Driver/Obj-C: Be compatible with GCC behavior in that -fno-exceptions *does not*

disable Obj-C exceptions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@127836 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Driver/Tools.cpp

@@ -843,25 +843,16 @@ static void addExceptionArgs(const ArgList &Args, types::ID InputType,
   if (ExceptionsEnabled && DidHaveExplicitExceptionFlag)
     ShouldUseExceptionTables = true;
 
-  if (types::isObjC(InputType)) {
-    bool ObjCExceptionsEnabled = ExceptionsEnabled;
+  // Obj-C exceptions are enabled by default, regardless of -fexceptions. This
+  // is not necessarily sensible, but follows GCC.
+  if (types::isObjC(InputType) &&
+      Args.hasFlag(options::OPT_fobjc_exceptions, 
+                   options::OPT_fno_objc_exceptions,
+                   true)) {
+    CmdArgs.push_back("-fobjc-exceptions");
 
-    if (Arg *A = Args.getLastArg(options::OPT_fobjc_exceptions, 
-                                 options::OPT_fno_objc_exceptions,
-                                 options::OPT_fexceptions,
-                                 options::OPT_fno_exceptions)) {
-      if (A->getOption().matches(options::OPT_fobjc_exceptions))
-        ObjCExceptionsEnabled = true;
-      else if (A->getOption().matches(options::OPT_fno_objc_exceptions))
-        ObjCExceptionsEnabled = false;
-    }
-
-    if (ObjCExceptionsEnabled) {
-      CmdArgs.push_back("-fobjc-exceptions");
-
-      ShouldUseExceptionTables |= 
-        shouldUseExceptionTablesForObjCExceptions(Args, Triple);
-    }
+    ShouldUseExceptionTables |= 
+      shouldUseExceptionTablesForObjCExceptions(Args, Triple);
   }
 
   if (types::isCXX(InputType)) {

test/Driver/exceptions.m

@@ -0,0 +1,19 @@
+// RUN: %clang -ccc-host-triple x86_64-apple-darwin9 \
+// RUN:   -fsyntax-only -fno-exceptions %s
+
+void f1() {
+  @throw @"A";
+}
+
+void f0() {
+  @try {
+    f1();
+  } @catch (id x) {
+    ;
+  }
+}
+
+int main() {
+  f0();
+  return 0;
+}