Fix the case when a reference to an address taken BB is emitted in one

function, then the BB is RAUW'd before the definition is emitted.  There
are still two cases not being handled, but this should improve us back to
the situation before I touched anything.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98566 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 110 insertions, 6 deletions

diff --git a/lib/CodeGen/MachineModuleInfo.cpp b/lib/CodeGen/MachineModuleInfo.cpp
index a23cc1a877..72a9450dcb 100644
--- a/lib/CodeGen/MachineModuleInfo.cpp
+++ b/lib/CodeGen/MachineModuleInfo.cpp
@@ -36,6 +36,99 @@ char MachineModuleInfo::ID = 0;
 // Out of line virtual method.
 MachineModuleInfoImpl::~MachineModuleInfoImpl() {}
 
+namespace llvm {
+class MMIAddrLabelMapCallbackPtr : CallbackVH {
+  MMIAddrLabelMap *Map;
+public:
+  MMIAddrLabelMapCallbackPtr() : Map(0) {}
+  MMIAddrLabelMapCallbackPtr(Value *V) : CallbackVH(V), Map(0) {}
+  
+  void setMap(MMIAddrLabelMap *map) { Map = map; }
+  
+  virtual void deleted();
+  virtual void allUsesReplacedWith(Value *V2);
+};
+  
+class MMIAddrLabelMap {
+  MCContext &Context;
+  struct AddrLabelSymEntry {
+    MCSymbol *Sym;
+    unsigned Index;
+  };
+  
+  DenseMap<AssertingVH<BasicBlock>, AddrLabelSymEntry> AddrLabelSymbols;
+  
+  std::vector<MMIAddrLabelMapCallbackPtr> BBCallbacks;
+public:
+  
+  MMIAddrLabelMap(MCContext &context) : Context(context) {}
+  
+  MCSymbol *getAddrLabelSymbol(BasicBlock *BB);  
+  void UpdateForDeletedBlock(BasicBlock *BB);
+  void UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New);
+};
+}
+
+MCSymbol *MMIAddrLabelMap::getAddrLabelSymbol(BasicBlock *BB) {
+  assert(BB->hasAddressTaken() &&
+         "Shouldn't get label for block without address taken");
+  AddrLabelSymEntry &Entry = AddrLabelSymbols[BB];
+  
+  // If we already had an entry for this block, just return it.
+  if (Entry.Sym) return Entry.Sym;
+  
+  // Otherwise, this is a new entry, create a new symbol for it and add an
+  // entry to BBCallbacks so we can be notified if the BB is deleted or RAUWd.
+  BBCallbacks.push_back(BB);
+  BBCallbacks.back().setMap(this);
+  Entry.Index = BBCallbacks.size()-1;
+  return Entry.Sym = Context.CreateTempSymbol();
+}
+
+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
+  // queue it up for later emission when the function is output.
+  AddrLabelSymEntry Entry = AddrLabelSymbols[BB];
+  AddrLabelSymbols.erase(BB);
+  assert(Entry.Sym && "Didn't have a symbol, why a callback?");
+  BBCallbacks[Entry.Index] = 0;  // Clear the callback.
+
+  if (Entry.Sym->isDefined())
+    return;
+  
+  // If the block is not yet defined, we need to emit it at the end of the
+  // function.
+  assert(0 && "Case not handled yet!");
+  abort();
+}
+
+void MMIAddrLabelMap::UpdateForRAUWBlock(BasicBlock *Old, BasicBlock *New) {
+  // Get the entry for the RAUW'd block and remove it from our map.
+  AddrLabelSymEntry OldEntry = AddrLabelSymbols[Old];
+  AddrLabelSymbols.erase(Old);
+  assert(OldEntry.Sym && "Didn't have a symbol, why a callback?");
+  
+  // If New is not address taken, just move our symbol over to it.
+  if (!AddrLabelSymbols.count(New)) {
+    BBCallbacks[OldEntry.Index] = New;    // Update the callback.
+    AddrLabelSymbols[New] = OldEntry;     // Set New's entry.
+  } else {
+    assert(0 && "Case not handled yet!");
+    abort();
+  }
+}
+
+
+void MMIAddrLabelMapCallbackPtr::deleted() {
+  Map->UpdateForDeletedBlock(cast<BasicBlock>(getValPtr()));
+}
+
+void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
+  Map->UpdateForRAUWBlock(cast<BasicBlock>(getValPtr()), cast<BasicBlock>(V2));
+}
+
+
 //===----------------------------------------------------------------------===//
 
 MachineModuleInfo::MachineModuleInfo(const MCAsmInfo &MAI)
@@ -44,6 +137,7 @@ MachineModuleInfo::MachineModuleInfo(const MCAsmInfo &MAI)
   CurCallSite(0), CallsEHReturn(0), CallsUnwindInit(0), DbgInfoAvailable(false){
   // Always emit some info, by default "no personality" info.
   Personalities.push_back(NULL);
+  AddrLabelSymbols = 0;
 }
 
 MachineModuleInfo::MachineModuleInfo()
@@ -55,17 +149,25 @@ MachineModuleInfo::MachineModuleInfo()
 
 MachineModuleInfo::~MachineModuleInfo() {
   delete ObjFileMMI;
+  
+  // FIXME: Why isn't doFinalization being called??
+  //assert(AddrLabelSymbols == 0 && "doFinalization not called");
+  delete AddrLabelSymbols;
+  AddrLabelSymbols = 0;
 }
 
 /// doInitialization - Initialize the state for a new module.
 ///
 bool MachineModuleInfo::doInitialization() {
+  assert(AddrLabelSymbols == 0 && "Improperly initialized");
   return false;
 }
 
 /// doFinalization - Tear down the state after completion of a module.
 ///
 bool MachineModuleInfo::doFinalization() {
+  delete AddrLabelSymbols;
+  AddrLabelSymbols = 0;
   return false;
 }
 
@@ -104,19 +206,21 @@ void MachineModuleInfo::AnalyzeModule(Module &M) {
       UsedFunctions.insert(F);
 }
 
+//===- Address of Block Management ----------------------------------------===//
+
+
 /// getAddrLabelSymbol - Return the symbol to be used for the specified basic
 /// block when its address is taken.  This cannot be its normal LBB label
 /// because the block may be accessed outside its containing function.
 MCSymbol *MachineModuleInfo::getAddrLabelSymbol(const BasicBlock *BB) {
-  assert(BB->hasAddressTaken() &&
-         "Shouldn't get label for block without address taken");
-  MCSymbol *&Entry = AddrLabelSymbols[const_cast<BasicBlock*>(BB)];
-  if (Entry) return Entry;
-  return Entry = Context.CreateTempSymbol();
+  // Lazily create AddrLabelSymbols.
+  if (AddrLabelSymbols == 0)
+    AddrLabelSymbols = new MMIAddrLabelMap(Context);
+  return AddrLabelSymbols->getAddrLabelSymbol(const_cast<BasicBlock*>(BB));
 }
 
 
-//===-EH-------------------------------------------------------------------===//
+//===- EH -----------------------------------------------------------------===//
 
 /// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
 /// specified MachineBasicBlock.