[mlir][debuginfo] Add support for subroutine annotations

LLVM already supports `DW_TAG_LLVM_annotation` entries for subroutines, but this hasn't been surfaced to the LLVM dialect. I'm doing the minimal amount of work to support string-based annotations, which is useful for attaching metadata to functions, which is useful for debuggers to offer features beyond basic DWARF. As LLVM already supports this, this patch is not controversial.
llvm · Oct 3, 2024 · 9c3c671 · 9c3c671
1 parent e7a43ca
commit 9c3c671
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Showing 4 changed files with 51 additions and 15 deletions.
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
@@ -586,19 +586,20 @@ def LLVM_DISubprogramAttr : LLVM_Attr<"DISubprogram", "di_subprogram",
     OptionalParameter<"unsigned">:$scopeLine,
     OptionalParameter<"DISubprogramFlags">:$subprogramFlags,
     OptionalParameter<"DISubroutineTypeAttr">:$type,
-    OptionalArrayRefParameter<"DINodeAttr">:$retainedNodes
+    OptionalArrayRefParameter<"DINodeAttr">:$retainedNodes,
+    OptionalArrayRefParameter<"DINodeAttr">:$annotations
   );
   let builders = [
     AttrBuilder<(ins
       "DistinctAttr":$id, "DICompileUnitAttr":$compileUnit,
       "DIScopeAttr":$scope, "StringAttr":$name, "StringAttr":$linkageName,
       "DIFileAttr":$file, "unsigned":$line, "unsigned":$scopeLine,
       "DISubprogramFlags":$subprogramFlags, "DISubroutineTypeAttr":$type,
-      "ArrayRef<DINodeAttr>":$retainedNodes
+      "ArrayRef<DINodeAttr>":$retainedNodes, "ArrayRef<DINodeAttr>":$annotations
     ), [{
       return $_get($_ctxt, /*recId=*/nullptr, /*isRecSelf=*/false, id, compileUnit,
                    scope, name, linkageName, file, line, scopeLine,
-                   subprogramFlags, type, retainedNodes);
+                   subprogramFlags, type, retainedNodes, annotations);
     }]>
   ];
   let assemblyFormat = "`<` struct(params) `>`";
@@ -670,6 +671,21 @@ def LLVM_DIImportedEntityAttr : LLVM_Attr<"DIImportedEntity", "di_imported_entit
   let assemblyFormat = "`<` struct(params) `>`";
 }
 
+//===----------------------------------------------------------------------===//
+// DIStringAnnotationAttr
+//===----------------------------------------------------------------------===//
+
+def LLVM_DIStringAnnotationAttr : LLVM_Attr<"DIStringAnnotation",
+                                            "di_string_annotation",
+                                           /*traits=*/[], "DINodeAttr"> {
+  let parameters = (ins
+    "StringAttr":$name,
+    "StringAttr":$value
+  );
+
+  let assemblyFormat = "`<` struct(params) `>`";
+}
+
 //===----------------------------------------------------------------------===//
 // DISubrangeAttr
 //===----------------------------------------------------------------------===//

diff --git a/mlir/lib/Dialect/LLVMIR/IR/LLVMAttrs.cpp b/mlir/lib/Dialect/LLVMIR/IR/LLVMAttrs.cpp
@@ -60,9 +60,9 @@ bool DINodeAttr::classof(Attribute attr) {
                    DIDerivedTypeAttr, DIFileAttr, DIGlobalVariableAttr,
                    DIImportedEntityAttr, DILabelAttr, DILexicalBlockAttr,
                    DILexicalBlockFileAttr, DILocalVariableAttr, DIModuleAttr,
-                   DINamespaceAttr, DINullTypeAttr, DIStringTypeAttr,
-                   DISubprogramAttr, DISubrangeAttr, DISubroutineTypeAttr>(
-      attr);
+                   DINamespaceAttr, DINullTypeAttr, DIStringAnnotationAttr,
+                   DIStringTypeAttr, DISubprogramAttr, DISubrangeAttr,
+                   DISubroutineTypeAttr>(attr);
 }
 
 //===----------------------------------------------------------------------===//
@@ -221,15 +221,16 @@ DICompositeTypeAttr::getRecSelf(DistinctAttr recId) {
 //===----------------------------------------------------------------------===//
 
 DIRecursiveTypeAttrInterface DISubprogramAttr::withRecId(DistinctAttr recId) {
-  return DISubprogramAttr::get(
-      getContext(), recId, getIsRecSelf(), getId(), getCompileUnit(),
-      getScope(), getName(), getLinkageName(), getFile(), getLine(),
-      getScopeLine(), getSubprogramFlags(), getType(), getRetainedNodes());
+  return DISubprogramAttr::get(getContext(), recId, getIsRecSelf(), getId(),
+                               getCompileUnit(), getScope(), getName(),
+                               getLinkageName(), getFile(), getLine(),
+                               getScopeLine(), getSubprogramFlags(), getType(),
+                               getRetainedNodes(), getAnnotations());
 }
 
 DIRecursiveTypeAttrInterface DISubprogramAttr::getRecSelf(DistinctAttr recId) {
   return DISubprogramAttr::get(recId.getContext(), recId, /*isRecSelf=*/true,
-                               {}, {}, {}, {}, {}, 0, 0, {}, {}, {}, {});
+                               {}, {}, {}, {}, {}, 0, 0, {}, {}, {}, {}, {});
 }
 
 //===----------------------------------------------------------------------===//

diff --git a/mlir/lib/Dialect/LLVMIR/Transforms/DIScopeForLLVMFuncOp.cpp b/mlir/lib/Dialect/LLVMIR/Transforms/DIScopeForLLVMFuncOp.cpp
@@ -78,7 +78,7 @@ static void addScopeToFunction(LLVM::LLVMFuncOp llvmFunc,
   auto subprogramAttr = LLVM::DISubprogramAttr::get(
       context, id, compileUnitAttr, fileAttr, funcName, funcName, fileAttr,
       /*line=*/line, /*scopeline=*/col, subprogramFlags, subroutineTypeAttr,
-      /*retainedNodes=*/{});
+      /*retainedNodes=*/{}, /*annotations=*/{});
   llvmFunc->setLoc(FusedLoc::get(context, {loc}, subprogramAttr));
 }
 

diff --git a/mlir/lib/Target/LLVMIR/DebugTranslation.cpp b/mlir/lib/Target/LLVMIR/DebugTranslation.cpp
@@ -102,6 +102,13 @@ DebugTranslation::getMDTupleOrNull(ArrayRef<DINodeAttr> elements) {
     return nullptr;
   SmallVector<llvm::Metadata *> llvmElements = llvm::to_vector(
       llvm::map_range(elements, [&](DINodeAttr attr) -> llvm::Metadata * {
+        if (DIStringAnnotationAttr annAttr =
+                dyn_cast<DIStringAnnotationAttr>(attr)) {
+          llvm::Metadata *ops[2] = {
+              llvm::MDString::get(llvmCtx, annAttr.getName()),
+              llvm::MDString::get(llvmCtx, annAttr.getValue())};
+          return llvm::MDNode::get(llvmCtx, ops);
+        }
         return translate(attr);
       }));
   return llvm::MDNode::get(llvmCtx, llvmElements);
@@ -332,7 +339,8 @@ llvm::DISubprogram *DebugTranslation::translateImpl(DISubprogramAttr attr) {
       /*ThisAdjustment=*/0, llvm::DINode::FlagZero,
       static_cast<llvm::DISubprogram::DISPFlags>(attr.getSubprogramFlags()),
       compileUnit, /*TemplateParams=*/nullptr, /*Declaration=*/nullptr,
-      getMDTupleOrNull(attr.getRetainedNodes()));
+      getMDTupleOrNull(attr.getRetainedNodes()), nullptr,
+      getMDTupleOrNull(attr.getAnnotations()));
   if (attr.getId())
     distinctAttrToNode.try_emplace(attr.getId(), node);
   return node;
@@ -361,6 +369,16 @@ DebugTranslation::translateImpl(DIImportedEntityAttr attr) {
       getMDStringOrNull(attr.getName()), getMDTupleOrNull(attr.getElements()));
 }
 
+/*
+llvm::DINodeArray *
+DebugTranslation::translateImpl(DIStringAnnotationAttr attr) {
+  llvm::DINodeArray arr;
+  arr->push_back(llvm::MDString::get(llvmCtx, attr.getName()));
+  arr->push_back(llvm::MDString::get(llvmCtx, attr.getValue()));
+  return arr;
+}
+*/
+
 llvm::DISubrange *DebugTranslation::translateImpl(DISubrangeAttr attr) {
   auto getMetadataOrNull = [&](Attribute attr) -> llvm::Metadata * {
     if (!attr)
@@ -426,8 +444,9 @@ llvm::DINode *DebugTranslation::translate(DINodeAttr attr) {
                      DIImportedEntityAttr, DILabelAttr, DILexicalBlockAttr,
                      DILexicalBlockFileAttr, DILocalVariableAttr, DIModuleAttr,
                      DINamespaceAttr, DINullTypeAttr, DIStringTypeAttr,
-                     DISubprogramAttr, DISubrangeAttr, DISubroutineTypeAttr>(
-                   [&](auto attr) { return translateImpl(attr); });
+                     DISubprogramAttr, DISubrangeAttr, DISubroutineTypeAttr
+                     // DIStringAnnotationAttr
+                     >([&](auto attr) { return translateImpl(attr); });
 
   if (node && !node->isTemporary())
     attrToNode.insert({attr, node});