[PATCH] D14341: Asan: utility function to determine first wrongly poisoned byte in container.

[Mike Aizatsky via llvm-commits]

aizatsky updated this revision to Diff 39226.
aizatsky added a comment.

- done


http://reviews.llvm.org/D14341

Files:
  include/sanitizer/common_interface_defs.h
  lib/asan/asan_poisoning.cc
  lib/sanitizer_common/sanitizer_interface_internal.h

Index: lib/sanitizer_common/sanitizer_interface_internal.h
===================================================================
--- lib/sanitizer_common/sanitizer_interface_internal.h
+++ lib/sanitizer_common/sanitizer_interface_internal.h
@@ -53,6 +53,9 @@
   SANITIZER_INTERFACE_ATTRIBUTE
   int __sanitizer_verify_contiguous_container(const void *beg, const void *mid,
                                               const void *end);
+  SANITIZER_INTERFACE_ATTRIBUTE
+  const void* __sanitizer_contiguous_container_find_bad_address(
+      const void *beg, const void *mid, const void *end);
 }  // extern "C"
 
 #endif  // SANITIZER_INTERFACE_INTERNAL_H
Index: lib/asan/asan_poisoning.cc
===================================================================
--- lib/asan/asan_poisoning.cc
+++ lib/asan/asan_poisoning.cc
@@ -375,10 +375,9 @@
   }
 }
 
-int __sanitizer_verify_contiguous_container(const void *beg_p,
-                                            const void *mid_p,
-                                            const void *end_p) {
-  if (!flags()->detect_container_overflow) return 1;
+const void* __sanitizer_contiguous_container_find_bad_address(
+    const void *beg_p, const void *mid_p, const void *end_p) {
+  if (!flags()->detect_container_overflow) return nullptr;
   uptr beg = reinterpret_cast<uptr>(beg_p);
   uptr end = reinterpret_cast<uptr>(end_p);
   uptr mid = reinterpret_cast<uptr>(mid_p);
@@ -395,17 +394,24 @@
   uptr r3_end = end;
   for (uptr i = r1_beg; i < r1_end; i++)
     if (AddressIsPoisoned(i))
-      return 0;
+      return reinterpret_cast<const void*>(i);
   for (uptr i = r2_beg; i < mid; i++)
     if (AddressIsPoisoned(i))
-      return 0;
+      return reinterpret_cast<const void*>(i);
   for (uptr i = mid; i < r2_end; i++)
     if (!AddressIsPoisoned(i))
-      return 0;
+      return reinterpret_cast<const void*>(i);
   for (uptr i = r3_beg; i < r3_end; i++)
     if (!AddressIsPoisoned(i))
-      return 0;
-  return 1;
+      return reinterpret_cast<const void*>(i);
+  return nullptr;
+}
+
+int __sanitizer_verify_contiguous_container(const void *beg_p,
+                                            const void *mid_p,
+                                            const void *end_p) {
+  return __sanitizer_contiguous_container_find_bad_address(beg_p, mid_p, end_p)
+      == nullptr;
 }
 
 extern "C" SANITIZER_INTERFACE_ATTRIBUTE
Index: include/sanitizer/common_interface_defs.h
===================================================================
--- include/sanitizer/common_interface_defs.h
+++ include/sanitizer/common_interface_defs.h
@@ -105,7 +105,14 @@
   int __sanitizer_verify_contiguous_container(const void *beg, const void *mid,
                                               const void *end);
 
-  // Print the stack trace leading to this call. Useful for debugging user code.
+  // Similar to __sanitizer_verify_contiguous_container but  the address of the
+  // first improperly poisoned byte otherwise. Returns null if the area is
+  // poisoned properly.
+  const void* __sanitizer_contiguous_container_find_bad_address(
+      const void *beg, const void *mid, const void *end);
+
+
+// Print the stack trace leading to this call. Useful for debugging user code.
   void __sanitizer_print_stack_trace();
 
   // Sets the callback to be called right before death on error.


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