[mlir][LLVM] Support opaque pointers in llvm.mlir.addressof

The verifier of llvm.mlir.addressof did not properly account for opaque pointers, that is, the pointer type not having an element type equal to the type of the referenced global or function. This patch fixes that by skipping the test for the element type if the pointer is opaque.

Differential Revision: https://reviews.llvm.org/D124333

mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td

@@ -92,7 +92,7 @@ def LLVM_AnyFloat : Type<
 
 // Type constraint accepting any LLVM pointer type.
 def LLVM_AnyPointer : Type<CPred<"$_self.isa<::mlir::LLVM::LLVMPointerType>()">,
-                          "LLVM pointer type">;
+                          "LLVM pointer type", "::mlir::LLVM::LLVMPointerType">;
 
 // Type constraint accepting LLVM pointer type with an additional constraint
 // on the element type.
@@ -103,7 +103,7 @@ class LLVM_PointerTo<Type pointee> : Type<
              "$_self",
              "$_self.cast<::mlir::LLVM::LLVMPointerType>().getElementType()",
              pointee.predicate>]>]>,
-  "LLVM pointer to " # pointee.summary>;
+  "LLVM pointer to " # pointee.summary, "::mlir::LLVM::LLVMPointerType">;
 
 // Type constraints accepting LLVM pointer type to integer of a specific width.
 class LLVM_IntPtrBase<int width, int addressSpace = 0> : Type<

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

@@ -827,7 +827,7 @@ def UnnamedAddr : LLVM_EnumAttr<
 
 def LLVM_AddressOfOp : LLVM_Op<"mlir.addressof", [NoSideEffect]> {
   let arguments = (ins FlatSymbolRefAttr:$global_name);
-  let results = (outs LLVM_Type:$res);
+  let results = (outs LLVM_AnyPointer:$res);
 
   let summary = "Creates a pointer pointing to a global or a function";
 

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

@@ -1654,14 +1654,19 @@ LogicalResult AddressOfOp::verify() {
     return emitOpError(
         "must reference a global defined by 'llvm.mlir.global' or 'llvm.func'");
 
-  if (global &&
-      LLVM::LLVMPointerType::get(global.getType(), global.getAddrSpace()) !=
-          getResult().getType())
+  LLVMPointerType type = getType();
+  if (global && global.getAddrSpace() != type.getAddressSpace())
+    return emitOpError("pointer address space must match address space of the "
+                       "referenced global");
+
+  if (type.isOpaque())
+    return success();
+
+  if (global && type.getElementType() != global.getType())
     return emitOpError(
         "the type must be a pointer to the type of the referenced global");
 
-  if (function && LLVM::LLVMPointerType::get(function.getFunctionType()) !=
-                      getResult().getType())
+  if (function && type.getElementType() != function.getFunctionType())
     return emitOpError(
         "the type must be a pointer to the type of the referenced function");
 

mlir/test/Dialect/LLVMIR/global.mlir

@@ -61,6 +61,8 @@ llvm.mlir.global weak_odr @weak_odr() : i64
 llvm.mlir.global external @has_thr_local(42 : i64) {thr_local} : i64
 // CHECK: llvm.mlir.global external @has_dso_local(42 : i64) {dso_local} : i64
 llvm.mlir.global external @has_dso_local(42 : i64) {dso_local} : i64
+// CHECK: llvm.mlir.global external @has_addr_space(32 : i64) {addr_space = 3 : i32} : i64
+llvm.mlir.global external @has_addr_space(32 : i64) {addr_space = 3: i32} : i64
 
 // CHECK-LABEL: references
 func.func @references() {
@@ -70,6 +72,12 @@ func.func @references() {
   // CHECK: llvm.mlir.addressof @".string" : !llvm.ptr<array<6 x i8>>
   %1 = llvm.mlir.addressof @".string" : !llvm.ptr<array<6 x i8>>
 
+  // CHECK: llvm.mlir.addressof @global : !llvm.ptr
+  %2 = llvm.mlir.addressof @global : !llvm.ptr
+
+  // CHECK: llvm.mlir.addressof @has_addr_space : !llvm.ptr<3>
+  %3 = llvm.mlir.addressof @has_addr_space : !llvm.ptr<3>
+
   llvm.return
 }
 
@@ -201,17 +209,25 @@ llvm.mlir.global internal @g(43 : i64) : i64 {
 
 llvm.mlir.global internal @g(32 : i64) {addr_space = 3: i32} : i64
 func.func @mismatch_addr_space_implicit_global() {
-  // expected-error @+1 {{op the type must be a pointer to the type of the referenced global}}
+  // expected-error @+1 {{pointer address space must match address space of the referenced global}}
   llvm.mlir.addressof @g : !llvm.ptr<i64>
 }
 
 // -----
 
 llvm.mlir.global internal @g(32 : i64) {addr_space = 3: i32} : i64
 func.func @mismatch_addr_space() {
-  // expected-error @+1 {{op the type must be a pointer to the type of the referenced global}}
+  // expected-error @+1 {{pointer address space must match address space of the referenced global}}
   llvm.mlir.addressof @g : !llvm.ptr<i64, 4>
 }
+// -----
+
+llvm.mlir.global internal @g(32 : i64) {addr_space = 3: i32} : i64
+
+func.func @mismatch_addr_space_opaque() {
+  // expected-error @+1 {{pointer address space must match address space of the referenced global}}
+  llvm.mlir.addressof @g : !llvm.ptr<4>
+}
 
 // -----
 

mlir/test/Dialect/LLVMIR/invalid.mlir

@@ -508,7 +508,7 @@ func.func @invalid_vector_type_5(%a : vector<4xf32>, %idx : i32) -> vector<4xf32
 // -----
 
 func.func @null_non_llvm_type() {
-  // expected-error@+1 {{must be LLVM pointer type, but got 'i32'}}
+  // expected-error@+1 {{custom op 'llvm.mlir.null' invalid kind of type specified}}
   llvm.mlir.null : i32
 }