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Attempt to mutate residualized literal pair throws exception

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* libguile/validate.h (SCM_VALIDATE_MUTABLE_PAIR):
* libguile/pairs.h (scm_is_mutable_pair): New internal definitions.
* libguile/pairs.c (scm_set_car_x, scm_set_cdr_x): Validate mutable
  pairs.
* libguile/alist.c (scm_assq_set_x, scm_assv_set_x, scm_assoc_set_x):
* libguile/list.c (scm_reverse_x, scm_list_set_x, scm_list_cdr_set_x):
* libguile/srcprop.c (scm_make_srcprops):
* libguile/srfi-1.c (scm_srfi1_append_reverse_x)
  (scm_srfi1_delete_duplicates_x):
* libguile/symbols.c (scm_symbol_fset_x, scm_symbol_pset_x):
* libguile/sort.c (scm_merge_list_x): Use scm_set_car_x / scm_set_cdr_x
  instead of the macros, so as to check for mutable pairs.
  (SCM_VALIDATE_MUTABLE_LIST): New internal helper macro.
  (scm_sort_x, scm_stable_sort_x, scm_sort_list_x): Use
  SCM_VALIDATE_MUTABLE_LIST.
* libguile/vm-engine.c (VM_VALIDATE_MUTABLE_PAIR): New definition.
  (set-car!, set-cdr!): Use VM_VALIDATE_MUTABLE_PAIR.  Fix error message
  for set-cdr!.
This commit is contained in:
Andy Wingo 2017-04-17 11:26:17 +02:00
parent d7778b3d6a
commit 6e573a0885
11 changed files with 63 additions and 21 deletions
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16
libguile/pairs.h
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@ -176,6 +176,22 @@ scm_cdr (SCM x)
}
#endif
#ifdef BUILDING_LIBGUILE
static inline int
scm_is_mutable_pair (SCM x)
{
/* Guile embeds literal pairs into compiled object files. It's not
valid Scheme to mutate literal values. Two practical reasons to
enforce this restriction are to allow literals to share share
structure (pairs) with other literals in the compilation unit, and
to allow literals containing immediates to be allocated in the
read-only, shareable section of the file. Attempting to mutate a
pair in the read-only section would cause a segmentation fault, so
to avoid that, we really do need to enforce the restriction. */
return scm_is_pair (x) && GC_is_heap_ptr (SCM2PTR (x));
}
#endif /* BUILDING_LIBGUILE */
SCM_API SCM scm_cons2 (SCM w, SCM x, SCM y);
SCM_API SCM scm_pair_p (SCM x);
SCM_API SCM scm_set_car_x (SCM pair, SCM value);