llvm · gysit · Feb 23, 2024 · Feb 22, 2024
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
@@ -513,7 +513,11 @@ def LLVM_DbgLabelOp : LLVM_IntrOp<"dbg.label", [], [], [], 0> {
       });
   }];
   let mlirBuilder = [{
-    $_op = $_builder.create<$_qualCppClassName>($_location, $_label_attr($label));
+    DILabelAttr labelAttr = $_label_attr($label);
+    // Drop the intrinsic if the label translation fails due to cylic metadata.
+    if (!labelAttr)
+      return success();
+    $_op = $_builder.create<$_qualCppClassName>($_location, labelAttr);
   }];
   let assemblyFormat = "$label attr-dict";
 }

diff --git a/mlir/lib/Target/LLVMIR/DebugImporter.cpp b/mlir/lib/Target/LLVMIR/DebugImporter.cpp
@@ -99,21 +99,31 @@ DIFileAttr DebugImporter::translateImpl(llvm::DIFile *node) {
 }
 
 DILabelAttr DebugImporter::translateImpl(llvm::DILabel *node) {
-  return DILabelAttr::get(context, translate(node->getScope()),
+  // Return nullptr if the scope or type is a cyclic dependency.
+  DIScopeAttr scope = translate(node->getScope());
+  if (node->getScope() && !scope)
+    return nullptr;
+  return DILabelAttr::get(context, scope,
                           getStringAttrOrNull(node->getRawName()),
                           translate(node->getFile()), node->getLine());
 }
 
 DILexicalBlockAttr DebugImporter::translateImpl(llvm::DILexicalBlock *node) {
-  return DILexicalBlockAttr::get(context, translate(node->getScope()),
-                                 translate(node->getFile()), node->getLine(),
-                                 node->getColumn());
+  // Return nullptr if the scope or type is a cyclic dependency.
+  DIScopeAttr scope = translate(node->getScope());
+  if (node->getScope() && !scope)
+    return nullptr;
+  return DILexicalBlockAttr::get(context, scope, translate(node->getFile()),
+                                 node->getLine(), node->getColumn());
 }
 
 DILexicalBlockFileAttr
 DebugImporter::translateImpl(llvm::DILexicalBlockFile *node) {
-  return DILexicalBlockFileAttr::get(context, translate(node->getScope()),
-                                     translate(node->getFile()),
+  // Return nullptr if the scope or type is a cyclic dependency.
+  DIScopeAttr scope = translate(node->getScope());
+  if (node->getScope() && !scope)
+    return nullptr;
+  return DILexicalBlockFileAttr::get(context, scope, translate(node->getFile()),
                                      node->getDiscriminator());
 }
 
@@ -135,11 +145,14 @@ DebugImporter::translateImpl(llvm::DIGlobalVariable *node) {
 }
 
 DILocalVariableAttr DebugImporter::translateImpl(llvm::DILocalVariable *node) {
-  return DILocalVariableAttr::get(context, translate(node->getScope()),
-                                  getStringAttrOrNull(node->getRawName()),
-                                  translate(node->getFile()), node->getLine(),
-                                  node->getArg(), node->getAlignInBits(),
-                                  translate(node->getType()));
+  // Return nullptr if the scope or type is a cyclic dependency.
+  DIScopeAttr scope = translate(node->getScope());
+  if (node->getScope() && !scope)
+    return nullptr;
+  return DILocalVariableAttr::get(
+      context, scope, getStringAttrOrNull(node->getRawName()),
+      translate(node->getFile()), node->getLine(), node->getArg(),
+      node->getAlignInBits(), translate(node->getType()));
 }
 
 DIScopeAttr DebugImporter::translateImpl(llvm::DIScope *node) {

diff --git a/mlir/lib/Target/LLVMIR/ModuleImport.cpp b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
@@ -1966,6 +1966,13 @@ ModuleImport::processDebugIntrinsic(llvm::DbgVariableIntrinsic *dbgIntr,
   // TODO: find a way to support this case.
   if (isMetadataKillLocation(dbgIntr))
     return emitUnsupportedWarning();
+  // Drop debug intrinsics if the associated variable information cannot be
+  // translated due to cyclic debug metadata.
+  // TODO: Support cyclic debug metadata.
+  DILocalVariableAttr localVariableAttr =
+      matchLocalVariableAttr(dbgIntr->getArgOperand(1));
+  if (!localVariableAttr)
+    return emitUnsupportedWarning();
   FailureOr<Value> argOperand = convertMetadataValue(dbgIntr->getArgOperand(0));
   if (failed(argOperand))
     return emitError(loc) << "failed to convert a debug intrinsic operand: "
@@ -1991,8 +1998,6 @@ ModuleImport::processDebugIntrinsic(llvm::DbgVariableIntrinsic *dbgIntr,
   } else {
     builder.setInsertionPointAfterValue(*argOperand);
   }
-  DILocalVariableAttr localVariableAttr =
-      matchLocalVariableAttr(dbgIntr->getArgOperand(1));
   auto locationExprAttr =
       debugImporter->translateExpression(dbgIntr->getExpression());
   Operation *op =

diff --git a/mlir/test/Target/LLVMIR/Import/import-failure.ll b/mlir/test/Target/LLVMIR/Import/import-failure.ll
@@ -59,13 +59,15 @@ define void @unhandled_intrinsic() gc "example" {
 
 ; // -----
 
+; Check that debug intrinsics with an unsupported argument are dropped.
+
 declare void @llvm.dbg.value(metadata, metadata, metadata)
 
 ; CHECK:      import-failure.ll
-; CHECK-SAME: warning: dropped intrinsic: call void @llvm.dbg.value(metadata !DIArgList(i64 %arg1, i64 undef), metadata !3, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_constu, 1, DW_OP_mul, DW_OP_plus, DW_OP_stack_value)), !dbg !5
+; CHECK-SAME: warning: dropped intrinsic: call void @llvm.dbg.value(metadata !DIArgList(i64 %{{.*}}, i64 undef), metadata !3, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_constu, 1, DW_OP_mul, DW_OP_plus, DW_OP_stack_value))
 ; CHECK:      import-failure.ll
-; CHECK-SAME: warning: dropped intrinsic: call void @llvm.dbg.value(metadata !6, metadata !3, metadata !DIExpression()), !dbg !5
-define void @dropped_instruction(i64 %arg1) {
+; CHECK-SAME: warning: dropped intrinsic: call void @llvm.dbg.value(metadata !6, metadata !3, metadata !DIExpression())
+define void @unsupported_argument(i64 %arg1) {
   call void @llvm.dbg.value(metadata !DIArgList(i64 %arg1, i64 undef), metadata !3, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_constu, 1, DW_OP_mul, DW_OP_plus, DW_OP_stack_value)), !dbg !5
   call void @llvm.dbg.value(metadata !6, metadata !3, metadata !DIExpression()), !dbg !5
   ret void
@@ -83,6 +85,38 @@ define void @dropped_instruction(i64 %arg1) {
 
 ; // -----
 
+; Check that debug intrinsics that depend on cyclic metadata are dropped.
+
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+; CHECK:      import-failure.ll
+; CHECK-SAME: warning: dropped instruction: call void @llvm.dbg.label(metadata !{{.*}})
+; CHECK:      import-failure.ll
+; CHECK-SAME: warning: dropped intrinsic: call void @llvm.dbg.value(metadata i64 %{{.*}}, metadata !3, metadata !DIExpression())
+define void @cylic_metadata(i64 %arg1) {
+  call void @llvm.dbg.value(metadata i64 %arg1, metadata !10, metadata !DIExpression()), !dbg !14
+  call void @llvm.dbg.label(metadata !13), !dbg !14
+  ret void
+}
+
+!llvm.dbg.cu = !{!1}
+!llvm.module.flags = !{!0}
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = distinct !DICompileUnit(language: DW_LANG_C, file: !2)
+!2 = !DIFile(filename: "import-failure.ll", directory: "/")
+!3 = !DICompositeType(tag: DW_TAG_array_type, size: 42, baseType: !4)
+!4 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !3)
+!5 = distinct !DISubprogram(name: "class_method", scope: !2, file: !2, type: !6, spFlags: DISPFlagDefinition, unit: !1)
+!6 = !DISubroutineType(types: !7)
+!7 = !{!3}
+!10 = !DILocalVariable(scope: !5, name: "arg1", file: !2, line: 1, arg: 1, align: 64);
+!11 = !DILexicalBlock(scope: !5)
+!12 = !DILexicalBlockFile(scope: !11, discriminator: 0)
+!13 = !DILabel(scope: !12, name: "label", file: !2, line: 42)
+!14 = !DILocation(line: 1, column: 2, scope: !5)
+
+; // -----
+
 ; global_dtors with non-null data fields cannot be represented in MLIR.
 ; CHECK:      <unknown>
 ; CHECK-SAME: error: unhandled global variable: @llvm.global_dtors