test/SemaCXX/array-bounds.cpp

   1 // RUN: %clang_cc1 -verify %s
   2
   3 int foo() {
   4   int x[2]; // expected-note 4 {{array 'x' declared here}}
   5   int y[2]; // expected-note 2 {{array 'y' declared here}}
   6   int *p = &y[2]; // no-warning
   7   (void) sizeof(x[2]); // no-warning
   8   y[2] = 2; // expected-warning {{array index of '2' indexes past the end of an array (that contains 2 elements)}}
   9   return x[2] +  // expected-warning {{array index of '2' indexes past the end of an array (that contains 2 elements)}}
  10          y[-1] + // expected-warning {{array index of '-1' indexes before the beginning of the array}}
  11          x[sizeof(x)] +  // expected-warning {{array index of '8' indexes past the end of an array (that contains 2 elements)}}
  12          x[sizeof(x) / sizeof(x[0])] +  // expected-warning {{array index of '2' indexes past the end of an array (that contains 2 elements)}}
  13          x[sizeof(x) / sizeof(x[0]) - 1] + // no-warning
  14          x[sizeof(x[2])]; // expected-warning {{array index of '4' indexes past the end of an array (that contains 2 elements)}}
  15 }
  16
  17 // This code example tests that -Warray-bounds works with arrays that
  18 // are template parameters.
  19 template <char *sz> class Qux {
  20   bool test() { return sz[0] == 'a'; }
  21 };
  22
  23 void f1(int a[1]) {
  24   int val = a[3]; // no warning for function argumnet
  25 }
  26
  27 void f2(const int (&a)[1]) { // expected-note {{declared here}}
  28   int val = a[3];  // expected-warning {{array index of '3' indexes past the end of an array (that contains 1 elements)}}
  29 }
  30
  31 void test() {
  32   struct {
  33     int a[0];
  34   } s2;
  35   s2.a[3] = 0; // no warning for 0-sized array
  36
  37   union {
  38     short a[2]; // expected-note {{declared here}}
  39     char c[4];
  40   } u;
  41   u.a[3] = 1; // expected-warning {{array index of '3' indexes past the end of an array (that contains 2 elements)}}
  42   u.c[3] = 1; // no warning
  43
  44   const int const_subscript = 3;
  45   int array[1]; // expected-note {{declared here}}
  46   array[const_subscript] = 0;  // expected-warning {{array index of '3' indexes past the end of an array (that contains 1 elements)}}
  47
  48   int *ptr;
  49   ptr[3] = 0; // no warning for pointer references
  50   int array2[] = { 0, 1, 2 }; // expected-note 2 {{declared here}}
  51
  52   array2[3] = 0; // expected-warning {{array index of '3' indexes past the end of an array (that contains 3 elements)}}
  53   array2[2+2] = 0; // expected-warning {{array index of '4' indexes past the end of an array (that contains 3 elements)}}
  54
  55   const char *str1 = "foo";
  56   char c1 = str1[5]; // no warning for pointers
  57
  58   const char str2[] = "foo"; // expected-note {{declared here}}
  59   char c2 = str2[5]; // expected-warning {{array index of '5' indexes past the end of an array (that contains 4 elements)}}
  60
  61   int (*array_ptr)[1];
  62   (*array_ptr)[3] = 1; // expected-warning {{array index of '3' indexes past the end of an array (that contains 1 elements)}}
  63 }
  64
  65 template <int I> struct S {
  66   char arr[I]; // expected-note 3 {{declared here}}
  67 };
  68 template <int I> void f() {
  69   S<3> s;
  70   s.arr[4] = 0; // expected-warning 2 {{array index of '4' indexes past the end of an array (that contains 3 elements)}}
  71   s.arr[I] = 0; // expected-warning {{array index of '5' indexes past the end of an array (that contains 3 elements)}}
  72 }
  73
  74 void test_templates() {
  75   f<5>(); // expected-note {{in instantiation}}
  76 }
  77
  78 #define SIZE 10
  79 #define ARR_IN_MACRO(flag, arr, idx) flag ? arr[idx] : 1
  80
  81 int test_no_warn_macro_unreachable() {
  82   int arr[SIZE]; // expected-note 2 {{array 'arr' declared here}}
  83   // FIXME: We don't want to warn for the first case.
  84   return ARR_IN_MACRO(0, arr, SIZE) + // expected-warning{{array index of '10' indexes past the end of an array (that contains 10 elements)}}
  85          ARR_IN_MACRO(1, arr, SIZE); // expected-warning{{array index of '10' indexes past the end of an array (that contains 10 elements)}}
  86 }
  87
  88 // This exhibited an assertion failure for a 32-bit build of Clang.
  89 int test_pr9240() {
  90   short array[100]; // expected-note {{array 'array' declared here}}
  91   return array[(unsigned long long) 100]; // expected-warning {{array index of '100' indexes past the end of an array (that contains 100 elements)}}
  92 }
  93