From 769af0737297a79486cd48621d0a16856d8e1ccf Mon Sep 17 00:00:00 2001
From: Alexey Samsonov <samsonov@google.com>
Date: Thu, 17 Jan 2013 13:25:17 +0000
Subject: [PATCH] [ASan] fix __asan_get_ownership(p) and
 __asan_get_allocated_size(p) for the p = malloc(0)

llvm-svn: 172717
---
 compiler-rt/lib/asan/asan_allocator2.cc        | 10 ++++++----
 compiler-rt/lib/asan/tests/asan_noinst_test.cc | 10 +++++++++-
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/compiler-rt/lib/asan/asan_allocator2.cc b/compiler-rt/lib/asan/asan_allocator2.cc
index bc953969af6d..42d8b29afd6b 100644
--- a/compiler-rt/lib/asan/asan_allocator2.cc
+++ b/compiler-rt/lib/asan/asan_allocator2.cc
@@ -675,16 +675,18 @@ uptr __asan_get_estimated_allocated_size(uptr size) {
 }
 
 bool __asan_get_ownership(const void *p) {
-  return AllocationSize(reinterpret_cast<uptr>(p)) > 0;
+  uptr ptr = reinterpret_cast<uptr>(p);
+  return (ptr == kReturnOnZeroMalloc) || (AllocationSize(ptr) > 0);
 }
 
 uptr __asan_get_allocated_size(const void *p) {
   if (p == 0) return 0;
-  uptr allocated_size = AllocationSize(reinterpret_cast<uptr>(p));
+  uptr ptr = reinterpret_cast<uptr>(p);
+  uptr allocated_size = AllocationSize(ptr);
   // Die if p is not malloced or if it is already freed.
-  if (allocated_size == 0) {
+  if (allocated_size == 0 && ptr != kReturnOnZeroMalloc) {
     GET_STACK_TRACE_FATAL_HERE;
-    ReportAsanGetAllocatedSizeNotOwned(reinterpret_cast<uptr>(p), &stack);
+    ReportAsanGetAllocatedSizeNotOwned(ptr, &stack);
   }
   return allocated_size;
 }
diff --git a/compiler-rt/lib/asan/tests/asan_noinst_test.cc b/compiler-rt/lib/asan/tests/asan_noinst_test.cc
index fc4a3d1f5f0c..8a7f77455a59 100644
--- a/compiler-rt/lib/asan/tests/asan_noinst_test.cc
+++ b/compiler-rt/lib/asan/tests/asan_noinst_test.cc
@@ -382,8 +382,16 @@ TEST(AddressSanitizerInterface, GetAllocatedSizeAndOwnershipTest) {
   free(array);
   EXPECT_FALSE(__asan_get_ownership(array));
   EXPECT_DEATH(__asan_get_allocated_size(array), kGetAllocatedSizeErrorMsg);
-
   delete int_ptr;
+
+  void *zero_alloc = Ident(malloc(0));
+  if (zero_alloc != 0) {
+    // If malloc(0) is not null, this pointer is owned and should have valid
+    // allocated size.
+    EXPECT_TRUE(__asan_get_ownership(zero_alloc));
+    EXPECT_EQ(0U, __asan_get_allocated_size(zero_alloc));
+  }
+  free(zero_alloc);
 }
 
 TEST(AddressSanitizerInterface, GetCurrentAllocatedBytesTest) {
-- 
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