76 lines
2.4 KiB
C++
76 lines
2.4 KiB
C++
//===--- generic-elf-64bit/dynamic_ffi/ffi.cpp -------------------- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Implement subset of the FFI api by calling into the FFI library via dlopen
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/DynamicLibrary.h"
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#include "Shared/Debug.h"
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#include <memory>
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#include "DLWrap.h"
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#include "ffi.h"
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DLWRAP_INITIALIZE()
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DLWRAP(ffi_call, 4);
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DLWRAP(ffi_prep_cif, 5);
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DLWRAP_FINALIZE()
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ffi_type ffi_type_void;
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ffi_type ffi_type_pointer;
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// Name of the FFI shared library.
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constexpr const char *FFI_PATH = "libffi.so";
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#define DYNAMIC_FFI_SUCCESS 0
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#define DYNAMIC_FFI_FAIL 1
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// Initializes the dynamic FFI wrapper.
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uint32_t ffi_init() {
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std::string ErrMsg;
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auto DynlibHandle = std::make_unique<llvm::sys::DynamicLibrary>(
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llvm::sys::DynamicLibrary::getPermanentLibrary(FFI_PATH, &ErrMsg));
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if (!DynlibHandle->isValid()) {
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DP("Unable to load library '%s': %s!\n", FFI_PATH, ErrMsg.c_str());
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return DYNAMIC_FFI_FAIL;
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}
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for (size_t I = 0; I < dlwrap::size(); I++) {
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const char *Sym = dlwrap::symbol(I);
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void *P = DynlibHandle->getAddressOfSymbol(Sym);
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if (P == nullptr) {
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DP("Unable to find '%s' in '%s'!\n", Sym, FFI_PATH);
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return DYNAMIC_FFI_FAIL;
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}
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DP("Implementing %s with dlsym(%s) -> %p\n", Sym, Sym, P);
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*dlwrap::pointer(I) = P;
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}
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#define DYNAMIC_INIT(SYMBOL) \
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{ \
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void *SymbolPtr = DynlibHandle->getAddressOfSymbol(#SYMBOL); \
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if (!SymbolPtr) { \
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DP("Unable to find '%s' in '%s'!\n", #SYMBOL, FFI_PATH); \
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return DYNAMIC_FFI_FAIL; \
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} \
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SYMBOL = *reinterpret_cast<decltype(SYMBOL) *>(SymbolPtr); \
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}
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DYNAMIC_INIT(ffi_type_void);
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DYNAMIC_INIT(ffi_type_pointer);
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#undef DYNAMIC_INIT
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return DYNAMIC_FFI_SUCCESS;
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}
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