sml VS llvm-project

Anyway the need is not complicated, I need both entry and exit functions from every state, optionally allowing these functions to be coroutines (that's special sauce but for later), and an explicit state transition table which also have a way to say that a state can be accessed at any point. Also allow states to be state machines, optional FSM hierarchies. If you ignore the coroutine stuff it's pretty standard features these days, except that - Boost.MSM is quite archaic now (it was so novel when it was first released...) although it allows most of the features I talked about, I just think it will complicate my code unneecessarilly; - Boost-Ext.SML (not Boost) is almost perfect except it doesnt have entry/exit functions on states for some reason. Also last time we (as in in livestream) tried it in prototypes it didnt compile on msvc XD - Boost-Ext.SML2 is even better but still doesnt have entry/exit functions although it's in the plans.

Hello all. Being a huge fan of state machine and coroutines, I have been browsing around for examples of what other people do combine these two. I have been using boost-ext/sml for quite many projects and are quite happy about that. But when transitioning to code that relies on coroutines, I would like to write entry/exit/actions/guard methods that uses coroutines and where I can co_await on awaitables from Asio and more recently "Boost Async".

boost-ext/sml: quite modern way of doing state machines using a DSL

I recently was troubleshooting a crash that backtraced through the boost::sml library [0]. The crash didn't actually have anything to do with the library, but it was used as the core event loop.

The backtrace -- as in, just the output from running `bt` in GDB -- was over a thousand wrapped lines long. There were ~5 stack frames that took up 200 lines of console each to print just the function name. That product's debug builds recently hit the 2GB line, which is enough that old versions of binutils complain.

I don't know what the solution is. There's some really neat stuff you can do with template metaprogramming, and in stripped release builds it compiles down extremely tiny. Plus the code is very clean to read. But it does feel like there isn't any kind of central vision for the C++ debugging experience, and bad interactions between highly-complex modern C++ typing, the compiler, and the debugger are probably only going to get worse unless somebody (the ISO committee? Vendors?) thinks really hard about debugging support.

[0]: https://github.com/boost-ext/sml

I'm a big fan of MSM but what you're experiencing is pretty normal for template-heavy libraries built on C++03 machinery (emulation of variadic templates is the usual culprit). It's probably not the answer you're hoping for, but the real solution is to switch to a library with more modern foundations. (I've been happily using [Boost::ext].SML for a few years but I'm reluctant to strongly recommend anything in particular since I haven't re-explored the problem space since I found it.)

The Boost one that you mention, seems to be one that it's kinda old. A "successor" of sorts is Boost SML. I've not used it yet, but certainly the first impressions are very good.

Or Boost.Sml

At our company, we rely a lot on https://github.com/boost-ext/sml

I'm a big fan of boost::sml for representing state machines.

https://github.com/boost-ext/sml (State Machine DSL and backend for perfomance)

'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...

See

https://github.com/llvm/llvm-project/issues/88344

https://fortran-lang.discourse.group/t/flang-new-how-to-forc...

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.

> 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...

> 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?

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...

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...

https://github.com/llvm/llvm-project/blob/main/flang/docs/F2...

• Go • Rust • Lua • pure C (sans C++) • 6502 assembly • WebAssembly • compiler backends, like LLVM or Cranelift