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/Host.h"
14#include "llvm/Support/raw_ostream.h"
15#include <cassert>
16#include <vector>
17using namespace llvm;
18
19// Clients are responsible for avoid race conditions in registration.
20static Target *FirstTarget = 0;
21
22TargetRegistry::iterator TargetRegistry::begin() {
23  return iterator(FirstTarget);
24}
25
26const Target *TargetRegistry::lookupTarget(const std::string &TT,
27                                           std::string &Error) {
28  // Provide special warning when no targets are initialized.
29  if (begin() == end()) {
30    Error = "Unable to find target for this triple (no targets are registered)";
31    return 0;
32  }
33  const Target *Best = 0, *EquallyBest = 0;
34  unsigned BestQuality = 0;
35  for (iterator it = begin(), ie = end(); it != ie; ++it) {
36    if (unsigned Qual = it->TripleMatchQualityFn(TT)) {
37      if (!Best || Qual > BestQuality) {
38        Best = &*it;
39        EquallyBest = 0;
40        BestQuality = Qual;
41      } else if (Qual == BestQuality)
42        EquallyBest = &*it;
43    }
44  }
45
46  if (!Best) {
47    Error = "No available targets are compatible with this triple, "
48      "see -version for the available targets.";
49    return 0;
50  }
51
52  // Otherwise, take the best target, but make sure we don't have two equally
53  // good best targets.
54  if (EquallyBest) {
55    Error = std::string("Cannot choose between targets \"") +
56      Best->Name  + "\" and \"" + EquallyBest->Name + "\"";
57    return 0;
58  }
59
60  return Best;
61}
62
63void TargetRegistry::RegisterTarget(Target &T,
64                                    const char *Name,
65                                    const char *ShortDesc,
66                                    Target::TripleMatchQualityFnTy TQualityFn,
67                                    bool HasJIT) {
68  assert(Name && ShortDesc && TQualityFn &&
69         "Missing required target information!");
70
71  // Check if this target has already been initialized, we allow this as a
72  // convenience to some clients.
73  if (T.Name)
74    return;
75
76  // Add to the list of targets.
77  T.Next = FirstTarget;
78  FirstTarget = &T;
79
80  T.Name = Name;
81  T.ShortDesc = ShortDesc;
82  T.TripleMatchQualityFn = TQualityFn;
83  T.HasJIT = HasJIT;
84}
85
86const Target *TargetRegistry::getClosestTargetForJIT(std::string &Error) {
87  const Target *TheTarget = lookupTarget(sys::getHostTriple(), Error);
88
89  if (TheTarget && !TheTarget->hasJIT()) {
90    Error = "No JIT compatible target available for this host";
91    return 0;
92  }
93
94  return TheTarget;
95}
96
97static int TargetArraySortFn(const void *LHS, const void *RHS) {
98  typedef std::pair<StringRef, const Target*> pair_ty;
99  return ((const pair_ty*)LHS)->first.compare(((const pair_ty*)RHS)->first);
100}
101
102void TargetRegistry::printRegisteredTargetsForVersion() {
103  std::vector<std::pair<StringRef, const Target*> > Targets;
104  size_t Width = 0;
105  for (TargetRegistry::iterator I = TargetRegistry::begin(),
106       E = TargetRegistry::end();
107       I != E; ++I) {
108    Targets.push_back(std::make_pair(I->getName(), &*I));
109    Width = std::max(Width, Targets.back().first.size());
110  }
111  array_pod_sort(Targets.begin(), Targets.end(), TargetArraySortFn);
112
113  raw_ostream &OS = outs();
114  OS << "  Registered Targets:\n";
115  for (unsigned i = 0, e = Targets.size(); i != e; ++i) {
116    OS << "    " << Targets[i].first;
117    OS.indent(Width - Targets[i].first.size()) << " - "
118      << Targets[i].second->getShortDescription() << '\n';
119  }
120  if (Targets.empty())
121    OS << "    (none)\n";
122}
123