diff options
Diffstat (limited to 'compiler/cbits/keepCAFsForGHCi.c')
| -rw-r--r-- | compiler/cbits/keepCAFsForGHCi.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/compiler/cbits/keepCAFsForGHCi.c b/compiler/cbits/keepCAFsForGHCi.c index ba635b0d95..9645f54c9b 100644 --- a/compiler/cbits/keepCAFsForGHCi.c +++ b/compiler/cbits/keepCAFsForGHCi.c @@ -1,15 +1,35 @@ #include <Rts.h> +#include <ghcversion.h> +// Note [keepCAFsForGHCi] +// ~~~~~~~~~~~~~~~~~~~~~~ // This file is only included in the dynamic library. // It contains an __attribute__((constructor)) function (run prior to main()) // which sets the keepCAFs flag in the RTS, before any Haskell code is run. // This is required so that GHCi can use dynamic libraries instead of HSxyz.o // files. +// +// For static builds we have to guarantee that the linker loads this object file +// to ensure the constructor gets run and not discarded. If the object is part of +// an archive and not otherwise referenced the linker would ignore the object. +// To avoid this: +// * When initializing a GHC session in initGhcMonad we assert keeping cafs has been +// enabled by calling keepCAFsForGHCi. +// * This causes the GHC module from the ghc package to carry a reference to this object +// file. +// * Which in turn ensures the linker doesn't discard this object file, causing +// the constructor to be run, allowing the assertion to succeed in the first place +// as keepCAFs will have been set already during initialization of constructors. -static void keepCAFsForGHCi(void) __attribute__((constructor)); -static void keepCAFsForGHCi(void) + +bool keepCAFsForGHCi(void) __attribute__((constructor)); + +bool keepCAFsForGHCi(void) { - keepCAFs = 1; + bool was_set = keepCAFs; + setKeepCAFs(); + return was_set; } + |