From 587075176908d44a9a524e788e7daa86a736a132 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Sat, 12 Jun 2021 22:15:08 +0300
Subject: [PATCH] v.gen.c: use the __V_architecture macro in
 v.pref.get_host_arch()

---
 vlib/v/ast/types.v |  2 +-
 vlib/v/pref/pref.v | 23 ++++++++++-------------
 2 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/vlib/v/ast/types.v b/vlib/v/ast/types.v
index 159cde105e..53b7826e3b 100644
--- a/vlib/v/ast/types.v
+++ b/vlib/v/ast/types.v
@@ -51,7 +51,7 @@ pub fn pref_arch_to_table_language(pref_arch pref.Arch) Language {
 		.i386 {
 			Language.i386
 		}
-		._auto {
+		._auto, ._max {
 			Language.v
 		}
 	}
diff --git a/vlib/v/pref/pref.v b/vlib/v/pref/pref.v
index 1a9f0fd3c4..1ce329a4f3 100644
--- a/vlib/v/pref/pref.v
+++ b/vlib/v/pref/pref.v
@@ -67,6 +67,7 @@ pub enum Arch {
 	rv64 // 64-bit risc-v
 	rv32 // 32-bit risc-v
 	i386
+	_max
 }
 
 const (
@@ -754,20 +755,16 @@ pub fn cc_from_string(cc_str string) CompilerType {
 }
 
 pub fn get_host_arch() Arch {
-	$if amd64 {
-		return .amd64
+	// NB: we can not use `$if arch` here, because V skips cgen for the non
+	// current comptime branches by default, so there is a bootstrapping
+	// problem => the __V_architecture macro is used to resolve it.
+	// TODO: think about how to solve it for non C backends, perhaps we
+	// need a comptime `$if native {` too, and/or a mechanism to always
+	// generate all branches for specific functions?
+	if C.__V_architecture <= int(Arch._auto) || C.__V_architecture >= int(Arch._max) {
+		panic('unknown host CPU architecture')
 	}
-	// $if i386 {
-	// 	return .amd64
-	// }
-	// $if arm64 { // requires new vc
-	$if aarch64 {
-		return .arm64
-	}
-	// $if arm32 {
-	// 	return .arm32
-	// }
-	panic('unknown host OS')
+	return Arch(C.__V_architecture)
 }
 
 fn parse_define(mut prefs Preferences, define string) {