It's relatively common to cast a pointer to an unsigned long,
for example to make some bit operations.
It's much less sensicla to cast a pointer to an integer smaller
(or bigger) than a pointer is.
So allow to emit a diagnostic for this, under the control of a
new warning flag: -Wpointer-to-cast.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
lib.c | 2 ++
lib.h | 1 +
linearize.c | 5 +++++
validation/cast-kinds-check.c | 2 +-
validation/cast-kinds.c | 2 ++
5 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/lib.c b/lib.c
index 1c67e1912..7bfe9eb4e 100644
--- a/lib.c
+++ b/lib.c
@@ -241,6 +241,7 @@ int Woverride_init = 1;
int Woverride_init_all = 0;
int Woverride_init_whole_range = 0;
int Wparen_string = 0;
+int Wpointer_to_int_cast = 1;
int Wptr_subtraction_blows = 0;
int Wreturn_void = 0;
int Wshadow = 0;
@@ -532,6 +533,7 @@ static const struct warning {
{ "override-init", &Woverride_init },
{ "override-init-all", &Woverride_init_all },
{ "paren-string", &Wparen_string },
+ { "pointer-to-int-cast", &Wpointer_to_int_cast },
{ "ptr-subtraction-blows", &Wptr_subtraction_blows },
{ "return-void", &Wreturn_void },
{ "shadow", &Wshadow },
diff --git a/lib.h b/lib.h
index 010317970..e588bb8c5 100644
--- a/lib.h
+++ b/lib.h
@@ -134,6 +134,7 @@ extern int Woverride_init;
extern int Woverride_init_all;
extern int Woverride_init_whole_range;
extern int Wparen_string;
+extern int Wpointer_to_int_cast;
extern int Wptr_subtraction_blows;
extern int Wreturn_void;
extern int Wshadow;
diff --git a/linearize.c b/linearize.c
index a1b647864..cae402ad3 100644
--- a/linearize.c
+++ b/linearize.c
@@ -1246,6 +1246,11 @@ static pseudo_t cast_pseudo(struct entrypoint *ep, pseudo_t src, struct symbol *
src = cast_pseudo(ep, src, from, size_t_ctype);
from = size_t_ctype;
break;
+ case OP_PTRTU:
+ if (from->bit_size == to->bit_size)
+ break;
+ if (Wpointer_to_int_cast)
+ warning(to->pos, "non size-preserving pointer to integer cast");
default:
break;
}
diff --git a/validation/cast-kinds-check.c b/validation/cast-kinds-check.c
index 365fe6e40..0eb94d047 100644
--- a/validation/cast-kinds-check.c
+++ b/validation/cast-kinds-check.c
@@ -2,7 +2,7 @@
/*
* check-name: cast-kinds check
- * check-command: sparse -m64 -v $file
+ * check-command: sparse -m64 -v -Wno-pointer-to-int-cast $file
*
* check-error-start
cast-kinds.c:5:45: warning: cast drops bits
diff --git a/validation/cast-kinds.c b/validation/cast-kinds.c
index f60013e68..747a181ce 100644
--- a/validation/cast-kinds.c
+++ b/validation/cast-kinds.c
@@ -58,6 +58,8 @@ static double double_2_double(double a) { return a; }
* check-command: test-linearize -m64 $file
*
* check-error-start
+cast-kinds.c:8:41: warning: non size-preserving pointer to integer cast
+cast-kinds.c:15:43: warning: non size-preserving pointer to integer cast
cast-kinds.c:37:42: warning: non size-preserving integer to pointer cast
cast-kinds.c:38:44: warning: non size-preserving integer to pointer cast
* check-error-end
--
2.14.0
--
To unsubscribe from this list: send the line "unsubscribe linux-sparse" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
