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Fix argument stack slot reuse for functions without return variables.

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This commit is contained in:
Daniel Kirchner 2021-04-15 15:13:31 +02:00
parent f1a474e599
commit 8a4497a8d3
3 changed files with 37 additions and 2 deletions
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6
libyul/backends/evm/EVMCodeTransform.cpp
View File

@ -402,7 +402,7 @@ void CodeTransform::operator()(FunctionDefinition const& _function)
subTransform.deleteVariable(var);
}
if (!m_allowStackOpt || _function.returnVariables.empty())
if (!m_allowStackOpt)
subTransform.setupReturnVariablesAndFunctionExit();
subTransform(_function.body);
@ -592,6 +592,7 @@ void CodeTransform::visitExpression(Expression const& _expression)
void CodeTransform::setupReturnVariablesAndFunctionExit()
{
yulAssert(isInsideFunction(), "");
yulAssert(!returnVariablesAndFunctionExitAreSetup(), "");
yulAssert(m_scope, "");
@ -654,7 +655,8 @@ void CodeTransform::visitStatements(vector<Statement> const& _statements)
{
freeUnusedVariables();
if (
!m_delayedReturnVariables.empty() &&
isInsideFunction() &&
!returnVariablesAndFunctionExitAreSetup() &&
statementNeedsReturnVariableSetup(statement, m_delayedReturnVariables)
)
setupReturnVariablesAndFunctionExit();

4
libyul/backends/evm/EVMCodeTransform.h
View File

@ -183,6 +183,10 @@ private:
{
return m_functionExitStackHeight.has_value();
}
bool isInsideFunction() const
{
return m_functionExitLabel.has_value();
}
AbstractAssembly& m_assembly;
AsmAnalysisInfo& m_info;

29
test/libyul/evmCodeTransform/stackReuse/function_argument_reuse_without_retparams.yul Normal file
View File

@ -0,0 +1,29 @@
{
function f(x, y) {
mstore(0x80, x)
if calldataload(0) { sstore(y, y) }
}
}
// ====
// stackOptimization: true
// ----
// PUSH1 0x17
// JUMP
// JUMPDEST
// DUP1
// PUSH1 0x80
// MSTORE
// POP
// PUSH1 0x0
// CALLDATALOAD
// ISZERO
// PUSH1 0x13
// JUMPI
// DUP1
// DUP2
// SSTORE
// JUMPDEST
// POP
// JUMPDEST
// JUMP
// JUMPDEST