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 }
136