varobj zero-padded hexadecimal format

This set of patches add support for the zero-padded hexadecimal format for
varobj's, defined as "zero-hexadecimal".  We currently only support regular
non-zero-padded hexadecimal.

Talking with IDE developers, they would like to have this option that is
already available to GDB's print/x commands, in the CLI, as 'z'.

gdb/ChangeLog:

2015-12-09  Luis Machado  <lgustavo@codesourcery.com>

	* gdb/mi/mi-cmd-var.c (mi_parse_format): Handle new "zero-hexadecimal"
	format.
	* gdb/varobj.c (varobj_format_string): Add "zero-hexadecimal" entry.
	(format_code): Add 'z' entry.
	(varobj_set_display_format): Handle FORMAT_ZHEXADECIMAL.
	* gdb/varobj.h (varobj_display_formats) <FORMAT_ZHEXADECIMAL>: New enum
	field.
	* NEWS: Add new note to MI changes citing the new zero-hexadecimal
	format for -var-set-format.

gdb/doc/ChangeLog:

2015-12-09  Luis Machado  <lgustavo@codesourcery.com>

	* gdb.texinfo (GDB/MI Variable Objects): Update text to mention
	-var-set-format's new zero-hexadecimal format.

gdb/testsuite/ChangeLog:

2015-12-09  Luis Machado  <lgustavo@codesourcery.com>

	* gdb.mi/mi-var-display.exp: Add new checks for the zero-hexadecimal
	  format and change test names to make them unique.

9 files changed, 65 insertions, 7 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 8a8202c..bafae52 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,15 @@
+2015-12-09  Luis Machado  <lgustavo@codesourcery.com>
+
+	* gdb/mi/mi-cmd-var.c (mi_parse_format): Handle new "zero-hexadecimal"
+	format.
+	* gdb/varobj.c (varobj_format_string): Add "zero-hexadecimal" entry.
+	(format_code): Add 'z' entry.
+	(varobj_set_display_format): Handle FORMAT_ZHEXADECIMAL.
+	* gdb/varobj.h (varobj_display_formats) <FORMAT_ZHEXADECIMAL>: New enum
+	field.
+	* NEWS: Add new note to MI changes citing the new zero-hexadecimal
+	format for -var-set-format.
+
 2015-12-09  Ruslan Kabatsayev  <b7.10110111@gmail.com>  (tiny patch)
 
 	PR gdb/18702
diff --git a/gdb/NEWS b/gdb/NEWS
index 280c8fe..9ca7f49 100644
--- a/gdb/NEWS
+++ b/gdb/NEWS
@@ -135,6 +135,12 @@ show remote exec-event-feature-packet
    The reply to qXfer:threads:read may now include a name attribute for each
    thread.
 
+* MI changes
+
+  ** The -var-set-format command now accepts the zero-hexadecimal
+     format.  It outputs data in hexadecimal format with zero-padding on the
+     left.
+
 *** Changes in GDB 7.10
 
 * Support for process record-replay and reverse debugging on aarch64*-linux*
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 6f05e36..7b0dc35 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,3 +1,8 @@
+2015-12-09  Luis Machado  <lgustavo@codesourcery.com>
+
+	* gdb.texinfo (GDB/MI Variable Objects): Update text to mention
+	-var-set-format's new zero-hexadecimal format.
+
 2015-12-08  Pierre-Marie de Rodat  <derodat@adacore.com>
 
 	* gdb.texinfo (Ada Mode Into): Move overloading support
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 9f72c52..be39f1c 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -28980,13 +28980,18 @@ The syntax for the @var{format-spec} is as follows:
 
 @smallexample
  @var{format-spec} @expansion{}
- @{binary | decimal | hexadecimal | octal | natural@}
+ @{binary | decimal | hexadecimal | octal | natural | zero-hexadecimal@}
 @end smallexample
 
 The natural format is the default format choosen automatically
 based on the variable type (like decimal for an @code{int}, hex
 for pointers, etc.).
 
+The zero-hexadecimal format has a representation similar to hexadecimal
+but with padding zeroes to the left of the value.  For example, a 32-bit
+hexadecimal value of 0x1234 would be represented as 0x00001234 in the
+zero-hexadecimal format.
+
 For a variable with children, the format is set only on the 
 variable itself, and the children are not affected.  
 
diff --git a/gdb/mi/mi-cmd-var.c b/gdb/mi/mi-cmd-var.c
index e316812..643fd7a 100644
--- a/gdb/mi/mi-cmd-var.c
+++ b/gdb/mi/mi-cmd-var.c
@@ -233,10 +233,12 @@ mi_parse_format (const char *arg)
 	return FORMAT_HEXADECIMAL;
       else if (strncmp (arg, "octal", len) == 0)
 	return FORMAT_OCTAL;
+      else if (strncmp (arg, "zero-hexadecimal", len) == 0)
+	return FORMAT_ZHEXADECIMAL;
     }
 
   error (_("Must specify the format as: \"natural\", "
-	   "\"binary\", \"decimal\", \"hexadecimal\", or \"octal\""));
+	   "\"binary\", \"decimal\", \"hexadecimal\", \"octal\" or \"zero-hexadecimal\""));
 }
 
 void
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index d959e7b..e4b396f 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-12-09  Luis Machado  <lgustavo@codesourcery.com>
+
+	* gdb.mi/mi-var-display.exp: Add new checks for the zero-hexadecimal
+	  format and change test names to make them unique.
+
 2015-12-09  Ruslan Kabatsayev  <b7.10110111@gmail.com>
 	    Pedro Alves  <pedro@redhat.com>
 
diff --git a/gdb/testsuite/gdb.mi/mi-var-display.exp b/gdb/testsuite/gdb.mi/mi-var-display.exp
index 31bdce4..d65233b 100644
--- a/gdb/testsuite/gdb.mi/mi-var-display.exp
+++ b/gdb/testsuite/gdb.mi/mi-var-display.exp
@@ -81,6 +81,11 @@ mi_gdb_test "-var-evaluate-expression bar" \
 	"eval variable bar"
 
 # Test: c_variable-6.5
+# Desc: change format of bar to zero-padded hexadecimal
+mi_gdb_test "-var-set-format bar zero-hexadecimal" \
+	"\\^done,format=\"zero-hexadecimal\",value=\"0x0.*849\"" \
+	"set format variable bar in zero-padded hexadecimal"
+
 # Desc: change format of bar to hex
 mi_gdb_test "-var-set-format bar hexadecimal" \
 	"\\^done,format=\"hexadecimal\",value=\"0x849\"" \
@@ -241,7 +246,7 @@ mi_gdb_test "-var-set-format weird.func_ptr hexadecimal" \
 
 mi_gdb_test "-var-show-format weird.func_ptr" \
 	"\\^done,format=\"hexadecimal\"" \
-	"show format variable weird.func_ptr"
+	"show format variable weird.func_ptr (hex)"
 
 mi_gdb_test "-var-set-format weird.func_ptr_ptr hexadecimal" \
 	"\\^done,format=\"hexadecimal\",value=\"$hex\"" \
@@ -249,7 +254,23 @@ mi_gdb_test "-var-set-format weird.func_ptr_ptr hexadecimal" \
 
 mi_gdb_test "-var-show-format weird.func_ptr_ptr" \
 	"\\^done,format=\"hexadecimal\"" \
-	"show format variable weird.func_ptr_ptr"
+	"show format variable weird.func_ptr_ptr (hex)"
+
+mi_gdb_test "-var-set-format weird.func_ptr zero-hexadecimal" \
+	"\\^done,format=\"zero-hexadecimal\",value=\"$hex\"" \
+	"set format variable weird.func_ptr in zero-padded hex"
+
+mi_gdb_test "-var-show-format weird.func_ptr" \
+	"\\^done,format=\"zero-hexadecimal\"" \
+	"show format variable weird.func_ptr (zhex)"
+
+mi_gdb_test "-var-set-format weird.func_ptr_ptr zero-hexadecimal" \
+	"\\^done,format=\"zero-hexadecimal\",value=\"$hex\"" \
+	"set format variable weird.func_ptr_ptr in zero-padded hex"
+
+mi_gdb_test "-var-show-format weird.func_ptr_ptr" \
+	"\\^done,format=\"zero-hexadecimal\"" \
+	"show format variable weird.func_ptr_ptr (zhex)"
 
 # Test: c_variable-6.24
 # Desc: format of weird and children
diff --git a/gdb/varobj.c b/gdb/varobj.c
index 92b0f33..0b19d84 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -50,7 +50,7 @@ show_varobjdebug (struct ui_file *file, int from_tty,
 
 /* String representations of gdb's format codes.  */
 char *varobj_format_string[] =
-  { "natural", "binary", "decimal", "hexadecimal", "octal" };
+  { "natural", "binary", "decimal", "hexadecimal", "octal", "zero-hexadecimal" };
 
 /* True if we want to allow Python-based pretty-printing.  */
 static int pretty_printing = 0;
@@ -214,7 +214,7 @@ static struct varobj *varobj_add_child (struct varobj *var,
 /* Private data */
 
 /* Mappings of varobj_display_formats enums to gdb's format codes.  */
-static int format_code[] = { 0, 't', 'd', 'x', 'o' };
+static int format_code[] = { 0, 't', 'd', 'x', 'o', 'z' };
 
 /* Header of the list of root variable objects.  */
 static struct varobj_root *rootlist;
@@ -583,6 +583,7 @@ varobj_set_display_format (struct varobj *var,
     case FORMAT_DECIMAL:
     case FORMAT_HEXADECIMAL:
     case FORMAT_OCTAL:
+    case FORMAT_ZHEXADECIMAL:
       var->format = format;
       break;
 
diff --git a/gdb/varobj.h b/gdb/varobj.h
index 8860526..179b2a5 100644
--- a/gdb/varobj.h
+++ b/gdb/varobj.h
@@ -28,7 +28,8 @@ enum varobj_display_formats
     FORMAT_BINARY,		/* Binary display                    */
     FORMAT_DECIMAL,		/* Decimal display                   */
     FORMAT_HEXADECIMAL,		/* Hex display                       */
-    FORMAT_OCTAL		/* Octal display                     */
+    FORMAT_OCTAL,		/* Octal display                     */
+    FORMAT_ZHEXADECIMAL		/* Zero padded hexadecimal	     */
   };
 
 enum varobj_type