void FunctionSignatureTransform::ArgumentExplosionFinalizeOptimizedFunction() {
SILBasicBlock *BB = &*NewF->begin();
SILBuilder Builder(BB->begin());
Builder.setCurrentDebugScope(BB->getParent()->getDebugScope());
unsigned TotalArgIndex = 0;
for (ArgumentDescriptor &AD : ArgumentDescList) {
// Simply continue if do not explode.
if (!AD.Explode) {
AIM[TotalArgIndex] = AD.Index;
TotalArgIndex ++;
continue;
}
// OK, we need to explode this argument.
unsigned ArgOffset = ++TotalArgIndex;
unsigned OldArgIndex = ArgOffset - 1;
llvm::SmallVector<SILValue, 8> LeafValues;
// We do this in the same order as leaf types since ProjTree expects that the
// order of leaf values matches the order of leaf types.
llvm::SmallVector<const ProjectionTreeNode*, 8> LeafNodes;
AD.ProjTree.getLeafNodes(LeafNodes);
for (auto *Node : LeafNodes) {
auto OwnershipKind = *AD.getTransformedOwnershipKind(Node->getType());
LeafValues.push_back(BB->insertFunctionArgument(
ArgOffset++, Node->getType(), OwnershipKind,
BB->getArgument(OldArgIndex)->getDecl()));
AIM[TotalArgIndex - 1] = AD.Index;
TotalArgIndex ++;
}
// Then go through the projection tree constructing aggregates and replacing
// uses.
AD.ProjTree.replaceValueUsesWithLeafUses(Builder, BB->getParent()->getLocation(),
LeafValues);
// We ignored debugvalue uses when we constructed the new arguments, in order
// to preserve as much information as possible, we construct a new value for
// OrigArg from the leaf values and use that in place of the OrigArg.
SILValue NewOrigArgValue = AD.ProjTree.computeExplodedArgumentValue(Builder,
BB->getParent()->getLocation(),
LeafValues);
// Replace all uses of the original arg with the new value.
SILArgument *OrigArg = BB->getArgument(OldArgIndex);
OrigArg->replaceAllUsesWith(NewOrigArgValue);
// Now erase the old argument since it does not have any uses. We also
// decrement ArgOffset since we have one less argument now.
BB->eraseArgument(OldArgIndex);
TotalArgIndex --;
}
}
unsigned ArgumentDescriptor::updateOptimizedBBArgs(SILBuilder &Builder,
SILBasicBlock *BB,
unsigned ArgOffset) {
// If this argument is completely dead, delete this argument and return
// ArgOffset.
if (IsDead) {
// If we have a callee release and we are dead, set the callee release's
// operand to undef. We do not need it to have the argument anymore, but we
// do need the instruction to be non-null.
//
// TODO: This should not be necessary.
if (CalleeRelease) {
SILType CalleeReleaseTy = CalleeRelease->getOperand(0)->getType();
CalleeRelease->setOperand(
0, SILUndef::get(CalleeReleaseTy, Builder.getModule()));
// TODO: Currently we cannot mark arguments as dead if they are released
// in a throw block. But as soon as we can do this, we have to handle
// CalleeReleaseInThrowBlock as well.
assert(!CalleeReleaseInThrowBlock &&
"released arg in throw block cannot be dead");
}
// We should be able to recursively delete all of the remaining
// instructions.
SILArgument *Arg = BB->getBBArg(ArgOffset);
eraseUsesOfValue(Arg);
BB->eraseBBArg(ArgOffset);
return ArgOffset;
}
// If this argument is not dead and we did not perform SROA, increment the
// offset and return.
if (!shouldExplode()) {
return ArgOffset + 1;
}
// Create values for the leaf types.
llvm::SmallVector<SILValue, 8> LeafValues;
// Create a reference to the old arg offset and increment arg offset so we can
// create the new arguments.
unsigned OldArgOffset = ArgOffset++;
// We do this in the same order as leaf types since ProjTree expects that the
// order of leaf values matches the order of leaf types.
{
llvm::SmallVector<SILType, 8> LeafTypes;
ProjTree.getLeafTypes(LeafTypes);
for (auto Ty : LeafTypes) {
LeafValues.push_back(BB->insertBBArg(
ArgOffset++, Ty, BB->getBBArg(OldArgOffset)->getDecl()));
}
}
// Then go through the projection tree constructing aggregates and replacing
// uses.
//
// TODO: What is the right location to use here?
ProjTree.replaceValueUsesWithLeafUses(Builder, BB->getParent()->getLocation(),
LeafValues);
// Replace all uses of the original arg with undef so it does not have any
// uses.
SILArgument *OrigArg = BB->getBBArg(OldArgOffset);
OrigArg->replaceAllUsesWith(SILUndef::get(OrigArg->getType(), BB->getModule()));
// Now erase the old argument since it does not have any uses. We also
// decrement ArgOffset since we have one less argument now.
BB->eraseBBArg(OldArgOffset);
--ArgOffset;
return ArgOffset;
}
unsigned ArgumentDescriptor::updateOptimizedBBArgs(SILBuilder &Builder,
SILBasicBlock *BB,
unsigned ArgOffset) {
// If this argument is completely dead, delete this argument and return
// ArgOffset.
if (IsDead) {
// If we have a callee release and we are dead, set the callee release's
// operand to undef. We do not need it to have the argument anymore, but we
// do need the instruction to be non-null.
//
// TODO: This should not be necessary.
for (auto &X : CalleeRelease) {
SILType CalleeReleaseTy = X->getOperand(0)->getType();
X->setOperand(
0, SILUndef::get(CalleeReleaseTy, Builder.getModule()));
}
// We should be able to recursively delete all of the remaining
// instructions.
SILArgument *Arg = BB->getBBArg(ArgOffset);
eraseUsesOfValue(Arg);
BB->eraseBBArg(ArgOffset);
return ArgOffset;
}
// If this argument is not dead and we did not perform SROA, increment the
// offset and return.
if (!shouldExplode()) {
return ArgOffset + 1;
}
// Create values for the leaf types.
llvm::SmallVector<SILValue, 8> LeafValues;
// Create a reference to the old arg offset and increment arg offset so we can
// create the new arguments.
unsigned OldArgOffset = ArgOffset++;
// We do this in the same order as leaf types since ProjTree expects that the
// order of leaf values matches the order of leaf types.
{
llvm::SmallVector<SILType, 8> LeafTypes;
ProjTree.getLeafTypes(LeafTypes);
for (auto Ty : LeafTypes) {
LeafValues.push_back(BB->insertBBArg(
ArgOffset++, Ty, BB->getBBArg(OldArgOffset)->getDecl()));
}
}
// Then go through the projection tree constructing aggregates and replacing
// uses.
//
// TODO: What is the right location to use here?
ProjTree.replaceValueUsesWithLeafUses(Builder, BB->getParent()->getLocation(),
LeafValues);
// We ignored debugvalue uses when we constructed the new arguments, in order
// to preserve as much information as possible, we construct a new value for
// OrigArg from the leaf values and use that in place of the OrigArg.
SILValue NewOrigArgValue = ProjTree.computeExplodedArgumentValue(Builder,
BB->getParent()->getLocation(),
LeafValues);
// Replace all uses of the original arg with the new value.
SILArgument *OrigArg = BB->getBBArg(OldArgOffset);
OrigArg->replaceAllUsesWith(NewOrigArgValue);
// Now erase the old argument since it does not have any uses. We also
// decrement ArgOffset since we have one less argument now.
BB->eraseBBArg(OldArgOffset);
--ArgOffset;
return ArgOffset;
}
/// \brief Propagate/remove basic block input values when all predecessors
/// supply the same arguments.
static void propagateBasicBlockArgs(SILBasicBlock &BB) {
// This functions would simplify the code as following:
//
// bb0:
// br bb2(%1 : $Builtin.Int1, %2 : $Builtin.Int1)
// bb1:
// br bb2(%1 : $Builtin.Int1, %2 : $Builtin.Int1)
// bb2(%3 : $Builtin.Int1, %4 : $Builtin.Int1):
// use(%3 : $Builtin.Int1)
// use(%4 : $Builtin.Int1)
// =>
// bb0:
// br bb2
// bb1:
// br bb2
// bb2:
// use(%1 : $Builtin.Int1)
// use(%2 : $Builtin.Int1)
// If there are no predecessors or no arguments, there is nothing to do.
if (BB.pred_empty() || BB.bbarg_empty())
return;
// Check if all the predecessors supply the same arguments to the BB.
SmallVector<SILValue, 4> Args;
bool checkArgs = false;
for (SILBasicBlock::pred_iterator PI = BB.pred_begin(), PE = BB.pred_end();
PI != PE; ++PI) {
SILBasicBlock *PredB = *PI;
// We are only simplifying cases where all predecessors are
// unconditional branch instructions.
if (!isa<BranchInst>(PredB->getTerminator()))
return;
BranchInst *BI = cast<BranchInst>(PredB->getTerminator());
unsigned Idx = 0;
assert(!BI->getArgs().empty());
for (OperandValueArrayRef::iterator AI = BI->getArgs().begin(),
AE = BI->getArgs().end();
AI != AE; ++AI, ++Idx) {
// When processing the first predecessor, record the arguments.
if (!checkArgs)
Args.push_back(*AI);
else
// On each subsequent predecessor, check the arguments.
if (Args[Idx] != *AI)
return;
}
// After the first branch is processed, the arguments vector is populated.
assert(Args.size() > 0);
checkArgs = true;
}
// If we've reached this point, the optimization is valid, so optimize.
// We know that the incoming arguments from all predecessors are the same,
// so just use them directly and remove the basic block parameters.
// Drop the arguments from the branch instructions by creating a new branch
// instruction and deleting the old one.
llvm::SmallVector<SILInstruction*, 32> ToBeDeleted;
for (SILBasicBlock::pred_iterator PI = BB.pred_begin(), PE = BB.pred_end();
PI != PE; ++PI) {
SILBasicBlock *PredB = *PI;
BranchInst *BI = cast<BranchInst>(PredB->getTerminator());
SILBuilderWithScope Bldr(PredB, BI);
Bldr.createBranch(BI->getLoc(), BI->getDestBB());
ToBeDeleted.push_back(BI);
}
// Drop the parameters from basic blocks and replace all uses with the passed
// in arguments.
unsigned Idx = 0;
for (SILBasicBlock::bbarg_iterator AI = BB.bbarg_begin(),
AE = BB.bbarg_end();
AI != AE; ++AI, ++Idx) {
// FIXME: These could be further propagatable now, we might want to move
// this to CCP and trigger another round of copy propagation.
SILArgument *Arg = *AI;
// We were able to fold, so all users should use the new folded value.
Arg->replaceAllUsesWith(Args[Idx]);
NumBasicBlockArgsPropagated++;
}
// Remove args from the block.
BB.dropAllBBArgs();
// The old branch instructions are no longer used, erase them.
recursivelyDeleteTriviallyDeadInstructions(ToBeDeleted, true);
NumInstructionsRemoved += ToBeDeleted.size();
}