lib/Support/TargetRegistry.cpp

   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>
  16 using namespace llvm;
  17
  18 // Clients are responsible for avoid race conditions in registration.
  19 static Target *FirstTarget = nullptr;
  20
  21 iterator_range<TargetRegistry::iterator> TargetRegistry::targets() {
  22   return make_range(iterator(FirstTarget), iterator());
  23 }
  24
  25 const 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 = find_if(targets(),
  34                      [&](const Target &T) { return ArchName == T.getName(); });
  35
  36     if (I == targets().end()) {
  37       Error = "error: invalid target '" + ArchName + "'.\n";
  38       return nullptr;
  39     }
  40
  41     TheTarget = &*I;
  42
  43     // Adjust the triple to match (if known), otherwise stick with the
  44     // given triple.
  45     Triple::ArchType Type = Triple::getArchTypeForLLVMName(ArchName);
  46     if (Type != Triple::UnknownArch)
  47       TheTriple.setArch(Type);
  48   } else {
  49     // Get the target specific parser.
  50     std::string TempError;
  51     TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), TempError);
  52     if (!TheTarget) {
  53       Error = ": error: unable to get target for '"
  54             + TheTriple.getTriple()
  55             + "', see --version and --triple.\n";
  56       return nullptr;
  57     }
  58   }
  59
  60   return TheTarget;
  61 }
  62
  63 const Target *TargetRegistry::lookupTarget(const std::string &TT,
  64                                            std::string &Error) {
  65   // Provide special warning when no targets are initialized.
  66   if (targets().begin() == targets().end()) {
  67     Error = "Unable to find target for this triple (no targets are registered)";
  68     return nullptr;
  69   }
  70   Triple::ArchType Arch = Triple(TT).getArch();
  71   auto ArchMatch = [&](const Target &T) { return T.ArchMatchFn(Arch); };
  72   auto I = find_if(targets(), ArchMatch);
  73
  74   if (I == targets().end()) {
  75     Error = "No available targets are compatible with triple \"" + TT + "\"";
  76     return nullptr;
  77   }
  78
  79   auto J = std::find_if(std::next(I), targets().end(), ArchMatch);
  80   if (J != targets().end()) {
  81     Error = std::string("Cannot choose between targets \"") + I->Name +
  82             "\" and \"" + J->Name + "\"";
  83     return nullptr;
  84   }
  85
  86   return &*I;
  87 }
  88
  89 void TargetRegistry::RegisterTarget(Target &T, const char *Name,
  90                                     const char *ShortDesc,
  91                                     const char *BackendName,
  92                                     Target::ArchMatchFnTy ArchMatchFn,
  93                                     bool HasJIT) {
  94   assert(Name && ShortDesc && ArchMatchFn &&
  95          "Missing required target information!");
  96
  97   // Check if this target has already been initialized, we allow this as a
  98   // convenience to some clients.
  99   if (T.Name)
 100     return;
 101
 102   // Add to the list of targets.
 103   T.Next = FirstTarget;
 104   FirstTarget = &T;
 105
 106   T.Name = Name;
 107   T.ShortDesc = ShortDesc;
 108   T.BackendName = BackendName;
 109   T.ArchMatchFn = ArchMatchFn;
 110   T.HasJIT = HasJIT;
 111 }
 112
 113 static 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
 118 void TargetRegistry::printRegisteredTargetsForVersion(raw_ostream &OS) {
 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   OS << "  Registered Targets:\n";
 128   for (unsigned i = 0, e = Targets.size(); i != e; ++i) {
 129     OS << "    " << Targets[i].first;
 130     OS.indent(Width - Targets[i].first.size()) << " - "
 131       << Targets[i].second->getShortDescription() << '\n';
 132   }
 133   if (Targets.empty())
 134     OS << "    (none)\n";
 135 }