Clang: Add conditions for adding exceptions flag

For GCC it can be deduced from the compiler flags, so no correction is
needed.

For MSVC it can be deduced from the detected defines.

Amends 26693e8212.

Change-Id: Ie4850f328a2afdb3e5158c58f8c30a2644d9c592
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/cpptools/compileroptionsbuilder.cpp

@@ -35,6 +35,7 @@
 #include <projectexplorer/projectexplorerconstants.h>
 #include <projectexplorer/projectmacro.h>
 
+#include <utils/algorithm.h>
 #include <utils/cpplanguage_details.h>
 #include <utils/fileutils.h>
 #include <utils/qtcassert.h>
@@ -137,7 +138,7 @@ QStringList CompilerOptionsBuilder::build(ProjectFile::Kind fileKind,
     addTargetTriple();
     updateFileLanguage(fileKind);
     addLanguageVersionAndExtensions();
-    enableExceptions();
+    addMsvcExceptions();
 
     addPrecompiledHeaderOptions(usePrecompiledHeaders);
     addProjectConfigFileInclude();
@@ -273,6 +274,17 @@ void CompilerOptionsBuilder::addCompilerFlags()
     add(m_compilerFlags.flags);
 }
 
+void CompilerOptionsBuilder::addMsvcExceptions()
+{
+    if (!m_clStyle)
+        return;
+    if (Utils::anyOf(m_projectPart.toolChainMacros, [](const ProjectExplorer::Macro &macro) {
+        return macro.key == "_CPPUNWIND";
+    })) {
+        enableExceptions();
+    }
+}
+
 void CompilerOptionsBuilder::enableExceptions()
 {
     // With "--driver-mode=cl" exceptions are disabled (clang 8).

src/plugins/cpptools/compileroptionsbuilder.h

@@ -69,6 +69,7 @@ public:
     void addExtraCodeModelFlags();
     void addPicIfCompilerFlagsContainsIt();
     void addCompilerFlags();
+    void addMsvcExceptions();
     void enableExceptions();
     void insertWrappedQtHeaders();
     void insertWrappedMingwHeaders();

tests/unit/unittest/compileroptionsbuilder-test.cpp

@@ -650,8 +650,6 @@ TEST_F(CompilerOptionsBuilder, BuildAllOptions)
                             "-x",
                             "c++",
                             "-std=c++17",
-                            "-fcxx-exceptions",
-                            "-fexceptions",
                             "-DprojectFoo=projectBar",
                             "-I", IsPartOfHeader("wrappedQtHeaders"),
                             "-I", IsPartOfHeader(toNative("wrappedQtHeaders/QtCore").toStdString()),
@@ -674,6 +672,44 @@ TEST_F(CompilerOptionsBuilder, BuildAllOptionsCl)
 
     compilerOptionsBuilder.build(ProjectFile::CXXSource, CppTools::UsePrecompiledHeaders::No);
 
+    ASSERT_THAT(compilerOptionsBuilder.options(),
+                ElementsAre("-nostdinc",
+                            "-nostdinc++",
+                            "--driver-mode=cl",
+                            "/Zs",
+                            "-m64",
+                            "--target=x86_64-apple-darwin10",
+                            "/TP",
+                            "/std:c++17",
+                            "-fms-compatibility-version=19.00",
+                            "-DprojectFoo=projectBar",
+                            "-D__FUNCSIG__=\"\"",
+                            "-D__FUNCTION__=\"\"",
+                            "-D__FUNCDNAME__=\"\"",
+                            "-I", IsPartOfHeader("wrappedQtHeaders"),
+                            "-I", IsPartOfHeader(toNative("wrappedQtHeaders/QtCore").toStdString()),
+                            "-I", toNative("/tmp/path"),
+                            "-I", toNative("/tmp/system_path"),
+                            "/clang:-isystem",
+                            "/clang:" + toNative(CLANG_RESOURCE_DIR ""),
+                            "/clang:-isystem",
+                            "/clang:" + toNative("/tmp/builtin_path")));
+}
+
+TEST_F(CompilerOptionsBuilder, BuildAllOptionsClWithExceptions)
+{
+    projectPart.toolchainType = ProjectExplorer::Constants::MSVC_TOOLCHAIN_TYPEID;
+    projectPart.toolChainMacros.append(ProjectExplorer::Macro{"_CPPUNWIND", "1"});
+    CppTools::CompilerOptionsBuilder compilerOptionsBuilder(projectPart,
+                                                            CppTools::UseSystemHeader::No,
+                                                            CppTools::UseTweakedHeaderPaths::Yes,
+                                                            CppTools::UseLanguageDefines::No,
+                                                            CppTools::UseBuildSystemWarnings::No,
+                                                            "dummy_version",
+                                                            "");
+
+    compilerOptionsBuilder.build(ProjectFile::CXXSource, CppTools::UsePrecompiledHeaders::No);
+
     ASSERT_THAT(compilerOptionsBuilder.options(),
                 ElementsAre("-nostdinc",
                             "-nostdinc++",