diff --git a/mlir/tools/mlir-tblgen/DialectGen.cpp b/mlir/tools/mlir-tblgen/DialectGen.cpp
--- a/mlir/tools/mlir-tblgen/DialectGen.cpp
+++ b/mlir/tools/mlir-tblgen/DialectGen.cpp
@@ -87,16 +87,9 @@
 ///
 /// {0}: The name of the dialect class.
 /// {1}: The dialect namespace.
-/// {2}: initialization code that is emitted in the ctor body before calling
-/// initialize()
 static const char *const dialectDeclBeginStr = R"(
 class {0} : public ::mlir::Dialect {
-  explicit {0}(::mlir::MLIRContext *context)
-    : ::mlir::Dialect(getDialectNamespace(), context,
-      ::mlir::TypeID::get<{0}>()) {{
-    {2}
-    initialize();
-  }
+  explicit {0}(::mlir::MLIRContext *context);
 
   void initialize();
   friend class ::mlir::MLIRContext;
@@ -190,23 +183,13 @@
                 const iterator_range<DialectFilterIterator> &dialectAttrs,
                 const iterator_range<DialectFilterIterator> &dialectTypes,
                 raw_ostream &os) {
-  /// Build the list of dependent dialects
-  std::string dependentDialectRegistrations;
-  {
-    llvm::raw_string_ostream dialectsOs(dependentDialectRegistrations);
-    for (StringRef dependentDialect : dialect.getDependentDialects())
-      dialectsOs << llvm::formatv(dialectRegistrationTemplate,
-                                  dependentDialect);
-  }
-
   // Emit all nested namespaces.
   {
     NamespaceEmitter nsEmitter(os, dialect);
 
     // Emit the start of the decl.
     std::string cppName = dialect.getCppClassName();
-    os << llvm::formatv(dialectDeclBeginStr, cppName, dialect.getName(),
-                        dependentDialectRegistrations);
+    os << llvm::formatv(dialectDeclBeginStr, cppName, dialect.getName());
 
     // Check for any attributes/types registered to this dialect.  If there are,
     // add the hooks for parsing/printing.
@@ -262,6 +245,19 @@
 // GEN: Dialect definitions
 //===----------------------------------------------------------------------===//
 
+/// The code block to generate a dialect constructor definition.
+///
+/// {0}: The name of the dialect class.
+/// {1}: initialization code that is emitted in the ctor body before calling
+///      initialize().
+static const char *const dialectConstructorStr = R"(
+{0}::{0}(::mlir::MLIRContext *context) 
+    : ::mlir::Dialect(getDialectNamespace(), context, ::mlir::TypeID::get<{0}>()) {{
+  {1}
+  initialize();
+}
+)";
+
 /// The code block to generate a default desturctor definition.
 ///
 /// {0}: The name of the dialect class.
@@ -271,16 +267,30 @@
 )";
 
 static void emitDialectDef(Dialect &dialect, raw_ostream &os) {
+  std::string cppClassName = dialect.getCppClassName();
+
   // Emit the TypeID explicit specializations to have a single symbol def.
   if (!dialect.getCppNamespace().empty())
     os << "MLIR_DEFINE_EXPLICIT_TYPE_ID(" << dialect.getCppNamespace()
-       << "::" << dialect.getCppClassName() << ")\n";
+       << "::" << cppClassName << ")\n";
 
   // Emit all nested namespaces.
   NamespaceEmitter nsEmitter(os, dialect);
 
+  /// Build the list of dependent dialects.
+  std::string dependentDialectRegistrations;
+  {
+    llvm::raw_string_ostream dialectsOs(dependentDialectRegistrations);
+    for (StringRef dependentDialect : dialect.getDependentDialects())
+      dialectsOs << llvm::formatv(dialectRegistrationTemplate,
+                                  dependentDialect);
+  }
+
+  // Emit the constructor and destructor.
+  os << llvm::formatv(dialectConstructorStr, cppClassName,
+                      dependentDialectRegistrations);
   if (!dialect.hasNonDefaultDestructor())
-    os << llvm::formatv(dialectDestructorStr, dialect.getCppClassName());
+    os << llvm::formatv(dialectDestructorStr, cppClassName);
 }
 
 static bool emitDialectDefs(const llvm::RecordKeeper &recordKeeper,