llvm-tutor
alive2
| llvm-tutor | alive2 | |
|---|---|---|
| 1 | 5 | |
| 2,716 | 681 | |
| - | 2.1% | |
| 6.4 | 9.3 | |
| 8 days ago | 6 days ago | |
| C++ | C++ | |
| MIT License | MIT License |
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For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
llvm-tutor
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What's your salary?
If you want a quick example of something you can do for educational purposes (but would be totally worthless for reality) I'd say go to llvm and implement your own instcombine pass. Follow this tutorial to learn the basics.
alive2
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CBMC: C bounded model checker. (2021)
Another problem with LLVM I’ve heard about is that it’s intermediate language or API or something is a moving, informally-specified target. People who know LLVM internals might weigh in on that claim. If true, it’s actually easier to target C or a subset of Rust just because it’s static and well-understood.
Two projects sought to mitigate these issues by going in different directions. One was a compiler backend that aimed to be easy to learn with well-specified IL. The other aimed to formalize LLVM’s IL.
http://c9x.me/compile/
https://github.com/AliveToolkit/alive2
There have also been typed, assembly languages to support verification from groups like FLINT. One can also compile language-specific analysis with a certified to LLVM IL compiler. Integrating pieces from different languages can have risks. That (IIRC) is being mitigated by people doing secure, abstract compilation.
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Basic SAT model of x86 instructions using Z3, autogenerated from Intel docs
You can use it to (mostly) validate small snippets are the same. See Alive2 for the application of Z3/formalization of programs as SMT for that [1]. As far as I'm aware there are some problems scaling up to arbitrarily sized programs due to a lack of formalization in higher level languages in addition to computational constraints. With a lot of time and effort it can be done though [2].
1. https://github.com/AliveToolkit/alive2
2. https://sel4.systems/
- John Regehr: Alive2 LLVM optims verification
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Verifying GCC optimizations using an SMT solver
Yeah, this kind of thing is nice.
Alive had been used for years (almost a decade actually) by people to verify LLVM instcombine transforms.
Alive2 (https://github.com/AliveToolkit/alive2) makes it easier to do the same with most optimization passes.
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Programming in Z3 by learning to think like a compiler
Alive/Alive2 [1] is one of the most famous frameworks for compiler transformation verification using BitVec logic
[1] https://github.com/AliveToolkit/alive2
What are some alternatives?
remill - Library for lifting machine code to LLVM bitcode
CrossHair - An analysis tool for Python that blurs the line between testing and type systems.
clang-tutor - A collection of out-of-tree Clang plugins for teaching and learning
klee - KLEE Symbolic Execution Engine
mcsema - Framework for lifting x86, amd64, aarch64, sparc32, and sparc64 program binaries to LLVM bitcode
recreational-rosette - Some fun examples of solving problems with symbolic execution
mcc - MicroC example compiler for Stephen Edward's PLT class, but in Haskell
zz - 🍺🐙 ZetZ a zymbolic verifier and tranzpiler to bare metal C
mewa - Compiler-compiler for writing compiler frontends with Lua
Symbolica - Symbolica's open-source symbolic execution engine. [Moved to: https://github.com/Symbolica/Symbolica]
buildit - Online demo without installing at - https://buildit.so/tryit
Cassius - A CSS specification and reasoning engine