C++ DILocation::getInlinedAt方法代码示例

void LineNumberAnnotatedWriter::emitInstructionAnnot(
      const Instruction *I, formatted_raw_ostream &Out)
{
    DILocation *NewInstrLoc = I->getDebugLoc();
    if (!NewInstrLoc) {
        auto Loc = DebugLoc.find(I);
        if (Loc != DebugLoc.end())
            NewInstrLoc = Loc->second;
    }
    if (!NewInstrLoc || NewInstrLoc == InstrLoc)
        return;
    InstrLoc = NewInstrLoc;
    std::vector<DILineInfo> DIvec;
    do {
        DIvec.emplace_back();
        DILineInfo &DI = DIvec.back();
        DIScope *scope = NewInstrLoc->getScope();
        if (scope)
            DI.FunctionName = scope->getName();
        DI.FileName = NewInstrLoc->getFilename();
        DI.Line = NewInstrLoc->getLine();
        NewInstrLoc = NewInstrLoc->getInlinedAt();
    } while (NewInstrLoc);
    LinePrinter.emit_lineinfo(Out, DIvec);
}

const DILocation *DILocation::getMergedLocation(const DILocation *LocA,
                                                const DILocation *LocB) {
  if (!LocA || !LocB)
    return nullptr;

  if (LocA == LocB)
    return LocA;

  SmallPtrSet<DILocation *, 5> InlinedLocationsA;
  for (DILocation *L = LocA->getInlinedAt(); L; L = L->getInlinedAt())
    InlinedLocationsA.insert(L);
  SmallSet<std::pair<DIScope *, DILocation *>, 5> Locations;
  DIScope *S = LocA->getScope();
  DILocation *L = LocA->getInlinedAt();
  while (S) {
    Locations.insert(std::make_pair(S, L));
    S = S->getScope().resolve();
    if (!S && L) {
      S = L->getScope();
      L = L->getInlinedAt();
    }
  }
  const DILocation *Result = LocB;
  S = LocB->getScope();
  L = LocB->getInlinedAt();
  while (S) {
    if (Locations.count(std::make_pair(S, L)))
      break;
    S = S->getScope().resolve();
    if (!S && L) {
      S = L->getScope();
      L = L->getInlinedAt();
    }
  }

  // If the two locations are irreconsilable, just pick one. This is misleading,
  // but on the other hand, it's a "line 0" location.
  if (!S || !isa<DILocalScope>(S))
    S = LocA->getScope();
  return DILocation::get(Result->getContext(), 0, 0, S, L);
}

const DILocation *DILocation::getMergedLocation(const DILocation *LocA,
                                                const DILocation *LocB,
                                                bool GenerateLocation) {
  if (!LocA || !LocB)
    return nullptr;

  if (LocA == LocB || !LocA->canDiscriminate(*LocB))
    return LocA;

  if (!GenerateLocation)
    return nullptr;

  SmallPtrSet<DILocation *, 5> InlinedLocationsA;
  for (DILocation *L = LocA->getInlinedAt(); L; L = L->getInlinedAt())
    InlinedLocationsA.insert(L);
  const DILocation *Result = LocB;
  for (DILocation *L = LocB->getInlinedAt(); L; L = L->getInlinedAt()) {
    Result = L;
    if (InlinedLocationsA.count(L))
      break;
  }
  return DILocation::get(Result->getContext(), 0, 0, Result->getScope(),
                         Result->getInlinedAt());
}

//.........这里部分代码省略.........
/// traverses the CFG and examines instruction at basic block boundaries.
/// If the last instruction I1 of a block B1 is at the same file and line
/// location as instruction I2 of successor B2, then it creates a new
/// lexical block for I2 and all the instruction in B2 that share the same
/// file and line location as I2. This new lexical block will have a
/// different discriminator number than I1.
bool AddDiscriminators::runOnFunction(Function &F) {
  // If the function has debug information, but the user has disabled
  // discriminators, do nothing.
  // Simlarly, if the function has no debug info, do nothing.
  // Finally, if this module is built with dwarf versions earlier than 4,
  // do nothing (discriminator support is a DWARF 4 feature).
  if (NoDiscriminators || !hasDebugInfo(F) ||
      F.getParent()->getDwarfVersion() < 4)
    return false;

  bool Changed = false;
  Module *M = F.getParent();
  LLVMContext &Ctx = M->getContext();
  DIBuilder Builder(*M, /*AllowUnresolved*/ false);

  typedef std::pair<StringRef, unsigned> Location;
  typedef DenseMap<const BasicBlock *, Metadata *> BBScopeMap;
  typedef DenseMap<Location, BBScopeMap> LocationBBMap;
  typedef DenseMap<Location, unsigned> LocationDiscriminatorMap;

  LocationBBMap LBM;
  LocationDiscriminatorMap LDM;

  // Traverse all instructions in the function. If the source line location
  // of the instruction appears in other basic block, assign a new
  // discriminator for this instruction.
  for (BasicBlock &B : F) {
    for (auto &I : B.getInstList()) {
      if (isa<DbgInfoIntrinsic>(&I))
        continue;
      const DILocation *DIL = I.getDebugLoc();
      if (!DIL)
        continue;
      Location L = std::make_pair(DIL->getFilename(), DIL->getLine());
      auto &BBMap = LBM[L];
      auto R = BBMap.insert(std::make_pair(&B, (Metadata *)nullptr));
      if (BBMap.size() == 1)
        continue;
      bool InsertSuccess = R.second;
      Metadata *&NewScope = R.first->second;
      // If we could insert a different block in the same location, a
      // discriminator is needed to distinguish both instructions.
      if (InsertSuccess) {
        auto *Scope = DIL->getScope();
        auto *File =
            Builder.createFile(DIL->getFilename(), Scope->getDirectory());
        NewScope = Builder.createLexicalBlockFile(Scope, File, ++LDM[L]);
      }
      I.setDebugLoc(DILocation::get(Ctx, DIL->getLine(), DIL->getColumn(),
                                    NewScope, DIL->getInlinedAt()));
      DEBUG(dbgs() << DIL->getFilename() << ":" << DIL->getLine() << ":"
                   << DIL->getColumn() << ":"
                   << dyn_cast<DILexicalBlockFile>(NewScope)->getDiscriminator()
                   << I << "\n");
      Changed = true;
    }
  }

  // Traverse all instructions and assign new discriminators to call
  // instructions with the same lineno that are in the same basic block.
  // Sample base profile needs to distinguish different function calls within
  // a same source line for correct profile annotation.
  for (BasicBlock &B : F) {
    const DILocation *FirstDIL = nullptr;
    for (auto &I : B.getInstList()) {
      CallInst *Current = dyn_cast<CallInst>(&I);
      if (!Current || isa<DbgInfoIntrinsic>(&I))
        continue;

      DILocation *CurrentDIL = Current->getDebugLoc();
      if (FirstDIL) {
        if (CurrentDIL && CurrentDIL->getLine() == FirstDIL->getLine() &&
            CurrentDIL->getFilename() == FirstDIL->getFilename()) {
          auto *Scope = FirstDIL->getScope();
          auto *File = Builder.createFile(FirstDIL->getFilename(),
                                          Scope->getDirectory());
          Location L =
              std::make_pair(FirstDIL->getFilename(), FirstDIL->getLine());
          auto *NewScope =
              Builder.createLexicalBlockFile(Scope, File, ++LDM[L]);
          Current->setDebugLoc(DILocation::get(
              Ctx, CurrentDIL->getLine(), CurrentDIL->getColumn(), NewScope,
              CurrentDIL->getInlinedAt()));
          Changed = true;
        } else {
          FirstDIL = CurrentDIL;
        }
      } else {
        FirstDIL = CurrentDIL;
      }
    }
  }
  return Changed;
}

//.........这里部分代码省略.........
/// instruction in block 'if.then' that share the same file and line
/// location with the last instruction of block 'entry'.
///
/// This new lexical block will have the same location information as
/// the previous one, but with a new DWARF discriminator value.
///
/// One of the main uses of this discriminator value is in runtime
/// sample profilers. It allows the profiler to distinguish instructions
/// at location !dbg !10 that execute on different basic blocks. This is
/// important because while the predicate 'if (x < 10)' may have been
/// executed millions of times, the assignment 'x = i' may have only
/// executed a handful of times (meaning that the entry->if.then edge is
/// seldom taken).
///
/// If we did not have discriminator information, the profiler would
/// assign the same weight to both blocks 'entry' and 'if.then', which
/// in turn will make it conclude that the entry->if.then edge is very
/// hot.
///
/// To decide where to create new discriminator values, this function
/// traverses the CFG and examines instruction at basic block boundaries.
/// If the last instruction I1 of a block B1 is at the same file and line
/// location as instruction I2 of successor B2, then it creates a new
/// lexical block for I2 and all the instruction in B2 that share the same
/// file and line location as I2. This new lexical block will have a
/// different discriminator number than I1.
bool AddDiscriminators::runOnFunction(Function &F) {
  // If the function has debug information, but the user has disabled
  // discriminators, do nothing.
  // Simlarly, if the function has no debug info, do nothing.
  // Finally, if this module is built with dwarf versions earlier than 4,
  // do nothing (discriminator support is a DWARF 4 feature).
  if (NoDiscriminators ||
      !hasDebugInfo(F) ||
      F.getParent()->getDwarfVersion() < 4)
    return false;

  bool Changed = false;
  Module *M = F.getParent();
  LLVMContext &Ctx = M->getContext();
  DIBuilder Builder(*M, /*AllowUnresolved*/ false);

  // Traverse all the blocks looking for instructions in different
  // blocks that are at the same file:line location.
  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
    BasicBlock *B = I;
    TerminatorInst *Last = B->getTerminator();
    DILocation LastDIL = Last->getDebugLoc().get();
    if (!LastDIL)
      continue;

    for (unsigned I = 0; I < Last->getNumSuccessors(); ++I) {
      BasicBlock *Succ = Last->getSuccessor(I);
      Instruction *First = Succ->getFirstNonPHIOrDbgOrLifetime();
      DILocation FirstDIL = First->getDebugLoc().get();
      if (!FirstDIL)
        continue;

      // If the first instruction (First) of Succ is at the same file
      // location as B's last instruction (Last), add a new
      // discriminator for First's location and all the instructions
      // in Succ that share the same location with First.
      if (!FirstDIL->canDiscriminate(*LastDIL)) {
        // Create a new lexical scope and compute a new discriminator
        // number for it.
        StringRef Filename = FirstDIL->getFilename();
        auto *Scope = FirstDIL->getScope();
        auto *File = Builder.createFile(Filename, Scope->getDirectory());

        // FIXME: Calculate the discriminator here, based on local information,
        // and delete MDLocation::computeNewDiscriminator().  The current
        // solution gives different results depending on other modules in the
        // same context.  All we really need is to discriminate between
        // FirstDIL and LastDIL -- a local map would suffice.
        unsigned Discriminator = FirstDIL->computeNewDiscriminator();
        auto *NewScope =
            Builder.createLexicalBlockFile(Scope, File, Discriminator);
        auto *NewDIL =
            MDLocation::get(Ctx, FirstDIL->getLine(), FirstDIL->getColumn(),
                            NewScope, FirstDIL->getInlinedAt());
        DebugLoc newDebugLoc = NewDIL;

        // Attach this new debug location to First and every
        // instruction following First that shares the same location.
        for (BasicBlock::iterator I1(*First), E1 = Succ->end(); I1 != E1;
             ++I1) {
          if (I1->getDebugLoc().get() != FirstDIL)
            break;
          I1->setDebugLoc(newDebugLoc);
          DEBUG(dbgs() << NewDIL->getFilename() << ":" << NewDIL->getLine()
                       << ":" << NewDIL->getColumn() << ":"
                       << NewDIL->getDiscriminator() << *I1 << "\n");
        }
        DEBUG(dbgs() << "\n");
        Changed = true;
      }
    }
  }
  return Changed;
}