EXP43-C: Add test case

Author: lcartey

c/cert/test/rules/EXP39-C/test.c

@@ -0,0 +1,81 @@
+void test_incompatible_arithmetic() {
+  float f = 0.0f;
+  int *p = (int *)&f; // NON_COMPLIANT - arithmetic types are not compatible
+                      // with each other
+  (*p)++;
+
+  short s[2];
+  (int *)&s; // NON_COMPLIANT
+
+  (short(*)[4]) & s; // NON_COMPLIANT - array of size 2 is not compatible with
+                     // array of size 4 (n1570 6.7.6.2 paragraph 7)
+  (short(*)[2]) & s; // COMPLIANT
+
+  // char may be signed or unsigned, and so is not compatible with either
+  char c1;
+  (signed char *)&c1;   // NON_COMPLIANT
+  (unsigned char *)&c1; // NON_COMPLIANT
+  (char *)&c1;          // NON_COMPLIANT
+
+  // int is defined as signed, so is compatible with all the signed versions
+  // (long, short etc. are similar)
+  int i1;
+  (signed int *)&i1;   // COMPLIANT
+  (int *)&i1;          // COMPLIANT
+  (signed *)&i1;       // COMPLIANT
+  (unsigned int *)&i1; // NON_COMPLIANT
+  (const int *)&i1;    // NON_COMPLIANT
+}
+
+struct {
+  int a;
+} * s1;
+struct {
+  int a;
+} * s2;
+struct S1 {
+  int a;
+} * s3;
+struct S1 *s4;
+
+// TODO test across files
+void test_incompatible_structs() {
+  // s1 and s2 do not have tags, and are therefore not compatible
+  s1 = s2; // NON_COMPLIANT
+  // s3 tag is inconsistent with s1 tag
+  s1 = s3; // NON_COMPLIANT
+  s3 = s1; // NON_COMPLIANT
+  // s4 tag is consistent with s3 tag
+  s3 = s4; // COMPLIANT
+  s4 = s3; // COMPLIANT
+}
+
+enum E1 { E1A, E1B };
+enum E2 { E2A, E2B };
+
+void test_enums() {
+  enum E1 e1 = E1A;
+  enum E2 e2 = e1; // COMPLIANT
+  // Enums are also compatible with one of `char`, a signed integer type or an
+  // unsigned integer type. It is implementation defined which is used, so
+  // choose an appropriate type below for this test
+  (int *)&e1; // COMPLIANT
+}
+
+int *void_cast(void *v) { return (int *)v; }
+
+void test_indirect_cast() {
+  float f1 = 0.0f;
+  void_cast(&f1); // NON_COMPLIANT
+  int i1 = 0;
+  void_cast(&i1); // COMPLIANT
+}
+
+signed f(int y) { return y; }
+int g(signed int x) { return x; }
+
+// 6.7.6.3 p15
+void test_compatible_functions() {
+  signed (*f1)(int) = &g;     // COMPLIANT
+  int (*g1)(signed int) = &f; // COMPLIANT
+}