Initial checkin of structure mutator

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1246 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 501 insertions, 0 deletions

diff --git a/lib/Transforms/IPO/MutateStructTypes.cpp b/lib/Transforms/IPO/MutateStructTypes.cpp
new file mode 100644
index 0000000..1904842
--- /dev/null
+++ b/lib/Transforms/IPO/MutateStructTypes.cpp
@@ -0,0 +1,501 @@
+//===- MutateStructTypes.cpp - Change struct defns --------------------------=//
+//
+// This pass is used to change structure accesses and type definitions in some
+// way.  It can be used to arbitrarily permute structure fields, safely, without
+// breaking code.  A transformation may only be done on a type if that type has
+// been found to be "safe" by the 'FindUnsafePointerTypes' pass.  This pass will
+// assert and die if you try to do an illegal transformation.
+//
+// This is an interprocedural pass that requires the entire program to do a
+// transformation.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/MutateStructTypes.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Method.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/SymbolTable.h"
+#include "llvm/iOther.h"
+#include "llvm/iMemory.h"
+#include "llvm/iTerminators.h"
+#include <algorithm>
+
+// To enable debugging, uncomment this...
+//#define DEBUG_MST(x) x
+
+#ifdef DEBUG_MST
+#include "llvm/Assembly/Writer.h"
+#else
+#define DEBUG_MST(x)   // Disable debug code
+#endif
+
+// ValuePlaceHolder - A stupid little marker value.  It appears as an
+// instruction of type Instruction::UserOp1.
+//
+struct ValuePlaceHolder : public Instruction {
+  ValuePlaceHolder(const Type *Ty) : Instruction(Ty, UserOp1, "") {}
+
+  virtual Instruction *clone() const { abort(); }
+  virtual const char *getOpcodeName() const { return "placeholder"; }
+};
+
+
+// ConvertType - Convert from the old type system to the new one...
+const Type *MutateStructTypes::ConvertType(const Type *Ty) {
+  if (Ty->isPrimitiveType() ||
+      isa<OpaqueType>(Ty)) return Ty;  // Don't convert primitives
+
+  map<const Type *, PATypeHolder<Type> >::iterator I = TypeMap.find(Ty);
+  if (I != TypeMap.end()) return I->second;
+
+  const Type *DestTy = 0;
+
+  PATypeHolder<Type> PlaceHolder = OpaqueType::get();
+  TypeMap.insert(make_pair(Ty, PlaceHolder.get()));
+
+  switch (Ty->getPrimitiveID()) {
+  case Type::MethodTyID: {
+    const MethodType *MT = cast<MethodType>(Ty);
+    const Type *RetTy = ConvertType(MT->getReturnType());
+    vector<const Type*> ArgTypes;
+
+    for (MethodType::ParamTypes::const_iterator I = MT->getParamTypes().begin(),
+           E = MT->getParamTypes().end(); I != E; ++I)
+      ArgTypes.push_back(ConvertType(*I));
+    
+    DestTy = MethodType::get(RetTy, ArgTypes, MT->isVarArg());
+    break;
+  }
+  case Type::StructTyID: {
+    const StructType *ST = cast<StructType>(Ty);
+    const StructType::ElementTypes &El = ST->getElementTypes();
+    vector<const Type *> Types;
+
+    for (StructType::ElementTypes::const_iterator I = El.begin(), E = El.end();
+         I != E; ++I)
+      Types.push_back(ConvertType(*I));
+    DestTy = StructType::get(Types);
+    break;
+  }
+  case Type::ArrayTyID:
+    DestTy = ArrayType::get(ConvertType(cast<ArrayType>(Ty)->getElementType()),
+                            cast<ArrayType>(Ty)->getNumElements());
+    break;
+
+  case Type::PointerTyID:
+    DestTy = PointerType::get(
+                 ConvertType(cast<PointerType>(Ty)->getValueType()));
+    break;
+  default:
+    assert(0 && "Unknown type!");
+    return 0;
+  }
+
+  assert(DestTy && "Type didn't get created!?!?");
+
+  // Refine our little placeholder value into a real type...
+  cast<DerivedType>(PlaceHolder.get())->refineAbstractTypeTo(DestTy);
+  TypeMap.insert(make_pair(Ty, PlaceHolder.get()));
+
+  return PlaceHolder.get();
+}
+
+
+// AdjustIndices - Convert the indexes specifed by Idx to the new changed form
+// using the specified OldTy as the base type being indexed into.
+//
+void MutateStructTypes::AdjustIndices(const StructType *OldTy,
+                                      vector<ConstPoolVal*> &Idx,
+                                      unsigned i = 0) {
+  assert(i < Idx.size() && "i out of range!");
+  const StructType *NewST = cast<StructType>(ConvertType(OldTy));
+  if (NewST == OldTy) return;  // No adjustment unless type changes
+
+  // Figure out what the current index is...
+  unsigned ElNum = cast<ConstPoolUInt>(Idx[i])->getValue();
+  assert(ElNum < OldTy->getElementTypes().size());
+
+  map<const StructType*, TransformType>::iterator I = Transforms.find(OldTy);
+  if (I != Transforms.end()) {
+    assert(ElNum < I->second.second.size());
+    // Apply the XForm specified by Transforms map...
+    unsigned NewElNum = I->second.second[ElNum];
+    Idx[i] = ConstPoolUInt::get(Type::UByteTy, NewElNum);
+  }
+
+  // Recursively process subtypes...
+  if (i+1 < Idx.size())
+    AdjustIndices(cast<StructType>(OldTy->getElementTypes()[ElNum].get()),
+                  Idx, i+1);
+}
+
+
+// ConvertValue - Convert from the old value in the old type system to the new
+// type system.
+//
+Value *MutateStructTypes::ConvertValue(const Value *V) {
+  // Ignore null values and simple constants..
+  if (V == 0) return 0;
+
+  if (ConstPoolVal *CPV = dyn_cast<ConstPoolVal>(V)) {
+    if (V->getType()->isPrimitiveType())
+      return CPV;
+
+    if (isa<ConstPoolPointerNull>(CPV))
+      return ConstPoolPointerNull::get(
+                      cast<PointerType>(ConvertType(V->getType())));
+    assert(0 && "Unable to convert constpool val of this type!");
+  }
+
+  // Check to see if this is an out of method reference first...
+  if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
+    // Check to see if the value is in the map...
+    map<const GlobalValue*, GlobalValue*>::iterator I = GlobalMap.find(GV);
+    if (I == GlobalMap.end())
+      return GV;  // Not mapped, just return value itself
+    return I->second;
+  }
+  
+  map<const Value*, Value*>::iterator I = LocalValueMap.find(V);
+  if (I != LocalValueMap.end()) return I->second;
+
+  if (const BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
+    // Create placeholder block to represent the basic block we haven't seen yet
+    // This will be used when the block gets created.
+    //
+    return LocalValueMap[V] = new BasicBlock(BB->getName());
+  }
+
+  DEBUG_MST(cerr << "NPH: " << V << endl);
+
+  // Otherwise make a constant to represent it
+  return LocalValueMap[V] = new ValuePlaceHolder(ConvertType(V->getType()));
+}
+
+
+// Ctor - Take a map that specifies what transformation to do for each field
+// of the specified structure types.  There is one element of the vector for
+// each field of the structure.  The value specified indicates which slot of
+// the destination structure the field should end up in.  A negative value 
+// indicates that the field should be deleted entirely.
+//
+MutateStructTypes::MutateStructTypes(const map<const StructType*,
+                                               vector<int> > &XForm) {
+
+  // Loop over the types and insert dummy entries into the type map so that 
+  // recursive types are resolved properly...
+  for (map<const StructType*, vector<int> >::const_iterator I = XForm.begin(),
+         E = XForm.end(); I != E; ++I) {
+    const StructType *OldTy = I->first;
+    TypeMap.insert(make_pair(OldTy, OpaqueType::get()));
+  }
+
+  // Loop over the type specified and figure out what types they should become
+  for (map<const StructType*, vector<int> >::const_iterator I = XForm.begin(),
+         E = XForm.end(); I != E; ++I) {
+    const StructType  *OldTy = I->first;
+    const vector<int> &InVec = I->second;
+
+    assert(OldTy->getElementTypes().size() == InVec.size() &&
+           "Action not specified for every element of structure type!");
+
+    vector<const Type *> NewType;
+
+    // Convert the elements of the type over, including the new position mapping
+    int Idx = 0;
+    vector<int>::const_iterator TI = find(InVec.begin(), InVec.end(), Idx);
+    while (TI != InVec.end()) {
+      unsigned Offset = TI-InVec.begin();
+      const Type *NewEl = ConvertType(OldTy->getContainedType(Offset));
+      assert(NewEl && "Element not found!");
+      NewType.push_back(NewEl);
+
+      TI = find(InVec.begin(), InVec.end(), ++Idx);
+    }
+
+    // Create a new type that corresponds to the destination type
+    PATypeHolder<StructType> NSTy = StructType::get(NewType);
+
+    // Refine the old opaque type to the new type to properly handle recursive
+    // types...
+    //
+    const Type *OldTypeStub = TypeMap.find(OldTy)->second.get();
+    cast<DerivedType>(OldTypeStub)->refineAbstractTypeTo(NSTy);
+
+    // Add the transformation to the Transforms map.
+    Transforms.insert(make_pair(OldTy, make_pair(NSTy, InVec)));
+
+    DEBUG_MST(cerr << "Mutate " << OldTy << "\nTo " << NSTy << endl);
+  }
+}
+
+
+// doPassInitialization - This loops over global constants defined in the
+// module, converting them to their new type.
+//
+bool MutateStructTypes::doPassInitialization(Module *M) {
+  // Loop through the methods in the module and create a new version of the
+  // method to contained the transformed code.  Don't use an iterator, because
+  // we will be adding values to the end of the vector, and it could be
+  // reallocated.  Also, we don't want to process the values that we add.
+  //
+  unsigned NumMethods = M->size();
+  for (unsigned i = 0; i < NumMethods; ++i) {
+    Method *Meth = M->begin()[i];
+
+    if (!Meth->isExternal()) {
+      const MethodType *NewMTy = 
+        cast<MethodType>(ConvertType(Meth->getMethodType()));
+      
+      // Create a new method to put stuff into...
+      Method *NewMeth = new Method(NewMTy, Meth->getName());
+      if (Meth->hasName())
+        Meth->setName("OLD."+Meth->getName());
+
+      // Insert the new method into the method list... to be filled in later...
+      M->getMethodList().push_back(NewMeth);
+      
+      // Keep track of the association...
+      GlobalMap[Meth] = NewMeth;
+    }
+  }
+
+  // TODO: HANDLE GLOBAL VARIABLES
+
+  // Remap the symbol table to refer to the types in a nice way
+  //
+  if (M->hasSymbolTable()) {
+    SymbolTable *ST = M->getSymbolTable();
+    SymbolTable::iterator I = ST->find(Type::TypeTy);
+    if (I != ST->end()) {    // Get the type plane for Type's
+      SymbolTable::VarMap &Plane = I->second;
+      for (SymbolTable::type_iterator TI = Plane.begin(), TE = Plane.end();
+           TI != TE; ++TI) {
+        // This is gross, I'm reaching right into a symbol table and mucking
+        // around with it's internals... but oh well.
+        //
+        TI->second = cast<Type>(ConvertType(cast<Type>(TI->second)));
+      }
+    }
+  }
+
+  return true;
+}
+
+
+// doPassFinalization - For this pass, all this does is remove the old versions
+// of the methods and global variables that we no longer need.
+bool MutateStructTypes::doPassFinalization(Module *M) {
+  // The first half of the methods in the module have to go.
+  unsigned NumMethods = M->size();
+  unsigned NumGVars   = M->gsize();
+  assert((NumMethods & 1) == 0 && "Number of methods is odd!");
+
+  // Prepare for deletion of globals by dropping their interdependencies...
+  for(Module::iterator I = M->begin(); I != M->end(); ++I) {
+    if (GlobalMap.find(*I) != GlobalMap.end())
+      (*I)->Method::dropAllReferences();
+  }
+
+  // Run through and delete the methods and global variables...
+#if 0  // TODO: HANDLE GLOBAL VARIABLES
+  M->getGlobalList().delete_span(M->gbegin(), M->gbegin()+NumGVars/2);
+#endif
+  for(Module::iterator I = M->begin(); I != M->end();) {
+    if (GlobalMap.find(*I) != GlobalMap.end())
+      delete M->getMethodList().remove(I);
+    else
+      ++I;
+  }
+  
+  return true;
+}
+
+
+
+// doPerMethodWork - This transforms the instructions of the method to use the
+// new types.
+//
+bool MutateStructTypes::doPerMethodWork(Method *m) {
+  const Method *M = m;
+  map<const GlobalValue*, GlobalValue*>::iterator GMI = GlobalMap.find(M);
+  if (GMI == GlobalMap.end())
+    return false;  // Do not affect one of our new methods that we are creating
+
+  Method *NewMeth = cast<Method>(GMI->second);
+
+  // Okay, first order of business, create the arguments...
+  for (unsigned i = 0; i < M->getArgumentList().size(); ++i) {
+    const MethodArgument *OMA = M->getArgumentList()[i];
+    MethodArgument *NMA = new MethodArgument(ConvertType(OMA->getType()),
+                                             OMA->getName());
+    NewMeth->getArgumentList().push_back(NMA);
+    LocalValueMap[OMA] = NMA; // Keep track of value mapping
+  }
+
+
+  // Loop over all of the basic blocks copying instructions over...
+  for (Method::const_iterator BBI = M->begin(), BBE = M->end(); BBI != BBE;
+       ++BBI) {
+
+    // Create a new basic block and establish a mapping between the old and new
+    const BasicBlock *BB = *BBI;
+    BasicBlock *NewBB = cast<BasicBlock>(ConvertValue(BB));
+    NewMeth->getBasicBlocks().push_back(NewBB);  // Add block to method
+
+    // Copy over all of the instructions in the basic block...
+    for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
+         II != IE; ++II) {
+
+      const Instruction *I = *II;   // Get the current instruction...
+      Instruction *NewI = 0;
+
+      switch (I->getOpcode()) {
+        // Terminator Instructions
+      case Instruction::Ret:
+        NewI = new ReturnInst(
+                   ConvertValue(cast<ReturnInst>(I)->getReturnValue()));
+        break;
+      case Instruction::Br: {
+        const BranchInst *BI = cast<BranchInst>(I);
+        NewI = new BranchInst(
+                           cast<BasicBlock>(ConvertValue(BI->getSuccessor(0))),
+                    cast_or_null<BasicBlock>(ConvertValue(BI->getSuccessor(1))),
+                              ConvertValue(BI->getCondition()));
+        break;
+      }
+      case Instruction::Switch:
+      case Instruction::Invoke:
+        assert(0 && "Insn not implemented!");
+
+        // Unary Instructions
+      case Instruction::Not:
+        NewI = UnaryOperator::create((Instruction::UnaryOps)I->getOpcode(),
+                                     ConvertValue(I->getOperand(0)));
+        break;
+
+        // Binary Instructions
+      case Instruction::Add:
+      case Instruction::Sub:
+      case Instruction::Mul:
+      case Instruction::Div:
+      case Instruction::Rem:
+        // Logical Operations
+      case Instruction::And:
+      case Instruction::Or:
+      case Instruction::Xor:
+
+        // Binary Comparison Instructions
+      case Instruction::SetEQ:
+      case Instruction::SetNE:
+      case Instruction::SetLE:
+      case Instruction::SetGE:
+      case Instruction::SetLT:
+      case Instruction::SetGT:
+        NewI = BinaryOperator::create((Instruction::BinaryOps)I->getOpcode(),
+                                      ConvertValue(I->getOperand(0)),
+                                      ConvertValue(I->getOperand(1)));
+        break;
+
+      case Instruction::Shr:
+      case Instruction::Shl:
+        NewI = new ShiftInst(cast<ShiftInst>(I)->getOpcode(),
+                             ConvertValue(I->getOperand(0)),
+                             ConvertValue(I->getOperand(1)));
+        break;
+
+
+        // Memory Instructions
+      case Instruction::Alloca:
+        NewI = 
+          new AllocaInst(ConvertType(I->getType()),
+                         I->getNumOperands()?ConvertValue(I->getOperand(0)):0);
+        break;
+      case Instruction::Malloc:
+        NewI = 
+          new MallocInst(ConvertType(I->getType()),
+                         I->getNumOperands()?ConvertValue(I->getOperand(0)):0);
+        break;
+
+      case Instruction::Free:
+        NewI = new FreeInst(ConvertValue(I->getOperand(0)));
+        break;
+
+      case Instruction::Load:
+      case Instruction::Store:
+      case Instruction::GetElementPtr: {
+        const MemAccessInst *MAI = cast<MemAccessInst>(I);
+        vector<ConstPoolVal*> Indices = MAI->getIndices();
+        const Value *Ptr = MAI->getPointerOperand();
+        Value *NewPtr = ConvertValue(Ptr);
+        if (!Indices.empty()) {
+          const Type *PTy = cast<PointerType>(Ptr->getType())->getValueType();
+          AdjustIndices(cast<StructType>(PTy), Indices);
+        }
+
+        if (const LoadInst *LI = dyn_cast<LoadInst>(I)) {
+          NewI = new LoadInst(NewPtr, Indices);
+        } else if (const StoreInst *SI = dyn_cast<StoreInst>(I)) {
+          NewI = new StoreInst(ConvertValue(I->getOperand(0)), NewPtr, Indices);
+        } else if (const GetElementPtrInst *GEP =
+                   dyn_cast<GetElementPtrInst>(I)) {
+          NewI = new GetElementPtrInst(NewPtr, Indices);
+        } else {
+          assert(0 && "Unknown memory access inst!!!");
+        }
+        break;
+      }
+
+        // Miscellaneous Instructions
+      case Instruction::PHINode: {
+        const PHINode *OldPN = cast<PHINode>(I);
+        PHINode *PN = new PHINode(ConvertType(I->getType()));
+        for (unsigned i = 0; i < OldPN->getNumIncomingValues(); ++i)
+          PN->addIncoming(ConvertValue(OldPN->getIncomingValue(i)),
+                    cast<BasicBlock>(ConvertValue(OldPN->getIncomingBlock(i))));
+        NewI = PN;
+        break;
+      }
+      case Instruction::Cast:
+        NewI = new CastInst(ConvertValue(I->getOperand(0)),
+                            ConvertType(I->getType()));
+        break;
+      case Instruction::Call: {
+        Value *Meth = ConvertValue(I->getOperand(0));
+        vector<Value*> Operands;
+        for (unsigned i = 1; i < I->getNumOperands(); ++i)
+          Operands.push_back(ConvertValue(I->getOperand(i)));
+        NewI = new CallInst(Meth, Operands);
+        break;
+      }
+        
+      default:
+        assert(0 && "UNKNOWN INSTRUCTION ENCOUNTERED!\n");
+        break;
+      }
+
+      NewI->setName(I->getName());
+      NewBB->getInstList().push_back(NewI);
+
+      // Check to see if we had to make a placeholder for this value...
+      map<const Value*,Value*>::iterator LVMI = LocalValueMap.find(I);
+      if (LVMI != LocalValueMap.end()) {
+        // Yup, make sure it's a placeholder...
+        Instruction *I = cast<Instruction>(LVMI->second);
+        assert(I->getOpcode() == Instruction::UserOp1 && "Not a placeholder!");
+
+        // Replace all uses of the place holder with the real deal...
+        I->replaceAllUsesWith(NewI);
+        delete I;                    // And free the placeholder memory
+      }
+
+      // Keep track of the fact the the local implementation of this instruction
+      // is NewI.
+      LocalValueMap[I] = NewI;
+    }
+  }
+
+  LocalValueMap.clear();
+  return true;
+}