1 //===-- PPCCodeEmitter.cpp - JIT Code Emitter for PowerPC32 -------*- C++ -*-=//
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 "PPCTargetMachine.h"
16 #include "PPCRelocations.h"
17 #include "PPC.h"
18 #include "llvm/Module.h"
19 #include "llvm/PassManager.h"
20 #include "llvm/CodeGen/JITCodeEmitter.h"
21 #include "llvm/CodeGen/MachineFunctionPass.h"
22 #include "llvm/CodeGen/MachineInstrBuilder.h"
23 #include "llvm/CodeGen/MachineModuleInfo.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 unsigned 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
67 unsigned getHA16Encoding(const MachineInstr &MI, unsigned OpNo) const;
68 unsigned getLO16Encoding(const MachineInstr &MI, unsigned OpNo) const;
69 unsigned getMemRIEncoding(const MachineInstr &MI, unsigned OpNo) const;
70 unsigned getMemRIXEncoding(const MachineInstr &MI, unsigned OpNo) const;
71
getPassName() const72 const char *getPassName() const { return "PowerPC Machine Code Emitter"; }
73
74 /// runOnMachineFunction - emits the given MachineFunction to memory
75 ///
76 bool runOnMachineFunction(MachineFunction &MF);
77
78 /// emitBasicBlock - emits the given MachineBasicBlock to memory
79 ///
80 void emitBasicBlock(MachineBasicBlock &MBB);
81 };
82 }
83
84 char PPCCodeEmitter::ID = 0;
85
86 /// createPPCCodeEmitterPass - Return a pass that emits the collected PPC code
87 /// to the specified MCE object.
createPPCJITCodeEmitterPass(PPCTargetMachine & TM,JITCodeEmitter & JCE)88 FunctionPass *llvm::createPPCJITCodeEmitterPass(PPCTargetMachine &TM,
89 JITCodeEmitter &JCE) {
90 return new PPCCodeEmitter(TM, JCE);
91 }
92
runOnMachineFunction(MachineFunction & MF)93 bool PPCCodeEmitter::runOnMachineFunction(MachineFunction &MF) {
94 assert((MF.getTarget().getRelocationModel() != Reloc::Default ||
95 MF.getTarget().getRelocationModel() != Reloc::Static) &&
96 "JIT relocation model must be set to static or default!");
97
98 MMI = &getAnalysis<MachineModuleInfo>();
99 MCE.setModuleInfo(MMI);
100 do {
101 MovePCtoLROffset = 0;
102 MCE.startFunction(MF);
103 for (MachineFunction::iterator BB = MF.begin(), E = MF.end(); BB != E; ++BB)
104 emitBasicBlock(*BB);
105 } while (MCE.finishFunction(MF));
106
107 return false;
108 }
109
emitBasicBlock(MachineBasicBlock & MBB)110 void PPCCodeEmitter::emitBasicBlock(MachineBasicBlock &MBB) {
111 MCE.StartMachineBasicBlock(&MBB);
112
113 for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E; ++I){
114 const MachineInstr &MI = *I;
115 MCE.processDebugLoc(MI.getDebugLoc(), true);
116 switch (MI.getOpcode()) {
117 default:
118 MCE.emitWordBE(getBinaryCodeForInstr(MI));
119 break;
120 case TargetOpcode::PROLOG_LABEL:
121 case TargetOpcode::EH_LABEL:
122 MCE.emitLabel(MI.getOperand(0).getMCSymbol());
123 break;
124 case TargetOpcode::IMPLICIT_DEF:
125 case TargetOpcode::KILL:
126 break; // pseudo opcode, no side effects
127 case PPC::MovePCtoLR:
128 case PPC::MovePCtoLR8:
129 assert(TM.getRelocationModel() == Reloc::PIC_);
130 MovePCtoLROffset = (void*)MCE.getCurrentPCValue();
131 MCE.emitWordBE(0x48000005); // bl 1
132 break;
133 }
134 MCE.processDebugLoc(MI.getDebugLoc(), false);
135 }
136 }
137
get_crbitm_encoding(const MachineInstr & MI,unsigned OpNo) const138 unsigned PPCCodeEmitter::get_crbitm_encoding(const MachineInstr &MI,
139 unsigned OpNo) const {
140 const MachineOperand &MO = MI.getOperand(OpNo);
141 assert((MI.getOpcode() == PPC::MTCRF || MI.getOpcode() == PPC::MFOCRF) &&
142 (MO.getReg() >= PPC::CR0 && MO.getReg() <= PPC::CR7));
143 return 0x80 >> getPPCRegisterNumbering(MO.getReg());
144 }
145
GetRelocation(const MachineOperand & MO,unsigned RelocID) const146 MachineRelocation PPCCodeEmitter::GetRelocation(const MachineOperand &MO,
147 unsigned RelocID) const {
148 // If in PIC mode, we need to encode the negated address of the
149 // 'movepctolr' into the unrelocated field. After relocation, we'll have
150 // &gv-&movepctolr-4 in the imm field. Once &movepctolr is added to the imm
151 // field, we get &gv. This doesn't happen for branch relocations, which are
152 // always implicitly pc relative.
153 intptr_t Cst = 0;
154 if (TM.getRelocationModel() == Reloc::PIC_) {
155 assert(MovePCtoLROffset && "MovePCtoLR not seen yet?");
156 Cst = -(intptr_t)MovePCtoLROffset - 4;
157 }
158
159 if (MO.isGlobal())
160 return MachineRelocation::getGV(MCE.getCurrentPCOffset(), RelocID,
161 const_cast<GlobalValue *>(MO.getGlobal()),
162 Cst, isa<Function>(MO.getGlobal()));
163 if (MO.isSymbol())
164 return MachineRelocation::getExtSym(MCE.getCurrentPCOffset(),
165 RelocID, MO.getSymbolName(), Cst);
166 if (MO.isCPI())
167 return MachineRelocation::getConstPool(MCE.getCurrentPCOffset(),
168 RelocID, MO.getIndex(), Cst);
169
170 if (MO.isMBB())
171 return MachineRelocation::getBB(MCE.getCurrentPCOffset(),
172 RelocID, MO.getMBB());
173
174 assert(MO.isJTI());
175 return MachineRelocation::getJumpTable(MCE.getCurrentPCOffset(),
176 RelocID, MO.getIndex(), Cst);
177 }
178
getDirectBrEncoding(const MachineInstr & MI,unsigned OpNo) const179 unsigned PPCCodeEmitter::getDirectBrEncoding(const MachineInstr &MI,
180 unsigned OpNo) const {
181 const MachineOperand &MO = MI.getOperand(OpNo);
182 if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
183
184 MCE.addRelocation(GetRelocation(MO, PPC::reloc_pcrel_bx));
185 return 0;
186 }
187
getCondBrEncoding(const MachineInstr & MI,unsigned OpNo) const188 unsigned PPCCodeEmitter::getCondBrEncoding(const MachineInstr &MI,
189 unsigned OpNo) const {
190 const MachineOperand &MO = MI.getOperand(OpNo);
191 MCE.addRelocation(GetRelocation(MO, PPC::reloc_pcrel_bcx));
192 return 0;
193 }
194
getHA16Encoding(const MachineInstr & MI,unsigned OpNo) const195 unsigned PPCCodeEmitter::getHA16Encoding(const MachineInstr &MI,
196 unsigned OpNo) const {
197 const MachineOperand &MO = MI.getOperand(OpNo);
198 if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
199
200 MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_high));
201 return 0;
202 }
203
getLO16Encoding(const MachineInstr & MI,unsigned OpNo) const204 unsigned PPCCodeEmitter::getLO16Encoding(const MachineInstr &MI,
205 unsigned OpNo) const {
206 const MachineOperand &MO = MI.getOperand(OpNo);
207 if (MO.isReg() || MO.isImm()) return getMachineOpValue(MI, MO);
208
209 MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low));
210 return 0;
211 }
212
getMemRIEncoding(const MachineInstr & MI,unsigned OpNo) const213 unsigned PPCCodeEmitter::getMemRIEncoding(const MachineInstr &MI,
214 unsigned OpNo) const {
215 // Encode (imm, reg) as a memri, which has the low 16-bits as the
216 // displacement and the next 5 bits as the register #.
217 assert(MI.getOperand(OpNo+1).isReg());
218 unsigned RegBits = getMachineOpValue(MI, MI.getOperand(OpNo+1)) << 16;
219
220 const MachineOperand &MO = MI.getOperand(OpNo);
221 if (MO.isImm())
222 return (getMachineOpValue(MI, MO) & 0xFFFF) | RegBits;
223
224 // Add a fixup for the displacement field.
225 MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low));
226 return RegBits;
227 }
228
getMemRIXEncoding(const MachineInstr & MI,unsigned OpNo) const229 unsigned PPCCodeEmitter::getMemRIXEncoding(const MachineInstr &MI,
230 unsigned OpNo) const {
231 // Encode (imm, reg) as a memrix, which has the low 14-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)) << 14;
235
236 const MachineOperand &MO = MI.getOperand(OpNo);
237 if (MO.isImm())
238 return (getMachineOpValue(MI, MO) & 0x3FFF) | RegBits;
239
240 MCE.addRelocation(GetRelocation(MO, PPC::reloc_absolute_low_ix));
241 return RegBits;
242 }
243
244
getMachineOpValue(const MachineInstr & MI,const MachineOperand & MO) const245 unsigned PPCCodeEmitter::getMachineOpValue(const MachineInstr &MI,
246 const MachineOperand &MO) const {
247
248 if (MO.isReg()) {
249 // MTCRF/MFOCRF should go through get_crbitm_encoding for the CR operand.
250 // The GPR operand should come through here though.
251 assert((MI.getOpcode() != PPC::MTCRF && MI.getOpcode() != PPC::MFOCRF) ||
252 MO.getReg() < PPC::CR0 || MO.getReg() > PPC::CR7);
253 return getPPCRegisterNumbering(MO.getReg());
254 }
255
256 assert(MO.isImm() &&
257 "Relocation required in an instruction that we cannot encode!");
258 return MO.getImm();
259 }
260
261 #include "PPCGenCodeEmitter.inc"
262