Prevent people on platforms that arent 'windows' from being able to build with msvc

compiler/main.v

@@ -210,6 +210,11 @@ fn main() {
 }
 
 fn (v mut V) compile() {
+	// Emily: Stop people on linux from being able to build with msvc
+	if os.user_os() != 'windows' && v.os == .msvc {
+		panic('Cannot build with msvc on ${os.user_os()}')
+	}
+
 	mut cgen := v.cgen
 	cgen.genln('// Generated by V')
 	v.add_v_files_to_compile()
@@ -754,6 +759,7 @@ fn (v mut V) cc() {
 			return
 		}
 	}
+	
 	linux_host := os.user_os() == 'linux'
 	v.log('cc() isprod=$v.pref.is_prod outname=$v.out_name')
 	mut a := [v.pref.cflags, '-std=gnu11', '-w'] // arguments for the C compiler

compiler/msvc.v

@@ -30,6 +30,7 @@ const (
 
 // Given a root key look for one of the subkeys in 'versions' and get the path 
 fn find_windows_kit_internal(key RegKey, versions []string) ?string {
+	$if windows {
 		for version in versions {
 			required_bytes := 0 // TODO mut
 			result := C.RegQueryValueExW(key, version.to_wide(), 0, 0, 0, &required_bytes)
@@ -61,6 +62,7 @@ fn find_windows_kit_internal(key RegKey, versions []string) ?string {
 
 			return string_from_wide(value)
 		}
+	}
 	return error('windows kit not found')
 }
 
@@ -75,6 +77,7 @@ struct WindowsKit {
 
 // Try and find the root key for installed windows kits
 fn find_windows_kit_root() ?WindowsKit {
+	$if windows {
 		root_key := RegKey(0)
 		rc := C.RegOpenKeyExA(
 			HKEY_LOCAL_MACHINE, 'SOFTWARE\\Microsoft\\Windows Kits\\Installed Roots', 0, KEY_QUERY_VALUE | KEY_WOW64_32KEY | KEY_ENUMERATE_SUB_KEYS, &root_key)
@@ -120,6 +123,8 @@ fn find_windows_kit_root() ?WindowsKit {
 			shared_include_path: kit_include_highest + '\\shared'
 		}
 	}
+	return error('Host OS does not support funding a windows kit')
+}
 
 struct VsInstallation {
 	include_path string
@@ -128,6 +133,9 @@ struct VsInstallation {
 }
 
 fn find_vs() ?VsInstallation {
+	$if !windows {
+		return error('Host OS does not support finding a Vs installation')
+	}
 	// Emily:
 	// VSWhere is guaranteed to be installed at this location now
 	// If its not there then end user needs to update their visual studio 
@@ -192,23 +200,28 @@ fn find_msvc() ?MsvcResult {
 		}
 	}
 	$else {
-		panic('Cannot find msvc on this platform')
+		panic('Cannot find msvc on this OS')
 	}
 }
 
 pub fn (v mut V) cc_msvc() { 
 	r := find_msvc() or {
-		println('Could not find MSVC')
-		
 		// TODO: code reuse
 		if !v.pref.is_debug && v.out_name_c != 'v.c' && v.out_name_c != 'v_macos.c' {
 			os.rm('.$v.out_name_c')
 		}
-		return
+		panic('Cannot find MSVC on this OS.')
 	}
 
+	out_name_obj := v.out_name_c + '.obj'
+
 	// Default arguments
-	mut a := ['-w', '/volatile:ms', '/D_UNICODE', '/DUNICODE']
+
+	// volatile:ms enables atomic volatile (gcc _Atomic)
+	// -w: no warnings
+	// 2 unicode defines
+	// /Fo sets the object file name - needed so we can clean up after ourselves properly
+	mut a := ['-w', '/volatile:ms', '/D_UNICODE', '/DUNICODE', '/Fo$out_name_obj']
 
 	if v.pref.is_prod {
 		a << '/O2'
@@ -219,7 +232,6 @@ pub fn (v mut V) cc_msvc() {
 	}
 
 	if v.pref.is_so {
-		// Dont think we have to do anything for this
 		if !v.out_name.ends_with('.dll') {
 			v.out_name = v.out_name + '.dll'
 		}
@@ -258,6 +270,9 @@ pub fn (v mut V) cc_msvc() {
 	//a << '"$TmpPath/$v.out_name_c"'
 	a << '".$v.out_name_c"'
 
+	// Emily:
+	// Not all of these are needed (but the compiler should discard them if they are not used)
+	// these are the defaults used by msbuild and visual studio
 	mut real_libs :=  [
 		'kernel32.lib',
 		'user32.lib',
@@ -287,6 +302,10 @@ pub fn (v mut V) cc_msvc() {
 		if f.starts_with('-l') {
 			lib_base := f.right(2).trim_space()
 
+			if lib_base.ends_with('.dll') {
+				panic('MSVC cannot link against a dll (`#flag -l $lib_base`)')
+			}
+
 			// MSVC has no method of linking against a .dll
 			// TODO: we should look for .defs aswell
 			lib_lib := lib_base + '.lib'
@@ -307,11 +326,9 @@ pub fn (v mut V) cc_msvc() {
 	// Include the base paths
 	a << '-I "$r.ucrt_include_path" -I "$r.vs_include_path" -I "$r.um_include_path" -I "$r.shared_include_path"'
 
-	// Msvc also doesnt have atomic
-	// TODO: dont rely on gcc's _Atomic semantics!
 	a << other_flags
 
-	// TODO: libs will need to be actually handled properly
+	// Libs are passed to cl.exe which passes them to the linker
 	a << real_libs.join(' ')
 
 	a << '/link'
@@ -350,6 +367,7 @@ pub fn (v mut V) cc_msvc() {
 
 	if !v.pref.is_debug && v.out_name_c != 'v.c' && v.out_name_c != 'v_macos.c' {
 		os.rm('.$v.out_name_c')
+		os.rm('$out_name_obj')
 	}
 
 }

compiler/msvc_nix.v

@@ -1,8 +0,0 @@
-module main
-
-fn (v mut V) cc_msvc() { 
-}
-
-fn build_thirdparty_obj_file_with_msvc(flag string) {
- 
-}