '+=':
+                    after_op = True
+                elif after_op:
+                    line_parse.append(Word(token))
+                else:
+                    line_parse.append(Variable(token))
+
+        ast.append(line_parse)
+
+    for node in ast:
+        for token in node:
+            if expect_input is not None:
+                # If the input is found, clear the expectation.
+                if isinstance(token, Input) and token.path == expect_input:
+                    expect_input = None
+
+    result = True
+    if expect_input:
+        _report_error('missing input: %s' % expect_input)
+        result = False
+
+    return result
+
+
+if __name__ == '__main__':
+    import sys
+
+    depfile = None
+    have_expect = False
+    expect_input = None
+
+    # Parse arguments.
+    args = sys.argv[1:]
+    while args:
+        # Take an argument.
+        arg = args.pop(0)
+
+        # Flag to change how errors are reported.
+        if arg == '-A' or arg == '--all':
+            ALL_ERRORS = True
+        # Required arguments.
+        elif arg == '-d' or arg == '--depfile':
+            depfile = args.pop(0)
+        elif arg == '-i' or arg == '--expect-input':
+            expect_input = args.pop(0)
+            have_expect = True
+
+    # Validate that we have the required arguments.
+    if depfile is None:
+        raise RuntimeError('missing "depfile" file')
+    if have_expect is None:
+        raise RuntimeError('missing an "expect" argument')
+
+    # Do the actual work.
+    try:
+        is_ok = validate_depfile(depfile, expect_input=expect_input)
+    except BaseException as e:
+        _report_error('exception: %s' % e)
+
+    # Fail if errors are found.
+    if not is_ok:
+        sys.exit(1)
diff --git a/gcc/testsuite/lib/modules.exp b/gcc/testsuite/lib/modules.exp
index d466a73cbe1..e24ee7618d9 100644
--- a/gcc/testsuite/lib/modules.exp
+++ b/gcc/testsuite/lib/modules.exp
@@ -69,3 +69,32 @@ proc run-check-p1689-valid { depfile template } {
 
     clean-p1689 $testcase
 }
+
+proc run-check-module-dep { depfile flag expected } {
+    global srcdir subdir
+    # Extract the test file name from the arguments.
+    set testcase [file rootname [file tail $depfile]]
+
+    verbose "Verifying dependencies for $testcase in $srcdir/$subdir" 2
+    set testcase [remote_download host $testcase]
+
+    set pytest_script "test-depfile.py"
+    if { ![check_effective_target_recent_python3] } {
+      unsupported "$pytest_script python3 is missing"
+      return
+    }
+
+    verbose "running script test-depfile.py" 1
+    spawn -noecho python3 $srcdir/$subdir/$pytest_script --all --depfile $depfile $flag $expected
+
+    expect {
+      -re "ERROR: (\[^\r\n\]*)" {
+       fail $expect_out(0,string)
+       exp_continue
+      }
+    }
+}
+
+proc run-check-module-dep-expect-input { depfile expected } {
+    run-check-module-dep $depfile "--expect-input" $expected
+}
-- 
2.40.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH v7 4/4] c++modules: report module mapper files as a dependency
  2023-07-02 16:32 [PATCH v7 0/4] P1689R5 support Ben Boeckel
                   ` (2 preceding siblings ...)
  2023-07-02 16:32 ` [PATCH v7 3/4] c++modules: report imported CMI files as dependencies Ben Boeckel
@ 2023-07-02 16:32 ` Ben Boeckel
  3 siblings, 0 replies; 8+ messages in thread
From: Ben Boeckel @ 2023-07-02 16:32 UTC (permalink / raw)
  To: gcc-patches; +Cc: Ben Boeckel, jason, nathan, fortran, gcc, brad.king

It affects the build, and if used as a static file, can reliably be
tracked using the `-MF` mechanism.

gcc/cp/:

	* mapper-client.cc, mapper-client.h (open_module_client): Accept
	dependency tracking and track module mapper files as
	dependencies.
	* module.cc (make_mapper, get_mapper): Pass the dependency
	tracking class down.

gcc/testsuite/:

	* g++.dg/modules/depreport-2.modmap: New test.
	* g++.dg/modules/depreport-2_a.C: New test.
	* g++.dg/modules/depreport-2_b.C: New test.
	* g++.dg/modules/test-depfile.py: Support `:|` syntax output
	when generating modules.

Signed-off-by: Ben Boeckel <ben.boeckel@kitware.com>
---
 gcc/cp/mapper-client.cc                       |  5 +++++
 gcc/cp/mapper-client.h                        |  1 +
 gcc/cp/module.cc                              | 18 ++++++++---------
 .../g++.dg/modules/depreport-2.modmap         |  2 ++
 gcc/testsuite/g++.dg/modules/depreport-2_a.C  | 15 ++++++++++++++
 gcc/testsuite/g++.dg/modules/depreport-2_b.C  | 14 +++++++++++++
 gcc/testsuite/g++.dg/modules/test-depfile.py  | 20 +++++++++++++++++++
 7 files changed, 66 insertions(+), 9 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-2.modmap
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-2_a.C
 create mode 100644 gcc/testsuite/g++.dg/modules/depreport-2_b.C

diff --git a/gcc/cp/mapper-client.cc b/gcc/cp/mapper-client.cc
index 39e80df2d25..92727195246 100644
--- a/gcc/cp/mapper-client.cc
+++ b/gcc/cp/mapper-client.cc
@@ -34,6 +34,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "diagnostic-core.h"
 #include "mapper-client.h"
 #include "intl.h"
+#include "mkdeps.h"
 
 #include "../../c++tools/resolver.h"
 
@@ -132,6 +133,7 @@ spawn_mapper_program (char const **errmsg, std::string &name,
 
 module_client *
 module_client::open_module_client (location_t loc, const char *o,
+				   class mkdeps *deps,
 				   void (*set_repo) (const char *),
 				   char const *full_program_name)
 {
@@ -285,6 +287,9 @@ module_client::open_module_client (location_t loc, const char *o,
 	  errmsg = "opening";
 	else
 	  {
+	    /* Add the mapper file to the dependency tracking. */
+	    if (deps)
+	      deps_add_dep (deps, name.c_str ());
 	    if (int l = r->read_tuple_file (fd, ident, false))
 	      {
 		if (l > 0)
diff --git a/gcc/cp/mapper-client.h b/gcc/cp/mapper-client.h
index b32723ce296..a3b0b8adc51 100644
--- a/gcc/cp/mapper-client.h
+++ b/gcc/cp/mapper-client.h
@@ -55,6 +55,7 @@ public:
 
 public:
   static module_client *open_module_client (location_t loc, const char *option,
+					    class mkdeps *,
 					    void (*set_repo) (const char *),
 					    char const *);
   static void close_module_client (location_t loc, module_client *);
diff --git a/gcc/cp/module.cc b/gcc/cp/module.cc
index f3acc4e02fe..77c9edcbc04 100644
--- a/gcc/cp/module.cc
+++ b/gcc/cp/module.cc
@@ -3969,12 +3969,12 @@ static GTY(()) vec<tree, va_gc> *partial_specializations;
 /* Our module mapper (created lazily).  */
 module_client *mapper;
 
-static module_client *make_mapper (location_t loc);
-inline module_client *get_mapper (location_t loc)
+static module_client *make_mapper (location_t loc, class mkdeps *deps);
+inline module_client *get_mapper (location_t loc, class mkdeps *deps)
 {
   auto *res = mapper;
   if (!res)
-    res = make_mapper (loc);
+    res = make_mapper (loc, deps);
   return res;
 }
 
@@ -14033,7 +14033,7 @@ get_module (const char *ptr)
 /* Create a new mapper connecting to OPTION.  */
 
 module_client *
-make_mapper (location_t loc)
+make_mapper (location_t loc, class mkdeps *deps)
 {
   timevar_start (TV_MODULE_MAPPER);
   const char *option = module_mapper_name;
@@ -14041,7 +14041,7 @@ make_mapper (location_t loc)
     option = getenv ("CXX_MODULE_MAPPER");
 
   mapper = module_client::open_module_client
-    (loc, option, &set_cmi_repo,
+    (loc, option, deps, &set_cmi_repo,
      (save_decoded_options[0].opt_index == OPT_SPECIAL_program_name)
      && save_decoded_options[0].arg != progname
      ? save_decoded_options[0].arg : nullptr);
@@ -19506,7 +19506,7 @@ maybe_translate_include (cpp_reader *reader, line_maps *lmaps, location_t loc,
   dump.push (NULL);
 
   dump () && dump ("Checking include translation '%s'", path);
-  auto *mapper = get_mapper (cpp_main_loc (reader));
+  auto *mapper = get_mapper (cpp_main_loc (reader), cpp_get_deps (reader));
 
   size_t len = strlen (path);
   path = canonicalize_header_name (NULL, loc, true, path, len);
@@ -19622,7 +19622,7 @@ module_begin_main_file (cpp_reader *reader, line_maps *lmaps,
 static void
 name_pending_imports (cpp_reader *reader)
 {
-  auto *mapper = get_mapper (cpp_main_loc (reader));
+  auto *mapper = get_mapper (cpp_main_loc (reader), cpp_get_deps (reader));
 
   if (!vec_safe_length (pending_imports))
     /* Not doing anything.  */
@@ -20092,7 +20092,7 @@ init_modules (cpp_reader *reader)
 
   if (!flag_module_lazy)
     /* Get the mapper now, if we're not being lazy.  */
-    get_mapper (cpp_main_loc (reader));
+    get_mapper (cpp_main_loc (reader), cpp_get_deps (reader));
 
   if (!flag_preprocess_only)
     {
@@ -20302,7 +20302,7 @@ late_finish_module (cpp_reader *reader,  module_processing_cookie *cookie,
 
   if (!errorcount)
     {
-      auto *mapper = get_mapper (cpp_main_loc (reader));
+      auto *mapper = get_mapper (cpp_main_loc (reader), cpp_get_deps (reader));
       mapper->ModuleCompiled (state->get_flatname ());
     }
   else if (cookie->cmi_name)
diff --git a/gcc/testsuite/g++.dg/modules/depreport-2.modmap b/gcc/testsuite/g++.dg/modules/depreport-2.modmap
new file mode 100644
index 00000000000..ff271df883a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depreport-2.modmap
@@ -0,0 +1,2 @@
+$root .
+Foo     Foo.gcm
diff --git a/gcc/testsuite/g++.dg/modules/depreport-2_a.C b/gcc/testsuite/g++.dg/modules/depreport-2_a.C
new file mode 100644
index 00000000000..6912de16333
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depreport-2_a.C
@@ -0,0 +1,15 @@
+// { dg-do preprocess }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fmodule-mapper=[srcdir]/depreport-2.modmap }
+// { dg-additional-options -MD }
+// { dg-additional-options "-MF depreport-2_a.d" }
+
+export module Foo;
+
+export class Base
+{
+public:
+  int m;
+};
+
+// { dg-final { run-check-module-dep-expect-input "depreport-2_a.d" "[srcdir]/depreport-2.modmap" } }
diff --git a/gcc/testsuite/g++.dg/modules/depreport-2_b.C b/gcc/testsuite/g++.dg/modules/depreport-2_b.C
new file mode 100644
index 00000000000..d94d6a297a0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/modules/depreport-2_b.C
@@ -0,0 +1,14 @@
+// { dg-do preprocess }
+// { dg-additional-options -fmodules-ts }
+// { dg-additional-options -fmodule-mapper=[srcdir]/depreport-2.modmap }
+// { dg-additional-options -MD }
+// { dg-additional-options "-MF depreport-2_b.d" }
+
+import Foo;
+
+void foo ()
+{
+  Base b;
+}
+
+// { dg-final { run-check-module-dep-expect-input "depreport-2_b.d" "[srcdir]/depreport-2.modmap" } }
diff --git a/gcc/testsuite/g++.dg/modules/test-depfile.py b/gcc/testsuite/g++.dg/modules/test-depfile.py
index ea4edb61434..9693c058ece 100644
--- a/gcc/testsuite/g++.dg/modules/test-depfile.py
+++ b/gcc/testsuite/g++.dg/modules/test-depfile.py
@@ -28,6 +28,11 @@ class Input(Token):
         self.path = path
 
 
+class OrderInput(Token):
+    def __init__(self, path):
+        self.path = path
+
+
 class Colon(Token):
     pass
 
@@ -89,6 +94,10 @@ def validate_depfile(depfile, expect_input=None):
             if word.endswith(':'):
                 tokenized.append(word[:-1])
                 word = word[-1]
+            # Detect `:` at the end of a word.
+            if word.endswith(':|'):
+                tokenized.append(word[:-2])
+                word = word[-2]
 
             # Add word to the tokenized set.
             tokenized.append(word)
@@ -104,6 +113,8 @@ def validate_depfile(depfile, expect_input=None):
                 kind = 'dependency'
             elif token == '+=':
                 kind = 'append'
+            elif token == ':|':
+                kind = 'order-only'
         if line == ['']:
             kind = 'empty'
 
@@ -120,6 +131,15 @@ def validate_depfile(depfile, expect_input=None):
                     line_parse.append(Input(token))
                 else:
                     line_parse.append(Output(token))
+        elif kind == 'order-only':
+            after_op = False
+            for token in line:
+                if token == ':|':
+                    after_op = True
+                elif after_op:
+                    line_parse.append(OrderInput(token))
+                else:
+                    line_parse.append(Output(token))
         elif kind == 'append':
             after_op = False
             for token in line:
-- 
2.40.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v7 1/4] driver: add a spec function to join arguments
  2023-07-02 16:32 ` [PATCH v7 1/4] spec: add a spec function to join arguments Ben Boeckel
@ 2023-08-23 19:29   ` Jason Merrill
  2023-08-23 21:29     ` Joseph Myers
  0 siblings, 1 reply; 8+ messages in thread
From: Jason Merrill @ 2023-08-23 19:29 UTC (permalink / raw)
  To: Ben Boeckel, gcc-patches, Joseph S. Myers; +Cc: brad.king

[-- Attachment #1: Type: text/plain, Size: 1798 bytes --]

On 7/2/23 12:32, Ben Boeckel wrote:
> When passing `-o` flags to other options, the typical `-o foo` spelling
> leaves a leading whitespace when replacing elsewhere. This ends up
> creating flags spelled as `-some-option-with-arg= foo.ext` which doesn't
> parse properly. When attempting to make a spec function to just remove
> the leading whitespace, the argument splitting ends up masking the
> whitespace. However, the intended extension *also* ends up being its own
> argument.

Odd.  I looked into this to figure out what was going on, and now I 
understand: when process_brace_body handles e.g. %{o*:-fjoined=%.x%*}, 
first it replaces $* with the rest of the flag, i.e. "", resulting in 
-fjoined=, and then adds the argument as a separate argument to the 
result of substitution.  This seems strange, but works fine for the 
existing uses that build one Separate switch from another.

The other oddity you mention comes from

>   /* End of string.  If we are processing a spec function, we need to                                                               
>      end any pending argument.  */
>   if (processing_spec_function)
>     end_going_arg ();

so that when give_switch calls do_spec_1 twice for the basename and 
suffix, they end up as separate arguments to the spec function.  I don't 
know the purpose of this code; it doesn't seem to have been necessary 
for the if-exists spec function that was added in the same patch 
(r59241).  Removing this doesn't seem to break anything for me.

The join function works around both of these issues.  But I notice that 
the use of reconcat is a memory leak, and since we have the obstack 
available I've tweaked the function to use it.  I also added some 
documentation.

Joseph, any thoughts on these issues or the workaround?

Jason

[-- Attachment #2: 0001-driver-add-a-spec-function-to-join-arguments.patch --]
[-- Type: text/x-patch, Size: 4069 bytes --]

From ca7c76c5b44e76e8596bf8db68d6210fd9ddf113 Mon Sep 17 00:00:00 2001
From: Ben Boeckel <ben.boeckel@kitware.com>
Date: Sun, 2 Jul 2023 12:32:08 -0400
Subject: [PATCH] driver: add a spec function to join arguments
To: gcc-patches@gcc.gnu.org

When passing `-o` flags to other options, the typical `-o foo` spelling
leaves a leading whitespace when replacing elsewhere. This ends up
creating flags spelled as `-some-option-with-arg= foo.ext` which doesn't
parse properly. When attempting to make a spec function to just remove
the leading whitespace, the argument splitting ends up masking the
whitespace. However, the intended extension *also* ends up being its own
argument. To perform the desired behavior, the arguments need to be
concatenated together.

gcc/:

	* gcc.cc (join_spec_func): Add a spec function to join all
	arguments.
	* doc/invoke.texi: Document it.

Signed-off-by: Ben Boeckel <ben.boeckel@kitware.com>
Co-authored-by: Jason Merrill <jason@redhat.com>
---
 gcc/doc/invoke.texi | 10 ++++++++++
 gcc/gcc.cc          | 23 +++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index ef3f4098986..7c475ee5c82 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -35236,6 +35236,16 @@ usage:
 -l%:if-exists-then-else(%:getenv(VSB_DIR rtnet.h) rtnet net)
 @end smallexample
 
+@item @code{join}
+The @code{join} spec function returns the concatenation of its
+arguments.  This is currently used to build e.g. @samp{-fjoined=foo.b}
+from @samp{-fseparate foo.a}, as the behavior of @samp{%*} without this
+function produces the broken @samp{-fjoined= foo.b} instead.
+
+@smallexample
+%@{-fseparate*:-fjoined=%:join(%.b%*)@}
+@end smallexample
+
 @item @code{sanitize}
 The @code{sanitize} spec function takes no arguments.  It returns non-NULL if
 any address, thread or undefined behavior sanitizers are active.
diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index fdfac0b4fe4..4c4e81dee50 100644
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -447,6 +447,7 @@ static const char *greater_than_spec_func (int, const char **);
 static const char *debug_level_greater_than_spec_func (int, const char **);
 static const char *dwarf_version_greater_than_spec_func (int, const char **);
 static const char *find_fortran_preinclude_file (int, const char **);
+static const char *join_spec_func (int, const char **);
 static char *convert_white_space (char *);
 static char *quote_spec (char *);
 static char *quote_spec_arg (char *);
@@ -1772,6 +1773,7 @@ static const struct spec_function static_spec_functions[] =
   { "debug-level-gt",		debug_level_greater_than_spec_func },
   { "dwarf-version-gt",		dwarf_version_greater_than_spec_func },
   { "fortran-preinclude-file",	find_fortran_preinclude_file},
+  { "join",			join_spec_func},
 #ifdef EXTRA_SPEC_FUNCTIONS
   EXTRA_SPEC_FUNCTIONS
 #endif
@@ -10975,6 +10977,27 @@ find_fortran_preinclude_file (int argc, const char **argv)
   return result;
 }
 
+/* The function takes any number of arguments and joins them together.
+
+   This seems to be necessary to build "-fjoined=foo.b" from "-fseparate foo.a"
+   with a %{fseparate*:-fjoined=%.b$*} rule without adding undesired spaces:
+   when doing $* replacement we first replace $* with the rest of the switch
+   (in this case ""), and then add any arguments as arguments after the result,
+   resulting in "-fjoined= foo.b".  Using this function with e.g.
+   %{fseparate*:-fjoined=%:join(%.b$*)} gets multiple words as separate argv
+   elements instead of separated by spaces, and we paste them together.  */
+
+static const char *
+join_spec_func (int argc, const char **argv)
+{
+  if (argc == 1)
+    return argv[0];
+  for (int i = 0; i < argc; ++i)
+    obstack_grow (&obstack, argv[i], strlen (argv[i]));
+  obstack_1grow (&obstack, '\0');
+  return XOBFINISH (&obstack, const char *);
+}
+
 /* If any character in ORIG fits QUOTE_P (_, P), reallocate the string
    so as to precede every one of them with a backslash.  Return the
    original string or the reallocated one.  */
-- 
2.39.3


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v7 2/4] p1689r5: initial support
  2023-07-02 16:32 ` [PATCH v7 2/4] p1689r5: initial support Ben Boeckel
@ 2023-08-23 19:37   ` Jason Merrill
  0 siblings, 0 replies; 8+ messages in thread
From: Jason Merrill @ 2023-08-23 19:37 UTC (permalink / raw)
  To: Ben Boeckel, gcc-patches; +Cc: nathan, fortran, gcc, brad.king

On 7/2/23 12:32, Ben Boeckel wrote:
> This patch implements support for [P1689R5][] to communicate to a build
> system the C++20 module dependencies to build systems so that they may
> build `.gcm` files in the proper order.
> 
> Support is communicated through the following three new flags:
> 
> - `-fdeps-format=` specifies the format for the output. Currently named
>    `p1689r5`.
> 
> - `-fdeps-file=` specifies the path to the file to write the format to.
> 
> - `-fdeps-target=` specifies the `.o` that will be written for the TU
>    that is scanned. This is required so that the build system can
>    correlate the dependency output with the actual compilation that will
>    occur.
> 
> CMake supports this format as of 17 Jun 2022 (to be part of 3.25.0)
> using an experimental feature selection (to allow for future usage
> evolution without committing to how it works today). While it remains
> experimental, docs may be found in CMake's documentation for
> experimental features.
> 
> Future work may include using this format for Fortran module
> dependencies as well, however this is still pending work.
> 
> [P1689R5]: https://isocpp.org/files/papers/P1689R5.html
> [cmake-experimental]: https://gitlab.kitware.com/cmake/cmake/-/blob/master/Help/dev/experimental.rst
> 
> TODO:
> 
> - header-unit information fields
> 
> Header units (including the standard library headers) are 100%
> unsupported right now because the `-E` mechanism wants to import their
> BMIs. A new mode (i.e., something more workable than existing `-E`
> behavior) that mocks up header units as if they were imported purely
> from their path and content would be required.
> 
> - non-utf8 paths
> 
> The current standard says that paths that are not unambiguously
> represented using UTF-8 are not supported (because these cases are rare
> and the extra complication is not worth it at this time). Future
> versions of the format might have ways of encoding non-UTF-8 paths. For
> now, this patch just doesn't support non-UTF-8 paths (ignoring the
> "unambiguously representable in UTF-8" case).
> 
> - figure out why junk gets placed at the end of the file
> 
> Sometimes it seems like the file gets a lot of `NUL` bytes appended to
> it. It happens rarely and seems to be the result of some
> `ftruncate`-style call which results in extra padding in the contents.
> Noting it here as an observation at least.

Thank you for your patience, just a few tweaks left and I think we can 
put this all in this week or next.

> diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
> index aef703f8111..141cfd60eda 100644
> --- a/libcpp/include/cpplib.h
> +++ b/libcpp/include/cpplib.h
> @@ -302,6 +302,9 @@ typedef CPPCHAR_SIGNED_T cppchar_signed_t;
>   /* Style of header dependencies to generate.  */
>   enum cpp_deps_style { DEPS_NONE = 0, DEPS_USER, DEPS_SYSTEM };
>   
> +/* Structured format of module dependencies to generate.  */
> +enum cpp_fdeps_format { DEPS_FMT_NONE = 0, DEPS_FMT_P1689R5 };

These should be FDEPS_FMT_* or just FDEPS_*.

> @@ -395,10 +423,16 @@ make_write (const cpp_reader *pfile, FILE *fp, unsigned int colmax)
>    if (colmax && colmax < 34)
>      colmax = 34;
>  
> +  /* Write out C++ modules information if no other `-fdeps-format=`
> +     option is given. */
> +  cpp_fdeps_format fdeps_format = CPP_OPTION (pfile, deps.fdeps_format);
> +  bool write_make_modules_deps = fdeps_format == DEPS_FMT_NONE &&
> +    CPP_OPTION (pfile, deps.modules);

We typically format an expression like this as:

> +  bool write_make_modules_deps = (fdeps_format == FDEPS_FMT_NONE
> +                                 && CPP_OPTION (pfile, deps.modules));

> @@ -473,6 +507,117 @@ deps_write (const cpp_reader *pfile, FILE *fp, unsigned int colmax)
>    make_write (pfile, fp, colmax);
>  }
>  
> +static void
> +p1689r5_write_filepath (const char *name, FILE *fp)

This and the other p1689r5 functions need more comments, at least one at 
the top explaining their purpose.

Jason


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v7 1/4] driver: add a spec function to join arguments
  2023-08-23 19:29   ` [PATCH v7 1/4] driver: " Jason Merrill
@ 2023-08-23 21:29     ` Joseph Myers
  0 siblings, 0 replies; 8+ messages in thread
From: Joseph Myers @ 2023-08-23 21:29 UTC (permalink / raw)
  To: Jason Merrill; +Cc: Ben Boeckel, gcc-patches, brad.king

On Wed, 23 Aug 2023, Jason Merrill via Gcc-patches wrote:

> Joseph, any thoughts on these issues or the workaround?

I don't have any comments here.

-- 
Joseph S. Myers
joseph@codesourcery.com

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2023-08-23 21:30 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-07-02 16:32 [PATCH v7 0/4] P1689R5 support Ben Boeckel
2023-07-02 16:32 ` [PATCH v7 1/4] spec: add a spec function to join arguments Ben Boeckel
2023-08-23 19:29   ` [PATCH v7 1/4] driver: " Jason Merrill
2023-08-23 21:29     ` Joseph Myers
2023-07-02 16:32 ` [PATCH v7 2/4] p1689r5: initial support Ben Boeckel
2023-08-23 19:37   ` Jason Merrill
2023-07-02 16:32 ` [PATCH v7 3/4] c++modules: report imported CMI files as dependencies Ben Boeckel
2023-07-02 16:32 ` [PATCH v7 4/4] c++modules: report module mapper files as a dependency Ben Boeckel

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