Stephen Hines | 86277eb | 2015-03-23 12:06:32 -0700 | [diff] [blame] | 1 | #ifndef UTILS_H |
| 2 | #define UTILS_H |
| 3 | |
| 4 | inline void break_optimization(void *arg) { |
| 5 | __asm__ __volatile__("" : : "r" (arg) : "memory"); |
| 6 | } |
| 7 | |
Pirama Arumuga Nainar | 799172d | 2016-03-03 15:50:30 -0800 | [diff] [blame^] | 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. |
Stephen Hines | 86277eb | 2015-03-23 12:06:32 -0700 | [diff] [blame] | 19 | template <typename T, unsigned I> |
Pirama Arumuga Nainar | 799172d | 2016-03-03 15:50:30 -0800 | [diff] [blame^] | 20 | struct Deriver : T { |
| 21 | Deriver() { |
| 22 | break_optimization(new Deriver<T, I-1>); |
| 23 | } |
Stephen Hines | 86277eb | 2015-03-23 12:06:32 -0700 | [diff] [blame] | 24 | virtual void f() {} |
| 25 | virtual void g() {} |
Pirama Arumuga Nainar | 799172d | 2016-03-03 15:50:30 -0800 | [diff] [blame^] | 26 | virtual void h() {} |
Stephen Hines | 86277eb | 2015-03-23 12:06:32 -0700 | [diff] [blame] | 27 | }; |
| 28 | |
Pirama Arumuga Nainar | 799172d | 2016-03-03 15:50:30 -0800 | [diff] [blame^] | 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 | |
Stephen Hines | 86277eb | 2015-03-23 12:06:32 -0700 | [diff] [blame] | 67 | #endif |