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Merge pull request #7408 from ethereum/literalRematerializer

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[Yul] Introduce LiteralRematerializer and thus simplify StructuralSimplifier.
This commit is contained in:
chriseth 2019-09-12 00:56:45 +02:00 committed by GitHub
commit 324cc71b13
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10 changed files with 152 additions and 145 deletions
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21
libyul/optimiser/Rematerialiser.cpp
View File

@ -71,9 +71,9 @@ void Rematerialiser::visit(Expression& _e)
if (_e.type() == typeid(Identifier))
{
Identifier& identifier = boost::get<Identifier>(_e);
if (m_value.count(identifier.name))
{
YulString name = identifier.name;
if (m_value.count(name))
{
assertThrow(m_value.at(name), OptimizerException, "");
auto const& value = *m_value.at(name);
size_t refs = m_referenceCounts[name];
@ -93,3 +93,20 @@ void Rematerialiser::visit(Expression& _e)
}
DataFlowAnalyzer::visit(_e);
}
void LiteralRematerialiser::visit(Expression& _e)
{
if (_e.type() == typeid(Identifier))
{
Identifier& identifier = boost::get<Identifier>(_e);
YulString name = identifier.name;
if (m_value.count(name))
{
Expression const* value = m_value.at(name);
assertThrow(value, OptimizerException, "");
if (value->type() == typeid(Literal))
_e = *value;
}
}
DataFlowAnalyzer::visit(_e);
}

21
libyul/optimiser/Rematerialiser.h
View File

@ -68,4 +68,25 @@ protected:
std::set<YulString> m_varsToAlwaysRematerialize;
};
/**
* If a variable is referenced that is known to have a literal
* value at that point, replace it by a literal.
*
* This is mostly used so that other components do not have to rely
* on the data flow analyzer.
*
* Prerequisite: Disambiguator, ForLoopInitRewriter.
*/
class LiteralRematerialiser: public DataFlowAnalyzer
{
public:
LiteralRematerialiser(Dialect const& _dialect):
DataFlowAnalyzer(_dialect)
{}
using ASTModifier::visit;
void visit(Expression& _e) override;
};
}

60
libyul/optimiser/StructuralSimplifier.cpp
View File

@ -61,29 +61,7 @@ OptionalStatements replaceConstArgSwitch(Switch& _switchStmt, u256 const& _const
void StructuralSimplifier::operator()(Block& _block)
{
pushScope(false);
simplify(_block.statements);
popScope();
}
boost::optional<dev::u256> StructuralSimplifier::hasLiteralValue(Expression const& _expression) const
{
Expression const* expr = &_expression;
if (expr->type() == typeid(Identifier))
{
Identifier const& ident = boost::get<Identifier>(*expr);
if (m_value.count(ident.name))
expr = m_value.at(ident.name);
}
if (expr && expr->type() == typeid(Literal))
{
Literal const& literal = boost::get<Literal>(*expr);
return valueOfLiteral(literal);
}
return boost::optional<u256>();
}
void StructuralSimplifier::simplify(std::vector<yul::Statement>& _statements)
@ -124,34 +102,24 @@ void StructuralSimplifier::simplify(std::vector<yul::Statement>& _statements)
bool StructuralSimplifier::expressionAlwaysTrue(Expression const& _expression)
{
return boost::apply_visitor(GenericFallbackReturnsVisitor<bool, Identifier const, Literal const>(
[&](Identifier const& _identifier) -> bool {
if (auto expr = m_value[_identifier.name])
return expressionAlwaysTrue(*expr);
if (boost::optional<u256> value = hasLiteralValue(_expression))
return *value != 0;
else
return false;
},
[](Literal const& _literal) -> bool {
return
(_literal.kind == LiteralKind::Boolean && _literal.value == "true"_yulstring) ||
(_literal.kind == LiteralKind::Number && valueOfNumberLiteral(_literal) != u256(0))
;
}
), _expression);
}
bool StructuralSimplifier::expressionAlwaysFalse(Expression const& _expression)
{
return boost::apply_visitor(GenericFallbackReturnsVisitor<bool, Identifier const, Literal const>(
[&](Identifier const& _identifier) -> bool {
if (auto expr = m_value[_identifier.name])
return expressionAlwaysFalse(*expr);
if (boost::optional<u256> value = hasLiteralValue(_expression))
return *value == 0;
else
return false;
},
[](Literal const& _literal) -> bool {
return
(_literal.kind == LiteralKind::Boolean && _literal.value == "false"_yulstring) ||
(_literal.kind == LiteralKind::Number && valueOfNumberLiteral(_literal) == u256(0))
;
}
), _expression);
}
boost::optional<dev::u256> StructuralSimplifier::hasLiteralValue(Expression const& _expression) const
{
if (_expression.type() == typeid(Literal))
return valueOfLiteral(boost::get<Literal>(_expression));
else
return boost::optional<u256>();
}

10
libyul/optimiser/StructuralSimplifier.h
View File

@ -30,16 +30,16 @@ namespace yul
* - replace switch with const expr with matching case body
* - replace for with false condition by its initialization part
*
* Prerequisite: Disambiguator, ForLoopInitRewriter.
* The LiteralRematerialiser should be run before this.
*
* Prerequisite: Disambiguator.
*
* Important: Can only be used on EVM code.
*/
class StructuralSimplifier: public DataFlowAnalyzer
class StructuralSimplifier: public ASTModifier
{
public:
explicit StructuralSimplifier(Dialect const& _dialect): DataFlowAnalyzer(_dialect) {}
using DataFlowAnalyzer::operator();
using ASTModifier::operator();
void operator()(Block& _block) override;
private:
void simplify(std::vector<Statement>& _statements);

9
libyul/optimiser/Suite.cpp
View File

@ -91,7 +91,8 @@ void OptimiserSuite::run(
UnusedPruner::runUntilStabilisedOnFullAST(_dialect, ast, reservedIdentifiers);
BlockFlattener{}(ast);
ControlFlowSimplifier{_dialect}(ast);
StructuralSimplifier{_dialect}(ast);
LiteralRematerialiser{_dialect}(ast);
StructuralSimplifier{}(ast);
ControlFlowSimplifier{_dialect}(ast);
BlockFlattener{}(ast);
@ -125,7 +126,8 @@ void OptimiserSuite::run(
{
// still in SSA, perform structural simplification
ControlFlowSimplifier{_dialect}(ast);
StructuralSimplifier{_dialect}(ast);
LiteralRematerialiser{_dialect}(ast);
StructuralSimplifier{}(ast);
ControlFlowSimplifier{_dialect}(ast);
BlockFlattener{}(ast);
DeadCodeEliminator{_dialect}(ast);
@ -182,7 +184,8 @@ void OptimiserSuite::run(
RedundantAssignEliminator::run(_dialect, ast);
LoadResolver::run(_dialect, ast);
ExpressionSimplifier::run(_dialect, ast);
StructuralSimplifier{_dialect}(ast);
LiteralRematerialiser{_dialect}(ast);
StructuralSimplifier{}(ast);
BlockFlattener{}(ast);
DeadCodeEliminator{_dialect}(ast);
ControlFlowSimplifier{_dialect}(ast);

54
test/cmdlineTests/yul_stack_opt/output
View File

@ -11,20 +11,20 @@ object "object" {
}
function fun() -> a3, b3, c3, d3, e3, f3, g3, h3, i3, j3, k3, l3, m3, n3, o3, p3
{
let a := 1
sstore(a, a)
sstore(2, a)
sstore(3, a)
sstore(4, a)
sstore(5, a)
sstore(6, a)
sstore(7, a)
sstore(8, a)
sstore(9, a)
sstore(10, a)
sstore(11, a)
sstore(12, a)
sstore(13, a)
let _1 := 1
sstore(_1, _1)
sstore(2, _1)
sstore(3, _1)
sstore(4, _1)
sstore(5, _1)
sstore(6, _1)
sstore(7, _1)
sstore(8, _1)
sstore(9, _1)
sstore(10, _1)
sstore(11, _1)
sstore(12, _1)
sstore(13, _1)
}
}
}
@ -103,79 +103,77 @@ tag_2:
0x00
/* "yul_stack_opt/input.sol":98:99 */
0x01
/* "yul_stack_opt/input.sol":139:140 */
dup1
/* "yul_stack_opt/input.sol":136:137 */
dup2
/* "yul_stack_opt/input.sol":129:141 */
sstore
/* "yul_stack_opt/input.sol":162:163 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":151:160 */
0x02
/* "yul_stack_opt/input.sol":144:164 */
sstore
/* "yul_stack_opt/input.sol":185:186 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":174:183 */
0x03
/* "yul_stack_opt/input.sol":167:187 */
sstore
/* "yul_stack_opt/input.sol":208:209 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":197:206 */
0x04
/* "yul_stack_opt/input.sol":190:210 */
sstore
/* "yul_stack_opt/input.sol":231:232 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":220:229 */
0x05
/* "yul_stack_opt/input.sol":213:233 */
sstore
/* "yul_stack_opt/input.sol":254:255 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":243:252 */
0x06
/* "yul_stack_opt/input.sol":236:256 */
sstore
/* "yul_stack_opt/input.sol":277:278 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":266:275 */
0x07
/* "yul_stack_opt/input.sol":259:279 */
sstore
/* "yul_stack_opt/input.sol":300:301 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":289:298 */
0x08
/* "yul_stack_opt/input.sol":282:302 */
sstore
/* "yul_stack_opt/input.sol":323:324 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":312:321 */
0x09
/* "yul_stack_opt/input.sol":305:325 */
sstore
/* "yul_stack_opt/input.sol":346:347 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":335:344 */
0x0a
/* "yul_stack_opt/input.sol":328:348 */
sstore
/* "yul_stack_opt/input.sol":370:371 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":358:368 */
0x0b
/* "yul_stack_opt/input.sol":351:372 */
sstore
/* "yul_stack_opt/input.sol":394:395 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":382:392 */
0x0c
/* "yul_stack_opt/input.sol":375:396 */
sstore
/* "yul_stack_opt/input.sol":418:419 */
/* "yul_stack_opt/input.sol":98:99 */
dup1
/* "yul_stack_opt/input.sol":406:416 */
0x0d

4
test/libyul/YulOptimizerTest.cpp
View File

@ -279,7 +279,9 @@ TestCase::TestResult YulOptimizerTest::run(ostream& _stream, string const& _line
else if (m_optimizerStep == "structuralSimplifier")
{
disambiguate();
StructuralSimplifier{*m_dialect}(*m_ast);
ForLoopInitRewriter{}(*m_ast);
LiteralRematerialiser{*m_dialect}(*m_ast);
StructuralSimplifier{}(*m_ast);
}
else if (m_optimizerStep == "equivalentFunctionCombiner")
{

42
test/libyul/yulOptimizerTests/fullSuite/abi_example1.yul
View File

@ -462,34 +462,34 @@
// ----
// {
// {
// let _1 := 0x20
// let _2 := 0
// let _3 := mload(_2)
// let pos := _1
// let length := mload(_3)
// mstore(_1, length)
// let _1 := 0
// let _2 := mload(_1)
// let pos := 0x20
// let pos_1 := pos
// let length := mload(_2)
// mstore(pos, length)
// pos := 64
// let srcPtr := add(_3, _1)
// let i := _2
// let srcPtr := add(_2, pos_1)
// let i := _1
// for { } lt(i, length) { i := add(i, 1) }
// {
// abi_encode_t_array$_t_contract$_C_$55_$3_memory_to_t_array$_t_address_$3_memory_ptr(mload(srcPtr), pos)
// srcPtr := add(srcPtr, _1)
// srcPtr := add(srcPtr, pos_1)
// pos := add(pos, 0x60)
// }
// let _4 := mload(64)
// let _5 := mload(_1)
// if slt(sub(_4, _5), 128) { revert(_2, _2) }
// let offset := calldataload(add(_5, 64))
// let _6 := 0xffffffffffffffff
// if gt(offset, _6) { revert(_2, _2) }
// let value2 := abi_decode_t_array$_t_uint256_$dyn_memory_ptr(add(_5, offset), _4)
// let offset_1 := calldataload(add(_5, 96))
// if gt(offset_1, _6) { revert(_2, _2) }
// let value3 := abi_decode_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(add(_5, offset_1), _4)
// sstore(calldataload(_5), calldataload(add(_5, _1)))
// let _3 := mload(64)
// let _4 := mload(pos_1)
// if slt(sub(_3, _4), 128) { revert(_1, _1) }
// let offset := calldataload(add(_4, 64))
// let _5 := 0xffffffffffffffff
// if gt(offset, _5) { revert(_1, _1) }
// let value2 := abi_decode_t_array$_t_uint256_$dyn_memory_ptr(add(_4, offset), _3)
// let offset_1 := calldataload(add(_4, 96))
// if gt(offset_1, _5) { revert(_1, _1) }
// let value3 := abi_decode_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(add(_4, offset_1), _3)
// sstore(calldataload(_4), calldataload(add(_4, pos_1)))
// sstore(value2, value3)
// sstore(_2, pos)
// sstore(_1, pos)
// }
// function abi_decode_t_array$_t_array$_t_uint256_$2_memory_$dyn_memory_ptr(offset, end) -> array
// {

70
test/libyul/yulOptimizerTests/fullSuite/aztec.yul
View File

@ -238,8 +238,8 @@
// let notes := add(0x04, calldataload(0x04))
// let m := calldataload(0x24)
// let n := calldataload(notes)
// let gen_order := 0x30644e72e131a029b85045b68181585d2833e84879b9709143e1f593f0000001
// let challenge := mod(calldataload(0x44), gen_order)
// let _1 := 0x30644e72e131a029b85045b68181585d2833e84879b9709143e1f593f0000001
// let challenge := mod(calldataload(0x44), _1)
// if gt(m, n)
// {
// mstore(0x00, 404)
@ -249,72 +249,70 @@
// mstore(0x2a0, caller())
// mstore(0x2c0, kn)
// mstore(0x2e0, m)
// kn := mulmod(sub(gen_order, kn), challenge, gen_order)
// kn := mulmod(sub(_1, kn), challenge, _1)
// hashCommitments(notes, n)
// let b := add(0x300, mul(n, 0x80))
// let i := 0
// let i_1 := i
// for { } lt(i, n) { i := add(i, 0x01) }
// {
// let _1 := add(calldataload(0x04), mul(i, 0xc0))
// let noteIndex := add(_1, 0x24)
// let _2 := add(calldataload(0x04), mul(i, 0xc0))
// let noteIndex := add(_2, 0x24)
// let k := i_1
// let a := calldataload(add(_1, 0x44))
// let a := calldataload(add(_2, 0x44))
// let c := challenge
// let _2 := add(i, 0x01)
// switch eq(_2, n)
// let _3 := add(i, 0x01)
// switch eq(_3, n)
// case 1 {
// k := kn
// if eq(m, n) { k := sub(gen_order, kn) }
// if eq(m, n) { k := sub(_1, kn) }
// }
// case 0 { k := calldataload(noteIndex) }
// validateCommitment(noteIndex, k, a)
// switch gt(_2, m)
// switch gt(_3, m)
// case 1 {
// kn := addmod(kn, sub(gen_order, k), gen_order)
// let x := mod(mload(i_1), gen_order)
// k := mulmod(k, x, gen_order)
// a := mulmod(a, x, gen_order)
// c := mulmod(challenge, x, gen_order)
// kn := addmod(kn, sub(_1, k), _1)
// let x := mod(mload(i_1), _1)
// k := mulmod(k, x, _1)
// a := mulmod(a, x, _1)
// c := mulmod(challenge, x, _1)
// mstore(i_1, keccak256(i_1, 0x20))
// }
// case 0 {
// kn := addmod(kn, k, gen_order)
// }
// let _3 := 0x40
// calldatacopy(0xe0, add(_1, 164), _3)
// calldatacopy(0x20, add(_1, 100), _3)
// mstore(0x120, sub(gen_order, c))
// case 0 { kn := addmod(kn, k, _1) }
// let _4 := 0x40
// calldatacopy(0xe0, add(_2, 164), _4)
// calldatacopy(0x20, add(_2, 100), _4)
// mstore(0x120, sub(_1, c))
// mstore(0x60, k)
// mstore(0xc0, a)
// let result := call(gas(), 7, i_1, 0xe0, 0x60, 0x1a0, _3)
// let result_1 := and(result, call(gas(), 7, i_1, 0x20, 0x60, 0x120, _3))
// let result_2 := and(result_1, call(gas(), 7, i_1, 0x80, 0x60, 0x160, _3))
// let result_3 := and(result_2, call(gas(), 6, i_1, 0x120, 0x80, 0x160, _3))
// result := and(result_3, call(gas(), 6, i_1, 0x160, 0x80, b, _3))
// let result := call(gas(), 7, i_1, 0xe0, 0x60, 0x1a0, _4)
// let result_1 := and(result, call(gas(), 7, i_1, 0x20, 0x60, 0x120, _4))
// let result_2 := and(result_1, call(gas(), 7, i_1, 0x80, 0x60, 0x160, _4))
// let result_3 := and(result_2, call(gas(), 6, i_1, 0x120, 0x80, 0x160, _4))
// result := and(result_3, call(gas(), 6, i_1, 0x160, 0x80, b, _4))
// if eq(i, m)
// {
// mstore(0x260, mload(0x20))
// mstore(0x280, mload(_3))
// mstore(0x280, mload(_4))
// mstore(0x1e0, mload(0xe0))
// mstore(0x200, sub(0x30644e72e131a029b85045b68181585d97816a916871ca8d3c208c16d87cfd47, mload(0x100)))
// }
// if gt(i, m)
// {
// mstore(0x60, c)
// let result_4 := and(result, call(gas(), 7, i_1, 0x20, 0x60, 0x220, _3))
// let result_5 := and(result_4, call(gas(), 6, i_1, 0x220, 0x80, 0x260, _3))
// result := and(result_5, call(gas(), 6, i_1, 0x1a0, 0x80, 0x1e0, _3))
// let result_4 := and(result, call(gas(), 7, i_1, 0x20, 0x60, 0x220, _4))
// let result_5 := and(result_4, call(gas(), 6, i_1, 0x220, 0x80, 0x260, _4))
// result := and(result_5, call(gas(), 6, i_1, 0x1a0, 0x80, 0x1e0, _4))
// }
// if iszero(result)
// {
// mstore(i_1, 400)
// revert(i_1, 0x20)
// }
// b := add(b, _3)
// b := add(b, _4)
// }
// if lt(m, n) { validatePairing(0x64) }
// if iszero(eq(mod(keccak256(0x2a0, add(b, not(671))), gen_order), challenge))
// if iszero(eq(mod(keccak256(0x2a0, add(b, not(671))), _1), challenge))
// {
// mstore(i_1, 404)
// revert(i_1, 0x20)
@ -360,13 +358,13 @@
// }
// function validateCommitment(note, k, a)
// {
// let gen_order := 0x30644e72e131a029b85045b68181585d2833e84879b9709143e1f593f0000001
// let field_order := 0x30644e72e131a029b85045b68181585d97816a916871ca8d3c208c16d87cfd47
// let gammaX := calldataload(add(note, 0x40))
// let gammaY := calldataload(add(note, 0x60))
// let sigmaX := calldataload(add(note, 0x80))
// let sigmaY := calldataload(add(note, 0xa0))
// if iszero(and(and(and(eq(mod(a, gen_order), a), gt(a, 1)), and(eq(mod(k, gen_order), k), gt(k, 1))), and(eq(addmod(mulmod(mulmod(sigmaX, sigmaX, field_order), sigmaX, field_order), 3, field_order), mulmod(sigmaY, sigmaY, field_order)), eq(addmod(mulmod(mulmod(gammaX, gammaX, field_order), gammaX, field_order), 3, field_order), mulmod(gammaY, gammaY, field_order)))))
// let _1 := 0x30644e72e131a029b85045b68181585d97816a916871ca8d3c208c16d87cfd47
// let _2 := 0x30644e72e131a029b85045b68181585d2833e84879b9709143e1f593f0000001
// if iszero(and(and(and(eq(mod(a, _2), a), gt(a, 1)), and(eq(mod(k, _2), k), gt(k, 1))), and(eq(addmod(mulmod(mulmod(sigmaX, sigmaX, _1), sigmaX, _1), 3, _1), mulmod(sigmaY, sigmaY, _1)), eq(addmod(mulmod(mulmod(gammaX, gammaX, _1), gammaX, _1), 3, _1), mulmod(gammaY, gammaY, _1)))))
// {
// mstore(0x00, 400)
// revert(0x00, 0x20)

2
test/tools/yulopti.cpp
View File

@ -184,7 +184,7 @@ public:
ExpressionSimplifier::run(m_dialect, *m_ast);
break;
case 't':
(StructuralSimplifier{m_dialect})(*m_ast);
StructuralSimplifier{}(*m_ast);
break;
case 'n':
(ControlFlowSimplifier{m_dialect})(*m_ast);