1 //===-- PPCCodeEmitter.cpp - JIT Code Emitter for PowerPC -----------------===//
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 defines the PowerPC 32-bit CodeEmitter and associated machinery to
11 // JIT-compile bitcode to native PowerPC.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "PPC.h"
16 #include "PPCRelocations.h"
17 #include "PPCTargetMachine.h"
18 #include "llvm/CodeGen/JITCodeEmitter.h"
19 #include "llvm/CodeGen/MachineFunctionPass.h"
20 #include "llvm/CodeGen/MachineInstrBuilder.h"
21 #include "llvm/CodeGen/MachineModuleInfo.h"
22 #include "llvm/IR/Module.h"
23 #include "llvm/PassManager.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Support/raw_ostream.h"
26 #include "llvm/Target/TargetOptions.h"
27 using namespace llvm;
28
29 namespace {
30 class PPCCodeEmitter : public MachineFunctionPass {
31 TargetMachine &TM;
32 JITCodeEmitter &MCE;
33 MachineModuleInfo *MMI;
34
getAnalysisUsage(AnalysisUsage & AU) const35 void getAnalysisUsage(AnalysisUsage &AU) const {
36 AU.addRequired<MachineModuleInfo>();
37 MachineFunctionPass::getAnalysisUsage(AU);
38 }
39
40 static char ID;
41
42 /// MovePCtoLROffset - When/if we see a MovePCtoLR instruction, we record
43 /// its address in the function into this pointer.
44 void *MovePCtoLROffset;
45 public:
46
PPCCodeEmitter(TargetMachine & tm,JITCodeEmitter & mce)47 PPCCodeEmitter(TargetMachine &tm, JITCodeEmitter &mce)
48 : MachineFunctionPass(ID), TM(tm), MCE(mce) {}
49
50 /// getBinaryCodeForInstr - This function, generated by the
51 /// CodeEmitterGenerator using TableGen, produces the binary encoding for
52 /// machine instructions.
53 uint64_t getBinaryCodeForInstr(const MachineInstr &MI) const;
54
55
56 MachineRelocation GetRelocation(const MachineOperand &MO,
57 unsigned RelocID) const;
58
59 /// getMachineOpValue - evaluates the MachineOperand of a given MachineInstr
60 unsigned getMachineOpValue(const MachineInstr &MI,
61 const MachineOperand &MO) const;
62
63 unsigned get_crbitm_encoding(const MachineInstr &MI, unsigned OpNo) const;
64 unsigned getDirectBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
65 unsigned getCondBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
66 unsigned getAbsDirectBrEncoding(const MachineInstr &MI,
67 unsigned OpNo) const;
68 unsigned getAbsCondBrEncoding(const MachineInstr &MI, unsigned OpNo) const;
69
70 unsigned getImm16Encoding(const MachineInstr &MI, unsigned OpNo) const;
71 unsigned getMemRIEncoding(const MachineInstr &MI, unsigned OpNo) const;
72 unsigned getMemRIXEncoding(const MachineInstr &MI, unsigned OpNo) const;
73 unsigned getTLSRegEncoding(const MachineInstr &MI, unsigned OpNo) const;
74 unsigned getTLSCallEncoding(const MachineInstr &MI, unsigned OpNo) const;
75
getPassName() const76 const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
77
78 /// runOnMachineFunction - emits the given MachineFunction to memory
79 ///
80 bool runOnMachineFunction(MachineFunction &MF);
81
82 /// emitBasicBlock - emits the given MachineBasicBlock to memory
83 ///
84 void emitBasicBlock(MachineBasicBlock &MBB);
85 };
86 }
87
88 char PPCCodeEmitter::ID = 0;
89
90 /// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
91 /// to the specified MCE object.
createPPCJITCodeEmitterPass(PPCTargetMachine & TM,JITCodeEmitter & JCE)92 FunctionPass *llvm::createPPCJITCodeEmitterPass(PPCTargetMachine &TM,
93 JITCodeEmitter &JCE) {
94 return new PPCCodeEmitter(TM, JCE);
95 }
96
runOnMachineFunction(MachineFunction & MF)97 bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
98 assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
99 MF.getTarget().getRelocationModel() != Reloc::Static) &&
100 "JIT relocation model must be set to static or default!");
101
102 MMI = &getAnalysis<MachineModuleInfo>();
103 MCE.setModuleInfo(MMI);
104 do {
105 MovePCtoLROffset = 0;
106 MCE.startFunction(MF);
107 for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
108 emitBasicBlock(*BB);
109 } while (MCE.finishFunction(MF));
110
111 return false;
112 }
113
emitBasicBlock(MachineBasicBlock & MBB)114 void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
115 MCE.StartMachineBasicBlock(&MBB);
116
117 for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
118 const MachineInstr &MI = *I;
119 MCE.processDebugLoc(MI.getDebugLoc(), true);
120 switch (MI.getOpcode()) {
121 default:
122 MCE.emitWordBE(getBinaryCodeForInstr(MI));
123 break;
124 case TargetOpcode::PROLOG_LABEL:
125 case TargetOpcode::EH_LABEL:
126 MCE.emitLabel(MI.getOperand(0).getMCSymbol());
127 break;
128 case TargetOpcode::IMPLICIT_DEF:
129 case TargetOpcode::KILL:
130 break; // pseudo opcode, no side effects
131 case PPC::MovePCtoLR:
132 case PPC::MovePCtoLR8:
133 assert(TM.getRelocationModel() == Reloc::PIC_);
134 MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
135 MCE.emitWordBE(0x48000005); // bl 1
136 break;
137 }
138 MCE.processDebugLoc(MI.getDebugLoc(), false);
139 }
140 }
141
get_crbitm_encoding(const MachineInstr & MI,unsigned OpNo) const142 unsigned PPCCodeEmitter::get_crbitm_encoding(const MachineInstr &MI,
143 unsigned OpNo) const {
144 const MachineOperand &MO = MI.getOperand(OpNo);
145 assert((MI.getOpcode() == PPC::MTOCRF || MI.getOpcode() == PPC::MTOCRF8 ||
146 MI.getOpcode() == PPC::MFOCRF || MI.getOpcode() == PPC::MFOCRF8) &&
147 (MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7));
148 return 0x80 >> TM.getRegisterInfo()->getEncodingValue(MO.getReg());
149 }
150
GetRelocation(const MachineOperand & MO,unsigned RelocID) const151 MachineRelocation PPCCodeEmitter::GetRelocation(const MachineOperand &MO,
152 unsigned RelocID) const {
153 // If in PIC mode, we need to encode the negated address of the
154 // 'movepctolr' into the unrelocated field. After relocation, we'll have
155 // &gv-&movepctolr-4 in the imm field. Once &movepctolr is added to the imm
156 // field, we get &gv. This doesn't happen for branch relocations, which are
157 // always implicitly pc relative.
158 intptr_t Cst = 0;
159 if (TM.getRelocationModel() == Reloc::PIC_) {
160 assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
161 Cst = -(intptr_t)MovePCtoLROffset - 4;
162 }
163
164 if (MO.isGlobal())
165 return MachineRelocation::getGV(MCE.getCurrentPCOffset(), RelocID,
166 const_cast<GlobalValue *>(MO.getGlobal()),
167 Cst, isa<Function>(MO.getGlobal()));
168 if (MO.isSymbol())
169 return MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
170 RelocID, MO.getSymbolName(), Cst);
171 if (MO.isCPI())
172 return MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
173 RelocID, MO.getIndex(), Cst);
174
175 if (MO.isMBB())
176 return MachineRelocation::getBB(MCE.getCurrentPCOffset(),
177 RelocID, MO.getMBB());
178
179 assert(MO.isJTI());
180 return MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
181 RelocID, MO.getIndex(), Cst);
182 }
183
getDirectBrEncoding(const MachineInstr & MI,unsigned OpNo) const184 unsigned PPCCodeEmitter::getDirectBrEncoding(const MachineInstr &MI,
185 unsigned OpNo) const {
186 const MachineOperand &MO = MI.getOperand(OpNo);
187 if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
188
189 MCE.addRelocation(GetRelocation(MO, PPC::reloc_pcrel_bx));
190 return 0;
191 }
192
getCondBrEncoding(const MachineInstr & MI,unsigned OpNo) const193 unsigned PPCCodeEmitter::getCondBrEncoding(const MachineInstr &MI,
194 unsigned OpNo) const {
195 const MachineOperand &MO = MI.getOperand(OpNo);
196 MCE.addRelocation(GetRelocation(MO, PPC::reloc_pcrel_bcx));
197 return 0;
198 }
199
getAbsDirectBrEncoding(const MachineInstr & MI,unsigned OpNo) const200 unsigned PPCCodeEmitter::getAbsDirectBrEncoding(const MachineInstr &MI,
201 unsigned OpNo) const {
202 const MachineOperand &MO = MI.getOperand(OpNo);
203 if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
204
205 llvm_unreachable("Absolute branch relocations unsupported on the old JIT.");
206 }
207
getAbsCondBrEncoding(const MachineInstr & MI,unsigned OpNo) const208 unsigned PPCCodeEmitter::getAbsCondBrEncoding(const MachineInstr &MI,
209 unsigned OpNo) const {
210 llvm_unreachable("Absolute branch relocations unsupported on the old JIT.");
211 }
212
getImm16Encoding(const MachineInstr & MI,unsigned OpNo) const213 unsigned PPCCodeEmitter::getImm16Encoding(const MachineInstr &MI,
214 unsigned OpNo) const {
215 const MachineOperand &MO = MI.getOperand(OpNo);
216 if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
217
218 unsigned RelocID;
219 switch (MO.getTargetFlags() & PPCII::MO_ACCESS_MASK) {
220 default: llvm_unreachable("Unsupported target operand flags!");
221 case PPCII::MO_LO: RelocID = PPC::reloc_absolute_low; break;
222 case PPCII::MO_HA: RelocID = PPC::reloc_absolute_high; break;
223 }
224
225 MCE.addRelocation(GetRelocation(MO, RelocID));
226 return 0;
227 }
228
getMemRIEncoding(const MachineInstr & MI,unsigned OpNo) const229 unsigned PPCCodeEmitter::getMemRIEncoding(const MachineInstr &MI,
230 unsigned OpNo) const {
231 // Encode (imm, reg) as a memri, which has the low 16-bits as the
232 // displacement and the next 5 bits as the register #.
233 assert(MI.getOperand(OpNo+1).isReg());
234 unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1)) << 16;
235
236 const MachineOperand &MO = MI.getOperand(OpNo);
237 if (MO.isImm())
238 return (getMachineOpValue(MI, MO) & 0xFFFF) | RegBits;
239
240 // Add a fixup for the displacement field.
241 MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low));
242 return RegBits;
243 }
244
getMemRIXEncoding(const MachineInstr & MI,unsigned OpNo) const245 unsigned PPCCodeEmitter::getMemRIXEncoding(const MachineInstr &MI,
246 unsigned OpNo) const {
247 // Encode (imm, reg) as a memrix, which has the low 14-bits as the
248 // displacement and the next 5 bits as the register #.
249 assert(MI.getOperand(OpNo+1).isReg());
250 unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1)) << 14;
251
252 const MachineOperand &MO = MI.getOperand(OpNo);
253 if (MO.isImm())
254 return ((getMachineOpValue(MI, MO) >> 2) & 0x3FFF) | RegBits;
255
256 MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low_ix));
257 return RegBits;
258 }
259
260
getTLSRegEncoding(const MachineInstr & MI,unsigned OpNo) const261 unsigned PPCCodeEmitter::getTLSRegEncoding(const MachineInstr &MI,
262 unsigned OpNo) const {
263 llvm_unreachable("TLS not supported on the old JIT.");
264 return 0;
265 }
266
getTLSCallEncoding(const MachineInstr & MI,unsigned OpNo) const267 unsigned PPCCodeEmitter::getTLSCallEncoding(const MachineInstr &MI,
268 unsigned OpNo) const {
269 llvm_unreachable("TLS not supported on the old JIT.");
270 return 0;
271 }
272
getMachineOpValue(const MachineInstr & MI,const MachineOperand & MO) const273 unsigned PPCCodeEmitter::getMachineOpValue(const MachineInstr &MI,
274 const MachineOperand &MO) const {
275
276 if (MO.isReg()) {
277 // MTOCRF/MFOCRF should go through get_crbitm_encoding for the CR operand.
278 // The GPR operand should come through here though.
279 assert((MI.getOpcode() != PPC::MTOCRF && MI.getOpcode() != PPC::MTOCRF8 &&
280 MI.getOpcode() != PPC::MFOCRF && MI.getOpcode() != PPC::MFOCRF8) ||
281 MO.getReg() < PPC::CR0 || MO.getReg() > PPC::CR7);
282 return TM.getRegisterInfo()->getEncodingValue(MO.getReg());
283 }
284
285 assert(MO.isImm() &&
286 "Relocation required in an instruction that we cannot encode!");
287 return MO.getImm();
288 }
289
290 #include "PPCGenCodeEmitter.inc"
291