[clang] [test] Narrow down an MSVC specific behaviour to only not covever MinGW

[mstorsjo]

Summary

This uses the same logic as in c2b256a990590dc8b69930259650cfeb085add03;
we can't check defined(_MSC_VER) invoked as %clang_cc1, therefore
check for !defined(MINGW32) instead.

This fixes the same issue in a new testcase that was added after this
issue was fixed last time in c2b256a990590dc8b69930259650cfeb085add03.

[Endill]

Thank you!
I've asked Aaron what is the best way to check for MSVC-like triple before relanding this test. So today we both learned.

[mstorsjo]

In D151661#4379958, @Endill wrote:

Thank you!
I've asked Aaron what is the best way to check for MSVC-like triple before relanding this test. So today we both learned.

Generally, the canonical way to check for it is #ifdef _MSC_VER - however in the %clang_cc1 tests, it's not automatically defined. This, because the driver heuristically tries to guess a MSVC version to mimic, which it then passes as a version number to clang -cc1 with -fms-compatibility-version or similar. When invoking clang -cc1 manually, this doesn't get set and _MSC_VER is undefined. (I'm considering changing code to make sure that _MSC_VER always is defined in such cases too, even to a dummy version number .)

[Endill]

In D151661#4380060, @mstorsjo wrote:

In D151661#4379958, @Endill wrote:

Thank you!
I've asked Aaron what is the best way to check for MSVC-like triple before relanding this test. So today we both learned.

Generally, the canonical way to check for it is #ifdef _MSC_VER - however in the %clang_cc1 tests, it's not automatically defined. This, because the driver heuristically tries to guess a MSVC version to mimic, which it then passes as a version number to clang -cc1 with -fms-compatibility-version or similar. When invoking clang -cc1 manually, this doesn't get set and _MSC_VER is undefined.

Yes, I remember checking _MSC_VER and _MSC_FULL_VER, but they didn't work.

(I'm considering changing code to make sure that _MSC_VER always is defined in such cases too, even to a dummy version number .)

That would be fantastic for DR and conformance tests!

clang/test/CXX/drs/dr9xx.cpp

#if __cplusplus >= 201103L
   void test() {
     auto lam = [](int x = 42) { return x; };
   }
 #endif
 }
 
 namespace dr977 { // dr977: yes
 enum E { e = E() };
-#ifndef _WIN32
+#if !defined(_WIN32) || defined(__MINGW32__)
 // expected-error@-2 {{invalid use of incomplete type 'E'}}
 // expected-note@-3 {{definition of 'dr977::E' is not complete until the closing '}'}}
 #endif
 #if __cplusplus >= 201103L
 enum E2 : int { e2 = E2() };
 enum struct E3 { e = static_cast<int>(E3()) };
 enum struct E4 : int { e = static_cast<int>(E4()) };
 #endif