[compiler-rt] [scudo] Refactor allocator config to support optional flags (PR #81805)

[via llvm-commits]

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@@ -0,0 +1,129 @@
+//===-- allocator_config_wrapper.h ------------------------------*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SCUDO_ALLOCATOR_CONFIG_WRAPPER_H_
+#define SCUDO_ALLOCATOR_CONFIG_WRAPPER_H_
+
+#include "condition_variable.h"
+#include "internal_defs.h"
+#include "secondary.h"
+
+namespace {
+
+template <typename T> struct removeConst {
+  using type = T;
+};
+template <typename T> struct removeConst<const T> {
+  using type = T;
+};
+
+} // namespace
+
+namespace scudo {
+
+#define OPTIONAL_TEMPLATE(TYPE, NAME, DEFAULT, MEMBER)                         \
+  template <typename Config, typename = TYPE> struct NAME##State {             \
+    static constexpr removeConst<TYPE>::type getValue() { return DEFAULT; }    \
+  };                                                                           \
+  template <typename Config>                                                   \
+  struct NAME##State<Config, decltype(Config::MEMBER)> {                       \
+    static constexpr removeConst<TYPE>::type getValue() {                      \
+      return Config::MEMBER;                                                   \
+    }                                                                          \
+  };
+
+#define OPTIONAL_TYPE_TEMPLATE(NAME, DEFAULT, MEMBER)                          \
+  template <typename Config, typename Void = Config> struct NAME##Type {       \
+    static constexpr bool enabled() { return false; }                          \
+    using NAME = DEFAULT;                                                      \
+  };                                                                           \
+  template <typename Config>                                                   \
+  struct NAME##Type<Config, typename Config::MEMBER> {                         \
+    static constexpr bool enabled() { return true; }                           \
+    using NAME = typename Config::MEMBER;                                      \
+  };
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ChiaHungDuan wrote:

I found that this has some problem. Will fix it and add some tests for the macro expansions 

https://github.com/llvm/llvm-project/pull/81805