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clc5q
committed
// 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 IndirCallFlag = (INDIR_CALL == CurrInst->GetDataFlowType());
clc5q
committed
bool TailCallFlag = CondTailCall && CurrInst->IsCondTailCall();
bool IndirJumpFlag = (INDIR_JUMP == CurrInst->GetDataFlowType());
bool LinkedToTarget = false;
for (bool ok = CurrXrefs.first_from(CurrInst->GetAddr(), XREF_ALL);
ok;
ok = CurrXrefs.next_from()) {
if ((CurrXrefs.to != 0) && (CurrXrefs.iscode)) {
// Found a code target, with its address in CurrXrefs.to
if ((CallFlag || IndirCallFlag || TailCallFlag)
clc5q
committed
&& (CurrXrefs.to != (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, list<SMPBasicBlock>::iterator>::iterator MapEntry;
MapEntry = this->InstBlockMap.find(CurrXrefs.to);
if (MapEntry == this->InstBlockMap.end()) {
msg("WARNING: addr %x not found in map for %s\n", CurrXrefs.to,
this->GetFuncName());
msg(" Referenced from %s\n", CurrInst->GetDisasm());
}
else {
list<SMPBasicBlock>::iterator 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) {
msg("Switch table link: jump at %x target at %x\n",
CurrInst->GetAddr(), CurrXrefs.to);
}
#endif
}
}
} // end for all xrefs
if (IndirJumpFlag && (!LinkedToTarget)) {
this->UnresolvedIndirectJumps = true;
msg("WARNING: Unresolved indirect jump at %x\n", CurrInst->GetAddr());
}
else if (IndirCallFlag && (!LinkedToTarget)) {
this->UnresolvedIndirectCalls = true;
msg("WARNING: Unresolved indirect call at %x\n", CurrInst->GetAddr());
} // end for all blocks
// If we have any blocks that are all no-ops and have no predecessors, remove those
// blocks. They are dead and make the CFG no longer a lattice. Any blocks that have
// no predecessors but are not all no-ops should also be removed with a different
// log message.
// NOTE: Prior to construction of hell nodes in functions with unresolved indirect jumps,
// we cannot conclude that a block with no predecessors is unreachable. Also, the block
// order might be such that removal of a block makes an already processed block
// unreachable, so we have to iterate until there are no more changes.
#if SMP_USE_SWITCH_TABLE_INFO
if (!(this->HasUnresolvedIndirectJumps())) {
#else
if (!(this->HasIndirectJumps())) {
bool changed;
do {
changed = false;
CurrBlock = this->Blocks.begin();
++CurrBlock; // don't delete the top block, no matter what.
while (CurrBlock != this->Blocks.end()) {
if (CurrBlock->GetFirstPred() == CurrBlock->GetLastPred()) {
if (CurrBlock->AllNops())
msg("Removing all nops block at %x\n", CurrBlock->GetFirstAddr());
else
msg("Removing block with no predecessors at %x\n", CurrBlock->GetFirstAddr());
// Remove this block from the predecessors list of its successors.
list<list<SMPBasicBlock>::iterator>::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<list<SMPInstr>::iterator>::iterator InstIter;
for (InstIter = CurrBlock->GetFirstInstr(); InstIter != CurrBlock->GetLastInstr(); ++InstIter) {
list<SMPInstr>::iterator DummyIter = this->Instrs.erase(*InstIter);
}
// Finally, remove the block from the blocks list.
CurrBlock = this->Blocks.erase(CurrBlock);
this->BlockCount -= 1;
changed = true;
}
else
++CurrBlock;
} // end while all blocks after the first one
} while (changed);
} // end if not indirect jumps
return;
} // end of SMPFunction::SetLinks()
// Number all basic blocks in reverse postorder (RPO) and set RPOBlocks vector to
// access them.
void SMPFunction::RPONumberBlocks(void) {
bool DebugFlag = false;
#if SMP_DEBUG_DATAFLOW
DebugFlag = (0 == strcmp("__ieee754_pow", this->GetFuncName()));
if (DebugFlag) msg("Entered RPONumberBlocks\n");
#endif
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int CurrNum = 0;
list<list<SMPBasicBlock>::iterator> WorkList;
// Number the first block with 0.
list<SMPBasicBlock>::iterator CurrBlock = this->Blocks.begin();
#if 0
if (this->RPOBlocks.capacity() <= (size_t) this->BlockCount) {
msg("Reserving %d RPOBlocks old value: %d\n", 2+this->BlockCount, this->RPOBlocks.capacity());
this->RPOBlocks.reserve(2 + this->BlockCount);
this->RPOBlocks.assign(2 + this->BlockCount, this->Blocks.end());
}
#endif
CurrBlock->SetNumber(CurrNum);
this->RPOBlocks.push_back(CurrBlock);
++CurrNum;
// Push the first block's successors onto the work list.
list<list<SMPBasicBlock>::iterator>::iterator CurrSucc = CurrBlock->GetFirstSucc();
while (CurrSucc != CurrBlock->GetLastSucc()) {
WorkList.push_back(*CurrSucc);
++CurrSucc;
}
// Use the WorkList to iterate through all blocks in the function
list<list<SMPBasicBlock>::iterator>::iterator CurrListItem = WorkList.begin();
bool change;
while (!WorkList.empty()) {
change = false;
while (CurrListItem != WorkList.end()) {
if ((*CurrListItem)->GetNumber() != SMP_BLOCKNUM_UNINIT) {
// Duplicates get pushed onto the WorkList because a block
// can be the successor of multiple other blocks. If it is
// already numbered, it is a duplicate and can be removed
// from the list.
CurrListItem = WorkList.erase(CurrListItem);
change = true;
continue;
}
if ((*CurrListItem)->AllPredecessorsNumbered()) {
// Ready to be numbered.
(*CurrListItem)->SetNumber(CurrNum);
#if 0
msg("Set RPO number %d\n", CurrNum);
if (DebugFlag && (7 == CurrNum))
this->Dump();
#endif
this->RPOBlocks.push_back(*CurrListItem);
++CurrNum;
change = true;
// Push its unnumbered successors onto the work list.
CurrSucc = (*CurrListItem)->GetFirstSucc();
while (CurrSucc != (*CurrListItem)->GetLastSucc()) {
if ((*CurrSucc)->GetNumber() == SMP_BLOCKNUM_UNINIT)
WorkList.push_back(*CurrSucc);
++CurrSucc;
}
CurrListItem = WorkList.erase(CurrListItem);
}
else {
++CurrListItem;
}
} // end while (CurrListItem != WorkList.end())
if (change) {
// Reset CurrListItem to beginning of work list for next iteration.
CurrListItem = WorkList.begin();
}
else {
// Loops can cause us to not be able to find a WorkList item that has
// all predecessors numbered. Take the WorkList item with the lowest address
// and number it so we can proceed.
CurrListItem = WorkList.begin();
ea_t LowAddr = (*CurrListItem)->GetFirstAddr();
list<list<SMPBasicBlock>::iterator>::iterator SaveItem = CurrListItem;
++CurrListItem;
while (CurrListItem != WorkList.end()) {
if (LowAddr > (*CurrListItem)->GetFirstAddr()) {
SaveItem = CurrListItem;
LowAddr = (*CurrListItem)->GetFirstAddr();
}
++CurrListItem;
}
// SaveItem should now be numbered.
(*SaveItem)->SetNumber(CurrNum);
#if SMP_DEBUG_DATAFLOW
msg("Picked LowAddr %x and set RPO number %d\n", LowAddr, CurrNum);
this->RPOBlocks.push_back(*SaveItem);
++CurrNum;
// Push its unnumbered successors onto the work list.
CurrSucc = (*SaveItem)->GetFirstSucc();
while (CurrSucc != (*SaveItem)->GetLastSucc()) {
if ((*CurrSucc)->GetNumber() == SMP_BLOCKNUM_UNINIT)
WorkList.push_back(*CurrSucc);
++CurrSucc;
}
CurrListItem = WorkList.erase(SaveItem);
CurrListItem = WorkList.begin();
} // end if (change) ... else ...
} // end while work list is nonempty
// Prior to construction of hell nodes for functions with indirect jumps, there
// could still be unnumbered blocks because they appear to be unreachable
// (no predecessors from SetLinks() because they are reached only via indirect
// jumps). We need to number these and push them on the RPOBlocks vector so
// that the vector contains all the blocks.
if (this->HasIndirectJumps()) {
for (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
if (SMP_BLOCKNUM_UNINIT == CurrBlock->GetNumber()) {
msg("Numbering indirectly reachable block at %x\n", CurrBlock->GetFirstAddr());
CurrBlock->SetNumber(CurrNum);
this->RPOBlocks.push_back(CurrBlock);
++CurrNum;
}
}
}
return;
} // end of SMPFunction::RPONumberBlocks()
// Perform live variable analysis on all blocks in the function.
// See chapter 9 of Cooper/Torczon, Engineering a Compiler, for the algorithm.
void SMPFunction::LiveVariableAnalysis(void) {
list<SMPBasicBlock>::iterator CurrBlock;
#if SMP_DEBUG_DATAFLOW
msg("LiveVariableAnalysis for %s\n", this->GetFuncName());
bool DebugFlag = (0 == strcmp("__ieee754_pow", this->GetFuncName()));
#endif
for (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
// Initialize the Killed and UpwardExposed sets for each block.
CurrBlock->InitKilledExposed();
}
bool changed;
// Iterate over each block, updating LiveOut sets until no more changes are made.
// NOTE: LVA is more efficient when computed over a reverse post-order list of blocks
// from the inverted CFG. We have an RPO list from the forward CFG, so it is just as
// good to simply iterate through the blocks in layout order.
#if 1
do {
changed = false;
for (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
changed |= CurrBlock->UpdateLiveOut();
}
} while (changed);
#else // Use reverse postorder
do {
changed = false;
for (size_t index = 0; index < this->RPOBlocks.size(); ++index) {
CurrBlock = this->RPOBlocks[index];
changed |= CurrBlock->UpdateLiveOut();
}
} while (changed);
#if SMP_USE_SSA_FNOP_MARKER
// Create DEFs in the marker instruction for all names in the LiveInSet
// of the first block. These are the names for the function that
// would otherwise look like USEs of uninitialized variables later.
// Note that the LiveVariableAnalysis work does not actually populate
// a LiveInSet for the first block, so we simulate it with its
// dataflow equation, UpExposed union (LiveOut minus VarKill).
set<op_t, LessOp>::iterator UpExposedIter, LiveOutIter;
list<SMPInstr>::iterator MarkerInst = this->Instrs.begin();
for (UpExposedIter = this->Blocks.begin()->GetFirstUpExposed();
UpExposedIter != this->Blocks.begin()->GetLastUpExposed();
++UpExposedIter) {
// Add DEF with SSANum of 0.
MarkerInst->AddDef(*UpExposedIter, UNINIT, 0);
// Add to the VarKill set.
this->Blocks.begin()->AddVarKill(*UpExposedIter);
}
for (LiveOutIter = this->Blocks.begin()->GetFirstLiveOut();
LiveOutIter != this->Blocks.begin()->GetLastLiveOut();
++LiveOutIter) {
if (!(this->Blocks.begin()->IsVarKill(*LiveOutIter))) {
// Add DEF with SSANum of 0.
MarkerInst->AddDef(*LiveOutIter, UNINIT, 0);
// Add to the VarKill set.
this->Blocks.begin()->AddVarKill(*LiveOutIter);
}
}
#endif
#if SMP_DEBUG_DATAFLOW
if (DebugFlag) msg("Exiting LiveVariableAnalysis\n");
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#endif
return;
} // end of SMPFunction::LiveVariableAnalysis()
// Return the IDom index that is the end of the intersection prefix of the Dom sets of
// the two blocks designated by the RPO numbers passed in.
// See Cooper & Torczon, "Engineering a Compiler" 1st edition figure 9.8.
int SMPFunction::IntersectDoms(int block1, int block2) const {
int finger1 = block1;
int finger2 = block2;
while (finger1 != finger2) {
while (finger1 > finger2)
finger1 = this->IDom.at(finger1);
while (finger2 > finger1)
finger2 = this->IDom.at(finger2);
}
return finger1;
} // end of SMPFunction::IntersectDoms()
// Compute immediate dominators of all blocks into IDom[] vector.
void SMPFunction::ComputeIDoms(void) {
bool DebugFlag = false;
#if SMP_DEBUG_DATAFLOW
DebugFlag = (0 == strcmp("__ieee754_pow", this->GetFuncName()));
if (DebugFlag) msg("Entered ComputeIDoms\n");
#endif
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// Initialize the IDom[] vector to uninitialized values for all blocks.
this->IDom.reserve(this->BlockCount);
this->IDom.assign(this->BlockCount, SMP_BLOCKNUM_UNINIT);
if (DebugFlag) msg("BlockCount = %d\n", this->BlockCount);
this->IDom[0] = 0; // Start block dominated only by itself
bool changed;
do {
changed = false;
for (size_t RPONum = 1; RPONum < (size_t) this->BlockCount; ++RPONum) {
if (DebugFlag) msg("RPONum %d\n", RPONum);
if (DebugFlag) {
msg("RPOBlocks vector size: %d\n", this->RPOBlocks.size());
for (size_t index = 0; index < this->RPOBlocks.size(); ++index) {
msg("RPOBlocks entry %d is %d\n", index, RPOBlocks[index]->GetNumber());
}
}
list<SMPBasicBlock>::iterator CurrBlock = this->RPOBlocks.at(RPONum);
// if (DebugFlag) msg("CurrBlock: %x\n", CurrBlock._Ptr);
list<list<SMPBasicBlock>::iterator>::iterator CurrPred;
// Initialize NewIdom to the first processed predecessor of block RPONum.
int NewIdom = SMP_BLOCKNUM_UNINIT;
for (CurrPred = CurrBlock->GetFirstPred(); CurrPred != CurrBlock->GetLastPred(); ++CurrPred) {
int PredNum = (*CurrPred)->GetNumber();
if (DebugFlag) msg("Pred: %d\n", PredNum);
// **!!** See comment below about unreachable blocks.
if (SMP_BLOCKNUM_UNINIT == PredNum)
continue;
int PredIDOM = this->IDom.at(PredNum);
if (DebugFlag) msg("Pred IDom: %d\n", PredIDOM);
if (SMP_BLOCKNUM_UNINIT != PredIDOM) {
NewIdom = PredNum;
if (NewIdom == SMP_BLOCKNUM_UNINIT) {
msg("Failure on NewIdom in ComputeIDoms for %s\n", this->GetFuncName());
if (this->HasIndirectJumps()) {
// Might be reachable only through indirect jumps.
NewIdom = 0; // make it dominated by entry block
}
}
assert(NewIdom != SMP_BLOCKNUM_UNINIT);
// Loop through all predecessors of block RPONum except block NewIdom.
// Set NewIdom to the intersection of its Dom set and the Doms set of
// each predecessor that has had its Doms set computed.
for (CurrPred = CurrBlock->GetFirstPred(); CurrPred != CurrBlock->GetLastPred(); ++CurrPred) {
int PredNum = (*CurrPred)->GetNumber();
if (DebugFlag) msg("PredNum: %d\n", PredNum);
// **!!** We could avoid failure on unreachable basic blocks
// by executing a continue statement if PredNum is -1. Long term solution
// is to prune out unreachable basic blocks.
if (PredNum == SMP_BLOCKNUM_UNINIT)
continue;
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int PredIDOM = this->IDom.at(PredNum);
if (DebugFlag) msg("PredIDOM: %d\n", PredIDOM);
if ((SMP_BLOCKNUM_UNINIT == PredIDOM) || (NewIdom == PredIDOM)) {
// Skip predecessors that have uncomputed Dom sets, or are the
// current NewIdom.
continue;
}
if (DebugFlag) msg("Old NewIdom value: %d\n", NewIdom);
NewIdom = this->IntersectDoms(PredNum, NewIdom);
if (DebugFlag) msg("New NewIdom value: %d\n", NewIdom);
}
// If NewIdom is not the value currently in vector IDom[], update the
// vector entry and set changed to true.
if (NewIdom != this->IDom.at(RPONum)) {
if (DebugFlag) msg("IDOM changed from %d to %d\n", this->IDom.at(RPONum), NewIdom);
this->IDom[RPONum] = NewIdom;
changed = true;
}
}
} while (changed);
return;
} // end of SMPFunction::ComputeIDoms()
// Compute dominance frontier sets for each block.
void SMPFunction::ComputeDomFrontiers(void) {
list<SMPBasicBlock>::iterator CurrBlock;
list<SMPBasicBlock>::iterator RunnerBlock;
for (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
// We look only at join points in the CFG, as per Cooper/Torczon chapter 9.
if (1 < CurrBlock->GetNumPreds()) { // join point; more than 1 predecessor
int runner;
list<list<SMPBasicBlock>::iterator>::iterator CurrPred;
for (CurrPred = CurrBlock->GetFirstPred(); CurrPred != CurrBlock->GetLastPred(); ++CurrPred) {
// For each predecessor, we run up the IDom[] vector and add CurrBlock to the
// DomFrontier for all blocks that are between CurrPred and IDom[CurrBlock],
// not including IDom[CurrBlock] itself.
runner = (*CurrPred)->GetNumber();
while (runner != this->IDom.at(CurrBlock->GetNumber())) {
// Cooper/Harvey/Kennedy paper does not quite agree with the later
// text by Cooper/Torczon. Text says that the start node has no IDom
// in the example on pages 462-463, but it shows an IDOM for the
// root node in Figure 9.9 of value == itself. The first edition text
// on p.463 seems correct, as the start node dominates every node and
// thus should have no dominance frontier.
if (SMP_TOP_BLOCK == runner)
break;
RunnerBlock = this->RPOBlocks.at(runner);
RunnerBlock->AddToDomFrontier(CurrBlock->GetNumber());
runner = this->IDom.at(runner);
}
} // end for all predecessors
} // end if join point
} // end for all blocks
return;
} // end of SMPFunction::ComputeDomFrontiers()
// Compute the GlobalNames set, which includes all operands that are used in more than
// one basic block. It is the union of all UpExposedSets of all blocks.
void SMPFunction::ComputeGlobalNames(void) {
set<op_t, LessOp>::iterator SetIter;
list<SMPBasicBlock>::iterator CurrBlock;
unsigned int index = 0;
if (this->Blocks.size() < 2)
return; // cannot have global names if there is only one block
bool DebugFlag = false;
#if SMP_DEBUG_DATAFLOW
DebugFlag = (0 == strcmp("__ieee754_pow", this->GetFuncName()));
#endif
for (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
for (SetIter = CurrBlock->GetFirstUpExposed(); SetIter != CurrBlock->GetLastUpExposed(); ++SetIter) {
op_t TempOp = *SetIter;
// The GlobalNames set will have the complete collection of operands that we are
// going to number in our SSA computations. We now assign an operand number
// within the op_t structure for each, so that we can index into the
// BlocksUsedIn[] vector, for example. This operand number is not to be
// confused with SSA numbers.
// We use the operand number field op_t.n for the lower 8 bits, and the offset
// fields op_t.offb:op_t.offo for the upper 16 bits. We are overwriting IDA
// values here, but operands in the data flow analysis sets should never be
// inserted back into the program anyway.
SetGlobalIndex(&TempOp, index);
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#if SMP_DEBUG_DATAFLOW
msg("Global Name: ");
PrintListOperand(TempOp);
#endif
set<op_t, LessOp>::iterator AlreadyInSet;
pair<set<op_t, LessOp>::iterator, bool> InsertResult;
InsertResult = this->GlobalNames.insert(TempOp);
if (!InsertResult.second) {
// Already in GlobalNames, so don't assign an index number.
;
#if SMP_DEBUG_DATAFLOW
msg(" already in GlobalNames.\n");
#endif
}
else {
++index;
#if SMP_DEBUG_DATAFLOW
msg(" inserted as index %d\n", ExtractGlobalIndex(TempOp));
#endif
}
} // for each upward exposed item in the current block
} // for each basic block
assert(16777215 >= this->GlobalNames.size()); // index fits in 24 bits
return;
} // end of SMPFunction::ComputeGlobalNames()
// For each item in GlobalNames, record the blocks that DEF the item.
void SMPFunction::ComputeBlocksDefinedIn(void) {
// Loop through all basic blocks and examine all DEFs. For Global DEFs, record
// the block number in BlocksDefinedIn. The VarKillSet records DEFs without
// having to examine every instruction.
list<SMPBasicBlock>::iterator CurrBlock;
this->BlocksDefinedIn.clear();
for (size_t i = 0; i < this->GlobalNames.size(); ++i) {
list<int> TempList;
this->BlocksDefinedIn.push_back(TempList);
}
#if SMP_DEBUG_DATAFLOW
msg("Number of GlobalNames: %d\n", this->GlobalNames.size());
msg("Size of BlocksDefinedIn: %d\n", this->BlocksDefinedIn.size());
#endif
for (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
set<op_t, LessOp>::iterator KillIter;
for (KillIter = CurrBlock->GetFirstVarKill(); KillIter != CurrBlock->GetLastVarKill(); ++KillIter) {
// If killed item is not a block-local item (it is global), record it.
set<op_t, LessOp>::iterator NameIter = this->GlobalNames.find(*KillIter);
if (NameIter != this->GlobalNames.end()) { // found in GlobalNames set
// We have a kill of a global name. Get index from three 8-bit fields.
unsigned int index = ExtractGlobalIndex(*NameIter);
if (index >= this->GlobalNames.size()) {
// We are about to assert false.
msg("ComputeBlocksDefinedIn: Bad index: %d limit: %d\n", index,
this->GlobalNames.size());
msg("Block number %d\n", CurrBlock->GetNumber());
msg("Killed item: ");
PrintListOperand(*KillIter);
msg("\n");
msg("This is a fatal error.\n");
}
assert(index < this->GlobalNames.size());
// index is a valid subscript for the BlocksDefinedIn vector. Push the
// current block number onto the list of blocks that define this global name.
this->BlocksDefinedIn[index].push_back(CurrBlock->GetNumber());
}
}
}
return;
} // end of SMPFunction::ComputeBlocksDefinedIn()
// Compute the phi functions at the entry point of each basic block that is a join point.
void SMPFunction::InsertPhiFunctions(void) {
set<op_t, LessOp>::iterator NameIter;
list<int> WorkList; // list of block numbers
bool DebugFlag = false;
#if SMP_DEBUG_DATAFLOW
DebugFlag = (0 == strcmp("__ieee754_pow", this->GetFuncName()));
#endif
if (DebugFlag) msg("GlobalNames size: %d\n", this->GlobalNames.size());
for (NameIter = this->GlobalNames.begin(); NameIter != this->GlobalNames.end(); ++NameIter) {
int CurrNameIndex = (int) (ExtractGlobalIndex(*NameIter));
if (DebugFlag) msg("CurrNameIndex: %d\n", CurrNameIndex);
#if 0
DebugFlag = (DebugFlag && (6 == CurrNameIndex));
#endif
// Initialize the work list to all blocks that define the current name.
WorkList.clear();
list<int>::iterator WorkIter;
for (WorkIter = this->BlocksDefinedIn.at((size_t) CurrNameIndex).begin();
WorkIter != this->BlocksDefinedIn.at((size_t) CurrNameIndex).end();
++WorkIter) {
WorkList.push_back(*WorkIter);
}
// Iterate through the work list, inserting phi functions for the current name
// into all the blocks in the dominance frontier of each work list block.
// Insert into the work list each block that had a phi function added.
while (!WorkList.empty()) {
#if SMP_DEBUG_DATAFLOW
msg("WorkList size: %d\n", WorkList.size());
list<int>::iterator WorkIter = WorkList.begin();
while (WorkIter != WorkList.end()) {
set<int>::iterator DomFrontIter;
#if SMP_DEBUG_DATAFLOW
msg("WorkIter: %d\n", *WorkIter);
#endif
if (DebugFlag && (*WorkIter > this->BlockCount)) {
msg("ERROR: WorkList block # %d out of range.\n", *WorkIter);
}
list<SMPBasicBlock>::iterator WorkBlock = this->RPOBlocks[*WorkIter];
for (DomFrontIter = WorkBlock->GetFirstDomFrontier();
DomFrontIter != WorkBlock->GetLastDomFrontier();
++DomFrontIter) {
#if SMP_DEBUG_DATAFLOW
msg("DomFront: %d\n", *DomFrontIter);
#endif
if (DebugFlag && (*DomFrontIter > this->BlockCount)) {
msg("ERROR: DomFront block # %d out of range.\n", *DomFrontIter);
}
list<SMPBasicBlock>::iterator PhiBlock = this->RPOBlocks[*DomFrontIter];
// Before inserting a phi function for the current name in *PhiBlock,
// see if the current name is LiveIn for *PhiBlock. If not, there
// is no need for the phi function. This check is what makes the SSA
// a fully pruned SSA.
if (PhiBlock->IsLiveIn(*NameIter)) {
size_t NumPreds = PhiBlock->GetNumPreds();
DefOrUse CurrRef(*NameIter);
SMPPhiFunction CurrPhi(CurrNameIndex, CurrRef);
for (size_t NumCopies = 0; NumCopies < NumPreds; ++NumCopies) {
CurrPhi.PushBack(CurrRef); // inputs to phi
}
if (PhiBlock->AddPhi(CurrPhi)) {
// If not already in Phi set, new phi function was inserted.
WorkList.push_back(PhiBlock->GetNumber());
#if SMP_DEBUG_DATAFLOW
msg("Added phi for name %d at top of block %d\n", CurrNameIndex, PhiBlock->GetNumber());
#endif
}
}
else {
if (DebugFlag) {
msg("Global %d not LiveIn for block %d\n", CurrNameIndex, PhiBlock->GetNumber());
}
}
} // end for all blocks in the dominance frontier
// Remove current block number from the work list
if (DebugFlag) {
msg("Removing block %d from work list.\n", *WorkIter);
}
WorkIter = WorkList.erase(WorkIter);
} // end for all block numbers in the work list
} // end while the work list is not empty
if (DebugFlag) msg("WorkList empty.\n");
} // end for all elements of the GlobalNames set
return;
} // end of SMPFunction::InsertPhiFunctions()
// Build the dominator tree.
void SMPFunction::BuildDominatorTree(void) {
size_t index;
// First, fill the DomTree vector with the parent numbers filled in and the child lists
// left empty.
for (index = 0; index < this->IDom.size(); ++index) {
pair<int, list<int> > DomTreeEntry;
DomTreeEntry.first = this->IDom.at(index);
DomTreeEntry.second.clear();
this->DomTree.push_back(DomTreeEntry);
}
// Now, push the children onto the appropriate lists.
for (index = 0; index < this->IDom.size(); ++index) {
// E.g. if block 5 has block 3 as a parent, then we fetch the number 3
// using the expression this->DomTree.at(index).first, which was just
// initialized in the previous loop. Then we go to DomTree entry 3 and push
// the number 5 on its child list.
int parent = this->DomTree.at(index).first;
if (parent != (int) index) // block can dominate itself, but not in DomTree!
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this->DomTree.at(parent).second.push_back((int) index);
}
return;
} // end of SMPFunction::BuildDominatorTree()
// Helper for SSA subscript renumbering: return the next SSA number for the global name
// and increment the SSACounter to prepare the next number. Push the returned number onto
// the SSAStack for the global name.
int SMPFunction::SSANewNumber(size_t GlobNameIndex) {
int Subscript = this->SSACounter.at(GlobNameIndex);
++(this->SSACounter[GlobNameIndex]);
this->SSAStack[GlobNameIndex].push_back(Subscript);
return Subscript;
} // end of SMPFunction::SSANewNumber()
// Main helper for SSA subscript renumbering. Renumber within block throughout its phi
// functions, then its DEFs and USEs, then its phi successors. Recurse then on all
// successors in the dominator tree.
void SMPFunction::SSARename(int BlockNumber) {
assert(0 <= BlockNumber);
assert(BlockNumber < this->BlockCount);
list<SMPBasicBlock>::iterator CurrBlock = this->RPOBlocks.at((size_t) BlockNumber);
bool DumpFlag = false;
#if SMP_DEBUG_DATAFLOW
DumpFlag |= (0 == strcmp("main", this->GetFuncName()));
DumpFlag |= (0 == strcmp("dohanoi", this->GetFuncName()));
DumpFlag |= (0 == strcmp("image_to_texture", this->GetFuncName()));
#endif
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if (DumpFlag) msg("Entered SSARename for block number %d\n", BlockNumber);
// For each phi function at the top of the block, rename the DEF of the phi function
// using SSANewNumber() on the global name index.
set<SMPPhiFunction, LessPhi>::iterator CurrPhi;
list<SMPPhiFunction> TempPhiList;
int GlobalNameIndex;
for (CurrPhi = CurrBlock->GetFirstPhi(); CurrPhi != CurrBlock->GetLastPhi(); ++CurrPhi) {
GlobalNameIndex = CurrPhi->GetIndex();
assert(0 <= GlobalNameIndex);
int NewSSANum = this->SSANewNumber((size_t) GlobalNameIndex);
#if 0
// g++ is a pain in the neck and won't allow changes to the set item
// through CurrPhi, which it types as a const iterator, so this next line does
// not compile in g++.
CurrPhi->SetSSADef(NewSSANum);
#else
SMPPhiFunction TempPhi = (*CurrPhi);
TempPhi.SetSSADef(NewSSANum);
TempPhiList.push_back(TempPhi);
#endif
}
// Go back through the Phi function set and replace the items that need to be updated.
// Thank you g++ for being a pain.
list<SMPPhiFunction>::iterator TempIter;
for (TempIter = TempPhiList.begin(); TempIter != TempPhiList.end(); ++TempIter) {
// Use the op_t from the first phi use, because they are all the same.
bool Erased = CurrBlock->ErasePhi(TempIter->GetPhiRef(0).GetOp());
assert(Erased);
// Now we can add back the phi function that had the DEF SSA number changed.
bool Added = CurrBlock->AddPhi(*TempIter);
assert(Added);
}
TempPhiList.clear();
if (DumpFlag) msg("Processed phi functions at top.\n");
// For each instruction in the block, rename all global USEs and then all global DEFs.
list<list<SMPInstr>::iterator>::iterator CurrInst;
for (CurrInst = CurrBlock->GetFirstInstr(); CurrInst != CurrBlock->GetLastInstr(); ++CurrInst) {
set<DefOrUse, LessDefUse>::iterator CurrUse = (*CurrInst)->GetFirstUse();
while (CurrUse != (*CurrInst)->GetLastUse()) {
// See if Use is a global name.
set<op_t, LessOp>::iterator GlobIter = this->GlobalNames.find(CurrUse->GetOp());
if (GlobIter != this->GlobalNames.end()) { // found it
unsigned int GlobIndex = ExtractGlobalIndex(*GlobIter);
if (GlobIndex > this->SSAStack.size()) {
// Get some debug info out to the log file before we crash.
msg("Bad GlobIndex: %d\n", GlobIndex);
msg("Error in function %s\n", this->GetFuncName());
exit(EXIT_FAILURE);
}
// Set the SSA number for this use to the top of stack SSA # (back())
int NewSSANum;
if (this->SSAStack.at(GlobIndex).empty()) {
// No top of stack entry to read.
#if SMP_DEBUG_UNINITIALIZED_SSA_NAMES
if (!(*CurrInst)->MDIsPopInstr() && (o_reg == GlobIter->type)) {
// POP uses the stack offset and generates spurious
// uninitialized variable messages for [esp+0].
msg("WARNING: function %s : Use of uninitialized variable: ",
this->GetFuncName());
msg(" Variable: ");
PrintListOperand(*GlobIter);
msg(" Block number: %d Address: %x Instruction: %s\n", BlockNumber,
(*CurrInst)->GetAddr(), (*CurrInst)->GetDisasm());
}
#endif
NewSSANum = SMP_SSA_UNINIT;
}
else {
NewSSANum = this->SSAStack.at(GlobIndex).back();
}
CurrUse = (*CurrInst)->SetUseSSA(CurrUse->GetOp(), NewSSANum);
} // end for all USEs
set<DefOrUse, LessDefUse>::iterator CurrDef = (*CurrInst)->GetFirstDef();
while (CurrDef != (*CurrInst)->GetLastDef()) {
// See if Def is a global name.
set<op_t, LessOp>::iterator GlobIter = this->GlobalNames.find(CurrDef->GetOp());
if (GlobIter != this->GlobalNames.end()) { // found it
unsigned int GlobIndex = ExtractGlobalIndex(*GlobIter);
// Set the SSA number for this DEF to the SSANewNumber top of stack
CurrDef = (*CurrInst)->SetDefSSA(CurrDef->GetOp(), this->SSANewNumber(GlobIndex));
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} // end for all DEFs
} // end for all instructions
if (DumpFlag) msg("Processed all instructions.\n");
// For all control flow graph (not dominator tree) successors, fill in the current
// (outgoing) SSA number in the corresponding USE slot in the phi function, for all
// global names appearing in phi functions.
list<list<SMPBasicBlock>::iterator>::iterator SuccIter;
for (SuccIter = CurrBlock->GetFirstSucc(); SuccIter != CurrBlock->GetLastSucc(); ++SuccIter) {
// What position in the Preds list of this successor is CurrBlock?
int ListPos = (*SuccIter)->GetPredPosition(BlockNumber);
assert(0 <= ListPos);
// Go through all phi functions in this successor. At ListPos position in the
// incoming arguments for that phi function, set the SSA number to the SSA number
// in the top of stack entry for the global name associated with that phi function.
set<SMPPhiFunction, LessPhi>::iterator CurrPhi;
for (CurrPhi = (*SuccIter)->GetFirstPhi(); CurrPhi != (*SuccIter)->GetLastPhi(); ++CurrPhi) {
int GlobIndex = CurrPhi->GetIndex();
int CurrSSA;
if (this->SSAStack.at(GlobIndex).empty()) {
// No top of stack entry to read.
#if SMP_DEBUG_UNINITIALIZED_SSA_NAMES
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msg("WARNING: function %s : Path to use of uninitialized variable: ",
this->GetFuncName());
msg(" Variable: ");
PrintListOperand(CurrPhi->GetAnyOp());
msg(" Block number: %d Successor block number: %d\n", BlockNumber,
(*SuccIter)->GetNumber());
#endif
CurrSSA = SMP_SSA_UNINIT;
}
else {
CurrSSA = this->SSAStack.at(GlobIndex).back(); // fetch from top of stack
}
#if 0
// g++ is a pain in the neck and won't allow changes to the set item
// through CurrPhi, which it types as a const iterator, so this next line does
// not compile in g++. C++ does not know how to distinguish between changing
// the field that ordering is based on, and other fields, so g++ has to be
// strict, I guess.
CurrPhi->SetSSARef(ListPos, CurrSSA);
#else
SMPPhiFunction TempPhi = (*CurrPhi);
TempPhi.SetSSARef(ListPos, CurrSSA);
TempPhiList.push_back(TempPhi);
if (DumpFlag && (BlockNumber >= 3) && (BlockNumber <= 4)) {
msg("BlockNumber: %d ListPos: %d\n", BlockNumber, ListPos);
}
#endif
} // end for all phi functions in successor
// Go back through the Phi function set and replace the items that need to be updated.
// Thank you g++ for being a pain.
for (TempIter = TempPhiList.begin(); TempIter != TempPhiList.end(); ++TempIter) {
if (DumpFlag && (BlockNumber >= 3) && (BlockNumber <= 4)) {
msg("Special before phi dump:\n");
set<SMPPhiFunction, LessPhi>::iterator FoundPhi;
FoundPhi = (*SuccIter)->FindPhi(TempIter->GetAnyOp());
FoundPhi->Dump();
}
// Use the op_t from the first phi use, because they are all the same.
bool Erased = (*SuccIter)->ErasePhi(TempIter->GetPhiRef(0).GetOp());
assert(Erased);
// Now we can add back the phi function that had one SSA number changed.
bool Added = (*SuccIter)->AddPhi(*TempIter);
assert(Added);
if (DumpFlag && (BlockNumber >= 3) && (BlockNumber <= 4)) {
msg("Special after phi dump:\n");
set<SMPPhiFunction, LessPhi>::iterator FoundPhi;
FoundPhi = (*SuccIter)->FindPhi(TempIter->GetAnyOp());
FoundPhi->Dump();
}
}
TempPhiList.clear();
} // end for all successors of CurrBlock
if (DumpFlag) msg("Processed successor phi functions.\n");
// For each successor in the dominator tree, recurse.
list<int>::iterator ChildIter;
for (ChildIter = this->DomTree[BlockNumber].second.begin();
ChildIter != this->DomTree[BlockNumber].second.end();
++ChildIter) {
this->SSARename(*ChildIter);
}
if (DumpFlag) msg("Finished recursion.\n");
// Pop off all SSAStack entries pushed during this block. I.e. for each global name,
// pop its SSAStack once per DEF and once per phi function in this block.
for (CurrPhi = CurrBlock->GetFirstPhi(); CurrPhi != CurrBlock->GetLastPhi(); ++CurrPhi) {
GlobalNameIndex = CurrPhi->GetIndex();
this->SSAStack.at((size_t) GlobalNameIndex).pop_back();
}
if (DumpFlag) msg("Popped off entries due to phi functions.\n");
for (CurrInst = CurrBlock->GetFirstInstr(); CurrInst != CurrBlock->GetLastInstr(); ++CurrInst) {
set<DefOrUse, LessDefUse>::iterator CurrDef;
for (CurrDef = (*CurrInst)->GetFirstDef(); CurrDef !=(*CurrInst)->GetLastDef(); ++CurrDef) {
// See if DEF is a global name.
set<op_t, LessOp>::iterator GlobIter = this->GlobalNames.find(CurrDef->GetOp());
if (GlobIter != this->GlobalNames.end()) { // found it
unsigned int GlobIndex = ExtractGlobalIndex(*GlobIter);
this->SSAStack.at((size_t) GlobIndex).pop_back();
}
} // end for all DEFs
} // end for all instructions
if (DumpFlag) msg("Popped off entries due to instructions.\n");
return;
} // end of SMPFunction::SSARename()
// Main driver of SSA subscript renumbering.
void SMPFunction::SSARenumber(void) {
if (0 >= this->GlobalNames.size())
return; // no names to renumber
// Initialize stacks and counters of SSA numbers.
size_t GlobIndex;
for (GlobIndex = 0; GlobIndex < this->GlobalNames.size(); ++GlobIndex) {
list<int> DummyList;
this->SSACounter.push_back(0);
this->SSAStack.push_back(DummyList);
}
// Recurse through the dominator tree starting with node 0.
this->SSARename(0);
} // end of SMPFunction::SSARenumber()
// Main driver for the type inference system.
void SMPFunction::InferTypes(bool FirstIter) {
// The type inference system is an iteration over four analysis steps, until
// a fixed point is reached:
// 1) Within an instruction, set types of operators based on the operator type,
// the operand types, and the instruction type category, and propagate the
// type of the SMP_ASSIGN operator to its DEF.
// 2) Propagate the type of a DEF along its SSA chain to all USEs of that SSA name.
// 3) If all USEs of an SSA name have the same type, but the DEF has no type,
// 4) If all references to a memory location have the same type, mark that memory
// location as having that type.
//
// The type inference system will mark DEFs and USEs in each instruction's DEF and USE
// sets with an inferred type. This inference USEs is not conclusive for other USEs
// outside of that instruction. For example, a pointer could be read in from memory
// and used as a pointer, then hashed using an arithmetic operation. If the arithmetic
// operation always treats its source operands as NUMERIC and produces a NUMERIC
// result, e.g. SMP_BITWISE_XOR, then the USE of that pointer is NUMERIC within
// this xor instruction. If the DEF at the beginning of the SSA chain for the pointer
// is eventually marked as POINTER, then all USEs in the chain will be marked POINTER
// as well (see step 2 above). This inconsistency along the USE chain is perfectly
// acceptable in our type system. It is important to mark the USEs according to how
// we observe them being used, because consistent USEs will propagate back up to
// the DEF in step 3 above.
bool changed;
bool UnsafeFunc = (FUNC_SAFE != this->ReturnAddrStatus);
bool DebugFlag = false;
#if SMP_DEBUG_TYPE_INFERENCE
DebugFlag |= (0 == strcmp("weightadj", this->GetFuncName()));
#endif
set<DefOrUse, LessDefUse>::iterator CurrDef;
set<DefOrUse, LessDefUse>::iterator NextDef;
list<SMPBasicBlock>::iterator CurrBlock;
if (DebugFlag) {
this->Dump();
}
// One time only: Set the types of immediate values, flags register, stack and frame
// pointers, and floating point registers.
if (FirstIter) {
for (CurrInst = this->Instrs.begin(); CurrInst != this->Instrs.end(); ++CurrInst) {
if (DebugFlag) {
msg("SetImmedTypes for inst at %x: %s\n", CurrInst->GetAddr(), CurrInst->GetDisasm());
}
CurrInst->SetImmedTypes(this->UseFP);
// Iterate until no more changes: set types in DEF and USE lists based on RTL
// operators and the instruction category, SSA DEF-USE chains, etc.
do {
changed = false;
// Step one: Infer types within instructions, context free.
// Step two, propagating DEF types to all USEs, happens within step one
// whenever a DEF type is set for the first time.
for (CurrInst = this->Instrs.begin(); CurrInst != this->Instrs.end(); ++CurrInst) {
if (DebugFlag) msg("Inferring types for %s\n", CurrInst->GetDisasm());
NewChange = CurrInst->InferTypes();
changed = (changed || NewChange);
}
} while (changed);
if (DebugFlag) msg("Finished type inference steps 1 and 2.\n");
// Step three: If all USEs of an SSA name have the same type, but the DEF has no
// type, then infer that the DEF must have the same type.
this->TypedDefs = 0;
this->UntypedDefs = 0;
clc5q
committed
this->TypedPhiDefs = 0;
this->UntypedPhiDefs = 0;
for (CurrInst = this->Instrs.begin(); CurrInst != this->Instrs.end(); ++CurrInst) {
// Find any DEF that still has type UNINIT.
CurrDef = CurrInst->GetFirstDef();
while (CurrDef != CurrInst->GetLastDef()) {
// Set erase() and insert() are needed to change types of DEFs, so
// get hold of the next iterator value now.
NextDef = CurrDef;
++NextDef;
if (UNINIT != CurrDef->GetType()) {
++(this->TypedDefs);
}
else {
++(this->UntypedDefs);
if (MDIsIndirectMemoryOpnd(DefOp, this->UseFP)
#if 0
#endif
|| ((o_reg != DefOp.type) && UnsafeFunc)) {
// Don't want to infer along DEF-USE chains for indirect
// memory accesses until we have alias analysis.
++CurrDef;
continue;
}
ea_t DefAddr = CurrInst->GetAddr();
// Call inference method based on whether it is a block-local
// name or a global name.
if (CurrInst->GetBlock()->IsLocalName(DefOp)) {
set<op_t, LessOp>::iterator NameIter;
NameIter = CurrInst->GetBlock()->FindLocalName(DefOp);
assert(CurrInst->GetBlock()->GetLastLocalName() != NameIter);
unsigned int LocIndex = ExtractGlobalIndex(*NameIter);
NewChange = CurrInst->GetBlock()->InferLocalDefType(DefOp, LocIndex, DefAddr);
if (NewChange) {
--(this->UntypedDefs);
++(this->TypedDefs);