Avoid evaluating INT_MIN / -1 and INT_MIN % -1, which will trap on x86
and crash sparse.
Signed-off-by: Xi Wang <xi.wang@xxxxxxxxx>
---
expand.c | 2 ++
simplify.c | 4 ++++
validation/div.c | 29 +++++++++++++++++++++++++++++
3 files changed, 35 insertions(+)
create mode 100644 validation/div.c
diff --git a/expand.c b/expand.c
index effd27b..2dfa5e5 100644
--- a/expand.c
+++ b/expand.c
@@ -239,6 +239,8 @@ static int simplify_int_binop(struct expression *expr, struct symbol *ctype)
case SIGNED('%'):
if (!r)
goto Div;
+ if (l == mask && sr == -1)
+ goto Overflow;
v = sl % sr;
break;
diff --git a/simplify.c b/simplify.c
index bda4a5b..b5cd0ea 100644
--- a/simplify.c
+++ b/simplify.c
@@ -406,6 +406,8 @@ static int simplify_constant_binop(struct instruction *insn)
case OP_DIVS:
if (!right)
return 0;
+ if (left == mask && right == -1)
+ return 0;
res = left / right;
break;
case OP_MODU:
@@ -416,6 +418,8 @@ static int simplify_constant_binop(struct instruction *insn)
case OP_MODS:
if (!right)
return 0;
+ if (left == mask && right == -1)
+ return 0;
res = left % right;
break;
case OP_SHL:
diff --git a/validation/div.c b/validation/div.c
new file mode 100644
index 0000000..3dcbfd5
--- /dev/null
+++ b/validation/div.c
@@ -0,0 +1,29 @@
+#include <limits.h>
+
+static int xd = 1 / 0;
+static int xl = 1L / 0;
+static int xll = 1LL / 0;
+
+static int yd = INT_MIN / -1;
+static long yl = LONG_MIN / -1;
+static long long yll = LLONG_MIN / -1;
+
+static int zd = INT_MIN % -1;
+static long zl = LONG_MIN % -1;
+static long long zll = LLONG_MIN % -1;
+
+/*
+ * check-name: division constants
+ *
+ * check-error-start
+div.c:3:19: warning: division by zero
+div.c:4:20: warning: division by zero
+div.c:5:22: warning: division by zero
+div.c:7:25: warning: constant integer operation overflow
+div.c:8:27: warning: constant integer operation overflow
+div.c:9:34: warning: constant integer operation overflow
+div.c:11:25: warning: constant integer operation overflow
+div.c:12:27: warning: constant integer operation overflow
+div.c:13:34: warning: constant integer operation overflow
+ * check-error-end
+ */
--
1.8.1.2
--
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
