1//===-- lib/Evaluate/host.h -------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef FORTRAN_EVALUATE_HOST_H_
10#define FORTRAN_EVALUATE_HOST_H_
11
12// Define a compile-time mapping between Fortran intrinsic types and host
13// hardware types if possible. The purpose is to avoid having to do any kind of
14// assumption on whether a "float" matches the Scalar<Type<TypeCategory::Real,
15// 4>> outside of this header. The main tools are HostTypeExists<T> and
16// HostType<T>. HostTypeExists<T>() will return true if and only if a host
17// hardware type maps to Fortran intrinsic type T. Then HostType<T> can be used
18// to safely refer to this hardware type.
19
20#if HAS_QUADMATHLIB
21#include "quadmath_wrapper.h"
22#include "flang/Common/float128.h"
23#endif
24#include "flang/Evaluate/type.h"
25#include <cfenv>
26#include <complex>
27#include <cstdint>
28#include <limits>
29#include <string>
30#include <type_traits>
31
32namespace Fortran::evaluate {
33namespace host {
34
35// Helper class to handle host runtime traps, status flag and errno
36class HostFloatingPointEnvironment {
37public:
38 void SetUpHostFloatingPointEnvironment(FoldingContext &);
39 void CheckAndRestoreFloatingPointEnvironment(FoldingContext &);
40 bool hasSubnormalFlushingHardwareControl() const {
41 return hasSubnormalFlushingHardwareControl_;
42 }
43 void SetFlag(RealFlag flag) { flags_.set(flag); }
44 bool hardwareFlagsAreReliable() const { return hardwareFlagsAreReliable_; }
45
46private:
47 std::fenv_t originalFenv_;
48#if __x86_64__
49 unsigned int originalMxcsr;
50#endif
51 RealFlags flags_;
52 bool hasSubnormalFlushingHardwareControl_{false};
53 bool hardwareFlagsAreReliable_{true};
54};
55
56// Type mapping from F18 types to host types
57struct UnsupportedType {}; // There is no host type for the F18 type
58
59template <typename FTN_T> struct HostTypeHelper {
60 using Type = UnsupportedType;
61};
62template <typename FTN_T> using HostType = typename HostTypeHelper<FTN_T>::Type;
63
64template <typename... T> constexpr inline bool HostTypeExists() {
65 return (... && (!std::is_same_v<HostType<T>, UnsupportedType>));
66}
67
68// Type mapping from host types to F18 types FortranType<HOST_T> is defined
69// after all HosTypeHelper definition because it reverses them to avoid
70// duplication.
71
72// Scalar conversion utilities from host scalars to F18 scalars
73template <typename FTN_T>
74inline constexpr Scalar<FTN_T> CastHostToFortran(const HostType<FTN_T> &x) {
75 static_assert(HostTypeExists<FTN_T>());
76 if constexpr (FTN_T::category == TypeCategory::Complex &&
77 sizeof(Scalar<FTN_T>) != sizeof(HostType<FTN_T>)) {
78 // X87 is usually padded to 12 or 16bytes. Need to cast piecewise for
79 // complex
80 return Scalar<FTN_T>{CastHostToFortran<typename FTN_T::Part>(std::real(x)),
81 CastHostToFortran<typename FTN_T::Part>(std::imag(x))};
82 } else {
83 return *reinterpret_cast<const Scalar<FTN_T> *>(&x);
84 }
85}
86
87// Scalar conversion utilities from F18 scalars to host scalars.
88template <typename FTN_T>
89inline constexpr HostType<FTN_T> CastFortranToHost(const Scalar<FTN_T> &x) {
90 static_assert(HostTypeExists<FTN_T>());
91 if constexpr (FTN_T::category == TypeCategory::Complex) {
92 using FortranPartType = typename FTN_T::Part;
93 return HostType<FTN_T>{CastFortranToHost<FortranPartType>(x.REAL()),
94 CastFortranToHost<FortranPartType>(x.AIMAG())};
95 } else if constexpr (std::is_same_v<FTN_T, Type<TypeCategory::Real, 10>>) {
96 // x87 80-bit floating-point occupies 16 bytes as a C "long double";
97 // copy the data to avoid a legitimate (but benign due to little-endianness)
98 // warning from GCC >= 11.2.0.
99 HostType<FTN_T> y;
100 std::memcpy(&y, &x, sizeof x);
101 return y;
102 } else {
103 static_assert(sizeof x == sizeof(HostType<FTN_T>));
104 return *reinterpret_cast<const HostType<FTN_T> *>(&x);
105 }
106}
107
108template <> struct HostTypeHelper<Type<TypeCategory::Integer, 1>> {
109 using Type = std::int8_t;
110};
111
112template <> struct HostTypeHelper<Type<TypeCategory::Integer, 2>> {
113 using Type = std::int16_t;
114};
115
116template <> struct HostTypeHelper<Type<TypeCategory::Integer, 4>> {
117 using Type = std::int32_t;
118};
119
120template <> struct HostTypeHelper<Type<TypeCategory::Integer, 8>> {
121 using Type = std::int64_t;
122};
123
124template <> struct HostTypeHelper<Type<TypeCategory::Integer, 16>> {
125#if (defined(__GNUC__) || defined(__clang__)) && defined(__SIZEOF_INT128__)
126 using Type = __int128_t;
127#else
128 using Type = UnsupportedType;
129#endif
130};
131
132// TODO no mapping to host types are defined currently for 16bits float
133// It should be defined when gcc/clang have a better support for it.
134
135template <>
136struct HostTypeHelper<
137 Type<TypeCategory::Real, common::RealKindForPrecision(24)>> {
138 // IEEE 754 32bits
139 using Type = std::conditional_t<sizeof(float) == 4 &&
140 std::numeric_limits<float>::is_iec559,
141 float, UnsupportedType>;
142};
143
144template <>
145struct HostTypeHelper<
146 Type<TypeCategory::Real, common::RealKindForPrecision(53)>> {
147 // IEEE 754 64bits
148 using Type = std::conditional_t<sizeof(double) == 8 &&
149 std::numeric_limits<double>::is_iec559,
150 double, UnsupportedType>;
151};
152
153template <>
154struct HostTypeHelper<
155 Type<TypeCategory::Real, common::RealKindForPrecision(64)>> {
156 // X87 80bits
157 using Type = std::conditional_t<sizeof(long double) >= 10 &&
158 std::numeric_limits<long double>::digits == 64 &&
159 std::numeric_limits<long double>::max_exponent == 16384,
160 long double, UnsupportedType>;
161};
162
163#if HAS_QUADMATHLIB
164template <> struct HostTypeHelper<Type<TypeCategory::Real, 16>> {
165 // IEEE 754 128bits
166 using Type = __float128;
167};
168#else
169template <> struct HostTypeHelper<Type<TypeCategory::Real, 16>> {
170 // IEEE 754 128bits
171 using Type = std::conditional_t<sizeof(long double) == 16 &&
172 std::numeric_limits<long double>::digits == 113 &&
173 std::numeric_limits<long double>::max_exponent == 16384,
174 long double, UnsupportedType>;
175};
176#endif
177
178template <int KIND> struct HostTypeHelper<Type<TypeCategory::Complex, KIND>> {
179 using RealT = Fortran::evaluate::Type<TypeCategory::Real, KIND>;
180 using Type = std::conditional_t<HostTypeExists<RealT>(),
181 std::complex<HostType<RealT>>, UnsupportedType>;
182};
183
184#if HAS_QUADMATHLIB
185template <> struct HostTypeHelper<Type<TypeCategory::Complex, 16>> {
186 using RealT = Fortran::evaluate::Type<TypeCategory::Real, 16>;
187 using Type = __complex128;
188};
189#endif
190
191template <int KIND> struct HostTypeHelper<Type<TypeCategory::Logical, KIND>> {
192 using Type = std::conditional_t<KIND <= 8, std::uint8_t, UnsupportedType>;
193};
194
195template <int KIND> struct HostTypeHelper<Type<TypeCategory::Character, KIND>> {
196 using Type =
197 Scalar<typename Fortran::evaluate::Type<TypeCategory::Character, KIND>>;
198};
199
200// Type mapping from host types to F18 types. This need to be placed after all
201// HostTypeHelper specializations.
202template <typename T, typename... TT> struct IndexInTupleHelper {};
203template <typename T, typename... TT>
204struct IndexInTupleHelper<T, std::tuple<TT...>> {
205 static constexpr int value{common::TypeIndex<T, TT...>};
206};
207struct UnknownType {}; // the host type does not match any F18 types
208template <typename HOST_T> struct FortranTypeHelper {
209 using HostTypeMapping =
210 common::MapTemplate<HostType, AllIntrinsicTypes, std::tuple>;
211 static constexpr int index{
212 IndexInTupleHelper<HOST_T, HostTypeMapping>::value};
213 // Both conditional types are "instantiated", so a valid type must be
214 // created for invalid index even if not used.
215 using Type = std::conditional_t<index >= 0,
216 std::tuple_element_t<(index >= 0) ? index : 0, AllIntrinsicTypes>,
217 UnknownType>;
218};
219
220template <typename HOST_T>
221using FortranType = typename FortranTypeHelper<HOST_T>::Type;
222
223template <typename... HT> constexpr inline bool FortranTypeExists() {
224 return (... && (!std::is_same_v<FortranType<HT>, UnknownType>));
225}
226
227} // namespace host
228} // namespace Fortran::evaluate
229
230#endif // FORTRAN_EVALUATE_HOST_H_
231

source code of flang/lib/Evaluate/host.h