SMPFunction.cpp

#if SMP_DEBUG_CONTROLFLOW
	SMP_msg("SMPFunction::Analyze: set stack frame info.\n");
#endif
	if (!(this->HasSharedChunks())) {

		this->SetStackFrameInfo();

	} // end if not shared chunks
	else { // has shared chunks; still want to compute stack frame info
#ifdef SMP_DEBUG_FUNC
		SMP_msg(" %s has shared chunks \n", this->GetFuncName());
#endif
		// Figure out the stack frame and related info.
		this->SetStackFrameInfo();
	}

	this->MarkFunctionSafe();

#if SMP_COUNT_MEMORY_ALLOCATIONS
	SMPInstCount += ((unsigned long) this->Instrs.size());
	SMPBlockCount += ((unsigned long) this->Blocks.size());
	SMPLocalVarCount += ((unsigned long) this->LocalVarTable.size());
#endif

} // end of SMPFunction::AdvancedAnalysis()

// Count call targets that have not been processed.
size_t SMPFunction::UnprocessedCalleesCount(void) {
	size_t UnprocessedTargetsCount = 0;

	size_t TargetIndex;
	for (TargetIndex = 0; TargetIndex < this->AllCallTargets.size(); ++TargetIndex) {
		SMPFunction *CurrTarget = this->GetProg()->FindFunction(this->AllCallTargets.at(TargetIndex));
		if (NULL == CurrTarget) {
#if 0
			// Bad call targets are removed in AdvancedAnalysis(), which comes later.
			SMP_msg("ERROR: NULL CallTarget in UnprocessedCalleesCount() at TargetIndex %zu \n", TargetIndex);
#endif
		}
		else if (!(CurrTarget->IsFuncProcessed())) {
			++UnprocessedTargetsCount;
		}
	}
	return UnprocessedTargetsCount;
} // end of SMPFunction::UnprocessedCalleesCount()

ea_t SMPFunction::GetFirstUnprocessedCallee(void) {
	ea_t CalleeAddr = BADADDR;
	size_t TargetIndex;
	for (TargetIndex = 0; TargetIndex < this->AllCallTargets.size(); ++TargetIndex) {
		ea_t TargetAddr = this->AllCallTargets.at(TargetIndex);
		SMPFunction *CurrTarget = this->GetProg()->FindFunction(TargetAddr);
		if ((NULL != CurrTarget) && (!(CurrTarget->IsFuncProcessed()))) {
			CalleeAddr = TargetAddr;
			break;
		}
	}
	return CalleeAddr;
} // end of SMPFunction::GetFirstUnprocessedCallee()

// Is the code starting at TargetAddr a non-shared chunk that jumps back into our function?
//  If so, it can be incorporated into our function rather than treated as a separate function.
//  This method is called only when we see a jump outside our function, and it is looking for
//  code fragments that are not really functions (i.e. don't have a stack frame, jump straight back
//  into our function after executing a few instructions, not a chunk shared among other functions).
//  These code fragments are found in the locking and unlocking code of the gcc stdlib, for example.
bool SMPFunction::FindDistantCodeFragment(ea_t TargetAddr) {
	bool PrivateFragment = false;
	func_t *TargetFunc = get_func(TargetAddr);
	if (TargetFunc) {
		// Determine if we are dealing with shared chunks.
		size_t ChunkCounter = 0;
		func_tail_iterator_t FuncTail(TargetFunc);
		for (bool ChunkOK = FuncTail.main(); ChunkOK; ChunkOK = FuncTail.next()) {
			++ChunkCounter;
		}
		if (1 < ChunkCounter) {
			SMP_msg("INFO: Code fragment at %x is shared chunk.\n", TargetAddr);
		}
		else {
			bool JumpsBackIntoCurrentFunc = false;
			bool HasReturnInstruction = false;
			bool AllocatesStackFrame = false;
		 	for (bool ChunkOK = FuncTail.main(); ChunkOK; ChunkOK = FuncTail.next()) {
				const area_t &CurrChunk = FuncTail.chunk();
				++ChunkCounter;
				// Build the instruction and block lists for the function.
				for (ea_t addr = CurrChunk.startEA; addr < CurrChunk.endEA;	addr = get_item_end(addr)) {
					flags_t InstrFlags = getFlags(addr);
					if (isHead(InstrFlags) && isCode(InstrFlags)) {
						SMPInstr *CurrInst = new SMPInstr(addr);
						// Fill in the instruction data members.
						CurrInst->Analyze();
						// Search for two negative indicators (stack allocations and returns)
						//  and one positive indicator (jump back into this function).
						if (CurrInst->MDIsReturnInstr()) {
							HasReturnInstruction = true;
							break;
						}
						else if (CurrInst->MDIsFrameAllocInstr()) {
							AllocatesStackFrame = true;
							break;
						}
						else {
							SMPitype FlowType = CurrInst->GetDataFlowType();
							if ((JUMP == FlowType) || (INDIR_JUMP == FlowType)) {
								if (CurrInst->BuildRTL()) {
									ea_t FragmentJumpTarget = CurrInst->GetJumpTarget();
									if ((FragmentJumpTarget >= this->FirstEA) && (FragmentJumpTarget <= this->FuncInfo.endEA)) {
										JumpsBackIntoCurrentFunc = true;
									}
								}
							}
						}
					} // end if isHead() and isCode()
				} // end for all addrs in chunk
			} // end for all chunks (there will only be one)
			PrivateFragment = (JumpsBackIntoCurrentFunc && (!HasReturnInstruction) && (!AllocatesStackFrame));
		} // end if (1 < ChunkCounter) ... else ...
	} // end if (TargetFunc)

	return PrivateFragment;
} // end of SMPFunction::FindDistantCodeFragment()

// Free memory that is no longer needed after loop 2 of SMPProgram::Analyze().
void SMPFunction::FreeUnusedMemory2(void) {
	size_t UnusedElements;
	size_t CurrSize;

#if 0
	// Go through vector containers and resize to current capacity, if the vector
	//  has been fully computed by the time SMPProgram:Analyze() loop 2 completes.
	CurrSize = this->DirectCallTargets.size();
	UnusedElements = this->DirectCallTargets.capacity() - CurrSize;
	if (0 < UnusedElements) {
		UnusedIntCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<ea_t>(this->DirectCallTargets).swap(this->DirectCallTargets);
#else
		this->DirectCallTargets.resize(CurrSize);
#endif
	}

	CurrSize = this->IndirectCallTargets.size();
	UnusedElements = this->IndirectCallTargets.capacity() - CurrSize;
	if (0 < UnusedElements) {
		UnusedIntCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<ea_t>(this->IndirectCallTargets).swap(this->IndirectCallTargets);
#else
		this->IndirectCallTargets.resize(CurrSize);
#endif
	}
#endif

	CurrSize = this->AllCallTargets.size();
	UnusedElements = this->AllCallTargets.capacity() - CurrSize;
	if (0 < UnusedElements) {
		UnusedIntCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<ea_t>(this->AllCallTargets).swap(this->AllCallTargets);
#else
		this->AllCallTargets.resize(CurrSize);
#endif
	}

	CurrSize = this->SavedRegLoc.size();
	UnusedElements = this->SavedRegLoc.capacity() - CurrSize;
	if (0 < UnusedElements) {
		UnusedIntCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<int>(this->SavedRegLoc).swap(this->SavedRegLoc);
#else
		this->SavedRegLoc.resize(CurrSize);
#endif
	}

	CurrSize = this->RPOBlocks.size();
	UnusedElements = this->RPOBlocks.capacity() - CurrSize;
	if (0 < UnusedElements) {
		list<SMPBasicBlock *>::iterator DummyIter = this->Blocks.end();
		UnusedIntCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<SMPBasicBlock *>(this->RPOBlocks).swap(this->RPOBlocks);
#else
		this->RPOBlocks.resize(CurrSize, DummyIter);
#endif
	}

	CurrSize = this->LocalVarTable.size();
	UnusedElements = this->LocalVarTable.capacity() - CurrSize;
	if (0 < UnusedElements) {
		struct LocalVar DummyVar;
		DummyVar.offset = 0;
		DummyVar.size = 0;
		UnusedStructCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<struct LocalVar>(this->LocalVarTable).swap(this->LocalVarTable);
#else
		this->LocalVarTable.resize(CurrSize, DummyVar);
#endif
	}

	CurrSize = this->StackFrameMap.size();
	UnusedElements = this->StackFrameMap.capacity() - CurrSize;
	if (0 < UnusedElements) {
		struct StackFrameEntry DummyEntry;
		DummyEntry.offset = 0;
		DummyEntry.VarPtr = NULL;
		UnusedStructCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<struct StackFrameEntry>(this->StackFrameMap).swap(this->StackFrameMap);
#else
		this->StackFrameMap.resize(CurrSize, DummyEntry);
#endif
	}

	CurrSize = this->FineGrainedStackTable.size();
	UnusedElements = this->FineGrainedStackTable.capacity() - CurrSize;
	if (0 < UnusedElements) {
		struct FineGrainedInfo DummyFG;
		DummyFG.SignMiscInfo = 0;
		DummyFG.SizeInfo = 0;
		UnusedStructCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<struct FineGrainedInfo>(this->FineGrainedStackTable).swap(this->FineGrainedStackTable);
#else
		this->FineGrainedStackTable.resize(CurrSize, DummyFG);
#endif
	}

	return;
} // end of SMPFunction::FreeUnusedMemory2()

// Free memory that is no longer needed after loop 3 of SMPProgram::Analyze().
void SMPFunction::FreeUnusedMemory3(void) {
	size_t UnusedElements;
	size_t CurrSize;

	// Go through vector containers and resize to current capacity, if the vector
	//  has been fully computed by the time SMPProgram:Analyze() loop 2 completes.
	CurrSize = this->ReturnRegTypes.size();
	UnusedElements = this->ReturnRegTypes.capacity() - CurrSize;
	if (0 < UnusedElements) {
		UnusedIntCount += (unsigned long) UnusedElements;
#if SMP_SHRINK_TO_FIT
		std::vector<SMPOperandType>(this->ReturnRegTypes).swap(this->ReturnRegTypes);
#else		
		this->ReturnRegTypes.resize(CurrSize);
#endif
	}

	return;
} // end of SMPFunction::FreeUnusedMemory3()

// Free memory that is no longer needed after type inference (loop 4 of SMPProgram::Analyze()).
void SMPFunction::FreeUnusedMemory4(void) {
	this->KillSet.clear();
	this->LiveOutSet.clear();
	this->LiveInSet.clear();
	this->StackFrameMap.clear();
	this->BlocksDefinedIn.clear();

#if SMP_SHRINK_TO_FIT
	std::set<op_t, LessOp>(this->KillSet).swap(this->KillSet);
	std::set<op_t, LessOp>(this->LiveOutSet).swap(this->LiveOutSet);
	std::set<op_t, LessOp>(this->LiveInSet).swap(this->LiveInSet);
#endif

	list<SMPBasicBlock *>::iterator BlockIter;
	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		(*BlockIter)->FreeUnusedMemory4();
	}
	return;
} // end of SMPFunction::FreeUnusedMemory4()

// Free SSA data structures that are no longer needed when all SSA numbers have
//  been recorded in DEFs and USEs.
void SMPFunction::FreeSSAMemory(void) {
	this->IDom.clear();
	this->DomTree.clear();
	this->BlocksDefinedIn.clear();
	this->SSACounter.clear();
	this->SSAStack.clear();

#if SMP_SHRINK_TO_FIT
	vector<int>(this->IDom).swap(this->IDom);
	vector<pair<int, list<int> > >(this->DomTree).swap(this->DomTree);
	vector<list<int> >(this->BlocksDefinedIn).swap(this->BlocksDefinedIn);
	vector<int>(this->SSACounter).swap(this->SSACounter);
	vector<list<int> >(this->SSAStack).swap(this->SSAStack);
#endif

	list<SMPBasicBlock *>::iterator BlockIter;
	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		(*BlockIter)->FreeSSAMemory();
	}
	return;
} // end of SMPFunction::FreeSSAMemory()

// For each instruction, mark the non-flags-reg DEFs as having live
//  metadata (mmStrata needs to fetch and track this metadata for this
//  instruction) or dead metadata (won't be used as addressing reg, won't
//  be stored to memory, won't be returned to caller).
void SMPFunction::AnalyzeMetadataLiveness(void) {
	bool changed;
	int BaseReg;
	int IndexReg;
	ushort ScaleFactor;
	ea_t offset;
	op_t BaseOp = InitOp, IndexOp = InitOp, ReturnOp = InitOp;
	BaseOp.type = o_reg;
	IndexOp.type = o_reg;
	ReturnOp.type = o_reg;
	list<SMPInstr *>::iterator InstIter;
	list<SMPInstr *>::reverse_iterator RevInstIter;
	set<DefOrUse, LessDefUse>::iterator CurrDef;
	set<DefOrUse, LessDefUse>::iterator CurrUse;
	set<DefOrUse, LessDefUse>::iterator NextUse;
	bool DebugFlag = false;
	bool UseFP = this->UsesFramePointer();
	int IterationCount = 0;

#if SMP_DEBUG_DATAFLOW
	if (0 == strcmp("uw_frame_state_for", this->GetFuncName())) {
		DebugFlag = true;
	}
#endif

	do {
		changed = false;
		++IterationCount;
		bool SafeMemDest;
		if (DebugFlag) {
			SMP_msg("AnalyzeMetadataLiveness iteration count: %d \n", IterationCount);
		}
		for (RevInstIter = this->Instrs.rbegin(); RevInstIter != this->Instrs.rend(); ++RevInstIter) {
			SMPInstr *CurrInst = (*RevInstIter);
			ea_t InstAddr = CurrInst->GetAddr();
			SafeMemDest = false;  // true for some SafeFunc instructions
			// Skip the SSA marker instruction.
			if (NN_fnop == CurrInst->GetCmd().itype)
				continue;

			if (DebugFlag) {
				SMP_msg("Inst addr: %x \n", CurrInst->GetAddr());
			}
			CurrDef = CurrInst->GetFirstDef();
			while (CurrDef != CurrInst->GetLastDef()) {
				if (DEF_METADATA_UNANALYZED == CurrDef->GetMetadataStatus()) {
					op_t DefOp = CurrDef->GetOp();
					// Handle special registers never used as address regs.
					if (DefOp.is_reg(X86_FLAGS_REG)
						|| ((o_trreg <= DefOp.type) && (o_xmmreg >= DefOp.type))) {
						CurrDef = CurrInst->SetDefMetadata(DefOp,
							DEF_METADATA_UNUSED);
						changed = true;
					}
					else if (MDIsStackOrFramePointerReg(DefOp, UseFP)) {
						// Stack pointer register DEFs always have live
						//  metadata, but we don't need to propagate back
						//  through particular DEF-USE chains.
						CurrDef = CurrInst->SetDefMetadata(DefOp, DEF_METADATA_USED);
						changed = true;
					}
					else if ((o_mem <= DefOp.type) && (o_displ >= DefOp.type)) {
						// DEF is a memory operand. The addressing registers
						//  therefore have live metadata, and the memory metadata is live.
						// EXCEPTION: If the function is Safe, then direct stack writes
						//  to local variables (above the outgoing args area of the frame)
						//  are not live metadata, and there will be no indirect local frame
						//  writes, by definition of "safe." So, for safe funcs, only
						//  the o_mem (globals) and indirect writes are live metadata.
						if (this->SafeFunc && MDIsStackAccessOpnd(DefOp, this->UseFP)
							&& (!this->WritesAboveLocalFrame(DefOp, CurrInst->AreDefsNormalized()))
							&& (!this->IsInOutgoingArgsRegion(DefOp))) {
							++CurrDef;
							SafeMemDest = true;
							continue;
						}
						CurrDef = CurrInst->SetDefMetadata(DefOp, DEF_METADATA_USED);
						changed = true;
						MDExtractAddressFields(DefOp, BaseReg, IndexReg,
							ScaleFactor, offset);
						if (R_none != BaseReg) {
							BaseOp.reg = MDCanonicalizeSubReg((ushort) BaseReg);
							BaseOp.dtyp = dt_dword; // canonical 32-bit width
							if (MDIsStackOrFramePointerReg(BaseOp, UseFP)) {
								; // do nothing; DEF handled by case above
							}
							else {
								CurrUse = CurrInst->FindUse(BaseOp);
								if (CurrUse == CurrInst->GetLastUse()) {
									SMP_msg("FATAL ERROR: BaseReg %d not in USE list at %x for %s\n",
										BaseOp.reg, CurrInst->GetAddr(),
										CurrInst->GetDisasm());
								}
								assert(CurrUse != CurrInst->GetLastUse());
								if (this->IsGlobalName(BaseOp)) {
									changed |= this->PropagateGlobalMetadata(BaseOp,
										DEF_METADATA_USED, CurrUse->GetSSANum(), InstAddr);
								}
								else {
									changed |= CurrInst->GetBlock()->PropagateLocalMetadata(BaseOp,
										DEF_METADATA_USED, CurrUse->GetSSANum(), InstAddr);
								}
							}
						} // end if R_none != BaseReg
						if (R_none != IndexReg) {
							IndexOp.reg = MDCanonicalizeSubReg((ushort) IndexReg);
							IndexOp.dtyp = dt_dword; // canonical 32-bit width
							if (MDIsStackOrFramePointerReg(IndexOp, UseFP)) {
								; // do nothing; DEF handled by case above
							}
							else {
								CurrUse = CurrInst->FindUse(IndexOp);
								if (CurrUse == CurrInst->GetLastUse()) {
									SMP_msg("FATAL ERROR: IndexReg %d not in USE list at %x for %s\n",
										IndexOp.reg, CurrInst->GetAddr(),
										CurrInst->GetDisasm());
								}
								assert(CurrUse != CurrInst->GetLastUse());
								if (0 != ScaleFactor) {
									; // mmStrata knows scaled reg is NUMERIC
									// ... its metadata is not fetched
								}
								else if (this->IsGlobalName(IndexOp)) {
									changed |= this->PropagateGlobalMetadata(IndexOp,
										DEF_METADATA_USED, CurrUse->GetSSANum(), InstAddr);
								}
								else {
									changed |= CurrInst->GetBlock()->PropagateLocalMetadata(IndexOp,
										DEF_METADATA_USED, CurrUse->GetSSANum(), InstAddr);
								}
							}
						} // end if R_none != IndexReg
					} // end if X86_FLAGS_REG .. else if stack ptr ... 
				} // end if unanalyzed metadata usage
				++CurrDef;
			} // end while processing DEFs
			if ((RETURN == CurrInst->GetDataFlowType())
				|| (CurrInst->IsTailCall())   // quasi-return
				|| (CALL == CurrInst->GetDataFlowType())
				|| (INDIR_CALL == CurrInst->GetDataFlowType())) {
				// The EAX and EDX registers can be returned to the caller,
				//  which might use their metadata. They show up as USEs
				//  of the return instruction. Some library functions
				//  pass return values in non-standard ways. e.g. through
				//  EBX or EDI, so we treat all return regs the same.
				// For CALL instructions, values can be passed in caller-saved
				//  registers, unfortunately, so the metadata is live-in.
				CurrUse = CurrInst->GetFirstUse();
				while (CurrUse != CurrInst->GetLastUse()) {
					NextUse = CurrUse;
					++NextUse;
					ReturnOp = CurrUse->GetOp();
					if (DebugFlag) {
						SMP_msg("ReturnOp: ");
						PrintOperand(ReturnOp);
						SMP_msg("\n");
					}
					if ((o_reg == ReturnOp.type) &&
						(!MDIsStackOrFramePointerReg(ReturnOp, UseFP)) &&
						(!ReturnOp.is_reg(X86_FLAGS_REG))) {
						if (this->IsGlobalName(ReturnOp)) {
							changed |= this->PropagateGlobalMetadata(ReturnOp,
									DEF_METADATA_USED, CurrUse->GetSSANum(), InstAddr);
						}
						else {
							changed |= CurrInst->GetBlock()->PropagateLocalMetadata(ReturnOp,
									DEF_METADATA_USED, CurrUse->GetSSANum(), InstAddr);
						}
					}
					CurrUse = NextUse;
				} // end while all USEs
			} // end if return or call
			else if (CurrInst->HasDestMemoryOperand() 
				|| CurrInst->MDIsPushInstr()) {
				// Memory writes cause a lot of metadata usage.
				//  Addressing registers in the memory destination
				//  have live metadata used in bounds checking. The
				//  register being stored to memory could end up being
				//  used in some other bounds checking, unless we 
				//  have precise memory tracking and know that it
				//  won't.
				// We handled the addressing registers above, so we
				//  handle the register written to memory here.
				// The same exception applies as above: If the destination
				//  memory operand is not a stack write, then safe functions
				//  do not need to track the metadata.
				// If we push a register and have callees, the metadata could
				//  be live, if the callee gets its incoming args from our push
				//  instructions.
				if (SafeMemDest && !(CurrInst->MDIsPushInstr() && !this->IsLeaf())) {
					continue;  // go to next instruction
				}
				CurrUse = CurrInst->GetFirstUse();
				while (CurrUse != CurrInst->GetLastUse()) {
					NextUse = CurrUse;
					++NextUse;
					op_t UseOp = CurrUse->GetOp();
					// NOTE: **!!** To be less conservative, we
					//  should propagate less for exchange category
					//  instructions.
					if ((UseOp.type == o_reg) && (!MDIsStackOrFramePointerReg(UseOp, UseFP)) && (!UseOp.is_reg(X86_FLAGS_REG))) {
						if (this->IsGlobalName(UseOp)) {
							changed |= this->PropagateGlobalMetadata(UseOp,
									DEF_METADATA_USED, CurrUse->GetSSANum(), InstAddr);
						}
						else {
							changed |= CurrInst->GetBlock()->PropagateLocalMetadata(UseOp,
									DEF_METADATA_USED, CurrUse->GetSSANum(), InstAddr);
						}
					} // end if register
					CurrUse = NextUse;
				} // end while all USEs
			} // end if call or return else if memdest ...
		} // end for all instructions
	} while (changed);

	// All DEFs that still have status DEF_METADATA_UNANALYZED can now
	//  be marked as DEF_METADATA_UNUSED.
	for (InstIter = this->Instrs.begin(); InstIter != this->Instrs.end(); ++InstIter) {
		SMPInstr *CurrInst = (*InstIter);
		if (NN_fnop == CurrInst->GetCmd().itype)
			continue;
		CurrDef = CurrInst->GetFirstDef();
		while (CurrDef != CurrInst->GetLastDef()) {
			if (DEF_METADATA_UNANALYZED == CurrDef->GetMetadataStatus()) {
				CurrDef = CurrInst->SetDefMetadata(CurrDef->GetOp(),
					DEF_METADATA_UNUSED);
				assert(CurrDef != CurrInst->GetLastDef());
			}
			++CurrDef;
		}
	}

	return;
} // end of SMPFunction::AnalyzeMetadataLiveness() 

// Propagate the metadata Status for UseOp/SSANum to its global DEF.
// Return true if successful.
bool SMPFunction::PropagateGlobalMetadata(op_t UseOp, SMPMetadataType Status, int SSANum, ea_t UseAddr) {
	bool changed = false;
	bool UseFP = this->UsesFramePointer();

	if ((0 > SSANum) || (o_void == UseOp.type) || (!MDIsDataFlowOpnd(UseOp, UseFP)) || MDIsIndirectMemoryOpnd(UseOp, UseFP))
		return false;

	// Find the DEF of UseOp with SSANum.
	ea_t DefAddr;
	SMPBasicBlock *UseBlock;
	SMPBasicBlock *DefBlock;

	if (UseAddr > this->GetNumBlocks()) { // UseAddr is an inst addr
		UseBlock = this->GetBlockFromInstAddr(UseAddr);
	}
	else { // UseAddr is a block number
		UseBlock = this->GetBlockByNum((size_t) UseAddr);
	}

	DefAddr = UseBlock->GetUltimateDefAddr(UseOp, UseAddr, SSANum, false);

	if (BADADDR == DefAddr) {
		return changed;
	}

	if (DefAddr > this->GetNumBlocks()) { // found a DEF inst.
		SMPInstr *CurrInst = this->GetInstFromAddr(DefAddr);
		ea_t InstAddr = DefAddr;
		DefBlock = this->GetBlockFromInstAddr(DefAddr);
		set<DefOrUse, LessDefUse>::iterator CurrDef;
		set<DefOrUse, LessDefUse>::iterator CurrUse;
		CurrDef = CurrInst->FindDef(UseOp);
		assert(CurrDef != CurrInst->GetLastDef());
		assert(SSANum == CurrDef->GetSSANum());
		if (Status != CurrDef->GetMetadataStatus()) {
			CurrDef = CurrInst->SetDefMetadata(UseOp, Status);
			changed = (CurrDef != CurrInst->GetLastDef());
			bool PropThroughUses = changed;

			// If source operand was memory, we have two cases.
			//  (1) The instruction could be a load, in which
			//  case we should simply terminate the
			//  propagation, because the prior DEF of a memory
			//  location is always considered live metadata
			//  already, and we do not want to propagate liveness
			//  to the address regs in the USE list.
			//  EXCEPTION: For safe funcs, we propagate liveness
			//   for stack locations.
			//  (2) We could have an arithmetic operation such
			//  as reg := reg arithop memsrc. In this case, we
			//  still do not want to propagate through the memsrc,
			//  (with the same safe func EXCEPTION),
			//  but the register is both DEF and USE and we need
			//  to propagate through the register.
			if (CurrInst->HasSourceMemoryOperand()) {
				if (this->SafeFunc) {
					op_t MemSrcOp = CurrInst->MDGetMemUseOp();
					assert(o_void != MemSrcOp.type);
					if (MDIsDirectStackAccessOpnd(MemSrcOp, this->UseFP)) {
						// We have a SafeFunc stack access. This is
						//  the EXCEPTION case where we want to
						//  propagate metadata liveness for a memory
						//  location.
						CurrUse = CurrInst->FindUse(MemSrcOp);
						assert(CurrUse != CurrInst->GetLastUse());
						if (this->IsGlobalName(MemSrcOp)) {
							changed |= this->PropagateGlobalMetadata(MemSrcOp,
								Status, CurrUse->GetSSANum(), InstAddr);
						}
						else {
							changed |= CurrInst->GetBlock()->PropagateLocalMetadata(MemSrcOp,
								Status, CurrUse->GetSSANum(), InstAddr);
						}
					} // end if stack access operand
				} // end if SafeFunc
				if (3 == CurrInst->GetOptType()) { // move inst
					PropThroughUses = false; // load address regs are not live metadata
				}
				else if ((5 == CurrInst->GetOptType())
					|| (NN_and == CurrInst->GetCmd().itype)
					|| (NN_or == CurrInst->GetCmd().itype)
					|| (NN_xor == CurrInst->GetCmd().itype)) {
					// add, subtract, and, or with memsrc
					// Find the DEF reg in the USE list.
					CurrUse = CurrInst->FindUse(UseOp);
					assert(CurrUse != CurrInst->GetLastUse());
					changed |= this->PropagateGlobalMetadata(UseOp,
						Status, CurrUse->GetSSANum(), InstAddr);
					PropThroughUses = false;
				}
			} // end if memory source

			// Now, propagate the metadata status to all the
			//  non-memory, non-flags-reg, non-special-reg 
			//  (i.e. regular registers) USEs.
			if (PropThroughUses) {
				CurrUse = CurrInst->GetFirstUse();
				while (CurrUse != CurrInst->GetLastUse()) {
					op_t CurrUseOp = CurrUse->GetOp();
					// NOTE: **!!** To be less conservative, we
					//  should propagate less for exchange category
					//  instructions.
					if ((CurrUseOp.type == o_reg) && (!MDIsStackOrFramePointerReg(CurrUseOp, UseFP))
						&& (!CurrUseOp.is_reg(X86_FLAGS_REG))) {

						if (this->IsGlobalName(CurrUseOp)) {
							changed |= this->PropagateGlobalMetadata(CurrUseOp,
								Status, CurrUse->GetSSANum(), InstAddr);
						}
						else {
							changed |= CurrInst->GetBlock()->PropagateLocalMetadata(CurrUseOp,
								Status, CurrUse->GetSSANum(), InstAddr);
						}
					}
					++CurrUse;
				} // end while all USEs
			}
		}
	}

	else { // Found a DEF block number in DefAddr.
		// Check the Phi functions
		DefBlock = this->GetBlockByNum((size_t) DefAddr);
		set<SMPPhiFunction, LessPhi>::iterator DefPhi;
		DefPhi = DefBlock->FindPhi(UseOp);
		assert(DefPhi != DefBlock->GetLastPhi());
		assert(SSANum == DefPhi->GetDefSSANum());
		if (Status != DefPhi->GetDefMetadata()) {
			DefPhi = DefBlock->SetPhiDefMetadata(UseOp, Status);
			changed = true;
			// If the Phi DEF has live metadata, then the Phi
			//  USEs each have live metadata. Propagate.
			int UseSSANum;
			for (size_t index = 0; index < DefPhi->GetPhiListSize(); ++index) {
				UseSSANum = DefPhi->GetUseSSANum(index);
				// UseSSANum can be -1 in some cases because
				//  we conservatively make EAX and EDX be USEs
				//  of all return instructions, when the function
				//  might have a void return type, making it
				//  appear as if an uninitialized EAX or EDX
				//  could make it to the return block.
				if (0 <= UseSSANum) {
					changed |= this->PropagateGlobalMetadata(UseOp,	Status, UseSSANum, DefAddr);
				}
			}
		}

	} // end if (DefAddr is inst addr) else ... [DefAddr is block number]

	return changed;
} // end of SMPFunction::PropagateGlobalMetadata()

// Find consecutive DEFs of the same type and mark the second one redundant.
void SMPFunction::FindRedundantMetadata(void) {
	list<SMPBasicBlock *>::iterator BlockIter;
	SMPBasicBlock *CurrBlock;
	bool changed = false;

	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		CurrBlock = (*BlockIter);
		changed |= CurrBlock->FindRedundantLocalMetadata(this->SafeFunc);
	}
	return;
} // end of SMPFunction::FindRedundantMetadata()

// Perform SCCP to find constant values for DEFs, store in this->ConstantDefs
void SMPFunction::SparseConditionalConstantPropagation(void) {
	// We perform the SCCP (Sparse Conditional Constant Propagation) algorithm
	//  as found in Cooper & Torczon, "Engineering a Compiler."

	return;
} // end of SMPFunction::SparseConditionalConstantPropagation() 

// Do we not care if DEF underflowed, due to how it is used?
bool SMPFunction::IsBenignUnderflowDEF(op_t DefOp, int DefSSANum, size_t DefAddr, int &IdiomCode) {
	bool benign = false;
	list<SMPInstr *>::iterator InstIter;
	set<DefOrUse, LessDefUse>::iterator DefIter, UseIter;
	int UseSSANum;
	SMPOperandType DefType;

	// We are looking to suppress overflow and underflow warnings on the following
	//  code sequence: PTR1-PTR2+1 gets a loop invariant code motion optimization
	//  that pulls  temp := 1-PTR2 out of the loop, and leaves temp2 := PTR1+temp
	//  inside the loop. The hoisted subtraction could underflow, and the addition
	//  that is not hoisted could overflow. The net effect of these two instructions
	//  is benign, however, so we want to suppress underflow and overflow checks on
	//  both of them, but only if we can match the pair of instructions.
	
	// We know that DefOp/DefAddr/DefSSANum refer to a subtraction instruction that
	//  produces a NEGATEDPTR result. We only need to find the paired addition instruction
	//  that USEs the same SSA name to produce a PTROFFSET result to prove that we have
	//  a case of benign underflow and overflow. If we find such a pair, we will mark
	//  both of their DEF results as benign overflows to suppress overflow checks.

	// PAINFUL: Linear search of instructions. Need to address this in the future.
	//  Perhaps we should have a map of UseHashValue to InstAddr, but that is more
	//  memory consumption. Sure would be useful, though.
	for (InstIter = this->Instrs.begin(); InstIter != this->Instrs.end(); ++InstIter) {
		SMPInstr *CurrInst = (*InstIter);
		UseIter = CurrInst->FindUse(DefOp);
		UseSSANum = UseIter->GetSSANum();
		if (UseSSANum == DefSSANum) {
			// Only remaining question: Do we produce a PTROFFSET in CurrInst? (If we do,
			//  that implies we had an addition, so we don't need to check that.)
			DefIter = CurrInst->GetFirstNonFlagsDef();
			DefType = DefIter->GetType();
			// NOTE: Make this more general. What if we just move the NEGATEDPTR into a register
			//  and then the next instruction, with different SSA name, produces the PTROFFSET?
			//  !!!!!*****!!!!!
			if (IsEqType(DefType, PTROFFSET)) {
				// Found a pair. Mark both DEFs as benign and return true.
				benign = true;
				IdiomCode = 4;
				// Note that we have two possibilities for the addition. The NEGATEDPTR could be
				//  both the DEF and a USE, e.g. add negptr,ptr1; or the NEGATEDPTR could be
				//  just a USE, e.g. add reg,negptr, so that reg is overwritten and becomes a
				//  PTROFFSET. It really does not matter. The point is that we want to ignore
				//  overflow on this addition, and also on the subtraction that produced the
				//  NEGATEDPTR, so we mark the DEF in each instruction as benignly overflowing.
				op_t UseInstDefOp = DefIter->GetOp();
				CurrInst->SetDefNoOverflow(UseInstDefOp, true);
				SMPInstr *DefInst = this->GetInstFromAddr(DefAddr);
				DefInst->SetDefNoOverflow(DefOp, true);
				break;
			}
		}
	}

	return benign;
} // end of SMPFunction::IsBenignUnderflowDEF()

bool SMPFunction::HasIntErrorCallSink(op_t DefOp, int DefSSANum, size_t DefAddr, std::string &SinkString) {
	bool FoundSink = false;

	this->ResetProcessedBlocks(); // prepare for recursion through blocks
	SinkString.clear();
	SMPBasicBlock *CurrBlock = this->GetBlockFromInstAddr(DefAddr);
	assert(CurrBlock != NULL);

	FoundSink = CurrBlock->IsCriticalSink(DefOp, DefSSANum, SinkString);

	return FoundSink;
} // end of SMPFunction::HasIntErrorCallSink()

// Compute SSA form data structures across the function.
void SMPFunction::ComputeSSA(void) {
	bool DebugFlag = false;
	bool DumpFlag = false;
#if SMP_DEBUG_DATAFLOW
	DumpFlag |= (0 == strcmp("uw_frame_state_for", this->GetFuncName()));
	DebugFlag |= (0 == strcmp("uw_frame_state_for", this->GetFuncName()));
#endif

#if 1
	if (DumpFlag)
		this->Dump();
#endif
	if (DebugFlag) SMP_msg("Computing IDoms.\n");
	this->ComputeIDoms();
	if (DebugFlag) SMP_msg("Computing Dom frontiers.\n");
	this->ComputeDomFrontiers();
	if (DebugFlag) SMP_msg("Computing global names.\n");
	this->ComputeGlobalNames();
	if (DebugFlag) SMP_msg("Computing blocks defined in.\n");
	this->ComputeBlocksDefinedIn();

	if (DebugFlag) SMP_msg("Inserting Phi functions.\n");
	this->InsertPhiFunctions();
	if (DebugFlag) SMP_msg("Building dominator tree.\n");
	this->BuildDominatorTree();
	if (DebugFlag) SMP_msg("Computing SSA renumbering.\n");
	this->SSARenumber();
	list<SMPBasicBlock *>::iterator BlockIter;
	SMPBasicBlock *CurrBlock;
	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		CurrBlock = (*BlockIter);
		if (CurrBlock->FindLoopHeadsAndTails()) {
			++this->LoopCount;
		}

		if (DumpFlag) CurrBlock->Dump();

		if (DebugFlag) SMP_msg("Computing local names.\n");
		CurrBlock->SetLocalNames();
		if (DebugFlag) SMP_msg("Computing local SSA renumbering.\n");
		CurrBlock->SSALocalRenumber();
		if (DumpFlag) CurrBlock->Dump();

#if STARS_BUILD_DEF_USE_CHAINS
		if (DebugFlag) SMP_msg("Computing global chains.\n");
		CurrBlock->CreateGlobalChains();
#endif

#if 1
		if (DebugFlag) SMP_msg("Marking dead registers.\n");
		CurrBlock->MarkDeadRegs();
#endif
	}
#if SMP_DEBUG_DATAFLOW
	if (DumpFlag)
		this->Dump();
#endif

	// Once SSA numbers have been set into all DEFs, USES, and DU-chains, then
	//  the SSA numbering data structures will no longer be used and can be
	//  de-allocated.
	this->FreeSSAMemory();
	return;
} // end of SMPFunction::ComputeSSA()

// Detect which blocks are in which loops and populate FuncLoopsByBlock data structure.
void SMPFunction::DetectLoops(void) {
	list<SMPBasicBlock *>::iterator BlockIter;
	size_t LoopNumber = 0;
	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		SMPBasicBlock *CurrBlock = (*BlockIter);
		if (CurrBlock->IsLoopTailBlock()) {
			// For each loop tail block, get its loop header block number (the target
			//  block for its back edge). Then traverse the CFG upwards, recording all
			//  of the basic block numbers that lie between the loop tail and loop head,
			//  along with the tail and head.
			this->ResetProcessedBlocks();
			int TailBlockNum = CurrBlock->GetNumber();
			int HeadBlockNum = CurrBlock->GetLoopHeaderNumber();
			assert((TailBlockNum != SMP_BLOCKNUM_UNINIT) && (HeadBlockNum != SMP_BLOCKNUM_UNINIT));
			list<list<SMPBasicBlock *>::iterator> BlockWorkList;
			BlockWorkList.push_back(BlockIter);
			SMPBasicBlock *WorkBlock;
			SMPBasicBlock *PredBlock;
			list<SMPBasicBlock *>::iterator WorkIter;
			list<SMPBasicBlock *>::iterator PredIter;
			do {
				WorkIter = BlockWorkList.front();
				BlockWorkList.pop_front();
				WorkBlock = (*WorkIter);
				int WorkBlockNum = WorkBlock->GetNumber();
				assert(WorkBlockNum != SMP_BLOCKNUM_UNINIT);
				if (!(WorkBlock->IsProcessed())) {
					this->FuncLoopsByBlock[(size_t) WorkBlockNum].SetBit(LoopNumber);
					WorkBlock->SetProcessed(true);
					// Add unprocessed predecessors to the work list until we reach the loop head.
					if (WorkBlockNum != HeadBlockNum) {
						for (PredIter = WorkBlock->GetFirstPred(); PredIter != WorkBlock->GetLastPred(); ++PredIter) {
							PredBlock = (*PredIter);
							bool AlreadyProcessed = PredBlock->IsProcessed();
							if (!AlreadyProcessed) {
								BlockWorkList.push_back(PredIter);
							}
						}
					}
				}
			} while (!BlockWorkList.empty());
			++LoopNumber;
		}
	}

	return;
} // end of SMPFunction::DetectLoops()

// Find memory writes (DEFs) with possible aliases
void SMPFunction::AliasAnalysis(void) {
	// First task: Mark which memory DEFs MIGHT be aliased because an
	//  indirect memory write occurs somewhere in the DEF-USE chain.
	//  Memory DEF-USE chains with no possible aliasing can be subjected
	//  to type inference and type-based optimizing annotations, e.g. a
	//  register spill to memory followed by retrieval from spill memory
	//  followed by NUMERIC USEs should be typed as a continuous NUMERIC
	//  chain if there is no possibility of aliasing.

	// Preparatory step: For each indirect write, mark all def-use chains
	//  (maintained at the basic block level) that include the indirect
	//  write instruction. If there are no indirect writes in the function,
	//  leave all DEFs marked as unaliased and exit.
	if (!(this->HasIndirectWrites))
		return;

	list<SMPBasicBlock *>::iterator BlockIter;
	SMPBasicBlock *CurrBlock;
	vector<SMPInstr *>::iterator BlkInstIter;
	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		CurrBlock = (*BlockIter);
		for (BlkInstIter = CurrBlock->GetFirstInst(); BlkInstIter != CurrBlock->GetLastInst(); ++BlkInstIter) {
			SMPInstr *CurrInst = (*BlkInstIter);
			if (CurrInst->HasIndirectMemoryWrite()) {
#if STARS_BUILD_DEF_USE_CHAINS
				CurrBlock->MarkIndWriteChains(CurrInst->GetAddr());
#endif
				// Until we get true aliasing analysis, any indirect write
				//  is classified as may-be-aliased.
				CurrBlock->SetMaybeAliased(true);
			}
		} // end for all insts in block
	} // end for all blocks in function

	// Step one: Find only the memory DEFs to start with.
	bool FoundIndWrite = false;
	list<SMPInstr *>::iterator InstIter;
	for (InstIter = this->Instrs.begin(); InstIter != this->Instrs.end(); ++InstIter) {
		SMPInstr *CurrInst = (*InstIter);
		ea_t InstAddr = CurrInst->GetAddr();
		if (CurrInst->HasDestMemoryOperand()) {
			// Starting with the DEF instruction, traverse the control flow
			//  until we run into (A) the re-definition of the operand, including
			//  a re-definition of any of its addressing registers, or (B) an
			//  indirect write. Return false if condition A terminates the
			//  search, and true if condition B terminates the search.
			this->ResetProcessedBlocks();
			op_t MemDefOp = CurrInst->MDGetMemDefOp();
			assert(o_void != MemDefOp.type);
			set<DefOrUse, LessDefUse>::iterator CurrMemDef = CurrInst->FindDef(MemDefOp);
			assert(CurrMemDef != CurrInst->GetLastDef());
			int SSANum = CurrMemDef->GetSSANum();
			FoundIndWrite = this->FindPossibleChainAlias(CurrInst, MemDefOp, SSANum);
			if (FoundIndWrite) {
				// Mark the DEF as aliased.
				CurrMemDef = CurrInst->SetDefIndWrite(CurrMemDef->GetOp(), true);
			}
		} // end if inst has dest memory operand
	} // end for all instructions

	return;
} // end of SMPFunction::AliasAnalysis()

// Does the DefOp DEF_USE chain have an indirect mem write starting at CurrInst?
bool SMPFunction::FindPossibleChainAlias(SMPInstr *CurrInst, op_t DefOp, int SSANum) {
#if 0
	bool DebugFlag = false;
	if (0 == strcmp("sdissect", this->GetFuncName())) {
		// Next line is just a good place to set a break point.
		DebugFlag = true;
	}
#endif

	// Starting with the DEF instruction, traverse the control flow
	//  until we run into (A) the re-definition of the operand, including
	//  a re-definition of any of its addressing registers, or (B) an
	//  indirect write. Return false if condition A terminates the
	//  search, and true if condition B terminates the search.
	SMPBasicBlock *CurrBlock = CurrInst->GetBlock();
	if (!(CurrBlock->IsProcessed())) {
		CurrBlock->SetProcessed(true);
	}
	else
		return false; // block already processed

	// Proceed by cases:
	ea_t DefAddr = CurrInst->GetAddr();
	set<DefOrUse, LessDefUse>::iterator UseIter;
	vector<SMPInstr *>::iterator InstIter = CurrBlock->GetInstIterFromAddr(DefAddr);
	bool IndWriteFound, ReDef;
	++InstIter;
	// Case 1: Local name. Return the IndWrite flag for the local Def-Use
	//  chain begun by CurrInst.
	bool UseAfterIndirectWrite = CurrBlock->HasUseAfterIndWrite(DefOp, InstIter, IndWriteFound, ReDef);
	bool LiveOutFlag = CurrBlock->IsLiveOut(DefOp);
	if (CurrBlock->IsLocalName(DefOp)) {