[Mlir-commits] [mlir] [MLIR:LLVM] Add UWTableKind attribute (PR #135811)

[Will Froom]

https://github.com/WillFroom updated https://github.com/llvm/llvm-project/pull/135811

>From 30bd5a3ed7a7cffab042d934b961bfd78f21c1d6 Mon Sep 17 00:00:00 2001
From: Will Froom <willfroom at google.com>
Date: Tue, 15 Apr 2025 16:11:11 +0000
Subject: [PATCH] [MLIR:LLVM] Add UWTableKind attribute

---
 .../mlir/Dialect/LLVMIR/LLVMAttrDefs.td       |  9 ++++++++
 mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td | 21 +++++++++++++++++++
 mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td   |  3 ++-
 mlir/lib/Target/LLVMIR/ModuleImport.cpp       |  7 +++++++
 mlir/lib/Target/LLVMIR/ModuleTranslation.cpp  |  3 +++
 mlir/test/Target/LLVMIR/Import/uwtable.ll     |  7 +++++++
 mlir/test/Target/LLVMIR/uwtable.mlir          |  8 +++++++
 7 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 mlir/test/Target/LLVMIR/Import/uwtable.ll
 create mode 100644 mlir/test/Target/LLVMIR/uwtable.mlir

diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
index 690243525ede4..0fa7e5eec2df5 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td
@@ -1365,4 +1365,13 @@ def LLVM_DependentLibrariesAttr
   let assemblyFormat = "`<` $libs `>`";
 }
 
+//===----------------------------------------------------------------------===//
+// UWTableKindAttr
+//===----------------------------------------------------------------------===//
+
+def UWTableKindAttr : LLVM_Attr<"UWTableKind", "uwtableKind"> {
+  let parameters = (ins "uwtable::UWTableKind":$uwtableKind);
+  let assemblyFormat = "`<` $uwtableKind `>`";
+}
+
 #endif // LLVMIR_ATTRDEFS
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td
index 34a30a00790ea..45ccf30644920 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td
@@ -855,4 +855,25 @@ def ModFlagBehaviorAttr : LLVM_EnumAttr<
   let cppNamespace = "::mlir::LLVM";
 }
 
+//===----------------------------------------------------------------------===//
+// UWTableKind
+//===----------------------------------------------------------------------===//
+
+def UWTableKindNone
+    : LLVM_EnumAttrCase<"None", "none", "None", 0>;
+def UWTableKindSync
+    : LLVM_EnumAttrCase<"Sync", "sync", "Sync", 1>;
+def UWTableKindAsync
+    : LLVM_EnumAttrCase<"Async", "async", "Async", 2>;
+
+// UWTableKind::Default is unsupported as the llvm enum value is the same as async  
+// which the generated enum converters can't deal with.
+def UWTableKindEnum : LLVM_EnumAttr<
+    "UWTableKind",
+    "::llvm::UWTableKind",
+    "LLVM Unwind Behavior",
+    [UWTableKindNone, UWTableKindSync, UWTableKindAsync]> {
+  let cppNamespace = "::mlir::LLVM::uwtable";
+}
+
 #endif // LLVMIR_ENUMS
diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
index e89e78aec7147..76a2ec47b3a22 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td
@@ -1842,7 +1842,8 @@ def LLVM_LLVMFuncOp : LLVM_Op<"func", [
     OptionalAttr<LLVM_VecTypeHintAttr>:$vec_type_hint,
     OptionalAttr<DenseI32ArrayAttr>:$work_group_size_hint,
     OptionalAttr<DenseI32ArrayAttr>:$reqd_work_group_size,
-    OptionalAttr<I32Attr>:$intel_reqd_sub_group_size
+    OptionalAttr<I32Attr>:$intel_reqd_sub_group_size,
+    OptionalAttr<UWTableKindAttr>:$uwtable_kind
   );
 
   let regions = (region AnyRegion:$body);
diff --git a/mlir/lib/Target/LLVMIR/ModuleImport.cpp b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
index 8e7a7ab95b6b6..481d719787397 100644
--- a/mlir/lib/Target/LLVMIR/ModuleImport.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleImport.cpp
@@ -2075,6 +2075,7 @@ static constexpr std::array kExplicitAttributes{
     StringLiteral("target-features"),
     StringLiteral("tune-cpu"),
     StringLiteral("unsafe-fp-math"),
+    StringLiteral("uwtable"),
     StringLiteral("vscale_range"),
     StringLiteral("willreturn"),
 };
@@ -2237,6 +2238,12 @@ void ModuleImport::processFunctionAttributes(llvm::Function *func,
   if (llvm::Attribute attr = func->getFnAttribute("fp-contract");
       attr.isStringAttribute())
     funcOp.setFpContractAttr(StringAttr::get(context, attr.getValueAsString()));
+
+  if (func->hasUWTable()) {
+    ::llvm::UWTableKind uwtableKind = func->getUWTableKind();
+    funcOp.setUwtableKindAttr(LLVM::UWTableKindAttr::get(
+        funcOp.getContext(), convertUWTableKindFromLLVM(uwtableKind)));
+  }
 }
 
 DictionaryAttr
diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
index ee7dc3a5231f4..d39ec0e801437 100644
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -1602,6 +1602,9 @@ static void convertFunctionAttributes(LLVMFuncOp func,
   if (FramePointerKindAttr fpAttr = func.getFramePointerAttr())
     llvmFunc->addFnAttr("frame-pointer", stringifyFramePointerKind(
                                              fpAttr.getFramePointerKind()));
+  if (UWTableKindAttr uwTableKindAttr = func.getUwtableKindAttr())
+    llvmFunc->setUWTableKind(
+        convertUWTableKindToLLVM(uwTableKindAttr.getUwtableKind()));
   convertFunctionMemoryAttributes(func, llvmFunc);
 }
 
diff --git a/mlir/test/Target/LLVMIR/Import/uwtable.ll b/mlir/test/Target/LLVMIR/Import/uwtable.ll
new file mode 100644
index 0000000000000..e5f5884240857
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/Import/uwtable.ll
@@ -0,0 +1,7 @@
+; RUN: mlir-translate -import-llvm -split-input-file %s | FileCheck %s
+
+; CHECK-LABEL: llvm.func @uwtable_func
+; CHECK-SAME: attributes {uwtable_kind = #llvm.uwtableKind<sync>}
+define void @uwtable_func() uwtable(sync) {
+  ret void
+}
diff --git a/mlir/test/Target/LLVMIR/uwtable.mlir b/mlir/test/Target/LLVMIR/uwtable.mlir
new file mode 100644
index 0000000000000..bd9a208ea75bb
--- /dev/null
+++ b/mlir/test/Target/LLVMIR/uwtable.mlir
@@ -0,0 +1,8 @@
+// RUN: mlir-translate -mlir-to-llvmir %s | FileCheck %s
+
+// CHECK-LABEL: define void @uwtable_func() 
+// CHECK-SAME: #[[ATTRS:[0-9]+]]
+llvm.func @uwtable_func() attributes {uwtable_kind = #llvm.uwtableKind<sync>}  {
+  llvm.return
+}
+// CHECK: attributes #[[ATTRS]] = { uwtable(sync) }