[fir] !fir.tdesc type conversion

[clementval]

Summary

Add !fir.tdesc type conversion.
!fir.tdesc is converted to a llvm.ptr<i8>.

This patch is part of the upstreaming effort from fir-dev branch.

Co-authored-by: Eric Schweitz <[e-mail]>
Co-authored-by: Jean Perier <[e-mail]>

[awarzynski]

flang/lib/Optimizer/CodeGen/TypeConverter.h

290–291

What's the f18 object?

[kiranchandramohan]

Nit: Although these are all converted to i8 pointers, it might be good to have a few more tests? I have given a few below.

$ ./bin/fir-opt --fir-to-llvm-ir tdesc.mlir

module {

llvm.func @foo1(!llvm.ptr<i8>) attributes {sym_visibility = "private"}
llvm.func @foo2(!llvm.ptr<i8>) attributes {sym_visibility = "private"}
llvm.func @foo3(!llvm.ptr<i8>) attributes {sym_visibility = "private"}

}

$ cat tdesc.mlir

func private @foo1(%arg : !fir.tdesc<!fir.array<100xf32>>)
func private @foo2(%arg : !fir.tdesc<f32>)
func private @foo3(%arg : !fir.tdesc<!fir.type<derived7{f1:f32,f2:f32}>>)

[clementval]

In D113769#3127443, @kiranchandramohan wrote:

Nit: Although these are all converted to i8 pointers, it might be good to have a few more tests? I have given a few below.

$ ./bin/fir-opt --fir-to-llvm-ir tdesc.mlir

module {

llvm.func @foo1(!llvm.ptr<i8>) attributes {sym_visibility = "private"}
llvm.func @foo2(!llvm.ptr<i8>) attributes {sym_visibility = "private"}
llvm.func @foo3(!llvm.ptr<i8>) attributes {sym_visibility = "private"}

}

$ cat tdesc.mlir

func private @foo1(%arg : !fir.tdesc<!fir.array<100xf32>>)
func private @foo2(%arg : !fir.tdesc<f32>)
func private @foo3(%arg : !fir.tdesc<!fir.type<derived7{f1:f32,f2:f32}>>)

I'll add your tests.

flang/lib/Optimizer/CodeGen/TypeConverter.h

290–291

Not the original author of this comment but I guess it refers to type vs. class.

[clementval]

Rebase + add tests

[schweitz]

flang/lib/Optimizer/CodeGen/TypeConverter.h

290–291

Correct.

An entity of derived type (an object), can need both an "is_a" test (is this object exactly class B) and a subclassing test (is this object of some class D which is or is derived from B).

Clearly a trivial pointer comparison of the type descriptor of the entity/object is insufficient to implement both of these tests.

[kiranchandramohan]

LGTM.

flang/lib/Optimizer/CodeGen/TypeConverter.h

addConversion(
         [&](fir::ComplexType cmplx) { return convertComplexType(cmplx); });
     addConversion(
         [&](fir::RealType real) { return convertRealType(real.getFKind()); });
     addConversion(
         [&](fir::ReferenceType ref) { return convertPointerLike(ref); });
     addConversion([&](fir::SequenceType sequence) {
       return convertSequenceType(sequence);
     });
+    addConversion([&](fir::TypeDescType tdesc) {
+      return convertTypeDescType(tdesc.getContext());
+    });
     addConversion([&](fir::VectorType vecTy) {
       return mlir::VectorType::get(llvm::ArrayRef<int64_t>(vecTy.getLen()),
                                    convertType(vecTy.getEleTy()));
     });
     addConversion([&](mlir::TupleType tuple) {
       LLVM_DEBUG(llvm::dbgs() << "type convert: " << tuple << '\n');
       llvm::SmallVector<mlir::Type> inMembers;
       tuple.getFlattenedTypes(inMembers);
if (constRows) {
           break;
       }
       if (seq.hasConstantShape())
         return baseTy;
     }
     return mlir::LLVM::LLVMPointerType::get(baseTy);
   }
 
+  // fir.tdesc<any>  -->  llvm<"i8*">
+  // TODO: For now use a void*, however pointer identity is not sufficient for
+  // the f18 object v. class distinction (F2003).
+  mlir::Type convertTypeDescType(mlir::MLIRContext *ctx) {
+    return mlir::LLVM::LLVMPointerType::get(
+        mlir::IntegerType::get(&getContext(), 8));
+  }
+
   /// Convert llvm::Type::TypeID to mlir::Type
   mlir::Type fromRealTypeID(llvm::Type::TypeID typeID, fir::KindTy kind) {
     switch (typeID) {
     case llvm::Type::TypeID::HalfTyID:
       return mlir::FloatType::getF16(&getContext());
     case llvm::Type::TypeID::BFloatTyID:
       return mlir::FloatType::getBF16(&getContext());
     case llvm::Type::TypeID::FloatTyID:

flang/test/Fir/types-to-llvm.fir

 
 // -----
 
 // Test `!fir.len` conversion.
 
 func private @foo0(%arg0: !fir.len)
 // CHECK-LABEL: foo0
 // CHECK-SAME: i64
+
+// -----
+
+// Test `!fir.tdesc` conversion.
+
+func private @foo0(%arg0: !fir.tdesc<!fir.type<x>>)
+// CHECK-LABEL: foo0
+// CHECK-SAME:  !llvm.ptr<i8>
+
+func private @foo1(%arg : !fir.tdesc<!fir.array<100xf32>>)
+// CHECK-LABEL: foo1
+// CHECK-SAME:  !llvm.ptr<i8>
+
+func private @foo2(%arg : !fir.tdesc<f32>)
+// CHECK-LABEL: foo2
+// CHECK-SAME:  !llvm.ptr<i8>
+
+func private @foo3(%arg : !fir.tdesc<!fir.type<derived7{f1:f32,f2:f32}>>)
+// CHECK-LABEL: foo3
+// CHECK-SAME:  !llvm.ptr<i8>