X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gdb%2Fframe-unwind.c;h=3334c472d0202b546f5eea17e27ec6cbbabc7476;hb=refs%2Fheads%2Fconcurrent-displaced-stepping-2020-04-01;hp=ac26a643a840fa791493f48c4d65bc7ca598b119;hpb=4ea2acf05c76ed88f686c27faaf46ab88bfa0f79;p=deliverable%2Fbinutils-gdb.git

diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c
index ac26a643a8..3334c472d0 100644
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -1,12 +1,12 @@
 /* Definitions for frame unwinder, for GDB, the GNU debugger.
 
-   Copyright 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003-2020 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,
@@ -15,94 +15,320 @@
    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 "frame.h"
 #include "frame-unwind.h"
-#include "gdb_assert.h"
 #include "dummy-frame.h"
+#include "inline-frame.h"
+#include "value.h"
+#include "regcache.h"
 #include "gdb_obstack.h"
+#include "target.h"
+#include "gdbarch.h"
+#include "dwarf2/frame-tailcall.h"
 
 static struct gdbarch_data *frame_unwind_data;
 
 struct frame_unwind_table_entry
 {
-  frame_unwind_sniffer_ftype *sniffer;
   const struct frame_unwind *unwinder;
   struct frame_unwind_table_entry *next;
 };
 
 struct frame_unwind_table
 {
-  struct frame_unwind_table_entry *head;
-  struct frame_unwind_table_entry **tail;
+  struct frame_unwind_table_entry *list;
+  /* The head of the OSABI part of the search list.  */
+  struct frame_unwind_table_entry **osabi_head;
 };
 
+/* A helper function to add an unwinder to a list.  LINK says where to
+   install the new unwinder.  The new link is returned.  */
+
+static struct frame_unwind_table_entry **
+add_unwinder (struct obstack *obstack, const struct frame_unwind *unwinder,
+	      struct frame_unwind_table_entry **link)
+{
+  *link = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
+  (*link)->unwinder = unwinder;
+  return &(*link)->next;
+}
+
 static void *
 frame_unwind_init (struct obstack *obstack)
 {
   struct frame_unwind_table *table
     = OBSTACK_ZALLOC (obstack, struct frame_unwind_table);
-  table->head = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
-  table->head->sniffer = dummy_frame_sniffer;
-  table->tail = &table->head->next;
+
+  /* Start the table out with a few default sniffers.  OSABI code
+     can't override this.  */
+  struct frame_unwind_table_entry **link = &table->list;
+
+  link = add_unwinder (obstack, &dummy_frame_unwind, link);
+  /* The DWARF tailcall sniffer must come before the inline sniffer.
+     Otherwise, we can end up in a situation where a DWARF frame finds
+     tailcall information, but then the inline sniffer claims a frame
+     before the tailcall sniffer, resulting in confusion.  This is
+     safe to do always because the tailcall sniffer can only ever be
+     activated if the newer frame was created using the DWARF
+     unwinder, and it also found tailcall information.  */
+  link = add_unwinder (obstack, &dwarf2_tailcall_frame_unwind, link);
+  link = add_unwinder (obstack, &inline_frame_unwind, link);
+
+  /* The insertion point for OSABI sniffers.  */
+  table->osabi_head = link;
   return table;
 }
 
 void
-frame_unwind_append_sniffer (struct gdbarch *gdbarch,
-			     frame_unwind_sniffer_ftype *sniffer)
+frame_unwind_prepend_unwinder (struct gdbarch *gdbarch,
+				const struct frame_unwind *unwinder)
 {
-  struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
-  (*table->tail) = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
-  (*table->tail)->sniffer = sniffer;
-  table->tail = &((*table->tail)->next);
+  struct frame_unwind_table *table
+    = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
+  struct frame_unwind_table_entry *entry;
+
+  /* Insert the new entry at the start of the list.  */
+  entry = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
+  entry->unwinder = unwinder;
+  entry->next = (*table->osabi_head);
+  (*table->osabi_head) = entry;
 }
 
 void
-frame_unwind_register_unwinder (struct gdbarch *gdbarch,
-				const struct frame_unwind *unwinder)
+frame_unwind_append_unwinder (struct gdbarch *gdbarch,
+			      const struct frame_unwind *unwinder)
 {
-  struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
-  (*table->tail) = GDBARCH_OBSTACK_ZALLOC (gdbarch,
-					   struct frame_unwind_table_entry);
-  (*table->tail)->unwinder = unwinder;
-  table->tail = &((*table->tail)->next);
+  struct frame_unwind_table *table
+    = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
+  struct frame_unwind_table_entry **ip;
+
+  /* Find the end of the list and insert the new entry there.  */
+  for (ip = table->osabi_head; (*ip) != NULL; ip = &(*ip)->next);
+  (*ip) = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry);
+  (*ip)->unwinder = unwinder;
 }
 
-const struct frame_unwind *
-frame_unwind_find_by_frame (struct frame_info *next_frame, void **this_cache)
+/* Call SNIFFER from UNWINDER.  If it succeeded set UNWINDER for
+   THIS_FRAME and return 1.  Otherwise the function keeps THIS_FRAME
+   unchanged and returns 0.  */
+
+static int
+frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
+                          const struct frame_unwind *unwinder)
 {
-  int i;
-  struct gdbarch *gdbarch = get_frame_arch (next_frame);
-  struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
-  struct frame_unwind_table_entry *entry;
-  for (entry = table->head; entry != NULL; entry = entry->next)
+  int res = 0;
+
+  frame_prepare_for_sniffer (this_frame, unwinder);
+
+  try
     {
-      if (entry->sniffer != NULL)
-	{
-	  const struct frame_unwind *desc = NULL;
-	  desc = entry->sniffer (next_frame);
-	  if (desc != NULL)
-	    return desc;
-	}
-      if (entry->unwinder != NULL)
+      res = unwinder->sniffer (unwinder, this_frame, this_cache);
+    }
+  catch (const gdb_exception &ex)
+    {
+      /* Catch all exceptions, caused by either interrupt or error.
+	 Reset *THIS_CACHE.  */
+      *this_cache = NULL;
+      frame_cleanup_after_sniffer (this_frame);
+
+      if (ex.error == NOT_AVAILABLE_ERROR)
 	{
-	  if (entry->unwinder->sniffer (entry->unwinder, next_frame,
-					this_cache))
-	    return entry->unwinder;
+	  /* This usually means that not even the PC is available,
+	     thus most unwinders aren't able to determine if they're
+	     the best fit.  Keep trying.  Fallback prologue unwinders
+	     should always accept the frame.  */
+	  return 0;
 	}
+      throw;
+    }
+
+  if (res)
+    return 1;
+  else
+    {
+      /* Don't set *THIS_CACHE to NULL here, because sniffer has to do
+	 so.  */
+      frame_cleanup_after_sniffer (this_frame);
+      return 0;
     }
-  return legacy_saved_regs_unwind;
+  gdb_assert_not_reached ("frame_unwind_try_unwinder");
+}
+
+/* Iterate through sniffers for THIS_FRAME frame until one returns with an
+   unwinder implementation.  THIS_FRAME->UNWIND must be NULL, it will get set
+   by this function.  Possibly initialize THIS_CACHE.  */
+
+void
+frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache)
+{
+  struct gdbarch *gdbarch = get_frame_arch (this_frame);
+  struct frame_unwind_table *table
+    = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data);
+  struct frame_unwind_table_entry *entry;
+  const struct frame_unwind *unwinder_from_target;
+
+  unwinder_from_target = target_get_unwinder ();
+  if (unwinder_from_target != NULL
+      && frame_unwind_try_unwinder (this_frame, this_cache,
+                                   unwinder_from_target))
+    return;
+
+  unwinder_from_target = target_get_tailcall_unwinder ();
+  if (unwinder_from_target != NULL
+      && frame_unwind_try_unwinder (this_frame, this_cache,
+                                   unwinder_from_target))
+    return;
+
+  for (entry = table->list; entry != NULL; entry = entry->next)
+    if (frame_unwind_try_unwinder (this_frame, this_cache, entry->unwinder))
+      return;
+
+  internal_error (__FILE__, __LINE__, _("frame_unwind_find_by_frame failed"));
+}
+
+/* A default frame sniffer which always accepts the frame.  Used by
+   fallback prologue unwinders.  */
+
+int
+default_frame_sniffer (const struct frame_unwind *self,
+		       struct frame_info *this_frame,
+		       void **this_prologue_cache)
+{
+  return 1;
 }
 
-extern initialize_file_ftype _initialize_frame_unwind; /* -Wmissing-prototypes */
+/* The default frame unwinder stop_reason callback.  */
+
+enum unwind_stop_reason
+default_frame_unwind_stop_reason (struct frame_info *this_frame,
+				  void **this_cache)
+{
+  struct frame_id this_id = get_frame_id (this_frame);
+
+  if (frame_id_eq (this_id, outer_frame_id))
+    return UNWIND_OUTERMOST;
+  else
+    return UNWIND_NO_REASON;
+}
+
+/* See frame-unwind.h.  */
+
+CORE_ADDR
+default_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+  int pc_regnum = gdbarch_pc_regnum (gdbarch);
+  CORE_ADDR pc = frame_unwind_register_unsigned (next_frame, pc_regnum);
+  pc = gdbarch_addr_bits_remove (gdbarch, pc);
+  return pc;
+}
+
+/* See frame-unwind.h.  */
+
+CORE_ADDR
+default_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame)
+{
+  int sp_regnum = gdbarch_sp_regnum (gdbarch);
+  return frame_unwind_register_unsigned (next_frame, sp_regnum);
+}
+
+/* Helper functions for value-based register unwinding.  These return
+   a (possibly lazy) value of the appropriate type.  */
+
+/* Return a value which indicates that FRAME did not save REGNUM.  */
+
+struct value *
+frame_unwind_got_optimized (struct frame_info *frame, int regnum)
+{
+  struct gdbarch *gdbarch = frame_unwind_arch (frame);
+  struct type *type = register_type (gdbarch, regnum);
+  struct value *val;
+
+  /* Return an lval_register value, so that we print it as
+     "<not saved>".  */
+  val = allocate_value_lazy (type);
+  set_value_lazy (val, 0);
+  mark_value_bytes_optimized_out (val, 0, TYPE_LENGTH (type));
+  VALUE_LVAL (val) = lval_register;
+  VALUE_REGNUM (val) = regnum;
+  VALUE_NEXT_FRAME_ID (val)
+    = get_frame_id (get_next_frame_sentinel_okay (frame));
+  return val;
+}
+
+/* Return a value which indicates that FRAME copied REGNUM into
+   register NEW_REGNUM.  */
+
+struct value *
+frame_unwind_got_register (struct frame_info *frame,
+			   int regnum, int new_regnum)
+{
+  return value_of_register_lazy (frame, new_regnum);
+}
+
+/* Return a value which indicates that FRAME saved REGNUM in memory at
+   ADDR.  */
+
+struct value *
+frame_unwind_got_memory (struct frame_info *frame, int regnum, CORE_ADDR addr)
+{
+  struct gdbarch *gdbarch = frame_unwind_arch (frame);
+  struct value *v = value_at_lazy (register_type (gdbarch, regnum), addr);
+
+  set_value_stack (v, 1);
+  return v;
+}
+
+/* Return a value which indicates that FRAME's saved version of
+   REGNUM has a known constant (computed) value of VAL.  */
+
+struct value *
+frame_unwind_got_constant (struct frame_info *frame, int regnum,
+			   ULONGEST val)
+{
+  struct gdbarch *gdbarch = frame_unwind_arch (frame);
+  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
+  struct value *reg_val;
+
+  reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
+  store_unsigned_integer (value_contents_writeable (reg_val),
+			  register_size (gdbarch, regnum), byte_order, val);
+  return reg_val;
+}
+
+struct value *
+frame_unwind_got_bytes (struct frame_info *frame, int regnum, gdb_byte *buf)
+{
+  struct gdbarch *gdbarch = frame_unwind_arch (frame);
+  struct value *reg_val;
+
+  reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
+  memcpy (value_contents_raw (reg_val), buf, register_size (gdbarch, regnum));
+  return reg_val;
+}
+
+/* Return a value which indicates that FRAME's saved version of REGNUM
+   has a known constant (computed) value of ADDR.  Convert the
+   CORE_ADDR to a target address if necessary.  */
+
+struct value *
+frame_unwind_got_address (struct frame_info *frame, int regnum,
+			  CORE_ADDR addr)
+{
+  struct gdbarch *gdbarch = frame_unwind_arch (frame);
+  struct value *reg_val;
+
+  reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
+  pack_long (value_contents_writeable (reg_val),
+	     register_type (gdbarch, regnum), addr);
+  return reg_val;
+}
 
+void _initialize_frame_unwind ();
 void
-_initialize_frame_unwind (void)
+_initialize_frame_unwind ()
 {
   frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init);
 }