llvm-project/clang/test/SemaCXX/array-bounds.cpp

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// RUN: %clang_cc1 -verify %s
int foo() {
int x[2]; // expected-note 4 {{array 'x' declared here}}
int y[2]; // expected-note 2 {{array 'y' declared here}}
int *p = &y[2]; // no-warning
(void) sizeof(x[2]); // no-warning
y[2] = 2; // expected-warning {{array index of '2' indexes past the end of an array (that contains 2 elements)}}
return x[2] + // expected-warning {{array index of '2' indexes past the end of an array (that contains 2 elements)}}
y[-1] + // expected-warning {{array index of '-1' indexes before the beginning of the array}}
x[sizeof(x)] + // expected-warning {{array index of '8' indexes past the end of an array (that contains 2 elements)}}
x[sizeof(x) / sizeof(x[0])] + // expected-warning {{array index of '2' indexes past the end of an array (that contains 2 elements)}}
x[sizeof(x) / sizeof(x[0]) - 1] + // no-warning
x[sizeof(x[2])]; // expected-warning {{array index of '4' indexes past the end of an array (that contains 2 elements)}}
}
// This code example tests that -Warray-bounds works with arrays that
// are template parameters.
template <char *sz> class Qux {
bool test() { return sz[0] == 'a'; }
};
void f1(int a[1]) {
int val = a[3]; // no warning for function argumnet
}
void f2(const int (&a)[2]) { // expected-note {{declared here}}
int val = a[3]; // expected-warning {{array index of '3' indexes past the end of an array (that contains 2 elements)}}
}
void test() {
struct {
int a[0];
} s2;
s2.a[3] = 0; // no warning for 0-sized array
union {
short a[2]; // expected-note {{declared here}}
char c[4];
} u;
u.a[3] = 1; // expected-warning {{array index of '3' indexes past the end of an array (that contains 2 elements)}}
u.c[3] = 1; // no warning
const int const_subscript = 3;
int array[2]; // expected-note {{declared here}}
array[const_subscript] = 0; // expected-warning {{array index of '3' indexes past the end of an array (that contains 2 elements)}}
int *ptr;
ptr[3] = 0; // no warning for pointer references
int array2[] = { 0, 1, 2 }; // expected-note 2 {{declared here}}
array2[3] = 0; // expected-warning {{array index of '3' indexes past the end of an array (that contains 3 elements)}}
array2[2+2] = 0; // expected-warning {{array index of '4' indexes past the end of an array (that contains 3 elements)}}
const char *str1 = "foo";
char c1 = str1[5]; // no warning for pointers
const char str2[] = "foo"; // expected-note {{declared here}}
char c2 = str2[5]; // expected-warning {{array index of '5' indexes past the end of an array (that contains 4 elements)}}
int (*array_ptr)[2];
(*array_ptr)[3] = 1; // expected-warning {{array index of '3' indexes past the end of an array (that contains 2 elements)}}
}
template <int I> struct S {
char arr[I]; // expected-note 2 {{declared here}}
};
template <int I> void f() {
S<3> s;
s.arr[4] = 0; // expected-warning {{array index of '4' indexes past the end of an array (that contains 3 elements)}}
s.arr[I] = 0; // expected-warning {{array index of '5' indexes past the end of an array (that contains 3 elements)}}
}
void test_templates() {
f<5>(); // expected-note {{in instantiation}}
}
#define SIZE 10
#define ARR_IN_MACRO(flag, arr, idx) flag ? arr[idx] : 1
int test_no_warn_macro_unreachable() {
int arr[SIZE]; // expected-note {{array 'arr' declared here}}
return ARR_IN_MACRO(0, arr, SIZE) + // no-warning
ARR_IN_MACRO(1, arr, SIZE); // expected-warning{{array index of '10' indexes past the end of an array (that contains 10 elements)}}
}
// This exhibited an assertion failure for a 32-bit build of Clang.
int test_pr9240() {
short array[100]; // expected-note {{array 'array' declared here}}
return array[(unsigned long long) 100]; // expected-warning {{array index of '100' indexes past the end of an array (that contains 100 elements)}}
}
// PR 9284 - a template parameter can cause an array bounds access to be
// infeasible.
template <bool extendArray>
void pr9284() {
int arr[3 + (extendArray ? 1 : 0)];
if (extendArray)
arr[3] = 42; // no-warning
}
template <bool extendArray>
void pr9284b() {
int arr[3 + (extendArray ? 1 : 0)]; // expected-note {{array 'arr' declared here}}
if (!extendArray)
arr[3] = 42; // expected-warning{{array index of '3' indexes past the end of an array (that contains 3 elements)}}
}
void test_pr9284() {
pr9284<true>();
pr9284<false>();
pr9284b<true>();
pr9284b<false>(); // expected-note{{in instantiation of function template specialization 'pr9284b<false>' requested here}}
}
int test_pr9296() {
int array[2];
return array[true]; // no-warning
}
int test_sizeof_as_condition(int flag) {
int arr[2] = { 0, 0 }; // expected-note {{array 'arr' declared here}}
if (flag)
return sizeof(char) != sizeof(char) ? arr[2] : arr[1];
return sizeof(char) == sizeof(char) ? arr[2] : arr[1]; // expected-warning {{array index of '2' indexes past the end of an array (that contains 2 elements)}}
}
void test_switch() {
switch (4) {
case 1: {
int arr[2];
arr[2] = 1; // no-warning
break;
}
case 4: {
int arr[2]; // expected-note {{array 'arr' declared here}}
arr[2] = 1; // expected-warning {{array index of '2' indexes past the end of an array (that contains 2 elements)}}
break;
}
default: {
int arr[2];
arr[2] = 1; // no-warning
break;
}
}
}
// Test nested switch statements.
enum enumA { enumA_A, enumA_B, enumA_C, enumA_D, enumA_E };
enum enumB { enumB_X, enumB_Y, enumB_Z };
static enum enumB myVal = enumB_X;
void test_nested_switch()
{
switch (enumA_E) { // expected-warning {{no case matching constant}}
switch (myVal) { // expected-warning {{enumeration values 'enumB_X' and 'enumB_Z' not handled in switch}}
case enumB_Y: ;
}
}
}
// Test that if all the values of an enum covered, that the 'default' branch
// is unreachable.
enum Values { A, B, C, D };
void test_all_enums_covered(enum Values v) {
int x[2];
switch (v) {
case A: return;
case B: return;
case C: return;
case D: return;
}
x[2] = 0; // no-warning
}
namespace tailpad {
struct foo {
int x;
char c[1];
};
char bar(struct foo *F) {
return F->c[3]; // no warning, foo could have tail padding allocated.
}
}