From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9159 invoked by alias); 10 Feb 2011 06:19:21 -0000 Received: (qmail 9147 invoked by uid 22791); 10 Feb 2011 06:19:20 -0000 X-SWARE-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 10 Feb 2011 06:19:09 +0000 Received: (qmail 3372 invoked from network); 10 Feb 2011 06:19:07 -0000 Received: from unknown (HELO ?192.168.0.101?) (yao@127.0.0.2) by mail.codesourcery.com with ESMTPA; 10 Feb 2011 06:19:07 -0000 Message-ID: <4D538352.8090303@codesourcery.com> Date: Thu, 10 Feb 2011 06:19:00 -0000 From: Yao Qi User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101208 Lightning/1.0b2 Thunderbird/3.1.7 MIME-Version: 1.0 To: Ulrich Weigand CC: Richard Earnshaw , gdb-patches@sourceware.org, julian@codesourcery.com Subject: Re: [patch] Fix PR tdep/12352: Handle str pc, [Rd, #imm] in displaced stepping References: <201102091351.p19Dp0qB002862@d06av02.portsmouth.uk.ibm.com> In-Reply-To: <201102091351.p19Dp0qB002862@d06av02.portsmouth.uk.ibm.com> Content-Type: multipart/mixed; boundary="------------050103000307080700090109" X-IsSubscribed: yes 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: 2011-02/txt/msg00192.txt.bz2 This is a multi-part message in MIME format. --------------050103000307080700090109 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Content-length: 933 On 02/09/2011 09:51 PM, Ulrich Weigand wrote: > Yes, I'm aware of that. However, my understanding is that this special > definition of STR PC applies to *all* variants of STR, including PUSH > (PUSH { PC } is just another mnemonic for STR PC, [ SP, #-4 ]). > Oh, I understand your points now. You are right. I didn't realize that before. > If you look at the formal semantics definition in the ARM reference > manual, all variants of STR (including PUSH) use the pseudo-code macro > "PCStoreValue" to implement storing of the PC, which is defined to > include the implementation-defined constant ... A new patch is attached in which PUSH/POP is used. I also noticed that Insn4 should be 'add r4, r4, #16' rather than 'add r4, r4, #8', explained in the comments. After that, the offset of my board is 8. Run patched arm-disp-step.exp on native GDB configured as armv7l-unknown-linux-gnueabi. No failures. -- Yao (齐尧) --------------050103000307080700090109 Content-Type: text/x-patch; name="pr12352-0210.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="pr12352-0210.patch" Content-length: 4356 gdb/ PR tdep/12352 * arm-tdep.c (copy_ldr_str_ldrb_strb): Replace PC with SP in order to store PC value on stack instead of text section. gdb/testsuite/ PR tdep/12352 * gdb.arch/arm-disp-step.S : New test for str instruction. * gdb.arch/arm-disp-step.exp : Likewise. diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c index 1f05b7a..7591b62 100644 --- a/gdb/arm-tdep.c +++ b/gdb/arm-tdep.c @@ -5146,16 +5146,19 @@ copy_ldr_str_ldrb_strb (struct gdbarch *gdbarch, uint32_t insn, /* To write PC we can do: - scratch+0: str pc, temp (*temp = scratch + 8 + offset) - scratch+4: ldr r4, temp - scratch+8: sub r4, r4, pc (r4 = scratch + 8 + offset - scratch - 8 - 8) - scratch+12: add r4, r4, #8 (r4 = offset) - scratch+16: add r0, r0, r4 - scratch+20: str r0, [r2, #imm] (or str r0, [r2, r3]) - scratch+24: + Insn1: push {pc} Write address of STR instruction + offset on stack + Insn2: pop {r4} Read it back from stack, r4 = addr(Insn1) + offset + Insn3: sub r4, r4, pc r4 = addr(Insn1) + offset - pc + = addr(Insn1) + offset - addr(Insn3) - 8 + = offset - 16 + Insn4: add r4, r4, #16 r4 = offset + Insn5: add r0, r0, r4 + Insn6: str r0, [r2, #imm] (or str r0, [r2, r3]) Otherwise we don't know what value to write for PC, since the offset is - architecture-dependent (sometimes PC+8, sometimes PC+12). */ + architecture-dependent (sometimes PC+8, sometimes PC+12). More details + of this can be found in Section "Saving from r15" in + http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0204g/Cihbjifh.html */ if (load || rt != 15) { @@ -5176,11 +5179,10 @@ copy_ldr_str_ldrb_strb (struct gdbarch *gdbarch, uint32_t insn, { /* We need to use r4 as scratch. Make sure it's restored afterwards. */ dsc->u.ldst.restore_r4 = 1; - - dsc->modinsn[0] = 0xe58ff014; /* str pc, [pc, #20]. */ - dsc->modinsn[1] = 0xe59f4010; /* ldr r4, [pc, #16]. */ + dsc->modinsn[0] = 0xe92d8000; /* push {pc} */ + dsc->modinsn[1] = 0xe8bd0010; /* pop {r4} */ dsc->modinsn[2] = 0xe044400f; /* sub r4, r4, pc. */ - dsc->modinsn[3] = 0xe2844008; /* add r4, r4, #8. */ + dsc->modinsn[3] = 0xe2844010; /* add r4, r4, #16. */ dsc->modinsn[4] = 0xe0800004; /* add r0, r0, r4. */ /* As above. */ diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.S b/gdb/testsuite/gdb.arch/arm-disp-step.S index d748718..1aa7df1 100644 --- a/gdb/testsuite/gdb.arch/arm-disp-step.S +++ b/gdb/testsuite/gdb.arch/arm-disp-step.S @@ -48,6 +48,10 @@ test_ret_end: bl test_ldm_stm_pc #endif + /* Test str in ARM mode and Thumb-2 */ +#if !defined(__thumb__) + bl test_str_pc +#endif /* Return */ mov sp, r7 sub sp, sp, #4 @@ -118,3 +122,17 @@ test_ldm_stm_pc_ret: .word test_ldm_stm_pc_ret .size test_ldm_stm_pc, .-test_ldm_stm_pc #endif + +#if !defined(__thumb__) +#if defined (__thumb2__) + .code 16 + .thumb_func +#endif + .global test_str_pc + .type test_str_pc, %function +test_str_pc: + str pc, [sp, #-4] + .global test_str_pc_end +test_str_pc_end: + bx lr +#endif diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.exp b/gdb/testsuite/gdb.arch/arm-disp-step.exp index 826f728..f2df388 100644 --- a/gdb/testsuite/gdb.arch/arm-disp-step.exp +++ b/gdb/testsuite/gdb.arch/arm-disp-step.exp @@ -126,6 +126,29 @@ proc test_ldr_from_pc {} { ".*bx lr.*" } +########################################### + +proc test_str_pc {} { + global srcfile + gdb_test_multiple "break *test_str_pc" "break test_str_pc" { + -re "Breakpoint.*at.* file .*$srcfile, line.*" { + pass "break test_str_pc" + } + -re "No symbol.*" { + pass "break test_str_pc" + return + } + } + gdb_test "break *test_str_pc_end" \ + "Breakpoint.*at.* file .*$srcfile, line.*" \ + "break test_str_pc_end" + + gdb_continue_to_breakpoint "continue to test_str_pc" \ + ".*str.*pc\,.*\[sp, #-4\].*" + gdb_continue_to_breakpoint "continue to test_str_pc_end" \ + ".*bx lr.*" +} + # Get things started. clean_restart ${testfile} @@ -165,6 +188,7 @@ test_ldr_from_pc test_ldm_stm_pc +test_str_pc ########################################## # Done, run program to exit. --------------050103000307080700090109--