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