From c62446b2abebb30193aedccb22a613e45cc32b4a Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Tue, 21 Apr 2026 15:25:21 +0300
Subject: [PATCH] builder: fix hot reload on windows (fixes #3548)

---
 vlib/sokol/c/declaration.c.v  | 24 ++++++++++++++++++++----
 vlib/v/builder/msvc_windows.v |  3 +++
 vlib/v/gen/c/live.v           | 13 ++++++++++++-
 vlib/v/live/live_test.v       | 27 +++++++++++++++++++++++++++
 vlib/v/pref/pref.v            |  2 ++
 5 files changed, 64 insertions(+), 5 deletions(-)

diff --git a/vlib/sokol/c/declaration.c.v b/vlib/sokol/c/declaration.c.v
index f7b5a0d59..d9dea950d 100644
--- a/vlib/sokol/c/declaration.c.v
+++ b/vlib/sokol/c/declaration.c.v
@@ -29,6 +29,14 @@ $if sokol_wayland ? {
 
 $if windows {
 	#flag windows -lopengl32
+	$if msvc {
+		$if livemain ? {
+			#define SOKOL_DLL
+		}
+		$if sharedlive ? {
+			#define SOKOL_DLL
+		}
+	}
 }
 
 // Note that -lm is needed *only* for sokol_gl.h's usage of sqrtf(),
@@ -112,6 +120,8 @@ $if !no_sokol_app ? {
 			// The live-reload dylib should reuse the host app's sokol_app symbols on macOS.
 			#define SOKOL_APP_IMPL
 		}
+	} $else $if windows && msvc && sharedlive ? {
+		// The live-reload DLL should call the host executable's sokol_app symbols.
 	} $else {
 		#define SOKOL_APP_IMPL
 	}
@@ -120,13 +130,19 @@ $if !no_sokol_app ? {
 	#include "sokol_app.h"
 }
 
-@[use_once]
-#define SOKOL_GFX_IMPL
+$if windows && msvc && sharedlive ? {
+} $else {
+	@[use_once]
+	#define SOKOL_GFX_IMPL
+}
 #define SOKOL_NO_DEPRECATED
 #include "sokol_gfx.h"
 
-@[use_once]
-#define SOKOL_IMPL
+$if windows && msvc && sharedlive ? {
+} $else {
+	@[use_once]
+	#define SOKOL_IMPL
+}
 #include "util/sokol_gl.h"
 
 #include "sokol_v.post.h"
diff --git a/vlib/v/builder/msvc_windows.v b/vlib/v/builder/msvc_windows.v
index de6a67031..5009fd996 100644
--- a/vlib/v/builder/msvc_windows.v
+++ b/vlib/v/builder/msvc_windows.v
@@ -357,6 +357,9 @@ pub fn (mut v Builder) cc_msvc() {
 
 	a << '/nologo' // NOTE: /NOLOGO is explicitly not recognised!
 	a << '/OUT:${os.quoted_path(v.pref.out_name)}'
+	if v.pref.is_livemain {
+		a << '/IMPLIB:${os.quoted_path(v.pref.out_name[..v.pref.out_name.len - 4] + '.lib')}'
+	}
 	a << r.library_paths()
 	if !all_cflags.contains('/DEBUG') {
 		// only use /DEBUG, if the user *did not* provide its own:
diff --git a/vlib/v/gen/c/live.v b/vlib/v/gen/c/live.v
index 339a7f75a..3682e542d 100644
--- a/vlib/v/gen/c/live.v
+++ b/vlib/v/gen/c/live.v
@@ -121,7 +121,18 @@ fn (mut g Gen) generate_hotcode_reloading_main_caller() {
 	ccpath := util.cescaped_path(g.pref.ccompiler)
 	ccompiler := '-cc ${ccpath}'
 	so_debug_flag := if g.pref.is_debug { '-cg' } else { '' }
-	vopts := '${ccompiler} ${so_debug_flag} -sharedlive -shared'
+	mut vopts := '${ccompiler} ${so_debug_flag} -sharedlive -shared'
+	if g.pref.os == .windows && g.is_cc_msvc && 'sokol' in g.table.imports {
+		mut import_lib_path := g.pref.out_name
+		ext := os.file_ext(import_lib_path)
+		if ext != '' {
+			import_lib_path = import_lib_path[..import_lib_path.len - ext.len] + '.lib'
+		} else {
+			import_lib_path += '.lib'
+		}
+		escaped_import_lib_path := util.cescaped_path(os.abs_path(import_lib_path))
+		vopts += " -ldflags \\\"${escaped_import_lib_path}\\\""
+	}
 
 	g.writeln('\t\t// start background reloading thread')
 	g.writeln('\t\tvoid* live_fn_mutex_addr = v_live_fn_mutex_ptr();')
diff --git a/vlib/v/live/live_test.v b/vlib/v/live/live_test.v
index 18fd809fb..d61a8fa84 100644
--- a/vlib/v/live/live_test.v
+++ b/vlib/v/live/live_test.v
@@ -188,6 +188,14 @@ fn run_in_background(cmd string) {
 	log.warn('the live program should be running in the background now')
 }
 
+fn must_exec_cmd(cmd string) {
+	res := os.execute(cmd)
+	if res.exit_code == 0 {
+		return
+	}
+	panic('command failed: ${cmd}\n${res.output}')
+}
+
 fn test_live_program_can_be_compiled() {
 	setup_cycles_environment()
 	compile_cmd := '${os.quoted_path(vexe)} -cg -keepc -nocolor -live -o ${os.quoted_path(genexe_file)} ${os.quoted_path(main_source_file)}'
@@ -226,3 +234,22 @@ fn test_live_program_can_be_changed_4() {
 	change_source('STOP')
 	assert true
 }
+
+fn test_live_windows_sokol_sharedlive_build_uses_host_import_lib() {
+	$if !windows || !msvc {
+		return
+	}
+	tmp_dir := os.join_path(os.vtmp_dir(), 'live_windows_sokol_compile')
+	os.mkdir_all(tmp_dir) or { panic(err) }
+	defer {
+		os.rmdir_all(tmp_dir) or {}
+	}
+	source := os.join_path(@VEXEROOT, 'examples', 'sokol', 'drawing.v')
+	exe_path := os.join_path(tmp_dir, 'drawing_live.exe')
+	lib_path := exe_path[..exe_path.len - 4] + '.lib'
+	dll_path := os.join_path(tmp_dir, 'drawing_live_shared.dll')
+	must_exec_cmd('${os.quoted_path(vexe)} -nocolor -cc msvc -live -o ${os.quoted_path(exe_path)} ${os.quoted_path(source)}')
+	assert os.exists(lib_path)
+	must_exec_cmd('${os.quoted_path(vexe)} -nocolor -cc msvc -sharedlive -shared -ldflags ${os.quoted_path(lib_path)} -o ${os.quoted_path(dll_path)} ${os.quoted_path(source)}')
+	assert os.exists(dll_path)
+}
diff --git a/vlib/v/pref/pref.v b/vlib/v/pref/pref.v
index 35cb36845..a00c57e83 100644
--- a/vlib/v/pref/pref.v
+++ b/vlib/v/pref/pref.v
@@ -682,6 +682,8 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 			}
 			'-live' {
 				res.is_livemain = true
+				res.compile_defines << 'livemain'
+				res.compile_defines_all << 'livemain'
 			}
 			'-sharedlive' {
 				res.is_liveshared = true
-- 
2.39.5