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.

2 files changed, 28 insertions, 2 deletions

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