5133 - show instruction source in trace

It's a little hacky in some corner cases. In particular, if debug information
isn't available the trace will contain duplicated lines. This is because
I don't want the core trace lines all my tests rely on (introduced in the
'vm' layer) to have to know about debug info (introduced in the 'labels'
and 'debug' layers).

Thanks Charles Saternos for the feedback and suggestion!

1 files changed, 80 insertions, 3 deletions

diff --git a/subx/039debug.cc b/subx/039debug.cc
index ebf39034..26bb5f7a 100644
--- a/subx/039debug.cc
+++ b/subx/039debug.cc
@@ -6,11 +6,13 @@
 
 :(before "End Globals")
 map</*address*/uint32_t, string> Symbol_name;  // used only by 'subx run'
+map</*address*/uint32_t, string> Source_line;  // used only by 'subx run'
 :(before "End --debug Settings")
-load_map("labels");
+load_labels();
+load_source_lines();
 :(code)
-void load_map(const string& map_filename) {
-  ifstream fin(map_filename.c_str());
+void load_labels() {
+  ifstream fin("labels");
   fin >> std::hex;
   while (has_data(fin)) {
     uint32_t addr = 0;
@@ -21,9 +23,43 @@ void load_map(const string& map_filename) {
   }
 }
 
+void load_source_lines() {
+  ifstream fin("source_lines");
+  fin >> std::hex;
+  while (has_data(fin)) {
+    uint32_t addr = 0;
+    fin >> addr;
+    string line;
+    getline(fin, line);
+    put(Source_line, addr, hacky_squeeze_out_whitespace(line));
+  }
+}
+
 :(after "Run One Instruction")
 if (contains_key(Symbol_name, EIP))
   trace(Callstack_depth, "run") << "== label " << get(Symbol_name, EIP) << end();
+if (contains_key(Source_line, EIP))
+  trace(Callstack_depth, "run") << "0x" << HEXWORD << EIP << ": " << get(Source_line, EIP) << end();
+else
+  // no source line info; do what you can
+  trace(Callstack_depth, "run") << "0x" << HEXWORD << EIP << ": " << debug_info(EIP) << end();
+
+:(code)
+string debug_info(uint32_t inst_address) {
+  uint8_t op = read_mem_u8(EIP);
+  if (op != 0xe8) {
+    ostringstream out;
+    out << HEXBYTE << NUM(op);
+    return out.str();
+  }
+  int32_t offset = read_mem_i32(EIP+/*skip op*/1);
+  uint32_t next_eip = EIP+/*inst length*/5+offset;
+  if (contains_key(Symbol_name, next_eip))
+    return "e8/call "+get(Symbol_name, next_eip);
+  ostringstream out;
+  out << "e8/call 0x" << HEXWORD << next_eip;
+  return out.str();
+}
 
 //: If a label starts with '$watch-', make a note of the effective address
 //: computed by the next instruction. Start dumping out its contents to the
@@ -54,3 +90,44 @@ if (!Watch_this_effective_address.empty()) {
   dbg << "now watching " << HEXWORD << addr << " for " << Watch_this_effective_address << end();
   put(Watch_points, Watch_this_effective_address, addr);
 }
+
+//: helpers
+
+:(code)
+string hacky_squeeze_out_whitespace(const string& s) {
+  // strip whitespace at start
+  string::const_iterator first = s.begin();
+  while (first != s.end() && isspace(*first))
+    ++first;
+  if (first == s.end()) return "";
+
+  // strip whitespace at end
+  string::const_iterator last = --s.end();
+  while (last != s.begin() && isspace(*last))
+    --last;
+  ++last;
+
+  // replace runs of spaces/dots with single space until comment or string
+  // TODO:
+  //   leave alone dots not surrounded by whitespace
+  //   leave alone '#' within word
+  //   leave alone '"' within word
+  //   squeeze spaces after end of string
+  ostringstream out;
+  bool previous_was_space = false;
+  bool in_comment_or_string = false;
+  for (string::const_iterator curr = first;  curr != last;  ++curr) {
+    if (in_comment_or_string)
+      out << *curr;
+    else if (isspace(*curr) || *curr == '.')
+      previous_was_space = true;
+    else {
+      if (previous_was_space)
+        out << ' ';
+      out << *curr;
+      previous_was_space = false;
+      if (*curr == '#' || *curr == '"') in_comment_or_string = true;
+    }
+  }
+  return out.str();
+}