cgen: fix os.args initialization, so that `const x = os.args[0]` works

vlib/os/os_test.v

@@ -7,6 +7,10 @@ const (
 	tfolder = os.join_path(os.temp_dir(), 'v', 'tests', 'os_test')
 )
 
+// os.args has to be *already initialized* with the program's argc/argv at this point
+// thus it can be used for other consts too:
+const args_at_start = os.args.clone()
+
 fn testsuite_begin() {
 	eprintln('testsuite_begin, tfolder = $tfolder')
 	os.rmdir_all(tfolder)
@@ -14,6 +18,9 @@ fn testsuite_begin() {
 	os.mkdir_all(tfolder)
 	os.chdir(tfolder)
 	assert os.is_dir(tfolder)
+	// println('args_at_start: $args_at_start')
+	assert args_at_start.len > 0
+	assert args_at_start == os.args
 }
 
 fn testsuite_end() {

vlib/v/gen/cgen.v

@@ -36,7 +36,7 @@ mut:
 	typedefs2                        strings.Builder
 	type_definitions                 strings.Builder // typedefs, defines etc (everything that goes to the top of the file)
 	definitions                      strings.Builder // typedefs, defines etc (everything that goes to the top of the file)
-	inits                            map[string]strings.Builder // contents of `void _vinit(){}`
+	inits                            map[string]strings.Builder // contents of `void _vinit/2{}`
 	cleanups                         map[string]strings.Builder // contents of `void _vcleanup(){}`
 	gowrappers                       strings.Builder // all go callsite wrappers
 	stringliterals                   strings.Builder // all string literals (they depend on tos3() beeing defined
@@ -224,7 +224,7 @@ pub fn cgen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 		// anon fn may include assert and thus this needs
 		// to be included before any test contents are written
 		if g.is_test && !tests_inited {
-			g.write_tests_main()
+			g.write_tests_definitions()
 			tests_inited = true
 		}
 		g.stmts(file.stmts)
@@ -421,7 +421,9 @@ pub fn (mut g Gen) finish() {
 	if g.pref.is_livemain || g.pref.is_liveshared {
 		g.generate_hotcode_reloader_code()
 	}
-	if !g.pref.is_test {
+	if g.pref.is_test {
+		g.gen_c_main_for_tests()
+	} else {
 		g.gen_c_main()
 	}
 }
@@ -4397,13 +4399,20 @@ fn (mut g Gen) const_decl_simple_define(name string, val string) {
 }
 
 fn (mut g Gen) const_decl_init_later(mod string, name string, val string, typ table.Type) {
-	// Initialize more complex consts in `void _vinit(){}`
+	// Initialize more complex consts in `void _vinit/2{}`
 	// (C doesn't allow init expressions that can't be resolved at compile time).
 	styp := g.typ(typ)
-	//
 	cname := '_const_$name'
 	g.definitions.writeln('$styp $cname; // inited later')
+	if cname == '_const_os__args' {
+		if g.pref.os == .windows {
+			g.inits[mod].writeln('\t_const_os__args = os__init_os_args_wide(___argc, (byteptr*)___argv);')
+		} else {
+			g.inits[mod].writeln('\t_const_os__args = os__init_os_args(___argc, (byte**)___argv);')
+		}
+	} else {
 		g.inits[mod].writeln('\t$cname = $val;')
+	}
 	if g.is_autofree {
 		if styp.starts_with('array_') {
 			g.cleanups[mod].writeln('\tarray_free(&$cname);')
@@ -4697,14 +4706,8 @@ fn (mut g Gen) write_init_function() {
 		return
 	}
 	fn_vinit_start_pos := g.out.len
-	needs_constructor := g.pref.is_shared && g.pref.os != .windows
+	// ___argv is declared as voidptr here, because that unifies the windows/unix logic
-	if needs_constructor {
+	g.writeln('void _vinit(int ___argc, voidptr ___argv) {')
-		g.writeln('__attribute__ ((constructor))')
-		g.writeln('void _vinit() {')
-		g.writeln('static bool once = false; if (once) {return;} once = true;')
-	} else {
-		g.writeln('void _vinit() {')
-	}
 	if g.is_autofree {
 		// Pre-allocate the string buffer
 		// s_str_buf_size := os.getenv('V_STRBUF_MB')
@@ -4750,6 +4753,17 @@ fn (mut g Gen) write_init_function() {
 			println(g.out.after(fn_vcleanup_start_pos))
 		}
 	}
+	needs_constructor := g.pref.is_shared && g.pref.os != .windows
+	if needs_constructor {
+		// shared libraries need a way to call _vinit/2. For that purpose,
+		// provide a constructor, ensuring that all constants are initialized just once.
+		// NB: os.args in this case will be [].
+		g.writeln('__attribute__ ((constructor))')
+		g.writeln('void _vinit_caller() {')
+		g.writeln('\tstatic bool once = false; if (once) {return;} once = true;')
+		g.writeln('\t_vinit(0,0);')
+		g.writeln('}')
+	}
 }
 
 const (

vlib/v/gen/cheaders.v

@@ -306,7 +306,7 @@ static inline bool _us64_lt(uint64_t a, int64_t b) { return a < INT64_MAX && (in
 byte* g_str_buf;
 int load_so(byteptr);
 void reload_so();
-void _vinit();
+void _vinit(int ___argc, voidptr ___argv);
 void _vcleanup();
 #define sigaction_size sizeof(sigaction);
 #define _ARR_LEN(a) ( (sizeof(a)) / (sizeof(a[0])) )

vlib/v/gen/cmain.v

@@ -49,6 +49,12 @@ fn (mut g Gen) gen_c_main_function_header() {
 			}
 			// GUI application
 			g.writeln('int WINAPI wWinMain(HINSTANCE instance, HINSTANCE prev_instance, LPWSTR cmd_line, int show_cmd){')
+			g.writeln('\tLPWSTR full_cmd_line = GetCommandLineW(); // NB: do not use cmd_line')
+			g.writeln('\ttypedef LPWSTR*(WINAPI *cmd_line_to_argv)(LPCWSTR, int*);')
+			g.writeln('\tHMODULE shell32_module = LoadLibrary(L"shell32.dll");')
+			g.writeln('\tcmd_line_to_argv CommandLineToArgvW = (cmd_line_to_argv)GetProcAddress(shell32_module, "CommandLineToArgvW");')
+			g.writeln('\tint ___argc;')
+			g.writeln('\twchar_t** ___argv = CommandLineToArgvW(full_cmd_line, &___argc);')
 		} else {
 			// Console application
 			g.writeln('int wmain(int ___argc, wchar_t* ___argv[], wchar_t* ___envp[]){')
@@ -60,30 +66,12 @@ fn (mut g Gen) gen_c_main_function_header() {
 
 fn (mut g Gen) gen_c_main_header() {
 	g.gen_c_main_function_header()
-	if g.pref.os == .windows && g.is_gui_app() {
+	g.writeln('\t_vinit(___argc, (voidptr)___argv);')
-		g.writeln('\tLPWSTR full_cmd_line = GetCommandLineW(); // NB: do not use cmd_line')
-		g.writeln('\ttypedef LPWSTR*(WINAPI *cmd_line_to_argv)(LPCWSTR, int*);')
-		g.writeln('\tHMODULE shell32_module = LoadLibrary(L"shell32.dll");')
-		g.writeln('\tcmd_line_to_argv CommandLineToArgvW = (cmd_line_to_argv)GetProcAddress(shell32_module, "CommandLineToArgvW");')
-		g.writeln('\tint ___argc;')
-		g.writeln('\twchar_t** ___argv = CommandLineToArgvW(full_cmd_line, &___argc);')
-	}
-	g.writeln('\t_vinit();')
 	if g.pref.is_prof {
 		g.writeln('')
 		g.writeln('\tatexit(vprint_profile_stats);')
 		g.writeln('')
 	}
-	if g.is_importing_os() {
-		if g.is_autofree {
-			g.writeln('free(_const_os__args.data); // empty, inited in _vinit()')
-		}
-		if g.pref.os == .windows {
-			g.writeln('\t_const_os__args = os__init_os_args_wide(___argc, ___argv);')
-		} else {
-			g.writeln('\t_const_os__args = os__init_os_args(___argc, (byteptr*)___argv);')
-		}
-	}
 	if g.pref.is_livemain {
 		g.generate_hotcode_reloading_main_caller()
 	}
@@ -123,7 +111,7 @@ void (_vsokol_cleanup_userdata_cb)(void* user_data) {
 sapp_desc sokol_main(int argc, char* argv[]) {
 	(void)argc; (void)argv;
 
-	_vinit();
+	_vinit(argc, (voidptr)argv);
 	main__main();
 ')
 	if g.is_autofree {
@@ -142,21 +130,24 @@ sapp_desc sokol_main(int argc, char* argv[]) {
 	g.writeln('}')
 }
 
-pub fn (mut g Gen) write_tests_main() {
+pub fn (mut g Gen) write_tests_definitions() {
 	g.includes.writeln('#include <setjmp.h> // write_tests_main')
 	g.definitions.writeln('int g_test_oks = 0;')
 	g.definitions.writeln('int g_test_fails = 0;')
 	g.definitions.writeln('jmp_buf g_jump_buffer;')
+}
+
+pub fn (mut g Gen) gen_c_main_for_tests() {
 	main_fn_start_pos := g.out.len
-	g.gen_c_main_function_header()
-	g.writeln('\t_vinit();')
 	g.writeln('')
+	g.gen_c_main_function_header()
+	g.writeln('\t_vinit(___argc, (voidptr)___argv);')
 	all_tfuncs := g.get_all_test_function_names()
 	if g.pref.is_stats {
 		g.writeln('\tmain__BenchedTests bt = main__start_testing($all_tfuncs.len, _SLIT("$g.pref.path"));')
 	}
-	for t in all_tfuncs {
 	g.writeln('')
+	for t in all_tfuncs {
 		if g.pref.is_stats {
 			g.writeln('\tmain__BenchedTests_testing_step_start(&bt, _SLIT("$t"));')
 		}
@@ -169,7 +160,6 @@ pub fn (mut g Gen) write_tests_main() {
 	if g.pref.is_stats {
 		g.writeln('\tmain__BenchedTests_end_testing(&bt);')
 	}
-	g.writeln('')
 	if g.is_autofree {
 		g.writeln('\t_vcleanup();')
 	}