From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2140) id CCC113858414; Fri, 23 Jun 2023 20:12:56 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org CCC113858414 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1687551176; bh=3bSlYk0rIQdjnE+K4A0YeMBa4LxE8W2BMXmU0Bc5Jfg=; h=From:To:Subject:Date:From; b=mDe6hg4cE/DJbqpHHtKika59nF13FbpOHUAHtAivVOEKYCJ+3OB81qiVHVKy/aHrv HbdfanKQobd2yAORsZULEPWMVaPFspt9rgcPlHUk9T0508NSP1WkwN9xii4B/FV/5r WOnsTYw65mErxorAhAMGiTQzfEWwQlOpBXddNokQ= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Alexandre Oliva To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] Expose expected_throw attribute X-Act-Checkin: gcc X-Git-Author: Alexandre Oliva X-Git-Refname: refs/users/aoliva/heads/testme X-Git-Oldrev: db3d339cd885db8d2468d944b4039f20281e5995 X-Git-Newrev: 14289a5cb40c747a04b6e645b3ace30a3937a195 Message-Id: <20230623201256.CCC113858414@sourceware.org> Date: Fri, 23 Jun 2023 20:12:56 +0000 (GMT) List-Id: https://gcc.gnu.org/g:14289a5cb40c747a04b6e645b3ace30a3937a195 commit 14289a5cb40c747a04b6e645b3ace30a3937a195 Author: Alexandre Oliva Date: Fri Jun 23 17:10:05 2023 -0300 Expose expected_throw attribute Mark exception-raising subprograms with expected_throw attribute. Document the use of the attribute in Control Flow Redundancy. for gcc/ada/ChangeLog * libgnat/a-except.ads (Raise_Exception): Mark expected_throw. (Reraise_Occurrence): Likewise. (Raise_Exception_Always): Likewise. (Raise_From_Controlled_Operation): Likewise. (Reraise_Occurrence_Always): Likewise. (Reraise_Occurrence_No_Defer): Likewise. * doc/gnat_rm/security_hardening_features.rt (Control Flow Hardening): Note the influence of expected_throw. Diff: --- gcc/ada/doc/gnat_rm/security_hardening_features.rst | 4 +++- gcc/ada/libgnat/a-except.ads | 8 ++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) diff --git a/gcc/ada/doc/gnat_rm/security_hardening_features.rst b/gcc/ada/doc/gnat_rm/security_hardening_features.rst index 2eddf206763..e1de80d072b 100644 --- a/gcc/ada/doc/gnat_rm/security_hardening_features.rst +++ b/gcc/ada/doc/gnat_rm/security_hardening_features.rst @@ -489,7 +489,9 @@ gets modified as follows: Verification may also be performed before No_Return calls, whether all of them, with :switch:`-fhardcfr-check-noreturn-calls=always`; all but -internal subprograms involved in exception-raising or -reraising, with +internal subprograms involved in exception-raising or -reraising or +subprograms explicitly marked with both :samp:`No_Return` and +:samp:`Machine_Attribute` :samp:`expected_throw` pragmas, with :switch:`-fhardcfr-check-noreturn-calls=no-xthrow` (default); only nothrow ones, with :switch:`-fhardcfr-check-noreturn-calls=nothrow`; or none, with :switch:`-fhardcfr-check-noreturn-calls=never`. diff --git a/gcc/ada/libgnat/a-except.ads b/gcc/ada/libgnat/a-except.ads index 7949b5907b6..897c68a6101 100644 --- a/gcc/ada/libgnat/a-except.ads +++ b/gcc/ada/libgnat/a-except.ads @@ -79,11 +79,13 @@ package Ada.Exceptions is procedure Raise_Exception (E : Exception_Id; Message : String := ""); pragma No_Return (Raise_Exception); + pragma Machine_Attribute (Raise_Exception, "expected_throw"); -- Note: In accordance with AI-466, CE is raised if E = Null_Id function Exception_Message (X : Exception_Occurrence) return String; procedure Reraise_Occurrence (X : Exception_Occurrence); + pragma Machine_Attribute (Reraise_Occurrence, "expected_throw"); -- Note: it would be really nice to give a pragma No_Return for this -- procedure, but it would be wrong, since Reraise_Occurrence does return -- if the argument is the null exception occurrence. See also procedure @@ -177,6 +179,7 @@ private procedure Raise_Exception_Always (E : Exception_Id; Message : String := ""); pragma No_Return (Raise_Exception_Always); + pragma Machine_Attribute (Raise_Exception_Always, "expected_throw"); pragma Export (Ada, Raise_Exception_Always, "__gnat_raise_exception"); -- This differs from Raise_Exception only in that the caller has determined -- that for sure the parameter E is not null, and that therefore no check @@ -195,6 +198,9 @@ private "__gnat_raise_from_controlled_operation"); -- Raise Program_Error, providing information about X (an exception raised -- during a controlled operation) in the exception message. + pragma Machine_Attribute (Raise_From_Controlled_Operation, + "expected_throw"); + -- Mark it like internal exception-raising subprograms procedure Reraise_Library_Exception_If_Any; pragma Export @@ -205,6 +211,7 @@ private procedure Reraise_Occurrence_Always (X : Exception_Occurrence); pragma No_Return (Reraise_Occurrence_Always); + pragma Machine_Attribute (Reraise_Occurrence_Always, "expected_throw"); -- This differs from Raise_Occurrence only in that the caller guarantees -- that for sure the parameter X is not the null occurrence, and that -- therefore this procedure cannot return. The expander uses this routine @@ -212,6 +219,7 @@ private procedure Reraise_Occurrence_No_Defer (X : Exception_Occurrence); pragma No_Return (Reraise_Occurrence_No_Defer); + pragma Machine_Attribute (Reraise_Occurrence_No_Defer, "expected_throw"); -- Exactly like Reraise_Occurrence, except that abort is not deferred -- before the call and the parameter X is known not to be the null -- occurrence. This is used in generated code when it is known that abort