[nix] seperate verilating and linking for better caching

chipsalliance · Jan 21, 2025 · 697766b · 697766b
1 parent 1e24195
commit 697766b
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Showing 4 changed files with 63 additions and 19 deletions.
diff --git a/nix/t1/conversion/link-verilator-with-dpi.nix b/nix/t1/conversion/link-verilator-with-dpi.nix
@@ -0,0 +1,39 @@
+{ lib
+, stdenv
+, zlib
+}:
+
+{ mainProgram
+, verilatorLib
+, dpiLibs
+}:
+
+assert lib.assertMsg (builtins.typeOf dpiLibs == "list") "dpiLibs should be a list of file path";
+
+stdenv.mkDerivation (rec {
+  name = mainProgram;
+  inherit mainProgram;
+
+  dontUnpack = true;
+
+  propagatedBuildInputs = [ zlib ];
+
+  ccArgs = [
+    "${verilatorLib}/lib/libV${verilatorLib.topModule}.a"
+  ]
+  ++ dpiLibs
+  ++ [
+    "${verilatorLib}/lib/libverilated.a"
+    "-lz"
+  ];
+
+  buildCommand = ''
+    mkdir -p $out/bin
+
+    $CXX -o $out/bin/$mainProgram ${lib.escapeShellArgs ccArgs}
+  '';
+
+  passthru = {
+    inherit (verilatorLib) enableTrace;
+  };
+})
diff --git a/nix/t1/conversion/sv-to-verilator-emulator.nix b/nix/t1/conversion/sv-to-verilator-emulator.nix
@@ -6,18 +6,16 @@
 }:
 
 { mainProgram
+, topModule
 , rtl
 , vsrc
 , enableTrace ? false
 , extraVerilatorArgs ? [ ]
-, topModule ? null
-, ...
-}@overrides:
+}:
 
 assert lib.assertMsg (builtins.typeOf vsrc == "list") "vsrc should be a list of file path";
 
-stdenv.mkDerivation (lib.recursiveUpdate
-rec {
+stdenv.mkDerivation (rec {
   name = mainProgram;
   inherit mainProgram;
 
@@ -35,7 +33,6 @@ rec {
   verilatorArgs = [
     "--cc"
     "--main"
-    "--exe"
     "--timescale"
     "1ns/1ps"
     "--timing"
@@ -73,24 +70,22 @@ rec {
     mkdir -p $out/share
     cp -r obj_dir $out/share/verilated_src
 
-    # We can't use -C here because VTestBench.mk is generated with relative path
-    cd obj_dir
-    make -j "$NIX_BUILD_CORES" -f VTestBench.mk VTestBench
+    make -j "$NIX_BUILD_CORES" -f V${topModule}.mk -C obj_dir
 
     runHook postBuild
   '';
 
   passthru = {
+    inherit topModule;
     inherit enableTrace;
   };
 
   installPhase = ''
     runHook preInstall
 
-    mkdir -p $out/{include,lib,bin}
-    cp *.h $out/include
-    cp *.a $out/lib
-    cp VTestBench $out/bin/$mainProgram
+    mkdir -p $out/{include,lib}
+    cp obj_dir/*.h $out/include
+    cp obj_dir/*.a $out/lib
 
     runHook postInstall
   '';
@@ -103,5 +98,4 @@ rec {
   # we'd like verilator to controll optimization flags, so disable it.
   # `-O2` will make gcc build time in verilating extremely long
   hardeningDisable = [ "fortify" ];
-}
-  overrides)
+})
diff --git a/nix/t1/default.nix b/nix/t1/default.nix
@@ -99,6 +99,8 @@ lib.makeScope newScope
     # * verilatorArgs: Final arguments that pass to the verilator.
     sv-to-verilator-emulator = lib.makeOverridable (t1Scope.callPackage ./conversion/sv-to-verilator-emulator.nix { stdenv = moldStdenv; });
 
+    link-verilator-with-dpi = lib.makeOverridable (t1Scope.callPackage ./conversion/link-verilator-with-dpi.nix { stdenv = moldStdenv; });
+
     # sv-to-vcs-simulator :: { mainProgram :: String, rtl :: Derivation, enableTrace :: Bool, vcsLinkLibs :: List<String> } -> Derivation
     #
     # sv-to-vcs-simulator will compile the given rtl, link with path specified in vcsLinksLibs to produce a VCS emulator.

diff --git a/nix/t1/t1.nix b/nix/t1/t1.nix
@@ -117,16 +117,25 @@ forEachTop (topName: generator: self: {
     moduleType = "dpi_${topName}";
   };
 
-  verilator-emu = t1Scope.sv-to-verilator-emulator {
-    mainProgram = "${topName}-verilated-simulator";
+  verilator-emu-lib = t1Scope.sv-to-verilator-emulator {
+    mainProgram = "${topName}-verilated-lib";
     topModule = "TestBench";
     rtl = self.rtl;
     vsrc = lib.filesystem.listFilesRecursive self.clean-vsrc.outPath;
-    extraVerilatorArgs = [ "${self.verilator-dpi-lib}/lib/libdpi_${topName}.a" ];
   };
-  verilator-emu-trace = self.verilator-emu.override {
+  verilator-emu-trace-lib = self.verilator-emu-lib.override {
     enableTrace = true;
+    mainProgram = "${topName}-verilated-trace-lib";
+  };
+
+  verilator-emu = t1Scope.link-verilator-with-dpi {
+    mainProgram = "${topName}-verilated-simulator";
+    verilatorLib = self.verilator-emu-lib;
+    dpiLibs = [ "${self.verilator-dpi-lib}/lib/libdpi_${topName}.a" ];
+  };
+  verilator-emu-trace = self.verilator-emu.override {
     mainProgram = "${topName}-verilated-trace-simulator";
+    verilatorLib = self.verilator-emu-trace-lib;
   };
 
   # ---------------------------------------------------------------------------------