V4: Add headers from LLVM that define an intrusive list template

These intrusive list is used in the follow-up patch, where it is used to
hold a list of basic blocks in a function, and a list of instructions in
the basic block.

The advantage of this implementation is that it there is an easy and
direct access to iterators when you have an element, it defines STL-like
iterators, is double-linked, and you can easily insert before and after
elements. We don't have something like this in Qt, and it's better to
take an existing and well-tested implementation that making a home-grown
one.

Change-Id: Ie8c726eafe6d7558ae6a3550e8ecc2f15f362b17
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 116 insertions, 0 deletions

diff --git a/src/3rdparty/llvm/include/llvm/Support/PointerLikeTypeTraits.h b/src/3rdparty/llvm/include/llvm/Support/PointerLikeTypeTraits.h
new file mode 100644
index 0000000000..794230d606
--- /dev/null
+++ b/src/3rdparty/llvm/include/llvm/Support/PointerLikeTypeTraits.h
@@ -0,0 +1,116 @@
+//===- llvm/Support/PointerLikeTypeTraits.h - Pointer Traits ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the PointerLikeTypeTraits class.  This allows data
+// structures to reason about pointers and other things that are pointer sized.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_POINTERLIKETYPETRAITS_H
+#define LLVM_SUPPORT_POINTERLIKETYPETRAITS_H
+
+#include "llvm/Support/DataTypes.h"
+#include <type_traits>
+
+namespace llvm {
+
+/// A traits type that is used to handle pointer types and things that are just
+/// wrappers for pointers as a uniform entity.
+template <typename T> struct PointerLikeTypeTraits;
+
+namespace detail {
+/// A tiny meta function to compute the log2 of a compile time constant.
+template <size_t N>
+struct ConstantLog2
+    : std::integral_constant<size_t, ConstantLog2<N / 2>::value + 1> {};
+template <> struct ConstantLog2<1> : std::integral_constant<size_t, 0> {};
+
+// Provide a trait to check if T is pointer-like.
+template <typename T, typename U = void> struct HasPointerLikeTypeTraits {
+  static const bool value = false;
+};
+
+// sizeof(T) is valid only for a complete T.
+template <typename T> struct HasPointerLikeTypeTraits<
+  T, decltype((sizeof(PointerLikeTypeTraits<T>) + sizeof(T)), void())> {
+  static const bool value = true;
+};
+
+template <typename T> struct IsPointerLike {
+  static const bool value = HasPointerLikeTypeTraits<T>::value;
+};
+
+template <typename T> struct IsPointerLike<T *> {
+  static const bool value = true;
+};
+} // namespace detail
+
+// Provide PointerLikeTypeTraits for non-cvr pointers.
+template <typename T> struct PointerLikeTypeTraits<T *> {
+  static inline void *getAsVoidPointer(T *P) { return P; }
+  static inline T *getFromVoidPointer(void *P) { return static_cast<T *>(P); }
+
+  enum { NumLowBitsAvailable = detail::ConstantLog2<alignof(T)>::value };
+};
+
+template <> struct PointerLikeTypeTraits<void *> {
+  static inline void *getAsVoidPointer(void *P) { return P; }
+  static inline void *getFromVoidPointer(void *P) { return P; }
+
+  /// Note, we assume here that void* is related to raw malloc'ed memory and
+  /// that malloc returns objects at least 4-byte aligned. However, this may be
+  /// wrong, or pointers may be from something other than malloc. In this case,
+  /// you should specify a real typed pointer or avoid this template.
+  ///
+  /// All clients should use assertions to do a run-time check to ensure that
+  /// this is actually true.
+  enum { NumLowBitsAvailable = 2 };
+};
+
+// Provide PointerLikeTypeTraits for const things.
+template <typename T> struct PointerLikeTypeTraits<const T> {
+  typedef PointerLikeTypeTraits<T> NonConst;
+
+  static inline const void *getAsVoidPointer(const T P) {
+    return NonConst::getAsVoidPointer(P);
+  }
+  static inline const T getFromVoidPointer(const void *P) {
+    return NonConst::getFromVoidPointer(const_cast<void *>(P));
+  }
+  enum { NumLowBitsAvailable = NonConst::NumLowBitsAvailable };
+};
+
+// Provide PointerLikeTypeTraits for const pointers.
+template <typename T> struct PointerLikeTypeTraits<const T *> {
+  typedef PointerLikeTypeTraits<T *> NonConst;
+
+  static inline const void *getAsVoidPointer(const T *P) {
+    return NonConst::getAsVoidPointer(const_cast<T *>(P));
+  }
+  static inline const T *getFromVoidPointer(const void *P) {
+    return NonConst::getFromVoidPointer(const_cast<void *>(P));
+  }
+  enum { NumLowBitsAvailable = NonConst::NumLowBitsAvailable };
+};
+
+// Provide PointerLikeTypeTraits for uintptr_t.
+template <> struct PointerLikeTypeTraits<uintptr_t> {
+  static inline void *getAsVoidPointer(uintptr_t P) {
+    return reinterpret_cast<void *>(P);
+  }
+  static inline uintptr_t getFromVoidPointer(void *P) {
+    return reinterpret_cast<uintptr_t>(P);
+  }
+  // No bits are available!
+  enum { NumLowBitsAvailable = 0 };
+};
+
+} // end namespace llvm
+
+#endif