From 3ed09a32677624b5eb98dfe31a4f3b249eaa6dc5 Mon Sep 17 00:00:00 2001
From: Daniel Jacobowitz <drow@false.org>
Date: Sun, 7 Nov 2004 21:16:11 +0000
Subject: [PATCH] 	* dwarf2-frame.c (struct dwarf2_frame_ops): Add
 signal_frame_p. 	(dwarf2_frame_set_signal_frame_p,
 dwarf2_frame_signal_frame_p) 	(dwarf2_signal_frame_unwind): New. 
 (dwarf2_frame_sniffer): Use dwarf2_frame_signal_frame_p. 	*
 dwarf2-frame.h (dwarf2_frame_set_signal_frame_p): New prototype.

---
 gdb/ChangeLog      |  8 +++++++
 gdb/dwarf2-frame.c | 52 +++++++++++++++++++++++++++++++++++++++++++---
 gdb/dwarf2-frame.h |  8 +++++++
 3 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4a9b4e3913..2b171379c8 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2004-11-07  Daniel Jacobowitz  <dan@debian.org>
+
+	* dwarf2-frame.c (struct dwarf2_frame_ops): Add signal_frame_p.
+	(dwarf2_frame_set_signal_frame_p, dwarf2_frame_signal_frame_p)
+	(dwarf2_signal_frame_unwind): New.
+	(dwarf2_frame_sniffer): Use dwarf2_frame_signal_frame_p.
+	* dwarf2-frame.h (dwarf2_frame_set_signal_frame_p): New prototype.
+
 2004-11-07  Mark Kettenis  <kettenis@gnu.org>
 
 	* Makefile.in (mips64obsd-tdep.o): Fix typo.
diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c
index 4bad147ffd..6a37e5df7d 100644
--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -471,6 +471,10 @@ struct dwarf2_frame_ops
 {
   /* Pre-initialize the register state REG for register REGNUM.  */
   void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *);
+
+  /* Check whether the frame preceding NEXT_FRAME will be a signal
+     trampoline.  */
+  int (*signal_frame_p) (struct gdbarch *, struct frame_info *);
 };
 
 /* Default architecture-specific register state initialization
@@ -547,6 +551,33 @@ dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
 
   ops->init_reg (gdbarch, regnum, reg);
 }
+
+/* Set the architecture-specific signal trampoline recognition
+   function for GDBARCH to SIGNAL_FRAME_P.  */
+
+void
+dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
+				 int (*signal_frame_p) (struct gdbarch *,
+							struct frame_info *))
+{
+  struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
+
+  ops->signal_frame_p = signal_frame_p;
+}
+
+/* Query the architecture-specific signal frame recognizer for
+   NEXT_FRAME.  */
+
+static int
+dwarf2_frame_signal_frame_p (struct gdbarch *gdbarch,
+			     struct frame_info *next_frame)
+{
+  struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
+
+  if (ops->signal_frame_p == NULL)
+    return 0;
+  return ops->signal_frame_p (gdbarch, next_frame);
+}
 
 
 struct dwarf2_frame_cache
@@ -845,6 +876,13 @@ static const struct frame_unwind dwarf2_frame_unwind =
   dwarf2_frame_prev_register
 };
 
+static const struct frame_unwind dwarf2_signal_frame_unwind =
+{
+  SIGTRAMP_FRAME,
+  dwarf2_frame_this_id,
+  dwarf2_frame_prev_register
+};
+
 const struct frame_unwind *
 dwarf2_frame_sniffer (struct frame_info *next_frame)
 {
@@ -852,10 +890,18 @@ dwarf2_frame_sniffer (struct frame_info *next_frame)
      function.  frame_pc_unwind(), for a no-return next function, can
      end up returning something past the end of this function's body.  */
   CORE_ADDR block_addr = frame_unwind_address_in_block (next_frame);
-  if (dwarf2_frame_find_fde (&block_addr))
-    return &dwarf2_frame_unwind;
+  if (!dwarf2_frame_find_fde (&block_addr))
+    return NULL;
 
-  return NULL;
+  /* On some targets, signal trampolines may have unwind information.
+     We need to recognize them so that we set the frame type
+     correctly.  */
+
+  if (dwarf2_frame_signal_frame_p (get_frame_arch (next_frame),
+				   next_frame))
+    return &dwarf2_signal_frame_unwind;
+
+  return &dwarf2_frame_unwind;
 }
 
 
diff --git a/gdb/dwarf2-frame.h b/gdb/dwarf2-frame.h
index 1ae44b5064..5191c0e8d4 100644
--- a/gdb/dwarf2-frame.h
+++ b/gdb/dwarf2-frame.h
@@ -79,6 +79,14 @@ extern void dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
 				       void (*init_reg) (struct gdbarch *, int,
 					     struct dwarf2_frame_state_reg *));
 
+/* Set the architecture-specific signal trampoline recognition
+   function for GDBARCH to SIGNAL_FRAME_P.  */
+
+extern void
+  dwarf2_frame_set_signal_frame_p (struct gdbarch *gdbarch,
+				   int (*signal_frame_p) (struct gdbarch *,
+							  struct frame_info *));
+
 /* Return the frame unwind methods for the function that contains PC,
    or NULL if it can't be handled by DWARF CFI frame unwinder.  */
 
-- 
2.34.1