4 ms·

> Llvm regularly breaks the API As opposed to the stable GCC API? > cannot be bootstrapped Say what now?

• moonchild 5y ago
  > Llvm [...] stable GCC API In GCC, the compiler frontends are generally developed in parallel with, and distributed in parallel with the backend. There are some frontends which are distributed separately, but I expect that gcc-rs will be integrated into the mainline gcc source tree once complete. So it's not really an issue in practice. To put it another way: llvm api breakage doesn't affect clang, but it does affect other compilers using llvm. Gcc is like a BSD, while llvm is like linux (except that linux makes a commitment to compatibility which llvm does not).
• choeger 5y ago
  Llvm doesn't have a bootstrap target.
  • pertymcpert 5y ago
    What do you mean a bootstrap target? What specifically does gcc provide that clang doesn't?
    • choeger 5y ago
      GCC specifically has bootstrapping as a feature in the build system. They take care to document which older version of GCC is required to build a newer versions. If you pick a version that doesn't rely on C++ (4.x IIRC) you can compile GCC with a very small and general C compiler (tinycc or so). That helps to provide a chain of trust and also gives you access to a new platform if necessary. LLVM only offers cmake so you always need a (full-feature) C++ compiler to build it. That being said, GCC could make things better by providing a C-only entry point in modern releases, but it's still better than LLVM in that regard.
      • pertymcpert 5y ago
        I don't understand. You could just cross compile LLVM onto a new platform from another host arch. You don't need to have a very long sequence of bootstrap builds, just directly jump.