[CIR][CIRGen][LowerToLLVM] Support for LinkerOptions

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/include/clang/CIR/MissingFeatures.h

@@ -370,7 +370,6 @@ struct MissingFeatures {
   static bool emitAtAvailableLinkGuard() { return false; }
   static bool emitLLVMUsed() { return false; }
   static bool sanStats() { return false; }
-  static bool linkerOptionsMetadata() { return false; }
   static bool emitModuleLinkOptions() { return false; }
   static bool elfDependentLibraries() { return false; }
   static bool dwarfVersion() { return false; }

clang/lib/CIR/CodeGen/CIRGenModule.cpp

@@ -2041,7 +2041,7 @@ void CIRGenModule::emitTopLevelDecl(Decl *decl) {
     case PCK_Unknown:
       llvm_unreachable("unexpected pragma comment kind");
     case PCK_Linker:
-      assert(!MissingFeatures::emitModuleLinkOptions() && "NYI");
+      appendLinkerOptions(PCD->getArg());
       break;
     case PCK_Lib:
       assert(!MissingFeatures::elfDependentLibraries() && "NYI");
@@ -3341,6 +3341,18 @@ CIRGenModule::GetAddrOfGlobal(GlobalDecl gd, ForDefinition_t isForDefinition) {
       .getDefiningOp();
 }
 
+void CIRGenModule::emitModuleLinkOptions() {
+  assert(!MissingFeatures::emitModuleLinkOptions());
+
+  // Add the linker options metadata flag.
+  llvm::SmallVector<mlir::Attribute, 16> args;
+  for (const auto &opt : linkerOptionsMetadata) {
+    args.push_back(opt);
+  }
+  mlir::ArrayAttr arr = builder.getArrayAttr(args);
+  getBuilder().create<cir::LinkerOptionsOp>(theModule->getLoc(), arr);
+}
+
 void CIRGenModule::Release() {
   assert(!MissingFeatures::emitModuleInitializers());
   emitDeferred(getCodeGenOpts().ClangIRBuildDeferredThreshold);
@@ -3392,9 +3404,9 @@ void CIRGenModule::Release() {
   assert(!MissingFeatures::emitLLVMUsed());
   assert(!MissingFeatures::sanStats());
 
-  if (codeGenOpts.Autolink && (astContext.getLangOpts().Modules ||
-                               !MissingFeatures::linkerOptionsMetadata())) {
-    assert(!MissingFeatures::emitModuleLinkOptions());
+  if (codeGenOpts.Autolink &&
+      (astContext.getLangOpts().Modules || !linkerOptionsMetadata.empty())) {
+    emitModuleLinkOptions();
   }
 
   // On ELF we pass the dependent library specifiers directly to the linker
@@ -4229,6 +4241,11 @@ void CIRGenModule::emitGlobalAnnotations() {
   deferredAnnotations.clear();
 }
 
+void CIRGenModule::appendLinkerOptions(StringRef Opts) {
+  linkerOptionsMetadata.push_back(
+      mlir::StringAttr::get(&getMLIRContext(), Opts));
+}
+
 cir::TBAAAttr CIRGenModule::getTBAATypeInfo(QualType qTy) {
   if (!tbaa) {
     return nullptr;

clang/lib/CIR/CodeGen/CIRGenModule.h

@@ -154,6 +154,8 @@ class CIRGenModule : public CIRGenTypeCache {
   llvm::DenseMap<const Expr *, mlir::Operation *>
       materializedGlobalTemporaryMap;
 
+  llvm::SmallVector<mlir::StringAttr, 16> linkerOptionsMetadata;
+
 public:
   mlir::ModuleOp getModule() const { return theModule; }
   CIRGenBuilderTy &getBuilder() { return builder; }
@@ -776,6 +778,9 @@ class CIRGenModule : public CIRGenTypeCache {
   /// Helper for `emitDeferred` to apply actual codegen.
   void emitGlobalDecl(clang::GlobalDecl &D);
 
+  /// Emit the link options introduced by imported modules.
+  void emitModuleLinkOptions();
+
   const llvm::Triple &getTriple() const { return target.getTriple(); }
 
   // Finalize CIR code generation.
@@ -952,6 +957,9 @@ class CIRGenModule : public CIRGenTypeCache {
   /// Add global annotations for a global value.
   /// Those annotations are emitted during lowering to the LLVM code.
   void addGlobalAnnotations(const ValueDecl *d, mlir::Operation *gv);
+
+  /// Appends Opts to the "llvm.linker.options" metadata value.
+  void appendLinkerOptions(StringRef Opts);
 };
 } // namespace clang::CIRGen
 

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

@@ -4017,6 +4017,18 @@ 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

@@ -4230,6 +4230,15 @@ 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(
       CIRToLLVMIsConstantOpLowering,
       CIRToLLVMIsFPClassOpLowering,
       CIRToLLVMLLVMIntrinsicCallOpLowering,
+      CIRToLLVMLinkerOptionsOpLowering,
       CIRToLLVMMemChrOpLowering,
       CIRToLLVMMemCpyInlineOpLowering,
       CIRToLLVMMemCpyOpLowering,

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: }