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-rw-r--r--erts/emulator/beam/erl_gc.c45
1 files changed, 42 insertions, 3 deletions
diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index 67a73e4d57..7ab8034606 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -151,6 +151,7 @@ static void grow_new_heap(Process *p, Uint new_sz, Eterm* objv, int nobj);
static void sweep_off_heap(Process *p, int fullsweep);
static void offset_heap(Eterm* hp, Uint sz, Sint offs, char* area, Uint area_size);
static void offset_heap_ptr(Eterm* hp, Uint sz, Sint offs, char* area, Uint area_size);
+static void offset_heap_ptr_nstack(Eterm* hp, Uint sz, Sint offs, char* area, Uint area_size);
static void offset_rootset(Process *p, Sint offs, char* area, Uint area_size,
Eterm* objv, int nobj);
static void offset_off_heap(Process* p, Sint offs, char* area, Uint area_size);
@@ -1054,9 +1055,10 @@ erts_garbage_collect_hibernate(Process* p)
n_htop = tmp_n_htop; \
} while(0)
+
/*
* offset_nstack() can ignore the descriptor-based traversal the other
- * nstack procedures use and simply call offset_heap_ptr() instead.
+ * nstack procedures use and do a simpler word by word traversal instead.
* This relies on two facts:
* 1. The only live non-Erlang terms on an nstack are return addresses,
* and they will be skipped thanks to the low/high range check.
@@ -1071,14 +1073,51 @@ static ERTS_INLINE void offset_nstack(Process* p, Sint offs,
{
if (p->hipe.nstack) {
ASSERT(p->hipe.nsp && p->hipe.nstend);
- offset_heap_ptr(hipe_nstack_start(p), hipe_nstack_used(p),
- offs, area, area_size);
+ offset_heap_ptr_nstack(hipe_nstack_start(p), hipe_nstack_used(p),
+ offs, area, area_size);
}
else {
ASSERT(!p->hipe.nsp && !p->hipe.nstend);
}
}
+/*
+ * This is the same as offset_heap_ptr()
+ *
+ * Except for VALGRIND. It allows benign offsetting of undefined (dead) words
+ * on the nstack while also retaining them as undefined. This suppresses
+ * valgrinds "Conditional jump or move depends on uninitialised value(s)".
+ */
+static void
+offset_heap_ptr_nstack(Eterm* hp, Uint sz, Sint offs,
+ char* area, Uint area_size)
+{
+ while (sz--) {
+ Eterm val = *hp;
+#ifdef VALGRIND
+ Eterm val_vbits;
+ VALGRIND_GET_VBITS(&val, &val_vbits, sizeof(val));
+ VALGRIND_MAKE_MEM_DEFINED(&val, sizeof(val));
+#endif
+ switch (primary_tag(val)) {
+ case TAG_PRIMARY_LIST:
+ case TAG_PRIMARY_BOXED:
+ if (ErtsInArea(ptr_val(val), area, area_size)) {
+#ifdef VALGRIND
+ VALGRIND_SET_VBITS(&val, val_vbits, sizeof(val));
+#endif
+ *hp = offset_ptr(val, offs);
+ }
+ hp++;
+ break;
+ default:
+ hp++;
+ break;
+ }
+ }
+}
+
+
#else /* !HIPE */
#define fullsweep_nstack(p,n_htop) (n_htop)