1 //===-- PPCMCInstLower.cpp - Convert PPC MachineInstr to an MCInst --------===//
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 contains code to lower PPC MachineInstrs to their corresponding
11 // MCInst records.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "PPC.h"
16 #include "MCTargetDesc/PPCMCExpr.h"
17 #include "llvm/ADT/SmallString.h"
18 #include "llvm/ADT/Twine.h"
19 #include "llvm/CodeGen/AsmPrinter.h"
20 #include "llvm/CodeGen/MachineFunction.h"
21 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
22 #include "llvm/IR/GlobalValue.h"
23 #include "llvm/MC/MCAsmInfo.h"
24 #include "llvm/MC/MCExpr.h"
25 #include "llvm/MC/MCInst.h"
26 #include "llvm/Target/Mangler.h"
27 using namespace llvm;
28 
29 static MachineModuleInfoMachO &getMachOMMI(AsmPrinter &AP) {
30   return AP.MMI->getObjFileInfo<MachineModuleInfoMachO>();
31 }
32 
33 
34 static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO, AsmPrinter &AP){
35   MCContext &Ctx = AP.OutContext;
36 
37   SmallString<128> Name;
38   if (!MO.isGlobal()) {
39     assert(MO.isSymbol() && "Isn't a symbol reference");
40     Name += AP.MAI->getGlobalPrefix();
41     Name += MO.getSymbolName();
42   } else {
43     const GlobalValue *GV = MO.getGlobal();
44     bool isImplicitlyPrivate = false;
45     if (MO.getTargetFlags() == PPCII::MO_DARWIN_STUB ||
46         (MO.getTargetFlags() & PPCII::MO_NLP_FLAG))
47       isImplicitlyPrivate = true;
48 
49     AP.Mang->getNameWithPrefix(Name, GV, isImplicitlyPrivate);
50   }
51 
52   // If the target flags on the operand changes the name of the symbol, do that
53   // before we return the symbol.
54   if (MO.getTargetFlags() == PPCII::MO_DARWIN_STUB) {
55     Name += "$stub";
56     const char *PGP = AP.MAI->getPrivateGlobalPrefix();
57     const char *Prefix = "";
58     if (!Name.startswith(PGP)) {
59       // http://llvm.org/bugs/show_bug.cgi?id=15763
60       // all stubs and lazy_ptrs should be local symbols, which need leading 'L'
61       Prefix = PGP;
62     }
63     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Twine(Prefix) + Twine(Name));
64     MachineModuleInfoImpl::StubValueTy &StubSym =
65       getMachOMMI(AP).getFnStubEntry(Sym);
66     if (StubSym.getPointer())
67       return Sym;
68 
69     if (MO.isGlobal()) {
70       StubSym =
71       MachineModuleInfoImpl::
72       StubValueTy(AP.Mang->getSymbol(MO.getGlobal()),
73                   !MO.getGlobal()->hasInternalLinkage());
74     } else {
75       Name.erase(Name.end()-5, Name.end());
76       StubSym =
77       MachineModuleInfoImpl::
78       StubValueTy(Ctx.GetOrCreateSymbol(Name.str()), false);
79     }
80     return Sym;
81   }
82 
83   // If the symbol reference is actually to a non_lazy_ptr, not to the symbol,
84   // then add the suffix.
85   if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG) {
86     Name += "$non_lazy_ptr";
87     MCSymbol *Sym = Ctx.GetOrCreateSymbol(Name.str());
88 
89     MachineModuleInfoMachO &MachO = getMachOMMI(AP);
90 
91     MachineModuleInfoImpl::StubValueTy &StubSym =
92       (MO.getTargetFlags() & PPCII::MO_NLP_HIDDEN_FLAG) ?
93          MachO.getHiddenGVStubEntry(Sym) : MachO.getGVStubEntry(Sym);
94 
95     if (StubSym.getPointer() == 0) {
96       assert(MO.isGlobal() && "Extern symbol not handled yet");
97       StubSym = MachineModuleInfoImpl::
98                    StubValueTy(AP.Mang->getSymbol(MO.getGlobal()),
99                                !MO.getGlobal()->hasInternalLinkage());
100     }
101     return Sym;
102   }
103 
104   return Ctx.GetOrCreateSymbol(Name.str());
105 }
106 
107 static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
108                               AsmPrinter &Printer, bool isDarwin) {
109   MCContext &Ctx = Printer.OutContext;
110   MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
111 
112   unsigned access = MO.getTargetFlags() & PPCII::MO_ACCESS_MASK;
113 
114   if (!isDarwin) {
115     switch (access) {
116       case PPCII::MO_HA16:
117         RefKind = MCSymbolRefExpr::VK_PPC_ADDR16_HA;
118         break;
119       case PPCII::MO_LO16:
120         RefKind = MCSymbolRefExpr::VK_PPC_ADDR16_LO;
121         break;
122       case PPCII::MO_TPREL16_HA:
123         RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_HA;
124         break;
125       case PPCII::MO_TPREL16_LO:
126         RefKind = MCSymbolRefExpr::VK_PPC_TPREL16_LO;
127         break;
128       case PPCII::MO_DTPREL16_LO:
129         RefKind = MCSymbolRefExpr::VK_PPC_DTPREL16_LO;
130         break;
131       case PPCII::MO_TLSLD16_LO:
132         RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD16_LO;
133         break;
134       case PPCII::MO_TOC16_LO:
135         RefKind = MCSymbolRefExpr::VK_PPC_TOC16_LO;
136         break;
137     }
138   }
139 
140   const MCExpr *Expr = MCSymbolRefExpr::Create(Symbol, RefKind, Ctx);
141 
142   if (!MO.isJTI() && MO.getOffset())
143     Expr = MCBinaryExpr::CreateAdd(Expr,
144                                    MCConstantExpr::Create(MO.getOffset(), Ctx),
145                                    Ctx);
146 
147   // Subtract off the PIC base if required.
148   if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG) {
149     const MachineFunction *MF = MO.getParent()->getParent()->getParent();
150 
151     const MCExpr *PB = MCSymbolRefExpr::Create(MF->getPICBaseSymbol(), Ctx);
152     Expr = MCBinaryExpr::CreateSub(Expr, PB, Ctx);
153   }
154 
155   // Add Darwin ha16() / lo16() markers if required.
156   if (isDarwin) {
157     switch (access) {
158       case PPCII::MO_HA16:
159         Expr = PPCMCExpr::CreateHa16(Expr, Ctx);
160         break;
161       case PPCII::MO_LO16:
162         Expr = PPCMCExpr::CreateLo16(Expr, Ctx);
163         break;
164     }
165   }
166 
167   return MCOperand::CreateExpr(Expr);
168 }
169 
170 void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
171                                         AsmPrinter &AP, bool isDarwin) {
172   OutMI.setOpcode(MI->getOpcode());
173 
174   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
175     const MachineOperand &MO = MI->getOperand(i);
176 
177     MCOperand MCOp;
178     switch (MO.getType()) {
179     default:
180       MI->dump();
181       llvm_unreachable("unknown operand type");
182     case MachineOperand::MO_Register:
183       assert(!MO.getSubReg() && "Subregs should be eliminated!");
184       MCOp = MCOperand::CreateReg(MO.getReg());
185       break;
186     case MachineOperand::MO_Immediate:
187       MCOp = MCOperand::CreateImm(MO.getImm());
188       break;
189     case MachineOperand::MO_MachineBasicBlock:
190       MCOp = MCOperand::CreateExpr(MCSymbolRefExpr::Create(
191                                       MO.getMBB()->getSymbol(), AP.OutContext));
192       break;
193     case MachineOperand::MO_GlobalAddress:
194     case MachineOperand::MO_ExternalSymbol:
195       MCOp = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP, isDarwin);
196       break;
197     case MachineOperand::MO_JumpTableIndex:
198       MCOp = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP, isDarwin);
199       break;
200     case MachineOperand::MO_ConstantPoolIndex:
201       MCOp = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP, isDarwin);
202       break;
203     case MachineOperand::MO_BlockAddress:
204       MCOp = GetSymbolRef(MO,AP.GetBlockAddressSymbol(MO.getBlockAddress()),AP,
205                           isDarwin);
206       break;
207     case MachineOperand::MO_RegisterMask:
208       continue;
209     }
210 
211     OutMI.addOperand(MCOp);
212   }
213 }
214