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if (0 < RetAddrSize) {
qfprintf(AnnotFile, "%10x %6d MEMORYHOLE STACK esp + %d ReturnAddress \n",
addr, RetAddrSize, (LocalVarsSize + CalleeSavedRegsSize));
}
if (0 < CalleeSavedRegsSize) {
qfprintf(AnnotFile, "%10x %6d MEMORYHOLE STACK esp + %d CalleeSavedRegs \n",
addr, CalleeSavedRegsSize, LocalVarsSize);
if (0 < LocalVarsSize) {
unsigned long ParentReferentID = DataReferentID++;
qfprintf(AnnotFile, "%10x %6d DATAREF STACK %d esp + %d PARENT LocalFrame LOCALFRAME\n",
addr, LocalVarsSize, ParentReferentID, 0);
#if SMP_COMPUTE_STACK_GRANULARITY
if (this->AnalyzedSP && !this->CallsAlloca && (BADADDR != this->LocalVarsAllocInstr)) {
// We can only fine-grain the stack frame if we were able to analyze the stack
if (this->OutgoingArgsSize > 0) {
qfprintf(AnnotFile, "%10x %6d DATAREF STACK %d esp + %d CHILDOF %d OFFSET %d OutArgsRegion OUTARGS\n",
addr, this->OutgoingArgsSize, DataReferentID, 0, ParentReferentID, 0);
++DataReferentID;
#if SMP_DEBUG_STACK_GRANULARITY
msg("LocalVarTable of size %d for function %s\n", this->LocalVarTable.size(),
this->GetFuncName());
for (size_t i = 0; i < this->LocalVarTable.size(); ++i) {
#if SMP_DEBUG_STACK_GRANULARITY
msg("Entry %d offset %d size %d name %s\n", i, this->LocalVarTable[i].offset,
this->LocalVarTable[i].size, this->LocalVarTable[i].VarName);
// Don't emit annotations for incoming or outgoing args or anything else
// above or below the current local frame.
if ((this->LocalVarTable[i].offset >= (long) this->FuncInfo.frsize)
|| (this->LocalVarTable[i].offset < (long) this->OutgoingArgsSize))
continue;
qfprintf(AnnotFile, "%10x %6d DATAREF STACK %d esp + %d CHILDOF %d OFFSET %d LOCALVAR %s \n",
addr, this->LocalVarTable[i].size, DataReferentID,
this->LocalVarTable[i].offset, ParentReferentID,
this->LocalVarTable[i].offset, this->LocalVarTable[i].VarName);
++DataReferentID;
} // end if (this->AnalyzedSP and not Alloca .... )
} // end if (0 < LocalVarsSize)
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return;
} // end of SMPFunction::EmitStackFrameAnnotations()
// Main data flow analysis driver. Goes through the function and
// fills all objects for instructions, basic blocks, and the function
// itself.
void SMPFunction::Analyze(void) {
list<SMPInstr>::iterator FirstInBlock = this->Instrs.end();
// For starting a basic block
list<SMPInstr>::iterator LastInBlock = this->Instrs.end();
// Terminating a basic block
#if SMP_DEBUG_CONTROLFLOW
msg("Entering SMPFunction::Analyze.\n");
#endif
// Get some basic info from the FuncInfo structure.
this->Size = this->FuncInfo.endEA - this->FuncInfo.startEA;
this->UseFP = (0 != (this->FuncInfo.flags & (FUNC_FRAME | FUNC_BOTTOMBP)));
this->StaticFunc = (0 != (this->FuncInfo.flags & FUNC_STATIC));
get_func_name(this->FuncInfo.startEA, this->FuncName,
sizeof(this->FuncName) - 1);
this->BlockCount = 0;
this->AnalyzedSP = this->FuncInfo.analyzed_sp();
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#if SMP_DEBUG_CONTROLFLOW
msg("SMPFunction::Analyze: got basic info.\n");
#endif
// Cycle through all chunks that belong to the function.
func_tail_iterator_t FuncTail(&(this->FuncInfo));
size_t ChunkCounter = 0;
for (bool ChunkOK = FuncTail.main(); ChunkOK; ChunkOK = FuncTail.next()) {
const area_t &CurrChunk = FuncTail.chunk();
++ChunkCounter;
if (1 < ChunkCounter) {
this->SharedChunks = true;
#if SMP_DEBUG_CHUNKS
msg("Found tail chunk for %s at %x\n", this->FuncName, CurrChunk.startEA);
#endif
}
// 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 = SMPInstr(addr);
// Fill in the instruction data members.
#if SMP_DEBUG_CONTROLFLOW
msg("SMPFunction::Analyze: calling CurrInst::Analyze.\n");
#endif
CurrInst.Analyze();
if (SMPBinaryDebug) {
msg("Disasm: %s \n", CurrInst.GetDisasm());
}
if (this->AnalyzedSP) {
// Audit the IDA SP analysis.
sval_t sp_delta = get_spd(&(this->FuncInfo), addr);
// sp_delta is difference between current value of stack pointer
// and value of the stack pointer coming into the function. It
// is updated AFTER each instruction. Thus, it should not get back
// above zero (e.g. to +4) until after a return instruction.
if (sp_delta > 0) {
// Stack pointer has underflowed, according to IDA's analysis,
// which is probably incorrect.
this->AnalyzedSP = false;
msg("Resetting AnalyzedSP to false for %s\n", this->GetFuncName());
msg("Underflowing instruction: %s sp_delta: %d\n", CurrInst.GetDisasm(),
sp_delta);
}
}
if (CurrInst.GetDataFlowType() == INDIR_CALL)
this->IndirectCalls = true;
else if (CurrInst.GetDataFlowType() == CALL) {
set<DefOrUse, LessDefUse>::iterator CurrUse;
for (CurrUse = CurrInst.GetFirstUse(); CurrUse != CurrInst.GetLastUse(); ++CurrUse) {
optype_t OpType = CurrUse->GetOp().type;
if ((OpType == o_near) || (OpType == o_far)) {
ea_t CallTarget = CurrUse->GetOp().addr;
this->DirectCallTargets.push_back(CallTarget);
}
}
}
// Before we insert the instruction into the instruction
// list, determine if it is a jump target that does not
// follow a basic block terminator. This is the special case
// of a CASE in a SWITCH that falls through into another
// CASE, for example. The first sequence of statements
// was not terminated by a C "break;" statement, so it
// looks like straight line code, but there is an entry
// point at the beginning of the second CASE sequence and
// we have to split basic blocks at the entry point.
if ((FirstInBlock != this->Instrs.end())
&& CurrInst.IsJumpTarget()) {
#if SMP_DEBUG_CONTROLFLOW
msg("SMPFunction::Analyze: hit special jump target case.\n");
#endif
LastInBlock = --(this->Instrs.end());
SMPBasicBlock CurrBlock = SMPBasicBlock(this, FirstInBlock,
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LastInBlock);
CurrBlock.Analyze();
// If not the first chunk in the function, it is a shared
// tail chunk.
if (ChunkCounter > 1) {
CurrBlock.SetShared();
}
FirstInBlock = this->Instrs.end();
LastInBlock = this->Instrs.end();
this->Blocks.push_back(CurrBlock);
this->BlockCount += 1;
}
#if SMP_DEBUG_CONTROLFLOW
msg("SMPFunction::Analyze: putting CurrInst on list.\n");
#endif
// Insert instruction at end of list.
this->Instrs.push_back(CurrInst);
// Find basic block leaders and terminators.
if (FirstInBlock == this->Instrs.end()) {
#if SMP_DEBUG_CONTROLFLOW
msg("SMPFunction::Analyze: setting FirstInBlock.\n");
#endif
FirstInBlock = --(this->Instrs.end());
}
if (CurrInst.IsBasicBlockTerminator()) {
#if SMP_DEBUG_CONTROLFLOW
msg("SMPFunction::Analyze: found block terminator.\n");
#endif
LastInBlock = --(this->Instrs.end());
SMPBasicBlock CurrBlock = SMPBasicBlock(this, FirstInBlock, LastInBlock);
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CurrBlock.Analyze();
// If not the first chunk in the function, it is a shared
// tail chunk.
if (ChunkCounter > 1) {
CurrBlock.SetShared();
}
FirstInBlock = this->Instrs.end();
LastInBlock = this->Instrs.end();
this->Blocks.push_back(CurrBlock);
this->BlockCount += 1;
// Is the instruction a branch to a target outside the function? If
// so, this function has shared tail chunks.
if (CurrInst.IsBranchToFarChunk()) {
this->SharedChunks = true;
}
}
} // end if (isHead(InstrFlags) && isCode(InstrFlags)
} // end for (ea_t addr = FuncInfo.startEA; ... )
// Handle the special case in which a function does not terminate
// with a return instruction or any other basic block terminator.
// Sometimes IDA Pro sees a call to a NORET function and decides
// to not include the dead code after it in the function. That
// dead code includes the return instruction, so the function no
// longer includes a return instruction and terminates with a CALL.
if (FirstInBlock != this->Instrs.end()) {
LastInBlock = --(this->Instrs.end());
SMPBasicBlock CurrBlock = SMPBasicBlock(this, FirstInBlock, LastInBlock);
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CurrBlock.Analyze();
// If not the first chunk in the function, it is a shared
// tail chunk.
if (ChunkCounter > 1) {
CurrBlock.SetShared();
}
FirstInBlock = this->Instrs.end();
LastInBlock = this->Instrs.end();
this->Blocks.push_back(CurrBlock);
this->BlockCount += 1;
}
} // end for (bool ChunkOK = ...)
#if KLUDGE_VFPRINTF_FAMILY
if (0 != strstr(this->GetFuncName(), "printf")) {
this->SharedChunks = true;
msg("Kludging function %s\n", this->GetFuncName());
}
#endif
// Set up basic block links and map of instructions to blocks.
if (!(this->HasSharedChunks())) {
bool DumpFlag = false;
#if SMP_DEBUG_DATAFLOW
DumpFlag |= (0 == strcmp(".init_proc", this->GetFuncName()));
DumpFlag |= (0 == strcmp("dohanoi", this->GetFuncName()));
DumpFlag |= (0 == strcmp("_IO_new_file_write", this->GetFuncName()));
#endif
this->SetLinks();
#if SMP_COMPUTE_LVA_SSA
list<SMPInstr>::iterator CurrInst;
bool GoodRTL;
for (CurrInst = this->Instrs.begin(); CurrInst != this->Instrs.end(); ++CurrInst) {
// Build tree RTLs for the instruction.
GoodRTL = CurrInst->BuildRTL();
this->BuiltRTLs = (this->BuiltRTLs && GoodRTL);
#if SMP_DEBUG_BUILD_RTL
if (!GoodRTL) {
msg("ERROR: Cannot build RTL at %x for %s\n", CurrInst->GetAddr(), CurrInst->GetDisasm());
}
else {
msg("Built RTL at %x for %s\n", CurrInst->GetAddr(), CurrInst->GetDisasm());
#endif
if (GoodRTL)
CurrInst->SyncAllRTs();
this->RPONumberBlocks();
this->LiveVariableAnalysis();
this->ComputeSSA();
if (DumpFlag)
this->Dump();
#endif
}
#if SMP_DEBUG_CONTROLFLOW
msg("SMPFunction::Analyze: set stack frame info.\n");
#endif
// Figure out the stack frame and related info.
this->SetStackFrameInfo();
return;
} // end of SMPFunction::Analyze()
// Compute SSA form data structures across the function.
void SMPFunction::ComputeSSA(void) {
#if SMP_DEBUG_DATAFLOW
bool DumpFlag = (0 == strcmp("main", this->GetFuncName()));
DumpFlag |= (0 == strcmp("dohanoi", this->GetFuncName()));
DumpFlag |= (0 == strcmp("_init_proc", this->GetFuncName()));
#if 0
if (DumpFlag)
this->Dump();
#endif
this->ComputeIDoms();
this->ComputeDomFrontiers();
this->ComputeGlobalNames();
this->ComputeBlocksDefinedIn();
this->InsertPhiFunctions();
this->BuildDominatorTree();
list<SMPBasicBlock>::iterator CurrBlock;
for (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
CurrBlock->SetLocalNames();
CurrBlock->SSALocalRenumber();
#if 1
CurrBlock->MarkDeadRegs();
#endif
}
#if SMP_DEBUG_DATAFLOW
if (DumpFlag)
this->Dump();
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#endif
return;
} // end of SMPFunction::ComputeSSA()
// 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 CurrBlock;
#if SMP_DEBUG_DATAFLOW
msg("SetLinks called for %s\n", this->GetFuncName());
#endif
// First, set up the map of instructions to basic blocks.
for (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
list<list<SMPInstr>::iterator>::iterator CurrInst;
for (CurrInst = CurrBlock->GetFirstInstr();
CurrInst != CurrBlock->GetLastInstr();
++CurrInst) {
pair<ea_t, list<SMPBasicBlock>::iterator> MapItem((*CurrInst)->GetAddr(),CurrBlock);
InstBlockMap.insert(MapItem);
}
}
#if SMP_DEBUG_DATAFLOW
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 (CurrBlock = this->Blocks.begin(); CurrBlock != this->Blocks.end(); ++CurrBlock) {
list<SMPInstr>::iterator CurrInst = *(--(CurrBlock->GetLastInstr()));
// Last instruction in block; set successors
bool CallFlag = (CALL == CurrInst->GetDataFlowType());
xrefblk_t CurrXrefs;
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 && (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);
}
}
} // end for all xrefs
} // 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.
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);
}
// Finally, remove the block from the blocks list.
CurrBlock = this->Blocks.erase(CurrBlock);
this->BlockCount -= 1;
}
else
++CurrBlock;
}
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
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.
#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);
#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;
break;
}
}
if (NewIdom == SMP_BLOCKNUM_UNINIT)
msg("Failure on NewIdom in ComputeIDoms for %s\n", this->GetFuncName());
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;
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;
(*CurrPred)->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()
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// 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 != index) // block can dominate itself, but not in DomTree!
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());
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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_DATAFLOW
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));
} // 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