gas: require an operand to .startof.()/.sizeof.()

gas/ChangeLog

@@ -1,3 +1,9 @@
+2017-02-21  Jan Beulich  <jbeulich@suse.com>
+
+	* expr.c (operand): Handle missing operand to .startof.() and
+	.sizeof.().
+	* testsuite/gas/all/err-sizeof.s: New.
+
 2017-02-20  Alan Modra  <amodra@gmail.com>
 
 	PR 21118

gas/expr.c

@@ -1154,6 +1154,10 @@ operand (expressionS *expressionP, enum expr_mode mode)
 		   || input_line_pointer[1] == 'T');
 	  input_line_pointer += start ? 8 : 7;
 	  SKIP_WHITESPACE ();
+
+	  /* Cover for the as_bad () invocations below.  */
+	  expressionP->X_op = O_absent;
+
 	  if (*input_line_pointer != '(')
 	    as_bad (_("syntax error in .startof. or .sizeof."));
 	  else
@@ -1163,6 +1167,16 @@ operand (expressionS *expressionP, enum expr_mode mode)
 	      ++input_line_pointer;
 	      SKIP_WHITESPACE ();
 	      c = get_symbol_name (& name);
+	      if (! *name)
+		{
+		  as_bad (_("expected symbol name"));
+		  (void) restore_line_pointer (c);
+		  if (c != ')')
+		    ignore_rest_of_line ();
+		  else
+		    ++input_line_pointer;
+		  break;
+		}
 
 	      buf = concat (start ? ".startof." : ".sizeof.", name,
 			    (char *) NULL);
@@ -1306,6 +1320,14 @@ operand (expressionS *expressionP, enum expr_mode mode)
 	      SKIP_WHITESPACE_AFTER_NAME ();
 
 	      c = get_symbol_name (& name);
+	      if (! *name)
+		{
+		  as_bad (_("expected symbol name"));
+		  expressionP->X_op = O_absent;
+		  (void) restore_line_pointer (c);
+		  ignore_rest_of_line ();
+		  break;
+		}
 
 	      buf = concat (start ? ".startof." : ".sizeof.", name,
 			    (char *) NULL);

gas/testsuite/gas/all/err-sizeof.s

@@ -0,0 +1,21 @@
+;# .sizeof. and .startof. operator diagnostics
+;# { dg-do assemble }
+	.long	.sizeof.(a b)		;# { dg-error "Error: syntax error" }
+	.long	.startof.(x y)		;# { dg-error "Error: syntax error" }
+	.long	.sizeof.(a+b)		;# { dg-error "Error: syntax error" }
+	.long	.startof.(x-y)		;# { dg-error "Error: syntax error" }
+	.long	.sizeof.("a+b")
+	.long	.startof.("x-y")
+	.long	.sizeof.()		;# { dg-error "Error: expected symbol name" }
+	.long	.startof.()		;# { dg-error "Error: expected symbol name" }
+;# We don't really care about these, but I didn't find a way to discard
+;# them, and I also don't want to use dg-excess-errors here.
+;# { dg-error "junk at end" "" { target *-*-* } 3 }
+;# { dg-error "junk at end" "junk" { target *-*-* } 4 }
+;# { dg-error "junk at end" "junk" { target *-*-* } 5 }
+;# { dg-error "UND" "undefined" { target *-*-* } 5 }
+;# { dg-error "junk at end" "junk" { target *-*-* } 6 }
+;# { dg-error "UND" "undefined" { target *-*-* } 6 }
+;# { dg-error "too complex" "too complex" { target powerpc*-*-* } 6 }
+;# { dg-warning "zero assumed" "missing" { target *-*-* } 9 }
+;# { dg-warning "zero assumed" "missing" { target *-*-* } 10 }