Revert r279564. It introduces undefined behavior (binding a reference to a

dereferenced null pointer) in MachineModuleInfo::MachineModuleInfo that causes
-Werror builds (including several buildbots) to fail.

llvm-svn: 279580

llvm/lib/CodeGen/MachineModuleInfo.cpp

@@ -13,7 +13,6 @@
 #include "llvm/Analysis/EHPersonalities.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionInitializer.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/IR/Constants.h"
@@ -187,19 +186,15 @@ void MMIAddrLabelMapCallbackPtr::allUsesReplacedWith(Value *V2) {
 
 //===----------------------------------------------------------------------===//
 
-MachineModuleInfo::MachineModuleInfo(const TargetMachine &TM,
-                                     const MCAsmInfo &MAI,
+MachineModuleInfo::MachineModuleInfo(const MCAsmInfo &MAI,
                                      const MCRegisterInfo &MRI,
-                                     const MCObjectFileInfo *MOFI,
-                                     MachineFunctionInitializer *MFI)
-  : ImmutablePass(ID), TM(TM), Context(&MAI, &MRI, MOFI, nullptr, false),
-    MFInitializer(MFI) {
+                                     const MCObjectFileInfo *MOFI)
+  : ImmutablePass(ID), Context(&MAI, &MRI, MOFI, nullptr, false) {
   initializeMachineModuleInfoPass(*PassRegistry::getPassRegistry());
 }
 
 MachineModuleInfo::MachineModuleInfo()
-  : ImmutablePass(ID), TM(*((TargetMachine*)nullptr)),
-    Context(nullptr, nullptr, nullptr) {
+  : ImmutablePass(ID), Context(nullptr, nullptr, nullptr) {
   llvm_unreachable("This MachineModuleInfo constructor should never be called, "
                    "MMI should always be explicitly constructed by "
                    "LLVMTargetMachine");
@@ -218,7 +213,7 @@ bool MachineModuleInfo::doInitialization(Module &M) {
   DbgInfoAvailable = UsesVAFloatArgument = UsesMorestackAddr = false;
   PersonalityTypeCache = EHPersonality::Unknown;
   AddrLabelSymbols = nullptr;
-  TheModule = &M;
+  TheModule = nullptr;
 
   return false;
 }
@@ -466,63 +461,3 @@ try_next:;
   FilterIds.push_back(0); // terminator
   return FilterID;
 }
-
-MachineFunction &MachineModuleInfo::getMachineFunction(const Function &F) {
-  // Shortcut for the common case where a sequence of MachineFunctionPasses
-  // all query for the same Function.
-  if (LastRequest == &F)
-    return *LastResult;
-
-  auto I = MachineFunctions.insert(
-      std::make_pair(&F, std::unique_ptr<MachineFunction>()));
-  MachineFunction *MF;
-  if (I.second) {
-    // No pre-existing machine function, create a new one.
-    MF = new MachineFunction(&F, TM, NextFnNum++, *this);
-    // Update the set entry.
-    I.first->second.reset(MF);
-
-    if (MFInitializer)
-      if (MFInitializer->initializeMachineFunction(*MF))
-        report_fatal_error("Unable to initialize machine function");
-  } else {
-    MF = I.first->second.get();
-  }
-
-  LastRequest = &F;
-  LastResult = MF;
-  return *MF;
-}
-
-void MachineModuleInfo::deleteMachineFunctionFor(Function &F) {
-  MachineFunctions.erase(&F);
-  LastRequest = nullptr;
-  LastResult = nullptr;
-}
-
-namespace {
-/// This pass frees the MachineFunction object associated with a Function.
-class FreeMachineFunction : public FunctionPass {
-public:
-  static char ID;
-  FreeMachineFunction() : FunctionPass(ID) {}
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.addRequired<MachineModuleInfo>();
-    AU.addPreserved<MachineModuleInfo>();
-  }
-
-  bool runOnFunction(Function &F) override {
-    MachineModuleInfo &MMI = getAnalysis<MachineModuleInfo>();
-    MMI.deleteMachineFunctionFor(F);
-    return true;
-  }
-};
-char FreeMachineFunction::ID;
-} // end anonymous namespace
-
-namespace llvm {
-FunctionPass *createFreeMachineFunctionPass() {
-  return new FreeMachineFunction();
-}
-} // end namespace llvm