[gcc r9-9180] libstdc++: Fix clang analyzer suppression [PR 98605]

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:4aeae11db66c9bce0aadf447e6ff0776a97bfccf

commit r9-9180-g4aeae11db66c9bce0aadf447e6ff0776a97bfccf
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Jan 13 11:03:58 2021 +0000

    libstdc++: Fix clang analyzer suppression [PR 98605]
    
    The fix for PR libstdc++/82481 should only have applied for targets
    where _GLIBCXX_HAVE_TLS is defined. Because it was also done for non-TLS
    targets, it isn't possible to use clang's analyzers on non-TLS targets
    if the code uses <mutex>. This fixes it by using a NOLINT comment on
    the relevant line instead of testing #ifdef __clang_analyzer__ and
    compiling different code when analyzing.
    
    I'm not actually able to reproduce the analyzer warning with the tools
    from Clang 10.0.1 so I'm not going to try to make the suppression more
    specific with NOLINTNEXTLINE(clang-analyzer-code.StackAddressEscape).
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/98605
            * include/std/mutex (call_once): Use NOLINT to suppress clang
            analyzer warnings.
    
    (cherry picked from commit 8d3636923a309074eb19240ebaa30c1a0801eaaf)

Diff:
---
 libstdc++-v3/include/std/mutex | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/libstdc++-v3/include/std/mutex b/libstdc++-v3/include/std/mutex
index dfb5f7eb31a..49dfbbac5cd 100644
--- a/libstdc++-v3/include/std/mutex
+++ b/libstdc++-v3/include/std/mutex
@@ -672,7 +672,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 			std::forward<_Args>(__args)...);
       };
 #ifdef _GLIBCXX_HAVE_TLS
-      __once_callable = std::__addressof(__callable);
+      __once_callable = std::__addressof(__callable); // NOLINT: PR 82481
       __once_call = []{ (*(decltype(__callable)*)__once_callable)(); };
 #else
       unique_lock<mutex> __functor_lock(__get_once_mutex());
@@ -687,12 +687,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
         __set_once_functor_lock_ptr(0);
 #endif
 
-#ifdef __clang_analyzer__
-      // PR libstdc++/82481
-      __once_callable = nullptr;
-      __once_call = nullptr;
-#endif
-
       if (__e)
 	__throw_system_error(__e);
     }