Modify allocator_shim to support _aligned_alloc(), _aligned_free().

base/allocator/allocator_unittests.cc

Index: base/allocator/allocator_unittests.cc
diff --git a/base/allocator/allocator_unittests.cc b/base/allocator/allocator_unittests.cc
index a40afdf99f0e22f2be85ffa51bc58fcd866b65b6..30bc411b02d3317bff706a3baa724e8559994afa 100644
--- a/base/allocator/allocator_unittests.cc
+++ b/base/allocator/allocator_unittests.cc
@@ -479,6 +479,23 @@ TEST(Allocators, Recalloc) {
     }
   }
 }
+
+// Test windows specific _aligned_malloc() and _aligned_free() methods.
+TEST(Allocators, AlignedMalloc) {
+  // Try allocating data with a bunch of alignments and sizes
+  static const int kTestAlignments[] = {8, 16, 256, 4096};
+  for (int size = 1; size < 1048576; size *= 2) {

[jar (doing other things), 2012/07/30 23:04:22]

By accident, tcmalloc will tend(?) to pass this test, as new (never before seen)
sizes are usually allocated out of a thread-local heap of a given "size class." 
Each time we try a new size, we will usually get the first element of a span,
which is a 4K aligned allocation).

It would probably be nicer if you would try for some larger alignment factors
(over 4K), and it would also be nicer if you asked for two aligned allocation of
each size (so that we'd be assured we weren't just getting the first item from a
class.

[DaleCurtis, 2012/07/31 00:44:22]

Added 8192, 16384 alignments and allocate two per pass.

+    for (int i = 0; i < ARRAYSIZE(kTestAlignments); ++i) {
+      unsigned char* ptr = reinterpret_cast<unsigned char*>(
+          _aligned_malloc(size, kTestAlignments[i]));

[jar (doing other things), 2012/07/30 23:04:22]

I'd also suggest you allocate "size + 1" to avoid asking for powers of 2, which
*might* have a better shot an nice alignment IMO.

[DaleCurtis, 2012/07/31 00:44:22]

Switched to using NextSize() as many of the other tests here are using.  Tries
power_of_2-1, power_of_2, power_of_2+1.

+      CheckAlignment(ptr, kTestAlignments[i]);
+      Fill(ptr, size);
+      EXPECT_TRUE(Valid(ptr, size));
+      _aligned_free(ptr);
+    }
+  }
+}
+
 #endif