gdb: add target_ops::supports_displaced_step

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

diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c
index 66a28ae1c9cdadbf98412869423688a81354f2d3..3334c472d0202b546f5eea17e27ec6cbbabc7476 100644 (file)
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -1,6 +1,6 @@
 /* Definitions for frame unwinder, for GDB, the GNU debugger.
 
-   Copyright (C) 2003-2018 Free Software Foundation, Inc.
+   Copyright (C) 2003-2020 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -26,6 +26,8 @@
 #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;
 
@@ -42,6 +44,18 @@ 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)
 {
@@ -50,13 +64,21 @@ frame_unwind_init (struct obstack *obstack)
 
   /* 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;
 }
 
@@ -101,27 +123,27 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
 
   frame_prepare_for_sniffer (this_frame, unwinder);
 
-  TRY
+  try
     {
       res = unwinder->sniffer (unwinder, this_frame, this_cache);
     }
-  CATCH (ex, RETURN_MASK_ALL)
+  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)
        {
          /* 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.  */
-         frame_cleanup_after_sniffer (this_frame);
          return 0;
        }
-      throw_exception (ex);
+      throw;
     }
-  END_CATCH
 
   if (res)
     return 1;
@@ -192,6 +214,26 @@ default_frame_unwind_stop_reason (struct frame_info *this_frame,
     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.  */
 
@@ -284,8 +326,9 @@ frame_unwind_got_address (struct frame_info *frame, int regnum,
   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);
 }