Add support for do/while loops

This commit adds support for a standard do <statement> while <expr>;
form of statement.  While loops were already being supported; supporting
a do/while loop mostly involves reusing code from while loops but putting
the conditional checking last.

1 files changed, 16 insertions, 3 deletions

diff --git a/libsolidity/codegen/ContractCompiler.cpp b/libsolidity/codegen/ContractCompiler.cpp
index ebb84784..1404963f 100644
--- a/libsolidity/codegen/ContractCompiler.cpp
+++ b/libsolidity/codegen/ContractCompiler.cpp
@@ -611,12 +611,25 @@ bool ContractCompiler::visit(WhileStatement const& _whileStatement)
 	m_breakTags.push_back(loopEnd);
 
 	m_context << loopStart;
-	compileExpression(_whileStatement.condition());
-	m_context << Instruction::ISZERO;
-	m_context.appendConditionalJumpTo(loopEnd);
+
+	// While loops have the condition prepended
+	if (!_whileStatement.isDoWhile())
+	{
+		compileExpression(_whileStatement.condition());
+		m_context << Instruction::ISZERO;
+		m_context.appendConditionalJumpTo(loopEnd);
+	}
 
 	_whileStatement.body().accept(*this);
 
+	// Do-while loops have the condition appended
+	if (_whileStatement.isDoWhile())
+	{
+		compileExpression(_whileStatement.condition());
+		m_context << Instruction::ISZERO;
+		m_context.appendConditionalJumpTo(loopEnd);
+	}
+
 	m_context.appendJumpTo(loopStart);
 	m_context << loopEnd;