bool CommonUniformElimPass::CommonUniformLoadElimBlock(ir::Function* func) {
bool modified = false;
for (auto& blk : *func) {
uniform2load_id_.clear();
for (auto ii = blk.begin(); ii != blk.end(); ++ii) {
if (ii->opcode() != SpvOpLoad)
continue;
uint32_t varId;
ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
if (ptrInst->opcode() != SpvOpVariable)
continue;
if (!IsUniformVar(varId))
continue;
if (!IsSamplerOrImageVar(varId))
continue;
if (HasUnsupportedDecorates(ii->result_id()))
continue;
uint32_t replId;
const auto uItr = uniform2load_id_.find(varId);
if (uItr != uniform2load_id_.end()) {
replId = uItr->second;
}
else {
uniform2load_id_[varId] = ii->result_id();
continue;
}
ReplaceAndDeleteLoad(&*ii, replId, ptrInst);
modified = true;
}
}
return modified;
}
bool CommonUniformElimPass::UniformAccessChainConvert(ir::Function* func) {
bool modified = false;
for (auto bi = func->begin(); bi != func->end(); ++bi) {
for (auto ii = bi->begin(); ii != bi->end(); ++ii) {
if (ii->opcode() != SpvOpLoad)
continue;
uint32_t varId;
ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
if (!IsNonPtrAccessChain(ptrInst->opcode()))
continue;
// Do not convert nested access chains
if (ptrInst->GetSingleWordInOperand(kAccessChainPtrIdInIdx) != varId)
continue;
if (!IsUniformVar(varId))
continue;
if (!IsConstantIndexAccessChain(ptrInst))
continue;
if (HasUnsupportedDecorates(ii->result_id()))
continue;
if (HasUnsupportedDecorates(ptrInst->result_id()))
continue;
std::vector<std::unique_ptr<ir::Instruction>> newInsts;
uint32_t replId;
GenACLoadRepl(ptrInst, &newInsts, &replId);
ReplaceAndDeleteLoad(&*ii, replId, ptrInst);
++ii;
ii = ii.InsertBefore(&newInsts);
++ii;
modified = true;
}
}
return modified;
}
bool CommonUniformElimPass::CommonExtractElimination(ir::Function* func) {
// Find all composite ids with duplicate extracts.
for (auto bi = func->begin(); bi != func->end(); ++bi) {
for (auto ii = bi->begin(); ii != bi->end(); ++ii) {
if (ii->opcode() != SpvOpCompositeExtract)
continue;
// TODO(greg-lunarg): Support multiple indices
if (ii->NumInOperands() > 2)
continue;
if (HasUnsupportedDecorates(ii->result_id()))
continue;
uint32_t compId = ii->GetSingleWordInOperand(kExtractCompositeIdInIdx);
uint32_t idx = ii->GetSingleWordInOperand(kExtractIdx0InIdx);
comp2idx2inst_[compId][idx].push_back(&*ii);
}
}
// For all defs of ids with duplicate extracts, insert new extracts
// after def, and replace and delete old extracts
bool modified = false;
for (auto bi = func->begin(); bi != func->end(); ++bi) {
for (auto ii = bi->begin(); ii != bi->end(); ++ii) {
const auto cItr = comp2idx2inst_.find(ii->result_id());
if (cItr == comp2idx2inst_.end())
continue;
for (auto idxItr : cItr->second) {
if (idxItr.second.size() < 2)
continue;
uint32_t replId = TakeNextId();
std::unique_ptr<ir::Instruction> newExtract(new ir::Instruction(*idxItr.second.front()));
newExtract->SetResultId(replId);
def_use_mgr_->AnalyzeInstDefUse(&*newExtract);
++ii;
ii = ii.InsertBefore(std::move(newExtract));
for (auto instItr : idxItr.second) {
uint32_t resId = instItr->result_id();
KillNamesAndDecorates(resId);
(void)def_use_mgr_->ReplaceAllUsesWith(resId, replId);
def_use_mgr_->KillInst(instItr);
}
modified = true;
}
}
}
return modified;
}
bool LocalSingleBlockLoadStoreElimPass::LocalSingleBlockLoadStoreElim(
Function* func) {
// Perform local store/load, load/load and store/store elimination
// on each block
bool modified = false;
std::vector<Instruction*> instructions_to_kill;
std::unordered_set<Instruction*> instructions_to_save;
for (auto bi = func->begin(); bi != func->end(); ++bi) {
var2store_.clear();
var2load_.clear();
auto next = bi->begin();
for (auto ii = next; ii != bi->end(); ii = next) {
++next;
switch (ii->opcode()) {
case SpvOpStore: {
// Verify store variable is target type
uint32_t varId;
Instruction* ptrInst = GetPtr(&*ii, &varId);
if (!IsTargetVar(varId)) continue;
if (!HasOnlySupportedRefs(varId)) continue;
// If a store to the whole variable, remember it for succeeding
// loads and stores. Otherwise forget any previous store to that
// variable.
if (ptrInst->opcode() == SpvOpVariable) {
// If a previous store to same variable, mark the store
// for deletion if not still used.
auto prev_store = var2store_.find(varId);
if (prev_store != var2store_.end() &&
instructions_to_save.count(prev_store->second) == 0) {
instructions_to_kill.push_back(prev_store->second);
modified = true;
}
bool kill_store = false;
auto li = var2load_.find(varId);
if (li != var2load_.end()) {
if (ii->GetSingleWordInOperand(kStoreValIdInIdx) ==
li->second->result_id()) {
// We are storing the same value that already exists in the
// memory location. The store does nothing.
kill_store = true;
}
}
if (!kill_store) {
var2store_[varId] = &*ii;
var2load_.erase(varId);
} else {
instructions_to_kill.push_back(&*ii);
modified = true;
}
} else {
assert(IsNonPtrAccessChain(ptrInst->opcode()));
var2store_.erase(varId);
var2load_.erase(varId);
}
} break;
case SpvOpLoad: {
// Verify store variable is target type
uint32_t varId;
Instruction* ptrInst = GetPtr(&*ii, &varId);
if (!IsTargetVar(varId)) continue;
if (!HasOnlySupportedRefs(varId)) continue;
uint32_t replId = 0;
if (ptrInst->opcode() == SpvOpVariable) {
// If a load from a variable, look for a previous store or
// load from that variable and use its value.
auto si = var2store_.find(varId);
if (si != var2store_.end()) {
replId = si->second->GetSingleWordInOperand(kStoreValIdInIdx);
} else {
auto li = var2load_.find(varId);
if (li != var2load_.end()) {
replId = li->second->result_id();
}
}
} else {
// If a partial load of a previously seen store, remember
// not to delete the store.
auto si = var2store_.find(varId);
if (si != var2store_.end()) instructions_to_save.insert(si->second);
}
if (replId != 0) {
// replace load's result id and delete load
context()->KillNamesAndDecorates(&*ii);
context()->ReplaceAllUsesWith(ii->result_id(), replId);
instructions_to_kill.push_back(&*ii);
modified = true;
} else {
if (ptrInst->opcode() == SpvOpVariable)
var2load_[varId] = &*ii; // register load
}
} break;
case SpvOpFunctionCall: {
// Conservatively assume all locals are redefined for now.
// TODO(): Handle more optimally
var2store_.clear();
var2load_.clear();
} break;
default:
break;
}
}
}
for (Instruction* inst : instructions_to_kill) {
context()->KillInst(inst);
}
return modified;
}
bool CommonUniformElimPass::CommonUniformLoadElimination(ir::Function* func) {
// Process all blocks in structured order. This is just one way (the
// simplest?) to keep track of the most recent block outside of control
// flow, used to copy common instructions, guaranteed to dominate all
// following load sites.
std::list<ir::BasicBlock*> structuredOrder;
ComputeStructuredOrder(func, &structuredOrder);
uniform2load_id_.clear();
bool modified = false;
// Find insertion point in first block to copy non-dominating loads.
auto insertItr = func->begin()->begin();
while (insertItr->opcode() == SpvOpVariable ||
insertItr->opcode() == SpvOpNop)
++insertItr;
uint32_t mergeBlockId = 0;
for (auto bi = structuredOrder.begin(); bi != structuredOrder.end(); ++bi) {
ir::BasicBlock* bp = *bi;
// Check if we are exiting outermost control construct. If so, remember
// new load insertion point. Trying to keep register pressure down.
if (mergeBlockId == bp->id()) {
mergeBlockId = 0;
insertItr = bp->begin();
}
for (auto ii = bp->begin(); ii != bp->end(); ++ii) {
if (ii->opcode() != SpvOpLoad)
continue;
uint32_t varId;
ir::Instruction* ptrInst = GetPtr(&*ii, &varId);
if (ptrInst->opcode() != SpvOpVariable)
continue;
if (!IsUniformVar(varId))
continue;
if (IsSamplerOrImageVar(varId))
continue;
if (HasUnsupportedDecorates(ii->result_id()))
continue;
uint32_t replId;
const auto uItr = uniform2load_id_.find(varId);
if (uItr != uniform2load_id_.end()) {
replId = uItr->second;
}
else {
if (mergeBlockId == 0) {
// Load is in dominating block; just remember it
uniform2load_id_[varId] = ii->result_id();
continue;
}
else {
// Copy load into most recent dominating block and remember it
replId = TakeNextId();
std::unique_ptr<ir::Instruction> newLoad(new ir::Instruction(SpvOpLoad,
ii->type_id(), replId, {{spv_operand_type_t::SPV_OPERAND_TYPE_ID, {varId}}}));
def_use_mgr_->AnalyzeInstDefUse(&*newLoad);
insertItr = insertItr.InsertBefore(std::move(newLoad));
++insertItr;
uniform2load_id_[varId] = replId;
}
}
ReplaceAndDeleteLoad(&*ii, replId, ptrInst);
modified = true;
}
// If we are outside of any control construct and entering one, remember
// the id of the merge block
if (mergeBlockId == 0) {
uint32_t dummy;
mergeBlockId = MergeBlockIdIfAny(*bp, &dummy);
}
}
return modified;
}
bool
TaintAnalysis::transfer(const Function& func, const DataflowNode& node_, NodeState& state, const std::vector<Lattice*>& dfInfo) {
static size_t ncalls = 0;
if (debug) {
*debug <<"TaintAnalysis::transfer-" <<++ncalls <<"(func=" <<func.get_name() <<",\n"
<<" node={" <<StringUtility::makeOneLine(node_.toString()) <<"},\n"
<<" state={" <<state.str(this, " ") <<",\n"
<<" dfInfo[" <<dfInfo.size() <<"]={...})\n";
}
SgNode *node = node_.getNode();
assert(!dfInfo.empty());
FiniteVarsExprsProductLattice *prodLat = dynamic_cast<FiniteVarsExprsProductLattice*>(dfInfo.front());
bool modified = magic_tainted(node, prodLat); // some values are automatically tainted based on their name
// Process AST nodes that transfer taintedness. Most of these operations have one or more inputs from which a result
// is always calculated the same way. So we just gather up the inputs and do the calculation at the very end of this
// function. The other operations are handled individually within their "if" bodies.
TaintLattice *result = NULL; // result pointer into the taint lattice
std::vector<TaintLattice*> inputs; // input pointers into the taint lattice
if (isSgAssignInitializer(node)) {
// as in "int a = b"
SgAssignInitializer *xop = isSgAssignInitializer(node);
TaintLattice *in1 = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(SgExpr2Var(xop->get_operand())));
inputs.push_back(in1);
} else if (isSgAggregateInitializer(node)) {
// as in "int a[1] = {b}"
SgAggregateInitializer *xop = isSgAggregateInitializer(node);
const SgExpressionPtrList &exprs = xop->get_initializers()->get_expressions();
for (size_t i=0; i<exprs.size(); ++i) {
varID in_id = SgExpr2Var(exprs[i]);
TaintLattice *in = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(in_id));
inputs.push_back(in);
}
} else if (isSgInitializedName(node)) {
SgInitializedName *xop = isSgInitializedName(node);
if (xop->get_initializer()) {
varID in1_id = SgExpr2Var(xop->get_initializer());
TaintLattice *in1 = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(in1_id));
inputs.push_back(in1);
}
} else if (isSgValueExp(node)) {
// numeric and character constants
SgValueExp *xop = isSgValueExp(node);
result = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(SgExpr2Var(xop)));
if (result)
modified = result->set_vertex(TaintLattice::VERTEX_UNTAINTED);
} else if (isSgAddressOfOp(node)) {
// as in "&x". The result taintedness has nothing to do with the value in x.
/*void*/
} else if (isSgBinaryOp(node)) {
// as in "a + b"
SgBinaryOp *xop = isSgBinaryOp(node);
varID in1_id = SgExpr2Var(isSgExpression(xop->get_lhs_operand()));
TaintLattice *in1 = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(in1_id));
inputs.push_back(in1);
varID in2_id = SgExpr2Var(isSgExpression(xop->get_rhs_operand()));
TaintLattice *in2 = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(in2_id));
inputs.push_back(in2);
if (isSgAssignOp(node)) { // copy the rhs lattice to the lhs lattice (as well as the entire '=' expression result)
assert(in1 && in2);
modified = in1->meetUpdate(in2);
}
} else if (isSgUnaryOp(node)) {
// as in "-a"
SgUnaryOp *xop = isSgUnaryOp(node);
varID in1_id = SgExpr2Var(xop->get_operand());
TaintLattice *in1 = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(in1_id));
inputs.push_back(in1);
} else if (isSgReturnStmt(node)) {
// as in "return a". The result will always be dead, so we're just doing this to get some debugging output. Most
// of our test inputs are functions, and the test examines the function's returned taintedness.
SgReturnStmt *xop = isSgReturnStmt(node);
varID in1_id = SgExpr2Var(xop->get_expression());
TaintLattice *in1 = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(in1_id));
inputs.push_back(in1);
}
// Update the result lattice (unless dead) with the inputs (unless dead) by using the meedUpdate() method. All this
// means is that the new result will be the maximum of the old result and all inputs, where "maximum" is defined such
// that "tainted" is greater than "untainted" (and both of them are greater than bottom/unknown).
for (size_t i=0; i<inputs.size(); ++i)
if (debug)
*debug <<"TaintAnalysis::transfer: input " <<(i+1) <<" is " <<lattice_info(inputs[i]) <<"\n";
if (!result && varID::isValidVarExp(node)) {
varID result_id(node); // NOTE: constructor doesn't handle all SgExpression nodes, thus the next "if"
result = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(result_id));
}
if (!result && isSgExpression(node)) {
varID result_id = SgExpr2Var(isSgExpression(node));
result = dynamic_cast<TaintLattice*>(prodLat->getVarLattice(result_id));
}
if (result) {
for (size_t i=0; i<inputs.size(); ++i) {
if (inputs[i])
modified = result->meetUpdate(inputs[i]) || modified;
}
}
if (debug)
*debug <<"TaintAnalysis::transfer: result is " <<lattice_info(result) <<(modified?" (modified)":" (not modified)") <<"\n";
return modified;
}
