diff options
| -rw-r--r-- | typd_mlc.c | 30 |
1 files changed, 26 insertions, 4 deletions
@@ -486,6 +486,14 @@ static complex_descriptor *get_complex_descr(word *addr, word nwords) return (complex_descriptor *)addr[nwords - 1]; } +#ifdef AO_HAVE_store_release +# define set_obj_descr(op, nwords, d) \ + AO_store_release((volatile AO_t *)(op) + (nwords) - 1, (AO_t)(d)) +#else +# define set_obj_descr(op, nwords, d) \ + (void)(((word *)(op))[(nwords) - 1] = (word)(d)) +#endif + STATIC mse * GC_array_mark_proc(word * addr, mse * mark_stack_ptr, mse * mark_stack_limit, word env GC_ATTR_UNUSED) @@ -612,7 +620,7 @@ GC_API GC_ATTR_MALLOC void * GC_CALL GC_malloc_explicitly_typed(size_t lb, /* It is not safe to use GC_size_map[lb] to compute lg here as */ /* the former might be updated asynchronously. */ lg = BYTES_TO_GRANULES(GC_size(op)); - op[GRANULES_TO_WORDS(lg) - 1] = d; + set_obj_descr(op, GRANULES_TO_WORDS(lg), d); GC_dirty(op + GRANULES_TO_WORDS(lg) - 1); REACHABLE_AFTER_DIRTY(d); return op; @@ -654,7 +662,7 @@ GC_API GC_ATTR_MALLOC void * GC_CALL if (NULL == op) return NULL; lg = BYTES_TO_GRANULES(GC_size(op)); } - ((word *)op)[GRANULES_TO_WORDS(lg) - 1] = d; + set_obj_descr(op, GRANULES_TO_WORDS(lg), d); GC_dirty((word *)op + GRANULES_TO_WORDS(lg) - 1); REACHABLE_AFTER_DIRTY(d); return op; @@ -669,6 +677,7 @@ GC_API GC_ATTR_MALLOC void * GC_CALL GC_calloc_explicitly_typed(size_t n, complex_descriptor *complex_descr; int descr_type; struct LeafDescriptor leaf; + DCL_LOCK_STATE; GC_ASSERT(GC_explicit_typing_initialized); descr_type = GC_make_array_descriptor((word)n, (word)lb, d, &simple_descr, @@ -695,7 +704,7 @@ GC_API GC_ATTR_MALLOC void * GC_CALL GC_calloc_explicitly_typed(size_t n, lg = BYTES_TO_GRANULES(GC_size(op)); if (descr_type == LEAF) { /* Set up the descriptor inside the object itself. */ - volatile struct LeafDescriptor * lp = + struct LeafDescriptor * lp = (struct LeafDescriptor *) (op + GRANULES_TO_WORDS(lg) - (BYTES_TO_WORDS(sizeof(struct LeafDescriptor)) + 1)); @@ -704,12 +713,25 @@ GC_API GC_ATTR_MALLOC void * GC_CALL GC_calloc_explicitly_typed(size_t n, lp -> ld_size = leaf.ld_size; lp -> ld_nelements = leaf.ld_nelements; lp -> ld_descriptor = leaf.ld_descriptor; - ((volatile word *)op)[GRANULES_TO_WORDS(lg) - 1] = (word)lp; + /* Hold the allocation lock while writing the descriptor word */ + /* to the object to ensure that the descriptor contents are */ + /* seen by GC_array_mark_proc as expected. */ + /* TODO: It should be possible to replace locking with the */ + /* atomic operations (with the release barrier here) but, in */ + /* this case, avoiding the acquire barrier in */ + /* GC_array_mark_proc seems to be tricky as GC_mark_some might */ + /* be invoked with the world running. */ + LOCK(); + op[GRANULES_TO_WORDS(lg) - 1] = (word)lp; + UNLOCK(); } else { # ifndef GC_NO_FINALIZATION size_t lw = GRANULES_TO_WORDS(lg); + LOCK(); op[lw - 1] = (word)complex_descr; + UNLOCK(); + GC_dirty(op + lw - 1); REACHABLE_AFTER_DIRTY(complex_descr); |