gdb: Remove casts of NULL during assignment.

In the following code:

    struct symbol *wsym = (struct symbol *) NULL;

the cast of NULL is redundant, it adds noise, and is just one more thing
to change if the type of wsym ever changes.  There are a relatively
small number of places in gdb where the above code pattern is used.
Usually the cast is removed like this:

    struct symbol *wsym = NULL;

This commit updates all the places within the gdb/ directory where we
cast NULL during assignment, removing the cast.

gdb/ChangeLog:

	* c-valprint.c (print_unpacked_pointer): Remove cast of NULL
	pointer.
	* dbxread.c (dbx_end_psymtab): Likewise.
	* gnu-nat.c (gnu_write_inferior): Likewise.
	* mdebugread.c (cross_ref): Likewise.
	* p-valprint.c (pascal_val_print): Likewise.
	* xcoffread.c (xcoff_end_psymtab): Likewise.

7 files changed, 18 insertions, 8 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index a4474abde36..2ae453f6162 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2015-09-04  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* c-valprint.c (print_unpacked_pointer): Remove cast of NULL
+	pointer.
+	* dbxread.c (dbx_end_psymtab): Likewise.
+	* gnu-nat.c (gnu_write_inferior): Likewise.
+	* mdebugread.c (cross_ref): Likewise.
+	* p-valprint.c (pascal_val_print): Likewise.
+	* xcoffread.c (xcoff_end_psymtab): Likewise.
+
 2015-09-04  Yao Qi  <yao.qi@linaro.org>
 
 	* NEWS: Mention the aarch64 multi-arch debugging support.
diff --git a/gdb/c-valprint.c b/gdb/c-valprint.c
index 80a75d79db1..9c96df2002b 100644
--- a/gdb/c-valprint.c
+++ b/gdb/c-valprint.c
@@ -193,9 +193,9 @@ print_unpacked_pointer (struct type *type, struct type *elttype,
       if (vt_address && options->vtblprint)
 	{
 	  struct value *vt_val;
-	  struct symbol *wsym = (struct symbol *) NULL;
+	  struct symbol *wsym = NULL;
 	  struct type *wtype;
-	  struct block *block = (struct block *) NULL;
+	  struct block *block = NULL;
 	  struct field_of_this_result is_this_fld;
 
 	  if (want_space)
diff --git a/gdb/dbxread.c b/gdb/dbxread.c
index 029b98e38cf..dd81ec8c49e 100644
--- a/gdb/dbxread.c
+++ b/gdb/dbxread.c
@@ -2341,7 +2341,7 @@ dbx_end_psymtab (struct objfile *objfile, struct partial_symtab *pst,
       discard_psymtab (objfile, pst);
 
       /* Indicate that psymtab was thrown away.  */
-      pst = (struct partial_symtab *) NULL;
+      pst = NULL;
     }
   return pst;
 }
diff --git a/gdb/gnu-nat.c b/gdb/gnu-nat.c
index c2dfe5d9b6d..d3f54d0375d 100644
--- a/gdb/gnu-nat.c
+++ b/gdb/gnu-nat.c
@@ -2350,7 +2350,7 @@ gnu_write_inferior (task_t task, CORE_ADDR addr,
   char *errstr = "Bug in gnu_write_inferior";
 
   struct vm_region_list *region_element;
-  struct vm_region_list *region_head = (struct vm_region_list *) NULL;
+  struct vm_region_list *region_head = NULL;
 
   /* Get memory from inferior with page aligned addresses.  */
   err = vm_read (task,
diff --git a/gdb/mdebugread.c b/gdb/mdebugread.c
index 1e684328054..f8338f418bf 100644
--- a/gdb/mdebugread.c
+++ b/gdb/mdebugread.c
@@ -4376,7 +4376,7 @@ cross_ref (int fd, union aux_ext *ax, struct type **tpp,
   int xref_fd;
   struct mdebug_pending *pend;
 
-  *tpp = (struct type *) NULL;
+  *tpp = NULL;
 
   (*debug_swap->swap_rndx_in) (bigend, &ax->a_rndx, rn);
 
diff --git a/gdb/p-valprint.c b/gdb/p-valprint.c
index a0b99f83504..0ceddd1faa3 100644
--- a/gdb/p-valprint.c
+++ b/gdb/p-valprint.c
@@ -239,9 +239,9 @@ pascal_val_print (struct type *type, const gdb_byte *valaddr,
 	  if (vt_address && options->vtblprint)
 	    {
 	      struct value *vt_val;
-	      struct symbol *wsym = (struct symbol *) NULL;
+	      struct symbol *wsym = NULL;
 	      struct type *wtype;
-	      struct block *block = (struct block *) NULL;
+	      struct block *block = NULL;
 	      struct field_of_this_result is_this_fld;
 
 	      if (want_space)
diff --git a/gdb/xcoffread.c b/gdb/xcoffread.c
index 46958013549..0d497514cd9 100644
--- a/gdb/xcoffread.c
+++ b/gdb/xcoffread.c
@@ -2108,7 +2108,7 @@ xcoff_end_psymtab (struct objfile *objfile, struct partial_symtab *pst,
       discard_psymtab (objfile, pst);
 
       /* Indicate that psymtab was thrown away.  */
-      pst = (struct partial_symtab *) NULL;
+      pst = NULL;
     }
   return pst;
 }