[clang] Move ExceptionHandling from LangOptions to CodeGenOptions (#148982)

jansvoboda11 · web-flow · commit 76058c090714 · 2025-07-16T07:11:13.000-07:00
This PR removes the command line parsing workaround introduced in llvm/llvm-project#146342 by moving `LangOptions::ExceptionHandling` to `CodeGenOptions` that get parsed even for IR input. Additionally, this improves layering, where the codegen library now checks `CodeGenOptions` instead of `LangOptions` for exception handling. (This got enabled by llvm/llvm-project#146422.)
diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def
@@ -56,6 +56,8 @@ CODEGENOPT(XCOFFReadOnlyPointers, 1, 0, Benign) ///< Set for -mxcoff-roptr.
 CODEGENOPT(AllTocData, 1, 0, Benign) ///< AIX -mtocdata
 ENUM_CODEGENOPT(FramePointer, FramePointerKind, 2, FramePointerKind::None, Benign) /// frame-pointer: all,non-leaf,reserved,none
 
+ENUM_CODEGENOPT(ExceptionHandling, ExceptionHandlingKind, 3, ExceptionHandlingKind::None, NotCompatible)
+
 CODEGENOPT(ClearASTBeforeBackend , 1, 0, Benign) ///< Free the AST before running backend code generation. Only works with -disable-free.
 CODEGENOPT(DisableFree       , 1, 0, Benign) ///< Don't free memory.
 CODEGENOPT(DiscardValueNames , 1, 0, Benign) ///< Discard Value Names from the IR (LLVMContext flag)
diff --git a/clang/include/clang/Basic/CodeGenOptions.h b/clang/include/clang/Basic/CodeGenOptions.h
@@ -176,6 +176,9 @@ class CodeGenOptions : public CodeGenOptionsBase {
     llvm_unreachable("invalid FramePointerKind");
   }
 
+  /// Possible exception handling behavior.
+  enum class ExceptionHandlingKind { None, SjLj, WinEH, DwarfCFI, Wasm };
+
   enum class SwiftAsyncFramePointerKind {
     Auto, // Choose Swift async extended frame info based on deployment target.
     Always, // Unconditionally emit Swift async extended frame info.
@@ -552,6 +555,22 @@ class CodeGenOptions : public CodeGenOptionsBase {
     return NoBuiltinFuncs;
   }
 
+  bool hasSjLjExceptions() const {
+    return getExceptionHandling() == ExceptionHandlingKind::SjLj;
+  }
+
+  bool hasSEHExceptions() const {
+    return getExceptionHandling() == ExceptionHandlingKind::WinEH;
+  }
+
+  bool hasDWARFExceptions() const {
+    return getExceptionHandling() == ExceptionHandlingKind::DwarfCFI;
+  }
+
+  bool hasWasmExceptions() const {
+    return getExceptionHandling() == ExceptionHandlingKind::Wasm;
+  }
+
   /// Check if Clang profile instrumenation is on.
   bool hasProfileClangInstr() const {
     return getProfileInstr() ==
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
@@ -98,8 +98,6 @@ LANGOPT(Exceptions        , 1, 0, NotCompatible, "exception handling")
 LANGOPT(ObjCExceptions    , 1, 0, NotCompatible, "Objective-C exceptions")
 LANGOPT(CXXExceptions     , 1, 0, NotCompatible, "C++ exceptions")
 LANGOPT(EHAsynch          , 1, 0, NotCompatible, "C/C++ EH Asynch exceptions")
-ENUM_LANGOPT(ExceptionHandling, ExceptionHandlingKind, 3,
-             ExceptionHandlingKind::None,  NotCompatible, "exception handling")
 LANGOPT(IgnoreExceptions  , 1, 0, NotCompatible, "ignore exceptions")
 LANGOPT(ExternCNoUnwind   , 1, 0, NotCompatible, "Assume extern C functions don't unwind")
 LANGOPT(AssumeNothrowExceptionDtor , 1, 0, NotCompatible, "Assume exception object's destructor is nothrow")
diff --git a/clang/include/clang/Basic/LangOptions.h b/clang/include/clang/Basic/LangOptions.h
@@ -337,9 +337,6 @@ class LangOptionsBase {
 
   enum ExcessPrecisionKind { FPP_Standard, FPP_Fast, FPP_None };
 
-  /// Possible exception handling behavior.
-  enum class ExceptionHandlingKind { None, SjLj, WinEH, DwarfCFI, Wasm };
-
   enum class LaxVectorConversionKind {
     /// Permit no implicit vector bitcasts.
     None,
@@ -788,22 +785,6 @@ class LangOptions : public LangOptionsBase {
     return getSignReturnAddressScope() == SignReturnAddressScopeKind::All;
   }
 
-  bool hasSjLjExceptions() const {
-    return getExceptionHandling() == ExceptionHandlingKind::SjLj;
-  }
-
-  bool hasSEHExceptions() const {
-    return getExceptionHandling() == ExceptionHandlingKind::WinEH;
-  }
-
-  bool hasDWARFExceptions() const {
-    return getExceptionHandling() == ExceptionHandlingKind::DwarfCFI;
-  }
-
-  bool hasWasmExceptions() const {
-    return getExceptionHandling() == ExceptionHandlingKind::Wasm;
-  }
-
   bool isSYCL() const { return SYCLIsDevice || SYCLIsHost; }
 
   bool hasDefaultVisibilityExportMapping() const {
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
@@ -2176,10 +2176,10 @@ def fwasm_exceptions : Flag<["-"], "fwasm-exceptions">, Group<f_Group>,
   HelpText<"Use WebAssembly style exceptions">;
 def exception_model : Separate<["-"], "exception-model">,
   Visibility<[CC1Option]>, HelpText<"The exception model">,
-  Values<"dwarf,sjlj,seh,wasm">,
-  NormalizedValuesScope<"LangOptions::ExceptionHandlingKind">,
-  NormalizedValues<["DwarfCFI", "SjLj", "WinEH", "Wasm"]>,
-  MarshallingInfoEnum<LangOpts<"ExceptionHandling">, "None">;
+  Values<"dwarf,sjlj,seh,wasm,none">,
+  NormalizedValuesScope<"CodeGenOptions::ExceptionHandlingKind">,
+  NormalizedValues<["DwarfCFI", "SjLj", "WinEH", "Wasm", "None"]>,
+  MarshallingInfoEnum<CodeGenOpts<"ExceptionHandling">, "None">;
 def exception_model_EQ : Joined<["-"], "exception-model=">,
   Visibility<[CC1Option]>, Alias<exception_model>;
 def fignore_exceptions : Flag<["-"], "fignore-exceptions">, Group<f_Group>,
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
@@ -407,13 +407,13 @@ static bool initTargetOptions(const CompilerInstance &CI,
   // Set EABI version.
   Options.EABIVersion = TargetOpts.EABIVersion;
 
-  if (LangOpts.hasSjLjExceptions())
+  if (CodeGenOpts.hasSjLjExceptions())
     Options.ExceptionModel = llvm::ExceptionHandling::SjLj;
-  if (LangOpts.hasSEHExceptions())
+  if (CodeGenOpts.hasSEHExceptions())
     Options.ExceptionModel = llvm::ExceptionHandling::WinEH;
-  if (LangOpts.hasDWARFExceptions())
+  if (CodeGenOpts.hasDWARFExceptions())
     Options.ExceptionModel = llvm::ExceptionHandling::DwarfCFI;
-  if (LangOpts.hasWasmExceptions())
+  if (CodeGenOpts.hasWasmExceptions())
     Options.ExceptionModel = llvm::ExceptionHandling::Wasm;
 
   Options.NoInfsFPMath = LangOpts.NoHonorInfs;
diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
@@ -131,28 +131,29 @@ const EHPersonality EHPersonality::ZOS_CPlusPlus = {"__zos_cxx_personality_v2",
                                                     nullptr};
 
 static const EHPersonality &getCPersonality(const TargetInfo &Target,
-                                            const LangOptions &L) {
+                                            const CodeGenOptions &CGOpts) {
   const llvm::Triple &T = Target.getTriple();
   if (T.isWindowsMSVCEnvironment())
     return EHPersonality::MSVC_CxxFrameHandler3;
-  if (L.hasSjLjExceptions())
+  if (CGOpts.hasSjLjExceptions())
     return EHPersonality::GNU_C_SJLJ;
-  if (L.hasDWARFExceptions())
+  if (CGOpts.hasDWARFExceptions())
     return EHPersonality::GNU_C;
-  if (L.hasSEHExceptions())
+  if (CGOpts.hasSEHExceptions())
     return EHPersonality::GNU_C_SEH;
   return EHPersonality::GNU_C;
 }
 
 static const EHPersonality &getObjCPersonality(const TargetInfo &Target,
+                                               const CodeGenOptions &CGOpts,
                                                const LangOptions &L) {
   const llvm::Triple &T = Target.getTriple();
   if (T.isWindowsMSVCEnvironment())
     return EHPersonality::MSVC_CxxFrameHandler3;
 
   switch (L.ObjCRuntime.getKind()) {
   case ObjCRuntime::FragileMacOSX:
-    return getCPersonality(Target, L);
+    return getCPersonality(Target, CGOpts);
   case ObjCRuntime::MacOSX:
   case ObjCRuntime::iOS:
   case ObjCRuntime::WatchOS:
@@ -165,29 +166,29 @@ static const EHPersonality &getObjCPersonality(const TargetInfo &Target,
     [[fallthrough]];
   case ObjCRuntime::GCC:
   case ObjCRuntime::ObjFW:
-    if (L.hasSjLjExceptions())
+    if (CGOpts.hasSjLjExceptions())
       return EHPersonality::GNU_ObjC_SJLJ;
-    if (L.hasSEHExceptions())
+    if (CGOpts.hasSEHExceptions())
       return EHPersonality::GNU_ObjC_SEH;
     return EHPersonality::GNU_ObjC;
   }
   llvm_unreachable("bad runtime kind");
 }
 
 static const EHPersonality &getCXXPersonality(const TargetInfo &Target,
-                                              const LangOptions &L) {
+                                              const CodeGenOptions &CGOpts) {
   const llvm::Triple &T = Target.getTriple();
   if (T.isWindowsMSVCEnvironment())
     return EHPersonality::MSVC_CxxFrameHandler3;
   if (T.isOSAIX())
     return EHPersonality::XL_CPlusPlus;
-  if (L.hasSjLjExceptions())
+  if (CGOpts.hasSjLjExceptions())
     return EHPersonality::GNU_CPlusPlus_SJLJ;
-  if (L.hasDWARFExceptions())
+  if (CGOpts.hasDWARFExceptions())
     return EHPersonality::GNU_CPlusPlus;
-  if (L.hasSEHExceptions())
+  if (CGOpts.hasSEHExceptions())
     return EHPersonality::GNU_CPlusPlus_SEH;
-  if (L.hasWasmExceptions())
+  if (CGOpts.hasWasmExceptions())
     return EHPersonality::GNU_Wasm_CPlusPlus;
   if (T.isOSzOS())
     return EHPersonality::ZOS_CPlusPlus;
@@ -197,6 +198,7 @@ static const EHPersonality &getCXXPersonality(const TargetInfo &Target,
 /// Determines the personality function to use when both C++
 /// and Objective-C exceptions are being caught.
 static const EHPersonality &getObjCXXPersonality(const TargetInfo &Target,
+                                                 const CodeGenOptions &CGOpts,
                                                  const LangOptions &L) {
   if (Target.getTriple().isWindowsMSVCEnvironment())
     return EHPersonality::MSVC_CxxFrameHandler3;
@@ -205,15 +207,15 @@ static const EHPersonality &getObjCXXPersonality(const TargetInfo &Target,
   // In the fragile ABI, just use C++ exception handling and hope
   // they're not doing crazy exception mixing.
   case ObjCRuntime::FragileMacOSX:
-    return getCXXPersonality(Target, L);
+    return getCXXPersonality(Target, CGOpts);
 
   // The ObjC personality defers to the C++ personality for non-ObjC
   // handlers.  Unlike the C++ case, we use the same personality
   // function on targets using (backend-driven) SJLJ EH.
   case ObjCRuntime::MacOSX:
   case ObjCRuntime::iOS:
   case ObjCRuntime::WatchOS:
-    return getObjCPersonality(Target, L);
+    return getObjCPersonality(Target, CGOpts, L);
 
   case ObjCRuntime::GNUstep:
     return Target.getTriple().isOSCygMing() ? EHPersonality::GNU_CPlusPlus_SEH
@@ -223,7 +225,7 @@ static const EHPersonality &getObjCXXPersonality(const TargetInfo &Target,
   // mixed EH.  Use the ObjC personality just to avoid returning null.
   case ObjCRuntime::GCC:
   case ObjCRuntime::ObjFW:
-    return getObjCPersonality(Target, L);
+    return getObjCPersonality(Target, CGOpts, L);
   }
   llvm_unreachable("bad runtime kind");
 }
@@ -237,6 +239,7 @@ static const EHPersonality &getSEHPersonalityMSVC(const llvm::Triple &T) {
 const EHPersonality &EHPersonality::get(CodeGenModule &CGM,
                                         const FunctionDecl *FD) {
   const llvm::Triple &T = CGM.getTarget().getTriple();
+  const CodeGenOptions &CGOpts = CGM.getCodeGenOpts();
   const LangOptions &L = CGM.getLangOpts();
   const TargetInfo &Target = CGM.getTarget();
 
@@ -245,10 +248,10 @@ const EHPersonality &EHPersonality::get(CodeGenModule &CGM,
     return getSEHPersonalityMSVC(T);
 
   if (L.ObjC)
-    return L.CPlusPlus ? getObjCXXPersonality(Target, L)
-                       : getObjCPersonality(Target, L);
-  return L.CPlusPlus ? getCXXPersonality(Target, L)
-                     : getCPersonality(Target, L);
+    return L.CPlusPlus ? getObjCXXPersonality(Target, CGOpts, L)
+                       : getObjCPersonality(Target, CGOpts, L);
+  return L.CPlusPlus ? getCXXPersonality(Target, CGOpts)
+                     : getCPersonality(Target, CGOpts);
 }
 
 const EHPersonality &EHPersonality::get(CodeGenFunction &CGF) {
@@ -344,7 +347,7 @@ void CodeGenModule::SimplifyPersonality() {
     return;
 
   const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
-  const EHPersonality &CXX = getCXXPersonality(getTarget(), LangOpts);
+  const EHPersonality &CXX = getCXXPersonality(getTarget(), CodeGenOpts);
   if (&ObjCXX == &CXX)
     return;
 
@@ -500,7 +503,7 @@ void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
     // In Wasm EH we currently treat 'throw()' in the same way as 'noexcept'. In
     // case of throw with types, we ignore it and print a warning for now.
     // TODO Correctly handle exception specification in Wasm EH
-    if (CGM.getLangOpts().hasWasmExceptions()) {
+    if (CGM.getCodeGenOpts().hasWasmExceptions()) {
       if (EST == EST_DynamicNone)
         EHStack.pushTerminate();
       else
@@ -515,8 +518,8 @@ void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
     // throw with types.
     // TODO Correctly handle exception specification in Emscripten EH
     if (getTarget().getCXXABI() == TargetCXXABI::WebAssembly &&
-        CGM.getLangOpts().getExceptionHandling() ==
-            LangOptions::ExceptionHandlingKind::None &&
+        CGM.getCodeGenOpts().getExceptionHandling() ==
+            CodeGenOptions::ExceptionHandlingKind::None &&
         EST == EST_Dynamic)
       CGM.getDiags().Report(D->getLocation(),
                             diag::warn_wasm_dynamic_exception_spec_ignored)
@@ -604,7 +607,7 @@ void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
     // In wasm we currently treat 'throw()' in the same way as 'noexcept'. In
     // case of throw with types, we ignore it and print a warning for now.
     // TODO Correctly handle exception specification in wasm
-    if (CGM.getLangOpts().hasWasmExceptions()) {
+    if (CGM.getCodeGenOpts().hasWasmExceptions()) {
       if (EST == EST_DynamicNone)
         EHStack.popTerminate();
       return;
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -593,11 +593,11 @@ static bool FixupInvocation(CompilerInvocation &Invocation,
   CodeGenOpts.CodeModel = TargetOpts.CodeModel;
   CodeGenOpts.LargeDataThreshold = TargetOpts.LargeDataThreshold;
 
-  if (LangOpts.getExceptionHandling() !=
-          LangOptions::ExceptionHandlingKind::None &&
+  if (CodeGenOpts.getExceptionHandling() !=
+          CodeGenOptions::ExceptionHandlingKind::None &&
       T.isWindowsMSVCEnvironment())
     Diags.Report(diag::err_fe_invalid_exception_model)
-        << static_cast<unsigned>(LangOpts.getExceptionHandling()) << T.str();
+        << static_cast<unsigned>(CodeGenOpts.getExceptionHandling()) << T.str();
 
   if (LangOpts.AppleKext && !LangOpts.CPlusPlus)
     Diags.Report(diag::warn_c_kext);
@@ -3713,23 +3713,6 @@ static StringRef GetInputKindName(InputKind IK) {
   llvm_unreachable("unknown input language");
 }
 
-static StringRef getExceptionHandlingName(unsigned EHK) {
-  switch (static_cast<LangOptions::ExceptionHandlingKind>(EHK)) {
-  case LangOptions::ExceptionHandlingKind::None:
-    return "none";
-  case LangOptions::ExceptionHandlingKind::DwarfCFI:
-    return "dwarf";
-  case LangOptions::ExceptionHandlingKind::SjLj:
-    return "sjlj";
-  case LangOptions::ExceptionHandlingKind::WinEH:
-    return "seh";
-  case LangOptions::ExceptionHandlingKind::Wasm:
-    return "wasm";
-  }
-
-  llvm_unreachable("covered switch");
-}
-
 void CompilerInvocationBase::GenerateLangArgs(const LangOptions &Opts,
                                               ArgumentConsumer Consumer,
                                               const llvm::Triple &T,
@@ -3745,10 +3728,6 @@ void CompilerInvocationBase::GenerateLangArgs(const LangOptions &Opts,
       GenerateArg(Consumer, OPT_pic_is_pie);
     for (StringRef Sanitizer : serializeSanitizerKinds(Opts.Sanitize))
       GenerateArg(Consumer, OPT_fsanitize_EQ, Sanitizer);
-    if (Opts.ExceptionHandling) {
-      GenerateArg(Consumer, OPT_exception_model,
-                  getExceptionHandlingName(Opts.ExceptionHandling));
-    }
 
     return;
   }
@@ -4057,24 +4036,6 @@ bool CompilerInvocation::ParseLangArgs(LangOptions &Opts, ArgList &Args,
     parseSanitizerKinds("-fsanitize=", Args.getAllArgValues(OPT_fsanitize_EQ),
                         Diags, Opts.Sanitize);
 
-    if (const Arg *A = Args.getLastArg(options::OPT_exception_model)) {
-      std::optional<LangOptions::ExceptionHandlingKind> EMValue =
-          llvm::StringSwitch<std::optional<LangOptions::ExceptionHandlingKind>>(
-              A->getValue())
-              .Case("dwarf", LangOptions::ExceptionHandlingKind::DwarfCFI)
-              .Case("sjlj", LangOptions::ExceptionHandlingKind::SjLj)
-              .Case("seh", LangOptions::ExceptionHandlingKind::WinEH)
-              .Case("wasm", LangOptions::ExceptionHandlingKind::Wasm)
-              .Case("none", LangOptions::ExceptionHandlingKind::None)
-              .Default(std::nullopt);
-      if (EMValue) {
-        Opts.ExceptionHandling = static_cast<unsigned>(*EMValue);
-      } else {
-        Diags.Report(diag::err_drv_invalid_value)
-            << A->getAsString(Args) << A->getValue();
-      }
-    }
-
     return Diags.getNumErrors() == NumErrorsBefore;
   }
 
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1032,14 +1032,14 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
   if (LangOpts.GNUCVersion && LangOpts.RTTI)
     Builder.defineMacro("__GXX_RTTI");
 
-  if (LangOpts.hasSjLjExceptions())
+  if (CGOpts.hasSjLjExceptions())
     Builder.defineMacro("__USING_SJLJ_EXCEPTIONS__");
-  else if (LangOpts.hasSEHExceptions())
+  else if (CGOpts.hasSEHExceptions())
     Builder.defineMacro("__SEH__");
-  else if (LangOpts.hasDWARFExceptions() &&
+  else if (CGOpts.hasDWARFExceptions() &&
            (TI.getTriple().isThumb() || TI.getTriple().isARM()))
     Builder.defineMacro("__ARM_DWARF_EH__");
-  else if (LangOpts.hasWasmExceptions() && TI.getTriple().isWasm())
+  else if (CGOpts.hasWasmExceptions() && TI.getTriple().isWasm())
     Builder.defineMacro("__WASM_EXCEPTIONS__");
 
   if (LangOpts.Deprecated)
