Don't remove __cplusplus

For the indexing we need all tool chain macros. Originally it was a fix
because the C++ version of the project part and __cplusplus could be
different but now they should be the same. They will be now removed in the
compiler options builder.

Change-Id: I7ae8721a29632473e76ecedb411a6c9001e5e199
Task-number: QTCREATORBUG-21265
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/plugins/cpptools/compileroptionsbuilder.cpp

@@ -44,13 +44,15 @@ namespace CppTools {
 CompilerOptionsBuilder::CompilerOptionsBuilder(const ProjectPart &projectPart,
                                                UseSystemHeader useSystemHeader,
                                                SkipBuiltIn skipBuiltInHeaderPathsAndDefines,
+                                               SkipLanguageDefines skipLanguageDefines,
                                                QString clangVersion,
                                                QString clangResourceDirectory)
     : m_projectPart(projectPart)
-    , m_useSystemHeader(useSystemHeader)
     , m_clangVersion(clangVersion)
     , m_clangResourceDirectory(clangResourceDirectory)
+    , m_useSystemHeader(useSystemHeader)
     , m_skipBuiltInHeaderPathsAndDefines(skipBuiltInHeaderPathsAndDefines)
+    , m_skipLanguageDefines(skipLanguageDefines)
 {
 }
 
@@ -601,8 +603,18 @@ bool CompilerOptionsBuilder::excludeDefineDirective(const ProjectExplorer::Macro
 {
     // Avoid setting __cplusplus & co as this might conflict with other command line flags.
     // Clang should set __cplusplus based on -std= and -fms-compatibility-version version.
-    QTC_ASSERT(macro.key != "__cplusplus", return true);
-    QTC_ASSERT(macro.key != "__STDC_VERSION__", return true);
+    static const auto languageDefines = {"__cplusplus",
+                                         "__STDC_VERSION__",
+                                         "_MSC_BUILD",
+                                         "_MSVC_LANG",
+                                         "_MSC_FULL_VER",
+                                         "_MSC_VER"};
+    if (m_skipLanguageDefines == SkipLanguageDefines::Yes
+            && std::find(languageDefines.begin(),
+                         languageDefines.end(),
+                         macro.key) != languageDefines.end()) {
+        return true;
+    }
 
     // Ignore for all compiler toolchains since LLVM has it's own implementation for
     // __has_include(STR) and __has_include_next(STR)

src/plugins/cpptools/compileroptionsbuilder.h

@@ -31,13 +31,19 @@
 
 namespace CppTools {
 
-enum class UseSystemHeader
+enum class UseSystemHeader : char
 {
     Yes,
     No
 };
 
-enum class SkipBuiltIn
+enum class SkipBuiltIn : char
+{
+    Yes,
+    No
+};
+
+enum class SkipLanguageDefines : char
 {
     Yes,
     No
@@ -54,6 +60,7 @@ public:
     CompilerOptionsBuilder(const ProjectPart &projectPart,
                            UseSystemHeader useSystemHeader = UseSystemHeader::No,
                            SkipBuiltIn skipBuiltInHeaderPathsAndDefines = SkipBuiltIn::No,
+                           SkipLanguageDefines skipLanguageDefines = SkipLanguageDefines::Yes,
                            QString clangVersion = QString(),
                            QString clangResourceDirectory = QString());
 
@@ -107,12 +114,13 @@ private:
     void addWrappedQtHeadersIncludePath(QStringList &list);
 
     QStringList m_options;
-    UseSystemHeader m_useSystemHeader;
 
     QString m_clangVersion;
     QString m_clangResourceDirectory;
 
+    UseSystemHeader m_useSystemHeader;
     SkipBuiltIn m_skipBuiltInHeaderPathsAndDefines;
+    SkipLanguageDefines m_skipLanguageDefines;
 };
 
 } // namespace CppTools