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Re: [PATCH] v2: Fix location of typeid() (PR c++/80014)


OK.

On Wed, Jun 28, 2017 at 7:13 PM, David Malcolm <dmalcolm@redhat.com> wrote:
> On Wed, 2017-03-15 at 16:35 -0400, Jason Merrill wrote:
>> On Tue, Mar 14, 2017 at 9:05 PM, David Malcolm <dmalcolm@redhat.com>
>> wrote:
>> > OK for trunk now, or should this wait until stage 1?
>>
>> Stage 1.
>>
>> > +       cp_token *close_paren = cp_parser_require (parser,
>> > CPP_CLOSE_PAREN,
>> > +                                                  RT_CLOSE_PAREN);
>> > +       location_t end_loc = close_paren ?
>> > +         close_paren->location : UNKNOWN_LOCATION;
>> >         /* If all went well, simply lookup the type-id.  */
>> >         if (cp_parser_parse_definitely (parser))
>> >           postfix_expression = get_typeid (type,
>> > tf_warning_or_error);
>> > @@ -6527,13 +6530,23 @@ cp_parser_postfix_expression (cp_parser
>> > *parser, bool address_p, bool cast_p,
>> >             /* Compute its typeid.  */
>> >             postfix_expression = build_typeid (expression,
>> > tf_warning_or_error);
>> >             /* Look for the `)' token.  */
>> > -           cp_parser_require (parser, CPP_CLOSE_PAREN,
>> > RT_CLOSE_PAREN);
>> > +           close_paren
>> > +             = cp_parser_require (parser, CPP_CLOSE_PAREN,
>> > RT_CLOSE_PAREN);
>> > +           end_loc = close_paren ? close_paren->location :
>> > UNKNOWN_LOCATION;
>>
>> In both cases you're setting end_loc from close_paren, so how about
>> only computing it once, closer to where it's used?
>>
>> Jason
>
> Here's an updated version of the patch; it only looks up the location
> of the close paren once (and adds another test case).  I also replaced
> the ?: with an if () to avoid setting finish to UNKNOWN_LOCATION.
>
> Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu.
>
> OK for trunk?
>
> Blurb from v1:
>
> PR c++/80014 reports an issue where no caret is printed when issuing an
> error for this bogus code:
>   !typeid(void);
>
> Root cause is that we're not setting up the location for the cp_expr for
> the typeid expression, so that
>   !typeid(void)
> has start == caret at the '!', but finish == UNKNOWN_LOCATION, and so
> the layout ctor within diagnostic-show-locus.c filters out the primary
> range, and hence layout::should_print_annotation_line_p returns false.
>
> This patch fixes things by setting up a location for the typeid
> expression when parsing it.
>
> gcc/cp/ChangeLog:
>         PR c++/80014
>         * parser.c (cp_parser_postfix_expression): Construct a location
>         for typeid expressions.
>
> gcc/testsuite/ChangeLog:
>         PR c++/80014
>         * g++.dg/plugin/diagnostic-test-expressions-1.C (std::type_info):
>         Add declaration.
>         (test_typeid): New test function.
> ---
>  gcc/cp/parser.c                                    | 18 ++++++++++--
>  .../g++.dg/plugin/diagnostic-test-expressions-1.C  | 32 ++++++++++++++++++++++
>  2 files changed, 48 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> index 4adf9aa..49003e4 100644
> --- a/gcc/cp/parser.c
> +++ b/gcc/cp/parser.c
> @@ -6517,7 +6517,8 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
>         /* Look for the `)' token.  Otherwise, we can't be sure that
>            we're not looking at an expression: consider `typeid (int
>            (3))', for example.  */
> -       cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
> +       cp_token *close_paren = cp_parser_require (parser, CPP_CLOSE_PAREN,
> +                                                  RT_CLOSE_PAREN);
>         /* If all went well, simply lookup the type-id.  */
>         if (cp_parser_parse_definitely (parser))
>           postfix_expression = get_typeid (type, tf_warning_or_error);
> @@ -6531,13 +6532,26 @@ cp_parser_postfix_expression (cp_parser *parser, bool address_p, bool cast_p,
>             /* Compute its typeid.  */
>             postfix_expression = build_typeid (expression, tf_warning_or_error);
>             /* Look for the `)' token.  */
> -           cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
> +           close_paren
> +             = cp_parser_require (parser, CPP_CLOSE_PAREN, RT_CLOSE_PAREN);
>           }
>         /* Restore the saved message.  */
>         parser->type_definition_forbidden_message = saved_message;
>         /* `typeid' may not appear in an integral constant expression.  */
>         if (cp_parser_non_integral_constant_expression (parser, NIC_TYPEID))
>           postfix_expression = error_mark_node;
> +
> +       /* Construct a location e.g. :
> +            typeid (expr)
> +            ^~~~~~~~~~~~~
> +          ranging from the start of the "typeid" token to the final closing
> +          paren, with the caret at the start.  */
> +       if (close_paren)
> +         {
> +           location_t typeid_loc
> +             = make_location (start_loc, start_loc, close_paren->location);
> +           postfix_expression.set_location (typeid_loc);
> +         }
>        }
>        break;
>
> diff --git a/gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C b/gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C
> index 2c004f3..62d3c36 100644
> --- a/gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C
> +++ b/gcc/testsuite/g++.dg/plugin/diagnostic-test-expressions-1.C
> @@ -848,3 +848,35 @@ tests::test_method_calls ()
>                                 ~~~~~~~~~~~~~~~~~~^~
>     { dg-end-multiline-output "" } */
>  }
> +
> +namespace std
> +{
> +  class type_info { public: int foo; };
> +}
> +
> +void test_typeid (int i)
> +{
> +  __emit_expression_range (0, &typeid(i)); /* { dg-warning "range" } */
> +/* { dg-begin-multiline-output "" }
> +   __emit_expression_range (0, &typeid(i));
> +                               ^~~~~~~~~~
> +   { dg-end-multiline-output "" } */
> +
> +  __emit_expression_range (0, &typeid(int)); /* { dg-warning "range" } */
> +/* { dg-begin-multiline-output "" }
> +   __emit_expression_range (0, &typeid(int));
> +                               ^~~~~~~~~~~~
> +   { dg-end-multiline-output "" } */
> +
> +  __emit_expression_range (0, &typeid(i * 2)); /* { dg-warning "range" } */
> +/* { dg-begin-multiline-output "" }
> +   __emit_expression_range (0, &typeid(i * 2));
> +                               ^~~~~~~~~~~~~~
> +   { dg-end-multiline-output "" } */
> +
> +  __emit_expression_range (0, typeid(int).foo); /* { dg-warning "range" } */
> +/* { dg-begin-multiline-output "" }
> +   __emit_expression_range (0, typeid(int).foo);
> +                               ~~~~~~~~~~~~^~~
> +   { dg-end-multiline-output "" } */
> +}
> --
> 1.8.5.3
>


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