[llvm] r300882 - [Support] Make asan poisoning for recyclers more aggressive by also poisoning the 'next' pointer.

[Benjamin Kramer via llvm-commits]

Author: d0k
Date: Thu Apr 20 15:28:18 2017
New Revision: 300882

URL: http://llvm.org/viewvc/llvm-project?rev=300882&view=rev
Log:
[Support] Make asan poisoning for recyclers more aggressive by also poisoning the 'next' pointer.

Modified:
    llvm/trunk/include/llvm/Support/ArrayRecycler.h
    llvm/trunk/include/llvm/Support/Recycler.h

Modified: llvm/trunk/include/llvm/Support/ArrayRecycler.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/ArrayRecycler.h?rev=300882&r1=300881&r2=300882&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/ArrayRecycler.h (original)
+++ llvm/trunk/include/llvm/Support/ArrayRecycler.h Thu Apr 20 15:28:18 2017
@@ -47,22 +47,21 @@ template <class T, size_t Align = aligno
     FreeList *Entry = Bucket[Idx];
     if (!Entry)
       return nullptr;
+    __asan_unpoison_memory_region(Entry, Capacity::get(Idx).getSize());
     Bucket[Idx] = Entry->Next;
     __msan_allocated_memory(Entry, Capacity::get(Idx).getSize());
-    __asan_unpoison_memory_region(Entry, Capacity::get(Idx).getSize());
     return reinterpret_cast<T*>(Entry);
   }
 
   // Add an entry to the free list at Bucket[Idx].
   void push(unsigned Idx, T *Ptr) {
     assert(Ptr && "Cannot recycle NULL pointer");
-    __asan_poison_memory_region(Ptr, Capacity::get(Idx).getSize());
-    __asan_unpoison_memory_region(Ptr, sizeof(FreeList));
     FreeList *Entry = reinterpret_cast<FreeList*>(Ptr);
     if (Idx >= Bucket.size())
       Bucket.resize(size_t(Idx) + 1);
     Entry->Next = Bucket[Idx];
     Bucket[Idx] = Entry;
+    __asan_poison_memory_region(Ptr, Capacity::get(Idx).getSize());
   }
 
 public:

Modified: llvm/trunk/include/llvm/Support/Recycler.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Recycler.h?rev=300882&r1=300881&r2=300882&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Recycler.h (original)
+++ llvm/trunk/include/llvm/Support/Recycler.h Thu Apr 20 15:28:18 2017
@@ -42,17 +42,16 @@ class Recycler {
 
   FreeNode *pop_val() {
     auto *Val = FreeList;
+    __asan_unpoison_memory_region(Val, Size);
     FreeList = FreeList->Next;
     __msan_allocated_memory(Val, Size);
-    __asan_unpoison_memory_region(Val, Size);
     return Val;
   }
 
   void push(FreeNode *N) {
-    __asan_poison_memory_region(N, Size);
-    __asan_unpoison_memory_region(N, sizeof(FreeNode));
     N->Next = FreeList;
     FreeList = N;
+    __asan_poison_memory_region(N, Size);
   }
 
 public: