Revert r369402 "win: Enable /Zc:twoPhase by default if targeting MSVC 2017 update...

This broke compiling some ASan tests with never versions of MSVC/the Win
SDK, see https://crbug.com/996675

> 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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@369647 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/docs/ReleaseNotes.rst b/docs/ReleaseNotes.rst
index 0585438d75180ac4030595f037f16e7ed271eaf3..f3291137bca1d42e72c0d16b39df48f881f02f16 100644 (file)
--- a/docs/ReleaseNotes.rst
+++ b/docs/ReleaseNotes.rst
@@ -90,9 +90,6 @@ Attribute Changes in Clang
 Windows Support
 ---------------
 
-- clang-cl now defaults to ``/Zc:twoPhase`` if targeting MSVC2017 update 3 or
-  later (``_MSC_VER`` >= 1911). This matches MSVC's behavior. Explicitly pass
-  ``/Zc:twoPhase-`` to restore the old behavior.
 - ...
 
 C Language Changes in Clang

diff --git a/include/clang/Driver/CLCompatOptions.td b/include/clang/Driver/CLCompatOptions.td
index bf5addb8548061fa719589ccff8cae31e5fa5c41..bb51c3aa11d57f850fcc54f042a0645ce8e8b927 100644 (file)
--- a/include/clang/Driver/CLCompatOptions.td
+++ b/include/clang/Driver/CLCompatOptions.td
@@ -235,10 +235,10 @@ def _SLASH_Zc_trigraphs : CLFlag<"Zc:trigraphs">,
 def _SLASH_Zc_trigraphs_off : CLFlag<"Zc:trigraphs-">,
   HelpText<"Disable trigraphs (default)">, Alias<fno_trigraphs>;
 def _SLASH_Zc_twoPhase : CLFlag<"Zc:twoPhase">,
-  HelpText<"Enable two-phase name lookup in templates (default)">,
+  HelpText<"Enable two-phase name lookup in templates">,
   Alias<fno_delayed_template_parsing>;
 def _SLASH_Zc_twoPhase_ : CLFlag<"Zc:twoPhase-">,
-  HelpText<"Disable two-phase name lookup in templates">,
+  HelpText<"Disable two-phase name lookup in templates (default)">,
   Alias<fdelayed_template_parsing>;
 def _SLASH_Z7 : CLFlag<"Z7">,
   HelpText<"Enable CodeView debug information in object files">;

diff --git a/lib/Driver/ToolChains/Clang.cpp b/lib/Driver/ToolChains/Clang.cpp
index c0f914bf9898b0c9afff23caa290da52c9679e02..690d4fa3fa4e89d7d0e043cda75c3c0329520986 100644 (file)
--- a/lib/Driver/ToolChains/Clang.cpp
+++ b/lib/Driver/ToolChains/Clang.cpp
@@ -4883,14 +4883,12 @@ 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
-  // 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);
+  // -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.
   if (Args.hasFlag(options::OPT_fdelayed_template_parsing,
-                   options::OPT_fno_delayed_template_parsing,
-                   IsMSVCBefore2017Update3))
+                   options::OPT_fno_delayed_template_parsing, IsWindowsMSVC))
     CmdArgs.push_back("-fdelayed-template-parsing");
 
   // -fgnu-keywords default varies depending on language; only pass if

diff --git a/test/Driver/cl-options.c b/test/Driver/cl-options.c
index cb3be9ad7ea72ca20e375ae0d7ab41d83fe7ab19..68f08b0c18c647ccb4eee1e3a27b1f0eb7a762ff 100644 (file)
--- a/test/Driver/cl-options.c
+++ b/test/Driver/cl-options.c
@@ -316,19 +316,13 @@
 
 // We recognize -f[no-]delayed-template-parsing.
 // /Zc:twoPhase[-] has the opposite meaning.
-// RUN: %clang_cl -c -fmsc-version=1910 -### -- %s 2>&1 | FileCheck -check-prefix=OLDDELAYEDDEFAULT %s
-// OLDDELAYEDDEFAULT: "-fdelayed-template-parsing"
-// RUN: %clang_cl -fmsc-version=1911 -c -### -- %s 2>&1 | FileCheck -check-prefix=NEWDELAYEDDEFAULT %s
-// NEWDELAYEDDEFAULT-NOT: "-fdelayed-template-parsing"
-// RUN: %clang_cl -c -fmsc-version=1910 -fdelayed-template-parsing -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDON %s
-// RUN: %clang_cl -c -fmsc-version=1911 -fdelayed-template-parsing -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDON %s
-// RUN: %clang_cl -c -fmsc-version=1910 /Zc:twoPhase- -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDON %s
-// RUN: %clang_cl -c -fmsc-version=1911 /Zc:twoPhase- -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDON %s
+// RUN: %clang_cl -c -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDDEFAULT %s
+// DELAYEDDEFAULT: "-fdelayed-template-parsing"
+// RUN: %clang_cl -c -fdelayed-template-parsing -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDON %s
+// RUN: %clang_cl -c /Zc:twoPhase- -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDON %s
 // DELAYEDON: "-fdelayed-template-parsing"
-// RUN: %clang_cl -c -fmsc-version=1910 -fno-delayed-template-parsing -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDOFF %s
-// RUN: %clang_cl -c -fmsc-version=1911 -fno-delayed-template-parsing -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDOFF %s
-// RUN: %clang_cl -c -fmsc-version=1910 /Zc:twoPhase -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDOFF %s
-// RUN: %clang_cl -c -fmsc-version=1911 /Zc:twoPhase -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDOFF %s
+// RUN: %clang_cl -c -fno-delayed-template-parsing -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDOFF %s
+// RUN: %clang_cl -c /Zc:twoPhase -### -- %s 2>&1 | FileCheck -check-prefix=DELAYEDOFF %s
 // DELAYEDOFF-NOT: "-fdelayed-template-parsing"
 
 // RUN: %clang_cl -c -### /std:c++latest -- %s 2>&1 | FileCheck -check-prefix CHECK-LATEST-CHAR8_T %s