Enable exception handling int JIT

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47079 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 636 insertions, 0 deletions

diff --git a/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp b/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
new file mode 100644
index 0000000..230ae54
--- /dev/null
+++ b/lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp
@@ -0,0 +1,636 @@
+//===----- JITDwarfEmitter.cpp - Write dwarf tables into memory -----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a JITDwarfEmitter object that is used by the JIT to
+// write dwarf tables to memory.
+//
+//===----------------------------------------------------------------------===//
+
+#include "JIT.h"
+#include "JITDwarfEmitter.h"
+#include "llvm/Function.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/MachineCodeEmitter.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineLocation.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/ExecutionEngine/JITMemoryManager.h"
+#include "llvm/Target/TargetAsmInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetInstrInfo.h"
+#include "llvm/Target/TargetFrameInfo.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+
+using namespace llvm;
+
+JITDwarfEmitter::JITDwarfEmitter(JIT& theJit) : Jit(theJit) {}
+
+
+unsigned char* JITDwarfEmitter::EmitDwarfTable(MachineFunction& F, 
+                                               MachineCodeEmitter& mce,
+                                               unsigned char* StartFunction,
+                                               unsigned char* EndFunction) {
+  const TargetMachine& TM = F.getTarget();
+  TD = TM.getTargetData();
+  needsIndirectEncoding = TM.getTargetAsmInfo()->getNeedsIndirectEncoding();
+  stackGrowthDirection = TM.getFrameInfo()->getStackGrowthDirection();
+  RI = TM.getRegisterInfo();
+  MCE = &mce;
+  
+  unsigned char* ExceptionTable = EmitExceptionTable(&F, StartFunction,
+                                                     EndFunction);
+      
+  unsigned char* Result = 0;
+  unsigned char* EHFramePtr = 0;
+
+  const std::vector<Function *> Personalities = MMI->getPersonalities();
+  EHFramePtr = EmitCommonEHFrame(Personalities[MMI->getPersonalityIndex()]);
+
+  Result = EmitEHFrame(Personalities[MMI->getPersonalityIndex()], EHFramePtr,
+                       StartFunction, EndFunction, ExceptionTable);
+  
+  return Result;
+}
+
+
+void JITDwarfEmitter::EmitFrameMoves(intptr_t BaseLabelPtr,
+                                     const std::vector<MachineMove> &Moves) {
+  unsigned PointerSize = TD->getPointerSize();
+  int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
+          PointerSize : -PointerSize;
+  bool IsLocal = BaseLabelPtr;
+
+  for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
+    const MachineMove &Move = Moves[i];
+    unsigned LabelID = Move.getLabelID();
+    
+    if (LabelID) {
+      LabelID = MMI->MappedLabel(LabelID);
+    
+      // Throw out move if the label is invalid.
+      if (!LabelID) continue;
+    }
+    
+    intptr_t LabelPtr = 0;
+    if (LabelID) LabelPtr = MCE->getLabelAddress(LabelID);
+
+    const MachineLocation &Dst = Move.getDestination();
+    const MachineLocation &Src = Move.getSource();
+    
+    // Advance row if new location.
+    if (BaseLabelPtr && LabelID && (BaseLabelPtr != LabelPtr || !IsLocal)) {
+      MCE->emitByte(dwarf::DW_CFA_advance_loc4);
+      if (PointerSize == 8) {
+        MCE->emitInt64(LabelPtr - BaseLabelPtr);
+      } else {
+        MCE->emitInt32(LabelPtr - BaseLabelPtr);
+      }
+      
+      BaseLabelPtr = LabelPtr;
+      IsLocal = true;
+    }
+    
+    // If advancing cfa.
+    if (Dst.isRegister() && Dst.getRegister() == MachineLocation::VirtualFP) {
+      if (!Src.isRegister()) {
+        if (Src.getRegister() == MachineLocation::VirtualFP) {
+          MCE->emitByte(dwarf::DW_CFA_def_cfa_offset);
+        } else {
+          MCE->emitByte(dwarf::DW_CFA_def_cfa);
+          MCE->emitULEB128Bytes(RI->getDwarfRegNum(Src.getRegister(), true));
+        }
+        
+        int Offset = -Src.getOffset();
+        
+        MCE->emitULEB128Bytes(Offset);
+      } else {
+        assert(0 && "Machine move no supported yet.");
+      }
+    } else if (Src.isRegister() &&
+      Src.getRegister() == MachineLocation::VirtualFP) {
+      if (Dst.isRegister()) {
+        MCE->emitByte(dwarf::DW_CFA_def_cfa_register);
+        MCE->emitULEB128Bytes(RI->getDwarfRegNum(Dst.getRegister(), true));
+      } else {
+        assert(0 && "Machine move no supported yet.");
+      }
+    } else {
+      unsigned Reg = RI->getDwarfRegNum(Src.getRegister(), true);
+      int Offset = Dst.getOffset() / stackGrowth;
+      
+      if (Offset < 0) {
+        MCE->emitByte(dwarf::DW_CFA_offset_extended_sf);
+        MCE->emitULEB128Bytes(Reg);
+        MCE->emitSLEB128Bytes(Offset);
+      } else if (Reg < 64) {
+        MCE->emitByte(dwarf::DW_CFA_offset + Reg);
+        MCE->emitULEB128Bytes(Offset);
+      } else {
+        MCE->emitByte(dwarf::DW_CFA_offset_extended);
+        MCE->emitULEB128Bytes(Reg);
+        MCE->emitULEB128Bytes(Offset);
+      }
+    }
+  }
+}
+
+/// SharedTypeIds - How many leading type ids two landing pads have in common.
+static unsigned SharedTypeIds(const LandingPadInfo *L,
+                              const LandingPadInfo *R) {
+  const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
+  unsigned LSize = LIds.size(), RSize = RIds.size();
+  unsigned MinSize = LSize < RSize ? LSize : RSize;
+  unsigned Count = 0;
+
+  for (; Count != MinSize; ++Count)
+    if (LIds[Count] != RIds[Count])
+      return Count;
+
+  return Count;
+}
+
+
+/// PadLT - Order landing pads lexicographically by type id.
+static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
+  const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
+  unsigned LSize = LIds.size(), RSize = RIds.size();
+  unsigned MinSize = LSize < RSize ? LSize : RSize;
+
+  for (unsigned i = 0; i != MinSize; ++i)
+    if (LIds[i] != RIds[i])
+      return LIds[i] < RIds[i];
+
+  return LSize < RSize;
+}
+
+struct KeyInfo {
+  static inline unsigned getEmptyKey() { return -1U; }
+  static inline unsigned getTombstoneKey() { return -2U; }
+  static unsigned getHashValue(const unsigned &Key) { return Key; }
+  static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
+  static bool isPod() { return true; }
+};
+
+/// ActionEntry - Structure describing an entry in the actions table.
+struct ActionEntry {
+  int ValueForTypeID; // The value to write - may not be equal to the type id.
+  int NextAction;
+  struct ActionEntry *Previous;
+};
+
+/// PadRange - Structure holding a try-range and the associated landing pad.
+struct PadRange {
+  // The index of the landing pad.
+  unsigned PadIndex;
+  // The index of the begin and end labels in the landing pad's label lists.
+  unsigned RangeIndex;
+};
+
+typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType;
+
+/// CallSiteEntry - Structure describing an entry in the call-site table.
+struct CallSiteEntry {
+  unsigned BeginLabel; // zero indicates the start of the function.
+  unsigned EndLabel;   // zero indicates the end of the function.
+  unsigned PadLabel;   // zero indicates that there is no landing pad.
+  unsigned Action;
+};
+
+unsigned char* JITDwarfEmitter::EmitExceptionTable(MachineFunction* MF,
+                                         unsigned char* StartFunction,
+                                         unsigned char* EndFunction) {
+  // Map all labels and get rid of any dead landing pads.
+  MMI->TidyLandingPads();
+
+  const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
+  const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
+  const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
+  if (PadInfos.empty()) return 0;
+
+  // Sort the landing pads in order of their type ids.  This is used to fold
+  // duplicate actions.
+  SmallVector<const LandingPadInfo *, 64> LandingPads;
+  LandingPads.reserve(PadInfos.size());
+  for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
+    LandingPads.push_back(&PadInfos[i]);
+  std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
+
+  // Negative type ids index into FilterIds, positive type ids index into
+  // TypeInfos.  The value written for a positive type id is just the type
+  // id itself.  For a negative type id, however, the value written is the
+  // (negative) byte offset of the corresponding FilterIds entry.  The byte
+  // offset is usually equal to the type id, because the FilterIds entries
+  // are written using a variable width encoding which outputs one byte per
+  // entry as long as the value written is not too large, but can differ.
+  // This kind of complication does not occur for positive type ids because
+  // type infos are output using a fixed width encoding.
+  // FilterOffsets[i] holds the byte offset corresponding to FilterIds[i].
+  SmallVector<int, 16> FilterOffsets;
+  FilterOffsets.reserve(FilterIds.size());
+  int Offset = -1;
+  for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
+    E = FilterIds.end(); I != E; ++I) {
+    FilterOffsets.push_back(Offset);
+    Offset -= AsmPrinter::SizeULEB128(*I);
+  }
+
+  // Compute the actions table and gather the first action index for each
+  // landing pad site.
+  SmallVector<ActionEntry, 32> Actions;
+  SmallVector<unsigned, 64> FirstActions;
+  FirstActions.reserve(LandingPads.size());
+
+  int FirstAction = 0;
+  unsigned SizeActions = 0;
+  for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
+    const LandingPadInfo *LP = LandingPads[i];
+    const std::vector<int> &TypeIds = LP->TypeIds;
+    const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
+    unsigned SizeSiteActions = 0;
+
+    if (NumShared < TypeIds.size()) {
+      unsigned SizeAction = 0;
+      ActionEntry *PrevAction = 0;
+
+      if (NumShared) {
+        const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
+        assert(Actions.size());
+        PrevAction = &Actions.back();
+        SizeAction = AsmPrinter::SizeSLEB128(PrevAction->NextAction) +
+          AsmPrinter::SizeSLEB128(PrevAction->ValueForTypeID);
+        for (unsigned j = NumShared; j != SizePrevIds; ++j) {
+          SizeAction -= AsmPrinter::SizeSLEB128(PrevAction->ValueForTypeID);
+          SizeAction += -PrevAction->NextAction;
+          PrevAction = PrevAction->Previous;
+        }
+      }
+
+      // Compute the actions.
+      for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
+        int TypeID = TypeIds[I];
+        assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
+        int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
+        unsigned SizeTypeID = AsmPrinter::SizeSLEB128(ValueForTypeID);
+
+        int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
+        SizeAction = SizeTypeID + AsmPrinter::SizeSLEB128(NextAction);
+        SizeSiteActions += SizeAction;
+
+        ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
+        Actions.push_back(Action);
+
+        PrevAction = &Actions.back();
+      }
+
+      // Record the first action of the landing pad site.
+      FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
+    } // else identical - re-use previous FirstAction
+
+    FirstActions.push_back(FirstAction);
+
+    // Compute this sites contribution to size.
+    SizeActions += SizeSiteActions;
+  }
+
+  // Compute the call-site table.  Entries must be ordered by address.
+  SmallVector<CallSiteEntry, 64> CallSites;
+
+  RangeMapType PadMap;
+  for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
+    const LandingPadInfo *LandingPad = LandingPads[i];
+    for (unsigned j=0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
+      unsigned BeginLabel = LandingPad->BeginLabels[j];
+      assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
+      PadRange P = { i, j };
+      PadMap[BeginLabel] = P;
+    }
+  }
+
+  bool MayThrow = false;
+  unsigned LastLabel = 0;
+  for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
+        I != E; ++I) {
+    for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
+          MI != E; ++MI) {
+      if (MI->getOpcode() != TargetInstrInfo::LABEL) {
+        MayThrow |= MI->getDesc().isCall();
+        continue;
+      }
+
+      unsigned BeginLabel = MI->getOperand(0).getImm();
+      assert(BeginLabel && "Invalid label!");
+
+      if (BeginLabel == LastLabel)
+        MayThrow = false;
+
+      RangeMapType::iterator L = PadMap.find(BeginLabel);
+
+      if (L == PadMap.end())
+        continue;
+
+      PadRange P = L->second;
+      const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
+
+      assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
+              "Inconsistent landing pad map!");
+
+      // If some instruction between the previous try-range and this one may
+      // throw, create a call-site entry with no landing pad for the region
+      // between the try-ranges.
+      if (MayThrow) {
+        CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
+        CallSites.push_back(Site);
+      }
+
+      LastLabel = LandingPad->EndLabels[P.RangeIndex];
+      CallSiteEntry Site = {BeginLabel, LastLabel,
+        LandingPad->LandingPadLabel, FirstActions[P.PadIndex]};
+
+      assert(Site.BeginLabel && Site.EndLabel && Site.PadLabel &&
+              "Invalid landing pad!");
+
+      // Try to merge with the previous call-site.
+      if (CallSites.size()) {
+        CallSiteEntry &Prev = CallSites[CallSites.size()-1];
+        if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
+          // Extend the range of the previous entry.
+          Prev.EndLabel = Site.EndLabel;
+          continue;
+        }
+      }
+
+      // Otherwise, create a new call-site.
+      CallSites.push_back(Site);
+    }
+  }
+  // If some instruction between the previous try-range and the end of the
+  // function may throw, create a call-site entry with no landing pad for the
+  // region following the try-range.
+  if (MayThrow) {
+    CallSiteEntry Site = {LastLabel, 0, 0, 0};
+    CallSites.push_back(Site);
+  }
+
+  // Final tallies.
+  unsigned SizeSites = CallSites.size() * (sizeof(int32_t) + // Site start.
+                                            sizeof(int32_t) + // Site length.
+                                            sizeof(int32_t)); // Landing pad.
+  for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
+    SizeSites += AsmPrinter::SizeULEB128(CallSites[i].Action);
+
+  unsigned SizeTypes = TypeInfos.size() * TD->getPointerSize();
+
+  unsigned TypeOffset = sizeof(int8_t) + // Call site format
+                        // Call-site table length
+                        AsmPrinter::SizeULEB128(SizeSites) + 
+                        SizeSites + SizeActions + SizeTypes;
+
+  unsigned TotalSize = sizeof(int8_t) + // LPStart format
+                       sizeof(int8_t) + // TType format
+                       AsmPrinter::SizeULEB128(TypeOffset) + // TType base offset
+                       TypeOffset;
+
+  unsigned SizeAlign = (4 - TotalSize) & 3;
+
+  // Begin the exception table.
+  MCE->emitAlignment(4);
+  for (unsigned i = 0; i != SizeAlign; ++i) {
+    MCE->emitByte(0);
+    // Asm->EOL("Padding");
+  }
+  
+  unsigned char* DwarfExceptionTable = (unsigned char*)MCE->getCurrentPCValue();
+
+  // Emit the header.
+  MCE->emitByte(dwarf::DW_EH_PE_omit);
+  // Asm->EOL("LPStart format (DW_EH_PE_omit)");
+  MCE->emitByte(dwarf::DW_EH_PE_absptr);
+  // Asm->EOL("TType format (DW_EH_PE_absptr)");
+  MCE->emitULEB128Bytes(TypeOffset);
+  // Asm->EOL("TType base offset");
+  MCE->emitByte(dwarf::DW_EH_PE_udata4);
+  // Asm->EOL("Call site format (DW_EH_PE_udata4)");
+  MCE->emitULEB128Bytes(SizeSites);
+  // Asm->EOL("Call-site table length");
+
+  // Emit the landing pad site information.
+  for (unsigned i = 0; i < CallSites.size(); ++i) {
+    CallSiteEntry &S = CallSites[i];
+    intptr_t BeginLabelPtr = 0;
+    intptr_t EndLabelPtr = 0;
+
+    if (!S.BeginLabel) {
+      BeginLabelPtr = (intptr_t)StartFunction;
+      if (TD->getPointerSize() == sizeof(int32_t))
+        MCE->emitInt32(0);
+      else
+        MCE->emitInt64(0);
+    } else {
+      BeginLabelPtr = MCE->getLabelAddress(S.BeginLabel);
+      if (TD->getPointerSize() == sizeof(int32_t))
+        MCE->emitInt32(BeginLabelPtr - (intptr_t)StartFunction);
+      else
+        MCE->emitInt64(BeginLabelPtr - (intptr_t)StartFunction);
+    }
+
+    // Asm->EOL("Region start");
+
+    if (!S.EndLabel) {
+      EndLabelPtr = (intptr_t)EndFunction;
+      if (TD->getPointerSize() == sizeof(int32_t))
+        MCE->emitInt32((intptr_t)EndFunction - BeginLabelPtr);
+      else
+        MCE->emitInt64((intptr_t)EndFunction - BeginLabelPtr);
+    } else {
+      EndLabelPtr = MCE->getLabelAddress(S.EndLabel);
+      if (TD->getPointerSize() == sizeof(int32_t))
+        MCE->emitInt32(EndLabelPtr - BeginLabelPtr);
+      else
+        MCE->emitInt64(EndLabelPtr - BeginLabelPtr);
+    }
+    //Asm->EOL("Region length");
+
+    if (!S.PadLabel) {
+      if (TD->getPointerSize() == sizeof(int32_t))
+        MCE->emitInt32(0);
+      else
+        MCE->emitInt64(0);
+    } else {
+      unsigned PadLabelPtr = MCE->getLabelAddress(S.PadLabel);
+      if (TD->getPointerSize() == sizeof(int32_t))
+        MCE->emitInt32(PadLabelPtr - (intptr_t)StartFunction);
+      else
+        MCE->emitInt64(PadLabelPtr - (intptr_t)StartFunction);
+    }
+    // Asm->EOL("Landing pad");
+
+    MCE->emitULEB128Bytes(S.Action);
+    // Asm->EOL("Action");
+  }
+
+  // Emit the actions.
+  for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
+    ActionEntry &Action = Actions[I];
+
+    MCE->emitSLEB128Bytes(Action.ValueForTypeID);
+    //Asm->EOL("TypeInfo index");
+    MCE->emitSLEB128Bytes(Action.NextAction);
+    //Asm->EOL("Next action");
+  }
+
+  // Emit the type ids.
+  for (unsigned M = TypeInfos.size(); M; --M) {
+    GlobalVariable *GV = TypeInfos[M - 1];
+    
+    if (GV) {
+      if (TD->getPointerSize() == sizeof(int32_t)) {
+        MCE->emitInt32((intptr_t)Jit.getOrEmitGlobalVariable(GV));
+      } else {
+        MCE->emitInt64((intptr_t)Jit.getOrEmitGlobalVariable(GV));
+      }
+    } else {
+      if (TD->getPointerSize() == sizeof(int32_t))
+        MCE->emitInt32(0);
+      else
+        MCE->emitInt64(0);
+    }
+    // Asm->EOL("TypeInfo");
+  }
+
+  // Emit the filter typeids.
+  for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
+    unsigned TypeID = FilterIds[j];
+    MCE->emitULEB128Bytes(TypeID);
+    //Asm->EOL("Filter TypeInfo index");
+  }
+  
+  MCE->emitAlignment(4);
+
+  return DwarfExceptionTable;
+}
+
+unsigned char* JITDwarfEmitter::EmitCommonEHFrame(const Function* Personality) {
+  unsigned PointerSize = TD->getPointerSize();
+  int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
+          PointerSize : -PointerSize;
+  
+  unsigned char* StartCommonPtr = (unsigned char*)MCE->getCurrentPCValue();
+  // EH Common Frame header
+  MCE->allocateSpace(PointerSize, 0);
+  unsigned char* FrameCommonBeginPtr = (unsigned char*)MCE->getCurrentPCValue();
+  MCE->emitInt32((int)0);
+  MCE->emitByte(dwarf::DW_CIE_VERSION);
+  MCE->emitString(Personality ? "zPLR" : "zR");
+  MCE->emitULEB128Bytes(1);
+  MCE->emitSLEB128Bytes(stackGrowth);
+  MCE->emitByte(RI->getDwarfRegNum(RI->getRARegister(), true));
+  
+  if (Personality) {
+    MCE->emitULEB128Bytes(7);
+    
+    if (needsIndirectEncoding)
+      MCE->emitByte(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 | 
+               dwarf::DW_EH_PE_indirect);
+    else
+      MCE->emitByte(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
+
+    if (PointerSize == 8)
+      MCE->emitInt64((intptr_t)Jit.getPointerToGlobal(Personality) - 
+                MCE->getCurrentPCValue());
+    else
+      MCE->emitInt32((intptr_t)Jit.getPointerToGlobal(Personality) - 
+                MCE->getCurrentPCValue());
+    
+    MCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel);
+    MCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel);
+      
+  } else {
+    MCE->emitULEB128Bytes(1);
+    MCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel);
+  }
+
+  std::vector<MachineMove> Moves;
+  RI->getInitialFrameState(Moves);
+  EmitFrameMoves(0, Moves);
+  MCE->emitAlignment(4);
+  
+  MCE->emitAt((uintptr_t*)StartCommonPtr, 
+              (uintptr_t)((unsigned char*)MCE->getCurrentPCValue() - 
+                          FrameCommonBeginPtr));
+
+  return StartCommonPtr;
+}
+
+
+unsigned char* JITDwarfEmitter::EmitEHFrame(const Function* Personality,
+                                            unsigned char* StartCommonPtr,
+                                            unsigned char* StartFunction, 
+                                            unsigned char* EndFunction,
+                                            unsigned char* ExceptionTable) {
+  unsigned PointerSize = TD->getPointerSize();
+  
+  // EH frame header.
+  unsigned char* StartEHPtr = (unsigned char*)MCE->getCurrentPCValue();
+  MCE->allocateSpace(PointerSize, 0);
+  unsigned char* FrameBeginPtr = (unsigned char*)MCE->getCurrentPCValue();
+  // FDE CIE Offset
+  if (PointerSize == 8) {
+    MCE->emitInt64(FrameBeginPtr - StartCommonPtr);
+    MCE->emitInt64(StartFunction - (unsigned char*)MCE->getCurrentPCValue());
+    MCE->emitInt64(EndFunction - StartFunction);
+  } else {
+    MCE->emitInt32(FrameBeginPtr - StartCommonPtr);
+    MCE->emitInt32(StartFunction - (unsigned char*)MCE->getCurrentPCValue());
+    MCE->emitInt32(EndFunction - StartFunction);
+  }
+
+  // If there is a personality and landing pads then point to the language
+  // specific data area in the exception table.
+  if (MMI->getPersonalityIndex()) {
+    MCE->emitULEB128Bytes(4);
+        
+    if (!MMI->getLandingPads().empty()) {
+      if (PointerSize == 8)
+        MCE->emitInt64(ExceptionTable - (unsigned char*)MCE->getCurrentPCValue());
+      else
+        MCE->emitInt32(ExceptionTable - (unsigned char*)MCE->getCurrentPCValue());
+    } else if (PointerSize == 8) {
+      MCE->emitInt64((int)0);
+    } else {
+      MCE->emitInt32((int)0);
+    }
+  } else {
+    MCE->emitULEB128Bytes(0);
+  }
+      
+  // Indicate locations of function specific  callee saved registers in
+  // frame.
+  EmitFrameMoves((intptr_t)StartFunction, MMI->getFrameMoves());
+      
+  MCE->emitAlignment(4);
+  
+  // Indicate the size of the table
+  MCE->emitAt((uintptr_t*)StartEHPtr, 
+              (uintptr_t)((unsigned char*)MCE->getCurrentPCValue() - 
+                          StartEHPtr));
+  
+  // Double zeroes for the unwind runtime
+  if (PointerSize == 8) {
+    MCE->emitInt64(0);
+    MCE->emitInt64(0);
+  } else {
+    MCE->emitInt32(0);
+    MCE->emitInt32(0);
+  }
+
+  
+  return StartEHPtr;
+}