SMPFunction.cpp

} // 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;
	set<DefOrUse, LessDefUse>::iterator CurrDef;
	set<DefOrUse, LessDefUse>::iterator CurrUse;
	set<DefOrUse, LessDefUse>::iterator NextUse;
	bool DebugFlag = false;
	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 (InstIter = this->Instrs.begin(); InstIter != this->Instrs.end(); ++InstIter) {
			SMPInstr *CurrInst = (*InstIter);
			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 (DefOp.is_reg(MD_STACK_POINTER_REG) 
						|| (this->UseFP && DefOp.is_reg(MD_FRAME_POINTER_REG))) {
						// 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 (BaseOp.is_reg(MD_STACK_POINTER_REG) 
								|| (this->UseFP && BaseOp.is_reg(MD_FRAME_POINTER_REG))) {
								; // do nothing; DEF handled by case above
							}
							else {
								CurrUse = CurrInst->FindUse(BaseOp);
								if (CurrUse == CurrInst->GetLastUse()) {
									SMP_msg("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());
								}
								else {
									changed |= CurrInst->GetBlock()->PropagateLocalMetadata(BaseOp,
										DEF_METADATA_USED, CurrUse->GetSSANum());
								}
							}
						} // end if R_none != BaseReg
						if (R_none != IndexReg) {
							IndexOp.reg = MDCanonicalizeSubReg((ushort) IndexReg);
							IndexOp.dtyp = dt_dword; // canonical 32-bit width
							if (IndexOp.is_reg(R_sp) 
								|| (this->UseFP && IndexOp.is_reg(R_bp))) {
								; // do nothing; DEF handled by case above
							}
							else {
								CurrUse = CurrInst->FindUse(IndexOp);
								if (CurrUse == CurrInst->GetLastUse()) {
									SMP_msg("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());
								}
								else {
									changed |= CurrInst->GetBlock()->PropagateLocalMetadata(IndexOp,
										DEF_METADATA_USED, CurrUse->GetSSANum());
								}
							}
						} // 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) &&
						(!ReturnOp.is_reg(X86_FLAGS_REG))) {
						if (this->IsGlobalName(ReturnOp)) {
							changed |= this->PropagateGlobalMetadata(ReturnOp,
									DEF_METADATA_USED, CurrUse->GetSSANum());
						}
						else {
							changed |= CurrInst->GetBlock()->PropagateLocalMetadata(ReturnOp,
									DEF_METADATA_USED, CurrUse->GetSSANum());
						}
					}
					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) && (!UseOp.is_reg(R_sp))
						&& (!(this->UseFP && UseOp.is_reg(R_bp)))
						&& (!UseOp.is_reg(X86_FLAGS_REG))) {

						if (this->IsGlobalName(UseOp)) {
							changed |= this->PropagateGlobalMetadata(UseOp,
									DEF_METADATA_USED, CurrUse->GetSSANum());
						}
						else {
							changed |= CurrInst->GetBlock()->PropagateLocalMetadata(UseOp,
									DEF_METADATA_USED, CurrUse->GetSSANum());
						}
					} // 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) {
	bool changed = false;

	if ((0 > SSANum) || (o_void == UseOp.type))
		return false;

	// Find the DEF of UseOp with SSANum.
	bool FoundDef = false;
	list<SMPInstr *>::iterator InstIter;

	for (InstIter = this->Instrs.begin(); InstIter != this->Instrs.end(); ++InstIter) {
		SMPInstr *CurrInst = (*InstIter);
		set<DefOrUse, LessDefUse>::iterator CurrDef;
		set<DefOrUse, LessDefUse>::iterator CurrUse;
		CurrDef = CurrInst->FindDef(UseOp);
		if (CurrDef != CurrInst->GetLastDef()) {
			if (SSANum == CurrDef->GetSSANum()) {
				FoundDef = true;
				if (Status != CurrDef->GetMetadataStatus()) {
					CurrDef = CurrInst->SetDefMetadata(UseOp, Status);
					changed = (CurrDef != CurrInst->GetLastDef());

					// 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 (MDIsStackAccessOpnd(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());
								}
								else {
									changed |= CurrInst->GetBlock()->PropagateLocalMetadata(MemSrcOp,
										Status, CurrUse->GetSSANum());
								}
							} // end if stack access operand
						} // end if SafeFunc
						if (3 == CurrInst->GetOptType()) { // move inst
							break; // 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());
							break;
						}
					} // 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.
					CurrUse = CurrInst->GetFirstUse();
					while (CurrUse != CurrInst->GetLastUse()) {
						op_t UseOp = CurrUse->GetOp();
						// NOTE: **!!** To be less conservative, we
						//  should propagate less for exchange category
						//  instructions.
						if ((UseOp.type == o_reg) && (!UseOp.is_reg(R_sp))
							&& (!(this->UseFP && UseOp.is_reg(R_bp)))
							&& (!UseOp.is_reg(X86_FLAGS_REG))) {

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

	if (!FoundDef) {
		// Check the Phi functions
		list<SMPBasicBlock *>::iterator BlockIter;
		SMPBasicBlock *CurrBlock;
		for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
			set<SMPPhiFunction, LessPhi>::iterator DefPhi;
			CurrBlock = (*BlockIter);
			DefPhi = CurrBlock->FindPhi(UseOp);
			if (DefPhi != CurrBlock->GetLastPhi()) {
				if (SSANum == DefPhi->GetDefSSANum()) {
					if (Status != DefPhi->GetDefMetadata()) {
						DefPhi = CurrBlock->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);
							}
						}
					}
					FoundDef = true;
					break;
				}
			}
		} // end for all blocks
	} // end if !FoundDef

	if (!FoundDef) {
		SMP_msg("ERROR: Could not find DEF of SSANum %d for: ", SSANum);
		PrintOperand(UseOp);
		SMP_msg(" in function %s\n", this->GetFuncName());
	}

	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 CurrBlock;
	bool changed = false;

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

// 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 (DebugFlag) SMP_msg("Computing global chains.\n");
		CurrBlock->CreateGlobalChains();

#if 1
		if (DebugFlag) SMP_msg("Marking dead registers.\n");
		CurrBlock->MarkDeadRegs();
#endif
	}
#if SMP_DEBUG_DATAFLOW
	if (DumpFlag)
		this->Dump();
#endif
	// Now that we know how many loops we have, we can allocate the loops data structure.
	this->FuncLoopsByBlock.resize(this->BlockCount);
	for (size_t BlockIndex = 0; BlockIndex < this->BlockCount; ++BlockIndex) {
		this->FuncLoopsByBlock.at(BlockIndex).AllocateBits(this->LoopCount);
	}

	// 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()

// 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;
	list<SMPInstr *>::iterator InstIter;
	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		CurrBlock = (*BlockIter);
		for (InstIter = CurrBlock->GetFirstInstr();
			InstIter != CurrBlock->GetLastInstr();
			++InstIter) {

			SMPInstr *CurrInst = (*InstIter);
			if (CurrInst->HasIndirectMemoryWrite()) {
				CurrBlock->MarkIndWriteChains(CurrInst->GetAddr());
				// 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;
	for (InstIter = this->Instrs.begin(); InstIter != this->Instrs.end(); ++InstIter) {
		SMPInstr *CurrInst = (*InstIter);
		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);
				break; // Don't waste time after first alias found
			}
		} // 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();
	// Case 1: Local name. Return the IndWrite flag for the local Def-Use
	//  chain begun by CurrInst.
	if (CurrBlock->IsLocalName(DefOp)) {
		return CurrBlock->GetLocalDUChainIndWrite(DefOp, SSANum);
	}

	// Case 2: Global name.
	// Case 2A: If Def-Use chain within this block for this memory operand
	//  has its IndWrite flag set to true, then stop and return true.
	else if (CurrBlock->GetGlobalDUChainIndWrite(DefOp, DefAddr)) {
		return true;
	}

	// Case 2B: Else if Def-Use chain is not the last chain in this block
	//  for this operand, then there must be a later redefinition of the
	//  memory operand (with new SSA number assigned) later in this block.
	//  Because we did not fall into case 2A, we know there is no IndWrite
	//  within the current memory operand's chain, so we return false.
	else if (CurrBlock->IsLastGlobalChain(DefOp, DefAddr)) {
		return false;
	}

	// Case 2C: Else if current memory operand is NOT LiveOut, even though
	//  this is the last def-use chain in the block, then there is no more
	//  traversing of the control flow graph to be done. The chain has ended
	//  without encountering an IndWrite, so return false.
	else if (!(CurrBlock->IsLiveOut(DefOp))) {
		return false;
	}

	// Case 2D: We have passed all previous checks, so we must have a memory
	//  operand that reaches the end of the block without encountering an
	//  IndWrite and is LiveOut. Its may-alias status will be determined by
	//  following the control flow graph for all successor blocks and examining
	//  the def-use chains in those blocks.
	list<SMPBasicBlock *>::iterator SuccBlock;
	SuccBlock = CurrBlock->GetFirstSucc();
	bool FoundAliasedWrite = false;
	do {
		FoundAliasedWrite = this->FindChainAliasHelper(SuccBlock, DefOp);
		++SuccBlock;
	} while (!FoundAliasedWrite && (SuccBlock != CurrBlock->GetLastSucc()));

	return FoundAliasedWrite;
} // end of SMPFunction::FindPossibleChainAlias()

// recursive helper for global DU-chains that traverse CFG
bool SMPFunction::FindChainAliasHelper(list<SMPBasicBlock *>::iterator BlockIter, op_t DefOp) {
	bool DebugFlag = false;
	SMPBasicBlock *CurrBlock = (*BlockIter);
	if (0 == strcmp("mem2chunk_check", this->GetFuncName())) {
		// Next line is just a good place to set a break point.
		DebugFlag = true;
	}

	if (!(CurrBlock->IsProcessed())) {
		CurrBlock->SetProcessed(true);
	}
	else
		return false; // block already processed

	// The LVA sets can be used to decide whether it is possible that
	//  the incoming DU chain overlaps a may-alias write. We can express
	//  the decision making in a truth table:
	//
	//  Case #    LiveIn?   Killed?   AliasedWrite in block?  Action to take
	//  -------   -------   -------   ----------------------  --------------
	//    1          N          N                N             return false
	//    2          N          N                Y             return false
	//    3          N          Y                N             return false
	//    4          N          Y                Y             return false
	//    5          Y          N                N             recurse into successors
	//    6          Y          N                Y             return true
	//    7          Y          Y                N             return false
	//    8          Y          Y                Y             check location of aliased write
	//
	// In the last case, if there is an aliased write before the
	// incoming DEF is killed and after it is used, then the
	// incoming DU chain overlaps an aliased write, otherwise
	// it does not.


	// If not LiveIn, incoming DU chain does not run through this block
	//  at all, so return false.
	if (!(CurrBlock->IsLiveIn(DefOp)))
		return false;  // cases 1-4

	bool killed = CurrBlock->IsVarKill(DefOp);
	bool BlockHasAliasedWrite = CurrBlock->MaybeAliasedWrite();

	if (BlockHasAliasedWrite) {
		// If DefOp is LiveIn and is not killed, then any aliased
		//  write in the block overlaps the incoming DU chain.
		if (!killed) {
			return true;  // case 6
		}
		// If DefOp is LiveIn and is killed, then the location
		//  of the aliased write is the determining factor.
		else {
			// Incoming global DU chains get a new global DU chain
			//  built within the block with a pseudo-DefAddr of
			//  one byte before the first address of the block.
			ea_t PseudoDefAddr = CurrBlock->GetFirstAddr() - 1;
			return CurrBlock->GetGlobalDUChainIndWrite(DefOp, PseudoDefAddr); // case 8
		}
	}
	else {
		// If killed, no aliased write, then cannot overlap an aliased write.
		if (killed)
			return false; // case 7
		else {
			// Need to recurse into all successors, because we passed through
			//  the block without seeing an aliased write and without killing
			//  the DefOp.
			list<SMPBasicBlock *>::iterator SuccBlock;
			SuccBlock = CurrBlock->GetFirstSucc();
			bool FoundAliasedWrite = false;
			while (!FoundAliasedWrite && (SuccBlock != CurrBlock->GetLastSucc())) {
				FoundAliasedWrite = this->FindChainAliasHelper(SuccBlock, DefOp);
				++SuccBlock;
			};

			if (DebugFlag) {
				SMP_msg("FindChainAliasHelper is returning %d\n", FoundAliasedWrite);
			}
			return FoundAliasedWrite;
		}
	}
	assert(false); // statement should be unreachable
	return false;
} // end of SMPFunction::FindChainAliasHelper()

// Link basic blocks to their predecessors and successors, and build the map
//  of instruction addresses to basic blocks.
void SMPFunction::SetLinks(void) {
	list<SMPBasicBlock *>::iterator BlockIter;
	SMPBasicBlock *CurrBlock;
	list<SMPBasicBlock *> UnresolvedBranchWorkList;
	ea_t InstAddr;
#if SMP_DEBUG_DATAFLOW_VERBOSE
	SMP_msg("SetLinks called for %s\n", this->GetFuncName());
#endif
	// First, set up the map of instructions to basic blocks.
	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		CurrBlock = (*BlockIter);
		list<SMPInstr *>::iterator CurrInst;
		for (CurrInst = CurrBlock->GetFirstInstr();
			CurrInst != CurrBlock->GetLastInstr();
			++CurrInst) {
				InstAddr = (*CurrInst)->GetAddr();
				pair<ea_t, SMPBasicBlock *> MapItem(InstAddr, CurrBlock);
				InstBlockMap.insert(MapItem);
		}
	}

#if SMP_DEBUG_DATAFLOW_VERBOSE
	SMP_msg("SetLinks finished mapping: %s\n", this->GetFuncName());
#endif
	// Next, set successors of each basic block, also setting up the predecessors in the
	//  process.
	for (BlockIter = this->Blocks.begin(); BlockIter != this->Blocks.end(); ++BlockIter) {
		CurrBlock = (*BlockIter);
		list<SMPInstr *>::iterator InstIter = (--(CurrBlock->GetLastInstr()));
		SMPInstr *CurrInst = (*InstIter);
		InstAddr = CurrInst->GetAddr();
		bool CondTailCall = false;
		if (CurrBlock->HasReturn()) {
			if (!(CurrInst->IsCondTailCall())) {
				// We either have a return instruction or an unconditional
				//  tail call instruction. We don't want to link to the
				//  tail call target, and there is no link for a return
				continue;
			}
			else {
				// We have a conditional tail call. We don't want to
				//  link to the tail call target, but we do want fall
				//  through to the next instruction.
				CondTailCall = true;
			}
		}

		// Last instruction in block; set successors
		bool CallFlag = (CALL == CurrInst->GetDataFlowType());
		bool IndirJumpFlag = (INDIR_JUMP == CurrInst->GetDataFlowType());
		bool IndirCallFlag = (INDIR_CALL == CurrInst->GetDataFlowType());
		// NOTE: Dues to phase re-ordering, we cannot yet identify tail calls,
		//  so CondTailCall and TailCallFlag will always be false, which is harmless.
		//  SMPInstr::SetTailCall() will do a little cleanup later.
		bool TailCallFlag = CondTailCall && CurrInst->IsCondTailCall();
		SMP_xref_t CurrXrefs;
		bool LinkedToTarget = false;
		for (bool ok = CurrXrefs.SMP_first_from(CurrInst->GetAddr(), XREF_ALL);
			ok;
			ok = CurrXrefs.SMP_next_from()) {
				ea_t TargetAddr = CurrXrefs.GetTo();
				if ((TargetAddr != 0) && (CurrXrefs.GetIscode())) {
					// Found a code target, with its address in CurrXrefs.to
					if ((CallFlag || IndirCallFlag || TailCallFlag) 
						&& (TargetAddr != (CurrInst->GetAddr() + CurrInst->GetCmd().size))) {
						// A call instruction will have two targets: the fall through to the
						//  next instruction, and the called function. We want to link to the
						//  fall-through instruction, but not to the called function.
						// Some blocks end with a call just because the fall-through instruction
						//  is a jump target from elsewhere.
						continue;
					}
					map<ea_t, SMPBasicBlock *>::iterator MapEntry;
					MapEntry = this->InstBlockMap.find(TargetAddr);
					if (MapEntry == this->InstBlockMap.end()) {
						; // do nothing; probably a tail call (not yet identified)
#if 0
						SMP_msg("WARNING: addr %x not found in map for %s\n", TargetAddr,
							this->GetFuncName());
						SMP_msg(" Referenced from %s\n", CurrInst->GetDisasm());
#endif
					}
					else {
						SMPBasicBlock *Target = MapEntry->second;
						// Make target block a successor of current block.
						CurrBlock->LinkToSucc(Target);
						// Make current block a predecessor of target block.
						Target->LinkToPred(CurrBlock);
						LinkedToTarget = true;
#if SMP_USE_SWITCH_TABLE_INFO
						if (IndirJumpFlag) {
#if SMP_DEBUG_SWITCH_TABLE_INFO
							SMP_msg("Switch table link: jump at %x target at %x\n",
								CurrInst->GetAddr(), TargetAddr);
#else
							;
#endif
						}
#endif
					}
				}
		} // end for all xrefs
		if (IndirJumpFlag && (!LinkedToTarget)) {
			this->UnresolvedIndirectJumps = true;
			UnresolvedBranchWorkList.push_back(CurrBlock);
			SMP_msg("WARNING: Unresolved indirect jump at %x\n", CurrInst->GetAddr());
		}
		else if (IndirCallFlag && (!LinkedToTarget)) {
			this->UnresolvedIndirectCalls = true;
			SMP_msg("WARNING: Unresolved indirect call at %x\n", CurrInst->GetAddr());
		}
	} // end for all blocks

	// Mark all blocks that can be reached from the entry block, so we can find the unreachable ones.
	this->ResetProcessedBlocks();
	this->Blocks.front()->DepthFirstMark();
	// We have two cases: (1) Unresolved indirect branches could be targeting the unmarked blocks, making
	//  these blocks reachable, in which case we should link the unresolved branches to the unmarked blocks;
	//  or (2) there are no unresolved branches, in which case the unmarked blocks are unreachable within
	//  the function. They might be reachable from outside the function using exception handling jumps, but
	//  that still would not allow us to link them into the CFG of this function properly, so in any case we
	//  are deleting those unreachable blocks and not emitting annotations for them.
	// NOTE: An odd new gcc recursion optimization uses indirect calls within the function, so
	//  they can behave like indirect jumps. However, we don't want to link unresolved calls to unmarked blocks
	//  at this time.
	bool HellNodeCase = (!UnresolvedBranchWorkList.empty() && (this->HasUnresolvedIndirectCalls() || this->HasUnresolvedIndirectJumps()));
	bool AddedMissingLinks = false;
	bool changed;
	do {
		changed = false;
		list<SMPBasicBlock *>::iterator BlockIter = this->Blocks.begin();
		while (BlockIter != this->Blocks.end()) {
			SMPBasicBlock *CurrBlock = (*BlockIter);
			if (CurrBlock->IsProcessed()) {
				++BlockIter;
			}
			else {
				// Block cannot be reached from entry node, even after we have added links
				//  on previous loop iterations.
				if (!HellNodeCase) {
					if (CurrBlock->AllNops())
						SMP_msg("Removing all nops block at %x\n", CurrBlock->GetFirstAddr());
					else
						SMP_msg("Removing unreachable block at %x\n", CurrBlock->GetFirstAddr());
					// Remove this block from the predecessors list of its successors.
					list<SMPBasicBlock *>::iterator SuccIter;
					ea_t TempAddr = CurrBlock->GetFirstAddr();
					for (SuccIter = CurrBlock->GetFirstSucc(); SuccIter != CurrBlock->GetLastSucc(); ++SuccIter) {
						(*SuccIter)->ErasePred(TempAddr);
					}
					// Remove the unreachable instructions from the function inst list.
					list<SMPInstr *>::iterator InstIter;
					InstIter = CurrBlock->GetFirstInstr();
					ea_t FirstBadAddr = (*InstIter)->GetAddr();
					InstIter = CurrBlock->GetLastInstr();
					--InstIter; // get last real instruction
					ea_t LastBadAddr = (*InstIter)->GetAddr();
					this->EraseInstRange(FirstBadAddr, LastBadAddr);

					// Finally, remove the block from the blocks list.
					BlockIter = this->Blocks.erase(BlockIter);
					this->BlockCount -= 1;