Specify label type in assembler

```
.type main, @function
.type var, @object
```

include/elf.h

@@ -114,6 +114,8 @@ typedef struct {
 #define STB_GLOBAL  (1)
 
 #define STT_NOTYPE   (0)
+#define STT_OBJECT   (1)
+#define STT_FUNC     (2)
 #define STT_SECTION  (3)
 
 #define ELF64_ST_BIND(info)          ((info) >> 4)

src/as/as.c

@@ -102,7 +102,13 @@ static int output_obj(const char *ofn, Table *label_table, Vector *unresolved) {
       if (!(info->flag & LF_GLOBAL) || !(info->flag & LF_DEFINED))
         continue;
       sym = symtab_add(&symtab, name);
-      sym->st_info = ELF64_ST_INFO(STB_GLOBAL, STT_NOTYPE);
+      int type;
+      switch (info->kind) {
+      case LK_NONE:    type = STT_NOTYPE; break;
+      case LK_FUNC:    type = STT_FUNC; break;
+      case LK_OBJECT:  type = STT_OBJECT; break;
+      }
+      sym->st_info = ELF64_ST_INFO(STB_GLOBAL, type);
       sym->st_value = info->address - section_start_addresses[info->section];
       sym->st_shndx = info->section + 1;  // Symbol index for Local section.
     }

src/as/inst.h

@@ -309,6 +309,7 @@ enum DirectiveType {
   DT_DATA,
   DT_ALIGN,
   DT_P2ALIGN,
+  DT_TYPE,
   DT_BYTE,
   DT_SHORT,
   DT_LONG,

src/as/ir_asm.c

@@ -20,16 +20,17 @@ static LabelInfo *new_label(int section, uintptr_t address) {
   info->section = section;
   info->flag = 0;
   info->address = address;
+  info->kind = LK_NONE;
   return info;
 }
 
-bool add_label_table(Table *label_table, const Name *label, int section, bool define, bool global) {
+LabelInfo *add_label_table(Table *label_table, const Name *label, int section, bool define, bool global) {
   LabelInfo *info = table_get(label_table, label);
   if (info != NULL) {
     if (define) {
       if ((info->flag & LF_DEFINED) != 0) {
         fprintf(stderr, "`%.*s' already defined\n", NAMES(label));
-        return false;
+        return NULL;
       }
       info->address = 1;
       info->section = section;
@@ -42,7 +43,7 @@ bool add_label_table(Table *label_table, const Name *label, int section, bool de
     info->flag |= LF_DEFINED;
   if (global)
     info->flag |= LF_GLOBAL;
-  return true;
+  return info;
 }
 
 IR *new_ir_label(const Name *label) {

src/as/ir_asm.h

@@ -15,13 +15,20 @@ typedef struct Vector Vector;
 #define LF_GLOBAL   (1 << 0)
 #define LF_DEFINED  (1 << 1)
 
+enum LabelKind {
+  LK_NONE,
+  LK_FUNC,
+  LK_OBJECT,
+};
+
 typedef struct {
   int section;
   int flag;
   uintptr_t address;
+  enum LabelKind kind;
 } LabelInfo;
 
-bool add_label_table(Table *label_table, const Name *label, int section, bool define, bool global);
+LabelInfo *add_label_table(Table *label_table, const Name *label, int section, bool define, bool global);
 
 enum UnresolvedKind {
   UNRES_EXTERN,

src/as/parse_asm.c

@@ -219,6 +219,7 @@ static const char *kDirectiveTable[] = {
   "data",
   "align",
   "p2align",
+  "type",
   "byte",
   "short",
   "long",
@@ -403,13 +404,28 @@ static const Name *parse_label(ParseInfo *info) {
     return alloc_name(start + 1, p - 1, false);
   }
 
-  if (!is_label_first_chr(*p))
+  unsigned char *q = (unsigned char*)p;
+  int uc = *q;
+  int ucc = isutf8first(uc) - 1;
+  if (!(ucc > 0 || is_label_first_chr(uc)))
     return NULL;
 
-  do {
-    ++p;
-  } while (is_label_chr(*p));
-  info->p = p;
+  for (;;) {
+    uc = *++q;
+    if (ucc > 0) {
+      if (!isutf8follow(uc)) {
+        parse_error(info, "Illegal byte sequence");
+        return NULL;
+      }
+      --ucc;
+      continue;
+    }
+    if ((ucc = isutf8first(uc) - 1) > 0)
+      continue;
+    if (!is_label_chr(uc))
+      break;
+  }
+  info->p = p = (char*)q;
   return alloc_name(start, p, false);
 }
 
@@ -1106,6 +1122,35 @@ void handle_directive(ParseInfo *info, enum DirectiveType dir, Vector **section_
     }
     break;
 
+  case DT_TYPE:
+    {
+      const Name *label = parse_label(info);
+      if (label == NULL) {
+        parse_error(info, ".comm: label expected");
+        break;
+      }
+      if (*info->p != ',') {
+        parse_error(info, ".comm: `,' expected");
+        break;
+      }
+      info->p = skip_whitespaces(info->p + 1);
+      enum LabelKind kind = LK_NONE;
+      if (strcmp(info->p, "@function") == 0) {
+        kind = LK_FUNC;
+      } else if (strcmp(info->p, "@object") == 0) {
+        kind = LK_OBJECT;
+      } else {
+        parse_error(info, "illegal .type");
+        break;
+      }
+
+      LabelInfo *info = add_label_table(label_table, label, current_section, false, false);
+      if (info != NULL) {
+        info->kind = kind;
+      }
+    }
+    break;
+
   case DT_BYTE:
   case DT_SHORT:
   case DT_LONG:

src/cc/arch/aarch64/emit_code.c

@@ -168,6 +168,9 @@ static void emit_defun(Function *func) {
     _LOCAL(label);
   }
   EMIT_ALIGN(4);
+#if XCC_TARGET_PLATFORM != XCC_PLATFORM_APPLE
+  EMIT_ASM(".type", fmt("%.*s", NAMES(func->name)), "@function");
+#endif
   EMIT_LABEL(label);
 
   bool no_stmt = true;

src/cc/arch/riscv64/emit_code.c

@@ -143,6 +143,9 @@ static void emit_defun(Function *func) {
     _LOCAL(label);
   }
   EMIT_ALIGN(2);
+#if XCC_TARGET_PLATFORM != XCC_PLATFORM_APPLE
+  EMIT_ASM(".type", fmt("%.*s", NAMES(func->name)), "@function");
+#endif
   EMIT_LABEL(label);
 
   bool no_stmt = true;

src/cc/arch/x64/emit_code.c

@@ -165,6 +165,9 @@ static void emit_defun(Function *func) {
     label = quote_label(label);
     _LOCAL(label);
   }
+#if XCC_TARGET_PLATFORM != XCC_PLATFORM_APPLE
+  EMIT_ASM(".type", fmt("%.*s", NAMES(func->name)), "@function");
+#endif
   EMIT_LABEL(label);
 
   bool no_stmt = true;

src/cc/backend/emit_util.c

@@ -244,6 +244,9 @@ void emit_varinfo(const VarInfo *varinfo, const Initializer *init) {
     label = quote_label(label);
     _LOCAL(label);
   }
+#if XCC_TARGET_PLATFORM != XCC_PLATFORM_APPLE
+  EMIT_ASM(".type", fmt("%.*s", NAMES(name)), "@object");
+#endif
 
   if (init != NULL) {
     EMIT_ALIGN(align_size(varinfo->type));

src/ld/elfobj.c

@@ -91,7 +91,7 @@ static bool load_symtab(ElfObj *elfobj) {
     for (uint32_t i = 0; i < count; ++i) {
       Elf64_Sym *sym = &symbols[i];
       unsigned char type = ELF64_ST_TYPE(sym->st_info);
-      if (type == STT_NOTYPE && str[sym->st_name] != '\0') {
+      if (type != STT_SECTION && str[sym->st_name] != '\0') {
         const Name *name = alloc_name(&str[sym->st_name], NULL, false);
         table_put(symbol_table, name, sym);
       }