From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1005) id F05453959E71; Tue, 1 Sep 2020 20:33:36 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org F05453959E71 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1598992416; bh=BWLnGMNeiN1SIdxcXWrguC3LTWWUljfl9negqv5cMPY=; h=From:To:Subject:Date:From; b=fjEnu/6l8If24XpqVU4/n+r0fLrkMAf/hlXt9dRjCHbDOrb9N+790rDQWZ2ypYHEJ R0hyvktwjhQvPRWruiv3DX+d5nZ3ACtZNsz92Camp4jxt0TOlB9lcpg+2UrOldN8b9 labqnCcAwwW8zQKbmchbsShdmQ849rPANaPPrIfs= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Michael Meissner To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc(refs/users/meissner/heads/work013-orig)] libstdc++: Add compile-time checks to__glibcxx_assert [PR 71960] X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/users/meissner/heads/work013-orig X-Git-Oldrev: 8bc0f24d7a20d89383859907b875a26ce59dc6c8 X-Git-Newrev: 10f51543bb81cc953792270b40a9c812049e8b4c Message-Id: <20200901203336.F05453959E71@sourceware.org> Date: Tue, 1 Sep 2020 20:33:36 +0000 (GMT) X-BeenThere: libstdc++-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Sep 2020 20:33:37 -0000 https://gcc.gnu.org/g:10f51543bb81cc953792270b40a9c812049e8b4c commit 10f51543bb81cc953792270b40a9c812049e8b4c Author: Jonathan Wakely Date: Tue Sep 1 20:52:26 2020 +0100 libstdc++: Add compile-time checks to__glibcxx_assert [PR 71960] This change evaluates __glibcxx_assert checks unconditionally when a function is being constant evaluated (when std::is_constant_evaluated() is true). If the check fails, compilation will fail with an error. If the function isn't being constant evaluated, the normal runtime check will be done if enabled by _GLIBCXX_ASSERTIONS or _GLIBCXX_DEBUG, the same as before. Tangentially, the __glibcxx_assert and _GLIBCXX_PARALLEL_ASSERT macros are changed to expand to 'do { } while (false)' when assertions are disabled, instead of expanding to nothing. This avoids -Wempty-body warnings when a disabled assertion is used in an 'if' or 'else' statement e.g. if constexpr (/* precondition is testable */) __glibcxx_assert(precondition); a.C:9:27: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body] 9 | __glibcxx_assert(precondition); | ^ libstdc++-v3/ChangeLog: PR libstdc++/71960 * include/bits/c++config (__glibcxx_assert_impl): Remove do-while so that uses of the macro need to add it. (__glibcxx_assert): Rename macro for runtime assertions to __glibcxx_assert_2. (__glibcxx_assert_1): Define macro for constexpr assertions. (__glibcxx_assert): Define macro for constexpr and runtime assertions. * include/bits/range_access.h (ranges::advance): Remove redundant precondition checks during constant evaluation. * include/parallel/base.h (_GLIBCXX_PARALLEL_ASSERT): Always use do-while in macro expansion. * include/std/ranges (iota_view::iota_view(W, B)): Remove redundant braces. Diff: --- libstdc++-v3/include/bits/c++config | 35 ++++++++++++++++++++++++-------- libstdc++-v3/include/bits/range_access.h | 10 ++------- libstdc++-v3/include/parallel/base.h | 5 +++-- libstdc++-v3/include/std/ranges | 4 +--- 4 files changed, 32 insertions(+), 22 deletions(-) diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config index de28acea6b7..badf9d01a04 100644 --- a/libstdc++-v3/include/bits/c++config +++ b/libstdc++-v3/include/bits/c++config @@ -477,19 +477,16 @@ namespace std __builtin_abort(); } } -#define __glibcxx_assert_impl(_Condition) \ - do \ - { \ - if (! (_Condition)) \ - std::__replacement_assert(__FILE__, __LINE__, __PRETTY_FUNCTION__, \ - #_Condition); \ - } while (false) +#define __glibcxx_assert_impl(_Condition) \ + if (!bool(_Condition)) \ + std::__replacement_assert(__FILE__, __LINE__, __PRETTY_FUNCTION__, \ + #_Condition) #endif #if defined(_GLIBCXX_ASSERTIONS) -# define __glibcxx_assert(_Condition) __glibcxx_assert_impl(_Condition) +# define __glibcxx_assert_2(_Condition) __glibcxx_assert_impl(_Condition) #else -# define __glibcxx_assert(_Condition) +# define __glibcxx_assert_2(_Condition) #endif // Macros for race detectors. @@ -683,6 +680,26 @@ namespace std # endif #endif // GCC +#if _GLIBCXX_HAVE_BUILTIN_IS_CONSTANT_EVALUATED +# define __glibcxx_assert_1(_Condition) \ + if (__builtin_is_constant_evaluated()) \ + { \ + void __failed_assertion(); \ + if (!bool(_Condition)) \ + __failed_assertion(); \ + } \ + else +#else +# define __glibcxx_assert_1(_Condition) +#endif + +# define __glibcxx_assert(_Condition) \ + do { \ + __glibcxx_assert_1(_Condition) \ + { __glibcxx_assert_2(_Condition); } \ + } while (false) + + // PSTL configuration #if __cplusplus >= 201703L diff --git a/libstdc++-v3/include/bits/range_access.h b/libstdc++-v3/include/bits/range_access.h index bafced31ea8..5c5b2fe0c6c 100644 --- a/libstdc++-v3/include/bits/range_access.h +++ b/libstdc++-v3/include/bits/range_access.h @@ -987,10 +987,7 @@ namespace ranges } else { -#ifdef __cpp_lib_is_constant_evaluated - if (std::is_constant_evaluated() && __n < 0) - throw "attempt to decrement a non-bidirectional iterator"; -#endif + // cannot decrement a non-bidirectional iterator __glibcxx_assert(__n >= 0); while (__n-- > 0) ++__it; @@ -1065,10 +1062,7 @@ namespace ranges } else { -#ifdef __cpp_lib_is_constant_evaluated - if (std::is_constant_evaluated() && __n < 0) - throw "attempt to decrement a non-bidirectional iterator"; -#endif + // cannot decrement a non-bidirectional iterator __glibcxx_assert(__n >= 0); return __n; } diff --git a/libstdc++-v3/include/parallel/base.h b/libstdc++-v3/include/parallel/base.h index 0d1c2644e8f..973a2dcd514 100644 --- a/libstdc++-v3/include/parallel/base.h +++ b/libstdc++-v3/include/parallel/base.h @@ -420,9 +420,10 @@ namespace __gnu_parallel } #if _GLIBCXX_PARALLEL_ASSERTIONS && defined(__glibcxx_assert_impl) -#define _GLIBCXX_PARALLEL_ASSERT(_Condition) __glibcxx_assert_impl(_Condition) +# define _GLIBCXX_PARALLEL_ASSERT(_Condition) \ + do { __glibcxx_assert_impl(_Condition); } while (false) #else -#define _GLIBCXX_PARALLEL_ASSERT(_Condition) +# define _GLIBCXX_PARALLEL_ASSERT(_Condition) do { } while (false) #endif } //namespace __gnu_parallel diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges index 2d0017f1750..054ffe85d0f 100644 --- a/libstdc++-v3/include/std/ranges +++ b/libstdc++-v3/include/std/ranges @@ -860,9 +860,7 @@ namespace ranges : _M_value(__value), _M_bound(__bound) { if constexpr (totally_ordered_with<_Winc, _Bound>) - { - __glibcxx_assert( bool(__value <= __bound) ); - } + __glibcxx_assert( bool(__value <= __bound) ); } constexpr _Iterator