[clang] [flang] [Flang] LoongArch64 support for BIND(C) derived types in mabi=lp64d. (PR #117108)

[Lu Weining via cfe-commits]

================
@@ -1151,6 +1154,317 @@ struct TargetLoongArch64 : public GenericTarget<TargetLoongArch64> {
 
     return GenericTarget::integerArgumentType(loc, argTy);
   }
+
+  /// Flatten non-basic types, resulting in an array of types containing only
+  /// `IntegerType` and `FloatType`.
+  std::vector<mlir::Type> flattenTypeList(mlir::Location loc,
+                                          const mlir::Type type) const {
+    std::vector<mlir::Type> flatTypes;
+
+    llvm::TypeSwitch<mlir::Type>(type)
+        .template Case<mlir::IntegerType>([&](mlir::IntegerType intTy) {
+          if (intTy.getWidth() != 0)
+            flatTypes.push_back(intTy);
+        })
+        .template Case<mlir::FloatType>([&](mlir::FloatType floatTy) {
+          if (floatTy.getWidth() != 0)
+            flatTypes.push_back(floatTy);
+        })
+        .template Case<mlir::ComplexType>([&](mlir::ComplexType cmplx) {
+          const auto *sem = &floatToSemantics(kindMap, cmplx.getElementType());
+          if (sem == &llvm::APFloat::IEEEsingle() ||
+              sem == &llvm::APFloat::IEEEdouble() ||
+              sem == &llvm::APFloat::IEEEquad())
+            std::fill_n(std::back_inserter(flatTypes), 2,
+                        cmplx.getElementType());
+          else
+            TODO(loc, "unsupported complx type(not IEEEsingle, IEEEdouble, "
+                      "IEEEquad) as a structure component for BIND(C), "
+                      "VALUE derived type argument and type return");
+        })
+        .template Case<fir::LogicalType>([&](fir::LogicalType logicalTy) {
+          const unsigned width =
+              kindMap.getLogicalBitsize(logicalTy.getFKind());
+          if (width != 0)
+            flatTypes.push_back(
+                mlir::IntegerType::get(type.getContext(), width));
+        })
+        .template Case<fir::CharacterType>([&](fir::CharacterType charTy) {
+          assert(kindMap.getCharacterBitsize(charTy.getFKind()) <= 8 &&
+                 "the bit size of characterType as an interoperable type must "
+                 "not exceed 8");
+          for (unsigned i = 0; i < charTy.getLen(); ++i)
+            flatTypes.push_back(mlir::IntegerType::get(type.getContext(), 8));
+        })
+        .template Case<fir::SequenceType>([&](fir::SequenceType seqTy) {
+          if (!seqTy.hasDynamicExtents()) {
+            std::size_t numOfEle = seqTy.getConstantArraySize();
+            mlir::Type eleTy = seqTy.getEleTy();
+            if (!mlir::isa<mlir::IntegerType, mlir::FloatType>(eleTy)) {
+              std::vector<mlir::Type> subTypeList = flattenTypeList(loc, eleTy);
+              if (subTypeList.size() != 0)
+                for (std::size_t i = 0; i < numOfEle; ++i)
+                  llvm::copy(subTypeList, std::back_inserter(flatTypes));
+            } else {
+              std::fill_n(std::back_inserter(flatTypes), numOfEle, eleTy);
+            }
+          } else
+            TODO(loc, "unsupported dynamic extent sequence type as a structure "
+                      "component for BIND(C), "
+                      "VALUE derived type argument and type return");
+        })
+        .template Case<fir::RecordType>([&](fir::RecordType recTy) {
+          for (auto &component : recTy.getTypeList()) {
+            mlir::Type eleTy = component.second;
+            std::vector<mlir::Type> subTypeList = flattenTypeList(loc, eleTy);
+            if (subTypeList.size() != 0)
+              llvm::copy(subTypeList, std::back_inserter(flatTypes));
+          }
+        })
+        .template Case<fir::VectorType>([&](fir::VectorType vecTy) {
----------------
SixWeining wrote:

Vector should not be handled here. The psABI doesn't rule how vector is passed. What clang did is that vector is passed by ref but no by register (neither FPRs nor vector regs).

https://github.com/llvm/llvm-project/pull/117108