[mlir][Translation] Make commandline option registration optional

[rkayaith]

Summary

This moves the commandline option registration into its own function, so
that users can register translations without registering the options.

[Peiming]

mlir/lib/Tools/mlir-translate/Translation.cpp

120–121

Don't you need to test clOptions.isConstructed() before you can use it?

[cota]

mlir/lib/Tools/mlir-translate/Translation.cpp

120–121

Doesn't seem necessary from my reading of the source:

Pointer dereference accessor:

C *operator->() { return &**this; }

which then uses this accessor that constructs the object if necessary:

C &operator*() {
  void *Tmp = Ptr.load(std::memory_order_acquire);
  if (!Tmp)
    RegisterManagedStatic(Creator::call, Deleter::call);

  return *static_cast<C *>(Ptr.load(std::memory_order_relaxed));
}

[cota]

mlir/lib/Tools/mlir-translate/Translation.cpp

120–121

https://github.com/llvm-mirror/llvm/blob/2c4ca6832fa6b306ee6a7010bfb80a3f2596f824/include/llvm/Support/ManagedStatic.h#L94

[Peiming]

mlir/lib/Tools/mlir-translate/Translation.cpp

120–121

Does it mean that operator-> will implicit register the option? if that is the case, it does not solve our problem.

[cota]

mlir/lib/Tools/mlir-translate/Translation.cpp

120–121

I talked to Peiming and understood his comment better.
Peiming is right; the problem here is that by dereferencing the options, we are constructing them (and therefore registering them), which defeats the purpose of the patch (i.e. to not register the options). So this cannot proceed as is.

[rkayaith]

mlir/lib/Tools/mlir-translate/Translation.cpp

120–121

Yea we want to avoid constructing the cl options object here, so I'll update this to check isConstructed.

[rkayaith]

rebase, avoid construction options

mlir/include/mlir/Tools/mlir-translate/Translation.h

 /// A command line parser for translation functions.
 struct TranslationParser : public llvm::cl::parser<const TranslateFunction *> {
   TranslationParser(llvm::cl::Option &opt);
 
   void printOptionInfo(const llvm::cl::Option &o,
                        size_t globalWidth) const override;
 };
 
+/// Register command-line options used by the translation registry.
+void registerTranslationCLOptions();
+
 } // namespace mlir
 
 #endif // MLIR_TOOLS_MLIRTRANSLATE_TRANSLATION_H

mlir/lib/Tools/mlir-translate/MlirTranslateMain.cpp

LogicalResult mlir::mlirTranslateMain(int argc, char **argv,
   llvm::InitLLVM y(argc, argv);
 
   // Add flags for all the registered translations.
   llvm::cl::opt<const TranslateFunction *, false, TranslationParser>
       translationRequested("", llvm::cl::desc("Translation to perform"),
                            llvm::cl::Required);
   registerAsmPrinterCLOptions();
   registerMLIRContextCLOptions();
+  registerTranslationCLOptions();
   llvm::cl::ParseCommandLineOptions(argc, argv, toolName);
 
   std::string errorMessage;
   auto input = openInputFile(inputFilename, &errorMessage);
   if (!input) {
     llvm::errs() << errorMessage << "\n";
     return failure();
   }

mlir/lib/Tools/mlir-translate/Translation.cpp

 #include "mlir/IR/Verifier.h"
 #include "mlir/Parser/Parser.h"
 #include "mlir/Tools/ParseUtilties.h"
 #include "llvm/Support/SourceMgr.h"
 
 using namespace mlir;
 
 //===----------------------------------------------------------------------===//
+// Translation CommandLine Options
+//===----------------------------------------------------------------------===//
+
+struct TranslationOptions {
+  llvm::cl::opt<bool> noImplicitModule{
+      "no-implicit-module",
+      llvm::cl::desc("Disable the parsing of an implicit top-level module op"),
+      llvm::cl::init(false)};
+};
+
+static llvm::ManagedStatic<TranslationOptions> clOptions;
+
+void mlir::registerTranslationCLOptions() { *clOptions; }
+
+//===----------------------------------------------------------------------===//
 // Translation Registry
 //===----------------------------------------------------------------------===//
 
 struct TranslationBundle {
   TranslateFunction translateFunction;
   StringRef translateDescription;
 };
 

 //===----------------------------------------------------------------------===//
 // Translation from MLIR
 //===----------------------------------------------------------------------===//
 
 TranslateFromMLIRRegistration::TranslateFromMLIRRegistration(
     StringRef name, StringRef description,
     const TranslateFromMLIRFunction &function,
     const std::function<void(DialectRegistry &)> &dialectRegistration) {
 
-  static llvm::cl::opt<bool> noImplicitModule{
-      "no-implicit-module",
-      llvm::cl::desc("Disable the parsing of an implicit top-level module op"),
-      llvm::cl::init(false)};
-
-  registerTranslation(name, description,
-                      [function, dialectRegistration](
-                          llvm::SourceMgr &sourceMgr, raw_ostream &output,
+  registerTranslation(
+      name, description,
+      [function, dialectRegistration](llvm::SourceMgr &sourceMgr,
+                                      raw_ostream &output,
                                       MLIRContext *context) {
-                        DialectRegistry registry;
-                        dialectRegistration(registry);
-                        context->appendDialectRegistry(registry);
-                        OwningOpRef<Operation *> op = parseSourceFileForTool(
-                            sourceMgr, context, !noImplicitModule);
-                        if (!op || failed(verify(*op)))
-                          return failure();
-                        return function(op.get(), output);
-                      });
+        bool implicitModule =
+            (!clOptions.isConstructed() || !clOptions->noImplicitModule);
+        OwningOpRef<Operation *> op =
+            parseSourceFileForTool(sourceMgr, context, implicitModule);
 }
 
 //===----------------------------------------------------------------------===//
 // Translation Parser
 //===----------------------------------------------------------------------===//
 
 TranslationParser::TranslationParser(llvm::cl::Option &opt)
     : llvm::cl::parser<const TranslateFunction *>(opt) {