[flang][runtime] add LBOUND API for assumed-rank arrays (#94808)

Author: jeanPerier

flang/include/flang/Runtime/inquiry.h

@@ -24,9 +24,11 @@ extern "C" {
 std::int64_t RTDECL(LboundDim)(const Descriptor &array, int dim,
     const char *sourceFile = nullptr, int line = 0);
 
-void RTDECL(Shape)(void *result, const Descriptor &array, int kind,
+void RTDECL(Lbound)(void *result, const Descriptor &array, int kind,
     const char *sourceFile = nullptr, int line = 0);
 
+void RTDECL(Shape)(void *result, const Descriptor &array, int kind,
+    const char *sourceFile = nullptr, int line = 0);
 std::int64_t RTDECL(Size)(
     const Descriptor &array, const char *sourceFile = nullptr, int line = 0);
 

flang/runtime/inquiry.cpp

@@ -96,5 +96,16 @@ void RTDEF(Shape)(void *result, const Descriptor &array, int kind,
   }
 }
 
+void RTDEF(Lbound)(void *result, const Descriptor &array, int kind,
+    const char *sourceFile, int line) {
+  Terminator terminator{sourceFile, line};
+  INTERNAL_CHECK(array.rank() <= common::maxRank);
+  for (SubscriptValue i{0}; i < array.rank(); ++i) {
+    const Dimension &dimension{array.GetDimension(i)};
+    Fortran::runtime::ApplyIntegerKind<RawStoreIntegerAt, void>(
+        kind, terminator, result, i, dimension.LowerBound());
+  }
+}
+
 } // extern "C"
 } // namespace Fortran::runtime

flang/unittests/Runtime/Inquiry.cpp

@@ -14,7 +14,7 @@
 using namespace Fortran::runtime;
 using Fortran::common::TypeCategory;
 
-TEST(Inquiry, Lbound) {
+TEST(Inquiry, LboundDim) {
   // ARRAY  1 3 5
   //        2 4 6
   auto array{MakeArray<TypeCategory::Integer, 4>(
@@ -26,6 +26,42 @@ TEST(Inquiry, Lbound) {
   EXPECT_EQ(RTNAME(LboundDim)(*array, 2, __FILE__, __LINE__), std::int64_t{-1});
 }
 
+TEST(Inquiry, Lbound) {
+  // ARRAY  1 3 5
+  //        2 4 6
+  auto array{MakeArray<TypeCategory::Integer, 4>(
+      std::vector<int>{2, 3}, std::vector<std::int32_t>{1, 2, 3, 4, 5, 6})};
+  array->GetDimension(0).SetLowerBound(0);
+  array->GetDimension(1).SetLowerBound(-1);
+
+  // LBOUND(ARRAY, KIND=1)
+  auto int8Result{
+      MakeArray<TypeCategory::Integer, 1>(std::vector<int>{array->rank()},
+          std::vector<std::int8_t>(array->rank(), 0))};
+  RTNAME(Lbound)
+  (int8Result->raw().base_addr, *array, /*KIND=*/1, __FILE__, __LINE__);
+  EXPECT_EQ(*int8Result->ZeroBasedIndexedElement<std::int8_t>(0), 0);
+  EXPECT_EQ(*int8Result->ZeroBasedIndexedElement<std::int8_t>(1), -1);
+
+  // LBOUND(ARRAY, KIND=4)
+  auto int32Result{
+      MakeArray<TypeCategory::Integer, 4>(std::vector<int>{array->rank()},
+          std::vector<std::int32_t>(array->rank(), 0))};
+  RTNAME(Lbound)
+  (int32Result->raw().base_addr, *array, /*KIND=*/4, __FILE__, __LINE__);
+  EXPECT_EQ(*int32Result->ZeroBasedIndexedElement<std::int32_t>(0), 0);
+  EXPECT_EQ(*int32Result->ZeroBasedIndexedElement<std::int32_t>(1), -1);
+
+  // LBOUND(ARRAY, KIND=8)
+  auto int64Result{
+      MakeArray<TypeCategory::Integer, 8>(std::vector<int>{array->rank()},
+          std::vector<std::int64_t>(array->rank(), 0))};
+  RTNAME(Lbound)
+  (int64Result->raw().base_addr, *array, /*KIND=*/8, __FILE__, __LINE__);
+  EXPECT_EQ(*int64Result->ZeroBasedIndexedElement<std::int64_t>(0), 0);
+  EXPECT_EQ(*int64Result->ZeroBasedIndexedElement<std::int64_t>(1), -1);
+}
+
 TEST(Inquiry, Ubound) {
   // ARRAY  1 3 5
   //        2 4 6