Fix location of sizeof/alignof (PR c++/80016)

PR c++/80016 reports an issue with bizarre underlined range
for a complicated expression.

The root cause for the incorrect *starting* location of that range
is that alignof and sizeof expressions currently have
start == finish == caret at the opening parenthesis of the
expression.

This patch fixes this by generating appropriate start and finish
locations for alignof and sizeof expressions.

gcc/cp/ChangeLog:
	PR c++/80016
	* parser.c (cp_parser_unary_expression):  Generate a location
	range for alignof and sizeof expressions.

gcc/testsuite/ChangeLog:
	PR c++/80016
	* g++.dg/plugin/diagnostic-test-expressions-1.C (test_sizeof): New
	test function.
	(test_alignof): New test function.

From-SVN: r247108

gcc/cp/ChangeLog

+2017-04-24  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c++/80016
+	* parser.c (cp_parser_unary_expression):  Generate a location
+	range for alignof and sizeof expressions.
+
 2017-04-24  Volker Reichelt  <v.reichelt@netcologne.de>
 
 	* parser.c (cp_parser_cv_qualifier_seq_opt): Add fix-it info to

gcc/cp/parser.c

@@ -7805,12 +7805,11 @@ cp_parser_unary_expression (cp_parser *parser, cp_id_kind * pidk,
 	  {
 	    tree operand, ret;
 	    enum tree_code op;
-	    location_t first_loc;
+	    location_t start_loc = token->location;
 
 	    op = keyword == RID_ALIGNOF ? ALIGNOF_EXPR : SIZEOF_EXPR;
 	    /* Consume the token.  */
 	    cp_lexer_consume_token (parser->lexer);
-	    first_loc = cp_lexer_peek_token (parser->lexer)->location;
 	    /* Parse the operand.  */
 	    operand = cp_parser_sizeof_operand (parser, keyword);
 
@@ -7846,9 +7845,21 @@ cp_parser_unary_expression (cp_parser *parser, cp_id_kind * pidk,
 		    TREE_SIDE_EFFECTS (ret) = 0;
 		    TREE_READONLY (ret) = 1;
 		  }
-		SET_EXPR_LOCATION (ret, first_loc);
 	      }
-	    return ret;
+
+	    /* Construct a location e.g. :
+	       alignof (expr)
+	       ^~~~~~~~~~~~~~
+	       with start == caret at the start of the "alignof"/"sizeof"
+	       token, with the endpoint at the final closing paren.  */
+	    location_t finish_loc
+	      = cp_lexer_previous_token (parser->lexer)->location;
+	    location_t compound_loc
+	      = make_location (start_loc, start_loc, finish_loc);
+
+	    cp_expr ret_expr (ret);
+	    ret_expr.set_location (compound_loc);
+	    return ret_expr;
 	  }
 
 	case RID_NEW:

gcc/testsuite/ChangeLog

+2017-04-24  David Malcolm  <dmalcolm@redhat.com>
+
+	PR c++/80016
+	* g++.dg/plugin/diagnostic-test-expressions-1.C (test_sizeof): New
+	test function.
+	(test_alignof): New test function.
+
 2017-04-24  Marc Glisse  <marc.glisse@inria.fr>
 
 	* gcc.dg/tree-ssa/cmpexactdiv-2.c: New file.

gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C

@@ -101,6 +101,72 @@ int test_postfix_incdec (int i)
 
 /* Unary operators.  ****************************************************/
 
+int test_sizeof (int i)
+{
+  __emit_expression_range (0, sizeof(int) + i); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, sizeof(int) + i);
+                               ~~~~~~~~~~~~^~~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, i + sizeof(int)); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, i + sizeof(int));
+                               ~~^~~~~~~~~~~~~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, sizeof i + i); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, sizeof i + i);
+                               ~~~~~~~~~^~~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, i + sizeof i); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, i + sizeof i);
+                               ~~^~~~~~~~~~
+   { dg-end-multiline-output "" } */
+}
+
+int test_alignof (int i)
+{
+  __emit_expression_range (0, alignof(int) + i); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, alignof(int) + i);
+                               ~~~~~~~~~~~~~^~~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, i + alignof(int)); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, i + alignof(int));
+                               ~~^~~~~~~~~~~~~~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, __alignof__(int) + i); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, __alignof__(int) + i);
+                               ~~~~~~~~~~~~~~~~~^~~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, i + __alignof__(int)); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, i + __alignof__(int));
+                               ~~^~~~~~~~~~~~~~~~~~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, __alignof__ i + i); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, __alignof__ i + i);
+                               ~~~~~~~~~~~~~~^~~
+   { dg-end-multiline-output "" } */
+
+  __emit_expression_range (0, i + __alignof__ i); /* { dg-warning "range" } */
+/* { dg-begin-multiline-output "" }
+   __emit_expression_range (0, i + __alignof__ i);
+                               ~~^~~~~~~~~~~~~~~
+   { dg-end-multiline-output "" } */
+}
+
 int test_prefix_incdec (int i)
 {
   __emit_expression_range (0, ++i ); /* { dg-warning "range" } */