Simplify REGISTRY cleanup usages

In registry.c:registry_clear_data, the registered data is iterated and
invoke each 'free' function with the data passed:

  for (registration = data_registry->registrations, i = 0;
       i < fields->num_data;
       registration = registration->next, i++)
    if (fields->data[i] != NULL && registration->data->free != NULL)
      adaptor (registration->data->free, container, fields->data[i]);

we can see that data is passed to function 'free' and data is not NULL.
In each usage, we don't have to get the data again through key and
do NULL pointer checking.  This patch is to simplify them.

gdb:

2013-10-29  Yao Qi  <yao@codesourcery.com>

	* auto-load.c (auto_load_pspace_data_cleanup): Get data from
	parameter 'arg' instead of from program_space_data.
	* objfiles.c (objfiles_pspace_data_cleanup): Likewise.
	* solib-darwin.c (darwin_pspace_data_cleanup): Likewise.
	* solib-dsbt.c (dsbt_pspace_data_cleanup): Likewise.
	* solib-svr4.c (svr4_pspace_data_cleanup): Likewise.
	* inflow.c (inflow_inferior_data_cleanup): Get data from
	parameter 'arg' instead of inferior_data.
	* registry.h: Add comments.

8 files changed, 30 insertions, 39 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8bb0385..d050c23 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,15 @@
+2013-10-29  Yao Qi  <yao@codesourcery.com>
+
+	* auto-load.c (auto_load_pspace_data_cleanup): Get data from
+	parameter 'arg' instead of from program_space_data.
+	* objfiles.c (objfiles_pspace_data_cleanup): Likewise.
+	* solib-darwin.c (darwin_pspace_data_cleanup): Likewise.
+	* solib-dsbt.c (dsbt_pspace_data_cleanup): Likewise.
+	* solib-svr4.c (svr4_pspace_data_cleanup): Likewise.
+	* inflow.c (inflow_inferior_data_cleanup): Get data from
+	parameter 'arg' instead of inferior_data.
+	* registry.h: Add comments.
+
 2013-10-28  Pedro Alves  <palves@redhat.com>
 
 	* breakpoint.c (watchpoints_triggered)
diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index 4eb7cdd..2c534c7 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -572,15 +572,11 @@ static const struct program_space_data *auto_load_pspace_data;
 static void
 auto_load_pspace_data_cleanup (struct program_space *pspace, void *arg)
 {
-  struct auto_load_pspace_info *info;
+  struct auto_load_pspace_info *info = arg;
 
-  info = program_space_data (pspace, auto_load_pspace_data);
-  if (info != NULL)
-    {
-      if (info->loaded_scripts)
-	htab_delete (info->loaded_scripts);
-      xfree (info);
-    }
+  if (info->loaded_scripts)
+    htab_delete (info->loaded_scripts);
+  xfree (info);
 }
 
 /* Get the current autoload data.  If none is found yet, add it now.  This
diff --git a/gdb/inflow.c b/gdb/inflow.c
index f64c0c1..ad73efe 100644
--- a/gdb/inflow.c
+++ b/gdb/inflow.c
@@ -487,15 +487,11 @@ static const struct inferior_data *inflow_inferior_data;
 static void
 inflow_inferior_data_cleanup (struct inferior *inf, void *arg)
 {
-  struct terminal_info *info;
+  struct terminal_info *info = arg;
 
-  info = inferior_data (inf, inflow_inferior_data);
-  if (info != NULL)
-    {
-      xfree (info->run_terminal);
-      xfree (info->ttystate);
-      xfree (info);
-    }
+  xfree (info->run_terminal);
+  xfree (info->ttystate);
+  xfree (info);
 }
 
 /* Get the current svr4 data.  If none is found yet, add it now.  This
diff --git a/gdb/objfiles.c b/gdb/objfiles.c
index d1f3121..7029196 100644
--- a/gdb/objfiles.c
+++ b/gdb/objfiles.c
@@ -85,14 +85,10 @@ static const struct program_space_data *objfiles_pspace_data;
 static void
 objfiles_pspace_data_cleanup (struct program_space *pspace, void *arg)
 {
-  struct objfile_pspace_info *info;
+  struct objfile_pspace_info *info = arg;
 
-  info = program_space_data (pspace, objfiles_pspace_data);
-  if (info != NULL)
-    {
-      xfree (info->sections);
-      xfree (info);
-    }
+  xfree (info->sections);
+  xfree (info);
 }
 
 /* Get the current svr4 data.  If none is found yet, add it now.  This
diff --git a/gdb/registry.h b/gdb/registry.h
index b3d1b55..cb5d0c3 100644
--- a/gdb/registry.h
+++ b/gdb/registry.h
@@ -45,11 +45,12 @@
    
    - register_TAG_data_with_cleanup(TAG, SAVE, FREE)
    Get a new key for the container type TAG.
-   SAVE and FREE are defined as void (*) (struct TAG *, void *)
-   When the container is destroyed, first all registered SAVE
+   SAVE and FREE are defined as void (*) (struct TAG *object, void *data)
+   When the container object OBJECT is destroyed, first all registered SAVE
    functions are called.
    Then all FREE functions are called.
-   Either or both may be NULL.
+   Either or both may be NULL.  DATA is the data associated with the
+   container object OBJECT.
    
    - clear_TAG_data(TAG, OBJECT)
    Clear all the data associated with OBJECT.  Should be called by the
diff --git a/gdb/solib-darwin.c b/gdb/solib-darwin.c
index c4c6308..c37049a 100644
--- a/gdb/solib-darwin.c
+++ b/gdb/solib-darwin.c
@@ -88,10 +88,7 @@ static const struct program_space_data *solib_darwin_pspace_data;
 static void
 darwin_pspace_data_cleanup (struct program_space *pspace, void *arg)
 {
-  struct darwin_info *info;
-
-  info = program_space_data (pspace, solib_darwin_pspace_data);
-  xfree (info);
+  xfree (arg);
 }
 
 /* Get the current darwin data.  If none is found yet, add it now.  This
diff --git a/gdb/solib-dsbt.c b/gdb/solib-dsbt.c
index 4fe24f8..4e2091b 100644
--- a/gdb/solib-dsbt.c
+++ b/gdb/solib-dsbt.c
@@ -166,10 +166,7 @@ static const struct program_space_data *solib_dsbt_pspace_data;
 static void
 dsbt_pspace_data_cleanup (struct program_space *pspace, void *arg)
 {
-  struct dsbt_info *info;
-
-  info = program_space_data (pspace, solib_dsbt_pspace_data);
-  xfree (info);
+  xfree (arg);
 }
 
 /* Get the current dsbt data.  If none is found yet, add it now.  This
diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
index ddbbd94..3eea057 100644
--- a/gdb/solib-svr4.c
+++ b/gdb/solib-svr4.c
@@ -407,11 +407,7 @@ free_solib_list (struct svr4_info *info)
 static void
 svr4_pspace_data_cleanup (struct program_space *pspace, void *arg)
 {
-  struct svr4_info *info;
-
-  info = program_space_data (pspace, solib_svr4_pspace_data);
-  if (info == NULL)
-    return;
+  struct svr4_info *info = arg;
 
   free_probes_table (info);
   free_solib_list (info);