.. index:: ! installing
################################
Installing the Solidity Compiler
################################
Versioning
==========
Solidity versions follow `Semantic Versioning <https://semver.org>`_. In
addition, patch level releases with major release 0 (i.e. 0.x.y) will not
contain breaking changes. That means code that compiles with version 0.x.y
can be expected to compile with 0.x.z where z > y.
In addition to releases, we provide **nightly development builds** with the
intention of making it easy for developers to try out upcoming features and
provide early feedback. Note, however, that while the nightly builds are usually
very stable, they contain bleeding-edge code from the development branch and are
not guaranteed to be always working. Despite our best efforts, they might
contain undocumented and/or broken changes that will not become a part of an
actual release. They are not meant for production use.
When deploying contracts, you should use the latest released version of Solidity. This
is because breaking changes, as well as new features and bug fixes are introduced regularly.
We currently use a 0.x version number `to indicate this fast pace of change <https://semver.org/#spec-item-4>`_.
Remix
=====
*We recommend Remix for small contracts and for quickly learning Solidity.*
`Access Remix online <https://remix.ethereum.org/>`_, you do not need to install anything.
If you want to use it without connection to the Internet, go to
https://github.com/ethereum/remix-live/tree/gh-pages and download the ``.zip`` file as
explained on that page. Remix is also a convenient option for testing nightly builds
without installing multiple Solidity versions.
Further options on this page detail installing commandline Solidity compiler software
on your computer. Choose a commandline compiler if you are working on a larger contract
or if you require more compilation options.
.. _solcjs:
npm / Node.js
=============
Use ``npm`` for a convenient and portable way to install ``solcjs``, a Solidity compiler. The
`solcjs` program has fewer features than the ways to access the compiler described
further down this page. The
:ref:`commandline-compiler` documentation assumes you are using
the full-featured compiler, ``solc``. The usage of ``solcjs`` is documented inside its own
`repository <https://github.com/ethereum/solc-js>`_.
Note: The solc-js project is derived from the C++
`solc` by using Emscripten which means that both use the same compiler source code.
`solc-js` can be used in JavaScript projects directly (such as Remix).
Please refer to the solc-js repository for instructions.
.. code-block:: bash
npm install -g solc
.. note::
The commandline executable is named ``solcjs``.
The commandline options of ``solcjs`` are not compatible with ``solc`` and tools (such as ``geth``)
expecting the behaviour of ``solc`` will not work with ``solcjs``.
Docker
======
Docker images of Solidity builds are available using the ``solc`` image from the ``ethereum`` organisation.
Use the ``stable`` tag for the latest released version, and ``nightly`` for potentially unstable changes in the develop branch.
The Docker image runs the compiler executable, so you can pass all compiler arguments to it.
For example, the command below pulls the stable version of the ``solc`` image (if you do not have it already),
and runs it in a new container, passing the ``--help`` argument.
.. code-block:: bash
docker run ethereum/solc:stable --help
You can also specify release build versions in the tag, for example, for the 0.5.4 release.
.. code-block:: bash
docker run ethereum/solc:0.5.4 --help
To use the Docker image to compile Solidity files on the host machine mount a
local folder for input and output, and specify the contract to compile. For example.
.. code-block:: bash
docker run -v /local/path:/sources ethereum/solc:stable -o /sources/output --abi --bin /sources/Contract.sol
You can also use the standard JSON interface (which is recommended when using the compiler with tooling).
When using this interface it is not necessary to mount any directories as long as the JSON input is
self-contained (i.e. it does not refer to any external files that would have to be
:ref:`loaded by the import callback <initial-vfs-content-standard-json-with-import-callback>`).
.. code-block:: bash
docker run ethereum/solc:stable --standard-json < input.json > output.json
Linux Packages
==============
Binary packages of Solidity are available at
`solidity/releases <https://github.com/ethereum/solidity/releases>`_.
We also have PPAs for Ubuntu, you can get the latest stable
version using the following commands:
.. code-block:: bash
sudo add-apt-repository ppa:ethereum/ethereum
sudo apt-get update
sudo apt-get install solc
The nightly version can be installed using these commands:
.. code-block:: bash
sudo add-apt-repository ppa:ethereum/ethereum
sudo add-apt-repository ppa:ethereum/ethereum-dev
sudo apt-get update
sudo apt-get install solc
Furthermore, some Linux distributions provide their own packages. These packages are not directly
maintained by us, but usually kept up-to-date by the respective package maintainers.
For example, Arch Linux has packages for the latest development version:
.. code-block:: bash
pacman -S solidity
There is also a `snap package <https://snapcraft.io/solc>`_, however, it is **currently unmaintained**.
It is installable in all the `supported Linux distros <https://snapcraft.io/docs/core/install>`_. To
install the latest stable version of solc:
.. code-block:: bash
sudo snap install solc
If you want to help testing the latest development version of Solidity
with the most recent changes, please use the following:
.. code-block:: bash
sudo snap install solc --edge
.. note::
The ``solc`` snap uses strict confinement. This is the most secure mode for snap packages
but it comes with limitations, like accessing only the files in your ``/home`` and ``/media`` directories.
For more information, go to `Demystifying Snap Confinement <https://snapcraft.io/blog/demystifying-snap-confinement>`_.
macOS Packages
==============
We distribute the Solidity compiler through Homebrew
as a build-from-source version. Pre-built bottles are
currently not supported.
.. code-block:: bash
brew update
brew upgrade
brew tap ethereum/ethereum
brew install solidity
To install the most recent 0.4.x / 0.5.x version of Solidity you can also use ``brew install solidity@4``
and ``brew install solidity@5``, respectively.
If you need a specific version of Solidity you can install a
Homebrew formula directly from Github.
View
`solidity.rb commits on Github <https://github.com/ethereum/homebrew-ethereum/commits/master/solidity.rb>`_.
Copy the commit hash of the version you want and check it out on your machine.
.. code-block:: bash
git clone https://github.com/ethereum/homebrew-ethereum.git
cd homebrew-ethereum
git checkout <your-hash-goes-here>
Install it using ``brew``:
.. code-block:: bash
brew unlink solidity
# eg. Install 0.4.8
brew install solidity.rb
Static Binaries
===============
We maintain a repository containing static builds of past and current compiler versions for all
supported platforms at `solc-bin`_. This is also the location where you can find the nightly builds.
The repository is not only a quick and easy way for end users to get binaries ready to be used
out-of-the-box but it is also meant to be friendly to third-party tools:
- The content is mirrored to https://binaries.soliditylang.org where it can be easily downloaded over
HTTPS without any authentication, rate limiting or the need to use git.
- Content is served with correct `Content-Type` headers and lenient CORS configuration so that it
can be directly loaded by tools running in the browser.
- Binaries do not require installation or unpacking (with the exception of older Windows builds
bundled with necessary DLLs).
- We strive for a high level of backwards-compatibility. Files, once added, are not removed or moved
without providing a symlink/redirect at the old location. They are also never modified
in place and should always match the original checksum. The only exception would be broken or
unusable files with a potential to cause more harm than good if left as is.
- Files are served over both HTTP and HTTPS. As long as you obtain the file list in a secure way
(via git, HTTPS, IPFS or just have it cached locally) and verify hashes of the binaries
after downloading them, you do not have to use HTTPS for the binaries themselves.
The same binaries are in most cases available on the `Solidity release page on Github`_. The
difference is that we do not generally update old releases on the Github release page. This means
that we do not rename them if the naming convention changes and we do not add builds for platforms
that were not supported at the time of release. This only happens in ``solc-bin``.
The ``solc-bin`` repository contains several top-level directories, each representing a single platform.
Each one contains a ``list.json`` file listing the available binaries. For example in
``emscripten-wasm32/list.json`` you will find the following information about version 0.7.4:
.. code-block:: json
{
"path": "solc-emscripten-wasm32-v0.7.4+commit.3f05b770.js",
"version": "0.7.4",
"build": "commit.3f05b770",
"longVersion": "0.7.4+commit.3f05b770",
"keccak256": "0x300330ecd127756b824aa13e843cb1f43c473cb22eaf3750d5fb9c99279af8c3",
"sha256": "0x2b55ed5fec4d9625b6c7b3ab1abd2b7fb7dd2a9c68543bf0323db2c7e2d55af2",
"urls": [
"bzzr://16c5f09109c793db99fe35f037c6092b061bd39260ee7a677c8a97f18c955ab1",
"dweb:/ipfs/QmTLs5MuLEWXQkths41HiACoXDiH8zxyqBHGFDRSzVE5CS"
]
}
This means that:
- You can find the binary in the same directory under the name
`solc-emscripten-wasm32-v0.7.4+commit.3f05b770.js <https://github.com/ethereum/solc-bin/blob/gh-pages/emscripten-wasm32/solc-emscripten-wasm32-v0.7.4+commit.3f05b770.js>`_.
Note that the file might be a symlink, and you will need to resolve it yourself if you are not using
git to download it or your file system does not support symlinks.
- The binary is also mirrored at https://binaries.soliditylang.org/emscripten-wasm32/solc-emscripten-wasm32-v0.7.4+commit.3f05b770.js.
In this case git is not necessary and symlinks are resolved transparently, either by serving a copy
of the file or returning a HTTP redirect.
- The file is also available on IPFS at `QmTLs5MuLEWXQkths41HiACoXDiH8zxyqBHGFDRSzVE5CS`_.
- The file might in future be available on Swarm at `16c5f09109c793db99fe35f037c6092b061bd39260ee7a677c8a97f18c955ab1`_.
- You can verify the integrity of the binary by comparing its keccak256 hash to
``0x300330ecd127756b824aa13e843cb1f43c473cb22eaf3750d5fb9c99279af8c3``. The hash can be computed
on the command line using ``keccak256sum`` utility provided by `sha3sum`_ or `keccak256() function
from ethereumjs-util`_ in JavaScript.
- You can also verify the integrity of the binary by comparing its sha256 hash to
``0x2b55ed5fec4d9625b6c7b3ab1abd2b7fb7dd2a9c68543bf0323db2c7e2d55af2``.
.. warning::
Due to the strong backwards compatibility requirement the repository contains some legacy elements
but you should avoid using them when writing new tools:
- Use ``emscripten-wasm32/`` (with a fallback to ``emscripten-asmjs/``) instead of ``bin/`` if
you want the best performance. Until version 0.6.1 we only provided asm.js binaries.
Starting with 0.6.2 we switched to `WebAssembly builds`_ with much better performance. We have
rebuilt the older versions for wasm but the original asm.js files remain in ``bin/``.
The new ones had to be placed in a separate directory to avoid name clashes.
- Use ``emscripten-asmjs/`` and ``emscripten-wasm32/`` instead of ``bin/`` and ``wasm/`` directories
if you want to be sure whether you are downloading a wasm or an asm.js binary.
- Use ``list.json`` instead of ``list.js`` and ``list.txt``. The JSON list format contains all
the information from the old ones and more.
- Use https://binaries.soliditylang.org instead of https://solc-bin.ethereum.org. To keep things
simple we moved almost everything related to the compiler under the new ``soliditylang.org``
domain and this applies to ``solc-bin`` too. While the new domain is recommended, the old one
is still fully supported and guaranteed to point at the same location.
.. warning::
The binaries are also available at https://ethereum.github.io/solc-bin/ but this page
stopped being updated just after the release of version 0.7.2, will not receive any new releases
or nightly builds for any platform and does not serve the new directory structure, including
non-emscripten builds.
If you are using it, please switch to https://binaries.soliditylang.org, which is a drop-in
replacement. This allows us to make changes to the underlying hosting in a transparent way and
minimize disruption. Unlike the ``ethereum.github.io`` domain, which we do not have any control
over, ``binaries.soliditylang.org`` is guaranteed to work and maintain the same URL structure
in the long-term.
.. _IPFS: https://ipfs.io
.. _Swarm: https://swarm-gateways.net/bzz:/swarm.eth
.. _Solidity release page on github: https://github.com/ethereum/solidity/releases
.. _sha3sum: https://github.com/maandree/sha3sum
.. _WebAssembly builds: https://emscripten.org/docs/compiling/WebAssembly.html
.. _QmTLs5MuLEWXQkths41HiACoXDiH8zxyqBHGFDRSzVE5CS: https://gateway.ipfs.io/ipfs/QmTLs5MuLEWXQkths41HiACoXDiH8zxyqBHGFDRSzVE5CS
.. _16c5f09109c793db99fe35f037c6092b061bd39260ee7a677c8a97f18c955ab1: https://swarm-gateways.net/bzz:/16c5f09109c793db99fe35f037c6092b061bd39260ee7a677c8a97f18c955ab1/
Building from Source
====================
Prerequisites - All Operating Systems
-------------------------------------
The following are dependencies for all builds of Solidity:
+-----------------------------------+-------------------------------------------------------+
| Software | Notes |
+===================================+=======================================================+
| `CMake`_ (version 3.13+) | Cross-platform build file generator. |
+-----------------------------------+-------------------------------------------------------+
| `Boost`_ (version 1.77+ on | C++ libraries. |
| Windows, 1.65+ otherwise) | |
+-----------------------------------+-------------------------------------------------------+
| `Git`_ | Command-line tool for retrieving source code. |
+-----------------------------------+-------------------------------------------------------+
| `z3`_ (version 4.8+, Optional) | For use with SMT checker. |
+-----------------------------------+-------------------------------------------------------+
| `cvc4`_ (Optional) | For use with SMT checker. |
+-----------------------------------+-------------------------------------------------------+
.. _cvc4: https://cvc4.cs.stanford.edu/web/
.. _Git: https://git-scm.com/download
.. _Boost: https://www.boost.org
.. _CMake: https://cmake.org/download/
.. _z3: https://github.com/Z3Prover/z3
.. note::
Solidity versions prior to 0.5.10 can fail to correctly link against Boost versions 1.70+.
A possible workaround is to temporarily rename ``<Boost install path>/lib/cmake/Boost-1.70.0``
prior to running the cmake command to configure solidity.
Starting from 0.5.10 linking against Boost 1.70+ should work without manual intervention.
.. note::
The default build configuration requires a specific Z3 version (the latest one at the time the
code was last updated). Changes introduced between Z3 releases often result in slightly different
(but still valid) results being returned. Our SMT tests do not account for these differences and
will likely fail with a different version than the one they were written for. This does not mean
that a build using a different version is faulty. If you pass ``-DSTRICT_Z3_VERSION=OFF`` option
to CMake, you can build with any version that satisfies the requirement given in the table above.
If you do this, however, please remember to pass the ``--no-smt`` option to ``scripts/tests.sh``
to skip the SMT tests.
Minimum Compiler Versions
^^^^^^^^^^^^^^^^^^^^^^^^^
The following C++ compilers and their minimum versions can build the Solidity codebase:
- `GCC <https://gcc.gnu.org>`_, version 8+
- `Clang <https://clang.llvm.org/>`_, version 7+
- `MSVC <https://visualstudio.microsoft.com/vs/>`_, version 2019+
Prerequisites - macOS
---------------------
For macOS builds, ensure that you have the latest version of
`Xcode installed <https://developer.apple.com/xcode/download/>`_.
This contains the `Clang C++ compiler <https://en.wikipedia.org/wiki/Clang>`_, the
`Xcode IDE <https://en.wikipedia.org/wiki/Xcode>`_ and other Apple development
tools that are required for building C++ applications on OS X.
If you are installing Xcode for the first time, or have just installed a new
version then you will need to agree to the license before you can do
command-line builds:
.. code-block:: bash
sudo xcodebuild -license accept
Our OS X build script uses `the Homebrew <https://brew.sh>`_
package manager for installing external dependencies.
Here's how to `uninstall Homebrew
<https://docs.brew.sh/FAQ#how-do-i-uninstall-homebrew>`_,
if you ever want to start again from scratch.
Prerequisites - Windows
-----------------------
You need to install the following dependencies for Windows builds of Solidity:
+-----------------------------------+-------------------------------------------------------+
| Software | Notes |
+===================================+=======================================================+
| `Visual Studio 2019 Build Tools`_ | C++ compiler |
+-----------------------------------+-------------------------------------------------------+
| `Visual Studio 2019`_ (Optional) | C++ compiler and dev environment. |
+-----------------------------------+-------------------------------------------------------+
| `Boost`_ (version 1.77+) | C++ libraries. |
+-----------------------------------+-------------------------------------------------------+
If you already have one IDE and only need the compiler and libraries,
you could install Visual Studio 2019 Build Tools.
Visual Studio 2019 provides both IDE and necessary compiler and libraries.
So if you have not got an IDE and prefer to develop Solidity, Visual Studio 2019
may be a choice for you to get everything setup easily.
Here is the list of components that should be installed
in Visual Studio 2019 Build Tools or Visual Studio 2019:
* Visual Studio C++ core features
* VC++ 2019 v141 toolset (x86,x64)
* Windows Universal CRT SDK
* Windows 8.1 SDK
* C++/CLI support
.. _Visual Studio 2019: https://www.visualstudio.com/vs/
.. _Visual Studio 2019 Build Tools: https://www.visualstudio.com/downloads/#build-tools-for-visual-studio-2019
We have a helper script which you can use to install all required external dependencies:
.. code-block:: bat
scripts\install_deps.ps1
This will install ``boost`` and ``cmake`` to the ``deps`` subdirectory.
Clone the Repository
--------------------
To clone the source code, execute the following command:
.. code-block:: bash
git clone --recursive https://github.com/ethereum/solidity.git
cd solidity
If you want to help developing Solidity,
you should fork Solidity and add your personal fork as a second remote:
.. code-block:: bash
git remote add personal git@github.com:[username]/solidity.git
.. note::
This method will result in a prerelease build leading to e.g. a flag
being set in each bytecode produced by such a compiler.
If you want to re-build a released Solidity compiler, then
please use the source tarball on the github release page:
https://github.com/ethereum/solidity/releases/download/v0.X.Y/solidity_0.X.Y.tar.gz
(not the "Source code" provided by github).
Command-Line Build
------------------
**Be sure to install External Dependencies (see above) before build.**
Solidity project uses CMake to configure the build.
You might want to install `ccache`_ to speed up repeated builds.
CMake will pick it up automatically.
Building Solidity is quite similar on Linux, macOS and other Unices:
.. _ccache: https://ccache.dev/
.. code-block:: bash
mkdir build
cd build
cmake .. && make
or even easier on Linux and macOS, you can run:
.. code-block:: bash
#note: this will install binaries solc and soltest at usr/local/bin
./scripts/build.sh
.. warning::
BSD builds should work, but are untested by the Solidity team.
And for Windows:
.. code-block:: bash
mkdir build
cd build
cmake -G "Visual Studio 16 2019" ..
In case you want to use the version of boost installed by ``scripts\install_deps.ps1``, you will
additionally need to pass ``-DBoost_DIR="deps\boost\lib\cmake\Boost-*"`` and ``-DCMAKE_MSVC_RUNTIME_LIBRARY=MultiThreaded``
as arguments to the call to ``cmake``.
This should result in the creation of **solidity.sln** in that build directory.
Double-clicking on that file should result in Visual Studio firing up. We suggest building
**Release** configuration, but all others work.
Alternatively, you can build for Windows on the command-line, like so:
.. code-block:: bash
cmake --build . --config Release
CMake Options
=============
If you are interested what CMake options are available run ``cmake .. -LH``.
.. _smt_solvers_build:
SMT Solvers
-----------
Solidity can be built against SMT solvers and will do so by default if
they are found in the system. Each solver can be disabled by a `cmake` option.
*Note: In some cases, this can also be a potential workaround for build failures.*
Inside the build folder you can disable them, since they are enabled by default:
.. code-block:: bash
# disables only Z3 SMT Solver.
cmake .. -DUSE_Z3=OFF
# disables only CVC4 SMT Solver.
cmake .. -DUSE_CVC4=OFF
# disables both Z3 and CVC4
cmake .. -DUSE_CVC4=OFF -DUSE_Z3=OFF
The Version String in Detail
============================
The Solidity version string contains four parts:
- the version number
- pre-release tag, usually set to ``develop.YYYY.MM.DD`` or ``nightly.YYYY.MM.DD``
- commit in the format of ``commit.GITHASH``
- platform, which has an arbitrary number of items, containing details about the platform and compiler
If there are local modifications, the commit will be postfixed with ``.mod``.
These parts are combined as required by SemVer, where the Solidity pre-release tag equals to the SemVer pre-release
and the Solidity commit and platform combined make up the SemVer build metadata.
A release example: ``0.4.8+commit.60cc1668.Emscripten.clang``.
A pre-release example: ``0.4.9-nightly.2017.1.17+commit.6ecb4aa3.Emscripten.clang``
Important Information About Versioning
======================================
After a release is made, the patch version level is bumped, because we assume that only
patch level changes follow. When changes are merged, the version should be bumped according
to SemVer and the severity of the change. Finally, a release is always made with the version
of the current nightly build, but without the ``prerelease`` specifier.
Example:
1. The 0.4.0 release is made.
2. The nightly build has a version of 0.4.1 from now on.
3. Non-breaking changes are introduced --> no change in version.
4. A breaking change is introduced --> version is bumped to 0.5.0.
5. The 0.5.0 release is made.
This behaviour works well with the :ref:`version pragma <version_pragma>`.
