mirror of git://gcc.gnu.org/git/gcc.git
124 lines
4.4 KiB
C
124 lines
4.4 KiB
C
// backtrace.h - Fallback backtrace implementation. i386 implementation.
|
|
|
|
/* Copyright (C) 2005, 2006 Free Software Foundation
|
|
|
|
This file is part of libgcj.
|
|
|
|
This software is copyrighted work licensed under the terms of the
|
|
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
|
|
details. */
|
|
|
|
#ifndef __SYSDEP_BACKTRACE_H__
|
|
#define __SYSDEP_BACKTRACE_H__
|
|
|
|
#include <java-stack.h>
|
|
|
|
#ifdef __CYGWIN__
|
|
/* To allow this to link as a DLL. */
|
|
#define MAIN_FUNC dll_crt0__FP11per_process
|
|
extern "C" int MAIN_FUNC () __declspec(dllimport);
|
|
#elif defined (_WIN32)
|
|
#define MAIN_FUNC DllMain
|
|
extern "C" int __stdcall MAIN_FUNC (void *, unsigned long, void *);
|
|
#else /* !__CYGWIN__ && !_WIN32 */
|
|
#define MAIN_FUNC main
|
|
extern int MAIN_FUNC (int, char **);
|
|
#endif /* ?__CYGWIN__ */
|
|
|
|
/* The context used to keep track of our position while unwinding through
|
|
the call stack. */
|
|
struct _Unwind_Context
|
|
{
|
|
/* The starting address of the method. */
|
|
_Jv_uintptr_t meth_addr;
|
|
|
|
/* The return address in the method. */
|
|
_Jv_uintptr_t ret_addr;
|
|
};
|
|
|
|
#ifdef __USING_SJLJ_EXCEPTIONS__
|
|
|
|
#undef _Unwind_GetIPInfo
|
|
#define _Unwind_GetIPInfo(ctx,ip_before_insn) \
|
|
(*(ip_before_insn) = 1, (ctx)->ret_addr)
|
|
|
|
#undef _Unwind_GetRegionStart
|
|
#define _Unwind_GetRegionStart(ctx) \
|
|
((ctx)->meth_addr)
|
|
|
|
#undef _Unwind_Backtrace
|
|
#define _Unwind_Backtrace(trace_fn,state_ptr) \
|
|
(fallback_backtrace (trace_fn, state_ptr))
|
|
|
|
#endif /* __USING_SJLJ_EXCEPTIONS__ */
|
|
|
|
/* Unwind through the call stack calling TRACE_FN with STATE for each stack
|
|
frame. Returns the reason why the unwinding was stopped. */
|
|
_Unwind_Reason_Code
|
|
fallback_backtrace (_Unwind_Trace_Fn trace_fn, _Jv_UnwindState *state)
|
|
{
|
|
register _Jv_uintptr_t *_ebp __asm__ ("ebp");
|
|
register _Jv_uintptr_t _esp __asm__ ("esp");
|
|
_Jv_uintptr_t rfp;
|
|
_Unwind_Context ctx;
|
|
|
|
for (rfp = *_ebp; rfp; rfp = *(_Jv_uintptr_t *)rfp)
|
|
{
|
|
/* Sanity checks to eliminate dubious-looking frame pointer chains.
|
|
The frame pointer should be a 32-bit word-aligned stack address.
|
|
Since the stack grows downwards on x86, the frame pointer must have
|
|
a value greater than the current value of the stack pointer, it
|
|
should not be below the supposed next frame pointer and it should
|
|
not be too far off from the supposed next frame pointer. */
|
|
int diff = *(_Jv_uintptr_t *)rfp - rfp;
|
|
if ((rfp & 0x00000003) != 0 || rfp < _esp
|
|
|| diff > 4 * 1024 || diff < 0)
|
|
break;
|
|
|
|
/* Get the return address in the calling function. This is stored on
|
|
the stack just before the value of the old frame pointer. */
|
|
ctx.ret_addr = *(_Jv_uintptr_t *)(rfp + sizeof (_Jv_uintptr_t));
|
|
|
|
/* Try to locate a "pushl %ebp; movl %esp, %ebp" function prologue
|
|
by scanning backwards at even addresses below the return address.
|
|
This instruction sequence is encoded either as 0x55 0x89 0xE5 or as
|
|
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,
|
|
but this is about the best we can do if we do not have DWARF-2 unwind
|
|
information based exception handling. */
|
|
ctx.meth_addr = (_Jv_uintptr_t)NULL;
|
|
_Jv_uintptr_t scan_addr = (ctx.ret_addr & 0xFFFFFFFE) - 2;
|
|
_Jv_uintptr_t limit_addr
|
|
= (scan_addr > 1024 * 1024) ? (scan_addr - 1024 * 1024) : 2;
|
|
for ( ; scan_addr >= limit_addr; scan_addr -= 2)
|
|
{
|
|
unsigned char *scan_bytes = (unsigned char *)scan_addr;
|
|
if (scan_bytes[0] == 0x55
|
|
&& ((scan_bytes[1] == 0x89 && scan_bytes[2] == 0xE5)
|
|
|| (scan_bytes[1] == 0x8B && scan_bytes[2] == 0xEC)))
|
|
{
|
|
ctx.meth_addr = scan_addr;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Now call the unwinder callback function. */
|
|
if (trace_fn != NULL)
|
|
(*trace_fn) (&ctx, state);
|
|
|
|
/* No need to unwind beyond _Jv_RunMain(), _Jv_ThreadStart or
|
|
main(). */
|
|
void *jv_runmain
|
|
= (void *)(void (*)(JvVMInitArgs *, jclass, const char *, int,
|
|
const char **, bool))_Jv_RunMain;
|
|
if (ctx.meth_addr == (_Jv_uintptr_t)jv_runmain
|
|
|| ctx.meth_addr == (_Jv_uintptr_t)_Jv_ThreadStart
|
|
|| (ctx.meth_addr - (_Jv_uintptr_t)MAIN_FUNC) < 16)
|
|
break;
|
|
}
|
|
|
|
return _URC_NO_REASON;
|
|
}
|
|
#endif
|