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| 1 | // | ||
| 2 | // Dis VM | ||
| 3 | // File: vm_exception_handler.cpp | ||
| 4 | // Author: arr | ||
| 5 | // | ||
| 6 | |||
| 7 | #include <cstdint> | ||
| 8 | #include <runtime.h> | ||
| 9 | #include <vm_memory.h> | ||
| 10 | #include <exceptions.h> | ||
| 11 | #include <debug.h> | ||
| 12 | |||
| 13 | using namespace disvm; | ||
| 14 | using namespace disvm::runtime; | ||
| 15 | |||
| 16 | std::tuple<const handler_t *, vm_frame_t *, vm_pc_t> disvm::runtime::find_exception_handler( | ||
| 17 | const vm_stack_t &stack, | ||
| 18 | const vm_module_ref_t &faulting_module, | ||
| 19 | const vm_pc_t faulting_pc, | ||
| 20 | const vm_string_t &exception_id) | ||
| 21 | { | ||
| 22 | auto unwind_depth = uint32_t{ 0 }; | ||
| 23 | auto current_module = &faulting_module; | ||
| 24 | auto current_pc = faulting_pc; | ||
| 25 | auto current_frame = stack.peek_frame(); | ||
| 26 | |||
| 27 | while (current_frame != nullptr) | ||
| 28 | { | ||
| 29 | debug::log_msg(debug::component_trace_t::exception, debug::log_level_t::debug, "begin: handler: %d\n", unwind_depth); | ||
| 30 | |||
| 31 | auto &handler_section = current_module->module->handler_section; | ||
| 32 | |||
| 33 | for (auto &handler : handler_section) | ||
| 34 | { | ||
| 35 | // Outside pc range of this handler | ||
| 36 | if (current_pc < handler.begin_pc || handler.end_pc <= current_pc) | ||
| 37 | continue; | ||
| 38 | |||
| 39 | // Find the appropriate exception case | ||
| 40 | for (const auto &exception : handler.exception_table) | ||
| 41 | { | ||
| 42 | auto exception_name = exception.name.get(); | ||
| 43 | if (exception_id.compare_to(exception_name) == 0) | ||
| 44 | { | ||
| 45 | debug::log_msg(debug::component_trace_t::exception, debug::log_level_t::debug, "end: handler: match: %d\n", unwind_depth); | ||
| 46 | return std::tuple<const handler_t *, vm_frame_t *, std::size_t>{ &handler, current_frame, exception.pc }; | ||
| 47 | } | ||
| 48 | else if (exception_name == nullptr && exception.pc != runtime_constants::invalid_program_counter) | ||
| 49 | { | ||
| 50 | debug::log_msg(debug::component_trace_t::exception, debug::log_level_t::debug, "end: handler: fallback: %d\n", unwind_depth); | ||
| 51 | return std::tuple<const handler_t *, vm_frame_t *, std::size_t>{ &handler, current_frame, exception.pc }; | ||
| 52 | } | ||
| 53 | } | ||
| 54 | } | ||
| 55 | |||
| 56 | // Decrement the frame program counter. See raise instruction for details. | ||
| 57 | current_pc = static_cast<word_t>(current_frame->prev_pc() - 1); | ||
| 58 | |||
| 59 | // Update the current module if it changes walking up the stack. | ||
| 60 | auto prev_mod_ref = current_frame->prev_module_ref(); | ||
| 61 | if (prev_mod_ref != nullptr) | ||
| 62 | current_module = prev_mod_ref; | ||
| 63 | |||
| 64 | // Move up the stack. | ||
| 65 | current_frame = current_frame->prev_frame(); | ||
| 66 | ++unwind_depth; | ||
| 67 | } | ||
| 68 | |||
| 69 | auto faulting_module_name = faulting_module.module->module_name->str(); | ||
| 70 | throw unhandled_user_exception{ exception_id.str(), faulting_module_name, faulting_pc }; | ||
| 71 | } | ||