[ImportVerilog] Add Slang frontend dependency (#6620)

This is the first PR in a longer chain that adds basic SV support to
CIRCT.

Add the Slang Verilog frontend as a CIRCT dependency. This will be the
foundation for CIRCT's Verilog parsing, elaboration, type checking, and
lowering to the core dialects. By default, Slang is built as a static
library from scratch, which is then linked into the new `ImportVerilog`
conversion. Alternatively, CIRCT can also be linked against a local
Slang installation provided by the system.

Add the `ImportVerilog` conversion library. This library statically
links in the Slang dependency and wraps it in an exception-safe,
LLVM-style API. Currently this only consists of the `getSlangVersion`
function and the necessary linking flags to get it to link statically
against Slang.

Add the `circt-verilog` tool, which will provide a fully-flegded
interface to the new `ImportVerilog` library. Later on we'll also add an
MLIR translation library for single-file SV import. But in general, SV
builds take a lot of command line options (macros, search paths, etc.)
and multiple input files, which is why we have a dedicated tool. All the
tool does at the moment is print the linked Slang version. More to come.

Note that this intentionally links against **version 3** of Slang. Newer
versions are available -- 4 and 5 as of this commit -- but they rely on
fairly new C++ compiler features that didn't work out of the box in our
CI images. We'll eventually want to upgrade, but for now Slang 3 is
sufficient to get the ball rolling.

See https://github.com/MikePopoloski/slang for details on Slang.

Co-authored-by: ShiZuoye <albertethon@163.com>
Co-authored-by: hunterzju <hunter_ht@zju.edu.cn>
Co-authored-by: 孙海龙 <hailong.sun@terapines.com>

.github/workflows/buildAndTest.yml

@@ -220,7 +220,8 @@ jobs:
             -DCMAKE_CXX_COMPILER=${{ matrix.compiler.cxx }} \
             -DLLVM_EXTERNAL_LIT=`pwd`/../llvm/build/bin/llvm-lit \
             -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
-            -DLLVM_LIT_ARGS="-v"
+            -DLLVM_LIT_ARGS="-v" \
+            -DCIRCT_SLANG_FRONTEND_ENABLED=ON
           ninja check-circt check-circt-unit -j$(nproc)
           ninja circt-doc
 

.github/workflows/nightlyIntegrationTests.yml

@@ -96,7 +96,8 @@ jobs:
             -DMLIR_ENABLE_BINDINGS_PYTHON=ON \
             -DCIRCT_BINDINGS_PYTHON_ENABLED=ON \
             -DESI_RUNTIME=ON \
-            -DLLVM_LIT_ARGS="-v --show-unsupported ${{ matrix.lit-flags }}"
+            -DLLVM_LIT_ARGS="-v --show-unsupported ${{ matrix.lit-flags }}" \
+            -DCIRCT_SLANG_FRONTEND_ENABLED=ON
       - name: Test CIRCT
         run: |
           ninja -C build check-circt -j$(nproc)

.github/workflows/shortIntegrationTests.yml

@@ -89,7 +89,8 @@ jobs:
             -DMLIR_ENABLE_BINDINGS_PYTHON=ON \
             -DCIRCT_BINDINGS_PYTHON_ENABLED=ON \
             -DESI_RUNTIME=ON \
-            -DLLVM_LIT_ARGS="-v --show-unsupported"
+            -DLLVM_LIT_ARGS="-v --show-unsupported" \
+            -DCIRCT_SLANG_FRONTEND_ENABLED=ON
       - name: Test CIRCT
         run: |
           ninja -C build check-circt -j$(nproc)

.github/workflows/unifiedBuildTestAndInstall.yml

@@ -177,7 +177,7 @@ jobs:
           ${{ steps.setup-windows.outputs.setup }}
           mkdir build
           cd build
-          cmake -G Ninja -S "$(pwd)/../llvm/llvm" $EXTRA_CMAKE_ARGS -DCMAKE_BUILD_TYPE=${{ inputs.cmake_build_type }} -DBUILD_SHARED_LIBS=${{ inputs.build_shared_libs }} -DLLVM_BUILD_TOOLS=ON -DLLVM_BUILD_EXAMPLES=OFF -DLLVM_ENABLE_ASSERTIONS=${{ inputs.llvm_enable_assertions }} -DLLVM_ENABLE_PROJECTS=mlir -DLLVM_EXTERNAL_PROJECTS=circt -DLLVM_EXTERNAL_CIRCT_SOURCE_DIR=".." -DLLVM_STATIC_LINK_CXX_STDLIB=ON -DLLVM_ENABLE_TERMINFO=OFF -DLLVM_PARALLEL_LINK_JOBS=1 -DLLVM_TARGETS_TO_BUILD="host" -DLLVM_FORCE_ENABLE_STATS=${{ inputs.llvm_force_enable_stats }} -DLLVM_ENABLE_ZSTD=OFF -DVERILATOR_DISABLE=ON -DLLVM_PARALLEL_LINK_JOBS=1 -DCIRCT_RELEASE_TAG_ENABLED=ON -DCIRCT_RELEASE_TAG=firtool -DCMAKE_EXPORT_COMPILE_COMMANDS=OFF -DCMAKE_C_COMPILER=${{ inputs.cmake_c_compiler }} -DCMAKE_CXX_COMPILER=${{ inputs.cmake_cxx_compiler }} ${{ steps.configure-sccache.outputs.enable_sccache }} -DCMAKE_INSTALL_PREFIX="$(pwd)/../install" -DLLVM_INSTALL_UTILS=ON
+          cmake -G Ninja -S "$(pwd)/../llvm/llvm" $EXTRA_CMAKE_ARGS -DCMAKE_BUILD_TYPE=${{ inputs.cmake_build_type }} -DBUILD_SHARED_LIBS=${{ inputs.build_shared_libs }} -DLLVM_BUILD_TOOLS=ON -DLLVM_BUILD_EXAMPLES=OFF -DLLVM_ENABLE_ASSERTIONS=${{ inputs.llvm_enable_assertions }} -DLLVM_ENABLE_PROJECTS=mlir -DLLVM_EXTERNAL_PROJECTS=circt -DLLVM_EXTERNAL_CIRCT_SOURCE_DIR=".." -DLLVM_STATIC_LINK_CXX_STDLIB=ON -DLLVM_ENABLE_TERMINFO=OFF -DLLVM_PARALLEL_LINK_JOBS=1 -DLLVM_TARGETS_TO_BUILD="host" -DLLVM_FORCE_ENABLE_STATS=${{ inputs.llvm_force_enable_stats }} -DLLVM_ENABLE_ZSTD=OFF -DVERILATOR_DISABLE=ON -DLLVM_PARALLEL_LINK_JOBS=1 -DCIRCT_RELEASE_TAG_ENABLED=ON -DCIRCT_RELEASE_TAG=firtool -DCMAKE_EXPORT_COMPILE_COMMANDS=OFF -DCMAKE_C_COMPILER=${{ inputs.cmake_c_compiler }} -DCMAKE_CXX_COMPILER=${{ inputs.cmake_cxx_compiler }} ${{ steps.configure-sccache.outputs.enable_sccache }} -DCMAKE_INSTALL_PREFIX="$(pwd)/../install" -DLLVM_INSTALL_UTILS=ON -DCIRCT_SLANG_FRONTEND_ENABLED=ON
 # Optionally test
       - name: Test CIRCT
         if: inputs.runTests

CMakeLists.txt

@@ -25,6 +25,10 @@ if(POLICY CMP0116)
   cmake_policy(SET CMP0116 OLD)
 endif()
 
+if(POLICY CMP0135)
+  cmake_policy(SET CMP0135 NEW)
+endif()
+
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED YES)
 
@@ -523,6 +527,62 @@ if(CIRCT_BINDINGS_TCL_ENABLED)
   message(STATUS "Found TCL executable: ${TCL_TCLSH}")
 endif()
 
+#-------------------------------------------------------------------------------
+# slang Verilog Frontend
+#-------------------------------------------------------------------------------
+
+option(CIRCT_SLANG_FRONTEND_ENABLED "Enables the slang Verilog frontend." OFF)
+option(CIRCT_SLANG_BUILD_FROM_SOURCE
+  "Build slang from source instead of finding an installed package" ON)
+
+llvm_canonicalize_cmake_booleans(CIRCT_SLANG_FRONTEND_ENABLED)
+llvm_canonicalize_cmake_booleans(CIRCT_SLANG_BUILD_FROM_SOURCE)
+
+if(CIRCT_SLANG_FRONTEND_ENABLED)
+  message(STATUS "slang Verilog frontend is enabled")
+  if(CIRCT_SLANG_BUILD_FROM_SOURCE)
+    # Build slang as part of CIRCT (see https://sv-lang.com/building.html)
+    message(STATUS "Building slang from source")
+    include(FetchContent)
+    FetchContent_Declare(
+      slang
+      URL https://github.com/MikePopoloski/slang/archive/refs/tags/v3.0.tar.gz
+      URL_HASH SHA256=02d184133525f6330a32bef492761b8ff52d0a33caed08eb51733f63cddb08e3
+    )
+    set(FETCHCONTENT_TRY_FIND_PACKAGE_MODE "NEVER")
+
+    # Force Slang to be built as a static library to avoid messing around with
+    # RPATHs and installing a slang dylib alongside CIRCT. The static library
+    # will embed Slang into ImportVerilog.
+    set(ORIGINAL_CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
+    set(ORIGINAL_BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS})
+
+    set(CMAKE_CXX_FLAGS "")
+    set(BUILD_SHARED_LIBS OFF)
+    FetchContent_MakeAvailable(slang)
+
+    set(CMAKE_CXX_FLAGS ${ORIGINAL_CMAKE_CXX_FLAGS})
+    set(BUILD_SHARED_LIBS ${ORIGINAL_BUILD_SHARED_LIBS})
+
+    if(BUILD_SHARED_LIBS)
+      set_target_properties(slang_slang PROPERTIES POSITION_INDEPENDENT_CODE ON)
+      set_target_properties(fmt PROPERTIES POSITION_INDEPENDENT_CODE ON)
+      set_target_properties(unordered_dense PROPERTIES POSITION_INDEPENDENT_CODE ON)
+    endif()
+
+    # The following feels *very* hacky, but CMake complains about the
+    # CIRCTImportVerilog target linking against slang_slang (even with PRIVATE
+    # linking) without the latter being in an export set. I think we'd want to
+    # statically link slang into the CIRCTImportVerilog library, but seems to be
+    # harder than it ought to be.
+    set_property(
+      GLOBAL APPEND PROPERTY CIRCT_EXPORTS slang_slang unordered_dense fmt)
+    install(TARGETS slang_slang unordered_dense fmt EXPORT CIRCTTargets)
+  else()
+    find_package(slang 3.0 REQUIRED)
+  endif()
+endif()
+
 #-------------------------------------------------------------------------------
 # Directory setup
 #-------------------------------------------------------------------------------

include/circt/Conversion/ImportVerilog.h

@@ -0,0 +1,26 @@
+//===- ImportVerilog.h - Slang Verilog frontend integration ---------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Defines the interface to the Verilog frontend.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CIRCT_CONVERSION_IMPORTVERILOG_H
+#define CIRCT_CONVERSION_IMPORTVERILOG_H
+
+#include <string>
+
+namespace circt {
+
+/// Return a human-readable string describing the slang frontend version linked
+/// into CIRCT.
+std::string getSlangVersion();
+
+} // namespace circt
+
+#endif // CIRCT_CONVERSION_IMPORTVERILOG_H

lib/Conversion/CMakeLists.txt

@@ -28,3 +28,7 @@ add_subdirectory(SimToSV)
 add_subdirectory(CFToHandshake)
 add_subdirectory(VerifToSV)
 add_subdirectory(CalyxNative)
+
+if(CIRCT_SLANG_FRONTEND_ENABLED)
+  add_subdirectory(ImportVerilog)
+endif()

lib/Conversion/ImportVerilog/CMakeLists.txt

@@ -0,0 +1,38 @@
+# slang uses exceptions
+set(LLVM_REQUIRES_EH ON)
+set(LLVM_REQUIRES_RTTI ON)
+
+# For ABI compatibility, define the DEBUG macro in debug builds. Slang sets this
+# internally. If we don't set this here as well, header-defined things like the
+# destructor of `Driver`, which is generated in ImportVerilog's compilation
+# unit, will destroy a different set of fields than what was potentially built
+# or modified by code compiled in the Slang compilation unit.
+add_compile_definitions($<$<CONFIG:Debug>:DEBUG>)
+
+# Disable some compiler warnings caused by slang headers such that the
+# `ImportVerilog` build doesn't spew out a ton of warnings that are not related
+# to CIRCT.
+if (MSVC)
+  # No idea what to put here
+else ()
+  # slang uses exceptions; we intercept these in ImportVerilog
+  add_compile_options(-fexceptions)
+  add_compile_options(-frtti)
+  # slang has some classes with virtual funcs but non-virtual destructor.
+  add_compile_options(-Wno-non-virtual-dtor)
+  # some other warnings we've seen
+  add_compile_options(-Wno-c++98-compat-extra-semi)
+  add_compile_options(-Wno-ctad-maybe-unsupported)
+  add_compile_options(-Wno-cast-qual)
+  # visitor switch statements cover all cases but have default
+  add_compile_options(-Wno-covered-switch-default)
+endif ()
+
+add_circt_translation_library(CIRCTImportVerilog
+  ImportVerilog.cpp
+
+  LINK_LIBS PUBLIC
+  MLIRTranslateLib
+  PRIVATE
+  slang_slang
+)

lib/Conversion/ImportVerilog/ImportVerilog.cpp

@@ -0,0 +1,27 @@
+//===- ImportVerilog.cpp - Slang Verilog frontend integration -------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements bridging from the slang Verilog frontend to CIRCT dialects.
+//
+//===----------------------------------------------------------------------===//
+
+#include "circt/Conversion/ImportVerilog.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include "slang/util/Version.h"
+
+std::string circt::getSlangVersion() {
+  std::string buffer;
+  llvm::raw_string_ostream os(buffer);
+  os << "slang version ";
+  os << slang::VersionInfo::getMajor() << ".";
+  os << slang::VersionInfo::getMinor() << ".";
+  os << slang::VersionInfo::getPatch() << "+";
+  os << slang::VersionInfo::getHash();
+  return buffer;
+}

test/CMakeLists.txt

@@ -43,6 +43,10 @@ if(CIRCT_LLHD_SIM_ENABLED)
   list(APPEND CIRCT_TEST_DEPENDS circt-llhd-signals-runtime-wrappers)
 endif()
 
+if(CIRCT_SLANG_FRONTEND_ENABLED)
+  list(APPEND CIRCT_TEST_DEPENDS circt-verilog)
+endif()
+
 add_lit_testsuite(check-circt "Running the CIRCT regression tests"
   ${CMAKE_CURRENT_BINARY_DIR}
   DEPENDS ${CIRCT_TEST_DEPENDS}

test/circt-verilog/commandline.sv

@@ -0,0 +1,6 @@
+// RUN: circt-verilog -h | FileCheck %s --check-prefix=CHECK-HELP
+// RUN: circt-verilog --version | FileCheck %s --check-prefix=CHECK-VERSION
+// REQUIRES: slang
+
+// CHECK-HELP: OVERVIEW: Verilog and SystemVerilog frontend
+// CHECK-VERSION: slang version 3.

test/lit.cfg.py

@@ -84,4 +84,9 @@ if config.llhd_sim_enabled:
   config.available_features.add('llhd-sim')
   tools.append('llhd-sim')
 
+# Add circt-verilog if the Slang frontend is enabled.
+if config.slang_frontend_enabled:
+  config.available_features.add('slang')
+  tools.append('circt-verilog')
+
 llvm_config.add_tool_substitutions(tools, tool_dirs)

test/lit.site.cfg.py.in

@@ -40,6 +40,7 @@ config.esi_capnp = "@ESI_CAPNP@"
 config.zlib = "@HAVE_ZLIB@"
 config.scheduling_or_tools = "@SCHEDULING_OR_TOOLS@"
 config.llhd_sim_enabled = @CIRCT_LLHD_SIM_ENABLED@
+config.slang_frontend_enabled = @CIRCT_SLANG_FRONTEND_ENABLED@
 
 # Support substitution of the tools_dir with user parameters. This is
 # used when we can't determine the tool dir at configuration time.

tools/CMakeLists.txt

@@ -16,3 +16,7 @@ add_subdirectory(om-linker)
 add_subdirectory(py-split-input-file)
 add_subdirectory(hlstool)
 add_subdirectory(ibistool)
+
+if(CIRCT_SLANG_FRONTEND_ENABLED)
+  add_subdirectory(circt-verilog)
+endif()

tools/circt-verilog/CMakeLists.txt

@@ -0,0 +1,11 @@
+add_circt_tool(circt-verilog
+  circt-verilog.cpp
+)
+
+llvm_update_compile_flags(circt-verilog)
+
+target_link_libraries(circt-verilog PRIVATE
+  CIRCTImportVerilog
+  CIRCTSupport
+  MLIRIR
+)

tools/circt-verilog/circt-verilog.cpp

@@ -0,0 +1,61 @@
+//===- circt-verilog.cpp - Getting Verilog into CIRCT ---------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a utility to parse Verilog and SystemVerilog input
+// files. This builds on CIRCT's ImportVerilog library, which ultimately relies
+// on slang to do the heavy lifting.
+//
+//===----------------------------------------------------------------------===//
+
+#include "circt/Conversion/ImportVerilog.h"
+#include "circt/Support/Version.h"
+#include "mlir/IR/BuiltinOps.h"
+#include "mlir/Pass/PassManager.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/InitLLVM.h"
+
+using namespace llvm;
+using namespace mlir;
+using namespace circt;
+
+//===----------------------------------------------------------------------===//
+// Implementation
+//===----------------------------------------------------------------------===//
+
+static LogicalResult execute(MLIRContext *context) {
+  // This is where we would call out to ImportVerilog to parse the input.
+  return success();
+}
+
+int main(int argc, char **argv) {
+  InitLLVM y(argc, argv);
+
+  // Set the bug report message to indicate users should file issues on
+  // llvm/circt and not llvm/llvm-project.
+  setBugReportMsg(circtBugReportMsg);
+
+  // Print the CIRCT and Slang versions when requested.
+  cl::AddExtraVersionPrinter([](raw_ostream &os) {
+    os << getCirctVersion() << '\n';
+    os << getSlangVersion() << '\n';
+  });
+
+  // Register any pass manager command line options.
+  registerMLIRContextCLOptions();
+  registerPassManagerCLOptions();
+  registerDefaultTimingManagerCLOptions();
+  registerAsmPrinterCLOptions();
+
+  // Parse pass names in main to ensure static initialization completed.
+  cl::ParseCommandLineOptions(argc, argv,
+                              "Verilog and SystemVerilog frontend\n");
+
+  // Perform the actual work and use "exit" to avoid slow context teardown.
+  MLIRContext context;
+  exit(failed(execute(&context)));
+}