[tblgen] Add getOperatorAsDef() to Record

Summary:
While working with DagInit's, it's often the case that you expect the
operator to be a reference to a def. This patch adds a wrapper for this
common case to reduce the amount of boilerplate callers need to duplicate
repeatedly.

getOperatorAsDef() returns the record if the DagInit has an operator that is
a DefInit. Otherwise, it prints a fatal error.

There's only a few pre-existing examples in LLVM at the moment and I've
left a few instances of the code this simplifies as they had more specific
error messages than the generic one this produces. I'm going to be using
this a fair bit in my subsequent patches.

Reviewers: bogner, volkan, nhaehnle

Reviewed By: nhaehnle

Subscribers: nhaehnle, hiraditya, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, lenary, s.egerton, pzheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68424

llvm-svn: 374101

1 files changed, 7 insertions, 0 deletions

diff --git a/llvm/lib/TableGen/Record.cpp b/llvm/lib/TableGen/Record.cpp
index e4ab39df087..41c44280d83 100644
--- a/llvm/lib/TableGen/Record.cpp
+++ b/llvm/lib/TableGen/Record.cpp
@@ -1930,6 +1930,13 @@ void DagInit::Profile(FoldingSetNodeID &ID) const {
   ProfileDagInit(ID, Val, ValName, makeArrayRef(getTrailingObjects<Init *>(), NumArgs), makeArrayRef(getTrailingObjects<StringInit *>(), NumArgNames));
 }
 
+Record *DagInit::getOperatorAsDef(ArrayRef<SMLoc> Loc) const {
+  if (DefInit *DefI = dyn_cast<DefInit>(Val))
+    return DefI->getDef();
+  PrintFatalError(Loc, "Expected record as operator");
+  return nullptr;
+}
+
 Init *DagInit::resolveReferences(Resolver &R) const {
   SmallVector<Init*, 8> NewArgs;
   NewArgs.reserve(arg_size());