[LoongArch] Specify registers used in DWARF exception handling

[wangleiat]

Summary

Defines LoongArch registers for getExceptionPointerRegister() and
getExceptionSelectorRegister().

[xen0n]

Straight-forward enough. Thanks!

llvm/lib/Target/LoongArch/LoongArchISelLowering.h

public:
 
   bool getTgtMemIntrinsic(IntrinsicInfo &Info, const CallInst &I,
                           MachineFunction &MF,
                           unsigned Intrinsic) const override;
 
   bool isFMAFasterThanFMulAndFAdd(const MachineFunction &MF,
                                   EVT VT) const override;
 
+  Register
+  getExceptionPointerRegister(const Constant *PersonalityFn) const override;
+
+  Register
+  getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
+
 private:
   /// Target-specific function used to lower LoongArch calling conventions.
   typedef bool LoongArchCCAssignFn(const DataLayout &DL, LoongArchABI::ABI ABI,
                                    unsigned ValNo, MVT ValVT,
                                    CCValAssign::LocInfo LocInfo,
                                    ISD::ArgFlagsTy ArgFlags, CCState &State,
                                    bool IsFixed, bool IsReg, Type *OrigTy);
 

llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp

case MVT::f64:
     return true;
   default:
     break;
   }
 
   return false;
 }
 
+Register LoongArchTargetLowering::getExceptionPointerRegister(
+    const Constant *PersonalityFn) const {
+  return LoongArch::R4;
+}
+
+Register LoongArchTargetLowering::getExceptionSelectorRegister(
+    const Constant *PersonalityFn) const {
+  return LoongArch::R5;
+}
+
 //===----------------------------------------------------------------------===//
 //                           LoongArch Inline Assembly Support
 //===----------------------------------------------------------------------===//
 
 LoongArchTargetLowering::ConstraintType
 LoongArchTargetLowering::getConstraintType(StringRef Constraint) const {
   // LoongArch specific constraints in GCC: config/loongarch/constraints.md
   //

llvm/test/CodeGen/LoongArch/exception-pointer-register.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc --mtriple=loongarch32 --verify-machineinstrs < %s \
+; RUN:    | FileCheck %s --check-prefix=LA32
+; RUN: llc --mtriple=loongarch64 --verify-machineinstrs < %s \
+; RUN:    | FileCheck %s --check-prefix=LA64
+
+declare void @foo(ptr %p);
+declare void @bar(ptr %p);
+declare dso_local i32 @__gxx_personality_v0(...)
+
+;; Before getExceptionPointerRegister() and getExceptionSelectorRegister()
+;; lowering hooks were defined this would trigger an assertion during live
+;; variable analysis.
+
+define void @caller(ptr %p) personality ptr @__gxx_personality_v0 {
+; LA32-LABEL: caller:
+; LA32:       # %bb.0: # %entry
+; LA32-NEXT:    addi.w $sp, $sp, -16
+; LA32-NEXT:    .cfi_def_cfa_offset 16
+; LA32-NEXT:    st.w $ra, $sp, 12 # 4-byte Folded Spill
+; LA32-NEXT:    st.w $fp, $sp, 8 # 4-byte Folded Spill
+; LA32-NEXT:    st.w $s0, $sp, 4 # 4-byte Folded Spill
+; LA32-NEXT:    .cfi_offset 1, -4
+; LA32-NEXT:    .cfi_offset 22, -8
+; LA32-NEXT:    .cfi_offset 23, -12
+; LA32-NEXT:    move $fp, $a0
+; LA32-NEXT:    beqz $a0, .LBB0_1
+; LA32-NEXT:  # %bb.2: # %bb2
+; LA32-NEXT:  .Ltmp0:
+; LA32-NEXT:    move $a0, $fp
+; LA32-NEXT:    bl %plt(bar)
+; LA32-NEXT:  .Ltmp1:
+; LA32-NEXT:    b .LBB0_3
+; LA32-NEXT:  .LBB0_1: # %bb1
+; LA32-NEXT:  .Ltmp2:
+; LA32-NEXT:    move $a0, $fp
+; LA32-NEXT:    bl %plt(foo)
+; LA32-NEXT:  .Ltmp3:
+; LA32-NEXT:  .LBB0_3: # %end2
+; LA32-NEXT:    ld.w $s0, $sp, 4 # 4-byte Folded Reload
+; LA32-NEXT:    ld.w $fp, $sp, 8 # 4-byte Folded Reload
+; LA32-NEXT:    ld.w $ra, $sp, 12 # 4-byte Folded Reload
+; LA32-NEXT:    addi.w $sp, $sp, 16
+; LA32-NEXT:    ret
+; LA32-NEXT:  .LBB0_4: # %lpad
+; LA32-NEXT:  .Ltmp4:
+; LA32-NEXT:    move $s0, $a0
+; LA32-NEXT:    move $a0, $fp
+; LA32-NEXT:    bl callee
+; LA32-NEXT:    move $a0, $s0
+; LA32-NEXT:    bl %plt(_Unwind_Resume)
+;
+; LA64-LABEL: caller:
+; LA64:       # %bb.0: # %entry
+; LA64-NEXT:    addi.d $sp, $sp, -32
+; LA64-NEXT:    .cfi_def_cfa_offset 32
+; LA64-NEXT:    st.d $ra, $sp, 24 # 8-byte Folded Spill
+; LA64-NEXT:    st.d $fp, $sp, 16 # 8-byte Folded Spill
+; LA64-NEXT:    st.d $s0, $sp, 8 # 8-byte Folded Spill
+; LA64-NEXT:    .cfi_offset 1, -8
+; LA64-NEXT:    .cfi_offset 22, -16
+; LA64-NEXT:    .cfi_offset 23, -24
+; LA64-NEXT:    move $fp, $a0
+; LA64-NEXT:    beqz $a0, .LBB0_1
+; LA64-NEXT:  # %bb.2: # %bb2
+; LA64-NEXT:  .Ltmp0:
+; LA64-NEXT:    move $a0, $fp
+; LA64-NEXT:    bl %plt(bar)
+; LA64-NEXT:  .Ltmp1:
+; LA64-NEXT:    b .LBB0_3
+; LA64-NEXT:  .LBB0_1: # %bb1
+; LA64-NEXT:  .Ltmp2:
+; LA64-NEXT:    move $a0, $fp
+; LA64-NEXT:    bl %plt(foo)
+; LA64-NEXT:  .Ltmp3:
+; LA64-NEXT:  .LBB0_3: # %end2
+; LA64-NEXT:    ld.d $s0, $sp, 8 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $fp, $sp, 16 # 8-byte Folded Reload
+; LA64-NEXT:    ld.d $ra, $sp, 24 # 8-byte Folded Reload
+; LA64-NEXT:    addi.d $sp, $sp, 32
+; LA64-NEXT:    ret
+; LA64-NEXT:  .LBB0_4: # %lpad
+; LA64-NEXT:  .Ltmp4:
+; LA64-NEXT:    move $s0, $a0
+; LA64-NEXT:    move $a0, $fp
+; LA64-NEXT:    bl callee
+; LA64-NEXT:    move $a0, $s0
+; LA64-NEXT:    bl %plt(_Unwind_Resume)
+entry:
+  %0 = icmp eq ptr %p, null
+  br i1 %0, label %bb1, label %bb2
+
+bb1:
+  invoke void @foo(ptr %p) to label %end1 unwind label %lpad
+
+bb2:
+  invoke void @bar(ptr %p) to label %end2 unwind label %lpad
+
+lpad:
+  %1 = landingpad { ptr, i32 } cleanup
+  call void @callee(ptr %p)
+  resume { ptr, i32 } %1
+
+end1:
+  ret void
+
+end2:
+  ret void
+}
+
+define internal void @callee(ptr %p) {
+; LA32-LABEL: callee:
+; LA32:       # %bb.0:
+; LA32-NEXT:    ret
+;
+; LA64-LABEL: callee:
+; LA64:       # %bb.0:
+; LA64-NEXT:    ret
+  ret void
+}