Hello Mauro/Hans!
> There is already an upstream patch for hidding it:
The patch from https://patchwork.kernel.org/patch/10334353 will not
apply at the smatch tree.
Attached is an updated version for smatch.
Even with the patched tools, sparse still complains:
CC drivers/media/cec/cec-core.o
/opt/media_test/media-git/include/linux/mm.h:533:24: warning: constant 0xffffc90000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:533:48: warning: constant 0xffffc90000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:624:29: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:1098:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:1795:27: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:1887:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/scatterlist.h:151:25: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/scatterlist.h:236:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/scatterlist.h:387:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/scatterlist.h:387:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/dma-mapping.h:235:35: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/dma-mapping.h:238:33: warning: constant 0xffffea0000000000 is so big it is unsigned long
CC drivers/media/usb/gspca/gl860/gl860-mi2020.o
/opt/media_test/media-git/include/linux/mm.h:533:24: warning: constant 0xffffc90000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:533:48: warning: constant 0xffffc90000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:624:29: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:1098:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:1795:27: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/mm.h:1887:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/scatterlist.h:151:25: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/scatterlist.h:236:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/scatterlist.h:387:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
/opt/media_test/media-git/include/linux/scatterlist.h:387:16: warning: constant 0xffffea0000000000 is so big it is unsigned long
But other warnings are gone with the patch.
The daily build is running on a machine of Hans. He need to update the
tools there.
@Hans:
Until this patches are in upstream, we need to patch smatch/sparse on the fly
in build.sh after pulling the last tools version.
BR,
Jasmin
diff --git a/evaluate.c b/evaluate.c
index 1533730..815e7e1 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -2090,7 +2090,8 @@ static struct symbol *evaluate_sizeof(struct expression *expr)
size = type->bit_size;
if (size < 0 && is_void_type(type)) {
- warning(expr->pos, "expression using sizeof(void)");
+ if (Wpointer_arith)
+ warning(expr->pos, "expression using sizeof(void)");
size = bits_in_char;
}
@@ -2101,7 +2102,8 @@ static struct symbol *evaluate_sizeof(struct expression *expr)
}
if (is_function(type->ctype.base_type)) {
- warning(expr->pos, "expression using sizeof on a function");
+ if (Wpointer_arith)
+ warning(expr->pos, "expression using sizeof on a function");
size = bits_in_char;
}
diff --git a/lib.c b/lib.c
index 69b5ab8..ed4a74f 100644
--- a/lib.c
+++ b/lib.c
@@ -234,6 +234,7 @@ int Wnon_pointer_null = 1;
int Wold_initializer = 1;
int Wone_bit_signed_bitfield = 1;
int Wparen_string = 0;
+int Wpointer_arith = 0;
int Wptr_subtraction_blows = 0;
int Wreturn_void = 0;
int Wshadow = 0;
@@ -453,6 +454,7 @@ static const struct warning {
{ "return-void", &Wreturn_void },
{ "shadow", &Wshadow },
{ "sizeof-bool", &Wsizeof_bool },
+ { "pointer-arith", &Wpointer_arith },
{ "transparent-union", &Wtransparent_union },
{ "typesign", &Wtypesign },
{ "undef", &Wundef },
diff --git a/lib.h b/lib.h
index 0838342..a86615b 100644
--- a/lib.h
+++ b/lib.h
@@ -120,6 +120,7 @@ extern int Wnon_pointer_null;
extern int Wold_initializer;
extern int Wone_bit_signed_bitfield;
extern int Wparen_string;
+extern int Wpointer_arith;
extern int Wptr_subtraction_blows;
extern int Wreturn_void;
extern int Wshadow;
diff --git a/sparse.1 b/sparse.1
index acdce53..53eff87 100644
--- a/sparse.1
+++ b/sparse.1
@@ -265,6 +265,19 @@ initializer. GCC allows this syntax as an extension. With
Sparse does not issue these warnings by default.
.
.TP
+.B \-Wpointer\-arith
+Warn about anything that depends on the \fBsizeof\fR a void or function type.
+
+C99 does not allow the \fBsizeof\fR operator to be applied to function types
+or to incomplete types such as void. GCC allows \fBsizeof\fR to be applied to
+these types as an extension and assigns these types a size of \fI1\fR. With
+\fB\-pointer\-arith\fR, Sparse will warn about pointer arithmetic on void
+or function pointers, as well as expressions which directly apply the
+\fBsizeof\fR operator to void or function types.
+
+Sparse does not issue these warnings by default.
+.
+.TP
.B \-Wptr\-subtraction\-blows
Warn when subtracting two pointers to a type with a non-power-of-two size.
