[mlir] Add llvm.linker.options operation to the LLVM IR Dialect

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

@@ -1825,4 +1825,33 @@ def LLVM_CallIntrinsicOp
   let hasVerifier = 1;
 }
 
+def LLVM_LinkerOptionsOp
+    : LLVM_Op<"linker_options"> {
+  let summary = "Options to pass to the linker when the object file is linked";
+  let description = [{
+    Pass the given options to the linker when the resulting object file is linked.
+    This is used extensively on Windows to determine the C runtime that the object
+    files should link against.
+
+    Examples:
+    ```mlir
+    // Link against the MSVC static threaded CRT.
+    llvm.linker_options ["/DEFAULTLIB:", "libcmt"]
+
+    // Link against aarch64 compiler-rt builtins
+    llvm.linker_options ["-l", "clang_rt.builtins-aarch64"]
+    ```
+  }];
+  let arguments  = (ins StrArrayAttr:$options);
+  let assemblyFormat = [{
+    $options attr-dict
+  }];
+
+  let llvmBuilder = [{
+    convertLinkerOptionsOp($options, builder, moduleTranslation);
+  }];
+
+  let hasVerifier = 1;
+}
+
 #endif // LLVMIR_OPS

mlir/include/mlir/Target/LLVMIR/ModuleImport.h

@@ -177,6 +177,10 @@ class ModuleImport {
   /// implement the fastmath interface.
   void setFastmathFlagsAttr(llvm::Instruction *inst, Operation *op) const;
 
+  /// Converts !llvm.linker.options metadata to the llvm.linker.options
+  /// LLVM dialect operation.
+  LogicalResult convertLinkerOptionsMetadata();
+
   /// Converts all LLVM metadata nodes that translate to attributes such as
   /// alias analysis or access group metadata, and builds a map from the
   /// metadata nodes to the converted attributes.

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

@@ -3072,6 +3072,17 @@ struct LLVMOpAsmDialectInterface : public OpAsmDialectInterface {
 };
 } // namespace
 
+//===----------------------------------------------------------------------===//
+// LinkerOptionsOp
+//===----------------------------------------------------------------------===//
+
+LogicalResult LinkerOptionsOp::verify() {
+  if (mlir::Operation *parentOp = (*this)->getParentOp();
+      parentOp && !satisfiesLLVMModule(parentOp))
+    return emitOpError("must appear at the module level");
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // LLVMDialect initialization, type parsing, and registration.
 //===----------------------------------------------------------------------===//

mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp

@@ -172,6 +172,24 @@ convertCallLLVMIntrinsicOp(CallIntrinsicOp op, llvm::IRBuilderBase &builder,
   return success();
 }
 
+static void convertLinkerOptionsOp(ArrayAttr options,
+                                   llvm::IRBuilderBase &builder,
+                                   LLVM::ModuleTranslation &moduleTranslation) {
+  llvm::Module *llvmModule = moduleTranslation.getLLVMModule();
+  llvm::LLVMContext &context = llvmModule->getContext();
+  llvm::NamedMDNode *linkerMDNode =
+      llvmModule->getOrInsertNamedMetadata("llvm.linker.options");
+  SmallVector<llvm::Metadata *> MDNodes;
+  MDNodes.reserve(options.size());
+  for (auto s : options.getAsRange<StringAttr>()) {
+    auto *MDNode = llvm::MDString::get(context, s.getValue());
+    MDNodes.push_back(MDNode);
+  }
+
+  auto *listMDNode = llvm::MDTuple::get(context, MDNodes);
+  linkerMDNode->addOperand(listMDNode);
+}
+
 static LogicalResult
 convertOperationImpl(Operation &opInst, llvm::IRBuilderBase &builder,
                      LLVM::ModuleTranslation &moduleTranslation) {

mlir/lib/Target/LLVMIR/ModuleImport.cpp

@@ -487,6 +487,23 @@ void ModuleImport::addDebugIntrinsic(llvm::CallInst *intrinsic) {
   debugIntrinsics.insert(intrinsic);
 }
 
+LogicalResult ModuleImport::convertLinkerOptionsMetadata() {
+  for (const llvm::NamedMDNode &named : llvmModule->named_metadata()) {
+    if (named.getName() != "llvm.linker.options")
+      continue;
+    // llvm.linker.options operands are lists of strings.
+    for (const llvm::MDNode *md : named.operands()) {
+      SmallVector<StringRef> options;
+      options.reserve(md->getNumOperands());
+      for (const llvm::MDOperand &option : md->operands())
+        options.push_back(cast<llvm::MDString>(option)->getString());
+      builder.create<LLVM::LinkerOptionsOp>(mlirModule.getLoc(),
+                                            builder.getStrArrayAttr(options));
+    }
+  }
+  return success();
+}
+
 LogicalResult ModuleImport::convertMetadata() {
   OpBuilder::InsertionGuard guard(builder);
   builder.setInsertionPointToEnd(mlirModule.getBody());
@@ -513,6 +530,8 @@ LogicalResult ModuleImport::convertMetadata() {
           return failure();
     }
   }
+  if (failed(convertLinkerOptionsMetadata()))
+    return failure();
   return success();
 }
 

mlir/test/Target/LLVMIR/Import/metadata-linker-options.ll

@@ -0,0 +1,15 @@
+; RUN: mlir-translate -import-llvm -split-input-file %s | FileCheck %s
+
+; CHECK: llvm.linker_options ["DEFAULTLIB:", "libcmt"]
+!llvm.linker.options = !{!0}
+!0 = !{!"DEFAULTLIB:", !"libcmt"}
+
+; // -----
+
+!llvm.linker.options = !{!0, !1, !2}
+; CHECK: llvm.linker_options ["DEFAULTLIB:", "libcmt"]
+!0 = !{!"DEFAULTLIB:", !"libcmt"}
+; CHECK: llvm.linker_options ["DEFAULTLIB:", "libcmtd"]
+!1 = !{!"DEFAULTLIB:", !"libcmtd"}
+; CHECK: llvm.linker_options ["-lm"]
+!2 = !{!"-lm"}

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

@@ -253,3 +253,10 @@ llvm.comdat @__llvm_comdat_1 {
   // expected-error @below{{comdat selection symbols must be unique even in different comdat regions}}
   llvm.comdat_selector @foo any
 }
+
+// -----
+
+llvm.func @foo() {
+  // expected-error @below{{must appear at the module level}}
+  llvm.linker_options ["test"]
+}

mlir/test/Target/LLVMIR/llvmir.mlir

@@ -2337,3 +2337,9 @@ llvm.func @zeroinit_complex_local_aggregate() {
 
   llvm.return
 }
+
+//CHECK: !llvm.linker.options = !{![[MD0:[0-9]+]], ![[MD1:[0-9]+]]}
+//CHECK: ![[MD0]] = !{!"/DEFAULTLIB:", !"libcmt"}
+llvm.linker_options ["/DEFAULTLIB:", "libcmt"]
+//CHECK: ![[MD1]] = !{!"/DEFAULTLIB:", !"libcmtd"}
+llvm.linker_options ["/DEFAULTLIB:", "libcmtd"]