79 releases (15 breaking)

1.0.0-soon Sep 10, 2021
0.16.2 Sep 7, 2021
0.16.1 Aug 31, 2021
0.16.0-rc5 Jul 27, 2021
0.5.1 Nov 29, 2019

#9 in Magic Beans

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21K SLoC

CosmWasm VM

cosmwasm-vm on crates.io

This is an abstraction layer around the wasmer VM to expose just what we need to run cosmwasm contracts in a high-level manner. This is intended both for efficient writing of unit tests, as well as a public API to run contracts in eg. go-cosmwasm. As such it includes all glue code needed for typical actions, like fs caching.


A VM can support one or more contract-VM interface versions. The interface version is communicated by the contract via a Wasm import. This is the current compatibility list:

cosmwasm-vm Supported interface versions cosmwasm-std
1.0 TBD 1.0
0.16 interface_version_7 0.16
0.15 interface_version_6 0.15
0.14 interface_version_5 0.14
0.13 cosmwasm_vm_version_4 0.11-0.13
0.12 cosmwasm_vm_version_4 0.11-0.13
0.11 cosmwasm_vm_version_4 0.11-0.13
0.10 cosmwasm_vm_version_3 0.10
0.9 cosmwasm_vm_version_2 0.9
0.8 cosmwasm_vm_version_1 0.8

Changes between interface versions

interface_version_5 -> interface_version_6

  • Rename the fields from send to funds in WasmMsg::Instantiate and WasmMsg::Execute.
  • Merge messages and sub-messages.
  • Change JSON representation of IBC acknowledgements (#975).


There are demo files in testdata/*.wasm. Those are compiled and optimized versions of contracts/hackatom and contracts/staking run through rust-optimizer.

To rebuild the test contracts, go to the repo root and do

docker run --rm -v "$(pwd)":/code \
  --mount type=volume,source="devcontract_cache_hackatom",target=/code/contracts/hackatom/target \
  --mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
  cosmwasm/rust-optimizer:0.12.1 ./contracts/hackatom \
  && cp artifacts/hackatom.wasm packages/vm/testdata/hackatom_1.0.wasm

docker run --rm -v "$(pwd)":/code \
  --mount type=volume,source="devcontract_cache_ibc_reflect",target=/code/contracts/ibc-reflect/target \
  --mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
  cosmwasm/rust-optimizer:0.12.1 ./contracts/ibc-reflect \
  && cp artifacts/ibc_reflect.wasm packages/vm/testdata/ibc_reflect_1.0.wasm

docker run --rm -v "$(pwd)":/code \
  --mount type=volume,source="devcontract_cache_floaty",target=/code/contracts/floaty/target \
  --mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \
  cosmwasm/rust-optimizer:0.12.1 ./contracts/floaty \
  && cp artifacts/floaty.wasm packages/vm/testdata/floaty_1.0.wasm


By default, this repository is built and tested with the singlepass backend. You can enable the cranelift feature to override the default backend with Cranelift

cd packages/vm
cargo test --features iterator
cargo test --features cranelift,iterator


Using Singlepass:

cd packages/vm
cargo bench --no-default-features

Using Cranelift:

cd packages/vm
cargo bench --no-default-features --features cranelift


module_size and module_size.sh

Memory profiling of compiled modules. module_size.sh executes module_size, and uses valgrind's memory profiling tool (massif) to compute the amount of heap memory used by a compiled module.

cd packages/vm
RUSTFLAGS="-g" cargo build --release --example module_size
./examples/module_size.sh ./testdata/hackatom.wasm


This package is part of the cosmwasm repository, licensed under the Apache License 2.0 (see NOTICE and LICENSE).


~456K SLoC