feat: impl define function

50cc.h

@@ -80,6 +80,7 @@ struct Node {
   Node *els;
   Node **block;
   char *funcname;
+  Node **args;
   int len;
   int val;
   int offset;
@@ -98,6 +99,7 @@ Node *add();
 Node *mul();
 Node *unary();
 Node *primary();
+Node *variable();
 
 Node *new_node(NodeKind kind, Node *lhs, Node *rhs);
 Node *new_node_num(int val);
@@ -114,4 +116,5 @@ struct LVar {
   int offset;
 };
 
-extern LVar *locals;
+extern LVar *locals[];
+extern int cur_func;

codegen.c

@@ -85,7 +85,6 @@ void gen(Node *node) {
     case ND_BLOCK:
       for (int i = 0; node->block[i]; i++) {
         gen(node->block[i]);
-        printf("  pop rax\n");
       }
       return;
     case ND_FUNC_CALL:
@@ -114,7 +113,17 @@ void gen(Node *node) {
       printf("%s:\n", node->funcname);
       printf("  push rbp\n");
       printf("  mov rbp, rsp\n");
-      printf("  sub rsp, 208\n");
+      for (int i = 0; node->args[i]; i++) {
+        printf("push %s\n", argRegs[i]);
+        argCount++;
+      }
+
+      if (locals[cur_func]) {
+        int offset = locals[cur_func][0].offset;
+        offset -= argCount * 8;
+        printf("  sub rsp, %d\n", offset);
+      }
+
       gen(node->lhs);
       printf("  mov rsp, rbp\n");
       printf("  pop rbp\n");

main.c

@@ -30,15 +30,16 @@ int main(int argc, char **argv) {
     return 1;
   }
 
-  locals = NULL;
   user_input = argv[1];
   token = tokenize();
   program();
 
   printf(".intel_syntax noprefix\n");
   printf(".global main\n");
 
+  cur_func = 0;
   for (int i = 0; code[i]; i++) {
+    cur_func++;
     gen(code[i]);
   }
 

parser.c

@@ -1,7 +1,8 @@
 #include "50cc.h"
 
 Node *code[100];
-LVar *locals;
+LVar *locals[100];
+int cur_func = 0;
 
 Node *new_node(NodeKind kind, Node *lhs, Node *rhs) {
   Node *node = calloc(1, sizeof(Node));
@@ -83,7 +84,7 @@ int expect_number() {
 
 LVar *find_lvar(Token *tok) {
   int i = 0;
-  for (LVar *var = locals; var; var = var->next) {
+  for (LVar *var = locals[cur_func]; var; var = var->next) {
     i++;
     if (var->len == tok->len && !memcmp(tok->str, var->name, var->len))
       return var;
@@ -100,6 +101,7 @@ void program() {
 
 // func = ident "(" ")" stmt
 Node *func() {
+  cur_func++;
   Node *node;
   Token *tok = consume_ident();
   if (tok == NULL) {
@@ -108,9 +110,20 @@ Node *func() {
   node = calloc(1, sizeof(Node));
   node->kind = ND_FUNC_DEF;
   node->funcname = calloc(100, sizeof(char));
+  node->args = calloc(10, sizeof(Node *));
   memcpy(node->funcname, tok->str, tok->len);
   expect("(");
-  expect(")");
+  int i = 0;
+  for (int i = 0; !consume(")"); i++) {
+    Token *tok = consume_ident();
+    if (tok != NULL) {
+      node->args[i] = variable(tok);
+    }
+    if (consume(")")) {
+      break;
+    }
+    expect(",");
+  }
   node->lhs = stmt();
   return node;
 }
@@ -290,28 +303,31 @@ Node *primary() {
       }
       return node;
     }
-    Node *node = calloc(1, sizeof(Node));
-    node->kind = ND_LVAR;
+    return variable(tok);
+  }
+
+  return new_node_num(expect_number());
+}
 
-    LVar *lvar = find_lvar(tok);
+Node *variable(Token *tok) {
+  Node *node = calloc(1, sizeof(Node));
+  node->kind = ND_LVAR;
 
-    if (lvar) {
-      node->offset = lvar->offset;
+  LVar *lvar = find_lvar(tok);
+  if (lvar) {
+    node->offset = lvar->offset;
+  } else {
+    lvar = calloc(1, sizeof(LVar));
+    lvar->next = locals[cur_func];
+    lvar->name = tok->str;
+    lvar->len = tok->len;
+    if (locals[cur_func] == NULL) {
+      lvar->offset = 8;
     } else {
-      lvar = calloc(1, sizeof(LVar));
-      lvar->next = locals;
-      lvar->name = tok->str;
-      lvar->len = tok->len;
-      if (locals == NULL) {
-        lvar->offset = 8;
-      } else {
-        lvar->offset = locals->offset + 8;
-      }
-      node->offset = lvar->offset;
-      locals = lvar;
+      lvar->offset = locals[cur_func]->offset + 8;
     }
-    return node;
+    node->offset = lvar->offset;
+    locals[cur_func] = lvar;
   }
-
-  return new_node_num(expect_number());
-}
+  return node;
+}

test.sh

@@ -21,6 +21,26 @@ assert(){
 }
 
 assert 2 "main () { return 2;}"
+assert 3 "
+main() return func(1, 2);
+func(a, b) { return a + b; }
+"
+
+assert 4 "
+main() return func(1, 2, 3);
+func(a, b, c) { return a + c; }
+"
+
+assert 3 "main() {
+  a = 4;
+  return fib(a);
+}
+fib(n){
+  if(n == 0) return 0;
+  if(n == 1) return 1;
+  return  fib(n - 1)+ fib(n -2);
+}
+"
 # assert 42 "42;"
 # assert 21 "5+20-4;"
 # assert 2 " 5 - 3; "