From 494e194e77ee1e03d260268fc132dccf308f223e Mon Sep 17 00:00:00 2001 From: Yao Qi Date: Tue, 15 Feb 2011 14:26:34 +0000 Subject: [PATCH] 2011-02-15 Yao Qi 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. 2011-02-15 Yao Qi PR tdep/12352 * gdb.arch/arm-disp-step.S : New test for str instruction. * gdb.arch/arm-disp-step.exp : Likewise --- gdb/ChangeLog | 6 ++++ gdb/arm-tdep.c | 29 ++++++++++++------- gdb/testsuite/ChangeLog | 6 ++++ gdb/testsuite/gdb.arch/arm-disp-step.S | 37 ++++++++++++++++++++++++ gdb/testsuite/gdb.arch/arm-disp-step.exp | 37 ++++++++++++++++++++++++ 5 files changed, 104 insertions(+), 11 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 10d816f8e01..a02e058fd16 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2011-02-15 Yao Qi + + 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. + 2011-02-15 Thiago Jung Bauermann * rs6000-tdep.c (IS_EFP_PSEUDOREG): Use correct constant for diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c index 9dfbf499e8b..6a279d19e1a 100644 --- a/gdb/arm-tdep.c +++ b/gdb/arm-tdep.c @@ -5930,16 +5930,24 @@ 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: + Before this sequence of instructions: + r0 is the PC value got from displaced_read_reg, so r0 = from + 8; + r2 is the Rn value got from dispalced_read_reg. + + 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, #8 r4 = offset - 8 + Insn5: add r0, r0, r4 r0 = from + 8 + offset - 8 + = from + offset + 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) { @@ -5960,9 +5968,8 @@ 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[4] = 0xe0800004; /* add r0, r0, r4. */ diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 2ce11ab07a7..7b26a012639 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2011-02-15 Yao Qi + + PR tdep/12352 + * gdb.arch/arm-disp-step.S : New test for str instruction. + * gdb.arch/arm-disp-step.exp : Likewise. + 2011-02-15 Thiago Jung Bauermann * gdb.arch/vsx-regs.exp: Add "vector_register1_vr" and diff --git a/gdb/testsuite/gdb.arch/arm-disp-step.S b/gdb/testsuite/gdb.arch/arm-disp-step.S index e1756e72162..fb769743592 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 +122,36 @@ 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] + ldr r0, [sp, #-4] + sub r0, r0, pc + /* compute offset again without displaced stepping. */ + str pc, [sp, #-4] + ldr r1, [sp, #-4] + sub r1, r1, pc + + /* r0 should be equal to r1. */ + cmp r0, r1 + bne pc_offset_wrong + + .global pc_offset_right +pc_offset_right: + b test_str_pc_end + + .global pc_offset_wrong +pc_offset_wrong: + nop + + .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 841bfcec43b..3bea521abb7 100644 --- a/gdb/testsuite/gdb.arch/arm-disp-step.exp +++ b/gdb/testsuite/gdb.arch/arm-disp-step.exp @@ -126,6 +126,42 @@ 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" + + # Set breakpoint on both lables pc_offset_right and pc_offset_wrong + gdb_test "break *pc_offset_right" \ + "Breakpoint.*at.* file .*$srcfile, line.*" \ + "break pc_offset_right" + gdb_test "break *pc_offset_wrong" \ + "Breakpoint.*at.* file .*$srcfile, line.*" \ + "break pc_offset_wrong" + + gdb_continue_to_breakpoint "continue to test_str_pc" \ + ".*str.*pc\,.*\[sp, #-4\].*" + # If breakpoint on lable pc_offset_wrong is hit, that means the offset + # computed in displaced stepping is different from offset computed + # without displaced stepping. Report a failure. + gdb_continue_to_breakpoint "continue to pc_offset_right" \ + ".*b.*test_str_pc_end.*" + gdb_continue_to_breakpoint "continue to test_str_pc_end" \ + ".*bx lr.*" +} + # Get things started. clean_restart ${testfile} @@ -165,6 +201,7 @@ test_ldr_from_pc test_ldm_stm_pc +test_str_pc ########################################## # Done, run program to exit. -- 2.30.2