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* mn10300-tdep.c (mn10300_analyze_prologue): Implement backtrack

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out of pattern match by saving relevant state.  Fix stack size
	adjustment bug.
This commit is contained in:
Kevin Buettner 2006-02-28 22:28:21 +00:00
parent f9d4ad2a13
commit e92e42f575
2 changed files with 41 additions and 7 deletions
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6
gdb/ChangeLog
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@ -1,3 +1,9 @@
2006-02-28 Kevin Buettner <kevinb@redhat.com>
* mn10300-tdep.c (mn10300_analyze_prologue): Implement backtrack
out of pattern match by saving relevant state. Fix stack size
adjustment bug.
2006-02-28 Alexandre Oliva <aoliva@redhat.com>
* solib-svr4.h (struct link_map_offsets): Add l_ld_offset and

42
gdb/mn10300-tdep.c
View file

@ -620,6 +620,17 @@ mn10300_analyze_prologue (struct frame_info *fi,
[mov sp,a3] [mov sp,a3]
[add -SIZE2,sp] [add -SIZE2,sp] */
/* Remember the address at which we started in the event that we
don't ultimately find an fmov instruction. Once we're certain
that we matched one of the above patterns, we'll set
``restore_addr'' to the appropriate value. Note: At one time
in the past, this code attempted to not adjust ``addr'' until
there was a fair degree of certainty that the pattern would be
matched. However, that code did not wait until an fmov instruction
was actually encountered. As a consequence, ``addr'' would
sometimes be advanced even when no fmov instructions were found. */
CORE_ADDR restore_addr = addr;
/* First, look for add -SIZE,sp (i.e. add imm8,sp (0xf8feXX)
or add imm16,sp (0xfafeXXXX)
or add imm32,sp (0xfcfeXXXXXXXX)) */
@ -651,10 +662,10 @@ mn10300_analyze_prologue (struct frame_info *fi,
This is a one byte instruction: mov sp,aN = 0011 11XX
where XX is the register number.
Skip this instruction by incrementing addr. (We're
committed now.) The "fmov" instructions will have the
form "fmov fs#,(aN+)" in this case, but that will not
necessitate a change in the "fmov" parsing logic below. */
Skip this instruction by incrementing addr. The "fmov"
instructions will have the form "fmov fs#,(aN+)" in this
case, but that will not necessitate a change in the
"fmov" parsing logic below. */
addr++;
@ -698,6 +709,14 @@ mn10300_analyze_prologue (struct frame_info *fi,
if (buf[0] != 0xf9 && buf[0] != 0xfb)
break;
/* An fmov instruction has just been seen. We can
now really commit to the pattern match. Set the
address to restore at the end of this speculative
bit of code to the actually address that we've
been incrementing (or not) throughout the
speculation. */
restore_addr = addr;
/* Get the floating point register number from the
2nd and 3rd bytes of the "fmov" instruction:
Machine Code: 0000 00X0 YYYY 0000 =>
@ -719,6 +738,7 @@ mn10300_analyze_prologue (struct frame_info *fi,
{
/* No "fmov" was found. Reread the two bytes at the original
"addr" to reset the state. */
addr = restore_addr;
if (!safe_frame_unwind_memory (fi, addr, buf, 2))
goto finish_prologue;
}
@ -727,8 +747,16 @@ mn10300_analyze_prologue (struct frame_info *fi,
instruction. Handle this below. */
}
/* else no "add -SIZE,sp" was found indicating no floating point
registers are saved in this prologue. Do not increment addr. Pretend
this bit of code never happened. */
registers are saved in this prologue. */
/* In the pattern match code contained within this block, `restore_addr'
is set to the starting address at the very beginning and then
iteratively to the next address to start scanning at once the
pattern match has succeeded. Thus `restore_addr' will contain
the address to rewind to if the pattern match failed. If the
match succeeded, `restore_addr' and `addr' will already have the
same value. */
addr = restore_addr;
}
/* Now see if we set up a frame pointer via "mov sp,a3" */
@ -777,7 +805,7 @@ mn10300_analyze_prologue (struct frame_info *fi,
goto finish_prologue;
/* Note the size of the stack. */
stack_extra_size += extract_signed_integer (buf, imm_size);
stack_extra_size -= extract_signed_integer (buf, imm_size);
/* We just consumed 2 + imm_size bytes. */
addr += 2 + imm_size;