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Track unreachable variables globally instead of per function.

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This commit is contained in:
Daniel Kirchner
2020-10-06 10:38:26 +02:00
parent 756e21a888
commit 0b87849bcb
3 changed files with 19 additions and 37 deletions
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libyul/optimiser/StackToMemoryMover.cpp
+14 -30
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@@ -54,7 +54,7 @@ vector<Statement> generateMemoryStore(
void StackToMemoryMover::run(
OptimiserStepContext& _context,
u256 _reservedMemory,
map<YulString, map<YulString, uint64_t>> const& _memorySlots,
map<YulString, uint64_t> const& _memorySlots,
uint64_t _numRequiredSlots,
Block& _block
)
@@ -66,7 +66,7 @@ void StackToMemoryMover::run(
StackToMemoryMover::StackToMemoryMover(
OptimiserStepContext& _context,
u256 _reservedMemory,
map<YulString, map<YulString, uint64_t>> const& _memorySlots,
map<YulString, uint64_t> const& _memorySlots,
uint64_t _numRequiredSlots
):
m_context(_context),
@@ -80,41 +80,25 @@ m_nameDispenser(_context.dispenser)
evmDialect && evmDialect->providesObjectAccess(),
"StackToMemoryMover can only be run on objects using the EVMDialect with object access."
);
if (m_memorySlots.count(YulString{}))
// If the global scope contains variables to be moved, start with those as if it were a function.
m_currentFunctionMemorySlots = &m_memorySlots.at(YulString{});
}
void StackToMemoryMover::operator()(FunctionDefinition& _functionDefinition)
{
if (m_memorySlots.count(_functionDefinition.name))
{
map<YulString, uint64_t> const* saved = m_currentFunctionMemorySlots;
m_currentFunctionMemorySlots = &m_memorySlots.at(_functionDefinition.name);
for (TypedName const& param: _functionDefinition.parameters + _functionDefinition.returnVariables)
if (m_currentFunctionMemorySlots->count(param.name))
{
// TODO: we cannot handle function parameters yet.
m_currentFunctionMemorySlots = saved;
return;
}
ASTModifier::operator()(_functionDefinition);
m_currentFunctionMemorySlots = saved;
}
for (TypedName const& param: _functionDefinition.parameters + _functionDefinition.returnVariables)
if (m_memorySlots.count(param.name))
{
// TODO: we cannot handle function parameters yet.
return;
}
ASTModifier::operator()(_functionDefinition);
}
void StackToMemoryMover::operator()(Block& _block)
{
using OptionalStatements = std::optional<vector<Statement>>;
if (!m_currentFunctionMemorySlots)
{
ASTModifier::operator()(_block);
return;
}
auto containsVariableNeedingEscalation = [&](auto const& _variables) {
return util::contains_if(_variables, [&](auto const& var) {
return m_currentFunctionMemorySlots->count(var.name);
return m_memorySlots.count(var.name);
});
};
auto rewriteAssignmentOrVariableDeclaration = [&](
@@ -138,7 +122,7 @@ void StackToMemoryMover::operator()(Block& _block)
YulString tempVarName = m_nameDispenser.newName(var.name);
tempDecl.variables.emplace_back(TypedName{var.location, tempVarName, {}});
if (m_currentFunctionMemorySlots->count(var.name))
if (m_memorySlots.count(var.name))
memoryAssignments += generateMemoryStore(
m_context.dialect,
_loc,
@@ -203,7 +187,7 @@ void StackToMemoryMover::visit(Expression& _expression)
{
if (
Identifier* identifier = std::get_if<Identifier>(&_expression);
identifier && m_currentFunctionMemorySlots && m_currentFunctionMemorySlots->count(identifier->name)
identifier && m_memorySlots.count(identifier->name)
)
{
BuiltinFunction const* memoryLoadFunction = m_context.dialect.memoryLoadFunction(m_context.dialect.defaultType);
@@ -227,8 +211,8 @@ void StackToMemoryMover::visit(Expression& _expression)
YulString StackToMemoryMover::memoryOffset(YulString _variable)
{
yulAssert(m_currentFunctionMemorySlots, "");
uint64_t slot = m_currentFunctionMemorySlots->at(_variable);
yulAssert(m_memorySlots.count(_variable), "");
uint64_t slot = m_memorySlots.at(_variable);
yulAssert(slot < m_numRequiredSlots, "");
return YulString{util::toCompactHexWithPrefix(m_reservedMemory + 32 * (m_numRequiredSlots - slot - 1))};
}