will return to. */
u = find_unwind_entry (pc);
if (u && u->stub_type != 0)
- goto restart;
+ {
+ unsigned int insn;
+
+ /* If this is a dynamic executable, and we're in a signal handler,
+ then the call chain will eventually point us into the stub for
+ _sigreturn. Unlike most cases, we'll be pointed to the branch
+ to the real sigreturn rather than the code after the real branch!.
+
+ Else, try to dig the address the stub will return to in the normal
+ fashion. */
+ insn = read_memory_integer (pc, 4);
+ if ((insn & 0xfc00e000) == 0xe8000000)
+ return (pc + extract_17 (insn) + 8) & ~0x3;
+ else
+ goto restart;
+ }
return pc;
}
int my_framesize, caller_framesize;
struct unwind_table_entry *u;
CORE_ADDR frame_base;
+ struct frame_info *tmp_frame;
/* Handle HPUX, BSD, and OSF1 style interrupt frames first. These
are easy; at *sp we have a full save state strucutre which we can
We use information from unwind descriptors to determine if %r3
is saved into the stack (Entry_GR field has this information). */
- while (frame)
+ tmp_frame = frame;
+ while (tmp_frame)
{
- u = find_unwind_entry (frame->pc);
+ u = find_unwind_entry (tmp_frame->pc);
if (!u)
{
think anyone has actually written any tools (not even "strip")
which leave them out of an executable, so maybe this is a moot
point. */
- warning ("Unable to find unwind for PC 0x%x -- Help!", frame->pc);
+ warning ("Unable to find unwind for PC 0x%x -- Help!", tmp_frame->pc);
return 0;
}
/* Entry_GR specifies the number of callee-saved general registers
saved in the stack. It starts at %r3, so %r3 would be 1. */
if (u->Entry_GR >= 1 || u->Save_SP
- || frame->signal_handler_caller
- || pc_in_interrupt_handler (frame->pc))
+ || tmp_frame->signal_handler_caller
+ || pc_in_interrupt_handler (tmp_frame->pc))
break;
else
- frame = frame->next;
+ tmp_frame = tmp_frame->next;
}
- if (frame)
+ if (tmp_frame)
{
/* We may have walked down the chain into a function with a frame
pointer. */
if (u->Save_SP
- && !frame->signal_handler_caller
- && !pc_in_interrupt_handler (frame->pc))
- return read_memory_integer (frame->frame, 4);
+ && !tmp_frame->signal_handler_caller
+ && !pc_in_interrupt_handler (tmp_frame->pc))
+ return read_memory_integer (tmp_frame->frame, 4);
/* %r3 was saved somewhere in the stack. Dig it out. */
else
{
struct frame_saved_regs saved_regs;
- get_frame_saved_regs (frame, &saved_regs);
+ /* Sick.
+
+ For optimization purposes many kernels don't have the
+ callee saved registers into the save_state structure upon
+ entry into the kernel for a syscall; the optimization
+ is usually turned off if the process is being traced so
+ that the debugger can get full register state for the
+ process.
+
+ This scheme works well except for two cases:
+
+ * Attaching to a process when the process is in the
+ kernel performing a system call (debugger can't get
+ full register state for the inferior process since
+ the process wasn't being traced when it entered the
+ system call).
+
+ * Register state is not complete if the system call
+ causes the process to core dump.
+
+
+ The following heinous code is an attempt to deal with
+ the lack of register state in a core dump. It will
+ fail miserably if the function which performs the
+ system call has a variable sized stack frame. */
+
+ get_frame_saved_regs (tmp_frame, &saved_regs);
+
+ /* Abominable hack. */
+ if (current_target.to_has_execution == 0
+ && saved_regs.regs[FLAGS_REGNUM]
+ && (read_memory_integer (saved_regs.regs[FLAGS_REGNUM], 4) & 0x2))
+ {
+ u = find_unwind_entry (FRAME_SAVED_PC (frame));
+ if (!u)
+ return read_memory_integer (saved_regs.regs[FP_REGNUM], 4);
+ else
+ return frame_base - (u->Total_frame_size << 3);
+ }
+
return read_memory_integer (saved_regs.regs[FP_REGNUM], 4);
}
}