message: More logging in poplar_compiler
  Summary: Ref T16509
  Reviewers: #tensorflow, #framework_ip_review_-_any_oss_or_third-party_code_use_has_been_approved, davidn
  Maniphest Tasks: T16509
diff: @@ -616,7 +616,7 @@ StatusOr<std::unique_ptr<Executable>> PoplarCompiler::RunBackend(
  std::call_once(help_flag_printed, &PrintHelpString);
  }
  - VLOG(1) << "Begin compilation: " << module->name() << " " << std::hex
  + VLOG(1) << "Begin XLA compilation: " << module->name() << " " << std::hex
  << " (Hash: 0x" << HloHash(module.get()).GetHash() << std::dec
  << ") for ordinal " << stream_exec->device_ordinal();
  @@ -881,6 +881,9 @@ StatusOr<std::unique_ptr<Executable>> PoplarCompiler::RunBackend(
  TF_RETURN_IF_ERROR(pipeline.Run(module.get()).status());
  }
  + VLOG(1) << "End XLA compilation: " << module->name() << " (Hash: 0x"
  + << std::hex << HloHash(module.get()).GetHash() << ")";
  +
  HloComputation* entry = module->entry_computation();
  // Set layout if there isn't one
  @@ -961,10 +964,11 @@ StatusOr<std::unique_ptr<Executable>> PoplarCompiler::RunBackend(
  CreatePoplarGraphs(resources, module.get(), poplar_executor));
  auto& main_graph = GetMasterGraph(resources);
  + try {
  + VLOG(1) << "Preplanning of Poplar operations.";
  +
  EmbeddingPlansPreplanning embeddings_preplanning;
  TF_RETURN_IF_ERROR(embeddings_preplanning.Plan(module.get(), resources));
  -
  - try {
  ConvolutionPreplanning convolution_preplanning;
  TF_RETURN_IF_ERROR(convolution_preplanning.Plan(module.get(), resources));
  MatMulPreplanning matmul_preplanning;
  @@ -975,7 +979,9 @@ StatusOr<std::unique_ptr<Executable>> PoplarCompiler::RunBackend(
  resources, poplar_executor->VerifiedTransfers()));
  // The following line starts the lowering in poplar.
  + VLOG(1) << "Begin Poplar graph contruction.";
  TF_RETURN_IF_ERROR(entry->AcceptOrdered(&visitor, order));
  + VLOG(1) << "End Poplar graph contruction.";
  } catch (const std::exception& e) {
  return PoplarExceptionToTensorflowStatus("[Build graph] ", e);
  }
  @@ -1021,7 +1027,7 @@ StatusOr<std::unique_ptr<Executable>> PoplarCompiler::RunBackend(
  }
  try {
  - VLOG(1) << "Compile engine " << module->name();
  + VLOG(1) << "Begin compiling Poplar engine " << module->name();
  map_json = GetTensorMappingJson(module->name(), main_graph,
  resources.tensor_maps);
  @@ -1058,6 +1064,7 @@ StatusOr<std::unique_ptr<Executable>> PoplarCompiler::RunBackend(
  }
  engine.reset(new poplar::Engine(std::move(exec), opts));
  + VLOG(1) << "End compiling Poplar engine.";
  } catch (const std::exception& e) {
  if (poplar_executor->CompilerReportingEnabled()) {
  @@ -1123,9 +1130,6 @@ StatusOr<std::unique_ptr<Executable>> PoplarCompiler::RunBackend(
  module->name(), report_stream.str(), map_json, inst_info, duration);
  }
  - VLOG(1) << "End compilation: " << module->name() << " (Hash: 0x" << std::hex
  - << HloHash(module.get()).GetHash() << ")";
  -
  std::unique_ptr<Executable> executable;
  PoplarExecutable* poplar_executable = new PoplarExecutable(
  std::move(module), std::move(profile_printer),
  