forked from OSchip/llvm-project
68 lines
1.8 KiB
C++
68 lines
1.8 KiB
C++
#ifndef UTILS_H
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#define UTILS_H
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inline void break_optimization(void *arg) {
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__asm__ __volatile__("" : : "r" (arg) : "memory");
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}
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// Tests will instantiate this class to pad out bit sets to test out the
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// various ways we can represent the bit set (32-bit inline, 64-bit inline,
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// memory). Instantiating this class will trigger the instantiation of I
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// templates with I virtual tables for classes deriving from T, I-2 of which
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// will be of size sizeof(void*) * 5, 1 of which will be of size sizeof(void*)
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// * 3, and 1 of which will be of size sizeof(void*) * 9. (Under the MS ABI
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// each virtual table will be sizeof(void*) bytes smaller). Each category
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// of virtual tables is aligned to a different power of 2, precluding the
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// all-ones optimization. As a result, the bit vector for the base class will
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// need to contain at least I*2 entries to accommodate all the derived virtual
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// tables.
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template <typename T, unsigned I>
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struct Deriver : T {
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Deriver() {
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break_optimization(new Deriver<T, I-1>);
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}
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virtual void f() {}
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virtual void g() {}
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virtual void h() {}
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};
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template <typename T>
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struct Deriver<T, 0> : T {
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virtual void f() {}
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void g() {}
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};
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template <typename T>
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struct Deriver<T, 1> : T {
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Deriver() {
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break_optimization(new Deriver<T, 0>);
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}
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virtual void f() {}
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virtual void g() {}
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virtual void h() {}
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virtual void i() {}
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virtual void j() {}
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virtual void k() {}
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virtual void l() {}
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};
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// Instantiate enough classes to force CFI checks for type T to use bit
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// vectors of size 32 (if B32 defined), 64 (if B64 defined) or >64 (if BM
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// defined).
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template <typename T>
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void create_derivers() {
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#ifdef B32
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break_optimization(new Deriver<T, 10>);
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#endif
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#ifdef B64
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break_optimization(new Deriver<T, 25>);
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#endif
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#ifdef BM
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break_optimization(new Deriver<T, 40>);
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#endif
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}
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#endif
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