1 //: Allow instructions to mention literals directly.
  2 //:
  3 //: This layer will transparently move them to the global segment (assumed to
  4 //: always be the second segment).
  5 
  6 :(scenario transform_literal_string)
  7 == code
  8 b8/copy  "test"/imm32
  9 == data  # need to manually create this for now
 10 +transform: -- move literal strings to data segment
 11 +transform: adding global variable '__subx_global_1' containing "test"
 12 +transform: instruction after transform: 'b8 __subx_global_1'
 13 
 14 //: We don't rely on any transforms running in previous layers, but this layer
 15 //: knows about labels and global variables and will emit them for previous
 16 //: layers to transform.
 17 :(after "Begin Transforms")
 18 // Begin Level-3 Transforms
 19 Transform.push_back(transform_literal_strings);
 20 // End Level-3 Transforms
 21 
 22 :(before "End Globals")
 23 int Next_auto_global = 1;
 24 :(code)
 25 void transform_literal_strings(program& p) {
 26   trace(99, "transform") << "-- move literal strings to data segment" << end();
 27   if (p.segments.empty()) return;
 28   segment& code = p.segments.at(0);
 29   segment data;
 30   for (int i = 0;  i < SIZE(code.lines);  ++i) {
 31     line& inst = code.lines.at(i);
 32     for (int j = 0;  j < SIZE(inst.words);  ++j) {
 33       word& curr = inst.words.at(j);
 34       if (curr.data.at(0) != '"') continue;
 35       ostringstream global_name;
 36       global_name << "__subx_global_" << Next_auto_global;
 37       ++Next_auto_global;
 38       add_global_to_data_segment(global_name.str(), curr, data);
 39       curr.data = global_name.str();
 40     }
 41     trace(99, "transform") << "instruction after transform: '" << data_to_string(inst) << "'" << end();
 42   }
 43   if (data.lines.empty()) return;
 44   if (SIZE(p.segments) < 2) {
 45     p.segments.resize(2);
 46     p.segments.at(1).lines.swap(data.lines);
 47   }
 48   vector<line>& existing_data = p.segments.at(1).lines;
 49   existing_data.insert(existing_data.end(), data.lines.begin(), data.lines.end());
 50 }
 51 
 52 void add_global_to_data_segment(const string& name, const word& value, segment& data) {
 53   trace(99, "transform") << "adding global variable '" << name << "' containing " << value.data << end();
 54   // emit label
 55   data.lines.push_back(label(name));
 56   // emit size for size-prefixed array
 57   data.lines.push_back(line());
 58   emit_hex_bytes(data.lines.back(), SIZE(value.data)-/*skip quotes*/2, 4/*bytes*/);
 59   // emit data byte by byte
 60   data.lines.push_back(line());
 61   line& curr = data.lines.back();
 62   for (int i = /*skip start quote*/1;  i < SIZE(value.data)-/*skip end quote*/1;  ++i) {
 63     char c = value.data.at(i);
 64     curr.words.push_back(word());
 65     curr.words.back().data = hex_byte_to_string(c);
 66     curr.words.back().metadata.push_back(string(1, c));
 67   }
 68 }
 69 
 70 line label(string s) {
 71   line result;
 72   result.words.push_back(word());
 73   result.words.back().data = (s+":");
 74   return result;
 75 }
 76 
 77 //: Within strings, whitespace is significant. So we need to redo our instruction
 78 //: parsing.
 79 
 80 :(scenarios parse_instruction_character_by_character)
 81 :(scenario instruction_with_string_literal)
 82 a "abc  def" z  # two spaces inside string
 83 +parse2: word: a
 84 +parse2: word: "abc  def"
 85 +parse2: word: z
 86 # no other words
 87 $parse2: 3
 88 
 89 :(before "End Line Parsing Special-cases(line_data -> l)")
 90 if (line_data.find('"') != string::npos) {  // can cause false-positives, but we can handle them
 91   parse_instruction_character_by_character(line_data, l);
 92   continue;
 93 }
 94 
 95 :(code)
 96 void parse_instruction_character_by_character(const string& line_data, vector<line>& out) {
 97   // parse literals
 98   istringstream in(line_data);
 99   in >> std::noskipws;
100   line result;
101   // add tokens (words or strings) one by one
102   while (has_data(in)) {
103     skip_whitespace(in);
104     if (!has_data(in)) break;
105     char c = in.get();
106     if (c == '#') break;  // comment; drop rest of line
107     if (c == ':') break;  // line metadata; skip for now
108     if (c == '.') {
109       if (!has_data(in)) break;  // comment token at end of line
110       if (isspace(in.peek()))
111         continue;  // '.' followed by space is comment token; skip
112     }
113     ostringstream w;
114     w << c;
115     if (c == '"') {
116       // slurp until '"'
117       while (has_data(in)) {
118         in >> c;
119         w << c;
120         if (c == '"') break;
121       }
122     }
123     // slurp any remaining characters until whitespace
124     while (!isspace(in.peek()) && has_data(in)) {  // peek can sometimes trigger eof(), so do it first
125       in >> c;
126       w << c;
127     }
128     result.words.push_back(word());
129     parse_word(w.str(), result.words.back());
130     trace(99, "parse2") << "word: " << to_string(result.words.back()) << end();
131   }
132   if (!result.words.empty())
133     out.push_back(result);
134 }
135 
136 void skip_whitespace(istream& in) {
137   while (true) {
138     if (has_data(in) && isspace(in.peek())) in.get();
139     else break;
140   }
141 }
142 
143 void skip_comment(istream& in) {
144   if (has_data(in) && in.peek() == '#') {
145     in.get();
146     while (has_data(in) && in.peek() != '\n') in.get();
147   }
148 }
149 
150 // helper for tests
151 void parse_instruction_character_by_character(const string& line_data) {
152   vector<line> out;
153   parse_instruction_character_by_character(line_data, out);
154 }
155 
156 :(scenario parse2_comment_token_in_middle)
157 a . z
158 +parse2: word: a
159 +parse2: word: z
160 -parse2: word: .
161 # no other words
162 $parse2: 2
163 
164 :(scenario parse2_word_starting_with_dot)
165 a .b c
166 +parse2: word: a
167 +parse2: word: .b
168 +parse2: word: c
169 
170 :(scenario parse2_comment_token_at_start)
171 . a b
172 +parse2: word: a
173 +parse2: word: b
174 -parse2: word: .
175 
176 :(scenario parse2_comment_token_at_end)
177 a b .
178 +parse2: word: a
179 +parse2: word: b
180 -parse2: word: .
181 
182 :(scenario parse2_word_starting_with_dot_at_start)
183 .a b c
184 +parse2: word: .a
185 +parse2: word: b
186 +parse2: word: c
187 
188 :(scenario parse2_metadata)
189 .a b/c d
190 +parse2: word: .a
191 +parse2: word: b /c
192 +parse2: word: d
193 
194 :(scenario parse2_string_with_metadata)
195 a "bc  def"/disp32 g
196 +parse2: word: a
197 +parse2: word: "bc  def" /disp32
198 +parse2: word: g
199 
200 :(scenario parse2_string_with_metadata_at_end)
201 a "bc  def"/disp32
202 +parse2: word: a
203 +parse2: word: "bc  def" /disp32
204 
205 :(code)
206 void test_parse2_string_with_metadata_at_end_of_line_without_newline() {
207   parse_instruction_character_by_character(
208       "68/push \"test\"/f"  // no newline, which is how calls from parse() will look
209   );
210   CHECK_TRACE_CONTENTS(
211       "parse2: word: 68 /push^D"
212       "parse2: word: \"test\" /f^D"
213   );
214 }