self_hosted_compiler

self_hosted/create_llvm_ir.jou

@@ -858,7 +858,7 @@ def file_defines_global_var(ast: AstFile*, name: byte*) -> bool:
     return False
 
 
-def create_llvm_ir(ast: AstFile*, ft: FileTypes*) -> LLVMModule*:
+def create_llvm_ir(ast: AstFile*, ft: FileTypes*, checkmain: bool) -> LLVMModule*:
     module = LLVMModuleCreateWithName(ast->path)
     LLVMSetTarget(module, target.triple)
     LLVMSetDataLayout(module, target.data_layout)
@@ -874,9 +874,12 @@ def create_llvm_ir(ast: AstFile*, ft: FileTypes*) -> LLVMModule*:
         builder = LLVMCreateBuilder(),
         file_types = ft
     }
+    mainflag: bool = False
 
     for s = ast->body.statements; s < &ast->body.statements[ast->body.nstatements]; s++:
         if s->kind == AstStatementKind::Function and s->function.body.nstatements > 0:
+            if strcmp((&s->function.signature)->name, "main") == 0:
+                mainflag = True
             a2i.define_function_or_method(&s->function, NULL)
         elif s->kind == AstStatementKind::Class:
             classdef = &s->classdef
@@ -889,5 +892,9 @@ def create_llvm_ir(ast: AstFile*, ft: FileTypes*) -> LLVMModule*:
             # TODO: need to handle some others?
             pass
 
+    if not mainflag and checkmain:
+        l: Location = Location{path = ast->path, lineno = 0}
+        fail(l, "missing `main` function to execute the program")
+
     LLVMDisposeBuilder(a2i.builder)
     return module

self_hosted/main.jou

@@ -347,10 +347,14 @@ class Compiler:
         paths = self->get_object_file_paths()
 
         for i = 0; i < self->nfiles; i++:
+            checkmain: bool = False
             if self->verbosity >= 1:
                 printf("Build LLVM IR: %s\n", self->files[i].ast.path)
 
-            module = create_llvm_ir(&self->files[i].ast, &self->files[i].typectx)
+            if strcmp(self->args->main_path, self->files[i].ast.path) == 0:
+                checkmain = True
+
+            module = create_llvm_ir(&self->files[i].ast, &self->files[i].typectx, checkmain)
             if self->verbosity >= 2:
                 # Don't want to use LLVMDumpModule() because it dumps to stdout.
                 # When redirected, stdout and stderr tend to get mixed up into a weird order.

self_hosted/runs_wrong.txt

@@ -16,3 +16,4 @@ tests/syntax_error/assign_to_None.jou
 tests/syntax_error/None_as_value.jou
 tests/should_succeed/method_by_value.jou
 tests/wrong_type/self_annotation.jou
+tests/should_succeed/file.jou