* First pass on ADTs

* Add doc string for tag field

* Visit constructors in TypeVisitor for TypeData

* Add to description of type call

* Add type call to type solving and unification

* Make type mutator for typecall consistent with others (only create new node if there's a change)

* Ensure kindchecking can handle type calls and typedata

* Fix bad nesting in module constructor

* Correctly construct call in typecall test

* Add call override for ordinary vars (do we want this?)

* Remove generalization hack from type inference because it was breaking ADT constructors

* Check that there are no free type vars in exprs after inferring type

* Free var checks need module because of ADT constructors

* Typecall test can't have unbound type var, make it global

* Uncomment tmap test and remove comments about failing to infer ret type; those work now

* Put in dummy visits for ADTs in graph runtime codegen to placate pylint

* Fix Relay type infer test module constructor

* Mark override for TypeCallNode in type solver

* Ensure free vars check treats patern vars as bound

* Run interpreter in more ADT test cases

* Refactor kind check to return the kind, like typechecking

* Fix invalid typecall in test

* Add kind check to type inference, do not use nulls in func_type_annotation()!

* Redundant whitespace

* Make TypeData a separate kind

* Make ADT handles a separate kind too, document calling convention better

* Remove nats and tree from prelude, move to test, document prelude

* Restore and document nat and tree to prelude, add more tree tests

* Add alpha equality tests for match cases, fix variable binding bug

* Add more kind check tests for ADTs

* Add more tests for finding free or bound vars in match exprs

* Add unification tests for type call

* Update main() for alpha equality tests

* Add simple type inference test cases for match exprs and ADT constructors

* Add more ADT interpreter tests

* Allow incomplete types when typechecking match cases

* Type inference for pattern vars should use the type annotation if it's there

* Two more specific test cases for ADT matching

* Add option ADT to prelude

* Fix broken reference to kind enum

* Fix rebase snags

* Do not attach checked types to constructors

* More docstrings for module fields

* Use proper wrapper for indexing into module type data

* checked_type for constructors is not populated

* Expand type call docstring

* Rename PatternConstructor con field

* Use error reporter for pattern constructor case

* Condense error reporting in kind check, use error reporter

* Expand docstrings and rename ADT fields

* Rename 'option' ADT to 'optional' for consistency with Python

* Add various list iterators and utility functions to prelude

* Add smoke tests for new iterators in prelude

* Add concat to prelude

* Add smoke test for concat

* Correct docstrings in prelude

* Ensure that type defs are written in module initialization

* Various requested renamings

* Correct rebase snags

* Add kind check tests for ref types

* Update the main() for kind checking tests

Also enable Mul caching for more cases

This reverts commit 12d15704d7f5d30cff7540f1fd16be64c6baca68.

* [RUNTIME] Refactor extension type handling, now it is header only

* Make python BuildConfig serializable/deserializable to/from string

* Make C++ BuildConfig serializable/deserializable to/from string

* Revert "Make python BuildConfig serializable/deserializable to/from string"

This reverts commit a5e1fb3ff63a161cc0d63475d2a32816cc4c3666.

* Revert "Make C++ BuildConfig serializable/deserializable to/from string"

This reverts commit ec0c2c54543050fe6f264d06eebff33dee70370b.

* Converted BuildConfig to use TVM node system

* Fix lint

* Fix lint

* Added code to set node attributes through the C API

* Fixed bug in build_config()

* Fix lint

* Fix lint

* Fix test errors

* Reduced scope of node __setattr__ to apply only to BuildConfig

* Fix lint

* Fix lint

* Changed python BuildConfig to be immutable, with values set once on construction.

* Fix lint

* Fix C++ test

* Fixed BuildConfig setting python-side args

* Fix lint

* Removed dependency on reflection.cc to construct BuildConfig (allow use in runtime library)

* Fix lint

* Revert "Fix lint"

This reverts commit 16ed6d7a1ca5e551b035bad46e8361ea487cd45b.

* Revert "Removed dependency on reflection.cc to construct BuildConfig (allow use in runtime library)"

This reverts commit 43817c97a2ee045791e0c031d962fa97636ce8f6.

* Avoid accessing BuildConfig when using runtime lib

* Fix missing import

* Fix error running under cython (root cause: node handle is not valid until after __init__ has returned, so cannot call __dir__ during __init__

* Fix error where BuildConfig._node_defaults was not copied in build_config()

* Fix lint

* Fix lint

* Fix lint

* Fix lint

* Add comments to python BuildConfig

* Port build_module.py to C++

* Fix lint errors

* Fix more lint errors

* Fix more lint errors

* Fix more lint errors

* Fix build error

* Implemented style fixes

* Fix lint errors

* Added function to construct target from string
lower now returns array

* Fix lint error

* Implemented review changes - style & Target options -> std::vector

* Fixed lint, argument alignment and added unit test

* Changed test to target LLVM, fixed sign compare warnings

* Reverted unit test to CUDA, changed Jenkinsfile to enable GPU for C++ tests

* Slight change to Jenkinsfile

* Changed build_module test from CUDA to LLVM

* Added function var() to construct a Var instance.
Changed implementation of LLVMEnabled()

* Reverted Jenkinsfile

* [RUNTIME] Enable extension type to PackedFunc.

* More comments

* [TOPI] Move ewise.h -> elemwise.h

* fix test

* [OP] Initial start of op library

* add gtest

* [SCHEDULE] Add group, refactor thread bind api.

* fix doc

* fix g++-4.8

* More testscase

* Remove graph context from fix pt analysis

* [IterVar/REFACTOR] Add types to IterVar

* [ARITH/REFACTOR] Move IntSet to include

* [REFACTOR/OP] Move Op detail to seperate folder.

* fix test

* [ARITH/VISITOR] Modular Analysis, ExprFunctor, StmtFunctor

* retrigger

* [IRFunctor] Migrated CodegenC

* [IRFUNCTOR] Migrate CodeGenLLVM

* [IRFunctor] Migrate canonical

* [IRFunctor] Migrate vectorize

* [IRFunctor] migrate CodeGenStackVM