[PATCH] D12402: PR24595: clang-cl fails to compile vswriter.h header from Windows SDK 8.1 in 32 bit mode

[Andrey Bokhanko via cfe-commits]

andreybokhanko created this revision.
andreybokhanko added a reviewer: rnk.
andreybokhanko added a subscriber: cfe-commits.

As described in PR24595, clang-cl fails to compile vswriter.h header from Windows SDK 8.1 in 32 bit mode. This patch fixes this.

More on vswriter.h is here: https://msdn.microsoft.com/en-us/library/aa384627(v=vs.85).aspx

I'm not sure adding a new warning is the right approach -- maybe we should downgrade "err_conflicting_overriding_cc_attributes" to a Warning with DefaultError attribute?

http://reviews.llvm.org/D12402

Files:
  include/clang/Basic/DiagnosticSemaKinds.td
  lib/Sema/SemaDeclCXX.cpp
  test/SemaCXX/virtual-override-x86.cpp

Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -12933,9 +12933,16 @@
   if (New->getStorageClass() == SC_Static)
     return false;
 
-  Diag(New->getLocation(),
-       diag::err_conflicting_overriding_cc_attributes)
-    << New->getDeclName() << New->getType() << Old->getType();
+  // vswriter.h header from Windows SDK violates this. Thus, we should just
+  // warn, not error on Windows.
+  if (getLangOpts().MSVCCompat)
+    Diag(New->getLocation(),
+         diag::warn_conflicting_overriding_cc_attributes)
+      << New->getDeclName() << New->getType() << Old->getType();
+  else
+    Diag(New->getLocation(),
+         diag::err_conflicting_overriding_cc_attributes)
+      << New->getDeclName() << New->getType() << Old->getType();
   Diag(Old->getLocation(), diag::note_overridden_virtual_function);
   return true;
 }
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -1403,6 +1403,11 @@
   "virtual function %0 has different calling convention attributes "
   "%diff{($) than the function it overrides (which has calling convention $)|"
   "than the function it overrides}1,2">;
+def warn_conflicting_overriding_cc_attributes : Warning<
+  "virtual function %0 has different calling convention attributes "
+  "%diff{($) than the function it overrides (which has calling convention $)|"
+  "than the function it overrides}1,2. New attribute ignored.">,
+  InGroup<IgnoredAttributes>;
 
 def err_covariant_return_inaccessible_base : Error<
   "invalid covariant return for virtual function: %1 is a "
Index: test/SemaCXX/virtual-override-x86.cpp
===================================================================
--- test/SemaCXX/virtual-override-x86.cpp
+++ test/SemaCXX/virtual-override-x86.cpp
@@ -1,4 +1,7 @@
-// RUN: %clang_cc1 -triple=i686-pc-win32 -fsyntax-only -verify %s -std=c++11
+// RUN: %clang_cc1 -triple=i686-pc-win32 -fsyntax-only -verify %s -std=c++11 -DTEST1
+// RUN: %clang_cc1 -triple=i386-pc-win32 -fms-compatibility -fsyntax-only -verify %s -std=c++11 -DTEST2
+
+#ifdef TEST1
 
 namespace PR14339 {
   class A {
@@ -31,3 +34,23 @@
     void g();  // expected-error{{virtual function 'g' has different calling convention attributes ('void () __attribute__((thiscall))') than the function it overrides (which has calling convention 'void () __attribute__((stdcall))'}}
   };
 }
+
+#elif TEST2
+
+// PR24595: This code is present in vswriter.h header file from Windows SDK 8.1.
+// We should be able to compile it in 32 bit mode.
+class CVssWriter
+{
+public:
+  __stdcall CVssWriter() {}
+  virtual __stdcall ~CVssWriter() {} // expected-note {{overridden virtual function is here}}
+};
+
+class CVssWriterEx : public CVssWriter // expected-warning {{virtual function '~CVssWriterEx' has different calling convention attributes ('void () __attribute__((thiscall))') than the function it overrides (which has calling convention 'void () __attribute__((stdcall)) noexcept'). New attribute ignored.}}
+{};
+
+#else
+
+#error Unknown test
+
+#endif


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