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

include/llvm/CodeGen/MachineModuleInfo.h

@@ -88,6 +88,8 @@ struct LandingPadInfo {
     : LandingPadBlock(MBB), LandingPadLabel(0), Personality(0) {}
 };
 
+class MMIAddrLabelMap;
+  
 //===----------------------------------------------------------------------===//
 /// MachineModuleInfo - This class contains meta information specific to a
 /// module.  Queries can be made by different debugging and exception handling 
@@ -142,7 +144,7 @@ class MachineModuleInfo : public ImmutablePass {
   
   /// AddrLabelSymbols - This map keeps track of which symbol is being used for
   /// the specified basic block's address of label.
-  DenseMap<AssertingVH<BasicBlock>, MCSymbol*> AddrLabelSymbols;
+  MMIAddrLabelMap *AddrLabelSymbols;
   
   bool CallsEHReturn;
   bool CallsUnwindInit;

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() &&
+  // Lazily create AddrLabelSymbols.
-         "Shouldn't get label for block without address taken");
+  if (AddrLabelSymbols == 0)
-  MCSymbol *&Entry = AddrLabelSymbols[const_cast<BasicBlock*>(BB)];
+    AddrLabelSymbols = new MMIAddrLabelMap(Context);
-  if (Entry) return Entry;
+  return AddrLabelSymbols->getAddrLabelSymbol(const_cast<BasicBlock*>(BB));
-  return Entry = Context.CreateTempSymbol();
 }
 
 
-//===-EH-------------------------------------------------------------------===//
+//===- EH -----------------------------------------------------------------===//
 
 /// getOrCreateLandingPadInfo - Find or create an LandingPadInfo for the
 /// specified MachineBasicBlock.

test/CodeGen/X86/crash.ll

@@ -90,3 +90,28 @@ foo:
   store i8 %8, i8* undef, align 1
   ret void
 }
+
+
+;; Issues with referring to a label that gets RAUW'd later.
+define i32 @test6a() nounwind {
+entry:
+	%target = bitcast i8* blockaddress(@test6b, %test_label) to i8*
+
+	call i32 @test6b(i8* %target)
+
+	ret i32 0
+}
+
+define i32 @test6b(i8* %target) nounwind {
+entry:
+	indirectbr i8* %target, [label %test_label]
+
+test_label:
+; assume some code here...
+	br label %ret
+
+ret:
+	ret i32 -1
+}
+
+