gdb: make frame_info_ptr auto-reinflatable

This is the second step of making frame_info_ptr automatic, reinflate on
demand whenever trying to obtain the wrapper frame_info pointer, either
through the get method or operator->.  Make the reinflate method
private, it is used as a convenience method in those two.

Add an "is_null" method, because it is often needed to know whether the
frame_info_ptr wraps an frame_info or is empty.

Make m_ptr mutable, so that it's possible to reinflate const
frame_info_ptr objects.  Whether m_ptr is nullptr or not does not change
the logical state of the object, because we re-create it on demand.  I
believe this is the right use case for mutable.

Change-Id: Icb0552d0035e227f81eb3c121d8a9bb2f9d25794
Reviewed-By: Bruno Larsen <blarsen@redhat.com>

diff --git a/gdb/frame.c b/gdb/frame.c
index c4b0f0166d69d96abb2de7c8b44271f1494061c2..a08a8f47ebc4142d016dde6acc206703f76da034 100644 (file)
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -3224,8 +3224,8 @@ frame_info_ptr::frame_info_ptr (struct frame_info *ptr)
 
 /* See frame-info-ptr.h.  */
 
-void
-frame_info_ptr::reinflate ()
+frame_info *
+frame_info_ptr::reinflate () const
 {
   /* Ensure we have a valid frame level (sentinel frame or above).  */
   gdb_assert (m_cached_level >= -1);
@@ -3233,7 +3233,7 @@ frame_info_ptr::reinflate ()
   if (m_ptr != nullptr)
     {
       /* The frame_info wasn't invalidated, no need to reinflate.  */
-      return;
+      return m_ptr;
     }
 
   if (m_cached_id.user_created_p)
@@ -3255,6 +3255,7 @@ frame_info_ptr::reinflate ()
     }
 
   gdb_assert (m_ptr != nullptr);
+  return m_ptr;
 }
 
 void _initialize_frame ();

diff --git a/gdb/frame.h b/gdb/frame.h
index 105b9fb92a8bf6b828915634f880ffaec4a4b584..c4f7c121391bf12068c6b11855d183a71686e699 100644 (file)
--- a/gdb/frame.h
+++ b/gdb/frame.h
@@ -275,29 +275,38 @@ public:
   }
 
   frame_info *operator-> () const
-  {
-    return m_ptr;
-  }
+  { return this->reinflate (); }
 
   /* Fetch the underlying pointer.  Note that new code should
      generally not use this -- avoid it if at all possible.  */
   frame_info *get () const
   {
-    return m_ptr;
+    if (this->is_null ())
+      return nullptr;
+
+    return this->reinflate ();
   }
 
+  /* Return true if this object is empty (does not wrap a frame_info
+     object).  */
+
+  bool is_null () const
+  {
+    return m_cached_level == this->invalid_level;
+  };
+
   /* This exists for compatibility with pre-existing code that checked
      a "frame_info *" using "!".  */
   bool operator! () const
   {
-    return m_ptr == nullptr;
+    return this->is_null ();
   }
 
   /* This exists for compatibility with pre-existing code that checked
      a "frame_info *" like "if (ptr)".  */
   explicit operator bool () const
   {
-    return m_ptr != nullptr;
+    return !this->is_null ();
   }
 
   /* Invalidate this pointer.  */
@@ -306,17 +315,18 @@ public:
     m_ptr = nullptr;
   }
 
-  /* Use the cached frame_id to reinflate the pointer.  */
-  void reinflate ();
-
 private:
   /* We sometimes need to construct frame_info_ptr objects around the
      sentinel_frame, which has level -1.  Therefore, make the invalid frame
      level value -2.  */
   static constexpr int invalid_level = -2;
 
+  /* Use the cached frame level and id to reinflate the pointer, and return
+     it.  */
+  frame_info *reinflate () const;
+
   /* The underlying pointer.  */
-  frame_info *m_ptr = nullptr;
+  mutable frame_info *m_ptr = nullptr;
 
   /* The frame_id of the underlying pointer.
 
@@ -341,37 +351,46 @@ private:
 static inline bool
 operator== (const frame_info *self, const frame_info_ptr &other)
 {
+  if (self == nullptr || other.is_null ())
+    return self == nullptr && other.is_null ();
+
   return self == other.get ();
 }
 
 static inline bool
 operator== (const frame_info_ptr &self, const frame_info_ptr &other)
 {
+  if (self.is_null () || other.is_null ())
+    return self.is_null () && other.is_null ();
+
   return self.get () == other.get ();
 }
 
 static inline bool
 operator== (const frame_info_ptr &self, const frame_info *other)
 {
+  if (self.is_null () || other == nullptr)
+    return self.is_null () && other == nullptr;
+
   return self.get () == other;
 }
 
 static inline bool
 operator!= (const frame_info *self, const frame_info_ptr &other)
 {
-  return self != other.get ();
+  return !(self == other);
 }
 
 static inline bool
 operator!= (const frame_info_ptr &self, const frame_info_ptr &other)
 {
-  return self.get () != other.get ();
+  return !(self == other);
 }
 
 static inline bool
 operator!= (const frame_info_ptr &self, const frame_info *other)
 {
-  return self.get () != other;
+  return !(self == other);
 }
 
 /* For every stopped thread, GDB tracks two frames: current and

diff --git a/gdb/infcall.c b/gdb/infcall.c
index a60cca47c33b477ef047a3fd39cf2676325b656b..4c2a4e4f4003f7b29b75e78857dd4941274ac7be 100644 (file)
--- a/gdb/infcall.c
+++ b/gdb/infcall.c
@@ -857,8 +857,6 @@ call_function_by_hand_dummy (struct value *function,
             "target calling convention."),
           get_function_name (funaddr, name_buf, sizeof (name_buf)));
 
-  frame.reinflate ();
-
   if (values_type == NULL || values_type->is_stub ())
     values_type = default_return_type;
   if (values_type == NULL)

diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index 15dca8c4604d0a15e21d2fb993bc23104dc37c2f..fd88b8ca32815b96052a993a1a67f9a1ada5ec12 100644 (file)
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -1915,7 +1915,6 @@ finish_command (const char *arg, int from_tty)
 
       print_stack_frame (callee_frame, 1, LOCATION, 0);
     }
-  frame.reinflate ();
 
   if (execution_direction == EXEC_REVERSE)
     finish_backward (sm);

diff --git a/gdb/mi/mi-cmd-stack.c b/gdb/mi/mi-cmd-stack.c
index 9582fa24507bb4cf00b12165e0a38a59463c077c..00e61e04b678fd1b7fe91228abbfc457dedfc659 100644 (file)
--- a/gdb/mi/mi-cmd-stack.c
+++ b/gdb/mi/mi-cmd-stack.c
@@ -180,7 +180,6 @@ mi_cmd_stack_list_frames (const char *command, char **argv, int argc)
             If args is 0, don't print the arguments.  */
          print_frame_info (user_frame_print_options,
                            fi, 1, LOC_AND_ADDRESS, 0 /* args */, 0);
-         fi.reinflate ();
        }
     }
 }

diff --git a/gdb/stack.c b/gdb/stack.c
index 4250383d9ebb266bffb0d6b04642f33ce1d30a8b..c36f144f093a428e815d01d892698aa2a2e993cc 100644 (file)
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -367,7 +367,6 @@ print_stack_frame (frame_info_ptr frame, int print_level,
       print_frame_info (user_frame_print_options,
                        frame, print_level, print_what, 1 /* print_args */,
                        set_current_sal);
-      frame.reinflate ();
       if (set_current_sal)
        set_current_sal_from_frame (frame);
     }
@@ -903,7 +902,6 @@ print_frame_args (const frame_print_options &fp_opts,
            }
 
          first = 0;
-         frame.reinflate ();
        }
     }
 
@@ -1173,7 +1171,6 @@ print_frame_info (const frame_print_options &fp_opts,
 
          print_source_lines (sal.symtab, sal.line, sal.line + 1, 0);
        }
-      frame.reinflate ();
 
       /* If disassemble-next-line is set to on and there is line debug
         messages, output assembly codes for next line.  */
@@ -1676,8 +1673,6 @@ info_frame_command_core (frame_info_ptr fi, bool selected_frame_p)
 
        print_frame_args (user_frame_print_options,
                          func, fi, numargs, gdb_stdout);
-       fi.reinflate ();
-
        gdb_puts ("\n");
       }
   }
@@ -2077,7 +2072,6 @@ backtrace_command_1 (const frame_print_options &fp_opts,
            print_frame_local_vars (fi, false, NULL, NULL, 1, gdb_stdout);
 
          /* Save the last frame to check for error conditions.  */
-         fi.reinflate ();
          trailing = fi;
        }
 

diff --git a/gdb/unittests/frame_info_ptr-selftests.c b/gdb/unittests/frame_info_ptr-selftests.c
index 47306113c7aaaa8ab30b7f12e47fd52aeb69e66e..fe1e7be35daab81acdc2e127028af0013c0ce77f 100644 (file)
--- a/gdb/unittests/frame_info_ptr-selftests.c
+++ b/gdb/unittests/frame_info_ptr-selftests.c
@@ -41,7 +41,6 @@ user_created_frame_callee (frame_info_ptr frame)
   validate_user_created_frame (get_frame_id (frame));
 
   reinit_frame_cache ();
-  frame.reinflate ();
 
   validate_user_created_frame (get_frame_id (frame));
 
@@ -61,7 +60,6 @@ test_user_created_frame ()
      validate that the reinflation in both the callee and caller restore the
      same frame_info object.  */
   frame_info_ptr callees_frame_info = user_created_frame_callee (frame);
-  frame.reinflate ();
 
   validate_user_created_frame (get_frame_id (frame));
   SELF_CHECK (frame.get () == callees_frame_info.get ());