compiler/main/SysTools/BaseDir.hs¶
Note [topdir: How GHC finds its files]¶
GHC needs various support files (library packages, RTS etc), plus various auxiliary programs (cp, gcc, etc). It starts by finding topdir, the root of GHC’s support files
- On Unix:
- ghc always has a shell wrapper that passes a -B<dir> option
- On Windows:
ghc never has a shell wrapper.
- we can find the location of the ghc binary, which is
$topdir/<foo>/<something>.exe
where <something> may be “ghc”, “ghc-stage2”, or similar
we strip off the “<foo>/<something>.exe” to leave $topdir.
from topdir we can find package.conf, ghc-asm, etc.
Note [tooldir: How GHC finds mingw on Windows]
GHC has some custom logic on Windows for finding the mingw toolchain and perl. Depending on whether GHC is built with the make build system or Hadrian, and on whether we’re running a bindist, we might find the mingw toolchain and perl either under $topdir/../{mingw, perl}/ or $topdir/../../{mingw, perl}/.
