Revert "Clang: Stop enabling exceptions explicitly"

This reverts commit b114f77d8a633341b617a5cadd04e5977beae65d as
"--driver-mode=cl" apparently still disables exceptions.

Task-number: QTCREATORBUG-23000
Change-Id: I9c49d971fafda5e1aca8445f8921e50f323d368f
Reviewed-by: Cristian Adam <cristian.adam@qt.io>

2 files changed, 13 insertions, 0 deletions

diff --git a/src/plugins/cpptools/compileroptionsbuilder.cpp b/src/plugins/cpptools/compileroptionsbuilder.cpp
index ee534757ea1..3804c3feb26 100644
--- a/src/plugins/cpptools/compileroptionsbuilder.cpp
+++ b/src/plugins/cpptools/compileroptionsbuilder.cpp
@@ -136,6 +136,7 @@ QStringList CompilerOptionsBuilder::build(ProjectFile::Kind fileKind,
     addTargetTriple();
     updateFileLanguage(fileKind);
     addLanguageVersionAndExtensions();
+    enableExceptions();
 
     addPrecompiledHeaderOptions(usePrecompiledHeaders);
     addProjectConfigFileInclude();
@@ -270,6 +271,17 @@ void CompilerOptionsBuilder::addCompilerFlags()
     add(m_compilerFlags.flags);
 }
 
+void CompilerOptionsBuilder::enableExceptions()
+{
+    // With "--driver-mode=cl" exceptions are disabled (clang 8).
+    // This is most likely due to incomplete exception support of clang.
+    // However, as we need exception support only in the frontend,
+    // enabling them explicitly should be fine.
+    if (m_projectPart.languageVersion > ::Utils::LanguageVersion::LatestC)
+        add("-fcxx-exceptions");
+    add("-fexceptions");
+}
+
 static QString creatorResourcePath()
 {
 #ifndef UNIT_TESTS
diff --git a/src/plugins/cpptools/compileroptionsbuilder.h b/src/plugins/cpptools/compileroptionsbuilder.h
index 5b7c682407e..b2c8313771e 100644
--- a/src/plugins/cpptools/compileroptionsbuilder.h
+++ b/src/plugins/cpptools/compileroptionsbuilder.h
@@ -69,6 +69,7 @@ public:
     void addExtraCodeModelFlags();
     void addPicIfCompilerFlagsContainsIt();
     void addCompilerFlags();
+    void enableExceptions();
     void insertWrappedQtHeaders();
     void addLanguageVersionAndExtensions();
     void updateFileLanguage(ProjectFile::Kind fileKind);