On Fri, 11 Apr 2025, Takashi Yano via Cygwin-apps wrote: > On Thu, 10 Apr 2025 12:45:06 -0700 (PDT) > Jeremy Drake wrote: > > We (@mati865 and I) just managed to get llvm/clang 20.1.2 building and > > targeting Cygwin over at MSYS2, and I was wondering if you had anyone > > interested in these patches to update the package(s) in Cygwin? I'm not > > particularly interested in taking on more responsibilities, but I guess I > > could take a look at this if nobody else wants to. > > > > MSYS2 package: > > https://github.com/msys2/MSYS2-packages/tree/master/llvm > > > > Note that we wound up punting on LLD support for Cygwin targets: there's > > currently no way to tell the difference in the LLD driver between Cygwin > > and MinGW targets, and trying to adapt to Cygwin broke the ability to use > > that LLD for MinGW cross-compiling. Given that it was all pretty hacky > > anyway, it seemed better to keep the working MinGW cross-compiling support > > than trade it in for still-somewhat-broken Cygwin support when we can just > > keep using GNU ld for the Cygwin target. > > Amazing! > > Now I am trying to build llvm for cygwin. For now, it fails with > ld: error: export ordinal too large: xxxxx > in dll linkage. > > If you could give me a suggestion, I would greatly appreciate it.
Are you using the patches and cmake options from https://github.com/msys2/MSYS2-packages/tree/master/llvm ? I noticed one (0101-hack-dynamically-resolve-G-include-dir.patch) has an "msys" that will need to be changed to "cygwin". The export ordinal too large error is because there are too many symbols for export-all-symbols to export from the DLLs (the DLL export table uses an unsigned short, so you only get 65535 exports). With GCC, it can only build static libraries, see https://github.com/msys2/MSYS2-packages/blob/4813abedafbbe1343ca287fded18b14f1f792198/llvm/PKGBUILD#L175-L189 Once you have clang built, you can use it to rebuild llvm with dynamic libs. Clang has a workaround that hooks up ELF-style visibility "hidden" to exclude symbols from auto-export, so there are not too many symbols for a DLL.
