#include "object_loader.hh" #include #include #include extern "C" void __register_frame(uint8_t *); extern "C" void __deregister_frame(uint8_t *); MemoryManager::~MemoryManager() { deregisterEHFrames(); // Deallocate all of the allocated memory. callbacks.dealloc_memory(code_section.base, code_section.size); callbacks.dealloc_memory(read_section.base, read_section.size); callbacks.dealloc_memory(readwrite_section.base, readwrite_section.size); } void unwinding_setjmp(jmp_buf stack_out, void (*func)(void *), void *userdata) { if (setjmp(stack_out)) { } else { func(userdata); } } [[noreturn]] void unwinding_longjmp(jmp_buf stack_in) { longjmp(stack_in, 42); } struct UnwindPoint { UnwindPoint *prev; jmp_buf stack; std::function *f; std::unique_ptr exception; }; static thread_local UnwindPoint *unwind_state = nullptr; static void unwind_payload(void *_point) { UnwindPoint *point = (UnwindPoint *)_point; (*point->f)(); } void catch_unwind(std::function &&f) { UnwindPoint current; current.prev = unwind_state; current.f = &f; unwind_state = ¤t; unwinding_setjmp(current.stack, unwind_payload, (void *)¤t); if (current.exception) { throw *current.exception; } } void unsafe_unwind(std::exception *exception) { UnwindPoint *state = unwind_state; if (state) { state->exception.reset(exception); unwinding_longjmp(state->stack); } else { abort(); } } uint8_t *MemoryManager::allocateCodeSection(uintptr_t size, unsigned alignment, unsigned section_id, llvm::StringRef section_name) { return allocate_bump(code_section, code_bump_ptr, size, alignment); } uint8_t *MemoryManager::allocateDataSection(uintptr_t size, unsigned alignment, unsigned section_id, llvm::StringRef section_name, bool read_only) { // Allocate from the read-only section or the read-write section, depending // on if this allocation should be read-only or not. uint8_t *ret; if (read_only) { ret = allocate_bump(read_section, read_bump_ptr, size, alignment); } else { ret = allocate_bump(readwrite_section, readwrite_bump_ptr, size, alignment); } if (section_name.equals(llvm::StringRef("__llvm_stackmaps")) || section_name.equals(llvm::StringRef(".llvm_stackmaps"))) { stack_map_ptr = ret; stack_map_size = size; } return ret; } void MemoryManager::reserveAllocationSpace(uintptr_t code_size, uint32_t code_align, uintptr_t read_data_size, uint32_t read_data_align, uintptr_t read_write_data_size, uint32_t read_write_data_align) { auto aligner = [](uintptr_t ptr, size_t align) { if (ptr == 0) { return align; } return (ptr + align - 1) & ~(align - 1); }; uint8_t *code_ptr_out = nullptr; size_t code_size_out = 0; auto code_result = callbacks.alloc_memory(aligner(code_size, 4096), PROTECT_READ_WRITE, &code_ptr_out, &code_size_out); assert(code_result == RESULT_OK); code_section = Section{code_ptr_out, code_size_out}; code_bump_ptr = (uintptr_t)code_ptr_out; code_start_ptr = (uintptr_t)code_ptr_out; this->code_size = code_size; uint8_t *read_ptr_out = nullptr; size_t read_size_out = 0; auto read_result = callbacks.alloc_memory(aligner(read_data_size, 4096), PROTECT_READ_WRITE, &read_ptr_out, &read_size_out); assert(read_result == RESULT_OK); read_section = Section{read_ptr_out, read_size_out}; read_bump_ptr = (uintptr_t)read_ptr_out; uint8_t *readwrite_ptr_out = nullptr; size_t readwrite_size_out = 0; auto readwrite_result = callbacks.alloc_memory( aligner(read_write_data_size, 4096), PROTECT_READ_WRITE, &readwrite_ptr_out, &readwrite_size_out); assert(readwrite_result == RESULT_OK); readwrite_section = Section{readwrite_ptr_out, readwrite_size_out}; readwrite_bump_ptr = (uintptr_t)readwrite_ptr_out; } bool MemoryManager::needsToReserveAllocationSpace() { return true; } void MemoryManager::registerEHFrames(uint8_t *addr, uint64_t LoadAddr, size_t size) { // We don't know yet how to do this on Windows, so we hide this on compilation // so we can compile and pass spectests on unix systems #ifndef _WIN32 eh_frame_ptr = addr; eh_frame_size = size; eh_frames_registered = true; callbacks.visit_fde(addr, size, __register_frame); #endif } void MemoryManager::deregisterEHFrames() { // We don't know yet how to do this on Windows, so we hide this on compilation // so we can compile and pass spectests on unix systems #ifndef _WIN32 if (eh_frames_registered) { callbacks.visit_fde(eh_frame_ptr, eh_frame_size, __deregister_frame); } #endif } bool MemoryManager::finalizeMemory(std::string *ErrMsg) { auto code_result = callbacks.protect_memory(code_section.base, code_section.size, mem_protect_t::PROTECT_READ_EXECUTE); if (code_result != RESULT_OK) { return false; } auto read_result = callbacks.protect_memory( read_section.base, read_section.size, mem_protect_t::PROTECT_READ); if (read_result != RESULT_OK) { return false; } // The readwrite section is already mapped as read-write. return false; } void MemoryManager::notifyObjectLoaded(llvm::RuntimeDyld &RTDyld, const llvm::object::ObjectFile &Obj) {} uint8_t *MemoryManager::allocate_bump(Section §ion, uintptr_t &bump_ptr, size_t size, size_t align) { auto aligner = [](uintptr_t &ptr, size_t align) { ptr = (ptr + align - 1) & ~(align - 1); }; // Align the bump pointer to the requires alignment. aligner(bump_ptr, align); auto ret_ptr = bump_ptr; bump_ptr += size; assert(bump_ptr <= (uintptr_t)section.base + section.size); return (uint8_t *)ret_ptr; } struct SymbolLookup : llvm::JITSymbolResolver { public: SymbolLookup(callbacks_t callbacks) : callbacks(callbacks) {} void lookup(const LookupSet &symbols, OnResolvedFunction OnResolved) { LookupResult result; for (auto symbol : symbols) { result.emplace(symbol, symbol_lookup(symbol)); } OnResolved(result); } llvm::Expected getResponsibilitySet(const LookupSet &Symbols) { const std::set empty; return empty; } private: llvm::JITEvaluatedSymbol symbol_lookup(llvm::StringRef name) { uint64_t addr = callbacks.lookup_vm_symbol(name.data(), name.size()); return llvm::JITEvaluatedSymbol(addr, llvm::JITSymbolFlags::None); } callbacks_t callbacks; }; WasmModule::WasmModule(const uint8_t *object_start, size_t object_size, callbacks_t callbacks) : memory_manager( std::unique_ptr(new MemoryManager(callbacks))) { if (auto created_object_file = llvm::object::ObjectFile::createObjectFile(llvm::MemoryBufferRef( llvm::StringRef((const char *)object_start, object_size), "object"))) { object_file = cantFail(std::move(created_object_file)); SymbolLookup symbol_resolver(callbacks); runtime_dyld = std::unique_ptr( new llvm::RuntimeDyld(*memory_manager, symbol_resolver)); runtime_dyld->setProcessAllSections(true); runtime_dyld->loadObject(*object_file); runtime_dyld->finalizeWithMemoryManagerLocking(); if (runtime_dyld->hasError()) { _init_failed = true; return; } } else { _init_failed = true; } } void *WasmModule::get_func(llvm::StringRef name) const { auto symbol = runtime_dyld->getSymbol(name); return (void *)symbol.getAddress(); } uint8_t *WasmModule::get_stack_map_ptr() const { return memory_manager->get_stack_map_ptr(); } size_t WasmModule::get_stack_map_size() const { return memory_manager->get_stack_map_size(); } uint8_t *WasmModule::get_code_ptr() const { return memory_manager->get_code_ptr(); } size_t WasmModule::get_code_size() const { return memory_manager->get_code_size(); }