/* The University of Illinois/NCSA Open Source License (NCSA) Copyright (c) 2020, Advanced Micro Devices, Inc. All rights reserved. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal with the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimers. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimers in the documentation and/or other materials provided with the distribution. - Neither the names of Advanced Micro Devices, Inc, nor the names of its contributors may be used to endorse or promote products derived from this Software without specific prior written permission. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE SOFTWARE. */ #include "code_object.h" #include "debug.h" #include "logging.h" #include #include #include #include #include #include #include #include #include #if HAVE_MEMFD_CREATE #include #include #endif /* HAVE_MEMFD_CREATE */ #include #include #include #include #include #include #include #include #include #include #include #include namespace amd::debug_agent { code_object_t::code_object_t (amd_dbgapi_code_object_id_t code_object_id) : m_code_object_id (code_object_id) { if (amd_dbgapi_code_object_get_info ( code_object_id, AMD_DBGAPI_CODE_OBJECT_INFO_LOAD_ADDRESS, sizeof (m_load_address), &m_load_address) != AMD_DBGAPI_STATUS_SUCCESS) { agent_warning ("could not get the code object's load address"); return; } char *value; if (amd_dbgapi_code_object_get_info (m_code_object_id, AMD_DBGAPI_CODE_OBJECT_INFO_URI_NAME, sizeof (value), &value) != AMD_DBGAPI_STATUS_SUCCESS) { agent_warning ("could not get the code object's URI"); return; } m_uri.assign (value); free (value); } code_object_t::code_object_t (code_object_t &&rhs) : m_load_address (rhs.m_load_address), m_mem_size (rhs.m_mem_size), m_uri (std::move (rhs.m_uri)), m_code_object_id (rhs.m_code_object_id) { m_fd = rhs.m_fd; rhs.m_fd.reset (); } code_object_t::~code_object_t () { if (m_fd) ::close (*m_fd); } std::optional code_object_t::find_symbol (amd_dbgapi_global_address_t address) { /* Load the symbol table. */ load_symbol_map (); if (auto it = m_symbol_map->upper_bound (address); it != m_symbol_map->begin ()) { if (auto &&[symbol_value, symbol] = *std::prev (it); address < (symbol_value + symbol.second)) { std::string symbol_name = symbol.first; if (int status; auto *demangled_name = abi::__cxa_demangle ( symbol_name.c_str (), nullptr, nullptr, &status)) { symbol_name = demangled_name; free (demangled_name); } return symbol_info_t{ std::move (symbol_name), symbol_value, symbol.second }; } } return {}; } bool code_object_t::open () { agent_assert (!is_open () && "code object is already opened"); const std::string protocol_delim{ "://" }; size_t protocol_end = m_uri.find (protocol_delim); std::string protocol = m_uri.substr (0, protocol_end); protocol_end += protocol_delim.length (); std::transform (protocol.begin (), protocol.end (), protocol.begin (), [] (unsigned char c) { return std::tolower (c); }); std::string path; size_t path_end = m_uri.find_first_of ("#?", protocol_end); if (path_end != std::string::npos) path = m_uri.substr (protocol_end, path_end++ - protocol_end); else path = m_uri.substr (protocol_end); /* %-decode the string. */ std::string decoded_path; decoded_path.reserve (path.length ()); for (size_t i = 0; i < path.length (); ++i) if (path[i] == '%' && std::isxdigit (path[i + 1]) && std::isxdigit (path[i + 2])) { decoded_path += std::stoi (path.substr (i + 1, 2), 0, 16); i += 2; } else decoded_path += path[i]; /* Tokenize the query/fragment. */ std::vector tokens; size_t pos, last = path_end; while ((pos = m_uri.find ('&', last)) != std::string::npos) { tokens.emplace_back (m_uri.substr (last, pos - last)); last = pos + 1; } if (last != std::string::npos) tokens.emplace_back (m_uri.substr (last)); /* Create a tag-value map from the tokenized query/fragment. */ std::unordered_map params; std::for_each (tokens.begin (), tokens.end (), [&] (std::string &token) { size_t delim = token.find ('='); if (delim != std::string::npos) params.emplace (token.substr (0, delim), token.substr (delim + 1)); }); std::vector buffer; try { size_t offset{ 0 }, size{ 0 }; if (auto offset_it = params.find ("offset"); offset_it != params.end ()) offset = std::stoul (offset_it->second, nullptr, 0); if (auto size_it = params.find ("size"); size_it != params.end ()) if (!(size = std::stoul (size_it->second, nullptr, 0))) return false; if (protocol == "file") { std::ifstream file (decoded_path, std::ios::in | std::ios::binary); if (!file) { agent_warning ("could not open `%s'", decoded_path.c_str ()); return false; } if (!size) { file.ignore (std::numeric_limits::max ()); size_t bytes = file.gcount (); file.clear (); if (bytes < offset) { agent_warning ("invalid uri `%s' (file size < offset)", decoded_path.c_str ()); return false; } size = bytes - offset; } file.seekg (offset, std::ios_base::beg); buffer.resize (size); file.read (&buffer[0], size); } else if (protocol == "memory") { if (!offset || !size) { agent_warning ("invalid uri `%s' (offset and size must be != 0", m_uri.c_str ()); return false; } amd_dbgapi_process_id_t process_id; if (amd_dbgapi_code_object_get_info ( m_code_object_id, AMD_DBGAPI_CODE_OBJECT_INFO_PROCESS, sizeof (process_id), &process_id) != AMD_DBGAPI_STATUS_SUCCESS) agent_error ("could not get the process from the agent"); buffer.resize (size); if (amd_dbgapi_read_memory (process_id, AMD_DBGAPI_WAVE_NONE, AMD_DBGAPI_LANE_NONE, AMD_DBGAPI_ADDRESS_SPACE_GLOBAL, offset, &size, buffer.data ()) != AMD_DBGAPI_STATUS_SUCCESS) { agent_warning ("could not read memory at 0x%lx", offset); return false; } } else { agent_warning ("\"%s\" protocol not supported", protocol.c_str ()); return false; } } catch (...) { } int fd = #if HAVE_MEMFD_CREATE ::memfd_create ( [uri = m_uri] () -> std::string { /* The memfd_create(2) NAME parameter needs to be at most 249 bytes (excluding the terminating null byte). This is because an entry named "memfd:NAME" will be created in /proc/PID/fd. This entry's name must to be under NAME_MAX bytes limit (255 on Linux), including the "memfd:" prefix. The name parameter given to memfd_create is not important, and do not need to be unique. However, to help debugging, trim the extra bytes from the left, so the "offset" and "size" parts encoded in the name are kept. */ if (auto length = uri.length (); length > NAME_MAX - 6 /* strlen ("memfd:") */) { /* Since we know that a code object's URI must start with 'memory://' or 'file://', and that 'memory://' code objects can't exceed the 249 limit, we must have a 'file://' URI. When left-trimming, keep the 'file://' part. */ agent_assert (uri.substr (0, 7) == "file://"); return uri.substr (0, 7) /* Keep the "file://" prefix (8b) */ + "[...]" + uri.substr (length - (NAME_MAX - 6 /* strlen ("memfd:") */ - 8 /* strlen ("file://") */ - 5 /* strlen ("[...]") */), length); } return uri; }().c_str (), MFD_ALLOW_SEALING | MFD_CLOEXEC); #else /* !HAVE_MEMFD_CREATE */ ::open ("/tmp", O_TMPFILE | O_RDWR, 0666); #endif /* !HAVE_MEMFD_CREATE */ if (fd == -1) { agent_warning ("could not create a temporary file for code object: %s", strerror (errno)); return false; } if (size_t size = ::write (fd, buffer.data (), buffer.size ()); size != buffer.size ()) { agent_warning ("could not write to the temporary file"); return false; } ::lseek (fd, 0, SEEK_SET); /* Calculate the size of the code object as loaded in memory. Its size is the distance of the end of the highest segment from the load address. */ if (elf_version (EV_CURRENT) == EV_NONE) { agent_warning ("elf_version failed"); return false; } std::unique_ptr elf ( elf_begin (fd, ELF_C_READ, nullptr), [] (Elf *elf) { elf_end (elf); }); if (!elf) { agent_warning ("elf_begin failed for `%s'", m_uri.c_str ()); return false; } size_t phnum; if (elf_getphdrnum (elf.get (), &phnum) != 0) { agent_warning ("elf_getphdrnum failed for `%s'", m_uri.c_str ()); return false; } for (size_t i = 0; i < phnum; ++i) { GElf_Phdr phdr_mem; GElf_Phdr *phdr = gelf_getphdr (elf.get (), i, &phdr_mem); if (!phdr) { agent_warning ("gelf_getphdr failed for `%s'", m_uri.c_str ()); return false; } if (phdr->p_type == PT_LOAD) m_mem_size = std::max (m_mem_size, phdr->p_vaddr + phdr->p_memsz); } m_fd.emplace (fd); return true; } namespace { std::optional>> get_source_file_index (const std::string &file_name) { static std::unordered_map> file_map; if (auto it = file_map.find (file_name); it != file_map.end ()) return it->second; std::ifstream file (file_name); if (!file) return std::nullopt; auto [it, success] = file_map.emplace (file_name, std::vector{}); agent_assert (success && "emplace should have succeeded"); auto &lines = it->second; std::string line; while (std::getline (file, line)) lines.emplace_back (line); return lines; } } /* namespace */ void code_object_t::load_symbol_map () { agent_assert (is_open () && "code object is not opened"); if (m_symbol_map.has_value ()) return; m_symbol_map.emplace (); std::unique_ptr elf ( elf_begin (*m_fd, ELF_C_READ, nullptr), [] (Elf *elf) { elf_end (elf); }); if (!elf) return; /* Slurp the symbol table. */ Elf_Scn *scn = nullptr; while ((scn = elf_nextscn (elf.get (), scn)) != nullptr) { GElf_Shdr shdr_mem; GElf_Shdr *shdr = gelf_getshdr (scn, &shdr_mem); if (shdr->sh_type != SHT_SYMTAB && shdr->sh_type != SHT_DYNSYM) continue; Elf_Data *data = elf_getdata (scn, nullptr); if (!data) continue; size_t symbol_count = data->d_size / gelf_fsize (elf.get (), ELF_T_SYM, 1, EV_CURRENT); for (size_t j = 0; j < symbol_count; ++j) { GElf_Sym sym_mem; GElf_Sym *sym = gelf_getsym (data, j, &sym_mem); if (GELF_ST_TYPE (sym->st_info) != STT_FUNC || sym->st_shndx == SHN_UNDEF) continue; std::string symbol_name{ elf_strptr (elf.get (), shdr->sh_link, sym->st_name) }; auto [it, success] = m_symbol_map->emplace ( m_load_address + sym->st_value, std::make_pair (symbol_name, sym->st_size)); /* If there already was a symbol defined at this address, but this new symbol covers a larger address range, replace the old symbol with this new one. */ if (!success && sym->st_size > it->second.second) it->second = std::make_pair (symbol_name, sym->st_size); } } /* TODO: If we did not see a symbtab, check the dynamic segment. */ } void code_object_t::load_debug_info () { agent_assert (is_open () && "code object is not opened"); if (m_line_number_map.has_value () && m_pc_ranges_map.has_value ()) return; m_line_number_map.emplace (); m_pc_ranges_map.emplace (); std::unique_ptr dbg ( dwarf_begin (*m_fd, DWARF_C_READ), [] (Dwarf *dbg) { dwarf_end (dbg); }); if (!dbg) return; Dwarf_Off cu_offset{ 0 }, next_offset; size_t header_size; while (!dwarf_nextcu (dbg.get (), cu_offset, &next_offset, &header_size, nullptr, nullptr, nullptr)) { Dwarf_Die die; if (!dwarf_offdie (dbg.get (), cu_offset + header_size, &die)) continue; ptrdiff_t offset = 0; Dwarf_Addr base, start{ 0 }, end{ 0 }; /* dwarf_ranges returns a single contiguous range (DW_AT_low_pc/DW_AT_high_pc), or a series of non-contiguous ranges (DW_AT_ranges). */ while ((offset = dwarf_ranges (&die, offset, &base, &start, &end) > 0)) m_pc_ranges_map->emplace (m_load_address + start, m_load_address + end); Dwarf_Lines *lines; size_t line_count; if (dwarf_getsrclines (&die, &lines, &line_count)) continue; for (size_t i = 0; i < line_count; ++i) { Dwarf_Addr addr; int line_number; if (Dwarf_Line *line = dwarf_onesrcline (lines, i); line && !dwarf_lineaddr (line, &addr) && !dwarf_lineno (line, &line_number) && line_number) { m_line_number_map->emplace ( m_load_address + addr, std::make_pair (dwarf_linesrc (line, nullptr, nullptr), line_number)); } } cu_offset = next_offset; } } void code_object_t::disassemble (amd_dbgapi_architecture_id_t architecture_id, amd_dbgapi_global_address_t pc) { amd_dbgapi_process_id_t process_id; if (amd_dbgapi_code_object_get_info (m_code_object_id, AMD_DBGAPI_CODE_OBJECT_INFO_PROCESS, sizeof (process_id), &process_id) != AMD_DBGAPI_STATUS_SUCCESS) agent_error ("could not get the process from the agent"); amd_dbgapi_size_t largest_instruction_size; if (amd_dbgapi_architecture_get_info ( architecture_id, AMD_DBGAPI_ARCHITECTURE_INFO_LARGEST_INSTRUCTION_SIZE, sizeof (largest_instruction_size), &largest_instruction_size) != AMD_DBGAPI_STATUS_SUCCESS) agent_error ("could not get the instruction size from the architecture"); /* Load the line number table, and low/high pc for all CUs. */ load_debug_info (); constexpr int context_byte_size = 24; amd_dbgapi_global_address_t start_pc; /* Try to find a line number that precedes `pc` by `context_byte_size` bytes. If we don't have a line number map, simply start the disassembly from the current pc. */ if (auto it = m_line_number_map->upper_bound (pc); it != m_line_number_map->begin ()) { do { it = std::prev (it); if ((pc - it->first) >= context_byte_size) break; } while (it != m_line_number_map->begin ()); start_pc = it->first; } else { /* Don't print any instructions before the current pc. The instructions are of variable size so we can't reliably tell if we'll land on a valid instruction. */ start_pc = pc; } amd_dbgapi_global_address_t end_pc = pc + context_byte_size; /* If pc is included in a [lowpc,highpc] interval, clamp start_pc and end_pc. */ if (auto it = m_pc_ranges_map->upper_bound (pc); it != m_pc_ranges_map->begin ()) { if (auto [low_pc, high_pc] = *std::prev (it); pc < high_pc) { start_pc = std::max (start_pc, low_pc); end_pc = std::min (end_pc, high_pc); } } auto symbol = find_symbol (pc); agent_out << std::endl << "Disassembly"; if (symbol) agent_out << " for function " << symbol->m_name; agent_out << ":" << std::endl; agent_out << " code object: " << m_uri << std::endl; agent_out << " loaded at: " << "[0x" << std::hex << m_load_address << "-" << "0x" << std::hex << (m_load_address + m_mem_size) << "]" << std::endl; /* Remember the start_pc address to print the first source line. */ amd_dbgapi_global_address_t saved_start_pc{ start_pc }; /* Now that we know start_pc is a valid instruction address, skip ahead until the distance between start_pc and pc is <= context_byte_size. */ while ((pc - start_pc) > context_byte_size) { std::vector buffer (largest_instruction_size); amd_dbgapi_size_t size = buffer.size (); if (amd_dbgapi_read_memory ( process_id, AMD_DBGAPI_WAVE_NONE, AMD_DBGAPI_LANE_NONE, AMD_DBGAPI_ADDRESS_SPACE_GLOBAL, start_pc, &size, buffer.data ()) != AMD_DBGAPI_STATUS_SUCCESS) break; if (amd_dbgapi_disassemble_instruction ( architecture_id, start_pc, &size, buffer.data (), nullptr, amd_dbgapi_symbolizer_id_t{}, nullptr) != AMD_DBGAPI_STATUS_SUCCESS) break; if ((pc - (start_pc + size)) < context_byte_size) break; start_pc += size; } std::string prev_file_name; size_t prev_line_number{ 0 }; amd_dbgapi_global_address_t addr{ start_pc }; while (addr < end_pc) { if (auto it = m_line_number_map->find (addr == start_pc ? saved_start_pc : addr); it != m_line_number_map->end ()) { const std::string &file_name = it->second.first; size_t line_number = it->second.second; if (file_name != prev_file_name || line_number != prev_line_number) agent_out << std::endl; if (file_name != prev_file_name) agent_out << file_name << ":" << std::endl; /* If the source line for `addr` is a different line than the previous one printed, then print it. If the previous line printed is in the same file and an earlier line, and if all the lines between it and the source line for `addr` have no associated instructions (indicated by their being no entries in the line number map that mention them), then display those lines as well as a source line block. That allows the disassembly to show all the source file lines, including those that have no associated code. */ if (file_name != prev_file_name || line_number != prev_line_number) { size_t first_line = line_number; size_t last_line = line_number; /* Find the first line to print between prev_line_number and line_number that does not appear in the line number table. */ if (file_name == prev_file_name && (line_number + 1) > prev_line_number) { while (--first_line > prev_line_number) { if (std::find_if ( m_line_number_map->begin (), m_line_number_map->end (), [first_line, &file_name] ( const std::remove_reference_t::value_type &value) { return file_name == value.second.first && first_line == value.second.second; }) != m_line_number_map->end ()) break; } /* First is either prev_line_number, or a line associated with another address, so start at the next line. */ ++first_line; } for (size_t line = first_line; line <= last_line; ++line) { agent_out << std::setfill (' ') << std::setw (8) << std::left << std::dec << line; if (auto lines = get_source_file_index (file_name); !lines) agent_out << file_name << ": No such file or directory."; else if (line && line <= lines->get ().size ()) agent_out << lines->get ()[line - 1]; agent_out << std::endl; } } prev_file_name = file_name; prev_line_number = line_number; /* If the start_pc address is not the begining of a line number block, then print ... to show that the following instruction is not the first in the block. */ if (addr == start_pc && start_pc != saved_start_pc) agent_out << " ..." << std::endl; } std::vector buffer (largest_instruction_size); amd_dbgapi_size_t size = buffer.size (); if (amd_dbgapi_read_memory ( process_id, AMD_DBGAPI_WAVE_NONE, AMD_DBGAPI_LANE_NONE, AMD_DBGAPI_ADDRESS_SPACE_GLOBAL, addr, &size, buffer.data ()) != AMD_DBGAPI_STATUS_SUCCESS) { agent_out << "Cannot access memory at address 0x" << std::hex << addr << std::endl; break; } auto symbolizer = [] (amd_dbgapi_symbolizer_id_t symbolizer_id, amd_dbgapi_global_address_t address, char **symbol_text) { auto &code_object = *reinterpret_cast (symbolizer_id); std::stringstream ss; ss << "0x" << std::hex << address; if (auto &&symbol = code_object.find_symbol (address)) { ss << " <" << symbol->m_name; ss << "+" << std::dec << (address - symbol->m_value); ss << ">"; } *symbol_text = strdup (ss.str ().c_str ()); return AMD_DBGAPI_STATUS_SUCCESS; }; char *value; if (amd_dbgapi_disassemble_instruction ( architecture_id, addr, &size, buffer.data (), &value, reinterpret_cast (this), symbolizer) != AMD_DBGAPI_STATUS_SUCCESS) agent_error ("amd_dbgapi_disassemble_instruction failed"); std::string instruction (value); free (value); agent_out << ((addr == pc) ? " => " : " "); agent_out << "0x" << std::hex << addr; if (symbol) { agent_out << " <"; if (addr >= symbol->m_value) agent_out << "+" << std::dec << (addr - symbol->m_value); else agent_out << "-" << std::dec << (symbol->m_value - addr); agent_out << ">"; } agent_out << ": " << instruction << std::endl; addr += size; } /* If the end_pc address (addr) is not the begining of a new line number block, then print ... to show that the previous instruction was not the last of the instructions associated with the previous source ine printed. */ if (auto it = m_line_number_map->find (addr); it == m_line_number_map->end ()) agent_out << " ..." << std::endl; agent_out << std::endl << "End of disassembly." << std::endl; } bool code_object_t::save (const std::string &directory) const { agent_assert (is_open () && "code object is not opened"); std::string name{ std::to_string (m_code_object_id.handle) + "_" + m_uri }; size_t pos{}; while ((pos = name.find_first_of (":/#?&="), pos) != std::string::npos) name[pos] = '_'; std::string file_path = directory + '/' + name; std::ofstream file (file_path, std::ios::out | std::ios::binary); std::vector buffer (lseek (*m_fd, 0, SEEK_END)); ::lseek (*m_fd, 0, SEEK_SET); if (size_t size = ::read (*m_fd, buffer.data (), buffer.size ()); size != buffer.size ()) return false; file.write (buffer.data (), buffer.size ()); file.close (); return file.good (); } } /* namespace amd::debug_agent */