[nix] add coverage flow for chisel-nix

.github/workflows/main.yml

@@ -56,7 +56,7 @@ jobs:
           ref: ${{ github.event.pull_request.head.sha }}
       - name: "Run VCS"
         run: |
-          nix build '.#gcd.vcs.tests.simple-sim' --impure -L
+          nix build '.#gcd.vcs.tests.simple-sim' --impure -L && cat result/urgReport/asserts.txt
 
   run-verilator:
     name: "Run Verilator"

readme.md

@@ -37,7 +37,7 @@ It's build script is in `nix/gcd` folder, providing the below attributes:
 * [{tb,formal}-]rtl: SystemVerilog generated from the lowered MLIR bytecode
 * tb-dpi-lib: DPI library written in Rust for both Verilator and VCS
 * verilated[-trace]: C++ simulation executable and libaray generated by Verilator with/without `fst` waveform trace
-* vcs[-trace]: C simulation executable compiled by VCS with/without `fsdb` waveform trace
+* vcs[-trace]: C simulation executable compiled by VCS with/without `fsdb` waveform trace and `urgReport` (coverage report) would be generated under `gcd-sim-result/result/`
 * jg-fpv: Formal Property Verification report generated by JasperGold
 
 To get the corresponding output, developers can use:

templates/chisel/nix/gcd/scripts/vcs-wrapper.sh

@@ -6,10 +6,12 @@ if ((${VERBOSE:-0})); then
   set -x
 fi
 
+_LIB=@lib@
 _DATE_BIN=@dateBin@
 _VCS_SIM_BIN=@vcsSimBin@
 _VCS_SIM_DAIDIR=@vcsSimDaidir@
 _VCS_FHS_ENV=@vcsFhsEnv@
+_VCS_COV_DIR=@vcsCovDir@
 
 _NOW=$("$_DATE_BIN" "+%Y-%m-%d-%H-%M-%S")
 _GCD_SIM_RESULT_DIR=${GCD_SIM_RESULT_DIR:-"gcd-sim-result"}
@@ -20,23 +22,29 @@ ln -sfn "all/$_NOW" "$_GCD_SIM_RESULT_DIR/result"
 cp "$_VCS_SIM_BIN" "$_CURRENT/"
 cp -r "$_VCS_SIM_DAIDIR" "$_CURRENT/"
 
-chmod -R +w "$_CURRENT"
+if [ -n "$_VCS_COV_DIR" ]; then
+  cp -vr "$_LIB/$_VCS_COV_DIR" "$_CURRENT/"
+  _CM_ARG="-cm assert -cm_dir $_CURRENT/$_VCS_COV_DIR"
+fi
 
-pushd "$_CURRENT" >/dev/null
+chmod -R +w "$_CURRENT"
 
 _emu_name=$(basename "$_VCS_SIM_BIN")
 _daidir=$(basename "$_VCS_SIM_DAIDIR")
 
-export LD_LIBRARY_PATH="$PWD/$_daidir:$LD_LIBRARY_PATH"
+export LD_LIBRARY_PATH="$_CURRENT/$_daidir:$LD_LIBRARY_PATH"
 
-"$_VCS_FHS_ENV" -c "./$_emu_name $_EXTRA_ARGS" &> >(tee vcs-emu-journal.log)
+"$_VCS_FHS_ENV" -c "$_CURRENT/$_emu_name $_CM_ARG $_EXTRA_ARGS" &> >(tee $_CURRENT/vcs-emu-journal.log)
+
+if [ -n "$_VCS_COV_DIR" ]; then
+  "$_VCS_FHS_ENV" -c "urg -dir "$_CURRENT/$_VCS_COV_DIR" -format text"
+  cp -vr ./urgReport "$_CURRENT/"
+fi
 
 if ((${DATA_ONLY:-0})); then
-  rm -f "./$_emu_name"
+  rm -f "$_CURRENT/$_emu_name"
 fi
 
 set -e _emu_name _daidir
 
-popd >/dev/null
-
 echo "VCS emulator finished, result saved in $_GCD_SIM_RESULT_DIR/result"

templates/chisel/nix/gcd/vcs.nix

@@ -8,10 +8,12 @@
 , dpi-lib
 , vcs-fhs-env
 , runCommand
+, enableCover ? true
 }:
 
 let
   binName = "gcd-vcs-simulator";
+  coverageName = "coverage.vdb";
 in
 stdenv.mkDerivation (finalAttr: {
   name = "vcs";
@@ -41,10 +43,15 @@ stdenv.mkDerivation (finalAttr: {
       ${
         lib.optionalString dpi-lib.enable-trace ''
           -debug_access+pp+dmptf+thread \
-          -kdb=common_elab,hgldd_all''
+          -kdb=common_elab,hgldd_all \
+          -assert enable_diag ''
+      } \
+      ${
+        lib.optionalString enableCover ''
+          -cm line+cond+fsm+tgl+branch+assert \
+          -cm_dir ${coverageName} ''
       } \
       -file filelist.f \
-      -assert enable_diag \
       ${dpi-lib}/lib/${dpi-lib.libOutName} \
       -o ${binName}
 
@@ -79,11 +86,18 @@ stdenv.mkDerivation (finalAttr: {
     cp ${binName} $out/lib
     cp -r ${binName}.daidir $out/lib
 
+    ${
+      lib.optionalString enableCover ''
+      cp -r ${coverageName} $out/lib''
+    } \
+
     substitute ${./scripts/vcs-wrapper.sh} $out/bin/${binName} \
+      --subst-var-by lib "$out/lib" \
       --subst-var-by shell "${bash}/bin/bash" \
       --subst-var-by dateBin "$(command -v date)" \
       --subst-var-by vcsSimBin "$out/lib/${binName}" \
       --subst-var-by vcsSimDaidir "$out/lib/${binName}.daidir" \
+      --subst-var-by vcsCovDir "${lib.optionalString enableCover "${coverageName}"}" \
       --subst-var-by vcsFhsEnv "${vcs-fhs-env}/bin/vcs-fhs-env"
     chmod +x $out/bin/${binName}