[MLIR] Fix genTypeInterfaceMethods() to work correctly with InferTypeOpInterface

[jurahul]

Summary

• Change InferTypeOpInterface::inferResultTypes to use fully qualified types matching the ones generated by genTypeInterfaceMethods, so the redundancy can be detected.
• Move genTypeInterfaceMethods() before genOpInterfaceMethods() so that the inferResultTypes method generated by genTypeInterfaceMethods() takes precedence over the declaration that might be generated by genOpInterfaceMethods()
• Modified an op in the test dialect to exercise this (the modified op would fail to generate valid C++ code due to duplicate inferResultTypes methods).

[jurahul]

The fix here is such that TableGen generated inferReturnTypes takes precedence over the one generated by the InferTypeOpInterface. Just tagging the Op with the trait is not sufficient since I assume we also want the generated inferReturnTypes. The other possible fix is to avoid generating the TableGen generated inferReturnTypes method when the Op is tagged with DeclareOpInterfaceMethods<InferTypeOpInterface> and delegate the definition of the method to the user. I've erred on the side of using the TableGen one.

[jpienaar]

Could we also remove the hard coding in genTypeInterfaceMethods ? (not for this one)

[jurahul]

In D92414#2426302, @jpienaar wrote:

Could we also remove the hard coding in genTypeInterfaceMethods ? (not for this one)

I did think of that, may be as a follow on change.

mlir/include/mlir/Interfaces/InferTypeOpInterface.td

StaticInterfaceMethod<
 
       The method takes an optional location which, if set, will be used to
       report errors on. The operands and attributes correspond to those with
       which an Operation would be created (e.g., as used in Operation::create)
       and the regions of the op.
       }],
       /*retTy=*/"LogicalResult",
       /*methodName=*/"inferReturnTypes",
-      /*args=*/(ins "MLIRContext*":$context,
-                    "Optional<Location>":$location,
-                    "ValueRange":$operands,
-                    "DictionaryAttr":$attributes,
-                    "RegionRange":$regions,
-                    "SmallVectorImpl<Type>&":$inferredReturnTypes)
+      /*args=*/(ins "::mlir::MLIRContext *":$context,
+                    "::llvm::Optional<::mlir::Location>":$location,
+                    "::mlir::ValueRange":$operands,
+                    "::mlir::DictionaryAttr":$attributes,
+                    "::mlir::RegionRange":$regions,
+                    "::llvm::SmallVectorImpl<::mlir::Type>&":$inferredReturnTypes)
     >,
     StaticInterfaceMethod<
       /*desc=*/"Returns whether two array of types are compatible result types"
                " for an op.",
       /*retTy=*/"bool",
       /*methodName=*/"isCompatibleReturnTypes",
-      /*args=*/(ins "ArrayRef<Type>":$lhs, "ArrayRef<Type>":$rhs),
+      /*args=*/(ins "::llvm::ArrayRef<::mlir::Type>":$lhs,
+                    "::llvm::ArrayRef<::mlir::Type>":$rhs),
       /*methodBody=*/[{
         return ConcreteOp::isCompatibleReturnTypes(lhs, rhs);
       }],
       /*defaultImplementation=*/[{
         /// Returns whether two arrays are equal as strongest check for
         /// compatibility by default.
         return lhs == rhs;
       }]

mlir/test/lib/Dialect/Test/TestOps.td

"MultiResultOpEnum", "Multi-result op kinds", [
     MultiResultOpKind4, MultiResultOpKind5, MultiResultOpKind6
   ]>;
 
 def ThreeResultOp : TEST_Op<"three_result"> {
   let arguments = (ins MultiResultOpEnum:$kind);
   let results = (outs I32:$result1, F32:$result2, F32:$result3);
 }
 
-def AnotherThreeResultOp : TEST_Op<"another_three_result"> {
+def AnotherThreeResultOp : TEST_Op<"another_three_result", [DeclareOpInterfaceMethods<InferTypeOpInterface>]> {
   let arguments = (ins MultiResultOpEnum:$kind);
   let results = (outs I32:$result1, F32:$result2, F32:$result3);
 }
 
 def TwoResultOp : TEST_Op<"two_result"> {
   let arguments = (ins MultiResultOpEnum:$kind);
   let results = (outs I32:$result1, F32:$result2);
 }

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

OpEmitter::OpEmitter(const Operator &op)
   genAttrGetters();
   genAttrSetters();
   genBuilder();
   genParser();
   genPrinter();
   genVerifier();
   genCanonicalizerDecls();
   genFolderDecls();
+  genTypeInterfaceMethods();
   genOpInterfaceMethods();
   generateOpFormat(op, opClass);
   genSideEffectInterfaceMethods();
-  genTypeInterfaceMethods();
 }
 
 void OpEmitter::emitDecl(const Operator &op, raw_ostream &os) {
   OpEmitter(op).emitDecl(os);
 }
 
 void OpEmitter::emitDef(const Operator &op, raw_ostream &os) {
   OpEmitter(op).emitDef(os);
void OpEmitter::genTypeInterfaceMethods() {
   paramList.emplace_back("::mlir::ValueRange", "operands");
   paramList.emplace_back("::mlir::DictionaryAttr", "attributes");
   paramList.emplace_back("::mlir::RegionRange", "regions");
   paramList.emplace_back("::llvm::SmallVectorImpl<::mlir::Type>&",
                          "inferredReturnTypes");
   auto *method =
       opClass.addMethodAndPrune("::mlir::LogicalResult", "inferReturnTypes",
                                 OpMethod::MP_Static, std::move(paramList));
-
   auto &body = method->body();
   body << "  inferredReturnTypes.resize(" << op.getNumResults() << ");\n";
 
   FmtContext fctx;
   fctx.withBuilder("odsBuilder");
   body << "  ::mlir::Builder odsBuilder(context);\n";
 
   auto emitType =