Improve fix for macroexp crash with debugging.

* lisp.h (ASET) [ENABLE_CHECKING]: Pay attention to
ARRAY_MARK_FLAG when checking subscripts, because ASET is
not supposed to be invoked from the garbage collector.
See Andreas Schwab in <http://bugs.gnu.org/12118#25>.
(gc_aset): New function, which is like ASET but can be
used in the garbage collector.
(set_hash_key, set_hash_value, set_hash_next, set_hash_hash)
(set_hash_index): Use it instead of ASET.

2 files changed, 26 insertions, 6 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 3ba80f69749..4aa0dcb022e 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,15 @@
+2012-08-03  Paul Eggert  <eggert@cs.ucla.edu>
+
+        Improve fix for macroexp crash with debugging (Bug#12118).
+        * lisp.h (ASET) [ENABLE_CHECKING]: Pay attention to
+        ARRAY_MARK_FLAG when checking subscripts, because ASET is
+        not supposed to be invoked from the garbage collector.
+        See Andreas Schwab in <http://bugs.gnu.org/12118#25>.
+        (gc_aset): New function, which is like ASET but can be
+        used in the garbage collector.
+        (set_hash_key, set_hash_value, set_hash_next, set_hash_hash)
+        (set_hash_index): Use it instead of ASET.
+
 2012-08-03  Eli Zaretskii  <eliz@gnu.org>
 
         Support symlinks on latest versions of MS-Windows.
diff --git a/src/lisp.h b/src/lisp.h
index 3d00f4dde78..e77b76005cd 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -608,7 +608,7 @@ clip_to_bounds (ptrdiff_t lower, EMACS_INT num, ptrdiff_t upper)
 /* The IDX==IDX tries to detect when the macro argument is side-effecting.  */
 #define ASET(ARRAY, IDX, VAL)   \
   (eassert ((IDX) == (IDX)),                            \
-   eassert ((IDX) >= 0 && (IDX) < (ASIZE (ARRAY) & ~ARRAY_MARK_FLAG)),  \
+   eassert ((IDX) >= 0 && (IDX) < ASIZE (ARRAY)),       \
    XVECTOR (ARRAY)->contents[IDX] = (VAL))
 
 /* Convenience macros for dealing with Lisp strings.  */
@@ -2356,33 +2356,41 @@ aref_addr (Lisp_Object array, ptrdiff_t idx)
 }
 
 LISP_INLINE void
+gc_aset (Lisp_Object array, ptrdiff_t idx, Lisp_Object val)
+{
+  /* Like ASET, but also can be used in the garbage collector.  */
+  eassert (0 <= idx && idx < (ASIZE (array) & ~ARRAY_MARK_FLAG));
+  XVECTOR (array)->contents[idx] = val;
+}
+
+LISP_INLINE void
 set_hash_key (struct Lisp_Hash_Table *h, ptrdiff_t idx, Lisp_Object val)
 {
-  ASET (h->key_and_value, 2 * idx, val);
+  gc_aset (h->key_and_value, 2 * idx, val);
 }
 
 LISP_INLINE void
 set_hash_value (struct Lisp_Hash_Table *h, ptrdiff_t idx, Lisp_Object val)
 {
-  ASET (h->key_and_value, 2 * idx + 1, val);
+  gc_aset (h->key_and_value, 2 * idx + 1, val);
 }
 
 LISP_INLINE void
 set_hash_next (struct Lisp_Hash_Table *h, ptrdiff_t idx, Lisp_Object val)
 {
-  ASET (h->next, idx, val);
+  gc_aset (h->next, idx, val);
 }
 
 LISP_INLINE void
 set_hash_hash (struct Lisp_Hash_Table *h, ptrdiff_t idx, Lisp_Object val)
 {
-  ASET (h->hash, idx, val);
+  gc_aset (h->hash, idx, val);
 }
 
 LISP_INLINE void
 set_hash_index (struct Lisp_Hash_Table *h, ptrdiff_t idx, Lisp_Object val)
 {
-  ASET (h->index, idx, val);
+  gc_aset (h->index, idx, val);
 }
 
 /* Defined in data.c.  */