[M68k] Provide exception pointer and selector registers

Using d0 for exception pointer and d1 for selector, as suggested by GCC.

llvm/lib/Target/M68k/M68kISelLowering.cpp

@@ -191,6 +191,16 @@ M68kTargetLowering::shouldExpandAtomicRMWInIR(AtomicRMWInst *RMW) const {
              : TargetLoweringBase::AtomicExpansionKind::None;
 }
 
+Register
+M68kTargetLowering::getExceptionPointerRegister(const Constant *) const {
+  return M68k::D0;
+}
+
+Register
+M68kTargetLowering::getExceptionSelectorRegister(const Constant *) const {
+  return M68k::D1;
+}
+
 EVT M68kTargetLowering::getSetCCResultType(const DataLayout &DL,
                                            LLVMContext &Context, EVT VT) const {
   // M68k SETcc producess either 0x00 or 0xFF

llvm/lib/Target/M68k/M68kISelLowering.h

@@ -177,6 +177,16 @@ class M68kTargetLowering : public TargetLowering {
   AtomicExpansionKind
   shouldExpandAtomicRMWInIR(AtomicRMWInst *RMW) const override;
 
+  /// If a physical register, this returns the register that receives the
+  /// exception address on entry to an EH pad.
+  Register
+  getExceptionPointerRegister(const Constant *PersonalityFn) const override;
+
+  /// If a physical register, this returns the register that receives the
+  /// exception typeid on entry to a landing pad.
+  Register
+  getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
+
 private:
   unsigned GetAlignedArgumentStackSize(unsigned StackSize,
                                        SelectionDAG &DAG) const;

llvm/test/CodeGen/M68k/gcc_except_table.ll

@@ -0,0 +1,48 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=m68k < %s | FileCheck %s
+
+; (Copied from test/CodeGen/X86/gcc_except_table.ll)
+; Testing whether exception pointer register (d0) and exception selector
+; register (d1) are correctly used by landing and EH pad, respectively.
+@_ZTIi = external constant ptr
+
+define i32 @foo() uwtable ssp personality ptr @__gxx_personality_v0 {
+; CHECK-LABEL: foo:
+; CHECK:       .Lfunc_begin0:
+; CHECK-NEXT:    .cfi_startproc
+; CHECK-NEXT:    .cfi_personality 0, __gxx_personality_v0
+; CHECK-NEXT:    .cfi_lsda 0, .Lexception0
+; CHECK-NEXT:  ; %bb.0: ; %entry
+; CHECK-NEXT:    suba.l #4, %sp
+; CHECK-NEXT:    .cfi_def_cfa_offset -8
+; CHECK-NEXT:  .Ltmp0:
+; CHECK-NEXT:    jsr _Z1fv@PLT
+; CHECK-NEXT:  .Ltmp1:
+; CHECK-NEXT:  ; %bb.1: ; %try.cont
+; CHECK-NEXT:    move.l #0, %d0
+; CHECK-NEXT:    adda.l #4, %sp
+; CHECK-NEXT:    rts
+; CHECK-NEXT:  .LBB0_2: ; %lpad
+; CHECK-NEXT:  .Ltmp2:
+; CHECK-NEXT:    move.l %d0, (%sp)
+; CHECK-NEXT:    jsr _Unwind_Resume@PLT
+entry:
+  invoke void @_Z1fv() optsize
+          to label %try.cont unwind label %lpad
+
+lpad:
+  %0 = landingpad { ptr, i32 }
+          cleanup
+          catch ptr @_ZTIi
+  br label %eh.resume
+
+try.cont:
+  ret i32 0
+
+eh.resume:
+  resume { ptr, i32 } %0
+}
+
+declare void @_Z1fv() optsize
+
+declare i32 @__gxx_personality_v0(...)