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Refactor variable access.

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This commit is contained in:
chriseth 2017-02-16 10:12:54 +01:00
parent f4f82615b1
commit caa3761dc9
1 changed files with 30 additions and 40 deletions
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70
libsolidity/inlineasm/AsmCodeGen.cpp
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@ -140,28 +140,11 @@ public:
if (m_scope.lookup(_identifier.name, Scope::NonconstVisitor( if (m_scope.lookup(_identifier.name, Scope::NonconstVisitor(
[=](Scope::Variable& _var) [=](Scope::Variable& _var)
{ {
if (!_var.active) if (int heightDiff = variableHeightDiff(_var, _identifier.location, false))
{
m_state.addError(
Error::Type::TypeError,
"Variable used before it was declared",
_identifier.location
);
m_state.assembly.append(u256(0));
return;
}
int heightDiff = m_state.assembly.deposit() - _var.stackHeight;
if (heightDiff <= 0 || heightDiff > 16)
{
m_state.addError(
Error::Type::TypeError,
"Variable inaccessible, too deep inside stack (" + boost::lexical_cast<string>(heightDiff) + ")",
_identifier.location
);
m_state.assembly.append(u256(0));
}
else
m_state.assembly.append(solidity::dupInstruction(heightDiff)); m_state.assembly.append(solidity::dupInstruction(heightDiff));
else
// Store something to balance the stack
m_state.assembly.append(u256(0));
}, },
[=](Scope::Label& _label) [=](Scope::Label& _label)
{ {
@ -266,25 +249,8 @@ private:
if (m_scope.lookup(_variableName.name, Scope::Visitor( if (m_scope.lookup(_variableName.name, Scope::Visitor(
[=](Scope::Variable const& _var) [=](Scope::Variable const& _var)
{ {
if (!_var.active) if (int heightDiff = variableHeightDiff(_var, _location, true))
{ m_state.assembly.append(solidity::swapInstruction(heightDiff - 1));
m_state.addError(
Error::Type::TypeError,
"Variable used before it was declared",
_location
);
m_state.assembly.append(u256(0));
return;
}
int heightDiff = m_state.assembly.deposit() - _var.stackHeight - 1;
if (heightDiff <= 0 || heightDiff > 16)
m_state.addError(
Error::Type::TypeError,
"Variable inaccessible, too deep inside stack (" + boost::lexical_cast<string>(heightDiff) + ")",
_location
);
else
m_state.assembly.append(solidity::swapInstruction(heightDiff));
m_state.assembly.append(solidity::Instruction::POP); m_state.assembly.append(solidity::Instruction::POP);
}, },
[=](Scope::Label const&) [=](Scope::Label const&)
@ -304,6 +270,30 @@ private:
); );
} }
/// Determines the stack height difference to the given variables. Automatically generates
/// errors if it is not yet in scope or the height difference is too large. Returns 0 on
/// errors and the (positive) stack height difference otherwise.
int variableHeightDiff(Scope::Variable const& _var, SourceLocation const& _location, bool _forSwap)
{
if (!_var.active)
{
m_state.addError( Error::Type::TypeError, "Variable used before it was declared", _location);
return 0;
}
int heightDiff = m_state.assembly.deposit() - _var.stackHeight;
if (heightDiff <= (_forSwap ? 1 : 0) || heightDiff > (_forSwap ? 17 : 16))
{
m_state.addError(
Error::Type::TypeError,
"Variable inaccessible, too deep inside stack (" + boost::lexical_cast<string>(heightDiff) + ")",
_location
);
return 0;
}
else
return heightDiff;
}
void expectDeposit(int _deposit, int _oldHeight, SourceLocation const& _location) void expectDeposit(int _deposit, int _oldHeight, SourceLocation const& _location)
{ {
if (m_state.assembly.deposit() != _oldHeight + 1) if (m_state.assembly.deposit() != _oldHeight + 1)