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Performance optimizations for Type #2733

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Merged
merged 5 commits into from
Apr 9, 2020
Merged

Performance optimizations for Type #2733

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6766905
Performance optimizations for Type
tlively Apr 8, 2020
86516e6
Update constants
tlively Apr 8, 2020
de4a754
Remove UNKONWN_SIZE
tlively Apr 9, 2020
e3ab245
Remove extra parens
tlively Apr 9, 2020
6fb1827
reformat
tlively Apr 9, 2020
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10 changes: 7 additions & 3 deletions src/wasm-type.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,11 @@
namespace wasm {

class Type {
uint32_t id;
// enough for the limit of 1000 function arguments
static constexpr unsigned SIZE_BITS = 10;
static constexpr unsigned ID_BITS = 32 - SIZE_BITS;
unsigned id : ID_BITS;
unsigned _size : SIZE_BITS;
void init(const std::vector<Type>&);

public:
Expand All @@ -50,10 +54,10 @@ class Type {
Type() = default;

// ValueType can be implicitly upgraded to Type
constexpr Type(ValueType id) : id(id){};
constexpr Type(ValueType id) : id(id), _size(id == none ? 0 : 1){};

// But converting raw uint32_t is more dangerous, so make it explicit
constexpr explicit Type(uint32_t id) : id(id){};
explicit Type(uint32_t id);

// Construct from lists of elementary types
Type(std::initializer_list<Type> types);
Expand Down
69 changes: 46 additions & 23 deletions src/wasm/wasm-type.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,11 @@ void Type::init(const std::vector<Type>& types) {
}
#endif

if (types.size() >= (1 << SIZE_BITS)) {
WASM_UNREACHABLE("Type too large");
}
_size = types.size();

auto lookup = [&]() {
auto indexIt = indices.find(types);
if (indexIt != indices.end()) {
Expand All @@ -115,6 +120,9 @@ void Type::init(const std::vector<Type>& types) {
if (lookup()) {
return;
}
if (typeLists.size() >= (1 << ID_BITS)) {
WASM_UNREACHABLE("Too many types!");
}
id = typeLists.size();
typeLists.push_back(std::make_unique<std::vector<Type>>(types));
indices[types] = id;
Expand All @@ -125,7 +133,15 @@ Type::Type(std::initializer_list<Type> types) { init(types); }

Type::Type(const std::vector<Type>& types) { init(types); }

size_t Type::size() const { return expand().size(); }
Type::Type(uint32_t _id) {
id = _id;
{
std::shared_lock<std::shared_timed_mutex> lock(mutex);
_size = typeLists[id]->size();
}
}

size_t Type::size() const { return _size; }

const std::vector<Type>& Type::expand() const {
std::shared_lock<std::shared_timed_mutex> lock(mutex);
Expand All @@ -146,28 +162,34 @@ bool Type::operator<(const Type& other) const {

unsigned Type::getByteSize() const {
// TODO: alignment?
unsigned size = 0;
for (auto t : expand()) {
auto getSingleByteSize = [](Type t) {
switch (t.getSingle()) {
case Type::i32:
case Type::f32:
size += 4;
break;
return 4;
case Type::i64:
case Type::f64:
size += 8;
break;
return 8;
case Type::v128:
size += 16;
break;
return 16;
case Type::funcref:
case Type::anyref:
case Type::nullref:
case Type::exnref:
case Type::none:
case Type::unreachable:
WASM_UNREACHABLE("invalid type");
break;
}
WASM_UNREACHABLE("invalid type");
};

if (isSingle()) {
return getSingleByteSize(*this);
}

unsigned size = 0;
for (auto t : expand()) {
size += getSingleByteSize(t);
}
return size;
}
Expand Down Expand Up @@ -197,25 +219,26 @@ Type Type::reinterpret() const {
}

FeatureSet Type::getFeatures() const {
FeatureSet feats = FeatureSet::MVP;
const auto& elements = expand();
if (elements.size() > 1) {
feats = FeatureSet::Multivalue;
}
for (Type t : elements) {
auto getSingleFeatures = [](Type t) {
switch (t.getSingle()) {
case Type::v128:
feats |= FeatureSet::SIMD;
break;
return FeatureSet::SIMD;
case Type::anyref:
feats |= FeatureSet::ReferenceTypes;
break;
return FeatureSet::ReferenceTypes;
case Type::exnref:
feats |= FeatureSet::ExceptionHandling;
break;
return FeatureSet::ExceptionHandling;
default:
break;
return FeatureSet::MVP;
}
};

if (isSingle()) {
return getSingleFeatures(*this);
}

FeatureSet feats = FeatureSet::Multivalue;
for (Type t : expand()) {
feats |= getSingleFeatures(t);
}
return feats;
}
Expand Down
8 changes: 4 additions & 4 deletions src/wasm/wasm.cpp
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Expand Up @@ -992,11 +992,11 @@ Index Function::getLocalIndex(Name name) {
Index Function::getVarIndexBase() { return sig.params.size(); }

Type Function::getLocalType(Index index) {
const std::vector<Type>& params = sig.params.expand();
if (index < params.size()) {
return params[index];
auto numParams = sig.params.size();
if (index < numParams) {
return sig.params.expand()[index];
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this also seems like a bad path that we should avoid, as each expand takes a lock?

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There's no way to avoid this right now because fetching an element out of a Type requires accessing the underlying vector. Thread-local caches could help, but that would be future work.

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Sounds good.

} else if (isVar(index)) {
return vars[index - params.size()];
return vars[index - numParams];
} else {
WASM_UNREACHABLE("invalid local index");
}
Expand Down