lib/ExecutionEngine/JIT/JITDwarfEmitter.cpp

   1 //===----- JITDwarfEmitter.cpp - Write dwarf tables into memory -----------===//
   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 a JITDwarfEmitter object that is used by the JIT to
  11 // write dwarf tables to memory.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "JIT.h"
  16 #include "JITDwarfEmitter.h"
  17 #include "llvm/Function.h"
  18 #include "llvm/ADT/DenseMap.h"
  19 #include "llvm/CodeGen/JITCodeEmitter.h"
  20 #include "llvm/CodeGen/MachineFunction.h"
  21 #include "llvm/CodeGen/MachineLocation.h"
  22 #include "llvm/CodeGen/MachineModuleInfo.h"
  23 #include "llvm/ExecutionEngine/JITMemoryManager.h"
  24 #include "llvm/Support/ErrorHandling.h"
  25 #include "llvm/MC/MCAsmInfo.h"
  26 #include "llvm/Target/TargetData.h"
  27 #include "llvm/Target/TargetInstrInfo.h"
  28 #include "llvm/Target/TargetFrameInfo.h"
  29 #include "llvm/Target/TargetMachine.h"
  30 #include "llvm/Target/TargetRegisterInfo.h"
  31 using namespace llvm;
  32
  33 JITDwarfEmitter::JITDwarfEmitter(JIT& theJit) : Jit(theJit) {}
  34
  35
  36 unsigned char* JITDwarfEmitter::EmitDwarfTable(MachineFunction& F,
  37                                                JITCodeEmitter& jce,
  38                                                unsigned char* StartFunction,
  39                                                unsigned char* EndFunction) {
  40   const TargetMachine& TM = F.getTarget();
  41   TD = TM.getTargetData();
  42   needsIndirectEncoding = TM.getMCAsmInfo()->getNeedsIndirectEncoding();
  43   stackGrowthDirection = TM.getFrameInfo()->getStackGrowthDirection();
  44   RI = TM.getRegisterInfo();
  45   JCE = &jce;
  46
  47   unsigned char* ExceptionTable = EmitExceptionTable(&F, StartFunction,
  48                                                      EndFunction);
  49
  50   unsigned char* Result = 0;
  51   unsigned char* EHFramePtr = 0;
  52
  53   const std::vector<Function *> Personalities = MMI->getPersonalities();
  54   EHFramePtr = EmitCommonEHFrame(Personalities[MMI->getPersonalityIndex()]);
  55
  56   Result = EmitEHFrame(Personalities[MMI->getPersonalityIndex()], EHFramePtr,
  57                        StartFunction, EndFunction, ExceptionTable);
  58
  59   return Result;
  60 }
  61
  62
  63 void
  64 JITDwarfEmitter::EmitFrameMoves(intptr_t BaseLabelPtr,
  65                                 const std::vector<MachineMove> &Moves) const {
  66   unsigned PointerSize = TD->getPointerSize();
  67   int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
  68           PointerSize : -PointerSize;
  69   bool IsLocal = false;
  70   unsigned BaseLabelID = 0;
  71
  72   for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
  73     const MachineMove &Move = Moves[i];
  74     unsigned LabelID = Move.getLabelID();
  75
  76     if (LabelID) {
  77       LabelID = MMI->MappedLabel(LabelID);
  78
  79       // Throw out move if the label is invalid.
  80       if (!LabelID) continue;
  81     }
  82
  83     intptr_t LabelPtr = 0;
  84     if (LabelID) LabelPtr = JCE->getLabelAddress(LabelID);
  85
  86     const MachineLocation &Dst = Move.getDestination();
  87     const MachineLocation &Src = Move.getSource();
  88
  89     // Advance row if new location.
  90     if (BaseLabelPtr && LabelID && (BaseLabelID != LabelID || !IsLocal)) {
  91       JCE->emitByte(dwarf::DW_CFA_advance_loc4);
  92       JCE->emitInt32(LabelPtr - BaseLabelPtr);
  93
  94       BaseLabelID = LabelID;
  95       BaseLabelPtr = LabelPtr;
  96       IsLocal = true;
  97     }
  98
  99     // If advancing cfa.
 100     if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
 101       if (!Src.isReg()) {
 102         if (Src.getReg() == MachineLocation::VirtualFP) {
 103           JCE->emitByte(dwarf::DW_CFA_def_cfa_offset);
 104         } else {
 105           JCE->emitByte(dwarf::DW_CFA_def_cfa);
 106           JCE->emitULEB128Bytes(RI->getDwarfRegNum(Src.getReg(), true));
 107         }
 108
 109         JCE->emitULEB128Bytes(-Src.getOffset());
 110       } else {
 111         llvm_unreachable("Machine move not supported yet.");
 112       }
 113     } else if (Src.isReg() &&
 114       Src.getReg() == MachineLocation::VirtualFP) {
 115       if (Dst.isReg()) {
 116         JCE->emitByte(dwarf::DW_CFA_def_cfa_register);
 117         JCE->emitULEB128Bytes(RI->getDwarfRegNum(Dst.getReg(), true));
 118       } else {
 119         llvm_unreachable("Machine move not supported yet.");
 120       }
 121     } else {
 122       unsigned Reg = RI->getDwarfRegNum(Src.getReg(), true);
 123       int Offset = Dst.getOffset() / stackGrowth;
 124
 125       if (Offset < 0) {
 126         JCE->emitByte(dwarf::DW_CFA_offset_extended_sf);
 127         JCE->emitULEB128Bytes(Reg);
 128         JCE->emitSLEB128Bytes(Offset);
 129       } else if (Reg < 64) {
 130         JCE->emitByte(dwarf::DW_CFA_offset + Reg);
 131         JCE->emitULEB128Bytes(Offset);
 132       } else {
 133         JCE->emitByte(dwarf::DW_CFA_offset_extended);
 134         JCE->emitULEB128Bytes(Reg);
 135         JCE->emitULEB128Bytes(Offset);
 136       }
 137     }
 138   }
 139 }
 140
 141 /// SharedTypeIds - How many leading type ids two landing pads have in common.
 142 static unsigned SharedTypeIds(const LandingPadInfo *L,
 143                               const LandingPadInfo *R) {
 144   const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
 145   unsigned LSize = LIds.size(), RSize = RIds.size();
 146   unsigned MinSize = LSize < RSize ? LSize : RSize;
 147   unsigned Count = 0;
 148
 149   for (; Count != MinSize; ++Count)
 150     if (LIds[Count] != RIds[Count])
 151       return Count;
 152
 153   return Count;
 154 }
 155
 156
 157 /// PadLT - Order landing pads lexicographically by type id.
 158 static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
 159   const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
 160   unsigned LSize = LIds.size(), RSize = RIds.size();
 161   unsigned MinSize = LSize < RSize ? LSize : RSize;
 162
 163   for (unsigned i = 0; i != MinSize; ++i)
 164     if (LIds[i] != RIds[i])
 165       return LIds[i] < RIds[i];
 166
 167   return LSize < RSize;
 168 }
 169
 170 namespace {
 171
 172 struct KeyInfo {
 173   static inline unsigned getEmptyKey() { return -1U; }
 174   static inline unsigned getTombstoneKey() { return -2U; }
 175   static unsigned getHashValue(const unsigned &Key) { return Key; }
 176   static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
 177   static bool isPod() { return true; }
 178 };
 179
 180 /// ActionEntry - Structure describing an entry in the actions table.
 181 struct ActionEntry {
 182   int ValueForTypeID; // The value to write - may not be equal to the type id.
 183   int NextAction;
 184   struct ActionEntry *Previous;
 185 };
 186
 187 /// PadRange - Structure holding a try-range and the associated landing pad.
 188 struct PadRange {
 189   // The index of the landing pad.
 190   unsigned PadIndex;
 191   // The index of the begin and end labels in the landing pad's label lists.
 192   unsigned RangeIndex;
 193 };
 194
 195 typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType;
 196
 197 /// CallSiteEntry - Structure describing an entry in the call-site table.
 198 struct CallSiteEntry {
 199   unsigned BeginLabel; // zero indicates the start of the function.
 200   unsigned EndLabel;   // zero indicates the end of the function.
 201   unsigned PadLabel;   // zero indicates that there is no landing pad.
 202   unsigned Action;
 203 };
 204
 205 }
 206
 207 unsigned char* JITDwarfEmitter::EmitExceptionTable(MachineFunction* MF,
 208                                          unsigned char* StartFunction,
 209                                          unsigned char* EndFunction) const {
 210   // Map all labels and get rid of any dead landing pads.
 211   MMI->TidyLandingPads();
 212
 213   const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
 214   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
 215   const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
 216   if (PadInfos.empty()) return 0;
 217
 218   // Sort the landing pads in order of their type ids.  This is used to fold
 219   // duplicate actions.
 220   SmallVector<const LandingPadInfo *, 64> LandingPads;
 221   LandingPads.reserve(PadInfos.size());
 222   for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
 223     LandingPads.push_back(&PadInfos[i]);
 224   std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
 225
 226   // Negative type ids index into FilterIds, positive type ids index into
 227   // TypeInfos.  The value written for a positive type id is just the type
 228   // id itself.  For a negative type id, however, the value written is the
 229   // (negative) byte offset of the corresponding FilterIds entry.  The byte
 230   // offset is usually equal to the type id, because the FilterIds entries
 231   // are written using a variable width encoding which outputs one byte per
 232   // entry as long as the value written is not too large, but can differ.
 233   // This kind of complication does not occur for positive type ids because
 234   // type infos are output using a fixed width encoding.
 235   // FilterOffsets[i] holds the byte offset corresponding to FilterIds[i].
 236   SmallVector<int, 16> FilterOffsets;
 237   FilterOffsets.reserve(FilterIds.size());
 238   int Offset = -1;
 239   for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
 240     E = FilterIds.end(); I != E; ++I) {
 241     FilterOffsets.push_back(Offset);
 242     Offset -= MCAsmInfo::getULEB128Size(*I);
 243   }
 244
 245   // Compute the actions table and gather the first action index for each
 246   // landing pad site.
 247   SmallVector<ActionEntry, 32> Actions;
 248   SmallVector<unsigned, 64> FirstActions;
 249   FirstActions.reserve(LandingPads.size());
 250
 251   int FirstAction = 0;
 252   unsigned SizeActions = 0;
 253   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
 254     const LandingPadInfo *LP = LandingPads[i];
 255     const std::vector<int> &TypeIds = LP->TypeIds;
 256     const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
 257     unsigned SizeSiteActions = 0;
 258
 259     if (NumShared < TypeIds.size()) {
 260       unsigned SizeAction = 0;
 261       ActionEntry *PrevAction = 0;
 262
 263       if (NumShared) {
 264         const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
 265         assert(Actions.size());
 266         PrevAction = &Actions.back();
 267         SizeAction = MCAsmInfo::getSLEB128Size(PrevAction->NextAction) +
 268           MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
 269         for (unsigned j = NumShared; j != SizePrevIds; ++j) {
 270           SizeAction -= MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
 271           SizeAction += -PrevAction->NextAction;
 272           PrevAction = PrevAction->Previous;
 273         }
 274       }
 275
 276       // Compute the actions.
 277       for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
 278         int TypeID = TypeIds[I];
 279         assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
 280         int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
 281         unsigned SizeTypeID = MCAsmInfo::getSLEB128Size(ValueForTypeID);
 282
 283         int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
 284         SizeAction = SizeTypeID + MCAsmInfo::getSLEB128Size(NextAction);
 285         SizeSiteActions += SizeAction;
 286
 287         ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
 288         Actions.push_back(Action);
 289
 290         PrevAction = &Actions.back();
 291       }
 292
 293       // Record the first action of the landing pad site.
 294       FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
 295     } // else identical - re-use previous FirstAction
 296
 297     FirstActions.push_back(FirstAction);
 298
 299     // Compute this sites contribution to size.
 300     SizeActions += SizeSiteActions;
 301   }
 302
 303   // Compute the call-site table.  Entries must be ordered by address.
 304   SmallVector<CallSiteEntry, 64> CallSites;
 305
 306   RangeMapType PadMap;
 307   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
 308     const LandingPadInfo *LandingPad = LandingPads[i];
 309     for (unsigned j=0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
 310       unsigned BeginLabel = LandingPad->BeginLabels[j];
 311       assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
 312       PadRange P = { i, j };
 313       PadMap[BeginLabel] = P;
 314     }
 315   }
 316
 317   bool MayThrow = false;
 318   unsigned LastLabel = 0;
 319   for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
 320         I != E; ++I) {
 321     for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
 322           MI != E; ++MI) {
 323       if (!MI->isLabel()) {
 324         MayThrow |= MI->getDesc().isCall();
 325         continue;
 326       }
 327
 328       unsigned BeginLabel = MI->getOperand(0).getImm();
 329       assert(BeginLabel && "Invalid label!");
 330
 331       if (BeginLabel == LastLabel)
 332         MayThrow = false;
 333
 334       RangeMapType::iterator L = PadMap.find(BeginLabel);
 335
 336       if (L == PadMap.end())
 337         continue;
 338
 339       PadRange P = L->second;
 340       const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
 341
 342       assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
 343               "Inconsistent landing pad map!");
 344
 345       // If some instruction between the previous try-range and this one may
 346       // throw, create a call-site entry with no landing pad for the region
 347       // between the try-ranges.
 348       if (MayThrow) {
 349         CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
 350         CallSites.push_back(Site);
 351       }
 352
 353       LastLabel = LandingPad->EndLabels[P.RangeIndex];
 354       CallSiteEntry Site = {BeginLabel, LastLabel,
 355         LandingPad->LandingPadLabel, FirstActions[P.PadIndex]};
 356
 357       assert(Site.BeginLabel && Site.EndLabel && Site.PadLabel &&
 358               "Invalid landing pad!");
 359
 360       // Try to merge with the previous call-site.
 361       if (CallSites.size()) {
 362         CallSiteEntry &Prev = CallSites.back();
 363         if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
 364           // Extend the range of the previous entry.
 365           Prev.EndLabel = Site.EndLabel;
 366           continue;
 367         }
 368       }
 369
 370       // Otherwise, create a new call-site.
 371       CallSites.push_back(Site);
 372     }
 373   }
 374   // If some instruction between the previous try-range and the end of the
 375   // function may throw, create a call-site entry with no landing pad for the
 376   // region following the try-range.
 377   if (MayThrow) {
 378     CallSiteEntry Site = {LastLabel, 0, 0, 0};
 379     CallSites.push_back(Site);
 380   }
 381
 382   // Final tallies.
 383   unsigned SizeSites = CallSites.size() * (sizeof(int32_t) + // Site start.
 384                                             sizeof(int32_t) + // Site length.
 385                                             sizeof(int32_t)); // Landing pad.
 386   for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
 387     SizeSites += MCAsmInfo::getULEB128Size(CallSites[i].Action);
 388
 389   unsigned SizeTypes = TypeInfos.size() * TD->getPointerSize();
 390
 391   unsigned TypeOffset = sizeof(int8_t) + // Call site format
 392                         // Call-site table length
 393                         MCAsmInfo::getULEB128Size(SizeSites) +
 394                         SizeSites + SizeActions + SizeTypes;
 395
 396   // Begin the exception table.
 397   JCE->emitAlignmentWithFill(4, 0);
 398   // Asm->EOL("Padding");
 399
 400   unsigned char* DwarfExceptionTable = (unsigned char*)JCE->getCurrentPCValue();
 401
 402   // Emit the header.
 403   JCE->emitByte(dwarf::DW_EH_PE_omit);
 404   // Asm->EOL("LPStart format (DW_EH_PE_omit)");
 405   JCE->emitByte(dwarf::DW_EH_PE_absptr);
 406   // Asm->EOL("TType format (DW_EH_PE_absptr)");
 407   JCE->emitULEB128Bytes(TypeOffset);
 408   // Asm->EOL("TType base offset");
 409   JCE->emitByte(dwarf::DW_EH_PE_udata4);
 410   // Asm->EOL("Call site format (DW_EH_PE_udata4)");
 411   JCE->emitULEB128Bytes(SizeSites);
 412   // Asm->EOL("Call-site table length");
 413
 414   // Emit the landing pad site information.
 415   for (unsigned i = 0; i < CallSites.size(); ++i) {
 416     CallSiteEntry &S = CallSites[i];
 417     intptr_t BeginLabelPtr = 0;
 418     intptr_t EndLabelPtr = 0;
 419
 420     if (!S.BeginLabel) {
 421       BeginLabelPtr = (intptr_t)StartFunction;
 422       JCE->emitInt32(0);
 423     } else {
 424       BeginLabelPtr = JCE->getLabelAddress(S.BeginLabel);
 425       JCE->emitInt32(BeginLabelPtr - (intptr_t)StartFunction);
 426     }
 427
 428     // Asm->EOL("Region start");
 429
 430     if (!S.EndLabel) {
 431       EndLabelPtr = (intptr_t)EndFunction;
 432       JCE->emitInt32((intptr_t)EndFunction - BeginLabelPtr);
 433     } else {
 434       EndLabelPtr = JCE->getLabelAddress(S.EndLabel);
 435       JCE->emitInt32(EndLabelPtr - BeginLabelPtr);
 436     }
 437     //Asm->EOL("Region length");
 438
 439     if (!S.PadLabel) {
 440       JCE->emitInt32(0);
 441     } else {
 442       unsigned PadLabelPtr = JCE->getLabelAddress(S.PadLabel);
 443       JCE->emitInt32(PadLabelPtr - (intptr_t)StartFunction);
 444     }
 445     // Asm->EOL("Landing pad");
 446
 447     JCE->emitULEB128Bytes(S.Action);
 448     // Asm->EOL("Action");
 449   }
 450
 451   // Emit the actions.
 452   for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
 453     ActionEntry &Action = Actions[I];
 454
 455     JCE->emitSLEB128Bytes(Action.ValueForTypeID);
 456     //Asm->EOL("TypeInfo index");
 457     JCE->emitSLEB128Bytes(Action.NextAction);
 458     //Asm->EOL("Next action");
 459   }
 460
 461   // Emit the type ids.
 462   for (unsigned M = TypeInfos.size(); M; --M) {
 463     GlobalVariable *GV = TypeInfos[M - 1];
 464
 465     if (GV) {
 466       if (TD->getPointerSize() == sizeof(int32_t))
 467         JCE->emitInt32((intptr_t)Jit.getOrEmitGlobalVariable(GV));
 468       else
 469         JCE->emitInt64((intptr_t)Jit.getOrEmitGlobalVariable(GV));
 470     } else {
 471       if (TD->getPointerSize() == sizeof(int32_t))
 472         JCE->emitInt32(0);
 473       else
 474         JCE->emitInt64(0);
 475     }
 476     // Asm->EOL("TypeInfo");
 477   }
 478
 479   // Emit the filter typeids.
 480   for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
 481     unsigned TypeID = FilterIds[j];
 482     JCE->emitULEB128Bytes(TypeID);
 483     //Asm->EOL("Filter TypeInfo index");
 484   }
 485
 486   JCE->emitAlignmentWithFill(4, 0);
 487
 488   return DwarfExceptionTable;
 489 }
 490
 491 unsigned char*
 492 JITDwarfEmitter::EmitCommonEHFrame(const Function* Personality) const {
 493   unsigned PointerSize = TD->getPointerSize();
 494   int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
 495           PointerSize : -PointerSize;
 496
 497   unsigned char* StartCommonPtr = (unsigned char*)JCE->getCurrentPCValue();
 498   // EH Common Frame header
 499   JCE->allocateSpace(4, 0);
 500   unsigned char* FrameCommonBeginPtr = (unsigned char*)JCE->getCurrentPCValue();
 501   JCE->emitInt32((int)0);
 502   JCE->emitByte(dwarf::DW_CIE_VERSION);
 503   JCE->emitString(Personality ? "zPLR" : "zR");
 504   JCE->emitULEB128Bytes(1);
 505   JCE->emitSLEB128Bytes(stackGrowth);
 506   JCE->emitByte(RI->getDwarfRegNum(RI->getRARegister(), true));
 507
 508   if (Personality) {
 509     // Augmentation Size: 3 small ULEBs of one byte each, and the personality
 510     // function which size is PointerSize.
 511     JCE->emitULEB128Bytes(3 + PointerSize);
 512
 513     // We set the encoding of the personality as direct encoding because we use
 514     // the function pointer. The encoding is not relative because the current
 515     // PC value may be bigger than the personality function pointer.
 516     if (PointerSize == 4) {
 517       JCE->emitByte(dwarf::DW_EH_PE_sdata4);
 518       JCE->emitInt32(((intptr_t)Jit.getPointerToGlobal(Personality)));
 519     } else {
 520       JCE->emitByte(dwarf::DW_EH_PE_sdata8);
 521       JCE->emitInt64(((intptr_t)Jit.getPointerToGlobal(Personality)));
 522     }
 523
 524     JCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
 525     JCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
 526   } else {
 527     JCE->emitULEB128Bytes(1);
 528     JCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
 529   }
 530
 531   std::vector<MachineMove> Moves;
 532   RI->getInitialFrameState(Moves);
 533   EmitFrameMoves(0, Moves);
 534
 535   JCE->emitAlignmentWithFill(PointerSize, dwarf::DW_CFA_nop);
 536
 537   JCE->emitInt32At((uintptr_t*)StartCommonPtr,
 538                    (uintptr_t)((unsigned char*)JCE->getCurrentPCValue() -
 539                                FrameCommonBeginPtr));
 540
 541   return StartCommonPtr;
 542 }
 543
 544
 545 unsigned char*
 546 JITDwarfEmitter::EmitEHFrame(const Function* Personality,
 547                              unsigned char* StartCommonPtr,
 548                              unsigned char* StartFunction,
 549                              unsigned char* EndFunction,
 550                              unsigned char* ExceptionTable) const {
 551   unsigned PointerSize = TD->getPointerSize();
 552
 553   // EH frame header.
 554   unsigned char* StartEHPtr = (unsigned char*)JCE->getCurrentPCValue();
 555   JCE->allocateSpace(4, 0);
 556   unsigned char* FrameBeginPtr = (unsigned char*)JCE->getCurrentPCValue();
 557   // FDE CIE Offset
 558   JCE->emitInt32(FrameBeginPtr - StartCommonPtr);
 559   JCE->emitInt32(StartFunction - (unsigned char*)JCE->getCurrentPCValue());
 560   JCE->emitInt32(EndFunction - StartFunction);
 561
 562   // If there is a personality and landing pads then point to the language
 563   // specific data area in the exception table.
 564   if (Personality) {
 565     JCE->emitULEB128Bytes(PointerSize == 4 ? 4 : 8);
 566
 567     if (PointerSize == 4) {
 568       if (!MMI->getLandingPads().empty())
 569         JCE->emitInt32(ExceptionTable-(unsigned char*)JCE->getCurrentPCValue());
 570       else
 571         JCE->emitInt32((int)0);
 572     } else {
 573       if (!MMI->getLandingPads().empty())
 574         JCE->emitInt64(ExceptionTable-(unsigned char*)JCE->getCurrentPCValue());
 575       else
 576         JCE->emitInt64((int)0);
 577     }
 578   } else {
 579     JCE->emitULEB128Bytes(0);
 580   }
 581
 582   // Indicate locations of function specific  callee saved registers in
 583   // frame.
 584   EmitFrameMoves((intptr_t)StartFunction, MMI->getFrameMoves());
 585
 586   JCE->emitAlignmentWithFill(PointerSize, dwarf::DW_CFA_nop);
 587
 588   // Indicate the size of the table
 589   JCE->emitInt32At((uintptr_t*)StartEHPtr,
 590                    (uintptr_t)((unsigned char*)JCE->getCurrentPCValue() -
 591                                StartEHPtr));
 592
 593   // Double zeroes for the unwind runtime
 594   if (PointerSize == 8) {
 595     JCE->emitInt64(0);
 596     JCE->emitInt64(0);
 597   } else {
 598     JCE->emitInt32(0);
 599     JCE->emitInt32(0);
 600   }
 601
 602   return StartEHPtr;
 603 }
 604
 605 unsigned JITDwarfEmitter::GetDwarfTableSizeInBytes(MachineFunction& F,
 606                                          JITCodeEmitter& jce,
 607                                          unsigned char* StartFunction,
 608                                          unsigned char* EndFunction) {
 609   const TargetMachine& TM = F.getTarget();
 610   TD = TM.getTargetData();
 611   needsIndirectEncoding = TM.getMCAsmInfo()->getNeedsIndirectEncoding();
 612   stackGrowthDirection = TM.getFrameInfo()->getStackGrowthDirection();
 613   RI = TM.getRegisterInfo();
 614   JCE = &jce;
 615   unsigned FinalSize = 0;
 616
 617   FinalSize += GetExceptionTableSizeInBytes(&F);
 618
 619   const std::vector<Function *> Personalities = MMI->getPersonalities();
 620   FinalSize +=
 621     GetCommonEHFrameSizeInBytes(Personalities[MMI->getPersonalityIndex()]);
 622
 623   FinalSize += GetEHFrameSizeInBytes(Personalities[MMI->getPersonalityIndex()],
 624                                      StartFunction);
 625
 626   return FinalSize;
 627 }
 628
 629 /// RoundUpToAlign - Add the specified alignment to FinalSize and returns
 630 /// the new value.
 631 static unsigned RoundUpToAlign(unsigned FinalSize, unsigned Alignment) {
 632   if (Alignment == 0) Alignment = 1;
 633   // Since we do not know where the buffer will be allocated, be pessimistic.
 634   return FinalSize + Alignment;
 635 }
 636
 637 unsigned
 638 JITDwarfEmitter::GetEHFrameSizeInBytes(const Function* Personality,
 639                                        unsigned char* StartFunction) const {
 640   unsigned PointerSize = TD->getPointerSize();
 641   unsigned FinalSize = 0;
 642   // EH frame header.
 643   FinalSize += PointerSize;
 644   // FDE CIE Offset
 645   FinalSize += 3 * PointerSize;
 646   // If there is a personality and landing pads then point to the language
 647   // specific data area in the exception table.
 648   if (Personality) {
 649     FinalSize += MCAsmInfo::getULEB128Size(4);
 650     FinalSize += PointerSize;
 651   } else {
 652     FinalSize += MCAsmInfo::getULEB128Size(0);
 653   }
 654
 655   // Indicate locations of function specific  callee saved registers in
 656   // frame.
 657   FinalSize += GetFrameMovesSizeInBytes((intptr_t)StartFunction,
 658                                         MMI->getFrameMoves());
 659
 660   FinalSize = RoundUpToAlign(FinalSize, 4);
 661
 662   // Double zeroes for the unwind runtime
 663   FinalSize += 2 * PointerSize;
 664
 665   return FinalSize;
 666 }
 667
 668 unsigned JITDwarfEmitter::GetCommonEHFrameSizeInBytes(const Function* Personality)
 669   const {
 670
 671   unsigned PointerSize = TD->getPointerSize();
 672   int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
 673           PointerSize : -PointerSize;
 674   unsigned FinalSize = 0;
 675   // EH Common Frame header
 676   FinalSize += PointerSize;
 677   FinalSize += 4;
 678   FinalSize += 1;
 679   FinalSize += Personality ? 5 : 3; // "zPLR" or "zR"
 680   FinalSize += MCAsmInfo::getULEB128Size(1);
 681   FinalSize += MCAsmInfo::getSLEB128Size(stackGrowth);
 682   FinalSize += 1;
 683
 684   if (Personality) {
 685     FinalSize += MCAsmInfo::getULEB128Size(7);
 686
 687     // Encoding
 688     FinalSize+= 1;
 689     //Personality
 690     FinalSize += PointerSize;
 691
 692     FinalSize += MCAsmInfo::getULEB128Size(dwarf::DW_EH_PE_pcrel);
 693     FinalSize += MCAsmInfo::getULEB128Size(dwarf::DW_EH_PE_pcrel);
 694
 695   } else {
 696     FinalSize += MCAsmInfo::getULEB128Size(1);
 697     FinalSize += MCAsmInfo::getULEB128Size(dwarf::DW_EH_PE_pcrel);
 698   }
 699
 700   std::vector<MachineMove> Moves;
 701   RI->getInitialFrameState(Moves);
 702   FinalSize += GetFrameMovesSizeInBytes(0, Moves);
 703   FinalSize = RoundUpToAlign(FinalSize, 4);
 704   return FinalSize;
 705 }
 706
 707 unsigned
 708 JITDwarfEmitter::GetFrameMovesSizeInBytes(intptr_t BaseLabelPtr,
 709                                   const std::vector<MachineMove> &Moves) const {
 710   unsigned PointerSize = TD->getPointerSize();
 711   int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
 712           PointerSize : -PointerSize;
 713   bool IsLocal = BaseLabelPtr;
 714   unsigned FinalSize = 0;
 715
 716   for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
 717     const MachineMove &Move = Moves[i];
 718     unsigned LabelID = Move.getLabelID();
 719
 720     if (LabelID) {
 721       LabelID = MMI->MappedLabel(LabelID);
 722
 723       // Throw out move if the label is invalid.
 724       if (!LabelID) continue;
 725     }
 726
 727     intptr_t LabelPtr = 0;
 728     if (LabelID) LabelPtr = JCE->getLabelAddress(LabelID);
 729
 730     const MachineLocation &Dst = Move.getDestination();
 731     const MachineLocation &Src = Move.getSource();
 732
 733     // Advance row if new location.
 734     if (BaseLabelPtr && LabelID && (BaseLabelPtr != LabelPtr || !IsLocal)) {
 735       FinalSize++;
 736       FinalSize += PointerSize;
 737       BaseLabelPtr = LabelPtr;
 738       IsLocal = true;
 739     }
 740
 741     // If advancing cfa.
 742     if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
 743       if (!Src.isReg()) {
 744         if (Src.getReg() == MachineLocation::VirtualFP) {
 745           ++FinalSize;
 746         } else {
 747           ++FinalSize;
 748           unsigned RegNum = RI->getDwarfRegNum(Src.getReg(), true);
 749           FinalSize += MCAsmInfo::getULEB128Size(RegNum);
 750         }
 751
 752         int Offset = -Src.getOffset();
 753
 754         FinalSize += MCAsmInfo::getULEB128Size(Offset);
 755       } else {
 756         llvm_unreachable("Machine move no supported yet.");
 757       }
 758     } else if (Src.isReg() &&
 759       Src.getReg() == MachineLocation::VirtualFP) {
 760       if (Dst.isReg()) {
 761         ++FinalSize;
 762         unsigned RegNum = RI->getDwarfRegNum(Dst.getReg(), true);
 763         FinalSize += MCAsmInfo::getULEB128Size(RegNum);
 764       } else {
 765         llvm_unreachable("Machine move no supported yet.");
 766       }
 767     } else {
 768       unsigned Reg = RI->getDwarfRegNum(Src.getReg(), true);
 769       int Offset = Dst.getOffset() / stackGrowth;
 770
 771       if (Offset < 0) {
 772         ++FinalSize;
 773         FinalSize += MCAsmInfo::getULEB128Size(Reg);
 774         FinalSize += MCAsmInfo::getSLEB128Size(Offset);
 775       } else if (Reg < 64) {
 776         ++FinalSize;
 777         FinalSize += MCAsmInfo::getULEB128Size(Offset);
 778       } else {
 779         ++FinalSize;
 780         FinalSize += MCAsmInfo::getULEB128Size(Reg);
 781         FinalSize += MCAsmInfo::getULEB128Size(Offset);
 782       }
 783     }
 784   }
 785   return FinalSize;
 786 }
 787
 788 unsigned
 789 JITDwarfEmitter::GetExceptionTableSizeInBytes(MachineFunction* MF) const {
 790   unsigned FinalSize = 0;
 791
 792   // Map all labels and get rid of any dead landing pads.
 793   MMI->TidyLandingPads();
 794
 795   const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
 796   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
 797   const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
 798   if (PadInfos.empty()) return 0;
 799
 800   // Sort the landing pads in order of their type ids.  This is used to fold
 801   // duplicate actions.
 802   SmallVector<const LandingPadInfo *, 64> LandingPads;
 803   LandingPads.reserve(PadInfos.size());
 804   for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
 805     LandingPads.push_back(&PadInfos[i]);
 806   std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
 807
 808   // Negative type ids index into FilterIds, positive type ids index into
 809   // TypeInfos.  The value written for a positive type id is just the type
 810   // id itself.  For a negative type id, however, the value written is the
 811   // (negative) byte offset of the corresponding FilterIds entry.  The byte
 812   // offset is usually equal to the type id, because the FilterIds entries
 813   // are written using a variable width encoding which outputs one byte per
 814   // entry as long as the value written is not too large, but can differ.
 815   // This kind of complication does not occur for positive type ids because
 816   // type infos are output using a fixed width encoding.
 817   // FilterOffsets[i] holds the byte offset corresponding to FilterIds[i].
 818   SmallVector<int, 16> FilterOffsets;
 819   FilterOffsets.reserve(FilterIds.size());
 820   int Offset = -1;
 821   for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
 822     E = FilterIds.end(); I != E; ++I) {
 823     FilterOffsets.push_back(Offset);
 824     Offset -= MCAsmInfo::getULEB128Size(*I);
 825   }
 826
 827   // Compute the actions table and gather the first action index for each
 828   // landing pad site.
 829   SmallVector<ActionEntry, 32> Actions;
 830   SmallVector<unsigned, 64> FirstActions;
 831   FirstActions.reserve(LandingPads.size());
 832
 833   int FirstAction = 0;
 834   unsigned SizeActions = 0;
 835   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
 836     const LandingPadInfo *LP = LandingPads[i];
 837     const std::vector<int> &TypeIds = LP->TypeIds;
 838     const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
 839     unsigned SizeSiteActions = 0;
 840
 841     if (NumShared < TypeIds.size()) {
 842       unsigned SizeAction = 0;
 843       ActionEntry *PrevAction = 0;
 844
 845       if (NumShared) {
 846         const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
 847         assert(Actions.size());
 848         PrevAction = &Actions.back();
 849         SizeAction = MCAsmInfo::getSLEB128Size(PrevAction->NextAction) +
 850           MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
 851         for (unsigned j = NumShared; j != SizePrevIds; ++j) {
 852           SizeAction -= MCAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
 853           SizeAction += -PrevAction->NextAction;
 854           PrevAction = PrevAction->Previous;
 855         }
 856       }
 857
 858       // Compute the actions.
 859       for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
 860         int TypeID = TypeIds[I];
 861         assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
 862         int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
 863         unsigned SizeTypeID = MCAsmInfo::getSLEB128Size(ValueForTypeID);
 864
 865         int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
 866         SizeAction = SizeTypeID + MCAsmInfo::getSLEB128Size(NextAction);
 867         SizeSiteActions += SizeAction;
 868
 869         ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
 870         Actions.push_back(Action);
 871
 872         PrevAction = &Actions.back();
 873       }
 874
 875       // Record the first action of the landing pad site.
 876       FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
 877     } // else identical - re-use previous FirstAction
 878
 879     FirstActions.push_back(FirstAction);
 880
 881     // Compute this sites contribution to size.
 882     SizeActions += SizeSiteActions;
 883   }
 884
 885   // Compute the call-site table.  Entries must be ordered by address.
 886   SmallVector<CallSiteEntry, 64> CallSites;
 887
 888   RangeMapType PadMap;
 889   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
 890     const LandingPadInfo *LandingPad = LandingPads[i];
 891     for (unsigned j=0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
 892       unsigned BeginLabel = LandingPad->BeginLabels[j];
 893       assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
 894       PadRange P = { i, j };
 895       PadMap[BeginLabel] = P;
 896     }
 897   }
 898
 899   bool MayThrow = false;
 900   unsigned LastLabel = 0;
 901   for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
 902         I != E; ++I) {
 903     for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
 904           MI != E; ++MI) {
 905       if (!MI->isLabel()) {
 906         MayThrow |= MI->getDesc().isCall();
 907         continue;
 908       }
 909
 910       unsigned BeginLabel = MI->getOperand(0).getImm();
 911       assert(BeginLabel && "Invalid label!");
 912
 913       if (BeginLabel == LastLabel)
 914         MayThrow = false;
 915
 916       RangeMapType::iterator L = PadMap.find(BeginLabel);
 917
 918       if (L == PadMap.end())
 919         continue;
 920
 921       PadRange P = L->second;
 922       const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
 923
 924       assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
 925               "Inconsistent landing pad map!");
 926
 927       // If some instruction between the previous try-range and this one may
 928       // throw, create a call-site entry with no landing pad for the region
 929       // between the try-ranges.
 930       if (MayThrow) {
 931         CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
 932         CallSites.push_back(Site);
 933       }
 934
 935       LastLabel = LandingPad->EndLabels[P.RangeIndex];
 936       CallSiteEntry Site = {BeginLabel, LastLabel,
 937         LandingPad->LandingPadLabel, FirstActions[P.PadIndex]};
 938
 939       assert(Site.BeginLabel && Site.EndLabel && Site.PadLabel &&
 940               "Invalid landing pad!");
 941
 942       // Try to merge with the previous call-site.
 943       if (CallSites.size()) {
 944         CallSiteEntry &Prev = CallSites.back();
 945         if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
 946           // Extend the range of the previous entry.
 947           Prev.EndLabel = Site.EndLabel;
 948           continue;
 949         }
 950       }
 951
 952       // Otherwise, create a new call-site.
 953       CallSites.push_back(Site);
 954     }
 955   }
 956   // If some instruction between the previous try-range and the end of the
 957   // function may throw, create a call-site entry with no landing pad for the
 958   // region following the try-range.
 959   if (MayThrow) {
 960     CallSiteEntry Site = {LastLabel, 0, 0, 0};
 961     CallSites.push_back(Site);
 962   }
 963
 964   // Final tallies.
 965   unsigned SizeSites = CallSites.size() * (sizeof(int32_t) + // Site start.
 966                                             sizeof(int32_t) + // Site length.
 967                                             sizeof(int32_t)); // Landing pad.
 968   for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
 969     SizeSites += MCAsmInfo::getULEB128Size(CallSites[i].Action);
 970
 971   unsigned SizeTypes = TypeInfos.size() * TD->getPointerSize();
 972
 973   unsigned TypeOffset = sizeof(int8_t) + // Call site format
 974                         // Call-site table length
 975                         MCAsmInfo::getULEB128Size(SizeSites) +
 976                         SizeSites + SizeActions + SizeTypes;
 977
 978   unsigned TotalSize = sizeof(int8_t) + // LPStart format
 979                        sizeof(int8_t) + // TType format
 980                        MCAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
 981                        TypeOffset;
 982
 983   unsigned SizeAlign = (4 - TotalSize) & 3;
 984
 985   // Begin the exception table.
 986   FinalSize = RoundUpToAlign(FinalSize, 4);
 987   for (unsigned i = 0; i != SizeAlign; ++i) {
 988     ++FinalSize;
 989   }
 990
 991   unsigned PointerSize = TD->getPointerSize();
 992
 993   // Emit the header.
 994   ++FinalSize;
 995   // Asm->EOL("LPStart format (DW_EH_PE_omit)");
 996   ++FinalSize;
 997   // Asm->EOL("TType format (DW_EH_PE_absptr)");
 998   ++FinalSize;
 999   // Asm->EOL("TType base offset");
1000   ++FinalSize;
1001   // Asm->EOL("Call site format (DW_EH_PE_udata4)");
1002   ++FinalSize;
1003   // Asm->EOL("Call-site table length");
1004
1005   // Emit the landing pad site information.
1006   for (unsigned i = 0; i < CallSites.size(); ++i) {
1007     CallSiteEntry &S = CallSites[i];
1008
1009     // Asm->EOL("Region start");
1010     FinalSize += PointerSize;
1011
1012     //Asm->EOL("Region length");
1013     FinalSize += PointerSize;
1014
1015     // Asm->EOL("Landing pad");
1016     FinalSize += PointerSize;
1017
1018     FinalSize += MCAsmInfo::getULEB128Size(S.Action);
1019     // Asm->EOL("Action");
1020   }
1021
1022   // Emit the actions.
1023   for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
1024     ActionEntry &Action = Actions[I];
1025
1026     //Asm->EOL("TypeInfo index");
1027     FinalSize += MCAsmInfo::getSLEB128Size(Action.ValueForTypeID);
1028     //Asm->EOL("Next action");
1029     FinalSize += MCAsmInfo::getSLEB128Size(Action.NextAction);
1030   }
1031
1032   // Emit the type ids.
1033   for (unsigned M = TypeInfos.size(); M; --M) {
1034     // Asm->EOL("TypeInfo");
1035     FinalSize += PointerSize;
1036   }
1037
1038   // Emit the filter typeids.
1039   for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
1040     unsigned TypeID = FilterIds[j];
1041     FinalSize += MCAsmInfo::getULEB128Size(TypeID);
1042     //Asm->EOL("Filter TypeInfo index");
1043   }
1044
1045   FinalSize = RoundUpToAlign(FinalSize, 4);
1046
1047   return FinalSize;
1048 }