ARM: Remove subtarget field tracking SjLj

llvm/include/llvm/Target/TargetMachine.h

@@ -243,6 +243,15 @@ class LLVM_ABI TargetMachine {
   const MCInstrInfo *getMCInstrInfo() const { return MII.get(); }
   const MCSubtargetInfo *getMCSubtargetInfo() const { return STI.get(); }
 
+  /// Return the ExceptionHandling to use, considering TargetOptions and the
+  /// Triple's default.
+  ExceptionHandling getExceptionModel() const {
+    // FIXME: This interface fails to distinguish default from not supported.
+    return Options.ExceptionModel == ExceptionHandling::None
+               ? TargetTriple.getDefaultExceptionHandling()
+               : Options.ExceptionModel;
+  }
+
   bool requiresStructuredCFG() const { return RequireStructuredCFG; }
   void setRequiresStructuredCFG(bool Value) { RequireStructuredCFG = Value; }
 

llvm/lib/Target/ARM/ARMISelLowering.cpp

@@ -21959,14 +21959,16 @@ Register ARMTargetLowering::getExceptionPointerRegister(
     const Constant *PersonalityFn) const {
   // Platforms which do not use SjLj EH may return values in these registers
   // via the personality function.
-  return Subtarget->useSjLjEH() ? Register() : ARM::R0;
+  ExceptionHandling EM = getTargetMachine().getExceptionModel();
+  return EM == ExceptionHandling::SjLj ? Register() : ARM::R0;
 }
 
 Register ARMTargetLowering::getExceptionSelectorRegister(
     const Constant *PersonalityFn) const {
   // Platforms which do not use SjLj EH may return values in these registers
   // via the personality function.
-  return Subtarget->useSjLjEH() ? Register() : ARM::R1;
+  ExceptionHandling EM = getTargetMachine().getExceptionModel();
+  return EM == ExceptionHandling::SjLj ? Register() : ARM::R1;
 }
 
 void ARMTargetLowering::initializeSplitCSR(MachineBasicBlock *Entry) const {

llvm/lib/Target/ARM/ARMSubtarget.cpp

@@ -72,7 +72,6 @@ ForceFastISel("arm-force-fast-isel",
 /// so that we can use initializer lists for subtarget initialization.
 ARMSubtarget &ARMSubtarget::initializeSubtargetDependencies(StringRef CPU,
                                                             StringRef FS) {
-  initializeEnvironment();
   initSubtargetFeatures(CPU, FS);
   return *this;
 }
@@ -137,19 +136,6 @@ bool ARMSubtarget::isXRaySupported() const {
   return hasV6Ops() && hasARMOps() && !isTargetWindows();
 }
 
-void ARMSubtarget::initializeEnvironment() {
-  // MCAsmInfo isn't always present (e.g. in opt) so we can't initialize this
-  // directly from it, but we can try to make sure they're consistent when both
-  // available.
-  UseSjLjEH = (isTargetDarwin() && !isTargetWatchABI() &&
-               Options.ExceptionModel == ExceptionHandling::None) ||
-              Options.ExceptionModel == ExceptionHandling::SjLj;
-  assert((!TM.getMCAsmInfo() ||
-          (TM.getMCAsmInfo()->getExceptionHandlingType() ==
-           ExceptionHandling::SjLj) == UseSjLjEH) &&
-         "inconsistent sjlj choice between CodeGen and MC");
-}
-
 void ARMSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
   if (CPUString.empty()) {
     CPUString = "generic";

llvm/lib/Target/ARM/ARMSubtarget.h

@@ -151,9 +151,6 @@ class ARMSubtarget : public ARMGenSubtargetInfo {
   ///  blocks.
   bool RestrictIT = false;
 
-  /// UseSjLjEH - If true, the target uses SjLj exception handling (e.g. iOS).
-  bool UseSjLjEH = false;
-
   /// stackAlignment - The minimum alignment known to hold of the stack frame on
   /// entry to the function and which must be maintained by every function.
   Align stackAlignment = Align(4);
@@ -270,7 +267,6 @@ class ARMSubtarget : public ARMGenSubtargetInfo {
   std::unique_ptr<LegalizerInfo> Legalizer;
   std::unique_ptr<RegisterBankInfo> RegBankInfo;
 
-  void initializeEnvironment();
   void initSubtargetFeatures(StringRef CPU, StringRef FS);
   ARMFrameLowering *initializeFrameLowering(StringRef CPU, StringRef FS);
 
@@ -321,7 +317,6 @@ class ARMSubtarget : public ARMGenSubtargetInfo {
   }
   bool useFPVFMx16() const { return useFPVFMx() && hasFullFP16(); }
   bool useFPVFMx64() const { return useFPVFMx() && hasFP64(); }
-  bool useSjLjEH() const { return UseSjLjEH; }
   bool hasBaseDSP() const {
     if (isThumb())
       return hasThumb2() && hasDSP();