[Relay][VM] Allow to config allocator type and refactor vm code structure

docs/dev/virtual_machine.rst

@@ -321,7 +321,10 @@ VM Compiler
 
 An important part of this infrastructure is a compiler from Relay's full IR into a sequence of bytecode.
 The VM compiler transforms a ``tvm::relay::Module`` into a ``tvm::relay::vm::Executable``. The executable
-contains a set of compiled functions, the compiled functions are contained in ``tvm::relay::vm::Function``. The functions contain metadata about the function as well as its compiled bytecode. The emitted executable object then can be loaded and run by a ``tvm::relay::vm::VirtualMachine`` object. For full definitions of the data structures, please see `include/tvm/runtime/vm.h`_.
+contains a set of compiled functions, the compiled functions are contained in ``tvm::relay::vm::Function``.
+The functions contain metadata about the function as well as its compiled bytecode. The emitted executable
+object then can be loaded and run by a ``tvm::relay::vm::VirtualMachine`` object. For full definitions of the
+data structures, please see `include/tvm/runtime/executable.h`_ and `include/tvm/runtime/vm.h`_.
 
 Optimizations
 ~~~~~~~~~~~~~

include/tvm/relay/interpreter.h

@@ -38,7 +38,6 @@
 #include <tvm/relay/expr.h>
 #include <tvm/runtime/container.h>
 #include <tvm/runtime/object.h>
-#include <tvm/runtime/vm.h>
 #include <tvm/target/target.h>
 
 namespace tvm {
@@ -67,7 +66,7 @@ runtime::TypedPackedFunc<ObjectRef(Expr)> CreateInterpreter(IRModule mod, DLCont
                                                             Target target);
 
 /*! \brief The container type of Closures used by the interpreter. */
-class InterpreterClosureObj : public runtime::vm::ClosureObj {
+class InterpreterClosureObj : public runtime::ClosureObj {
  public:
   /*! \brief The set of free variables in the closure.
    *
@@ -89,13 +88,13 @@ class InterpreterClosureObj : public runtime::vm::ClosureObj {
   }
 
   static constexpr const char* _type_key = "interpreter.Closure";
-  TVM_DECLARE_FINAL_OBJECT_INFO(InterpreterClosureObj, runtime::vm::ClosureObj);
+  TVM_DECLARE_FINAL_OBJECT_INFO(InterpreterClosureObj, runtime::ClosureObj);
 };
 
-class InterpreterClosure : public runtime::vm::Closure {
+class InterpreterClosure : public runtime::Closure {
  public:
   TVM_DLL InterpreterClosure(tvm::Map<Var, ObjectRef> env, Function func);
-  TVM_DEFINE_OBJECT_REF_METHODS(InterpreterClosure, runtime::vm::Closure, InterpreterClosureObj);
+  TVM_DEFINE_OBJECT_REF_METHODS(InterpreterClosure, runtime::Closure, InterpreterClosureObj);
 };
 
 /*! \brief The container type of RecClosure. */

include/tvm/runtime/container.h

@@ -1671,6 +1671,23 @@ struct PackedFuncValueConverter<Optional<T>> {
   }
 };
 
+/*!
+ * \brief An object representing a closure. This object is used by both the
+ * Relay VM and interpreter.
+ */
+class ClosureObj : public Object {
+ public:
+  static constexpr const uint32_t _type_index = TypeIndex::kRuntimeClosure;
+  static constexpr const char* _type_key = "runtime.Closure";
+  TVM_DECLARE_BASE_OBJECT_INFO(ClosureObj, Object);
+};
+
+/*! \brief reference to closure. */
+class Closure : public ObjectRef {
+ public:
+  TVM_DEFINE_OBJECT_REF_METHODS(Closure, ObjectRef, ClosureObj);
+};
+
 }  // namespace runtime
 
 // expose the functions to the root namespace.