On Fri, 15 Dec 2023 08:08:10 GMT, Julian Waters <jwat...@openjdk.org> wrote:
>> Implementation of [JEP draft: Compile the JDK as >> C++17](https://bugs.openjdk.org/browse/JDK-8310260) > > Julian Waters has updated the pull request with a new target base due to a > merge or a rebase. The incremental webrev excludes the unrelated changes > brought in by the merge/rebase. The pull request contains five additional > commits since the last revision: > > - Merge branch 'openjdk:master' into patch-7 > - Revert vm_version_linux_riscv.cpp > - vm_version_linux_riscv.cpp > - allocation.cpp > - 8310260 In conjunction with changing to C++17, I suggest the following changes to the minimum compiler versions, as indicated in make/autoconf/toolchain.m4 old: make/autoconf/toolchain.m4 TOOLCHAIN_MINIMUM_VERSION_clang="3.5" TOOLCHAIN_MINIMUM_VERSION_gcc="6.0" TOOLCHAIN_MINIMUM_VERSION_microsoft="19.28.0.0" # VS2019 16.8, aka MSVC 14.28 TOOLCHAIN_MINIMUM_VERSION_xlc="16.1.0.0011" proposed new: TOOLCHAIN_MINIMUM_VERSION_clang="13.0" TOOLCHAIN_MINIMUM_VERSION_gcc="9.0" TOOLCHAIN_MINIMUM_VERSION_microsoft="19.28.0.0" # VS2019 16.8, aka MSVC 14.28 TOOLCHAIN_MINIMUM_VERSION_xlc="17.1.1.4" Here's the rationale for each of these: ----- gcc: https://gcc.gnu.org/gcc-9/changes.html "The C++17 implementation is no longer experimental." ----- open xl c++ for aix https://www.ibm.com/docs/en/openxl-c-and-cpp-aix/17.1.1?topic=features-supported-language-levels supports C17 and C++17, with experimental support for C++20 17.1.0 docs explicitly says __clang_version__ is 13.0.0, with the other version macros set accordingly. 17.1.1 just describes the version macros, but doesn't say what their values are. But the __VERSION__ macro description includes "Clang 15.0.0" in the string. Note that there is now a 17.1.2 version, but the aix-ppc porters haven't proposed going that far. ----- Visual Studio https://learn.microsoft.com/en-gb/cpp/overview/visual-cpp-language-conformance?view=msvc-170 We already require VS2019 16.8, which covers all of C++17 features listed on that page. ----- clang https://clang.llvm.org/cxx_status.html c++17 - Clang 5 However, there is a critical bug for which we really want a fix. Using [[noreturn]] seems to be buggy and leads to crashes. This has been seen with clang 12. It appears to be fixed with clang 13.0.0 (Xcode 13.0). There may also be a bug somewhere in the 13.x release series with the handling of noexcept. See discussion in https://bugs.openjdk.org/browse/JDK-8255082. Oracle is currently using Xcode 14.3.1 (clang 14.0.3), so I think we wouldn't object to something between 13.0.0 and 14.0.3 as the minimum version. ------------- PR Comment: https://git.openjdk.org/jdk/pull/14988#issuecomment-1858097523
