[binutils-gdb] gdbsupport: assume that compiler supports std::{is_trivially_constructible,is_trivially_copyable}

[binutils-gdb] gdbsupport: assume that compiler supports std::{is_trivially_constructible,is_trivially_copyable}

[Simon Marchi]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=23acbfee6a82cc147b04b74a89d5b34b47c150f4

commit 23acbfee6a82cc147b04b74a89d5b34b47c150f4
Author: Simon Marchi <simon.marchi@efficios.com>
Date:   Wed Feb 21 11:46:52 2024 -0500

    gdbsupport: assume that compiler supports std::{is_trivially_constructible,is_trivially_copyable}
    
    This code was there to support g++ 4, which didn't support
    std::is_trivially_constructible and std::is_trivially_copyable.  Since
    we now require g++ >= 9, I think it's fair to assume that GDB will
    always be compiled with a compiler that supports those.
    
    Change-Id: Ie7c1649139a2f48bf662cac92d7f3e38fb1f1ba1

Diff:
---
 gdb/trad-frame.c                     |  2 --
 gdb/unittests/array-view-selftests.c |  4 ----
 gdb/unittests/enum-flags-selftests.c |  4 ----
 gdb/unittests/packed-selftests.c     |  4 ----
 gdbsupport/check-defines.el          |  2 --
 gdbsupport/packed.h                  |  2 --
 gdbsupport/poison.h                  |  8 --------
 gdbsupport/traits.h                  | 21 ---------------------
 8 files changed, 47 deletions(-)

diff --git a/gdb/trad-frame.c b/gdb/trad-frame.c
index 8b63927b133..c35e08ab280 100644
--- a/gdb/trad-frame.c
+++ b/gdb/trad-frame.c
@@ -61,9 +61,7 @@ trad_frame_reset_saved_regs (struct gdbarch *gdbarch,
 trad_frame_saved_reg *
 trad_frame_alloc_saved_regs (struct gdbarch *gdbarch)
 {
-#ifdef HAVE_IS_TRIVIALLY_CONSTRUCTIBLE
   static_assert (std::is_trivially_constructible<trad_frame_saved_reg>::value);
-#endif
 
   int numregs = gdbarch_num_cooked_regs (gdbarch);
   trad_frame_saved_reg *this_saved_regs
diff --git a/gdb/unittests/array-view-selftests.c b/gdb/unittests/array-view-selftests.c
index 9d2448fefc1..299318ace43 100644
--- a/gdb/unittests/array-view-selftests.c
+++ b/gdb/unittests/array-view-selftests.c
@@ -30,15 +30,11 @@ namespace array_view_tests {
 #define CHECK_TRAIT(TRAIT)			\
   static_assert (std::TRAIT<gdb::array_view<gdb_byte>>::value, "")
 
-#if HAVE_IS_TRIVIALLY_COPYABLE
-
 CHECK_TRAIT (is_trivially_copyable);
 CHECK_TRAIT (is_trivially_move_assignable);
 CHECK_TRAIT (is_trivially_move_constructible);
 CHECK_TRAIT (is_trivially_destructible);
 
-#endif
-
 #undef CHECK_TRAIT
 
 /* Wrapper around std::is_convertible to make the code using it a bit
diff --git a/gdb/unittests/enum-flags-selftests.c b/gdb/unittests/enum-flags-selftests.c
index 607b8ac66a6..54e168173de 100644
--- a/gdb/unittests/enum-flags-selftests.c
+++ b/gdb/unittests/enum-flags-selftests.c
@@ -63,14 +63,10 @@ DEF_ENUM_FLAGS_TYPE (RE, EF);
 DEF_ENUM_FLAGS_TYPE (RE2, EF2);
 DEF_ENUM_FLAGS_TYPE (URE, UEF);
 
-#if HAVE_IS_TRIVIALLY_COPYABLE
-
 /* So that std::vectors of types that have enum_flags fields can
    reallocate efficiently memcpy.  */
 static_assert (std::is_trivially_copyable<EF>::value);
 
-#endif
-
 /* A couple globals used as lvalues in the CHECK_VALID expressions
    below.  Their names (and types) match the uppercase type names
    exposed by CHECK_VALID just to make the expressions easier to
diff --git a/gdb/unittests/packed-selftests.c b/gdb/unittests/packed-selftests.c
index 3f20861ad4a..852a7d364ce 100644
--- a/gdb/unittests/packed-selftests.c
+++ b/gdb/unittests/packed-selftests.c
@@ -46,16 +46,12 @@ static_assert (alignof (packed<test_enum, 4>) == 1);
 #define CHECK_TRAIT(TRAIT)			\
   static_assert (std::TRAIT<packed<test_enum, 1>>::value, "")
 
-#if HAVE_IS_TRIVIALLY_COPYABLE
-
 CHECK_TRAIT (is_trivially_copyable);
 CHECK_TRAIT (is_trivially_copy_constructible);
 CHECK_TRAIT (is_trivially_move_constructible);
 CHECK_TRAIT (is_trivially_copy_assignable);
 CHECK_TRAIT (is_trivially_move_assignable);
 
-#endif
-
 #undef CHECK_TRAIT
 
 /* Entry point.  */
diff --git a/gdbsupport/check-defines.el b/gdbsupport/check-defines.el
index 7603effc29d..b7cf61ba859 100644
--- a/gdbsupport/check-defines.el
+++ b/gdbsupport/check-defines.el
@@ -35,8 +35,6 @@
 (put (intern "HAVE_USEFUL_SBRK") :check-ok t)
 (put (intern "HAVE_SOCKETS") :check-ok t)
 (put (intern "HAVE_F_GETFD") :check-ok t)
-(put (intern "HAVE_IS_TRIVIALLY_COPYABLE") :check-ok t)
-(put (intern "HAVE_IS_TRIVIALLY_CONSTRUCTIBLE") :check-ok t)
 (put (intern "HAVE_DOS_BASED_FILE_SYSTEM") :check-ok t)
 
 (defun check-read-config.in (file)
diff --git a/gdbsupport/packed.h b/gdbsupport/packed.h
index 8035535386b..5c817d4c9cc 100644
--- a/gdbsupport/packed.h
+++ b/gdbsupport/packed.h
@@ -80,9 +80,7 @@ public:
     static_assert (alignof (packed) == 1);
 
     /* Make sure packed can be wrapped with std::atomic.  */
-#if HAVE_IS_TRIVIALLY_COPYABLE
     static_assert (std::is_trivially_copyable<packed>::value);
-#endif
     static_assert (std::is_copy_constructible<packed>::value);
     static_assert (std::is_move_constructible<packed>::value);
     static_assert (std::is_copy_assignable<packed>::value);
diff --git a/gdbsupport/poison.h b/gdbsupport/poison.h
index 0d0159eb7f8..7b4f8e8a178 100644
--- a/gdbsupport/poison.h
+++ b/gdbsupport/poison.h
@@ -56,8 +56,6 @@ 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.  */
 
@@ -83,17 +81,11 @@ 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>>;
diff --git a/gdbsupport/traits.h b/gdbsupport/traits.h
index eb97b965990..92fe59f34af 100644
--- a/gdbsupport/traits.h
+++ b/gdbsupport/traits.h
@@ -20,27 +20,6 @@
 
 #include <type_traits>
 
-/* 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
-
-/* HAVE_IS_TRIVIALLY_CONSTRUCTIBLE is defined as 1 iff
-   std::is_trivially_constructible is available.  GCC only implemented it
-   in GCC 5.  */
-#if (__has_feature(is_trivially_constructible) \
-     || (defined __GNUC__ && __GNUC__ >= 5))
-# define HAVE_IS_TRIVIALLY_CONSTRUCTIBLE 1
-#endif
-
 namespace gdb {
 
 /* Implementation of the detection idiom: