gdb: fix debug dump of OP_BOOL expressions

Consider this GDB session:

  (gdb) set language fortran
  (gdb) set debug expression 1
  (gdb) p .TRUE.
  Dump of expression @ 0x4055d90, before conversion to prefix form:
  	Language fortran, 3 elements, 16 bytes each.
  	Index                Opcode         Hex Value  String Value
  	    0               OP_BOOL  79  O...............
  	    1             BINOP_ADD  1  ................
  	    2               OP_BOOL  79  O...............
  Dump of expression @ 0x4055d90, after conversion to prefix form:
  Expression: `TRUE'
  	Language fortran, 3 elements, 16 bytes each.

  	    0  OP_BOOL               Unknown format
  	    1  BINOP_ADD
  	    2    OP_BOOL               Unknown format
  	    3    OP_NULL               Unknown format
  $1 = .TRUE.

The final dump of the OP_BOOL is completely wrong.  After this patch
we now get:

  (gdb) set language fortran
  (gdb) set debug expression 1
  (gdb) p .TRUE.
  Dump of expression @ 0x2d07470, before conversion to prefix form:
  	Language fortran, 3 elements, 16 bytes each.
  	Index                Opcode         Hex Value  String Value
  	    0               OP_BOOL  79  O...............
  	    1             BINOP_ADD  1  ................
  	    2               OP_BOOL  79  O...............
  Dump of expression @ 0x2d07470, after conversion to prefix form:
  Expression: `TRUE'
  	Language fortran, 3 elements, 16 bytes each.

  	    0  OP_BOOL               TRUE
  $1 = .TRUE.

Much better.  I added a test for this into the Fortran testsuite.

gdb/ChangeLog:

	* expprint.c (dump_subexp_body_standard): Handle OP_BOOL.

gdb/testsuite/ChangeLog:

	* gdb.fortran/debug-expr.exp: Add new tests.

gdb/ChangeLog

@@ -1,3 +1,7 @@
+2021-01-12  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* expprint.c (dump_subexp_body_standard): Handle OP_BOOL.
+
 2021-01-12  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* f-exp.y (dot_ops): Rename to...

gdb/expprint.c

@@ -1121,11 +1121,18 @@ dump_subexp_body_standard (struct expression *exp,
       }
       break;
 
+    case OP_BOOL:
+      {
+	bool val = (bool) (exp->elts[elt].longconst);
+	fputs_filtered (val ? "TRUE" : "FALSE", stream);
+	elt += 2;
+      }
+      break;
+
     default:
     case OP_NULL:
     case MULTI_SUBSCRIPT:
     case OP_COMPLEX:
-    case OP_BOOL:
     case OP_M2_STRING:
     case OP_THIS:
     case OP_NAME:

gdb/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2021-01-12  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* gdb.fortran/debug-expr.exp: Add new tests.
+
 2021-01-12  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* gdb.fortran/dot-ops.exp: Add new tests.

gdb/testsuite/gdb.fortran/debug-expr.exp

@@ -41,3 +41,11 @@ gdb_continue_to_breakpoint "Break Here"
 
 gdb_test_no_output "set debug expression 1"
 gdb_test_debug_expr "print obj%three(1)%two(1)%one(1)%i" "\\\$$decimal = 1"
+gdb_test_debug_expr "print .TRUE."  [multi_line \
+					 "" \
+					 "\\s+0\\s+OP_BOOL\\s+TRUE" \
+					 "\\\$$decimal = \.TRUE\."]
+gdb_test_debug_expr "print .FALSE."  [multi_line \
+					  "" \
+					  "\\s+0\\s+OP_BOOL\\s+FALSE" \
+					  "\\\$$decimal = \.FALSE\."]