[src/trunk]: src/usr.bin/xlint/lint1 lint: add support for C11 '_Atomic' as a...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/9eb91595acfc
branches:  trunk
changeset: 373151:9eb91595acfc
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sat Jan 21 13:48:40 2023 +0000

description:
lint: add support for C11 '_Atomic' as atomic-type-specifier

Following the C11 grammar, the keyword '_Atomic' needs to be a separate
syntactic category, to avoid further conflicts in the grammar.

The two newly added conflicts in the grammar would come into play when
mixing traditional C with C11, in a type name without an implicit 'int'.
If the type '_Atomic(int)*' were parsed as '_Atomic int(int)*', the
trailing '*' would be a syntax error.

diffstat:

 tests/usr.bin/xlint/lint1/c11_atomic.c |  11 +++++++++--
 tests/usr.bin/xlint/lint1/c99_atomic.c |  12 +++++++++++-
 usr.bin/xlint/lint1/cgram.y            |  30 +++++++++++++++++++++++-------
 usr.bin/xlint/lint1/lex.c              |   6 +++---
 4 files changed, 46 insertions(+), 13 deletions(-)

diffs (163 lines):

diff -r 9c1104eee610 -r 9eb91595acfc tests/usr.bin/xlint/lint1/c11_atomic.c
--- a/tests/usr.bin/xlint/lint1/c11_atomic.c    Sat Jan 21 13:07:21 2023 +0000
+++ b/tests/usr.bin/xlint/lint1/c11_atomic.c    Sat Jan 21 13:48:40 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: c11_atomic.c,v 1.2 2023/01/21 13:07:22 rillig Exp $    */
+/*     $NetBSD: c11_atomic.c,v 1.3 2023/01/21 13:48:40 rillig Exp $    */
 # 3 "c11_atomic.c"
 
 /*
@@ -19,4 +19,11 @@
        int field;
 } atomic_struct;
 
-/* TODO: C11 6.7.2.4 "Atomic type specifiers" */
+/* C11 6.7.2.4 "Atomic type specifiers" */
+double *
+atomic_ptr_cmpexch(_Atomic(double *)*ptr_var, _Atomic(double *) new_value)
+{
+       double *old = *ptr_var;
+       *ptr_var = new_value;
+       return old;
+}
diff -r 9c1104eee610 -r 9eb91595acfc tests/usr.bin/xlint/lint1/c99_atomic.c
--- a/tests/usr.bin/xlint/lint1/c99_atomic.c    Sat Jan 21 13:07:21 2023 +0000
+++ b/tests/usr.bin/xlint/lint1/c99_atomic.c    Sat Jan 21 13:48:40 2023 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: c99_atomic.c,v 1.2 2023/01/21 13:07:22 rillig Exp $    */
+/*     $NetBSD: c99_atomic.c,v 1.3 2023/01/21 13:48:40 rillig Exp $    */
 # 3 "c99_atomic.c"
 
 /*
@@ -13,3 +13,13 @@
 typedef _Atomic struct {
        int field;
 } atomic_struct;
+
+/* expect+3: error: '_Atomic' requires C11 or later [350] */
+/* expect+2: error: '_Atomic' requires C11 or later [350] */
+double *
+atomic_ptr_cmpexch(_Atomic(double *)*ptr_var, _Atomic(double *) new_value)
+{
+       double *old = *ptr_var;
+       *ptr_var = new_value;
+       return old;
+}
diff -r 9c1104eee610 -r 9eb91595acfc usr.bin/xlint/lint1/cgram.y
--- a/usr.bin/xlint/lint1/cgram.y       Sat Jan 21 13:07:21 2023 +0000
+++ b/usr.bin/xlint/lint1/cgram.y       Sat Jan 21 13:48:40 2023 +0000
@@ -1,5 +1,5 @@
 %{
-/* $NetBSD: cgram.y,v 1.430 2023/01/21 13:07:22 rillig Exp $ */
+/* $NetBSD: cgram.y,v 1.431 2023/01/21 13:48:40 rillig Exp $ */
 
 /*
  * Copyright (c) 1996 Christopher G. Demetriou.  All Rights Reserved.
@@ -35,7 +35,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID)
-__RCSID("$NetBSD: cgram.y,v 1.430 2023/01/21 13:07:22 rillig Exp $");
+__RCSID("$NetBSD: cgram.y,v 1.431 2023/01/21 13:48:40 rillig Exp $");
 #endif
 
 #include <limits.h>
@@ -143,7 +143,7 @@
 
 %}
 
-%expect 129
+%expect 131
 
 %union {
        val_t   *y_val;
@@ -206,8 +206,9 @@
  */
 %token <y_tspec>       T_TYPE
 
-/* qualifiers (const, volatile, restrict, _Thread_local, _Atomic) */
+/* qualifiers (const, volatile, restrict, _Thread_local) */
 %token <y_tqual>       T_QUAL
+%token <y_tqual>       T_ATOMIC
 
 /* struct or union */
 %token <y_tspec>       T_STRUCT_OR_UNION
@@ -276,6 +277,7 @@
 %type  <y_type>        begin_type_typespec
 %type  <y_type>        type_specifier
 %type  <y_type>        notype_type_specifier
+%type  <y_type>        atomic_type_specifier
 %type  <y_type>        struct_or_union_specifier
 %type  <y_tspec>       struct_or_union
 %type  <y_sym>         braced_struct_declaration_list
@@ -854,6 +856,7 @@
                $$ = $3 != NULL ? block_dup_type($3->tn_type) : gettyp(INT);
                $$->t_typeof = true;
          }
+       | atomic_type_specifier
        | struct_or_union_specifier {
                end_declaration_level();
                $$ = $1;
@@ -864,6 +867,13 @@
          }
        ;
 
+/* K&R ---, C90 ---, C99 ---, C11 6.7.2.4 */
+atomic_type_specifier:
+         atomic T_LPAREN type_name T_RPAREN {
+               $$ = $3;
+         }
+       ;
+
 struct_or_union_specifier:     /* C99 6.7.2.1 */
          struct_or_union identifier_sym {
                /*
@@ -1099,12 +1109,18 @@
        ;
 
 type_qualifier:                        /* C99 6.7.3 */
-         T_QUAL {
+         T_QUAL
+       | atomic {
+               $$ = ATOMIC;
+         }
+       ;
+
+atomic:                                /* helper */
+         T_ATOMIC {
                /* TODO: First fix c11ism, then use it here. */
-               if ($1 == ATOMIC && !allow_c11)
+               if (!allow_c11)
                        /* '_Atomic' requires C11 or later */
                        error(350);
-               $$ = $1;
          }
        ;
 
diff -r 9c1104eee610 -r 9eb91595acfc usr.bin/xlint/lint1/lex.c
--- a/usr.bin/xlint/lint1/lex.c Sat Jan 21 13:07:21 2023 +0000
+++ b/usr.bin/xlint/lint1/lex.c Sat Jan 21 13:48:40 2023 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: lex.c,v 1.141 2023/01/21 13:07:22 rillig Exp $ */
+/* $NetBSD: lex.c,v 1.142 2023/01/21 13:48:40 rillig Exp $ */
 
 /*
  * Copyright (c) 1996 Christopher G. Demetriou.  All Rights Reserved.
@@ -38,7 +38,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID)
-__RCSID("$NetBSD: lex.c,v 1.141 2023/01/21 13:07:22 rillig Exp $");
+__RCSID("$NetBSD: lex.c,v 1.142 2023/01/21 13:48:40 rillig Exp $");
 #endif
 
 #include <ctype.h>
@@ -112,7 +112,7 @@
        kwdef_keyword(  "_Alignas",     T_ALIGNAS),
        kwdef_keyword(  "_Alignof",     T_ALIGNOF),
        kwdef_token(    "alignof",      T_ALIGNOF,              78,0,6),
-       kwdef_tqual(    "_Atomic",      ATOMIC,                 11,0,1),
+       kwdef_token(    "_Atomic",      T_ATOMIC,               11,0,1),
        kwdef_token(    "asm",          T_ASM,                  78,1,7),
        kwdef_token(    "attribute",    T_ATTRIBUTE,            78,1,6),
        kwdef_sclass(   "auto",         AUTO,                   78,0,1),