From 15517b571d3ac4ee01af3e2e2f3fff7c5b2296c5 Mon Sep 17 00:00:00 2001
From: Alex Beregszaszi <alex@rtfs.hu>
Date: Fri, 13 Oct 2017 02:04:36 +0100
Subject: [PATCH] lll: disallow useless PUSHn in assembly

---
 liblll/CodeFragment.cpp  | 44 ++++++++++++++++++++++++----------------
 test/liblll/Compiler.cpp | 17 ++++++++++++++++
 2 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/liblll/CodeFragment.cpp b/liblll/CodeFragment.cpp
index d4ef38883dc2..5c68194b4205 100644
--- a/liblll/CodeFragment.cpp
+++ b/liblll/CodeFragment.cpp
@@ -47,6 +47,32 @@ void CodeFragment::finalise(CompilerState const& _cs)
 	}
 }
 
+namespace
+{
+/// Returns true iff the instruction is valid in "inline assembly".
+bool validAssemblyInstruction(string us)
+{
+	auto it = c_instructions.find(us);
+	return !(
+		it == c_instructions.end() ||
+		solidity::isPushInstruction(it->second)
+	);
+}
+
+/// Returns true iff the instruction is valid as a function.
+bool validFunctionalInstruction(string us)
+{
+	auto it = c_instructions.find(us);
+	return !(
+		it == c_instructions.end() ||
+		solidity::isPushInstruction(it->second) ||
+		solidity::isDupInstruction(it->second) ||
+		solidity::isSwapInstruction(it->second) ||
+		it->second == solidity::Instruction::JUMPDEST
+	);
+}
+}
+
 CodeFragment::CodeFragment(sp::utree const& _t, CompilerState& _s, ReadCallback const& _readFile, bool _allowASM):
 	m_readFile(_readFile)
 {
@@ -80,7 +106,7 @@ CodeFragment::CodeFragment(sp::utree const& _t, CompilerState& _s, ReadCallback
 		auto sr = _t.get<sp::basic_string<boost::iterator_range<char const*>, sp::utree_type::symbol_type>>();
 		string s(sr.begin(), sr.end());
 		string us = boost::algorithm::to_upper_copy(s);
-		if (_allowASM && c_instructions.count(us))
+		if (_allowASM && c_instructions.count(us) && validAssemblyInstruction(us))
 			m_asm.append(c_instructions.at(us));
 		else if (_s.defs.count(s))
 			m_asm.append(_s.defs.at(s).m_asm);
@@ -114,22 +140,6 @@ CodeFragment::CodeFragment(sp::utree const& _t, CompilerState& _s, ReadCallback
 	}
 }
 
-namespace
-{
-/// Returns true iff the instruction is valid as a function.
-bool validFunctionalInstruction(string us)
-{
-	auto it = c_instructions.find(us);
-	return !(
-		it == c_instructions.end() ||
-		solidity::isPushInstruction(it->second) ||
-		solidity::isDupInstruction(it->second) ||
-		solidity::isSwapInstruction(it->second) ||
-		it->second == solidity::Instruction::JUMPDEST
-	);
-}
-}
-
 void CodeFragment::constructOperation(sp::utree const& _t, CompilerState& _s)
 {
 	if (_t.tag() == 0 && _t.empty())
diff --git a/test/liblll/Compiler.cpp b/test/liblll/Compiler.cpp
index 2d66bce1fe4f..77d263b8d08c 100644
--- a/test/liblll/Compiler.cpp
+++ b/test/liblll/Compiler.cpp
@@ -121,6 +121,23 @@ BOOST_AUTO_TEST_CASE(switch_inconsistent_return_count)
 	BOOST_CHECK(!successCompile(sourceCode));
 }
 
+BOOST_AUTO_TEST_CASE(disallowed_asm_instructions)
+{
+	for (unsigned i = 1; i <= 32; i++)
+		BOOST_CHECK(!successCompile("(asm PUSH" + boost::lexical_cast<string>(i) + ")"));
+}
+
+BOOST_AUTO_TEST_CASE(disallowed_functional_asm_instructions)
+{
+	for (unsigned i = 1; i <= 32; i++)
+		BOOST_CHECK(!successCompile("(PUSH" + boost::lexical_cast<string>(i) + ")"));
+	for (unsigned i = 1; i <= 16; i++)
+		BOOST_CHECK(!successCompile("(DUP" + boost::lexical_cast<string>(i) + ")"));
+	for (unsigned i = 1; i <= 16; i++)
+		BOOST_CHECK(!successCompile("(SWAP" + boost::lexical_cast<string>(i) + ")"));
+	BOOST_CHECK(!successCompile("(JUMPDEST)"));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }