From bedf01796b20b7aaac5f18c0834b9ea1801cd1cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Tue, 9 Jul 2024 19:58:06 +0800
Subject: [PATCH 01/26] check for main

---
 src/codegen.c | 17 +++++++++++++++--
 src/main.c    | 18 ++++++++++++++----
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/src/codegen.c b/src/codegen.c
index 364e77eb..9aaa83c4 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -497,8 +497,10 @@ static void codegen_function_or_method_def(struct State *st, const CfGraph *cfg)
     free(st->llvm_locals);
 }
 
-LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft)
+LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft, bool checkmain)
 {
+    bool mainflag = false;
+
     struct State st = {
         .module = LLVMModuleCreateWithName(cfgfile->filename),
         .builder = LLVMCreateBuilder(),
@@ -514,8 +516,19 @@ LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft)
             LLVMSetInitializer(globalptr, LLVMConstNull(t));
     }
 
-    for (CfGraph **g = cfgfile->graphs.ptr; g < End(cfgfile->graphs); g++)
+    for (CfGraph **g = cfgfile->graphs.ptr; g < End(cfgfile->graphs); g++) {
+        if (strcmp((*g)->signature.name, "main") == 0)
+            mainflag = true;
         codegen_function_or_method_def(&st, *g);
+    }
+    
+    if (checkmain && mainflag == false) {
+        struct Location l = {
+            .filename = cfgfile->filename,
+            .lineno = 1,
+        };
+        fail(l, "missing `main` function to execute the program");
+    }
 
     LLVMDisposeBuilder(st.builder);
     return st.module;
diff --git a/src/main.c b/src/main.c
index c37a9882..b47a5766 100644
--- a/src/main.c
+++ b/src/main.c
@@ -243,7 +243,7 @@ static void parse_all_pending_files(struct CompileState *compst)
     free(compst->parse_queue.ptr);
 }
 
-static char *compile_ast_to_object_file(struct FileState *fs)
+static char *compile_ast_to_object_file(struct FileState *fs, bool checkmain)
 {
     if (command_line_args.verbosity >= 1)
         printf("Building Control Flow Graphs: %s\n", fs->path);
@@ -265,7 +265,7 @@ static char *compile_ast_to_object_file(struct FileState *fs)
     if (command_line_args.verbosity >= 1)
         printf("Building LLVM IR: %s\n", fs->path);
 
-    LLVMModuleRef mod = codegen(&cfgfile, &fs->types);
+    LLVMModuleRef mod = codegen(&cfgfile, &fs->types, checkmain);
     free_control_flow_graphs(&cfgfile);
 
     if (command_line_args.verbosity >= 2)
@@ -439,7 +439,8 @@ int main(int argc, char **argv)
         printf("Data layout: %s\n", get_target()->data_layout);
     }
 
-    if (command_line_args.tokenize_only || command_line_args.parse_only) {
+    if (command_line_args.tokenize_only || command_line_args.parse_only)
+    {
         FILE *f = open_the_file(command_line_args.infile, NULL);
         Token *tokens = tokenize(f, command_line_args.infile);
         fclose(f);
@@ -490,7 +491,16 @@ int main(int argc, char **argv)
 
     char **objpaths = calloc(sizeof objpaths[0], compst.files.len + 1);
     for (struct FileState *fs = compst.files.ptr; fs < End(compst.files); fs++)
-        objpaths[fs - compst.files.ptr] = compile_ast_to_object_file(fs);
+    {
+        if (strcmp(command_line_args.infile, fs->path) == 0)
+        {
+            objpaths[fs - compst.files.ptr] = compile_ast_to_object_file(fs, true);
+        }
+        else
+        {
+            objpaths[fs - compst.files.ptr] = compile_ast_to_object_file(fs, false);
+        }
+    }
 
     for (struct FileState *fs = compst.files.ptr; fs < End(compst.files); fs++) {
         free_ast(&fs->ast);

From c41f337315e79729844766724504c678bd6fc8f7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Tue, 9 Jul 2024 19:59:20 +0800
Subject: [PATCH 02/26] add test

---
 tests/other_errors/missing_main_function.jou | 4 ++++
 1 file changed, 4 insertions(+)
 create mode 100644 tests/other_errors/missing_main_function.jou

diff --git a/tests/other_errors/missing_main_function.jou b/tests/other_errors/missing_main_function.jou
new file mode 100644
index 00000000..1ea2cacb
--- /dev/null
+++ b/tests/other_errors/missing_main_function.jou
@@ -0,0 +1,4 @@
+# Error: missing `main` function to execute the program
+def test() -> None:
+    _ = "lol no main func"
+

From f6ddffb64229a8d536c7cb3d288729fc628e9e62 Mon Sep 17 00:00:00 2001
From: littlewhitecloud <littlewhitecloud@users.noreply.github.com>
Date: Tue, 9 Jul 2024 12:03:02 +0000
Subject: [PATCH 03/26] Change files to use LF line endings

---
 tests/other_errors/missing_main_function.jou | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tests/other_errors/missing_main_function.jou b/tests/other_errors/missing_main_function.jou
index 1ea2cacb..83c6d85d 100644
--- a/tests/other_errors/missing_main_function.jou
+++ b/tests/other_errors/missing_main_function.jou
@@ -1,4 +1,4 @@
-# Error: missing `main` function to execute the program
-def test() -> None:
-    _ = "lol no main func"
-
+# Error: missing `main` function to execute the program
+def test() -> None:
+    _ = "lol no main func"
+

From b9f835b1e145a1d95aa0673452607169c5e9fed7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Tue, 9 Jul 2024 20:04:36 +0800
Subject: [PATCH 04/26] forget it

---
 src/jou_compiler.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/jou_compiler.h b/src/jou_compiler.h
index c505e4a4..cc990c22 100644
--- a/src/jou_compiler.h
+++ b/src/jou_compiler.h
@@ -628,7 +628,7 @@ AstFile parse(const Token *tokens, const char *stdlib_path);
 // Type checking happens between parsing and building CFGs.
 CfGraphFile build_control_flow_graphs(const AstFile *ast, FileTypes *ft);
 void simplify_control_flow_graphs(const CfGraphFile *cfgfile);
-LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft);
+LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft, bool checkmain);
 char *compile_to_object_file(LLVMModuleRef module);
 char *get_default_exe_path(void);
 void run_linker(const char *const *objpaths, const char *exepath);

From f39c38292ae8542069732a4aa6f4310baaeb31d9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Tue, 9 Jul 2024 20:06:36 +0800
Subject: [PATCH 05/26] del tra line

---
 src/codegen.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/codegen.c b/src/codegen.c
index 9aaa83c4..4ea198e1 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -521,7 +521,7 @@ LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft, bool chec
             mainflag = true;
         codegen_function_or_method_def(&st, *g);
     }
-    
+
     if (checkmain && mainflag == false) {
         struct Location l = {
             .filename = cfgfile->filename,

From 05330b00803de65ea721ff7ab69e6741cac769d4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Fri, 12 Jul 2024 22:05:52 +0800
Subject: [PATCH 06/26] don't need a linenumber anymore

---
 src/codegen.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/codegen.c b/src/codegen.c
index 4ea198e1..35bcc6b0 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -525,7 +525,7 @@ LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft, bool chec
     if (checkmain && mainflag == false) {
         struct Location l = {
             .filename = cfgfile->filename,
-            .lineno = 1,
+            .lineno = 0,
         };
         fail(l, "missing `main` function to execute the program");
     }

From ccda81f4f15c6f66e09ebbf7f5868d72e87495d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Fri, 12 Jul 2024 22:17:49 +0800
Subject: [PATCH 07/26] Update missing_main_function.jou

---
 tests/other_errors/missing_main_function.jou | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tests/other_errors/missing_main_function.jou b/tests/other_errors/missing_main_function.jou
index 83c6d85d..dbf251de 100644
--- a/tests/other_errors/missing_main_function.jou
+++ b/tests/other_errors/missing_main_function.jou
@@ -1,4 +1,3 @@
-# Error: missing `main` function to execute the program
 def test() -> None:
     _ = "lol no main func"
-
+    # Output: missing `main` function to execute the program

From 3f1622fdb608ea9868ab946fddefe97ad5c8117d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Fri, 12 Jul 2024 23:02:37 +0800
Subject: [PATCH 08/26] self_hosted_compiler

---
 self_hosted/create_llvm_ir.jou | 9 ++++++++-
 self_hosted/main.jou           | 6 +++++-
 self_hosted/runs_wrong.txt     | 1 +
 3 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index ddd0d4ff..764a94ee 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/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
diff --git a/self_hosted/main.jou b/self_hosted/main.jou
index 8be8f3aa..18297ec2 100644
--- a/self_hosted/main.jou
+++ b/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.
diff --git a/self_hosted/runs_wrong.txt b/self_hosted/runs_wrong.txt
index 429a878e..3a2f2392 100644
--- a/self_hosted/runs_wrong.txt
+++ b/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

From 73dc4268f2eed170e9a1e16bd17c9238e163a887 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Fri, 12 Jul 2024 23:05:26 +0800
Subject: [PATCH 09/26] remove --fix

---
 self_hosted/runs_wrong.txt | 1 -
 1 file changed, 1 deletion(-)

diff --git a/self_hosted/runs_wrong.txt b/self_hosted/runs_wrong.txt
index 3a2f2392..429a878e 100644
--- a/self_hosted/runs_wrong.txt
+++ b/self_hosted/runs_wrong.txt
@@ -16,4 +16,3 @@ 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

From 3055a32ae94e5fa7f01d305c9e24e791e56cdb26 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 12:05:17 +0800
Subject: [PATCH 10/26] output

---
 tests/other_errors/missing_main_function.jou | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/other_errors/missing_main_function.jou b/tests/other_errors/missing_main_function.jou
index dbf251de..4f4cbb4f 100644
--- a/tests/other_errors/missing_main_function.jou
+++ b/tests/other_errors/missing_main_function.jou
@@ -1,3 +1,3 @@
+# Output: compiler error in file "tests/other_errors/missing_main_function.jou": missing `main` function to execute the program
 def test() -> None:
     _ = "lol no main func"
-    # Output: missing `main` function to execute the program

From caa512cd21c38f3a3ab5e9864dea6df45f6fa981 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 13:04:26 +0800
Subject: [PATCH 11/26] check for import

---
 src/codegen.c | 16 +++++++++++-----
 src/main.c    |  8 ++++++++
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/src/codegen.c b/src/codegen.c
index 35bcc6b0..8fe8c1b1 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -516,20 +516,26 @@ LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft, bool chec
             LLVMSetInitializer(globalptr, LLVMConstNull(t));
     }
 
-    for (CfGraph **g = cfgfile->graphs.ptr; g < End(cfgfile->graphs); g++) {
-        if (strcmp((*g)->signature.name, "main") == 0)
+    for (CfGraph **g = cfgfile->graphs.ptr; g < End(cfgfile->graphs); g++)
+        if (strcmp((*g)->signature.name, "main") == 0) {
             mainflag = true;
-        codegen_function_or_method_def(&st, *g);
-    }
+            break;
+        }
 
-    if (checkmain && mainflag == false) {
+
+    if (checkmain && mainflag == false)
+    {
         struct Location l = {
             .filename = cfgfile->filename,
             .lineno = 0,
         };
+        // check main function for the file
         fail(l, "missing `main` function to execute the program");
     }
 
+    for (CfGraph **g = cfgfile->graphs.ptr; g < End(cfgfile->graphs); g++)
+        codegen_function_or_method_def(&st, *g);
+
     LLVMDisposeBuilder(st.builder);
     return st.module;
 }
diff --git a/src/main.c b/src/main.c
index b47a5766..77988796 100644
--- a/src/main.c
+++ b/src/main.c
@@ -392,6 +392,14 @@ static void add_imported_symbols(struct CompileState *compst)
             Append(&seen_before, from);
 
             for (struct ExportSymbol *es = from->pending_exports; es->name[0]; es++) {
+                if (strcmp(es->name, "main") == 0)
+                {
+                    struct Location l = {
+                        .filename = from->path,
+                        .lineno = 0,
+                    };
+                    fail(l, "imported file should not have `main` function");
+                }
                 if (command_line_args.verbosity >= 2) {
                     const char *kindstr;
                     switch(es->kind) {

From 86992de935c7affb269edc20996c3d2bb3e17e41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 13:04:48 +0800
Subject: [PATCH 12/26] check for import

---
 self_hosted/main.jou | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/self_hosted/main.jou b/self_hosted/main.jou
index 18297ec2..b9aabc9d 100644
--- a/self_hosted/main.jou
+++ b/self_hosted/main.jou
@@ -258,6 +258,9 @@ class Compiler:
                             "  %s: imported in %s, exported in %s\n",
                             exp->name, src->ast.path, dest->ast.path,
                         )
+                    if strcmp(exp->name, "main") == 0:
+                        l: Location = Location{path=src->ast.path, lineno = 0}
+                        fail(l, "imported file should not have `main` function")
                     check_ast_and_import_conflicts(&dest->ast, exp)
                     dest->typectx.add_imported_symbol(exp)
 

From 26214bd37df93a5fa66d1022f67b0b36f3be8952 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 13:05:31 +0800
Subject: [PATCH 13/26] add test

---
 tests/other_errors/import_file_with_main.jou | 7 +++++++
 tests/other_errors/imported.jou              | 9 +++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 tests/other_errors/import_file_with_main.jou
 create mode 100644 tests/other_errors/imported.jou

diff --git a/tests/other_errors/import_file_with_main.jou b/tests/other_errors/import_file_with_main.jou
new file mode 100644
index 00000000..f03af8d6
--- /dev/null
+++ b/tests/other_errors/import_file_with_main.jou
@@ -0,0 +1,7 @@
+import "./imported.jou"
+import "stdlib/io.jou"
+
+def main() -> int:
+    printf("%d", add(114, 514))
+
+    return 0
diff --git a/tests/other_errors/imported.jou b/tests/other_errors/imported.jou
new file mode 100644
index 00000000..e695b03a
--- /dev/null
+++ b/tests/other_errors/imported.jou
@@ -0,0 +1,9 @@
+import "stdlib/io.jou"
+
+def add(a: int, b: int) -> int:
+    return a + b
+
+def main() -> int: # Output: compiler error in file "tests/other_errors/imported.jou": imported file should not have `main` function
+    printf("%d", add(1, 2))
+
+    return 0

From f231a200aa451166962f74a1c7eb2b68c5f21230 Mon Sep 17 00:00:00 2001
From: littlewhitecloud <littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 05:06:29 +0000
Subject: [PATCH 14/26] Change files to use LF line endings

---
 tests/other_errors/import_file_with_main.jou | 14 +++++++-------
 tests/other_errors/imported.jou              | 18 +++++++++---------
 2 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/tests/other_errors/import_file_with_main.jou b/tests/other_errors/import_file_with_main.jou
index f03af8d6..4f9171f5 100644
--- a/tests/other_errors/import_file_with_main.jou
+++ b/tests/other_errors/import_file_with_main.jou
@@ -1,7 +1,7 @@
-import "./imported.jou"
-import "stdlib/io.jou"
-
-def main() -> int:
-    printf("%d", add(114, 514))
-
-    return 0
+import "./imported.jou"
+import "stdlib/io.jou"
+
+def main() -> int:
+    printf("%d", add(114, 514))
+
+    return 0
diff --git a/tests/other_errors/imported.jou b/tests/other_errors/imported.jou
index e695b03a..df6f5d81 100644
--- a/tests/other_errors/imported.jou
+++ b/tests/other_errors/imported.jou
@@ -1,9 +1,9 @@
-import "stdlib/io.jou"
-
-def add(a: int, b: int) -> int:
-    return a + b
-
-def main() -> int: # Output: compiler error in file "tests/other_errors/imported.jou": imported file should not have `main` function
-    printf("%d", add(1, 2))
-
-    return 0
+import "stdlib/io.jou"
+
+def add(a: int, b: int) -> int:
+    return a + b
+
+def main() -> int: # Output: compiler error in file "tests/other_errors/imported.jou": imported file should not have `main` function
+    printf("%d", add(1, 2))
+
+    return 0

From f9f9dfaf42922cc30481f4bbf8aa946fc7df0fb8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 15:46:07 +0800
Subject: [PATCH 15/26] Delete tests/other_errors/imported.jou

---
 tests/other_errors/imported.jou | 9 ---------
 1 file changed, 9 deletions(-)
 delete mode 100644 tests/other_errors/imported.jou

diff --git a/tests/other_errors/imported.jou b/tests/other_errors/imported.jou
deleted file mode 100644
index df6f5d81..00000000
--- a/tests/other_errors/imported.jou
+++ /dev/null
@@ -1,9 +0,0 @@
-import "stdlib/io.jou"
-
-def add(a: int, b: int) -> int:
-    return a + b
-
-def main() -> int: # Output: compiler error in file "tests/other_errors/imported.jou": imported file should not have `main` function
-    printf("%d", add(1, 2))
-
-    return 0

From 3a8615accd92fb7ec8d8aece5694991b62dba18e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 15:47:10 +0800
Subject: [PATCH 16/26] update test

---
 tests/other_errors/import_file_with_main.jou | 14 +++++++-------
 tests/other_errors/imported/imported.jou     | 10 ++++++++++
 2 files changed, 17 insertions(+), 7 deletions(-)
 create mode 100644 tests/other_errors/imported/imported.jou

diff --git a/tests/other_errors/import_file_with_main.jou b/tests/other_errors/import_file_with_main.jou
index 4f9171f5..ff4a1c08 100644
--- a/tests/other_errors/import_file_with_main.jou
+++ b/tests/other_errors/import_file_with_main.jou
@@ -1,7 +1,7 @@
-import "./imported.jou"
-import "stdlib/io.jou"
-
-def main() -> int:
-    printf("%d", add(114, 514))
-
-    return 0
+import "./imported/imported.jou"
+import "stdlib/io.jou"
+
+def main() -> int: # Output: compiler error in file "tests/other_errors/imported/imported.jou": imported file should not have `main` function
+    printf("%d", add(114, 514))
+
+    return 0
diff --git a/tests/other_errors/imported/imported.jou b/tests/other_errors/imported/imported.jou
new file mode 100644
index 00000000..846baf44
--- /dev/null
+++ b/tests/other_errors/imported/imported.jou
@@ -0,0 +1,10 @@
+# This file is meant to be imported, not ran directly.
+
+import "stdlib/io.jou"
+
+def add(a: int, b: int) -> int:
+    return a + b
+
+def main() -> int:
+    printf("%d", add(1, 2))
+    return 0

From 54c6dfd466f88b0aa3b834af7bfce0f3509600ee Mon Sep 17 00:00:00 2001
From: littlewhitecloud <littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 07:47:25 +0000
Subject: [PATCH 17/26] Change files to use LF line endings

---
 tests/other_errors/import_file_with_main.jou | 14 +++++++-------
 tests/other_errors/imported/imported.jou     | 20 ++++++++++----------
 2 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/tests/other_errors/import_file_with_main.jou b/tests/other_errors/import_file_with_main.jou
index ff4a1c08..687dd656 100644
--- a/tests/other_errors/import_file_with_main.jou
+++ b/tests/other_errors/import_file_with_main.jou
@@ -1,7 +1,7 @@
-import "./imported/imported.jou"
-import "stdlib/io.jou"
-
-def main() -> int: # Output: compiler error in file "tests/other_errors/imported/imported.jou": imported file should not have `main` function
-    printf("%d", add(114, 514))
-
-    return 0
+import "./imported/imported.jou"
+import "stdlib/io.jou"
+
+def main() -> int: # Output: compiler error in file "tests/other_errors/imported/imported.jou": imported file should not have `main` function
+    printf("%d", add(114, 514))
+
+    return 0
diff --git a/tests/other_errors/imported/imported.jou b/tests/other_errors/imported/imported.jou
index 846baf44..332d8231 100644
--- a/tests/other_errors/imported/imported.jou
+++ b/tests/other_errors/imported/imported.jou
@@ -1,10 +1,10 @@
-# This file is meant to be imported, not ran directly.
-
-import "stdlib/io.jou"
-
-def add(a: int, b: int) -> int:
-    return a + b
-
-def main() -> int:
-    printf("%d", add(1, 2))
-    return 0
+# This file is meant to be imported, not ran directly.
+
+import "stdlib/io.jou"
+
+def add(a: int, b: int) -> int:
+    return a + b
+
+def main() -> int:
+    printf("%d", add(1, 2))
+    return 0

From 8d86e969f381e44c6bf8a2d1481e746ac1abc611 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 22:27:17 +0800
Subject: [PATCH 18/26] move

---
 tests/should_succeed/import_cycle.jou | 22 ----------------------
 1 file changed, 22 deletions(-)
 delete mode 100644 tests/should_succeed/import_cycle.jou

diff --git a/tests/should_succeed/import_cycle.jou b/tests/should_succeed/import_cycle.jou
deleted file mode 100644
index 88ca31b6..00000000
--- a/tests/should_succeed/import_cycle.jou
+++ /dev/null
@@ -1,22 +0,0 @@
-import "stdlib/io.jou"
-import "./imported/cycle.jou"
-
-def a(x: int) -> None:
-    printf("a %d\n", x)
-    if x > 0:
-        b(x-1)
-
-# Output: a 10
-# Output: b 9
-# Output: a 8
-# Output: b 7
-# Output: a 6
-# Output: b 5
-# Output: a 4
-# Output: b 3
-# Output: a 2
-# Output: b 1
-# Output: a 0
-def main() -> int:
-    a(10)
-    return 0

From 6ccdab5b719aa6ed31488091e0968fbeeb5a53b8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 22:27:30 +0800
Subject: [PATCH 19/26] move

---
 tests/should_succeed/imported/cycle.jou | 9 ---------
 1 file changed, 9 deletions(-)
 delete mode 100644 tests/should_succeed/imported/cycle.jou

diff --git a/tests/should_succeed/imported/cycle.jou b/tests/should_succeed/imported/cycle.jou
deleted file mode 100644
index eab37a1d..00000000
--- a/tests/should_succeed/imported/cycle.jou
+++ /dev/null
@@ -1,9 +0,0 @@
-# This file is meant to be imported, not ran directly.
-
-import "stdlib/io.jou"
-import "../import_cycle.jou"
-
-def b(x: int) -> None:
-    printf("b %d\n", x)
-    if x > 0:
-        a(x-1)

From 424e17f428343c17c35c057f8fd2fbb1f9b2b8f3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 22:27:52 +0800
Subject: [PATCH 20/26] move

---
 tests/other_errors/import_cycle.jou      | 12 ++++++++++++
 tests/other_errors/imported/cycle.jou    |  9 +++++++++
 tests/other_errors/imported/imported.jou | 20 ++++++++++----------
 3 files changed, 31 insertions(+), 10 deletions(-)
 create mode 100644 tests/other_errors/import_cycle.jou
 create mode 100644 tests/other_errors/imported/cycle.jou

diff --git a/tests/other_errors/import_cycle.jou b/tests/other_errors/import_cycle.jou
new file mode 100644
index 00000000..ba369ae6
--- /dev/null
+++ b/tests/other_errors/import_cycle.jou
@@ -0,0 +1,12 @@
+import "stdlib/io.jou"
+import "./imported/cycle.jou"
+
+def a(x: int) -> None:
+    printf("a %d\n", x)
+    if x > 0:
+        b(x-1)
+
+# Output: compiler error in file "tests/other_errors/import_cycle.jou": imported file should not have `main` function
+def main() -> int:
+    a(10)
+    return 0
diff --git a/tests/other_errors/imported/cycle.jou b/tests/other_errors/imported/cycle.jou
new file mode 100644
index 00000000..eab37a1d
--- /dev/null
+++ b/tests/other_errors/imported/cycle.jou
@@ -0,0 +1,9 @@
+# This file is meant to be imported, not ran directly.
+
+import "stdlib/io.jou"
+import "../import_cycle.jou"
+
+def b(x: int) -> None:
+    printf("b %d\n", x)
+    if x > 0:
+        a(x-1)
diff --git a/tests/other_errors/imported/imported.jou b/tests/other_errors/imported/imported.jou
index 332d8231..846baf44 100644
--- a/tests/other_errors/imported/imported.jou
+++ b/tests/other_errors/imported/imported.jou
@@ -1,10 +1,10 @@
-# This file is meant to be imported, not ran directly.
-
-import "stdlib/io.jou"
-
-def add(a: int, b: int) -> int:
-    return a + b
-
-def main() -> int:
-    printf("%d", add(1, 2))
-    return 0
+# This file is meant to be imported, not ran directly.
+
+import "stdlib/io.jou"
+
+def add(a: int, b: int) -> int:
+    return a + b
+
+def main() -> int:
+    printf("%d", add(1, 2))
+    return 0

From 5370732546ed34b78eefa6dd7b57c007ae987930 Mon Sep 17 00:00:00 2001
From: littlewhitecloud <littlewhitecloud@users.noreply.github.com>
Date: Sat, 13 Jul 2024 14:28:07 +0000
Subject: [PATCH 21/26] Change files to use LF line endings

---
 tests/other_errors/imported/imported.jou | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/tests/other_errors/imported/imported.jou b/tests/other_errors/imported/imported.jou
index 846baf44..332d8231 100644
--- a/tests/other_errors/imported/imported.jou
+++ b/tests/other_errors/imported/imported.jou
@@ -1,10 +1,10 @@
-# This file is meant to be imported, not ran directly.
-
-import "stdlib/io.jou"
-
-def add(a: int, b: int) -> int:
-    return a + b
-
-def main() -> int:
-    printf("%d", add(1, 2))
-    return 0
+# This file is meant to be imported, not ran directly.
+
+import "stdlib/io.jou"
+
+def add(a: int, b: int) -> int:
+    return a + b
+
+def main() -> int:
+    printf("%d", add(1, 2))
+    return 0

From 0e3b24c5e2460ad3d49849df22cfc4b803d661cb Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 18 Aug 2024 00:49:11 +0300
Subject: [PATCH 22/26] New implementation that passes existing tests

---
 src/codegen.c      | 21 +------------------
 src/jou_compiler.h |  2 +-
 src/main.c         | 52 ++++++++++++++++++++++++++--------------------
 3 files changed, 32 insertions(+), 43 deletions(-)

diff --git a/src/codegen.c b/src/codegen.c
index 8fe8c1b1..364e77eb 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -497,10 +497,8 @@ static void codegen_function_or_method_def(struct State *st, const CfGraph *cfg)
     free(st->llvm_locals);
 }
 
-LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft, bool checkmain)
+LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft)
 {
-    bool mainflag = false;
-
     struct State st = {
         .module = LLVMModuleCreateWithName(cfgfile->filename),
         .builder = LLVMCreateBuilder(),
@@ -516,23 +514,6 @@ LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft, bool chec
             LLVMSetInitializer(globalptr, LLVMConstNull(t));
     }
 
-    for (CfGraph **g = cfgfile->graphs.ptr; g < End(cfgfile->graphs); g++)
-        if (strcmp((*g)->signature.name, "main") == 0) {
-            mainflag = true;
-            break;
-        }
-
-
-    if (checkmain && mainflag == false)
-    {
-        struct Location l = {
-            .filename = cfgfile->filename,
-            .lineno = 0,
-        };
-        // check main function for the file
-        fail(l, "missing `main` function to execute the program");
-    }
-
     for (CfGraph **g = cfgfile->graphs.ptr; g < End(cfgfile->graphs); g++)
         codegen_function_or_method_def(&st, *g);
 
diff --git a/src/jou_compiler.h b/src/jou_compiler.h
index cc990c22..c505e4a4 100644
--- a/src/jou_compiler.h
+++ b/src/jou_compiler.h
@@ -628,7 +628,7 @@ AstFile parse(const Token *tokens, const char *stdlib_path);
 // Type checking happens between parsing and building CFGs.
 CfGraphFile build_control_flow_graphs(const AstFile *ast, FileTypes *ft);
 void simplify_control_flow_graphs(const CfGraphFile *cfgfile);
-LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft, bool checkmain);
+LLVMModuleRef codegen(const CfGraphFile *cfgfile, const FileTypes *ft);
 char *compile_to_object_file(LLVMModuleRef module);
 char *get_default_exe_path(void);
 void run_linker(const char *const *objpaths, const char *exepath);
diff --git a/src/main.c b/src/main.c
index 77988796..8eca622d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -243,7 +243,7 @@ static void parse_all_pending_files(struct CompileState *compst)
     free(compst->parse_queue.ptr);
 }
 
-static char *compile_ast_to_object_file(struct FileState *fs, bool checkmain)
+static char *compile_ast_to_object_file(struct FileState *fs)
 {
     if (command_line_args.verbosity >= 1)
         printf("Building Control Flow Graphs: %s\n", fs->path);
@@ -265,7 +265,7 @@ static char *compile_ast_to_object_file(struct FileState *fs, bool checkmain)
     if (command_line_args.verbosity >= 1)
         printf("Building LLVM IR: %s\n", fs->path);
 
-    LLVMModuleRef mod = codegen(&cfgfile, &fs->types, checkmain);
+    LLVMModuleRef mod = codegen(&cfgfile, &fs->types);
     free_control_flow_graphs(&cfgfile);
 
     if (command_line_args.verbosity >= 2)
@@ -392,14 +392,6 @@ static void add_imported_symbols(struct CompileState *compst)
             Append(&seen_before, from);
 
             for (struct ExportSymbol *es = from->pending_exports; es->name[0]; es++) {
-                if (strcmp(es->name, "main") == 0)
-                {
-                    struct Location l = {
-                        .filename = from->path,
-                        .lineno = 0,
-                    };
-                    fail(l, "imported file should not have `main` function");
-                }
                 if (command_line_args.verbosity >= 2) {
                     const char *kindstr;
                     switch(es->kind) {
@@ -426,6 +418,30 @@ static void add_imported_symbols(struct CompileState *compst)
     }
 }
 
+static const AstStatement *find_main_definition(const AstFile *ast)
+{
+    for (int i = 0; i < ast->body.nstatements; i++) {
+        const AstStatement *s = &ast->body.statements[i];
+        if (s->kind == AST_STMT_FUNCTION && !strcmp(s->data.function.signature.name, "main"))
+            return s;
+    }
+    return NULL;
+}
+
+static void check_main_definitions(const struct CompileState *compst)
+{
+    struct FileState *mainfile = find_file(compst, command_line_args.infile);
+
+    for (struct FileState *fs = compst->files.ptr; fs < End(compst->files); fs++) {
+        const AstStatement *maindef = find_main_definition(&fs->ast);
+
+        if (fs != mainfile && maindef)
+            fail(maindef->location, "imported file should not have `main` function");
+        if (fs == mainfile && !maindef)
+            fail((Location){.filename=fs->path, .lineno=0}, "missing `main` function to execute the program");
+    }
+}
+
 static void include_special_stdlib_file(struct CompileState *compst, const char *filename)
 {
     char *path = malloc(strlen(compst->stdlib_path) + strlen(filename) + 123);
@@ -447,8 +463,7 @@ int main(int argc, char **argv)
         printf("Data layout: %s\n", get_target()->data_layout);
     }
 
-    if (command_line_args.tokenize_only || command_line_args.parse_only)
-    {
+    if (command_line_args.tokenize_only || command_line_args.parse_only) {
         FILE *f = open_the_file(command_line_args.infile, NULL);
         Token *tokens = tokenize(f, command_line_args.infile);
         fclose(f);
@@ -499,16 +514,9 @@ int main(int argc, char **argv)
 
     char **objpaths = calloc(sizeof objpaths[0], compst.files.len + 1);
     for (struct FileState *fs = compst.files.ptr; fs < End(compst.files); fs++)
-    {
-        if (strcmp(command_line_args.infile, fs->path) == 0)
-        {
-            objpaths[fs - compst.files.ptr] = compile_ast_to_object_file(fs, true);
-        }
-        else
-        {
-            objpaths[fs - compst.files.ptr] = compile_ast_to_object_file(fs, false);
-        }
-    }
+        objpaths[fs - compst.files.ptr] = compile_ast_to_object_file(fs);
+
+    check_main_definitions(&compst);
 
     for (struct FileState *fs = compst.files.ptr; fs < End(compst.files); fs++) {
         free_ast(&fs->ast);

From f9dcd7ce6b862fc5d724fc64aed6c7797bd66f73 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 18 Aug 2024 00:52:49 +0300
Subject: [PATCH 23/26] Revert test file rename

---
 .../import_cycle.jou                                 | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
 rename tests/{other_errors => should_succeed}/import_cycle.jou (52%)

diff --git a/tests/other_errors/import_cycle.jou b/tests/should_succeed/import_cycle.jou
similarity index 52%
rename from tests/other_errors/import_cycle.jou
rename to tests/should_succeed/import_cycle.jou
index ba369ae6..88ca31b6 100644
--- a/tests/other_errors/import_cycle.jou
+++ b/tests/should_succeed/import_cycle.jou
@@ -6,7 +6,17 @@ def a(x: int) -> None:
     if x > 0:
         b(x-1)
 
-# Output: compiler error in file "tests/other_errors/import_cycle.jou": imported file should not have `main` function
+# Output: a 10
+# Output: b 9
+# Output: a 8
+# Output: b 7
+# Output: a 6
+# Output: b 5
+# Output: a 4
+# Output: b 3
+# Output: a 2
+# Output: b 1
+# Output: a 0
 def main() -> int:
     a(10)
     return 0

From ff40f0f8d4cbd6808341a75e4b9f3c2298fd38f6 Mon Sep 17 00:00:00 2001
From: Akuli <akuviljanen17@gmail.com>
Date: Sun, 18 Aug 2024 01:41:10 +0300
Subject: [PATCH 24/26] now good?

---
 src/main.c                                    | 53 ++++++++++---------
 tests/other_errors/import_file_with_main.jou  |  8 +--
 tests/other_errors/imported/imported.jou      | 10 ----
 .../imported/cycle.jou                        |  0
 4 files changed, 29 insertions(+), 42 deletions(-)
 delete mode 100644 tests/other_errors/imported/imported.jou
 rename tests/{other_errors => should_succeed}/imported/cycle.jou (100%)

diff --git a/src/main.c b/src/main.c
index 8eca622d..23996951 100644
--- a/src/main.c
+++ b/src/main.c
@@ -196,6 +196,16 @@ static FILE *open_the_file(const char *path, const Location *import_location)
     return f;
 }
 
+static bool defines_main(const AstFile *ast)
+{
+    for (int i = 0; i < ast->body.nstatements; i++) {
+        const AstStatement *s = &ast->body.statements[i];
+        if (s->kind == AST_STMT_FUNCTION && !strcmp(s->data.function.signature.name, "main"))
+            return true;
+    }
+    return false;
+}
+
 static void parse_file(struct CompileState *compst, const char *filename, const Location *import_location)
 {
     if (find_file(compst, filename))
@@ -224,6 +234,16 @@ static void parse_file(struct CompileState *compst, const char *filename, const
     if(command_line_args.verbosity >= 2)
         print_ast(&fs.ast);
 
+    // If it's not the file passed on command line, it shouldn't define main()
+    if (strcmp(filename, command_line_args.infile) && defines_main(&fs.ast)) {
+        /*
+        Set error location to import, so user immediately knows which file
+        imports something that defines main().
+        */
+        assert(import_location);
+        fail(*import_location, "imported file should not have `main` function");
+    }
+
     for (const AstImport *imp = fs.ast.imports.ptr; imp < End(fs.ast.imports); imp++) {
         Append(&compst->parse_queue, (struct ParseQueueItem){
             .filename = imp->resolved_path,
@@ -418,30 +438,6 @@ static void add_imported_symbols(struct CompileState *compst)
     }
 }
 
-static const AstStatement *find_main_definition(const AstFile *ast)
-{
-    for (int i = 0; i < ast->body.nstatements; i++) {
-        const AstStatement *s = &ast->body.statements[i];
-        if (s->kind == AST_STMT_FUNCTION && !strcmp(s->data.function.signature.name, "main"))
-            return s;
-    }
-    return NULL;
-}
-
-static void check_main_definitions(const struct CompileState *compst)
-{
-    struct FileState *mainfile = find_file(compst, command_line_args.infile);
-
-    for (struct FileState *fs = compst->files.ptr; fs < End(compst->files); fs++) {
-        const AstStatement *maindef = find_main_definition(&fs->ast);
-
-        if (fs != mainfile && maindef)
-            fail(maindef->location, "imported file should not have `main` function");
-        if (fs == mainfile && !maindef)
-            fail((Location){.filename=fs->path, .lineno=0}, "missing `main` function to execute the program");
-    }
-}
-
 static void include_special_stdlib_file(struct CompileState *compst, const char *filename)
 {
     char *path = malloc(strlen(compst->stdlib_path) + strlen(filename) + 123);
@@ -516,7 +512,14 @@ int main(int argc, char **argv)
     for (struct FileState *fs = compst.files.ptr; fs < End(compst.files); fs++)
         objpaths[fs - compst.files.ptr] = compile_ast_to_object_file(fs);
 
-    check_main_definitions(&compst);
+    /*
+    Check for missing main() as late as possible, so that other errors come first.
+    This way Jou users can work on other functions before main() function is written.
+    */
+    struct FileState *mainfile = find_file(&compst, command_line_args.infile);
+    assert(mainfile);
+    if (!defines_main(&mainfile->ast))
+        fail((Location){.filename=mainfile->path, .lineno=0}, "missing `main` function to execute the program");
 
     for (struct FileState *fs = compst.files.ptr; fs < End(compst.files); fs++) {
         free_ast(&fs->ast);
diff --git a/tests/other_errors/import_file_with_main.jou b/tests/other_errors/import_file_with_main.jou
index 687dd656..4fe9630e 100644
--- a/tests/other_errors/import_file_with_main.jou
+++ b/tests/other_errors/import_file_with_main.jou
@@ -1,7 +1 @@
-import "./imported/imported.jou"
-import "stdlib/io.jou"
-
-def main() -> int: # Output: compiler error in file "tests/other_errors/imported/imported.jou": imported file should not have `main` function
-    printf("%d", add(114, 514))
-
-    return 0
+import "../../examples/hello.jou"  # Error: imported file should not have `main` function
diff --git a/tests/other_errors/imported/imported.jou b/tests/other_errors/imported/imported.jou
deleted file mode 100644
index 332d8231..00000000
--- a/tests/other_errors/imported/imported.jou
+++ /dev/null
@@ -1,10 +0,0 @@
-# This file is meant to be imported, not ran directly.
-
-import "stdlib/io.jou"
-
-def add(a: int, b: int) -> int:
-    return a + b
-
-def main() -> int:
-    printf("%d", add(1, 2))
-    return 0
diff --git a/tests/other_errors/imported/cycle.jou b/tests/should_succeed/imported/cycle.jou
similarity index 100%
rename from tests/other_errors/imported/cycle.jou
rename to tests/should_succeed/imported/cycle.jou

From d05da703e069f75730ec8d852ce83ff6fae19e65 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Tue, 20 Aug 2024 22:45:34 +0800
Subject: [PATCH 25/26] revert and tmp

---
 self_hosted/create_llvm_ir.jou |  9 +--------
 self_hosted/main.jou           | 32 ++++++++++++++++++++++++--------
 2 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/self_hosted/create_llvm_ir.jou b/self_hosted/create_llvm_ir.jou
index 764a94ee..ddd0d4ff 100644
--- a/self_hosted/create_llvm_ir.jou
+++ b/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*, checkmain: bool) -> LLVMModule*:
+def create_llvm_ir(ast: AstFile*, ft: FileTypes*) -> LLVMModule*:
     module = LLVMModuleCreateWithName(ast->path)
     LLVMSetTarget(module, target.triple)
     LLVMSetDataLayout(module, target.data_layout)
@@ -874,12 +874,9 @@ def create_llvm_ir(ast: AstFile*, ft: FileTypes*, checkmain: bool) -> 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
@@ -892,9 +889,5 @@ def create_llvm_ir(ast: AstFile*, ft: FileTypes*, checkmain: bool) -> 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
diff --git a/self_hosted/main.jou b/self_hosted/main.jou
index b9aabc9d..8485fe60 100644
--- a/self_hosted/main.jou
+++ b/self_hosted/main.jou
@@ -90,6 +90,10 @@ def parse_args(argc: int, argv: byte**) -> CommandLineArgs:
 
     return result
 
+def find_file(files: FileState*, nfiles: int, path: byte*) -> FileState:
+    for i = 0; i < nfiles; i++:
+        if strcmp(files[i].ast.path, path) == 0:
+            return files[i]
 
 # C:\Users\myname\.foo-bar.jou --> "_foo_bar"
 # Result never contains "-", so you can add "-" separated suffixes without conflicts.
@@ -117,6 +121,14 @@ def get_sane_filename(path: byte*) -> byte[50]:
             name[i] = '_'
     return name
 
+
+def check_main_function(ast: AstFile*) -> bool:
+    for i = 0; i < ast->body.nstatements; i++:
+        s = &ast->body.statements[i]
+        if (s->kind == AstStatementKind::Function and strcmp(s->function.signature.name, "main") == 0):
+            return True
+    return False
+
 def check_ast_and_import_conflicts(ast: AstFile*, symbol: ExportSymbol*) -> None:
     for i = 0; i < ast->body.nstatements; i++:
         ts = &ast->body.statements[i]
@@ -210,6 +222,10 @@ class Compiler:
 
             evaluate_compile_time_if_statements_in_body(&ast.body)
 
+            if (strcmp(item.path, self->args->main_path) == 0 and check_main_function(&self->files->ast)):
+                assert item.import_location.path != NULL
+                fail(item.import_location, "imported file should not have `main` function")
+
             self->files = realloc(self->files, sizeof self->files[0] * (self->nfiles + 1))
             self->files[self->nfiles++] = FileState{ast = ast}
 
@@ -258,9 +274,6 @@ class Compiler:
                             "  %s: imported in %s, exported in %s\n",
                             exp->name, src->ast.path, dest->ast.path,
                         )
-                    if strcmp(exp->name, "main") == 0:
-                        l: Location = Location{path=src->ast.path, lineno = 0}
-                        fail(l, "imported file should not have `main` function")
                     check_ast_and_import_conflicts(&dest->ast, exp)
                     dest->typectx.add_imported_symbol(exp)
 
@@ -350,14 +363,10 @@ 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)
 
-            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)
+            module = create_llvm_ir(&self->files[i].ast, &self->files[i].typectx)
             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.
@@ -474,6 +483,13 @@ def main(argc: int, argv: byte**) -> int:
         compiler.process_imports_and_exports()
         compiler.typecheck_stage3_all_files()
 
+        mainfile = find_file(compiler.files, compiler.nfiles, args.main_path)
+        assert mainfile
+
+        if (not check_main_function(&mainfile.ast)):
+            l = Location{path=mainfile->path, lineno=0}
+            fail(l, "missing `main` function to execute the program")
+
         object_files = compiler.create_object_files()
         executable = compiler.link(object_files)
         for i = 0; object_files[i] != NULL; i++:

From 5a9779b143f30b113c0eadc949d9473497776e9a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=B0=8F=E7=99=BD=E4=BA=91?=
 <71159641+littlewhitecloud@users.noreply.github.com>
Date: Wed, 21 Aug 2024 20:05:02 +0800
Subject: [PATCH 26/26] fix and update

---
 self_hosted/main.jou | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/self_hosted/main.jou b/self_hosted/main.jou
index 8485fe60..75932da6 100644
--- a/self_hosted/main.jou
+++ b/self_hosted/main.jou
@@ -90,10 +90,11 @@ def parse_args(argc: int, argv: byte**) -> CommandLineArgs:
 
     return result
 
-def find_file(files: FileState*, nfiles: int, path: byte*) -> FileState:
+def find_file(files: FileState*, nfiles: int, path: byte*) -> FileState*:
     for i = 0; i < nfiles; i++:
         if strcmp(files[i].ast.path, path) == 0:
-            return files[i]
+            return &files[i]
+    return NULL
 
 # C:\Users\myname\.foo-bar.jou --> "_foo_bar"
 # Result never contains "-", so you can add "-" separated suffixes without conflicts.
@@ -125,7 +126,7 @@ def get_sane_filename(path: byte*) -> byte[50]:
 def check_main_function(ast: AstFile*) -> bool:
     for i = 0; i < ast->body.nstatements; i++:
         s = &ast->body.statements[i]
-        if (s->kind == AstStatementKind::Function and strcmp(s->function.signature.name, "main") == 0):
+        if s->kind == AstStatementKind::Function and strcmp(s->function.signature.name, "main") == 0:
             return True
     return False
 
@@ -222,7 +223,7 @@ class Compiler:
 
             evaluate_compile_time_if_statements_in_body(&ast.body)
 
-            if (strcmp(item.path, self->args->main_path) == 0 and check_main_function(&self->files->ast)):
+            if item.is_imported and check_main_function(&ast):
                 assert item.import_location.path != NULL
                 fail(item.import_location, "imported file should not have `main` function")
 
@@ -484,10 +485,10 @@ def main(argc: int, argv: byte**) -> int:
         compiler.typecheck_stage3_all_files()
 
         mainfile = find_file(compiler.files, compiler.nfiles, args.main_path)
-        assert mainfile
+        assert mainfile != NULL
 
-        if (not check_main_function(&mainfile.ast)):
-            l = Location{path=mainfile->path, lineno=0}
+        if not check_main_function(&mainfile->ast):
+            l = Location{path=mainfile->ast.path, lineno=0}
             fail(l, "missing `main` function to execute the program")
 
         object_files = compiler.create_object_files()