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Handle :: tokens in C for C2x. 

As part of adding [[]]-style attributes, C2x adds the token :: for use
in scoped attribute names.

This patch adds corresponding support for that token in C to GCC.  The
token is supported both for C2x and for older gnu* standards (on the
basis that extensions are normally supported in older gnu* versions;
people will expect to be able to use [[]] attributes, before C2x is
the default, without needing to use -std=gnu2x).

There are no cases in older C standards where the token : can be
followed by a token starting with : in syntactically valid sources;
the only cases the :: token could break in older standard C thus are
ones involving concatenation of pp-tokens where the result does not
end up as tokens (e.g., gets stringized).  In GNU C extensions, the
main case where :: might appear in existing sources is in asm
statements, and the C parser is thus made to handle it like two
consecutive : tokens, which the C++ parser already does.  A limited
test of various positionings of :: in asm statements is added to the
testsuite (in particular, to cover the syntax error when :: means too
many colons but a single : would be OK), but existing tests cover a
variety of styles there anyway.

Technically there are cases in Objective-C and OpenMP for which this
also changes how previously valid code is lexed: the objc-selector-arg
syntax allows multiple consecutive : tokens (although I don't think
they are particularly useful there), while OpenMP syntax includes
array section syntax such as [:] which, before :: was a token, could
also be written as [::> (there might be other OpenMP cases potentially
affected, I didn't check all the OpenMP syntax in detail).  I don't
think either of those cases affects the basis for supporting the ::
token in all -std=gnu* modes, or that there is any obvious need to
special-case handling of CPP_SCOPE tokens for those constructs the way
there is for asm statements.

cpp_avoid_paste, which determines when spaces need adding between
tokens in preprocessed output where there wouldn't otherwise be
whitespace between them (e.g. if stringized), already inserts space
between : and : unconditionally, rather than only for C++, so no
change is needed there (but a C2x test is added that such space is
indeed inserted).

Bootstrapped with no regressions on x86-64-pc-linux-gnu.

gcc/c:
	* c-parser.c (c_parser_asm_statement): Handle CPP_SCOPE like two
	CPP_COLON tokens.

gcc/testsuite:
	* gcc.dg/asm-scope-1.c, gcc.dg/cpp/c11-scope-1.c,
	gcc.dg/cpp/c17-scope-1.c, gcc.dg/cpp/c2x-scope-1.c,
	gcc.dg/cpp/c2x-scope-2.c, gcc.dg/cpp/c90-scope-1.c,
	gcc.dg/cpp/c94-scope-1.c, gcc.dg/cpp/c99-scope-1.c,
	gcc.dg/cpp/gnu11-scope-1.c, gcc.dg/cpp/gnu17-scope-1.c,
	gcc.dg/cpp/gnu89-scope-1.c, gcc.dg/cpp/gnu99-scope-1.c: New tests.

libcpp:
	* include/cpplib.h (struct cpp_options): Add member scope.
	* init.c (struct lang_flags, lang_defaults): Likewise.
	(cpp_set_lang): Set scope member of pfile.
	* lex.c (_cpp_lex_direct): Test CPP_OPTION (pfile, scope) not
	CPP_OPTION (pfile, cplusplus) for creating CPP_SCOPE tokens.

From-SVN: r276434
This commit is contained in:
Joseph Myers 2019-10-02 01:08:40 +01:00 committed by Joseph Myers
parent e9c9a142b4
commit 93313b94fe
19 changed files with 187 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
gcc/c/ChangeLog
View File

@ -1,3 +1,8 @@
2019-10-02 Joseph Myers <joseph@codesourcery.com>
* c-parser.c (c_parser_asm_statement): Handle CPP_SCOPE like two
CPP_COLON tokens.
2019-10-01 Richard Sandiford <richard.sandiford@arm.com>
* c-objc-common.c (useful_aka_type_p): New function.

25
gcc/c/c-parser.c
View File

@ -6411,7 +6411,9 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll,
The form with asm-goto-operands is valid if and only if the
asm-qualifier-list contains goto, and is the only allowed form in that case.
Duplicate asm-qualifiers are not allowed. */
Duplicate asm-qualifiers are not allowed.
The :: token is considered equivalent to two consecutive : tokens. */
static tree
c_parser_asm_statement (c_parser *parser)
@ -6509,17 +6511,28 @@ c_parser_asm_statement (c_parser *parser)
nsections = 3 + is_goto;
for (section = 0; section < nsections; ++section)
{
if (!c_parser_require (parser, CPP_COLON,
is_goto
? G_("expected %<:%>")
: G_("expected %<:%> or %<)%>"),
UNKNOWN_LOCATION, is_goto))
if (c_parser_next_token_is (parser, CPP_SCOPE))
{
++section;
if (section == nsections)
{
c_parser_error (parser, "expected %<)%>");
goto error_close_paren;
}
c_parser_consume_token (parser);
}
else if (!c_parser_require (parser, CPP_COLON,
is_goto
? G_("expected %<:%>")
: G_("expected %<:%> or %<)%>"),
UNKNOWN_LOCATION, is_goto))
goto error_close_paren;
/* Once past any colon, we're no longer a simple asm. */
simple = false;
if ((!c_parser_next_token_is (parser, CPP_COLON)
&& !c_parser_next_token_is (parser, CPP_SCOPE)
&& !c_parser_next_token_is (parser, CPP_CLOSE_PAREN))
|| section == 3)
switch (section)

9
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,12 @@
2019-10-02 Joseph Myers <joseph@codesourcery.com>
* gcc.dg/asm-scope-1.c, gcc.dg/cpp/c11-scope-1.c,
gcc.dg/cpp/c17-scope-1.c, gcc.dg/cpp/c2x-scope-1.c,
gcc.dg/cpp/c2x-scope-2.c, gcc.dg/cpp/c90-scope-1.c,
gcc.dg/cpp/c94-scope-1.c, gcc.dg/cpp/c99-scope-1.c,
gcc.dg/cpp/gnu11-scope-1.c, gcc.dg/cpp/gnu17-scope-1.c,
gcc.dg/cpp/gnu89-scope-1.c, gcc.dg/cpp/gnu99-scope-1.c: New tests.
2019-10-01 David Malcolm <dmalcolm@redhat.com>
* gcc.dg/plugin/diagnostic_group_plugin.c (test_begin_group_cb):

27
gcc/testsuite/gcc.dg/asm-scope-1.c Normal file
View File

@ -0,0 +1,27 @@
/* Test :: token handling in asm. */
/* { dg-do compile } */
/* { dg-options "-std=gnu2x" } */
void
f (void)
{
asm ("");
asm ("" : );
asm ("" : :);
asm ("" ::);
asm ("" : : :);
asm ("" :: :);
asm ("" : ::);
asm goto ("" : : : : lab);
asm goto ("" :: : : lab);
asm goto ("" : :: : lab);
asm goto ("" : : :: lab);
asm goto ("" :: :: lab);
lab: ;
/* Test errors when :: is at the end of asm and only one : allowed. */
asm ("" : : ::); /* { dg-error "expected" } */
asm ("" :: ::); /* { dg-error "expected" } */
asm goto ("" : : : :: lab); /* { dg-error "expected" } */
asm goto ("" :: : :: lab); /* { dg-error "expected" } */
asm goto ("" : :: :: lab); /* { dg-error "expected" } */
}

8
gcc/testsuite/gcc.dg/cpp/c11-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token not in C11. */
/* { dg-do preprocess } */
/* { dg-options "-std=c11 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :) /* { dg-error "does not give a valid preprocessing token" } */
CONCAT (::, >)

8
gcc/testsuite/gcc.dg/cpp/c17-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token not in C17. */
/* { dg-do preprocess } */
/* { dg-options "-std=c17 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :) /* { dg-error "does not give a valid preprocessing token" } */
CONCAT (::, >)

8
gcc/testsuite/gcc.dg/cpp/c2x-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token in C2x. */
/* { dg-do preprocess } */
/* { dg-options "-std=c2x -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :)
CONCAT (::, >) /* { dg-error "does not give a valid preprocessing token" } */

11
gcc/testsuite/gcc.dg/cpp/c2x-scope-2.c Normal file
View File

@ -0,0 +1,11 @@
/* Test :: token in C2x: preprocessed output. */
/* { dg-do preprocess } */
/* { dg-options "-std=c2x -pedantic-errors -P" } */
#define COLON() :
#define TEST() ABC
/* This must have a space inserted between the two ':' tokens in
preprocessed output. */
TEST()COLON()COLON()TEST()
/* { dg-final { scan-file c2x-scope-2.i "ABC: :ABC" } } */

7
gcc/testsuite/gcc.dg/cpp/c90-scope-1.c Normal file
View File

@ -0,0 +1,7 @@
/* Test :: token not in C90. */
/* { dg-do preprocess } */
/* { dg-options "-std=c90 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :) /* { dg-error "does not give a valid preprocessing token" } */

8
gcc/testsuite/gcc.dg/cpp/c94-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token not in C94. */
/* { dg-do preprocess } */
/* { dg-options "-std=iso9899:199409 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :) /* { dg-error "does not give a valid preprocessing token" } */
CONCAT (::, >)

8
gcc/testsuite/gcc.dg/cpp/c99-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token not in C99. */
/* { dg-do preprocess } */
/* { dg-options "-std=c99 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :) /* { dg-error "does not give a valid preprocessing token" } */
CONCAT (::, >)

8
gcc/testsuite/gcc.dg/cpp/gnu11-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token in gnu11. */
/* { dg-do preprocess } */
/* { dg-options "-std=gnu11 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :)
CONCAT (::, >) /* { dg-error "does not give a valid preprocessing token" } */

8
gcc/testsuite/gcc.dg/cpp/gnu17-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token in gnu17. */
/* { dg-do preprocess } */
/* { dg-options "-std=gnu17 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :)
CONCAT (::, >) /* { dg-error "does not give a valid preprocessing token" } */

8
gcc/testsuite/gcc.dg/cpp/gnu89-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token in gnu89. */
/* { dg-do preprocess } */
/* { dg-options "-std=gnu89 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :)
CONCAT (::, >) /* { dg-error "does not give a valid preprocessing token" } */

8
gcc/testsuite/gcc.dg/cpp/gnu99-scope-1.c Normal file
View File

@ -0,0 +1,8 @@
/* Test :: token in gnu99. */
/* { dg-do preprocess } */
/* { dg-options "-std=gnu99 -pedantic-errors" } */
#define CONCAT(x, y) x ## y
CONCAT (:, :)
CONCAT (::, >) /* { dg-error "does not give a valid preprocessing token" } */

8
libcpp/ChangeLog
View File

@ -1,3 +1,11 @@
2019-10-02 Joseph Myers <joseph@codesourcery.com>
* include/cpplib.h (struct cpp_options): Add member scope.
* init.c (struct lang_flags, lang_defaults): Likewise.
(cpp_set_lang): Set scope member of pfile.
* lex.c (_cpp_lex_direct): Test CPP_OPTION (pfile, scope) not
CPP_OPTION (pfile, cplusplus) for creating CPP_SCOPE tokens.
2019-09-26 Eric Botcazou <ebotcazou@adacore.com>
* charset.c (UCS_LIMIT): New macro.

3
libcpp/include/cpplib.h
View File

@ -483,6 +483,9 @@ struct cpp_options
/* Nonzero for C++2a __VA_OPT__ feature. */
unsigned char va_opt;
/* Nonzero for the '::' token. */
unsigned char scope;
/* Holds the name of the target (execution) character set. */
const char *narrow_charset;

48
libcpp/init.c
View File

@ -92,32 +92,33 @@ struct lang_flags
char trigraphs;
char utf8_char_literals;
char va_opt;
char scope;
};
static const struct lang_flags lang_defaults[] =
{ /* c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt */
/* GNUC89 */ { 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1 },
/* GNUC99 */ { 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1 },
/* GNUC11 */ { 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1 },
/* GNUC17 */ { 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1 },
/* GNUC2X */ { 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1 },
/* STDC89 */ { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0 },
/* STDC94 */ { 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0 },
/* STDC99 */ { 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0 },
/* STDC11 */ { 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0 },
/* STDC17 */ { 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0 },
/* STDC2X */ { 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0 },
/* GNUCXX */ { 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1 },
/* CXX98 */ { 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0 },
/* GNUCXX11 */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1 },
/* CXX11 */ { 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0 },
/* GNUCXX14 */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1 },
/* CXX14 */ { 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0 },
/* GNUCXX17 */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1 },
/* CXX17 */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0 },
/* GNUCXX2A */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1 },
/* CXX2A */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1 },
/* ASM */ { 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
{ /* c99 c++ xnum xid c11 std digr ulit rlit udlit bincst digsep trig u8chlit vaopt scope*/
/* GNUC89 */ { 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1 },
/* GNUC99 */ { 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1 },
/* GNUC11 */ { 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1 },
/* GNUC17 */ { 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1 },
/* GNUC2X */ { 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1 },
/* STDC89 */ { 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0 },
/* STDC94 */ { 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0 },
/* STDC99 */ { 1, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0 },
/* STDC11 */ { 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0 },
/* STDC17 */ { 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0 },
/* STDC2X */ { 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1 },
/* GNUCXX */ { 0, 1, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1 },
/* CXX98 */ { 0, 1, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1 },
/* GNUCXX11 */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1 },
/* CXX11 */ { 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1 },
/* GNUCXX14 */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1 },
/* CXX14 */ { 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1 },
/* GNUCXX17 */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1 },
/* CXX17 */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1 },
/* GNUCXX2A */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1 },
/* CXX2A */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1 },
/* ASM */ { 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
};
/* Sets internal flags correctly for a given language. */
@ -143,6 +144,7 @@ cpp_set_lang (cpp_reader *pfile, enum c_lang lang)
CPP_OPTION (pfile, trigraphs) = l->trigraphs;
CPP_OPTION (pfile, utf8_char_literals) = l->utf8_char_literals;
CPP_OPTION (pfile, va_opt) = l->va_opt;
CPP_OPTION (pfile, scope) = l->scope;
}
/* Initialize library global state. */

2
libcpp/lex.c
View File

@ -3104,7 +3104,7 @@ _cpp_lex_direct (cpp_reader *pfile)
case ':':
result->type = CPP_COLON;
if (*buffer->cur == ':' && CPP_OPTION (pfile, cplusplus))
if (*buffer->cur == ':' && CPP_OPTION (pfile, scope))
buffer->cur++, result->type = CPP_SCOPE;
else if (*buffer->cur == '>' && CPP_OPTION (pfile, digraphs))
{