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Instrumentation/reduce allocas #419

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Instrumentation/reduce allocas #419

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286e3d2
feat[concept]: improved debug output and omitted instrumentation of u…
lukasrothenberger Oct 17, 2023
562e501
fix: added condition to disable skipping "uninteresting" allocas
lukasrothenberger Oct 17, 2023
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80 changes: 78 additions & 2 deletions DiscoPoP/DiscoPoP.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
#define DP_VERBOSE false // prints warning messages
#define DP_hybrid_DEBUG false
#define DP_hybrid_SKIP false //todo add parameter to disable hybrid dependence analysis on demand.
#define DP_INSTRUMENT_ALL_ALLOCAS false


using namespace llvm;
Expand Down Expand Up @@ -771,9 +772,19 @@ void DiscoPoP::fillCUVariables(Region *TopRegion,
// Changed TerminatorInst to Instuction
const Instruction *TInst;
string successorBB;
if (DP_DEBUG) {
errs() << "\tfillCUVariables: start\n";
}

int counter = 0;
for (Region::block_iterator bb = TopRegion->block_begin();
bb != TopRegion->block_end(); ++bb) {

if (DP_DEBUG) {
counter++;
errs() << "\tfillCUVariables: iter: " << counter << "\n";
}

CU *lastCU = BBIDToCUIDsMap[bb->getName().str()]
.back(); // get the last CU in the basic block
// get all successor basic blocks for bb
Expand Down Expand Up @@ -825,6 +836,9 @@ void DiscoPoP::fillCUVariables(Region *TopRegion,
}
}
}
if (DP_DEBUG) {
errs() << "\tfillCUVariables: end\n";
}
}

void DiscoPoP::findStartEndLineNumbers(Node *root, int &start, int &end) {
Expand Down Expand Up @@ -2070,6 +2084,9 @@ bool DiscoPoP::runOnFunction(Function &F) {

// CUGeneration
{
if (DP_DEBUG) {
errs() << "pass DiscoPoP CU Generation: started function\n";
}
/********************* Initialize root values ***************************/
Node *root = new Node;
root->name = F.getName().str();
Expand Down Expand Up @@ -2097,6 +2114,9 @@ bool DiscoPoP::runOnFunction(Function &F) {
Variable v(it->getName().str(), rso.str(), to_string(fileID) + ":" + lid, true, true, to_string(variableType->getScalarSizeInBits()/8));
root->argumentsList.push_back(v);
}
if (DP_DEBUG) {
errs() << "\tinitialized.\n";
}
/********************* End of initialize root values
* ***************************/
LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>(F).getLoopInfo();
Expand All @@ -2111,13 +2131,24 @@ bool DiscoPoP::runOnFunction(Function &F) {
getFunctionReturnLines(TopRegion, root);

populateGlobalVariablesSet(TopRegion, globalVariablesSet);
if (DP_DEBUG) {
errs() << "\tprepared data structures.\n";
}

createCUs(TopRegion, globalVariablesSet, CUVector, BBIDToCUIDsMap, root, LI);
if (DP_DEBUG) {
errs() << "\tcreated CUs.\n";
}

fillCUVariables(TopRegion, globalVariablesSet, CUVector, BBIDToCUIDsMap);

if (DP_DEBUG) {
errs() << "\tfilled CU variables.\n";
}

fillStartEndLineNumbers(root, LI);
if (DP_DEBUG) {
errs() << "\tfilled CU start and end line numbers.\n";
}

secureStream();

Expand All @@ -2129,11 +2160,17 @@ bool DiscoPoP::runOnFunction(Function &F) {
for (auto i: CUVector) {
delete (i);
}
if (DP_DEBUG) {
errs() << "pass DiscoPoP CU Generation: finished function\n";
}
}
// CUGeneration end

// DPInstrumentation
{
if (DP_DEBUG) {
errs() << "pass DiscoPoP instrumentation: started function\n";
}
// Check loop parallelism?
if (ClCheckLoopPar) {
LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>(F).getLoopInfo();
Expand All @@ -2153,7 +2190,7 @@ bool DiscoPoP::runOnFunction(Function &F) {
}

if (DP_DEBUG) {
errs() << "pass DiscoPoP: finished function\n";
errs() << "pass DiscoPoP instrumentation: finished function\n";
}
}
// DPInstrumentation end
Expand All @@ -2173,6 +2210,7 @@ bool DiscoPoP::runOnFunction(Function &F) {

set < Value * > staticallyPredictableValues;
// Get local values (variables)
if (DP_DEBUG) errs() << "\tOmission Analysis: get local values...\n";
for (Instruction &I: F.getEntryBlock()) {
if (AllocaInst * AI = dyn_cast<AllocaInst>(&I)) {
staticallyPredictableValues.insert(AI);
Expand Down Expand Up @@ -2208,8 +2246,10 @@ bool DiscoPoP::runOnFunction(Function &F) {
}
}
}
if (DP_DEBUG) errs() << "\tOmission Analysis: get local values done\n";

// assign static memory region IDs to statically predictable values and thus dependencies
if (DP_DEBUG) errs() << "\tOmission Analysis: assign mem reg ids...\n";
unordered_map<string, pair<string, string>> staticValueNameToMemRegIDMap; // <SSA variable name>: (original variable name, statically assigned MemReg ID)
bool tmpIsGlobal;
long next_id;
Expand All @@ -2229,6 +2269,7 @@ bool DiscoPoP::runOnFunction(Function &F) {
staticMemoryRegionID = "S" + to_string(next_id);
staticValueNameToMemRegIDMap[llvmIRVarName] = pair<string, string>(originalVarName, staticMemoryRegionID);
}
if (DP_DEBUG) errs() << "\tOmission Analysis: assign mem reg ids done\n";

if (DP_hybrid_DEBUG) {
errs() << "--- Local Values ---\n";
Expand All @@ -2243,10 +2284,18 @@ bool DiscoPoP::runOnFunction(Function &F) {
map < BasicBlock * , set < string >> conditionalBBDepMap;
map < BasicBlock * , map < BasicBlock *, set < string>>> conditionalBBPairDepMap;

if (DP_DEBUG) errs() << "\tOmission Analysis: getDomTree...\n";
auto &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
if (DP_DEBUG) errs() << "\tOmission Analysis: getDomTree done.\n";
if (DP_DEBUG) errs() << "\tOmission Analysis: get InstructionCFG...\n";
InstructionCFG CFG(VNF, F);
if (DP_DEBUG) errs() << "\tOmission Analysis: get InstructionCFG done.\n";
if (DP_DEBUG) errs() << "\tOmission Analysis: get InstructionDG...\n";
InstructionDG DG(VNF, &CFG, fid);
if (DP_DEBUG) errs() << "\tOmission Analysis: get InstructionDG done.\n";


if (DP_DEBUG) errs() << "\tOmission Analysis: perform SPA dependence analysis...\n";
for (auto edge: DG.getEdges()) {
Instruction *Src = edge->getSrc()->getItem();
Instruction *Dst = edge->getDst()->getItem();
Expand Down Expand Up @@ -2277,17 +2326,21 @@ bool DiscoPoP::runOnFunction(Function &F) {
omittableInstructions.insert(Src);
omittableInstructions.insert(Dst);
}
if (DP_DEBUG) errs() << "\tOmission Analysis: perform SPA dependence analysis done.\n";

// Omit SPA instructions with no dependences
if (DP_DEBUG) errs() << "\tOmission Analysis: omit SPA instructions...\n";
for (auto node: DG.getInstructionNodes()) {
if (!isa<StoreInst>(node->getItem()) && !!isa<LoadInst>(node->getItem())) continue;
V = node->getItem()->getOperand(isa<StoreInst>(node->getItem()) ? 1 : 0);
if (!DG.getInEdges(node).size() && !DG.getOutEdges(node).size() &&
staticallyPredictableValues.find(V) != staticallyPredictableValues.end())
omittableInstructions.insert(node->getItem());
}
if (DP_DEBUG) errs() << "\tOmission Analysis: omit SPA instructions done.\n";

// Add observation of execution of single basic blocks
if (DP_DEBUG) errs() << "\tOmission Analysis: 1...\n";
for (auto pair: conditionalBBDepMap) {
// Insert call to reportbb
Instruction *insertionPoint = pair.first->getTerminator();
Expand Down Expand Up @@ -2315,8 +2368,10 @@ bool DiscoPoP::runOnFunction(Function &F) {
// ---------------------------------
++bbDepCount;
}
if (DP_DEBUG) errs() << "\tOmission Analysis: 1 done.\n";

// Add observation of in-order execution of pairs of basic blocks
if (DP_DEBUG) errs() << "\tOmission Analysis: 2...\n";
for (auto pair1: conditionalBBPairDepMap) {
// Alloca and init semaphore var for BB
auto AI = new AllocaInst(Int32, 0, "__dp_bb",
Expand Down Expand Up @@ -2356,6 +2411,7 @@ bool DiscoPoP::runOnFunction(Function &F) {
// Insert semaphore update to true
new StoreInst(ConstantInt::get(Int32, 1), AI, false, pair1.first->getTerminator());
}
if (DP_DEBUG) errs() << "\tOmission Analysis: 2 done\n";

if (DumpToDot) {
CFG.dumpToDot(fileName + "_" + string(F.getName()) + ".CFG.dot");
Expand Down Expand Up @@ -2411,6 +2467,7 @@ bool DiscoPoP::runOnFunction(Function &F) {
}

// Remove omittable instructions from profiling
if (DP_DEBUG) errs() << "\tOmission Analysis: 3...\n";
Instruction *DP_Instrumentation;
for (Instruction *I: omittableInstructions) {
if (isa<AllocaInst>(I)) {
Expand All @@ -2431,6 +2488,7 @@ bool DiscoPoP::runOnFunction(Function &F) {
}
}
}
if (DP_DEBUG) errs() << "\tOmission Analysis: 3 done.\n";

// Report statically identified dependencies

Expand Down Expand Up @@ -3313,6 +3371,24 @@ void DiscoPoP::instrumentAlloca(AllocaInst *toInstrument) {
Value *startAddr = IRB.CreatePtrToInt(toInstrument, Int64, "");
args.push_back(startAddr);

// skip uninteresting allocas
if(!DP_INSTRUMENT_ALL_ALLOCAS){
bool is_interesting = false;
if(!toInstrument->isStaticAlloca()){
is_interesting = true;
}
if(toInstrument->isArrayAllocation()){
is_interesting = true;
}
if(toInstrument->getAllocatedType()->isArrayTy()){
is_interesting = true;
}
if(!is_interesting){
return;
}
}


Value *endAddr = startAddr;
uint64_t elementSizeInBytes = toInstrument->getAllocatedType()->getScalarSizeInBits() / 8;
Value *numElements = toInstrument->getOperand(0);
Expand Down