From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4528 invoked by alias); 3 May 2012 22:03:08 -0000 Received: (qmail 4495 invoked by uid 22791); 3 May 2012 22:03:03 -0000 X-SWARE-Spam-Status: No, hits=-3.5 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,RCVD_IN_HOSTKARMA_NO,RCVD_IN_HOSTKARMA_W,RCVD_IN_HOSTKARMA_WL,TW_EG X-Spam-Check-By: sourceware.org Received: from rock.gnat.com (HELO rock.gnat.com) (205.232.38.15) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 03 May 2012 22:02:50 +0000 Received: from localhost (localhost.localdomain [127.0.0.1]) by filtered-rock.gnat.com (Postfix) with ESMTP id EE06A1C6CAA for ; Thu, 3 May 2012 18:02:49 -0400 (EDT) Received: from rock.gnat.com ([127.0.0.1]) by localhost (rock.gnat.com [127.0.0.1]) (amavisd-new, port 10024) with LMTP id Bo4eUM4s9pl1 for ; Thu, 3 May 2012 18:02:49 -0400 (EDT) Received: from joel.gnat.com (localhost.localdomain [127.0.0.1]) by rock.gnat.com (Postfix) with ESMTP id B52E61C6CA9 for ; Thu, 3 May 2012 18:02:49 -0400 (EDT) Received: by joel.gnat.com (Postfix, from userid 1000) id 46A84145616; Thu, 3 May 2012 15:02:38 -0700 (PDT) Date: Thu, 03 May 2012 22:03:00 -0000 From: Joel Brobecker To: gdb-patches@sourceware.org Subject: Re: [RFA 1/2] mips: Switch inferior function calls to ON_STACK method. Message-ID: <20120503220238.GL15555@adacore.com> References: <1336071802-13599-1-git-send-email-brobecker@adacore.com> <1336071802-13599-2-git-send-email-brobecker@adacore.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="y0ulUmNC+osPPQO6" Content-Disposition: inline In-Reply-To: <1336071802-13599-2-git-send-email-brobecker@adacore.com> User-Agent: Mutt/1.5.20 (2009-06-14) Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2012-05/txt/msg00110.txt.bz2 --y0ulUmNC+osPPQO6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-length: 332 > gdb/ChangeLog: > > * mips-tdep.c (mips_push_dummy_code): New function. > (mips_gdbarch_init): Set the gdbarch call_dummy_location to > ON_STACK and install mips_push_dummy_code as our gdbarch > push_dummy_code routine. Second version of this patch with Mark's style comments addressed. -- Joel --y0ulUmNC+osPPQO6 Content-Type: text/x-diff; charset=us-ascii Content-Disposition: attachment; filename="mips-on-stack-v2.diff" Content-length: 2787 commit d7f93872c27075342da02ab2ee57062d8b9511c9 Author: Joel Brobecker Date: Wed May 2 20:39:57 2012 -0400 mips: Switch inferior function calls to ON_STACK method. This patch switches the mips code to use the ON_STACK method for function calls instead of AT_SYMBOL, which we want to remove. gdb/ChangeLog: * mips-tdep.c (mips_push_dummy_code): New function. (mips_gdbarch_init): Set the gdbarch call_dummy_location to ON_STACK and install mips_push_dummy_code as our gdbarch push_dummy_code routine. diff --git a/gdb/mips-tdep.c b/gdb/mips-tdep.c index 9a3c7fb..5faf114 100644 --- a/gdb/mips-tdep.c +++ b/gdb/mips-tdep.c @@ -3009,6 +3009,37 @@ mips_frame_align (struct gdbarch *gdbarch, CORE_ADDR addr) return align_down (addr, 16); } +/* Implement the push_dummy_code gdbarch method for mips targets. */ + +static CORE_ADDR +mips_push_dummy_code (struct gdbarch *gdbarch, CORE_ADDR sp, + CORE_ADDR funaddr, struct value **args, + int nargs, struct type *value_type, + CORE_ADDR *real_pc, CORE_ADDR *bp_addr, + struct regcache *regcache) +{ + int bp_len; + gdb_byte null_insn[4] = { 0 }; + + *bp_addr = mips_frame_align (gdbarch, sp); + gdbarch_breakpoint_from_pc (gdbarch, bp_addr, &bp_len); + + /* The breakpoint layer automatically adjusts the address of + breakpoints inserted in a branch delay slot. With enough + bad luck, the 4 bytes located just before our breakpoint + instruction could look like a branch instruction, and thus + trigger the adjustement, and break the function call entirely. + So, we reserve those 4 bytes and write a null instruction + to prevent that from happening. */ + write_memory (*bp_addr - bp_len, null_insn, sizeof (null_insn)); + sp = mips_frame_align (gdbarch, *bp_addr - 2 * bp_len); + + /* Inferior resumes at the function entry point. */ + *real_pc = funaddr; + + return sp; +} + static CORE_ADDR mips_eabi_push_dummy_call (struct gdbarch *gdbarch, struct value *function, struct regcache *regcache, CORE_ADDR bp_addr, @@ -6906,10 +6937,8 @@ mips_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches) /* MIPS version of CALL_DUMMY. */ - /* NOTE: cagney/2003-08-05: Eventually call dummy location will be - replaced by a command, and all targets will default to on stack - (regardless of the stack's execute status). */ - set_gdbarch_call_dummy_location (gdbarch, AT_SYMBOL); + set_gdbarch_call_dummy_location (gdbarch, ON_STACK); + set_gdbarch_push_dummy_code (gdbarch, mips_push_dummy_code); set_gdbarch_frame_align (gdbarch, mips_frame_align); set_gdbarch_convert_register_p (gdbarch, mips_convert_register_p); --y0ulUmNC+osPPQO6--