| // RUN: %clang_cl_asan -Od %s -Fe%t | 
 | // RUN: not %run %t 2>&1 | FileCheck %s | 
 |  | 
 | #include <windows.h> | 
 |  | 
 | typedef struct _S { | 
 |   unsigned int bf1:1; | 
 |   unsigned int bf2:2; | 
 |   unsigned int bf3:3; | 
 |   unsigned int bf4:4; | 
 | } S; | 
 |  | 
 | void make_access(S *s) { | 
 |   s->bf2 = 2; | 
 | // CHECK: AddressSanitizer: heap-use-after-free on address [[ADDR:0x[0-9a-f]+]] | 
 | // CHECK: READ of size {{[124]}} at [[ADDR]] | 
 | // CHECK:   {{#0 .* make_access.*bitfield_uaf.cpp}}:[[@LINE-3]] | 
 | // CHECK:   {{#1 .* main}} | 
 | } | 
 |  | 
 | int main(void) { | 
 |   S *s = (S*)malloc(sizeof(S)); | 
 |   free(s); | 
 | // CHECK: [[ADDR]] is located 0 bytes inside of 4-byte region | 
 | // CHECK-LABEL: freed by thread T0 here: | 
 | // CHECK:   {{#0 .* free }} | 
 | // CHECK:   {{#1 .* main .*bitfield_uaf.cpp}}:[[@LINE-4]] | 
 | // CHECK-LABEL: previously allocated by thread T0 here: | 
 | // CHECK:   {{#0 .* malloc }} | 
 | // CHECK:   {{#1 .* main .*bitfield_uaf.cpp}}:[[@LINE-8]] | 
 |   make_access(s); | 
 |   return 0; | 
 | } | 
 |  |