From: "Marc Poulhiès" <poulhies@adacore.com>
To: gcc-patches@gcc.gnu.org
Cc: Steve Baird <baird@adacore.com>
Subject: [Ada] Enable lock free protected implementation by default
Date: Tue, 6 Sep 2022 09:16:01 +0200 [thread overview]
Message-ID: <20220906071601.GA1280515@poulhies-Precision-5550> (raw)
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In the past, the Lock_Free aspect of a protected type (including an
anonymous type) defaulted to False. In the case where an explicit
"Lock_Free => True" aspect specification would be legal, the aspect now
defaults to True (which means that a lock-free implementation is used to
implement the type's protected operations); this is like the previous
behavior of the compiler with the -gnatd9 switch specified. Support for
the Lock_Free attribute (which should not be confused with the Lock_Free
aspect) is removed.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* debug.adb: Remove comment regarding the -gnatd9 switch.
* doc/gnat_rm/implementation_defined_attributes.rst: Remove all
mention of the Lock_Free attribute.
* gnat_rm.texi, gnat_ugn.texi: Regenerate.
* exp_attr.adb, sem_attr.adb: Remove all mention of the former
Attribute_Lock_Free enumeration element of the Attribute_Id type.
* sem_ch9.adb
(Allows_Lock_Free_Implementation): Remove the Debug_Flag_9 test.
Return False in the case of a protected function whose result type
requires use of the secondary stack.
(Satisfies_Lock_Free_Requirements): This functions checks for
certain constructs and returns False if one is found. In the case
of a protected function, there is no need to check to see if the
protected object is being modified. So it is ok to omit *some*
checks in the case of a protected function. But other checks which
are required (e.g., the test for a reference to a variable that is
not part of the protected object) were being incorrectly omitted.
This could result in accepting "Lock_Free => True" aspect
specifications that should be rejected.
* snames.adb-tmpl: Name_Lock_Free no longer requires special
treatment in Get_Pragma_Id or Is_Pragma_Name (because it is no
longer an attribute name).
* snames.ads-tmpl: Move the declaration of Name_Lock_Free to
reflect the fact that it is no longer the name of an attribute.
Delete Attribute_Lock_Free from the Attribute_Id enumeration type.
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reply other threads:[~2022-09-06 7:16 UTC|newest]
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