SVTraceIVerilog.cpp

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//===- SVTraceIVerilog.cpp - Generator Callout Pass -----------------------===//
//
// 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 pass adds the necessary instrumentation to a HWModule to trigger
// tracing in an iverilog simulation.
//
//===----------------------------------------------------------------------===//
 
#include "circt/Dialect/HW/HWInstanceGraph.h"
#include "circt/Dialect/HW/HWOps.h"
#include "circt/Dialect/SV/SVOps.h"
#include "circt/Dialect/SV/SVPasses.h"
#include "mlir/IR/Builders.h"
#include "mlir/Pass/Pass.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Process.h"
 
namespace circt {
namespace sv {
#define GEN_PASS_DEF_SVTRACEIVERILOG
#include "circt/Dialect/SV/SVPasses.h.inc"
} // namespace sv
} // namespace circt
 
using namespace circt;
using namespace sv;
using namespace hw;
 
//===----------------------------------------------------------------------===//
// SVTraceIVerilogPass
//===----------------------------------------------------------------------===//
 
namespace {
 
struct SVTraceIVerilogPass
    : public circt::sv::impl::SVTraceIVerilogBase<SVTraceIVerilogPass> {
  void runOnOperation() override;
};
 
} // end anonymous namespace
 
void SVTraceIVerilogPass::runOnOperation() {
  mlir::ModuleOp mod = getOperation();
 
  if (topOnly) {
    auto &graph = getAnalysis<InstanceGraph>();
    auto topLevelNodes = graph.getInferredTopLevelNodes();
    if (failed(topLevelNodes) || topLevelNodes->size() != 1) {
      mod.emitError("Expected exactly one top level node");
      return signalPassFailure();
    }
    hw::HWModuleOp top =
        dyn_cast_or_null<hw::HWModuleOp>(*topLevelNodes->front()->getModule());
    if (!top) {
      mod.emitError("top module is not a HWModuleOp");
      return signalPassFailure();
    }
    targetModuleName.setValue(top.getName().str());
  }
 
  for (auto hwmod : mod.getOps<hw::HWModuleOp>()) {
    if (!targetModuleName.empty() &&
        hwmod.getName() != targetModuleName.getValue())
      continue;
    OpBuilder builder(hwmod.getBodyBlock(), hwmod.getBodyBlock()->begin());
    std::string traceMacro;
    llvm::raw_string_ostream ss(traceMacro);
    auto modName = hwmod.getName();
    ss << "initial begin\n  $dumpfile (\"" << directoryName.getValue()
       << modName << ".vcd\");\n  $dumpvars (0, " << modName
       << ");\n  #1;\nend\n";
    builder.create<sv::VerbatimOp>(hwmod.getLoc(), ss.str());
  }
}
 
std::unique_ptr<Pass> circt::sv::createSVTraceIVerilogPass() {
  return std::make_unique<SVTraceIVerilogPass>();
}