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
21TargetRegistry::iterator TargetRegistry::begin() {
22  return iterator(FirstTarget);
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    for (TargetRegistry::iterator it = TargetRegistry::begin(),
34           ie = TargetRegistry::end(); it != ie; ++it) {
35      if (ArchName == it->getName()) {
36        TheTarget = &*it;
37        break;
38      }
39    }
40
41    if (!TheTarget) {
42      Error = "error: invalid target '" + ArchName + "'.\n";
43      return nullptr;
44    }
45
46    // Adjust the triple to match (if known), otherwise stick with the
47    // given triple.
48    Triple::ArchType Type = Triple::getArchTypeForLLVMName(ArchName);
49    if (Type != Triple::UnknownArch)
50      TheTriple.setArch(Type);
51  } else {
52    // Get the target specific parser.
53    std::string TempError;
54    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), TempError);
55    if (!TheTarget) {
56      Error = ": error: unable to get target for '"
57            + TheTriple.getTriple()
58            + "', see --version and --triple.\n";
59      return nullptr;
60    }
61  }
62
63  return TheTarget;
64}
65
66const Target *TargetRegistry::lookupTarget(const std::string &TT,
67                                           std::string &Error) {
68  // Provide special warning when no targets are initialized.
69  if (begin() == end()) {
70    Error = "Unable to find target for this triple (no targets are registered)";
71    return nullptr;
72  }
73  const Target *Matching = nullptr;
74  Triple::ArchType Arch =  Triple(TT).getArch();
75  for (iterator it = begin(), ie = end(); it != ie; ++it) {
76    if (it->ArchMatchFn(Arch)) {
77      if (Matching) {
78        Error = std::string("Cannot choose between targets \"") +
79          Matching->Name  + "\" and \"" + it->Name + "\"";
80        return nullptr;
81      }
82      Matching = &*it;
83    }
84  }
85
86  if (!Matching) {
87    Error = "No available targets are compatible with this triple, "
88      "see -version for the available targets.";
89    return nullptr;
90  }
91
92  return Matching;
93}
94
95void TargetRegistry::RegisterTarget(Target &T,
96                                    const char *Name,
97                                    const char *ShortDesc,
98                                    Target::ArchMatchFnTy ArchMatchFn,
99                                    bool HasJIT) {
100  assert(Name && ShortDesc && ArchMatchFn &&
101         "Missing required target information!");
102
103  // Check if this target has already been initialized, we allow this as a
104  // convenience to some clients.
105  if (T.Name)
106    return;
107
108  // Add to the list of targets.
109  T.Next = FirstTarget;
110  FirstTarget = &T;
111
112  T.Name = Name;
113  T.ShortDesc = ShortDesc;
114  T.ArchMatchFn = ArchMatchFn;
115  T.HasJIT = HasJIT;
116}
117
118static int TargetArraySortFn(const std::pair<StringRef, const Target *> *LHS,
119                             const std::pair<StringRef, const Target *> *RHS) {
120  return LHS->first.compare(RHS->first);
121}
122
123void TargetRegistry::printRegisteredTargetsForVersion() {
124  std::vector<std::pair<StringRef, const Target*> > Targets;
125  size_t Width = 0;
126  for (TargetRegistry::iterator I = TargetRegistry::begin(),
127       E = TargetRegistry::end();
128       I != E; ++I) {
129    Targets.push_back(std::make_pair(I->getName(), &*I));
130    Width = std::max(Width, Targets.back().first.size());
131  }
132  array_pod_sort(Targets.begin(), Targets.end(), TargetArraySortFn);
133
134  raw_ostream &OS = outs();
135  OS << "  Registered Targets:\n";
136  for (unsigned i = 0, e = Targets.size(); i != e; ++i) {
137    OS << "    " << Targets[i].first;
138    OS.indent(Width - Targets[i].first.size()) << " - "
139      << Targets[i].second->getShortDescription() << '\n';
140  }
141  if (Targets.empty())
142    OS << "    (none)\n";
143}
144