feat: support initializer

.gitignore

@@ -17,3 +17,4 @@ tmp*
 
 # for debug
 test
+.gdb_history

.vscode/settings.json

@@ -1,8 +1,13 @@
 {
   "files.associations": {
     "*.v": "coq",
+    "*.asm": "gas",
+    "*.ts": "typescript",
+    "*.pl": "prolog",
+    "*.plt": "prolog",
     "stdbool.h": "c",
-    "tests": "cpp"
+    "tests": "cpp",
+    "initializer_list": "c"
   },
   "C_Cpp.default.configurationProvider": "ms-vscode.makefile-tools"
 }

ccc.h

@@ -1,13 +1,15 @@
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
+#include <limits.h>
 #include <stdarg.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 typedef struct Type Type;
 typedef struct Member Member;
+typedef struct Initializer Initializer;
 //
 // tokenize.c
 //
@@ -33,6 +35,7 @@ struct Token {
 void error(char *fmt, ...);
 void error_at(char *loc, char *fmt, ...);
 void error_tok(Token *tok, char *fmt, ...);
+void warn_tok(Token *tok, char *fmt, ...);
 Token *peek(char *s);
 Token *consume(char *op);
 char *strndup(char *p, int len);
@@ -59,8 +62,7 @@ struct Var {
   // local variable
   int offset;  // Offset from RBP
   // global variable
-  char *contents;
-  int cont_len;
+  Initializer *initializer;
 };
 typedef struct VarList VarList;
 struct VarList {
@@ -158,11 +160,27 @@ struct Node {
   Member *member;
 };
 
+// global variable initializer
+// global variable can be initialized either by a constant expression or a
+// pointer to another global variable
+struct Initializer {
+  Initializer *next;
+
+  // constant expression
+  int sz;
+  long val;
+
+  // reference to another global variable
+  char *label;
+  long addend;
+};
+
 typedef struct Function Function;
 struct Function {
   Function *next;
   char *name;
   VarList *params;
+  bool is_static;
   Node *node;
   VarList *locals;
   int stack_size;

codegen.c

@@ -554,20 +554,30 @@ void emit_data(Program *prog) {
   for (VarList *vl = prog->globals; vl; vl = vl->next) {
     Var *var = vl->var;
     printf("%s:\n", var->name);
-    if (!var->contents) {
+    if (!var->initializer) {
       printf("  .zero %d\n", size_of(var->ty, var->tok));
       continue;
     }
-    for (int i = 0; i < var->cont_len; i++) {
-      printf("  .byte %d\n", var->contents[i]);
+    for (Initializer *init = var->initializer; init; init = init->next) {
+      if (init->label) {
+        printf("  .quad %s%+ld\n", init->label, init->addend);
+        continue;
+      }
+      if (init->sz == 1) {
+        printf("  .byte %ld\n", init->val);
+      } else {
+        printf("  .%dbyte %ld\n", init->sz, init->val);
+      }
     }
   }
 }
 
 void emit_text(Program *prog) {
   printf(".text\n");
   for (Function *fn = prog->fns; fn; fn = fn->next) {
-    printf(".global %s\n", fn->name);
+    if (!fn->is_static) {
+      printf(".global %s\n", fn->name);
+    }
     printf("%s:\n", fn->name);
     funcname = fn->name;