Re: [PATCH] Null ctype should have ptr_ctype as its base type.

["Christopher Li" <sparse@chrisli.org>]

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On Sun, Dec 28, 2008 at 7:14 AM, Alexey Zaytsev
<alexey.zaytsev@gmail.com> wrote:

> So, we are getting a sizeof(NULL), or a sizeof((void *)0). It triggers here

That is my fault. My test for void type should have been more careful.

> because we are getting a null_ctype, and it's base_type points to
> void_ctype. I'm not sure if this patch is correct, but it seems to do
> the trick, all void warnings are gone. Christopher?

No, that is not the right way to fix it. Now you declare NULL as pointer
to a pointer type "(void**) 0".

Thanks for finding it out. Does my patch work for you?

Chris

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From a7b5de90ea3ea8485882ba348b045279709bd6d9 Mon Sep 17 00:00:00 2001
From: Christopher Li <sparse@chrisli.org>
Date: Sun, 28 Dec 2008 12:31:50 -0800
Subject: [PATCH] Correct testing for void type.

The last sizeof(void) warning commit too eager to
declare type is void. It end up sizeof(NULL) == 1
as well.

Signed-off-by: Christopher Li <sparse@chrisli.org>
---
 evaluate.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/evaluate.c b/evaluate.c
index d99d34f..2fff46e 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -337,6 +337,13 @@ static inline int is_byte_type(struct symbol *type)
 	return type->bit_size == bits_in_char && type->type != SYM_BITFIELD;
 }
 
+static inline int is_void_type(struct symbol *type)
+{
+	if (type->type == SYM_NODE)
+		type = type->ctype.base_type;
+	return type == &void_ctype;
+}
+
 enum {
 	TYPE_NUM = 1,
 	TYPE_BITFIELD = 2,
@@ -584,7 +591,7 @@ static struct symbol *evaluate_ptr_add(struct expression *expr, struct symbol *i
 	}
 
 	/* Get the size of whatever the pointer points to */
-	multiply = (base == &void_ctype) ? 1 : bits_to_bytes(base->bit_size);
+	multiply = is_void_type(base) ? 1 : bits_to_bytes(base->bit_size);
 
 	if (ctype == &null_ctype)
 		ctype = &ptr_ctype;
@@ -2050,7 +2057,7 @@ static struct symbol *evaluate_sizeof(struct expression *expr)
 
 	size = type->bit_size;
 
-	if (type->ctype.base_type == &void_ctype) {
+	if (size < 0 && is_void_type(type)) {
 		warning(expr->pos, "expression using sizeof(void)");
 		size = bits_in_char;
 	}
-- 
1.6.0.6