Merge pull request #5416 from ethereum/develop

Merge develop into release for 0.5.0

1 files changed, 62 insertions, 0 deletions

diff --git a/libyul/optimiser/NameDispenser.cpp b/libyul/optimiser/NameDispenser.cpp
new file mode 100644
index 00000000..3c870fa5
--- /dev/null
+++ b/libyul/optimiser/NameDispenser.cpp
@@ -0,0 +1,62 @@
+/*
+	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/>.
+*/
+/**
+ * Optimiser component that can create new unique names.
+ */
+
+#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;
+
+NameDispenser::NameDispenser(Block const& _ast):
+	NameDispenser(NameCollector(_ast).names())
+{
+}
+
+NameDispenser::NameDispenser(set<YulString> _usedNames):
+	m_usedNames(std::move(_usedNames))
+{
+}
+
+YulString NameDispenser::newName(YulString _nameHint, YulString _context)
+{
+	// Shortening rules: Use a suffix of _prefix and a prefix of _context.
+	YulString prefix = _nameHint;
+
+	if (!_context.empty())
+		prefix = YulString{_context.str().substr(0, 10) + "_" + prefix.str()};
+
+	return newNameInternal(prefix);
+}
+
+YulString NameDispenser::newNameInternal(YulString _nameHint)
+{
+	YulString name = _nameHint;
+	while (name.empty() || m_usedNames.count(name))
+	{
+		m_counter++;
+		name = YulString(_nameHint.str() + "_" + to_string(m_counter));
+	}
+	m_usedNames.emplace(name);
+	return name;
+}