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Remove stack height checks.

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This commit is contained in:
chriseth
2020-01-28 15:26:17 +01:00
committed by Mathias Baumann
parent 0dd398e2ac
commit f0afb0aeff
5 changed files with 7 additions and 91 deletions
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libyul/backends/evm/EVMCodeTransform.cpp
+4 -48
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@@ -102,7 +102,6 @@ CodeTransform::CodeTransform(
bool _evm15,
ExternalIdentifierAccess const& _identifierAccess,
bool _useNamedLabelsForFunctions,
int _stackAdjustment,
shared_ptr<Context> _context
):
m_assembly(_assembly),
@@ -113,7 +112,6 @@ CodeTransform::CodeTransform(
m_evm15(_evm15),
m_useNamedLabelsForFunctions(_useNamedLabelsForFunctions),
m_identifierAccess(_identifierAccess),
m_stackAdjustment(_stackAdjustment),
m_context(_context)
{
if (!m_context)
@@ -159,7 +157,6 @@ void CodeTransform::freeUnusedVariables()
{
yulAssert(m_unusedStackSlots.erase(m_assembly.stackHeight() - 1), "");
m_assembly.appendInstruction(evmasm::Instruction::POP);
--m_stackAdjustment;
}
}
@@ -178,11 +175,11 @@ void CodeTransform::operator()(VariableDeclaration const& _varDecl)
yulAssert(m_scope, "");
int const numVariables = _varDecl.variables.size();
int height = m_assembly.stackHeight();
int heightAtStart = m_assembly.stackHeight();
if (_varDecl.value)
{
std::visit(*this, *_varDecl.value);
expectDeposit(numVariables, height);
expectDeposit(numVariables, heightAtStart);
}
else
{
@@ -196,7 +193,7 @@ void CodeTransform::operator()(VariableDeclaration const& _varDecl)
{
YulString varName = _varDecl.variables[varIndex].name;
auto& var = std::get<Scope::Variable>(m_scope->identifiers.at(varName));
m_context->variableStackHeights[&var] = height + varIndex;
m_context->variableStackHeights[&var] = heightAtStart + varIndex;
if (!m_allowStackOpt)
continue;
@@ -207,7 +204,6 @@ void CodeTransform::operator()(VariableDeclaration const& _varDecl)
m_context->variableStackHeights.erase(&var);
m_assembly.setSourceLocation(_varDecl.location);
m_assembly.appendInstruction(evmasm::Instruction::POP);
--m_stackAdjustment;
}
else
m_variablesScheduledForDeletion.insert(&var);
@@ -223,10 +219,8 @@ void CodeTransform::operator()(VariableDeclaration const& _varDecl)
if (int heightDiff = variableHeightDiff(var, varName, true))
m_assembly.appendInstruction(evmasm::swapInstruction(heightDiff - 1));
m_assembly.appendInstruction(evmasm::Instruction::POP);
--m_stackAdjustment;
}
}
checkStackHeight(&_varDecl);
}
void CodeTransform::stackError(StackTooDeepError _error, int _targetStackHeight)
@@ -249,14 +243,12 @@ void CodeTransform::operator()(Assignment const& _assignment)
m_assembly.setSourceLocation(_assignment.location);
generateMultiAssignment(_assignment.variableNames);
checkStackHeight(&_assignment);
}
void CodeTransform::operator()(ExpressionStatement const& _statement)
{
m_assembly.setSourceLocation(_statement.location);
std::visit(*this, _statement.expression);
checkStackHeight(&_statement);
}
void CodeTransform::operator()(FunctionCall const& _call)
@@ -279,7 +271,6 @@ void CodeTransform::operator()(FunctionCall const& _call)
{
returnLabel = m_assembly.newLabelId();
m_assembly.appendLabelReference(returnLabel);
m_stackAdjustment++;
}
Scope::Function* function = nullptr;
@@ -298,9 +289,7 @@ void CodeTransform::operator()(FunctionCall const& _call)
{
m_assembly.appendJumpTo(functionEntryID(_call.functionName.name, *function), function->returns.size() - function->arguments.size() - 1);
m_assembly.appendLabel(returnLabel);
m_stackAdjustment--;
}
checkStackHeight(&_call);
}
}
@@ -334,15 +323,12 @@ void CodeTransform::operator()(Identifier const& _identifier)
"Identifier not found and no external access available."
);
m_identifierAccess.generateCode(_identifier, IdentifierContext::RValue, m_assembly);
checkStackHeight(&_identifier);
}
void CodeTransform::operator()(Literal const& _literal)
{
m_assembly.setSourceLocation(_literal.location);
m_assembly.appendConstant(valueOfLiteral(_literal));
checkStackHeight(&_literal);
}
void CodeTransform::operator()(If const& _if)
@@ -355,7 +341,6 @@ void CodeTransform::operator()(If const& _if)
(*this)(_if.body);
m_assembly.setSourceLocation(_if.location);
m_assembly.appendLabel(end);
checkStackHeight(&_if);
}
void CodeTransform::operator()(Switch const& _switch)
@@ -403,7 +388,6 @@ void CodeTransform::operator()(Switch const& _switch)
m_assembly.setSourceLocation(_switch.location);
m_assembly.appendLabel(end);
m_assembly.appendInstruction(evmasm::Instruction::POP);
checkStackHeight(&_switch);
}
void CodeTransform::operator()(FunctionDefinition const& _function)
@@ -412,8 +396,7 @@ void CodeTransform::operator()(FunctionDefinition const& _function)
yulAssert(m_scope->identifiers.count(_function.name), "");
Scope::Function& function = std::get<Scope::Function>(m_scope->identifiers.at(_function.name));
int const localStackAdjustment = m_evm15 ? 0 : 1;
int height = localStackAdjustment;
int height = m_evm15 ? 0 : 1;
yulAssert(m_info.scopes.at(&_function.body), "");
Scope* varScope = m_info.scopes.at(m_info.virtualBlocks.at(&_function).get()).get();
yulAssert(varScope, "");
@@ -433,8 +416,6 @@ void CodeTransform::operator()(FunctionDefinition const& _function)
m_assembly.setStackHeight(height);
m_stackAdjustment += localStackAdjustment;
for (auto const& v: _function.returnVariables)
{
auto& var = std::get<Scope::Variable>(varScope->identifiers.at(v.name));
@@ -458,7 +439,6 @@ void CodeTransform::operator()(FunctionDefinition const& _function)
m_evm15,
m_identifierAccess,
m_useNamedLabelsForFunctions,
localStackAdjustment,
m_context
)(_function.body);
}
@@ -527,8 +507,6 @@ void CodeTransform::operator()(FunctionDefinition const& _function)
m_assembly.appendReturnsub(_function.returnVariables.size(), stackHeightBefore);
else
m_assembly.appendJump(stackHeightBefore - _function.returnVariables.size());
m_stackAdjustment -= localStackAdjustment;
checkStackHeight(&_function);
m_assembly.setStackHeight(stackHeightBefore);
}
@@ -569,7 +547,6 @@ void CodeTransform::operator()(ForLoop const& _forLoop)
finalizeBlock(_forLoop.pre, stackStartHeight);
m_context->forLoopStack.pop();
m_scope = originalScope;
checkStackHeight(&_forLoop);
}
int CodeTransform::appendPopUntil(int _targetDepth)
@@ -587,8 +564,6 @@ void CodeTransform::operator()(Break const& _break)
Context::JumpInfo const& jump = m_context->forLoopStack.top().done;
m_assembly.appendJumpTo(jump.label, appendPopUntil(jump.targetStackHeight));
checkStackHeight(&_break);
}
void CodeTransform::operator()(Continue const& _continue)
@@ -598,8 +573,6 @@ void CodeTransform::operator()(Continue const& _continue)
Context::JumpInfo const& jump = m_context->forLoopStack.top().post;
m_assembly.appendJumpTo(jump.label, appendPopUntil(jump.targetStackHeight));
checkStackHeight(&_continue);
}
void CodeTransform::operator()(Leave const& _leaveStatement)
@@ -609,8 +582,6 @@ void CodeTransform::operator()(Leave const& _leaveStatement)
Context::JumpInfo const& jump = m_context->functionExitPoints.top();
m_assembly.appendJumpTo(jump.label, appendPopUntil(jump.targetStackHeight));
checkStackHeight(&_leaveStatement);
}
void CodeTransform::operator()(Block const& _block)
@@ -693,7 +664,6 @@ void CodeTransform::finalizeBlock(Block const& _block, int blockStartStackHeight
{
yulAssert(!m_context->variableStackHeights.count(&var), "");
yulAssert(!m_context->variableReferences.count(&var), "");
m_stackAdjustment++;
}
else
m_assembly.appendInstruction(evmasm::Instruction::POP);
@@ -701,7 +671,6 @@ void CodeTransform::finalizeBlock(Block const& _block, int blockStartStackHeight
int deposit = m_assembly.stackHeight() - blockStartStackHeight;
yulAssert(deposit == 0, "Invalid stack height at end of block: " + to_string(deposit));
checkStackHeight(&_block);
}
void CodeTransform::generateMultiAssignment(vector<Identifier> const& _variableNames)
@@ -758,16 +727,3 @@ void CodeTransform::expectDeposit(int _deposit, int _oldHeight) const
yulAssert(m_assembly.stackHeight() == _oldHeight + _deposit, "Invalid stack deposit.");
}
void CodeTransform::checkStackHeight(void const* _astElement) const
{
yulAssert(m_info.stackHeightInfo.count(_astElement), "Stack height for AST element not found.");
int stackHeightInAnalysis = m_info.stackHeightInfo.at(_astElement);
int stackHeightInCodegen = m_assembly.stackHeight() - m_stackAdjustment;
yulAssert(
stackHeightInAnalysis == stackHeightInCodegen,
"Stack height mismatch between analysis and code generation phase: Analysis: " +
to_string(stackHeightInAnalysis) +
" code gen: " +
to_string(stackHeightInCodegen)
);
}