// ################################################### BRANCH MANIPULATION LOGIC ###################################################
// insert the given new target basic block (given by start and end block) between the given branch to manipulate
private void insertBasicBlockBetweenBranch(BasicBlock introBasicBlock, BasicBlock outroBasicBlock, IBranchTarget branchToManipulate, ref BasicBlock branchToManipulateTargetBasicBlock, BasicBlock newTargetStart, BasicBlock newTargetEnd, IBranchTarget exitBranch, ref BasicBlock exitBranchTargetBasicBlock) {
// check if there exists try/handler blocks
if (introBasicBlock.tryBlocks.Count() != 0) {
throw new ArgumentException("Try blocks not yet implemented.");
}
if (introBasicBlock.handlerBlocks.Count() != 0) {
throw new ArgumentException("Handler blocks not yet implemented.");
}
// add the new target given by basic blocks to the method cfg basic blocks
if (!methodCfg.basicBlocks.Contains(newTargetStart)) {
this.methodCfg.basicBlocks.Add(newTargetStart);
}
// recursively add all other basic blocks of the new target code to the method cfg
if (newTargetStart.exitBranch as NoBranchTarget != null) {
if (newTargetStart != newTargetEnd) {
BasicBlock tempBB = ((NoBranchTarget)newTargetStart.exitBranch).takenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
}
else if (newTargetStart.exitBranch as TryBlockTarget != null) {
if (newTargetStart != newTargetEnd) {
BasicBlock tempBB = ((TryBlockTarget)newTargetStart.exitBranch).takenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
}
else if (newTargetStart.exitBranch as UnconditionalBranchTarget != null) {
if (newTargetStart != newTargetEnd) {
BasicBlock tempBB = ((UnconditionalBranchTarget)newTargetStart.exitBranch).takenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
}
else if (newTargetStart.exitBranch as ConditionalBranchTarget != null) {
BasicBlock tempBB = ((ConditionalBranchTarget)newTargetStart.exitBranch).takenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
tempBB = ((ConditionalBranchTarget)newTargetStart.exitBranch).notTakenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
else if (newTargetStart.exitBranch as SwitchBranchTarget != null) {
BasicBlock tempBB = ((SwitchBranchTarget)newTargetStart.exitBranch).notTakenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
foreach (BasicBlock takenTempBB in ((SwitchBranchTarget)newTargetStart.exitBranch).takenTarget) {
this.addBasicBlockToCfgRecursively(takenTempBB);
}
}
else if (newTargetStart.exitBranch as ExceptionBranchTarget != null) {
BasicBlock tempBB = ((ExceptionBranchTarget)newTargetStart.exitBranch).exceptionTarget;
this.addBasicBlockToCfgRecursively(tempBB);
tempBB = ((ExceptionBranchTarget)newTargetStart.exitBranch).exitTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
else {
throw new ArgumentException("Do not know how to handle branch target in order to add all basic blocks to the method CFG.");
}
// add the branch to manipulate as the entry branch of the new target basic block
newTargetStart.entryBranches.Add(branchToManipulate);
// remove branch entry from old target
outroBasicBlock.entryBranches.Remove(branchToManipulate);
// make the given target basic block the new branch target
branchToManipulateTargetBasicBlock = newTargetStart;
// set branch as exit branch of the new last basic block of the new target code
newTargetEnd.exitBranch = exitBranch;
// set the last basic block of the new target as source of the exit branch
exitBranch.sourceBasicBlock = newTargetEnd;
exitBranchTargetBasicBlock = outroBasicBlock;
// add branch to the list of entry branches of the original outro basic block
// (if the exit branch of the new code is a no branch target => check if it is the only one that entries the outro basic block)
if ((exitBranch as NoBranchTarget) != null) {
foreach (IBranchTarget temp in outroBasicBlock.entryBranches) {
if ((temp as NoBranchTarget) != null) {
throw new ArgumentException("Only one 'No Branch Target' can be entry of a basic block.");
}
}
}
outroBasicBlock.entryBranches.Add(exitBranch);
}
// this function replaces a basic block inside the cfg (oldBasicBlock) with a construction of new basic blocks (newBasicBlockStart and newBasicBlockEnd)
public void replaceBasicBlock(BasicBlock oldBasicBlock, BasicBlock newBasicBlockStart, BasicBlock newBasicBlockEnd)
{
// add new basic blocks to cfg
this.addBasicBlockToCfgRecursively(newBasicBlockStart);
// add entry branches that enter the old basic block to the new basic block
newBasicBlockStart.entryBranches.AddRange(oldBasicBlock.entryBranches);
// exchange the target of the entry branches from the old basic block to the new one
foreach (IBranchTarget entryBranch in new List <IBranchTarget>(oldBasicBlock.entryBranches))
{
if ((entryBranch as NoBranchTarget) != null)
{
NoBranchTarget tempEntryBranch = (entryBranch as NoBranchTarget);
// check sanity of entry branch
if (tempEntryBranch.takenTarget != oldBasicBlock)
{
throw new ArgumentException("Entry branch must have old basic block as target.");
}
// set new basic block as target
tempEntryBranch.takenTarget = newBasicBlockStart;
}
else if ((entryBranch as UnconditionalBranchTarget) != null)
{
UnconditionalBranchTarget tempEntryBranch = (entryBranch as UnconditionalBranchTarget);
// check sanity of entry branch
if (tempEntryBranch.takenTarget != oldBasicBlock)
{
throw new ArgumentException("Entry branch must have old basic block as target.");
}
// set new basic block as target
tempEntryBranch.takenTarget = newBasicBlockStart;
}
else if ((entryBranch as ConditionalBranchTarget) != null)
{
ConditionalBranchTarget tempEntryBranch = (entryBranch as ConditionalBranchTarget);
bool sanity = false;
// change all branches to the old basic block to the new basic block
if (tempEntryBranch.takenTarget == oldBasicBlock)
{
tempEntryBranch.takenTarget = newBasicBlockStart;
sanity = true;
}
if (tempEntryBranch.notTakenTarget == oldBasicBlock)
{
tempEntryBranch.notTakenTarget = newBasicBlockStart;
sanity = true;
}
// check sanity of entry branch
if (!sanity)
{
throw new ArgumentException("Entry branch must have old basic block as target.");
}
}
else if ((entryBranch as SwitchBranchTarget) != null)
{
SwitchBranchTarget tempEntryBranch = (entryBranch as SwitchBranchTarget);
bool sanity = false;
// change all branches to the old basic block to the new basic block
if (tempEntryBranch.notTakenTarget == oldBasicBlock)
{
tempEntryBranch.notTakenTarget = newBasicBlockStart;
sanity = true;
}
for (int idx = 0; idx < tempEntryBranch.takenTarget.Count(); idx++)
{
if (tempEntryBranch.takenTarget.ElementAt(idx) == oldBasicBlock)
{
tempEntryBranch.takenTarget[idx] = newBasicBlockStart;
sanity = true;
}
}
// check sanity of entry branch
if (!sanity)
{
throw new ArgumentException("Entry branch must have old basic block as target.");
}
}
else
{
throw new ArgumentException("Not yet implemented.");
}
// remove entry branch from the old basic block entry branches list
oldBasicBlock.entryBranches.Remove(entryBranch);
}
IBranchTarget exitBranch = oldBasicBlock.exitBranch;
// change the exit branch of the old basic block to be the exit branch of the new one
exitBranch.sourceBasicBlock = newBasicBlockEnd;
newBasicBlockEnd.exitBranch = exitBranch;
// check if the old basic block was the start basic block of the cfg
// => change it to the new basic block
if (this.methodCfg.startBasicBlock == oldBasicBlock)
{
this.methodCfg.startBasicBlock = newBasicBlockStart;
}
// remove old basic block if it still belongs to the cfg
if (this.methodCfg.basicBlocks.Contains(oldBasicBlock))
{
this.methodCfg.basicBlocks.Remove(oldBasicBlock);
}
}
// ################################################### BRANCH MANIPULATION LOGIC ###################################################
// insert the given new target basic block (given by start and end block) between the given branch to manipulate
private void insertBasicBlockBetweenBranch(BasicBlock introBasicBlock, BasicBlock outroBasicBlock, IBranchTarget branchToManipulate, ref BasicBlock branchToManipulateTargetBasicBlock, BasicBlock newTargetStart, BasicBlock newTargetEnd, IBranchTarget exitBranch, ref BasicBlock exitBranchTargetBasicBlock)
{
// check if there exists try/handler blocks
if (introBasicBlock.tryBlocks.Count() != 0)
{
throw new ArgumentException("Try blocks not yet implemented.");
}
if (introBasicBlock.handlerBlocks.Count() != 0)
{
throw new ArgumentException("Handler blocks not yet implemented.");
}
// add the new target given by basic blocks to the method cfg basic blocks
if (!methodCfg.basicBlocks.Contains(newTargetStart))
{
this.methodCfg.basicBlocks.Add(newTargetStart);
}
// recursively add all other basic blocks of the new target code to the method cfg
if (newTargetStart.exitBranch as NoBranchTarget != null)
{
if (newTargetStart != newTargetEnd)
{
BasicBlock tempBB = ((NoBranchTarget)newTargetStart.exitBranch).takenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
}
else if (newTargetStart.exitBranch as TryBlockTarget != null)
{
if (newTargetStart != newTargetEnd)
{
BasicBlock tempBB = ((TryBlockTarget)newTargetStart.exitBranch).takenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
}
else if (newTargetStart.exitBranch as UnconditionalBranchTarget != null)
{
if (newTargetStart != newTargetEnd)
{
BasicBlock tempBB = ((UnconditionalBranchTarget)newTargetStart.exitBranch).takenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
}
else if (newTargetStart.exitBranch as ConditionalBranchTarget != null)
{
BasicBlock tempBB = ((ConditionalBranchTarget)newTargetStart.exitBranch).takenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
tempBB = ((ConditionalBranchTarget)newTargetStart.exitBranch).notTakenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
else if (newTargetStart.exitBranch as SwitchBranchTarget != null)
{
BasicBlock tempBB = ((SwitchBranchTarget)newTargetStart.exitBranch).notTakenTarget;
this.addBasicBlockToCfgRecursively(tempBB);
foreach (BasicBlock takenTempBB in ((SwitchBranchTarget)newTargetStart.exitBranch).takenTarget)
{
this.addBasicBlockToCfgRecursively(takenTempBB);
}
}
else if (newTargetStart.exitBranch as ExceptionBranchTarget != null)
{
BasicBlock tempBB = ((ExceptionBranchTarget)newTargetStart.exitBranch).exceptionTarget;
this.addBasicBlockToCfgRecursively(tempBB);
tempBB = ((ExceptionBranchTarget)newTargetStart.exitBranch).exitTarget;
this.addBasicBlockToCfgRecursively(tempBB);
}
else
{
throw new ArgumentException("Do not know how to handle branch target in order to add all basic blocks to the method CFG.");
}
// add the branch to manipulate as the entry branch of the new target basic block
newTargetStart.entryBranches.Add(branchToManipulate);
// remove branch entry from old target
outroBasicBlock.entryBranches.Remove(branchToManipulate);
// make the given target basic block the new branch target
branchToManipulateTargetBasicBlock = newTargetStart;
// set branch as exit branch of the new last basic block of the new target code
newTargetEnd.exitBranch = exitBranch;
// set the last basic block of the new target as source of the exit branch
exitBranch.sourceBasicBlock = newTargetEnd;
exitBranchTargetBasicBlock = outroBasicBlock;
// add branch to the list of entry branches of the original outro basic block
// (if the exit branch of the new code is a no branch target => check if it is the only one that entries the outro basic block)
if ((exitBranch as NoBranchTarget) != null)
{
foreach (IBranchTarget temp in outroBasicBlock.entryBranches)
{
if ((temp as NoBranchTarget) != null)
{
throw new ArgumentException("Only one 'No Branch Target' can be entry of a basic block.");
}
}
}
outroBasicBlock.entryBranches.Add(exitBranch);
}
// build recursively the cfg of the given operations
private void buildRecursivelyCfg(MethodCfg methodCfg, IEnumerable<IOperation> operations, int currentIdx, IBranchTarget entryBranch, ref BasicBlock currentBasicBlock) {
// check if a new basic block has to be created
for (int bbIdx = 0; bbIdx < methodCfg.basicBlocks.Count(); bbIdx++) {
// check if the current index points into an existing basic block
// => split basic block
BasicBlock tempBB = methodCfg.basicBlocks.ElementAt(bbIdx);
if (tempBB.startIdx < currentIdx && tempBB.endIdx >= currentIdx) {
// create new basic block which will be the second half of the found one
BasicBlock newBasicBlock = new BasicBlock(this.semanticId);
this.semanticId++;
newBasicBlock.startIdx = currentIdx;
newBasicBlock.endIdx = tempBB.endIdx;
tempBB.endIdx = currentIdx - 1;
// move the exit basic blocks to the new created basic block
// and make the new created basic block the exit of the splitted one
newBasicBlock.exitBranch = tempBB.exitBranch;
newBasicBlock.exitBranch.sourceBasicBlock = newBasicBlock;
NoBranchTarget tempExitBranch = new NoBranchTarget();
tempExitBranch.takenTarget = newBasicBlock;
tempExitBranch.sourceBasicBlock = tempBB;
tempBB.exitBranch = tempExitBranch;
// set the current basic block to the new created basic block
currentBasicBlock = newBasicBlock;
// add splitted basic block branch and basic block branch that leads to this split
// to the entries of the new one
newBasicBlock.entryBranches.Add(entryBranch);
newBasicBlock.entryBranches.Add(tempExitBranch);
// distribute the instructions to the basic blocks
List<IOperation> previousOperations = new List<IOperation>();
List<IOperation> nextOperations = new List<IOperation>();
for (int operationIdx = 0; (operationIdx + tempBB.startIdx) <= newBasicBlock.endIdx; operationIdx++) {
if ((operationIdx + tempBB.startIdx) < currentIdx) {
previousOperations.Add(tempBB.operations.ElementAt(operationIdx));
}
else {
nextOperations.Add(tempBB.operations.ElementAt(operationIdx));
}
}
tempBB.operations = previousOperations;
newBasicBlock.operations = nextOperations;
// add new basic block to the cfg
methodCfg.basicBlocks.Add(newBasicBlock);
return;
}
// if the current index of the operation points to the start index of an existing basic block
// => update entry branches
else if (tempBB.startIdx == currentIdx && entryBranch != null && currentBasicBlock != null) {
tempBB.entryBranches.Add(entryBranch);
// set the found basic block as the current basic block
currentBasicBlock = tempBB;
return;
}
// if the current index of the operation points to the start index of an existing basic block, has no entry branch
// and is not the first instruction
// set the current basic block to the found one
else if (currentIdx != 0 && tempBB.startIdx == currentIdx && currentBasicBlock != null) {
// set the found basic block as the current basic block
currentBasicBlock = tempBB;
return;
}
}
// set index of current basic block and add it to the cfg
currentBasicBlock.startIdx = currentIdx;
methodCfg.basicBlocks.Add(currentBasicBlock);
// check if the basic block was jumped to from another basic block
// => update entry branches
if (entryBranch != null) {
currentBasicBlock.entryBranches.Add(entryBranch);
}
// parse every instruction to find branches etc
for (int idx = currentIdx; idx < operations.Count(); idx++) {
// check if the current instruction is the start instruction of an already existing basic block (except the current basic block)
// => add the current basic block to the list of entry basic blocks, the found basic block to the list of exit basic blocks and set the index
for (int bbIdx = 0; bbIdx < methodCfg.basicBlocks.Count(); bbIdx++) {
BasicBlock tempBB = methodCfg.basicBlocks.ElementAt(bbIdx);
if (tempBB.startIdx == idx && tempBB != currentBasicBlock) {
currentBasicBlock.endIdx = idx - 1;
// create new exit branch and add it
NoBranchTarget currentExitBranch = new NoBranchTarget();
currentExitBranch.sourceBasicBlock = currentBasicBlock;
currentExitBranch.takenTarget = tempBB;
currentBasicBlock.exitBranch = currentExitBranch;
// add current exit branch as entry for the found one
tempBB.entryBranches.Add(currentExitBranch);
return;
}
}
// add current instruction to the basic block
var operation = operations.ElementAt(idx);
currentBasicBlock.operations.Add(operation);
// check for special instructions like branches
switch (operation.OperationCode) {
// conditional branch instructions
case OperationCode.Beq:
case OperationCode.Bge:
case OperationCode.Bge_Un:
case OperationCode.Bgt:
case OperationCode.Bgt_Un:
case OperationCode.Ble:
case OperationCode.Ble_Un:
case OperationCode.Blt:
case OperationCode.Blt_Un:
case OperationCode.Bne_Un:
case OperationCode.Brfalse:
case OperationCode.Brtrue:
case OperationCode.Beq_S:
case OperationCode.Bge_S:
case OperationCode.Bge_Un_S:
case OperationCode.Bgt_S:
case OperationCode.Bgt_Un_S:
case OperationCode.Ble_S:
case OperationCode.Ble_Un_S:
case OperationCode.Blt_S:
case OperationCode.Blt_Un_S:
case OperationCode.Bne_Un_S:
case OperationCode.Brfalse_S:
case OperationCode.Brtrue_S: {
// the current basic block ends here
currentBasicBlock.endIdx = idx;
// calculate the target index of the branch
int branchTargetIdx = 0;
uint branchTargetOffset;
// do operation value can be of type long which can not be casted in this way
if (operation.Value is long) {
branchTargetOffset = Convert.ToUInt32(operation.Value);
}
else {
branchTargetOffset = (uint)operation.Value;
}
while (true) {
if (operations.ElementAt(branchTargetIdx).Offset == branchTargetOffset) {
break;
}
else if (operations.ElementAt(branchTargetIdx).Offset > branchTargetOffset) {
throw new ArgumentException("Could not find target off branch.");
}
branchTargetIdx++;
}
// create new exit branch object
ConditionalBranchTarget currentExitBranch = new ConditionalBranchTarget();
currentExitBranch.sourceBasicBlock = currentBasicBlock;
currentExitBranch.notTakenTarget = new BasicBlock(this.semanticId);
this.semanticId++;
currentExitBranch.takenTarget = new BasicBlock(this.semanticId);
this.semanticId++;
currentBasicBlock.exitBranch = currentExitBranch;
// start two new basic blocks from this branch on and end current execution
this.buildRecursivelyCfg(methodCfg, operations, idx + 1, currentExitBranch, ref currentExitBranch.notTakenTarget);
this.buildRecursivelyCfg(methodCfg, operations, branchTargetIdx, currentExitBranch, ref currentExitBranch.takenTarget);
return;
}
// unconditional branch instructions
case OperationCode.Br:
case OperationCode.Br_S: {
// the current basic block ends here
currentBasicBlock.endIdx = idx;
// calculate the target index of the branch
int branchTargetIdx = 0;
uint branchTargetOffset = (uint)operation.Value;
while (true) {
if (operations.ElementAt(branchTargetIdx).Offset == branchTargetOffset) {
break;
}
else if (operations.ElementAt(branchTargetIdx).Offset > branchTargetOffset) {
throw new ArgumentException("Could not find target off branch.");
}
branchTargetIdx++;
}
// create new exit branch object
UnconditionalBranchTarget currentExitBranch = new UnconditionalBranchTarget();
currentExitBranch.sourceBasicBlock = currentBasicBlock;
currentExitBranch.takenTarget = new BasicBlock(this.semanticId);
this.semanticId++;
currentBasicBlock.exitBranch = currentExitBranch;
// start one new basic block from this branch on and end current execution
this.buildRecursivelyCfg(methodCfg, operations, branchTargetIdx, currentExitBranch, ref currentExitBranch.takenTarget);
return;
}
// exit operation
case OperationCode.Ret: {
// the current basic block ends here
currentBasicBlock.endIdx = idx;
// create new exit branch object
ExitBranchTarget currentExitBranch = new ExitBranchTarget();
currentExitBranch.sourceBasicBlock = currentBasicBlock;
currentBasicBlock.exitBranch = currentExitBranch;
// end current execution
return;
}
// operations that exit the current function/control flow
case OperationCode.Throw: {
// the current basic block ends here
currentBasicBlock.endIdx = idx;
// create new exit branch object
ThrowBranchTarget currentExitBranch = new ThrowBranchTarget();
currentExitBranch.sourceBasicBlock = currentBasicBlock;
currentBasicBlock.exitBranch = currentExitBranch;
// start a new basic block if this was not the last instruction of the method
// (needed because some control flows that are reached via throw are not found without it)
if ((idx + 1) < operations.Count()) {
BasicBlock newStartBasicBlock = new BasicBlock(this.semanticId);
this.semanticId++;
this.buildRecursivelyCfg(methodCfg, operations, idx + 1, null, ref newStartBasicBlock);
}
// end current execution
return;
}
// switch instruction (has a variable set of jump targets)
case OperationCode.Switch: {
// the current basic block ends here
currentBasicBlock.endIdx = idx;
// create new exit branch object
SwitchBranchTarget currentExitBranch = new SwitchBranchTarget();
currentExitBranch.sourceBasicBlock = currentBasicBlock;
currentExitBranch.notTakenTarget = new BasicBlock(this.semanticId);
this.semanticId++;
currentBasicBlock.exitBranch = currentExitBranch;
// calculate the target index of all switch branches
int counter = 0;
foreach (uint branchTargetOffset in (uint[])operation.Value) {
int branchTargetIdx = 0;
while (true) {
if (operations.ElementAt(branchTargetIdx).Offset == branchTargetOffset) {
break;
}
else if (operations.ElementAt(branchTargetIdx).Offset > branchTargetOffset) {
throw new ArgumentException("Could not find target off branch.");
}
branchTargetIdx++;
}
// start a new basic block from this branch on
BasicBlock tempNextBasicBlock = new BasicBlock(this.semanticId);
this.semanticId++;
this.buildRecursivelyCfg(methodCfg, operations, branchTargetIdx, currentExitBranch, ref tempNextBasicBlock);
// add new basic block to branch targets
currentExitBranch.takenTarget.Add(tempNextBasicBlock);
counter++;
}
// start a new basic block directly after the switch instruction and end current execution
this.buildRecursivelyCfg(methodCfg, operations, idx + 1, currentExitBranch, ref currentExitBranch.notTakenTarget);
return;
}
// exception handler beginning or end (end of try block or catch block)
case OperationCode.Leave:
case OperationCode.Leave_S: {
// the current basic block ends here
currentBasicBlock.endIdx = idx;
// calculate the target index of the branch
int branchTargetIdx = 0;
uint branchTargetOffset = (uint)operation.Value;
while (true) {
if (operations.ElementAt(branchTargetIdx).Offset == branchTargetOffset) {
break;
}
else if (operations.ElementAt(branchTargetIdx).Offset > branchTargetOffset) {
throw new ArgumentException("Could not find target off branch.");
}
branchTargetIdx++;
}
// create new exit branch object
ExceptionBranchTarget currentExitBranch = new ExceptionBranchTarget();
currentExitBranch.sourceBasicBlock = currentBasicBlock;
currentExitBranch.exceptionTarget = new BasicBlock(this.semanticId);
this.semanticId++;
currentExitBranch.exitTarget = new BasicBlock(this.semanticId);
this.semanticId++;
currentBasicBlock.exitBranch = currentExitBranch;
// start two new basic blocks from this branch on and end current execution
this.buildRecursivelyCfg(methodCfg, operations, idx + 1, currentExitBranch, ref currentExitBranch.exceptionTarget);
this.buildRecursivelyCfg(methodCfg, operations, branchTargetIdx, currentExitBranch, ref currentExitBranch.exitTarget);
return;
}
// create a virtual basic block at the end of a catch/finally handler
case OperationCode.Rethrow:
case OperationCode.Endfinally: {
// the current basic block ends here
currentBasicBlock.endIdx = idx;
// create new exit branch object
NoBranchTarget currentExitBranch = new NoBranchTarget();
currentExitBranch.sourceBasicBlock = currentBasicBlock;
currentExitBranch.takenTarget = new BasicBlock(this.semanticId);
this.semanticId++;
currentBasicBlock.exitBranch = currentExitBranch;
// start a new basic block from this branch on and end current execution
this.buildRecursivelyCfg(methodCfg, operations, idx + 1, currentExitBranch, ref currentExitBranch.takenTarget);
return;
}
default:
break;
}
}
}
// this function generates and injects code into the given entry branch that moves the pointer from the source node to the target node
private void injectLinkMoveCode(CfgManipulator cfgManipulator, BasicBlockGraphNodeLink startGraphLink, BasicBlockGraphNodeLink targetGraphLink, IBranchTarget entryBranch, int currentValidPathId, LocalDefinition currentNodeLocal) {
NodeObject targetNode = targetGraphLink.graphNode;
NodeObject startNode = startGraphLink.graphNode;
IBranchTarget branchToManipulate = entryBranch;
// do nothing if the source node is already the same as the target node
if (startNode == targetNode) {
return;
}
// check if the pointer have to be moved to the start pointer before it can be moved to the target element
bool goToStart = false;
if (startNode.positionInGraph.Count() >= targetNode.positionInGraph.Count()) {
goToStart = true;
}
else {
for (int idx = 0; idx < startNode.positionInGraph.Count(); idx++) {
if (startNode.positionInGraph.ElementAt(idx) != targetNode.positionInGraph.ElementAt(idx)) {
goToStart = true;
break;
}
}
}
// set current graph link (is used for the metadata of the pointer correcting basic blocks
BasicBlockGraphNodeLink currentGraphLink = new BasicBlockGraphNodeLink(startGraphLink.graphNode, currentValidPathId);
// check how to move the pointer to the target element
// => first go to the start pointer
if (goToStart) {
// generate and inject code that moves the pointer on a random path forward until the start node of the graph is reached
while (startNode != this.graph.startingNode) {
// generate code to move the pointer to the next node in the graph and inject it
int nextNodeIdx = this.prng.Next(this.graphDimension);
UnconditionalBranchTarget injectedExitBranch = new UnconditionalBranchTarget();
BasicBlock injectedBasicBlock = this.createCodeNextNode(injectedExitBranch, currentGraphLink, currentNodeLocal, nextNodeIdx, true);
if ((branchToManipulate as UnconditionalBranchTarget) != null) {
UnconditionalBranchTarget tempBranchToManipulate = (branchToManipulate as UnconditionalBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempBranchToManipulate, injectedBasicBlock, injectedExitBranch);
}
else if ((branchToManipulate as SwitchBranchTarget) != null) {
SwitchBranchTarget tempBranchToManipulate = (branchToManipulate as SwitchBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempBranchToManipulate, currentValidPathId, injectedBasicBlock, injectedExitBranch);
}
else {
throw new ArgumentException("Not yet implemented."); // TODO
}
// set the next branch to manipulate as the newly created exit branch
branchToManipulate = injectedExitBranch;
// move pointer to the next node in the graph or to the start node if it does not exist
if (startNode.nodeObjects[nextNodeIdx] == null) {
startNode = this.graph.startingNode;
}
else {
startNode = startNode.nodeObjects[nextNodeIdx];
}
// create new graph link for the current node
currentGraphLink = new BasicBlockGraphNodeLink(startNode, currentValidPathId);
}
// generate and inject code that moves the pointer to the correct position of the given graph node
foreach (int nextNodeIdx in targetNode.positionInGraph) {
// generate code to move the pointer to the next node in the graph and inject it
UnconditionalBranchTarget injectedExitBranch = new UnconditionalBranchTarget();
BasicBlock injectedBasicBlock = this.createCodeNextNode(injectedExitBranch, currentGraphLink, currentNodeLocal, nextNodeIdx, true);
if ((branchToManipulate as UnconditionalBranchTarget) != null) {
UnconditionalBranchTarget tempBranchToManipulate = (branchToManipulate as UnconditionalBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempBranchToManipulate, injectedBasicBlock, injectedExitBranch);
}
else if ((branchToManipulate as SwitchBranchTarget) != null) {
SwitchBranchTarget tempBranchToManipulate = (branchToManipulate as SwitchBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempBranchToManipulate, currentValidPathId, injectedBasicBlock, injectedExitBranch);
}
else {
throw new ArgumentException("Not yet implemented."); // TODO
}
// set the next branch to manipulate as the newly created exit branch
branchToManipulate = injectedExitBranch;
// move pointer to the next node in the graph or to the start node if it does not exist
if (startNode.nodeObjects[nextNodeIdx] == null) {
startNode = this.graph.startingNode;
}
else {
startNode = startNode.nodeObjects[nextNodeIdx];
}
// create new graph link for the current node
currentGraphLink = new BasicBlockGraphNodeLink(startNode, currentValidPathId);
}
}
// => go on a direct path to the target element
else {
// generate and inject code that moves the pointer to the correct position of the given graph node
for (int idx = startNode.positionInGraph.Count(); idx < targetNode.positionInGraph.Count(); idx++) {
// generate code to move the pointer to the next node in the graph and inject it
UnconditionalBranchTarget injectedExitBranch = new UnconditionalBranchTarget();
BasicBlock injectedBasicBlock = this.createCodeNextNode(injectedExitBranch, currentGraphLink, currentNodeLocal, targetNode.positionInGraph.ElementAt(idx), true);
if ((branchToManipulate as UnconditionalBranchTarget) != null) {
UnconditionalBranchTarget tempBranchToManipulate = (branchToManipulate as UnconditionalBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempBranchToManipulate, injectedBasicBlock, injectedExitBranch);
}
else if ((branchToManipulate as SwitchBranchTarget) != null) {
SwitchBranchTarget tempBranchToManipulate = (branchToManipulate as SwitchBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempBranchToManipulate, currentValidPathId, injectedBasicBlock, injectedExitBranch);
}
else {
throw new ArgumentException("Not yet implemented."); // TODO
}
// set the next branch to manipulate as the newly created exit branch
branchToManipulate = injectedExitBranch;
// move pointer to the next node in the graph or to the start node if it does not exist
if (startNode.nodeObjects[targetNode.positionInGraph.ElementAt(idx)] == null) {
startNode = this.graph.startingNode;
}
else {
startNode = startNode.nodeObjects[targetNode.positionInGraph.ElementAt(idx)];
}
// create new graph link for the current node
currentGraphLink = new BasicBlockGraphNodeLink(startNode, currentValidPathId);
}
}
// check if the final reached node is the same as the target node
if (startNode != targetNode) {
throw new ArgumentException("Current node and target node are not the same.");
}
}
// this function injects an opaque predicate to the target branch
private void injectOpaquePredicateCode(CfgManipulator cfgManipulator, MethodCfg methodCfg, BasicBlock targetBasicBlock, IBranchTarget targetBranch, BasicBlockGraphNodeLink link, int opaquePredicate, LocalDefinition currentNodeLocal) {
int currentValidPathId = link.validPathId;
ConditionalBranchTarget opaqueExitBranch = null;
// create "true" or "false" opaque predicate and add it to the code
switch (opaquePredicate) {
// "true" opaque predicate
case 0: {
BasicBlock opaqueStartBasicBlock = null;
this.createCodeTruePredicate(ref opaqueStartBasicBlock, ref opaqueExitBranch, link, currentNodeLocal);
// inject target branch with opaque predicate
if ((targetBranch as SwitchBranchTarget) != null) {
SwitchBranchTarget tempTargetBranch = (targetBranch as SwitchBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempTargetBranch, currentValidPathId, opaqueStartBasicBlock, opaqueExitBranch, true);
}
else if ((targetBranch as UnconditionalBranchTarget) != null) {
UnconditionalBranchTarget tempTargetBranch = (targetBranch as UnconditionalBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempTargetBranch, opaqueStartBasicBlock, opaqueExitBranch, true);
}
else {
throw new ArgumentException("Not implemented yet.");
}
// set template semantic id of dead code basic block
BasicBlock deadCodeBasicBlock = opaqueExitBranch.notTakenTarget;
GraphTransformerDeadCodeBasicBlock deadCodeMetadata = (deadCodeBasicBlock.transformationMetadata.ElementAt(0) as GraphTransformerDeadCodeBasicBlock);
deadCodeMetadata.semanticId = targetBasicBlock.semanticId;
// create intermediate basic block and inject it between correct opaque predicate branch and target basic block
BasicBlock intermediateBasicBlock = new BasicBlock();
intermediateBasicBlock.operations.Add(this.helperClass.createNewOperation(OperationCode.Br, 0));
methodCfg.basicBlocks.Add(intermediateBasicBlock);
// add metadata to intermediate basic block
GraphTransformerIntermediateBasicBlock metadataIntermediate = new GraphTransformerIntermediateBasicBlock();
metadataIntermediate.correspondingGraphNodes.Add(link);
intermediateBasicBlock.transformationMetadata.Add(metadataIntermediate);
// create intermediate exit branch
UnconditionalBranchTarget intermediateBasicBlockExitBranch = new UnconditionalBranchTarget();
intermediateBasicBlockExitBranch.sourceBasicBlock = intermediateBasicBlock;
intermediateBasicBlock.exitBranch = intermediateBasicBlockExitBranch;
cfgManipulator.insertBasicBlockBetweenBranch(opaqueExitBranch, true, intermediateBasicBlock, intermediateBasicBlockExitBranch);
break;
}
// "false" opaque predicate
case 1: {
BasicBlock opaqueStartBasicBlock = null;
this.createCodeFalsePredicate(ref opaqueStartBasicBlock, ref opaqueExitBranch, link, currentNodeLocal);
// inject target branch with opaque predicate
if ((targetBranch as SwitchBranchTarget) != null) {
SwitchBranchTarget tempTargetBranch = (targetBranch as SwitchBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempTargetBranch, currentValidPathId, opaqueStartBasicBlock, opaqueExitBranch, false);
}
else if ((targetBranch as UnconditionalBranchTarget) != null) {
UnconditionalBranchTarget tempTargetBranch = (targetBranch as UnconditionalBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempTargetBranch, opaqueStartBasicBlock, opaqueExitBranch, false);
}
else {
throw new ArgumentException("Not implemented yet.");
}
// set template semantic id of dead code basic block
BasicBlock deadCodeBasicBlock = opaqueExitBranch.takenTarget;
GraphTransformerDeadCodeBasicBlock deadCodeMetadata = (deadCodeBasicBlock.transformationMetadata.ElementAt(0) as GraphTransformerDeadCodeBasicBlock);
deadCodeMetadata.semanticId = targetBasicBlock.semanticId;
// create intermediate basic block and inject it between correct opaque predicate branch and target basic block
BasicBlock intermediateBasicBlock = new BasicBlock();
intermediateBasicBlock.operations.Add(this.helperClass.createNewOperation(OperationCode.Br, 0));
methodCfg.basicBlocks.Add(intermediateBasicBlock);
// add metadata to intermediate basic block
GraphTransformerIntermediateBasicBlock metadataIntermediate = new GraphTransformerIntermediateBasicBlock();
metadataIntermediate.correspondingGraphNodes.Add(link);
intermediateBasicBlock.transformationMetadata.Add(metadataIntermediate);
// create intermediate exit branch
UnconditionalBranchTarget intermediateBasicBlockExitBranch = new UnconditionalBranchTarget();
intermediateBasicBlockExitBranch.sourceBasicBlock = intermediateBasicBlock;
intermediateBasicBlock.exitBranch = intermediateBasicBlockExitBranch;
cfgManipulator.insertBasicBlockBetweenBranch(opaqueExitBranch, false, intermediateBasicBlock, intermediateBasicBlockExitBranch);
break;
}
// "Random" opaque predicate.
case 2: {
BasicBlock opaqueStartBasicBlock = null;
if ((targetBranch as SwitchBranchTarget) != null) {
SwitchBranchTarget tempTargetBranch = (targetBranch as SwitchBranchTarget);
var destinationBlock = tempTargetBranch.takenTarget[currentValidPathId];
this.createCodeRandomPredicate(ref opaqueStartBasicBlock, ref opaqueExitBranch, link, currentNodeLocal);
bool chooseBranch = prng.Next(1) == 0;
cfgManipulator.insertBasicBlockBetweenBranch(tempTargetBranch, currentValidPathId, opaqueStartBasicBlock, opaqueExitBranch, chooseBranch);
}
else {
throw new ArgumentException("Not implemented yet.");
}
break;
}
default:
throw new ArgumentException("This case should never be reached.");
}
}
// this function injects an opaque predicate to the target branch
private void injectOpaquePredicateCode(CfgManipulator cfgManipulator, Target target, ref ConditionalBranchTarget opaqueExitBranch, IBranchTarget targetBranch, BasicBlockGraphNodeLink link, int currentValidPathId, int opaquePredicate, LocalDefinition currentNodeLocal) {
// create "true" or "false" opaque predicate and add it to the code
switch (opaquePredicate) {
// "true" opaque predicate
case 0: {
BasicBlock opaqueStartBasicBlock = null;
this.createCodeTruePredicate(ref opaqueStartBasicBlock, ref opaqueExitBranch, link, currentNodeLocal);
// inject target branch with opaque predicate
if ((targetBranch as SwitchBranchTarget) != null) {
SwitchBranchTarget tempTargetBranch = (targetBranch as SwitchBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempTargetBranch, currentValidPathId, opaqueStartBasicBlock, opaqueExitBranch, true);
}
else {
throw new ArgumentException("Not implemented yet.");
}
// set template semantic id of dead code basic block
BasicBlock deadCodeBasicBlock = opaqueExitBranch.notTakenTarget;
GraphTransformerDeadCodeBasicBlock deadCodeMetadata = (deadCodeBasicBlock.transformationMetadata.ElementAt(0) as GraphTransformerDeadCodeBasicBlock);
deadCodeMetadata.semanticId = target.basicBlock.semanticId;
break;
}
// "false" opaque predicate
case 1: {
BasicBlock opaqueStartBasicBlock = null;
this.createCodeFalsePredicate(ref opaqueStartBasicBlock, ref opaqueExitBranch, link, currentNodeLocal);
// inject target branch with opaque predicate
if ((targetBranch as SwitchBranchTarget) != null) {
SwitchBranchTarget tempTargetBranch = (targetBranch as SwitchBranchTarget);
cfgManipulator.insertBasicBlockBetweenBranch(tempTargetBranch, currentValidPathId, opaqueStartBasicBlock, opaqueExitBranch, false);
}
else {
throw new ArgumentException("Not implemented yet.");
}
// set template semantic id of dead code basic block
BasicBlock deadCodeBasicBlock = opaqueExitBranch.takenTarget;
GraphTransformerDeadCodeBasicBlock deadCodeMetadata = (deadCodeBasicBlock.transformationMetadata.ElementAt(0) as GraphTransformerDeadCodeBasicBlock);
deadCodeMetadata.semanticId = target.basicBlock.semanticId;
break;
}
// "Random" opaque predicate.
case 2: {
BasicBlock opaqueStartBasicBlock = null;
if((targetBranch as SwitchBranchTarget) != null) {
SwitchBranchTarget tempTargetBranch = (targetBranch as SwitchBranchTarget);
var destinationBlock = tempTargetBranch.takenTarget[currentValidPathId];
this.createCodeRandomPredicate(ref opaqueStartBasicBlock, ref opaqueExitBranch, link, currentNodeLocal);
bool chooseBranch = prng.Next(1) == 0;
cfgManipulator.insertBasicBlockBetweenBranch(tempTargetBranch, currentValidPathId, opaqueStartBasicBlock, opaqueExitBranch, chooseBranch);
}
else {
throw new ArgumentException("Not implemented yet.");
}
break;
}
default:
throw new ArgumentException("This case should never be reached.");
}
}
// this function generates code to move the current pointer to the next child node (or start node if there is no next child node)
private BasicBlock createCodeNextNode(IBranchTarget usedExitBranch, BasicBlockGraphNodeLink graphLink, LocalDefinition currentNodeLocal, int index, bool correctNextNode) {
// create graph transformer metadata for the basic blocks
GraphTransformerNextNodeBasicBlock metadata = new GraphTransformerNextNodeBasicBlock();
metadata.correctNextNode = correctNextNode;
metadata.correspondingGraphNodes.Add(graphLink);
// create new basic block
BasicBlock nextNodeBasicBlock = new BasicBlock();
nextNodeBasicBlock.startIdx = 0;
nextNodeBasicBlock.endIdx = 0;
nextNodeBasicBlock.transformationMetadata.Add(metadata);
nextNodeBasicBlock.operations.Add(this.helperClass.createNewOperation(OperationCode.Ldloc, currentNodeLocal));
nextNodeBasicBlock.operations.Add(this.helperClass.createNewOperation(OperationCode.Ldc_I4, index)); // TODO perhaps a more dynamically calculated index?
nextNodeBasicBlock.operations.Add(this.helperClass.createNewOperation(OperationCode.Callvirt, this.interfaceChildNodesGet));
nextNodeBasicBlock.operations.Add(this.helperClass.createNewOperation(OperationCode.Stloc, currentNodeLocal));
// check which exit branch is used to inject the code to the cfg and generate code for it accordingly
if ((usedExitBranch as NoBranchTarget) != null) {
nextNodeBasicBlock.operations.Add(this.helperClass.createNewOperation(OperationCode.Nop));
}
else if ((usedExitBranch as UnconditionalBranchTarget) != null) {
nextNodeBasicBlock.operations.Add(this.helperClass.createNewOperation(OperationCode.Br));
}
else {
throw new ArgumentException("Do not know how to generate code for given exit branch.");
}
// add exit branch to newly created basic block
nextNodeBasicBlock.exitBranch = usedExitBranch;
usedExitBranch.sourceBasicBlock = nextNodeBasicBlock;
return nextNodeBasicBlock;
}