Re: [PATCH 2/2] PR c/68187: fix overzealous -Wmisleading-indentation (comment #1)

[Jeff Law <law@redhat.com>]

On 03/03/2016 08:21 AM, David Malcolm wrote:
> Comment #1 of PR c/68187 identified another overzealous warning
> from -Wmisleading-indentation, with OpenSSL 1.0.1, on this poorly
> indented code:
>
> 115    if (locked)
> 116        i = CRYPTO_add(&e->struct_ref, -1, CRYPTO_LOCK_ENGINE);
> 117    else
> 118        i = --e->struct_ref;
> 119    engine_ref_debug(e, 0, -1)
> 120        if (i > 0)
> 121        return 1;
Egad.  How do people read this code when they have to understand it and 
make changes.    What a steaming pile of .....


>
> Root cause is that "engine_ref_debug" is actually a debugging macro
> that was empty in the given configuration, so the code effectively
> was:
>
> 117    else                      // GUARD
> 118        i = --e->struct_ref;  // BODY
> 119
> 120        if (i > 0)            // NEXT
>
> hence the warning.
No surprise we triggered seeing that.

>
> OK for trunk?
>
> Note: one of the new test cases adds a dg-warning/dg-message pair, and so
> would require updating if/when the wording change posted here:
>    https://gcc.gnu.org/ml/gcc-patches/2016-03/msg00068.html
>    ("[PATCH] PR c/69993: improvements to wording of -Wmisleading-indentation")
> is applied.
>
> gcc/c-family/ChangeLog:
> 	PR c/68187
> 	* c-indentation.c (get_visual_column): Move code to determine next
> 	tab stop to...
> 	(next_tab_stop): ...this new function.
> 	(line_contains_hash_if): Delete function.
> 	(detect_preprocessor_logic): Delete function.
> 	(get_first_nws_vis_column): New function.
> 	(detect_intervening_unindent): New function.
> 	(should_warn_for_misleading_indentation): Replace call to
> 	detect_preprocessor_logic with a call to
> 	detect_intervening_unindent.
>
> gcc/testsuite/ChangeLog:
> 	PR c/68187
> 	* c-c++-common/Wmisleading-indentation.c (fn_42_a): New test
> 	function.
> 	(fn_42_b): Likewise.
> 	(fn_42_c): Likewise.
OK.


Jeff