[clang] Mark some language options as benign.

I'm  fairly certain that the options in this CL are benign, as I don't believe they affect the AST.
* RTTI - shouldn't affect the AST, should only affect codegen
* Trivial var init - also should only affect codegen
* Stack protector - also codegen
* Exceptions - Since exceptions do allow new things in the AST, but I'm pretty sure that they can differ in parent and child safely, I marked it as compatible instead.

I welcome any input from someone more familiar with this than me, as I might be wrong.

Author: matts1

clang/docs/ReleaseNotes.rst

@@ -295,6 +295,7 @@ Bug Fixes to C++ Support
 - Clang no longer crashes when a coroutine is declared ``[[noreturn]]``. (#GH127327)
 - Clang now uses the parameter location for abbreviated function templates in ``extern "C"``. (#GH46386)
 - Clang now correctly parses ``if constexpr`` expressions in immediate function context. (#GH123524)
+- Clang modules now allow a module and its user to have a larger variety of configurations.
 
 Improvements to C++ diagnostics
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

clang/include/clang/Basic/LangOptions.def

@@ -139,18 +139,18 @@ ENUM_LANGOPT(AltivecSrcCompat, AltivecSrcCompatKind, 2,
 LANGOPT(ConvergentFunctions, 1, 1, "Assume convergent functions")
 LANGOPT(AltiVec           , 1, 0, "AltiVec-style vector initializers")
 LANGOPT(ZVector           , 1, 0, "System z vector extensions")
-LANGOPT(Exceptions        , 1, 0, "exception handling")
-LANGOPT(ObjCExceptions    , 1, 0, "Objective-C exceptions")
-LANGOPT(CXXExceptions     , 1, 0, "C++ exceptions")
+COMPATIBLE_LANGOPT(Exceptions        , 1, 0, "exception handling")
+COMPATIBLE_LANGOPT(ObjCExceptions    , 1, 0, "Objective-C exceptions")
+COMPATIBLE_LANGOPT(CXXExceptions     , 1, 0, "C++ exceptions")
 LANGOPT(EHAsynch          , 1, 0, "C/C++ EH Asynch exceptions")
 ENUM_LANGOPT(ExceptionHandling, ExceptionHandlingKind, 3,
              ExceptionHandlingKind::None, "exception handling")
 LANGOPT(IgnoreExceptions  , 1, 0, "ignore exceptions")
 LANGOPT(ExternCNoUnwind   , 1, 0, "Assume extern C functions don't unwind")
 LANGOPT(AssumeNothrowExceptionDtor , 1, 0, "Assume exception object's destructor is nothrow")
 LANGOPT(TraditionalCPP    , 1, 0, "traditional CPP emulation")
-LANGOPT(RTTI              , 1, 1, "run-time type information")
-LANGOPT(RTTIData          , 1, 1, "emit run-time type information data")
+BENIGN_LANGOPT(RTTI              , 1, 1, "run-time type information")
+BENIGN_LANGOPT(RTTIData          , 1, 1, "emit run-time type information data")
 LANGOPT(MSBitfields       , 1, 0, "Microsoft-compatible structure layout")
 LANGOPT(MSVolatile        , 1, 0, "Microsoft-compatible volatile loads and stores")
 LANGOPT(Freestanding, 1, 0, "freestanding implementation")
@@ -397,13 +397,13 @@ BENIGN_ENUM_LANGOPT(ExternDeclNoDLLStorageClassVisibility, VisibilityFromDLLStor
 BENIGN_LANGOPT(SemanticInterposition        , 1, 0, "semantic interposition")
 BENIGN_LANGOPT(HalfNoSemanticInterposition, 1, 0,
                "Like -fno-semantic-interposition but don't use local aliases")
-ENUM_LANGOPT(StackProtector, StackProtectorMode, 2, SSPOff,
+BENIGN_ENUM_LANGOPT(StackProtector, StackProtectorMode, 2, SSPOff,
              "stack protector mode")
-ENUM_LANGOPT(TrivialAutoVarInit, TrivialAutoVarInitKind, 2, TrivialAutoVarInitKind::Uninitialized,
+BENIGN_ENUM_LANGOPT(TrivialAutoVarInit, TrivialAutoVarInitKind, 2, TrivialAutoVarInitKind::Uninitialized,
              "trivial automatic variable initialization")
-VALUE_LANGOPT(TrivialAutoVarInitStopAfter, 32, 0,
+BENIGN_VALUE_LANGOPT(TrivialAutoVarInitStopAfter, 32, 0,
              "stop trivial automatic variable initialization after the specified number of instances. Must be greater than 0.")
-VALUE_LANGOPT(TrivialAutoVarInitMaxSize, 32, 0,
+BENIGN_VALUE_LANGOPT(TrivialAutoVarInitMaxSize, 32, 0,
              "stop trivial automatic variable initialization if var size exceeds the specified size (in bytes). Must be greater than 0.")
 ENUM_LANGOPT(SignedOverflowBehavior, SignedOverflowBehaviorTy, 2, SOB_Undefined,
              "signed integer overflow handling")