## API Changes
### DataType to runtime
- Rationale: DataType is a runtime data structure
- PRs https://github.com/apache/incubator-tvm/pull/4560
- Rename all old reference of tvm::Type to DataType
- ExprNode.type -> ExprNode.dtype, Expr.type() -> Expr.dtype()
- Move type constructors as static function: Int(bits) -> DataType::Int(bits)
### Node Object Unification
- Rationale: remove a few redirected macros and alias, unify node and object
- PRs: https://github.com/apache/incubator-tvm/pull/4603
- NodeXYZ -> ObjectXYZ
- TVM_DEFINE_NODE_REF: define the class and TVM_DEFINE_OBJECT_REF_METHODS
### IRMutator/Visitor Functor Unification
- Rationale: Unify mutator and functor
- PRs: https://github.com/apache/incubator-tvm/pull/4607
https://github.com/apache/incubator-tvm/pull/4606
- Add ```#include``` for places that need mutator
- IRMutator: sub-class StmtMutator or StmtExprMutator instead
- IRVisitor: sub-class StmtVisitor or StmtExprVisitor instead
### TVM_REGISTER_API -> TVM_REGISTER_GLOBAL
- Rationale: remove indirection
- PR: https://github.com/apache/incubator-tvm/pull/4621
- Rename to TVM_REGISTER_GLOBAL in ```runtime/registry.h```
### SeqStmt
- Rationale: avoid nested recursion in long blocks
- PR https://github.com/apache/incubator-tvm/pull/4627
- Use SeqStmt instead to constructs sequences
### tir::Call.name -> op
- Use op(RelayExpr) to replace the string name. see
https://github.com/apache/incubator-tvm/pull/5863
- Remove the call_type field https://github.com/apache/incubator-tvm/pull/5937
### IRPrinter -> ReprPrinter
- Rationale: repr printer is shared across all variants in the stack
- PRs https://github.com/apache/incubator-tvm/pull/4622
https://github.com/apache/incubator-tvm/pull/4752
- Rename IRPrinter -> ReprPrinter
### set_body_typed
- Rationale: avoid duplication in terms of type signatures
- https://github.com/apache/incubator-tvm/pull/4623
- Remove type signature argument in set_body_typed
```c++
// before
TVM_REGISTER_GLOBAL("add")
.set_body_typed([](int x) { return x + 1; }
// after
TVM_REGISTER_GLOBAL("add")
.set_body_typed([](int x) { return x + 1; }
```
### Node suffix Convention
- Rationale: unify the naming convention throughout the codebase see also
https://github.com/apache/incubator-tvm/issues/4648
- PRs https://github.com/apache/incubator-tvm/pull/4649
- Add Node suffix to low level IR nodes
- Add ObjectRef classes to the TIR nodes
- https://github.com/apache/incubator-tvm/pull/5773
- https://github.com/apache/incubator-tvm/pull/5778
- https://github.com/apache/incubator-tvm/pull/5784
### tvm::Expr -> PrimExpr
- Rationale: the low-level expression is renamed to "primitive" expression in
order to bring more unifications.
- PR https://github.com/apache/incubator-tvm/pull/4669
- tvm::Expr -> PrimExpr, ExprHash/ExprEqual->ObjectHash/ObjectEqual,
VarExpr->Var
### Relay Type/Module/Op
- Rationale: unify type system, and module across the stack.
- PRs https://github.com/apache/incubator-tvm/pull/4616
https://github.com/apache/incubator-tvm/pull/4678
https://github.com/apache/incubator-tvm/pull/4699
- tvm/relay/module.h -> tvm/ir/module.h
- relay::Module -> IRModule
### New Subfolders and Namespaces
- ir: Common set of types and IR structures
- attrs.h -> ir/attrs.h https://github.com/apache/incubator-tvm/pull/4709
- arith: Arithmetic simplification and integer analysis
- arithmetic.h -> arith/analyzer.h arith/bound.h arith/int_set.h
arith/pattern.h
- https://github.com/apache/incubator-tvm/pull/4722
- target: Target dependent information and codegen
- target_info.h -> target/target_info.h
https://github.com/apache/incubator-tvm/pull/4721
- codegen.h -> target/codegen.h
https://github.com/apache/incubator-tvm/pull/4742
- te namespace: Tensor expression DSL(compute and schedule)
- Add namespace to compute/schedule
- operation.h -> te/operation.h
- schedule.h -> te/schedule.h
- schedule_pass.h -> te/schedule_pass.h
- tensor.h -> te/tensor.h
- https://github.com/apache/incubator-tvm/pull/4727,
https://github.com/apache/incubator-tvm/pull/4759
- tir namespace: tensor-level IR
- lowered_func.h,buffer.h,data_layout.h ->
tir/buffer.h,tir/data_layout.h,tir/lowered_func.h
- ir.h -> tir/expr.h, tir/stmt.h
- ir_functor_ext.h -> tir/expr_functor.h, tir/stmt_functor.h
- https://github.com/apache/incubator-tvm/pull/4740
### LoweredFunc
TIR uses IRModule as basic unit of transformation instead of LoweredFunc.
- https://github.com/apache/incubator-tvm/pull/5233
### ir_pass.h
- The IRModule->IRModule transformations are moved to tir/transform.h
- The IRModule->Analaysis result passes are moved to tir/analysis.h
### Simplify
- Simplify function is removed, use Analyzer in arith/analyzer.h instead
- https://github.com/apache/incubator-tvm/pull/5385
### BuildConfig
- BuildConfig-> PassContext
https://github.com/apache/incubator-tvm/pull/5668
### Runtime Misc
- ThreadScope::make -> ThreadScope::Create
- StorageScope:
