Add test for malloc

test/owic/stdlib/dune

@@ -0,0 +1,11 @@
+(rule
+ (alias runtest)
+ (deps
+  malloc_aligned.c
+  %{bin:owi}
+  (package owi)
+ )
+ (action
+  (run dune exec owi -- c ./malloc_aligned.c)
+ )
+)

test/owic/stdlib/malloc_aligned.c

@@ -0,0 +1,27 @@
+#include <owi.h>
+#include <stdlib.h>
+
+void arbitrary_pre_align() {
+    int s = owi_i32();
+    owi_assume(s >= 0);
+    owi_assume(s < 8);
+    for (int i = 0; i < s; i++) {
+        malloc(1);
+    }
+}
+
+int main() {
+    malloc(1024);
+    arbitrary_pre_align();
+    for (int p = 0; p < 10; p++) {
+        int low_pow = (1 << p);
+        for (int i = low_pow; i < 2*low_pow; i++) {
+            void * ptr = malloc(i);
+            if (low_pow < 16) {
+                owi_assert((int) ptr % low_pow == 0);
+            } else {
+                owi_assert((int) ptr % 16 == 0);
+            }
+        }
+    }
+}