compiler/GHC/Driver/Session.hs

@@ -3817,8 +3817,10 @@ validHoleFitsImpliedGFlags
 default_PIC :: Platform -> [GeneralFlag]
 default_PIC platform =
   case (platformOS platform, platformArch platform) of
-    (OSDarwin, ArchX86_64) -> [Opt_PIC]
-    (OSOpenBSD, ArchX86_64) -> [Opt_PIC] -- Due to PIE support in
+    (OSDarwin,  ArchX86_64)  -> [Opt_PIC]
+    (OSDarwin,  ArchAarch64) -> [Opt_PIC]
+    (OSLinux,   ArchAarch64) -> [Opt_PIC, Opt_ExternalDynamicRefs]
+    (OSOpenBSD, ArchX86_64)  -> [Opt_PIC] -- Due to PIE support in
                                          -- OpenBSD since 5.3 release
                                          -- (1 May 2013) we need to
                                          -- always generate PIC. See
@@ -5111,4 +5113,3 @@ initSDocContext dflags style = SDC
 -- | Initialize the pretty-printing options using the default user style
 initDefaultSDocContext :: DynFlags -> SDocContext
 initDefaultSDocContext dflags = initSDocContext dflags defaultUserStyle
-

rts/sm/Storage.c

@@ -1751,6 +1751,14 @@ AdjustorWritable allocateExec(W_ bytes, AdjustorExecutable *exec_ret)
 {
     AdjustorWritable writ;
     ffi_closure* cl;
+    // This check is necessary as we can't use allocateExec for anything *but*
+    // ffi_closures on ios/darwin on arm.  libffi does some heavy lifting to
+    // get around the X^W restrictions, and we can't just use this codepath
+    // to allocate generic executable space. For those cases we have to refer
+    // back to allocateWrite/markExec/freeWrite (see above.)
+    if (bytes != sizeof(ffi_closure)) {
+        barf("allocateExec: for ffi_closure only");
+    }
     ACQUIRE_SM_LOCK;
     cl = writ = ffi_closure_alloc((size_t)bytes, exec_ret);
     if (cl != NULL) {