7 files changed, 156 insertions, 0 deletions
diff --git a/evaluate.c b/evaluate.c
index edace120..7d2dc516 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -2211,6 +2211,38 @@ static struct symbol *evaluate_sizeof(struct expression *expr)
 		size = bits_in_char;
 	}
 
+	if (is_array_type(type) && size < 0) {	// VLA, 1-dimension only
+		struct expression *base, *size;
+		struct symbol *base_type;
+
+		if (type->type == SYM_NODE)
+			type = type->ctype.base_type;	// strip the SYM_NODE
+		base_type = get_base_type(type);
+		if (!base_type)
+			goto error;
+		if (base_type->bit_size <= 0) {
+			base = alloc_expression(expr->pos, EXPR_SIZEOF);
+			base->cast_type = base_type;
+			if (!evaluate_sizeof(base))
+				goto error;
+		} else {
+			base = alloc_expression(expr->pos, EXPR_VALUE);
+			base->value = bits_to_bytes(base_type->bit_size);
+			base->ctype = size_t_ctype;
+		}
+		size = alloc_expression(expr->pos, EXPR_CAST);
+		size->cast_type = size_t_ctype;
+		size->cast_expression = type->array_size;
+		if (!evaluate_expression(size))
+			goto error;
+		expr->left = size;
+		expr->right = base;
+		expr->type = EXPR_BINOP;
+		expr->op = '*';
+		return expr->ctype = size_t_ctype;
+	}
+
+error:
 	if ((size < 0) || (size & (bits_in_char - 1)))
 		expression_error(expr, "cannot size expression");
 
diff --git a/validation/vla-sizeof-ice.c b/validation/vla-sizeof-ice.c
new file mode 100644
index 00000000..472da6a4
--- /dev/null
+++ b/validation/vla-sizeof-ice.c
@@ -0,0 +1,19 @@
+// credit goes to Martin Uecker for the awesome ICE_P macro
+
+#define ICE_P(x) \
+    (__builtin_types_compatible_p(typeof(0?((void*)((long)(x)*0l)):(int*)1),int*))
+
+#define T(x)		__builtin_choose_expr(ICE_P(x), 1, 0)
+#define TEST(x, r)	_Static_assert(T(x) == r, #x " => " #r)
+
+static void test(int n)
+{
+	char foo[n++];
+
+	TEST(sizeof(foo), 0);
+}
+
+/*
+ * check-name: vla-sizeof-ice
+ * check-command: sparse -Wno-vla $file
+ */
diff --git a/validation/vla-sizeof0.c b/validation/vla-sizeof0.c
new file mode 100644
index 00000000..a58fd300
--- /dev/null
+++ b/validation/vla-sizeof0.c
@@ -0,0 +1,20 @@
+#define N 2
+#define T int
+
+static unsigned int foo(int x)
+{
+	T a[(1,N)];
+
+	return sizeof(a) == (N * sizeof(T));
+}
+
+/*
+ * check-name: vla-sizeof cte,cte
+ * check-command: test-linearize -Wvla $file
+ *
+ * check-output-ignore
+ * check-output-contains: ret\\.32 *\\$1
+ *
+ * check-error-start
+ * check-error-end
+ */
diff --git a/validation/vla-sizeof1.c b/validation/vla-sizeof1.c
new file mode 100644
index 00000000..ed7f5d4e
--- /dev/null
+++ b/validation/vla-sizeof1.c
@@ -0,0 +1,21 @@
+#define N 2
+#define T int
+
+static unsigned int foo(int x)
+{
+	T a[(x,N)];
+
+	return sizeof(a) == (N * sizeof(T));
+}
+
+/*
+ * check-name: vla-sizeof var,cte
+ * check-command: test-linearize -Wvla $file
+ *
+ * check-output-ignore
+ * check-output-contains: ret\\.32 *\\$1
+ *
+ * check-error-start
+vla-sizeof1.c:6:15: warning: Variable length array is used.
+ * check-error-end
+ */
diff --git a/validation/vla-sizeof2.c b/validation/vla-sizeof2.c
new file mode 100644
index 00000000..57927d16
--- /dev/null
+++ b/validation/vla-sizeof2.c
@@ -0,0 +1,21 @@
+#define N 2
+#define T int
+
+static unsigned long foo(int x)
+{
+	T a[x];
+
+	return sizeof(a) == (x * sizeof(T));
+}
+
+/*
+ * check-name: vla-sizeof var
+ * check-command: test-linearize -Wvla $file
+ *
+ * check-output-ignore
+ * check-output-contains: ret\\..*\\$1
+ *
+ * check-error-start
+vla-sizeof2.c:6:13: warning: Variable length array is used.
+ * check-error-end
+ */
diff --git a/validation/vla-sizeof3.c b/validation/vla-sizeof3.c
new file mode 100644
index 00000000..21edb007
--- /dev/null
+++ b/validation/vla-sizeof3.c
@@ -0,0 +1,21 @@
+#define N 2UL
+#define T int
+
+static unsigned long foo(int x)
+{
+	T a[x][N];
+
+	return sizeof(a) == (N * x * sizeof(T));
+}
+
+/*
+ * check-name: vla-sizeof var X cte
+ * check-command: test-linearize -Wvla $file
+ *
+ * check-output-ignore
+ * check-output-contains: ret\\..*\\$1
+ *
+ * check-error-start
+vla-sizeof3.c:6:13: warning: Variable length array is used.
+ * check-error-end
+ */
diff --git a/validation/vla-sizeof4.c b/validation/vla-sizeof4.c
new file mode 100644
index 00000000..e7478613
--- /dev/null
+++ b/validation/vla-sizeof4.c
@@ -0,0 +1,22 @@
+#define N 2
+#define T int
+
+static unsigned long foo(int x, int y)
+{
+	T a[x][y];
+
+	return sizeof(a) == (x * (y * sizeof(T)));
+}
+
+/*
+ * check-name: vla-sizeof var X var
+ * check-command: test-linearize -Wvla $file
+ *
+ * check-output-ignore
+ * check-output-contains: ret\\..*\\$1
+ *
+ * check-error-start
+vla-sizeof4.c:6:16: warning: Variable length array is used.
+vla-sizeof4.c:6:13: warning: Variable length array is used.
+ * check-error-end
+ */