[MLIR][LLVM] Debug info: import debug records directly (#167812)

Effectively means we don't need to call into
`llvmModule->convertFromNewDbgValues()` anymore. Added a flag to allow
users to access the old behavior.

Author: bcardosolopes

mlir/include/mlir/Target/LLVMIR/ModuleImport.h

@@ -163,9 +163,10 @@ class ModuleImport {
   /// Converts `value` to a float attribute. Asserts if the matching fails.
   FloatAttr matchFloatAttr(llvm::Value *value);
 
-  /// Converts `value` to a local variable attribute. Asserts if the matching
-  /// fails.
-  DILocalVariableAttr matchLocalVariableAttr(llvm::Value *value);
+  /// Converts `valOrVariable` to a local variable attribute. Asserts if the
+  /// matching fails.
+  DILocalVariableAttr matchLocalVariableAttr(
+      llvm::PointerUnion<llvm::Value *, llvm::DILocalVariable *> valOrVariable);
 
   /// Converts `value` to a label attribute. Asserts if the matching fails.
   DILabelAttr matchLabelAttr(llvm::Value *value);
@@ -281,6 +282,9 @@ class ModuleImport {
   /// after the function conversion has finished.
   void addDebugIntrinsic(llvm::CallInst *intrinsic);
 
+  /// Similar to `addDebugIntrinsic`, but for debug records.
+  void addDebugRecord(llvm::DbgRecord *debugRecord);
+
   /// Converts the LLVM values for an intrinsic to mixed MLIR values and
   /// attributes for LLVM_IntrOpBase. Attributes correspond to LLVM immargs. The
   /// list `immArgPositions` contains the positions of immargs on the LLVM
@@ -339,9 +343,26 @@ class ModuleImport {
   /// Converts all debug intrinsics in `debugIntrinsics`. Assumes that the
   /// function containing the intrinsics has been fully converted to MLIR.
   LogicalResult processDebugIntrinsics();
+  /// Converts all debug records in `debugRecords`. Assumes that the
+  /// function containing the record has been fully converted to MLIR.
+  LogicalResult processDebugRecords();
   /// Converts a single debug intrinsic.
   LogicalResult processDebugIntrinsic(llvm::DbgVariableIntrinsic *dbgIntr,
                                       DominanceInfo &domInfo);
+  /// Converts a single debug record.
+  LogicalResult processDebugRecord(llvm::DbgRecord &debugRecord,
+                                   DominanceInfo &domInfo);
+  /// Process arguments for declare/value operation insertion. `localVarAttr`
+  /// and `localExprAttr` are the attained attributes after importing the debug
+  /// variable and expressions. This also sets the builder insertion point to be
+  /// used by these operations.
+  std::tuple<DILocalVariableAttr, DIExpressionAttr, Value>
+  processDebugOpArgumentsAndInsertionPt(
+      Location loc, bool hasArgList, bool isKillLocation,
+      llvm::function_ref<FailureOr<Value>()> convertArgOperandToValue,
+      llvm::Value *address,
+      llvm::PointerUnion<llvm::Value *, llvm::DILocalVariable *> variable,
+      llvm::DIExpression *expression, DominanceInfo &domInfo);
   /// Converts LLMV IR asm inline call operand's attributes into an array of
   /// MLIR attributes to be utilized in `llvm.inline_asm`.
   ArrayAttr convertAsmInlineOperandAttrs(const llvm::CallBase &llvmCall);
@@ -485,6 +506,9 @@ class ModuleImport {
   /// Function-local list of debug intrinsics that need to be imported after the
   /// function conversion has finished.
   SetVector<llvm::Instruction *> debugIntrinsics;
+  /// Function-local list of debug records that need to be imported after the
+  /// function conversion has finished.
+  SetVector<llvm::DbgRecord *> debugRecords;
   /// Mapping between LLVM alias scope and domain metadata nodes and
   /// attributes in the LLVM dialect corresponding to these nodes.
   DenseMap<const llvm::MDNode *, Attribute> aliasScopeMapping;

mlir/lib/Target/LLVMIR/ConvertFromLLVMIR.cpp

@@ -30,6 +30,14 @@ void registerFromLLVMIRTranslation() {
       llvm::cl::desc("Emit expensive warnings during LLVM IR import "
                      "(discouraged: testing only!)"),
       llvm::cl::init(false));
+  static llvm::cl::opt<bool> convertDebugRecToIntrinsics(
+      "convert-debug-rec-to-intrinsics",
+      llvm::cl::desc("Change the input LLVM module to use old debug intrinsics "
+                     "instead of records "
+                     "via convertFromNewDbgValues, this happens "
+                     "before importing the debug information"
+                     "(discouraged: to be removed soon!)"),
+      llvm::cl::init(false));
   static llvm::cl::opt<bool> dropDICompositeTypeElements(
       "drop-di-composite-type-elements",
       llvm::cl::desc(
@@ -69,8 +77,10 @@ void registerFromLLVMIRTranslation() {
         if (llvm::verifyModule(*llvmModule, &llvm::errs()))
           return nullptr;
 
-        // Debug records are not currently supported in the LLVM IR translator.
-        llvmModule->convertFromNewDbgValues();
+        // Now that the translation supports importing debug records directly,
+        // make it the default, but allow the user to override to old behavior.
+        if (!convertDebugRecToIntrinsics)
+          llvmModule->convertFromNewDbgValues();
 
         return translateLLVMIRToModule(
             std::move(llvmModule), context, emitExpensiveWarnings,