asan: score: global-buffer-overflow

[deliverable/binutils-gdb.git] / gdb / dummy-frame.c

diff --git a/gdb/dummy-frame.c b/gdb/dummy-frame.c
index 2c5153ebe20d7e94e546eb4dccb3dd5e77022e95..3b76d456b7b134b5d524263898278ca98ff0b380 100644 (file)
--- a/gdb/dummy-frame.c
+++ b/gdb/dummy-frame.c
@@ -1,14 +1,12 @@
 /* Code dealing with dummy stack frames, for GDB, the GNU debugger.
 
 /* Code dealing with dummy stack frames, for GDB, the GNU debugger.
 

-   Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
-   1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002 Free Software
-   Foundation, Inc.
+   Copyright (C) 1986-2019 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
 
    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,
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,


@@ -17,9 +15,7 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    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., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

 
 
 #include "defs.h"
 
 
 #include "defs.h"


@@ -27,16 +23,46 @@
 #include "regcache.h"
 #include "frame.h"
 #include "inferior.h"
 #include "regcache.h"
 #include "frame.h"
 #include "inferior.h"

-#include "gdb_assert.h"

 #include "frame-unwind.h"
 #include "command.h"
 #include "gdbcmd.h"
 #include "frame-unwind.h"
 #include "command.h"
 #include "gdbcmd.h"

+#include "observable.h"
+#include "gdbthread.h"
+#include "infcall.h"
+#include "gdbarch.h"

 
 

-static void dummy_frame_this_id (struct frame_info *next_frame,
-                                void **this_prologue_cache,
-                                struct frame_id *this_id);
+struct dummy_frame_id
+{
+  /* This frame's ID.  Must match the value returned by
+     gdbarch_dummy_id.  */
+  struct frame_id id;
+
+  /* The thread this dummy_frame relates to.  */
+  thread_info *thread;
+};
+
+/* Return whether dummy_frame_id *ID1 and *ID2 are equal.  */
+
+static int
+dummy_frame_id_eq (struct dummy_frame_id *id1,
+                  struct dummy_frame_id *id2)
+{
+  return frame_id_eq (id1->id, id2->id) && id1->thread == id2->thread;
+}

 
 

-static int pc_in_dummy_frame (CORE_ADDR pc);
+/* List of dummy_frame destructors.  */
+
+struct dummy_frame_dtor_list
+{
+  /* Next element in the list or NULL if this is the last element.  */
+  struct dummy_frame_dtor_list *next;
+
+  /* If non-NULL, a destructor that is run when this dummy frame is freed.  */
+  dummy_frame_dtor_ftype *dtor;
+
+  /* Arbitrary data that is passed to DTOR.  */
+  void *dtor_data;
+};

 
 /* Dummy frame.  This saves the processor state just prior to setting
    up the inferior function call.  Older targets save the registers
 
 /* Dummy frame.  This saves the processor state just prior to setting
    up the inferior function call.  Older targets save the registers


@@ -46,407 +72,371 @@ struct dummy_frame
 {
   struct dummy_frame *next;
 
 {
   struct dummy_frame *next;
 

-  /* These values belong to the caller (the previous frame, the frame
-     that this unwinds back to).  */
-  CORE_ADDR pc;
-  CORE_ADDR fp;
-  CORE_ADDR sp;
-  CORE_ADDR top;
-  struct frame_id id;
-  struct regcache *regcache;
+  /* An id represents a dummy frame.  */
+  struct dummy_frame_id id;
+
+  /* The caller's state prior to the call.  */
+  struct infcall_suspend_state *caller_state;

 
 

-  /* Address range of the call dummy code.  Look for PC in the range
-     [LO..HI) (after allowing for DECR_PC_AFTER_BREAK).  */
-  CORE_ADDR call_lo;
-  CORE_ADDR call_hi;
+  /* First element of destructors list or NULL if there are no
+     destructors registered for this dummy_frame.  */
+  struct dummy_frame_dtor_list *dtor_list;

 };
 
 static struct dummy_frame *dummy_frame_stack = NULL;
 
 };
 
 static struct dummy_frame *dummy_frame_stack = NULL;
 

-/* Function: find_dummy_frame(pc, fp, sp)
+/* Push the caller's state, along with the dummy frame info, onto the
+   dummy-frame stack.  */
+
+void
+dummy_frame_push (struct infcall_suspend_state *caller_state,
+                 const frame_id *dummy_id, thread_info *thread)
+{
+  struct dummy_frame *dummy_frame;
+
+  dummy_frame = XCNEW (struct dummy_frame);
+  dummy_frame->caller_state = caller_state;
+  dummy_frame->id.id = (*dummy_id);
+  dummy_frame->id.thread = thread;
+  dummy_frame->next = dummy_frame_stack;
+  dummy_frame_stack = dummy_frame;
+}

 
 

-   Search the stack of dummy frames for one matching the given PC and
-   FP/SP.  Unlike pc_in_dummy_frame(), this function doesn't need to
-   adjust for DECR_PC_AFTER_BREAK.  This is because it is only legal
-   to call this function after the PC has been adjusted.  */
+/* Remove *DUMMY_PTR from the dummy frame stack.  */

 
 

-static struct dummy_frame *
-find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp)
+static void
+remove_dummy_frame (struct dummy_frame **dummy_ptr)

 {
 {

-  struct dummy_frame *dummyframe;
+  struct dummy_frame *dummy = *dummy_ptr;

 
 

-  for (dummyframe = dummy_frame_stack; dummyframe != NULL;
-       dummyframe = dummyframe->next)
+  while (dummy->dtor_list != NULL)

     {
     {

-      /* Does the PC fall within the dummy frame's breakpoint
-         instruction.  If not, discard this one.  */
-      if (!(pc >= dummyframe->call_lo && pc < dummyframe->call_hi))
-       continue;
-      /* Does the FP match?  */
-      if (dummyframe->top != 0)
-       {
-         /* If the target architecture explicitly saved the
-            top-of-stack before the inferior function call, assume
-            that that same architecture will always pass in an FP
-            (frame base) value that eactly matches that saved TOS.
-            Don't check the saved SP and SP as they can lead to false
-            hits.  */
-         if (fp != dummyframe->top)
-           continue;
-       }
-      else
-       {
-         /* An older target that hasn't explicitly or implicitly
-             saved the dummy frame's top-of-stack.  Try matching the
-             FP against the saved SP and FP.  NOTE: If you're trying
-             to fix a problem with GDB not correctly finding a dummy
-             frame, check the comments that go with FRAME_ALIGN() and
-             UNWIND_DUMMY_ID().  */
-         if (fp != dummyframe->fp && fp != dummyframe->sp)
-           continue;
-       }
-      /* The FP matches this dummy frame.  */
-      return dummyframe;
+      struct dummy_frame_dtor_list *list = dummy->dtor_list;
+
+      dummy->dtor_list = list->next;
+      list->dtor (list->dtor_data, 0);
+      xfree (list);

     }
 
     }
 

-  return NULL;
+  *dummy_ptr = dummy->next;
+  discard_infcall_suspend_state (dummy->caller_state);
+  xfree (dummy);

 }
 
 }
 

-struct regcache *
-deprecated_find_dummy_frame_regcache (CORE_ADDR pc, CORE_ADDR fp)
-{
-  struct dummy_frame *dummy = find_dummy_frame (pc, fp);
-  if (dummy != NULL)
-    return dummy->regcache;
-  else
-    return NULL;
-}
+/* Delete any breakpoint B which is a momentary breakpoint for return from
+   inferior call matching DUMMY_VOIDP.  */

 
 

-char *
-deprecated_generic_find_dummy_frame (CORE_ADDR pc, CORE_ADDR fp)
+static bool
+pop_dummy_frame_bpt (struct breakpoint *b, struct dummy_frame *dummy)

 {
 {

-  struct regcache *regcache = deprecated_find_dummy_frame_regcache (pc, fp);
-  if (regcache == NULL)
-    return NULL;
-  return deprecated_grub_regcache_for_registers (regcache);
-}
+  if (b->thread == dummy->id.thread->global_num
+      && b->disposition == disp_del && frame_id_eq (b->frame_id, dummy->id.id))
+    {
+      while (b->related_breakpoint != b)
+       delete_breakpoint (b->related_breakpoint);

 
 

-/* Function: pc_in_call_dummy (pc, sp, fp)
+      delete_breakpoint (b);

 
 

-   Return true if the PC falls in a dummy frame created by gdb for an
-   inferior call.  The code below which allows DECR_PC_AFTER_BREAK is
-   for infrun.c, which may give the function a PC without that
-   subtracted out.  */
+      /* Stop the traversal.  */
+      return true;
+    }

 
 

-int
-deprecated_pc_in_call_dummy (CORE_ADDR pc, CORE_ADDR sp, CORE_ADDR fp)
-{
-  return pc_in_dummy_frame (pc);
+  /* Continue the traversal.  */
+  return false;

 }
 
 }
 

-/* Return non-zero if the PC falls in a dummy frame.
+/* Pop *DUMMY_PTR, restoring program state to that before the
+   frame was created.  */

 
 

-   The code below which allows DECR_PC_AFTER_BREAK is for infrun.c,
-   which may give the function a PC without that subtracted out.
+static void
+pop_dummy_frame (struct dummy_frame **dummy_ptr)
+{
+  struct dummy_frame *dummy = *dummy_ptr;

 
 

-   FIXME: cagney/2002-11-23: This is silly.  Surely "infrun.c" can
-   figure out what the real PC (as in the resume address) is BEFORE
-   calling this function (Oh, and I'm not even sure that this function
-   is called with an decremented PC, the call to pc_in_call_dummy() in
-   that file is conditional on
-   !DEPRECATED_CALL_DUMMY_BREAKPOINT_OFFSET_P yet generic dummy
-   targets set DEPRECATED_CALL_DUMMY_BREAKPOINT_OFFSET. True?).  */
+  gdb_assert (dummy->id.thread == inferior_thread ());

 
 

-static int
-pc_in_dummy_frame (CORE_ADDR pc)
-{
-  struct dummy_frame *dummyframe;
-  for (dummyframe = dummy_frame_stack;
-       dummyframe != NULL;
-       dummyframe = dummyframe->next)
+  while (dummy->dtor_list != NULL)

     {
     {

-      if ((pc >= dummyframe->call_lo)
-         && (pc < dummyframe->call_hi + DECR_PC_AFTER_BREAK))
-       return 1;
+      struct dummy_frame_dtor_list *list = dummy->dtor_list;
+
+      dummy->dtor_list = list->next;
+      list->dtor (list->dtor_data, 1);
+      xfree (list);

     }
     }

-  return 0;
+
+  restore_infcall_suspend_state (dummy->caller_state);
+
+  iterate_over_breakpoints ([dummy] (breakpoint* bp)
+    {
+      return pop_dummy_frame_bpt (bp, dummy);
+    });
+
+  /* restore_infcall_control_state frees inf_state,
+     all that remains is to pop *dummy_ptr.  */
+  *dummy_ptr = dummy->next;
+  xfree (dummy);
+
+  /* We've made right mess of GDB's local state, just discard
+     everything.  */
+  reinit_frame_cache ();

 }
 
 }
 

-/* Function: read_register_dummy 
-   Find a saved register from before GDB calls a function in the inferior */
+/* Look up DUMMY_ID.
+   Return NULL if not found.  */

 
 

-CORE_ADDR
-deprecated_read_register_dummy (CORE_ADDR pc, CORE_ADDR fp, int regno)
+static struct dummy_frame **
+lookup_dummy_frame (struct dummy_frame_id *dummy_id)

 {
 {

-  struct regcache *dummy_regs = deprecated_find_dummy_frame_regcache (pc, fp);
+  struct dummy_frame **dp;

 
 

-  if (dummy_regs)
+  for (dp = &dummy_frame_stack; *dp != NULL; dp = &(*dp)->next)

     {
     {

-      /* NOTE: cagney/2002-08-12: Replaced a call to
-        regcache_raw_read_as_address() with a call to
-        regcache_cooked_read_unsigned().  The old, ...as_address
-        function was eventually calling extract_unsigned_integer (nee
-        extract_address) to unpack the registers value.  The below is
-        doing an unsigned extract so that it is functionally
-        equivalent.  The read needs to be cooked as, otherwise, it
-        will never correctly return the value of a register in the
-        [NUM_REGS .. NUM_REGS+NUM_PSEUDO_REGS) range.  */
-      ULONGEST val;
-      regcache_cooked_read_unsigned (dummy_regs, regno, &val);
-      return val;
+      if (dummy_frame_id_eq (&(*dp)->id, dummy_id))
+       return dp;

     }
     }

-  else
-    return 0;
+
+  return NULL;

 }
 
 }
 

-/* Save all the registers on the dummy frame stack.  Most ports save the
-   registers on the target stack.  This results in lots of unnecessary memory
-   references, which are slow when debugging via a serial line.  Instead, we
-   save all the registers internally, and never write them to the stack.  The
-   registers get restored when the called function returns to the entry point,
-   where a breakpoint is laying in wait.  */
+/* Find the dummy frame by DUMMY_ID and THREAD, and pop it, restoring
+   program state to that before the frame was created.
+   On return reinit_frame_cache has been called.
+   If the frame isn't found, flag an internal error.  */

 
 void
 
 void

-generic_push_dummy_frame (void)
+dummy_frame_pop (frame_id dummy_id, thread_info *thread)

 {
 {

-  struct dummy_frame *dummy_frame;
-  CORE_ADDR fp = get_frame_base (get_current_frame ());
-
-  /* check to see if there are stale dummy frames, 
-     perhaps left over from when a longjump took us out of a 
-     function that was called by the debugger */
-
-  dummy_frame = dummy_frame_stack;
-  while (dummy_frame)
-    if (INNER_THAN (dummy_frame->fp, fp))      /* stale -- destroy! */
-      {
-       dummy_frame_stack = dummy_frame->next;
-       regcache_xfree (dummy_frame->regcache);
-       xfree (dummy_frame);
-       dummy_frame = dummy_frame_stack;
-      }
-    else
-      dummy_frame = dummy_frame->next;
-
-  dummy_frame = xmalloc (sizeof (struct dummy_frame));
-  dummy_frame->regcache = regcache_xmalloc (current_gdbarch);
-
-  dummy_frame->pc = read_pc ();
-  dummy_frame->sp = read_sp ();
-  dummy_frame->top = 0;
-  dummy_frame->fp = fp;
-  dummy_frame->id = get_frame_id (get_current_frame ());
-  regcache_cpy (dummy_frame->regcache, current_regcache);
-  dummy_frame->next = dummy_frame_stack;
-  dummy_frame_stack = dummy_frame;
+  struct dummy_frame **dp;
+  struct dummy_frame_id id = { dummy_id, thread };
+
+  dp = lookup_dummy_frame (&id);
+  gdb_assert (dp != NULL);
+
+  pop_dummy_frame (dp);

 }
 
 }
 

+/* Find the dummy frame by DUMMY_ID and PTID and drop it.  Do nothing
+   if it is not found.  Do not restore its state into inferior, just
+   free its memory.  */
+

 void
 void

-generic_save_dummy_frame_tos (CORE_ADDR sp)
+dummy_frame_discard (struct frame_id dummy_id, thread_info *thread)

 {
 {

-  dummy_frame_stack->top = sp;
+  struct dummy_frame **dp;
+  struct dummy_frame_id id = { dummy_id, thread };
+
+  dp = lookup_dummy_frame (&id);
+  if (dp)
+    remove_dummy_frame (dp);

 }
 
 }
 

-/* Record the upper/lower bounds on the address of the call dummy.  */
+/* See dummy-frame.h.  */

 
 void
 
 void

-generic_save_call_dummy_addr (CORE_ADDR lo, CORE_ADDR hi)
+register_dummy_frame_dtor (frame_id dummy_id, thread_info *thread,
+                          dummy_frame_dtor_ftype *dtor, void *dtor_data)

 {
 {

-  dummy_frame_stack->call_lo = lo;
-  dummy_frame_stack->call_hi = hi;
+  struct dummy_frame_id id = { dummy_id, thread };
+  struct dummy_frame **dp, *d;
+  struct dummy_frame_dtor_list *list;
+
+  dp = lookup_dummy_frame (&id);
+  gdb_assert (dp != NULL);
+  d = *dp;
+  list = XNEW (struct dummy_frame_dtor_list);
+  list->next = d->dtor_list;
+  d->dtor_list = list;
+  list->dtor = dtor;
+  list->dtor_data = dtor_data;

 }
 
 }
 

-/* Discard the innermost dummy frame from the dummy frame stack
-   (passed in as a parameter).  */
+/* See dummy-frame.h.  */

 
 

-static void
-discard_innermost_dummy (struct dummy_frame **stack)
+int
+find_dummy_frame_dtor (dummy_frame_dtor_ftype *dtor, void *dtor_data)

 {
 {

-  struct dummy_frame *tbd = (*stack);
-  (*stack) = (*stack)->next;
-  regcache_xfree (tbd->regcache);
-  xfree (tbd);
+  struct dummy_frame *d;
+
+  for (d = dummy_frame_stack; d != NULL; d = d->next)
+    {
+      struct dummy_frame_dtor_list *list;
+
+      for (list = d->dtor_list; list != NULL; list = list->next)
+       if (list->dtor == dtor && list->dtor_data == dtor_data)
+         return 1;
+    }
+  return 0;

 }
 
 }
 

-void
-deprecated_pop_dummy_frame (void)
-{
-  struct dummy_frame *dummy_frame = dummy_frame_stack;
+/* There may be stale dummy frames, perhaps left over from when an uncaught
+   longjmp took us out of a function that was called by the debugger.  Clean
+   them up at least once whenever we start a new inferior.  */

 
 

-  /* FIXME: what if the first frame isn't the right one, eg..
-     because one call-by-hand function has done a longjmp into another one? */
+static void
+cleanup_dummy_frames (struct target_ops *target, int from_tty)
+{
+  while (dummy_frame_stack != NULL)
+    remove_dummy_frame (&dummy_frame_stack);
+}

 
 

-  if (!dummy_frame)
-    error ("Can't pop dummy frame!");
-  regcache_cpy (current_regcache, dummy_frame->regcache);
-  flush_cached_frames ();
+/* Return the dummy frame cache, it contains both the ID, and a
+   pointer to the regcache.  */
+struct dummy_frame_cache
+{
+  struct frame_id this_id;
+  readonly_detached_regcache *prev_regcache;
+};

 
 

-  discard_innermost_dummy (&dummy_frame_stack);
+static int
+dummy_frame_sniffer (const struct frame_unwind *self,
+                    struct frame_info *this_frame,
+                    void **this_prologue_cache)
+{
+  /* When unwinding a normal frame, the stack structure is determined
+     by analyzing the frame's function's code (be it using brute force
+     prologue analysis, or the dwarf2 CFI).  In the case of a dummy
+     frame, that simply isn't possible.  The PC is either the program
+     entry point, or some random address on the stack.  Trying to use
+     that PC to apply standard frame ID unwind techniques is just
+     asking for trouble.  */
+  
+  /* Don't bother unless there is at least one dummy frame.  */
+  if (dummy_frame_stack != NULL)
+    {
+      struct dummy_frame *dummyframe;
+      /* Use an architecture specific method to extract this frame's
+        dummy ID, assuming it is a dummy frame.  */
+      struct frame_id this_id
+       = gdbarch_dummy_id (get_frame_arch (this_frame), this_frame);
+      struct dummy_frame_id dummy_id = { this_id, inferior_thread () };
+
+      /* Use that ID to find the corresponding cache entry.  */
+      for (dummyframe = dummy_frame_stack;
+          dummyframe != NULL;
+          dummyframe = dummyframe->next)
+       {
+         if (dummy_frame_id_eq (&dummyframe->id, &dummy_id))
+           {
+             struct dummy_frame_cache *cache;
+
+             cache = FRAME_OBSTACK_ZALLOC (struct dummy_frame_cache);
+             cache->prev_regcache = get_infcall_suspend_state_regcache
+                                                  (dummyframe->caller_state);
+             cache->this_id = this_id;
+             (*this_prologue_cache) = cache;
+             return 1;
+           }
+       }
+    }
+  return 0;

 }
 
 /* Given a call-dummy dummy-frame, return the registers.  Here the
    register value is taken from the local copy of the register buffer.  */
 
 }
 
 /* Given a call-dummy dummy-frame, return the registers.  Here the
    register value is taken from the local copy of the register buffer.  */
 

-static void
-dummy_frame_prev_register (struct frame_info *next_frame,
+static struct value *
+dummy_frame_prev_register (struct frame_info *this_frame,

                           void **this_prologue_cache,
                           void **this_prologue_cache,

-                          int regnum, int *optimized,
-                          enum lval_type *lvalp, CORE_ADDR *addrp,
-                          int *realnum, void *bufferp)
+                          int regnum)

 {
 {

-  struct dummy_frame *dummy;
-  struct frame_id id;
+  struct dummy_frame_cache *cache
+    = (struct dummy_frame_cache *) *this_prologue_cache;
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  struct value *reg_val;

 
 

-  /* Call the ID method which, if at all possible, will set the
-     prologue cache.  */
-  dummy_frame_this_id (next_frame, this_prologue_cache, &id);
-  dummy = (*this_prologue_cache);
-  gdb_assert (dummy != NULL);
+  /* The dummy-frame sniffer always fills in the cache.  */
+  gdb_assert (cache != NULL);

 
   /* Describe the register's location.  Generic dummy frames always
      have the register value in an ``expression''.  */
 
   /* Describe the register's location.  Generic dummy frames always
      have the register value in an ``expression''.  */

-  *optimized = 0;
-  *lvalp = not_lval;
-  *addrp = 0;
-  *realnum = -1;
-
-  /* If needed, find and return the value of the register.  */
-  if (bufferp != NULL)
-    {
-      /* Return the actual value.  */
-      /* Use the regcache_cooked_read() method so that it, on the fly,
-         constructs either a raw or pseudo register from the raw
-         register cache.  */
-      regcache_cooked_read (dummy->regcache, regnum, bufferp);
-    }
+  reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
+
+  /* Use the regcache_cooked_read() method so that it, on the fly,
+     constructs either a raw or pseudo register from the raw
+     register cache.  */
+  cache->prev_regcache->cooked_read (regnum,
+                                    value_contents_writeable (reg_val));
+  return reg_val;

 }
 
 }
 

-/* Assuming that THIS frame is a dummy (remember, the NEXT and not
-   THIS frame is passed in), return the ID of THIS frame.  That ID is
+/* Assuming that THIS_FRAME is a dummy, return its ID.  That ID is

    determined by examining the NEXT frame's unwound registers using
    determined by examining the NEXT frame's unwound registers using

-   the method unwind_dummy_id().  As a side effect, THIS dummy frame's
-   dummy cache is located and and saved in THIS_PROLOGUE_CACHE.  */
+   the method dummy_id().  As a side effect, THIS dummy frame's
+   dummy cache is located and saved in THIS_PROLOGUE_CACHE.  */

 
 static void
 
 static void

-dummy_frame_this_id (struct frame_info *next_frame,
+dummy_frame_this_id (struct frame_info *this_frame,

                     void **this_prologue_cache,
                     struct frame_id *this_id)
 {
                     void **this_prologue_cache,
                     struct frame_id *this_id)
 {

-  struct dummy_frame *dummy = (*this_prologue_cache);
-  if (dummy != NULL)
-    {
-      (*this_id) = dummy->id;
-      return;
-    }
-  /* When unwinding a normal frame, the stack structure is determined
-     by analyzing the frame's function's code (be it using brute force
-     prologue analysis, or the dwarf2 CFI).  In the case of a dummy
-     frame, that simply isn't possible.  The The PC is either the
-     program entry point, or some random address on the stack.  Trying
-     to use that PC to apply standard frame ID unwind techniques is
-     just asking for trouble.  */
-  if (gdbarch_unwind_dummy_id_p (current_gdbarch))
-    {
-      /* Use an architecture specific method to extract the prev's
-        dummy ID from the next frame.  Note that this method uses
-        frame_register_unwind to obtain the register values needed to
-        determine the dummy frame's ID.  */
-      (*this_id) = gdbarch_unwind_dummy_id (current_gdbarch, next_frame);
-    }
-  else if (frame_relative_level (next_frame) < 0)
-    {
-      /* We're unwinding a sentinel frame, the PC of which is pointing
-        at a stack dummy.  Fake up the dummy frame's ID using the
-        same sequence as is found a traditional unwinder.  Once all
-        architectures supply the unwind_dummy_id method, this code
-        can go away.  */
-      (*this_id) = frame_id_build (deprecated_read_fp (), read_pc ());
-    }
-  else if (legacy_frame_p (current_gdbarch)
-          && get_prev_frame (next_frame))
-    {
-      /* Things are looking seriously grim!  Assume that the legacy
-         get_prev_frame code has already created THIS frame and linked
-         it in to the frame chain (a pretty bold assumption), extract
-         the ID from THIS base / pc.  */
-      (*this_id) = frame_id_build (get_frame_base (get_prev_frame (next_frame)),
-                                  get_frame_pc (get_prev_frame (next_frame)));
-    }
-  else
-    {
-      /* Ouch!  We're not trying to find the innermost frame's ID yet
-        we're trying to unwind to a dummy.  The architecture must
-        provide the unwind_dummy_id() method.  Abandon the unwind
-        process but only after first warning the user.  */
-      internal_warning (__FILE__, __LINE__,
-                       "Missing unwind_dummy_id architecture method");
-      (*this_id) = null_frame_id;
-      return;
-    }
-  (*this_prologue_cache) = find_dummy_frame ((*this_id).code_addr,
-                                            (*this_id).stack_addr);
+  /* The dummy-frame sniffer always fills in the cache.  */
+  struct dummy_frame_cache *cache
+    = (struct dummy_frame_cache *) *this_prologue_cache;
+
+  gdb_assert (cache != NULL);
+  (*this_id) = cache->this_id;

 }
 
 }
 

-static struct frame_unwind dummy_frame_unwind =
+const struct frame_unwind dummy_frame_unwind =

 {
   DUMMY_FRAME,
 {
   DUMMY_FRAME,

+  default_frame_unwind_stop_reason,

   dummy_frame_this_id,
   dummy_frame_this_id,

-  dummy_frame_prev_register
+  dummy_frame_prev_register,
+  NULL,
+  dummy_frame_sniffer,

 };
 
 };
 

-const struct frame_unwind *
-dummy_frame_sniffer (struct frame_info *next_frame)
+/* See dummy-frame.h.  */
+
+struct frame_id
+default_dummy_id (struct gdbarch *gdbarch, struct frame_info *this_frame)

 {
 {

-  CORE_ADDR pc = frame_pc_unwind (next_frame);
-  gdb_assert (DEPRECATED_USE_GENERIC_DUMMY_FRAMES);
-  if (pc_in_dummy_frame (pc))
-    return &dummy_frame_unwind;
-  else
-    return NULL;
+  CORE_ADDR sp, pc;
+
+  sp = get_frame_sp (this_frame);
+  pc = get_frame_pc (this_frame);
+  return frame_id_build (sp, pc);

 }
 
 static void
 fprint_dummy_frames (struct ui_file *file)
 {
   struct dummy_frame *s;
 }
 
 static void
 fprint_dummy_frames (struct ui_file *file)
 {
   struct dummy_frame *s;

+

   for (s = dummy_frame_stack; s != NULL; s = s->next)
     {
       gdb_print_host_address (s, file);
       fprintf_unfiltered (file, ":");
   for (s = dummy_frame_stack; s != NULL; s = s->next)
     {
       gdb_print_host_address (s, file);
       fprintf_unfiltered (file, ":");

-      fprintf_unfiltered (file, " pc=0x%s", paddr (s->pc));
-      fprintf_unfiltered (file, " fp=0x%s", paddr (s->fp));
-      fprintf_unfiltered (file, " sp=0x%s", paddr (s->sp));
-      fprintf_unfiltered (file, " top=0x%s", paddr (s->top));

       fprintf_unfiltered (file, " id=");
       fprintf_unfiltered (file, " id=");

-      fprint_frame_id (file, s->id);
-      fprintf_unfiltered (file, " call_lo=0x%s", paddr (s->call_lo));
-      fprintf_unfiltered (file, " call_hi=0x%s", paddr (s->call_hi));
+      fprint_frame_id (file, s->id.id);
+      fprintf_unfiltered (file, ", ptid=%s",
+                         target_pid_to_str (s->id.thread->ptid).c_str ());

       fprintf_unfiltered (file, "\n");
     }
 }
 
 static void
       fprintf_unfiltered (file, "\n");
     }
 }
 
 static void

-maintenance_print_dummy_frames (char *args, int from_tty)
+maintenance_print_dummy_frames (const char *args, int from_tty)

 {
   if (args == NULL)
     fprint_dummy_frames (gdb_stdout);
   else
     {
 {
   if (args == NULL)
     fprint_dummy_frames (gdb_stdout);
   else
     {

-      struct ui_file *file = gdb_fopen (args, "w");
-      if (file == NULL)
-       perror_with_name ("maintenance print dummy-frames");
-      fprint_dummy_frames (file);    
-      ui_file_delete (file);
+      stdio_file file;
+
+      if (!file.open (args, "w"))
+       perror_with_name (_("maintenance print dummy-frames"));
+      fprint_dummy_frames (&file);

     }
 }
 
     }
 }
 

-extern void _initialize_dummy_frame (void);
-

 void
 _initialize_dummy_frame (void)
 {
   add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames,
 void
 _initialize_dummy_frame (void)
 {
   add_cmd ("dummy-frames", class_maintenance, maintenance_print_dummy_frames,

-          "Print the contents of the internal dummy-frame stack.",
+          _("Print the contents of the internal dummy-frame stack."),

           &maintenanceprintlist);
 
           &maintenanceprintlist);
 

+  gdb::observers::inferior_created.attach (cleanup_dummy_frames);

 }
 }