Sasha Gryaznov
a4dde28607
* fix misprints in doc comments * added global gas tracker variable and local gas fn * all exported functions of the module to accept a new param and to set the gas_left global to its value at their very start * make module support both gas metering methods * tests fixed for the old metering method * better naming * MutableGlobal metering method implemented, tests for the old method pass * gas_metering::tests updated and pass * all tests udpdated and pass * emacs backup files to .gitignore * docs updated * clippy fix * iff = if and only if * more clippy * docs misprints fixes * refactored to have Backend trait and two implementations in separate sub-modules * docs updated * fixed old benches (updating them is coming next) * added bench for an instrumented wasm-coremark * updated benches: added them for both gas_metering instrumentations * benches contest first ver * added debug prints to the bench * refactored to better fit frontend-backend pattern * docs update * updated benches * design updated on feedback * re-structured sub-modules re-structured sub-modules & updated docs * docs improved * addressed latest feedback comments * re-writed the local gas function * coremark benches show ~20% performance improvement * fix ci: test + clippy * save before re-factoring prepare_in_wasm() * bare_call_16 shows 16% worse perf * + fibonacci recursive bench * refactored benchmarks * + factorial recursive bench * benches on wasmi fixtures show no perf improvement, coremark runs ~20% faster being instrumented with mutable_global gas metering * charge gas for local gas func isntructions execution * replaced benchmark which requires multi_value feature * save: optimized gas func a bit (benches work, fixture tests fail) * 1033% overhead on many_blocks.wasm when mut_global gas_metering together with stack_height * size overhead test for both gas metering methods + stack limiter * added more benches * improved print_size_overhead test * test for comparing size overheads of two gas_metering injectors * before optimization: benches + size overhead * optimization try-1: inline part of gas func instructions: +benches +size overheads * optimization try-2: inline hot path of gas fn: +benches +size overheads * opt try-3: count for gas fn cost on the caller side: +benches +size overhead * revert to initial version but with static gas fn cost on the caller side: +benches +sizes * tests fixed * use newest wasmi 0.20: +benches +docs updated * use if-else block instead of Return: +benches * fix tests * clippy fix * addressed review comments * Update changelog Co-authored-by: Alexander Theißen <alex.theissen@me.com>
wasm-instrument
A Rust library containing a collection of wasm module instrumentations and transformations mainly useful for wasm based block chains and smart contracts.
Provided functionality
This is a non exhaustive list of provided functionality. Please check out the documentation for details.
Gas Metering
Add gas metering to your platform by injecting the necessary code directly into the wasm module. This allows having a uniform gas metering implementation across different execution engines (interpreters, JIT compilers).
Stack Height Limiter
Neither the wasm standard nor any sufficiently complex execution engine specifies how many items on the wasm stack are supported before the execution aborts or malfunctions. Even the same execution engine on different operating systems or host architectures could support a different number of stack items and be well within its rights.
This is the kind of indeterminism that can lead to consensus failures when used in a blockchain context.
To address this issue we can inject some code that meters the stack height at runtime and aborts the execution when it reaches a predefined limit. Choosing this limit suffciently small so that it is smaller than what any reasonably parameterized execution engine would support solves the issue: All execution engines would reach the injected limit before hitting any implementation specific limitation.
License
wasm-instrument is distributed under the terms of both the MIT license and the
Apache License (Version 2.0), at your choice.
See LICENSE-APACHE, and LICENSE-MIT for details.
Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in wasm-instrument by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.