From fe91b9d6da99d346abbd1063b1456a30664b215b Mon Sep 17 00:00:00 2001 From: Nico Weber Date: Tue, 20 Aug 2019 16:28:11 +0000 Subject: win: Enable /Zc:twoPhase by default if targeting MSVC 2017 update 3 or newer MSVC 2017 update 3 (_MSC_VER 1911) enables /Zc:twoPhase by default, and so should clang-cl: https://docs.microsoft.com/en-us/cpp/build/reference/zc-twophase clang-cl takes the MSVC version it emulates from the -fmsc-version flag, or if that's not passed it tries to check what the installed version of MSVC is and uses that, and failing that it uses a default version that's currently 1911. So this changes the default if no -fmsc-version flag is passed and no installed MSVC is detected. (It also changes the default if -fmsc-version is passed or MSVC is detected, and either indicates _MSC_VER >= 1911.) As mentioned in the MSDN article, the Windows SDK header files in version 10.0.15063.0 (Creators Update or Redstone 2) and earlier versions do not work correctly with /Zc:twoPhase. If you need to use these old SDKs with a new clang-cl, explicitly pass /Zc:twoPhase- to get the old behavior. Fixes PR43032. Differential Revision: https://reviews.llvm.org/D66394 llvm-svn: 369402 --- clang/lib/Driver/ToolChains/Clang.cpp | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'clang/lib/Driver/ToolChains/Clang.cpp') diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 690d4fa3fa4..c0f914bf989 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -4883,12 +4883,14 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, !IsWindowsMSVC || IsMSVC2015Compatible)) CmdArgs.push_back("-fno-threadsafe-statics"); - // -fno-delayed-template-parsing is default, except when targeting MSVC. - // Many old Windows SDK versions require this to parse. - // FIXME: MSVC introduced /Zc:twoPhase- to disable this behavior in their - // compiler. We should be able to disable this by default at some point. + // -fno-delayed-template-parsing is default, except when targeting MSVC + // earlier than MSVC 2017 15.3 (_MSC_VER 1911). Windows SDK versions + // 10.0.15063.0 (Creators Update or Redstone 2) and earlier require this to + // parse. + bool IsMSVCBefore2017Update3 = !MSVT.empty() && MSVT < VersionTuple(19, 11); if (Args.hasFlag(options::OPT_fdelayed_template_parsing, - options::OPT_fno_delayed_template_parsing, IsWindowsMSVC)) + options::OPT_fno_delayed_template_parsing, + IsMSVCBefore2017Update3)) CmdArgs.push_back("-fdelayed-template-parsing"); // -fgnu-keywords default varies depending on language; only pass if -- cgit v1.2.3