forked from OSchip/llvm-project
400 lines
12 KiB
C++
400 lines
12 KiB
C++
// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -triple x86_64-apple-macosx10.14.0 %s
|
|
// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -triple x86_64-apple-macosx10.14.0 %s -fno-signed-char
|
|
// RUN: %clang_cc1 -verify -std=c++2a -fsyntax-only -triple aarch64_be-linux-gnu %s
|
|
|
|
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
|
|
# define LITTLE_END 1
|
|
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
|
|
# define LITTLE_END 0
|
|
#else
|
|
# error "huh?"
|
|
#endif
|
|
|
|
template <class T, class V> struct is_same {
|
|
static constexpr bool value = false;
|
|
};
|
|
template <class T> struct is_same<T, T> {
|
|
static constexpr bool value = true;
|
|
};
|
|
|
|
static_assert(sizeof(int) == 4);
|
|
static_assert(sizeof(long long) == 8);
|
|
|
|
template <class To, class From>
|
|
constexpr To bit_cast(const From &from) {
|
|
static_assert(sizeof(To) == sizeof(From));
|
|
#ifdef __CHAR_UNSIGNED__
|
|
// expected-note@+4 2 {{indeterminate value can only initialize an object of type 'unsigned char', 'char', or 'std::byte'; 'signed char' is invalid}}
|
|
#else
|
|
// expected-note@+2 2 {{indeterminate value can only initialize an object of type 'unsigned char' or 'std::byte'; 'signed char' is invalid}}
|
|
#endif
|
|
return __builtin_bit_cast(To, from);
|
|
}
|
|
|
|
template <class Intermediate, class Init>
|
|
constexpr bool round_trip(const Init &init) {
|
|
return bit_cast<Init>(bit_cast<Intermediate>(init)) == init;
|
|
}
|
|
|
|
void test_int() {
|
|
static_assert(round_trip<unsigned>((int)-1));
|
|
static_assert(round_trip<unsigned>((int)0x12345678));
|
|
static_assert(round_trip<unsigned>((int)0x87654321));
|
|
static_assert(round_trip<unsigned>((int)0x0C05FEFE));
|
|
}
|
|
|
|
void test_array() {
|
|
constexpr unsigned char input[] = {0xCA, 0xFE, 0xBA, 0xBE};
|
|
constexpr unsigned expected = LITTLE_END ? 0xBEBAFECA : 0xCAFEBABE;
|
|
static_assert(bit_cast<unsigned>(input) == expected);
|
|
}
|
|
|
|
void test_record() {
|
|
struct int_splicer {
|
|
unsigned x;
|
|
unsigned y;
|
|
|
|
constexpr bool operator==(const int_splicer &other) const {
|
|
return other.x == x && other.y == y;
|
|
}
|
|
};
|
|
|
|
constexpr int_splicer splice{0x0C05FEFE, 0xCAFEBABE};
|
|
|
|
static_assert(bit_cast<unsigned long long>(splice) == (LITTLE_END
|
|
? 0xCAFEBABE0C05FEFE
|
|
: 0x0C05FEFECAFEBABE));
|
|
|
|
static_assert(bit_cast<int_splicer>(0xCAFEBABE0C05FEFE).x == (LITTLE_END
|
|
? 0x0C05FEFE
|
|
: 0xCAFEBABE));
|
|
|
|
static_assert(round_trip<unsigned long long>(splice));
|
|
static_assert(round_trip<long long>(splice));
|
|
|
|
struct base2 {
|
|
};
|
|
|
|
struct base3 {
|
|
unsigned z;
|
|
};
|
|
|
|
struct bases : int_splicer, base2, base3 {
|
|
unsigned doublez;
|
|
};
|
|
|
|
struct tuple4 {
|
|
unsigned x, y, z, doublez;
|
|
|
|
constexpr bool operator==(tuple4 const &other) const {
|
|
return x == other.x && y == other.y &&
|
|
z == other.z && doublez == other.doublez;
|
|
}
|
|
};
|
|
constexpr bases b = {{1, 2}, {}, {3}, 4};
|
|
constexpr tuple4 t4 = bit_cast<tuple4>(b);
|
|
static_assert(t4 == tuple4{1, 2, 3, 4});
|
|
static_assert(round_trip<tuple4>(b));
|
|
}
|
|
|
|
void test_partially_initialized() {
|
|
struct pad {
|
|
signed char x;
|
|
int y;
|
|
};
|
|
|
|
struct no_pad {
|
|
signed char x;
|
|
signed char p1, p2, p3;
|
|
int y;
|
|
};
|
|
|
|
static_assert(sizeof(pad) == sizeof(no_pad));
|
|
|
|
constexpr pad pir{4, 4};
|
|
// expected-error@+2 {{constexpr variable 'piw' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{in call to 'bit_cast(pir)'}}
|
|
constexpr int piw = bit_cast<no_pad>(pir).x;
|
|
|
|
// expected-error@+2 {{constexpr variable 'bad' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{in call to 'bit_cast(pir)'}}
|
|
constexpr no_pad bad = bit_cast<no_pad>(pir);
|
|
|
|
constexpr pad fine = bit_cast<pad>(no_pad{1, 2, 3, 4, 5});
|
|
static_assert(fine.x == 1 && fine.y == 5);
|
|
}
|
|
|
|
void no_bitfields() {
|
|
// FIXME!
|
|
struct S {
|
|
unsigned char x : 8;
|
|
};
|
|
|
|
struct G {
|
|
unsigned char x : 8;
|
|
};
|
|
|
|
constexpr S s{0};
|
|
// expected-error@+2 {{constexpr variable 'g' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{constexpr bit_cast involving bit-field is not yet supported}}
|
|
constexpr G g = __builtin_bit_cast(G, s);
|
|
}
|
|
|
|
void array_members() {
|
|
struct S {
|
|
int ar[3];
|
|
|
|
constexpr bool operator==(const S &rhs) {
|
|
return ar[0] == rhs.ar[0] && ar[1] == rhs.ar[1] && ar[2] == rhs.ar[2];
|
|
}
|
|
};
|
|
|
|
struct G {
|
|
int a, b, c;
|
|
|
|
constexpr bool operator==(const G &rhs) {
|
|
return a == rhs.a && b == rhs.b && c == rhs.c;
|
|
}
|
|
};
|
|
|
|
constexpr S s{{1, 2, 3}};
|
|
constexpr G g = bit_cast<G>(s);
|
|
static_assert(g.a == 1 && g.b == 2 && g.c == 3);
|
|
|
|
static_assert(round_trip<G>(s));
|
|
static_assert(round_trip<S>(g));
|
|
}
|
|
|
|
void bad_types() {
|
|
union X {
|
|
int x;
|
|
};
|
|
|
|
struct G {
|
|
int g;
|
|
};
|
|
// expected-error@+2 {{constexpr variable 'g' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{bit_cast from a union type is not allowed in a constant expression}}
|
|
constexpr G g = __builtin_bit_cast(G, X{0});
|
|
// expected-error@+2 {{constexpr variable 'x' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{bit_cast to a union type is not allowed in a constant expression}}
|
|
constexpr X x = __builtin_bit_cast(X, G{0});
|
|
|
|
struct has_pointer {
|
|
// expected-note@+1 2 {{invalid type 'int *' is a member of 'has_pointer'}}
|
|
int *ptr;
|
|
};
|
|
|
|
// expected-error@+2 {{constexpr variable 'ptr' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{bit_cast from a pointer type is not allowed in a constant expression}}
|
|
constexpr unsigned long ptr = __builtin_bit_cast(unsigned long, has_pointer{0});
|
|
// expected-error@+2 {{constexpr variable 'hptr' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{bit_cast to a pointer type is not allowed in a constant expression}}
|
|
constexpr has_pointer hptr = __builtin_bit_cast(has_pointer, 0ul);
|
|
}
|
|
|
|
void backtrace() {
|
|
struct A {
|
|
// expected-note@+1 {{invalid type 'int *' is a member of 'A'}}
|
|
int *ptr;
|
|
};
|
|
|
|
struct B {
|
|
// expected-note@+1 {{invalid type 'A [10]' is a member of 'B'}}
|
|
A as[10];
|
|
};
|
|
|
|
// expected-note@+1 {{invalid type 'B' is a base of 'C'}}
|
|
struct C : B {
|
|
};
|
|
|
|
struct E {
|
|
unsigned long ar[10];
|
|
};
|
|
|
|
// expected-error@+2 {{constexpr variable 'e' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{bit_cast from a pointer type is not allowed in a constant expression}}
|
|
constexpr E e = __builtin_bit_cast(E, C{});
|
|
}
|
|
|
|
void test_array_fill() {
|
|
constexpr unsigned char a[4] = {1, 2};
|
|
constexpr unsigned int i = bit_cast<unsigned int>(a);
|
|
static_assert(i == (LITTLE_END ? 0x00000201 : 0x01020000));
|
|
}
|
|
|
|
typedef decltype(nullptr) nullptr_t;
|
|
|
|
#ifdef __CHAR_UNSIGNED__
|
|
// expected-note@+5 {{indeterminate value can only initialize an object of type 'unsigned char', 'char', or 'std::byte'; 'unsigned long' is invalid}}
|
|
#else
|
|
// expected-note@+3 {{indeterminate value can only initialize an object of type 'unsigned char' or 'std::byte'; 'unsigned long' is invalid}}
|
|
#endif
|
|
// expected-error@+1 {{constexpr variable 'test_from_nullptr' must be initialized by a constant expression}}
|
|
constexpr unsigned long test_from_nullptr = __builtin_bit_cast(unsigned long, nullptr);
|
|
|
|
constexpr int test_from_nullptr_pass = (__builtin_bit_cast(unsigned char[8], nullptr), 0);
|
|
|
|
constexpr int test_to_nullptr() {
|
|
nullptr_t npt = __builtin_bit_cast(nullptr_t, 0ul);
|
|
|
|
struct indet_mem {
|
|
unsigned char data[sizeof(void *)];
|
|
};
|
|
indet_mem im = __builtin_bit_cast(indet_mem, nullptr);
|
|
nullptr_t npt2 = __builtin_bit_cast(nullptr_t, im);
|
|
|
|
return 0;
|
|
}
|
|
|
|
constexpr int ttn = test_to_nullptr();
|
|
|
|
// expected-warning@+2 {{returning reference to local temporary object}}
|
|
// expected-note@+1 {{temporary created here}}
|
|
constexpr const long &returns_local() { return 0L; }
|
|
|
|
// expected-error@+2 {{constexpr variable 'test_nullptr_bad' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{read of temporary whose lifetime has ended}}
|
|
constexpr nullptr_t test_nullptr_bad = __builtin_bit_cast(nullptr_t, returns_local());
|
|
|
|
constexpr int test_indeterminate(bool read_indet) {
|
|
struct pad {
|
|
char a;
|
|
int b;
|
|
};
|
|
|
|
struct no_pad {
|
|
char a;
|
|
unsigned char p1, p2, p3;
|
|
int b;
|
|
};
|
|
|
|
pad p{1, 2};
|
|
no_pad np = bit_cast<no_pad>(p);
|
|
|
|
int tmp = np.a + np.b;
|
|
|
|
unsigned char& indet_ref = np.p1;
|
|
|
|
if (read_indet) {
|
|
// expected-note@+1 {{read of uninitialized object is not allowed in a constant expression}}
|
|
tmp = indet_ref;
|
|
}
|
|
|
|
indet_ref = 0;
|
|
|
|
return 0;
|
|
}
|
|
|
|
constexpr int run_test_indeterminate = test_indeterminate(false);
|
|
// expected-error@+2 {{constexpr variable 'run_test_indeterminate2' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{in call to 'test_indeterminate(true)'}}
|
|
constexpr int run_test_indeterminate2 = test_indeterminate(true);
|
|
|
|
struct ref_mem {
|
|
const int &rm;
|
|
};
|
|
|
|
constexpr int global_int = 0;
|
|
|
|
// expected-error@+2 {{constexpr variable 'run_ref_mem' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{bit_cast from a type with a reference member is not allowed in a constant expression}}
|
|
constexpr unsigned long run_ref_mem = __builtin_bit_cast(
|
|
unsigned long, ref_mem{global_int});
|
|
|
|
union u {
|
|
int im;
|
|
};
|
|
|
|
// expected-error@+2 {{constexpr variable 'run_u' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{bit_cast from a union type is not allowed in a constant expression}}
|
|
constexpr int run_u = __builtin_bit_cast(int, u{32});
|
|
|
|
struct vol_mem {
|
|
volatile int x;
|
|
};
|
|
|
|
// expected-error@+2 {{constexpr variable 'run_vol_mem' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{non-literal type 'vol_mem' cannot be used in a constant expression}}
|
|
constexpr int run_vol_mem = __builtin_bit_cast(int, vol_mem{43});
|
|
|
|
struct mem_ptr {
|
|
int vol_mem::*x; // expected-note{{invalid type 'int vol_mem::*' is a member of 'mem_ptr'}}
|
|
};
|
|
// expected-error@+2 {{constexpr variable 'run_mem_ptr' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{bit_cast from a member pointer type is not allowed in a constant expression}}
|
|
constexpr int run_mem_ptr = __builtin_bit_cast(unsigned long, mem_ptr{nullptr});
|
|
|
|
struct A { char c; /* char padding : 8; */ short s; };
|
|
struct B { unsigned char x[4]; };
|
|
|
|
constexpr B one() {
|
|
A a = {1, 2};
|
|
return bit_cast<B>(a);
|
|
}
|
|
constexpr char good_one = one().x[0] + one().x[2] + one().x[3];
|
|
// expected-error@+2 {{constexpr variable 'bad_one' must be initialized by a constant expression}}
|
|
// expected-note@+1 {{read of uninitialized object is not allowed in a constant expression}}
|
|
constexpr char bad_one = one().x[1];
|
|
|
|
constexpr A two() {
|
|
B b = one(); // b.x[1] is indeterminate.
|
|
b.x[0] = 'a';
|
|
b.x[2] = 1;
|
|
b.x[3] = 2;
|
|
return bit_cast<A>(b);
|
|
}
|
|
constexpr short good_two = two().c + two().s;
|
|
|
|
namespace std {
|
|
enum byte : unsigned char {};
|
|
}
|
|
|
|
enum my_byte : unsigned char {};
|
|
|
|
struct pad {
|
|
char a;
|
|
int b;
|
|
};
|
|
|
|
constexpr int ok_byte = (__builtin_bit_cast(std::byte[8], pad{1, 2}), 0);
|
|
constexpr int ok_uchar = (__builtin_bit_cast(unsigned char[8], pad{1, 2}), 0);
|
|
|
|
#ifdef __CHAR_UNSIGNED__
|
|
// expected-note@+5 {{indeterminate value can only initialize an object of type 'unsigned char', 'char', or 'std::byte'; 'my_byte' is invalid}}}}
|
|
#else
|
|
// expected-note@+3 {{indeterminate value can only initialize an object of type 'unsigned char' or 'std::byte'; 'my_byte' is invalid}}
|
|
#endif
|
|
// expected-error@+1 {{constexpr variable 'bad_my_byte' must be initialized by a constant expression}}
|
|
constexpr int bad_my_byte = (__builtin_bit_cast(my_byte[8], pad{1, 2}), 0);
|
|
#ifndef __CHAR_UNSIGNED__
|
|
// expected-error@+3 {{constexpr variable 'bad_char' must be initialized by a constant expression}}
|
|
// expected-note@+2 {{indeterminate value can only initialize an object of type 'unsigned char' or 'std::byte'; 'char' is invalid}}
|
|
#endif
|
|
constexpr int bad_char = (__builtin_bit_cast(char[8], pad{1, 2}), 0);
|
|
|
|
struct pad_buffer { unsigned char data[sizeof(pad)]; };
|
|
constexpr bool test_pad_buffer() {
|
|
pad x = {1, 2};
|
|
pad_buffer y = __builtin_bit_cast(pad_buffer, x);
|
|
pad z = __builtin_bit_cast(pad, y);
|
|
return x.a == z.a && x.b == z.b;
|
|
}
|
|
static_assert(test_pad_buffer());
|
|
|
|
constexpr unsigned char identity1a = 42;
|
|
constexpr unsigned char identity1b = __builtin_bit_cast(unsigned char, identity1a);
|
|
static_assert(identity1b == 42);
|
|
|
|
struct IdentityInStruct {
|
|
unsigned char n;
|
|
};
|
|
constexpr IdentityInStruct identity2a = {42};
|
|
constexpr unsigned char identity2b = __builtin_bit_cast(unsigned char, identity2a.n);
|
|
|
|
union IdentityInUnion {
|
|
unsigned char n;
|
|
};
|
|
constexpr IdentityInUnion identity3a = {42};
|
|
constexpr unsigned char identity3b = __builtin_bit_cast(unsigned char, identity3a.n);
|