CompCert
llvm-project
CompCert | llvm-project | |
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36 | 349 | |
1,763 | 25,563 | |
0.7% | 2.0% | |
7.2 | 10.0 | |
about 1 month ago | 6 days ago | |
Coq | C++ | |
GNU General Public License v3.0 or later | GNU General Public License v3.0 or later |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
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.
CompCert
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Differ: Tool for testing and validating transformed programs
A big problem is that proving that transformations preserve semantics is very hard. Formal methods has huge potential and I believe it will be a big part of the future, but it hasn't become mainstream yet. Probably a big reason why is that right now it's simply not practical: the things you can prove are much more limited than the things you can do, and it's a lot less work to just create a large testsuite.
Example: CompCert (https://compcert.org/), a formally-verified compiler AKA formally-verified sequence of semantics-preserving transformations from C code to Assembly. It's a great accomplishment, but few people are actually compiling their code with CompCert. Because GCC and LLVM are much faster[1], and have been used so widely that >99.9% of code is going to be compiled correctly, especially code which isn't doing anything extremely weird.
But as articles like this show, no matter how large a testsuite there may always be bugs, tests will never provide the kind of guarantees formal verification does.
[1] From CompCert, "Performance of the generated code is decent but not outstanding: on PowerPC, about 90% of the performance of GCC version 4 at optimization level 1"
- So you think you know C?
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Can the language of proof assistants be used for general purpose programming?
Also a C compiler (https://compcert.org/). I did exaggerate bit in saying that anything non-trivial is "nearly impossible".
However, both CompCert and sel4 took a few years to develop, whereas it would only take months if not weeks to make versions of both which aren't formally verified but heavily tested.
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A Guide to Undefined Behavior in C and C++
From my experience, while many MCUs have settled for the big compilers (GCC and Clang), DSPs and some FPGAs (not Intel and Xilinx, those have lately settled for Clang and a combination of Clang and GCC respectively) use some pretty bespoke compilers (just running ./ --version is enough to verify this, if the compiler even offers that option). That's not necessarily bad, since many of them offer some really useful features, but error messages can be really cryptic in some cases. Also some industries require use of verified compilers, like CompCert[1], and in such cases GCC and Clang just don't cut it.
[1]: https://compcert.org/
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Recently I am having too much friction with the borrow checker... Would you recommend I rewrite the compiler in another language, or keep trying to implement it in rust?
CompCert sends its regards
- Rosenpass – formally verified post-quantum WireGuard
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OpenAI might be training its AI technology to replace some software engineers, report says
But that's fine, because we can do even better with things like the CompCert C compiler, which is formally proven to produce correct asm output for ISO C 2011 source. It's designed for high-reliability, safety-critical applications; it's used for things like Airbus A380 avionics software, or control software for emergency generators at nuclear power plants. Software that's probably not overly sophisticated and doesn't need to be highly optimized, but does need to work ~100% correctly, ~100% of the time.
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There is such thing called bugfree code.
For context, CompCert is a formally verified compiler. My former advisor helped with a fuzzer called CSmith which found plenty of bugs in GCC and LLVM but not in CompCert.
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Checked C
Does anybody know how does this compare to https://compcert.org/ ?
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Proofs about Programs
This is a common property for proof-oriented languages. Coq shares this property for instance, and you can write an optimizing C compiler in Coq: https://github.com/AbsInt/CompCert .
llvm-project
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Ask HN: Which books/resources to understand modern Assembler?
'Computer Architeture: A Quantitative Apporach" and/or more specific design types (mips, arm, etc) can be found under the Morgan Kaufmann Series in Computer Architeture and Design.
"Getting Started with LLVM Core Libraries: Get to Grips With Llvm Essentials and Use the Core Libraries to Build Advanced Tools "
"The Architecture of Open Source Applications (Volume 1) : LLVM" https://aosabook.org/en/v1/llvm.html
"Tourist Guide to LLVM source code" : https://blog.regehr.org/archives/1453
llvm home page : https://llvm.org/
llvm tutorial : https://llvm.org/docs/tutorial/
llvm reference : https://llvm.org/docs/LangRef.html
learn by examples : C source code to 'llvm' bitcode : https://stackoverflow.com/questions/9148890/how-to-make-clan...
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Flang-new: How to force arrays to be allocated on the heap?
See
https://github.com/llvm/llvm-project/issues/88344
https://fortran-lang.discourse.group/t/flang-new-how-to-forc...
- The LLVM Compiler Infrastructure
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Programming from Top to Bottom - Parsing
You can never mistake type_declaration with an identifier, otherwise the program will not work. Aside from that constraint, you are free to name them whatever you like, there is no one standard, and each parser has it own naming conventions, unless you are planning to use something like LLVM. If you are interested, you can see examples of naming in different language parsers in the AST Explorer.
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Look ma, I wrote a new JIT compiler for PostgreSQL
> There is one way to make the LLVM JIT compiler more usable, but I fear it’s going to take years to be implemented: being able to cache and reuse compiled queries.
Actually, it's implemented in LLVM for years :) https://github.com/llvm/llvm-project/commit/a98546ebcd2a692e...
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C++ Safety, in Context
> It's true, this was a CVE in Rust and not a CVE in C++, but only because C++ doesn't regard the issue as a problem at all. The problem definitely exists in C++, but it's not acknowledged as a problem, let alone fixed.
Can you find a link that substantiates your claim? You're throwing out some heavy accusations here that don't seem to match reality at all.
Case in point, this was fixed in both major C++ libraries:
https://github.com/gcc-mirror/gcc/commit/ebf6175464768983a2d...
https://github.com/llvm/llvm-project/commit/4f67a909902d8ab9...
So what C++ community refused to regard this as an issue and refused to fix it? Where is your supporting evidence for your claims?
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Clang accepts MSVC arguments and targets Windows if its binary is named clang-cl
For everyone else looking for the magic in this almost 7k lines monster, look at line 6610 [1].
[1] https://github.com/llvm/llvm-project/blob/8ec28af8eaff5acd0d...
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Rewrite the VP9 codec library in Rust
Through value tracking. It's actually LLVM that does this, GCC probably does it as well, so in theory explicit bounds checks in regular C code would also be removed by the compiler.
How it works exactly I don't know, and apparently it's so complex that it requires over 9000 lines of C++ to express:
https://github.com/llvm/llvm-project/blob/main/llvm/lib/Anal...
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Fortran 2023
https://github.com/llvm/llvm-project/blob/main/flang/docs/F2...
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MiniScript Ports
• Go • Rust • Lua • pure C (sans C++) • 6502 assembly • WebAssembly • compiler backends, like LLVM or Cranelift
What are some alternatives?
seL4 - The seL4 microkernel
zig - General-purpose programming language and toolchain for maintaining robust, optimal, and reusable software.
coq - Coq is a formal proof management system. It provides a formal language to write mathematical definitions, executable algorithms and theorems together with an environment for semi-interactive development of machine-checked proofs.
Lark - Lark is a parsing toolkit for Python, built with a focus on ergonomics, performance and modularity.
unbound - Replib: generic programming & Unbound: generic treatment of binders
gcc
SDL - Simple Directmedia Layer
koika - A core language for rule-based hardware design 🦑
cosmopolitan - build-once run-anywhere c library
corn - Coq Repository at Nijmegen [maintainers=@spitters,@VincentSe]
windmill - Open-source developer platform to turn scripts into workflows and UIs. Fastest workflow engine (5x vs Airflow). Open-source alternative to Airplane and Retool.