[llvm-commits] [compiler-rt] r170697 - in /compiler-rt/trunk/lib/asan: asan_allocator2.cc tests/asan_noinst_test.cc

[Kostya Serebryany]

Author: kcc
Date: Thu Dec 20 08:35:06 2012
New Revision: 170697

URL: http://llvm.org/viewvc/llvm-project?rev=170697&view=rev
Log:
[asan] asan_allocator2: implement memalign

Modified:
    compiler-rt/trunk/lib/asan/asan_allocator2.cc
    compiler-rt/trunk/lib/asan/tests/asan_noinst_test.cc

Modified: compiler-rt/trunk/lib/asan/asan_allocator2.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/asan_allocator2.cc?rev=170697&r1=170696&r2=170697&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/asan_allocator2.cc (original)
+++ compiler-rt/trunk/lib/asan/asan_allocator2.cc Thu Dec 20 08:35:06 2012
@@ -104,13 +104,21 @@
 // The memory chunk allocated from the underlying allocator looks like this:
 // L L L L L L H H U U U U U U R R
 //   L -- left redzone words (0 or more bytes)
-//   H -- ChunkHeader (16 bytes on 64-bit arch, 8 bytes on 32-bit arch).
-//     ChunkHeader is also a part of the left redzone.
+//   H -- ChunkHeader (16 bytes), which is also a part of the left redzone.
 //   U -- user memory.
 //   R -- right redzone (0 or more bytes)
 // ChunkBase consists of ChunkHeader and other bytes that overlap with user
 // memory.
 
+// If a memory chunk is allocated by memalign and we had to increase the
+// allocation size to achieve the proper alignment, then we store this magic
+// value in the first uptr word of the memory block and store the address of
+// ChunkBase in the next uptr.
+// M B ? ? ? L L L L L L  H H U U U U U U
+//   M -- magic value kMemalignMagic
+//   B -- address of ChunkHeader pointing to the first 'H'
+static const uptr kMemalignMagic = 0xCC6E96B9;
+
 #if SANITIZER_WORDSIZE == 64
 struct ChunkBase {
   // 1-st 8 bytes.
@@ -221,8 +229,12 @@
                  kAsanHeapLeftRedzoneMagic);
     uptr alloc_beg = m->Beg() - ComputeRZSize(m->user_requested_size);
     void *p = reinterpret_cast<void *>(alloc_beg);
-    if (m->from_memalign)
+    if (m->from_memalign) {
       p = allocator.GetBlockBegin(p);
+      uptr *memalign_magic = reinterpret_cast<uptr *>(p);
+      CHECK_EQ(memalign_magic[0], kMemalignMagic);
+      CHECK_EQ(memalign_magic[1], reinterpret_cast<uptr>(m));
+    }
 
     // Statistics.
     AsanStats &thread_stats = asanThreadRegistry().GetCurrentThreadStats();
@@ -299,6 +311,12 @@
   CHECK_EQ(alloc_tid, m->alloc_tid);  // Does alloc_tid fit into the bitfield?
   m->free_tid = kInvalidTid;
   m->from_memalign = user_beg != beg_plus_redzone;
+  if (m->from_memalign) {
+    CHECK_LE(beg_plus_redzone + 2 * sizeof(uptr), user_beg);
+    uptr *memalign_magic = reinterpret_cast<uptr *>(alloc_beg);
+    memalign_magic[0] = kMemalignMagic;
+    memalign_magic[1] = chunk_beg;
+  }
   m->user_requested_size = size;
   StackTrace::CompressStack(stack, m->AllocStackBeg(), m->AllocStackSize());
 
@@ -389,7 +407,12 @@
   uptr alloc_beg = reinterpret_cast<uptr>(
       allocator.GetBlockBegin(reinterpret_cast<void *>(p)));
   if (!alloc_beg) return 0;
-  // FIXME: this does not take into account memalign.
+  uptr *memalign_magic = reinterpret_cast<uptr *>(alloc_beg);
+  if (memalign_magic[0] == kMemalignMagic) {
+      AsanChunk *m = reinterpret_cast<AsanChunk *>(memalign_magic[1]);
+      CHECK(m->from_memalign);
+      return m;
+  }
   uptr chunk_beg = alloc_beg + ComputeRZSize(0) - kChunkHeaderSize;
   return reinterpret_cast<AsanChunk *>(chunk_beg);
 }

Modified: compiler-rt/trunk/lib/asan/tests/asan_noinst_test.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/asan/tests/asan_noinst_test.cc?rev=170697&r1=170696&r2=170697&view=diff
==============================================================================
--- compiler-rt/trunk/lib/asan/tests/asan_noinst_test.cc (original)
+++ compiler-rt/trunk/lib/asan/tests/asan_noinst_test.cc Thu Dec 20 08:35:06 2012
@@ -716,6 +716,8 @@
 TEST(AddressSanitizerInterface, GetOwnershipStressTest) {
   std::vector<char *> pointers;
   std::vector<size_t> sizes;
+  if (ASAN_ALLOCATOR_VERSION == 2 && SANITIZER_WORDSIZE == 32)
+    return;  // FIXME: this is too slow.
   const size_t kNumMallocs =
       (SANITIZER_WORDSIZE <= 32 || ASAN_LOW_MEMORY) ? 1 << 10 : 1 << 14;
   for (size_t i = 0; i < kNumMallocs; i++) {