compiler-rt/test/cfi/utils.h

   1 #ifndef UTILS_H
   2 #define UTILS_H
   3
   4 inline void break_optimization(void *arg) {
   5   __asm__ __volatile__("" : : "r" (arg) : "memory");
   6 }
   7
   8 // Tests will instantiate this class to pad out bit sets to test out the
   9 // various ways we can represent the bit set (32-bit inline, 64-bit inline,
  10 // memory). Instantiating this class will trigger the instantiation of I
  11 // templates with I virtual tables for classes deriving from T, I-2 of which
  12 // will be of size sizeof(void*) * 5, 1 of which will be of size sizeof(void*)
  13 // * 3, and 1 of which will be of size sizeof(void*) * 9. (Under the MS ABI
  14 // each virtual table will be sizeof(void*) bytes smaller). Each category
  15 // of virtual tables is aligned to a different power of 2, precluding the
  16 // all-ones optimization. As a result, the bit vector for the base class will
  17 // need to contain at least I*2 entries to accommodate all the derived virtual
  18 // tables.
  19 template <typename T, unsigned I>
  20 struct Deriver : T {
  21   Deriver() {
  22     break_optimization(new Deriver<T, I-1>);
  23   }
  24   virtual void f() {}
  25   virtual void g() {}
  26   virtual void h() {}
  27 };
  28
  29 template <typename T>
  30 struct Deriver<T, 0> : T {
  31   virtual void f() {}
  32   void g() {}
  33 };
  34
  35 template <typename T>
  36 struct Deriver<T, 1> : T {
  37   Deriver() {
  38     break_optimization(new Deriver<T, 0>);
  39   }
  40   virtual void f() {}
  41   virtual void g() {}
  42   virtual void h() {}
  43   virtual void i() {}
  44   virtual void j() {}
  45   virtual void k() {}
  46   virtual void l() {}
  47 };
  48
  49 // Instantiate enough classes to force CFI checks for type T to use bit
  50 // vectors of size 32 (if B32 defined), 64 (if B64 defined) or >64 (if BM
  51 // defined).
  52 template <typename T>
  53 void create_derivers() {
  54 #ifdef B32
  55   break_optimization(new Deriver<T, 10>);
  56 #endif
  57
  58 #ifdef B64
  59   break_optimization(new Deriver<T, 25>);
  60 #endif
  61
  62 #ifdef BM
  63   break_optimization(new Deriver<T, 40>);
  64 #endif
  65 }
  66
  67 #endif