linux-kernel - [PATCH V3] sparse: Allow override of sizeof(bool) warning

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Date:	Wed, 26 Feb 2014 19:19:25 -0800
From:	Joe Perches <joe@...ches.com>
To:	Josh Triplett <josh@...htriplett.org>
Cc:	"H. Peter Anvin" <hpa@...or.com>, linux-sparse@...r.kernel.org,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH V3] sparse: Allow override of sizeof(bool) warning

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>
---
v2: Add manpage
v3: gah.  Joe knows his alphabet (sometimes). (shadow _then_ sizeof)

 evaluate.c | 3 ++-
 lib.c      | 2 ++
 lib.h      | 1 +
 sparse.1   | 9 +++++++++
 4 files changed, 14 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 bf3e91c..d6ac79d 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 = 1;
 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..b7a5b5c 100644
--- a/sparse.1
+++ b/sparse.1
@@ -297,6 +297,15 @@ 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 issues these warnings by default.  To turn them off, use
+\fB\-Wno\-sizeof\-bool\fR.
+.
+.TP
 .B \-Wtransparent\-union
 Warn about any declaration using the GCC extension
 \fB__attribute__((transparent_union))\fR.
-- 
1.8.1.2.459.gbcd45b4.dirty



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