1 files changed, 69 insertions, 0 deletions
diff --git a/media/libvpx/libvpx/vpx_ports/compiler_attributes.h b/media/libvpx/libvpx/vpx_ports/compiler_attributes.h
new file mode 100644
index 0000000000..4b468749b8
--- /dev/null
+++ b/media/libvpx/libvpx/vpx_ports/compiler_attributes.h
@@ -0,0 +1,69 @@
+/*
+ *  Copyright (c) 2020 The WebM project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef VPX_VPX_PORTS_COMPILER_ATTRIBUTES_H_
+#define VPX_VPX_PORTS_COMPILER_ATTRIBUTES_H_
+
+#if !defined(__has_feature)
+#define __has_feature(x) 0
+#endif  // !defined(__has_feature)
+
+#if !defined(__has_attribute)
+#define __has_attribute(x) 0
+#endif  // !defined(__has_attribute)
+
+//------------------------------------------------------------------------------
+// Sanitizer attributes.
+
+#if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
+#define VPX_WITH_ASAN 1
+#else
+#define VPX_WITH_ASAN 0
+#endif  // __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
+
+#if defined(__clang__) && __has_attribute(no_sanitize)
+// Both of these have defined behavior and are used in certain operations or
+// optimizations thereof. There are cases where an overflow may be unintended,
+// however, so use of these attributes should be done with care.
+#define VPX_NO_UNSIGNED_OVERFLOW_CHECK \
+  __attribute__((no_sanitize("unsigned-integer-overflow")))
+#if __clang_major__ >= 12
+#define VPX_NO_UNSIGNED_SHIFT_CHECK \
+  __attribute__((no_sanitize("unsigned-shift-base")))
+#endif  // __clang__ >= 12
+#endif  // __clang__
+
+#ifndef VPX_NO_UNSIGNED_OVERFLOW_CHECK
+#define VPX_NO_UNSIGNED_OVERFLOW_CHECK
+#endif
+#ifndef VPX_NO_UNSIGNED_SHIFT_CHECK
+#define VPX_NO_UNSIGNED_SHIFT_CHECK
+#endif
+
+//------------------------------------------------------------------------------
+// Variable attributes.
+
+#if __has_attribute(uninitialized)
+// Attribute "uninitialized" disables -ftrivial-auto-var-init=pattern for
+// the specified variable.
+//
+// -ftrivial-auto-var-init is security risk mitigation feature, so attribute
+// should not be used "just in case", but only to fix real performance
+// bottlenecks when other approaches do not work. In general the compiler is
+// quite effective at eliminating unneeded initializations introduced by the
+// flag, e.g. when they are followed by actual initialization by a program.
+// However if compiler optimization fails and code refactoring is hard, the
+// attribute can be used as a workaround.
+#define VPX_UNINITIALIZED __attribute__((uninitialized))
+#else
+#define VPX_UNINITIALIZED
+#endif  // __has_attribute(uninitialized)
+
+#endif  // VPX_VPX_PORTS_COMPILER_ATTRIBUTES_H_