builder: module caching fixes

cmd/v/v.v

@@ -165,8 +165,8 @@ fn parse_args(args []string) (&pref.Preferences, string) {
 			'-showcc' {
 				res.show_cc = true
 			}
-			'-cache' {
-				res.is_cache = true
+			'-usecache' {
+				res.use_cache = true
 			}
 			'-keepc' {
 				res.keep_c = true

vlib/v/builder/cc.v

@@ -215,7 +215,7 @@ fn (mut v Builder) cc() {
 	mut libs := '' // builtin.o os.o http.o etc
 	if v.pref.build_mode == .build_module {
 		a << '-c'
-	} else if v.pref.is_cache {
+	} else if v.pref.use_cache {
 		/*
 		QTODO
 		builtin_o_path := os.join_path(pref.default_module_path, 'cache', 'vlib', 'builtin.o')
@@ -305,13 +305,18 @@ fn (mut v Builder) cc() {
 	// add all flags (-I -l -L etc) not .o files
 	a << cflags.c_options_without_object_files()
 	a << libs
-	if v.pref.is_cache {
-		cached_files := [ 'builtin.o', 'math.o']
-		for cfile in cached_files {
-			ofile := os.join_path(pref.default_module_path, 'cache', 'vlib', cfile)
-			if os.exists(ofile) {
-				a << ofile
+	if v.pref.use_cache {
+		//vexe := pref.vexe_path()
+
+		cached_modules:= [ 'builtin', 'os' ]//, 'math']
+		for cfile in cached_modules{
+			ofile := os.join_path(pref.default_module_path, 'cache', 'vlib', cfile + '.o')
+			if !os.exists(ofile) {
+				println('${cfile}.o is missing. Building...')
+				println('$vexe build-module vlib/$cfile')
+				os.system('$vexe build-module vlib/$cfile')
 			}
+			a << ofile
 		}
 		if !is_cc_tcc {
 			$if linux {

vlib/v/gen/fn.v

@@ -71,7 +71,7 @@ fn (mut g Gen) gen_fn_decl(it ast.FnDecl) {
 	*/
 	//
 	g.fn_args(it.args, it.is_variadic)
-	if it.no_body || (g.pref.is_cache && it.is_builtin) {
+	if it.no_body || (g.pref.use_cache && it.is_builtin) {
 		// Just a function header.
 		// Builtin function bodies are defined in builtin.o
 		g.definitions.writeln(');')
@@ -104,7 +104,7 @@ fn (mut g Gen) gen_fn_decl(it ast.FnDecl) {
 	}
 	// Profiling mode? Start counting at the beginning of the function (save current time).
 	if g.pref.is_prof {
-	    g.profile_fn( it.name, is_main )
+		g.profile_fn(it.name, is_main)
 	}
 	g.stmts(it.stmts)
 	// ////////////

vlib/v/pref/pref.v

@@ -44,7 +44,7 @@ pub mut:
 	show_cc             bool // -showcc, print cc command
 	// NB: passing -cg instead of -g will set is_vlines to false and is_g to true, thus making v generate cleaner C files,
 	// which are sometimes easier to debug / inspect manually than the .tmp.c files by plain -g (when/if v line number generation breaks).
-	is_cache            bool // turns on v usage of the module cache to speed up compilation.
+	use_cache            bool // turns on v usage of the module cache to speed up compilation.
 	is_stats            bool // `v -stats file_test.v` will produce more detailed statistics for the tests that were run
 	no_auto_free        bool // `v -nofree` disable automatic `free()` insertion for better performance in some applications  (e.g. compilers)
 	// TODO Convert this into a []string