solidity/libyul/AsmAnalysis.cpp

707 lines
21 KiB
C++

/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
// SPDX-License-Identifier: GPL-3.0
/**
* Analyzer part of inline assembly.
*/
#include <libyul/AsmAnalysis.h>
#include <libyul/AST.h>
#include <libyul/AsmAnalysisInfo.h>
#include <libyul/Utilities.h>
#include <libyul/Exceptions.h>
#include <libyul/Object.h>
#include <libyul/Scope.h>
#include <libyul/ScopeFiller.h>
#include <liblangutil/ErrorReporter.h>
#include <libsolutil/CommonData.h>
#include <libsolutil/StringUtils.h>
#include <boost/range/adaptor/reversed.hpp>
#include <boost/algorithm/string.hpp>
#include <memory>
#include <functional>
#include <utility>
using namespace std;
using namespace solidity;
using namespace solidity::yul;
using namespace solidity::util;
using namespace solidity::langutil;
namespace
{
inline string to_string(LiteralKind _kind)
{
switch (_kind)
{
case LiteralKind::Number: return "number";
case LiteralKind::Boolean: return "boolean";
case LiteralKind::String: return "string";
default: yulAssert(false, "");
}
}
}
bool AsmAnalyzer::analyze(Block const& _block)
{
auto watcher = m_errorReporter.errorWatcher();
try
{
if (!(ScopeFiller(m_info, m_errorReporter))(_block))
return false;
(*this)(_block);
}
catch (FatalError const&)
{
// This FatalError con occur if the errorReporter has too many errors.
yulAssert(!watcher.ok(), "Fatal error detected, but no error is reported.");
}
return watcher.ok();
}
AsmAnalysisInfo AsmAnalyzer::analyzeStrictAssertCorrect(Dialect const& _dialect, Object const& _object)
{
ErrorList errorList;
langutil::ErrorReporter errors(errorList);
AsmAnalysisInfo analysisInfo;
bool success = yul::AsmAnalyzer(
analysisInfo,
errors,
_dialect,
{},
_object.qualifiedDataNames()
).analyze(*_object.code);
yulAssert(success && !errors.hasErrors(), "Invalid assembly/yul code.");
return analysisInfo;
}
vector<YulString> AsmAnalyzer::operator()(Literal const& _literal)
{
expectValidType(_literal.type, _literal.location);
if (_literal.kind == LiteralKind::String && _literal.value.str().size() > 32)
m_errorReporter.typeError(
3069_error,
_literal.location,
"String literal too long (" + to_string(_literal.value.str().size()) + " > 32)"
);
else if (_literal.kind == LiteralKind::Number && bigint(_literal.value.str()) > u256(-1))
m_errorReporter.typeError(6708_error, _literal.location, "Number literal too large (> 256 bits)");
else if (_literal.kind == LiteralKind::Boolean)
yulAssert(_literal.value == "true"_yulstring || _literal.value == "false"_yulstring, "");
if (!m_dialect.validTypeForLiteral(_literal.kind, _literal.value, _literal.type))
m_errorReporter.typeError(
5170_error,
_literal.location,
"Invalid type \"" + _literal.type.str() + "\" for literal \"" + _literal.value.str() + "\"."
);
return {_literal.type};
}
vector<YulString> AsmAnalyzer::operator()(Identifier const& _identifier)
{
yulAssert(!_identifier.name.empty(), "");
auto watcher = m_errorReporter.errorWatcher();
YulString type = m_dialect.defaultType;
if (m_currentScope->lookup(_identifier.name, GenericVisitor{
[&](Scope::Variable const& _var)
{
if (!m_activeVariables.count(&_var))
m_errorReporter.declarationError(
4990_error,
_identifier.location,
"Variable " + _identifier.name.str() + " used before it was declared."
);
type = _var.type;
},
[&](Scope::Function const&)
{
m_errorReporter.typeError(
6041_error,
_identifier.location,
"Function " + _identifier.name.str() + " used without being called."
);
}
}))
{
}
else
{
bool found = m_resolver && m_resolver(
_identifier,
yul::IdentifierContext::RValue,
m_currentScope->insideFunction()
);
if (!found && watcher.ok())
// Only add an error message if the callback did not do it.
m_errorReporter.declarationError(
8198_error,
_identifier.location,
"Identifier \"" + _identifier.name.str() + "\" not found."
);
}
return {type};
}
void AsmAnalyzer::operator()(ExpressionStatement const& _statement)
{
auto watcher = m_errorReporter.errorWatcher();
vector<YulString> types = std::visit(*this, _statement.expression);
if (watcher.ok() && !types.empty())
m_errorReporter.typeError(
3083_error,
_statement.location,
"Top-level expressions are not supposed to return values (this expression returns " +
to_string(types.size()) +
" value" +
(types.size() == 1 ? "" : "s") +
"). Use ``pop()`` or assign them."
);
}
void AsmAnalyzer::operator()(Assignment const& _assignment)
{
yulAssert(_assignment.value, "");
size_t const numVariables = _assignment.variableNames.size();
yulAssert(numVariables >= 1, "");
set<YulString> variables;
for (auto const& _variableName: _assignment.variableNames)
if (!variables.insert(_variableName.name).second)
m_errorReporter.declarationError(
9005_error,
_assignment.location,
"Variable " +
_variableName.name.str() +
" occurs multiple times on the left-hand side of the assignment."
);
vector<YulString> types = std::visit(*this, *_assignment.value);
if (types.size() != numVariables)
m_errorReporter.declarationError(
8678_error,
_assignment.location,
"Variable count for assignment to \"" +
joinHumanReadable(applyMap(_assignment.variableNames, [](auto const& _identifier){ return _identifier.name.str(); })) +
"\" does not match number of values (" +
to_string(numVariables) +
" vs. " +
to_string(types.size()) +
")"
);
for (size_t i = 0; i < numVariables; ++i)
if (i < types.size())
checkAssignment(_assignment.variableNames[i], types[i]);
}
void AsmAnalyzer::operator()(VariableDeclaration const& _varDecl)
{
size_t const numVariables = _varDecl.variables.size();
if (m_resolver)
for (auto const& variable: _varDecl.variables)
// Call the resolver for variable declarations to allow it to raise errors on shadowing.
m_resolver(
yul::Identifier{variable.location, variable.name},
yul::IdentifierContext::VariableDeclaration,
m_currentScope->insideFunction()
);
for (auto const& variable: _varDecl.variables)
{
expectValidIdentifier(variable.name, variable.location);
expectValidType(variable.type, variable.location);
}
if (_varDecl.value)
{
vector<YulString> types = std::visit(*this, *_varDecl.value);
if (types.size() != numVariables)
m_errorReporter.declarationError(
3812_error,
_varDecl.location,
"Variable count mismatch for declaration of \"" +
joinHumanReadable(applyMap(_varDecl.variables, [](auto const& _identifier){ return _identifier.name.str(); })) +
+ "\": " +
to_string(numVariables) +
" variables and " +
to_string(types.size()) +
" values."
);
for (size_t i = 0; i < _varDecl.variables.size(); ++i)
{
YulString givenType = m_dialect.defaultType;
if (i < types.size())
givenType = types[i];
TypedName const& variable = _varDecl.variables[i];
if (variable.type != givenType)
m_errorReporter.typeError(
3947_error,
variable.location,
"Assigning value of type \"" + givenType.str() + "\" to variable of type \"" + variable.type.str() + "\"."
);
}
}
for (TypedName const& variable: _varDecl.variables)
m_activeVariables.insert(&std::get<Scope::Variable>(
m_currentScope->identifiers.at(variable.name))
);
}
void AsmAnalyzer::operator()(FunctionDefinition const& _funDef)
{
yulAssert(!_funDef.name.empty(), "");
expectValidIdentifier(_funDef.name, _funDef.location);
Block const* virtualBlock = m_info.virtualBlocks.at(&_funDef).get();
yulAssert(virtualBlock, "");
Scope& varScope = scope(virtualBlock);
for (auto const& var: _funDef.parameters + _funDef.returnVariables)
{
expectValidIdentifier(var.name, var.location);
expectValidType(var.type, var.location);
m_activeVariables.insert(&std::get<Scope::Variable>(varScope.identifiers.at(var.name)));
}
(*this)(_funDef.body);
}
vector<YulString> AsmAnalyzer::operator()(FunctionCall const& _funCall)
{
yulAssert(!_funCall.functionName.name.empty(), "");
auto watcher = m_errorReporter.errorWatcher();
vector<YulString> const* parameterTypes = nullptr;
vector<YulString> const* returnTypes = nullptr;
vector<optional<LiteralKind>> const* literalArguments = nullptr;
if (BuiltinFunction const* f = m_dialect.builtin(_funCall.functionName.name))
{
parameterTypes = &f->parameters;
returnTypes = &f->returns;
if (!f->literalArguments.empty())
literalArguments = &f->literalArguments;
validateInstructions(_funCall);
}
else if (!m_currentScope->lookup(_funCall.functionName.name, GenericVisitor{
[&](Scope::Variable const&)
{
m_errorReporter.typeError(
4202_error,
_funCall.functionName.location,
"Attempt to call variable instead of function."
);
},
[&](Scope::Function const& _fun)
{
parameterTypes = &_fun.arguments;
returnTypes = &_fun.returns;
}
}))
{
if (!validateInstructions(_funCall))
m_errorReporter.declarationError(
4619_error,
_funCall.functionName.location,
"Function \"" + _funCall.functionName.name.str() + "\" not found."
);
yulAssert(!watcher.ok(), "Expected a reported error.");
}
if (parameterTypes && _funCall.arguments.size() != parameterTypes->size())
m_errorReporter.typeError(
7000_error,
_funCall.functionName.location,
"Function \"" + _funCall.functionName.name.str() + "\" expects " +
to_string(parameterTypes->size()) +
" arguments but got " +
to_string(_funCall.arguments.size()) + "."
);
vector<YulString> argTypes;
for (size_t i = _funCall.arguments.size(); i > 0; i--)
{
Expression const& arg = _funCall.arguments[i - 1];
if (
auto literalArgumentKind = (literalArguments && i <= literalArguments->size()) ?
literalArguments->at(i - 1) :
std::nullopt
)
{
if (!holds_alternative<Literal>(arg))
m_errorReporter.typeError(
9114_error,
_funCall.functionName.location,
"Function expects direct literals as arguments."
);
else if (*literalArgumentKind != get<Literal>(arg).kind)
m_errorReporter.typeError(
5859_error,
get<Literal>(arg).location,
"Function expects " + to_string(*literalArgumentKind) + " literal."
);
else if (*literalArgumentKind == LiteralKind::String)
{
if (
_funCall.functionName.name.str() == "datasize" ||
_funCall.functionName.name.str() == "dataoffset"
)
if (!m_dataNames.count(get<Literal>(arg).value))
m_errorReporter.typeError(
3517_error,
get<Literal>(arg).location,
"Unknown data object \"" + std::get<Literal>(arg).value.str() + "\"."
);
argTypes.emplace_back(expectUnlimitedStringLiteral(get<Literal>(arg)));
continue;
}
}
argTypes.emplace_back(expectExpression(arg));
}
std::reverse(argTypes.begin(), argTypes.end());
if (parameterTypes && parameterTypes->size() == argTypes.size())
for (size_t i = 0; i < parameterTypes->size(); ++i)
expectType((*parameterTypes)[i], argTypes[i], locationOf(_funCall.arguments[i]));
if (watcher.ok())
{
yulAssert(parameterTypes && parameterTypes->size() == argTypes.size(), "");
yulAssert(returnTypes, "");
return *returnTypes;
}
else if (returnTypes)
return vector<YulString>(returnTypes->size(), m_dialect.defaultType);
else
return {};
}
void AsmAnalyzer::operator()(If const& _if)
{
expectBoolExpression(*_if.condition);
(*this)(_if.body);
}
void AsmAnalyzer::operator()(Switch const& _switch)
{
yulAssert(_switch.expression, "");
if (_switch.cases.size() == 1 && !_switch.cases[0].value)
m_errorReporter.warning(
9592_error,
_switch.location,
"\"switch\" statement with only a default case."
);
YulString valueType = expectExpression(*_switch.expression);
set<u256> cases;
for (auto const& _case: _switch.cases)
{
if (_case.value)
{
auto watcher = m_errorReporter.errorWatcher();
expectType(valueType, _case.value->type, _case.value->location);
// We cannot use "expectExpression" here because *_case.value is not an
// Expression and would be converted to an Expression otherwise.
(*this)(*_case.value);
/// Note: the parser ensures there is only one default case
if (watcher.ok() && !cases.insert(valueOfLiteral(*_case.value)).second)
m_errorReporter.declarationError(
6792_error,
_case.location,
"Duplicate case \"" +
valueOfLiteral(*_case.value).str() +
"\" defined."
);
}
(*this)(_case.body);
}
}
void AsmAnalyzer::operator()(ForLoop const& _for)
{
yulAssert(_for.condition, "");
Scope* outerScope = m_currentScope;
(*this)(_for.pre);
// The block was closed already, but we re-open it again and stuff the
// condition, the body and the post part inside.
m_currentScope = &scope(&_for.pre);
expectBoolExpression(*_for.condition);
// backup outer for-loop & create new state
auto outerForLoop = m_currentForLoop;
m_currentForLoop = &_for;
(*this)(_for.body);
(*this)(_for.post);
m_currentScope = outerScope;
m_currentForLoop = outerForLoop;
}
void AsmAnalyzer::operator()(Block const& _block)
{
auto previousScope = m_currentScope;
m_currentScope = &scope(&_block);
for (auto const& s: _block.statements)
std::visit(*this, s);
m_currentScope = previousScope;
}
YulString AsmAnalyzer::expectExpression(Expression const& _expr)
{
vector<YulString> types = std::visit(*this, _expr);
if (types.size() != 1)
m_errorReporter.typeError(
3950_error,
locationOf(_expr),
"Expected expression to evaluate to one value, but got " +
to_string(types.size()) +
" values instead."
);
return types.empty() ? m_dialect.defaultType : types.front();
}
YulString AsmAnalyzer::expectUnlimitedStringLiteral(Literal const& _literal)
{
yulAssert(_literal.kind == LiteralKind::String, "");
yulAssert(m_dialect.validTypeForLiteral(LiteralKind::String, _literal.value, _literal.type), "");
return {_literal.type};
}
void AsmAnalyzer::expectBoolExpression(Expression const& _expr)
{
YulString type = expectExpression(_expr);
if (type != m_dialect.boolType)
m_errorReporter.typeError(
1733_error,
locationOf(_expr),
"Expected a value of boolean type \"" +
m_dialect.boolType.str() +
"\" but got \"" +
type.str() +
"\""
);
}
void AsmAnalyzer::checkAssignment(Identifier const& _variable, YulString _valueType)
{
yulAssert(!_variable.name.empty(), "");
auto watcher = m_errorReporter.errorWatcher();
YulString const* variableType = nullptr;
bool found = false;
if (Scope::Identifier const* var = m_currentScope->lookup(_variable.name))
{
if (!holds_alternative<Scope::Variable>(*var))
m_errorReporter.typeError(2657_error, _variable.location, "Assignment requires variable.");
else if (!m_activeVariables.count(&std::get<Scope::Variable>(*var)))
m_errorReporter.declarationError(
1133_error,
_variable.location,
"Variable " + _variable.name.str() + " used before it was declared."
);
else
variableType = &std::get<Scope::Variable>(*var).type;
found = true;
}
else if (m_resolver)
{
bool insideFunction = m_currentScope->insideFunction();
if (m_resolver(_variable, yul::IdentifierContext::LValue, insideFunction))
{
found = true;
variableType = &m_dialect.defaultType;
}
}
if (!found && watcher.ok())
// Only add message if the callback did not.
m_errorReporter.declarationError(4634_error, _variable.location, "Variable not found or variable not lvalue.");
if (variableType && *variableType != _valueType)
m_errorReporter.typeError(
9547_error,
_variable.location,
"Assigning a value of type \"" +
_valueType.str() +
"\" to a variable of type \"" +
variableType->str() +
"\"."
);
yulAssert(!watcher.ok() || variableType, "");
}
Scope& AsmAnalyzer::scope(Block const* _block)
{
yulAssert(m_info.scopes.count(_block) == 1, "Scope requested but not present.");
auto scopePtr = m_info.scopes.at(_block);
yulAssert(scopePtr, "Scope requested but not present.");
return *scopePtr;
}
void AsmAnalyzer::expectValidIdentifier(YulString _identifier, SourceLocation const& _location)
{
// NOTE: the leading dot case is handled by the parser not allowing it.
if (boost::ends_with(_identifier.str(), "."))
m_errorReporter.syntaxError(
3384_error,
_location,
"\"" + _identifier.str() + "\" is not a valid identifier (ends with a dot)."
);
if (_identifier.str().find("..") != std::string::npos)
m_errorReporter.syntaxError(
7771_error,
_location,
"\"" + _identifier.str() + "\" is not a valid identifier (contains consecutive dots)."
);
if (m_dialect.reservedIdentifier(_identifier))
m_errorReporter.declarationError(
5017_error,
_location,
"The identifier \"" + _identifier.str() + "\" is reserved and can not be used."
);
}
void AsmAnalyzer::expectValidType(YulString _type, SourceLocation const& _location)
{
if (!m_dialect.types.count(_type))
m_errorReporter.typeError(
5473_error,
_location,
"\"" + _type.str() + "\" is not a valid type (user defined types are not yet supported)."
);
}
void AsmAnalyzer::expectType(YulString _expectedType, YulString _givenType, SourceLocation const& _location)
{
if (_expectedType != _givenType)
m_errorReporter.typeError(
3781_error,
_location,
"Expected a value of type \"" +
_expectedType.str() +
"\" but got \"" +
_givenType.str() +
"\""
);
}
bool AsmAnalyzer::validateInstructions(std::string const& _instructionIdentifier, langutil::SourceLocation const& _location)
{
auto const builtin = EVMDialect::strictAssemblyForEVM(EVMVersion{}).builtin(YulString(_instructionIdentifier));
if (builtin && builtin->instruction.has_value())
return validateInstructions(builtin->instruction.value(), _location);
else
return false;
}
bool AsmAnalyzer::validateInstructions(evmasm::Instruction _instr, SourceLocation const& _location)
{
// We assume that returndatacopy, returndatasize and staticcall are either all available
// or all not available.
yulAssert(m_evmVersion.supportsReturndata() == m_evmVersion.hasStaticCall(), "");
// Similarly we assume bitwise shifting and create2 go together.
yulAssert(m_evmVersion.hasBitwiseShifting() == m_evmVersion.hasCreate2(), "");
// These instructions are disabled in the dialect.
yulAssert(
_instr != evmasm::Instruction::JUMP &&
_instr != evmasm::Instruction::JUMPI &&
_instr != evmasm::Instruction::JUMPDEST,
"");
auto errorForVM = [&](ErrorId _errorId, string const& vmKindMessage) {
m_errorReporter.typeError(
_errorId,
_location,
"The \"" +
boost::to_lower_copy(instructionInfo(_instr).name)
+ "\" instruction is " +
vmKindMessage +
" VMs " +
"(you are currently compiling for \"" +
m_evmVersion.name() +
"\")."
);
};
if (_instr == evmasm::Instruction::RETURNDATACOPY && !m_evmVersion.supportsReturndata())
errorForVM(7756_error, "only available for Byzantium-compatible");
else if (_instr == evmasm::Instruction::RETURNDATASIZE && !m_evmVersion.supportsReturndata())
errorForVM(4778_error, "only available for Byzantium-compatible");
else if (_instr == evmasm::Instruction::STATICCALL && !m_evmVersion.hasStaticCall())
errorForVM(1503_error, "only available for Byzantium-compatible");
else if (_instr == evmasm::Instruction::SHL && !m_evmVersion.hasBitwiseShifting())
errorForVM(6612_error, "only available for Constantinople-compatible");
else if (_instr == evmasm::Instruction::SHR && !m_evmVersion.hasBitwiseShifting())
errorForVM(7458_error, "only available for Constantinople-compatible");
else if (_instr == evmasm::Instruction::SAR && !m_evmVersion.hasBitwiseShifting())
errorForVM(2054_error, "only available for Constantinople-compatible");
else if (_instr == evmasm::Instruction::CREATE2 && !m_evmVersion.hasCreate2())
errorForVM(6166_error, "only available for Constantinople-compatible");
else if (_instr == evmasm::Instruction::EXTCODEHASH && !m_evmVersion.hasExtCodeHash())
errorForVM(7110_error, "only available for Constantinople-compatible");
else if (_instr == evmasm::Instruction::CHAINID && !m_evmVersion.hasChainID())
errorForVM(1561_error, "only available for Istanbul-compatible");
else if (_instr == evmasm::Instruction::SELFBALANCE && !m_evmVersion.hasSelfBalance())
errorForVM(7721_error, "only available for Istanbul-compatible");
else if (_instr == evmasm::Instruction::PC)
m_errorReporter.error(
2450_error,
Error::Type::SyntaxError,
_location,
"PC instruction is a low-level EVM feature. "
"Because of that PC is disallowed in strict assembly."
);
else
return false;
return true;
}
bool AsmAnalyzer::validateInstructions(FunctionCall const& _functionCall)
{
return validateInstructions(_functionCall.functionName.name.str(), _functionCall.functionName.location);
}