[llvm-branch-commits] [mlir] [MLIR][LLVM] Translate LLVMFuncOp function metadata (PR #203021)

Akimasa Watanuki via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Fri Jun 12 09:06:37 PDT 2026


https://github.com/Men-cotton updated https://github.com/llvm/llvm-project/pull/203021

>From 98c27df0b5038a358b7a9f72d130d7113b8b92a8 Mon Sep 17 00:00:00 2001
From: mencotton <mencotton0410 at gmail.com>
Date: Mon, 8 Jun 2026 20:52:56 +0900
Subject: [PATCH] [MLIR][LLVM] Translate LLVMFuncOp function metadata

Materialize LLVMFuncOp function_metadata through ModuleTranslation metadata conversion. Attach function metadata after module-level symbols are mapped so metadata references to functions, globals, aliases, and ifuncs can be resolved.
---
 mlir/lib/Target/LLVMIR/ModuleTranslation.cpp  |  53 +++++-
 .../test/Target/LLVMIR/function-metadata.mlir | 156 ++++++++++++++++++
 2 files changed, 204 insertions(+), 5 deletions(-)
 create mode 100644 mlir/test/Target/LLVMIR/function-metadata.mlir

diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
index 2193b415637a3..c56104dbb8d4b 100644
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -1617,6 +1617,45 @@ FailureOr<llvm::Metadata *> ModuleTranslation::convertMetadataAttr(
       });
 }
 
+/// Converts generic function metadata from `func` and attaches it to
+/// `llvmFunc`.
+static LogicalResult convertFunctionMetadata(ModuleTranslation &translation,
+                                             LLVMFuncOp func,
+                                             llvm::Function *llvmFunc) {
+  ArrayAttr metadata = func.getFunctionMetadataAttr();
+  if (!metadata)
+    return success();
+
+  for (auto entry : metadata.getAsRange<LLVM::FunctionMetadataAttr>()) {
+    StringRef metadataName = entry.getMetadataName().getValue();
+
+    FailureOr<llvm::Metadata *> md =
+        translation.convertMetadataAttr(entry.getNode(), [&]() {
+          return func.emitError()
+                 << "failed to convert function_metadata entry '"
+                 << metadataName << "': ";
+        });
+    if (failed(md))
+      return failure();
+    llvm::MDNode *node = llvm::dyn_cast_if_present<llvm::MDNode>(*md);
+    if (!node)
+      return func.emitError() << "failed to convert function_metadata entry '"
+                              << metadataName << "'";
+    llvmFunc->addMetadata(metadataName, *node);
+  }
+  return success();
+}
+
+static LogicalResult convertFunctionMetadata(ModuleTranslation &translation,
+                                             Operation *module) {
+  for (auto function : getModuleBody(module).getOps<LLVMFuncOp>()) {
+    llvm::Function *llvmFunc = translation.lookupFunction(function.getName());
+    if (failed(convertFunctionMetadata(translation, function, llvmFunc)))
+      return failure();
+  }
+  return success();
+}
+
 LogicalResult ModuleTranslation::convertOneFunction(LLVMFuncOp func) {
   // Clear the block, branch value mappings, they are only relevant within one
   // function.
@@ -2036,18 +2075,20 @@ ModuleTranslation::convertParameterAttrs(Location loc,
 
 LogicalResult ModuleTranslation::convertFunctionSignatures() {
   // Declare all functions first because there may be function calls that form a
-  // call graph with cycles, or global initializers that reference functions.
+  // call graph with cycles, global initializers that reference functions, or
+  // metadata that references functions declared later in the module.
   for (auto function : getModuleBody(mlirModule).getOps<LLVMFuncOp>()) {
     llvm::FunctionCallee llvmFuncCst = llvmModule->getOrInsertFunction(
         function.getName(),
         cast<llvm::FunctionType>(convertType(function.getFunctionType())));
     llvm::Function *llvmFunc = cast<llvm::Function>(llvmFuncCst.getCallee());
+    mapFunction(function.getName(), llvmFunc);
+  }
+
+  for (auto function : getModuleBody(mlirModule).getOps<LLVMFuncOp>()) {
+    llvm::Function *llvmFunc = lookupFunction(function.getName());
     llvmFunc->setLinkage(convertLinkageToLLVM(function.getLinkage()));
     llvmFunc->setCallingConv(convertCConvToLLVM(function.getCConv()));
-    mapFunction(function.getName(), llvmFunc);
-    if (function.getFunctionMetadataAttr())
-      return function.emitError()
-             << "not yet implemented: translating function_metadata to LLVM IR";
     addRuntimePreemptionSpecifier(function.getDsoLocal(), llvmFunc);
 
     // Convert function attributes.
@@ -2620,6 +2661,8 @@ mlir::translateModuleToLLVMIR(Operation *module, llvm::LLVMContext &llvmContext,
     return nullptr;
   if (failed(translator.convertIFuncs()))
     return nullptr;
+  if (failed(convertFunctionMetadata(translator, module)))
+    return nullptr;
   if (failed(translator.createTBAAMetadata()))
     return nullptr;
   if (failed(translator.createIdentMetadata()))
diff --git a/mlir/test/Target/LLVMIR/function-metadata.mlir b/mlir/test/Target/LLVMIR/function-metadata.mlir
new file mode 100644
index 0000000000000..8816369b3d02a
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/function-metadata.mlir
@@ -0,0 +1,156 @@
+// RUN: mlir-translate -verify-diagnostics -split-input-file -mlir-to-llvmir %s | FileCheck %s
+
+// CHECK-LABEL: define void @function_metadata()
+// CHECK-SAME: !type ![[TYPE:[0-9]+]]
+// CHECK-SAME: !annotation ![[ANNOTATION:[0-9]+]]
+llvm.func @function_metadata() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"annotation", #llvm.md_node<
+      #llvm.md_string<"function annotation">
+    >>,
+    #llvm.func_metadata<"type", #llvm.md_node<
+      #llvm.md_const<0 : i64>,
+      #llvm.md_string<"typeid">
+    >>
+  ]
+} {
+  llvm.return
+}
+
+// CHECK-DAG: ![[ANNOTATION]] = !{!"function annotation"}
+// CHECK-DAG: ![[TYPE]] = !{i64 0, !"typeid"}
+
+// -----
+
+// CHECK-LABEL: declare !annotation
+// CHECK-SAME: ![[DECL_ANNOTATION:[0-9]+]] void @declaration_metadata()
+llvm.func @declaration_metadata() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"annotation", #llvm.md_node<
+      #llvm.md_string<"declaration annotation">
+    >>
+  ]
+}
+
+// CHECK-DAG: ![[DECL_ANNOTATION]] = !{!"declaration annotation"}
+
+// -----
+
+// CHECK-LABEL: define void @uses_later()
+// CHECK-SAME: !callee ![[LATER_NODE:[0-9]+]]
+llvm.func @uses_later() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"callee", #llvm.md_node<#llvm.md_string<"later">, #llvm.md_value<@later>>>
+  ]
+} {
+  llvm.return
+}
+
+llvm.func @later() {
+  llvm.return
+}
+
+// CHECK-DAG: ![[LATER_NODE]] = !{!"later", ptr @later}
+
+// -----
+
+llvm.mlir.global internal @metadata_global(0 : i32) : i32
+
+// CHECK-LABEL: define void @uses_global()
+// CHECK-SAME: !callee ![[GLOBAL_NODE:[0-9]+]]
+llvm.func @uses_global() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"callee", #llvm.md_node<#llvm.md_value<@metadata_global>>>
+  ]
+} {
+  llvm.return
+}
+
+// CHECK-DAG: ![[GLOBAL_NODE]] = !{ptr @metadata_global}
+
+// -----
+
+llvm.func @metadata_alias_target() {
+  llvm.return
+}
+
+llvm.mlir.alias external @metadata_alias : !llvm.func<void ()> {
+  %0 = llvm.mlir.addressof @metadata_alias_target : !llvm.ptr
+  llvm.return %0 : !llvm.ptr
+}
+
+// CHECK-LABEL: define void @uses_alias()
+// CHECK-SAME: !callee ![[ALIAS_NODE:[0-9]+]]
+llvm.func @uses_alias() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"callee", #llvm.md_node<#llvm.md_value<@metadata_alias>>>
+  ]
+} {
+  llvm.return
+}
+
+// CHECK-DAG: ![[ALIAS_NODE]] = !{ptr @metadata_alias}
+
+// -----
+
+llvm.mlir.ifunc external @metadata_ifunc : !llvm.func<void ()>, !llvm.ptr @metadata_ifunc_resolver
+
+llvm.func @metadata_ifunc_resolver() -> !llvm.ptr {
+  %0 = llvm.mlir.addressof @metadata_ifunc_target : !llvm.ptr
+  llvm.return %0 : !llvm.ptr
+}
+
+llvm.func @metadata_ifunc_target() {
+  llvm.return
+}
+
+// CHECK-LABEL: define void @uses_ifunc()
+// CHECK-SAME: !callee ![[IFUNC_NODE:[0-9]+]]
+llvm.func @uses_ifunc() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"callee", #llvm.md_node<#llvm.md_value<@metadata_ifunc>>>
+  ]
+} {
+  llvm.return
+}
+
+// CHECK-DAG: ![[IFUNC_NODE]] = !{ptr @metadata_ifunc}
+
+// -----
+
+// CHECK-LABEL: define void @repeated_kind_metadata()
+// CHECK-SAME: !type ![[TYPE0:[0-9]+]]
+// CHECK-SAME: !type ![[TYPE1:[0-9]+]]
+llvm.func @repeated_kind_metadata() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"type", #llvm.md_node<#llvm.md_const<0 : i64>, #llvm.md_string<"typeid0">>>,
+    #llvm.func_metadata<"type", #llvm.md_node<#llvm.md_const<0 : i64>, #llvm.md_string<"typeid1">>>
+  ]
+} {
+  llvm.return
+}
+
+// CHECK-DAG: ![[TYPE0]] = !{i64 0, !"typeid0"}
+// CHECK-DAG: ![[TYPE1]] = !{i64 0, !"typeid1"}
+
+// -----
+
+// expected-error @below{{failed to convert function_metadata entry 'callee': could not resolve metadata reference '@missing'}}
+llvm.func @missing_function_metadata_ref() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"callee", #llvm.md_node<#llvm.md_value<@missing>>>
+  ]
+} {
+  llvm.return
+}
+
+// -----
+
+// expected-error @below{{failed to convert function_metadata entry 'bad': expected integer attribute in metadata constant}}
+llvm.func @malformed_function_metadata() attributes {
+  function_metadata = [
+    #llvm.func_metadata<"bad", #llvm.md_node<#llvm.md_const<"not an integer">>>
+  ]
+} {
+  llvm.return
+}



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