llvm-6502/lib/Target/TargetMachineRegistry.cpp

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//===-- TargetMachineRegistry.cpp - Target Auto Registration Impl ---------===//
//
// 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 file exposes the RegisterTarget class, which TargetMachine
// implementations should use to register themselves with the system. This file
// also exposes the TargetMachineRegistry class, which allows tools to inspect
// all of registered targets.
//
//===----------------------------------------------------------------------===//
#include "llvm/Target/TargetMachineRegistry.h"
#include <algorithm>
using namespace llvm;
/// List - This is the main list of all of the registered target machines.
const TargetMachineRegistry::Entry *TargetMachineRegistry::List = 0;
/// Listeners - All of the listeners registered to get notified when new targets
/// are loaded.
static TargetRegistrationListener *Listeners = 0;
TargetMachineRegistry::Entry::Entry(const char *N, const char *SD,
TargetMachine *(*CF)(const Module &,const std::string &),
unsigned (*MMF)(const Module &M), unsigned (*JMF)())
: Name(N), ShortDesc(SD), CtorFn(CF), ModuleMatchQualityFn(MMF),
JITMatchQualityFn(JMF), Next(List) {
List = this;
for (TargetRegistrationListener *L = Listeners; L; L = L->getNext())
L->targetRegistered(this);
}
TargetRegistrationListener::TargetRegistrationListener() {
Next = Listeners;
if (Next) Next->Prev = &Next;
Prev = &Listeners;
Listeners = this;
}
TargetRegistrationListener::~TargetRegistrationListener() {
*Prev = Next;
}
/// getClosestStaticTargetForModule - Given an LLVM module, pick the best target
/// that is compatible with the module. If no close target can be found, this
/// returns null and sets the Error string to a reason.
const TargetMachineRegistry::Entry *
TargetMachineRegistry::getClosestStaticTargetForModule(const Module &M,
std::string &Error) {
std::vector<std::pair<unsigned, const Entry *> > UsableTargets;
for (const Entry *E = getList(); E; E = E->getNext())
if (unsigned Qual = E->ModuleMatchQualityFn(M))
UsableTargets.push_back(std::make_pair(Qual, E));
if (UsableTargets.empty()) {
Error = "No available targets are compatible with this module";
return 0;
} else if (UsableTargets.size() == 1)
return UsableTargets.back().second;
// Otherwise, take the best target, but make sure we don't have to equally
// good best targets.
std::sort(UsableTargets.begin(), UsableTargets.end());
if (UsableTargets.back().first ==UsableTargets[UsableTargets.size()-2].first){
Error = "Cannot choose between targets \"" +
std::string(UsableTargets.back().second->Name) + "\" and \"" +
std::string(UsableTargets[UsableTargets.size()-2].second->Name) + "\"";
return 0;
}
return UsableTargets.back().second;
}
/// getClosestTargetForJIT - Given an LLVM module, pick the best target that
/// is compatible with the current host and the specified module. If no
/// close target can be found, this returns null and sets the Error string
/// to a reason.
const TargetMachineRegistry::Entry *
TargetMachineRegistry::getClosestTargetForJIT(std::string &Error) {
std::vector<std::pair<unsigned, const Entry *> > UsableTargets;
for (const Entry *E = getList(); E; E = E->getNext())
if (unsigned Qual = E->JITMatchQualityFn())
UsableTargets.push_back(std::make_pair(Qual, E));
if (UsableTargets.empty()) {
Error = "No JIT is available for this host";
return 0;
} else if (UsableTargets.size() == 1)
return UsableTargets.back().second;
// Otherwise, take the best target. If there is a tie, just pick one.
unsigned MaxQual = UsableTargets.front().first;
const Entry *MaxQualTarget = UsableTargets.front().second;
for (unsigned i = 1, e = UsableTargets.size(); i != e; ++i)
if (UsableTargets[i].first > MaxQual) {
MaxQual = UsableTargets[i].first;
MaxQualTarget = UsableTargets[i].second;
}
return MaxQualTarget;
}