llvm-6502/lib/ExecutionEngine/TargetSelect.cpp
2011-11-01 21:32:20 +00:00

94 lines
3.3 KiB
C++

//===-- TargetSelect.cpp - Target Chooser Code ----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This just asks the TargetRegistry for the appropriate JIT to use, and allows
// the user to specify a specific one on the commandline with -march=x. Clients
// should initialize targets prior to calling createJIT.
//
//===----------------------------------------------------------------------===//
#include "llvm/ExecutionEngine/ExecutionEngine.h"
#include "llvm/Module.h"
#include "llvm/ADT/Triple.h"
#include "llvm/MC/SubtargetFeature.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
/// selectTarget - Pick a target either via -march or by guessing the native
/// arch. Add any CPU features specified via -mcpu or -mattr.
TargetMachine *EngineBuilder::selectTarget(Module *Mod,
StringRef MArch,
StringRef MCPU,
const SmallVectorImpl<std::string>& MAttrs,
Reloc::Model RM,
CodeModel::Model CM,
std::string *ErrorStr) {
Triple TheTriple(Mod->getTargetTriple());
if (TheTriple.getTriple().empty())
TheTriple.setTriple(sys::getDefaultTargetTriple());
// Adjust the triple to match what the user requested.
const Target *TheTarget = 0;
if (!MArch.empty()) {
for (TargetRegistry::iterator it = TargetRegistry::begin(),
ie = TargetRegistry::end(); it != ie; ++it) {
if (MArch == it->getName()) {
TheTarget = &*it;
break;
}
}
if (!TheTarget) {
*ErrorStr = "No available targets are compatible with this -march, "
"see -version for the available targets.\n";
return 0;
}
// Adjust the triple to match (if known), otherwise stick with the
// module/host triple.
Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);
if (Type != Triple::UnknownArch)
TheTriple.setArch(Type);
} else {
std::string Error;
TheTarget = TargetRegistry::lookupTarget(TheTriple.getTriple(), Error);
if (TheTarget == 0) {
if (ErrorStr)
*ErrorStr = Error;
return 0;
}
}
if (!TheTarget->hasJIT()) {
errs() << "WARNING: This target JIT is not designed for the host you are"
<< " running. If bad things happen, please choose a different "
<< "-march switch.\n";
}
// Package up features to be passed to target/subtarget
std::string FeaturesStr;
if (!MAttrs.empty()) {
SubtargetFeatures Features;
for (unsigned i = 0; i != MAttrs.size(); ++i)
Features.AddFeature(MAttrs[i]);
FeaturesStr = Features.getString();
}
// Allocate a target...
TargetMachine *Target = TheTarget->createTargetMachine(TheTriple.getTriple(),
MCPU, FeaturesStr,
RM, CM);
assert(Target && "Could not allocate target machine!");
return Target;
}