[CIR][LowerToLLVM] Support for LinkerOptions lowering (llvm#1532)

- Part of llvm#70.

Author: el-ev

clang/include/clang/CIR/Dialect/IR/CIROps.td

@@ -5691,6 +5691,36 @@ def SignBitOp : CIR_Op<"signbit", [Pure]> {
   }];
 }
 
+//===----------------------------------------------------------------------===//
+// LinkerOptionsOp
+//===----------------------------------------------------------------------===//
+
+def LinkerOptionsOp : CIR_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.
+    cir.linker_options ["/DEFAULTLIB:", "libcmt"]
+
+    // Link against aarch64 compiler-rt builtins
+    cir.linker_options ["-l", "clang_rt.builtins-aarch64"]
+  }];
+
+  let arguments = (ins StrArrayAttr:$options);
+
+  let assemblyFormat = [{
+    $options attr-dict
+  }];
+
+  let hasVerifier = 1;
+}
+
 //===----------------------------------------------------------------------===//
 // Standard library function calls
 //===----------------------------------------------------------------------===//

clang/lib/CIR/Dialect/IR/CIRDialect.cpp

@@ -4038,6 +4038,18 @@ LogicalResult cir::CatchParamOp::verify() {
   return success();
 }
 
+//===----------------------------------------------------------------------===//
+// LinkerOptionsOp
+//===----------------------------------------------------------------------===//
+
+LogicalResult cir::LinkerOptionsOp::verify() {
+  if (mlir::Operation *parentOp = (*this)->getParentOp();
+      parentOp && !isa<mlir::ModuleOp>(parentOp))
+    return emitOpError("must appear at the module level");
+
+  return success();
+}
+
 //===----------------------------------------------------------------------===//
 // TableGen'd op method definitions
 //===----------------------------------------------------------------------===//

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -4231,6 +4231,15 @@ mlir::LogicalResult CIRToLLVMSignBitOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+mlir::LogicalResult CIRToLLVMLinkerOptionsOpLowering::matchAndRewrite(
+    cir::LinkerOptionsOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  auto newOp = rewriter.create<mlir::LLVM::LinkerOptionsOp>(
+      op.getLoc(), op.getOptionsAttr());
+  rewriter.replaceOp(op, newOp);
+  return mlir::success();
+}
+
 void populateCIRToLLVMConversionPatterns(
     mlir::RewritePatternSet &patterns, mlir::TypeConverter &converter,
     mlir::DataLayout &dataLayout, cir::LowerModule *lowerModule,
@@ -4315,6 +4324,7 @@ void populateCIRToLLVMConversionPatterns(
       CIRToLLVMInsertMemberOpLowering,
       CIRToLLVMIsConstantOpLowering,
       CIRToLLVMIsFPClassOpLowering,
+      CIRToLLVMLinkerOptionsOpLowering,
       CIRToLLVMLLVMIntrinsicCallOpLowering,
       CIRToLLVMMemChrOpLowering,
       CIRToLLVMMemCpyInlineOpLowering,

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h

@@ -1246,6 +1246,17 @@ class CIRToLLVMSignBitOpLowering
   matchAndRewrite(cir::SignBitOp op, OpAdaptor adaptor,
                   mlir::ConversionPatternRewriter &rewriter) const override;
 };
+
+class CIRToLLVMLinkerOptionsOpLowering
+    : public mlir::OpConversionPattern<cir::LinkerOptionsOp> {
+public:
+  using OpConversionPattern<cir::LinkerOptionsOp>::OpConversionPattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(cir::LinkerOptionsOp op, OpAdaptor adaptor,
+                  mlir::ConversionPatternRewriter &rewriter) const override;
+};
+
 mlir::ArrayAttr lowerCIRTBAAAttr(mlir::Attribute tbaa,
                                  mlir::ConversionPatternRewriter &rewriter,
                                  cir::LowerModule *lowerMod);

clang/test/CIR/Lowering/linker-options.cir

@@ -0,0 +1,9 @@
+// RUN: cir-opt -cir-to-llvm %s | FileCheck %s
+
+module {
+  cir.linker_options ["/DEFAULTLIB:", "libcmt"]
+} 
+
+// CHECK: module {
+// CHECK-NEXT:   llvm.linker_options ["/DEFAULTLIB:", "libcmt"]
+// CHECK-NEXT: }