(ia64_local_resume): Begin to support unw_resume() that goes across a signal

(not complete yet).

(Logical change 1.40)

src/ia64/Gresume-ia64.c

@@ -1,5 +1,5 @@
 /* libunwind - a platform-independent unwind library
-   Copyright (C) 2001-2002 Hewlett-Packard Co
+   Copyright (C) 2001-2003 Hewlett-Packard Co
 	Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
 
 This file is part of libunwind.
@@ -27,6 +27,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
 
 #include "rse.h"
 #include "unwind_i.h"
+#include "offsets.h"
 
 #ifndef UNW_REMOTE_ONLY
 
@@ -34,6 +35,7 @@ HIDDEN inline int
 ia64_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
 {
   struct cursor *c = (struct cursor *) cursor;
+  long do_sigreturn = 0;
   unw_fpreg_t fpval;
   ucontext_t *uc = arg;
   unw_word_t val, sol;
@@ -97,20 +99,52 @@ ia64_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
   for (i = 16; i < 32; ++i)
     SET_FPREG (sc_fr[i], fr_loc[i - 16]);
 
-  if (c->is_signal_frame)
-    abort ();	/* XXX this needs to be fixed... */
-
-  /* Account for the fact that __ia64_install_context() returns via
-     br.ret, which will decrement bsp by size-of-locals.  */
-  sol = (uc->uc_mcontext.sc_ar_pfs >> 7) & 0x7f;
-  uc->uc_mcontext.sc_ar_bsp = ia64_rse_skip_regs (c->bsp, sol);
-
   uc->uc_mcontext.sc_flags = 0;
   uc->uc_mcontext.sc_gr[1] = c->pi.gp;
   uc->uc_mcontext.sc_gr[12] = c->psp;
 
+  if (unlikely (c->sigcontext_loc))
+    {
+      struct sigcontext *sc = (struct sigcontext *) c->sigcontext_loc;
+
+      /* We're returning to a frame that was (either directly or
+	 indirectly) interrupted by a signal.  We have to restore
+	 _both_ "preserved" and "scratch" registers.  That doesn't
+	 leave us any registers to work with, and the only way we can
+	 achieve this is by doing a sigreturn().
+
+	 Note: it might be tempting to think that we don't have to
+	 restore the scratch registers when returning to a frame that
+	 was indirectly interrupted by a signal.  However, that is not
+	 safe because that frame and its descendants could have been
+	 using a special convention that stores "preserved" state in
+	 scratch registers.  The fsyscall convention does this with
+	 r11 (to save ar.pfs) and b6 (to save "rp"), for example. */
+      sc->sc_ip = uc->uc_mcontext.sc_br[0];
+      sc->sc_gr[12] = c->psp;
+      uc->uc_mcontext.sc_gr[12] = (c->sigcontext_loc - c->sigcontext_off);
+      do_sigreturn = 1;
+
+      /* Account for the fact that sigreturn will decrement bsp by
+	 size-of-frame.  */
+#if 0
+      sof = (uc->uc_mcontext.sc_ar_pfs >> 0) & 0x7f;
+      uc->uc_mcontext.sc_ar_bsp = ia64_rse_skip_regs (c->bsp, sof);
+#else
+      uc->uc_mcontext.sc_ar_bsp = sc->sc_ar_bsp;
+#endif
+printf("uc->bsp=%p, sc->bsp=%p\n", uc->uc_mcontext.sc_ar_bsp, sc->sc_ar_bsp);
+    }
+  else
+    {
+      /* Account for the fact that __ia64_install_context() returns
+	 via br.ret, which will decrement bsp by size-of-locals.  */
+      sol = (uc->uc_mcontext.sc_ar_pfs >> 7) & 0x7f;
+printf("this needs fixing\n");
+      uc->uc_mcontext.sc_ar_bsp = ia64_rse_skip_regs (c->bsp, sol);
+    }
   __ia64_install_context (uc, c->eh_args[0], c->eh_args[1], c->eh_args[2],
-			  c->eh_args[3]);
+			  c->eh_args[3], do_sigreturn);
 }
 
 #endif /* !UNW_REMOTE_ONLY */