clang/test/CodeGenCXX/devirtualize-virtual-function-calls.cpp

   1 // RUN: %clang_cc1 -std=c++98 %s -triple armv7-none-eabi -emit-llvm -o - | FileCheck %s
   2 // RUN: %clang_cc1 -std=c++11 %s -triple armv7-none-eabi -emit-llvm -o - | FileCheck %s
   3 // RUN: %clang_cc1 -std=c++1z %s -triple armv7-none-eabi -emit-llvm -o - | FileCheck %s
   4
   5 struct A {
   6   virtual void f();
   7   virtual void f_const() const;
   8   virtual void g();
   9
  10   A h();
  11 };
  12
  13 A g();
  14
  15 void f(A a, A *ap, A& ar) {
  16   // This should not be a virtual function call.
  17
  18   // CHECK: call void @_ZN1A1fEv(ptr {{[^,]*}} %a)
  19   a.f();
  20
  21   // CHECK: call void %
  22   ap->f();
  23
  24   // CHECK: call void %
  25   ar.f();
  26
  27   // CHECK: call void @_ZN1A1fEv
  28   A().f();
  29
  30   // CHECK: call void @_ZN1A1fEv
  31   g().f();
  32
  33   // CHECK: call void @_ZN1A1fEv
  34   a.h().f();
  35
  36   // CHECK: call void @_ZNK1A7f_constEv
  37   a.f_const();
  38
  39   // CHECK: call void @_ZN1A1fEv
  40   (a).f();
  41 }
  42
  43 struct D : A { virtual void g(); };
  44 struct XD { D d; };
  45
  46 D gd();
  47
  48 void fd(D d, XD xd, D *p) {
  49   // CHECK: call void @_ZN1A1fEv(ptr
  50   d.f();
  51
  52   // CHECK: call void @_ZN1D1gEv(ptr
  53   d.g();
  54
  55   // CHECK: call void @_ZN1A1fEv
  56   D().f();
  57
  58   // CHECK: call void @_ZN1D1gEv
  59   D().g();
  60
  61   // CHECK: call void @_ZN1A1fEv
  62   gd().f();
  63
  64   // CHECK: call void @_ZNK1A7f_constEv
  65   d.f_const();
  66
  67   // CHECK: call void @_ZN1A1fEv
  68   (d).f();
  69
  70   // CHECK: call void @_ZN1A1fEv
  71   (true, d).f();
  72
  73   // CHECK: call void @_ZN1D1gEv
  74   (true, d).g();
  75
  76   // CHECK: call void @_ZN1A1fEv
  77   xd.d.f();
  78
  79   // CHECK: call void @_ZN1A1fEv
  80   XD().d.f();
  81
  82   // CHECK: call void @_ZN1A1fEv
  83   D XD::*mp;
  84   (xd.*mp).f();
  85
  86   // CHECK: call void @_ZN1D1gEv
  87   (xd.*mp).g();
  88
  89   // Can't devirtualize this; we have no guarantee that p points to a D here,
  90   // due to the "single object is considered to be an array of one element"
  91   // rule.
  92   // CHECK: call void %
  93   p[0].f();
  94
  95   // FIXME: We can devirtualize this, by C++1z [expr.add]/6 (if the array
  96   // element type and the pointee type are not similar, behavior is undefined).
  97   // CHECK: call void %
  98   p[1].f();
  99 }
 100
 101 struct B {
 102   virtual void f();
 103   ~B();
 104
 105   B h();
 106 };
 107
 108
 109 void f() {
 110   // CHECK: call void @_ZN1B1fEv
 111   B().f();
 112
 113   // CHECK: call void @_ZN1B1fEv
 114   B().h().f();
 115 }
 116
 117 namespace test2 {
 118   struct foo {
 119     virtual void f();
 120     virtual ~foo();
 121   };
 122
 123   struct bar : public foo {
 124     virtual void f();
 125     virtual ~bar();
 126   };
 127
 128   void f(bar *b) {
 129     // CHECK: call void @_ZN5test23foo1fEv
 130     // CHECK: call noundef ptr @_ZN5test23fooD1Ev
 131     b->foo::f();
 132     b->foo::~foo();
 133   }
 134 }
 135
 136 namespace test3 {
 137   // Test that we don't crash in this case.
 138   struct B {
 139   };
 140   struct D : public B {
 141   };
 142   void f(D d) {
 143     // CHECK-LABEL: define{{.*}} void @_ZN5test31fENS_1DE
 144     d.B::~B();
 145   }
 146 }
 147
 148 namespace test4 {
 149   struct Animal {
 150     virtual void eat();
 151   };
 152   struct Fish : Animal {
 153     virtual void eat();
 154   };
 155   struct Wrapper {
 156     Fish fish;
 157   };
 158   extern Wrapper *p;
 159   void test() {
 160     // CHECK: call void @_ZN5test44Fish3eatEv
 161     p->fish.eat();
 162   }
 163 }
 164
 165 // Do not devirtualize to pure virtual function calls.
 166 namespace test5 {
 167   struct X {
 168     virtual void f() = 0;
 169   };
 170   struct Y {};
 171   // CHECK-LABEL: define {{.*}} @_ZN5test51f
 172   void f(Y &y, X Y::*p) {
 173     // CHECK-NOT: call {{.*}} @_ZN5test51X1fEv
 174     // CHECK: call void %
 175     (y.*p).f();
 176   };
 177
 178   struct Z final {
 179     virtual void f() = 0;
 180   };
 181   // CHECK-LABEL: define {{.*}} @_ZN5test51g
 182   void g(Z &z) {
 183     // CHECK-NOT: call {{.*}} @_ZN5test51Z1fEv
 184     // CHECK: call void %
 185     z.f();
 186   }
 187
 188   struct Q {
 189     virtual void f() final = 0;
 190   };
 191   // CHECK-LABEL: define {{.*}} @_ZN5test51h
 192   void h(Q &q) {
 193     // CHECK-NOT: call {{.*}} @_ZN5test51Q1fEv
 194     // CHECK: call void %
 195     q.f();
 196   }
 197 }