Command Line Interface (CLI)

The CLI of zkvyper is designed with resemblance to the CLI of vyper. There are two input/output (I/O) modes in the zkvyper interface:

• Basic CLI
• Combined JSON

All toolkits using zkvyper must be operating in combined JSON mode and follow its specification. It will make the toolkits more robust and future-proof, as the combined JSON mode is the most versatile and used for the majority of popular projects.

This page focuses on the basic CLI mode. For more information on combined JSON, see this page.

Basic CLI

Basic CLI mode is the simplest way to compile a file with the source code.

To compile a basic Vyper contract, make sure that the vyper compiler is present in your environment and run the example.

The rest of this section describes the available CLI options and their usage. You may also check out zkvyper --help for a quick reference.

--vyper

Specifies the path to the vyper compiler. Useful when the vyper compiler is not available in the system path.

Usage:

zkvyper './Simple.vy' --vyper '/path/to/vyper'

Examples in the subsequent sections assume that vyper is installed and available in the system path. If you prefer specifying the full path to vyper, use the --vyper option with the examples below.

Input Files

zkvyper supports multiple input files. The following command compiles two Vyper files and prints the bytecode:

zkvyper './Simple.vy' './Complex.vy'

--format / -f

This option can be used for two purposes:

1. Switch to combined JSON mode.
2. Select the desired output in basic CLI mode.

In basic CLI mode, the following selectors are available:

Some data above is produced by vyper, whereas the rest is produced by zkvyper, as designated in the Source column.

Usage:

zkvyper './Simple.vy' --format 'ir_json,ast,abi,method_identifiers,layout,userdoc,devdoc,eravm_assembly,project_metadata'

Output:

Contract `/Users/hedgarmac/src/era-compiler-tester//tests/vyper/simple/default.vy`:
0x0000000100200190000000110000c13d0000000a001001980000001d0000613d...(truncated)
{"seq":[(truncated)]}
{"contract_name":"/Users/hedgarmac/src/era-compiler-tester/tests/vyper/simple/default.vy","ast":{(truncated)}}
[{"inputs":[],"name":"first","outputs":[{"name":"","type":"uint8"}],"stateMutability":"pure","type":"function"},{"inputs":[],"name":"second","outputs":[{"name":"","type":"uint256"}],"stateMutability":"pure","type":"function"}]
{"first()":"0x3df4ddf4","second()":"0x5a8ac02d"}
{}
{}
{}
Contract `/Users/hedgarmac/src/era-compiler-tester//tests/vyper/simple/default.vy` assembly:
        .text
        .file   "default.vy"
        .globl  __entry
__entry:
.func_begin0:
        and!    1, r2, r0
        jump.ne @.BB0_9
        and!    code[@CPI0_1], r1, r0
        jump.eq @.BB0_10
... (truncated)

Project metadata:
{"evm_version":"cancun","llvm_options":[],"optimizer_settings":"M3B3","source_code_hash":[147,242,126,144,(truncated),22,153,132,218],"source_version":"0.4.0","zk_version":"1.5.8"}

The output order above is fixed and cannot be changed by the order of the selectors in the --format argument:

1. Bytecode
2. LLL IR JSON
3. AST
4. ABI
5. Method identifiers
6. Layout
7. User documentation
8. Developer documentation
9. EraVM assembly
10. Project metadata

--output-dir

Specifies the output directory for build artifacts. Can only be used in basic CLI and combined JSON modes.

Usage in basic CLI mode:

zkvyper './Simple.vy' --output-dir './build/'
ls './build/'

Output:

default.vy.zbin

Usage in combined JSON mode:

zkvyper './Simple.vy' --format 'combined_json' --output-dir './build/'
ls './build/'

Output:

combined.json

--overwrite

Overwrites the output files if they already exist in the output directory. By default, zkvyper does not overwrite existing files.

Can only be used in combination with the --output-dir option.

Usage:

zkvyper './Simple.vy' --format 'combined_json' --output-dir './build/' --overwrite

If the --overwrite option is not specified and the output files already exist, zkvyper will print an error message and exit:

Refusing to overwrite an existing file "./build/combined.json" (use --overwrite to force).

--version

Prints the version of zkvyper and the hash of the LLVM commit it was built with.

Usage:

zkvyper --version

--help

Prints the help message.

Usage:

zkvyper --help

Other I/O Modes

To switch to combined JSON mode, use the --format option with the combined_json argument:

zkvyper './Simple.vy' --format 'combined_json'

The mode-altering CLI options are mutually exclusive. This means that only one of the options below can be enabled at a time:

• --format / -f
• --llvm-ir
• --eravm-assembly
• --disassemble

zkvyper Compilation Settings

The options in this section are only configuring the zkvyper compiler and do not affect the underlying vyper compiler.

--optimization / -O

Sets the optimization level of the LLVM optimizer. Available values are:

For most cases, it is fine to use the default value of 3. You should only use the level z if you are ready to deliberately sacrifice performance and optimize for size.

Large contracts may hit the EraVM or EVM bytecode size limit. In this case, it is recommended to use the --fallback-Oz option rather than set the z level.

--fallback-Oz

Sets the optimization level to z for contracts that failed to compile due to overrunning the bytecode size constraints.

Under the hood, this option automatically triggers recompilation of contracts with level z. Contracts that were successfully compiled with the original --optimization setting are not recompiled.

It is recommended to have this option always enabled to prevent compilation failures due to bytecode size constraints. There are no known downsides to using this option.

--metadata-hash

Specifies the hash function used for project metadata.

The following values are allowed:

The default value is keccak256.

EraVM requires its bytecode size to be an odd number of 32-byte words. If the size after appending the hash does not satisfy this requirement, the hash is prepended with zeros according to the Padding column in the table above.

Usage:

zkvyper './Simple.vy' --metadata-hash 'ipfs'

--suppress-warnings

Tells the compiler to suppress specified warnings. The option accepts multiple string arguments, so make sure they are properly separated by whitespace.

Only one warning can be suppressed with this option: txorigin.

Usage:

zkvyper './Simple.vy' --suppress-warnings 'txorigin'

--llvm-options

Specifies additional options for the LLVM framework. The argument must be a single quoted string following a = separator.

Usage:

zkvyper './Simple.vy' --llvm-options='-eravm-jump-table-density-threshold=10'

The --llvm-options option is experimental and must only be used by experienced users. All supported options will be documented in the future.

vyper Compilation Settings

The options in this section are only configuring vyper, so they are passed directly to its child process, and do not affect the zkvyper compiler.

--evm-version

Specifies the EVM version vyper will produce artifacts for. Only LLL IR is known to be affected by this option. For instance, if the EVM version is set to cancun, the LLL IR may contain mcopy instructions.

EVM version only affects IR artifacts produced by vyper and does not affect EraVM bytecode produced by zkvyper.

The following values are allowed by zkvyper:

• homestead
• tangerineWhistle
• spuriousDragon
• byzantium
• constantinople
• petersburg
• istanbul
• berlin
• london
• paris
• shanghai
• cancun
• prague

However, have in mind that many of them are not supported by vyper, or only supported by its newer versions. For instance, the --help message of vyper v0.4.0 only declares the following EVM versions as supported: london, paris, shanghai, cancun. For the full list of supported EVM versions, refer to the official vyper documentation.

Usage:

zkvyper './Simple.vy' --evm-version 'cancun'

--disable-vyper-optimizer

Disables the optimizer of the vyper compiler.

The optimizer is enabled by default for vyper v0.3.x. For vyper v0.4.x it is disabled and cannot be enabled, as the optimized LLL IR is not compatible with zkvyper.

zkvyper relies on the LLVM optimizer, so the vyper optimizer is not affecting the size or performance of the final bytecode significantly.

Usage:

zkvyper './Simple.vy' --disable-vyper-optimizer

--enable-decimals

Enables decimals in vyper v0.4.0.

Usage:

zkvyper './Simple.vy' --enable-decimals

--search-paths

Passes additional search paths to vyper.

Usage:

zkvyper './Simple.vy' --search-paths '/path/to/libraries-1/' '/path/to/libraries-2/'

Multi-Language Support

zkvyper supports input in multiple programming languages:

• Vyper
• LLVM IR
• EraVM assembly

The following sections outline how to use zkvyper with these languages.

--llvm-ir

Enables the LLVM IR mode. In this mode, input is expected to be in the LLVM IR language. The output works the same way as with Vyper input.

Unlike vyper, zkvyper is an LLVM-based compiler toolchain, so it uses LLVM IR as an intermediate representation. It is not recommended to write LLVM IR manually, but it can be useful for debugging and optimization purposes. LLVM IR is more low-level than Vyper LLL in the ZKsync compiler toolchain IR hierarchy, so vyper is not used for compilation.

Usage:

zkvyper --llvm-ir './Simple.ll'

Output:

Contract `<absolute-path>/Simple.ll`:
0x000000000002004b000000070000613d000000200100003900000000001004...

--eravm-assembly

Enables the EraVM Assembly mode. In this mode, input is expected to be in the EraVM assembly language. The output works the same way as with Vyper input.

EraVM assembly is a representation the closest to EraVM bytecode. It is not recommended to write EraVM assembly manually, but it can be even more useful for debugging and optimization purposes than LLVM IR.

For the EraVM assembly specification, visit the EraVM documentation.

Usage:

zkvyper --eravm-assembly './Simple.zasm'

Output:

Contract `<absolute-path>/Simple.zasm`:
0x000000000120008c000000070000613d00000020010000390000000000100435000000000001043500000005010000410000000c0001042e0000002a01000039000000000010043500000004010000410000000c0001042e0000000b000004320000000c0001042e0000000d00010430000000000000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000004000000000000000000000000043bbf1d8e1b7b1d452f006fe83028ba3b7853f9ea8a4635f4c584fe1dc6429b5

Integrated Tooling

zkvyper includes several tools provided by the LLVM framework out of the box, such as disassembler and linker. The following sections describe the usage of these tools.

--disassemble

Enables the disassembler mode.

zkvyper includes an LLVM-based disassembler that can be used to disassemble compiled bytecode.

The disassembler input must be files with a hexadecimal string. The disassembler output is a human-readable representation of the bytecode, also known as EraVM assembly.

Usage:

cat './input.zbin'

Output:

0x0000008003000039000000400030043f0000000100200190000000140000c13d00000000020...

zkvyper --disassemble './input.zbin'

Output:

File `input.zbin` disassembly:

       0: 00 00 00 80 03 00 00 39       add     128, r0, r3
       8: 00 00 00 40 00 30 04 3f       stm.h   64, r3
      10: 00 00 00 01 00 20 01 90       and!    1, r2, r0
      18: 00 00 00 14 00 00 c1 3d       jump.ne 20
      20: 00 00 00 00 02 01 00 19       add     r1, r0, r2
      28: 00 00 00 0b 00 20 01 98       and!    code[11], r2, r0
      30: 00 00 00 23 00 00 61 3d       jump.eq 35
      38: 00 00 00 00 01 01 04 3b       ldp     r1, r1

Debugging

--debug-output-dir

Specifies the directory to store intermediate build artifacts. The artifacts can be useful for debugging and research.

The directory is created if it does not exist. If artifacts are already present in the directory, they are overwritten.

The intermediate build artifacts can be:

Usage:

zkvyper './Simple.vy' --debug-output-dir './debug/'
ls './debug/'

Output:

<absolute-path-with-underscores>_Simple.vy.lll
<absolute-path-with-underscores>_Simple.vy.runtime.optimized.ll
<absolute-path-with-underscores>_Simple.vy.runtime.unoptimized.ll
<absolute-path-with-underscores>_Simple.vy.zasm

The output file name is constructed as follows: <AbsoluteContractPathWithUnderscores>_<ContractName>.<Modifiers>.<Extension>.

--llvm-verify-each

Enables the verification of the LLVM IR after each optimization pass. This option is useful for debugging and research purposes.

Usage:

zkvyper './Simple.vy' --llvm-verify-each

--llvm-debug-logging

Enables the debug logging of the LLVM IR optimization passes. This option is useful for debugging and research purposes.

Usage:

zkvyper './Simple.vy' --llvm-debug-logging