[Mlir-commits] [mlir] [mlir][debuginfo] Add support for subroutine annotations (PR #110946)

[Walter Erquinigo]

https://github.com/walter-erquinigo updated https://github.com/llvm/llvm-project/pull/110946

>From 54f5b32187bf61ad6dcd30955bf339a38638f531 Mon Sep 17 00:00:00 2001
From: walter erquinigo <walter at modular.com>
Date: Wed, 2 Oct 2024 22:32:09 -0400
Subject: [PATCH] [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.
---
 .../mlir/Dialect/LLVMIR/LLVMAttrDefs.td       | 22 ++++++++++++++++---
 mlir/lib/Dialect/LLVMIR/IR/LLVMAttrs.cpp      | 17 +++++++-------
 .../Transforms/DIScopeForLLVMFuncOp.cpp       |  2 +-
 mlir/lib/Target/LLVMIR/DebugTranslation.cpp   | 10 ++++++++-
 4 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
index 2da45eba77655b..dc711232aa9be8 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
@@ -586,7 +586,8 @@ 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
@@ -594,11 +595,11 @@ def LLVM_DISubprogramAttr : LLVM_Attr<"DISubprogram", "di_subprogram",
       "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
index bd2164e640e7b8..a4304ef6668e5e 100644
--- 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
index 2cfaffa7c8efce..59a4f8e9023582 100644
--- 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
index 8ca3beca6b66f7..709f1bb3dd0bcd 100644
--- 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;