https://github.com/akkartik/mu/blob/master/subx/039debug.cc

     1 //:: Some helpers for debugging.
     2
     3 //: Load the 'map' file generated during 'subx --map translate' when running 'subx --map --trace run'.
     4 //: (It'll only affect the trace.)
     5
     6 :(before "End Globals")
     7 map</*address*/uint32_t, string> Symbol_name;  // used only by 'subx run'
     8 :(before "End --map Settings")
     9 load_map("map");
    10 :(code)
    11 void load_map(const string& map_filename) {
    12   ifstream fin(map_filename.c_str());
    13   fin >> std::hex;
    14   while (has_data(fin)) {
    15     uint32_t addr = 0;
    16     fin >> addr;
    17     string name;
    18     fin >> name;
    19     put(Symbol_name, addr, name);
    20   }
    21 }
    22
    23 :(after "Run One Instruction")
    24 if (contains_key(Symbol_name, EIP))
    25   trace(Callstack_depth, "run") << "== label " << get(Symbol_name, EIP) << end();
    26
    27 //: make calls in particular more salient
    28 :(before "End Trace Call Instruction")
    29 // at this point we've skipped past the e8 opcode, but not the offset operand
    30 int32_t offset = read_mem_i32(EIP);
    31 uint32_t next_eip = EIP+offset+4;
    32 if (contains_key(Symbol_name, next_eip))
    33   return "/call "+get(Symbol_name, next_eip);
    34
    35 //: If a label starts with '$watch-', make a note of the effective address
    36 //: computed by the next instruction. Start dumping out its contents to the
    37 //: trace after every subsequent instruction.
    38
    39 :(after "Run One Instruction")
    40 dump_watch_points();
    41 :(before "End Globals")
    42 map<string, uint32_t> Watch_points;
    43 :(before "End Reset")
    44 Watch_points.clear();
    45 :(code)
    46 void dump_watch_points() {
    47   if (Watch_points.empty()) return;
    48   dbg << "watch points:" << end();
    49   for (map<string, uint32_t>::iterator p = Watch_points.begin();  p != Watch_points.end();  ++p)
    50     dbg << "  " << p->first << ": " << HEXWORD << p->second << " -> " << HEXWORD << read_mem_u32(p->second) << end();
    51 }
    52
    53 :(before "End Globals")
    54 string Watch_this_effective_address;
    55 :(after "Run One Instruction")
    56 Watch_this_effective_address = "";
    57 if (contains_key(Symbol_name, EIP) && starts_with(get(Symbol_name, EIP), "$watch-"))
    58   Watch_this_effective_address = get(Symbol_name, EIP);
    59 :(after "Found effective_address(addr)")
    60 if (!Watch_this_effective_address.empty()) {
    61   dbg << "now watching " << HEXWORD << addr << " for " << Watch_this_effective_address << end();
    62   put(Watch_points, Watch_this_effective_address, addr);
    63 }