1 //===- MutateStructTypes.cpp - Change struct defns --------------------------=//
3 // This pass is used to change structure accesses and type definitions in some
4 // way. It can be used to arbitrarily permute structure fields, safely, without
5 // breaking code. A transformation may only be done on a type if that type has
6 // been found to be "safe" by the 'FindUnsafePointerTypes' pass. This pass will
7 // assert and die if you try to do an illegal transformation.
9 // This is an interprocedural pass that requires the entire program to do a
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Transforms/MutateStructTypes.h"
15 #include "llvm/DerivedTypes.h"
16 #include "llvm/Module.h"
17 #include "llvm/SymbolTable.h"
18 #include "llvm/Instructions.h"
19 #include "llvm/Constants.h"
20 #include "Support/STLExtras.h"
21 #include "Support/Debug.h"
24 // ValuePlaceHolder - A stupid little marker value. It appears as an
25 // instruction of type Instruction::UserOp1.
27 struct ValuePlaceHolder : public Instruction {
28 ValuePlaceHolder(const Type *Ty) : Instruction(Ty, UserOp1, "") {}
30 virtual Instruction *clone() const { abort(); return 0; }
31 virtual const char *getOpcodeName() const { return "placeholder"; }
35 // ConvertType - Convert from the old type system to the new one...
36 const Type *MutateStructTypes::ConvertType(const Type *Ty) {
37 if (Ty->isPrimitiveType() ||
38 isa<OpaqueType>(Ty)) return Ty; // Don't convert primitives
40 std::map<const Type *, PATypeHolder>::iterator I = TypeMap.find(Ty);
41 if (I != TypeMap.end()) return I->second;
43 const Type *DestTy = 0;
45 PATypeHolder PlaceHolder = OpaqueType::get();
46 TypeMap.insert(std::make_pair(Ty, PlaceHolder.get()));
48 switch (Ty->getPrimitiveID()) {
49 case Type::FunctionTyID: {
50 const FunctionType *MT = cast<FunctionType>(Ty);
51 const Type *RetTy = ConvertType(MT->getReturnType());
52 std::vector<const Type*> ArgTypes;
54 for (FunctionType::ParamTypes::const_iterator I = MT->getParamTypes().begin(),
55 E = MT->getParamTypes().end(); I != E; ++I)
56 ArgTypes.push_back(ConvertType(*I));
58 DestTy = FunctionType::get(RetTy, ArgTypes, MT->isVarArg());
61 case Type::StructTyID: {
62 const StructType *ST = cast<StructType>(Ty);
63 const StructType::ElementTypes &El = ST->getElementTypes();
64 std::vector<const Type *> Types;
66 for (StructType::ElementTypes::const_iterator I = El.begin(), E = El.end();
68 Types.push_back(ConvertType(*I));
69 DestTy = StructType::get(Types);
73 DestTy = ArrayType::get(ConvertType(cast<ArrayType>(Ty)->getElementType()),
74 cast<ArrayType>(Ty)->getNumElements());
77 case Type::PointerTyID:
78 DestTy = PointerType::get(
79 ConvertType(cast<PointerType>(Ty)->getElementType()));
82 assert(0 && "Unknown type!");
86 assert(DestTy && "Type didn't get created!?!?");
88 // Refine our little placeholder value into a real type...
89 ((DerivedType*)PlaceHolder.get())->refineAbstractTypeTo(DestTy);
90 TypeMap.insert(std::make_pair(Ty, PlaceHolder.get()));
92 return PlaceHolder.get();
96 // AdjustIndices - Convert the indexes specifed by Idx to the new changed form
97 // using the specified OldTy as the base type being indexed into.
99 void MutateStructTypes::AdjustIndices(const CompositeType *OldTy,
100 std::vector<Value*> &Idx,
102 assert(i < Idx.size() && "i out of range!");
103 const CompositeType *NewCT = cast<CompositeType>(ConvertType(OldTy));
104 if (NewCT == OldTy) return; // No adjustment unless type changes
106 if (const StructType *OldST = dyn_cast<StructType>(OldTy)) {
107 // Figure out what the current index is...
108 unsigned ElNum = cast<ConstantUInt>(Idx[i])->getValue();
109 assert(ElNum < OldST->getElementTypes().size());
111 std::map<const StructType*, TransformType>::iterator
112 I = Transforms.find(OldST);
113 if (I != Transforms.end()) {
114 assert(ElNum < I->second.second.size());
115 // Apply the XForm specified by Transforms map...
116 unsigned NewElNum = I->second.second[ElNum];
117 Idx[i] = ConstantUInt::get(Type::UByteTy, NewElNum);
121 // Recursively process subtypes...
122 if (i+1 < Idx.size())
123 AdjustIndices(cast<CompositeType>(OldTy->getTypeAtIndex(Idx[i])), Idx, i+1);
127 // ConvertValue - Convert from the old value in the old type system to the new
130 Value *MutateStructTypes::ConvertValue(const Value *V) {
131 // Ignore null values and simple constants..
132 if (V == 0) return 0;
134 if (const Constant *CPV = dyn_cast<Constant>(V)) {
135 if (V->getType()->isPrimitiveType())
138 if (isa<ConstantPointerNull>(CPV))
139 return ConstantPointerNull::get(
140 cast<PointerType>(ConvertType(V->getType())));
141 assert(0 && "Unable to convert constpool val of this type!");
144 // Check to see if this is an out of function reference first...
145 if (const GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
146 // Check to see if the value is in the map...
147 std::map<const GlobalValue*, GlobalValue*>::iterator I = GlobalMap.find(GV);
148 if (I == GlobalMap.end())
149 return (Value*)GV; // Not mapped, just return value itself
153 std::map<const Value*, Value*>::iterator I = LocalValueMap.find(V);
154 if (I != LocalValueMap.end()) return I->second;
156 if (const BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
157 // Create placeholder block to represent the basic block we haven't seen yet
158 // This will be used when the block gets created.
160 return LocalValueMap[V] = new BasicBlock(BB->getName());
163 DEBUG(std::cerr << "NPH: " << V << "\n");
165 // Otherwise make a constant to represent it
166 return LocalValueMap[V] = new ValuePlaceHolder(ConvertType(V->getType()));
170 // setTransforms - Take a map that specifies what transformation to do for each
171 // field of the specified structure types. There is one element of the vector
172 // for each field of the structure. The value specified indicates which slot of
173 // the destination structure the field should end up in. A negative value
174 // indicates that the field should be deleted entirely.
176 void MutateStructTypes::setTransforms(const TransformsType &XForm) {
178 // Loop over the types and insert dummy entries into the type map so that
179 // recursive types are resolved properly...
180 for (std::map<const StructType*, std::vector<int> >::const_iterator
181 I = XForm.begin(), E = XForm.end(); I != E; ++I) {
182 const StructType *OldTy = I->first;
183 TypeMap.insert(std::make_pair(OldTy, OpaqueType::get()));
186 // Loop over the type specified and figure out what types they should become
187 for (std::map<const StructType*, std::vector<int> >::const_iterator
188 I = XForm.begin(), E = XForm.end(); I != E; ++I) {
189 const StructType *OldTy = I->first;
190 const std::vector<int> &InVec = I->second;
192 assert(OldTy->getElementTypes().size() == InVec.size() &&
193 "Action not specified for every element of structure type!");
195 std::vector<const Type *> NewType;
197 // Convert the elements of the type over, including the new position mapping
199 std::vector<int>::const_iterator TI = find(InVec.begin(), InVec.end(), Idx);
200 while (TI != InVec.end()) {
201 unsigned Offset = TI-InVec.begin();
202 const Type *NewEl = ConvertType(OldTy->getContainedType(Offset));
203 assert(NewEl && "Element not found!");
204 NewType.push_back(NewEl);
206 TI = find(InVec.begin(), InVec.end(), ++Idx);
209 // Create a new type that corresponds to the destination type
210 PATypeHolder NSTy = StructType::get(NewType);
212 // Refine the old opaque type to the new type to properly handle recursive
215 const Type *OldTypeStub = TypeMap.find(OldTy)->second.get();
216 ((DerivedType*)OldTypeStub)->refineAbstractTypeTo(NSTy);
218 // Add the transformation to the Transforms map.
219 Transforms.insert(std::make_pair(OldTy,
220 std::make_pair(cast<StructType>(NSTy.get()), InVec)));
222 DEBUG(std::cerr << "Mutate " << OldTy << "\nTo " << NSTy << "\n");
226 void MutateStructTypes::clearTransforms() {
230 assert(LocalValueMap.empty() &&
231 "Local Value Map should always be empty between transformations!");
234 // processGlobals - This loops over global constants defined in the
235 // module, converting them to their new type.
237 void MutateStructTypes::processGlobals(Module &M) {
238 // Loop through the functions in the module and create a new version of the
239 // function to contained the transformed code. Also, be careful to not
240 // process the values that we add.
242 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
243 if (!I->isExternal()) {
244 const FunctionType *NewMTy =
245 cast<FunctionType>(ConvertType(I->getFunctionType()));
247 // Create a new function to put stuff into...
248 Function *NewMeth = new Function(NewMTy, I->getLinkage(), I->getName());
250 I->setName("OLD."+I->getName());
252 // Insert the new function into the function list... to be filled in later
253 M.getFunctionList().push_back(NewMeth);
255 // Keep track of the association...
256 GlobalMap[I] = NewMeth;
259 // TODO: HANDLE GLOBAL VARIABLES
261 // Remap the symbol table to refer to the types in a nice way
263 SymbolTable &ST = M.getSymbolTable();
264 SymbolTable::iterator I = ST.find(Type::TypeTy);
265 if (I != ST.end()) { // Get the type plane for Type's
266 SymbolTable::VarMap &Plane = I->second;
267 for (SymbolTable::type_iterator TI = Plane.begin(), TE = Plane.end();
269 // FIXME: This is gross, I'm reaching right into a symbol table and
270 // mucking around with it's internals... but oh well.
272 TI->second = (Value*)cast<Type>(ConvertType(cast<Type>(TI->second)));
278 // removeDeadGlobals - For this pass, all this does is remove the old versions
279 // of the functions and global variables that we no longer need.
280 void MutateStructTypes::removeDeadGlobals(Module &M) {
281 // Prepare for deletion of globals by dropping their interdependencies...
282 for(Module::iterator I = M.begin(); I != M.end(); ++I) {
283 if (GlobalMap.find(I) != GlobalMap.end())
284 I->dropAllReferences();
287 // Run through and delete the functions and global variables...
288 #if 0 // TODO: HANDLE GLOBAL VARIABLES
289 M->getGlobalList().delete_span(M.gbegin(), M.gbegin()+NumGVars/2);
291 for(Module::iterator I = M.begin(); I != M.end();) {
292 if (GlobalMap.find(I) != GlobalMap.end())
293 I = M.getFunctionList().erase(I);
301 // transformFunction - This transforms the instructions of the function to use
304 void MutateStructTypes::transformFunction(Function *m) {
305 const Function *M = m;
306 std::map<const GlobalValue*, GlobalValue*>::iterator GMI = GlobalMap.find(M);
307 if (GMI == GlobalMap.end())
308 return; // Do not affect one of our new functions that we are creating
310 Function *NewMeth = cast<Function>(GMI->second);
312 // Okay, first order of business, create the arguments...
313 for (Function::aiterator I = m->abegin(), E = m->aend(),
314 DI = NewMeth->abegin(); I != E; ++I, ++DI) {
315 DI->setName(I->getName());
316 LocalValueMap[I] = DI; // Keep track of value mapping
320 // Loop over all of the basic blocks copying instructions over...
321 for (Function::const_iterator BB = M->begin(), BBE = M->end(); BB != BBE;
323 // Create a new basic block and establish a mapping between the old and new
324 BasicBlock *NewBB = cast<BasicBlock>(ConvertValue(BB));
325 NewMeth->getBasicBlockList().push_back(NewBB); // Add block to function
327 // Copy over all of the instructions in the basic block...
328 for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
331 const Instruction &I = *II; // Get the current instruction...
332 Instruction *NewI = 0;
334 switch (I.getOpcode()) {
335 // Terminator Instructions
336 case Instruction::Ret:
337 NewI = new ReturnInst(
338 ConvertValue(cast<ReturnInst>(I).getReturnValue()));
340 case Instruction::Br: {
341 const BranchInst &BI = cast<BranchInst>(I);
342 if (BI.isConditional()) {
344 new BranchInst(cast<BasicBlock>(ConvertValue(BI.getSuccessor(0))),
345 cast<BasicBlock>(ConvertValue(BI.getSuccessor(1))),
346 ConvertValue(BI.getCondition()));
349 new BranchInst(cast<BasicBlock>(ConvertValue(BI.getSuccessor(0))));
353 case Instruction::Switch:
354 case Instruction::Invoke:
355 assert(0 && "Insn not implemented!");
357 // Binary Instructions
358 case Instruction::Add:
359 case Instruction::Sub:
360 case Instruction::Mul:
361 case Instruction::Div:
362 case Instruction::Rem:
363 // Logical Operations
364 case Instruction::And:
365 case Instruction::Or:
366 case Instruction::Xor:
368 // Binary Comparison Instructions
369 case Instruction::SetEQ:
370 case Instruction::SetNE:
371 case Instruction::SetLE:
372 case Instruction::SetGE:
373 case Instruction::SetLT:
374 case Instruction::SetGT:
375 NewI = BinaryOperator::create((Instruction::BinaryOps)I.getOpcode(),
376 ConvertValue(I.getOperand(0)),
377 ConvertValue(I.getOperand(1)));
380 case Instruction::Shr:
381 case Instruction::Shl:
382 NewI = new ShiftInst(cast<ShiftInst>(I).getOpcode(),
383 ConvertValue(I.getOperand(0)),
384 ConvertValue(I.getOperand(1)));
388 // Memory Instructions
389 case Instruction::Alloca:
392 ConvertType(cast<PointerType>(I.getType())->getElementType()),
393 I.getNumOperands() ? ConvertValue(I.getOperand(0)) :0);
395 case Instruction::Malloc:
398 ConvertType(cast<PointerType>(I.getType())->getElementType()),
399 I.getNumOperands() ? ConvertValue(I.getOperand(0)) :0);
402 case Instruction::Free:
403 NewI = new FreeInst(ConvertValue(I.getOperand(0)));
406 case Instruction::Load:
407 NewI = new LoadInst(ConvertValue(I.getOperand(0)));
409 case Instruction::Store:
410 NewI = new StoreInst(ConvertValue(I.getOperand(0)),
411 ConvertValue(I.getOperand(1)));
413 case Instruction::GetElementPtr: {
414 const GetElementPtrInst &GEP = cast<GetElementPtrInst>(I);
415 std::vector<Value*> Indices(GEP.idx_begin(), GEP.idx_end());
416 if (!Indices.empty()) {
418 cast<PointerType>(GEP.getOperand(0)->getType())->getElementType();
419 AdjustIndices(cast<CompositeType>(PTy), Indices);
422 NewI = new GetElementPtrInst(ConvertValue(GEP.getOperand(0)), Indices);
426 // Miscellaneous Instructions
427 case Instruction::PHINode: {
428 const PHINode &OldPN = cast<PHINode>(I);
429 PHINode *PN = new PHINode(ConvertType(OldPN.getType()));
430 for (unsigned i = 0; i < OldPN.getNumIncomingValues(); ++i)
431 PN->addIncoming(ConvertValue(OldPN.getIncomingValue(i)),
432 cast<BasicBlock>(ConvertValue(OldPN.getIncomingBlock(i))));
436 case Instruction::Cast:
437 NewI = new CastInst(ConvertValue(I.getOperand(0)),
438 ConvertType(I.getType()));
440 case Instruction::Call: {
441 Value *Meth = ConvertValue(I.getOperand(0));
442 std::vector<Value*> Operands;
443 for (unsigned i = 1; i < I.getNumOperands(); ++i)
444 Operands.push_back(ConvertValue(I.getOperand(i)));
445 NewI = new CallInst(Meth, Operands);
450 assert(0 && "UNKNOWN INSTRUCTION ENCOUNTERED!\n");
454 NewI->setName(I.getName());
455 NewBB->getInstList().push_back(NewI);
457 // Check to see if we had to make a placeholder for this value...
458 std::map<const Value*,Value*>::iterator LVMI = LocalValueMap.find(&I);
459 if (LVMI != LocalValueMap.end()) {
460 // Yup, make sure it's a placeholder...
461 Instruction *I = cast<Instruction>(LVMI->second);
462 assert(I->getOpcode() == Instruction::UserOp1 && "Not a placeholder!");
464 // Replace all uses of the place holder with the real deal...
465 I->replaceAllUsesWith(NewI);
466 delete I; // And free the placeholder memory
469 // Keep track of the fact the the local implementation of this instruction
471 LocalValueMap[&I] = NewI;
475 LocalValueMap.clear();
479 bool MutateStructTypes::run(Module &M) {
482 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
483 transformFunction(I);
485 removeDeadGlobals(M);