1 //===-- TargetSelect.cpp - Target Chooser Code ----------------------------===//
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 // This just asks the TargetRegistry for the appropriate JIT to use, and allows
11 // the user to specify a specific one on the commandline with -march=x. Clients
12 // should initialize targets prior to calling createJIT.
13 //
14 //===----------------------------------------------------------------------===//
15
16 #include "llvm/ExecutionEngine/ExecutionEngine.h"
17 #include "llvm/Module.h"
18 #include "llvm/ADT/Triple.h"
19 #include "llvm/MC/SubtargetFeature.h"
20 #include "llvm/Target/TargetMachine.h"
21 #include "llvm/Support/CommandLine.h"
22 #include "llvm/Support/Host.h"
23 #include "llvm/Support/TargetRegistry.h"
24 #include "llvm/Support/raw_ostream.h"
25 using namespace llvm;
26
27 /// selectTarget - Pick a target either via -march or by guessing the native
28 /// arch. Add any CPU features specified via -mcpu or -mattr.
selectTarget(Module * Mod,StringRef MArch,StringRef MCPU,const SmallVectorImpl<std::string> & MAttrs,Reloc::Model RM,CodeModel::Model CM,std::string * ErrorStr)29 TargetMachine *EngineBuilder::selectTarget(Module *Mod,
30 StringRef MArch,
31 StringRef MCPU,
32 const SmallVectorImpl<std::string>& MAttrs,
33 Reloc::Model RM,
34 CodeModel::Model CM,
35 std::string *ErrorStr) {
36 Triple TheTriple(Mod->getTargetTriple());
37 if (TheTriple.getTriple().empty())
38 TheTriple.setTriple(sys::getHostTriple());
39
40 // Adjust the triple to match what the user requested.
41 const Target *TheTarget = 0;
42 if (!MArch.empty()) {
43 for (TargetRegistry::iterator it = TargetRegistry::begin(),
44 ie = TargetRegistry::end(); it != ie; ++it) {
45 if (MArch == it->getName()) {
46 TheTarget = &*it;
47 break;
48 }
49 }
50
51 if (!TheTarget) {
52 *ErrorStr = "No available targets are compatible with this -march, "
53 "see -version for the available targets.\n";
54 return 0;
55 }
56
57 // Adjust the triple to match (if known), otherwise stick with the
58 // module/host triple.
59 Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
60 if (Type != Triple::UnknownArch)
61 TheTriple.setArch(Type);
62 } else {
63 std::string Error;
64 TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error);
65 if (TheTarget == 0) {
66 if (ErrorStr)
67 *ErrorStr = Error;
68 return 0;
69 }
70 }
71
72 if (!TheTarget->hasJIT()) {
73 errs() << "WARNING: This target JIT is not designed for the host you are"
74 << " running. If bad things happen, please choose a different "
75 << "-march switch.\n";
76 }
77
78 // Package up features to be passed to target/subtarget
79 std::string FeaturesStr;
80 if (!MAttrs.empty()) {
81 SubtargetFeatures Features;
82 for (unsigned i = 0; i != MAttrs.size(); ++i)
83 Features.AddFeature(MAttrs[i]);
84 FeaturesStr = Features.getString();
85 }
86
87 // Allocate a target...
88 TargetMachine *Target = TheTarget->createTargetMachine(TheTriple.getTriple(),
89 MCPU, FeaturesStr,
90 RM, CM);
91 assert(Target && "Could not allocate target machine!");
92 return Target;
93 }
94