Revert#2 "[MLIR][Flang][DebugInfo] Set debug info format in MLIR->IR translation (#95098)"

Also reverts "[MLIR][Flang][DebugInfo] Convert debug format in MLIR translators"

The patch above introduces behaviour controlled by an LLVM flag into the
Flang driver, which is incorrect behaviour.

This reverts commits:
  3cc2710.
  460408f.

Author: SLTozer

flang/lib/Frontend/FrontendActions.cpp

@@ -50,7 +50,6 @@
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Bitcode/BitcodeWriterPass.h"
 #include "llvm/CodeGen/MachineOptimizationRemarkEmitter.h"
-#include "llvm/IR/DebugProgramInstruction.h"
 #include "llvm/IR/LLVMRemarkStreamer.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Verifier.h"
@@ -82,8 +81,6 @@ using namespace Fortran::frontend;
   llvm::PassPluginLibraryInfo get##Ext##PluginInfo();
 #include "llvm/Support/Extension.def"
 
-extern llvm::cl::opt<bool> WriteNewDbgInfoFormat;
-
 /// Save the given \c mlirModule to a temporary .mlir file, in a location
 /// decided by the -save-temps flag. No files are produced if the flag is not
 /// specified.
@@ -1274,13 +1271,6 @@ void CodeGenAction::executeAction() {
   runOptimizationPipeline(ci.isOutputStreamNull() ? *os : ci.getOutputStream());
 
   if (action == BackendActionTy::Backend_EmitLL) {
-    // When printing LLVM IR, we should convert the module to the debug info
-    // format that LLVM expects us to print.
-    // See https://llvm.org/docs/RemoveDIsDebugInfo.html
-    llvm::ScopedDbgInfoFormatSetter FormatSetter(*llvmModule,
-                                                 WriteNewDbgInfoFormat);
-    if (WriteNewDbgInfoFormat)
-      llvmModule->removeDebugIntrinsicDeclarations();
     llvmModule->print(ci.isOutputStreamNull() ? *os : ci.getOutputStream(),
                       /*AssemblyAnnotationWriter=*/nullptr);
     return;

mlir/lib/Target/LLVMIR/ConvertToLLVMIR.cpp

@@ -16,12 +16,9 @@
 #include "mlir/Target/LLVMIR/Dialect/All.h"
 #include "mlir/Target/LLVMIR/Export.h"
 #include "mlir/Tools/mlir-translate/Translation.h"
-#include "llvm/IR/DebugProgramInstruction.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 
-extern llvm::cl::opt<bool> WriteNewDbgInfoFormat;
-
 using namespace mlir;
 
 namespace mlir {
@@ -34,13 +31,6 @@ void registerToLLVMIRTranslation() {
         if (!llvmModule)
           return failure();
 
-        // When printing LLVM IR, we should convert the module to the debug info
-        // format that LLVM expects us to print.
-        // See https://llvm.org/docs/RemoveDIsDebugInfo.html
-        llvm::ScopedDbgInfoFormatSetter FormatSetter(*llvmModule,
-                                                     WriteNewDbgInfoFormat);
-        if (WriteNewDbgInfoFormat)
-          llvmModule->removeDebugIntrinsicDeclarations();
         llvmModule->print(output, nullptr);
         return success();
       },

mlir/lib/Target/LLVMIR/ModuleTranslation.cpp

@@ -64,8 +64,6 @@ using namespace mlir;
 using namespace mlir::LLVM;
 using namespace mlir::LLVM::detail;
 
-extern llvm::cl::opt<bool> UseNewDbgInfoFormat;
-
 #include "mlir/Dialect/LLVMIR/LLVMConversionEnumsToLLVM.inc"
 
 namespace {
@@ -1791,9 +1789,6 @@ prepareLLVMModule(Operation *m, llvm::LLVMContext &llvmContext,
                   StringRef name) {
   m->getContext()->getOrLoadDialect<LLVM::LLVMDialect>();
   auto llvmModule = std::make_unique<llvm::Module>(name, llvmContext);
-  // ModuleTranslation can currently only construct modules in the old debug
-  // info format, so set the flag accordingly.
-  llvmModule->setNewDbgInfoFormatFlag(false);
   if (auto dataLayoutAttr =
           m->getDiscardableAttr(LLVM::LLVMDialect::getDataLayoutAttrName())) {
     llvmModule->setDataLayout(cast<StringAttr>(dataLayoutAttr).getValue());
@@ -1872,11 +1867,6 @@ mlir::translateModuleToLLVMIR(Operation *module, llvm::LLVMContext &llvmContext,
   if (failed(translator.convertFunctions()))
     return nullptr;
 
-  // Once we've finished constructing elements in the module, we should convert
-  // it to use the debug info format desired by LLVM.
-  // See https://llvm.org/docs/RemoveDIsDebugInfo.html
-  translator.llvmModule->setIsNewDbgInfoFormat(UseNewDbgInfoFormat);
-
   if (!disableVerification &&
       llvm::verifyModule(*translator.llvmModule, &llvm::errs()))
     return nullptr;

mlir/test/lib/Dialect/Test/TestToLLVMIRTranslation.cpp

@@ -22,9 +22,6 @@
 #include "mlir/Tools/mlir-translate/Translation.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/ADT/TypeSwitch.h"
-#include "llvm/IR/DebugProgramInstruction.h"
-
-extern llvm::cl::opt<bool> WriteNewDbgInfoFormat;
 
 using namespace mlir;
 
@@ -125,13 +122,6 @@ void registerTestToLLVMIR() {
         if (!llvmModule)
           return failure();
 
-        // When printing LLVM IR, we should convert the module to the debug info
-        // format that LLVM expects us to print.
-        // See https://llvm.org/docs/RemoveDIsDebugInfo.html
-        llvm::ScopedDbgInfoFormatSetter FormatSetter(*llvmModule,
-                                                     WriteNewDbgInfoFormat);
-        if (WriteNewDbgInfoFormat)
-          llvmModule->removeDebugIntrinsicDeclarations();
         llvmModule->print(output, nullptr);
         return success();
       },