Emit the boilerplate for Type printer/parser dialect dispatching from…

… ODS

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

Differential Revision: https://reviews.llvm.org/D113332

mlir/include/mlir/Dialect/EmitC/IR/EmitCBase.td

@@ -29,6 +29,7 @@ def EmitC_Dialect : Dialect {
   }];
 
   let hasConstantMaterializer = 1;
+  let useDefaultTypePrinterParser = 1;
 }
 
 #endif // MLIR_DIALECT_EMITC_IR_EMITCBASE

mlir/include/mlir/IR/OpBase.td

@@ -302,6 +302,10 @@ class Dialect {
   // it'll dispatch the parsing to every individual attributes directly.
   bit useDefaultAttributePrinterParser = 0;
 
+  // If this dialect should use default generated type parser boilerplate:
+  // it'll dispatch the parsing to every individual types directly.
+  bit useDefaultTypePrinterParser = 0;
+
   // If this dialect overrides the hook for canonicalization patterns.
   bit hasCanonicalizer = 0;
 

mlir/include/mlir/TableGen/Dialect.h

@@ -78,6 +78,10 @@ class Dialect {
   /// attribute printing/parsing.
   bool useDefaultAttributePrinterParser() const;
 
+  /// Returns true if this dialect should generate the default dispatch for
+  /// type printing/parsing.
+  bool useDefaultTypePrinterParser() const;
+
   // Returns whether two dialects are equal by checking the equality of the
   // underlying record.
   bool operator==(const Dialect &other) const;

mlir/lib/Dialect/EmitC/IR/EmitC.cpp

@@ -227,25 +227,6 @@ Type emitc::OpaqueType::parse(DialectAsmParser &parser) {
   return get(parser.getContext(), value);
 }
 
-Type EmitCDialect::parseType(DialectAsmParser &parser) const {
-  llvm::SMLoc typeLoc = parser.getCurrentLocation();
-  StringRef mnemonic;
-  if (parser.parseKeyword(&mnemonic))
-    return Type();
-  Type genType;
-  OptionalParseResult parseResult =
-      generatedTypeParser(parser, mnemonic, genType);
-  if (parseResult.hasValue())
-    return genType;
-  parser.emitError(typeLoc, "unknown type in EmitC dialect");
-  return Type();
-}
-
-void EmitCDialect::printType(Type type, DialectAsmPrinter &os) const {
-  if (failed(generatedTypePrinter(type, os)))
-    llvm_unreachable("unexpected 'EmitC' type kind");
-}
-
 void emitc::OpaqueType::print(DialectAsmPrinter &printer) const {
   printer << "opaque<\"";
   llvm::printEscapedString(getValue(), printer.getStream());

mlir/lib/TableGen/Dialect.cpp

@@ -94,6 +94,10 @@ bool Dialect::useDefaultAttributePrinterParser() const {
   return def->getValueAsBit("useDefaultAttributePrinterParser");
 }
 
+bool Dialect::useDefaultTypePrinterParser() const {
+  return def->getValueAsBit("useDefaultTypePrinterParser");
+}
+
 Dialect::EmitPrefix Dialect::getEmitAccessorPrefix() const {
   int prefix = def->getValueAsInt("emitAccessorPrefix");
   if (prefix < 0 || prefix > static_cast<int>(EmitPrefix::Both))

mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp

@@ -528,6 +528,32 @@ void {0}::printAttribute(::mlir::Attribute attr,
 }
 )";
 
+/// The code block for default type parser/printer dispatch boilerplate.
+/// {0}: the dialect fully qualified class name.
+static const char *const dialectDefaultTypePrinterParserDispatch = R"(
+/// Parse a type registered to this dialect.
+::mlir::Type {0}::parseType(::mlir::DialectAsmParser &parser) const {{
+  llvm::SMLoc typeLoc = parser.getCurrentLocation();
+  StringRef mnemonic;
+  if (parser.parseKeyword(&mnemonic))
+    return Type();
+  Type genType;
+  OptionalParseResult parseResult =
+      generatedTypeParser(parser, mnemonic, genType);
+  if (parseResult.hasValue())
+    return genType;
+  parser.emitError(typeLoc) << "unknown  type `"
+      << mnemonic << "` in dialect `" << getNamespace() << "`";
+  return {{};
+}
+/// Print a type registered to this dialect.
+void {0}::printType(::mlir::Type type,
+                    ::mlir::DialectAsmPrinter &printer) const {{
+  if (succeeded(generatedTypePrinter(type, 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.
@@ -1020,6 +1046,12 @@ bool DefGenerator::emitDefs(StringRef selectedDialect) {
     os << llvm::formatv(dialectDefaultAttrPrinterParserDispatch,
                         defs.front().getDialect().getCppClassName());
 
+  // Emit the default parser/printer for Types if the dialect asked for it.
+  if (valueType == "Type" &&
+      defs.front().getDialect().useDefaultTypePrinterParser())
+    os << llvm::formatv(dialectDefaultTypePrinterParserDispatch,
+                        defs.front().getDialect().getCppClassName());
+
   return false;
 }
 

mlir/tools/mlir-tblgen/DialectGen.cpp

@@ -210,7 +210,7 @@ static void emitDialectDecl(Dialect &dialect,
     // add the hooks for parsing/printing.
     if (!dialectAttrs.empty() || dialect.useDefaultAttributePrinterParser())
       os << attrParserDecl;
-    if (!dialectTypes.empty())
+    if (!dialectTypes.empty() || dialect.useDefaultTypePrinterParser())
       os << typeParserDecl;
 
     // Add the decls for the various features of the dialect.