(mark_object): Avoid car recursion on cons with nil in cdr.

Avoid recursion on constants-vector of a compiled function.

1 files changed, 33 insertions, 15 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 495c702d038..9cf149e51d1 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -1332,7 +1332,6 @@ mark_object (objptr)
     case Lisp_Window:
     case Lisp_Process:
     case Lisp_Window_Configuration:
-    case Lisp_Compiled:
       {
         register struct Lisp_Vector *ptr = XVECTOR (obj);
         register int size = ptr->size;
@@ -1350,6 +1349,30 @@ mark_object (objptr)
       }
       break;
 
+    case Lisp_Compiled:
+      /* We could treat this just like a vector, but it is better
+         to save the COMPILED_CONSTANTS element for last and avoid recursion
+         there.  */
+      {
+        register struct Lisp_Vector *ptr = XVECTOR (obj);
+        register int size = ptr->size;
+        struct Lisp_Vector *volatile ptr1 = ptr;
+        register int i;
+
+        if (size & ARRAY_MARK_FLAG) break;   /* Already marked */
+        ptr->size |= ARRAY_MARK_FLAG; /* Else mark it */
+        for (i = 0; i < size; i++)     /* and then mark its elements */
+          {
+            if (ptr != ptr1)
+              abort ();
+            if (i != COMPILED_CONSTANTS)
+              mark_object (&ptr->contents[i]);
+          }
+        objptr = &ptr->contents[COMPILED_CONSTANTS];
+        obj = *objptr;
+        goto loop;
+      }
+
 #ifdef MULTI_FRAME
     case Lisp_Frame:
       {
@@ -1371,19 +1394,6 @@ mark_object (objptr)
       break;
 #endif /* not MULTI_FRAME */
 
-#if 0
-    case Lisp_Temp_Vector:
-      {
-        register struct Lisp_Vector *ptr = XVECTOR (obj);
-        register int size = ptr->size;
-        register int i;
-
-        for (i = 0; i < size; i++)     /* and then mark its elements */
-          mark_object (&ptr->contents[i]);
-      }
-      break;
-#endif /* 0 */
-
     case Lisp_Symbol:
       {
         register struct Lisp_Symbol *ptr = XSYMBOL (obj);
@@ -1410,7 +1420,7 @@ mark_object (objptr)
       XMARK (XMARKER (obj)->chain);
       /* DO NOT mark thru the marker's chain.
          The buffer's markers chain does not preserve markers from gc;
-         instead, markers are removed from the chain when they are freed by gc. */
+         instead, markers are removed from the chain when freed by gc.  */
       break;
 
     case Lisp_Cons:
@@ -1420,6 +1430,14 @@ mark_object (objptr)
         register struct Lisp_Cons *ptr = XCONS (obj);
         if (XMARKBIT (ptr->car)) break;
         XMARK (ptr->car);
+        /* If the cdr is nil, avoid recursion for the car.  */
+        if (EQ (ptr->cdr, Qnil))
+          {
+            objptr = &ptr->car;
+            obj = ptr->car;
+            XUNMARK (obj);
+            goto loop;
+          }
         mark_object (&ptr->car);
         objptr = &ptr->cdr;
         obj = ptr->cdr;