Add new Peephole Optimiser method (deduplicateNextTag)

ethereum · Jun 27, 2024 · 9b1792f · 9b1792f
1 parent ff12e94
commit 9b1792f
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Showing 4 changed files with 179 additions and 3 deletions.
diff --git a/libevmasm/PeepholeOptimiser.cpp b/libevmasm/PeepholeOptimiser.cpp
@@ -198,7 +198,7 @@ struct DoubleSwap: SimplePeepholeOptimizerMethod<DoubleSwap>
 	}
 };
 
-struct DoublePush: SimplePeepholeOptimizerMethod<DoublePush>
+struct DoublePush
 {
 	static bool apply(OptimiserState& _state)
 	{
@@ -498,6 +498,99 @@ struct UnreachableCode
 	}
 };
 
+struct DeduplicateNextTagSize3 : SimplePeepholeOptimizerMethod<DeduplicateNextTagSize3>
+{
+	static bool applySimple(
+		AssemblyItem const& _precedingItem,
+		AssemblyItem const& _itemA,
+		AssemblyItem const& _itemB,
+		AssemblyItem const& _breakingItem,
+		AssemblyItem const& _tag,
+		AssemblyItem const& _itemC,
+		AssemblyItem const& _itemD,
+		AssemblyItem const& _breakingItem2,
+		std::back_insert_iterator<AssemblyItems> _out
+	)
+	{
+		if (
+			_precedingItem.type() != Tag &&
+			_itemA == _itemC &&
+			_itemB == _itemD &&
+			_breakingItem == _breakingItem2 &&
+			_tag.type() == Tag &&
+			SemanticInformation::terminatesControlFlow(_breakingItem)
+		)
+		{
+			*_out = _precedingItem;
+			*_out = _tag;
+			*_out = _itemC;
+			*_out = _itemD;
+			*_out = _breakingItem2;
+			return true;
+		}
+
+		return false;
+	}
+};
+
+struct DeduplicateNextTagSize2 : SimplePeepholeOptimizerMethod<DeduplicateNextTagSize2>
+{
+	static bool applySimple(
+		AssemblyItem const& _precedingItem,
+		AssemblyItem const& _itemA,
+		AssemblyItem const& _breakingItem,
+		AssemblyItem const& _tag,
+		AssemblyItem const& _itemC,
+		AssemblyItem const& _breakingItem2,
+		std::back_insert_iterator<AssemblyItems> _out
+	)
+	{
+		if (
+			_precedingItem.type() != Tag &&
+			_itemA == _itemC &&
+			_breakingItem == _breakingItem2 &&
+			_tag.type() == Tag &&
+			SemanticInformation::terminatesControlFlow(_breakingItem)
+		)
+		{
+			*_out = _precedingItem;
+			*_out = _tag;
+			*_out = _itemC;
+			*_out = _breakingItem2;
+			return true;
+		}
+
+		return false;
+	}
+};
+
+struct DeduplicateNextTagSize1 : SimplePeepholeOptimizerMethod<DeduplicateNextTagSize1>
+{
+	static bool applySimple(
+		AssemblyItem const& _precedingItem,
+		AssemblyItem const& _breakingItem,
+		AssemblyItem const& _tag,
+		AssemblyItem const& _breakingItem2,
+		std::back_insert_iterator<AssemblyItems> _out
+	)
+	{
+		if (
+			_precedingItem.type() != Tag &&
+			_breakingItem == _breakingItem2 &&
+			_tag.type() == Tag &&
+			SemanticInformation::terminatesControlFlow(_breakingItem)
+		)
+		{
+			*_out = _precedingItem;
+			*_out = _tag;
+			*_out = _breakingItem2;
+			return true;
+		}
+
+		return false;
+	}
+};
+
 void applyMethods(OptimiserState&)
 {
 	assertThrow(false, OptimizerException, "Peephole optimizer failed to apply identity.");
@@ -526,8 +619,8 @@ bool PeepholeOptimiser::optimise()
 		applyMethods(
 			state,
 			PushPop(), OpPop(), OpStop(), OpReturnRevert(), DoublePush(), DoubleSwap(), CommutativeSwap(), SwapComparison(),
-			DupSwap(), IsZeroIsZeroJumpI(), EqIsZeroJumpI(), DoubleJump(), JumpToNext(), UnreachableCode(),
-			TagConjunctions(), TruthyAnd(), Identity()
+			DupSwap(), IsZeroIsZeroJumpI(), EqIsZeroJumpI(), DoubleJump(), JumpToNext(), UnreachableCode(), DeduplicateNextTagSize3(),
+			DeduplicateNextTagSize2(), DeduplicateNextTagSize1(), TagConjunctions(), TruthyAnd(), Identity()
 		);
 	if (m_optimisedItems.size() < m_items.size() || (
 		m_optimisedItems.size() == m_items.size() && (

diff --git a/libevmasm/SemanticInformation.cpp b/libevmasm/SemanticInformation.cpp
@@ -299,6 +299,13 @@ bool SemanticInformation::altersControlFlow(AssemblyItem const& _item)
 	}
 }
 
+bool SemanticInformation::terminatesControlFlow(AssemblyItem const& _item)
+{
+	if (_item.type() != evmasm::Operation)
+		return false;
+	return terminatesControlFlow(_item.instruction());
+}
+
 bool SemanticInformation::terminatesControlFlow(Instruction _instruction)
 {
 	switch (_instruction)

diff --git a/libevmasm/SemanticInformation.h b/libevmasm/SemanticInformation.h
@@ -84,6 +84,7 @@ struct SemanticInformation
 	static bool isSwapInstruction(AssemblyItem const& _item);
 	static bool isJumpInstruction(AssemblyItem const& _item);
 	static bool altersControlFlow(AssemblyItem const& _item);
+	static bool terminatesControlFlow(AssemblyItem const& _item);
 	static bool terminatesControlFlow(Instruction _instruction);
 	static bool reverts(Instruction _instruction);
 	/// @returns false if the value put on the stack by _item depends on anything else than

diff --git a/test/libevmasm/Optimiser.cpp b/test/libevmasm/Optimiser.cpp
@@ -1008,6 +1008,81 @@ BOOST_AUTO_TEST_CASE(clear_unreachable_code)
 	);
 }
 
+BOOST_AUTO_TEST_CASE(deduplicateNextTagBlockSize3)
+{
+	AssemblyItems items{
+		Instruction::JUMP,
+		u256(0),
+		u256(1),
+		Instruction::REVERT,
+		AssemblyItem(Tag, 2),
+		u256(0),
+		u256(1),
+		Instruction::REVERT
+	};
+
+	AssemblyItems expectation{
+		Instruction::JUMP,
+		AssemblyItem(Tag, 2),
+		u256(0),
+		u256(1),
+		Instruction::REVERT
+	};
+	PeepholeOptimiser peepOpt(items, solidity::test::CommonOptions::get().evmVersion());
+	BOOST_REQUIRE(peepOpt.optimise());
+	BOOST_CHECK_EQUAL_COLLECTIONS(
+		items.begin(), items.end(),
+		expectation.begin(), expectation.end()
+	);
+}
+
+BOOST_AUTO_TEST_CASE(deduplicateNextTagBlockSize2)
+{
+	AssemblyItems items{
+		Instruction::JUMP,
+		u256(0),
+		Instruction::SELFDESTRUCT,
+		AssemblyItem(Tag, 2),
+		u256(0),
+		Instruction::SELFDESTRUCT
+	};
+
+	AssemblyItems expectation{
+		Instruction::JUMP,
+		AssemblyItem(Tag, 2),
+		u256(0),
+		Instruction::SELFDESTRUCT
+	};
+	PeepholeOptimiser peepOpt(items, solidity::test::CommonOptions::get().evmVersion());
+	BOOST_REQUIRE(peepOpt.optimise());
+	BOOST_CHECK_EQUAL_COLLECTIONS(
+		items.begin(), items.end(),
+		expectation.begin(), expectation.end()
+	);
+}
+
+BOOST_AUTO_TEST_CASE(deduplicateNextTagBlockSize1)
+{
+	AssemblyItems items{
+		Instruction::JUMP,
+		Instruction::STOP,
+		AssemblyItem(Tag, 2),
+		Instruction::STOP
+	};
+
+	AssemblyItems expectation{
+		Instruction::JUMP,
+		AssemblyItem(Tag, 2),
+		Instruction::STOP
+	};
+	PeepholeOptimiser peepOpt(items, solidity::test::CommonOptions::get().evmVersion());
+	BOOST_REQUIRE(peepOpt.optimise());
+	BOOST_CHECK_EQUAL_COLLECTIONS(
+		items.begin(), items.end(),
+		expectation.begin(), expectation.end()
+	);
+}
+
 BOOST_AUTO_TEST_CASE(peephole_double_push)
 {
 	AssemblyItems items{