catch-nullptr-and-nonzero-offset-in-offsetof-idiom.cpp
793 Bytes
// RUN: %clang_cc1 -x c++ -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s
// RUN: %clang_cc1 -x c++ -fsanitize=pointer-overflow -fno-sanitize-recover=pointer-overflow -emit-llvm %s -o - -triple x86_64-linux-gnu | FileCheck %s
#include <stdint.h>
struct S {
int x, y;
};
// CHECK-LABEL: define i64 @{{.*}}get_offset_of_y_naively{{.*}}(
uintptr_t get_offset_of_y_naively() {
// CHECK: [[ENTRY:.*]]:
// CHECK-NEXT: ret i64 ptrtoint (i32* getelementptr (i32, i32* null, i32 1) to i64)
// CHECK-NEXT: }
return ((uintptr_t)(&(((S *)nullptr)->y)));
}
// CHECK-LABEL: define i64 @{{.*}}get_offset_of_y_via_builtin{{.*}}(
uintptr_t get_offset_of_y_via_builtin() {
// CHECK: [[ENTRY:.*]]:
// CHECK-NEXT: ret i64 4
// CHECK-NEXT: }
return __builtin_offsetof(S, y);
}