Using Solang on the command line

The Solang compiler is run on the command line. The solidity source file names are provided as command line arguments; the output is an optimized WebAssembly or Solana SBF file which is ready for deployment on a chain, and an metadata file (also known as the abi).

The following targets are supported right now: Solana and Polkadot (via the contracts pallet runtime).

Solang supports auto-completion for multiple shells. Use solang shell-complete --help to learn whether your favorite shell is supported. If so, evaluate the output of solang shell-complete <SHELL> in order to activate it. Example installation with bash:

echo 'source <(solang shell-complete bash)' >> ~/.bashrc

Compiler Usage

solang compile [OPTIONS]… [SOLIDITY SOURCE FILE]…

This means that the command line is solang compile followed by any options described below, followed by one or more solidity source filenames.

Options:

-v, --verbose

Make the output more verbose. The compiler tell you what contracts have been found in the source, and what files are generated. Without this option Solang will be silent if there are no errors or warnings.

--target target

This takes one argument, which can either be solana or polkadot. The target must be specified.

--address-length length-in-bytes

Change the default address length on Polkadot. By default, Substate uses an address type of 32 bytes. This option is ignored for any other target.

--value-length length-in-bytes

Change the default value length on Polkadot. By default, Substate uses an value type of 16 bytes. This option is ignored for any other target.

-o, --output directory

Sets the directory where the output should be saved. This defaults to the current working directory if not set.

--output-meta directory

Sets the directory where metadata should be saved. For Solana, the metadata is the Anchor IDL file, and, for Polkadot, the .contract file. If this option is not set, the directory specified by --output is used, and if that is not set either, the current working directory is used.

--contract contract-name [, contract-name]…

Only compile the code for the specified contracts. If any those contracts cannot be found, produce an error.

-O optimization level

This takes one argument, which can either be none, less, default, or aggressive. These correspond to llvm optimization levels.

--importpath directory

When resolving import directives, search this directory. By default import will only search the current working directory. This option can be specified multiple times and the directories will be searched in the order specified.

--importmap map=directory

When resolving import directives, if the first part of the path matches map, search the directory provided for the file. This option can be specified multiple times with different values for map.

--help, -h

This displays a short description of all the options

--standard-json

This option causes Solang to emulate the behaviour of Solidity standard json output. No output files are written, all the output will be in json on stdout.

--emit phase

This option is can be used for debugging Solang itself. This is used to output early phases of compilation.

Phase:

ast-dot

Output Abstract Syntax Tree as a graphviz dot file. This can be viewed with xdot or any other tool that can visualize graphviz dot files.

cfg

Output control flow graph.

llvm-ir

Output llvm IR as text.

llvm-bc

Output llvm bitcode as binary file.

asm

Output assembly text file.

object

Output wasm object file; this is the contract before final linking.

--no-constant-folding

Disable the Constant Folding Pass codegen optimization

--no-strength-reduce

Disable the Strength Reduction Pass codegen optimization

--no-dead-storage

Disable the Dead Storage pass optimization

--no-vector-to-slice

Disable the Vector to Slice Pass optimization

--no-cse

Disable the Common Subexpression Elimination optimization

--no-log-runtime-errors

Disable the Log Runtime Errors debugging feature

--no-prints

Disable the Print Function debugging feature

--release

Disable all debugging features for Release builds:

--config-file

Read compiler configurations from a .toml file. The minimal fields required in the configuration file are:

[package]
input_files = ["flipper.sol"]  # Solidity files to compile

[target]
name = "solana"  # Target name

Fields not explicitly present in the .toml acquire the compiler’s default value. If any other argument is provided in the command line, for example, solang compile --config-file --target polkadot, the argument will be overridden. The priority for the args is given as follows: 1. Command line 2. Configuration file 3. Default values. The default name for the toml file is “solang.toml”. If two configuration files exist in the same directory, priority will be given to the one passed explicitly to this argument.

--wasm-opt

wasm-opt passes for Wasm targets (0, 1, 2, 3, 4, s or z; see the wasm-opt help for more details).

--contract-authors

Specify authors for all contracts. If a @author tag is present, it will override this argument for the targeted contract. For specifying multiple authors, use this format: –contract-authors author1,author2,..

Note

This will only affect the metadata in case of substrate target.

--version

Specify contracts version. According to semver, a normal version number must take the form X.Y.Z where X, Y, and Z are non-negative integers, and must not contain leading zeroes.

Warning

If multiple Solidity source files define the same contract name, you will get a single compiled contract file for this contract name. As a result, you will only have a single contract with the duplicate name without knowing from which Solidity file it originated. Solang will not give a warning about this problem.

Starting a new project

solang new --target solana my_project

A solang project is a directory in which there are one or more solidity files and a solang.toml file where the compilation options are defined. Given these two components, a user can run solang compile in a similar fashion as cargo build.

The solang new command creates a new solang project with an example flipper contract, and a default solang.toml configuration file.

Generating Documentation Usage

Generate documentation for the given Solidity files as a single html page. This uses the doccomment tags. The result is saved in soldoc.html. See Tags for further information.

solang doc [OPTIONS]… [SOLIDITY SOURCE FILE]…

This means that the command line is solang doc followed by any options described below, followed by one or more solidity source filenames.

Options:

--target target

This takes one argument, which can either be solana or polkadot. The target must be specified.

--address-length length-in-bytes

Change the default address length on Polkadot. By default, Substate uses an address type of 32 bytes. This option is ignored for any other target.

--value-length length-in-bytes

Change the default value length on Polkadot. By default, Substate uses an value type of 16 bytes. This option is ignored for any other target.

--importpath directory

When resolving import directives, search this directory. By default import will only search the current working directory. This option can be specified multiple times and the directories will be searched in the order specified.

--importmap map=directory

When resolving import directives, if the first part of the path matches map, search the directory provided for the file. This option can be specified multiple times with different values for map.

--help, -h

This displays a short description of all the options

Generate Solidity interface from IDL

This command converts Anchor IDL into Solidity import files, so they can be used to call Anchor Programs from Solidity.

solang idl [–output DIR] [IDLFILE]…

For each idl file provided, a Solidity file is written. See Calling Anchor Programs from Solidity for an example of how to use this.

Note

There is only supported on Solana.

Running Solang using a container

First pull the last Solang container from solang containers:

docker image pull ghcr.io/hyperledger/solang

And if you are using podman:

podman image pull ghcr.io/hyperledger/solang

Now you can run Solang like so:

docker run --rm -it ghcr.io/hyperledger/solang --version

Or podman:

podman container run --rm -it ghcr.io/hyperledger/solang --version

If you want to compile some Solidity files, the source files need to be available inside the container. You can do this via the -v docker command line. In this example /local/path should be replaced with the absolute path to your solidity files:

docker run --rm -it -v /local/path:/sources ghcr.io/hyperledger/solang compile -o /sources /sources/flipper.sol

On Windows, you need to specify absolute paths:

docker run --rm -it -v C:\Users\User:/sources ghcr.io/hyperledger/solang compile -o /sources /sources/flipper.sol