Prevent instructions to be generated as names.

libyul/AsmParser.cpp

@@ -53,6 +53,27 @@ shared_ptr<Block> Parser::parse(std::shared_ptr<Scanner> const& _scanner, bool _
 	return nullptr;
 }
 
+std::map<string, dev::eth::Instruction> const& Parser::instructions()
+{
+	// Allowed instructions, lowercase names.
+	static map<string, dev::eth::Instruction> s_instructions;
+	if (s_instructions.empty())
+	{
+		for (auto const& instruction: dev::eth::c_instructions)
+		{
+			if (
+				instruction.second == dev::eth::Instruction::JUMPDEST ||
+				dev::eth::isPushInstruction(instruction.second)
+			)
+				continue;
+			string name = instruction.first;
+			transform(name.begin(), name.end(), name.begin(), [](unsigned char _c) { return tolower(_c); });
+			s_instructions[name] = instruction.second;
+		}
+	}
+	return s_instructions;
+}
+
 Block Parser::parseBlock()
 {
 	RecursionGuard recursionGuard(*this);
@@ -340,27 +361,6 @@ Expression Parser::parseExpression()
 	}
 }
 
-std::map<string, dev::eth::Instruction> const& Parser::instructions()
-{
-	// Allowed instructions, lowercase names.
-	static map<string, dev::eth::Instruction> s_instructions;
-	if (s_instructions.empty())
-	{
-		for (auto const& instruction: dev::eth::c_instructions)
-		{
-			if (
-				instruction.second == dev::eth::Instruction::JUMPDEST ||
-				dev::eth::isPushInstruction(instruction.second)
-			)
-				continue;
-			string name = instruction.first;
-			transform(name.begin(), name.end(), name.begin(), [](unsigned char _c) { return tolower(_c); });
-			s_instructions[name] = instruction.second;
-		}
-	}
-	return s_instructions;
-}
-
 std::map<dev::eth::Instruction, string> const& Parser::instructionNames()
 {
 	static map<dev::eth::Instruction, string> s_instructionNames;

libyul/AsmParser.h

@@ -46,6 +46,9 @@ public:
 	/// @returns an empty shared pointer on error.
 	std::shared_ptr<Block> parse(std::shared_ptr<langutil::Scanner> const& _scanner, bool _reuseScanner);
 
+	/// @returns a map of all EVM instructions available to assembly.
+	static std::map<std::string, dev::eth::Instruction> const& instructions();
+
 protected:
 	using ElementaryOperation = boost::variant<Instruction, Literal, Identifier>;
 
@@ -71,7 +74,6 @@ protected:
 	ForLoop parseForLoop();
 	/// Parses a functional expression that has to push exactly one stack element
 	Expression parseExpression();
-	static std::map<std::string, dev::eth::Instruction> const& instructions();
 	static std::map<dev::eth::Instruction, std::string> const& instructionNames();
 	/// Parses an elementary operation, i.e. a literal, identifier or instruction.
 	/// This will parse instructions even in strict mode as part of the full parser

libyul/optimiser/NameDispenser.cpp

@@ -23,6 +23,10 @@
 #include <libyul/optimiser/NameCollector.h>
 #include <libyul/AsmData.h>
 #include <libyul/Dialect.h>
+#include <libyul/backends/evm/EVMDialect.h>
+#include <libyul/AsmParser.h>
+
+#include <libevmasm/Instruction.h>
 
 using namespace std;
 using namespace dev;
@@ -42,7 +46,7 @@ NameDispenser::NameDispenser(Dialect const& _dialect, set<YulString> _usedNames)
 YulString NameDispenser::newName(YulString _nameHint)
 {
 	YulString name = _nameHint;
-	while (name.empty() || m_usedNames.count(name) || m_dialect.builtin(name))
+	while (illegalName(name))
 	{
 		m_counter++;
 		name = YulString(_nameHint.str() + "_" + to_string(m_counter));
@@ -50,3 +54,12 @@ YulString NameDispenser::newName(YulString _nameHint)
 	m_usedNames.emplace(name);
 	return name;
 }
+
+bool NameDispenser::illegalName(YulString _name)
+{
+	if (_name.empty() || m_usedNames.count(_name) || m_dialect.builtin(_name))
+		return true;
+	if (dynamic_cast<EVMDialect const*>(&m_dialect))
+		return Parser::instructions().count(_name.str());
+	return false;
+}

libyul/optimiser/NameDispenser.h

@@ -47,6 +47,7 @@ public:
 	YulString newName(YulString _nameHint);
 
 private:
+	bool illegalName(YulString _name);
 
 	Dialect const& m_dialect;
 	std::set<YulString> m_usedNames;

libyul/optimiser/VarNameCleaner.cpp

@@ -18,6 +18,8 @@
 #include <libyul/optimiser/VarNameCleaner.h>
 #include <libyul/AsmData.h>
 #include <libyul/Dialect.h>
+#include <libyul/AsmParser.h>
+#include <libyul/backends/evm/EVMDialect.h>
 #include <algorithm>
 #include <cctype>
 #include <climits>
@@ -93,7 +95,7 @@ void VarNameCleaner::operator()(Identifier& _identifier)
 YulString VarNameCleaner::findCleanName(YulString const& _name) const
 {
 	auto newName = stripSuffix(_name);
-	if (newName != YulString{} && !isUsedName(newName))
+	if (!isUsedName(newName))
 		return newName;
 
 	// create new name with suffix (by finding a free identifier)
@@ -108,7 +110,11 @@ YulString VarNameCleaner::findCleanName(YulString const& _name) const
 
 bool VarNameCleaner::isUsedName(YulString const& _name) const
 {
-	return m_dialect.builtin(_name) || m_usedNames.count(_name);
+	if (_name.empty() || m_dialect.builtin(_name) || m_usedNames.count(_name))
+		return true;
+	if (dynamic_cast<EVMDialect const*>(&m_dialect))
+		return Parser::instructions().count(_name.str());
+	return false;
 }
 
 YulString VarNameCleaner::stripSuffix(YulString const& _name) const

test/libyul/yulOptimizerTests/varNameCleaner/instructions.yul

@@ -0,0 +1,9 @@
+{
+	let mul_256 := 1
+}
+// ====
+// step: varNameCleaner
+// ----
+// {
+//     let mul_1 := 1
+// }