Index: lib/asan/asan_descriptions.h
===================================================================
--- lib/asan/asan_descriptions.h
+++ lib/asan/asan_descriptions.h
@@ -165,6 +165,88 @@
 void PrintAddressDescription(uptr addr, uptr access_size = 1,
                              const char *bug_type = "");
 
+enum AddressKind {
+  kAddressKindWild,
+  kAddressKindShadow,
+  kAddressKindHeap,
+  kAddressKindStack,
+  kAddressKindGlobal,
+};
+
+struct NewAddressDescriptionBase {
+  AddressKind kind;
+  union {
+    ShadowAddressDescription shadow;
+    HeapAddressDescription heap;
+    StackAddressDescription stack;
+    GlobalAddressDescription global;
+    uptr addr;
+  };
+  uptr Address() {
+    switch (kind) {
+      case kAddressKindWild:
+        return addr;
+      case kAddressKindShadow:
+        return shadow.addr;
+      case kAddressKindHeap:
+        return heap.addr;
+      case kAddressKindStack:
+        return stack.addr;
+      case kAddressKindGlobal:
+        return global.addr;
+    }
+  }
+  void Print() {
+    switch (kind) {
+      case kAddressKindWild:
+        Printf("Address %p is a wild pointer.\n", addr);
+        return;
+      case kAddressKindShadow:
+        return shadow.Print();
+      case kAddressKindHeap:
+        return heap.Print();
+      case kAddressKindStack:
+        return stack.Print();
+      case kAddressKindGlobal:
+        return global.Print();
+    }
+  }
+};
+
+struct NewAddressDescription : NewAddressDescriptionBase {
+  NewAddressDescription() {
+    kind = kAddressKindWild;
+    addr = 0;
+  }
+  // shouldLockThreadRegistry allows us to skip locking if we're sure we already
+  // have it.
+  NewAddressDescription(uptr addr, bool shouldLockThreadRegistry = true) {
+    if (GetShadowAddressInformation(addr, &shadow)) {
+      kind = kAddressKindShadow;
+      return;
+    }
+    if (GetHeapAddressInformation(addr, 1, &heap)) {
+      kind = kAddressKindHeap;
+      return;
+    }
+
+    if (shouldLockThreadRegistry) asanThreadRegistry().Lock();
+    if (GetStackAddressInformation(addr, &stack)) {
+      kind = kAddressKindStack;
+      if (shouldLockThreadRegistry) asanThreadRegistry().Unlock();
+      return;
+    }
+    if (shouldLockThreadRegistry) asanThreadRegistry().Unlock();
+
+    if (GetGlobalAddressInformation(addr, &global)) {
+      kind = kAddressKindGlobal;
+      return;
+    }
+    kind = kAddressKindWild;
+    addr = 0;
+  }
+};
+
 }  // namespace __asan
 
 #endif  // ASAN_DESCRIPTIONS_H