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Also optimize memory.

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This commit is contained in:
chriseth
2019-06-20 18:43:37 +02:00
parent 8572600401
commit 2b979cba38
24 changed files with 331 additions and 63 deletions
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libyul/optimiser/DataFlowAnalyzer.cpp
+82 -28
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@@ -40,7 +40,7 @@ using namespace yul;
void DataFlowAnalyzer::operator()(ExpressionStatement& _statement)
{
if (boost::optional<pair<YulString, YulString>> vars = isSimpleSStore(_statement))
if (auto vars = isSimpleStore(dev::eth::Instruction::SSTORE, _statement))
{
ASTModifier::operator()(_statement);
m_storage.set(vars->first, vars->second);
@@ -54,9 +54,22 @@ void DataFlowAnalyzer::operator()(ExpressionStatement& _statement)
for (YulString const& key: keysToErase)
m_storage.eraseKey(key);
}
else if (auto vars = isSimpleStore(dev::eth::Instruction::MSTORE, _statement))
{
ASTModifier::operator()(_statement);
set<YulString> keysToErase;
for (auto const& item: m_memory.values)
if (!m_knowledgeBase.knownToBeDifferentByAtLeast32(vars->first, item.first))
keysToErase.insert(item.first);
// TODO is it fine to do that here?
// can we also move the storage above?
m_memory.set(vars->first, vars->second);
for (YulString const& key: keysToErase)
m_memory.eraseKey(key);
}
else
{
clearStorageKnowledgeIfInvalidated(_statement.expression);
clearKnowledgeIfInvalidated(_statement.expression);
ASTModifier::operator()(_statement);
}
}
@@ -67,7 +80,7 @@ void DataFlowAnalyzer::operator()(Assignment& _assignment)
for (auto const& var: _assignment.variableNames)
names.emplace(var.name);
assertThrow(_assignment.value, OptimizerException, "");
clearStorageKnowledgeIfInvalidated(*_assignment.value);
clearKnowledgeIfInvalidated(*_assignment.value);
visit(*_assignment.value);
handleAssignment(names, _assignment.value.get());
}
@@ -81,7 +94,7 @@ void DataFlowAnalyzer::operator()(VariableDeclaration& _varDecl)
if (_varDecl.value)
{
clearStorageKnowledgeIfInvalidated(*_varDecl.value);
clearKnowledgeIfInvalidated(*_varDecl.value);
visit(*_varDecl.value);
}
@@ -90,12 +103,13 @@ void DataFlowAnalyzer::operator()(VariableDeclaration& _varDecl)
void DataFlowAnalyzer::operator()(If& _if)
{
clearStorageKnowledgeIfInvalidated(*_if.condition);
clearKnowledgeIfInvalidated(*_if.condition);
InvertibleMap<YulString, YulString> storage = m_storage;
InvertibleMap<YulString, YulString> memory = m_memory;
ASTModifier::operator()(_if);
joinStorageKnowledge(storage);
joinKnowledge(storage, memory);
Assignments assignments;
assignments(_if.body);
@@ -104,24 +118,25 @@ void DataFlowAnalyzer::operator()(If& _if)
void DataFlowAnalyzer::operator()(Switch& _switch)
{
clearStorageKnowledgeIfInvalidated(*_switch.expression);
clearKnowledgeIfInvalidated(*_switch.expression);
visit(*_switch.expression);
set<YulString> assignedVariables;
for (auto& _case: _switch.cases)
{
InvertibleMap<YulString, YulString> storage = m_storage;
InvertibleMap<YulString, YulString> memory = m_memory;
(*this)(_case.body);
joinStorageKnowledge(storage);
joinKnowledge(storage, memory);
Assignments assignments;
assignments(_case.body);
assignedVariables += assignments.names();
// This is a little too destructive, we could retain the old values.
clearValues(assignments.names());
clearStorageKnowledgeIfInvalidated(_case.body);
clearKnowledgeIfInvalidated(_case.body);
}
for (auto& _case: _switch.cases)
clearStorageKnowledgeIfInvalidated(_case.body);
clearKnowledgeIfInvalidated(_case.body);
clearValues(assignedVariables);
}
@@ -132,9 +147,11 @@ void DataFlowAnalyzer::operator()(FunctionDefinition& _fun)
map<YulString, Expression const*> value;
InvertibleRelation<YulString> references;
InvertibleMap<YulString, YulString> storage;
InvertibleMap<YulString, YulString> memory;
m_value.swap(value);
swap(m_references, references);
swap(m_storage, storage);
swap(m_memory, memory);
pushScope(true);
for (auto const& parameter: _fun.parameters)
@@ -150,6 +167,7 @@ void DataFlowAnalyzer::operator()(FunctionDefinition& _fun)
m_value.swap(value);
swap(m_references, references);
swap(m_storage, storage);
swap(m_memory, memory);
}
void DataFlowAnalyzer::operator()(ForLoop& _for)
@@ -167,19 +185,19 @@ void DataFlowAnalyzer::operator()(ForLoop& _for)
clearValues(assignments.names());
// break/continue are tricky for storage and thus we almost always clear here.
clearStorageKnowledgeIfInvalidated(*_for.condition);
clearStorageKnowledgeIfInvalidated(_for.post);
clearStorageKnowledgeIfInvalidated(_for.body);
clearKnowledgeIfInvalidated(*_for.condition);
clearKnowledgeIfInvalidated(_for.post);
clearKnowledgeIfInvalidated(_for.body);
visit(*_for.condition);
(*this)(_for.body);
clearValues(assignmentsSinceCont.names());
clearStorageKnowledgeIfInvalidated(_for.body);
clearKnowledgeIfInvalidated(_for.body);
(*this)(_for.post);
clearValues(assignments.names());
clearStorageKnowledgeIfInvalidated(*_for.condition);
clearStorageKnowledgeIfInvalidated(_for.post);
clearStorageKnowledgeIfInvalidated(_for.body);
clearKnowledgeIfInvalidated(*_for.condition);
clearKnowledgeIfInvalidated(_for.post);
clearKnowledgeIfInvalidated(_for.body);
}
void DataFlowAnalyzer::operator()(Block& _block)
@@ -219,6 +237,10 @@ void DataFlowAnalyzer::handleAssignment(set<YulString> const& _variables, Expres
m_storage.eraseKey(name);
// assignment to slot contents denoted by "name"
m_storage.eraseValue(name);
// assignment to slot denoted by "name"
m_memory.eraseKey(name);
// assignment to slot contents denoted by "name"
m_memory.eraseValue(name);
}
}
@@ -257,6 +279,10 @@ void DataFlowAnalyzer::clearValues(set<YulString> _variables)
m_storage.eraseKey(name);
// clear slot contents denoted by "name"
m_storage.eraseValue(name);
// assignment to slot denoted by "name"
m_memory.eraseKey(name);
// assignment to slot contents denoted by "name"
m_memory.eraseValue(name);
}
// Also clear variables that reference variables to be cleared.
@@ -271,29 +297,51 @@ void DataFlowAnalyzer::clearValues(set<YulString> _variables)
m_references.eraseKey(name);
}
void DataFlowAnalyzer::clearStorageKnowledgeIfInvalidated(Block const& _block)
void DataFlowAnalyzer::clearKnowledgeIfInvalidated(Block const& _block)
{
if (SideEffectsCollector(m_dialect, _block).invalidatesStorage())
SideEffectsCollector sideEffects(m_dialect, _block);
if (sideEffects.invalidatesStorage())
m_storage.clear();
if (sideEffects.invalidatesMemory())
m_memory.clear();
}
void DataFlowAnalyzer::clearStorageKnowledgeIfInvalidated(Expression const& _expr)
void DataFlowAnalyzer::clearKnowledgeIfInvalidated(Expression const& _expr)
{
if (SideEffectsCollector(m_dialect, _expr).invalidatesStorage())
SideEffectsCollector sideEffects(m_dialect, _expr);
if (sideEffects.invalidatesStorage())
m_storage.clear();
if (sideEffects.invalidatesMemory())
m_memory.clear();
}
void DataFlowAnalyzer::joinStorageKnowledge(InvertibleMap<YulString, YulString> const& _other)
void DataFlowAnalyzer::joinKnowledge(
InvertibleMap<YulString, YulString> const& _olderStorage,
InvertibleMap<YulString, YulString> const& _olderMemory
)
{
joinKnowledgeHelper(m_storage, _olderStorage);
joinKnowledgeHelper(m_memory, _olderMemory);
}
void DataFlowAnalyzer::joinKnowledgeHelper(
InvertibleMap<YulString, YulString>& _this,
InvertibleMap<YulString, YulString> const& _older
)
{
// We clear if the key does not exist in the older map or if the value is different.
// This also works for memory because _older is an "older version"
// of m_memory and thus any overlapping write would have cleared the keys
// that are not known to be different inside m_memory already.
set<YulString> keysToErase;
for (auto const& item: m_storage.values)
for (auto const& item: _this.values)
{
auto it = _other.values.find(item.first);
if (it == _other.values.end() || it->second != item.second)
auto it = _older.values.find(item.first);
if (it == _older.values.end() || it->second != item.second)
keysToErase.insert(item.first);
}
for (auto const& key: keysToErase)
m_storage.eraseKey(key);
_this.eraseKey(key);
}
bool DataFlowAnalyzer::inScope(YulString _variableName) const
@@ -308,16 +356,22 @@ bool DataFlowAnalyzer::inScope(YulString _variableName) const
return false;
}
boost::optional<pair<YulString, YulString>> DataFlowAnalyzer::isSimpleSStore(
boost::optional<pair<YulString, YulString>> DataFlowAnalyzer::isSimpleStore(
dev::eth::Instruction _store,
ExpressionStatement const& _statement
) const
{
yulAssert(
_store == dev::eth::Instruction::MSTORE ||
_store == dev::eth::Instruction::SSTORE,
""
);
if (_statement.expression.type() == typeid(FunctionCall))
{
FunctionCall const& funCall = boost::get<FunctionCall>(_statement.expression);
if (EVMDialect const* dialect = dynamic_cast<EVMDialect const*>(&m_dialect))
if (auto const* builtin = dialect->builtin(funCall.functionName.name))
if (builtin->instruction == dev::eth::Instruction::SSTORE)
if (builtin->instruction == _store)
if (
funCall.arguments.at(0).type() == typeid(Identifier) &&
funCall.arguments.at(1).type() == typeid(Identifier)