dmd VS llvm-project

Here's the pipeline spitting out the same error as on my macbook did.

https://github.com/dlang/dmd/actions/runs/8023469412/job/219...

Not completely on topic (if you read TFA) but my favorite Git commit is by compiler badass and HN frequenter, where he checks in an entire C compiler to the D language repo:

https://github.com/dlang/dmd/pull/12507

https://news.ycombinator.com/item?id=27102584

A new generated code alone is 4000 lines long [1]. The actual code added is just 2000 lines, and some are used to pay debts, I mean, to make a proper code generator (which can be alternatively written in a simpler scripting langauge). In any case it is never comparable to the entier C parser proper.

[1] https://github.com/dlang/dmd/pull/15307/files#diff-3677bcc89...

D is completely opensource already (https://github.com/dlang/dmd). The "open" of OpenD is just ADR saying that OpenD will be more open to new language features than D has historically been.

The reference compiler, DMD, is open source: https://github.com/dlang/dmd

But they don't accept just any Pull Request or features the community submits, understandably. There's a process called DIP for language improvements: https://github.com/dlang/DIPs/blob/master/DIPs/README.md

However, by some accounts, it's really hard to get anything through.

Given D already has so many feature, I find that to be a good thing , to be honest, by not everyone agrees, of course.

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

Compilers also may even spill data to stack from memory, even when the original location is still available, as can be seen in this issue: https://github.com/llvm/llvm-project/issues/53348

I vaguely remember that spilling like this could allow high-end CPUs to use something similar to register renaming, i.e. stack locations like [rsp + 96] could be stay in a physical registers during function execution (high-end CPUs often have more physical registers, than logical ones), but could find good references whether such optimization exists in practice or not.

Unfortunately, I think more often than note it causes performance regressions and in some cases it may even cause unnecessary stack spilling of sensitive data: https://github.com/rust-lang/rust/issues/88930#issuecomment-...