compiler: move msvc compiler to -cc flag instead of -os (#2338)

* move msvc to -cc flag instead of -os

* undo unrelated change

* do first build without msvc

* remvove flags temp

* fix comment

vlib/compiler/cc.v

@@ -48,7 +48,7 @@ fn (v mut V) cc() {
 		}
 	}
 	$if windows {
-		if v.os == .msvc {
+		if v.pref.ccompiler == 'msvc' {
 			v.cc_msvc()
 			return
 		}
@@ -119,7 +119,7 @@ fn (v mut V) cc() {
 		a << ' -rdynamic ' // needed for nicer symbolic backtraces
 	}
 
-	if v.os != .msvc && v.os != .freebsd {
+	if v.pref.ccompiler != 'msvc' && v.os != .freebsd {
 		a << '-Werror=implicit-function-declaration'
 	}
 
@@ -314,7 +314,11 @@ fn (c mut V) cc_windows_cross() {
 	mut args := '-o $c.out_name -w -L. '
 	cflags := c.get_os_cflags()
 	// -I flags
-	args += cflags.c_options_before_target()
+	args += if c.pref.ccompiler == 'msvc' {
+		cflags.c_options_before_target_msvc()
+	} else {
+		cflags.c_options_before_target()
+	}
 	mut libs := ''
 	if c.pref.build_mode == .default_mode {
 		libs = '"$v_modules_path/vlib/builtin.o"'
@@ -327,7 +331,11 @@ fn (c mut V) cc_windows_cross() {
 		}
 	}
 	args += ' $c.out_name_c '
-	args += cflags.c_options_after_target()
+	args += if c.pref.ccompiler == 'msvc' {
+		cflags.c_options_after_target_msvc()
+	} else {
+		cflags.c_options_after_target()
+	}
 	println('Cross compiling for Windows...')
 	winroot := '$v_modules_path/winroot'
 	if !os.dir_exists(winroot) {
@@ -372,7 +380,7 @@ fn (c &V) build_thirdparty_obj_files() {
 	for flag in c.get_os_cflags() {
 		if flag.value.ends_with('.o') {			
 			rest_of_module_flags := c.get_rest_of_module_cflags( flag )
-			if c.os == .msvc {
+			if c.pref.ccompiler == 'msvc' {
 				build_thirdparty_obj_file_with_msvc(flag.value, rest_of_module_flags)
 			}
 			else {

vlib/compiler/cflags.v

@@ -26,7 +26,7 @@ fn (v &V) get_os_cflags() []CFlag {
 		|| (flag.os == 'linux' && v.os == .linux)
 		|| (flag.os == 'darwin' && v.os == .mac)
 		|| (flag.os == 'freebsd' && v.os == .freebsd)
-		|| (flag.os == 'windows' && (v.os == .windows || v.os == .msvc)) {
+		|| (flag.os == 'windows' && v.os == .windows) {
 			flags << flag
 		}
 	}
@@ -140,10 +140,10 @@ fn (table mut Table) parse_cflag(cflag string, mod string) {
 }
 
 //TODO: implement msvc specific c_options_before_target and c_options_after_target ...
+fn (cflags []CFlag) c_options_before_target_msvc() string { return '' }
+fn (cflags []CFlag) c_options_after_target_msvc() string { return '' }
+
 fn (cflags []CFlag) c_options_before_target() string {	
-	$if msvc {
-		return ''
-	}
 	// -I flags, optimization flags and so on
 	mut args:=[]string
 	for flag in cflags {
@@ -155,9 +155,6 @@ fn (cflags []CFlag) c_options_before_target() string {
 }
 
 fn (cflags []CFlag) c_options_after_target() string {
-	$if msvc {
-		return ''
-	}
 	// -l flags (libs)
 	mut args:=[]string
 	for flag in cflags {

vlib/compiler/fn.v

@@ -326,7 +326,7 @@ fn (p mut Parser) fn_decl() {
 			p.error_with_token_index('fn main must have no arguments and no return values', f.fn_name_token_idx)
 		}
 	}
-	dll_export_linkage := if p.os == .msvc && p.attr == 'live' && p.pref.is_so {
+	dll_export_linkage := if p.pref.ccompiler == 'msvc' && p.attr == 'live' && p.pref.is_so {
 		'__declspec(dllexport) '
 	} else if p.attr == 'inline' {
 		'static inline '
@@ -590,7 +590,7 @@ fn (p mut Parser) async_fn_call(f Fn, method_ph int, receiver_var, receiver_type
 	// Create thread object
 	tmp_nr := p.get_tmp_counter()
 	thread_name = '_thread$tmp_nr'
-	if p.os != .windows && p.os != .msvc {
+	if p.os != .windows {
 		p.genln('pthread_t $thread_name;')
 	}
 	tmp2 := p.get_tmp()
@@ -599,7 +599,7 @@ fn (p mut Parser) async_fn_call(f Fn, method_ph int, receiver_var, receiver_type
 		parg = ' $tmp_struct'
 	}
 	// Call the wrapper
-	if p.os == .windows || p.os == .msvc {
+	if p.os == .windows {
 		p.genln(' CreateThread(0,0, $wrapper_name, $parg, 0,0);')
 	}
 	else {

vlib/compiler/gen_c.v

@@ -75,7 +75,7 @@ fn (p mut Parser) gen_var_decl(name string, is_static bool) string {
 }
 
 fn (p mut Parser) gen_fn_decl(f Fn, typ, str_args string) {
-	dll_export_linkage := if p.os == .msvc && p.attr == 'live' && p.pref.is_so {
+	dll_export_linkage := if p.pref.ccompiler == 'msvc' && p.attr == 'live' && p.pref.is_so {
 		'__declspec(dllexport) '
 	} else if p.attr == 'inline' {
 		'static inline '

vlib/compiler/live.v

@@ -19,7 +19,7 @@ fn (v &V) generate_hotcode_reloading_compiler_flags() []string {
 
 fn (v &V) generate_hotcode_reloading_declarations() {
 	mut cgen := v.cgen
-	if v.os != .windows && v.os != .msvc {
+	if v.os != .windows {
 		if v.pref.is_so {
 			cgen.genln('pthread_mutex_t live_fn_mutex;')
 		}
@@ -42,7 +42,7 @@ fn (v &V) generate_hotcode_reloading_main_caller() {
 	mut cgen := v.cgen
 	cgen.genln('')
 	file_base := os.filename(v.dir).replace('.v', '')
-	if !(v.os == .windows || v.os == .msvc) {
+	if v.os != .windows {
 		// unix:
 		so_name := file_base + '.so'
 		cgen.genln('  char *live_library_name = "$so_name";')
@@ -51,7 +51,7 @@ fn (v &V) generate_hotcode_reloading_main_caller() {
 		cgen.genln('  pthread_create(&_thread_so , NULL, &reload_so, live_library_name);')
 	} else {
 		// windows:
-		so_name := file_base + if v.os == .msvc {'.dll'} else {'.so'}
+		so_name := file_base + if v.pref.ccompiler == 'msvc' {'.dll'} else {'.so'}
 		cgen.genln('  char *live_library_name = "$so_name";')
 		cgen.genln('  live_fn_mutex = CreateMutexA(0, 0, 0);')
 		cgen.genln('  load_so(live_library_name);')
@@ -78,8 +78,8 @@ fn (v &V) generate_hot_reload_code() {
 		}
 		
 		mut msvc := ''
-		if v.os == .msvc {
-			msvc = '-os msvc'
+		if v.pref.ccompiler == 'msvc' {
+			msvc = '-cc msvc'
 		}
 		
 		so_debug_flag := if v.pref.is_debug { '-g' } else { '' }		
@@ -104,7 +104,7 @@ void lfnmutex_print(char *s){
 }
 ')
 
-		if v.os != .windows && v.os != .msvc {
+		if v.os != .windows {
 			cgen.genln('
 #include <dlfcn.h>
 void* live_lib=0;

vlib/compiler/msvc.v

@@ -396,8 +396,8 @@ fn build_thirdparty_obj_file_with_msvc(path string, moduleflags []CFlag) {
 
 	//println('cfiles: $cfiles')
 
-	btarget := moduleflags.c_options_before_target()
-	atarget := moduleflags.c_options_after_target()
+	btarget := moduleflags.c_options_before_target_msvc()
+	atarget := moduleflags.c_options_after_target_msvc()
 	cmd := '""$msvc.full_cl_exe_path" /volatile:ms /Zi /DNDEBUG $include_string /c $btarget $cfiles $atarget /Fo"$obj_path""'
 	//NB: the quotes above ARE balanced.
 	println('thirdparty cmd line: $cmd')

vlib/compiler/vhelp.v

@@ -26,7 +26,7 @@ const (
    you don\'t have to repeat them.
 
    You can set it like this: `export VFLAGS="-cc clang -debug"` on *nix,
-   `set VFLAGS=-os msvc` on Windows.
+   `set VFLAGS=-cc msvc` on Windows.
 
 Options/commands:
   -h, help          Display this information.