scip-clang VS llvm-project

Use clangd as a library downstream, instead of directly using Clang - This could've potentially worked, but the problem is that it adds one more layer of indirection for understanding and debugging, which isn't necessarily a win just to get some more code reuse. I've read through some of the clangd code to see if we should adjust our own code. E.g. this bug fix is based on how clangd handles unresolved dependent names: https://github.com/sourcegraph/scip-clang/pull/321

(I work on C++ indexing at Sourcegraph.)

As my colleague mentioned in a sibling comment, we have an existing indexer lsif-clang which supports C++. I just added a Chromium example to the lsif-clang README right now: (direct link) https://sourcegraph.com/github.com/chromium/chromium@cab0660...

We are also actively working on a new SCIP indexer which should support features like cross-repo references in the future. https://github.com/sourcegraph/scip-clang

Right now, Abseil doesn't have precise code navigation because no one has uploaded an index for it. In an ideal world, we would automatically have precise indexes for all the C++ code on Sourcegraph, but that's a hard problem because of the large variety in build systems, build configurations, and system dependencies that are often specified outside the build system.

As far as I know, libstdc++'s representation has two advantages:

First, it simplifies the implementation of `s.data()`, because you hold a pointer that invariably points to the first character of the data. The pointer-less version needs to do a branch there. Compare libstdc++ [1] to libc++ [2].

[1]: https://github.com/gcc-mirror/gcc/blob/065dddc/libstdc++-v3/...

[2]: https://github.com/llvm/llvm-project/blob/1a96179/libcxx/inc...

Basically libstdc++ is paying an extra 8 bytes of storage, and losing trivial relocatability, in exchange for one fewer branch every time you access the string's characters. I imagine that the performance impact of that extra branch is tiny, and massively confounded in practice by unrelated factors that are clearly on libc++'s side (e.g. libc++'s SSO buffer is 7 bytes bigger, despite libc++'s string object itself being smaller). But it's there.

The second advantage is that libstdc++ already did it that way, and to change it would be an ABI break; so now they're stuck with it. I mean, obviously that's not an "advantage" in the intuitive sense; but it's functionally equivalent to an advantage, in that it's a very strong technical answer to the question "Why doesn't libstdc++ just switch to doing it libc++'s way?"

This Ruby implementation is based on mruby and LLVM and it’s commercial software but cheap.

'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...