Merge pull request #5240 from ethereum/limitDispenserSize

[Yul] Limit name length created by dispenser
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chriseth 2018-10-17 22:54:38 +02:00 committed by GitHub
commit 7609e2871e
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8 changed files with 97 additions and 25 deletions

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@ -47,9 +47,8 @@ public:
solidity::assembly::AsmAnalysisInfo const& _analysisInfo,
std::set<std::string> 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:

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@ -41,11 +41,10 @@ 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();
// Determine constants
SSAValueTracker tracker;
@ -157,7 +156,7 @@ vector<Statement> 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)
@ -170,7 +169,7 @@ vector<Statement> 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<Block>(newBody).statements);
boost::apply_visitor(GenericFallbackVisitor<Assignment, VariableDeclaration>{
@ -203,15 +202,10 @@ vector<Statement> 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);
}

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@ -116,8 +116,6 @@ private:
boost::optional<std::vector<Statement>> tryInlineStatement(Statement& _statement);
std::vector<Statement> performInline(Statement& _statement, FunctionCall& _funCall);
std::string newName(std::string const& _prefix);
std::string m_currentFunction;
FullInliner& m_driver;
NameDispenser& m_nameDispenser;

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@ -20,18 +20,43 @@
#include <libyul/optimiser/NameDispenser.h>
#include <libyul/optimiser/NameCollector.h>
#include <libsolidity/inlineasm/AsmData.h>
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<string> _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;

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@ -19,6 +19,8 @@
*/
#pragma once
#include <libyul/ASTDataForward.h>
#include <set>
#include <string>
@ -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<std::string> _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<std::string> m_usedNames;
};

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@ -106,8 +106,7 @@ bool YulOptimizerTest::run(ostream& _stream, string const& _linePrefix, bool con
}
else if (m_optimizerStep == "expressionSplitter")
{
NameDispenser nameDispenser;
nameDispenser.m_usedNames = NameCollector(*m_ast).names();
NameDispenser nameDispenser(*m_ast);
ExpressionSplitter{nameDispenser}(*m_ast);
}
else if (m_optimizerStep == "functionGrouper")
@ -130,8 +129,7 @@ bool YulOptimizerTest::run(ostream& _stream, string const& _linePrefix, bool con
disambiguate();
(FunctionHoister{})(*m_ast);
(FunctionGrouper{})(*m_ast);
NameDispenser nameDispenser;
nameDispenser.m_usedNames = NameCollector(*m_ast).names();
NameDispenser nameDispenser(*m_ast);
ExpressionSplitter{nameDispenser}(*m_ast);
FullInliner(*m_ast).run();
ExpressionJoiner::run(*m_ast);
@ -155,8 +153,7 @@ bool YulOptimizerTest::run(ostream& _stream, string const& _linePrefix, bool con
else if (m_optimizerStep == "fullSimplify")
{
disambiguate();
NameDispenser nameDispenser;
nameDispenser.m_usedNames = NameCollector(*m_ast).names();
NameDispenser nameDispenser(*m_ast);
ExpressionSplitter{nameDispenser}(*m_ast);
CommonSubexpressionEliminator{}(*m_ast);
ExpressionSimplifier::run(*m_ast);

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@ -0,0 +1,12 @@
// yul
{ { let aanteuhdaoneudbrgkjiuaothduiathudaoeuh:u256 } { let aanteuhdaoneudbrgkjiuaothduiathudaoeuh:u256 } }
// ----
// disambiguator
// {
// {
// let aanteuhdaoneudbrgkjiuaothduiathudaoeuh:u256
// }
// {
// let aanteuhdaoneudbrgkjiuaothduiathudaoeuh_1:u256
// }
// }

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@ -0,0 +1,25 @@
{
function verylongfunctionname(verylongvariablename) -> verylongvariablename2 {
verylongvariablename2 := add(verylongvariablename, verylongvariablename)
}
// same long name
let verylongvariablename2 := 3
mstore(0, verylongfunctionname(verylongvariablename2))
mstore(1, verylongvariablename2)
}
// ----
// fullInliner
// {
// {
// let verylongvariablename2_1 := 3
// let verylongfu_verylongvariablename := verylongvariablename2_1
// let verylongfu_verylongvariablename2
// verylongfu_verylongvariablename2 := add(verylongfu_verylongvariablename, verylongfu_verylongvariablename)
// mstore(0, verylongfu_verylongvariablename2)
// mstore(1, verylongvariablename2_1)
// }
// function verylongfunctionname(verylongvariablename) -> verylongvariablename2
// {
// verylongvariablename2 := add(verylongvariablename, verylongvariablename)
// }
// }