static int ExtractSymbolsFromBinary()

in src/brpc/builtin/pprof_service.cpp [299:400]

• 91 lines of code
• 28 McCabe index (conditional complexity)

static int ExtractSymbolsFromBinary(
    std::map<uintptr_t, std::string>& addr_map,
    const LibInfo& lib_info) {
    butil::Timer tm;
    tm.start();
    std::string cmd = "nm -C -p ";
    cmd.append(lib_info.path);
    std::stringstream ss;
    const int rc = butil::read_command_output(ss, cmd.c_str());
    if (rc < 0) {
        LOG(ERROR) << "Fail to popen `" << cmd << "'";
        return -1;
    }
    std::string line;
    while (std::getline(ss, line)) {
        butil::StringSplitter sp(line.c_str(), ' ');
        if (sp == NULL) {
            continue;
        }
        char* endptr = NULL;
        uintptr_t addr = strtoull(sp.field(), &endptr, 16);
        if (*endptr != ' ') {
            continue;
        }
        if (addr < lib_info.start_addr) {
            addr = addr + lib_info.start_addr - lib_info.offset;
        }
        if (addr >= lib_info.end_addr) {
            continue;
        }
        ++sp;
        if (sp == NULL) {
            continue;
        }
        if (sp.length() != 1UL) {
            continue;
        }
        //const char c = *sp.field();
        
        ++sp;
        if (sp == NULL) {
            continue;
        }
        const char* name_begin = sp.field();
        if (strncmp(name_begin, "typeinfo ", 9) == 0 ||
            strncmp(name_begin, "VTT ", 4) == 0 ||
            strncmp(name_begin, "vtable ", 7) == 0 ||
            strncmp(name_begin, "global ", 7) == 0 ||
            strncmp(name_begin, "guard ", 6) == 0) {
            addr_map[addr] = std::string();
            continue;
        }
        
        const char* name_end = sp.field();
        bool stop = false;
        char last_char = '\0';
        while (1) {
            switch (*name_end) {
            case 0:
            case '\r':
            case '\n':
                stop = true;
                break;
            case '(':
            case '<':
                // \(.*\w\)[(<]...    -> \1
                // foo(..)            -> foo
                // foo<...>(...)      -> foo
                // a::b::foo(...)     -> a::b::foo
                // a::(b)::foo(...)   -> a::(b)::foo
                if (isalpha(last_char) || isdigit(last_char) ||
                    last_char == '_') {
                    stop = true;
                }
            default:
                break;
            }
            if (stop) {
                break;
            }
            last_char = *name_end++;
        }
        // If address conflicts, choose a shorter name (not necessarily to be
        // T type in nm). This works fine because aliases often have more
        // prefixes.
        const size_t name_len = name_end - name_begin;
        SymbolMap::iterator it = addr_map.find(addr);
        if (it != addr_map.end()) {
            if (name_len < it->second.size()) {
                it->second.assign(name_begin, name_len);
            }
        } else {
            addr_map[addr] = std::string(name_begin, name_len);
        }
    }
    if (addr_map.find(lib_info.end_addr) == addr_map.end()) {
        addr_map[lib_info.end_addr] = std::string();
    }
    tm.stop();
    RPC_VLOG << "Loaded " << lib_info.path << " in " << tm.m_elapsed() << "ms";
    return 0;
}