feat: goto statement

diohabara · Jul 25, 2023 · 58b00d5 · 58b00d5
1 parent d5aa742
commit 58b00d5
Show file tree

Hide file tree

Showing 5 changed files with 36 additions and 5 deletions.
diff --git a/ccc.h b/ccc.h
@@ -87,6 +87,8 @@ typedef enum {
   ND_BLOCK,      // { ... }
   ND_BREAK,      // "break"
   ND_CONTINUE,   // "continue"
+  ND_GOTO,       // "goto"
+  ND_LABEL,      // Labeled statement
   ND_FUNCALL,    // Function call
   ND_EXPR_STMT,  // Expression statement
   ND_STMT_EXPR,  // statement expression
@@ -135,6 +137,8 @@ struct Node {
   // Function call
   char *funcname;
   Node *args;
+  // Goto or labeled statement
+  char *label_name;
   Var *var;  // Used if kind == ND_VAR
   long val;  // Used if kind == ND_NUM
   // Struct member access

diff --git a/codegen.c b/codegen.c
@@ -263,6 +263,13 @@ void gen(Node *node) {
       contseq = cont;
       return;
     }
+    case ND_GOTO:
+      printf("  jmp .L.label.%s.%s\n", funcname, node->label_name);
+      return;
+    case ND_LABEL:
+      printf(".L.label.%s.%s:\n", funcname, node->label_name);
+      gen(node->lhs);
+      return;
     case ND_BLOCK:
     case ND_STMT_EXPR:
       for (Node *n = node->body; n; n = n->next) gen(n);

diff --git a/parse.c b/parse.c
@@ -643,6 +643,8 @@ bool is_typename() {
 //      | "{" stmt* "}"
 //      | "break" ";"
 //      | "continue" ";"
+//      | "goto" ident ";"
+//      | ident ":" stmt
 //      | declaration
 //      | expr ";"
 Node *stmt() {
@@ -719,6 +721,20 @@ Node *stmt() {
     expect(";");
     return new_node(ND_CONTINUE, tok);
   }
+  if (tok = consume("goto")) {
+    Node *node = new_node(ND_GOTO, tok);
+    node->label_name = expect_ident();
+    expect(";");
+    return node;
+  }
+  if (tok = consume_ident()) {
+    if (consume(":")) {
+      Node *node = new_unary(ND_LABEL, stmt(), tok);
+      node->label_name = strndup(tok->str, tok->len);
+      return node;
+    }
+    token = tok;
+  }
   if (is_typename()) {
     return declaration();
   }

diff --git a/tests b/tests
@@ -793,6 +793,10 @@ int main() {
   assert(5, ({ int i=0; int j=0; while (i++<10) { if (i>5) continue; j++; } j; }), "int i=0; int j=0; while (i++<10) { if (i>5) continue; j++; } j;");
   assert(11, ({ int i=0; int j=0; while(!i) { while (j++!=10) continue; break; } j; }), "int i=0; int j=0; while(!i) { while (j++!=10) continue; break; } j;");
 
+  assert(3, ({ int i=0; goto a; a: i++; b: i++; c: i++; i; }), "int i=0; goto a; a: i++; b: i++; c: i++; i;");
+  assert(2, ({ int i=0; goto e; d: i++; e: i++; f: i++; i; }), "int i=0; goto d; d: i++; e: i++; f: i++; i;");
+  assert(1, ({ int i=0; goto i; g: i++; h: i++; i: i++; i; }), "int i=0; goto g; h: i++; i: i++; j: i++; i;");
+
   printf("OK\n");
   return 0;
 }
diff --git a/tokenize.c b/tokenize.c
@@ -149,10 +149,10 @@ bool is_alnum(char c) { return is_alpha(c) || ('0' <= c && c <= '9'); }
 
 char *starts_with_reserved(char *p) {
   // Keyword
-  static char *kw[] = {"return", "if",    "else",    "while",  "for",
-                       "char",   "int",   "sizeof",  "struct", "typedef",
-                       "short",  "long",  "void",    "_Bool",  "enum",
-                       "static", "break", "continue"};
+  static char *kw[] = {"return", "if",    "else",     "while",  "for",
+                       "char",   "int",   "sizeof",   "struct", "typedef",
+                       "short",  "long",  "void",     "_Bool",  "enum",
+                       "static", "break", "continue", "goto"};
   for (int i = 0; i < sizeof(kw) / sizeof(*kw); i++) {
     int len = strlen(kw[i]);
     if (startswith(p, kw[i]) && !is_alnum(p[len])) {
@@ -284,7 +284,7 @@ Token *tokenize() {
       continue;
     }
     // Single-letter punctuator
-    if (strchr("+-*/()<>;={},&[].,!~|^", *p)) {
+    if (strchr("+-*/()<>;={},&[].,!~|^:", *p)) {
       cur = new_token(TK_RESERVED, cur, p++, 1);
       continue;
     }