Add #line

chibicc.h

@@ -59,6 +59,10 @@ typedef struct {
   char *name;
   int file_no;
   char *contents;
+
+  // For #line directive
+  char *display_name;
+  int line_delta;
 } File;
 
 // Token type
@@ -74,7 +78,9 @@ struct Token {
   char *str;        // String literal contents including terminating '\0'
 
   File *file;       // Source location
+  char *filename;   // Filename
   int line_no;      // Line number
+  int line_delta;   // Line number
   bool at_bol;      // True if this token is at beginning of line
   bool has_space;   // True if this token follows a space character
   Hideset *hideset; // For macro expansion

preprocess.c

@@ -705,6 +705,24 @@ static Token *include_file(Token *tok, char *path, Token *filename_tok) {
   return append(tok2, tok);
 }
 
+// Read #line arguments
+static void read_line_marker(Token **rest, Token *tok) {
+  Token *start = tok;
+  tok = preprocess(copy_line(rest, tok));
+
+  if (tok->kind != TK_NUM || tok->ty->kind != TY_INT)
+    error_tok(tok, "invalid line marker");
+  start->file->line_delta = tok->val - start->line_no;
+
+  tok = tok->next;
+  if (tok->kind == TK_EOF)
+    return;
+
+  if (tok->kind != TK_STR)
+    error_tok(tok, "filename expected");
+  start->file->display_name = tok->str;
+}
+
 // Visit all tokens in `tok` while evaluating preprocessing
 // macros and directives.
 static Token *preprocess2(Token *tok) {
@@ -718,6 +736,8 @@ static Token *preprocess2(Token *tok) {
 
     // Pass through if it is not a "#".
     if (!is_hash(tok)) {
+      tok->line_delta = tok->file->line_delta;
+      tok->filename = tok->file->display_name;
       cur = cur->next = tok;
       tok = tok->next;
       continue;
@@ -814,6 +834,11 @@ static Token *preprocess2(Token *tok) {
       continue;
     }
 
+    if (equal(tok, "line")) {
+      read_line_marker(&tok, tok->next);
+      continue;
+    }
+
     if (equal(tok, "error"))
       error_tok(tok, "error");
 
@@ -847,13 +872,14 @@ static Macro *add_builtin(char *name, macro_handler_fn *fn) {
 static Token *file_macro(Token *tmpl) {
   while (tmpl->origin)
     tmpl = tmpl->origin;
-  return new_str_token(tmpl->file->name, tmpl);
+  return new_str_token(tmpl->file->display_name, tmpl);
 }
 
 static Token *line_macro(Token *tmpl) {
   while (tmpl->origin)
     tmpl = tmpl->origin;
-  return new_num_token(tmpl->line_no, tmpl);
+  int i = tmpl->line_no + tmpl->file->line_delta;
+  return new_num_token(i, tmpl);
 }
 
 // __COUNTER__ is expanded to serial values starting from 0.
@@ -1022,5 +1048,8 @@ Token *preprocess(Token *tok) {
     error_tok(cond_incl->tok, "unterminated conditional directive");
   convert_pp_tokens(tok);
   join_adjacent_string_literals(tok);
+
+  for (Token *t = tok; t; t = t->next)
+    t->line_no += t->line_delta;
   return tok;
 }

test/line.c

@@ -0,0 +1,17 @@
+#include "test.h"
+
+int main() {
+#line 500 "foo"
+  ASSERT(501, __LINE__);
+  ASSERT(0, strcmp(__FILE__, "foo"));
+
+#line 800 "bar"
+  ASSERT(801, __LINE__);
+  ASSERT(0, strcmp(__FILE__, "bar"));
+
+#line 1
+  ASSERT(2, __LINE__);
+
+  printf("OK\n");
+  return 0;
+}

tokenize.c

@@ -103,6 +103,7 @@ static Token *new_token(TokenKind kind, char *start, char *end) {
   tok->loc = start;
   tok->len = end - start;
   tok->file = current_file;
+  tok->filename = current_file->display_name;
   tok->at_bol = at_bol;
   tok->has_space = has_space;
 
@@ -674,6 +675,7 @@ File **get_input_files(void) {
 File *new_file(char *name, int file_no, char *contents) {
   File *file = calloc(1, sizeof(File));
   file->name = name;
+  file->display_name = name;
   file->file_no = file_no;
   file->contents = contents;
   return file;