// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wimplicit-fallthrough -Wunreachable-code-fallthrough %s
int fallthrough(int n) {
switch (n / 10) {
if (n - 1) {
n = 100;
} else if (n - 2) {
n = 101;
} else if (n - 3) {
n = 102;
}
case -1: // no warning here, ignore fall-through from unreachable code
;
case 0: {// expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
}
case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
n += 100 ;
case 3: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
if (n > 0)
n += 200;
case 4: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
if (n < 0)
;
case 5: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
switch (n) {
case 111:
break;
case 112:
break;
case 113:
break ;
}
case 6: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
n += 300;
case 66: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'break;' to avoid fall-through}}
case 67:
case 68:
break;
}
switch (n / 15) {
label_default:
default:
n += 333;
if (n % 10)
goto label_default;
break;
case 70:
n += 335;
break;
}
switch (n / 20) {
[[likely]] case 6:
[[clang::fallthrough]];
case 7:
n += 400;
[[clang::fallthrough]];
case 9: // no warning here, intended fall-through marked with an attribute
n += 800;
[[clang::fallthrough]];
default: { // no warning here, intended fall-through marked with an attribute
if (n % 2 == 0) {
return 1;
} else {
[[clang::fallthrough]];
}
}
case 10: // no warning here, intended fall-through marked with an attribute
if (n % 3 == 0) {
n %= 3;
} else {
[[clang::fallthrough]];
}
case 110: // expected-warning{{unannotated fall-through between switch labels}} but no fix-it hint as we have one fall-through annotation!
n += 800;
}
switch (n / 30) {
case 6:
[[unlikely, clang::fallthrough]];
case 11:
case 12: // no warning here, intended fall-through, no statement between labels
n += 1600;
}
switch (n / 40) {
case 13:
if (n % 2 == 0) {
return 1;
} else {
return 2;
}
case 15: // no warning here, there's no fall-through
n += 3200;
}
switch (n / 50) {
case 17: {
if (n % 2 == 0) {
return 1;
} else {
return 2;
}
}
case 19: { // no warning here, there's no fall-through
n += 6400;
return 3;
}
case 21: { // no warning here, there's no fall-through
break;
}
case 23: // no warning here, there's no fall-through
n += 128000;
break;
case 25: // no warning here, there's no fall-through
break;
}
return n;
}
class ClassWithDtor {
public:
~ClassWithDtor() {}
};
void fallthrough2(int n) {
switch (n) {
case 0:
{
ClassWithDtor temp;
break;
}
default: // no warning here, there's no fall-through
break;
}
}
void fallthrough3(int n) {
switch (n) {
case 1:
do {
return;
} while (0);
case 2:
do {
ClassWithDtor temp;
return;
} while (0);
case 3:
break;
}
}
#define MY_SWITCH(X, Y, Z, U, V) switch (X) { case Y: Z; case U: V; }
#define MY_SWITCH2(X, Y, Z) switch (X) { Y; Z; }
#define MY_CASE(X, Y) case X: Y
#define MY_CASE2(X, Y, U, V) case X: Y; case U: V
int fallthrough_macro1(int n) {
MY_SWITCH(n, 13, n *= 2, 14, break) // expected-warning{{unannotated fall-through between switch labels}}
switch (n + 1) {
MY_CASE(33, n += 2);
MY_CASE(44, break); // expected-warning{{unannotated fall-through between switch labels}}
MY_CASE(55, n += 3);
}
switch (n + 3) {
MY_CASE(333, return 333);
MY_CASE2(444, n += 44, 4444, break); // expected-warning{{unannotated fall-through between switch labels}}
MY_CASE(555, n += 33);
}
MY_SWITCH2(n + 4, MY_CASE(17, n *= 3), MY_CASE(19, break)) // expected-warning{{unannotated fall-through between switch labels}}
MY_SWITCH2(n + 5, MY_CASE(21, break), MY_CASE2(23, n *= 7, 25, break)) // expected-warning{{unannotated fall-through between switch labels}}
return n;
}
void fallthrough_cfgblock_with_null_successor(int x) {
(x && "") ? (void)(0) : (void)(1);
switch (x) {}
}
int fallthrough_position(int n) {
switch (n) {
n += 300;
[[clang::fallthrough]]; // expected-warning{{fallthrough annotation in unreachable code}}
case 221:
return 1;
[[clang::fallthrough]]; // expected-warning{{fallthrough annotation in unreachable code}}
case 222:
return 2;
__attribute__((fallthrough)); // expected-warning{{fallthrough annotation in unreachable code}}
case 223:
n += 400;
case 224: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
;
}
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunreachable-code-fallthrough"
switch (n) {
n += 300;
[[clang::fallthrough]]; // no warning here
case 221:
return 1;
[[clang::fallthrough]]; // no warning here
case 222:
return 2;
__attribute__((fallthrough)); // no warning here
case 223:
if (1)
return 3;
__attribute__((fallthrough)); // no warning here
case 224:
n += 400;
}
#pragma clang diagnostic pop
long p = static_cast<long>(n) * n;
switch (sizeof(p)) {
case 9:
n += static_cast<int>(p >> 32);
[[clang::fallthrough]]; // no warning here
case 5:
n += static_cast<int>(p);
[[clang::fallthrough]]; // no warning here
default:
n += 1;
break;
}
return n;
}
enum Enum {
Value1, Value2
};
int fallthrough_covered_enums(Enum e) {
int n = 0;
switch (e) {
default:
n += 17;
[[clang::fallthrough]]; // no warning here, this shouldn't be treated as unreachable code
case Value1:
n += 19;
break;
case Value2:
n += 21;
break;
}
return n;
}
// Fallthrough annotations in local classes used to generate "fallthrough
// annotation does not directly precede switch label" warning.
void fallthrough_in_local_class() {
class C {
void f(int x) {
switch (x) {
case 0:
x++;
[[clang::fallthrough]]; // no diagnostics
case 1:
x++;
default: // \
expected-warning{{unannotated fall-through between switch labels}} \
expected-note{{insert 'break;' to avoid fall-through}}
break;
}
}
};
}
// Fallthrough annotations in lambdas used to generate "fallthrough
// annotation does not directly precede switch label" warning.
void fallthrough_in_lambda() {
(void)[] {
int x = 0;
switch (x) {
case 0:
x++;
[[clang::fallthrough]]; // no diagnostics
case 1:
x++;
default: // \
expected-warning{{unannotated fall-through between switch labels}} \
expected-note{{insert 'break;' to avoid fall-through}}
break;
}
};
}
namespace PR18983 {
void fatal() __attribute__((noreturn));
int num();
void test() {
switch (num()) {
case 1:
fatal();
// Don't issue a warning.
case 2:
break;
}
}
}
int fallthrough_placement_error(int n) {
switch (n) {
[[clang::fallthrough]]; // expected-warning{{fallthrough annotation in unreachable code}}
n += 300;
case 221:
[[clang::fallthrough]]; // expected-error{{fallthrough annotation does not directly precede switch label}}
return 1;
case 222:
[[clang::fallthrough]]; // expected-error{{fallthrough annotation does not directly precede switch label}}
n += 400;
[[clang::fallthrough]];
case 223:
[[clang::fallthrough]]; // expected-error{{fallthrough annotation does not directly precede switch label}}
}
return n;
}
int fallthrough_targets(int n) {
[[clang::fallthrough]]; // expected-error{{fallthrough annotation is outside switch statement}}
[[clang::fallthrough]] // expected-error{{'fallthrough' attribute only applies to empty statements}}
switch (n) {
case 121:
n += 400;
[[clang::fallthrough]]; // no warning here, correct target
case 123:
[[clang::fallthrough]] // expected-error{{'fallthrough' attribute only applies to empty statements}}
n += 800;
break;
[[clang::fallthrough]] // expected-error{{'fallthrough' attribute is only allowed on empty statements}} expected-note{{did you forget ';'?}}
case 125:
n += 1600;
}
return n;
}
int fallthrough_alt_spelling(int n) {
switch (n) {
case 0:
n++;
[[clang::fallthrough]];
case 1:
n++;
[[clang::__fallthrough__]];
case 2:
n++;
break;
}
return n;
}
int fallthrough_attribute_spelling(int n) {
switch (n) {
case 0:
n++;
__attribute__((fallthrough));
case 1:
n++;
break;
}
return n;
}
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