r369647 - Revert r369402 "win: Enable /Zc:twoPhase by default if targeting MSVC 2017 update 3 or newer"

Hans Wennborg via cfe-commits cfe-commits at lists.llvm.org
Thu Aug 22 06:15:36 PDT 2019


Author: hans
Date: Thu Aug 22 06:15:36 2019
New Revision: 369647

URL: http://llvm.org/viewvc/llvm-project?rev=369647&view=rev
Log:
Revert r369402 "win: Enable /Zc:twoPhase by default if targeting MSVC 2017 update 3 or newer"

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

Modified:
    cfe/trunk/docs/ReleaseNotes.rst
    cfe/trunk/include/clang/Driver/CLCompatOptions.td
    cfe/trunk/lib/Driver/ToolChains/Clang.cpp
    cfe/trunk/test/Driver/cl-options.c

Modified: cfe/trunk/docs/ReleaseNotes.rst
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/docs/ReleaseNotes.rst?rev=369647&r1=369646&r2=369647&view=diff
==============================================================================
--- cfe/trunk/docs/ReleaseNotes.rst (original)
+++ cfe/trunk/docs/ReleaseNotes.rst Thu Aug 22 06:15:36 2019
@@ -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

Modified: cfe/trunk/include/clang/Driver/CLCompatOptions.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/CLCompatOptions.td?rev=369647&r1=369646&r2=369647&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/CLCompatOptions.td (original)
+++ cfe/trunk/include/clang/Driver/CLCompatOptions.td Thu Aug 22 06:15:36 2019
@@ -235,10 +235,10 @@ def _SLASH_Zc_trigraphs : CLFlag<"Zc:tri
 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">;

Modified: cfe/trunk/lib/Driver/ToolChains/Clang.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/ToolChains/Clang.cpp?rev=369647&r1=369646&r2=369647&view=diff
==============================================================================
--- cfe/trunk/lib/Driver/ToolChains/Clang.cpp (original)
+++ cfe/trunk/lib/Driver/ToolChains/Clang.cpp Thu Aug 22 06:15:36 2019
@@ -4883,14 +4883,12 @@ void Clang::ConstructJob(Compilation &C,
                     !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

Modified: cfe/trunk/test/Driver/cl-options.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/cl-options.c?rev=369647&r1=369646&r2=369647&view=diff
==============================================================================
--- cfe/trunk/test/Driver/cl-options.c (original)
+++ cfe/trunk/test/Driver/cl-options.c Thu Aug 22 06:15:36 2019
@@ -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




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