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binutils-gdb/gdb/common/traits.h

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Update copyright year range in all GDB files gdb/ChangeLog: Update copyright year range in all GDB files
2018-01-01 05:43:02 +01:00
/* Copyright (C) 2017-2018 Free Software Foundation, Inc.
Make sect_offset and cu_offset strong typedefs instead of structs A while ago, back when GDB was a C program, the sect_offset and cu_offset types were made structs in order to prevent incorrect mixing of those offsets. Now that we require C++11, we can make them integers again, while keeping the safety, by exploiting "enum class". We can add a bit more safety, even, by defining operators that the types _should_ support, helping making the suspicious uses stand out more. Getting at the underlying type is done with the new to_underlying function added by the previous patch, which also helps better spot where do we need to step out of the safety net. Mostly, that's around parsing the DWARF, and when we print the offset for complaint/debug purposes. But there are other occasional uses. Since we have to define the sect_offset/cu_offset types in a header anyway, I went ahead and generalized/library-fied the idea of "offset" types, making it trivial to add more such types if we find a use. See common/offset-type.h and the DEFINE_OFFSET_TYPE macro. I needed a couple generaly-useful preprocessor bits (e.g., yet another CONCAT implementation), so I started a new common/preprocessor.h file. I included units tests covering the "offset" types API. These are mostly compile-time tests, using SFINAE to check that expressions that shouldn't compile (e.g., comparing unrelated offset types) really are invalid and would fail to compile. This same idea appeared in my pending enum-flags revamp from a few months ago (though this version is a bit further modernized compared to what I had posted), and I plan on reusing the "check valid expression" bits added here in that series, so I went ahead and defined the CHECK_VALID_EXPR macro in its own header -- common/valid-expr.h. I think that's nicer regardless. I was borderline between calling the new types "offset" types, or "index" types, BTW. I stuck with "offset" simply because that's what we're already calling them, mostly. gdb/ChangeLog: 2017-04-04 Pedro Alves <palves@redhat.com> * Makefile.in (SUBDIR_UNITTESTS_SRCS): Add unittests/offset-type-selftests.c. (SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o. * common/offset-type.h: New file. * common/preprocessor.h: New file. * common/traits.h: New file. * common/valid-expr.h: New file. * dwarf2expr.c: Include "common/underlying.h". Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2expr.h: Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2loc.c: Include "common/underlying.h". Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2read.c: Adjust to use sect_offset and cu_offset strong typedefs throughout. * gdbtypes.h: Include "common/offset-type.h". (cu_offset): Now an offset type (strong typedef) instead of a struct. (sect_offset): Likewise. (union call_site_parameter_u): Rename "param_offset" field to "param_cu_off". * unittests/offset-type-selftests.c: New file.
2017-04-04 21:03:26 +02:00
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_TRAITS_H
#define COMMON_TRAITS_H
More gdb::optional features Currently we can't use gdb::optional<T> as function return type, because gdb::optional's copy ctor is deleted. For example, with: gdb::optional<int> function () { gdb::optional<int> opt; .... return opt; we get: src/gdb/foo.c: In function ‘gdb::optional<int> foo()’: src/gdb/foo.c:75:10: error: use of deleted function ‘gdb::optional<T>::optional(const gdb::optional<T>&) [with T = int]’ return opt; ^ In file included from src/gdb/foo.c:68:0: src/gdb/common/gdb_optional.h:53:3: note: declared here optional (const optional &other) = delete; ^ I started by fixing that, and then ran into another missing feature, also fixed by this patch. The next feature I'm missing most from gdb::optional<T> compared to std::optional<T> is construction/move/assignment from a T, instead of having to default construct an gdb::optional and then use optional::emplace(....). For example: gdb::optional<std::string> function () { gdb::optional<std::string> opt; std::string str; ... opt.emplace (std::move (str)); return opt; vs gdb::optional<std::string> function () { std::string str; ... return str; The copy/move ctor/assign methods weren't initialy implemented because std::optional supports construction from a type U if U is convertible to T too, and has rules to decide whether the ctors are explicit/implicit based on that, and rules for whether the ctor should be trivial or not, etc., which leads to a much more complicated implementation. If we stick to supporting copy/move construction/assignment of/to an optional<T> from exactly only optional<T> and T, then all that conversion-related complication disappears, and we still gain convenience in most use cases. The patch also makes emplace return a reference to the constructor object, per C++17 std::optional, and adds a reset method, againt because std::optional has one and it's trivial to support it. These two changes are a requirement of the gdb::optional unit testing patch that will follow. gdb/ChangeLog: 2017-04-18 Pedro Alves <palves@redhat.com> * common/gdb_optional.h: Include common/traits.h. (in_place_t): New type. (in_place): New constexpr variable. (optional::optional): Remove member initialization of m_instantiated. (optional::optional(in_place_t...)): New constructor. (optional::~optional): Use reset. (optional::optional(const optional&)): New. (optional::optional(const optional&&)): New. (optional::optional(T &)): New. (optional::optional(T &&)): New. (operator::operator=(const optional &)): New. (operator::operator=(optional &&)): New. (operator::operator= (const T &)) (operator::operator= (T &&)) (operator::emplace (Args &&... args)): Return a T&. Use reset. (operator::reset): New. (operator::m_instantiated):: Add in-class initializer. * common/traits.h: Include <type_traits>. (struct And): New types.
2017-04-18 22:39:24 +02:00
#include <type_traits>
Fix build on gcc < 5 (std::is_trivially_copyable missing) Ref: https://sourceware.org/ml/gdb-patches/2017-04/msg00660.html Simply skip the poisoning on older compilers. gdb/ChangeLog: 2017-04-25 Pedro Alves <palves@redhat.com> * common/poison.h [!HAVE_IS_TRIVIALLY_COPYABLE] (IsRelocatable) (BothAreRelocatable, memcopy, memmove): Don't define. * common/traits.h (__has_feature, HAVE_IS_TRIVIALLY_COPYABLE): New macros.
2017-04-25 11:58:57 +02:00
/* GCC does not understand __has_feature. */
#if !defined(__has_feature)
# define __has_feature(x) 0
#endif
/* HAVE_IS_TRIVIALLY_COPYABLE is defined as 1 iff
std::is_trivially_copyable is available. GCC only implemented it
in GCC 5. */
#if (__has_feature(is_trivially_copyable) \
|| (defined __GNUC__ && __GNUC__ >= 5))
# define HAVE_IS_TRIVIALLY_COPYABLE 1
#endif
Make sect_offset and cu_offset strong typedefs instead of structs A while ago, back when GDB was a C program, the sect_offset and cu_offset types were made structs in order to prevent incorrect mixing of those offsets. Now that we require C++11, we can make them integers again, while keeping the safety, by exploiting "enum class". We can add a bit more safety, even, by defining operators that the types _should_ support, helping making the suspicious uses stand out more. Getting at the underlying type is done with the new to_underlying function added by the previous patch, which also helps better spot where do we need to step out of the safety net. Mostly, that's around parsing the DWARF, and when we print the offset for complaint/debug purposes. But there are other occasional uses. Since we have to define the sect_offset/cu_offset types in a header anyway, I went ahead and generalized/library-fied the idea of "offset" types, making it trivial to add more such types if we find a use. See common/offset-type.h and the DEFINE_OFFSET_TYPE macro. I needed a couple generaly-useful preprocessor bits (e.g., yet another CONCAT implementation), so I started a new common/preprocessor.h file. I included units tests covering the "offset" types API. These are mostly compile-time tests, using SFINAE to check that expressions that shouldn't compile (e.g., comparing unrelated offset types) really are invalid and would fail to compile. This same idea appeared in my pending enum-flags revamp from a few months ago (though this version is a bit further modernized compared to what I had posted), and I plan on reusing the "check valid expression" bits added here in that series, so I went ahead and defined the CHECK_VALID_EXPR macro in its own header -- common/valid-expr.h. I think that's nicer regardless. I was borderline between calling the new types "offset" types, or "index" types, BTW. I stuck with "offset" simply because that's what we're already calling them, mostly. gdb/ChangeLog: 2017-04-04 Pedro Alves <palves@redhat.com> * Makefile.in (SUBDIR_UNITTESTS_SRCS): Add unittests/offset-type-selftests.c. (SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o. * common/offset-type.h: New file. * common/preprocessor.h: New file. * common/traits.h: New file. * common/valid-expr.h: New file. * dwarf2expr.c: Include "common/underlying.h". Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2expr.h: Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2loc.c: Include "common/underlying.h". Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2read.c: Adjust to use sect_offset and cu_offset strong typedefs throughout. * gdbtypes.h: Include "common/offset-type.h". (cu_offset): Now an offset type (strong typedef) instead of a struct. (sect_offset): Likewise. (union call_site_parameter_u): Rename "param_offset" field to "param_cu_off". * unittests/offset-type-selftests.c: New file.
2017-04-04 21:03:26 +02:00
namespace gdb {
/* Pre C++14-safe (CWG 1558) version of C++17's std::void_t. See
<http://en.cppreference.com/w/cpp/types/void_t>. */
template<typename... Ts>
struct make_void { typedef void type; };
template<typename... Ts>
using void_t = typename make_void<Ts...>::type;
More gdb::optional features Currently we can't use gdb::optional<T> as function return type, because gdb::optional's copy ctor is deleted. For example, with: gdb::optional<int> function () { gdb::optional<int> opt; .... return opt; we get: src/gdb/foo.c: In function ‘gdb::optional<int> foo()’: src/gdb/foo.c:75:10: error: use of deleted function ‘gdb::optional<T>::optional(const gdb::optional<T>&) [with T = int]’ return opt; ^ In file included from src/gdb/foo.c:68:0: src/gdb/common/gdb_optional.h:53:3: note: declared here optional (const optional &other) = delete; ^ I started by fixing that, and then ran into another missing feature, also fixed by this patch. The next feature I'm missing most from gdb::optional<T> compared to std::optional<T> is construction/move/assignment from a T, instead of having to default construct an gdb::optional and then use optional::emplace(....). For example: gdb::optional<std::string> function () { gdb::optional<std::string> opt; std::string str; ... opt.emplace (std::move (str)); return opt; vs gdb::optional<std::string> function () { std::string str; ... return str; The copy/move ctor/assign methods weren't initialy implemented because std::optional supports construction from a type U if U is convertible to T too, and has rules to decide whether the ctors are explicit/implicit based on that, and rules for whether the ctor should be trivial or not, etc., which leads to a much more complicated implementation. If we stick to supporting copy/move construction/assignment of/to an optional<T> from exactly only optional<T> and T, then all that conversion-related complication disappears, and we still gain convenience in most use cases. The patch also makes emplace return a reference to the constructor object, per C++17 std::optional, and adds a reset method, againt because std::optional has one and it's trivial to support it. These two changes are a requirement of the gdb::optional unit testing patch that will follow. gdb/ChangeLog: 2017-04-18 Pedro Alves <palves@redhat.com> * common/gdb_optional.h: Include common/traits.h. (in_place_t): New type. (in_place): New constexpr variable. (optional::optional): Remove member initialization of m_instantiated. (optional::optional(in_place_t...)): New constructor. (optional::~optional): Use reset. (optional::optional(const optional&)): New. (optional::optional(const optional&&)): New. (optional::optional(T &)): New. (optional::optional(T &&)): New. (operator::operator=(const optional &)): New. (operator::operator=(optional &&)): New. (operator::operator= (const T &)) (operator::operator= (T &&)) (operator::emplace (Args &&... args)): Return a T&. Use reset. (operator::reset): New. (operator::m_instantiated):: Add in-class initializer. * common/traits.h: Include <type_traits>. (struct And): New types.
2017-04-18 22:39:24 +02:00
/* A few trait helpers, mainly stolen from libstdc++. Uppercase
Poison non-POD memset & non-trivially-copyable memcpy/memmove This patch catches invalid initialization of non-POD types with memset, at compile time. This is what I used to catch the problems fixed by the previous patches in the series: $ make -k 2>&1 | grep "deleted function" src/gdb/breakpoint.c:951:53: error: use of deleted function ‘void* memset(T*, int, size_t) [with T = bp_location; <template-parameter-1-2> = void; size_t = long unsigned int]’ src/gdb/breakpoint.c:7325:32: error: use of deleted function ‘void* memset(T*, int, size_t) [with T = bp_location; <template-parameter-1-2> = void; size_t = long unsigned int]’ src/gdb/btrace.c:1153:42: error: use of deleted function ‘void* memset(T*, int, size_t) [with T = btrace_insn; <template-parameter-1-2> = void; size_t = long unsigned int]’ ... gdb/ChangeLog: 2017-04-25 Pedro Alves <palves@redhat.com> * common/common-defs.h: Include "common/poison.h". * common/function-view.h: (Not, Or, Requires): Move to traits.h and adjust. * common/poison.h: New file. * common/traits.h: Include <type_traits>. (Not, Or, Requires): New, moved from common/function-view.h.
2017-04-25 02:27:41 +02:00
because "and/or", etc. are reserved keywords. */
template<typename Predicate>
struct Not : public std::integral_constant<bool, !Predicate::value>
{};
template<typename...>
struct Or;
template<>
struct Or<> : public std::false_type
{};
template<typename B1>
struct Or<B1> : public B1
{};
template<typename B1, typename B2>
struct Or<B1, B2>
: public std::conditional<B1::value, B1, B2>::type
{};
template<typename B1,typename B2,typename B3, typename... Bn>
struct Or<B1, B2, B3, Bn...>
: public std::conditional<B1::value, B1, Or<B2, B3, Bn...>>::type
{};
More gdb::optional features Currently we can't use gdb::optional<T> as function return type, because gdb::optional's copy ctor is deleted. For example, with: gdb::optional<int> function () { gdb::optional<int> opt; .... return opt; we get: src/gdb/foo.c: In function ‘gdb::optional<int> foo()’: src/gdb/foo.c:75:10: error: use of deleted function ‘gdb::optional<T>::optional(const gdb::optional<T>&) [with T = int]’ return opt; ^ In file included from src/gdb/foo.c:68:0: src/gdb/common/gdb_optional.h:53:3: note: declared here optional (const optional &other) = delete; ^ I started by fixing that, and then ran into another missing feature, also fixed by this patch. The next feature I'm missing most from gdb::optional<T> compared to std::optional<T> is construction/move/assignment from a T, instead of having to default construct an gdb::optional and then use optional::emplace(....). For example: gdb::optional<std::string> function () { gdb::optional<std::string> opt; std::string str; ... opt.emplace (std::move (str)); return opt; vs gdb::optional<std::string> function () { std::string str; ... return str; The copy/move ctor/assign methods weren't initialy implemented because std::optional supports construction from a type U if U is convertible to T too, and has rules to decide whether the ctors are explicit/implicit based on that, and rules for whether the ctor should be trivial or not, etc., which leads to a much more complicated implementation. If we stick to supporting copy/move construction/assignment of/to an optional<T> from exactly only optional<T> and T, then all that conversion-related complication disappears, and we still gain convenience in most use cases. The patch also makes emplace return a reference to the constructor object, per C++17 std::optional, and adds a reset method, againt because std::optional has one and it's trivial to support it. These two changes are a requirement of the gdb::optional unit testing patch that will follow. gdb/ChangeLog: 2017-04-18 Pedro Alves <palves@redhat.com> * common/gdb_optional.h: Include common/traits.h. (in_place_t): New type. (in_place): New constexpr variable. (optional::optional): Remove member initialization of m_instantiated. (optional::optional(in_place_t...)): New constructor. (optional::~optional): Use reset. (optional::optional(const optional&)): New. (optional::optional(const optional&&)): New. (optional::optional(T &)): New. (optional::optional(T &&)): New. (operator::operator=(const optional &)): New. (operator::operator=(optional &&)): New. (operator::operator= (const T &)) (operator::operator= (T &&)) (operator::emplace (Args &&... args)): Return a T&. Use reset. (operator::reset): New. (operator::m_instantiated):: Add in-class initializer. * common/traits.h: Include <type_traits>. (struct And): New types.
2017-04-18 22:39:24 +02:00
template<typename...>
struct And;
template<>
struct And<> : public std::true_type
{};
template<typename B1>
struct And<B1> : public B1
{};
template<typename B1, typename B2>
struct And<B1, B2>
: public std::conditional<B1::value, B2, B1>::type
{};
template<typename B1, typename B2, typename B3, typename... Bn>
struct And<B1, B2, B3, Bn...>
: public std::conditional<B1::value, And<B2, B3, Bn...>, B1>::type
{};
Poison non-POD memset & non-trivially-copyable memcpy/memmove This patch catches invalid initialization of non-POD types with memset, at compile time. This is what I used to catch the problems fixed by the previous patches in the series: $ make -k 2>&1 | grep "deleted function" src/gdb/breakpoint.c:951:53: error: use of deleted function ‘void* memset(T*, int, size_t) [with T = bp_location; <template-parameter-1-2> = void; size_t = long unsigned int]’ src/gdb/breakpoint.c:7325:32: error: use of deleted function ‘void* memset(T*, int, size_t) [with T = bp_location; <template-parameter-1-2> = void; size_t = long unsigned int]’ src/gdb/btrace.c:1153:42: error: use of deleted function ‘void* memset(T*, int, size_t) [with T = btrace_insn; <template-parameter-1-2> = void; size_t = long unsigned int]’ ... gdb/ChangeLog: 2017-04-25 Pedro Alves <palves@redhat.com> * common/common-defs.h: Include "common/poison.h". * common/function-view.h: (Not, Or, Requires): Move to traits.h and adjust. * common/poison.h: New file. * common/traits.h: Include <type_traits>. (Not, Or, Requires): New, moved from common/function-view.h.
2017-04-25 02:27:41 +02:00
/* Concepts-light-like helper to make SFINAE logic easier to read. */
template<typename Condition>
using Requires = typename std::enable_if<Condition::value, void>::type;
Make sect_offset and cu_offset strong typedefs instead of structs A while ago, back when GDB was a C program, the sect_offset and cu_offset types were made structs in order to prevent incorrect mixing of those offsets. Now that we require C++11, we can make them integers again, while keeping the safety, by exploiting "enum class". We can add a bit more safety, even, by defining operators that the types _should_ support, helping making the suspicious uses stand out more. Getting at the underlying type is done with the new to_underlying function added by the previous patch, which also helps better spot where do we need to step out of the safety net. Mostly, that's around parsing the DWARF, and when we print the offset for complaint/debug purposes. But there are other occasional uses. Since we have to define the sect_offset/cu_offset types in a header anyway, I went ahead and generalized/library-fied the idea of "offset" types, making it trivial to add more such types if we find a use. See common/offset-type.h and the DEFINE_OFFSET_TYPE macro. I needed a couple generaly-useful preprocessor bits (e.g., yet another CONCAT implementation), so I started a new common/preprocessor.h file. I included units tests covering the "offset" types API. These are mostly compile-time tests, using SFINAE to check that expressions that shouldn't compile (e.g., comparing unrelated offset types) really are invalid and would fail to compile. This same idea appeared in my pending enum-flags revamp from a few months ago (though this version is a bit further modernized compared to what I had posted), and I plan on reusing the "check valid expression" bits added here in that series, so I went ahead and defined the CHECK_VALID_EXPR macro in its own header -- common/valid-expr.h. I think that's nicer regardless. I was borderline between calling the new types "offset" types, or "index" types, BTW. I stuck with "offset" simply because that's what we're already calling them, mostly. gdb/ChangeLog: 2017-04-04 Pedro Alves <palves@redhat.com> * Makefile.in (SUBDIR_UNITTESTS_SRCS): Add unittests/offset-type-selftests.c. (SUBDIR_UNITTESTS_OBS): Add offset-type-selftests.o. * common/offset-type.h: New file. * common/preprocessor.h: New file. * common/traits.h: New file. * common/valid-expr.h: New file. * dwarf2expr.c: Include "common/underlying.h". Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2expr.h: Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2loc.c: Include "common/underlying.h". Adjust to use sect_offset and cu_offset strong typedefs throughout. * dwarf2read.c: Adjust to use sect_offset and cu_offset strong typedefs throughout. * gdbtypes.h: Include "common/offset-type.h". (cu_offset): Now an offset type (strong typedef) instead of a struct. (sect_offset): Likewise. (union call_site_parameter_u): Rename "param_offset" field to "param_cu_off". * unittests/offset-type-selftests.c: New file.
2017-04-04 21:03:26 +02:00
}
#endif /* COMMON_TRAITS_H */