clang/test/SemaCXX/builtin-object-size-cxx14.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx14 -std=c++14 %s
   2 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++2a %s
   3
   4 typedef __SIZE_TYPE__ size_t;
   5
   6 namespace basic {
   7 // Ensuring that __bos can be used in constexpr functions without anything
   8 // sketchy going on...
   9 constexpr int bos0() {
  10   int k = 5;
  11   char cs[10] = {};
  12   return __builtin_object_size(&cs[k], 0);
  13 }
  14
  15 constexpr int bos1() {
  16   int k = 5;
  17   char cs[10] = {};
  18   return __builtin_object_size(&cs[k], 1);
  19 }
  20
  21 constexpr int bos2() {
  22   int k = 5;
  23   char cs[10] = {};
  24   return __builtin_object_size(&cs[k], 2);
  25 }
  26
  27 constexpr int bos3() {
  28   int k = 5;
  29   char cs[10] = {};
  30   return __builtin_object_size(&cs[k], 3);
  31 }
  32
  33 static_assert(bos0() == sizeof(char) * 5, "");
  34 static_assert(bos1() == sizeof(char) * 5, "");
  35 static_assert(bos2() == sizeof(char) * 5, "");
  36 static_assert(bos3() == sizeof(char) * 5, "");
  37 }
  38
  39 namespace in_enable_if {
  40 // The code that prompted these changes was __bos in enable_if
  41
  42 void copy5CharsInto(char *buf) // expected-note{{candidate}}
  43     __attribute__((enable_if(__builtin_object_size(buf, 0) != -1 &&
  44                                  __builtin_object_size(buf, 0) > 5,
  45                              "")));
  46
  47 // We use different EvalModes for __bos with type 0 versus 1. Ensure 1 works,
  48 // too...
  49 void copy5CharsIntoStrict(char *buf) // expected-note{{candidate}}
  50     __attribute__((enable_if(__builtin_object_size(buf, 1) != -1 &&
  51                                  __builtin_object_size(buf, 1) > 5,
  52                              "")));
  53
  54 struct LargeStruct {
  55   int pad;
  56   char buf[6];
  57   int pad2;
  58 };
  59
  60 struct SmallStruct {
  61   int pad;
  62   char buf[5];
  63   int pad2;
  64 };
  65
  66 void noWriteToBuf() {
  67   char buf[6];
  68   copy5CharsInto(buf);
  69
  70   LargeStruct large;
  71   copy5CharsIntoStrict(large.buf);
  72 }
  73
  74 void initTheBuf() {
  75   char buf[6] = {};
  76   copy5CharsInto(buf);
  77
  78   LargeStruct large = {0, {}, 0};
  79   copy5CharsIntoStrict(large.buf);
  80 }
  81
  82 int getI();
  83 void initTheBufWithALoop() {
  84   char buf[6] = {};
  85   for (unsigned I = getI(); I != sizeof(buf); ++I)
  86     buf[I] = I;
  87   copy5CharsInto(buf);
  88
  89   LargeStruct large;
  90   for (unsigned I = getI(); I != sizeof(buf); ++I)
  91     large.buf[I] = I;
  92   copy5CharsIntoStrict(large.buf);
  93 }
  94
  95 void tooSmallBuf() {
  96   char buf[5];
  97   copy5CharsInto(buf); // expected-error{{no matching function for call}}
  98
  99   SmallStruct small;
 100   copy5CharsIntoStrict(small.buf); // expected-error{{no matching function for call}}
 101 }
 102 }
 103
 104 namespace InvalidBase {
 105   // Ensure this doesn't crash.
 106   struct S { const char *name; };
 107   S invalid_base();
 108   constexpr size_t bos_name = __builtin_object_size(invalid_base().name, 1);
 109   static_assert(bos_name == -1, "");
 110
 111   struct T { ~T(); };
 112   T invalid_base_2();
 113   constexpr size_t bos_dtor = __builtin_object_size(&(T&)(T&&)invalid_base_2(), 0);
 114   static_assert(bos_dtor == -1, "");
 115 }
 116
 117 // PR44268
 118 constexpr int bos_new() { // cxx14-error {{constant expression}}
 119   void *p = new int; // cxx14-note {{until C++20}}
 120   return __builtin_object_size(p, 0);
 121 }