native: handle ident and integer args in exit and add arm64

vlib/v/gen/native/amd64.v

@@ -361,10 +361,40 @@ pub fn (mut g Gen) gen_print(s string) {
 	g.syscall()
 }
 
-pub fn (mut g Gen) gen_exit() {
-	// Return 0
-	g.mov(.edi, 0) // ret value
-	g.mov(.eax, 60)
+fn (mut g Gen) nsyscall_exit() int {
+	match g.pref.os {
+		.linux {
+			return 60
+		}
+		.macos {
+			return 0x2000001
+		}
+		else {
+			verror('unsupported exit syscall for this platform')
+		}
+	}
+	return 0
+}
+
+pub fn (mut g Gen) gen_amd64_exit(expr ast.Expr) {
+	// ret value
+	match expr {
+		ast.CallExpr {
+			right := expr.return_type
+			verror('native exit builtin: Unsupported call $right')
+		}
+		ast.Ident {
+			var_offset := g.get_var_offset(expr.name)
+			g.mov_var_to_reg(.edi, var_offset)
+		}
+		ast.IntegerLiteral {
+			g.mov(.edi, expr.val.int())
+		}
+		else {
+			verror('native builtin exit expects a numeric argument')
+		}
+	}
+	g.mov(.eax, g.nsyscall_exit())
 	g.syscall()
 }
 
@@ -626,7 +656,8 @@ fn (mut g Gen) fn_decl(node ast.FnDecl) {
 	g.stmts(node.stmts)
 	if is_main {
 		// println('end of main: gen exit')
-		g.gen_exit()
+		zero := ast.IntegerLiteral{}
+		g.gen_exit(zero)
 		// return
 	}
 	if !is_main {

vlib/v/gen/native/arm64.v

@@ -100,3 +100,16 @@ fn (mut g Gen) svc() {
 	g.write32(0xd4001001)
 	g.println('svc')
 }
+
+pub fn (mut g Gen) gen_arm64_exit(expr ast.Expr) {
+	match expr {
+		ast.IntegerLiteral {
+			g.mov_arm(.x16, expr.val.u64())
+		}
+		else {
+			verror('native builtin exit expects a numeric argument')
+		}
+	}
+	g.mov_arm(.x0, 0)
+	g.svc()
+}

vlib/v/gen/native/gen.v

@@ -259,6 +259,20 @@ fn (mut g Gen) for_in_stmt(node ast.ForInStmt) {
 	*/
 }
 
+pub fn (mut g Gen) gen_exit(node ast.Expr) {
+	match g.pref.arch {
+		.amd64 {
+			g.gen_amd64_exit(node)
+		}
+		.arm64 {
+			g.gen_arm64_exit(node)
+		}
+		else {
+			verror('native exit not implemented for this architecture $g.pref.arch')
+		}
+	}
+}
+
 fn (mut g Gen) stmt(node ast.Stmt) {
 	match node {
 		ast.AssignStmt {
@@ -294,7 +308,8 @@ fn (mut g Gen) stmt(node ast.Stmt) {
 		}
 		ast.Module {}
 		ast.Return {
-			g.gen_exit()
+			zero := ast.IntegerLiteral{}
+			g.gen_exit(zero)
 			g.ret()
 		}
 		ast.StructDecl {}
@@ -311,6 +326,11 @@ fn (mut g Gen) expr(node ast.Expr) {
 		ast.ArrayInit {}
 		ast.BoolLiteral {}
 		ast.CallExpr {
+			if node.name == 'exit' {
+				expr := node.args[0].expr
+				g.gen_exit(expr)
+				return
+			}
 			if node.name in ['println', 'print', 'eprintln', 'eprint'] {
 				expr := node.args[0].expr
 				g.gen_print_from_expr(expr, node.name in ['println', 'eprintln'])

vlib/v/gen/native/macho.v

@@ -101,7 +101,6 @@ pub fn (mut g Gen) generate_macho_header() {
 	if g.pref.arch == .arm64 {
 		g.gen_arm64_helloworld()
 	}
-
 }
 
 pub fn (mut g Gen) generate_macho_footer() {