--- /dev/null
+/* Copyright (C) 2015-2020 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_ENUM_FLAGS_H
+#define COMMON_ENUM_FLAGS_H
+
+/* Type-safe wrapper for enum flags. enum flags are enums where the
+ values are bits that are meant to be ORed together.
+
+ This allows writing code like the below, while with raw enums this
+ would fail to compile without casts to enum type at the assignments
+ to 'f':
+
+ enum some_flag
+ {
+ flag_val1 = 1 << 1,
+ flag_val2 = 1 << 2,
+ flag_val3 = 1 << 3,
+ flag_val4 = 1 << 4,
+ };
+ DEF_ENUM_FLAGS_TYPE(enum some_flag, some_flags);
+
+ some_flags f = flag_val1 | flag_val2;
+ f |= flag_val3;
+
+ It's also possible to assign literal zero to an enum flags variable
+ (meaning, no flags), dispensing adding an awkward explicit "no
+ value" value to the enumeration. For example:
+
+ some_flags f = 0;
+ f |= flag_val3 | flag_val4;
+
+ Note that literal integers other than zero fail to compile:
+
+ some_flags f = 1; // error
+*/
+
+#ifdef __cplusplus
+
+/* Traits type used to prevent the global operator overloads from
+ instantiating for non-flag enums. */
+template<typename T> struct enum_flags_type {};
+
+/* Use this to mark an enum as flags enum. It defines FLAGS as
+ enum_flags wrapper class for ENUM, and enables the global operator
+ overloads for ENUM. */
+#define DEF_ENUM_FLAGS_TYPE(enum_type, flags_type) \
+ typedef enum_flags<enum_type> flags_type; \
+ template<> \
+ struct enum_flags_type<enum_type> \
+ { \
+ typedef enum_flags<enum_type> type; \
+ }
+
+/* Until we can rely on std::underlying type being universally
+ available (C++11), roll our own for enums. */
+template<int size, bool sign> class integer_for_size { typedef void type; };
+template<> struct integer_for_size<1, 0> { typedef uint8_t type; };
+template<> struct integer_for_size<2, 0> { typedef uint16_t type; };
+template<> struct integer_for_size<4, 0> { typedef uint32_t type; };
+template<> struct integer_for_size<8, 0> { typedef uint64_t type; };
+template<> struct integer_for_size<1, 1> { typedef int8_t type; };
+template<> struct integer_for_size<2, 1> { typedef int16_t type; };
+template<> struct integer_for_size<4, 1> { typedef int32_t type; };
+template<> struct integer_for_size<8, 1> { typedef int64_t type; };
+
+template<typename T>
+struct enum_underlying_type
+{
+ typedef typename
+ integer_for_size<sizeof (T), static_cast<bool>(T (-1) < T (0))>::type
+ type;
+};
+
+template <typename E>
+class enum_flags
+{
+public:
+ typedef E enum_type;
+ typedef typename enum_underlying_type<enum_type>::type underlying_type;
+
+private:
+ /* Private type used to support initializing flag types with zero:
+
+ foo_flags f = 0;
+
+ but not other integers:
+
+ foo_flags f = 1;
+
+ The way this works is that we define an implicit constructor that
+ takes a pointer to this private type. Since nothing can
+ instantiate an object of this type, the only possible pointer to
+ pass to the constructor is the NULL pointer, or, zero. */
+ struct zero_type;
+
+ underlying_type
+ underlying_value () const
+ {
+ return m_enum_value;
+ }
+
+public:
+ /* Allow default construction. */
+ enum_flags ()
+ : m_enum_value ((enum_type) 0)
+ {}
+
+ /* If you get an error saying these two overloads are ambiguous,
+ then you tried to mix values of different enum types. */
+ enum_flags (enum_type e)
+ : m_enum_value (e)
+ {}
+ enum_flags (struct enum_flags::zero_type *zero)
+ : m_enum_value ((enum_type) 0)
+ {}
+
+ enum_flags &operator&= (enum_type e)
+ {
+ m_enum_value = (enum_type) (underlying_value () & e);
+ return *this;
+ }
+ enum_flags &operator|= (enum_type e)
+ {
+ m_enum_value = (enum_type) (underlying_value () | e);
+ return *this;
+ }
+ enum_flags &operator^= (enum_type e)
+ {
+ m_enum_value = (enum_type) (underlying_value () ^ e);
+ return *this;
+ }
+
+ operator enum_type () const
+ {
+ return m_enum_value;
+ }
+
+ enum_flags operator& (enum_type e) const
+ {
+ return (enum_type) (underlying_value () & e);
+ }
+ enum_flags operator| (enum_type e) const
+ {
+ return (enum_type) (underlying_value () | e);
+ }
+ enum_flags operator^ (enum_type e) const
+ {
+ return (enum_type) (underlying_value () ^ e);
+ }
+ enum_flags operator~ () const
+ {
+ // We only the underlying type to be unsigned when actually using
+ // operator~ -- if it were not unsigned, undefined behavior could
+ // result. However, asserting this in the class itself would
+ // require too many unnecessary changes to otherwise ok enum
+ // types.
+ gdb_static_assert (std::is_unsigned<underlying_type>::value);
+ return (enum_type) ~underlying_value ();
+ }
+
+private:
+ /* Stored as enum_type because GDB knows to print the bit flags
+ neatly if the enum values look like bit flags. */
+ enum_type m_enum_value;
+};
+
+/* Global operator overloads. */
+
+template <typename enum_type>
+typename enum_flags_type<enum_type>::type
+operator& (enum_type e1, enum_type e2)
+{
+ return enum_flags<enum_type> (e1) & e2;
+}
+
+template <typename enum_type>
+typename enum_flags_type<enum_type>::type
+operator| (enum_type e1, enum_type e2)
+{
+ return enum_flags<enum_type> (e1) | e2;
+}
+
+template <typename enum_type>
+typename enum_flags_type<enum_type>::type
+operator^ (enum_type e1, enum_type e2)
+{
+ return enum_flags<enum_type> (e1) ^ e2;
+}
+
+template <typename enum_type>
+typename enum_flags_type<enum_type>::type
+operator~ (enum_type e)
+{
+ return ~enum_flags<enum_type> (e);
+}
+
+#else /* __cplusplus */
+
+/* In C, the flags type is just a typedef for the enum type. */
+
+#define DEF_ENUM_FLAGS_TYPE(enum_type, flags_type) \
+ typedef enum_type flags_type
+
+#endif /* __cplusplus */
+
+#endif /* COMMON_ENUM_FLAGS_H */
projects / deliverable / binutils-gdb.git / blobdiff