--- /dev/null
+//===-- runtime/allocatable.h -----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Defines APIs for Fortran runtime library support of code generated
+// to manipulate and query allocatable variables, dummy arguments, & components.
+#ifndef FORTRAN_RUNTIME_ALLOCATABLE_H_
+#define FORTRAN_RUNTIME_ALLOCATABLE_H_
+#include "descriptor.h"
+#include "entry-names.h"
+
+namespace Fortran::runtime {
+extern "C" {
+
+// Initializes the descriptor for an allocatable of intrinsic or derived type.
+// The incoming descriptor is treated as (and can be) uninitialized garbage.
+// Must be called for each allocatable variable as its scope comes into being.
+// The storage for the allocatable's descriptor must have already been
+// allocated to a size sufficient for the rank, corank, and type.
+// A descriptor must be initialized before being used for any purpose,
+// but needs reinitialization in a deallocated state only when there is
+// a change of type, rank, or corank.
+void RTNAME(AllocatableInitIntrinsic)(
+ Descriptor &, TypeCategory, int kind, int rank = 0, int corank = 0);
+void RTNAME(AllocatableInitCharacter)(Descriptor &, SubscriptValue length,
+ int kind = 1, int rank = 0, int corank = 0);
+void RTNAME(AllocatableInitDerived)(
+ Descriptor &, const DerivedType &, int rank = 0, int corank = 0);
+
+// Checks that an allocatable is not already allocated in statements
+// with STAT=. Use this on a value descriptor before setting bounds or
+// type parameters. Not necessary on a freshly initialized descriptor.
+// (If there's no STAT=, the error will be caught later anyway, but
+// this API allows the error to be caught before descriptor is modified.)
+// Return 0 on success (deallocated state), else the STAT= value.
+int RTNAME(AllocatableCheckAllocated)(Descriptor &,
+ Descriptor *errMsg = nullptr, const char *sourceFile = nullptr,
+ int sourceLine = 0);
+
+// For MOLD= allocation; sets bounds, cobounds, and length type
+// parameters from another descriptor. The destination descriptor must
+// be initialized and deallocated.
+void RTNAME(AllocatableApplyMold)(Descriptor &, const Descriptor &mold);
+
+// Explicitly sets the bounds and length type parameters of an initialized
+// deallocated allocatable.
+void RTNAME(AllocatableSetBounds)(
+ Descriptor &, int zeroBasedDim, SubscriptValue lower, SubscriptValue upper);
+
+// The upper bound is ignored for the last codimension.
+void RTNAME(AllocatableSetCoBounds)(Descriptor &, int zeroBasedCoDim,
+ SubscriptValue lower, SubscriptValue upper = 0);
+
+// Length type parameters are indexed in declaration order; i.e., 0 is the
+// first length type parameter in the deepest base type. (Not for use
+// with CHARACTER; see above.)
+void RTNAME(AllocatableSetDerivedLength)(
+ Descriptor &, int which, SubscriptValue);
+
+// When an explicit type-spec appears in an ALLOCATE statement for an
+// allocatable with an explicit (non-deferred) length type paramater for
+// a derived type or CHARACTER value, the explicit value has to match
+// the length type parameter's value. This API checks that requirement.
+// Returns 0 for success, or the STAT= value on failure with hasStat==true.
+int RTNAME(AllocatableCheckLengthParameter)(Descriptor &,
+ int which /* 0 for CHARACTER length */, SubscriptValue other,
+ bool hasStat = false, Descriptor *errMsg = nullptr,
+ const char *sourceFile = nullptr, int sourceLine = 0);
+
+// Allocates an allocatable. The allocatable descriptor must have been
+// initialized and its bounds and length type parameters set and must be
+// in a deallocated state.
+// On failure, if hasStat is true, returns a nonzero error code for
+// STAT= and (if present) fills in errMsg; if hasStat is false, the
+// image is terminated. On success, leaves errMsg alone and returns zero.
+// Successfully allocated memory is initialized if the allocatable has a
+// derived type, and is always initialized by AllocatableAllocateSource().
+// Performs all necessary coarray synchronization and validation actions.
+int RTNAME(AllocatableAllocate)(Descriptor &, bool hasStat = false,
+ Descriptor *errMsg = nullptr, const char *sourceFile = nullptr,
+ int sourceLine = 0);
+int RTNAME(AllocatableAllocateSource)(Descriptor &, const Descriptor &source,
+ bool hasStat = false, Descriptor *errMsg = nullptr,
+ const char *sourceFile = nullptr, int sourceLine = 0);
+
+// Assigns to a whole allocatable, with automatic (re)allocation when the
+// destination is unallocated or nonconforming (Fortran 2003 semantics).
+// The descriptor must be initialized.
+// Recursively assigns components with (re)allocation as necessary.
+// TODO: Consider renaming to a more general name that will work for
+// assignments to pointers, dummy arguments, and anything else with a
+// descriptor.
+void RTNAME(AllocatableAssignment)(Descriptor &to, const Descriptor &from);
+
+// Implements the intrinsic subroutine MOVE_ALLOC (16.9.137 in F'2018,
+// but note the order of first two arguments is reversed for consistency
+// with the other APIs for allocatables.) The destination descriptor
+// must be initialized.
+int RTNAME(MoveAlloc)(Descriptor &to, const Descriptor &from,
+ bool hasStat = false, Descriptor *errMsg = nullptr,
+ const char *sourceFile = nullptr, int sourceLine = 0);
+
+// Deallocates an allocatable. Finalizes elements &/or components as needed.
+// The allocatable is left in an initialized state suitable for reallocation
+// with the same bounds, cobounds, and length type parameters.
+int RTNAME(AllocatableDeallocate)(Descriptor &, bool hasStat = false,
+ Descriptor *errMsg = nullptr, const char *sourceFile = nullptr,
+ int sourceLine = 0);
+}
+}
+#endif // FORTRAN_RUNTIME_ALLOCATABLE_H_