Merge pull request #2399 from ethereum/lll-if

LLL: Replace obsolete assembly code

4 files changed, 73 insertions, 20 deletions

diff --git a/libevmasm/Assembly.cpp b/libevmasm/Assembly.cpp
index 92a4c2a4..606714d2 100644
--- a/libevmasm/Assembly.cpp
+++ b/libevmasm/Assembly.cpp
@@ -55,9 +55,6 @@ void Assembly::append(Assembly const& _a)
 	m_subs += _a.m_subs;
 	for (auto const& lib: _a.m_libraries)
 		m_libraries.insert(lib);
-
-	assert(!_a.m_baseDeposit);
-	assert(!_a.m_totalDeposit);
 }
 
 void Assembly::append(Assembly const& _a, int _deposit)
diff --git a/libevmasm/Assembly.h b/libevmasm/Assembly.h
index d1cfc7ef..0d40abcf 100644
--- a/libevmasm/Assembly.h
+++ b/libevmasm/Assembly.h
@@ -85,12 +85,6 @@ public:
 	AssemblyItem const& back() const { return m_items.back(); }
 	std::string backString() const { return m_items.size() && m_items.back().type() == PushString ? m_strings.at((h256)m_items.back().data()) : std::string(); }
 
-	void onePath() { assertThrow(!m_totalDeposit && !m_baseDeposit, InvalidDeposit, ""); m_baseDeposit = m_deposit; m_totalDeposit = INT_MAX; }
-	void otherPath() { donePath(); m_totalDeposit = m_deposit; m_deposit = m_baseDeposit; }
-	void donePaths() { donePath(); m_totalDeposit = m_baseDeposit = 0; }
-	void ignored() { m_baseDeposit = m_deposit; }
-	void endIgnored() { m_deposit = m_baseDeposit; m_baseDeposit = 0; }
-
 	void injectStart(AssemblyItem const& _i);
 	int deposit() const { return m_deposit; }
 	void adjustDeposit(int _adjustment) { m_deposit += _adjustment; assertThrow(m_deposit >= 0, InvalidDeposit, ""); }
@@ -121,7 +115,6 @@ protected:
 	/// returns the replaced tags.
 	std::map<u256, u256> optimiseInternal(bool _enable, bool _isCreation, size_t _runs);
 
-	void donePath() { if (m_totalDeposit != INT_MAX && m_totalDeposit != m_deposit) BOOST_THROW_EXCEPTION(InvalidDeposit()); }
 	unsigned bytesRequired(unsigned subTagSize) const;
 
 private:
@@ -144,8 +137,6 @@ protected:
 	mutable std::vector<size_t> m_tagPositionsInBytecode;
 
 	int m_deposit = 0;
-	int m_baseDeposit = 0;
-	int m_totalDeposit = 0;
 
 	SourceLocation m_currentSourceLocation;
 };
diff --git a/liblll/CodeFragment.cpp b/liblll/CodeFragment.cpp
index 9f37bc65..afef63e9 100644
--- a/liblll/CodeFragment.cpp
+++ b/liblll/CodeFragment.cpp
@@ -439,15 +439,21 @@ void CodeFragment::constructOperation(sp::utree const& _t, CompilerState& _s)
 			int minDep = min(code[1].m_asm.deposit(), code[2].m_asm.deposit());
 
 			m_asm.append(code[0].m_asm);
-			auto pos = m_asm.appendJumpI();
-			m_asm.onePath();
+			auto mainBranch = m_asm.appendJumpI();
+
+			/// The else branch.
+			int startDeposit = m_asm.deposit();
 			m_asm.append(code[2].m_asm, minDep);
 			auto end = m_asm.appendJump();
-			m_asm.otherPath();
-			m_asm << pos.tag();
+			int deposit = m_asm.deposit();
+			m_asm.setDeposit(startDeposit);
+
+			/// The main branch.
+			m_asm << mainBranch.tag();
 			m_asm.append(code[1].m_asm, minDep);
 			m_asm << end.tag();
-			m_asm.donePaths();
+			if (m_asm.deposit() != deposit)
+				error<InvalidDeposit>();
 		}
 		else if (us == "WHEN" || us == "UNLESS")
 		{
@@ -458,11 +464,8 @@ void CodeFragment::constructOperation(sp::utree const& _t, CompilerState& _s)
 			if (us == "WHEN")
 				m_asm.append(Instruction::ISZERO);
 			auto end = m_asm.appendJumpI();
-			m_asm.onePath();
-			m_asm.otherPath();
 			m_asm.append(code[1].m_asm, 0);
 			m_asm << end.tag();
-			m_asm.donePaths();
 		}
 		else if (us == "WHILE" || us == "UNTIL")
 		{
diff --git a/test/liblll/EndToEndTest.cpp b/test/liblll/EndToEndTest.cpp
index 3668038d..a01eaca0 100644
--- a/test/liblll/EndToEndTest.cpp
+++ b/test/liblll/EndToEndTest.cpp
@@ -57,6 +57,68 @@ BOOST_AUTO_TEST_CASE(panic)
 	BOOST_REQUIRE(m_output.empty());
 }
 
+BOOST_AUTO_TEST_CASE(when)
+{
+	char const* sourceCode = R"(
+		(returnlll
+			(seq
+				(when (= (calldatasize) 0) (return 1))
+				(when (!= (calldatasize) 0) (return 2))))
+	)";
+	compileAndRun(sourceCode);
+	BOOST_CHECK(callContractFunction("test()") == encodeArgs(u256(2)));
+	BOOST_CHECK(callFallback() == toBigEndian(u256(1)));
+}
+
+BOOST_AUTO_TEST_CASE(unless)
+{
+	char const* sourceCode = R"(
+		(returnlll
+			(seq
+				(unless (!= (calldatasize) 0) (return 1))
+				(unless (= (calldatasize) 0) (return 2))))
+	)";
+	compileAndRun(sourceCode);
+	BOOST_CHECK(callContractFunction("test()") == encodeArgs(u256(2)));
+	BOOST_CHECK(callFallback() == toBigEndian(u256(1)));
+}
+
+BOOST_AUTO_TEST_CASE(conditional_literal)
+{
+	char const* sourceCode = R"(
+		(returnlll
+			(seq
+				(return (if (= (calldatasize) 0) 1 2))))
+	)";
+	compileAndRun(sourceCode);
+	BOOST_CHECK(callContractFunction("test()") == encodeArgs(u256(2)));
+	BOOST_CHECK(callFallback() == toBigEndian(u256(1)));
+}
+
+BOOST_AUTO_TEST_CASE(conditional)
+{
+	char const* sourceCode = R"(
+		(returnlll
+			(seq
+				(if (= (calldatasize) 0) (return 1) (return 2))))
+	)";
+	compileAndRun(sourceCode);
+	BOOST_CHECK(callContractFunction("test()") == encodeArgs(u256(2)));
+	BOOST_CHECK(callFallback() == toBigEndian(u256(1)));
+}
+
+BOOST_AUTO_TEST_CASE(conditional_seq)
+{
+	char const* sourceCode = R"(
+		(returnlll
+			(seq
+				(return (if (= (calldatasize) 0) { 0 2 1 } { 0 1 2 }))))
+	)";
+	compileAndRun(sourceCode);
+	BOOST_CHECK(callContractFunction("test()") == encodeArgs(u256(2)));
+	BOOST_CHECK(callFallback() == toBigEndian(u256(1)));
+}
+
 BOOST_AUTO_TEST_CASE(exp_operator_const)
 {
 	char const* sourceCode = R"(