150
+ − 1 // RUN: %clang_cc1 -fsyntax-only -verify %s -Wno-unreachable-code
+ − 2
+ − 3 int foo(int X, int Y);
+ − 4
+ − 5 double sqrt(double X); // implicitly const because of no -fmath-errno!
+ − 6
+ − 7 void bar(volatile int *VP, int *P, int A,
+ − 8 _Complex double C, volatile _Complex double VC) {
+ − 9
+ − 10 VP < P; // expected-warning {{relational comparison result unused}}
+ − 11 (void)A;
+ − 12 (void)foo(1,2); // no warning.
+ − 13
+ − 14 A < foo(1, 2); // expected-warning {{relational comparison result unused}}
+ − 15
+ − 16 foo(1,2)+foo(4,3); // expected-warning {{expression result unused}}
+ − 17
+ − 18
+ − 19 *P; // expected-warning {{expression result unused}}
+ − 20 *VP; // no warning.
+ − 21 P[4]; // expected-warning {{expression result unused}}
+ − 22 VP[4]; // no warning.
+ − 23
+ − 24 __real__ C; // expected-warning {{expression result unused}}
+ − 25 __real__ VC;
+ − 26
+ − 27 // We know this can't change errno because of no -fmath-errno.
+ − 28 sqrt(A); // expected-warning {{ignoring return value of function declared with const attribute}}
+ − 29 }
+ − 30
+ − 31 extern void t1();
+ − 32 extern void t2();
+ − 33 void t3(int c) {
+ − 34 c ? t1() : t2();
+ − 35 }
+ − 36
+ − 37 // This shouldn't warn: the expr at the end of the stmtexpr really is used.
+ − 38 int stmt_expr(int x, int y) {
+ − 39 return ({int _a = x, _b = y; _a > _b ? _a : _b; });
+ − 40 }
+ − 41
+ − 42 void nowarn(unsigned char* a, unsigned char* b)
+ − 43 {
+ − 44 unsigned char c = 1;
+ − 45 *a |= c, *b += c;
+ − 46
+ − 47
+ − 48 // PR4633
+ − 49 int y, x;
+ − 50 ((void)0), y = x;
+ − 51 }
+ − 52
+ − 53 void t4(int a) {
+ − 54 int b = 0;
+ − 55
+ − 56 if (a)
+ − 57 b < 1; // expected-warning{{relational comparison result unused}}
+ − 58 else
+ − 59 b < 2; // expected-warning{{relational comparison result unused}}
+ − 60
+ − 61 while (1)
+ − 62 b < 3; // expected-warning{{relational comparison result unused}}
+ − 63
+ − 64 do
+ − 65 b < 4; // expected-warning{{relational comparison result unused}}
+ − 66 while (1);
+ − 67
+ − 68 for (;;)
+ − 69 b < 5; // expected-warning{{relational comparison result unused}}
+ − 70
+ − 71 for (b < 1;;) {} // expected-warning{{relational comparison result unused}}
+ − 72 for (;b < 1;) {}
+ − 73 for (;;b < 1) {} // expected-warning{{relational comparison result unused}}
+ − 74 }
+ − 75
+ − 76 // rdar://7186119
+ − 77 int t5f(void) __attribute__((warn_unused_result));
+ − 78 void t5() {
+ − 79 t5f(); // expected-warning {{ignoring return value of function declared with 'warn_unused_result' attribute}}
+ − 80 }
+ − 81
+ − 82
+ − 83 int fn1() __attribute__ ((warn_unused_result));
+ − 84 int fn2() __attribute__ ((pure));
+ − 85 int fn3() __attribute__ ((__const));
+ − 86 // rdar://6587766
+ − 87 int t6() {
+ − 88 if (fn1() < 0 || fn2(2,1) < 0 || fn3(2) < 0) // no warnings
+ − 89 return -1;
+ − 90
+ − 91 fn1(); // expected-warning {{ignoring return value of function declared with 'warn_unused_result' attribute}}
+ − 92 fn2(92, 21); // expected-warning {{ignoring return value of function declared with pure attribute}}
+ − 93 fn3(42); // expected-warning {{ignoring return value of function declared with const attribute}}
+ − 94 __builtin_abs(0); // expected-warning {{ignoring return value of function declared with const attribute}}
+ − 95 (void)0, fn1(); // expected-warning {{ignoring return value of function declared with 'warn_unused_result' attribute}}
+ − 96 return 0;
+ − 97 }
+ − 98
+ − 99 int t7 __attribute__ ((warn_unused_result)); // expected-warning {{'warn_unused_result' attribute only applies to Objective-C methods, enums, structs, unions, classes, functions, and function pointers}}
+ − 100
+ − 101 // PR4010
+ − 102 int (*fn4)(void) __attribute__ ((warn_unused_result));
+ − 103 void t8() {
+ − 104 fn4(); // expected-warning {{ignoring return value of function declared with 'warn_unused_result' attribute}}
+ − 105 }
+ − 106
+ − 107 void t9() __attribute__((warn_unused_result)); // expected-warning {{attribute 'warn_unused_result' cannot be applied to functions without return value}}
+ − 108
+ − 109 // rdar://7410924
+ − 110 void *some_function(void);
+ − 111 void t10() {
+ − 112 (void*) some_function(); //expected-warning {{expression result unused; should this cast be to 'void'?}}
+ − 113 }
+ − 114
+ − 115 void f(int i, ...) {
+ − 116 __builtin_va_list ap;
+ − 117
+ − 118 __builtin_va_start(ap, i);
+ − 119 __builtin_va_arg(ap, int);
+ − 120 __builtin_va_end(ap);
+ − 121 }
+ − 122
+ − 123 // PR8371
+ − 124 int fn5() __attribute__ ((__const));
+ − 125
+ − 126 // Don't warn for unused expressions in macro bodies; however, do warn for
+ − 127 // unused expressions in macro arguments. Macros below are reduced from code
+ − 128 // found in the wild.
+ − 129 #define NOP(a) (a)
+ − 130 #define M1(a, b) (long)foo((a), (b))
+ − 131 #define M2 (long)0;
+ − 132 #define M3(a) (t3(a), fn2())
+ − 133 #define M4(a, b) (foo((a), (b)) ? 0 : t3(a), 1)
+ − 134 #define M5(a, b) (foo((a), (b)), 1)
+ − 135 #define M6() fn1()
+ − 136 #define M7() fn2()
+ − 137 void t11(int i, int j) {
+ − 138 M1(i, j); // no warning
+ − 139 NOP((long)foo(i, j)); // expected-warning {{expression result unused}}
+ − 140 M2; // no warning
+ − 141 NOP((long)0); // expected-warning {{expression result unused}}
+ − 142 M3(i); // no warning
+ − 143 NOP((t3(i), fn2())); // expected-warning {{ignoring return value}}
+ − 144 M4(i, j); // no warning
+ − 145 NOP((foo(i, j) ? 0 : t3(i), 1)); // expected-warning {{expression result unused}}
+ − 146 M5(i, j); // no warning
+ − 147 NOP((foo(i, j), 1)); // expected-warning {{expression result unused}}
+ − 148 M6(); // expected-warning {{ignoring return value}}
+ − 149 M7(); // no warning
+ − 150 }
+ − 151 #undef NOP
+ − 152 #undef M1
+ − 153 #undef M2
+ − 154 #undef M3
+ − 155 #undef M4
+ − 156 #undef M5
+ − 157 #undef M6
+ − 158 #undef M7
+ − 159
+ − 160 #define UNREFERENCED_PARAMETER(x) (x)
+ − 161
+ − 162 void unused_parm(int a) {
+ − 163 // Don't warn if the warning is introduced by a macro that's spelled
+ − 164 // UNREFERENCED_PARAMETER, as that's a commonly used macro in Windows headers.
+ − 165 UNREFERENCED_PARAMETER(a);
+ − 166 }