[dfsan] Test dfsan_flush with origins

[stephan.yichao.zhao]

Summary

This is a part of https://reviews.llvm.org/D95835.

[morehouse]

LGTM

compiler-rt/test/dfsan/flush.c

 // Tests dfsan_flush().
 // RUN: %clang_dfsan %s -o %t && %run %t
+// RUN: %clang_dfsan -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 -mllvm -dfsan-fast-16-labels=true %s -o %t && %run %t
 #include <sanitizer/dfsan_interface.h>
 #include <assert.h>
 #include <stdlib.h>
 
 int global;
 
 int main() {
   int local;
   int *heap = (int*)malloc(sizeof(int));
 
   dfsan_set_label(10, &global, sizeof(global));
   dfsan_set_label(20, &local, sizeof(local));
   dfsan_set_label(30, heap, sizeof(*heap));
 
   assert(dfsan_get_label(global) == 10);
   assert(dfsan_get_label(local) == 20);
   assert(dfsan_get_label(*heap) == 30);
+#ifdef ORIGIN_TRACKING
+  assert(dfsan_get_origin(global));
+  assert(dfsan_get_origin(local));
+  assert(dfsan_get_origin(*heap));
+#endif
 
   dfsan_flush();
 
   assert(dfsan_get_label(global) == 0);
   assert(dfsan_get_label(local) == 0);
   assert(dfsan_get_label(*heap) == 0);
+  assert(dfsan_get_origin(global) == 0);
+  assert(dfsan_get_origin(local) == 0);
+  assert(dfsan_get_origin(*heap) == 0);
 
   free(heap);
 }