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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> 2008-01-28 Doug Evans <dje@google.com>
* dbxread.c (read_dbx_symtab): Fix indentation. * 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; 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) if (AM33_MODE (gdbarch) == 2)
{ {
/* Determine if any floating point registers are to be saved. /* 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 was actually encountered. As a consequence, ``addr'' would
sometimes be advanced even when no fmov instructions were found. */ sometimes be advanced even when no fmov instructions were found. */
CORE_ADDR restore_addr = addr; CORE_ADDR restore_addr = addr;
int fmov_found = 0;
/* First, look for add -SIZE,sp (i.e. add imm8,sp (0xf8feXX) /* First, look for add -SIZE,sp (i.e. add imm8,sp (0xf8feXX)
or add imm16,sp (0xfafeXXXX) or add imm16,sp (0xfafeXXXX)
@ -715,12 +732,9 @@ mn10300_analyze_prologue (struct gdbarch *gdbarch, struct frame_info *fi,
break; break;
/* An fmov instruction has just been seen. We can /* An fmov instruction has just been seen. We can
now really commit to the pattern match. Set the now really commit to the pattern match. */
address to restore at the end of this speculative
bit of code to the actually address that we've fmov_found = 1;
been incrementing (or not) throughout the
speculation. */
restore_addr = addr;
/* Get the floating point register number from the /* Get the floating point register number from the
2nd and 3rd bytes of the "fmov" instruction: 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; 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 /* If no fmov instructions were found by the above sequence, reset
registers are saved in this prologue. */ the state and pretend that the above bit of code never happened. */
if (!fmov_found)
/* In the pattern match code contained within this block, `restore_addr' {
is set to the starting address at the very beginning and then addr = restore_addr;
iteratively to the next address to start scanning at once the status = read_memory_nobpt (addr, buf, 2);
pattern match has succeeded. Thus `restore_addr' will contain if (status != 0)
the address to rewind to if the pattern match failed. If the goto finish_prologue;
match succeeded, `restore_addr' and `addr' will already have the stack_extra_size = 0;
same value. */ }
addr = restore_addr;
} }
/* Now see if we set up a frame pointer via "mov sp,a3" */ /* Now see if we set up a frame pointer via "mov sp,a3" */