X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gdb%2Fframe.c;h=dfd6b3d53c85c895f0e4e78d6fba670a682b8e25;hb=2c0b251b29eeafa90c84a3a938c744bc7ba81aea;hp=560fcdea38f35d75b22823509b60a5f30bae89dd;hpb=3e8c568d4fc67da218a87d51da180bba5ad585f1;p=deliverable%2Fbinutils-gdb.git

diff --git a/gdb/frame.c b/gdb/frame.c
index 560fcdea38..dfd6b3d53c 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -1,13 +1,13 @@
 /* Cache and manage frames for GDB, the GNU debugger.
 
    Copyright (C) 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, 2001,
-   2002, 2003, 2004, 2007 Free Software Foundation, Inc.
+   2002, 2003, 2004, 2007, 2008, 2009 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2 of the License, or
+   the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
@@ -16,9 +16,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 51 Franklin Street, Fifth Floor,
-   Boston, MA 02110-1301, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
 #include "frame.h"
@@ -42,6 +40,7 @@
 #include "observer.h"
 #include "objfiles.h"
 #include "exceptions.h"
+#include "gdbthread.h"
 
 static struct frame_info *get_prev_frame_1 (struct frame_info *this_frame);
 
@@ -115,7 +114,7 @@ struct frame_info
 
 /* Flag to control debugging.  */
 
-static int frame_debug;
+int frame_debug;
 static void
 show_frame_debug (struct ui_file *file, int from_tty,
 		  struct cmd_list_element *c, const char *value)
@@ -257,10 +256,9 @@ get_frame_id (struct frame_info *fi)
 			    fi->level);
       /* Find the unwinder.  */
       if (fi->unwind == NULL)
-	fi->unwind = frame_unwind_find_by_frame (fi->next,
-						 &fi->prologue_cache);
+	fi->unwind = frame_unwind_find_by_frame (fi, &fi->prologue_cache);
       /* Find THIS frame's ID.  */
-      fi->unwind->this_id (fi->next, &fi->prologue_cache, &fi->this_id.value);
+      fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value);
       fi->this_id.p = 1;
       if (frame_debug)
 	{
@@ -370,8 +368,34 @@ frame_id_eq (struct frame_id l, struct frame_id r)
   return eq;
 }
 
-int
-frame_id_inner (struct frame_id l, struct frame_id r)
+/* Safety net to check whether frame ID L should be inner to
+   frame ID R, according to their stack addresses.
+
+   This method cannot be used to compare arbitrary frames, as the
+   ranges of valid stack addresses may be discontiguous (e.g. due
+   to sigaltstack).
+
+   However, it can be used as safety net to discover invalid frame
+   IDs in certain circumstances.
+
+   * If frame NEXT is the immediate inner frame to THIS, and NEXT
+     is a NORMAL frame, then the stack address of NEXT must be
+     inner-than-or-equal to the stack address of THIS.
+
+     Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind
+     error has occurred.
+
+   * If frame NEXT is the immediate inner frame to THIS, and NEXT
+     is a NORMAL frame, and NEXT and THIS have different stack
+     addresses, no other frame in the frame chain may have a stack
+     address in between.
+
+     Therefore, if frame_id_inner (TEST, THIS) holds, but
+     frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer
+     to a valid frame in the frame chain.   */
+
+static int
+frame_id_inner (struct gdbarch *gdbarch, struct frame_id l, struct frame_id r)
 {
   int inner;
   if (!l.stack_addr_p || !r.stack_addr_p)
@@ -382,7 +406,7 @@ frame_id_inner (struct frame_id l, struct frame_id r)
        comment in "frame.h", there is some fuzz here.  Frameless
        functions are not strictly inner than (same .stack but
        different .code and/or .special address).  */
-    inner = gdbarch_inner_than (current_gdbarch, l.stack_addr, r.stack_addr);
+    inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr);
   if (frame_debug)
     {
       fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l=");
@@ -397,28 +421,34 @@ frame_id_inner (struct frame_id l, struct frame_id r)
 struct frame_info *
 frame_find_by_id (struct frame_id id)
 {
-  struct frame_info *frame;
+  struct frame_info *frame, *prev_frame;
 
   /* ZERO denotes the null frame, let the caller decide what to do
      about it.  Should it instead return get_current_frame()?  */
   if (!frame_id_p (id))
     return NULL;
 
-  for (frame = get_current_frame ();
-       frame != NULL;
-       frame = get_prev_frame (frame))
+  for (frame = get_current_frame (); ; frame = prev_frame)
     {
       struct frame_id this = get_frame_id (frame);
       if (frame_id_eq (id, this))
 	/* An exact match.  */
 	return frame;
-      if (frame_id_inner (id, this))
-	/* Gone to far.  */
+
+      prev_frame = get_prev_frame (frame);
+      if (!prev_frame)
+	return NULL;
+
+      /* As a safety net to avoid unnecessary backtracing while trying
+	 to find an invalid ID, we check for a common situation where
+	 we can detect from comparing stack addresses that no other
+	 frame in the current frame chain can have this ID.  See the
+	 comment at frame_id_inner for details.   */
+      if (get_frame_type (frame) == NORMAL_FRAME
+	  && !frame_id_inner (get_frame_arch (frame), id, this)
+	  && frame_id_inner (get_frame_arch (prev_frame), id,
+			     get_frame_id (prev_frame)))
 	return NULL;
-      /* Either we're not yet gone far enough out along the frame
-         chain (inner(this,id)), or we're comparing frameless functions
-         (same .base, different .func, no test available).  Struggle
-         on until we've definitly gone to far.  */
     }
   return NULL;
 }
@@ -429,15 +459,7 @@ frame_pc_unwind (struct frame_info *this_frame)
   if (!this_frame->prev_pc.p)
     {
       CORE_ADDR pc;
-      if (this_frame->unwind == NULL)
-	this_frame->unwind
-	  = frame_unwind_find_by_frame (this_frame->next,
-					&this_frame->prologue_cache);
-      if (this_frame->unwind->prev_pc != NULL)
-	/* A per-frame unwinder, prefer it.  */
-	pc = this_frame->unwind->prev_pc (this_frame->next,
-					  &this_frame->prologue_cache);
-      else if (gdbarch_unwind_pc_p (current_gdbarch))
+      if (gdbarch_unwind_pc_p (get_frame_arch (this_frame)))
 	{
 	  /* The right way.  The `pure' way.  The one true way.  This
 	     method depends solely on the register-unwind code to
@@ -455,7 +477,7 @@ frame_pc_unwind (struct frame_info *this_frame)
 	     frame.  This is all in stark contrast to the old
 	     FRAME_SAVED_PC which would try to directly handle all the
 	     different ways that a PC could be unwound.  */
-	  pc = gdbarch_unwind_pc (current_gdbarch, this_frame);
+	  pc = gdbarch_unwind_pc (get_frame_arch (this_frame), this_frame);
 	}
       else
 	internal_error (__FILE__, __LINE__, _("No unwind_pc method"));
@@ -471,40 +493,36 @@ frame_pc_unwind (struct frame_info *this_frame)
 }
 
 CORE_ADDR
-frame_func_unwind (struct frame_info *fi, enum frame_type this_type)
+get_frame_func (struct frame_info *this_frame)
 {
-  if (!fi->prev_func.p)
+  struct frame_info *next_frame = this_frame->next;
+
+  if (!next_frame->prev_func.p)
     {
       /* Make certain that this, and not the adjacent, function is
          found.  */
-      CORE_ADDR addr_in_block = frame_unwind_address_in_block (fi, this_type);
-      fi->prev_func.p = 1;
-      fi->prev_func.addr = get_pc_function_start (addr_in_block);
+      CORE_ADDR addr_in_block = get_frame_address_in_block (this_frame);
+      next_frame->prev_func.p = 1;
+      next_frame->prev_func.addr = get_pc_function_start (addr_in_block);
       if (frame_debug)
 	fprintf_unfiltered (gdb_stdlog,
-			    "{ frame_func_unwind (fi=%d) -> 0x%s }\n",
-			    fi->level, paddr_nz (fi->prev_func.addr));
+			    "{ get_frame_func (this_frame=%d) -> 0x%s }\n",
+			    this_frame->level,
+			    paddr_nz (next_frame->prev_func.addr));
     }
-  return fi->prev_func.addr;
-}
-
-CORE_ADDR
-get_frame_func (struct frame_info *fi)
-{
-  return frame_func_unwind (fi->next, get_frame_type (fi));
+  return next_frame->prev_func.addr;
 }
 
 static int
 do_frame_register_read (void *src, int regnum, gdb_byte *buf)
 {
-  frame_register_read (src, regnum, buf);
-  return 1;
+  return frame_register_read (src, regnum, buf);
 }
 
 struct regcache *
 frame_save_as_regcache (struct frame_info *this_frame)
 {
-  struct regcache *regcache = regcache_xmalloc (current_gdbarch);
+  struct regcache *regcache = regcache_xmalloc (get_frame_arch (this_frame));
   struct cleanup *cleanups = make_cleanup_regcache_xfree (regcache);
   regcache_save (regcache, do_frame_register_read, this_frame);
   discard_cleanups (cleanups);
@@ -518,6 +536,14 @@ frame_pop (struct frame_info *this_frame)
   struct regcache *scratch;
   struct cleanup *cleanups;
 
+  if (get_frame_type (this_frame) == DUMMY_FRAME)
+    {
+      /* Popping a dummy frame involves restoring more than just registers.
+	 dummy_frame_pop does all the work.  */
+      dummy_frame_pop (get_frame_id (this_frame));
+      return;
+    }
+
   /* Ensure that we have a frame to pop to.  */
   prev_frame = get_prev_frame_1 (this_frame);
 
@@ -554,15 +580,7 @@ frame_register_unwind (struct frame_info *frame, int regnum,
 		       int *optimizedp, enum lval_type *lvalp,
 		       CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp)
 {
-  struct frame_unwind_cache *cache;
-
-  if (frame_debug)
-    {
-      fprintf_unfiltered (gdb_stdlog, "\
-{ frame_register_unwind (frame=%d,regnum=%d(%s),...) ",
-			  frame->level, regnum,
-			  frame_map_regnum_to_name (frame, regnum));
-    }
+  struct value *value;
 
   /* Require all but BUFFERP to be valid.  A NULL BUFFERP indicates
      that the value proper does not need to be fetched.  */
@@ -572,43 +590,23 @@ frame_register_unwind (struct frame_info *frame, int regnum,
   gdb_assert (realnump != NULL);
   /* gdb_assert (bufferp != NULL); */
 
-  /* NOTE: cagney/2002-11-27: A program trying to unwind a NULL frame
-     is broken.  There is always a frame.  If there, for some reason,
-     isn't a frame, there is some pretty busted code as it should have
-     detected the problem before calling here.  */
-  gdb_assert (frame != NULL);
+  value = frame_unwind_register_value (frame, regnum);
 
-  /* Find the unwinder.  */
-  if (frame->unwind == NULL)
-    frame->unwind = frame_unwind_find_by_frame (frame->next,
-						&frame->prologue_cache);
+  gdb_assert (value != NULL);
 
-  /* Ask this frame to unwind its register.  See comment in
-     "frame-unwind.h" for why NEXT frame and this unwind cache are
-     passed in.  */
-  frame->unwind->prev_register (frame->next, &frame->prologue_cache, regnum,
-				optimizedp, lvalp, addrp, realnump, bufferp);
+  *optimizedp = value_optimized_out (value);
+  *lvalp = VALUE_LVAL (value);
+  *addrp = VALUE_ADDRESS (value);
+  *realnump = VALUE_REGNUM (value);
 
-  if (frame_debug)
-    {
-      fprintf_unfiltered (gdb_stdlog, "->");
-      fprintf_unfiltered (gdb_stdlog, " *optimizedp=%d", (*optimizedp));
-      fprintf_unfiltered (gdb_stdlog, " *lvalp=%d", (int) (*lvalp));
-      fprintf_unfiltered (gdb_stdlog, " *addrp=0x%s", paddr_nz ((*addrp)));
-      fprintf_unfiltered (gdb_stdlog, " *bufferp=");
-      if (bufferp == NULL)
-	fprintf_unfiltered (gdb_stdlog, "<NULL>");
-      else
-	{
-	  int i;
-	  const unsigned char *buf = bufferp;
-	  fprintf_unfiltered (gdb_stdlog, "[");
-	  for (i = 0; i < register_size (current_gdbarch, regnum); i++)
-	    fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
-	  fprintf_unfiltered (gdb_stdlog, "]");
-	}
-      fprintf_unfiltered (gdb_stdlog, " }\n");
-    }
+  if (bufferp)
+    memcpy (bufferp, value_contents_all (value),
+	    TYPE_LENGTH (value_type (value)));
+
+  /* Dispose of the new value.  This prevents watchpoints from
+     trying to watch the saved frame pointer.  */
+  release_value (value);
+  value_free (value);
 }
 
 void
@@ -649,6 +647,72 @@ get_frame_register (struct frame_info *frame,
   frame_unwind_register (frame->next, regnum, buf);
 }
 
+struct value *
+frame_unwind_register_value (struct frame_info *frame, int regnum)
+{
+  struct value *value;
+
+  gdb_assert (frame != NULL);
+
+  if (frame_debug)
+    {
+      fprintf_unfiltered (gdb_stdlog, "\
+{ frame_unwind_register_value (frame=%d,regnum=%d(%s),...) ",
+			  frame->level, regnum,
+			  user_reg_map_regnum_to_name
+			    (get_frame_arch (frame), regnum));
+    }
+
+  /* Find the unwinder.  */
+  if (frame->unwind == NULL)
+    frame->unwind = frame_unwind_find_by_frame (frame, &frame->prologue_cache);
+
+  /* Ask this frame to unwind its register.  */
+  value = frame->unwind->prev_register (frame, &frame->prologue_cache, regnum);
+
+  if (frame_debug)
+    {
+      fprintf_unfiltered (gdb_stdlog, "->");
+      if (value_optimized_out (value))
+	fprintf_unfiltered (gdb_stdlog, " optimized out");
+      else
+	{
+	  if (VALUE_LVAL (value) == lval_register)
+	    fprintf_unfiltered (gdb_stdlog, " register=%d",
+				VALUE_REGNUM (value));
+	  else if (VALUE_LVAL (value) == lval_memory)
+	    fprintf_unfiltered (gdb_stdlog, " address=0x%s",
+				paddr_nz (VALUE_ADDRESS (value)));
+	  else
+	    fprintf_unfiltered (gdb_stdlog, " computed");
+
+	  if (value_lazy (value))
+	    fprintf_unfiltered (gdb_stdlog, " lazy");
+	  else
+	    {
+	      int i;
+	      const gdb_byte *buf = value_contents (value);
+
+	      fprintf_unfiltered (gdb_stdlog, " bytes=");
+	      fprintf_unfiltered (gdb_stdlog, "[");
+	      for (i = 0; i < register_size (get_frame_arch (frame), regnum); i++)
+		fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
+	      fprintf_unfiltered (gdb_stdlog, "]");
+	    }
+	}
+
+      fprintf_unfiltered (gdb_stdlog, " }\n");
+    }
+
+  return value;
+}
+
+struct value *
+get_frame_register_value (struct frame_info *frame, int regnum)
+{
+  return frame_unwind_register_value (frame->next, regnum);
+}
+
 LONGEST
 frame_unwind_register_signed (struct frame_info *frame, int regnum)
 {
@@ -679,17 +743,6 @@ get_frame_register_unsigned (struct frame_info *frame, int regnum)
   return frame_unwind_register_unsigned (frame->next, regnum);
 }
 
-void
-frame_unwind_unsigned_register (struct frame_info *frame, int regnum,
-				ULONGEST *val)
-{
-  gdb_byte buf[MAX_REGISTER_SIZE];
-  frame_unwind_register (frame, regnum, buf);
-  (*val) = extract_unsigned_integer (buf,
-				     register_size (get_frame_arch (frame),
-						    regnum));
-}
-
 void
 put_frame_register (struct frame_info *frame, int regnum,
 		    const gdb_byte *buf)
@@ -746,6 +799,9 @@ get_frame_register_bytes (struct frame_info *frame, int regnum,
 			  CORE_ADDR offset, int len, gdb_byte *myaddr)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
+  int i;
+  int maxsize;
+  int numregs;
 
   /* Skip registers wholly inside of OFFSET.  */
   while (offset >= register_size (gdbarch, regnum))
@@ -754,6 +810,24 @@ get_frame_register_bytes (struct frame_info *frame, int regnum,
       regnum++;
     }
 
+  /* Ensure that we will not read beyond the end of the register file.
+     This can only ever happen if the debug information is bad.  */
+  maxsize = -offset;
+  numregs = gdbarch_num_regs (gdbarch) + gdbarch_num_pseudo_regs (gdbarch);
+  for (i = regnum; i < numregs; i++)
+    {
+      int thissize = register_size (gdbarch, i);
+      if (thissize == 0)
+	break;	/* This register is not available on this architecture.  */
+      maxsize += thissize;
+    }
+  if (len > maxsize)
+    {
+      warning (_("Bad debug information detected: "
+		 "Attempt to read %d bytes from registers."), len);
+      return 0;
+    }
+
   /* Copy the data.  */
   while (len > 0)
     {
@@ -822,22 +896,6 @@ put_frame_register_bytes (struct frame_info *frame, int regnum,
     }
 }
 
-/* Map between a frame register number and its name.  A frame register
-   space is a superset of the cooked register space --- it also
-   includes builtin registers.  */
-
-int
-frame_map_name_to_regnum (struct frame_info *frame, const char *name, int len)
-{
-  return user_reg_map_name_to_regnum (get_frame_arch (frame), name, len);
-}
-
-const char *
-frame_map_regnum_to_name (struct frame_info *frame, int regnum)
-{
-  return user_reg_map_regnum_to_name (get_frame_arch (frame), regnum);
-}
-
 /* Create a sentinel frame.  */
 
 static struct frame_info *
@@ -916,6 +974,9 @@ get_current_frame (void)
     error (_("No stack."));
   if (!target_has_memory)
     error (_("No memory."));
+  if (is_executing (inferior_ptid))
+    error (_("Target is executing."));
+
   if (current_frame == NULL)
     {
       struct frame_info *sentinel_frame =
@@ -936,6 +997,20 @@ get_current_frame (void)
 
 static struct frame_info *selected_frame;
 
+int
+has_stack_frames (void)
+{
+  if (!target_has_registers || !target_has_stack || !target_has_memory)
+    return 0;
+
+  /* If the current thread is executing, don't try to read from
+     it.  */
+  if (is_executing (inferior_ptid))
+    return 0;
+
+  return 1;
+}
+
 /* Return the selected frame.  Always non-NULL (unless there isn't an
    inferior sufficient for creating a frame) in which case an error is
    thrown.  */
@@ -945,9 +1020,7 @@ get_selected_frame (const char *message)
 {
   if (selected_frame == NULL)
     {
-      if (message != NULL && (!target_has_registers
-			      || !target_has_stack
-			      || !target_has_memory))
+      if (message != NULL && !has_stack_frames ())
 	error (("%s"), message);
       /* Hey!  Don't trust this.  It should really be re-finding the
 	 last selected frame of the currently selected thread.  This,
@@ -966,7 +1039,7 @@ get_selected_frame (const char *message)
 struct frame_info *
 deprecated_safe_get_selected_frame (void)
 {
-  if (!target_has_registers || !target_has_stack || !target_has_memory)
+  if (!has_stack_frames ())
     return NULL;
   return get_selected_frame (NULL);
 }
@@ -1033,13 +1106,19 @@ create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
 
   fi->next = create_sentinel_frame (get_current_regcache ());
 
+  /* Set/update this frame's cached PC value, found in the next frame.
+     Do this before looking for this frame's unwinder.  A sniffer is
+     very likely to read this, and the corresponding unwinder is
+     entitled to rely that the PC doesn't magically change.  */
+  fi->next->prev_pc.value = pc;
+  fi->next->prev_pc.p = 1;
+
   /* Select/initialize both the unwind function and the frame's type
      based on the PC.  */
-  fi->unwind = frame_unwind_find_by_frame (fi->next, &fi->prologue_cache);
+  fi->unwind = frame_unwind_find_by_frame (fi, &fi->prologue_cache);
 
   fi->this_id.p = 1;
-  deprecated_update_frame_base_hack (fi, addr);
-  deprecated_update_frame_pc_hack (fi, pc);
+  fi->this_id.value = frame_id_build (addr, pc);
 
   if (frame_debug)
     {
@@ -1066,7 +1145,7 @@ get_next_frame (struct frame_info *this_frame)
 
 /* Observer for the target_changed event.  */
 
-void
+static void
 frame_observer_target_changed (struct target_ops *target)
 {
   reinit_frame_cache ();
@@ -1092,9 +1171,11 @@ reinit_frame_cache (void)
   obstack_free (&frame_cache_obstack, 0);
   obstack_init (&frame_cache_obstack);
 
+  if (current_frame != NULL)
+    annotate_frames_invalid ();
+
   current_frame = NULL;		/* Invalidate cache */
   select_frame (NULL);
-  annotate_frames_invalid ();
   if (frame_debug)
     fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n");
 }
@@ -1137,8 +1218,10 @@ get_prev_frame_1 (struct frame_info *this_frame)
 {
   struct frame_info *prev_frame;
   struct frame_id this_id;
+  struct gdbarch *gdbarch;
 
   gdb_assert (this_frame != NULL);
+  gdbarch = get_frame_arch (this_frame);
 
   if (frame_debug)
     {
@@ -1161,6 +1244,15 @@ get_prev_frame_1 (struct frame_info *this_frame)
 	}
       return this_frame->prev;
     }
+
+  /* If the frame unwinder hasn't been selected yet, we must do so
+     before setting prev_p; otherwise the check for misbehaved
+     sniffers will think that this frame's sniffer tried to unwind
+     further (see frame_cleanup_after_sniffer).  */
+  if (this_frame->unwind == NULL)
+    this_frame->unwind
+      = frame_unwind_find_by_frame (this_frame, &this_frame->prologue_cache);
+
   this_frame->prev_p = 1;
   this_frame->stop_reason = UNWIND_NO_REASON;
 
@@ -1182,11 +1274,11 @@ get_prev_frame_1 (struct frame_info *this_frame)
 
   /* Check that this frame's ID isn't inner to (younger, below, next)
      the next frame.  This happens when a frame unwind goes backwards.
-     Exclude signal trampolines (due to sigaltstack the frame ID can
-     go backwards) and sentinel frames (the test is meaningless).  */
-  if (this_frame->next->level >= 0
-      && this_frame->next->unwind->type != SIGTRAMP_FRAME
-      && frame_id_inner (this_id, get_frame_id (this_frame->next)))
+     This check is valid only if the next frame is NORMAL.  See the
+     comment at frame_id_inner for details.  */
+  if (this_frame->next->unwind->type == NORMAL_FRAME
+      && frame_id_inner (get_frame_arch (this_frame->next), this_id,
+			 get_frame_id (this_frame->next)))
     {
       if (frame_debug)
 	{
@@ -1229,22 +1321,23 @@ get_prev_frame_1 (struct frame_info *this_frame)
      method set the same lval and location information as
      frame_register_unwind.  */
   if (this_frame->level > 0
-      && gdbarch_pc_regnum (current_gdbarch) >= 0
+      && gdbarch_pc_regnum (gdbarch) >= 0
       && get_frame_type (this_frame) == NORMAL_FRAME
       && get_frame_type (this_frame->next) == NORMAL_FRAME)
     {
-      int optimized, realnum;
+      int optimized, realnum, nrealnum;
       enum lval_type lval, nlval;
       CORE_ADDR addr, naddr;
 
       frame_register_unwind_location (this_frame,
-				      gdbarch_pc_regnum (current_gdbarch),
+				      gdbarch_pc_regnum (gdbarch),
 				      &optimized, &lval, &addr, &realnum);
       frame_register_unwind_location (get_next_frame (this_frame),
-				      gdbarch_pc_regnum (current_gdbarch),
-				      &optimized, &nlval, &naddr, &realnum);
+				      gdbarch_pc_regnum (gdbarch),
+				      &optimized, &nlval, &naddr, &nrealnum);
 
-      if (lval == lval_memory && lval == nlval && addr == naddr)
+      if ((lval == lval_memory && lval == nlval && addr == naddr)
+	  || (lval == lval_register && lval == nlval && realnum == nrealnum))
 	{
 	  if (frame_debug)
 	    {
@@ -1308,8 +1401,7 @@ get_prev_frame_1 (struct frame_info *this_frame)
 /* Debug routine to print a NULL frame being returned.  */
 
 static void
-frame_debug_got_null_frame (struct ui_file *file,
-			    struct frame_info *this_frame,
+frame_debug_got_null_frame (struct frame_info *this_frame,
 			    const char *reason)
 {
   if (frame_debug)
@@ -1338,7 +1430,7 @@ inside_main_func (struct frame_info *this_frame)
     return 0;
   /* Make certain that the code, and not descriptor, address is
      returned.  */
-  maddr = gdbarch_convert_from_func_ptr_addr (current_gdbarch,
+  maddr = gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame),
 					      SYMBOL_VALUE_ADDRESS (msymbol),
 					      &current_target);
   return maddr == get_frame_func (this_frame);
@@ -1366,42 +1458,6 @@ get_prev_frame (struct frame_info *this_frame)
 {
   struct frame_info *prev_frame;
 
-  /* Return the inner-most frame, when the caller passes in NULL.  */
-  /* NOTE: cagney/2002-11-09: Not sure how this would happen.  The
-     caller should have previously obtained a valid frame using
-     get_selected_frame() and then called this code - only possibility
-     I can think of is code behaving badly.
-
-     NOTE: cagney/2003-01-10: Talk about code behaving badly.  Check
-     block_innermost_frame().  It does the sequence: frame = NULL;
-     while (1) { frame = get_prev_frame (frame); .... }.  Ulgh!  Why
-     it couldn't be written better, I don't know.
-
-     NOTE: cagney/2003-01-11: I suspect what is happening in
-     block_innermost_frame() is, when the target has no state
-     (registers, memory, ...), it is still calling this function.  The
-     assumption being that this function will return NULL indicating
-     that a frame isn't possible, rather than checking that the target
-     has state and then calling get_current_frame() and
-     get_prev_frame().  This is a guess mind.  */
-  if (this_frame == NULL)
-    {
-      /* NOTE: cagney/2002-11-09: There was a code segment here that
-	 would error out when CURRENT_FRAME was NULL.  The comment
-	 that went with it made the claim ...
-
-	 ``This screws value_of_variable, which just wants a nice
-	 clean NULL return from block_innermost_frame if there are no
-	 frames.  I don't think I've ever seen this message happen
-	 otherwise.  And returning NULL here is a perfectly legitimate
-	 thing to do.''
-
-         Per the above, this code shouldn't even be called with a NULL
-         THIS_FRAME.  */
-      frame_debug_got_null_frame (gdb_stdlog, this_frame, "this_frame NULL");
-      return current_frame;
-    }
-
   /* There is always a frame.  If this assertion fails, suspect that
      something should be calling get_selected_frame() or
      get_current_frame().  */
@@ -1426,7 +1482,7 @@ get_prev_frame (struct frame_info *this_frame)
        user later decides to enable unwinds past main(), that will
        automatically happen.  */
     {
-      frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside main func");
+      frame_debug_got_null_frame (this_frame, "inside main func");
       return NULL;
     }
 
@@ -1437,8 +1493,7 @@ get_prev_frame (struct frame_info *this_frame)
      frame.  */
   if (this_frame->level + 2 > backtrace_limit)
     {
-      frame_debug_got_null_frame (gdb_stdlog, this_frame,
-				  "backtrace limit exceeded");
+      frame_debug_got_null_frame (this_frame, "backtrace limit exceeded");
       return NULL;
     }
 
@@ -1468,7 +1523,7 @@ get_prev_frame (struct frame_info *this_frame)
       && get_frame_type (this_frame) != DUMMY_FRAME && this_frame->level >= 0
       && inside_entry_func (this_frame))
     {
-      frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside entry func");
+      frame_debug_got_null_frame (this_frame, "inside entry func");
       return NULL;
     }
 
@@ -1480,7 +1535,7 @@ get_prev_frame (struct frame_info *this_frame)
       && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME
       && get_frame_pc (this_frame) == 0)
     {
-      frame_debug_got_null_frame (gdb_stdlog, this_frame, "zero PC");
+      frame_debug_got_null_frame (this_frame, "zero PC");
       return NULL;
     }
 
@@ -1494,43 +1549,54 @@ get_frame_pc (struct frame_info *frame)
   return frame_pc_unwind (frame->next);
 }
 
-/* Return an address that falls within NEXT_FRAME's caller's code
-   block, assuming that the caller is a THIS_TYPE frame.  */
+/* Return an address that falls within THIS_FRAME's code block.  */
 
 CORE_ADDR
-frame_unwind_address_in_block (struct frame_info *next_frame,
-			       enum frame_type this_type)
+get_frame_address_in_block (struct frame_info *this_frame)
 {
   /* A draft address.  */
-  CORE_ADDR pc = frame_pc_unwind (next_frame);
-
-  /* If NEXT_FRAME was called by a signal frame or dummy frame, then
-     we shold not adjust the unwound PC.  These frames may not call
-     their next frame in the normal way; the operating system or GDB
-     may have pushed their resume address manually onto the stack, so
-     it may be the very first instruction.  Even if the resume address
-     was not manually pushed, they expect to be returned to.  */
-  if (this_type != NORMAL_FRAME)
-    return pc;
-
-  /* If THIS frame is not inner most (i.e., NEXT isn't the sentinel),
-     and NEXT is `normal' (i.e., not a sigtramp, dummy, ....) THIS
-     frame's PC ends up pointing at the instruction fallowing the
-     "call".  Adjust that PC value so that it falls on the call
-     instruction (which, hopefully, falls within THIS frame's code
-     block).  So far it's proved to be a very good approximation.  See
-     get_frame_type() for why ->type can't be used.  */
-  if (next_frame->level >= 0
-      && get_frame_type (next_frame) == NORMAL_FRAME)
-    --pc;
-  return pc;
-}
+  CORE_ADDR pc = get_frame_pc (this_frame);
+
+  struct frame_info *next_frame = this_frame->next;
+
+  /* Calling get_frame_pc returns the resume address for THIS_FRAME.
+     Normally the resume address is inside the body of the function
+     associated with THIS_FRAME, but there is a special case: when
+     calling a function which the compiler knows will never return
+     (for instance abort), the call may be the very last instruction
+     in the calling function.  The resume address will point after the
+     call and may be at the beginning of a different function
+     entirely.
+
+     If THIS_FRAME is a signal frame or dummy frame, then we should
+     not adjust the unwound PC.  For a dummy frame, GDB pushed the
+     resume address manually onto the stack.  For a signal frame, the
+     OS may have pushed the resume address manually and invoked the
+     handler (e.g. GNU/Linux), or invoked the trampoline which called
+     the signal handler - but in either case the signal handler is
+     expected to return to the trampoline.  So in both of these
+     cases we know that the resume address is executable and
+     related.  So we only need to adjust the PC if THIS_FRAME
+     is a normal function.
+
+     If the program has been interrupted while THIS_FRAME is current,
+     then clearly the resume address is inside the associated
+     function.  There are three kinds of interruption: debugger stop
+     (next frame will be SENTINEL_FRAME), operating system
+     signal or exception (next frame will be SIGTRAMP_FRAME),
+     or debugger-induced function call (next frame will be
+     DUMMY_FRAME).  So we only need to adjust the PC if
+     NEXT_FRAME is a normal function.
+
+     We check the type of NEXT_FRAME first, since it is already
+     known; frame type is determined by the unwinder, and since
+     we have THIS_FRAME we've already selected an unwinder for
+     NEXT_FRAME.  */
+  if (get_frame_type (next_frame) == NORMAL_FRAME
+      && get_frame_type (this_frame) == NORMAL_FRAME)
+    return pc - 1;
 
-CORE_ADDR
-get_frame_address_in_block (struct frame_info *this_frame)
-{
-  return frame_unwind_address_in_block (this_frame->next,
-					get_frame_type (this_frame));
+  return pc;
 }
 
 static int
@@ -1572,12 +1638,12 @@ get_frame_base_address (struct frame_info *fi)
   if (get_frame_type (fi) != NORMAL_FRAME)
     return 0;
   if (fi->base == NULL)
-    fi->base = frame_base_find_by_frame (fi->next);
+    fi->base = frame_base_find_by_frame (fi);
   /* Sneaky: If the low-level unwind and high-level base code share a
      common unwinder, let them share the prologue cache.  */
   if (fi->base->unwind == fi->unwind)
-    return fi->base->this_base (fi->next, &fi->prologue_cache);
-  return fi->base->this_base (fi->next, &fi->base_cache);
+    return fi->base->this_base (fi, &fi->prologue_cache);
+  return fi->base->this_base (fi, &fi->base_cache);
 }
 
 CORE_ADDR
@@ -1588,14 +1654,12 @@ get_frame_locals_address (struct frame_info *fi)
     return 0;
   /* If there isn't a frame address method, find it.  */
   if (fi->base == NULL)
-    fi->base = frame_base_find_by_frame (fi->next);
+    fi->base = frame_base_find_by_frame (fi);
   /* Sneaky: If the low-level unwind and high-level base code share a
      common unwinder, let them share the prologue cache.  */
   if (fi->base->unwind == fi->unwind)
-    cache = &fi->prologue_cache;
-  else
-    cache = &fi->base_cache;
-  return fi->base->this_locals (fi->next, cache);
+    return fi->base->this_locals (fi, &fi->prologue_cache);
+  return fi->base->this_locals (fi, &fi->base_cache);
 }
 
 CORE_ADDR
@@ -1606,14 +1670,12 @@ get_frame_args_address (struct frame_info *fi)
     return 0;
   /* If there isn't a frame address method, find it.  */
   if (fi->base == NULL)
-    fi->base = frame_base_find_by_frame (fi->next);
+    fi->base = frame_base_find_by_frame (fi);
   /* Sneaky: If the low-level unwind and high-level base code share a
      common unwinder, let them share the prologue cache.  */
   if (fi->base->unwind == fi->unwind)
-    cache = &fi->prologue_cache;
-  else
-    cache = &fi->base_cache;
-  return fi->base->this_args (fi->next, cache);
+    return fi->base->this_args (fi, &fi->prologue_cache);
+  return fi->base->this_args (fi, &fi->base_cache);
 }
 
 /* Level of the selected frame: 0 for innermost, 1 for its caller, ...
@@ -1634,43 +1696,10 @@ get_frame_type (struct frame_info *frame)
   if (frame->unwind == NULL)
     /* Initialize the frame's unwinder because that's what
        provides the frame's type.  */
-    frame->unwind = frame_unwind_find_by_frame (frame->next, 
-						&frame->prologue_cache);
+    frame->unwind = frame_unwind_find_by_frame (frame, &frame->prologue_cache);
   return frame->unwind->type;
 }
 
-void
-deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc)
-{
-  if (frame_debug)
-    fprintf_unfiltered (gdb_stdlog,
-			"{ deprecated_update_frame_pc_hack (frame=%d,pc=0x%s) }\n",
-			frame->level, paddr_nz (pc));
-  /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are
-     maintaining a locally allocated frame object.  Since such frames
-     are not in the frame chain, it isn't possible to assume that the
-     frame has a next.  Sigh.  */
-  if (frame->next != NULL)
-    {
-      /* While we're at it, update this frame's cached PC value, found
-	 in the next frame.  Oh for the day when "struct frame_info"
-	 is opaque and this hack on hack can just go away.  */
-      frame->next->prev_pc.value = pc;
-      frame->next->prev_pc.p = 1;
-    }
-}
-
-void
-deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base)
-{
-  if (frame_debug)
-    fprintf_unfiltered (gdb_stdlog,
-			"{ deprecated_update_frame_base_hack (frame=%d,base=0x%s) }\n",
-			frame->level, paddr_nz (base));
-  /* See comment in "frame.h".  */
-  frame->this_id.value.stack_addr = base;
-}
-
 /* Memory access methods.  */
 
 void
@@ -1698,8 +1727,8 @@ int
 safe_frame_unwind_memory (struct frame_info *this_frame,
 			  CORE_ADDR addr, gdb_byte *buf, int len)
 {
-  /* NOTE: read_memory_nobpt returns zero on success!  */
-  return !read_memory_nobpt (addr, buf, len);
+  /* NOTE: target_read_memory returns zero on success!  */
+  return !target_read_memory (addr, buf, len);
 }
 
 /* Architecture method.  */
@@ -1707,6 +1736,11 @@ safe_frame_unwind_memory (struct frame_info *this_frame,
 struct gdbarch *
 get_frame_arch (struct frame_info *this_frame)
 {
+  /* In the future, this function will return a per-frame
+     architecture instead of current_gdbarch.  Calling the
+     routine with a NULL value of this_frame is a bug!  */
+  gdb_assert (this_frame);
+
   return current_gdbarch;
 }
 
@@ -1715,25 +1749,18 @@ get_frame_arch (struct frame_info *this_frame)
 CORE_ADDR
 get_frame_sp (struct frame_info *this_frame)
 {
-  return frame_sp_unwind (this_frame->next);
-}
-
-CORE_ADDR
-frame_sp_unwind (struct frame_info *next_frame)
-{
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
   /* Normality - an architecture that provides a way of obtaining any
      frame inner-most address.  */
-  if (gdbarch_unwind_sp_p (current_gdbarch))
-    return gdbarch_unwind_sp (current_gdbarch, next_frame);
+  if (gdbarch_unwind_sp_p (gdbarch))
+    /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to
+       operate on THIS_FRAME now.  */
+    return gdbarch_unwind_sp (gdbarch, this_frame->next);
   /* Now things are really are grim.  Hope that the value returned by
      the gdbarch_sp_regnum register is meaningful.  */
-  if (gdbarch_sp_regnum (current_gdbarch) >= 0)
-    {
-      ULONGEST sp;
-      frame_unwind_unsigned_register (next_frame,
-				      gdbarch_sp_regnum (current_gdbarch), &sp);
-      return sp;
-    }
+  if (gdbarch_sp_regnum (gdbarch) >= 0)
+    return get_frame_register_unsigned (this_frame,
+					gdbarch_sp_regnum (gdbarch));
   internal_error (__FILE__, __LINE__, _("Missing unwind SP method"));
 }
 
@@ -1779,6 +1806,50 @@ frame_stop_reason_string (enum unwind_stop_reason reason)
     }
 }
 
+/* Clean up after a failed (wrong unwinder) attempt to unwind past
+   FRAME.  */
+
+static void
+frame_cleanup_after_sniffer (void *arg)
+{
+  struct frame_info *frame = arg;
+
+  /* The sniffer should not allocate a prologue cache if it did not
+     match this frame.  */
+  gdb_assert (frame->prologue_cache == NULL);
+
+  /* No sniffer should extend the frame chain; sniff based on what is
+     already certain.  */
+  gdb_assert (!frame->prev_p);
+
+  /* The sniffer should not check the frame's ID; that's circular.  */
+  gdb_assert (!frame->this_id.p);
+
+  /* Clear cached fields dependent on the unwinder.
+
+     The previous PC is independent of the unwinder, but the previous
+     function is not (see get_frame_address_in_block).  */
+  frame->prev_func.p = 0;
+  frame->prev_func.addr = 0;
+
+  /* Discard the unwinder last, so that we can easily find it if an assertion
+     in this function triggers.  */
+  frame->unwind = NULL;
+}
+
+/* Set FRAME's unwinder temporarily, so that we can call a sniffer.
+   Return a cleanup which should be called if unwinding fails, and
+   discarded if it succeeds.  */
+
+struct cleanup *
+frame_prepare_for_sniffer (struct frame_info *frame,
+			   const struct frame_unwind *unwind)
+{
+  gdb_assert (frame->unwind == NULL);
+  frame->unwind = unwind;
+  return make_cleanup (frame_cleanup_after_sniffer, frame);
+}
+
 extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */
 
 static struct cmd_list_element *set_backtrace_cmdlist;