Re: [PATCH 1/6] diagnostics: Fix macro tracking for ad-hoc locations

[David Malcolm <dmalcolm@redhat.com>]

On Fri, 2022-11-04 at 09:44 -0400, Lewis Hyatt via Gcc-patches wrote:
> The result of linemap_resolve_location() can be an ad-hoc location,
> if that is
> what was stored in a relevant macro map. 
> maybe_unwind_expanded_macro_loc()
> did not previously handle this case, causing it to print the wrong
> tracking
> information for an example such as the new testcase macro-trace-1.c. 
> Fix that
> by checking for ad-hoc locations where needed.

Thanks; looks good to me.
Dave

> 
> gcc/ChangeLog:
> 
>         * tree-diagnostic.cc (maybe_unwind_expanded_macro_loc):
> Handle ad-hoc
>         location in return value of linemap_resolve_location().
> 
> gcc/testsuite/ChangeLog:
> 
>         * c-c++-common/cpp/macro-trace-1.c: New test.
> ---
>  gcc/testsuite/c-c++-common/cpp/macro-trace-1.c | 4 ++++
>  gcc/tree-diagnostic.cc                         | 7 +++++--
>  2 files changed, 9 insertions(+), 2 deletions(-)
>  create mode 100644 gcc/testsuite/c-c++-common/cpp/macro-trace-1.c
> 
> diff --git a/gcc/testsuite/c-c++-common/cpp/macro-trace-1.c
> b/gcc/testsuite/c-c++-common/cpp/macro-trace-1.c
> new file mode 100644
> index 00000000000..34cfbb3dad3
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/cpp/macro-trace-1.c
> @@ -0,0 +1,4 @@
> +/* This token is long enough to require an ad-hoc location. Make
> sure that
> +   the macro trace still prints properly.  */
> +#define X "0123456789012345678901234567689" /* { dg-error {expected
> .* before string constant} } */
> +X /* { dg-note {in expansion of macro 'X'} } */
> diff --git a/gcc/tree-diagnostic.cc b/gcc/tree-diagnostic.cc
> index 0d79fe3c3c1..5cf3a1c17d2 100644
> --- a/gcc/tree-diagnostic.cc
> +++ b/gcc/tree-diagnostic.cc
> @@ -190,14 +190,17 @@ maybe_unwind_expanded_macro_loc
> (diagnostic_context *context,
>          location_t l = 
>            linemap_resolve_location (line_table, resolved_def_loc,
>                                      LRK_SPELLING_LOCATION,  &m);
> -        if (l < RESERVED_LOCATION_COUNT || LINEMAP_SYSP (m))
> +       location_t l0 = l;
> +       if (IS_ADHOC_LOC (l0))
> +         l0 = get_location_from_adhoc_loc (line_table, l0);
> +       if (l0 < RESERVED_LOCATION_COUNT || LINEMAP_SYSP (m))
>            continue;
>          
>         /* We need to print the context of the macro definition only
>            when the locus of the first displayed diagnostic
> (displayed
>            before this trace) was inside the definition of the
>            macro.  */
> -        int resolved_def_loc_line = SOURCE_LINE (m, l);
> +       const int resolved_def_loc_line = SOURCE_LINE (m, l0);
>          if (ix == 0 && saved_location_line != resolved_def_loc_line)
>            {
>              diagnostic_append_note (context, resolved_def_loc, 
>