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backtrace.h (fallback_backtrace): Add "0x55 0x8B 0xEC" as another sequence that can indicate a "pushl %ebp... 

* sysdep/i386/backtrace.h (fallback_backtrace): Add "0x55 0x8B 0xEC"
	as another sequence that can indicate a "pushl %ebp; movl %esp, %ebp"
	function prologue.

From-SVN: r116258
This commit is contained in:
Ranjit Mathew 2006-08-19 15:35:11 +00:00
parent 4f8e2b0e6e
commit d58b0443ec
2 changed files with 12 additions and 4 deletions
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6
libjava/ChangeLog
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@ -1,3 +1,9 @@
2006-08-19 Ranjit Mathew <rmathew@gcc.gnu.org>
* sysdep/i386/backtrace.h (fallback_backtrace): Add "0x55 0x8B 0xEC"
as another sequence that can indicate a "pushl %ebp; movl %esp, %ebp"
function prologue.
2006-08-17 H.J. Lu <hongjiu.lu@intel.com> 2006-08-17 H.J. Lu <hongjiu.lu@intel.com>
* Makefile.am (install-exec-hook): Support $(DESTDIR). * Makefile.am (install-exec-hook): Support $(DESTDIR).

10
libjava/sysdep/i386/backtrace.h
View File

@ -71,8 +71,9 @@ fallback_backtrace (_Unwind_Trace_Fn trace_fn, _Jv_UnwindState *state)
/* Try to locate a "pushl %ebp; movl %esp, %ebp" function prologue /* Try to locate a "pushl %ebp; movl %esp, %ebp" function prologue
by scanning backwards at even addresses below the return address. by scanning backwards at even addresses below the return address.
This instruction sequence is encoded as 0x55 0x89 0xE5. We give up This instruction sequence is encoded either as 0x55 0x89 0xE5 or as
if we do not find this sequence even after scanning 1024K of memory. 0x55 0x8B 0xEC. We give up if we do not find this sequence even
after scanning 1024K of memory.
FIXME: This is not robust and will probably give us false positives, FIXME: This is not robust and will probably give us false positives,
but this is about the best we can do if we do not have DWARF-2 unwind but this is about the best we can do if we do not have DWARF-2 unwind
information based exception handling. */ information based exception handling. */
@ -83,8 +84,9 @@ fallback_backtrace (_Unwind_Trace_Fn trace_fn, _Jv_UnwindState *state)
for ( ; scan_addr >= limit_addr; scan_addr -= 2) for ( ; scan_addr >= limit_addr; scan_addr -= 2)
{ {
unsigned char *scan_bytes = (unsigned char *)scan_addr; unsigned char *scan_bytes = (unsigned char *)scan_addr;
if (scan_bytes[0] == 0x55 && scan_bytes[1] == 0x89 if (scan_bytes[0] == 0x55
&& scan_bytes[2] == 0xE5) && ((scan_bytes[1] == 0x89 && scan_bytes[2] == 0xE5)
|| (scan_bytes[1] == 0x8B && scan_bytes[2] == 0xEC)))
{ {
ctx.meth_addr = scan_addr; ctx.meth_addr = scan_addr;
break; break;