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Merged
merged 3 commits into from
Feb 12, 2019
Merged

Optimize stack writer on deeply nested blocks, fixes #1903 #1905

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f5ea8ab
remove some old debugging
kripken Feb 7, 2019
7cb7669
optimize stack writer on deeply nested blocks, fixes #1903
kripken Feb 7, 2019
c8fd030
Merge remote-tracking branch 'origin/master' into lessdebug
kripken Feb 8, 2019
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98 changes: 55 additions & 43 deletions src/wasm-stack.h
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Original file line number Diff line number Diff line change
Expand Up @@ -359,24 +359,62 @@ void StackWriter<Mode, Parent>::visitChild(Expression* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitBlock(Block* curr) {
if (Mode == StackWriterMode::Binaryen2Stack) {
stackIR.push_back(makeStackInst(StackInst::BlockBegin, curr));
} else {
if (debug) std::cerr << "zz node: Block" << std::endl;
o << int8_t(BinaryConsts::Block);
o << binaryType(curr->type != unreachable ? curr->type : none);
}
breakStack.push_back(curr->name); // TODO: we don't need to do this in Binaryen2Stack
Index i = 0;
for (auto* child : curr->list) {
if (debug) std::cerr << " " << size_t(curr) << "\n zz Block element " << i++ << std::endl;
visitChild(child);
}
// in Stack2Binary the block ending is in the stream later on
if (Mode == StackWriterMode::Stack2Binary) {
return;
auto tilChildren = [this](Block* curr) {
if (Mode == StackWriterMode::Binaryen2Stack) {
stackIR.push_back(makeStackInst(StackInst::BlockBegin, curr));
} else {
o << int8_t(BinaryConsts::Block);
o << binaryType(curr->type != unreachable ? curr->type : none);
}
breakStack.push_back(curr->name); // TODO: we don't need to do this in Binaryen2Stack
};
auto visitChildren = [this](Block* curr, Index from) {
auto& list = curr->list;
while (from < list.size()) {
visitChild(list[from++]);
}
};
auto afterChildren = [this](Block* curr) {
// in Stack2Binary the block ending is in the stream later on
if (Mode != StackWriterMode::Stack2Binary) {
visitBlockEnd(curr);
}
};
// Handle very deeply nested blocks in the first position efficiently,
// avoiding heavy recursion.
// We only start to do this if we see it will help us (to avoid allocation
// of the vector).
// Note that Stack2Binary mode we don't need to visit children anyhow, so
// we don't need this optimization.
if (Mode != StackWriterMode::Stack2Binary) {
if (!curr->list.empty() && curr->list[0]->is<Block>()) {
std::vector<Block*> parents;
Block* child;
while (!curr->list.empty() &&
(child = curr->list[0]->dynCast<Block>())) {
parents.push_back(curr);
tilChildren(curr);
curr = child;
}
// Emit the current block, which does not have a block as
// a child in the first position.
tilChildren(curr);
visitChildren(curr, 0);
afterChildren(curr);
// Finish the later parts of all the parent blocks.
while (!parents.empty()) {
auto* parent = parents.back();
parents.pop_back();
visitChildren(parent, 1);
afterChildren(parent);
}
return;
}
}
visitBlockEnd(curr);
// Simple case of not having a nested block in the first position.
tilChildren(curr);
visitChildren(curr, 0);
afterChildren(curr);
}

template<StackWriterMode Mode, typename Parent>
Expand All @@ -403,7 +441,6 @@ void StackWriter<Mode, Parent>::visitBlockEnd(Block* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitIf(If* curr) {
if (debug) std::cerr << "zz node: If" << std::endl;
if (curr->condition->type == unreachable) {
// this if-else is unreachable because of the condition, i.e., the condition
// does not exit. So don't emit the if, but do consume the condition
Expand Down Expand Up @@ -465,7 +502,6 @@ void StackWriter<Mode, Parent>::visitIfEnd(If* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitLoop(Loop* curr) {
if (debug) std::cerr << "zz node: Loop" << std::endl;
if (Mode == StackWriterMode::Binaryen2Stack) {
stackIR.push_back(makeStackInst(StackInst::LoopBegin, curr));
} else {
Expand Down Expand Up @@ -502,7 +538,6 @@ void StackWriter<Mode, Parent>::visitLoopEnd(Loop* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitBreak(Break* curr) {
if (debug) std::cerr << "zz node: Break" << std::endl;
if (curr->value) {
visitChild(curr->value);
}
Expand All @@ -525,7 +560,6 @@ void StackWriter<Mode, Parent>::visitBreak(Break* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitSwitch(Switch* curr) {
if (debug) std::cerr << "zz node: Switch" << std::endl;
if (curr->value) {
visitChild(curr->value);
}
Expand All @@ -547,7 +581,6 @@ void StackWriter<Mode, Parent>::visitSwitch(Switch* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitCall(Call* curr) {
if (debug) std::cerr << "zz node: Call" << std::endl;
for (auto* operand : curr->operands) {
visitChild(operand);
}
Expand All @@ -561,7 +594,6 @@ void StackWriter<Mode, Parent>::visitCall(Call* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitCallIndirect(CallIndirect* curr) {
if (debug) std::cerr << "zz node: CallIndirect" << std::endl;
for (auto* operand : curr->operands) {
visitChild(operand);
}
Expand All @@ -578,14 +610,12 @@ void StackWriter<Mode, Parent>::visitCallIndirect(CallIndirect* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitGetLocal(GetLocal* curr) {
if (debug) std::cerr << "zz node: GetLocal " << (o.size() + 1) << std::endl;
if (justAddToStack(curr)) return;
o << int8_t(BinaryConsts::GetLocal) << U32LEB(mappedLocals[curr->index]);
}

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitSetLocal(SetLocal* curr) {
if (debug) std::cerr << "zz node: Set|TeeLocal" << std::endl;
visitChild(curr->value);
if (!justAddToStack(curr)) {
o << int8_t(curr->isTee() ? BinaryConsts::TeeLocal : BinaryConsts::SetLocal) << U32LEB(mappedLocals[curr->index]);
Expand All @@ -597,22 +627,19 @@ void StackWriter<Mode, Parent>::visitSetLocal(SetLocal* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitGetGlobal(GetGlobal* curr) {
if (debug) std::cerr << "zz node: GetGlobal " << (o.size() + 1) << std::endl;
if (justAddToStack(curr)) return;
o << int8_t(BinaryConsts::GetGlobal) << U32LEB(parent.getGlobalIndex(curr->name));
}

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitSetGlobal(SetGlobal* curr) {
if (debug) std::cerr << "zz node: SetGlobal" << std::endl;
visitChild(curr->value);
if (justAddToStack(curr)) return;
o << int8_t(BinaryConsts::SetGlobal) << U32LEB(parent.getGlobalIndex(curr->name));
}

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitLoad(Load* curr) {
if (debug) std::cerr << "zz node: Load" << std::endl;
visitChild(curr->ptr);
if (curr->type == unreachable) {
// don't even emit it; we don't know the right type
Expand Down Expand Up @@ -678,7 +705,6 @@ void StackWriter<Mode, Parent>::visitLoad(Load* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitStore(Store* curr) {
if (debug) std::cerr << "zz node: Store" << std::endl;
visitChild(curr->ptr);
visitChild(curr->value);
if (curr->type == unreachable) {
Expand Down Expand Up @@ -744,7 +770,6 @@ void StackWriter<Mode, Parent>::visitStore(Store* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitAtomicRMW(AtomicRMW* curr) {
if (debug) std::cerr << "zz node: AtomicRMW" << std::endl;
visitChild(curr->ptr);
// stop if the rest isn't reachable anyhow
if (curr->ptr->type == unreachable) return;
Expand Down Expand Up @@ -799,7 +824,6 @@ void StackWriter<Mode, Parent>::visitAtomicRMW(AtomicRMW* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitAtomicCmpxchg(AtomicCmpxchg* curr) {
if (debug) std::cerr << "zz node: AtomicCmpxchg" << std::endl;
visitChild(curr->ptr);
// stop if the rest isn't reachable anyhow
if (curr->ptr->type == unreachable) return;
Expand Down Expand Up @@ -840,7 +864,6 @@ void StackWriter<Mode, Parent>::visitAtomicCmpxchg(AtomicCmpxchg* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitAtomicWait(AtomicWait* curr) {
if (debug) std::cerr << "zz node: AtomicWait" << std::endl;
visitChild(curr->ptr);
// stop if the rest isn't reachable anyhow
if (curr->ptr->type == unreachable) return;
Expand Down Expand Up @@ -868,7 +891,6 @@ void StackWriter<Mode, Parent>::visitAtomicWait(AtomicWait* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitAtomicWake(AtomicWake* curr) {
if (debug) std::cerr << "zz node: AtomicWake" << std::endl;
visitChild(curr->ptr);
// stop if the rest isn't reachable anyhow
if (curr->ptr->type == unreachable) return;
Expand Down Expand Up @@ -1001,7 +1023,6 @@ void StackWriter<Mode, Parent>::visitMemoryFill(MemoryFill* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitConst(Const* curr) {
if (debug) std::cerr << "zz node: Const" << curr << " : " << curr->type << std::endl;
if (justAddToStack(curr)) return;
switch (curr->type) {
case i32: {
Expand Down Expand Up @@ -1032,12 +1053,10 @@ void StackWriter<Mode, Parent>::visitConst(Const* curr) {
case unreachable:
WASM_UNREACHABLE();
}
if (debug) std::cerr << "zz const node done.\n";
}

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitUnary(Unary* curr) {
if (debug) std::cerr << "zz node: Unary" << std::endl;
visitChild(curr->value);
if (curr->type == unreachable) {
emitExtraUnreachable();
Expand Down Expand Up @@ -1144,7 +1163,6 @@ void StackWriter<Mode, Parent>::visitUnary(Unary* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitBinary(Binary* curr) {
if (debug) std::cerr << "zz node: Binary" << std::endl;
visitChild(curr->left);
visitChild(curr->right);
if (curr->type == unreachable) {
Expand Down Expand Up @@ -1317,7 +1335,6 @@ void StackWriter<Mode, Parent>::visitBinary(Binary* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitSelect(Select* curr) {
if (debug) std::cerr << "zz node: Select" << std::endl;
visitChild(curr->ifTrue);
visitChild(curr->ifFalse);
visitChild(curr->condition);
Expand All @@ -1331,7 +1348,6 @@ void StackWriter<Mode, Parent>::visitSelect(Select* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitReturn(Return* curr) {
if (debug) std::cerr << "zz node: Return" << std::endl;
if (curr->value) {
visitChild(curr->value);
}
Expand All @@ -1342,7 +1358,6 @@ void StackWriter<Mode, Parent>::visitReturn(Return* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitHost(Host* curr) {
if (debug) std::cerr << "zz node: Host" << std::endl;
switch (curr->op) {
case CurrentMemory: {
break;
Expand All @@ -1368,21 +1383,18 @@ void StackWriter<Mode, Parent>::visitHost(Host* curr) {

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitNop(Nop* curr) {
if (debug) std::cerr << "zz node: Nop" << std::endl;
if (justAddToStack(curr)) return;
o << int8_t(BinaryConsts::Nop);
}

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitUnreachable(Unreachable* curr) {
if (debug) std::cerr << "zz node: Unreachable" << std::endl;
if (justAddToStack(curr)) return;
o << int8_t(BinaryConsts::Unreachable);
}

template<StackWriterMode Mode, typename Parent>
void StackWriter<Mode, Parent>::visitDrop(Drop* curr) {
if (debug) std::cerr << "zz node: Drop" << std::endl;
visitChild(curr->value);
if (justAddToStack(curr)) return;
o << int8_t(BinaryConsts::Drop);
Expand Down