From 732d09cef1548e2111c47b6f5b04a54db10a9d41 Mon Sep 17 00:00:00 2001 From: chriseth Date: Tue, 16 Oct 2018 17:01:13 +0200 Subject: Limit size of generated names and add convenience constructors. --- libyul/optimiser/Disambiguator.h | 3 +-- libyul/optimiser/FullInliner.cpp | 14 ++++---------- libyul/optimiser/FullInliner.h | 2 -- libyul/optimiser/NameDispenser.cpp | 31 ++++++++++++++++++++++++++++--- libyul/optimiser/NameDispenser.h | 26 ++++++++++++++++++++++++-- 5 files changed, 57 insertions(+), 19 deletions(-) (limited to 'libyul') diff --git a/libyul/optimiser/Disambiguator.h b/libyul/optimiser/Disambiguator.h index e16ebfbf..74a491ab 100644 --- a/libyul/optimiser/Disambiguator.h +++ b/libyul/optimiser/Disambiguator.h @@ -47,9 +47,8 @@ public: solidity::assembly::AsmAnalysisInfo const& _analysisInfo, std::set const& _externallyUsedIdentifiers = {} ): - m_info(_analysisInfo), m_externallyUsedIdentifiers(_externallyUsedIdentifiers) + m_info(_analysisInfo), m_externallyUsedIdentifiers(_externallyUsedIdentifiers), m_nameDispenser(m_externallyUsedIdentifiers) { - m_nameDispenser.m_usedNames = m_externallyUsedIdentifiers; } protected: diff --git a/libyul/optimiser/FullInliner.cpp b/libyul/optimiser/FullInliner.cpp index cd0ed52a..c20c2b08 100644 --- a/libyul/optimiser/FullInliner.cpp +++ b/libyul/optimiser/FullInliner.cpp @@ -39,11 +39,10 @@ using namespace dev::yul; using namespace dev::solidity; FullInliner::FullInliner(Block& _ast): - m_ast(_ast) + m_ast(_ast), m_nameDispenser(_ast) { assertThrow(m_ast.statements.size() >= 1, OptimizerException, ""); assertThrow(m_ast.statements.front().type() == typeid(Block), OptimizerException, ""); - m_nameDispenser.m_usedNames = NameCollector(m_ast).names(); for (size_t i = 1; i < m_ast.statements.size(); ++i) { @@ -112,7 +111,7 @@ vector InlineModifier::performInline(Statement& _statement, FunctionC // helper function to create a new variable that is supposed to model // an existing variable. auto newVariable = [&](TypedName const& _existingVariable, Expression* _value) { - string newName = m_nameDispenser.newName(function.name + "_" + _existingVariable.name); + string newName = m_nameDispenser.newName(_existingVariable.name, function.name); variableReplacements[_existingVariable.name] = newName; VariableDeclaration varDecl{_funCall.location, {{_funCall.location, newName, _existingVariable.type}}, {}}; if (_value) @@ -125,7 +124,7 @@ vector InlineModifier::performInline(Statement& _statement, FunctionC for (auto const& var: function.returnVariables) newVariable(var, nullptr); - Statement newBody = BodyCopier(m_nameDispenser, function.name + "_", variableReplacements)(function.body); + Statement newBody = BodyCopier(m_nameDispenser, function.name, variableReplacements)(function.body); newStatements += std::move(boost::get(newBody).statements); boost::apply_visitor(GenericFallbackVisitor{ @@ -158,15 +157,10 @@ vector InlineModifier::performInline(Statement& _statement, FunctionC return newStatements; } -string InlineModifier::newName(string const& _prefix) -{ - return m_nameDispenser.newName(_prefix); -} - Statement BodyCopier::operator()(VariableDeclaration const& _varDecl) { for (auto const& var: _varDecl.variables) - m_variableReplacements[var.name] = m_nameDispenser.newName(m_varNamePrefix + var.name); + m_variableReplacements[var.name] = m_nameDispenser.newName(var.name, m_varNamePrefix); return ASTCopier::operator()(_varDecl); } diff --git a/libyul/optimiser/FullInliner.h b/libyul/optimiser/FullInliner.h index 495286c0..5037b56e 100644 --- a/libyul/optimiser/FullInliner.h +++ b/libyul/optimiser/FullInliner.h @@ -106,8 +106,6 @@ private: boost::optional> tryInlineStatement(Statement& _statement); std::vector performInline(Statement& _statement, FunctionCall& _funCall); - std::string newName(std::string const& _prefix); - std::string m_currentFunction; FullInliner& m_driver; NameDispenser& m_nameDispenser; diff --git a/libyul/optimiser/NameDispenser.cpp b/libyul/optimiser/NameDispenser.cpp index f7385471..d3f10bc2 100644 --- a/libyul/optimiser/NameDispenser.cpp +++ b/libyul/optimiser/NameDispenser.cpp @@ -20,18 +20,43 @@ #include +#include + +#include + using namespace std; using namespace dev; using namespace dev::yul; -string NameDispenser::newName(string const& _prefix) +NameDispenser::NameDispenser(Block const& _ast): + NameDispenser(NameCollector(_ast).names()) +{ +} + +NameDispenser::NameDispenser(set _usedNames): + m_usedNames(std::move(_usedNames)) +{ +} + +string NameDispenser::newName(string const& _nameHint, string const& _context) +{ + // Shortening rules: Use a suffix of _prefix and a prefix of _context. + string prefix = _nameHint; + + if (!_context.empty()) + prefix = _context.substr(0, 10) + "_" + prefix; + + return newNameInternal(prefix); +} + +string NameDispenser::newNameInternal(string const& _nameHint) { - string name = _prefix; size_t suffix = 0; + string name = _nameHint; while (name.empty() || m_usedNames.count(name)) { suffix++; - name = _prefix + "_" + to_string(suffix); + name = _nameHint + "_" + to_string(suffix); } m_usedNames.insert(name); return name; diff --git a/libyul/optimiser/NameDispenser.h b/libyul/optimiser/NameDispenser.h index 64ec318f..5fbf5f8e 100644 --- a/libyul/optimiser/NameDispenser.h +++ b/libyul/optimiser/NameDispenser.h @@ -19,6 +19,8 @@ */ #pragma once +#include + #include #include @@ -27,9 +29,29 @@ namespace dev namespace yul { -struct NameDispenser +/** + * Optimizer component that can be used to generate new names that + * do not conflict with existing names. + * + * Tries to keep names short and appends decimals to disambiguate. + */ +class NameDispenser { - std::string newName(std::string const& _prefix); +public: + /// Initialize the name dispenser with all the names used in the given AST. + explicit NameDispenser(Block const& _ast); + /// Initialize the name dispenser with the given used names. + explicit NameDispenser(std::set _usedNames); + + /// @returns a currently unused name that should be similar to _nameHint + /// and prefixed by _context if present. + /// If the resulting name would be too long, trims the context at the end + /// and the name hint at the start. + std::string newName(std::string const& _nameHint, std::string const& _context = {}); + +private: + std::string newNameInternal(std::string const& _nameHint); + std::set m_usedNames; }; -- cgit