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2011-02-15 Yao Qi <yao@codesourcery.com> 

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  <yao@codesourcery.com>

	PR tdep/12352
	* gdb.arch/arm-disp-step.S : New test for str instruction.
	* gdb.arch/arm-disp-step.exp : Likewise
This commit is contained in:
Yao Qi 2011-02-15 14:26:34 +00:00
parent d9492458a1
commit 494e194e77
5 changed files with 104 additions and 11 deletions
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6
gdb/ChangeLog
View File

@ -1,3 +1,9 @@
2011-02-15 Yao Qi <yao@codesourcery.com>
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 <bauerman@br.ibm.com>
* rs6000-tdep.c (IS_EFP_PSEUDOREG): Use correct constant for

29
gdb/arm-tdep.c
View File

@ -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: <temp>
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. */

6
gdb/testsuite/ChangeLog
View File

@ -1,3 +1,9 @@
2011-02-15 Yao Qi <yao@codesourcery.com>
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 <bauerman@br.ibm.com>
* gdb.arch/vsx-regs.exp: Add "vector_register1_vr" and

37
gdb/testsuite/gdb.arch/arm-disp-step.S
View File

@ -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

37
gdb/testsuite/gdb.arch/arm-disp-step.exp
View File

@ -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.