feat: add continue

.gdb_history

@@ -0,0 +1,10 @@
+run test
+b main
+run test
+n
+b gen
+run test
+c
+n
+s
+q

ccc.h

@@ -86,6 +86,7 @@ typedef enum {
   ND_FOR,        // "for"
   ND_BLOCK,      // { ... }
   ND_BREAK,      // "break"
+  ND_CONTINUE,   // "continue"
   ND_FUNCALL,    // Function call
   ND_EXPR_STMT,  // Expression statement
   ND_STMT_EXPR,  // statement expression

codegen.c

@@ -7,6 +7,7 @@ char *argreg8[] = {"rdi", "rsi", "rdx", "rcx", "r8", "r9"};
 
 int labelseq;
 int brkseq;
+int contseq;
 char *funcname;
 
 void truncate(Type *ty) {
@@ -218,26 +219,31 @@ void gen(Node *node) {
     case ND_WHILE: {
       int seq = labelseq++;
       int brk = brkseq;
-      brkseq = seq;
+      int cont = contseq;
+      brkseq = contseq = seq;
 
-      printf(".Lbegin%d:\n", seq);
+      printf(".L.continue.%d:\n", seq);
       gen(node->cond);
       printf("  pop rax\n");
       printf("  cmp rax, 0\n");
       printf("  je  .L.break.%d\n", seq);
       gen(node->then);
-      printf("  jmp .Lbegin%d\n", seq);
+      printf("  jmp .L.continue.%d\n", seq);
       printf(".L.break.%d:\n", seq);
 
       brkseq = brk;
+      contseq = cont;
       return;
     }
     case ND_FOR: {
       int seq = labelseq++;
       int brk = brkseq;
-      brkseq = seq;
+      int cont = contseq;
+      brkseq = contseq = seq;
 
-      if (node->init) gen(node->init);
+      if (node->init) {
+        gen(node->init);
+      }
       printf(".Lbegin%d:\n", seq);
       if (node->cond) {
         gen(node->cond);
@@ -246,11 +252,15 @@ void gen(Node *node) {
         printf("  je  .L.break.%d\n", seq);
       }
       gen(node->then);
-      if (node->inc) gen(node->inc);
+      printf(".L.continue.%d:\n", seq);
+      if (node->inc) {
+        gen(node->inc);
+      }
       printf("  jmp .Lbegin%d\n", seq);
       printf(".L.break.%d:\n", seq);
 
       brkseq = brk;
+      contseq = cont;
       return;
     }
     case ND_BLOCK:
@@ -263,6 +273,12 @@ void gen(Node *node) {
       }
       printf("  jmp .L.break.%d\n", brkseq);
       return;
+    case ND_CONTINUE:
+      if (contseq == 0) {
+        error_tok(node->tok, "stray continue");
+      }
+      printf("  jmp .L.continue.%d\n", contseq);
+      return;
     case ND_FUNCALL: {
       int nargs = 0;
       for (Node *arg = node->args; arg; arg = arg->next) {

parse.c

@@ -642,6 +642,7 @@ bool is_typename() {
 //      | "for" "(" (expr? ";" | declaration) expr? ";" expr? ")" stmt
 //      | "{" stmt* "}"
 //      | "break" ";"
+//      | "continue" ";"
 //      | declaration
 //      | expr ";"
 Node *stmt() {
@@ -714,6 +715,10 @@ Node *stmt() {
     expect(";");
     return new_node(ND_BREAK, tok);
   }
+  if (tok = consume("continue")) {
+    expect(";");
+    return new_node(ND_CONTINUE, tok);
+  }
   if (is_typename()) {
     return declaration();
   }

tests

@@ -786,6 +786,13 @@ int main() {
   assert(3, ({ int i=0; for(;i<10;i++) { for (;;) break; if (i == 3) break; } i; }), "int i=0; for(;i<10;i++) { if (i == 3) break; } i;");
   assert(4, ({ int i=0; while (1) { while(1) break; if (i++ == 3) break; } i; }), "int i=0; while { if (i == 3) break; } i;");
 
+  assert(10, ({ int i=0; int j=0; for (;i<10;i++) { if (i>5) continue; j++; } i; }), "int i=0; int j=0; for (;i<10;i++) { if (i>5) continue; j++; } i;");
+  assert(6, ({ int i=0; int j=0; for (;i<10;i++) { if (i>5) continue; j++; } j; }), "int i=0; int j=0; for (;i<10;i++) { if (i>5) continue; j++; } j;");
+  assert(10, ({ int i=0; int j=0; for(;!i;) { for (;j!=10;j++) continue; break; } j; }), "int i=0; int j=0; for(;!i;) { for (;j!=10;j++) continue; break; } j;");
+  assert(11, ({ int i=0; int j=0; while (i++<10) { if (i>5) continue; j++; } i; }), "int i=0; int j=0; while (i++<10) { if (i>5) continue; j++; } i;");
+  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;");
+
   printf("OK\n");
   return 0;
 }

tokenize.c

@@ -149,9 +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"};
+  static char *kw[] = {"return", "if",    "else",    "while",  "for",
+                       "char",   "int",   "sizeof",  "struct", "typedef",
+                       "short",  "long",  "void",    "_Bool",  "enum",
+                       "static", "break", "continue"};
   for (int i = 0; i < sizeof(kw) / sizeof(*kw); i++) {
     int len = strlen(kw[i]);
     if (startswith(p, kw[i]) && !is_alnum(p[len])) {