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// RUN: %clang_analyze_cc1 -analyzer-checker=alpha.core.PointerSub -analyzer-output=text -verify %s
void negative_1() {
int a[3];
int x = -1;
// FIXME: should indicate that 'x' is -1
int d = &a[x] - &a[0]; // expected-warning{{Using a negative array index at pointer subtraction is undefined behavior}} \
// expected-note{{Using a negative array index at pointer subtraction is undefined behavior}}
}
void negative_2() {
int a[3];
int *p1 = a, *p2 = a;
--p2;
// FIXME: should indicate that 'p2' is negative
int d = p1 - p2; // expected-warning{{Using a negative array index at pointer subtraction is undefined behavior}} \
// expected-note{{Using a negative array index at pointer subtraction is undefined behavior}}
}
void different_1() {
int a[3]; // expected-note{{Array at the left-hand side of subtraction}}
int b[3]; // expected-note{{Array at the right-hand side of subtraction}}
int d = &a[2] - &b[0]; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
// expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
}
void different_2() {
int a[3]; // expected-note{{Array at the right-hand side of subtraction}}
int b[3]; // expected-note{{Array at the left-hand side of subtraction}}
int *p1 = a + 1;
int *p2 = b;
int d = p2 - p1; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
// expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
}
int different_3() {
struct {
int array[5];
} a, b;
return &a.array[3] - &b.array[2]; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
// expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
}
int different_4() {
struct {
int array1[5]; // expected-note{{Array at the left-hand side of subtraction}}
int array2[5]; // expected-note{{Array at the right-hand side of subtraction}}
} a;
return &a.array1[3] - &a.array2[4]; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
// expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
}
void different_5() {
int d;
static int x[10][10]; // expected-note2{{Array at the left-hand side of subtraction}}
int *y1 = &(x[3][5]);
char *z = ((char *) y1) + 2;
int *y2 = (int *)(z - 2);
int *y3 = ((int *)x) + 35; // This is offset for [3][5].
d = y2 - y1; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
// expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
d = y3 - y1; // expected-warning{{Subtraction of two pointers that do not point into the same array is undefined behavior}} \
// expected-note{{Subtraction of two pointers that do not point into the same array is undefined behavior}}
d = y3 - y2;
}
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