From 6039446e602862e2b5a78e7cb3a678ee88f55576 Mon Sep 17 00:00:00 2001
From: Miodrag Milanovic <mmicko@gmail.com>
Date: Fri, 22 May 2026 19:54:19 +0200
Subject: [PATCH] Visual Studio build

---
 .github/workflows/extra-builds.yml | 72 +++++++++++++++---------------
 CMakeLists.txt                     | 12 ++++-
 cmake/FindDlfcn.cmake              |  5 ++-
 3 files changed, 51 insertions(+), 38 deletions(-)

diff --git a/.github/workflows/extra-builds.yml b/.github/workflows/extra-builds.yml
index 47d65cb9a..cdf0c7fd5 100644
--- a/.github/workflows/extra-builds.yml
+++ b/.github/workflows/extra-builds.yml
@@ -31,41 +31,41 @@ jobs:
             echo "should_skip=${{ steps.skip_check.outputs.should_skip }}" >> $GITHUB_OUTPUT
           fi
 
-#  vs-prep:
-#    name: Prepare Visual Studio build
-#    runs-on: ubuntu-latest
-#    needs: [pre_job]
-#    if: (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch') && needs.pre_job.outputs.should_skip != 'true'
-#    steps:
-#      - uses: actions/checkout@v5
-#        with:
-#          submodules: true
-#          persist-credentials: false
-#      - run: sudo apt-get install libfl-dev
-#      - name: Build
-#        run: make vcxsrc YOSYS_COMPILER="Visual Studio" VCX_DIR_NAME=yosys-win32-vcxsrc-latest
-#      - uses: actions/upload-artifact@v7
-#        with:
-#          name: vcxsrc
-#          path: yosys-win32-vcxsrc-latest.zip
-#
-#  vs-build:
-#    name: Visual Studio build
-#    runs-on: windows-latest
-#    needs: [vs-prep, pre_job]
-#    if: (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch') && needs.pre_job.outputs.should_skip != 'true'
-#    steps:
-#      - uses: actions/download-artifact@v8
-#        with:
-#          name: vcxsrc
-#          path: .
-#      - name: unzip
-#        run: unzip yosys-win32-vcxsrc-latest.zip
-#      - name: setup-msbuild
-#        uses: microsoft/setup-msbuild@v2
-#      - name: MSBuild
-#        working-directory: yosys-win32-vcxsrc-latest
-#        run: msbuild YosysVS.sln /p:PlatformToolset=v142 /p:Configuration=Release /p:WindowsTargetPlatformVersion=10.0.26100.0
+  vs-build:
+    name: Visual Studio build
+    runs-on: windows-latest
+    needs: [pre_job]
+    if: (github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch') && needs.pre_job.outputs.should_skip != 'true'
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          submodules: true
+          persist-credentials: false
+
+      - name: Setup MSVC
+        uses: ilammy/msvc-dev-cmd@v1
+
+      - name: Install flex/bison
+        shell: pwsh
+        run: |
+          choco install winflexbison3 --no-progress
+
+          # Make tools visible to CMake
+          echo "C:\Program Files (x86)\GnuWin32\bin" | Out-File -Append -FilePath $env:GITHUB_PATH
+          echo "C:\ProgramData\chocolatey\lib\winflexbison3\tools" | Out-File -Append -FilePath $env:GITHUB_PATH
+
+      - name: Configure CMake
+        run: >
+          cmake -S . -B build
+          -A x64
+          -DCMAKE_BUILD_TYPE=Release
+          -DYOSYS_WITHOUT_ABC=ON
+
+      - name: Build
+        run: >
+          cmake --build build
+          --config Release
+          --parallel
 
   wasi-build:
     name: WASI build
@@ -121,7 +121,7 @@ jobs:
   extra-builds-result:
     runs-on: ubuntu-latest
     needs:
-#      - vs-build
+      - vs-build
       - wasi-build
       - nix-build
     if: always()
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d91440266..a9570e836 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -99,7 +99,14 @@ elseif (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
 	set(CMAKE_CXX_FLAGS_RELEASE "/O2")
 	set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "/O2 /DEBUG")
 	set(CMAKE_CXX_FLAGS_MINSIZEREL "/Os")
-	add_definitions(_CRT_SECURE_NO_WARNINGS)
+	add_compile_definitions(
+		_CRT_NONSTDC_NO_DEPRECATE
+		_CRT_SECURE_NO_WARNINGS
+		NOMINMAX
+		UNICODE
+		_UNICODE
+	)
+	add_compile_options(/Zc:__cplusplus)
 else()
 	# We have to do this because CMake adds `-DNDEBUG` in release builds by default, and there's
 	# no particularly good way to prevent this without also erasing optimization flags.
@@ -289,6 +296,9 @@ condition(YOSYS_ENABLE_EDITLINE editline_FOUND AND NOT YOSYS_WITHOUT_EDITLINE AN
 condition(YOSYS_ENABLE_TCL tcl_FOUND AND libtommath_FOUND AND NOT YOSYS_WITHOUT_TCL)
 condition(YOSYS_ENABLE_PYTHON Python3Embed_FOUND AND PyosysEnv_FOUND AND YOSYS_WITH_PYTHON)
 condition(YOSYS_ENABLE_VERIFIC YOSYS_VERIFIC_DIR AND zlib_FOUND)
+if (MSVC)
+    set(YOSYS_ENABLE_SPAWN ON)
+endif()
 
 # Describe dependencies and features
 # CMake 4.0 would let us use proper conditions, but that's too new for now.
diff --git a/cmake/FindDlfcn.cmake b/cmake/FindDlfcn.cmake
index 201745a3f..8ef21616a 100644
--- a/cmake/FindDlfcn.cmake
+++ b/cmake/FindDlfcn.cmake
@@ -2,7 +2,10 @@ include(CMakePushCheckState)
 include(CheckCXXSymbolExists)
 include(FindPackageHandleStandardArgs)
 
-if (WIN32 OR MSYS)
+if (MSVC)
+	set(Dlfcn_FOUND FALSE)
+	unset(Dlfcn_LIBRARIES CACHE)
+elseif (WIN32 OR MSYS)
 	# Windows; dlopen is available via a polyfill `libs/dlfcn-win32`.
 	set(Dlfcn_LIBRARIES dlfcn)
 else()