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c-lex.c (c_lex_with_flags): For CPP_COMMENT token with PREV_FALLTHROUGH...

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* c-lex.c (c_lex_with_flags) <case CPP_COMMENT>: For CPP_COMMENT
	token with PREV_FALLTHROUGH, skip all following CPP_PADDING and
	CPP_COMMENT tokens and set add_flags to PREV_FALLTHROUGH afterwards.

	* doc/invoke.texi (-Wimplicit-fallthrough): Document the accepted
	FALLTHRU comment styles.

	* lex.c (fallthrough_comment_p): Fix off-by-one size comparison
	errors, cleanup.
	(_cpp_lex_direct): Allow arbitrary comments in between
	fallthrough_comment_p comment and following token.

	* c-c++-common/Wimplicit-fallthrough-23.c: New test.
	* c-c++-common/Wimplicit-fallthrough-24.c: New test.

From-SVN: r240884
This commit is contained in:
Jakub Jelinek 2016-10-08 12:48:54 +02:00 • committed by Jakub Jelinek
parent 6dc29c6db1
commit 7bad794aa0
9 changed files with 203 additions and 25 deletions
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5
gcc/ChangeLog
View file

@ -1,3 +1,8 @@
2016-10-08 Jakub Jelinek <jakub@redhat.com>
* doc/invoke.texi (-Wimplicit-fallthrough): Document the accepted
FALLTHRU comment styles.
2016-10-07 Andrew Pinski <apinski@cavium.com>
* config/aarch64/aarch64-arches.def (AARCH64_ARCH): #undef at the end.

6
gcc/c-family/ChangeLog
View file

@ -1,3 +1,9 @@
2016-10-08 Jakub Jelinek <jakub@redhat.com>
* c-lex.c (c_lex_with_flags) <case CPP_COMMENT>: For CPP_COMMENT
token with PREV_FALLTHROUGH, skip all following CPP_PADDING and
CPP_COMMENT tokens and set add_flags to PREV_FALLTHROUGH afterwards.
2016-10-07 Jakub Jelinek <jakub@redhat.com>
Implement LWG2296 helper intrinsic

18
gcc/c-family/c-lex.c
View file

@ -596,9 +596,21 @@ c_lex_with_flags (tree *value, location_t *loc, unsigned char *cpp_flags,
case CPP_MACRO_ARG:
gcc_unreachable ();
/* CPP_COMMENT will appear when compiling with -C and should be
ignored. */
case CPP_COMMENT:
/* CPP_COMMENT will appear when compiling with -C. Ignore, except
when it is a FALLTHROUGH comment, in that case set
PREV_FALLTHROUGH flag on the next non-comment token. */
case CPP_COMMENT:
if (tok->flags & PREV_FALLTHROUGH)
{
do
{
tok = cpp_get_token_with_location (parse_in, loc);
type = tok->type;
}
while (type == CPP_PADDING || type == CPP_COMMENT);
add_flags |= PREV_FALLTHROUGH;
goto retry_after_at;
}
goto retry;
default:

24
gcc/doc/invoke.texi
View file

@ -4170,10 +4170,26 @@ C++17 provides a standard way to suppress the @option{-Wimplicit-fallthrough}
warning using @code{[[fallthrough]];} instead of the GNU attribute. In C++11
or C++14 users can use @code{[[gnu::fallthrough]];}, which is a GNU extension.
Instead of the these attributes, it is also possible to add a "falls through"
comment to silence the warning. GCC accepts a wide range of such comments,
for example all of "Falls through.", "fallthru", "FALLS-THROUGH" work. This
comment needs to consist of two words merely, optionally followed by periods
or whitespaces.
comment to silence the warning. The whole body of the C or C++ style comment
should match one of the following regular expressions:
@itemize @bullet
@item @code{-fallthrough}
@item @code{@@fallthrough@@}
@item @code{[ \t]*FALL(S | |-)?THR(OUGH|U)\.?[ \t]*}
@item @code{[ \t]*Fall((s | |-)[Tt]|t)hr(ough|u)\.?[ \t]*}
@item @code{[ \t]*fall(s | |-)?thr(ough|u)\.?[ \t]*}
@end itemize
and the comment needs to be followed after optional whitespace and other comments
by @code{case} or @code{default} keywords or by a user label that preceeds some
@code{case} or @code{default} label.
@smallexample
@group

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2016-10-08 Jakub Jelinek <jakub@redhat.com>
* c-c++-common/Wimplicit-fallthrough-23.c: New test.
* c-c++-common/Wimplicit-fallthrough-24.c: New test.
2016-10-07 Fritz Reese <fritzoreese@gmail.com>
* gfortran.dg/dec_union_11.f90: New testcase.

123
gcc/testsuite/c-c++-common/Wimplicit-fallthrough-23.c Normal file
View file

@ -0,0 +1,123 @@
/* { dg-do compile } */
/* { dg-options "-Wimplicit-fallthrough" } */
void bar (int);
void
foo (int i)
{
switch (i)
{
case 1:
bar (1); /* { dg-bogus "this statement may \[laf]* through" } */
/* FALLTHROUGH */
case 2:
bar (2);
break;
case 3:
bar (3); /* { dg-bogus "this statement may \[laf]* through" } */
/* FALLS THRU. */
/* Some other comment. */
case 4:
bar (4);
break;
case 7:
bar (7); /* { dg-bogus "this statement may \[laf]* through" } */
/* Some comment. */
/* fallthrough. */
/* Some other comment. */
/* And yet another. */
case 8:
bar (8);
break;
case 15:
bar (15); /* { dg-bogus "this statement may \[laf]* through" } */
/*-fallthrough*/
case 16:
bar (16);
break;
case 17:
bar (17); /* { dg-bogus "this statement may \[laf]* through" } */
/*@fallthrough@*/
case 18:
bar (18);
break;
case 23:
bar (23); /* { dg-bogus "this statement may \[laf]* through" } */
/*fallthru*/
case 24:
bar (24);
break;
case 31:
bar (31); /* { dg-bogus "this statement may \[laf]* through" } */
/*Falls thru*/
case 32:
bar (32);
break;
case 33:
bar (33); /* { dg-bogus "this statement may \[laf]* through" } */
/*Fall-through*/
case 34:
bar (34);
break;
default:
break;
}
switch (i)
{
case 1:
bar (1); /* { dg-bogus "this statement may \[laf]* through" } */
// FALLTHROUGH
case 2:
bar (2);
break;
case 3:
bar (3); /* { dg-bogus "this statement may \[laf]* through" } */
// FALLS THRU.
// Some other comment.
case 4:
bar (4);
break;
case 7:
bar (7); /* { dg-bogus "this statement may \[laf]* through" } */
// Some comment.
// fallthrough
// Some other comment.
// And yet another.
case 8:
bar (8);
break;
case 15:
bar (15); /* { dg-bogus "this statement may \[laf]* through" } */
//-fallthrough
case 16:
bar (16);
break;
case 17:
bar (17); /* { dg-bogus "this statement may \[laf]* through" } */
//@fallthrough@
case 18:
bar (18);
break;
case 23:
bar (23); /* { dg-bogus "this statement may \[laf]* through" } */
//fallthru
case 24:
bar (24);
break;
case 31:
bar (31); /* { dg-bogus "this statement may \[laf]* through" } */
//Falls thru
case 32:
bar (32);
break;
case 33:
bar (33); /* { dg-bogus "this statement may \[laf]* through" } */
//Fall-through
case 34:
bar (34);
break;
default:
break;
}
}

4
gcc/testsuite/c-c++-common/Wimplicit-fallthrough-24.c Normal file
View file

@ -0,0 +1,4 @@
/* { dg-do compile } */
/* { dg-options "-Wimplicit-fallthrough -C" } */
#include "Wimplicit-fallthrough-23.c"

7
libcpp/ChangeLog
View file

@ -1,3 +1,10 @@
2016-10-08 Jakub Jelinek <jakub@redhat.com>
* lex.c (fallthrough_comment_p): Fix off-by-one size comparison
errors, cleanup.
(_cpp_lex_direct): Allow arbitrary comments in between
fallthrough_comment_p comment and following token.
2016-10-04 Kelvin Nilsen <kelvin@gcc.gnu.org>
PR target/77847

36
libcpp/lex.c
View file

@ -2061,7 +2061,7 @@ fallthrough_comment_p (cpp_reader *pfile, const unsigned char *comment_start)
}
/* Whole comment contents (regex):
[ \t]*FALL(S | |-)?THR(OUGH|U)\.?[ \t]*
[ \t]*Fall(s | |-)?[Tt]hr(ough|u)\.?[ \t]*
[ \t]*Fall((s | |-)[Tt]|t)hr(ough|u)\.?[ \t]*
[ \t]*fall(s | |-)?thr(ough|u)\.?[ \t]*
*/
else
@ -2071,30 +2071,27 @@ fallthrough_comment_p (cpp_reader *pfile, const unsigned char *comment_start)
unsigned char f = *from;
if (f != 'F' && f != 'f')
return false;
if ((size_t) (pfile->buffer->cur - from) < sizeof "fallthrough")
if ((size_t) (pfile->buffer->cur - from) < sizeof "fallthru" - 1)
return false;
bool all_upper = false;
if (f == 'F' && memcmp (from + 1, "ALL", sizeof "ALL" - 1) == 0)
all_upper = true;
else if (memcmp (from + 1, "all", sizeof "all" - 1))
return false;
if (from[sizeof "fall" - 1] == (all_upper ? 'S' : 's')
&& from[sizeof "falls" - 1] == ' ')
from += sizeof "falls " - 1;
else if (from[sizeof "fall" - 1] == ' '
|| from[sizeof "fall" - 1] == '-')
from += sizeof "fall " - 1;
else if (from[sizeof "fall" - 1] != (all_upper ? 'T' : 't'))
from += sizeof "fall" - 1;
if (*from == (all_upper ? 'S' : 's') && from[1] == ' ')
from += 2;
else if (*from == ' ' || *from == '-')
from++;
else if (*from != (all_upper ? 'T' : 't'))
return false;
else
from += sizeof "fall" - 1;
if ((f == 'f' || *from != 'T') && (all_upper || *from != 't'))
return false;
if ((size_t) (pfile->buffer->cur - from) < sizeof "thru")
if ((size_t) (pfile->buffer->cur - from) < sizeof "thru" - 1)
return false;
if (memcmp (from + 1, all_upper ? "HRU" : "hru", sizeof "hru" - 1))
{
if ((size_t) (pfile->buffer->cur - from) < sizeof "through")
if ((size_t) (pfile->buffer->cur - from) < sizeof "through" - 1)
return false;
if (memcmp (from + 1, all_upper ? "HROUGH" : "hrough",
sizeof "hrough" - 1))
@ -2399,7 +2396,8 @@ _cpp_lex_direct (cpp_reader *pfile)
{
cppchar_t c;
cpp_buffer *buffer;
const unsigned char *comment_start = NULL;
const unsigned char *comment_start;
bool fallthrough_comment = false;
cpp_token *result = pfile->cur_token++;
fresh_line:
@ -2427,7 +2425,7 @@ _cpp_lex_direct (cpp_reader *pfile)
return result;
}
if (buffer != pfile->buffer)
comment_start = NULL;
fallthrough_comment = false;
if (!pfile->keep_tokens)
{
pfile->cur_run = &pfile->base_run;
@ -2536,8 +2534,7 @@ _cpp_lex_direct (cpp_reader *pfile)
}
/* Signal FALLTHROUGH comment followed by another token. */
if (comment_start
&& fallthrough_comment_p (pfile, comment_start))
if (fallthrough_comment)
result->flags |= PREV_FALLTHROUGH;
break;
@ -2624,13 +2621,16 @@ _cpp_lex_direct (cpp_reader *pfile)
break;
}
if (fallthrough_comment_p (pfile, comment_start))
fallthrough_comment = true;
if (!pfile->state.save_comments)
{
result->flags |= PREV_WHITE;
goto update_tokens_line;
}
if (fallthrough_comment_p (pfile, comment_start))
if (fallthrough_comment)
result->flags |= PREV_FALLTHROUGH;
/* Save the comment as a token in its own right. */