source: icGREP/icgrep-devel/llvm-3.8.0.src/lib/ExecutionEngine/TargetSelect.cpp @ 5667

Last change on this file since 5667 was 5027, checked in by cameron, 3 years ago

Upgrade to llvm 3.8

File size: 3.7 KB
Line 
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 target to use, and
11// allows the user to specify a specific one on the commandline with -march=x,
12// -mcpu=y, and -mattr=a,-b,+c. Clients should initialize targets prior to
13// calling selectTarget().
14//
15//===----------------------------------------------------------------------===//
16
17#include "llvm/ExecutionEngine/ExecutionEngine.h"
18#include "llvm/ADT/Triple.h"
19#include "llvm/IR/Module.h"
20#include "llvm/MC/SubtargetFeature.h"
21#include "llvm/Support/CommandLine.h"
22#include "llvm/Support/Host.h"
23#include "llvm/Support/TargetRegistry.h"
24#include "llvm/Target/TargetMachine.h"
25
26using namespace llvm;
27
28TargetMachine *EngineBuilder::selectTarget() {
29  Triple TT;
30
31  // MCJIT can generate code for remote targets, but the old JIT and Interpreter
32  // must use the host architecture.
33  if (WhichEngine != EngineKind::Interpreter && M)
34    TT.setTriple(M->getTargetTriple());
35
36  return selectTarget(TT, MArch, MCPU, MAttrs);
37}
38
39/// selectTarget - Pick a target either via -march or by guessing the native
40/// arch.  Add any CPU features specified via -mcpu or -mattr.
41TargetMachine *EngineBuilder::selectTarget(const Triple &TargetTriple,
42                              StringRef MArch,
43                              StringRef MCPU,
44                              const SmallVectorImpl<std::string>& MAttrs) {
45  Triple TheTriple(TargetTriple);
46  if (TheTriple.getTriple().empty())
47    TheTriple.setTriple(sys::getProcessTriple());
48
49  // Adjust the triple to match what the user requested.
50  const Target *TheTarget = nullptr;
51  if (!MArch.empty()) {
52    auto I = std::find_if(
53        TargetRegistry::targets().begin(), TargetRegistry::targets().end(),
54        [&](const Target &T) { return MArch == T.getName(); });
55
56    if (I == TargetRegistry::targets().end()) {
57      if (ErrorStr)
58        *ErrorStr = "No available targets are compatible with this -march, "
59                    "see -version for the available targets.\n";
60      return nullptr;
61    }
62
63    TheTarget = &*I;
64
65    // Adjust the triple to match (if known), otherwise stick with the
66    // requested/host triple.
67    Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
68    if (Type != Triple::UnknownArch)
69      TheTriple.setArch(Type);
70  } else {
71    std::string Error;
72    TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error);
73    if (!TheTarget) {
74      if (ErrorStr)
75        *ErrorStr = Error;
76      return nullptr;
77    }
78  }
79
80  // Package up features to be passed to target/subtarget
81  std::string FeaturesStr;
82  if (!MAttrs.empty()) {
83    SubtargetFeatures Features;
84    for (unsigned i = 0; i != MAttrs.size(); ++i)
85      Features.AddFeature(MAttrs[i]);
86    FeaturesStr = Features.getString();
87  }
88
89  // FIXME: non-iOS ARM FastISel is broken with MCJIT.
90  if (TheTriple.getArch() == Triple::arm &&
91      !TheTriple.isiOS() &&
92      OptLevel == CodeGenOpt::None) {
93    OptLevel = CodeGenOpt::Less;
94  }
95
96  // Allocate a target...
97  TargetMachine *Target = TheTarget->createTargetMachine(TheTriple.getTriple(),
98                                                         MCPU, FeaturesStr,
99                                                         Options,
100                                                         RelocModel, CMModel,
101                                                         OptLevel);
102  assert(Target && "Could not allocate target machine!");
103  return Target;
104}
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