The current code detects and warns on division by zero but
only when the left-hand side is a constant value.
Fix that by moving up the code which detect such divisions
before checking if the LHS is a constant.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
expand.c | 8 ++----
validation/div-by-zero.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 68 insertions(+), 6 deletions(-)
create mode 100644 validation/div-by-zero.c
diff --git a/expand.c b/expand.c
index 5f908c971..0b528ea5a 100644
--- a/expand.c
+++ b/expand.c
@@ -181,6 +181,8 @@ static int simplify_int_binop(struct expression *expr, struct symbol *ctype)
if (right->type != EXPR_VALUE)
return 0;
r = right->value;
+ if (!r && (expr->op == '/' || expr->op == '%'))
+ goto Div;
if (expr->op == SPECIAL_LEFTSHIFT || expr->op == SPECIAL_RIGHTSHIFT) {
if (r >= ctype->bit_size) {
if (conservative)
@@ -235,28 +237,22 @@ static int simplify_int_binop(struct expression *expr, struct symbol *ctype)
break;
case SIGNED('/'):
- if (!r)
- goto Div;
if (l == mask && sr == -1)
goto Overflow;
v = sl / sr;
break;
case UNSIGNED('/'):
- if (!r) goto Div;
v = l / r;
break;
case SIGNED('%'):
- if (!r)
- goto Div;
if (l == mask && sr == -1)
goto Overflow;
v = sl % sr;
break;
case UNSIGNED('%'):
- if (!r) goto Div;
v = l % r;
break;
diff --git a/validation/div-by-zero.c b/validation/div-by-zero.c
new file mode 100644
index 000000000..500ceb8eb
--- /dev/null
+++ b/validation/div-by-zero.c
@@ -0,0 +1,66 @@
+int scdiv(int a) { return 2 / 0; }
+int iscdiv(int a) { return 2 / (int) 0; }
+int lscdiv(int a) { return 2 / (long) 0; }
+int uscdiv(int a) { return 2 / (unsigned int) 0; }
+
+int svdiv(int a) { return a / 0; }
+int isvdiv(int a) { return a / (int) 0; }
+int lsvdiv(int a) { return a / (long) 0; }
+int usvdiv(int a) { return a / (unsigned int) 0; }
+
+int scmod(int a) { return 2 % 0; }
+int iscmod(int a) { return 2 % (int) 0; }
+int lscmod(int a) { return 2 % (long) 0; }
+int uscmod(int a) { return 2 % (unsigned int) 0; }
+
+int svmod(int a) { return a % 0; }
+int isvmod(int a) { return a % (int) 0; }
+int lsvmod(int a) { return a % (long) 0; }
+int usvmod(int a) { return a % (unsigned int) 0; }
+
+int xsvdiv(int a) { if (a && 0) return a / 0; return 0; }
+int asvdiv(int a) { return a /= 0; }
+int osvdiv(int a) { return a / (a && 0); }
+
+int xsvmod(int a) { if (a && 0) return a % 0; return 0; }
+int asvmod(int a) { return a %= 0; }
+int osvmod(int a) { return a % (a && 0); }
+
+int ysvdiv(int a) { if (a && 0) return a /= 0; return 0; }
+int ysvmod(int a) { if (a && 0) return a %= 0; return 0; }
+
+int zsvdiv(int a) { if (0 && (a / 0)) return 1; return 0; }
+int zsvmod(int a) { if (0 && (a /= 0)) return 1; return 0; }
+
+int wsvdiv(int a) { if (0) return a / 0; return 0; }
+int wsvmod(int a) { if (0) return a % 0; return 0; }
+int vsvdiv(int a) { if (0) return a /= 0; return 0; }
+int vsvmod(int a) { if (0) return a %= 0; return 0; }
+
+/*
+ * check-name: div-by-zero.c
+ * check-command: sparse -Wno-decl $file
+ *
+ * check-error-start
+div-by-zero.c:1:30: warning: division by zero
+div-by-zero.c:2:30: warning: division by zero
+div-by-zero.c:3:30: warning: division by zero
+div-by-zero.c:4:30: warning: division by zero
+div-by-zero.c:6:30: warning: division by zero
+div-by-zero.c:7:30: warning: division by zero
+div-by-zero.c:8:30: warning: division by zero
+div-by-zero.c:9:30: warning: division by zero
+div-by-zero.c:11:30: warning: division by zero
+div-by-zero.c:12:30: warning: division by zero
+div-by-zero.c:13:30: warning: division by zero
+div-by-zero.c:14:30: warning: division by zero
+div-by-zero.c:16:30: warning: division by zero
+div-by-zero.c:17:30: warning: division by zero
+div-by-zero.c:18:30: warning: division by zero
+div-by-zero.c:19:30: warning: division by zero
+div-by-zero.c:21:42: warning: division by zero
+div-by-zero.c:25:42: warning: division by zero
+div-by-zero.c:35:37: warning: division by zero
+div-by-zero.c:36:37: warning: division by zero
+ * check-error-end
+ */
--
2.13.0
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