dead-stores.cpp revision a676d501a001657892c483bd4d651650e168f337
1// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -analyze -analyzer-checker=DeadStores -verify -Wno-unreachable-code %s 2// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -analyze -analyzer-check-objc-mem -analyzer-store=basic -analyzer-constraints=basic -analyzer-checker=DeadStores -verify -Wno-unreachable-code %s 3// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -analyze -analyzer-check-objc-mem -analyzer-store=basic -analyzer-constraints=range -analyzer-checker=DeadStores -verify -Wno-unreachable-code %s 4// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -analyze -analyzer-check-objc-mem -analyzer-store=region -analyzer-constraints=basic -analyzer-checker=DeadStores -verify -Wno-unreachable-code %s 5// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -analyze -analyzer-check-objc-mem -analyzer-store=region -analyzer-constraints=range -analyzer-checker=DeadStores -verify -Wno-unreachable-code %s 6 7//===----------------------------------------------------------------------===// 8// Basic dead store checking (but in C++ mode). 9//===----------------------------------------------------------------------===// 10 11int j; 12void test1() { 13 int x = 4; 14 15 x = x + 1; // expected-warning{{never read}} 16 17 switch (j) { 18 case 1: 19 throw 1; 20 (void)x; 21 break; 22 } 23} 24 25//===----------------------------------------------------------------------===// 26// Dead store checking involving constructors. 27//===----------------------------------------------------------------------===// 28 29class Test2 { 30 int &x; 31public: 32 Test2(int &y) : x(y) {} 33 ~Test2() { ++x; } 34}; 35 36int test2(int x) { 37 { Test2 a(x); } // no-warning 38 return x; 39} 40 41//===----------------------------------------------------------------------===// 42// Dead store checking involving CXXTemporaryExprs 43//===----------------------------------------------------------------------===// 44 45namespace TestTemp { 46 template<typename _Tp> 47 class pencil { 48 public: 49 ~pencil() throw() {} 50 }; 51 template<typename _Tp, typename _Number2> struct _Row_base { 52 _Row_base(const pencil<_Tp>& x) {} 53 }; 54 template<typename _Tp, typename _Number2 = TestTemp::pencil<_Tp> > 55 class row : protected _Row_base<_Tp, _Number2> { 56 typedef _Row_base<_Tp, _Number2> _Base; 57 typedef _Number2 pencil_type; 58 public: 59 explicit row(const pencil_type& __a = pencil_type()) : _Base(__a) {} 60 }; 61} 62 63void test2_b() { 64 TestTemp::row<const char*> x; // no-warning 65} 66 67//===----------------------------------------------------------------------===// 68// Test references. 69//===----------------------------------------------------------------------===// 70 71void test3_a(int x) { 72 x = x + 1; // expected-warning{{never read}} 73} 74 75void test3_b(int &x) { 76 x = x + 1; // no-warninge 77} 78 79void test3_c(int x) { 80 int &y = x; 81 // Shows the limitation of dead stores tracking. The write is really 82 // dead since the value cannot escape the function. 83 ++y; // no-warning 84} 85 86void test3_d(int &x) { 87 int &y = x; 88 ++y; // no-warning 89} 90 91void test3_e(int &x) { 92 int &y = x; 93} 94 95//===----------------------------------------------------------------------===// 96// Dead stores involving 'new' 97//===----------------------------------------------------------------------===// 98 99static void test_new(unsigned n) { 100 char **p = new char* [n]; // expected-warning{{never read}} 101} 102 103//===----------------------------------------------------------------------===// 104// Dead stores in namespaces. 105//===----------------------------------------------------------------------===// 106 107namespace foo { 108 int test_4(int x) { 109 x = 2; // expected-warning{{Value stored to 'x' is never read}} 110 x = 2; 111 return x; 112 } 113} 114 115