--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang/utils/VtableTest/gen.cc	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,350 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define N_FIELDS 7
+#define N_FUNCS 128
+#define FUNCSPACING 20
+#define N_STRUCTS 180 /* 1280 */
+#define N_BASES 6
+#define COVARIANT 0
+
+const char *simple_types[] = { "bool", "char", "short", "int", "float",
+			       "double", "long double", "wchar_t", "void *",
+			       "char *"
+};
+
+void gl(const char *c) {
+  printf("%s\n", c);
+}
+
+void g(const char *c) {
+  printf("%s", c);
+}
+
+void g(int i) {
+  printf("%d", i);
+}
+
+int uuid = 0;
+char base_present[N_STRUCTS][N_STRUCTS];
+
+// The return type for each function when doing covariant testcase generation.
+short ret_types[N_STRUCTS][N_FUNCS*FUNCSPACING];
+
+bool is_ambiguous(int s, int base) {
+  for (int i = 0; i < N_STRUCTS; ++i) {
+    if ((base_present[base][i] & base_present[s][i]) == 1)
+      return true;
+  }
+  return false;
+}
+
+void add_bases(int s, int base) {
+  for (int i = 0; i < N_STRUCTS; ++i)
+    base_present[s][i] |= base_present[base][i];
+  if (!COVARIANT)
+    return;
+  for (int i = 0; i < N_FUNCS*FUNCSPACING; ++i) {
+    if (!ret_types[base][i])
+      continue;
+    if (!ret_types[s][i]) {
+      ret_types[s][i] = ret_types[base][i];
+      continue;
+    }
+    if (base_present[ret_types[base][i]][ret_types[s][i]])
+      // If the return type of the function from this base dominates
+      ret_types[s][i] = ret_types[base][i];
+    if (base_present[ret_types[s][i]][ret_types[base][i]])
+      // If a previous base dominates
+      continue;
+    // If neither dominates, we'll use this class.
+    ret_types[s][i] = s;
+  }
+}
+
+// This contains the class that has the final override for
+// each class, for each function.
+short final_override[N_STRUCTS][N_FUNCS*FUNCSPACING];
+
+void gs(int s) {
+  bool polymorphic = false;
+
+  static int bases[N_BASES];
+  int i_bases = random() % (N_BASES*2);
+  if (i_bases >= N_BASES)
+    // PARAM: 1/2 of all clases should have no bases
+    i_bases = 0;
+  int n_bases = 0;
+  bool first_base = true;
+  
+  // PARAM: 3/4 of all should be class, the rest are structs
+  if (random() % 4 == 0)
+    g("struct s");
+  else
+    g("class s");
+  g(s);
+  int old_base = -1;
+  if (s == 0 || s == 1)
+    i_bases = 0;
+  while (i_bases) {
+    --i_bases;
+    int base = random() % (s-1) + 1;
+    if (!base_present[s][base]) {
+      if (is_ambiguous(s, base))
+	continue;
+      if (first_base) {
+	first_base = false;
+	g(": ");
+      } else
+	g(", ");
+      int base_type = 1;
+      if (random()%8 == 0) {
+	// PARAM: 1/8th the bases are virtual
+	g("virtual ");
+        // We have a vtable and rtti, but technically we're not polymorphic
+	// polymorphic = true;
+	base_type = 3;
+      }
+      // PARAM: 1/4 are public, 1/8 are privare, 1/8 are protected, the reset, default
+      int base_protection = 0;
+      if (!COVARIANT)
+        base_protection = random()%8;
+      switch (base_protection) {
+      case 0:
+      case 1:
+	g("public "); break;
+      case 2:
+      case 3:
+      case 4:
+      case 5:
+	break;
+      case 6:
+	g("private "); break;
+      case 7:
+	g("protected "); break;
+      }
+      g("s");
+      add_bases(s, base);
+      bases[n_bases] = base;
+      base_present[s][base] = base_type;
+      ++n_bases;
+      g(base);
+      old_base = base;
+    }
+  }
+  gl(" {");
+
+  /* Fields */
+  int n_fields = N_FIELDS == 0 ? 0 : random() % (N_FIELDS*4);
+  // PARAM: 3/4 of all structs should have no members
+  if (n_fields >= N_FIELDS)
+    n_fields = 0;
+  for (int i = 0; i < n_fields; ++i) {
+    int t = random() % (sizeof(simple_types) / sizeof(simple_types[0]));
+    g("  "); g(simple_types[t]); g(" field"); g(i); gl(";");
+  }
+
+  /* Virtual functions */
+  static int funcs[N_FUNCS*FUNCSPACING];
+  // PARAM: 1/2 of all structs should have no virtual functions
+  int n_funcs = random() % (N_FUNCS*2);
+  if (n_funcs > N_FUNCS)
+    n_funcs = 0;
+  int old_func = -1;
+  for (int i = 0; i < n_funcs; ++i) {
+    int fn = old_func + random() % FUNCSPACING + 1;
+    funcs[i] = fn;
+    int ret_type = 0;
+    if (COVARIANT) {
+      ret_type = random() % s + 1;
+      if (!base_present[s][ret_type]
+          || !base_present[ret_type][ret_types[s][fn]])
+        if (ret_types[s][fn]) {
+          printf("  // Found one for s%d for s%d* fun%d.\n", s,
+                 ret_types[s][fn], fn);
+          ret_type = ret_types[s][fn];
+        } else
+          ret_type = s;
+      else
+        printf("  // Wow found one for s%d for fun%d.\n", s, fn);
+      ret_types[s][fn] = ret_type;
+    }
+    if (ret_type) {
+      g("  virtual s"); g(ret_type); g("* fun");
+    } else
+      g("  virtual void fun");
+    g(fn); g("(char *t) { mix(\"vfn this offset\", (char *)this - t); mix(\"vfn uuid\", "); g(++uuid);
+    if (ret_type)
+      gl("); return 0; }");
+    else
+      gl("); }");
+    final_override[s][fn] = s;
+    old_func = fn;
+  }
+
+  // Add required overriders for correctness
+  for (int i = 0; i < n_bases; ++i) {
+    // For each base
+    int base = bases[i];
+    for (int fn = 0; fn < N_FUNCS*FUNCSPACING; ++fn) {
+      // For each possible function
+      int new_base = final_override[base][fn];
+      if (new_base == 0)
+        // If the base didn't have a final overrider, skip
+        continue;
+
+      int prev_base = final_override[s][fn];
+      if (prev_base == s)
+        // Skip functions defined in this class
+        continue;
+
+      // If we don't want to change the info, skip
+      if (prev_base == new_base)
+        continue;
+      
+      if (prev_base == 0) {
+        // record the final override
+        final_override[s][fn] = new_base;
+        continue;
+      }
+        
+      if (base_present[prev_base][new_base]) {
+        // The previous base dominates the new base, no update necessary
+        printf("  // No override for fun%d in s%d as s%d dominates s%d.\n",
+               fn, s, prev_base, new_base);
+        continue;
+      }
+
+      if (base_present[new_base][prev_base]) {
+        // The new base dominates the old base, no override necessary
+        printf("  // No override for fun%d in s%d as s%d dominates s%d.\n",
+               fn, s, new_base, prev_base);
+        // record the final override
+        final_override[s][fn] = new_base;
+        continue;
+      }
+
+      printf("  // Found we needed override for fun%d in s%d.\n", fn, s);
+
+      // record the final override
+      funcs[n_funcs++] = fn;
+      if (n_funcs == (N_FUNCS*FUNCSPACING-1))
+        abort();
+      int ret_type = 0;
+      if (COVARIANT) {
+        if (!ret_types[s][fn]) {
+          ret_types[s][fn] = ret_type = s;
+        } else {
+          ret_type = ret_types[s][fn];
+          if (ret_type != s)
+            printf("  // Calculated return type in s%d as s%d* fun%d.\n",
+                   s, ret_type, fn);
+        }
+      }
+      if (ret_type) {
+        g("  virtual s"); g(ret_type); g("* fun");
+      } else
+        g("  virtual void fun");
+      g(fn); g("(char *t) { mix(\"vfn this offset\", (char *)this - t); mix(\"vfn uuid\", "); g(++uuid);
+      if (ret_type)
+        gl("); return 0; }");
+      else
+        gl("); }");
+      final_override[s][fn] = s;
+    }
+  }
+
+  gl("public:");
+  gl("  void calc(char *t) {");
+
+  // mix in the type number
+  g("    mix(\"type num\", "); g(s); gl(");");
+  // mix in the size
+  g("    mix(\"type size\", sizeof (s"); g(s); gl("));");
+  // mix in the this offset
+  gl("    mix(\"subobject offset\", (char *)this - t);");
+  if (n_funcs)
+    polymorphic = true;
+  if (polymorphic) {
+    // mix in offset to the complete object under construction
+    gl("    mix(\"real top v current top\", t - (char *)dynamic_cast<void*>(this));");
+  }
+
+  /* check base layout and overrides */
+  for (int i = 0; i < n_bases; ++i) {
+    g("    calc_s"); g(bases[i]); gl("(t);");
+  }
+
+  if (polymorphic) {
+    /* check dynamic_cast to each direct base */
+    for (int i = 0; i < n_bases; ++i) {
+      g("    if ((char *)dynamic_cast<s"); g(bases[i]); gl("*>(this))");
+      g("      mix(\"base dyn cast\", t - (char *)dynamic_cast<s"); g(bases[i]); gl("*>(this));");
+      g("    else mix(\"no dyncast\", "); g(++uuid); gl(");");
+    }
+  }
+
+  /* check field layout */
+  for (int i = 0; i < n_fields; ++i) {
+    g("    mix(\"field offset\", (char *)&field"); g(i); gl(" - (char *)this);");
+  }
+  if (n_fields == 0) {
+    g("    mix(\"no fields\", "); g(++uuid); gl(");");
+  }
+
+  /* check functions */
+  for (int i = 0; i < n_funcs; ++i) {
+    g("    fun"); g(funcs[i]); gl("(t);");
+  }
+  if (n_funcs == 0) {
+    g("    mix(\"no funcs\", "); g(++uuid); gl(");");
+  }
+
+  gl("  }");
+
+  // default ctor
+  g("  s"); g(s); g("() ");
+  first_base = true;
+  for (int i = 0; i < n_bases; ++i) {
+    if (first_base) {
+      g(": ");
+      first_base = false;
+    } else
+      g(", ");
+    g("s"); g(bases[i]); g("((char *)this)");
+  }
+  gl(" { calc((char *)this); }");
+  g("  ~s"); g(s); gl("() { calc((char *)this); }");
+
+ // ctor with this to the complete object
+  g("  s"); g(s); gl("(char *t) { calc(t); }");
+  g("  void calc_s"); g(s); gl("(char *t) { calc(t); }");
+  g("} a"); g(s); gl(";");
+}
+
+main(int argc, char **argv) {
+  unsigned seed = 0;
+  char state[16];
+  if (argc > 1)
+    seed = atol(argv[1]);
+
+  initstate(seed, state, sizeof(state));
+  gl("extern \"C\" int printf(const char *...);");
+  gl("");
+  gl("long long sum;");
+  gl("void mix(const char *desc, long long i) {");
+  // If this ever becomes too slow, we can remove this after we improve the
+  // mixing function
+  gl("  printf(\"%s: %lld\\n\", desc, i);");
+  gl("  sum += ((sum ^ i) << 3) + (sum<<1) - i;");
+  gl("}");
+  gl("");
+  // PARAM: Randomly size testcases or large testcases?
+  int n_structs = /* random() % */ N_STRUCTS;
+  for (int i = 1; i < n_structs; ++i)
+    gs(i);
+  gl("int main() {");
+  gl("  printf(\"%llx\\n\", sum);");
+  gl("}");
+  return 0;
+}