1 //===- lib/MC/MCObjectDisassembler.cpp ------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/MC/MCObjectDisassembler.h"
11 #include "llvm/ADT/STLExtras.h"
12 #include "llvm/ADT/SetVector.h"
13 #include "llvm/ADT/StringExtras.h"
14 #include "llvm/ADT/StringRef.h"
15 #include "llvm/ADT/Twine.h"
16 #include "llvm/MC/MCAtom.h"
17 #include "llvm/MC/MCDisassembler.h"
18 #include "llvm/MC/MCFunction.h"
19 #include "llvm/MC/MCInstrAnalysis.h"
20 #include "llvm/MC/MCModule.h"
21 #include "llvm/Object/ObjectFile.h"
22 #include "llvm/Support/MemoryObject.h"
23 #include "llvm/Support/StringRefMemoryObject.h"
24 #include "llvm/Support/raw_ostream.h"
29 using namespace object;
31 MCObjectDisassembler::MCObjectDisassembler(const ObjectFile &Obj,
32 const MCDisassembler &Dis,
33 const MCInstrAnalysis &MIA)
34 : Obj(Obj), Dis(Dis), MIA(MIA) {}
36 uint64_t MCObjectDisassembler::getEntrypoint() {
38 for (symbol_iterator SI = Obj.begin_symbols(), SE = Obj.end_symbols();
39 SI != SE; SI.increment(ec)) {
44 if (Name == "main" || Name == "_main") {
46 SI->getAddress(Entrypoint);
53 ArrayRef<uint64_t> MCObjectDisassembler::getStaticInitFunctions() {
54 return ArrayRef<uint64_t>();
57 ArrayRef<uint64_t> MCObjectDisassembler::getStaticExitFunctions() {
58 return ArrayRef<uint64_t>();
61 MCModule *MCObjectDisassembler::buildEmptyModule() {
62 MCModule *Module = new MCModule;
63 Module->Entrypoint = getEntrypoint();
67 MCModule *MCObjectDisassembler::buildModule(bool withCFG) {
68 MCModule *Module = buildEmptyModule();
70 buildSectionAtoms(Module);
76 void MCObjectDisassembler::buildSectionAtoms(MCModule *Module) {
78 for (section_iterator SI = Obj.begin_sections(),
79 SE = Obj.end_sections();
84 bool isText; SI->isText(isText);
85 bool isData; SI->isData(isData);
86 if (!isData && !isText)
89 uint64_t StartAddr; SI->getAddress(StartAddr);
90 uint64_t SecSize; SI->getSize(SecSize);
91 if (StartAddr == UnknownAddressOrSize || SecSize == UnknownAddressOrSize)
94 StringRef Contents; SI->getContents(Contents);
95 StringRefMemoryObject memoryObject(Contents, StartAddr);
97 // We don't care about things like non-file-backed sections yet.
98 if (Contents.size() != SecSize || !SecSize)
100 uint64_t EndAddr = StartAddr + SecSize - 1;
102 StringRef SecName; SI->getName(SecName);
105 MCTextAtom *Text = Module->createTextAtom(StartAddr, EndAddr);
106 Text->setName(SecName);
108 for (uint64_t Index = 0; Index < SecSize; Index += InstSize) {
110 if (Dis.getInstruction(Inst, InstSize, memoryObject, Index,
112 Text->addInst(Inst, InstSize);
114 // We don't care about splitting mixed atoms either.
115 llvm_unreachable("Couldn't disassemble instruction in atom.");
119 MCDataAtom *Data = Module->createDataAtom(StartAddr, EndAddr);
120 Data->setName(SecName);
121 for (uint64_t Index = 0; Index < SecSize; ++Index)
122 Data->addData(Contents[Index]);
129 typedef std::set<BBInfo*> BBInfoSetTy;
137 void addSucc(BBInfo &Succ) {
139 Succ.Preds.insert(this);
144 void MCObjectDisassembler::buildCFG(MCModule *Module) {
145 typedef std::map<uint64_t, BBInfo> BBInfoByAddrTy;
146 BBInfoByAddrTy BBInfos;
147 typedef std::set<uint64_t> AddressSetTy;
152 for (symbol_iterator SI = Obj.begin_symbols(), SE = Obj.end_symbols();
153 SI != SE; SI.increment(ec)) {
156 SymbolRef::Type SymType;
157 SI->getType(SymType);
158 if (SymType == SymbolRef::ST_Function) {
160 SI->getAddress(SymAddr);
161 Calls.insert(SymAddr);
162 Splits.insert(SymAddr);
166 assert(Module->func_begin() == Module->func_end()
167 && "Module already has a CFG!");
169 // First, determine the basic block boundaries and call targets.
170 for (MCModule::atom_iterator AI = Module->atom_begin(),
171 AE = Module->atom_end();
173 MCTextAtom *TA = dyn_cast<MCTextAtom>(*AI);
175 Calls.insert(TA->getBeginAddr());
176 BBInfos[TA->getBeginAddr()].Atom = TA;
177 for (MCTextAtom::const_iterator II = TA->begin(), IE = TA->end();
179 if (MIA.isTerminator(II->Inst))
180 Splits.insert(II->Address + II->Size);
182 if (MIA.evaluateBranch(II->Inst, II->Address, II->Size, Target)) {
183 if (MIA.isCall(II->Inst))
184 Calls.insert(Target);
185 Splits.insert(Target);
190 // Split text atoms into basic block atoms.
191 for (AddressSetTy::const_iterator SI = Splits.begin(), SE = Splits.end();
193 MCAtom *A = Module->findAtomContaining(*SI);
195 MCTextAtom *TA = cast<MCTextAtom>(A);
196 if (TA->getBeginAddr() == *SI)
198 MCTextAtom *NewAtom = TA->split(*SI);
199 BBInfos[NewAtom->getBeginAddr()].Atom = NewAtom;
200 StringRef BBName = TA->getName();
201 BBName = BBName.substr(0, BBName.find_last_of(':'));
202 NewAtom->setName((BBName + ":" + utohexstr(*SI)).str());
205 // Compute succs/preds.
206 for (MCModule::atom_iterator AI = Module->atom_begin(),
207 AE = Module->atom_end();
209 MCTextAtom *TA = dyn_cast<MCTextAtom>(*AI);
211 BBInfo &CurBB = BBInfos[TA->getBeginAddr()];
212 const MCDecodedInst &LI = TA->back();
213 if (MIA.isBranch(LI.Inst)) {
215 if (MIA.evaluateBranch(LI.Inst, LI.Address, LI.Size, Target))
216 CurBB.addSucc(BBInfos[Target]);
217 if (MIA.isConditionalBranch(LI.Inst))
218 CurBB.addSucc(BBInfos[LI.Address + LI.Size]);
219 } else if (!MIA.isTerminator(LI.Inst))
220 CurBB.addSucc(BBInfos[LI.Address + LI.Size]);
224 // Create functions and basic blocks.
225 for (AddressSetTy::const_iterator CI = Calls.begin(), CE = Calls.end();
227 BBInfo &BBI = BBInfos[*CI];
228 if (!BBI.Atom) continue;
230 MCFunction &MCFN = *Module->createFunction(BBI.Atom->getName());
233 SmallSetVector<BBInfo*, 16> Worklist;
234 Worklist.insert(&BBI);
235 for (size_t WI = 0; WI < Worklist.size(); ++WI) {
236 BBInfo *BBI = Worklist[WI];
239 BBI->BB = &MCFN.createBlock(*BBI->Atom);
240 // Add all predecessors and successors to the worklist.
241 for (BBInfoSetTy::iterator SI = BBI->Succs.begin(), SE = BBI->Succs.end();
243 Worklist.insert(*SI);
244 for (BBInfoSetTy::iterator PI = BBI->Preds.begin(), PE = BBI->Preds.end();
246 Worklist.insert(*PI);
250 for (size_t WI = 0; WI < Worklist.size(); ++WI) {
251 BBInfo *BBI = Worklist[WI];
252 MCBasicBlock *MCBB = BBI->BB;
255 for (BBInfoSetTy::iterator SI = BBI->Succs.begin(), SE = BBI->Succs.end();
257 MCBB->addSuccessor((*SI)->BB);
258 for (BBInfoSetTy::iterator PI = BBI->Preds.begin(), PE = BBI->Preds.end();
260 MCBB->addPredecessor((*PI)->BB);