[mlir] Add importedEntities field in DIComplileUnitAttr. by abidh · Pull Request #188576 · llvm/llvm-project

abidh · 2026-03-25T19:42:17Z

Mostly mechanical changes to add the missing field. It can help when importing something at non-local level like Fortran modules or C++ namespaces.

llvmbot · 2026-03-25T19:42:54Z

@llvm/pr-subscribers-mlir-llvm

@llvm/pr-subscribers-mlir

Author: Abid Qadeer (abidh)

Changes

Mostly mechanical changes to add the missing field. It can help when importing something at non-local level like Fortran modules or C++ namespaces.

Full diff: https://github.com/llvm/llvm-project/pull/188576.diff

8 Files Affected:

(modified) mlir/include/mlir-c/Dialect/LLVM.h (+2-1)
(modified) mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td (+6-3)
(modified) mlir/lib/CAPI/Dialect/LLVM.cpp (+8-2)
(modified) mlir/lib/Target/LLVMIR/DebugImporter.cpp (+8-1)
(modified) mlir/lib/Target/LLVMIR/DebugTranslation.cpp (+9-1)
(modified) mlir/test/CAPI/llvm.c (+1-1)
(modified) mlir/test/Target/LLVMIR/Import/debug-info.ll (+23)
(modified) mlir/test/Target/LLVMIR/llvmir-debug.mlir (+30)

diff --git a/mlir/include/mlir-c/Dialect/LLVM.h b/mlir/include/mlir-c/Dialect/LLVM.h
index 4c359b17f7e14..993f85ace1cf2 100644
--- a/mlir/include/mlir-c/Dialect/LLVM.h
+++ b/mlir/include/mlir-c/Dialect/LLVM.h
@@ -344,7 +344,8 @@ MLIR_CAPI_EXPORTED MlirAttribute mlirLLVMDICompileUnitAttrGet(
     MlirContext ctx, MlirAttribute id, unsigned int sourceLanguage,
     MlirAttribute file, MlirAttribute producer, bool isOptimized,
     MlirLLVMDIEmissionKind emissionKind, MlirLLVMDINameTableKind nameTableKind,
-    MlirAttribute splitDebugFilename);
+    MlirAttribute splitDebugFilename, intptr_t nImportedEntities,
+    MlirAttribute const *importedEntities);
 
 MLIR_CAPI_EXPORTED MlirStringRef mlirLLVMDICompileUnitAttrGetName(void);
 
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
index 36acf244865eb..e10818bad56d6 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
@@ -426,7 +426,8 @@ def LLVM_DICompileUnitAttr : LLVM_Attr<"DICompileUnit", "di_compile_unit",
     "bool":$isOptimized,
     "DIEmissionKind":$emissionKind,
     OptionalParameter<"DINameTableKind">:$nameTableKind,
-    OptionalParameter<"StringAttr">:$splitDebugFilename
+    OptionalParameter<"StringAttr">:$splitDebugFilename,
+    OptionalArrayRefParameter<"DINodeAttr">:$importedEntities
   );
   let builders = [
     AttrBuilderWithInferredContext<(ins
@@ -434,10 +435,12 @@ def LLVM_DICompileUnitAttr : LLVM_Attr<"DICompileUnit", "di_compile_unit",
       "StringAttr":$producer, "bool":$isOptimized,
       "DIEmissionKind":$emissionKind,
       CArg<"DINameTableKind", "DINameTableKind::Default">:$nameTableKind,
-      CArg<"StringAttr", "{}">:$splitDebugFilename
+      CArg<"StringAttr", "{}">:$splitDebugFilename,
+      CArg<"ArrayRef<DINodeAttr>", "{}">:$importedEntities
     ), [{
       return $_get(id.getContext(), id, sourceLanguage, file, producer,
-                   isOptimized, emissionKind, nameTableKind, splitDebugFilename);
+                   isOptimized, emissionKind, nameTableKind, splitDebugFilename,
+                   importedEntities);
     }]>
   ];
   let assemblyFormat = "`<` struct(params) `>`";
diff --git a/mlir/lib/CAPI/Dialect/LLVM.cpp b/mlir/lib/CAPI/Dialect/LLVM.cpp
index ce5c111b048e4..2e031bae3aa8d 100644
--- a/mlir/lib/CAPI/Dialect/LLVM.cpp
+++ b/mlir/lib/CAPI/Dialect/LLVM.cpp
@@ -322,12 +322,18 @@ MlirAttribute mlirLLVMDICompileUnitAttrGet(
     MlirContext ctx, MlirAttribute id, unsigned int sourceLanguage,
     MlirAttribute file, MlirAttribute producer, bool isOptimized,
     MlirLLVMDIEmissionKind emissionKind, MlirLLVMDINameTableKind nameTableKind,
-    MlirAttribute splitDebugFilename) {
+    MlirAttribute splitDebugFilename, intptr_t nImportedEntities,
+    MlirAttribute const *importedEntities) {
+  SmallVector<Attribute> importsStorage;
+  importsStorage.reserve(nImportedEntities);
   return wrap(DICompileUnitAttr::get(
       unwrap(ctx), cast<DistinctAttr>(unwrap(id)), sourceLanguage,
       cast<DIFileAttr>(unwrap(file)), cast<StringAttr>(unwrap(producer)),
       isOptimized, DIEmissionKind(emissionKind), DINameTableKind(nameTableKind),
-      cast<StringAttr>(unwrap(splitDebugFilename))));
+      cast<StringAttr>(unwrap(splitDebugFilename)),
+      llvm::map_to_vector(
+          unwrapList(nImportedEntities, importedEntities, importsStorage),
+          llvm::CastTo<DINodeAttr>)));
 }
 
 MlirStringRef mlirLLVMDICompileUnitAttrGetName(void) {
diff --git a/mlir/lib/Target/LLVMIR/DebugImporter.cpp b/mlir/lib/Target/LLVMIR/DebugImporter.cpp
index 37140e3a949c7..713fefc7a1f9c 100644
--- a/mlir/lib/Target/LLVMIR/DebugImporter.cpp
+++ b/mlir/lib/Target/LLVMIR/DebugImporter.cpp
@@ -57,12 +57,19 @@ DICompileUnitAttr DebugImporter::translateImpl(llvm::DICompileUnit *node) {
       static_cast<
           std::underlying_type_t<llvm::DICompileUnit::DebugNameTableKind>>(
           node->getNameTableKind()));
+  SmallVector<DINodeAttr> imports;
+  if (node->getImportedEntities()) {
+    for (llvm::DIImportedEntity *ie : node->getImportedEntities()) {
+      if (DINodeAttr na = translate(static_cast<llvm::DINode *>(ie)))
+        imports.push_back(na);
+    }
+  }
   return DICompileUnitAttr::get(
       context, getOrCreateDistinctID(node),
       node->getSourceLanguage().getUnversionedName(),
       translate(node->getFile()), getStringAttrOrNull(node->getRawProducer()),
       node->isOptimized(), emissionKind.value(), nameTableKind.value(),
-      getStringAttrOrNull(node->getRawSplitDebugFilename()));
+      getStringAttrOrNull(node->getRawSplitDebugFilename()), imports);
 }
 
 DICompositeTypeAttr DebugImporter::translateImpl(llvm::DICompositeType *node) {
diff --git a/mlir/lib/Target/LLVMIR/DebugTranslation.cpp b/mlir/lib/Target/LLVMIR/DebugTranslation.cpp
index 08eee68c195db..411335ee8e873 100644
--- a/mlir/lib/Target/LLVMIR/DebugTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/DebugTranslation.cpp
@@ -121,7 +121,7 @@ llvm::DIBasicType *DebugTranslation::translateImpl(DIBasicTypeAttr attr) {
 
 llvm::DICompileUnit *DebugTranslation::translateImpl(DICompileUnitAttr attr) {
   llvm::DIBuilder builder(llvmModule);
-  return builder.createCompileUnit(
+  llvm::DICompileUnit *cu = builder.createCompileUnit(
       attr.getSourceLanguage(), translate(attr.getFile()),
       attr.getProducer() ? attr.getProducer().getValue() : "",
       attr.getIsOptimized(),
@@ -133,6 +133,14 @@ llvm::DICompileUnit *DebugTranslation::translateImpl(DICompileUnitAttr attr) {
       0, true, false,
       static_cast<llvm::DICompileUnit::DebugNameTableKind>(
           attr.getNameTableKind()));
+
+  llvm::SmallVector<llvm::Metadata *> importNodes;
+  for (DINodeAttr n : attr.getImportedEntities())
+    importNodes.push_back(translate(n));
+  if (!importNodes.empty())
+    cu->replaceImportedEntities(llvm::MDTuple::get(llvmCtx, importNodes));
+
+  return cu;
 }
 
 /// Returns a new `DINodeT` that is either distinct or not, depending on
diff --git a/mlir/test/CAPI/llvm.c b/mlir/test/CAPI/llvm.c
index 922491a1f39d6..13b560371d9c9 100644
--- a/mlir/test/CAPI/llvm.c
+++ b/mlir/test/CAPI/llvm.c
@@ -270,7 +270,7 @@ static void testDebugInfoAttributes(MlirContext ctx) {
 
   MlirAttribute compile_unit = mlirLLVMDICompileUnitAttrGet(
       ctx, id, LLVMDWARFSourceLanguageC99, file, foo, false,
-      MlirLLVMDIEmissionKindFull, MlirLLVMDINameTableKindDefault, bar);
+      MlirLLVMDIEmissionKindFull, MlirLLVMDINameTableKindDefault, bar, 0, NULL);
 
   // CHECK: #llvm.di_compile_unit<{{.*}}>
   mlirAttributeDump(compile_unit);
diff --git a/mlir/test/Target/LLVMIR/Import/debug-info.ll b/mlir/test/Target/LLVMIR/Import/debug-info.ll
index 3c2691217e0bf..f365ea50a44c2 100644
--- a/mlir/test/Target/LLVMIR/Import/debug-info.ll
+++ b/mlir/test/Target/LLVMIR/Import/debug-info.ll
@@ -823,6 +823,29 @@ define void @imp_fn() !dbg !12 {
 
 ; // -----
 
+; CHECK-DAG: #[[M:.+]] = #llvm.di_module<{{.*}}name = "mod1"{{.*}}>
+; CHECK-DAG: #[[IE:.+]] = #llvm.di_imported_entity<tag = DW_TAG_imported_module{{.*}}entity = #[[M]]{{.*}}>
+; CHECK-DAG: #llvm.di_compile_unit<{{.*}}importedEntities = #[[IE]]>
+
+define void @compile_unit_imports() !dbg !4 {
+  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, imports: !5)
+!2 = !DIFile(filename: "debug-info.ll", directory: "/")
+!3 = !DISubroutineType(types: !8)
+!4 = distinct !DISubprogram(name: "compile_unit_imports", linkageName: "compile_unit_imports", scope: !2, file: !2, line: 1, type: !3, scopeLine: 1, spFlags: DISPFlagDefinition, unit: !1)
+!5 = !{!6}
+!6 = !DIImportedEntity(tag: DW_TAG_imported_module, scope: !2, entity: !7)
+!7 = !DIModule(scope: !2, name: "mod1", line: 5)
+!8 = !{}
+
+; // -----
+
 ; Test that annotations are handled correctly
 
 ; CHECK-LABEL: @fn_with_annotations
diff --git a/mlir/test/Target/LLVMIR/llvmir-debug.mlir b/mlir/test/Target/LLVMIR/llvmir-debug.mlir
index 1aa6362fc42d3..a579a2adb5857 100644
--- a/mlir/test/Target/LLVMIR/llvmir-debug.mlir
+++ b/mlir/test/Target/LLVMIR/llvmir-debug.mlir
@@ -740,3 +740,33 @@ llvm.mlir.global @data() {dbg_exprs = [#var_expression, #var_expression1]} : i64
 // CHECK: ![[VAR1]] = {{.*}}!DIGlobalVariable(name: "a"{{.*}})
 // CHECK: ![[EXP2]] = !DIGlobalVariableExpression(var: ![[VAR2:[0-9]+]], expr: !DIExpression())
 // CHECK: ![[VAR2]] = {{.*}}!DIGlobalVariable(name: "b"{{.*}})
+
+// -----
+
+// Test lowering compile unit `importedEntities` to LLVM IR `imports`.
+
+#file = #llvm.di_file<"test.mlir" in "">
+#ns = #llvm.di_namespace<name = "imported_ns", exportSymbols = false>
+#ie = #llvm.di_imported_entity<tag = DW_TAG_imported_module, scope = #file, entity = #ns, file = #file>
+#cu = #llvm.di_compile_unit<
+  id = distinct[0]<>, sourceLanguage = DW_LANG_C, file = #file,
+  producer = "MLIR", isOptimized = false, emissionKind = Full,
+  importedEntities = #ie
+>
+#sp_ty = #llvm.di_subroutine_type<callingConvention = DW_CC_normal>
+#sp = #llvm.di_subprogram<
+  compileUnit = #cu, scope = #file, name = "fn_cu_imports",
+  file = #file, line = 1, scopeLine = 1, subprogramFlags = Definition,
+  type = #sp_ty
+>
+
+// CHECK-LABEL: define void @fn_cu_imports()
+llvm.func @fn_cu_imports() {
+  llvm.return
+} loc(fused<#sp>["cu_imports.mlir":1:1])
+
+// CHECK-DAG: ![[FILE:[0-9]+]] = !DIFile(filename: "test.mlir", directory: "")
+// CHECK-DAG: ![[NS:[0-9]+]] = !DINamespace(name: "imported_ns"{{.*}})
+// CHECK-DAG: ![[IE:[0-9]+]] = !DIImportedEntity(tag: DW_TAG_imported_module{{.*}}entity: ![[NS]]{{.*}})
+// CHECK-DAG: ![[IMP_LIST:[0-9]+]] = !{![[IE]]}
+// CHECK-DAG: !DICompileUnit({{.*}}imports: ![[IMP_LIST]])

gysit

Thanks for extending the debug info!

I believe the bytecode tablegen needs to be updated as well?

gysit · 2026-03-26T06:49:21Z

Can you also update the byte code tablegen mlir/include/mlir/Dialect/LLVMIR/LLVMDialectBytecode.td to reflect this change, and add a byte code roundtrip test in mlir/test/Dialect/LLVMIR/debuginfo.mlir?

Thanks for pointing it out. Done.

gysit · 2026-03-26T06:53:37Z

Suggested change

if (node->getImportedEntities())

for (llvm::DIImportedEntity *ie : node->getImportedEntities())

if (DINodeAttr import = translate(static_cast<llvm::DINode *>(ie)))

imports.push_back(import);

ultra nit: I think the braces are not recommended here plus I would use a slightly longer variable name.

gysit · 2026-03-26T06:54:28Z

Suggested change

for (DINodeAttr importNode : attr.getImportedEntities())

importNodes.push_back(translate(importNode));

ultra nit: I prefer longer variable names.

gysit

Thanks for addressing the comments.

LGTM

Mostly mechanical changes to add the missing field. It can be help when importing something at non-local level like fortran modules or C++ namespaces.

1. Added field in LLVMDialectBytecode.td. Also added another missing field. 2. Updated test in debuginfo.mlir 3. Improve variable names

Mostly mechanical changes to add the missing field. It can help when importing something at non-local level like Fortran modules or C++ namespaces.

Dinistro · 2026-04-02T15:50:34Z

It seems that these importedEntities can form cyclic structures in LLVM IR. Feeding such an input to the importer causes a crash.

An example input is

source_filename = "reduced.ll"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

@__lookup_table_f64_log_coarse = external constant [512 x i128], !dbg !0

!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!17}

!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
!1 = distinct !DIGlobalVariable(name: "__lookup_table_f64_log_coarse", scope: !2, file: !12, line: 7, type: !13, isLocal: false, isDefinition: true)
!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !3, producer: "clang version 19.1.7", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, retainedTypes: !4, globals: !4, imports: !5, splitDebugInlining: false, nameTableKind: None)
!3 = !DIFile(filename: "f64_log.cpp", directory: "/build")
!4 = !{}
!5 = !{!6}
!6 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !2, entity: !7, file: !11, line: 10)
!7 = distinct !DICompositeType(tag: DW_TAG_class_type, name: "fma_u128_t", scope: !9, file: !8, line: 495, size: 128, flags: DIFlagTypePassByValue | DIFlagNonTrivial, elements: !4, identifier: "_ZTSN3foo5types10fma_u128_tE")
!8 = !DIFile(filename: "fma_definitions.hpp", directory: "/build")
!9 = !DINamespace(name: "types", scope: !10)
!10 = !DINamespace(name: "foo", scope: null)
!11 = !DIFile(filename: "arithmetic_helpers.hpp", directory: "/build")
!12 = !DIFile(filename: "f64_log_coarse.hpp", directory: "/build")
!13 = !DICompositeType(tag: DW_TAG_array_type, baseType: !14, size: 65536, elements: !4)
!14 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !15)
!15 = !DIDerivedType(tag: DW_TAG_typedef, name: "__uint128_t", file: !3, baseType: !16)
!16 = !DIBasicType(name: "unsigned __int128", size: 128, encoding: DW_ATE_unsigned)
!17 = !{i32 2, !"Debug Info Version", i32 3}

abidh · 2026-04-03T10:12:29Z

I think DICompileUnitAttr should also have DIRecursiveTypeAttrInterface to handle such cases. I have a patch that does that. Will open a PR.

Dinistro · 2026-04-07T11:47:16Z

@abidh What's the status of this? This is currently blocking down-stream integration for us.

abidh · 2026-04-07T13:41:54Z

Hi @Dinistro
Sorry it was easter holidays in the UK. I will try to get on it today. Although I wonder how it was working before. I guess because we just ignored the imports field in the DICompileUnit while translating.

Dinistro · 2026-04-07T13:56:04Z

Hi @Dinistro Sorry it was easter holidays in the UK. I will try to get on it today. Although I wonder how it was working before. I guess because we just ignored the imports field in the DICompileUnit while translating.

I guess the cycle was only introduced once the DIImportedEntity are being properly imported. Before that, the cycle was broken during the import.

abidh · 2026-04-07T15:49:57Z

#190808

abidh requested review from Dinistro, gysit and zyx-billy March 25, 2026 19:42

llvmbot added mlir:llvm mlir labels Mar 25, 2026

gysit reviewed Mar 26, 2026

View reviewed changes

gysit approved these changes Mar 26, 2026

View reviewed changes

abidh added 2 commits March 26, 2026 16:42

[mlir] Add importedEntities field in DIComplileUnitAttr.

dbc1ccb

Mostly mechanical changes to add the missing field. It can be help when importing something at non-local level like fortran modules or C++ namespaces.

Handle review comments.

fc7b578

1. Added field in LLVMDialectBytecode.td. Also added another missing field. 2. Updated test in debuginfo.mlir 3. Improve variable names

abidh force-pushed the cu_import branch from 1d6f241 to fc7b578 Compare March 26, 2026 16:48

abidh merged commit b912bad into llvm:main Mar 26, 2026
10 checks passed

abidh mentioned this pull request Mar 30, 2026

[flang][debug] Handle USE statements inside modules #186184

Merged


	for (DINodeAttr importNode : attr.getImportedEntities())
	importNodes.push_back(translate(importNode));

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llvmbot commented Mar 25, 2026 •

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