[00/32] C++ 20 Modules
Tue Nov 3 21:12:55 GMT 2020
Here is the implementation of C++20 modules that I have been developing
on the devel/c++-modules branch over the last few years.
It is not a complete implementation. The major missing pieces are:
1) Private Module Fragment
The syntax is recognized and a sorry emitted
2) textually parsing a duplicate global module definition when a
definition has already been read from a header-unit. (the converse is
3) Complete type (in)visibility when provided in implementation
partitions that are imported into the primary interface. Users will see
the type as complete.
4) Internal linkage reachability rules from exported entities. We're
likely to accept ill-formed programs. This will not cause us to reject
It is some 25K new lines of code (plus testsuite). There are about 48
FIXMEs, nearly all in module.cc and the remaining in name-lookup.c. Of
these 12 are QOI comments. The remaining 36 probably fall into the
1/3 are repeating a FIXME mentioned elsewhere
1/3 are already resolved, or have become irrelevant
1/3 are defects (an above missing feature, a QOI issue, or something else).
I believe there is time in stage 1 to address the most significant ones.
I have bootstrapped and tested on:
Iain Sandoe has been regularly bootstrapping on x86_64-darwin. Joseph
Myers graciously built for i686-mingw host. We eventually ran into
compilation errors in the analyzer, as it seemed unprepared for an
I have attempted to break the patches apart into coherent pieces. But
they are somewhat interconnected.
01-langhooks.diff New langhooks
02-cpp-line-maps.diff line-map pieces
03-cpp-callbacks.diff Preprocessor callbacks
04-cpp-lexer.diff There are new lexing requirements
05-cpp-files.diff ... and file reading functionality
06-cpp-macro.diff ... and macro expansion rules
07-cpp-main.diff Main file reading
08-cpp-mkdeps.diff Dependency generation
09-core-diag.diff Core diagnostics
11-core-parmtime.diff parameters and time instrumentation
12-core-doc.diff User documentation
13-family-options.diff New options
14-family-keywords.diff New keyword
15-c++-lexer.diff New C++ lexing
16-c++-infra.diff C++ infrastructure interfaces
17-c++-infra-constexpr.diff new constexpr interfacing
18-c++-infra-template.diff new template interfacing
19-global-trees.diff Global tree ordering
20-c++-dynctor.diff Dynamic constructor generation
21-core-rawbits.diff Some core node bits
22-c++-otherbits.diff Miscellaneous C++ changes
24-c++-mapper.diff Module Mapper
25-c++-modules.diff The Modules file
26-c++-name-lookup.diff Name lookup changes
27-c++-parser.diff Parser changes
28-c++-langhooks.diff Lang hooks implementation
29-c++-make.diff Makefile changes
30-test-harness.diff Testharness changes
31-testsuite.diff The testsuite
32-aix-fixincl.diff AIX fixinclude
Nearly all of this is within gcc/cp and libcpp/ directories. There are
a few changes to gcc/ and more changes in gcc/c-family/ It is likely
that this patchset will cause breakages, for that I apologize (please
try the modules branch and report early).
My understanding is that a Global Maintainer's approval is needed for
such a large patchset. It's be good to get this in as early in stage 3
as possible (if stage 1 expires).
Definitely the most important event of today :) But don't forget to vote.
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