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shove the stack alloc stuff into detail:: (for potential reuse elsewhere)

master
Daniel Kolesa 2017-03-09 00:25:51 +01:00
parent 8e97f7fdfd
commit fb592f8c2c
1 changed files with 67 additions and 59 deletions
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126
ostd/context_stack.hh
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@ -46,23 +46,6 @@
namespace ostd {
namespace detail {
#ifdef OSTD_PLATFORM_POSIX
# if defined(MAP_ANON) || defined(MAP_ANONYMOUS)
constexpr bool CONTEXT_USE_MMAP = true;
# ifdef MAP_ANON
constexpr auto CONTEXT_MAP_ANON = MAP_ANON;
# else
constexpr auto CONTEXT_MAP_ANON = MAP_ANONYMOUS;
# endif
# else
constexpr bool CONTEXT_USE_MMAP = false;
# endif
#endif
} /* namespace detail */
struct stack_context {
#ifdef OSTD_USE_SEGMENTED_STACKS
using segments_context = void *[OSTD_CONTEXT_SEGMENTS];
@ -154,6 +137,69 @@ struct stack_traits {
}
};
namespace detail {
#ifdef OSTD_PLATFORM_POSIX
# if defined(MAP_ANON) || defined(MAP_ANONYMOUS)
constexpr bool CONTEXT_USE_MMAP = true;
# ifdef MAP_ANON
constexpr auto CONTEXT_MAP_ANON = MAP_ANON;
# else
constexpr auto CONTEXT_MAP_ANON = MAP_ANONYMOUS;
# endif
# else
constexpr bool CONTEXT_USE_MMAP = false;
# endif
#endif
inline void *stack_alloc(size_t sz) {
#if defined(OSTD_PLATFORM_WIN32)
void *p = VirtualAlloc(0, sz, MEM_COMMIT, PAGE_READWRITE);
if (!p) {
throw std::bad_alloc{}
}
return p;
#elif defined(OSTD_PLATFORM_POSIX)
if constexpr(CONTEXT_USE_MMAP) {
void *p = mmap(
0, sz, PROT_READ | PROT_WRITE,
MAP_PRIVATE | CONTEXT_MAP_ANON, -1, 0
);
if (p == MAP_FAILED) {
throw std::bad_alloc{};
}
return p;
}
void *p = std::malloc(sz);
if (!p) {
throw std::bad_alloc{};
}
return p;
#endif
}
inline void stack_free(void *p, size_t sz) {
#if defined(OSTD_PLATFORM_WIN32)
(void)sz;
VirtualFree(p, 0, MEM_RELEASE);
#elif defined(OSTD_PLATFORM_POSIX)
if constexpr(CONTEXT_USE_MMAP) {
munmap(p, sz);
} else {
std::free(p);
}
#endif
}
inline void stack_protect(void *p, size_t sz) {
#if defined(OSTD_PLATFORM_WIN32)
DWORD oo;
VirtualProtect(p, sz, PAGE_READWRITE | PAGE_GUARD, &oo);
#elif defined(OSTD_PLATFORM_POSIX)
mprotect(p, sz, PROT_NONE);
#endif
}
}
template<typename TR, bool Protected>
struct basic_fixedsize_stack {
using traits_type = TR;
@ -170,42 +216,16 @@ struct basic_fixedsize_stack {
size_t npg = std::max(ss / pgs, size_t(size_t(Protected) + 1));
size_t asize = npg * pgs;
#if defined(OSTD_PLATFORM_WIN32)
void *p = VirtualAlloc(0, asize, MEM_COMMIT, PAGE_READWRITE);
if (!p) {
throw std::bad_alloc{}
}
DWORD oo;
void *p = detail::stack_alloc(asize);
if constexpr(Protected) {
VirtualProtect(p, pgs, PAGE_READWRITE | PAGE_GUARD, &oo);
/* a single guard page */
detail::stack_protect(p, pgs);
}
#elif defined(OSTD_PLATFORM_POSIX)
void *p = nullptr;
if constexpr(detail::CONTEXT_USE_MMAP) {
void *mp = mmap(
0, asize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | detail::CONTEXT_MAP_ANON, -1, 0
);
if (mp != MAP_FAILED) {
p = mp;
}
} else {
p = std::malloc(asize);
}
if (!p) {
throw std::bad_alloc{};
}
if constexpr(Protected) {
mprotect(p, pgs, PROT_NONE);
}
#endif
stack_context ret{static_cast<byte *>(p) + ss, ss};
#ifdef OSTD_USE_VALGRIND
ret.valgrind_id = VALGRIND_STACK_REGISTER(ret.ptr, p);
#endif
return ret;
}
@ -213,22 +233,10 @@ struct basic_fixedsize_stack {
if (!st.ptr) {
return;
}
#ifdef OSTD_USE_VALGRIND
VALGRIND_STACK_DEREGISTER(st.valgrind_id);
#endif
auto p = static_cast<byte *>(st.ptr) - st.size;
#if defined(OSTD_PLATFORM_WIN32)
VirtualFree(p, 0, MEM_RELEASE);
#elif defined(OSTD_PLATFORM_POSIX)
if constexpr(detail::CONTEXT_USE_MMAP) {
munmap(p, st.size);
} else {
std::free(p);
}
#endif
detail::stack_free(static_cast<byte *>(st.ptr) - st.size, st.size);
st.ptr = nullptr;
}