xref: /freebsd/contrib/llvm-project/llvm/lib/Target/PowerPC/PPCMCInstLower.cpp (revision dab59af3bcc7cb7ba01569d3044894b3e860ad56)
1 //===-- PPCMCInstLower.cpp - Convert PPC MachineInstr to an MCInst --------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains code to lower PPC MachineInstrs to their corresponding
10 // MCInst records.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "MCTargetDesc/PPCMCExpr.h"
15 #include "PPC.h"
16 #include "PPCMachineFunctionInfo.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/CodeGen/TargetLowering.h"
24 #include "llvm/IR/DataLayout.h"
25 #include "llvm/IR/GlobalValue.h"
26 #include "llvm/IR/Mangler.h"
27 #include "llvm/IR/Module.h"
28 #include "llvm/MC/MCAsmInfo.h"
29 #include "llvm/MC/MCExpr.h"
30 #include "llvm/MC/MCInst.h"
31 #include "llvm/Target/TargetLoweringObjectFile.h"
32 using namespace llvm;
33 
34 static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO,
35                                       AsmPrinter &AP) {
36   if (MO.isGlobal()) {
37     // Get the symbol from the global, accounting for XCOFF-specific
38     // intricacies (see TargetLoweringObjectFileXCOFF::getTargetSymbol).
39     const GlobalValue *GV = MO.getGlobal();
40     return AP.getSymbol(GV);
41   }
42 
43   assert(MO.isSymbol() && "Isn't a symbol reference");
44 
45   SmallString<128> Name;
46   const DataLayout &DL = AP.getDataLayout();
47   Mangler::getNameWithPrefix(Name, MO.getSymbolName(), DL);
48 
49   MCContext &Ctx = AP.OutContext;
50   MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
51   return Sym;
52 }
53 
54 static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
55                               AsmPrinter &Printer) {
56   MCContext &Ctx = Printer.OutContext;
57   MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
58 
59   unsigned access = MO.getTargetFlags();
60 
61   switch (access) {
62     case PPCII::MO_TPREL_LO:
63       RefKind = MCSymbolRefExpr::VK_PPC_TPREL_LO;
64       break;
65     case PPCII::MO_TPREL_HA:
66       RefKind = MCSymbolRefExpr::VK_PPC_TPREL_HA;
67       break;
68     case PPCII::MO_DTPREL_LO:
69       RefKind = MCSymbolRefExpr::VK_PPC_DTPREL_LO;
70       break;
71     case PPCII::MO_TLSLD_LO:
72       RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO;
73       break;
74     case PPCII::MO_TOC_LO:
75       RefKind = MCSymbolRefExpr::VK_PPC_TOC_LO;
76       break;
77     case PPCII::MO_TLS:
78       RefKind = MCSymbolRefExpr::VK_PPC_TLS;
79       break;
80     case PPCII::MO_TLS_PCREL_FLAG:
81       RefKind = MCSymbolRefExpr::VK_PPC_TLS_PCREL;
82       break;
83   }
84 
85   const TargetMachine &TM = Printer.TM;
86   const MachineInstr *MI = MO.getParent();
87   const MachineFunction *MF = MI->getMF();
88 
89   if (MO.getTargetFlags() == PPCII::MO_PLT)
90     RefKind = MCSymbolRefExpr::VK_PLT;
91   else if (MO.getTargetFlags() == PPCII::MO_PCREL_FLAG)
92     RefKind = MCSymbolRefExpr::VK_PCREL;
93   else if (MO.getTargetFlags() == PPCII::MO_GOT_PCREL_FLAG)
94     RefKind = MCSymbolRefExpr::VK_PPC_GOT_PCREL;
95   else if (MO.getTargetFlags() == PPCII::MO_TPREL_PCREL_FLAG)
96     RefKind = MCSymbolRefExpr::VK_TPREL;
97   else if (MO.getTargetFlags() == PPCII::MO_GOT_TLSGD_PCREL_FLAG)
98     RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSGD_PCREL;
99   else if (MO.getTargetFlags() == PPCII::MO_GOT_TLSLD_PCREL_FLAG)
100     RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_PCREL;
101   else if (MO.getTargetFlags() == PPCII::MO_GOT_TPREL_PCREL_FLAG)
102     RefKind = MCSymbolRefExpr::VK_PPC_GOT_TPREL_PCREL;
103   else if (MO.getTargetFlags() == PPCII::MO_TPREL_FLAG ||
104            MO.getTargetFlags() == PPCII::MO_TLSLD_FLAG) {
105     assert(MO.isGlobal() && "Only expecting a global MachineOperand here!");
106     TLSModel::Model Model = TM.getTLSModel(MO.getGlobal());
107     const PPCFunctionInfo *FuncInfo = MF->getInfo<PPCFunctionInfo>();
108     // For the local-[exec|dynamic] TLS model, we may generate the offset from
109     // the TLS base as an immediate operand (instead of using a TOC entry). Set
110     // the relocation type in case the result is used for purposes other than a
111     // TOC reference. In TOC reference cases, this result is discarded.
112     if (Model == TLSModel::LocalExec)
113       RefKind = MCSymbolRefExpr::VK_PPC_AIX_TLSLE;
114     else if (Model == TLSModel::LocalDynamic &&
115              FuncInfo->isAIXFuncUseTLSIEForLD())
116       // On AIX, TLS model opt may have turned local-dynamic accesses into
117       // initial-exec accesses.
118       RefKind = MCSymbolRefExpr::VK_PPC_AIX_TLSIE;
119     else if (Model == TLSModel::LocalDynamic)
120       RefKind = MCSymbolRefExpr::VK_PPC_AIX_TLSLD;
121   }
122 
123   const Module *M = MF->getFunction().getParent();
124   const PPCSubtarget *Subtarget = &(MF->getSubtarget<PPCSubtarget>());
125 
126   unsigned MIOpcode = MI->getOpcode();
127   assert((Subtarget->isUsingPCRelativeCalls() || MIOpcode != PPC::BL8_NOTOC) &&
128          "BL8_NOTOC is only valid when using PC Relative Calls.");
129   if (Subtarget->isUsingPCRelativeCalls()) {
130     if (MIOpcode == PPC::TAILB || MIOpcode == PPC::TAILB8 ||
131         MIOpcode == PPC::TCRETURNdi || MIOpcode == PPC::TCRETURNdi8 ||
132         MIOpcode == PPC::BL8_NOTOC || MIOpcode == PPC::BL8_NOTOC_RM) {
133       RefKind = MCSymbolRefExpr::VK_PPC_NOTOC;
134     }
135     if (MO.getTargetFlags() == PPCII::MO_PCREL_OPT_FLAG)
136       RefKind = MCSymbolRefExpr::VK_PPC_PCREL_OPT;
137   }
138 
139   const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, RefKind, Ctx);
140   // If -msecure-plt -fPIC, add 32768 to symbol.
141   if (Subtarget->isSecurePlt() && TM.isPositionIndependent() &&
142       M->getPICLevel() == PICLevel::BigPIC &&
143       MO.getTargetFlags() == PPCII::MO_PLT)
144     Expr =
145         MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(32768, Ctx), Ctx);
146 
147   if (!MO.isJTI() && MO.getOffset())
148     Expr = MCBinaryExpr::createAdd(Expr,
149                                    MCConstantExpr::create(MO.getOffset(), Ctx),
150                                    Ctx);
151 
152   // Subtract off the PIC base if required.
153   if (MO.getTargetFlags() == PPCII::MO_PIC_FLAG ||
154       MO.getTargetFlags() == PPCII::MO_PIC_HA_FLAG ||
155       MO.getTargetFlags() == PPCII::MO_PIC_LO_FLAG) {
156     const MachineFunction *MF = MO.getParent()->getParent()->getParent();
157 
158     const MCExpr *PB = MCSymbolRefExpr::create(MF->getPICBaseSymbol(), Ctx);
159     Expr = MCBinaryExpr::createSub(Expr, PB, Ctx);
160   }
161 
162   // Add ha16() / lo16() markers if required.
163   switch (access) {
164     case PPCII::MO_LO:
165     case PPCII::MO_PIC_LO_FLAG:
166       Expr = PPCMCExpr::createLo(Expr, Ctx);
167       break;
168     case PPCII::MO_HA:
169     case PPCII::MO_PIC_HA_FLAG:
170       Expr = PPCMCExpr::createHa(Expr, Ctx);
171       break;
172   }
173 
174   return MCOperand::createExpr(Expr);
175 }
176 
177 void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
178                                         AsmPrinter &AP) {
179   OutMI.setOpcode(MI->getOpcode());
180 
181   for (const MachineOperand &MO : MI->operands()) {
182     MCOperand MCOp;
183     if (LowerPPCMachineOperandToMCOperand(MO, MCOp, AP))
184       OutMI.addOperand(MCOp);
185   }
186 }
187 
188 bool llvm::LowerPPCMachineOperandToMCOperand(const MachineOperand &MO,
189                                              MCOperand &OutMO, AsmPrinter &AP) {
190   switch (MO.getType()) {
191   default:
192     llvm_unreachable("unknown operand type");
193   case MachineOperand::MO_Register:
194     assert(!MO.getSubReg() && "Subregs should be eliminated!");
195     assert(MO.getReg() > PPC::NoRegister &&
196            MO.getReg() < PPC::NUM_TARGET_REGS &&
197            "Invalid register for this target!");
198     // Ignore all implicit register operands.
199     if (MO.isImplicit())
200       return false;
201     OutMO = MCOperand::createReg(MO.getReg());
202     return true;
203   case MachineOperand::MO_Immediate:
204     OutMO = MCOperand::createImm(MO.getImm());
205     return true;
206   case MachineOperand::MO_MachineBasicBlock:
207     OutMO = MCOperand::createExpr(
208         MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), AP.OutContext));
209     return true;
210   case MachineOperand::MO_GlobalAddress:
211   case MachineOperand::MO_ExternalSymbol:
212     OutMO = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP);
213     return true;
214   case MachineOperand::MO_JumpTableIndex:
215     OutMO = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP);
216     return true;
217   case MachineOperand::MO_ConstantPoolIndex:
218     OutMO = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP);
219     return true;
220   case MachineOperand::MO_BlockAddress:
221     OutMO =
222         GetSymbolRef(MO, AP.GetBlockAddressSymbol(MO.getBlockAddress()), AP);
223     return true;
224   case MachineOperand::MO_MCSymbol:
225     OutMO = GetSymbolRef(MO, MO.getMCSymbol(), AP);
226     return true;
227   case MachineOperand::MO_RegisterMask:
228     return false;
229   }
230 }
231