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* mn10300-tdep.c (mn10300_analyze_prologue): Check for an

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instruction pattern that appears frequently in position
	independent code.  Fix bug in code which looks for "fmov" and
	backtracks if no "fmov" is found.
This commit is contained in:
Kevin Buettner 2008-01-29 00:15:10 +00:00
parent f1e8e64f70
commit 8384563051
2 changed files with 37 additions and 27 deletions
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7
gdb/ChangeLog
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@ -1,3 +1,10 @@
2008-01-28 Kevin Buettner <kevinb@redhat.com>
* mn10300-tdep.c (mn10300_analyze_prologue): Check for an
instruction pattern that appears frequently in position
independent code. Fix bug in code which looks for "fmov" and
backtracks if no "fmov" is found.
2008-01-28 Doug Evans <dje@google.com>
* dbxread.c (read_dbx_symtab): Fix indentation.

57
gdb/mn10300-tdep.c
View file

@ -608,6 +608,22 @@ mn10300_analyze_prologue (struct gdbarch *gdbarch, struct frame_info *fi,
goto finish_prologue;
}
/* Check for "mov pc, a2", an instruction found in optimized, position
independent code. Skip it if found. */
if (buf[0] == 0xf0 && buf[1] == 0x2e)
{
addr += 2;
/* Quit now if we're beyond the stop point. */
if (addr >= stop)
goto finish_prologue;
/* Get the next two bytes so the prologue scan can continue. */
status = read_memory_nobpt (addr, buf, 2);
if (status != 0)
goto finish_prologue;
}
if (AM33_MODE (gdbarch) == 2)
{
/* Determine if any floating point registers are to be saved.
@ -635,6 +651,7 @@ mn10300_analyze_prologue (struct gdbarch *gdbarch, struct frame_info *fi,
was actually encountered. As a consequence, ``addr'' would
sometimes be advanced even when no fmov instructions were found. */
CORE_ADDR restore_addr = addr;
int fmov_found = 0;
/* First, look for add -SIZE,sp (i.e. add imm8,sp (0xf8feXX)
or add imm16,sp (0xfafeXXXX)
@ -715,12 +732,9 @@ mn10300_analyze_prologue (struct gdbarch *gdbarch, struct frame_info *fi,
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;
now really commit to the pattern match. */
fmov_found = 1;
/* Get the floating point register number from the
2nd and 3rd bytes of the "fmov" instruction:
@ -739,29 +753,18 @@ mn10300_analyze_prologue (struct gdbarch *gdbarch, struct frame_info *fi,
imm_size = (buf[0] == 0xf9) ? 3 : 4;
}
}
else
{
/* 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;
}
}
/* else the prologue consists entirely of an "add -SIZE,sp"
instruction. Handle this below. */
}
/* else no "add -SIZE,sp" was found indicating no floating point
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;
/* If no fmov instructions were found by the above sequence, reset
the state and pretend that the above bit of code never happened. */
if (!fmov_found)
{
addr = restore_addr;
status = read_memory_nobpt (addr, buf, 2);
if (status != 0)
goto finish_prologue;
stack_extra_size = 0;
}
}
/* Now see if we set up a frame pointer via "mov sp,a3" */