X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FMC%2FMCObjectDisassembler.cpp;h=16a110f09bf8559154a1d9974614d502c8c1a6af;hb=6079f00035e029f12e4be0281aa2cbfbb4817141;hp=1ea6eed3078046f7fe408a434e5a2503a38761fa;hpb=7ab184a2a1cbf5b5b340d663e07550659438ed7c;p=oota-llvm.git

diff --git a/lib/MC/MCObjectDisassembler.cpp b/lib/MC/MCObjectDisassembler.cpp
index 1ea6eed3078..16a110f09bf 100644
--- a/lib/MC/MCObjectDisassembler.cpp
+++ b/lib/MC/MCObjectDisassembler.cpp
@@ -8,8 +8,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/MC/MCObjectDisassembler.h"
-#include "llvm/ADT/STLExtras.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"
@@ -18,12 +18,15 @@
 #include "llvm/MC/MCFunction.h"
 #include "llvm/MC/MCInstrAnalysis.h"
 #include "llvm/MC/MCModule.h"
+#include "llvm/MC/MCObjectSymbolizer.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>
-#include <set>
 
 using namespace llvm;
 using namespace object;
@@ -31,10 +34,55 @@ using namespace object;
 MCObjectDisassembler::MCObjectDisassembler(const ObjectFile &Obj,
                                            const MCDisassembler &Dis,
                                            const MCInstrAnalysis &MIA)
-  : Obj(Obj), Dis(Dis), MIA(MIA) {}
+    : Obj(Obj), Dis(Dis), MIA(MIA), MOS(0) {}
 
-MCModule *MCObjectDisassembler::buildModule(bool withCFG) {
+uint64_t MCObjectDisassembler::getEntrypoint() {
+  error_code ec;
+  for (symbol_iterator SI = Obj.begin_symbols(), SE = Obj.end_symbols();
+       SI != SE; SI.increment(ec)) {
+    if (ec)
+      break;
+    StringRef Name;
+    SI->getName(Name);
+    if (Name == "main" || Name == "_main") {
+      uint64_t Entrypoint;
+      SI->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);
@@ -58,9 +106,10 @@ void MCObjectDisassembler::buildSectionAtoms(MCModule *Module) {
     uint64_t SecSize; SI->getSize(SecSize);
     if (StartAddr == UnknownAddressOrSize || SecSize == UnknownAddressOrSize)
       continue;
+    StartAddr = getEffectiveLoadAddr(StartAddr);
 
     StringRef Contents; SI->getContents(Contents);
-    StringRefMemoryObject memoryObject(Contents);
+    StringRefMemoryObject memoryObject(Contents, StartAddr);
 
     // We don't care about things like non-file-backed sections yet.
     if (Contents.size() != SecSize || !SecSize)
@@ -70,19 +119,31 @@ void MCObjectDisassembler::buildSectionAtoms(MCModule *Module) {
     StringRef SecName; SI->getName(SecName);
 
     if (isText) {
-      MCTextAtom *Text = Module->createTextAtom(StartAddr, EndAddr);
-      Text->setName(SecName);
+      MCTextAtom *Text = 0;
+      MCDataAtom *InvalidData = 0;
+
       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, Index,
-                               nulls(), nulls()))
+        if (Dis.getInstruction(Inst, InstSize, memoryObject, CurAddr, nulls(),
+                               nulls())) {
+          if (!Text) {
+            Text = Module->createTextAtom(CurAddr, CurAddr);
+            Text->setName(SecName);
+          }
           Text->addInst(Inst, InstSize);
-        else
-          // We don't care about splitting mixed atoms either.
-          llvm_unreachable("Couldn't disassemble instruction in atom.");
+          InvalidData = 0;
+        } else {
+          assert(InstSize && "getInstruction() consumed no bytes");
+          if (!InvalidData) {
+            Text = 0;
+            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);
@@ -94,13 +155,16 @@ void MCObjectDisassembler::buildSectionAtoms(MCModule *Module) {
 
 namespace {
   struct BBInfo;
-  typedef std::set<BBInfo*> BBInfoSetTy;
+  typedef SmallPtrSet<BBInfo*, 2> BBInfoSetTy;
 
   struct BBInfo {
     MCTextAtom *Atom;
     MCBasicBlock *BB;
     BBInfoSetTy Succs;
     BBInfoSetTy Preds;
+    MCObjectDisassembler::AddressSetTy SuccAddrs;
+
+    BBInfo() : Atom(0), BB(0) {}
 
     void addSucc(BBInfo &Succ) {
       Succs.insert(&Succ);
@@ -109,13 +173,33 @@ namespace {
   };
 }
 
+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;
-  typedef std::set<uint64_t> AddressSetTy;
   AddressSetTy Splits;
   AddressSetTy Calls;
 
+  error_code ec;
+  for (symbol_iterator SI = Obj.begin_symbols(), SE = Obj.end_symbols();
+       SI != SE; SI.increment(ec)) {
+    if (ec)
+      break;
+    SymbolRef::Type SymType;
+    SI->getType(SymType);
+    if (SymType == SymbolRef::ST_Function) {
+      uint64_t SymAddr;
+      SI->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!");
 
@@ -125,21 +209,24 @@ void MCObjectDisassembler::buildCFG(MCModule *Module) {
        AI != AE; ++AI) {
     MCTextAtom *TA = dyn_cast<MCTextAtom>(*AI);
     if (!TA) continue;
-    Calls.insert(TA->getBeginAddr());
+    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.insert(II->Address + II->Size);
+        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.insert(Target);
-        Splits.insert(Target);
+          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) {
@@ -185,8 +272,8 @@ void MCObjectDisassembler::buildCFG(MCModule *Module) {
     // Create MCBBs.
     SmallSetVector<BBInfo*, 16> Worklist;
     Worklist.insert(&BBI);
-    for (size_t WI = 0; WI < Worklist.size(); ++WI) {
-      BBInfo *BBI = Worklist[WI];
+    for (size_t wi = 0; wi < Worklist.size(); ++wi) {
+      BBInfo *BBI = Worklist[wi];
       if (!BBI->Atom)
         continue;
       BBI->BB = &MCFN.createBlock(*BBI->Atom);
@@ -200,17 +287,298 @@ void MCObjectDisassembler::buildCFG(MCModule *Module) {
     }
 
     // Set preds/succs.
-    for (size_t WI = 0; WI < Worklist.size(); ++WI) {
-      BBInfo *BBI = Worklist[WI];
+    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)
-        MCBB->addSuccessor((*SI)->BB);
+           SI != SE; ++SI)
+        if ((*SI)->BB)
+          MCBB->addSuccessor((*SI)->BB);
       for (BBInfoSetTy::iterator PI = BBI->Preds.begin(), PE = BBI->Preds.end();
-                                 PI != PE; ++PI)
-        MCBB->addPredecessor((*PI)->BB);
+           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();
+         SE != 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;
+  }
+
+  // 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) {
+
+  error_code ec;
+  for (section_iterator SI = MOOF.begin_sections(), SE = MOOF.end_sections();
+       SI != SE; SI.increment(ec)) {
+    if (ec)
+      break;
+    StringRef Name;
+    SI->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");
+      SI->getContents(ModInitContents);
+    } else if (Name == "__mod_exit_func") {
+      DEBUG(dbgs() << "Found __mod_exit_func section!\n");
+      SI->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);
 }