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