Rebased PNaCl localmods in LLVM to 223109

lib/Transforms/NaCl/ReplacePtrsWithInts.cpp

+//===- ReplacePtrsWithInts.cpp - Convert pointer values to integer values--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass strips out aggregate pointer types and replaces them with
+// the integer type iPTR, which is i32 for PNaCl (though this pass
+// will allow iPTR to be i64 if the DataLayout specifies 64-bit
+// pointers).
+//
+// This pass relies on -simplify-allocas to transform allocas into arrays of
+// bytes.
+//
+// The pass converts IR to the following normal form:
+//
+// All inttoptr and ptrtoint instructions use the same integer size
+// (iPTR), so they do not implicitly truncate or zero-extend.
+//
+// Pointer types only appear in the following instructions:
+//  * loads and stores:  the pointer operand is a NormalizedPtr.
+//  * function calls:  the function operand is a NormalizedPtr.
+//  * intrinsic calls:  any pointer arguments are NormalizedPtrs.
+//  * alloca
+//  * bitcast and inttoptr:  only used as part of a NormalizedPtr.
+//  * ptrtoint:  the operand is an InherentPtr.
+//
+// Where an InherentPtr is defined as a pointer value that is:
+//  * an alloca;
+//  * a GlobalValue (a function or global variable); or
+//  * an intrinsic call.
+//
+// And a NormalizedPtr is defined as a pointer value that is:
+//  * an inttoptr instruction;
+//  * an InherentPtr; or
+//  * a bitcast of an InherentPtr.
+//
+// This pass currently strips out lifetime markers (that is, calls to
+// the llvm.lifetime.start/end intrinsics) and invariant markers
+// (calls to llvm.invariant.start/end).
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/NaCl.h"
+
+using namespace llvm;
+
+namespace {
+  // This is a ModulePass because the pass must recreate functions in
+  // order to change their argument and return types.
+  struct ReplacePtrsWithInts : public ModulePass {
+    static char ID; // Pass identification, replacement for typeid
+    ReplacePtrsWithInts() : ModulePass(ID) {
+      initializeReplacePtrsWithIntsPass(*PassRegistry::getPassRegistry());
+    }
+
+    virtual bool runOnModule(Module &M);
+  };
+
+  // FunctionConverter stores the state for mapping old instructions
+  // (of pointer type) to converted instructions (of integer type)
+  // within a function, and provides methods for doing the conversion.
+  class FunctionConverter {
+    // Int type that pointer types are to be replaced with, typically i32.
+    Type *IntPtrType;
+
+    struct RewrittenVal {
+      RewrittenVal(): Placeholder(NULL), NewIntVal(NULL) {}
+      Value *Placeholder;
+      Value *NewIntVal;
+    };
+    // Maps from old values (of pointer type) to converted values (of
+    // IntPtrType type).
+    DenseMap<Value *, RewrittenVal> RewriteMap;
+
+  public:
+    FunctionConverter(Type *IntPtrType) : IntPtrType(IntPtrType) {}
+
+    // Returns the normalized version of the given type, converting
+    // pointer types to IntPtrType.
+    Type *convertType(Type *Ty);
+    // Returns the normalized version of the given function type by
+    // normalizing the function's argument types.
+    FunctionType *convertFuncType(FunctionType *FTy);
+
+    // Records that 'To' is the normalized version of 'From'.  If 'To'
+    // is not of pointer type, no type conversion is required, so this
+    // can take the short cut of replacing 'To' with 'From'.
+    void recordConverted(Value *From, Value *To);
+    void recordConvertedAndErase(Instruction *From, Value *To);
+
+    // Returns Val with no-op casts (those that convert between
+    // IntPtrType and pointer types) stripped off.
+    Value *stripNoopCasts(Value *Val);
+
+    // Returns the normalized version of the given value.
+    //
+    // If the conversion of Val has been deferred, this returns a
+    // placeholder object, which will later be replaceAllUsesWith'd to
+    // the final value.  Since replaceAllUsesWith does not work on
+    // references by metadata nodes, this can be bypassed using
+    // BypassPlaceholder to get the real converted value, assuming it
+    // is available.
+    Value *convert(Value *Val, bool BypassPlaceholder = false);
+    // Returns the NormalizedPtr form of the given pointer value.
+    // Inserts conversion instructions at InsertPt.
+    Value *convertBackToPtr(Value *Val, Instruction *InsertPt);
+    // Returns the NormalizedPtr form of the given function pointer.
+    // Inserts conversion instructions at InsertPt.
+    Value *convertFunctionPtr(Value *Callee, Instruction *InsertPt);
+    // Converts an instruction without recreating it, by wrapping its
+    // operands and result.
+    void convertInPlace(Instruction *Inst);
+
+    void eraseReplacedInstructions();
+
+    // List of instructions whose deletion has been deferred.
+    SmallVector<Instruction *, 20> ToErase;
+  };
+}
+
+Type *FunctionConverter::convertType(Type *Ty) {
+  if (Ty->isPointerTy())
+    return IntPtrType;
+  return Ty;
+}
+
+FunctionType *FunctionConverter::convertFuncType(FunctionType *FTy) {
+  SmallVector<Type *, 8> ArgTypes;
+  for (FunctionType::param_iterator ArgTy = FTy->param_begin(),
+           E = FTy->param_end(); ArgTy != E; ++ArgTy) {
+    ArgTypes.push_back(convertType(*ArgTy));
+  }
+  return FunctionType::get(convertType(FTy->getReturnType()), ArgTypes,
+                           FTy->isVarArg());
+}
+
+void FunctionConverter::recordConverted(Value *From, Value *To) {
+  if (!From->getType()->isPointerTy()) {
+    From->replaceAllUsesWith(To);
+    return;
+  }
+  RewrittenVal *RV = &RewriteMap[From];
+  assert(!RV->NewIntVal);
+  RV->NewIntVal = To;
+}
+
+void FunctionConverter::recordConvertedAndErase(Instruction *From, Value *To) {
+  recordConverted(From, To);
+  // There may still be references to this value, so defer deleting it.
+  ToErase.push_back(From);
+}
+
+Value *FunctionConverter::stripNoopCasts(Value *Val) {
+  SmallPtrSet<Value *, 4> Visited;
+  for (;;) {
+    if (!Visited.insert(Val).second) {
+      // It is possible to get a circular reference in unreachable
+      // basic blocks.  Handle this case for completeness.
+      return UndefValue::get(Val->getType());
+    }
+    if (CastInst *Cast = dyn_cast<CastInst>(Val)) {
+      Value *Src = Cast->getOperand(0);
+      if ((isa<BitCastInst>(Cast) && Cast->getType()->isPointerTy()) ||
+          (isa<PtrToIntInst>(Cast) && Cast->getType() == IntPtrType) ||
+          (isa<IntToPtrInst>(Cast) && Src->getType() == IntPtrType)) {
+        Val = Src;
+        continue;
+      }
+    }
+    return Val;
+  }
+}
+
+Value *FunctionConverter::convert(Value *Val, bool BypassPlaceholder) {
+  Val = stripNoopCasts(Val);
+  if (!Val->getType()->isPointerTy())
+    return Val;
+  if (Constant *C = dyn_cast<Constant>(Val))
+    return ConstantExpr::getPtrToInt(C, IntPtrType);
+  RewrittenVal *RV = &RewriteMap[Val];
+  if (BypassPlaceholder) {
+    assert(RV->NewIntVal);
+    return RV->NewIntVal;
+  }
+  if (!RV->Placeholder)
+    RV->Placeholder = new Argument(convertType(Val->getType()));
+  return RV->Placeholder;
+}
+
+Value *FunctionConverter::convertBackToPtr(Value *Val, Instruction *InsertPt) {
+  Type *NewTy =
+    convertType(Val->getType()->getPointerElementType())->getPointerTo();
+  return new IntToPtrInst(convert(Val), NewTy, "", InsertPt);
+}
+
+Value *FunctionConverter::convertFunctionPtr(Value *Callee,
+                                             Instruction *InsertPt) {
+  FunctionType *FuncType = cast<FunctionType>(
+      Callee->getType()->getPointerElementType());
+  return new IntToPtrInst(convert(Callee),
+                          convertFuncType(FuncType)->getPointerTo(),
+                          "", InsertPt);
+}
+
+static bool ShouldLeaveAlone(Value *V) {
+  if (Function *F = dyn_cast<Function>(V))
+    return F->isIntrinsic();
+  if (isa<InlineAsm>(V))
+    return true;
+  return false;
+}
+
+void FunctionConverter::convertInPlace(Instruction *Inst) {
+  // Convert operands.
+  for (unsigned I = 0; I < Inst->getNumOperands(); ++I) {
+    Value *Arg = Inst->getOperand(I);
+    if (Arg->getType()->isPointerTy() && !ShouldLeaveAlone(Arg)) {
+      Value *Conv = convert(Arg);
+      Inst->setOperand(I, new IntToPtrInst(Conv, Arg->getType(), "", Inst));
+    }
+  }
+  // Convert result.
+  if (Inst->getType()->isPointerTy()) {
+    Instruction *Cast = new PtrToIntInst(
+        Inst, convertType(Inst->getType()), Inst->getName() + ".asint");
+    Cast->insertAfter(Inst);
+    recordConverted(Inst, Cast);
+  }
+}
+
+void FunctionConverter::eraseReplacedInstructions() {
+  bool Error = false;
+  for (DenseMap<Value *, RewrittenVal>::iterator I = RewriteMap.begin(),
+           E = RewriteMap.end(); I != E; ++I) {
+    if (I->second.Placeholder) {
+      if (I->second.NewIntVal) {
+        I->second.Placeholder->replaceAllUsesWith(I->second.NewIntVal);
+      } else {
+        errs() << "Not converted: " << *I->first << "\n";
+        Error = true;
+      }
+    }
+  }
+  if (Error)
+    report_fatal_error("Case not handled in ReplacePtrsWithInts");
+
+  // Delete the placeholders in a separate pass.  This means that if
+  // one placeholder is accidentally rewritten to another, we will get
+  // a useful error message rather than accessing a dangling pointer.
+  for (DenseMap<Value *, RewrittenVal>::iterator I = RewriteMap.begin(),
+           E = RewriteMap.end(); I != E; ++I) {
+    delete I->second.Placeholder;
+  }
+
+  // We must do dropAllReferences() before doing eraseFromParent(),
+  // otherwise we will try to erase instructions that are still
+  // referenced.
+  for (SmallVectorImpl<Instruction *>::iterator I = ToErase.begin(),
+           E = ToErase.end();
+       I != E; ++I) {
+    (*I)->dropAllReferences();
+  }
+  for (SmallVectorImpl<Instruction *>::iterator I = ToErase.begin(),
+           E = ToErase.end();
+       I != E; ++I) {
+    (*I)->eraseFromParent();
+  }
+}
+
+static void ConvertMetadataOperand(FunctionConverter *FC,
+                                   IntrinsicInst *Call, int Index) {
+  MDNode *MD = cast<MDNode>(Call->getArgOperand(Index));
+  if (MD->getNumOperands() != 1)
+    return;
+  Value *MDArg = MD->getOperand(0);
+  if (MDArg && (isa<Argument>(MDArg) || isa<Instruction>(MDArg))) {
+    MDArg = FC->convert(MDArg, /* BypassPlaceholder= */ true);
+    if (PtrToIntInst *Cast = dyn_cast<PtrToIntInst>(MDArg)) {
+      // Unwrapping this is necessary for llvm.dbg.declare to work.
+      MDArg = Cast->getPointerOperand();
+    }
+    SmallVector<Value *, 1> Args;
+    Args.push_back(MDArg);
+    Call->setArgOperand(Index, MDNode::get(Call->getContext(), Args));
+  }
+}
+
+// Remove attributes that only apply to pointer arguments.  Returns
+// the updated AttributeSet.
+static AttributeSet RemovePointerAttrs(LLVMContext &Context,
+                                       AttributeSet Attrs) {
+  SmallVector<AttributeSet, 8> AttrList;
+  for (unsigned Slot = 0; Slot < Attrs.getNumSlots(); ++Slot) {
+    unsigned Index = Attrs.getSlotIndex(Slot);
+    AttrBuilder AB;
+    for (AttributeSet::iterator Attr = Attrs.begin(Slot), E = Attrs.end(Slot);
+         Attr != E; ++Attr) {
+      if (!Attr->isEnumAttribute()) {
+        continue;
+      }
+      switch (Attr->getKindAsEnum()) {
+        // ByVal and StructRet should already have been removed by the
+        // ExpandByVal pass.
+        case Attribute::ByVal:
+        case Attribute::StructRet:
+        case Attribute::Nest:
+          Attrs.dump();
+          report_fatal_error("ReplacePtrsWithInts cannot handle "
+                             "byval, sret or nest attrs");
+          break;
+        // Strip these attributes because they apply only to pointers. This pass
+        // rewrites pointer arguments, thus these parameter attributes are
+        // meaningless. Also, they are rejected by the PNaCl module verifier.
+        case Attribute::NoCapture:
+        case Attribute::NoAlias:
+        case Attribute::ReadNone:
+        case Attribute::ReadOnly:
+          break;
+        default:
+          AB.addAttribute(*Attr);
+      }
+    }
+    AttrList.push_back(AttributeSet::get(Context, Index, AB));
+  }
+  return AttributeSet::get(Context, AttrList);
+}
+
+static void ConvertInstruction(DataLayout *DL, Type *IntPtrType,
+                               FunctionConverter *FC, Instruction *Inst) {
+  if (ReturnInst *Ret = dyn_cast<ReturnInst>(Inst)) {
+    Value *Result = Ret->getReturnValue();
+    if (Result)
+      Result = FC->convert(Result);
+    CopyDebug(ReturnInst::Create(Ret->getContext(), Result, Ret), Inst);
+    Ret->eraseFromParent();
+  } else if (PHINode *Phi = dyn_cast<PHINode>(Inst)) {
+    PHINode *Phi2 = PHINode::Create(FC->convertType(Phi->getType()),
+                                    Phi->getNumIncomingValues(),
+                                    "", Phi);
+    CopyDebug(Phi2, Phi);
+    for (unsigned I = 0; I < Phi->getNumIncomingValues(); ++I) {
+      Phi2->addIncoming(FC->convert(Phi->getIncomingValue(I)),
+                        Phi->getIncomingBlock(I));
+    }
+    Phi2->takeName(Phi);
+    FC->recordConvertedAndErase(Phi, Phi2);
+  } else if (SelectInst *Op = dyn_cast<SelectInst>(Inst)) {
+    Instruction *Op2 = SelectInst::Create(Op->getCondition(),
+                                          FC->convert(Op->getTrueValue()),
+                                          FC->convert(Op->getFalseValue()),
+                                          "", Op);
+    CopyDebug(Op2, Op);
+    Op2->takeName(Op);
+    FC->recordConvertedAndErase(Op, Op2);
+  } else if (isa<PtrToIntInst>(Inst) || isa<IntToPtrInst>(Inst)) {
+    Value *Arg = FC->convert(Inst->getOperand(0));
+    Type *ResultTy = FC->convertType(Inst->getType());
+    unsigned ArgSize = Arg->getType()->getIntegerBitWidth();
+    unsigned ResultSize = ResultTy->getIntegerBitWidth();
+    Value *Result;
+    // We avoid using IRBuilder's CreateZExtOrTrunc() here because it
+    // constant-folds ptrtoint ConstantExprs.  This leads to creating
+    // ptrtoints of non-IntPtrType type, which is not what we want,
+    // because we want truncation/extension to be done explicitly by
+    // separate instructions.
+    if (ArgSize == ResultSize) {
+      Result = Arg;
+    } else {
+      Instruction::CastOps CastType =
+          ArgSize > ResultSize ? Instruction::Trunc : Instruction::ZExt;
+      Result = CopyDebug(CastInst::Create(CastType, Arg, ResultTy, "", Inst),
+                         Inst);
+    }
+    if (Result != Arg)
+      Result->takeName(Inst);
+    FC->recordConvertedAndErase(Inst, Result);
+  } else if (isa<BitCastInst>(Inst)) {
+    if (Inst->getType()->isPointerTy()) {
+      FC->ToErase.push_back(Inst);
+    }
+  } else if (ICmpInst *Cmp = dyn_cast<ICmpInst>(Inst)) {
+    Value *Cmp2 = CopyDebug(new ICmpInst(Inst, Cmp->getPredicate(),
+                                         FC->convert(Cmp->getOperand(0)),
+                                         FC->convert(Cmp->getOperand(1)), ""),
+                            Inst);
+    Cmp2->takeName(Cmp);
+    Cmp->replaceAllUsesWith(Cmp2);
+    Cmp->eraseFromParent();
+  } else if (LoadInst *Load = dyn_cast<LoadInst>(Inst)) {
+    Value *Ptr = FC->convertBackToPtr(Load->getPointerOperand(), Inst);
+    LoadInst *Result = new LoadInst(Ptr, "", Inst);
+    Result->takeName(Inst);
+    CopyDebug(Result, Inst);
+    CopyLoadOrStoreAttrs(Result, Load);
+    FC->recordConvertedAndErase(Inst, Result);
+  } else if (StoreInst *Store = dyn_cast<StoreInst>(Inst)) {
+    Value *Ptr = FC->convertBackToPtr(Store->getPointerOperand(), Inst);
+    StoreInst *Result = new StoreInst(FC->convert(Store->getValueOperand()),
+                                      Ptr, Inst);
+    CopyDebug(Result, Inst);
+    CopyLoadOrStoreAttrs(Result, Store);
+    Inst->eraseFromParent();
+  } else if (CallInst *Call = dyn_cast<CallInst>(Inst)) {
+    if (IntrinsicInst *ICall = dyn_cast<IntrinsicInst>(Inst)) {
+      if (ICall->getIntrinsicID() == Intrinsic::lifetime_start ||
+          ICall->getIntrinsicID() == Intrinsic::lifetime_end ||
+          ICall->getIntrinsicID() == Intrinsic::invariant_start) {
+        // Remove alloca lifetime markers for now.  This is because
+        // the GVN pass can introduce lifetime markers taking PHI
+        // nodes as arguments.  If ReplacePtrsWithInts converts the
+        // PHI node to int type, we will render those lifetime markers
+        // ineffective.  But dropping a subset of lifetime markers is
+        // not safe in general.  So, until LLVM better defines the
+        // semantics of lifetime markers, we drop them all.  See:
+        // https://code.google.com/p/nativeclient/issues/detail?id=3443
+        // We do the same for invariant.start/end because they work in
+        // a similar way.
+        Inst->eraseFromParent();
+      } else {
+        FC->convertInPlace(Inst);
+      }
+    } else if (isa<InlineAsm>(Call->getCalledValue())) {
+      FC->convertInPlace(Inst);
+    } else {
+      SmallVector<Value *, 10> Args;
+      for (unsigned I = 0; I < Call->getNumArgOperands(); ++I)
+        Args.push_back(FC->convert(Call->getArgOperand(I)));
+      CallInst *NewCall = CallInst::Create(
+          FC->convertFunctionPtr(Call->getCalledValue(), Call),
+          Args, "", Inst);
+      CopyDebug(NewCall, Call);
+      NewCall->setAttributes(RemovePointerAttrs(Call->getContext(),
+                                                Call->getAttributes()));
+      NewCall->setCallingConv(Call->getCallingConv());
+      NewCall->setTailCall(Call->isTailCall());
+      NewCall->takeName(Call);
+      FC->recordConvertedAndErase(Call, NewCall);
+    }
+  } else if (InvokeInst *Call = dyn_cast<InvokeInst>(Inst)) {
+    SmallVector<Value *, 10> Args;
+    for (unsigned I = 0; I < Call->getNumArgOperands(); ++I)
+      Args.push_back(FC->convert(Call->getArgOperand(I)));
+    InvokeInst *NewCall = InvokeInst::Create(
+        FC->convertFunctionPtr(Call->getCalledValue(), Call),
+        Call->getNormalDest(),
+        Call->getUnwindDest(),
+        Args, "", Inst);
+    CopyDebug(NewCall, Call);
+    NewCall->setAttributes(RemovePointerAttrs(Call->getContext(),
+                                              Call->getAttributes()));
+    NewCall->setCallingConv(Call->getCallingConv());
+    NewCall->takeName(Call);
+    FC->recordConvertedAndErase(Call, NewCall);
+  } else if (// Handle these instructions as a convenience to allow
+             // the pass to be used in more situations, even though we
+             // don't expect them in PNaCl's stable ABI.
+             isa<AllocaInst>(Inst) ||
+             isa<GetElementPtrInst>(Inst) ||
+             isa<VAArgInst>(Inst) ||
+             isa<IndirectBrInst>(Inst) ||
+             isa<ExtractValueInst>(Inst) ||
+             isa<InsertValueInst>(Inst) ||
+             // These atomics only operate on integer pointers, not
+             // other pointers, so we don't need to recreate the
+             // instruction.
+             isa<AtomicCmpXchgInst>(Inst) ||
+             isa<AtomicRMWInst>(Inst)) {
+    FC->convertInPlace(Inst);
+  }
+}
+
+// Convert ptrtoint+inttoptr to a bitcast because it's shorter and
+// because some intrinsics work on bitcasts but not on
+// ptrtoint+inttoptr, in particular:
+//  * llvm.lifetime.start/end (although we strip these out)
+//  * llvm.eh.typeid.for
+static void SimplifyCasts(Instruction *Inst, Type *IntPtrType) {
+  if (IntToPtrInst *Cast1 = dyn_cast<IntToPtrInst>(Inst)) {
+    if (PtrToIntInst *Cast2 = dyn_cast<PtrToIntInst>(Cast1->getOperand(0))) {
+      assert(Cast2->getType() == IntPtrType);
+      Value *V = Cast2->getPointerOperand();
+      if (V->getType() != Cast1->getType())
+        V = new BitCastInst(V, Cast1->getType(), V->getName() + ".bc", Cast1);
+      Cast1->replaceAllUsesWith(V);
+      if (Cast1->use_empty())
+        Cast1->eraseFromParent();
+      if (Cast2->use_empty())
+        Cast2->eraseFromParent();
+    }
+  }
+}
+
+static void CleanUpFunction(Function *Func, Type *IntPtrType) {
+  // Remove the ptrtoint/bitcast ConstantExprs we introduced for
+  // referencing globals.
+  FunctionPass *Pass = createExpandConstantExprPass();
+  Pass->runOnFunction(*Func);
+  delete Pass;
+
+  for (Function::iterator BB = Func->begin(), E = Func->end();
+       BB != E; ++BB) {
+    for (BasicBlock::iterator Iter = BB->begin(), E = BB->end();
+         Iter != E; ) {
+      SimplifyCasts(Iter++, IntPtrType);
+    }
+  }
+  // Cleanup pass.
+  for (Function::iterator BB = Func->begin(), E = Func->end();
+       BB != E; ++BB) {
+    for (BasicBlock::iterator Iter = BB->begin(), E = BB->end();
+         Iter != E; ) {
+      Instruction *Inst = Iter++;
+      // Add names to inttoptrs to make the output more readable.  The
+      // placeholder values get in the way of doing this earlier when
+      // the inttoptrs are created.
+      if (isa<IntToPtrInst>(Inst))
+        Inst->setName(Inst->getOperand(0)->getName() + ".asptr");
+      // Remove ptrtoints that were introduced for allocas but not used.
+      if (isa<PtrToIntInst>(Inst) && Inst->use_empty())
+        Inst->eraseFromParent();
+    }
+  }
+}
+
+char ReplacePtrsWithInts::ID = 0;
+INITIALIZE_PASS(ReplacePtrsWithInts, "replace-ptrs-with-ints",
+                "Convert pointer values to integer values",
+                false, false)
+
+bool ReplacePtrsWithInts::runOnModule(Module &M) {
+  DataLayout DL(&M);
+  DenseMap<const Function *, DISubprogram> FunctionDIs = makeSubprogramMap(M);
+  Type *IntPtrType = DL.getIntPtrType(M.getContext());
+
+  for (Module::iterator Iter = M.begin(), E = M.end(); Iter != E; ) {
+    Function *OldFunc = Iter++;
+    // Intrinsics' types must be left alone.
+    if (OldFunc->isIntrinsic())
+      continue;
+
+    FunctionConverter FC(IntPtrType);
+    FunctionType *NFTy = FC.convertFuncType(OldFunc->getFunctionType());
+    OldFunc->setAttributes(RemovePointerAttrs(M.getContext(),
+                                              OldFunc->getAttributes()));
+    Function *NewFunc = RecreateFunction(OldFunc, NFTy);
+
+    // Move the arguments across to the new function.
+    for (Function::arg_iterator Arg = OldFunc->arg_begin(),
+             E = OldFunc->arg_end(), NewArg = NewFunc->arg_begin();
+         Arg != E; ++Arg, ++NewArg) {
+      FC.recordConverted(Arg, NewArg);
+      NewArg->takeName(Arg);
+    }
+
+    // invariant.end calls refer to invariant.start calls, so we must
+    // remove the former first.
+    for (Function::iterator BB = NewFunc->begin(), E = NewFunc->end();
+         BB != E; ++BB) {
+      for (BasicBlock::iterator Iter = BB->begin(), E = BB->end();
+           Iter != E; ) {
+        if (IntrinsicInst *ICall = dyn_cast<IntrinsicInst>(Iter++)) {
+          if (ICall->getIntrinsicID() == Intrinsic::invariant_end)
+            ICall->eraseFromParent();
+        }
+      }
+    }
+
+    // Convert the function body.
+    for (Function::iterator BB = NewFunc->begin(), E = NewFunc->end();
+         BB != E; ++BB) {
+      for (BasicBlock::iterator Iter = BB->begin(), E = BB->end();
+           Iter != E; ) {
+        ConvertInstruction(&DL, IntPtrType, &FC, Iter++);
+      }
+    }
+    // Now that all the replacement instructions have been created, we
+    // can update the debug intrinsic calls.
+    for (Function::iterator BB = NewFunc->begin(), E = NewFunc->end();
+         BB != E; ++BB) {
+      for (BasicBlock::iterator Inst = BB->begin(), E = BB->end();
+           Inst != E; ++Inst) {
+        if (IntrinsicInst *Call = dyn_cast<IntrinsicInst>(Inst)) {
+          if (Call->getIntrinsicID() == Intrinsic::dbg_declare) {
+            ConvertMetadataOperand(&FC, Call, 0);
+          }
+        }
+      }
+    }
+    FC.eraseReplacedInstructions();
+
+    // Patch the pointer to LLVM function in debug info descriptor.
+    auto DI = FunctionDIs.find(OldFunc);
+    if (DI != FunctionDIs.end())
+      DI->second.replaceFunction(NewFunc);
+
+    OldFunc->eraseFromParent();
+  }
+  // Now that all functions have their normalized types, we can remove
+  // various casts.
+  for (Module::iterator Func = M.begin(), E = M.end(); Func != E; ++Func) {
+    CleanUpFunction(Func, IntPtrType);
+    // Delete the now-unused bitcast ConstantExprs that we created so
+    // that they don't interfere with StripDeadPrototypes.
+    Func->removeDeadConstantUsers();
+  }
+  return true;
+}
+
+ModulePass *llvm::createReplacePtrsWithIntsPass() {
+  return new ReplacePtrsWithInts();
+}