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 "PPCSubtarget.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/CodeGen/TargetLowering.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/TargetLoweringObjectFile.h"
30 using namespace llvm;
31
GetSymbolFromOperand(const MachineOperand & MO,AsmPrinter & AP)32 static MCSymbol *GetSymbolFromOperand(const MachineOperand &MO,
33 AsmPrinter &AP) {
34 if (MO.isGlobal()) {
35 // Get the symbol from the global, accounting for XCOFF-specific
36 // intricacies (see TargetLoweringObjectFileXCOFF::getTargetSymbol).
37 const GlobalValue *GV = MO.getGlobal();
38 return AP.getSymbol(GV);
39 }
40
41 assert(MO.isSymbol() && "Isn't a symbol reference");
42
43 SmallString<128> Name;
44 const DataLayout &DL = AP.getDataLayout();
45 Mangler::getNameWithPrefix(Name, MO.getSymbolName(), DL);
46
47 MCContext &Ctx = AP.OutContext;
48 MCSymbol *Sym = Ctx.getOrCreateSymbol(Name);
49 return Sym;
50 }
51
GetSymbolRef(const MachineOperand & MO,const MCSymbol * Symbol,AsmPrinter & Printer)52 static MCOperand GetSymbolRef(const MachineOperand &MO, const MCSymbol *Symbol,
53 AsmPrinter &Printer) {
54 MCContext &Ctx = Printer.OutContext;
55 MCSymbolRefExpr::VariantKind RefKind = MCSymbolRefExpr::VK_None;
56
57 unsigned access = MO.getTargetFlags();
58
59 switch (access) {
60 case PPCII::MO_TPREL_LO:
61 RefKind = MCSymbolRefExpr::VK_PPC_TPREL_LO;
62 break;
63 case PPCII::MO_TPREL_HA:
64 RefKind = MCSymbolRefExpr::VK_PPC_TPREL_HA;
65 break;
66 case PPCII::MO_DTPREL_LO:
67 RefKind = MCSymbolRefExpr::VK_PPC_DTPREL_LO;
68 break;
69 case PPCII::MO_TLSLD_LO:
70 RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO;
71 break;
72 case PPCII::MO_TOC_LO:
73 RefKind = MCSymbolRefExpr::VK_PPC_TOC_LO;
74 break;
75 case PPCII::MO_TLS:
76 RefKind = MCSymbolRefExpr::VK_PPC_TLS;
77 break;
78 case PPCII::MO_TLS_PCREL_FLAG:
79 RefKind = MCSymbolRefExpr::VK_PPC_TLS_PCREL;
80 break;
81 }
82
83 const TargetMachine &TM = Printer.TM;
84
85 if (MO.getTargetFlags() == PPCII::MO_PLT)
86 RefKind = MCSymbolRefExpr::VK_PLT;
87 else if (MO.getTargetFlags() == PPCII::MO_PCREL_FLAG)
88 RefKind = MCSymbolRefExpr::VK_PCREL;
89 else if (MO.getTargetFlags() == PPCII::MO_GOT_PCREL_FLAG)
90 RefKind = MCSymbolRefExpr::VK_PPC_GOT_PCREL;
91 else if (MO.getTargetFlags() == PPCII::MO_TPREL_PCREL_FLAG)
92 RefKind = MCSymbolRefExpr::VK_TPREL;
93 else if (MO.getTargetFlags() == PPCII::MO_GOT_TLSGD_PCREL_FLAG)
94 RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSGD_PCREL;
95 else if (MO.getTargetFlags() == PPCII::MO_GOT_TLSLD_PCREL_FLAG)
96 RefKind = MCSymbolRefExpr::VK_PPC_GOT_TLSLD_PCREL;
97 else if (MO.getTargetFlags() == PPCII::MO_GOT_TPREL_PCREL_FLAG)
98 RefKind = MCSymbolRefExpr::VK_PPC_GOT_TPREL_PCREL;
99 else if (MO.getTargetFlags() == PPCII::MO_TPREL_FLAG) {
100 assert(MO.isGlobal() && "Only expecting a global MachineOperand here!");
101 TLSModel::Model Model = TM.getTLSModel(MO.getGlobal());
102 // For the local-exec TLS model, we may generate the offset from the TLS
103 // base as an immediate operand (instead of using a TOC entry).
104 // Set the relocation type in case the result is used for purposes other
105 // than a TOC reference. In TOC reference cases, this result is discarded.
106 if (Model == TLSModel::LocalExec)
107 RefKind = MCSymbolRefExpr::VK_PPC_AIX_TLSLE;
108 }
109
110 const MachineInstr *MI = MO.getParent();
111 const MachineFunction *MF = MI->getMF();
112 const Module *M = MF->getFunction().getParent();
113 const PPCSubtarget *Subtarget = &(MF->getSubtarget<PPCSubtarget>());
114
115 unsigned MIOpcode = MI->getOpcode();
116 assert((Subtarget->isUsingPCRelativeCalls() || MIOpcode != PPC::BL8_NOTOC) &&
117 "BL8_NOTOC is only valid when using PC Relative Calls.");
118 if (Subtarget->isUsingPCRelativeCalls()) {
119 if (MIOpcode == PPC::TAILB || MIOpcode == PPC::TAILB8 ||
120 MIOpcode == PPC::TCRETURNdi || MIOpcode == PPC::TCRETURNdi8 ||
121 MIOpcode == PPC::BL8_NOTOC || MIOpcode == PPC::BL8_NOTOC_RM) {
122 RefKind = MCSymbolRefExpr::VK_PPC_NOTOC;
123 }
124 if (MO.getTargetFlags() == PPCII::MO_PCREL_OPT_FLAG)
125 RefKind = MCSymbolRefExpr::VK_PPC_PCREL_OPT;
126 }
127
128 const MCExpr *Expr = MCSymbolRefExpr::create(Symbol, RefKind, Ctx);
129 // If -msecure-plt -fPIC, add 32768 to symbol.
130 if (Subtarget->isSecurePlt() && TM.isPositionIndependent() &&
131 M->getPICLevel() == PICLevel::BigPIC &&
132 MO.getTargetFlags() == PPCII::MO_PLT)
133 Expr =
134 MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(32768, Ctx), Ctx);
135
136 if (!MO.isJTI() && MO.getOffset())
137 Expr = MCBinaryExpr::createAdd(Expr,
138 MCConstantExpr::create(MO.getOffset(), Ctx),
139 Ctx);
140
141 // Subtract off the PIC base if required.
142 if (MO.getTargetFlags() == PPCII::MO_PIC_FLAG ||
143 MO.getTargetFlags() == PPCII::MO_PIC_HA_FLAG ||
144 MO.getTargetFlags() == PPCII::MO_PIC_LO_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 case PPCII::MO_PIC_LO_FLAG:
155 Expr = PPCMCExpr::createLo(Expr, Ctx);
156 break;
157 case PPCII::MO_HA:
158 case PPCII::MO_PIC_HA_FLAG:
159 Expr = PPCMCExpr::createHa(Expr, Ctx);
160 break;
161 }
162
163 return MCOperand::createExpr(Expr);
164 }
165
LowerPPCMachineInstrToMCInst(const MachineInstr * MI,MCInst & OutMI,AsmPrinter & AP)166 void llvm::LowerPPCMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
167 AsmPrinter &AP) {
168 OutMI.setOpcode(MI->getOpcode());
169
170 for (const MachineOperand &MO : MI->operands()) {
171 MCOperand MCOp;
172 if (LowerPPCMachineOperandToMCOperand(MO, MCOp, AP))
173 OutMI.addOperand(MCOp);
174 }
175 }
176
LowerPPCMachineOperandToMCOperand(const MachineOperand & MO,MCOperand & OutMO,AsmPrinter & AP)177 bool llvm::LowerPPCMachineOperandToMCOperand(const MachineOperand &MO,
178 MCOperand &OutMO, AsmPrinter &AP) {
179 switch (MO.getType()) {
180 default:
181 llvm_unreachable("unknown operand type");
182 case MachineOperand::MO_Register:
183 assert(!MO.getSubReg() && "Subregs should be eliminated!");
184 assert(MO.getReg() > PPC::NoRegister &&
185 MO.getReg() < PPC::NUM_TARGET_REGS &&
186 "Invalid register for this target!");
187 // Ignore all implicit register operands.
188 if (MO.isImplicit())
189 return false;
190 OutMO = MCOperand::createReg(MO.getReg());
191 return true;
192 case MachineOperand::MO_Immediate:
193 OutMO = MCOperand::createImm(MO.getImm());
194 return true;
195 case MachineOperand::MO_MachineBasicBlock:
196 OutMO = MCOperand::createExpr(
197 MCSymbolRefExpr::create(MO.getMBB()->getSymbol(), AP.OutContext));
198 return true;
199 case MachineOperand::MO_GlobalAddress:
200 case MachineOperand::MO_ExternalSymbol:
201 OutMO = GetSymbolRef(MO, GetSymbolFromOperand(MO, AP), AP);
202 return true;
203 case MachineOperand::MO_JumpTableIndex:
204 OutMO = GetSymbolRef(MO, AP.GetJTISymbol(MO.getIndex()), AP);
205 return true;
206 case MachineOperand::MO_ConstantPoolIndex:
207 OutMO = GetSymbolRef(MO, AP.GetCPISymbol(MO.getIndex()), AP);
208 return true;
209 case MachineOperand::MO_BlockAddress:
210 OutMO =
211 GetSymbolRef(MO, AP.GetBlockAddressSymbol(MO.getBlockAddress()), AP);
212 return true;
213 case MachineOperand::MO_MCSymbol:
214 OutMO = GetSymbolRef(MO, MO.getMCSymbol(), AP);
215 return true;
216 case MachineOperand::MO_RegisterMask:
217 return false;
218 }
219 }
220