This is quite similar to GCC's 'attribute(aligned(..))' but defined
as a new specifier and also accepting a typename as argument.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
parse.c | 43 +++++++++++++++++++++++++++++++++++++++++++
validation/c11-alignas.c | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 83 insertions(+)
create mode 100644 validation/c11-alignas.c
diff --git a/parse.c b/parse.c
index f131d0e6..6eca5686 100644
--- a/parse.c
+++ b/parse.c
@@ -128,6 +128,12 @@ static struct symbol_op noreturn_op = {
.declarator = noreturn_specifier,
};
+static declarator_t alignas_specifier;
+static struct symbol_op alignas_op = {
+ .type = KW_MODIFIER,
+ .declarator = alignas_specifier,
+};
+
static struct symbol_op auto_op = {
.type = KW_MODIFIER,
.declarator = auto_specifier,
@@ -440,6 +446,8 @@ static struct init_keyword {
{ "_Noreturn", NS_TYPEDEF, .op = &noreturn_op },
+ { "_Alignas", NS_TYPEDEF, .op = &alignas_op },
+
/* Ignored for now.. */
{ "restrict", NS_TYPEDEF, .op = &restrict_op},
{ "__restrict", NS_TYPEDEF, .op = &restrict_op},
@@ -1382,6 +1390,41 @@ static struct token *noreturn_specifier(struct token *next, struct decl_state *c
return next;
}
+static struct token *alignas_specifier(struct token *token, struct decl_state *ctx)
+{
+ int alignment = 0;
+
+ if (!match_op(token, '(')) {
+ sparse_error(token->pos, "expected '(' after _Alignas");
+ return token;
+ }
+ if (lookup_type(token->next)) {
+ struct symbol *sym = NULL;
+ token = typename(token->next, &sym, NULL);
+ sym = examine_symbol_type(sym);
+ alignment = sym->ctype.alignment;
+ token = expect(token, ')', "after _Alignas(...");
+ } else {
+ struct expression *expr = NULL;
+ token = parens_expression(token, &expr, "after _Alignas");
+ if (!expr)
+ return token;
+ alignment = const_expression_value(expr);
+ }
+
+ if (alignment < 0) {
+ warning(token->pos, "non-positive alignment");
+ return token;
+ }
+ if (alignment & (alignment-1)) {
+ warning(token->pos, "non-power-of-2 alignment");
+ return token;
+ }
+ if (alignment > ctx->ctype.alignment)
+ ctx->ctype.alignment = alignment;
+ return token;
+}
+
static struct token *const_qualifier(struct token *next, struct decl_state *ctx)
{
apply_qualifier(&next->pos, &ctx->ctype, MOD_CONST);
diff --git a/validation/c11-alignas.c b/validation/c11-alignas.c
new file mode 100644
index 00000000..4b264a5d
--- /dev/null
+++ b/validation/c11-alignas.c
@@ -0,0 +1,40 @@
+static _Alignas(8) int v;
+static _Alignas(long) int t;
+static _Alignas(void *) int p;
+static _Alignas(int[4]) int a;
+static _Alignas(0) int z;
+static _Alignas(3) int bnpow2;
+static _Alignas(-1) int bneg;
+static _Alignas(-2) int bnegpow2;
+static _Alignas(v) int bnc;
+static _Alignas(+) int bsyn;
+
+static int check(void)
+{
+ if (_Alignof(v) != 8)
+ return -1;
+ if (_Alignof(t) != _Alignof(long))
+ return -1;
+ if (_Alignof(p) != _Alignof(void *))
+ return -1;
+ if (_Alignof(a) != _Alignof(int))
+ return -1;
+
+ return 0;
+}
+
+/*
+ * check-name: c11-alignas
+ * check-command: test-linearize -std=c11 $file
+ *
+ * check-error-start
+c11-alignas.c:6:25: warning: non-power-of-2 alignment
+c11-alignas.c:7:25: warning: non-positive alignment
+c11-alignas.c:8:25: warning: non-positive alignment
+c11-alignas.c:9:17: error: bad constant expression
+c11-alignas.c:10:17: error: Syntax error in unary expression
+ * check-error-end
+ *
+ * check-output-ignore
+ * check-output-contains: ret\\.32 *\$0
+ */
--
2.11.0
--
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