SSACFG backend: add stack abstraction

Author: clonker

libyul/CMakeLists.txt

@@ -88,8 +88,10 @@ add_library(yul
 	backends/evm/ssa/SSACFG.h
 	backends/evm/ssa/SSACFGBuilder.cpp
 	backends/evm/ssa/SSACFGBuilder.h
-	backends/evm/ssa/SSACFGJsonExporter.h
 	backends/evm/ssa/SSACFGJsonExporter.cpp
+	backends/evm/ssa/SSACFGJsonExporter.h
+	backends/evm/ssa/Stack.cpp
+	backends/evm/ssa/Stack.h
 	optimiser/ASTCopier.cpp
 	optimiser/ASTCopier.h
 	optimiser/ASTWalker.cpp

libyul/backends/evm/ssa/Stack.cpp

@@ -0,0 +1,102 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+// SPDX-License-Identifier: GPL-3.0
+
+#include <libyul/backends/evm/ssa/Stack.h>
+
+#include <fmt/ranges.h>
+
+#include <range/v3/view/drop.hpp>
+
+namespace
+{
+size_t junkTailSize(solidity::yul::ssa::StackData const& _stackData)
+{
+	std::size_t numJunk = 0;
+	auto it = _stackData.begin();
+	while (it != _stackData.end() && it->isJunk())
+	{
+		++numJunk;
+		++it;
+	}
+	return numJunk;
+}
+}
+
+namespace solidity::yul::ssa
+{
+
+std::string slotToString(StackSlot const& _slot)
+{
+	switch (_slot.kind())
+	{
+	case StackSlot::Kind::ValueID:
+		if (_slot.isLiteralValueID())
+			return fmt::format("lit{}", _slot.valueID().value());
+		else
+			return fmt::format("v{}", _slot.valueID().value());
+	case StackSlot::Kind::Junk:
+		return "JUNK";
+	case StackSlot::Kind::FunctionCallReturnLabel:
+		return fmt::format("FunctionCallReturnLabel[{}]", _slot.functionCallReturnLabel());
+	case StackSlot::Kind::FunctionReturnLabel:
+		return fmt::format("ReturnLabel[{}]", _slot.functionReturnLabel());
+	}
+	util::unreachable();
+}
+
+std::string slotToString(StackSlot const& _slot, SSACFG const& _cfg)
+{
+	if (_slot.kind() == StackSlot::Kind::ValueID)
+		return _slot.valueID().str(_cfg);
+
+	return slotToString(_slot);
+}
+
+std::string stackToString(StackData const& _stackData)
+{
+	auto const numJunk = junkTailSize(_stackData);
+	if (numJunk > 0)
+		return fmt::format(
+			"[JUNK x {}, {}]",
+			numJunk,
+			fmt::join(_stackData | ranges::views::drop(numJunk) | ranges::views::transform([&](auto const& _slot) { return slotToString(_slot); }), ", ")
+		);
+
+	return fmt::format(
+		"[{}]",
+		fmt::join(_stackData | ranges::views::transform([&](auto const& _slot) { return slotToString(_slot); }), ", ")
+	);
+}
+
+std::string stackToString(StackData const& _stackData, SSACFG const& _cfg)
+{
+	auto const numJunk = junkTailSize(_stackData);
+	if (numJunk > 0)
+		return fmt::format(
+			"[JUNK x {}, {}]",
+			numJunk,
+			fmt::join(_stackData | ranges::views::drop(numJunk) | ranges::views::transform([&](auto const& _slot) { return slotToString(_slot, _cfg); }), ", ")
+		);
+
+	return fmt::format(
+		"[{}]",
+		fmt::join(_stackData | ranges::views::transform([&](auto const& _slot) { return slotToString(_slot, _cfg); }), ", ")
+	);
+}
+
+}