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 using namespace llvm;
  28 using namespace llvm::dwarf;
  29
  30 // Handle the Pass registration stuff necessary to use TargetData's.
  31 static RegisterPass<MachineModuleInfo>
  32 X("machinemoduleinfo", "Module Information");
  33 char MachineModuleInfo::ID = 0;
  34
  35 //===----------------------------------------------------------------------===//
  36
  37 MachineModuleInfo::MachineModuleInfo()
  38 : ImmutablePass(&ID)
  39 , LabelIDList()
  40 , FrameMoves()
  41 , LandingPads()
  42 , Personalities()
  43 , CallsEHReturn(0)
  44 , CallsUnwindInit(0)
  45 , DbgInfoAvailable(false)
  46 {
  47   // Always emit some info, by default "no personality" info.
  48   Personalities.push_back(NULL);
  49 }
  50 MachineModuleInfo::~MachineModuleInfo() {
  51
  52 }
  53
  54 /// doInitialization - Initialize the state for a new module.
  55 ///
  56 bool MachineModuleInfo::doInitialization() {
  57   return false;
  58 }
  59
  60 /// doFinalization - Tear down the state after completion of a module.
  61 ///
  62 bool MachineModuleInfo::doFinalization() {
  63   return false;
  64 }
  65
  66 /// BeginFunction - Begin gathering function meta information.
  67 ///
  68 void MachineModuleInfo::BeginFunction(MachineFunction *MF) {
  69   // Coming soon.
  70 }
  71
  72 /// EndFunction - Discard function meta information.
  73 ///
  74 void MachineModuleInfo::EndFunction() {
  75   // Clean up frame info.
  76   FrameMoves.clear();
  77
  78   // Clean up exception info.
  79   LandingPads.clear();
  80   TypeInfos.clear();
  81   FilterIds.clear();
  82   FilterEnds.clear();
  83   CallsEHReturn = 0;
  84   CallsUnwindInit = 0;
  85 }
  86
  87 /// AnalyzeModule - Scan the module for global debug information.
  88 ///
  89 void MachineModuleInfo::AnalyzeModule(Module &M) {
  90   // Insert functions in the llvm.used array (but not llvm.compiler.used) into
  91   // UsedFunctions.
  92   GlobalVariable *GV = M.getGlobalVariable("llvm.used");
  93   if (!GV || !GV->hasInitializer()) return;
  94
  95   // Should be an array of 'i8*'.
  96   ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
  97   if (InitList == 0) return;
  98
  99   for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i)
 100     if (Function *F =
 101           dyn_cast<Function>(InitList->getOperand(i)->stripPointerCasts()))
 102       UsedFunctions.insert(F);
 103 }
 104
 105 //===-EH-------------------------------------------------------------------===//
 106
 107 /// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
 108 /// specified MachineBasicBlock.
 109 LandingPadInfo &MachineModuleInfo::getOrCreateLandingPadInfo
 110     (MachineBasicBlock *LandingPad) {
 111   unsigned N = LandingPads.size();
 112   for (unsigned i = 0; i < N; ++i) {
 113     LandingPadInfo &LP = LandingPads[i];
 114     if (LP.LandingPadBlock == LandingPad)
 115       return LP;
 116   }
 117
 118   LandingPads.push_back(LandingPadInfo(LandingPad));
 119   return LandingPads[N];
 120 }
 121
 122 /// addInvoke - Provide the begin and end labels of an invoke style call and
 123 /// associate it with a try landing pad block.
 124 void MachineModuleInfo::addInvoke(MachineBasicBlock *LandingPad,
 125                                   unsigned BeginLabel, unsigned EndLabel) {
 126   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 127   LP.BeginLabels.push_back(BeginLabel);
 128   LP.EndLabels.push_back(EndLabel);
 129 }
 130
 131 /// addLandingPad - Provide the label of a try LandingPad block.
 132 ///
 133 unsigned MachineModuleInfo::addLandingPad(MachineBasicBlock *LandingPad) {
 134   unsigned LandingPadLabel = NextLabelID();
 135   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 136   LP.LandingPadLabel = LandingPadLabel;
 137   return LandingPadLabel;
 138 }
 139
 140 /// addPersonality - Provide the personality function for the exception
 141 /// information.
 142 void MachineModuleInfo::addPersonality(MachineBasicBlock *LandingPad,
 143                                        Function *Personality) {
 144   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 145   LP.Personality = Personality;
 146
 147   for (unsigned i = 0; i < Personalities.size(); ++i)
 148     if (Personalities[i] == Personality)
 149       return;
 150
 151   // If this is the first personality we're adding go
 152   // ahead and add it at the beginning.
 153   if (Personalities[0] == NULL)
 154     Personalities[0] = Personality;
 155   else
 156     Personalities.push_back(Personality);
 157 }
 158
 159 /// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
 160 ///
 161 void MachineModuleInfo::addCatchTypeInfo(MachineBasicBlock *LandingPad,
 162                                         std::vector<GlobalVariable *> &TyInfo) {
 163   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 164   for (unsigned N = TyInfo.size(); N; --N)
 165     LP.TypeIds.push_back(getTypeIDFor(TyInfo[N - 1]));
 166 }
 167
 168 /// addFilterTypeInfo - Provide the filter typeinfo for a landing pad.
 169 ///
 170 void MachineModuleInfo::addFilterTypeInfo(MachineBasicBlock *LandingPad,
 171                                         std::vector<GlobalVariable *> &TyInfo) {
 172   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 173   std::vector<unsigned> IdsInFilter(TyInfo.size());
 174   for (unsigned I = 0, E = TyInfo.size(); I != E; ++I)
 175     IdsInFilter[I] = getTypeIDFor(TyInfo[I]);
 176   LP.TypeIds.push_back(getFilterIDFor(IdsInFilter));
 177 }
 178
 179 /// addCleanup - Add a cleanup action for a landing pad.
 180 ///
 181 void MachineModuleInfo::addCleanup(MachineBasicBlock *LandingPad) {
 182   LandingPadInfo &LP = getOrCreateLandingPadInfo(LandingPad);
 183   LP.TypeIds.push_back(0);
 184 }
 185
 186 /// TidyLandingPads - Remap landing pad labels and remove any deleted landing
 187 /// pads.
 188 void MachineModuleInfo::TidyLandingPads() {
 189   for (unsigned i = 0; i != LandingPads.size(); ) {
 190     LandingPadInfo &LandingPad = LandingPads[i];
 191     LandingPad.LandingPadLabel = MappedLabel(LandingPad.LandingPadLabel);
 192
 193     // Special case: we *should* emit LPs with null LP MBB. This indicates
 194     // "nounwind" case.
 195     if (!LandingPad.LandingPadLabel && LandingPad.LandingPadBlock) {
 196       LandingPads.erase(LandingPads.begin() + i);
 197       continue;
 198     }
 199
 200     for (unsigned j=0; j != LandingPads[i].BeginLabels.size(); ) {
 201       unsigned BeginLabel = MappedLabel(LandingPad.BeginLabels[j]);
 202       unsigned EndLabel = MappedLabel(LandingPad.EndLabels[j]);
 203
 204       if (!BeginLabel || !EndLabel) {
 205         LandingPad.BeginLabels.erase(LandingPad.BeginLabels.begin() + j);
 206         LandingPad.EndLabels.erase(LandingPad.EndLabels.begin() + j);
 207         continue;
 208       }
 209
 210       LandingPad.BeginLabels[j] = BeginLabel;
 211       LandingPad.EndLabels[j] = EndLabel;
 212       ++j;
 213     }
 214
 215     // Remove landing pads with no try-ranges.
 216     if (LandingPads[i].BeginLabels.empty()) {
 217       LandingPads.erase(LandingPads.begin() + i);
 218       continue;
 219     }
 220
 221     // If there is no landing pad, ensure that the list of typeids is empty.
 222     // If the only typeid is a cleanup, this is the same as having no typeids.
 223     if (!LandingPad.LandingPadBlock ||
 224         (LandingPad.TypeIds.size() == 1 && !LandingPad.TypeIds[0]))
 225       LandingPad.TypeIds.clear();
 226
 227     ++i;
 228   }
 229 }
 230
 231 /// getTypeIDFor - Return the type id for the specified typeinfo.  This is
 232 /// function wide.
 233 unsigned MachineModuleInfo::getTypeIDFor(GlobalVariable *TI) {
 234   for (unsigned i = 0, N = TypeInfos.size(); i != N; ++i)
 235     if (TypeInfos[i] == TI) return i + 1;
 236
 237   TypeInfos.push_back(TI);
 238   return TypeInfos.size();
 239 }
 240
 241 /// getFilterIDFor - Return the filter id for the specified typeinfos.  This is
 242 /// function wide.
 243 int MachineModuleInfo::getFilterIDFor(std::vector<unsigned> &TyIds) {
 244   // If the new filter coincides with the tail of an existing filter, then
 245   // re-use the existing filter.  Folding filters more than this requires
 246   // re-ordering filters and/or their elements - probably not worth it.
 247   for (std::vector<unsigned>::iterator I = FilterEnds.begin(),
 248        E = FilterEnds.end(); I != E; ++I) {
 249     unsigned i = *I, j = TyIds.size();
 250
 251     while (i && j)
 252       if (FilterIds[--i] != TyIds[--j])
 253         goto try_next;
 254
 255     if (!j)
 256       // The new filter coincides with range [i, end) of the existing filter.
 257       return -(1 + i);
 258
 259 try_next:;
 260   }
 261
 262   // Add the new filter.
 263   int FilterID = -(1 + FilterIds.size());
 264   FilterIds.reserve(FilterIds.size() + TyIds.size() + 1);
 265   for (unsigned I = 0, N = TyIds.size(); I != N; ++I)
 266     FilterIds.push_back(TyIds[I]);
 267   FilterEnds.push_back(FilterIds.size());
 268   FilterIds.push_back(0); // terminator
 269   return FilterID;
 270 }
 271
 272 /// getPersonality - Return the personality function for the current function.
 273 Function *MachineModuleInfo::getPersonality() const {
 274   // FIXME: Until PR1414 will be fixed, we're using 1 personality function per
 275   // function
 276   return !LandingPads.empty() ? LandingPads[0].Personality : NULL;
 277 }
 278
 279 /// getPersonalityIndex - Return unique index for current personality
 280 /// function. NULL/first personality function should always get zero index.
 281 unsigned MachineModuleInfo::getPersonalityIndex() const {
 282   const Function* Personality = NULL;
 283
 284   // Scan landing pads. If there is at least one non-NULL personality - use it.
 285   for (unsigned i = 0; i != LandingPads.size(); ++i)
 286     if (LandingPads[i].Personality) {
 287       Personality = LandingPads[i].Personality;
 288       break;
 289     }
 290
 291   for (unsigned i = 0; i < Personalities.size(); ++i) {
 292     if (Personalities[i] == Personality)
 293       return i;
 294   }
 295
 296   // This will happen if the current personality function is
 297   // in the zero index.
 298   return 0;
 299 }
 300
 301 //===----------------------------------------------------------------------===//
 302 /// DebugLabelFolding pass - This pass prunes out redundant labels.  This allows
 303 /// a info consumer to determine if the range of two labels is empty, by seeing
 304 /// if the labels map to the same reduced label.
 305
 306 namespace llvm {
 307
 308 struct DebugLabelFolder : public MachineFunctionPass {
 309   static char ID;
 310   DebugLabelFolder() : MachineFunctionPass(&ID) {}
 311
 312   virtual void getAnalysisUsage(AnalysisUsage &AU) const {
 313     AU.setPreservesCFG();
 314     AU.addPreservedID(MachineLoopInfoID);
 315     AU.addPreservedID(MachineDominatorsID);
 316     MachineFunctionPass::getAnalysisUsage(AU);
 317   }
 318
 319   virtual bool runOnMachineFunction(MachineFunction &MF);
 320   virtual const char *getPassName() const { return "Label Folder"; }
 321 };
 322
 323 char DebugLabelFolder::ID = 0;
 324
 325 bool DebugLabelFolder::runOnMachineFunction(MachineFunction &MF) {
 326   // Get machine module info.
 327   MachineModuleInfo *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
 328   if (!MMI) return false;
 329
 330   // Track if change is made.
 331   bool MadeChange = false;
 332   // No prior label to begin.
 333   unsigned PriorLabel = 0;
 334
 335   // Iterate through basic blocks.
 336   for (MachineFunction::iterator BB = MF.begin(), E = MF.end();
 337        BB != E; ++BB) {
 338     // Iterate through instructions.
 339     for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
 340       // Is it a label.
 341       if (I->isDebugLabel() && !MMI->isDbgLabelUsed(I->getOperand(0).getImm())){
 342         // The label ID # is always operand #0, an immediate.
 343         unsigned NextLabel = I->getOperand(0).getImm();
 344
 345         // If there was an immediate prior label.
 346         if (PriorLabel) {
 347           // Remap the current label to prior label.
 348           MMI->RemapLabel(NextLabel, PriorLabel);
 349           // Delete the current label.
 350           I = BB->erase(I);
 351           // Indicate a change has been made.
 352           MadeChange = true;
 353           continue;
 354         } else {
 355           // Start a new round.
 356           PriorLabel = NextLabel;
 357         }
 358        } else {
 359         // No consecutive labels.
 360         PriorLabel = 0;
 361       }
 362
 363       ++I;
 364     }
 365   }
 366
 367   return MadeChange;
 368 }
 369
 370 FunctionPass *createDebugLabelFoldingPass() { return new DebugLabelFolder(); }
 371
 372 }