unpoison / poison objects while walking the heap

This fixes some ASAN errors

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67405 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

internal.h

@@ -105,6 +105,7 @@ extern "C" {
 # define __asan_poison_memory_region(x, y)
 # define __asan_unpoison_memory_region(x, y)
 # define __asan_region_is_poisoned(x, y) 0
+# define poisoned_object_p(x) 0
 #endif
 
 #ifdef HAVE_SANITIZER_MSAN_INTERFACE_H
@@ -132,6 +133,15 @@ poison_object(VALUE obj)
     poison_memory_region(ptr, SIZEOF_VALUE);
 }
 
+#if __has_feature(address_sanitizer)
+static inline void *
+poisoned_object_p(VALUE obj)
+{
+    struct RVALUE *ptr = (void *)obj;
+    return __asan_region_is_poisoned(ptr, SIZEOF_VALUE);
+}
+#endif
+
 static inline void
 unpoison_memory_region(const volatile void *ptr, size_t size, bool malloc_p)
 {

iseq.c

@@ -1011,10 +1011,17 @@ remove_coverage_i(void *vstart, void *vend, size_t stride, void *data)
 {
     VALUE v = (VALUE)vstart;
     for (; v != (VALUE)vend; v += stride) {
+	void *ptr = poisoned_object_p(v);
+	unpoison_object(v, false);
+
 	if (rb_obj_is_iseq(v)) {
             rb_iseq_t *iseq = (rb_iseq_t *)v;
             ISEQ_COVERAGE_SET(iseq, Qnil);
 	}
+
+	if (ptr) {
+	    poison_object(v);
+	}
     }
     return 0;
 }
@@ -3156,9 +3163,16 @@ trace_set_i(void *vstart, void *vend, size_t stride, void *data)
 
     VALUE v = (VALUE)vstart;
     for (; v != (VALUE)vend; v += stride) {
+	void *ptr = poisoned_object_p(v);
+	unpoison_object(v, false);
+
 	if (rb_obj_is_iseq(v)) {
 	    rb_iseq_trace_set(rb_iseq_check((rb_iseq_t *)v), turnon_events);
 	}
+
+	if (ptr) {
+	    poison_object(v);
+	}
     }
     return 0;
 }