Streamline and fix vector-size checks

* src/alloc.c (VECTOR_ELTS_MAX): New constant.
(allocate_vectorlike): LEN now must be positive.  Assume LEN
is in range.  All callers changed.
(allocate_vector): Arg is now ptrdiff_t, not EMACS_INT.
All callers changed.  Return zero vector here, not in
allocate_vectorlike.
* src/lisp.h (make_uninit_vector): Simplify.
* src/xwidget.c (webkit_js_to_lisp):
Check for overflow in ptrdiff_t calculations.

1 files changed, 2 insertions, 7 deletions

diff --git a/src/lisp.h b/src/lisp.h
index 7e7dba631f3..77b8b63e196 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -3695,7 +3695,7 @@ build_string (const char *str)
 
 extern Lisp_Object pure_cons (Lisp_Object, Lisp_Object);
 extern void make_byte_code (struct Lisp_Vector *);
-extern struct Lisp_Vector *allocate_vector (EMACS_INT);
+extern struct Lisp_Vector *allocate_vector (ptrdiff_t);
 
 /* Make an uninitialized vector for SIZE objects.  NOTE: you must
    be sure that GC cannot happen until the vector is completely
@@ -3709,12 +3709,7 @@ extern struct Lisp_Vector *allocate_vector (EMACS_INT);
 INLINE Lisp_Object
 make_uninit_vector (ptrdiff_t size)
 {
-  Lisp_Object v;
-  struct Lisp_Vector *p;
-
-  p = allocate_vector (size);
-  XSETVECTOR (v, p);
-  return v;
+  return make_lisp_ptr (allocate_vector (size), Lisp_Vectorlike);
 }
 
 /* Like above, but special for sub char-tables.  */