xref: /llvm-project/flang/runtime/misc-intrinsic.cpp (revision d06b55e7934635049d55efff2dc9e745f911240c)
1 //===-- runtime/misc-intrinsic.cpp ----------------------------------------===//
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 #include "flang/Runtime/misc-intrinsic.h"
10 #include "terminator.h"
11 #include "tools.h"
12 #include "flang/Common/optional.h"
13 #include "flang/Runtime/descriptor.h"
14 #include <algorithm>
15 #include <cstdio>
16 #include <cstring>
17 
18 namespace Fortran::runtime {
19 
20 static RT_API_ATTRS void TransferImpl(Descriptor &result,
21     const Descriptor &source, const Descriptor &mold, const char *sourceFile,
22     int line, Fortran::common::optional<std::int64_t> resultExtent) {
23   int rank{resultExtent.has_value() ? 1 : 0};
24   std::size_t elementBytes{mold.ElementBytes()};
25   result.Establish(mold.type(), elementBytes, nullptr, rank, nullptr,
26       CFI_attribute_allocatable, mold.Addendum() != nullptr);
27   if (resultExtent) {
28     result.GetDimension(0).SetBounds(1, *resultExtent);
29   }
30   if (const DescriptorAddendum * addendum{mold.Addendum()}) {
31     *result.Addendum() = *addendum;
32   }
33   if (int stat{result.Allocate()}) {
34     Terminator{sourceFile, line}.Crash(
35         "TRANSFER: could not allocate memory for result; STAT=%d", stat);
36   }
37   char *to{result.OffsetElement<char>()};
38   std::size_t resultBytes{result.Elements() * result.ElementBytes()};
39   const std::size_t sourceElementBytes{source.ElementBytes()};
40   std::size_t sourceElements{source.Elements()};
41   SubscriptValue sourceAt[maxRank];
42   source.GetLowerBounds(sourceAt);
43   while (resultBytes > 0 && sourceElements > 0) {
44     std::size_t toMove{std::min(resultBytes, sourceElementBytes)};
45     std::memcpy(to, source.Element<char>(sourceAt), toMove);
46     to += toMove;
47     resultBytes -= toMove;
48     --sourceElements;
49     source.IncrementSubscripts(sourceAt);
50   }
51   if (resultBytes > 0) {
52     std::memset(to, 0, resultBytes);
53   }
54 }
55 
56 extern "C" {
57 RT_EXT_API_GROUP_BEGIN
58 
59 void RTDEF(Rename)(const Descriptor &path1, const Descriptor &path2,
60     const Descriptor *status, const char *sourceFile, int line) {
61   Terminator terminator{sourceFile, line};
62 #if !defined(RT_DEVICE_COMPILATION)
63   char *pathSrc{EnsureNullTerminated(
64       path1.OffsetElement(), path1.ElementBytes(), terminator)};
65   char *pathDst{EnsureNullTerminated(
66       path2.OffsetElement(), path2.ElementBytes(), terminator)};
67 
68   // We simply call rename(2) from POSIX
69   int result{rename(pathSrc, pathDst)};
70   if (status) {
71     // When an error has happened,
72     int errorCode{0}; // Assume success
73     if (result != 0) {
74       // The rename operation has failed, so return the error code as status.
75       errorCode = errno;
76     }
77     StoreIntToDescriptor(status, errorCode, terminator);
78   }
79 
80   // Deallocate memory if EnsureNullTerminated dynamically allocated memory
81   if (pathSrc != path1.OffsetElement()) {
82     FreeMemory(pathSrc);
83   }
84   if (pathDst != path2.OffsetElement()) {
85     FreeMemory(pathDst);
86   }
87 #else // !defined(RT_DEVICE_COMPILATION)
88   terminator.Crash("RENAME intrinsic is only supported on host devices");
89 #endif // !defined(RT_DEVICE_COMPILATION)
90 }
91 
92 void RTDEF(Transfer)(Descriptor &result, const Descriptor &source,
93     const Descriptor &mold, const char *sourceFile, int line) {
94   Fortran::common::optional<std::int64_t> elements;
95   if (mold.rank() > 0) {
96     if (std::size_t sourceElementBytes{
97             source.Elements() * source.ElementBytes()}) {
98       if (std::size_t moldElementBytes{mold.ElementBytes()}) {
99         elements = static_cast<std::int64_t>(
100             (sourceElementBytes + moldElementBytes - 1) / moldElementBytes);
101       } else {
102         Terminator{sourceFile, line}.Crash("TRANSFER: zero-sized type of MOLD= "
103                                            "when SOURCE= is not zero-sized");
104       }
105     } else {
106       elements = std::int64_t{0};
107     }
108   }
109   return TransferImpl(
110       result, source, mold, sourceFile, line, std::move(elements));
111 }
112 
113 void RTDEF(TransferSize)(Descriptor &result, const Descriptor &source,
114     const Descriptor &mold, const char *sourceFile, int line,
115     std::int64_t size) {
116   return TransferImpl(result, source, mold, sourceFile, line, size);
117 }
118 
119 RT_EXT_API_GROUP_END
120 } // extern "C"
121 } // namespace Fortran::runtime
122