1 //===-- ErlangGC.cpp - Erlang/OTP GC strategy -------------------*- C++ -*-===//
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 file implements the Erlang/OTP runtime-compatible garbage collector
11 // (e.g. defines safe points, root initialization etc.)
12 //
13 // The frametable emitter is in ErlangGCPrinter.cpp.
14 //
15 //===----------------------------------------------------------------------===//
16
17 #include "llvm/CodeGen/GCs.h"
18 #include "llvm/CodeGen/GCStrategy.h"
19 #include "llvm/CodeGen/MachineInstrBuilder.h"
20 #include "llvm/MC/MCContext.h"
21 #include "llvm/MC/MCSymbol.h"
22 #include "llvm/Target/TargetInstrInfo.h"
23 #include "llvm/Target/TargetMachine.h"
24
25 using namespace llvm;
26
27 namespace {
28
29 class ErlangGC : public GCStrategy {
30 MCSymbol *InsertLabel(MachineBasicBlock &MBB,
31 MachineBasicBlock::iterator MI,
32 DebugLoc DL) const;
33 public:
34 ErlangGC();
35 bool findCustomSafePoints(GCFunctionInfo &FI, MachineFunction &MF);
36 };
37
38 }
39
40 static GCRegistry::Add<ErlangGC>
41 X("erlang", "erlang-compatible garbage collector");
42
linkErlangGC()43 void llvm::linkErlangGC() { }
44
ErlangGC()45 ErlangGC::ErlangGC() {
46 InitRoots = false;
47 NeededSafePoints = 1 << GC::PostCall;
48 UsesMetadata = true;
49 CustomRoots = false;
50 CustomSafePoints = true;
51 }
52
InsertLabel(MachineBasicBlock & MBB,MachineBasicBlock::iterator MI,DebugLoc DL) const53 MCSymbol *ErlangGC::InsertLabel(MachineBasicBlock &MBB,
54 MachineBasicBlock::iterator MI,
55 DebugLoc DL) const {
56 const TargetInstrInfo* TII = MBB.getParent()->getTarget().getInstrInfo();
57 MCSymbol *Label = MBB.getParent()->getContext().CreateTempSymbol();
58 BuildMI(MBB, MI, DL, TII->get(TargetOpcode::GC_LABEL)).addSym(Label);
59 return Label;
60 }
61
findCustomSafePoints(GCFunctionInfo & FI,MachineFunction & MF)62 bool ErlangGC::findCustomSafePoints(GCFunctionInfo &FI, MachineFunction &MF) {
63 for (MachineFunction::iterator BBI = MF.begin(), BBE = MF.end(); BBI != BBE;
64 ++BBI)
65 for (MachineBasicBlock::iterator MI = BBI->begin(), ME = BBI->end();
66 MI != ME; ++MI)
67
68 if (MI->getDesc().isCall()) {
69
70 // Do not treat tail call sites as safe points.
71 if (MI->getDesc().isTerminator())
72 continue;
73
74 /* Code copied from VisitCallPoint(...) */
75 MachineBasicBlock::iterator RAI = MI; ++RAI;
76 MCSymbol* Label = InsertLabel(*MI->getParent(), RAI, MI->getDebugLoc());
77 FI.addSafePoint(GC::PostCall, Label, MI->getDebugLoc());
78 }
79
80 return false;
81 }
82