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//===-- ErlangGC.cpp - Erlang/OTP GC strategy -------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Erlang/OTP runtime-compatible garbage collector
// (e.g. defines safe points, root initialization etc.)
//
// The frametable emitter is in ErlangGCPrinter.cpp.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/GCs.h"
#include "llvm/CodeGen/GCStrategy.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
namespace {
class ErlangGC : public GCStrategy {
MCSymbol *InsertLabel(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
DebugLoc DL) const;
public:
ErlangGC();
bool findCustomSafePoints(GCFunctionInfo &FI, MachineFunction &MF) override;
};
}
static GCRegistry::Add<ErlangGC>
X("erlang", "erlang-compatible garbage collector");
void llvm::linkErlangGC() { }
ErlangGC::ErlangGC() {
InitRoots = false;
NeededSafePoints = 1 << GC::PostCall;
UsesMetadata = true;
CustomRoots = false;
CustomSafePoints = true;
}
MCSymbol *ErlangGC::InsertLabel(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
DebugLoc DL) const {
const TargetInstrInfo* TII = MBB.getParent()->getTarget().getInstrInfo();
MCSymbol *Label = MBB.getParent()->getContext().CreateTempSymbol();
BuildMI(MBB, MI, DL, TII->get(TargetOpcode::GC_LABEL)).addSym(Label);
return Label;
}
bool ErlangGC::findCustomSafePoints(GCFunctionInfo &FI, MachineFunction &MF) {
for (MachineFunction::iterator BBI = MF.begin(), BBE = MF.end(); BBI != BBE;
++BBI)
for (MachineBasicBlock::iterator MI = BBI->begin(), ME = BBI->end();
MI != ME; ++MI)
if (MI->getDesc().isCall()) {
// Do not treat tail call sites as safe points.
if (MI->getDesc().isTerminator())
continue;
/* Code copied from VisitCallPoint(...) */
MachineBasicBlock::iterator RAI = MI; ++RAI;
MCSymbol* Label = InsertLabel(*MI->getParent(), RAI, MI->getDebugLoc());
FI.addSafePoint(GC::PostCall, Label, MI->getDebugLoc());
}
return false;
}
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