clang/test/CodeGen/union-init.c

   1 // RUN: %clang_cc1 -emit-llvm < %s -o -
   2
   3 // A nice and complicated initialization example with unions from Python
   4 typedef int Py_ssize_t;
   5
   6 typedef union _gc_head {
   7   struct {
   8     union _gc_head *gc_next;
   9     union _gc_head *gc_prev;
  10     Py_ssize_t gc_refs;
  11   } gc;
  12   long double dummy;  /* force worst-case alignment */
  13 } PyGC_Head;
  14
  15 struct gc_generation {
  16   PyGC_Head head;
  17   int threshold; /* collection threshold */
  18   int count;     /* count of allocations or collections of younger
  19                     generations */
  20 };
  21
  22 #define NUM_GENERATIONS 3
  23 #define GEN_HEAD(n) (&generations[n].head)
  24
  25 /* linked lists of container objects */
  26 struct gc_generation generations[NUM_GENERATIONS] = {
  27   /* PyGC_Head,                     threshold,      count */
  28   {{{GEN_HEAD(0), GEN_HEAD(0), 0}}, 700,            0},
  29   {{{GEN_HEAD(1), GEN_HEAD(1), 0}},  10,            0},
  30   {{{GEN_HEAD(2), GEN_HEAD(2), 0}},  10,            0},
  31 };