Commit 9583a3f2 authored by Fangrui Song's avatar Fangrui Song
Browse files

[AsmPrinter] Delete dead takeDeletedSymbsForFunction() 

The code added in r98579 is dead now.
parent e68c1e00

llvm/include/llvm/CodeGen/MachineModuleInfo.h

+0 −7
Original line number Diff line number Diff line
@@ -233,13 +233,6 @@ public: 
  /// to emit them as well, return the whole set.

  ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(const BasicBlock *BB);



  /// If the specified function has had any references to address-taken blocks

  /// generated, but the block got deleted, return the symbol now so we can

  /// emit it.  This prevents emitting a reference to a symbol that has no

  /// definition.

  void takeDeletedSymbolsForFunction(const Function *F,

                                     std::vector<MCSymbol*> &Result);



  /// \name Exception Handling

  /// \{

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

+0 −10
Original line number Diff line number Diff line
@@ -715,16 +715,6 @@ void AsmPrinter::EmitFunctionHeader() { 
  // their wild and crazy things as required.

  EmitFunctionEntryLabel();



  // If the function had address-taken blocks that got deleted, then we have

  // references to the dangling symbols.  Emit them at the start of the function

  // so that we don't get references to undefined symbols.

  std::vector<MCSymbol*> DeadBlockSyms;

  MMI->takeDeletedSymbolsForFunction(&F, DeadBlockSyms);

  for (unsigned i = 0, e = DeadBlockSyms.size(); i != e; ++i) {

    OutStreamer->AddComment("Address taken block that was later removed");

    OutStreamer->EmitLabel(DeadBlockSyms[i]);

  }



  if (CurrentFnBegin) {

    if (MAI->useAssignmentForEHBegin()) {

      MCSymbol *CurPos = OutContext.createTempSymbol();

llvm/lib/CodeGen/MachineModuleInfo.cpp

+2 −47
Original line number Diff line number Diff line
@@ -76,25 +76,11 @@ class MMIAddrLabelMap { 
  /// we get notified if a block is deleted or RAUWd.

  std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;



  /// This is a per-function list of symbols whose corresponding BasicBlock got

  /// deleted.  These symbols need to be emitted at some point in the file, so

  /// AsmPrinter emits them after the function body.

  DenseMap<AssertingVH<Function>, std::vector<MCSymbol*>>

    DeletedAddrLabelsNeedingEmission;



public:

  MMIAddrLabelMap(MCContext &context) : Context(context) {}



  ~MMIAddrLabelMap() {

    assert(DeletedAddrLabelsNeedingEmission.empty() &&

           "Some labels for deleted blocks never got emitted");

  }



  ArrayRef<MCSymbol *> getAddrLabelSymbolToEmit(BasicBlock *BB);



  void takeDeletedSymbolsForFunction(Function *F,

                                     std::vector<MCSymbol*> &Result);



  void UpdateForDeletedBlock(BasicBlock *BB);

  void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);

};
@@ -132,20 +118,6 @@ ArrayRef<MCSymbol *> MMIAddrLabelMap::getAddrLabelSymbolToEmit(BasicBlock *BB) { 
  return Entry.Symbols;

}



/// If we have any deleted symbols for F, return them.

void MMIAddrLabelMap::

takeDeletedSymbolsForFunction(Function *F, std::vector<MCSymbol*> &Result) {

  DenseMap<AssertingVH<Function>, std::vector<MCSymbol*>>::iterator I =

    DeletedAddrLabelsNeedingEmission.find(F);



  // If there are no entries for the function, just return.

  if (I == DeletedAddrLabelsNeedingEmission.end()) return;



  // Otherwise, take the list.

  std::swap(Result, I->second);

  DeletedAddrLabelsNeedingEmission.erase(I);

}



void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) {

  // If the block got deleted, there is no need for the symbol.  If the symbol

  // was already emitted, we can just forget about it, otherwise we need to
@@ -158,16 +130,8 @@ void MMIAddrLabelMap::UpdateForDeletedBlock(BasicBlock *BB) { 
  assert((BB->getParent() == nullptr || BB->getParent() == Entry.Fn) &&

         "Block/parent mismatch");



  for (MCSymbol *Sym : Entry.Symbols) {

    if (Sym->isDefined())

      return;



    // If the block is not yet defined, we need to emit it at the end of the

    // function.  Add the symbol to the DeletedAddrLabelsNeedingEmission list

    // for the containing Function.  Since the block is being deleted, its

    // parent may already be removed, we have to get the function from 'Entry'.

    DeletedAddrLabelsNeedingEmission[Entry.Fn].push_back(Sym);

  }

  assert(llvm::all_of(Entry.Symbols, [](MCSymbol *Sym) {

    return Sym->isDefined(); }));

}



void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
@@ -252,15 +216,6 @@ MachineModuleInfo::getAddrLabelSymbolToEmit(const BasicBlock *BB) { 
 return AddrLabelSymbols->getAddrLabelSymbolToEmit(const_cast<BasicBlock*>(BB));

}



void MachineModuleInfo::

takeDeletedSymbolsForFunction(const Function *F,

                              std::vector<MCSymbol*> &Result) {

  // If no blocks have had their addresses taken, we're done.

  if (!AddrLabelSymbols) return;

  return AddrLabelSymbols->

     takeDeletedSymbolsForFunction(const_cast<Function*>(F), Result);

}



/// \name Exception Handling

/// \{