Migrate build system to CMake

See #5895 for details.

This commit does not include CI or documentation changes.

flake.nix

@@ -1,47 +1,77 @@
 {
-  description = "A nix flake for the Yosys synthesis suite";
+  description = "A Nix flake for the Yosys synthesis suite.";
 
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    # This requires Nix >= 2.27.0.
+    self.submodules = true;
+
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
     flake-utils.url = "github:numtide/flake-utils";
   };
 
-  outputs = { self, nixpkgs, flake-utils }:
-    flake-utils.lib.eachDefaultSystem (system:
+  outputs =
+    {
+      self,
+      nixpkgs,
+      flake-utils,
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
       let
         pkgs = import nixpkgs {
           inherit system;
+
+          overlays = [
+            (final: prev: {
+              yosys = final.callPackage ./nix/pkgs/yosys.nix {
+                src = self;
+                rev = (self.shortRev or self.dirtyShortRev or "unknown");
+              };
+            })
+          ];
         };
-        # TODO: don't override src when ./abc is empty
-        # which happens when the command used is `nix build` and not `nix build ?submodules=1`
-        abc-verifier = pkgs.abc-verifier;
-        yosys = pkgs.clangStdenv.mkDerivation {
-          name = "yosys";
-          src = ./. ;
-          buildInputs = with pkgs; [ clang bison flex libffi tcl readline python3 zlib git pkg-configUpstream llvmPackages.bintools ];
-          checkInputs = with pkgs; [ gtest ];
-          propagatedBuildInputs = [ abc-verifier ];
-          preConfigure = "make config-clang";
-          checkTarget = "unit-test";
-          installPhase = ''
-            make install PREFIX=$out ABCEXTERNAL=yosys-abc
-            ln -s ${abc-verifier}/bin/abc $out/bin/yosys-abc
-          '';
-					buildPhase = ''
-            make -j$(nproc) ABCEXTERNAL=yosys-abc
-          '';
-          meta = with pkgs.lib; {
-            description = "Yosys Open SYnthesis Suite";
-            homepage = "https://yosyshq.net/yosys/";
-            license = licenses.isc;
-            maintainers = with maintainers; [ ];
+
+        yosys-clang = pkgs.yosys.override { stdenv = pkgs.clangStdenv; };
+
+        win32Pkgs = pkgs.callPackage ./nix/cross/win32.nix { };
+        win64Pkgs = pkgs.callPackage ./nix/cross/win64.nix { };
+
+        mkShell =
+          t:
+          pkgs.mkShell.override { stdenv = t.stdenv; } {
+            inputsFrom = [
+              t
+            ];
+
+            packages = with pkgs; [
+              llvmPackages.clang-tools
+            ];
+
+            shellHook = ''
+              DRIVER_ROOT="${t.stdenv.cc}/bin"
+              export CLANGD_FLAGS="--query-driver $DRIVER_ROOT/$CC,$DRIVER_ROOT/$CXX"
+            '';
           };
+      in
+      {
+        formatter = pkgs.nixfmt-tree;
+
+        devShells = rec {
+          shell = mkShell yosys-clang;
+          shell-gcc = mkShell pkgs.yosys;
+          shell-win32 = mkShell win32Pkgs.yosys;
+          shell-win64 = mkShell win64Pkgs.yosys;
+
+          default = shell;
         };
-      in {
-        packages.default = yosys;
-        defaultPackage = yosys;
-        devShell = pkgs.mkShell {
-          buildInputs = with pkgs; [ clang llvmPackages.bintools gcc bison flex libffi tcl readline python3 zlib git gtest abc-verifier verilog ];
+
+        packages = rec {
+          yosys = yosys-clang;
+          yosys-gcc = pkgs.yosys;
+          yosys-win32 = win32Pkgs.yosys;
+          yosys-win64 = win64Pkgs.yosys;
+
+          default = yosys;
         };
       }
     );