// RUN: %clang_cc1 -std=c++20 -verify %s

namespace std {
  typedef decltype(sizeof(int)) size_t;

  template <class E> struct initializer_list {
    const E *data;
    size_t size;

    constexpr initializer_list(const E *data, size_t size)
        : data(data), size(size) {}
    constexpr initializer_list() : data(), size() {}

    constexpr const E *begin() const { return data; }
    constexpr const E *end() const { return data + size; }
  };
}

struct ConstexprString {
  constexpr ConstexprString() : ConstexprString("") {}
  constexpr ConstexprString(const char *p, std::size_t size) : data(new char[size+1]) {
    __builtin_memcpy(data, p, size);
    data[size] = '\0';
  }
  constexpr ConstexprString(const char *p) : ConstexprString(p, __builtin_strlen(p)) {}
  constexpr explicit ConstexprString(const char *p, const char *q) : data(nullptr) {
    auto p_size = __builtin_strlen(p);
    auto q_size = __builtin_strlen(q);
    data = new char[p_size + q_size + 1];
    __builtin_memcpy(data, p, p_size);
    __builtin_memcpy(data + p_size, q, q_size + 1);
  }
  constexpr ConstexprString(const ConstexprString &o) : ConstexprString(o.data) {}
  constexpr ConstexprString(ConstexprString &&o) : data(o.data) { o.data = nullptr; }
  constexpr ConstexprString &operator=(const ConstexprString &o) {
    return *this = ConstexprString(o);
  }
  constexpr ConstexprString &operator=(ConstexprString &&o) {
    delete[] data;
    data = o.data;
    o.data = nullptr;
    return *this;
  }
  constexpr ~ConstexprString() { delete[] data; }
  char *data;

  friend constexpr ConstexprString operator+(const ConstexprString &a, const ConstexprString &b) {
    return ConstexprString(a.data, b.data);
  }
  friend constexpr ConstexprString &operator+=(ConstexprString &a, const ConstexprString &b) {
    return a = a + b;
  }
  friend constexpr bool operator==(const ConstexprString &a, const ConstexprString &b) {
    return __builtin_strcmp(a.data, b.data) == 0;
  }
};

template<typename... T> constexpr void Format(ConstexprString &out, const char *fmt, T... args);

struct Arg {
  template<typename T, int (*)[__is_integral(T) ? 1 : -1] = nullptr>
  constexpr Arg(T value) {
    bool negative = false;
    if (value < 0) {
      value = -value;
      negative = true;
    }
    while (value > 0) {
      char str[2] = {char('0' + value % 10), '\0'};
      s = ConstexprString(str) + s;
      value /= 10;
    }
    if (negative)
      s = "-" + s;
  }
  template<typename T, int (*)[__is_class(T) ? 1 : -1] = nullptr>
  constexpr Arg(const T &value) {
    __builtin_dump_struct(&value, Format, s);
  }
  constexpr Arg(const char *s) : s(s) {}
  constexpr Arg(const ConstexprString *s) : s("\"" + *s + "\"") {}
  template<typename T, int (*)[__is_integral(T) ? 1 : -1] = nullptr>
  constexpr Arg(const T *p) : s("reference to " + Arg(*p).s) {}
  ConstexprString s;
};

template<typename... T> constexpr void Format(ConstexprString &out, const char *fmt, T... args) { // #Format
  Arg formatted_args[] = {args...};
  int i = 0;
  while (const char *percent = __builtin_strchr(fmt, '%')) {
    if (percent[1] == '%') continue;
    if (percent != fmt && percent[-1] == '*') --percent;
    out += ConstexprString(fmt, percent - fmt);
    out += formatted_args[i++].s;

    // Skip past format specifier until we hit a conversion specifier.
    fmt = percent;
    while (!__builtin_strchr("diouxXeEfFgGcsp", *fmt)) ++fmt;
    // Skip the conversion specifier too. TODO: Check it's the right one.
    ++fmt;
  }
  out += ConstexprString(fmt);
}

template<typename T> constexpr ConstexprString ToString(const T &t) { return Arg(t).s; }

struct A {
  int x, y, z : 3;
  int : 4;
  ConstexprString s;
};
struct B : A {
  int p, q;
  struct {
    int anon1, anon2;
  };
  union {
    int anon3;
  };
  struct {
    int m;
  } c;
  int &&r;
};

#if PRINT_OUTPUT
#include <stdio.h>
int main() {
  puts(ToString(B{1, 2, 3, "hello", 4, 5, 6, 7, 8, 9, 10}).data);
}
#else
static_assert(ToString(B{1, 2, 3, "hello", 4, 5, 6, 7, 8, 9, 10}) == &R"(
B {
  A {
    int x = 1
    int y = 2
    int z : 3 = 3
    ConstexprString s = "hello"
  }
  int p = 4
  int q = 5
  int anon1 = 6
  int anon2 = 7
  int anon3 = 8
  struct (unnamed) c = {
    int m = 9
  }
  int && r = reference to 10
}
)"[1]);

class Incomplete; // #incomplete-type

template <class T>
class Class {
  T value = {};
};

void errors(B b) {
  ConstexprString cs;
  __builtin_dump_struct(); // expected-error {{too few arguments to function call, expected 2, have 0}}
  __builtin_dump_struct(1); // expected-error {{too few arguments to function call, expected 2, have 1}}
  __builtin_dump_struct(1, 2); // expected-error {{expected pointer to struct as 1st argument to '__builtin_dump_struct', found 'int'}}
  __builtin_dump_struct(&b, 2); // expected-error {{expected a callable expression as 2nd argument to '__builtin_dump_struct', found 'int'}}
  __builtin_dump_struct(&b, Format, 0); // expected-error {{no matching function for call to 'Format'}}
                                        // expected-note@-1 {{in call to printing function with arguments '(0, "%s", "B")' while dumping struct}}
                                        // expected-note@#Format {{no known conversion from 'int' to 'ConstexprString &' for 1st argument}}
  __builtin_dump_struct((Incomplete *)nullptr, Format, cs); // expected-error {{incomplete type 'Incomplete' where a complete type is required}}
                                        // expected-note@#incomplete-type {{forward declaration of 'Incomplete'}}
  // Ensure the Class<int> gets instantiated; otherwise crash happens.
  __builtin_dump_struct((Class<int> *)nullptr, Format, cs);
}
#endif

// Check that PseudoObjectExprBitfields:NumSubExprs doesn't overflow. This
// would previously cause a crash.
struct t1 {
  int v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16,
      v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31,
      v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46,
      v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60, v61,
      v62, v63, v64, v65, v66, v67, v68, v69, v70, v71, v72, v73, v74, v75, v76,
      v77, v78, v79, v80, v81, v82, v83, v84, v85, v86, v87, v88, v89, v90, v91,
      v92, v93, v94, v95, v96, v97, v98, v99;
};

struct t2 {
  t1 v0, v1, v2, v3, v4, v5, v6, v7, v8, v9, v10, v11, v12, v13, v14, v15, v16,
      v17, v18, v19, v20, v21, v22, v23, v24, v25, v26, v27, v28, v29, v30, v31,
      v32, v33, v34, v35, v36, v37, v38, v39, v40, v41, v42, v43, v44, v45, v46,
      v47, v48, v49, v50, v51, v52, v53, v54, v55, v56, v57, v58, v59, v60, v61,
      v62, v63, v64, v65, v66, v67, v68, v69, v70, v71, v72, v73, v74, v75, v76,
      v77, v78, v79, v80, v81, v82, v83, v84, v85, v86, v87, v88, v89, v90, v91,
      v92, v93, v94, v95, v96, v97, v98, v99;
};

int printf(const char *, ...);
void f1(t2 w) { __builtin_dump_struct(&w, printf); }