From 9c222b9c1a7f91497a37567b4d7de3a511fff069 Mon Sep 17 00:00:00 2001
From: Paul Eggert
Date: Thu, 2 Dec 2021 19:01:33 -0800
Subject: Port to C compilers that lack size-0 arrays

The C standard does not allow size-zero arrays, so redo struct
Lisp_Subr to not use size-zero arrays when native compilation is
not being used.  Formerly, the code was using size-zero arrays (a
GNU C extension) to avoid using memory unnecessarily when
HAVE_NATIVE_COMP is not defined.  Replace this hack with the
more-traditional hack of putting the relevant members inside
‘#ifdef HAVE_NATIVE_COMP’.
* src/alloc.c (cleanup_vector, mark_object):
* src/comp.c (make_subr):
* src/data.c (Fsubr_native_lambda_list, Fsubr_native_comp_unit):
* src/eval.c (init_eval_once, funcall_lambda):
* src/lisp.h (SUBR_NATIVE_COMPILEDP, SUBR_NATIVE_COMPILED_DYNP)
(SUBR_TYPE):
* src/lread.c (Fload):
Conditionally compile with ‘#ifdef HAVE_NATIVE_COMP’ instead of
with ‘if (NATIVE_COMP_FLAG)’.  Redo members like native_comp_u[0]
to be plain native_comp_u.  Put all uses of these members inside
‘#ifdef HAVE_NATIVE_COMP’.
* src/lisp.h (struct Lisp_Subr): Members native_comp_u,
native_c_name, lambda_list, type are now all ifdeffed out if
HAVE_NATIVE_COMP is not defined, instead of being size-zero
arrays.  All uses changed.
* src/pdumper.c (dump_subr, dump_cold_native_subr)
(dump_do_dump_relocation):
* src/comp.h (NATIVE_COMP_FLAG): Remove; no longer needed.
---
 src/alloc.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

(limited to 'src/alloc.c')

diff --git a/src/alloc.c b/src/alloc.c
index 0c04d5cde05..e2184d7ba86 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3152,26 +3152,26 @@ cleanup_vector (struct Lisp_Vector *vector)
       module_finalize_function (function);
     }
 #endif
-  else if (NATIVE_COMP_FLAG
-	   && PSEUDOVECTOR_TYPEP (&vector->header, PVEC_NATIVE_COMP_UNIT))
+#ifdef HAVE_NATIVE_COMP
+  else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_NATIVE_COMP_UNIT))
     {
       struct Lisp_Native_Comp_Unit *cu =
 	PSEUDOVEC_STRUCT (vector, Lisp_Native_Comp_Unit);
       unload_comp_unit (cu);
     }
-  else if (NATIVE_COMP_FLAG
-	   && PSEUDOVECTOR_TYPEP (&vector->header, PVEC_SUBR))
+  else if (PSEUDOVECTOR_TYPEP (&vector->header, PVEC_SUBR))
     {
       struct Lisp_Subr *subr =
 	PSEUDOVEC_STRUCT (vector, Lisp_Subr);
-      if (!NILP (subr->native_comp_u[0]))
+      if (!NILP (subr->native_comp_u))
 	{
 	  /* FIXME Alternative and non invasive solution to this
 	     cast?  */
 	  xfree ((char *)subr->symbol_name);
-	  xfree (subr->native_c_name[0]);
+	  xfree (subr->native_c_name);
 	}
     }
+#endif
 }
 
 /* Reclaim space used by unmarked vectors.  */
@@ -6773,15 +6773,17 @@ mark_object (Lisp_Object arg)
 	    break;
 
 	  case PVEC_SUBR:
+#ifdef HAVE_NATIVE_COMP
 	    if (SUBR_NATIVE_COMPILEDP (obj))
 	      {
 		set_vector_marked (ptr);
 		struct Lisp_Subr *subr = XSUBR (obj);
 		mark_object (subr->native_intspec);
-		mark_object (subr->native_comp_u[0]);
-		mark_object (subr->lambda_list[0]);
-		mark_object (subr->type[0]);
+		mark_object (subr->native_comp_u);
+		mark_object (subr->lambda_list);
+		mark_object (subr->type);
 	      }
+#endif
 	    break;
 
 	  case PVEC_FREE:
-- 
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