# Changelog

Documentation of all notable changes to the **EVMC** project.

The format is based on [Keep a Changelog],
and this project adheres to [Semantic Versioning].

## [6.3.0] - unreleased

### Added

- Experimental support for _Precompiles_ - 
  EVMC modules containing implementations of Ethereum precompiled contracts.
  To learn more read
  the [EVMC Precompiles](https://github.com/ethereum/evmc/issues/259) feature description.
  [[#267](https://github.com/ethereum/evmc/pull/267)]
- The `vm::get_capabilities()` method has been added in C++ API.
  [[#301](https://github.com/ethereum/evmc/pull/301)]
- A CMake helper for running evmc-vmtester.
  [[#303](https://github.com/ethereum/evmc/pull/303)]
- The loader module introduces standardized EVMC module configuration string 
  which contains path to the module and additional options.
  E.g. `./modules/vm.so,engine=compiler,trace,verbosity=2`.
  A VM can be loaded, created and configured atomically with 
  new `evmc_load_and_configure()` function.
  [[#313](https://github.com/ethereum/evmc/pull/313)]
- Full support for 32-bit architectures has been added.
  [[#327](https://github.com/ethereum/evmc/pull/327)]
- The C/C++ API for creating execution results in VMs has been extended 
  to handle common usage cases.
  [[#333](https://github.com/ethereum/evmc/pull/333)]
- Support for moving `evmc::vm` objects in C++ API.
  [[#341](https://github.com/ethereum/evmc/pull/341)]
- The basic types `address` and `bytes32` have received their C++ wrappers 
  to assure they are always initialized. 
  They also have convenient overloaded operators for comparison 
  and usage as keys in standard containers.
  [[#357](https://github.com/ethereum/evmc/pull/357)]
- The C++ EVMC basic types `address` and `bytes32` have user defined literals.
  [[#359](https://github.com/ethereum/evmc/pull/359)]
  ```cpp
  auto a = 0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359_address;
  auto b = 0xd4e56740f876aef8c010b86a40d5f56745a118d0906a34e69aec8c0db1cb8fa3_bytes32;
  ```
- CMake option `EVMC_INSTALL` (`ON` by default) to disable installing EVMC targets.
  This may be useful when EVMC is included in other project as git submodule or subtree.
  [[#360](https://github.com/ethereum/evmc/pull/360)]
- The `evmc-vmtester` tool received support for EVMC module configuration.
  E.g. `evmc-vmtester ./my_vm,mode=interpreter`.
  [[#366](https://github.com/ethereum/evmc/pull/366)]

### Changed

- A lot of documentation fixes, improvements and cleanups.
  [[#271](https://github.com/ethereum/evmc/pull/271),
   [#272](https://github.com/ethereum/evmc/pull/272),
   [#276](https://github.com/ethereum/evmc/pull/276),
   [#280](https://github.com/ethereum/evmc/pull/280),
   [#345](https://github.com/ethereum/evmc/pull/345)]
- In C++ API `evmc::result::raw()` renamed to `evmc::result::release_raw()`.
  [[#293](https://github.com/ethereum/evmc/pull/293)]
- In `evmc_load_and_create()` the `error_code` is optional (can be `NULL`).
  [[#311](https://github.com/ethereum/evmc/pull/311)]

### Deprecated
  
- The usage of `evmc/helpers.hpp` has been deprecated. Use `evmc/evmc.hpp`
  which provides the same features.
  [[#358](https://github.com/ethereum/evmc/pull/358)]
- The tracing API has been deprecated as there have been some design flaws discovered. 
  New API is expected to be introduced in future.
  [[#376](https://github.com/ethereum/evmc/pull/376)]

### Fixed

- The `vmtester` tool now builds with MSVC with `/std:c++17`.
  [[#261](https://github.com/ethereum/evmc/issues/261),
  [#263](https://github.com/ethereum/evmc/pull/263)]
- The `evmc_release_result()` helper has been fixed.
  [[#266](https://github.com/ethereum/evmc/issues/266),
   [#279](https://github.com/ethereum/evmc/pull/279)]
- The missing include guard in `evmc.hpp` has been fixed.
  [[#300](https://github.com/ethereum/evmc/pull/300)]
- A loaded VM with incompatible ABI version is now properly destroyed.
  [[#305](https://github.com/ethereum/evmc/issues/305),
   [#306](https://github.com/ethereum/evmc/pull/306)]


## [6.2.2] - 2019-05-16

### Fixed

- Compilation error of `evmc::result::raw()` in Visual Studio fixed.
  [[#281](https://github.com/ethereum/evmc/pull/281)]
- The `evmc::result`'s move assignment operator fixed.
  [[#282](https://github.com/ethereum/evmc/pull/282)]

## [6.2.1] - 2019-04-29

### Fixed

- Disallow implicit conversion from C++ `evmc::result` to `evmc_result` 
  causing unintendent premature releasing of resources.
  [[#256](https://github.com/ethereum/evmc/issues/256),
   [#257](https://github.com/ethereum/evmc/issues/257)]


## [6.2.0] - 2019-04-25

### Added

- CMake option `EVMC_TEST_TOOLS` to build evmc-vmtester without bothering with internal unit tests.
  [[#216](https://github.com/ethereum/evmc/pull/216)]
- The full C++ EVMC API for both VM and Host implementations.
  [[#217](https://github.com/ethereum/evmc/pull/217),
   [#226](https://github.com/ethereum/evmc/pull/226)]
- Initial and rough **bindings for Rust**.  It is possible to implement an
  EVMC VM in Rust utilising some helpers.
  [[#201](https://github.com/ethereum/evmc/pull/201),
   [#202](https://github.com/ethereum/evmc/pull/202),
   [#233](https://github.com/ethereum/evmc/pull/233)]
- Handling of DLL loading errors greatly improved by 
  new `evmc_last_error_msg()` function.
  [[#230](https://github.com/ethereum/evmc/pull/230),
   [#232](https://github.com/ethereum/evmc/pull/232)]

### Changed

- The minimum supported GCC version is 6 (bumped from undocumented version 4.8).
  [[#195](https://github.com/ethereum/evmc/pull/195)]
- Go bindings improved by introduction of the `TxContext` struct.
  [[#197](https://github.com/ethereum/evmc/pull/197)]
- A lot improvements to the `evmc-vmtester` tool.
  [[#221](https://github.com/ethereum/evmc/pull/221),
   [#234](https://github.com/ethereum/evmc/pull/234),
   [#238](https://github.com/ethereum/evmc/pull/238),
   [#241](https://github.com/ethereum/evmc/pull/241),
   [#242](https://github.com/ethereum/evmc/pull/242)]
- [Cable] upgraded to version 0.2.17.
  [[#251](https://github.com/ethereum/evmc/pull/251)]

### Deprecated

- The `EVMC_CONSTANTINOPLE2` revision name is deprecated, replaced with `EVMC_PETERSBURG`.
  [[#196](https://github.com/ethereum/evmc/pull/196)]


## [6.1.1] - 2019-02-13

### Added

- Documentation of elements of `evmc_revision`.
  [[#192](https://github.com/ethereum/evmc/pull/192)]

### Fixed 

- Fixed compilation with GCC 5 because of the "deprecated" attribute applied
  to an enum element.
  [[#190](https://github.com/ethereum/evmc/pull/190)]


## [6.1.0] - 2019-01-24

### Added

- The **Istanbul** EVM revision has been added.
  [[#174](https://github.com/ethereum/evmc/pull/174)]
- The `is_zero()` C++ helper for basic data types has been added.
  [[#182](https://github.com/ethereum/evmc/pull/182)]
- Reserved the post-Constantinople EVM revision number.
  [[#186](https://github.com/ethereum/evmc/pull/186)]
- The C++ wrappers for VM and execution result objects have been added.
  [[#187](https://github.com/ethereum/evmc/pull/187)]

### Deprecated

- The `EVMC_LATEST_REVISION` name has been deprecated, replaced with `EVMC_MAX_REVISION`.
  [[#184](https://github.com/ethereum/evmc/pull/184)]


## [6.0.2] - 2019-01-16

### Fixed

- Add missing salt argument for CREATE2 in Host in Go bindings.
  [[#179](https://github.com/ethereum/evmc/pull/179)]


## [6.0.1] - 2018-11-10

### Fixed

- Integration of EVMC as a CMake subproject is easier because 
  Hunter is not loaded unless building tests (`EVMC_TESTING=ON`) is requested.
  [[#169](https://github.com/ethereum/evmc/pull/169)]


## [6.0.0] - 2018-10-24

### Added

- [EVMC Host implementation example](https://github.com/ethereum/evmc/blob/master/examples/example_host.cpp).
  [[#116](https://github.com/ethereum/evmc/pull/116)]
- Support for Constantinople SSTORE net gas metering.
  [[#127](https://github.com/ethereum/evmc/pull/127)]
- Support for Constantinople CREATE2 salt in Go bindings.
  [[#133](https://github.com/ethereum/evmc/pull/133)]
- A VM can now report its **capabilities** (i.e. EVM and/or ewasm).
  [[#144](https://github.com/ethereum/evmc/pull/144)]
- Introduction of the `evmc_bytes32` type.
  [[#152](https://github.com/ethereum/evmc/pull/152)]
- [EVMC Host implementation guide](https://ethereum.github.io/evmc/hostguide.html).
  [[#159](https://github.com/ethereum/evmc/pull/159)]
- [EVMC VM implementation guide](https://ethereum.github.io/evmc/vmguide.html).
  [[#160](https://github.com/ethereum/evmc/pull/160)]

### Changed

- EVMC loader symbol searching has been generalized.
  [[#119](https://github.com/ethereum/evmc/pull/119)]
- The `evmc_context_fn_table` renamed to `evmc_host_interface`.
  [[#125](https://github.com/ethereum/evmc/pull/125)]
- The `evmc_message` fields reordered.
  [[#128](https://github.com/ethereum/evmc/pull/128)]
- The `evmc_set_option()` now returns more information about the failure cause.
  [[#136](https://github.com/ethereum/evmc/pull/136)]
- In C the `bool` type is used instead of `int` for true/false flags.
  [[#138](https://github.com/ethereum/evmc/pull/138),
   [#140](https://github.com/ethereum/evmc/pull/140)]
- Simplification of signatures of Host methods.
  [[#154](https://github.com/ethereum/evmc/pull/154)]


## [5.2.0] - 2018-08-28

### Added

- Use also "evmc_create" function name for loading EVMC DLLs.
  [[#81](https://github.com/ethereum/evmc/pull/81)]

### Changed

- Documentation improvements, including documentation for the VM Tester.
  [[#97](https://github.com/ethereum/evmc/pull/97),
   [#107](https://github.com/ethereum/evmc/pull/107)]

### Fixed

- The `evmc.h` header compatibility with C++98 fixed.
  [[#92](https://github.com/ethereum/evmc/pull/92)]
- Compilation and build configuration fixes.
  [[#93](https://github.com/ethereum/evmc/pull/93),
   [#103](https://github.com/ethereum/evmc/pull/103)]


## [5.1.0] - 2018-08-23

### Added

- **Go language bindings** for EVMC.
  [[#41](https://github.com/ethereum/evmc/pull/41)]
- New error codes.
  [[#56](https://github.com/ethereum/evmc/pull/56),
   [#62](https://github.com/ethereum/evmc/pull/62)]
- More helper functions.
  [[#67](https://github.com/ethereum/evmc/pull/67),
   [#68](https://github.com/ethereum/evmc/pull/68),
   [#70](https://github.com/ethereum/evmc/pull/70)]

### Changed

- Documentation has been extended.
  [[#58](https://github.com/ethereum/evmc/pull/58)]
- Optional Result Storage helper module has been separated.
  [[#59](https://github.com/ethereum/evmc/pull/59)]
- [Cable] upgraded to 0.2.11.
  [[#75](https://github.com/ethereum/evmc/pull/75)]
- The license changed from MIT to **Apache 2.0**.
  [[#77](https://github.com/ethereum/evmc/pull/77)]

### Fixed

- Go bindings: Properly handle unknown error codes.
  [[#72](https://github.com/ethereum/evmc/pull/72)]


## [5.0.0] - 2018-08-10

### Added

- List of status codes extended and reordered.
  [[#23](https://github.com/ethereum/evmc/pull/23),
   [#24](https://github.com/ethereum/evmc/pull/24)]
- VM Tracing API.
  [[#32](https://github.com/ethereum/evmc/pull/32)]
- The support library with **metrics tables for EVM1 instructions**.
  [[#33](https://github.com/ethereum/evmc/pull/33),
   [#34](https://github.com/ethereum/evmc/pull/34)]
- Ability to create EVMC CMake package.
  [[#35](https://github.com/ethereum/evmc/pull/35)]
- The loader support library for VM dynamic loading.
  [[#40](https://github.com/ethereum/evmc/pull/40)]
- Constantinople: Support for `CREATE2` instruction.
  [[#45](https://github.com/ethereum/evmc/pull/45)]
- Constantinople: Support for `EXTCODEHASH` instruction.
  [[#49](https://github.com/ethereum/evmc/pull/49)]
- Constantinople: Storage status is reported back from `evmc_set_storage()`.
  [[#52](https://github.com/ethereum/evmc/pull/52)]


[6.3.0]: https://github.com/ethereum/evmc/compare/v6.2.1...master
[6.2.2]: https://github.com/ethereum/evmc/releases/tag/v6.2.2
[6.2.1]: https://github.com/ethereum/evmc/releases/tag/v6.2.1
[6.2.0]: https://github.com/ethereum/evmc/releases/tag/v6.2.0
[6.1.1]: https://github.com/ethereum/evmc/releases/tag/v6.1.1
[6.1.0]: https://github.com/ethereum/evmc/releases/tag/v6.1.0
[6.0.2]: https://github.com/ethereum/evmc/releases/tag/v6.0.2
[6.0.1]: https://github.com/ethereum/evmc/releases/tag/v6.0.1
[6.0.0]: https://github.com/ethereum/evmc/releases/tag/v6.0.0
[5.2.0]: https://github.com/ethereum/evmc/releases/tag/v5.2.0
[5.1.0]: https://github.com/ethereum/evmc/releases/tag/v5.1.0
[5.0.0]: https://github.com/ethereum/evmc/releases/tag/v5.0.0

[Cable]: https://github.com/ethereum/cable
[Keep a Changelog]: https://keepachangelog.com/en/1.0.0/
[Semantic Versioning]: https://semver.org