[SEH] Implement GetExceptionCode in __except blocks
This introduces an intrinsic called llvm.eh.exceptioncode. It is lowered
by copying the EAX value live into whatever basic block it is called
from. Obviously, this only works if you insert it late during codegen,
because otherwise mid-level passes might reschedule it.
llvm-svn: 235768
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 01419cf..fd59d57 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4817,6 +4817,18 @@
case Intrinsic::eh_begincatch:
case Intrinsic::eh_endcatch:
llvm_unreachable("begin/end catch intrinsics not lowered in codegen");
+ case Intrinsic::eh_exceptioncode: {
+ unsigned Reg = TLI.getExceptionPointerRegister();
+ assert(Reg && "cannot get exception code on this platform");
+ MVT PtrVT = TLI.getPointerTy();
+ const TargetRegisterClass *PtrRC = TLI.getRegClassFor(PtrVT);
+ unsigned VReg = FuncInfo.MBB->addLiveIn(Reg, PtrRC);
+ SDValue N =
+ DAG.getCopyFromReg(DAG.getEntryNode(), getCurSDLoc(), VReg, PtrVT);
+ N = DAG.getZExtOrTrunc(N, getCurSDLoc(), MVT::i32);
+ setValue(&I, N);
+ return nullptr;
+ }
}
}