[MLIR] Combine the 2 overloads of FuncOp::build() into one.

[jurahul]

Summary

• This will eliminate the need to pass an empty ArrayRef<NamedAttribute>{} when no named attributes are required on the function.

mlir/include/mlir/IR/Function.h

static FuncOp create(Location location, StringRef name, FunctionType type,
                        ArrayRef<NamedAttribute> attrs = {});
   static FuncOp create(Location location, StringRef name, FunctionType type,
                        iterator_range<dialect_attr_iterator> attrs);
   static FuncOp create(Location location, StringRef name, FunctionType type,
                        ArrayRef<NamedAttribute> attrs,
                        ArrayRef<MutableDictionaryAttr> argAttrs);
 
   static void build(OpBuilder &builder, OperationState &result, StringRef name,
-                    FunctionType type, ArrayRef<NamedAttribute> attrs);
-  static void build(OpBuilder &builder, OperationState &result, StringRef name,
-                    FunctionType type, ArrayRef<NamedAttribute> attrs,
-                    ArrayRef<MutableDictionaryAttr> argAttrs);
+                    FunctionType type, ArrayRef<NamedAttribute> attrs = {},
+                    ArrayRef<MutableDictionaryAttr> argAttrs = {});
 
   /// Operation hooks.
   static ParseResult parse(OpAsmParser &parser, OperationState &result);
   void print(OpAsmPrinter &p);
   LogicalResult verify();
 
   /// Erase a single argument at `argIndex`.
   void eraseArgument(unsigned argIndex) { eraseArguments({argIndex}); }

mlir/lib/Conversion/GPUToVulkan/ConvertGPULaunchFuncToVulkanLaunchFunc.cpp

for (auto type :
        llvm::drop_begin(vulkanLaunchTypes, kVulkanLaunchNumConfigOperands)) {
     if (!isSupportedType(type))
       return launchOp.emitError() << type << " is unsupported to run on Vulkan";
   }
 
   // Declare vulkan launch function.
   builder.create<FuncOp>(
       loc, kVulkanLaunch,
-      FunctionType::get(vulkanLaunchTypes, ArrayRef<Type>{}, loc->getContext()),
-      ArrayRef<NamedAttribute>{});
+      FunctionType::get(vulkanLaunchTypes, {}, loc->getContext()));
 
   return success();
 }
 
 LogicalResult ConvertGpuLaunchFuncToVulkanLaunchFunc::createBinaryShader(
     ModuleOp module, std::vector<char> &binaryShader) {
   bool done = false;
   SmallVector<uint32_t, 0> binary;

mlir/lib/Conversion/LinalgToStandard/LinalgToStandard.cpp

assert(op->getNumResults() == 0 &&
          "have void return types");
   auto libFnType = FunctionType::get(inputTypes, {}, rewriter.getContext());
 
   OpBuilder::InsertionGuard guard(rewriter);
   // Insert before module terminator.
   rewriter.setInsertionPoint(module.getBody(),
                              std::prev(module.getBody()->end()));
   FuncOp funcOp =
-      rewriter.create<FuncOp>(op->getLoc(), fnNameAttr.getValue(), libFnType,
-                              ArrayRef<NamedAttribute>{});
+      rewriter.create<FuncOp>(op->getLoc(), fnNameAttr.getValue(), libFnType);
   // Insert a function attribute that will trigger the emission of the
   // corresponding `_mlir_ciface_xxx` interface so that external libraries see
   // a normalized ABI. This interface is added during std to llvm conversion.
   funcOp.setAttr("llvm.emit_c_interface", UnitAttr::get(op->getContext()));
   return fnNameAttr;
 }
 
 namespace {

mlir/lib/IR/Function.cpp

FuncOp FuncOp::create(Location location, StringRef name, FunctionType type,
                       ArrayRef<NamedAttribute> attrs,
                       ArrayRef<MutableDictionaryAttr> argAttrs) {
   FuncOp func = create(location, name, type, attrs);
   func.setAllArgAttrs(argAttrs);
   return func;
 }
 
 void FuncOp::build(OpBuilder &builder, OperationState &result, StringRef name,
-                   FunctionType type, ArrayRef<NamedAttribute> attrs) {
+                   FunctionType type, ArrayRef<NamedAttribute> attrs,
+                   ArrayRef<MutableDictionaryAttr> argAttrs) {
   result.addAttribute(SymbolTable::getSymbolAttrName(),
                       builder.getStringAttr(name));
   result.addAttribute(getTypeAttrName(), TypeAttr::get(type));
   result.attributes.append(attrs.begin(), attrs.end());
   result.addRegion();
-}
 
-void FuncOp::build(OpBuilder &builder, OperationState &result, StringRef name,
-                   FunctionType type, ArrayRef<NamedAttribute> attrs,
-                   ArrayRef<MutableDictionaryAttr> argAttrs) {
-  build(builder, result, name, type, attrs);
+  if (argAttrs.empty())
+    return;
   assert(type.getNumInputs() == argAttrs.size());
   SmallString<8> argAttrName;
   for (unsigned i = 0, e = type.getNumInputs(); i != e; ++i)
     if (auto argDict = argAttrs[i].getDictionary(builder.getContext()))
       result.addAttribute(getArgAttrName(i, argAttrName), argDict);
 }
 
 /// Parsing/Printing methods.