1//===--- TargetRegistry.cpp - Target registration -------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "llvm/Support/TargetRegistry.h"
11#include "llvm/ADT/STLExtras.h"
12#include "llvm/ADT/StringRef.h"
13#include "llvm/Support/raw_ostream.h"
14#include <cassert>
15#include <vector>
16using namespace llvm;
17
18// Clients are responsible for avoid race conditions in registration.
19static Target *FirstTarget = nullptr;
20
21iterator_range<TargetRegistry::iterator> TargetRegistry::targets() {
22  return make_range(iterator(FirstTarget), iterator());
23}
24
25const Target *TargetRegistry::lookupTarget(const std::string &ArchName,
26                                           Triple &TheTriple,
27                                           std::string &Error) {
28  // Allocate target machine.  First, check whether the user has explicitly
29  // specified an architecture to compile for. If so we have to look it up by
30  // name, because it might be a backend that has no mapping to a target triple.
31  const Target *TheTarget = nullptr;
32  if (!ArchName.empty()) {
33    auto I =
34        std::find_if(targets().begin(), targets().end(),
35                     [&](const Target &T) { return ArchName == T.getName(); });
36
37    if (I == targets().end()) {
38      Error = "error: invalid target '" + ArchName + "'.\n";
39      return nullptr;
40    }
41
42    TheTarget = &*I;
43
44    // Adjust the triple to match (if known), otherwise stick with the
45    // given triple.
46    Triple::ArchType Type = Triple::getArchTypeForLLVMName(ArchName);
47    if (Type != Triple::UnknownArch)
48      TheTriple.setArch(Type);
49  } else {
50    // Get the target specific parser.
51    std::string TempError;
52    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), TempError);
53    if (!TheTarget) {
54      Error = ": error: unable to get target for '"
55            + TheTriple.getTriple()
56            + "', see --version and --triple.\n";
57      return nullptr;
58    }
59  }
60
61  return TheTarget;
62}
63
64const Target *TargetRegistry::lookupTarget(const std::string &TT,
65                                           std::string &Error) {
66  // Provide special warning when no targets are initialized.
67  if (targets().begin() == targets().end()) {
68    Error = "Unable to find target for this triple (no targets are registered)";
69    return nullptr;
70  }
71  Triple::ArchType Arch = Triple(TT).getArch();
72  auto ArchMatch = [&](const Target &T) { return T.ArchMatchFn(Arch); };
73  auto I = std::find_if(targets().begin(), targets().end(), ArchMatch);
74
75  if (I == targets().end()) {
76    Error = "No available targets are compatible with this triple.";
77    return nullptr;
78  }
79
80  auto J = std::find_if(std::next(I), targets().end(), ArchMatch);
81  if (J != targets().end()) {
82    Error = std::string("Cannot choose between targets \"") + I->Name +
83            "\" and \"" + J->Name + "\"";
84    return nullptr;
85  }
86
87  return &*I;
88}
89
90void TargetRegistry::RegisterTarget(Target &T,
91                                    const char *Name,
92                                    const char *ShortDesc,
93                                    Target::ArchMatchFnTy ArchMatchFn,
94                                    bool HasJIT) {
95  assert(Name && ShortDesc && ArchMatchFn &&
96         "Missing required target information!");
97
98  // Check if this target has already been initialized, we allow this as a
99  // convenience to some clients.
100  if (T.Name)
101    return;
102
103  // Add to the list of targets.
104  T.Next = FirstTarget;
105  FirstTarget = &T;
106
107  T.Name = Name;
108  T.ShortDesc = ShortDesc;
109  T.ArchMatchFn = ArchMatchFn;
110  T.HasJIT = HasJIT;
111}
112
113static int TargetArraySortFn(const std::pair<StringRef, const Target *> *LHS,
114                             const std::pair<StringRef, const Target *> *RHS) {
115  return LHS->first.compare(RHS->first);
116}
117
118void TargetRegistry::printRegisteredTargetsForVersion() {
119  std::vector<std::pair<StringRef, const Target*> > Targets;
120  size_t Width = 0;
121  for (const auto &T : TargetRegistry::targets()) {
122    Targets.push_back(std::make_pair(T.getName(), &T));
123    Width = std::max(Width, Targets.back().first.size());
124  }
125  array_pod_sort(Targets.begin(), Targets.end(), TargetArraySortFn);
126
127  raw_ostream &OS = outs();
128  OS << "  Registered Targets:\n";
129  for (unsigned i = 0, e = Targets.size(); i != e; ++i) {
130    OS << "    " << Targets[i].first;
131    OS.indent(Width - Targets[i].first.size()) << " - "
132      << Targets[i].second->getShortDescription() << '\n';
133  }
134  if (Targets.empty())
135    OS << "    (none)\n";
136}
137