From 9020fc2ffea145ed1469d73fb8d363e74b595d4a Mon Sep 17 00:00:00 2001
From: Catherine <whitequark@whitequark.org>
Date: Wed, 5 Aug 2026 15:15:16 +0000
Subject: [PATCH] Accept UTF-8 filenames and terminal I/O on Windows.

---
 CMakeLists.txt   |  2 +-
 kernel/driver.cc | 24 ++++++++++++++++++++++++
 kernel/io.cc     | 17 ++++++++++-------
 kernel/yosys.cc  | 22 ++++++++++------------
 4 files changed, 45 insertions(+), 20 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index bccf29049..3771394b2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -426,7 +426,7 @@ if (NOT YOSYS_BUILD_PYTHON_ONLY)
 	yosys_link_components(yosys PRIVATE ${driver_components})
 	set_property(TARGET yosys PROPERTY ENABLE_EXPORTS ON)
 	if (MINGW)
-		target_link_options(yosys PRIVATE LINKER:--export-all-symbols)
+		target_link_options(yosys PRIVATE -municode LINKER:--export-all-symbols)
 		set_target_properties(yosys PROPERTIES
 			# Final name: `yosys.exe.a` (linked to explicitly)
 			IMPORT_PREFIX ""
diff --git a/kernel/driver.cc b/kernel/driver.cc
index 2a4ad1295..c67630f10 100644
--- a/kernel/driver.cc
+++ b/kernel/driver.cc
@@ -48,6 +48,7 @@ namespace py = pybind11;
 #include <string.h>
 #include <limits.h>
 #include <errno.h>
+#include <fcntl.h>
 #ifndef __STDC_FORMAT_MACROS
 #  define __STDC_FORMAT_MACROS
 #endif
@@ -112,8 +113,31 @@ namespace Yosys {
 };
 #endif
 
+#ifdef _WIN32
+int wmain(int argc, wchar_t **wargv)
+{
+	// Configure ASCII functions like fopen() to use UTF-8 filenames.
+	// See https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/setlocale-wsetlocale?view=msvc-170#utf-8-support
+#ifdef _UCRT
+	setlocale(LC_ALL, ".UTF-8");
+#endif
+	// Configure the Win32 console to use UTF-8.
+	SetConsoleCP(CP_UTF8);
+	SetConsoleOutputCP(CP_UTF8);
+
+	std::vector<char*> uargs;
+	for (int i = 0; i < argc; i++) {
+		int usize = WideCharToMultiByte(CP_UTF8, 0, wargv[i], -1, NULL, 0, NULL, NULL);
+		char *uarg = (char *)malloc(usize);
+		WideCharToMultiByte(CP_UTF8, 0, wargv[i], -1, uarg, usize, NULL, NULL);
+		uargs.push_back(uarg);
+	}
+	uargs.push_back(NULL);
+	char **argv = uargs.data();
+#else
 int main(int argc, char **argv)
 {
+#endif
 	auto wall_clock_start = std::chrono::steady_clock::now();
 	std::string frontend_command = "auto";
 	std::string backend_command = "auto";
diff --git a/kernel/io.cc b/kernel/io.cc
index a82f88a62..1d0566930 100644
--- a/kernel/io.cc
+++ b/kernel/io.cc
@@ -155,13 +155,16 @@ std::string get_base_tmpdir()
 	}
 
 #if defined(_WIN32)
-	char longpath[MAX_PATH + 1];
-	char shortpath[MAX_PATH + 1];
-	if (!GetTempPathA(MAX_PATH+1, longpath))
-		log_error("GetTempPath() failed.\n");
-	if (!GetShortPathNameA(longpath, shortpath, MAX_PATH + 1))
-		log_error("GetShortPathName() failed.\n");
-	tmpdir += shortpath;
+	std::wstring wtmppath(4096, L'\0');
+	// typically returns a 8.3 path, but this can be disabled via registry
+	if (!GetTempPathW(wtmppath.size(), wtmppath.data()))
+		log_error("GetTempPathW() failed.\n");
+	wtmppath.resize(wtmppath.find(L'\0'));
+	std::string utmppath;
+	utmppath.resize(WideCharToMultiByte(CP_UTF8, 0, wtmppath.data(), wtmppath.size(), NULL, 0, NULL, NULL));
+	if (WideCharToMultiByte(CP_UTF8, 0, wtmppath.data(), wtmppath.size(), utmppath.data(), utmppath.size(), NULL, NULL) == 0)
+		log_error("WideCharToMultiByte() failed.\n");
+	tmpdir += utmppath;
 #else
 	char * var = std::getenv("TMPDIR");
 	if (var && strlen(var)!=0) {
diff --git a/kernel/yosys.cc b/kernel/yosys.cc
index d47610800..c2574497d 100644
--- a/kernel/yosys.cc
+++ b/kernel/yosys.cc
@@ -537,18 +537,16 @@ std::string proc_self_dirname()
 #elif defined(_WIN32)
 std::string proc_self_dirname()
 {
-	int i = 0;
-	char longpath[MAX_PATH + 1];
-	char shortpath[MAX_PATH + 1];
-	if (!GetModuleFileNameA(0, longpath, MAX_PATH+1))
-		log_error("GetModuleFileName() failed.\n");
-	if (!GetShortPathNameA(longpath, shortpath, MAX_PATH+1))
-		log_error("GetShortPathName() failed.\n");
-	while (shortpath[i] != 0)
-		i++;
-	while (i > 0 && shortpath[i-1] != '/' && shortpath[i-1] != '\\')
-		shortpath[--i] = 0;
-	return shortpath;
+	std::wstring wbinpath(4096, L'\0');
+	if (!GetModuleFileNameW(0, &wbinpath[0], wbinpath.size()))
+	fprintf(stderr, "GetModuleFileNameW() failed.\n");
+	wbinpath.resize(wbinpath.rfind(L'\\') + 1); // remove filename
+	std::string ubinpath;
+	ubinpath.resize(WideCharToMultiByte(CP_UTF8, 0, wbinpath.data(), wbinpath.size(), NULL, 0, NULL, NULL));
+	if (WideCharToMultiByte(CP_UTF8, 0, wbinpath.data(), wbinpath.size(), &ubinpath[0], ubinpath.size(), NULL, NULL) == 0)
+	fprintf(stderr, "WideCharToMultiByte() failed.\n");
+	return ubinpath;
+
 }
 #elif defined(__wasm)
 std::string proc_self_dirname()