linux-kernel - Re: [PATCH V2] sparse: Allow override of sizeof(bool) warning

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Date:	Thu, 27 Feb 2014 12:44:37 -0800
From:	Christopher Li <sparse@...isli.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Ben Pfaff <blp@...ira.com>, Joe Perches <joe@...ches.com>,
	Josh Triplett <josh@...htriplett.org>,
	Linux-Sparse <linux-sparse@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2] sparse: Allow override of sizeof(bool) warning

On Thu, Feb 27, 2014 at 12:26 PM, H. Peter Anvin <hpa@...or.com> wrote:
> I would.
>

Joe, I assume you are OK with this patch, the default is now off.

Chris

Allow an override to emit or not the sizeof(bool) warning.
Add a "-Wsizeof-bool" description to the manpage.

Signed-off-by: Joe Perches <joe@...ches.com>
Reviewed-by: Josh Triplett <josh@...htriplett.org>
Signed-off-by: Christopher Li <sparse@...isli.org>
---
 evaluate.c | 3 ++-
 lib.c      | 2 ++
 lib.h      | 1 +
 sparse.1   | 8 ++++++++
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/evaluate.c b/evaluate.c
index 6655615..a45f59b 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -2057,7 +2057,8 @@ static struct symbol *evaluate_sizeof(struct
expression *expr)
     }

     if (size == 1 && is_bool_type(type)) {
-        warning(expr->pos, "expression using sizeof bool");
+        if (Wsizeof_bool)
+            warning(expr->pos, "expression using sizeof bool");
         size = bits_in_char;
     }

diff --git a/lib.c b/lib.c
index 51b97fd..844797d 100644
--- a/lib.c
+++ b/lib.c
@@ -226,6 +226,7 @@ int Wparen_string = 0;
 int Wptr_subtraction_blows = 0;
 int Wreturn_void = 0;
 int Wshadow = 0;
+int Wsizeof_bool = 0;
 int Wtransparent_union = 0;
 int Wtypesign = 0;
 int Wundef = 0;
@@ -438,6 +439,7 @@ static const struct warning {
     { "ptr-subtraction-blows", &Wptr_subtraction_blows },
     { "return-void", &Wreturn_void },
     { "shadow", &Wshadow },
+    { "sizeof-bool", &Wsizeof_bool },
     { "transparent-union", &Wtransparent_union },
     { "typesign", &Wtypesign },
     { "undef", &Wundef },
diff --git a/lib.h b/lib.h
index f09b338..f6cd9b4 100644
--- a/lib.h
+++ b/lib.h
@@ -120,6 +120,7 @@ extern int Wparen_string;
 extern int Wptr_subtraction_blows;
 extern int Wreturn_void;
 extern int Wshadow;
+extern int Wsizeof_bool;
 extern int Wtransparent_union;
 extern int Wtypesign;
 extern int Wundef;
diff --git a/sparse.1 b/sparse.1
index cd6be26..54da09b 100644
--- a/sparse.1
+++ b/sparse.1
@@ -297,6 +297,14 @@ Such declarations can lead to error-prone code.
 Sparse does not issue these warnings by default.
 .
 .TP
+.B \-Wsizeof-bool
+Warn when checking the sizeof a _Bool.
+
+C99 does not specify the sizeof a _Bool.  gcc uses 1.
+
+Sparse does not issue these warnings by default.
+.
+.TP
 .B \-Wtransparent\-union
 Warn about any declaration using the GCC extension
 \fB__attribute__((transparent_union))\fR.
-- 
1.8.5.3
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