Optimise simplification rules (sort into bins).

1 files changed, 11 insertions, 327 deletions

diff --git a/libevmasm/ExpressionClasses.cpp b/libevmasm/ExpressionClasses.cpp
index fccac1b0..fc283b0b 100644
--- a/libevmasm/ExpressionClasses.cpp
+++ b/libevmasm/ExpressionClasses.cpp
@@ -29,6 +29,7 @@
 #include <boost/noncopyable.hpp>
 #include <libevmasm/Assembly.h>
 #include <libevmasm/CommonSubexpressionEliminator.h>
+#include <libevmasm/SimplificationRules.h>
 
 using namespace std;
 using namespace dev;
@@ -180,191 +181,6 @@ string ExpressionClasses::fullDAGToString(ExpressionClasses::Id _id) const
 	return str.str();
 }
 
-class Rules: public boost::noncopyable
-{
-public:
-	Rules();
-	void resetMatchGroups() { m_matchGroups.clear(); }
-	vector<pair<Pattern, function<Pattern()>>> const& rules() const { return m_rules; }
-
-private:
-	using Expression = ExpressionClasses::Expression;
-	map<unsigned, Expression const*> m_matchGroups;
-	vector<pair<Pattern, function<Pattern()>>> m_rules;
-};
-
-template <class S> S divWorkaround(S const& _a, S const& _b)
-{
-	return (S)(bigint(_a) / bigint(_b));
-}
-
-template <class S> S modWorkaround(S const& _a, S const& _b)
-{
-	return (S)(bigint(_a) % bigint(_b));
-}
-
-Rules::Rules()
-{
-	// Multiple occurences of one of these inside one rule must match the same equivalence class.
-	// Constants.
-	Pattern A(Push);
-	Pattern B(Push);
-	Pattern C(Push);
-	// Anything.
-	Pattern X;
-	Pattern Y;
-	Pattern Z;
-	A.setMatchGroup(1, m_matchGroups);
-	B.setMatchGroup(2, m_matchGroups);
-	C.setMatchGroup(3, m_matchGroups);
-	X.setMatchGroup(4, m_matchGroups);
-	Y.setMatchGroup(5, m_matchGroups);
-	Z.setMatchGroup(6, m_matchGroups);
-
-	m_rules = vector<pair<Pattern, function<Pattern()>>>{
-		// arithmetics on constants
-		{{Instruction::ADD, {A, B}}, [=]{ return A.d() + B.d(); }},
-		{{Instruction::MUL, {A, B}}, [=]{ return A.d() * B.d(); }},
-		{{Instruction::SUB, {A, B}}, [=]{ return A.d() - B.d(); }},
-		{{Instruction::DIV, {A, B}}, [=]{ return B.d() == 0 ? 0 : divWorkaround(A.d(), B.d()); }},
-		{{Instruction::SDIV, {A, B}}, [=]{ return B.d() == 0 ? 0 : s2u(divWorkaround(u2s(A.d()), u2s(B.d()))); }},
-		{{Instruction::MOD, {A, B}}, [=]{ return B.d() == 0 ? 0 : modWorkaround(A.d(), B.d()); }},
-		{{Instruction::SMOD, {A, B}}, [=]{ return B.d() == 0 ? 0 : s2u(modWorkaround(u2s(A.d()), u2s(B.d()))); }},
-		{{Instruction::EXP, {A, B}}, [=]{ return u256(boost::multiprecision::powm(bigint(A.d()), bigint(B.d()), bigint(1) << 256)); }},
-		{{Instruction::NOT, {A}}, [=]{ return ~A.d(); }},
-		{{Instruction::LT, {A, B}}, [=]() { return A.d() < B.d() ? u256(1) : 0; }},
-		{{Instruction::GT, {A, B}}, [=]() -> u256 { return A.d() > B.d() ? 1 : 0; }},
-		{{Instruction::SLT, {A, B}}, [=]() -> u256 { return u2s(A.d()) < u2s(B.d()) ? 1 : 0; }},
-		{{Instruction::SGT, {A, B}}, [=]() -> u256 { return u2s(A.d()) > u2s(B.d()) ? 1 : 0; }},
-		{{Instruction::EQ, {A, B}}, [=]() -> u256 { return A.d() == B.d() ? 1 : 0; }},
-		{{Instruction::ISZERO, {A}}, [=]() -> u256 { return A.d() == 0 ? 1 : 0; }},
-		{{Instruction::AND, {A, B}}, [=]{ return A.d() & B.d(); }},
-		{{Instruction::OR, {A, B}}, [=]{ return A.d() | B.d(); }},
-		{{Instruction::XOR, {A, B}}, [=]{ return A.d() ^ B.d(); }},
-		{{Instruction::BYTE, {A, B}}, [=]{ return A.d() >= 32 ? 0 : (B.d() >> unsigned(8 * (31 - A.d()))) & 0xff; }},
-		{{Instruction::ADDMOD, {A, B, C}}, [=]{ return C.d() == 0 ? 0 : u256((bigint(A.d()) + bigint(B.d())) % C.d()); }},
-		{{Instruction::MULMOD, {A, B, C}}, [=]{ return C.d() == 0 ? 0 : u256((bigint(A.d()) * bigint(B.d())) % C.d()); }},
-		{{Instruction::MULMOD, {A, B, C}}, [=]{ return A.d() * B.d(); }},
-		{{Instruction::SIGNEXTEND, {A, B}}, [=]() -> u256 {
-			if (A.d() >= 31)
-				return B.d();
-			unsigned testBit = unsigned(A.d()) * 8 + 7;
-			u256 mask = (u256(1) << testBit) - 1;
-			return u256(boost::multiprecision::bit_test(B.d(), testBit) ? B.d() | ~mask : B.d() & mask);
-		}},
-
-		// invariants involving known constants
-		{{Instruction::ADD, {X, 0}}, [=]{ return X; }},
-		{{Instruction::SUB, {X, 0}}, [=]{ return X; }},
-		{{Instruction::MUL, {X, 1}}, [=]{ return X; }},
-		{{Instruction::DIV, {X, 1}}, [=]{ return X; }},
-		{{Instruction::SDIV, {X, 1}}, [=]{ return X; }},
-		{{Instruction::OR, {X, 0}}, [=]{ return X; }},
-		{{Instruction::XOR, {X, 0}}, [=]{ return X; }},
-		{{Instruction::AND, {X, ~u256(0)}}, [=]{ return X; }},
-		{{Instruction::AND, {X, 0}}, [=]{ return u256(0); }},
-		{{Instruction::MUL, {X, 0}}, [=]{ return u256(0); }},
-		{{Instruction::DIV, {X, 0}}, [=]{ return u256(0); }},
-		{{Instruction::DIV, {0, X}}, [=]{ return u256(0); }},
-		{{Instruction::MOD, {X, 0}}, [=]{ return u256(0); }},
-		{{Instruction::MOD, {0, X}}, [=]{ return u256(0); }},
-		{{Instruction::OR, {X, ~u256(0)}}, [=]{ return ~u256(0); }},
-		{{Instruction::EQ, {X, 0}}, [=]() -> Pattern { return {Instruction::ISZERO, {X}}; } },
-		// operations involving an expression and itself
-		{{Instruction::AND, {X, X}}, [=]{ return X; }},
-		{{Instruction::OR, {X, X}}, [=]{ return X; }},
-		{{Instruction::XOR, {X, X}}, [=]{ return u256(0); }},
-		{{Instruction::SUB, {X, X}}, [=]{ return u256(0); }},
-		{{Instruction::EQ, {X, X}}, [=]{ return u256(1); }},
-		{{Instruction::LT, {X, X}}, [=]{ return u256(0); }},
-		{{Instruction::SLT, {X, X}}, [=]{ return u256(0); }},
-		{{Instruction::GT, {X, X}}, [=]{ return u256(0); }},
-		{{Instruction::SGT, {X, X}}, [=]{ return u256(0); }},
-		{{Instruction::MOD, {X, X}}, [=]{ return u256(0); }},
-
-		{{Instruction::NOT, {{Instruction::NOT, {X}}}}, [=]{ return X; }},
-		{{Instruction::XOR, {{{X}, {Instruction::XOR, {X, Y}}}}}, [=]{ return Y; }},
-		{{Instruction::OR, {{{X}, {Instruction::AND, {X, Y}}}}}, [=]{ return X; }},
-		{{Instruction::AND, {{{X}, {Instruction::OR, {X, Y}}}}}, [=]{ return X; }},
-		{{Instruction::AND, {{{X}, {Instruction::NOT, {X}}}}}, [=]{ return u256(0); }},
-		{{Instruction::OR, {{{X}, {Instruction::NOT, {X}}}}}, [=]{ return ~u256(0); }},
-	};
-	// Double negation of opcodes with binary result
-	for (auto const& op: vector<Instruction>{
-		Instruction::EQ,
-		Instruction::LT,
-		Instruction::SLT,
-		Instruction::GT,
-		Instruction::SGT
-	})
-		m_rules.push_back({
-			{Instruction::ISZERO, {{Instruction::ISZERO, {{op, {X, Y}}}}}},
-			[=]() -> Pattern { return {op, {X, Y}}; }
-		});
-	m_rules.push_back({
-		{Instruction::ISZERO, {{Instruction::ISZERO, {{Instruction::ISZERO, {X}}}}}},
-		[=]() -> Pattern { return {Instruction::ISZERO, {X}}; }
-	});
-	m_rules.push_back({
-		{Instruction::ISZERO, {{Instruction::XOR, {X, Y}}}},
-		[=]() -> Pattern { return { Instruction::EQ, {X, Y} }; }
-	});
-	// Associative operations
-	for (auto const& opFun: vector<pair<Instruction,function<u256(u256 const&,u256 const&)>>>{
-		{Instruction::ADD, plus<u256>()},
-		{Instruction::MUL, multiplies<u256>()},
-		{Instruction::AND, bit_and<u256>()},
-		{Instruction::OR, bit_or<u256>()},
-		{Instruction::XOR, bit_xor<u256>()}
-	})
-	{
-		auto op = opFun.first;
-		auto fun = opFun.second;
-		// Moving constants to the outside, order matters here!
-		// we need actions that return expressions (or patterns?) here, and we need also reversed rules
-		// (X+A)+B -> X+(A+B)
-		m_rules += vector<pair<Pattern, function<Pattern()>>>{{
-			{op, {{op, {X, A}}, B}},
-			[=]() -> Pattern { return {op, {X, fun(A.d(), B.d())}}; }
-		}, {
-		// X+(Y+A) -> (X+Y)+A
-			{op, {{op, {X, A}}, Y}},
-			[=]() -> Pattern { return {op, {{op, {X, Y}}, A}}; }
-		}, {
-		// For now, we still need explicit commutativity for the inner pattern
-			{op, {{op, {A, X}}, B}},
-			[=]() -> Pattern { return {op, {X, fun(A.d(), B.d())}}; }
-		}, {
-			{op, {{op, {A, X}}, Y}},
-			[=]() -> Pattern { return {op, {{op, {X, Y}}, A}}; }
-		}};
-	}
-	// move constants across subtractions
-	m_rules += vector<pair<Pattern, function<Pattern()>>>{
-		{
-			// X - A -> X + (-A)
-			{Instruction::SUB, {X, A}},
-			[=]() -> Pattern { return {Instruction::ADD, {X, 0 - A.d()}}; }
-		}, {
-			// (X + A) - Y -> (X - Y) + A
-			{Instruction::SUB, {{Instruction::ADD, {X, A}}, Y}},
-			[=]() -> Pattern { return {Instruction::ADD, {{Instruction::SUB, {X, Y}}, A}}; }
-		}, {
-			// (A + X) - Y -> (X - Y) + A
-			{Instruction::SUB, {{Instruction::ADD, {A, X}}, Y}},
-			[=]() -> Pattern { return {Instruction::ADD, {{Instruction::SUB, {X, Y}}, A}}; }
-		}, {
-			// X - (Y + A) -> (X - Y) + (-A)
-			{Instruction::SUB, {X, {Instruction::ADD, {Y, A}}}},
-			[=]() -> Pattern { return {Instruction::ADD, {{Instruction::SUB, {X, Y}}, 0 - A.d()}}; }
-		}, {
-			// X - (A + Y) -> (X - Y) + (-A)
-			{Instruction::SUB, {X, {Instruction::ADD, {A, Y}}}},
-			[=]() -> Pattern { return {Instruction::ADD, {{Instruction::SUB, {X, Y}}, 0 - A.d()}}; }
-		}
-	};
-}
-
 ExpressionClasses::Id ExpressionClasses::tryToSimplify(Expression const& _expr, bool _secondRun)
 {
 	static Rules rules;
@@ -376,21 +192,17 @@ ExpressionClasses::Id ExpressionClasses::tryToSimplify(Expression const& _expr,
 	)
 		return -1;
 
-	for (auto const& rule: rules.rules())
+	if (auto match = rules.findFirstMatch(_expr, *this))
 	{
-		rules.resetMatchGroups();
-		if (rule.first.matches(_expr, *this))
-		{
-			// Debug info
-			//cout << "Simplifying " << *_expr.item << "(";
-			//for (Id arg: _expr.arguments)
-			//	cout << fullDAGToString(arg) << ", ";
-			//cout << ")" << endl;
-			//cout << "with rule " << rule.first.toString() << endl;
-			//ExpressionTemplate t(rule.second());
-			//cout << "to " << rule.second().toString() << endl;
-			return rebuildExpression(ExpressionTemplate(rule.second(), _expr.item->location()));
-		}
+		// Debug info
+		//cout << "Simplifying " << *_expr.item << "(";
+		//for (Id arg: _expr.arguments)
+		//	cout << fullDAGToString(arg) << ", ";
+		//cout << ")" << endl;
+		//cout << "with rule " << match->first.toString() << endl;
+		//ExpressionTemplate t(match->second());
+		//cout << "to " << match->second().toString() << endl;
+		return rebuildExpression(ExpressionTemplate(match->second(), _expr.item->location()));
 	}
 
 	if (!_secondRun && _expr.arguments.size() == 2 && SemanticInformation::isCommutativeOperation(*_expr.item))
@@ -413,131 +225,3 @@ ExpressionClasses::Id ExpressionClasses::rebuildExpression(ExpressionTemplate co
 		arguments.push_back(rebuildExpression(t));
 	return find(_template.item, arguments);
 }
-
-
-Pattern::Pattern(Instruction _instruction, std::vector<Pattern> const& _arguments):
-	m_type(Operation),
-	m_instruction(_instruction),
-	m_arguments(_arguments)
-{
-}
-
-void Pattern::setMatchGroup(unsigned _group, map<unsigned, Expression const*>& _matchGroups)
-{
-	m_matchGroup = _group;
-	m_matchGroups = &_matchGroups;
-}
-
-bool Pattern::matches(Expression const& _expr, ExpressionClasses const& _classes) const
-{
-	if (!matchesBaseItem(_expr.item))
-		return false;
-	if (m_matchGroup)
-	{
-		if (!m_matchGroups->count(m_matchGroup))
-			(*m_matchGroups)[m_matchGroup] = &_expr;
-		else if ((*m_matchGroups)[m_matchGroup]->id != _expr.id)
-			return false;
-	}
-	assertThrow(m_arguments.size() == 0 || _expr.arguments.size() == m_arguments.size(), OptimizerException, "");
-	for (size_t i = 0; i < m_arguments.size(); ++i)
-		if (!m_arguments[i].matches(_classes.representative(_expr.arguments[i]), _classes))
-			return false;
-	return true;
-}
-
-AssemblyItem Pattern::toAssemblyItem(SourceLocation const& _location) const
-{
-	if (m_type == Operation)
-		return AssemblyItem(m_instruction, _location);
-	else
-		return AssemblyItem(m_type, data(), _location);
-}
-
-string Pattern::toString() const
-{
-	stringstream s;
-	switch (m_type)
-	{
-	case Operation:
-		s << instructionInfo(m_instruction).name;
-		break;
-	case Push:
-		s << "PUSH " << hex << data();
-		break;
-	case UndefinedItem:
-		s << "ANY";
-		break;
-	default:
-		s << "t=" << dec << m_type << " d=" << hex << data();
-		break;
-	}
-	if (!m_requireDataMatch)
-		s << " ~";
-	if (m_matchGroup)
-		s << "[" << dec << m_matchGroup << "]";
-	s << "(";
-	for (Pattern const& p: m_arguments)
-		s << p.toString() << ", ";
-	s << ")";
-	return s.str();
-}
-
-bool Pattern::matchesBaseItem(AssemblyItem const* _item) const
-{
-	if (m_type == UndefinedItem)
-		return true;
-	if (!_item)
-		return false;
-	if (m_type != _item->type())
-		return false;
-	else if (m_type == Operation)
-		return m_instruction == _item->instruction();
-	else if (m_requireDataMatch)
-		return data() == _item->data();
-	return true;
-}
-
-Pattern::Expression const& Pattern::matchGroupValue() const
-{
-	assertThrow(m_matchGroup > 0, OptimizerException, "");
-	assertThrow(!!m_matchGroups, OptimizerException, "");
-	assertThrow((*m_matchGroups)[m_matchGroup], OptimizerException, "");
-	return *(*m_matchGroups)[m_matchGroup];
-}
-
-u256 const& Pattern::data() const
-{
-	assertThrow(m_data, OptimizerException, "");
-	return *m_data;
-}
-
-ExpressionTemplate::ExpressionTemplate(Pattern const& _pattern, SourceLocation const& _location)
-{
-	if (_pattern.matchGroup())
-	{
-		hasId = true;
-		id = _pattern.id();
-	}
-	else
-	{
-		hasId = false;
-		item = _pattern.toAssemblyItem(_location);
-	}
-	for (auto const& arg: _pattern.arguments())
-		arguments.push_back(ExpressionTemplate(arg, _location));
-}
-
-string ExpressionTemplate::toString() const
-{
-	stringstream s;
-	if (hasId)
-		s << id;
-	else
-		s << item;
-	s << "(";
-	for (auto const& arg: arguments)
-		s << arg.toString();
-	s << ")";
-	return s.str();
-}