I've tried clang for windows twice. Each time the problem hasn't been the compiler, which works well, it has been which library to use with it on windows. Clang 5.0 worked well up until I needed the filesystem library, which isn't there. Does anyone know if it still relies on the visual studio C++ library?
Clang Is Now Used to Build Chrome for Windows
31–40 of 105 posts
Re: Clang Is Now Used to Build Chrome for Windows
#32> if your project is Windows-only, you can get a second compiler’s opinion on your code, and Clang’s warnings might find bugs GCC (mingw.org and mingw-w64 triples) has existed and been able to do this, including and especially cross-compiling, for a long time. No need to manually download a Windows SDK either. edited to add: to be fair, it's not ABI compatible with MSVC. But it deserves a mention and it's an easier o…
mingw-w64 llvm maintainer/developer here.
Over the past 2-3 years, with great help from a few other LLVM devs I have slowly pushed for native clang support for mingw-w64. With the current in tree HEAD you can now build and bootstrap mingw-w64 with a llvm-only toolchain (no binutils or gcc, thus no disregard of the PECOFF SPEC)
The stack is as follows. LLVM+CLANG+LLD+COMPILER-RT+LIBCXX+LIBCXXABI+LIBUNWIND+MINGW-W64.
The libraries and executables built this way can be dropped into visual studio quite easily, the two environments are now basically interchangeable. This also means we can borrow the PDB debugging work by Zachary Turner and/or any msvc features added to llvm for free that was done by the various googlers working on chrome. See a talk from Reid on the most recent LLVM developer meetup for more info on PDB and how it works. There has been no formal release of this environment yet but you should see something in the coming weeks/months. I keep build scripts here for those interested.
https://github.com/martell/mingw-w64-clang
I'm due another cleanup of the repo now that wine 3.0 is out so I can actually run x64 tests within a linux docker container. I'm going to be doing some blogging to make this more visible with various partners that want to support this.
The most interesting part of this for me was implementing a llvm-dlltool alternative to binutils dlltool that actually works within the PECOFF spec so msvc lib.exe and link.exe likes what it produces.
Re: Clang Is Now Used to Build Chrome for Windows
#33Last time I tried to build Chrome/Chromium I had to mess about with this build system called Ninja. (Which worked well it was just awkward to set up on Windows). Is that still in play?
Ninja is used because it's simple, multiplatform and very fast. The mainstream alternatives offer at most 2 out of 3.
"it's simple": yep, so much so that you inevitably need a meta-build system. In the context of Chrome, the build system only offers 2 out of 3.
Re: Clang Is Now Used to Build Chrome for Windows
#34And why not use mingw gcc? Do they find somthing wrong with it? Edit Mingw-w64 its quite nice and includes gcc without all stuff cgwin does.
1) ABI compatibility is not present. With clang-cl you can compile half of your object files with MSVC and half with clang-cl, and link them together. That's very powerful. You might be thinking "but who is really gonna do that anyway?" However, there is more to the ABI than just this. For example, consider what happens if you need to use Structured Exception Handling. Well, with GCC, you can't.
2) Debug Information. GCC does not emit PDBs, it emits DWARF. This means you cannot use Visual Studio to debug, you cannot use vTune or WPA to profile, you cannot use symbol / source servers.
3) There are licensing implications, GPL != BSD and it's easier to use BSD.
These are the main reasons. There are other reasons though, such as if the entire goal is to get down to 1 toolchain and that toolchain is X, then why would you waste your time converting Y to Z?
Re: Clang Is Now Used to Build Chrome for Windows
#35I've tried clang for windows twice. Each time the problem hasn't been the compiler, which works well, it has been which library to use with it on windows. Clang 5.0 worked well up until I needed the filesystem library, which isn't there. Does anyone know if it still relies on the visual studio C++ library?
clang-cl is just a compiler. It relies on VS to provide the C and C++ standard libraries. VS 2017 has the filesystem library and it should work with clang-cl 6.
Re: Clang Is Now Used to Build Chrome for Windows
#36Earlier quoted context omitted.
Ninja is used because it's simple, multiplatform and very fast. The mainstream alternatives offer at most 2 out of 3.
"it's simple": yep, so much so that you inevitably need a meta-build system. In the context of Chrome, the build system only offers 2 out of 3.
It's by design that you need a meta-build system. Ninja build files were not designed to be written by hand, not even ninja itself has hand written ninja files.
Re: Clang Is Now Used to Build Chrome for Windows
#37> if your project is Windows-only, you can get a second compiler’s opinion on your code, and Clang’s warnings might find bugs GCC (mingw.org and mingw-w64 triples) has existed and been able to do this, including and especially cross-compiling, for a long time. No need to manually download a Windows SDK either. edited to add: to be fair, it's not ABI compatible with MSVC. But it deserves a mention and it's an easier o…
mingw-w64 llvm maintainer/developer here. Over the past 2-3 years, with great help from a few other LLVM devs I have slowly pushed for native clang support for mingw-w64. With the current in tree HEAD you can now build and bootstrap mingw-w64 with a llvm-only toolchain (no binutils or gcc, thus no disregard of the PECOFF SPEC) The stack is as follows. LLVM+CLANG+LLD+COMPILER-RT+LIBCXX+LIBCXXABI+LIBUNWIND+MINGW-W64. T…
This sounds great, it's been a long time coming and I'm sure many people will appreciate being able to debug their mingw generated executables in Visual Studio.
I did all of the PDB stuff in LLVM, happy to help if you need it (ping me on the mailing list or IRC)
Re: Clang Is Now Used to Build Chrome for Windows
#38Re: Clang Is Now Used to Build Chrome for Windows
#39I didn't realize that clang is mostly a drop in replacement for cl, and matches the C++ abi. That in of itself is awesome.
clang isn't. clang-cl is (after years of work by the clang-cl team at Google). They had to do a lot of work, especially around PDB (symbol-file) generation.
More precisely:
clang-cl is a drop-in replacement for cl (even the command lines are the same).
But clang-cl is just a driver for clang, and it's still possible to get the ABI compatibility without clang-cl, but you have to know what you're doing and get the flags right.
Re: Clang Is Now Used to Build Chrome for Windows
#40And why not use mingw gcc? Do they find somthing wrong with it? Edit Mingw-w64 its quite nice and includes gcc without all stuff cgwin does.
Why use it? llvm is the future anyway and lots of players have a stake in it and contribute to it. In fact, there are way too many c++ compilers if you ask me. I would gladly accept a world where clang is the one and only.
>I would gladly accept a world where clang is the one and only.
And luckily you don’t have any saying in such matters.