From e38ef2ff711ca1aa68c541e973e68fbbb8efc575 Mon Sep 17 00:00:00 2001
From: Valentin Clement <clementval@gmail.com>
Date: Wed, 17 Nov 2021 12:01:57 +0100
Subject: [PATCH] [fir] Add fir.box_tdesc conversion

This patch adds the conversion pattern for
`fir.box_tdes`.

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

Reviewed By: kiranchandramohan

Differential Revision: https://reviews.llvm.org/D113931

Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
---
 flang/lib/Optimizer/CodeGen/CodeGen.cpp | 44 ++++++++++++++++++-------
 flang/test/Fir/convert-to-llvm.fir      | 17 ++++++++++
 2 files changed, 49 insertions(+), 12 deletions(-)

diff --git a/flang/lib/Optimizer/CodeGen/CodeGen.cpp b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
index 899315a1286e..4e12005777b4 100644
--- a/flang/lib/Optimizer/CodeGen/CodeGen.cpp
+++ b/flang/lib/Optimizer/CodeGen/CodeGen.cpp
@@ -498,6 +498,26 @@ struct StringLitOpConversion : public FIROpConversion<fir::StringLitOp> {
   }
 };
 
+/// Lower `fir.box_tdesc` to the sequence of operations to extract the type
+/// descriptor from the box.
+struct BoxTypeDescOpConversion : public FIROpConversion<fir::BoxTypeDescOp> {
+  using FIROpConversion::FIROpConversion;
+
+  mlir::LogicalResult
+  matchAndRewrite(fir::BoxTypeDescOp boxtypedesc, OpAdaptor adaptor,
+                  mlir::ConversionPatternRewriter &rewriter) const override {
+    mlir::Value box = adaptor.getOperands()[0];
+    auto loc = boxtypedesc.getLoc();
+    mlir::Type typeTy =
+        fir::getDescFieldTypeModel<kTypePosInBox>()(boxtypedesc.getContext());
+    auto result = getValueFromBox(loc, box, typeTy, rewriter, kTypePosInBox);
+    auto typePtrTy = mlir::LLVM::LLVMPointerType::get(typeTy);
+    rewriter.replaceOpWithNewOp<mlir::LLVM::IntToPtrOp>(boxtypedesc, typePtrTy,
+                                                        result);
+    return success();
+  }
+};
+
 // `fir.call` -> `llvm.call`
 struct CallOpConversion : public FIROpConversion<fir::CallOp> {
   using FIROpConversion::FIROpConversion;
@@ -1664,18 +1684,18 @@ public:
         AllocaOpConversion, BoxAddrOpConversion, BoxCharLenOpConversion,
         BoxDimsOpConversion, BoxEleSizeOpConversion, BoxIsAllocOpConversion,
         BoxIsArrayOpConversion, BoxIsPtrOpConversion, BoxRankOpConversion,
-        CallOpConversion, CmpcOpConversion, ConvertOpConversion,
-        DispatchOpConversion, DispatchTableOpConversion, DTEntryOpConversion,
-        DivcOpConversion, EmboxCharOpConversion, ExtractValueOpConversion,
-        HasValueOpConversion, GenTypeDescOpConversion, GlobalLenOpConversion,
-        GlobalOpConversion, InsertOnRangeOpConversion, InsertValueOpConversion,
-        IsPresentOpConversion, LoadOpConversion, NegcOpConversion,
-        MulcOpConversion, SelectCaseOpConversion, SelectOpConversion,
-        SelectRankOpConversion, SelectTypeOpConversion, ShapeOpConversion,
-        ShapeShiftOpConversion, ShiftOpConversion, SliceOpConversion,
-        StoreOpConversion, StringLitOpConversion, SubcOpConversion,
-        UnboxCharOpConversion, UndefOpConversion, UnreachableOpConversion,
-        ZeroOpConversion>(typeConverter);
+        BoxTypeDescOpConversion, CallOpConversion, CmpcOpConversion,
+        ConvertOpConversion, DispatchOpConversion, DispatchTableOpConversion,
+        DTEntryOpConversion, DivcOpConversion, EmboxCharOpConversion,
+        ExtractValueOpConversion, HasValueOpConversion, GenTypeDescOpConversion,
+        GlobalLenOpConversion, GlobalOpConversion, InsertOnRangeOpConversion,
+        InsertValueOpConversion, IsPresentOpConversion, LoadOpConversion,
+        NegcOpConversion, MulcOpConversion, SelectCaseOpConversion,
+        SelectOpConversion, SelectRankOpConversion, SelectTypeOpConversion,
+        ShapeOpConversion, ShapeShiftOpConversion, ShiftOpConversion,
+        SliceOpConversion, StoreOpConversion, StringLitOpConversion,
+        SubcOpConversion, UnboxCharOpConversion, UndefOpConversion,
+        UnreachableOpConversion, ZeroOpConversion>(typeConverter);
     mlir::populateStdToLLVMConversionPatterns(typeConverter, pattern);
     mlir::arith::populateArithmeticToLLVMConversionPatterns(typeConverter,
                                                             pattern);
diff --git a/flang/test/Fir/convert-to-llvm.fir b/flang/test/Fir/convert-to-llvm.fir
index 5cbee8165382..8465063312c8 100644
--- a/flang/test/Fir/convert-to-llvm.fir
+++ b/flang/test/Fir/convert-to-llvm.fir
@@ -1319,3 +1319,20 @@ func @dead_slice() {
 // CHECK-NOT: fir.slice
 // CHECK: %{{.*}} = llvm.mlir.constant(0 : index) : i{{.*}}
 // CHECK-NEXT: llvm.return
+
+// -----
+
+// Test `fir.box_tdesc` conversion.
+
+func @box_tdesc(%arg0: !fir.box<f64>) {
+  %0 = fir.box_tdesc %arg0 : (!fir.box<f64>) -> !fir.tdesc<f64>
+  return
+}
+
+// CHECK-LABEL: llvm.func @box_tdesc(
+// CHECK-SAME:                       %[[ARG0:.*]]: !llvm.ptr<struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}})>>) {
+// CHECK:         %[[C0:.*]] = llvm.mlir.constant(0 : i32) : i32
+// CHECK:         %[[TYPE_POS:.*]] = llvm.mlir.constant(4 : i32) : i32
+// CHECK:         %[[GEP:.*]] = llvm.getelementptr %[[ARG0]][%[[C0]], %[[TYPE_POS]]] : (!llvm.ptr<struct<(ptr<f64>, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}}, i{{.*}})>>, i32, i32) -> !llvm.ptr<i8>
+// CHECK:         %[[LOAD:.*]] = llvm.load %[[GEP]] : !llvm.ptr<i{{.*}}>
+// CHECK:         %{{.*}} = llvm.inttoptr %[[LOAD]] : i{{.*}} to !llvm.ptr<i{{.*}}>