]>
Commit | Line | Data |
---|---|---|
92a42be0 SL |
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 |