[MSVC Compat] Implement -EHc semantics
The -EHc flag implicitly adds a nothrow attribute to any extern "C"
function when exceptions are enabled.
llvm-svn: 261425
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 9c64da5..fd647a4 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -5786,8 +5786,7 @@
/// - s: Cleanup after "synchronous" exceptions, aka C++ exceptions.
/// - a: Cleanup after "asynchronous" exceptions, aka structured exceptions.
/// The 'a' modifier is unimplemented and fundamentally hard in LLVM IR.
-/// - c: Assume that extern "C" functions are implicitly noexcept. This
-/// modifier is an optimization, so we ignore it for now.
+/// - c: Assume that extern "C" functions are implicitly nounwind.
/// The default is /EHs-c-, meaning cleanups are disabled.
static EHFlags parseClangCLEHFlags(const Driver &D, const ArgList &Args) {
EHFlags EH;
@@ -5897,10 +5896,11 @@
const Driver &D = getToolChain().getDriver();
EHFlags EH = parseClangCLEHFlags(D, Args);
- // FIXME: Do something with NoExceptC.
if (EH.Synch || EH.Asynch) {
CmdArgs.push_back("-fcxx-exceptions");
CmdArgs.push_back("-fexceptions");
+ if (EH.NoUnwindC)
+ CmdArgs.push_back("-fexternc-nounwind");
}
// /EP should expand to -E -P.