Migrate loop contracts regressions to dfcc

Author: qinheping

regression/contracts-dfcc/detect_loop_locals/main.c

@@ -0,0 +1,12 @@
+#include <stdlib.h>
+
+int main()
+{
+  unsigned char *i = malloc(5);
+
+  while(i != i + 5)
+    __CPROVER_loop_invariant(1 == 1)
+    {
+      const char lower = *i++;
+    }
+}

regression/contracts-dfcc/detect_loop_locals/test.desc

@@ -0,0 +1,10 @@
+CORE
+main.c
+--dfcc main --apply-loop-contracts
+^\[main.assigns.\d+\].*line 10 Check that i is assignable: SUCCESS$
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
+--
+Checks that loop local variables do not cause explicit checks.

regression/contracts-dfcc/detect_loop_locals2/main.c

@@ -0,0 +1,28 @@
+static void foo()
+{
+  unsigned i;
+
+  for(i = 0; i < 16; i++)
+    __CPROVER_loop_invariant(1 == 1)
+    {
+      int v = 1;
+    }
+}
+
+static void bar()
+{
+  unsigned i;
+
+  for(i = 0; i < 16; i++)
+    __CPROVER_loop_invariant(1 == 1)
+    {
+      int v = 1;
+    }
+}
+
+int main()
+{
+  bar();
+  foo();
+  foo();
+}

regression/contracts-dfcc/detect_loop_locals2/test.desc

@@ -0,0 +1,11 @@
+CORE
+main.c
+--dfcc main --apply-loop-contracts
+^\[bar.assigns.\d+\].*Check that i is assignable: SUCCESS$
+^\[foo.assigns.\d+\].*Check that i is assignable: SUCCESS$
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
+--
+Checks that loop local variables do not cause explicit checks 

regression/contracts-dfcc/github_6168_infinite_unwinding_bug/main.c

@@ -0,0 +1,21 @@
+#include <assert.h>
+#include <stdlib.h>
+
+static int adder(const int *a, const int *b)
+{
+  return (*a + *b);
+}
+
+int main()
+{
+  int x = 1024;
+
+  int (*local_adder)(const int *, const int *) = adder;
+
+  while(x > 0)
+    __CPROVER_loop_invariant(1 == 1)
+    {
+      x += local_adder(&x, &x); // loop detection fails
+      //x += adder(&x, &x);       // works fine
+    }
+}

regression/contracts-dfcc/github_6168_infinite_unwinding_bug/test.desc

@@ -0,0 +1,11 @@
+CORE
+main.c
+--dfcc main --apply-loop-contracts
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+^\[main.\d+\] line \d+ Check loop invariant before entry: SUCCESS$
+^\[main.\d+\] line \d+ Check that loop invariant is preserved: SUCCESS$
+--
+--
+This is guarding against an issue described in https://github.com/diffblue/cbmc/issues/6168.

regression/contracts-dfcc/history-index/main.c

@@ -0,0 +1,14 @@
+#include <assert.h>
+
+int main()
+{
+  int i, n, x[10];
+  __CPROVER_assume(x[0] == x[9]);
+  while(i < n)
+    __CPROVER_loop_invariant(x[0] == __CPROVER_loop_entry(x[0]))
+    {
+      x[0] = x[9] - 1;
+      x[0]++;
+    }
+  assert(x[0] == x[9]);
+}

regression/contracts-dfcc/history-index/test.desc

@@ -0,0 +1,10 @@
+CORE
+main.c
+--dfcc main --apply-loop-contracts
+^EXIT=0$
+^SIGNAL=0$
+^VERIFICATION SUCCESSFUL$
+--
+^Tracking history of index expressions is not supported yet\.
+--
+This test checks that `ID_index` expressions are allowed within history variables.

regression/contracts-dfcc/history-invalid/main.c

@@ -0,0 +1,19 @@
+#include <assert.h>
+
+int foo(int x)
+{
+  return x;
+}
+
+int main()
+{
+  int i, n, x[10];
+  __CPROVER_assume(x[0] == x[9]);
+  while(i < n)
+    __CPROVER_loop_invariant(x[0] == __CPROVER_loop_entry(foo(x[0])))
+    {
+      x[0] = x[9] - 1;
+      x[0]++;
+    }
+  assert(x[0] == x[9]);
+}

regression/contracts-dfcc/history-invalid/test.desc

@@ -0,0 +1,11 @@
+CORE
+main.c
+--dfcc --apply-loop-contracts
+^main.c.* error: Tracking history of side_effect expressions is not supported yet.$
+^CONVERSION ERROR$
+^EXIT=(1|64)$
+^SIGNAL=0$
+--
+--
+This test ensures that expressions with side effect, such as function calls,
+may not be used in history variables.