lib/CodeGen/MachineModuleInfo.cpp

   1 //===-- llvm/CodeGen/MachineModuleInfo.cpp ----------------------*- C++ -*-===//
   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 #include "llvm/CodeGen/MachineModuleInfo.h"
  11
  12 #include "llvm/Constants.h"
  13 #include "llvm/Analysis/ValueTracking.h"
  14 #include "llvm/CodeGen/MachineFunctionPass.h"
  15 #include "llvm/CodeGen/MachineFunction.h"
  16 #include "llvm/CodeGen/Passes.h"
  17 #include "llvm/Target/TargetInstrInfo.h"
  18 #include "llvm/Target/TargetMachine.h"
  19 #include "llvm/Target/TargetOptions.h"
  20 #include "llvm/DerivedTypes.h"
  21 #include "llvm/GlobalVariable.h"
  22 #include "llvm/Intrinsics.h"
  23 #include "llvm/Instructions.h"
  24 #include "llvm/Module.h"
  25 #include "llvm/Support/Dwarf.h"
  26 #include "llvm/Support/ErrorHandling.h"
  27 #include "llvm/Support/Streams.h"
  28 using namespace llvm;
  29 using namespace llvm::dwarf;
  30
  31 // Handle the Pass registration stuff necessary to use TargetData's.
  32 static RegisterPass<MachineModuleInfo>
  33 X("machinemoduleinfo", "Module Information");
  34 char MachineModuleInfo::ID = 0;
  35
  36 //===----------------------------------------------------------------------===//
  37
  38 MachineModuleInfo::MachineModuleInfo()
  39 : ImmutablePass(&ID)
  40 , LabelIDList()
  41 , FrameMoves()
  42 , LandingPads()
  43 , Personalities()
  44 , CallsEHReturn(0)
  45 , CallsUnwindInit(0)
  46 , DbgInfoAvailable(false)
  47 {
  48   // Always emit "no personality" info
  49   Personalities.push_back(NULL);
  50 }
  51 MachineModuleInfo::~MachineModuleInfo() {
  52
  53 }
  54
  55 /// doInitialization - Initialize the state for a new module.
  56 ///
  57 bool MachineModuleInfo::doInitialization() {
  58   return false;
  59 }
  60
  61 /// doFinalization - Tear down the state after completion of a module.
  62 ///
  63 bool MachineModuleInfo::doFinalization() {
  64   return false;
  65 }
  66
  67 /// BeginFunction - Begin gathering function meta information.
  68 ///
  69 void MachineModuleInfo::BeginFunction(MachineFunction *MF) {
  70   // Coming soon.
  71 }
  72
  73 /// EndFunction - Discard function meta information.
  74 ///
  75 void MachineModuleInfo::EndFunction() {
  76   // Clean up frame info.
  77   FrameMoves.clear();
  78
  79   // Clean up exception info.
  80   LandingPads.clear();
  81   TypeInfos.clear();
  82   FilterIds.clear();
  83   FilterEnds.clear();
  84   CallsEHReturn = 0;
  85   CallsUnwindInit = 0;
  86 }
  87
  88 /// AnalyzeModule - Scan the module for global debug information.
  89 ///
  90 void MachineModuleInfo::AnalyzeModule(Module &M) {
  91   // Insert functions in the llvm.used array (but not llvm.compiler.used) into
  92   // UsedFunctions.
  93   GlobalVariable *GV = M.getGlobalVariable("llvm.used");
  94   if (!GV || !GV->hasInitializer()) return;
  95
  96   // Should be an array of 'i8*'.
  97   ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
  98   if (InitList == 0) return;
  99
 100   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
 101     if (Function *F =
 102           dyn_cast<Function>(InitList->getOperand(i)->stripPointerCasts()))
 103       UsedFunctions.insert(F);
 104 }
 105
 106 //===-EH-------------------------------------------------------------------===//
 107
 108 /// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
 109 /// specified MachineBasicBlock.
 110 LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
 111     (MachineBasicBlock *LandingPad) {
 112   unsigned N = LandingPads.size();
 113   for (unsigned i = 0; i < N; ++i) {
 114     LandingPadInfo &LP = LandingPads[i];
 115     if (LP.LandingPadBlock == LandingPad)
 116       return LP;
 117   }
 118
 119   LandingPads.push_back(LandingPadInfo(LandingPad));
 120   return LandingPads[N];
 121 }
 122
 123 /// addInvoke - Provide the begin and end labels of an invoke style call and
 124 /// associate it with a try landing pad block.
 125 void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
 126                                   unsigned BeginLabel, unsigned EndLabel) {
 127   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 128   LP.BeginLabels.push_back(BeginLabel);
 129   LP.EndLabels.push_back(EndLabel);
 130 }
 131
 132 /// addLandingPad - Provide the label of a try LandingPad block.
 133 ///
 134 unsigned MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
 135   unsigned LandingPadLabel = NextLabelID();
 136   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 137   LP.LandingPadLabel = LandingPadLabel;
 138   return LandingPadLabel;
 139 }
 140
 141 /// addPersonality - Provide the personality function for the exception
 142 /// information.
 143 void MachineModuleInfo::addPersonality(MachineBasicBlock *LandingPad,
 144                                        Function *Personality) {
 145   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 146   LP.Personality = Personality;
 147
 148   for (unsigned i = 0; i < Personalities.size(); ++i)
 149     if (Personalities[i] == Personality)
 150       return;
 151
 152   Personalities.push_back(Personality);
 153 }
 154
 155 /// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
 156 ///
 157 void MachineModuleInfo::addCatchTypeInfo(MachineBasicBlock *LandingPad,
 158                                         std::vector<GlobalVariable *> &TyInfo) {
 159   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 160   for (unsigned N = TyInfo.size(); N; --N)
 161     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
 162 }
 163
 164 /// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
 165 ///
 166 void MachineModuleInfo::addFilterTypeInfo(MachineBasicBlock *LandingPad,
 167                                         std::vector<GlobalVariable *> &TyInfo) {
 168   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 169   std::vector<unsigned> IdsInFilter(TyInfo.size());
 170   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
 171     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
 172   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 173 }
 174
 175 /// addCleanup - Add a cleanup action for a landing pad.
 176 ///
 177 void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
 178   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 179   LP.TypeIds.push_back(0);
 180 }
 181
 182 /// TidyLandingPads - Remap landing pad labels and remove any deleted landing
 183 /// pads.
 184 void MachineModuleInfo::TidyLandingPads() {
 185   for (unsigned i = 0; i != LandingPads.size(); ) {
 186     LandingPadInfo &LandingPad = LandingPads[i];
 187     LandingPad.LandingPadLabel = MappedLabel(LandingPad.LandingPadLabel);
 188
 189     // Special case: we *should* emit LPs with null LP MBB. This indicates
 190     // "nounwind" case.
 191     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
 192       LandingPads.erase(LandingPads.begin() + i);
 193       continue;
 194     }
 195
 196     for (unsigned j=0; j != LandingPads[i].BeginLabels.size(); ) {
 197       unsigned BeginLabel = MappedLabel(LandingPad.BeginLabels[j]);
 198       unsigned EndLabel = MappedLabel(LandingPad.EndLabels[j]);
 199
 200       if (!BeginLabel || !EndLabel) {
 201         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
 202         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
 203         continue;
 204       }
 205
 206       LandingPad.BeginLabels[j] = BeginLabel;
 207       LandingPad.EndLabels[j] = EndLabel;
 208       ++j;
 209     }
 210
 211     // Remove landing pads with no try-ranges.
 212     if (LandingPads[i].BeginLabels.empty()) {
 213       LandingPads.erase(LandingPads.begin() + i);
 214       continue;
 215     }
 216
 217     // If there is no landing pad, ensure that the list of typeids is empty.
 218     // If the only typeid is a cleanup, this is the same as having no typeids.
 219     if (!LandingPad.LandingPadBlock ||
 220         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
 221       LandingPad.TypeIds.clear();
 222
 223     ++i;
 224   }
 225 }
 226
 227 /// getTypeIDFor - Return the type id for the specified typeinfo.  This is
 228 /// function wide.
 229 unsigned MachineModuleInfo::getTypeIDFor(GlobalVariable *TI) {
 230   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
 231     if (TypeInfos[i] == TI) return i + 1;
 232
 233   TypeInfos.push_back(TI);
 234   return TypeInfos.size();
 235 }
 236
 237 /// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
 238 /// function wide.
 239 int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
 240   // If the new filter coincides with the tail of an existing filter, then
 241   // re-use the existing filter.  Folding filters more than this requires
 242   // re-ordering filters and/or their elements - probably not worth it.
 243   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
 244        E = FilterEnds.end(); I != E; ++I) {
 245     unsigned i = *I, j = TyIds.size();
 246
 247     while (i && j)
 248       if (FilterIds[--i] != TyIds[--j])
 249         goto try_next;
 250
 251     if (!j)
 252       // The new filter coincides with range [i, end) of the existing filter.
 253       return -(1 + i);
 254
 255 try_next:;
 256   }
 257
 258   // Add the new filter.
 259   int FilterID = -(1 + FilterIds.size());
 260   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
 261   for (unsigned I = 0, N = TyIds.size(); I != N; ++I)
 262     FilterIds.push_back(TyIds[I]);
 263   FilterEnds.push_back(FilterIds.size());
 264   FilterIds.push_back(0); // terminator
 265   return FilterID;
 266 }
 267
 268 /// getPersonality - Return the personality function for the current function.
 269 Function *MachineModuleInfo::getPersonality() const {
 270   // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
 271   // function
 272   return !LandingPads.empty() ? LandingPads[0].Personality : NULL;
 273 }
 274
 275 /// getPersonalityIndex - Return unique index for current personality
 276 /// function. NULL personality function should always get zero index.
 277 unsigned MachineModuleInfo::getPersonalityIndex() const {
 278   const Function* Personality = NULL;
 279
 280   // Scan landing pads. If there is at least one non-NULL personality - use it.
 281   for (unsigned i = 0; i != LandingPads.size(); ++i)
 282     if (LandingPads[i].Personality) {
 283       Personality = LandingPads[i].Personality;
 284       break;
 285     }
 286
 287   for (unsigned i = 0; i < Personalities.size(); ++i) {
 288     if (Personalities[i] == Personality)
 289       return i;
 290   }
 291
 292   // This should never happen
 293   llvm_unreachable("Personality function should be set!");
 294   return 0;
 295 }
 296
 297 //===----------------------------------------------------------------------===//
 298 /// DebugLabelFolding pass - This pass prunes out redundant labels.  This allows
 299 /// a info consumer to determine if the range of two labels is empty, by seeing
 300 /// if the labels map to the same reduced label.
 301
 302 namespace llvm {
 303
 304 struct DebugLabelFolder : public MachineFunctionPass {
 305   static char ID;
 306   DebugLabelFolder() : MachineFunctionPass(&ID) {}
 307
 308   virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 309     AU.setPreservesCFG();
 310     AU.addPreservedID(MachineLoopInfoID);
 311     AU.addPreservedID(MachineDominatorsID);
 312     MachineFunctionPass::getAnalysisUsage(AU);
 313   }
 314
 315   virtual bool runOnMachineFunction(MachineFunction &MF);
 316   virtual const char *getPassName() const { return "Label Folder"; }
 317 };
 318
 319 char DebugLabelFolder::ID = 0;
 320
 321 bool DebugLabelFolder::runOnMachineFunction(MachineFunction &MF) {
 322   // Get machine module info.
 323   MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
 324   if (!MMI) return false;
 325
 326   // Track if change is made.
 327   bool MadeChange = false;
 328   // No prior label to begin.
 329   unsigned PriorLabel = 0;
 330
 331   // Iterate through basic blocks.
 332   for (MachineFunction::iterator BB = MF.begin(), E = MF.end();
 333        BB != E; ++BB) {
 334     // Iterate through instructions.
 335     for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
 336       // Is it a label.
 337       if (I->isDebugLabel() && !MMI->isDbgLabelUsed(I->getOperand(0).getImm())){
 338         // The label ID # is always operand #0, an immediate.
 339         unsigned NextLabel = I->getOperand(0).getImm();
 340
 341         // If there was an immediate prior label.
 342         if (PriorLabel) {
 343           // Remap the current label to prior label.
 344           MMI->RemapLabel(NextLabel, PriorLabel);
 345           // Delete the current label.
 346           I = BB->erase(I);
 347           // Indicate a change has been made.
 348           MadeChange = true;
 349           continue;
 350         } else {
 351           // Start a new round.
 352           PriorLabel = NextLabel;
 353         }
 354        } else {
 355         // No consecutive labels.
 356         PriorLabel = 0;
 357       }
 358
 359       ++I;
 360     }
 361   }
 362
 363   return MadeChange;
 364 }
 365
 366 FunctionPass *createDebugLabelFoldingPass() { return new DebugLabelFolder(); }
 367
 368 }
 369