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=aaf950a1fde7a4fda269b852fba51d41c3c7fb17;hpb=1c5465ac6061382a64975cbe2e619054bfc71c45;p=deliverable%2Fbinutils-gdb.git

diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c
index aaf950a1fd..3334c472d0 100644
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -1,7 +1,6 @@
 /* Definitions for frame unwinder, for GDB, the GNU debugger.
 
-   Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010
-   Free Software Foundation, Inc.
+   Copyright (C) 2003-2020 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -25,9 +24,10 @@
 #include "inline-frame.h"
 #include "value.h"
 #include "regcache.h"
-
-#include "gdb_assert.h"
 #include "gdb_obstack.h"
+#include "target.h"
+#include "gdbarch.h"
+#include "dwarf2/frame-tailcall.h"
 
 static struct gdbarch_data *frame_unwind_data;
 
@@ -44,19 +44,41 @@ struct frame_unwind_table
   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);
+
   /* Start the table out with a few default sniffers.  OSABI code
      can't override this.  */
-  table->list = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
-  table->list->unwinder = dummy_frame_unwind;
-  table->list->next = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry);
-  table->list->next->unwinder = inline_frame_unwind;
+  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 = &table->list->next->next;
+  table->osabi_head = link;
   return table;
 }
 
@@ -64,7 +86,8 @@ void
 frame_unwind_prepend_unwinder (struct gdbarch *gdbarch,
 				const struct frame_unwind *unwinder)
 {
-  struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
+  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.  */
@@ -78,7 +101,8 @@ void
 frame_unwind_append_unwinder (struct gdbarch *gdbarch,
 			      const struct frame_unwind *unwinder)
 {
-  struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
+  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.  */
@@ -87,26 +111,81 @@ frame_unwind_append_unwinder (struct gdbarch *gdbarch,
   (*ip)->unwinder = unwinder;
 }
 
-const struct frame_unwind *
-frame_unwind_find_by_frame (struct frame_info *this_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)
 {
-  struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  struct frame_unwind_table *table = gdbarch_data (gdbarch, frame_unwind_data);
-  struct frame_unwind_table_entry *entry;
+  int res = 0;
 
-  for (entry = table->list; entry != NULL; entry = entry->next)
+  frame_prepare_for_sniffer (this_frame, unwinder);
+
+  try
+    {
+      res = unwinder->sniffer (unwinder, this_frame, this_cache);
+    }
+  catch (const gdb_exception &ex)
     {
-      struct cleanup *old_cleanup;
+      /* Catch all exceptions, caused by either interrupt or error.
+	 Reset *THIS_CACHE.  */
+      *this_cache = NULL;
+      frame_cleanup_after_sniffer (this_frame);
 
-      old_cleanup = frame_prepare_for_sniffer (this_frame, entry->unwinder);
-      if (entry->unwinder->sniffer (entry->unwinder, this_frame,
-				    this_cache))
+      if (ex.error == NOT_AVAILABLE_ERROR)
 	{
-	  discard_cleanups (old_cleanup);
-	  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;
 	}
-      do_cleanups (old_cleanup);
+      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;
     }
+  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"));
 }
 
@@ -121,6 +200,40 @@ default_frame_sniffer (const struct frame_unwind *self,
   return 1;
 }
 
+/* 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.  */
 
@@ -130,18 +243,27 @@ struct value *
 frame_unwind_got_optimized (struct frame_info *frame, int regnum)
 {
   struct gdbarch *gdbarch = frame_unwind_arch (frame);
-  struct value *reg_val;
-
-  reg_val = value_zero (register_type (gdbarch, regnum), not_lval);
-  set_value_optimized_out (reg_val, 1);
-  return reg_val;
+  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)
+frame_unwind_got_register (struct frame_info *frame,
+			   int regnum, int new_regnum)
 {
   return value_of_register_lazy (frame, new_regnum);
 }
@@ -204,10 +326,9 @@ frame_unwind_got_address (struct frame_info *frame, int regnum,
   return reg_val;
 }
 
-extern initialize_file_ftype _initialize_frame_unwind; /* -Wmissing-prototypes */
-
+void _initialize_frame_unwind ();
 void
-_initialize_frame_unwind (void)
+_initialize_frame_unwind ()
 {
   frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init);
 }