Clang: Enable exceptions explicitly

For some reason, clang 3.8.0 on Windows does not enable exceptions anymore,
which leads to parse errors in MSVC headers (reported upstream [1]).

With this change, we can finally parse main/mainwindow.cpp of a Qt Widgets
Application for a MSVC2015 Kit and libclang 3.8.0 without any error.

[1] https://llvm.org/bugs/show_bug.cgi?id=27324

Change-Id: I532ad4852a06318baf083d363378bc577b3c4309
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>

src/plugins/clangcodemodel/clangutils.cpp

@@ -91,6 +91,7 @@ public:
         optionsBuilder.addTargetTriple();
         optionsBuilder.addLanguageOption(fileKind);
         optionsBuilder.addOptionsForLanguage(/*checkForBorlandExtensions*/ true);
+        optionsBuilder.enableExceptions();
 
         optionsBuilder.addToolchainAndProjectDefines();
         optionsBuilder.undefineCppLanguageFeatureMacrosForMsvc2015();

src/plugins/clangstaticanalyzer/clangstaticanalyzerruncontrol.cpp

@@ -169,6 +169,7 @@ public:
         optionsBuilder.addTargetTriple();
         optionsBuilder.addLanguageOption(fileKind);
         optionsBuilder.addOptionsForLanguage(false);
+        optionsBuilder.enableExceptions();
 
         // In gcc headers, lots of built-ins are referenced that clang does not understand.
         // Therefore, prevent the inclusion of the header that references them. Of course, this
@@ -184,9 +185,7 @@ public:
         optionsBuilder.addHeaderPathOptions();
         optionsBuilder.addMsvcCompatibilityVersion();
 
-        if (type == ProjectExplorer::Constants::MSVC_TOOLCHAIN_TYPEID)
-            optionsBuilder.add(QLatin1String("/EHsc")); // clang-cl does not understand exceptions
-        else
+        if (type != ProjectExplorer::Constants::MSVC_TOOLCHAIN_TYPEID)
             optionsBuilder.add(QLatin1String("-fPIC")); // TODO: Remove?
 
         QStringList options = optionsBuilder.options();
@@ -240,6 +239,14 @@ private:
         return CompilerOptionsBuilder::defineOption();
     }
 
+    void enableExceptions() override
+    {
+        if (m_isMsvcToolchain)
+            add(QLatin1String("/EHsc"));
+        else
+            CompilerOptionsBuilder::enableExceptions();
+    }
+
 private:
     bool m_isMsvcToolchain;
 };

src/plugins/cpptools/compileroptionsbuilder.cpp

@@ -92,6 +92,12 @@ void CompilerOptionsBuilder::addTargetTriple()
     }
 }
 
+void CompilerOptionsBuilder::enableExceptions()
+{
+    add(QLatin1String("-fcxx-exceptions"));
+    add(QLatin1String("-fexceptions"));
+}
+
 void CompilerOptionsBuilder::addHeaderPathOptions()
 {
     typedef ProjectPartHeaderPath HeaderPath;

src/plugins/cpptools/compileroptionsbuilder.h

@@ -46,6 +46,7 @@ public:
 
     // Add options based on project part
     virtual void addTargetTriple();
+    virtual void enableExceptions();
     void addHeaderPathOptions();
     void addToolchainAndProjectDefines();
     virtual void addLanguageOption(ProjectFile::Kind fileKind);