clang/test/CodeGenCXX/bitfield-layout.cpp

   1 // RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o - -O3 | FileCheck -check-prefix=CHECK -check-prefix=CHECK-LP64 %s
   2 // RUN: %clang_cc1 %s -triple=i386-apple-darwin10 -emit-llvm -o - -O3 | FileCheck %s
   3 // RUN: %clang_cc1 %s -triple=aarch64_be -emit-llvm -o - -O3 | FileCheck %s
   4 // RUN: %clang_cc1 %s -triple=thumbv7_be-none-eabi -emit-llvm -o - -O3 | FileCheck %s
   5 // RUN: %clang_cc1 %s -triple=x86_64-unknown-unknown -emit-llvm -o - -O3 -std=c++11 | FileCheck -check-prefix=CHECK -check-prefix=CHECK-LP64 %s
   6
   7 // CHECK-LP64: %union.Test1 = type { i32, [4 x i8] }
   8 union Test1 {
   9   int a;
  10   int b: 39;
  11 };
  12 Test1 t1;
  13
  14 // CHECK-LP64: %union.Test2 = type { i8 }
  15 union Test2 {
  16   int : 6;
  17 } t2;
  18
  19 // CHECK-LP64: %union.Test3 = type { i16 }
  20 union Test3 {
  21   int : 9;
  22 } t3;
  23
  24 // CHECK: %union.Test4 = type { i8, i8 }
  25 union Test4 {
  26   char val : 16;
  27 };
  28 Test4 t4;
  29
  30 #define CHECK(x) if (!(x)) return __LINE__
  31
  32 // CHECK: define{{.*}} i32 @_Z11test_assignv()
  33 int test_assign() {
  34   struct {
  35     int a;
  36
  37     unsigned long long b : 65;
  38
  39     int c;
  40   } c;
  41
  42   c.a = 0;
  43   c.b = (unsigned long long)-1;
  44   c.c = 0;
  45
  46   CHECK(c.a == 0);
  47   CHECK(c.b == (unsigned long long)-1);
  48   CHECK(c.c == 0);
  49
  50   Test1 u1;
  51   Test4 u2;
  52
  53   u1.b = 1;
  54   u2.val = 42;
  55
  56   CHECK(u1.b == 1);
  57   CHECK(u2.val == 42);
  58
  59   // CHECK: ret i32 0
  60   return 0;
  61 }
  62
  63 // CHECK: define{{.*}} i32 @_Z9test_initv()
  64 int test_init() {
  65   struct S {
  66     int a;
  67
  68     unsigned long long b : 65;
  69
  70     int c;
  71   };
  72   S s1 = {1, 42, 0};
  73
  74   CHECK(s1.a == 1);
  75   CHECK(s1.b == (unsigned long long)42);
  76   CHECK(s1.c == 0);
  77
  78   Test1 u1 = {1};
  79   Test4 u2 = {42};
  80
  81   CHECK(u1.a == 1);
  82   CHECK(u1.b == 1);
  83   CHECK(u2.val == 42);
  84
  85   // CHECK: ret i32 0
  86   return 0;
  87 }
  88
  89 extern "C" {
  90 int test_trunc_int() {
  91   union {
  92     int i : 4; // truncated to 0b1111 == -1
  93   } const U = {15};  // 0b00001111
  94   return U.i;
  95 }
  96 // CHECK: define{{.*}} i32 @test_trunc_int()
  97 // CHECK: ret i32 -1
  98
  99 int test_trunc_three_bits() {
 100   union {
 101     int i : 3; // truncated to 0b111 == -1
 102   } const U = {15};  // 0b00001111
 103   return U.i;
 104 }
 105 // CHECK: define{{.*}} i32 @test_trunc_three_bits()
 106 // CHECK: ret i32 -1
 107
 108 int test_trunc_one_bit() {
 109   union {
 110     int i : 1; // truncated to 0b1 == -1
 111   } const U = {1};  // 0b00000001
 112   return U.i;
 113 }
 114 // CHECK: define{{.*}} i32 @test_trunc_one_bit()
 115 // CHECK: ret i32 -1
 116
 117 int test_trunc_1() {
 118   union {
 119     int i : 1; // truncated to 0b1 == -1
 120   } const U = {15};  // 0b00001111
 121   return U.i;
 122 }
 123 // CHECK: define{{.*}} i32 @test_trunc_1()
 124 // CHECK: ret i32 -1
 125
 126 int test_trunc_zero() {
 127   union {
 128     int i : 4; // truncated to 0b0000 == 0
 129   } const U = {80};  // 0b01010000
 130   return U.i;
 131 }
 132 // CHECK: define{{.*}} i32 @test_trunc_zero()
 133 // CHECK: ret i32 0
 134
 135 int test_constexpr() {
 136   union {
 137     int i : 3;           // truncated to 0b111 == -1
 138   } const U = {1 + 2 + 4 + 8}; // 0b00001111
 139   return U.i;
 140 }
 141 // CHECK: define{{.*}} i32 @test_constexpr()
 142 // CHECK: ret i32 -1
 143
 144 int test_notrunc() {
 145   union {
 146     int i : 12;          // not truncated
 147   } const U = {1 + 2 + 4 + 8}; // 0b00001111
 148   return U.i;
 149 }
 150 // CHECK: define{{.*}} i32 @test_notrunc()
 151 // CHECK: ret i32 15
 152
 153 long long test_trunc_long_long() {
 154   union {
 155     long long i : 14; // truncated to 0b00111101001101 ==
 156   } const U = {0b0100111101001101};
 157   return U.i;
 158 }
 159 // CHECK: define{{.*}} i64 @test_trunc_long_long()
 160 // CHECK: ret i64 3917
 161 }