llvm-6502/lib/ExecutionEngine/JIT/TargetSelect.cpp
2007-10-17 21:28:48 +00:00

80 lines
2.7 KiB
C++

//===-- TargetSelect.cpp - Target Chooser Code ----------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This just asks the TargetMachineRegistry for the appropriate JIT to use, and
// allows the user to specify a specific one on the commandline with -march=x.
//
//===----------------------------------------------------------------------===//
#include "JIT.h"
#include "llvm/Module.h"
#include "llvm/ModuleProvider.h"
#include "llvm/Target/SubtargetFeature.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetMachineRegistry.h"
using namespace llvm;
static cl::opt<const TargetMachineRegistry::entry*, false,
TargetMachineRegistry::Parser>
MArch("march", cl::desc("Architecture to generate assembly for:"));
static cl::opt<std::string>
MCPU("mcpu",
cl::desc("Target a specific cpu type (-mcpu=help for details)"),
cl::value_desc("cpu-name"),
cl::init(""));
static cl::list<std::string>
MAttrs("mattr",
cl::CommaSeparated,
cl::desc("Target specific attributes (-mattr=help for details)"),
cl::value_desc("a1,+a2,-a3,..."));
/// create - Create an return a new JIT compiler if there is one available
/// for the current target. Otherwise, return null.
///
ExecutionEngine *JIT::create(ModuleProvider *MP, std::string *ErrorStr) {
const TargetMachineRegistry::entry *TheArch = MArch;
if (TheArch == 0) {
std::string Error;
TheArch = TargetMachineRegistry::getClosestTargetForJIT(Error);
if (TheArch == 0) {
if (ErrorStr)
*ErrorStr = Error;
return 0;
}
} else if (TheArch->JITMatchQualityFn() == 0) {
cerr << "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 (MCPU.size() || MAttrs.size()) {
SubtargetFeatures Features;
Features.setCPU(MCPU);
for (unsigned i = 0; i != MAttrs.size(); ++i)
Features.AddFeature(MAttrs[i]);
FeaturesStr = Features.getString();
}
// Allocate a target...
TargetMachine *Target = TheArch->CtorFn(*MP->getModule(), FeaturesStr);
assert(Target && "Could not allocate target machine!");
// If the target supports JIT code generation, return a new JIT now.
if (TargetJITInfo *TJ = Target->getJITInfo())
return new JIT(MP, *Target, *TJ);
if (ErrorStr)
*ErrorStr = "target does not support JIT code generation";
return 0;
}