AddrSpaceLowering in TypeConverter

addrspace-lowering.patch

diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index d9b4724e4c71..c3664fca1a4f 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -68,6 +68,9 @@
 #include <optional>
 #include <set>
 
+// FIXME: Use a public header in include/ when there's one available
+#include "../../Dialect/Transforms/TargetLowering/LowerModule.h"
+
 using namespace cir;
 using namespace llvm;
 
@@ -3462,24 +3465,27 @@ void populateCIRToLLVMConversionPatterns(mlir::RewritePatternSet &patterns,
 }
 
 namespace {
-void prepareTypeConverter(mlir::LLVMTypeConverter &converter,
-                          mlir::DataLayout &dataLayout) {
-  converter.addConversion([&](mlir::cir::PointerType type) -> mlir::Type {
+void prepareTypeConverter(
+    mlir::LLVMTypeConverter &converter, mlir::DataLayout &dataLayout,
+    llvm::function_ref<mlir::cir::LowerModule &()> getOrCreateLowerModule) {
+  converter.addConversion([&, getOrCreateLowerModule](
+                              mlir::cir::PointerType type) -> mlir::Type {
     // Drop pointee type since LLVM dialect only allows opaque pointers.
 
     auto addrSpace =
         mlir::cast_if_present<mlir::cir::AddressSpaceAttr>(type.getAddrSpace());
     // null addrspace attribute indicates the default addrspace
     if (!addrSpace)
       return mlir::LLVM::LLVMPointerType::get(type.getContext());
 
-    // TODO(cir): Query the target-specific address space map to lower other ASs
-    // like `opencl_private`.
-    assert(!MissingFeatures::targetLoweringInfoAddressSpaceMap());
-    assert(addrSpace.isTarget() && "NYI");
+    // Pass through target addrspace and map CIR addrspace to LLVM addrspace.
+    unsigned targetAS = addrSpace.isTarget()
+                            ? addrSpace.getTargetValue()
+                            : getOrCreateLowerModule()
+                                  .getTargetLoweringInfo()
+                                  .getCIRAddrSpaceMap()[addrSpace.getValue()];
 
-    return mlir::LLVM::LLVMPointerType::get(type.getContext(),
-                                            addrSpace.getTargetValue());
+    return mlir::LLVM::LLVMPointerType::get(type.getContext(), targetAS);
   });
   converter.addConversion([&](mlir::cir::DataMemberType type) -> mlir::Type {
     return mlir::IntegerType::get(type.getContext(),
@@ -3704,7 +3710,24 @@ void ConvertCIRToLLVMPass::runOnOperation() {
   auto module = getOperation();
   mlir::DataLayout dataLayout(module);
   mlir::LLVMTypeConverter converter(&getContext());
-  prepareTypeConverter(converter, dataLayout);
+
+  // If the triple is not present, e.g. CIR modules parsed from text, we
+  // cannot init LowerModule properly. Here we lazily init it as demand
+  // to not pay anything when we do not need it.
+  assert(!::cir::MissingFeatures::makeTripleAlwaysPresent());
+  std::mutex lowerModuleMtx;
+  std::unique_ptr<mlir::cir::LowerModule> lowerModule;
+  mlir::PatternRewriter rewriter{&getContext()};
+  auto getOrCreateLowerModule = [&]() -> mlir::cir::LowerModule & {
+    std::unique_lock lock(lowerModuleMtx, std::defer_lock);
+    if (getContext().isMultithreadingEnabled()) {
+      lock.lock();
+    }
+    if (!lowerModule)
+      lowerModule = mlir::cir::createLowerModule(module, rewriter);
+    return *lowerModule;
+  };
+  prepareTypeConverter(converter, dataLayout, getOrCreateLowerModule);
 
   mlir::RewritePatternSet patterns(&getContext());