lib/Support/TargetRegistry.cpp

   1 //===--- TargetRegistry.cpp - Target registration -------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/Support/TargetRegistry.h"
  10 #include "llvm/ADT/STLExtras.h"
  11 #include "llvm/ADT/StringRef.h"
  12 #include "llvm/Support/raw_ostream.h"
  13 #include <cassert>
  14 #include <vector>
  15 using namespace llvm;
  16
  17 // Clients are responsible for avoid race conditions in registration.
  18 static Target *FirstTarget = nullptr;
  19
  20 iterator_range<TargetRegistry::iterator> TargetRegistry::targets() {
  21   return make_range(iterator(FirstTarget), iterator());
  22 }
  23
  24 const Target *TargetRegistry::lookupTarget(const std::string &ArchName,
  25                                            Triple &TheTriple,
  26                                            std::string &Error) {
  27   // Allocate target machine.  First, check whether the user has explicitly
  28   // specified an architecture to compile for. If so we have to look it up by
  29   // name, because it might be a backend that has no mapping to a target triple.
  30   const Target *TheTarget = nullptr;
  31   if (!ArchName.empty()) {
  32     auto I = find_if(targets(),
  33                      [&](const Target &T) { return ArchName == T.getName(); });
  34
  35     if (I == targets().end()) {
  36       Error = "error: invalid target '" + ArchName + "'.\n";
  37       return nullptr;
  38     }
  39
  40     TheTarget = &*I;
  41
  42     // Adjust the triple to match (if known), otherwise stick with the
  43     // given triple.
  44     Triple::ArchType Type = Triple::getArchTypeForLLVMName(ArchName);
  45     if (Type != Triple::UnknownArch)
  46       TheTriple.setArch(Type);
  47   } else {
  48     // Get the target specific parser.
  49     std::string TempError;
  50     TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), TempError);
  51     if (!TheTarget) {
  52       Error = ": error: unable to get target for '"
  53             + TheTriple.getTriple()
  54             + "', see --version and --triple.\n";
  55       return nullptr;
  56     }
  57   }
  58
  59   return TheTarget;
  60 }
  61
  62 const Target *TargetRegistry::lookupTarget(const std::string &TT,
  63                                            std::string &Error) {
  64   // Provide special warning when no targets are initialized.
  65   if (targets().begin() == targets().end()) {
  66     Error = "Unable to find target for this triple (no targets are registered)";
  67     return nullptr;
  68   }
  69   Triple::ArchType Arch = Triple(TT).getArch();
  70   auto ArchMatch = [&](const Target &T) { return T.ArchMatchFn(Arch); };
  71   auto I = find_if(targets(), ArchMatch);
  72
  73   if (I == targets().end()) {
  74     Error = "No available targets are compatible with triple \"" + TT + "\"";
  75     return nullptr;
  76   }
  77
  78   auto J = std::find_if(std::next(I), targets().end(), ArchMatch);
  79   if (J != targets().end()) {
  80     Error = std::string("Cannot choose between targets \"") + I->Name +
  81             "\" and \"" + J->Name + "\"";
  82     return nullptr;
  83   }
  84
  85   return &*I;
  86 }
  87
  88 void TargetRegistry::RegisterTarget(Target &T, const char *Name,
  89                                     const char *ShortDesc,
  90                                     const char *BackendName,
  91                                     Target::ArchMatchFnTy ArchMatchFn,
  92                                     bool HasJIT) {
  93   assert(Name && ShortDesc && ArchMatchFn &&
  94          "Missing required target information!");
  95
  96   // Check if this target has already been initialized, we allow this as a
  97   // convenience to some clients.
  98   if (T.Name)
  99     return;
 100
 101   // Add to the list of targets.
 102   T.Next = FirstTarget;
 103   FirstTarget = &T;
 104
 105   T.Name = Name;
 106   T.ShortDesc = ShortDesc;
 107   T.BackendName = BackendName;
 108   T.ArchMatchFn = ArchMatchFn;
 109   T.HasJIT = HasJIT;
 110 }
 111
 112 static int TargetArraySortFn(const std::pair<StringRef, const Target *> *LHS,
 113                              const std::pair<StringRef, const Target *> *RHS) {
 114   return LHS->first.compare(RHS->first);
 115 }
 116
 117 void TargetRegistry::printRegisteredTargetsForVersion(raw_ostream &OS) {
 118   std::vector<std::pair<StringRef, const Target*> > Targets;
 119   size_t Width = 0;
 120   for (const auto &T : TargetRegistry::targets()) {
 121     Targets.push_back(std::make_pair(T.getName(), &T));
 122     Width = std::max(Width, Targets.back().first.size());
 123   }
 124   array_pod_sort(Targets.begin(), Targets.end(), TargetArraySortFn);
 125
 126   OS << "  Registered Targets:\n";
 127   for (unsigned i = 0, e = Targets.size(); i != e; ++i) {
 128     OS << "    " << Targets[i].first;
 129     OS.indent(Width - Targets[i].first.size()) << " - "
 130       << Targets[i].second->getShortDescription() << '\n';
 131   }
 132   if (Targets.empty())
 133     OS << "    (none)\n";
 134 }