On Darwin add allocator address and size fields to

`sanitizer_malloc_introspection_t` and initialize them to zero.

We allow sanitizer implementations to perform different initialization
by defining `COMMON_MALLOC_HAS_EXTRA_INTROSPECTION_INIT` to be `1`
and providing an implementation of `mi_extra_init(...)`.

We use these changes in future patches to implement malloc zone enumeration.

rdar://problem/45284065

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@351712 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 25 insertions, 0 deletions

diff --git a/lib/sanitizer_common/sanitizer_malloc_mac.inc b/lib/sanitizer_common/sanitizer_malloc_mac.inc
index 344daac07..3f3581eeb 100644
--- a/lib/sanitizer_common/sanitizer_malloc_mac.inc
+++ b/lib/sanitizer_common/sanitizer_malloc_mac.inc
@@ -39,6 +39,8 @@ struct sanitizer_malloc_introspection_t : public malloc_introspection_t {
   // Used to track changes to the allocator that will affect
   // zone enumeration.
   u64 allocator_enumeration_version;
+  uptr allocator_ptr;
+  uptr allocator_size;
 };
 
 u64 GetMallocZoneAllocatorEnumerationVersion() {
@@ -303,6 +305,26 @@ kern_return_t mi_enumerator(task_t task, void *, unsigned type_mask,
 }
 #endif
 
+#ifndef COMMON_MALLOC_HAS_EXTRA_INTROSPECTION_INIT
+#error "COMMON_MALLOC_HAS_EXTRA_INTROSPECTION_INIT must be defined"
+#endif
+static_assert((COMMON_MALLOC_HAS_EXTRA_INTROSPECTION_INIT) == 0 ||
+                  (COMMON_MALLOC_HAS_EXTRA_INTROSPECTION_INIT) == 1,
+              "COMMON_MALLOC_HAS_EXTRA_INTROSPECTION_INIT must be 0 or 1");
+#if COMMON_MALLOC_HAS_EXTRA_INTROSPECTION_INIT
+// Forward declare and expect the implementation to provided by
+// includer.
+void mi_extra_init(
+    sanitizer_malloc_introspection_t *mi);
+#else
+void mi_extra_init(
+    sanitizer_malloc_introspection_t *mi) {
+  // Just zero initialize the fields.
+  mi->allocator_ptr = 0;
+  mi->allocator_size = 0;
+}
+#endif
+
 size_t mi_good_size(malloc_zone_t *zone, size_t size) {
   // I think it's always safe to return size, but we maybe could do better.
   return size;
@@ -361,6 +383,9 @@ void InitMallocZoneFields() {
   sanitizer_zone_introspection.allocator_enumeration_version =
       GetMallocZoneAllocatorEnumerationVersion();
 
+  // Perform any sanitizer specific initialization.
+  mi_extra_init(&sanitizer_zone_introspection);
+
   internal_memset(&sanitizer_zone, 0, sizeof(malloc_zone_t));
 
   // Use version 6 for OSX >= 10.6.