| //===------- dlwrap.h - Convenience wrapper around dlopen/dlsym -- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // The openmp plugins depend on extern libraries. These can be used via: |
| // - bitcode file statically linked |
| // - (relocatable) object file statically linked |
| // - static library |
| // - dynamic library, linked at build time |
| // - dynamic library, loaded at application run time by dlopen |
| // |
| // This file factors out most boilerplate for using a dlopened library. |
| // - Function symbols are generated that are statically linked against |
| // - The dlopen can be done implicitly when initializing the library |
| // - dlsym lookups are done once and cached |
| // - The abstraction is very thin to permit varied uses of the library |
| // |
| // Given int foo(char, double, void*);, writing DLWRAP(foo, 3) will expand to: |
| // int foo(char x0, double x1, void* x2) { |
| // constexpr size_t index = id(); |
| // void * dlsymResult = pointer(index); |
| // return ((int (*)(char, double, void*))dlsymResult)(x0, x1, x2); |
| // } |
| // |
| // Multiple calls to DLWRAP(symbol_name, arity) with bespoke |
| // initialization code that can use the thin abstraction: |
| // namespace dlwrap { |
| // static size_t size(); |
| // static const char *symbol(size_t); |
| // static void **pointer(size_t); |
| // } |
| // will compile to an object file that only exposes the symbols that the |
| // dynamic library would do, with the right function types. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef DLWRAP_H_INCLUDED |
| #define DLWRAP_H_INCLUDED |
| |
| #include <array> |
| #include <cstddef> |
| #include <tuple> |
| #include <type_traits> |
| |
| // Where symbol is a function, these expand to some book keeping and an |
| // implementation of that function |
| #define DLWRAP(SYMBOL, ARITY) DLWRAP_IMPL(SYMBOL, ARITY) |
| #define DLWRAP_INTERNAL(SYMBOL, ARITY) DLWRAP_INTERNAL_IMPL(SYMBOL, ARITY) |
| |
| // For example, given a prototype: |
| // int foo(char, double); |
| // |
| // DLWRAP(foo, 2) expands to: |
| // |
| // namespace dlwrap { |
| // struct foo_Trait : public dlwrap::trait<decltype(&foo)> { |
| // using T = dlwrap::trait<decltype(&foo)>; |
| // static T::FunctionType get() { |
| // constexpr size_t Index = getIndex(); |
| // void *P = *dlwrap::pointer(Index); |
| // return reinterpret_cast<T::FunctionType>(P); |
| // } |
| // }; |
| // } |
| // int foo(char x0, double x1) { return dlwrap::foo_Trait::get()(x0, x1); } |
| // |
| // DLWRAP_INTERNAL is similar, except the function it expands to is: |
| // static int dlwrap_foo(char x0, double x1) { ... } |
| // so that the function pointer call can be wrapped in library-specific code |
| |
| // DLWRAP_FINALIZE() expands to definitions of: |
| #define DLWRAP_FINALIZE() DLWRAP_FINALIZE_IMPL() |
| namespace dlwrap { |
| static size_t size(); |
| static const char *symbol(size_t); // get symbol name in [0, size()) |
| static void **pointer(size_t); // get pointer to function pointer in [0, size()) |
| } // namespace dlwrap |
| |
| // Implementation details follow. |
| |
| namespace dlwrap { |
| |
| // Extract return / argument types from address of function symbol |
| template <typename F> struct trait; |
| template <typename R, typename... Ts> struct trait<R (*)(Ts...)> { |
| constexpr static const size_t nargs = sizeof...(Ts); |
| typedef R ReturnType; |
| template <size_t i> struct arg { |
| typedef typename std::tuple_element<i, std::tuple<Ts...>>::type type; |
| }; |
| |
| typedef R (*FunctionType)(Ts...); |
| }; |
| |
| namespace type { |
| // Book keeping is by type specialization |
| |
| template <size_t S> struct count { |
| static constexpr size_t N = count<S - 1>::N; |
| }; |
| |
| template <> struct count<0> { static constexpr size_t N = 0; }; |
| |
| // Get a constexpr size_t ID, starts at zero |
| #define DLWRAP_ID() (dlwrap::type::count<__LINE__>::N) |
| |
| // Increment value returned by DLWRAP_ID |
| #define DLWRAP_INC() \ |
| template <> struct dlwrap::type::count<__LINE__> { \ |
| static constexpr size_t N = 1 + dlwrap::type::count<__LINE__ - 1>::N; \ |
| } |
| |
| template <size_t N> struct symbol; |
| #define DLWRAP_SYMBOL(SYMBOL, ID) \ |
| template <> struct dlwrap::type::symbol<ID> { \ |
| static constexpr const char *call() { return #SYMBOL; } \ |
| } |
| } // namespace type |
| |
| template <size_t N, size_t... Is> |
| constexpr std::array<const char *, N> static getSymbolArray( |
| std::index_sequence<Is...>) { |
| return {{dlwrap::type::symbol<Is>::call()...}}; |
| } |
| |
| } // namespace dlwrap |
| |
| #define DLWRAP_INSTANTIATE(SYM_USE, SYM_DEF, ARITY) \ |
| DLWRAP_INSTANTIATE_##ARITY(SYM_USE, SYM_DEF, \ |
| dlwrap::trait<decltype(&SYM_USE)>) |
| |
| #define DLWRAP_FINALIZE_IMPL() \ |
| static size_t dlwrap::size() { return DLWRAP_ID(); } \ |
| static const char *dlwrap::symbol(size_t i) { \ |
| static constexpr const std::array<const char *, DLWRAP_ID()> \ |
| dlwrap_symbols = getSymbolArray<DLWRAP_ID()>( \ |
| std::make_index_sequence<DLWRAP_ID()>()); \ |
| return dlwrap_symbols[i]; \ |
| } \ |
| static void **dlwrap::pointer(size_t i) { \ |
| static std::array<void *, DLWRAP_ID()> dlwrap_pointers; \ |
| return &dlwrap_pointers.data()[i]; \ |
| } |
| |
| #define DLWRAP_COMMON(SYMBOL, ARITY) \ |
| DLWRAP_INC(); \ |
| DLWRAP_SYMBOL(SYMBOL, DLWRAP_ID() - 1); \ |
| namespace dlwrap { \ |
| struct SYMBOL##_Trait : public dlwrap::trait<decltype(&SYMBOL)> { \ |
| using T = dlwrap::trait<decltype(&SYMBOL)>; \ |
| static T::FunctionType get() { \ |
| constexpr size_t Index = DLWRAP_ID() - 1; \ |
| void *P = *dlwrap::pointer(Index); \ |
| return reinterpret_cast<T::FunctionType>(P); \ |
| } \ |
| }; \ |
| } |
| |
| #define DLWRAP_IMPL(SYMBOL, ARITY) \ |
| DLWRAP_COMMON(SYMBOL, ARITY); \ |
| DLWRAP_INSTANTIATE(SYMBOL, SYMBOL, ARITY) |
| |
| #define DLWRAP_INTERNAL_IMPL(SYMBOL, ARITY) \ |
| DLWRAP_COMMON(SYMBOL, ARITY); \ |
| static DLWRAP_INSTANTIATE(SYMBOL, dlwrap_##SYMBOL, ARITY) |
| |
| #define DLWRAP_INSTANTIATE_0(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF() { return dlwrap::SYM_USE##_Trait::get()(); } |
| #define DLWRAP_INSTANTIATE_1(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0); \ |
| } |
| #define DLWRAP_INSTANTIATE_2(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1); \ |
| } |
| #define DLWRAP_INSTANTIATE_3(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2); \ |
| } |
| #define DLWRAP_INSTANTIATE_4(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2, \ |
| typename T::template arg<3>::type x3) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2, x3); \ |
| } |
| #define DLWRAP_INSTANTIATE_5(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2, \ |
| typename T::template arg<3>::type x3, \ |
| typename T::template arg<4>::type x4) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2, x3, x4); \ |
| } |
| #define DLWRAP_INSTANTIATE_6(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2, \ |
| typename T::template arg<3>::type x3, \ |
| typename T::template arg<4>::type x4, \ |
| typename T::template arg<5>::type x5) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2, x3, x4, x5); \ |
| } |
| |
| #define DLWRAP_INSTANTIATE_7(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2, \ |
| typename T::template arg<3>::type x3, \ |
| typename T::template arg<4>::type x4, \ |
| typename T::template arg<5>::type x5, \ |
| typename T::template arg<6>::type x6) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2, x3, x4, x5, x6); \ |
| } |
| |
| #define DLWRAP_INSTANTIATE_8(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2, \ |
| typename T::template arg<3>::type x3, \ |
| typename T::template arg<4>::type x4, \ |
| typename T::template arg<5>::type x5, \ |
| typename T::template arg<6>::type x6, \ |
| typename T::template arg<7>::type x7) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2, x3, x4, x5, x6, x7); \ |
| } |
| #define DLWRAP_INSTANTIATE_9(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2, \ |
| typename T::template arg<3>::type x3, \ |
| typename T::template arg<4>::type x4, \ |
| typename T::template arg<5>::type x5, \ |
| typename T::template arg<6>::type x6, \ |
| typename T::template arg<7>::type x7, \ |
| typename T::template arg<8>::type x8) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2, x3, x4, x5, x6, x7, x8); \ |
| } |
| #define DLWRAP_INSTANTIATE_10(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2, \ |
| typename T::template arg<3>::type x3, \ |
| typename T::template arg<4>::type x4, \ |
| typename T::template arg<5>::type x5, \ |
| typename T::template arg<6>::type x6, \ |
| typename T::template arg<7>::type x7, \ |
| typename T::template arg<8>::type x8, \ |
| typename T::template arg<9>::type x9) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2, x3, x4, x5, x6, x7, x8, \ |
| x9); \ |
| } |
| #define DLWRAP_INSTANTIATE_11(SYM_USE, SYM_DEF, T) \ |
| T::ReturnType SYM_DEF(typename T::template arg<0>::type x0, \ |
| typename T::template arg<1>::type x1, \ |
| typename T::template arg<2>::type x2, \ |
| typename T::template arg<3>::type x3, \ |
| typename T::template arg<4>::type x4, \ |
| typename T::template arg<5>::type x5, \ |
| typename T::template arg<6>::type x6, \ |
| typename T::template arg<7>::type x7, \ |
| typename T::template arg<8>::type x8, \ |
| typename T::template arg<9>::type x9, \ |
| typename T::template arg<10>::type x10) { \ |
| return dlwrap::SYM_USE##_Trait::get()(x0, x1, x2, x3, x4, x5, x6, x7, x8, \ |
| x9, x10); \ |
| } |
| |
| #endif |
