diff options
Diffstat (limited to 'libbuild2/cxx/init.cxx')
| -rw-r--r-- | libbuild2/cxx/init.cxx | 39 |
1 files changed, 19 insertions, 20 deletions
diff --git a/libbuild2/cxx/init.cxx b/libbuild2/cxx/init.cxx index 626c795..8a2ad88 100644 --- a/libbuild2/cxx/init.cxx +++ b/libbuild2/cxx/init.cxx @@ -388,28 +388,24 @@ namespace build2 { case compiler_type::msvc: { - // While modules are supported in VC 15.0 (19.10), there is a - // bug in the separate interface/implementation unit support - // which makes them pretty much unusable. This has been fixed in - // 15.3 (19.11). And 15.5 (19.12) supports the `export module - // M;` syntax. And 16.4 (19.24) supports the global module - // fragment. And in 16.8 all the modules-related options have - // been changed. Seeing that the whole thing is unusable anyway, - // we disable it for 16.8 or later for now. + // Modules are enabled by default in /std:c++20 and + // /std:c++latest with both defining __cpp_modules to 201907 + // (final C++20 module), at least as of 17.6 (LTS). // - if ((mj > 19 || (mj == 19 && mi >= (modules.value ? 10 : 12))) && - (mj < 19 || (mj == 19 && mi < 28) || modules.value)) + // @@ Should we enable modules by default? + // + if (modules.value) { - prepend ( - mj > 19 || mi >= 24 ? - "/D__cpp_modules=201810" : // p1103 (merged modules) - mj == 19 || mi >= 12 ? - "/D__cpp_modules=201704" : // p0629r0 (export module M;) - "/D__cpp_modules=201703"); // n4647 ( module M;) - - prepend ("/experimental:module"); + if (mj < 19 || (mj == 19 && mi < 36)) + { + fail << "support for C++ modules requires MSVC 17.6 or later" << + info << "C++ compiler is " << ci.signature << + info << "required by " << project (rs) << '@' << rs; + } + modules = true; } + break; } case compiler_type::gcc: @@ -419,6 +415,10 @@ namespace build2 // generated headers via the mapper, we require the user to // explicitly request modules. // + // @@ Actually, now that we pre-generate headers by default, + // this is probably no longer the reason. But GCC modules being + // unusable due to bugs is a reason enough. + // if (mj >= 11 && modules.value) { // Defines __cpp_modules: @@ -870,8 +870,7 @@ namespace build2 "cxx.link", "cxx.install", - cm.x_info->id.type, - cm.x_info->id.variant, + cm.x_info->id, cm.x_info->class_, cm.x_info->version.major, cm.x_info->version.minor, |