type.h File Reference

IR/AST nodes for the unified type system in TVM. More...

#include <tvm/ir/source_map.h>
#include <tvm/node/node.h>
#include <tvm/runtime/container/array.h>
#include <tvm/runtime/data_type.h>
#include <tvm/runtime/object.h>
#include <string>

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Classes
class	tvm::TypeNode
	Type is the base type of all types. More...
class	tvm::Type
	Managed reference to TypeNode. More...
class	tvm::PrimTypeNode
	Primitive data types used in the low-level IR. More...
class	tvm::PrimType
class	tvm::PointerTypeNode
	Low-level raw pointer type. More...
class	tvm::PointerType
class	tvm::TupleTypeNode
	The type of tuple values. More...
class	tvm::TupleType
	Managed reference to TupleTypeNode. More...
class	tvm::FuncTypeNode
	Function type. More...
class	tvm::FuncType
	Managed reference to FuncTypeNode. More...

Namespaces
	tvm
	Performance counters for profiling via the PAPI library.

Functions
Type	tvm::VoidType ()
bool	tvm::IsVoidType (const Type &type)
	Check whether the tyep represents void. More...

Detailed Description

IR/AST nodes for the unified type system in TVM.

We use TVM's type system as the unified type system throughout the stack.

This file contains types that are common across IR variants.

Relation between Type and runtime::DataType

Besides Type, we also store a dtype field in the low-level PrimExpr. runtime::DataType(dtype) provides coarse grained type information during compile time and runtime. It is eagerly built in low-level expression construction and can be used for quick type checking in the low-level IR. For example, when an Expr's dtype is int32, we know for sure that its type is also int32.

On the other hand, Type provides more fine grained information. For example, a low level expression can have DataType::Handle() as its dtype and MemRef[float32] as its type. Types are usually lazily constructed via type checking, so they may not readily be available during IR construction.

The unified Type serves as a common bridge across IR dialects. For example, we require all the functions to have a type signature, which allow us to build cross dialect function calls.