verilator: Generate SystemC

Author: hovind

dependency_support/dependency_support.bzl

@@ -61,6 +61,7 @@ load("//dependency_support/org_theopenroadproject_asap7sc6t_26:org_theopenroadpr
 load("//dependency_support/org_theopenroadproject_asap7sc7p5t_27:org_theopenroadproject_asap7sc7p5t_27.bzl", "org_theopenroadproject_asap7sc7p5t_27")
 load("//dependency_support/org_theopenroadproject_asap7sc7p5t_28:org_theopenroadproject_asap7sc7p5t_28.bzl", "org_theopenroadproject_asap7sc7p5t_28")
 load("//dependency_support/rules_license:rules_license.bzl", "rules_license")
+load("//dependency_support/systemc:systemc.bzl", "systemc")
 load("//dependency_support/tk_tcl:tk_tcl.bzl", "tk_tcl")
 load("//dependency_support/verilator:verilator.bzl", "verilator")
 
@@ -114,6 +115,7 @@ def dependency_support(register_toolchains = True):
     org_theopenroadproject_asap7sc7p5t_27()
     org_theopenroadproject_asap7sc7p5t_28()
     rules_license()
+    systemc()
     tk_tcl()
     verilator()
 

dependency_support/systemc/BUILD.bazel

@@ -0,0 +1,18 @@
+# Copyright 2025 bazel_rules_hdl Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+package(
+    default_applicable_licenses = ["//:package_license"],
+    default_visibility = ["//visibility:private"],
+)

dependency_support/systemc/systemc.BUILD.bazel

@@ -0,0 +1,23 @@
+cc_library(
+    name = "systemc",
+    srcs = glob(
+               ["src/**/*.cpp"],
+               exclude = ["src/sysc/packages/qt/**"],
+           ) +
+           [
+               "src/sysc/packages/qt/qt.c",
+               "src/sysc/packages/qt/md/iX86_64.s",
+           ],
+    hdrs = glob([
+        "src/**/*.h",
+        "src/systemc",
+        "src/tlm",
+    ]),
+    cxxopts = ["-std=c++23"],
+    strip_include_prefix = "src",
+    local_defines = [
+        "SC_BUILD",
+        "SC_INCLUDE_FX",
+    ],
+    visibility = ["//visibility:public"],
+)

dependency_support/systemc/systemc.bzl

@@ -0,0 +1,30 @@
+# Copyright 2020 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Loads the SystemC library."""
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+load("@bazel_tools//tools/build_defs/repo:utils.bzl", "maybe")
+
+def systemc():
+    maybe(
+        http_archive,
+        name = "systemc",
+        urls = [
+            "https://github.com/accellera-official/systemc/archive/refs/tags/3.0.1.tar.gz",
+        ],
+        strip_prefix = "systemc-3.0.1",
+        sha256 = "d07765d0d2ffd6c01767880d0c6aaf53cd9487975f898c593ffffd713258fcbb",
+        build_file = Label("//dependency_support:systemc/systemc.BUILD.bazel"),
+    )

dependency_support/verilator/verilator.BUILD.bazel

@@ -280,6 +280,24 @@ cc_library(
     strip_include_prefix = "include/vltstd",
 )
 
+cc_library(
+    name = "systemc",
+    hdrs = [
+        "include/verilated_fst_sc.cpp",
+        "include/verilated_fst_sc.h",
+        "include/verilated_sc.h",
+        "include/verilated_vcd_sc.cpp",
+        "include/verilated_vcd_sc.h",
+        "include/verilated_sc_trace.h",
+    ],
+    cxxopts = ["-std=c++23"],
+    strip_include_prefix = "include",
+    deps = [
+        "@systemc//:systemc",
+    ],
+    visibility = ["//visibility:public"],
+)
+
 cc_library(
     name = "verilator",
     srcs = [
@@ -302,7 +320,6 @@ cc_library(
         "include/verilated_fst_c.h",
         "include/verilated_funcs.h",
         "include/verilated_intrinsics.h",
-        "include/verilated_sc.h",
         "include/verilated_sym_props.h",
         "include/verilated_threads.h",
         "include/verilated_timing.h",

verilator/BUILD.bazel

@@ -26,6 +26,7 @@ toolchain_type(
 
 verilator_toolchain(
     name = "verilator_toolchain_impl",
+    systemc = "@verilator//:systemc",
     verilator = "@verilator//:verilator_executable",
     deps = [
         "@net_zlib//:zlib",

verilator/defs.bzl

@@ -133,12 +133,16 @@ def _verilator_cc_library(ctx):
     args = ctx.actions.args()
     args.add(verilator_toolchain.verilator)
     args.add("--no-std")
-    args.add("--cc")
     args.add("--Mdir", verilator_output.path)
     args.add("--top-module", ctx.attr.module_top)
     args.add("--prefix", prefix)
     if ctx.attr.trace:
         args.add("--trace")
+    if ctx.attr.systemc:
+        args.add("--sc")
+    else:
+        args.add("--cc")
+
     args.add_all(all_includes, format_each = "-I%s")
     args.add_all(verilog_files, expand_directories = True, map_each = _only_sv)
     args.add_all(verilator_toolchain.extra_vopts)
@@ -186,7 +190,7 @@ def _verilator_cc_library(ctx):
         defines = defines,
         runfiles = runfiles,
         includes = [verilator_output_hpp.path],
-        deps = verilator_toolchain.deps,
+        deps = (verilator_toolchain.deps + [verilator_toolchain.systemc]) if ctx.attr.systemc else verilator_toolchain.deps,
     )
 
 verilator_cc_library = rule(
@@ -205,6 +209,10 @@ verilator_cc_library = rule(
             doc = "The name of the verilog module to verilate.",
             mandatory = True,
         ),
+        "systemc": attr.bool(
+            doc = "Generate SystemC code.",
+            default = False,
+        ),
         "trace": attr.bool(
             doc = "Enable tracing for Verilator",
             default = False,
@@ -246,6 +254,7 @@ def _verilator_toolchain_impl(ctx):
 
     return [platform_common.ToolchainInfo(
         verilator = ctx.executable.verilator,
+        systemc = ctx.attr.systemc,
         deps = ctx.attr.deps,
         extra_vopts = ctx.attr.extra_vopts,
         all_files = all_files,
@@ -266,6 +275,11 @@ verilator_toolchain = rule(
         "extra_vopts": attr.string_list(
             doc = "Extra flags to pass to Verilator compile actions.",
         ),
+        "systemc": attr.label(
+            doc = "SystemC dependency to link into downstream targets.",
+            providers = [CcInfo],
+            mandatory = True,
+        ),
         "verilator": attr.label(
             doc = "The Verilator binary.",
             executable = True,