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 "PPCSubtarget.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/ADT/Twine.h"
20 #include "llvm/CodeGen/AsmPrinter.h"
21 #include "llvm/CodeGen/MachineFunction.h"
22 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
23 #include "llvm/IR/DataLayout.h"
24 #include "llvm/IR/GlobalValue.h"
25 #include "llvm/IR/Mangler.h"
26 #include "llvm/MC/MCAsmInfo.h"
27 #include "llvm/MC/MCExpr.h"
28 #include "llvm/MC/MCInst.h"
29 #include "llvm/Target/TargetLowering.h"
30 #include "llvm/Target/TargetLoweringObjectFile.h"
31 using namespace llvm;
32 
33 static MachineModuleInfoMachO &getMachOMMI(AsmPrinter &AP) {
34   return AP.MMI->getObjFileInfo<MachineModuleInfoMachO>();
35 }
36 
37 
38 static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO, AsmPrinter &AP){
39   const TargetMachine &TM = AP.TM;
40   Mangler *Mang = AP.Mang;
41   const DataLayout &DL = AP.getDataLayout();
42   MCContext &Ctx = AP.OutContext;
43   bool isDarwin = TM.getTargetTriple().isOSDarwin();
44 
45   SmallString<128> Name;
46   StringRef Suffix;
47   if (MO.getTargetFlags() == PPCII::MO_PLT_OR_STUB) {
48     if (isDarwin)
49       Suffix = "$stub";
50   } else if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG)
51     Suffix = "$non_lazy_ptr";
52 
53   if (!Suffix.empty())
54     Name += DL.getPrivateGlobalPrefix();
55 
56   unsigned PrefixLen = Name.size();
57 
58   if (!MO.isGlobal()) {
59     assert(MO.isSymbol() && "Isn't a symbol reference");
60     Mangler::getNameWithPrefix(Name, MO.getSymbolName(), DL);
61   } else {
62     const GlobalValue *GV = MO.getGlobal();
63     TM.getNameWithPrefix(Name, GV, *Mang);
64   }
65 
66   unsigned OrigLen = Name.size() - PrefixLen;
67 
68   Name += Suffix;
69   MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
70   StringRef OrigName = StringRef(Name).substr(PrefixLen, OrigLen);
71 
72   // If the target flags on the operand changes the name of the symbol, do that
73   // before we return the symbol.
74   if (MO.getTargetFlags() == PPCII::MO_PLT_OR_STUB && isDarwin) {
75     MachineModuleInfoImpl::StubValueTy &StubSym =
76       getMachOMMI(AP).getFnStubEntry(Sym);
77     if (StubSym.getPointer())
78       return Sym;
79 
80     if (MO.isGlobal()) {
81       StubSym =
82       MachineModuleInfoImpl::
83       StubValueTy(AP.getSymbol(MO.getGlobal()),
84                   !MO.getGlobal()->hasInternalLinkage());
85     } else {
86       StubSym =
87       MachineModuleInfoImpl::
88       StubValueTy(Ctx.getOrCreateSymbol(OrigName), false);
89     }
90     return Sym;
91   }
92 
93   // If the symbol reference is actually to a non_lazy_ptr, not to the symbol,
94   // then add the suffix.
95   if (MO.getTargetFlags() & PPCII::MO_NLP_FLAG) {
96     MachineModuleInfoMachO &MachO = getMachOMMI(AP);
97 
98     MachineModuleInfoImpl::StubValueTy &StubSym = MachO.getGVStubEntry(Sym);
99 
100     if (!StubSym.getPointer()) {
101       assert(MO.isGlobal() && "Extern symbol not handled yet");
102       StubSym = MachineModuleInfoImpl::
103                    StubValueTy(AP.getSymbol(MO.getGlobal()),
104                                !MO.getGlobal()->hasInternalLinkage());
105     }
106     return Sym;
107   }
108 
109   return Sym;
110 }
111 
112 static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
113                               AsmPrinter &Printer, bool isDarwin) {
114   MCContext &Ctx = Printer.OutContext;
115   MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
116 
117   unsigned access = MO.getTargetFlags() & PPCII::MO_ACCESS_MASK;
118 
119   switch (access) {
120     case PPCII::MO_TPREL_LO:
121       RefKind = MCSymbolRefExpr::VK_PPC_TPREL_LO;
122       break;
123     case PPCII::MO_TPREL_HA:
124       RefKind = MCSymbolRefExpr::VK_PPC_TPREL_HA;
125       break;
126     case PPCII::MO_DTPREL_LO:
127       RefKind = MCSymbolRefExpr::VK_PPC_DTPREL_LO;
128       break;
129     case PPCII::MO_TLSLD_LO:
130       RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO;
131       break;
132     case PPCII::MO_TOC_LO:
133       RefKind = MCSymbolRefExpr::VK_PPC_TOC_LO;
134       break;
135     case PPCII::MO_TLS:
136       RefKind = MCSymbolRefExpr::VK_PPC_TLS;
137       break;
138   }
139 
140   if (MO.getTargetFlags() == PPCII::MO_PLT_OR_STUB && !isDarwin)
141     RefKind = MCSymbolRefExpr::VK_PLT;
142 
143   const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, RefKind, Ctx);
144 
145   if (!MO.isJTI() && MO.getOffset())
146     Expr = MCBinaryExpr::createAdd(Expr,
147                                    MCConstantExpr::create(MO.getOffset(), Ctx),
148                                    Ctx);
149 
150   // Subtract off the PIC base if required.
151   if (MO.getTargetFlags() & PPCII::MO_PIC_FLAG) {
152     const MachineFunction *MF = MO.getParent()->getParent()->getParent();
153 
154     const MCExpr *PB = MCSymbolRefExpr::create(MF->getPICBaseSymbol(), Ctx);
155     Expr = MCBinaryExpr::createSub(Expr, PB, Ctx);
156   }
157 
158   // Add ha16() / lo16() markers if required.
159   switch (access) {
160     case PPCII::MO_LO:
161       Expr = PPCMCExpr::createLo(Expr, isDarwin, Ctx);
162       break;
163     case PPCII::MO_HA:
164       Expr = PPCMCExpr::createHa(Expr, isDarwin, Ctx);
165       break;
166   }
167 
168   return MCOperand::createExpr(Expr);
169 }
170 
171 void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
172                                         AsmPrinter &AP, bool isDarwin) {
173   OutMI.setOpcode(MI->getOpcode());
174 
175   for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
176     const MachineOperand &MO = MI->getOperand(i);
177 
178     MCOperand MCOp;
179     switch (MO.getType()) {
180     default:
181       MI->dump();
182       llvm_unreachable("unknown operand type");
183     case MachineOperand::MO_Register:
184       assert(!MO.getSubReg() && "Subregs should be eliminated!");
185       assert(MO.getReg() > PPC::NoRegister &&
186              MO.getReg() < PPC::NUM_TARGET_REGS &&
187              "Invalid register for this target!");
188       MCOp = MCOperand::createReg(MO.getReg());
189       break;
190     case MachineOperand::MO_Immediate:
191       MCOp = MCOperand::createImm(MO.getImm());
192       break;
193     case MachineOperand::MO_MachineBasicBlock:
194       MCOp = MCOperand::createExpr(MCSymbolRefExpr::create(
195                                       MO.getMBB()->getSymbol(), AP.OutContext));
196       break;
197     case MachineOperand::MO_GlobalAddress:
198     case MachineOperand::MO_ExternalSymbol:
199       MCOp = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP, isDarwin);
200       break;
201     case MachineOperand::MO_JumpTableIndex:
202       MCOp = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP, isDarwin);
203       break;
204     case MachineOperand::MO_ConstantPoolIndex:
205       MCOp = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP, isDarwin);
206       break;
207     case MachineOperand::MO_BlockAddress:
208       MCOp = GetSymbolRef(MO,AP.GetBlockAddressSymbol(MO.getBlockAddress()),AP,
209                           isDarwin);
210       break;
211     case MachineOperand::MO_RegisterMask:
212       continue;
213     }
214 
215     OutMI.addOperand(MCOp);
216   }
217 }
218