OpenE2K
/
binutils-gdb
12
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

2010-10-08 Ulrich Weigand <uweigand@de.ibm.com> 

Daniel Jacobowitz  <dan@codesourcery.com>

	* arm-tdep.c (thumb_in_function_epilogue_p)
	(arm_in_function_epilogue_p): New.
	(arm_gdbarch_init): Install arm_in_function_epilogue_p as
	gdbarch_in_function_epilogue_p callback.
This commit is contained in:
Ulrich Weigand 2010-10-08 13:24:55 +00:00
parent 682ffa1ca8
commit 4024ca9964
2 changed files with 208 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
gdb/ChangeLog
View File

@ -1,3 +1,11 @@
2010-10-08 Ulrich Weigand <uweigand@de.ibm.com>
Daniel Jacobowitz <dan@codesourcery.com>
* arm-tdep.c (thumb_in_function_epilogue_p)
(arm_in_function_epilogue_p): New.
(arm_gdbarch_init): Install arm_in_function_epilogue_p as
gdbarch_in_function_epilogue_p callback.
2010-10-07 Doug Evans <dje@google.com>
* cc-with-index.sh (output_file): Default to a.out.

200
gdb/arm-tdep.c
View File

@ -1706,6 +1706,203 @@ arm_dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
}
}
/* Return true if we are in the function's epilogue, i.e. after the
instruction that destroyed the function's stack frame. */
static int
thumb_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc)
{
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
unsigned int insn, insn2;
int found_return = 0, found_stack_adjust = 0;
CORE_ADDR func_start, func_end;
CORE_ADDR scan_pc;
gdb_byte buf[4];
if (!find_pc_partial_function (pc, NULL, &func_start, &func_end))
return 0;
/* The epilogue is a sequence of instructions along the following lines:
- add stack frame size to SP or FP
- [if frame pointer used] restore SP from FP
- restore registers from SP [may include PC]
- a return-type instruction [if PC wasn't already restored]
In a first pass, we scan forward from the current PC and verify the
instructions we find as compatible with this sequence, ending in a
return instruction.
However, this is not sufficient to distinguish indirect function calls
within a function from indirect tail calls in the epilogue in some cases.
Therefore, if we didn't already find any SP-changing instruction during
forward scan, we add a backward scanning heuristic to ensure we actually
are in the epilogue. */
scan_pc = pc;
while (scan_pc < func_end && !found_return)
{
if (target_read_memory (scan_pc, buf, 2))
break;
scan_pc += 2;
insn = extract_unsigned_integer (buf, 2, byte_order_for_code);
if ((insn & 0xff80) == 0x4700) /* bx <Rm> */
found_return = 1;
else if (insn == 0x46f7) /* mov pc, lr */
found_return = 1;
else if (insn == 0x46bd) /* mov sp, r7 */
found_stack_adjust = 1;
else if ((insn & 0xff00) == 0xb000) /* add sp, imm or sub sp, imm */
found_stack_adjust = 1;
else if ((insn & 0xfe00) == 0xbc00) /* pop <registers> */
{
found_stack_adjust = 1;
if (insn & 0x0100) /* <registers> include PC. */
found_return = 1;
}
else if ((insn & 0xe000) == 0xe000) /* 32-bit Thumb-2 instruction */
{
if (target_read_memory (scan_pc, buf, 2))
break;
scan_pc += 2;
insn2 = extract_unsigned_integer (buf, 2, byte_order_for_code);
if (insn == 0xe8bd) /* ldm.w sp!, <registers> */
{
found_stack_adjust = 1;
if (insn2 & 0x8000) /* <registers> include PC. */
found_return = 1;
}
else if (insn == 0xf85d /* ldr.w <Rt>, [sp], #4 */
&& (insn2 & 0x0fff) == 0x0b04)
{
found_stack_adjust = 1;
if ((insn2 & 0xf000) == 0xf000) /* <Rt> is PC. */
found_return = 1;
}
else if ((insn & 0xffbf) == 0xecbd /* vldm sp!, <list> */
&& (insn2 & 0x0e00) == 0x0a00)
found_stack_adjust = 1;
else
break;
}
else
break;
}
if (!found_return)
return 0;
/* Since any instruction in the epilogue sequence, with the possible
exception of return itself, updates the stack pointer, we need to
scan backwards for at most one instruction. Try either a 16-bit or
a 32-bit instruction. This is just a heuristic, so we do not worry
too much about false positives.*/
if (!found_stack_adjust)
{
if (pc - 4 < func_start)
return 0;
if (target_read_memory (pc - 4, buf, 4))
return 0;
insn = extract_unsigned_integer (buf, 2, byte_order_for_code);
insn2 = extract_unsigned_integer (buf + 2, 2, byte_order_for_code);
if (insn2 == 0x46bd) /* mov sp, r7 */
found_stack_adjust = 1;
else if ((insn2 & 0xff00) == 0xb000) /* add sp, imm or sub sp, imm */
found_stack_adjust = 1;
else if ((insn2 & 0xff00) == 0xbc00) /* pop <registers> without PC */
found_stack_adjust = 1;
else if (insn == 0xe8bd) /* ldm.w sp!, <registers> */
found_stack_adjust = 1;
else if (insn == 0xf85d /* ldr.w <Rt>, [sp], #4 */
&& (insn2 & 0x0fff) == 0x0b04)
found_stack_adjust = 1;
else if ((insn & 0xffbf) == 0xecbd /* vldm sp!, <list> */
&& (insn2 & 0x0e00) == 0x0a00)
found_stack_adjust = 1;
}
return found_stack_adjust;
}
/* Return true if we are in the function's epilogue, i.e. after the
instruction that destroyed the function's stack frame. */
static int
arm_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc)
{
enum bfd_endian byte_order_for_code = gdbarch_byte_order_for_code (gdbarch);
unsigned int insn;
int found_return, found_stack_adjust;
CORE_ADDR func_start, func_end;
if (arm_pc_is_thumb (gdbarch, pc))
return thumb_in_function_epilogue_p (gdbarch, pc);
if (!find_pc_partial_function (pc, NULL, &func_start, &func_end))
return 0;
/* We are in the epilogue if the previous instruction was a stack
adjustment and the next instruction is a possible return (bx, mov
pc, or pop). We could have to scan backwards to find the stack
adjustment, or forwards to find the return, but this is a decent
approximation. First scan forwards. */
found_return = 0;
insn = read_memory_unsigned_integer (pc, 4, byte_order_for_code);
if (bits (insn, 28, 31) != INST_NV)
{
if ((insn & 0x0ffffff0) == 0x012fff10)
/* BX. */
found_return = 1;
else if ((insn & 0x0ffffff0) == 0x01a0f000)
/* MOV PC. */
found_return = 1;
else if ((insn & 0x0fff0000) == 0x08bd0000
&& (insn & 0x0000c000) != 0)
/* POP (LDMIA), including PC or LR. */
found_return = 1;
}
if (!found_return)
return 0;
/* Scan backwards. This is just a heuristic, so do not worry about
false positives from mode changes. */
if (pc < func_start + 4)
return 0;
insn = read_memory_unsigned_integer (pc - 4, 4, byte_order_for_code);
if (bits (insn, 28, 31) != INST_NV)
{
if ((insn & 0x0df0f000) == 0x0080d000)
/* ADD SP (register or immediate). */
found_stack_adjust = 1;
else if ((insn & 0x0df0f000) == 0x0040d000)
/* SUB SP (register or immediate). */
found_stack_adjust = 1;
else if ((insn & 0x0ffffff0) == 0x01a0d000)
/* MOV SP. */
found_return = 1;
else if ((insn & 0x0fff0000) == 0x08bd0000)
/* POP (LDMIA). */
found_stack_adjust = 1;
}
if (found_stack_adjust)
return 1;
return 0;
}
/* When arguments must be pushed onto the stack, they go on in reverse
order. The code below implements a FILO (stack) to do this. */
@ -6881,6 +7078,9 @@ arm_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
/* Advance PC across function entry code. */
set_gdbarch_skip_prologue (gdbarch, arm_skip_prologue);
/* Detect whether PC is in function epilogue. */
set_gdbarch_in_function_epilogue_p (gdbarch, arm_in_function_epilogue_p);
/* Skip trampolines. */
set_gdbarch_skip_trampoline_code (gdbarch, arm_skip_stub);