1 files changed, 248 insertions, 0 deletions
diff --git a/gdbsupport/poison.h b/gdbsupport/poison.h
new file mode 100644
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+/* Poison symbols at compile time.
+
+   Copyright (C) 2017-2020 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef COMMON_POISON_H
+#define COMMON_POISON_H
+
+#include "traits.h"
+#include "obstack.h"
+
+/* Poison memset of non-POD types.  The idea is catching invalid
+   initialization of non-POD structs that is easy to be introduced as
+   side effect of refactoring.  For example, say this:
+
+ struct S { VEC(foo_s) *m_data; };
+
+is converted to this at some point:
+
+ struct S {
+   S() { m_data.reserve (10); }
+   std::vector<foo> m_data;
+ };
+
+and old code was initializing S objects like this:
+
+ struct S s;
+ memset (&s, 0, sizeof (S)); // whoops, now wipes vector.
+
+Declaring memset as deleted for non-POD types makes the memset above
+be a compile-time error.  */
+
+/* Helper for SFINAE.  True if "T *" is memsettable.  I.e., if T is
+   either void, or POD.  */
+template<typename T>
+struct IsMemsettable
+  : gdb::Or<std::is_void<T>,
+	    std::is_pod<T>>
+{};
+
+template <typename T,
+	  typename = gdb::Requires<gdb::Not<IsMemsettable<T>>>>
+void *memset (T *s, int c, size_t n) = delete;
+
+#if HAVE_IS_TRIVIALLY_COPYABLE
+
+/* Similarly, poison memcpy and memmove of non trivially-copyable
+   types, which is undefined.  */
+
+/* True if "T *" is relocatable.  I.e., copyable with memcpy/memmove.
+   I.e., T is either trivially copyable, or void.  */
+template<typename T>
+struct IsRelocatable
+  : gdb::Or<std::is_void<T>,
+	    std::is_trivially_copyable<T>>
+{};
+
+/* True if both source and destination are relocatable.  */
+
+template <typename D, typename S>
+using BothAreRelocatable
+  = gdb::And<IsRelocatable<D>, IsRelocatable<S>>;
+
+template <typename D, typename S,
+	  typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>>
+void *memcpy (D *dest, const S *src, size_t n) = delete;
+
+template <typename D, typename S,
+	  typename = gdb::Requires<gdb::Not<BothAreRelocatable<D, S>>>>
+void *memmove (D *dest, const S *src, size_t n) = delete;
+
+#endif /* HAVE_IS_TRIVIALLY_COPYABLE */
+
+/* Poison XNEW and friends to catch usages of malloc-style allocations on
+   objects that require new/delete.  */
+
+template<typename T>
+#if HAVE_IS_TRIVIALLY_CONSTRUCTIBLE
+using IsMallocable = std::is_trivially_constructible<T>;
+#else
+using IsMallocable = std::true_type;
+#endif
+
+template<typename T>
+using IsFreeable = gdb::Or<std::is_trivially_destructible<T>, std::is_void<T>>;
+
+template <typename T, typename = gdb::Requires<gdb::Not<IsFreeable<T>>>>
+void free (T *ptr) = delete;
+
+template<typename T>
+static T *
+xnew ()
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XNEW with a non-POD \
+data type.  Use operator new instead.");
+  return XNEW (T);
+}
+
+#undef XNEW
+#define XNEW(T) xnew<T>()
+
+template<typename T>
+static T *
+xcnew ()
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XCNEW with a non-POD \
+data type.  Use operator new instead.");
+  return XCNEW (T);
+}
+
+#undef XCNEW
+#define XCNEW(T) xcnew<T>()
+
+template<typename T>
+static void
+xdelete (T *p)
+{
+  static_assert (IsFreeable<T>::value, "Trying to use XDELETE with a non-POD \
+data type.  Use operator delete instead.");
+  XDELETE (p);
+}
+
+#undef XDELETE
+#define XDELETE(P) xdelete (P)
+
+template<typename T>
+static T *
+xnewvec (size_t n)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XNEWVEC with a \
+non-POD data type.  Use operator new[] (or std::vector) instead.");
+  return XNEWVEC (T, n);
+}
+
+#undef XNEWVEC
+#define XNEWVEC(T, N) xnewvec<T> (N)
+
+template<typename T>
+static T *
+xcnewvec (size_t n)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XCNEWVEC with a \
+non-POD data type.  Use operator new[] (or std::vector) instead.");
+  return XCNEWVEC (T, n);
+}
+
+#undef XCNEWVEC
+#define XCNEWVEC(T, N) xcnewvec<T> (N)
+
+template<typename T>
+static T *
+xresizevec (T *p, size_t n)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XRESIZEVEC with a \
+non-POD data type.");
+  return XRESIZEVEC (T, p, n);
+}
+
+#undef XRESIZEVEC
+#define XRESIZEVEC(T, P, N) xresizevec<T> (P, N)
+
+template<typename T>
+static void
+xdeletevec (T *p)
+{
+  static_assert (IsFreeable<T>::value, "Trying to use XDELETEVEC with a \
+non-POD data type.  Use operator delete[] (or std::vector) instead.");
+  XDELETEVEC (p);
+}
+
+#undef XDELETEVEC
+#define XDELETEVEC(P) xdeletevec (P)
+
+template<typename T>
+static T *
+xnewvar (size_t s)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XNEWVAR with a \
+non-POD data type.");
+  return XNEWVAR (T, s);;
+}
+
+#undef XNEWVAR
+#define XNEWVAR(T, S) xnewvar<T> (S)
+
+template<typename T>
+static T *
+xcnewvar (size_t s)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XCNEWVAR with a \
+non-POD data type.");
+  return XCNEWVAR (T, s);
+}
+
+#undef XCNEWVAR
+#define XCNEWVAR(T, S) xcnewvar<T> (S)
+
+template<typename T>
+static T *
+xresizevar (T *p, size_t s)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XRESIZEVAR with a \
+non-POD data type.");
+  return XRESIZEVAR (T, p, s);
+}
+
+#undef XRESIZEVAR
+#define XRESIZEVAR(T, P, S) xresizevar<T> (P, S)
+
+template<typename T>
+static T *
+xobnew (obstack *ob)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XOBNEW with a \
+non-POD data type.");
+  return XOBNEW (ob, T);
+}
+
+#undef XOBNEW
+#define XOBNEW(O, T) xobnew<T> (O)
+
+template<typename T>
+static T *
+xobnewvec (obstack *ob, size_t n)
+{
+  static_assert (IsMallocable<T>::value, "Trying to use XOBNEWVEC with a \
+non-POD data type.");
+  return XOBNEWVEC (ob, T, n);
+}
+
+#undef XOBNEWVEC
+#define XOBNEWVEC(O, T, N) xobnewvec<T> (O, N)
+
+#endif /* COMMON_POISON_H */