From: Jonathan Wakely <jwakely@redhat.com>
Date: Wed, 13 Jan 2021 11:03:58 +0000 (+0000)
Subject: libstdc++: Fix clang analyzer suppression [PR 98605]
X-Git-Tag: releases/gcc-10.3.0~397
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8d3636923a309074eb19240ebaa30c1a0801eaaf;p=thirdparty%2Fgcc.git

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.
---

diff --git a/libstdc++-v3/include/std/mutex b/libstdc++-v3/include/std/mutex
index 12b7e548d179..3c619f87040b 100644
--- a/libstdc++-v3/include/std/mutex
+++ b/libstdc++-v3/include/std/mutex
@@ -718,7 +718,7 @@ _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());
@@ -733,12 +733,6 @@ _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);
     }