From patchwork Fri Dec 12 21:50:56 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kratochvil X-Patchwork-Id: 4225 Received: (qmail 14401 invoked by alias); 12 Dec 2014 21:51:04 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Delivered-To: mailing list gdb-patches@sourceware.org Received: (qmail 14390 invoked by uid 89); 12 Dec 2014 21:51:04 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.9 required=5.0 tests=AWL, BAYES_00, SPF_HELO_PASS, SPF_PASS, T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Fri, 12 Dec 2014 21:51:01 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sBCLp06m008189 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Fri, 12 Dec 2014 16:51:00 -0500 Received: from host2.jankratochvil.net (ovpn-116-142.ams2.redhat.com [10.36.116.142]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id sBCLou3c007051 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=NO) for ; Fri, 12 Dec 2014 16:50:59 -0500 Date: Fri, 12 Dec 2014 22:50:56 +0100 From: Jan Kratochvil To: gdb-patches@sourceware.org Subject: [patch] compile: Fix function pointers Message-ID: <20141212215056.GA2003@host2.jankratochvil.net> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) X-IsSubscribed: yes Hi, originally posted in the same form as: [patch 15/14] GDB/GCC compile function pointers [Re: [PATCH v4 00/14] let gdb reuse gcc's C compiler] https://sourceware.org/ml/gdb-patches/2014-12/msg00148.html Message-ID: <20141205182925.GA25151@host2.jankratochvil.net> TBH while I always comment reasons for each of the compilation options in reality I tried them all and chose that combination that needs the most simple compile/compile-object-load.c (ld.so emulation) implementation. So this is a formal request for review/approval as the main patchset is now checked in. Thanks, Jan gdb/ChangeLog 2014-12-12 Jan Kratochvil * compile/compile.c (_initialize_compile): Use -fPIE for compile_args. gdb/testsuite/ChangeLog 2014-12-12 Jan Kratochvil * gdb.compile/compile.exp (pointer to jit function): New test. diff --git a/gdb/compile/compile.c b/gdb/compile/compile.c index 6d3d16e..bb6705f 100644 --- a/gdb/compile/compile.c +++ b/gdb/compile/compile.c @@ -636,12 +636,13 @@ String quoting is parsed like in shell, for example:\n\ /* Override flags possibly coming from DW_AT_producer. */ compile_args = xstrdup ("-O0 -gdwarf-4" - /* We use -fPIC Otherwise GDB would need to reserve space large enough for + /* We use -fPIE Otherwise GDB would need to reserve space large enough for any object file in the inferior in advance to get the final address when to link the object file to and additionally the default system linker script would need to be modified so that one can specify there the - absolute target address. */ - " -fPIC" + absolute target address. + -fPIC is not used at is would require from GDB to generate .got. */ + " -fPIE" /* We don't want warnings. */ " -w" /* Override CU's possible -fstack-protector-strong. */ diff --git a/gdb/testsuite/gdb.compile/compile.exp b/gdb/testsuite/gdb.compile/compile.exp index d0dd791..fb8b390 100644 --- a/gdb/testsuite/gdb.compile/compile.exp +++ b/gdb/testsuite/gdb.compile/compile.exp @@ -259,6 +259,11 @@ gdb_test_no_output "end" "compile code -r multiline 4" gdb_test "print 'compile.c'::globalshadow" " = 77000" \ "check globalshadow with -r" +# Test GOT vs. resolving jit function pointers. + +gdb_test_no_output "compile -raw -- int func(){return 21;} _gdb_expr(){int (*funcp)()=func; if (funcp()!=21) abort();}" \ + "pointer to jit function" + # # Test the case where the registers structure would not normally have # any fields.