Fix continue inside do-while.

Changelog.md

@@ -4,6 +4,7 @@
 Breaking Changes:
  * Disallow conversions between bytesX and uintY of different size.
  * Commandline interface: Require ``-`` if standard input is used as source.
+ * General: ``continue`` in a ``do...while`` loop jumps to the condition (it used to jump to the loop body). Warning: this may silently change the semantics of existing code.
  * Type Checker: Disallow arithmetic operations for Boolean variables.
 
 Features:

libsolidity/codegen/ContractCompiler.cpp

@@ -666,32 +666,36 @@ bool ContractCompiler::visit(WhileStatement const& _whileStatement)
 {
 	StackHeightChecker checker(m_context);
 	CompilerContext::LocationSetter locationSetter(m_context, _whileStatement);
+
 	eth::AssemblyItem loopStart = m_context.newTag();
 	eth::AssemblyItem loopEnd = m_context.newTag();
-	m_continueTags.push_back(loopStart);
 	m_breakTags.push_back(loopEnd);
 
 	m_context << loopStart;
 
-	// While loops have the condition prepended
+	if (_whileStatement.isDoWhile())
-	if (!_whileStatement.isDoWhile())
 	{
-		compileExpression(_whileStatement.condition());
+		eth::AssemblyItem condition = m_context.newTag();
-		m_context << Instruction::ISZERO;
+		m_continueTags.push_back(condition);
-		m_context.appendConditionalJumpTo(loopEnd);
-	}
 
 		_whileStatement.body().accept(*this);
 
-	// Do-while loops have the condition appended
+		m_context << condition;
-	if (_whileStatement.isDoWhile())
+		compileExpression(_whileStatement.condition());
+		m_context << Instruction::ISZERO << Instruction::ISZERO;
+		m_context.appendConditionalJumpTo(loopStart);
+	}
+	else
 	{
+		m_continueTags.push_back(loopStart);
 		compileExpression(_whileStatement.condition());
 		m_context << Instruction::ISZERO;
 		m_context.appendConditionalJumpTo(loopEnd);
-	}
+
+		_whileStatement.body().accept(*this);
 
 		m_context.appendJumpTo(loopStart);
+	}
 	m_context << loopEnd;
 
 	m_continueTags.pop_back();

test/libsolidity/SolidityEndToEndTest.cpp

@@ -482,6 +482,27 @@ BOOST_AUTO_TEST_CASE(do_while_loop)
 	testContractAgainstCppOnRange("f(uint256)", do_while_loop_cpp, 0, 5);
 }
 
+BOOST_AUTO_TEST_CASE(do_while_loop_continue)
+{
+	char const* sourceCode = R"(
+		contract test {
+			function f() public pure returns(uint r) {
+				uint i = 0;
+				do
+				{
+					if (i > 0) return 0;
+					i++;
+					continue;
+				} while (false);
+				return 42;
+			}
+		}
+	)";
+	compileAndRun(sourceCode);
+
+	ABI_CHECK(callContractFunction("f()"), encodeArgs(42));
+}
+
 BOOST_AUTO_TEST_CASE(nested_loops)
 {
 	// tests that break and continue statements in nested loops jump to the correct place