Fix for CAF retention when dynamically loading & unloading code

In a situaion where we have some statically-linked code and we want to
load and unload a series of objects, we need the CAFs in the
statically-linked code to be retained indefinitely, while the CAFs in
the dynamically-linked code should be GC'd as normal, so that we can
detect when the code is unloadable.  This was wrong before - we GC'd
CAFs in the static code, leading to a crash in the rare case where we
use a CAF, GC it, and then load a new object that uses it again.

I also did some tidy up: RtsConfig now has a field keep_cafs to
indicate whether we want CAFs to be retained in static code.

1 files changed, 3 insertions, 3 deletions

diff --git a/rts/Linker.c b/rts/Linker.c
index 9d3ca1243e..bbf75bfd79 100644
--- a/rts/Linker.c
+++ b/rts/Linker.c
@@ -1512,7 +1512,7 @@ RTS_LIBFFI_SYMBOLS
 #define SymE_NeedsDataProto(vvv) SymE_HasDataProto(vvv)
 
 // SymI_HasProto_redirect allows us to redirect references to one symbol to
-// another symbol.  See newCAF/newDynCAF for an example.
+// another symbol.  See newCAF/newRetainedCAF/newGCdCAF for an example.
 #define SymI_HasProto_redirect(vvv,xxx)   \
     { MAYBE_LEADING_UNDERSCORE_STR(#vvv), \
       (void*)(&(xxx)) },
@@ -1692,10 +1692,10 @@ initLinker_ (int retain_cafs)
         barf("ghciInsertSymbolTable failed");
     }
 
-    // Redurect newCAF to newDynCAF if retain_cafs is true.
+    // Redurect newCAF to newRetainedCAF if retain_cafs is true.
     if (! ghciInsertSymbolTable(WSTR("(GHCi built-in symbols)"), symhash,
                                 MAYBE_LEADING_UNDERSCORE_STR("newCAF"),
-                                retain_cafs ? newDynCAF : newCAF,
+                                retain_cafs ? newRetainedCAF : newGCdCAF,
                                 HS_BOOL_FALSE, NULL)) {
         barf("ghciInsertSymbolTable failed");
     }