1 files changed, 63 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/gwp_asan/utilities.cpp b/contrib/llvm-project/compiler-rt/lib/gwp_asan/utilities.cpp
new file mode 100644
index 000000000000..287630f89531
--- /dev/null
+++ b/contrib/llvm-project/compiler-rt/lib/gwp_asan/utilities.cpp
@@ -0,0 +1,63 @@
+//===-- utilities.cpp -------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "gwp_asan/utilities.h"
+
+#include <assert.h>
+
+namespace gwp_asan {
+// See `bionic/tests/malloc_test.cpp` in the Android source for documentation
+// regarding their alignment guarantees. We always round up to the closest
+// 8-byte window. As GWP-ASan's malloc(X) can always get exactly an X-sized
+// allocation, an allocation that rounds up to 16-bytes will always be given a
+// 16-byte aligned allocation.
+static size_t alignBionic(size_t RealAllocationSize) {
+  if (RealAllocationSize % 8 == 0)
+    return RealAllocationSize;
+  return RealAllocationSize + 8 - (RealAllocationSize % 8);
+}
+
+static size_t alignPowerOfTwo(size_t RealAllocationSize) {
+  if (RealAllocationSize <= 2)
+    return RealAllocationSize;
+  if (RealAllocationSize <= 4)
+    return 4;
+  if (RealAllocationSize <= 8)
+    return 8;
+  if (RealAllocationSize % 16 == 0)
+    return RealAllocationSize;
+  return RealAllocationSize + 16 - (RealAllocationSize % 16);
+}
+
+#ifdef __BIONIC__
+static constexpr AlignmentStrategy PlatformDefaultAlignment =
+    AlignmentStrategy::BIONIC;
+#else  // __BIONIC__
+static constexpr AlignmentStrategy PlatformDefaultAlignment =
+    AlignmentStrategy::POWER_OF_TWO;
+#endif // __BIONIC__
+
+size_t rightAlignedAllocationSize(size_t RealAllocationSize,
+                                  AlignmentStrategy Align) {
+  assert(RealAllocationSize > 0);
+  if (Align == AlignmentStrategy::DEFAULT)
+    Align = PlatformDefaultAlignment;
+
+  switch (Align) {
+  case AlignmentStrategy::BIONIC:
+    return alignBionic(RealAllocationSize);
+  case AlignmentStrategy::POWER_OF_TWO:
+    return alignPowerOfTwo(RealAllocationSize);
+  case AlignmentStrategy::PERFECT:
+    return RealAllocationSize;
+  case AlignmentStrategy::DEFAULT:
+    __builtin_unreachable();
+  }
+  __builtin_unreachable();
+}
+} // namespace gwp_asan