1 files changed, 362 insertions, 0 deletions
diff --git a/linux/bootstrap/038literal_strings.cc b/linux/bootstrap/038literal_strings.cc
new file mode 100644
index 00000000..b0b3c13f
--- /dev/null
+++ b/linux/bootstrap/038literal_strings.cc
@@ -0,0 +1,362 @@
+//: Allow instructions to mention literals directly.
+//:
+//: This layer will transparently move them to the global segment (assumed to
+//: always be the second segment).
+
+void test_transform_literal_string() {
+  run(
+      "== code 0x1\n"
+      "b8/copy  \"test\"/imm32\n"
+      "== data 0x2000\n"  // need an empty segment
+  );
+  CHECK_TRACE_CONTENTS(
+      "transform: -- move literal strings to data segment\n"
+      "transform: adding global variable '__subx_global_1' containing \"test\"\n"
+      "transform: line after transform: 'b8 __subx_global_1'\n"
+  );
+}
+
+//: We don't rely on any transforms running in previous layers, but this layer
+//: knows about labels and global variables and will emit them for previous
+//: layers to transform.
+:(after "Begin Transforms")
+Transform.push_back(transform_literal_strings);
+
+:(before "End Globals")
+int Next_auto_global = 1;
+:(before "End Reset")
+Next_auto_global = 1;
+:(code)
+void transform_literal_strings(program& p) {
+  trace(3, "transform") << "-- move literal strings to data segment" << end();
+  if (p.segments.empty()) return;
+  vector<line> new_lines;
+  for (int s = 0;  s < SIZE(p.segments);  ++s) {
+    segment& seg = p.segments.at(s);
+    trace(99, "transform") << "segment '" << seg.name << "'" << end();
+    for (int i = 0;  i < SIZE(seg.lines);  ++i) {
+//?       cerr << seg.name << '/' << i << '\n';
+      line& line = seg.lines.at(i);
+      for (int j = 0;  j < SIZE(line.words);  ++j) {
+        word& curr = line.words.at(j);
+        if (curr.data.at(0) != '"') continue;
+        ostringstream global_name;
+        global_name << "__subx_global_" << Next_auto_global;
+        ++Next_auto_global;
+        add_global_to_data_segment(global_name.str(), curr, new_lines);
+        curr.data = global_name.str();
+      }
+      trace(99, "transform") << "line after transform: '" << data_to_string(line) << "'" << end();
+    }
+  }
+  segment* data = find(p, "data");
+  if (data)
+    data->lines.insert(data->lines.end(), new_lines.begin(), new_lines.end());
+}
+
+void add_global_to_data_segment(const string& name, const word& value, vector<line>& out) {
+  trace(99, "transform") << "adding global variable '" << name << "' containing " << value.data << end();
+  // emit label
+  out.push_back(label(name));
+  // emit size for size-prefixed array
+  out.push_back(line());
+  emit_hex_bytes(out.back(), SIZE(value.data)-/*skip quotes*/2, 4/*bytes*/);
+  // emit data byte by byte
+  out.push_back(line());
+  line& curr = out.back();
+  for (int i = /*skip start quote*/1;  i < SIZE(value.data)-/*skip end quote*/1;  ++i) {
+    char c = value.data.at(i);
+    curr.words.push_back(word());
+    curr.words.back().data = hex_byte_to_string(c);
+    curr.words.back().metadata.push_back(string(1, c));
+  }
+}
+
+//: Within strings, whitespace is significant. So we need to redo our instruction
+//: parsing.
+
+void test_instruction_with_string_literal() {
+  parse_instruction_character_by_character(
+      "a \"abc  def\" z\n"  // two spaces inside string
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: a\n"
+      "parse2: word: \"abc  def\"\n"
+      "parse2: word: z\n"
+  );
+  // no other words
+  CHECK_TRACE_COUNT("parse2", 3);
+}
+
+void test_string_literal_in_data_segment() {
+  run(
+      "== code 0x1\n"
+      "b8/copy  X/imm32\n"
+      "== data 0x2000\n"
+      "X:\n"
+      "\"test\"/imm32\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "transform: -- move literal strings to data segment\n"
+      "transform: adding global variable '__subx_global_1' containing \"test\"\n"
+      "transform: line after transform: '__subx_global_1'\n"
+  );
+}
+
+void test_string_literal_with_missing_quote() {
+  Hide_errors = true;
+  run(
+      "== code 0x1\n"
+      "b8/copy  \"test/imm32\n"
+      "== data 0x2000\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "error: unclosed string in: b8/copy  \"test/imm32"
+  );
+}
+
+:(before "End Line Parsing Special-cases(line_data -> l)")
+if (line_data.find('"') != string::npos) {  // can cause false-positives, but we can handle them
+  parse_instruction_character_by_character(line_data, l);
+  continue;
+}
+
+:(code)
+void parse_instruction_character_by_character(const string& line_data, vector<line>& out) {
+  if (line_data.find('\n') != string::npos  && line_data.find('\n') != line_data.size()-1) {
+    raise << "parse_instruction_character_by_character: should receive only a single line\n" << end();
+    return;
+  }
+  // parse literals
+  istringstream in(line_data);
+  in >> std::noskipws;
+  line result;
+  result.original = line_data;
+  // add tokens (words or strings) one by one
+  while (has_data(in)) {
+    skip_whitespace(in);
+    if (!has_data(in)) break;
+    char c = in.get();
+    if (c == '#') break;  // comment; drop rest of line
+    if (c == ':') break;  // line metadata; skip for now
+    if (c == '.') {
+      if (!has_data(in)) break;  // comment token at end of line
+      if (isspace(in.peek()))
+        continue;  // '.' followed by space is comment token; skip
+    }
+    result.words.push_back(word());
+    if (c == '"') {
+      // string literal; slurp everything between quotes into data
+      ostringstream d;
+      d << c;
+      while (true) {
+        if (!has_data(in)) {
+          raise << "unclosed string in: " << line_data << end();
+          return;
+        }
+        in >> c;
+        if (c == '\\') {
+          in >> c;
+          if (c == 'n') d << '\n';
+          else if (c == '"') d << '"';
+          else if (c == '\\') d << '\\';
+          else {
+            raise << "parse_instruction_character_by_character: unknown escape sequence '\\" << c << "'\n" << end();
+            return;
+          }
+          continue;
+        } else {
+          d << c;
+        }
+        if (c == '"') break;
+      }
+      result.words.back().data = d.str();
+      result.words.back().original = d.str();
+      // slurp metadata
+      ostringstream m;
+      while (!isspace(in.peek()) && has_data(in)) {  // peek can sometimes trigger eof(), so do it first
+        in >> c;
+        if (c == '/') {
+          if (!m.str().empty()) result.words.back().metadata.push_back(m.str());
+          m.str("");
+        }
+        else {
+          m << c;
+        }
+      }
+      if (!m.str().empty()) result.words.back().metadata.push_back(m.str());
+    }
+    else {
+      // not a string literal; slurp all characters until whitespace
+      ostringstream w;
+      w << c;
+      while (!isspace(in.peek()) && has_data(in)) {  // peek can sometimes trigger eof(), so do it first
+        in >> c;
+        w << c;
+      }
+      parse_word(w.str(), result.words.back());
+    }
+    trace(99, "parse2") << "word: " << to_string(result.words.back()) << end();
+  }
+  if (!result.words.empty())
+    out.push_back(result);
+}
+
+void skip_whitespace(istream& in) {
+  while (has_data(in) && isspace(in.peek())) {
+    in.get();
+  }
+}
+
+void skip_comment(istream& in) {
+  if (has_data(in) && in.peek() == '#') {
+    in.get();
+    while (has_data(in) && in.peek() != '\n') in.get();
+  }
+}
+
+line label(string s) {
+  line result;
+  result.words.push_back(word());
+  result.words.back().data = (s+":");
+  return result;
+}
+
+// helper for tests
+void parse_instruction_character_by_character(const string& line_data) {
+  vector<line> out;
+  parse_instruction_character_by_character(line_data, out);
+}
+
+void test_parse2_comment_token_in_middle() {
+  parse_instruction_character_by_character(
+      "a . z\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: a\n"
+      "parse2: word: z\n"
+  );
+  CHECK_TRACE_DOESNT_CONTAIN("parse2: word: .");
+  // no other words
+  CHECK_TRACE_COUNT("parse2", 2);
+}
+
+void test_parse2_word_starting_with_dot() {
+  parse_instruction_character_by_character(
+      "a .b c\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: a\n"
+      "parse2: word: .b\n"
+      "parse2: word: c\n"
+  );
+}
+
+void test_parse2_comment_token_at_start() {
+  parse_instruction_character_by_character(
+      ". a b\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: a\n"
+      "parse2: word: b\n"
+  );
+  CHECK_TRACE_DOESNT_CONTAIN("parse2: word: .");
+}
+
+void test_parse2_comment_token_at_end() {
+  parse_instruction_character_by_character(
+      "a b .\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: a\n"
+      "parse2: word: b\n"
+  );
+  CHECK_TRACE_DOESNT_CONTAIN("parse2: word: .");
+}
+
+void test_parse2_word_starting_with_dot_at_start() {
+  parse_instruction_character_by_character(
+      ".a b c\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: .a\n"
+      "parse2: word: b\n"
+      "parse2: word: c\n"
+  );
+}
+
+void test_parse2_metadata() {
+  parse_instruction_character_by_character(
+      ".a b/c d\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: .a\n"
+      "parse2: word: b /c\n"
+      "parse2: word: d\n"
+  );
+}
+
+void test_parse2_string_with_metadata() {
+  parse_instruction_character_by_character(
+      "a \"bc  def\"/disp32 g\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: a\n"
+      "parse2: word: \"bc  def\" /disp32\n"
+      "parse2: word: g\n"
+  );
+}
+
+void test_parse2_string_with_metadata_at_end() {
+  parse_instruction_character_by_character(
+      "a \"bc  def\"/disp32\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: a\n"
+      "parse2: word: \"bc  def\" /disp32\n"
+  );
+}
+
+void test_parse2_string_with_metadata_at_end_of_line_without_newline() {
+  parse_instruction_character_by_character(
+      "68/push \"test\"/f"  // no newline, which is how calls from parse() will look
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: 68 /push\n"
+      "parse2: word: \"test\" /f\n"
+  );
+}
+
+//: Make sure slashes inside strings don't trigger adding stuff from inside the
+//: string to metadata.
+
+void test_parse2_string_containing_slashes() {
+  parse_instruction_character_by_character(
+      "a \"bc/def\"/disp32\n"
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: \"bc/def\" /disp32\n"
+  );
+}
+
+void test_instruction_with_string_literal_with_escaped_quote() {
+  parse_instruction_character_by_character(
+      "\"a\\\"b\"\n"  // escaped quote inside string
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: \"a\"b\"\n"
+  );
+  // no other words
+  CHECK_TRACE_COUNT("parse2", 1);
+}
+
+void test_instruction_with_string_literal_with_escaped_backslash() {
+  parse_instruction_character_by_character(
+      "\"a\\\\b\"\n"  // escaped backslash inside string
+  );
+  CHECK_TRACE_CONTENTS(
+      "parse2: word: \"a\\b\"\n"
+  );
+  // no other words
+  CHECK_TRACE_COUNT("parse2", 1);
+}