1 files changed, 31 insertions, 4 deletions

diff --git a/src/compiler.c b/src/compiler.c
index 8c3266c..39cbb00 100644
--- a/src/compiler.c
+++ b/src/compiler.c
@@ -33,7 +33,7 @@ static CHECK_RESULT int create_default_type(amal_compiler *compiler, const char
     return_if_error(structdecl_init(struct_decl, &compiler->root_scope, &compiler->allocator));
 
     return_if_error(arena_allocator_alloc(&compiler->allocator, sizeof(LhsExpr), (void**)lhs_expr));
-    lhsexpr_init(*lhs_expr, bool_true, bool_true, bool_true, create_buffer_view(name, strnlen(name, PATH_MAX)));
+    lhsexpr_init(*lhs_expr, DECL_FLAG_EXTERN | DECL_FLAG_PUB | DECL_FLAG_CONST, create_buffer_view(name, strnlen(name, PATH_MAX)));
     return_if_error(ast_create(&compiler->allocator, struct_decl, AST_STRUCT_DECL, &(*lhs_expr)->rhs_expr));
     return_if_error(ast_create(&compiler->allocator, *lhs_expr, AST_LHS, &expr));
     expr->resolve_data.type = *lhs_expr;
@@ -540,7 +540,6 @@ int amal_compiler_load_file(amal_compiler_options *options, amal_program *progra
 
 int amal_compiler_internal_load_file(amal_compiler *self, const char *filepath, FileScopeReference **file_scope) {
     int result;
-    BufferView filepath_view;
     ParserThreadData *parser_thread_data;
     ThreadWorkData thread_work_data;
     bool main_job;
@@ -548,9 +547,8 @@ int amal_compiler_internal_load_file(amal_compiler *self, const char *filepath,
 
     return_if_error(try_create_file_scope(self, filepath, file_scope, &new_entry));
     assert(file_scope && *file_scope && (*file_scope)->canonical_path.data);
-    filepath_view = create_buffer_view((*file_scope)->canonical_path.data, (*file_scope)->canonical_path.size);
     if(!new_entry) {
-        amal_log_info("amal_compiler_load_file: file already parsed: %.*s", filepath_view.size, filepath_view.data);
+        amal_log_info("amal_compiler_load_file: file already parsed: %.*s", (*file_scope)->canonical_path.size, (*file_scope)->canonical_path.data);
         return 0;
     }
 
@@ -575,11 +573,40 @@ int amal_compiler_internal_load_file(amal_compiler *self, const char *filepath,
             and writing it to a file, which is an IO bottlenecked operation and it won't benefit from multithreading
             and may even lose performance because of it.
         */
+        const BufferView main_func_name = { "main", 4 };
+        LhsExpr *main_func_expr;
 
         return_if_error(amal_compiler_load_file_join_threads(self));
         assert(amal_compiler_check_all_threads_done(self));
         amal_log_info("Finished parsing all files, resolving AST");
 
+        main_func_expr = structdecl_get_field_by_name(&(*file_scope)->parser->struct_decl, main_func_name);
+        if(!main_func_expr) {
+            amal_log_error("main function missing from start file \"%.*s\"", (*file_scope)->canonical_path.size, (*file_scope)->canonical_path.data);
+            return AMAL_COMPILER_ERR;
+        }
+
+        if(!main_func_expr->rhs_expr || main_func_expr->rhs_expr->type != AST_FUNCTION_DECL) {
+            amal_log_error("main exists in start file \"%.*s\" but it's not an non-extern function", (*file_scope)->canonical_path.size, (*file_scope)->canonical_path.data);
+            return AMAL_COMPILER_ERR;
+        }
+
+        if(!LHS_EXPR_IS_CONST(main_func_expr)) {
+            amal_log_error("main function in start file \"%.*s\" has to be const", (*file_scope)->canonical_path.size, (*file_scope)->canonical_path.data);
+            return AMAL_COMPILER_ERR;
+        }
+
+        if(LHS_EXPR_IS_EXTERN(main_func_expr)) {
+            amal_log_error("main function in start file \"%.*s\" can't be declared as extern", (*file_scope)->canonical_path.size, (*file_scope)->canonical_path.data);
+            return AMAL_COMPILER_ERR;
+        }
+
+        /*
+            The main function is the start file needs to be exported, so it's accessible in the program execution
+            to find the entry (main) function.
+        */
+        main_func_expr->decl_flags |= DECL_FLAG_EXPORT;
+
         return_if_error(amal_compiler_dispatch_generic(self, THREAD_WORK_RESOLVE_AST));
         assert(amal_compiler_check_all_threads_done(self));
         amal_log_info("Finished resolving AST, generating SSA");