evaluate: Allow sizeof(_Bool) to succeed.

Commit Message

Ben Pfaff May 4, 2011, 11:39 p.m. UTC

Without this commit, sizeof(_Bool) provokes an error with "cannot size
expression" because _Bool is a 1-bit type and thus not a multiple of a full
byte in size.  But sizeof(_Bool) is valid C that should evaluate to 1, so
this commit fixes the problem and adds a regression test.

Signed-off-by: Ben Pfaff <[e-mail]>
---
 evaluate.c               |    4 +++-
 symbol.h                 |    7 +++++++
 validation/sizeof-bool.c |    9 +++++++++
 3 files changed, 19 insertions(+), 1 deletions(-)
 create mode 100644 validation/sizeof-bool.c

Patch

diff --git a/evaluate.c b/evaluate.c
index f8343c2..f196dbc 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -2033,7 +2033,9 @@  static struct symbol *evaluate_sizeof(struct expression *expr)
 		size = bits_in_char;
 	}
 
-	if ((size < 0) || (size & (bits_in_char - 1)))
+	if (is_bool_type(type))
+		size = bits_in_char;
+	else if ((size < 0) || (size & (bits_in_char - 1)))
 		expression_error(expr, "cannot size expression");
 
 	expr->type = EXPR_VALUE;
diff --git a/symbol.h b/symbol.h
index e567305..2b8f20e 100644
--- a/symbol.h
+++ b/symbol.h
@@ -346,6 +346,13 @@  static inline int is_void_type(struct symbol *type)
 	return type == &void_ctype;
 }
 
+static inline int is_bool_type(struct symbol *type)
+{
+	if (type->type == SYM_NODE)
+		type = type->ctype.base_type;
+	return type == &bool_ctype;
+}
+
 static inline int is_function(struct symbol *type)
 {
 	return type && type->type == SYM_FN;
diff --git a/validation/sizeof-bool.c b/validation/sizeof-bool.c
new file mode 100644
index 0000000..dfcb12a
--- /dev/null
+++ b/validation/sizeof-bool.c
@@ -0,0 +1,9 @@ 
+static int a(void)
+{
+	return sizeof(_Bool);
+}
+/*
+ * check-name: sizeof(_Bool) is valid
+ * check-description: sizeof(_Bool) was rejected because _Bool is not an even
+ * number of bytes
+ */