1//===--- TargetRegistry.cpp - Target registration -------------------------===//
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 "llvm/MC/TargetRegistry.h"
10#include "llvm/ADT/STLExtras.h"
11#include "llvm/ADT/StringRef.h"
12#include "llvm/Support/raw_ostream.h"
13#include <cassert>
14#include <vector>
15using namespace llvm;
16
17// Clients are responsible for avoid race conditions in registration.
18static Target *FirstTarget = nullptr;
19
20iterator_range<TargetRegistry::iterator> TargetRegistry::targets() {
21  return make_range(iterator(FirstTarget), iterator());
22}
23
24const Target *TargetRegistry::lookupTarget(StringRef ArchName,
25                                           Triple &TheTriple,
26                                           std::string &Error) {
27  // Allocate target machine.  First, check whether the user has explicitly
28  // specified an architecture to compile for. If so we have to look it up by
29  // name, because it might be a backend that has no mapping to a target triple.
30  const Target *TheTarget = nullptr;
31  if (!ArchName.empty()) {
32    auto I = find_if(targets(),
33                     [&](const Target &T) { return ArchName == T.getName(); });
34
35    if (I == targets().end()) {
36      Error = ("invalid target '" + ArchName + "'.\n").str();
37      return nullptr;
38    }
39
40    TheTarget = &*I;
41
42    // Adjust the triple to match (if known), otherwise stick with the
43    // given triple.
44    Triple::ArchType Type = Triple::getArchTypeForLLVMName(ArchName);
45    if (Type != Triple::UnknownArch)
46      TheTriple.setArch(Type);
47  } else {
48    // Get the target specific parser.
49    std::string TempError;
50    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), TempError);
51    if (!TheTarget) {
52      Error = "unable to get target for '" + TheTriple.getTriple() +
53              "', see --version and --triple.";
54      return nullptr;
55    }
56  }
57
58  return TheTarget;
59}
60
61const Target *TargetRegistry::lookupTarget(StringRef TT, std::string &Error) {
62  // Provide special warning when no targets are initialized.
63  if (targets().begin() == targets().end()) {
64    Error = "Unable to find target for this triple (no targets are registered)";
65    return nullptr;
66  }
67  Triple::ArchType Arch = Triple(TT).getArch();
68  auto ArchMatch = [&](const Target &T) { return T.ArchMatchFn(Arch); };
69  auto I = find_if(targets(), ArchMatch);
70
71  if (I == targets().end()) {
72    Error = ("No available targets are compatible with triple \"" + TT + "\"")
73                .str();
74    return nullptr;
75  }
76
77  auto J = std::find_if(std::next(I), targets().end(), ArchMatch);
78  if (J != targets().end()) {
79    Error = std::string("Cannot choose between targets \"") + I->Name +
80            "\" and \"" + J->Name + "\"";
81    return nullptr;
82  }
83
84  return &*I;
85}
86
87void TargetRegistry::RegisterTarget(Target &T, const char *Name,
88                                    const char *ShortDesc,
89                                    const char *BackendName,
90                                    Target::ArchMatchFnTy ArchMatchFn,
91                                    bool HasJIT) {
92  assert(Name && ShortDesc && ArchMatchFn &&
93         "Missing required target information!");
94
95  // Check if this target has already been initialized, we allow this as a
96  // convenience to some clients.
97  if (T.Name)
98    return;
99
100  // Add to the list of targets.
101  T.Next = FirstTarget;
102  FirstTarget = &T;
103
104  T.Name = Name;
105  T.ShortDesc = ShortDesc;
106  T.BackendName = BackendName;
107  T.ArchMatchFn = ArchMatchFn;
108  T.HasJIT = HasJIT;
109}
110
111static int TargetArraySortFn(const std::pair<StringRef, const Target *> *LHS,
112                             const std::pair<StringRef, const Target *> *RHS) {
113  return LHS->first.compare(RHS->first);
114}
115
116void TargetRegistry::printRegisteredTargetsForVersion(raw_ostream &OS) {
117  std::vector<std::pair<StringRef, const Target*> > Targets;
118  size_t Width = 0;
119  for (const auto &T : TargetRegistry::targets()) {
120    Targets.push_back(std::make_pair(T.getName(), &T));
121    Width = std::max(Width, Targets.back().first.size());
122  }
123  array_pod_sort(Targets.begin(), Targets.end(), TargetArraySortFn);
124
125  OS << "\n";
126  OS << "  Registered Targets:\n";
127  for (const auto &Target : Targets) {
128    OS << "    " << Target.first;
129    OS.indent(Width - Target.first.size())
130        << " - " << Target.second->getShortDescription() << '\n';
131  }
132  if (Targets.empty())
133    OS << "    (none)\n";
134}
135