diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
new file mode 100644
--- /dev/null
+++ b/flang/lib/Lower/Bridge.cpp
@@ -0,0 +1,131 @@
+#include "flang/Lower/Bridge.h"
+#include "flang/Evaluate/common.h"
+#include "flang/Lower/PFTBuilder.h"
+#include "flang/Semantics/symbol.h"
+#include "llvm/Support/CommandLine.h"
+
+static llvm::cl::opt<bool> dumpBeforeFir(
+    "fdebug-dump-pre-fir", llvm::cl::init(false),
+    llvm::cl::desc("dump the Pre-FIR tree prior to FIR generation"));
+
+//===----------------------------------------------------------------------===//
+// FirConverter
+//===----------------------------------------------------------------------===//
+
+namespace {
+/// Walk over the pre-FIR tree (PFT) and lower it to the FIR dialect of MLIR.
+///
+/// After building the PFT, the FirConverter processes that representation
+/// and lowers it to the FIR executable representation.
+class FirConverter {
+public:
+  explicit FirConverter(Fortran::lower::LoweringBridge &bridge,
+                        fir::NameUniquer &uniquer)
+      : bridge{bridge}, uniquer{uniquer}, foldingContext{
+                                              bridge.createFoldingContext()} {}
+  virtual ~FirConverter() = default;
+
+  /// Convert the PFT to FIR
+  void run(Fortran::lower::pft::Program &pft) {
+    // do translation
+    for (auto &u : pft.getUnits()) {
+      std::visit(Fortran::common::visitors{
+                     [&](Fortran::lower::pft::FunctionLikeUnit &f) {
+                       mlir::emitError(toLocation(), "FUNCTION not handled");
+                       llvm::report_fatal_error("not yet implemented");
+                     },
+                     [&](Fortran::lower::pft::ModuleLikeUnit &m) {
+                       mlir::emitError(toLocation(), "MODULE not handled");
+                       llvm::report_fatal_error("not yet implemented");
+                     },
+                     [&](Fortran::lower::pft::BlockDataUnit &) {
+                       mlir::emitError(toLocation(), "BLOCK DATA not handled");
+                       llvm::report_fatal_error("not yet implemented");
+                     },
+                 },
+                 u);
+    }
+  }
+
+private:
+  /// Generate a `Location` from the `CharBlock`.
+  mlir::Location genLocation(const Fortran::parser::CharBlock &block) {
+    if (const auto *cooked = bridge.getCookedSource()) {
+      auto loc = cooked->GetSourcePositionRange(block);
+      if (loc.has_value()) {
+        // loc is a pair (begin, end); use the beginning position
+        auto &filePos = loc->first;
+        return mlir::FileLineColLoc::get(filePos.file.path(), filePos.line,
+                                         filePos.column, &getMLIRContext());
+      }
+    }
+    return genLocation();
+  }
+
+  mlir::MLIRContext &getMLIRContext() { return bridge.getMLIRContext(); }
+
+  /// Generate a dummy location.
+  mlir::Location genLocation() {
+    // Note: builder may not be instantiated yet
+    return mlir::UnknownLoc::get(&getMLIRContext());
+  }
+
+  /// Convert a parser CharBlock to a Location
+  mlir::Location toLocation(const Fortran::parser::CharBlock &cb) {
+    return genLocation(cb);
+  }
+
+  mlir::Location toLocation() { return toLocation(currentPosition); }
+
+  [[maybe_unused]] Fortran::lower::LoweringBridge &bridge;
+  [[maybe_unused]] fir::NameUniquer &uniquer;
+  Fortran::evaluate::FoldingContext foldingContext;
+  Fortran::parser::CharBlock currentPosition;
+};
+} // namespace
+
+Fortran::evaluate::FoldingContext
+Fortran::lower::LoweringBridge::createFoldingContext() const {
+  return {getDefaultKinds(), getIntrinsicTable()};
+}
+
+void Fortran::lower::LoweringBridge::lower(
+    const Fortran::parser::Program &prg, fir::NameUniquer &uniquer,
+    const Fortran::semantics::SemanticsContext &semanticsContext) {
+  auto pft = Fortran::lower::createPFT(prg, semanticsContext);
+  if (dumpBeforeFir)
+    Fortran::lower::dumpPFT(llvm::errs(), *pft);
+  FirConverter converter{*this, uniquer};
+  converter.run(*pft);
+}
+
+Fortran::lower::LoweringBridge::LoweringBridge(
+    const Fortran::common::IntrinsicTypeDefaultKinds &defaultKinds,
+    const Fortran::evaluate::IntrinsicProcTable &intrinsics,
+    const Fortran::parser::CookedSource &cooked)
+    : defaultKinds{defaultKinds}, intrinsics{intrinsics}, cooked{&cooked},
+      context{std::make_unique<mlir::MLIRContext>()}, kindMap{context.get()} {
+  context.get()->getDiagEngine().registerHandler([](mlir::Diagnostic &diag) {
+    auto &os = llvm::errs();
+    switch (diag.getSeverity()) {
+    case mlir::DiagnosticSeverity::Error:
+      os << "error: ";
+      break;
+    case mlir::DiagnosticSeverity::Remark:
+      os << "info: ";
+      break;
+    case mlir::DiagnosticSeverity::Warning:
+      os << "warning: ";
+      break;
+    default:
+      break;
+    }
+    if (!diag.getLocation().isa<mlir::UnknownLoc>())
+      os << diag.getLocation() << ": ";
+    os << diag << '\n';
+    os.flush();
+    return mlir::success();
+  });
+  module = std::make_unique<mlir::ModuleOp>(
+      mlir::ModuleOp::create(mlir::UnknownLoc::get(context.get())));
+}
diff --git a/flang/lib/Lower/CMakeLists.txt b/flang/lib/Lower/CMakeLists.txt
--- a/flang/lib/Lower/CMakeLists.txt
+++ b/flang/lib/Lower/CMakeLists.txt
@@ -2,6 +2,7 @@
 get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
 
 add_flang_library(FortranLower
+  Bridge.cpp
   CharacterExpr.cpp
   CharacterRuntime.cpp
   Coarray.cpp
diff --git a/flang/test/Lower/block-data.f90 b/flang/test/Lower/block-data.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Lower/block-data.f90
@@ -0,0 +1,6 @@
+! RUN: not --crash bbc -o - %s 2>&1 | FileCheck %s
+
+block data
+! CHECK: error: BLOCK DATA not handled
+! CHECK: LLVM ERROR: not yet implemented
+end block data
diff --git a/flang/tools/CMakeLists.txt b/flang/tools/CMakeLists.txt
--- a/flang/tools/CMakeLists.txt
+++ b/flang/tools/CMakeLists.txt
@@ -9,5 +9,6 @@
 add_subdirectory(f18)
 if(LINK_WITH_FIR)
   add_subdirectory(tco)
+  add_subdirectory(bbc)
 endif()
 add_subdirectory(f18-parse-demo)
diff --git a/flang/tools/bbc/CMakeLists.txt b/flang/tools/bbc/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/flang/tools/bbc/CMakeLists.txt
@@ -0,0 +1,17 @@
+get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
+
+set(LIBS
+  FIROptimizer
+  ${dialect_libs}
+  MLIRLLVMIR
+  MLIRAffineToStandard
+  FortranCommon
+  FortranParser
+  FortranEvaluate
+  FortranSemantics
+  FortranLower
+  )
+
+add_flang_tool(bbc bbc.cpp)
+llvm_update_compile_flags(bbc)
+target_link_libraries(bbc PRIVATE ${LIBS})
diff --git a/flang/tools/bbc/bbc.cpp b/flang/tools/bbc/bbc.cpp
new file mode 100644
--- /dev/null
+++ b/flang/tools/bbc/bbc.cpp
@@ -0,0 +1,203 @@
+#include "flang/Lower/Bridge.h"
+#include "flang/Lower/PFTBuilder.h"
+#include "flang/Optimizer/Dialect/FIRDialect.h"
+#include "flang/Optimizer/Support/InternalNames.h"
+#include "flang/Parser/parsing.h"
+#include "flang/Semantics/semantics.h"
+#include "mlir/IR/AsmState.h"
+#include "mlir/Pass/Pass.h"
+#include "mlir/Pass/PassManager.h"
+#include "mlir/Transforms/Passes.h"
+#include "llvm/Support/InitLLVM.h"
+#include <string>
+
+//===----------------------------------------------------------------------===//
+// Some basic command-line options
+//===----------------------------------------------------------------------===//
+
+static llvm::cl::opt<std::string> inputFilename(llvm::cl::Positional,
+                                                llvm::cl::Required,
+                                                llvm::cl::desc("<input file>"));
+
+static llvm::cl::opt<std::string>
+    outputFilename("o", llvm::cl::desc("Specify the output filename"),
+                   llvm::cl::value_desc("filename"));
+
+static llvm::cl::list<std::string>
+    includeDirs("I", llvm::cl::desc("include search paths"));
+
+static llvm::cl::opt<std::string>
+    intrinsicModuleDir("intrinsic-module-directory",
+                       llvm::cl::desc("intrinsic module directory"));
+
+static llvm::cl::opt<std::string>
+    moduleDir("module", llvm::cl::desc("module output directory (default .)"),
+              llvm::cl::init("."));
+
+static llvm::cl::opt<std::string>
+    moduleSuffix("module-suffix", llvm::cl::desc("module file suffix override"),
+                 llvm::cl::init(".mod"));
+
+static llvm::cl::opt<bool> warnStdViolation("Mstandard",
+                                            llvm::cl::desc("emit warnings"),
+                                            llvm::cl::init(false));
+
+static llvm::cl::opt<bool> warnIsError("Werror",
+                                       llvm::cl::desc("warnings are errors"),
+                                       llvm::cl::init(false));
+
+static llvm::cl::opt<bool> fixedForm("Mfixed",
+                                     llvm::cl::desc("used fixed form"),
+                                     llvm::cl::init(false));
+
+static llvm::cl::opt<bool> freeForm("Mfree", llvm::cl::desc("used free form"),
+                                    llvm::cl::init(false));
+
+static llvm::cl::opt<bool> dumpSymbols("dump-symbols",
+                                       llvm::cl::desc("dump the symbol table"),
+                                       llvm::cl::init(false));
+
+static llvm::cl::opt<bool> pftDumpTest(
+    "pft-test",
+    llvm::cl::desc("parse the input, create a PFT, dump it, and exit"),
+    llvm::cl::init(false));
+
+using ProgramName = std::string;
+
+static int exitStatus{EXIT_SUCCESS};
+
+// Print the module without the "module { ... }" wrapper.
+static void printModule(mlir::ModuleOp mlirModule, llvm::raw_ostream &out) {
+  for (auto &op : mlirModule.getBody()->without_terminator())
+    out << op << '\n';
+  out << '\n';
+}
+
+static void convertFortranSourceToMLIR(
+    std::string path, Fortran::parser::Options options,
+    const ProgramName &programPrefix,
+    Fortran::semantics::SemanticsContext &semanticsContext,
+    const mlir::PassPipelineCLParser &passPipeline) {
+  if (!(fixedForm || freeForm)) {
+    auto dot = path.rfind(".");
+    if (dot != std::string::npos) {
+      std::string suffix{path.substr(dot + 1)};
+      options.isFixedForm = suffix == "f" || suffix == "F" || suffix == "ff";
+    }
+  }
+  // prep for prescan and parse
+  options.searchDirectories = includeDirs;
+  Fortran::parser::Parsing parsing{semanticsContext.allSources()};
+  parsing.Prescan(path, options);
+  if (!parsing.messages().empty() &&
+      (warnIsError || parsing.messages().AnyFatalError())) {
+    llvm::errs() << programPrefix << "could not scan " << path << '\n';
+    parsing.messages().Emit(llvm::errs(), parsing.cooked());
+    exitStatus = EXIT_FAILURE;
+    return;
+  }
+
+  // parse the input Fortran
+  parsing.Parse(llvm::outs());
+  parsing.messages().Emit(llvm::errs(), parsing.cooked());
+  if (!parsing.consumedWholeFile()) {
+    parsing.EmitMessage(llvm::errs(), parsing.finalRestingPlace(),
+                        "parser FAIL (final position)");
+    exitStatus = EXIT_FAILURE;
+    return;
+  }
+  if ((!parsing.messages().empty() &&
+       (warnIsError || parsing.messages().AnyFatalError())) ||
+      !parsing.parseTree().has_value()) {
+    llvm::errs() << programPrefix << "could not parse " << path << '\n';
+    exitStatus = EXIT_FAILURE;
+    return;
+  }
+
+  // run semantics
+  auto &parseTree{*parsing.parseTree()};
+  Fortran::semantics::Semantics semantics{semanticsContext, parseTree,
+                                          parsing.cooked()};
+  semantics.Perform();
+  semantics.EmitMessages(llvm::errs());
+  if (semantics.AnyFatalError()) {
+    llvm::errs() << programPrefix << "semantic errors in " << path << '\n';
+    exitStatus = EXIT_FAILURE;
+    return;
+  }
+  if (dumpSymbols)
+    semantics.DumpSymbols(llvm::outs());
+
+  if (pftDumpTest) {
+    if (auto ast{Fortran::lower::createPFT(parseTree, semanticsContext)}) {
+      Fortran::lower::dumpPFT(llvm::outs(), *ast);
+    } else {
+      llvm::errs() << "Pre FIR Tree is NULL.\n";
+      exitStatus = EXIT_FAILURE;
+    }
+    return;
+  }
+
+  // MLIR+FIR
+  fir::NameUniquer nameUniquer;
+  auto loweringBridge = Fortran::lower::LoweringBridge::create(
+      semanticsContext.defaultKinds(), semanticsContext.intrinsics(),
+      parsing.cooked());
+  loweringBridge.lower(parseTree, nameUniquer, semanticsContext);
+  mlir::ModuleOp mlirModule = loweringBridge.getModule();
+  std::error_code ec;
+  std::string outputName = outputFilename;
+  if (!outputName.size())
+    outputName = llvm::sys::path::stem(inputFilename).str().append(".mlir");
+  llvm::raw_fd_ostream out(outputName, ec);
+  if (ec) {
+    llvm::errs() << "could not open output file " << outputName << '\n';
+    return;
+  }
+
+  printModule(mlirModule, out);
+}
+
+int main(int argc, char **argv) {
+  fir::registerFIR();
+  [[maybe_unused]] llvm::InitLLVM y(argc, argv);
+
+  mlir::registerAsmPrinterCLOptions();
+  mlir::registerMLIRContextCLOptions();
+  mlir::registerPassManagerCLOptions();
+  mlir::PassPipelineCLParser passPipe("", "Compiler passes to run");
+  llvm::cl::ParseCommandLineOptions(argc, argv, "Burnside Bridge Compiler\n");
+
+  ProgramName programPrefix;
+  programPrefix = argv[0] + ": "s;
+
+  if (includeDirs.size() == 0)
+    includeDirs.push_back(".");
+
+  if (!intrinsicModuleDir.empty()) {
+    includeDirs.insert(includeDirs.begin(), intrinsicModuleDir);
+  }
+
+  Fortran::parser::Options options;
+  options.predefinitions.emplace_back("__F18", "1");
+  options.predefinitions.emplace_back("__F18_MAJOR__", "1");
+  options.predefinitions.emplace_back("__F18_MINOR__", "1");
+  options.predefinitions.emplace_back("__F18_PATCHLEVEL__", "1");
+#if __x86_64__
+  options.predefinitions.emplace_back("__x86_64__", "1");
+#endif
+
+  Fortran::common::IntrinsicTypeDefaultKinds defaultKinds;
+  Fortran::parser::AllSources allSources;
+  Fortran::semantics::SemanticsContext semanticsContext{
+      defaultKinds, options.features, allSources};
+  semanticsContext.set_moduleDirectory(moduleDir)
+      .set_moduleFileSuffix(moduleSuffix)
+      .set_searchDirectories(includeDirs)
+      .set_warnOnNonstandardUsage(warnStdViolation)
+      .set_warningsAreErrors(warnIsError);
+
+  convertFortranSourceToMLIR(inputFilename, options, programPrefix,
+                             semanticsContext, passPipe);
+  return exitStatus;
+}