[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

2 files changed, 3 insertions, 13 deletions

diff --git a/llvm/utils/TableGen/AsmWriterEmitter.cpp b/llvm/utils/TableGen/AsmWriterEmitter.cpp
index 05d81f13350..b5c7f35be0e 100644
--- a/llvm/utils/TableGen/AsmWriterEmitter.cpp
+++ b/llvm/utils/TableGen/AsmWriterEmitter.cpp
@@ -784,8 +784,7 @@ void AsmWriterEmitter::EmitPrintAliasInstruction(raw_ostream &O) {
       continue; // Aliases with priority 0 are never emitted.
 
     const DagInit *DI = R->getValueAsDag("ResultInst");
-    const DefInit *Op = cast<DefInit>(DI->getOperator());
-    AliasMap[getQualifiedName(Op->getDef())].insert(
+    AliasMap[getQualifiedName(DI->getOperatorAsDef(R->getLoc()))].insert(
         std::make_pair(CodeGenInstAlias(R, Target), Priority));
   }
 
diff --git a/llvm/utils/TableGen/RISCVCompressInstEmitter.cpp b/llvm/utils/TableGen/RISCVCompressInstEmitter.cpp
index e62f528ebc2..2f1d3898f18 100644
--- a/llvm/utils/TableGen/RISCVCompressInstEmitter.cpp
+++ b/llvm/utils/TableGen/RISCVCompressInstEmitter.cpp
@@ -411,12 +411,8 @@ void RISCVCompressInstEmitter::evaluateCompressPat(Record *Rec) {
   assert(SourceDag && "Missing 'Input' in compress pattern!");
   LLVM_DEBUG(dbgs() << "Input: " << *SourceDag << "\n");
 
-  DefInit *OpDef = dyn_cast<DefInit>(SourceDag->getOperator());
-  if (!OpDef)
-    PrintFatalError(Rec->getLoc(),
-                    Rec->getName() + " has unexpected operator type!");
   // Checking we are transforming from compressed to uncompressed instructions.
-  Record *Operator = OpDef->getDef();
+  Record *Operator = SourceDag->getOperatorAsDef(Rec->getLoc());
   if (!Operator->isSubClassOf("RVInst"))
     PrintFatalError(Rec->getLoc(), "Input instruction '" + Operator->getName() +
                                        "' is not a 32 bit wide instruction!");
@@ -428,12 +424,7 @@ void RISCVCompressInstEmitter::evaluateCompressPat(Record *Rec) {
   assert(DestDag && "Missing 'Output' in compress pattern!");
   LLVM_DEBUG(dbgs() << "Output: " << *DestDag << "\n");
 
-  DefInit *DestOpDef = dyn_cast<DefInit>(DestDag->getOperator());
-  if (!DestOpDef)
-    PrintFatalError(Rec->getLoc(),
-                    Rec->getName() + " has unexpected operator type!");
-
-  Record *DestOperator = DestOpDef->getDef();
+  Record *DestOperator = DestDag->getOperatorAsDef(Rec->getLoc());
   if (!DestOperator->isSubClassOf("RVInst16"))
     PrintFatalError(Rec->getLoc(), "Output instruction  '" +
                                        DestOperator->getName() +