AsmAnalysis.cpp

/*
	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 <libsolutil/Visitor.h>

#include <libevmasm/Instruction.h>

#include <boost/algorithm/string.hpp>

#include <fmt/format.h>

#include <functional>

using namespace std::string_literals;
using namespace solidity;
using namespace solidity::yul;
using namespace solidity::util;
using namespace solidity::langutil;

namespace
{
inline std::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
	{
		// FIXME: Pass location of the object name. Now it's a location of first code section in yul
		validateObjectStructure(nativeLocationOf(_block));
		if (!(ScopeFiller(m_info, m_errorReporter))(_block))
			return false;

		(*this)(_block);
	}
	catch (FatalError const&)
	{
		// NOTE: There's a cap on the number of reported errors, but watcher.ok() will work fine even if
		// we exceed it because the reporter keeps counting (it just stops adding errors to the list).
		// Note also that fact of exceeding the cap triggers a FatalError so one can get thrown even
		// if we don't make any of our errors fatal.
		if (watcher.ok())
		{
			std::cerr << "Unreported fatal error:" << std::endl;
			std::cerr << boost::current_exception_diagnostic_information() << std::endl;
			yulAssert(false, "Unreported fatal error.");
		}
	}
	return watcher.ok();
}

AsmAnalysisInfo AsmAnalyzer::analyzeStrictAssertCorrect(Object const& _object)
{
	yulAssert(_object.dialect());
	return analyzeStrictAssertCorrect(*_object.dialect(), *_object.code(), _object.summarizeStructure());
}

AsmAnalysisInfo AsmAnalyzer::analyzeStrictAssertCorrect(
	Dialect const& _dialect,
	AST const& _ast,
	Object::Structure _objectStructure
)
{
	return analyzeStrictAssertCorrect(_dialect, _ast.root(), std::move(_objectStructure));
}

AsmAnalysisInfo AsmAnalyzer::analyzeStrictAssertCorrect(
	Dialect const& _dialect,
	Block const& _astRoot,
	Object::Structure _objectStructure
)
{
	ErrorList errorList;
	langutil::ErrorReporter errors(errorList);
	AsmAnalysisInfo analysisInfo;
	bool success = AsmAnalyzer(
		analysisInfo,
		errors,
		_dialect,
		{},
		std::move(_objectStructure)
	).analyze(_astRoot);

	if (!success)
	{
		auto formatErrors = [](ErrorList const& _errorList) {
			std::vector<std::string> formattedErrors;
			for (std::shared_ptr<Error const> const& error: _errorList)
			{
				yulAssert(error->comment());
				formattedErrors.push_back(fmt::format(
					// Intentionally not showing source locations because we don't have the original
					// source here and it's unlikely they match the pretty-printed version.
					// They may not even match the original source if the AST was modified by the optimizer.
					"- {} {}: {}",
					Error::formatErrorType(error->type()),
					error->errorId().error,
					*error->comment()
				));
			}
			return joinHumanReadable(formattedErrors, "\n");
		};

		yulAssert(errors.hasErrors(), "Yul analysis failed but did not report any errors.");
		yulAssert(false, fmt::format(
			"{}\n\nExpected valid Yul, but errors were reported during analysis:\n{}",
			AsmPrinter{_dialect}(_astRoot),
			formatErrors(errorList)
		));
	}

	yulAssert(!errors.hasErrors());
	return analysisInfo;
}

size_t AsmAnalyzer::operator()(Literal const& _literal)
{
	bool erroneousLiteralValue = false;
	if (_literal.kind == LiteralKind::String && !_literal.value.unlimited() && _literal.value.hint() && _literal.value.hint()->size() > 32)
	{
		erroneousLiteralValue = true;
		m_errorReporter.typeError(
			3069_error,
			nativeLocationOf(_literal),
			fmt::format("String literal too long ({} > 32)", formatLiteral(_literal, false /* _validated */ ).size())
		);
	}
	else if (_literal.kind == LiteralKind::Number && _literal.value.hint() && bigint(*_literal.value.hint()) > u256(-1))
	{
		erroneousLiteralValue = true;
		m_errorReporter.typeError(6708_error, nativeLocationOf(_literal), "Number literal too large (> 256 bits)");
	}

	yulAssert(erroneousLiteralValue ^ validLiteral(_literal), "Invalid literal after validating it through AsmAnalyzer.");
	return 1;
}

size_t AsmAnalyzer::operator()(Identifier const& _identifier)
{
	yulAssert(!_identifier.name.empty());
	auto watcher = m_errorReporter.errorWatcher();

	if (m_currentScope->lookup(_identifier.name, GenericVisitor{
		[&](Scope::Variable const& _var)
		{
			if (!m_activeVariables.count(&_var))
				m_errorReporter.declarationError(
					4990_error,
					nativeLocationOf(_identifier),
					fmt::format("Variable {} used before it was declared.", _identifier.name.str())
				);
		},
		[&](Scope::Function const&)
		{
			m_errorReporter.typeError(
				6041_error,
				nativeLocationOf(_identifier),
				fmt::format("Function {} used without being called.", _identifier.name.str())
			);
		}
	}))
	{
		if (m_resolver)
			// We found a local reference, make sure there is no external reference.
			// Used for side effects, e.g., error reporting in TypeChecker, hence ignoring return value
			std::ignore = m_resolver(
				_identifier,
				yul::IdentifierContext::NonExternal,
				m_currentScope->insideFunction()
			);
	}
	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,
				nativeLocationOf(_identifier),
				fmt::format("Identifier \"{}\" not found.", _identifier.name.str())
			);

	}

	return 1;
}

void AsmAnalyzer::operator()(ExpressionStatement const& _statement)
{
	auto watcher = m_errorReporter.errorWatcher();
	size_t numReturns = std::visit(*this, _statement.expression);
	if (watcher.ok() && numReturns > 0)
		m_errorReporter.typeError(
			3083_error,
			nativeLocationOf(_statement),
			fmt::format(
				"Top-level expressions are not supposed to return values (this expression returns {} value{}). "
				"Use ``pop()`` or assign them.",
				numReturns,
				numReturns == 1 ? "" : "s"
			)
		);
}

void AsmAnalyzer::operator()(Assignment const& _assignment)
{
	yulAssert(_assignment.value, "");
	size_t const numVariables = _assignment.variableNames.size();
	yulAssert(numVariables >= 1, "");

	std::set<YulName> variables;
	for (auto const& _variableName: _assignment.variableNames)
		if (!variables.insert(_variableName.name).second)
			m_errorReporter.declarationError(
				9005_error,
				nativeLocationOf(_assignment),
				fmt::format(
					"Variable {} occurs multiple times on the left-hand side of the assignment.",
					_variableName.name.str()
				)
			);

	size_t numRhsValues = std::visit(*this, *_assignment.value);

	if (numRhsValues != numVariables)
		m_errorReporter.declarationError(
			8678_error,
			nativeLocationOf(_assignment),
			fmt::format(
				"Variable count for assignment to \"{}\" does not match number of values ({} vs. {})",
				joinHumanReadable(applyMap(_assignment.variableNames, [](auto const& _identifier){ return _identifier.name.str(); })),
				numVariables,
				numRhsValues
			)
		);

	for (size_t i = 0; i < numVariables; ++i)
		checkAssignment(_assignment.variableNames[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.debugData, variable.name},
				yul::IdentifierContext::VariableDeclaration,
				m_currentScope->insideFunction()
			);
	for (auto const& variable: _varDecl.variables)
	{
		expectValidIdentifier(variable.name, nativeLocationOf(variable));
	}

	if (_varDecl.value)
	{
		size_t numValues = std::visit(*this, *_varDecl.value);
		if (numValues != numVariables)
			m_errorReporter.declarationError(
				3812_error,
				nativeLocationOf(_varDecl),
				fmt::format(
					"Variable count mismatch for declaration of \"{}\": {} variables and {} values.",
					joinHumanReadable(applyMap(_varDecl.variables, [](auto const& _identifier){ return _identifier.name.str(); })),
					numVariables,
					numValues
				)
			);
	}

	for (NameWithDebugData 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, nativeLocationOf(_funDef));
	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, nativeLocationOf(var));
		m_activeVariables.insert(&std::get<Scope::Variable>(varScope.identifiers.at(var.name)));
	}

	if (m_eofVersion.has_value())
	{
		if (_funDef.parameters.size() >= 0x80)
			m_errorReporter.typeError(
				8534_error,
				nativeLocationOf(_funDef),
				"Too many function parameters. At most 127 parameters allowed for EOF"
			);

		if (_funDef.returnVariables.size() >= 0x80)
			m_errorReporter.typeError(
				2101_error,
				nativeLocationOf(_funDef),
				"Too many function return variables. At most 127 return variables allowed for EOF"
			);
	}

	(*this)(_funDef.body);
}

size_t AsmAnalyzer::operator()(FunctionCall const& _funCall)
{
	auto watcher = m_errorReporter.errorWatcher();
	std::optional<size_t> numParameters;
	std::optional<size_t> numReturns;
	std::vector<std::optional<LiteralKind>> const* literalArguments = nullptr;

	std::visit(
		GenericVisitor {
			[&](BuiltinName const& _builtinName)
			{
				BuiltinFunction const& builtin = m_dialect.builtin(_builtinName.handle);
				if (builtin.name == "selfdestruct")
					m_errorReporter.warning(
						1699_error,
						nativeLocationOf(_builtinName),
						"\"selfdestruct\" has been deprecated. "
						"Note that, starting from the Cancun hard fork, the underlying opcode no longer deletes the code and "
						"data associated with an account and only transfers its Ether to the beneficiary, "
						"unless executed in the same transaction in which the contract was created (see EIP-6780). "
						"Any use in newly deployed contracts is strongly discouraged even if the new behavior is taken into account. "
						"Future changes to the EVM might further reduce the functionality of the opcode."
					);
				else if (
					builtin.name == "tstore" &&
					!m_errorReporter.hasError({2394})
				)
				{
					yulAssert(m_evmVersion.supportsTransientStorage(), "tstore is only a builtin on EVMs that support transient storage");
					m_errorReporter.warning(
						2394_error,
						nativeLocationOf(_builtinName),
						"Transient storage as defined by EIP-1153 can break the composability of smart contracts: "
						"Since transient storage is cleared only at the end of the transaction and not at the end of the outermost call frame to the contract within a transaction, "
						"your contract may unintentionally misbehave when invoked multiple times in a complex transaction. "
						"To avoid this, be sure to clear all transient storage at the end of any call to your contract. "
						"The use of transient storage for reentrancy guards that are cleared at the end of the call is safe."
					);
				}

				numParameters = builtin.numParameters;
				numReturns = builtin.numReturns;
				if (!builtin.literalArguments.empty())
					literalArguments = &builtin.literalArguments;

				validateInstructions(_funCall);
				m_sideEffects += builtin.sideEffects;
			},
			[&](Identifier const& _identifier)
			{
				bool const identifierInCurrentScope = m_currentScope->lookup(_identifier.name, GenericVisitor{
					[&](Scope::Variable const&)
					{
						m_errorReporter.typeError(
							4202_error,
							nativeLocationOf(_identifier),
							"Attempt to call variable instead of function."
						);
					},
					[&](Scope::Function const& _fun)
					{
						numParameters = _fun.numArguments;
						numReturns = _fun.numReturns;
					}
				});
				if (identifierInCurrentScope)
				{
					if (m_resolver)
						// We found a local reference, make sure there is no external reference.
						// Used for side effects, e.g., error reporting in TypeChecker, hence ignoring return value
						std::ignore = m_resolver(
							_identifier,
							yul::IdentifierContext::NonExternal,
							m_currentScope->insideFunction()
						);
				}
				else
				{
					if (!validateInstructions(_funCall))
						m_errorReporter.declarationError(
							4619_error,
							nativeLocationOf(_identifier),
							fmt::format("Function \"{}\" not found.", _identifier.name.str())
						);
					yulAssert(!watcher.ok(), "Expected a reported error.");
				}
			}
		},
		_funCall.functionName
	);

	if (numParameters && _funCall.arguments.size() != *numParameters)
		m_errorReporter.typeError(
			7000_error,
			nativeLocationOf(_funCall.functionName),
			fmt::format(
				"Function \"{}\" expects {} arguments but got {}.",
				resolveFunctionName(_funCall.functionName, m_dialect),
				*numParameters,
				_funCall.arguments.size()
			)
		);

	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 (!std::holds_alternative<Literal>(arg))
				m_errorReporter.typeError(
					9114_error,
					nativeLocationOf(_funCall.functionName),
					"Function expects direct literals as arguments."
				);
			else if (*literalArgumentKind != std::get<Literal>(arg).kind)
				m_errorReporter.typeError(
					5859_error,
					nativeLocationOf(arg),
					fmt::format("Function expects {} literal.", to_string(*literalArgumentKind))
				);
			else if (*literalArgumentKind == LiteralKind::String)
			{
				std::string_view functionName = resolveFunctionName(_funCall.functionName, m_dialect);
				if (functionName == "datasize" || functionName == "dataoffset")
				{
					auto const& argumentAsLiteral = std::get<Literal>(arg);
					if (!m_objectStructure.contains(formatLiteral(argumentAsLiteral)))
						m_errorReporter.typeError(
							3517_error,
							nativeLocationOf(arg),
							fmt::format("Unknown data object \"{}\".", formatLiteral(argumentAsLiteral))
						);
				}
				else if (functionName.substr(0, "verbatim_"s.size()) == "verbatim_")
				{
					auto const& literalValue = std::get<Literal>(arg).value;
					yulAssert(literalValue.unlimited());  // verbatim literals are always unlimited
					if (literalValue.builtinStringLiteralValue().empty())
						m_errorReporter.typeError(
							1844_error,
							nativeLocationOf(arg),
							"The \"verbatim_*\" builtins cannot be used with empty bytecode."
						);
				}
				else if (functionName == "eofcreate" || functionName == "returncontract")
				{
					auto const& argumentAsLiteral = std::get<Literal>(arg);
					auto const formattedLiteral = formatLiteral(argumentAsLiteral);

					if (util::contains(formattedLiteral, '.'))
						m_errorReporter.typeError(
							2186_error,
							nativeLocationOf(arg),
							fmt::format("Name required but path given as \"{}\" argument.", functionName)
						);

					if (!m_objectStructure.topLevelSubObjectNames().count(formattedLiteral))
					{
						if (m_objectStructure.containsData(formattedLiteral))
							m_errorReporter.typeError(
								7575_error,
								nativeLocationOf(arg),
								fmt::format(
									"Data name \"{}\" cannot be used as an argument of eofcreate/returncontract. "
									"Only an object name is acceptable.",
									formattedLiteral
								)
							);
						else
							m_errorReporter.typeError(
								8970_error,
								nativeLocationOf(arg),
								fmt::format("Unknown object \"{}\".", formattedLiteral)
							);
					}
				}
				expectUnlimitedStringLiteral(std::get<Literal>(arg));
				continue;
			}
			else if (*literalArgumentKind == LiteralKind::Number)
			{
				std::string_view functionName = resolveFunctionName(_funCall.functionName, m_dialect);
				if (functionName == "auxdataloadn")
				{
					auto const& argumentAsLiteral = std::get<Literal>(arg);
					if (argumentAsLiteral.value.value() > std::numeric_limits<uint16_t>::max())
						m_errorReporter.typeError(
							5202_error,
							nativeLocationOf(arg),
							"Invalid auxdataloadn argument value. Offset must be in range 0...0xFFFF"
						);
				}
			}
		}
		expectExpression(arg);
	}

	if (watcher.ok())
	{
		yulAssert(numParameters && numParameters == _funCall.arguments.size());
		yulAssert(numReturns);
		return *numReturns;
	}
	else if (numReturns)
		return *numReturns;
	else
		return {};
}

void AsmAnalyzer::operator()(If const& _if)
{
	expectExpression(*_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,
			nativeLocationOf(_switch),
			"\"switch\" statement with only a default case."
		);

	expectExpression(*_switch.expression);

	std::set<u256> cases;
	for (auto const& _case: _switch.cases)
	{
		if (_case.value)
		{
			auto watcher = m_errorReporter.errorWatcher();

			// 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(_case.value->value.value()).second)
				m_errorReporter.declarationError(
					6792_error,
					nativeLocationOf(_case),
					fmt::format("Duplicate case \"{}\" defined.", formatLiteral(*_case.value))
				);
		}

		(*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);

	expectExpression(*_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;
}

void AsmAnalyzer::expectExpression(Expression const& _expr)
{
	size_t numValues = std::visit(*this, _expr);
	if (numValues != 1)
		m_errorReporter.typeError(
			3950_error,
			nativeLocationOf(_expr),
			fmt::format(
				"Expected expression to evaluate to one value, but got {} values instead.",
				numValues
			)
		);
}

void AsmAnalyzer::expectUnlimitedStringLiteral(Literal const& _literal)
{
	yulAssert(_literal.kind == LiteralKind::String);
	yulAssert(_literal.value.unlimited());
}

void AsmAnalyzer::checkAssignment(Identifier const& _variable)
{
	yulAssert(!_variable.name.empty());
	auto watcher = m_errorReporter.errorWatcher();
	bool hasVariable = false;
	bool found = false;
	if (Scope::Identifier const* var = m_currentScope->lookup(_variable.name))
	{
		if (m_resolver)
			// We found a local reference, make sure there is no external reference.
			// Used for side effects, e.g., error reporting in TypeChecker, hence ignoring return value
			std::ignore = m_resolver(
				_variable,
				yul::IdentifierContext::NonExternal,
				m_currentScope->insideFunction()
			);

		if (!std::holds_alternative<Scope::Variable>(*var))
			m_errorReporter.typeError(2657_error, nativeLocationOf(_variable), "Assignment requires variable.");
		else if (!m_activeVariables.count(&std::get<Scope::Variable>(*var)))
			m_errorReporter.declarationError(
				1133_error,
				nativeLocationOf(_variable),
				fmt::format("Variable {} used before it was declared.", _variable.name.str())
			);
		else
			hasVariable = true;
		found = true;
	}
	else if (m_resolver)
	{
		bool insideFunction = m_currentScope->insideFunction();
		if (m_resolver(_variable, yul::IdentifierContext::LValue, insideFunction))
		{
			found = true;
			hasVariable = true;
		}
	}

	if (!found && watcher.ok())
		// Only add message if the callback did not.
		m_errorReporter.declarationError(4634_error, nativeLocationOf(_variable), "Variable not found or variable not lvalue.");

	yulAssert(!watcher.ok() || hasVariable, "");
}

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(YulName _identifier, SourceLocation const& _location)
{
	std::string_view const label = _identifier.str();
	// NOTE: the leading dot case is handled by the parser not allowing it.
	if (label.ends_with('.'))
		m_errorReporter.syntaxError(
			3384_error,
			_location,
			fmt::format("\"{}\" is not a valid identifier (ends with a dot).", label)
		);

	if (label.find("..") != std::string::npos)
		m_errorReporter.syntaxError(
			7771_error,
			_location,
			fmt::format("\"{}\" is not a valid identifier (contains consecutive dots).", label)
		);

	if (m_dialect.reservedIdentifier(label))
		m_errorReporter.declarationError(
			5017_error,
			_location,
			fmt::format("The identifier \"{}\" is reserved and can not be used.", label)
		);
}

bool AsmAnalyzer::validateInstructions(std::string_view _instructionIdentifier, langutil::SourceLocation const& _location)
{
	// NOTE: This function uses the default EVM version instead of the currently selected one.
	auto const& defaultEVMDialect = EVMDialect::strictAssemblyForEVMObjects(EVMVersion{}, std::nullopt);
	auto const builtinHandle = defaultEVMDialect.findBuiltin(_instructionIdentifier);
	if (builtinHandle && defaultEVMDialect.builtin(*builtinHandle).instruction.has_value())
		return validateInstructions(*defaultEVMDialect.builtin(*builtinHandle).instruction, _location);

	solAssert(!m_eofVersion.has_value() || *m_eofVersion == 1);
	auto const& eofDialect = EVMDialect::strictAssemblyForEVMObjects(EVMVersion::firstWithEOF(), 1);
	auto const eofBuiltinHandle = eofDialect.findBuiltin(_instructionIdentifier);
	if (eofBuiltinHandle)
	{
		auto const builtin = eofDialect.builtin(*eofBuiltinHandle);
		if (builtin.instruction.has_value())
			return validateInstructions(*builtin.instruction, _location);
		// If builtin is available in EOF but not available in legacy (and we build to legacy) generate custom error.
		else if (!m_eofVersion.has_value() && !builtinHandle)
		{
			m_errorReporter.declarationError(
				7223_error,
				_location,
				fmt::format(
					"Builtin function \"{function}\" is only available in EOF.",
					fmt::arg("function", _instructionIdentifier)
				)
			);
			return true;
		}
	}

	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 &&
		_instr != evmasm::Instruction::DATALOADN &&
		_instr != evmasm::Instruction::EOFCREATE &&
		_instr != evmasm::Instruction::RETURNCONTRACT &&
		_instr != evmasm::Instruction::RJUMP &&
		_instr != evmasm::Instruction::RJUMPI &&
		_instr != evmasm::Instruction::CALLF &&
		_instr != evmasm::Instruction::JUMPF &&
		_instr != evmasm::Instruction::RETF &&
		_instr != evmasm::Instruction::DUPN &&
		_instr != evmasm::Instruction::SWAPN
	);

	auto errorForVM = [&](ErrorId _errorId, std::string const& vmKindMessage) {
		m_errorReporter.typeError(
			_errorId,
			_location,
			fmt::format(
				"The \"{instruction}\" instruction is {kind} VMs (you are currently compiling for \"{version}\").",
				fmt::arg("instruction", boost::to_lower_copy(instructionInfo(_instr, m_evmVersion).name)),
				fmt::arg("kind", vmKindMessage),
				fmt::arg("version", m_evmVersion.name())
			)
		);
	};

	// The errors below are meant to be issued when processing an undeclared identifier matching a builtin name
	// present on the default EVM version but not on the currently selected one,
	// since the other `validateInstructions()` overload uses the default EVM version.
	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::BASEFEE && !m_evmVersion.hasBaseFee())
		errorForVM(5430_error, "only available for London-compatible");
	else if (_instr == evmasm::Instruction::BLOBBASEFEE && !m_evmVersion.hasBlobBaseFee())
		errorForVM(6679_error, "only available for Cancun-compatible");
	else if (_instr == evmasm::Instruction::BLOBHASH && !m_evmVersion.hasBlobHash())
		errorForVM(8314_error, "only available for Cancun-compatible");
	else if (_instr == evmasm::Instruction::MCOPY && !m_evmVersion.hasMcopy())
		errorForVM(7755_error, "only available for Cancun-compatible");
	else if ((_instr == evmasm::Instruction::TSTORE || _instr == evmasm::Instruction::TLOAD) && !m_evmVersion.supportsTransientStorage())
		errorForVM(6243_error, "only available for Cancun-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 if (!m_eofVersion.has_value() && (
		_instr == evmasm::Instruction::EXTCALL ||
		_instr == evmasm::Instruction::EXTDELEGATECALL ||
		_instr == evmasm::Instruction::EXTSTATICCALL
	))
	{
		m_errorReporter.typeError(
			4328_error,
			_location,
			fmt::format(
				"The \"{instruction}\" instruction is only available in EOF.",
				fmt::arg("instruction", boost::to_lower_copy(instructionInfo(_instr, m_evmVersion).name))
			)
		);
	}
	else if (m_eofVersion.has_value() && (
		_instr == evmasm::Instruction::CALL ||
		_instr == evmasm::Instruction::CALLCODE ||
		_instr == evmasm::Instruction::DELEGATECALL ||
		_instr == evmasm::Instruction::STATICCALL ||
		_instr == evmasm::Instruction::SELFDESTRUCT ||
		_instr == evmasm::Instruction::JUMP ||
		_instr == evmasm::Instruction::JUMPI ||
		_instr == evmasm::Instruction::PC ||
		_instr == evmasm::Instruction::CREATE ||
		_instr == evmasm::Instruction::CREATE2 ||
		_instr == evmasm::Instruction::CODESIZE ||
		_instr == evmasm::Instruction::CODECOPY ||
		_instr == evmasm::Instruction::EXTCODESIZE ||
		_instr == evmasm::Instruction::EXTCODECOPY ||
		_instr == evmasm::Instruction::EXTCODEHASH ||
		_instr == evmasm::Instruction::GAS
	))
	{
		m_errorReporter.typeError(
			9132_error,
			_location,
			fmt::format(
				"The \"{instruction}\" instruction is {kind} VMs (you are currently compiling to EOF).",
				fmt::arg("instruction", boost::to_lower_copy(instructionInfo(_instr, m_evmVersion).name)),
				fmt::arg("kind", "only available in legacy bytecode")
			)
		);
	}
	else
	{
		// Sanity check
		solAssert(m_evmVersion.hasOpcode(_instr, m_eofVersion));
		return false;
	}

	// Sanity check
	// PC is not available in strict assembly but it is always valid opcode in legacy evm.
	solAssert(_instr == evmasm::Instruction::PC || !m_evmVersion.hasOpcode(_instr, m_eofVersion));
	return true;
}

bool AsmAnalyzer::validateInstructions(FunctionCall const& _functionCall)
{
	return validateInstructions(
		resolveFunctionName(_functionCall.functionName, m_dialect),
		nativeLocationOf(_functionCall.functionName)
	);
}

void AsmAnalyzer::validateObjectStructure(langutil::SourceLocation const& _astRootLocation)
{
	if (m_eofVersion.has_value())
	{
		if (util::contains(m_objectStructure.objectName, '.')) // No dots in object name for EOF
			m_errorReporter.syntaxError(
				9822_error,
				_astRootLocation,
				fmt::format(
					"The object name \"{objectName}\" is invalid in EOF context. Object names must not contain 'dot' character.",
					fmt::arg("objectName", m_objectStructure.objectName)
				)
			);
		else if (m_objectStructure.topLevelSubObjectNames().size() > 256)
		{
			m_errorReporter.syntaxError(
				1305_error,
				_astRootLocation,
				fmt::format(
					"Too many subobjects in \"{objectName}\". At most 256 subobjects allowed when compiling to EOF",
					fmt::arg("objectName", m_objectStructure.objectName)
				)
			);
		}
	}
}