[CIR][CIRGen][LowerToLLVM] Add address space attribute for pointer type (#606)

This is the prelude of address space support. Linked issue: #418 .

- Add the attribute and implement asm format & type conversion.
- Make ops like `cir.global` and `cir.get_global` aware of address space, and solve the latter flag.
- Relax the restriction of default alloca address space. Then we can use correct address spaces for languages like OpenCL in future.

Author: seven-mile

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

@@ -208,9 +208,25 @@ def CIR_PointerType : CIR_Type<"Pointer", "ptr",
     `CIR.ptr` is a type returned by any op generating a pointer in C++.
   }];
 
-  let parameters = (ins "mlir::Type":$pointee);
+  let parameters = (ins "mlir::Type":$pointee,
+                        DefaultValuedParameter<"unsigned", "0">:$addrSpace);
 
-  let assemblyFormat = "`<` $pointee `>`";
+  let builders = [
+    TypeBuilderWithInferredContext<(ins
+      "mlir::Type":$pointee, CArg<"unsigned", "0">:$addrSpace), [{
+      return Base::get(pointee.getContext(), pointee, addrSpace);
+    }]>,
+    TypeBuilder<(ins
+      "mlir::Type":$pointee, CArg<"unsigned", "0">:$addrSpace), [{
+      return Base::get($_ctxt, pointee, addrSpace);
+    }]>,
+  ];
+
+  let assemblyFormat = [{
+    `<` $pointee ( `,` `addrspace` `(` $addrSpace^ `)` )? `>`
+  }];
+
+  let skipDefaultBuilders = 1;
 
   let extraClassDeclaration = [{
     bool isVoidPtr() const {

clang/lib/CIR/CodeGen/CIRGenTypes.cpp

@@ -598,9 +598,9 @@ mlir::Type CIRGenTypes::ConvertType(QualType T) {
     const ReferenceType *RTy = cast<ReferenceType>(Ty);
     QualType ETy = RTy->getPointeeType();
     auto PointeeType = convertTypeForMem(ETy);
-    // TODO(cir): use Context.getTargetAddressSpace(ETy) on pointer
-    ResultType =
-        ::mlir::cir::PointerType::get(Builder.getContext(), PointeeType);
+    ResultType = ::mlir::cir::PointerType::get(
+        Builder.getContext(), PointeeType,
+        Context.getTargetAddressSpace(ETy.getAddressSpace()));
     assert(ResultType && "Cannot get pointer type?");
     break;
   }
@@ -615,9 +615,9 @@ mlir::Type CIRGenTypes::ConvertType(QualType T) {
     // if (PointeeType->isVoidTy())
     //  PointeeType = Builder.getI8Type();
 
-    // FIXME: add address specifier to cir::PointerType?
-    ResultType =
-        ::mlir::cir::PointerType::get(Builder.getContext(), PointeeType);
+    ResultType = ::mlir::cir::PointerType::get(
+        Builder.getContext(), PointeeType,
+        Context.getTargetAddressSpace(ETy.getAddressSpace()));
     assert(ResultType && "Cannot get pointer type?");
     break;
   }

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

@@ -3182,7 +3182,8 @@ void prepareTypeConverter(mlir::LLVMTypeConverter &converter,
                           mlir::DataLayout &dataLayout) {
   converter.addConversion([&](mlir::cir::PointerType type) -> mlir::Type {
     // Drop pointee type since LLVM dialect only allows opaque pointers.
-    return mlir::LLVM::LLVMPointerType::get(type.getContext());
+    return mlir::LLVM::LLVMPointerType::get(type.getContext(),
+                                            type.getAddrSpace());
   });
   converter.addConversion([&](mlir::cir::ArrayType type) -> mlir::Type {
     auto ty = converter.convertType(type.getEltType());

clang/test/CIR/CodeGen/address-space.c

@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CIR
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -S -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=LLVM
+// XFAIL: *
+
+// CIR: cir.func {{@.*foo.*}}(%arg0: !cir.ptr<!s32i, addrspace(1)>
+// LLVM: define void @foo(ptr addrspace(1) %0)
+void foo(int __attribute__((address_space(1))) *arg) {
+  return;
+}

clang/test/CIR/IR/address-space.cir

@@ -0,0 +1,11 @@
+// RUN: cir-opt %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s
+
+!s32i = !cir.int<s, 32>
+
+module {
+  // CHECK: @test_addrspace_assembly_format(%arg0: !cir.ptr<!s32i>)
+  cir.func @test_addrspace_assembly_format(%arg0: !cir.ptr<!s32i, addrspace(0)>) {
+    cir.return
+  }
+}

clang/test/CIR/Lowering/address-space.cir

@@ -0,0 +1,20 @@
+// RUN: cir-translate %s -cir-to-llvmir -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s -check-prefix=LLVM
+
+!s32i = !cir.int<s, 32>
+
+module  {
+  // LLVM: define void @foo(ptr %0)
+  cir.func @foo(%arg0: !cir.ptr<!s32i>) {
+    // LLVM-NEXT: alloca ptr,
+    %0 = cir.alloca !cir.ptr<!s32i>, !cir.ptr<!cir.ptr<!s32i>>, ["arg", init] {alignment = 8 : i64}
+    cir.return
+  }
+
+  // LLVM: define void @bar(ptr addrspace(1) %0)
+  cir.func @bar(%arg0: !cir.ptr<!s32i, addrspace(1)>) {
+    // LLVM-NEXT: alloca ptr addrspace(1)
+    %0 = cir.alloca !cir.ptr<!s32i, addrspace(1)>, !cir.ptr<!cir.ptr<!s32i, addrspace(1)>>, ["arg", init] {alignment = 8 : i64}
+    cir.return
+  }
+}