TargetRegistry.cpp revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
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 = nullptr;
21
22TargetRegistry::iterator TargetRegistry::begin() {
23  return iterator(FirstTarget);
24}
25
26const Target *TargetRegistry::lookupTarget(const std::string &ArchName,
27                                           Triple &TheTriple,
28                                           std::string &Error) {
29  // Allocate target machine.  First, check whether the user has explicitly
30  // specified an architecture to compile for. If so we have to look it up by
31  // name, because it might be a backend that has no mapping to a target triple.
32  const Target *TheTarget = nullptr;
33  if (!ArchName.empty()) {
34    for (TargetRegistry::iterator it = TargetRegistry::begin(),
35           ie = TargetRegistry::end(); it != ie; ++it) {
36      if (ArchName == it->getName()) {
37        TheTarget = &*it;
38        break;
39      }
40    }
41
42    if (!TheTarget) {
43      Error = "error: invalid target '" + ArchName + "'.\n";
44      return nullptr;
45    }
46
47    // Adjust the triple to match (if known), otherwise stick with the
48    // given triple.
49    Triple::ArchType Type = Triple::getArchTypeForLLVMName(ArchName);
50    if (Type != Triple::UnknownArch)
51      TheTriple.setArch(Type);
52  } else {
53    // Get the target specific parser.
54    std::string TempError;
55    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), TempError);
56    if (!TheTarget) {
57      Error = ": error: unable to get target for '"
58            + TheTriple.getTriple()
59            + "', see --version and --triple.\n";
60      return nullptr;
61    }
62  }
63
64  return TheTarget;
65}
66
67const Target *TargetRegistry::lookupTarget(const std::string &TT,
68                                           std::string &Error) {
69  // Provide special warning when no targets are initialized.
70  if (begin() == end()) {
71    Error = "Unable to find target for this triple (no targets are registered)";
72    return nullptr;
73  }
74  const Target *Matching = nullptr;
75  Triple::ArchType Arch =  Triple(TT).getArch();
76  for (iterator it = begin(), ie = end(); it != ie; ++it) {
77    if (it->ArchMatchFn(Arch)) {
78      if (Matching) {
79        Error = std::string("Cannot choose between targets \"") +
80          Matching->Name  + "\" and \"" + it->Name + "\"";
81        return nullptr;
82      }
83      Matching = &*it;
84    }
85  }
86
87  if (!Matching) {
88    Error = "No available targets are compatible with this triple, "
89      "see -version for the available targets.";
90    return nullptr;
91  }
92
93  return Matching;
94}
95
96void TargetRegistry::RegisterTarget(Target &T,
97                                    const char *Name,
98                                    const char *ShortDesc,
99                                    Target::ArchMatchFnTy ArchMatchFn,
100                                    bool HasJIT) {
101  assert(Name && ShortDesc && ArchMatchFn &&
102         "Missing required target information!");
103
104  // Check if this target has already been initialized, we allow this as a
105  // convenience to some clients.
106  if (T.Name)
107    return;
108
109  // Add to the list of targets.
110  T.Next = FirstTarget;
111  FirstTarget = &T;
112
113  T.Name = Name;
114  T.ShortDesc = ShortDesc;
115  T.ArchMatchFn = ArchMatchFn;
116  T.HasJIT = HasJIT;
117}
118
119const Target *TargetRegistry::getClosestTargetForJIT(std::string &Error) {
120  const Target *TheTarget = lookupTarget(sys::getDefaultTargetTriple(), Error);
121
122  if (TheTarget && !TheTarget->hasJIT()) {
123    Error = "No JIT compatible target available for this host";
124    return nullptr;
125  }
126
127  return TheTarget;
128}
129
130static int TargetArraySortFn(const std::pair<StringRef, const Target *> *LHS,
131                             const std::pair<StringRef, const Target *> *RHS) {
132  return LHS->first.compare(RHS->first);
133}
134
135void TargetRegistry::printRegisteredTargetsForVersion() {
136  std::vector<std::pair<StringRef, const Target*> > Targets;
137  size_t Width = 0;
138  for (TargetRegistry::iterator I = TargetRegistry::begin(),
139       E = TargetRegistry::end();
140       I != E; ++I) {
141    Targets.push_back(std::make_pair(I->getName(), &*I));
142    Width = std::max(Width, Targets.back().first.size());
143  }
144  array_pod_sort(Targets.begin(), Targets.end(), TargetArraySortFn);
145
146  raw_ostream &OS = outs();
147  OS << "  Registered Targets:\n";
148  for (unsigned i = 0, e = Targets.size(); i != e; ++i) {
149    OS << "    " << Targets[i].first;
150    OS.indent(Width - Targets[i].first.size()) << " - "
151      << Targets[i].second->getShortDescription() << '\n';
152  }
153  if (Targets.empty())
154    OS << "    (none)\n";
155}
156