Emit the boilerplate for Attribute printer/parser dialect dispatching from ODS

[mehdi_amini]

Summary

Add a new useDefaultAttributePrinterParser boolean settings on the dialect
(default to false for now) that emits the boilerplate to dispatch attribute
parsing/printing to the auto-generated method.
We will likely turn this on by default in the future.

Depends On D113327

[mehdi_amini]

Tweak the location used on keyword mismatch

[mehdi_amini]

Fully qualify namespace

[rriddle]

Much nicer!!

mlir/include/mlir/IR/OpBase.td

class Dialect {
   bit hasRegionArgAttrVerify = 0;
 
   // If this dialect overrides the hook for verifying region result attributes.
   bit hasRegionResultAttrVerify = 0;
 
   // If this dialect overrides the hook for op interface fallback.
   bit hasOperationInterfaceFallback = 0;
 
+  // If this dialect should use default generated attribute parser boilerplate:
+  // it'll dispatch the parsing to every individual attributes directly.
+  bit useDefaultAttributePrinterParser = 0;
+
   // If this dialect overrides the hook for canonicalization patterns.
   bit hasCanonicalizer = 0;
 
   // Whether to emit raw/with no prefix or format changes, or emit with
   // accessor with prefix only and UpperCamel suffix or to emit accessors with
   // both.
   //
   // If emitting with prefix is specified then the attribute/operand's

mlir/include/mlir/TableGen/Dialect.h

public:
   bool hasRegionArgAttrVerify() const;
 
   /// Returns true if this dialect has a region result attribute verifier.
   bool hasRegionResultAttrVerify() const;
 
   /// Returns true if this dialect has fallback interfaces for its operations.
   bool hasOperationInterfaceFallback() const;
 
+  /// Returns true if this dialect should generate the default dispatch for
+  /// attribute printing/parsing.
+  bool useDefaultAttributePrinterParser() const;
+
   // Returns whether two dialects are equal by checking the equality of the
   // underlying record.
   bool operator==(const Dialect &other) const;
 
   bool operator!=(const Dialect &other) const { return !(*this == other); }
 
   // Compares two dialects by comparing the names of the dialects.
   bool operator<(const Dialect &other) const;

mlir/lib/TableGen/Dialect.cpp

 bool Dialect::hasRegionResultAttrVerify() const {
   return def->getValueAsBit("hasRegionResultAttrVerify");
 }
 
 bool Dialect::hasOperationInterfaceFallback() const {
   return def->getValueAsBit("hasOperationInterfaceFallback");
 }
 
+bool Dialect::useDefaultAttributePrinterParser() const {
+  return def->getValueAsBit("useDefaultAttributePrinterParser");
+}
+
 Dialect::EmitPrefix Dialect::getEmitAccessorPrefix() const {
   int prefix = def->getValueAsInt("emitAccessorPrefix");
   if (prefix < 0 || prefix > static_cast<int>(EmitPrefix::Both))
     PrintFatalError(def->getLoc(), "Invalid accessor prefix value");
   return static_cast<EmitPrefix>(prefix);
 }
 
 bool Dialect::operator==(const Dialect &other) const {
   return def == other.def;
 }
 
 bool Dialect::operator<(const Dialect &other) const {
   return getName() < other.getName();
 }

mlir/test/lib/Dialect/Test/TestAttributes.cpp

 //===----------------------------------------------------------------------===//
 
 void TestDialect::registerAttributes() {
   addAttributes<
 #define GET_ATTRDEF_LIST
 #include "TestAttrDefs.cpp.inc"
       >();
 }
-
-Attribute TestDialect::parseAttribute(DialectAsmParser &parser,
-                                      Type type) const {
-  StringRef attrTag;
-  if (failed(parser.parseKeyword(&attrTag)))
-    return Attribute();
-  {
-    Attribute attr;
-    auto parseResult = generatedAttributeParser(parser, attrTag, type, attr);
-    if (parseResult.hasValue())
-      return attr;
-  }
-  parser.emitError(parser.getNameLoc(), "unknown test attribute");
-  return Attribute();
-}
-
-void TestDialect::printAttribute(Attribute attr,
-                                 DialectAsmPrinter &printer) const {
-  if (succeeded(generatedAttributePrinter(attr, printer)))
-    return;
-}

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

def Test_Dialect : Dialect {
   let emitAccessorPrefix = kEmitAccessorPrefix_Prefixed;
   let hasCanonicalizer = 1;
   let hasConstantMaterializer = 1;
   let hasOperationAttrVerify = 1;
   let hasRegionArgAttrVerify = 1;
   let hasRegionResultAttrVerify = 1;
   let hasOperationInterfaceFallback = 1;
   let hasNonDefaultDestructor = 1;
+  let useDefaultAttributePrinterParser = 1;
   let dependentDialects = ["::mlir::DLTIDialect"];
 
   let extraClassDeclaration = [{
     void registerAttributes();
     void registerTypes();
 
     // Provides a custom printing/parsing for some operations.
     ::llvm::Optional<ParseOpHook>

mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp

 /// {1}: Additional parser parameters.
 static const char *const defParserDispatchStartStr = R"(
 static ::mlir::OptionalParseResult generated{0}Parser(
                                       ::mlir::DialectAsmParser &parser,
                                       ::llvm::StringRef mnemonic{1},
                                       ::mlir::{0} &value) {{
 )";
 
+/// The code block for default attribute parser/printer dispatch boilerplate.
+/// {0}: the dialect fully qualified class name.
+static const char *const dialectDefaultAttrPrinterParserDispatch = R"(
+/// Parse an attribute registered to this dialect.
+::mlir::Attribute {0}::parseAttribute(::mlir::DialectAsmParser &parser,
+                                      ::mlir::Type type) const {{
+  ::llvm::SMLoc typeLoc = parser.getCurrentLocation();
+  ::llvm::StringRef attrTag;
+  if (failed(parser.parseKeyword(&attrTag)))
+    return {{};
+  {{
+    ::mlir::Attribute attr;
+    auto parseResult = generatedAttributeParser(parser, attrTag, type, attr);
+    if (parseResult.hasValue())
+      return attr;
+  }
+  parser.emitError(typeLoc) << "unknown  attribute `"
+      << attrTag << "` in dialect `" << getNamespace() << "`";
+  return {{};
+}
+/// Print an attribute registered to this dialect.
+void {0}::printAttribute(::mlir::Attribute attr,
+                         ::mlir::DialectAsmPrinter &printer) const {{
+  if (succeeded(generatedAttributePrinter(attr, printer)))
+    return;
+}
+)";
+
 /// The code block used to start the auto-generated printer function.
 ///
 /// {0}: The name of the base value type, e.g. Attribute or Type.
 static const char *const defPrinterDispatchStartStr = R"(
 static ::mlir::LogicalResult generated{0}Printer(
                          ::mlir::{0} def, ::mlir::DialectAsmPrinter &printer) {{
   return ::llvm::TypeSwitch<::mlir::{0}, ::mlir::LogicalResult>(def)
 )";
bool DefGenerator::emitDefs(StringRef selectedDialect) {
   for (const AttrOrTypeDef &def : defs) {
     emitDefDef(def);
     // Emit the TypeID explicit specializations to have a single symbol def.
     if (!def.getDialect().getCppNamespace().empty())
       os << "DEFINE_EXPLICIT_TYPE_ID(" << def.getDialect().getCppNamespace()
          << "::" << def.getCppClassName() << ")\n";
   }
 
+  // Emit the default parser/printer for Attributes if the dialect asked for it.
+  if (valueType == "Attribute" &&
+      defs.front().getDialect().useDefaultAttributePrinterParser())
+    os << llvm::formatv(dialectDefaultAttrPrinterParserDispatch,
+                        defs.front().getDialect().getCppClassName());
+
   return false;
 }
 
 //===----------------------------------------------------------------------===//
 // GEN: Registration hooks
 //===----------------------------------------------------------------------===//
 
 //===----------------------------------------------------------------------===//

mlir/tools/mlir-tblgen/DialectGen.cpp

// Emit all nested namespaces.
 
     // Emit the start of the decl.
     std::string cppName = dialect.getCppClassName();
     os << llvm::formatv(dialectDeclBeginStr, cppName, dialect.getName(),
                         dependentDialectRegistrations);
 
     // Check for any attributes/types registered to this dialect.  If there are,
     // add the hooks for parsing/printing.
-    if (!dialectAttrs.empty())
+    if (!dialectAttrs.empty() || dialect.useDefaultAttributePrinterParser())
       os << attrParserDecl;
     if (!dialectTypes.empty())
       os << typeParserDecl;
 
     // Add the decls for the various features of the dialect.
     if (dialect.hasCanonicalizer())
       os << canonicalizerDecl;
     if (dialect.hasConstantMaterializer())