llvm/lib/MC/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/MC/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(StringRef 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 = ("invalid target '" + ArchName + "'.\n").str();
  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 = "unable to get target for '" + TheTriple.getTriple() +
  53               "', see --version and --triple.";
  54       return nullptr;
  55     }
  56   }
  57
  58   return TheTarget;
  59 }
  60
  61 const Target *TargetRegistry::lookupTarget(StringRef TT, std::string &Error) {
  62   // Provide special warning when no targets are initialized.
  63   if (targets().begin() == targets().end()) {
  64     Error = "Unable to find target for this triple (no targets are registered)";
  65     return nullptr;
  66   }
  67   Triple::ArchType Arch = Triple(TT).getArch();
  68   auto ArchMatch = [&](const Target &T) { return T.ArchMatchFn(Arch); };
  69   auto I = find_if(targets(), ArchMatch);
  70
  71   if (I == targets().end()) {
  72     Error = ("No available targets are compatible with triple \"" + TT + "\"")
  73                 .str();
  74     return nullptr;
  75   }
  76
  77   auto J = std::find_if(std::next(I), targets().end(), ArchMatch);
  78   if (J != targets().end()) {
  79     Error = std::string("Cannot choose between targets \"") + I->Name +
  80             "\" and \"" + J->Name + "\"";
  81     return nullptr;
  82   }
  83
  84   return &*I;
  85 }
  86
  87 void TargetRegistry::RegisterTarget(Target &T, const char *Name,
  88                                     const char *ShortDesc,
  89                                     const char *BackendName,
  90                                     Target::ArchMatchFnTy ArchMatchFn,
  91                                     bool HasJIT) {
  92   assert(Name && ShortDesc && ArchMatchFn &&
  93          "Missing required target information!");
  94
  95   // Check if this target has already been initialized, we allow this as a
  96   // convenience to some clients.
  97   if (T.Name)
  98     return;
  99
 100   // Add to the list of targets.
 101   T.Next = FirstTarget;
 102   FirstTarget = &T;
 103
 104   T.Name = Name;
 105   T.ShortDesc = ShortDesc;
 106   T.BackendName = BackendName;
 107   T.ArchMatchFn = ArchMatchFn;
 108   T.HasJIT = HasJIT;
 109 }
 110
 111 static int TargetArraySortFn(const std::pair<StringRef, const Target *> *LHS,
 112                              const std::pair<StringRef, const Target *> *RHS) {
 113   return LHS->first.compare(RHS->first);
 114 }
 115
 116 void TargetRegistry::printRegisteredTargetsForVersion(raw_ostream &OS) {
 117   std::vector<std::pair<StringRef, const Target*> > Targets;
 118   size_t Width = 0;
 119   for (const auto &T : TargetRegistry::targets()) {
 120     Targets.push_back(std::make_pair(T.getName(), &T));
 121     Width = std::max(Width, Targets.back().first.size());
 122   }
 123   array_pod_sort(Targets.begin(), Targets.end(), TargetArraySortFn);
 124
 125   OS << "\n";
 126   OS << "  Registered Targets:\n";
 127   for (const auto &Target : Targets) {
 128     OS << "    " << Target.first;
 129     OS.indent(Width - Target.first.size())
 130         << " - " << Target.second->getShortDescription() << '\n';
 131   }
 132   if (Targets.empty())
 133     OS << "    (none)\n";
 134 }