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/MachineCodeEmitter.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/Target/TargetAsmInfo.h"
  25 #include "llvm/Target/TargetData.h"
  26 #include "llvm/Target/TargetInstrInfo.h"
  27 #include "llvm/Target/TargetFrameInfo.h"
  28 #include "llvm/Target/TargetMachine.h"
  29 #include "llvm/Target/TargetRegisterInfo.h"
  30
  31 using namespace llvm;
  32
  33 JITDwarfEmitter::JITDwarfEmitter(JIT& theJit) : Jit(theJit) {}
  34
  35
  36 unsigned char* JITDwarfEmitter::EmitDwarfTable(MachineFunction& F,
  37                                                MachineCodeEmitter& mce,
  38                                                unsigned char* StartFunction,
  39                                                unsigned char* EndFunction) {
  40   const TargetMachine& TM = F.getTarget();
  41   TD = TM.getTargetData();
  42   needsIndirectEncoding = TM.getTargetAsmInfo()->getNeedsIndirectEncoding();
  43   stackGrowthDirection = TM.getFrameInfo()->getStackGrowthDirection();
  44   RI = TM.getRegisterInfo();
  45   MCE = &mce;
  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 = MCE->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       MCE->emitByte(dwarf::DW_CFA_advance_loc4);
  92       MCE->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           MCE->emitByte(dwarf::DW_CFA_def_cfa_offset);
 104         } else {
 105           MCE->emitByte(dwarf::DW_CFA_def_cfa);
 106           MCE->emitULEB128Bytes(RI->getDwarfRegNum(Src.getReg(), true));
 107         }
 108
 109         int Offset = -Src.getOffset();
 110
 111         MCE->emitULEB128Bytes(Offset);
 112       } else {
 113         assert(0 && "Machine move no supported yet.");
 114       }
 115     } else if (Src.isReg() &&
 116       Src.getReg() == MachineLocation::VirtualFP) {
 117       if (Dst.isReg()) {
 118         MCE->emitByte(dwarf::DW_CFA_def_cfa_register);
 119         MCE->emitULEB128Bytes(RI->getDwarfRegNum(Dst.getReg(), true));
 120       } else {
 121         assert(0 && "Machine move no supported yet.");
 122       }
 123     } else {
 124       unsigned Reg = RI->getDwarfRegNum(Src.getReg(), true);
 125       int Offset = Dst.getOffset() / stackGrowth;
 126
 127       if (Offset < 0) {
 128         MCE->emitByte(dwarf::DW_CFA_offset_extended_sf);
 129         MCE->emitULEB128Bytes(Reg);
 130         MCE->emitSLEB128Bytes(Offset);
 131       } else if (Reg < 64) {
 132         MCE->emitByte(dwarf::DW_CFA_offset + Reg);
 133         MCE->emitULEB128Bytes(Offset);
 134       } else {
 135         MCE->emitByte(dwarf::DW_CFA_offset_extended);
 136         MCE->emitULEB128Bytes(Reg);
 137         MCE->emitULEB128Bytes(Offset);
 138       }
 139     }
 140   }
 141 }
 142
 143 /// SharedTypeIds - How many leading type ids two landing pads have in common.
 144 static unsigned SharedTypeIds(const LandingPadInfo *L,
 145                               const LandingPadInfo *R) {
 146   const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
 147   unsigned LSize = LIds.size(), RSize = RIds.size();
 148   unsigned MinSize = LSize < RSize ? LSize : RSize;
 149   unsigned Count = 0;
 150
 151   for (; Count != MinSize; ++Count)
 152     if (LIds[Count] != RIds[Count])
 153       return Count;
 154
 155   return Count;
 156 }
 157
 158
 159 /// PadLT - Order landing pads lexicographically by type id.
 160 static bool PadLT(const LandingPadInfo *L, const LandingPadInfo *R) {
 161   const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
 162   unsigned LSize = LIds.size(), RSize = RIds.size();
 163   unsigned MinSize = LSize < RSize ? LSize : RSize;
 164
 165   for (unsigned i = 0; i != MinSize; ++i)
 166     if (LIds[i] != RIds[i])
 167       return LIds[i] < RIds[i];
 168
 169   return LSize < RSize;
 170 }
 171
 172 namespace {
 173
 174 struct KeyInfo {
 175   static inline unsigned getEmptyKey() { return -1U; }
 176   static inline unsigned getTombstoneKey() { return -2U; }
 177   static unsigned getHashValue(const unsigned &Key) { return Key; }
 178   static bool isEqual(unsigned LHS, unsigned RHS) { return LHS == RHS; }
 179   static bool isPod() { return true; }
 180 };
 181
 182 /// ActionEntry - Structure describing an entry in the actions table.
 183 struct ActionEntry {
 184   int ValueForTypeID; // The value to write - may not be equal to the type id.
 185   int NextAction;
 186   struct ActionEntry *Previous;
 187 };
 188
 189 /// PadRange - Structure holding a try-range and the associated landing pad.
 190 struct PadRange {
 191   // The index of the landing pad.
 192   unsigned PadIndex;
 193   // The index of the begin and end labels in the landing pad's label lists.
 194   unsigned RangeIndex;
 195 };
 196
 197 typedef DenseMap<unsigned, PadRange, KeyInfo> RangeMapType;
 198
 199 /// CallSiteEntry - Structure describing an entry in the call-site table.
 200 struct CallSiteEntry {
 201   unsigned BeginLabel; // zero indicates the start of the function.
 202   unsigned EndLabel;   // zero indicates the end of the function.
 203   unsigned PadLabel;   // zero indicates that there is no landing pad.
 204   unsigned Action;
 205 };
 206
 207 }
 208
 209 unsigned char* JITDwarfEmitter::EmitExceptionTable(MachineFunction* MF,
 210                                          unsigned char* StartFunction,
 211                                          unsigned char* EndFunction) const {
 212   // Map all labels and get rid of any dead landing pads.
 213   MMI->TidyLandingPads();
 214
 215   const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
 216   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
 217   const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
 218   if (PadInfos.empty()) return 0;
 219
 220   // Sort the landing pads in order of their type ids.  This is used to fold
 221   // duplicate actions.
 222   SmallVector<const LandingPadInfo *, 64> LandingPads;
 223   LandingPads.reserve(PadInfos.size());
 224   for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
 225     LandingPads.push_back(&PadInfos[i]);
 226   std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
 227
 228   // Negative type ids index into FilterIds, positive type ids index into
 229   // TypeInfos.  The value written for a positive type id is just the type
 230   // id itself.  For a negative type id, however, the value written is the
 231   // (negative) byte offset of the corresponding FilterIds entry.  The byte
 232   // offset is usually equal to the type id, because the FilterIds entries
 233   // are written using a variable width encoding which outputs one byte per
 234   // entry as long as the value written is not too large, but can differ.
 235   // This kind of complication does not occur for positive type ids because
 236   // type infos are output using a fixed width encoding.
 237   // FilterOffsets[i] holds the byte offset corresponding to FilterIds[i].
 238   SmallVector<int, 16> FilterOffsets;
 239   FilterOffsets.reserve(FilterIds.size());
 240   int Offset = -1;
 241   for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
 242     E = FilterIds.end(); I != E; ++I) {
 243     FilterOffsets.push_back(Offset);
 244     Offset -= TargetAsmInfo::getULEB128Size(*I);
 245   }
 246
 247   // Compute the actions table and gather the first action index for each
 248   // landing pad site.
 249   SmallVector<ActionEntry, 32> Actions;
 250   SmallVector<unsigned, 64> FirstActions;
 251   FirstActions.reserve(LandingPads.size());
 252
 253   int FirstAction = 0;
 254   unsigned SizeActions = 0;
 255   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
 256     const LandingPadInfo *LP = LandingPads[i];
 257     const std::vector<int> &TypeIds = LP->TypeIds;
 258     const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
 259     unsigned SizeSiteActions = 0;
 260
 261     if (NumShared < TypeIds.size()) {
 262       unsigned SizeAction = 0;
 263       ActionEntry *PrevAction = 0;
 264
 265       if (NumShared) {
 266         const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
 267         assert(Actions.size());
 268         PrevAction = &Actions.back();
 269         SizeAction = TargetAsmInfo::getSLEB128Size(PrevAction->NextAction) +
 270           TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
 271         for (unsigned j = NumShared; j != SizePrevIds; ++j) {
 272           SizeAction -= TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
 273           SizeAction += -PrevAction->NextAction;
 274           PrevAction = PrevAction->Previous;
 275         }
 276       }
 277
 278       // Compute the actions.
 279       for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
 280         int TypeID = TypeIds[I];
 281         assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
 282         int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
 283         unsigned SizeTypeID = TargetAsmInfo::getSLEB128Size(ValueForTypeID);
 284
 285         int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
 286         SizeAction = SizeTypeID + TargetAsmInfo::getSLEB128Size(NextAction);
 287         SizeSiteActions += SizeAction;
 288
 289         ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
 290         Actions.push_back(Action);
 291
 292         PrevAction = &Actions.back();
 293       }
 294
 295       // Record the first action of the landing pad site.
 296       FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
 297     } // else identical - re-use previous FirstAction
 298
 299     FirstActions.push_back(FirstAction);
 300
 301     // Compute this sites contribution to size.
 302     SizeActions += SizeSiteActions;
 303   }
 304
 305   // Compute the call-site table.  Entries must be ordered by address.
 306   SmallVector<CallSiteEntry, 64> CallSites;
 307
 308   RangeMapType PadMap;
 309   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
 310     const LandingPadInfo *LandingPad = LandingPads[i];
 311     for (unsigned j=0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
 312       unsigned BeginLabel = LandingPad->BeginLabels[j];
 313       assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
 314       PadRange P = { i, j };
 315       PadMap[BeginLabel] = P;
 316     }
 317   }
 318
 319   bool MayThrow = false;
 320   unsigned LastLabel = 0;
 321   for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
 322         I != E; ++I) {
 323     for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
 324           MI != E; ++MI) {
 325       if (!MI->isLabel()) {
 326         MayThrow |= MI->getDesc().isCall();
 327         continue;
 328       }
 329
 330       unsigned BeginLabel = MI->getOperand(0).getImm();
 331       assert(BeginLabel && "Invalid label!");
 332
 333       if (BeginLabel == LastLabel)
 334         MayThrow = false;
 335
 336       RangeMapType::iterator L = PadMap.find(BeginLabel);
 337
 338       if (L == PadMap.end())
 339         continue;
 340
 341       PadRange P = L->second;
 342       const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
 343
 344       assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
 345               "Inconsistent landing pad map!");
 346
 347       // If some instruction between the previous try-range and this one may
 348       // throw, create a call-site entry with no landing pad for the region
 349       // between the try-ranges.
 350       if (MayThrow) {
 351         CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
 352         CallSites.push_back(Site);
 353       }
 354
 355       LastLabel = LandingPad->EndLabels[P.RangeIndex];
 356       CallSiteEntry Site = {BeginLabel, LastLabel,
 357         LandingPad->LandingPadLabel, FirstActions[P.PadIndex]};
 358
 359       assert(Site.BeginLabel && Site.EndLabel && Site.PadLabel &&
 360               "Invalid landing pad!");
 361
 362       // Try to merge with the previous call-site.
 363       if (CallSites.size()) {
 364         CallSiteEntry &Prev = CallSites.back();
 365         if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
 366           // Extend the range of the previous entry.
 367           Prev.EndLabel = Site.EndLabel;
 368           continue;
 369         }
 370       }
 371
 372       // Otherwise, create a new call-site.
 373       CallSites.push_back(Site);
 374     }
 375   }
 376   // If some instruction between the previous try-range and the end of the
 377   // function may throw, create a call-site entry with no landing pad for the
 378   // region following the try-range.
 379   if (MayThrow) {
 380     CallSiteEntry Site = {LastLabel, 0, 0, 0};
 381     CallSites.push_back(Site);
 382   }
 383
 384   // Final tallies.
 385   unsigned SizeSites = CallSites.size() * (sizeof(int32_t) + // Site start.
 386                                             sizeof(int32_t) + // Site length.
 387                                             sizeof(int32_t)); // Landing pad.
 388   for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
 389     SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
 390
 391   unsigned SizeTypes = TypeInfos.size() * TD->getPointerSize();
 392
 393   unsigned TypeOffset = sizeof(int8_t) + // Call site format
 394                         // Call-site table length
 395                         TargetAsmInfo::getULEB128Size(SizeSites) +
 396                         SizeSites + SizeActions + SizeTypes;
 397
 398   unsigned TotalSize = sizeof(int8_t) + // LPStart format
 399                        sizeof(int8_t) + // TType format
 400                        TargetAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
 401                        TypeOffset;
 402
 403   unsigned SizeAlign = (4 - TotalSize) & 3;
 404
 405   // Begin the exception table.
 406   MCE->emitAlignment(4);
 407   for (unsigned i = 0; i != SizeAlign; ++i) {
 408     MCE->emitByte(0);
 409     // Asm->EOL("Padding");
 410   }
 411
 412   unsigned char* DwarfExceptionTable = (unsigned char*)MCE->getCurrentPCValue();
 413
 414   // Emit the header.
 415   MCE->emitByte(dwarf::DW_EH_PE_omit);
 416   // Asm->EOL("LPStart format (DW_EH_PE_omit)");
 417   MCE->emitByte(dwarf::DW_EH_PE_absptr);
 418   // Asm->EOL("TType format (DW_EH_PE_absptr)");
 419   MCE->emitULEB128Bytes(TypeOffset);
 420   // Asm->EOL("TType base offset");
 421   MCE->emitByte(dwarf::DW_EH_PE_udata4);
 422   // Asm->EOL("Call site format (DW_EH_PE_udata4)");
 423   MCE->emitULEB128Bytes(SizeSites);
 424   // Asm->EOL("Call-site table length");
 425
 426   // Emit the landing pad site information.
 427   for (unsigned i = 0; i < CallSites.size(); ++i) {
 428     CallSiteEntry &S = CallSites[i];
 429     intptr_t BeginLabelPtr = 0;
 430     intptr_t EndLabelPtr = 0;
 431
 432     if (!S.BeginLabel) {
 433       BeginLabelPtr = (intptr_t)StartFunction;
 434       MCE->emitInt32(0);
 435     } else {
 436       BeginLabelPtr = MCE->getLabelAddress(S.BeginLabel);
 437       MCE->emitInt32(BeginLabelPtr - (intptr_t)StartFunction);
 438     }
 439
 440     // Asm->EOL("Region start");
 441
 442     if (!S.EndLabel) {
 443       EndLabelPtr = (intptr_t)EndFunction;
 444       MCE->emitInt32((intptr_t)EndFunction - BeginLabelPtr);
 445     } else {
 446       EndLabelPtr = MCE->getLabelAddress(S.EndLabel);
 447       MCE->emitInt32(EndLabelPtr - BeginLabelPtr);
 448     }
 449     //Asm->EOL("Region length");
 450
 451     if (!S.PadLabel) {
 452       MCE->emitInt32(0);
 453     } else {
 454       unsigned PadLabelPtr = MCE->getLabelAddress(S.PadLabel);
 455       MCE->emitInt32(PadLabelPtr - (intptr_t)StartFunction);
 456     }
 457     // Asm->EOL("Landing pad");
 458
 459     MCE->emitULEB128Bytes(S.Action);
 460     // Asm->EOL("Action");
 461   }
 462
 463   // Emit the actions.
 464   for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
 465     ActionEntry &Action = Actions[I];
 466
 467     MCE->emitSLEB128Bytes(Action.ValueForTypeID);
 468     //Asm->EOL("TypeInfo index");
 469     MCE->emitSLEB128Bytes(Action.NextAction);
 470     //Asm->EOL("Next action");
 471   }
 472
 473   // Emit the type ids.
 474   for (unsigned M = TypeInfos.size(); M; --M) {
 475     GlobalVariable *GV = TypeInfos[M - 1];
 476
 477     if (GV) {
 478       if (TD->getPointerSize() == sizeof(int32_t)) {
 479         MCE->emitInt32((intptr_t)Jit.getOrEmitGlobalVariable(GV));
 480       } else {
 481         MCE->emitInt64((intptr_t)Jit.getOrEmitGlobalVariable(GV));
 482       }
 483     } else {
 484       if (TD->getPointerSize() == sizeof(int32_t))
 485         MCE->emitInt32(0);
 486       else
 487         MCE->emitInt64(0);
 488     }
 489     // Asm->EOL("TypeInfo");
 490   }
 491
 492   // Emit the filter typeids.
 493   for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
 494     unsigned TypeID = FilterIds[j];
 495     MCE->emitULEB128Bytes(TypeID);
 496     //Asm->EOL("Filter TypeInfo index");
 497   }
 498
 499   MCE->emitAlignment(4);
 500
 501   return DwarfExceptionTable;
 502 }
 503
 504 unsigned char*
 505 JITDwarfEmitter::EmitCommonEHFrame(const Function* Personality) const {
 506   unsigned PointerSize = TD->getPointerSize();
 507   int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
 508           PointerSize : -PointerSize;
 509
 510   unsigned char* StartCommonPtr = (unsigned char*)MCE->getCurrentPCValue();
 511   // EH Common Frame header
 512   MCE->allocateSpace(4, 0);
 513   unsigned char* FrameCommonBeginPtr = (unsigned char*)MCE->getCurrentPCValue();
 514   MCE->emitInt32((int)0);
 515   MCE->emitByte(dwarf::DW_CIE_VERSION);
 516   MCE->emitString(Personality ? "zPLR" : "zR");
 517   MCE->emitULEB128Bytes(1);
 518   MCE->emitSLEB128Bytes(stackGrowth);
 519   MCE->emitByte(RI->getDwarfRegNum(RI->getRARegister(), true));
 520
 521   if (Personality) {
 522     // Augmentation Size: 3 small ULEBs of one byte each, and the personality
 523     // function which size is PointerSize.
 524     MCE->emitULEB128Bytes(3 + PointerSize);
 525
 526     // We set the encoding of the personality as direct encoding because we use
 527     // the function pointer. The encoding is not relative because the current
 528     // PC value may be bigger than the personality function pointer.
 529     if (PointerSize == 4) {
 530       MCE->emitByte(dwarf::DW_EH_PE_sdata4);
 531       MCE->emitInt32(((intptr_t)Jit.getPointerToGlobal(Personality)));
 532     } else {
 533       MCE->emitByte(dwarf::DW_EH_PE_sdata8);
 534       MCE->emitInt64(((intptr_t)Jit.getPointerToGlobal(Personality)));
 535     }
 536
 537     MCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
 538     MCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
 539
 540   } else {
 541     MCE->emitULEB128Bytes(1);
 542     MCE->emitULEB128Bytes(dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4);
 543   }
 544
 545   std::vector<MachineMove> Moves;
 546   RI->getInitialFrameState(Moves);
 547   EmitFrameMoves(0, Moves);
 548   MCE->emitAlignment(PointerSize);
 549
 550   MCE->emitInt32At((uintptr_t*)StartCommonPtr,
 551               (uintptr_t)((unsigned char*)MCE->getCurrentPCValue() -
 552                           FrameCommonBeginPtr));
 553
 554   return StartCommonPtr;
 555 }
 556
 557
 558 unsigned char*
 559 JITDwarfEmitter::EmitEHFrame(const Function* Personality,
 560                              unsigned char* StartCommonPtr,
 561                              unsigned char* StartFunction,
 562                              unsigned char* EndFunction,
 563                              unsigned char* ExceptionTable) const {
 564   unsigned PointerSize = TD->getPointerSize();
 565
 566   // EH frame header.
 567   unsigned char* StartEHPtr = (unsigned char*)MCE->getCurrentPCValue();
 568   MCE->allocateSpace(4, 0);
 569   unsigned char* FrameBeginPtr = (unsigned char*)MCE->getCurrentPCValue();
 570   // FDE CIE Offset
 571   MCE->emitInt32(FrameBeginPtr - StartCommonPtr);
 572   MCE->emitInt32(StartFunction - (unsigned char*)MCE->getCurrentPCValue());
 573   MCE->emitInt32(EndFunction - StartFunction);
 574
 575   // If there is a personality and landing pads then point to the language
 576   // specific data area in the exception table.
 577   if (MMI->getPersonalityIndex()) {
 578     MCE->emitULEB128Bytes(4);
 579
 580     if (!MMI->getLandingPads().empty()) {
 581       MCE->emitInt32(ExceptionTable - (unsigned char*)MCE->getCurrentPCValue());
 582     } else {
 583       MCE->emitInt32((int)0);
 584     }
 585   } else {
 586     MCE->emitULEB128Bytes(0);
 587   }
 588
 589   // Indicate locations of function specific  callee saved registers in
 590   // frame.
 591   EmitFrameMoves((intptr_t)StartFunction, MMI->getFrameMoves());
 592
 593   MCE->emitAlignment(PointerSize);
 594
 595   // Indicate the size of the table
 596   MCE->emitInt32At((uintptr_t*)StartEHPtr,
 597               (uintptr_t)((unsigned char*)MCE->getCurrentPCValue() -
 598                           StartEHPtr));
 599
 600   // Double zeroes for the unwind runtime
 601   if (PointerSize == 8) {
 602     MCE->emitInt64(0);
 603     MCE->emitInt64(0);
 604   } else {
 605     MCE->emitInt32(0);
 606     MCE->emitInt32(0);
 607   }
 608
 609
 610   return StartEHPtr;
 611 }
 612
 613 unsigned JITDwarfEmitter::GetDwarfTableSizeInBytes(MachineFunction& F,
 614                                          MachineCodeEmitter& mce,
 615                                          unsigned char* StartFunction,
 616                                          unsigned char* EndFunction) {
 617   const TargetMachine& TM = F.getTarget();
 618   TD = TM.getTargetData();
 619   needsIndirectEncoding = TM.getTargetAsmInfo()->getNeedsIndirectEncoding();
 620   stackGrowthDirection = TM.getFrameInfo()->getStackGrowthDirection();
 621   RI = TM.getRegisterInfo();
 622   MCE = &mce;
 623   unsigned FinalSize = 0;
 624
 625   FinalSize += GetExceptionTableSizeInBytes(&F);
 626
 627   const std::vector<Function *> Personalities = MMI->getPersonalities();
 628   FinalSize +=
 629     GetCommonEHFrameSizeInBytes(Personalities[MMI->getPersonalityIndex()]);
 630
 631   FinalSize += GetEHFrameSizeInBytes(Personalities[MMI->getPersonalityIndex()],
 632                                      StartFunction);
 633
 634   return FinalSize;
 635 }
 636
 637 /// RoundUpToAlign - Add the specified alignment to FinalSize and returns
 638 /// the new value.
 639 static unsigned RoundUpToAlign(unsigned FinalSize, unsigned Alignment) {
 640   if (Alignment == 0) Alignment = 1;
 641   // Since we do not know where the buffer will be allocated, be pessimistic.
 642   return FinalSize + Alignment;
 643 }
 644
 645 unsigned
 646 JITDwarfEmitter::GetEHFrameSizeInBytes(const Function* Personality,
 647                                        unsigned char* StartFunction) const {
 648   unsigned PointerSize = TD->getPointerSize();
 649   unsigned FinalSize = 0;
 650   // EH frame header.
 651   FinalSize += PointerSize;
 652   // FDE CIE Offset
 653   FinalSize += 3 * PointerSize;
 654   // If there is a personality and landing pads then point to the language
 655   // specific data area in the exception table.
 656   if (MMI->getPersonalityIndex()) {
 657     FinalSize += TargetAsmInfo::getULEB128Size(4);
 658     FinalSize += PointerSize;
 659   } else {
 660     FinalSize += TargetAsmInfo::getULEB128Size(0);
 661   }
 662
 663   // Indicate locations of function specific  callee saved registers in
 664   // frame.
 665   FinalSize += GetFrameMovesSizeInBytes((intptr_t)StartFunction,
 666                                         MMI->getFrameMoves());
 667
 668   FinalSize = RoundUpToAlign(FinalSize, 4);
 669
 670   // Double zeroes for the unwind runtime
 671   FinalSize += 2 * PointerSize;
 672
 673   return FinalSize;
 674 }
 675
 676 unsigned JITDwarfEmitter::GetCommonEHFrameSizeInBytes(const Function* Personality)
 677   const {
 678
 679   unsigned PointerSize = TD->getPointerSize();
 680   int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
 681           PointerSize : -PointerSize;
 682   unsigned FinalSize = 0;
 683   // EH Common Frame header
 684   FinalSize += PointerSize;
 685   FinalSize += 4;
 686   FinalSize += 1;
 687   FinalSize += Personality ? 5 : 3; // "zPLR" or "zR"
 688   FinalSize += TargetAsmInfo::getULEB128Size(1);
 689   FinalSize += TargetAsmInfo::getSLEB128Size(stackGrowth);
 690   FinalSize += 1;
 691
 692   if (Personality) {
 693     FinalSize += TargetAsmInfo::getULEB128Size(7);
 694
 695     // Encoding
 696     FinalSize+= 1;
 697     //Personality
 698     FinalSize += PointerSize;
 699
 700     FinalSize += TargetAsmInfo::getULEB128Size(dwarf::DW_EH_PE_pcrel);
 701     FinalSize += TargetAsmInfo::getULEB128Size(dwarf::DW_EH_PE_pcrel);
 702
 703   } else {
 704     FinalSize += TargetAsmInfo::getULEB128Size(1);
 705     FinalSize += TargetAsmInfo::getULEB128Size(dwarf::DW_EH_PE_pcrel);
 706   }
 707
 708   std::vector<MachineMove> Moves;
 709   RI->getInitialFrameState(Moves);
 710   FinalSize += GetFrameMovesSizeInBytes(0, Moves);
 711   FinalSize = RoundUpToAlign(FinalSize, 4);
 712   return FinalSize;
 713 }
 714
 715 unsigned
 716 JITDwarfEmitter::GetFrameMovesSizeInBytes(intptr_t BaseLabelPtr,
 717                                   const std::vector<MachineMove> &Moves) const {
 718   unsigned PointerSize = TD->getPointerSize();
 719   int stackGrowth = stackGrowthDirection == TargetFrameInfo::StackGrowsUp ?
 720           PointerSize : -PointerSize;
 721   bool IsLocal = BaseLabelPtr;
 722   unsigned FinalSize = 0;
 723
 724   for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
 725     const MachineMove &Move = Moves[i];
 726     unsigned LabelID = Move.getLabelID();
 727
 728     if (LabelID) {
 729       LabelID = MMI->MappedLabel(LabelID);
 730
 731       // Throw out move if the label is invalid.
 732       if (!LabelID) continue;
 733     }
 734
 735     intptr_t LabelPtr = 0;
 736     if (LabelID) LabelPtr = MCE->getLabelAddress(LabelID);
 737
 738     const MachineLocation &Dst = Move.getDestination();
 739     const MachineLocation &Src = Move.getSource();
 740
 741     // Advance row if new location.
 742     if (BaseLabelPtr && LabelID && (BaseLabelPtr != LabelPtr || !IsLocal)) {
 743       FinalSize++;
 744       FinalSize += PointerSize;
 745       BaseLabelPtr = LabelPtr;
 746       IsLocal = true;
 747     }
 748
 749     // If advancing cfa.
 750     if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
 751       if (!Src.isReg()) {
 752         if (Src.getReg() == MachineLocation::VirtualFP) {
 753           ++FinalSize;
 754         } else {
 755           ++FinalSize;
 756           unsigned RegNum = RI->getDwarfRegNum(Src.getReg(), true);
 757           FinalSize += TargetAsmInfo::getULEB128Size(RegNum);
 758         }
 759
 760         int Offset = -Src.getOffset();
 761
 762         FinalSize += TargetAsmInfo::getULEB128Size(Offset);
 763       } else {
 764         assert(0 && "Machine move no supported yet.");
 765       }
 766     } else if (Src.isReg() &&
 767       Src.getReg() == MachineLocation::VirtualFP) {
 768       if (Dst.isReg()) {
 769         ++FinalSize;
 770         unsigned RegNum = RI->getDwarfRegNum(Dst.getReg(), true);
 771         FinalSize += TargetAsmInfo::getULEB128Size(RegNum);
 772       } else {
 773         assert(0 && "Machine move no supported yet.");
 774       }
 775     } else {
 776       unsigned Reg = RI->getDwarfRegNum(Src.getReg(), true);
 777       int Offset = Dst.getOffset() / stackGrowth;
 778
 779       if (Offset < 0) {
 780         ++FinalSize;
 781         FinalSize += TargetAsmInfo::getULEB128Size(Reg);
 782         FinalSize += TargetAsmInfo::getSLEB128Size(Offset);
 783       } else if (Reg < 64) {
 784         ++FinalSize;
 785         FinalSize += TargetAsmInfo::getULEB128Size(Offset);
 786       } else {
 787         ++FinalSize;
 788         FinalSize += TargetAsmInfo::getULEB128Size(Reg);
 789         FinalSize += TargetAsmInfo::getULEB128Size(Offset);
 790       }
 791     }
 792   }
 793   return FinalSize;
 794 }
 795
 796 unsigned
 797 JITDwarfEmitter::GetExceptionTableSizeInBytes(MachineFunction* MF) const {
 798   unsigned FinalSize = 0;
 799
 800   // Map all labels and get rid of any dead landing pads.
 801   MMI->TidyLandingPads();
 802
 803   const std::vector<GlobalVariable *> &TypeInfos = MMI->getTypeInfos();
 804   const std::vector<unsigned> &FilterIds = MMI->getFilterIds();
 805   const std::vector<LandingPadInfo> &PadInfos = MMI->getLandingPads();
 806   if (PadInfos.empty()) return 0;
 807
 808   // Sort the landing pads in order of their type ids.  This is used to fold
 809   // duplicate actions.
 810   SmallVector<const LandingPadInfo *, 64> LandingPads;
 811   LandingPads.reserve(PadInfos.size());
 812   for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
 813     LandingPads.push_back(&PadInfos[i]);
 814   std::sort(LandingPads.begin(), LandingPads.end(), PadLT);
 815
 816   // Negative type ids index into FilterIds, positive type ids index into
 817   // TypeInfos.  The value written for a positive type id is just the type
 818   // id itself.  For a negative type id, however, the value written is the
 819   // (negative) byte offset of the corresponding FilterIds entry.  The byte
 820   // offset is usually equal to the type id, because the FilterIds entries
 821   // are written using a variable width encoding which outputs one byte per
 822   // entry as long as the value written is not too large, but can differ.
 823   // This kind of complication does not occur for positive type ids because
 824   // type infos are output using a fixed width encoding.
 825   // FilterOffsets[i] holds the byte offset corresponding to FilterIds[i].
 826   SmallVector<int, 16> FilterOffsets;
 827   FilterOffsets.reserve(FilterIds.size());
 828   int Offset = -1;
 829   for(std::vector<unsigned>::const_iterator I = FilterIds.begin(),
 830     E = FilterIds.end(); I != E; ++I) {
 831     FilterOffsets.push_back(Offset);
 832     Offset -= TargetAsmInfo::getULEB128Size(*I);
 833   }
 834
 835   // Compute the actions table and gather the first action index for each
 836   // landing pad site.
 837   SmallVector<ActionEntry, 32> Actions;
 838   SmallVector<unsigned, 64> FirstActions;
 839   FirstActions.reserve(LandingPads.size());
 840
 841   int FirstAction = 0;
 842   unsigned SizeActions = 0;
 843   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
 844     const LandingPadInfo *LP = LandingPads[i];
 845     const std::vector<int> &TypeIds = LP->TypeIds;
 846     const unsigned NumShared = i ? SharedTypeIds(LP, LandingPads[i-1]) : 0;
 847     unsigned SizeSiteActions = 0;
 848
 849     if (NumShared < TypeIds.size()) {
 850       unsigned SizeAction = 0;
 851       ActionEntry *PrevAction = 0;
 852
 853       if (NumShared) {
 854         const unsigned SizePrevIds = LandingPads[i-1]->TypeIds.size();
 855         assert(Actions.size());
 856         PrevAction = &Actions.back();
 857         SizeAction = TargetAsmInfo::getSLEB128Size(PrevAction->NextAction) +
 858           TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
 859         for (unsigned j = NumShared; j != SizePrevIds; ++j) {
 860           SizeAction -= TargetAsmInfo::getSLEB128Size(PrevAction->ValueForTypeID);
 861           SizeAction += -PrevAction->NextAction;
 862           PrevAction = PrevAction->Previous;
 863         }
 864       }
 865
 866       // Compute the actions.
 867       for (unsigned I = NumShared, M = TypeIds.size(); I != M; ++I) {
 868         int TypeID = TypeIds[I];
 869         assert(-1-TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
 870         int ValueForTypeID = TypeID < 0 ? FilterOffsets[-1 - TypeID] : TypeID;
 871         unsigned SizeTypeID = TargetAsmInfo::getSLEB128Size(ValueForTypeID);
 872
 873         int NextAction = SizeAction ? -(SizeAction + SizeTypeID) : 0;
 874         SizeAction = SizeTypeID + TargetAsmInfo::getSLEB128Size(NextAction);
 875         SizeSiteActions += SizeAction;
 876
 877         ActionEntry Action = {ValueForTypeID, NextAction, PrevAction};
 878         Actions.push_back(Action);
 879
 880         PrevAction = &Actions.back();
 881       }
 882
 883       // Record the first action of the landing pad site.
 884       FirstAction = SizeActions + SizeSiteActions - SizeAction + 1;
 885     } // else identical - re-use previous FirstAction
 886
 887     FirstActions.push_back(FirstAction);
 888
 889     // Compute this sites contribution to size.
 890     SizeActions += SizeSiteActions;
 891   }
 892
 893   // Compute the call-site table.  Entries must be ordered by address.
 894   SmallVector<CallSiteEntry, 64> CallSites;
 895
 896   RangeMapType PadMap;
 897   for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
 898     const LandingPadInfo *LandingPad = LandingPads[i];
 899     for (unsigned j=0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
 900       unsigned BeginLabel = LandingPad->BeginLabels[j];
 901       assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
 902       PadRange P = { i, j };
 903       PadMap[BeginLabel] = P;
 904     }
 905   }
 906
 907   bool MayThrow = false;
 908   unsigned LastLabel = 0;
 909   for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
 910         I != E; ++I) {
 911     for (MachineBasicBlock::const_iterator MI = I->begin(), E = I->end();
 912           MI != E; ++MI) {
 913       if (!MI->isLabel()) {
 914         MayThrow |= MI->getDesc().isCall();
 915         continue;
 916       }
 917
 918       unsigned BeginLabel = MI->getOperand(0).getImm();
 919       assert(BeginLabel && "Invalid label!");
 920
 921       if (BeginLabel == LastLabel)
 922         MayThrow = false;
 923
 924       RangeMapType::iterator L = PadMap.find(BeginLabel);
 925
 926       if (L == PadMap.end())
 927         continue;
 928
 929       PadRange P = L->second;
 930       const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
 931
 932       assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
 933               "Inconsistent landing pad map!");
 934
 935       // If some instruction between the previous try-range and this one may
 936       // throw, create a call-site entry with no landing pad for the region
 937       // between the try-ranges.
 938       if (MayThrow) {
 939         CallSiteEntry Site = {LastLabel, BeginLabel, 0, 0};
 940         CallSites.push_back(Site);
 941       }
 942
 943       LastLabel = LandingPad->EndLabels[P.RangeIndex];
 944       CallSiteEntry Site = {BeginLabel, LastLabel,
 945         LandingPad->LandingPadLabel, FirstActions[P.PadIndex]};
 946
 947       assert(Site.BeginLabel && Site.EndLabel && Site.PadLabel &&
 948               "Invalid landing pad!");
 949
 950       // Try to merge with the previous call-site.
 951       if (CallSites.size()) {
 952         CallSiteEntry &Prev = CallSites.back();
 953         if (Site.PadLabel == Prev.PadLabel && Site.Action == Prev.Action) {
 954           // Extend the range of the previous entry.
 955           Prev.EndLabel = Site.EndLabel;
 956           continue;
 957         }
 958       }
 959
 960       // Otherwise, create a new call-site.
 961       CallSites.push_back(Site);
 962     }
 963   }
 964   // If some instruction between the previous try-range and the end of the
 965   // function may throw, create a call-site entry with no landing pad for the
 966   // region following the try-range.
 967   if (MayThrow) {
 968     CallSiteEntry Site = {LastLabel, 0, 0, 0};
 969     CallSites.push_back(Site);
 970   }
 971
 972   // Final tallies.
 973   unsigned SizeSites = CallSites.size() * (sizeof(int32_t) + // Site start.
 974                                             sizeof(int32_t) + // Site length.
 975                                             sizeof(int32_t)); // Landing pad.
 976   for (unsigned i = 0, e = CallSites.size(); i < e; ++i)
 977     SizeSites += TargetAsmInfo::getULEB128Size(CallSites[i].Action);
 978
 979   unsigned SizeTypes = TypeInfos.size() * TD->getPointerSize();
 980
 981   unsigned TypeOffset = sizeof(int8_t) + // Call site format
 982                         // Call-site table length
 983                         TargetAsmInfo::getULEB128Size(SizeSites) +
 984                         SizeSites + SizeActions + SizeTypes;
 985
 986   unsigned TotalSize = sizeof(int8_t) + // LPStart format
 987                        sizeof(int8_t) + // TType format
 988                        TargetAsmInfo::getULEB128Size(TypeOffset) + // TType base offset
 989                        TypeOffset;
 990
 991   unsigned SizeAlign = (4 - TotalSize) & 3;
 992
 993   // Begin the exception table.
 994   FinalSize = RoundUpToAlign(FinalSize, 4);
 995   for (unsigned i = 0; i != SizeAlign; ++i) {
 996     ++FinalSize;
 997   }
 998
 999   unsigned PointerSize = TD->getPointerSize();
1000
1001   // Emit the header.
1002   ++FinalSize;
1003   // Asm->EOL("LPStart format (DW_EH_PE_omit)");
1004   ++FinalSize;
1005   // Asm->EOL("TType format (DW_EH_PE_absptr)");
1006   ++FinalSize;
1007   // Asm->EOL("TType base offset");
1008   ++FinalSize;
1009   // Asm->EOL("Call site format (DW_EH_PE_udata4)");
1010   ++FinalSize;
1011   // Asm->EOL("Call-site table length");
1012
1013   // Emit the landing pad site information.
1014   for (unsigned i = 0; i < CallSites.size(); ++i) {
1015     CallSiteEntry &S = CallSites[i];
1016
1017     // Asm->EOL("Region start");
1018     FinalSize += PointerSize;
1019
1020     //Asm->EOL("Region length");
1021     FinalSize += PointerSize;
1022
1023     // Asm->EOL("Landing pad");
1024     FinalSize += PointerSize;
1025
1026     FinalSize += TargetAsmInfo::getULEB128Size(S.Action);
1027     // Asm->EOL("Action");
1028   }
1029
1030   // Emit the actions.
1031   for (unsigned I = 0, N = Actions.size(); I != N; ++I) {
1032     ActionEntry &Action = Actions[I];
1033
1034     //Asm->EOL("TypeInfo index");
1035     FinalSize += TargetAsmInfo::getSLEB128Size(Action.ValueForTypeID);
1036     //Asm->EOL("Next action");
1037     FinalSize += TargetAsmInfo::getSLEB128Size(Action.NextAction);
1038   }
1039
1040   // Emit the type ids.
1041   for (unsigned M = TypeInfos.size(); M; --M) {
1042     // Asm->EOL("TypeInfo");
1043     FinalSize += PointerSize;
1044   }
1045
1046   // Emit the filter typeids.
1047   for (unsigned j = 0, M = FilterIds.size(); j < M; ++j) {
1048     unsigned TypeID = FilterIds[j];
1049     FinalSize += TargetAsmInfo::getULEB128Size(TypeID);
1050     //Asm->EOL("Filter TypeInfo index");
1051   }
1052
1053   FinalSize = RoundUpToAlign(FinalSize, 4);
1054
1055   return FinalSize;
1056 }