[mlir] Add support for the nest attribute to the LLVM-IR dialect conversion.

Differential Revision: https://reviews.llvm.org/D121948

Author: schweitzpgi

mlir/lib/Target/LLVMIR/ModuleTranslation.cpp

@@ -859,6 +859,15 @@ LogicalResult ModuleTranslation::convertOneFunction(LLVMFuncOp func) {
                            .addByValAttr(convertType(argTy.getElementType())));
     }
 
+    if (auto attr = func.getArgAttrOfType<UnitAttr>(argIdx, "llvm.nest")) {
+      auto argTy = mlirArg.getType();
+      if (!argTy.isa<LLVM::LLVMPointerType>())
+        return func.emitError(
+            "llvm.nest attribute attached to LLVM non-pointer argument");
+      llvmArg.addAttrs(llvm::AttrBuilder(llvmArg.getContext())
+                          .addAttribute(llvm::Attribute::Nest));
+    }
+
     mapValue(mlirArg, &llvmArg);
     argIdx++;
   }

mlir/test/Dialect/LLVMIR/func.mlir

@@ -97,6 +97,11 @@ module {
     llvm.return
   }
 
+  // CHECK: llvm.func @nestattr(%{{.*}}: !llvm.ptr<i32> {llvm.nest})
+  llvm.func @nestattr(%arg0: !llvm.ptr<i32> {llvm.nest}) {
+    llvm.return
+  }
+
   // CHECK: llvm.func @variadic(...)
   llvm.func @variadic(...)
 

mlir/test/Target/LLVMIR/llvmir-invalid.mlir

@@ -15,13 +15,20 @@ llvm.func @invalid_noalias(%arg0 : f32 {llvm.noalias}) -> f32 {
 // -----
 
 // expected-error @+1 {{llvm.sret attribute attached to LLVM non-pointer argument}}
-llvm.func @invalid_noalias(%arg0 : f32 {llvm.sret}) -> f32 {
+llvm.func @invalid_sret(%arg0 : f32 {llvm.sret}) -> f32 {
+  llvm.return %arg0 : f32
+}
+
+// -----
+
+// expected-error @+1 {{llvm.nest attribute attached to LLVM non-pointer argument}}
+llvm.func @invalid_nest(%arg0 : f32 {llvm.nest}) -> f32 {
   llvm.return %arg0 : f32
 }
 // -----
 
 // expected-error @+1 {{llvm.byval attribute attached to LLVM non-pointer argument}}
-llvm.func @invalid_noalias(%arg0 : f32 {llvm.byval}) -> f32 {
+llvm.func @invalid_byval(%arg0 : f32 {llvm.byval}) -> f32 {
   llvm.return %arg0 : f32
 }
 

mlir/test/Target/LLVMIR/llvmir.mlir

@@ -1057,6 +1057,11 @@ llvm.func @sretattr(%arg0: !llvm.ptr<i32> {llvm.sret}) {
   llvm.return
 }
 
+// CHECK-LABEL: define void @nestattr(i32* nest %
+llvm.func @nestattr(%arg0: !llvm.ptr<i32> {llvm.nest}) {
+  llvm.return
+}
+
 // CHECK-LABEL: define void @llvm_align(float* align 4 {{%*.}})
 llvm.func @llvm_align(%arg0: !llvm.ptr<f32> {llvm.align = 4}) {
   llvm.return