gcc/testsuite/gcc.dg/Walloca-1.c

   1 /* { dg-do compile } */
   2 /* { dg-require-effective-target alloca } */
   3 /* { dg-options "-Walloca-larger-than=2000 -O2 -ftrack-macro-expansion=0" } */
   4
   5 #define alloca __builtin_alloca
   6
   7 typedef __SIZE_TYPE__ size_t;
   8 extern size_t strlen(const char *);
   9
  10 extern void useit (char *);
  11
  12 int num;
  13
  14 void foo1 (size_t len, size_t len2, size_t len3)
  15 {
  16   int i;
  17
  18   for (i=0; i < 123; ++i)
  19     {
  20       char *s = alloca (566);   /* { dg-warning "'alloca' within a loop" } */
  21       useit (s);
  22     }
  23
  24   char *s = alloca (123);
  25   useit (s);                    // OK, constant argument to alloca
  26
  27   s = alloca (num);             // { dg-warning "\(may be too large|unbounded use\)" }
  28   useit (s);
  29
  30   s = alloca (30000);           /* { dg-warning "is too large" } */
  31   useit (s);
  32
  33   if (len < 2000)
  34     {
  35       s = alloca(len);          // OK, bounded
  36       useit (s);
  37     }
  38
  39   if (len + len2 < 2000)        // OK, bounded
  40     {
  41       s = alloca(len + len2);
  42       useit (s);
  43     }
  44
  45   if (len3 <= 2001)
  46     {
  47       s = alloca(len3);         /* { dg-warning "may be too large" } */
  48       useit(s);
  49     }
  50 }
  51
  52 void foo2 (__SIZE_TYPE__ len)
  53 {
  54   // Test that a direct call to __builtin_alloca_with_align is not confused
  55   // with a VLA.
  56   void *p = __builtin_alloca_with_align (len, 8); // { dg-warning "unbounded use of 'alloca'" }
  57   useit (p);
  58 }
  59
  60 void foo3 (unsigned char a)
  61 {
  62   if (a == 0)
  63     useit (__builtin_alloca (a)); // { dg-warning "argument to 'alloca' is zero" }
  64 }