--- /dev/null
+//===- lib/MC/MCObjectDisassembler.cpp ------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/MC/MCObjectDisassembler.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
+#include "llvm/MC/MCAnalysis/MCAtom.h"
+#include "llvm/MC/MCAnalysis/MCFunction.h"
+#include "llvm/MC/MCAnalysis/MCModule.h"
+#include "llvm/MC/MCAnalysis/MCObjectSymbolizer.h"
+#include "llvm/MC/MCDisassembler.h"
+#include "llvm/MC/MCInstrAnalysis.h"
+#include "llvm/Object/MachO.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/MachO.h"
+#include "llvm/Support/MemoryObject.h"
+#include "llvm/Support/StringRefMemoryObject.h"
+#include "llvm/Support/raw_ostream.h"
+#include <map>
+
+using namespace llvm;
+using namespace object;
+
+#define DEBUG_TYPE "mc"
+
+MCObjectDisassembler::MCObjectDisassembler(const ObjectFile &Obj,
+ const MCDisassembler &Dis,
+ const MCInstrAnalysis &MIA)
+ : Obj(Obj), Dis(Dis), MIA(MIA), MOS(nullptr) {}
+
+uint64_t MCObjectDisassembler::getEntrypoint() {
+ for (const SymbolRef &Symbol : Obj.symbols()) {
+ StringRef Name;
+ Symbol.getName(Name);
+ if (Name == "main" || Name == "_main") {
+ uint64_t Entrypoint;
+ Symbol.getAddress(Entrypoint);
+ return getEffectiveLoadAddr(Entrypoint);
+ }
+ }
+ return 0;
+}
+
+ArrayRef<uint64_t> MCObjectDisassembler::getStaticInitFunctions() {
+ return ArrayRef<uint64_t>();
+}
+
+ArrayRef<uint64_t> MCObjectDisassembler::getStaticExitFunctions() {
+ return ArrayRef<uint64_t>();
+}
+
+MemoryObject *MCObjectDisassembler::getRegionFor(uint64_t Addr) {
+ // FIXME: Keep track of object sections.
+ return FallbackRegion.get();
+}
+
+uint64_t MCObjectDisassembler::getEffectiveLoadAddr(uint64_t Addr) {
+ return Addr;
+}
+
+uint64_t MCObjectDisassembler::getOriginalLoadAddr(uint64_t Addr) {
+ return Addr;
+}
+
+MCModule *MCObjectDisassembler::buildEmptyModule() {
+ MCModule *Module = new MCModule;
+ Module->Entrypoint = getEntrypoint();
+ return Module;
+}
+
+MCModule *MCObjectDisassembler::buildModule(bool withCFG) {
+ MCModule *Module = buildEmptyModule();
+
+ buildSectionAtoms(Module);
+ if (withCFG)
+ buildCFG(Module);
+ return Module;
+}
+
+void MCObjectDisassembler::buildSectionAtoms(MCModule *Module) {
+ for (const SectionRef &Section : Obj.sections()) {
+ bool isText;
+ Section.isText(isText);
+ bool isData;
+ Section.isData(isData);
+ if (!isData && !isText)
+ continue;
+
+ uint64_t StartAddr;
+ Section.getAddress(StartAddr);
+ uint64_t SecSize;
+ Section.getSize(SecSize);
+ if (StartAddr == UnknownAddressOrSize || SecSize == UnknownAddressOrSize)
+ continue;
+ StartAddr = getEffectiveLoadAddr(StartAddr);
+
+ StringRef Contents;
+ Section.getContents(Contents);
+ StringRefMemoryObject memoryObject(Contents, StartAddr);
+
+ // We don't care about things like non-file-backed sections yet.
+ if (Contents.size() != SecSize || !SecSize)
+ continue;
+ uint64_t EndAddr = StartAddr + SecSize - 1;
+
+ StringRef SecName;
+ Section.getName(SecName);
+
+ if (isText) {
+ MCTextAtom *Text = nullptr;
+ MCDataAtom *InvalidData = nullptr;
+
+ uint64_t InstSize;
+ for (uint64_t Index = 0; Index < SecSize; Index += InstSize) {
+ const uint64_t CurAddr = StartAddr + Index;
+ MCInst Inst;
+ if (Dis.getInstruction(Inst, InstSize, memoryObject, CurAddr, nulls(),
+ nulls())) {
+ if (!Text) {
+ Text = Module->createTextAtom(CurAddr, CurAddr);
+ Text->setName(SecName);
+ }
+ Text->addInst(Inst, InstSize);
+ InvalidData = nullptr;
+ } else {
+ assert(InstSize && "getInstruction() consumed no bytes");
+ if (!InvalidData) {
+ Text = nullptr;
+ InvalidData = Module->createDataAtom(CurAddr, CurAddr+InstSize - 1);
+ }
+ for (uint64_t I = 0; I < InstSize; ++I)
+ InvalidData->addData(Contents[Index+I]);
+ }
+ }
+ } else {
+ MCDataAtom *Data = Module->createDataAtom(StartAddr, EndAddr);
+ Data->setName(SecName);
+ for (uint64_t Index = 0; Index < SecSize; ++Index)
+ Data->addData(Contents[Index]);
+ }
+ }
+}
+
+namespace {
+ struct BBInfo;
+ typedef SmallPtrSet<BBInfo*, 2> BBInfoSetTy;
+
+ struct BBInfo {
+ MCTextAtom *Atom;
+ MCBasicBlock *BB;
+ BBInfoSetTy Succs;
+ BBInfoSetTy Preds;
+ MCObjectDisassembler::AddressSetTy SuccAddrs;
+
+ BBInfo() : Atom(nullptr), BB(nullptr) {}
+
+ void addSucc(BBInfo &Succ) {
+ Succs.insert(&Succ);
+ Succ.Preds.insert(this);
+ }
+ };
+}
+
+static void RemoveDupsFromAddressVector(MCObjectDisassembler::AddressSetTy &V) {
+ std::sort(V.begin(), V.end());
+ V.erase(std::unique(V.begin(), V.end()), V.end());
+}
+
+void MCObjectDisassembler::buildCFG(MCModule *Module) {
+ typedef std::map<uint64_t, BBInfo> BBInfoByAddrTy;
+ BBInfoByAddrTy BBInfos;
+ AddressSetTy Splits;
+ AddressSetTy Calls;
+
+ for (const SymbolRef &Symbol : Obj.symbols()) {
+ SymbolRef::Type SymType;
+ Symbol.getType(SymType);
+ if (SymType == SymbolRef::ST_Function) {
+ uint64_t SymAddr;
+ Symbol.getAddress(SymAddr);
+ SymAddr = getEffectiveLoadAddr(SymAddr);
+ Calls.push_back(SymAddr);
+ Splits.push_back(SymAddr);
+ }
+ }
+
+ assert(Module->func_begin() == Module->func_end()
+ && "Module already has a CFG!");
+
+ // First, determine the basic block boundaries and call targets.
+ for (MCModule::atom_iterator AI = Module->atom_begin(),
+ AE = Module->atom_end();
+ AI != AE; ++AI) {
+ MCTextAtom *TA = dyn_cast<MCTextAtom>(*AI);
+ if (!TA) continue;
+ Calls.push_back(TA->getBeginAddr());
+ BBInfos[TA->getBeginAddr()].Atom = TA;
+ for (MCTextAtom::const_iterator II = TA->begin(), IE = TA->end();
+ II != IE; ++II) {
+ if (MIA.isTerminator(II->Inst))
+ Splits.push_back(II->Address + II->Size);
+ uint64_t Target;
+ if (MIA.evaluateBranch(II->Inst, II->Address, II->Size, Target)) {
+ if (MIA.isCall(II->Inst))
+ Calls.push_back(Target);
+ Splits.push_back(Target);
+ }
+ }
+ }
+
+ RemoveDupsFromAddressVector(Splits);
+ RemoveDupsFromAddressVector(Calls);
+
+ // Split text atoms into basic block atoms.
+ for (AddressSetTy::const_iterator SI = Splits.begin(), SE = Splits.end();
+ SI != SE; ++SI) {
+ MCAtom *A = Module->findAtomContaining(*SI);
+ if (!A) continue;
+ MCTextAtom *TA = cast<MCTextAtom>(A);
+ if (TA->getBeginAddr() == *SI)
+ continue;
+ MCTextAtom *NewAtom = TA->split(*SI);
+ BBInfos[NewAtom->getBeginAddr()].Atom = NewAtom;
+ StringRef BBName = TA->getName();
+ BBName = BBName.substr(0, BBName.find_last_of(':'));
+ NewAtom->setName((BBName + ":" + utohexstr(*SI)).str());
+ }
+
+ // Compute succs/preds.
+ for (MCModule::atom_iterator AI = Module->atom_begin(),
+ AE = Module->atom_end();
+ AI != AE; ++AI) {
+ MCTextAtom *TA = dyn_cast<MCTextAtom>(*AI);
+ if (!TA) continue;
+ BBInfo &CurBB = BBInfos[TA->getBeginAddr()];
+ const MCDecodedInst &LI = TA->back();
+ if (MIA.isBranch(LI.Inst)) {
+ uint64_t Target;
+ if (MIA.evaluateBranch(LI.Inst, LI.Address, LI.Size, Target))
+ CurBB.addSucc(BBInfos[Target]);
+ if (MIA.isConditionalBranch(LI.Inst))
+ CurBB.addSucc(BBInfos[LI.Address + LI.Size]);
+ } else if (!MIA.isTerminator(LI.Inst))
+ CurBB.addSucc(BBInfos[LI.Address + LI.Size]);
+ }
+
+
+ // Create functions and basic blocks.
+ for (AddressSetTy::const_iterator CI = Calls.begin(), CE = Calls.end();
+ CI != CE; ++CI) {
+ BBInfo &BBI = BBInfos[*CI];
+ if (!BBI.Atom) continue;
+
+ MCFunction &MCFN = *Module->createFunction(BBI.Atom->getName());
+
+ // Create MCBBs.
+ SmallSetVector<BBInfo*, 16> Worklist;
+ Worklist.insert(&BBI);
+ for (size_t wi = 0; wi < Worklist.size(); ++wi) {
+ BBInfo *BBI = Worklist[wi];
+ if (!BBI->Atom)
+ continue;
+ BBI->BB = &MCFN.createBlock(*BBI->Atom);
+ // Add all predecessors and successors to the worklist.
+ for (BBInfoSetTy::iterator SI = BBI->Succs.begin(), SE = BBI->Succs.end();
+ SI != SE; ++SI)
+ Worklist.insert(*SI);
+ for (BBInfoSetTy::iterator PI = BBI->Preds.begin(), PE = BBI->Preds.end();
+ PI != PE; ++PI)
+ Worklist.insert(*PI);
+ }
+
+ // Set preds/succs.
+ for (size_t wi = 0; wi < Worklist.size(); ++wi) {
+ BBInfo *BBI = Worklist[wi];
+ MCBasicBlock *MCBB = BBI->BB;
+ if (!MCBB)
+ continue;
+ for (BBInfoSetTy::iterator SI = BBI->Succs.begin(), SE = BBI->Succs.end();
+ SI != SE; ++SI)
+ if ((*SI)->BB)
+ MCBB->addSuccessor((*SI)->BB);
+ for (BBInfoSetTy::iterator PI = BBI->Preds.begin(), PE = BBI->Preds.end();
+ PI != PE; ++PI)
+ if ((*PI)->BB)
+ MCBB->addPredecessor((*PI)->BB);
+ }
+ }
+}
+
+// Basic idea of the disassembly + discovery:
+//
+// start with the wanted address, insert it in the worklist
+// while worklist not empty, take next address in the worklist:
+// - check if atom exists there
+// - if middle of atom:
+// - split basic blocks referencing the atom
+// - look for an already encountered BBInfo (using a map<atom, bbinfo>)
+// - if there is, split it (new one, fallthrough, move succs, etc..)
+// - if start of atom: nothing else to do
+// - if no atom: create new atom and new bbinfo
+// - look at the last instruction in the atom, add succs to worklist
+// for all elements in the worklist:
+// - create basic block, update preds/succs, etc..
+//
+MCBasicBlock *MCObjectDisassembler::getBBAt(MCModule *Module, MCFunction *MCFN,
+ uint64_t BBBeginAddr,
+ AddressSetTy &CallTargets,
+ AddressSetTy &TailCallTargets) {
+ typedef std::map<uint64_t, BBInfo> BBInfoByAddrTy;
+ typedef SmallSetVector<uint64_t, 16> AddrWorklistTy;
+ BBInfoByAddrTy BBInfos;
+ AddrWorklistTy Worklist;
+
+ Worklist.insert(BBBeginAddr);
+ for (size_t wi = 0; wi < Worklist.size(); ++wi) {
+ const uint64_t BeginAddr = Worklist[wi];
+ BBInfo *BBI = &BBInfos[BeginAddr];
+
+ MCTextAtom *&TA = BBI->Atom;
+ assert(!TA && "Discovered basic block already has an associated atom!");
+
+ // Look for an atom at BeginAddr.
+ if (MCAtom *A = Module->findAtomContaining(BeginAddr)) {
+ // FIXME: We don't care about mixed atoms, see above.
+ TA = cast<MCTextAtom>(A);
+
+ // The found atom doesn't begin at BeginAddr, we have to split it.
+ if (TA->getBeginAddr() != BeginAddr) {
+ // FIXME: Handle overlapping atoms: middle-starting instructions, etc..
+ MCTextAtom *NewTA = TA->split(BeginAddr);
+
+ // Look for an already encountered basic block that needs splitting
+ BBInfoByAddrTy::iterator It = BBInfos.find(TA->getBeginAddr());
+ if (It != BBInfos.end() && It->second.Atom) {
+ BBI->SuccAddrs = It->second.SuccAddrs;
+ It->second.SuccAddrs.clear();
+ It->second.SuccAddrs.push_back(BeginAddr);
+ }
+ TA = NewTA;
+ }
+ BBI->Atom = TA;
+ } else {
+ // If we didn't find an atom, then we have to disassemble to create one!
+
+ MemoryObject *Region = getRegionFor(BeginAddr);
+ if (!Region)
+ llvm_unreachable(("Couldn't find suitable region for disassembly at " +
+ utostr(BeginAddr)).c_str());
+
+ uint64_t InstSize;
+ uint64_t EndAddr = Region->getBase() + Region->getExtent();
+
+ // We want to stop before the next atom and have a fallthrough to it.
+ if (MCTextAtom *NextAtom =
+ cast_or_null<MCTextAtom>(Module->findFirstAtomAfter(BeginAddr)))
+ EndAddr = std::min(EndAddr, NextAtom->getBeginAddr());
+
+ for (uint64_t Addr = BeginAddr; Addr < EndAddr; Addr += InstSize) {
+ MCInst Inst;
+ if (Dis.getInstruction(Inst, InstSize, *Region, Addr, nulls(),
+ nulls())) {
+ if (!TA)
+ TA = Module->createTextAtom(Addr, Addr);
+ TA->addInst(Inst, InstSize);
+ } else {
+ // We don't care about splitting mixed atoms either.
+ llvm_unreachable("Couldn't disassemble instruction in atom.");
+ }
+
+ uint64_t BranchTarget;
+ if (MIA.evaluateBranch(Inst, Addr, InstSize, BranchTarget)) {
+ if (MIA.isCall(Inst))
+ CallTargets.push_back(BranchTarget);
+ }
+
+ if (MIA.isTerminator(Inst))
+ break;
+ }
+ BBI->Atom = TA;
+ }
+
+ assert(TA && "Couldn't disassemble atom, none was created!");
+ assert(TA->begin() != TA->end() && "Empty atom!");
+
+ MemoryObject *Region = getRegionFor(TA->getBeginAddr());
+ assert(Region && "Couldn't find region for already disassembled code!");
+ uint64_t EndRegion = Region->getBase() + Region->getExtent();
+
+ // Now we have a basic block atom, add successors.
+ // Add the fallthrough block.
+ if ((MIA.isConditionalBranch(TA->back().Inst) ||
+ !MIA.isTerminator(TA->back().Inst)) &&
+ (TA->getEndAddr() + 1 < EndRegion)) {
+ BBI->SuccAddrs.push_back(TA->getEndAddr() + 1);
+ Worklist.insert(TA->getEndAddr() + 1);
+ }
+
+ // If the terminator is a branch, add the target block.
+ if (MIA.isBranch(TA->back().Inst)) {
+ uint64_t BranchTarget;
+ if (MIA.evaluateBranch(TA->back().Inst, TA->back().Address,
+ TA->back().Size, BranchTarget)) {
+ StringRef ExtFnName;
+ if (MOS)
+ ExtFnName =
+ MOS->findExternalFunctionAt(getOriginalLoadAddr(BranchTarget));
+ if (!ExtFnName.empty()) {
+ TailCallTargets.push_back(BranchTarget);
+ CallTargets.push_back(BranchTarget);
+ } else {
+ BBI->SuccAddrs.push_back(BranchTarget);
+ Worklist.insert(BranchTarget);
+ }
+ }
+ }
+ }
+
+ for (size_t wi = 0, we = Worklist.size(); wi != we; ++wi) {
+ const uint64_t BeginAddr = Worklist[wi];
+ BBInfo *BBI = &BBInfos[BeginAddr];
+
+ assert(BBI->Atom && "Found a basic block without an associated atom!");
+
+ // Look for a basic block at BeginAddr.
+ BBI->BB = MCFN->find(BeginAddr);
+ if (BBI->BB) {
+ // FIXME: check that the succs/preds are the same
+ continue;
+ }
+ // If there was none, we have to create one from the atom.
+ BBI->BB = &MCFN->createBlock(*BBI->Atom);
+ }
+
+ for (size_t wi = 0, we = Worklist.size(); wi != we; ++wi) {
+ const uint64_t BeginAddr = Worklist[wi];
+ BBInfo *BBI = &BBInfos[BeginAddr];
+ MCBasicBlock *BB = BBI->BB;
+
+ RemoveDupsFromAddressVector(BBI->SuccAddrs);
+ for (AddressSetTy::const_iterator SI = BBI->SuccAddrs.begin(),
+ SE = BBI->SuccAddrs.end();
+ SI != SE; ++SI) {
+ MCBasicBlock *Succ = BBInfos[*SI].BB;
+ BB->addSuccessor(Succ);
+ Succ->addPredecessor(BB);
+ }
+ }
+
+ assert(BBInfos[Worklist[0]].BB &&
+ "No basic block created at requested address?");
+
+ return BBInfos[Worklist[0]].BB;
+}
+
+MCFunction *
+MCObjectDisassembler::createFunction(MCModule *Module, uint64_t BeginAddr,
+ AddressSetTy &CallTargets,
+ AddressSetTy &TailCallTargets) {
+ // First, check if this is an external function.
+ StringRef ExtFnName;
+ if (MOS)
+ ExtFnName = MOS->findExternalFunctionAt(getOriginalLoadAddr(BeginAddr));
+ if (!ExtFnName.empty())
+ return Module->createFunction(ExtFnName);
+
+ // If it's not, look for an existing function.
+ for (MCModule::func_iterator FI = Module->func_begin(),
+ FE = Module->func_end();
+ FI != FE; ++FI) {
+ if ((*FI)->empty())
+ continue;
+ // FIXME: MCModule should provide a findFunctionByAddr()
+ if ((*FI)->getEntryBlock()->getInsts()->getBeginAddr() == BeginAddr)
+ return FI->get();
+ }
+
+ // Finally, just create a new one.
+ MCFunction *MCFN = Module->createFunction("");
+ getBBAt(Module, MCFN, BeginAddr, CallTargets, TailCallTargets);
+ return MCFN;
+}
+
+// MachO MCObjectDisassembler implementation.
+
+MCMachOObjectDisassembler::MCMachOObjectDisassembler(
+ const MachOObjectFile &MOOF, const MCDisassembler &Dis,
+ const MCInstrAnalysis &MIA, uint64_t VMAddrSlide,
+ uint64_t HeaderLoadAddress)
+ : MCObjectDisassembler(MOOF, Dis, MIA), MOOF(MOOF),
+ VMAddrSlide(VMAddrSlide), HeaderLoadAddress(HeaderLoadAddress) {
+
+ for (const SectionRef &Section : MOOF.sections()) {
+ StringRef Name;
+ Section.getName(Name);
+ // FIXME: We should use the S_ section type instead of the name.
+ if (Name == "__mod_init_func") {
+ DEBUG(dbgs() << "Found __mod_init_func section!\n");
+ Section.getContents(ModInitContents);
+ } else if (Name == "__mod_exit_func") {
+ DEBUG(dbgs() << "Found __mod_exit_func section!\n");
+ Section.getContents(ModExitContents);
+ }
+ }
+}
+
+// FIXME: Only do the translations for addresses actually inside the object.
+uint64_t MCMachOObjectDisassembler::getEffectiveLoadAddr(uint64_t Addr) {
+ return Addr + VMAddrSlide;
+}
+
+uint64_t
+MCMachOObjectDisassembler::getOriginalLoadAddr(uint64_t EffectiveAddr) {
+ return EffectiveAddr - VMAddrSlide;
+}
+
+uint64_t MCMachOObjectDisassembler::getEntrypoint() {
+ uint64_t EntryFileOffset = 0;
+
+ // Look for LC_MAIN.
+ {
+ uint32_t LoadCommandCount = MOOF.getHeader().ncmds;
+ MachOObjectFile::LoadCommandInfo Load = MOOF.getFirstLoadCommandInfo();
+ for (unsigned I = 0;; ++I) {
+ if (Load.C.cmd == MachO::LC_MAIN) {
+ EntryFileOffset =
+ ((const MachO::entry_point_command *)Load.Ptr)->entryoff;
+ break;
+ }
+
+ if (I == LoadCommandCount - 1)
+ break;
+ else
+ Load = MOOF.getNextLoadCommandInfo(Load);
+ }
+ }
+
+ // If we didn't find anything, default to the common implementation.
+ // FIXME: Maybe we could also look at LC_UNIXTHREAD and friends?
+ if (EntryFileOffset)
+ return MCObjectDisassembler::getEntrypoint();
+
+ return EntryFileOffset + HeaderLoadAddress;
+}
+
+ArrayRef<uint64_t> MCMachOObjectDisassembler::getStaticInitFunctions() {
+ // FIXME: We only handle 64bit mach-o
+ assert(MOOF.is64Bit());
+
+ size_t EntrySize = 8;
+ size_t EntryCount = ModInitContents.size() / EntrySize;
+ return ArrayRef<uint64_t>(
+ reinterpret_cast<const uint64_t *>(ModInitContents.data()), EntryCount);
+}
+
+ArrayRef<uint64_t> MCMachOObjectDisassembler::getStaticExitFunctions() {
+ // FIXME: We only handle 64bit mach-o
+ assert(MOOF.is64Bit());
+
+ size_t EntrySize = 8;
+ size_t EntryCount = ModExitContents.size() / EntrySize;
+ return ArrayRef<uint64_t>(
+ reinterpret_cast<const uint64_t *>(ModExitContents.data()), EntryCount);
+}
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