diff --git a/compiler/GHC/Driver/Session.hs b/compiler/GHC/Driver/Session.hs index cd9e840cbbec511b19785dd77c7284c2f3646384..320cd1953ee5d381975b2638ed0733f91753176f 100644 --- a/compiler/GHC/Driver/Session.hs +++ b/compiler/GHC/Driver/Session.hs @@ -3341,7 +3341,17 @@ picCCOpts dflags = -- objects, but can't without -fPIC. See -- https://gitlab.haskell.org/ghc/ghc/wikis/commentary/position-independent-code | gopt Opt_PIC dflags || ways dflags `hasWay` WayDyn -> - ["-fPIC", "-U__PIC__", "-D__PIC__"] + ["-fPIC", "-U__PIC__", "-D__PIC__"] ++ + -- Clang defaults to -fvisibility=hidden for wasm targets, + -- but we need these compile-time flags to generate PIC + -- objects that can be properly linked by wasm-ld using + -- --export-dynamic; without these flags we would need + -- -Wl,--export-all at .so link-time which will export + -- internal symbols as well, and that severely pollutes the + -- global symbol namespace. + (if platformArch (targetPlatform dflags) == ArchWasm32 + then [ "-fvisibility=default", "-fvisibility-inlines-hidden" ] + else []) -- gcc may be configured to have PIC on by default, let's be -- explicit here, see #15847 | otherwise -> ["-fno-PIC"]