On 10/29/2015 11:42 AM, Patrick Palka wrote:
On Thu, Oct 29, 2015 at 1:35 PM, Patrick Palka <patr...@parcs.ath.cx> wrote:
On Thu, Oct 29, 2015 at 12:49 PM, David Malcolm <dmalc...@redhat.com> wrote:
Attempting to bootstrap gcc with -Wmisleading-indentation enabled I ran
into a few failures where the indentation, although bad, was arguably
not misleading.
In regrename.c:scan_rtx_address:
1308 case PRE_MODIFY:
1309 /* If the target doesn't claim to handle autoinc, this must be
1310 something special, like a stack push. Kill this chain. */
1311 if (!AUTO_INC_DEC)
1312 action = mark_all_read;
1313
1314 break;
^ this is indented at the same level as the "action =" code,
but clearly isn't guarded by the if () at line 1311.
In gcc/fortran/io.c:gfc_match_open:
1997 {
1998 static const char *delim[] = { "APOSTROPHE", "QUOTE",
"NONE", NULL };
1999
2000 if (!is_char_type ("DELIM", open->delim))
2001 goto cleanup;
2002
2003 if (!compare_to_allowed_values ("DELIM", delim, NULL, NULL,
2004
open->delim->value.character.string,
2005 "OPEN", warn))
^ this is indented with the "goto cleanup;" due to
lines 2000-2001 not being indented enough, but
line 2003 clearly isn't guarded by the
"if (!is_char_type" conditional.
In gcc/function.c:locate_and_pad_parm:
4118 locate->slot_offset.constant = -initial_offset_ptr->constant;
4119 if (initial_offset_ptr->var)
4120 locate->slot_offset.var = size_binop (MINUS_EXPR, ssize_int
(0),
4121 initial_offset_ptr->var);
4122
4123 {
4124 tree s2 = sizetree;
4125 if (where_pad != none
4126 && (!tree_fits_uhwi_p (sizetree)
4127 || (tree_to_uhwi (sizetree) * BITS_PER_UNIT) %
round_boundary))
4128 s2 = round_up (s2, round_boundary / BITS_PER_UNIT);
4129 SUB_PARM_SIZE (locate->slot_offset, s2);
4130 }
^ this block is not guarded by the
"if (initial_offset_ptr->var)"
and the whitespace line (4122) is likely to make a
human reader of the code read it that way also.
In each case, a blank line separated the guarded code from followup code
that wasn't guarded, and to my eyes, the blank line makes the meaning of
the badly-indented code sufficiently clear that it seems unjustified to
issue a -Wmisleading-indentation warning.
This makes sense to me.
Though I've been thinking about proposing a simpler and more relaxed heuristic:
if (next_stmt_exploc.line - body_exploc.line > 1)
return false;
That is, don't warn if there are any lines between the (start of the)
body statement and the next statement.
This would catch the presence of blank lines as well as code like:
if (foo)
bar (an_argument_1,
an_argument_2);
baz ();
and
if (foo)
bar ();
/* Some comment. */
baz ();
Though I am not confident that we should not warn in such cases. At
this point whether some code is misleadingly indented or not becomes
pretty subjective (so it may be better to not warn?)
However we should definitely not warn on
if (foo)
bar ();
{
baz ();
}
Since that is valid GNU-style code :)
Wouldn't GNU style need the curleys lined up with the IF? and the call
to baz() indented two spaces relative to the curleys?
That's the way I've always done things when I've wanted to introduce a
binding scope like that.
jeff
