Fix bug with character enumeration literal

gnat encodes character enumeration literals using a few different
schemes.  The gnat compiler documented the "QU" and "QW" encodings,
but failed to document that a simpler encoding was used for certain
characters.

This patch updates gdb to handle this simple Q encoding.  Note that
wide character literals are still not handled.

gdb/ChangeLog
2019-08-15  Tom Tromey  <tromey@adacore.com>

	* ada-exp.y (convert_char_literal): Handle "Q%c" encoding.
	* ada-lang.c (ada_enum_name): Likewise.

gdb/testsuite/ChangeLog
2019-08-15  Tom Tromey  <tromey@adacore.com>

	* gdb.ada/char_enum.exp: Add regression tests.
	* gdb.ada/char_enum/foo.adb (Char_Enum_Type): Use '_'
	and '0'.
	(Char, Gchar): Update.
	* gdb.ada/char_enum/pck.ads (Global_Enum_Type): Use '+'.

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2019-08-15  Tom Tromey  <tromey@adacore.com>
+
+	* ada-exp.y (convert_char_literal): Handle "Q%c" encoding.
+	* ada-lang.c (ada_enum_name): Likewise.
+
 2019-08-15  Christian Biesinger  <cbiesinger@google.com>
 
 	* python/lib/gdb/__init__.py (GdbOutputFile): Rename to have a

gdb/ada-exp.y

@@ -1390,7 +1390,10 @@ convert_char_literal (struct type *type, LONGEST val)
   if (TYPE_CODE (type) != TYPE_CODE_ENUM)
     return val;
 
-  xsnprintf (name, sizeof (name), "QU%02x", (int) val);
+  if ((val >= 'a' && val <= 'z') || (val >= '0' && val <= '9'))
+    xsnprintf (name, sizeof (name), "Q%c", (int) val);
+  else
+    xsnprintf (name, sizeof (name), "QU%02x", (int) val);
   size_t len = strlen (name);
   for (f = 0; f < TYPE_NFIELDS (type); f += 1)
     {

gdb/ada-lang.c

@@ -9439,6 +9439,14 @@ ada_enum_name (const char *name)
           if (sscanf (name + 2, "%x", &v) != 1)
             return name;
         }
+      else if (((name[1] >= '0' && name[1] <= '9')
+		|| (name[1] >= 'a' && name[1] <= 'z'))
+	       && name[2] == '\0')
+	{
+	  GROW_VECT (result, result_len, 4);
+	  xsnprintf (result, result_len, "'%c'", name[1]);
+	  return result;
+	}
       else
         return name;
 

gdb/testsuite/ChangeLog

@@ -1,3 +1,11 @@
+2019-08-15  Tom Tromey  <tromey@adacore.com>
+
+	* gdb.ada/char_enum.exp: Add regression tests.
+	* gdb.ada/char_enum/foo.adb (Char_Enum_Type): Use '_'
+	and '0'.
+	(Char, Gchar): Update.
+	* gdb.ada/char_enum/pck.ads (Global_Enum_Type): Use '+'.
+
 2019-08-15  Christian Biesinger  <cbiesinger@google.com>
 
 	* gdb.python/python.exp: Expect a leading underscore on

gdb/testsuite/gdb.ada/char_enum.exp

@@ -26,5 +26,11 @@ clean_restart ${testfile}
 set bp_location [gdb_get_line_number "STOP" ${testdir}/foo.adb]
 runto "foo.adb:$bp_location"
 
+gdb_test "ptype Char_Enum_Type" "type = \\('A', 'B', 'C', '_', '0'\\)"
 gdb_test "print Char_Enum_Type'('B')" "= 1 'B'"
+gdb_test "print Char_Enum_Type'('_')" "= 3 '_'"
+gdb_test "print Char_Enum_Type'('0')" "= 4 '0'"
+gdb_test "ptype pck.Global_Enum_Type" "type = \\('x', 'Y', '\\+'\\)"
+gdb_test "print pck.Global_Enum_Type'('x')" "= 0 'x'"
 gdb_test "print pck.Global_Enum_Type'('Y')" "= 1 'Y'"
+gdb_test "print pck.Global_Enum_Type'('+')" "= 2 '\\+'"

gdb/testsuite/gdb.ada/char_enum/foo.adb

@@ -16,9 +16,9 @@
 with Pck; use Pck;
 
 procedure Foo is
-   type Char_Enum_Type is ('A', 'B', 'C', 'D', 'E');
-   Char : Char_Enum_Type := 'D';
-   Gchar : Global_Enum_Type := 'Z';
+   type Char_Enum_Type is ('A', 'B', 'C', '_', '0');
+   Char : Char_Enum_Type := '_';
+   Gchar : Global_Enum_Type := '+';
 begin
    Do_Nothing (Char'Address);  -- STOP
 end Foo;

gdb/testsuite/gdb.ada/char_enum/pck.ads

@@ -16,7 +16,7 @@
 with System;
 
 package Pck is
-   type Global_Enum_Type is ('X', 'Y', 'Z');
+   type Global_Enum_Type is ('x', 'Y', '+');
    procedure Do_Nothing (A : System.Address);
 end Pck;